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CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. provisional application No. 60/287197, filed Apr. 27, 2001.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates generally to retractable awnings and more particularly to a manual deployment system for moving the awning from a retracted position to an extended position.
[0004] 2. Description of the Relevant Art
[0005] Retractable awnings have been in use for many years, with early uses being primarily as covers for windows, doors and the like. More recently, retractable awnings have been designed for use on mobile structures such as recreational vehicles and mobile homes, and, accordingly, out of necessity, the awnings have needed to include more sophisticated systems of operation and for retaining the awnings in either retracted or extended positions. Further, awnings for recreational vehicles and mobile homes are fairly long so as to extend along a substantial portion of the side of the vehicle, and, accordingly, they are relatively heavy and are sometimes difficult to manipulate.
[0006] In an effort to make deployment of the awning system easier, an automated awning system was developed and is disclosed in pending application Ser. No. 09/586,945, filed Jun. 2, 2000, for a Powered Retractable Awning, which is of common ownership with the present application and is hereby incorporated by reference in its entirety. The automated awning basically operates by having a motor that causes an awning roll bar to rotate in either direction thereby causing the awning sheet on the roll bar to either unroll and extend or roll and retract. While the automated awning overcomes problems inherent in other prior art systems, it is relatively expensive to manufacture due to the motorized automatic operation of the awning.
[0007] In an effort to create a lower cost deployment system that still overcomes the shortcomings of prior art systems, a subsequent manual deployment system with easier deployment features was developed and is disclosed in pending U.S. provisional application Serial No. 60/253180, filed Nov. 27, 2000, for an Easy Deployment Retractable Awning, which is of common ownership with the present application and is hereby incorporated by reference in its entirety.
[0008] The aforenoted Easy Deployment Retractable Awning is simply moved from its retracted to its extended position by pulling the awning roll bar away from the support surface causing the awning sheet to unwrap from the roll bar and the support arms and rafter arms to automatically deploy until the awning is fully extended. To pull the awning roll bar away from the support surface, one must manually grasp a pull-down strap on a center portion of the roll bar and pull downwardly causing the awning sheet to unwrap from the roll bar. However, both the height of the roll bar and the strength required to pull the roll bar downwardly are sometimes difficult tasks for the awning system user to undertake. The problem is further exacerbated by the fact that many recreational vehicles are owned and operated by elderly individuals who do not always have the strength of younger individuals, and many times the elderly have some difficulty in extending the awning.
[0009] Accordingly, means for more easily extending a retractable awning from its retracted position would be desirable in the retractable awning industry.
[0010] It is to overcome the shortcomings in prior art awning systems and to provide a dependable and easily undertaken means for extending a retractable awning that the present system has been developed.
SUMMARY OF THE INVENTION
[0011] The present invention relates to a system for more easily extending a typical retractable awning that includes a roll bar about which an awning sheet or canopy can be wrapped with one edge of the awning sheet being secured to a supporting surface and the other edge to the roll bar. A pair of support arms and rafter arms are operably supported on the support surface and connected to the roll bar in a manner so as to permit the roll bar to move between a retracted position adjacent to the support surface and an extended position displaced from the support surface.
[0012] As the roll bar moves from the retracted to the extended position, the support arms automatically extend telescopically while the rafter arms unfold about an elbow member approximately midway along the length of the rafter arms. When the awning is fully deployed, it is retained in the extended position by lock mechanisms provided in the support arms and/or rafter arms.
[0013] The present invention in its preferred embodiment includes a pull strap having a length and plurality of loops or pockets along its length. The strap includes two ends, a free end and an end adapted for connection to the roll bar. The system also includes a shaped or pre-contoured pull rod having two end segments and at least one intermediate handle or gripping segment between the end segments. At least one of the end segments of the rod is adapted for releasable connection to the free end of the strap. The pull strap is connected to the roll bar such that when the pull strap is pulled by the pull rod, the roll bar is caused to rotate thereby allowing the awning sheet to unroll from the roll bar.
[0014] Other aspects, features, and details of the present invention can be more completely understood by reference to the following detailed description of the preferred embodiment, taken in conjunction with the drawings and from the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] [0015]FIG. 1 is a front isometric view of a recreational vehicle with an awning system in its retracted position and a user connecting one end of the present invention pull rod with one end of the present invention pull strap.
[0016] [0016]FIG. 2 is an enlarged cut-away view of the awning system awning sheet and the present invention pull strap and pull rod in FIG. 1.
[0017] [0017]FIG. 3 is an isometric view of a user with one hand on the end handle portion of the pull rod and a second hand on a second handle portion near the middle of the pull rod while the other end of the pull rod is connected with the pull strap (which is connected with the awning sheet roll).
[0018] [0018]FIG. 4 is an isometric view of a user with one hand on the handle portion near the middle of the pull rod and a second hand grasping a portion of one layer of the pull strap between the end of the strap and a first point where the strap layers are joined (the strap is connected with the awning sheet roll).
[0019] [0019]FIG. 5 is a front isometric view of a recreational vehicle with an awning system in its extended position and a user pulling a pull strap connected to the awning sheet roll of the awning system.
[0020] [0020]FIG. 6 is a section view taken along line 6 - 6 of FIG. 5.
[0021] [0021]FIG. 7 is a top plan view of the pull rod.
[0022] [0022]FIG. 8 is an enlarged front isometric view of the pull strap end that connects with the pull rod.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0023] The system of the present invention finds usefulness in a retractable awning 10 of a type shown in FIGS. 1 and 5 mounted on the side 12 of a recreational vehicle 14 or other supporting surface. Awnings of this type are well known in the art with an example of such being described in U.S. Pat. No. 5,560,412, which is of common ownership with the present application and incorporated by reference herein. The awnings of this type include an awning sheet or canopy 16 that is secured along one edge to a supporting surface, such as the side wall 12 of the recreational vehicle or the like and an opposite edge which is secured to a roll bar 18 about which the canopy can be rolled when the awning is moved from an extended position (FIG. 5) to a retracted position (FIG. 1). The awning further includes a pair of support arms 20 having their outer ends rotatably connected to an associated end of the roll bar 18 and their inner ends pivotally mounted on support brackets adjacent to a lower edge of the side wall 12 . The support arms are typically telescopic in construction so that the length thereof can be extended or retracted as the awning is moved between extended and retracted positions. A pair of rafter arms 24 also support opposite ends of the roll bar 18 with the rafter arms having an inner end secured to brackets 26 on the side wall 12 adjacent a top edge thereof. The rafter arms are typically collapsible such as with the use of an elbow joint or the like (not shown) at a mid-point along their length. The roll bar is typically a tubular member having a plurality of longitudinally extending circumferentially spaced recesses 28 (FIG. 6) formed in its outer surface with one of those recesses (not seen) receiving and securing the outer edge of the awning sheet, another recess (not seen) receiving an edge of a valance 30 and another recess 31 (FIG. 6) receiving one end 32 of a pull strap 34 utilized by an operator in moving the awning from the retracted position of FIG. 1 to the extended position of FIG. 5.
[0024] The connection of the pull strap 34 to the roll bar is best illustrated in FIG. 6 and as can be appreciated, when the awning is being retracted from the extended position of FIGS. 5 and 6 to the retracted position of FIG. 1, the pull strap is being wrapped around the roll bar along with the awning sheet 16 and valance 30 until the awning sheet, pull strap and valance are substantially fully wrapped around the roll bar 18 . When fully retracted, the opposite or free end 36 of the pull strap is exposed slightly as seen in FIG. 2 so that an operator of the awning can grasp the free end of the pull strap and, by pulling the pull strap downwardly and outwardly, extend the awning from the retracted position of FIG. 1 to the extended position of FIG. 5. As can be appreciated, as the awning is being extended, the pull strap is unwrapped from the roll bar.
[0025] As might be appreciated, and as mentioned previously, awnings of this type are relatively heavy and can be cumbersome to operate particularly for elderly individuals. Accordingly, and in accordance with the present invention, the pull strap has been uniquely designed for cooperative use with a uniquely designed pull cane or rod 38 .
[0026] The pull strap 34 has a length that is approximately the same as the depth of the awning sheet 16 and the strap may be made of an elongated strip of webbing or other non-elastic material which has been folded upon itself and stitched at 40 , or otherwise secured transversely, at longitudinally spaced locations as shown in FIG. 8 to define a plurality of adjacent pockets 42 along the length of the strap. The strap of course could be formed in many other manners consistently with the present invention such as a single strip of webbing could have loops of webbing or other materials (not shown) secured thereto or formed therefrom defining pockets at spaced intervals along the length of the strap.
[0027] The pull rod or cane 38 is rigid and uniquely designed to have an outer end 44 adapted to be releasably connected to the pull strap, an inner end 46 adapted to be grasped by an operator of the awning and one or more intermediate gripping locations 48 (only one being illustrated) between the outer and inner ends of the pull rod. In the disclosed embodiment seen best in FIGS. 2 and 7, the outer and inner ends of the pull rod are relatively short segments and are parallel with each other and as illustrated are horizontally disposed when the rod is in use. The single intermediate gripping area or segment 48 of the pull rod is also parallel with the outer and inner segments and of approximately the same length. In between the outer segment and the intermediate gripping segment is a relatively long, straight outer connecting segment 50 that is disposed at an acute angle to the outer segment 44 and the gripping segment 48 and assumes approximately one-half of the overall length of the pull rod. An elongated, straight inner-connecting segment 52 extends from the inner end 46 of the rod to the intermediate gripping segment 48 so as to extend in parallel but longitudinally spaced relationship with the outer elongated connecting segment 50 . As will be appreciated with the description of the operation of the device hereafter, the pull rod 38 could be made with more than one intermediate gripping segment 48 by repeating the same pattern with connecting segments as described.
[0028] In operation, as shown in FIGS. 1 - 5 , an operator of the system grips the inner segment 46 of the pull rod 38 and inserts the outer segment 44 of the pull rod into a loop 54 at the outer or free end 36 of the pull strap. The operator then pulls downwardly on the inner segment of the pull rod causing the awning and the pull strap to extend from the retracted position of FIG. 1 and after the pull strap has been partially extended along with the awning, the operator can use his other hand to grasp the intermediate gripping segment of the pull rod as shown in FIG. 3 and with further extension of the awning, the operators first hand can then be used to grip the free end 36 of the pull strap as in FIG. 4. From this position, the pull strap can be fully extended or unwrapped from the roll bar placing the roll bar in the position of FIGS. 5 and 6 and thereafter the awning can be locked in the extended position with conventional locks (not shown) on the support arms and/or rafter arms. The pull strap 34 can then be tucked between the roll bar 18 and the awning sheet 16 in an out of the way location or can be slid to one end or the other of the roll bar and draped over the adjacent rafter arm 24 , for example, to keep the pull strap in an out of the way location.
[0029] It will be appreciated from the above that a system for deploying a retractable awning is simple in construction and easy to operate even for the elderly.
[0030] In other embodiments of the pull strap (not shown), the strap could be configured from three or more layers of material with loops or pockets configured on only the exterior layers of the material. In another embodiment, the pull strap could be configured from one layer of material with only portions of a second layer attached to the surface of the first layer to create handle loops or pockets. As one skilled in the art will realize, many different embodiments are possible that would enable the user to pull the pull strap without having to overreach or use elevation means.
[0031] Although a typical awning sheet manual extension system has been described with a certain degree of particularity, it is understood that the present disclosure has been made by way of example, and changes in detail or structure may be made without departing from the spirit of the invention as defined in the appended claims.
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An awning sheet manual extension system includes a pull strap having a length and longitudinally spaced pockets. The strap includes two ends with one end being adapted for connection to a roll bar of an awning incorporating the pull strap. The system also includes a shaped pull rod having two end segments and at least one intermediate handle portion. At least one of the end segments of the rod is adapted for releasable connection with a free end of the strap. The pull strap is connected to the roll bar such that when the pull strap is pulled by the pull rod, the roll bar is causing to rotate thereby causing the awning sheet to unroll from the roll bar.
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BACKGROUND OF THE INVENTION
The present invention relates to a process for repairing flexible articles, and, more particularly, to a process for repairing vinyl base materials such as automotive upholstery and vinyl tops.
Vinyl materials have become extremely popular for use in automobiles, home furnishings and the like. The surface of vinyl materials can be textured to simulate almost any pattern desired. An example of this is simulated leather upholstery.
Vinyl materials can become damaged. Damage to the material by cigarette burns, knife cuts, tears, splits, and the like are examples.
U.S. Pat. No. 3,620,865 describes a process for repairing damaged flexible vinyl materials by applying successive, thin layers of a liquid vinyl-welding compound to a prepared hole in a damaged vinyl base material. Each layer is cured by application of heat. Before applying a successive layer, it is necessary to cool each cured layer to prevent premature curing of the bottom portion of the successive layer. Premature curing of the repair causes weakness due to variations in the strength of the repair across its thickness. Although this process has proven to be useful, it is not without disadvantages.
Among the disadvantages is that it is necessary to closely control the viscosity of the liquid vinyl-welding compound during repair. If the viscosity is too low the liquid will run and not stay in the hole being filled. If the compound is too thick, effective curing is impossible without damaging the vinyl base material because much of the heat applied to cure the welding compound will reach the base material surrounding the welding compound. On the other hand, if the heat is reduced to prevent damage to the vinyl base material, only the surface of a thick layer of weld compound will be cured. As a consequence, the weld compound must be layered into the vinyl base material and cured after each layer has been applied. Generally speaking, with most vinyl base material thicknesses, approximately four layers are required. Because many layers are required and each layer must be cooled before the subsequent layer can be applied, the repair process often is very time consuming, particularly when thick base material is being repaired.
Another disadvantage of repair with a liquid welding compound is that curing time depends upon may variables, such as the temperature of the heat source, humidity, ambient temperature, and thickness of the liquid layer. Because these variables are difficult, and in some cases impossible to control, it is impossible to predict how long a layer should be exposed to the heat source for complete cure. Therefore, some repairs are made with incompletely cured vinyl layers, with resulting loss in strength and wear resistance. The tendency in practice is to be conservative and overheat the welding compound, which is both time consuming and creates the risk of degrading the welding compound, the vinyl base material, or both.
Other prior art describes a process for repairing damaged flexible vinyl base materials by applying one layer of vinyl adhesive tape over the damaged hole in a vinyl base material and melting the vinyl into the hole and over the damaged vinyl base material. The disadvantage of this approach is that the vinyl tape material used shrinks when heat is applied so that a butt type joint between the vinyl tape and the edge of the hole cannot be used. Instead, a lap type joint must be used, with an unattractive lumpy and uneven appearance resulting.
SUMMARY OF THE INVENTION
The present invention envisions the use of one or more precured layers of a flexible, high strength, substantially non-heat shrinkable, and low fusion point vinyl-welding compound fused to a prepared area of a damaged vinyl article which, after fusing, is grained if desired.
In a specific form, the method of the present invention includes applying successive layers of a precured welding compound to a prepared hole in a vinyl base material to be repaired. An initial precured layer is applied over a backing material, for example, the metal roof on an automobile in the case of repair to a vinyl top, or sponge rubber in the case of a repair to an automobile seat. This layer is proximated to the edge of the hole and fused to the base material by heat to form a butt joint. In identical fashion an intermediate layer or layers and a final layer are integrated to the base material above the first layer. Before fusing the final layer, it is smoothed or leveled for continuity with the surface of the vinyl base material. After leveling, the last layer is fused to the vinyl base material by heat.
In one embodiment of the invention, all layers but the last layer is unpigmented and of a different color than the base material, and the last layer is pigmented to match the color of the base material. Because the initial and intermediate layers are not the same color as the base material, it is possible to observe if the precured material actually fuses into the vinyl base material, thereby allowing the operator to be certain that a strong weld is obtained.
In another embodiment of the invention, only one precured layer of thickness approximately equal to the thickness of the vinyl base material is used in order to quickly repair a damaged vinyl article. After preparing the vinyl base material the precured layer is applied over a backing material, smoothed or leveled to present a repair which is continuous with the surface of the vinyl base material, and then fused to the base material by heat.
When the vinyl base material has a grain texture, a grain texture may be applied to the welding compound using a graining tool having a die face with the required grain pattern. This tool is applied to the upper layer of the welding compound after it is fused to the vinyl base material. The upper layer is heated to soften the surface of the layer and adjacent vinyl material surrounding the layer for reception of the impression of the die. The die is applied to this heated area to feather the surface of the base material proximate the repair. The resulting surface is cooled before removal of the graining tool, as by cooling the graining tool with a wet cloth or sponge.
When the vinyl base material is pigmented, the repaired area of the vinyl base material may be colored with a vinyl coloring material. Alternatively, pigmented precured welding compound matching the vinyl base material may be used for effecting the repair, preferably only for the last layer.
The process of the present invention provides an expedient and cheap way of repairing vinyl flexible materials which have been damaged by ripping, tearing, burning or the like. Repairs made with this process typically take only about one fourth the time required for repairs made with liquid vinyl compounds because the curing and cooling steps are eliminated. The process produces a repair which is essentially identical in appearance to the vinyl base material being repaired. The repair is strong and has excellent wear resistance because the precured welding compound is optimumly cured in the controlled environment of a factory with special curing equipment rather than in the uncontrolled environment of the field.
These and other features, aspects, and advantages of the present invention will become more apparent from the following description, appended claims, and drawings.
BRIEF DESCRIPTION OF THE FIGURES
FIG. 1 depicts two layers of precured weld compound applied to a repaired hole of a flexible vinyl material such as the vinyl top on an automobile roof; and
FIG. 2 is a view showing the finishing of a repair.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The process of the present invention contemplates the preparation of a damaged area in a vinyl base material by removing loose, damaged and frayed base material. This can be done with a sharp instrument such as a knife or razor blade. The object is to get a clean and sharp edge bounded on one side by the area to be repaired and on the other with undamaged vinyl. In the event that the repair is to a razor-type cut, the cut or slit is opened by cutting a little base material away to develop a wider slit, for example, about a one sixteenth of an inch. This provides room for precured vinyl welding compound, hereinafter described, and ensures a strong fusion bond between the welding compound and the base material being repaired.
Further preparation of the joint may be required where the vinyl material is glued to a substrate such as a car roof. Glue adversely affects the vinyl-welding material by causing it to crack. Therefore, any regluing which must be done to the vinyl base material should be done without allowing glue to get onto the substrate over which the vinyl-welding material is to be applied or on the peripherial edges of the hole.
In order to obtain satisfactory fusion between the vinyl-welding compound and the base material being repaired, it is necessary that the vinyl base material defining the repair hole or slit be thoroughly cleaned. This may be done with any good quality solvent such as toluol which will remove grease and the like to present a clean vinyl surface without leaving a residue. In addition to grease removal, it is preferred that a mild vinyl solvent be used to clean a small film of vinyl off the area of the base material bounding the repair hole to be sure that all foreign matter is removed. The removal of foreign matter from the surface of the vinyl base material bounding the hole is necessary if edge lifting is to be avoided.
After the area of the surface of the vinyl material to be repaired has been thoroughly cleaned, it must dry. Drying may be done by wiping the solvent cleaners away and by the application of heat as from a commercially available heat gun.
The vinyl-welding compound used in repairing a damaged vinyl article is a vinyl compound having a high tensile strength relative to the vinyl base material but with a fusion point compatible with the base material. The requirement of a low fusion point is necessary to prevent damage to the base material during the curing of the welding compound. The following table shows satisfactory ingredients for a welding compound. The amounts shown are for a 90-gallon batch.
TABLE 1______________________________________ Parts by WeightDiamond PVC 7401 360 lbs. 0.445Diamond PVC 71 120 lbs. 0.150Diisodecyl Phalate (DIDP) 320 lbs. 0.395Ferro 1777 3,600 g.ms 0.010______________________________________
Diamond PVC 7401 has a low fusion temperature and relatively low tensile strength. The addition of Diamond PVC 71 to PVC 7401 increases tensile strength but also increases the fusion temperature. Diamond PVC 7401 is a copolymer of vinyl chloride and polyvinyl acetate manufactured by the dispersion method. Diamond PVC 71 is a homopolymer of polyvinyl chloride manufactured by the dispersion method which has a fusion temperature of from between about 325° to 350° F. The balance shown in the table has proven highly satisfactory in accommodating both the requisites of tensile strength and fusion temperature. The diisodecyl phalate is used to increase the flexibility of the welding compound. If too much of this plasticizer is used, the welding compound loses desirable tensile strength. The ferro 1777 is a stabilizer. It is a calcium-zinc organic inhibitor. The composition set forth above is a thermoplastic and thermosetting material which must be cured.
The liquid welding compound is cured in various thicknesses at temperatures from 280° to 375° F. by preheating two metal plates to the desired temperature and placing liquid welding compound between the plates. One of the two plates has projections whose height is approximately equal to the desired thickness of the cured layer, usually from about 0.010 to about 0.050 inches. Preferably, curing heat is provided by electric coils in one or both of the plates.
The process of the present invention contemplates that one or more layers of the precured weld compound be placed into the hole in the vinyl base material and fused to the edge of the vinyl base material surrounding the hole with application of heat to give a butt joint. One precured layer whose thickness is approximately equal to that of the vinyl base material is used. Alternatively, successive layers of precured material whose combined thickness approximates that of the vinyl base material are used.
The repair must be backed in order to prevent the compound from sagging through the hole. Normally the backing is provided by seat cushion material, or in the case of vinyl tops, the steel automobile roof. If backing is not so provided, then some form of backing must be used. Thus, when the sponge rubber used in any automobile upholstery applications is split in the area to be fixed, sponge rubber split is filled with, for example, cotton.
Another consideration should be observed if grain flattening of the vinyl base material is to be avoided in situations where the substrate absorbs considerable amounts of the heat applied during fusing. This situation occurs, for example, in vinyl top repairs where the steel substrate absorbs and retains heat applied with a heat gun. This applied heat causes the grain of the base material to flatten. To prevent this, an insulating layer of, say cardboard, should be placed between the metal and welding compound.
The application of precured welding compounding to holes in a vinyl material is schematically shown in the Figures. The Figures illustrate a substrate or backing 11, for example a car roof, a prepared hole 12, and a vinyl base material 13 overlying the substrate bounding hole 12. An initial precured layer 15 of welding compound is laid into the hole. This layer is proximated to the edge of the hole to butt against the vinyl base material surrounding the hole. The layer is fused with the vinyl base material by the application of heat through a device such as a heat gun. Therefore the demarcation between the precured layer 15 and the vinyl base material 13 is not actually present.
In identical fashion, an intermediate layer 16 is applied to the hole and fused to the surrounding vinyl base material. Because the vinyl welding compound is precured, it is not necessary to wait until the initial layer 15 cools to prevent premature curing before applying the intermediate layer 16. This allows a repair to be made quickly.
In identical fashion, additional intermediate layers (not shown) are applied to the hole to build up the repair until its thickness differs from the thickness of the vinyl base material by about the thickness of one layer of precured welding compound.
As shown in FIG. 1, the combined thicknesses of layers 15 and 16 is less than the thickness of the vinyl base material 13. Thus, a final precured layer 17 is needed so that the surface of the repair will be even with the surface of the base material. Although using more than one precured layer to effect the repair takes longer than using only one precured layer, there is an advantage to be realized through the use of more than one layer since the top layer can be pigmented to match the vinyl base material, and thus the bottom and intermediate layers may be clear or colored different from the color of the base material. Because the bottom and intermediate layers are not the same color as the base material it is possible to observe if the precured material actually fuses into the vinyl base material, thereby allowing the operator to be certain that a strong weld is obtained. When only one layer is used to repair the damaged vinyl base material, the thickness of the layer necessarily approximates the thickness of the vinyl base material.
The final layer 17 is applied just as the initial precured layer 15 is applied, but it must be smoothened or leveled flush with the level of the upper surface of the vinyl base material before heating. After it is leveled, it is fused by the application of heat to the vinyl base material. The leveled or smoothened repair is indicated by reference numeral 18. Again it should be emphasized that the repair material after curing is fused with the vinyl base material, and therefore the illustrated distinctive boundary between the two is not in fact present.
The color of the repair may be made to match that of the vinyl base material by coloring it with a vinyl paint, if so desired. Alternately and preferably pigment is added to the welding compound used for the last layer before it is cured so that upon cure the repair will match the vinyl base material.
Generally, the grain or surface texture of the vinyl base material must be duplicated in the exposed surface of the cured welding compound. This is done by a graining tool 19 which is applied to a heated and softened surface of the weld compound and adjacent vinyl base material.
The graining tool is made with a relatively hard but yet flexible material which has a die surface with the impression of the grain pattern or surface texture desired. The graining tool may be fabricated from the ingredients and in the proportions listed below in table II.
TABLE II______________________________________Reichold polyester resin 32-345 450 lbs.Reichold polyester resin 31-851 50 lbs.Calcium carbonate 400 lbs.Talc 100 lbs.______________________________________
The polyester resin 32-345 has a very good curing rate and is dry to the touch after it cures, due to the presence of metallic drying agents. It is resilient but not flexible, that is, it is stiff. The polyester resin 31-851 is added to enhance flexibility and therefore reduces the stiffness which would result from the exclusive use of the polyester resin 32-345. These polyesters do not adhere to the vinyl material of the repair and base material. Both resins are a semisaturated polymer where some of the saturated adipic acids have been replaced with some phthalic anhydrides and some of the propylene glycols have been replaced by the more flexible diethylene glycol. Both resins also have a styrene monomer which forms a polyester monomer with an acid value of from between 20 to 25. Resin 31-851 has more diethylene glycol than resin 32-345 to add flexibility.
The calcium carbonate is an extender to reduce the cost of the compound used in fabricating the grain-on tools. The talc has absorption qualities that are used for the purpose of adjusting viscosity.
A mold release of, say, silicone is placed over the vinyl base material. The grain-on compound just described is poured on a flat, nonporous surface and mixed with an activator. The activated grain-on compound is then removed from the surface and applied over the area of the vinyl base material which has been coated with the silicone mold release. The activated grain-on compound is then leveled as by a spatula or stick.
Preferably, a backing of a second piece of vinyl having the grain or surface texture of the piece being repaired is placed on the grain-on compound before it sets up. The canvas or fabric side of this backing vinyl piece contacts the grain-on compound in order to show the grain texture. Pressure is applied to the grain-on compound and backing strip while they are still on the vinyl base material, as by a board or small weight. After a period of time, the grain-on compound will set and harden. It may then be peeled off the vinyl base material. The resulting grain-on tool has a die face with the impression of the grain or surface texture of the vinyl base material.
The grain-on tool may be registered or indexed with a repetitive pattern of the vinyl base material. This is done by aligning the backing vinyl piece with an identical pattern on the base material before the grain-on compound has set. The backing vinyl piece can then be indexed with the area of the vinyl base material surrounding the repair.
A grain is applied by the graining tool by softening the surface of the upper layer of weld compound and the adjacent surface of the vinyl base material and then applying the grain-on tool 19 over the upper surface and adjacent surface of the vinyl base material under pressure exerted with a pallet knife 20 or similar device. After a small period of time, for example, 5 seconds, and after cooling the grain-on tool as by a wet cloth or sponge, the tool is removed. Color may be applied to the repaired area through a vinyl color spray.
The present invention has been described with reference to a preferred embodiment. The spirit and scope of the appended claims should not, however necessarily be limited to this description.
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Base vinyl material is readied for repair by preparing the edges of a hole to get a clean sharp periphery, and by cleaning the base material. A substantially non-heat shrinkable, precured, vinyl-welding compound having high tensile strength and low fusion point is laid in the hole so that it abuts against the periphery of the hole and then is fused to the base material by heat. The upper exposed surface of the repair is smoothed to present a continuous, uninterrupted surface with the base material. A hard and flexible graining tool is obtained from an impression of the base material. The graining tool is applied to the upper surface of the welding compound after it and the surrounding base material have been heated sufficiently to receive a grain impression.
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[0001] This application claims the benefit of U.S. Provisional Patent Application No. 60/883,348 filed on Jan. 4, 2007. Said application is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] This invention relates to gas handling techniques, and more specifically to fast gas handling (increase/decrease of gas pressure) in a vacuum chamber. It is useful for vacuum sputtering apparatus especially for high pressure applications at high throughput at short cycle times.
BACKGROUND OF THE INVENTION
[0003] Sputtering is a physical vapor deposition (PVD) process in vacuum whereby atoms in a solid target material are ejected into the gas phase due to bombardment of the material by energetic ions. The energetic ions are in the state of the art produced by ionization from inert gas, mostly argon. Sputtering is commonly used for thin-film deposition, as well as analytical techniques. Many processes in PVD (or chemical vapor deposition (CVD)) processing of substrates in a vacuum chamber require precise and fast variation of gas pressure. One typical application is high pressure sputtering in a multi chamber vacuum system where substrates are treated at high gas pressure while transport from one chamber to the other should be performed at significantly lower pressure in order not to disturb the neighboring chambers. Many of these applications (e.g. processing of disk-like substrates for the optical or magnetic datastorage industry) require short process times in order to guarantee high throughput.
[0004] One specific application is processing of magnetic disks for PMR (perpendicular magnetic recording), a technology used to increase storage density compared to commonly known LMR (longitudinal magnetic recording). The storage layer of current PMR media consists of a granular material like CoCrPt—SiO 2 deposited on a Ru layer, both sputtered at very high pressures (up to 1×10 −1 hPa) in order to optimize magnetic properties. Best performance concerning SNR (signal to noise ratio) has been achieved by sputtering the Ru layer in two steps (“2-step Ru”): A first layer is sputtered at low to medium pressure (10 −3 hPa regime); a second layer is sputtered at very high pressure (10 −2 to 10 −1 hPa regime). The second layer at high pressure produces the desired grain size distribution for the above storage layer of about 6 nm whereas it has been speculated that the 1st layer is necessary to initiate the desired c-axis orientation of the Ru and/or reduce magnetic coupling between the SUL (soft magnetic underlayer) and the storage layer.
KNOWN TECHNOLOGIES
[0005] A mass flow controller (MFC) is a device used to measure and control the flow of gases. A mass flow controller is designed and calibrated to control a specific type of gas at a particular range of flow rates. The MFC can be given a setpoint from 0 to 100% of its full scale range but is typically operated in the 10 to 90% of full scale where the best accuracy is achieved. The device will then control the rate of flow to the given setpoint. All mass flow controllers have at least an inlet port, an outlet port, a mass flow sensor and a proportional control valve. The MFC is usually fitted with a closed loop control system which is given an input signal by the operator (or an external circuit/computer) that it compares to the value from the mass flow sensor and adjusts the proportional valve accordingly to achieve the required flow.
[0006] 1) MFCs commonly used for controlling gas flows need a considerable amount of time to stabilize gas flows after significant changing their flow set-points. FIG. 1 shows an arrangement known in the art with a gas inlet 1 , a MFC 2 , a vacuum chamber 3 , a vent-line 4 and valves 5 and 6 . It has been common practice to use such a set-up, where the gas flow from the MFC 2 is either directed into the vacuum chamber 3 or purged into a so-called vent line 4 (e.g. the forevacuum line of the vacuum system). Thus the MFC 2 can always deliver a constant flow. This set-up will be referred to as “gas purge”.
[0007] 2) Creating gas pressure peaks by gas expansion from a volume filled with gas at sufficiently high pressure (“gas expansion”) can also be considered general knowledge. A typical set-up is depicted in FIG. 2 using a combination of two switchable valves 8 and 9 : the expansion volume 7 is filled with gas from gas inlet 1 (pressure determined by the inlet pressure of the gas) while valve 8 is open and valve 9 is closed. Afterwards valve 8 is closed and the gas volume can be expanded into the vacuum chamber 3 by opening valve 9 .
[0008] 3) It is also a matter of common knowledge to use mechanical parts to narrow the pump cross-section for high pressure sputtering (“throttle valve”).
PROBLEMS IN THE ART
[0009] If substrates have to be treated at high gas pressure while trans-port from one chamber to the other should be performed at significantly lower pressure all known current approaches need significant amount of time to stabilize the pressure (in the range of seconds). For the specific case of the 2-step Ru process this film stack is currently deposited in two consecutive vacuum chambers where the first chamber is operated at low to medium pressure and the second chamber is operated at high pressure. Thus two process stations are occupied and two sets of sputtering targets are needed which both increases process costs.
BRIEF SUMMARY OF THE INVENTION
[0010] One aspect of this invention relates to a general solution for generating short pressure pulses and gas pressure stabilization especially suited for high pressure applications in vacuum processing application. In another aspect of the invention solutions for performing a 2-step process at different pressures (e.g. the 2-step Ru process) in one vacuum chamber with precise and fast gas stabilization is being described in order to enable short cycle times.
[0011] In an apparatus for controlling a gas-rise pattern in a vacuum treatment process a gas inlet ( 1 ) is operatively connected with a mass-flow-controller MFC ( 2 ); said MFC ( 2 ) being again operatively connected via a first valve ( 5 ) with a vacuum chamber ( 3 ) and in parallel via second valve ( 6 ) with a vent-line ( 4 ). Said connection with the vent-line ( 4 ) further comprises means for varying the pump cross section of said vent-line ( 4 ). In another embodiment the apparatus for controlling a gas-rise pattern in a vacuum treatment process comprises a gas inlet ( 13 ) operatively connected with a vacuum chamber ( 3 ) via a valve ( 11 ), wherein the connection between gas inlet ( 13 ) and valve ( 11 ) further comprises a diaphragm ( 12 ). Another embodiment for an apparatus for controlling a gas-rise pattern in a vacuum treatment process comprises a gas inlet ( 14 ) operatively connected with a vacuum chamber ( 3 ) via a valve ( 18 ) and a vacuum pump ( 17 ) operatively connected with the vacuum chamber ( 3 ), wherein the connection between the vacuum chamber ( 3 ) and the vacuum pump ( 17 ) further comprises a throttle valve ( 16 ). Further applications encompass the combination of embodiments described above and shown in the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIGS. 1 and 2 show arrangements known in the art to generate stable pressures or gas pulses in vacuum treatment processes respectively.
[0013] FIG. 3 shows an embodiment of the invention using a needle-valve.
[0014] FIG. 4 shows experimental results of an embodiment according FIG. 3 .
[0015] FIG. 5 shows another inventive embodiment with a diaphragm.
[0016] FIGS. 6 and 7 show experimental results of an embodiment according to FIG. 5 .
[0017] FIG. 8 denotes a pressure pattern of a cyclic 2-step-depositionprocess.
[0018] FIG. 9 shows a set-up using a throttle valve between a vacuum chamber and a vacuum pump.
[0019] FIG. 10 : Basic set-up for a 2-step process using 2 MFCs (2nd gasline with gas purge) together with applying a throttle valve in front of the vacuum pump.
[0020] FIG. 11 : Basic set-up for a 2-step process using 1 MFC and one gas boost line together with applying a throttle valve in front of the vacuum pump.
[0021] FIG. 12 : Gas rise pattern for the set-up depicted in FIG. 10 .
DETAILED DESCRIPTION OF THE INVENTION
1) Means for Fast Gas Pressure Rising and Stabilization
[0022] a) Gas Purge with Variable Pump Cross Section of the Vent Line
[0023] An embodiment of the invention will be described with the aid of FIG. 3 . The configuration shows an arrangement emanating from FIG. 1 . However, by varying the pump cross section of the vent line 4 (e.g. by means of a needle valve 10 ) it is possible to control the onset of the gas pressure after switching the gas flow from the vent-line 4 into the vacuum chamber 3 (see FIG. 4 )
[0024] If the cross section of the vent line 4 is significantly smaller compared to the gas line into the vacuum chamber 3 this leads to a significantly higher pressure in the vent-line and therefore to a gas pressure peak (“gas overshoot”), if the gas flow is switched into the vacuum chamber 3 (i.e. valve 6 into the vent-line is closed and valve 5 into the vacuum chamber is opened at the same time)
[0025] On the other hand, if the cross section of the vent line 4 is significantly bigger compared to the gas line into the vacuum chamber 3 the smaller pressure in the vent-line 4 leads to a slow increase of gas pressure (“gas undershoot”).
[0026] If appropriate settings for the pump cross section of the vent line are selected the rise of the gas pressure signal can be as short as 0.1 seconds (5 turns of the needle valve in FIG. 4 )
[0027] FIG. 4 shows experimental results from a set-up of FIG. 3 . It is shown the Argon (Ar) gas pressure vs. time for different settings of the needle valve 10 . “Turns” means number of turns CCW; zero corresponds to “needle valve completely closed”); “1 turn” corresponds to the uppermost peak, “2 turns” the second one and so forth. “Gas ON” is represented by the step-like graph. As shown, by varying the cross-section of the vent-line 4 via the needle-valve 10 the gas pressure behavior can be prescribed between gas pressure peak (gas overshoot, e.g. “1 turn”) and slow increase of gas pressure (gas undershoot, e.g. “7 turns”).
b) Gas Boost Using a Combination of a Diaphragm and a Valve
[0028] Very short and reproducible gas pressure pulses can also be realized by the set-up depicted in FIG. 5 .
[0029] A separate gas inlet 13 with variable inlet pressure (e.g. applying a pressure reducing regulator) constantly feeds gas into a volume between a diaphragm 12 (having a very small orifice) and a switchable valve 11 . During normal operation of the gas boost set-up for cyclic processing in a vacuum chamber 3 (e.g. processing of substrates in a vacuum apparatus) this gas volume is then expanded into the vacuum chamber by opening of the valve 11 .
[0030] The aperture of the orifice is chosen such that if the valve 11 was always open the gas flow through the aperture into the vacuum chamber 3 would be negligible (e.g. in the 10 −4 hPa range) compared to the desired process pressure. Thus the gas pressure pattern is virtually independent of the time during which the valve 11 remains open. The only constraint for setting the aperture of the diaphragm 12 is that for the desired cycle time the flow through the aperture has to be high enough to fill the volume in between the aperture of diaphragm 12 and the valve 11 .
[0031] Using this gas boost set-up a very fast increase in gas pressure can be realized where the height of the pressure peak can be varied by adjusting the gas inlet pressure (see Fig.) or changing the size of the gas expansion volume.
[0032] The effect of this gas boost method is similar to the gas expansion method described in Prior Art section 2 ) but applying only one valve is more cost effective. FIG. 6 shows respective results in gas pressure vs. time in an embodiment according to FIG. 5 for different settings of the inlet pressure from gas inlet 13 . “1.0 bar” is represented by the lowest peak, “1.6 bar” by the uppermost peak “Gas ON” is represented by the step-like graph.
[0033] FIG. 7 represents gas pressure vs. time for different pulse length of the “valve open” signal showing that after a specific time needed to empty the expansion volume the gas pattern is independent of the opening time of the valve 11 . In FIG. 7 “20 ms” represents the lowest peak, graphs for 40-160 ms are represented by the overlay of other graphs. Gas ON=step-like graph.
2) 2-Step Processes
[0034] One application for the invention is a 2-step process (second step having a significantly different gas pressure compared to first step) by using
a) a fast throttle valve in front of the vacuum pump which is closed/opened in order to increase/decrease the pressure. b) a throttle valve in combination with adding a second gas (gas purge principle) and/or applying a gas boost for fast pressure increase for the high pressure application.
a) Throttle Valve Operation
[0037] FIG. 8 denotes the pressure pattern of a cyclic 2 step process realized in a setup shown in FIG. 9 : A process chamber 3 using one gas inlet 14 with gas purge and a throttle valve 16 between the vacuum chamber 3 and a vacuum pump 17 : In FIG. 8 section i shows the gas pressure p 1 which is set by the flow set-point of the MFC 2 . At the beginning of section ii the throttle valve 16 is closed which leads to a pressure increase, and, after a time of approx. 1.5 s, to a pressure p 2 which is governed by the MFC flow together with the specific shape of the throttle valve 16 . After section ii the throttle valve 16 is opened again and after a variable time interval (section iii) designated for pump-out the processed substrate is transported into the next chamber whilst a new substrate is brought into the chamber. (Note: In this case the Argon gas flow of the MFC was never turned off since inert gas pressures in the 10 −3 hPa range are tolerable during transport throughout the system.)
[0000] b) Throttle Valve Together with Gas Pulses for Fast Pressure Rise Times
[0038] In order to accelerate the pressure rise time at the beginning of section ii ( FIG. 8 ) an additional second MFC 20 and gas purge set-up (as described in paragraph 1a above) or/and the gas boost set-up (as described in paragraph 1b above) are added to the gas manifold. The respective schematics are shown in FIGS. 10 and 11 . A respective second gas inlet is marked by reference 15 .
[0039] In a further embodiment of the invention, e.g. for the gas purge set-up an optimized gas overshoot setting for gas inlet 15 leads to a quasi instantaneous pressure rise. FIG. 12 shows for the set-up of FIG. 10 the gas pressure behaviour for different applications. “Gas 1 with throttle”, the middle graph shows the effect of the branch connected to gas inlet 14 . “Gas 2 (no throttle)” is the lowest graph and describes the effect of gas inlet 15 without use of the throttle valve 16 . “Gas 1+2 with throttle” describes the effect of using both combined in the uppermost graph.
FURTHER ADVANTAGES OF THE INVENTION
[0040] The gas boost approach is also very well suited as an ignition help for plasma processes (especially RF processes) since it guarantees a very short high pressure pulse which can be set independent of the gas flow used during the process.
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In an apparatus for controlling a gas-rise pattern in a vacuum treatment process a gas inlet ( 1 ) is operatively connected with a mass-flow-controller MFC ( 2 ); said MFC ( 2 ) being again operatively connected via a first valve ( 5 ) with a vacuum chamber ( 3 ) and in parallel via second valve ( 6 ) with a vent-line ( 4 ). Said connection with the vent-line ( 4 ) further comprises means for varying the pump cross section of said vent-line ( 4 ). In another embodiment the apparatus for controlling a gas-rise pattern in a vacuum treatment process comprises a gas inlet ( 13 ) operatively connected with a vacuum chamber ( 3 ) via a valve ( 11 ), wherein the connection between gas inlet ( 13 ) and valve ( 11 ) further comprises a diaphragm ( 12 ).
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FIELD OF THE INVENTION
This invention relates to arrow rest for archery bows, and more particularly to a flipper type arrow rest capable of both horizontal and vertical flexing movement.
THE PRIOR ART
In archery competition, as well as in bow hunting, accurate marksmanship is important and precise control of the various parameters affecting the accuracy of arrow flight is critical. Various mechanical aids have thus been heretofore developed for use by archery marksmen to improve accuracy. One such device is an arrow rest for properly positioning an arrow prior to release from the bow string. Such arrow rest serve to assist in aiming the arrow, but it is important that the rests not interfere with the stabilizing feathers or vanes of the arrow as the arrow passes by the arrow rest.
Several arrow rests have been previously utilized by archers. These prior art rests have often included a ledge or shelf that may be an integral part of the bow or a similarly shaped bracket temporarily or permanently secured to the side of the bow. Other available arrow rests are quite complicated and involve several shafts and separate springs for adjustable positioning of an arrow prior to ejection. Existing arrow rests are usually expensive in cost, difficult to install and often consist of several associated component parts of metal or plastic that affect the balance of the bow and which require frequent replacement. Examples of prior arrow rests are described in U.S. Pat. Nos. 3,865,096 and 3,919,997.
A need has thus arisen for an arrow rest for providing proper positioning of the arrow prior to release from a bow string yet which offers minimum resistance to the arrow stabilizing structure as the arrow transverses the bow. A need has further arisen for an arrow rest which suppresses or compensates for vertical arrow oscillations while also reducing archer's paradox. Such an arrow rest should have a simple contruction to minimize cost and maintenance related problems, while being light in weight as to not affect the balance of the archery bow.
SUMMARY OF THE INVENTION
The present invention is directed to an arrow rest for providing proper positioning of the arrow prior to release from the bow string and for reducing vertical arrow oscillations and archer's paradox, and which substantially eliminates or reduces the disadvantages associated with prior art arrow rests.
In accordance with the present invention, an arrow supporting device is provided for use with an archery bow and arrows having stabilizing structure attached to the rear portion of the arrows. The device includes a mounting member adapted to be affixed to the bow. A closed loop member is provided and is pivotally attached to the mounting member. The closed loop member is biased to extend laterally of the mounting member into an arrow receiving and supporting position to support an arrow in a predetermined angular spaced relationship to the archery bow when the arrow is readied for release. The closed loop member is also retractable towards the mounting member to thereby permit the stabilizing structure of the arrow to clear the arrow supporting device with a minimum of resistance to thereby minimize arrow deflection as the arrow transverses the bow.
In accordance with another aspect of the present invention, an arrow supporting device is provided for use with an archery bow having a plunger device and with arrows having a stabilizing structure attached to the rear portion of the arrows. The arrow supporting device includes a flexible mounting plate which is adapted to be affixed to the bow and which includes an aperture for receiving the plunger device. A closed loop wire is provided with first and second arm members which are independently compressible and expandable. The first and second arm members include first and second ends extending substantially normal to the arm members. First and second cylindrical pivot housings are rigidly affixed to and are laterally offset on the flexible mounting plate for receiving the closed loop wire ends, such that the wire ends are rotatable within the cylindrical pivot housings. The first and second arm members of the closed loop wire lie at a predetermined angular spaced relationship to one another and are capable of being vertically flexed for vertical positioning and for cushioning of an arrow against the cushion plunger device. One of the arm members includes a stop for biasing the closed loop wire to extend laterally of the flexible mounting plate into an arrow receiving and supporting position to support the arrow at a predetermined angular spaced relationship horizontal to the archery box when the arrow is ready for release. The closed loop wire is also horizontally retractable towards the flexible mounting plate as the arrow is released to thereby permit the arrow stabilizing structure to clear the arrow supporting device as the arrow transverses the bow to minimize deflection of the arrow in flight. An adhesive is applied to the flexible mounting plate for affixing the flexible mounting plate to the bow. A removable paper covering is attached to the adhesive for protecting the adhesive prior to affixing the flexible mounting plate to the archery bow.
DESCRIPTION OF THE DRAWINGS
For a more complete understanding of the present invention and for further objects and advantages thereof, reference is now made to the following description taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a side elevation view of a conventional archery bow showing the arrow rest of the present invention;
FIG. 2 is an enlarged fragmentary side elevation view of a portion of the archery bow shown in FIG. 1 illustrating one embodiment of the arrow rest of the present invention;
FIG. 3 is a top plan view of the arrow rest of the present invention shown in FIG. 2 illustrating the closed loop in the lateral extended position;
FIG. 4 is a top plan view of the arrow rest of the present invention shown in FIG. 2 illustrating the closed loop in the retracted position; and
FIG. 5 is a side elevation view of a second embodiment of the arrow rest of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, the arrow rest of the present invention is illustrated and is identified generally by the numeral 10. The arrow rest 10 is attached to the proper location at the spine point of a conventional archery bow identified generally by the numeral 12. The archery bow 12 includes upper and lower limbs 14 and 16 and a handle riser section 18. The archery bow 12 is provided with the usual bow string 20 and a contoured hand grip portion 22 that is located just below the spine-point of the bow 12. It will of course be understood that the arrow rest 10 can also be used on more complex archery bows. FIG. 1 further illustrates a conventional arrow identified generally by the numeral 26 having a shaft 28 and fletchings 30. Fletchings 30 may comprise conventional feathers or plastic vanes, which provide a stabilizing structure for the arrow 26 in flight. The arrow 26 further includes a point 32 and nock 34 for engaging the bow string 20.
Referring simultaneously to FIGS. 2, 3 and 4, wherein like numerals are utilized for like and corresponding parts, the illustrated embodiment of the arrow rest 10 includes a mounting plate 40. Mounting plate 40 includes an aperture 42 for receiving a plunger cushion button 44. The plunger cushion button 44 is part of a conventional plunger device (not shown), which may be installed in the side wall of the handle riser section 18 (FIG. 1) of the bow 12. The mounting plate 40 is preferably fabricated of brass, anodized aluminum or the like to preclude the damaging effects of rust. The mounting plate 40 is positioned such that its longitudinal axis lies parallel to the direction of flight of the arrow 26. This placement of the mounting plate 40 minimizes the resistance offered by the arrow rest 10 to the fletchings 30 as the arrow 26 is shot from the bow 12.
Rigidly affixed to the mounting plate 40 are cylindrical pivot housings 46 and 48. The cylindrical pivot housing 46 and 48 are slightly vertically offset and parallel oriented to one another to receive the ends of a closed loop wire identified generally by the numeral 50. The closed loop wire 50 includes an inner arm member 52 having an end 54 and an outer arm member 56 having an end 58. The ends 54 and 58 of the closed loop wire 50 are received in the cylindrical pivot housings 46 and 48 such that the closed loop wire 50 is pivotally attached to the mounting plate 40. The closed loop wire 50 is capable of movement between an arrow receiving and supporting position shown in FIG. 3 and a retracted position shown in FIG. 4 to allow the fletchings 30 to pass by unimpeded.
The end 58 of the outer arm member 56 extends outwardly and downwardly of the cylindrical pivot housing 48 to contact the surface of the mounting plate 40 when the closed loop wire 50 is in the arrow receiving and supporting position. The arm members 52 and 56 are held in a slightly biased position by the housings 46 and 48 to bias the closed loop wire 50 outwardly of the mounting plate 40 to receive the shaft 28 of arrow 26. The end 58 of outer arm member 56 abuts against the mounting plate 40 to determine the angular position of the closed loop wire 50 when it is in the arrow receiving an supporting position shown in FIG. 3. The position of the end 58, which acts as a stop member, changes the spaced relationship between the closed loop wire 50 and the mounting plate 40 to accommodate different size diameter arrow shafts.
The cylindrical pivot housings 46 and 48 are laterally offset on the mounting plate 40, which together with the angular displacement of the arms 52 and 56, cause the closed loop wire 50 to slant downwardly at a predetermined angle towards the mounting plate 40. This slant between the closed loop wire 50 and the mounting plate 40 causes the arrow to be positioned and cradled against the plunger cushion button 44 to securely position the arrow 26 prior to its release. The positions of the cylindrical pivot housings 46 and 48 are such that they offer a minimum of resistance to the fletchings 30 as the arrow 26 transverses the bow 12.
By maintaining the position of the arrow shaft 28 against the plunger cushion button 44, the closed loop wire 50 tends to compensate for and minimize horizontal arrow bowing and flexing, commonly termed horizontal paradox, associated with the flight of the arrow when released from the tensed bow string 20 (FIG. 1). The resiliency of the closed loop wire 50 also provides a spring effect to cushion and eliminate bounces, or vertical paradox, from the arrow 26 as it transverses the bow 12. As is known, such arrow bouncing can be caused by improperly tillered bows where the top and bottom limbs are misaligned.
Another important aspect of the present invention is that the closed loop wire 50 is self-biased or stressed such that one arm member stretches and the other arm member compresses as the loop wire 50 pivots between the extended position shown in FIG. 3 and the retracted position shown in FIG. 4. The self-biasing of the loop wire 50 causes the loop wire 50 to pivot inwardly to accommodate the arrow flechings, and then to automatically spring back to the outward position shown in FIG. 3. This feature of the closed loop wire 50 eliminates the need of additional separate springs and components to extend the arrow rest after passage of an arrow. As noted, the spring effect of the closed loop wire 50 is created by the initial biasing of the arms 52 and 56 and because the inside arm 52 compresses while the outside arm 56 stretches as the loop wire 50 is moved inwardly by the passage of the arrow.
The closed loop wire 50 is preferably fabricated of light gauge stainless steel wire, which has sufficient horizontal and vertical resiliency and strength to apply the necessary pressure and support to the arrow shaft 28, and which can withstand repeated usage. The closed loop wire 50 may also comprise stainless steel wire coated with graphite, or other suitable materials. Depending upon the archery bow weight, draw length and other bow parameters, the diameter of the closed loop wire 50 may be selected from about 0.025 inches to about 0.032 inches.
Referring to FIG. 3, the mounting plate 40 is provided on its rear surface with a conventional adhesive coating 60 for affixing the arrow rest 10 to the surface of the bow 12. A lightly adhering, removable paper covering 62 is provided to temporarily protect the adhesive 60 prior to affixing the arrow rest 10 to the bow 12. Of course, the plate 40 may also be attached by conventional mounting techniques.
FIG. 5 illustrates a second embodiment of the present invention, identified generally by the numeral 66. Like numerals are utilized in FIG. 5 for like and corresponding parts previously identified. The arrow rest 66 includes a mounting plate 68 including an aperture 42 for receiving a plunger cushion button (not shown). The mounting plate 68 includes two flanges 70 and 72 formed by a stamping operation which each include two apertures for receiving the ends 54 and 58 of the closed loop wire 50. The flanges 70 and 72 function similarly to the housings 46 and 48 previously described in connection with FIGS. 2, 3 and 4.
Although the mounting plates 40 and 68 have been illustrated having a particular configuration, other shapes and configurations may be utilized. The mounting plates 40 and 68 need not include an aperture 42 for those archery bows which do not utilize plunger devices. It will also be understood that the present arrow rest can be manufactured to accommodate both right and left-handed archery bows.
Whereas the present invention has been described with respect to specific embodiments thereof, it will be understood that various changes and modifications will be suggested to one skilled in the art, and it is intended to encompass such changes and modifications as fall within the scope of the appended claims.
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An arrow supporting device for use with an archery bow which includes a mounting plate adapted to be affixed to the archery bow, and a closed loop spring member having two ends pivotally attached at the ends to the mounting plate. The closed loop spring member is biased to extend laterally of the mounting plate in order to support an arrow in a predetermined relationship to the archery bow as the arrow is readied for release. The closed loop spring member is movable towards the mounting plate to permit the stabilizing structure of the arrow to clear the arrow supporting device with a minimum of resistance to minimize arrow deflection. Said loop spring member includes two spaced apart arms.
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STATEMENT OF GOVERNMENT INTEREST
The invention described was made in the performance of official duties by one or more employees of the Department of the Navy, and thus, the invention herein may be manufactured, used or licensed by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.
BACKGROUND
The invention relates generally to tiles for body armor. In particular, the invention relates to interlocking tiles to provide protection from small arms fire with improved flexibility.
During combat and insurgency patrol, military personnel can be subject to small-arms fire from gun-fired projectile rounds, as well as blast and fragmentation from grenades, designed to attack flesh. Personnel struck by such weapons can suffer serious or even mortal injury. To reduce vulnerability to combatants from such lethal contacts, wearable personnel armor, such as a vest with resistant-fiber mesh, has been developed. Further improvements have integrated high strength intermediary materials to further absorb or deflect kinetic impacts. Such measures have added weight and reduced flexibility for personnel so clad.
Conventional tactical body armor within the United States armed forces consists of small arms protective insert (SAPI) and Enhanced SAPI (ESAPI) ceramic trauma plates. The plates vary in performance where the SAPI plates are capable of defeating M80 ball rounds and the ESAPI is capable of defeating 0.30 caliber M2AP rounds. The plates are inserted within an interceptor vest which is capable of stopping 9 mm×19 mm handgun bullets. Conventional ESAPI/SAPI plates are comparatively large and bulky, and additionally limit flexibility of the wearer.
SUMMARY
Conventional body armor yield disadvantages addressed by various exemplary embodiments of the present invention. In particular, various exemplary embodiments provide an angled hexagonal tile (AHT) to incorporate as an interleaving arrayed plurality for a personnel armor clothing article. The plurality for the array is adhered onto a liner substrate. The AHT includes a hexagonally-symmetric solid object composed of a homogeneous material. The object includes a geometry that has obverse and reverse planar surfaces parallel to each other and separated by a thickness. Each planar surface has triangularly disposed terminals. Each obverse terminal is angularly offset to an adjacent reverse terminal.
In exemplary embodiments, the terminals on each corresponding planar surface have a length between a vertex at a first terminal and a center-point between second and third terminals. A first triple set of obverse-facing oblique surfaces is disposed between the obverse and reverse planar surfaces. Each obverse-facing oblique surface connects an obverse center-point on the obverse planar surface and a corresponding reverse terminal on the reverse planar surface. A second triple set of reverse-facing oblique surfaces is disposed between the obverse and reverse planar surfaces.
Each reverse-facing oblique surface connects an obverse terminal on the obverse planar surface and a corresponding reverse center-point on the reverse planar surface. A plurality of facets is disposed substantially perpendicular to the planar surfaces. The facets connect between edges of the planar surfaces and adjacent edges of the oblique surfaces. The first and second triple sets of oblique surfaces are disposed to alternate with each other.
In various embodiments, the object is composed of ceramic. In alternate embodiments, the planar surfaces form a contiguous triangular arrangement of hexagons. In other embodiments, these surfaces form a triangular boundary terminated by elongated octagons.
BRIEF DESCRIPTION OF THE DRAWINGS
These and various other features and aspects of various exemplary embodiments will be readily understood with reference to the following detailed description taken in conjunction with the accompanying drawings, in which like or similar numbers are used throughout, and in which:
FIG. 1 is an isometric view of a first tile configuration;
FIG. 2 is an isometric view of an array of first tiles;
FIG. 3 is an isometric view of a second tile configuration; and
FIG. 4 is an isometric view of an array of second tiles.
DETAILED DESCRIPTION
In the following detailed description of exemplary embodiments of the invention, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific exemplary embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments may be utilized, and logical, mechanical, and other changes may be made without departing from the spirit or scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims.
Exemplary embodiments provide an interlocking tile geometry that improves protection of a surface otherwise vulnerable to kinetic collision, such as from bullet impact. Such tiles can be arranged between substrate layers to provide contiguous yet flexible shock-absorbent material in a wearable clothing article, such as in a jacket to protect the wearer's torso. The layers can represent a variety of woven fabrics, such as aramid Kevlar® and high-modulus polyethylene Spectra®.
The tile design corresponds to a hexagonally symmetric form to represent an angled hexagonal tile (AHT) geometry. The AHTs provide three advantages including: (a) angled interfaces that reduce interstitial vulnerability from conventional tiles, (b) force distribution enhances multi-impact capability by reduced damage propagation, and (c) adhesion to one surface of the AHTs to a flexible fabric facilitates flexibility with an integrated and contiguous area of body protection from blunt force trauma.
FIG. 1 shows an isometric view 100 of a first tile configuration 110 for an AFT. A compass rose 115 shows Cartesian orientation of the first AHT 110 with x and z directions representing the facial x-z plane parallel to the surface to be shielded, and y direction denoting thickness. View 100 shows an obverse planar surface 120 (normal upward relative to y) parallel to a reverse planar surface 125 (normal downward relative to y). These planar surfaces 120 and 125 reveal a contiguous regular tri-hexagonal form.
Triple upward-facing oblique rectangular wedges 130 concatenate alternatingly with counterpart triple downward-facing oblique rectangular wedges 135 . Obverse-adjacent triangular edge facets 140 , 145 , 150 and 155 interweave the wedges 130 and 135 with the obverse surface 120 . Similarly, reverse-adjacent triangular edge facets 160 , 165 , 170 and 175 interweave the wedges 130 and 135 with the reverse surface 125 . These triangular facets are substantially perpendicular to the planar surfaces 120 and 125 and thereby at least approximately parallel to y. The planar surfaces 120 and 125 feature three outward obtuse tips 180 flanked by six adjacent obtuse vertices 185 , such that three inverse divots 190 are disposed therebetween. Effectively, tips 180 and the divots 190 yield overlapping triangles that form a Star-of-David on the planar surface 120 .
Thickness of the tile 110 between the planar surfaces 120 and 125 is denoted as height H and for exemplary personnel armor can vary based on threat assessments. Expected thickness range between ¼ inch and ⅝ inch. The example height illustrated in view 100 constitutes 0.50 inch (1.27 cm). Distance along the obverse surface 120 between a first tip 180 and its opposite divot 190 on the obverse surface 120 is denoted as length L, which for exemplary personnel armor can vary between one inch and five inches, depending on requirements. The example length in view 100 measures 1.25 inch (3.175 cm).
The interface angle θ between the divot 190 on the obverse surface 120 and the adjacent tip 180 on the reverse surface 125 can vary from ten degrees to sixty degrees. The example angle in view 100 is 50.19442891° (0.87606 radian). The tips 180 on the obverse surface 120 and the tips 180 on the reverse surface 125 are angularly offset. In the configuration shown, this phase offset is 180° (π radians) between the corresponding obverse and reverse tips 180 .
FIG. 2 shows an isometric view 200 of an array 210 of the first AHTs 110 connected together by interleaving facets. The obverse surfaces 120 and select wedges 130 and 135 along the edge are illustrated. Of the seven tiles 110 depicted, the fore unit 220 presents one tip 180 facing right, with aft unit 230 , starboard unit 240 and port unit 250 sharing edges, along with a rear unit 260 behind the port unit 250 . Edge transitions along the obverse surfaces 120 include corners at tip-to-divot 270 , vertex-to-divot 275 , and vertices junction 280 . Fore and aft units 220 and 230 connect with the tip-to-divot 270 .
Fore and port units 220 and 250 connect with the tip-to-divot 275 . At their adjacent vertices 185 , the port, aft and rear units 230 , 250 and 260 connect together at their common junction 280 . Similarly, complementary wedges 130 and 135 on adjacent tiles 110 face each other, as do triangular facets 140 with complements 150 , along with facets 145 with 155 , facets 160 with 170 and facets 165 with 175 .
FIG. 3 shows an isometric view 300 of a second tile configuration 310 for the AHT. A compass rose 315 shows orientation of the second AHT 310 similarly as rose 115 . View 300 shows an obverse planar surface 320 (normal upward relative to y) parallel to a reverse planar surface 325 (normal downward relative to y). These planar surfaces 320 and 325 reveal a contiguous triple elongated-octagon form. Triple upward-facing oblique rectangular wedges 330 concatenate alternatingly with counterpart triple downward-facing oblique rectangular wedges 335 .
Obverse-adjacent triangular edge facets 340 , 345 , 350 and 355 interweave the wedges 330 and 335 with the obverse surface 320 . Similarly, reverse-adjacent triangular edge facets 360 , 365 , 370 and 375 interweave the wedges 330 and 335 with the reverse surface 325 . These obverse-adjacent and reverse-adjacent triangular facets are substantially parallel to y, and join at the intersections with their associated wedges 330 and 335 . The planar surfaces 320 and 325 feature three outward edges 380 joined at chamfered sides of the facets by three inward edges 390 . Effectively, centers of the outward edges 380 and the inward edges 390 yield overlapping triangles that form a Star-of-David on the planar surface 320 .
FIG. 4 shows an isometric view 400 of an array 410 of the second AHTs 310 . A compass rose 415 shows orientation of the assembly 410 with normal to the planar surfaces 320 parallel to the y-direction. The identified tiles 310 include left upper unit 420 , right upper unit 430 , center unit 440 and right lower unit 450 . Edges of units 430 , 440 and 450 join together at a junction point 460 between the edges 380 and 390 .
Arrays 210 and 410 enable force absorption from kinetic impact onto obverse surfaces 120 and 320 by momentary flexing, coupled with the plastic deformation of individual tiles 110 and 310 . In particular, flexing constitutes angular separation of the respective constituent tiles 110 and 310 from their neighbors. For example for view 200 , striking the aft unit 230 causes its downward deflection in the −y direction (see rose 115 ). The adjacent units, including 220 , 250 and 260 , are constrained laterally by their substrate layers (not shown), and thus deflect by tilting, while maintaining protection against subsequent impacts without serious gaps.
Type of AHT deformation depends on composition material. The AHT can be considered to be a homogeneous substantially isotropic material. Ceramic units, such as boron carbide (B 4 C) and silicon carbide (SiC), can fracture under high compressive and shear loads. Ceramic material can also include boron carbide derivatives, such as boron carbide nitride, poly(6-cyclooctenyldecaborane) and poly(6-norbornenyldecaborane). Other more ductile materials (e.g., metals) can plastically deform without shattering, but at lower yield strengths than typical for ceramics.
To enable the development of flexible body armor that reduces blunt force trauma from a projectile strike, reduces vulnerabilities from interstitial joints, benefits from decreased weight, and increases multi-hit capability over conventional designs. The force from bullet impact against an angled hexagonal tile matrix is distributed across multiple tiles while still enabling each individual tile to flex. In addition, the angled sides reduce the vulnerabilities of the joining seams, where the angled joints can either deflect or dissipate incident threats.
Based on desire to reduce weight, increase multi-hit capability, and enhance flexibility, the AHT has been designed to satisfy these requirements. The first AHT design modifies geometry relative to the second AHT design, thereby simplifying the production, lowering the cost, and minimizing the number of interface surfaces to improve the transmission of shock waves across each other, instead of the wearer.
The AHT objects can replace the conventional SAPI/ESAPI plates with the ceramic AHTs, forming equivalent surface area coverage but with fewer gaps for improved bodily protection. Preferably, the ceramic materials are composed of either boron carbide or silicon carbide, and can be manufactured to near theoretical maximum density to provide optimal material properties. Alternative ceramics can be used, including compositions that derive from boron carbide.
The ceramic AHT units are joined together in an array and adhered to a spall liner fabric substrate. After adhesion to the liner, the AHTs 110 and/or 310 can optionally be encapsulated within polyurea foam. This technique is described in U.S. Patent Application Publication 2012/0312150, incorporated by reference in its entirety.
The exemplary AHTs can be integrated into the body armor system similar to the current SAPI/ESAPI plates as inserts. For each exemplary first AHT 110 , the six peripheral faces 130 and 135 are angularly disposed in relation to the nominal hexagonal orientation, with each AHT 110 having three positively angled wedges 130 and three negatively angled wedges 135 alternating symmetrically back and forth along the periphery.
The adherence of the reverse surface 125 to the spall liner inhibits lateral tile movement. In response to kinetic impact, the AHTs 110 direct force on each neighboring tile through the angled wedges 130 and 135 , enabling the impact energy to be distributed across all of the AHTs 110 . The angled wedges also reduce the interstitial vulnerability at seams between tiles 110 by eliminating straight-through points. This similarly applies to the second AHT 310 .
While certain features of the embodiments of the invention have been illustrated as described herein, many modifications, substitutions, changes and equivalents will now occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the embodiments.
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An interleaving hexagonal tile (AHT) is provided for incorporation onto a liner in an array for a personnel armor clothing article. The AHT includes a hexagonally-symmetric solid object composed of a homogeneous material. The object includes a geometry that has obverse and reverse planar surfaces parallel to each other. Each planar surface has triangularly disposed terminals. First and second triple sets of oblique surfaces are disposed between the obverse and reverse planar surfaces. A plurality of facets is disposed substantially perpendicular to the planar surfaces. The facets connect between edges of the planar surfaces and adjacent edges of the oblique surfaces. The first and second triple sets of oblique surfaces are disposed to alternate with each other.
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BACKGROUND
The present disclosure relates, in various exemplary embodiments, to high temperature applications for bichromal balls and related signage or displays utilizing the same. The disclosure finds particular application in conjunction with reusable display technology and “electric paper,” which is electronically writeable and erasable and will be described with particular reference thereto. However, it is to be appreciated that the present exemplary embodiments are amenable to other like applications.
Bichromal balls, or beads as sometimes referred to in the art, are tiny spherical balls, such as micron-sized wax beads, which have an optical and an electrical anisotropy. These characteristics generally result from each hemisphere surface or side having a different color, such as black on one side and white on the other, and electrical charge, i.e., positive or negative. Depending on the electrical field produced, the orientation of these beads will change, showing a different color (such as black or white) and collectively create a visual image.
In this regard, the spherical particles are generally embedded in a solid substrate with a slight space between each ball. The substrate is then filled with a liquid (such as an oil) so that the balls are free to rotate in a changing electrical field, but can not migrate from one location to another. If one hemisphere is black and the other is white. Each pixel can be turned on and off by the electrical field applied to that location. Furthermore, each pixel can be individually addressed, and a full page image can thus be generated.
For example, reusable signage or displays can be produced by incorporating the tiny bichromal beads in a substrate such as sandwiched between thin sheets of a flexible elastomer and suspended in an emulsion. The beads reside in their own cavities within the flexible sheets of material. Under the influence of a voltage applied to the surface, the beads will rotate to present one side or the other to the viewer to create an image. The image stays in place until a new voltage pattern is applied using software, which erases the previous image and generates a new one. This results in a reusable signage or display that is electronically writable and erasable.
Furthermore, electronic displays produced by these bichromal balls or beads are sometimes referred to as “gyricon” displays. This terminology is reportedly the result of a combination of the Greek word for “rotating” and the Latin word for “image.”
Numerous patents describe bichromal balls, their manufacture, incorporation in display systems or substrates, and related uses and applications. Exemplary patents include, but are not limited to: U.S. Pat. Nos. 5,262,098; 5,344,594; 5,604,027 reissued as Re 37,085; 5,708,525; 5,717,514; 5,739,801; 5,754,332; 5,815,306; 5,900,192; 5,976,428; 6,054,071; 5,989,629; 6,235,395; 6,419,982; 6,235,395; 6,419,982; 6,445,490; and 6,703,074; all of which are hereby incorporated by reference. In addition, disclosure is provided by U.S. Pat. Nos. 4,126,854; and 5,825,529; and N. K. Sheridon et al., “The Gyricon—A twisting ball display”, Proc. SID, Boston, Mass., 289, 1977; T. Pham et al., “Electro-optical characteristics of the Gyricon display”, SID '02 Digest, 199, 2002; which again are hereby incorporated by reference.
Gyricon displays, or those based upon bichromal balls, are mainly used for indoor electronic signage applications. Outdoor applications are limited because the base polymer used in Gyricon media is a nonfunctional polyethylene, such as POLYWAX® 1000 or POLYWAX® 2000 from Baker Petrolite Corporation, Sugarland, Tex. The reason for the limited application is that at higher temperatures, it is believed that a fraction of the POLYWAX® leaches out to silicone fluid typically utilized inside the device, such as at about 50° C. to about 60° C. These unwanted materials are then carried or dispersed in the silicone fluid, thereby hindering bead rotation. As a result, the optical performances of the devices are significantly reduced. At present, the application temperature must generally be maintained below about 40° C. by various cooling methods and there is no very successful method to prevent the noted leaching difficulties described generally above.
Accordingly, there is a need for a bichromal ball display and related techniques for producing the same, that can be used at relatively high temperatures, and which avoids the problems associated with currently known displays.
BRIEF DESCRIPTION
In accordance with one aspect of the present disclosure, a process is provided for forming bichromal balls adapted for use in high temperature applications. The process comprises providing a polyalkylene wax and an organic solvent, and extracting the polyalkylene wax with the organic solvent to yield a purified polyalkylene wax. The process further comprises forming bichromal balls from the purified polyalkylene wax, to thereby produce the bichromal balls adapted for use in high temperature applications.
In yet another aspect, the disclosure provides a process for forming bichromal balls adapted for display applications for use at temperatures greater than 40° C. The process comprises providing a polyalkylene wax, such as a polyethylene wax, and an organic solvent, such as an isoparaffin solvent, and extracting the wax with the solvent at a temperature greater than about 60° C., preferably greater than about 80° C., to remove a fraction of the wax from a remaining purified portion of the wax. The fraction has an average molecular weight less than the average molecular weight of the purified portion of the wax. The process also comprises forming bichromal balls adapted for display applications at temperatures greater than 40° C. from the purified portion of the wax.
These and other non-limiting aspects and/or objects of the exemplary embodiments are more particularly disclosed below.
BRIEF DESCRIPTION OF THE DRAWINGS
The following is a brief description of the drawings, which are presented for the purposes of illustrating one or more of the exemplary embodiments disclosed herein and not for the purposes of limiting the same.
FIG. 1 is a graph of heat flow as a function of temperature for a polyalkylene wax undergoing an extraction operation as described herein; and
FIG. 2 is a graph of heat flow as a function of temperature for another polyalkylene wax undergoing an extraction operation as described herein.
DETAILED DESCRIPTION
The present disclosure provides, in various exemplary embodiments, the processes and procedures for purifying a polyalkylene wax, and particularly a polyethylene wax, by solvent extraction. The purified polyalkylene wax is then incorporated into bichromal balls or beads to produce a bichromal ball display. The resulting displays are suitable for use in high temperature applications.
In this regard, a polyalkylene wax, such as a blend of polyethylene waxes having different molecular weights, is suspended in a hot (i.e., from about 60° C. to about 100° C., and generally at about 80° C.) organic solvent, such as an isoparaffin solvent, for several hours (i.e., from about 1 hour to about 12 hours), followed by a hot extraction and/or filtration. This procedure may be repeated one or more times. The extracted materials are identified as low molecular weight waxes (i.e., from about 300 to about 700 molecular weight polyalkylenes) by DSC. The remaining purified waxy solids can then be mixed with pigment and utilized for producing bichromal balls or beads. Pigmented wax beads or bichromal balls as generally referred to herein, made of purified polyalkylene wax (i.e., molecular weights from about 700 to about 3,000, including greater than about 1,000 molecular weight), have shown superior tolerance towards leaching in silicone oil at elevated temperatures.
As briefly mentioned above, the base polymer typically used in the production of Gyricon beads or bichromal balls is a crystalline polyethylene wax commercially available under the designation POLYWAX® 1000 (also designated as PW1000) from Baker Petrolite, Corp. The bichromal balls are typically embedded in a layer of a polydimethylsiloxane (PDMS) elastomer which is swollen by Dow Corning DC200 silicone fluid when incorporated into a display device or application. The performance of the resulting device is very good at ambient temperature. However, once the devices are heated beyond about 50° C. and then brought back to room temperature, the device performance is significantly reduced.
In accordance with the present exemplary embodiment, the cause of the above described diminished performance has been identified as resulting from a fraction of polyethylene wax dissolving into the silicone fluid inside the device at high temperatures. After cooling to room or ambient temperature, these leached materials are deposited back inside the device, which hinders the rotation of the bichromal balls.
Currently, no successful method to solve the above described problem is believed to be known. Accordingly, current Gyricon devices should be operated below 40° C. because polyethylene waxes such as PW1000 are highly soluble in DC200 silicone fluid at elevated temperatures.
Additionally, POLYWAX® 2000 (PW2000) is also a polyethylene wax made by Baker Petrolite. This material has also been used for producing bichromal balls because it has a higher melting point than PW1000 (126° C. vs 113° C.) and it is a good candidate for high temperature package. However, bichromal balls made of PW2000 did not show any improvements when utilized in devices at elevated temperatures. Further investigation revealed that even though the leaching of PW2000 is less than PW1000 under identical conditions, the relatively small amount of leached materials is still sufficient to hinder rotation of the bichromal balls.
The present disclosure concerns the use of solvent extraction to remove the soluble fraction of a polyalkylene wax used in the production of bichromal balls, such as for example PW2000. In the embodiments described herein, extraction is performed with a commercially available organic solvent, such as an isoparaffinic solution or solvent designated as ISOPAR®. The purified PW2000 has a superior tolerance to leaching than PW2000 prior to undergoing solvent extraction. Although not wishing to be bound to any particular theory, it is believed that upon extraction, the extracted portion of the wax has an average molecular weight that is less than the average molecular weight of the remaining portion of the wax.
The extraction operation may use a number of solvent extraction steps. That is, the number of extractions can range from about 1 to about 10 times; however, a number from 1 to 5 is typical. It may in certain applications be desirable to perform the extraction at elevated temperatures, such as for example at about 60° C. to about 100° C., and generally at about 800° C.
In addition, the present discovery relates to a process of making high temperature bichromal ball devices from a purified polyalkylene wax such as purified PW2000. That is, the bichromal ball is made of a ‘purified’ PW2000, for example. The purification process is a hot solvent extraction of virgin PW2000 by ISOPAR® C. at 85° C. The low molecular weight fraction of PW2000 is successfully removed. Bichromal ball devices of ‘purified’ PW2000 do not show optical degradation at 78° C. for time periods of over 120 hours.
In this regard, polyalkylene waxes, such as POLYWAX® 1000 and 2000, are generally low molecular weight homopolymers, which are 100% linear and saturated and characterized by a molecular weight distribution (Mw/Mn) of approximately 1.1. Because the POLYWAX polyethylenes are linear and have a narrow molecular weight distribution (MWD), physical properties are highly co-related, such that the melting point and hardness are reportedly controlled by molecular weight alone.
The production process of such waxes is controllable to the extent that desired molecular weight products are obtained predictably and consistently. Product with number average molecular weights from about 450 to about 3000, with corresponding melting points of 80° C. to 132° C., are commercially available. Due to their 100% linearity and narrow molecular weight distribution, POLYWAX® polyethylenes characteristically display high crystallinity and sharp melting points.
Typical properties of polyethylene waxes such as POLYWAX® 1000 are POLYWAX® 2000 and as follows:
Molecular
Viscosity(cps)
Melting
Weight
Density(g/cc)
at 149 C.
point/C.
POLYWAX 1000
1000
0.96
15
113
POLYWAX 2000
2000
0.97
50
126
Other commercially available polyalkylenes include the Licowax™ product line available from Clariant, Luwax (BASF), and A-C Wax (Honeywell). Typical properties of these waxes are listed below:
Melting point/C.
Clariant Licowax PE 130
125
Clariant Licowax PE 190
135
Clariant Licowax PE 520
120
Honeywell A-C 810A
121
Honeywell A-C 820A
126
BASF Luwax AH6
112
BASF Luwax AL61
113
In turn, the polyalkylene waxes are purified by hot extraction and/or filtration in organic solvent solutions, such as isoparaffin solutions. ISOPAR® is the brand name for various grades of high-purity isoparaffinic solvents with narrow boiling ranges, available from Exxon Corp. The exceptional purity of ISOPAR® is the basis for such desirable properties such as low odor, selective solvency, good oxidation stability, low electrical conductivity, and low skin irritation. The inherently low surface tension of ISOPAR® also imparts superior spreadability to formulations utilizing ISOPAR®. Other commercially available sources of isoparaffinic solvents can be used such as Ashpar from Ashland Chemical, Soltrol from CPChem, Shellsol (Shell Chemical).
Tables 1-8, set forth below, list various properties for the ISOPAR® grades.
TABLE 1
ISOPAR ® C
Solvency
Kauri-butanol value, ASTM D 1133
27
Aniline Point, ° C.(° F.)
78(173)
Volatility
Flash Point, ASTM D 56, TCC, ° C.(° F.)
−8(18)
Distillation, ASTM D 86, IBP ° C.(° F.)
98(208)
Distillation, ASTM D 86, Dry Point ° C.(° F.)
104(219)
Specific Gravity, @ 15.6° C.(60° F.), ASTM D 1250
0.70
Composition
Saturates
100
Aromatics
<0.01
Purity, ppm
Acids
None
Chlorides
<3
Nitrogen
—
Peroxides
0
Sulfur
1
Surface Properties
Surface tension, dynes/cm @ 25° C.(77° F.), ASTM D 971
20.3
Interfacial tension, @ 25° C.(77° F.)
48.9
Demulsibility
Excellent
TABLE 2
ISOPAR ® E
Solvency
Kauri-butanol value, ASTM D 1133
29
Aniline Point, ° C.(° F.)
75(167)
Volatility
Flash Point, ASTM D 56, TCC, ° C.(° F.)
7(45)
Distillation, ASTM D 86, IBP ° C.(° F.)
118(244)
Distillation, ASTM D 86, Dry Point ° C.(° F.)
137(279)
Specific Gravity, @ 15.6° C.(60° F.), ASTM D 1250
0.72
Composition
Saturates
100
Aromatics
<0.01
Purity, ppm
Acids
None
Chlorides
<2
Nitrogen
<2
Peroxides
0
Sulfur
1
Surface Properties
Surface tension, dynes/cm @ 25° C.(77° F.), ASTM D 971
22.1
Interfacial tension, @ 25° C.(77° F.)
48.9
Demulsibility
Excellent
TABLE 3
ISOPAR ® G
Solvency
Kauri-butanol value, ASTM D 1133
27
Aniline Point, ° C.(° F.)
83(181)
Volatility
Flash Point, ASTM D 56, TCC, ° C.(° F.)
41(106)
Distillation, ASTM D 86, IBP ° C.(° F.)
160(320)
Distillation, ASTM D 86, Dry Point ° C.(° F.)
176(349)
Specific Gravity, @ 15.6° C.(60° F.), ASTM D 1250
0.75
Composition
Saturates
100
Aromatics
<0.01
Purity, ppm
Acids
None
Chlorides
<1
Nitrogen
<1
Peroxides
Trace
Sulfur
1
Surface Properties
Surface tension, dynes/cm @ 25° C.(77° F.), ASTM D 971
23.8
Interfacial tension, @ 25° C.(77° F.)
51.6
Demulsibility
Excellent
TABLE 4
ISOPAR ® H
Solvency
Kauri-butanol value, ASTM D 1133
26
Aniline Point, ° C.(° F.)
84(183)
Volatility
Flash Point, ASTM D 56, TCC, ° C.(° F.)
54(129)
Distillation, ASTM D 86, IBP ° C.(° F.)
178(352)
Distillation, ASTM D 86, Dry Point ° C.(° F.)
188(370)
Specific Gravity, @ 15.6° C.(60° F.), ASTM D 1250
0.76
Composition
Saturates
100
Aromatics
<0.01
Purity, ppm
Acids
None
Chlorides
<3
Nitrogen
<1
Peroxides
<1
Sulfur
1
Surface Properties
Surface tension, dynes/cm @ 25° C.(77° F.), ASTM D 971
24.1
Interfacial tension, @ 25° C.(77° F.)
51.4
Demulsibility
Excellent
TABLE 5
ISOPAR ® K
Solvency
Kauri-butanol value, ASTM D 1133
27
Aniline Point, ° C.(° F.)
83(181)
Volatility
Flash Point, ASTM D 56, TCC, ° C.(° F.)
57(135)
Distillation, ASTM D 86, IBP ° C.(° F.)
178(351)
Distillation, ASTM D 86, Dry Point ° C.(° F.)
197(387)
Specific Gravity, @ 15.6° C.(60° F.), ASTM D 1250
0.76
Composition
Saturates
99.9
Aromatics
<0.01
Purity, ppm
Acids
None
Chlorides
2
Nitrogen
<1
Peroxides
<1
Sulfur
<2
Surface Properties
Surface tension, dynes/cm @ 25° C.(77° F.), ASTM D 971
24.2
Interfacial tension, @ 25° C.(77° F.)
50.1
Demulsibility
Excellent
TABLE 6
ISOPAR ® L
Solvency
Kauri-butanol value, ASTM D 1133
27
Aniline Point, ° C.(° F.)
85(185)
Volatility
Flash Point, ASTM D 56, TCC, ° C.(° F.)
64(147)
Distillation, ASTM D 86, IBP ° C.(° F.)
189(372)
Distillation, ASTM D 86, Dry Point ° C.(° F.)
207(405)
Specific Gravity, @ 15.6° C.(60° F.), ASTM D 1250
0.77
Composition
Saturates
99.9
Aromatics
<0.01
Purity, ppm
Acids
None
Chlorides
<1
Nitrogen
<1
Peroxides
<1
Sulfur
<2
Surface Properties
Surface tension, dynes/cm @ 25° C.(77° F.), ASTM D 971
25.1
Interfacial tension, @ 25° C.(77° F.)
49.8
Demulsibility
Excellent
TABLE 7
ISOPAR ® M
Solvency
Kauri-butanol value, ASTM D 1133
25
Aniline Point, ° C.(° F.)
91(196)
Volatility
Flash Point, ASTM D 56, TCC, ° C.(° F.)
93(199)
Distillation, ASTM D 86, IBP ° C.(° F.)
223(433)
Distillation, ASTM D 86, Dry Point ° C.(° F.)
254(489)
Specific Gravity, @ 15.6° C.(60° F.), ASTM D 1250
0.79
Composition
Saturates
99.9
Aromatics
<0.05
Purity, ppm
Acids
None
Chlorides
—
Nitrogen
—
Peroxides
<1
Sulfur
<2
Surface Properties
Surface tension, dynes/cm @ 25° C.(77° F.), ASTM D 971
26.4
Interfacial tension, @ 25° C.(77° F.)
52.2
Demulsibility
Excellent
TABLE 8
ISOPAR ® V
Solvency
Kauri-butanol value, ASTM D 1133
23
Aniline Point, ° C.(° F.)
92(198)
Volatility
Flash Point, ASTM D 56, TCC, ° C.(° F.)
129(265)
Distillation, ASTM D 86, IBP ° C.(° F.)
273(523)
Distillation, ASTM D 86, Dry Point ° C.(° F.)
312(594)
Specific Gravity, @ 15.6° C.(60° F.), ASTM D 1250
0.83
Composition
Saturates
99.8
Aromatics
<0.05
Purity, ppm
Acids
None
Chlorides
7
Nitrogen
—
Peroxides
<1
Sulfur
1
Surface Properties
Surface tension, dynes/cm @ 25° C.(77° F.), ASTM D 971
26.9
Interfacial tension, @ 25° C.(77° F.)
44.9
Demulsibility
Excellent
Other suitable organic solvents include halogenated hydrocarbons such as 1,3-dichlorobenzene (Aldrich), 1,2,4-trichlorobenzene (Aldrich), halocarbon 0.8 (Halocarbon Inc.), halocarbon 1.8 (Halocarbon Inc.), aromatic hydrocarbons such as toluene (Aldrich), xylene (Aldrich) and linear or branched hydrocarbons with carbon number from 8 to 20.
The purified polyalkylene wax, and particularly polyethylene wax, can be used in a bichromal ball production process. The resulting bichromal balls produced therefrom are particularly adapted for use in high temperature applications.
A typical process for forming the bichromal balls described herein is as follows. After purification, the purified polyalkylene wax is mixed with a first pigment to produce a first wax material. The purified polyalkylene wax is mixed with a second pigment to produce a second wax material. These mixing operations can be performed to produce many different wax materials, typically having different colors or other different properties as compared to the other materials.
Next, the wax materials prepared are then heated to a temperature greater than the highest melting temperature of the wax materials. The heating operations can be performed separately upon each of the wax materials or collectively. Upon the wax materials being heated to a suitable temperature such that the wax material flows, the materials are then deposited onto a spinning disk to produce bichromal balls adapted for use in high temperature applications. The spinning disk production method is described in one or more of the patents referenced herein.
The polymer or wax materials can be colored through the addition of pigments, dyes, light reflective or light blocking particles, etc., as it is commonly known in the art. In this regard, a “pigment” is defined herein to include any substance, usually in the form of a dry powder, which imparts color to another substance or mixture. Most pigments are insoluble in organic solvents and water; exceptions are the natural organic pigments, such as chlorophyll, which are generally organosoluble. To qualify as a pigment, a material must have positive colorant value. This definition excludes whiting, barytes, clays, and talc.
Pigments may be classified as follows:
I. Inorganic
(a) metallic oxides (iron, titanium, zinc, cobalt, chromium). (b) metal powder suspensions (gold, aluminum). (c) earth colors (siennas, ochers, umbers). (d) lead chromates. (e) carbon black.
II. Organic
(a) animal (rhodopsin, melanin). (b) vegetable (chlorophyll, xantrophyll, indigo, flavone, carotene).
Some pigments (zinc oxide, carbon black) are also reinforcing agents, but the two terms are not synonymous; in the parlance of the paint and rubber industries these distinctions are not always observed.
“Dyes” include natural and synthetic dyes. A natural dye is an organic colorant obtained from an animal or plant source. Among the best-known are madder, cochineal, logwood, and indigo. The distinction between natural dyes and natural pigments is often arbitrary.
A synthetic dye is an organic colorant derived from coal-tar- and petroleum-based intermediates and applied by a variety of methods to impart bright, permanent colors to textile fibers. Some dyes, call “fugitive,” are unstable to sunlight, heat, and acids or bases; others, called “fast,” are not. Direct (or substantive) dyes can be used effectively without “assistants”; indirect dyes require either chemical reduction (vat type) or a third substance (mordant), usually a metal salt or tannic acid, to bind the dye to the fiber.
A “colorant” as used herein is any substance that imparts color to another material or mixture. Colorants are either dyes or pigments, and may either be (1) naturally present in a material, (2) admixed with it mechanically, or (3) applied to it in a solution.
There may be no generally accepted distinction between dyes and pigments. Some have proposed one on the basis of solubility, or of physical form and method of application. Most pigments, so called, are insoluble, inorganic powders, the coloring effect being a result of their dispersion in a solid or liquid medium. Most dyes, on the other hand, are soluble synthetic organic products which are chemically bound to and actually become part of the applied material. Organic dyes are usually brighter and more varied than pigments, but tend to be less stable to heat, sunlight, and chemical effects. The term colorant applies to black and white as well as to actual colors.
Examples of such colorants (i.e., pigments, dyes, etc.) and their commercial sources include, but are not limited to, magenta pigments such as 2,9-dimethyl-substituted quinacridone and anthraquinone dye, identified in the color index as C1 60710, C1 Dispersed Red 15, a diazo dye identified in the color index as C1 26050, C1 Solvent Red 19, and the like; cyan pigments including copper tetra-4-(octadecylsulfonamido) phthalocyanine, copper phthalocyanine pigment, listed in the color index as C1 74160, Pigment Blue, and Anthradanthrene Blue, identified in the color index as C1 69810, Special Blue X-2137, and the like; yellow pigments including diarylide yellow 3,3-dichlorobenzidine acetoacetanilides, a monoazo pigment identified in the color index as C1 12700, C1 Solvent Yellow 16, a nitrophenyl amine sulfonamide identified in the color index as Foron Yellow SE/GLN, C1 Dispersed Yellow 33, 2,5-dimethoxy acetoacetanilide, Permanent Yellow FGL, and the like. Other suitable colorants include Normandy Magenta RD-2400 (Paul Uhlich), Paliogen Violet 5100 (BASF), Paliogen Violet 5890 (BASF), Permanent Violet VT2645 (Paul Uhlich), Heliogen Green L8730 (BASF), Argyle Green XP-111-S (Paul Uhlich), Brilliant Green Toner GR 0991 (Paul Uhlich), Heliogen Blue L6900, L7020 (BASF), Heliogen Blue D6840, D7080 (BASF), Sudan Blue OS (BASF), PV Fast Blue B2G0 (American Hoechst), Irgalite Blue BCA (Ciba-Geigy), Paliogen Blue 6470 (BASF), Sudan III (Matheson, Coleman, Bell), Sudan II (Matheson, Coleman, Bell), Sudan IV (Matheson, Coleman, Bell), Sudan Orange G (Aldrich, Sudan Orange 220 (BASF), Paliogen Orange 3040 (BASF), Ortho Orange OR 2673 (Paul Uhlich), Paliogen Yellow 152, 1560 (BASF), Lithol Fast Yellow 0991K (BASF), Paliotol Yellow 1840 (BASF), Novoperm Yellow FG1 (Hoechst), Permanent Yellow YE 0305 (Paul Uhlich), Lumogen Yellow D0790 (BASF), Suco-Gelb L1250 (BASF), Suco-Yellow D1355 (BASF), Hostaperm Pink E (American Hoechst), Fanal Pink D4830 (BASF), Cinquasia Magenta (DuPont), Lithol Scarlet D3700 (BASF), Tolidine Red (Aldrich), Scarlet for Thermoplast NSD PS PA (Ugine Kuhlmann of Canada), E.D. Toluidine Red (Aldrich), Lithol Rubine Toner (Paul Uhlich), Lithol Scarlet 4440 (BASF), Bon Red C (Dominion Color Co.), Royal Brilliant Red RD-8192 (Paul Uhlich), Oracet Pink RF (Ciba-Geigy), Paliogen Red 3871 K (BASF), Paliogen Red 3340 (BASF), and Lithol Fast Scarlet L4300 (BASF). Examples of black pigments include carbon black products from Cabot corporation, such as Black Pearls 2000, Black Pearls 1400, Black Pearls 1300, Black Pearls 1100, Black Pearls 1000, Black Pearls 900, Black Pearls 880, Black Pearls 800, Black Pearls 700, Black Pearls 570, Black Pearls 520, Black Pearls 490, Black Pearls 480, Black Pearls 470, Black Pearls 460, Black Pearls 450, Black Pearls 430, Black Pearls 420, Black Pearls 410, Black Pearls 280, Black Pearls 170, Black Pearls 160, Black Pearls 130, Black Pearls 120, Black Pearls L; Vulcan XC72, Vulcan PA90, Vulcan 9A32, , Regal 660, Regal 400, Regal 330, Regal 350, Regal 250, Regal 991, Elftex pellets 115, Mogul L.
Carbon black products from Degussa-Hüis such as FW1, Nipex 150, Printex 95, SB4, SB5, SB100, SB250, SB350, SB550; Carbon black products from Columbian such as Raven 5750; Carbon black products from Mitsubishi Chemical such as #25, #25B, #44, and MA-100-S can also be utilized.
Other black pigments that may also be used include Ferro™ 6330, a manganese ferrite pigment available from Ferro Corporation, and Paliotol Black 0080 (Aniline Black) available from BASF.
Moreover, one or more processing aid, such as surface active agents and dispersants aids like Aerosol™ OT-100 (from American Cynamid Co. of Wayne, N.J.) and aluminum octoate (Witco). Dispersant aids such as X-5175 (from Baker-Petrolite Corporation), Unithox™ 480 (from Baker-Petrolite Corp.), Polyox™ N80 (Dow), and Ceramer™ 5750 (Baker-Petrolite Corp.) can also be added to the waxy base material.
Once the high temperature bichromal balls are produced by the process set forth above, they may be encapsulated for use in high temperature display applications. Generally, the encapsulation process involves providing a silicone oil which as previously noted can be polydimethylsiloxane. A shell material as described in the art is also provided. The high temperature bichromal balls, i.e. those utilizing the purified polyalkylene wax, are then encapsulated. The bichromal balls are dispersed in the silicone oil within a shell of the shell material.
Generally, the present exemplary embodiment can be extended to the purification of any polyalkylene wax, and particularly polyethylene wax. Although nearly any polyethylene wax can be used, typically a wax having a melting point of from about 100° C. to about 150° C. is used, and particularly from about 113° C. to about 126° C. The present exemplary embodiment also utilizes one or more solvent extractions of the wax with one or more isoparaffin solvents, to produce a purified wax. The purified wax, when used in a bichromal ball manufacturing process, enables the formation of bichromal balls that are particularly well adapted for high temperature applications.
A series of trials were performed to further investigate this discovery. In Example 1, extraction of PW2000 (SM151C) was performed as follows. 50 g of powdered PW2000 was suspended in 500 ml ISOPAR® C. The mixture was heated to 80° C. for 4 hours, followed by a hot filtration. The filtered solid was dried under suction for 5 minutes and then re-suspended in 500 ml ISOPAR® C for a second hot extraction at 80° C. This procedure was repeated for a total of three extractions. The filtrates in these three extractions were cooled to room temperature and white solids were formed inside the filtrates. These white solids were collected by suction, dried at 80° C. for overnight. The weight and DSC were recorded on these white residues. In addition, the DSC of regular PW2000 and purified PW2000 were also recorded.
The mass of extracted residue was as follows:
After 1st extraction, residue mass=1.75 g After 2nd extraction, residue mass=0.43 g After 3rd extraction, residue mass=0.15 g Total mass extracted=2.33 g which is about 4.6% of parent weight.
In another example, Example 2, black pigmented wax beads (Sm154A) were prepared as follows. 55.72 g of purified PW2000 was melted at 140° C. 0.28 g of Polyox™ N80 (Dow) additive was then added, followed by 14 g Ferro 6331 black pigment. The mixture was homogenized for 30 minutes at 145-150° C. The melted wax was used to make monochrome beads by a modified benchtop spinner.
A characterization was performed. From the DSC shown in FIG. 1 , there is a small broad peak of around 90 to 110° C. in the parent PW2000. After the first extraction, the residue showed a clear melting characteristic of low molecular weight POLYWAX® which melts around 100 to 110° C. At the same time, after the third extraction, this small broad peak is not clearly seen in the purified PW2000.
Next, leaching was performed as follows. 1.5 g of monochrome beads were mixed with silicone fluid available from Dow Corning under the designation DC200 1cSt fluid (5 ml). The mixture was heated inside a 80° C. oven for 3 hours and then cooled back to room temperature. A first vial containing regular PW2000 black bead and another vial containing purified PW2000 bead were collected. The white precipitate material in the first vial was the leached material which was not found in the other vial.
The present discovery also relates to a purification process for obtaining a refined polyalkylene wax such as polyethylene wax, and specifically, POLYWAX. Specifically, it has been successfully demonstrated to provide a large scale (50 kg) extraction procedure. This procedure is scaleable. This purification step not only provides a solution to the high temperature Gyricon problem, but also enables the alleviation of the batch-to-batch variability of POLYWAX from Baker Petrolite. This batch-to-batch variability results in significant expenditures of time in determining optimum spinning conditions for forming bichromal balls. The root cause is the change in the distribution of molecular weight of POLYWAX. With the implementation of the noted purification step, it is possible to narrow the molecular weight distribution from about Mn=2022, Mw=2434 with PDI=Mw/Mn=1.30 to Mn=2019, Mw=2248 with PDI=1.12, which leads to elimination of the wax variability problem. The extracted material has a molecular weight distribution of Mn=1064, Mw=1233 with PDI=1.16.
The following process describes production of bichromal Gyricon beads with purified POLYWAX 2000.
Step 1: 150-gallon Polywax 2000 Extraction Process
50 kg Polywax 2000 (Baker Petrolite) and 292 kg Ashpar C (Ashland) were charged into a 150-gallon Cogeim filter-dryer that was fitted with a 0.5 um Gortex filter cloth. Mixing was started at 30 RPM, the filter-dryer was heated to 85° C., and the slurry was mixed for three hours at 85° C. The Ashpar C was filtered off by vacuum, leaving a Polywax 2000 wet cake on the filter cloth. 292 kg fresh Aspar C was charged into the filter-dryer, and the Polywax 2000 wet cake was reslurried by mixing at 30 RPM. The filter-dryerwas again heated to 85° C., the slurry was mixed for three hours at 85° C., and the Ashpar C was filtered off by vacuum. The preceding steps were repeated two more times, for a total of four mixing/filtering steps. The remaining Polywax 2000 wet cake was dried at 85° C. for 18 hours in the filter-dryer, and then discharged as a fine white powder. The powder was comilled through a 70-mesh screen to remove lumps. The final product from this procedure will hereafter be referred to as “purified Polywax 2000”.
Step 2: White Pigmented Wax Preparation
6 kg purified Polywax 2000 (from step 1) and 2570 g R-104 titanium dioxide (DuPont) were charged into a 5-gallon plastic pail, and the pail was tumbled for 45 minutes on a jar mill. This blend was then fed at 10 pounds per hour through a ZSK-30 extruder with screw speed set at 300 RPM, six temperature zones set at 90° C. and the circular die set at 120° C. The final extruded composite was a white cylindrical solid and will hereafter be referred to as “white pigmented wax.”
Step 3: Black Pigmented Wax Preparation
6 kg purified Polywax 2000, 1510 g F-6331-2 Black Pigment (Ferro Corp.), and 28.26 g Polyox™ N80 additive (Baker Petrolite) were charged into a 5-gallon plastic pail and tumbled for 45 minutes on a jar mill. This blend was then fed at 10 pounds per hour through a ZSK-30 extruder with screw speed set at 300 RPM, six temperature zones set at 90° C. and the circular die set at 120° C. The final extruded composite was a black cylindrical solid and will hereafter be referred to as “black pigmented wax.”
Step 4: Bichromal Bead Production
1.2 kg white pigmented wax (from step 2) was charged into a Dyanatec Dynamelt, melter-feeder, heated to 155° C., and mixed by hand until melted. 1.2 kg black pigmented wax (from Step 3) was charged into a separate Dyanatec Dynamelt melter-feeder, heated to 155° C., and mixed by hand until melted. When both pigmented waxes were melted, they were fed at 40 g/minute through hoses heated to 135-160° C., through a nozzle heated to 135-160° C., and onto a stainless steel disk (10 cm diameter; 10-mil thickness) rotating at 3900 RPM. The black and white pigmented waxes were metered onto opposite sides of the spinning disk, resulting in production of spherical bichromal beads (i.e., half white, half black). The final bichromal bead product had a wide particle size distribution, and the beads were classified by sieve to retain those in the size range 75 um to 106 um (about 50 wt% of overall product). The final product will hereafter be referred to as “purified Gyricon beads.”
In a trial addressing scale-up of the present discovery process, FIG. 2 illustrates three different samples tested by DSC: virgin PW2000, pilot plant purified PW2000 and bench-scale PW2000. The DSC traces are shown in FIG. 2 .
The virgin PW2000 exhibits a broad endothermic event from 90 to 110° C. which is significantly greater than either one of both purified samples. In addition, the pilot plant sample shows a more silent feature than the bench scale sample. Therefore, the pilot plant sample is more pure than bench scale one.
The following describes fabrication of a device using bichromal balls formed from purified POLYWAX.
Fabrication of Gyricon Sheet (Sample AA569): Sylgard 184 mixture (1.5:10 curing/resin, Dow Corning) was mixed together followed by addition of the same weight of Gyricon beads. After removing the bubbles, the mixture was spread over a carrier substrate sheet, then cured at 90° C. for 2 hrs. Cooling to room temperature occurred, and then a 4 ×6″ sheet was subjected to ultrasonic exposure for 10 minutes. The contrast ratio was measured using (ITO-Mylar/Mylar)/PCB pillow configuration.
The results were as follows. Three Gyricon samples made of three different POLYWAXES were tested side by side: PW1000, Unpurified PW2000, and Purified PW2000. PW1000 beads stopped rotating in 1 hour after placement in an oven at 78° C. Unpurified PW2000 CR stopped rotating after 48 hours and Purified PW2000 sustained its CR. See Tables 9 and 10 below.
TABLE 9
Unpurified PW2000
AA531,
XRCC531
60 V
80 V
100 V
125 V
Time zero
2.13
3.45
4.31
4.49
48 hours
1.16
1.34
1.55
1.86
TABLE 10
Purified PW2000
AA569,
XRCC94
60 V
80 V
100 V
125 V
Time zero
3.67
3.91
3.76
3.57
48 hours
3.55
3.64
3.56
3.40
120 hours
3.26
3.60
3.60
3.50
No optical performance degradation was observed in purified PW2000 Gyricon devices after cycling at 78° C. over 120 hours. Interestingly, the unpurified PW2000 devices rotated much better at 780° than at room temperature. This is consistent with the “precipitation model” for CR loss in this system, i.e. soluble polywax precipitates out in the capsule thereby inhibiting room temperature bead rotation.
Prior to the present discovery, Gyricon devices typically exhibited a 40° C. upper limit operating temperature. Therefore, such devices were generally only used for the indoor signage market. In order to provide outdoor signage, external cooling units were often required which is costly and hampers large scale testing. By utilizing ‘purified’ PW2000, high quality bichromal Gyricon beads are successfully prepared. Devices of ‘purified’ Gyricon bead have shown superior high temperature tolerance. This new package of materials can significantly expand the operating limits of Gyricon devices.
While particular embodiments have been described, alternatives, modifications, variations, improvements, and substantial equivalents that are or may be presently unforeseen may arise to applicants or others skilled in the art. Accordingly, the appended claims as filed and as they may be amended are intended to embrace all such alternatives, modifications variations, improvements, and substantial equivalents.
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Disclosed is a technique for producing bichromal balls that are adapted for use in high temperature applications. The bichromal balls find particular application in signs and display devices that can be used in environments in which the temperature exceeds 40° C.
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This application is a continuation of application Ser. No. 08/685,112 filed on Jul. 23, 1996, now abandoned, which is a continuation of Ser. No. 08/159,880, filed on Nov. 30, 1993.
FIELD OF THE INVENTION
The present invention relates to the field of wireless data transmission and reception. More particularly it relates to inducing rapid fading characteristics and improving reception.
BACKGROUND OF THE INVENTION
In wireless communication systems, such as digital radio or television transmission, an information signal is communicated from a transmitter to a receiver as multiple signals via a channel comprising several independent paths. These multiple signals are called multipath signals and the channel is called a multipath channel. Because of the complex addition of multipath signals, the overall signal strength at a receiver will vary. The phenomenon of received signal strength variation due to complex addition of multipath signals is known as "fading".
A channel encoder (also known as a "channel coder") or similar device can be employed to compensate for fast fading. If the signal strength at a receiver "fades" slowly, however, a receiver experiencing a low signal strength, called a "deep fade", will observe a weak signal strength for a longer period of time than can be readily compensated for using a channel coder. Slow fading is a particular problem in car radio receivers.
Two types of channel coding systems are block coding and convolutional coding. Slow fading may cause a burst of incorrect data symbols at a data receiver. If the burst of incorrect data symbols is short enough the channel coder can detect or correct it. However, when fading is too slow, long bursts of errors can occur which cannot be adequately corrected and unacceptable performance results.
Interleaving/deinterleaving with a channel coder can be used to further combat slow fading. An interleaver at the transmitter rearranges a set of data symbols in a pseudorandom fashion and a deinterleaver at the receiver rearranges the symbols in the original order. However, interleaving/deinterleaving with a channel coder is not sufficient to combat fading if the deep fades last for long enough periods of time.
Spatial diversity can also be used to combat slow fading. Spatial diversity involves the use of a plurality of receiving and/or transmitting antennas. If two receiving antennas, for example, are spatially diverse from one another, the two signals received at the individual antennas will have independent fading characteristics and can be combined to reduce the probability of deep fades, independent of the fading rate.
Unfortunately, spatial diversity may require wide spacing of receiver antennas, typically at least a quarter wavelength. Thus, the receive antennas must be separated by at least 2.5 feet for audio broadcasting at 100 MHz, which is impossible to achieve in small portable receiving systems.
Spatial diversity may also be achieved using multiple transmit antennas. However, transmitting the same signal out of each transmit antenna is not useful, as it just generates more multipath signals at the receiver. One technique previously proposed is to use channel coding with interleaving/deinterleaving in combination with a time varying phase offset between each antenna as proposed in U.S. patent application, Ser. No. 07/890,977, filed on May 29, 1992 to Weerackody which is incorporated herein by reference. This time varying offset creates rapid fading at the receiver antenna, which can be compensated by channel coding with interleaving. For this technique to be effective, however, the signals received from the multiple transmit antennas must be independent. Unfortunately, in digital audio broadcasting (DAB) for example, the transmit antennas are usually very high, e.g., on top of the World Trade Center, to provide wide area coverage. At such heights spacing of tens of wavelengths between the transmit antennas is required to insure substantially independent fading. At 100 MHz with digital audio broadcasting, the required spacing is therefore in excess of hundreds of feet, which is not generally practical.
SUMMARY OF THE INVENTION
The present invention provides a technique for creating rapid fading at the receiver. In digital broadcasting, such as digital audio broadcasting, with rapidly varying fading, channel coding with interleaving is utilized to provide improved performance at the receiver. This addresses the problem presented by slow fading, as with a stationary or slow moving user, experiencing long periods of poor performance such as are typically observed with a slow fade. To create rapid fading, even for a slow-moving user, the signal is transmitted by two orthogonally polarized antennas with a slight time varying offset between the two antennas. Since existing broadcast antennas use orthogonally-polarized antennas, this technique can be easily implemented at the transmitter to overcome the above problem and provide satisfactory performance to all users.
As the reflection coefficient for most objects is polarization dependent, substantially independent fading from two orthogonally polarized antennas can be obtained. A time-varying phase offset, for example, between the antennas creates a time-varying transmit polarization resulting in time varying fading at the receiver. In one embodiment, the transmit polarization is continuously varied from left-hand circular to right-hand circular, two polarizations which have been shown to have high cross-polarization and low cross-correlation on reflection, resulting in substantially independent fading between the signals received at the times of extremes of the transmitted polarization. As most broadcast antennas use linear arrays to direct most of the transmitted energy downward and use two orthogonally-polarized arrays to increase transmitted power by 3 dB (with equal power to each of the polarizations), the technique requires only the addition of a time-varying phase offset, or shift between the orthogonally-polarized signals of standard antennas.
In another embodiment of the invention, more than two transmitting antennas are employed. At least one of said plurality of antennas transmits a signal which is substantially orthogonally polarized with respect to a signal transmitted from at least one other of said plurality of antennas, and a different time varying offset is applied to two or more of the plurality of substantially orthogonally polarized signals to result in fast fading which may be more readily compensated for.
In another embodiment, fast fading is achieved and slow fading is substantially eliminated by receiving a transmitted signal with a plurality of antennas. At least two of these antennas are arranged with respect to each other such that they receive substantially orthogonally polarized signals, and a different time varying offset, such as a time varying phase offset, is provided to one or more of the substantially orthogonally polarized received signals.
The present invention is preferably used in conjunction with interleaving and deinterleaving and channel coding. The present invention can also be used with other techniques such as spatial diversity to further reduce the effects of fading.
Further features of the invention, its nature and various advantages will be apparent from the drawings and the following detailed description of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a situation where a deep fade can occur;
FIG. 2 is a graph of signal strength versus distance which illustrates fading for a single transmitting antenna and a single receiving antenna;
FIG. 3 shows a basic transmitter section illustrative of an embodiment of the present invention;
FIG. 4 is a graph of signal strength versus distance between transmitter and receiver when substantially orthogonally polarized signals and time varying offsets are used in accordance with the present invention;
FIG. 5 shows a further transmitter section according to the present invention;
FIG. 6 shows a receiver section to be used with the FIG. 5 transmitter section of the present invention;
FIG. 7 shows a spatially diverse transmitter section in accordance with the present invention; and
FIG. 8 shows a receiver section which includes two antennas for receiving two substantially orthogonally polarized signals in accordance with a further embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 illustrates a situation where deep fading can occur. In this situation, phasors S 1 and S 2 represent the received signals from two transmitting antennas T 1 and T 2 , respectively. In this situation, destructive addition of the phasors S 1 and S 2 results in a deep fade which can be compensated by the present invention.
FIG. 2 is a graph of signal strength versus distance for a single transmitting and a single receiving antenna. It illustrates fading in a different way than FIG. 1. As shown in FIG. 2, the received signal strength y varies with the distance x of the receiver from the transmitter. At a distance x 1 , the received signal is below a signal strength y 1 , where signal strength y 1 is one below which data reception may be compromised. In the context of a digital audio broadcast being received by a car radio, if the car is moving slowly or is stopped at the distance x 1 from the transmitter, the deep fade may be observed for an unacceptably long time. Such fading may be characterized as slow fading. The present invention reduces the problems arising from slow fading by inducing rapid fading which may be suitably compensated for.
Referring to FIG. 3, a transmitter section 10 according to the present invention is shown. A receiving antenna 35 is also shown. The transmitter section 10 includes a data signal source 20, channels 21 and 22, and an oscillator 26, which applies a time varying phase offset, a mixer 24, and two transmitting antennas 30 and 32.
The data signal source 20 provides a data signal "D", such as a digital audio broadcast signal, to the inputs of both of the channels 21 and 22. The signal D is carried by the channels 21 and 22 to the antennas 30 and 32, respectively. The mixer 24 and oscillator 26 time vary the transmit phase of the signal transmitted from the antenna 30. The rate of variation of the antenna polarization should be about 1-2% of the data symbol rate. A time varying phase offset corresponding to a fixed frequency offset of about 1-2% of the data symbol rate may be used. Therefore, a time varying phase offset which results in a fixed frequency offset of about 3-6 kHz, for audio broadcasting may be used.
The antennas 30 and 32 are linear antennas which are configured to transmit substantially orthogonally polarized signals. Antenna 30 transmits a linearly polarized signal in the vertical plane, while antenna 32 transmits a linearly polarized signal in the horizontal plane. The receiving antenna 35 receives the combined transmitted signals, after transmission through multiple paths, and after modification by noise, delay, and distortion.
FIG. 4 graphically illustrates the rapid fading characteristics created by the present invention. The solid envelope curve 30' shows the signal strength which might be observed at a receiver due to the signal transmitted from a single antenna 30. The dashed envelope curve 32' shows the signal strength which might be observed due to the signal transmitted from a single antenna 32. The curve 31 between the envelopes illustrates the resulting rapid fading signal which might be received by receiver 35 from transmitter 10 with the substantially orthogonally polarized signals transmitted from antennas 30 and 32 with time varying offset applied to the signal transmitted by antenna 30. It should be recognized that FIG. 4 is illustrative only and that the rapid fading signal curve 31 may at times exceed the bounds of the two single antenna signal envelopes 30', 32'. Furthermore, the signal strength will vary even at a fixed distance.
FIG. 5 shows a transmitter 100 according to the present invention. The transmitter 100 includes a digital signal source 120, which includes a message signal source 134, a channel encoder 136, and an interleaver 138. Transmitter 100 further includes a carrier signal source 142, a modulator 144 with first and second inputs, an RF filter and amplifier section 146, channel 121 which includes mixer 124 and oscillator 126, channel 122, and orthogonally polarized transmitting antennas 130 and 132.
Message signal source 134 provides a digital data signal D m to the channel encoder 136. Channel encoder 136 applies an error control coding technique to the signal D m (or a "channel coding" technique) and outputs a signal D e .
The error control coding technique applied by channel encoder 136 may be block coding or convolutional coding. In the case of a typical digital audio broadcast system, the input data rate to the channel encoder is in the range of about 300 kbits/second. Typically, the interleaver is a block interleaver and the modulation scheme is 4-PSK. Additional induced channel variations are introduced by small carrier frequency offsets using mixer 124 and oscillator 126. Suppose f 1 is the carrier frequency transmitted from antenna 130. Then, f 1 =f c +Δf. In this case, f c is the carrier frequency of the signal transmitted by antenna 132 and Δf is the frequency offset at transmitting antenna 130. This fixed frequency offset can be typically in the range of 1-2% of the data symbol rate. Smaller frequency offsets will not sufficiently decorrelate the data symbols at the input to the channel decoder (at the receiver). On the other hand, larger frequency offsets will make the demodulation and the equalization functions difficult. Alternatively, the frequency offset may be applied to the baseband data stream before it is sent to the RF unit and the antenna.
A 200 millisecond delay or duration for interleaving is an appropriate duration for digital audio broadcasting applications. The interleaver 138 is provided to rearrange the data of the signal D e in a pseudorandom fashion. The output of interleaver 138, a signal D i , is provided as an input to the second input of the modulator 144. A second signal, carrier signal C, is provided as an input to the first input of modulator 144. A modulated carrier signal C m is produced at the output of the modulator 144.
The modulation technique used is preferably phase shift keying (PSK), although other modulation techniques such as amplitude shift keying (ASK) and frequency shift keying (FSK) can be used with a digital data source. The modulator can be coherent or employ differential encoding. Coherent modulation, such as PSK, is preferred because an equalizer is preferably used in the receiver. However, differential encoding such as differential phase shift keying can be used.
The signal C m is input to the RF filter and amplifier section 146. In section 146, filters shape the spectrum of modulated carrier signal C m and amplifiers increase the signal strength to an appropriate level for transmission. A filtered and amplified signal C f is produced at the output of the RF filter and amplifier section 146 and applied to the inputs of the two channels, 121 and 122. The signal C f is thus input to both antenna 132 and mixer 124. The oscillator 126 and mixer 124 apply a time varying phase offset, Off a (t) to the signal C f applied to an input of the mixer 124. The offset signal C a is the resultant output signal from the mixer 124. The signals C a and C f are applied for transmission to the antennas 130 and 132, respectively. In this embodiment, the antennas 130 and 132 are preferably helical antennas. With this arrangement, the antenna 130 transmits a right hand circularly polarized signal and antenna 132 transmits a left hand circularly polarized signal.
FIG. 6 illustrates a receiver section 200 which is suitable for use with the transmitter 100 of FIG. 5. The receiver section 200 includes a receiving antenna 235, an RF filter and amplifier section 202, a demodulator 204, an equalizer 206, a deinterleaver 208, and a channel decoder 210.
The antenna 235 receives a combined signal consisting of the addition of the signals C a and C f , after their transmission through various multipaths, and after modification by noise, delay, and distortion. The received signal becomes the input of the RF filter and amplifier section 202. In section 202, RF filters reduce noise and amplifiers increase the received signal strength. The output of the RF filter and amplifier section 202 is then applied to the demodulator 204 which demodulates the signal. The output of demodulator 204 is applied to the equalizer 206 which helps to reduce any amplitude and delay distortion. Equalizer 206 in FIG. 6 can be a decision-feedback type. The output of equalizer 206 is applied to the deinterleaver 208 which is used to rearrange data symbols to undo the process of interleaving which occurred in the interleaver 138 in the transmitter 100. The output of the deinterleaver 208 is applied to a channel decoder 210 which derives the original data message signal, and produces that signal at its output.
Although a frequency offset has been illustrated in FIG. 5, time varying amplitude or other time-varying phase offsets can also be used. The time varying offsets may be continuous or may take on discrete values as a function of time. Time varying offsets can be applied by mechanically moving one of the antennas or preferably by circuits known in the art which electronically apply time varying phase or amplitude offsets to an input signal. For example, an input signal can be applied to first input of a mixer, such as mixer 124, whose second input is a low frequency signal from an oscillator, such as oscillator 126, as shown in FIG. 5. The low frequency signal applies a time varying phase offset (which in this case is the same as a fixed frequency offset) to the input signal.
The time varying offsets introduced to the transmitting antenna signals should not be large enough to cause erroneous data transmission. On the other hand, time diversity of fading improves with faster offsets at the transmit antennas. Preferably, the offsets vary at a rate which is between 1 to 2% of the data rate, for example, a 3-6 kHz rate for 300 ksymbols/sec DAB transmission system. This is small in comparison to the data rate but large enough to cause sufficient time diversity.
While there are a myriad of polarization schemes which would be known to those skilled in the art, it is preferred that antennas in accordance with the present invention be configured to create vertically/horizontally polarized or left/right hand circularly polarized signals. These polarizations create signals which have fading that is highly uncorrelated at the receive antennas.
A carrier signal source in accordance with the present invention preferably produces a sinusoidal signal and may operate at a frequency of about 100 MHz for applications such as FM digital audio broadcasting.
Referring to FIG. 7, a spatially diverse transmitter 300 is shown. The transmitter 300 includes a signal source 302, channels 304, 306, 308, and 310, mixers 312, 314, and 316, transmitting antennas 320, 322, 324, 326, and oscillators 332, 334, and 336.
A signal S is output from the signal source 302 and is applied to the inputs of each of the channels 304, 306, 308, and 310. Each channel but one includes an mixer which has an input connected to an oscillator. Each oscillator applies a different time varying phase offset through its corresponding mixer. Each oscillator frequency is different and each is independent of the signal from the respective channel. Offset signals are produced at the outputs of the mixers 312, 314, and 316, and are applied to the antennas 320, 322, and 324, respectively.
The antennas 320 and 322 are spatially diverse from each other to further reduce the effects of fading. The antennas 324 and 326 are similarly spatially diverse. Antennas 320 and 322 are preferably linear antennas which transmit signals with vertical polarization. Antennas 324 and 326 are preferably linear antennas which transmit signals with horizontal polarization.
The signal source 302 may have components corresponding to the message signal source 134, channel encoder 136, interleaver 138, carrier signal source 142, modulator 144, and RF filters and amplifier section 146, shown in FIG. 5.
Referring to FIG. 8, a receiver 400 according to the present invention is shown. The receiver 400 includes two receiving antennas, 424 and 426, mixer 428, an oscillator 432, a signal combiner 434, and a signal processing block 430.
The antennas 424 and 426 are preferably linear antennas. Antenna 424 transmits with vertical polarization and antenna 426 transmits with horizontal polarization. Mixer 428 and oscillator 432 apply a time varying phase offset to the signal received by the antenna 426. The signal processing block 430 may include elements corresponding to the RF filter and amplifier section 202, demodulator 204, equalizer 206, deinterleaver 208, and channel decoder 210, shown in FIG. 6.
While the benefits of orthogonal polarization with time varying offsets are particularly significant in the context of FM digital audio broadcasting and have been described above principally in that context, to provide transmit diversity of transmitting/receiving antennas in the present invention is also useful for other wireless transmission schemes, such as digital HDTV and the like.
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A system for inducing rapid fading in wireless communication systems, such as digital radio and television transmission is described. Orthogonal polarization combined with time varying offsets are combined to insure rapid fading and result in improved signal reception.
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BACKGROUND OF THE INVENTION
The present invention relates to a fireplace heating unit and more particularly, the invention is directed to a pair or series of isolated and parallel, spatially connected hollow tubing structures having heat exchange air paths with at least three or more zigzag direction reversal paths and in which a single blower supplies air to both tubing structures from a lower air space or outside air which may be mixed with air from the air space surrounding the fireplace with heated air being discharged through two separate outlets in the space being heated.
FIELD OF THE INVENTION
Considerable research and development on fireplace energy saving apparatus indicates need for improved wood burning fireplace heating units.
There has always been a need for supplying additional volume of heated air than for providing for heat itself, since the provision of heated air at temperatures ranging from 200°-250° F. and above is not necessarily useful for heating homes. Many single unit air heating devices with blower arrangements have been inadequate for effective home heating.
The fireplace heating unit for burning wood fuel of the present invention provides for unheated air being supplied partially from an air space substantially beneath the fireplace and hearth area and partially from the space being heated, passing the mixed air through a plurality of zigzag heat exchange areas within the fireplace and hearth area and discharging heated air directly to the air space adjacent the fireplace and hearth with an improved heat-to-air volume ratio.
DESCRIPTION OF PRIOR ART
Devices are known which use a blower arrangement in combination with a hollow grate and in which outside air is supplied to a grate as shown in certain of the following U.S. patents:
U.S. Pat. No. 4,010,729--Mar. 8, 1977--Egli;
U.S. Pat. No. 4,062,345--Dec. 13, 1977--Whiteley;
U.S. Pat. No. 4,161,168--July 17, 1979--Cagle;
U.S. Pat. No. 4,183,347--Jan. 15, 1980--Newswanger;
U.S. Pat. No. 4,256,084--Mar. 17, 1981--Engleman;
U.S. Pat. No. 4,258,879--Mar. 31, 1981--Nischwitz;
U.S. Pat. No. 4,271,814--June 9, 1981--Lister.
None of these patents suggest or disclose hollow grate constructions for directing forced air from a lower air space through a series of zigzag paths connected in parallel arrangement and then directed centrally into an air space to be heated in the manner of the present invention. Thus, none of these patents, whether taken and viewed singly or in combination, are believed to have a bearing on the patentability of any claim of this invention.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a heating unit insertable into a fireplace which uses air from a basement, outside air or other air space in a home with a blower mixing the air and forcing it through a hollow grate having plural and isolated zigzag flow paths and then discharging the heated air into the air space to be heated.
Another object of the present invention is to provide a heating unit that tends to provide low ash accumulation, low fuel consumption, adequate hot air volume to heat the space being heated to an adequate temperature, retaining a comfortable humidity level in the heated air by using more humid air from a lower air space such as a basement or from an outside source.
A further advantage and object of the invention is to provide a heating unit in accordance with the preceding objects in which a blower assembly that forces the air through the grate includes an air gap construction for receiving air surrounding the blower assembly that may be mixed with air drawn from beneath the heated air space. Experience has shown that this source of air through the air gap automatically controls the amount of cold air entering the heated air space in almost direct proportion to air draft up the chimmey.
Still another object and advantage of the present invention is to provide heated air plus humid air to the hollow metal grate for improved heat and humidity characteristics of the resulting heated air.
A still further object of the invention is that instead of the usual cold air movement toward the fireplace, there is provided forced hot air and convectional air movement away from the fireplace to other rooms of the house and heated air space so that maximum and efficient air heating is thereby achieved.
Yet another object of this invention is to provide a forced air heating unit forming a log supporting grate inserted into a fireplace with the grate including two side-by-side isolated heat exchange assemblies each of which includes a plurality of spaced, parallel tubes extending from front to rear of the fireplace with the tubes being connected to define two independent zigzag air flow paths with both of the flow paths receiving air from a single blower and each flow path including a discharge directed outwardly of the fireplace.
Another significant object of the present invention is to provide a zigzag air space in parallel arrangement and having essentially square or rectangular cross sections such that air is directed from a lower and humidified air space directed through a blower and the hollow members comprising a fireplace heating unit so that the resulting heat together with radiant energy from the combustion of fuel in the fireplace is directed into the desired heated air space. Glass doors for the fireplace unit may be provided to increase the performance and appearance of the unit.
These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of an improved fireplace heating unit according to a preferred embodiment and best mode of the present invention illustrating its relationship to a fireplace.
FIG. 2 is a sectional view taken along line 2--2 of FIG. 1.
FIG. 3 is a sectional view taken along line 3--3 of FIG. 2.
FIG. 4 is a sectional view taken along line 4--4 of FIG. 3 showing the details of the improved fireplace heating unit.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings, the fireplace heating unit of the present invention is genereally designated by reference numeral 10 and is illustrated installed in operative position in a conventional fireplace which includes side walls 12, a rear heat reflecting wall 14 and a bottom wall or hearth 16 which is oriented in coplanar relation or elevated above an adjacent floor 18 which is supported in the usual manner by supporting floor joists 22. The construction of the fireplace itself and the surrounding floor, room walls and other house structure is conventional with the heating unit 10 of the present invention capable of being constructed in various sizes depending upon the size characteristics of an existing fireplace. The heating unit 10 is placed on the hearth 16 of the fireplace and becomes a grate for logs 24 which are supported thereon and are burned thereon in a conventional manner. The heating unit 10 may be used with a fireplace having an open front or the front may be closed with transparent doors 26 of conventional construction which are associated with the fireplace opening in the usual manner. In lieu of the door 26, a fire screen (not shown) may be associated with the fireplace opening and the heating unit with either the door 26 or the fireplace screen, if used, being disposed on the upper surface of the heating unit as illustrated in FIG. 4.
The heating unit 10 includes an elongated tubular member 28 extending transversely of the fireplace at the open end thereof with the tubular member 28 resting on and supported by the hearth 16 with the ends of the tubular member extending beyond the side walls 12 of the fireplace. Rigidly connected with and communicated with the tubular member 28 is a plurality of rigid, spaced, parallel tubes 30, 32, 34, 36, 38, 40, 42 and 44 which are perpendicular to the tubular member 28 with the ends of the tubes remote from the tubular member 28 being interconnected by and communicated with a manifold 45 parallel to the tubular member 28 and located in the rear portion of the fireplace adjacent the rear wall 14 as illustrated in FIG. 3. As illustrated clearly in FIG. 1, the spaced parallel tubes provide slot-like openings or recesses 46 in the grate which provide draft supporting air to the undersurface area of the logs 24 resting on the tubes.
The tubular member 28 is rectangular and the manifold 45 is of similar configuration with the tubes 30-44 being rectangular or square in cross-sectional configuration. The upper and lower walls defining the tubular member 28, the manifold 45 and the tubes 30-44 are coplanar. The tube 30 at one end of the heating unit communicates with the tubular member 28 with a baffle 48 extending transversely of the tubular member 28 in alignment with the downstream side wall of the tube 30 thereby causing all of the air passing longitudinally inwardly of the tubular member 28 as it approaches the tube 30 to turn at right angles and pass through the tube 30. At the rear end of the tube 30, the air passes into the manifold 40 and a transverse baffle 50 is provided in the manifold 45 in alignment with the downstream wall of the tube 32 so that all of the air will then pass forwardly in tube 32 and back into the tubular member 28 on the downstream side of the baffle 48 as illustrated by the arrows in FIG. 3. A similar baffle arrangement is provided with respect to the tubes 34 and 36, except that the tube 36 includes two baffles 52 and 54 extending across the tubular member 28 with the front wall of the tubular member 28 including an opening 56 which is a discharge opening for heated air which has passed through the tubes 30-36 with this discharge opening being generally centrally located with respect to the open front of the fireplace and adjacent the floor surface.
Superimposed upon the tubular member 28 is an upper tubular member 58 of less cross-sectional area and of square configuration as illustrated in FIG. 2 with the front wall of the tubular member 28 being substantially flush with the front wall of the tubular member 28 and extending for a length beyond the discharge opening 56 as illustrated in FIGS. 1 and 4. The terminal end of the tubular member 58 includes a closure plate 60 and adjacent the closure plate 60, the bottom wall of the tubular member 58 and the top wall of the tubular member 28 include a pair of adjacent but slightly spaced openings 62 so that air passing longitudinally in the tubular member 58 toward the closed end plate 60 will pass downwardly through the opening 62 in the lower tubular member 28 on the downstream side of the baffle 54 and on the upstream side of a transverse baffle 64 in alignment with the downstream side of tube 38. Thus, the air passes longitudinally of the upper tubular member 28, down through the holes 62 into the lower tubular member 28 and then rearwardly through tube 38, into the manifold 45 where it reverses direction and returns to tubular member 28 through tube 40 because of the transverse baffle 66 in the manifold 45 in alignment with the downstream side of tube 40. The air then returns to tubular member 28 and back to the rear through tubular member 42 and then forwardly through tube 44 where it is directed forwardly by a pair of baffles 68 and 70 extending transversely of the tubular member 28 with the front wall of the tubular member 28 having a discharge opening 72 therein spaced horizontally from the discharge opening 56 for discharging heated air into the room adjacent the floor 18.
With this arrangement, two separate and distinct heat exchange assemblies are incorporated into the heating unit 10 with each of the heat exchange assemblies including a separate air inlet and a separate air outlet. Inasmuch as the lower tubular member 28 which supplies the tubes 30, 32, 34 and 36 is of larger cross-sectional area than the upper tubular member 58, a slightly greater volume of air will be discharged from the centrally located discharge opening 56 than from the discharge opening 72 which is adjacent the side wall 12 of the fireplace. This enables the device to be assembled in a manner so that the discharge opening 72 will be oriented toward that side of the room having the largest space to be heated or adjacent to that side of the room having other rooms adjoining for better distribution of heated air.
The end of the tubular members 28 and 58 remote from the discharge opening 72 is connected with an adapter 74 of rectangular configuration to telescopically fit or abuttingly engage the ends of the tubular members 28 and 58 with a filler 76, illustrated in dotted line in FIG. 2, closing the open space alongside the upper tubular member 58 and above the lower tubular member 28 so that the rectangular adapter 72 will be connected thereto in substantially air-tight relation. The adapter 74 includes a transition member 78 connected with a duct 80 which may be of cylindrical construction and either rigid or flexible and of any desired length. The other end of the duct 80 is connected to a transition member or adapter 82 connected with the outlet 84 of a blower 86 which is of conventional construction and powered by the usual electric motor. The blower 86 may be located in any suitable location and supported in any suitable manner in the room area in which the fireplace heating unit is installed. For example, the blower may be supported on the floor in any suitable manner and preferably by some type of cushioning base to eliminate transfer of vibrations from the blower into the floor and joists. The blower 86 is provided with an intake duct 88 which extends through the floor 18 and is supported from the floor joist 22 in any suitable manner. The upper end of the duct 88 is spaced from the axial intake of the blower 86 to form an air gap or air inlet 90 so that room air can enter the inlet of the blower 86, but the volume of the room air entering the blower will be controlled by the area of the air gap 90. In addition to permitting inlet of room air at a predetermined volume, the separation of the duct 88 from the blower 86 will eliminate transfer of vibrations from the blower 86 into the duct 88 and subsequently into the joists or other supporting structure for the floor 18. If desired, the area of the air gap 90 may be adjusted by providing a telescopically adjusting section on the upper end of the air duct 88. The lower end of the air duct 88 is provided with an inlet 92 which may be oriented adjacent the floor surface of the basement and may also include an outside air inlet provided with a suitable damper control or the like to enable an adjustable volume of air from the basement to be drawn into the blower 86 or an adjustable quantity of outside air or both to be drawn into the blower 86 with any type of air passing through the air duct 88 being mixed with the air drawn into the blower 86 through the air gap 90 thereby enabling any desired mixture of fresh outside air, more humid basement air and recirculated room air to be drawn into the blower 86 and thus forced through the heat exchange unit 10 and discharged into the room for heating the space therein. It is also noted that the glass doors 26 as illustrated normally are provided with a bottom plate 94 usually having draft control means therein so that the bottom edges of the doors 26 if they are swinging doors will pass over the upper tubular member 58 to enable replenishing of the logs 24 in the fireplace. This also provides access to the interior of the fireplace for cleaning ashes from the fireplace and the like.
With this unit, excessive and rapid combustion of wood fuel, normally encountered in fireplaces, is controlled by virtue of the rectangular hollow lower tubular member 28 being placed flat on the hearth in a manner that limits draft air under the logs or firebase on the grate. Further, no live flame is necessary to achieve effective heat transfer from the burning wood fuel to the air passing through the heat exchange tubes thereby substantially reducing wood consumption. The slow burning fire also reduces ash production by a substantial amount and ashes should be removed from between the heat exchange tubes on a daily basis with this being accomplished by using a narrow spatula or other similar device. By constructing the hollow grate of a plurality of heat exchange tubes and by providing a dual inlet and dual outlet isolated from each other, an increased volume of air is circulated through the heat exchange assembly thereby enabling an increased volume of heated air to be discharged into the room without the discharged heating air being at an excessive temperature. The provision of the baffles or stops enables the air to make multiple passes through and under the firebase in each of the heat exchange assemblies, thereby raising the air temperature to a desired level with the increased volume of air maintaining the air temperature below an extremely high level which also reduces the temperature of the heat exchange tubes which results in prolonged life for such tubes before they become burned out due to the high temperatures encountered. By introducing cold air from outside through the vacuum side of the blower to replace air lost by chimney draft, the usual constant infiltration of cold air and movement of such cold air toward the fireplace is eliminated or reduced. Rather, warm air under slight pressure is provided in the room or rooms of a house with which the fireplace is associated. The introduction of fresh air as well as introduction of air from a basement or other remote area provides a source of moisture, thereby maintaining the humidity of the air in the rooms at a more comfortable level. The use of the glass doors 26 prevents entry of smoke or ashes into the room and inasmuch as the air exhausted through the chimmney is replaced, the glass door arrangement is optional, but a fire screen should be used in lieu of the door if it is omitted. In the event the blower fails or the source of electrical power is interrupted, an open top cylindrical pipe may be placed immediately in front of the fireplace and connected to the discharge openings 72 and 56 by suitable pipes or conduits and by opening the doors 26 partially, radiant heat from the fire in the fireplace will cause the vertical pipe to become a hot air stack thereby creating convection movement of air from the heating unit to the room area without the use of the blower.
When installed, the heating unit does not detract from the normal use and view of the fireplace and is capable of continuous use as long as the ashes are periodically removed and the fuel supply periodically renewed. By using glass closure doors for the open front of the fireplace and properly controlling combustion supporting air, the fireplace may be charged with logs at night and the supply of logs in the fireplace need not be replenished until approximately 12 hours later. Thus, considerable time is saved along with the effort and inconvenience of placing logs in the fireplace.
The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.
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A fireplace heating unit apparatus for insertion into a fireplace and hearth arrangement having two parallel heat exchange units forming a fireplace grate with each unit including a series of hollow tubing heat exchange members having a plurality of zigzag air passages therein, an air intake and a blower arrangement for directing heating air through both of the units, and in which the air intake receives air from an air space substantially vertically beneath the fireplace and hearth location. Also provided is an air gap or auxiliary air intake located proximate the blower for admitting air to be heated from the air space proximate the fireplace and hearth and for mixing this air with the air drawn from the lower air space.
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FIELD OF THE INVENTION
[0001] The invention relates to an arrangement for supporting a shell into the barrel of a breech-loading weapon, the arrangement comprising means for fastening a rim-flanged support element to a tail of the shell.
[0002] The invention further relates to a method of fastening a support element to a shell, in which method a support element comprising a rim flange is fastened to a tail of the shell.
BACKGROUND OF THE INVENTION
[0003] A shell mortar may be arranged on a movable base, such as a armoured vehicle, allowing the shell mortar to be conveniently moved from one place to another and, on the other hand, allowing it to be rapidly moved from the emplacement into safety. If the intention is to use the shell mortar for firing horizontally or downwards, the problem is that the shell does not remain in position in the unrifled barrel of the shell mortar, but may slip forward in the barrel in such a manner that it can no longer be fired. U.S. Pat. No. 5,503,080 discloses a support member attachable by means of friction to control fins in the shell tail. However, the friction bond taught by the publication does not achieve a sufficiently reliable fastening of the support member. In addition, the dimensions of a support member and control fins always show some deviations due to the manufacture that cause variation in the magnitude of the fastening force.
BRIEF DESCRIPTION OF THE INVENTION
[0004] An object of the present invention is to provide a new type of arrangement for supporting a shell into the barrel of a breech-loading weapon by using a support element, and a method of fastening such a support element.
[0005] The arrangement of the invention is characterized in that the arrangement for fastening the support element comprises a propelling charge element comprising a propelling charge and a primer, the element having a threading suited for the shell tail in a manner allowing the support element to be fastened to the shell tail by rotating the propelling charge element to the shell tail through the support element. This being so, the propelling charge element is screwed into a threaded cavity inside the shell tail through a centre opening in the support element, whereby the rim-flanged support element is tightened against the shell tail.
[0006] The method of the invention is characterized by supporting the support element against a rear surface of at least one control fin by rotating the propelling charge element placed through the centre opening of the support element into the shell tail.
[0007] An essential idea of the invention is to fasten the support element to the shell tail by means of a new type of propelling charge element. In the propelling charge element, the charge element, e.g. a primer, is in the end part, and the propelling charge, i.e. the so-called basic charge, is placed in the longitudinal shank part thereof. The outer surface of the longitudinal shank part of the propelling charge element is provided with threads. The tail part of the shell is provided with a corresponding cavity for receiving the propelling charge element. The inner surface of the cavity of the tail part is provided with threads matching the threads of the shank part of the charge element. The propelling charge element is fastened to the shell tail through a centre opening in the support element, whereby the support element is tightened against the shell tail. The end part of the propelling charge element and the primer located therein remain visible on the rear surface of the support element. In this case, no separate intermediate triggers are required, since the firing pin of the weapon is able to directly hit the primer of the propelling charge.
[0008] In the invention, the support element is fastened to the shell tail with a mechanical locking, whereby the fastening is more secure than a friction-based locking. A further advantage of the invention is that the support element is easily and rapidly attachable to the shell tail by means of the propelling charge element even under difficult conditions, since the support element may be fastened with the propelling charge element without separate locking pieces.
[0009] The essential idea of an embodiment of the invention is to dimension the length of the propelling charge element in such a manner that when the propelling charge element is fastened to the shell, a distance remains between the shell tail and the support element, the distance serving as a fracturing breaking point under the action of the forces generated by the firing of the shell.
[0010] In the solution according to the embodiment, the breaking portion is provided on that shank portion of the propelling charge element that is not surrounded by the shell tail tube or the support element.
[0011] The breaking point of the propelling charge may also comprise a weakened portion. The weakened portion may be accomplished for instance by machining the wall portion remaining open so that it becomes thinner. In this manner the breaking point may be determined more accurately in advance. However, it should be noted that by varying the wall material or the wall thickness of the propelling charge element, a fastening is achieved that endures the fastening of the support element by rotating the propelling charge element or the shell, but breaks at a predetermined point upon firing of the shell. This provides a simple solution, wherein the structure of the propelling charge is utilized by using it both as a locking piece and in providing the breaking point.
[0012] The essential idea of an embodiment of the invention is that the propelling charge element has a thread suitable for the support element and the shell tail. The thread is on the outer surface in the propelling charge element and on the inner surface in the shell tail.
[0013] The essential idea of an embodiment of the invention is that a recess portion is in connection with the centre opening in the support element, and a rim flange settling in the recess portion of the support element is in the propelling charge element.
[0014] The essential idea of an embodiment of the invention is that the rim flange of the propelling charge element has threads and the recess portion of the support element has threads that match the threads of the rim flange of the propelling charge element.
BRIEF DESCRIPTION OF THE FIGURES
[0015] The invention will be described in more detail in the attached drawings, wherein
[0016] FIG. 1 a schematically shows a shell supported into the barrel of a weapon by means of an arrangement according to the invention,
[0017] FIG. 1 b shows a back view of the arrangement of FIG. 1 a,
[0018] FIG. 2 schematically shows an embodiment of the arrangement of the invention in partial section,
[0019] FIG. 3 a schematically shows an embodiment of the structure of a propelling charge element,
[0020] FIG. 3 b schematically shows an embodiment of the structure of a propelling charge element,
[0021] FIG. 4 a schematically shows an embodiment of the arrangement of the invention in partial section,
[0022] FIG. 4 b shows a back view of the embodiment of the arrangement of FIG. 4 a.
[0023] In the figures, some embodiments of the invention are shown in a simplified manner for the sake of clarity. In the figures, like parts are denoted with like reference numerals.
DETAILED DESCRIPTION OF THE INVENTION
[0024] In FIG. 1 a , a shell 1 is arranged in a barrel 2 of a breech-loading weapon. The weapon may be a shell mortar, wherein the inner surface of the barrel 2 is substantially smooth. The end part of the shell 1 comprises a tail tube 3 and control fins. The tail 4 comprises one or typically, a plurality of control fins for affecting the trajectory of the shell 1 . The details of the structure of the shell 1 may deviate from the structure shown in the figure. For the sake of clarity, the lock of the weapon and the other details thereof are not shown. A support element 6 according to the invention is fastened to the tail 4 for keeping the shell 1 in position in the barrel 2 until it is fired. A rim flange 7 in the support element 6 prevents the shell 1 from shifting forward in the barrel 2 when the barrel 2 is oriented horizontally or even if the barrel 2 pointed downward. Furthermore, the back surface of the weapon barrel may be provided with a groove or a recess into which the rim flange 7 belonging to the support element 6 may settle when the shell 1 provided with the support element 6 is loaded into the barrel. The support element is dimensioned to endure, not only the loads caused by the mass of the shell 1 , but also any forces caused by vibration and accelerations.
[0025] FIG. 1 b shows a back view of the support element arranged in the barrel of the weapon according to FIG. 1 a . An end part 11 of the propelling charge element and a primer 13 thereof are visible in an opening located in the middle of the support element 6 .
[0026] In the following, the structure of an arrangement of the invention will be described with reference to FIGS. 2 to 4 b.
[0027] FIG. 2 schematically shows an embodiment of the invention, wherein the support element 6 is fastened to the tail of the shell 1 by means of a propelling charge element 12 .
[0028] The propelling charge element 12 has a primer 13 in the end part 11 and a propelling charge 14 , i.e. a so-called basic charge, located in a longitudinal shank part 15 thereof. The end part 11 of the propelling charge element and the primer 13 located therein remain visible on the rear surface 62 of the support element, and no separate intermediate triggers are required, since the firing pin of the weapon may directly hit the primer 13 of the propelling charge element 12 . The end part 11 of the propelling charge element 12 has a rim flange 17 that settles into a recess in the middle opening of the support element 6 . In this case, the rim flange 17 of the propelling charge element 6 also restricts the rotating of the propelling charge element 12 too deep into the support element 6 .
[0029] The support element 6 comprises an end 62 , an outer jacket 63 and a rim flange 7 . The outer jacket 63 of the support element 6 is dimensioned in a manner allowing at least part of the tail 4 of the shell 1 to settle to the inside thereof.
[0030] Furthermore, the mid axis of the support element 6 is provided with a sleeve-like reinforcement portion 65 , whose inner circumference is provided with threads for receiving the propelling charge element 12 . The propelling charge element 12 is fastened to the tail tube 3 of the shell through the reinforcement portion 65 . As the propelling charge element 12 is threaded into the inside of the tail tube, the support element also shifts fixed to the shell tail. When being fastened, a surface 32 of the shell tail 4 settles against a surface 64 of the support element. In this position, a distance remaining between the rear surface 31 of the shell tail tube 3 and an upper surface 61 of the reinforcement portion 65 of the support element (shown with reference numeral 120 in FIG. 3 ) serves as the breaking point.
[0031] The distance between the rear surface 31 of the shell tail tube 3 and the upper surface 61 of the reinforcement portion 65 of the support element may preferably be 0.1 to 10 mm, more preferably 0.5 to 5 mm, and most preferably 1 to 3 mm.
[0032] FIG. 3 a schematically shows the principle of the structure of the propelling charge element 12 , wherein threads 15 a are provided on the outer surface of the longitudinal shank part 15 of the propelling charge element, the threads corresponding to the threads in the cavity of the shell tail part. The primer 13 is in the end part 11 of the propelling charge element. In this embodiment, the end part of the propelling charge element 12 has no threads. This being so, the rim-flanged propelling charge element is fastened to the support element with an interference fit, e.g. by compression. Preferably, the propelling charge element is arranged in the support element in a manner allowing the end part to be detached from the support element after the firing of the shell, and a new propelling charge element to be arranged in said support element.
[0033] FIG. 3 b schematically shows the principle of the structure of the propelling charge element, wherein the outer surface of the longitudinal shank part 15 of the propelling charge element is provided with threads 15 a , which correspond to the threads in the cavity of the shell tail part and in the support element. Herein, the threads also extend to the entire end part 11 , but it is clear that an element comprising a rim-flanged primer according to FIG. 2 may also be fastened to the end part.
[0034] The length of the propelling charge element is dimensioned in such a manner that when the propelling charge element is fastened to the shell, a distance 120 remains between the support element of the tail tube of the shell, the distance serving as a breaking point fracturing under the action of the forces generated by the firing of the shell. The breaking point is provided on that shank portion of the propelling charge element that is not surrounded by the shell tail tube or the support element. The structure of the propelling charge element 12 is dimensioned to endure the fastening forces required, but, on the other hand, to break under the action of a predetermined force, thus allowing the shell 1 to be detached from the support element 6 once the firing has occurred. The shank portion 15 of the propelling charge element 12 may be manufactured from a metal sheet by cutting and bending. Alternatively, it may be manufactured from a plastic material for instance by injection moulding or it may be a composite structure.
[0035] FIGS. 4 a and 4 b schematically show an embodiment of an arrangement of the invention. Herein, the propelling charge element 12 is provided with a threaded portion 65 a corresponding to the threads 15 a of the propelling charge element, and a rim flange 17 having threads 65 b . In this way, the fastening of the end part 11 of the propelling charge element to the support element 6 is reinforced. The end part of the propelling charge element 12 is also provided with two recesses 40 , in which a suitable tool may be placed for rotating the propelling charge element into the shell tail or for keeping the propelling charge element 12 in position if the fastening is implemented by rotating the shell. It is to be noted that the recesses shown in FIG. 4 b can also be provided in the arrangement shown in FIG. 2 .
[0036] FIGS. 2 and 4 a show that the end part 11 of the propelling charge element 12 extends from the end surface 62 of the support element 6 at least up to the upper surface 61 of the reinforcement portion 65 of the support element. This being so, the firing of the shell causes no deformation in the reinforcement portion 65 of the support element 6 , allowing the support element 6 to be reused after the end portion 11 of the propelling charge element is detached.
[0037] The support element 6 is installed as follows. Firstly, the support element 6 , the propelling charge element 12 and the shell 1 are arranged in such a manner that their mid axes are aligned. This being so, the propelling charge element 12 may be pushed through the centre opening of the support element 6 and the shank part 15 of the propelling charge element 12 can be rotated into the threads in the shell tail. The propelling charge element 12 is then rotated around its longitudinal axis, whereby the threads 15 a of the shank part 15 of the propelling charge element are threaded into the threads in the centre hole of the shell tail. Alternatively, the propelling charge element is kept in place and the shell is rotated around its longitudinal axis. However, it is essential that the positions of the propelling charge element and the shell are changed relative to one another by rotating one or both of them around their longitudinal axes. In other words, by rotating them relative to one another, their axial positions relative to one another change. When the rotation is continued, the surface 64 of the support element 6 is compressed against the rear surface 32 of the control fin of the tail 4 , and the support element 6 is fastened to the shell 1 , and the arrangement is ready to be pushed into the barrel of a weapon.
[0038] When the shell 1 is fired, the charge breaks the wall of the shank portion that remained open and substantially no material belonging to the support element 6 leaves along therewith that could damage the barrel of the weapon or affect the trajectory of the shell.
[0039] It is obvious to a person skilled in the art that as technology advances, the basic idea of the invention can be implemented in a variety of ways. Consequently, the invention and its embodiments are not restricted to the above examples, but may vary within the scope of the claims.
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The invention relates to an arrangement for supporting a shell ( 1 ) into a barrel ( 2 ) of a breech-loading weapon, the arrangement comprising a rim-flanged support element ( 6 ) attachable to a shell tail ( 4 ). The arrangement is characterized in that the arrangement comprises a propelling charge element ( 12 ) comprising a propelling charge ( 14 ) and a primer ( 13 ), the element having a threading ( 15 a ) suited for the shell tail allowing the support element ( 6 ) to be fastened to the shell tail by threading the propelling charge element ( 6 ) into the tail of the shell ( 1 ) through the support element ( 6 ). The invention further relates to a method of supporting a shell into a barrel of a breech-loading weapon.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to doors and hardware related thereto and, more specifically, to an Adjustable Reinforcing Hinge
2. Description of Related Art
Steel-framed doors are widely used in commercial construction. In particular, the hotel industry uses expensive, high-strength steel frames coupled with heavy duty doors in order to provide superior security as well as long-term durability. FIG. 1 is a perspective view of a conventional hinged door assembly 10 used in hotels and other commercial buildings. The major components of the assembly 10 are a heavy-duty door 12 , a heavy-duty steel door frame 14 , and a door hinge 16 interconnecting the two via a hinge pin 18 .
The problem with the conventional assembly 10 is that when the assembly 10 is subjected to extreme conditions, such as repetitive door 12 slamming or if the door 12 is struck by maintenance (or other) equipment, it is not uncommon for misalignments to occur in the hinge 16 . In particular, the hinge 16 can become partially detached from either the door 12 or frame 14 , or both. Once the hinge 16 begins to separate from either of these elements, the door 12 will no longer open and close properly. In fact, it is very common for the door 12 to no longer provide a fume-tight seal when closed; this can create a problem in satisfying fire code requirements. If we turn to FIG. 2, we can examine one version of a device that seeks to repair or protect the hinges of a door such as depicted in FIG. 1 .
FIG. 2 is a perspective view of a prior art “shock pivot hinge” 20 as described in Gwozdz, U.S. Pat. No. 4,228,561. The Gwozdz pivot hinge 20 consists of a door leaf 22 attached to the door 12 via a plurality of mounting screws 26 , and a upper jam leaf 24 attached to the door frame 14 via a plurality of mounting screws 26 . The leafs 22 and 24 are interconnected by a pivot pin 28 ; the pivot hinge 20 is installed such that the axis of the pivot pin 28 is the same axis as the hinge pin 18 (when the door 12 is closed). After installed, the pivot hinge 20 is intended to prevent the door 12 from sagging when opened due to damaged components in the hinge 16 .
While the Gwozdz device meets its goal when the hinge 18 dimensions are of the type for which the pivot hinge 20 is designed. If, however, a hinge 16 is encountered that is not typical (or at least one for which the pivot hinge 20 is designed to work with), then the leafs 22 and 24 and pivot pin 28 might not be functional. For example, if the gap between the top or side of the door 12 and frame 14 is particularly large, the upper jam leaf 24 might not be able to be securely mounted to the frame 14 , because the frame cannot be reached (due to the fixed length of the pivot pin 28 ). Furthermore, if there are persistent misalignments between the door 12 and frame 14 , the Gwozdz device cannot be adjusted to compensate for them; the relationship between the pivot pin 28 and the leafs 22 and 24 is fixed, and there can be no adjustment. If we now turn to FIG. 3, we can examine yet another attempt at solving the problem of broken hinges.
FIG. 3 is a perspective view of another prior art reinforcing hinge, namely the “non-handed shock arrestor door pivot” 30 disclosed by Colamussi, U.S. Pat. No. 5,056,193. The Colamussi device 30 consists of a frame member 32 attached to the frame 14 by mounting screws 26 , and a door member 34 attached to the door 12 by mounting screws 26 . The members 32 and 34 each have first and second pivot apertures 36 A and 36 B, respectively, formed therethrough for accepting a pivot member 38 therein (i.e. a hinge pin). While the Colamussi device 30 does provide the user with the flexibility of installing the device 30 on either a right-handed or left-handed door 12 (i.e. doors with its hinges mounted on either the right or left side of the door), it does not solve the problems discussed above in connection with the Gwozdz device. Specifically, the pivot member 38 is inserted into the apertures 36 A or 36 B, and then screwed into place; this prevents the vertical distance between the frame member 32 and the door member 34 from being adjusted. Furthermore, as with the Gwozdz device, there is no way to adjust the orientation between the members 32 and 34 and the axis of the pivot member 38 .
SUMMARY OF THE INVENTION
In light of the aforementioned problems associated with the prior devices and systems, it is an object of the present invention to provide an Adjustable Reinforcing Hinge. The hinge of the present invention should act to replace an broken or otherwise damaged door hinge. The reinforcing hinge should be easily adjustable once installed in order to achieve superior alignment between the door and door jam. The hinge should be dimensioned so as to simplify the initial locating and mounting of the hinge on the door and door frame. The process for installing the reinforcing hinge should include the use of the specially-dimensioned elements of the hinge to also act as alignment guides during the location and installation of the reinforcing hinge.
BRIEF DESCRIPTION OF THE DRAWINGS
The objects and features of the present invention, which are believed to be novel, are set forth with particularity in the appended claims. The present invention, both as to its organization and manner of operation, together with further objects and advantages, may best be understood by reference to the following description, taken in connection with the accompanying drawings, of which:
FIG. 1 is a perspective view of a conventional hinge door assembly;
FIG. 2 is a perspective view of a prior art “shock pivot hinge;”
FIG. 3 is a perspective view of another prior art reinforcing hinge;
FIG. 4 is a perspective view of an embodiment of the adjustable reinforcing hinge of the present invention;
FIG. 5 is a plurality of views of the top hinge block of the embodiment of FIG. 4;
FIG. 6 is a plurality of views of the bottom hinge block of the embodiment of FIG. 4;
FIGS. 7A and 7B are an exploded front view of the top hinge block/top plate combination and side view of the top plate embodiments, respectively of the invention of FIGS. 4-6; and
FIGS. 8A through 8H are perspective views depicting the locating jig functionality of the embodiment of the invention of FIGS. 4-7.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The following description is provided to enable any person skilled in the art to make and use the invention and sets forth the best modes contemplated by the inventor of carrying out his invention. Various modifications, however, will remain readily apparent to those skilled in the art, since the generic principles of the present invention have been defined herein specifically to provide an Adjustable Reinforcing Hinge.
The present invention can best be understood by initial consideration of FIG. 4 . FIG. 4 is a perspective view of an embodiment of the adjustable reinforcing hinge 40 of the present invention. As shown, the hinge 40 comprises a bottom plate 42 attached to the door 12 via two or more mounting screws 26 . The bottom plate 42 is further defined by a fin 43 protruding outwardly from the bottom plate 42 substantially at a right angle. Although not depicted, the fin 43 is further defined by two or more slotted apertures, each for accepting a bottom adjustment bolt 46 therethrough. The bottom adjustment bolts 46 , after passing through the slotted apertures (not shown), threadedly engage a pair of corresponding threaded bores formed in a bottom hinge block 44 . More detail regarding these features is provided below in connection with FIG. 6 . As should be appreciated, the slotted apertures (not shown) are slotted (i.e. rather than circular) in order to provide sliding adjustability between the bottom plate 42 and the bottom hinge block 44 . The bottom hinge block 44 is not directly attached to the door 12 or frame 14 ; its only attachment is to the bottom plate 42 (and to the pivot pin 54 , of course).
The hinge 40 further comprises a top plate 48 attached to the door frame 14 by two or more mounting screws. Extending generally at a right angle from the top plate 48 is a fin 49 , which also has at least a pair of slotted apertures formed therein (not shown). Similar to the bottom plate 42 /bottom hinge block 44 assembly, the top hinge block 50 attaches to the top plate by two or more top adjustment bolts 52 passing through the slotted apertures (not shown) and engaging a corresponding pair of threaded bores (not shown) formed in the top hinge block 50 .
Another unique aspect of the hinge 40 of the present invention relates to the pivot pin 54 . The pivot pin 54 is inserted into a pin bore 56 formed in the top hinge block 50 , and further into a corresponding pin bore 60 (see FIG. 6) formed in the bottom hinge block 44 . There is a critical difference between the top pin bore 56 and the bottom pin bore 60 (see FIG. 6 ), namely, that the top pin bore 56 is of a consistent diameter for its entire length, whereas the bottom pin bore 60 is closed on its bottom side (see FIG. 6 ). This design permits the pivot pin 54 to slideably engage both the top and bottom pin bores 56 and 60 , and then rest on the closed bottom end of the bottom pin bore 60 . This unique design permits the horizontal distance between the top hinge block 50 and the bottom hinge block 44 to be easily adapted (i.e. adjusted) for the particular door/frame arrangement; in fact, the pivot pin 54 might even be exchanged with a pin chosen from a group of pins of differing lengths. In order to permit lubrication and/or the expulsion of liquid contaminants, the bottom pin bore 60 (see FIG. 6) may further be provided with a drain aperture 57 ; this aperture 57 would have a diameter smaller than that of the bottom and top pin bores 56 and 60 .
When installing the hinge 40 , the user need simply attach the top and bottom plates 48 and 42 to the frame 14 and door 12 , respectively, after which the top and bottom hinge blocks 50 and 44 are adjusted (via the top and bottom adjustment bolts 52 and 46 ) until the axis of the pivot pin 54 is aligned properly with the hinge pin of the door hinge 16 . Further detail regarding the uniquely simple installation process is provided below in connection with FIGS. 8A and 8B, below. Now turning to FIG. 5, we can review the specific details regarding the top hinge block 50 .
FIG. 5 is a plurality of views of the top hinge block 50 of the embodiment of FIG. 4 . Depicted, we see a front view (V F ), a right side view (V RS ), a top view (V T ), a left side view (V LS ), and a bottom view (V B ). On the right face (F R ), we can see a pair of threaded bores 58 for accepting the top adjustment bolts (see FIG. 4 ). In other configurations, a different number of bores 58 may be provided, for example, to cooperate with more or fewer adjustment bolts (see FIG. 4 ). As is further shown, the diameter of the top pin bore 56 is the same on the top face (F T ), as it is on the bottom face (F B ); this ensures that the pivot pin (see FIG. 4) can slide through the top hinge block 50 smoothly. The top hinge block 50 is generally constructed from a solid piece of strong material, such as steel, however, other materials and construction designs might be feasible. Now turning to FIG. 6, we can review the specific details regarding the bottom hinge block 44 .
FIG. 6 is a plurality of views of the bottom hinge block 44 of the embodiment of FIG. 4 . Similar to the top hinge block (see FIG. 5 ), the bottom hinge block 44 has about two threaded bores 58 on its right face (F R ), for accepting the bottom adjustment bolts (see FIG. 4) therein. In contrast to the top hinge block (see FIG. 5 ), however, the pin bore 60 does not have a consistent diameter through the entire block 44 ; as shown, the bore 60 on the top face (F T ) is a diameter adequate to accept the pivot pin (see FIG. 4 ), however, the bottom face (F B ) has a drain aperture 57 that is somewhat smaller than the diameter of the pivot pin (see FIG. 4 ). such that the pivot pin (see FIG. 4) will rest in the reservoir created by the substantially closed-ended bore 60 . Now turning to FIGS. 7A and 7B, we can examine the hinge invention of the present invention in more detail.
FIG. 7A is an exploded front view of the top hinge block 50 /top plate 48 combination embodiment of the invention of FIGS. 4-6. As shown, the top adjustment bolts 52 pass through slotted apertures formed in the fin of the top plate 48 and into the top hinge block 50 . What is also shown here is an optional shim member 62 sandwiched between the top plate 48 and the top hinge block 50 ; one or more of these shim members 62 might be added to the assembly in order to provide additional vertical dimensional adjustment to the assembly. Also depicted is the slidable pivot pin 54 , as it might be inserted into the top bore (not shown) in the top hinge block 50 .
FIG. 7B depicts a right side view of the top plate of the embodiment of the present invention of FIGS. 4-6. As shown, the slotted apertures 64 are arranged for cooperation with the threaded bores (see FIG. 5 ). Further shown is that in some designs, an adhesive strip 66 is applied to the frame-side of the top plate 48 . The adhesive strip 66 can be a conventional double-sided adhesive tape; it is provided to assist the installer in attaching the top plate 48 to the door frame (not shown). In use, it is a simple matter of removing the protective backing from the adhesive strip 66 , and then sticking the top plate 48 to the door frame; after being stuck in place, it is a simple matter to drill and screw in the necessary mounting screws (see FIG. 4 ).
It should be understood that the top hinge block 50 /top plate 48 combination is essentially identical in its component arrangement as the bottom hinge block/bottom plate combination (see FIG. 4 ). With regard to left- versus right-handed doors, it should be understood further that the threaded bores previously discussed in connection with FIGS. 5-7 would be located on opposite side face of the respective hinge block. Now turning to FIGS. 8A and 8B, we can examine yet another unique aspect of the present invention.
FIGS. 8A through 8H are perspective views depicting the locating jig functionality of the embodiment of the invention of FIGS. 4-7. Step 1 , depicted by FIG. 8A, involves marking a frame edge layout line 70 on the top of the door frame 14 , in alignment with the hinge side of the door 12 . Next, as depicted in FIG. 8B, the bottom hinge block 44 is aligned to the frame layout line 70 (with the left or right face against the door frame 14 ), and a top plate layout line 72 (see FIG. 8C) is marked on the side of the block 44 that is opposite the frame edge layout line 70 . Turning to FIG. 8D, next, the top plate 48 is temporarily attached to the door frame 14 in alignment with the top plate layout line 72 by operation of the adhesive strip located on the back side of the top plate (see FIG. 7 B).
As in FIG. 8E, next the top hinge block 50 is attached to the top plate 72 by the top adjusting bolts 52 . The pivot pin 54 is then inserted into the top pin bore 56 . As shown in FIG. 8F, next the bottom hinge block 44 is slipped onto the pivot pin 54 (see FIG. 8E) and aligned to the edge of the door and frame. Next, as shown in FIG. 8G, the bottom plate 42 is loosely attached to the bottom hinge block 44 by bottom adjusting bolts 46 (and shim members, if necessary). The bottom plate 42 is then temporarily attached (using the adhesive strip on its back side) to the door and the adjusting bolts 46 are tightened. Finally, as depicted in FIG. 8H, the bottom plate 42 is permanently attached to the door 12 by mounting screws 26 .
Those skilled in the art will appreciate that various adaptations and modifications of the just-described preferred embodiment can be configured without departing from the scope and spirit of the invention. Therefore, it is to be understood that, within the scope of the appended claims, the invention may be practiced other than as specifically described herein.
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An Adjustable Reinforcing Hinge is disclosed. Also disclosed isa hinge that replaces a broken or otherwise damaged door hinge. The reinforcing hinge is easily adjusted once installed in order to achieve superior alignment between the door and door jam. The hinge is further dimensioned so as to simplify the initial locating and mounting of the hinge on the door and door frame. The process for installing the reinforcing hinge includes the use of the specially-dimensioned elements of the hinge to also act as alignment guides during the location and installation of the reinforcing hinge.
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BACKGROUND OF THE INVENTION
The invention relates to plating feeders for use in circular knitting machines and in particular knitting machines having arrangements for exchanging feeders during knitting.
Plating may be effected by feeding a pair of individual yarns with one yarn having a lead over the other at a plating angle. The plating angle is critical and requires the yarns to be fed along converging paths from the feeder. Separate mouths are provided on plating feeders for each of the yarns which are spaced from one another.
Feeders on knitting machines may be exchanged during knitting. This involves moving the feeder, trapping and cutting the yarn to separate the last part of the knitted yarn from the feeder, when taking a feeder out of action. When inserting a feeder, the exchange involves laying the yarn between the active needles or licking the new yarn into the hooks of the needles by means of latches.
When applying plating feeders to machines having facilities for exchanging feeders, the requirement for separate and spaced feeder mouths conflicts with the need for precise location of the last part of the knitting yarn for trapping and cutting and of the new yarn for initially feeding it to the needles. In double cylinder machines the problem is more acute as feeder movement up or down is restricted by the cylinders and the only free movement used in exchanging feeders is in a direction tangential to the cylinders.
Another problem arises when plating during reciprocation of a circular machine. In that case the plating angle must be reversed when reversing the direction of knitting so as to maintain the yarns in proper relationship. Whatever the application of a plating feeder, it should also be capable of adjusting the plating angle to adapt it to different requirements. The adjustment is often critical and requires great skill.
It is an object of the invention to provide a plating feeder or a method of control of such a feeder which enables it to be exchanged for another feeder.
It is a further object to provide a plating feeder suitable for use in reciprocatory plating and which is easily adjustable.
It is also an object to provide such plating feeders which may be used on double cylinder machines.
SUMMARY OF THE INVENTION
In accordance with this invention there is provided a plating feeder for use in a circular knitting machine comprising a first mouth for supplying a first yarn and a second mouth for supplying a second yarn movable relative to the first mouth so as to alternatively separate or bring the first and second mouths together. In this way the plating feeder can be operated to alter the angle between the yarns fed by the plating feeder during knitting whenever the plating feeder is moved into or out of the operative plating position. Preferably the first mouth is provided on an elongate first feeder part and the second mouth is provided on a second feeder part, slidable lengthwise on the first feeder part. Advantageously a spring is provided to urge the first and second mouths together and a cam follower is associated with the movable mouth for engaging with a cam to override the spring. Suitably the first mouth is in a form of a narrow aperture for defining a single yarn feed position for a facing yarn and the second mouth is in a form of a trough at least partly surrounding the first mouth for defining alternative, interconnected yarn feed positions for a backing yarn to either side of the first mouth. Thus if the direction of knitting were reversed, the backing yarn would float to the other feed position whereas the facing yarn would not shift sideways. The required plating angle can be maintained for forward, reverse and during reciprocatory knitting. Conveniently the alternative yarn feed positions are arranged symmetrically with respect to the first mouth. The arrangement also has a small height and is thus capable of clearing latchguards in both cylinders of a superposed double cylinder machine and feeding the yarns from positions close to the cylinder. Suitably the first mouth is adjustably supported by a mounting so as to enable the space between the mouth and the mounting to be varied.
The movable mouth may be pivotably mounted instead of slidable to bring the mouths together and separate and/or facilitate reciprocatory knitting. The mouth for the backing yarn may also be narrow to define a single feeding position but this would require a greater spacing between the mouths during plating. Preferably the movable mouth is adapted to feed the backing yarn. The movable mouth could however be adapted to project forward of the other mouth to supply the facing yarn.
Using such plating feeders the yarns can be fed to the needles along paths at a predetermined angle during plating. For commencement of plating, the yarns can be fed parallel and close together to facilitate the licking in of the yarns. In the same way the yarns can be brought into a trapping and cutting block as in the case of a single yarn when terminating the operation of a plating feeder.
The plating feeders can be mounted on any circular knitting machine after the knitting machine has been adapted to exercise control over the relative movements of the mouths of the plating feeder. Preferably the plating feeder is mounted on a feeder mechanism adapted to move the plating feeder in and out of action tangentially with respect to the knitting machine. The first mouth may be moved and the movement timed in many ways such as by cables, hydraulic action etc. Using a cam control however a simple and reliable construction can be made. Preferably then a stationary cam arrangement is associated with the knitting machine for controlling the movement of the second mouth. The cam may be operative to control the position of the second mouth along all or part of its path as the plating feeder is moved into or out of action and the cam action may be effected using a cam and the cam follower associated with the movable mouth urged against the cam by a spring. Preferably the cam arrangement is adjustable to vary the extent of separation of the first and second mouth and the cam arrangement comprises a single cam for separating the second mouth from the first only at the plating position of the plating feeder. The plating feeder is preferably mounted so as to have the feeder parts mounting the first and second mouths extending radially with respect to the circular knitting machine. The plating feeder may be one of a plurality of alternative feeders of a yarn changing mechanism adapted to exchange feeders during knitting. Conveniently the mechanism is of a type in which the feeders are taken in and out of action by a sliding movement of a shank on which the respective feeders are mounted in a direction tangential to a cylinder or cylinders of the circular knitting machine as described in the British Patent specifications 301,350 and 301,360. Preferably the cam is arranged so as to move the second feeder part away from the needle cylinder against a spring action and to allow the spring to move the first and second yarns, emerging from the feeders close together when the plating feeder is moved to either side of the cam.
In accordance with this invention there is also provided a method of plating for a limited period while knitting is in progress on a circular knitting machine which method comprises feeding a backing and facing yarn to needles of the circular knitting machine from separate and relatively movable feeder mouths, controlling said feeder mouths to move the backing and facing yarn together at the commencement and/or termination of plating and controlling said feeder parts to supply the backing and facing yarn at a predetermined angles respectively to the needles while plating.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is particularly described with reference to the drawings in which:
FIG. 1 is a perspective view showing a plating feeder according to the invention in its operative position mounted in a feeder cage;
FIG. 2 is a plan view of the plating feeder of FIG. 1 in its rest position with the yarns held in the trapper;
FIG. 3 is a plan view of the plating feeder of FIG. 1 in a position suitable for presenting the yarns to the needles; and
FIG. 4 is a plan view of the plating feeder of FIG. 1 in its operative position as shown in FIG. 1.
DESCRIPTION OF PREFERRED EMBODIMENT
With reference to the Figures, there is shown part of a superposed double cylinder knitting machine having needles N with latches L in rotatable cylinders and a yarn changing mechanism mounted outside the cylinders which comprises a yarn cutting and trapping block and a number of alternative yarn feeders. The yarn changing mechanism is substantially as described in the British Patent specifications 301,350 and 301,360. All feeders are adapted to move towards or away from the needle cylinders to take them in or out of action by a feeder shank 15 slidably mounted for movement in a tangential direction in a fixed U-bracket 26. The feeder shank 15 comprises a mounting for securing one of the feeders to the bracket 26 of the knitting machine. The feeders are adapted move up or down as required during such sliding movement by the engagement of a pin 24 mounted on a block 23 fixed to the shank 15 with a slot 27 formed in a plate 25 which causes the shank 15 to rotate. For fine adjustment of such up and down movements, the plate 25 is adjustable by means of a vertical slot 28 and a screw 29 for locking the plate to the U-bracket 26. One of the feeders is adapted for plating and will now be described in detail.
On the end of the feeder mounting shank 15 is mounted a connecting block 12 through which is bored a hole holding a rod-like feeder part 10. The feeder part 10 is held in position with respect to the block 12 by a lock-screw 13. Fine adjustment of the position of the feeder part 10 can be effected by an adjusting nut 14 screwed onto the feeder part 10 and engaging the block 12. The feeder part 10 extends generally towards the needle cylinder and is provided at the end 10a which is directed to the needles with a mouth in the form of a hole 10b for guiding a yarn.
On the rod-like feeder part 10, intermediate the end 10a and the connecting block 12, is mounted a trough-shaped feeder part 11. The trough-shaped feeder part 11 is provided with a longitudinal slot 21 through which a pin 20 fixed to the feeder part 10 protrudes. By this arrangement rotation of the feeder part 11 around the feeder part 10 is prevented. The feeder part 11 can thus slide along the feeder part 10 within the limits of the slot 21. The two ends of the slot provide the maximum and minimum separation of the two feeder parts 10 and 11. The trough shaped feeder part 11 is urged towards the needle cylinder by a compression spring 22. At the end facing the needles both sides of the trough shaped feeder part 11 are bent upwardly and inwardly at the end 11 facing the needles forming a substantially U-shaped mouth. A slot 11b is further formed in the bottom of the troughlike feeder part 11 adjacent the end 11a. The slot 11b has a straight edge towards the front of the part 11 and a curved edge towards the rear, which converges to the straight edge in the region where the sides of the trough-shaped feeder part 11 are bent upward and inward. The position of the feeder part 11 is controlled by a camplate 16 which engages a roller 17 mounted on an upright pin 18 on the part 11. The camplate 16 is mounted on a fixed bracket 19 by two screws 16a and 16b, one of which is mounted in the bracket 19 through a slot 16c in the camplate 16. The camplate 16 is arranged to have a generally horizontal portion 16d whose edge engages the roller 17. As seen in FIG. 1, the horizontal portion 16d is offset downwards with respect to the portion of the camplate 16 secured to the bracket 19 so as to enable movement of the roller 17 beneath the camplate 16 as portrayed in FIG. 2.
The extent of sideways movement of the plating feeder can be adjusted by means of a stop screw 30 mounted in the bracket 26 which is arranged to abut with the rod-like feeder part 10. One plating yarn (Ya) can be threaded through take up guide C and a guide A on the rod-like feeder part 10 to pass through the hole 10b. Another plating yarn can be threaded through a take-up guide D and guide B to pass through the slot 11b into the mouth formed by the space left between the upstanding portions at the end 11a of the feeder part 11. In this way the yarn is held steady in the feeder part 11.
The plating feeder movements can be adjusted as required in the following ways:
1. The rod-like feeder part 10 which feeds the face yarn to the needles is adjustable towards or away from the axis of the cylinders by releasing the lock screw 13 and rotating the adjusting nut 14 anti-clockwise or clockwise respectively;
2. The trough-like feeder part 11 which slidably locates over the feeder part 10 and serves to feed a backing yarn to the needles is controlled by the cam plate 16. The correct separation between the two feeder parts 10 and 11 can be obtained by releasing the camplate 16 and rotating it on the screw 16b in the rquired direction, then re-locking the screw 16a which passes through the slot 16c into the fixed bracket 19;
3. Heightwise adjustment of the yarn feeding ends 10a and 11a of the plating feeder is obtained by adjustment up or down of the feeder control plate 25. The feeder control plate 25 carries the slot 28 which permits the plate to be adjusted up or down when released by the locking screw 29.
In operation with the plating feeder at rest in the non-operating position (FIG. 2) the two yarns Ya and Yb are held in a cutting and trapping block 31 situated adjacent to the plating feeder.
When it is required during the knitting cycle of the machine to bring the plating feeder into a yarn feeding position, movement is initiated by the yarn changing mechanism, causing the feeder shank 15 to slide through the bracket 26 until the pin 24, following the cam profile in the control slot 27, comes to rest at a point near Z, through the rod-like feeder part 10 coming into abutment with the adjustable stop screw 30 (FIG. 3). With the plating feeder in this position, the yarns Ya and Yb still held in the cutting and trapping block 31 are brought closely adjacent to the needles passing down the knitting cam which allows the closing latch L of the needle N to lick the yarns Ya and Yb into the hook of the needle. The two yarns Ya and Yb have a minimum of separation at this stage because the roller 17 has lost contact with the cam plate 16, allowing the spring 22 to push the feeder part 11 forward to the limit of the slot 21. As soon as the yarns Ya and Yb are engaged by the needles N, the trapper block 31 is opened to release the yarn ends, and the feeder is moved to its correct feeding position by the yarn feed mechanism, the pin 24 reaching the point Y on the feeder control plate 25. (FIG. 1). At the same time the roller 17 comes into engagement with the camplate 16 which causes the feeder part 11 to slide along the feeder part 10, compressing the spring 22 and separating the yarns Ya and Yb into a proper plating relationship (FIG. 4).
The correct yarn feeding position of the plating feeder is set in such a way as to ensure that the two yarns Ya and Yb are delivered to the needles in a correct plating relationship for both forward knitting and reverse knitting. The plating feeder can be set to lie on a radial line through the axis of the needle cylinder when at its yarn feed position (FIG. 4) (the two yarns Ya and Yb are shown in full lines for forward knitting and chain dot lines for reverse knitting.) It will be seen that the backing yarn Yb is permitted to float from one side of the slot 11b to the other according to the direction of knitting during reciprocation of the needle cylinder when producing heels and toes, and this makes sure that the feed angle between the two yarns remains the same in both directions of knitting.
When it is required during the knitting cycle of the machine to withdraw the plating feeder from its active position, movement is again initiated by the yarn feed mechanism to cause the feeder shank 15 to slide through the bracket 26 until the pin 24, following the cam profile in the control slot 27, comes to rest at a point `X`. During this movement of withdrawal, the two yarns Ya and Yb and the two feeder parts 10 and 11 remain separated until the roller 17 loses contact with the edge of the horizontal portion 16d of the camplate 16. This allows the feeder part 11 to slide along the rod-like feeder part 10 under pressure of the spring 22 until the pin 20 is engaged by the end of the slot 21 (FIG. 2). Thus the two yarns are caused to feed together, one above the other around the flank of the trough-like feeder part when entering the cutting and trapping block 31.
To avoid contact and damage to the needle latches when the plating feeder is introduced or withdrawn, the feeder cage is controlled in the well known manner by the yarn feed mechanism disclosed in the British Patent specifications Nos. 301,350 and 301,360.
In practising the invention it can easily be arranged that the face thread which is to appear at the outer face of the fabric, and the backing thread which is to appear at the inner face of the fabric, are fed to the knitting needles of the machine so that the threads will be engaged by the hooks of the needles in their proper relationship when each stitch is drawn, the face thread lying in the hook of the needle close to the shank and the backing thread lying in the hook of the needle on the outer side of the face thread. The same setting of the plating feeder can be made to give the proper relationship when rotating the needle cylinder in either direction or during reciprocatory knitting when the cylinder reciprocates during the production of heels and toes.
The yarns can be led in a separated condition to the needles during plating. On withdrawal of the feeder the yarns can be easily cut and trapped in a trapper since the two yarns lie close together during withdrawel of the feeder. By providing separate control of the angle between the yarns during plating and during commencement and termination of feed, the setting of the plating angle is less critical as the operator need not be concerned with reducing this angle as much as possible so as to ensure proper trapping and feeding of the new yarn. The plating feeder can thus also be used satisfactorily for a wide range of yarns.
The plating feeder has feeder parts 10 and 11 for the face and backing threads which are individually adjustable and which can be moved relative to one another automatically during knitting to give a proper angle for plating and bring them close together for the initial feeding to the needles and the final cutting and trapping. Thus the plating feeder in a particular adjustment position can cope with a variety of yarns.
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A plating feeder for use in a circular knitting machine comprises a first mouth for supplying a first yarn, and a second mouth for supplying a second yarn and which is movable relative to the first and second mouths together to alter the angle between the yarns fed by the plating feeder during knitting. The first mouth is provided on an elongate first feeder part and the second mouth is provided on a second feeder part slidable lengthwise on the first feeder part. A biasing spring urges the first and second mouths together and a cam follower coacts with the movable mouth and engages with a cam to override the spring. The first mouth is in a form of a narrow aperture for defining a single yarn feed position for a facing yarn and the second mouth is in a form of a trough at least partly surrounding the first mouth for defining alternative, interconnected yarn feed positions for a backing yarn on either side of the first mouth.
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BACKGROUND OF THE INVENTION
[0001] (a) Field of the Invention
[0002] The invention relates to the immunization of animals and humans with trypanosome tubulin to protect against trypanosomes.
[0003] (b) Description of Prior Art
[0004] African trypanosomes belong to the genus Trypanosoma, are transmitted by tsetse flies of the genus Glossina and cause a variety of severe diseases collectively known as trypanosomiasis in man and animals. The main pathogenic species in animals are T. conglense, T. vivax, T. smiae and T. b. brucei and the disease they cause is collectively known as Nagana. T. b. brucei is morphologically indistinguishable from the human parasites, T b. gambiense and T. b. rhodesienise which, respectively, cause the chronic Gambian and the acute Rhodesian types of sleeping sickness. However, T. b. brucei cannot infect humans and becomes lysed in human blood in vitro, but under certain conditions can switch to a human form and vice versa. Therefore, the current control methods and the search for novel control tools for the human and animal diseases are linked.
[0005] Immunological control has been frustrated by antigenic variation (Barry, J. D. (1997) Parasitology Today, 13:212-217) and as such the control of African trypanosomiasis is restricted to vector control, chemoprophylaxis (in animals) and treatment of sick animals and humans (Barret, J. C. (1997) Control Strategies of African Trypanosomiases: Their sustainability and Effectiveness. In: G. Hides, J. C. Mottram, G. H. Combs and P. H Holmes, (Eds.) Trypanosomiasis and Leishhmaniasis . pp 347-362). Each of these approaches has important limitations (Barret, J. C. (1997) Control Strategies of African Trypanosomiases: Their sustainability and Effectiveness. In: G. Hides, J. C. Mottram, G. H. Combs and P. H Holmes, (Eds.) Trypanosomiasis and Leishmaniasis . pp 347-362) and the search for new drugs continues at a low level. However, typanosomiasis remains a major tropical disease, affecting mainly the poor of the world who don't attract the interest of the pharmaceutical companies.
[0006] Trypanosomes have a unique capacity for antigenic variation at the cell surface which is the basis of their ability to evade the host immune response and because of this, prospects for the development of a vaccine against African trypanosomiasis have been considered poor.
[0007] Despite the poor prospects of finding a vaccine, the most effective and sustainable way of controlling trypanosomiasis would be a safe and cost-effective vaccine (Newman, M. J. et al. (1995) Immunological Formulation design considerations for subunit vaccines. In: M. F. Powell and M. J. Newman (ed) The Subunit and Adjuvant Approach . Plenum Press, New York). Because of this, the search for a suitable anti-trypanosome vaccine continues.
[0008] Partial protection has been reported against African trypanosomosis using irradiated trypanosomes (Morrison, W. I. et al. (1982) Parasite Immunology, 4: 395-407). The infection and treatment method has also been tried but only increased the prepatent period and survival time after challenge but did not prevent infection (Scott, J. M. et al. (1978) Reviews in Veterinary Science, 25: 115-117).
[0009] Surface antigens that can be used as the basis for a vaccine against trypanosomiasis include, two glycoproteins namely, the variable surface glycoprotein (VSG) of the bloodstream forms, which occur in mammalian hosts, and procyclin of the procyclics which occur in the-insect vectors. Procyclin has not attracted a lot of attention for vaccine development. The mammalian host makes a good immune response to the first wave of invading trypanosomes by producing antibodies against the first wave of VSGs called metacyclic variable antigenic types (M-VATs). However before all the parasites can be eliminated, trypanosomes switch to the blood stream VSGs which also induce protective antibodies but again before these are removed by this new wave of antibodies, more trypanosomes (approximately one in every 10 4 -10 5 ) turn off the genes controlling the expression of the initial VSG and switch to genes for expression a different VSG molecule, not recognized by the animal's initial immune response; and so the process continues with the parasite population bearing new VSGs and always keeping a step ahead of the host's immune system (Barry, J. D. (1997) Parasitology Today, 13:212-217). Protective immunity can readily be achieved against a given trypanosome strain but because of antigenic variation animals remain susceptible to heterologous challenge (Scott et al., 1978). Trypanosomes are able to express an infinite variety of VSGs and therefore a vaccine based on these abundant surface antigens is now out of the question.
[0010] Given their functional role, plasma membrane proteins are unlikely to undergo antigenic variation (Barry, J. D. (1997) Parasitology Today, 13:212-217) in the same manner as the VSGs and consequently may represent suitable targets for the development of vaccines. However, since they are concealed by the glycoprotein envelope, studies with the plasma membrane proteins have not yielded encouraging results (Murray, M. et al. (1985) Parasitology, 91:53-66).
[0011] Cytosolic fractions of trypanosomes have also been used and shown to have constant antigenic properties though they have been considered poor immunogens. The use of purified antigens has an advantage in that it doesn't include irrelevant antigens or proteins which may overwhelm or suppress the host immune system. In addition, knowing a specific immuno-protective antigen would enable cloning and synthesis of its recombinant form and its known DNA sequence would thus allow further modifications to optimize immuno-protection attributes. However, pure trypanosome proteins as such have not been identified for vaccination, but flagella pocket fractions of African trypanosomes have been used to immunize laboratory or large animals (Mkunza, F. et al. (1995) Vaccine, 13: 151-154). These studies showed that susceptible hosts may be partially protected whereby the immunized animals lived longer than the controls upon challenge with a lethal dose of trypanosomes. However, studies resulting in complete protection have also been reported using the flagella fraction quiz, A. M. et al. (1990) Molecular and Biochemical Parasitology, 39: 117-126) of T. cruzi and a fraction of T. brucei consisting of a microtubule associated protein (MAP 52) and two glycosomal enzymes (Balaban, N. et al. (1995) Journal of Infectious Diseases, 172: 845-850). On the other hand, immunization with similar flagella pocket fractions of T. rhodesiense in mice and cattle (Mkunza F. et al. (1995) Vaccine, 13: 151-154) gave a partial protection to heterologous challenge. Certain recombinant antigens have also been explored for protection against T. cruzi infection (Taibi, A. et al. (1995) Immunology Letters, 48: 193-200; Costa, F. et al. (1998) Vaccine 16: 768-774; Wizel, B. and Tarleton, R L. (1998) Infection and Immunity, 66; 5073-5081) but their application in African trypanosomiasis has not been reported.
[0012] Our interest has been focused on the cytoskeleton and particularly the microtubules (Lubega, G. W. et al. (1998) South African Journal of Science. 94 284-285). The cell body of trypanosomes is tightly enveloped by a compact single layer of microtubules, which are situated immediately beneath the surface membrane. These pellicular microtubules provide a high degree of flexibility to the cells, mechanical stability and motility and together form the dominant cellular architecture. Microtubules are also found in the flagellum, where they form one of the two prominent structures of this organelle, the axoneme. The other is the paraxial rod which is essentially a network of actin fibers, which extends along the axoneme and stays in close contact with it. In trypanosomes, it has been observed that pellicular and flagella microtubules are immunologically distinct. A third domain of microtubule function in the trypanosome is the formation of the spindle apparatus of dividing nuclei. Microtubules are cross linked to the plasma membrane by MAPs and together build into complex assemblies such as the mitotic spindle, flagella, axonemes and neurotubules.
[0013] The major building block of microtubules is a protein known as tubulin which is usually a heterodimer of α and β subunits and exists in all eukaryotic cells. However, the properties of tubulin of lower eukaryotes such as protozoa and helminths differ from those of higher ones such as mammals which makes it possible to selectively target the parasite tubulin. Consequently, tubulin is the target of benzimidazole anthelmintics.
[0014] Tubulins are a multigene family of related proteins which, in trypanosomes, are comprised of three related proteins each about 55 kDa termed α, β and γ-tubulin (Kimmel, B. et al. (1985) Gene, 35: 237-248). Whereas α-tubulin of trypanosomes exists in two isoforms α1- and α3-tubulin, β-tubulin has only one single isoform which is very interesting because the β-tubulin appears to be the primary target for chemotherapy (Lubega, G. W. and Prichard, R. K (1991) Haemonchus cointortus. Molecular and Biochemical Parasitology, 47: 129-138) and probably for immunotherapy (Lubega, G. W. et al. (1998) South African Journal of Science. 94 284-285).
[0015] In this study, trypanosome tubulin was investigated for its potential as a vaccine target. The rationale for using tubulin was that it participates in very vital cellular functions, it is well distributed in the trypanosomes, there are differences between the mammalian and trypanosome tubulin and its biochemical nature remains unchanged throughout the life cycle of the trypanosomes and it is the single most abundant protein of the cytoskeleton.
[0016] The potential of tubulin as an immunotherapeutic target was demonstrated with Brugia pahangi whereby monoclonal antibodies raised against β-tubulin peptides destroyed the surfaces of the filarail worms in vitro and reduced microfilaraemia and the survival of the adult worms in vivo (Bughio, N. I. et al. (1993) International Journal of Parasitology, 23: 913-924).
[0017] Lubega et al. (Lubega, G. W. et al. (1998) South African Journal of Science. 94 284-285) showed that the tubulin enriched extract from a strain of T brucei conferred protection against the same strain of T. brucei in vivo, or inhibited the development of the same strain of T. brucei in vitro. Thus there was evidence for protection against homologous strain of Trypanosoma brucei . Homologous protection has been acheived before with other trypanosome extracts and it is known that variable surface glycoprotein (VSGP) of trypanosomes can confer very strong homologous protection. However, because in vivo, the trypanosome can change its VSGP, once the host mounts a strong immune response, the parasite can continue to proliferate and attempts to develop a vaccine against sleeping sickness and Nagana have so far been frustrated.
[0018] It would be highly desirable to be provided with means for the immunization of animals and humans with trypanosome tubulin to protect against any trypanosomes or to provide for protection against heterologous strains of different species of Trypanosoma.
SUMMARY OF THE INVENTION
[0019] One aim of the present invention is to provide means for the immunization of animals and humans with trypanosome tubulin to protect against any trypanosomes or to provide for protection against heterologous strains of different species of Trypanosoma.
[0020] Surprisingly and in accordance with the present invention, there is provided a purified tubulin preparation from trypanosome which can produce a strong protection not only against the homologous strain (from which the tubulin antigen was prepared), but also against heterologous strains of different species of Trypanosoma. Furthermore, the data of the present invention demonstrate that the protection is independent of VSGP.
[0021] In accordance with the present invention, there is provided a substantially pure tubulin preparation, which comprises a tubulin extract from Trypanosoma brucei, wherein said tubulin preparation can protect animals and humans against heterologous strains of different species of Trypanosoma.
[0022] In accordance with another embodiment of the present invention, there is provided a method for the immunization of an animal or a human patient against heterologous strains of different species of Trypanosoma, which comprises administering to said animal or human patient an immunogenic amount of a tubulin extract preparation isolated from a Trypanosoma.
[0023] The preferred Trypanosoma is Trypanosoma brucei.
[0024] In accordance with another embodiment of the present invention, there is provided a vaccine against trypanosomiasis in animals or humans, which comprises an immunogenic amount of a tubulin extract preparation isolated from a Trypanosoma or an immunoprotective amount of an antibody raised against a tubulin isolated from a Trypanosoma.
[0025] In accordance with another embodiment of the present invention, there is provided an antibody raised against the tubulin preparation of the present invention.
[0026] The antibody may be a polyclonal or a monclonal antibody.
[0027] In accordance with another embodiment of the present invention, there is provided a vaccine against trypanosomiasis in animals or humans, which comprises an immunogenic amount of a recombinant tubulin which corresponds in composition to a tubulin extract preparation isolated from a Trypanosoma or an immunoprotective amount of an antibody raised against said recombinant tubulin.
[0028] In accordance with another embodiment of the present invention, there is provided a vaccine against trypanosomiasis in animals or humans, which comprises an immunogenic amount of a synthetic peptide which corresponds in composition to portion of an amino acid sequence of a tubulin extracted from a Trypanosoma or an immunoprotective amount of an antibody raised against said tubulin peptide.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] [0029]FIG. 1 illustrates the purity by SDS-PAGE and Western blot of tubulin purified from T. brucei . Tubulin was purified from T. brucei ( T.b ) or rat brain (Rb) as described in Materials and Methods and and a sample run on a 10% SDS-PAGE gel and stained with Coomassie blue (Panel A) or processed for Western blot (Panel B) using anti-chicken tubulin monoclonal antibodies before being used in immunization experiments.
[0030] [0030]FIG. 2 illustrates the effect of the route of immunization or synthetic tubulin peptides (STP) on the rate of antibody development. Mice were immunized with nThTub subcutaneously (sc) or intra-peritoneally (ip), or with STP14 (sc) and booster doses given on day 15 and day 30. The immune or pre-immunization serum were diluted (1:200) and used in ELISA assay. The mean±SD for the pre-immune OD readings was determined and the immune net OD readings calculated by subtracting this mean±2SD from the various immune readings. The results were then plotted as mean net OD readings±SEM (n=10).
[0031] [0031]FIG. 3 illustrates the specificity by Western blot of the various anti-tubulin antibodies. Trypanosome total soluble extracts from T. brucei UTRO 010291B ( T.b ), T. rhodesiense UTRO 080291B (T.r) or T. congolense UTRO 161098B ( T.c ) or rat brain soluble extracts (Rb) were run on a 10% SDS-PAGE and stained with Coomassie blue (Panel A) or transferred to nitrocellulose membrane and probed with various mouse anti-sera as follows: anti-RbTub (Panel B), anti-nThTub (Panel C), anti-dThTub (Panel D) or anti-STT14 (Panel E) or pre-immunization sera (Panel F).
[0032] [0032]FIG. 4 illustrates the comparison of peak levels and specificity of antibody responses following immunization with the various antigens. Mice were immunized with nThTub, dThTub, ST? 14 or RbTub as described in Materials and Methods. The immune or pre-immunization sera from the mice were diluted (1:200) and cross-tested by poly-L-lysine ELISA against these various antigens.
[0033] Net OD readings±SEM (n-10) were calculated as in FIG. 2 above.
[0034] [0034]FIG. 5 illustrates the effect of dilution and incubation time on trypanosome growth. Trypanosomes were cultured in the presence of different dilutions (x36, x108, x324, x 972, or x 2916) of anti-nThTub immune serun or pre-immunization serum diluted 12 times. Incubation was continued for 8 days with change of medium every 48 hrs. Trypanosome counts were made every 24 hrs using the Improved Neubeur Haemocytometer and counts expressed as cells per 100 ml of incubation medium.
[0035] [0035]FIG. 6 illustrates the comparison of trypanosome growth inhibition (%) by the various immune sera. T. brucei grown and adapted for continuous growth in complete bloodstream-form medium (CBM) were incubated in the presence of different dilutions of immune sera to native (nTbTub) or denatured (dThTub) T. brucei tubulin, or synthetic tubulin peptides (STP12), and trypanosome counts were made every 24 hrs of incubation. Medium was changed after 48 hrs as described in Materials and Methods. The differences in cell counts, after 24 hrs or 96 hrs, between the control and each test serum were expressed as the percentage of counts in the control. The values are mean±SEM of 4 duplicate experiments.
[0036] [0036]FIG. 7 illustrates the agglutination of trypanosomes cultured in the presence of immune serum. Trypanosomes in log phase of growth were incubated with pre-immunization serum (A) or anti-nTbTub immune serum (B). Agglutination is evident in (B) at various stages of agglutination (arrows). Free trypanosomes in (B) are deformed but those in (A) are not.
[0037] [0037]FIG. 8 illustrates the immunofluorescence staining of Trypanosoma brucei . Intact (A) or permeablised (B-F) cells of T. brucei were incubated with immune sera to nThTub (B), dThTub (C), STP12 (D), RbTub (E) or pre-immunization serum (F) and developed with fluorescein-conjugated Protein A as described in Materials and Methods. The uniformly fluorescing permeablised trypanosomes (arrows) in B, C, and D can be seen. The intact (i.e non-permeablised) trypanosomes fluoresced (only spots can be seen) at the posterior (possibly flagella pocket) region (A). The trypanosomes (arrows) in Anti-RbTub (E) or pre-immunization serum (1) did not fluorescence at all. Abbreviations: nThTub=native T. brucei tubulin; dThTub=denatured T. brucei tubulin; STP12=synthetic tubulin peptide 12; RbTub=rat brain tubulin.
[0038] [0038]FIG. 9 illustrates the neutralization of the trypanosome inhibitory activity of anti-Trypanosome tubulin (anti-NTP) or anti-tubulin peptide (anti-STP) immune sera by SDS-PAGE purified trypanosome tubulin (dNTP). Trypanosomes were cultured in the presence of pre-immune serum (control), or anti-NTP serum pre-incubated with dNTP (dNTP-T), or anti-NTP serum not pre-incubated with dNTP (dNTP-UT), or anti-STP serum pre-incubated with dNTP (dNTP-T) or anti-STP serum not pre-incubated with dNTP (dNTP-UT). Trypanosome cell counts were made after 24 hrs using an improved Neuber hemocytometer and expressed as cells per 100 μl of incubation medium.
DETAILED DESCRIPTION OF THE INVENTION
[0039] [0039] Trypanosoma brucei tubulin was purified in its native state or after SDS-PAGE (denatured tubulin) and used to immunize mice or rabbits. Synthetic tubulin peptides (STP) and rat brain tubulin were also used. Immunized mice were challenged with the homologous or heterologous strains of T. brucei or T. congoletise or T. rhodesiense . The rabbit immune sera were used for in vitro trypanosome inhibition studies. Native T. brucei tubulin (nThTub) induced protection in all mice tested of which 60-80% (n=81) were complete protection (mice never became patent) and the remainder partial protection (mice became patent but lived longer than the controls). Not only did the nThTub protect against the homologous strain of T. brucei , but it it evoked an equally effective protection against heterologous strains of T. brucei, T. congolense and T. rhodesietise . However, the denatured T. brucei tubulin (dThTub) or synthetic tubulin peptides (STP) did not protect mice against trypanosome challenge, although the rabbit anti-dThTub or anti-STP sera did inhibit trypanosome growth in culture, but to a lesser extent than the anti-nThTub. The rat brain tubulin (RbTub) did not protect mice against trypanosome challenge, nor did the rabbit anti-RbTub serum inhibit trypanosome growth in culture. The levels and specificity of the induced antibodies were investigated by ELISA and Western blot. nThTub immunization by the subcutaneous route and the intraperitoneal route produced similar high levels of protection and antibody titres. dThTub and STP induced lower levels of antibody response than the nThTub. In Western blots the anti-nThTub, anti-dThTub and anti-STP antibodies recognized the tubulin in extracts from different trypanosome species or strains but not mammalian or chicken tubulin whereas antibodies raised against rat brain tubulin recognised trypanosome and vertebrate tubulin. Of five mice passively given immune sera from a group of mice immunized with nThTub at the minimal effective dose, four were protected while one became patent and died, but lived longer than the controls. This suggests that the protection observed may be humoral. The denatured tubulin and synthetic peptides failed to protect mice; probably because they were less immunogenic (produced much lower antibody response) than the native tubulin. The failure of the rat brain tubulin (RbTub) to cause immunoprotection in mice or the failure of the rabbit anti-RbTub sera to inhibit trypanosomes in culture suggests that the protection is parasite specific and is unlikely to cause an autoimmune reaction. An immunofluorescence test showed that the intact trypanosomes in vitro were not stained (except at a small spot in the flagella pocket region) by any of these antibodies but those that had been permeablised with Triton™-100, were specifically and uniformly labelled by the anti-trypanosome tubulin antibodies. The lack of specific immunofluorescence staining of the trypanosome surface suggests that the variant surface glycoproteins (VSG) did not take part in the immunoprotection. Overall these data suggest that tubulin is a novel and very promising target for the development of a parasite specific, broad spectrum anti-trypanosomiasis vaccine.
[0040] Materials and Methods
[0041] Animals and Trypanosome Stocks
[0042] Swiss mice and white giant rats were obtained courtesy of the Uganda Virus Research Institute, Entebbe and were provided with food and water ad libitum. New Zealand white rabbits (about 8 weeks old) were purchased locally and similarly fed. Trypanosome stocks were kindly provided by Dr. J. C. Enyarn of the Livestock Research Institute (formerly UTRO) Tororo, Uganda and included: two T. brucei stocks (UTRO 010291B and 220291D), one T. rhodesiense stock (UTRO 080291B) and one T. congolense (UTRO 161098B) stock. These stocks were maintained in liquid nitrogen or were propagated in mice or rats.
[0043] Harvesting of Trypanosomes for Tubulin Purification
[0044] Infected blood from liquid nitrogen was intraperitonealy inoculated into rats. Infection was confirmed by examination of tail blood and parasitaemia estimated by the Marching Method. Blood was collected from those rats with high parasitaemia (about 107/ml) and trypanosomes harvested from it by DEAE 52-cellulose (Sigma) anion exchange. The eluted trypanosomes were pelleted by centrifugation for 10 min at 3,000 g at 4° C. and washed twice by suspension in PEM buffer (100 mM pipes, 1 mM EGTA, 1 mM MgSO 4 , 1 mM PMSF, pH 6.9) followed by re-centrifugation as described above. The harvested trypanosomes were stored in liquid Nitrogen until needed for tubulin purification.
[0045] Tubulin Purification
[0046] Tubulin was purified from one strain of T. brucei (UTRO 010291B). Trypanosomes were mixed with 106 μm glass beads (Sigma) and disrupted for 15 min on ice with a pestle and mortar. The homogenate was then suspended in PEM buffer and centrifuged for 10 min at 3,000 g, 4° C. to pellet the beads and any undisrupted cells. The pellet was then re-homogenized to disrupt any remaining trypanosomes and the above procedure repeated twice to ensure that most cells were disrupted. The various homogenate fractions were pooled and centrifuged for 10 min at 10,000 g, 4° C. to remove the insoluble debris which were discarded and the supernatant further centrifuged for 1 h at 100,000 g, 4° C. The resulting supernatant was incubated for 1 h at 37° C. in the presence of 2 μ/ml taxol to promote tubulin polymerization and then centrifuged for 1 h, at 100,000 g, 25° C. The pellet containing the tubulin polymer was then solubilized in urea and renatured as described below.
[0047] Solubilization and Naturation of Tubulin
[0048] The tubulin, purified as above, was solubilised as previously described (Lubega, G. W. et al. (1993) Molecular and Biochemical Parasitology, 62: 281-292) of a described procedure. Briefly the pellet was dissolved in 3 ml 8 M urea and incubated at 25° C. for 1 hr and then diluted about 20 times with alkaline buffer pH 10.7 (50 mM KH 2 PO 4 , 0.1 mM PMSF, 1 mM EDTA and 50 mM NaCl) and incubated for a further 30 min. The pH was then adjusted to 8.0 and the supernatant concentrated to one third by ultrafiltration in CF50A membrane cones (Amicon) and re-diluted 3 times with MES buffer (0.025 MES, 1 mM EGTA, 0.5 mM MgSO 4 , 1 mM GTP, pH 6.0). This was again concentrated to one third and rediluted in MES buffer as described above and this was repeated twice. The final volume was centrifuged for 2 h at 40,000 g, 4° C. to ensure that there was no aggregated tubulin. The purified, renatured tubulin (hereafter referred to as native tubulin) was then stored in liquid nitrogen until needed for immunization and related studies.
[0049] Purification of Mammalian (Rat-Brain) Tubulin
[0050] The purification of tubulin from rat brain was done by the temperature dependent polymerization and depolymerization method (Shelanski, M. L. et al. (1973) Proceedings of the National Academy of Science of the United States of America, 70: 765-768).
[0051] Determination of Tubulin Concentration
[0052] Tubulin concentration was determined by the BioRad dye method using bovine serum albumin as standard.
[0053] Analysis of the Tubulin Purity and Identify
[0054] To estimate the purity of the tubulin to be used in immunizations, a solubilized sample of native tubulin was run on a 10% polyacrylamide gel utilizing a BioRad Mini-protean II electrophoresis cell as described (Lubega, G. W. and Prichard, R. K. (1991) Haemonchus contortus. Molecular and Biochemical Parasitology, 47: 129-138). The gel was processed for Western blot or stained with Coomassie blue and dried using a gel drier (1BioRad) and photodocumented using a MP4 camera system (Sigma).
[0055] For Western blot, the protein was transferred to a nitrocellulose membrane (BioRad) using the Mini-Transblot system and protocol (BioRad). The Western blot was performed as described (Lubega, G. W. and Prichard, R. K (1991) Haemooizcus contortus. Molecular and Biochemical Parasitology, 47: 129-138) using mouse anti-chicken tubulin monoclonal antibody (Amersham) and peroxidase-conjugated anti-mouse IgG (Jacksons Immuno research laboratories Inc, Canada). The substrate was 1.3 μM diaminobenzidine containing 0.02% (v/v) H 2 O 2 .
[0056] Recovery of Tubulin From the SDS-PAGE Gel for Immunization
[0057] To increase the purity of tubulin samples, tubulin bands were recovered from the SDS-PAGE gel. After SDS-PAGE, the tubulin band was identified using guide strips that were cut from both sides of the gel and stained. The piece of gel containing the tubulin band was sliced out and homogenised in PBS buffer using a polytron homogenizer. A little more buffer was added and the mixture stirred at 4° C. The supernatant was transferred to a dialysis tubing of 50 KDa exclusion limit (Spectrum Medical Instruments, USA) and dialysed overnight against PBS at 4° C. to remove the small ions. The tubulin solution was concentrated using ultrafiltration cones (Amicon) and kept in liquid nitrogen until required for analysis or immunization studies.
[0058] Synthetic Peptides
[0059] Two synthetic tubulin peptides (STh) corresponding to the carboxyl terminal of the β-tubulin CDNA (Kimel, B. et al. (1985) Gene, 35: 237-248) of T b. rhodesiense were ordered from the Sheldon Biotechnology Centre (McGill University, Canada). The STP 12 peptide with 12 amino acids (TEEEGEFDEEQY) was obtained already coupled to Key Hole Limpet Haemocyanin (KLH) whereas the STP 14 peptide with 14 amino acids (TIEEEGEFDEEEQY) was KLH-coupled in our laboratory using glutaraldehyde. Immuno-protection studies in mice
[0060] a) Immunization Studies
[0061] In order to determine whether immunization with tubulin would confer any protection and to establish a baseline for subsequent studies, an immunization and challenge experiment was performed. Briefly, mice were immunized subcutaneously with 40 μg and boosted with 20 kg and again with 20 μg of the native T. brucei tubulin or synthetic tubulin peptides at day 15 and day 30, respectively. For the initial immunizations, each of the antigens were added to an equal volume of Freund's complete adjuvant (FCA) and emulsified using a syringe and 22-gauge needle. Boosting was done using antigen emulsified in incomplete Freund's adjuvant (IFA). A control immunized with only adjuvant emulsified in PBS was similarly established. Mice were then challenged intraperitoneally with an otherwise lethal dose (10 3 cells in 200 μl PSG) of the homologous strain of T. brucei (UTRO 0120291B). Parasitaemia was monitored daily for the first month and then every three days thereafter and the patent period (days post-challenge when parasites first appeared in tail blood) was determined for each mouse. The persistence span (days post-challenge when each infected mouse died) and the protection rate (percentage of mice which did not become patent and survived beyond 60 days post challenge) were also determined.
[0062] Further experiments were set up to (i) investigate the effect of the dose, adjuvant and route of immunization (Table 1A), (ii) compare immunizations using either native or denatured trypanosome tubulin, mammalian tubulin or synthetic tubulin peptides (Table 1B) and (iii) to study the response to heterologous challenge (Table IC). In each experiment, parasitaemia was monitored daily for the first month and every three days thereafter. The patent period, persistence span and the protection rate were determined.
TABLE 1 Immunization regimes (a): Regime for determining the effects of dose, adjuvant and route of administration on efficacy of immunization with native tubulin (nTbTub). Mice were immunized subcutaneously or intraperitoneally with native tubulin from stock UTRO 01202291B with or without adjuvant followed by subsequently challenged with the homologous strain. Dose (mg) at day Antigen* mice (n) 0 15 30 Route* nTbTub 15 40 20 20 s/c nTbTub 15 40 20 20 i/p nTbTub 10 20 20 20 s/c nTbTub No adj 10 40 20 20 s/c Control 10 — — — s/c *Abreviations: nTbTub; Native tubulin derived from T. brucei UTRO 020191B nTbTub No Adj nTub administered without adjuvant Control Adjuvant (Complete or incomplete Freund's adjuvant) s/c; Subcutaneous route of immunization i/p; Intraperitoneal route of immunization (b): Regime for comparison of native or denatured trypanosome tubulin, mammalian tubulin, and synthetic tubulin peptides for immunization. Mice were immunized subcutaneously with the optimal dose of the antigen indicated and subsequently challenged with the homologous strain. Dose (mg) at day Antigen* mice (n) 0 15 30 nTbTub 15 40 20 20 dTbTub 10 40 20 20 RbTub 10 40 20 20 STP14 10 100 50 50 Control 10 — — — *Abbreviations: nTbTub; Native tubulin derived from T.brucei UTRO 020191B dTbTub Denatured TbTub recovered from SDS-PAGE gel STP 14; Synthetic tubulin peptide (STP14) based on T. rhodesiense b-tubulin c-DNA TbTub; Rat brain tubulin Control Adjuvant (Complete or incomplete Freund's adjuvant) (c): Regime for determining the efficacy of immunization with native T. brucei tubulin against homologous and heterologous challenge. Mice were immunized subcutaneously with the previously determined optimal dose of native tubulin from T. brucei stock UTRO 010291B and challenged with a lethal homologous or heterologous stock. A lethal dose of T. brucei = (10 3 cells), T. rhodesiense or T. congolense (both) = (10 5 cells). Dose (mg) at day Antigen* mice (n) 0 15 30 Challenge stock # nTbTub 15 40 20 20 T.b 010291B Control 10 — — — T.b 010291B nTbTub 15 40 20 20 T.b 220291D Control 10 — — — T.b 220291D nTbTub 15 40 20 20 T.r 080291B Control 10 — — — T.r 080291B nTbTub 15 40 20 20 T.c 161098B Control 10 — — — T.c 161098B *Abbreviations: nTbTub; Native tubulin derived from T. brucei UTRO 010291B Control Immunized with adjuvant (Complete or incomplete Freund's adjuvant) T.b; Trypanosoma brucei T.c; Trypanosoma congolense T.r; Trypanosoma rhodesiense # The trypanosome stocks are denoted with a UTRO number
[0063] b) Passive Transfer of Immune Sera
[0064] Immune sera, 100 μl, from the protected group or pre-immunization sera from the control (unimmunized mice) were administered intravenously into naive irradiated mice. The mice were then challenged with a lethal dose of trypanosomes after 1 hr and monitored for protection as described above.
[0065] c) Sub-Inoculation of Mice with Brains from the Protected Mice
[0066] In order to establish whether the protected mice were sterile (completely free of trypanosomes) mice that did not show parasitaemia by day 60 were sacrificed and the brains dissected out and washed twice in PSG. They were cut into small pieces with a scalpel and teased out and centrifuged at 3,000 g for 10 minutes and the pellet resuspended in PSG. The 200 μl of this suspension was administered intraperitoneally into naive irradiated mice and the mice monitored for parasitaemia
[0067] d) Evaluation of the Level and Specificity of Antibody Responses
[0068] In order to determine the rate of development of the antibody response, following the subcutaneous and intraperitoneal route of immunization, blood was collected from the retro-orbital sinuses of mice at day 14, 21, 28 and 35 post immunization and the serum obtained and stored at −20° C. until used in ELISA and Western blot assays to study the level and specificity of the antibodies generated. Similarly, the development of the antibody responses to STP14 and nThTub were compared over time. Peak antibody responses for all the antigens were also compared at day 35 post-imrnunization.
[0069] The poly-L-lysine based ELISA (Lubega, G. W. and Prichard, R. K. (1991) Haemonchus contortus. Molecular and Biochemical Parasitology, 47: 129-138) was used to compare the antibody levels. For ELISA, each anti-serum was measured against nThTub, dThTub, RbTub or STP14 as antigen.
[0070] The Western blot was performed as described above to demonstrate clearly the specificity of the antisera produced in mice. For Western blot, total soluble extracts of T. brucei UTRO 010291B, T. rhodesiense UTRO 080291B, T. congolense UTRO 161098B and rat brain were run on 10% SDS-PAGE gel and transferred to nitrocellulose membrane and probed with the antisera against nThTub, or dTbTub (both derived from UTRO 010291B), or STP14 or RbTub derived from rat brain
[0071] f) Statistical Analysis
[0072] Data on protection were presented as means±standard errors of the mean (SEM). Significant differences (p-values) were determined by comparison of means by Student's t test or analysis of variance (ANOVA) or comparison of proportions where applicable.
[0073] Trypanosome Viability Studies Against Rabbit Immune Serum in Culture
[0074] a) Rabbit Immune Serum
[0075] In order to obtain sufficient amounts of serum for in vitro inhibition studies, parallel immunizations were performed in rabbits. About 100 μg of T. brucei or rat brain tubulin or synthetic peptide were solubilized in PBS pH 7.4 in a total volume of 0.5 ml and emulsified in an equal volume of Freund's complete adjuvant. Blood for the preparation of pre-immunization serum was drawn from the marginal ear vein after which the uniform emulsion (1 ml) was injected intradermally into one rabbit at multiple sites. After two weeks each rabbit was boosted with 50 μg of the same antigen emulsified in Freund's incomplete adjuvant. A second boost was performed in a further two weeks. Blood for preparation of the immune serum was drawn from the marginal ear vein, seven days after the last boost. The serum was diluted with an equal part of 5% (w/v) BSA in PBS pH 7.4 and stored at −20° C. until needed. The production and specificity of the antibodies in rabbit serum were determined using ELISA and Western blot as described above, before being used for trypanosome viability studies in culture.
[0076] b) Trypanosome Inhibition Assay in Culture
[0077] The assay was run in a 96-well plate. For short term assays (24 h) a high seeding density (2×10 5 cells per ml) was applied, while for the long term assays (4-10 days), a low density (4×10 3 cells per ml) was applied. The immune serum (containing an equal volume of 5% BSA) was diluted with an equal volume of complete bloodstream-form trypomastigote medium (CBM) (Baltz, T. et al. (1985) EMBO Journal 4: 1273-1277) and 75 μl of it added in duplicate into wells of column 11 of a 96-well tissue culture plate (T?P, Switzerland). CBM (50141) was then added to all the wells to be used in columns 2 to 10. Serial dilutions were then begun by transferring 25 μl from the appropriate wells of column 11 serially down to column 4. The 25 μl drawn from column 4 were discarded leaving wells of column 2 and 3 as control.
[0078] Pre-immunization serum was run in parallel with each immune serum. A suspension of trypanosomes previously culture-adapted by continuous growth in culture for at least 3 weeks was then diluted with CBM to give the required cell density per ml and 50 μl of it added into each well already containing the test or control samples. Wells of column 1 and 12 were not inoculated with trypanosomes but were filled with blank CBM to guard against evaporation from the outermost assay wells.
[0079] The plates were incubated at 37° C. under, 5% CO 2 and observed under an inverted microscope for growth characteristics and numbers every 24 hrs. For the long term assay, the medium was changed every 48 hrs, care being taken not to remove the trypanosome cells at the bottom of the wells. Trypanosome cells in each well were counted every 24 hrs using an improved Neumbeur haemacytometer.
[0080] c) Immuno-Agglutination Test
[0081] In order to determine whether antibodies could be involved in the mechanism of growth inhibition in vitro, an immuno-agglutination test was performed using the various immune sera and pre-immunization serum as control. Serum diluted with an equal part of 5% (w/v) BSA in PBS (pH 7.4) was added to a culture of trypanosomes in the log phase of growth in a 24-well culture plate and incubated for 30 min at 37° C. under 5% CO 2 and observed for agglutination under a microscope.
[0082] d) Immunofluorescence Test
[0083] To determine whether the antibodies were recognizing a surface or internal antigen, immunofluorescence tests were performed in two ways. The first test was performed on a suspension of intact trypanosomes in 1.5 ml microfuge tubes. The trypanosomes were treated with 1% (v/v) formaldehyde in PBS (pH 7.4) at 4° C. for 10 min, followed by washing (3-5 min) with PBS-G (0.1% (w/v) glucose in PBS) and centrifugation at 3000 rpm, 4° C. for 5 min. The pellet was incubated with 10% (w/v) fetal calf serum in PBS for 15 min to block non-specific antibody binding. After washing and centrifugation, the pellets were resuspended in PBS-G and equal volumes of antisera added and incubated for 1 hr at 25° C. After washing the pellets were incubated with diluted fluorescein-conjugated protein A and washed again. The pellets were then seeded onto a glass slide and observed under a fluorescence microscope.
[0084] The second test was performed on fixed permeabilised trypanosomes. Here the trypanosomes were smeared onto glass slides and air dried, followed by fixing for 10 min. with acetone-methanol mixture, 1:1 (v/v) pre-cooled to −20° C. The slides were washed with PBS to rehydrate the cells. The trypanosomes were permeabilised using 1% (v/v) Triton™-X 100 in PBS. Blocking and incubation with sera and conjugated protein A were performed as for the intact trypanosomes. All washing of slides were done using PBS-G on a rocking shaker.
[0085] Results
[0086] Purification of Tubulin
[0087] Tubulin was purified to near homogeneity and only one band corresponding to tubulin at 55 KDa was visible on SDS-PAGE gel stained with Coomassie blue (FIG. 1). To confirm that this band was tubulin a similar gel was run and transferred to a nitrocellulose membrane and probed with anti-chicken tubulin monoclonal antibody. The monoclonal antibody reacted strongly with the trypanosome tubulin and the rat brain tubulin at around 55 IDa (FIG. 1).
[0088] Immunoprotection Studies
[0089] (a) Investigation of Protection by Native T. brucei Tubulin and Tubulin Subunit Peptides in Mice
[0090] Native T. brucei tubulin (nThTub) was used to immunize mice which were subsequently challenged with the homologous strain of T. brucei . A total dose of 80 μg (nThTub) administered in 3 phases as described in Materials and Methods, was able to confer 100% protection to mice of which 67% (n=6) were completely protected (did not become patent at all) whereas the remaining 33% were partially protected since their patent period and persistence span were higher (p<0.05) than the controls (Table 2). A similar or even higher dose of synthetic peptides (STP12 or 14) did not confer any protection. Since there were no differences between the two peptides (STP12 and STP14) and only one of these peptides was used in subsequent experiments.
TABLE 2 Effects of immunization with native T. brucei tubulin and synethetic peptides derived from T. brucei rhodesiense tubulin Mice were immunized subcutaneously with the native T. brucei tubulin (nTbTub), synthetic peptides (STP12 or 14), or with adjuvant alone emulsified in PBS (control). All the mice were challenged with the strain (UTRO 010291B) homologous to the nTbTub. The patent period (number of days post-challenge when parasites first appeared in tail blood) was determined for each mouse and the mean calculated for the patent mice. The persistence span (mean number of days post-challenge when the patent mice died) and the protection rate (percentage of mice surviving beyond 60 days post challenge) were also determined. Mean Patent Mean Patent Persistence Protection Antigen rate (%) a period ± SEM b Span ± SEM c Rate (%) d Control 100 4.6 ± 0.5 7.5 ± 0.5 0 STP12 100 4.1 ± 0.4 6.5 ± 1.0 0 STP14 100 4.3 ± 0.8 7.1 ± 0.8 0 nTbTub 33* 6.0 ± 0.5** 13.2 ± 1.5** 67**
[0091] b) Effect of nTbTub Dose and Adjuvant on Protection
[0092] Of the mice immunized using the 40, 20, 20 kg regime by the subcutaneous route, 40% (n=15) developed parasitaemia but were partially protected since their mean patent period and persistence span were significantly higher (p<0.05) than the control (Table 3). The rest (60%) did not develop parasitaemia at all and were completely protected from the challenge. Sub-inoculation of their brains into naive irradiated mice showed that they were completely parasite free. However, when the immunizing dose was halved (20, 10, log regime) all the mice (100%) developed parasitaemia and died, although their persistence span and patent rates were significantly higher (p<0.05) than the controls. Therefore, the 40, 20, 20 μg regime was considered to be the minimum effective dose. It should be noted that all the mice immunized with this dose but without adjuvant, developed parasitaemia and died with no significant differences from the controls (p>0.05) in their patency rate and persistence span.
TABLE 3 Effect of nTbTub dose or adjuvant on protection Mice were immunized subcutaneously with the nTbTub at a total dose of 80 μg (administered as 40, 20, 20 μg) or 40 μg (administered as 20, 10, 10 μg) in adjuvant or 80 μg but without adjuvant and a control (mice injected with adjuvant emulsified in PBS) included. All the mice were challenged with the strain (UTRO 010291B) homologous to nTbTub. The patent period (number of days post-challenge when parasites first appeared in tail blood) was determined for each mouse and the mean calculated for the mice that became patent. The persistence span (mean number of days post-challenge when the patent mice died) and the protection rate (percentage of mice surviving beyond 60 days post challenge) were also determined. Mean Amount of Patent Mean Patent Persistence Protection Antigen rate (%) a period ± SEM b Span ± SEM c Rate (%) d Control (0 μg) 100 3.6 ± 0.5 6.8 ± 0.8 0 40 μg 100 6.8 ± 0.5** 12.8 ± 1.1** 0 (in Adjv.). 80 μg 40* 6.0 ± 0.5** 13.2 ± 1.5** 60** (in Adjv.) 80 μg 100 3.5 ± 0.2 7.0 ± 0.5 0 (no Adjv.)
[0093] c) Effect of Route of Immunization
[0094] Only 27% or 40% (n=15) of the mice became patent following immunization with nThTub via the intraperitoneal or subcutaneous routes, respectively. The remaining 73% and 60%, respectively, did not become patent and were completely protected from infection beyond 60 days post challenge (Table 4). The mice which became patent were partially protected since they became patent later and survived longer (p<0.05) than the control mice. Based on these parameters (patency rate, persistence span and protection rate) there was no significant difference (p>0.05) between the intraperitoneal and subcutaneous routes of immunization and therefore the subcutaneous route was used in subsequent experiments.
TABLE 4 Effect of route of immunization on protection Mice were immunized with nTbTub (80 μg) either subcutaneously (SC) or intraperitoneally (IP) and challenged with the strain (UTRO 010291B) homologous to nTbTub. The control were inoculated with adjuvant emulsified in PBS. The patent period (number of days post-challenge when parasites first appeared in tail blood) was determined for each mouse and the mean calulated for the mice that became patent. The persistence span (mean number of days post-challenge when the patent mice died) and the protection rate (percentage of mice surviving beyond 60 days post challenge) were also determined. Mean Patent Mean Patent Persistence Protection Antigen rate (%) a period ± SEM b Span ± SEM c Rate (%) d Control 100 3.6 ± 0.5 6.8 ± 0.8 0 SC 40* 6.0 ± 0.5** 13.2 ± 1.2** 60** IP 27* 7.3 ± 0.9** 16.5 ± 1.0** 73**
[0095] d) Comparison of the Protection Due to nThTub, dbTub, RbTub and STP Antigens
[0096] Mice immunized with dThTub, RbTub or STP14 were not protected since there was no significant difference (p>0.05) in patent period, persistence span, or the protection rate between any of these groups and the control (Table 5). However for the mice immunized with nTbTub, 60% were completely protected and did not become patent throughout the experiment. The remaining 40% were partially protected since their patent and persistence periods were significantly higher (p<0.05) than the controls.
TABLE 5 Comparison of native and denatured T. brucei tubulin, mammalian tubulin and a synthetic tubulin peptide Mice were immunized subcutaneously with the native (nTbTub), or denatured trypanosome tubulin derived from SDS-PAGE gel (dTbTub), or native tubulin from rat brain (RbTub), synthetic peptide (STP14), or a control (adjuvant emulsified in PBS). All the mice were challenged with the homologous strain, Trypanosoma brucei (UTRO 010291B). The patent period (number of days post- challenge when parasites first appeared in tail blood) was determined for each mouse and the mean calculated for the mice that became patent. The persistence span (mean number of days post-challenge when the patent mice died) and the protection rate (percentage of mice surviving beyond 60 days post challenge) were also determined. Mean Patent Mean Patent Persistence Protection Antigen rate (%) a period ± SEM b Span ± SEM c Rate (%) d Control 100 3.6 ± 0.5 6.8 ± 0.8 0 STP14 100 3.7 ± 0.6 6.8 ± 0.7 0 RbTub 100 3.4 ± 0.5 7.2 ± 1.0 0 dTbTub 100 3.5 ± 0.2 6.9 ± 0.2 0 nTbTub 40* 6.0 ± 0.5** 13.2 ± 1.5** 60**
[0097] e) Protection Against Heterologous Challenge
[0098] Mice were immunized subcutaneously with the minimum effective dose of native trypanosome tubulin (nThTub) and challenged with either T. congolense or T. rhodesiense or a different strain of T. brucei . There was protection observed against all of these strains of trypanosomes. In the group of mice challenged with a strain of T. brucei different from the one from which the immunogen was derived, only 36% (n=15) of the mice developed parasitaemia while 64% were completely protected and never developed any parasitaemia. For the 36% that developed parasitaemia, their patency period and persistence span were significantly higher than the control (p<0.05). In the groups challenged with T. congolense and T. rhodesiense, 73% (n=15) in each group were completely protected and never developed any parasitaemia (Table 6). The remaining 27% developed parasitaemia in each group but their patency period and persistence span were higher (p<0.05) than their controls. There was no significant difference (p>0.05) in the level of protection between the groups challenged with different species or strain.
TABLE 6 Protection against heterologous challenge Mice were subcutaneously immunized with native T. brucei tubulin (nTbTub) derived from strain UTRO 010291B and challenged with a heterologous strain of T. brucei (UTRO 220291D) or with T. rhodesiense (UTRO 080291B) or T. congolense (UTRO 161098B). A control injected with adjuvant emulsified in PBS was included. The patent period (number of days post-challenge when parasites first appeared in tail blood) was determined for each mouse and the mean calculated for the mice that became patent. The persistence span (mean number of days post-challenge when the patent mice died) and the protection rate (percentage of mice surviving beyond 60 days post challenge) were also determined. Mean Protection Patent Mean Patent Persistence rate Challenge stock Antigen rate (%) a period ± SEM b Span ± SEM c (%) d T. brucei Control 100 3.6 ± 0.5 6.8 ± 0.8 0 (UTRO 010291B) nTbTub 40* 6.0 ± 0.5** 13.2 ± 1.5** 60** T. brucei Control 100 6.5 ± 0.4 9.8 ± 1.8 0 (UTRO 220291D) nTbTub 36* 8.6 ± 0.7** 17.6 ± 0.8** 64** T. rhodesiense Control 100 10 ± 0.4 36.0 ± 4.3 0 (UTRO080291B) nTbTub 27* 12.2 ± 0.6** 46.4 ± 5.4** 73** T. congolense Control 100 5.0 ± 0.3 32.6 ± 4.0 0 (UTRO161098B) nTbTub 27* 9.8 ± 0.9** 45.5 ± 2.9** 73**
[0099] f) Passive Transfer of Immunity
[0100] Five mice were passively given immune sera, and subsequently challenged with the homologous T. brucei UIRO 020191B strain. Only one (20%) developed parasitaemia but it died later than control mice who did not receive immune sera, but were similarly challenged. There was no parasitaemia detected in the other four (80%) mice given immune sera, after the 60 days of monitoring.
[0101] g) Rate of Antibody Development: Effect of Route of Immunization and Synthetic Tubulin Peptides
[0102] Mice were immunized with nThTub subcutaneously or intraperitoneally and the antibody responses over time determined by ELISA (FIG. 2). There were no significant differences (p>0.05) between the two routes of immunization in the level or rate of development of the antibody response. At the same time another group of mice was immunized subcutaneously with synthetic peptide (STI14) and the antibody responses over time compared with that due to nThTub. The level or rate of development of the antibody response due to STP14 was much lower than that due to nThTub and remained so throughout the experiment despite the various immunization boosts (FIG. 2).
[0103] h) Evaluation of Antibody Specificity by Western Blot
[0104] Coomassie staining of crude extracts from different trypanosome strains and rat brain following SDS-PAGE (FIG. 3, Panel A) revealed the presence of a variety of proteins in each extract. Antibodies raised against rat brain tubulin specifically recognized both mammalian and trypanosome tubulin of all the species and strains studied (FIG. 3, panel B). All the anti-trypanosome tubulin (whether anti-native, -denatured or -peptide) sera specifically recognized a single band corresponding to trypanosome tubulin on SDS-PAGE gel (FIG. 3), irrespective of species or strain, but did not recognize rat brain tubulin (FIG. 3, Panel C, D, and E). Pre-immunization sera failed to recognize any antigen (FIG. 3, Panel F).
[0105] i) Evaluation of the Antibody Levels and Specificity by ELISA
[0106] The various antisera raised against different antigens were compared by ELISA for specificity and antibody levels (FIG. 4). The specificity of the sera by ELISA was similar to that observed in Western blots. In particular, the anti-trypanosome sera (anti-nThTub, -dThTub and -ST 14) did not recognise rat brain tubulin but the anti-rat brain tubulin antibodies did recognise all the trypanosome tubulins, except the synthetic peptides, whereas the anti-nThTub and anti-dThTub did recognise the trypanosome tubulin including the peptides (FIG. 4). Although there were cross reactions, the amplitude of the reactions was strongest against self antigens in all cases.
[0107] In vitro Studies Using Sera From Immunized Rabbits
[0108] a) Specificity of the Rabbit Immune Serum
[0109] The specificity and antibody response patterns, using immune sera raised in rabbits against trypanosome tubulins, produced similar ELISA and Western blot results as those obtained with the corresponding mouse immune sera. For example, in Western blots, the rabbit anti-nThTub, anti-dTbTub and anti-STP serum specifically recognised trypanosome tubulin but not rat or chicken brain tubulins. However, the rabbit anti-rat tubulin serum recognised rat brain tubulin but not trypanosome tubulin.
[0110] b) Trypanosome Inhibition in Culture
[0111] Pre-immunization rabbit serum diluted 10 times or more had no effect on trypanosome growth. Therefore, all test sera were diluted at least 10 times and compared with the pre-immunization serum diluted 12 times. The anti-nThTub serum strongly inhibited trypanosome growth in culture and the inhibition effect decreased with increasing dilutions but increased with incubation-time such that by day 8 even serum diluted by nearly ×1000 visibly reduced trypanosome growth. In contrast, the pre-immunization serum diluted 12 times did not affect trypanosome viability (FIG. 5). A similar pattern was observed for the anti-dTbTub, anti-STP12 or anti-STP14 sera in that the inhibition of trypanosome growth was affected in a dilution and incubation-time dependent manner as described above. However, the percentage inhibition for these anti-sera was less than for the anti-nThTub serum at the equivalent dilutions and incubation times (FIG. 6). The rank order of activity of the sera was: nThTub>>dThTub>STP12=STP14 and appeared to correlate with the rank order of the antibody levels observed by ELISA (see above).
[0112] c) Immunoagglutination test
[0113] The pre-immunization serum did not cause any agglutination of trypanosomes within the 30 min incubation time but there was pronounced agglutination with the anti-nThTub serum (FIG. 7). Even the free (non-agglutinated) trypanosomes in the culture incubated in the anti-nThTub serum were markedly deformed. Agglutination also occurred with the anti-dThTub and anti-STP sera but not with anti-rat brain tubulin. In addition, treatment with heat (56° C.), which inactivates complement, did not eliminate the agglutinating effect, where it occurred.
[0114] d) Immunofluorescence Test
[0115] There was intense and uniform fluorescence when the fixed permeablised trypanosomes were probed with the anti-nThTub, anti-dThTub or anti-STP12, but there was no fluorescence when anti-rat tubulin or pre-immunization sera were used (FIG. 8). However, when the intact trypanosomes were probed with any of the sera, except the anti-RbTub and the pre-immunization sera, there was fluorescence only in a small area near the posterior end of the trypanosomes.
[0116] Discussion
[0117] This study was carried out to explore whether tubulin would be a target for a vaccine against trypanosomiasis. In particular it was to investigate (i) whether immunization of mice with tubulin or synthetic peptides of tubulin could confer any protection, (ii) to determine the conditions under which such protection would occur and (iii) to establish whether rabbit anti-tubulin or anti-tubulin peptide sera would alter the viability of trypanosomes in culture.
[0118] Tubulin was purified from one strain of T. brucei and analyzed for purity before being used to immunize mice or rabbits. Only a single band around 55 KDa was observed, after staining with Coomassie blue, which corresponded with tubulin purified from rat brain. Both were recognized by commercial anti-chicken tubulin monoclonal antibodies (Amersham) in Western blots (FIG. 1).
[0119] In the experiments in which mice were immunized with the native T brucei tubulin and challenged with a lethal dose of trypanosomes, between 60 and 80% (n=81) were completely protected without becoming patent, whereas the remaining mice were partially protected with longer patency and persistence spans than the controls. Tubulin from T. brucei (UTRO 010291B) not only protected against challenge with a homologous strain of T. brucei but also against challenge with a heterologous strain of T. brucei or T. congolense or T. rhodesiense (Tables 4-8). This is interesting because it suggests that the variable surface glycoprotein (VSG) was not responsible for the immunoprotection observed The VSG only protects against the homologous unpassaged challenge (Scott et al., 1978). This means that trypanosome tubulin from one strain can confer protection against many strains and species. The mechanism by which the protection in this study occurred seems to have been antibody mediated since passive transfer of antibodies resulted in protection against challenge. We are the first to report that tubulin, the principal microtubule protein, can confer complete immunoprotection against trypanosomiasis.
[0120] Protection was reported against American trypanosomiasis ( T. cruzi infection) using the purified paraflagella rod protein (Wrightsman, R A. et al. (1995) Infection and Immunity, 63:122-125) or whole flagella fraction quiz, A. M. et al. (1990) Molecular and Biochemical Parasitology, 39: 117-126). Use of the purified paraflagella rod protein did not prevent infection in any mice but the parasitaemia was reduced and all the mice survived up to 120 days (Wrightsman, R A. et al. (1995) Infection and Immunity, 63:122-125). However, the paraflagella rod protein has not been tried in African trypanosomiasis. Use of the whole flagella fraction against T. crui resulted in 60% of the mice being completely protected without any parasitaemia and the remaining 40% becoming partially protected, but immunization with the flagella pocket fraction against African trypanosomiasis resulted in partial protection only (Mkunza, F. et al. (1995) Vaccine, 13: 151-154). The other study in which complete protection was reported involved immunization with a fraction containing MAP 52 and two glycosomal enzymes and resulted in 100% complete protection without any mouse becoming patent upon challenge with trypanosomes (B3alaban, N. et al. (1995) Journal of Infectious Diseases, 172: 845-850). It is interesting that both tubulin and these other protective fractions (flagella and MAP52) have some relationship with microtubules and the antibodies against these after protective antigens localized in the flagellum, the body of the parasite, the membrane, and the flagella pocket.
[0121] ELISA and Western blot studies showed that the antibodies against the T. brucei tubulin we used recognized tubulin of the other strains and species of trypanosomes studied (FIG. 3). It is therefore not surprising that mice were protected against challenge with heterologous strains of T. brucei and other species. Most of the subcellular antigens are non variable across species but their access to the host immune cells may be difficult because the VSG is not only abundant but very well exposed on the surface and is recognised at the expense of (out competes) the subcellular antigens. However, when these subcellular antigens are presented in pure form to the immune system, they can induce a strong and protective immune response. Therefore, whereas the immune recognition cells may not access the internal antigens, the antibodies they generate can be internalised, by a mechanism not yet established. It is possible that the flagella pocket can play a role in this internalisation process. It is known that antibodies play a significant role in controlling trypanosome infection and indeed, in this study, passive transfer of anti-tubulin serum to naive mice resulted in 80% complete protection, indicating that the protection observed was humoral. This was also confirmed by the serum inhibition studies whereby trypanosome proliferation in culture was specifically inhibited by the anti-tubulin antibodies (FIG. 5 & 6). It is suggested that parasites that replicate extracellularly, like the African trypanosomes, can be controlled by antibodies through one or more mechanisms. In one of these mechanisms, antibodies may bind these parasites and block their attachment to the host receptors and interfere with their entry and establishment in their predilection site. This can be the mechanism by which our mice that became protected never became patent. It is interesting that all the mice that became patent eventually died even though this took longer than the control, suggesting that the mice failed to clear the infection once it got established in the blood system. The reason for this is not clear since tubulin is incapable of antigenic variation However, it is possible that the antibody levels became depleted since the tubulin of the intact trypanosomes is unlikely be accessed by the host's immune recognition cells in order to boost the immune response. Alternatively, it may be related to the immunosuppressing ability of the established trypanosomes. On the other hand, the immune serum was able to inhibit trypanosome growth in culture where attachment receptors are not required. However, tubulin is involved in cell division via the mitotic spindle and other processes. It is possible that the antibodies blocked trypanosome cell division but other humoral-effector mechanisms such as agglutination, lysis and complement (Newman, M. J. et al. (1995) Immunological Formulation design considerations for subunit vaccines. In: M. F. Powell and M. J. Newman (ed) The Subunit and Adjuvant Approach . Plenum Press, New York) could have played a role in vivo. In this study the anti-trypanosome tubulin immune serum caused agglutination of trypanosomes in culture but non-immune serum or anti-rat brain tubulin serum did not (FIG. 7). However, lysis was not observed and this agglutination was not inactivated by pre-heating (56° C.) the serum suggesting that complement was not involved. Agglutination was probably caused, indirectly, by the internalized antibodies but not via cross-linking of surface bound antibodies since the immunoflorescence test did not reveal antibodies on the surface in this study or other studies (Balaban, N. et al. (1995) Journal of Infectious Diseases, 172: 845-850). It was proposed that stress due to the internalized antibodies can cause agglutination (Balaban, N. et al. (1995) Journal of Infectious Diseases, 172: 845-850). This study could therefore not conclusively establish the mechanism by which the antibodies caused the protection we observed.
[0122] Among the most interesting observations was that tubulin from one strain of T. brucei conferred protection against challenge from heterologous strains of the same or different species. Thus tubulin from one strain conferred a broad protection against African trypanosomiasis. Secondly, the anti-tubulin antibodies did not uniformly stain the surface of the trypanosomes in an immunofluorescence test (FIG. 8). They stained a small part of the posterior end which probably represents the region (flagella pocket) uncovered from the VSG coat. The heterologous protection and the antibody staining pattern conclusively rules out the involvement of the VSG in the protection.
[0123] β-tubulin rather than α-tubulin is primarily targeted by anti-tubulin drugs (Lubega, G. W. and Prichard, R. K. (1991) Haemonchus contortus. Molecular and Biochemical Parasitology, 47: 129-138). Therefore, in this study synthetic peptides from the most variable (i.e. unique for every organism) and immunogenic part of B-tubulin cDNA, the C-terminus (Kimmel, B. et al. (1985) Gene, 35: 237-248) were tested for their immunoprotection abilities. These peptides were not protective upon challenge, although they induced antibodies which recognised tubulin from all the trypanosomes tested but not mammalian tubulin (FIG. 3). It is possible that this failure was due to the fact that the peptides induced a much lower antibody level than the whole native tubulin (FIG. 4.). This was supported by a parallel study in culture whereby rabbit anti-peptide serum of exactly the same specificity, exhibited killing of trypanosomes but with much less effect than the anti-native tubulin antibodies at comparable dilutions (FIG. 6). Therefore a mechanism which can boost the levels of these anti-peptide antibodies in blood may render them protective. Alternatively, it is possible that these peptides, which contain only very short sequences from the C-terminal of β-tubulin, did not represent the protective epitopes. It would be interesting to know how the peptides from other regions of B-tubulin would behave and to substantiate the role of α-tubulin, if any. Alpha-tubulin might play a role, at least in the immune induction mechanisms, as it does to stabilise the benzimidazole (anthelmintic) binding site of nematode β-tubulin (Lubega, G. W. et al. (1993) Molecular and Biochemical Parasitology, 62: 281-292). These studies indicate that conformation might play a role in the immunogenicity of the protective epitope because whole tubulin isolated by SDS-PAGE (and denatured) induced a much lower level of antibody response (FIG. 4) and did not confer any protection to immunized mice on challenge. Again, the rabbit anti- T. brucei denatured tubulin antibodies exhibited killing of trypanosomes in culture but with much less effect than the anti-native antibodies at comparable dilutions (FIG. 6). Thus the level of antibodies (titre) and therefore the immunogenicity may have played a role in the tubulin immuno-protective ability. It would be interesting to express the ax and B-tubulin isoforms in a single and dimeric native state and use them in immunoprotective studies. This type of study is planned for the near future. A study involving overlapping peptides spread over the whole α or β-tubulin isoform is also planned in order to identify the protective epitope(s). Also required is a study to identify antigen-delivery mechanism or conditions that result in an optimal antibody response. A recombinant vaccine based on tubulin would be an interesting advancement for human and animal African trypanosomiasis control since 60-80% protection would result in a significant reduction in the transmission of trypanosomiasis. Mice immunized with the anti-rat brain tubulin died at the same time as the controls. Thus the protection was apparently specific to trypanosome derived tubulin; and despite tubulin being present in the host, immunization with trypanosome tubulin would probably not cause serious auto immune reactions. This is also supported by the fact that both rabbit and mouse anti-trypanosome tubulin antibodies recognised only tubulin in trypanosome but not mammalian soluble extracts.
[0124] We have presented for the first time, data which indicates that tubulin is a promising target for development of a parasite specific, broad-spectrum anti-African trypanosomiasis vaccine.
[0125] The present invention will be more readily understood by referring to the following example which is given to illustrate the invention rather than to limit its scope.
EXAMPLE I
Anti-Tubulin Antibody With Trypanocidal Activity
[0126] An experiment was set up to investigate whether a contaminating antigen is responsible for the immunoprotection by the native trypanosome tubulin (NTP). Previous data showed that whereas immunization with NTP was protective in mice, synthetic β-tubulin peptides (STP) from the variable and immunogenic C-terminal or denatured tubulin, purified by SDS-PAGE (dNTP) were not significantly protective in vivo. This raised the possibility interpretation that SDS-PAGE removed a contaminating antigen which could be responsible for the protection. However, it should be noted that all immune sera (anti-NIP, anti-STP or anti-dNTP) were trypanocidal when directly applied to trypanosomes in culture, although the anti-NTP was far more active (effective at much lower titre) than the anti-dNTP or anti-STP, and suggests that DNTP and STP may be immunogenic in vivo, but not sufficiently so to be protective.
[0127] In order to unequivocally demonstrate that antibody to trypanosome tubulin was the lethal component in the antisera raised against NIP or STP, anti-tubulin antibody was adsorbed using the SDS-PAGE purified denatured tubulin (dNTP) and the trypanocidal activity of the sera assessed.
[0128] Materials and Methods
[0129] Trypanosome tubulin was purified (NTP) and used to immunize rabbits as described previously. Synthetic peptides (STP) used previously were similarly used to raise immune serum. In both cases pre-immune and immune sera were collected and processed in the usual manner. The native trypanosome tubulin (NTP) was further purified by SDS-PAGE in order to remove any contaminating antigen. We previously described this preparation as denatured trypanosome (dNTP) and we used it in this experiment to determine if it would remove (adsorb) the anti-tubulin (NTP) or anti-STP antibodies and block their inhibition of trypanosome proliferation in culture.
[0130] Trypanosomes were cultured and the immune serum applied as previously described.
[0131] Results and Discussion
[0132] Treatment of the anti-NTP or anti-STP serum with dNTP completely abolished the trypanocidal activity of either serum (FIG. 9). The data indicates that the trypanocidal activity is due to anti-tubulin antibody and not an antibody to a contaminating antigen in the NTP.
[0133] While the invention has been described in connection with specific embodiments thereof, it will be understood that it is capable of further modifications and this application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth, and as follows in the scope of the appended claims.
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The present invention relates to the immunization of animals and humans with trypanosome tubulin to protect against trypanosomes. More particularly, the present invention relates to a substantially pure tubulin preparation, which comprises a tubulin extract from Trypanosoma brucei which tubulin preparation can protect animals and humans against heterologous strains of different species of Trypanosoma.
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BACKGROUND OF THE INVENTION
The present invention relates to a false twist crimping apparatus for crimping synthetic filament yarns and a method of threading the yarn thereon.
Machines of the described type are known from DE-OS 38 01 506.4. Also in the known machine, such as is described, for example in DE-OS 38 01 506.4, yarn guides are arranged at a distance from the yarn heating plate, into which the yarn is inserted for the purpose of threading. These yarn guides define an temporary position of the yarn path, in which the yarn is guided without contacting the heating plate.
The known machines are very well suited, when the heating plate faces the service aisle. However, DE-OS 38 01 506.4 also discloses such machines, in which the heating plate faces away from the service aisle, so that it is difficult to thread the yarn.
It is the object of the present invention to provide an apparatus and method for threading the yarn on the heating plate in a service-friendly manner and which permits the yarn to be readily threaded, and which is applicable in particular on machines having heating plates which face away from the service aisle.
SUMMARY OF THE INVENTION
The above and other objects and advantages of the present invention are achieved in the embodiments illustrated herein by the provision of a yarn heating apparatus which comprises an elongate yarn heating plate, cover means mounted for movement between a closed position covering the heating plate and an open position wherein the heating plate is uncovered, and yarn supporting means for supporting the yarn for advance along an temporary path of travel on the side of the cover means opposite the heating plate when the cover means is in the closed position, and for releasing the yarn when the cover means moves to the open position so that the yarn is free to drop onto the heating plate for advance along an operative path of travel in contact with the heating plate.
In accordance with the present invention, the cover means is utilized for guiding the yarn when the latter is threaded. To this end, the yarn guides are arranged on the cover means. In a preferred embodiment, when the cover means is closed, the yarn is guided in the temporary yarn path by both stationary yarn guides, which precede or follow the heating plate and are aligned with the latter, and yarn guides which are attached to the cover means. In this temporary yarn path, it is possible to then insert the yarn in the false twist unit and into the feed system downstream of the false twist unit, which are both in operation, and advance and false twist the yarn.
When the cover means is opened, the yarn is released for threading on the heating plate. Subsequently, the feed system upstream of the heating plate is engaged, thereby starting the operation.
The apparatus and method of the present invention allow the yarn to be threaded on a heating plate which faces away from the service aisle and to put the processing station into operation at the same time.
A special advantage of the invention is that it is not necessary to open the cover means so as to bring the yarn in the temporary yarn path, in which the yarn extends at a distance in front of the hot plate. Rather, the cover means is opened only when the yarn is in its temporary path, i.e., advances substantially parallel to the heating plate. As a result, it is necessary to open the heater only for a very short period of time.
In the preferred embodiment, the cover means is divided into separate longitudinal segments, and with the cover segments being separately moveable between the open and closed positions. This structure is particularly suitable for processing sensitive yarns, such as undrawn or partially oriented yarns (POY), which still need to be finish drawn during the false twist texturing operation. More particularly, this structure permits the yarn to be advanced and false twisted while subjecting it to only a slight heating. To this end, one partial length of the cover means can be opened in such a manner that the yarn drops over this partial length onto the heating plate and contacts the plate at that point. Preferably, the partial length is at the beginning of the plate. Only after this "preheating" the yarn is brought to its operating tension, and the drawing is initiated. Then, the yarn is able to withstand also the heating over the entire length of the heating plate, and the other partial lengths of the cover means are then opened.
To bring the yarn to its temporary path parallel to the heating plate, the yarn guides on the side facing away from the heating plate are open. Various possibilities for unloading the yarn from the yarn guides are available. A preferred and important feature of the present invention is that this unloading occurs synchronously with the opening and preferably by the opening of the cover means
In one embodiment, the cover means comprises a pair of laterally adjacent covers, and each cover may be rotated or tilted about an axis parallel to the heating plate, so that the yarn can be dropped, for example, from the yarn guides. To this end, the contact surfaces of the yarn guides are constructed straight or slightly curved. The contact surfaces project beyond the cover edge to such an extent that the dropping yarn falls into the heating plate.
However, in the case of this embodiment, each cover will also have to perform a lateral movement in addition to its rotating or tilting movement, so as to effect an opening. As already indicated, however, it is a preferred object of the present invention to construct each cover and the yarn guides such that the opening movement also represents simultaneously the movement necessary for the dropoff. This objective is achieved in still another embodiment, where the cover means comprises a pair of laterally adjacent covers, with a first guide edge means mounted to one cover and a second guide edge means mounted to the other cover. In the closed position, the two guide edge means define a yarn receiving Vee when viewed in cross section. It is possible to apply this embodiment especially when double heaters are used. In this case, the heating plate contains two parallel grooves, one for each yarn. The two covers are separated along a center plane between these two grooves, and each cover can be opened separately. During the opening by rotating or laterally shifting of one cover, the guide edge means attached thereto serves as a supporting edge, which loses is supporting function, when the cover is opened. The guide edge means located on the other cover is operative as a sliding edge, which remains stationary and along which the yarn slides off. Since the sliding edge terminates substantially above the vertical center plane of the opened heater groove, the yarn drops into this heater groove. In the case of a rotatable cover, the sliding or supporting edges are curved, with the center of curvature preferably being located substantially along the axis of rotation of the cover associated to them.
The above embodiment has the advantage that it is possible for both tiltable and laterally displaceable covers. Laterally displaceable covers have the advantage that they can be adapted to the curvature of the heating plate. In the case of laterally displaceable covers, it is possible to provide for the movement of the yarn onto the heating plate by providing a yarn guide which is carried on each cover, and a fixed yarn contacting member which serves to engage the yarn carried by the yarn guide when the cover is moved to its open position so as to cause the yarn to be released and drop onto the heating plate.
Any of the displaceable embodiments also provides a constant distance between the heating plate and the cover surface facing it over the length of the heating plate, in that the covers may be curved so as to follow the curvature of the heating plate.
To be able to adapt the covers to a considerable curvature of the heating plate, the covers may be divided into separate longitudinal segments. When threading sensitive yarns, for example, of polyester, it will be useful to preheat the yarn somewhat. To this end, the separate opening of the cover segments will be of service, in that the division of the cover into segments ensures that the yarn contacts the heating plate only over a short length, and a damage to the yarn to be threaded by the heat is precluded until its final drawing.
To initially thread the yarn along the yarn guides, it may be helpful to use a piston which is moved over the yarn guides, and to which a yarn carrier is attached, note for example DE-PS 24 55 117. The piston may slide in an air-carrying tube, which possesses an arm to carry along the yarn (note De-PS 2454 668), or an air-carrying, slotted tube, in which the yarn is advanced (note DE-PS 24 29 722 or German Patent Application 39 32 306.4).
BRIEF DESCRIPTION OF THE DRAWINGS
Some of the objects and advantages of the present invention having been stated, others will appear as the description proceeds, when taken in conjunction with the accompanying drawings, in which
FIG. 1 is a cross sectional view of a yarn heating apparatus which embodies the features of the present invention;
FIGS. 2 and 3 are similar cross sectional views of further embodiments of the present invention, and
FIG. 4 is a schematic side elevation view of a yarn false twist crimping apparatus which embodies the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Shown in all embodiments is a yarn heating apparatus which includes a heating plate 2. The heating plate is provided with two yarn grooves 3. It should be noted that the illustrated embodiments are all arranged symmetrically to their longitudinal direction, i.e, to their central plane, which is indicated by the dash-dot lines in FIGS. 1-3. Thus, the mirror plane extends in the center between the two yarn guide grooves 3. The heating plate 2 is of hollow profile, which is filled with a heat-transferring fluid or a heat-transferring vapor and hermetically closed. In the illustrated embodiments, a surface of the heating plate is made wavy, so that two yarn grooves 3 are formed. The heating plate is inserted into a channel 5 of an insulating box 4 with a rectangular cross section. Thus, the insulating box 4 surrounds the heating plate 2 on three sides, and the yarn grooves 3 are directed to the outside of the channel 5. On its outside, the channel 5 is closed by cover means which is generally indicated at 6. The cover means 6 is divided in longitudinal direction along the center plane between the two yarn grooves 3, thus resulting in two separate covers 6.1, 6.2, which can be separately opened.
In the embodiment of FIG. 1, the two covers 6.1 and 6.2 are movable laterally, i.e. in a direction perpendicular to the longitudinal direction of the heating plate 2. To this end, the covers 6.1 and 6.2 extend on the upper side 7 of the insulating box 4. A wedge 8 which is attached to the insulating box 4, and a groove 9 on the underside of the cover, serve for straight-line guidance. For the movement of the covers, a rocking lever 10 is used, which is attached to a pivot rod 13, and which engages with its free end a block 11 sliding in a guideway 12 on the upper side of the cover. The rod 13 can be pivoted with a handle 14.
Mounted on the upper side of each cover 6.1 and 6.2 are several longitudinally spaced apart yarn guides 15. Each yarn guide 15 has a sliding edge inclined toward the mirror plane. The sliding edge terminates in the region of the mirror plane in a slight trough. A plurality of longitudinally spaced apart and fixedly mounted yarn contacting and dropoff guides 16 project into this trough. To this end, each yarn dropoff guide 16 possesses an end, which forms an acute angle with the sliding edge of the yarn guide 15 and it is sufficiently short so that the yarn moving down the sliding edge is able to slide below the end of the yarn dropoff guide 16 and into the trough. The yarn guides 15 and the dropoff yarn guides 16 are staggered relative to each other in the longitudinal direction and spaced apart from each other. The end of the dropoff guides 16 extends below the sliding edge of the yarn guides 15 only a short distance.
Above the sliding edges of the yarn guides 15, threading yarn guides 17 are arranged. A threading yarn guide 17 is shown in FIG. 1 as a tube 18, in which a piston 19 slides. The tube 18 extends over the entire length of the heating plate. The tube 18 has a longitudinal slot 22, and the piston 19 is provided with an arm 20 projecting from the longitudinal slot. The tube can be supplied with compressed air through a connecting pipe 21. A yarn 1 may be attached to the arm 20.
It should be noted that other threading yarn guides 17 may be used, such as, for example, the yarn guide which will be described below with reference to FIG. 2.
To thread a yarn, the piston 19 is moved to the region of the inlet side of the heating plate, and the yarn is attached to the arm 20 by a loop. Then, compressed air is supplied to the tube, so that the piston moves to its other end position. In so doing, the arm 20 carries the yarn 1 along and places it on the inclined sliding edge of the yarn guides 15. As a result of inserting the yarn into the feed systems upstream and downstream of the heater, the yarn 1 is tensioned and slides now along the inclined edge of the yarn guide 15. In so doing, it enters into the wedge-shaped gap, which is formed by the inclined sliding edge of yarn guide 15 and the end of the yarn dropoff guide 16. The yarn is able to move below the end of the dropoff guide 16 and to thus enter into the trough of the yarn guides 15. At this point, the two yarns advance without being in contact with the heating plate 2. By the displacement of the two covers 6.1 and 6.2, it becomes now possible to thread the two yarns 1. To this end, the lever 10 is pivoted. As a result, the two covers perform a movement substantially perpendicular to the mirror plane, whereby the yarns get caught behind the lower ends of the dropoff guides 16, which project in the shape of a hook, and they are pushed over the ends of yarn guide 15 and finally drop down. Since the yarn dropoff guides 16, which are in this process contacted by the yarn, are arranged substantially vertically above the yarn grooves 3, the yarns drop into the gap opening between two covers 6.1 and 6.2 and into the yarn grooves 3. In so doing, the covers can be returned to their closed position. The entire process of opening and threading the yarn takes only a fraction of a second, so that the heat losses are very small.
In the embodiment of FIG. 2, the two covers 6.1 and 6.2 are rotatably supported. To this end, a double hinge lever 23 is used. The double hinge lever 23 is provided with a fixed lever 24, which is attached on an outside wall of the insulating box 4. Connected with the fixed lever 24 is an temporary lever by means of a first joint 25. This temporary lever rests on the upper side 7 of the insulating box 4. The temporary lever is connected by means of a second joint 26 with a cover lever 27 attached to the cover. The two joints 25 and 26 are each located at the corners of the outline of the insulating box 4. On the upper side of the cover facing away from the heating plate 2, a plurality of yarn guides 15 are mounted in the longitudinal direction. These yarn guides have a sliding edge, which terminates in the region of the heating plate in a trough. In its operating position, each cover is locked in position such that the cover with the yarn guides 15 mounted thereon, slopes toward the center plane of the heating plate.
Arranged above the two covers are yarn threading devices 17. In the embodiment of FIG. 2, an air carrying tube 18 is shown, which has a slot 22 extending over its entire length. The tube itself extends over the entire length of the heating plate. It can be moved on a guide rod 30 vertically to the center plane of the heating plate, so that it does not interfere with the pivotal movement of the cover, which will be described below.
The covers 6.1 and 6.2 are in their closed position in FIG. 2. For purposes of threading, the yarn is placed against the tube 18 in the region of the yarn inlet of the heating plate, and advanced by the air current generated in the tube 18 to the opposite end of the tube 18 and the heating plate. In so doing, the yarn drops from the slot 22 onto the yarn guide 15 as a result of the developing yarn tension. The yarn then slides along the edge of the yarn guide 15, which is inclined in the closed position, into the trough. When the two yarns advance in the trough, the cover 6.2 on the right side in FIG. 2 is rotated anticlockwise, whereas the other cover 6.1, which is shown only in part, is rotated clockwise. To enable this rotation, the insulating channel 5 is here shown somewhat deeper than in the embodiment of FIG. 1. Its depth corresponds to about half of the cover width. As a result of this rotation, the yarn guide 15 is also tilted to the unloading position 28 shown in dashed lines. Since the end of the yarn guide 15 is so long that it is located in the tilted position substantially vertically above one of the yarn grooves 3, each yarn is unloaded into its designated groove. Now, the two covers can be closed again, in that they are rotated back to the position shown in solid lines.
Beyond the above, it is also possible to open the covers so completely that the heating plate can be readily cleaned. To this end the yarn threading devices 17 on the guide rod 30 are moved so far that they do not impede the rotation of the cover. Then, each cover can be rotated to the cleaning position indicated in dashed lines at 29.
In the embodiment of FIG. 3, the cover means 6 is likewise divided in the center plane between the two yarn grooves 3.1 and 3.2, thus resulting in two covers 6.1 and 6.2. Each of the covers is rotatably supported in one or several hinges. As a result, it is possible to open each of the covers 6.1 or 6.2 independently of the other cover so as to expose the channel 5 above the yarn groove 3.1 or 3.2. Attached to each of the covers 6.1, 6.2 are pairs of strips 15.1 and 15.2 respectively, i.e., of each pair, one strip 15.1 is mounted on the left cover 6.1 and the other strip 15.2 on the right cover 6.2. The two strips cross each other and form, when viewed in cross section, a Vee, whose apex extends in the center plane between the two yarn grooves 3.1 and 3.2, and which is upwardly open, i.e. on its side facing away from the heating plate.
Otherwise, each of the strips 15.1, 15.2 also extends beyond the apex of the Vee, i.e. into the center plane through the bottom of one of the grooves 3.1, 3.2. Thus, the strip 15.1, which is attached to the left cover 6.1 projects beyond the apex of the Vee to the center plane through the right yarn groove 3.2. The other strip 15.2, which is mounted on the right cover 6.2, extends to the center plane through the left yarn groove 3.1. It should be added that each of the edges slopes from its beginning forming the opening of the Vee to its end in direction toward the heating plate. Furthermore, the strips 15.1, 15.2 are curved, with the center of curvature being located approximately on the axis of rotation of each of the hinges associated to the covers 6.1 and 6.2.
Yarn threading devices 17 are arranged above and in the center between respectively two adjacent heating systems. In the embodiment of FIG. 3, an air-carrying tube 18 is shown, which has a slot 22 over its entire length. The tube extends over the entire length of the heating plate. At its two ends, the tube is provided with an inlet pipe 21 for compressed air. A piston 19 slides in the tube. The piston 19 is displaced in the tube by the compressed air supplied at the one or the other end of the tube. Attached to the piston 19 is an arm 20, which projects through the slot 22 to the outside. The free end of the arm 20 accommodates a double arm 32. Mounted on each end of the double arm 32 is a clamping device 33 for the yarn. Illustrated in FIG. 3 is a clamping plate 34, which is pushed with its bottom resiliently against the end of the double arm 32 by means of a spring 35. The yarn can be pulled under the plate bottom by looping the plate edge. The double arm 32 is sufficiently long so that it projects respectively over the opening of the Vee formed by the strips 15.1 and 15.2.
When the yarn is threaded, both covers 6.1 and 6.2 are closed. Two yarns are placed on two adjacent heaters by means of a yarn threading device, in FIG. 3 the yarn threading device on the right. To this end, the yarn advancing from a supply package is looped with its end about the edge of the plate 34 and thereby held in position in the clamping device 33. Then, the piston 19 is displaced by compressed air supplied into the tube 18 from the inlet end of the heater to the outlet end thereof. As a result the yarn held in the clamping device comes to lie in the V-shaped bottom of the crossing pairs of strips 15.1 and 15.2. Furthermore, the yarn is guided over the subsequent cooling plate, inserted into the false twist unit downstream thereof, and withdrawn by a suction gun. It is now possible to insert the yarn into the feed system upstream of the heater, to advance and twist it. Then, the cover 6.2 shown on the right side in FIG. 3 is opened, while the left cover half remains closed. The movement which is performed by the strip 15.2 can be noted from the end position of the strip 15.1 on cover half 6.1, which is shown in dashed lines. For a better view, it was not shown for the right cover half. When the strip 15.2 is now rotated to the right in corresponding manner by opening the cover 6.2, the V-shaped bottom of the crossing strips 15.1, 15.2 migrates on the strip 15.1 which remains stationary, downward in direction of the heating plate. The strip 15.1 is so shaped that its end facing the heating plate is located substantially in the center plane of yarn groove 3.2. Thus, the yarn slides along the strip 15.2, while the other strip 15.1 remaining stationary, and retains its supporting function. As soon as the strip 15.2 is rotated away so far that it no longer crosses the other strip 15.1, the yarn drops downward in direction of the heating plate into the right yarn groove 3.2. The fact that the heater can be opened in segments, the yarn is first brought in contact with only a partial length of the heating plate. Now, the feed system downstream of the false twist unit can be engaged, thereby starting the drawing and false twisting of the yarn. Subsequently, the remaining heater segments are also opened. It is now possible to thread the yarn in the left yarn groove 3.1 and in the adjacent heating system on the left. Before, the piston 19 is returned by an additional supply of compressed air to its initial position in the region of the yarn inlet of heating system. Further, the cover 6.2 is again closed. This results in the advantage that only one half of the channel 5 needs to be opened in each case. As a result it is possible to keep the heat losses low.
Referring now to FIG. 4, the method of threading a yarn on the processing station of a false twist crimping machine is described. To carry out the method, the heater 2 is provided with a cover divided into three parts. It is possible to open the cover segment 6a by means of the actuating rod 10.1 independently of the other two segments 6b and 6c. To service two segments 6b and 6c an actuating rod 10.2 is used. The segments 6b and 6c are interconnected such that can be opened jointly. To this end, reference is made of DE-PS 38 13 133. The other parts are conventional.
When threading a yarn, all segments of the cover are initially closed. The yarn 1 is withdrawn from the supply package 36, threaded through the guide 37, and connected with the arm 20 by means of clamping device 33 (see, for example, FIG. 3) or in any other manner. In so doing, the piston 19, on which the arm 20 is mounted, is still at the left end of the tube in the region of the first feed system 38. Once the yarn is clamped or attached to the arm 20, the piston is moved to the right-hand position, which is shown in FIG. 4, thereby placing the yarn over the yarn guides 15a, 15b, 15c, which are attached on the outside of the cover sections 6a, 6b, 6c, and subsequently over the cooling plate 39. When the piston 10 arrives at the right end of the tube, the yarn is removed by means of a suction gun 42 and inserted into the false twist unit 40 and into the subsequent feed system 41. The feed system 41 is now engaged, and the false twist unit starts to operate. The false twist unit is here an apparatus as is disclosed in EP-B 22743 corresponding to U.S. Pat. No. 4,339,915. The feed system 38 upstream of the heating system is still open.
Now, the first segment 6a is opened by means of handle 10.1. As a result the yarn drops from the outside of the cover and comes into contact with a portion of the heating plate 2. In so doing, the yarn advances from the yarn guide 37, which is located at the inlet end of the heating plate, to the first yarn guide 15b on the cover section 6b. The length of contact is therefore, however, only very short. Consequently, the yarn which is withdrawn by the feed system 41 from the supply package 36 without engagement of the feed system 38, is slightly heated. However, the yarn has not yet undergone its final drawing, since the feed system 38 is still disengaged. As a result, the suction gun 42 continues to remove the yarn to waste. The first feed system 38 can now be engaged, thereby imparting to the yarn a desired drawing. The two other cover segments 6b and 6c are now also opened by shifting the actuating rod 10.2. As a result, the yarn drops over the entire length of the heating plate 2, as seen in dashed lines at 1a. All cover segments are then closed, and the yarn is threaded on the traversing system 43 and the empty tube 44, which has already been put into rotation by drive roll 45.
In the drawings and specification, there has been set forth a preferred embodiment of the invention, and although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation.
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A yarn false twist crimping apparatus includes a curved heating plate which faces away from the service aisle. A cover is positioned to overlie the upper surface of the heating plate, and the cover is mounted for movement between a closed position covering the heating plate and an open position wherein the heating plate is uncovered. To initially thread-up a yarn, the cover is closed and the yarn is guided to an intermediate position along the outside of the cover. The advance of the yarn is then commenced, and the cover is then momentarily opened so that the yarn drops onto the heating plate.
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FIELD OF THE INVENTION
[0001] The present invention relates to a process for the preparation of nanoscale particles of elastic material. More particularly, the present invention relates to a process for the preparation of nanoscale particles of elastic material such as Styrene Butadiene Rubber. In particular, the present invention relates to a process for the preparation of nanoscale particles of elastic material such as Styrene Butadiene Rubber (SBR) by cavitation techniques. Even more particularly, the present invention relates to a process for the preparation of nanoscale particles of elastic material such as Styrene Butadiene Rubber employing hydrodynamic cavitation techniques.
BACKGROUND OF THE INVENTION AND PRIOR ART
[0002] Nanosuspensions have emerged as a promising strategy for an efficient delivery of hydrophobic drugs because of their versatile features such as very small particle size. Methods such as media milling and high-pressure homogenization have been used commercially for producing nanosuspensions [V. B. Patravale, A. A. Date, R. M. Kulkarni, Journal of Pharmacy and Pharmacology, Vol. 56, No. 7, pages 827 (2004)]. The engineering of nanosuspensions employing emulsions and microemulsions as templates has been addressed in the above literature. The unique features of nanosuspensions have enabled their use in various dosage forms, including specialized delivery systems such as mucoadhesive hydrogels. Rapid strides have been made in the delivery of nanosuspensions by parenteral, peroral, ocular and pulmonary routes. Currently, efforts are being directed to extending their applications in site-specific drug delivery.
[0003] The ability to produce the nanoparticles of desired size with great precision (narrow size distribution and small variation) is the key factor of producing the nanosuspensions. The process of producing nanoparticles can be catagorised by two approaches:
The Top-Down approach—where one starts with the bulk material and machines it, way down to the nano-scale, and The Bottom-Up approach, starting at the molecular level and building up the material through the small cluster level to the nanoparticle and finally the assembly of nanoparticles.
Theory of Cavitation
[0006] Cavitation is the phenomenon of sequential formation, growth and collapse of millions of microscopic vapour bubbles (voids) in the liquid. The collapse or implosion of these cavities creates high localized temperatures roughly of 14000 K and a pressure of about 10000 atm or results into short-lived, localized hot-spot in cold liquid. Thus, cavitation serves as a means of concentrating the diffused fluid energy locally and in very short duration, creating a zone of intense energy dissipation [Suslic K. S., J. J., Gawlenowski, P. F. Schubert and H. H. Wang, J. Phy. Chem. 87, 2299 (1983)].
Acoustic Cavitation
[0007] Cavitation is induced by passing high frequency (16 kHz-100 MHz) sound waves i.e., ultrasound through liquid media. When ultrasound passed through the liquid media, in the rarefaction region local pressure falls below the threshold pressure for the cavitation (usually the vapour pressure of the medium at the operating temperature), millions of the cavities are generated. In the compression region the pressure in the fluid rises and these cavities are collapsed. The collapse conditions are dependent on the intensity and frequency of the ultrasound as well as liquid physical properties, temperature of the liquid and the dissolves gases [J. P. Lorimer and T. J. Mason, Chem. Soc. Rev. 16, 239-274 (1987)].
Hydrodynamic Cavitation
[0008] Hydrodynamic cavitation can simply be generated by the passage of the liquid through a specified geometry of constriction such as orifice plates, ventury etc. When the liquid passes through the constriction, the kinetic energy of the liquid increases at an expense of the pressure. If the throttling is sufficient to cause the pressure around the point of vena contracta to fall below the threshold pressure for the cavitation (usually the vapour pressure of the medium at the operating temperature) millions of the cavities are generated. Subsequently, as the liquid jet expands, the pressure recovers and this results in the collapse of the cavities releasing the energy in the form of a high magnitude pressure pulse. During the passage of the liquid through the constriction, the boundary layer separation occurs and substantial amount of the energy is lost in the form of turbulence and permanent pressure drop [P. R. Gogate and A. B. Pandit, Rev. in Chem. Engg. 17(1), 2001, 1-85].
[0009] Very high intensity of the turbulence, downstream side of the constriction is generated and its intensity depends on the magnitude of the permanent pressure drop, which again depends on the geometry of the constriction and the flow conditions in the liquid. The intensity of the turbulence has a profound effect on the cavitation activity and the intensity as shown by Moholkar and Pandit [V. S. Moholkar and A. B. Pandit, AICHE J. 43 (6) 1997, 1641-1648]. A dimensionless number known as cavitation number (Cv) is used to relate the flow conditions with the cavitation intensity as follows,
[0000]
Cv
=
P
2
-
P
v
1
2
ρ
V
o
2
Eq
(
1
)
[0000] where P 2 is the recovered downstream pressure; P v is the vapour pressure of the liquid and V o is the liquid velocity at the orifice. The cavitation number at which the inception of cavitation occurs is known as the cavitation inception number C vi . Ideally speaking, the cavitation inception should occur at 1.0. But Harrison and Pandit [S. T. L. Harrison and A. B. Pandit, Proceedings of 9 th Int. Biotech. Symp., Washington, USA 1992] have reported that, generally the inception of the cavitation occurs from 1.0-2.5. This has been attributed to the presence of the dissolved gases in the flowing liquid. Yan and Thorpe [Y. Yan and R. B. Thorpe, International Journal of Multiphase Flow, Volume 16, Issue 6, November-December 1990, Pages 1023-1045.] have shown that Cv is a function of the flow geometry and usually increases with an increase in the size of the opening in a constriction such as an orifice in a flow.
[0010] Advantages of hydrodynamic cavitation over acoustic cavitation have been reported as follows [P Senthilkumar, M. Chem. Engg. Thesis, MUICT, Mumbai, 1997]:
It is one of the cheapest and energy efficient methods of generating cavitation. The equipment used for generating cavitation is simple. The scale up of the system is relatively easy.
Theory of Size Reduction:
[0014] To reduce a material's particle size, large particles or lumps must be fractured into smaller particles. To initiate fractures, external forces are applied to the particles. Generally, the extent of particle size reduction caused by an external force depends on the amount of energy supplied to the particle, the rate at which it's supplied, and the manner in which it's supplied. The application of size-reduction forces can be broken into the following four categories [S. Wennerstrum, T. Kendrick, J. Tomaka, and J. Cain, Powder and Bulk Engineering, January 2005, pp 1-5].
Impact milling: Impact milling occurs when a hard object that applies a force across a wide area, hits a particle with a certain momentum to fracture it. The least size obtained by an impact mills is of the order of 50 microns for mechanical impact mills and less than 10 microns for fluid jet mills [S. Wennerstrum, T. Kendrick J. Tomaka, and J. Cain, Powder and Bulk Engineering, January 2005, pp 1-5]. Attrition milling: In attrition milling, non erodable grinding media continuously contact the material to be ground, systematically grinding its edges down. Attrition mills can reduce 1000 micron (20 mesh) particles of friable materials such as chemicals and minerals down to less than 1 micron. One such type is the media mill (also called a ball mill) [S. Wennerstrum, T. Kendrick, J. Tomaka, and J. Cain, Powder and Bulk Engineering, January 2005, pp 1-5]. Knife milling: In knife milling, a sharp blade applies high, head-on localised shear force to a large particle, cutting it to a predetermined size to create smaller particles and minimize fines. Knife mills can reduce 2 inch or larger chunks or slabs of material, including elastic or heat-sensitive materials down to 250 to 1,200 microns [S. Wennerstrum, T. Kendrick, J. Tomaka, and J. Cain, Powder and Bulk Engineering, January 2005, pp 1-5]. Direct pressure milling: Direct pressure milling occurs when a particle is crushed or pinched between two hardened surfaces. Direct-pressure mills typically reduce 1-inch or larger chunks of friable materials down to 800 to 1,000 microns.
[0019] Most mills use a combination of these principles to apply more than one type of force to the particle to be ground. The very important part is to choose the best type of size reduction mode based on the characteristics of the material to be processed and initial and final size requirements.
[0020] The physical properties of the material to be reduced are also important to decide the method and the equipment to be used for reducing it. Nonfriable materials such as polymers, resins, waxes, and rubber can't be shattered or fractured using regular impact or direct-pressure milling. Knife milling often cannot reduce a nonfriable material to a very fine particle size range. Typical methods, for reducing nonfriable materials require turning the nonfriable material into a friable material by freezing it below glass transition temperature. In certain cases, preconditioning or exposing the particles to a cryogen may be necessary. For low temperature milling with cryogens, care of the components of the equipment is very important as they also become brittle and certain lubricating greases lose their viscosity and freeze [9].
Use of Cavitation in Nanotechnology:
[0021] The extreme transient conditions generated in the vicinity and within the collapsing cavitational bubbles have been used for the size reduction of the material to the nano scale. Nanoparticles synthesis techniques include sonochemical processing, cavitation processing, and high-energy ball milling. In sonochemistry, an acoustic cavitation process can generate a transient localized hot zone with extremely high temperature gradient and pressure [K. S. Suslick, T. W. Hyeon, M. W. Fang, Chem Mater. 8 (1996) 2172]. Such sudden changes in temperature and pressure assist the destruction of the sonochemical precursor (e.g., organometallic solution) and the formation of nanoparticles. The technique in principle can be used to produce a large volume of material for industrial applications but no reports are available in the open literature.
[0022] Use of the cavitation for the formation of the Nanoparticles has been reported by Suslick [K. S. Suslick, S. B. Choe, A. A. Cichowlas, M. W. Grinstaff, Nature, 353 (1991) 414]. He sonicated Fe(CO) 5 either as a neat liquid or in a decalin solution and obtained 10-20 nm size amorphous iron particles. Similar experiments have been reported for the synthesis of the Nanoparticles of many other inorganic materials using acoustic cavitation [A. Gedanken, Ultrasonics Sonochemistry 11 (2004), pp 47-55]. To understand the mechanism of the formation of the Nanoparticles during the cavitation phenomenon, Hot-Spot theory has been convincingly used. It explains the adiabatic collapse of a bubble, producing the hot spots. This theory claims that very high temperatures (5000-25,000 K) [A. Gedanken, Ultrasonics Sonochemistry 11 (2004), pp 47-55.] are obtained upon the collapse of the bubble. Since this collapse occurs in few microseconds (final adiabatic phase), very high cooling rates, (in excess of 10 11 K/s), have been obtained. These high cooling rates hinder the organization and crystallization of the products. For this reason, in all the cases dealing with volatile precursors, where gas phase reactions are predominant, amorphous Nanoparticles have been obtained [A. Gedanken, Ultrasonics Sonochemistry 11 (2004), pp 47-55]. While the explanation for the creation of amorphous products is well understood, the reason for the formation of nanostructured products under cavitation is not yet clear. One possible explanation is that the fast kinetics does not permit the growth of the nuclei, and in each collapsing bubble a few nucleation centers are formed whose growth is limited by the short cavity collapse time. If, on the other hand, the precursor is a non-volatile compound, the reaction occurs in a 200 nm ring surrounding the collapsing bubble [K. S. Suslick, D. A. Hammerton, R. E. Cline, J. Am. Chem. Soc. 108 (1986) 5641]. In this case, the sonochemical reaction occurs in the liquid phase and not inside the collapsing cavity. The products are sometimes nanoamorphous particles, and in other cases, nanocrystalline. This depends on the temperature in the fluid ring region where the reaction takes place. The temperature in this liquid ring is lower than that inside the collapsing bubble, but higher than the temperature of the bulk liquid. Suslick [K. S. Suslick, S. B. Choe, A. A. Cichowlas, M. W. Grinstaff, Nature, 353 (1991) 414] has estimated the temperature in the ring region as around 1900° C. In short, in almost all the sonochemical reactions leading to inorganic products, nanomaterials have been obtained. They vary in size, shape, structure, and in their solid phase (amorphous or crystalline), but they were always of nanometer size. [A. Gedanken, Ultrasonics Sonochemistry 11 (2004), pp 47-55]. Cavitation being a nuclei dominated (statistical in nature) phenomenon, such variations are expected.
[0023] In hydrodynamic cavitation, nanoparticles are generated through the creation and release of gas bubbles inside the sol-gel solution [I. E. Sunstrom, IV, W. R. Moser, B. M. Guerts, Chem Mater 8 (1996) 2061]. By rapidly pressurizing in a supercritical drying chamber and exposing it to the cavitational disturbance and high temperature heating, the sol-gel solution is rapidly mixed. The erupting hydrodynamically generated cavitating bubbles are responsible for the nucleation, the growth of the nanoparticles, and also for their quenching to the bulk operating temperature. Particle size can be controlled by adjusting the pressure and the solution retention time in the cavitation chamber. Use of the hydrodynamic cavitation for the same purpose has also reported in some literature. [ NanoBioTech News, Vol 3, Number 6, 9 Feb. 2005].
[0024] However, none of the literature available reports use of cavitation techniques in the reduction of the size of elastic particulate material to nano levels.
OBJECTS OF THE INVENTION
[0025] It is an important object of the present invention to provide an energy efficient and versatile method for the preparation of nanosuspension/nanoemulsion of elastic materials using hydrodynamic cavitation.
[0026] It is a further object of the invention to provide a method for the preparation of naosuspension/nanoemulsion of elastic materials by correlating the cavity dynamics with the properties of material to be ground.
[0027] It is a further object of the invention to provide a method for the preparation of naosuspension/nanoemulsion of elastic material using hydrodynamic cavitation process which reduces the energy requirements by more than 2 orders.
[0028] It is a further object of the invention to quantitatively establish the link between cavity dynamics and wet grinding/emulsification phenomena to provide a method for the preparation of naosuspension/nanoemulsion of elastic material using hydrodynamic cavitation process
[0029] As SBR particles are elastic in nature, conventional methods of size reductions such as impacting, grinding are unable to achieve the final size. Therefore, there is need in the art for an effective and simple process for reducing elastic material to nanoscale.
DESCRIPTION OF THE INVENTION
[0030] In the present invention, attempts have been made to reduce the size of the rubber latex particles (Styrene Butadiene Rubber) present in the form of aqueous suspension with 275 microns particle initial size to the nano scale. Acoustic as well as hydrodynamic cavitation methods have been used to meet the objective. The mechanism of cavitation and theory of size reduction has been taken into consideration to obtain and explain the formation of the aqueous nanosuspension of the SBR. The present invention has successfully and unexpectedly achieved preparation of nanoparticles of the SBR employing cavitation technique. While, both acoustic and hydrodynamic cavitation techniques were been employed, hydrodynamic cavitation was found to be to be more energy efficient than the acoustic cavitation on the basis of various parameters. The maximum production rate equivalent to 2 kg/hr (solid processing) has been achieved employing carefully selected parameters using newly developed Hydrodynamic Cavitation set up (made in house).
[0031] Accordingly, the present invention provides a method for the preparation of nanosuspension/nanoemulsion of elastic materials which comprises passing a cavitation liquid through a hydrodynamic cavitation device having a cavitation plate with one or more orifices, passage of said liquid through said one or more orifices causing the pressure of said liquid to drop so as to generate multitude of cavities, simultaneously, feeding a suspension of particulate material to a hydrodynamic cavitation device and circulating said suspension through said cavities, allowing the pressure of said cavitation liquid to recover resulting in collapsing said cavities, collapsing of said cavities causing size reduction of said particulate material, characterized in that said particulate material is an elastic particulate material having an average particle size of 600 to 1000 microns, wherein said hydrodynamic cavitation device is operated at a pressure of 3 to 20 bars and at a velocity of 10 to 40 m/s.
[0032] In a preferred feature, said one or more orifices have a diameter of 0.6×10 −3 m.
[0033] In another preferred feature, said hydrodynamic cavitation device is operated at a pressure of 11 atm.
[0034] In another preferred feature, the liquid flow rate is maintained at 34.8×10 −3 m 3 /h.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0035] The present invention will be described in greater detail with reference to the following non-limiting examples and the accompanying drawings wherein:
[0036] FIG. 1 : Ultrasonic bath sonification set up;
[0037] FIG. 2 : Ultrasonic horn set up;
[0038] FIG. 3 : Schematic representation of HC 1 set up in accordance with the present invention;
[0039] FIG. 4 : Schematic representation of HC 2 set up in accordance with the present invention;
[0040] FIG. 5 : SDEM image of the rubber latex particles.
EXAMPLE 1
Acoustic Cavitation:
[0041] The specifications of the equipments used are as follows:
Ultrasonic Bath:
[0000]
Make: Supersonics
Frequency: 22 kHz
Rated output power: 120 W
Calorimetric efficiency: 34.69% [16]
Dimensions of bath: 0.15 m×0.15 m×0.14 m
Surface area of ultrasound irradiating face: 2.25×10 −2 m 2
Intensity of irradiation: 1.85×10 3 W/M 2
[0049] The 12% (by weight) suspension of aqueous SBR was sonicated in the ultrasonic bath for 3 hrs. The suspension was kept in a beaker and the beaker was kept in the bath for sonication as shown in FIG. 1 . In the next experiment the suspension was diluted further to 6% and 3.6% by weight of solids and sonicated for further 3 hours.
[0050] The second type of equipment was the direct immersion type ultrasonic horn of two different power ratings.
EXAMPLE 2
Ultrasonic Horn (I):
[0000]
Make: Dakshin
Frequency: 22 kHz
Rated output power: 240 W
Calorimetric efficiency: 6% [16]
Diameter of stainless steel tip of horn: 2.1×10 −2 m
Surface area of ultrasound irradiating face: 3.46×10 −4 m 2
Intensity: 4.16×10 4 W/m 2
[0058] The various concentrations of aqueous SBR suspensions were made and sonicated in beaker using above mentioned ultrasonic horn as shown in FIG. 2 . 12%, 6% and 3.6% SBR suspensions (by weight) were sonicated for 1.5 hrs. For 12% SBR concentration, actual delivered power was 13.8 W with the original suspension volume being 20×10 −6 m 3 equivalent to 2.4×10 −3 kg of solids giving net energy dissipation rate of 6.9×10 2 kW/m 3 as estimated calorimetrically.
EXAMPLE 3
Ultrasonic Horn (II):
[0000]
Make: Ace
Frequency: 22 kHz
Rated output power: 750 W (at 60% amplitude 450 W)
Calorimetric efficiency: 10% [16]
Diameter of stainless steel tip of horn: 1.3×10 −2 m
Surface area of ultrasound irradiating face: 1.32×10 −4 m 2
Intensity: 3.4×10 5 W/m 2
[0066] As can be seen from the above specifications that energy dissipation level of the Ace horn are significantly higher than Dakshin horn with 60% amplitude rating (450 W) (actual delivered power is 45 W with suspension volume being 60×10 −6 m 3 equivalent to 2.16×10 −3 kg of solids giving net energy dissipation rate of 7.5×10 2 kW/m 3 ). The liquid was sonicated for 1 hr. The experimental set up was identical to that shown in FIG. 2 .
EXAMPLE 4
Hydrodynamic Cavitation:
[0067] The equipment used for hydrodynamic cavitation studies was essentially multiple hole orifice plate and other details are as follows:
Details of Hydrodynamic cavitation experimental set up 1 (HC 1 set up) used are: Make: In house Operating capacity: 50×10 −3 m 3 /batch Circulating pump: centrifugal pump coupled with 7.5 hp electric motor Diameter of pipe: 3.5×10 −2 m Diameter of orifice hole: 1×10 −3 m No. of holes on the orifice plate: 33 Operating pressure: 4.2 atm
[0076] The method was carried out with hydrodynamic cavitation setup as shown in FIG. 3 . There is an arrangement to bypass the flow i.e., by pass line 6 to control the inlet pressure (up stream) and the liquid flow rate through the main line 1 which holds the cavitating device. The outlet pressure (down stream) is always kept at atmospheric pressure as the discharge is in an open tank 2 . The arrangement of the holes 4 on the plate 5 is shown in FIG. 3 . The inlet pressure (upstream) was maintained at 4.2 atm to get the liquid flow rate through the orifice plate 5 at 333×10 −6 m 3 /sec. The average fluid (suspension) velocities at the orifice 4 were 12.84 m/sec giving the cavitation number (as defined in Eq. 1) as 1.87. The estimated energy dissipation level in the cavitation zone is 7.10×10 2 kW/m 3 , based on the volume of the cavitation zone, downstream of the orifice plate 5 which is comparable to the one used in both the acoustic cavitation set ups. The method of estimation of the energy dissipation has been discussed in the Appendix (I).
[0077] The aqueous suspension of 6% (3 kg solids in 50×10 −3 m 3 ) by weight of rubber latex suspension was used as a starting liquid. Initial mean particle size of the latex in the suspension was 275 microns. The suspension was recirculated for 3 hrs (equivalent to 32 passes) and sample was taken for the particle size measurement.
Details of Hydrodynamic cavitation experimental set up 2 (HC 2 set up) are: Make: In house Operating capacity: 50×10 −3 m 3 /batch Circulating pump: plunger pump coupled with 1 hp electric motor Diameter of pipe: 3.175×10 −2 m Diameter of orifice hole: 0.6×10 −3 m No. of holes on the orifice plate: 1 Operating pressure: 11 atm
[0086] Alternative hydrodynamic cavitation set up was designed to achieve higher orifice velocities and lower cavitation number to improve the cavitation intensity. The HC 2 setup is as shown in FIG. 4 . The positive displacement (plunger type) pump 1 driven by 1 hp motor (not shown) was used for the circulation of the liquid. The orifice plate 5 used had a single hole 4 of 0.6 mm diameter at the center. The liquid flow rate was maintained at 34.8×10 −3 m 3 /hr using a metering pump giving an orifice velocity of 34 m/sec. The cavitation number (Eq.1) at these operating conditions was estimated to be 0.18. The energy dissipation level was estimated to be 16.6 kW/m 3 (order of magnitude lower than acoustic and HC 1 set up) (estimated by the method in the Appendix (I)). For the HC 2 system already processed 6% aqueous suspension from HC 1 was used as a starting material. It had a mean particle size of 129 nm. The samples were taken out after each circulation.
Size Measurement Techniques:
[0087] Particle size analysis was performed using two different methods. The data of particle size measured using SEM was used to calibrate the Coulter in terms of various properties of rubber particles which can not be measured in the size range of the rubber particles obtained (like refractive index). Coulter was calibrated in terms of the various constants required for the system and then used to measure the particle size distribution of entire samples. First SEM (JEOL-6380LA) was used to measure the size of the particles. The sample collected was diluted to the required extent using ultra pure water. The solution was nebulized and collected on conductive carbon tape. After drying the latex particles obtained on carbon tape, the particles were coated with platinum using sputter coater. The images were then obtained using scanning electron microscope and analyzed for the particle size. Sample image is as shown in FIG. 5 . The same sample was then scanned using Laser diffractometry (LD) using the Coulter LS 230 from Beckmann-Coulter (Krefeld, Germany). The laser when incident on the particle, gets diffracted through the angle based on the size of the particle. The results were compared with the results obtained by SEM. The parameters were set to get the same results in terms of the particle size. One more sample was measured by SEM and Coulter to check the confidence level. Samples collected for various runs were then diluted to the required extent using ultrapure water and were similarly analyzed with LD. The diffractometer yields a volume distribution. It counts the number of particles as well as the size of the particle. Coulter was used to measure the particle size as the number of particles measured in a single scan was higher than in SEM, though SEM gives the real picture which can be analyzed using image analysis technique. Also, time required for measurements is less than SEM and it is more easy to prepare the sample for LD as only dilution is required. The particle size is reported in terms of the mean diameter and the variation from the mean diameter. E.g. Particle size of 100 nm with 10% variation means the 90% of the particles measured are having size of less than 100 nm and 10% particles are larger than 100 nm. Although the typical particle size distribution has not been obtained by this method.
Results
[0088] In the case of ultrasonic bath, there was absolutely no change in the size of rubber latex particles at all the solid concentration levels studied. The initial particle size of 275 microns remained unaffected even after 2 hrs of treatment in the sonication bath. The reason for this can be explained on the basis of energy dissipation levels. The suspension was kept in a beaker and the beaker was kept in the bath. Though the efficiency of the bath was 34.69%, only 3% of that energy was transferred to the suspension in the beaker [N. N. Mahamuni, A. B. Pandit, Ultrasonics Sonochemistry, 13 (2006) 165-174]. Even though an independent experiments with the decomposition of aqueous KI solution in the beaker, confirmed the occurrence of cavitation, the number and intensity of the cavitational events were insignificant to alter (reduce) the particle size in 3 hrs of irradiation.
[0089] In the case of the Dakshin horn (I), for the experiments carried out with 12%, 6% and 3.6% by weight of SBR concentration, the mean particle size observed were 400 nm, 80 nm and 60 nm respectively at the end of 1.5 hrs of processing from an initial particle size of 275 microns. The confirmation of the effect of the solid concentration and the processing time was made using 3.6% by weight of solids in suspension and extending the sonication period to 2 hr. The mean particle size obtained was 60 nm with 12% variation. Thus, it was observed that the concentration of the solids present in the suspension plays an important role while carrying out the size reduction. As the solid concentration decreases, the final (equilibrium) particle size also decreases. Also, increase in the sonication time to 2 hrs could reduce the variation. As for 1.5 hr sonication the variation was too large to measure it and for 2 hr sonication the variation was reduced to 12%.
[0090] For the case of Ace horn (II, higher energy dissipation rate), the mean particle size obtained was 40 nm with 10% variation within 1 hr of irradiation time starting with 275 microns of initial size with 3.6% solids in the suspension. This was the lowest final size of the rubber particles, which could be achieved with acoustic cavitation with a scale of the operation of only 60×10 −6 m 3 /batch (with 3.6% rubber particles initial concentrations).
[0091] In the HC 1 set up, the mean particle size after circulation for 3 hours (72 passes) was 129 nm with less than 2% variation. This was the least size of the rubber particles which could be obtained for the energy dissipation level in the HC 1 setup. The important consideration in the HC 1 experiment was the lowest variation (2%) with an increased scale of operation (50×10 −3 m 3 of suspension). Though, desired size of 40 nm could not be achieved in HC 1 set up, the rate of the production (processing) for HC 1 set up works out to be 1 kg of the solids per hour which is substantially higher as compared to the acoustic cavitation method as well as conventional methods like ball mill or gas phase synthesis [Internet source www.wtec.org/loyola/nano/02 — 04.htm].
[0092] In the HC 2 set up, working with 50×10 −3 m 3 of the suspension volume, the mean particle size obtained after first circulation (one pass through the cavitating volume) was 80 nm with 8-10% variation in the size starting with 129 nm initial mean size and 2% variation. This 80 nm suspension was used for the second circulation and mean particle size was reduced to 70 nm, again with 8-10% variation in the size distribution. Then 70 nm size particle suspension was circulated third time and a mean size of 35 nm with less than 2% variation was obtained. For the fourth circulation, this 35 nm suspension was used as a initial liquid and a mean particle size of 20 nm again with less than 2% variation was obtained. The fourth liquid circulation was carried out to check the minimum size (equilibrium) of the particles obtained in HC 2 set up and at given operating conditions. Fifth circulation (with a starting size of 20 nm) of the solution gave the particle size of 50 nm. The reason behind this increased size can be explained on the basis of the cavitational effect. When the high velocity intraparticle collision takes place, if the collision is at a direct angle, particles collision can occur at very high velocities, which induces effective melting at the point of collision. Suslick have reported similar observation in the case of zinc particles [S. J. Docktycz, K. S. Suslick, Science, 247, 1990, 1067]. The particle size measurement in such case gives higher size value. In the FIG. 5 , this effect can be seen clearly.
[0093] In the present situation, rubber latex of 20 nm size may be the limiting size (equilibrium with a local energy dissipation rate). The sample (having mean particle size of 35 nm, third pass) prepared using HC 2 was again analyzed for the mean particle size two months after the preparation. The samples were stored at room temperature in air tight plastic cans. The size of the particles was observed to be the same as that at the time of preparation. All the results and the various calculated parameters are presented in the Table 1. The detail of the sample calculation giving the numbers in Table 1 is given in the Appendix (I).
Discussion:
[0094] In the hydrodynamic or acoustic cavitation set up, there are two possible reasons for the observed size reduction. One of the possibilities is that, when a cavity collapse takes place, the shock wave generated travels through the liquid media generating local pressure gradient and fluid shear causing attrition of the solid particles and the reduction in the particle size. Other possibility is that when the cavity collapses, asymmetrically on the surface of the solid surface it produces a high velocity liquid jet pointing towards the particle surface which results into an action similar to the liquid jet cutting. It is not known conclusively, which of the mechanism could be the dominating mechanism in the present experimental work though the form and the quantum of energy dissipation can throw some light on this. Analysis of the energy requirement for the observed size reduction in terms work index may throw some light on this aspect as is discussed later.
Cavitation Conditions
[0095] The numerical simulations of the cavity dynamics were carried out previously [S. N. Gastgar, M Chem Engg. Thesis, MUICT, Mumbai, 2004] and the dependence of the operating parameters on the cavity collapse pressures and temperatures on various operating parameters has been studied for acoustic as well as hydrodynamic cavitation. The final cavity collapse pressures and the temperatures in the case of acoustic cavitation are mainly dependent on the intensity and frequency of the irradiation. In the case of hydrodynamic cavitation the cavity collapse pressures and temperatures mainly depend on the orifice velocities and downstream pressure recovery conditions. The simulated collapse pressures and temperatures for all systems used under the operating conditions are in the range of 4000 atm and 1700 K showing transient cavitation (i.e. cavity collapses within single cycle) except for the operating conditions of HC 2 set up. In HC 2 set up the maximum pressures and temperatures for each cavity oscillation (stable cavitation) are only in the range of 12 atm and 500 K. One would expect to get finer suspension size with increasing cavity collapse pressure but the experimental results of the invention unexpectedly show a different behavior, indicating that a stable or oscillating cavity is better for the size reduction in this situation than the collapsing cavity. This has been discussed in detail in the following sections.
Comparison:
[0096] Especially, in the case of the hydrodynamic cavitation as compared to the acoustic cavitation, the particle size variation seems to be lower. This indicates a very high degree of mixing and the uniformity within the cavitation zone. Also, energy distribution in the cavitation zone appears to be more uniform in the case of the hydrodynamic cavitation than the acoustic cavitation. The reason for this observation may be the better spatial distribution of the collapsing or oscillating cavities in the cavitating medium in the former. Hydrodynamic cavitation has already been proved to be very efficient for the generation of the cavities [P. R. Gogate, I. Z. Shirgaonkar, M. Shivakumar, P. Senthilkumar, N. P. Vichare and A. B. Pandit, AIChE Journal, 47 (11), 2001, 2326-38.
[0097] A proper distribution of the orifices on the plate is responsible for improved spatial distribution of the collapsing cavities. Energy dissipated per unit volume of the liquid is of the same order for acoustic cavitation and HC 1 set up (Table 1), yet the difference observed in the particle size variation (from the mean) for acoustic is significantly higher (12% and 10%) than hydrodynamic cavitation (<2%) using multiple hole orifice plates. Similarly, it can be seen that by reducing the number of holes to 1 (HC 2 set up), the variation from the mean increases again to 8 to 10%, possibly due to again the localization of the cavitation effect due to a single hole orifice plate in the HC 2 set up. This variation then can be reduced by subjecting the suspension to multiple passes through this single hole.
Limiting/Equilibrium Particle Size:
[0098] The lowest particle size observed in each of the set ups and the operating conditions, can be explained on the basis of the basis of the dynamic behavior of the cavity as indicated by numerical simulations [S. N. Gastgar, M Chem Engg. Thesis, MUICT, Mumbai, 2004].
[0099] Though the energy dissipated per unit volume for HC 1 set up (7.1×10 2 kW/m 3 ) was one order of magnitude larger than that of HC 2 set up (16.6 kW/m 3 ), the final size obtained in the later was smaller. With higher orifice velocities in the HC 2 set up, the size reduction is possibly taking place more by attrition in the zone downstream of the orifice due to fluid shear, which appears to be more efficient way of producing smaller particles for a solid material such as rubber having some elasticity. As the simulated collapse pressure pulses are also lower in the case of the HC 2 set up, the above explanation is possibly correct. Sample calculations showing this effect are given in Appendix (I) and one can see from these calculations, that rather than the mean (averaged) energy dissipation values, peak (maximum) energy dissipation values decide this limiting reduced particle diameter. This indicates that the average energy dissipation is not the only parameter which decides the final size, but also the distribution and the form of the energy dissipation are equally responsible. Numerical simulation studies [S. N. Gastgar, M Chem Engg. Thesis, MUICT, Mumbai, 2004] indicate that except in HC 2 set up, in all the cases cavities are transient (single oscillations) and in HC 2 set up cavities are in stable mode (multiple oscillations). Transient cavitation gives violent collapse with very high magnitude of temperature and pressure. After collapse of the cavities, shock waves are generated and the size reduction takes place depending upon the strength of the shockwave. In stable cavitation, cavity oscillates many times before collapse and gives low collapse pressures and temperatures compared with transient cavitation. The later, through associated with slow collapse pressures, generate very large fluid shear gradients around the fast oscillating cavities giving rise to mechanical effects like size reduction as the bubble wall velocities are in the range of sound velocities (1500 to 2000 m/s) in the liquid in an alternating directions (towards the centre of the cavity and radially outward), rather than unidirectional velocities in the case of collapsing cavities.
Efficacy of Energy Utilization:
[0100] For the comparison of the performance of the two types of cavitating systems over the selected operating ranges, the energy dissipated per kg of the solids ground for each case has been calculated. The energy taken into consideration is the total energy supplied to the system. Based on the solid content of the suspension, energy dissipated per kg of the solid size reduction has been calculated (J/kg). Sample calculation is again shown in the Appendix (I). The energy dissipated per kg of the solids processed (Table 1) clearly indicates that hydrodynamic cavitation is more energy efficient than acoustic cavitation. For acoustic cavitation set up the energy dissipation per kg of the solids varies from 2.52×10 7 J/kg to 1.38×10 8 J/kg depending on the operating parameters. While for the hydrodynamic cavitation set up these values vary from 2.026×10 4 J/kg to 6.316×10 5 J/kg, showing three orders of magnitude reduction in the latter case. Since, in the acoustic cavitation case, the fluid velocities due to acoustic streaming are significantly lower (2 order of magnitude lower of the order of 0.5 m/s) [Ajaykumar, PhD ( Tech. ) Thesis, MUICT, Mumbai, 2005] than hydrodynamic cavitation set up (velocities of the order of 10 to 30 m/s), it again suggests, that rather than impact grinding (cavity collapse pressure, releasing shock wave), shear grinding or turbulent shear as a result of the stable oscillating cavity appears to be the controlling mechanism of size reduction in this case.
Creation of New Surface:
[0101] Energy required to create new surface area is calculated for each of the experiments and the results are reported in Table 1. For the same system (rubber latex suspension) the energy required to create new surface are observed to be a function of the type of the equipment used, operating parameters and the solids' concentrations. The range of the energy required to create new surface area was found to be in the range of 1.58×10 −1 J/m 2 to 2.073×10 3 J/m 2 , again showing over 4 orders of magnitude of variations depending on the system and operating conditions. This again confirms the role of the type of grinding mechanism in deciding the relation between the energy supply and the increase in the surface energy (area×interfacial tension) of the system.
Work Index Calculations:
[0102] Work Index (WI) is calculated on the basis of the total energy supplied to the system for the reduction in size and increase in the particle surface area. From the knowledge of the Work Index for the various equipments, (for the same material) it is possible to find out the right kind of the equipment with optimized operating parameters for a specific grinding operation. It also suggests the possible mechanism responsible for the observed the size reduction, if one compares the WI values calculated in this work, with the WI values reported in the literature [ Perry's Chemical Engg. Handbook, pp 8-11]. For the present system the range of the work index (WI) is from 20.53 to 9452 as reported in Table 1 (The details of the calculations are given in Appendix (I)). This again confirms that the mode and the intensity of energy dissipation are more important than the total quantum of energy dissipation to obtain particles of a specific size.
Cost Estimation
[0103] The cost of size reduction includes the operating cost (electricity consumption). The amount of electricity required to run the equipment was calculated knowing the rated power of the equipment to reduce the material from an initial size to the final size. The presented data from Table 1 shows that the operating cost per kg of the processed solids of a given initial sizes to the final sizes. Sample calculation is given in the Appendix (I).
[0104] For the size reduction of the rubber latex particles, various equipments under different operating conditions have been used. For each of the equipment used, various parameters responsible for its observed performance have been calculated to study the effect of the operating parameters on the extent of size reduction. From Table 1, it can be seen that, the hydrodynamic cavitation set up appears significantly cost effective in reducing the size of the elastic material like rubber to the nano scale.
Scale Up Issues Related With Acoustic Cavitation:
[0105] Scale-up of such process is of great interest for nanoparticle synthesis. High energy ball milling in terms of high-volume process has been instrumental in generating nanoparticles for the preparation of magnetic, structural, and catalytic materials. However, the process produces polydispersed (large variation) amorphous powder, which requires subsequent partial recrystallization or segregation (which is very difficult) before the powder is consolidated into nanostructured materials. Also, a great care in terms of contamination is required for these kinds of secondary operations. Although gas-phase synthesis is generally used for low production rate processes (typically in the 100 mg per hour range) in research laboratories, higher rates of production (about 20 g per hour) are also being demonstrated [Internet source www.wtec.org/loyola/nano/02 — 04.htm]. Even higher production rates (about 1 kg per hour) are now being achieved commercially with gas phase nanoparticle synthesis processes. [Internet source www.wtec.org/loyola/nano/02 — 04.htm]
[0106] In the present invention, using the acoustic cavitation, it was observed that by adjusting the operating parameters the desired final size of the particles (˜40 nm) with a very low polydispersity (<2%) could be achieved. But the maximum scale of the operation was limited to the processing of 2.4×10 −3 kg/hr of solids. In acoustic cavitation system, the cavitation zone starts from the surface of the horn and extends in the bulk liquid along the axial direction. As the axial distance from the horn tip increases, the cavitational activity and cavitaional intensity in the liquid media decreases [P. M. Kanthale, P. R. Gogate, A. B. Pandit and A. M. Wilhelm, Ultrasonics Sonochemistry, Volume 10, Issue 6, October 2003, Pages 331-335]. So the available active cavitational volume where the actual size reduction is taking place is small. Much of the energy supplied is dissipated in generating liquid circulatory currents lowering the size reduction operation efficiency of the system in terms of the number of the cavitational events and the subsequent size reduction.
[0107] Advantages of the hydrodynamic cavitation over acoustic cavitation have already been discussed. Again to overcome the scale up issues, same advantages can be considered effectively. To increase the cavitational volume in the case of acoustic cavitation set up, it is necessary to use multiple transducer system. Using multiple transducers creates the interference pattern and expected cavitation pattern is not obtained. The cavitational volume (Pressure recovery in the case of pipe flow takes place within 8 times the pipe diameter, so the volume present in that length of the pipe is considered as cavitational volume) in the case of hydrodynamic cavitation is a function of pipe diameter. So depending upon the extent of size reduction required and the quantum of amount to be processed the set up in terms of pipe diameter and orifice opening (orifice diameter, number of holes in orifice and arrangement of holes on the orifice) can be easily modified along with an increased pumping capacity. And adjusting the operating conditions (maintenance of Cv) the required goal of size reduction can be achieved on practically any scale of operation.
Conclusions:
[0000]
1. The hydrodynamic cavitation has proved to be very effective in reducing the size of the elastic material like rubber efficiently. HC 2 is more efficient compared to all the equipments tested in this work. Acoustic cavitation set up can do the size reduction by adjusting the operating parameters such as increasing the power input per unit volume and/or irradiation intensity (W/m 2 ) and decreasing the solid concentrations. The time of the operation varies depending on the final required size and the extent of permissible variation.
2. The mechanism of size reduction appears to be shear and attrition, caused by the cavitation phenomenon. Rather than transient cavitation (single high magnitude pressure probe), stable cavitation (multiple oscillation and high fluid shear) shows higher efficacy for size reduction, as in stable cavitation fluid shear direction changes along with the oscillations of the cavity (towards the center of the cavity during contraction and in outward direction during the expansion of the cavity).
3. The stability of the suspension prepared by HC 2 set up was very good even after 2 months.
4. The systems used in this work can also be used for the size reduction of hard and brittle materials as such but may show a different mechanism of the size reduction and hence different equipment (may be transient cavitation) may show higher energy efficiency.
Appendix (I)
[0112] To calculate the various parameters associated with size reduction, some assumptions were made. Firstly size was assumed to be the mean size and variation was taken as zero (i.e. all particles were of same size and no variation at all). The particles were assumed to be perfectly spherical, the SEM image clearly indicates the sphericity.
Energy Balance Calculations:
For Ultrasonic Systems:
[0000]
Case 1: Dakshin horn 230 W, 20 kHz, 1.5 hrs, (efficiency of the horn=6%), 12% solid concentrations, initial size 275 microns, final equilibrium size 400 nm
[0000]
Net
energy
dissipated
=
230
J
/
sec
×
1.5
hr
×
3600
sec
/
hr
×
0.06
=
7.452
×
10
4
J
Energy
dissipated
per
unit
volume
of
liquid
=
(
230
×
0.06
)
/
20
×
10
-
6
=
6.9
×
10
5
W
/
m
3
Net
energy
dissipated
/
kg
of
solids
=
74520
J
/
2.4
×
10
-
3
kg
=
3.105
×
10
7
J
/
kg
Initial volume of the each particle (considering the spherical particle) (initial size=275
[0000]
Initial
volume
of
the
each
particle
(
considering
the
spherical
particle
)
(
initial
size
=
275
microns
)
=
(
1
/
6
)
×
(
pi
)
×
(
275
×
10
-
6
)
3
=
1.089
×
10
-
11
m
3
Density of the solids=1000 kg/m 3
[0000]
Initial
mass
of
each
particle
=
(
1.089
×
10
-
11
)
m
3
×
1000
kg
/
m
3
=
1.089
×
10
-
8
kg
Initial
number
of
the
particles
=
0.0024
kg
/
1.089
×
10
-
8
kg
/
particle
=
220373
Initial
surface
area
of
each
particle
=
(
pi
)
×
D
1
2
=
2.38
×
10
-
7
m
2
Initial
total
surface
area
=
(
2.38
×
10
-
7
)
m
2
×
220373
=
0.052
m
2
Final volume of each particle (considering the spherical particle) (final size=400 nm)=(1/6)×(pi)×(0.4×10 −6 ) 3
=3.35×10 −20 m 3
[0000]
Final
mass
of
each
particle
=
(
3.35
×
10
-
20
)
m
3
×
1000
kg
/
m
3
=
3.35
×
10
-
17
kg
Final
number
of
the
particles
=
0.0024
Kg
/
3.35
×
10
-
17
kg
/
particle
=
7.16104
×
10
13
Final
surface
area
of
each
particle
=
(
pi
)
×
D
2
2
=
5.027
×
10
-
13
m
2
Final
total
surface
area
=
(
5.027
×
10
-
7
)
m
2
×
7.16104
×
10
13
=
36
m
2
Increase
in
the
surface
area
=
36
-
0.052
=
35.95
m
2
Total Energy utilized for increasing the surface area=74520 J
So, energy utilized to create new surface area=74520 J/35.95 m 2
=2073 J/m 2
Energy required for size reduction in terms of Work index calculations:
[0000]
P
m
=
0.3162
×
Wi
×
(
1
D
pb
-
1
D
pa
)
P
:
Power
required
in
kW
m
:
Solid
flow
rate
in
Tons
/
hr
D
pa
,
D
pb
:
Initial
and
final
particle
size
in
mm
[0000]
Solid
flow
rate
=
1.6
×
10
-
3
kg
/
hr
=
1.6
×
10
-
6
Tons
/
hr
Power
supplied
=
230
W
=
0.230
kW
D pa =275×10 −3 mm D pb =0.4×10 −3 mm
So, Work Index for the rubber latex particles came to be 9452.86. (For the calculation of the work index total electrical power is considered as work index takes care of the efficiency of the equipments used.)
[0000]
Electrical
power
consumed
=
(
230
W
×
1.5
hr
)
=
345
W
hr
=
0.345
kW
hr
Cost
of
the
electricity
=
0.345
kW
hr
×
4.0
Rs
/
kW
hr
=
Rs
1.38
Total
electrical
cost
=
1.38
Rs
/
2.4
×
10
-
3
kg
of
the
solids
processed
=
575
Rs
/
kg
So, the operating cost for getting 400 nm rubber particles from initial size of 275 micron in the form of suspension (6% solids) is 575 Rs/kg of the solids.
[0000]
Reduction
ratio
=
initial
particle
size
/
final
particle
size
=
275
/
0.4
=
687.5
Cost/kg of the solids processes/unit size reduction=575/687.5
=0.836 Rs/kg
For Hydrodynamic Cavitation System:
[0000]
Case 6: HC 1 setup, 4.2 atm pressure drop, 3 hrs
Total Electrical Energy consumed=5.994×10 7 J (for 3 hrs)
[0000]
Energy
associated
with
the
liquid
=
absolute
inlet
pressure
×
flow
rate
=
526890
N
/
m
2
×
(
0.333
×
10
-
3
)
m
3
/
sec
=
175.45
W
Efficiency
=
(
energy
associated
with
the
liquid
energy
supplied
to
the
pump
)
×
100
=
(
175
/
5550
)
×
100
=
3.16
%
[0000] (The pressure recovery takes place within the length of 8 times pipe diameter. The Cavitational volume is considered as the volume of the liquid in pressure recovery zone. i.e. 8 times of the pipe diameter.) [24]
[0000]
Cavitational
volume
=
π
/
4
×
(
dia
of
pipe
)
2
×
(
length
i
.
e
.
8
×
dia
of
pipe
)
=
π
/
4
×
(
34
×
10
-
3
)
2
×
(
8
×
34
×
10
-
3
)
=
2.47
×
10
-
4
m
3
Energy
dissipated
per
unit
volume
of
liquid
=
(
175.45
)
/
2.47
×
10
-
4
=
7.1
×
10
5
W
/
m
3
[0000] All the subsequent parameters are calculated in a manner identical to the previous case.
Energy dissipated/kg of solids processed=6.32×10 5 J/kg Energy utilized to create new surface area=13.58 N/m Work Index for the rubber latex particles came to be 203. Electrical power consumed=5.55 units/hr Cost of the electricity=22.2 Rs/hr Total electrical cost=Rs 66.6. Solid concentration=6% (3 kg solids) So, the operating cost for getting 129 nm rubber particals from initial size of 275 micron in the form of suspension is 22.2 Rs/kg of the solids processed. Reduction ratio=initial particle size/final particle size
=2131.78
Cost/kg of the solids processes/unit size reduction=0.010 Rs/kg Case 6: HC 2 (Plunger pump set up), 11 atm pressure drop, 1 st circulation Total Electrical Energy consumed=2664000 J Energy associated with the liquid=13.137 W Efficiency=1.78% (The Cavitational volume is considered as the volume of the liquid in pressure recovery zone. i.e. 8 times of the pipe diameter.) [24] Cavitational volume=2.01×10 −4 m 3 Energy dissipated per unit volume of liquid=6.54×10 4 W/m 3 Energy of solids processed=20.26 J/gm Energy utilized to create new surface area=0.712 N/m Work index for the rubber latex particles came to be 47.17. The operating cost for getting 70 nm rubber particles from initial size of 129 nm in the form of suspension is 1.42 Rs/kg of the solids. Reduction ratio=initial particle size/final particle size=1.84 Cost/kg of the solids processes/unit size reduction=0.77 Rs
[0000]
TABLE 1
Energy
required
to create
*Energy
*Energy
new
Operating
Variation
dissipated/
dissipated/
surface
Work
Cost/kg
Energy
Re-
Case
Condition and time
Particle size (nm)
in final
volume
kg solids
area
index
solids
dissipated/
duction
No.
of operation
Initial
Final
size
(W/m 3 )
(J/kg)
(N/m)
calculated
(Rs)
particle
ratio
1
Dakshin horn 230 W,
2.75 × 10 5
400
NA #
6.9 × 10 5
3.105 × 10 7
2073
9452
575
3.38 × 10 −1
68.75
20 kHz, 1.5 hrs,
20 ml 12%
suspension,
2
Dakshin horn 230 W,
2.75 × 10 5
80
NA #
6.9 × 10 5
6.210 × 10 7
828
8273
1150
6.76 × 10 −1
3437.5
20 kHz, 1.5 hrs,
20 ml 6%
suspension
3
Dakshin horn 230 W,
2.75 × 10 5
60
NA #
6.9 × 10 5
1.035 × 10 8
1035
11914
1917
1.13
4583.33
20 kHz, 1.5 hrs
20 ml 3.6%
suspension
4
Dakshin horn 230 W,
2.75 × 10 5
60
12%
6.9 × 10 5
1.380 × 10 8
1380
15885
2556
1.50
4583.33
20 kHz, 2 hrs,
20 ml 3.6%
suspension
5
Ace horn, 420 W,
2.75 × 10 5
40
10%
7.5 × 10 5
2.520 × 10 7
168
2362
466
2.74 × 10 −1
6875
20 kHz, 1 hr,
60 ml 6%
suspension
6
HC1 setup, 4.2 atm
2.75 × 10 5
129
<2%
7.10 × 10 5
6.316 × 10 5
13.6
203
22.2
6.88 × 10 −3
2131.8
pressure drop, 3 hrs,
50 lit 6% suspension
7
HC2 set up, 11 atm
129
80
8-10%
1.66 × 10 4
2.026 × 10 4
0.712
47.17
1.42
2.28 × 10 −14
1.61
pressure drop, 1 st
circulation, 34.8 lit
6% suspension
8
HC2 set up, 11 atm
80
70
8-10%
1.66 × 10 4
2.026 × 10 4
1.89
145
1.42
5.44 × 10 −15
1.14
pressure drop, 2 nd
circulation, 34.8 lit
6% suspension
9
HC2 set up, 11 atm
70
35
<2%
1.66 × 10 4
2.026 × 10 4
0.237
22.63
1.42
3.64 × 10 −15
2
pressure drop, 3 rd
circulation, 34.8 lit
6% suspension
10
HC2 set up, 11 atm
35
20
<2%
1.66 × 10 4
2.026 × 10 4
0.158
20.53
1.42
4.55 × 10 −16
1.75
pressure drop, 4 th
circulation, 34.8 lit
6% suspension
Efficiencies of the system are taken into consideration,
NA # - Variation is too large
HC1 set up - Hydrodynamic set up 1
HC2 set up - Hydrodynamic set up 2
[0000]
Ultrasonic
Dakshin
HC2
System
Bath
horn
Ace horn
HC1 Set up
Set up
Efficiency (%)
34.69%
6
10
3.16
1.78
[0153] Efficiency is calculated on the basis of the total electrical energy supplied and net energy delivered to the liquid media. (Appendix I)
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The present invention discloses a method for the manufacture of nanoscale particles of Styrene Butadiene Rubber (SBR). As SBR particles are elastic in nature, conventional methods of size reductions such as impacting, grinding are unable to achieve the final size. The present invention successfully achieves size reduction of the elastic material to nano scale by carefully controlled hydrodynamic cavitation techniques.
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TECHNICAL SECTOR
[0001] The present invention relates to the technical sector of fertilising materials, more specifically enriching agents and fertilisers of use in all fields of agriculture in general, such as cereal and fodder agriculture, large crops, oil crops, protein crops, and including all related fields, such as forestry, forest crops in general, nurseries, production of vegetables and leguminous plants, and all other types of agriculture, including meadows, biomass crops intended for energy generation, plant cover crops for environmental purposes and domestic or leisure uses on turf or planted terrain, hereinafter throughout the description and the claims: “enriching agents”.
[0002] More specifically, the present invention relates, but on a non-restrictive basis, to enriching agents and fertilisers containing minerals, most specifically calcium carbonates of all types and all origins (natural, or industrial such as, for example, PCC or precipitated calcium carbonate), and more specifically enriching agents known as “basic mineral” enriching agents.
[0003] Lastly, the invention relates specifically to the preparation of such enriching agents or fertilisers in the form of granules with great ground “colonisation” power, i.e. great power of coverage of the ground surface.
PRIOR ART
[0004] Granulated traditional basic mineral enriching agents are generally spread on agricultural soils and then incorporated by working the soil. Compared to powder they have substantial advantages for the client: ease of spreading, lower sensitivity to wind, very substantial reduction of the dust released. For the supplier, spreading of sales and deliveries also has a substantial advantage.
[0005] However, the granulation method reduces the agronomic efficacy of these enriching agents. Firstly, due to a lesser coverage of the soil by fine particles (far fewer impact points per square metre), and secondly due to the granulation method (by compacting, for example) and/or additives added in the course of the granulation. The latter improve resistance to impacts in the spreaders, improve ground distribution of the granules through a centrifugal effect, and limit dust releases during handling or spreading, but greatly impair the dispersal of the elementary particles which constitute them, which reduces the efficacy of granulated enriching agents.
[0006] Enriching agent granules are well known in the prior art, but their action on the ground (in addition to other disadvantages relating to manufacture, transport, handling, dust, etc.) is that of a “breakdown under the effect of gravity”, i.e. the granule disintegrates when exposed to moisture, but crumbles into itself, covering only a diameter of 2-3 mm.
[0007] Since calcium carbonate is very insoluble in water it migrates very little in the soil. The soil must therefore be worked to disperse this type of granule satisfactorily, which is a major constraint for the end user, particularly in crop systems where working the soil is necessarily reduced or impossible (natural meadows, vineyards, forests, golf courses, etc.).
[0008] Certain granules contain soluble salts, notably of nitrogen in “nitric” form. They are very soluble and dissolve very quickly, and enrich the soil by capillary diffusion, without there being any requirement to cover a large ground area.
[0009] Conversely, very insoluble enriching agents are also known, which clearly have an effect only at the point of impact, and cover only an area which is of the order of the size of the granule, for example of the order of one mm.
[0010] Although these problems are well known, and have been so for a long time, in a surprising manner, industry and the users concerned have contented themselves with the current products and, to the knowledge of the Applicant, no products exist which seek to remedy these disadvantages in “professional” use.
TECHNICAL PROBLEM
[0011] The present invention must therefore retain the known advantages of the granules, but must also minimise their disadvantages, giving them greater ground coverage capacity, without however being sensitive to moisture before spreading, whilst resisting the impacts of the manufacturing method, loading into sacks or as bulk, transport and final spreading on the soil. Naturally, it is also imperative to reduce dust release as far as possible and, naturally, to preserve the “nutritious” or “soil improvement” properties of the fertiliser or of the basic mineral enriching agent.
[0012] In addition, the invention also seeks to make such enriching agents effective even when working the soil is impossible or difficult, in natural meadows, or in vineyards, for example.
[0013] The granule must also be both sufficiently mechanically resistant to resist its manufacture and transport, as has been seen above, and be nonetheless capable of “melting” on the ground with very great ground coverage, meaning that there is no, or little, need to work the soil (except in certain types of agriculture where, for other reasons, working the soil is in any event necessary).
[0014] in what follows, the single term “enriching agent” will be used to designate basic mineral enriching, agents, notably with a carbonate base, and most specifically PCC (precipitated calcium carbonate) and/or GCC (natural ground calcium carbonate), but those skilled in the art will understand that the chosen solution also applies, making my necessary adjustments, to nitrogenous, phosphate, potassium or other fertilisers, used alone or in a blend with enriching agents, and, more broadly, to fertilising materials. For the sake of simplicity the word “enriching agent” will designate all these options.
[0015] It will be noted that the main aim of the invention is to make the granule more “effective”, meaning that there is no, or little, need to work the soil. The invention does not seek to reduce the doses, but to make the dose applied more effective. The end user will probably continue to use the “habitual” doses, but the invention will enable them not to increase the necessary doses due to efficacy being reduced through lack of dispersal; they will then clearly observe all the improvements relating to liming or soil fertilisation, including improved yield due to better action against the soils natural acidification.
TECHNICAL SOLUTION
[0016] The general means chosen by the invention is that of “dynamic” disintegration of the granules.
[0017] The term “dynamic disintegration” refers to any form of force able to generate micro-granules over a large ground area around the granule deposited on the ground (broad “coverage” of the ground) by bursting, great fragmentation, great “dispersal”, implying an internal force tending to cause the granule to burst or “explode” when it is in contact with the ground, and more specifically the ground water and/or moisture. Hereinafter, for the sake of simplification, “great fragmentation”.
[0018] The adjective “great” in this case means an order of magnitude which is very markedly superior, as will be seen in the examples, to the closest known dispersals.
[0019] It will be seen below that the invention refers to ground coverage which may be as high as 2 to 5 cm in diameter, compared to 0.3 to 0.7 cm of the granules of the prior art.
[0020] The sole comparative reference will in this case naturally be the granules of the prior art, with the understanding that very satisfactory coverage can be obtained, in particular with powders, but with major disadvantages: dust, sensitivity to wind, etc.
[0021] According to invention, a general means property is used, the function of which is to cause dynamic disintegration of the “enriching agent” granule which will, in contact with ground water and/or moisture, cause bursting or dispersal or “explosion” of the elementary particles (i.e. of the particles which comprise each individual granule). By this means, the product/ground/water contact areas are greatly increased, and therefore the size or area or volume of the granule's zone of influence are greatly increased, thus favouring the neutralisation reactions which are expected from the basic mineral enriching agents or the feeding of the plant by the nutrients contained in the granulated fertilisers.
[0022] The invention therefore relates to a notably basic mineral enriching agent containing as a base a mineral carbonate characterised in that it contains at least one “dynamic disintegration” agent, capable of causing in the presence of water and/or moisture, in the granule and/or at its surface, bursting, a great fragmentation, a dispersal, or a great “dispersal”, i.e. implying a force within and/or on the surface of the granule, tending to cause the granule to burst or “explode” when the said granule is in contact with water and/or moisture, and notably with the ground, and more specifically the ground water or moisture.
[0023] The “dynamic disintegration” will be used for all such phenomena, unless otherwise stated.
[0024] The invention notably relates to such a mineral enriching agent, characterised in that the said carbonate is natural or precipitated calcium carbonate.
DESCRIPTION OF THE INVENTION
[0025] In what follows, several types of embodiment of the invention will be described, supporting the said “general means” through the same function of “great fragmentation of the individual granule”, a function implemented by means of an internal force, generated in contact with free water or moisture of the air (this exposure to ambient moisture will be avoided as far as possible, during manufacture, storage and transport, for obvious reasons, but also during spreading, in order that the dynamic disintegration occurs on the ground or as close as possible to it, so as to cause a maximum effect) and/or, in a greatly preferred manner, of the ground, inside and possibly on the surface of the granule, but essentially inside the granule, due to the reaction of at least one of the components of the granule with the water of the ground (or its moisture), in an extremely preferred manner, with the water entering the granule, which can bring its action to bear in a better manner within the structure of the granule.
[0026] The Applicant, in accordance with the “general function” described above, considered “doping” the basic mineral enriching agent, notably a limestone enriching agent, by quicklime (Ca0).
[0027] However, this leads to a very marked failure, since although quicklime can, certainly, swell in contact with ground water, and cause the granule to explode, before this happens, since it is a product which is extremely reactive and hygroscopic, it will also react in contact just with moisture in the air, and swell. The granules will therefore burst, for example during transport or storage, which is the reverse of the determined goal.
[0028] Through this example, it can be seen that the same water which could cause dynamic disintegration also acts against stability of the granule's properties over time.
[0029] This logical solution has already been tried, and clearly rejected, something which has created a prejudice against this type of technology by “swelling”; indeed, it is not possible either to eliminate ambient moisture, or to transport the granules in vacuum-packed bags or in nitrogen, or to use other eminently impossible solutions.
[0030] Industry has therefore abandoned this approach once and for all, and the Applicant's merit is nonetheless to have continued to explore this approach.
[0031] In fact, the Applicant then turned to the approach of very great fragmentation, as defined above, but seeking to use not a reactive base such as lime, but at least one acidic additive. The latter, reacting with the carbonate of the enriching agent, would lead to intense production of bubbles outside and preferably within the granule, thus causing it to burst.
[0032] It might have been supposed that an acidic additive reacting with the basic limestone enriching agent would reduce its efficacy; with low doses (of the order of 0.5-2%, preferably around 1%, by dry weight) which the Applicant developed this effect is quantitatively negligible.
[0033] To maximise the explosion reaction it would have been, logical to use strong acids, but these are dangerous to handle, and, after testing, react too violently, and are also, due to their high reactivity, difficult to incorporate during the manufacturing “process”.
[0034] It might have been thought to use micro-encapsulated strong acids, for example encapsulated by a polymer, etc., but such solutions are clearly incompatible with another imperative of the invention, which is that of economic acceptability. Indeed, the technical solutions found must not lead to an excessively significant increase of the prices of the granules.
[0035] The Applicant considered using phosphoric acid, but phosphorus is already marketed through other channels, and in this case it would be in quantities which would be too small to be exploitable in agriculture. The difficulty of incorporating this type of product in an industrial “process” and its corrosive action led the Applicant not to take this approach, it is therefore one possible solution, but one which is markedly less preferred, since its effects are less predictable, due to the competition described above.
[0036] The Applicant therefore tried other acids, ones which were both “weak”, in order that they not be too reactive, and which did not come into competition with the components of an enriching agent or fertiliser of the type considered here.
[0037] The Applicant tried known acids and acids which were easily obtainable in the market, such as formic and citric acid, but the gaseous release formed proved to be insufficient to cause, in the field, genuine dispersal of the elementary particles of the granule; fragmentations covering an area of approximately 8-10 mm were indeed achieved in the laboratory, and therefore better than dispersal under the sole effect of gravity, but this did not satisfy the ambition of very great fragmentation which the Applicant had determined as their goal.
[0038] Molasses (sugar in suspension derived from beetroot crops), used at a dose of 2-3% by dry weight, are used as an additive during ganulation, and do indeed satisfy the requirements of granulation, but the granule obtained breaks down solely under the effect of gravity, without any dynamic or active character.
[0039] Continuing with another approach, the Applicant tested manufactured granules in the laboratory and in the field, incorporating into them acrylic polymers known as “anionic super-absorbent” acrylic polymers, made from cross-linked copolymers of potassium acrylamide and acrylate of different ganulometries (300 μm to 3 mm), at different doses ranging from 0.1% to 2%. The disintegration tests undertaken gave interesting dynamic disintegration results (see the results of the field tests). However, the cost of this technology, and the intrinsic nature of the polymers used led the Applicant to consider a less expensive and more natural alternative technology, i.e. one not making use of synthetic chemistry.
[0040] Ultimately, after all these tests, the solution adopted by the Applicant is to use, in a completely preferred manner, and with surprising results, a totally different approach, i.e. a moderately swelling product, of the swelling clay type, and notably of the bentonite type (a well known swelling clay, which there is no need to describe). This clay is used as a binder, or as a secondary retention agent in certain systems, known as dual systems, for the manufacture of paper or card sheets, or as a weighting agent in boring sludges and similar substances.
[0041] Its water-swelling properties, which are however well known, have never been used to accomplish “dynamic” fragmentation according to the invention. In a quite surprising manner, the use of bentonite for this specific application revealed bursting potential, i.e. potential for very active cooperation, mostly with the said “dynamic disintegration”, greatly superior to that which its simple swelling might have led one to imagine, in terms of the bursting during laboratory testing, but also and above all in field tests: after considering the surprising results, and without wishing to be bound by a theory, the Applicant suggests that a synergy is formed by the natural swelling force and the physical compression force exerted by the carbonate during factory compaction.
[0042] This “power” of unforeseeable magnitude is surprising and plays a large part in the invention.
[0043] A conventional granulation method was used, i.e. addition and incorporation of molasses, followed by dry blending, of the enriching agent and of the bentonite, high-speed stirring, followed by passing between two compacting rollers to form a continuous plate, a sort of “carpet” approximately 2 to 3 mm thick, which is then broken up to form polygonal granules which will then be eroded and screened before constituting the more or less regular definitive granule with a diameter of approximately 2 to 5 mm.
[0044] The term “more or less regular polygonal granules” is taken to mean a granule the volume of which, considered from any angle, is visible in the form of a regular polygon, i.e. a polygon the sides (or fines) of which are not completely flat, i.e. which may be damaged, broken or chipped, by the manufacturing, and/or packaging, anchor transport, and/or spreading steps.
[0045] A first series of manufacturing tests with bentonite of IMPERSOL™ brand at different doses, from 5 to 1% by mass, was undertaken on batches of 10 kg initially as a pilot manufacturing run. These tests enabled the manufacturing method to be validated (no dust, possibility of compacting, no soiling of the equipment, satisfactory robustness and satisfactory moisture resistance during storage, transport, handling and spreading).
[0046] The 2% dose represented an excellent technical-economic compromise, with satisfactory laboratory dynamic disintegration results. A field test undertaken (cf. end of text), on a silty soil after simulated rain (15 mm spraying) revealed excellent dynamic disintegration and fragmentation properties, since it led to areas of cover of the order of 3.5 cm in diameter.
[0047] Other manufacturing tests with batches of 10 tons, with a true industrial manufacturing run, were then conducted. The granules obtained also had very favourable field burst ranges, generally of the order of 2 to 4 cm or more, for doses ranging from 1.5 to 3% by weight, with a dispersal of results between 2 and 3 cm in diameter for doses close to 2% by weight.
[0048] The IMPERSOL™ data sheet designates this product as a clay belonging to the family of smectites. Its appearance is that of a light powder of 14% maximum water content, with 30% maximum overtail with a 75-micron sieve (dry testing), and of specific weight of 2.3 g/cm 3 .
[0000] Other Clays which Array May be Used
[0049] Other clays may be used, provided they have swelling properties by constitution, and they cause the granule to burst. Indeed, the tests undertaken by the Applicant with other clays do not systematically enable the hoped-for effects to be obtained.
[0000] Other Minerals which May be Used
[0050] Tests have been undertaken with different materials as supports: calcium carbonate of natural origin from different quarries, dolomites and blends of dolomites with calcium carbonate.
[0051] It will be possible to use the said natural or precipitated carbonates (PCC) in blends with one another, and to use other minerals such as natural or precipitated calcium carbonates (PCC) replacing, in whole or in part, the said carbonate(s) by minerals such as dolomites, natural phosphates blended with the enriching agent (to take advantage of the P205 provided for the plants, and not for its acidic effect), ammonia nitrogenous fertilisers or other fertilisers. These materials are very well known to those skilled in the art, and will not therefore be described in detail here.
[0052] Nitric nitrogenous fertilisers and potassium salts are not concerned, since they are naturally very soluble.
[0053] The present invention will be better understood on reading the following examples, given on a non-restrictive basis.
A Examples of Compacting:
[0054] The Applicant has undertaken compacting tests using different components intended to confer the dynamic disintegration properties.
[0055] For these compacting tests the following criteria were adopted to assess the utility and results of each product tested, with products selected according to different criteria:
Properties of the chips. Quality of hot disintegration. Cold testing in water and on moist cotton. Cost of the products.
B Examples and Results of Doses:
[0060] Impersol™ bentonite was tested at 5%, 2%, 1% and 0.5% by weight of the powdered material used as a support.
[0061] For other products the range actually explored was wider with the lower rates: 0.01%. The upper limit was dictated by the correlative reduction of the fertilising elements or neutralising value contents in the granule, and the increase of the cost price.
[0062] Incorporation rates of the order of 10% are possible and were considered, but they are unnecessarily costly given the resulting improvement of the properties.
[0063] The doses were then gradually reduced.
[0064] The lower limit, 0.5%, corresponds to an improvement which is almost no longer perceptible compared to the untreated control, and which therefore constitutes the lower limit (1% being more realistic).
[0065] The above examples define an effective range (including taking account of the additional cost for the end user), and a preferred value is around 2%.
C Bentonite Results
[0066] The granules to which Impersol™ bentonite, as described above, was added were used, at different doses.
[0067] For each dose, and also for a method without additive (control), 16 granules were positioned on an agricultural soil on a grid measuring 5 cm×5 cm. A chip portion derived from the compacting rollers was also placed in the middle of the grid (the chip is then broken to produce the granules). An analysis of this chip portion is interesting although, naturally, granules are used in the field.
[0068] Using a knapsack sprayer of Berthoud™ brand, fitted with nozzles with slits, 15 mm of rain was applied to this device.
[0069] The quantity of simulated rain was controlled by a rain gauge.
[0070] Photographs were taken before and above all after the rain simulation, for each of the tested doses, and the control.
[0071] FIG. 1 (zone 67 ) represents a control granules test, i.e. without bentonite. The granules and the chip portion are intact, or almost intact, even after 15 mm of rain.
[0072] FIG. 2 (zone 70 ) represents granules containing 1% of bentonite. Visible traces of dynamic disintegration according to the invention are seen with, already, satisfactory coverage of the zone.
[0073] FIG. 3 (zone 69 ) represents a 2% dose of bentonite. Disintegration superior to that of FIG. 2 is noted, with a few granules being passed in powder form covering an already large zone. The dynamic integration which occurred with the chip portion can also be observed.
[0074] FIG. 4 (zone 68 ) represents a 5% dose of bentonite. It is noted that only one granule remains (at the bottom left), which seems to have been less affected than the others, however with white traces covering a broad zone around it.
[0075] The comparative plane projections of the documents, photographs and graphics shows very satisfactory consistency.
Procedure for Assessing the Covered Area:
1) Concerning the Ground Colonisation Area Measurements
[0076] Available photographs were printed life-size.
[0077] Visually, using plane projection comparisons, the differences are clear.
[0078] To be more precise and factual, the limits of ground colonisation of each of the 16 granules were framed between two vertical lines, for each method tested:
Control granule not treated be hare rain Control granule not treated after 15 mm of rain Granule treated with 1% of Impersol™ after 15 mm of rain Granule treated with 2% of Impersol™ after 15 mm of rain Granule treated with 5% of Impersol™ after 15 mm of rain
[0084] The space between the two lines was measured.
[0085] The 16 diameters were then summed, giving a reasonably representative value of the ground area colonisation, and one that is reproducible in all cases.
[0086] These values fully confirm the visual impression.
[0087] These values were used as performance indicators.
[0088] Starting with the unidimensional “sum of the diameters of the 16 granules” variable, this value was squared to reach a concept of two-dimensional area, closer to the sought effect (notion of area coverage).
[0089] The values obtained were compared between the different methods.
[0090] It can be seen that the “Control granule not treated before rain” and “Control granule not treated after 15 mm of rain” are identical. All other things being equal, the dynamic disintegration results can therefore be ascribed solely to the influence of the additives used.
Concerning the Graphs Obtained
[0091] Several graphs were plotted on the above bases, according to the rate of incorporation of the Impersol™:
Neutralising value ( FIG. 5 ) Additional costs ( FIG. 6 ) Sum of the diameters of the 16 granules ( FIG. 7 ) Area covered (above value squared) ( FIG. 8 )
[0096] The areas covered are thus multiplied by a factor ranging from 1 to nearly 10, according to the tested methods.
[0097] By placing the curves on top of one another it is clear that for the optimum range it is necessary to achieve a compromise between:
the improvement of area covered, the increased cost, the reduction of the neutralising value.
[0101] These curves will help those skilled in the art to adapt the dosage values and ranges described above to the particular use which they will envisage,
2) Concerning the Choke of the Range of Rate of Incorporation
[0102] In light of the curves we place this compromise around 2%, and preferentially between 1 and 3%, since it is around 2% that the inflection point of the curve of increase of the areas is found (the point above which the cost increases more rapidly, and the neutralising value declines faster than the area covered increases).
[0103] It clearly appears that an incorporation rate of over 5% will not have much effect, since the gradient of the “area” curve then becomes very shallow.
[0104] The appearance of a plateau of the asymptotic type above 5% is noted.
[0105] The appended curves therefore fully justify the dosing and dose range values described above.
[0106] It is, furthermore, surprising to note that a “plateau” appears from approximately 4-6%, notably 5-6%, according to the “sum of the diameters of 16 granules f (% incorporation)” curve.
[0107] This plateau is also found in FIG. 7 , “Changes of the sum of the diameter of the 16 granules”.
[0108] Concerning the redaction of the rate of fines to be recycled during the method of manufacture (since the granules treated with Impersol™ seem, when they leave the compactor, to produce less dust (rate of particles of diameter of less than 1 mm)), this reduction of the rate of dust production is a substantial advantage in the industry in question.
[0109] The lower limit of the range is around 0.5-0.7 (a very average result, but of low cost), and the upper limit is around 5-6% since, above this limit, two deleterious effects are noticed, namely the neutralising value or the fertilising elements content of the enriching agent is reduced when the clay content is increased, and in addition the cost becomes too high for an additional disintegration effect not justifying this additional cost.
[0110] An effective and reasonably inexpensive range, and one which does not cause too much neutralising value or content to be “lost”, will therefore be between 2 and 4%, preferably 2-3%, and an optimum value appears to be around 2%, i.e. 1.8 to 2.3%, if reference is made to the appended figures.
[0111] Those skilled in the art will understand that the lower limit is dictated by the appearance of an identifiable dynamic disintegration effect, whereas the upper limit is, instead, dictated by the fact that the additional dynamic disintegration is not substantial enough to justify the additional cost.
[0112] Those skilled in the art will also understand that these ranges can vary from one clay to another, without however departing greatly from the above values and, consequently, they may adjust the dosage according to the swelling clay used, by a few simple routine tests, and comparison with the examples presented here. Lastly, those skilled in the art will be able to extrapolate the above values to other swelling clays, since the manufacturer gives the swelling percentage on their data sheets: it is therefore easy to make reference to the Impersol™ product, the data sheet of which, Edition 02 of 23 Aug. 2002, gives a swelling of 11 ml/g minimum (CTIF test, recommendation 403).
Detailed Protocol of the Field Disintegration Tests to Characterise the Invention.
Goal:
[0113] The aim of this test is to observe the changes of the granules, whether or not treated, on a re-moisturised agricultural soil, on which will be applied, using a sprayer, the equivalent of 15 mm of rain.
Plan of the Experiment:
[0114] 1 st Step:
Reconstitution from the soil of a neighbouring field of an artificial plot measuring approximately 1 m×1.30 m with satisfactory visibility, to facilitate the photographs without being hindered by the presence of vegetation. Initial artificial re-moisturisation, to return to a state of moisture comparable with that of the original plot, since the sampled soil has become very dry.
[0117] The initial state is air dried, without free water, to the field capacity.
[0118] Separation into 12 boxes measuring approximately 30 cm×30 cm
[0119] Deposit of 16 granules in a chessboard fashion on a grid with 6 cm intervals measuring approximately 24 cm×24 cm for each box, and addition of a fragment of manufacturing chip in the centre.
[0120] The three products judged most effective during the previous tests are tested and photographed with a control and three incorporation doses, which are different for the different products.
[0121] Super-absorbent cross-linked copolymer of potassium acrylamide and acrylate such as, preferably, but on a non-restrictive basis, the product AQUASORB™ KC.
[0122] Moderately swelling clay of the type described above such as, preferably, but on a non-restrictive basis, the product IMPERSOL™.
[0123] Citric acid; As mentioned above, citric acid is a weak acid which may be used in the invention, but in a markedly less preferred way than swelling or moderately swelling clay, or the super-absorbent cross-linked copolymer. This product is used here to better identify the “reasonable” limits of the present invention.
[0124] To make a visual comparison more evident, the untreated controls are on the top line, followed by the high-dose treatments just below (maximum contrast), followed by the medium dose, and lastly the low dose at the bottom.
[0125] Each elementary box is given a number from 63 to 74, firstly from top to bottom, and then from left to right for the following columns.
Sample A: Aquasorb KC
[0126] With control: Control without Aquasorb KC™ (n° 63)
A 0.1%: Contains 0.1% d'Aquasorb KC™ (n° 66)
A 0.15%; Contains 0.15% d'Aquasorb (n° 65)
A 0.2%: Contains 0.2% d'Aquasorb KC™ (n° 64)
Sample B: Impersol™
[0127] B control: Control without Impersol™ (67)
B 1%; Contains 1% of Impersol™ (70)
B 2%: Contains 2% of Impersol™ (69)
B 5%: Contains 5% of Impersol™ (68)
[0128] Sample C: Citric acid in powder form
C control: Control without citric acid (71)
C 0.5%: Contains 0.5% of citric acid (74)
C 1%; Contains 1% of citric acid (73)
C 2%: Contains 2% of citric acid (72)
[0129] Photographs taken for each box, such that their changes may be able to be compared.
[0130] 2 nd Step:
[0131] Photographs taken at the following steps:
[0000] T1 with 0 mm of artificial precipitations
T2 with 5 mm of artificial precipitations
T3 with 15 mm of artificial precipitations
Analysis of Results:
[0132] Differences clearly appear:
[0000] between the control samples and the samples with additives, between the doses for a given additive, between the different additives.
Comparison of three percentages of Aquasorb™ (+control) at 15 mm.
[0134] Very satisfactory disintegration with Aquasorb™, markedly better at 0.2% than at 0.1% and 0.15%.
Comparison of the three percentages of swelling clays (+control) at 15 mm:
Excellent Disintegration.
[0000]
Comparison of three percentages of citric acid (4 control) at 15 mm:
[0137] Effects compared to the control, but much less impressive than the other additives. Citric acid is therefore the least effective of the three products tested.
[0138] The conclusions are those which have previously been given above.
[0139] Those skilled in the art will understand that the enriching agent is technically adapted on a case-by-case basis to form ground covers which may reach 2 to 5 cm in diameter for a granule of standard size, 2 to 5 mm thick, where the said granule takes the form of a more or less regular polygon, and they will be able to make these technical adjustments without difficulty on reading the above description and examples.
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The invention relates to a particularly basic inorganic soil conditioner containing an inorganic carbonate as the base thereof, characterised in that it comprises at least one “dynamic disintegration” agent capable of causing a breakdown, considerable fragmentation, dispersion, and considerable “dispersion” within the granule, i.e. a force inside and/or on the surface of the granule that tends to cause the granule to break down or “explode” when said granule contacts the soil, and specifically contacts the water or moisture of the soil, and in that said carbonate is preferably natural or precipitated calcium carbonate.
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RELATED APPLICATIONS
[0001] The present patent document claims the benefit of priority to German Patent Application No. 13179854.8-1705, filed Aug. 9, 2013, and entitled “MECHANICAL LOCKING HEAD,” the entire contents of each of which are incorporated herein by reference.
BACKGROUND
[0002] The invention relates to a locking head for a crane jib comprising at least two telescope sections.
[0003] In the case of larger cranes and mobile cranes with telescopic jibs, the individual telescope sections of the jib are usually moved relative to one another by means of a telescoping device in order to extend and retract the jib in a telescoping movement. Such cranes with a telescopic jib and a locking head are already known from EP 0 943 580 B1 and EP 1 153 875 B1. On the end at which the piston rod extends out from the cylinder, the telescoping device used for this purpose has a locking head which can be moved by the telescoping device in the longitudinal direction of the jib and essentially fulfils two functions. Firstly, before extending or retracting the respective telescope sections, the lock between the telescope section to be moved and the next outer telescope section has to be released and locked again at another point after the extending or retracting operation. Secondly, the telescope section which has to be moved has to be coupled respectively with the locking head and hence with the telescoping device so that an extending or retracting movement of the telescoping device causes an extending or retracting movement of the respective telescope section. In this respect, it is necessary to ensure that the respective telescope section is coupled with the locking head before the lock with the next outer telescope section is released and that it is not uncoupled from the locking head again until the lock with the next outer telescope section has been established.
[0004] EP 0 754 646 B1 discloses a locking head, whereby in order to increase operating safety, hydraulic circuits are controlled by drivers positioned by the locking bolts to be moved so that the telescope sections cannot be unlocked until the drivers have been positioned on the telescope section to be moved and conversely, the drivers cannot be released from the telescope section to be moved until the lock between two telescope sections has been established again.
[0005] DE 100 04 838 discloses a locking head, whereby the locking head is coupled by means of a first hydraulic cylinder and the lock between the individual telescope sections is operated by means of a second hydraulic cylinder. As a result, different power sources are provided for the coupling device and the locking device.
[0006] DE 198 24 672 discloses a locking head which is provided in the form of a bush and is displaceable on the cylinder housing of a piston-cylinder unit. A piece with two guide grooves which can be displaced relative to the locking head is provided as a means of operating locking bolts, and a guide ring disposed perpendicular to it and which engages in another guide groove is provided as a means of operating a telescope section lock.
BRIEF SUMMARY
[0007] The objective of this invention is to increase the operating safety of a locking head that is as simple as possible in terms of structural design. This objective is achieved on the basis of the subject matter defined in claim 1 and the dependent claims define features offering further advantages to the principle underlying the invention.
[0008] In accordance with this invention, the locking head is configured such that it can be moved by means of a telescoping device within and along the longitudinal axis of a crane jib comprising at least two telescope sections. The locking head comprises a base body, at least one releasing device configured to release a telescope section lock, and at least one coupling device configured to couple a telescope section to the telescoping device. The locking head comprises an operating member which mechanically acts on the releasing device and the coupling device in order to operate the releasing device and the coupling device. The operating member comprises a first link guide for the releasing device and a second link guide for the coupling device, and the links for the first and second link guides extend in a single plane or in parallel planes.
[0009] In other words, both at least one releasing device and at least one coupling device are mechanically operated via the same operating member of the locking head. The term “mechanically” as used below should be understood as meaning that the operating member transmits forces to the releasing device and to the coupling device. For example, it is conceivable for a fixed body contact to exist between the operating member and a releasing device and a coupling device, respectively. Namely, the operating member acts directly on a releasing device and/or a coupling device or transmits forces at least via one or more dimensionally stable elements to a releasing device and/or a coupling device. The operating member of the locking head proposed by the invention also acts on the releasing device and coupling device in both an operating direction and an opposite return direction. Accordingly, the operating member provides a forced guiding action as it were for the releasing device and coupling device. The link guides each comprise at least one link and at least one element guided in the link. As proposed by the invention, all of the links extend in a single plane or at least in planes extending parallel with one another.
[0010] It is conceivable for at least one of the elements guided in the links to co-operate with the operating member or to be fixedly connected to it. However, in the case of a preferred embodiment, all of the links co-operate with the operating member or in other words are integrated in it. The relative movements of the links and the elements guided in them are likewise parallel with one another given the fact that the link planes are parallel.
[0011] The telescoping device may comprise a hydraulic telescoping device for example, in order to move the locking head, specifically on the piston rod of the telescoping cylinder, although any other means suitable for this purpose may be used such as electric, hydraulic or pneumatic drives, in particular linear drives, for example. Electric, hydraulic or pneumatic motors could also be used, such as pneumatic cylinders.
[0012] The base body of the locking head is preferably fixedly coupled with the telescoping device or with a telescoping device, which is in turn coupled with a fixed base such as the base section of the jib.
[0013] The operating member may comprise an integrally formed component. However, it would also be possible for the operating member to be made up of several parts which are fixedly connected to one another and thus form the operating member.
[0014] Based on a preferred embodiment of this invention, the operating member is configured such that it can be moved relative to the base body of the locking head, and a movement in translation is more particularly preferred. However, it would also be conceivable for the operating member to be configured such that it can be moved relative to the base body of the locking head in a rotating movement, in addition to which a combination of a translating and rotating movement, in other words a pivoting movement, would also be conceivable. The movement of the operating member relative to the base body of the locking head causes the releasing device and coupling device to be operated.
[0015] Based on another preferred embodiment, the releasing device and/or the coupling device comprises at least one element which can be guided in its movement relative to the base body, in particular guided in a translating movement, by means of which the operating member acts on the releasing device or coupling device. In other words, the base body has a guide for elements of the releasing device and/or coupling device, and the operating member is able to act indirectly or directly on these elements in order to operate the releasing device and/or coupling device.
[0016] Based on a particularly preferred embodiment, the operating member should be configured such that the individual telescope sections cannot be released from one another via the releasing device until the telescope section lying respectively inwards has already been fixedly coupled with the locking head via the coupling device. On the other hand, the telescope sections cannot be uncoupled from the locking head until they have already been locked to the respective outwardly lying telescope section. This ensures, by way of a single element, namely the operating member, that a telescope section is neither locked to a telescope section lying outward of it nor coupled with the locking head at any time and thus “unsecured”.
[0017] It is also preferable if the element of the releasing device and/or coupling device which is guided in its movement relative to the base body is guided in a direction extending transversely to, in particular perpendicular to, the direction of movement of the operating member.
[0018] The releasing device of the locking head may also comprise an element which is linked in an articulating arrangement about a bearing that is fixed relative to the base body, which couples the movement of the moved and guided element of the releasing device with the movement of the telescope section lock. This articulated element may be a lever in particular, by means of which the movement of the moved and guided element of the releasing device is converted into that of the telescope section lock. With such a lever, it is possible to couple the direction of movement of the moved and guided element of the releasing device and the differing direction of movement of the telescope section lock, for example a guided translating movement of locking bolts. It is also possible, by means of such a lever, to provide a gear ratio between the movement of the moved and guided element of the releasing device and the telescope section lock. It would also be conceivable for a releasing device to comprise a lever mechanism with several elements or levers linked in an articulating arrangement in order to couple the movement of the guided element of the releasing device with that of the telescope section lock.
[0019] Based on another preferred embodiment, the locking head has two releasing respectively coupling devices acting in essentially opposite directions. In other words, two telescope section locks lying essentially opposite one another as viewed in the cross-section of the telescope can be released and locked by means of the releasing device using such a locking head. The telescope sections can also be coupled with the locking head at two oppositely lying points. It is also conceivable for the directions in which the releasing and coupling devices act to extend transversely to, in particular perpendicular to, the operating direction of the operating member. The latter may also extend essentially parallel with one another. Specifically, when the locking head is in the fitted state, the latter may extend essentially horizontally.
[0020] The return movements may be understood as meaning the movements by which the coupling device is moved so that the locking head is moved out of the coupling or out of engagement with a telescope section and the releasing device moves the telescope section lock into a locked position between individual telescope sections.
[0021] A particularly preferred embodiment is one in which both the forced guide/link for the releasing device and the forced guide/link for the coupling device are disposed in an essentially flat portion of the operating member. In other words, both forced guide/links extend essentially in the same plane. It has also been found to be of advantage to maintain an essentially identical extension of these links (the starting and end points of these links are at an essentially identical height along the direction of movement of the operating element).
[0022] In order to ensure that the individual telescope sections are either locked to another telescope section or coupled with the locking head at all times, the operating member of a preferred embodiment of this invention may be configured such that the telescope section lock is not released until the relevant telescope section has been coupled with the locking head and the telescoping device, respectively, and the coupling is not released until the relevant telescope section has been locked to another telescope section. This ensures that every individual telescope section is at all times either locked to the other telescope sections of the telescope or coupled with the telescoping device. Finally, this effectively prevents any undesired independent movement of individual telescope sections.
[0023] Based on another preferred embodiment of this invention, the operating member is moved relative to the base body via a hydraulic cylinder. However, it would also be conceivable to provide any other actuators suitable for this purpose, for example electric, hydraulic, or pneumatic drives, in particular linear drives. It would also be possible to use electric, hydraulic or pneumatic motors, such as pneumatic cylinders. Since the operating member is the only element needed to operate the coupling device and the locking device, the cylinder(s) acting on the operating member is/are therefore the sole power source for the locking and coupling operations.
[0024] Based on another preferred embodiment, a double-acting hydraulic cylinder may be provided, by means of which the operating member and hence the releasing device and coupling device are operated. The double-acting hydraulic cylinder together with the operating member may be configured such that in a middle position, in other words a position of the piston in the hydraulic cylinder approximately centrally between the maximum deflections, the locking head is coupled with the telescope section respectively being moved, whilst this telescope section is additionally locked to the next outwardly lying telescope section, as illustrated in FIG. 5A . The retraction of the hydraulic cylinder from this middle position could cause the telescope section currently being moved to be released from the next outwardly lying telescope section, FIG. 5B , whereas the converse extraction (in other words the opposite movement of the hydraulic cylinder) could cause the telescope section currently being moved to become uncoupled from the locking head ( FIG. 5C ). In order to switch from the state in which the telescope section being moved is locked to the next outwardly lying telescope section to the state in which this telescope section is coupled with the locking head but is no longer locked to another telescope section, a full cylinder stroke and hence also the “doubly secured” state (locking and coupling of the telescope section) is necessary. Consequently the respective telescope section is at no time totally unsecured, which can in turn be assured by the physical design of the operating member.
[0025] Based on another preferred embodiment, the locking head has a return device, which transfers the operating member into a base position. This may be a base position in which the releasing device is not releasing a lock and the coupling device is not coupling a telescope section with the locking head respectively the telescoping device. By preference, however, a base position is one in which the telescope section respectively being moved is “doubly secured” as described above.
[0026] Another aspect of this invention relates to a crane, in particular a mobile crane, having a telescope comprising at least two telescope sections, in particular a telescopic crane jib, and a locking head based on one of the embodiments described above co-operating with the telescope.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] The invention will be described in more detail below with reference to an example of an embodiment. It may incorporate the features disclosed below individually or in combination. Of the drawings:
[0028] FIG. 1 shows a perspective view of a locking head proposed by the invention.
[0029] FIG. 2 shows a plan view of the locking head proposed by the invention.
[0030] FIGS. 3A-3B illustrate the locking head proposed by the invention in a non-operating position (left) and in an operated position (right).
[0031] FIGS. 4A-4C illustrate the locking head proposed by the invention in a position fitted within a telescopic crane jib in a non-operating position (left) and in an operated position (right).
[0032] FIGS. 5A-5C is a schematic diagram of an alternative embodiment of the invention.
[0033] FIG. 6 illustrates a double-acting hydraulic cylinder provided with a return device.
[0034] FIGS. 7A-7C illustrate the alternative embodiment of the locking head proposed by the invention in a non-operating position (left) and in an operated position (right).
[0035] FIG. 8 shows a perspective view of the alternative embodiment.
[0036] FIGS. 9A-9B illustrate the alternative embodiment in a non-operating position (left) and an operated position (right).
[0037] FIG. 10 shows a plan view of the alternative embodiment.
DETAILED DESCRIPTION
[0038] FIG. 1 illustrates an embodiment of the locking head 2 proposed by the invention, which can be moved via of the telescoping device 1 within a telescopic jib (not illustrated). The locking head 2 is disposed on one end of the telescoping device 1 and is fixedly connected to it. The base body 3 forms the central structure of the locking head 2 and essentially accommodates all the other elements of the locking head 2 or provides a bearing for them.
[0039] Provided on both sides of the locking head 2 are guides for bolts 5 d of the coupling devices 5 , and the direction of movement of the bolts 5 d extends perpendicular to the direction of movement of the locking head 2 . By means of these bolts 5 d, the locking head 2 is coupled with a telescope section to be extended or retracted, the locking bolts 5 d engaging in co-operating holders on the telescope section.
[0040] When the locking head 2 is in the fitted position within a crane jib, the locking head 2 also has two releasing devices 4 disposed at the top, each of which comprises two levers 4 b which are able to move about a pivot bearing disposed on the base body 3 . The levers 4 b of the releasing devices 4 connect at their ends remote from the base body 3 by means of contact portions, not illustrated, which are able to engage in co-operating holders of a telescope section lock.
[0041] The locking head 2 further comprises an operating member 6 , which can be moved parallel with the direction of movement of the locking head 2 and relative to the base body 3 . To this end, a hydraulic cylinder 7 is provided, disposed adjacent to the telescoping device 1 and co-operating with the locking head 2 , which moves forwards (downwards on the left in FIG. 1 ) as the operating member 6 is extracted. In order to move the operating member 6 in the opposite direction, tension springs 8 are also provided, which transfer the operating member 6 back into a base position or at least support the cylinder 7 as this happens.
[0042] As may also be seen, the operating member 6 has a forced guide element or a link guide 4 c, 5 c for both the coupling and releasing devices, in which the co-operating elements, or moved and guided elements, 4 a, 5 a of the releasing devices 4 and coupling devices 5 , respectively, engage. What is of particular advantage in this respect is that the elements 4 a and 5 a engage in the link guides 4 c, 5 c of the operating member 6 from different sides, thereby enabling the operating member 6 to be disposed in a space-saving arrangement between the locking mechanism and the coupling mechanism. This means that neither the releasing device nor the coupling device has to move through the other or past it on the operating member 6 . The movement of the operating member 6 along the longitudinal axis of the jib likewise contributes to this space-saving solution, as does the flat, horizontally extending orientation of the operating member 6 .
[0043] As one can easily imagine, as the operating member 6 moves “forwards” (downwards on the left in Figure) relative to the base body 3 , the elements 4 a, 5 a engaging in the links 4 c, 5 c are moved transversely to the direction of movement of the operating member 6 because the other elements of the releasing devices 4 and coupling devices 5 are fixedly guided on the base body 3 of the locking head 2 so that a movement of these elements relative to the base body 3 in the direction of movement of the operating member 6 is not possible.
[0044] FIG. 2 illustrates the link guide 4 c, 5 c of the operating member. As may also be seen, the bolts 5 d of the coupling devices 5 are moved by means of the link guides 5 c radially outwards, in other words out of the base body 3 , as soon as the operating member 6 is moved out of its base position towards the left in FIG. 2 . Accordingly, the locking head 2 is coupled with a telescope section lying around it by means of the coupling devices 5 immediately after the operating member 6 is operated. The elements 5 a are directly coupled with the bolts 5 d so that the bolts 5 d are moved outwards as soon as the elements 5 a are pushed outwards via the link guide 5 c. The reverse operation is effected in the corresponding way. As may also be seen, the guides 4 c and 5 c are “nested one in the other ” with their outermost portions lying at the same end of the operating member 6 (on the right-hand side in FIG. 2 ) as is the case with their portions lying innermost (on the left in FIG. 2 ). The double link guide 4 c, 5 c is therefore of a very compact design because the links are disposed very closely next to one another. This is also the case, regardless of the latter, because the link guides 4 c , 5 c extend horizontally, in other words cause operation of the elements engaging therein along a horizontal direction.
[0045] As the operating member 6 continues to move towards the left, operation of the coupling devices 5 is halted because the distance of the co-operating link guides 5 c no longer changes and instead, the guides 5 c extend parallel with the direction of movement of the operating member 6 . At the end of operating the coupling devices 5 , the releasing devices 4 are operated and are so by means of the elements 4 a moved in a guided arrangement and engaging in the link guides 4 c. Up to this point in time, the releasing devices 4 remain in their base position because the link guide 4 c extends parallel with the direction of movement of the operating member 6 . However, as the course of the link guides 4 c changes, in other words their distance increases, the elements 4 a are moved outwards accordingly, and the movement of the elements 4 a outwards is converted into an essentially oppositely directed movement of the contact portions, not illustrated, by means of the levers 4 b. The contact portions, which were moved by means of the locking head 2 into a position in which they engage with co-operating holders of telescope section locking bolts before the operating member 6 was operated, are therefore moved back towards the vertical mid-plane of the locking head 2 and thus “pull” the telescope section locking bolts out of their holders in the respective outer telescope section.
[0046] Once the locking head 2 has been coupled with the telescope section to be moved in a telescoping action and the corresponding telescope section lock has been released, the telescope section can be extended or retracted with the aid of the telescoping device 1 . Once the desired position of the telescope section has been reached, the reverse operation of the operating member 6 is initiated by means of the hydraulic cylinder 7 and/or by means of the tension springs 8 .
[0047] Since the moved and guided elements 4 a of the releasing devices 4 are moved back towards the horizontal mid-plane of the locking head 2 , the contact portions together with the bolts of the telescope section lock are first of all moved outwards, thereby locking the coupled telescope section which is then still on the locking head 2 . It is not until after the releasing device has been operated and the operating member 6 has been moved farther towards the right that the bolts 5 d of the coupling devices 5 are pulled back into the base body 3 of the locking head 2 again and the telescope section is thus uncoupled from the locking head 2 .
[0048] FIGS. 5A to 5C provide schematic illustrations of an alternative embodiment of the locking head proposed by the invention in different positions. As may be seen from FIG. 5A , the hydraulic cylinder 7 and hence also the operating member 6 are in a middle position, which means that operation is possible in one direction as well as in the other direction. In this middle position, the locking head is coupled with the innermost telescope section by the coupling device 5 , whilst this telescope section is also locked to the next outwardly lying telescope section. The position illustrated in FIG. 5A is not reached until the hydraulic cylinder 7 has been moved from the position of maximum deflection illustrated in FIG. 5B , in which the locking head is not yet coupled with the telescope section and can therefore be moved within the jib, into the middle position. When the hydraulic cylinder 7 is moved beyond this middle position into the other position of maximum deflection, the two telescope sections are released from one another by means of the releasing device 4 , whilst the inwardly lying telescope section is still coupled with the locking head. In this position, the telescope section can finally be moved by means of the telescoping device. The schematically illustrated return device in the form of two springs 8 is constantly trying to urge the hydraulic cylinder 7 and hence also the operating member into the middle position so that the telescope section respectively being moved is secured by both the next outwardly lying telescope section and the locking head.
[0049] FIG. 6 illustrates a double-acting hydraulic cylinder 7 , which is supplied via hydraulic fluid intake lines 7 b and 7 c. The return device in the form of a spring 8 is disposed between two spring plates 8 a and 8 b and always moves the piston rod into a middle position from which the hydraulic cylinder 7 can be retracted (the annular chamber is pressurised with hydraulic fluid via intake line 7 c ) and extracted (the annular chamber is pressurised via intake line 7 b ).
[0050] FIGS. 7A-7C illustrates an alternative embodiment of the locking head proposed by the invention in different operating positions corresponding to the positions of the first embodiment illustrated in FIGS. 4A-4C . The left-hand drawing shows the telescope in an unbolted and locked configuration whereas the middle drawing shows the telescope bolted and locked and the right-hand drawing shows the telescope bolted and unlocked.
[0051] FIG. 8 shows a perspective view of the alternative embodiment of the locking head proposed by the invention. This embodiment essentially corresponds to that illustrated in FIG. 1 but with a double-acting hydraulic cylinder instead of the single-acting hydraulic cylinder shown in FIG. 1 . As illustrated, the double-acting hydraulic cylinder 7 is also provided with the return device 8 , which in this instance is configured as a spring 8 disposed concentrically with the hydraulic cylinder 7 . FIGS. 9A-9B and 10 essentially correspond to FIGS. 3A-3B and 2 and illustrate the alternative embodiment with a double-acting hydraulic cylinder.
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A locking head is configured such that it can be moved within and along the longitudinal axis of a telescope, which comprises at least two telescope sections, by means of a telescoping device, comprising a base body, at least one releasing device which is configured to release a telescope section lock and at least one coupling device which is configured to couple a telescope section with the telescoping device. The locking head comprises an operating member which mechanically acts on the releasing device and the coupling device in order to operate the releasing device and the coupling device. The operating member comprises a first link guide for the releasing device and a second link guide for the coupling device, wherein the links for the first and second link guides extend in a single plane or in parallel planes.
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This application claims Paris Convention priority of DE 10 2006 048 955.1 filed Oct. 17, 2006 the complete disclosure of which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
The invention concerns a MAS (magnetic angle spinning) NMR (nuclear magnetic resonance) apparatus, in particular an HR (high resolution) MAS-NMR apparatus, with automatic sample supply by a supply unit.
An apparatus of this type is disclosed in U.S. Pat. No. 5,200,702.
Nuclear magnetic resonance (NMR) spectroscopy is a powerful method of instrumental analytics. Rotation at the magic angle (magic angle spinning (MAS)), which is approximately 54°, has proven to be a useful method for improving the line sharpness in the obtained NMR spectra, in particular, for semisolid samples (semisolids), e.g. tissue samples. HR pulse programs are therefore also suited to measure high-resolution NMR spectra of inhomogeneous samples.
For a MAS measurement, the sample material is loosely disposed in a so-called rotor and soaked with an NMR solution, e.g. D 2 O. The rotor is substantially a hollow cylinder that is open on one side. A cap tightly closes the rotor. The cap is substantially rotationally symmetric about an axis. The rotor, which is filled with sample material and closed by a cap, is called sample unit herein. The cap has teeth or blades that can move a sample unit, which is located at a measuring position in an NMR spectrometer, into fast rotation using a gas flow. Rotors and caps are disclosed e.g. in U.S. Pat. No. 5,236,239.
Filling sample material into the rotor, soaking the sample material with NMR solution and closing the rotor with the cap is conventionally effected manually. When the rotor is closed, air and excess NMR solution can escape from the interior of the rotor via a central bore in the cap. The bore in the cap is closed by a screw, which is screwed in manually using a screwdriver when the cap is disposed on the rotor. Manual preparation of the sample units is time-consuming and expensive.
U.S. Pat. No. 5,200,702 discloses automatic supply of the readily prepared sample units to a measuring position of an NMR apparatus and measuring thereof. The sample units are thereby disposed in a stacking tube.
It is the underlying purpose of the present invention to present a MAS-NMR apparatus for preparing sample units, in particular, closing the rotors by caps, in a simple and automated fashion.
SUMMARY OF THE INVENTION
This object is achieved by an HR-MAS-NMR apparatus of the above-mentioned type, which is characterized in that an automatic preparation station for samples is provided, comprising:
a) a rotor storage with several rotors for receiving sample material soaked with NMR solution, b) a cap storage with several caps, wherein each cap is suited to close a rotor and wherein each cap has a central axial bore, c) several movable pins, each being insertable into the central axial bore of a cap to close the bore in the inserted state, d) a cap handling unit which
can grip a cap from the cap storage, move it, and dispose it onto a rotor, a plunger for inserting a pin into the bore of the cap, and a suctioning device for suctioning excess NMR solution that escapes from the bore.
The inventive NMR apparatus effectively automates closing a rotor with a cap.
The inventive NMR apparatus has a cap storage (e.g. a stack of caps or a rack for a plurality of individual caps) and a rotor storage (e.g. a rotor stack or a rack for a plurality of individual rotors). A cap handling unit can move a cap from the cap storage to a rotor, which is filled with sample material and NMR solution, and dispose it thereon. The rotor may thereby be disposed at a special preparation position (e.g. in a holder or intermediate storage) or at its storage location in the rotor storage. The cap handling unit may thereby be grasped and moved e.g. using a robot arm.
A pin is then pressed into the bore of the cap using the plunger of the cap handling unit to close the cap. The pin expands e.g. the cap in a partial area disposed in the rotor. The elastic cap material clamps the pin and seals it with respect to the rotor. The pin may be removed from a pin storage, or one pin may be pre-assembled on each cap of the cap storage. The closing action by the pin, which is substantially cylindrical (and has, in particular, no outer thread), is particularly easy to automate. The plunger can easily be integrated in the cap-handling unit, such that closure can be effected very quickly, directly after disposing the cap. For this reason, automation is particularly fast.
A suctioning device is also integrated in the cap-handling unit, which can remove the NMR solution, which is displaced from the rotor interior during insertion of the pin. This prevents soiling of the outer area of the sample unit, which could disturb sample supply or falsify NMR measurements.
After the sample unit has been automatically closed, it can be automatically moved, together with the supply unit, to a measuring position.
The inventive NMR apparatus typically comprises an electronic control, which takes over the entire sample preparation, sample supply and generally the administration of the samples.
In one particularly preferred embodiment of an inventive MAS-NMR apparatus, the caps have an overflow channel in the area facing away from the sample, where the suctioning device can act. The overflow channel facilitates escape of the NMR solution from the rotor during closing. In the simplest case, the overflow channel extends parallel to and in contact with the bore for the pin.
In an advantageous further development of this embodiment, the caps each have several overflow channels, which are disposed symmetrically about the axis of rotation of the cap, thereby eliminating any imbalance during rotation of the sample unit during the MAS-NMR measurement.
In another particularly preferred embodiment, the preparation station comprises
a sample receiver with several sample containers which receive samples, and a punching device for punching out sample material from a sample container and transferring it into the interior of a rotor. This embodiment also automates insertion of sample material into the rotor. The punching device retains the sample material after punching out and is moved (e.g. via a robot arm) to the rotor, and then releases the sample material.
In another particularly preferred embodiment, the preparation station comprises a capillary for supplying NMR solution into the interior of a rotor, which permits automation of the supply of NMR solution into the rotor. A robot arm may move the capillary. The NMR solution may be supplied into the rotor before or after insertion of the sample material.
In an advantageous further development of the two above-mentioned embodiments, the capillary is integrated in the punching device, which accelerates automatic sample preparation.
In another preferred embodiment, the supply unit can pneumatically move the rotors, which are filled with soaked sample material and closed by caps, to a measuring position of the apparatus. Pneumatic transport is fast and reliable. The starting position of the sample unit in the preparation station may thereby be the location of sample preparation, a particular holder (intermediate storage), or the storage location in the rotor storage.
In another preferred embodiment, the supply unit is designed to pneumatically move the rotors, which are filled with soaked sample material and closed with caps, to a storage position of the apparatus after termination of the NMR measurement. Pneumatic transport is again quick and reliable. The storage position may be the same as the starting position of the sample unit in the preparation station (this is advisable when the starting position is the storage position in the rotor storage) or the storage position is formed in a particular holder (end storage), preferably in the preparation station.
Further advantages of the invention can be extracted from the description and the drawing. The features mentioned above and below may be used in accordance with the invention either individually or collectively in arbitrary combination. The embodiments shown and described are not to be understood as exhaustive enumeration but have exemplary character for describing the invention.
The invention is shown in the drawing and is explained in more detail by means of embodiments.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 a shows a schematic cross-sectional view of a rotor for use with the invention;
FIG. 1 b shows a schematic view from below of the rotor of FIG. 1 a;
FIG. 2 a shows a schematic cross-sectional view of a cap in accordance with the invention, with two symmetric overflow channels and pre-assembled extended pin;
FIG. 2 b shows a schematic top view of the cap of FIG. 2 a;
FIG. 3 a shows a schematic cross-sectional view of a cap in accordance with the invention, with an overflow channel parallel to the bore and with pre-assembled extended pin;
FIG. 3 b shows a schematic top view of the cap of FIG. 3 a;
FIG. 3 c shows the cap of FIG. 3 a with inserted pin;
FIG. 3 d shows a schematic cross-sectional view of a sample unit in accordance with the invention, comprising the rotor of FIG. 1 a and the cap of FIG. 3 a , in the unclosed state;
FIG. 3 e shows the sample unit of FIG. 3 d in the closed state;
FIG. 4 shows a schematic structure of an inventive HR-MAS-NMR apparatus with preparation station, supply unit and NMR spectrometer;
FIG. 5 a shows a cross-sectional view of the sample storage for sample containers and a punching device in accordance with the invention;
FIG. 5 b shows the punching device of FIG. 5 a with punched-out sample material;
FIG. 5 c shows the punching device of FIG. 5 b during filling the sample material into a rotor;
FIG. 5 d shows the punching device and the rotor of FIG. 5 c after filling the sample material into the rotor;
FIG. 5 e shows the rotor of FIG. 5 d during filling-in NMR solution using a capillary;
FIG. 6 a shows a schematic cross-sectional view of a cap in a cap storage and a cap-handling unit in accordance with the invention;
FIG. 6 b shows the cap-handling unit of FIG. 6 a with grasped cap;
FIG. 6 c shows the cap handling unit and the cap of FIG. 6 b after disposing the cap onto a rotor;
FIG. 6 d shows the cap handling unit, the cap, and the rotor of FIG. 6 c after inserting the pin;
FIG. 7 a shows a schematic cross-sectional view of the prepared, closed sample unit in a rotor storage and the front part of a supply unit in accordance with the invention before the sample unit is gripped;
FIG. 7 b shows the sample unit and the front part of the supply unit in accordance with FIG. 7 a during suctioning of the sample unit;
FIG. 7 c shows the sample unit and the front part of the supply unit in accordance with FIG. 7 b , during pneumatic transport of the sample unit;
FIG. 8 shows a schematic cross-sectional view of a pneumatic supply unit in the area of a switch with prepared sample unit in accordance with the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention fully automates the measuring procedure in a MAS-NMR apparatus, including sample preparation, sample transport and storage of rotors.
In accordance with prior art, the sample containers (rotors), which are used in a MAS measurement, are manually filled with sample material and the rotors are also manually filled with NMR solution (lock solvent). Closing of the rotors with a cap and feeding a sample magazine provided on the NMR spectrometer are also effected manually. This is due to the small rotor dimensions and the precision-mechanical closing mechanisms of the rotor caps.
The invention proposes to provide the NMR apparatus with a suitable automatic preparation station, the use of which would omit manual steps. Special inventive rotors, caps, and a cap-handling unit, which are particularly suited for automation, are used at the preparation station.
FIG. 1 a shows a cross-section of a rotor 1 which can be used in the invention. The rotor 1 is designed as a hollow cylinder, which is open on one side. The rotor 1 receives sample material that has been soaked with NMR solution. It can be rotated approximately without imbalance about a central axis, which extends perpendicularly in FIG. 1 a . A two-dimensional matrix code 2 can be provided at the bottom of the rotor 1 ( FIG. 1 b ) for identification. In the example shown, the rotor 1 has a round outer cross-section, but also non-spherical, e.g. polygonal, outer cross-sections are feasible. The rotor 1 moreover has a circular inner cross-section. The rotor 1 may e.g. be produced from glass.
FIG. 2 a shows a cross-section of a first embodiment of a cap 3 for use with the invention. The cap 3 has a continuous central axial bore 4 in which a pin 5 is displaceably disposed. The pin 5 projects past the cap 3 at the upper end facing away from the sample. In this state, the cap 3 is not closed since the bore 4 is connected, below the pin 5 , to the upper side 11 of the cap 3 facing away from the sample via two overflow channels 6 a , 6 b . The two overflow channels 6 a , 6 b are disposed mirror-symmetrically relative to the bore 4 . The lower part of the cap 3 , which faces the sample material in the assembled state, is spherically curved in the embodiment shown. The bore 4 has an opening 9 in the curved lower part. The lower part of the cap 3 has a circular outer cross-section, wherein the diameter is slightly smaller than the inner diameter of the associated rotor (see also FIG. 3 d ).
The top view of FIG. 2 b of the cap 3 also shows the upper openings 7 a , 7 b of the overflow channels 6 a , 6 b . The upper part of the cap 3 has teeth or blades 8 on which a gas flow can act in order to rotate a closed sample unit during measurement (typically with 2,000-15,000 revolutions per second). The cap 3 can also rotate about its center axis substantially without imbalance due to its high symmetry (in FIG. 2 a extending perpendicularly in the center of the bore 4 ).
FIG. 3 a shows a cross-sectional view of another embodiment of a cap 3 . In this embodiment, an overflow channel 6 extends slightly eccentrically (laterally) to the central axial bore 4 . The slight imbalance close to the axis has no negative effect in practice. In the illustrated unclosed state of the pin 5 , the opening 9 facing the sample and the upper side 11 of the cap 3 facing away from the sample are connected via the lower part of the bore 4 and the overflow channel 6 . The top view of FIG. 3 b also shows the opening 7 of the overflow channel. The overflow channel 6 narrows on the border to the bore 4 or pin 5 , such that the pin 5 is safely guided in the bore 4 and cannot slip into the overflow channel 6 .
FIG. 3 c shows the cap 3 of FIG. 3 a in the closed state, i.e. with inserted pin 5 . The pin 5 thereby projects more deeply into the bore 4 than the overflow channel 6 projects into the cap 3 . The pin 5 therefore blocks the connection between opening 9 of the bore and the opening 7 of the overflow channel. In a central section 10 of the cap 3 , the bore 4 is slightly narrower than the diameter of the pin 5 such that the cap 3 is elastically expanded. Suitable cap materials are e.g. Teflon® or Kel-F® which have sufficient elastic deformation properties.
FIG. 3 d shows a sample unit 30 comprising a rotor 1 with disposed cap 3 in the unclosed state. The lower part of the cap 3 and the inner bottom of the rotor 1 delimit a measuring space 31 in the sample unit 30 , which has an approximately spherical shape (a shaped body may alternatively be provided on a straight inner bottom of the rotor 1 , which is spherically curved). The spherical shape prevents magnetic field distortions during an NMR measurement. The measuring space 31 is provided for receiving sample material and NMR solution (not shown for reasons of simplicity). The sample unit 30 of FIG. 3 e is closed, i.e. the pin 5 is inserted. The expanded cap 3 tightly abuts the inner wall of the rotor 1 in an annular area 32 . The closure is designed such that the fast rotation that acts on the rotor 1 during the measurement does not cause any leakage.
FIG. 4 shows an inventive NMR apparatus comprising an NMR spectrometer 41 with a high-resolution magic-angle spinning probe head 42 which has a measuring position 43 for a sample unit and moreover a preparation station 44 and a supply unit 45 for transferring sample units from the preparation station 44 to the measuring position 43 (and typically also back).
The preparation station 44 has a preparation robot 46 which can be displaced in three orthogonal directions x, y, and z (z perpendicular to the plane of the drawing), and, in this embodiment, can handle four different tools 46 a to 46 d using a holder (not shown). The tools are
the front end 46 d (suction pipe opening) of a transfer tube 45 a of the pneumatic supply unit 45 (see also FIG. 7 a ), a cap handling unit 46 b (see also FIG. 5 a ), a capillary 46 c or needle for NMR solvents, which is connected to an NMR solvent supply 47 , and a punching device 46 d (see also FIG. 6 a ).
The preparation station 44 moreover comprises a cap storage 48 , which is designed in the present case as a rack for a plurality of individually disposed identical caps 3 . Each cap 3 has a pre-assembled pin in the unclosed state. A rotor storage 49 is also part of the preparation station 44 . The rotor storage 49 is also designed as a rack for a plurality of individually disposed, identical open rotors 1 . The rotor storage 49 of the shown embodiment serves to prepare samples (filling and closing the rotors) and also to store readily prepared sample units before and after NMR measurements. Moreover, two sample receivers 401 are provided in which a plurality of sample containers 402 are disposed next to each other. Each sample container 402 contains a tissue sample, some sample material of which is to be measured using NMR. The preparation station 44 also comprises a read station 403 for bar codes, matrix codes, RFID or the like to uniquely identify rotors 1 or sample units.
All positions of caps 3 in the cap storage 48 , rotors 1 in the rotor storage 49 , sample containers 402 in the sample receivers 401 and the read station 403 are in the working region of the preparation robot 46 .
A washing station (not shown) may additionally be provided in the working area of the preparation station to clean the tools and to avoid mutual soiling of samples. Intermediate storages or end storages for sample units or rotors may furthermore be provided in the preparation station of other embodiments (not shown), as well as a gripping tool for sample units or rotors for transfer within the preparation station. A tool may be omitted by integrating several functions in one tool (e.g. punching device and capillary).
The preparation proceedings at the preparation station 44 are described below:
In a first work step, illustrated by FIGS. 5 a to 5 d , a piece of sample material is removed from the sample support by the punching device 46 d , and inserted into a rotor 1 .
Towards this end, the punching device 46 d is initially moved in the xy plane over a sample container 402 of the sample receiver 401 using a retracted mechanical slider 51 ( FIG. 5 a ). The punching device 46 d is then lowered in the z direction and an annular cutting edge 56 penetrates into a tissue sample 52 which is disposed in the sample container 402 and separates a piece of sample material 53 (suitable samples 52 are i.a. human, animal and vegetal tissue, in particular, skin, organs, fruit flesh or leaves, but also complete living beings, such as worms). The punching device 46 d is withdrawn upwardly, wherein the sample material 53 remains in the punch opening 54 ( FIG. 5 b ). The punching device 46 d is subsequently moved via a rotor 1 and the mechanical slider 51 is moved downwards, such that the sample material 53 is ejected ( FIG. 5 c ). The shape of the punched-out piece of sample material 53 exactly fits into the rotor 1 . The punching device 46 d is then withdrawn ( FIG. 5 d ). Alternatively, the sample piece may also be pneumatically ejected (instead of the mechanical slider (not shown)).
In a subsequent second work step, the interior of the rotor 1 is filled with NMR solution (lock solvent) 55 (e.g. D 2 O) by means of the capillary 46 c (see FIG. 5 e ). In accordance with the invention, the rotor 1 may alternatively be filled first with NMR solution (receiver of the NMR solution), and the sample material is subsequently filled into the rotor (not shown).
In a third work step, illustrated in FIGS. 6 a to 6 d , a cap 3 is disposed onto the rotor 1 and closed.
The cap handling unit 46 b is moved over a cap 3 located in the cap storage 48 . The cap 3 has a pre-assembled closure pin 5 , which projects past the cap 3 (unclosed state). With the punch 61 withdrawn, the cap handling unit 46 b is lowered onto the cap 3 in the z direction ( FIG. 6 a ). After gripping the cap 3 with clamps (not shown), with the pin 5 remaining in the open state, the cap handling unit 46 b is withdrawn ( FIG. 6 b ) and moved over a rotor 1 which already contains sample material 53 and NMR solution 55 . The cap handling unit 46 b is subsequently lowered, wherein the cap 3 is inserted into the rotor 1 ( FIG. 6 c ). The sample material 53 is thereby typically somewhat compressed and NMR solvent 55 escapes through the bore 4 and the overflow channel 6 on the upper side of the cap 3 . The pin 5 is then ( FIG. 6 d ) pressed into the cap 3 towards the sample (or the sample material 53 ) using the plunger 61 , wherein more NMR solvent 55 escapes via the overflow channel 6 (without the overflow channel it would hardly be possible to press-in the pin, due to the incompressibility of the NMR solution). The escaping NMR solvent 55 is suctioned via a suctioning device 62 , which is integrated in the plunger 61 in the embodiment shown. The suctioning draught can be provided via the recesses on the closing cap 3 or through a small lateral bore 63 in the cap handling unit 46 b . The cap handling unit 46 b can subsequently be retracted (not shown).
In the fourth step, the sample unit 30 , i.e. the readily prepared rotor 1 which is closed by a cap 3 is subsequently pneumatically transferred to the measuring position in the NMR spectrometer (see FIGS. 7 a - 7 c and 8 ). Towards this end, the front-end 46 a of the transfer hose 45 a is moved over the sample unit 30 ( FIG. 7 a ), lowered ( FIG. 7 b ) and the sample unit 30 is suctioned ( FIG. 7 c ). The sample unit 30 is subsequently moved in the transfer hose 45 a . A switch 81 is moreover provided in the supply unit 45 , ( FIG. 8 ) in which the sample unit 30 can be held, such that the direction of motion or the transfer hose can be changed with a flap 82 , i.e. from the transfer hose 45 a which leads to the preparation station, to the transfer hose 45 b which leads to the measuring position in the NMR probe head. During turning, the position of the sample unit 30 relative to the suctioning direction 83 also changes. The switch 81 is typically disposed over the magnet of the NMR spectrometer.
It is also possible to use a rotatable plate with holding positions for several sample units (not shown) instead of a switch with flap.
After the measurement, the supply unit 45 steps are reversed. The sample unit 30 is returned from the measuring position to the switch 81 and is either returned to its original initial position or moved to a new storage location.
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A MAS (magic angle spinning) NMR (nuclear magnetic resonance) apparatus, with automatic sample supply by a supply unit ( 45 ), is characterized in that an automatic preparation station ( 44 ) for samples is provided, with a rotor storage ( 49 ) having several rotors ( 1 ) for receiving sample material ( 53 ) soaked with NMR solution ( 55 ), a cap storage ( 48 ) with several caps ( 3 ), each cap ( 3 ) being suited for closing a rotor ( 1 ), wherein each cap ( 3 ) has a central axial bore ( 4 ), several movable pins ( 5 ), each being insertable into the central axial bore ( 4 ) of a cap ( 3 ) to close the bore ( 4 ) in the inserted state, a cap handling unit ( 46 b ) which can grip a cap ( 3 ) from the cap storage ( 48 ), move it, and dispose it onto a rotor ( 1 ), a plunger ( 61 ) for inserting a pin ( 5 ) into the bore ( 4 ) of the cap ( 3 ), and a suctioning device ( 62 ) for suctioning excess NMR solution ( 55 ) that escapes from the bore ( 4 ). The apparatus provides simple and automatic preparation of sample units, in particular, closure of rotors with caps.
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BACKGROUND OF THE INVENTION
[0001] CMOS transmission gate (T-gate) switches introduce distortion when used in an instrumentation amplifier (IA). A prior-art transmission gate circuit is shown in FIG. 1 . Transistors MN 1 and MP 1 form the CMOS switch between pins “IN” and “OUT”. This switch is controlled by the “PGATE” and “NGATE” voltages, which are driven out of phase and rail to rail (0-5V) by two digital inverters.
[0002] The off-resistance of this switch is essentially infinite (>1000 meg). The on-resistance is typically between 50 and 5000 ohms, depending on design, and varies with process, supply voltage, and temperature (PVT). Furthermore, the on-resistance also varies with the voltage present at the “IN” and “OUT” terminals. The magnitude of this non-linear variation in resistance is typically significant, on the order of +/−10% of the nominal on-resistance over the full range of applied voltages in a given system. In amplifier circuits where low signal distortion is important, the effects of this non-linear on-resistance must always be mitigated.
SUMMARY OF THE INVENTION
[0003] The present invention provides a variable-gain current conveyor-based instrumentation amplifier without introducing transmission gate distortion.
[0004] An exemplary variable-gain instrumentation amplifier includes a first current conveyor that receives a first input voltage, a second current conveyor that receives a second input voltage, a first resistive element connected between the first and second current conveyors, an amplifier connected to the second current conveyor at an inverting input, and a second resistive element that connects the second current conveyor and the inverting input to an output of the amplifier. At least one of the resistive elements is a variable resistive element.
[0005] In one aspect of the invention, the current conveyors are dual-output trans conductance amplifiers (DOTAs).
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] Preferred and alternative embodiments of the present invention are described in detail below with reference to the following drawings:
[0007] FIG. 1 is a transmission gate circuit formed in accordance with the prior art;
[0008] FIGS. 2 through 4 are conceptual circuits used to show some of the theory behind the present invention; and
[0009] FIGS. 5-1 through 5 - 3 , and 6 through 8 show exemplary current-conveyor instrumentation amplifier circuits formed in accordance with various embodiments of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0010] FIG. 2 illustrates an instrumentation amplifier (IA) 20 . For clarity, dual-output transconductance amplifier (DOTA) symbols 26 , 28 are used to represent current conveyors. One of ordinary skill would understand how to apply current conveyors to the IA 20 . The gain of the IA 20 is defined by the following equation:
[0000] A V =V OUT /( V 1 - V 2 )= R 2 /R 1 (1)
[0011] As shown in FIG. 3 , a IA 40 includes an additional resistor, R 3 , between resistor R 1 and the DOTA 26 . The voltage gain remains the same, A v =R 2 /R 1 , because there is no significant current flowing through the resistor R 3 , especially when using CMOS amplifiers, and no voltage is developed across the resistor R 3 .
[0012] Also in the IA 40 , a resistor R 4 is added between the resistor R 1 and the DOTA 26 . The gain remains the same for small values of the resistor R 4 . In this case, the same current that flows through the resistor R 1 also flows through the resistor R 4 but the voltage that develops across the resistor R 4 does not affect overall gain until the DOTA 26 saturates. For positive input voltages (V 1 -V 2 >0), this happens when the sum of the voltages across the resistors R 4 and R 1 is greater than the voltage across the resistor R 2 . Because the same current, I, flows through all three resistors, this is equivalent to saying that the sum of the resistors R 4 and R 1 must be less than the value of resistor R 2 to avoid amplifier saturation. In other words:
[0000] R 4 +R 1 <R 2 , (2)
[0000] where it is assumed that all amplifiers are connected to the same power supply voltages, all amplifiers have the same saturation characteristics, and one of the inputs is at the ground potential (either V 1 =0 or V 2 =0, the worst case). This is equivalent to the condition:
[0000] R 4 <R 2 −R 1 (3)
[0013] Because A v =R 2 /R 1 , equation (3) is equivalent to equation (4) by substitution.
[0000] R 4 <R 1 ( A v −1) (4)
[0014] In most practical systems, the desired voltage gain is greater than unity and reasonable values of the resistor R 4 will not have any effect on the gain of the IA circuit 40 . In the same way, resistor R 5 does not affect IA voltage gain and small values of resistor R 6 (R 6 <R 2 −R 1 ) do not affect gain, either.
[0015] In a similar manner, FIG. 4 is a IA 60 that includes vestigial resistors R 7 and R 8 that are added to the negative input of the amplifier 24 without affecting the voltage gain of the IA 60 (A v =R 2 /R 1 ). In the IA 60 , reasonable values of the resistor R 7 do not affect the gain because there is no current flowing through the resistor R 7 and the voltage across the resistor R 7 is insignificant (zero for CMOS amplifiers). However, if the value of the resistor R 7 is very large, it may affect high-frequency AC performance.
[0016] The gain of the IA 60 is also not affected by the value of the resistor R 6 , even though there is current flowing through the resistor R 8 , as long as the value is small enough to prevent saturation of the DOTA 26 output. Given the assumption that both amplifiers 26 and 24 are connected to the same power supply, have the same saturation characteristics, and that the node common to the resistors R 2 , R 7 , and R 8 is at zero volts (a virtual ground), then this condition is met when the voltage across the resistor R 8 is less than or equal to the voltage across the resistor R 2 . Because the same current, I, flows through both the resistors R 2 and R 8 , the gain of the IA 60 will not be affected by the value of the resistor R 8 , as long as the value of the resistor R 8 is less than or equal to the value of the resistor R 2 .
[0000] R 8 ≦R 2 (5)
[0017] In one embodiment, as shown in FIG. 5-1 , the gain of IA 120 is changed using a three-terminal potentiometer 124 . A potentiometer 122 is positioned between two DOTAs 126 , 128 that receive two different input voltages (V 1 , V 2 ). The output of the second DOTA 128 is connected to the inverting input of a noninverting amplifier 30 . Functionally, all three circuits from FIGS. 5-1 through 5 - 3 have the following gain. Current conveyors are shown in U.S. Pat. Nos. 8,081,030 and 7,893,759, which are hereby incorporated by reference.
[0000] A v =R 2 /R 1A (6)
[0018] The potentiometer 122 is modeled as a pair of resistors (R 1A +R 1B ) such that the sum of the pair is a constant resistance (R 1 =R 1A +R 1B ). When the wiper of the potentiometer 122 is at one extreme, the resistance between the wiper and the current-carrying end of the potentiometer 122 is a maximum of R 1 (R 1A =R 1 and R 1B =0). In this position, the gain of the IA 120 is equal to R 2 /R 1 . When the wiper is at the other extreme, where R 1A =0 and R 1B =R 1 , the gain of the IA is, in theory, R 2 /0 or infinity. As a practical matter, two effects will prevent the gain from actually going to infinity: (1) the open-loop gain of the input amplifiers and (2) the nonzero wiper contact resistance. Still, very high values of gain, on the order of 1000 or more are feasible.
[0019] As shown in FIG. 5-2 , an IA 140 is configured similarly to the IA 120 , except that the potentiometer 122 receives the wiper from the second DOTA 128 .
[0020] As shown in FIG. 5-3 , a IA 150 includes two potentiometers 152 , 154 , each having a maximum resistance of one half of the maximum resistance of the potentiometer 122 ( FIGS. 5-1 , 5 - 2 ). The IA 150 has the advantage that the values of the noncurrent-carrying resistor segments ½R 1B may be matched if the two potentiometers 152 , 154 are ganged together. In this case, whatever secondary effect these resistor segments have on the high-frequency AC response of the input amplifiers (i.e., DOTAs 126 , 128 ) is equalized and the overall effect on bandwidth is minimized.
[0021] FIG. 6 shows an IA 170 that includes an array 172 of six resistor segments that replace the resistor R 1 from the IAs shown in FIGS. 2 through 4 . This resistor array 172 is connected to CMOS transmission gates SW 1A thru SW 3B or some other active switch. The array 172 of resistor segments and digitally controlled T-gates is implemented on an integrated circuit; whereas the potentiometer approach is not. While this approach is not continuous and limits the IA gain to certain discrete steps, arrays of hundreds or thousands of resistor segments are feasible. In one embodiment, a digital logic block controls the CMOS transmission gates. The digital logic block may, in turn, be controlled by a microprocessor and computer program based on user input.
[0022] In the IA 170 there are three gain settings. Let A 1 denote the first gain setting (only switches SW 1A , SW 1B are on) where A 1 =R 2 /R i . Then, the second gain setting, with only the switches SW 2A , SW 2B conducting, is A 2 =R 2 /R 1 /2=2 A 1 . In a similar manner, the third gain setting, with only the switches SW 3A , SW 3B on, is A 3 =R 2 /R 1 /4=4 A 1 . To summarize, these three gain settings are related, as shown in Table 1. In one embodiment, the IA 170 does not require an array of equal-value resistor segments.
[0000]
TABLE 1
Switch setting
Relative gain
SW 1A , SW 1B
A 1
SW 2A , SW 2B
2 A 1
SW 3A , SW 3B
4 A 1
[0023] A significant consideration is the on-state resistance of the CMOS transmission gates 172 used as the switches shown in FIG. 6 . The on-state resistance is not critical as long as it is less than R 2 −R 1A . This requirement is most difficult to meet (smallest resistance) for the switches SW 1A , SW 1B and becomes progressively easier to meet for the switches SW 2A , SW 2B and then SW 3A , SW 3B which benefit from progressively larger values of gain.
[0024] The transmission gates do not cause distortion in the IA 170 as long as the peak on-resistance is less than R 2 −R 1 . Transmission gates are not typically used in gain switching circuits where direct current flows through them because their on-resistance varies with the operating voltage.
[0025] As shown in FIG. 7 , an IA 200 includes a common three-terminal potentiometer 204 for changing the gain of the circuit 200 . The potentiometer 204 is located between the second DOTA 128 and the amplifier 130 . The gain of the IA 200 is given by equation (7) below where a first resistor segment R 2A of the potentiometer 204 carries direct current and a second resistor segment R 2B does not carry direct current.
[0000] AV=R 2A /R 1 (7)
[0026] In one embodiment, the potentiometer 204 is set so that the first resistor segment R 2A =0 and the second resistor segment R 2B =R 2 . Thus, the gain of the IA 200 is zero: A v =0/R 1 =0. At the other extreme, the potentiometer 204 is set so that first resistor segment R 2A =R 2 (see FIG. 2 ) and the second resistor segment R 2B =0. Thus, the gain of the IA 200 is the same as the nominal gain using fixed resistors: A v =R 2 /R 1 . As a practical matter, the gain of the IA 200 cannot go to exactly zero, due to the finite terminal resistance of the potentiometer 204 . However, the gain may easily be reduced by three or four orders of magnitude from the nominal gain.
[0027] As shown in FIG. 8 , an IA 240 includes an array 244 of three resistor segments and transmission gates, or other switches. Three possible gain settings are listed in Table 2 below where the nominal gain, A 1 , is R 2 /R 1 .
[0028] The IA 240 allows:
[0000]
TABLE 2
Switch setting
Relative gain
SW 3
A 1
SW 2
1/2 A 1
SW 1
1/4 A 1
[0029] In one embodiment, the features shown in FIGS. 5 through 8 may be combined to construct IA circuits whose gains may be varied over a very wide range of values: from zero to infinity with ideal components. Even with real components, the gain may be varied by at least six orders of magnitude. Furthermore, this may be accomplished with a high degree of gain accuracy and no amplifier distortion.
[0030] While the preferred embodiment of the invention has been illustrated and described, as noted above, many changes can be made without departing from the spirit and scope of the invention. Accordingly, the scope of the invention is not limited by the disclosure of the preferred embodiment. Instead, the invention should be determined entirely by reference to the claims that follow.
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A variable-gain current conveyor-based instrumentation amplifier without introducing distortion. An exemplary variable-gain instrumentation amplifier includes a first dual-output transconductance amplifier (DOTA) (i.e., current conveyor) that receives a first input voltage, a second DOTA that receives a second input voltage, a first resistive element connected between the first and second DOTA, an amplifier connected to the second DOTA at an inverting input, and a second resistive element that connects the second DOTA and the inverting input to an output of the amplifier. At least one of the resistive elements is a variable resistive element.
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[0001] This application claims priority under 35 U.S.C. 119(e) from provisional application Ser. No. 60/607,282 filed on Sep. 4, 2004, which is incorporated by reference herein, in its entirety.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to collapsible containers. More particularly, it relates to containers that may be used to carry various small items such as those that may be used for personal hygiene, and may be exposed to a wet environment.
[0004] 2. Prior Art
[0005] Generally, there have been a variety of containers that may be used to carry personal items. Some take up a relatively large space. Others are not suitable for use in wet environments.
[0006] A typical situation in which a variety of personal items, such as personal care items, must be carried is the college dormitory. Often a group of students share a bathroom or shower. Students each have their own personal care items, such as razors, a toothbrush, soap, etc. There generally is no location to leave such items in a commonly used bathroom or shower, nor would students wish to do so.
SUMMARY OF THE INVENTION
[0007] It is an object of the invention to provide a collapsible container that can be used to store and to transport such personal items.
[0008] It is a further object of the invention to provide such a container that is low in cost and usable in a wet environment.
[0009] It is another object of the invention to provide a container that can be exposed to a stream of water, but in which the water will not accumulate.
[0010] These objects and others are achieved in accordance with the invention by providing a container having a generally circular bottom, an outer, continuous wall, a spring for supporting the outer wall in a generally cylindrical form, and a circular top with an opening therein through which articles to be stored or carried may pass through. The bottom is configured with a water drainage hole, so that water that does not escape through the mesh may nevertheless drain from the container. The container may have a series of partitions, preferably of different sizes, for storing articles placed therein.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The foregoing aspects and other features of the present invention are explained in the following description, taken in connection with the accompanying drawing, wherein:
[0012] FIG. 1 is a perspective view of an apparatus in accordance with the invention.
[0013] FIG. 2 is an additional, simplified, perspective view of an apparatus in accordance with FIG. 1 .
[0014] FIG. 3 is an additional, partial perspective view of an apparatus in accordance with FIG. 1 .
[0015] FIG. 4 is an additional, perspective view of an apparatus in accordance with FIG. 1 , shown in its collapsed state.
[0016] FIG. 5 is a perspective view of another embodiment of the invention with internal partitions.
[0017] FIG. 6 is a plan view of the embodiment of FIG. 5 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0018] Referring to FIG. 1 , there is shown a perspective view of a container 10 incorporating features of the present invention, in its expanded form, ready for use. Although the present invention will be described with reference to the embodiments shown in the drawings, it should be understood that the present invention can be embodied in many alternate forms of embodiments. In addition, any suitable size, shape or type of elements or materials could be used.
[0019] The container 10 has a circular bottom 12 formed of a flexible material that may be, for example nylon, a vinyl, or other flexible fabric. At the center of bottom 12 is a grommet 13 , formed of, for example, a non-corroding metal, or a plastic material, that defines an opening 14 through which water may drain. It will be understood that when container 10 is used to hold items, such a personal care items, bottom 12 will be displaced slightly downward (in FIG. 1 ) due to the weight of such items, and opening 14 , located at the center of bottom 12 , will be in an optimum position to provide excellent drainage.
[0020] The outer cylindrical wall 16 of container 10 can be made of a mesh formed of, for example, nylon, having substantially circular openings with diameters of about 0.125 inches. It will be understood that such opening will facilitate drainage of water through the side of container 10 , rather than from the bottom. However, due to the flexible nature of the bottom, a concavity for the accumulation of water would be formed with any item stored therein. Thus opening 14 is still necessary to assure proper drainage. However, wall 16 may be made of a continuous fabric, without openings therein. The opening 14 in bottom 12 will still assure excellent drainage of water.
[0021] Container 10 may be configured with a top 18 having a generally oval opening 20 formed therein through which the items to be stored or carried in container 10 may pass. Alternatively, the opening may encompass substantially the entire top.
[0022] In that region where the periphery of top 20 connects to wall 16 , a continuous circular pocket 22 is formed. Further, in that region where the periphery of bottom 12 connects to wall 16 , a continuous circular pocket 24 is formed. The interiors of pocket 22 and pocket 24 are connected by a continuous pocket 26 (not shown in FIG. 2 ) which may be sewn to the outside of wall 16 so as to spiral up wall 16 as shown in FIG. 1 .
[0023] Container 10 is maintained in the expanded state shown in FIG. 1 by a spring wire (not shown). Two turns of one end of this spring are disposed in pocket 22 , and two turns of the other end of this spring are disposed in pocket 24 . Approximately two turns of the center of this spring are disposed in pocket 26 . A short length of plastic tubing (not shown) is disposed in each of pockets 22 and 24 . The respective ends of the wire are received in these lengths of tubing so that no sharp point is available to tear the fabric from which pockets 22 and 24 is formed. The fit into these tubings should be relatively tight to assure that there is little chance of their moving with respect to the wire so that the respective ends of the wire are removed from the tubing. On the other hand the fit should not be so tight as to make assembly unduly difficult.
[0024] Container 10 may have a handle 28 , comprising, for example a textured nylon fabric, sewn to the joining region of top 20 and pocket 22 , at each end thereof. Further, for reasons of appearance, and to add a bit of strength, a fabric strip 30 may be sewn along the length of container 10 (preferably on the outside surface of wall 16 , but under pocket 26 , at the intersection of strip 30 and pocket 26 ), extending from pocket 22 to pocket 24 .
[0025] Container 10 may be collapsed by merely pushing bottom 12 and top 20 toward one another. The spring is collapsed, and container 10 assumes a pancake shape shown in FIG. 4 .
[0026] For purposes of transportation for sale, or for transportation by, for example a student from home to college, container 10 may be kept in the collapsed state by using an elastic band (not shown). Alternatively, handle 28 may be made somewhat shorter than shown, and of an elastic material, and used for this purpose.
[0027] While the container has been described with one opening 14 , it will be understood that bottom 12 may have a plurality of similar openings disposed in any one of several geometric arrays. The exact configuration is not critical, as long as adequate drainage of water is possible.
[0028] The collapsible container in accordance with the invention may be constructed in a variety of sizes. In accordance with one embodiment, the container is approximately 7.5 inches in diameter and 11.75 inches in its expanded state shown in FIG. 1 . It may be collapsed so that when in the state shown in FIG. 4 , it is less than 0.5 inch high, thus facilitating storage, shipping in quantity, and carrying during a move from one location to another.
[0029] The embodiment of the invention illustrated in FIG. 5 and FIG. 6 may be a container 50 of approximately eight inches in diameter and approximately six inches high, and having a handle 52 . A first vertical partition 54 generally separates the container 50 into a first compartment 56 and a second compartment shown generally as 58 , with compartment 56 being somewhat larger than compartment 58 . A second vertical partition 59 generally separates the second compartment 58 into a two compartments 60 and 62 , with compartment 60 being somewhat larger than compartment 62 . The result is that various items 70 ( FIG. 5 ), to be placed in container 50 , may be organized and stored in a compartment of the most appropriate size for the item. As for the previously described embodiment, a grommet 13 , formed of, for example, a non-corroding metal, or a plastic material, defines an opening 14 through which water may drain.
[0030] It should be understood that the foregoing description is only illustrative of the invention. Various alternatives and modifications can be devised by those skilled in the art without departing from the invention. Accordingly, the present invention is intended to embrace all such alternatives, modifications and variances.
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A container having a generally circular bottom, an outer, continuous wall, a spring for supporting the outer wall in a generally cylindrical form, and a circular top with an opening therein through which articles to be stored or carried may pass through. The bottom is configured with a water drainage hole, so that water that does not escape through the mesh may nevertheless drain from the container. Internal partitions may be provided to help organize item to be carried or stored in the container.
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This application claims the benefit of the Korean Patent Application No. 10-2004-0001681, filed on Jan. 9, 2004, which is hereby incorporated by reference as if fully set forth herein.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a digital filter capable of computing a tap without output delay due to the filter operation in a symbol time, and a digital broadcasting receiver having the same.
2. Background of the Related Art
A digital filter based on the LMS (Least Mean Square) adaptive algorithm is a filter capable of updating or adapting coefficients on an ongoing basis. The LMS adaptive digital filter is usually used for an equalizer or a noise eliminator housed in a digital broadcasting receiver, in order to compensate the distortions generated by a channel or a system itself.
The LMS adaptive digital filter includes a multiplier and an adder for the coefficient adaptation for each tap, and an additional multiplier for the output (filtering).
FIG. 1 illustrates the general structure of an LMS adaptive filter, more particularly, a 2-tap LMS adaptive filter. As shown in FIG. 1 , the LMS adaptive filter includes four serial delays D 11 , D 12 , D 21 and D 22 , D 11 and D 12 for delaying an input signal x 0 in sequence and D 21 and D 22 for delaying a delayed input signal xd 0 , and a first and a second coefficient updating unit 10 , 20 .
Each of the delays D 11 , D 12 , D 21 and D 22 operates according to a clock (clk) signal, and a first and a second tap, i.e., the first and the second coefficient updating unit 10 , 20 have the identical structure.
Here, the input signal x 0 is outputted to the delay D 11 and at the same time to a multiplier 14 of the first coefficient updating unit 10 . The delay D 11 delays the input signal x 0 by one clock, and outputs the one-clock-cycle delayed signal to the delay D 12 and a multiplier 24 of the second coefficient updating unit 20 at the same time.
The delayed input signal xd 0 is simultaneously outputted to the delay D 21 and a multiplier 11 of the first coefficient updating unit 10 . The delay D 21 delays the delayed input signal xd 0 by one clock, and outputs the delayed signal simultaneously to the delay D 22 and a multiplier 21 of the second coefficient updating unit 20 . The delay D 12 delays the delayed signal x 1 , which was delayed by the delay D 11 , by one clock before outputting the signal. The delays D 22 delays the delayed signal xd 1 , which was delayed by the delay D 21 , by one clock before outputting the signal.
The multiplier 11 of the first coefficient updating unit 10 multiplies the delayed input signal xd 0 by a feedback error signal e, and outputs the result to an adder 12 . The adder 12 adds an old coefficient c 0 to the output from the multiplier 11 for the coefficient update, and outputs the updated coefficient to a delay 13 . The delay 13 delays the updated coefficient in the adder 13 by one clock, and outputs the delayed coefficient to the adder 13 and the multiplier 14 . The multiplier 14 then multiplies the output from the delay 13 by the input signal x 0 to obtain a first output y 0 .
The multiplier 21 of the second coefficient updating unit 20 multiplies the delayed input signal xd 1 by a feedback error signal e, and outputs the result to an adder 22 . The adder 22 adds an old coefficient c 0 to the output from the multiplier 21 for the coefficient update, and outputs the updated coefficient to a delay 23 . The delay 23 delays the updated coefficient in the adder 23 by one clock, and outputs the delayed coefficient to the adder 23 and the multiplier 24 . The multiplier 24 then multiplies the output from the delay 23 by the input signal x 1 to obtain a second output y 1 . That is, the outputs y 0 and y 1 are obtained by multiplying the input signals (x 0 , x 1 ) by the coefficients (c 0 , c 1 ) for each tap, respectively.
Recently long-term fading channels are often found because of temporally distant media like ground wave digital TVs. Thus the fading problem should be resolved to facilitate the broadcast receiving operation. However, to compensate the long-term fading by the temporally distant media a multi-tap equalizer or a noise eliminator.
Unfortunately though, the size of the multi-tap filter is so big that the implementation of the filter becomes difficult.
SUMMARY OF THE INVENTION
Accordingly, the present invention is directed to a digital filter and digital broadcasting receiver having the same that substantially obviates one or more problems due to limitations and disadvantages of the related art.
An object of the present invention is to provide a digital filter and digital broadcasting receiver having the same, in which the number of operators for a plurality of taps is reduced and filter output is obtained within a clock period, whereby the filter size problem found in a related art LMS adaptive filter can be resolved.
Particularly, the present invention is characterized of obtaining filter output within a clock period, using one multiplier and one adder to perform coefficient update for a plurality of taps, wherein the multiplier performs the output operation for each tap, and thereby reducing the number of multipliers and adders inversely proportional to the number of taps being operated for one clock period.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, there is provided a digital filter, including: a first data input unit for sequentially delaying input data for a clock period, and sequentially and selectively outputting one of the input data and delay values for the calculation of a filter output value; a second data input unit for sequentially delaying a delayed input data for a clock period, and sequentially and selectively outputting one of the input data and delay values for coefficient update; a multiplier for multiplying the data value that is sequentially and selectively outputted from the second data input unit by an error value; a coefficient update unit for sequentially updating a coefficient by adding an output from the multiplier to an old feedback coefficient, storing updated coefficients in each delay that operates synchronously with a clock signal with a phase difference of 1/N period (N is the number of filter taps), and feedbacking a sequentially selected updated coefficient as the old coefficient; and an output unit for multiplying updated coefficients sequentially and selectively outputted from the coefficient update unit by data sequentially and selectively outputted from the first data input unit, storing in each delay which operates synchronously with a clock signal with a phase difference of 1/N period, adding all outputs from the delays for a predetermined summation period, and outputting the summed value.
In the exemplary embodiment, the first data input unit includes: N-number of serial delays for synchronizing the input data with the clk and sequentially delaying the data; a selection part for sequentially selecting, according to a selection signal sel, one of the input data x 0 and delay values that are delayed respectively by the N-number of delays, and outputting the selected value to the output unit.
In the exemplary embodiment, the second data input unit includes: N-number of serial delays for synchronizing the delayed input data xd 0 with the clk and sequentially delaying the data; a selection part for sequentially selecting, according to a selection signal sel, one of the delayed input data x 0 and delay values that are delayed respectively by the N-number of delays, and outputting the selected value to the output unit.
In the exemplary embodiment, the coefficient update unit includes: an adder for adding an output from the multiplier to an old feedback coefficient and thereby, updating the old coefficient; N-number of parallel delays, each operating synchronously with a clock signal clk 1 ˜clkN−1, clk with a phase difference of 1/N period and storing the updated coefficient; and a selection part for sequentially selecting, according to a selection signal sel, one of outputs from the N-number of parallel delays, and simultaneously feedbacking the selected value to the adder and outputting the value to the output unit.
In the exemplary embodiment, the output unit includes: a multiplier for multiplying a data value that is sequentially and selectively outputted form the first data input unit by an updated coefficient that is sequentially selectively outputted from the coefficient update unit; N-number of parallel delays, each operating synchronously with a clock signal clk 1 ˜clkN−1 with a phase difference of 1/N period, and storing and outputting the multiplication result of the multiplier; and an adder for adding, for the predetermined summation period, outputs from the (N−1)-number of delays and a N-th output value outputted without delay and thereby, obtaining a final output.
It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings:
FIG. 1 is a schematic block diagram of a related art 2-tap digital filter;
FIG. 2 is a schematic block diagram of an N-tap digital filter according to the present invention;
FIG. 3 illustrates operation timing diagrams of a procedure for updating coefficients in the N-tap digital filter of FIG. 2 ; and
FIG. 4 illustrates operation timing diagrams of a filter output procedure in the N-tap digital filter of FIG. 2 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.
The present invention provides an improved filter architecture computing a plurality of taps within a symbol time by sharing adders and multipliers so that the size of a multi-tap filter can be reduced. The present invention filter is very useful for an LMS adaptive digital filter used in a time domain equalizer or a noise eliminator in a VSB digital television receiver.
FIG. 2 is a detailed block diagram of an LMS adaptive digital filter, more particularly an N-tap LMS adaptive digital filter (N is an arbitrary number), according to the present invention.
As shown in FIG. 2 , the digital filter includes a first data input unit 100 for delaying input data x 0 sequentially, and sequentially and selectively outputting one of the input data x 0 and delay values for the calculation of a filter output value; and a second data input unit 200 for delaying a delayed input data xd 0 sequentially, and sequentially and selectively outputting one of the input data xd 0 and delay values for use with coefficient updating. In addition, the digital filter includes a multiplier 300 for multiplying the data value that is sequentially and selectively outputted from the second data input unit 200 by an error value; a coefficient update unit 400 for updating a coefficient by adding an output from the multiplier 300 to an old feedback coefficient, storing updated coefficients in each delay that operates synchronously with a clock signal with a phase difference of 1/N period, and feedbacking a selected updated coefficient as the old coefficient; and an output unit 500 for multiplying updated coefficients sequentially and selectively outputted from the coefficient update unit 400 by data sequentially and selectively outputted from the first data input unit 100 , storing in each delay which operates synchronously with a clock signal with a phase difference of 1/N period, adding all outputs from the delays, and outputting the summed value.
The first data input unit 100 includes N number of serial delays 111 - 11 N operating synchronously with a clock signal clk and sequentially delaying an input data x 0 ; and a selection part 120 for sequentially selecting, according to a selection signal sel, one of the input data x 0 and delay values delayed respectively by the delays 111 ˜ 11 N, and outputting the selected value to the output unit 500 . The clk is a symbol clock in each clock period.
The second data input unit 200 includes N number of serial delays 211 ˜ 21 N, each operating synchronously with a clock signal clk and sequentially delaying a delayed input data xd 0 ; and a selection part 220 for sequentially selecting, according to the selection signal sel, one of the delayed input data xd 0 and delay values delayed respectively by the delays 211 ˜ 21 N, and outputting the selected value to the multiplier 300 . The delayed input signal xd 0 is generated by delaying the input signal x 0 for at least one symbol clock.
The coefficient update unit 400 includes an adder 410 for adding an output from the multiplier 300 to an old feedback coefficient and thereby, updating the old coefficient; N-number of parallel delays 421 ˜ 42 N, each operating synchronously with a clock signal clk 1 ˜clkN−1, clk with a phase difference of 1/N period and storing the updated coefficient; and a selection part 430 for sequentially selecting, according to a selection signal sel, one of outputs from the N-number of parallel delays 421 ˜ 42 N, and simultaneously feedbacking the selected value to the adder 410 and outputting the value to the output unit 500 . It is assumed that each of the N-number of delays 421 ˜ 42 N receives only an input signal at a rising edge of a clock and outputs the signal through an output terminal, and tends to maintain its original state. Examples of the clocks inputted to the clock terminals of the N-number of delays 421 ˜ 42 N include clk 1 ˜clk (N−1), and clk. Here, a clock period represents a symbol time, and clk 1 represents a delayed clk by 1/N period. In like manner, clk 3 represents delayed clk by 3/N period, and clk(N−1) is a delayed clk by (N−1)/N period.
The output unit 500 includes a multiplier 510 for multiplying a data value that is sequentially and selectively outputted form the first data input unit 100 by an updated coefficient that is sequentially selectively outputted from the coefficient update unit 400 ; and N-number of parallel delays 521 ˜ 52 N−1, each operating synchronously with a clock signal clk 1 ˜clkN−1 with a phase difference of 1/N period, and storing the multiplication result of the multiplier 510 . Again it is assumed that each of the N-number of delays 521 ˜ 52 N−1 receives only an input signal at a rising edge of a clock and outputs the signal through an output terminal, and tends to maintain its original state. Examples of the clocks inputted to the clock terminals of the N-number of delays 521 ˜ 52 N−1 include clk 1 ˜clk (N−1). As aforementioned, a clock period represents a symbol time, and clk 1 represents a delayed clk by 1/N period.
Also, the identical selection signal sel is inputted to the first and the second data input unit 100 , 200 , each of the selection parts 120 , 220 , and the selection part 430 of the coefficient update unit 400 , respectively. The selection signal sel is generated sequentially by dividing a symbol time by the number of taps (N). That is to say, N-number of selection signals sel are produced within a symbol time.
FIG. 3 illustrate operation timing diagrams depicting the relation between clocks clk, clk 1 ˜clk(N−1), the selection signal sel, and a procedure for updating coefficients in the LMS adaptive filter. As shown in the drawings, a new coefficient (c) is calculated sequentially according to the selection signal sel, and the new coefficient is synchronized to a clock signal clk, clk, . . . , and clk(N−1) with a phase difference by 1/N period, and stored in each of the delays 421 ˜ 42 N as new c 0 , new c 1 , . . . , and newc(N−1).
FIG. 4 illustrate operation timing diagrams depicting the relation between clocks clk, clk 1 ˜clk(N−1), the selection signal sel, and output signals.
According to the digital filter of the present invention, a total of N+1 signals (from the input signal x 0 to xN) are selectively outputted, according to the selection signal sel, from the selection part 120 of the first data input unit 100 , and a total of N+1 signals (from the delayed input signal xd 0 for coefficient update to xdN) are selectively outputted, according to the selection signal sel, from the selection part 220 of the second data input unit 200 . At this time, each of the signals is transferred to the selection parts 120 , 220 , respectively, through the delays 111 ˜ 11 N, 211 ˜ 21 N operating synchronously with the clock signal clk. In other words, the period of a clock signal clk is equal to a symbol time.
The signals which are selectively outputted from the first data input unit 100 are outputted to the multiplier 510 of the output unit 500 . Also, the signals which are selectively outputted from the second data input unit 200 are outputted to the multiplier 300 .
In the multiplier 300 the output data from the second data input unit 200 are multiplied by an error value (e), and the multiplication result is outputted to the adder 410 of the coefficient update unit 400 . As such, even though the related art filter required multipliers as many as filter taps, the present invention filter shares a single multiplier 300 regardless of the number of taps available. Here, the error value (e) remains the same for a symbol time.
The adder 410 of the coefficient update unit 400 adds the output of the multiplier 300 to an old feedback coefficient for coefficient update, and outputs the new coefficient to each of the parallel delays 421 ˜ 42 N. The updated coefficients are stored in the delays 421 ˜ 42 N that are activated by corresponding clock signals (clk, clk 1 ˜clkN−1).
In other words, the delays 421 ˜ 42 N are designed to operate synchronously with clocks (clk 1 ˜clkN−1, clk) that are delayed from clk by 1/N period in sequence with respect to N-number of coefficients (c 0 ˜c(N−1)). Updated coefficients through the adder 410 are activated by corresponding clocks and stored in the delays, respectively. Here, clk 1 represents a delayed clk by 1/N period, clk 2 represents delayed clk by 2/N period, and clk(N−1) is a delayed clk by (N−1)/N period. The rest of the clocks are delayed likewise.
For example, suppose the selection part 220 of the second data input unit 200 outputs a delayed input signal xd 0 that was delayed by the same selection signal (i.e., sel=0) as in FIG. 3( d ). This delayed input signal xd 0 is then multiplied, at the multiplier 300 , by the error value (e) and outputted to the adder 410 of the coefficient update unit 400 . The adder 410 of the coefficient update unit 400 adds an old feedback coefficient to the output value (=e*xd 0 ) of the multiplier 300 , thereby updating the coefficient. At this time, the old coefficient which is feedbacked to the adder 410 becomes co by the selection signal (i.e., sel=0) inputted to the selection part 430 of the coefficient update unit 400 . Thus, the new coefficient outputted from the adder 410 becomes co + e*xd 0 as in FIG. 3( e ).
The updated coefficient co + e*xd 0 is outputted simultaneously to those N-number of parallel delays 421 ˜ 42 N. However, the N-number of delays 421 ˜ 42 N are designed to be activated at a rising edge only. In addition, different clock signals are inputted to the delays 421 ˜ 42 N, respectively. This means that the new coefficient is stored only in the delays which are activated when the updated coefficient co + e*xd 0 is outputted.
Referring back to FIG. 2 , clk 1 is inputted to the first delay 421 , where the clk 1 as shown in FIG. 3( b ) is a delayed clk by 1/N period.
As such, when the updated coefficient co + e*xd 0 is outputted only the first delay 421 is activated at a rising edge of the clk 1 , and stores the coefficient co + e*xd 0 therein and at the same time outputs the coefficient co + e*xd 0 to the multiplier 510 of the output unit 500 through the selection part 430 . Then the selection signal sel inputted to each selection part 120 , 220 , 430 is changed to sel=0 as shown in FIG. 3( d ). Hence, the selection part 430 selects a second old coefficient c 1 and feedbacks the c 1 to the adder 410 . As illustrated in FIG. 3( f ) the first delay 421 maintains the input coefficient co + e*xd 0 until a next rising edge of the clk 1 . In the course of this operation, the rest of the delays 422 ˜ 42 N remain inactive, none of them receiving the new input co + e*xd 0 .
The multiplier 510 of the output unit 500 multiplies the updated coefficient that is selectively outputted from the selection part 430 of the coefficient update unit 400 by the output data from the first data input unit 100 , and outputs the multiplication result to the N-1 parallel delays 521 ˜ 52 N−1. More specifically speaking, the multiplier 510 multiplies the updated coefficient co + e*xd 0 outputted from the coefficient update unit 400 by the input signal x 0 that is selectively outputted from the selection part 120 of the first data input unit 100 according to the selection signal (i.e., sel=0), and outputs the multiplication result to each of the delays 521 ˜ 52 N-1. As described before, the delays 521 ˜ 52 N−1 are designed to be activated at a rising edge only. In addition, different clock signals are inputted to the delays 521 ˜ 52 N−1, respectively. This means that the multiplication result is stored only in the delays which are activated when the multiplication result is outputted from the multiplier 510 .
Here, the clock inputted to the first delay 521 among the delays 521 ˜ 52 N−1 is clk 1 as shown in FIG. 4(B) . Therefore, the multiplication result y=co*x 0 from the multiplier 510 is inputted and stored only in the first delay 521 that is activated at a rising edge of the clk 1 as shown in FIG. 4( f ), and at the same time outputted through the output terminal. As depicted in FIG. 4( f ) the first delay 521 maintains the input value y˜co*x 0 until a next rising edge of the clk 1 . In the course of this operation, the rest of the delays 522 ˜ 52 N−1 remain inactive, none of them receiving the multiplication result y=co*x 0 from the multiplier 510 .
Accordingly, as illustrated in FIG. 4( e ), the filter output is sequentially generated through the multiplication (performed by the multiplier 510 ) of the input signal from the first data input unit 100 and the coefficient from the coefficient update unit 400 . A first output y 0 is stored in the delay 521 operating synchronously with the clk 1 , the delayed clk by 1/N period, and outputted at the same time. In like manner, a second output y 1 is stored in the delay 522 operating synchronously with the clk 2 , the delayed clk by 2/N period, and outputted at the same time; and an (N−1)th output y(N−2) is stored in the delay 52 N−1 operating synchronously with the clk(N−1), the delayed clk by (N−1)/N period, and outputted at the same time. The rest of outputs are stored likewise, except for the N-th output y(N−1) whose delayless value is outputted from the output unit 500 as it is.
Each output y 0 ˜yN−1 for an N tap, therefore, can be calculated within the clk, and if the summation of all filter outputs is outputted prior to the next clk it is possible to get the total output of the filter within the clk when the input signal is received. In other words, as shown in FIG. 4( h ), in the summation period prior to the clk, N-tap filter outputs are produced at the same time. If the outputs of every tap are summed up for the summation period, it becomes possible to get the total output of the filter within the clk when the input signal is received. As for the summation an adder (not shown) can be utilized to add the outputs y 0 ˜y(N−2) of the N−1 delays 521 ˜ 52 N−1 and the delayless N-th output y(N−1).
In conclusion, according to the present invention digital filter and digital broadcasting receiver having the same, a single multiplier and a single adder are shared regardless of the number of filter taps to perform coefficient update for each tap, whereby the number of operations is much reduced and the filter output can be obtained within the clk. Thus, the digital filter of the present invention can be very advantageously used for multi-tap filters.
The forgoing embodiments are merely exemplary and are not to be construed as limiting the present invention. The present teachings can be readily applied to other types of apparatuses. The description of the present invention is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art.
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The present invention relates to a digital filter capable of computing a tap without output delay due to the filter operation in a symbol time, and a digital broadcasting receiver having the same. Particularly, filter output is obtained within a clock period, one multiplier and one adder are used to perform coefficient update for a plurality of taps, and the multiplier performs the output operation for each tap, whereby the number of multipliers and adders is reduced inversely proportional to the number of taps being operated for one clock period. Thus, the digital filter of the present invention can be very advantageously used for resolving the filter size problem in multi-tap filters.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Application Serial No. 60/280,273, filed Mar. 30, 2001.
BACKGROUND OF THE INVENTION
The present invention relates generally to shift systems for transmissions and transfer cases of the type used in the driveline of motor vehicles. Specifically, the present invention is directed to a spring-loaded shift fork assembly for use in such shift systems.
It is known in the automobile industry to equip power transfer assemblies (i.e., manual transmissions, transfer cases, etc.) with a shift system having spring-loaded shift devices for completing a delayed gear or mode shift once speed synchronization or a torque break occurs. Examples of conventional spring-loaded shift systems are disclosed in U.S. Pat. Nos. 4,529,080, 4,770,280 and 5,517,876. In each of these patents, a pair of springs are used to provide a bi-directional preload function for effectuating coupling of a dog-type shift sleeve with a desired gearset. While such arrangements are satisfactory for their intended purpose, a need exists to develop simpler, more cost-effective alternatives that provide the desired function while advancing the art.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide an improved shift system for a power transmission device having a spring-loaded shift fork assembly.
As a related object, the shift system of the present invention is adapted for use with the range shift mechanism of a four-wheel drive transfer case.
As a still further object, the shift system of the present invention is adapted for use with a gearshift mechanism of a multi-speed transmission or transaxle.
According to a preferred embodiment of the present invention, a shift system for a transfer case includes a spring-load range fork assembly operable for shifting a range sleeve between two speed range positions. The range fork assembly includes a bracket, a range fork, and a spring assembly. The spring assembly is compressed and inserted into chambers formed in both the bracket and range fork. The range fork assembly is slidably maintained on a shift rail and the range fork is coupled to the range sleeve. An actuator mechanism is provided for causing selective axial movement of the range fork assembly on the rail. During operation of the transfer case, the transmission of drive torque while shifting into either speed range may create a resistance force which impedes the axial movement of the range sleeve. However, the spring assembly allows the bracket to shift and apply a shift force on the range fork. When a torque reversal occurs, the shift force causes the range fork to slide the range sleeve to the desired position.
Additional advantages and features of the present invention will become apparent from the subsequent description and the appended claims, taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Further objects, features and advantages of the present invention will become apparent from the following detailed specification and the appended claims which, in conjunction with drawings, set forth the best mode now contemplated for carrying out the invention. Referring to the drawings:
FIG. 1 is a sectional view of an exemplary four-wheel drive transfer case with which the shift system of the present invention may be utilized; and
FIGS. 2 and 3 are exploded perspective views of the spring-load shift fork assembly associated with the shift system of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
In general the present invention is directed to a shift system of the type used in motor vehicle power transmission devices for effectuating axial movement of a coupling member (i.e., a shift sleeve) to shift between gear ratios or drive modes. Thus, while the present invention is shown specifically associated with the range shift system of a two-speed transfer case, it will be appreciated that the present invention is also applicable for use with the mode shift system of the transfer case as well as for use with the gearshift system of multi-speed gear-change transmissions.
Referring to FIG. 1, an exemplary construction for a two-speed transfer case 10 is shown to be equipped with a shift system 12 according to the present invention. Transfer case 10 also includes: a housing 14 ; an input shaft 16 rotatably supported from housing 14 ; a rear output shaft 18 rotatably supported between input shaft 16 and housing 14 ; a front output shaft 20 rotatably supported from housing 14 ; a planetary gearset 22 driven by input shaft 16 ; a range clutch 24 for selectively coupling one of a high-range output and a low-range output of planetary gearset 22 to rear output shaft 18 , a transfer mechanism 26 driven by front output shaft 20 ; and a mode clutch 28 for selectively coupling transfer mechanism 26 to rear output shaft 18 . As will be detailed, shift system 12 controls actuation of range clutch 24 and mode clutch 28 for establishing various operational drive modes.
Planetary gearset 22 includes: a sun gear 30 driven by input shaft 16 ; a ring gear 32 non-rotatably fixed to housing 14 ; a planet carrier 34 ; and a set of planet gears 36 rotatably supported on pins 38 mounted to planet carrier 34 and which are meshed with sun gear 30 and ring gear 32 . Range clutch 24 includes a range sleeve 40 which is splined for rotation with rear output shaft 18 and axial sliding movement thereon between a high-range (H) position, a neutral (N) position, and a low-range (L) position. In the high-range position, clutch teeth 42 on range sleeve 40 are meshed with clutch teeth 44 on sun gear 30 for establishing a first or direct ratio drive connection between input shaft 16 and rear output shaft 18 such that transfer case 10 operates in a High-Range drive mode. In the low-range position, clutch teeth 42 on range sleeve 40 are meshed with clutch teeth 46 on planet carrier 34 for establishing a second or reduced ratio drive connection between input shaft 16 and rear output shaft 18 such that transfer case 10 operates in a Low-Range drive mode. Finally, with range sleeve 40 in its neutral position clutch teeth 42 are disengaged from clutch teeth 44 on stubshaft 31 and clutch teeth 46 on planet carrier 34 for establishing a non-driven Neutral mode for transfer case 10 .
Transfer mechanism 26 is shown to include a first sprocket 50 rotatably supported on rear output shaft 18 , a second sprocket 52 fixed to front output shaft 20 , and a power chain 54 connecting first sprocket 50 to second sprocket 52 . Mode shift mechanism 28 includes a clutch hub 56 fixed to rear output shaft 18 , a clutch gear 58 fixed to first sprocket 50 , a synchronizer 60 disposed between clutch hub 56 and clutch gear 58 , and a mode sleeve 62 splined for rotation with clutch hub 56 and axial movement thereon between a two-wheel drive (2WD) position and a four-wheel drive (4WD) position. In its 2WD position, mode sleeve 62 is disengaged from clutch gear 58 and transfer mechanism 26 is uncoupled from rear output shaft 18 such that transfer case 10 is operating in a Two-Wheel Drive mode. When mode sleeve 62 is slid axially to its 4WD position, synchronizer 60 is energized to synchronize the speed of first sprocket 50 to that of rear output shaft 18 . Once the synchronization process is complete, mode sleeve 62 is permitted to move into coupled engagement with clutch gear 58 for coupling transfer mechanism 26 to rear output shaft 18 and establishing the Four-Wheel Drive mode.
To provide means for coordinating the axial movement of range sleeve 40 between its three distinct range positions and mode sleeve 62 between its two distinct mode positions, shift system 12 includes: a shift rail 70 mounted to housing 14 ; a spring-loaded range fork assembly 72 supported on shift rail 70 ; a mode fork assembly 74 supported on shift rail 70 ; a sector plate 76 operably coupled to range fork assembly 72 and mode fork assembly 74 ; and a shift actuator 78 for causing controlled rotary movement of sector plate 76 . As seen best from FIG. 1, mode fork assembly 74 includes a mode fork 80 and a biasing spring 82 . Mode fork 80 has a tubular sleeve segment 84 journalled on shift rail 70 and a fork segment 86 extending from sleeve segment 82 with a C-shaped end portion 88 retained in an annular groove formed in mode sleeve 62 . A mode pin 90 is secured to sleeve segment 84 and bears against a mode cam surface 92 formed along an outer edge of sector plate 76 . Cam surface 92 is contoured such that rotation of sector plate 76 via actuation of shift actuator 78 causes corresponding axial sliding movement of mode fork 80 on shift rail 70 . Such axial movement of mode fork 80 results in corresponding axial movement of mode sleeve 62 between its 2WD and 4WD positions. Spring 82 is coaxially mounted on shift rail 70 and acts on mode fork 80 to maintain engagement of mode pin 90 with mode cam surface 92 .
Referring now primarily to FIGS. 2 and 3, range fork assembly 72 is shown to include a range fork 94 , a bracket 96 , and a spring assembly 98 . Range fork 94 includes a cylindrical tubular body segment 100 and a fork segment 102 extending orthogonally from body segment 100 with its C-shaped end portion 104 adapted for retention in an annular groove formed in range sleeve 40 . A pair of disc-like annular end flanges 106 and 108 are formed at opposite ends of body segment 100 . Apertures 110 and 112 are formed through end flanges 106 and 108 , respectively, and are sized to permit sliding insertion of shift rail 70 therethrough. A pair of truncated flanges 114 and 116 are formed between end flanges 106 and 108 and include arcuate support surfaces 114 a and 116 a , respectively, adapted to support shift rail 70 thereon. Thus, body segment 100 of range fork 94 defines three distinct cavities, namely, a first end cavity 118 , a central cavity 120 , and a second end cavity 122 . Gussets 124 extend between body segment 100 and fork segment 102 to stiffen range fork 94 and minimize bending.
Bracket 96 of range fork assembly 72 is shown to include a base segment 126 and a pair of laterally-spaced lug segments 128 and 130 . Lug segment 128 includes a disc-like end flange 132 with an aperture 134 therethrough, and a truncated flange 136 having an arcuate support surface 136 a . Similarly, lug segment 130 includes a disc-like end flange 138 with an aperture 140 therethrough, and a truncated flange 142 having an arcuate support surface 142 a . Apertures 134 and 140 are adapted to permit sliding insertion of shift rail 70 therethrough while support surfaces 136 a and 142 a of truncated flanges 136 and 142 are adapted to support shift rail 70 . In addition, a spring cavity 144 is formed between truncated flanges 136 and 142 .
Spring assembly 98 includes a coil spring 150 and a pair of tubular washer sleeves 152 which are inserted into opposite ends of coil spring 150 . Each washer sleeve 152 has a thin-walled tubular body segment 154 and a radial flange segment 156 extending from one end of body segment 154 . The outer diameter of body segment 154 for each washer sleeve 152 is sized to fit inside coil spring 150 while its inner diameter is sized to permit shift rail 70 to extend therethrough. Thus, body segments 154 act as spring guides for the opposite ends of coil spring 150 . In addition, the end surfaces of coil spring 150 are adapted to engage flange segments 156 of washer sleeves 152 .
The components of range fork assembly 72 are pre-assembled prior to mounting on shift rail 70 . Specifically, spring assembly 98 is compressed and placed in spring cavity 144 of bracket 96 such that a portion of the outer face surface of flange segment 156 on each washer sleeve 152 engages a corresponding inner face surface 136 b and 142 b of truncated flanges 136 and 142 , respectively. Thereafter, bracket 96 is brought into mating engagement with body segment 100 of range fork 94 such that spring cavity 144 is aligned with central cavity 120 to define an enclosed spring chamber. As such, a portion of the outer face surfaces of flange segments 156 on each washer sleeve 152 also engages a corresponding inner face surface 114 b and 116 b of truncated flanges 114 and 116 , respectively, for retaining spring assembly 98 within the spring chamber. In this assembled arrangement, end flange 132 of lug segment 128 is positioned within first end cavity 118 and end flange 138 of lug segment 130 is positioned within second end cavity 122 . Moreover, lug apertures 134 and 140 are colinearly aligned with end flange apertures 110 and 112 as well as with the apertures through washer sleeves 152 so as to permit shift rail 70 to be slid through the aligned apertures for mounting range fork assembly 72 thereon for sliding movement. Since coil spring 150 is compressed prior to installation into spring cavity 144 of bracket 96 , it is preloaded for generating a “self-centering” feature whereby truncated flanges 114 and 116 on range fork 94 are radially aligned with truncated flanges 136 and 142 on bracket 96 , as shown in FIG. 1 . Optionally, spring assembly 98 can initially be installed in center cavity 120 of range fork 94 with bracket 96 thereafter assembled with range fork 94 .
A range pin 160 is secured to base segment 126 of bracket 96 and is retained in a range cam slot 162 formed in sector plate 76 . Thus, rotation of sector plate 76 is adapted to cause sliding axial movement of range fork assembly 72 on shift rail 70 which, in turn, results in axial movement of range sleeve 42 between its H, N and L range positions. Sector plate 76 has mode cam surface 90 and range cam slot 162 arranged to provide coordinated axial movement of mode fork assembly 74 and range fork assembly 72 in response to rotation of an output member 164 of shift actuator 78 . Preferably, sector plate 76 can be rotated to four distinct positions for establishing a Two-Wheel High-Range drive mode (2WD-H), the Four-Wheel High-Range drive mode (4WD-H), the Neutral mode (N) and the Four-Wheel Low-Range drive mode (4WD-L). Shift actuator 78 is shown as a gearmotor/encoder assembly 166 operable to receive an electric shift signal which is indicative of the selected drive mode from a mode selector (not shown) that is controlled by the vehicle operator. Based on the selected mode, shift actuator 78 causes sector plate 76 to be rotated to the desired position. However, the spring-loaded feature of range fork assembly 72 allows axial movement of range fork 94 to lag behind that of bracket 96 , via compression of coil spring 150 , when residual drag or an instantaneous torque lock condition prevents engagement of clutch teeth 42 on range sleeve 40 with the clutch teeth on sun gear 30 or planet carrier 34 . For example, if the vehicle operator desires to shift transfer case 10 from the 4WD-H drive mode into the 4WD-L drive mode, a suitable signal is sent to gearmotor/encoder assembly 166 which causes sector plate 76 to rotate to the corresponding sector position. Such sector rotation does not cause movement of mode sleeve 62 out of its 4WD position but does cause bracket 96 to move axially due to the travel of range pin 160 in range cam slot 162 . Coil spring 150 urges range fork 94 to move axially in concert with bracket 96 . However, if misalignment of clutch teeth 46 on planet carrier 34 with clutch teeth 42 on range sleeve 40 prevents movement of range sleeve 40 to its L position, coil spring 150 is compressed in excess of its preload for applying a biasing load on range fork 94 . Once the misalignment is eliminated, coil spring 150 forces continued axial movement of range fork 94 which, in turn, causes range sleeve 40 to move into its L position with range fork 94 being again centered relative to bracket 96 .
Thus, the single spring configuration of the present invention provides a bi-directional spring-loaded function for accommodating shifts into and out of all of the available ranges. Moreover, this arrangement prevents potential damage to gearmotor/encoder assembly 166 by preventing excessive motor current when a shift can not be immediately completed since sector plate 76 is permitted to rotate to the desired sector position while coil loading spring 150 to subsequently cause movement of range fork 94 and effectuate coupling of range sleeve 40 . In manually-shifted systems, a shift lever can be moved by the vehicle operator to rotate sector plate 76 . While disclosed in association with transfer case 10 , spring-biased range fork assembly 72 can also be used in automatically-shifted (“automated”) manual transmissions and transaxles where a power-operated (i.e., electrical, hydraulic) actuator is used to move a shift sleeve into and out of engagement with constant-mesh gearsets to effectuate a gear change.
While the invention has been described in the specification and illustrated in the drawings with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention as defined in the claims. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment illustrated by the drawings and described in the specification as the best mode presently contemplated for carrying out this invention, but that the invention will include any embodiments falling within the description of the appended claims.
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A shift system for a transfer case including a spring-loaded range fork assembly operable for shifting a range sleeve between two speed range positions. The range fork assembly includes a bracket, a range fork, and a spring assembly. The spring assembly is compressed and inserted into chambers formed in both the bracket and range fork. The range fork assembly is slidably maintained on a shift rail and the range fork is coupled to the range sleeve. An actuator mechanism is provided for causing selective axial movement of the range fork assembly on the rail. The spring assembly allows the bracket to shift and apply a shift force on the range fork. This shift force causes the range fork to slide the range sleeve to the desired range position.
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CROSS-REFERENCE TO RELATED APPLICATION
This is a continuation application, under 35 U.S.C. §120, of copending international application No. PCT/EP2013/076638, filed Dec. 16, 2013, which designated the United States; this application also claims the priority, under 35 U.S.C. §119, of German patent application Nos. DE 10 2012 024 604.8, filed Dec. 15, 2012, and DE 10 2013 002 155.3, filed Feb. 7, 2013; the prior applications are herewith incorporated by reference in their entirety.
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to an electric motor, in particular a brushless electric motor, for driving a motor vehicle component. The electric motor contains a rotor mounted rotatably relative to a stator and an electronics system, which has a punched grid provided with a plastic over-mold and a current path which conducts the motor current and has two current path ends spaced apart from one another forming an interruption point that is bridged by a thermal fuse. The thermal fuse has a spring-loaded contact bridge. In particular, a vehicle component is understood to be a fan wheel for cooling coolant water.
German utility model DE 20 2010 002 664 U1 discloses an electric motor, in particular a DC motor, for driving a motor vehicle component, particularly a fan motor for cooling coolant water, having a rotor and a commutator, against which a brush bears with contact. A punched grid over-molded with plastic forms a current path impressed into an electrical isolation, the current path being connected to a brush. The current path, which conducts the motor current, is interrupted so as to form two current path ends spaced apart from one another, and the interruption point is bridged by a contact spring as thermal fuse.
German patent DE 10 2009 036 578 B3 relates to a thermal fuse, in particular for a power module of a motor vehicle. The thermal fuse has a conductive path, which is arranged on a circuit board and is interrupted by an interruption point, and which has a first conductive path portion and a second conductive path portion in each case adjacent to the interruption point. A contact bridge, which is arranged in the region of the interruption point, has a first contact portion and a second contact portion arranged opposite one another. The contact portions are secured in a first position to the conductive path portions by solder at soldered points. The contact bridge is acted on in the first contact position by a spring force, in such a way that the contact portions are separated from the corresponding conductive path portions when the melting point of the solder is reached. The thermal fuse also has a spring element, which, when the melting point of the solder is reached, causes a movement of the contact bridge, which extends parallel to the circuit board. In the second or tripped position the contact bridge is held in a cage without contacting the first conductive path portion.
SUMMARY OF THE INVENTION
The object of the invention is to specify an electric motor, in particular a brushless electric motor, for driving a motor vehicle component, particularly a fan wheel for cooling coolant water containing a thermal fuse, which on the one hand requires a low component part outlay, and with which on the other hand a simple and/or effective arrangement of the component parts in the manufacturing process is enabled.
For this purpose, the electric motor has a rotor that is mounted rotatably relative to a stator, an electronics system with a punched grid provided with a plastic over-mold having a current path which conducts the motor current. The current path has two current path ends spaced apart from one another forming an interruption point. A thermal fuse has a spring-loaded contact bridge for bridging the interruption point, wherein the contact bridge is held pivotably about an axis that extends perpendicularly to the plane in which the interruption point lies.
In an advantageous embodiment of the electric motor the contact bridge pivots about the pivot axis in the plane of the interruption point. A possibility for the space-saving arrangement of the thermal fuse inclusive of the contact bridge and of the spring element and contact bridge is thus made possible.
In accordance with an expedient development the contact bridge is associated with a separate spring element having a first spring leg and having a second spring leg extending at least approximately at right angles hereto. A structurally simple and particularly effective spring element can thus be provided and placed in the arrangement.
In accordance with a preferred variant the spring legs transition into one another via a spring or leg eyelet, which in particular is open. The spring can thus be arranged pivotably in an axis on a shaft element, for example a pin or the like, and a favorable configuration of the spring can be produced. In the assembled state the spring eyelet of the spring element surrounds the pivot axis coaxially. A joint pivoting of the spring element, or spring leg thereof cooperating with the contact bridge, and the contact bridge about the same pivot axis is thus provided easily and also reliably.
In a further favorable embodiment the first spring leg lies in a storage compartment of the plastic over-mold, whereas the second spring leg bears against the contact bridge under a spring preload. In the starting state the spring legs of the spring element are arranged relative to one another at a suitable angle, such that in the installed state the spring legs are preferably arranged perpendicularly to one another when the second spring leg bears against the contact bridge. The preload of the contact bridge by the spring element is thus produced in a simple and also reliable manner. The separate spring element is suitably fabricated from round wire or flat wire in the manner of a leg spring. An economical possibility is thus provided for producing the spring element.
In accordance with an expedient development the spring element and the contact bridge are coupled via a guide element. The contact bridge is thus guided reliably while it passes through the pivot path. For this purpose, the guide element is suitably formed by a groove in the first spring leg and a spring on the contact bridge. A favorable and practical implementation of the spring element is thus provided, which also enables simple handling with regard to the assembly of the component parts.
In accordance with a suitable embodiment the first spring leg of the spring element is bent at the leg end. A stable hold of the spring element on the contact bridge is thus provided.
In a further advantageous embodiment the pivot axis is shaped in the form of a pin from the plastic over-mold. As a result of this structure, the possibility is created that the spring element, in contrast to the contact bridge, itself is not an active component of the thermal fuse or is only insignificantly an active component of the thermal fuse, such that an electrical current flow is provided only via the contact bridge. The current flow therefore is not influenced by the mechanical properties of the contact bridge.
The contact bridge advantageously has, at both ends, contact surfaces contacted with the respective current path ends, wherein the pivot axis lies in the region of the contact surfaces. The possibility is thus created of bridging the interruption point for conduction, soldering the contact bridge at the current path ends, and at the same time also producing the pivotability of the contact bridge.
Both contact surfaces of the contact bridge are suitably soldered to the current path ends. On the one hand a particularly reliable electrical transfer capability of the current via the contact bridge is thus provided. On the other hand the contact bridge is fixed to the current path ends mechanically reliably. In the case of overheating the solder in the region of both current path ends melts practically at the same time, such that the contact bridge in the event of tripping can be pivoted out about the pivot axis and in the plane of the interruption point. The melted solder joints are practically sheared off during this process, which ensures a reliable interruption of the interruption or contact point bridged by the thermal fuse or contact bridge thereof.
In an expedient variant the contact bridge is configured as, or in the manner of a punched and bent part having a number of bends, which form a middle raised bridge portion. The desired mechanical and/or electrical properties of the contact bridge can thus be provided in a simple manner. In particular, the contact bridge can be adapted to different amperages.
The advantages associated with the invention in particular lie in the fact that a simple, favorable and space-saving possibility for integration of the thermal fuse in the electric motor is created by a tripping of the thermal fuse in the plane of the interruption point.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in an electric motor having a thermal fuse, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
FIG. 1 is a diagrammatic, exploded perspective view of a cooler fan for a motor vehicle with a brushless internal rotor motor with integrated converter electronics system according to the invention;
FIG. 2 is a perspective view of an electronics compartment with an electronics system of an electric motor, with a printed circuit board and a punched grid provided with a plastic over-mold, and with a thermal fuse;
FIGS. 3A and 3B are perspective views of a punched grid before and after the plastic over-mold inclusive of an interruption point to be bridged by the thermal fuse;
FIG. 4 is a perspective view of a detail of the electronics system with the thermal fuse; and
FIGS. 5A to 5C are top plan views showing the thermal fuse with a spring-loaded contact bridge in a contact position, in a pivoted position and in a tripped position.
DETAILED DESCRIPTION OF THE INVENTION
Parts corresponding to one another are provided in all figures with the same reference signs.
Referring now to the figures of the drawings in detail and first, particularly to FIG. 1 thereof, there is shown a fan 1 for a radiator of a motor vehicle in a state removed from one another. The fan 1 includes a fan wheel 2 with a central cap 3 , around an outer circumference of which air-guiding blades 4 (illustrated only in part) are arranged in an evenly distributed manner. The fan 1 also has an electric motor 5 , also referred to as a fan motor, by which the fan wheel 2 is driven in rotation.
The motor 5 is formed generally by a stator 6 , which is wound with a three-phase rotary field winding 7 in the form of coils. The motor 5 also includes a permanently excited rotor 8 , which is mounted rotatably about a motor axis 9 in an interior of the stator 6 . In order to mount the rotor 8 , the motor 5 has two rolling bearings 10 and 11 , which act on the rotor 8 from axially opposite sides. The axial play of the rotor 8 between the two rolling bearings 10 and 11 is spring-loaded here by a spring ring 12 .
The motor 5 also has an approximately disk-shaped motor mount 13 . An electronics compartment 14 is formed in the motor mount 13 on an end face facing away from the fan wheel 2 , a converter electronics system 15 being inserted into the electronics compartment 14 . In order to tightly close the electronics compartment 14 , the motor 5 contains an electronics compartment lid 16 , also referred to hereinafter as a housing lid.
The rotor 8 is formed (in a manner not illustrated in greater detail) by a laminated core, into which permanent magnets are inserted in order to generate an exciting field, wherein the laminated core together with the inserted permanent magnets is over-molded by a plastic coating. Similarly, the stator 6 also consists of a laminated core that is over-molded by a plastic coating.
The motor mount 13 is formed in particular by a one-piece die-cast part made of aluminum. The electronics compartment lid 16 is preferably an injection molded part made of plastic.
On the front side thereof, the rotor 8 is provided with four screw domes 18 , by which the rotor 8 is screwed to the fan wheel 2 in the assembled state. The motor 5 and therefore the entire fan 1 is secured to the vehicle via the motor mount 13 , which for this purpose is provided with three screw tabs 19 protruding from the outer circumference of the mount. The motor 5 is a brushless, self-cooled internal rotor motor.
FIG. 2 shows a perspective illustration of the electronics compartment 14 with inserted electronics system 15 . The electronic system 15 has an over-molded punched grid 20 and a circuit board or printed circuit board 21 fitted with electrical component parts. The electric motor 5 is operated by a bridge circuit (B 6 circuit), which is implemented in the over-molded punched grid 20 . For this purpose the over-molded punched grid 20 has a number of switchable semiconductor components 22 , by which current is supplied alternately to the three phase windings of the field winding 7 of the electric motor 5 . The electrical current used for this purpose is provided by a DC source in a manner not illustrated in greater detail.
The three phase windings of the field winding 7 of the electric motor 5 are connected for example in a delta connection via capacitors 23 . In other words each two electrically adjacent phase windings are electrically connected to one another at a motor-side contact point and in each case are in turn electrically contacted via a bridge-side contact point to a bridge branch of the bridge circuit. The windings are produced from a lacquered copper wire and are wound centrally to form a coil.
The over-molded punched grid 20 , additionally to the semiconductor components 22 and the capacitors 23 , also has a thermal fuse 24 . The thermal fuse 24 protects the electric motor 5 against overheating and fire risk. If the motor 5 overheats, the thermal fuse 24 thus trips, and current can no longer flow to or from the motor 5 . Connections 25 , 26 and 27 form an input connection and an output connection for the motor current and two sensor signal outputs, for example for the measurements of the rotational speed (number of revolutions), the direction of rotation and/or the position of the motor 5 .
As is shown in FIG. 2 together with FIGS. 3A, 3B , the input connection 25 is connected to the semiconductor components 22 via the capacitors 23 . A punched grid 28 (see FIG. 3A ) provides conductive paths and is electrically insulated by a plastic over-mold 29 (see FIG. 3B ). The punched grid 28 or these conductive paths conducts/conduct the motor current I M .
FIG. 4 shows the thermal fuse 24 in an enlarged illustration. The thermal fuse 24 connects the current path ends 30 , 31 conducting the motor current I M to one another via an interruption point 32 of the punched grid 28 . The thermal fuse 24 is formed from a contact bridge 33 , which connects two contact points 34 , 35 of the punched grid 28 to one another. The contact bridge 33 itself has contact points 36 and 37 , which are connected by a soldered joint to the contact points 34 , 35 of the punched grid 28 . The soldered points contact the current path ends 30 and 31 to one another electrically via the contact bridge 33 and connect the contact bridge 33 mechanically to the contact points 34 and 35 to form a mechanically fixed connection.
In order to provide the function of the thermal fuse 24 , a separate spring element 38 is provided, which preloads the contact bridge 33 by a first spring leg 39 and is inserted in a storage compartment 41 of the plastic over-mold 29 by a second spring leg 40 . The spring element 38 is deformed in this position in such a way that the spring legs 39 and 40 are arranged practically at right angles relative to one another. Both spring legs 39 and 40 are interconnected via a leg eyelet 42 .
The spring element 38 and the contact bridge 33 are also mounted rotatably about an axis 43 , which is perpendicular to the plane in which the interruption point 32 lies. The axis 43 is formed from the over-mold 29 as a rotary or pivot pin 44 . Here, the leg eyelet 42 is arranged coaxially with respect to the pin 44 and thus with respect to the pivot axis 43 .
The contact bridge 33 is formed in the manner of a punched and bent part having a number of bends, which form a middle raised bridge portion. The spring element 38 can be produced from round wire or also flat wire. No current flows via the spring element 38 , since the pin 44 is formed from the insulating over-mold and the spring element 38 is fitted thereon.
The first spring leg 39 of the spring element 38 has a bend 45 at the leg end, which bend guides the contact bridge 33 in the event of tripping. In addition, the thermal fuse 24 also contains a guide element 46 in the form of a groove/spring connection. Here, the spring element 38 in the event of tripping guides the contact bridge 33 during the pivot over the pivot path thereof. The groove 46 a is formed here on the contact bridge 33 , and the spring 46 b is located on the first spring leg 39 of the spring element 38 .
On the basis of FIGS. 5A to 5C it is shown how, in the event of tripping once the solder of the soldered points has melted, the contact bridge 33 and also the spring element 38 pivot about the pin 44 and thus about the axis. The pivot axis 43 lies here in the vicinity of the contact surface 37 . There, the contact bridge 33 has a bore, through which the pin 44 is passed.
The thermal fuse 24 trips in particular in the event of an over-temperature, in that the solder melts and the contact bridge pivots through a combined rotary and shearing movement on account of the spring force of the spring element 38 , such that the interruption point 32 bridged by the preloaded contact bridge 33 is interrupted. The contact bridge 33 pivots in the event of tripping from a first position (contact position) into a second position (tripped position), wherein the pivot movement is performed about the pivot axis 43 and in the plane of the interruption point 32 .
The invention is not limited to the above-described exemplary embodiments. Rather, other variants of the invention can also be derived herefrom by a person skilled in the art without departing from the subject matter of the invention. In particular, all individual features described in conjunction with the individual exemplary embodiments can also be combined with one another in a different way without departing from the subject matter of the invention.
The following is a summary list of reference numerals and the corresponding structure used in the above description of the invention:
1 fan 2 fan wheel 3 cap 4 air-guiding blade 5 fan/motor 6 stator 7 rotary field winding 8 rotor 9 motor axis 10 rolling bearing 11 rolling bearing 12 spring ring 13 motor mount 14 electronics compartment 15 converter/electronics 16 electronics compartment lid 17 axis pin 18 screw dome 19 end face 20 overmolded punched grid 21 printed circuit board 22 semiconductor component 23 capacitors 24 thermal fuse 25 input connection 26 output connection 27 sensor signal outputs 28 punched grid 29 plastic overmold 30 first current path end 31 second current path end 32 interruption point 33 contact bridge 34 first contact point of the punched grid 35 second contact point of the punched grid 36 first contact point of the contact bridge 37 second contact point of the contact bridge 38 spring element 39 first spring leg 40 second spring leg 41 receiving compartment of the plastic overmold 42 leg/spring eyelet 43 pivot axis 44 pin 45 bend 46 guide element 46 a groove 46 b spring
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An electric motor for driving a motor vehicle component, particularly a fan wheel for cooling coolant water, contains a rotor that is rotatably mounted opposite a stator, and an electronic system. The electronic system contains a punched grid provided with a plastic over-mold and a current path which conducts the motor current and has two current path ends spaced apart from one another forming an interruption point that is bridged by a thermal fuse. The thermal fuse has a spring-loaded contact bridge which is held so as to pivot about an axis that extends perpendicularly to the plane in which the interruption point lies.
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RELATED APPLICATION(S)
[0001] This application is related and claims priority to provisional application(s) (i) having Ser. No. 60/803,805 filed 02 Jun. 2006
BACKGROUND
[0002] 1. Field of Invention
[0003] The present invention is directed to the design and manufacturing of a keyed replaceable lamp that enables, inter alia, end-users to perform a reliable lamp replacement in connection with a reflector system and a respective double end lamp holder, more particularly, the present invention relates to the field of projection display systems and fiber optic illumination systems.
[0004] 2. Description of Background
[0005] U.S. Pat. No. 6,356,700 issued to Strobl (hereafter '700 to Strobl), to an inventor of the present invention involves the utilization of eele-enhanced® reflectors, and pending U.S. patent application Ser. No. 11/419,976 provides a delivery system for removable lamps that increases safety during lamp replacement in connection with eele-enhanced® reflectors, while setting forth the advantages of using keyed lamps with matching keyed lamp mounting systems to provide a safer, alignment free “plug and play” lamp exchange by an end user. FIG. 4. of U.S. patent application Ser. No. 11/419,976 illustrates, for example, a prior art step-in feature on a respective lamp ferrule (also called socket) having a matching step-out feature in a corresponding lamp mounting. However, the present invention illustrates, particularly in the case of an eele-enhanced® reflector system, that such a prior art step-in features of the lamp mounting ferrule require the lamp to be pushed along the lamp axis from the opposite ferrule side against a matching step-out feature of the lamp mounting system to prevent a slow wandering of the optical electrode center of the lamp along the lamps axis due to thermal cycling of lamp, which would cause an undesirable output loss. The small force needed to prevent this position stability error in the prior art needs to be directed towards the center of the envelope, and therefore is fighting against its natural thermal expansion direction resulting increased stress and possible premature envelope failures. The more the lamp gets the used the less the envelope can withstand pressure differentials and the less force it takes to cause its fracture. Therefore, an improved lamp mounting keying system is needed to increase the reliability of a double end mounted end user replaceable lamp.
[0006] This present invention is related to '700 to Strobl, and of the U.S. patent application Ser. No. 11/419,976. The present invention relates in particular to an improved keyed replaceable lamp family that enables a more reliable operation of an end user replaceable lamp in connection with a double ended lamp mounting system. Lifetime and operator safety is further improved if the herein described invention is combined or used in conjunction with '700 to Strobl.
[0007] Therefore, it is first advantage of the present invention to provide a special key family for a double end mounted lamp that mechanically interlocks to a suitably keyed lamp holder without limiting the thermal expansion of the lamp during its on/off operation.
[0008] It is a second advantage of the present invention to provide an alignment free and permanent position stable five-point keyed mounting system between a lamp mounting system and a double end mounted lamp.
[0009] It is a third advantage of the present invention to enable a rotation limiting key for an end user replaceable double end mounted lamps.
[0010] It is a fourth advantage of the present invention to combine the eele-enhanced® lamp reflector module technology with a double end mounted, end-user replaceable arc lamp, and with an installation/removal tool; and to provide additional alignment key and/or lamp type recognition features that facilitate error free end user lamp replacement capability in connection with an eele-enhanced® lamp reflector module or other multi reflector based light collection and concentration systems.
SUMMARY OF THE INVENTION
[0011] The present invention is directed towards prealigned, double end mounted, arc lamps that have two ferrules incorporating precision mechanical key alignment features. In particular, the present invention applies to end-user replaceable lamps in connection with eele-enhanced® reflectors or other multi reflector based light collection and concentration systems, whether installed with or without a protective enclosure as set forth in U.S. patent application Ser. No. 11/419,976.
[0012] In a first embodiment of the present invention, a double end mounted arc lamp is mounted onto two different ferrules (e.g., a Hg, Xe or metal halide arc lamp, DC or AC, low or high pressure). Each ferrule has an axial symmetric alignment feature for two dimensional confinement of the ferrule perpendicular to the lamp direction X. For example, at least an alignment section of the each ferrule preferably has a cross-sectional shape such as a cylindrical, triangular, trapezoidal, rectangular, square or other shape, wherein the alignment section provides a two dimensional mechanical confinement with appropriate lamp mounting reference points or surfaces without limiting the positioning of the ferrule in the lamp axis X direction to a narrow range in X.
[0013] At least one of the ferrules has a raised section (step-out) that provides a unique mechanical stop (key) in the X direction in a mounting feature having a lowered (step-in) section that interlocks with the raised section permitting the lamp to expand away from the X direction location key. In this manner, a five-point alignment key is provided that enables an easy transfer of the alignment of the optical arc center at the lamp factory, where preferably the lamp is aligned with cameras to an optimum given spatial reference location and then is permanently cemented into the respective ferrule pair. Thus, at the same time, a stress free mounting of such a double end mounted lamp into a respective lamp holder mounting pair is procured that further has an accurate standard spatial relationship to the first focal point F 1 of the respective reflector system. Preferably, the five-point mechanical locating keys are integral portions of a respective reflector. For example, the keys are built into the sides or flanges of at least one respective - reflector component. Similarly, additional alignment key features exist between the various reflector components comprising the reflector system.
[0014] In another preferred embodiment of the key system, a mechanical key enables the end user to position the lamp into the lamp mount substantially in only one predetermined rotational way, wherein the position of the lamp is unique with respect to the reflector and the mechanical locating keys are sufficiently defined so as to prohibit a positioning error during lamp insertion into the lamp mount (e.g., left right, up, down, different axial rotation). Moreover, the lamp mounting keys are preferably configured and dimensioned such that the insertion and/or activation (power up) of incorrect lamp types is prevented. For example, for a given illumination system having a cooling solution and power supply, only a narrow range of lamp types are compatible and inadvertent use of incorrect lamp is prevented. This can be accomplished in a plethora of ways, for example, (i) having additional mechanical key features on one or both ferrules, or (ii) by changing the spacing between (a) the two ferrules or (b) of least one of their respective additional key features and/or (iii) alpha numeric key entry into a illumination system, and a check and authorization procedure(s) that enable or disables the power up mode of the lamp power supply.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] In order for the present invention to be clearly understood and readily practiced, the present invention shall be described in conjunction with the drawings set forth herein below:
[0016] FIG. 1 illustrates a prior art keyed, removable, double end mounted lamp having a step-in X location position features;
[0017] FIG. 2 illustrates a keyed, removable, double end mounted lamp having a step-out X location position features;
[0018] FIG. 3 illustrates a schematic view of a preferred keying ferrule/lamp mounting system;
[0019] FIG. 4 illustrates a schematic view of another preferred keying ferrule/lamp mounting system;
[0020] FIG. 5 illustrates a 3D view of a keyed lamp ferrules; and
[0021] FIG. 6 illustrates a detailed view of a lamp mounting system incorporated into reflector component.
DETAILED DESCRIPTION OF THE INVENTION
[0022] The present invention is directed to a keyed, alignment free, removable, double end mounted lamps that are used in connection with a double sided mounting system, such as is used in an eele-enhanced® reflector or other multi reflector systems. In particular, this invention pertains to the field of micro display based projection display systems and fiber optic light sources.
[0023] Historically, eele-enhanced® reflectors have been manufactured with either a Ni electroforming manufacturing processes or a glass molding process. Both manufacturing processes copy the geometrical surface of a respective highly polished metal tool in an inverted (complimentary) manner. The manufacturing processes for such reflector tooling lends itself very naturally to the manufacturing of recessed (step-in) key alignment features on a non-optically relevant surface portion of the respective reflector manufacturing tool; such that they are actually become an integral part of the reflector component and therefore produce the highest accurate keyed alignment features between the optical reference points (focal points) of the respective reflector components and respective keyed lamp mounting locations.
[0024] FIG. 1 illustrates a schematic view of a prior art, alignment free, keyed, removable lamp that has been used an inventor of the present invention in the last few years in connection with Ni electroformed eele-enhanced® reflectors. The two lamp posts 2 containing two Molybdenum foils 3 are connected mechanically and electrically to the envelope 4 which surround in an air tight manner an electrically excitable gas mixture that can be energized with the electrodes 6 and 7 . In the case of an AC arc lamp, the middle point between the tips of the electrodes 6 and 7 form an optical center 20 that needs to be placed near a respective first focal point F 1 of an eele-enhanced® primary reflector. Since the electrode tip location typically changes over the life to the arc lamp often a geometrical reference point RP (often also called optical center) is being used that is typically being derived from the two mass center points of the front portion of the electrode body, not just from the respective electrode tip locations for a brand new arc lamp. In the case of a DC arc lamp with asymmetric cathode and anode electrodes 6 and 7 the respective optical center 20 or reference point RP (as opposite to the center of the envelope 4 ) is typically located closer to the cathode type electrode tip than the respective anode tip.
[0025] The two lamp posts 2 are rigidly cemented to the lamp ferrules 52 and 54 (with the prior art second ferrule 54 having a step-in alignment feature 60 that provided a reference position location in the lamp axis direction X after the optical center 20 has been optically aligned with respect to the mechanical alignment features of the ferrules 52 and 54 to a given standard mechanical spatial reference distance 61 between the mechanical location features and the optical center 20 . The step out feature of the prior art lamp ferrule 52 shown in FIG. 1 is not a location feature. It has been used in the prior art by one of the present inventors to increase the electrical path length from the envelope center to ground to minimize arcing to ground during the ignition period of the arc lamp. The electrical connection of the lamp can be made either with a permanent connected HV cable 56 or with a pin 58 that is seated in a proper spring loaded electrical ferrule (not shown in FIG. 1 )
[0026] This prior art keyed removable lamp design is the most natural evolution from the standard Ni electroforming or glass molding manufacturing process that was historically used in the manufacturing of the prior art eele-enhanced® reflectors with built-in highly accurate ferrule mounting alignment features that are integral parts of the eele-enhanced® primary or retro reflector component, and such features are located on a non-optical critical portion of the reflector flange surface. In other words, since the electroforming or glass molding process is a complementary copy process that copies the inverted shape of a highly polished machined optical tool, the machining process used to manufacture the molding or electroforming tool guides the natural choice of alignment feature selection for the integrated lamp ferrule mounting key features. Since it is easier to remove material the natural result is that the copied mounting tool has alignment features that step-out and therefore the lamp mounting ferrule 54 has a step-in feature 60 that which needs to be pressed in the direction 62 to lock stably into a fixed X reference position, i.e. the pressure needs to come from the first ferrule 52 across the lamp L to the second ferrule 54 to keep the lamp position stable over many lamp turn on cycles.
[0027] However, extended lifetime testing and investigation of various failure modes has historically shown that with the pressure direction 62 compressing the envelope 4 is stressing the envelope and leads to an increased explosion rate over the life of the lamp. This problem increases with lamp age during which the mechanical integrity of the envelope is weakened due to a steadily increasing zone of quartz devitrification.
[0028] FIG. 2 illustrates a first preferred embodiment of the present invention where the prior art step-in alignment feature 60 of the ferrule 54 has been reversed to the step-out feature 80 which has a standard mechanical reference distance 81 against the optical center 70 . While this feature reversal appears on first sight trivial, given the additional complication in tool manufacturing it was clearly not intuitive to those skilled in the art, i.e. including to ourselves, who have been making prior art keyed removable lamp components according to FIG. 1 for years.
[0029] The preferred embodiment of the present invention provides a slight force in the direction 82 against the electrical connection pin 61 or directly against the ferrule 54 to mechanically load the step-out features 80 against a matching step-in feature in a respective lamp mounting system without pre-stressing the lamp in its biggest thermal expansion direction. The preferred embodiment of the invention is independent on whether the respective lamp ferrule mounting system is an integral part of the reflector body or a separate mechanical component that also has a standard fixed spatial relationship to the first focal point of the respective reflector system. In this manner the optical center 70 of the lamp can be prealigned in the lamp factory utilizing the same mechanical key location features of the ferrule 52 and 54 that will be used by an end user for an alignment free (plug and play) precision placement of the optical center 70 near the first focal point F 1 of a respective matched reflector system.
[0030] In another preferred embodiment of the present invention (shown/not shown), the ferrule 52 and 54 each have additional axial symmetric alignment feature section 84 and 86 that allows each respective ferrule to be located precisely and uniquely perpendicular to the lamp axis X, in a corresponding lamp holder. The ferrule 52 is preferably designed in such a manner that the X limit of the ferrule 52 has at least some translation freedom in the lamp axis direction. For example, according to this invention the X position tolerances of the ferrule 52 is greater than the maximum change in expansion length of the lamp during its on (hot) and off (cold) operation mode.
[0031] The preferred mounting system of the present invention (shown/not shown) has at a minimum five precision located mechanical contact points or surfaces, with two for the ferrule 52 and three for the ferrule 54 including the step-out features 80 and the latter is arranged in such a manner that the envelope 4 is free (unrestricted) to expand away from the stepped out features 80 in the X direction. Optionally at least one of the ferrules 52 or 54 has also a X-axis rotational limiting key features that also allows to preserve the axial orientation of the electrode tips as it has been optimally chosen during the manufacturing of the keyed removable lamp. For example, if the orientation of the illumination system utilizing such a keyed removable lamp is known at all times (for example for a rear projection display system application) the preferred rotational orientation of the electrodes 6 in the mounting ferrules 52 and 54 is such that the electrodes are pointed the farthest possible distance from the top of the envelope when its is installed (mounted) inside the projector. This will reduce the devitrification growth rate due to the increased distance from the electrode 6 tips to the top portion of the envelope 4 .
[0032] Alternatively, if the lamp orientation of an end user application is unknown, for example for a front projector that can also be mounted upside down, it is known that the electrode tips need to be put in a plane that is horizontal with respect to gravity to avoid the greater problem that the shortest distance from the electrode 6 tips is for some installations on the top of the envelope (upside down installation). This alignment also minimizes the optical extent of the emission source (étendue) while simultaneously improving the average lifetime (reducing devitrification effects on average), which is particularly beneficial for the smallest size light valves which are most sensitive to an increase in the emission étendue over the life of the lamp.
[0033] In another preferred embodiment of the present invention, the two axial symmetric features 84 and 86 cover at least one portion of a cylindrical surface, and optionally, have either the same or a different diameter, or the mounting ferrules 54 and 52 have additional interlocking key features that prevent an accidental end user left/right inverted lamp installation.
[0034] FIG. 3 is a schematic view of another preferred embodiment of the present invention. The ferrule 54 with the raised (step-out) alignment feature 80 and mounting system step-in feature 90 with the contact surface 91 is shown here with a sloped step-in transition surface 100 instead of the 90° step-out feature shown in FIG. 2 . This is an improvement in the reproducibility of the interlocking alignment features between the locating step-out feature 80 and the mounting step-in feature 90 since the center flat or curved surface portion 100 of the feature 80 and of the sloped flat or curved surface portion 91 allow a more reproducible and more protected contact point so as to minimize if not eliminate the influence of any wear of inside or outside corners 102 , 104 of ferrule 54 on the mechanical interlocking position 81 . Instead, in this preferred embodiment only the protected portion of the two interlocking surfaces 100 and 91 is used for a mechanically interlock. FIG. 3 illustrates the radius of the inner corner 102 of the raised alignment feature is preferably smaller than the radius of the mounting system 103 such that the corners 102 , 104 do not provide any interlocking interference. Similarly, the preferred step height of the raised step 80 is smaller than the step height of the mounting feature 90 so as to prevent the inner corner 106 from mechanically interlocking with the outer corner 104 .
[0035] FIG. 4 illustrates another preferred embodiment of the present invention, with a 90 deg sloped step 108 on the mounting ferrule 54 together with a less than 90 deg sloped lamp holder alignment stop key 90 of the lamp mounting system. This mechanical interlock depends on the contact between a point or line 110 and a flat sloped surface 91 and as long it is mechanically stable it can be used therefore to transfer the standard distance 81 to the focal point FI of a respective reflector. In reality the sharp corner 110 is likely to be somewhat rounded. Thus, according to this invention, it is still possible to utilize somewhat miss matched step-out/step-in features (point to surface or point to point interlocking contacts) as long as the appropriate standard distances 120 between the interaction point/line 110 and the mounting surface 91 are appropriately been set at the lamp factory so that they can be used to transfer the alignment of the optical center 70 at the lamp factory by the end user to the F 1 focal point of the respective mounted lamp reflector system.
[0036] FIG. 5 illustrates another embodiment of the present invention where two matched ferrules 52 and 54 are shown incorporating additional key locating/differentiation features. The axial symmetric features 84 and 86 are shown here with a full cylindrical shape. The second ferrule 54 has a short sloped raised key locating surface 100 that is limited laterally by the tapered feature 111 therefore providing both an X-location position key as well as an axial rotational key lock with a tapered guide that facilitates the proper rotational orientation key lock insertion. The additional rotational lock key 130 and 132 have different widths so that with a matching lamp holding key feature an accidental and improper transposing of ends or more simply, an inverted lamp insertion is prevented by an easy recognizable positive mechanical interlock. The optional partial circumferential disk 140 and 150 provide an increased electrical path in free air to prevent arc over from the electrical center pin that will be inserted through the hole 160 during the lamp assembly process (not shown in FIG. 5 ) and grounded metal reflector during the high voltage ignition phase.
[0037] Additional wings 162 and 164 can also be used to increase the electrical path length while simultaneously allowing forced air to blow over the other side of the lamp axis to cool the top of the envelope. The sloped surface 170 and 172 provides a plurality of purposes, first as an insertion guide key for the alignment surface 100 to prealigned it near its optimum location, and second, as a mechanical interlock which prevents insertion into the holder (for example if it is missing) if the style of the lamp is incorrect. The latter prevents accidental insertion of the incorrect lamp type in to a reflector holder designed for a particular illumination product family.
[0038] The distance between the disk features 140 and 150 can be used in a similar manner to prevent accidental insertion of the incorrect lamp type into a given lamp mount. Additionally, optical color and/or bar code keys, magnetic printed keys, additional recessed step-in and step-out mechanical features, etc. can be incorporated to mark the ferrules 52 and 54 to further prevent accidental use of the incorrect lamp type, especially if the power supply is interlocked to at least one family recognition feature, wherein power up is permitted only when a proper key sequence is recognized. These activation keys could also be entered through a remote keypad or other control button(s) that are part of the illumination product.
[0039] In another embodiment of the present invention, a delivery tool U.S. patent application Ser. No. 11/419,976 is used to deliver the lamp to the lamp mounting while it is protected during the transport. Besides the mechanical key system discussed in the reference, the delivery tool or the related packaging material preferably contains an alpha numeric key sequence that the user gains access to only after removal of the lamp from the delivery tool. This key sequence is then preferably used to further authorize the lamp activation through a software check protocol that recognizes the lamp type and the illumination system, and verifies compatibility there between. Optionally, such sequence may authorize a time limited use of such a lamp to prevent an increase failure rate inside the illumination system caused in whole or impart by an overuse (e.g., beyond a recommended statistical safe operation time) of such a customer replaceable lamp by the end user.
[0040] Ideally the present invention provides a defense against the first line of end user error, namely, a series of mechanical interlocking key features that provide an alignment free lamp insertion, but also prevent the accidental insertion of the incorrect lamp type. Moreover, the present invention provides a second line of defense wherein the design limits the over usage of such a lamp by the end user, by going through a time limiting authorization procedure. This procedure is integrates with the internal software of the illumination product which is reset every time a new lamp is inserted and wherein a respective activation procedure needs to be successful completed to restart the lamp usage timer.
[0041] FIG. 6 illustrates a portion of a lamp mounting system that can be cooperatively connected to ferrules 52 , 54 . The eele-enhanced® retro reflector 200 has an exit hole 202 and a flange 204 with key alignment features 206 that can be used to mechanically align the retro reflector 200 to a respective eele-enhanced® primary reflector and to an optional lamp mounting system (both not shown in FIG. 6 ). A portion of the lamp mounting system matched to a lamp according to the present invention is incorporated as ferrule holders 222 , 224 shown here as semi-cylindrical, axial symmetric surfaces that confine ferrules 52 , 54 perpendicularly to lamp axis X. The step-in sloped surface 230 confined laterally by the two side walls 240 provide the key for locating the step-out feature 100 with the lateral limitation feature 111 , thus providing both a unique stop in the X-axis direction, and a rotational lock in the lamp axis direction. The key features 230 have a standard spatial distance relationship 250 to the first focal point FI of the respective eele-enhanced® reflector system of which reflector 200 is a component thereof.
[0042] Thus, FIG. 6 illustrates the integration of a reflector and a basic keyed double side lamp mounting system. Additional lamp type differentiation keys and/or guiding insertion keys, located for example on the left and/or right side of the ferrule holders 222 , 224 and not shown in FIG. 6 , can be used to limit the end user to insert only the correct lamp type into the proper mounting position.
[0043] All of the above referenced patents; patent applications and publications are hereby incorporated by reference. Many variations of the present invention will suggest themselves to those of ordinary skill in the art in light of the above detailed description. All such obvious modifications are within the full-intended spirit and scope of the claims of the present application both literally and in equivalents recognized at law.
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The present invention is directed to the design and manufacturing of prealigned, keyed, removable, double end mounted arc lamps that enable, inter alia, end-users to perform an alignment free, bare lamp replacement in a lamp reflector module in the field of projection display systems and fiber optic illumination systems.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of PPA No. 60/714,895 filed Sep. 8, 2005 by present inventor.
FEDERALLY SPONSORED RESEARCH
[0002] Not applicable.
SEQUENCE LISTING OR PROGRAM
[0003] Not applicable.
BACKGROUND OF THE INVENTION
[0004] This proposal relates to the aerodynamic wing-lifting structures and closed hydrodynamic circuits with lifting winglets. This proposal deals with chord-telescopic wing-design for open systems of flying vehicles, and closed self-boosting circuits for any kind of motor vehicles. The subject matter is a combined upkeeping technology consisting of aerodynamic and hydrodynamic systems with wing-lifting structures for overcoming various tense situations.
[0005] Some specific problems involved in conventional motor vehicles:
a) Various regular airfoils of flying vehicles contain so-called high-lift devices with multiple flaps, slats, slots, other separate elements. Said mechanical interrupters cause interactions among air circulations, wing-upwashes, wing-downwashes, and, in many cases, motor's incoming airflows and high-speed powerful exhaust-jets. Said interactions lead to various deformations and disturbings of wing-airflows and force high and unsafe speeds for takeoffs and landings needed to compensate said energy losses of airflows around lifting wings. b) Any vehicles need substantial reducing of their sum-general loads, especially in hard portions of operations such as takeoffs and landings for flying means and various road-difficulties for land and other vehicles. c) No motor vehicles use the remarkable high energy ratio which well known closed fluidynamic testing tunnels demonstrate.
[0009] The real knowledge of the Fluidynamic lift nature is not complete even now. For example, two high-experienced specialists D. Anderson and S. Eberhardt, in their book “Understanding Flight” [629.13An2336u; 2001] describe some important miscomprehended problems.
[0010] In other words, the theory of Fluidynamic lift is not perfect. That is why aircrafts can fly but mostly cannot take off and land at appropriate speeds about 20 miles per hour with comfort for people and high reliability for the planes, all their systems and interconnections in multiple high-dynamic operations.
[0011] My proposal solves some of said above problems and presents a combined technology and means for any kind of motor vehicles to be more effective. The actual combined reducing of sum-general loads is substantial, about 50%. It is done by additional lift forces generated in energy preservating and accumulating technology. This technology provides to all parts of all the flows around wings in aerodynamic structures and around winglets in self-boosting hydrodynamic circuits appropriate zones free from any disturbings and energy losses.
[0012] Any prior arts connected with developed in present proposal chord-telescopic curve-tilting smooth-united multisegment lifting aerodynamic wings and their combined and/or independent usage with also developed in present proposal closed loop waved hydrodynamic winglet-circuits providing integrated lift forces were not found.
BRIEF SUMMARY OF THE INVENTION
[0013] It is the object of this proposal to provide:
a. Various, combined and cooperative fluidynamic lift forces for motor vehicles and statis means in order to facilitate their total-sum loading. b. High vehicles' efficiency in developed upkeeping thrifty aerodynamic and self-boosting accumulative hydrodynamic technologies with substantial energy savings. c. Easy, safe and sure overcoming tense situations, connected with heavy load, for any motor vehicles. d. Short, safe, sure take-offs and landings at speeds about 20 miles per hour, more convenient for people, and appropriate for aircraft's' systems and their connections keeping and preserving their reliability.
[0018] The nature and substance of Fluidynamic Lift combined Array, Technology are two fluidynamically similar but independent and combined lifting systems:
built-in hydrodynamic sets for any of motor vehicles and/or static means including aircrafts, trucks, cars, ships, trains, helicopters, elevators, heavy containers, others; outer aerodynamic structures for various flying vehicles like planes, and others.
[0021] Proposed self-boosting accumulative technology of closed loop waved circuit-tunnels with hydrodynamic lifting winglets and curved elbows, and upkeeping thrifty technology with chord-telescopic curve-tilting wings in aerodynamic structures, provide separate and/or combined fluidynamic lift forces for a high effective common load-reducing result.
DRAWING FIGURES
[0022] In the drawings closely related elements have the same numbers but different alphabetic suffixes, numbers of views, and sections according to numbers of figures where they are shown.
[0023] FIG. 1 shows a plan view of a exemplary flying aircraft designed by “Fluidynamic Lift Combined Array, Technology” with:
an aerodynamic structure of multi-segment chord-telescopic wings, and a set of four built-in hydrodynamic closed-loop circuits.
[0026] FIG. 2 is a schematic, turned horizontal, part-section 2 - 2 taken in FIG. 1 .
[0027] FIG. 3 illustrates a side view-section 3 - 3 taken in FIG. 1 , and shows the general design and aerodynamic interactions; simplified contours of hydrodynamic circuits and resulting lifting forces are also shown.
[0028] FIG. 4 shows a plan view 4 from FIG. 3 and illustrates one of said wings in drawn-in state for high cruise speed with minimum drag.
[0029] FIG. 5 shows the same plan view of the same wing of FIG. 4 but in extended state for low speed takeoff or landing with maximum lift.
[0030] FIGS. 6 and 7 show the schematic cross-sections 6 - 6 and 7 - 7 taken in FIGS. 5 and 4 , respectively, illustrating chord-telescopic interactions with curve-tilting displacements of movable smooth-united segments of said wings relatively its static carcass-frame. The coaxial sets of force cylinders, hinges, springs, section chords, angles of attack are also shown.
[0031] FIG. 8 shows the side view-schematic section of the waved hydrodynamic circuit and illustrating its general design lifting winglets, hydrolic pump, closed loop tunnel, cavitation control, bypass, air cooler-set.
[0032] FIG. 9 shows the plan view 9 taken in FIG. 8 .
[0033] FIG. 10 illustrates a cross section 10 - 10 taken in FIG. 8 and shows a preferable design of the closed loop tunnel.
[0034] FIG. 11 shows a schematic side view of an exemplary bus with five built-in hydrodynamic closed loop circuits and their integrated lift forces.
[0035] FIG. 12 is a cross section 12 - 12 in FIG. 11 .
[0036] FIG. 13 is a fragment 13 of FIG. 11 , it shows a partial side section of lifting winglet in upper zone of said circuit's tunnel and general hydrodynamic interactions around said winglet including hydrodynamic and centrifugal lift forces.
REFERENCE NUMERALS AND SYMBOLS IN DRAWINGS
[0000]
20 —Chord-telescopic curve-tilting wing [CTW]
20 A—CTW carcass-frame
20 B—CTW head-segment
20 C—CTW middle for-segment
20 D—CTW tail-segment
20 E—CTW middle aft-segment
20 F—Force cylinder
20 P—Cylinders' power set
21 —CTW—horizontal stabilizer
22 —Fuselage
23 —Vertical stabilizer
24 —Aileron.
25 —Rudder
26 —Thrust Motor
27 —Hinge
28 —Spring
29 —Elevator
30 —Hydrodynamic circuit
30 A—Closed-loop waved tunnel
30 B—Controlled bypass
30 C—Air cooler
30 D—Bottom bend.
30 E—Comb elbow
30 F—Cooling fins
30 L—Operative liquid
30 P—Static pressure piston-valve
31 —Tunnel frame structure
32 A,B,C,D,E—Hydrodynamic lifting winglets
33 A,B—Guide-grids
33 P—Pocket
33 S—Flow straightener
34 C—Wiglet control
34 G—Guide-grid control
35 —Axial-flow propeller pump
35 D—Pump drive
35 M—Pump motor
36 —Visualization
37 —Meters, control
38 —Bus engine
[0076] Reference numerals 20 F, 20 P, 22 , 23 , 24 , 25 , 26 , 27 , 28 , 30 B, 30 C, 30 F, 31 , 35 D, 35 M, 36 , 37 , 38 are conventional units, elements, and structures used in present new combined Fluidynamic lift-technology. Control of regular elements is not shown.
[0077] Aerodynamic Symbols:
—Wing upwash —Wing bending airflow —Tip vortex —Wing downwash-jet C H,Lmax —Extended wing section chord of the wing 20 C H,Dmin —Drawn-in wing section chord of the wing 20 T,L —Angle of attack for takeoff and landing. c,f —Angle of attack for cruise flight —Force cylinders' set common axis —Aerodynamic lift force
[0088] Hydrodynamic and Other Symbols:
Winglet upwash Winglet bending flow Winglet downwash-jet Circuit operative liquid flow Motor incoming airflow Motor thrust jet Winglet hydrodynamic lift force Operative liquid resulting centrifugal lift force Circuit integrated lift force
DETAILED DESCRIPTION OF THE INVENTION
[0098] The Fluidynamic Lift Combined Array, Technology for motor vehicles includes two systems:
an aerodynamic structure of chord-telescopic multisegment smooth-united lifting wings 20 , 21 for flying vehicles, and a set of hydrodynamic circuits 30 comprising closed loop waved tunnels 30 A with lifting winglets 32 and operative liquid 30 L inside said tunnels, for any kind of vehicles and some static means.
Both said systems can work together cooperating each with other in common motor vehicle or separately and independently.
[0101] FIGS. 1 , 2 , 3 illustrate how said systems can be designed and arranged into an exemplary aircraft. There are shown:
an arrangement of lifting wings 20 , 21 with fuselage 22 , thrust motors 26 in order to provide for all acting aerodynamic flows needed clear zones without any interactions and interdisturbings; built in placement of circuits 30 connected with vertical walls of fuselage 22 ; outer aerodynamic lift forces AL, created by wings 20 , 21 , inner integrated hydrodynamic lift forces HL generated in circuits 30 ; clear cooperations of general flows with said aerodynamic structure; vertical stabilizers 23 , ailerons 24 , rudders 25 , elevators 29 are also shown.
[0108] FIGS. 1,3 show the general acting flows with circled symbols UW, BA, DW, V, MA, TJ. The clear nondisturbing cooperative interactions among the all said flows at all their directions and zones are illustrated:
The wings 20 , 21 , and aircraft thrust motors 26 are arranged in the aerodynamic structure in vertically declined order, so Any upper adjacent wing is placed back in airflows direction, and Any lower adjacent wing is placed forward in flight direction.
Therefore, Interaffections and mutual disturbings of airflows bending wings, upwashes, downwashes, vortices and thrust-motor-flows near the flying vehicle are prevented.
[0112] FIGS. 4 , 5 , 6 , and 7 illustrate the general design and chord-telescopic smooth-united operations of said lifting wings 20 , 21 with displacements of their segments 20 B, 20 C, 20 D, 20 E around static carcass-frames 20 A. Said chord-telescopic displacements, are provided by coaxial sets of force cylinders 20 F driven by power sets 20 P.
[0113] The hinges 27 and springs 28 provide needed mini-turns, support and self-adjusting to the segments of the wings 20 , 21 for needed aerodynamic positions. This gives the maximum lift when the chord of the wing section is extended to Lmax and the angle of attack is T, L providing short, slow, and safe takeoffs and landings at small speeds about 20 miles per hour.
[0114] The same said means give needed minimum drag when the chord of the wing section is shorter by drawn-in telescopic segments 20 B, C,D,E the chord becomes equal HDmin and angle of attack is providing minimum drag for high speed cruise flights.
[0115] The force cylinders 24 are installed and act by their coaxial sets and have their power sets 20 P. The said cylinders can work separately, independently or together, providing needed displacement and self-adjusting of moving segments, correct aerodynamic performances without affecting and disturbing of airflows, upwashes, downwashes, circulations and vortices thus preserving all the energy of air jets for effective aerodynamic lift forces.
[0116] FIGS. 8 , 9 , 10 show the hydrodynamic circuit 30 comprising said tunnel 30 A, hydrolic controlled bypass 30 B, air cooler 30 c with cooling fins 30 F, visualization 36 , meters, control 37 . A preferably axial-flow propeller pump 35 impels operative liquid 30 L inside said tunnel 30 A by motor 35 M and drive 35 D.
[0117] Said liquid 30 L is a preferably high-density solution like heavy antifreeze, salt water, bromide, other.
[0118] Said tunnel 30 A also includes:
Upper and lower waved closed loop contoured rows of smooth-connected tubular upper curved elbows 30 E and lower smooth bends 30 D, A kit of lifting winglets 32 A,B,C,D,E, placed in said elbows 30 E in series, A kit of guide-grids 33 A, B and flow-straighteners 33 S placed in said bottom bends 30 D, A static pressure control valve device 30 P with a springed piston to adjust and limit possible cavitation of operative liquid 30 L, Winglet controls 34 C, guide-grids controls 34 G. Some tunnels 30 an include adjustable pockets 33 P for some kinds of waved elbows 30 E winglets 32 and operative liquids in order to provide additional fluid-flow equalization.
[0125] Said elbows 30 E have cross section areas and curves' radii smaller than adjacent bends have in order to provide bigger velocity of operating liquid 30 L in elbow-portions of the tunnel 30 A. Said winglets 32 can be various and different including monowinglets, ladder-like, compound with smooth high-lift devices, and/or others in the same tunnel 30 A depending on design.
[0126] FIGS. 11, 12 , 13 illustrate an exemplary set-arrangement of several hydrodynamic circuits 30 into vertical walls of an exemplary bus.
[0127] FIG. 11 shows also the circuit integrated lift-forces IHL reducing the common bus-load including its own weight with engine 38 .
[0128] FIG. 13 illustrates in fragmentary section view of the tunnel's elbow 30 E, winglet 32 D, operative liquid 30 L circulating around winglet, visualization 36 , cooling fins 30 F. The hydrodynamic lift force HL generated by winglet 32 D, and result centrifugal lift force CF generated by operative liquid 30 L running in curved elbow 30 E are shown.
[0129] Operation, Effectiveness, Some Conclusions:
[0130] Aerodynamic Structure
a) The force cylinders 20 F (or solenoids, or others), driven by their power sets 20 P, move the smooth-united segments 20 B, C, D, E relatively carcass 20 a, and provide for said chord-telescopic curve-tilting wings 20 , 21 mini-gap shifts and almost gap-less displacements. These shifts lead to maximum lift AL in extended drawn-off state for short takeoffs and landings at speeds about 20 miles per hour and minimum drag at drawn-in state for high-speed cruise flights. b) Any possible interactions and interdisturbings among any various flows, jets vortices are effectively minimized. Slow takeoffs and landings, reducing of the general load by all the generated lift forces provide calm conditions to any aircraft system and real high reliability and security. c) The preservation the energy of downwash-jets and thus the self-protecting and conservation of generated lift forces in diverse flight circumstances provide economic effect, energy savings, stable flights.
[0134] Set of Hydrodynamic Circuits 30
d) The preferably, axial-flow propeller pump 35 operates as self-booster impelling the operative liquid 30 L in closed loop tunnel 30 A, working at itself, for itself, for lifting winglets 32 , and for curved elbows 30 E. The high power ratio of the pump motor 35 M is cyclically provided and effective energy preservation is reached. This is the method of my accumulative technology in which the singular pump 35 works actually in series with itself, providing high potential circulative hydrodynamic flow in closed loop tunnel 30 A with multiplied pressure ratio and limited suppressed cavitation. e) The operative liquid 30 L interacts with lifting winglets 32 and elbows 30 E in the closed loop tunnel 30 A providing integrated lift forces consisting of hydrodynamic portions generated by winglets 32 , and centrifugal portions generated by operative liquid 30 L in upper zones of elbows 30 E due to curve radii, high velocity, and high density of liquid 30 L.
[0137] FIGS. 8, 10 , 13 demonstrate how the phenomenon of an integrated lift force appears in said closed loop tunnel 30 A:
The well known hydrodynamic lift HL is mostly provided by preservation of energy of the flow which is circulating and bending the winglets 32 forcing powerful downwash-jets in waved elbows 30 E. The winglets 32 push themselves off from these jets reacting to jets which winglets 32 produced, thus generating hydrodynamic lift forces inside closed loop tunnel 30 E, The centrifugal forces CF provided by liquid 30 L moving inside curved upper zones of elbows 30 E, The integrated upwarded lift force I HL is the sum of hydrodynamic lift HL and resulting centrifugal forces CF accounting some downward centrifugal losses in smooth, low-velocity, big radii bends 30 D.
[0141] The guide-grids 33 A, B and flow-straighteners 33 S provide damping to vortices, flow equalization and correct flow directions to the adjacent winglets 32 . The initial static pressure of the operative liquid 30 L is regulated by piston 30 P in order to minimize any cavitation; the controllers 34 C and 34 G adjusting winglets 32 and guide-grids 33 G, pump drive 35 D regulating capacity of the pump 35 and thus the effective velocity of operative liquid 30 L; controlled regulating of bypass 30 B; air cooler 30 C provide needed conditions to the high potential internal flow in said self-boosting hydrodynamic technology.
[0142] A couple of basic formulae and notes.
a) Fluidynamic lift force of any aerodynamic wing 20 , 21 , and/or winglet 32 :
L w = C L · 1 2 p · u 2 · Sw ,
where C—lift coefficient, p—fluid density,
U velocity of the fluid, Sw—working area of the wing.
b) Centrifugal forces of the operative liquid 30 L in upper winglet-elbows and lower guide-grid bends:
CF = M . · U L 2 G · R γ ,
where
{dot over (M)}—instant mass of running liquid 30 L in the curved zone, U L —velocity of the liquid 30 L in the curved zones, —damping coefficient, G—gravity acceleration, R—curve radius.
c) Sum—result centrifugal force
CF =Σ CF E −Σ CF B , where Σ C F E —vector sum of elbow's centrifugal forces, Σ CF B —vector sum of bend's centrifugal forces,
d) Integrated circuit lift force is a vector sum
I HL = HL + CF , where HL is a sum of hydrodynamic winglet-lift forces
e) Hydrodynamic circuit 30 ′ power ratio PRc:
PR c = Qp · Pa H . P . P . ,
where
Qp—capacity of axial flow pump 35 , Pa—accumulated pressure of liquid 30 L in stable regime H.P.P.—power of pump motor 35 M. PR is about 7.5 depending on design.
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A Fluidynamic Lift Combined Array, Technology for flying, and/or land, and/or other motor vehicles comprises: a. an aerodynamic structure of chord-telescopic smooth-united multisegment lifting wings; and/or b. a set of hydrodynamic circuits including closed loop waved tunnels each with placed inside pump impelling operative liquid and having curved elbows with lifting winglets; and c. a method of generating high lift forces in combined fluidynamic, self-boosting, accumulative, and energy integrating and conservative technology. This proposal can provide: Short, safe, convenient for people, and appropriate for planes takeoffs and landings at speeds about 20 miles per hour. Sure overcoming any difficulties connected with heavy load for land and other vehicles. High general efficiency and profound reliability in upkeeping and thrifty technology with substantial energy conservation by additional lift generated in any tense situations.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a new intermodal railway car having the substantial benefits of a reduced profile vertically and laterally that will meet the plate B requirements of the Association of American Railroads while carrying a variety of over the highway vehicle trailers and cargo containers for railway transport. More specifically, the present invention relates to a design for intermodal railway car utilizing the substantial cost savings of sharing standard railway trucks by articulated connections between two or more or such intermodal railway cars while having the substantial structural integrity of extended side sills and stub center sills to provide a depressed center structure for the carrying of a variety of highway vehicle trailers and cargo containers for railway transport.
2. Description of the Prior Art
With the advent of interstate highway systems, over the highway vehicle travel for the transport of goods to and from the marketplace has become a substantial portion of the transport service volume from domestic manufacturers and suppliers. With the more recent energy crunch causing the cost of the fuel for the operation of such vehicular traffic to rise substantially thus increasing the cost of such mode of transportation for goods, ways have been sought to utilize the more effective means of railway transport of such goods. It has been found that an effective mix of railway and over the highway vehicles would be one where the railway is utilized to transport the goods over the long distances ending at stations whereby the over the highway vehicles can deliver the goods to the nearby areas not directly served by railway spur lines. Thus, the search for railway vehicles or railway cars that would be capable of carrying such over the highway vehicle trailers and containers began.
As early as the 1950's, such designs began to be seen in the patent literature and exemplified by U.S. Pat. Nos. 2,638,852; 2,971,478; 3,051,089; 3,102,497; 3,102,646; 3,151,575; 3,238,899; 3,223,052, 3,313,246 and 4,233,909. All of these cited references have one common theme in that the idea was to utilize over the highway vehicle trailers and containers to ship the goods but allowing them to transport over the railway system for long distances for the economies that could be derived therefrom. Of these designs, one of the major drawbacks was that in each case there was a central structural member necessary for the maintenance of the structural integrity of the units for such railway travel and as a result thereof, these units had difficulty in terms of carrying wheeled over the highway vehicle trailers due to the restrictive clearances for the railway system.
The early designs utilize a flatbed concept and generally one railway car on a set of two trucks thus the substantial burden of producing two sets of trucks for each railway car in accordance with the prior art. As it became apparent that these prior art designs had very limited capabilities in terms of the selection of various over the highway vehicle trailers and containers that they could carry and still meet the height requirements of the Association of American Railroads (referred to as AAR) for the transport on the American railway system, more recent designs began to evolve in which a depressed center portion was utilized in order to lower the overall height of such railway cars.
U.S. Pat. No. 3,357,371 was such a later development wherein the attempt was made to depress the center of the railway car to accomplish an overall lowering of the height of the container or over the highway vehicle trailers with wheels on it so as to more amply comply with the height requirements for operation on the railway system. Some of the problems associated with this design include the fact that the structure is complicated and thus more costly to construct and that the length of the lowered space for the acceptance of cargo containers or the rubber tired vehicle trailers is limited which limits the usefulness of the railway car for carrying forty-five foot trailers. Also this car in each case utilizes two railway trucks for its support and thus does not accomplish the cost savings as might be desired for a long container train.
A later design was found in U.S. Pat. No. 3,509,829 wherein a depressed center was used to provide a railway car which could contain highway vehicle trailers to be within the height requirements and did for the first time utilize two railway cars on one truck for what is generally referred to as an articulated connection. Some of the problems associated with this particular kind of car were the fact that the coupler height on this car was considerably lower than that of standard freight cars and thus if this railway car were to be put into a train containing a mixture of freight cars and these railway cars an elevator coupler mechanism was necessary to achieve equal height with the couplers of other standard cars. Also, the articulated connection of this kind of car was extremely limited in terms of the angular diposition available for cornering of the car around sharp curves that might result in certain portions of the U.S. railway track system.
Thus, these present designs have been found inadequate for many reasons but particularly for: the lack of an articulated connection which provides a coupler height equal to that of the standard car, that the depressed center portion of the car limits significantly the range of various types of containers or highway vehicle trailers that might be used on such railway cars, and the problem of carrying forty-five foot trailers
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a mechanical structure for an intermodal railway car which will meet the plate B AAR Clearance Standards when hauling as cargo a variety of types of trailers and containers including the forty-five foot trailers on intermodal railway car.
It is another object of the present invention to provide a depressed center intermodal railway car of such design as to maximize the ability of such railway car to meet the height requirements with rubber tired vehicle trailers loaded thereon in accordance with the Plate B Clearance Standards of the AAR.
It is still another object of the present invention to construct an intermodal railway car designed to minimize material and labor costs in the assembly and construction of such intermodal railway cars.
It is a further object of the present invention to reduce the profile vertically and laterally to obtain reduced wind resistance to maximize the fuel efficiency of the intermodal railway car.
It is still another object of the present invention to further reduce the economic costs of construction of such intermodal railway cars by utilizing an articulated connection between several cars upon a limited number of railway trucks thereby reducing substantially the costs of such construction.
These and other objects of the present invention, together with the advantages thereof over existing and prior art forms which will become apparent to those skilled in the art from the detailed disclosure of the present invention as set forth hereinbelow, are accomplished by the improvements herein shown, described and claimed.
It has been found that an intermodal railway car for the transportation of various types of over the highway vehicle trailers and containers can comprise: a set of two fabricated side sills; at each end thereof and connected therebetween a structural web; the structural webs terminating in a stub center sill; the stub center sill having a pivotal connection with and between a railway truck for traversing over the railway; a depressed center structure to provide support for rubber tired vehicle trailers or containers as may be placed therein; the depressed center structure being depressed in an amount sufficient to allow the intermodal railway car to meet the Plate B height restrictions when carrying a rubber tired over the highway vehicle trailer; and the depressed center structure being supported by and attached to the side sills.
It has also been found that an intermodal railway car for the transportation of rubber tired vehicle trailers or containers over the railway may comprise two or more such intermodal railway cars having a number of standard railway trucks equal to the number of intermodal railway cars plus one; articulated connections on at least one end of each intermodal railway car; the articulated connections having a stub center sill for pivotal connection to the standard railway truck; and the articulated connections also having at least one set of extension arms terminating in a side bearing connection to the standard railway truck.
The preferred embodiment of the subject intermodal railway car is shown by way of example in the accompanying drawings without attempting to show each and every of the various forms and modifications in which the invention might be embodied: the invention being measured by the appended claims, not by the details of this disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top elevation view of the intermodal railway car according to the concepts of the present invention.
FIG. 2 is a side elevation view of the intermodal car having thereon rubber tired vehicle trailers for transport over the railway system.
FIG. 3 is a side section view of the intermodal railway car having contained thereon containers for transport over the railway system.
FIG. 4 is a side section view of the intermodal railway car taken substantially along line 4--4 of FIG. 1.
FIG. 5 is a side section view of the intermodal railway car taken substantially along line 5--5 of FIG. 1.
FIG. 6 is a side section view of the intermodal railway car taken substantially along line 6--6 of FIG. 1.
FIG. 7 is a side section view of the intermodal railway car taken substantially along line 7--7 of FIG. 1.
FIG. 8 is a side section view of the intermodal railway car taken substantially along line 8--8 of FIG. 1.
FIG. 9 is a side section view of the intermodal railway car taken substantially along line 9--9 of FIG. 1.
FIG. 10 is a side section view of the intermodal railway car system taken substantially along line 10--10 of FIG. 1.
FIG. 11 is a partial longitudinal sectional view of the intermodal railway car system taken substantially along line 11--11 of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The intermodal railway car generally referred to as numeral 100 of the instant drawings as seen in those drawings represents a new type of railway car design for rail transportation of rubber tired highway vehicle trailers and containers as used for over the highway travel of packaged or containerized cargo which is becoming a significant portion of the mass cargo transportation market today. The reason for this shift toward containerization of cargo is the convenience and efficiency for handling the cargo in this fashion. A further efficiency is achieved by allowing such trailers and cargo containers to be directly unloaded from a over the highway vehicle onto a railway car for the most efficient long distance hauling to off loading at a distant site.
The intermodal railway car 100 generally is constructed of a system of fabricated side sills 102 connected at either end thereof by means of structural webs 104 generally having stub center sills 106 for direct pivotal connection to a standard railway truck 108. As can be particularly seen from FIGS. 1, 2 and 3 of the drawings, the central portion of the intermodal railway car 100 utilizes the most efficient means of reducing weight while providing structural integrity through a depressed center structure generally referred to by numeral 110. Such a depressed center structure 110 accomplishes the overall weight reduction necessary for efficient over the rail transportation of such a car while still providing significant structural integrity to the intermodal railway car 100 and the necessary capacity for handling various types of rubber tired over the highway vehicle trailers and containers. The intermodal railway car 100 has a particularly reduced profile so as to permit the carrying of the rubber tired over the highway vehicle trailers in a fashion which will meet the basic requirements of Plate B specifications of clearance set forth by the Association of American Railroads also known as the AAR.
It is significant to note that the side sills 102 of the intermodal railway car 100 are higher from the rail surface than the depressed center structure 110 of the intermodal railway car. In this fashion, the fabricated side sills 102 are nearly level with the coupling height from the rail to provide the ability for this intermodal railway car 100 to be utilized with standard railroad rolling stock of various types and mixtures for more efficient and mixed operation.
As seen in FIGS. 2 and 3, the side sills 102 have side sill steps 103 at each end thereof so that the central portion of side sills 102 may be lowered to accomodate drop frame vehicle trailers seen in FIG. 2. This is to allow room for the lifting apparatus to be extracted horizontally from the vehicle trailer during the process of lifting the vehicle trailer onto the intermodal railway car 100. As those skilled in the art will realize, if drop frame vehicle trailers are not to be accomodated, the side sills 102 could be level thus eliminating the extra construction features of the side sill steps 103.
The couplers 112 of the intermodal railway car 100 would be provided on each end of the intermodal railway car 100 if individually used or on each end of a series of intermodal railway cars 100 to provide a convenient coupling means to standard rolling stock for rail transport. The central intermodal railway cars 100 would be provided with an articulated connection 114 as seen from the drawings to obtain an additional efficiency for operation of such intermodal railway cars 100 by eliminating nearly one-half of the standard railway trucks 108 necessary to support the intermodal railway cars 100 for rail transport.
A unit train could contain an almost indefinite number of intermodal railway cars 100 for long distance rail transport of containerized cargo or rubber tired vehicle trailers. In any given intermodal railway car unit train, the number of standard railway trucks 108 would equal the number of intermodal railway cars 100 plus one (1). Thus, it can be seen that a significant savings in terms of expenditure for such standard railway trucks 108 can be achieved and at the same time reduce the rolling resistance of the intermodal railway cars 100 in such a unit train. It is expected that the more popular method of connecting the intermodal railway cars 100 would be in groupings of two or six intermodal railway cars 100 each of which may have either two articulated connections 114 or an articulated connection 114 and a standard coupler 112.
It can be seen particularly in FIG. 1 of the drawings that the depressed center structure 110 of the intermodal railway car 100 while being designed as to provide structural integrity to the overall design of the intermodal railway car 100 also provides a convenient resting zone for the tires of a rubber tired vehicle trailer. The depressed center structure 110 can be divided so as to provide the wheel resting zones toward one end of the intermodal railway car 100 and a stand conveniently to accept the coupling device of the fore end of a rubber tired vehicle trailer. As seen particularly in FIGS. 2 and 3 of the drawings, the intermodal railway car 100 having the depressed center structure 110 depressed from the height of the fabricated side sills 102 provides a convenient area for the placement of the tires of such trailers to reduce the overall height of a loaded intermodal railway car 100 so as to meet the Plate B requirements of the AAR.
As illustrated by FIGS. 2 and 3, the intermodal railway car 100 is designed to accept various combinations of containers and trailers so as to provide a fuel efficient manner for rail transport. Specifically, the intermodal railway car 100 is designed to accept reefer trailers so that the reefers will not be the cause of any clearance problems during transit. Container brackets 116 are appropriately placed in the intermodal railway car 100 to accept the corners of containers to achieve stable loading of the containers on the intermodal railway cars 100 for rail shipment. FIG. 3 shows the use of container brackets 116 on top of the side sills 102 to accept the long containers where this arrangement will meet the height requirements of the railway being traversed. As further seen in FIG. 8 of the drawings, container brackets 116 may also be positioned in the depressed center structure 110 to accomodate shorter containers. This of course lowers the overall height to allow compliance with more stringent railway height requirements.
The container brackets 116 may be made of any convenient design, many different designs of which will occur to those skilled in the art. The main requirements for the container brackets 116 are that they accept the corners of the container and hold the horizontal position of the container secure and stable during transit.
It will also be noticed that stands 117 are provided for suitable stable resting positions for the front end coupler of rubber tired vehicle trailers. As with container brackets 116, they may be of any convenient design which will provide the required stable support for the rubber tired vehicle trailer front coupler for railway transport.
Referring to FIG. 1 of the drawings, it can been seen that the sectional drawings 4 through 11 are keyed as to provide reference from FIG. 1 for those skilled in the art as to the fabrication of the intermodal railway car 100 in the various sections as seen. Particularly FIG. 4 shows the basic construction of the standard coupler 112 end of intermodal railway car 100. The standard coupler 112 end of intermodal railway car 100 has a structural web 104 as shown in FIG. 4 of the drawings interconnected between and to the fabricated side sills 102. The arrangement includes a top plate 118 resting on top of the fabricated side sills 102 and a web plate 119. The web plate 119 could be of standard AAR box type construction or of a single plate type construction as will occur to those skilled in the art.
The fabricated side sills 102 are constructed by permanently joining a side sill angle 120 to a side sill channel 122 by means of side struts 124 on the outward side of the intermodal railway car 100 fabricated side sills 102. On the inside portion of the fabricated side sills 102 is a flat plate 126 which is permanently connected to the structural webs 104 as seen in FIG. 4 as well as to the side sill angle 120 and the side sill channel 122. Since the side struts 124 are reinforcing members for the side sills 102 it is anticipated that those skilled in the art will be readily able to substitute many structural shapes capable of performing this reinforcement function. As shown in FIG. 4 the side struts 124 are made of formed channel stock, however, flat plate, apertured flat plate, rectangular tubing or round tubing would also perform the required function.
The side sills 102 as shown in FIG. 4 are slightly lower than the top edge of the structural web 104 which in this case causes the need for an offset bend in top plate 118. If desired however, the side sills 102 may be made flush with the top of the structural web 104 to allow the use of a flat top plate 118 or a filler plate not shown which may be added on top of the side sill angle 120 to bring the side sill 102 up flush with the top of the structural web 104.
The fabricated side sills 102 are also structurally bolstered in their permanent attachment to the structural webs 104 by means of bottom gusset plates 128 which are connected between the bottom plate 130 of the structural webs 104 and flat plate 126 of the side sills 102. Near the center of the structural web 104 can be found the stub center sill 106 which in the case of FIG. 4 is directly connected to the standard coupler 112. The stub center sill 106 is tied to the structural web 104 as a component thereof by means of a tie plate 132 and the bottom plate 130 of the structural web 104. The stub center sill 106 is also connected by permanent means to the top plates 118 of the structural web 104. The stub center sills 106 may be constructed according to any of the conventional designs such as two Z members or flat plates.
The structural web 104 may be also reinforced and strengthened by means of placing web supports 134 in various positions along the bottom plates 130 of the structural web 104 and also along the top plate 118 which is not shown in FIG. 4. Furthermore, the larger more open area of the structural webs 104 can be strengthened and reinforced by means of web reinforcing rings 136 as seen in FIG. 4 so as to provide a high degree of structural integrity to the overall structural web 104 construction.
Furthermore as seen in FIG. 4 of the drawings at the intersection of the stub center sill 106 and the top plate 118, a stress relief aperture is left in each corner to prevent stress from building up in this region. Such stresses could result in premature failure of some of the components of the structural web 104 which would be detrimental to the structural integrity of the intermodal railway car 100.
The structural web 104 as seen in FIG. 4 of the drawings is connected to a standard railway truck 108 as shown by means of a pivotal connecter pin 138 to provide for pivotal movement of the intermodal railway car 100 upon the standard railway truck 108 for curve negotiating ability of the intermodal railway car 100 in a fashion similar to that of a standard railway rolling stock.
In the fore end of the intermodal railway car 100, the depressed center structure 110 takes the form of a structural stringer 140 connected in a permanent fashion by means of cross ties 142 to the fabricated side sills 102 to provide a structural integrity to the fore end of the intermodal railway car 100. The composition of the structural stringer 140 includes a stiffener structural shape such as hats 144 having a structural stringer base plate 146 connected to hats 144 and a structural stringer top plate 148 also connected to hats 144. The structural stringer base plates 146 are connected to the cross ties 142 and in such a way that the structural stringer base plate 146 becomes the bottom plate of the cross tie 142 as it connects to the fabricated side sills 102. In this way, the fore end of the intermodal railway car 100 presents a depressed center portion structurally connected to the fabricated side sills 102.
The structural stringer 140 may stretch the entire length of the intermodal railway car 100 to provide a lighter weight embodiment for container handling. Such alternative embodiments would be very useful in meeting the New York City area plate restrictions which are more severe than the plate "B" restrictions.
Furthermore, the structural stringer 140 may be connected to a central connector 149 to provide the illustrated embodiment to carry a variety of containers and rubber tired vehicle trailers. As seen in FIG. 1, the central connector 149 may be in approximately the longitudinal center of the intermodal railway car 100 but the central connector 149 may be placed anywhere the builder desires to achieve the capability to carry the various types of containers and trailers the intermodal railway car 100 is being constructed to carry.
FIG. 6 of the drawings shows the depressed center structure 110 at the central connector 149 in the intermodal railway car 100 whereby the fore end structural stringer 140 is connected to a structural cross tie 150 directly by hats 144, the structural stringer base plate 146 and structural stringer top plate 148 to the end tubular tire rest stringers 152 found in the aft portion of the intermodal railway car 100. The central connector 149 is a transition member from the structural stringer 140 to the tubular tire rest stringer 152 in a manner to assure the overall strength of the depressed center structure 110.
FIG. 7 of the drawings shows the aft end of the intermodal railway car 100 particularly showing the depressed center structure 110 as constructed of a stiffener structural shape such as tubular tire rest stringers 152 having attached to the top portion thereof surface sheets 154 upon which the tires of a rubber tired over the highway vehicle trailer can rest in a convenient fashion. Also as found in the aft end of the intermodal railway car 100, the tubular tire rest stringer members 152 are connected to cross ties 150 in a fashion similar to that of the cross ties 142 in the fore end of the intermodal railway car 100. In this situation however, the cross ties are composed of cross tie side channels 156 which are in turn connected to cross tie side supports 158 which are connected in turn to the fabricated side sills 102. The tubular tire rest stringer 152 surface sheets 154 may be constructed of solid sheet material, apertured sheet material, expanded metal mesh material or any of these materials in combination with a structural shape for stiffening of the surface sheets 154. The main concept calls for the surface sheets 154 to be tied to the tubular tire rest stringer 152 in a way that will provide longitudinal stiffening to the intermodal railway car 100.
Also as seen in FIG. 7, a tire guide 160 may be conveniently placed along the inside portion of the fabricated side sills 102 to keep the rubber tired over the highway vehicle trailers more or less centered in the intermodal railway car 100 during railway transit.
FIG. 8 of the drawings shows the manner in which the tubular tire rest stringers 152 are connected to a structural cross tie 150 near the aft end of the intermodal railway car 100 as seen facing the articulated connection 114 end of the intermodal railway car 100. Contained in the corners of the depressed center structure 110 are container brackets 116 which may be constructed in any of a number of standard configurations to handle the corners of a container as will be readily known by those skilled in the art.
FIGS. 9 and 10 of the drawings illustrate from two directions sectional views of an articulated connection 114 for the intermodal railway car 100 so as to provide the substantial economies involved in the production of intermodal railway cars 100 with standard railway trucks 108 in a number equal to the number of intermodal railway cars 100 plus one. The articulated connection 114 joint member may be of conventional design as amply illustrated by U.S. Pat. No. 3,646,604. This cuts the cost of standard railway trucks 108 by a factor of at least 25% when only two intermodal railway cars 100 are interconnected permanently and by a factor of up to 50% when a large number of such intermodal railway cars 100 are so connected by articulated connections 114.
It can be seen in this case that the structural webs 104 are similar to those seen in FIG. 4 with the major exception being that the stub center sills 106 are extended to a greater height by means of two stub center sill side fillers 162 and one stub center sill top filler plate 164 to provide the adequate height necessary for the extension arms 166. As can be seen by looking jointly at FIGS. 9 and 10, the articulated connection 114 utilizes the concept of a bifurcated side bearing system 168 as shown. Each individual intermodal railway car 100 can be supported by two side bearings on the standard railway truck 108 in a fashion similar to that utilized for a standard railway car. Thus, the extension arms 166 will extend from each intermodal railway car 100 to allow each extension arm 166 to pass by the extension arm 166 from the other opposing intermodal railway car 100 extension arm 166.
The extension arms 166 are connected integrally to the intermodal railway car 100 at top plates 118 which form the top section of the structural webs 104. The extension arms 166 are fabricated structural members of sufficient integrity to support the side cage bearing in a normal manner. As particularly seen in FIG. 11 which shows a side section view of the extension arms 166, it can be seen that this particular embodiment employs the use of an I-shaped beam 170 integrally connected to the top plate 118 and to the bottom plate 130 of the structural web 104. Reinforcement is provided by means of gusset plates 172. The bottom plate 130 of structural web 104 is extended into the central portion of the I-shaped beam 170 so as to provide additional strength in the area of the extension arm 166 forward most reach. Across the end portion of the I-shaped beam is found a cap plate 174 on each extension arm with front filler plates 176 and bottom filler plates 178 to provide the required surface area for the resting zone upon the side bearing 180. At a point approximately centered over the side bearing 180 is a further vertical tie plate 182 between the cap plates 174 and the bottom filler plates 178 and also permanently connected to the I-shaped beam 170. This adds vertical stiffening to the extension arms 166 at the point of highest vertical strain on the extension arms 166.
The side bearings 180 may be of conventional design and manufacture such as the Stucki side bearing cages utilized on most 70 ton standard railway trucks 108. With all of the extension arms 166 in place, you will have four independent Stucki bearings 180 supporting four extension arms 166 in a given articulated connection 114 which will generally have an angular disposition limit of approximately 10% relative to the horizontal. This is particularly helpful to isolate the mechanical motion of the various intermodal railway cars 100 to prevent rocking of such cars during railway transit which has a tendency to introduce an angular moment to the standard railway truck 100.
The angular moment forces of the rocking motion can cause premature wear of components of the standard railway truck 108 if there is any twisting of the standard railway truck 108 itself. The premature wear of standard railway truck 108 components has been solved by the present invention by maintaining the pivot point of the rocking motion angular rotational moment forces for both intermodal railway cars 100 supported by the one standard railway truck 108 on the same axis. If the standard railway truck 108 were bisected along a line parallel to the axles of the wheels and perpendicular to the rails of track, the result would be the X axis shown in FIGS. 2, 3 and 11 on which each side bearing 180 is centered. This side by side centered arrangement or the bifurcated side bearing system 168 keeps the rocking motion of the intermodal railway car 100 from twisting the standard railway truck 108 by absorbing these angular rotational movement forces on the same axis. Thus, this arrangement significantly reduces premature wear problems associated with the standard railway truck 108 components.
The tapering of the I-shaped beam 170 is particularly useful to allow tucking of the extension arms 166 upon bending of the intermodal railway cars 100 in the horizontal angular position. Also the rearward portion of bottom filler plates 178 are tapered down toward the gusset plates 172 to allow tucking of the extension arms 166. The web construction of the extension arms 166 stretches the longitudinal forces which are applied to the intermodal railway cars 100 during such transit. To provide for the uniformity of the angular moment exerted on the extension arms 166 of each intermodal railway car 100, each intermodal railway car 100 will either have two inside extension arms 166 or two outside extension arms 166 as amply seen from the combination of FIGS. 9, 10 and 1. Structured in this fashion, each intermodal railway car 100 will have an independent and equal distant suspension system that will provide for equal tracking of the cars in a unit train consisting of many of such intermodal railway cars 100 having articulated connections 114 between each car 100. Additionally, it is advantageous to have the two outside extension arms 166 on the end of the intermodal railway car 100 containing the tire rest stringers 152 to maximize the stability of the intermodal railway car 100.
Thus, it should be apparent from the foregoing description of the preferred embodiment, that the subject intermodal railway car 100 as herein shown and described accomplishes the objects of the invention and has solved many problems attendent to such intermodal railway cars 100 and their use in the American railroad system to provide intermodal transport of rubber tired vehicle trailers and containers in a fashion which will meet the Plate B requirements of the AAR.
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Disclosed is an intermodal railway car 100 capable of carrying a number of different designs of highway vehicle trailers or cargo containers used to ship goods over such distances as will make railway transportation of such trailers or containers economically advantageous over other forms of transporting such goods to the marketplace. The intermodal railway car 100 is designed with a reduced profile vertically and laterally to allow clearance of Association of American Railroads clearance diagram-plae "B". Furthermore, the car is designed to minimize cost in terms of the use of standard railway trucks 108 to support more than one intermodal railway car 100 thereby reducing the number of trucks 108 and the expense thereof for the construction of such intermodal railway cars 100 by the factor of the number of intermodal railway cars 100 minus one. The intermodal railway car 100 incorporates an articulated connection 114 that can be arranged on either end of the intermodal railway car 100 so as to permit the joining of such intermodal railway cars 100 into groups of two or more so as to significantly reduce the overall production costs thereof while obtaining and maintaining the substantial benefits of versatility for the carrying of highway vehicle trailers or containers.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates generally to cord locks and holders, for example, for use with luggage, baggage, baggage carriers, etc. More particularly, the invention relates to a new cord lock which can be preloaded for ready use and which can subsequently be actuated in an easy manner.
2. Description of Related Art
Cord locks are known in the art for gripping and retaining cord, for example, an elastic shock cord, under tension. Such devices typically include a pair of telescoping members which have apertures therethrough. One telescoping member is biased with respect to the other, so that their respective apertures are not aligned. In order to use the cord lock, it is necessary to load it by squeezing the two telescoping members together so that their respective apertures are aligned. The user must continue to apply pressure to hold the two members together in this aligned state while simultaneously threading the cord through the apertures. Once the cord is threaded, the user may release the pressure which is exerted on the two members. Because the two members are biased so that their apertures are misaligned, they will pinch the cord which has been threaded therethrough so as to retain the cord in a fixed position.
Although this design has proven to be effective in holding and locking a cord, such as an elastic shock cord, one principal disadvantage is that the user must continue to exert pressure to align the apertures of the two telescoping members while simultaneously threading the cord through the apertures. Because the biasing force which is necessary to sufficiently grip the cord is relatively strong, a relatively large amount of finger pressure must be applied to align the apertures. Thus, it can be cumbersome to simultaneously thread the cord through the apertures while maintaining the apertures aligned (i.e., loading the device).
Another shortcoming of the prior art is that there is a risk that the lock can be inadvertently disengaged by someone squeezing the two telescoping members together, thereby relieving the tension on the cord and allowing the cord to slip. To minimize the risk of accidental disengagement, the prior art employs a very strong biasing means which requires a great amount of force to oppose. However, as discussed above, this makes the lock all the more difficult to load prior to threading of the cord.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the invention to provide a cord lock which can be preloaded with its apertures aligned prior to use so that the user can easily thread a cord therethrough without the necessity of simultaneously applying pressure to the lock.
It is a further object of the invention to provide such a lock whereby the preload can be easily released once the cord has been threaded therethrough.
It is another object of the invention to provide a cord lock which cannot be accidentally disengaged during use.
These and other objects of the invention are attained by the preloadable cord holder/lock of the present invention which includes a pair of telescoping members, each having an aperture defined therein, where the telescoping members can be preloaded to a position where the apertures are in an aligned, or at least partially aligned, state, and retained in this preloaded position without the need to apply pressure to the device. A spring or other biasing means is provided for urging the apertures out of alignment, however, it is ineffective to cause such misalignment when the device is in the preloaded state.
The preloaded condition is retained by a mechanism which includes a pair of engagement members provided on the inner telescoping member which cooperate with a corresponding set of engagement members provided on the inner surface of the outer telescoping member. The respective engagement members have cooperating inclined, preferably parallel, surfaces which permit one-way sliding travel of the inner telescoping member with respect to the outer telescoping member, namely, travel in the direction which brings the apertures of the telescoping members into alignment. The respective engagement members further include cooperating surfaces which preclude movement of the telescoping members relative to each other once the apertures are in an aligned condition. In the preloaded state, the cord is fed through the aligned, or semi-aligned, apertures.
The outer telescoping member includes a pair of tabs on opposite sides. Depression of the tabs inward forces the engagement members of the inner telescoping member inward and out of engagement with the engagement members of the outer telescoping member. This allows the inner and outer telescoping members to slide apart under the action of the biasing means. Of course, this movement is restricted by the cord which has been threaded through the aligned apertures. The force which is exerted by the biasing means against the cord will now cause the telescoping members to pinch and retain the cord in a fixed position under the force of friction.
Preferably, the inner and outer telescoping members are configured so that once the cord is threaded through the device and the retaining means is disengaged so as to lock the cord in place, the inner telescoping member will not project out of the outer telescoping member. This will prevent the user from accidentally preloading the device and unlocking the cord.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an enlarged perspective view of the cord lock of the invention, having a shock cord threaded therethrough, in a locked state.
FIG. 2 is a partial cross-sectional view of the cord lock in an unloaded condition.
FIG. 3 is a partial cross-sectional view of a cord lock in a preloaded condition.
FIG. 4 is a side-view of the cord lock illustrated in FIG. 3.
FIG. 5 is an isolated view of the engagement members of the cord lock of the invention in the preloaded condition.
FIG. 6 is an isolated view of the engagement members of the cord lock in an unloaded condition.
FIG. 7 is an isolated view of a tab and an engagement member on an inner surface of the outer telescoping member.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIGS. 1 and 2, the cord lock generally illustrated at 1 includes an inner telescoping member 2 which is slidably received in an outer telescoping member 3. The telescoping members 2, 3 define an aperture 4, 5, respectively, therein. The inner and outer telescoping members are coupled by a biasing means such as a spring 6. The biasing means 6 biases the inner telescoping member 2 in a direction such that the respective apertures 4, 5 of the telescoping members are out of alignment or misaligned as illustrated in FIG. 2. The condition referred to in FIG. 2 shall be referred to as an unloaded condition. Any overlap in apertures 4 and 5 in this unloaded condition (preferably, the apertures are completely out of alignment so that no overlap is present) should be considerably smaller than the diameter of the cord 21 (see FIGS. 1 and 2) which is to be pinched between the apertures using the lock.
As illustrated in FIG. 2, the biasing means may be a spring 6, which receives cylindrical fixing cylinders 7, 8, belonging to the inner and outer telescoping members, respectively, in opposite ends of the spring. The fixing members 7, 8 function to couple the telescoping members to the spring and to restrict unwanted bending or kinking of the spring during compression when the cord lock is preloaded.
The cord lock 1 of the invention includes a retaining means for holding the lock in a preloaded condition where the apertures 4, 5 are in substantial alignment to an extent which is sufficient to define an overlap area which is large enough to receive cord 21 therethrough. In the preferred embodiment, the retaining means includes a pair of arms 9, belonging to the inner telescoping member and projecting downward. Each arm 9 includes an outwardly projecting wing 10. Each wing 10 includes at least a first, inclined surface 11, and a second surface 12 which is normal to the arm 9 to which it belongs. A third surface 20, normal to the second surface 12 and obtusely angled to the first surface 11 may connect the first and second surfaces. The arms 9 are elongated to permit some flexing in lateral directions toward the center of the outer telescoping member 3.
The outer telescoping member 3 is formed with a pair of opposing tabs 13. The tabs are cut from the wall of the outer telescoping member so as to be flexible and movable relative to the outer telescoping member (see FIG. 4). Each tab may have a projection 14, projecting toward the interior of the outer telescoping member. The projection 14 includes a first flat surface 15, whose function will be described hereinafter (see FIG. 6).
The inside wall 16 of the outer telescoping member has two sets of opposed engagement projections 17 on opposite sides of the lock, whose cross-section is that of a right triangle, as illustrated in FIGS. 3, 5 and 6. As illustrated in FIG. 7, each set of the opposed engagement projections may consist of a pair of individual projections 17 disposed on opposite sides of the cut-out tabs 13. Each projection 17 includes a first, inclined surface 18 which forms an acute angle with a second surface 19, the second surface 19 being substantially normal to the inner surface 16 of the outer telescoping member. Preferably, the first, inclined surface 18 of each engagement projection 17 is approximately parallel to the first, inclined surface 11 of each corresponding wing 10; and the second surface 19 of each projection 17 is approximately parallel to the second surface 12 of each wing 10, as illustrated in FIG. 2.
As illustrated in FIG. 2, when the device 1 is in an unloaded condition, the apertures 4, 5 of the inner and outer telescoping members will be substantially or completely out of alignment. The spring 6 will urge the telescoping members into this condition. In order to preload the device, the inner and outer telescoping members 2, 3 are forced together to compress the spring 6. This drives the arms 9 and wings 10 of the inner telescoping member 2 downward toward the opposed engagement projections 17 of the outer telescoping member 3. The first, inclined surface 11 of each wing 10 will engage the first, inclined surface 18 of each projection 17. The surfaces are inclined so that the wings may easily slide past the engagement projections 17. It will be appreciated that the arms 9 are flexible enough to be urged laterally toward the center of the device as the wings 10 traverse each projection 17. Once the third surface 20 of each wing has passed by the first, inclined surface 18 of each projection 17, the arms 9 of the inner telescoping member 2 will be free to flex laterally outward in the direction toward the inner wall 16 of the outer telescoping member 3, thereby snapping the wings 10 underneath the second surface 19 of the projections 17 (see FIGS. 3 and 5). Although the compressed spring 6 continues to bias the inner telescoping member 2 away from the outer telescoping member 3, the second surface 19 of projections 17 will engage the second surface 12 of the wings 10 to prevent the wings from moving back over the projection 17. This condition shall be referred to as the preloaded condition. It should be appreciated that the length of the arms 9 and the position of the projections 17 relative to that of the wings 10 is such that the apertures 4, 5 will be aligned in this preloaded condition to an extent which is sufficient to define an area of aperture overlap which is large enough to accommodate a cord to be locked by the device.
It is in this preloaded condition that the user may easily thread a cord 21, such as an elastic shock cord, through the apertures. Once the cord 21 is in the desired position, it can be locked in place by pushing inward on the tabs 13 (i.e,, squeezing the tabs between two fingers toward the center of the device). The inward lateral movement of the projection 14 of each tab 13 will engage flat surface 15 with third surface 20 and force each wing 10 inward until each wing has cleared the second surface 19 of projection 17. The spring 6 will then force the telescoping members 2, 3 apart, thereby clamping the shock cord in the apertures which are continually biased out of alignment. This state will be referred to as the locked condition or cord locking position.
In this locked condition, preferably the top of the inner telescoping member 2 does not project out of the top of the outer telescoping member 3. In this way, a person cannot accidentally unlock the device by pushing downward on the inner telescoping member 2 to cause preloading. Preferably, the top of the inner telescoping member 2 is substantially flush with the top of the outer telescoping member 3 or is slightly receded therein in the locked condition as illustrated in FIG. 1. This arrangement prevents accidental unlocking of the device, however, it permits deliberate unlocking of the device as a person would be able to force a fingernail or a pencil or the like, into the outer telescoping member to push the inner telescoping member 2 downward, back to the preloaded position where the cord will be free to slide out of the aligned apertures. The cord lock 1 may then be repositioned to a new desired location and relocked by simply pushing inward on the tabs 13.
The top of the outer telescoping member 3 may have a rim 22 (see FIG. 2) which cooperates with a flange 23 (see FIG. 3) of the inner telescoping member 2 to restrict the movement of the inner telescoping member relative to the outer telescoping member so as to prevent the two members from becoming completely separated. For this purpose, the spring 6 may also be fixedly attached at each of its ends to the fixing members 7, 8. In order to restrict movement of the inner telescoping member relative to the outer telescoping member in the opposite direction, the outer telescoping member may be provided with stop members 24 on the inside surface of its bottom wall 25. The stop members 24 will engage a fourth surface 26 of the wings 10 to prevent further downward movement of the inner telescoping member. Alternatively, tabs 13 and projections 17 may be positioned such that the apertures 4, 5 are aligned when the fourth surface 26 contacts the inner surface of the bottom wall 25 so that no stop members are necessary.
The cord lock of the invention is preferably constructed of a resilient-flexible plastic material to allow for the flexing and snapping cooperation between the arms 9 and the tabs 13. The cord lock is easily molded using conventional molding techniques well known in the art.
In the foregoing specification, the invention has been described with reference to specific exemplary embodiments thereof. It will, however, be evident that various modifications and changes may be made thereunto without departing from the broader spirit and scope of the invention as set forth in the appended claims. The specification and drawings are accordingly to be regarded in an illustrative rather than a restrictive sense.
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A preloadable cord lock for gripping a cord, such as an elastic shock cord, includes a pair of telescoping members having apertures defined therethrough. The telescoping members are biased so that their respective apertures are not aligned. The lock can be preloaded to a condition where the apertures are aligned for feeding a cord through the apertures. The preloading mechanism may then be disengaged which will cause the telescoping members to be urged to a position where their apertures are not aligned by the bias of the device, thereby pinching and locking the cord in place.
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FIELD OF THE INVENTION
This invention relates to an orthopedic drill guide, specifically an orthopedic drill guide having a hollow curved aiming device for insertion of a flexible drill bit there through.
BACKGROUND
Typically, tissue repair to the shoulder area, such as reattaching torn rotator cuff tendons to bone, is done through open surgery. However, open surgery introduces potential problems with the trauma associated with the large area of skin, muscle and tissue which must be incised to perform such surgery.
Arthroscopic surgery has the advantages of making a small incision and therefore reducing the risk of infection, blood loss and the like which is sometimes the result of open surgery. However, arthroscopic repair of the rotator cuff through bone tunnels has not been performed, a result of, among other things, lacking the necessary instruments. For example, in attaching the rotator cuff to the humerus by suturing the tendon to the bone by passing the suture through a hole drilled through the proximal portion of the humerus, specific problems arise. Just distal to the bone tunnel site lies the axillary nerve, a major nerve which innervates the deltoid muscle. If the axillary nerve is damaged, movement of the shoulder may be impaired. Proximal to the humerus is the acromion. Thus, the location at which the tunnel is to be drilled is effectively "boxed in". This prevents the use of straight pins to bore the hole.
Applicant has provided an instrument which allows drilling a straight hole through bone in an area bordered by obstacles. Applicant has provided a device in which straight holes can be drilled in bones through the use of a flexible pin, such as a Nitinol pin, used in conjunction with a curved, tubular aiming device, and a curved tubular receiving device. Moreover, since the acromion may be different lengths in different individuals, there is needed some adjustability to the drilling device. Orthopedic drill guide devices are known in the art. For example U.S. Pat. No. 4,945,904 (Bolton, et al 1990) discloses an orthopedic drill guide device used to locate and guide the drilling of holes in bones for the purpose of implanting tissue repair devices. Specifically, the Bolton drill guide device is designed to locate, align and guide the drilling of a tibial through-hole and then to locate, align and guide the drilling of the femoral through-hole with respect the previous drilled tibial through hole. The Bolton device would be incapable of use arthroscopically for shoulder work such as reattaching torn rotator cuffs. The Bolton device, like other prior art devices, provides a device wherein the longitudinal axis of the drill guide aiming device is designed to align with the longitudinal axis of the hole which is intended to be drilled. Applicant, on the other hand, cannot use such a device because of the proximity of the axillary nerve and the acromion to the drill site.
Another prior art device for use as a drill guide is disclosed in U.S. Pat. No. 5,112,337 (Paulos, et al 1992). The Paulos patent discloses another straight tubular drill guide aiming device for alignment with the longitudinal axis of the tunnel to be drilled. Specifically, the Paulos drill guide is designed for drilling a tunnel in the tibia for anterior cruciate ligament reconstruction. The drill guide aiming device is used in conjunction with a target hook having a point for engaging and determining the exit point of the tunnel. The shortcomings of this device with respect to arthroscopic shoulder surgery are the same as Bolton, both require the use of a straight tubular aiming device with longitudinal axis coincident with the longitudinal axis of the tunnel to be drilled.
Thus, applicant's device provides for the use of a curved aiming device, tubular for receipt of a flexible pin, for alignment adjacent an entry point and drilling a straight tunnel through proximal end of the humerus, while avoiding exposure of the axillary nerve to the instrument. Applicant also provides for a curved tubular receiving device which avoids interference between the pin and the acromion. Thus, applicant provides an orthopedic drill guide device for use in drilling a straight tunnel through bone where obstructions prevent the use of straight drill aiming and receiving devices.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevational view of drill guide 10 with aiming and recovery means in place against proximal end of the humerus illustrating generally the position of the device in use.
FIG. 1A is a top elevational view of the aiming device of applicant's invention attached to the frame.
FIGS. 2, 2A and 2B are elevational views illustrating details of the aiming device of applicant's invention.
FIGS. 3, 3A, 3B, 3C and 3D are various elevational views illustrating details of the receiving device of applicant's invention showing tube (32) detached from attachment means (33) (FIG. 3.)
FIG. 4 is an elevational view of the frame of applicant's present invention with aiming device and receiving device removed therefrom.
FIG. 4A is an elevational cross sectional cutaway view through the adjustment means of the drill guide and a partial cross sectional view through the release means of the drill guide with receiving device (16) in place.
FIG. 5 is a side elevational view of an alternate preferred embodiment of the drill guide.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGS. 1-4A illustrate various views showing the main components of applicant's drill guide (10). Drill guide (10) is seen to comprise a curved frame (12) having a rectangular cross section (see also FIG. 4A) and a constant radius of curvature. Attached to one end of frame (12) is aiming device (14). Slidably attached to frame (12) is receiving device (16), movable with respect to aiming device (14).
Aiming device (14) is comprised of hollow tube (18) having a removed curvedend (20). Tube (18) is dimensioned sufficiently to enable the passage of pin (26) therethrough. Pin (26) is designed to enter tube (18) at straightend (24) through straight end opening (25). Pin (26) passes through straight portion (22) of tube (18), through curved end (20) and out pin opening (21) (see also FIGS. 2 and 2A). Pin (26) is typically Nitinol and has a loop (28) at one end thereof for passing a suture therethrough. Tip (30) is located at the other end of pin (26) for puncturing the cortex of the humerus and creating the tunnel through the bone (see FIG. 1). Aiming device (14) is mounted to frame (12) by mounting means (27) as more specifically set forth in detail below.
It can be seen then that aiming device (14) is capable of receiving pin (26) that is flexible enough so it can change direction from straight portion (22) at curved end (20) which curved end is placed adjacent to thecortex of proximal humerus as more specifically set forth below. This change in direction occurs as pin (26) is urged through tube (18) and tip (30) strikes the walls of bore (23) as tip approaches and passes through curved end (20). Receiving device (16) is designed to capture tip (30) of pin (26) as it exits the cortex of the proximal humerus and before it reaches the acromion. This is done by providing receiving device (16) witha tube (32) of dimension similar to that of tube (18) of aiming device (14). Tube (32) of receiving device (16) has straight portion (34) and a curved end (36). Curved end (36) captures pin (26) as it exits the cortex of the humerus and redirects flexible pin (26) along straight portion (34)thereof.
As can be seen in FIG. 1 pin (26) is capable of extending through bore (38)and out straight end (40) through straight end opening (42). That is, pin (26) changes direction between the axis of the hole drilled in the humerus(see FIG. 1) and the axis of straight portion (34). This change of direction occurs at curved end (36) as pin (26) enters pin opening (44) and engages the walls of bore (38). Such a change in direction is necessary to prevent interference between pin (26) and the acromion.
As seen in FIG. 1 attachment means (33) provides means for adjustably attaching receiving device (16) to frame (12) in a manner more specifically set forth below and with reference to FIGS. 3-4A. Release means (46) allows receiving device (16) to be removed from adjustment means (48). Adjustment means (48) allows receiving device (16) to be adjustably set at a variety of angles with respect to aiming device (14). This adjustment is provided to accommodate different size individuals. Forexample, with some individuals, the acromion may not reach as far as illustrated in FIG. 1 or may reach further distally than illustrated in FIG. 1 and thus require a more narrow angle between aiming device (14) andreceiving device (16).
Turning now to details of aiming device (14) and with reference to FIGS. 2-2B, it is noted that aiming device (14) is comprised of rectangular standoff (50) which functions to set tube (18) in a plane outside of but parallel to the plane created by curved frame (12). This offset matches a similar offset of receiving device (16) and is found to be more convenientto manufacturer and use as compared to having no offset. At the distal end of standoff (50) is located shaft (52) which is cylindrical in nature having a longitude axis parallel to that of straight portion (22) of tube (18). Shaft (52) is attached to standoff by tabular ridge (54). The dimensions of shaft (52) and ridge (54) as well as stop (56) are designed for slidable receipt into mounting means (27) as more particularly set forth below with reference to FIGS. 4 and 1A.
FIGS. 2-2B help illustrate the design of curved end (20) of tube (18). Morespecifically, it is seen with reference to FIG. 2A that curved end (20) haspin opening (21) that is beveled with respect to axis (A) (see FIG. 1). Axis (A) is the axis of pin (26) as it emerges from pin opening (21) and curved end (20) and also defines the axis of the tunnel or hole drilled inthe humerus as illustrated in FIG. 1. This beveled tip of curved end (20) is provided to keep pin (26) in contact as long as possible with the wallsof pin opening (21) until contact between tip (30 ) of pin (26 ) and the cortex of the bone to be drilled. That is, as tip (30) of pin (26), which is rotating at a high speed as it merges from pin opening (21), strikes the cortex of the humerus it will attempt to "ride up" to the top of pin opening (21) as viewed in FIG. 2. For as true an axis as possible, therefore, opening (21) has walls beveled to maintain curved end (20) in contact with pin (26) and minimize the free space between curved end (20) and the cortex of the bone to be drilled.
Turning now to FIGS. 3-3D and the details of receiving device (16), it is seen that receiving device (16) has walls defining a groove (58) in the outer walls of straight portion (34) thereof. A stop collar (60) is located at the terminus of straight end (40) of tube (32) adjacent straight end opening (42). Receiving device (16) is comprised of tube (32)engageable with a cylindrical mounting member (62). The cylindrical mounting member (62) has a standoff arm (64) to hold tube (32) adjacent the plane of frame (12), the same distance therefrom that standoff (50) provides for aiming device (14). Standoff arm (64) is attached to cylindrical mounting member (62), the latter having a bore (66) therethrough for receipt of tube (32) therethrough. A thumbscrew (68) is threaded through cylindrical member (62) which has bore (66) just slightlylarger than diameter of tube (32) such that groove (58) faces the removed end of thumbscrew (68). This allows tube (32) of receiving device (16) to be adjustably set with different lengths with respect to the distance between pin opening (44) of curve (36) and frame (12). This is effected bysliding tube (32) through bore (66) until the required length is reached and then tightening thumbscrew (68) against groove (58). This adjustment is provided to accommodate typical anatomical differences between various individuals.
At removed end of standoff arm (64) opposite cylindrical mounting member (62) is found insert stub (70) with locking collar (72) at one end thereof. Insert stub (70) is designed for receipt into adjustment means (48) at release means (46) as more specifically set forth below with reference to FIGS. 3, 3A and 4. Insert stub (70) is generally cylindrical with the exception of having a portion of its circumference defining flat side (74) as seen in FIGS. 3A and 3C. Flat side (74) will engage release means (46) to maintain a fixed angular relationship between standoff arm (64) and frame (12).
FIG. 3A also illustrates walls (76) of pin opening (44) of receiving device(16). As seen in FIG. 3A of walls (76) will be generally parallel to the plane of the longitudinal and axis of straight portion (34) tube (32). This provides for a sufficiently large, oval shaped, pin opening (44) and therefore ease of receipt of, and a greater likelihood of capturing, pin (26) as tip (30) emerges from the cortex of the tunnel drilled in the bone. Reference to FIG. 1 also illustrates the passage of pin (26) throughthe tunnel as it is captured by receiving device (16) and redirected by interference between tip (30) and walls of bore (38) to align with axis ofstraight portion (34) of tube (32). The net effect of providing curved end (20) to aiming device (14) and curved end (36) to receiving device (16) isto, when used in conjunction with flexible rotating pin (26), provide for ameans of drilling a straight hole through a bone in a confined space such as that illustrated in FIG. 1.
Turning now to FIG. 4 and with reference to all of the preceding figures the structure used as drill guide (10) can be appreciated. Specifically, FIG. 4 illustrates curved frame (12) having generally rectangular body (78) with indicia (84) on the walls thereof. The indicia are markings denoting the interior angle between the axes of straight portion (22) of tube (18) and straight portion (34) tube (32).
Body (78) has near end (80) on which is attached aiming device (14) by mounting member (27). Removed end (82) is provided having the same general, typically rectangular, cross sectional shape as body (78). This is to accommodate the receipt of adjustment means (48) onto removed end (82).
Turning now to near end (80) it is seen that a cylindrical boss (86) is integral with body (78) at near end (80). Boss (86) has a slot (88) therein, slot (88) defines a channel leading to a bore (92). With reference now to FIG. 2 it is seen that shaft (52) will slide snugly into bore (92) up to stop (56). Moreover it is seen that channel (90) of slot (88) will fit snugly adjacent ridge (54) to maintain a fixed angular orientation of standoff (50) with respect to the plane of frame (12). Release means (29) is designed to accommodate the fingers of the hand suchthat when depressed it will release friction locking holding shaft (52) in a fixed position within bore (92). Thus, while stop (56) is typically resting against frame (12) with shaft (52) within bore (92), depressing release means (29) will release friction break against shaft (52) and allow aiming device (14) to either slide fully out of bore (92) or to fix tube (18) at a selective distance between pin opening (21) and frame (12).Release means (29) has edge (29b) that is urged by leaf spring (29a) against walls of shaft (52).
Turning now to the details of adjustment means (48) and with reference to FIGS. 2 and 4 it is seen that adjustment means (48) comprises knob (94) having a surface knurled for ease of rotation. Attached to knob (94) is threaded shaft (96), having a removed end acting against a disc (98). Rotation of knob (94) will urge the removed end (96a) of shaft (96) against disc (98) to act as a friction break locating adjustment means (48) at a selectively fixed angular relationship about frame (12) with respect to receiving device (14). It can be seen then with reference to FIG. 4 that adjustment means (48) is comprised of body (100) having walls defining window (102) adjacent walls of frame (12) allowing the viewing ofindicia (84) therethrough. Central opening (104) in body (100) typically matches the rectangular cross sectional shape of frame (12) with the exception of being sufficiently large to accept disc (98) adjacent removedend (96a) of threaded shaft (96) and fixed sliding puck (99), typically plastic and notched for sliding within walls (105) of frame (12) (see FIG.4A) thus, tightening down knob (94) will urge disc (98) against walls of frame (12). This in turn will urge puck (99) against opposite walls (105) of frame (12) to prevent adjustment means (48) from sliding over frame (12). Disc (98) and puck (99) are typically made of a polymer of tetraflouraethyline sold under the trademark TEFLON or plastic material.
Noting the details of structure of release means (48) it is seen with reference to FIG. 4 that collar grips (106) have notch portion (106a) which will engage locking collar (72) of receiving device (14) when insertstub (70) is inserted into stub shaft (110) (see FIG. 4A).
Method in which release means (46) operates to maintain receiving device (16) to frame (12) is set forth in FIGS. 4 and 4A. More specifically, FIG.4A illustrates release means (46) having body (112) into which is pivotallyengaged on pins (114) collar grips (106). It is seen that spring (116) maintains collar grips (106) in a spread or outward position of the gripping portions thereof and keeps notch portion (106a) in a closed or engaged position. Thus, receipt of insert stub (70) into stub shaft (110) until locking collar (72) engages the walls thereof, while collar grips (106) are depressed and notch portions (106a) are in a split apart or spread position will, upon releasing collar grips allow notch portions (106a) to engage and hold locking collar (72). The location of notch portions (106a) and walls of body (112) engage locking collar (72) to prevent receiving device (16) from falling out of release means (46).
Thus, it is seen how use of frame (12) with adjustably mounted receiving device (16) and aiming device (14) provides for drill guide (10) which is adjustable and further provides for a device capable of drilling a tunnel or hole through bone along an axis non-parallel with that of the aiming and receiving device.
The drill guide of applicant's present device is intended to be used for any suitable arthroscopic surgery. For example, the device may be used forarthroscopic surgery to the shoulder, specifically, to reattach a torn rotator cuff tendon to the proximal end of the humerus. Briefly, the procedure of such use is as follows.
The surgeon locates the edge of the acromion. Approximately 5 cm. below that is the transverse trending axillary nerve. The puncture 6 to 8 mm. inlength is incised in the skin about 4 cm. below the acromion for insertion of the aiming device. The arthroscope has been previously inserted for viewing the drill site. The aiming device is inserted until the aiming tube opening rests adjacent to the entry site of the tunnel to be drilled,and above the axillary nerve, against the cortex of the bone. Typically, the drill will enter from the lateral cortex of the proximal humerus and exit close to the junction of the articular surface of the proximal humerus and the greater tuberosity. The axial position of the receiving device is adjusted to clear the distal end of the acromion. This positioning is accomplished by loosening the adjustment knob moving the adjustment means to the desired location and tightening the knob. A puncture wound 6 to 8 mm. in length is made for insertion of the tube of the receiving device. The receiving tube should clear the acromion and layagainst the cortex at the exit point. Final adjustments of curved ends (20)and (36) are made to position them adjacent to humerus. With the frame secured with respect to the patient and the humerus immobilized, a Nitinolpin is placed in a drill, the drill is started and inserted into the tube of the aiming device. A tunnel is drilled through the proximal humerus between the entrance and exit points adjacent the curved ends.
When the tip of the pin breaks through the exit point, the surgeon, depending upon the stitching method chosen, may pass a length of suture through the loop and pull the pin through aiming device (14), through the tunnel drilled, until the loop clears the exit point of the tunnel. The surgeon may then withdraw the suture from the loop and slide the pin the rest of the way through tube out of opening. Through the use of knot grabbers and knot pushers the suture ends may be manipulated as desired bythe surgeon to reattach the tendon, such as by passing the suture material through the tendon and the tunnel created in the humerus and securing the torn rotator cuff to bone surface. Typically, two tunnels will be provided, roughly parallel one to the other, in a similar fashion as that used in traditional open surgery for reattaching torn rotator cuffs.
While the preferred embodiment has made reference to shoulder surgery, it is to be understood that the device may be used anywhere that requires theuse of either a curved aiming device or a curved receiving device.
FIG. 5 illustrates a side elevational view of an alternate preferred embodiment of applicant's drill guide. This particular drill guide 10a provides for an aiming device (14a) which does not have a curved end. Thatis, the aiming device is capable of receiving a straight needle along its longitudinal axis, which needle will extend out the axis through the bone to be drilled. In this embodiment, the longitudinal axis of the tunnel to be drilled is generally coincident with that aiming device. However, because of obstructions, a curved receiving device (16a) may be required. That is, receiving device (16a) is provided with a curved end (36a) capable of receiving the drill bit (pin) yet deflecting yet it from its straight path through the bone. This will prevent the pin from striking sensitive areas. Of course, it is simply a matter of using receiving device (16a) with curved end (36a) as an aiming device for receipt within straight aiming device (14a). That is, the flexible pin may be inserted through the receiving device which would change its trajectory and allow astraight tunnel to be drilled through a bone along an axis non-aligned withthe aiming device, but aligned with the receiving device.
Terms such as "left", "right", "up", "down", "bottom", "top", "front", "back", "in", "out" and the like are applicable to the embodiment shown and described in conjunction with the drawings. These terms are merely forthe purposes of description and do not necessarily apply to the position ormanner in which the invention may be constructed or used.
Although the invention has been described with reference to a specific embodiment, this description is not meant to be construed in a limiting sense. On the contrary, various modifications of the disclosed embodimentswill become apparent to those skilled in the art upon reference to the description of the invention. It is therefore contemplated that the appended claims will cover such modifications, alternatives, and equivalents that fall within the true spirit and scope of the invention.
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A drill guide device for drilling straight tunnels through bone, the drill guide device having a hollow aiming tube with a curved end and a hollow receiving tube with a curved end. The aiming tube and the receiving tube are both attached to a curved frame for allowing angular adjustment between the aiming device and the receiving device. A rotating pin is inserted through the aiming tube, passes through the curved end and drills a straight tunnel through the bone where it is received into the receiving tube. The receiving tube forces the needle to curve rather than continuing on its straight path as determined by the tunnel through the bone. The curved aiming and receiving tubes allow a surgeon to work in an area which is "boxed in" by nerves, bones or the like which thereby would not allow the use of a straight drill guide.
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BACKGROUND
User feedback is currently an important mechanism by which developers of software improve the experiences of the user's who use the software. For instance, if a user provides feedback indicating that the user experience is unsatisfactory, a developer may undertake changes to the application in an effort to improve the experience of the users using the application.
Some current software systems allow a user to provide feedback. However, the user must often navigate away from a current display, and enter a specialized user feedback display. The user feedback display then dominates the user's screen and requires the user to input a fairly onerous amount of information into a user feedback form. The user must then submit the form, and only then can the user return to the application display that the user was previously viewing. This is a fairly cumbersome mechanism for receiving user feedback. Therefore, many users do not provide any feedback, whatsoever. They simply have a satisfactory user experience, or an unsatisfactory user experience, and they return to the software systems on which they have had satisfactory experiences, and tend to stay away from those systems where they have unsatisfactory experiences.
It is also currently very difficult to provide a mechanism for receiving user feedback on subtle features of a user interface. For example, if a developer changes a user interface page layout, or color, of if the developer changes the features available on a given user interface page, it is difficult to tell how the users are perceiving those changes. For instance, many user feedback mechanisms allow the user to rate an overall product, but not to rate a specific screen or user interface display. Therefore, if the user rates the product relatively low, the developer is left wondering whether it was the user interface features, the layout of the page, the function of the application, etc., which left the user with an unsatisfactory experience. Similarly, if the user rates the application relatively high, the developer is in no better position to determine precisely what parts of the application the user enjoyed.
The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter.
SUMMARY
A user interface display for software has a user satisfaction portion displayed on each page. The user satisfaction portion includes a user selectable element which allows a user to provide a user satisfaction score (or level) with a single mouse click. In response to receiving the user satisfaction level, the context of the software which the user is using is recorded, and the user satisfaction level is correlated to that context.
The captured data can be displayed to application designers and developers directly or via computed metrics. Also, the user can optionally provide additional information, including query type and other explicit feedback. The additional information can also be captured in metrics.
This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all disadvantages noted in the background.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of one illustrative embodiment of a user satisfaction scoring system.
FIG. 2 is a flow diagram illustrating one embodiment of the overall operation of obtaining a user satisfaction score in the system shown in FIG. 1 .
FIG. 3A is one embodiment of a user-selectable satisfaction indicator that can be displayed on a display screen.
FIG. 3B shows one embodiment in which the user-selectable satisfaction indicator is displayed in a user satisfaction display area of an application display area.
FIGS. 4-6 show illustrative embodiments of displays which can be generated on the user satisfaction display area shown in FIG. 3B .
FIG. 7 is a flow diagram illustrating the overall operation of the system shown in FIG. 1 in generating user satisfaction reports.
FIG. 8 is one illustrative screenshot showing a report as generated in FIG. 7 .
FIG. 9 is a block diagram of one illustrative computing environment.
DETAILED DESCRIPTION
FIG. 1 is a block diagram of one illustrative embodiment of a user satisfaction measurement system 100 . System 100 illustratively includes user satisfaction control component 102 , user interface component 104 , metric calculator 106 , user satisfaction data store 108 and report generator 110 . FIG. 1 also shows that user interface component 104 illustratively generates a display 112 , and report generator 110 generates reports, such as report 114 . FIG. 2 is a flow diagram illustrating the overall operation of system 100 shown in FIG. 1 , in generating user satisfaction measurements for a given application.
In one embodiment, user satisfaction control component 102 illustratively causes user interface component 104 to generate display 112 with a user-selectable satisfaction indicator on each screen (or form) displayed on display 112 . This is indicated by block 200 in FIG. 2 . In one embodiment, the user-selectable satisfaction indicator is always present on the user interface display so that, no matter where a user is in an application or software system, the user can easily provide user satisfaction feedback by invoking features of the user-selectable satisfaction indicator.
FIG. 3A is one exemplary screenshot of a user satisfaction indicator 250 . It can be seen in FIG. 3A that indicator 250 illustratively includes a textual description 252 such as “Rate your user experience”. That textual description 252 is then followed by a plurality of user-selectable elements 256 that range from very satisfied to very unsatisfied. In the embodiment shown in FIG. 3A , selectable elements 256 are a range of face icons that vary between a widely smiling face icon on the left and a sternly frowning icon on the right. When the user clicks on one of the icons, this indicates the level of user satisfaction that the user is currently experiencing.
FIG. 3B shows that, in one embodiment, an application or other software system generates a display such as an application display on display area 260 . FIG. 3B also shows that, in one illustrative embodiment, the user-selectable satisfaction indicator 250 is constantly displayed in a user satisfaction display area 262 . Of course, in one embodiment, the user can drag and drop the user satisfaction display area 262 to any desired location on display 260 , and that shown in the lower right hand corner of FIG. 3B is exemplary only. Also, as shown in FIG. 3A , the user may engage one of two additional control elements 258 , which allow the user to close the user-selectable satisfaction indicator 250 , or receive a further explanation as to how it is used.
In any case, in one embodiment, user-selectable satisfaction indicator 250 is always displayed on display area 262 of the display screens 260 generated by the application or other software system. Of course, while the present discussion proceeds with respect to indicator 250 being constantly displayed on display 260 , that need not be the case. Instead, indicator 250 may be displayed on only selected display screens, as desired by the developer of the software system. Constant display of indicator 250 is exemplary only.
Providing user-selectable satisfaction indicator 250 as constantly being displayed on the screens of the application can be done in any number of ways. For example, a program can be run to add code to desired pages of the application so that indicator 250 is displayed on all desired pages of an application. Alternatively, or in addition, the code can be added to only certain pages, for certain users, or users in a certain geographical area, or using any other criteria to determine when and under what circumstances indicator 250 is added to a display screen. In any case, the user-selectable satisfaction indicator 250 is illustratively displayed on the application display screens 260 .
When the user wishes to provide user satisfaction information, the user simply clicks on one of the user elements 256 on indicator 250 . In that case, user interface component 104 receives the user selection input indicative of user satisfaction and provides it to user satisfaction control component 102 . User interface component 104 also illustratively records a variety of data which can be used later in generating reports. For instance, component 104 can record context data, time data, a unique user identification, and provide all of that information to component 102 for storing (along with the user satisfaction input by the user) in user satisfaction data store 108 . Receiving the user selection input actuating one of elements 256 to indicate user satisfaction is indicated by block 202 in FIG. 2 and recording the various features of the user interface (such as context data, time data, PII-GUID data, etc.) is indicated by blocks 204 , 206 , and 208 . Block 208 is shown in dashed line to indicate that it is optional. Of course, all of the different types of data are optional, and more types of data can be added in the recording process, as desired.
The context data may illustratively include data such as the market in which the application is being used (e.g., English speaking, Chinese speaking, etc.), a particular command that the user has just input (such as the text of a search query input on a search engine), the form code of the user interface display then being displayed by the application, the version number of the application being used, or any other features that describe the context that the user is currently in, when the user provides the user satisfaction input. Of course, the context information may also illustratively include the overall configuration of the display being provided to the user, such as background color, font size, the placement of user interface elements, etc.
The time data may illustratively include when the user's session with the application began, the particular time within the session that the user satisfaction input was provided, and it may also provide the time that the user's session ends, so that it can be determined whether the user's satisfaction input was provided towards the beginning or towards the end of the user's session. Of course, all of these items of information may be tracked by the application the user is using, and retrieved by user interface component 104 , or they can be tracked by the operating system, or a combination of the two, or by other information tracking components in the computer system. In any case, the information is recorded in user satisfaction data store 108 .
After the user satisfaction measure and the data has been recorded, user satisfaction control component 102 can control user interface component 104 to generate a user selectable interface element 270 that allows a user to input additional information. For example, FIG. 4 shows one illustrative screenshot of such a user-selectable interface component 270 . The component includes a text string such as “Thank you for your feedback, tell us tiny bit more”, with the text “tell us a tiny bit more” being selectable by the user to cause a further interface element to be displayed.
If the user selects the “tell us a tiny bit more” link, then it is determined that the user wishes to provide additional user satisfaction information. Determining whether the user will provide additional feedback is indicated by block 210 in FIG. 2 . If not, then user satisfaction control component 102 causes user interface component 104 to simply generate a “thank you” message, such as message 280 shown in FIG. 6 . Generating the thank you message is indicated by block 212 in FIG. 2 .
However, if, at block 210 , the user agrees to provide additional information, then user satisfaction control component 102 causes user interface component 104 to generate another user selectable element 272 , one example of which is shown in FIG. 5 , that will allow the user to input additional information. The further information generated through element 272 will illustratively include task data that identifies the particular task that the user is attempting to perform. This allows system 100 to very clearly determine the intent of the user in using the application, at the time the user feedback is provided. In the embodiment shown in FIG. 5 , element 272 illustratively includes a text string such as “I am currently using this application to:”
Immediately below the text string is placed a drop down box 274 . When the user selects the drop down box, a drop down task list 276 is displayed which allows the user to select a task. For instance, when the application is a search application, the task might be “submit a query”, “View results”, “Modify query”, etc.
The type of tasks may also illustratively include such things as “navigation” (where a user is looking for a site), “informational” (where a user is looking for a some information), “shopping”, “getting a specific answer”, or “none of the above”.
In the embodiment shown in FIG. 5 , element 272 also includes a text box 278 which allows a user to submit additional textual comments. Element 272 further includes a cancel button 282 which allows a user to cancel the additional user feedback option, and a submit button 284 that allows a user to submit the additional user satisfaction information generated through element 272 . Generating the further information collection display 272 is indicated by block 212 in FIG. 2 , and receiving the task data identifying the user's intent is indicated by block 214 in FIG. 2 .
Once this information is received, user interface component 104 passes it to user satisfaction control component 102 which stores it in user satisfaction data store 108 for later report generation. Recording the task data is indicated by block 216 in FIG. 2 .
Again, once the user satisfaction input process is finished, the system illustratively generates the “thank you” display 280 shown in FIG. 6 .
It will, of course, be understood that in one illustrative embodiment, all of the displays in FIGS. 3A , and 4 - 6 , are provided in the user satisfaction display area 262 shown in FIG. 3B , so that the user satisfaction displays do not completely take over the application display area 260 . Therefore, the user need not navigate away from the particular screen 260 where the user initiated the user satisfaction feedback process. This provides a much simpler and more efficient mechanism for a user to provide feedback then prior systems. In addition, the collection of the task data and other context data, time data and user identification data also make it much easier to correlate the user's satisfaction input to specific features of the user interface that the user is then using.
FIG. 7 is a flow diagram illustrating one illustrative embodiment of the operation of system 100 in generating a report once sufficient user satisfaction data has been stored in data store 108 . First, it is determined that an administrator or other user desires to generate a user satisfaction report for a given software system. This is indicated by block 300 in FIG. 7 . When this happens, a variety of processing steps can take place, as desired by the person receiving the report. For instance, in one embodiment, a metric calculator 106 accesses the data in data store 108 and analyzes it to create the reports. Metric calculator 106 illustratively correlates user feedback scores indicated by the user feedback input received through element 250 to various features that were recorded. For instance, if the user inputs a high degree of satisfaction, that may illustratively be reduced to a numerical score when it stored in data store 108 . Metric calculator 106 illustratively correlates that score to the various features of the user interface that were recorded at the time that the score was input by the user. For instance, metric calculator 106 may correlate the score to the various physical features of the interface, such as the color, the background color, the foreground color, the font, the font size, the placement of user interface elements on the screen, etc.
Similarly, where the user has provided additional information, in addition to the context data, the scores can be correlated to that information as well. Therefore, if a user has provided an input indicating the type of task that the user was attempting to perform when the user satisfaction input was received, metric calculator 106 can correlate the received score to that type of task. Further, metric calculator 106 can correlate the score to the time that the score was received, to the market from which the score was received, to an individual user that input the score, to a time within a given session (whether it was toward the beginning or end of the session) that the user input was received, etc. In addition, metric calculator 106 can correlate the score to a given version of an application that the user was using. A wide variety of other correlations can be made as well, and these are mentioned for exemplary purposes only. Correlating the score to the user interface features is indicated by block 302 , correlating the scores to task types or queries is indicated by block 304 , correlating the scores to a time or version of the software is indicated by block 306 .
Once the desired correlations are made, metric calculator 106 illustratively calculates evaluation metrics for the report. Of course, a wide variety of different metrics can be used. For instance, metric calculator 106 may calculate simple averages for all user satisfaction inputs received on the application, and combine them to obtain an overall average for an application. Similarly, however, metric calculator 106 can refine the granularity so that the averages are computed for each form displayed (or for each display screen displayed when the user provided a user satisfaction input), by task type, by query or query type, by time of day, or by any other correlation criteria accessible by metric calculator 106 .
Similarly, the averages may not be simple averages, but weighted averages. In other words, it is generally accepted that a user's first and last impressions are likely to be remembered by the user. Therefore, user satisfaction scores that were input into the system early in the user's session or late in the user's session can be weighted more heavily than those input toward the middle of a user's session. Also, some task types might be more important than others in the application, or might be used more often, and therefore, the scores can be weighted based on the type of task performed. Similarly, some contexts may have received a higher number of user satisfaction inputs than others. In that case, the scores for those contexts may be weighted more heavily than other scores for other contexts. Similarly, metric calculator 106 can calculate the metrics for any of a wide variety of other correlations. Calculating evaluation metrics is indicated by block 308 in FIG. 7 , weighting them based on time is indicated by block 310 , weighting them based on task type is indicated by block 312 , calculating simple averages is indicated by block 314 , and displaying the scores or metrics based on other correlations generated is indicated by block 316 .
Once the metrics are calculated and correlated as desired, report generator 110 illustratively retrieves the information to generate report 114 . Outputting the report is indicated by block 318 in FIG. 7 .
FIG. 8 shows one exemplary screenshot of a report 400 generated using system 100 shown in FIG. 1 . Report 400 has three sections. The first section 402 indicates the overall average user satisfaction score for a given software system. Section 402 includes an experiment identification section (which may identify a particular project or study for which the report is generated), a total number of user satisfaction inputs received, and an overall average score (in this case referred to as a “smile value”) for those user satisfaction inputs. The exemplary report 400 also includes section 404 that includes overall averages by form code (by screenshot generated). The section includes an identification of the particular study or experiment being conducted, an identification of the individual form codes for which user satisfaction inputs will be received, the total number of user satisfaction inputs (smile clicks) received for each individual form code, and the overall smile value (or user satisfaction score) broken down by form code. Finally, report 400 includes section 406 that includes overall averages by query type.
In the embodiment shown in FIG. 8 , the application is a search engine. Therefore, some of the additional task information input by the user is the type of query which was input (such as navigational, finding specific information, shopping, etc.). Section 406 again includes an identification of the experiment or study being conducted, an identification of the query type for which a user satisfaction input was received, the total number of user satisfaction inputs received for each query type, and the overall average score for each query type. Again, report 400 is illustrative only and a wide variety of different reports could be generated as well.
FIG. 9 is one embodiment of a computing environment in which the invention can be used. With reference to FIG. 9 , an exemplary system for implementing some embodiments includes a general-purpose computing device in the form of a computer 510 . Components of computer 510 may include, but are not limited to, a processing unit 520 , a system memory 530 , and a system bus 521 that couples various system components including the system memory to the processing unit 520 . The system bus 521 may be any of several types of bus structures including a memory bus or memory controller, a peripheral bus, and a local bus using any of a variety of bus architectures. By way of example, and not limitation, such architectures include Industry Standard Architecture (ISA) bus, Micro Channel Architecture (MCA) bus, Enhanced ISA (EISA) bus, Video Electronics Standards Association (VESA) local bus, and Peripheral Component Interconnect (PCI) bus also known as Mezzanine bus.
Computer 510 typically includes a variety of computer readable media. Computer readable media can be any available media that can be accessed by computer 510 and includes both volatile and nonvolatile media, removable and non-removable media. By way of example, and not limitation, computer readable media may comprise computer storage media and communication media. Computer storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by computer 510 . Communication media typically embodies computer readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media. The term “modulated data signal” means a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal. By way of example, and not limitation, communication media includes wired media such as a wired network or direct-wired connection, and wireless media such as acoustic, RF, infrared and other wireless media. Combinations of any of the above should also be included within the scope of computer readable media.
The system memory 530 includes computer storage media in the form of volatile and/or nonvolatile memory such as read only memory (ROM) 531 and random access memory (RAM) 532 . A basic input/output system 533 (BIOS), containing the basic routines that help to transfer information between elements within computer 510 , such as during start-up, is typically stored in ROM 531 . RAM 532 typically contains data and/or program modules that are immediately accessible to and/or presently being operated on by processing unit 520 . By way of example, and not limitation, FIG. 9 illustrates operating system 534 , application programs 535 , other program modules 536 , and program data 537 .
The computer 510 may also include other removable/non-removable volatile/nonvolatile computer storage media. By way of example only, FIG. 9 illustrates a hard disk drive 541 that reads from or writes to non-removable, nonvolatile magnetic media, a magnetic disk drive 551 that reads from or writes to a removable, nonvolatile magnetic disk 552 , and an optical disk drive 555 that reads from or writes to a removable, nonvolatile optical disk 556 such as a CD ROM or other optical media. Other removable/non-removable, volatile/nonvolatile computer storage media that can be used in the exemplary operating environment include, but are not limited to, magnetic tape cassettes, flash memory cards, digital versatile disks, digital video tape, solid state RAM, solid state ROM, and the like. The hard disk drive 541 is typically connected to the system bus 521 through a non-removable memory interface such as interface 540 , and magnetic disk drive 551 and optical disk drive 555 are typically connected to the system bus 521 by a removable memory interface, such as interface 550 .
The drives and their associated computer storage media discussed above and illustrated in FIG. 9 , provide storage of computer readable instructions, data structures, program modules and other data for the computer 510 . In FIG. 9 , for example, hard disk drive 541 is illustrated as storing operating system 544 , application programs 545 , other program modules 546 , and program data 547 . Note that these components can either be the same as or different from operating system 534 , application programs 535 , other program modules 536 , and program data 537 . Operating system 544 , application programs 545 , other program modules 546 , and program data 547 are given different numbers here to illustrate that, at a minimum, they are different copies. They can also include the system 100 shown in FIG. 1 . System 100 can be stored other places as well, including being stored remotely.
FIG. 9 shows the clustering system in other program modules 546 . It should be noted, however, that it can reside elsewhere, including on a remote computer, or at other places.
A user may enter commands and information into the computer 510 through input devices such as a keyboard 562 , a microphone 563 , and a pointing device 561 , such as a mouse, trackball or touch pad. Other input devices (not shown) may include a joystick, game pad, satellite dish, scanner, or the like. These and other input devices are often connected to the processing unit 520 through a user input interface 560 that is coupled to the system bus, but may be connected by other interface and bus structures, such as a parallel port, game port or a universal serial bus (USB). A monitor 591 or other type of display device is also connected to the system bus 521 via an interface, such as a video interface 590 . In addition to the monitor, computers may also include other peripheral output devices such as speakers 597 and printer 596 , which may be connected through an output peripheral interface 595 .
The computer 510 is operated in a networked environment using logical connections to one or more remote computers, such as a remote computer 580 . The remote computer 580 may be a personal computer, a hand-held device, a server, a router, a network PC, a peer device or other common network node, and typically includes many or all of the elements described above relative to the computer 510 . The logical connections depicted in FIG. 9 include a local area network (LAN) 571 and a wide area network (WAN) 573 , but may also include other networks. Such networking environments are commonplace in offices, enterprise-wide computer networks, intranets and the Internet.
When used in a LAN networking environment, the computer 510 is connected to the LAN 571 through a network interface or adapter 570 . When used in a WAN networking environment, the computer 510 typically includes a modem 572 or other means for establishing communications over the WAN 573 , such as the Internet. The modem 572 , which may be internal or external, may be connected to the system bus 521 via the user input interface 560 , or other appropriate mechanism. In a networked environment, program modules depicted relative to the computer 510 , or portions thereof, may be stored in the remote memory storage device. By way of example, and not limitation, FIG. 9 illustrates remote application programs 585 as residing on remote computer 580 . It will be appreciated that the network connections shown are exemplary and other means of establishing a communications link between the computers may be used.
Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.
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A user interface display for software has a user satisfaction portion displayed on each page. The user satisfaction portion includes a user selectable element which allows a user to provide a user satisfaction score (or level) with a single mouse click. In response to receiving the user satisfaction level, the context of the software which the user is using is recorded, and the user satisfaction level is correlated to that context. The captured data can be provided to application designers and developers directly or via computed metrics.
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FIELD OF THE DISCLOSURE
[0001] The present disclosure relates generally to systems for transporting articles in an industrial setting. More particularly, the present disclosure is directed toward a self-lubricating, overhead conveyor system and the component parts thereof.
BACKGROUND
[0002] It is common in industrial settings to employ overhead conveyor systems to move articles from point to point, as may be required in many industrial applications. These overhead conveyor systems typically include an overhead track system, several trolley assemblies, a conveyor chain to join and drive the trolley assemblies along the track and turn wheel assemblies to guide the conveyor chain. The trolley assemblies have attached hangers which extend below the track to transport the desired articles along the track.
[0003] The typical overhead conveyor systems described above, while useful, suffer from several disadvantages. First, the various components of the trolley wheel systems require significant amounts of maintenance. If the components of the trolley wheel systems are not maintained properly, the system will not operate at optimal levels. As one example of required maintenance, most trolley wheel assemblies require that additional lubrication be added from time to time (the additional lubrication itself presents some problems as discussed below). The lubricant helps decrease component part wear, at least partially, by decreasing the coefficient of friction associated with the operation on the conveyor system. If the addition of lubrication is ignored, the coefficient of friction will increase, placing increased stress on the component parts, which may lead to system failure. For example, if lubrication maintenance is not performed, the friction generated by the trolley assemblies will increase. This increases the resistance the conveyor system encounters and places stress on the components of the conveyor system, as well as increasing the energy required to operate the conveyor system. Likely results will be an increase in the chain pitch (or chain length) and/or premature chain failure. If the chain pitch is increased enough, the timing of the system may be impacted, causing defects in the associated industrial processes. In either case, the conveyor system and its associated industrial process must be stopped so that sections of chain can be removed to restore the original pitch to the chain or a new chain installed. The maintenance problems are exacerbated when the trolley wheel systems are required to function in harsh environments. In these situations, the maintenance requirements for trolley wheel systems may be further increased.
[0004] As stated above, adding additional lubricants to overhead conveyor systems presents significant problems. The additional lubrication will drop from the trolley wheel system during operation, and potentially contaminate the articles carried by the trolley wheel system. The added lubricant may mix with rust that has developed on the components of the conveyor system as well, bringing additional contaminates into contact with the articles carried by the system. This phenomenon is so common in some industries (such as the poultry processing industry), it is known as “rail dust,” which is sometimes referred to as “black rain.”
[0005] Finally, the individual components of the conveyor systems are not engineered as a unit to maximize the operation and longevity of the system. As discussed above, increased friction, caused by the design of the individual components and inadequate lubrication, may cause changes in the chain pitch. Solutions to this problem have been to design trolley wheel assemblies with improved lubrication properties. However, these solutions only address part of the underlying issue. For example, a conveyor chain with improved resistance to changes in pitch could be combined with a trolley wheel assembly with improved properties, to improve the operation of the conveyor system as a whole.
[0006] Such a synergistic approach has been lacking. The present disclosure provides such an approach to describe an improved overhead conveyor system and the component parts thereof.
SUMMARY
[0007] The present disclosure describes a self-lubricating, overhead conveyor system and the component parts thereof. The conveyor system has a primary application in the manufacturing and food processing fields, but is suitable for use in any application that requires the movement of articles from point to point. The overhead conveyor system comprises three main components, a trolley assembly, a conveyor chain and a turn wheel assembly. In one embodiment, all three components are integrated to provide an improved overhead conveyor system. In an alternate embodiment, individual components as described, alone or in various combinations, are used to retrofit conventional overhead conveyor systems to increase the performance of these systems.
[0008] In operation, a plurality of trolley assemblies are configured to be removably coupled to a track system, such as an I-beam track, suspended above the ground. The individual trolley assemblies are joined together by the conveyor chain. The conveyor chain is propelled down the track by a drive means, such as a conventional drive assembly, or other device. A conventional drive assembly comprises a drive motor a reducer and drive sprockets to engage the conveyor chain. Typically, several drive assemblies are used per conveyor system. The turn wheel assemblies are located at predetermined locations along the suspended track and are configured to engage the conveyor chain. The turn wheel assemblies function to maintain the trolley assemblies and the conveyor chain in the correct orientation when the conveyor system changes direction, and to provide lubrication to the conveyor chains and to clean the conveyor chains.
[0009] In one embodiment, the trolley assemblies are self-lubricating, thereby eliminating the need for additional lubrication. The trolley assemblies are joined together by a surface hardened conveyor chain internally treated to resist corrosion and eliminate flaking. The turn wheel assemblies are configured to engage the conveyor chain and provide continuous lubrication and cleaning to the conveyor chain, eliminating the need for added lubrication. All components of the conveyor system of the present disclosure meet criteria established by the United States Department of Agriculture (USDA) for use in food processing applications.
[0010] Therefore, it is an object of the disclosure to provide a self-lubricating conveyor system. The self-lubricating conveyor system reduces drag and the coefficient of friction of the conveyor system, reducing the wear to the components of the conveyor system and increasing the life of the conveyor system. It is a further object of the disclosure to provide a trolley assembly comprising a lubricating element to eliminate the need for added lubrication to the trolley assembly. An additional object of the disclosure is to provide a trolley wheel where the lubricating element provides a barrier to reduce contamination of the trolley assembly. An additional object of the invention is to provide a conveyor system that reduces potential contamination caused by added lubricants, sometimes referred to as “rail dust.” It is a further object of the disclosure to provide a conveyor system that has an increased useful life and requires less maintenance than conventional conveyor systems. An additional object is to provide a trolley assembly that eliminates the possibility of pre-loading the trolley wheel assembly. It is a further object of the invention to provide a conveyor system that meets all applicable U.S.D.A. regulations and requirements and is suitable for use in food processing operations.
[0011] The above stated objects of the invention are alternative and exemplary objects only, and should not be read such that all objects and advantages are required for the practice of the invention in every embodiment described. The above objects and advantages are neither exhaustive nor individually critical to the spirit and practice of the invention. Other or alternative objects and advantages of the present invention will become apparent to those skilled in the art from the following description of the invention.
BRIEF DESCRIPTION OF THE FIGURES
[0012] [0012]FIG. 1 shows one embodiment of the overhead conveyor system of the present invention, illustrating the interaction of the trolley wheel assembly with an I-beam track;
[0013] [0013]FIG. 2A shows a front view of one embodiment of the trolley wheel;
[0014] [0014]FIG. 2B shows a side view of one embodiment of the trolley wheel;
[0015] [0015]FIG. 3 shows a partially exploded side view of the trolley wheel assembly detailing the interaction of the fastening means with the trolley wheel;
[0016] [0016]FIG. 4A shows a cutaway view of one embodiment of the ball bearing assembly;
[0017] [0017]FIG. 4B shows the interaction of the fastening means with the trolley wheel and the ball bearing assembly;
[0018] [0018]FIG. 5 shows a partially exploded side view of one embodiment of the conveyor chain;
[0019] [0019]FIG. 6 shows a side view of one embodiment of the conveyor chain interacting with the trolley wheel assembly;
[0020] [0020]FIG. 7 shows a partially exploded side view of one embodiment of the turn wheel assembly;
[0021] [0021]FIG. 8A shows one embodiment of the tooth profile of the individual teeth comprising the tooth segments of the turn wheel assembly; and
[0022] [0022]FIG. 8B shows an alternate embodiment of the tooth profile of the individual teeth comprising the tooth segments of the turn wheel assembly.
DETAILED DESCRIPTION
[0023] Trolley Assembly
[0024] The trolley assembly 10 of the present disclosure is adapted for use with an I-beam track 50 of conventional design as shown in FIG. 1. The track 50 comprises a support 52 with two laterally inclined flanges 54 to support and guide a plurality of trolley assemblies 10 . In one embodiment, each trolley assembly 10 comprises a pair of trolley wheels 100 , each wheel 100 removably coupled to a trolley bracket 150 by a fastening means, illustrated in FIG. 1 as bolt 180 and bushing 182 . Each trolley wheel 100 further comprises a self-contained ball bearing element 200 .
[0025] The trolley brackets 150 are of standard design and comprise an angular upper portion 152 and a depending flanged portion 154 . The angular upper portion 152 forms a recess to receive the trolley wheels 100 in a manner so that trolley wheels 100 can engage the lateral flanges 54 of the track 50 . Two trolley brackets 150 are removably secured together at apertures 154 at 156 and 158 by bolts or other means. Flanges 154 comprise a notched portion 160 between 156 and 158 to receive the conveyor chain 300 (as described below). Sandwiched between the flanges 154 is a hanger bracket 162 to receive a hook 164 to support the load carried by the trolley wheel assemblies 10 .
[0026] The trolley wheel 100 comprises a front side 102 , a back side 104 and an outer peripheral surface 106 adapted to engage the track 50 (see FIG. 2A and FIG. 2B). The peripheral surface 106 joins the front side 102 and back side 104 of wheel 100 . The rear side 104 contains a chamber 110 adapted to receive the bearing element 200 . The chamber 110 is of sufficient dimensions to receive the bearing element 200 , with the exact dimensions depending on the configuration of bearing element 200 and the material composition of the trolley wheel 100 . In one embodiment, the radius of the chamber 110 is in the range of 39.5 to 41.5 millimeters. A radius of 40.0 millimeters will receive a bearing element 200 such that the bearing element 200 will not separate from the trolley wheel 100 (when the trolley wheel 100 is manufactured from Delrin® and assembled as discussed below). In addition, a cover 185 may be sonically welded over the chamber 110 to further prevent separation of the bearing assembly 200 from the trolley wheel 100 . The cover 185 also serves as a barrier to prevent against contamination of the trolley wheel 100 and the bearing assembly 200 . The front side 102 contains an opening 108 to receive the fastening means (bolt 180 and bushing 182 ). The outer peripheral surface 106 may be designed to incorporate an angle (as shown in FIG. 2B). The angle functions to improves transit of the trolley wheel 100 along the track 50 by reducing drag, and allows the trolley wheel 100 negotiate turns in the track 50 more efficiently. In one embodiment the angle of the outer peripheral surface ranges from 5 to 15 degrees as measured from the back side 104 to the front side 102 . In an alternate embodiment, this angle is 7 degrees.
[0027] The width of the trolley wheel 100 is less than conventional trolley wheels. In one embodiment, the width of the outer peripheral surface 106 of the trolley wheel 100 is approximately 19 millimeters (FIG. 2B). The decreased width of trolley wheel 100 further decreases the coefficient of friction of the trolley wheels 100 against the track 50 . Conventional trolley wheels were designed with increased width in order to increase the load bearing capacity of the trolley wheel. As discussed below, due to the novel bearing assembly 200 and fastening means incorporated into trolley wheels 100 , load capacities can be increased without increasing the width of the trolley wheels 100 .
[0028] The trolley wheel 100 is manufactured from a polymer material. In one embodiment, any resin marketed under the Delrin® series trade name (Delrin® trademark registered to E. I. du Pont de Nemours and Company; properties of Delrin® are described in technical literature accessible at www.dupont.com: 8501/custom/plastics1/) is used as the polymer. One example is the acetyl homo-polymer form of Delrin® is used as the polymer. However, other polymers can be used, including, but not limited to, ultra-high molecular weight (UHMW), polypropylene, polyethylene or Teflon. Suitable polymers may exhibit resistance to compression, low drag characteristics and be able to function efficiently in a wide range of environmental conditions, as well be resistant to chemical reagents used in cleaning and maintenance of conveyor systems. The design of the trolley wheel 100 (in combination with the bushing 182 and cover 185 ) is designed to act as a protective shield against contamination of the ball bearing assembly 200 .
[0029] The fastening means comprises a bolt 180 and bushing 182 . The bushing 182 is manufactured from a polymer material to resist compression. The polymer material may be the same polymer material used in the construction of the trolley wheels 100 , although other polymer materials may also be used. The bushing may be glass fibre filled to further resist compression. In one embodiment, the bushing is in the range of 15-35% glass fibre filled. The bushing 182 is configured with a crown 184 adapted to interact with opening 109 of the cover 185 and opening 214 of the bearing assembly 200 to allow self-adjustment of the trolley wheel 100 (FIG. 3). This self-adjustment allows the trolley wheel assemblies 10 to negotiate turns in track 50 without undergoing compression or impinging on track 50 , which can lead to increased friction and drag, thereby reducing the efficiency of the conveyor system and increasing the stress applied to the components of the conveyor system. In addition, the bushing 182 has a back portion 186 . One function of the back portion 186 is to provide separation of the back side 104 of the trolley wheel 100 with the trolley bracket 150 . If the length of the back portion 186 is not sufficient, then trolley bracket 150 will impact the back side 104 of the trolley wheel 100 , damaging the wheel. In one embodiment, the length of the back portion 186 is in the range of 8-12 millimetres. A length of 10.5 millimetres for back portion 186 is sufficient to allow for compression caused by the tightening of bolt 180 and prevent trolley bracket 150 from contacting the back side 104 .
[0030] Bolt 182 can be manufactured from a variety of materials, including stainless steel and carbon steel. In one embodiment, the bolt 182 is manufactured from carbon steel that is treated to resist corrosion (as described below for the conveyor chain). Bolt 182 has a bolt head 190 . The bolt 182 is placed through opening 108 of the trolley wheel 100 , opening 214 of the bearing assembly 200 and opening X of the trolley bracket 150 . The bolt head 190 rests against the inner race 202 of the bearing assembly 200 . The bolt 182 is secured by a nut 192 . As the nut 192 is secured on bolt 182 , the bushing 180 is compressed and bolt head 192 is tightened against the inner race 202 . In this manner, bolt head 190 clamps inner race 202 in place, preventing the inner race 202 from free rotation about the axis of bolt 182 . The bolt head 190 is designed so that it does not extend past the plane formed by the front side 102 . In one embodiment, the bolt head 190 is not greater than {fraction (1/8)} inch thick. If the bolt head 190 does extend beyond the plane formed by the front side 102 , the bolt head 190 may contact the support 52 or flanges 54 of track 50 , created metal to metal contact. This contact increases the coefficient of friction and creates contamination.
[0031] The ball bearing assembly 200 comprises an inner race 202 and an outer race 204 joined together by a floor 206 (FIG. 4A). The inner race 202 , outer race 204 and floor 206 define a raceway 208 to receive the balls 210 . The floor 206 may contain a channel to provide a groove in the raceway 208 through which the balls 210 may travel.
[0032] The bearing assembly 200 is a self contained unit that is incorporated into the trolley wheels 100 at cavity 110 . The inner race 202 and the outer race 204 are of unitary construction. Conventional trolley wheel assemblies traditionally utilize a two piece inner race assembly. The inner race serves several purposes in the trolley wheel. First, the inner race provides a shoulder for the fastening means that couples the trolley wheel to the trolley bracket. Second, the inner race defines a portion of the raceway for the rotation of the balls in the bearing assembly. By increasing or decreasing the torque applied to the fastening means, the internal clearance of the raceway in a two-piece inner race assembly can be altered (as the relative positions of the components of the 2-piece inner race are changed) to the point that the balls no longer have a free rotation in the raceway. This creates what is known as a pre-loading condition. The pre-loading condition affects the inertia of movement of the trolley wheel, requiring additional torque to rotate the trolley wheel (this condition is referred to as drag). In the present disclosure, the trolley wheels 100 are secured to the trolley brackets 150 by a fastening means, illustrated in FIGS. 1 and 4B as bolt 180 and bushing 182 . The bolt 180 is designed such that the head 190 and the crown 184 of the bushing 182 contacts only the inner race 202 of the bearing assembly 200 (FIG. 4B). Since the inner race 202 is of unitary construction, altering the torque of the fastening means will not result in a pre-load condition.
[0033] In addition, in conventional trolley wheels, the outer race is often an integral portion of the trolley wheel itself, comprising a stainless steel band attached directly to the inner portion of the trolley wheel. Since the outer race is an integral part of the trolley wheel, movement of the trolley wheel could also alter the internal clearance of the raceway, leading to the problems described above. As a result, conventional trolley wheels have a measured inertia of approximately 0.014 Vs. Due to the self-contained nature of the bearing assembly 200 and the self-lubricating properties of the trolley wheels 100 , the trolley wheels 100 of the present disclosure have a measured inertia of approximately 0.001 Vs.
[0034] In one embodiment, the bearing assembly 200 is not fully loaded, meaning that the balls 210 are separated by bearing cages (sometimes referred to as spacers) 212 (FIG. 4A). Conventional trolley wheel assemblies generally incorporate full complement, non-precision balls. The full complement state, while decreasing the cost of the bearing assembly and increasing the load the bearing assembly can support, leads to increased friction being generated as the balls interact with one another and decreased speeds of travel for the trolley wheel assemblies. The use of a non-full complement state in bearing assembly 200 eliminates these difficulties. A further improvement is directed towards the balls 210 of the bearing assembly 200 . The bearing assembly 200 incorporates precision ground balls. In one embodiment, ABEC 1 standard precision ground stainless steel balls are used. The used of precision ground balls 210 leads to the elimination of the increased friction and drag created when non-precision ground balls are used (as in conventional trolley wheel assemblies). In addition, bearing assembly 200 may incorporate a groove to guide the balls 210 in raceway 208 . The use of a non-full complement state combined with the use of precision ground balls 210 and groove in bearing assemblies 200 increases the performance of the trolley assemblies 10 over conventional trolley wheel assemblies.
[0035] The trolley wheel assemblies 10 of the present disclosure also comprise a self-lubricating means, shown as cured graphite mixture 24 in FIG. 4A. As a result, the trolley wheel assemblies 10 do not require additional lubrication over their lifetime. In one embodiment, a mixture of liquid graphite is poured into the raceway 208 of the bearing assembly 200 . The graphite mixture encapsulates the balls 210 and the bearing cages 212 , filling substantially all of the raceway 208 (FIG. 4A). The liquid graphite material comprises a mixture of graphite and phenolic resin, although other mixtures can be used, including but not limited to, graphite and MOS. The bearing assembly 200 with the added liquid graphite is then heated in a furnace to cure the liquid graphite. Typical temperature ranges for heating are from about 250 degrees Fahrenheit to about 650 degrees Fahrenheit. The curing time for the liquid graphite is about 1-6 hours. The tumbling of the balls 210 against the cured graphite 24 or other lubricating means allows lubricant to leach out over time, continuously lubricating the balls 210 . Once cured, the graphite 24 becomes a permanent part of the bearing assembly 200 and provides permanent lubrication to the bearing assembly, obviating the need for added lubricants. The cured graphite 24 is inherently more stable than petroleum lubricants and has a much lower coefficient of friction. The reduced coefficient of friction is due in large part to the reduction in inertia drag created the bearing assembly 200 begins to rotate. When petroleum based lubricants are used in conventional bearing, the inertia drag is created by the channelling effect as the balls must create a path through the petroleum lubricant. In the current disclosure, the cured graphite moves with the balls 210 , virtually eliminating inertia drag and reducing the coefficient of friction.
[0036] In the bearing assembly 200 of the present disclosure, increased loads can be tolerated because of the reduced coefficient of friction created by the design of the bearing assemblies 200 as discussed above. Due to the fact that the bearing assembly 200 can sustain increased loads, the width of the trolley wheel 100 can also be decreased, as discussed above.
[0037] Conventional trolley assemblies generally incorporate oil or grease lubricants which, after time, loose their effectiveness requiring that additional lubricants be added. The added lubricants are liquids which escape from the trolley wheels and accumulate on the track and the trolley brackets, where the added lubricants mix with rust and other contaminants. This mixture of added lubricants and contaminates then drops onto the articles carried by the overhead conveyor system. In the poultry industry, this phenomenon is referred to as “rail dust.”
[0038] In addition to providing a lubricating function, the cured graphite 24 forms a seal, preventing dust, powders, and micro-particle contaminant from entering the bearing assembly 200 and clogging the raceway 208 . In addition, the seal prevents corrosion of the balls 210 and bearing cages 212 that may be caused by cleaning solutions and contaminants.
[0039] Unlike commonly used petroleum based lubricants, the cured graphite 24 will not be washed out of the bearing assembly 200 by steam, solvents, acids or alkalis used to clean the overhead conveyor systems. In addition, the cured graphite 24 exhibits virtually no out gassing when used in vacuum applications. The cured graphite 24 functions in a wide range of operating conditions without significant changes in starting torque or lubricity (as described above). The cured graphite has an operating range of about −250 degrees Fahrenheit to about 650 degrees Fahrenheit.
[0040] The trolley assemblies 10 represent a significant advance over conventional trolley assemblies for use on overhead conveyor systems by virtue of the design of trolley wheels 100 , the use of self-lubricating bearing assembly 200 and the fastening means (bolt 180 and bushing 182 ). First, the trolley assemblies 10 obviate the need for additional lubrication. This decreases the maintenance time and cost associated with currently available overhead conveyor systems. In addition, the trolley wheels 100 of the present disclosure reduce the coefficient of friction by approximately 50%. Existing trolley wheels using the currently available forms of lubrication have a coefficient of friction in the range of 0.049. However, the trolley wheels 100 of the present disclosure have a coefficient of friction in the range of 0.026. As a result of decreasing the coefficient of friction of the trolley wheels 100 , the stress applied to the components of the overhead conveyor system is decreased, thereby increasing the life of the components of the system. For example, the life of the conveyor chain 300 is increased by decreasing the stress placed on the conveyor chain 300 as a result of the reduced coefficient of friction applied by the trolley wheel assemblies 10 .
[0041] Conveyor Chain
[0042] The conveyor chain 300 comprises a series of split halves 302 A and 302 B, the split halves being joined together by a fastening means, illustrated as I-pin connector 304 to form links 306 (FIG. 6). The split halves 302 A and 302 B and the I-pin connector 304 define at least one cavity 307 in each link 306 . The links 306 of chain 300 are separated by center link 308 , which is sandwiched between the split halves 302 A and 302 B and is also secured to the split halves 302 A and 302 B by I-pin connector 304 as illustrated in FIGS. 5 and 6. The distance between the centers of adjacent cavities 307 is referred to as the chain pitch. The chain pitch for most chains used in industrial processes (such as the poultry industry) is 76.5 millimetres. Central link 308 of chain 300 engages the trolley brackets 150 at notch 160 on flanges 154 (see FIG. 1 and FIG. 5). In this manner, a plurality of trolley wheel assemblies can be joined together by chain 300 to drivingly engage the trolley wheel assemblies 10 down the track 50 of the overhead conveyor system.
[0043] The chain 300 may be constructed from a variety of materials. In one embodiment, chain 300 is manufactured from cold haul quality (CHQ) steel, however other materials can be used, including, but not limited to micro-alloy steel. The I-pin connector 304 can also be made from CHQ steel. The chain 300 and I-pin connector 304 is surface hardened to about 75 Rockwell to resist stretching/changes in chain pitch, which can lead to timing errors in the conveyor system. In addition, the chain is impregnated with silicon nitride to resist corrosion and to prevent flaking that occurs in conventional chains that are simply plated with anticorrosion materials, such as zinc. The flaking off of plating materials can contaminate the environment, including the articles transported by the overhead conveyor system. In addition, areas where the plating material has been removed can provide unprotected areas that may lead to rust, corrosion and deterioration, providing a further source of contamination and decreasing chain life.
[0044] In the treatment process, the components of the chain 300 are hardened at approximately 1600 degrees F. and quenched in oil to temper. The parts of chain 300 are then placed in a furnace and covered with sand. The parts of chain 300 are heated to slightly below the tempered heat (ranging from 25-50 degrees F. below the tempered heat), which is approximately 1050-1150 degrees F. The sand bed is then injected with gasses containing silicon nitride and subject to vibration. As a result, the chain components pass through the sand bed. During this process two layers are formed, a first inner layer termed the white layer and a second outer layer which is ceramic in nature. The second layer is supported by a chemically enhanced diffusion zone and is ceramic in nature. During this process, the chain is also “lapped” which removes burrs and rough edges. This reduces the knifing effect often seen in conveyor chains as the rough edges of the chain components interact with one another. The second outer layer reaches a hardness of approximately 75 Rockwell and exhibits a microporosity that when quenched in H1 or H2 oil further protects the components of chain 300 and increases their lubricity during the chain wear in.
[0045] The strength of chain 300 , in addition to resisting changes in pitch and the problems associated therewith, allows the conveyor system to operate at an increased tension. As a result, trolley wheel assemblies 10 can be placed on 12 inch centers, rather than 6 inch centers. In conventional conveyor systems, when trolley wheel assemblies were placed on 12 inch centers, the conveyor chain sagged in the middle, causing problems with chain timing and the industrial processes associated therewith. Conventional chains lacked the strength to be placed under sufficient tension to make the use of 12 inch centers feasible. By using 12 inch centers, the number of trolley wheel assemblies can be reduced by half, decreasing the cost of the system and simplifying operation.
[0046] Turn Wheel Assembly
[0047] The turn wheel assembly 400 functions to guide the conveyor chain 300 by maintaining the chain 300 in the vertical plane when the overhead conveyor system changes direction (FIG. 7). In one embodiment, the turn wheel assembly 400 a solid disk of material, such as UHMW. A groove 402 is machined in the disk of material, creating an upper shelf 404 A above the groove 402 and a lower shelf 404 B below the groove 402 (FIG. 7). The groove 402 is created such that the internal arc has an internal dimension to receive a plurality of tooth segments 406 such that the tooth segments 406 can interact with the links 306 of chain 300 . The internal dimension of the arc 402 will vary depending on the diameter of the turn wheel 401 . In one embodiment, the turn wheel 401 has a diameter of 19 inches and the internal arc of groove 402 has a diameter of 13.125 inches (334.4 millimetres). When the turn wheel 401 has a diameter of 24 inches, the internal arc of groove 402 has a diameter of 14.750 inches (374.7 millimetres). The exact dimensions of the groove 402 will depend on the configuration of the tooth segments 406 , and such modifications are within the ordinary skill in the art. The tooth segments 406 are removably secured in place by a securing means, illustrated as bolt 408 A and nut 408 B. The securing means pass through the upper shelf 404 A, the tooth segments 406 and the lower shelf 404 B. The securing means exert a clamping effect on tooth segments 406 such that a force is applied to the tooth segments 406 that push the tooth segments outward. This force combats the force that will be applied to the tooth segments 406 as they interact with chain 300 , which is typically in the range of 30 ft/lbs.
[0048] Each tooth segment 406 comprises at least one tooth. In one embodiment illustrated in FIG. 7, each tooth segment 406 comprises 2 teeth 410 A and 410 B. The individual teeth are spaced a distance apart so that each tooth on tooth segment 406 engages each link 306 of chain 300 so that each tooth is inserted in a cavity 307 . In the embodiment illustrated in FIGS. 6 - 8 , the individual teeth 410 A and 410 B are spaced approximately 76.5 millimetres apart, with the same spacing being maintained between individual teeth on adjacent tooth segments 406 . This distance corresponds with the chain pitch of the conveyor chain 300 described herein. The distance between teeth can be varied to adapt to chains with different pitches, with such modification being within the ordinary skill in the art. Each tooth segment 406 may comprise a greater or lesser number of individual teeth, so long as the spacing of the individual teeth is such that each tooth on tooth segment 406 engages each link 306 of chain 300 so that each tooth is inserted in a cavity 307 . The number of tooth segments 406 per turn wheel assembly 400 can also be varied, depending on the diameter of the turn wheel 400 . In the embodiment illustrated in FIG. 7, the turn wheel assembly can accommodate 5 tooth segments 406 . The number of individual tooth segment 406 per turn wheel 400 can be varied as long as the spacing of the individual teeth is such that each tooth on tooth segment 406 engages each link 306 of chain 300 so that each tooth is inserted in a cavity 307 .
[0049] The individual teeth comprising the tooth segments 406 are designed with a profile to maximize the insertion of the individual teeth into cavity 307 of the links 306 . In one embodiment, the individual teeth 410 A and 410 B are rounded at their periphery 412 , to produce stub tooth design (FIG. 8A). The stub tooth design interacts with cavity 307 of link 306 in a fluid fashion and minimizes the contact of the outer periphery 412 of the individual teeth with the components of the chain 300 , which can result in cupping of the individual teeth. The cupping effect is the result of the links 306 of the conveyor chain 300 contacting the teeth in a manner so that the individual teeth do not cleanly engage cavity 307 of link 306 , but instead contact the components of the chain 300 , such as the split halves 302 A and 302 B, as they are inserted into cavity 307 . Such a situation can occur when slack is introduced in the chain 300 (effectively changing the chain pitch), or when the conveyor chain timing is not in register with the turn wheel. Although the chain 300 eliminates almost all stretching of chain 300 , when turn wheel assemblies of existing overhead conveyor systems that do not use chain 300 are retrofitted with tooth segments 406 of the present disclosure (as discussed below), such stretching of the conveyor chains may, and often does, occur. The stub tooth design eliminates the cupping problems caused by chain stretching and incorrect timing, as the components of the conveyor chain slide against the rounded outer periphery 412 of the individual teeth with less contact than when the individual teeth incorporate a drive tooth design (FIG. 8B). In addition, since the outer periphery 412 of the individual teeth 410 A and 410 B is symmetrical, when one face of the outer periphery of the individual teeth becomes worn, the tooth segment can be removed and orientation of the tooth segments 400 in the turn wheel assembly can be reversed, extending the useful life of the tooth segments 406 .
[0050] Although the stub tooth design described above offers certain advantages, other configurations of the individual teeth may be employed in the present disclosure. An alternate embodiment of the design of the individual teeth comprising the tooth segments 406 is shown in FIG. 8B. In this embodiment, the individual teeth 410 C and 410 D of tooth segment 406 have a roughly triangular, or drive tooth, design. The teeth 410 C and 410 D are spaced as described above for teeth 410 A and 410 B, and the same variations described above apply.
[0051] The tooth segments 406 (regardless of the design of the individual teeth) are formed from a capillary polymer material. The capillary polymer material is extruded and then molded into the desired tooth segment configuration (described above). The polymer material has an internal honeycomb structure that is impregnated with an USDA approved lubricant. In one embodiment, this lubricant is H2 oil, however other lubricants may be used, including, but not limited to H1 oil. The lubricant is introduced into the polymer mixture before it is extruded so that the lubricant is substantially uniformly incorporated into the structure of the polymer material.
[0052] In one embodiment, the method for producing the polymer material comprises hand-packing the polymer material (with added lubricant) into an appropriate mold. Once the mold is secured the polymer material is baked in an oven at approximately 350 degrees F. to cure. The polymer is removed from the mold and allowed to air cool. In one embodiment, the polymer is cast into blocks for each tooth segment. The blocks are then machined to produce the desired configuration for the individual teeth to produce the finished tooth segment 406 . In another embodiment, the individual teeth can be molded in their desired configuration to produce the finished tooth segment 406 .
[0053] As the individual teeth of the tooth segments 406 interact with the chain 300 , heat is generated as a result of friction between the teeth and components of chain 300 . As a result of the design of the individual teeth and the chain 300 , the outer periphery of the individual teeth contact the interior of the cavity 307 (composed of split halves 302 A and 302 B) and the base of the tooth segment contacts the sides of the chain (as illustrated in FIG. 8 for teeth incorporating the stub tooth design). If desired, turn wheel assemblies 400 can be placed on opposite side of the chain 300 to ensure that the tooth segments 400 contacts the maximum area of chain 300 . The change in temperature causes the lubricant trapped inside the honeycomb structure of the polymer to be released during use. As a result, the tooth segments 406 of turn wheel assembly 400 apply a constant light film of lubricant to the chain 300 , especially the components of the links 306 . This makes the turn wheel assembly 400 an automatic lubricating device in addition to its other functions. The stub tooth design of the individual teeth assures that the lubricant is applied to a substantial portion of the chain 300 . This coating of lubricant deters rusting or corrosion and provides a protective barrier to chain 300 . In addition, the insertion of the individual teeth of the tooth segments 406 into cavity 307 removes any existing rust and corrosion that may be present on the chain 300 . As a result, the useful life of the chain 300 is increased and the maintenance required is reduced. Since the chain 300 is constantly lubricated, the need for additional chain lubrication is obviated, reducing the possibility that lubricant will come into contact with the items carried by the conveyor system and reducing the occurrence of “rail dust” and similar phenomenon.
[0054] When the lubricant is released from one or more honeycomb structures, the honeycomb structure collapses, and the residual polymer is removed by the friction between the chain 300 and the individual teeth on the tooth segments 406 . Since the polymer material is comprised of an essentially homogenous honeycomb structure, lubricant continues to be release from successive honeycomb structures. As a result of continuous lubrication, the tooth segments 406 have a finite service life. In prototypes used by Applicant, the tooth segments 406 have a life of approximately 7 months. The life to the tooth segments 400 is dependent on line tension and line speed, with the 7 month life based on an average chain speed of 78 RPM. The turn wheel assembly 400 is designed so that individual tooth segments 406 may be easily replaced as desired without removing the entire turn wheel assembly 400 , and without replacing the entire turn wheel assembly 400 . For replacement, the securing means, in this embodiment bolt 408 A and nut 408 B, a removed, a new tooth segment 406 inserted and the securing means reinserted.
[0055] Conventional turn wheel assemblies generally do not employ tooth segments as does the turn wheel 400 of the present disclosure. Instead, conventional turn wheel assemblies employ a smooth material on the surface of the turn wheel assembly that contacts the chain. In other words, conventional turn wheel assemblies function only to keep the chain in the correct plane. Tooth segments 406 are designed so that conventional turn wheel assemblies may be retrofitted with the tooth segments 406 of the present disclosure. Through such retrofitting, the conventional turn wheel assemblies are converted into automatic lubricator, with the advantages discussed above.
[0056] Advantages
[0057] The components of the overhead conveyor system of the present disclosure offer maximal benefit when all the components described, the trolley assembly 10 , the conveyor chain 300 and turn wheel assembly 400 , are incorporated. However, it is within the scope of this disclosure that the individual components may be incorporated (either alone or in various combinations) into existing overhead conveyor systems, thereby improving the performance and extending the life of the existing overhead conveyor systems. As one example, and not meaning to exclude additional examples, the tooth segments 406 may be solely incorporated into existing turn wheel assemblies as discussed above.
[0058] As discussed in this specification the use of the conveyor system of the present disclosure significantly extends the overall life of the conveyor system and decreases the maintenance costs associated with the system. These factors result in significant costs savings to the operator of the overhead conveyor system. An example of the cost savings using the overhead conveyor system of the present disclosure makes this point. The following example uses USDA average numbers for existing overhead conveyor systems.
[0059] A typical conveyor system has a chain length of 600 feet. The average life of a chain is approximately 14 months, with the cost of the chain being $20 per foot, plus $2,400 for installation of the track (based on 30 man hours/installation at $80/man hour). Under normal operating conditions, an average overhead conveyor system processes 91 birds per minute.
[0060] The cost/foot of conveyor chain 300 is $59.95. In order to compare the cost of the conveyor chain 300 to the average cost of conventional conveyor chains, the increased life and decreased maintenance cost of the conveyor chain of the present disclosure must be taken into account. The conveyor chain 300 has an estimated life of approximately 42 months, or 3 times the average life of conventional conveyor chains. Taking into account the fact that three conventional chains (at $20/foot) must be used to equal the expected life of chain 300 , the base cost of conventional conveyor chains is $60/foot. Adding the manpower cost to replace the conveyora chain 2 times ($4,800, at a cost of $2,400/installation) the cost of the average 600 foot conveyor chain increases another $8/foot.
[0061] The increased maintenance costs of conventional conveyor chains must also be taken into account. As discussed above, on average 15 minutes/day is spent lubricating and cleaning conventional conveyor chains. Based on a 5 day work week, 52 weeks/year, an average of 65 hours per year is spent on this type of maintenance. At $30/man hour, this is $1,950/year. Since the conveyor chain 300 does not require lubrication or cleaning when used in conjunction with turn wheel assembly 400 , this maintenance cost is not incurred. Over the 42 month life of the conveyor chain 300 , this amounts to a total savings of $6,825. For a typical 600 foot chain, this adds an additional $11.38/foot costs to the use of conventional conveyor chains.
[0062] Finally, the conveyor chain 300 , because of its superior properties, allows overhead conveyor systems to operate more efficiently, resulting in savings in energy cost of the life of conveyor chain 300 . An average conveyor line utilizing convention conveyor chains draws an average of 12.7 Amps 460 volts, which is equal to 5.8 Kilowatts (kw)/hr. At an average cost of $0.04 per kw/hr and assuming 16 hours of operation/day, the total energy cost is $3.68/day for a conveyor system utilizing conventional conveyor chains. Operating 5 days/week, 52 weeks/year, this amounts to a total energy cost of $956.80/year. The use of the conveyor chain 300 reduces the energy consumption of an overhead conveyor system by 30%, a savings of $287.04/year. Over the 3.5 year (42 month) life of conveyor chain 300 , this amounts to a total savings of $1007.80. For a typical 600 foot chain, the additional energy cost in using conventional conveyor chains adds an addition cost of $1.68/foot.
[0063] Adding these costs together, the total cost for the use of conventional conveyor chains is $81.06/foot. The cost of using conveyor chain 300 is $59.95/foot. Therefore, the use of conveyor chain 300 results is a savings of $21.11/foot, a 26% cost savings over the life of the conveyor chain 300 .
[0064] In addition to the cost savings associated with the procurement and maintenance of the conveyor chain 300 , cost savings are also realized when lost production issues are considered. On average, 7 minutes/day production time is lost due to problems with conventional conveyor chains. These problems require the entire conveyor system be shut down, and are generally caused by removing chain slack from the conveyor chain (caused by increases in chain length/pitch), or dealing with problems associated with chain slack. Assuming a 5 day work week, 52 weeks/year, this amounts to 1,820 minutes/year. As a cost of $660 per lost minute of production, this amounts to a cost of $1,202,200/year. As discussed in detail above, the conveyor chain 300 is specially designed to virtually eliminate chain slack when used in the overhead conveyor system of the present disclosure. Therefore, the lost production costs are avoided when conveyor chain 300 is used. Over the 3.5 year life of the conveyor chain 300 , the total savings realized is $4,202,200.
[0065] Production loss must also be considered when calculating total cost savings. One of the most common causes of lost production is chain stretch. The more a chain stretches, the more links of chain must be removed in order to ensure the overall chain length remains constant. If chain length does not remain constant, then the timing of the conveyor system may be adversely impacted, with adverse impact on the associated industrial process. An average conveyor chain will stretch 2 inches per 10 feet of chain, with 70% of this stretch occurring in the first 5 weeks of use. This chain stretch of 2 inches per 10 feet will result in a loss of capacity equal to one bird for every 30 feet of chain (based on 6 inch centers). For a 600 foot chain, this is a loss of capacity equal to 20 birds per conveyor system complete revolution. A conveyor system with a 600 foot chain processing 91 birds/minute will make a complete revolution every 13.18 minutes. In a 16 hour operating day, a conveyor system makes 72 complete revolutions. At a loss of 20 birds per revolution, a total capacity of 1,440 birds is lost per day. Assuming a 5 day work week, 52 weeks per year, a capacity of 374,400 birds is lost per year. Over the 3.5 year (42 month) life of conveyor chain 300 , a total capacity of 1,310,400 birds is lost. Assuming an average 5 pound bird at $0.50 per pound, each bird lost represents a loss of $2.50. Multiplied by the total number of birds lost, the total cost for the lost capacity over the life of conveyor chain 300 is $3,276,000.
[0066] The total cost due to production lost due to downtime and production lost due to lost capacity (chain stretch) is $7,478,200 when using conventional overhead conveyor systems. As discussed in detail above, the conveyor chain 300 is specially designed to virtually eliminate chain slack when used in the overhead conveyor system of the present disclosure, thereby eliminating the costs attributable to lost production.
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Described are a self-lubricating, overhead conveyor system and the component parts thereof. The self-lubricating overhead conveyor system obviates the need for added lubricants, and comprises three main components: a trolley assembly, a conveyor chain and a turn wheel assembly. In one embodiment, all three components are integrated to provide an improved overhead conveyor system; however, individual components may be used to retrofit conventional overhead conveyor systems. The trolley assemblies contain a self-lubricating precision ball bearing assembly, and are joined together by a surface hardened conveyor chain internally treated to resist corrosion and eliminate flaking. The turn wheel assemblies are configured to engage the conveyor chain and provide continuous lubrication and cleaning to the conveyor chain. All components of the conveyor system of the present disclosure meet criteria established by the United States Department of Agriculture (USDA) for use in food processing applications.
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CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] This application claims the benefit of U.S. Provisional Application No. 61/568,615 filed Dec. 8, 2011, which is entirely incorporated herein by reference.
BACKGROUND OF THE DISCLOSURE
[0002] The present disclosure is directed towards systems and methods for treating tissue of a body and more particularly, towards approaches designed to treat a natural joint and conditions involving the patella specifically.
[0003] A joint is the location at which two or more bones make contact. They are constructed to allow movement and provide mechanical support, and are classified structurally and functionally. Structural classification is determined by how the bones connected to each other, while functional classification is determined by the degree of movement between the articulating bones. In practice, there is significant overlap between the two types of classifications.
[0004] There are three structural classifications of joints, namely fibrous or immovable joints, cartilaginous joints and synovial joints. Fibrous/Immovable bones are connected by dense connective tissue, consisting mainly of collagen. The fibrous joints are further divided into three types: sutures which are found between bones of the skull; syndesmosis which are found between long bones of the body; and gomphosis which is a joint between the root of a tooth and the sockets in the maxilla or mandible.
[0005] Cartilaginous bones are connected entirely by cartilage (also known as “synchondroses”). Cartilaginous joints allow more movement between bones than a fibrous joint but less than the highly mobile synovial joint. Synovial joints have a space between the articulating bones for synovial fluid. This classification contains joints that are the most mobile of the three, and includes the knee and shoulder. These are further classified into ball and socket joints, condyloid joints, saddle joints, hinge joints, pivot joints, and gliding joints.
[0006] Joints can also be classified functionally, by the degree of mobility they allow. Synarthrosis joints permit little or no mobility. They can be categorized by how the two bones are joined together. That is, synchrondoses are joints where the two bones are connected by a piece of cartilage. Synostoses are where two bones that are initially separated eventually fuse together as a child approaches adulthood. By contrast, amphiarthrosis joints permit slight mobility. The two bone surfaces at the joint are both covered in hyaline cartilage and joined by strands of fibrocartilage. Most amphiarthrosis joints are cartilaginous.
[0007] Finally, diarthrosis joints permit a variety of movements (e.g. flexion, adduction, and pronation). Only synovial joints are diarthrodial and they can be divided into six classes: 1. ball and socket—such as the shoulder or the hip and femur; 2. Hinge—such as the elbow; 3. Pivot—such as the radius and ulna; 4. condyloidal (or ellipsoidal)—such as the wrist between radius and carps, or knee; 5. Saddle—such as the joint between carpal thumbs and metacarpals; and 6. Gliding—such as between the carpals.
[0008] Synovial joints (or diarthroses, or diarthroidal joints) are the most common and most movable type of joints in the body. As with all other joints in the body, synovial joints achieve movement at the point of contact of the articulating bones. Structural and functional differences distinguish the synovial joints from the two other types of joints in the body, with the main structural difference being the existence of a cavity between the articulating bones and the occupation of a fluid in that cavity which aids movement. The whole of a diarthrosis is contained by a ligamentous sac, the joint capsule or articular capsule. The surfaces of the two bones at the joint are covered in cartilage. The thickness of the cartilage varies with each joint, and sometimes may be of uneven thickness. Articular cartilage is multi-layered. A thin superficial layer provides a smooth surface for the two bones to slide against each other. Of all the layers, it has the highest concentration of collagen and the lowest concentration of proteoglycans, making it very resistant to shear stresses. Deeper than that is an intermediate layer, which is mechanically designed to absorb shocks and distribute the load efficiently. The deepest layer is highly calcified, and anchors the articular cartilage to the bone. In joints where the two surfaces do not fit snugly together, a meniscus or multiple folds of fibro-cartilage within the joint correct the fit, ensuring stability and the optimal distribution of load forces. The synovium is a membrane that covers all the non-cartilaginous surfaces within the joint capsule. It secretes synovial fluid into the joint, which nourishes and lubricates the articular cartilage. The synovium is separated from the capsule by a layer of cellular tissue that contains blood vessels and nerves.
[0009] Various maladies can affect the joints, one of which is arthritis. Arthritis is a group of conditions where there is damage caused to the joints of the body. Arthritis is the leading cause of disability in people over the age of 65.
[0010] There are many forms of arthritis, each of which has a different cause. Rheumatoid arthritis and psoriatic arthritis are autoimmune diseases in which the body is attacking itself. Septic arthritis is caused by joint infection. Gouty arthritis is caused by deposition of uric acid crystals in the joint that results in subsequent inflammation. The most common form of arthritis, osteoarthritis is also known as degenerative joint disease and occurs following trauma to the joint, following an infection of the joint or simply as a result of aging.
[0011] Unfortunately, all arthritides feature pain. Patterns of pain differ among the arthritides and the location. Rheumatoid arthritis is generally worse in the morning; in the early stages, patients often do not have symptoms following their morning shower.
[0012] Maladies that can affect the knee joint specifically include patellar or kneecap pain, misalignment or dislocation. Pain can exist when there is an excess of force contact between the patella and femur. This can be due to misalignment associated arthritis or anatomical conditions specific to an individual. Kneecap dislocation occurs when the triangle-shaped patellar bone covering the knee moves or slides out of place. This problem usually occurs toward the outside of the leg and can be the result of patella misalignment due to patient specific anatomy or osteoarthritis, or from trauma.
[0013] The patella rests in the patellofemoral groove, a cavity located on the knee between the distal femur and the tibia. The sides of the patella attach to certain ligaments and tendons to stabilize and support it. The upper border of the patella attaches to the common tendon of the quadriceps muscles. The side or medial borders of the patella are attached to the vastus medialis muscle, and the lower border of the patella is connected by the patellar ligament to the tibial tuberosity. The main ligament stabilizer, the patellofemoral ligament, rests directly over the femur and the patella while the lateral and medial collateral ligaments acts as the secondary ligament stabilizers from either side of the patella.
[0014] Arthritis of the patella is one of the many causes of knee pain. Patella femoral arthritis, is identified when loss of cartilage behind the patella leads to pain in the knee. The pain typically worsens when a patient walks hills, goes up or down stairs, or does deep knee flexion. Arthritis of the patella can result from an injury to the knee joint, ordinary wear and tear, or most commonly the improper tracking of the patella on the femur when the patella does not line up properly.
[0015] Non-surgical treatments for patella femoral arthritis include exercises, anti-inflammatory drugs, weight loss, pain medication and cortisone shots to help lessen the pain. External braces or taping to improve patella tracking can also be used. However, if sufficient bone loss occurs, surgery may be necessary.
[0016] Surgical options include cartilage shaving, cartilage excision, drilling into subchondral bone to induce regeneration or a lateral release where a tendon is cut to help align the knee. Other surgical options include a tibial tuberosity osteotomy, partial knee replacement and a total knee replacement, or removal of the patella entirely.
[0017] In a tibia tuberosity osteotomy, the bump on which your patellar tendon attaches (tibial tuberosity) is moved surgically by cutting the bone and adding plates and/or pins. The tibial tuberosity is moved up, down, left or right depending on the location of the damaged cartilage to move the load on the cartilage to a part of the knee that is still healthy—assuming there is such an area.
[0018] In a patellectomy the patella is removed outright. Sometimes this works, but sometimes removing the patella may hasten the onset of arthritis in the rest of the knee. A patella replacement may also be performed where part or all of the patella is replaced with an implant.
[0019] Recently, less conventional approaches to treating the patella have been proposed. In one approach, a patellar implant is placed below a patellar tendon to elevate or tilt the patellar tendon. This consequently may alter patellar tracking and decrease forces on the patella to thereby alleviate pain caused by the patella contacting the femur or tibia or by decreasing force loads across the patella-femoral joint.
[0020] In a related approach, improper force distributions associated with the patella are addressed by displacing tissues in order to realign force vectors and alter movement across loading the knee joint. Here, again, an objective is to lessen the force with which the patella is pressed against the femur during the gait cycle.
[0021] Sufficient attention does not appear to have been given in prior patella treatment approaches, however, to treatment of the knee joint throughout its full range of motion. There is also a need for avoiding negative remodeling of the patellar ligament as well as approaches to maintain a desired alignment of an implant and target tissue.
[0022] Therefore, what is needed and heretofore lacking in prior attempts to treat joint pain associated with patella misalignment or dislocation is an implantation method and implant device which addresses full range of joint movement, and which maintains desired structural integrity of anatomy forming the knee joint.
[0023] The present disclosure addresses these and other needs.
SUMMARY
[0024] Briefly and in general terms, the present disclosure is directed towards treating joint structures. In one aspect, there are disclosed approaches to redistributing forces of the patella to alleviate pain or to address misalignment.
[0025] In one particular embodiment, there is provided an implant which is contoured to receive the patellar tendon. The contour of the implant is configured to define structure preventing the patellar tendon from disengaging from the implant during a full range of motion of a knee joint. The implant is also contoured to avoid negative remodeling of the tissue of the knee.
[0026] In one embodiment, an implant for decreasing pain caused by misalignment of bones at a joint includes an implant body configured to be implanted beneath a tendon. The implant has a smooth upper surface for allowing a tendon to slide over the implant body during articulation of the joint and a hook shaped portion configured to receive at least a portion of the tendon within an overhang of the hook to alter the tracking of the bones of the joint and alleviate pain associated with misalignment of the bones of the joint.
[0027] In one embodiment of a method for treating a knee joint suffering from pain, the method includes the steps of inserting an implant below a patellar tendon; and configuring the implant so that it engages the patellar tendon throughout a full range of motion of the knee joint and so as to cause tension redistribution and contact force manipulation to alleviate pain.
[0028] In another embodiment of a method for treating a knee joint suffering from pain, the method includes the steps of inserting an implant below a quadriceps muscle or quadriceps tendon; fixing the implant to the femur; configuring the implant so that it engages the quadriceps muscle or quadriceps tendon throughout a range of motion of the knee joint; and reducing compressive loads between the patella and femur with the implant.
[0029] In another embodiment of a method for decreasing a force applied between two bones of a joint, the method includes the steps of affixing an implant to a tendon at a location between the tendon and a bone at a location proximate a the joint; allowing movement of the tendon and implant over the bone during articulation of the joint; and decreasing compressive loads between the two bones of the joint with the implant.
[0030] The implant can embody a fluid filled bladder which self-contours to tissues. In one aspect, the implant can be adjustable through the movement, addition or removal of fluid. Various embodiments are contemplated to treat patellar misalignment and to inhibit dislocation, as well as to absorb loads applied by the patella upon adjacent anatomy.
[0031] In a specific approach, an implant can include a two stage bladder having a main chamber for positioning under a ligament and a secondary chamber in communication with the main chamber. A valve can further be provided between the main and secondary chambers. During gait, fluid remains in the main chamber and performs ligament tensioning. During rest periods and when the limb is straight, fluid passes to the secondary chamber relieving tension on the ligament. This prevents negative remodeling or stretching of the ligament, as the same causes such therapy to become less effective over time.
[0032] An implant can include a chamber that is fluid or gas filled to provide a compliant bolster and lengthening effect to increase a moment arm of the bolstered tendon or muscle. The chamber and bladder can be inflated or expanded over time to provide an increasing size or stiffness structure, or deflated or contracted to provide an opposite effect. A valve or injection port can be utilized for this functionality.
[0033] The implant can further be configured such that when a leg is in extension, there is no force or little force in a first chamber of the implant. An elasticity of a second chamber is selected to cause fluid to flow into the first chamber. During gait, a valve between the chambers retains fluid within the first chamber. When at rest, with the joint in flexion the patella tendon presses fluid from the first chamber into the second chamber.
[0034] In yet another approach, an implant is provided to treat a joint and functions to redistribute forces of a patella. The implant includes structure accomplishing attachment of the implant to the patella tendon. This implant can be a single spacer or can include one or more chambers that contain fluid or gas. Such an implant thus remains in place during a full range of motion of a knee joint.
[0035] Other features and advantages of the present disclosure will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0036] FIG. 1 is a front view, depicting an implant attached to members defining a joint according to an embodiment of the present disclosure;
[0037] FIG. 2 is a cross-sectional view, depicting the structure of FIG. 1 taken along line 2 - 2 ;
[0038] FIG. 3 is a perspective view, depicting the implant of FIG. 1 ;
[0039] FIGS. 4A and 4B are side views, depicting a knee joint with and without tibial and femur implants;
[0040] FIGS. 5A and 5B are side views, depicting the knee joint and implants of FIGS. 4A and 4B with the joint flexed to about 30 degrees;
[0041] FIGS. 6A and 6B are side views, depicting the knee joint and implants of FIGS. 4A and 4B with the joint flexed to about 75 degrees;
[0042] FIGS. 7A , 7 B and 7 C are front views, depicting implants attached to members of a joint with a tibial implant only, a femoral implant only and both tibial and femoral implants according to an alternative example embodiments of the present disclosure;
[0043] FIGS. 8A-8E are front views, depicting implants having different shapes attached to a bone of a joint according to an alternative example embodiments of the present disclosure;
[0044] FIGS. 9A-9D are top views of implants having different shapes according to alternative embodiments of the present disclosure;
[0045] FIGS. 10A-10C are top views of implants having different inclinations of the superior surface according to alternative embodiments of the present disclosure;
[0046] FIGS. 11A-11C are top views of implants having different heights and different shapes according to alternative embodiments of the present disclosure;
[0047] FIGS. 12A and 12B are side views, depicting the knee joint and implants having different extensions with respect to the joint surfaces of FIGS. 8B and 8C ;
[0048] FIG. 13 is a front view, depicting an implant attached to members defining a joint according to alternative example embodiment of the present disclosure;
[0049] FIG. 14 is a cross-sectional view, depicting the structure of FIG. 1 taken along lines 5 - 5 ;
[0050] FIG. 15 is yet another front view, depicting an implant attached to members defining a joint according to alternative embodiments of the present disclosure;
[0051] FIG. 16 is a cross-sectional view, depicting the structure of FIG. 1 taken along lines 7 - 7 ;
[0052] FIG. 17 is a front perspective view depicting an implant with a roller according to an alternative embodiment of the present disclosure;
[0053] FIG. 18 is a side cross-sectional view of the implant of FIG. 17 with the knee joint at full extension;
[0054] FIG. 19 is a side cross-sectional view of the implant of FIG. 17 with the knee joint in flexion;
[0055] FIG. 20 is cross-sectional view of the implant of FIG. 17 taken along an axis of the roller;
[0056] FIG. 21 is a side view, depicting an implant according to alternative embodiments of the present disclosure;
[0057] FIGS. 22 and 23 are perspective views, depicting the implant of FIG. 21 ;
[0058] FIG. 24 is a front view, depicting an implant placed at a joint according to an alternative embodiment of the present disclosure;
[0059] FIG. 25 is a front view, depicting a an implant placed at a joint according to an alternative embodiment of the present disclosure; and
[0060] FIG. 26 is a cross-sectional view of an implant according to an alternative embodiment of the present disclosure.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0061] Referring now to the drawings, which are provided by way of example and not limitation, the present disclosure is directed towards apparatus and methods for treating a joint, and in particular, for treating a knee joint and for relieving pain caused by conditions involving the patella. Patella femoral osteoarthritis can be due to natural anatomy misalignment or can be a function of an earlier injury. Significant pain can be associated with these patellar conditions and can be a direct result of excessive forces being generated between the patella and adjacent anatomy. In particular, pain results when there are undesirable force contacts between the patella and the femur. The present disclosure is directed at alleviating pain by redirecting or absorbing excess forces without permanently remodeling tissues critical to the functioning of the knee joint.
[0062] As shown in FIGS. 1-3 , one approach to treating conditions involving a patella 90 can include the placement of an implant 100 at the knee joint 102 . The implant 100 can be generally U-shaped and can include terminal ends 104 configured to be affixed to body anatomy. In one approach, the terminal ends 104 include through holes 106 sized and shaped to receive bone screws 108 or other affixation structure. In this way, the implant 100 can be attached directly to tibia 112 of the knee joint 102 . Although the implant 100 is shown attached to the tibia 112 , it can also be affixed to the femur 110 as will be discussed further below.
[0063] Although the present apparatus and method are described particularly for reducing pain of patellar chondromalacia or osteoarthritis due to damaged cartilage on the surfaces of the patella and the trochlear groove of the femur, embodiments of the disclosure can be used to relieve the loads on other joints in a similar manner. By changing the direction and position of tendons and muscles that exert forces on joints, the implants function as a tissue elevator to reduce compressive loads on joint surfaces.
[0064] As shown in FIG. 1 , the implant 100 is affixed to the tibia 112 such that a midsection 120 of the implant 100 is configured under the patellar tendon 130 . The terminal ends 104 of the implant 100 are shown directed away from the knee joint 102 but can alternatively be pointing toward the knee joint 102 or wrapping around the tibia 112 .
[0065] The implant 100 is further contoured to define a low profile attachment structure. It is thus contemplated that a lower surface 140 of the implant 100 be curved to mimic the shape of the structure to which the implant engages, such as the tibia 112 , or femur 110 . An upper surface 142 is also contoured so as to fit nicely with the knee anatomy and may include a lubricious coating or material permitting relative motion between the implant and knee anatomy. The implant 100 may be provided in different sizes having different heights of the midsection 120 to allow a selection of different patellar tendon force reduction heights.
[0066] Once an implant 100 of a selected height is inserted beneath the patellar tendon 130 the effective angle of action of the patellar tendon on the patella 90 is modified reducing the force with which the patellar tendon presses the patella against the femur.
[0067] The upper surface 142 of the implant 100 , as shown in FIG. 2 , further includes a recess 144 designed to receive the patellar tendon 130 . The recess 144 defines a trough through which the patella tendon 130 can be translated throughout a full range of articulation and valgus and varus motion or other rotation or movement of the knee joint. Thus, a portion of the patellar tendon 130 remains within the recess 144 throughout gait as well as when the knee joint 102 is in complete flexion or extension, and all angles therebetween, and when the knee joint is loaded and unloaded. Without the recess 144 or other structure for guiding the tendon over the implant 100 , the tendon can slide off of the implant during a portion of the motion of the joint. In addition to guiding the tendon 130 over the implant 100 in the ordinary natural path of the tendon, the implant may also be arranged to alter the path of the tendon and thereby correct improper tracking of the patella over the femur. For example, where the patella 90 is shifted medially and this shift is causing wear and associated pain in the joint, the implant 100 can shift the patellar tendon laterally to reorient the tracking of the patella while also reducing the load on the patella by changing the angle of action of the patellar tendon. In the case of redirecting the trajectory of the patellar tendon, the recess 144 in the implant 100 can be modified to have more pronounced edges to achieve this redirection.
[0068] FIGS. 4A and 4B illustrate a joint at extension with and without a tibial implant 100 and a femoral implant 600 secured to the tibia and femur with bone screws (not shown). The position of the tibial implant 100 beneath the patellar tendon 130 and the femoral implant 600 beneath the quadriceps muscle or quadriceps tendon 132 reduces the load on the patellar/femoral surfaces, thus reducing patellar/femoral pain. The reduction in contact between the patellar and femoral joint surfaces can be seen by comparison of FIG. 4A without implants to FIG. 4B with implants. The magnitude of reduction in contact is dependent on the implant height selected. A large implant height is shown in FIG. 4B by way of example to more clearly show the reduction in contact forces. The patella 90 need not be lifted entirely off the patella when the knee is at full extension to provide pain relief.
[0069] FIGS. 5A and 5B illustrate the reduction in load between the patella 90 and the femur 110 at about 30 degrees of flexion of the joint. As can be seen in FIG. 5B , the distal portion of the patella 90 is lifted away from the femur 110 , significantly reducing load at this portion of the joint at partial flexion.
[0070] FIGS. 6A and 6B illustrate the reduction in load between the patella 90 and the femur 110 at about 75 degrees of flexion of the joint. As can be seen in FIG. 6B , the proximal portion of the patella 90 is lifted away from the femur 110 , however the amount of load reduction my be tailored to the particular application by altering the configuration of the implants.
[0071] The patellar implants 100 , 600 can be configured to include one or more structures that only applies tension during gait, and then, during only portions of the gait cycle. Such structure can also include a load absorption component acting during such intervals. Through this approach, undesirable permanent remodeling of knee structure, and in particular unwanted lengthening of the patellar tendon, can be avoided. One way to achieve intermittent activation of the implant is to have a multi-compartment expandable implant which inflates and deflates based on joint action. These inflatable implants will be described in further detail below.
[0072] Referring now to FIGS. 7A-7C , the tibial implant 100 and femoral implant 600 can be used either alone or in combination. The implants of FIGS. 7A-7C have a C-shaped design that wraps around the bone shaft between 45 and 180 degrees of the circumference of the bone. The wrapping around of the C-shaped design allows several muscles and/or tendons to be redirected or repositioned by the implant.
[0073] FIG. 8A illustrates an I-shaped implant 610 configured to be attached to the femur 110 . At the position shown in FIG. 8A the implant 610 would reside partly beneath the patella (not shown) when the knee joint is at full extension. The I-shaped implant sits at the end of the femur 110 near the joint and elevates the quadriceps muscle and tendon.
[0074] FIGS. 8B and 8C illustrate two variations of an I-shaped implant for the tibia. The wider implant 160 extends beyond the bone contact region and the narrower implant 170 does not extend past this contact region. These implants are shown in further detail in FIGS. 12A and 12B . FIGS. 8D and 8E illustrate J-shaped implants 180 , 190 which have a single leg extending along the bone shaft for improved bone attachment. These different designs with different attachment mechanisms can provide the surgeon with options for attachment to bone with bone screw locations that avoid disruption to the ligaments, muscles and subchondral regions of the bone.
[0075] FIGS. 9A-9D illustrate different cross section profiles for the implants including those having top surfaces which are flat, saddle shaped, convex, or concave. These profiles can apply to both tibial implants 100 and femoral implants 600 . The implant of FIG. 9A has a concave lower surface 650 configured to correspond generally to the shape of the bone and a convex upper surface 652 configured to support the overlying tendon or muscles. Medial and lateral flanges 654 at the edges of the top surface help prevent the tendons or muscles from sliding off of the implant. A plurality of feet 656 on the lower surface 650 are configured to contact the bone and allow for the implant to accommodate different anatomical variations between patients. At least one foot 656 and preferably three feet extend from the implant on the bone-facing surface or bottom surface of the implant to make contact with the bone. The feet provide an offset which allows the implant to be seated on the bone surface despite slight variations in bone surface geometries between patients and despite slight variations in positioning of the implant. The feet 656 can be provided on any of the embodiments of the implants described herein and will tightly contact the bone or the periosteum when the bone screws are tightened to press the implant against the bone.
[0076] FIG. 9B has a concave lower surface 660 and a substantially flat upper surface 662 with lateral flanges 664 . Each of the implants has two or more holes for receiving bone screws. FIGS. 9C and 9D have various saddle shaped lower and upper surfaces with bone screws inserted from the proximal or distal side of the implant ( FIG. 9C ) and from the medial and lateral sides of the implant ( FIG. 9D ). The saddle top provides a stabilizing effect to keep the tendons or muscles from sliding off of the top of the implant.
[0077] The flat top cross section of the implant 100 b of FIG. 10B produces a one directional displacement of a tendon or muscle providing primarily unloading of the patella/femoral joint. The implant may also have an medial/lateral inclination as shown in the implant 100 a of FIG. 10A to both reduce the load on the joint and also to shift the load on the joint medially or laterally. The implant 100 c of FIG. 10C has a partly flat and partly angled surface which may both shift the load and reduce the load.
[0078] FIGS. 11A-11C show a series of implants of differing heights h. Implants having heights from 2 mm to 60 mm may be provided to allow the surgeon to select the implant that unloads the joint to the desired degree. FIG. 11C illustrates an offset height f provided by the feet 656 . The height f of the feet is about 2-5 mm, preferably about 3 mm.
[0079] FIG. 12A further illustrates the tibial implant 160 which has an overhang or projection 162 which extends by a distance X beyond a line formed at the bone contacting surfaces. This overhang 162 increases the effectiveness of the implant 160 at larger angles of flexion. The femoral implant 600 is also provided with an overhang 602 , however the overhang of the femoral implant does not extend beyond the joint contact surfaces. The implant 170 of FIG. 12B shows no overhang, however the implant is positioned close to or adjacent the joint contact surfaces.
[0080] Referring to FIGS. 13 and 14 , there is shown another embodiment of an implant 200 . As before, the implant can be generally U-shaped, C-shaped, I-shaped or J-shaped and includes terminal ends 204 configured to be affixed to body anatomy. Again, through holes are provided to receive affixation structure such as bone screws 108 so that the implant can be attached directly to knee anatomy. A lower surface 240 of the implant 200 be curved to mimic the shape of the structure to which the implant 200 engages, such as the tibia 112 or femur 110 . An upper surface 242 of the implant 200 is intended to be lubricous to permit relative movement with a patellar tendon 130 . Moreover, the implant 200 can be configured with its terminal ends 204 directed toward or away from the knee joint 102 and can include a midsection with a recess 244 shaped to receive the patellar tendon 130 through a full range of motion of the knee.
[0081] This embodiment of the implant further includes a fluid, gas or gel filled chamber or bladder 250 which is accessible by an injection port 252 . The chamber 250 can form an integral structure with remaining portions of the implant 200 and portions of the implant 200 can embody fiber woven reinforced fixation material to form a single bodied structure. The injection port 252 is employed to both place substances within the chamber 200 and to be accessible to alter the volume or composition of the substance before and after implantation. The injection port 252 can also be used to remove all or most fluid when implanting or removing the implant 200 or to alter the softness or rigidity of the implant. The structure defining the chamber 250 can have an elasticity greater than that chosen for the remaining portions of the implant 200 , such as for example the terminal ends 204 which are designed to have a rigidity or robustness suited for permanent attachment to knee anatomy. The materials are of course chosen to be biocompatible in any event.
[0082] The substance chosen to fill the chamber 250 is selected to cooperate with the material chosen for walls defining the chamber 250 so that desired load redirection can be effectuated. It is further contemplated to take advantage of fluid responses of the substances chosen for placement within the chamber 250 . For example, a viscous fluid or gel such as silicone hydrogel flows smoothly under low strain rates, but resists flow under high strain rates. Therefore, the fluid or gas chosen is intended to have a viscosity and the chamber walls are designed to have a flexibility to redirect load to alleviate pain. Such load redirection can be reserved to occur primarily gait, and for that matter, during only portions of gait with greater flexion angles. During joint extension, or otherwise when there is less pain due to forces associated with the patella this manipulation is reduced so that undesirable remodeling is avoided.
[0083] Thus, as the knee joint 102 articulates during gait, the patellar tendon 130 is guided through the implant recess 244 . The load redirecting chamber 250 is sized and shaped to span the recess 244 so that during certain portions of gait having medium to high flexion angles, a height of the chamber 250 is at a maximum to provide maximum load redirection and reduced load applied directly between the patella 90 and femur 110 . For example, forces between the patella 90 and the femur 110 can be reduced and angles of action of the patellar tendon 130 can be modified to thereby minimize pain.
[0084] In yet another approach ( FIGS. 15 and 16 ), the implant 300 can further include multiple chambers 350 , 352 that are in fluid communication and which are versatile in accommodating tension and contact forces. As before, a lower surface 340 of the implant 300 be curved to mimic the shape of the structure to which the implant 300 engages, such as the tibia 112 or femur 110 . An upper surface 342 of the implant 300 is intended to be lubricous to permit relative movement with a patellar tendon 130 . Moreover, the implant 300 can be configured with its terminal ends 304 directed toward or away from the knee joint 102 and can include a midsection with a recess 344 shaped to receive the patellar tendon 130 through a full range of motion of the knee.
[0085] The generally U-shaped device can be extended to provide a platform about each of the chambers 350 , 352 . Here, again, the chambers 350 , 352 are designed to receive gases or fluids which embody desirable viscosity characteristics. Additionally, the first chamber 350 is intended to be arranged to be in apposition with the patella tendon 130 and the second chamber 352 is to be positioned remote from the tendon 130 in an area where the chamber will be free to fill and empty in a relatively unobstructed manner. Also, as before, the walls defining the chambers 350 , 352 are formed from materials having an elasticity designed to achieve desired force reorientation throughout the full range of motion of the knee joint. An injection port 354 is additionally included to provide access to the second chamber 352 so that the volume or composition of the substance in the chamber can be altered.
[0086] A neck 356 joining the first 350 and second 352 chambers provides the fluid communication between the structures. A valve (not shown) can be configured in this area or the neck 356 can define a small opening. In either approach, the neck 356 can be configured to play a role in the movement of fluid from one chamber to the next. For example, when a leg of an individual is in extension, there is no force or little force on the first chamber 350 . The elasticity of the second chamber 352 is chosen to thus cause fluid to flow into the first chamber 350 . During gait, the sizing of the neck 356 is such that its flow access is limited so that there is insufficient time for fluid to pass from the first chamber 350 to the second chamber 352 . Rather, the fluid remains but flows within the first chamber 350 to thereby provide force reorientation. When seated or otherwise placing the knee joint 102 in other resting or non-gait positions, with the joint in flexion, the force of the patellar tendon 130 presses fluid out of the first chamber 350 into the second chamber 352 . As such, the first chamber 350 is reduced in size during this juncture, and the patellar tendon 130 is not subjected to the increased tension caused by the implant 300 . By not engaging in this manipulation, the patellar tendon 130 can be unloaded and remodeling thereof is avoided.
[0087] In another embodiment, the second chamber 352 can be positioned within an anatomical structure, such as a muscle, and the fluid will be forced into the first chamber 350 by activation of the muscle. Therefore, the implant 300 can be activated by muscle activation, such as during running or walking, and can remain relatively passive at other times.
[0088] FIGS. 17-20 illustrate a further embodiment of an implant 700 having a roller 710 . The implant 700 is designed to further reduce the friction between the implant and the tissue sliding over it. The roller 710 makes contact with the tendons, muscles and other tissues to reduce potential tissue irritation including tendonitis, inflammation, tendon tears and rupture. The roller 710 is supported in the implant 700 within blind bores 712 by bearing rollers 714 . Bearing rollers 714 are protected by a seal 716 in the form of O-rings, quad rings, lip seals or the like.
[0089] In a related approach, as shown in FIGS. 21-23 , an implant 400 designed to accomplish force reorientation can be affixed directly to the patellar tendon 130 . This implant 400 can further include one or more of the features described above including one or more fluid filled chambers. Further, it is again contemplated that the device be formed from biocompatible materials. This particular implant 400 further embodies a porous or mesh tendon contacting surface 402 and a lubricious bearing surface 404 for sliding contact with bone. The porous mesh surface 402 supports ligament ingrowth and aids in attachment to the patellar tendon 130 . The lubricious bearing surface 404 slides along knee anatomy during articulation. Through holes 406 are further provided and sized and shaped to receive fastening structures 410 for assuring a strong affixation to the patellar tendon 130 . In this way, relative movement between the implant 400 and ligament is eliminated and the implant 400 is thus always correctly positioned to provide desired force reorientation and pain relief. Other methods for attachment of the implant 400 to the patellar tendon 130 or other tendons or muscles may also be used including known tissue ingrowth surfaces on the implant, sutures, mechanical clamping or combinations of attachment mechanisms. There is no risk of the patellar tendon remodeling around the implant 400 because the implant is connected directly to the tendon.
[0090] With reference to FIG. 24 , there is shown in yet another embodiment of an implant 500 . This implant 500 can include one or more of the above described features, such as one or more chambers, and further embodies a generally inverted J-shape. A vertically extending portion 502 of the implant 500 is provided with through holes sized and shaped to receive fastening structure such as bone screws 108 . A laterally extending portion 508 includes a recess 510 for receiving a patellar tendon 130 . Although the implant 500 is shown attached to the tibia 112 , it can also be affixed to the femur 110 as well. This approach illustrates that an asymmetric implant can be employed to accomplish desired treatment of the patella 90 . A further deviation would be to eliminate the vertically extending portion 502 and to include affixation structure within the recess 510 . The implant 500 also has a trough or recess as in the implant shown in FIG. 2 to guide in tracking the patellar tendon over the implant in a desired trajectory.
[0091] FIG. 25 shows a hook shaped implant 500 a which functions to both elevate the tendon 130 and to alter the tracking of the patella 90 . A hook 520 can move the patellar tendon and consequently the patella itself laterally, such as toward the lateral side of the knee when the patella pain is caused by improperly tracking to far to the medial side. The hook 520 is sized to receive at least a portion the tendon underneath the hooked portion of the implant.
[0092] FIG. 26 illustrates a bridge shaped implant 800 which lifts the patellar tendon 130 in a manner similar to the lift implants shown herein, but lifts from the superior surface of the patellar tendon rather than from the inferior surface. The bridge can be attached to the patellar tendon 130 by sutures, mechanically clamped, tissue ingrowth or a combination thereof.
[0093] The various embodiments of the implants describe herein may be made from a wide range of materials. According to one embodiment, the implants are made from metals, metal alloys, or ceramics such as, but not limited to, Titanium, stainless steel, Cobalt Chrome or combinations thereof. Alternatively, the implants are made from thermo-plastic materials such as, but not limited to, high performance polyketones including polyetheretherketone (PEEK), ultra-high molecular weight polyethylene (UHMWPE), PyroCarbon or a combination of thermo-plastic and other materials. Various embodiments of the implants are relatively rigid structures.
[0094] Conventional approaches to inserting the above-described implants within knee anatomy are contemplated. Arthroscopic approaches can be employed along with fluoroscopy or other imaging techniques to properly position the treatment devices. Prior to implantation, the anatomy of the patient's knee is accessed to determine a best course of treatment, and to identify a configuration of implant which best suits the patient's specific condition. The knee is rotated and turned through its full range of motion to identify proper implantation sites and to access the best manner for redistributing tensions and contact forces, with the objective of reducing pain. Further, the implant is configured in its most compressed configuration for implantation and then reconfigured to function in a treatment capacity. Subsequent to implantation, the implant can be reconfigured to present an altered profile to achieve optimum results.
[0095] The foregoing therefore provides an implant embodying a compliant bolster and lengthening affect to increase a moment arm of the bolstered patellar tendon for the purpose of relieving pain or other symptoms involving the patella. The size or stiffness of the implant can be altered to achieve the desired bolstering or manipulation of tension and contact forces.
[0096] Thus, it will be apparent from the foregoing that, while particular forms of the apparatus and method have been illustrated and described, various modifications can be made without parting from the spirit and scope of the disclosure. In particular, one or more features of one specific approach can be incorporated into another approach. Additionally, the present disclosure can be made to be applicable to other medical conditions.
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Implant apparatus and methods directed toward treating conditions involving the knee joint and the patella specifically are disclosed. Full range of motion of the knee joint and tissue integrity are maintained in treatment approaches involving implanting a joint surface load reducing implant proximate the joint to change the direction of the tendons or muscles exerting forces on the joints.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates in general to control systems for an automotive automatic transmission, and more particularly to control systems of a type which controls the transmission in accordance with engine load parameters. More specifically, the present invention is concerned with a control system for an automatic transmission associated with an internal combustion engine which is operatble on a mixed fuel including gasoline and alcohol.
2. Description of the Prior Art
Hitherto, various types of control systems for an automotive automatic transmission have been proposed and put into practical use.
One of them is a type shown in Japanese Patent First Provisional Publication 61-257332. In this control system, a throttle valve angle and a vehicle speed, which can be typical parameters for representing the engine load, are used for making a gear change data map. Under running of the vehicle, an appropriate gear position is looked up from the data map and a suitable gear change is carried out providing the transmission with the appropriate gear position.
Some of the conventional control systems are of a type in which the line pressure (viz., the oil pressure produced by an oil pump) of the transmission is controlled in accordance with the throttle valve angle.
In general, as the parameters for the engine load, the amount of air fed to the engine is used in addition to the throttle valve angle and the vehicle speed.
Nowadays, as a substitute for gasoline, alcohol, such as methanol or the like, has been introduced as fuel for automotive engines as is discussed in, for example, Japanese Patent First Provisional Publication 56-98540. The engine disclosed by this publication can be operated on either gasoline, alcohol or mixture of them. That is, an alcohol sensor is used for detecting the alcohol concentration in fuel, and the amount of fuel fed to the engine is controlled or corrected in accordance with the detected alcohol concentration. However, if an engine of the type disclosed by 56-98540 publication and an automatic transmission of the type disclosed by 61-257332 publication are simply combined, the following undesired phenomena may occur.
As is seen from the graph of FIG. 4, the engine torque obtained under the same rotation speed is different between gasoline and alcohol. Thus, if the engine load parameters given by the engine of 56-98540 publication are simply used for controlling the transmission of 61-257332 publication, they fail to accurately control the transmission in accordance with the engine torque. That is, if the line pressure is controlled by the throttle valve angle, the intake air amount and the vehicle speed, which are parameters for representing the engine load, a concentration change of alcohol in fuel tends to cause a marked shift shock as well as a marked slippage of friction elements of the transmission, which deteriorate drivability of the vehicle as well as fuel consumption of the same.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a control system for an automotive automatic transmission, which is free of the above-mentioned drawbacks.
According to the present invention, there is provided an automatic transmission control system for use in a motor vehicle having an internal combustion engine and an automatic transmission associated with the engine, the engine being operable on a fuel which is a mixture of gasoline and alcohol. The control system comprises an alcohol sensor for sensing the alcohol concentration in the fuel; first means for deriving an engine load parameter which represents the load applied to the engine; second means for correcting the engine load parameter with reference to the alcohol concentration sensed by the alcohol sensor; and third means for controlling a line pressure of the transmission in accordance with the corrected engine load parameter.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects and advantages of the present invention will become apparent from the following description when taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a block diagram showing the concept of the present invention;
FIG. 2 is a schematic diagram showing the present invention;
FIG. 3 is a flowchart showing the sequence of operation conducted in a control system of the present invention; and
FIG. 4 is a graph showing torque characteristics of an internal combustion engine operated on gasoline and alcohol.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 2, there is schematically shown a control system for an automatic transmission 2, according to the present invention. Designated by numeral 1 is an internal combustion engine to which the transmission 2 is connected. As is apparent as the description proceeds, the engine 1 can be operated on a fuel which is a mixture of gasoline and alcohol.
The transmission 2 comprises generally a torque converter 3 which converts the torque of the engine 1, a speed change mechanism 4 to which the converted torque is applied from the torque converter 3, hydraulically operated actuators (not shown) for actuating various friction elements of the speed change mechanism 4 and a hydraulic circuit 5 which controls the actuators in accordance with instructions applied thereto from a control unit 6.
The control unit 6 is constructed of a microcomputer, into which information signals from various sensors are fed through a suitable interface.
One of the sensors is a hot wire type air flow meter 8 located in an air intake passage of the engine 1 at a position upstream of a throttle valve 7. The air flow meter 8 detects the amount "Q" of air fed to the engine 1.
Designated by numeral 9 is a crankangle sensor which issues a reference pulse signal each time the engine crank passes a given angular position. By measuring the period of the reference pulse, an engine speed "N" is derived.
Designated by numeral 11 is a vehicle speed sensor which, by measuring the rotation speed of an output shaft 10 of the transmission 2, outputs a signal representing a vehicle speed "VSP".
Designated by numeral 12 is an alcohol sensor which senses the alcohol concentration in a mixed fuel, that is, a mixture of gasoline and alcohol. The alcohol sensor 12 may be of a capacitance type which practically uses the phenomenon in which the capacitance of the mixed fuel changes as the concentration of alcohol in the fuel changes. In accordance with the information signal issued from the alcohol sensor 12, the fuel amount fed to the engine 1 is electronically controlled.
As will be described in detail hereinafter, the information signal from the alcohol sensor 12 is also used for controlling the automatic transmission 2.
The computer of the control unit 6 includes a first CPU (viz., central processing unit) for controlling the engine 1 and a second CPU for controlling the transmission 2. The computer has a dual port random access memory "RAM" operatively connected to both the first and second CPUs. Thus, instruction data produced by both the CPUs can be commonly used for controlling both the engine 1 and the transmission 2.
The second CPU for the transmission 2 controls through the hydraulic circuit 5 the transmission 2 in such a manner that in "D(drive)-range", the transmission 2 is automatically shifted up or down to take first, second, third or fourth gear position in accordance with the information signals issued from the sensors 8, 9, 11 and 12 with reference to the memorized gear change data map.
As will be understood from the following, the second CPU for the transmission 2 controls also the line pressure of the transmission 2 in accordance with the engine torque.
FIG. 3 is a flowchart showing operation steps conducted in the control unit 6 for achieving the line pressure control. At step 1 (viz., S1), an intake air amount "QF" corresponding to a friction loss of the engine 1 is looked up from a memorized data map which shows the relationship between the engine rotation speed "N" and the intake air amount "QF".
At step 2, the following subtraction is carried out to obtain a difference "Qf" which represents a corrected intake air amount.
Qf=Q-QF (1)
wherein:
Q: intake air amount detected by air flow meter 8.
At step 3, the following division is carried out to obtain a quotient "TQ".
TQ=Qf/N (2)
The quotient "TQ" is set as a parameter "TQ1" which represents the engine load.
At step 4, a correction factor "COMET" for correcting the engine load parameter "TQ1" is looked up from a given data map which shows the relationship between the alcohol concentration detected by the alcohol sensor 12 and the COMET".
In the present invention, when the alcohol concentration is zero, that is, when the fuel contains only gasoline, the correction for the engine load parameter "TQ1" is not effected. That is, in such case, the correction factor "COMET" is set to 1.0, and as is seen from the data map of step 4, the correction factor "COMET" is gradually increased with increase of the alcohol concentration. This is because the engine torque given at the same intake air amount increases as the alcohol concentration in fuel increases. This will be understood from the graph of FIG. 4.
At step 5, the following multiplication is carried out to obtain a finally corrected parameter "TQSEN" which correctly represents the engine load.
TQSEN=TQ×COMET (3)
Since the engine torque is forced to change when the alcohol concentration in fuel changes, the parameter "TQ1" can not accurately represent the engine torque. However, by correcting the parameter "TQ1" with the correction factor "COMET" using the equation of (3), the engine load is accurately represented by the "TQSEN".
At step 6, a target line pressure is looked up from a given data map which shows the relationship between the "TQSEN" and the target line pressure. In accordance with the target line pressure thus obtained, the control unit 6 controls the line pressure of the transmission 2 through the hydraulic circuit 5.
As is known to those skilled in the art, when the torque applied to the transmission 2 is increased, it is needed to increase the line pressure. In the present invention, this need is attained by the finally corrected parameter "TQSEN" which depends on the alcohol concentration in fuel. Thus, marked slippage of friction elements of the transmission and marked shift shock due to short line pressure are suppressed or at least minimized.
In the present invention, the following modifications are also possible.
If desired, the engine load parameter "TQSEN" may be used for determining a target gear position of the transmission. That is, in this modification, a gear change pattern data map is previously memorized by using both the above-mentioned corrected engine load parameter "TQSEN" and the vehicle speed "VSP" detected by the vehicle speed sensor 11, and the target shift position is looked up from this data map. Thus, in this modification, a desired shift position is obtained by the transmission in accordance with the engine torque which depends on the alcohol concentration in fuel.
Although, in the above-mentioned embodiment, the air flow meter 8 is used for obtaining the parameter "TQ", such parameter may be obtained by using a throttle valve angle sensor.
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A control system for automatic transmission is provided in a motor vehicle having an internal combustion engine and an automatic transmission associated with the engine. The engine is operable on a fuel which is a mixture of gasoline and alcohol. The control system comprises an alcohol sensor for sensing the alcohol concentration in the fuel; a first device for deriving an engine load parameter which represents the load applied to the engine; a second device for correcting the engine load parameter with reference to the alcohol concentration sensed by the alcohol sensor; and a third device for controlling a line pressure of the transmission in accordance with the corrected engine load parameter.
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FIELD OF THE INVENTION
[0001] The invention concerns a baler with a parallelepiped or slab-shaped baling chamber and a baling piston enclosed in it that is free to move.
BACKGROUND OF THE INVENTION
[0002] The prospectus “GREENLAND Large Baler Vario Industry”, no publication date, discloses a large baler with a baling channel that can be adjusted in 5 cm. steps between a height of 0.65 m. and 0.8 m. In this way bales of different dimensions can be produced.
[0003] The problem underlying the invention is seen in the fact that the conversion to a different channel cross section requires approximately one day. Furthermore at present a greater range of channel cross sections is being demanded.
SUMMARY OF THE INVENTION
[0004] According to the present invention, there is provided a baler for making parallelepiped bales and having an easily adjustable baling chamber.
[0005] A broad object of the invention is to provide a baler having a baling chamber for forming parallelepiped bales and the cross section of which can be easily changed as desired and made to conform to the size, particularly the height, of the transport vehicle available for the particular field.
[0006] Another object of the invention is to provide an adjustable baling chamber, as set forth in the preceding object, together with an adjustable needle arrangement whereby the needles and with them the entire tying arrangement is located on a movable upper chamber housing part, so that the spacial arrangement of the needles relative to the tying arrangement does not change when this part is repositioned, so that a secure engagement of the needle points in the knot tying device is assured.
[0007] Another object of the invention is to provide an adjustable baling chamber, as set forth in the foregoing objects, and together with this to incorporate structure providing the ability to reposition a drive, for example, a flywheel drive with a crank arm or a hydraulic motor together with the repositioning of the upper chamber part such that the force of the driver is always applied to the center of the baling piston so that it occupies a secure and centered end position.
[0008] A more specific object is to provide spindles, spreader linkages and the like as possible actuators for the repositioning of the upper chamber part, or more advantageously to use of motors, particularly remote controlled motors since these are simple devices which can transmit large forces.
[0009] Another specific object is to construct the side surfaces of the baling channel such as to cover the entire height, so no crop to be baled can escape and cause jams. If the side walls extend in one-piece configuration from above or below, a smooth surface results with low frictional resistance; if upper and lower walls are provided, that overlap vertically, then the entire side walls do not project either at the top or at the bottom. Depending on the dimensions selected such a large vertical repositioning movement can be attained so that an access from the outside into the baling chamber is possible.
[0010] A light-weight configuration of the baler can be attained by arranging the large components, particularly the cover or top and the bottom, as well as the side walls of the baling chamber, as a light-weight design so that the forces are absorbed by a few massive components, for example, the repositioning arrangement, which surround the baling chamber and carry and reposition the chamber top and portions of the side walls.
[0011] Another object of the invention is to configure an upper region of the baling piston as a collection of ribs such that a generally closed baling surface of the baling piston results, which leads to a uniform compression. The baling piston can be subdivided actually, not only conceptually, into an upper and a lower part. Slots in the chamber top or cover, for example, as an alternative to a large opening have the advantage that the ribs can extend through them and that the cover encloses the baling chamber at the sides as much as possible. The change of the cross section of the baling chamber can then be performed by lowering or raising the cover and letting the ribs extend to a greater or lesser distance through the slots.
[0012] The actual subdivision of the baling piston into two parts leads to a simplification of the manufacturing process.
[0013] The covering of the baling chamber at its sides does not stand in the way of a repositioning in height if the side walls extend into slots in the moving or the stationary part of the housing and are able to penetrate more or less deeply into the slots.
[0014] The accommodation of the position of the needles to the knot tying devices can be accomplished easily if openings are provided in the base body through which the needle support arms and journals connected to the movable part of the repositioning arrangement can extend.
[0015] If instead of a change in the height of the bale, its width can be varied, not only the height of the platform of the transport vehicle can be accommodated, but its length and width can be accommodated as well and an optimum loading can be achieved. In principle the repositioning arrangement would only need to be rotated through 90° and extended in the horizontal direction. The piston ribs would then not be extended vertically, but horizontally. If the supply channel is made to accommodate the cross section or is equipped with guide vanes a uniform supply across the entire width is assured.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] [0016]FIG. 1 is a schematic left side elevational view of a baler having a baling chamber constructed for adjustment in accordance with the invention.
[0017] [0017]FIG. 2 is a schematic left side view of a baling chamber of the baler shown in a maximum height condition.
[0018] [0018]FIG. 3 is a schematic left side view like that of FIG. 2, but showing the baling chamber adjusted to a minimum height condition.
[0019] [0019]FIG. 4 is a vertical sectional view taken along line 4 - 4 of FIG. 1, and showing the baling chamber in its maximum height condition.
[0020] [0020]FIG. 5 is a view similar to that of FIG. 4, but showing the baling chamber in its minimum height condition.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0021] [0021]FIG. 1 shows a baler 10 in the form of a large baler for the production of parallelepiped or slab-shaped bales, that includes a frame 12 supported on the ground by support wheels 14 in a tandem arrangement. A towbar or tongue 16 is connected to, and projects forwardly from, a front end of the frame 12 and is configured in such a way that it can be connected to a towing vehicle, such as an agricultural tractor, not shown, which is equipped with a power take-off shaft in order to deliver power to drive various components of the baler 10 . A baling chamber 18 or an enclosure of rectangular cross section is formed partially by an upper housing part 20 and a lower housing part 22 , where the lower housing part 22 is equipped with a crop inlet 24 which is connected to a curved supply channel or duct 26 , that is used as a pre-compression chamber, as is described in the following. A take-up arrangement 28 in the form of a pick-up together with a center-feed screw conveyor is arranged ahead of the supply channel 26 , in order to take up a swath or windrow of crop from the ground and to deliver it to a compression fork 30 . The fork 30 is used to compress crop in the supply channel 26 , until a load of pre-selected density has collected downstream of fingers 32 of a retaining arrangement 34 mounted so as to pivot between a retaining position in which the fingers 32 project into the supply channel 26 in the vicinity of the crop inlet 24 , and a supply position, in which the fingers 32 are retracted from the supply channel 26 , as shown, in order to make it possible for a load of crop to be forced into the baling chamber 18 through a crop inlet 24 by means of a loading fork assembly 36 . At a forward lower position of the supply channel 26 , a spring-loaded flap 38 is mounted, free to pivot, that pivots as a function of crop contained in the supply channel 26 , until this reaches a desired density, in order to effect activation of a circuit to supply current to an electrical control circuit, not shown, which establishes corresponding drive connections which initially have the effect that the retaining arrangement 34 moves in such a way that it retracts the fingers 32 from the retaining position into the position shown in FIG. 1, and then activates the loading fork assembly 36 in such a way that thereupon the compression fork 30 is slid through the supply channel 26 and moves the load of crop into the baling chamber 18 . Once the load of crop has been forced into the baling chamber 18 , a piston mechanism 40 , that is mounted to a forward location of the frame 12 , is actuated in a controlled sequence after the loading fork assembly 36 , in order to move the crop to the rear into the baling chamber 18 , where it is compressed in a stack, as is well known in the state of the art. After the stack of compressed material has reached a predetermined length, a needle assembly 42 , which includes several separate curved needles 68 , is actuated in order to deliver binding twine to a corresponding number of knot tying devices, not shown, that operate in such a way that they lay lengths of twine about the predetermined length of the stack in order to form a bale 44 that is ready for unloading, which occurs when it is forced out of the rear end region of the baling chamber 18 by a part of a bale 46 , when its length is increased by new loads of crop being forced into the baling chamber 18 . Since the invention concerns the repositioning of the baling chamber 18 —as is explained below—the amount of the crop supplied could be made to conform to the immediate size of the baling chamber 18 .
[0022] Referring again to the piston mechanism 40 , it can be seen that the latter includes a baling piston 48 that is arranged for a back and forth movement in the baling chamber 18 between a retracted position ahead of the crop inlet 24 and an extended position beyond the crop inlet 24 (see FIG. 1). This movement of the baling piston 48 has the result that loads of harvested crop, that are introduced from the supply channel 26 into the baling chamber 18 , are compressed against a stack of harvested crop, which includes the partially formed bale 46 and/or the complete bale 44 . Furthermore the piston mechanism 40 contains a driver 50 configured as an actuating arrangement, that can be extended and retracted, which is shown here as a double-acting hydraulic cylinder-piston unit, whose cylinder end is anchored with a pin 52 , free to pivot, on the frame 12 at a point above the compression fork 30 . The piston end of the drive 50 is connected at a connecting point 54 to a device such as a pin at a location between opposite ends of a first steering arm 56 used as a crank arm, whose forward end region is connected, free to pivot, at a bearing location 58 on the frame 12 . A rear end region of the first steering arm 56 is connected at a bearing location 60 to a device such as a pin on a forward end region of a second steering arm 62 operating as a connecting rod, whose rear end region is connected at a bearing location 64 by means of a device such as a pin with the baling piston 48 . It should be noted here that the connecting pins of the bearing locations 58 and 64 are arranged along a line of centers that lies along or approximately along a longitudinal centerline of the baling chamber 18 . This has the result that the reacting force of the harvested crop that acts upon the baling piston 48 , is substantially absorbed by the driver 50 , when the first and the second steering arm 56 and 62 are located along a line, which is the case when the baling piston 48 is located in its rear end position. Furthermore it should also be noted that the two steering arms 56 and 62 could be configured in each case as a pair of steering arms spaced at a distance to each other in the transverse direction. The driver 50 would then be connected at the connecting point 54 (pin) at a point between the pair of steering arms 56 , that form the first steering arm 56 . It can therefore be recognized that the baling piston 48 forms the slider of a slider crank mechanism that includes a first steering arm 56 as the crank arm, and a second steering arm 62 and the steering arms 94 as connecting rods. Although the linkage formed by the steering arms 56 , 62 and 64 does not move beyond a dead center position, it could be characterized as a toggle link mechanism or a toggle link. Although the preferred embodiment shows a driver 50 , that is connected to the first steering arm 56 at a point between opposite ends of the first steering arm 56 , the driver could be connected at any point between the bearing location 58 and the bearing location 64 ; for example, the driver 50 could be connected to the pin 60 or at a point along the length of the second steering arm 62 , where the operation is in a better condition than that of the known arrangement, in which the actuation arrangement is connected directly to the baling piston 48 .
[0023] Further details of this baler 10 are described in EP-A2-0 940 072, whose disclosure is hereby incorporated herein. It should be noted that in place of this special drive with a hydraulic motor, a conventional crank drive can be applied equally well.
[0024] [0024]FIGS. 2 through 5 refer only to the configuration of the baling chamber 18 and the baling piston 48 that is guided in it. The uniqueness of this invention lies in the fact that the cross section, in particular the height, of the baling chamber 18 can be varied in order to produce bales 44 of differing heights and thereby also of differing mass.
[0025] For this purpose the upper part of the housing 20 is arranged so as to be repositioned in height, as will be explained below on the basis of FIGS. 4 and 5.
[0026] The upper part of the housing 20 is equipped with a cover 21 , that is configured in conventional manner as a heavy sheet metal component, that is relatively stiff in bending and preferably extends as a one-piece component over the entire length of the baling chamber 18 . On the upper side of the upper part of the housing 20 and to the rear of the supply channel 26 , a knot tying device assembly 66 is provided in known manner, into which the needles 68 of the needle assembly 42 can penetrate. Each side of the needle assembly 42 includes a needle support arm 70 , that can be pivoted in a vertical plane and moves the needles 68 through the baling chamber 18 with the twine, not shown, to the knot tying device assembly 66 , as soon as a bale 44 is to be bound. The cover 21 is carried at various points along its length by a yoke 72 , which forms a part of a repositioning arrangement 74 located at each point and that also includes a base body 76 . Slots 82 are provided in the cover 21 in the path of movement of, and extend in the direction of movement of the baling piston 48 . In order to insure that the stiffness of the cover 21 is adequate in this region, the cover 21 is configured with relatively thick walls or it could be constructed with reinforcing sheet metal components or the like.
[0027] The housing bottom 23 is formed in conventional manner from steel sheet metal that may be profiled, as shown, if necessary, and which extends over the entire length of the baling chamber 18 and is in contact, without movement, with the base body 76 of each repositioning arrangement 74 . While the cover 21 is generally closed, the bottom 23 is interrupted by the crop inlet 24 for the supply channel 26 and the inlet opening (not shown) for the needles 68 . The cover 21 and the bottom 23 extend generally parallel to each other. Nevertheless, in the rear outlet region for the bale 44 , adjustable flaps are provided, that are not shown but are well known, which give the bale 44 a certain resistance to movement.
[0028] The piston mechanism 40 includes the baling piston 48 , that can be shifted between two end positions by means of the driver 50 as is described in EP-A2-0 940 072. In the preferred embodiment, the baling piston 48 is subdivided into an upper part 78 and a lower part 80 , that are either configured separately from each other and are rigidly connected to each other or are formed as a one-piece component, as illustrated.
[0029] The upper part 78 is composed generally of transversely spaced, parallel, upright ribs 84 , that extend principally in the direction of movement of the baling piston 48 . The height of the ribs 84 is dimensioned in such a way that in every position of the cover 21 they extend through the slots 82 . The number of ribs 84 is selected in such a way that a relatively closed conveying surface of the baling piston 48 results and the spaces between the ribs 84 are relatively small. In the selected embodiment, nineteen ribs 84 are present. In other embodiments, there could be more or fewer. The width of the ribs is selected in such a way that they can be engaged in the slots 82 with relatively little play.
[0030] The lower part 80 is configured as a completely closed box. As a deviation from this configuration the lower part 80 may also be open downward and/or on the left side as seen in FIG. 1. On the side walls of the lower part 80 , journals 88 are provided with rolls 90 supported in bearings, free to rotate, on the journals, in particular several in a row at equal heights. On the side of the piston 40 facing the crop to be baled, i.e., the rear side, compression means, not shown, channels for the penetration of the needles or the like can be provided. The steering arm 62 preferably engages in a joint at the center of the lower piston part 80 . The bearing location 58 that connects the first steering arm 56 in a joint is configured to be adjustable in height as well as in the longitudinal direction of the baling chamber 18 , for example, on an inclined plane in such a way that both steering arms 56 and 62 in their extended position extend in the longitudinal center plane of the baling chamber 18 . Nevertheless, this is only one preferred embodiment, that can frequently be omitted. Depending on the configuration of the guidance of the baling piston 48 , the steering arms 56 and 62 can also engage off center of the baling chamber 18 , that is, the bearing location 58 of the steering arm 56 remains unchanged.
[0031] On each side, a side wall 96 extends between the cover 21 and the bottom 23 , which engages a slot 98 in the side legs of the yoke 72 , so as to be able to slide vertically. The side walls 96 extend, fixed rigidly or removable, to the side outside of the cover 21 and are connected to the base body 76 .
[0032] The yoke 72 is configured as an inverted “U” and manufactured from tubing material or as a weldment. Each vertical leg of the yoke 72 is provided with a slot 98 and is rigidly connected over a bridge 86 with the other vertical leg. At the lower end of each leg of the yoke 72 , a connection 104 is provided for a servo motor 106 , that will be described in greater detail below. In place of the servo motors 106 , other repositioning mechanisms could be used, for example, levers, threaded spindles etc. The cover 21 is rigidly attached to the inside of the legs of the yoke 72 .
[0033] The base body 76 is configured in the shape of a “U”, whose legs extend upward alongside the legs of the yoke 72 . Between the legs of the base body 76 , the bottom 23 is in contact with, and connected to, the base body 76 . At approximately half the height of the legs, a guide 108 , configured as a “U”-shaped rail, is attached on each side on or in the legs, which extends parallel to the bottom 23 . These guides 108 receive the rolls 90 of the lower part 80 within themselves, free to rotate. The side walls 96 extend upward erect above the guides 108 . In the upper region of the legs openings 92 are provided through which journals 94 extend that engage the needle support arm 70 on the yoke 72 , free to move. While the bottom of the base body 76 can also be formed from a tube, a rail, a weldment or the like, its legs are configured as vertical guides that contain an interior space 110 . At the bottom of each interior space 110 , a connection 104 is also provided for the other end of the servo motor 106 . In the region of the interior space 110 located above it the legs of the yoke 72 are engaged so as to slide, free to move vertically.
[0034] The servo motors 106 extend between the bottom of the interior space 110 and the lower end of the legs of the yoke 72 and are connected over each of the connections 104 to these in a positive lock. The servo motors 106 may be configured as hydraulic motors or as electric motors, which, however, may depend on the forces to be transmitted, the space available and the like. It is necessary, however, to guarantee that during a repositioning process all servo motors 106 cover exactly the same path, so that there is no warping between each of the yokes 72 . The servo motors 106 are remotely controlled, for example, from the vehicle towing the baler 10 . While in the present embodiment the servo motors 106 are assumed to be double acting hydraulic motors, in other embodiments single-acting servo motors 106 could also be used, that are again retracted downward either on the basis of spring force or the force of gravity acting on the yokes 72 .
[0035] On the basis of the above description the result is the following configuration and the following operation.
[0036] The bottom 23 and the guides 108 are inserted and fastened to the base body 76 . Following this the servo motors 106 are inserted into the interior spaces 110 , connected with the base body 76 and connected to a hydraulic system, not shown. Then the baling piston 48 with its rolls 90 is slid into the guides 108 and the steering arm 62 is connected with the baling piston 48 . Following this, the cover 21 is laid upon the baling piston 48 , so that the ribs 84 extend through the slots 82 . Subsequently, the yoke 72 is slid into the interior spaces 110 and connected to the cover 21 and the servo motors 106 . Finally the journals 94 are inserted through the openings 92 and fastened to the yoke 72 and connected to the needle support arms 70 .
[0037] According to FIGS. 2 and 4, the baling chamber 18 can be adjusted so as to occupy a maximum height condition, and, according to FIGS. 3 and 5, it can be adjusted to occupy a minimum height condition.
[0038] The further description begins with the assumption that it is desired to adjust the baling chamber from its maximum height condition, shown in FIGS. 2 and 4, to its minimum height condition, shown in FIGS. 3 and 5, this being performed as follows.
[0039] The servo motors 106 are retracted synchronously and pull the yokes 72 downward, whereby the baling chamber 18 is lowered. Simultaneously the bearing location 58 is shifted, so that the stroke of the baling piston 48 and the position of the steering arm 56 , 62 remains unchanged with respect to the baling piston 48 .
[0040] As a result of the attachment of the needle assembly 42 to the yoke 72 or the upper housing part 20 , the former also moves upward or downward and maintains the spacial relationship to the knot tying device assembly 66 .
[0041] While the present embodiment is initially based on the assumption that the upper housing part 20 is movable and the lower housing part 22 is fixed, this could also be the reverse, where then nevertheless the supply channel 26 and the components connected to it would have to be modified accordingly. Finally all side walls, the cover 21 and the bottom 23 could also be repositioned individually or in unison.
[0042] Having described the preferred embodiment, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying claims.
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A baler includes a baling chamber configured for forming parallelepiped bales. The baling chamber has a top wall that is adjustable toward and away from a bottom wall of the chamber. The top wall is provided with a plurality of transversely spaced, parallel slots extending lengthwise of the chamber. A baling piston is mounted for movement within the baling chamber and includes an upper part which is defined by a plurality of transversely spaced ribs that are respectively received in the slots in the top wall and accommodate the movement of the latter during adjustment.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This patent application is a continuation of U.S. patent application Ser. No. 12/099,653, filed Apr. 8, 2008, which claims priority to U.S. divisional patent application Ser. No. 11/121,154, filed May 4, 2005, issued as U.S. Pat. No. 7,365,180, on Apr. 29, 2008, which claims priority to U.S. Provisional Application No. 60/567,971, filed May 4, 2004, the contents of which are incorporated herein, in their entirety, by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention is generally directed to degradative enzymes and systems. In particular, the present invention is directed to plant cell wall degrading enzymes and associated proteins found in Microbulbifer degradans and systems containing such enzymes and/or proteins.
[0004] 2. Background of the Invention
[0005] Cellulases and related enzymes have been utilized in food, beer, wine, animal feeds, textile production and laundering, pulp and paper industry, and agricultural industries. Various such uses are described in the paper “Cellulases and related enzymes in biotechnology” by M.K. Bhat (Biotechnical Advances 18 (2000) 355-383), the subject matter of which is hereby incorporated by reference in its entirety.
[0006] Saccharophaagus degradans strain 2-40 (herein referred to as “ S. degradans 2-40” or “2-40”) is a representative of an emerging group of marine bacteria that degrade complex polysaccharides (CP). S. degradans has been deposited at the American Type Culture Collection and bears accession number ATCC 43961 . S. degradans 2-40, formerly known and referred to synonomously herein as Microbulbifer degradans strain 2-40 (“ M. degradans 2-40”), is a marine y-proteobacterium that was isolated from decaying Sparina altemiflora , a salt marsh cord grass in the Chesapeake Bay watershed. Consistent with its isolation from decaying plant matter, S. degradans strain 2-40 is able to degrade many complex polysaccharides, including cellulose, pectin, xylan, and chitin, which are common components of the cell walls of higher plants. S. degradans strain 2-40 is also able to depolymerize algal cell wall components, such as agar, agarose, and laminarin, as well as protein, starch, pullulan, and alginic acid. In addition to degrading this plethora of polymers, S. degradans strain 2-40 can utilize each of the polysaccharides as the sole carbon source. Therefore, S. degradans strain 2-40 is not only an excellent model of microbial degradation of insoluble complex polysaccharides (ICPs) but can also be used as a paradigm for complete metabolism of these ICPs. ICPs are polymerized saccharides that are used for form and structure in animals and plants. They are insoluble in water and therefore are difficult to break down.
[0007] Microbulbifer degradans strain 2-40 requires at least 1% sea salts for growth and will tolerate salt concentrations as high as 10%. It is a highly pleomorphic, Gram-negative bacterium that is aerobic, generally rod-shaped, and motile by means of a single polar flagellum. Previous work has determined that 2-40 can degrade at least 10 different carbohydrate polymers (CP), including agar, chitin, alginic acid, carboxymethylcellulose (CMC), 6-glucan, laminarin, pectin, pullulan, starch and xylan (Ensor, Stotz et al. 1999). In addition, it has been shown to synthesize a true tyrosinase (Kelley, Coyne et al. 1990). 16S rDNA analysis shows that 2-40 is a member of the gamma-subclass of the phylum Proteobacteria, related to Microbulbifer hydrolvyicus (Gonzalez and Weiner 2000) and to Teridinibacter sp., (Distel. Morrill et al. 2002) cellulolytic nitrogen-fixing bacteria that are symbionts of shipworms.
[0008] The agarase, chitinase and alginase systems have been generally characterized. Zymogram activity gels indicate that all three systems are comprised of multiple depolymerases and multiple lines of evidence suggest that at least some of these depolymerases are attached to the cell surface (Stotz 1994: Whitehead 1997; Chakravorty 1998). Activity assays reveal that the majority of 2-40 enzyme activity resides with the cell fraction during logarithmic growth on CP, while in later growth phases the bulk of the activity is found in the supernatant and cell-bound activity decreases dramatically (Stotz 1994). Growth on CP is also accompanied by dramatic alterations in cell morphology. Glucose-grown cultures of 2-40 are relatively uniform in cell size and shape, with generally smooth and featureless cell surfaces. However, when grown on agarose, alginate, or chitin, 2-40 cells exhibit novel surface structures and features.
[0009] These exo- and extra-cellular structures (ES) include small protuberances, ger bleb-like structures that appear to be released from the cell, fine fimbrae or pili, and a network of fibril-like appendages which may be tubules of some kind. Immunoelectron microscopy has shown that agarases, alginases and/or chitinases are localized in at least some types of 2-40 ES. The surface topology and pattern of immunolocalization of 2-40 enzymes to surface protuberances are very similar to what is seen with cellulolytic members of the genus Clostridium.
[0010] There exists a need to identify enzyme systems that use cellulose as a substrate, express the genes encoding the proteins using suitable vectors, identify and isolate the amino acid products (enzymes and non-enzymatic products), and use these products as well as organisms containing these genes for purposes such as those described in the Bhat paper.
SUMMARY OF THE INVENTION
[0011] One aspect of the present invention is directed to systems of plant wallactive carbohydrases and related proteins.
[0012] A further aspect of the invention is directed to a method for the degradation of substances comprising cellulose. The method involves contacting the cellulose containing substances with one or more compounds obtained from Saccharophagus degradans strain 2-40.
[0013] Another aspect of the present invention is directed to groups of enzymes that catalyze reactions involving cellulose.
[0014] Another aspect of the present invention is directed to polynucleotides that encode polypeptides with cellulose degrading or cellulose binding activity.
[0015] A further aspect of the invention is directed to chimeric genes and vectors comprising genes that encode polypeptides with cellulose depolymerase activity.
[0016] A further aspect of the invention is directed to a method for the identification of a nucleotide sequence encoding a polypeptide comprising any one of the following activities from S. degradans : cellulose depolymerase, or cellulose binding. An S. degradans genomic library can be constructed in E. coli and screened for the desired activity. Transformed E. coli cells with specific activity are created and isolated.
[0017] Further aspects of the invention are directed to utilization of the cellulose degrading substances in food, beer, wine, animal feeds, textile production and laundering, pulp and paper industry, and agricultural industries.
[0018] Other aspects, features, and advantages of the invention will become apparent from the following detailed description, which when taken in conjunction with the accompanying figures, which are part of this disclosure, and which illustrate by way of example the principles of this invention.
BRIEF DESCRIPTION OF THE FIGURES
[0019] FIG. 1A shows the chemical formula of cellulose;
[0020] FIG. 1B illustrates the physical structure of cellulose;
[0021] FIG. 2A illustrates the degradation of cellulose fibrils;
[0022] FIG. 2B shows the chemical representation of cellulose degradation tocellobiose and glucose;
[0023] FIG. 3 shows SDS-PAGE and Zymogram analysis of 2-40 culturesupernatants;
[0024] FIG. 4 lists the predicted cellulases of S. degradans 2-40 the sequences from FIGS. 4-10 are disclosed as SEQ ID) NOs 1-214, respectively in order of appearance, 1—Acronyms, cel=cellulase, ced=cellodextrinase, bql=6-glucosidase, cep=cellobiose/cellodextrin phosphorylase; 2—Protein identified by tandem mass spectrometry in supernatant concentrates. Growth substrates: av=avicel, aq=agarose, al=alginate cm=CMC, xn=xylan: 3—MW and amino acid count calculated using the protParam (protein parameters) tool at the Expasy website based on the DOE/JGI gene model amino acid sequence translations and includes any predicted signal peptide; 4—Predictions of function and GH, GT and CBM module determination according to CAZy ModO analysis by B. Henrissat, AFMB-CRNS; Da 88 ers (t) indicate lack of a secretion signal sequence; 5-Nonstandard module abbreviations, LPB=lipobox motif, PSL=polyserine linker. EPR=glutamic acid-proline rich region, PLP=phospholipase-like domain, number in parentheses indicates the length of the indicated feature in amino acid residues; 6—Refseq accession number of gene amino acid sequence from the Entrez protein database;
[0025] FIG. 5 lists the predicted xylanases, xylosidases and related accessories of M. degradans 2-40;
[0026] FIG. 6 lists the predicted pectinases and related accessories of S. degradans 2-40, 1—Acronyms, pel=pectate lyase, pes=pectin methylesterase, rql=rhamnogalacturonan lyase; 2—MW and amino acid count calculated using the protParam (protein parameters) tool at the Expasy website based on the DOE/JGI gene model amino acid sequence translations and includes any predicted signal peptide; 3-Predictions of function and GH, GT, PL, CE and CBM module determination according to CAZy ModO analysis by B. Henrissat, AFMB-CRNS; 4—Module abbreviations, CE=carbohydrate esterase, FN3=fibronectin type3-like domain, LPB=lipobox motif. PL=pectate lyase, PSR=polyserine region, EPR=glutamic acid-proline rich region, number in parentheses indicates the length of the indicated feature in amino acid residues; 5—Refseq accession number of gene model amino acid sequence from the Entrez Pubmed database:
[0027] FIG. 7 lists the arabinanases and arabinogalactanases of S. degradans 2-40;
[0028] FIG. 8 lists the mannanases of S. degradans 2-40;
[0029] FIG. 9 lists the laminarinases of S. Degradans 2-40, Superscripts: 1-Acronyms, lam=laminarinase; 2—MW and amino acid count calculated using the protParam (protein parameters) tool at the Expasy website based on the DOE/JGI gene model amino acid sequence translations and includes any predicted signal peptide; 3-Predictions of function and GH, GT, PL, CE and CBM module determination according to CAZy Mod( ) analysis by B. Henrissat, AFMB-CRNS; 4—Module abbreviations: TSP3=thrombospondin type3 repeats, COG3488=thiol-oxidoreductase like domain of unknown function (Interestingly, a similar domain is found in cbm32A: see table 7), PSD=polyserine domain. TMR=predicted transmembrane region, FN3=tibronectin type3 like domain, EPR=qlutamic acid-proline rich region, CADG=cadherin-like calcium binding motif, number in parentheses indicates the length of the indicated feature in amino acid residues; 5—Refseq accession number can be used to retrieve the gene model amino acid sequence from the Entrez Pubmed database:
[0030] FIG. 10 lists selected carbohydrate-binding module proteins of S. degradans 2-40; and
[0031] FIG. 11 lists the recombinant proteins of S. degradans 2-40 and a comparison of predicted vs. observed molecular weights thereof.
DETAILED DESCRIPTION
[0032] Analysis of the genome sequence of S. degradans 2-40 reveals an abundance of genes coding for enzymes that are predicted to degrade plant-derived carbohydrates. To date, 2-40 is the only sequenced marine bacterium with apparently complete cellulase and xylanase systems, as well as a number of other systems containing plant-wall active carbohydrases.
[0033] Thus it appears that 2-40 can play a significant role in the marine carbon cycle, functioning as a “super-degrader” that mediates the breakdown of CP from various algal, plantal, and invertebrate sources. The remarkable enzymatic diversity, novel surface features (ES), and the apparent localization of carbohydrases to ES make S. degradans 2-40 an intriguing organism in which to study the cell biology of CP metabolism and surface enzyme attachment.
[0034] It has now been discovered that 2-40 has a complete complement of enzymes, suitably positioned, to degrade plant cell walls. This has been accomplished by the following approaches: a) annotation and genomic analysis of 2-40 plant-wall active enzyme systems, b) identification of enzymes and other proteins which contain domains or motifs that may be involved in surface enzyme display, c) the development of testable models based on identified protein motifs, and d) cloning and expression of selected proteins for the production of antibody probes to allow testing of proposed models of surface enzyme display using immunoelectron microscopy.
[0035] These efforts have been greatly facilitated by the recent sequencing of the genome of 2-40, allowing a strategy where genes which code for proteins with potential involvement in surface attachment may be identified based on sequence homology with modules or domains known to function in surface attachment and/or adhesion.
[0036] Enzymatic and non-enzymatic ORFs with compelling sequence elements are identified using BLAST and other amino acid sequence alignment and analysis tools. Genes of interest can be cloned into E. coli , expressed with in-frame polyhistidine affinity tag fusions and purified by nickel ion chromatography, thus providing the means of identifying and producing recombinant 2-40 proteins for study and antibody probe production.
[0037] The genome sequence of 2-40 was recently obtained in conjunction with the Department of Energy's Joint Genome Initiative (JGI). The finished draft sequence dated Jan. 19, 2005 comprises 5.1 Mbp contained in a single contiguous sequence. Automated annotation of open reading frames (ORFs) was performed by the computational genomics division of the Oak Ridge National Laboratory (ORNL), and the annotated sequence is available on the World Wide Web.
[0038] The initial genome annotation has revealed a variety of carbohydrases, including a number of agarases, alginases and chitinases. Remarkably, the genome also contains an abundance of enzymes with predicted roles in the degradation of plant cell wall polymers, including a number of ORFs with homology to cellulases, xylanases, pectinases, and other glucanases and glucosidases. In all, over 180 open reading frames with a probable role in carbohydrate catabolism were identified in the draft genome.
[0039] To begin to define the cellulase, xylanase and pectinase systems of 2-40, genes were initially classified as belonging to one of those systems by BLAST homology. Ambiguous ORFs were tentatively assigned to the class of the best known hit. Other tools used to refine this tentative classification include Pfam (Protein families database of alignments and HMMs and SMART (Simple Modular Architecture Research Tool) which use multiple alignments and hidden Markov models (statistical models of sequence consensus homology) to identify discreet modular domains within a protein sequence. These analyses were relatively successful; however, a number of ORFs remained difficult to classify based on sequence homology alone.
[0040] Enzymes have traditionally been classified by substrate specificity and reaction products. In the pre-genomic era, function was regarded as the most amenable (and perhaps most useful) basis for comparing enzymes and assays for various enzymatic activities have been well-developed for many years, resulting in the familiar EC classification scheme. Cellulases and other O-Glycosyl hydrolases, which act upon glycosidic bonds between two carbohydrate moieties (or a carbohydrate and non-carbohydrate moiety—as occurs in nitrophenol-glycoside derivatives) are designated as EC 3.2.1.—, with the final number indicating the exact type of bond cleaved. According to this scheme an endo-acting cellulase (1,4-8-endoglucanase) is designated EC 3.2.1.4.
[0041] With the advent of widespread genome sequencing projects and the ease of determining the nucleotide sequence of cloned genes, ever-increasing amounts of sequence data have facilitated analyses and comparison of related genes and proteins on an unprecedented scale. This is particularly true for carbohydrases; it has become clear that classification of such enzymes according to reaction specificity, as is seen in the E.C. nomenclature scheme, is limited by the inability to convey sequence similarity. Additionally, a growing number of carbohydrases have been crystallized and their 3-D structures solved.
[0042] One of the major revelations of carbohydrase sequence and structure analyses is that there are discreet families of enzymes with related sequence, which contain conserved three-dimensional folds that can be predicted based on their amino acid sequence. Further, it has been shown that enzymes with the same three-dimensional fold exhibit the same stereospecificity of hydrolysis, even when they catalyze different reactions (Henrissat, Teeri et al. 1998: Coutinho and Henrissat 1999).
[0043] These findings form the basis of a sequence-based classification of carbohydrase modules which is available in the form of an internet database, the Carbohydrate-Active enZYme server (CAZy)(Coutinho and Henrissat 1999; Coutinho and Henrissat 1999).
[0044] CAZy defines four major classes of carbohydrases, based on the type of reaction catalyzed: Glycosyl Hydrolases (GH's), Glycosyltansferases (GT's), Polysaccharide Lyases (PL's), and Carbohydrate Esterases (CE's). GH's cleave glycosidic bonds through hydrolysis. This class includes many familiar polysaccharidases such as cellulases, xylanases, and agarases. GT's generally function in polysaccharide synthesis, catalyzing the formation of new glycosidic bonds through the transfer of a sugar molecule from an activated carrier molecule, such as uridine diphosphate (UDP), to an acceptor molecule. While GT's often function in biosynthesis, there are examples where the mechanism is exploited for bond cleavage, as occurs in the phosphorolytic cleavage of cellobiose and cellodextrins (Lou, Dawson et al. 1996). PL's use a 6-elimination mechanism to mediate bond cleavage and are commonly involved in alginate and pectin depolymerization. CE's generally act as deacetylases on O- or N—substituted polysaccharides. Common examples include xylan and chitin deacetylases. Sequence-based families are designated by number within each class, as is seen with GH5: glycosyl hydrolase family 5. Members of GHS hydrolyze 6-1,4 bonds in a retaining fashion, using a double-displacement mechanism which results in retention of the original bond stereospecificity. Retention or inversion of anomeric configuration is a general characteristic of a given GH family (Henrissat and Bairoch 1993; Coutinho and Henrissat 1999). Many examples of endocellulases, xylanases and mannanases belonging to GHS have been reported, illustrating the variety of substrate specificity possible within a GH family. Also, GH5s are predominantly endohydrolases—cleaving chains of their respective substrates at random locations internal to the polymer chains. While true for GH5, this generalization does not hold for many other GH families. In addition to carbohydrases, the CAZy server defines numerous families of Carbohydrate Binding Modules (CBM). As with catalytic modules. CBM families are designated based on amino acid sequence similarity and conserved three-dimensional folds.
[0045] The CAZyme structural families have been incorporated into a new classification and nomenclature scheme, developed by Bernard Henrissat and colleagues (Henrissat. Teeri et al. 1998). Traditional gene/protein nomenclature assigns an acronym indicating general function and order of discovery; in this scheme an organism's cellulose genes are designated celA, celB, etc., regardless of their actual mechanism of action on cellulose. Some researchers have attempted to convey more information by naming cellulases as endoglucanases (engA, engB) or cellobiohydrolases (cbhA, cbhB), however this requires determination of function in vitro and still fails to convey relatedness of protein sequence and structure. CAZyme nomenclature retains the familiar acronym to indicate the functional system a gene belongs to and incorporates the family number designation. Capital letters after the family number indicate the order of report within a given organism system. An example is provided by two endoglucanases, CenA and CenB, of Cellulomonas fimi . In the old nomenclature nothing can be deduced from the names except order of discovery.
[0046] Naming them Cel6A and Cel9A, respectively, makes it immediately clear that these two cellulases are unrelated in sequence, and so belong to different GH families (where Cel stands for cellulase, and 9 for glycosyl hydrolase family nine). While this scheme does not distinguish between endo and exo—activity, these designations are not absolute and can be included in discussion of an enzyme when relevant (i.e. the cellobiohydrolase Cel6A, the endoxylanase Xyn 10B). Catalytic modules take precedence in naming carbohydrases; since many (or even most) carbohydrases contain at least one CBM, they are named for their enzymatic module. If more than one catalytic domain is present, they are named in order from N-terminus to C-terminus, i.e. cel9A-cel48A contains a GH9 at the amino-terminus and a GH48 at the carboxyterminus. Both domains act against cellulose. There are, however, many examples of CBM modules occurring on proteins with no predicted carbohydrase module. In the absence of some other predicted functional domain (like a protease) these proteins are named for the CBM module family. If there are multiple CBM families present, then naming is again from amino to carboxy end, i.e. cbm2D-cbm 10 A (Henrissat, Teeri et al. 1998). This nomenclature has been widely accepted and will be used in the naming of all 2-40 plant-wall active carbohydrases and related proteins considered as part of this study.
[0047] The cell walls of higher plants are comprised of a variety of carbohydrate polymer (CP) components. These CP interact through covalent and non-covalent means, providing the structural integrity plants required to form rigid cell walls and resist turgor pressure. The major CP found in plants is cellulose, which forms the structural backbone of the cell wall. See FIG. 1A . During cellulose biosynthesis, chains of poly-13-1,4-D-glucose self associate through hydrogen bonding and hydrophobic interactions to form cellulose microfibrils which further self-associate to form larger fibrils. Cellulose microfibrils are somewhat irregular and contain regions of varying crystallinity. The degree of crystallinity of cellulose fibrils depends on how tightly ordered the hydrogen bonding is between its component cellulose chains. Areas with less-ordered bonding, and therefore more accessible glucose chains, are referred to as amorphous regions ( FIG. 1B ). The relative crystallinity and fibril diameter are characteristic of the biological source of the cellulose (Beguin and Aubert 1994; Tomme, Warren et al. 1995; Lynd, Weimer et al. 2002). The irregularity of cellulose fibrils results in a great variety of altered bond angles and steric effects which hinder enzymatic access and subsequent degradation.
[0048] The general model for cellulose depolymerization to glucose involves a minimum of three distinct enzymatic activities (See FIGS. 2A and 2B ). Endoglucanases cleave cellulose chains internally to generate shorter chains and increase the number of accessible ends, which are acted upon by exoglucanases. These exoglucanases are specific for either reducing ends or non-reducing ends and frequently liberate cellobiose, the dimer of cellulose (cellobiohydrolases). The accumulating cellobiose is cleaved to glucose by cellobiases ((3-1,4-glucosidases). In many systems an additional type of enzyme is present: cellodextrinases are 6-1,4-glucosidases which cleave glucose monomers from cellulose oligomers, but not from cellobiose. Because of the variable crystallinity and structural complexity of cellulose, and the enzymatic activities required for is degradation, organisms with “complete” cellulase systems synthesize a variety of endo and/or exo-acting 6-1,4-glucanases.
[0049] For example, Cellulomonas fimi and Thermomonospora fusca have each been shown to synthesize six cellulases while Clostridium thermocellum has as many as 15 or more (Tomme, Warren et al. 1995). Presumably, the variations in the shape of the substrate-binding pockets and/or active sites of these numerous cellulases facilitate complete cellulose degradation (Warren 1996). Organisms with complete cellulase systems are believed to be capable of efficiently using plant biomass as a carbon and energy source while mediating cellulose degradation. The ecological and evolutionary role of incomplete cellulose systems is less clear, although it is believed that many of these function as members of consortia (such as ruminal communities) which may collectively achieve total or near-total cellulose hydrolysis (Ljungdahl and Eriksson 1985; Tomme, Warren et al. 1995).
[0050] In the plant cell wall, microfibrils of cellulose are embedded in a matrix of hemicelluloses (including xylans, arabinans and mannans), pectins (galacturonans and galactans), and various 6-1,3 and 6-1,4 glucans. These matrix polymers are often substituted with arabinose, galactose and/or xylose residues, yielding arabinoxylans, galactomannans and xyloglucans—to name a few (Tomme, Warren et al. 1995; Warren 1996; Kosugi, Murashima et al. 2002: Lynd, Weimer et al. 2002). The complexity and sheer number of different glycosyl bonds presented by these non-cellulosic CP requires specific enzyme systems which often rival cellulase systems in enzyme count and complexity. Because of its heterogeneity, plant cell wall degradation often requires consortia of microorganisms (Ljungdahl and Eriksson 1985; Tomme, Warren et al. 1995).
[0051] Objectives— M degradans synthesizes complete multi-enzyme systems that degrade the major structural polymers of plant cell walls. A) define cellulase and xylanase systems, determining the activities of genes for which function cannot be predicted by sequence homology; and B) genomic identification and annotation of other plant-degrading enzyme systems by sequence homology (i.e. pectinases, laminarinases, etc.).
[0052] Experimental Results
[0053] I: Genomic, Proteomic and Functional Analyses of 2-40 Plant-Wall Activeenzymes
[0054] From the ORNL annotation it is clear that the 2-40 genome contains numerous enzymes with predicted activity against plant cell wall polymers. This is particularly surprising since 2-40 is an estuarine bacterium with several complex enzyme systems that degrade common marine polysaccharides such as agar; alginate, and chitin. Defining multienzyme systems based on automated annotations is complicated by the presence of poorly conserved domains and/or novel combinations of domains. There are many examples of this in the plant-wall active enzymes of 2-40. Accordingly, the ORNL annotations of carbohydrase ORFs were manually reviewed with emphasis on the modular composition and then assigned to general groups based on the substrate they were likely to be involved with (i.e. cellulose or xylan degradation). These genomic sequence analyses resulted in a pool of about 25 potential cellulases, 11 xylanases and 17 pectinases.
[0055] When sequence homology is well-conserved, highly accurate predictions of function are possible. Therefore, to verify the presence of functioning cellulase and xylanase systems in M degradans , zymograms and enzyme activity assays were performed as discussed below. Also, attempts were made to identify enzymes from 2-40 culture supernatants using Mass Spectrometry based proteomics.
[0056] Next, more sophisticated genomic analyses were used to predict function where possible and to identify ORFs which require functional characterization to determine their roles, if any, in the cellulase and xylanase systems. ORFs which belong to other plant wall-active enzyme systems were tentatively classified based on the sequence analyses and functional predictions of B. Henrissat.
[0057] To gain insight into the induction and expression of 2-40 cellulases and xylanases, specific activities were determined for avicel and xylan-grown cells and supernatants by dinitrosalicylic acid reducing-sugar assays (DNSA assays), as discussed in the Experimental Protocols section at the end of this proposal. Xylanase activity was measured for avicel-grown cultures, and vice versa, in order to investigate possible co-induction of activity by these two substrates which occur together in the plant cell wall.
[0058] Growth on either avicel or xylan yields enzymatic activity against both substrates, suggesting co-induction of the cellulase and xylanase systems. As with other 2-40 carbohydrase systems, highest levels of activity were induced by the homologous substrate. The results also reveal some key differences in the expression of these two systems. When grown on avicel, cellulase activity is cell-associated in early growth and accumulates significantly in late-stage supernatants. Cell and supernatant fractions exhibit low levels of xylanase activity that remain roughly equal throughout all growth phases. In contrast, xylan-grown cultures exhibit the majority of xylanase and cellulase activity in the cellular fraction throughout the growth cycle. Cellulase activity does not accumulate in the supernatant and xylanase activity accumulates modestly, but still remains below the cell-bound activity.
[0059] Enzyme activity gels (zymograms) of avicel and xylan grown cell pellets and culture supernatants were analyzed to visualize and identify expressed cellulases and xylanases. The zymograms revealed five xylanolytic bands in xylan-grown supernatants ( FIG. 3 ), four of which correspond well with the calculated MW of predicted xylanases (xyl/arb43G-xyn1 OD: 129.6 kDa, xyn10 E: 75.2 kDa, xyn 1 OC: 42.3 kDa, and xyn11A: 30.4 kDa: see Table 2). Avicel-grown cultures showed eight active bands with MWs ranging from 30-150 kDa in CMC zymograms. CMC is generally able substrate for endocellulase activity. These zymograms clearly demonstrate that 2-40 synthesizes a number of endocellulases of varied size during growth on avicel—indicative of a functioning multienzyme cellulase system. Together, the CMC and xylan zymograms confirm the results of the genomic analyses and the inducible expression of multienzyme cellulase and xylanase systems in M degradans 2-40.
[0060] To identify individual cellulases and xylanases produced during growth on CP, culture supernatants were subjected to proteomic analysis using reversed-phase high-performance liquid chromatography (RP-HPLC) coupled with tandem Mass Spectrometry (MS/MS). The power resulting from separating the peptides on the RPHPLC column prior to electrospray ionization and MS/MS analysis allows the identification of a great number of proteins from complex samples (Smith, Loo et al. 1990; Shevchenko, Wilm et al. 1996; Jonsson. Aissouni et al. 2001). These analyses confidently identified over 100 different non-enzymatic proteins and a number of carbohydrases, including a xylanase, two xylosidases, a cellulase, and two cellodextrinases. An agarase was identified during additional analyses of agarose-grown supernatant.
[0061] Gel-slice digestion, extraction, and MS/MS analyses performed at the Stanford University Mass Spectrometry facility identified two annotated cellulases from an avicel-grown supernatant sample. One, designated cel5H, has a predicted MW of 67 kDa and was identified from a band with an apparent MW of 75 kDa. The other, cel9B, has a predicted MW of 89 kDa, but an apparent MW of 120 kDa. The discrepancy between the predicted and apparent MW of cel9B is consistent with similar instances where certain 2-40 proteins, cloned and expressed in E coli , exhibit apparent MWs which are 30-40% higher than their predicted MW.
[0062] The amino acid translations of all gene models in the 2-40 draft genome were analyzed on the CAZy ModO (Carbohydrase Active enZyme Modular Organization) server at AFMB-CRNS. This analysis identified all gene models that contain a catalytic module (GH, GT, PL, or CE) and/or a CBM. In all, the genome contains 222 gene models containing CAZy domains, most of which have modular architecture. Of these, 117 contain a GH module, 39 have GTs, 29 PLs, and 17 CE. Many of these carry one or more CBM from various families, that contain a CBM but no predicted carbohydrase domain.
[0063] Detailed comparisons of 2-40 module sequences to those in the ModO database allowed specific predictions of function for modules where the sequence of the active site is highly conserved. For example, Cel9B (from the gel slice MS/MS) contains a GH9 module which is predicted to function as an endocellulase, a CBM2 and a CBM 10 module.
[0064] When catalytic module sequences are less conserved, only a general mechanism can be predicted. This is the case with gly5M which contains a GH5 predicted to be either a 1,3 or 1,4 glucanase—sequence analysis cannot be certain which, and so the acronym designation “gly” for glycanase.
[0065] The results of this detailed evaluation and analysis were used to assign genes to cellulase, xylanase, pectinase, laminarinase, arabinanase and mannanase systems. Each system was also assigned the relevant accessory enzymes, i.e. cellobiases belong to the cellulase system and xylosidases belong to the xylanase system. Genes with less-conserved GH modules which have the most potential to function as cellulases, xylanases or accessories were identified and designated as needing demonstration of function.
[0066] The results of the ORNL annotation, follow-up annotation analyses, proteomic (mass spectrometry) analyses, CAZyme modular analyses and functional predictions have been incorporated into FIGS. 4-11 , which contain tables that summarize the predicted plant wall active carbohydrases and selected CBM only genes of 2-40.
[0067] The genes chosen for cloning and functional analysis include the carbohydrases gly3C, gly5K, gly5M, gly9C, and gly43M. Because the active site of gly5L is highly homologous to that of gly5K, its activity is inferred from the results obtained from gly5K. Four of the 20 “CBM only” proteins, cbm2A, cbm2B, cbm2C and cbm2D-cbm10A are included in activity assays to investigate their predicted lack of enzymatic function. These four contain CBM2 modules that are predicted to bind to crystalline cellulose. This predicted affinity is the reason for their inclusion in activity assays; those proteins that bind to cellulose are most likely to contain cellulase or xylanase modules which were not detected by sequence analysis. With CBM only proteins, a lack of detected enzyme activity will confirm the absence of a catalytic domain (CD).
[0068] In order to define the complete cellulase and xylanase systems of M degradans , those enzymes which may belong to the systems but cannot be confidently assigned based on sequence homology will be expressed, purified and assayed for activity as described in the Experimental Protocols. To date, gly3C, gly5K, gly5M, gly9C and gly43M, as well as cbm2A, cbm2B, cbm2C and cbm2D-cbm10A, have been cloned into expression strains as pETBlue2 (Novagen) constructs. This vector places expression under the control an inducible T7 lac promoter and incorporates a C-terminal 6×Histidine tag, allowing purification of the recombinant protein by nickel ion affinity. Successful cloning and expression of these proteins was confirmed by western blots using a-HisTag® monoclonal antibody (Novagen). All expressed proteins have apparent MWs which are close to, or larger, than their predicted MW (Table 8) except for Cbm2DCbm10A which appears to be unstable; two separate attempts to clone and express this protein have resulted in HisTag® containing bands which occur near the dye front in western blots, suggesting proteolytic degradation of this gene product. An additional enzyme, Cel5A, has been cloned and expressed for use as an endocellulase positive control in activity assays. Cel5A has a predicted MW of 129 kDa, contains two GH5 modules, and is highly active in HE-cellulose zymograms.
[0069] The major criteria for assigning function will be the substrate acted upon, and the type of activity detected. As such, the various enzyme activity assays will focus on providing a qualitative demonstration of function rather than on rigorously quantifying relative activity levels. The assays required are dictated by the substrate being tested, and are discussed in more detail in Experimental Protocols. For cellulose it is important to distinguish between 13-1,4-endoglucanase (endocellulase), 13-1,4-exoglucanase (cellobiohydrolase), and 13-1,4-glucosidase (cellobiase) activities. This will be accomplished using zymograms to assay for endocellulase, DNSA reducing-sugar assays for cellobiohydrolase, and p-nitrophenol-13-1,4-cellobioside (pnp-cellobiose) for cellobiase activity. The combined results from all three assays will allow definition of function as follows: a positive zymogram indicates endocellulase activity, a negative zymogram combined with a positive DNSA assay and a negative pnp-cellobiose assay indicates an exocellulase, while a negative zymogram and DNSA with a positive pnp-cellobiose result will imply that the enzyme is a cellobiase.
[0070] Xylanase (13-1,4-xylanase), laminarinase (13-1,3-glucanase), and mixed glucanase (13-1,3(4)-glucanase) activity will be determined by xylan, laminarin and barley glucan zymograms, respectively. Unlike cellulose, there do not appear to be any reports of “xylobiohydrolases” or other exo-acting enzymes which specifically cleave dimers from these substrates. Thus zymograms will suffice for demonstrating depolymerase (endo) activity and pnp-derivatives will detect monosaccharide (exo) cleavage. The pnp-derivatives used in this study will include pnp-a-L-arabinofuranoside,-a-L-arabinopyranoside,-13-L-arabinopyranoside,-P-D-cellobioside, -a-D-xylopyranoside and -p-D-xylopyranoside. These substrates were chosen based on the possible activities of the domains in question. The assays will allow determination of function for any a- and p-arabinosidases, P-cellobiases, P-xyiosidases, bifunctional aarabinosidase/p-xylosidascs, and a-xylosidases—which cleave a-linked xylose substituents from xyloglucans. The pnp-derivative assays will be run in 96-well microtiter plates using a standard curve of p-nitrophenol concentrations, as discussed in Experimental Protocols.
[0071] The combination of assays for 13-1,4-, P-1,3-, and 13-1,3(4)-glucanase activities, as well as for 13-1,4-xylanase and the various exo-glycosidase activities should clearly resolve the function of the ambiguous carbohydrases. Proteins with demonstrated activity will be assigned to the appropriate enzyme system.
[0072] Experimental Protocols
[0073] Zymograms
[0074] All activity gels were prepared as standard SDS-PAGE gels with the appropriate CP substrate incorporated directly into the separating gel. Zymograms are cast with 8% polyacrylamide concentration and the substrate dissolved in dH 2 O and/or gel buffer solution to give a final concentration of 0.1% (HE-cellulose), 0.15% (barley 13-glucan), or 0.2% (xylan). Gels are run under discontinuous conditions according to the procedure of Laemmli (Laemmli 1970) with the exception of an 8 minute treatment at 95° C. in sample buffer containing a final concentration of 2% SDS and 100 mM dithiothreitol (DTT). After electrophoresis, gels are incubated at room temperature for 1 hour in 80 ml of a renaturing buffer of 20 mM PIPES buffer pH 6.8 which contains 2.5% Triton X-100, 2 mM DTT and 2.5 mM CaCl 2 . The calcium was included to assist the refolding of potential calcium-binding domains such as the tsp3s of Lam 16A.
[0075] After the 1 hour equilibration, gels were placed in a fresh 80 ml portion of renaturing buffer and held overnight at 4° C. with gentle rocking. The next morning gels were equilibrated in 80 ml of 20 mM PIPES pH6.8 for 1 hour at room temperature, transferred to a clean container, covered with the minimal amount of PIPES buffer and incubated at 37° C. for 4 hours. Following incubation gels were stained for 30 minutes with a solution of either 0.25% Congo red in dH 2 O (HE-cellulose, p-glucan and xylan) or 0.01% Toluidine blue in 7% acetic acid. Gels were destained with 1M NaCl for Congo red and dH 2 O for Toluidine blue until clear bands were visible against a stained background.
[0076] Nelson-Somogyi Reducing-Sugar Assays
[0077] Purified proteins were assayed for activity using a modification of the Nelson-Somogyi reducing sugar method adapted for 96-well microtiter plates, using 50 ul reaction volumes (Green, Clausen et al. 1989). Test substrates included avicel, CMC, phosphoric-acid swollen cellulose (PASC), Barley glucan, laminarin, and xylan dissolved at 1% in 20 mM PIPES pH 6.8 (Barley glucan and laminarin. 0.5%). Barley glucan, laminarin and xylan assays were incubated 2 hours at 37° C.; avicel, CMC and PASC assays were incubated 36 hours at 37° C. Samples were assayed in triplicate, corrected for blank values, and levels estimated from a standard curve. Protein concentration of enzyme assay samples was measured in triplicate using the Pierce BCA protein assay according to the manufacture's instructions. Enzymatic activity was calculated, with one unit (U) defined as 11.1M of reducing sugar released/minute and reported as specific activity in U/mg protein.
[0078] Exoglycosidase Activity Assays: Pnp-Derivatives
[0079] Purified proteins were assayed for activity against pNp derivatives of α-L-arabinofuranoside,-α-L-arabinopyranoside, -β-L-arabinopyranoside,-β-D-cellobioside,-α-D-glucopyranoside,-β-D-glucopyranoside,-α-D-xylopyranoside and -β-Dxylopyranoside, 25 μl of enzyme solution was added to 1251 μl of 5 mM substrate solution in 20 mM PIPES pH 6.8, incubated for 30 min at 37° C. and A 405 was determined. After correcting for blank reactions, readings were compared to a p-nitrophenol standard curve and reported as specific activities in U/mg protein, with one unit (U) defined as 1 μlmol p-Np/min.
[0080] Mass Spectrometry and Proteomic Analyses
[0081] Stationary-phase supernatants from avicel, CMC, and xylan-grown cultures were concentrated to 25× by centrifugal ultrafiltration using microcon or centricon devices (Millipore). Sample protein concentrations were determined by the BCA protein assay. Samples were exchanged into 100 mM Tris buffer, pH 8.5, which also contained 8M urea and 10 mM DTT. Samples were incubated 2 hours at 37° C. with shaking to denature the proteins and reduce disulfide bonds. After reduction, 1M iodoacetate was added to a final concentration of 50 mM and the reaction was incubated 30 minutes at 25° C. in the dark. This step alkylates the reduced cysteine residues, thereby preventing reformation of disulfide bonds. The samples are then exchanged into 50 mM Tris, 1 mM Ca01 2 , pH 8.5 using microcon devices. The denatured, reduced, and alkylated sample is digested into peptide fragments using proteomics-grade trypsin (Promega) at a 1:50 enzyme (trypsin) to substrate (supernatant) ratio. Typical digestion reactions were around 1501 total volume. Digestions were incubated overnight at 37° C., stopped by addition of 99% formic acid to a final concentration of 1% and analyzed by RPHPLC-MS/MS at the UMCP College of Life Sciences CORE Mass Spectrometry facility.
[0082] Peptide fragments were loaded onto a Waters 2960 HPLC fitted with a 12 cm microbore column containing 018 as the adsorbent and eluted with a linear gradient of increasing acetonitrile (CH 3 CN) concentration into an electrospray ionization apparatus. The electrospray apparatus ionized and injected the peptides into a Finnagin LCQ tandem Mass Spectrometer. Automated operating software controlled the solvent gradient and continually scanned the eluted peptides. The program identifies each of the three most abundant ion species in a survey scan, isolates each of them in the Mass Spectrometer's ion trap and fragments them by inducing collisions with helium molecules. The resulting sub-fragment masses are recorded for further analysis by peptide analysis packages like SEQUEST and MASCOT. After the three subscan and collision cycles have completed, the MS takes another survey scan and the cycle repeats until the end of the run, usually about three hours. The raw MS reads are used by the analysis software to generate peptide fragment sequences, which were compared to amino acid sequence translations of all gene models in the 2-40 draft genome. Peptide identity matches were evaluated using accepted thresholds of statistical significance which are specific for each program.
[0083] Cloning and Expression of 2-40 Proteins in E coli
[0084] The basic cloning and expression system uses pETBlue2 (Novagen) as the vector, E coli DH5a (invitrogen) as the cloning strain, and E coli BL-21(DE3) Tuner cells (Novagen) for protein expression strain. This system allows the cloning of toxic or otherwise difficult genes because the vector places expression under the control of a T7 lac promoter-which is lacking in the cloning strain DH5a, thereby abolishing even low-level expression during plasmid screening and propagation. After the blue/white screen, plasmids are purified from DH5a and transformed into the expression host (Tuners). The Tuner strain has the T7 lac promoter, allowing IPTG-inducible expression of the vector-coded protein and lacks the Lon and Omp proteases.
[0085] The nucleotide sequences of gene models were obtained from the DOEJGI's Microbulbifer degradans genome web server and entered into the PrimerQuest™ design tool provided on Integrated DNA Technologies web page. The design parameters were Optimum T m 60° C., Optimum Primer Size 2 Ont. Optimum GC %=50, and the product size ranges were chosen so that the primers were selected within the first and last 100 nucleotides of each ORF in order to clone as much of the gene as reasonably possible. The cloning and expression vector, pETBlue2, provides a C-terminal 6×Histidine fusion as well as the start and stop codon for protein expression. Thus, careful attention to the frame of the vector and insert sequences is required when adding 5′ restriction sites to the PCR primers. The resulting “tailed primers” were between 26 to 3 Ont long, and their sequences were verified by “virtual cloning” analysis using the PDRAW software package. This program allows vector and insert DNA sequences to be cut with standard restriction enzymes and ligated together. The amino acid translations of the resulting sequences were examined to detect any frame shifts introduced by errors in primer design. Following this verification, the primers were purchased from Invitrogen (Frederick. MD).
[0086] PCR reactions contained 10 pMol of forward and reverse primers, 111.1 of 10 mM DNTPs, 1.5 1 11 of 100 mM MgCl 2 , and 1[11 Proof Pro® Pfu Polymerase in a 50111 reaction with 0.5 pl of 2-40 genomic DNA as the template. PCRs conditions used standard parameters for tailed primers and Pfu DNA polymerase. PCR products were cleaned up with the QIAGEN QIAquick PCR Cleanup kit and viewed in 0.8% agarose gels. Following cleanup and confirmation of size. PCR products and pETBlue2 are digested with appropriate restriction enzymes, usually Ascl and C/a/ at 37° C. for 1 to 4 hours, cleaned up using the QIAquick kit, and visualized in agarose gels. Clean digestions are ligated using T4 DNA ligase for at least 2 hours in the dark at room temperature. Ligations are then transformed into E coli DH5a by electroporation. Transformants are incubated one hour at 37° C. in non-selective media, and then plated onto LB agar containing ampicillin and X-gal. As pETBlue2 carries an Amp r gene and inserts are cloned into the lacZ ORF, white colonies contain the insert sequence. White colonies are picked with toothpicks and patched onto a new LB/Amp/X-gal plate, with three of the patched colonies also being used to inoculate 3 ml overnight broths. Plasmids are prepped from broths which correspond to patched colonies which remained white after overnight outgrowth. These plasmid preps are then singly digested with an appropriate restriction enzyme and visualized by agarose electrophoresis for size confirmation.
[0087] The plasmids are then heat-shock transformed into the Tuner strain, which carries a chromosomal chloramphenicol resistance gene (Cm′). The Transformants are incubated 1 hour at 37° C. in non-selective rescue medium, plated on LB agar with Amp and Cm (Tuner medium) and incubated overnight at 37° C. Any colonies thus selected should contain the vector and insert. This is confirmed by patching three colonies onto a Tuner medium plate and inoculating corresponding 3 ml overnight broths. The next morning the broths are used to inoculate 25 ml broths which are grown to an OD 600 of around 0.6 (2-3 hours). At this point a 1 ml aliquot is removed from the culture, pelleted and resuspended in 1/10 volume 1×SDS-PAGE treatment buffer. This pre-induced sample is frozen at −20° C. for later use in western blots. The remaining broth is then amended to 1 mM IPTG and incubated 4 hours at 37° C. Induced pellet samples are collected at hourly intervals. These samples and the pre-induced control are run in standard SDS-PAGE gels and electroblotted onto PVDF membrane. The membranes are then processed as western blots using a 1/5000 dilution of monoclonal mouse cc-HisTag0 primary antibodies followed by HRP-conjugated goat a-mouse IgG secondary antibodies. Bands are visualized colorimetrically using BioRad's Opti-4CN substrate kit. Presence of His tagged bands in the induced samples, but not in uninduced controls, confirms successful expression and comparison of bands from the hourly time points are used to optimize induction parameters in later, larger-scale purifications.
[0088] Production and Purification of Recombinant Proteins
[0089] Expression strains are grown to an OD 600 of 0.6 to 0.8 in 500 ml or 1 liter broths of tuner medium. At this point a non-induced sample is collected and the remaining culture induced by addition of 100 mM IPTG to a final concentration of 1 mM. Induction is carried out for four hours at 37° C. or for 16 hours at 25° C. Culture pellets are harvested and frozen overnight at −20° C. for storage and to aid cell lysis. Pellets are then thawed on ice for 10 minutes and transferred to pre-weighed falcon tubes and weighed. The cells are then rocked for 1 hour at 25° C. in 4 ml of lysis buffer (8M Urea, 100 mM NaH 2 PO 4 , 25 mM Tris, pH 8.0) per gram wet pellet weight. The lysates are centrifuged for 30 minutes at 15,000 g to pellet cell debris. The cleared lysate (supernatant) is pipetted into a clean falcon tube, where 1 ml of QIAGEN 50% Nickel-NTA resin is added for each 4 ml cleared lysate. This mixture is gently agitated for 1 hour at room temperature to facilitate binding between the Ni +2 ions on the resin and the His tags of the recombinant protein. After binding, the slurry is loaded into a disposable mini column and the flow thru (depleted lysate) is collected and saved for later evaluation. The resin is washed twice with lysis buffer that has been adjusted to pH 7.0; the volume of each of these washes is equal to the original volume of cleared lysate. The flow thru of these two washes is also saved for later analysis in western blots to evaluate purification efficiency.
[0090] At this point the columns contain relatively purified recombinant proteins which are immobilized by the His tags at their C-terminus. This is an ideal situation for refolding, so the column is moved to a 4° C. room and a series of renaturation buffers with decreasing urea concentrations are passed through the column. The renaturation buffers contain varying amounts of urea in 25 mM Tris pH 7.4, 500 mM NaCl, and 20% glycerol. This buffer is prepared as stock solutions containing 6M, 4M, 2M and 1M urea. Aliquots of these can be easily mixed to obtain 5M and 3M urea concentrations thus providing a descending series of urea concentrations in 1M steps. One volume (the original lysate volume) of 6M buffer is passed through the column, followed by one volume of 5M buffer, continuing on to the 1M buffer—which is repeated once to ensure equilibration of the column at 1M urea. At this point the refolded proteins are eluted in 8 fractions of 1/10 th original volume using 1M urea, 25 mM Tris pH 7.4, 500 mM NaCl, 20% glycerol containing 250 mM imidazole. The imidazole disrupts the Nickel ion-His tag interaction, thereby releasing the protein from the column.
[0091] Western blots are used to evaluate the amount of His tagged protein in the depleted lysate, the two washes, and the eluted fractions. If there is an abundance of recombinant protein in the depleted lysate and/or washes it is possible to repeat the process and “scavenge” more protein. Eluate fractions that contain the protein of interest are pooled and then concentrated and exchanged into storage buffer (20 mM Tris pH 7.4, 10 mM NaCl, 10% glycerol) using centricon centrifugal ultrafiltration devices (Millipore). The enzyme preparations are then aliquoted and frozen at −80° C. for use in activity assays.
[0092] In various embodiments of this invention, the cellulose degrading enzymes, related proteins and systems containing thereof, of this invention, for example including one or more enzymes or cellulose-binding proteins, have a number of uses. Many possible uses of the cellulases of the present invention are the same as described for other cellulases in the paper “Cellulases and related enzymes in biotechnology” by M. K. Bhat (Biotechnical Advances 18 (2000) 355-383), the subject matter of which is hereby incorporated by reference in its entirety. For examples, the cellulases and systems thereof of this invention can be utilized in food, beer, wine, animal feeds, textile production and laundering, pulp and paper industry, and agricultural industries.
[0093] In one embodiment, these systems can be used to degrade cellulose to produce short chain peptides for use in medicine.
[0094] In other embodiments, these systems are used to break down cellulose in the extraction and/or clarification of fruit and vegetable juices, in the production and preservation of fruit nectars and purees, in altering the texture, flavor and other sensory properties of food, in the extraction of olive oil, in improving the quality of bakery products, in brewing beer and making wine, in preparing monogastic and ruminant feeds, in textile and laundry technologies including “fading” denim material, defribillation of lyocell, washing garments and the like, preparing paper and pulp products, and in agricultural uses.
[0095] In some embodiments of this invention, cellulose may be used to absorb environmental pollutants and waste spills. The cellulose may then be degraded by the cellulase degrading systems of the present invention. Bacteria that can metabolize environmental pollutants and can degrade cellulose may be used in bioreactors that degrade toxic materials. Such a bioreactor would be advantageous since there would be no need to add additional nutrients to maintain the bacteria—they would use cellulose as a carbon source.
[0096] In some embodiments of this invention, cellulose degrading enzyme systems can be supplied in dry form, in buffers, as pastes, paints, micelles, etc. Cellulose degrading enzyme systems can also comprise additional components such as metal ions, chelators, detergents, organic ions, inorganic ions, additional proteins such as biotin and albumin.
[0097] In some embodiments of this invention, the cellulose degrading systems of this invention could be applied directly to the cellulose material. For example, a system containing one, some or all of the compounds listed in FIGS. 4-11 could be directly applied to a plant or other cellulose containing item such that the system would degrade the plant or other cellulose containing item. As another example, 2-40 could be grown on the plant or other cellulose containing item, which would allow the 2-40 to produce the compounds listed in FIGS. 4-11 in order to degrade the cellulose containing item as the 2-40 grows. An advantage of using the 2-40 or systems of this invention is that the degradation of the cellulose containing plant or item can be conducted in a marine environment, for example under water.
[0098] It is one aspect of the present invention to provide a nucleotide sequence that has a homology selected from 100%, 99%, 98%, 97%, 96%, 95%, 90%, 85%, 80%, or 75% to any of the sequences of the compounds listed in FIGS. 4-11
[0099] The present invention also covers replacement of between 1 and 20 nucleotides of any of the sequences of the compounds listed in FIGS. 4-11 with non-natural or non-standard nucleotides for example phosphorothioate, deoxyinosine, deoxyuridine, isocytosine, isoguanosine, ribonucleic acids including 2-O-methyl, and replacement of the phosphodiester backbone with, for example, alkyl chains, aryl groups, and protein nucleic acid (PNA).
[0100] It is another aspect of some embodiments of this invention to provide a nucleotide sequence that hybridizes to any one of the sequences of the compounds listed in FIGS. 4-11 under stringency condition of 1×SSC, 2×SSC, 3×SSC 1, 4×SSC, 5×SSC, 6×SSC, 7×SSC, 8×SSC, 9×SSC, or 10×SSC.
[0101] The scope of this invention covers natural and non-natural alleles of any one of the sequences of the compounds listed in FIGS. 4-11 . In some embodiments of this invention, alleles of any one of any one of the sequences of the compounds listed in FIGS. 4-11 can comprise replacement of one, two, three, four, or five naturally occurring amino acids with similarly charged, shaped, sized, or situated amino acids (conservative substitutions). The present invention also covers non-natural or nonstandard amino acids for example selenocysteine, pyrrolysine, 4-hydroxyproline, 5-hydroxylysine, phosphoserine, phosphotyrosine, and the D-isomers of the 20 standard amino acids.
[0102] It is to be understood that while the invention has been described above using specific embodiments, the description and examples are intended to illustrate the structural and functional principles of the present invention and are not intended to limit the scope of the invention. On the contrary, the present invention is intended to encompass all modifications, alterations, and substitutions within the spirit and scope of the appended claims.
REFERENCES CITED
[0000]
Andrykovitch, G. and I. Marx (1988). “Isolation of a new polysaccharide-digesting bacterium from a salt marsh.” Applied and Environmental Microbiology 54: 3-4.
Beguin, P. and J. P. Aubert (1994). “The biological degradation of cellulose,” FEMS Microbiol Rev 13(1): 25-58.
Chakravorty, D. (1998). Cell Biology of Alginic Acid degradation by Marine Bacterium 240. College Park, University of Maryland.
Coutinho, P. M. and B. Henrissat (1999). Carbohydrate-active enzyme server. Accessed Jan. 21, 2004 Coutinho, P. M. and B. Henrissat (1999). The modular structure of cellulases and other carbohydrat-active enzymes; an integrated database approach. Genetics, biochemistry and ecology of cellulose degradation . T. Kimura. Tokyo, Uni Publishers Co: 15-23.
[0107] Distel. D. L., W. Morrill, et al. (2002). “Teredinibacter turnerae gen. nov., sp. nov., a dinitrogen-fixing, cellulolytic, endosymbiotic gamma-proteobacterium isolated from the gills of wood-boring molluscs (Bivalvia: Teredinidae).” Int J Syst Evol Microbiol 52(6): 2261-2269.
Ensor, L., S. K. Stotz, et al. (1999). “Expression of multiple insoluble complex polysaccharide degrading enzyme systems by a marine bacterium.” J Ind Microbiol Biotechnol 23: 123-126. Gonzalez, J. and R. M. Weiner (2000). “Phylogenetic characterization of marine bacterium strain 2-40, a degrader of complex polysaccharides.” International journal of systematic evolution microbiology 50: 831-834. Henrissat, B. and A. Bairoch (1993). “New families in the classification of glycosyl hydrolases based on amino acid sequence similarities.” Bichem J 293 (Pt 3): 781-8. Henrissat, B., T. T. Teeri, et al. (1998). “A scheme for designating enzymes that hydrolyse the polysaccharides in the cell walls of plants.” FEBS Lett 425(2): 3524. Jonsson, A. P., Y. Aissouni, et al. (2001). “Recovery of gel-separated proteins for in-solution digestion and mass spectrometry.” Anal Chem 73(22): 5370-7. Kelley. S. K., V. Coyne, et al. (1990). “Identification of a tyrosinase from a periphytic marine bacterium.” FEMS Microbiol Lett 67: 275-280. Kosugi. A., K. Murashima, et al. (2002). “Characterization of two noncellulosomal subunits. ArfA and BgaA, from Clostridium cellulovorans that cooperate with the cellulosome in plant cell wall degradation.” J Bacteriol 184(24): 6859-65. Laemmli, U. K. (1970). “Cleavage of structural proteins during the assembly of the head of the bacteriophage T4 .” Nature 277: 680-685. Ljungdahl, L. G. and K. E. Eriksson (1985). Ecology of Microbial Cellulose Degradation. Advances in Microbial Ecology . New York, Plenum Press. 8: 237-299. Lou, J., K. Dawson, et al. (1996). “Role of phosphorolytic cleavage in cellobiose and cellodextrin metabolism by the ruminal bacterium Prevotella ruminicola.” Apl. Environ. Microbiol. 62(5): 1770-1773. Lynd, L. R., P. J. Weimer, et al. (2002). “Microbial cellulose utilization: fundamentals and biotechnology.” Microbiol Mol Biol Rev 66(3): 506-77, table of contents. Shevchenko, A., M. Wilm, et al. (1996). “Mass spectrometric sequencing of proteins silver-stained polyacrylamide gels.” Anal Chem 68(5): 850-8. Smith, R. D., J. A. Loo, et al. (1990). “New developments in biochemical mass spectrometry: electrospray ionization.” Anal Chem 62(9): 882-99. Stotz, S. K. (1994). An agarase system from a periphytic prokaryote. College Park. University of Maryland. Sumner, J. B. and E. B. Sisler (1944). “A simple method for blood sugar.” Archives of Biochemistry 4: 333-336. Tomme, P., R. A. Warren, et al. (1995). “Cellulose hydrolysis by bacteria and fungi.” Adv Microb Physiol 37: 1-81. Warren, R. A. (1996). “Microbial hydrolysis of polysaccharides.” Annu Rev Microbiol 50: 183-212.
[0125] Whitehead, L. (1997). Complex Polysaccharide Degrading Enzyme Arrays Synthesized By a Marine Bacterium. College Park, University of Maryland.
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The present invention relates to cell wall degradative systems, in particular to systems containing enzymes that bind to and/or depolymerize cellulose. These systems have a number of applications.
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CROSS-REFERENCE TO RELATED APPLICATIONS
Not applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not applicable.
BACKGROUND OF THE INVENTION
1. Field of Invention
This invention relates to a noise abatement system for lowering air velocity in a closed system. Specifically, the invention describes a straight pipe module suppressor, with internal vanes, which reduces the velocity of air used in an industrial airblow cleaning operation.
2. Description of the Related Art
High pressure/high velocity air may be used to clean industrial piping. Reference to cleaning in this application is the process of removing loose and/or lightly adhered debris from piping. The piping to be cleaned may be that which is used in the operation of a power generating plant by providing steam to turbines, in a petrochemical plant to provide stock or product to a process or storage unit, or in any other environment using piping that is typically operated under high pressure and/or high temperature.
The piping to be cleaned may be new fabrication, which may nonetheless contain dirt, sand, loose bolts, used welding rods or other non-structural items or debris left from the fabrication process. Alternatively, the piping to be cleaned may already have been in service and in need of cleaning to remove built-up material (usually scaling) on the interior of the piping. Typically, cleaning of piping that has been in service is accomplished by first flushing the line with a chemical flush to loosen the mill scale, which is solubilized into a solution. The line is then rinsed, and the metal neutralized (washed) to remove the solution containing the chemical flush and the soluble scale particles. The remaining loose or lightly adhered insolubles left in the piping are then removed with the high-pressure air.
Debris from either new fabrication or scaling can damage downstream equipment, such as a turbine, processing unit or other equipment/systems. For example, high pressure impingement of debris on turbine blades operating at high speed could result in damage or catastrophic failure of the turbine.
In a typical pipe cleaning operation, the piping to be cleaned is connected at its upstream end to an air pressurization system, typically a pressure vessel and/or piping, and at its downstream end to a temporary bypass line. The temporary bypass line diverts the high pressure cleaning air away from downstream equipment.
In either use of high pressure air for cleaning piping (new or used), the air pressurization system is typically charged to a level sufficient to provide air pressure through the piping 1.2 times the normal operating pressure of the piping. This high pressure air passes through the piping and is discharged along with the debris out of the piping.
If the high pressure cleaning air, typically traveling at or above sonic speed through the piping, is released directly to the environment without velocity suppression, the noise is intolerable. It is not unusual for such a release to generate noise levels between 115 dB and 140 dB, which can cause hearing loss to those nearby and structural damage or nuisance several miles away. Further, high pressure air can penetrate the skin of a person exposed to the exhaust airflow. This air penetration through the skin can cause air embolisms in the blood vessels, which can be fatal. Thus an air velocity suppression/reduction system is needed in such environments.
Air velocity suppressors for high pressure/high velocity air used to clean piping air are found in the prior art. However, these silencers typically use a baffle system to reduce the velocity of the air. These create unwanted backpressure that reduces the velocity of the air upstream in the cleaning process, thus creating the requirement for higher initial air velocity.
Other air velocity/noise suppressors use a muffling device with a closed cap end, and direct all airflow laterally outward through release holes in the sides of the inner and outer pipes of the suppressor. This system is dangerous when used with high velocity/high pressure stream, since sudden blockage of the release holes, as from a large piece of debris, will cause immediate over-pressurization of the suppressor and likely explosion.
Air suppressor systems used in low velocity applications, such as mufflers used on internal combustion machines or small scale pneumatic silencers on leaf blowers and the like, are unacceptable in high pressure/high velocity air cleaning systems. These low velocity devices, even if scaled up, are unable to adequately reduce the volume and velocity of high-pressure air being exhausted from the system due to their structural and design limitations.
BRIEF SUMMARY OF THE INVENTION
Accordingly, the objectives of this invention are to provide, inter alia, a new and improved air suppression system that:
Does not create undue back pressure;
Does not pose a risk of sudden blockage;
Reduces high air velocity, including those about sonic speed;
Uses standard fabrication components; and
Is cost effective.
These objectives are addressed by the structure and use of the inventive device. A straight through pipe has air directing internal vanes attached to the interior wall of an inside tube. The walls of the inside tube are perforated to permit airflow separated from the main air stream to escape to a space between the inside tube and the outside tube. These vanes cause the high velocity air to rotate about its directional axis. Laminar resistance of the rotation causes a tail of air to form, moving away from the center or core of the exhaust stream and against the interior wall of the inside tube. The high velocity air being released into the inside tube has an exhaust 15 shape shown in FIGS. 6 and 6A, comprising a outer layer 19 and a core 17 . Outer layer 19 is formed as laminar resistance allows side air to move away from the center of exhaust 15 , while the faster air of core 17 speeds through the center of the inner tube 30 . By directing exhaust 15 to rotate about its linear axis, outer layer 19 is “chewed away” as its air is directed into velocity dampening areas between the inside tube 30 and the outside tube 20 of the invention. As outer layer 19 is removed, it is replaced by air from core 16 , thus decreasing the overall velocity of exhaust 15 .
Other objects of the invention will become apparent from time to time throughout the specification hereinafter disclosed.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 depicts a single inventive noise abatement module.
FIG. 2 depicts an inlet view of the single noise abatement module of FIG. 1 .
FIG. 3 depicts an outlet view of the single noise abatement module of FIG. 1 .
FIG. 4 depicts a side view of either a single inlet vane or outlet vane.
FIG. 5 depicts a top view of an inlet vane showing its oblique offset from the axial centerline of the direction of inlet airflow.
FIG. 5A depicts a top view of an inlet vane with no offset.
FIG. 6 a view of the regions of high velocity air as it travels through the inner tube of FIG. 1, cut at line 6 — 6 .
FIG. 6A is a view of the regions of high velocity air as it travels through the inner tube of FIG. 1, cut at line 6 A— 6 A.
FIG. 7 depicts the use of multiple noise abatement modules.
DETAILED DESCRIPTION OF THE INVENTION
The present invention comprises the module shown as noise abatement module 10 , depicted in FIGS. 1, 2 and 3 . Noise abatement module 10 comprises an inside tube 30 that is connected at each end to stubs 24 , which are attached to flanges 40 . Each flange 40 has a flange face 42 and typically flange bolt holes 44 for mating with and bolting to piping and/or other noise abatement modules 10 . Circumferential about inside tube 30 is outside tube 20 , defining annular inside space 33 . Outside tube 20 has outside tube ends 22 that define the inlet and outlet boundaries of inside space 33 between inside tube 30 and outside tube 20 .
An insulating material 34 may be position in space 33 between inside tube 30 and outside tube 20 . When used in noise abatement module 10 , insulating material 34 may be supported in place by expanded material 36 . Expanded material 36 is rigid enough to hold insulating material 34 in place in space 33 , yet is flexible to be shaped around insulating material 34 and inside tube 30 , as well as permeable to air. In the exemplary embodiment, the insulating material is a blanket of insulation, typically fiberglass or kaowool. Also in the exemplary embodiment as expanded material 36 is a sheet of wire mesh 34 , wrapped around the insulation blanket 34 to hold the insulating material 34 in place between the inner wall of outside tube 20 and the outer wall of inside tube 30 .
The diameters of inside tube 30 and outside tube 20 are any that can accommodate the high velocity airflow to be suppressed. In typical applications of noise abatement module 10 being used to abate noise from industrial pipe and vessel air cleaning, inside tube 30 typically has an inner diameter of 30″ to 38″ (76.2 cm to 96.5 cm), and outside tube 20 typically has an inner diameter of 40″ to 54″ (101.6 cm to 147.2 cm).
Inside tube 30 has inside tube perforations 32 , which are typically ⅛″ to ⅜″ (3.2 mm to 15.9 mm) in diameter. In the exemplary embodiment, inside tube perforations 32 are intermediate inlet vanes 50 and outlet vanes 51 .
Inlet vanes 50 are attached to the interior wall of inside tube 30 at the air inlet side 27 . In the exemplary embodiment inlet vanes 50 are six in number and circumferentially equally spaced, as shown in FIG. 2 . As shown in FIG. 4, each inlet vane 50 has a vane base 52 and a vane first end 53 and a vane second end 54 . Vane second end 54 is a trailing end as viewed by the airflow past inlet vane 50 . Airflow travels first past first vane end 53 , past the length of inlet vane 50 , and then past vane second end 54 . Vane base 52 is attached to the interior wall of inside tube 30 , typically with a weld. In an exemplary embodiment where inside tube 30 has a 36″ (91.4 cm) inner diameter, vane base 52 is 8″-16″ (20.3 cm to 40.6 cm), vane first end 54 is 1″-3″ (2.5 cm to 7.6 cm) high, and vane second end 53 is less than ½″ (12.7 mm). As shown in FIG. 5, an inside tube centerline 31 is referenced at each inlet vane 50 , which passes through vane first end 53 and runs parallel with the length of inner tube 30 along the inner wall. Each inlet vane 50 is oriented oblique to an inside tube centerline 31 . In the exemplary embodiment an offset angle 35 is 0.5° to 2.0°. Such an angle results in inlet vane offset A being approximately 0.25″ (6.3 mm) where vane base 52 is 12″ (30.5 cm). Each inlet vane 50 is thus offset obliquely to its own inside tube centerline 31 while remaining normal to the interior wall of inside tube 30 , as depicted in FIG. 2 . While inlet vane 50 is shown in FIG. 5 as a straight vane, alternatively inlet vane 50 can have an arcuate shape (not shown) that results in the same amount of inlet vane offset A as described above for a straight vane.
Outlet vanes 51 are attached to the interior wall of inside tube 30 at the air outlet side 28 . In the exemplary embodiment outlet vanes 51 are four in number and circumferentially equally spaced as shown in FIG. 3 . An exemplary outlet vane 51 is also depicted in FIG. 4 as having the same shape and dimensions as inlet vane 50 when inlet vane 50 is a straight vane. Referring to FIGS. 3, 5 and 5 A, the key difference between outlet vanes 51 and inlet vanes 50 is that outlet vanes 51 each align along an inside tube centerline 31 with no offset A. Each outlet vane 51 is thus aligned with its own inside tube centerline 31 while remaining normal to the interior wall of inside tube 30 .
Referring to FIG. 7, noise abatement module 10 may be used singularly or in conjunction with other noise abatement modules 10 or other systems. For example, noise abatement modules 10 may be aligned in series. Alternatively and additionally, noise abatement modules 10 may include Y-connector 26 to afford parallel alignment as well where the outlet end stub 24 of noise abatement module 10 is joined to the inlet end stub 24 of noise abatement module 10 ′.
OPERATION
Referring to FIGS. 1, 2 , 3 , 6 , and 6 A, noise abatement module 10 is attached to piping or equipment (not shown) from which high pressure air is being exhausted. This is typically accomplished by bolting flange 40 at inlet side 27 to an equipment outlet flange (not shown), thus providing sealed fluid communication between the exhaust air and the interior of noise abatement module 10 . High velocity air enters inside tube 30 through the center opening in flange 40 at inlet side 27 , and is rotated about its linear axis by inlet vanes 50 . This causes outer layer 19 of exhaust 15 to rotate about this linear axis, forcing air into space 33 through inside tube perforations 32 , where it is slowed, and high velocity air from core 17 is allowed to expand and move into outer layer 19 . Thus exhaust 15 is “chewed” until it has less and less high velocity air.
When the exhaust air nears air outlet side 28 , it encounters outlet vanes 51 , which stop the rotation of the exhaust air, baffling even more of the exhaust gas outer layer 19 , and further “chewing” away outer layer 19 . Piping between outlet vanes 51 and the exit flange 40 , typically 24″-48″ (61.0 cm to 121.9 cm) long and including stub 24 and/or a portion of inside tube 30 , acts as a buffer zone to allow the exhaust air to stabilize back to its original linear flow direction.
When used in either or both series and parallel as shown in FIG. 7, each transition through a noise abatement module 10 results in further decrease in the velocity of the air and its attendant noise. The air is finally exhausted to the atmosphere or additional air directing equipment, such as an upward plenum.
The foregoing disclosure and description of the invention is illustrative and explanatory thereof. Various changes in the details of the illustrated construction may be made within the scope of the appended claims without departing from the spirit of the invention. The present invention should only be limited by the following claims and their legal equivalents.
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The current invention is device for lowering the air velocity and inherent noise of high-speed air released from a closed system, comprising a straight pipe module with an outer tube and a concentric inner tube creating an annular space therebetween. The inner tube has interior fins at the inlet, which initiate rotation in an airflow directed therethrough, and interior fins at the outlet, which arrest the airflow rotation. Perforations along the length of the inner tube, from inlet fins to outlet fins, permit the release of a turbulent outer zone of the airflow, permitting the high velocity core of the airflow to expand and slow, reducing the noise of the airflow.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention is directed to the vapor phase formation of compound semiconducting films in general and particularly to the formation of indium phosphide and gallium phosphide films on single crystal substrates.
2. Description of the Prior Art
Compound semiconductor films in general have been used extensively in various electronic devices as, for example, the fabrication of laser diodes, microwave oscillators and photoelectric detectors. In microwave applications, thin film semiconductors are required for high frequency response characteristics.
Semiconductor quality InP epitaxial thin films have been deposited via Chemical Vapor Deposition (CVD) (R. C. Clarke, B. D. Joyce and W. H. E. Wilgoss, Solid State Communications, Vol. 8, p. 1125, 1970) and Liquid Phase Epitaxy (LPE) (J. L. Shay, K. J. Bachmann and E. Buehler, Appl. Phys. Lett., Vol. 24, p. 192, 1974). However, these techniques require temperatures above 500° C. For some applications, lower substrate temperatures are required. For example, substrate decomposition limits the substrate temperature for certain heterojunction photoelectric devices. Specifically, a terrestrial solar cell incorporating InP deposited on CdS would have a potentially high energy conversion efficiency (Sigurd Wagner, J. L. Shay, K. T. Bachmann, E. Buehler, Appl. Phys. Lett., Vol. 26, p. 229, 1975), but fabrication of such a device would have to be accomplished below approximately 400° C to avoid CdS decomposition. Another application involving lower substrate temperatures would be abrupt junction microwave devices such as InP Gunn Effect devices. In this instance, lower temperatures would alleviate interdiffusion effects.
Molecular beam techniques have been used successfully by various workers (A. Y. Cho, J. of Vacuum Science and Technology, Vol. 8, p. 531, 1971; D. L. Smith and V. Y. Pickhardt, J. of Appl. Physics, Vol. 46, p. 2366, 1975) for the deposition of semiconductor epitaxial films at low temperatures. However, problems arise with this technique in producing the appropriate phosphorus vapor species (C. T. Foxon, B. A. Joyce, R. F. C. Farrow and R. M, Griffiths, J. Phys. D., Vol. 7, p. 2422, 1974) for InP deposition. Additionally, this technique severely limits the uniform deposition area and therefore is not scalable. This arises because two sources are used. These sources are at two different temperatures and, therefore, must be thermally isolated from each other. This isolation requirement leads to the limited uniformity in the deposited films (see U.S. Pat. No. 3,615,931 by J. R. Arthur et al).
Reactive evaporation techniques have been used to deposit polycrystalline semiconductor compounds on single crystal substrates. (F. J. Morris et al, J. Vac Sci. Technol., Vol. II, No. 2, page 506, March 1974.) However, films deposited via this technique were neither single crystal films nor of high purity and therefore were not of semiconductor quality. The techniques disclosed by Morris et al. are not readily scalable and fail to control sources of impurities during the deposition process.
There are no prior art processes known to me which facilitate the simultaneous production of high purity semiconductor quality films at low processing temperatures by a scalable method.
THE INVENTION
Summary
Objectives of this invention are: to deposit heteroepitaxially semiconductor quality (≦ 5 ppm impurity content) thin (≦ 5 μ) films; to deposit these films on substrates at relatively low temperatures (≦ 500° C); to deposit these films at economical rates (˜5 μ/hour); and to deposit these films in a fasion amenable to eventual production scales.
In meeting these objectives, a novel scalable vapor phase deposition apparatus and method for the preparation of compound semiconductor (MX) films which meets all of the above-listed objectives while avoiding the pitfalls of prior art processes has been developed.
The key to this process lies in the development of a method for controlling the production of M and X component vapors. This method was rendered feasible with the development of a novel source design for the production of M and X component vapors. This source consists of a perforated dish made from an inert material with a hollow cavity into which an X component hydride gas is introduced. X may be any element from Group V or VI of the Periodic Table.
The M component (a metal from Group II or III of the Periodic Table) is placed in the perforated dish and elevated to a temperature suitable for evaporation of the metal component and the dissociation of the X hydride gas into X vapors and hydrogen gas. The metal vapor pressure and the X component vapor pressure are controlled independently by the cavity temperature and an X hydride metering value.
This source is placed in a chamber pumped by a turbomolecular pump to ensure removal of unreacted hydrogen gas and other residual impurities. The source and substrate region is surrounded by a liquid nitrogen cooled shroud which also aids in reducing residual impurity gas pressures. This shroud effectively forms an inner source substrate deposition chamber providing an improved impurity level deposition region.
BRIEF DESCRIPTION OF THE DRAWINGS
The nature or scope of this invention may be readily understood by reference to the drawings where
FIG. 1 is a schematic line drawing of the Planar Reactive Evaporative Deposition Apparatus,
FIG. 2 is an expanded plan view of the preferred Inner Source Substrate Deposition Chamber, and
FIG. 3 is an expanded plan view of an alternative design for the MX source chamber.
DESCRIPTION OF THE INVENTION
MX compounds, where M is a metal taken from Groups II and III of the periodic table and X is an element taken from Groups V and VI of the periodic table, have utility in the preparation of semiconducting films. Thin films comprised of single crystal MX compounds coated onto single crystal substrates are exceedingly difficult to prepare and are very costly. This is particularly true of those MX compounds which decompose at elevated temperatures with high X component vapor pressures. Notable examples of such compounds are InP, GaP, and CdS. A large part of the difficulty in preparing such films is attributed to the problems associated with handling the X component vapor species of the MX compound.
In order to facilitate the handling of X component vapor species, a reactive evaporative deposition technique has been devised in which the X component is introduced into the deposition environment via X hydride decomposition. Two immediate advantages of this technique are the ease of control of the X component vapor species and source scalability. The control of X component vapor pressure allows independent adjustment of the X component to M component pressure ratio which facilitates the production of stoichiometric films. Since the source is planar, it is scalable and therefore large substrate areas may be coated. This facilitates large production rates.
The ability to control the component vapor pressures allows the deposition of MX compounds at a lower rate which favors lower deposition substrate temperatures. Temperatures on the order of 350° C and less than 500° C have been shown to be adequate when the deposition rate is less than 5 μ/hour. Chemical Vapor Deposition techniques, in contrast, generally involve deposition rates on the order of 50 μ/hour and therefore require epitaxial temperatures about 500° C.
High purity films are obtained by operating with residual gas pressures of less than 10 -9 torr. Such low pressures are obtained by operation in a high vacuum chamber (<10 -8 torr) and employing a liquid nitrogen cooled shroud to create an inner source substrate deposition chamber.
Thin films are prepared by the technique described above by utilizing a planar reactive evaporative apparatus as shown in FIG. 1. The essential features of this apparatus are: a vacuum chamber enclosure 10 fabricated from metal in accordance with conventional vacuum technologies; an X component hydride inlet line 11 fabricated from stainless steel equipped with a metering valve 12 which serves to control the X component introduction rate into an inner source substrate deposition chamber 13. A rotatable substrate mounting plate 14 fabricated from molybdenum is mounted above the deposition chamber 13 on plate support bearings 15, mounted on the inner walls of the vacuum chamber enclosure 10.
Rotation of the substrate plate 14 is manually accomplished via a bellows sealed rotating feedthrough 16 which extends through the chamber lid 17.
Substrates to be coated are mounted on the substrate plate 14 and heated via substrate heater lamps 18 mounted in a heater chamber 19 attached to the inner surface of the chamber lid 17.
The vacuum chamber 10 is connected to a turbomolecular pump 20 used to maintain a high vacuum and remove residual gases. A residual gas analyzer 21 is used to monitor the impurity gas levels within the chamber 10.
A dopant source oven 22 is mounted below the inner source substrate deposition chamber 13 on an inlet feedthrough line 23 which extends through the vacuum chamber base plate 24 and connects to the metering valve 12 which controls the flow of X component hydride gas from the hydride inlet line 11.
A more detailed drawing of the inner source substrate chamber 13 and the dopant source oven 22 is shown in FIG. 2. Here, X component hydride gas flowing through the inlet feedthrough line 23 passes through the dopant source oven 22. The dopant source oven 22 is fabricated from molybdenum or tantalum. The temperature of the oven 22 is controlled by heater coils 30 wrapped about its periphery and monitored by a thermocouple not shown.
The dopant 32 in the dopant source oven 22 is vaporized and carried by an X component hydride gas stream into the source cavity 33 via a source cavity inlet tube 34.
The walls and the bottom surface of the source cavity 33 are composed of ultra pure alumina, graphite, or boron nitride. The source cavity 33 is electrically insulated from a graphite heater plate 35 by non-conducting insulator spacers 36. The graphite heater plate 35 is electrically heated by current which flows between water cooled copper electrodes 37. Electrical coupling between the heater plate 35 and the copper electrodes 37 is accomplished via a liquid gallium coupling 38.
The source cavity 33 is equipped with a perforated sapphire top plate 39 which serves to direct M, X, and H 2 vapor streams towards the substrates to be coated.
The temperature of the M component of the MX compound 40 contained in the bottom of the source cavity 33 is monitored by a tantalum sheathed thermocouple 41.
Refractory metal heat shields 42 surround the source cavity 33 and thermally isolate the source cavity 33 and heater plate 35 from a cooled metallic shroud 43. The shroud 43 provides a condensation surface protecting the inner deposition chamber 13 from residual gas impurities present in the outer vacuum chamber 10. Further protection against residual gases entering the deposition chamber is obtained by an optically dense metal baffle 44 mounted onto the top of the shroud 43. The metal baffle 44 is sized such that the distance between it and the substrate mounting plate 14 is minimal.
Coolants for the shroud 43 and an electrical current for the water cooled copper electrodes 37 are provided from a side port 45 located in the vacuum chamber wall 10.
An alternative source cavity design is shown in FIG. 3. This source design differs from that of 33 in FIG. 2 in that it operates with the M vapor in a free evaporative condition. The Knudson source design of FIG. 2 operates with the M component vapor pressure in the equilibrium condition.
The above-described apparatus is used to prepare compound semiconducting films in general as follows: single crystal substrates 46 to be coated are mounted on the substrate mounting plate 14 and placed in the vacuum chamber 10 on the plate support bearings 15 mounted on the inner wall of the vacuum chamber. The standard sample load configuration consists of several samples in each of three of the four substrate plate quadrant positions. The fourth quadrant position contains a blank plate. Initially, this blank position is centered above the source chamber for source bakeout. The loding and unloading of samples is done in flowing dry nitrogen or argon gas to reduce the water vapor build-up on the chamber walls.
The source and dopant chambers will have been previously loaded with a suitable M component and dopant.
The apparatus is closed and evacuated to <10 -8 torr with the turbomolecular pump 20. The use of a turbomolecular pump instead of a diffusion pump is necessary to maintain an oil-free system, and also to allow good pumping speeds even at moderate chamber pressures. This follows because even an adequately trapped diffusion pump should be throttled down at pressures above 3 × 10 - 4 torr to avoid oil vapor back-streaming.
The substrate heaters 18 are activated and the substrate plate 14 temperature is raised to a temperature between the film epitaxial temperature and substrate decomposition temperature. The source temperature is then raised to approximately 100° C below the temperature at which the M component vapor pressure becomes appreciable but above the decomposition temperature of the X component hydride. The source temperature and substrate plate temperature are held at these values until residual gases are baked out of the inner deposition chamber and the pressure restabilizes. The pressures of the various residual gases are monitored with the residual gas analyzer 21.
The temperature of the shroud is lowered by the introduction of a liquid coolant (preferably liquid nitrogen). This step provides for a reduction of residual gas impurities within the chamber 10. The substrate samples 46 may now be cleansed of any oxide surface coatings by thermally baking them either in an ultra high vacuum or in the presence of an X component vapor species and hydrogen gas. The cleansing method utilized will vary as a function of substrate material composition.
In the case of InP P films deposited epitaxially on InP single crystals, removal of the oxide surface coating is accomplished by heating the InP substrates in the presence of phosphorus vapors and hydrogen gas.
In the case of InP films deposited epitaxially on CdS single crystals, removal of oxide surface coatings may be accomplished by thermally baking the CdS substrates in a high vacuum.
Once the shroud has been cooled and the system stabilized, the metering valve 12 is opened to allow X component hydride gas to enter the source chamber 33. When the pressure within the chamber stabilizes, the source temperature is increased to a value such that the M component vapor pressure reaches the desired level and deposition begins.
Dopants may be provided via one of two methods. The first method would involve placing a solid dopant source in the dopant oven 22 and raising the temperature of the oven to a predetermined level for the desired dopant concentration during the deposition on the blank substrate quadrant. In the second case the dopant may be premixed with the X component hydride and introduced with the X component hydride when the metering valve is opened.
The deposition rate is a function of the source temperature. Source cleaning is continued on the blank sample position for a brief period and then the samples are rotated into position in succession for deposition.
Specific control parameters for the use of this apparatus and method to prepare InP films are shown below: In the source chamber, the M component is In and the X component hydride is phosphine (PH 3 ). Substrate temperatures of 350°-400° C are employed. The source temperature is initially raised to 700° C for bakeout. This temperature exceeds the decomposition temperature of PH 3 . A needle valve setting sufficient to yield a hydrogen plus phosphorus vapor pressure within the chamber of 3 × 10 -4 torr and a source temperature of 900° C give a deposition rate of 2 μ/hr.
Extension to materials other than InP is accomplished as follows: a straightforward substitution of Ga for In would allow GaP deposition, and a further substitution of AsH.sub. 3 gas for PH 3 gas would allow the deposition of InAs and GaAs. Similarly, substituting CdS for In and H 2 S for PH 3 would allow CdS deposition and likewise for other II-IV or IV-VI materials. The method is most useful for the deposition of stoichiometric compound semiconductor films in which one of the species in the compound is quite volatile.
Although in the above description pure X component hydride gases were introduced through the metering valve, it is also possible to use mixtures of X component hydride gas and hydrogen gas. In this instance, the extra hydrogen gas would act as a carrier gas and provide a reducing atmosphere in the deposition chamber. This would allow a reduction of oxygen impurities incorporated in the growing films.
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An apparatus and method for epitaxial film formation is disclosed. Planar reactive evaporation techniques suitable for scaling are employed to produce high purity compound semiconducting films at relatively low temperatures.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to piston type compressors, more particularly, to piston type compressors having a cam plate.
2. Description of the Related Art
A typical piston type compressor is described below. This type or compressor includes a pair of cylinder blocks secured to each other. A front housing is coupled to the front end of the front cylinder block with a valve plate arranged in between. In the same manner, a rear housing is coupled to the rear end of the rear cylinder block with a valve plate arranged in between. A crank chamber is defined between the cylinder blocks. Further, suction and discharge chambers are defined in each housing. The cylinder blocks also include a plurality of cylinder bores and a suction passage defined therein. A double-headed piston is reciprocally housed in each cylinder bore. The valve plates are provided with a plurality of suction ports each corresponding to one of the cylinder bores. Each suction port is selectively opened and closed with a suction valve flap.
As each piston is reciprocated in the associated cylinder bore, refrigerant gas is drawn from an external refrigerant circuit into the crank chamber. The gas is then supplied to the suction chambers in the front and rear housings by the suction passage. The gas in the suction chambers is drawn into each cylinder bore through the corresponding suction port.
In the above described prior art piston compressor, each suction port is arranged on the corresponding cylinder bore at the same position with respect to the center of the valve plate. Further, all the suction valve flaps are arranged extending in the same direction with respect to the rotating direction of the drive shaft. The recent trend of increasing in the number of cylinder bores has resulted in an increased ratio of the cross-sectional area of cylinder bores to the cross-sectional area of the cylinder block. This results in a reduced cross-sectional area for forming suction passages. It is thus difficult to form the same number of suction passages as the number of cylinder bores. In other words, it is difficult to form suction passages so that each corresponds to one cylinder bore.
In a compressor having the above described construction, the pressure in each suction chamber varies from one location to another. This causes the pressure in a cylinder bore close to a suction passage to be different from the pressure in a cylinder bore far from the suction passage. The variation of suction pressures in the cylinder bores is referred to as suction pressure loss. Suction pressure loss results in unstable compression operation.
When low pressure refrigerant gas is drawn into a cylinder bore, the compression ratio needs to be relatively high for compressing the gas to a predetermined discharge pressure. In the state, the compressor takes more time until the refrigerant gas is discharged from a compression chamber. Consequently, the amount of discharge gas is decreased in accordance with the delay of discharging timing for operating the compressor. In short, the variation of the pressure in the suction chambers results in an increased power loss. Further, the temperature of the discharged gas is increased. Thus, the refrigerant capacity of the external refrigerant circuit is degraded.
Further, if a cylinder bore draws lower pressure refrigerant gas, the cylinder bore has a low suction pressure. The cylinder bore therefore draws less refrigerant gas from the external refrigerant circuit. This lowers the flow rate of the refrigerant gas in the circuit thereby increasing the pressure in the evaporator. The elevated pressure in the evaporator degrades the refrigerant capacity of the circuit.
SUMMARY OF THE INVENTION
Accordingly, it is an objective of the present invention to provide a piston type compressor that has an improved refrigerant capacity.
Another objective of the present invention is to provide a piston type compressor that operates stably.
To achieve the foregoing and other objectives and in accordance with the purpose of the present invention an improved piston type compressor having a cylinder block is provided. The cylinder block includes a plurality of cylinder bores and a plurality of suction passages. Each suction passage extends through the cylinder block to connect a crank chamber with a suction chamber. The suction chamber is connected with the cylinder bores by way of a plurality of suction ports. Each suction port Is located in association with each of the cylinder bores. Each cylinder bore accomnmodates a piston that moves therein to circulate gas between the compressor and an external gas circuit. The gas introduced into the crank chamber from the external gas circuit is supplied to the suction chamber through each suction passage. The gas is supplied from the suction chamber to each cylinder bore through an associated suction port. The suction passages are smaller in number than the cylinder bores. Each suction bore is disposed In the vicinity of an opening of the suction passage.
Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principals of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention, together with objects and advantages thereof, may best be understood by reference to the following description of the presently preferred embodiments together with the accompanying drawings.
FIG. 1 is a cross-sectional view showing a double-headed piston type compresses According to a preferred embodiment of the present invention;
FIG. 2 is a cross-sectional view taken along line 2--2 of FIG. 1;
FIG. 3 is a cross-sectional view illustrating a lubricating mechanism in the compressor of FIG. 1; and
FIG. 4 is a cross-sectional view taken along line 4--4 in FIG. 3.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
A first embodiment of the present invention will now be described with reference to the drawings. Although the present invention Is embodied in a double-headed piston type compressor in the following description, it should be apparant to those skilled in the art that the present invention may also be embodied in single-headed type compressors.
As shown in FIGS. 1 and 2, a pair of cylinder blocks 11, 12 are coupled to each other. A front housing 13 is coupled to the front end of the front cylinder block 11 with a metal valve plate 14 arranged in between. In the same manner, a rear housing 15 is coupled to the rear and of the cylinder block 12 with another metal valve plate 14 arranged in between.
Five bolt holes 16, 17, 18 extend between the front housing 13 and the rear housing 15. Each of the bolt holes 16, 17, 18 extends through the front housing 13, the front valve plate 14, the cylinder blocks 11, 12, the rear valve plate 14, and the rear housing 15. The holes 16, 17, 18 are arranged on the same circumference, that is, at the same distance form the center of the plate 14, and are spaced equally apart. A bolt 19 is inserted into each of the bolt holes 16, 17, 18 from the front housing 13 and screwed into a threaded hole 20 provided in the rear housing 15. The bolts 19 fasten the front housing 13 and the rear housing 15 to the cylinder blocks 11, 12 with the valve platen 14 arranged in between.
Each of the cylinder blocks 11, 12 and the front housing 13 has a shaft hole defined in the center portion. A drive shaft 21 is rotatably supported in the shaft holes by a pair of radial bearings 22A, 22B, which are provided in the shaft hole of the front cylinder block 11 and in the shaft hole in the rear cylinder block 12, respectively. The rear end of the whaft hole of the roar housing 12 is closed with a cap member 47. A lip seal 23 is arranged in the shaft hole of the front housing 13 between the periphery of the front end of the drive shaft 21 and the shaft hole. The drive shaft 21 is operably connected to an external drive source such as a vehicle engine by a clutch mechanism (not shown). Connection of the clutch mechanism transmits the drive force of the external drive source to the drive 5haft 21 and rotate the whaft 21.
Five cylinder bores 24 extend through the cylinder blocks 11, 12 parallel to the axis of the drive shaft 21. The cylinder bores 24 are spaced equally apart from one another along a circle that is coaxial with the drive shaft 21. A double-headed piston 25 is reciprocally accommodated in each cylinder bore 24. In each cylinder bore 24, a front compression chamber 26 is defined between a front head of the piston 25 and the associated front valve plate 14, while a rear compression chamber 26 is defined between the rear head of the piston 25 and the associated rear valve plate 14.
A crank chamber 27 is defined between the cylinder blocks 11, 12. A swash plate 28 is fixed to the drive shaft 21 in the crank chamber 27. The peripheral portion of the swash plate 28 is connected to the middle of each piston 25 by means of shoes 29. The rotation of the drive shaft 21 causes the swash plate 28 to reciprocate each piston 25.
A pair of thrust bearings 30 are arranged between the front side of the swash plate 28 and the cylinder block 11 and between the rear side of the swash plate 28 and the cylinder block 12. The swash plate 28 is held between the cylinder blocks 11, 12 with the thrust bearings arranged in between. When the compressor is operating, the thrust bearings 30 transmit compression reactive force in the thrust direction acting on the swash plate 28 to the cylinder blocks 11, 12.
As shown in FIGS. 1 and 3, a substantially annular auction chamber 31 is defined in the peripheral portion of the front and rear housings 11, 12. As shown in FIG. 2, the bolt hole 17 is located in the vicinity of the bottom of the cylinder blocks 11, 12 and the bolt hole 18 is located in the vicinity of a discharge passage 33, which will be discussed later. The rest of the bolt holes that is, the bolt holes 16, also serve as suction passages. The number of the suction passage is three and is less than the number of the cylinder bores 24, which is five in this embodiment.
The bolt holes 16, which also function as auction passages, have a substantially triangular cross-section. The cross-section area of each hole 16 is sufficiently larger than the cross-sectional area of the bolts 19. The inner ends of the passages 16 are connected to the crank chamber 27, while the outer ends are connected to the front and rear auction chambers 31. Refrigerant gas in drawn into the crank chamber 27 from an external refrigerant circuit (not shown). The gas in the chamber 27 is then led to the suction chambers 31 through the suction passages 16.
An annular discharge chamber 32 is defined in the center portion of the front and rear housings 13, 15. A discharge passage 33 extends through the cylinder blocks 11, 12 and connects the front and rear discharge chambers 32. A discharge muffler 34 is provided at the upper peripheral section of the rear cylinder block 12. The muffler 34 is communicated with the discharge passage 33 by a bore 35. Refrigerant gas in the front and rear discharge chambers 32 is discharged to the external refrigerant circuit (not shown) via the discharge passage 33, the bore 35 and the discharge muffler 34.
The bolt hole 12 is located in the vicinity of the discharge passage 33. The diameter of the hole 18 is substantially the same as the diameter of the bolts 19. The hole 18 thus functions only to accommodate the associated bolt 18 but does not function as a suction passage.
A suction valve mechanisms 36 are provided between the valve plates 14 cylinder blocks 11, 12. When the pistons 25 reciprocate, the suction valve mechanisms 36 allow refrigerant gas in the suction chambers 31 to be drawn into each compression chamber 26. Discharge valve mechanisms 37 are provided between the valve plate 14 and the front and rear housings 13, 15, respectively. When the pistons 25 reciprocate, the discharge valve mechanisms 37 allow refrigerant gas that is compressed In the compression chamber 26 to be discharged to the discharge chambers 32.
The structure of the suction valve mechanism 36 and the structure of the discharge mechanism 37 will hereafter be described. As shown in FIGS. 1 to 3, the valve plate 14 includes suction ports 38 and discharge ports 39 defined therein. Each intake port 38 and each discharge port 39 correspond to one of the cylinder bore 24. Each suction port 38 is located in the vicinity of one of the suction passages 16, and the same distance exists between each port 38 and the opening of the corresponding passage 16. The discharge ports 39 are located in the vicinity of the center of the valve plate 14.
Each intake valve mechanism 36 includes a metal plate 40 having five suction valve flaps 40a. Each flap 40a corresponds to one of the emotion ports 38 and closes and opens the corresponding suction port 38. Each valve flap 40a extends along the diameter of the associated cylinder bore 24 toward the adjacent suction passage 16 with its distal aligned with the inner periphery of the corresponding cylinder bore 24.
Each discharge valve mechanism 37 includes a metal plate 41, which functions as valve flaps, and a metal retainer plate 42, which also functions as a gasket. Both sides of the retainer plate 42 are coated with rubber. The plate 41 has five discharge valve flaps 41a, each corresponding to one of the discharge ports 39. The retainer plate 42 has retainers 42a for defining the opening of the discharge valve flaps 41a.
As shown in FIGS. 1, 3 and 4, a cyclone type oil separating chamber 43 is defined in the discharge muffler 34. The chamber 43 is communicated with a first oil storing chamber 44 defined next to the chamber 43. Refrigerant gas in the discharge chambers 32 is drawn into the oil separating chamber 43 through the discharge passage 33 and the bore 35. The gas is then rotated along the inner wall of the chamber 43. The centrifugal force of the gas rotation separates lubricant oil from the refrigerant gas. The separated lubricant oil is stored in the first oil storing chamber 44.
A second oil storing chamber 45 is defined in the center portion of the rear housing 15 and in the rear portion of the shaft hole of the rear cylinder block 12. The chamber 45 is communicated with the first oil storing chamber 44 by a restricting passage 46. The passage 46 leads lubricant oil in the first oil storing chamber 44 to the second oil storing chamber 45. Part of the lubricant oil in the chamber 45 is supplied to the rear radial bearing 22B through a lubricant passage 48 formed in the cap member 47 and lubricates the bearing 22B.
A first oil groove 49 is formed on the rear end face of the cylinder block 12. The upper end of the groove 49 is communicated with the second oil storing chamber 45 and the lower end is communicated with the bolt hole 17, which is defined in the bottom portion of the cylinder blocks 11, 12. A second oil groove 50 is formed on the front end face of the cylinder block 11. The upper end of the groove 50 is communicated with the front end of the shaft hole of the cylinder block 11 and the lower end is communicated with the bolt hole 17.
The bolt hole 17 has a larger diameter than that of the bolt 19 and functions as a lubricant passage that is disconnected from the crank chamber 27. The lubricant oil in the second oil storing chamber 45 is supplied to the front radial bearing 22A by the first oil groove 49, the bolt hole 17, which functions as a lubricant passage, and the second oil groove 50 and lubricates the bearing 22A and the lip seal 23.
The operation of the above described double-headed piston type compressor will hereafter be described.
When the drive shaft 21 is rotated by the external drive source such as a vehicle engines the rotation of the shaft 21 causes the swash plate 28 to rotate therewith. The rotation of the swash plate 28 is converted to linear reciprocation of each piston 25 in the associated bore 24. The reciprocation of each piston 25 draws refrigerant gas in the external refrigerant circuit (not shown) into the crank chamber 27. The gas in the crank chamber 27 is then led to the front and rear suction chambers 31 by the suction passages 16. A movement of each piston 25 from the top dead center to the bottom dead center opens the corresponding suction valve 40a thereby drawing the gas in the suction chambers 31 into the compression chamber 26 defined in the cylinder bore 24 through the intake port 38. The movement of the piston 25 from the bottom dead center to the top dead center compresses the gas in the compression chamber 26 until the pressure of the gas reaches a certain level. The compressed gas causes the discharge valve flap 41a to flex to open and is discharged to the discharge chamber 32 through the corresponding discharge port 39. The discharge passage 33 and the bore 35 lead the gas in the discharge chamber 32 to the discharge muffler 34. The oil separating chamber 43 in the muffler 34 separates lubricant oil from the refrigerant gas with centrifugal force. The residual gas is supplied to the external refrigerant circuit.
The lubricant oil that is separated from the refrigerant gas in the separating chamber 43 is led to the second oil storing chamber 45 through the first oil storing chamber 44 and the restricting passage 46. The oil is temporarily stored in the second chamber 45. The lubricant oil in the chamber 45 is supplied to the rear radial bearing 22B by the passage 48 and is also supplied to the front radial bearing 22A by first oil groove 49, the lubricant passage 17 and the second oil groove 50.
In this compressor, the number of the suction passages 16 is less than the number of the cylinder bores 24. Each suction port 38 is formed close to one of the suction passages 16. In other words, the distance between each suction port 38 and the corresponding suction passage 16 is short. This lowers the flow resiatence when refrigerant gas in the suction chamber 31 is drawn into each cylinder bore 24 through the corresponding suction port 38. Further, refrigerant gas is directly drawn into the cylinder bores 24 from the suction passages 16 through the suction ports 38. This suppresses differences of suction pressure (suction pressure loss) among the cylinder bores 24. The compression of the compressor is thus stabilized. Also the efficiency of the suction of refrigerant gas into the cylinder bores 24 is enhanced. The amount of refrigerant gas drawn into the crank chamber 27 from the external refrigerant circuit is increased, accordingly. Further, the pressure in a particular cylinder bore 24 is prevented from being significantly higher than that of the other bores 24. This lowers power loss and improves the refrigerant capacity of the compressor. The compression efficiency is thus further improved.
Each suction valve flap 40a extends toward and is directed to one of the suction passages 16. This facilitates the opening of the suction valve flaps 40a in the cylinder bores 24. This further lowers flow resistance and suction pressure loss. Also, the efficiency of suction of refrigerant gas into the cylinder bores 24 is further improved.
Each suction valve flap 40a extenda along the diameter of the corresponding cylinder bore 24 with the proximal end aligned with the inner circumference of the corresponding cylinder bore 24. This ensures that the length of each flap 40a is sufficient thereby facilitating the opening of the flaps 40a. The efficiency of suction of refrigerant gas into the cylinder bores 24 is thus further improved.
The five bolt holes 16, 17, 18 are formed in the cylinder blocks 11, 12 to accommodate the bolts 19. Among the holes 16 to 18, the three bolt holes 16 also function as the suction passages. This helps to maximize the cross-sectional area of the cylinder blocks 11, 12. Further, the bolt hole 17, which does not function as a suction passage, can be utilized as a lubricant passage.
The bolt holes 16 are formed to function as suction passages, but the bolt hole 17, which is located in the bottom portion of the cylinder blocks 11, 12, is not formed to function as a suction passage. The bolt hole 17 can therefore be utilized as a lubricant passage. This facilitates supply of lubricant oil to the front and rear radial bearings 22A, 22B and the lip seal 23.
The bolt holes 16 arc formed to function as suction passages, but the bolt hole 18, which is located in the vicinity of the discharge passage 33, is not formed to function as a suction passage. This ensures a long distance between the suction passages 16 and the discharge passage 33 thereby improving the sealing between the passages 16 and 33, which have pressures that greatly differ. Accordingly, gas leakage between the passages 16 and 33 is prevented. Consequently, the compression efficiency of the compressor is improved.
Although only one embodiment of the present invention has been described herein, it should be apparent to those skilled in the art that the present invention may be embodied in many other specific forms without departing from the spirit or scope of the invention. Particularly, it should be understood that the invention may be embodied in the following forms.
(1) The holes 16 may function solely as bolt holes and suction passages may be formed at different locations from the holes 16.
(2) Contrary to tho preferred embodiment, the suction chambers 31 may be defined in the center portion of the housings 13, 15 and the discharge chambers 32 may be formed in the peripheral portion of the housings 13, 15.
(3) The number of the holes 16, which function as suction passages and bolt holes, may be changed. For example, two or four holes 16 may be formed in the pair of cylinder blocks.
(4) The present invention may be embodied in double-headed piston type compressors having different numbers of cylinders from the preferred embodiment. For example, the invention may be embodied in compressors having 2, 4, 6, 8 or 12 cylinders,
(5) The present invention may be embodied in other types of compressors that include double-headed pistons or single-headed pistons. For example, the invention may be embodied in wave cam plate type compressors.
Therefore, the present examples and embodiments are to be considered as illustrative and not restrictive and the invention is not to be limited to the details given herein, but may be modified within the scope and equivalence of the appended claims.
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An improvement of a piston type compressor is disclosed. The compressor has a cylinder block that includes a plurality of cylinder bores and a plurality of suction passages. Each of the suction passages extends through the cylinder block to connect a crank chamber with a suction chamber. The suction chamber is connected with the cylinder bores via a plurality of suction ports located in association with the cylinder bores. Each cylinder bore accommodating a piston that moves therein to circulate gas between the compressor and an external gas circuit. The gas introduced into the crank chamber from the external gas circuit is supplied to the suction chamber through each suction passage and is supplied from the suction chamber to each cylinder bore through an associated suction port. The suction passages are smaller in number than the cylinder bores. The suction ports are disposed in the vicinity of an opening of the suction passages.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority from provisional application Ser. No. 60/388,606 filed Jun. 13, 2002.
FIELD OF THE INVENTION
[0002] This invention relates to a composition and method of using compositions of alkyl esters of lactic acid as non-toxic, environmentally friendly disinfectants of solid substrates. The disinfectants are usable in a variety of contexts without corroding or chemically attacking the material in such surfaces.
BACKGROUND OF THE INVENTION
[0003] Environmental surface disinfectants are useful for removing pathogens on inanimate surfaces in a variety of settings. In household settings, environmental surface disinfectants are useful to prevent the transmission of pathogens from surfaces in the kitchen and bathroom, among others. In medical settings, environmental surface disinfectants are useful for removing pathogens from reusable patient-care equipment and other surfaces contacted by patients. In recreational settings, environmental surface disinfectants are useful to prevent the transmission of pathogens by recreational equipment, such as scuba gear.
[0004] A variety of environmental surface disinfectants are known in the art. Triclosan is perhaps the most common environmental surface disinfectant for household use. However, there is public concern regarding its chemical similarity to dioxins, which are known to harmful to human health.
[0005] Alcohols, such as isopropyl ethyl alcohol, are also widely used as environmental surface disinfectants. Although alcohols are well known in the art for their wide germicidal activity, alcohols evaporate rapidly, making extended contact times difficult to achieve. This factor precludes the practical use of alcohols as large surface disinfectants. Another disadvantage is that alcohols must be used at very high concentrations, usually between 70-95% concentration, for effectiveness.
[0006] Halogens, such as iodine or chlorine compounds, are also well known in the art. Although the halogens provide wide germicidal activity, they have several undesirable properties. Halogen containing compositions are generally corrosive. Iodine containing compositions may also stain the surface being disinfected. Chlorine containing compositions are generally toxic.
[0007] Quaternary ammonium compounds are also well known in the art. However, the quaternary ammonium compounds have a limited germicidal range and have limited effectiveness in soaps, detergents and hard water salts.
[0008] Phenolic compounds are well known in the art. However, phenolic compounds have an unpleasant odor, and leave a sticky residue on surfaces.
[0009] Coal tar distillates, such as Cresol and Cresylic Acid, are well known in the art. However, coal tar distillates have several undesirable qualities as environmental surface disinfectants. Coal tar distillates are corrosive and toxic at high concentrations. In addition, coal tar distillates emit noxious gases.
[0010] Aldehydes, such as glutaraldehyde, are also well known in the art. However, aldehydes suffer the disadvantage of being moderately toxic.
[0011] Oxidizing agents, such as hydrogen peroxide and potassium permanganate, are also well known in the art. However, oxidizing agents have undesirable qualities. Oxidizing agents are corrosive and exposure to high concentrations (5% or greater) can result in eye and skin irritation.
[0012] There is thus a need in the art for an environmental surface disinfectant which may efficiently be employed for eliminating microorganisms, but which at the same time is non-toxic, has a mild odor, is compatible with cleaning compounds and does not react with solid substrates.
SUMMARY OF THE INVENTION
[0013] A composition and a method for disinfecting an environmental surface using that composition is provided. The surface is contacted with a biocidal effective amount of a composition comprising alkyl esters of lactic acid; and optionally, other common elements present in surface cleaners, such as water, surfactants, and odorants among others.
DETAILED DESCRIPTION OF THE INVENTION
[0014] Detailed descriptions of the preferred embodiments are provided herein. It is to be understood, however, that the present invention may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one skilled in the art to employ the present invention in virtually any appropriately detailed system, structure or manner.
[0015] The present invention involves using alkyl esters of lactic acid, which have heretofore been unappreciated for their surprising disinfectant properties, to disinfect environmental surfaces.
[0016] In accordance with the present invention, it has surprisingly been discovered that compositions based on alkyl lactate esters have remarkable antibacterial properties. The compositions of the invention comprise alkyl lactates wherein the alkyl group has 1 to 12 carbon atoms.
[0017] According to a first embodiment of the present invention, the environmental surface disinfectant contains a lactate as the antimicrobial ingredient. This lactate can be either methyl lactate, butyl lactate, or propyl lactate.
[0018] According to another embodiment of the present invention, the environmental surface disinfectant contains ethyl lactate as the antimicrobial ingredient. Ethyl lactate is non-toxic, and is used in foods and cosmetics. In addition, ethyl lactate has a mild odor and is not corrosive or reactive with most solid substrates.
[0019] Antimicrobial activity of the composition is attained at concentrations of ethyl lactate greater than two per cent, achieving maximal antibacterial activity at ethyl lactate concentrations of approximately fifty percent. Accordingly, the preferred concentration range for ethyl lactate when employed in the antimicrobial compositions is between two and fifty percent, although the range can be as high as one hundred percent. The composition of the invention may contain one or several other compounds with antiseptic properties, perfumes or other customary additives and auxiliaries such as surfactants. The compositions according to the invention can be prepared by mixing the individual components together successively, if necessary with heating. No particular order need be adhered to during this process.
EXAMPLE 1
[0020] The following example demonstrates that ethyl lactate is a potent bactericide. Using a modification of AOAC Method 956.17, the lower effective concentration for ethyl lactate was tested against E. coli (ATCC 25922) at three reaction times at varying concentrations of ethyl lactate. As the results in Table 1 show, exposure of E. coli to a 15% solution of ethyl lactate for 10 minutes eliminated bacterial growth.
TABLE 1 Lower effective concentration of ethyl lactate against E. coli (ATCC 25922) at final concentration of CA. 100 billion colonies for 24 hours. Ethyl lactate, Time Label concentration a 5 min. 10 min. 15 min. S-1 b 10% + c + + S-2 50% − d − − S-3 20% − − − S-4 30% − − − S-5 40% − − − S-6 15% + − − S-7 20% − − −
EXAMPLE 2
[0021] The following example shows one preferred embodiment according to the invention. A formulation is prepared as follows:
Ingredient Weight % Ethyl Lactate 16.0% Fragrance 1.0% Water 83.0%.
[0022] Fragrance is added first to the ethyl lactate and then mixed in the water.
[0023] Turning to Table 2, there is shown that the bactericidal efficiency of the formulation in Example 2 is comparable to that of 10% Clorox at the challenge times observed.
TABLE 2 Comparison of preferred embodiment with diluted Clorox against E. Coli (ATCC 25922) at concentration of CA. 100 billion colonies for 24 hours. Time Label concentration a 5 min. 10 min. 15 min. Clorox 10% N b N N Formulation 100% N N N
[0024] Turning to Table 3 there is shown with a conventional challenge test that the formulation eliminates E. Coli with a very high efficiency.
TABLE 3 Results of challenge test using E. Coli (ATCC 25922). Challenge volume: 5.0 ml Product volume: 0.5 ml E. Coli level of challenge liquid: 100 Billion CFU/ml* E. Coli level of treated liquid: <1 CFU/ml E. Coli removal efficiency: >99.999%
[0025] Tables 4 and 5 show with a conventional challenge test that the formulation eliminates the fungi Penicillum pinopillum and Aspergillus niger with a very high efficiency.
TABLE 4 Results of challenge test using Penicillum pinopillum . Challenge volume: 5.0 ml Product volume: 0.5 ml P. pinopillum level of challenge liquid: 0.4 Million CFU/ml* P. pinopillum level of treated liquid: 300 CFU/ml P. pinopillum removal efficiency: >99.25%
[0026] [0026] TABLE 5 Results of challenge test using Aspergillus niger . Challenge volume: 5.0 ml Product volume: 0.5 ml A. niger level of challenge liquid: 0.9 Billion CFU/ml* A. niger level of treated liquid: <1200 CFU/ml A. niger removal efficiency: >98.5%
[0027] It is thus apparent from the results of the Examples described above that the method of using alkyl lactates as environmental surface disinfectants according to the invention is a valuable method of disinfecting, possessing surprisingly good antimicrobial effects. The environmental surface disinfectant according to the present invention is particularly well-suited in medical and food preparation contexts also. The disinfectant according to the invention is moreover easy to produce by a simple mixing process.
[0028] One skilled in the art will appreciate that the particular alkyl lactate chosen can provide a more immediate and more effective reduction in microbial count depending on the microflora targeted. Accordingly, the described examples are merely exemplary and are in no way limiting.
[0029] The concentration of alkyl lactate in accordance with the present invention should be sufficient to effect the desired reduction in bacterial count over a reasonable time frame. One skilled in the art will recognize that concentration will depend upon a variety of factors, including the particular alkyl lactate employed, the targeted bacterial microflora, and the nature of the other compounds in the bacterial microflora may require prolonged treatment involving multiple applications of compositions of the present invention.
[0030] Suitable concentrations of alkyl lactate can be determined by conventional range-finding techniques known to those of ordinary skill in the art. Several standard methods for determining the antimicrobial efficacy of various concentrations of alkyl lactates as on the various resident and transient microflora of environmental surfaces are well known to those of ordinary skill in the art.
[0031] Seen as a whole, therefore, the compositions according to the invention are especially suitable as environmental surface disinfectants.
[0032] The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.
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An environmental surface disinfectant and its method of use are disclosed. The inventive environmental surface disinfectant comprises an effective concentration of an alkyl ester of lactic acid. Ethyl lactate is a preferred alkyl ester of lactic acid. Disinfection of an environmental surface is achieved by applying the disinfectant of the invention to the surface.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates generally to utility structures and, more specifically, to an Inflatable Shelter
[0003] 2. Description of Related Art
[0004] A myriad of temporary structures are available for a variety of specialty and general purposes. Many times these structures are lightweight tent-type structures that provide protection from the sun and weather as well as providing some measure of privacy. These structures are generally collapsible in order to make them easy to transport from location to location. The problem with tent structures is that their frames are many times fairly heavy and/or difficult to handle in cases where above-average durability or stability is required. Furthermore, the frame members are generally constructed from metal (again, for durability), which can corrode over time. None of these tent-type structures provides a lightweight, durable and easily-erected protective structure.
[0005] One specialty application area for temporary outdoor structures that has exploded in recent years is that of the play toy known as the “bounce house.” FIG. 1 is a perspective view of a conventional inflatable “bounce house.” The conventional bounce house is a completely collapsible structure that can be erected in minutes by a single person. As shown in the FIG. 1 example, the house 10 consists of two or more inflatable frame members 16 interconnected by wall skins 20 and a roof skin 18 . As is indicated by their name, the bounce house 10 has an inflatable floor pad 12 upon which children can bounce to their hearts' content without harm.
[0006] The houses 10 are generally transported to and from the locations of use in a tote bag (albeit a fairly large bag); upon arrival at the site, an electric (or gas-powered) blower 22 is first connected to the house 10 with an air fill tube 24 , and then turned on. Subject to the sizing of the blower 22 and house 10 , the typical inflation of the house 10 will take less than an hour. Furthermore, the transport, inflation and deflation of the house 10 can typically be accomplished by a single person. If we turn to FIG. 2, we can examine how the conventional bounce house is constructed.
[0007] [0007]FIG. 2 is a cutaway perspective view of the bounce house 10 of FIG. 1. As can be seen, the roof and wall skins 18 and 20 , respectively, are stretched between the inflated frame members 16 . The frame members 16 themselves are essentially long tubes made from rubber-impregnated canvas (much like an inflatable boat) and defined by a hollow frame chamber 32 into which air from the blower (see FIG. 1) is blown.
[0008] Similarly, the floor pad 12 consists of a floor chamber 30 enclosed between a floor pad bottom surface 28 (resting against the ground), and a floor pad top surface 26 (upon which the children bounce). The frame chambers 32 and floor chamber 30 are in fluid communication with one another such that when one is inflated (or deflated), the others are inflated or deflated as well. Because of the durability of the material used for the frame members 16 and floor pad 12 , the house 10 can be inflated to a fairly high pressure where exceptional structural integrity is necessary—this does not really add to the structural weight of the house 10 (at least when compared to the tent-type structures previously described).
[0009] Bounce houses 10 are constructed in a variety of shapes and sizes, including forms simulating animals, famous buildings, or even sinking cruise ships (the “Titanic”), with the intent being to provide the most entertainment for the children bouncing around inside of them. Common to all of these various shapes and sizes are the inflatable frame members 16 and inflatable floor pad 12 .
[0010] While the design for the bounce house 10 is interesting, it does not really provide the utility necessary for it to serve as a utility structure for temporary utilitarian use rather than as a child's play area. What is needed is an inflatable utility structure that provides the benefits of the bounce house 10 plus additional usefulness.
SUMMARY OF THE INVENTION
[0011] In light of the aforementioned problems associated with the prior devices, it is an object of the present invention to provide an Inflatable Shelter. The shelter should include a plurality of arched tubes designed to rest directly upon the ground or other surface. In order to provide cooling to occupants of the shelter, the shelter may include an attachable misting mesh for dispensing a fine mist of water or other fluid from the top of the shelter. It is a further object that the misting mesh may also be incorporated within the inflatable tubes of the shelter. It is another object that the shelter be attachable to an inflation air source as well as a liquid source for pressurizing the misting mesh. It is a still further object that the structure include tie-down loops extending from the feet of the arched tubes; these tubes being provided to accept stakes therethrough.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The objects and features of the present invention, which are believed to be novel, are set forth with particularity in the appended claims. The present invention, both as to its organization and manner of operation, together with further objects and advantages, may best be understood by reference to the following description, taken in connection with the accompanying drawings, of which:
[0013] [0013]FIG. 1 is a perspective view of a conventional inflatable “bounce house;”
[0014] [0014]FIG. 2 is a cutaway perspective view of the bounce house of FIG. 1;
[0015] [0015]FIG. 3 is a perspective view of a preferred embodiment of an inflatable shelter of the present invention;
[0016] [0016]FIG. 4 is a cutaway perspective view of a preferred embodiment of a rafter tube of the shelter of FIG. 3;
[0017] [0017]FIG. 5 is a cutaway perspective view of an alternate embodiment of a rafter tube of the shelter of FIG. 3;
[0018] [0018]FIG. 6 is a perspective view of a preferred misting mesh used with the shelter of FIG. 3;
[0019] [0019]FIG. 7 is a perspective view of an alternate embodiment of the shelter of the present invention; and
[0020] [0020]FIG. 8 is a perspective view of an assembly including an alternate embodiment of a water source for use with the shelters of FIG. 3 or 7 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0021] The following description is provided to enable any person skilled in the art to make and use the invention and sets forth the best modes contemplated by the inventor of carrying out his invention. Various modifications, however, will remain readily apparent to those skilled in the art, since the generic principles of the present invention have been defined herein specifically to provide an Inflatable Shelter.
[0022] The present invention can best be understood by initial consideration of FIG. 3. FIG. 3 is a perspective view of a preferred embodiment of an inflatable shelter 40 A of the present invention. Unlike the conventional bounce house described above, the shelter of the present invention eliminates the floor pad; this is for at least two reasons: (1) the floor pad provides unwanted cushioning, and (2) any floor covering (i.e. over the ground) in a utility environment will invariably become soiled, will wear out, and perhaps may be a safety hazard.
[0023] The structure 40 A comprises a plurality of hollow, inflatable arched tubes 42 interconnected by hollow rafter tubes 44 . The arched tubes 42 and rafter tubes 44 are in fluid communication with one another such that when one is inflated or deflated, all others are inflated or deflated as well. Of course, in larger or specialty designs, the tubes 42 and 44 may be grouped together so that they might be inflated separately (e.g. from separate blowers 22 ).
[0024] In this embodiment, the arched tubes 42 comprise a pair of vertical portions 46 A each terminating at the ground in feet 52 . At the opposite ends of the vertical portions 46 A are sloped portions 48 A; these then transition into a horizontal portion 50 (which interconnects the two sides).
[0025] As depicted, the vertical portions 46 A each terminate in a foot 52 at their ends. In close proximity to, or actually extending from each foot 52 are tie-down loops 54 or flaps for securing the shelter 40 A to the ground. The shelter 40 A is preferably secured to the ground with stakes 56 or the like pounded through one or more of the tie-down loops.
[0026] Similar to the bounce house discussed previously, the shelter 40 A is erected by inflating with a blower 22 forcing air through an air fill hose 24 . The hose 24 may be connected to any suitable connection point provided on any of the members of the shelter 40 A—here it is shown connected to the bottom of one of the vertical portions 46 A of the third arched tube 42 C.
[0027] In this embodiment, five arched tubes, 42 A- 42 D, respectively, are employed, however in other embodiments either more or fewer tubes 42 may be used, depending upon the desired length of the shelter 40 A.
[0028] In addition to those novel aspects previously discussed, one notable aspect of the shelter 40 A is that it can be configured to dispense a water mist downwardly in order to cool off persons that are under the shelter 40 A. The misting system obtains its water for misting from a water source 60 A, such as the outdoor hose bib shown. Water dispensed by the source 60 A is carried to the shelter 40 A by a water supply hose 62 , which then connects to the shelter at a water supply port 58 . Misting can be turned on or off either at the source 60 A or some other internal system valve. Examples of the entire misting system will be discussed below in connection with other drawing figures.
[0029] Also shown is a display panel 64 extending across the top section of the first arched tube 42 A. This panel 64 may be used to advertise or to otherwise display indicia thereon. The panel 64 is preferably made from the same flexible material as the tubes 42 and 44 .
[0030] Although not depicted here, it should be understood that the shelter may be configured with rollable or removable wall or roof panels for providing privacy, environmental protection, or even insect protection (such as by screens). One embodiment may comprise a permanently-attached solid vinyl sheet covering over the top portion of the shelter 40 A, and one or more vinyl sheets removably attached in between the vertical portions 46 , such as by hook-and-loop fasteners. Now turning to FIG. 4, we can examine the invention in more detail.
[0031] [0031]FIG. 4 is a cutaway perspective view of a preferred embodiment of a rafter tube 44 of the shelter of FIG. 3. In this embodiment, the rafter tube 44 includes an internal water distribution hose 70 A running through the rafter tube chamber 72 for distributing water from the supply system (see FIG. 3) and out to the individual misting nozzles 66 A. Under normal household pressure, the misting nozzles 66 A will provide a fine water mist 68 which serves to evaporatively cool the air in the general vicinity of the nozzles (i.e. inside the shelter). In this embodiments, the misting nozzles 66 A protrude through the tube wall 45 from the internal water distribution hose 70 A. If we turn to FIG. 5, we can review another embodiment of the nozzle arrangement.
[0032] [0032]FIG. 5 is a cutaway perspective view of an alternate embodiment of a rafter tube 44 of the shelter of FIG. 3. In this embodiment, there are one or more hose clips 74 attached to (or molded into) the outside of the tube wall 45 . The hose clips 74 are configured to securely grasp the external water distribution hose 70 B therein. The benefits of this externally-mounted version is that the rafter tube 44 air-tight integrity is not jeopardized by the through-penetration of the nozzles, and furthermore, there is greater flexibility and control by the user of the positioning of the misting nozzles 66 B—in fact, the nozzles 66 B might be re-positionable from location to location on the shelter. It should further be understood that while FIGS. 4 and 5 depict the nozzles 66 extending from the rafter tube 44 , they may also be positioned in other locations (e.g. from the arched tubes). Now turning to FIG. 6, we can examine how the individual misting nozzles are interrelated.
[0033] [0033]FIG. 6 is a perspective view of a preferred misting mesh 76 used with the shelter of FIG. 3. In this embodiment, the misting mesh 76 refers to a matrix of interconnected piping or tubes 78 that distribute water from the water supply port 58 and out to the individual misting nozzles 66 . As discussed above, the tubes 78 may be retained within the inflated structural tubes, or they may be attached to the outer surfaces of the structural tubes, or the may the positioned in a way that is a combination of the two. Furthermore, although not depicted here, a shutoff valve and/or pressure regulator may be included in the first branch tube 78 A; provided to control the water pressure and flow. The material used for the tubes 78 is extremely flexible and durable in order to permit the structure to be collapsed and packed into a single bag without damage to either the shelter or the mesh 76 . Similarly, the nozzles 66 are constructed in a way to prevent their cutting into any of the other portions of the shelter (i.e. from plastic with no sharp edges). Having completed the review of a first embodiment of the shelter of the present invention, we will now turn to FIG. 7.
[0034] [0034]FIG. 7 is a perspective view of an alternate embodiment of the shelter 40 B of the present invention. In this embodiment 40 B, alternate arched tubes 43 are employed. These alternate arched tubes 43 comprise vertical portions 46 B and long sloped portions 48 B, with the sloped portions 48 B meeting at the peak 80 of the shelter 40 B. This design provides more headroom than the previously-described embodiment, while retaining the benefits of light weight and ease of erection and packing. Although only three rows of rafter tubes 44 are shown here, it should be understood that additional rows may be added in alternate embodiments. Another optional element in this present invention is the second row of rafter tubes 47 ; these second rafter tubes 47 , if included, are essentially the same construction as those previously discussed (tubes 44 ).
[0035] Similar to the previous shelter embodiment, another embodiment of the instant shelter 40 B may comprise a permanently-attached solid vinyl sheet covering over the top portion (i.e. over the sloped portions 48 and peaks 80 ) of the shelter 40 A, and one or more vinyl sheets removably attached in between the vertical portions 46 , such as by hook-and-loop fasteners. Finally turning to FIG. 8, we can evaluate yet another alternate embodiment of a component of the present invention.
[0036] [0036]FIG. 8 is a perspective view of an assembly including an alternate embodiment of a water source 60 B for use with the shelters of FIG. 3 or 7 . In some remote locations, for example construction sites or remote holes on golf courses, there may not be a permanent water supply available; there may, however be electrical power available (e.g. from generators or inverters). In such cases, an alternate water source 60 B may be utilized. This alternate source includes a water pump 82 and a portable water reservoir 84 (although a lake or pond may be used, if it is clean enough). In this example, the water pump 82 and blower 22 are both being run from the same motor 88 . In other embodiments, the pump 82 and blower might be separate. Furthermore, it should be appreciated that the portable water reservoir 84 shown here is simply an theoretical example to demonstrate functional relations between the components; it is not intended to restrict the potential form of the reservoir 84 in any way.
[0037] Those skilled in the art will appreciate that various adaptations and modifications of the just-described preferred embodiment can be configured without departing from the scope and spirit, of the invention. Therefore, it is to be understood that, within the scope of the appended claims, the invention may be practiced other than as specifically described herein.
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An Inflatable Shelter is disclosed. The shelter includes a plurality of arched tubes designed to rest directly upon the ground or other surface. In order to provide cooling to occupants of the shelter, the shelter may include an attachable misting mesh for dispensing a fine mist of water or other fluid from the top of the shelter. The misting mesh may also be incorporated within the inflatable tubes of the shelter. Furthermore, the shelter may be attachable to an inflation air source as well as a liquid source for pressurizing the misting mesh. Still further, the structure may include tie-down loops extending from the feet of the arched tubes; these tubes being provided to accept stakes therethrough.
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GOVERNMENT RIGHTS
The invention described herein may be manufactured, used and licensed by the Government for Governmental purposes without the payment to us of any royalties thereon.
BACKGROUND OF THE INVENTION
Nitrocellulose, which is processed into various types of propellants and explosives, is manufactured from cellulose feed stocks consisting of fine fibers of cotton linters or macerated wood pulp.
In order to produce nitrocellulose, the cellulose feed stocks are treated with nitric acid to replace hydroxyl radicals in the cellulose structure with nitrate radicals. However, water is formed as a reaction product, and since the reaction is reversible, the water must be removed from the reaction site or the nitration reaction will not proceed to the desired degree. The nitration reaction can be written as follows:
Cellulose+Nitric acid⃡Nitrocellulose+Water
Water heretofore has been removed from the reaction site by introducing sulfuric acid together with the nitric acid reactant into the reaction mixture. The sulfuric acid takes up the water, thus permitting the nitration of the cellulose to proceed. This process requires a purification and stabilization step to remove all traces of sulfuric acid. This is necessary because any sulfuric acid remaining in the product acts to break down the nitrocellulose resulting in degradation of the product. Heat and fumes may be evolved and explosion or fire may ultimately occur. The resulting product would not be suitable for processing into propellants or explosives with long shelf lives and critical performance and physical characteristics.
The required purification and stabilization of the nitrocellulose formed in the nitric acid-sulfuric acid reaction involve long boiling and washing operations which consume large quantities of heat, water, steam and electricity, requiring a large and costly facility and stringent quality controls. Although the resulting product may be satisfactory, the process is long and costly and large quantities of contaminated water are produced, causing pollution problems.
Efforts have been made to develop a process which eliminates the need for using sulfuric acid, with little success. One approach has been to use high concentrations of nitric acid so the water produced by the reaction is taken up in diluting the concentrated acid. This is not satisfactory because the dilution of the acid occurring near the cellulose surface causes the acid concentration to reach a point where the nitrocellulose dissolves and precipitates in crystalline form, causing the surface to harden. This is known as gelatinization and it makes the nitrocellulose unsuitable for processing into propellants.
If the concentration of the nitric acid is kept below the level where gelatinization takes place, the water produced in the nitration reaction reduces the concentration to the point where the reaction becomes reversible and the nitration reaction cannot proceed to the desired degree.
The above demonstrates that there is a need for a process, either continuous or batch, which will accomplish the nitration of cellulose by reaction of nitric acid and cellulose without the presence of sulfuric acid and which will provide for the economical elimination of water to produce a nitrocellulose which is homogeneous and suitable for use in propellants.
BRIEF DESCRIPTION OF THE INVENTION
This invention relates to a process for the production of nitrocellulose from cellulose by nitration of the cellulose with nitric acid and, in lieu of sulfuric acid to remove water formed in the reaction, removing the water by introducing nitric oxide (NO 2 )gas and air or oxygen into the reaction mixture to form nitric acid. The nitric acid level is kept constant by adding the proper amount of NO 2 and oxygen(O 2 ). Any excess acid formed is either removed and collected or recirculated back into the reaction at a predetermined rate. The reaction can be carried out as a batch or continuous process.
In the batch process, the mixture of nitric oxide and air or oxygen is circulated directly into the nitration reactor to react with the water to form nitric acid. The excess nitric acid formed by the reaction of the NO 2 , O 2 and water can be circulated into a secondary reactor where acid regeneration takes place.
In a continous process, provision for continuous addition of the reactants at predetermined rates can be made. Any excess nitric acid regenerated can either be removed and collected or recirculated into a secondary reactor then back into the nitration reactor at a predetermined rate.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic representation of the apparatus and process of this invention; and
FIG. 2 is a schematic representation of the apparatus wherein a secondary reactor is used.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is based on the discovery that cellulose can be nitrated with nitric acid in either a batch or continuous process and a nitrocellulose product can be produced when nitric oxide(NO 2 ) and oxygen or air are introduced into the reactor to remove the water formed in the reaction by reacting therewith to form nitric acid. This prevents the water from diluting the nitric acid unduly which can dissolve and gelatinize the nitrocellulose product and also provides nitric acid for use in the process. In fact, the nitric acid level can be kept constant at a desired concentration by controlling the rate the NO 2 and air are introduced into the reactor.
The process of the invention thus eliminates the need for the use of sulfuric acid to take up the water. This is desirable because the sulfuric acid has undesirable effects on the product and process as discussed above.
The reactions involved in the process of this invention are as follows:
Reaction 1
C.sub.6 H.sub.10 O.sub.5 +3HNO.sub.3 →C.sub.6 H.sub.7 O.sub.2 (ONO.sub.2).sub.3 +3H.sub.2 O
and
Reaction 2
3H.sub.2 O+6NO.sub.2 +1.5O.sub.2 →6HNO.sub.3
The above two reactions are simplified as follows:
C.sub.6 H.sub.10 O.sub.5 +1.5O.sub.2 +6NO.sub.2 →C.sub.6 H.sub.7 O.sub.2 (ONO.sub.2).sub.3 +3HNO.sub.3
The cellulose can be in any convenient form to serve as a feedstock for the nitration reaction, such as for example, fine fibers of cotton linters or macerated wood pulp. The nitric acid used is commercial concentrated nitric acid, which may vary between about 80% and 100%, HNO 3 , depending upon the degree of nitration desired, as is well known in the art. Advantageously the mole ratio of nitric acid to cellulose varies from about 50:1 to about 60:1. This keeps the concentration of the acid in the reactor sufficiently high to avoid dissolving the nitrocellulose product. However, since in the process of this invention, the nitric acid concentration will not be diluted by the water formed in the reaction, somewhat lower concentrations can be used, e.g. about 30:1 to about 50:1.
The amount of nitric oxide used is proportional to the quantity of the cellulose being nitrated. Thus, for each mole of cellulose being nitrated, 6 moles of nitric oxide and 1.5 moles of oxygen are needed to react with the three moles of water formed. This regeneration process produces 6 moles of nitric acid. Since only three moles of nitric acid are consumed in the process of nitrating cellulose, the excess nitric acid can be separated and either collected or recirculated.
The reason oxygen or air is required is that Reaction 2 takes place in two steps and the oxygen is required in the second step as follows:
Reaction 3
H.sub.2 O+3NO.sub.2 →2HNO.sub.3 +NO
and
Reaction 4
NO+0.5O.sub.2 →NO.sub.2
The above two reactions are simplified as follows:
H.sub.2 O+2NO.sub.2 +0.5O.sub.2 →2HNO.sub.3
As shown in FIG. 1, cellulose is introduced through feed line 2 into the reaction vessel 1, 6 moles of concentrated nitric acid for each mole of cellulose are also introduced into the reaction vessel 1 through feed line 3. The reaction mixture at 0° C. to 40° C. is mixed by stirrer 6 and nitric oxide and air are mixed and circulated into the reaction vessel 1 through inlet 5. Excess nitric oxide and air are vented through line 4 and recirculated to inlet 5. The flow rate of the gas mixture varies according to the nitration velocity of the cellulose which velocity varies with temperature. A temperature range of 0° C. to 40° C. is satisfactory for both the nitration and nitric acid regeneration. The gas flow rate, taking into consideration the temperature and acid concentration, should be sufficient to enable the gas to react with all the water as it is formed.
Excess nitric acid formed is removed through line 7 and the nitrocellulose product is recovered through outlet 11.
In a continuous process, which is generally preferred, predetermined amounts of cellulose are continually fed through feed line 2 into the reactor 1; however, once the initial amount of nitric acid is added, no more than minor amounts for adjustment of acid concentration are subsequently added because sufficient nitric acid is formed by the addition of nitric oxide and oxygen.
An alternate process and apparatus is depicted in FIG. 2, wherein the same reagents are introduced into the reactor 1 and mixed as described above. The diluted nitric acid from the reactor 1 is directed to a secondary reactor 8 through line 10 and increased in strength by the action of NO 2 +O 2 (Reaction 2) introduced through the inlet 5. Excess NO 2 and O 2 are vented through the line 4 and are recycled to the inlet 5. The regenerated strong nitric acid is returned to the reactor 1 through the line 9 for nitrating more cellulose. The excess nitric acid formed is removed through the outlet 7 and the nitrocellulose product is recovered through the outlet 11. Nitric acid inlet 3 is kept closed most of the time except at the beginning.
The reactions shown can be carried out either in a batch or continuous process. The continuous process is preferred since it is more convenient and economical.
This invention has been described with respect to certain preferred embodiments and modifications. Variations in the light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application and the scope of the appended claims.
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There is disclosed a process for the nitration of cellulose with nitric acid in the absence of sulfuric acid which comprises adding sufficient nitric oxide and oxygen or air to the nitration reaction mixture to react with the water formed in the reaction. This regenerates nitric acid which can be recycled to the reaction or removed and collected.
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BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates generally to an apparatus for inserting metal stampings into a mold prior to subsequent operations and, more particularly, to an automated apparatus for accurately inserting precision miniature stampings into a mold cavity prior to a subsequent molding operation.
DESCRIPTION OF THE BACKGROUND
There are numerous instances in which metal parts are inserted into a mold cavity prior to subsequently molding those parts into a plastic or resin body using the mold cavity. Typically, in the case of precision stampings forming contacts in a miniature switch, sensor connector or any miniature metal/plastic assembly, the stampings are frequently inserted by hand into the mold cavity as it is arranged on a conveyor belt or rotary work table or the like. Such hand placement is required due to the extremely small size of the stampings being inserted into the mold cavity and also due to the requirement for highly accurate placement of these stampings in the mold cavity.
On the other hand, the manual placement of the contacts, while providing accuracy, is slower than desired in view of modern automation techniques and the requirement to produce large quantities at competitive pricing of the resultant end products.
Generally, in prior attempts to automate this process by either bowl feeding techniques or robotics it was found that in the first instance the parts were typically too small or too fragile to be accurately dealt with or it was not accurate enough concerning the required location for the stampings in the mold cavity and, in the second instance, such attempts were not sufficient in speed to meet the output requirements.
OBJECTS AND SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide an apparatus for automatically inserting precision metal stampings into a mold cavity that can eliminate the above-noted problems inherent in the previously proposed systems.
Another object of this invention is to provide an apparatus for inserting precision metal stampings into a mold cavity that can perform at a speed faster than the combined cycle of the time of molding and the mechanism delivering the mold cavities to the automatic insertion location.
A further object of this invention is to provide an automated apparatus for inserting stampings into a mold cavity wherein the stampings are originally in the form of a pre-formed strip that is automatically fed into the apparatus and whereby the stampings are automatically severed from the strip and inserted into the mold cavity at the correct locations.
In accordance with an aspect of the present invention, a stamping insertion head is provided that operates both electrically and pneumatically in conjunction with a pre-formed strip bearing stampings so that the stampings are automatically severed from the strip and inserted into a mold cavity which resides on either a rotary table or a shuttle-type table prior to an operation of molding a plastic switch, sensor, or connector using the mold cavity. The insertion head is mounted on a so-called X-Y-Z coordinate table that has three degrees of freedom so that it may move both horizontally and vertically relative to the mold cavity, as well as forward and backward relative to the mold cavity, a number of which are arranged on a rotary table, for example. Steel pins are provided to accurately locate the insertion head relative to each successive mold cavity, as each mold cavity moves into place for the stamping insertion operation.
The above and other objects, features, and advantages of the present invention will become apparent from the following detailed description of illustrative embodiments thereof to be read in conjunction with the accompanying drawings, in which like reference numerals represent the same or similar elements.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an overall perspective view of the insertion head apparatus used in conjunction with a number of mold cavities arranged on a rotary table, according to an embodiment of the present invention;
FIG. 2 is a side elevational view of a portion of the apparatus shown in FIG. 1;
FIG. 3 is a front elevational view of a portion of the apparatus shown in FIG. 1;
FIG. 4 is a top, plan view of a portion of the apparatus of FIG. 1;
FIG. 5 is a side elevational view in partial cross-section taken through section lines 5--5 in FIG. 4;
FIG. 6 is a front elevation view in partial cross-section taken through section lines 6--6 in FIG. 4;
FIG. 7 is an example of a pre-formed strip for use in the embodiment shown in FIG. 1; and
FIG. 8 is an electrical/pneumatic schematic for operating the actuating and adjusting elements used in the embodiment of FIG. 1.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
FIG. 1 shows the inventive insertion head apparatus generally at 10 in relation to a number of mold cavity bases, shown typically at 12. The mold bases 12 are arranged on and bolted to a so-called rotary table 14, which rotates in the direction of arrow 15. Each mold base 12 can typically have four cavities (not shown) and it is into these cavities that the stampings are inserted by the insertion head apparatus 10 prior to a plastic molding operation. In that regard, the rotary table 12 is caused to rotate in the direction shown by the arrow 15, so that the mold base 12 that has had the stampings inserted therein will ultimately be arranged adjacent to the plastic molding head, not shown in FIG. 1, for the resultant molding operation in order to fabricate the switch, sensor, or electrical connector that forms the desired end product.
In the insertion head apparatus 10, a ball slide assembly 16 is provided that can move vertically in the directions shown by arrow 17 under power from an air cylinder 18. The ball slide assembly 16 includes die head assembly 19 that can move laterally, or side to side, in the directions shown by arrow 20 under power from a stepper motor 21 that turns a lead screw 22, all of which will be shown in more detail in the other drawings.
The die head assembly 19 can also move in front to back directions relative to the mold base 12, as represented by arrow 23. This is accomplished by mounting the die head assembly on a pair of shafts 24 that respectively cooperate with a pair of pillow blocks 25. The die head assembly 19 is moved along the shafts 24 by means of a stepper motor 26 and a lead screw or ball screw 27. In this way the die head assembly 19 moves radially relative to the rotary table 14. The stampings that are to be inserted into the mold bases 12 are pre-formed as part of a strip 30 that is drawn through the die head assembly 19 by feed rollers, not shown in FIG. 1, which are driven by a stepper motor 32.
As described above, an object of this invention is to accurately insert the miniature precision stampings into the mold base and this accuracy is ensured according to the embodiment of FIG. 1 by using two steel pilot pins, one of which is shown at 34 in FIG. 1. The steel pilot pins 34 are machined to close tolerances and are firmly affixed to a pilot pin carriage 36. The two pins 34 are mounted on the pilot pin carriage 36, which is moved downwardly so that the pins 34 are inserted into respective pilot holes, shown typically at 38 bored into each of the mold bases 12.
The operations of cutting the stamping from the pre-formed strip 30 and subsequently inserting the stampings into the mold base 12 are performed by punches and slides and the like that will be described in detail hereinbelow. More specifically, a cutoff slide is driven by an air cylinder 40 and a pilot pin holder used to locate the strip 30 is driven by an air cylinder 42. An air cylinder 44 drives a first punch and a second punch is driven by an air cylinder 46, all of which are mounted on the die head assembly 19.
FIG. 2 is a side elevational view of the embodiment of FIG. 1 in which, in addition to the air cylinder 18 that drives the ball slide assembly 16 vertically, a further air cylinder 50 is provided that drives the pilot pin carriage 36 so that the pilot pins 34 can be inserted into the holes 38 formed in the mold base 12, thereby accurately locating the die head assembly 19 relative to the mold base 12.
In that regard, in order to permit some movement of the insertion head apparatus 10 to obtain proper alignment with each mold base 12, the insertion head apparatus 10 is mounted on a so-called ball bearing plate 52, the details of which will be shown in FIG. 5. The ball bearing plate 52 is part of the overall base structure assembly 54 of the insertion head apparatus 10, and the base structure assembly 54 also includes an upright plate 56 and an angled support plate 58.
As shown in FIG. 3, the stepper motor 32 is connected to drive a belt 60 that is connected to a lower strip feed roller 62. An upper strip feed roller 64 is connected as an idler roller relative to the driven lower feed roller 62, with the strip, not shown in FIG. 3, being stepped accordingly as the stepper motor 32 is driven in accordance with the system shown in FIG. 8. A roller lifter 66 in the form of a bar-type handle is provided to manually raise the upper feed roller 64, so as to remove the strip from the die head assembly 22. The roller lifter 66 is also used to open the feed roller assembly when starting or inserting the strip, not shown in FIG. 3.
The air cylinders 40, 42, 44, and 46 are used in conjunction with the strip 30 having the stampings pre-formed therein. More specifically, air cylinder 46 drives a cut-off punch 70 and air cylinder 44 drives another cut-off punch 72. On the other hand, air cylinder 42 drives a pilot pin holder 74 that serves to accurately locate the pre-formed strip 30 relative to the die head assembly 19, so that the appropriate punching operations can remove the stampings from the strip 30. In that regard, air cylinder 40 drives a cutoff slide 76 shown in FIGS. 2 and 4 that is used as a die cutting edge for the cutting off of the part from the step 30 as shown in FIG. 7. The air cylinder 40 is timed in its operation to retract cutoff slide 76 to the out position before the strip is fed.
FIG. 4 is a top view of the insertion head apparatus 10 in which the cutoff slide 76 is shown for actuation by the air cylinder 40, and the drive belt 60 is shown driven by the stepper motor 32. In addition, in FIG. 4 the four special ball bearing mounting assemblies, shown typically at 80, are used to mount the ball bearing plate 52 to the overall base plate 82 of the apparatus.
FIG. 5 is an elevational view in partial cross-section taken along section lines 5--5 in FIG. 4 in which the various elements making up the insertion head apparatus 10 are shown in more detail.
Referring then to FIG. 5, which is a side elevational view in partial cross section, the cut-off slide 76 is shown more clearly relative to the die head assembly 19. In addition, the interaction between the steel pilot pin 34 and the pilot pin alignment hole 38 in the mold base 12 is shown more clearly in FIG. 5. The so-called ball bearing plate 52 is attached to the overall base plate 82 of the unit by the ball bearing mounting assemblies 80, which each include a bolt 84 that sandwiches the ball bearing plate 52 between two ball bearing units 86 and 88. These ball bearing units permit some degree of movement for the ball bearing plate 52, thereby permitting the insertion head apparatus 10 to be aligned with the mold base 12 when the two alignment pins 34 are presented to the respective alignment holes 38. There are four separate ball bearing mounting assemblies 80, each consisting of bolt 84 and the two ball bearing units 86 and 88 at each corner of the ball bearing plate 52, as shown in FIG. 4, for example.
The ball bearing plate 52 has four bolts 84 mounting it to the base plate 82, and the through holes 90 that are bored through the ball bearing plate 52 are considerably larger in diameter than the shank of the bolts 84. Thus, these clearance holes 90 permit a rotational movement of the ball bearing plate 52 if such is necessary to align the head assembly 19 with the mold base 12.
The ball slide assembly 16 can move in the vertical direction and the die head assembly 19 can move horizontally relative to the ball slide assembly. In regard to vertical movement of the ball slide assembly 16, the air cylinder 18 causes the ball slide assembly to move along two main shafts 94 in the vertical direction. The ball slide assembly 16 is mounted on the main shafts 94 by linear bearings 96.
On the other hand, the die head assembly 19 can move in the horizontal direction by sliding along two horizontally arranged rails 98 and 100 under control of the stepper motor 21 that rotates the lead screw 22 which is threaded into a nut 102 affixed to the die head assembly 19.
In order to align the die head assembly 19 with a particularly located cavity in the mold base 12, the die head assembly 19 can move forwards and backwards by action of the stepper motor 26 and lead screw 27 moving the die head assembly 19 with the pillow blocks 25 along the horizontal shafts 24.
Similarly, the pilot pin carriage 36 also moves along main shafts 94 under control of the air cylinder 50. The pilot pin carriage 36 is mounted on the main vertical shafts 94 by linear bearings 104. As shown in FIG. 5, the pilot pin carriage 36 has not yet been moved downwardly under control of air cylinder 50, so that pilot pins 34 are not yet engaged with the holes 38 of the mold base 12.
FIG. 6 is a closer and more detailed view of the arrangement of the operating elements in the die head assembly 19. More specifically, the air cylinders 42, 44, and 46 are used to operate the various punches and the like, and the cutoff punch 70 is driven by air cylinder 46 to cutoff and insert a precision stamping formed on the strip 30. Similarly, cutoff punch 72 is driven by air cylinder 44 also to cut off another stamping located along the pre-formed strip 30. The pilot pin holder 74 is driven by air cylinder 42 and is used to accurately locate the strip 30 as it is fed through the insertion head. In that regard, as shown in FIG. 6, the pre-formed strip 30 is not yet in contact with the two rubber drive rollers 62 and 64. It is be understood that the strip 30 is inserted and caused to be engaged by the idler roller 64 and the drive roller 62, which is driven by the stepper motor 32. Thus, prior to the cut off and insertion operations performed by cutoff punches 70, 72 and cutoff slide 76, the pilot pin holder 74 is first actuated by air cylinder 42, so that the strip 30 is properly located in the die head assembly 19.
The upper feed roller 64 and the lower feed roller 62 cooperate to progress the strip 30 through the head at precise lengths. The upper feed roller 64 is spring loaded downwardly toward the lower feed roller 62 and applies a constant force against the strip 30 that is trapped between the upper roller 64 and the lower roller 62. The lower feed roller 62 is rotationally driven a precise amount by the stepper motor 32 that is accurately controlled by a logic controller as shown in detail in FIG. 8.
FIG. 7 is a view of the pre-formed strip 30 showing six separate groups of two stamping configurations. The pre-formed strip 30 is a generally flat metal strip 110 that has a plurality of holes formed therein shown typically at 112. These holes are sequentially contacted by the pilot pin holder 74 to accurately locate the strip 110 relative to the die head assembly 19. Each group of stampings is identical and in this embodiment there are two stamping configurations. One such stamping is shown typically at 114 and another at 116. It is understood, of course, that the exact nature of the stampings is not important but, rather, it is the manner in which such stampings are driven or pressed into the mold cavity by the respective punches, such as 70 and 72 in FIG. 6.
FIG. 8 represents an electrical and pneumatic schematic of the system shown in FIG. 1 in which a programmable logic controller 120, which may comprise a microcomputer or the like, is used to control the overall operations of the mechanical and electrical elements in the system. More particularly, a plurality of compressed air valves and a manifold 122 is connected by a respective plurality of signal lines 124 to the programmable logic controller 120. A source of compressed air 126 provides the appropriate compressed air over pneumatic line 128 to the manifold and valves 122, with such valves being then under control of the programmable logic controller 120. More specifically, the compressed air cylinder 42 is connected by a pneumatic line 130 to control the pilot pin holder 74. The pneumatic cylinder 44 is connected by pneumatic line 132 to control the cutoff punch 72 and the air cylinder 46 is controlled by pneumatic line 134 to control the cutoff punch 70. The horizontal cutoff slide 76 is driven by air cylinder 40 that connected by pneumatic line 136 to valves 122. The ball slide assembly 16 is driven by air cylinder 18 that is controlled by pneumatic line 138, and the pilot pin table 36 is controlled by air cylinder 50 under control of pneumatic line 140.
The three stepper motors are also controlled by the programmable logic controller 120 and, specifically, the horizontal ball slide assembly stepper motor 21 that drives the lead screw 22 is electrically controlled by a signal on line 142 and the strip stepper motor 32 that drives the lower roller 62 for the preformed stamping strip 30 is controlled by line 144. The stepper motor 26 that moves the die head assembly 19 along shafts 24 using lead screw 27 is electrically controlled by a signal on line 146 from the logic controller 120. It is, of course, understood that the motors are connected to the appropriate power sources through conventional wires, not shown.
In addition, because the programmable logic controller 120 must control the various air cylinders and stepper motors in synchronism with the rotation of the rotary table 14, signal lines 148 are provided for communication between the programmable logic controller 120 and the rotary table 14.
Although the present invention has been described hereinabove with reference to the preferred embodiments, it is to be understood that the invention is not limited to such illustrative embodiments alone, and various modifications may be contrived without departing from the spirit or essential characteristics thereof, which are to be determined solely from the appended claims.
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An apparatus for inserting preformed miniature precision metal stampings into a mold cavity for a subsequent plastic molding operation includes close tolerance positioning pins that accurately locate a die head assembly by fitting into respective holes in the mold base and pneumatic and electric motors for moving the die head vertically and horizontally, as well as forward and backward relative to the mold base. The metal stampings are preformed on a metal strip that is indexed in the insertion head by a pneumatically driven pilot pin and then pneumatic cylinders operate cutoff punches that detach the stampings from the strips and place them in the mold cavity. The entire insertion head assembly is permitted a small amount of movement necessary to align the positioning pins in the mold base holes by the provision of ball bearing mounting assemblies used to attach the insertion head apparatus to the base plate of the machine.
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TECHNICAL FIELD
[0001] The present invention generally relates to wireless communication networks, and particularly relates to base-station interface enhancements in multi-operator networks, such as where two or more operators share the same Radio Access Network (RAN).
BACKGROUND
[0002] The Third Generation Partnership Project (3GPP) Technical Specification (TS) 36.423 details the “X2” interface, used between radio base stations in Evolved Terrestrial Radio Access Networks (EUTRAN). A base station in the EUTRAN context is termed an “eNB” or “eNodeB.” Among other uses, the X2 interface provides for the distribution of own-cell configuration data to neighboring eNBs.
[0003] For each cell, the cell's own “served” Public Land Mobile Networks or PLMNs are signaled to the neighboring cells. In other words, a given radio cell may provide access to more than one PLMN, and each such PLMN may be associated with a different network operator. Often, within the multi-operator scenario, a given RAN cell supports two or more core networks, where each network is associated with a different operator.
[0004] However, even where a given cell is associated with multiple core networks, at any given time not all such networks may be available for serving user equipment (UE). As one example, communication with the Mobility Management Entity (MME) or other element in an associated core network may be lost, at least temporarily. Or, some functionality within a given core network may be temporarily impaired. In such cases, the PLMN associated with that network is considered unavailable for serving UEs (e.g., mobile terminals and other communication devices).
[0005] When a served PLMN is lost at a given cell, the PLMN is removed from the system information broadcast (SIB) transmitted by the cell, to prevent UEs associated with that PLMN from attempting to camp in the cell. The loss is also indicated to neighboring cells over the X2 interface, such as by removing the IDs of unavailable PLMNs from the cell information update messages that are sent between eNBs. Making the loss visible to neighboring cells prevents, for example, those neighboring cells from attempting (prepared or blind) handover of UEs into the cell, for PLMNs that are unavailable in the cell.
[0006] As a general proposition, each cell maintains some form of neighbor list information, such as one or more tables or other data structures, including entries for each neighboring cell, its ID, and the IDs of the served PLMNs that are available in the neighboring cell. The cell also maintains certain performance data, such as handover performance data that indicates in one sense or another handover performance from or to the neighboring cell. Additionally, or alternatively, the same or other performance data may be maintained in an operations and maintenance node, which may store a listing of associated cells and, for each such cell, neighboring cell data. When the last served PLMN available in a given cell is lost, that cell is removed from neighbor cell listings in the surrounding cells, as it no longer offers any served PLMNs for use by UEs. Commonly, when a cell is removed from the neighbor list in a given base station, that base station also removes performance or other data that is specific to the removed cell. Further, such cell data deletions may be propagated to operations and maintenance (O&M) entities.
SUMMARY
[0007] In one aspect, the teachings herein provide an enhanced inter-base-station interface and associated processing in which a base station receives a message from a neighboring base station that zero served PLMNs are available in a neighboring cell. In response to receiving that message, the base station removes the neighboring cell from its neighbor list, or otherwise marks the neighboring cell as unavailable, but advantageously does not discard any network performance data accumulated or otherwise generated for that neighboring cell. Correspondingly, should the base station receive a subsequent message indicating that one or more served PLMNs have become available in the neighboring cell, it restores the neighboring cell to its neighbor list and reinstates links or associations, as needed, to the retained network performance data.
[0008] Thus, in one embodiment the present invention comprises a method of maintaining external cell information for a first cell with respect to one or more neighboring cells. The method includes maintaining network performance data for the neighboring cells reflecting historic or expected handover performance for the neighboring cells with respect to the first cell. In more detail, the method includes maintaining a cell list of those neighboring cells that are available for handover based on receiving a cell information message from each such neighboring cell that indicates the neighboring cell has at least one served PLMN available. The method further includes removing a given neighboring cell from the cell list, or otherwise marking it as unavailable, in response to receiving a cell information message from the given neighboring cell that indicates that no served PLMNs currently are available in the neighboring cell, while retaining the network performance data for the given neighboring cell. The performance data is retained for use in the case that one or more served PLMNs once again become available in the given neighboring cell.
[0009] The above method is implemented in a wireless communication network node, for example. In one embodiment, the node includes one or more processing circuits that are configured, e.g., programmatically configured, to carry out the method. The wireless communication network node comprises an eNodeB in an LTE example, wherein neighboring eNodeBs exchange messages over their X2 interfaces, indicating the availability (or lack thereof) of served PLMNs in their corresponding cells.
[0010] In another embodiment, the present invention comprises a method of indicating the loss of served Public Land Mobile Network (PLMN) availability for a given cell in a wireless communication network. The method includes detecting that no served PLMNs are available for use in providing service in the given cell, and correspondingly setting an indicator value to zero, or another value logically deemed to be zero, in response to detecting that no served PLMNs currently are available for providing service in the given cell. Further, the method includes sending a cell information message to a neighboring cell, where the cell information message conveys the indicator value, to inform the neighboring cell that the given cell currently has no served PLMNs available. In an LTE example, one eNodeB would form such a message, e.g., in response to detecting the loss of the last available served PLMN in its cell, and send a cell information update message over its X2 interface with a neighboring eNodeB. That message would include a served PLMN indicator (e.g., a count value), indicating that zero served PLMNs are available in the cell, thus allowing the neighboring eNodeB to remove the cell at least temporarily from its neighbor list as a handover target, etc.
[0011] The method immediately above is implemented, for example, in a wireless communication node configured for use in a wireless communication network. The node is configured to indicate the loss of served PLMN availability for a given cell in the wireless communication network, based on including one or more processing circuits that are configured to detect that no served PLMNs are available for use in providing service in the given cell, and set an indicator value to zero, or another value logically deemed to be zero, in response to detecting that no served PLMNs currently are available for providing service in the given cell. Further, the node is configured to send a cell information message to a neighboring cell, said cell information message conveying said indicator value, to inform the neighboring cell that the given cell currently has no served PLMNs available.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a block diagram of one embodiment of a wireless communication network, which includes base stations configured according to one or more embodiments of the present invention.
[0013] FIGS. 2-6 are example diagrams of external cell information lists, such as may be maintained at base stations and/or operations and maintenance nodes, according to one or more embodiments of the present invention.
[0014] FIG. 7 is a block diagram of a base station and its associated interface and processing circuits, as configured according to an example embodiment of the present invention.
[0015] FIG. 8 is a logic flow diagram of a method according to one embodiment of the present invention, such as may be implemented by the base station of FIG. 7 .
[0016] FIG. 9 is a logic flow diagram of a method according to another embodiment of the present invention, such as may be implemented by the base station of FIG. 7 .
DETAILED DESCRIPTION
[0017] FIG. 1 is a block diagram of one embodiment of a wireless communication network 10 , including neighboring base stations 12 , denoted as “BS 1 ” and “BS 2 . ” Each base station 12 has an associated cell 14 , denoted as “Cell 1 ” for BS 1 , and as “Cell 2 ” for “BS 2 .” In this context, each base station 12 includes memory 16 (which may be one or more types of computer memory and/or disc storage), for storing an external cell list and associated performance data 18 , which is referred to as “data 18 ,” or “list 18 ” for ease of discussion. The data 18 includes neighbor cell information, such as a listing by cell ID, of all neighboring cells, along with further data, such as IDs of the served PLMNs that are available in each neighboring cell 14 , and “performance” data, such as historic or accumulated data regarding call handover performance to or from each neighboring cell 14 .
[0018] Each base station 12 constitutes a portion of one or more Radio Access Networks (RANs), and it will be understood in the art that multiple network operators (service providers) can share one or more of the base stations 12 . By way of example, BS 1 is shown as communicatively coupled to two Core Networks (CNs) 20 . One CN 20 is denoted as “PLMN A” and the other one is denoted as “PLMN B.” (While BS 2 is also shown communicatively coupled to the same PLMNs A and B, it is not necessary for all neighboring cells 14 to share all PLMNs in common.)
[0019] For further example details, one sees that the CN 20 of PLMN A includes a Mobility Management Entity (MME) 22 , and a Serving Gateway (S-GW) node 24 . The other CNs 20 generally include similar equipment, along with potentially many other types of nodes or entities, although such details are not needed for understanding the present invention and are therefore not illustrated. Each BS 12 also may be connected to a respective Operations & Maintenance (O&M) node 26 .
[0020] It may be that the number of served PLMNs available in Cell 1 or Cell 2 changes, at least on a temporary basis, because of communication link or equipment failures, or because of other dynamic conditions. FIG. 1 attempts to illustrate this case with the circled numerals “ 1 ” and “ 2 ,” which are shown adjacent to the links between BS 1 and PLMN B and PLMN A, respectively. At some time, “T 1 ” denoted by the circled 1 , PLMN B becomes unavailable for serving UEs 30 in Cell 1 . ( FIG. 1 depicts one UE 30 as an example, where UE 30 is shown moving toward or from an overlapping boundary region of Cells 1 and 2 —i.e., where inter-cell handover generally would occur.) At some later time, “T 2 ” as denoted by the circled 2 , PLMN A also becomes unavailable for serving UEs 30 in Cell 1 . At that point, at least temporarily, no served PLMNs are available in Cell 1 and Cell 1 is therefore unavailable for use by Cell 2 as handover target.
[0021] FIG. 2 depicts an example of the list 18 as maintained in BS 1 with respect to neighboring Cell 2 . One sees a table-like data structure, showing an entry for Cell 2 (by cell ID or other #), and associated data indicating the served PLMNs available in Cell 2 (here PLMN A and PLMN B). The list 18 also includes network performance data, preferably for each neighboring cell 14 . For each such neighboring cell 14 , the network performance data comprises, for example, one or more data items or metrics reflecting historic handover performance, e.g., metrics indicating handover reliability, handover triggering thresholds, etc., associated with Cell 2 , taken with respect to Cell 1 .
[0022] Correspondingly, in FIGS. 3-5 , one sees a similar list 18 , as maintained in BS 2 for Cell 2 with respect to Cell 1 . In particular, FIG. 3 depicts the list 18 in BS 2 at a time before T 1 . Thus, one sees that both PLMN A and B are indicated as being available in the list entry corresponding to Cell 1 . In FIG. 4 , one sees the list 18 as updated in BS 2 after time T 1 . For example, Cell 1 loses its communication link with PLMN B at time T 1 , and in response BS 1 sends a cell information update message to BS 2 , indicating that PLMN B is not available. Accordingly, BS 2 strikes PLMN B from its list 18 (either deletes it outright, or marks it as unavailable, as regards Cell 1 ). However, BS 2 advantageously retains the performance data for both PLMN A and PLMN B, relating Cell 2 to Cell 1 , in case the loss of PLMN B is temporary. That is, rather than delete all information from its list 18 for PLMN B, for Cell 1 upon receiving an indication that PLMN B is unavailable in Cell 1 , BS 2 advantageously retains such data, in case service via PLMN B is restored within Cell 1 . Of course, an O&M node 26 of other entity may communicate with BS 2 , and provide for permanent removal of such performance data, in cases where it is desirable to permanently delete such data.
[0023] Continuing, FIG. 5 depicts the same list 18 in BS 2 , but updated after time T 2 , where connectivity to PLMN A in Cell 1 has been lost. Now, as is indicated by the strikethroughs in the PLMN entries for Cell 1 in the list 18 , BS 2 has deleted both PLMN A and PLMN B from its listing of served PLMNs available for use in Cell 1 (or has otherwise marked them as unavailable), but has retained network performance data for both such PLMNs, with respect to Cell 1 . Again, if PLMN A or B, or both, become available in Cell 1 again, then BS 2 can begin using such performance data again, e.g., in making handover decisions with respect to Cell 1 , for PLMN A or B.
[0024] Further, one sees in FIG. 6 that such data retention methods also can be advantageously used in one or more O&A nodes 26 . That is, an O&A node 26 may retain neighbor list information 32 for each cell 14 that is associated the O&A node 26 . That is, the O&M node 26 is associated with a number of cells 14 , and each such cell 14 has associated with it a list 18 of neighbor cell information and corresponding performance data. Thus, the O&M node 26 may further retain performance data for each such cell that appears in one or more of those neighbor lists, even where no served PLMNs are currently available in such a cell, so that such data is still available if service with at least one PLMN is restored for that cell. Of course, the O&M node 26 is configured in one or more embodiments to provide for permanent removal of performance data relating particular cells, in cases where permanent deletion is desired.
[0025] Turning back to base station details, FIG. 7 depicts an example base station 12 , which may be BS 1 and/or BS 2 . (In one embodiment, the base station 12 is an eNodeB for use in an LTE network.). With the illustrated base station 12 , one sees an inter-base station interface 40 , a CN interface 42 , and an air interface 44 included within the illustrated base station 12 . Further, the base station 12 includes one or more processing circuits 50 , that (at least functionally) include a signaling controller 52 , a handover controller 54 , and an external cell information manager 56 , along with the memory 16 /list 18 first illustrated in FIG. 1 . In an LTE embodiment, the inter-base station interface 40 comprises an X2 interface and, in general, the inter-base-station interface 40 comprises circuitry that implements the physical layer signaling, along with the logical processing associated with protocol implementation, message processing, etc., for communicating with neighboring base stations 12 Similarly, the CN interface 42 comprises circuitry that implements the physical layer signaling, along with the logical processing associated with protocol implementation, message processing, etc., for communicating with one or more core network entities.
[0026] Further, the air interface 44 comprises circuitry that implements the physical layer signaling, along with the logical processing associated with protocol implementation, message processing, etc., for communicating with UEs 30 . In particular, those skilled in the art will recognize that the air interface 44 includes RF transceiver circuitry, for wirelessly transmitting to and receiving from a plurality of UEs 30 .
[0027] Continuing, the signaling controller 52 manages communications (protocol processing, etc.) for one or more of the communication interfaces, e.g., the inter-base-station interface 40 . For example, the signaling controller 52 may communicate with the external cell information manager 56 , responsive to inter-base station signaling, with the external cell information manager 56 updating its list 18 in memory 16 , responsive to such communications. In turn, that information, e.g., the performance data included in the list 18 , may be used by the handover controller 54 , for directing or otherwise controlling handover of UEs 30 to or from the cell(s) associated with the base station 12 .
[0028] More broadly, the illustrated base station 12 can be understood as an example illustration of a wireless communication network node as taught in one embodiment herein. Such a node is configured to maintain external cell information for a first cell 14 with respect to one or more neighboring cells 14 , and to maintain network performance data for the neighboring cells 14 reflecting historic or expected handover performance for the neighboring cells 14 with respect to the first cell 14 . The node includes one or more processing circuits (e.g., processing circuit(s) 50 ) that are configured to maintain a cell list 18 of those neighboring cells 14 that are available for handover based on receiving a cell information message from each such neighboring cell 14 that indicates the neighboring cell has at least one served PLMN available. The processing circuits are also configured to remove a given neighboring cell 14 from the cell list 18 , or otherwise mark it as unavailable, in response to receiving a cell information message from the given neighboring cell 14 that indicates that no served PLMNs currently are available in the neighboring cell 14 , while retaining the network performance data for the given neighboring cell 14 , for use in the case that one or more served PLMNs once again become available in the given neighboring cell 14 .
[0029] In one such embodiment, the one or more processing circuits are configured to detect that no served PLMNs are available in the given neighboring cell 14 , based on processing one or more information elements included in the cell information message.
[0030] In the same or another embodiment, the node comprises a first eNodeB for use in an LTE network, where the first and one or more neighboring cells are cells in the LTE network. In this embodiment, the node is configured to detect that no served PLMNs are available in the given neighboring cell 14 , based on receiving a cell data update message over an X2 interface between the first eNodeB and a second eNodeB (which is associated with the given neighboring cell), and detecting that the number of Broadcast PLMNs indicated in the cell data update message is zero. In at least one such embodiment, the first eNodeB is configured to detect that one or more served PLMNs have become available again in the given neighboring cell 14 , based on receiving a later cell data update message over the X2 interface, and detecting that the number of broadcast PLMNs indicated in the later cell data update message is greater than zero.
[0031] FIG. 8 illustrates a corresponding example method of maintaining external cell information for a first cell 14 with respect to one or more neighboring cells 14 . The method includes maintaining network performance data for the neighboring cells 14 , reflecting historic or expected handover performance for the neighboring cells 14 with respect to the first cell 14 . In particular, the method includes maintaining a cell list 18 of those neighboring cells 14 that are available for handover based on receiving a cell information message from each such neighboring cell 14 that indicates the number (and ID) of served PLMNs available in the neighboring cell 14 . That is, a given base station 12 may receive multiple cell information messages from a given neighboring base station 12 , for a given neighboring cell 14 , with each such message indicating the number (and IDs) of served PLMNs that currently are available in the neighboring cell 14 . In response, the receiving base station 12 processes each such cell information message and updates its list 18 accordingly.
[0032] In particular, the base station 12 or other node maintains a cell list of those neighboring cells that are available for handover based on receiving a cell information message from each such neighboring cell that indicates the neighboring cell has at least one served PLMN available. At some later time, the base station 12 receives a cell information message from a given one of the neighboring cells 14 (Step 100 ), and it processes that message to determine whether there are any served PLMNs available in the reporting cell 14 . If not (“NO” from Step 102 ), the base station 12 removes the neighbor cell 14 from the cell list 18 , or otherwise marks it as unavailable. However, as noted, the base station 12 continues maintaining performance data for the neighboring cell 14 (Step 104 ). On the other hand, if the cell information message indicates that at least one served PLMN is still available in the reporting cell 14 , the base station 12 keeps the reporting cell in its list 18 (Step 106 ).
[0033] As for the reporting cell—i.e., the neighboring cell that generates and sends such cell information messages— FIG. 9 illustrates a method of indicating the loss of served PLMN availability for a given cell in a wireless communication network. The method includes detecting that no served PLMNs are available for use in providing service in the given cell 14 (Step 120 ). The method further includes setting an indicator value to zero, or another value logically deemed to be zero, in response to detecting that no served PLMNs currently are available for providing service in the given cell 14 (Step 122 ), and sending a cell information message to a neighboring cell 14 , said cell information message conveying said indicator value, to inform the neighboring cell 14 that the given cell 14 currently has no served PLMNs available (Step 124 ).
[0034] In at least one embodiment, the above “setting” step comprises an eNodeB associated with the given cell setting a broadcast PLMN information element (IE) in a cell data update message. Correspondingly, the “sending” step comprises the eNodeB transmitting the cell data update message over an X2 interface, to another eNodeB associated with the neighboring cell.
[0035] In the same or another embodiment, the method includes detecting that at least one served PLMN has become available for use in providing service in the given cell 14 , after a time during which no served PLMNs were available for such use. In response to such detection, the method includes setting the indicator to a non-zero value, or another value logically deemed to be non-zero, in response to said detecting served PLMN availability, and sending another cell information message to the neighboring cell, said another cell information message conveying said indicator value, to inform the neighboring cell that the given cell currently has one or more served PLMNs available.
[0036] Implementing the above method or variations of it in the LTE context can be done, at least in part, by modifying the served cell information, as specified in the 3GPP TS 36.423. Namely, the served cell information, such as sent in an inter-cell message over the X2 interface, includes one or more Information Elements (IEs) that can be modified to enable conveying “zero” as the number of available served PLMNs. This is shown in Table 1 below, where the changed parameter(s) are noted via the strikethrough text:
[0000]
TABLE 1
IE type
Criticality/
IE/Group
Pre-
and
Semantics
Assigned
Name
sence
Range
reference
description
Criticality
PCI
M
INTEGER
Physical
—
(0 . . . 503, . . . )
Cell ID
Cell ID
M
ECGI
—
9.2.14
TAC
M
OCTET
Tracking
—
STRING(2)
Area Code
Broadcast PLMNs
Broadcast PLMNs
—
[0037] With this approach, all external cell data can be kept as needed in neighboring eNodeBs, and those neighboring eNodeBs can be informed when a given cell has no served PLMNs currently available in it, so that no HO attempts are made to that given cell with no served PLMNs.
[0038] In another embodiment, a wireless communication node is configured to implement the method of FIG. 9 . For example, the processing circuits 50 of the base station 12 can be configured, e.g., by way of executing stored computer program instructions, to carry out the method of FIG. 9 , in addition to or in alternative to the method of FIG. 8 . In this regard, it will be understood that a given base station 12 may perform the operations of FIG. 8 in the context of receiving cell information messages from one or more neighboring base stations 12 . Conversely, the given base station may perform the operations of FIG. 9 in the context of detecting PLMN availability in one of its own cells 14 , and correspondingly generating and sending cell information messages to neighboring cells, to provide such information to those neighboring cells.
[0039] For either or both methods, those skilled in the art will appreciate that in one or more embodiments the processing circuits 50 of FIG. 7 comprise computer processing circuitry, e.g., one or more microprocessors, digital signal processors, ASICs, or other type of digital processing circuit. In this regard, the base station 12 may store computer program instructions, the execution of which configures the processing circuits 50 to carry out the methods illustrated in FIG. 8 and/or FIG. 9 .
[0040] The present invention may, of course, be carried out in other ways than those specifically set forth herein without departing from essential characteristics of the invention. The present embodiments are to be considered in all respects as illustrative and not restrictive, and all changes coming within the meaning and equivalency range of the appended claims are intended to be embraced therein.
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In one aspect, the teachings herein provide an enhanced inter-base-station interface and associated processing in which a base station receives a message from a neighboring base station that zero served PLMNs are available in a neighboring cell. In response to receiving that message, the base station removes the neighboring cell from its neighbor list, or otherwise marks the neighboring cell as unavailable, but advantageously does not discard any network performance data accumulated or otherwise generated for that neighboring cell. Correspondingly, should the base station receive a subsequent message indicating that one or more served PLMNs have become available in the neighboring cell, it restores the neighboring cell to its neighbor list and reinstates links or associations, as needed, to the retained network performance data.
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The present invention relates to single instruction, multiple data (SIMD) processors. In particular, the present invention relates to rate buffering in digital subscriber line (DSL) systems.
BACKGROUND OF THE INVENTION
A single instruction, multiple data (SIMD) processor essentially consists of a single program control unit (PCU) that controls the data processing of any number of data channels. FIG. 1A illustrates one possible SIMD configuration, represented by the numeral 10 . The PCU 12 is coupled to N data paths 13 , implying a parallel-processing scheme. Each data path 13 is coupled to a data memory 14 and a processor 15 .
FIG. 1B illustrates a second SIMD configuration, represented by the numeral 16 . In this configuration, the sharing of the instruction is done serially by time division multiplexing the processing in a data path 18 for all channels. The data is, therefore, changed N times at the input to the data processor 15 for every instruction that is produced.
The advantages that the SIMD architecture provides are savings in both power consumption and area reduction when compared to a solution using dedicated processors for each data path, or channel. The savings come from having only one PCU 12 and one program memory. If the data path processor is also being time shared, as in FIG. 1B , further savings in area reduction are realized. However, the processor must be able run at higher speeds to accommodate multiple channels. Furthermore, simplifications are also made at a higher level, since there is only one program load to manage and track. Having only one program load reduces start-up times if download times are consuming a large portion of time.
As described in the various standards defining the different flavors of digital subscriber line (DSL) systems, the procedure from power-up to run time operation takes modems through a series of handshakes and initialization procedures. These procedures require the modems to handle different data rates while maintaining a constant carrier frequency profile. In a multiple channel system, the assumption is that all channels may not be in the same state at any given time.
The maintenance of the constant carrier frequencies facilitates reuse of program code to perform some of the necessary tasks such as fast Fourier transforms (FFTs), equalization and the like. However, the changing data rates make it difficult to use one processor for performing symbol-based operations on multiple channels. This is due to the fact that the modem cannot synchronize all channels with its own processing rate since the symbol rate for all channels is not equal. Therefore, the presence of different rates in a multi channel system precludes using a constant rate processor for all channels.
It is an object of the present invention to obviate or mitigate some of the above disadvantages.
BRIEF SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided a single instruction multiple data (SIMD) architecture for controlling the processing of plurality of data streams. The SIMD architecture comprises a memory for storing the data from the channels, a processor operatively coupled with the memory for processing data from the data streams, and a controller for controlling the processor. Storing the data in the memory de-couples the operating rate of the processor and the operating rate of the data streams.
In accordance with a further aspect of the present invention, there is provided a method for controlling the processing of multiple data streams in a SIMD architecture. The method comprises the steps of storing data in a memory as it is received; determining, at predetermined times, whether all of said data has been received; providing a signal indicating that all of the data has been received; using the signal to determine which data to process; and processing the data.
BRIEF DESCRIPTION OF THE DRAWINGS
An embodiment of the invention will now be described by way of example only with reference to the following drawings, in which:
FIG. 1A is a block diagram of a standard SIMD architecture with multiple data paths;
FIG. 1B is a block diagram of a standard SIMD architecture with a single, time-shared data path;
FIG. 2 is a block diagram of a circular buffer architecture; and
FIG. 3 is a block diagram of a SIMD architecture according to an embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
For convenience, in the following description like numerals refer to like structures in the drawings.
FIG. 2 illustrates a circular buffer architecture, represented generally by the numeral 20 . The circular buffer 20 is partitioned into three distinct sections. The first section 22 is for pre-processed symbols, the second section 24 is for present symbol processing, and the third section 26 is for post-processed symbol extraction. A symbol manager 28 is used for managing the locations of these symbols.
The buffer 20 may include an elastic region that is able to absorb data growth or depletion due to differences in rates of the three devices (output device, input device, and processor) that use the buffer 20 . This region may hold up to one symbol, and may be located within the first section 22 .
FIG. 3 illustrates a SIMD architecture, represented by the numeral 36 . The architecture 36 includes a PCU 12 , multiple data paths 13 , multiple data memories 14 and multiple processors 15 . The architecture also includes enable signals 32 , coupled to the processors 15 .
Referring to FIG. 2 , data is typically input serially into the pre-processed section 22 . Once the data has been received, it is rotated to the present symbol processing section 24 , where it is parallel-processed. Once the processing is complete, the symbol is rotated to the post-processed section 26 of the buffer 20 , where it is output serially. Although the symbol is rotated through several sections of the buffer 20 , its physical location does not necessarily chance. Changing the location of the symbol can be done; however, it would require more time and more memory.
Maintaining the same location for a particular symbol is accomplished since the buffer 20 is circular. Rather than have the address of the symbol physically rotate, the sections 22 , 24 , and 26 of the buffer 20 rotate about predetermined addresses. Therefore, an address that points to an incoming symbol is in the pre-processed section 22 . Once the symbol has completely arrived and is being processed, the address that points to that symbol is in the processing section 24 . Once the symbol has been processed, that address is considered to be in the post-processed section 26 .
The symbol manager 28 locates the base address for each of the symbols, allowing the circular nature of the buffer 20 to be transparent to each device accessing the data. The input data enters the buffer 20 at an arbitrary data rate. The data is loaded sequentially into the pre-processed section 22 until a complete symbol is collected. At that point, the symbol manager 28 advances to the next base pointer location.
(As an added feature, the address generation unit can access the buffer 20 directly with the address offset from the processor without the addition of the base address from the symbol manager 28 , by way of a switch. This allows the processor 15 to bypass the symbol manager 28 and access the buffer 28 absolutely.)
The PCU 12 indicates the start of a processing cycle with a start of processing (SOP) pulse. At each SOP pulse, the base pointer for the processing section 24 is compared to the base pointer for the incoming symbol (in the pre-processed section 22 ). The difference between these base pointers indicates whether or not a full symbol is ready for processing. If a full symbol is present, the enable signal 32 (shown in FIG. 3 ) for that symbol is activated. Otherwise, the enable signal 32 remains inactive and the comparison is done again at the next SOP. Therefore, only the processors 15 that have received a complete symbol are enabled.
As each of the devices completes processing its respective symbol, the symbol manager 28 advances the base pointer of the processing section 24 to the next symbol. Once the base pointer of the processing section 24 advances, the processed symbol is in the post-processed section 26 . The extraction of the post-processed data is slaved to the processor 15 , and is only performed after the symbol has been processed.
An advantage of this type of buffering scheme is that the processor is de-coupled from the incoming data rate of each channel. This is true with the restriction that the SOP of the processor is greater than or equal to the maximum baud rate of the channels. If this were not true, it is possible that incoming data could overwrite previously received data before it is processed. Therefore, the net processing rate of each channel is approximately equal to the baud rate for that channel since its processor 15 may be periodically disabled.
The rate at which any given channel is disabled (assuming zero jitter between each of the baud rates) is given by:
%
PROC
OFF
=
Fbaud
SOP
-
Fbaud
CHAN
Fbaud
SOP
This equation also indicates the “bursty” nature of the data output rate. That is, the output is provided in bursts—when the processor is enabled—rather than a constant steady stream. Also, the varying instantaneous latency due to the gapped processing can be determined.
Since the data is assumed to be arriving at a constant input rate, any gaps in the processing increase buffering requirements. However, since the worst case, or fastest, baud rate of the channel is equal to the baud rate of the processor, the buffering requirement is limited to the symbol size for each of the three sections 22 , 24 , and 26 .
Implementing an SIMD in this manner provides several advantages. The architecture ultimately results in a net decrease in gate count and expended power, since the processors are only used for completely received symbols. Buffering requirements can be combined with those necessary for other considerations in the signal processing. Therefore, little or no extra memory is required. The structure can be applied to any symbol size. This includes processing on a sample by sample basis. The structure can be expanded to accommodate any number of channels. Lastly, this structure has direct applications to implementations of ITU G.992.2 (and other standards) for DSL systems, since the baud rate changes throughout operation.
In an alternate embodiment, it is possible that the data is received in parallel and the output transmitted in parallel.
In yet another embodiment, it is possible that the data is received serially and the output transmitted in parallel.
In yet another embodiment, it is possible that the data is received in parallel and the output transmitted serially.
It is possible to implement the system as described above using other SIMD implementations and will be apparent to a person skilled in the art.
Although the invention has been described with reference to certain specific embodiments, various modifications thereof will be apparent to those skilled in the art without departing from the spirit and scope of the invention as outlined in the claims appended hereto.
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A single instruction, multiple data (SIMD) architecture for controlling the processing of plurality of data streams in a digital subscriber line (DSL) system has a memory for storing the data from the channels, a processor operatively coupled with the memory for processing data from the data streams, and a controller for controlling the processor. Storing the data in the memory de-couples the operating rate of the processor and the operating rate of the data streams.
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CROSS-REFERENCE TO RELATED PATENT APPLICATION
This application is related to a commonly assigned copending U.S. patent application Ser. No. 07/351,686, filed May 15, 1989, now U.S. Pat. No. 4,959,540 and entitled "Optical Clock System for Computers", by B. Fan et al.
FIELD OF THE INVENTION
This invention relates generally to optoelectronic devices and, in particular, to a high-speed, low-jitter toggle Flip-Flop (F/F) device coupled to an optical pulse source for converting an optical pulse into electrical signals.
BACKGROUND OF THE INVENTION
The electrical transmission of fast timing signals introduces timing skew problems resulting from the limited bandwidth associated with the transmission and reception of the electrical signals through conventional electrical cables and transmission lines. One especially deleterious effect of the limited bandwidth is a degradation of fast risetime pulses. As a result, a variation in pulse receiver sensitivity or threshold causes an uncertainty or jitter as to an actual time of the arrival of electrical pulse. If the electrical pulse is being employed as a timing signal in, for example, a high-speed data processing system the presence of pulse jitter is especially detrimental.
FIG. 1 illustrates a simplified diagram of a conventional toggle circuit constructed as a set-reset flip-flop (SR-F/F). The SR-F/F includes two transistors Q A and Q B interconnected in a cross-coupled manner as shown. Each transistor is further coupled to a source of operating power (V dd ) through an associated load resistance R A and R B . In operation an electrical pulse to INPUT A sets OUTPUT logically HIGH, while an electrical pulse to INPUT B resets the OUTPUT logically LOW. The complementary signal OUTPUT* is LOW when OUTPUT is HIGH and vice versa. One advantage of such a SR-F/F circuit is that the output is always in a known logical state, as is important in the clocking of a computer system. That is, the OUTPUT signal may be employed as a clocking signal for logic circuitry of a computer system.
However, as was previously stated the electrical transmission of fast timing signals introduces timing skew problems resulting from the limited bandwidth associated with the transmission and reception of the electrical signals through conventional electrical cables and transmission lines. That is, if the electrical pulse signals coupled to INPUT A and INPUT B are transmitted through conventional electrical signal transmission means there is a limitation on an upper useable frequency that can be provided to the SR-F/F before the degradation of output pulses and increased output jitter become unacceptable. A problem is created if this upper usable frequency is below a frequency at which it is desired to clock associated logic circuits.
One proposed solution to this problem involves transmitting the input pulses as an optical signal instead of an electrical signal. For example, due to the inherently much wider bandwidth of an optical fiber the transmission of a fast rise time optical pulse through the fiber occurs without significant signal degradation. However, a problem is created when it is required to convert the optical pulse into an electrical signal for interfacing to logic circuits such as the SR-F/F in that optoelectronic circuits generally include electrical switching circuitry coupled to an optical receiver. The receiver typically includes a photosensor followed by several gain stages with output of the gain stages being applied to the associated switching circuitry. A problem with this conventional arrangement relates to the propagation delay between a time light is incident upon the photosensor and a time at which the switching circuit responds by changing state. Another problem relates to temporal jitter resulting from uncertainty in the propagation delay produced by the gain stages proceeding the logic circuitry.
In U.S. Pat. No. 3,686,645, entitled "Charge Storage Flip-Flop" and issued Aug. 22, 1972, Brojdo teaches a semiconductor memory array using a pair of bipolar transistors arranged as a F/F wherein a base of each transistor is connected to a high impedance when a power supply voltage is removed. As the high impedance forces slow decay of charge stored in the transistors, the state of the F/F can be maintained by a pulsed power supply, thereby reducing the average power dissipation of the F/F. Using the photosensitive nature of the transistors, the memory can be written optically by photogenerating charge in the base of one of the transistors, thereby unbalancing the transistors. A laser is employed to address a hologram for providing a desired light pattern for illuminating the memory array. This device specifically uses the low speed nature of the high impedance circuits to integrate the optical signals being applied. Thus, although a F/F circuit configuration is used the application and nature of operation do not address the problem of converting optical pulses into fast rise-time, low jitter electrical logic signals.
In U.S. Pat. No. 4,023,887, entitled "Optical Communication, Switching and Control Apparatus and Systems and Modular Electro-optical Logic Circuits, and Applications thereof" and issued May 17, 1977, Speers discloses optical communication, switching and control apparatus and system, including modular electro-optical logic circuits An optical F--F depicted in FIGS. 38a and 38b and described at Col. 23, lines 3-53 has one optical input and one optical output, and functions basically an optical "repeater" amplifier. It is noted that Speers teaches a binary device wherein the output frequency is one half of the input frequency and individual pulse timing is not preserved. This device is not believed to be suitable for fast rise-time/fall-time, low jitter applications.
The following U.S. Patents are noted of being of general interest. U.S. Pat. No. 4,223,330, entitled "Solid-State Imaging Device", describes a solid-state image pickup device for use in a TV camera and the like. U.S. Pat. No. 4,295,058, entitled "Radiant Energy Activated Semiconductor Switch", describes various power switching circuits using a light sensor such as photodiode coupled to a gate of a depletion-mode FET. U.S. Pat. No. 4,390,790, entitled "Solid State Optically Coupled Electrical Power Switch", relates to optically isolated switching devices such as solid-state relays for power switching or analog switches for signal switching. U.S. Pat. No. 4,521,888, entitled "Semiconductor Device Integrating a Laser and a Transistor", teaches an integrated semiconductor device including a diode laser and a transistor for modulating the laser. U.S Pat. No. 4,739,306, entitled "Calibrated-Weight Balance and an Analog-to-Digital Converter in which the Balance is Employed", discloses a calibrated-weight balance for the construction of very-high-speed analog-to-digital converters (ADC). The circuit includes a multivibrator comprising cross-coupled FETs 15 and 16. However, this Patent does not disclose the provision of optical inputs for driving the multivibrator.
It is thus an object of the invention to provide an optoelectronic pulse converter for converting an optical pulse into an electrical pulse having a fast risetime and a minimum of timing uncertainty.
It is a further object of the invention to provide a timing generation circuit that provides for the transmission of optical pulses of ultrafast risetime through extremely high-bandwidth optical fibers and which further converts these optical pulses into an electrical timing signal having leading and trailing edges exhibiting minimal timing uncertainty.
It is one further object of the invention to provide clock generation circuitry for a high-speed, short cycle time data processor that employs the transmission of optical clock synchronization pulses of ultrafast risetime through extremely high-bandwidth optical fibers and which further converts these optical pulses into an electrical clock signal having a minimal pulse skew.
SUMMARY OF THE INVENTION
The foregoing problems are overcome and the objects of the invention are realized by a high speed clock generator integrated circuit for generating a periodic electrical signal. The circuit operates as a pulse converter and converts optical pulses to electrical pulses.
The pulse converter includes a set-reset flip/flop, or OPTOGLE, having a pair of cross-coupled switching devices such as transistors or logic gates. The converter operates by coupling pulses of optical radiation to each of the switching devices for causing the switching devices to alternately toggle between an on-state and an off-state. Optical inputting devices such as photodiodes or photoconductors, or the gates of FET transistors themselves, are integrally formed upon a common substrate with the switching devices for minimizing stray inductive and capacitive reactances to substantially eliminate temporal jitter in an electrical output signal. A pulsed laser source and a fiber optic or optical waveguide provide non-overlapping optical pulses to each of the switching devices.
In accordance with one embodiment each of the switching devices is a GaAs MESFET device having a gate terminal comprised of a substantially transparent layer of electrical conductor having an interdigitated geometry and an overlying anti-reflection (AR) coating.
In this embodiment the transistors are each constructed of a semiconductor material having a characteristic energy bandgap for absorbing the optical pulse and generate sufficient charge carriers therefrom to induce a current flow though the transistor. The semiconductor material may be comprised of Group III-V material, of silicon, of other Group IV materials such as germanium or of combinations of these materials.
BRIEF DESCRIPTION OF THE DRAWING
The above set forth and other features of the invention are made more apparent in the ensuing Detailed Description of the Invention when read in conjunction with the attached Drawing, wherein:
FIG. 1 is a schematic diagram of a conventional two-input, two-output toggle circuit implemented as set-reset F/F;
FIG. 2 is a schematic diagram of a toggle circuit also implemented as set-reset F/F but which includes first and second optical inputs for changing the state of the F/F;
FIG. 3 illustrates the illumination of an interdigitated gate of a GaAs MESFET with an optical input signal for changing the state of the set-reset F/F of which the MESFET is a part;
FIG. 4 is a block diagram illustrating experimental apparatus for coupling high speed optical pulses to the optical toggle circuit of the invention;
FIG. 5 illustrates graphically an output electrical pulse of the optical toggle circuit in response to an input optical pulse, the x-axis divisions each indicating 500 picoseconds (500×10 -12 sec.);
FIG. 6 illustrates graphically the OUTPUT signal changing state in response to the optical pulses applied to OPTICAL INPUTs A and B;
FIGS. 7a, 7b, 7c and 7d illustrate various methods for coupling optical pulses to inputs of the optical toggle circuit;
FIG. 8a is a schematic diagram of a toggle circuit implemented as a set-reset F/F and including integrated photodiodes for coupling first and the second optical inputs to associated switching transistors for changing the state of the F/F;
FIG. 8b is a schematic diagram of a toggle circuit implemented as a set-reset F/F and including integrated photoconductors for coupling first and the second optical inputs to associated switching transistors for changing the state of the F/F; and
FIG. 9 is a schematic diagram of a toggle circuit implemented as a set-reset F/F including integrated photodiodes for coupling the optical inputs and further incorporating cross-coupled NOR-gate function devices in place of cross-coupled switching transistors.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to FIG. 2 there is shown a SR-F/F that operates in accordance with one embodiment of the invention. The SR-F/F is an optically-toggled device and is referred to herein as an OPTOGLE 10. OPTOGLE 10 is constructed in some respects in a similar manner to the circuit of FIG. 1. OPTOGLE 10 includes two transistors Q 1 and Q 2 having their respective gate terminals interconnected in a cross-coupled manner as shown. Each transistor further has a drain terminal coupled to a source of operating power (V dd ) through an associated load, such as a resistance R 1 and R 2 , and a source terminal coupled to a common potential. While the OPTOGLE 10 may be implemented in a wide variety of semiconductor device technologies, in a presently preferred embodiment of the invention the transistors are MESFET devices comprised of semiconductor material having a high electron mobility, such as GaAs.
By example, C. Baack et al. in a journal article entitled "GaAs M.E.S.F.E.T.: A High-Speed Optical Detector", Electron. Lett., 13, 193(1977) report a GaAs MESFET photoresponse of less than 75 picoseconds.
In accordance with one embodiment of the invention a region between the source and drain of each MESFET is illuminated with a light pulse of narrow pulsewidth to achieve a high frequency of operation. Preferably the source of the light is a laser source such as a mode-locked gas laser, a mode-locked solid-state laser, or a gain-switched semiconductor diode laser as disclosed in commonly assigned U.S. patent application Ser. No. 07/351,686, filed 5/15/89. Due to the nature of the optical input, the MESFETs have an equivalent fourth port that is highly isolated from the gate, drain and source terminals. This equivalent fourth port is shown schematically in FIG. 2 and is referred to as OPTICAL INPUT A and OPTICAL INPUT B.
If the incident photon energy is greater than the semiconductor bandgap, a large density of charge carriers is generated. These charge carriers produce fast electrical pulses between the drain and source terminals of the FET by means of photoconductivity. In that the optical pulsewidth is preferably much shorter than the charge carrier lifetime, this effect is transient. In general, a risetime of the photoconductive signal is approximately the same as a risetime of the optical pulse while the fall time of the photoconductive signal is a function of the charge carrier lifetime. The photoconductive gain, defined as the number of charge carriers crossing a sample per second divided by the number of photons absorbed per second, is approximately the ratio of optical pulse duration to the transit time of the charge. As a result a large gain may be realized. The light-induced electrical pulse controls the output state of the OPTOGLE 10 in substantially the same manner as the electrical inputs INPUT A and INPUT B, and may be used interchangeably if desired. It should be noted that both electrical and optical inhibit capability is implicit in the circuit in that toggle activity can be inhibited by the application of a long duration pulse, or level, through either the electrical or the optical inputs. In general the transistor gates serve several purposes including providing positive feedback during changes of state and also providing external electrical terminals.
As shown in FIG. 6 an optical pulse applied to OPTICAL INPUT A sets OUTPUT logically HIGH, while an optical pulse applied to OPTICAL INPUT B resets the OUTPUT logically LOW. As was stated, electrical pulses could be substituted for some of the optical pulses or could be used to inhibit the operation of the optical pulses. The optical pulses may be derived from separate sources or from a common source. If the latter approach is employed one of the pulses is passed through an optical delay device, such as longer path length optical fiber, so that the second pulse is temporally offset from the first pulse by a desired amount. The amount of temporal offset affects the output electrical signal duty cycle as shown.
One significant advantage of directly coupling the light pulse to the gates of the transistors of the OPTOGLE 10 is the resulting simplicity of the circuit. That is, the MESFET itself functions as a photosensor and, with no signal amplifying or conditioning stage(s) required as with conventional types of optoelectronic devices, the propagation delay and the temporal jitter is minimized. Thus, the OPTOGLE 10 significantly reduces pulse skew characteristics which are especially critical in data processing clock signal distribution.
The operation of the OPTOGLE 10 has been experimentally demonstrated with commercially available GaAs digital integrated circuits constructed with depletion-mode MESFETs. FIG. 3 illustrates an enlarged view of a portion of an interdigitated MESFET. In this device the gate electrode 12a is disposed between the source electrode 12b and the drain electrode 12c. An illuminating laser beam spot 14 has a diameter of approximately 30 microns. The interdigitated geometry of the gate electrode 12a beneficially reduces shadow effects of the electrodes, thus improving light coupling, while also providing for a low interelectrode capacitance. The provision of an anti-reflection (AR)-coating 18 over the gate electrode 12a further improves light coupling efficiency, the AR coating being optimized for the wavelength of the incident optical radiation. Coupling efficiency may be further improved with transistor gates constructed of semitransparent electrodes such as electrodes comprised of a relatively thin layer of metal having a thickness of approximately 100 Angstroms. In accordance with an aspect of the invention the MESFETs Q1 and Q2, associated electrodes 12a, 12b, 12c and other components are formed on a common substrate 16.
The characteristics of the GaAs OPTOGLE 10 were determined with the experimental apparatus 20 schematically shown in FIG. 4. The apparatus 20 includes a pair of optical fibers 22a and 22b each of which conveys light from an associated source 24a and 24b. Sources 24a and 24b are preferably each a coherent source. An output end of each the fibers 22 is coupled to a collimating lens 26 from which the light energy is relayed to a dichroic mirror 28. Optically coupled to one side of the dichroic mirror 28 is a focusing lens 30 for focusing the outputs of the sources 24 onto respective gate electrodes of an integrated circuit device 32 containing the OPTOGLE 10. Optically coupled to the opposite side of the dichroic mirror 28 is a beamsplitter 34. An illuminator 36 for camera 40 provides illumination through a collimating lens 36. Camera 40 views the scene through a focusing lens 42. This arrangement permits the optical stimulation of the OPTOGLE 10 and the simultaneous viewing by the camera 40.
FIG. 5 illustrates the OUTPUT signal of the OPTOGLE 10. Each time division along the x-axis represents 500 picoseconds. The input pulse is the input electrical pulse applied to a laser diode source in order to generate the optical pulse that was applied to the OPTOGLE 10.
Suitable sources of radiation include mode-locked Nd:Yag lasers, Nd:YLF lasers, AlGaAs diode lasers or any source capable of generating ultrashort, fast risetime, high-peak-power optical pulses at a high repetition rate. The wavelength of the pulse is preferably within a range of wavelengths strongly absorbed by the semiconductor material For example, both GaAs and silicon strongly absorb visible and near-infrared radiation. With known types of optical pulse compression techniques using optical fibers and gratings a duration of the optical pulses can be reduced to the subpicosecond range. The GaAs MESFET-based OPTOGLE 10, although not entirely optimized for such operation, has been found to require a pulse energy of 4 pJoules. As an example, operation at 250 MHz requires an average optical power of 1 mWatt at each of the two OPTOGLE 10 receiving sites. Thus, a mode-locked laser with average output power of 1 Watt has sufficient power to simultaneously address approximately 500 of the OPTOGLE pulse converters. For example, the gate electrodes of two MESFET devices were illuminated with laser beam pulses having an approximately 30 micron spot size. The light pulses were produced by injecting a train of 250 picosecond electrical pulses into an AlGaAs diode laser having a nominal wavelength of 780 nanometers. The optical pulses were provided through fiber optics as depicted in FIG. 4.
In addition to the photo-FET implementation described in detail above the SR-F/F may be implemented in various technologies. By example, FIG. 8a shows a FET flip-flop with photodiode inputs. Preferably, the photodiodes D1 and D2 are integrated into the same substrate as the FETs Q1 and Q2 and the other components of the SR-F/F. One important advantage of this technique is the reduction of required circuit dimensions with a corresponding reduction of stray circuit reactances, both capacitive and inductive, at the photosensor leads. As a result optical input pulses are efficiently received and circuit speeds are very fast. Of course, any of the SR-F/F embodiments may be implemented with bipolar transistor technology, instead of the FET technology shown.
Also, the SR-F/F may be implemented by more general logic devices, such as the NOR gates (G1 and G2) shown in FIG. 9. This embodiment also includes integrally formed photodiodes D1 and D2 and is implemented as an integrated photosensor/logic circuit combination to achieve fast switching times.
If desired, the use of photovoltaic optical sensors such as the photodiodes D1 and D2 may be replaced, as in FIG. 8b, by integrated photoconductive sensors (S1 and S2). Such devices, such as those constructed of Group III-V, silicon and other materials exhibit very fast (picosecond) response times and are well suited for this use.
In all embodiments of the invention an important aspect is the integration of the photosensor devices with the cross-coupled switching circuitry, with no additional amplifier circuits being required or deployed, thereby significantly reducing temporal jitter in the output pulse stream.
It should be noted that for application of the OPTOGLE to a data processor that the optical pulses may be applied, as depicted in FIGS. 7a-7d, through optical fibers 50a and 50b having flat, polished ends (FIG. 7a) or integral focusing optics (FIG. 7b). In these two embodiments the fiber 50a and 50b ends are bonded or otherwise fixedly coupled to the appropriate electrode region of each of the transistors Q1 and Q2 or to the associated one of the photodiodes D1 or D2 or photoconductors S1 or S2. Either single mode or multi-mode optical fibers are suitable for this task. FIG. 7c illustrates the fibers 50a and 50b having a beveled end and coupled to a v-block. The beveled fiber ends serve as reflectors for coupling the optical inputs to, for example, the photodetectors D1 and D2. FIG. 7d illustrates an optical waveguide 54 fabricated upon the substrate 16 and having an end in optical communication with the SR-F/F for coupling optical pulses thereto. It is also within the scope of the invention to convey the optical radiation to the transistors by integrating, for example, a plurality of AlGaAs laser devices onto an integrated circuit device with the OPTOGLE 10.
OPTOGLEs may be constructed with silicon FET technology although such devices exhibit a slower response due to relatively lower carrier mobility than similar devices constructed with GaAs and/or other Group III-V materials such as InP.
By example and referring to the embodiment of FIGS. 2 and 3 with GaAs material electron mobility is approximately 8600 cm 2 /Vs and electron transit time is approximately 15 picoseconds for an electrode 12 spacing of five microns and an applied voltage of two volts. The gain is approximately 10 for laser pulses of 150 picoseconds in duration. Modulation of the gate 12a voltage during operation also results in a current amplification.
Thus, while the invention has been particularly shown and described with respect to preferred embodiments thereof, it will be understood by those skilled in the art that changes in form and details may be made therein without departing from the scope and spirit of the invention.
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A pulse converter includes a set-reset flip/flop, or OPTOGLE 10, having a pair of cross-coupled switching devices such as transistors Q1, Q2 or logic gates G1, G2. The circuit operates by coupling pulses of optical radiation to each of the devices for causing the devices to alternately toggle between an on-state and an off-state. Optical inputting devices such as photodiodes or photoconductors, or the gates of FET transistors themselves, are integrally formed upon a common substrate with the switching devices for minimizing stray inductive and capacitive reactances to substantially eliminate temporal jitter in an electrical output signal. A pulsed laser source and a fiber optic or optical waveguide provide non-overlapping optical pulses to each of the switching devices. In accordance with one embodiment each of the switching devices is a GaAs MESFET device having a gate terminal comprised of a substantially transparent layer of electrical conductor having an interdigitated geometry and an overlying anti-reflection (AR) coating.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of application Ser. No. 13/371,842, filed Feb. 13, 2012 now U.S. Pat. No. 8,249,959, which is a continuation of application Ser. No. 12/805,437, filed Jul. 30, 2010 now U.S. Pat. No. 8,145,547, which is a continuation of application Ser. No. 09/902,707, filed Jul. 12, 2001 now U.S. Pat. No. 7,793,331, which is a continuation of application Ser. No. 08/817,528, filed Aug. 5, 1997 now U.S. Pat. No. 6,308,204, which claims priority to International Application No. PCT/FR94/01185, filed Oct. 12, 1994, and French Application No. 95/08391, filed Jul. 11, 1996, the entire contents of each of which are incorporated herein in its entirety by reference.
This application is related to our co-pending commonly assigned applications:
U.S. Ser. No. 08/817,690
(Corres. to PCT/FR94/01185
filed Oct. 12, 1994);
U.S. Ser. No. 08/817,689
(Corres. to PCT/FR95/01333
filed Oct. 12, 1995);
U.S. Ser. No. 08/817,968
(Corres. to PCT/FR95/01335
filed Oct. 12, 1995);
U.S. Ser. No. 08/817,437
(Corres. to PCT/FR95/01336
filed Oct. 12, 1995)
U.S. Ser. No. 08/817,426
(Corres. to PCT/FR95/01337
filed Oct. 12, 1995); and
U.S. Ser. No. 08/817,438
(Corres. to PCT/FR95/01338
filed Oct. 12, 1995).
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to a communications process for a payment—triggered audiovisual reproduction system.
These audiovisual reproduction systems are generally found in cafes or pubs. This type of system is composed of a sound reproduction machine usually called a jukebox linked to a monitor which displays video images or video clips. To do this the jukebox is equipped with a compact video disk player and a compact video disk library and includes selection buttons which locate the titles of pieces of music which are available. Payment of a proper fee followed by one or more selections authorizes activation of the system with automatic loading in the player of the disk on which the selected piece is found, the desired audiovisual reproduction then being able to start.
These systems, although allowing faithful and good quality reproduction, nevertheless have major defects. Thus, a first defect relates to the space necessary for storing the library; this consequently entails that the system will have large dimensions and will be bulky. Likewise these systems which call on mostly mechanical hardware using sophisticated techniques have high fault rates; this is another defect. Finally, it is very unusual for all the pieces on a disk to be regularly heard; some are almost never played, but still cannot be eliminated. Besides this defect, the additional problems are caused by the companies which manage and distribute these systems. More particularly, placing in the circuit a limited number of identical disks and imposing a certain rotation on their customers sometimes results in an unpleasant wait for the customers when a disk is not available.
In addition, patent application PCT/WO 93 18465 discloses computerized jukeboxes which allow reception via a telecommunications network and a modem connecting the jukeboxes to the network, digital data comprising remotely loaded songs or musical pieces in a mass storage of the jukeboxes. The communications systems is likewise used for remote loading of representative files of digitized graphics information, the songs and graphics files being compressed before they are sent over the network. The jukebox processor then uses these files by decompressing them and sending the graphics data to the video circuit and the song data to the audio circuit.
However, the processor also manages the man/machine interface, and management of these different elements is done by sequentially displaying the graphics images representative of the song, then by responding to the touch action of the user, then checking that the user has paid the prescribed amounts, and finally when the required amount has been accounted, placing the selection in a queue for its subsequent performance. This system can only operate by first displaying the graphics images and then starting performance of the song because the processor cannot, according to the flowcharts, execute two tasks at one time. Finally, the graphics representations are uniquely data digitized by a scanner table of the album cover of the song. In no case does this jukebox allow display of moving images during the broadcast of the song or music. Likewise, since the processor is used for digital data decompression and processing for conversion into audio signals, it cannot consider the new actions of a user making a new selection. This is apparent, notably on page 12 of the PCT application, lines 25 to 27. Selection of new songs can only be done when the jukebox is in the attraction mode, i.e., the mode in which it displays graphics representations of different songs stored in the jukebox in succession.
U.S. Pat. No. 4,956,768 discloses a broadband server for transmitting music or images formed by a main processor communicating by a DMA channel with a hard disk and output cards, each controlled by a supplementary local processor which manages an alternative mode of access to two buffer memories A and B. Memory A is used to deliver, for example, musical data to a user, while the other is filled. Each of the output cards is connected to a consultation station, which can be local and situated in the same vicinity as the server or, alternatively, at a distance and connected by an audio or video communications network. The server receives data block-by-block and ensures that the sample parities are correct and rejects a block including more than two successive wrong samples. Each of these blocks is of course designated by a number. Once a block has been accepted, it can be stored on the local hard disk by recording its ordinal number which has no relation to its physical address on the hard disk. The consultation stations have audio and video outputs such as loudspeakers or headphones and a television monitor which makes it possible to listen to music or display images in response to requests received from terminals included in the consultation stations. In this system, the consultation stations where the first communications processor exists must have specific software for management of selection requests for musical pieces or video. It is only when the request has been made and addressed to the broadband server processor that it can transfer, under the authority of the local processor, the data in the buffer memories, such that this local processor ensures that the data are sent to the consultation stations. Moreover, it is specified that the output cards and buffer memories are filled only after having received the authorization of the local processor of the card.
Consequently, this system can only function within the framework of a multiprocessor device and does not in any way suggest use of this server for a jukebox controlled by a single processor operating in an multitask environment. This system proposed by this U.S. patent thus implements a complex process which allows delivery of a service to several consultation stations; this complex process is thus costly and incompatible with a system of jukeboxes, of which the cost and price should be as low as possible.
Moreover the process of downloading by a central site of digitized audio and video files to the local servers is accomplished via a specialized line communicating unidirectionally with the V35 interfaces of the local server, and allowing passage of 64 kilobit frames. Thus a second parallel communication must be established via the switched telephone network by a serial interface to allow exchange of service data. It is specified that it is preferable to transmit new musical pieces to the broadband server at night to leave the system free for users during the day, and that transmission can be done continuously and simultaneously for all local servers, provided that they can register continuously, i.e., at night.
This device can only work to the extent that the central server is the master and the local servers are slaved. This thus entails availability of local servers at the instant of establishing communications; this is enabled by the local servers having a double processor which relieves the communication processor for a sufficient interval. In a single—processor architecture it is thus difficult to establish communications according to this protocol determined with a variable number of jukebox stations to allow remote operations such as downloading of music or video following a selection by the jukebox manager or sending statistics to the center, or recovering data concerning billing or security management of the units, or recovery for analysis and survey distribution.
The object of the invention is to eliminate the various aforementioned defects of the systems of the prior art, and to provide a system of communications between jukebox units allowing reproduction and display of audiovisual digital information and a central server which supports, among various functions, downloading of data.
This object is achieved by the communications process operating in a conference mode and it includes the following stages:
sending a heading before any transaction which includes the identity of the destination, identity of the sender, and the size of the packets; sending a server response in the form of a packet of data, each packet sent by the server being encoded using the identification code of the jukebox software; receiving a data packet by the decoding jukebox, wherein the packet at the same time checks the data received using the CRC method and sending a reception acknowledgment to the server indicating the accuracy of the received data to allow it to prepare and send a new packet to the unit destination.
According to another operating mode the server can send the data by stream, the stream including several packets, and the receiver unit will then perform decoding and storage, and after receiving the indicator of the last packet, will signal the defective packets received at the server.
According to another feature, each packet contains a first field allowing identification of the seller, a second field allowing indication of the identification of an application, this 32 bit field making it possible to specify whether it is a digital song, digital video, stationary image, software update, statistics, billing, or update of the unit database, a third field indicating the identification of a single type of application such as the identification number of the product, the type of billing, the difference between a midi song and a digital song, last block indication, finally a fourth field indicating the sequence number of the block in the transmission, a fifth block indicating the length of this block in octets, a sixth field composed of variable length data, a seventh field composed of cyclic redundancy verification data.
An object of the invention is to eliminate the various defects of the systems of the prior art by providing an intelligent digital audiovisual reproduction system which is practical to implement, compact, reliable, authorizes storage at the title level as well as easy deletion or insertion of titles not listened to or wanted, all this while maintaining performance and a high level of reproduction quality.
Another object of the invention is to provide a standard protocol which moreover allows the features mentioned above for remote updating of software.
The objects are achieved by the fact that the jukebox units contain software for interpretation of the second field of the communications packets which detect the code corresponding to remote updating of the software and after having verified that the software version number is greater than the version installed on the unit, initiates a system status verification procedure to ensure than there is no activity underway on the jukebox. If yes, the unit displays a wait message, during reception of the new software version on the screen, copies the back—up of the software version installed on the unit, modifies the system startup file for startup with the backup version, then begins execution of the new version of the software, verifies the state of system status after execution of this new version, reinitializes the system startup files for startup with the new version. In the case in which the status is not OK, the software reinitializes the system with the old version and signals a reception error to the central server.
According to another feature, each audiovisual reproduction system contains a multitask operating system which manages, using a primary microprocessor, the video task, the audio task, the telecommunications task, the input task (keyboard, screen, touch) and a status buffer is linked to each of the tasks to represent the activity or inactivity of this task.
BRIEF DESCRIPTION OF THE DRAWINGS
Other advantages and features of the invention follow from the following description, with reference to the attached drawings, given by way of a non-limiting example only, in which:
FIG. 1 shows a circuit diagram of the hardware comprising the invention;
FIG. 2 shows an organizational chart of the service modules specific to a task and managed via a multitask operating system, the set of modules being included in a library stored in the storage means;
FIG. 3 shows the organization of the multitask system which manages the set of hardware and software;
FIG. 4 shows a flowchart describing the operation of the multitask management system;
FIG. 5 shows a flowchart for verifying task activity;
FIG. 6 schematically shows the database structure;
FIG. 7 shows the structure of the packets used in the communications protocol;
FIG. 8 shows a method of updating the software which can be done using the invention protocol.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Preferably, but in a nonrestrictive manner, the audiovisual reproduction system uses the aforementioned listed components.
Microprocessor central unit 1 is a high performance PC-compatible system, the choice for the exemplary embodiment being an Intel 80486 DX/2 system which has storage means and the following characteristics:
compatibility with the local Vesa bus, processor cache memory: 256 kO, RAM of 32 MO high performance parallel and serial ports, SVGA microprocessor graphics adapter, type SCSI/2 bus type controller, battery backed-up static RAM
Any other central unit with similar, equivalent or superior performance can be used in accordance with the invention.
This central unit controls and manages audio control circuit ( 5 ), telecommunications control circuit ( 4 ), input control circuit ( 3 ), mass storage control circuit ( 2 ), and display means control circuit ( 6 ). The display means consist essentially of a 14 inch (35.56 cm) flat screen video monitor ( 62 ) without interleaving of the SVGA type, with high resolution and low radiation, which is used for video reproduction (for example, the covers of the albums of the musical selections), graphics or video clips.
Likewise comprising part of the storage means, storage modules ( 21 ) using hard disks of the high speed and high capacity SCSI type are connected to the storage means already present in the microprocessor device. These modules allow storage of audiovisual data.
High speed 28.8 k/bps telecommunications modem adapter ( 41 ) is integrated to authorize the connection to the audiovisual data distribution network controlled by a central server.
To reproduce the audio data of the musical selections, the system includes loudspeakers ( 54 ) which receive the signal from tuner amplifier ( 53 ) connected to electronic circuit ( 5 ) of the music synthesizer type provided to support a large number of input sources, while providing an output with CD (compact disk) type quality, such as for example a microprocessor multimedia audio adapter of the “Sound Blaster” card type SBP32AWE from Creative Labs Inc. on which two buffer memories ( 56 , 57 ) are added for a purpose to be explained below.
Likewise the control circuit of the display means includes two buffer memories ( 66 , 67 ) for a purpose to be explained below.
A thermally controlled 240 watt ventilated power supply provides power to the system. This power supply is protected against surges and harmonics.
The audiovisual reproduction system manages via its input controller circuit ( 3 ) a 14 inch (35.56 cm) touch screen “Intelli Touch” ( 33 ) from Elo Touch Systems Inc. which includes a glass coated board using “advanced surface wave technology” and an AT type bus controller. This touch screen allows, after having displayed on video monitor ( 62 ) or television screen ( 61 ) various selection data used by the customers, management command and control information used by the system manager or owner. It is likewise used for maintenance purposes in combination with external keyboard ( 34 ) which can be connected to the system which has a keyboard connector for this purpose, controlled by a key lock ( 32 ) via interface circuit ( 3 ).
Input circuit ( 3 ) likewise interfaces with the system a remote control set ( 31 ) composed for example of:
an infrared remote control from Mind Path Technologies Inc., an emitter which has 15 control keys for the microprocessor system and 8 control keys for the projection device. an infrared receiver with serial adapter from Mind Path Technologies Inc.
A fee payment device ( 35 ) from National Rejectors Inc. is likewise connected to input interface circuit ( 3 ). It is also possible to use any other device which allows receipt of any type of payment by coins, bills, tokens, magnetic chip cards or a combination of means of payment.
To house the system a chassis or frame of steel with external customizable fittings is also provided.
Besides these components, wireless microphone ( 55 ) is connected to audio controller ( 5 ); this allows transformation of the latter into a powerful public address system or possibly a karaoke machine. Likewise a wireless loudspeaker system can be used by the system.
Remote control set ( 31 ) allows the manager, for example from behind the bar, access to and control of various commands such as:
microphone start/stop command, loudspeaker muting command, audio volume control command; command to cancel the musical selection being played.
The system operating software has been developed around a library of tools and services largely oriented to the audiovisual domain in a multimedia environment. This library advantageously includes an efficient multitask operating system which efficiently authorizes simultaneous execution of multiple fragments of code. This operating software thus allows concurrent execution, in an orderly manner and avoiding any conflict, of operations performed on the display means, audio reproduction means as well as management of the telecommunications lines via the distribution network. In addition, the software has high flexibility.
The digitized and compressed audiovisual data are stored in storage means ( 21 ).
Each selection is available according to two digitized formats: hi-fi and CD quality.
Prior to describing and reading this organization chart in FIG. 2 , it must be noted that while all these modules described separately seem to be used sequentially, in reality the specific tasks of these modules are executed simultaneously in an environment using the multitask operating system. Consequently the organizational chart indicates the specific operations which the module must perform and not a branch toward this module which would invalidate all the operations performed by the other modules.
The first module, labeled SSM, is the system startup module. This module does only one thing, consequently it is loaded automatically when the system is powered up. If the system is started with a correct registration number it then directly enters the “in service” mode of the module labeled RRM.
The REG module is the registration mode module which, when it is activated for the first time or when approval for a new registration is necessary, indicates its software serial number and requests that the user enter his coordinates, such as the name of the establishment, address and telephone number.
The RMM module is the module of the “in service” mode which is the mode of operation which the system enters when its registration number has been validated. In this mode the system is ready to handle any request which can be triggered by various predefined events such as:
customers touching the screen: when a customer or user touches the screen, the system transfers control of the foreground session to the customer browsing and selection mode CBSM module, telecommunications network server call requests: when the system detects a loop on the phone line, it emits an asynchronous background procedure: the telecommunications services mode TSM module, requests concerning key switch ( 32 ): when the manager turns the key switch the system hands over control of its foreground session to the management mode SMM module, reception of a remote control signal: when a command is received, it is processed in a background session by the system command 5MM module while the foreground session remains available for other interventions, appearance of end of timing, showing inactivity of the system: when one of the various timers is activated, control is temporarily handed over to the inactivity routines IPM module for processing.
The system remains in the “in service” mode until one of the above described events takes place.
The IRM module is the inactivity routines module. It contains the routines which perform predetermined functions such as album cover display, broadcast of parts of musical pieces present in the system, reproduction of complete selections for internal promotional proposes, audio reproductions for external promotional purposes, spoken promotional announcements of new musical selections, withdrawal to an auxiliary source which can be called when the system is inactive and when a predefined but adjustable time interval corresponding to a timer has expired.
The SMM module is the system commands module. This module allows execution of functions which command the system to accept a required input by an infrared remote control device, these functions being handled instantaneously without the process underway being stopped. A very large number of these functions are possible, only some are listed below, in a nonrestrictive manner:
audio volume control of the played selections, audio volume control of the auxiliary played source, microphone start/stop command, microphone audio volume control, balance control, left channel, right channel, control of base frequency level, control of treble frequency level, command to cancel or skip a musical selection, panoramic effects command, zoom forward, zoom back, triggering of reset of the software program.
The MMM module is the management mode module. This module is triggered when the key switch is turned by the manager. The display of an ordinary screen is replaced by a display specific to system management. With this new display the manager can control all the settings which are possible with remote control. He can likewise take control of additional low level commands allowing for example definition of commands to be validated or invalidated on the remote control. He is also able to define a maximum of high and low levels for each system output source, these limits defining the range available on the remote control. Using this screen the manager can access the mode of new selection acquisitions by touching a button located on the touch screen. When the manager has succeeded in defining these commands as well as the system configuration, it is then enough to remove the key and the system returns automatically to the “in service” mode.
The NSAM module is the new selections acquisition mode module.
The CBSM module is the customer browsing and selection mode module. Access to this module is triggered from the “in service” when the customer touches the screen. The display allows the user to view a menu provided for powerful browsing assisted by digitized voice messages to guide the user in his choice of musical selections.
The TSM module is the telecommunications services mode module between the central server and the audiovisual reproduction system. This module allows management of all management services available on the distribution network. All the tasks specific to telecommunications are managed like the background tasks of the system. These tasks always use only the processing time remaining once the system has completed all its foreground tasks. Thus, when the system is busy with one of its higher priority tasks, the telecommunications tasks automatically will try to reduce the limitations on system resources and recover all the microprocessor processing time left available.
The SSC module is the system security control module. This module manages security, each system is linked to a local controller system according to a preestablished time pattern for acquisition of the approval signal in the form of the registration number authorizing it to operate. In addition, if cheating has been detected or the system cannot communicate via the network, said system automatically stops working.
The SPMM module allows management of musical selections, songs or video queued by the system for execution in the order of selection.
Finally, the SMM module allows remote management of system settings by the manager by remote control.
The multitask operating system comprises the essential component for allowing simultaneous execution of multiple code fragments and for managing priorities between the various tasks which arise.
This multitask operating system is organized as shown in FIG. 3 around a kernel comprising module ( 11 ) for resolving priorities between tasks, task supervisory module ( 12 ), module ( 13 ) for serialization of the hardware used, and process communications module ( 14 ). Each of the modules communicates with application programming interfaces ( 15 ) and database ( 16 ). There are as many programming interfaces as there are applications. Thus, module ( 15 ) includes first programming interface ( 151 ) for key switch ( 32 ), second programming interface ( 152 ) for remote control ( 31 ), third programming interface ( 153 ) for touch screen ( 33 ), fourth programming interface ( 154 ) for keyboard ( 34 ), fifth programming interface ( 155 ) for payment device ( 35 ), sixth programming interface ( 156 ) for audio control circuit ( 5 ), seventh programming interface ( 157 ) for video control circuit ( 6 ), and last interface ( 158 ) for telecommunications control circuit ( 4 ).
Five tasks with a decreasing order of priority are managed by the kernel of the operating system, the first ( 76 ) for the video inputs/outputs has the highest priority, the second ( 75 ) of level two relates to audio, the third ( 74 ) of level three to telecommunications, the fourth ( 73 ) of level four to interfaces and the fifth ( 70 ) of level five to management. These orders of priority will be considered by priority resolution module ( 11 ) as and when a task appears and disappears. Thus, as soon as a video task appears, the other tasks underway are suspended, priority is given to this task and all the system resources are assigned to the video task. At the output, video task ( 76 ) is designed to unload the video files of the mass memory ( 21 ) alternately to one of two buffers ( 66 , 67 ), while other buffer ( 67 or 66 ) is used by video controller circuit ( 6 ) to produce the display after data decompression. At the input, video task ( 76 ) is designed to transfer data received in telecommunications buffer ( 46 ) to mass storage ( 21 ). It is the same for audio task ( 75 ) on the one hand at the input between telecommunications buffer ( 46 ), and buffer ( 26 ) of mass memory ( 21 ), and on the other hand at the output between buffer ( 26 ) of mass memory ( 21 ) and one of two buffers ( 56 , 57 ) of audio controller circuit ( 5 ).
The task scheduler module will now be described in conjunction with FIG. 4 . In the order of priority this module performs first test ( 761 ) to determine if the video task is active. In the case of a negative response it passes to the following test which is second test ( 751 ) to determine if the audio task is still active. In the case of a negative response third test ( 741 ) determines if the communications task is active. After a positive response to one of the tests, at stage ( 131 ) it fills memory access request queue ( 13 ) and at stage ( 132 ) executes this storage request by reading or writing in the mass storage, then loops back to the first test. When the test on communications activity is affirmative, scheduler ( 12 ) performs a test to determine if it is a matter of reading or writing data in the memory. If yes, the read or write request is placed in a queue at stage ( 131 ). In the opposite case, the scheduler determines at stage ( 743 ) if it is transmission or reception and in the case of transmission sends by stage ( 744 ) a block of data to the central server. In the case of reception the scheduler verifies that the kernel buffers are free for access and in the affirmative sends a message to the central server to accept reception of a data block at stage ( 747 ). After receiving a block, error control ( 748 ) of the cyclic redundancy check type (CRC) is executed and the block is rejected at stage ( 740 ) in case of error, or accepted in the opposite case at stage ( 749 ) by sending a corresponding message to the central server indicating that the block bearing a specific number is rejected or accepted, then loops back to the start tests. When there is no higher level task active, at stage ( 731 or 701 ) the scheduler processes interface or management tasks.
Detection of an active task or ready task is done as shown in FIG. 5 by a test 721 to 761 respectively on each of the respective hardware or software buffers ( 26 ) of the hard disk, ( 36 ) of the interface, ( 46 ) of telecommunications, ( 56 and 57 ) of audio, ( 66 and 67 ) of video which are linked to each of respective controller circuits ( 2 , 3 , 4 , 5 , 6 ) of each of the hardware devices linked to central unit ( 1 ). Test ( 721 ) makes it possible to check if the data are present in the buffer of the disk input and output memory, test ( 731 ) makes it possible to check if the data are present in the buffers of the hardware or software memory buffers of the customer interface device, test ( 741 ) makes it possible to check if the data are present in the buffers of the hardware or software memory of the telecommunications device, test ( 751 ) makes it possible to check if the data are present in the buffer of the hardware or software memory for the direction, test ( 761 ) makes it possible to check if the data are present in the hardware or software memory buffers of the video device. If one or more of these buffers are filled with data, scheduler ( 12 ) positions the respective status buffer or buffers ( 821 ) for the hard disk, ( 831 ) for the interface, ( 841 ) for telecommunications, ( 851 ) for audio, ( 861 ) for video corresponding to the hardware at a logic state illustrative of the activity. In the opposite case the scheduler status buffers are returned at stage ( 800 ) to a value illustrative of inactivity.
Due, on the one hand, to the task management mode assigning highest priority to the video task, on the other hand, the presence of hardware or software buffers assigned to each of the tasks for temporary storage of data and the presence of status buffers relative to each task, it has been possible to have all these tasks managed by a single central unit with a multitask operating system which allows video display, i.e., moving images compared to a graphic representation in which the data to be processed are less complex. This use of video display can likewise be done without adversely affecting audio processing by the fact that audio controller circuit ( 5 ) includes buffers large enough to store a quantity of compressed data sufficient to allow transfer of video data to one of video buffers ( 66 , 67 ) during audio processing while waiting for the following transfer of audio data.
Moreover, the multitask operating system which includes a library containing a set of tools and services greatly facilitates operation by virtue of its integration in the storage means and the resulting high flexibility. In particular, for this reason it is possible to create a multimedia environment by simply and efficiently managing audio reproduction, video or graphics display and video animation. In addition, since the audiovisual data are digitized and stored in the storage means, much less space is used than for a traditional audiovisual reproduction system and consequently the congestion of the system according to the invention is clearly less.
Database ( 16 ) is composed, as shown in FIG. 6 , of several bases: first ( 161 ) with the titles of the audiovisual pieces, second ( 162 ) with the artists, third ( 163 ) with the labels, fourth ( 164 ) with albums, fifth ( 165 ) with royalties. First base ( 161 ) contains first item ( 1611 ) giving the title of the piece, second item ( 1612 ) giving the identification of the product, this identification being unique. Third item ( 1613 ) makes it possible to recognize the category, i.e., jazz, classical, popular, etc. Fourth item ( 1614 ) indicates the date of updating. Fifth item ( 1615 ) indicates the length in seconds for playing the piece.
Sixth item ( 1616 ) is a link to the royalties base. Seventh item ( 1617 ) is a link to the album. Eighth item ( 1618 ) is a link to the labels. Ninth item ( 1619 ) gives the purchase price for the jukebox manager;
Tenth item ( 1620 ) gives the cost of royalties for each performance of the piece;
Eleventh item ( 1610 ) is a link to the artist database, This link is composed of the identity of the artist. The artist database includes, besides the identity of the artist composed of item ( 1621 ), second item ( 1622 ) composed of the name of the artist or name of the group. The label database includes first item ( 1631 ) composed of the identity of the label, establishing the link to eighth item ( 1618 ) of the title database and second item ( 1632 ) composed of the name of the label. The album database contains first item which is the identity of the album ( 1641 ) which constitutes the link to seventh item ( 1617 ) of the title base. Second item ( 1642 ) comprises the title, third item ( 1643 ) is composed of the date of updating of the album, and fourth item ( 1644 ) composed of the label identity. The royalty base is composed of first item ( 1651 ) giving the identity of the royalty and corresponds to sixth item ( 1616 ) of the title base. Second item ( 1652 ) comprises the name of the individual receiving the royalties. Third item ( 1653 ) is composed of the destination address of the royalties. Fourth item ( 1654 ) is composed of the telephone and fifth item ( 1655 ) is composed of the number of a possible fax.
It is apparent that this database ( 16 ) thus makes it possible for the manager to keep up to date on costs, purchases of songs and royalties to be paid to each of the artists or groups of artists performing the songs or videos, this provided that a communications protocol allows loading of the songs and modification of the content of the database depending on the songs loaded and allows communications with the central server by uploading or downloading the corresponding information. This communication protocol is composed of a first stage during which the center requests communication with the unit to which the communication is addressed. The unit decodes the heading sent by the center and if it recognizes it, indicates to the center if it is available or not depending on the state of its system status determined as explained above. If it is not available the center will then send a new request. If it is available, the center begins to send a first data block and the following blocks in succession. Each of the blocks is composed of a plurality of fields as shown in FIG. 7 . First field ( 810 ) indicates the identification number of the seller; this allows multiple sellers to share a single communications link with the central site. Second field ( 811 ) indicates the application identity and makes it possible to distinguish between a digital song, a digital motion video, a stationary video or an stationary digital graphical image, allows updating of software, transmission of statistics, billing, updating of the database, transmission of surveys. Third field ( 812 ) makes it possible to identify a subtype of application such as the identity number of the product, type of billing, indication of a song in the MIDI standard or a digital song, or finally indication of whether it is the last block of a transmission. The following field ( 813 ) makes it possible to recognize the number of the block assigned sequentially to the block in this transmission. Fourth field ( 814 ) makes it possible to recognize the octet length of each transmission block. Fifth field ( 815 ) makes it possible to recognize variable length data of the transmission and sixth field ( 816 ) contains cyclic redundancy verification information which allows the jukebox to verify that there has not been any error in transmission by recomputing the values of this information from the received data. The data are coded with the identification number of the receiving station, i.e., the number of the jukebox; this prevents another station from receiving this information without having to pay royalties. This is another advantage of the invention because in the processes of the prior art it is not exactly known which stations have received messages and at the outside a cheat could indicate that the information has not been correctly received to avoid having to pay the royalties. Here this operation is impossible since the cheat does not have access to his identification number known solely by the computer and encoding done using this secret identification number makes it possible to prevent cheating and reception by other units not authorized to receive the information. Finally it can be understood that this protocol, by the information which the blocks contain, allows high flexibility of use, especially for transmitting video images or digitized songs, or again to allow updating of software as explained below according to the process in FIG. 8 . In the case of software updating, the central system sends at stage ( 821 ) a first start signal allowing the jukebox for which it is intended to be recognized by its identification number and to indicate to this jukebox the number of the software version. At this stage ( 821 ) the jukebox then performs an initial verification to ensure that the version number is higher than the number of the versions installed and then initiates the process of verification of the system status indicated by stage ( 801 ). This verification process has already been described with reference to FIG. 7 . In the case in which at stage ( 822 ) there is no system activity, at stage ( 823 ) the jukebox initiates display of a waiting message on the display device to prevent a user from interrupting the communication, and during this time receives the data composed of the new software to be installed. At stage ( 824 ) the unit backs up the current version and at stage ( 825 ) the unit modifies the startup file for startup with the backup version. After having completed this modification the unit at stage ( 826 ) applies the software received to the system software and restarts the system software at stage ( 827 ). After having restarted the system, the unit reverifies status ( 801 ) and at stage ( 828 ) determines if the system statuses are valid or not. In the case in which no errors are detected, at stage ( 829 ) the unit updates the startup files with the newly received version and returns to a waiting state. If an error is detected, the unit reinitializes the system at stage ( 830 ). Once installation is completed, the unit awaits occurrence of an event representative of a task in order to handle its tasks as illustrated above.
Due to the flexibility of the multitask system and its communications protocol, each unit of the jukebox can thus be selected independently of the units connected to the network and can update the databases or the version of the desired song or again the software version without disrupting the operation of the other units of the network and without having to wait specifically for all the units of a network to be available. This is independent of the modems used which can be of the high speed type for a standard telephone line or a specialized modem on a dedicated data link or a SDN modem for fiber optic transmission or again an IRD modem for satellite connection.
If one or more packets are not received correctly by the jukebox during transmission, it does not interrupt transmission since other jukeboxes can also be in communication. However when communication is stopped by the central server, each jukebox which has had a incident takes a line and signals the numbers of the packets not received to the center. This allows the center to resend them. If registration of one or more songs or videos or part of a song or video has not be done due to lack of enough space on the disk or storage means, the system of each jukebox signals to the manager by a display or audio message the packet number if it is part of a song or a video, or the numbers of the song or video which have not be registered for lack of space. This allows the manager, after having decided to erase certain songs or videos from the hard disk, to again request that the center send these songs or videos or the part not received.
Any modification by one skilled in the art is likewise part of the invention. Thus, regarding buffers, it should be remembered that they can be present either physically in the circuit to which they are assigned or implemented by software by reserving storage space in the system memory.
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Method for communication between a central server and a computerized juke-box which operates in a conference mode, including: sending a header before any transaction, which includes the identity of the destination together, the identity of the emitter, and the size of the packets; responding from the server in the form of a data packet, each packet sent by the server being encoded using the identification code of the juke-box software; and receiving a data packet by the juke-box, which decodes the packet, simultaneously performs a check on the data received by the CRC method and sends an acknowledgement of receipt to the server indicating the accuracy of the information received, to allow it to prepare and send another packet to the juke-box.
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CROSS REFERENCE TO RELATED APPLICATIONS
The present application claims the benefit under 35 USC 119 (e), of U.S. Provisional Application No. 60/149,459, filed Aug. 19, 1999.
BACKGROUND OF THE INVENTION
1. Field of Invention
The present invention relates to an interferometric detection system and method that can be used, for example, for detection of refractive index changes in picoliter sized samples for chip-scale analyses. The detection system has numerous applications, including universal/RI detection for CE (capillary electrophoresis), CEC (capillary electrochromatography) and FIA, physiometry, cell sorting/detection by scatter, ultra micro calorimetry, flow rate sensing and temperature sensing.
2. Description of the Prior Art
Capillary-based analysis schemes, biochemical analysis, basic research in the biological sciences such as localized pH determinations in tissues and studies in protein folding, detection and study of microorganisms, and the miniaturization of instrumentation down to the size of a chip all require small volume detection. In fact miniaturization of fluid handling systems is at the heart of the genomics and proteomics technology effort. These systems allow one to manipulate single cells or even single macromolecules and it has been recently shown that when liquid handling systems are shrunk to the micron and sub-micron range, small Reynolds numbers and mixing nanoliters in microseconds are possible. Yet, detecting the absolute temperature changes produced in a nanoliter volume T-jump experiment has not been possible. Additionally, the ability to measure biological events such as cold denaturation and binding constants at low temperatures is critically important, but currently limited by existing instrumentation. The potential to perform cellular level investigations and to do high throughput analysis can potentially be realized by using a new generation of analytical instruments based on “chips”, known as miniaturized total analysis systems (μ-TAS). In fact, commercial “laboratory on a chip” devices are now available. It has long been known that the volumetric constraints imposed on the detection system used in μ-TAS will dictate the utility of these techniques that are based on microfabrication. Typical injection volumes for μ-TAS are in the nanoliter (10 −9 L) to picoliter (10 −12 L) range and ultimately impart severe constraints on the detection system. In short, the detection volume must be comparable to the injection volume while not sacrificing sensitivity. Yet, the development of μ-TAS systems has been accompanied by the implementation, and to a much lesser extent, the improvement of “conventional” detection systems.
Most approaches for μ-TAS or on-chip detection have been based on “conventional” optical measurements, primarily absorption, fluorescence or electrochemical. Unfortunately, absorbance measurements are limited in chip-scale techniques because of their inherent path length sensitivity and solute absorbtivity. The fact that the channel dimensions are normally 10-20 μm deep and 20-50 μm wide further exacerbates the S/N limitation for absorbance determinations ultimately limiting picoliter volume detection limits to the range of 0.1-0.01 mM.
With the advent of lasers, light sources possessing unique properties including high spatial coherence, monochromaticity and high photon flux, unparalleled sensitivity and selectivity in chemical analysis is possible. The advantages of using lasers in micro-chemical analysis are well known and have been demonstrated thoroughly. Over the past five years, technical advances in the laser have lead to reduced cost, enhanced reliability and availability of new wavelengths or multi-wavelength scanning systems. The result has been the demonstration of a number of high sensitivity/micro-volume detection methodologies for universal analysis. For example laser-induced fluorescence (LIF) can provide extremely low detection limits, with most laboratories able to detect as few as 10 5 molecules. In fact, recent developments in ultra-high sensitivity LIF have allowed single molecule detection to be performed ‘on-chip’. While fluorescence is an inherently sensitive detection method, it can be expensive to implement and is only applicable to solutes that are either, naturally fluorescent (the number of such molecules is actually quite small) or that can be chemically modified to fluoresce. Other approaches to on-chip detection have primarily included thermal conductivity, electroluminescence and electrochemical methods. However, these technologies are also expensive and hard to implement.
Refractive index detection is still a common technique used in chemical and biochemical analysis that has been successfully applied to several small volume analytical separation schemes. For various reasons, RI detection represents an attractive alternative to fluorescence and absorbance. First, RI detection is relatively simple. Second, it can be used with a wide range of buffer systems. Finally, RI detection is universal, theoretically allowing detection of any solute, making it particularly applicable to solutes with poor absorption or fluorescence properties. However, for a number of reasons, attempts toward implementation of RI detection in chip-scale analyses has been somewhat problematic.
Previous attempts for on-chip RI detection have generally involved the use of either waveguiding or interferometry. Among these techniques are the Mach-Zender approach, the porous silicon-based optical interferometer, surface plasmon resonance (SPR) (and related) techniques, the ‘on-chip’ spiral-shaped waveguide refractometer, and the holographic forward scatter interferometer. While each of the aforementioned RI measurement techniques can produce impressive results, they are all limited when applied to on-chip detection with chip scale analyses. In general, the path length dependency of evanescent wave-based techniques like SPR or the Mach Zender interferometer, demands a long sensing region be in contact with the separation fluid resulting in an optical “detection” volume too large to be compatible with chip-scale analyses.
The porous silicon-based optical interferometer (a Fabry-Perot system) can provide pico- and even femtomolar analyte sensitivity, but for the RI signal to be produced, this sensor requires (as do the SPR sensors) that the exogenous ‘reporter’ molecules be attached to the surface of the silicon and subsequently bind to the desired or target solute. This methodology of using molecular recognition which leads to an RI change can be used as an on-chip detector, provides solute selectively, leading inherently to high sensitivity, but is limited by reaction kinetics and the need to do sophisticated biochemistry and surface immobilization. These chemistries are normally diffusion limited and thus take time. In addition, solute events produced in CE, FIA or chip scale HPLC must be detected as they traverse the detector. Temporal constraints can be severe and range from 10's of milli-seconds to several minutes. Thus the peak must be sensed or analyzed in the probe volume during the elution time. Furthermore, technologies such as SPR do not provide the option to directly monitor μ-Vol. temperature changes as are needed to study, for example, reaction kinetics or to perform on-chip flow rate sensing.
The holographic forward scatter interferometer is thus far, the most promising approach for on-chip universal or RI detection in CE, and uses a holographic grating and a forward scattering optical configuration. However, while research on this technique has clearly shown the potential for doing on-chip RI sensing, the sensitivity of the forward scatter technique employed is inherently limited because it is has a single pass optical configuration, e.g. the probe beam traverses only once through the detection channel.
In view of the foregoing, a need still remains for an RI detection technique that is sensitive, universal can probe ultra-small volumes, is compatible with the chip-based format and can be employed for temperature and flow rate sensing of ultra-small volumes.
SUMMARY OF THE INVENTION
The present invention fulfills the need for a new sensing methodology applicable to μ-TAS through provision of an interferometric detection system and method that circumvent the drawbacks of ‘standard’ interferometric methods and the limitations of the forward scatter technique. The system includes a source of coherent light, such as a diode or He—Ne laser, a channel of capillary dimensions that is preferably etched in a substrate for reception of a sample to be analyzed, and a photodetector for detecting backscattered light from the sample at a detection zone.
The laser source generates an easy to align simple optical train comprised of an unfocused laser beam that is incident on the etched channel for generating the backscattered light. The backscattered light comprises interference fringe patterns that result from the reflective and refractive interaction of the incident laser beam with the channel walls and the sample. These fringe patterns include a plurality of light bands whose positions shift as the refractive index of the sample is varied, either through compositional changes or through temperature changes, for example. The photodetector detects the backscattered light and converts it into intensity signals that vary as the positions of the light bands in the fringe patterns shift, and can thus be employed to determine the refractive index (RI), or an RI related characteristic property, of the sample. A signal analyzer, such as a computer or an electrical circuit, is employed for this purpose to analyze the photodetector signals, and determine the characteristic property of the sample.
Preferably, the channel has a generally hemispherical cross sectional shape. A unique multi-pass optical configuration is inherently created by the channel characteristics, and is based on the interaction of the unfocused laser beam and the curved surface of the channel, that allows interferometric measurements in small volumes at high sensitivity. Additionally, if a laser diode is employed as the source, not only does this enable use of wavelength modulation for significant improvements in signal-to-noise ratio, but it also makes it possible to integrate the entire detector device directly onto a single microchip.
The detector can be employed for any application that requires interferometric measurements, however, the detector is particularly attractive for making universal solute quantification, temperature and flow rate measurements. In these applications, the detector provides ultra-high sensitivity due to the multi-pass optical configuration of the channel. In the temperature measuring embodiment, the signal analyzer receives the signals generated by the photodetector and analyzes them using the principle that the refractive index of the sample varies proportionally to its temperature. In this manner, the signal analyzer can calculate temperature changes in the sample from positional shifts in the detected interference fringe patterns.
In the flow measuring embodiment, the same principle is also employed by the signal analyzer to identify a point in time at which a thermal perturbation is detected in a flow stream in the channel. First, a flow stream whose flow rate is to be determined, is locally heated at a point that is known distance along the channel from the detection zone. The signal analyzer for this embodiment includes a timing means or circuit that notes the time at which the flow stream heating occurs. Then, the signal analyzer determines from the positional shifts of the light bands in the interference fringe patterns, the time at which the thermal perturbation in the flow stream arrives at the detection zone. The signal analyzer then determines the flow rate from the time interval and distance values.
BRIEF DESCRIPTION OF THE DRAWINGS
The features and advantages of the present invention will become apparent from the following detailed description of a number of preferred embodiments thereof, taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a schematic block diagram of an interferometric detection system that is constructed in accordance with a first preferred embodiment of the present invention;
FIG. 2 is a diagrammatic illustration of a silica or other material chip having a channel therein that forms a part of the system of FIG. 1, and is employed for receiving a sample whose refractive index or refractive index related characteristic properties are to be determined;
FIGS. 3A and 3B are sectional views of the chip of FIG. 2 showing the shape of the channel, with FIG. 3A being taken along line 1 — 1 of FIG. 2, and FIG. 3B being taken along line 2 — 2 of FIG. 2;
FIG. 4 is an illustration of an interference fringe pattern that is produced by the system of FIG. 1;
FIG. 5 is a schematic illustration of a second preferred embodiment of the present invention that is employed for measuring the flow rate of a flow stream;
FIG. 6 is a schematic illustration of the interaction of an incident laser beam on the curved channel of the system of FIG. 1; and
FIG. 7 is a schematic block diagram of another embodiment of the invention in which all of the system elements are formed on a single microchip.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference now to a first preferred embodiment of the present invention, an interferometric detection system 10 is illustrated in FIG. 1 which makes use of a technique that employs backscattered light to determine the RI or RI related characteristic properties of a sample. The backscatter detection technique is generally disclosed in U.S. Pat. No. 5,325,170 to Bornhop, which is hereby incorporated by reference. However, in the present invention where backscatter detection is used for “on-chip” detection with ultra-small sample volumes, the technique employed is referred to as Micro-Interferometric Backscatter Detection or MIBD.
The interferometric detection system 10 includes a laser or other source of coherent light 12 , which is preferably a low power (3-15 mW) laser (He/Ne or Diode), and generates a laser beam 14 . As with any interferometric technique for micro-chemical analysis, MIBD benefits from many of advantages lasers provide, including high spatial coherence, monochromaticity, and high photon flux. The intensity of the laser beam 14 can be reduced as needed with a series of optional neutral density filters 16 (e.g., optical density of 0.5, 1.0, 0.3 respectively). Upon reduction of the intensity, the beam 14 is directed to an optional mirror 18 that is angled at approximately 45° with respect to the plane of propagation of the laser beam 14 . The mirror 18 re-directs the beam 14 onto a substrate chip 20 having a channel 22 formed therein, preferably by etching, for reception of a sample volume to be analyzed. It will be understood that the mirror 18 can be deleted, and the laser 12 can be repositioned to aim the laser beam 14 directly at the etched channel 22 if desired.
The chip 20 is preferably formed of silica, but can be any other suitable optically reflective material, such as plastic. The only requirement is that the material from which the chip 20 is made, must have a different index of refraction than that of a sample volume to be tested. In the exemplary embodiment of FIG. 1, the chip 20 is shown mounted on a peltier temperature controlled A 1 support block 23 , which in turn is affixed to an X-Y translation stage 24 that allows adjustment of the chip 20 relative to the laser beam 14 . More particularly, the chip 20 is preferably tilted slightly (e.g., approximately 7°) so that the (nearly direct) backscattered light from the channel 22 can be directed onto a photodetector 25 . The purpose of the temperature controlled support block 23 is to insure that the sample in the channel 22 is maintained at a constant temperature since the RI of a sample is known to vary linearly with its temperature. Alternatively, this characteristic also allows the detection system 10 to be utilized for making very accurate temperature measurements.
The photodetector 25 can be one of any number of image sensing devices, including a bi-cell position sensor, a CCD camera and laser beam analyzer (such as an LBA 100A, Spiricon, Inc. UT) assembly, a slit-photodetector assembly, an avalanche photodiode, or any other suitable photodetection device. The backscattered light comprises interference fringe patterns that result from the reflective and refractive interaction of the incident laser beam 14 with the walls of the channel 22 and the sample. These fringe patterns include a plurality of light bands (see FIG. 4) whose positions shift as the refractive index of the sample is varied, either through compositional changes or through temperature changes, for example. The photodetector 25 detects the backscattered light and converts it into one or more intensity signals that vary as the positions of the light bands in the fringe patterns shift. For fringe profiling, the photodetector 25 is preferably mounted above the chip 20 at an approximately 45° angle thereto.
The intensity signals from the photodetector 25 are fed into a signal analyzer 28 for fringe pattern analysis, and determination therefrom of the RI or an RI related characteristic property of a sample in the channel 22 . The signal analyzer 28 can be a computer (e.g., a PC) or a dedicated electrical circuit, for example. Preferably, the signal analyzer 28 includes the programming or circuitry necessary to determine from the intensity signals, the RI or other characteristic properties of the sample to be determined, such as temperature or flow rate, for example.
FIG. 2 shows a top view of the chip 20 showing the channel 22 . An injection port 30 and an exit port 32 are laser drilled at opposite ends of the channel 22 to allow for introduction and removal of a fluid sample to be analyzed. The laser beam 14 is directed to impinge upon the channel 22 at a point 34 that is a short distance (e.g., about 2 mm) from the exit port 32 and is graphically shown by the circle, labeled “detection zone”, in FIG. 2 .
As illustrated in FIGS. 3A and 3B, the chip 20 preferably consists of first and second substrate pieces 36 and 38 that are fused together, with the channel 22 being formed in the first, top substrate piece 36 , and having a generally hemispherical cross-sectional shape. The hemisphere has a radius R of between 5 and 150 microns, and most preferably between 10 and 50 microns. Although it is prefererred that the channel 22 be truly hemispherical in shape, to accommodate conventional etching techniques, the channel 22 is formed by first etching a first 90 degree arc 40 in the top substrate piece 36 , and then etching a second 90 degree arc 42 . This etching process inherently results in the formation of a short, flat portion or segment 44 between the first and second arcs 40 and 42 . The length L of the flat portion 44 should be as short as possible, preferably 5-25 microns. Surprisingly, as long as the length of the flat portion 44 does not exceed the length of the channel radius R, there is no adverse effect on the interference fringes that are generated by the channel 22 . The second, bottom substrate piece 38 forms a floor 45 of the channel 22 , and has a thickness T that is approximately one third to one times the radius R of the arcs 40 and 42 .
Interestingly, even though the channel 22 is of the general shape of a hemisphere or half circle, including the flat portion 44 , relatively high contrast interference fringes (much like those seen with full capillaries) have been observed in experiments on a prototype of the invention. The inherent characteristics of the channel 22 result in a multi pass optical configuration in which multi path reflections occur, and increase the sensitivity of the detector system 10 . A typical interference pattern produced by an unmodified chip filled with distilled/deionized water is shown in the false color intensity profile (black no photons and white is the intensity for detector saturation) shown in FIG. 4 . These observations are very exciting because, 1) the features (arcs 40 and 42 ) on the chip 20 that produce the interference fringes are quite common and easy to manufacture, 2) no additional optics are needed, and 3) the fringes have very high contrast allowing sensitive detection of optical pathlength changes. It is noteworthy that all of the measurements are obtained using a very simple optical train with no additional focusing or collection optics and using a chip that has no reflective coatings. In short, the chip-scale RI detector configuration uses unaltered chips.
Numerous experiments have been conducted to verify the operation of the on-chip detection system 10 , and determine which components provide the best sensitivity. A first experiment using varying concentrations of a glycerol solution was performed to evaluate the detection system 10 using the CCD camera and the laser beam analyzer for measuring fringe movement. The fringe movement varies linearly with concentration (change in RI) over 2 decades. The limit of detection calculated at 3σ was 31.47 mM of solute and was limited mainly by the LBA software.
In a second experiment, to improve the sensitivity of the on-chip RI measurement, the neutral density filters 16 were removed and a slit/photodetector assembly was used instead of the CCD camera/laser beam analyzer system. In this experiment, the slit/photodetector assembly was located on the order of 28 cm from the front surface of the chip 20 . The photodetector 25 consisted of a pin photodiode integrated with a 632.8 nm interference filter (Coherent-Ealing) wired with a simple current to voltage circuit. A 50-micron precision air slit (Melles Griot) was mounted vertically in the center of the active surface area of the photodiode. The voltage output from the photodiode was then amplified (Gain=100) by a low-noise preamplifier (Stanford Research Systems) using a 30 Hz low pass filter (12 dB/octave). The analog signal from the preamplifier was then digitized with an external DAQ board (PPIO-AIO8, CyberResearch, Branford, Conn.) and displayed on the PC computer 28 running a digital strip-chart recorder (Labtech for Windows).
The slit-photodetector assembly was aligned on the edge of a fringe in order to monitor fringe movement. The position of the assembly corresponds to the edge of the sloping intensity gradient of the working fringe and is located at I=1/e 2 of the intensity distribution. Since the intensity of a backscattered fringe is essentially Gaussian, a change in refractive index of the solution in the probe volume produces a change in the light intensity striking the active surface of the photodetector 25 . As the fringe shifts, a small voltage output from the photodetector 25 is observed, which is linearly proportional to a change in refractive index (Δn).
A calibration curve was generated with the slit/photodetector using the exact same procedure and glycerol solutions of the same concentrations as with the CCD/LBA configuration. The 3σ detection limit for the backscatter detector using a slit/photodetector assembly was found to be 18.33 mM, substantially better than the 31.47 mM limit achieved with the CCD/LBA experimental set up. The lower detection limits are achievable with a slit/photodetector assembly since small positional shifts of the backscattered fringes result in large intensity changes due to their pseudo-Gaussian intensity profile. The CCD/laser beam analyzer system measures only positional shifts, which are considerably less sensitive than the intensity changes seen by the slit/photodetector assembly.
In a third experiment, to improve the S/N of the measurement still further, the photodetector 25 was a small area avalanche photodiode (e.g., such as those available from Texas Optoelectronics, Inc.). The avalanche photodiode (APD) was operated near the breakdown voltage and driven with a reverse bias. The APD was aligned on the edge of the fringe as described for the slit/photodetector assembly, and fringe movement was denoted by changes in intensity. The signal from the APD was digitized with an external DAQ board (PPIO-AIO8, CyberResearch, Branford, Conn.) and displayed on the PC computer 28 running a digital stripchart recorder (Labtech for Windows).
Running tests on a series of glycerol solutions, revealed that the 3σ detection limit for glycerol is just 4.1 mM. By using the APD (even at a wavelength, 632.8 nm, where the device has poor quantum efficiency) a 4.4 fold S/N gain is realized.
Still further increases in sensitivity have been realized in subsequent experiments using a bi-cell position photodetector, and a diode laser with special optics to produce a pseudo-Gaussian beam of approximately 75 μm, at a distance of 50 cm and over a relatively long focal length. In this study the detection volume was 188 picoliters and a 2σ concentration detection limit for glycerol of 494 μM (139×10 −15 moles or 12.8 picograms of solute) was attained, without active thermal control. Thus, a reduction in the volume and an increase in sensitivity were realized as a consequence of several technical modifications to the system.
The detection limits achieved in the foregoing experiments represent the lowest RI detection limits that have been achieved to date with a system that is compatible with chip-scale sensing (low nanoliter detection volumes). For reference, MIBD is already an order of magnitude more sensitive than the holographic forward scatter technique.
A few important points should be made at this juncture. First, the detection limits were accomplished without any active thermal control of the chip (resulting in increased noise due to thermal perturbations in the dc mode (i.e. no wavelength modulation)) and using minimal active electronic filtering. In measurements of refractive index (n), the primary source of noise is thermal sensitivity. For most cases involving fluids, n has a relatively high thermal coefficient (dn/dT), requiring very precise temperature stabilization of the system. As an example, dn/dT for H 2 O is on the order of 8×10 −4 ° C., so at an analytically useful detection limit for Δn of one part in 10 6 , the temperature-induced signal corresponds to a change in T of 1×10 −2 ° C. Therefore, thermal stability of the system must be maintained at the millidegree centigrade label, to determine n to one part in 10 8 . This level of temperature control can be achieved using a thermostated flow cell with active control using a Peltier thermoelectric cooling chip (e.g., such as is available from Melcore, Trenton, N.J.) controlled by a power supply (e.g., ILX Lightwave, Bozeman, Mont.) wired in feedback from a calibrated thermocouple.
Conversely, as discussed previously, the thermal “noise” in RI measurements can be used to the advantage of the analyst. For example, thermal sensitivity can be used to determine minute temperature changes in small-volume following streams, non-invasive process stream monitoring, and even protein folding. The relationship between dn and dT is linear. Therefore, MIBD can be used to measure thermal changes at a microdegree centigrade level and to determine dn/dT for fluids.
To demonstrate use of the system 10 of FIG. 1 for detecting temperature changes, another experiment was conducted. In this experiment, thermometry was performed in a probe volume of just 3.14×10 −9 L as defined by the diameter of the laser beam 14 and the radius (in this case, 50 microns) of the etched channel 22 . Distilled/deionized water was hydrodynamically injected into the channel 22 and allowed to temperature and pressure stabilize. Next the temperature of the channel 22 was manually changed in approximately 0.3° C. increments, the sample was allowed to temperature stabilize, and a relative change in refractive index measurement was obtained. Upon graphing the results of relative change in RI versus temperature for water, a detection limit of 0.011° C. (11 millidegree C.) was determined based on the 3 sigma statistics. These results confirm that the signal analyzer 28 can be programmed to determine the temperature of the sample from an analysis of the fringe pattern signals with a high degree of sensitivity.
Another embodiment of the present invention is illustrated in FIG. 5 . This embodiment is designed for measuring the flow rate of a flow stream flowing through the channel 22 . The signal analyzer 28 in this embodiment contains timing circuitry or programming, and controls operation of a heating source 50 that provides localized heating of a point 52 along the channel 22 that is spaced a known distance x from the detection zone 34 . Preferably, the heating source is an infrared laser that can provide rapid localized heating of a sample flow stream in the channel 22 .
In the operation of this embodiment, the heating source 50 is triggered at a first instant in time to provide the localized heating of a portion of the flow stream. This creates a temperature perturbation in the flow stream that moves toward the detection zone 34 . The signal analyzer 28 then monitors the intensity signals generated by the photodetector 25 , and detects therefrom, the instant in time when the temperature perturbation arrives at the detection zone 34 . The time interval between when the flow stream was heated and when the temperature perturbation is detected is then employed with the value of x to determine the flow rate of the flow stream.
Using ASAP (an optical modeling program from Breault Research, Tuscon Ariz.) a few preliminary modeling experiments were performed to demonstrate the multi pass optical configuration provided by the channel 22 , and the path length insensitivity that results. In the first investigation illumination impinges onto the etched side of the chip 20 , so that the light impinges on the curved surface just after entering the substrate. FIG. 6 illustrates the results of this simulation, and clearly shows the multipath reflections that increase the system's sensitivity, or leads to an inherent insensitivity of performance on the size of the channel 22 . Put another way, the multi pass configuration eliminates optical path length constraints, thus allowing for smaller and smaller detection volumes. In FIG. 6, 9 initial rays are traced through a chip with an etched channel with a diameter of 100 μm. The laser source is located at some distance in +Z direction. Splits (the number of rays that will continue at interfaces) are set to 3. The middle plane simulates the lid that covers the channel. Since the index refraction on both sides of that plane is the same its presence does not affect the rays intersecting that plane. Since the rays that continue to travel in the −Z direction, after they passed through the chip, do not contribute to the formation of the backscattered fringe pattern they are ignored and dropped out of simulation.
It is certain that even lower detection limits for MIBD are possible. First, simply increasing the distance of the photodetector 25 from the front surface of the etched channel 22 will produce larger “apparent” fringe movement because angular displacement grows as the detector to channel distance increases. In general, this geometric relationship dictates sensitivity to angular displacement and indicates that every 2 fold increase in distance will produce at least a 2 fold sensitivity improvement. Second, lower detection limits will be achieved by using either a longer wavelength laser or an APD whose sensitivity is maximized at the wavelength of the laser used. For example, at the He/Ne wavelength of 632.8 nm, the radiant responsivity of the current detector is approximately 10 A/W, but at the wavelength of 700 nm, the radiant responsivity of the device increases by a factor of three to 30 A/W. As a result, detection limits are predicted to improve by at least 3-fold. Third and finally, the detection volume for MIBD on a chip can be further reduced by using a smaller diameter laser beam (e.g., lasers generating 10 μm diameter beams are available), or a fiber couple diode laser combined with a smaller radius channel.
A few observations should be made at this point concerning the type of laser employed in the detector system 10 . While HeNe lasers have excellent optical properties, they are limited in applications that demand miniaturization by their bulky size. As a result, VCSELs and diode lasers are replacing HeNe lasers in many industrial, medical, and analytical applications. VCSELs and diode lasers, in general, are solid state, low-cost compact, light sources that possess many of the properties of gas lasers (HeNe's). Among them are good beam quality (TEM 00 ), low divergence, and some polarization purity. Furthermore, they have characteristic long lifetimes (in excess of 50,000 hours), and provide reasonable coherent lengths (as great as 1 meter). VCSELs and diode lasers differ, however, from HeNe lasers in several important ways, particularly when using them as interferometry sources. First, wavelength stability of most VCSELs and diode lasers is generally poor due the device's structure (small cavity size), resulting in a dependency on and sensitivity to current and temperature changes. Second, while emitting light that is inherently linearly polarized, the polarity purity of a VCSEL's or diode laser's beam is relatively low (100:1). Nevertheless, if proper care is taken, VCSELs and diode lasers are low cost, coherent light sources that are adequate for interferometric detection schemes such as MIBD for both RI and polarimetric detection.
One of the most important advantages of VCSELs and diode lasers in the present application, is that they facilitate reduction in size of the RI detector system 10 to the point of being incorporated directly onto the chip 20 . FIG. 7 illustrates such an embodiment in which both the laser 12 and the photodetector 25 are formed integrally with the chip 20 .
Another advantage of using VCSELs or laser diodes in interferometry is that their optical output (wavelength) can be easily modulated through the supply current. Wavelength modulation opens a path to potential alternative detection schemes in on-chip RI detection using micro-interferometry as a method of decreasing the thermal sensitivity of the measurement and lowering the limit of detection of the technique. Thus, the system 10 can be configured so that detection is performed in the AC regime (source wavelength modulation).
When wavelength modulation techniques are used with VCSELs and diode lasers, it is possible to make exceeding sensitive optical absorbance measurements. In fact the sensitivity possible approaches the shot noise limit, i.e. 10 −7 AU in a 1 Hz bandwidth. Furthermore, with the advent of rapidly tunable (over a wide wavelength range), single mode, circular beam VCSELS, these devices are suitable sources for the on-chip interferometric detection technique. In short, by using such an approach for on-chip RI detection based on micro-interferometry, a significant (as much as 500 fold) improvement in S/N may be achievable for the instrument.
In conclusion, using on-chip RI detection based on micro-interferometry, the present invention performs interference detection in channels with ultra-small volumes and with a simple optical configuration that requires no additional optics. The on-chip RI detector is an effective universal detection system that expands the ability to sense or detect otherwise invisible solutes, particularly those important to proteomic analysis and high throughput screening. The detector's S/N ratio is not hindered by volume reduction, its probe volume and detection volume are the same, it is a non-invasive method, and is universal in nature. Thus, the detector can potentially play an important role in integrated genomics technology. It should also allow protein folding and biochemical bonding measurements previously not possible. Reaction kinetics can be followed in nanoliter volumes, and millidegree temperature changes can be quantified. Finally, the invention allows the further development of μ-TAS and other techniques for cellular level analysis.
Although the invention has been disclosed in terms of a number of preferred embodiments and variations thereon, it will be understood that numerous modifications and additional variations could be made thereto without departing from the scope of the invention as defined in the following claims.
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An optical detection scheme for on-chip, high sensitivity refractive index detection is based on micro-interferometry, and allows for picoliter detection volumes and universal analyte sensitivity. The invention employs three main elements: a source of coherent light, such as a VCSEL, laser diode or He—Ne laser; an etched channel of capillary dimensions in a substrate for reception of a sample to be analyzed; and a photodetector for detecting laser light reflected off of the channel. The laser source generates an unfocused laser beam that is incident on the etched channel. A unique multi-pass optical configuration is inherently created by the channel characteristics, and is based on the interaction of the unfocused laser beam and the curved surface of the channel, that allows RI measurements in small volumes at high sensitivity. The entire device, including the laser and the photodetector can be formed on a single microchip. The detector has numerous applications, including universal/RI detection for CE (capillary electrophoresis), CEC (capillary electrochromatography) and FIA, physiometry, cell sorting/detection by scatter, ultra micro calorimetry, flow rate sensing and temperature sensing.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a novel dichroic azo dyestuff used for a polarizing film and the polarizing film thereof.
[0003] 2. Description of the Related Art
[0004] The current polarizing films are grouped into Ioding Type and Dye Type.
[0005] Ioding Type Polarizing Film: the polarizing film constituted with PVA and iodine is the major part of the market. The major disadvantage of Ioding Type Polarizing Film is that the polarized efficiency is reduced within the elapsed time under high temperature and moisture. Although the utilization of boric acid, glyoxal, or heat treatment which can form polyethylene caused by the reduction of OH groups enhances the heat proof character, it is still not met the requirement of heat and moisture proof claimed in some situations.
[0006] A direct azo-dye is the major part of the dichroic dyestuff used for Dye Type Polarizing Film. It is the characteristic that the axial in the structure of the dye molecule is linear. Thereby, the dichroic property is presented due to the difference between the absorbance of the molecule with the parallel and perpendicular axial to light.
[0007] Dye Type Polarizing Film: a dye type polarizing film, with preferred heat proof, moisture proof and so on, is usually used for the outdoor type displays necessary for cars, airplanes and so on. However, the major disadvantage is the low polarized efficiency. The manufacturing method, through the stretching alignment of PVA and the dyes with identical absorbance and high-polarized efficiency in visible light, is the same as that of Ioding Type Polarizing Film. Generally, the direct dyes or acid dyes with azo groups are used. As compared with Ioding Type, Dye Type has preferred heat and moisture stability. In other words, it has preferred heat and moisture proof.
[0008] The present invention displays that the derivation from the core structure of the azoxy type polarizing film to establish side chains can provide high-polarized efficiency and climate proof. The purity of the easily afforded dyestuff by less synthetic steps is preferred, without complicated purification. The PVA type polarizing film of the dyestuff has preferred heat and moisture proof and its polarized efficiency is equal to that of Ioding Type Polarizing Film.
SUMMARY OF THE INVENTION
[0009] The present invention provides a dichroic azo dyestuff with heat proof and moisture proof characters. The present invention also provides a dye type polarizing film.
[0010] The dichroic azo dyestuff of the present invention, of which the structure of the free acid is the azo dyestuff compound of the following formula (I):
[0000]
[0000] wherein,
R 1 and R 3 each independently is —OH or —NH 2 ;
R 2 and R 4 each independently is —H, —OH, —NH 2 or —NHR 5 ;
R 5 is
[0011]
R 6 is —H or —CH 3 ;
[0012] n is 0, 1 or 2.
[0013] The azo dyestuff compound of formula (I) of the present invention, where, preferably, n is 1 or 2; R 1 is —OH; and R 3 is —NH 2 .
[0014] Examples of the azo dyestuff compound of formula (I) of the present invention includes the azo dyestuff compounds of the following formula (1) to (12):
[0000]
[0015] The dye type polarizing film of the present invention is made from polarizing film base material containing dichroic dyestuff, said dichroic dyestuff comprising the above-mentioned azo dyestuff compound of formula (I).
[0016] The dye type polarizing film of the present invention, wherein the polarizing film base material is preferable polyvinyl alcohol.
[0017] The dye type polarizing film of the present invention, wherein, the azo dyestuff compound comprised in the dichroic dyestuff can be any of the above-mentioned formulas (1) to (12).
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0018] The azo dyestuff compound of formula (I) of the present invention can be presented in forms of free acid or salt, such as alkaline metal salt and alkaline-earth metal salt in particular, and the alkaline metal salt is preferred in use.
[0019] The general synthesis equation of the azo dyestuff compound of formula (I) of the present invention is described as below:
1. Diazotization:
[0020]
2. Coupling Reaction
[0021]
3. Semi-reduction:
[0022]
[0023] The azo dyestuff compound of formula (I) of the present invention can be synthesized with the above steps.
[0024] The azo dyestuff compound of formula (I) of the present invention can be in forms of free acids or salts. Examples of salts include alkaline metal salts, such as lithium salt, sodium salt, sylvite; ammonium salt; organic ammonium salt, such as ethanolamine salt and alkylammonium. It is better to take sodium salt while using the compound in polarizing film.
[0025] The preparation of the dye type polarizing film of the present invention, according to conventional dyeing method, is to contain the polymer film as polarizing film base material with the dyestuff compound of formula (I). Besides, the dyestuffs can work with organic dyestuffs other then the compound of formula (I) to achieve customers' needs.
[0026] The polymer film of the polarizing film base material comprises materials made from polyvinyl alcohol resin, polyvinyl acetate resin, ethylene/vinylacetate (EVA) resin, nylon resin, and polyester resin.
[0027] For the adsorption performance and dyestuff directionality performance of the polarizing film base material, the film derived from polyvinyl alcohol compound (especially polyvinyl alcohol film) is preferred.
[0028] Generally, a conventional method of dyeing the polymer film is taken to prepare the polarizing film. The dyeing method, for example, can be carried out with the following steps. Firstly, dissolve dichromatic dyestuffs in water to obtain a dyeing solution. The concentration of the dyestuffs in the dyeing solution is not limited, but usually in the range of 0.0001-10% by weight. Besides, a dyeing auxiliary agent can be added if necessary. Take sodium sulfate for example, it is appropriate to add 1-10% by weight in the dyeing solution.
[0029] The polymer film is dyed by dipping into the above dyeing solution. The temperature of dyeing is preferable 40° C.-80° C. Stretching the polymer film to make the dichroic dyestuff have directionality. The stretching method can be any conventional methods, such as wet method and dry method, to let the polymer film have directionality before or after dyeing.
[0030] A post-treatment to the dichromatic dyestuff-contained and directional polymer film can be taken, if desired, such as treated with boric acid according to conventional methods. The purpose of such a post-treatment is to improve the transmission, light polarization and durability of the polarizing film. The adequate condition of boric acid treatment depends on the type of the polymer film. The concentration of boric acid in the boric acid solution is usually in the range of 1-15% by weight, preferably 5-10% by weight, and the temperature ranges from 30° C. to 80° C., preferably 50° C. to 80° C.
[0031] In addition, the retention process can be preformed by the solution including cationic polymers if necessary. The polarizing plate can be formed by making the protecting film of high light transmittance and mechanic strength adhere to the one or both surface of the polarizing film constituted with the dyestuff afforded through the above method. The material of the protecting film could be that in common use, including cellulose acetate films, acrylic acid films and fluoro resin films (for examples: perfluorinated ethvlence-propylene copolymers, polyester films, polyolefine cigarette films, polyamide films).
[0032] The color can be modified or the polarized efficiency can be improved by other organic dyes worked with the dichroic azo dyestuff of formula (I) used for the polarizing film. Herein, the organic dyes can be any dyes with the high dichroic character.
[0033] For convenience, the following embodiments are used for the further concrete description.
[0034] The following embodiments are the description of the present invention, and the claims of the present invention are not limited to these.
[0035] Unless otherwise stated, the “° C.” used in the examples refers to temperature, the parts of weight and volume are in “g” and “ml”, respectively.
EXAMPLE 1
[0036] Preparing the azo-dyestuff compound of formula (1):
[0000]
[0037] The above azo-dyestuff compound of formula (1) can be obtained, according to the following three steps:
1. DiDiazotization:
[0038]
[0039] 40 parts of 4-amino-4′-nitrostilbene-2,2′-disulfonic acid (A) was dissolved in 300 parts of water and 30 parts of 32% hydrochloride acid was added, followed by stirring at 0-5° C. Diazotization was realized with the addition of 8 parts of sodium nitrite at the same temperature range.
2. Coupling Reaction:
[0040]
[0041] 35.12 parts of 2-amino-5-hydroxynaphthalene-1,7-disulfonic acid (C) was dissolved in the mixture of 200 parts of cool water and 35 parts of sodium carbonate, to which the above reagent (B) from Diazotization was then added dropwise. Thereby, the coupling reaction was realized. After the reaction was completed, the monoazo compound of free acid (D) was obtained by filtration.
3. Semi-Reduction:
[0042]
[0043] The monoazo compound (D) was dissolved in 400 parts of water, followed by the addition of sodium hydroxide solution until the solution was strong basic. Reduction was realized with the addition of 8 parts of glucose at 40° C. After the reaction was completed, pH was adjusted to 7.0 and then filtration. The compound of free acid of formula (1), with λ max at 530 nm in water, was obtained.
EXAMPLES 2 TO 12
[0044] Repeat the reaction steps of Example 1, but the 2-amino-5-hydroxynaphthalene-1,7-disulfonic acid of reactant (C) is replaced with the following reactant (C) as shown in Table 1. After completed the reaction, the reaction solution are filtered and dried to obtain the products of formula (2) to formula (12) as shown in Table 1. The A max of the compounds of formula (2) to formula (12) in water were presented in Table 1.
[0000] TABLE 1 Example Reagent (C) Product λ max 1 Formula (1) 530 nm 2 Formula (2) 600 nm 3 Formula (3) 538 nm 4 Formula (4) 600 nm 5 Formula (5) 555 nm 6 Formula (6) 575 nm 7 Formula (7) 532 nm 8 Formula (8) 522 nm 9 Formula (9) 532 nm 10 Formula (10) 585 nm 11 Formula (11) 585 nm Example12 Formula (12) 540 nm
The following is the structure of formula (1) to (12) compounds:
[0000]
[0045] The following Examples 13 to 24 are related to the preparation of the dye type polarizing films of the present invention and the measurement of light polarization.
[0046] According to Example 13 to 24, the polarizing films can be formed from the obtained dyes in Examples 1 to 12, with which other dyes work or not. In the following Examples, UV-2550 UV-VISIBLE of SHIMADZU was used for the measurement.
[0047] “T” is the light transmittance at one wavelength; “Ts” is the light transmittance of one polarizing film.
[0048] T parallel: the light transmittance of two polarizing films overlapping each other in the same direction. It is called “parallel light transmittance”.
[0049] T cross: the light transmittance of two polarizing films cross-overlapping each other perpendicularly. It is called “cross light transmittance”.
[0050] “V” is the value from the calculation according to the following equation where T parallel and T cross is measured at λ max:
[0000] V =(√{square root over ( )}(( T parallel− T cross)/( T parallel+ T cross)))×100
EXAMPLE 13
[0051] The polyvinyl alcohol film of 75 μm thickness, Kuraray vinylon 7500 made from Kuraray, was stretched five-fold longer in one vertical direction and the base material of the polarizing film was obtained. The polyvinyl alcohol film in strain form was dipped in the 65° C. solution of 0.025% azo compound of formula (1) made from Example 1 and 2.0% sodium sulfate (served as a dyeing agent). Then, the film was dipped in 7.5% boric acid at 65° C. for five minutes, followed by taking out the film. The polarizing film was obtained after it was washed with 20° C. water for 20 seconds and dried at 50° C. The characteristics of the polarizing film are V=99.97 and Ts=45.07. The polarizing film with high-polarized efficiency does not discolor under the high-temperature and high-moisture condition.
EXAMPLE 14 TO 24
[0052] The same steps as Example 13 obtained the polarizing films with the azo-dyestuff compounds of formula (2) to (12), replacing formula (1) in Example 13. Herein, the polarizing films constituted from the azo-dyestuff of formula (2) to (12) in Table 2 were obtains. The light polarization character of the dye type polarizing films was presented in Table 2.
[0000]
TABLE 2
The polarization character of the polarizing films
Example
Polarizing film of azo-dyestuff
λ max
V
Ts
13
Polarizing film of formula (1)
530 nm
99.97
45.07
14
Polarizing film of formula (2)
600 nm
99.57
45.53
15
Polarizing film of formula (3)
538 nm
99.97
46.21
16
Polarizing film of formula (4)
600 nm
99.61
45.45
17
Polarizing film of formula (5)
555 nm
98.74
43.28
18
Polarizing film of formula (6)
575 nm
99.11
45.18
19
Polarizing film of formula (7)
532 nm
99.84
45.30
20
Polarizing film of formula (8)
522 nm
99.00
43.65
21
Polarizing film of formula (9)
532 nm
99.04
38.56
22
Polarizing film of formula (10)
585 nm
99.12
46.52
23
Polarizing film of formula (11)
585 nm
99.56
41.32
24
Polarizing film of formula (12)
540 nm
99.90
42.43
[0053] According to the result of the measurement in the above table, the polarizing films with the azo dyestuff compounds in the present invention exhibit high-polarized efficiency.
[0054] From the foregoing description, regardless of the objects, the techniques, the effects or the skill aspects and developments, the present invention is distinctive with respect to known skills. Although the present invention has been explained in relation to its preferred embodiment, it is to be understood that many other possible modifications are variations can be made without departing from the scope of the invention as hereinafter claimed.
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The present invention relates to a azo dyestuff compound of the following formula (I), of which the free acid is represented by the following formula:
wherein R 1 , R 2 , R 3 , R 4 , and n are defined as in the specification. The azo dyestuff compound of formula (I) of the present invention is used for preparing polarizing film. The present invention also relates to a polarizing film comprising the azo dyestuff compound of formula (I), which has excellent degree of polarization.
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PRIORITY CLAIMS
This application is a continuation of and claims priority from U.S. patent application Ser. No. 13/181,543, titled “Systems, Devices and Methods for Providing Access to a Distributed Network”, filed on Jul. 13, 2011, which is a continuation of and claims priority from U.S. Pat. No. 8,014,284, titled “Cellular Network System and Method”, issued Sep. 6, 2011, which in turn is a national phase application of PCT/IL2009/000438 filed on Aug. 12, 1999, all of which are hereby incorporated by reference into the present application in their entirety.
FIELD OF THE INVENTION
The invention concerns systems for creating cellular distributed networks and methods for controlling their installation and operation. The invention concerns in particular add-on base stations that allow the creation or expansion of such networks.
BACKGROUND OF THE INVENTION
Currently, it is relatively expensive, time consuming and difficult to install cellular networks. The network installation is especially problematic in highly populated urban areas.
Cellular systems use base stations to establish an RF link between each user in the cell and the cellular wired network. These base stations use a relatively high transmit power, to overcome propagation losses in order to achieve a reliable link. This high RF power, however, may be harmful to people nearby. Moreover, it may interfere with other electronic equipment. These may be part of the reasons why people object to the installation of base stations in populated areas.
In highly populated areas there is a need for more base stations, more closely located to each other. As more users are to be served in a specific area, the cells are made smaller, and more base stations have to be installed.
Therefore, the objection of the public to the installation of additional base stations is a serious impediment to the development of a cellular network.
Moreover, in highly populated areas the real estate is usually expensive.
It requires a large investment to install base stations in these areas and to install the wiring as required.
Once the base stations are installed, it may be required to service them.
One can appreciate the high maintenance cost for a multitude of base stations located in a highly populated urban area.
Heretofore, a large distributed network required a plurality of large switchboards to make all the required connections. As the number of cells and users increase, the number and complexity of switchboards increases as well.
There is a large number of concurrent calls that have to be supported. This further increases the cost of setting up and operating a cellular network.
It is an objective of the present invention to facilitate the installation and expansion of distributed cellular networks, especially in highly populated urban areas.
Another problem in cellular systems is the relatively high transmitted power of the mobile phones. The transmit antenna is close to the user's head, and the RF radiation may have undesirable effects.
As the distance to a base station increases, the mobile transmitter has to transmit at a higher power. Thus, from the radiation hazard viewpoint, it would be desirable to have more base stations, more closely related. This would allow transmission at lower power. There are problems to adding base stations, however, as detailed above.
It is another objective of the present invention to achieve a reduction in the mobile phone transmit power, by using more base stations that are more closely located to each other.
DISCLOSURE OF INVENTION
It is an object of the present invention to provide a system and method that facilitate the installation of distributed cellular networks, especially in developed and highly populated urban areas, using a structure and method implemented with an add-on base station. This may also allow the public at large to participate in providing telecommunication services.
Basically, the system uses the existing infrastructure, for example cable TV, Internet connections and phone networks to provide additional wireless coverage.
According to the invention, the public can participate in providing the function of add-on base stations. These public-owned and public-operated base stations complement a cellular network, thus increasing the density of base stations to provide better coverage with smaller cells.
A novel network structure allows the inclusion of these public-operated base stations within a distributed cellular network.
Call coordination means are used to control the operation of the network.
A distributed network may incorporate the novel base stations within a conglomerate of cellular nets, wired telephone networks and an Internet.
A novel feature of the base station is an unique property of each device. This allows its use as an add-on base station. In prior art, each phone had an unique identity, however the base stations had no unique properties. Each base station in prior art was distinguished based on its fixed location and wiring; there were no distinguishing means in the base station itself. In the novel approach according to the present invention, however, there are base stations that are add-on units to be added to a network by various persons or firms.
The location of each such unit is not known a priori; its very existence has to be announced to the network. A base station with an unique identity allows the network to keep track of the addition of each new base station.
Each novel base station includes means for providing an incentive to the public to acquire and operate them, so as to enhance the cellular network. Using an economic incentive (for example, payment to the owner of a base station for use of his/her device) will stimulate people to operate these base stations. Thus, parts of the public will no more object to the installation of base stations. Rather, people will participate in the development of the cellular network.
According to another aspect of the invention, a payment system is disclosed, that uses digital tokens or prepaid digital documents. Tokens may be downloaded from a center, and the whole process may be made transparent to the user.
Using a multitude of base stations, each for a small area, allows to reduce the transmit power of each station. Thus, people will no longer have to worry about the harmful effects of RF radiation.
It may be easier to obtain licenses to operate base station that use a lower transmit power.
Moreover, it is possible to achieve a reduction in the mobile phone transmit power, by using more base stations that are more closely located to each other.
Furthermore in accordance with the invention, the object is basically accomplished by using the existing telecommunication infrastructure that is available in developed areas.
In these areas, there are available a large number of telephone lines as well as Internet links. These telecommunication facilities are not used all the time. Provided the right incentive, people will offer these facilities for other people's use in cellular links.
Heretofore, a large distributed network required a plurality of large switchboards to make all the required connections.
A novel approach uses a cellular coordination center that does not perform the actual call switching.
Rather, the new center just provides the information required for making a call. Thus the workload on the center is greatly reduced. Smaller, simpler and lower cost switchboards may be used.
In some cases, the switchboards may be eliminated altogether.
A first user is given an Internet address of the other party and may connect it directly. This achieves a direct link from one base station to another, through IP. It may also be possible to connect users through the same base station.
Prior art teaches how to connect two computers that are located at fixed locations. The present invention discloses a structure and method for connecting mobile units, using a center for coordinating the connection.
The technology in the present disclosure may be used for the transmission of voice, data, multimedia or a combination thereof.
Further objects, advantages and other features of the present invention will become obvious to those skilled in the art upon reading the disclosure set forth hereinafter.
DESCRIPTION OF DRAWINGS
The invention will now be described by way of example and with reference to the accompanying drawings in which:
FIG. 1 illustrates a distributed cellular network.
FIG. 2 details the functional structure of a novel base station.
FIG. 3 details another embodiment of the base station.
FIG. 4 illustrates the physical structure of a base station.
FIG. 5 details a cellular to cellular link.
FIG. 6 details a cellular to regular phone link.
FIG. 7 details a link to an IP phone.
MODES FOR CARRYING OUT THE INVENTION
A preferred embodiment of the present invention will now be described by way of example and with reference to the accompanying drawings. Some of the features in the example refer to voice transfer.
It is to be understood, however, that the technology in the present disclosure may be used for the transmission of voice, data, multimedia or a combination thereof.
FIG. 1 illustrates a distributed cellular network providing, in this example, communications between a mobile user 11 , a fixed user 12 and a fixed user 13 .
A communication network may include, for example, a cellular network 22 , a telephone network 23 and an Internet network 24 , all linked to each other.
Throughout the present disclosure, Internet refers to any IP network, that may be for example the Internet or an Intranet.
User 11 is connected through a regular base station 21 to the cellular network 22 . Users 12 and 13 are each connected to the telephone network 23 and an Internet network 24 , respectively. Since all these networks are connected to each other, communication links may be provided between the above users. The link to user 11 is wireless, whereas the link to user 12 is wired. The link to user 13 may be implemented with various means.
An existing network may include, for example, an IP network, such as the Internet, or Internet over cables, or a wired telephone network. Voice communication may be conducted in a voice over IP method using a known technology. Basically, the voice is digitized, sometimes compressed, and cut into packets of data.
The packets are sent over an IP network to their destination.
It is possible that some packets are lost during the routing, and that the packets are received in a different order. However, if not too many packets are lost, the voice quality remains OK. A buffer is usually enough to compensate for the re-ordering of packets.
The above description refers to communications systems as known in the art.
The novel approach allows to expand the above network, for example with the addition of new base stations 41 , 42 and 43 .
The add-on base stations 41 , 42 and 43 illustrate three types of additions to a cellular network. These are three ways the public can participate in the network to enhance its capabilities.
Add-on base station 41 allows to connect a mobile user (not shown) to the existing telephone network 23 . The device includes a wireless link with an antenna to connect to a mobile user, and a wired link to connect to an existing communication network.
This base station may be owned and operated by an independent person or organization. Once this device, the base station 41 , is bought and operated by its owner, it generates a wireless cell in its surroundings. The device will connect a mobile user in that cell to the telephone network 23 , and to any other network and/or user that may be connected to network 23 , either directly or indirectly.
Any person or firm or other entity that has a telephone line (a connection to network 23 ) can buy an add-on base station 41 and connect it to the phone line, to create a new cell in the communication network. Thus, the public, on their own initiative, may add wireless cells to the network.
Thus, our box achieves the function of a cellular base station in a distributed cellular network. It is also a micro-center for routing calls, as detailed below.
The owner of the box connects it to an IP network to expand the existing cellular infrastructure—now a user can connect through the new base station to an Internet, to establish a link with a remote user.
It is assumed that all new base stations are connected to an Internet, since it is in widespread use. A user may connect to an Internet in various ways, for example using a telephone line, a cable TV channel, wireless links etc.
Possible Internet links include the package delivery link and the TCP. Voice links usually use the former link, since in the latter there may be a delay.
In a highly populated area, where there are many phone lines and a numerous population, there is a great probability that many people will buy the novel base stations to generate many new wireless cells.
Thus, new base station 41 adds a new wireless cell in a location where there is available a link to the telephone network 23 (a phone line).
Base station 42 illustrates another type of network enhancement. It connects between an Internet 24 and the telephone net 23 . This allows a remote caller (not shown) to place a call to a phone in the neighborhood of base station 42 : That remote caller connects base station 42 over the Internet 24 , and requires a connection to a phone close to that base station.
This achieves a lower cost communication link, since it comprises an Internet link that is low cost, and a local phone call from base station 42 . It avoids the high cost of long distance phone calls. This type of base station is useful in the implementation of the present invention.
New base station 43 illustrates yet another type of network enhancement. It generates a wireless cell that is directly connected to an Internet 24 .
Thus, new base station 43 adds a new wireless cell in a location where there is available a link to an Internet network 24 .
The system uses the existing infrastructure, for example cable TV, Internet connections and phone networks to provide additional wireless coverage. The above detailed structure and method may be used for other networks as well. These may include, among others, wireless links, satellite links, cable TV links, fiber-optics or a combination thereof.
Thus, new base stations 41 , 42 and 43 allow to use the existing telecommunication infrastructure in developed areas, to enhance the cellular network.
Private individuals or firms or other entities that have access to existing communication channels and do not use those channels all the time, may contribute to a cellular network by providing access to those channels. The novel system includes means to offer an incentive to people, to motivate them to install and operate the base stations. These include means for collecting a payment for services rendered with the base station.
Thus, it is possible to install or expand a cellular network without the need for a large investment in infrastructure. Rather, the new network is based on the existing infrastructure, for example a telephone network, a wireless network, Internet or a combination thereof.
Usually, existing networks have spare capacity. A user does not speak all the time. Therefore, existing networks offer a great potential for expansion, by supporting new cellular networks.
Prior art cellular systems are easier to install in sparsely populated areas, where there is no problem of interference, base stations installation etc. These systems are much more difficult to install in towns or other highly populated areas, where there are the problems cited above. The present invention solves the problem of cellular installation and achieves best performance in the densely populated areas that were difficult to address in the past.
The very population that may have opposed to the cellular net, are now helping the setting up of the new cellular network.
According to the new concept, small cells are thus created in cities or other populated areas.
The maintenance cost is greatly reduced. The system operator is no longer responsible for the maintenance of a multitude of base stations located in a highly populated urban area. Rather, each owner of a private base station is interested to keep his/her equipment in working order. If there is a problem, the owner will see to repairs or a replacement.
In a preferred embodiment, simple and low cost base stations are used, that are expendable—when a malfunction is detected in a base station, the unit is discarded and replaced with a new one.
The novel approach or method allows for a rapid deployment of a cellular network. There is no time-consuming work to be done, to create a new infrastructure from zero.
The new system does not need a plurality of large switchboards to make all the required connections. In prior art systems, as the number of cells increases, the number and complexity of switchboards increases as well. There is a large number of concurrent calls that have to be supported. This adds to the cost of setting up and operating a cellular network.
The new system, however, uses the switchboards in the existing infrastructure for call switching. Therefore, there is no need to add costly switchboards.
There is a need for a coordination center that issues information relating to completing a call as required. Alternately, a plurality of centers may be used. These centers only provide information prior to a call, and do not take part in the actual link being formed. Thus, simpler and lower cost centers are required.
This novel feature may achieve a large reduction in the investment required to install or expand a cellular network.
The centers store information for each base station, including the telephone number used by that station. This information may be advantageously used to generate new links, to help one user to locate an IP base close to the desired destination.
The novel centers are also responsible for price setting, as determined by an operator there. The information regarding prices of use of the net and the additional, private base stations, is disseminated as digital documents encrypted so as to prevent tampering with.
The centers are also responsible for tracking down malfunctions in the cellular network. If a base station would not respond or would not operate correctly, that information is brought to the attention of the center by related parties. The center will disseminate that information, to help user form communication links with reliable channels and base stations only.
The new centers may initiate calls to the various base stations, to verify their correct operation.
Thus, the new cellular centers correlate and guide the operation of the users in the net, in real time.
Usually, a link will be formed with one switchboard at the source (the person who initiated the call) and a switchboard at the destination. Additional switchboards are usually needed in between the above switchboards. These are existing switchboards, that are part of the existing infrastructure.
The cellular links thus formed may be used for various purposes, for example to transmit voice or data.
A problem in a large network is the coordination of all the additions to the cellular network. One can appreciate that a multitude of cells, provided by many people, may be difficult to use and would require complex systems to route all the calls taking place concurrently. Usually, this would require a plurality of large switchboards to make all the required connections.
A novel approach uses a cellular coordination center 3 that does not perform the actual call switching. Rather, the new center 3 just provides the information required for making a call. Center 3 (or a network of such centers) stores information regarding the various base stations, their location and coverage, availability and connections. When a user places a call, he demands information from center 3 . Center 3 provides the required information for placing a call, including a base station close to the desired destination and more, as detailed below.
After providing the information to the caller, center 3 does not participate in the actual call routing; rather, this is performed by the caller, using the existing network infrastructure.
Thus the workload on the center 3 is greatly reduced. Smaller, simpler and lower cost switchboards or cellular coordination centers may be used.
In some cases, the switchboards may be eliminated altogether.
A first user is given an Internet address of the other party and may connect it directly. This achieves a direct link from one base station to another, through IP. It may also be possible to connect users through the same base station.
The phones of the network are basically similar to existing cellular handsets, except minor changes as detailed below.
Regarding the base stations: In prior art cellular networks, the switchboards are always necessary in order to connect between cellular phones.
In the new system, communications may take place between cellular phones without the intervention of switchboards. This may result in faster, more effective communications.
Add-on base stations can be installed and owned by the cellular network operator, but in a preferred embodiment, the base stations are sold with the cellular phone, or without it, to anyone—private persons or firms for example.
People will have an incentive to connect the base station in their home/office, since they will get royalties from the cellular network operator.
Preferably, the size and shape of an add-on base station is similar to that of a cordless telephone base. This may achieve an easy to use device, whose operation is familiar to the user.
Structure and Operation of the Cellular Center 3
Unlike presently used cellular centers, the center 3 of the novel network does not need to carry the role of a switchboard. Existing switchboards in a cellular or phone system may be used as usual, as well as regular IP routing. The new center 3 coordinates the operation of the new base stations like 41 and 43 as illustrated.
The duties of the cellular centers 3 include, among others: a) Network integration and planning, b) Implementing a price policy, c) Network operability, d) Manager of phone locator. (In case of incoming calls).
DETAILED DESCRIPTION
a) The Cellular center 3 knows the current physical location of all add-on base stations, and is aware of the status of each base station (i.e. is available or not available, optionally processing a call etc.).
There may be a trade-off between the desire to keep the center updated, and the need not to overload it. If too high a frequency of reporting to the center is used, this may achieve a center that is updated to the last minute changes, however a large expensive center may be required.
Alternately, it is possible to limit the rate of updates and the type of events that require a report to center. The center does not have to know of any minute change in a base station.
For example, if a base station is busy, but the center is not aware of it, the user may use an alternative base station.
b) The cellular center is responsible for the price policy.
It determines and publishes the cost for each operation over the network. The updated information may be transferred over an Internet, or may be available to add-on base stations.
The information may be dispersed between units in the network. In each transaction, the parties thereto will check the date of each price list. The more updated price list will be transferred to the other party. Thus, the new price list or policy will gradually expand throughout the network.
c) The cellular center is responsible to actively check, once in a while, the availability of base stations and their operability (see if they work properly).
d) One of the main tasks of the cellular center is to give the function: when given a “cellular phone number”, it is able to return the IP address of a base station, that has radio contact with it. Alternately, it may return a message that the phone is in the “out of coverage area”.
A call processing method is detailed below with reference to FIGS. 5, 6 and 7 .
Data Security
Each phone, base station and the cellular center 3 may have their own digital certificate, which binds a cryptographic public key, with an identifier.
The certificate may also contain information such as their phone number or identity. The extra information can also be included in other digitally signed digital documents.
In this way the packets of voice originating from the phone, can be encrypted by the destination public key to the other phone, ensuring privacy. They can also (or alternatively) signed by the originator's private key, to ensure authentication (and possibly non-repudiation).
A phone user may require that all incoming or outgoing calls be authenticated and/or encrypted.
The control channel includes the information exchanged between base stations, phones and/or centers.
The control channel can be encrypted at the base stations, the centers and/or the phones.
The phone can send back to the base station the necessary changes (such as a cell change). The communication between the phone and its base station can also be encrypted.
It is possible to preserve the anonymity of the caller and the addressee, using the following method:
A. A caller sends a request to connect to a specific addressee, using a message encrypted with the public key of a center 3 . The message also includes the identification of the caller.
Nobody can read this message, since it is encrypted.
B. the center decrypts the message, identifies the caller and the addressee.
C. the center composes a message for the addressee and encrypts it with the public key of the addressee. The message is then sent to base stations that may be in contact with that addressee.
The actual policy in use may vary from network to network. A search path may be followed, according to information from past activity for example.
D. the base station transmits the message “as is” or in a modified form.
In any case, the encrypted section is preserved—the base station and other phones in the area will not know who is the caller and who is the addressee.
E. only the designated addressee will be capable to decrypt the message, and will be thus notified of the attempted connection. Other phones, that do not possess the required private key, will not be able to decrypt the message, and will thus know that the message was not addressed to them.
F. if the addressee decides to answer the call, he sends a response message, encrypted with a known public key—for example that of the center, or may ask the base station to reply to that call.
G. the center sends a message to the caller, with information to allow him to implement the connection with the addressee.
In another embodiment of the invention, the addressee may contact directly the caller.
The above method preserves the anonymity of the caller and the addressee. Although the communication may pass through various switchboards and base stations, none will know the identity of the parties to the conversation, except the cellular center. The center may know about the inquiry, but it will not know whether a communication actually did take place between the parties involved.
The subsequent dialog or data transfer may be en clair; it is believed that the identity of the parties to a communication may be more important than the actual information being transferred. Thus, for an eavesdropper the dialog itself may be meaningless if the identity of the parties involved is kept secret.
Thus, all the cellular phones are open and continuously receive the various messages transmitted from a base station in step (D) above. The messages decryption takes computer power, so that it may waste the battery power.
To save on battery, the phones may be divided into a predefined number of groups, for example 1,000 groups. The message to a phone may include a short header that indicates the addressee group. This is a short number that is easy to decrypt; a telephone will decrypt the whole message only if the header of the message corresponds to the group of that phone.
To improve security, the cellular center 3 may accept a request to locate phones (locate nearest IP) only from base stations. The base stations that help to locate a phone, (or the phone itself) may do so only if requested by the cellular center, or by some other authorized entity.
Thus, in step (B) the center checks the authorization of the caller to sent the request; only if the caller is authorized, then the center will proceed to execute step (B); otherwise go to step (H). The authorization may be checked using authorization tables kept at the center for that purpose.
The above means help achieve privacy in a distributed network—it prevents a user's location from being divulged to others.
The cellular center 3 can issue a certificate (an operating license) or another digital document, to the effect that “this phone/base station is part of my network and is in working order” to all the devices connected thereto. The certificates may have a short expiration date, of 1 day for example. This gives the center 3 control over the phones and base stations, that may be disconnected at short notice.
This allows a phone to ask the services of a base station only if it has an updated operating license. Similarly, a base station can verify that the phone is operating properly.
This is one way that a cellular center can exclude “badly behaving” devices from the network. Devices may be otherwise disconnected or excluded for other reasons, as programmed into the center's operating program.
Billing
An important aspect of the present invention is the means for paying to the owner of the add-on base station for his/her services. This provides the incentive for acquiring and operating these base stations.
Since the sessions are encrypted, the payment process can be performed in a way similar to that used with smart cards in prior art. An encrypted session is akin to a point to point, secure link.
Thus, the base station includes means for accepting a payment and for displaying to the user information relating to the payments received.
Using encryption and digital documents, it is possible to reliably implement the payment method as detailed in the present disclosure, while preventing impostors or others who may present false payment means. This may help prevent stealing of calls, that is a problem in present systems.
Further means to prevent calls stealing is the caller ID and destination ID. That is, in the novel system both the identity of the caller and the destination may be known. This may prevent or intimidate a potential thief, who may know that his actions will be recorded and detected.
A possible method of billing is by way of money or tokens.
Digital documents may be used that correspond to cash money or to a credit or right to use the network at someone's expense, or may represent phone tokens having a specific monetary value each.
These documents may be encrypted or signed so as to allow the owner of the base station to receive payment for services rendered.
The phone may download tokens or money from the center or from a plastic card or a smart card or by other means. These payment means may be stored in the phone for subsequent use.
When originating a call, or otherwise as stated in the cellular center policy, the phone would send tokens to the base stations in the way to the other phone.
In this way he pays for the session on-line and in real time.
The center can profit since for a certain amount of money it will give a certain amount of tokens (and take its profit).
Base stations receive payment, and can later redeem the tokens from the cellular center back to money, or receive new tokens for their owner instead, for the owner's use in his/her communications over their cellular phone. Redeem of the tokens is a preferred embodiments, since in this method the center's profit is assured.
The billing policy can be written digitally by way of a digital document, with a date (and a short expiry date), signed by the cellular center. This policy would be stored in all base stations and phones, and they set the prices (by means of tokens) that the phones pay.
When two units interact, they can compare the time stamps or the version of the policy held by each unit. Thus the policy is updated as necessary and there would not be any dispute between the parties.
The information may be dispersed between units in the network. In each transaction, the parties thereto will check the date of each price list. The more updated price list will be transferred to the other party. Thus, the new price list or policy will gradually expand throughout the network.
The billing unit can be a “black box” inside each apparatus. This black box can be tamper-free, including means to destroy its contents or delete the information therein, if someone tries to tamper with it. This ensures that it can be trusted to work under commands given in policy documents.
The billing unit may be implemented as part of a call controller 54 in the base station, see FIG. 2 .
In another embodiment, the black box function may be contained within a smart card.
The above structure and method may be either used to enhance an existing cellular system or to create a new cellular system altogether.
FIG. 2 details, by way of example, the functional structure of a novel base station (like base station 41 , 42 or 43 of FIG. 1 ).
The basic function of the station is to connect a first channel 51 with a second channel 52 . Either channel may be wired or wireless, using various technologies.
The channel electronic means 53 implements the actual communications to connect between the channels 51 and 52 . A call controller 54 supervises and controls the operation of means 53 , according to commands received from a user through the control inputs 541 for the base station.
A billing processor 55 computes the fee or payment the base station owner is entitled to, according to the amount of traffic on the channels 51 , 52 , and the method or policy as set in the billing document.
Thus, as more communication services are provided to the public, the owner of the base station will receive a larger fee accordingly.
A display 56 may be used to display the payment due or payment received for the calls placed by other users.
A novel feature of the base station is a unique property in each device. This unique property may be stored, for example, in either the call controller 54 or the billing processor 55 .
This unique property allows to use the base station as an add-on device. In prior art, each phone had an unique identity, however the base stations had no unique properties. Each base station in prior art was distinguished based on its fixed location and wiring; there were no distinguishing means in the base station itself.
In the novel approach according to the present invention, however, there are base stations that are add-on units to be added to a network by various persons or firms. The location of each such unit is not known a priori; its very existence has to be announced to the network. A base station with an unique identity allows the network to keep track of the addition of each new base station. The unique identity helps manage the expanding network.
Various means may be used to achieve the unique identity of each add-on base station. For example, an unique number may be stored in memory means in units 54 or 55 . Alternately, a digital document may be stored therein. A smart card with an unique number or document may be inserted in the base station to activate it.
A plurality of users may be served using wideband channels having the capability to serve several users at once. For example, channel 51 may be a wireless channel capable of communicating with several users using TDMA or FDMA or CDMA. Channel 52 may be an Internet connection capable of connecting to several destinations simultaneously.
Alternately, more than two channels may be used. This may allow a base station to concurrently communicate with more users and/or networks.
It is also possible to have other types of channels, for example wired phone lines.
FIG. 3 details another embodiment of the base station. The RF channel includes an antenna 61 and an RF unit 62 . The main box 63 includes the electronics for connecting the RF channel to the phone line connection 64 and the IP connection 65 .
In a preferred embodiment, the phone line connection 64 is optional.
An add-on base station may only include the RF channel (to connect to a mobile user in a cellular wireless system) and the IP connection 65 . The base station may also be connected to an optional source of electrical power.
The size of the base station can be not larger than a regular cellular phone. It has the following components: a) Main box, b) IP connection, c) antenna, d) phone line connection.
Some of the above components may be optional, as required for the desired function as an add-on to a cellular network.
FIG. 4 illustrates an embodiment of the physical structure of a novel base station, including a cellular phone 71 and a base 72 . A connector 721 is used to connect the two devices.
The owner may use the cellular phone as usual, to communicate as desired. When not in use, he/she may insert the phone 71 into the base 72 to form a base station: the phone 71 communicates with mobile users, and the base 72 is connected to wired networks through a phone line connection 64 and/or an IP connection 65 . The device may further include mains power connection 722 .
This system requires a modified phone, that has a capability to operate as a base station, both in transmit and receive modes. In cellular systems, the mobile phones transmit in a first frequency band and receive in a second frequency band, whereas the base station transmits in the second frequency band and receives in the first band.
Thus, a cellular phone cannot communicate directly with another phone. Accordingly, in the present invention, the phone 71 includes means for transmitting and receiving in the way used by base stations when it acts as a relay station.
Moreover, the phone 71 further includes means for transmitting and receiving control signals as required in a cellular network, to establish a communication link with a mobile phone and control that communication. The control signals may include, for example, power control, link establishment and disconnection. The control signals are specific to each cellular network like GSM, AMPS, CDMA etc.
The phone 71 may include means for performing one cellular link at a time, or it may include means for communicating at once with several mobile phones. In the latter case, it will function as a base station for several mobile phones located in its surroundings.
The above description refers to one embodiment, where the RF link is implemented with a modified cellular phone 71 .
In another embodiment (see FIGS. 2 and 3 ), no cellular phone is used to implement the RF link with other phones. Rather, a complete base station includes all the RF transmit and receive means to allow it to communicate with a mobile cellular phone. The base station may include means to allow it to concurrently communicate with several mobile phones.
Furthermore, the base station may include means for charging a battery in the cellular phone. Thus, as the phone is inserted in the base, its battery is charged and concurrently the phone may be also used to expand a cellular network.
FIG. 5 details a cellular to cellular link that may be implemented over the system as illustrated in FIG. 1 .
A link may be established between a first (mobile) user 11 and a second (mobile) user 14 . User 11 communicates with new base station 43 , that is connected to an Internet network 24 .
User 14 , who is located in another area, communicates with new base station 44 , that is also connected to an Internet network 24 . Thus, a communication link is established between users 11 and 14 through the IP network 24 . This is a low cost, fast link.
A Call Processing Method
Following is detailed a method for conducting a cellular to cellular call over the network.
A. The phone 11 which is initiating the call, is accessing the nearest base station 43 by means of radio communication.
It identifies and requests a (voice) connection to the other phone number 14 . The number may be either en clair or encrypted. For an encrypted session—see details in the “Data Security” section.
B. The base station 43 then contacts the cellular center 3 (see FIG. 1 ), asking the IP address of the nearest station 44 to the destination phone number 14 .
C. There are several possibilities:
C1. The cellular center 3 returns an answer, that the destination is not available.
In this case either the base station 43 is notifying the requesting phone 11 of the situation, or the center returns an alternate IP address.
The alternate IP address can be the destination voice mail, or a recorded message, for example: “The phone you have reached is not available right now, please try later.”
It is also possible that the IP indicates a link to advanced services, such as “follow me” etc.
C2. The destination is available. In this case, it is possible that the return answer would come either directly from the base station 44 that is in contact with the phone 14 , or be returned by the center 3 .
In case an IP was returned, the base station 42 contacts the destination station over the network, and “calls” the phone 14 .
If the phone 14 is taken off the hook, then packets of voice are exchanged between the base stations, and are forwarded from and to the phones 11 and 14 , so that a phone session is established.
In case the phone 14 refused the call, the originator base station 43 can try to locate the phone again through the center, or ask to see if there is a voice mail IP from the center. The phone 14 refusing the call can also state another IP or number where it may be contacted, or a voice mail.
To preserve the privacy of the addressee, the phone 14 may ask the center not to disclose its refusal. Rather, the center may announce the caller that the addressee is not available.
Moving Between Cells (Base Stations)
Let us assume that a mobile phone has a link with a first base station. It may happen, during the conversation, that the phone detects that it receives the first base station at a low power, that is at a power lower than a predefined threshold.
In that case, a program in the phone may run a background search for an alternate base station. If it finds a second base station at a higher received power, then the phone will ask it to continue the call. It will send packets from the new station, and try to inform the old station of the change.
Alternately, the new base station can inform the old base station of the transfer of the call to it.
The other party's base station is informed by the phone or by the base station of the new IP address of new base station.
Thus the link is disconnected from the first base station and a new connection is established with the second base station, to improve the quality of the link. It is assumed that a higher received power indicates a link with an improved communication quality.
Locating Base Stations
After a base station was bought by a person or entity, a stage of activating the base station is to be performed. The device is activated when it is connected to and integrated within the cellular network.
The location of base station can be made known to the cellular center 3 using various methods. Several ways are detailed below by way of example.
1. During the registration of a base station, the person that registers the base station would state its location. 2. If the base station is connected to a phone line, its location can be found automatically from the number it is connected to. 3. The station can “listen” to transmissions from other base stations nearby (whose location is already known), and forward the information regarding the identity of received base stations and the power level of each such reception to the cellular center. Using this information, the cellular center can estimate the location of the new base station. 4. Nearby stations (which are already known in the system) can listen to a beacon or transmission from the new station and thus its location can be estimated. 5. A low-cost GPS device (with or without earth radio corrections) can be inserted into the base-stations, so that it would know and report its location.
Method for Locating the Destination Base IP
There are several methods to locate a phone.
1. This can be done in a similar fashion to what is done at present. Since the cellular center knows the location of base stations, it can start a search for the phone from the last place it was known to be.
2. Otherwise, the phone could be “paged” over paging channels, and the phone would reply to the nearest base station, and this reply would be forwarded by that base station to the cellular center.
3. A phone may be required to send a beacon once in a while to the nearest base station, so that the center may know its location.
4. The network may be divided into geographical zones. A city may be a zone, for example. The phone may be required to announce the center when it crosses the boundaries of zones.
Methods for achieving data security and for billing were detailed above.
Secure means as detailed in the “Data Security” section above may be used, to preserve the anonymity of the caller and the addressee. Only the cellular center will know the identity of the parties to a conversation. Even the center will not know whether the conversation actually took place.
FIG. 6 details a cellular to regular phone link. A link is established between a first (mobile) user 11 and a second (fixed) user 12 . User 11 communicates with new base station 43 , that is connected to an Internet network 24 .
User 12 , who is located in another area, is connected to the existing telephone network 23 .
A new base station 42 connects (bridges) between an Internet network 24 and the existing telephone network 23 , wherein the point of entry to the telephone network 23 is preferably in a location close to that of user 12 , so as to achieve a local, or low cost, phone link. Thus, base station 42 achieves a low cost connection between users 11 and 12 .
A cellular center 3 (see FIG. 1 ) may direct user 11 to a base station that is close to the call destination (to user 12 ).
A Call Processing Method—Cellular to Regular Phone
Following is detailed a method for conducting a cellular phone to a regular phone call over the network.
The conversation goes the same as illustrated above for the cellular to cellular link with reference to FIG. 5 , however the center 3 will not return the IP of the base station nearest the destination phone. Rather, the center 3 calculates the nearest base station 42 to the destination phone number 12 and give its IP.
That station 42 is the one that is connected to the phone system 23 , and has agreed to process calls for the cellular system.
The originator base station 43 would connect to the base station 42 , which would act as a gateway station.
The line module in the gateway station 42 will play the role of a cellular phone. The phone conversation can be encrypted up to the gateway station.
A Call Processing Method—Regular Phone to Cellular
Several methods may be used to implement such a call.
1. If there is cooperation with a telephone company, the cellular center 3 can inform it of the phone numbers of all the base stations 42 that have agreed to be a gateway station.
The regular phone user can dial a number with a special prefix, and the call would be routed to the nearest gateway station 42 whose line is available.
The gateway station can know of the destination by means of caller ID, DTMF, other digital way, or that the caller would get another tone signal from the gateway station, and could dial the rest of the number by DTMF identification.
2. Otherwise, it is believed that the telephone company will show at least a measure of cooperation, to the effect that it will contact the caller to the nearest gateway station number. Then, the dialing can be completed with the gateway station identifying the DTMF from the caller.
Since we assume many people will use the new cellular system, it is a reasonable assumption that there will be a gateway station available in the same telephone switchboard of the destination phone, so the call would be local.
3. If there is no cooperation from the telephone company, a 1-800 number can be set up, so that someone could find the nearest gateway station near him.
In other words, the caller would have to call directly to some gateway station, and continue dialing from there, by DTMF for example. The gateway may provide a dial tone to assist this dialing. The gateway may use automatic DTMF recognition for that purpose.
The gateway base station in this case is playing the caller phone to the network. It may also add information such as called ID.
Billing in this case is by the receiver phone, or otherwise as set by policy of the cellular center. It is possible that the caller would pay for the tokens, if the phone company bills him for their cost, and sends that amount to the cellular center. This enables the base stations to bill the cellular center later, if it is by prior agreement.
FIG. 7 details a link to an IP phone. A first (mobile) user 11 may connect to a second (fixed IP phone) user 13 .
User 11 may connect either through base station 41 or base station 43 . The new base station 43 is directly connected to an Internet network 24 . The new base station 41 connects (bridges) between the cellular user 11 and the existing telephone network 23 , which is connected to Internet 24 .
A Call Processing Method—from an IP Phone
Since calls are already over the IP network, people may prefer to use the IP network as their main phone network.
Special apparatus could be made to play the part of base station and phones, all in a regular phones case.
Otherwise, this may be done with PCs with software and with or without hardware (possibly a smart card—to do all the black box part).
Communication to/from an IP phone is the same as regular cellular phones, if implemented in this way, and can also be as outside phones which contact a base station that agreed to act as an IP gateway.
Remarks
Various embodiments of the present invention are possible. Following are several examples.
1. It is possible to create centers of access to the system, which may contain an array of base stations that will function as gateway stations. It is also possible to build antenna towers in areas far from urban areas such as roads.
2. It is possible to include relay option means in cellular phones, in such way that if a phone is far from a cell, but there is an other phone in the way that receives both, it can act as a relay.
This structure is better suited for car phones. It can be also used in handheld phones.
Tokens can be also paid to the relay station that takes part in a communication link.
3. Large systems can be subdivided into smaller systems or by location or by country or another geographical criterion. Connection between those systems can also be done by IP means, if desired.
4. The add-on base stations may be installed in various vehicles. This may achieve cellular coverage in areas that may otherwise not be covered. The device may include means to install in a vehicle, including use of an installed antenna and the power source in the car.
Thus, parked cars may be used as relay stations, with a cellular phone installed in the car acting as an add-on base station.
5. The mobile base stations may include wireless means to connect to each other. A linked channel may thus be achieved, with the base stations acting as relay stations. This may allow communications where the fixed base stations are far apart from each other. This structure allows for a link between moving cars.
6. The add-on base stations may allow surfing an Internet. To achieve this, the base may include communication means for data, voice and/or multimedia. Any type of information may be transferred.
7. The system may be used for encrypted E-mail. An advantage of the present system is that the identity of the parties to that E-mail correspondence are kept secret from the base stations and other factors in the net. Only the center knows the identity of the parties to the E-mail.
The technology may also be used in E-commerce. It preserves the privacy of the parties to a transaction.
8. The system may use a cellular center to coordinate the connections between users. Alternately, a distributed center network may be used.
Advantages
1. Lower Radiation Base Stations
Since cellular cells (each base station) may be quite close to each other, the cellular cells can be small, and reduce the transmission power needed for the base stations, resulting in lower radiation.
2. Lower Radiation Mobile Phones
Since base station are closer, the distance from a mobile phone to a base station is shorter. Thus, the mobile phone may transmit at a lower power.
3. Low Cost Deployment
There is no need for a new infrastructure. That is achieved with low cost base stations, that can be mass produced.
Since people may put these low radiation stations in their homes or offices, there may be no need for licenses from authorities to install these devices. There may be no need to ask for a license to install a high power transmitter or a large antenna.
Since routing may be done for example by IP routing, there is no need for large switchboards. Actually there may be no need for ANY switchboard. Only computers that connect to the network are required, to act as the cellular centers.
There is no need for highly trained personnel to deploy the network.
4. Quick, No Hassle Deployment
Since the system is using existing infrastructure, there is only need to put and connect base stations, which ordinary people can do themselves, just like connecting a wireless phone, the deployment is rapid, without the need to construct and install large antennas.
5. Lower Cost of Operation
There is no need to take care of a large infrastructure and its overhead, like switchboards, carrier lines, etc.
There is no need for personnel or highly trained personnel to manage the network. Since the equipment is so cheap, it can be just replaced.
6. Cheap Air-Fare
Since the overall cost is low, the prices for the end user can be low, and the possibility to earn money from base stations, may be an incentive. Also, as described, connections to/from regular phone system may be done as local calls. Therefore, there is additional savings in payment to phone companies.
It will be recognized that the foregoing is but one example of an apparatus and method within the scope of the present invention and that various modifications will occur to those skilled in the art upon reading the disclosure set forth hereinbefore.
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Systems and apparatus, and methods relating thereto, can be implemented to include base station having a transceiver adapted to establish a radio-frequency link with a mobile telephone; a first interface, separate from said transceiver, that is adapted for communication over the public Internet; and a controller. The controller can be adapted to obtain, from a server accessed via the public Internet, gateway address information for a remote gateway that provides an interface between the public Internet and a network of a telephone service provider and route data from the mobile telephone, over the public Internet, to the remote gateway.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a composition which is in the form of a water-in-oil (W/O) emulsion, which has a viscosity, at a shear rate of 200 s−1 and at 25° C., ranging from 3 Pa.s (30 poises) to 20 Pa.s (200 poises) and which comprises a specific silicone surfactant and has a high water content. The present composition has the appearance of a cream and can be used in particular in the cosmetic and/or dermatological fields.
2. Background of the Invention
In the cosmetic or dermatological fields, it is commonplace to use compositions having the appearance of a cream and which are composed of a water-in-oil (W/O) emulsion comprising an aqueous phase dispersed in an oily phase. These emulsions comprise a continuous oily phase and, therefore, make it possible to form, at the surface of the skin, a lipid film which prevents transepidermal water loss and protects the skin from outside attacks. These emulsions are particularly appropriate for protecting and nourishing the skin and in particular for treating dry skin.
A cream is, in the fields under consideration, a composition exhibiting a degree of viscosity, in contrast to liquid or semi-liquid compositions, such as lotions and milks, or to solid compositions. However, creams in the form of W/O emulsions exhibit the disadvantage of contributing a fairly greasy feel to the skin on application, the oily phase being the external phase. Thus, these creams are generally used for dry skin, since they are too greasy to be used on greasy skin. Furthermore, W/O emulsions do not contribute any freshness and are generally too rich in oils to be used during the summer or in hot countries.
To overcome these disadvantages, the preparation of emulsions with a high water content has been proposed. However, the water content of the compositions cannot be too high for reasons of stability, otherwise a high water content has to be compensated for by the addition of several surfactants or of gelling agents, which can be harmful to the comfort of the final composition and can even lead to problems of cutaneous irritation, in particular, in people with sensitive skin.
A need, therefore, remains for a composition which has the viscosity of a cream and which is provided in the form of a stable water-in-oil emulsion, which comprises a large amount of water and which can be used in the cosmetic and/or dermatological fields, which does not exhibit the disadvantages of the prior art.
SUMMARY OF THE INVENTION
Accordingly, one object of the present invention is to provide a cosmetic or dermatological composition for the protection of the skin which, as an emulsion, does not impart a greasy feeling to the skin.
Briefly, this object and other objects of the present invention as hereinafter will become more readily apparent can be attained by a composition comprises an aqueous phase dispersed in an oily phase containing a silicone emulsifying agent, which composition has a viscosity, measured with a Rheomat 180 viscometer at a shear rate of 200 s −1 and at 25° C., ranging from 3 Pa.s (30 poises) to 20 Pa.s (200 poises), said composition comprising at least 78% by weight of aqueous phase, with respect to the total weight of the composition, including at least 65% of water with respect to the total weight of the composition, and in that the composition comprises, as sole emulsifying agent, the dimethicone copolyol of formula
in which R 1 represents
(C 3 H 6 O)—(C 2 H 4 O) 18 —(C 3 H 6 O) 18 H
p=394 and n=4.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In spite of the presence of a large amount of water in the present composition, the composition of the invention is stable over time. In addition, it has a specific rheological characteristic which renders it useful in the fields under consideration particularly advantageous. This is because, during the application to the skin, the composition “breaks”, that is to say that it suddenly fluidizes under the effect of shearing, which is probably attributable to the phenomenon of rupturing within the emulsion. Thus, the composition of the invention contributes very great freshness to the skin.
The composition of the invention has a viscosity ranging from 3 Pa.s (30 poises) to 20 Pa.s (200 poises). This viscosity is measured with a Rheomat 180, that is to say with the RM 180 Rheomat device manufactured by Mettler.
The composition of the invention comprises at least 78% by weight of aqueous phase with respect to the total weight of the composition and preferably at least 80% of the total weight of the composition. The aqueous phase can constitute up to 92% of the total weight of the composition.
Water constitutes at least 65% and preferably at least 70% of the total weight of the composition.
Furthermore, the aqueous phase of the emulsion can comprise at least one lower molecular weight alcohol such as ethanol, in an amount preferably ranging up to 15%, preferably up to 10% of the total weight of the composition and one or more polyols such as glycerol or propylene glycol in an amount ranging, for example, up to 20%, preferably up to 10% of the total weight of the composition.
Furthermore, the composition of the invention comprises, as sole emulsifying agent, the dimethicone copolyol of formula (I). This dimethicone copolyol can be provided in the form of a mixture with a volatile or non-volatile silicone oil and in particular with cyclomethicones (D4 or D5) and/or polydimethylsiloxanes of different viscosities, in particular 5 cSt and 10 cSt. Suitable such mixtures are commercially available, for instance, those as follows sold by the Dow Corning Company:
(i) a mixture of compound of formula (I), of tetracyclomethicone (D4) and of water (ratio by weight 10/88/2), sold under the name DC 3225C;
(ii) a mixture of compound of formula (I), of pentacyclomethicone (D5) and of water (ratio by weight 10/88/2), sold under the name DC 5225C,
(iii) a mixture of compound of formula (I) and of polydimethylsiloxane 5 cSt (ratio by weight 10/90), sold under the name DC 3225C in 200 Fluid 5 cSt;
(iv) a mixture of compound of formula (I) and of polydimethylsiloxane 10 cSt (ratio by weight 10/90), sold under the name DC 3225C in 200 Fluid 10 cSt;
(v) a mixture of compound of formula (I) and of pentacyclomethicone (D5) (ratio by weight 43/57), sold under the name DC 5185C.
The emulsifying agent of the formula (I) is preferably present in an amount of active material ranging from 0.5-5%, preferably from 0.6-2% by weight with respect to the total weight of the composition.
Although the composition is devoid of any other emulsifying agent, the composition obtained is stable over time.
The ratio by weight of oily phase to emulsifying agent is preferably equal to or greater than 5, preferably equal to or greater than 8.
The oily phase of the composition of the invention can comprise, in addition to the silicone oil, optionally, as a mixture with the emulsifying agent, any kind of oil and fatty substance well-known to one of skill in the art such as oils of vegetable origin, oils of animal origin, synthetic oils and in particular fatty esters, silicone oils, fluorinated oils and/or mineral oils, as well as mixtures of these oils.
The oily phase of the composition of the invention preferably comprises at least one volatile silicone oil generally present in an amount ranging from 6-16% by weight with respect to the total weight of the emulsion, such as, for example, a cyclic silicone, such as pentacyclomethicone, tetracyclomethicone or hexacyclomethicone.
The oily phase can additionally comprise other fatty constituents such as fatty alcohols and fatty acids.
The oily phase is present in the composition of the invention in an amount ranging from 8-22%, preferably from 12-20% by weight with respect to the total weight of the composition.
Another advantage of the composition of the invention arises from the fact that a large amount of electrolyte can be incorporated therein without harming the stability of the composition. Suitable such electrolytes include salts of mono-, di- or trivalent metals and more particularly alkaline earth metal salts such as barium, calcium and strontium salts; alkali metal salts such as sodium and potassium salts, magnesium, beryllium, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, lithium, tin, zinc, manganese, cobalt, nickel, iron, copper, rubidium, aluminum, silicon and selenium salts, and their mixtures.
The ions constituting these salts can be selected, for example, from carbonates, bicarbonates, sulfates, glycerophosphates, borates, chlorides, bromides, nitrates, acetates, hydroxides, persulfates and salts of α-hydroxy acids such as citrates, tartrates, lactates and malates and of fruit acids, or alternatively salts of amino acids such as aspartate, arginate, glycocholate and fumarate.
The electrolyte is preferably a mixture of salts comprising in particular calcium, magnesium and sodium salts and in particular a mixture comprising at least magnesium chloride, potassium chloride, sodium chloride, calcium chloride and magnesium bromide, the said mixture corresponding to Dead Sea salts.
The content of electrolyte, when it is present, generally ranges from 0.5-20%, preferably from 2.5-10% by weight with respect to the total weight of the composition.
The composition of the invention is preferably intended for topical care or treatment. In this case, the emulsion must comprise a physiologically acceptable medium, that is to say compatible with the skin, mucous membranes, nails, scalp and/or hair. In addition, it preferably comprises at least one active principle and is applied in a large number of cosmetic and/or dematological treatments of the skin, including the scalp, hair, nails and/or mucous membranes, in particular for the care of and/or the making-up of and/or the anti-sun protection of the skin and/or mucous membranes, as well as for the preparation of a cream intended for the treatment of diseases of the skin, more particularly of greasy skin (contribution of freshness) and of psoriasis, as product for accompanying the treatment.
Another aspect of the invention is, therefore, a topical composition comprising an emulsion as defined above and at least one active principle.
Other active ingredients which may be included in the composition include, in addition to the electrolytes indicated above, of polyols such as glycerol, glycols such as polyethylene glycol 8, and sugar derivatives, enzymes, natural extracts, procyanidol oligomers, vitamins such as vitamin C, vitamin E, vitamin A and their esters, phosphate and glucosyl derivatives, urea, rutin, depigmenting agents such as kojic acid and caffeic acid, β-hydroxy acids such as salicylic acid and its derivatives, α-hydroxy acids such as lactic acid and glycolic acid, retinoic acid and its derivatives, screening agents, moisturizing agents, such as protein hydrolysates, and their mixtures.
These active ingredient can be present, for example, in a concentration ranging from 0.01-20%, preferably from 0.1-5% and more preferably from 0.5-3% of the total weight of the composition.
In a known way, the composition of the invention can also comprise adjuvants which are normally used in the cosmetic and/or dermatological fields, such as preservatives, antioxidants, complexing agents, solvents, fragrances, fillers, screening agents, bactericides, odor absorbers, coloring materials and lipid vesicles. The amounts of these various adjuvants are those conventionally used in the field under consideration, for example from 0.01-20% of the total weight of the composition. These adjuvants, depending on their nature, can be introduced into the fatty phase, into the aqueous phase and/or into the lipid vesicles.
A further aspect of the present invention is a process for the cosmetic treatment of the skin, hair, nails, scalp and/or mucous membranes utilizing the composition as described above.
Another aspect of the invention is the use of the composition as defined above for the manufacture of a cream intended for the treatment of greasy skin.
When the present composition comprises Dead Sea salts, the composition is suitable in particular for the treatment of psoriasis. Consequently, another aspect of the present invention is the use of such a composition for the manufacture of a cream intended for the treatment of psoriasis.
Having now generally described the invention, a further understanding can be obtained by reference to certain specific Examples which are provided herein for purpose of illustration only and are not intended to be limiting unless otherwise specified. The amounts given in the following Examples are given in percent by weight.
EXAMPLES
Example 1: Pace cream
A. Oily phase
Dimethicone copolyol of formula (I) in
17.5%
pentacyclomethicone and water (10/88/2) (DC 5225 C)
B. Aqueous phase
Sodium chloride
2.5%
Glycerol
5%
Preservatives
0.55%
Citric acid
0.035%
Water
74.415%
Procedure: Phase B is prepared by heating the mixture of sodium chloride, of glycerol and of preservatives in water to 45° C. with stirring until the preservatives have completely dissolved. The mixture is allowed to cool to room temperature and then citric acid dissolved in water is added thereto. Phase A is prepared by mixing the constituents with stirring and the mixture obtained previously is poured into phase A with stirring.
A white cream is obtained which has a viscosity, measured with a Rheomat 180, of 9.94 Pa.s (99.4 poises) at time zero. This viscosity stabilizes after 10 minutes at 7.01 Pa.s (70.1 poises).
Example 2: body cream
A. Oily phase
Dimethicone copolyol of formula (I) in
6.25%
tetracyclomethicone and water (10/88/2) (DC 3225 C)
Tetracyclomethicone
6.25%
B. Aqueous phase
Sodium chloride
2.5%
Polyethylene glycol 8
2%
Water
83%
Procedure: the various phases are prepared and phase B is introduced into phase A with stirring.
A white cream is obtained which has a viscosity, measured with a Rheomat 180, of 4.45 Pa.s (44.5 poises) at time zero. This viscosity stabilizes after 10 minutes at 3.88 Pa.s (38.8 poises).
The disclosure of French priority Application Number 9808418 filed Jul. 1, 1998 is hereby incorporated by reference into the present application.
Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.
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A cosmetic or dermatological composition, comprising:
an aqueous phase dispersed in an oily phase with a silicone emulsifying agent, wherein the viscosity of the composition, measured with a Rheomat 180 viscometer at a shear rate of 200 s −1 and at 25° C., ranges from 3 Pa.s (30 poises) to 20 Pa.s (200 poises), the aqueous phase constituting at least 78% by weight with respect to the total weight of the composition with the water of the aqueous phase constituting at least 65% of the total weight of the composition, and the emulsifying agent consisting of the dimethicone copolyol of formula (I):
wherein R 1 is
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This is a division of application Ser. No. 07/650,337, filed Feb. 4, 1991, now U.S. Pat. No. 5,101,065.
BACKGROUND OF THE INVENTION
Certain 2-(2',3',4'-trisubstituted benzoyl)-1,3-cyclohexanedione herbicides are described in U.S. Pat. No. 4,780,127, issued Oct. 25, 1988; U.S. Pat. No. 4,816,066, issued Mar. 28, 1989; and PCT International Publication No. WO 90/05712, published May 31, 1990 and entitled Certain 2-(2',3',4'-trisubstituted benzoyl)-1,3-cyclohexanediones, with William J. Michaely, inventor and all incorporated herein by reference.
The above-described herbicidal compounds can have the following structural formula ##STR1## wherein R is hydrogen, halogen or alkyl; R 7 through R 12 are hydrogen or C 1 -C 4 alkyl or R 7 , R 8 , R 11 and R 12 are methyl and R 9 and R 10 together are carbonyl; R 1 is C 1 -C 4 alkyl, C 1 -C 4 haloalkyl, --CH 2 CH 2 OCH 3 , --CH 2 CH 2 OC 2 H 5 , --CH 2 CH 2 SCH 3 , or --CH 2 CH 2 SC 2 H 5 ; R 2 is C 1 -C 4 alkyl; and n is the integer 0 or 2.
These herbicides can be prepared by reacting a dione of the structural formula ##STR2## wherein R 7 through R 12 are as defined with a mole of trisubstituted benzoyl chloride of the structural formula ##STR3## wherein n, R, R 1 and R 2 are as defined above.
This invention relates to a process for the preparation of 2-(hydrogen, halogen or lower alkyl)-3-(hydroxy, C 1 -C 4 alkoxy, C 1 -C 4 haloalkoxy, --OCH 2 CH 2 OCH 3 , --OCH 2 CH 2 OC 2 H 5 , --OCH 2 CH 2 SCH 3 or --OCH 2 CH 2 SC 2 H 5 )-4-(alkylthio or alkylsulfonyl)-acetophenones and to the intermediates prepared by the process.
SUMMARY OF THE INVENTION
One embodiment of this invention is directed to a process for the preparation of 2-(hydrogen, halogen or lower alkyl)-3-(hydroxy, C 1 -C 4 alkoxy, C 1 -C 4 haloalkoxy, --OCH 2 CH 2 OCH 3 , --OCH 2 CH 2 OC 2 H 5 , --OCH 2 CH 2 SCH 3 or --OCH 2 CH 2 SC 2 H 5 )-4-(alkylthio or alkylsulfonyl)-acetophenones represented by the following reaction steps: ##STR4## wherein R is hydrogen, halogen or C 1 -C 2 alkyl; R 2 is C 1 -C 4 alkyl; and X is halogen ##STR5## wherein R is hydrogen, halogen or C 1 -C 2 alkyl; and R 2 is C 1 -C 4 alkyl ##STR6## wherein R is hydrogen, halogen or C 1 -C 2 alkyl; R 1 is C 1 -C 4 alkyl, C 1 -C 4 haloalkyl, --CH 2 CH 2 OCH 3 , --CH 2 CH 2 OC 2 H 5 , --CH 2 CH 2 SCH 3 , or --CH 2 CH 2 SC 2 H 5 ; and R 2 is C 1 -C 4 alkyl ##STR7## wherein R, R 1 and R 2 are as defined in step 3 ##STR8## wherein R, R 1 and R 2 are as defined in step 3 or in the alternative, the acetyl and alkylthio ring groups can be oxidized sequentially as follows: ##STR9## wherein R, R 1 and R 2 are as defined in step 3 ##STR10## wherein R, R 1 and R 2 are as defined in step 3 or in the alternative, the alkylthio and acetyl ring groups can be oxidized sequentially as follows: ##STR11## wherein R, R 1 and R 2 are as defined in step 3 ##STR12## wherein R, R 1 and R 2 are as defined in step 3.
Another embodiment of this invention is the intermediate reaction product of Reaction step 1. These trisubstituted acetophenones have the structural formula ##STR13## wherein R is hydrogen; halogen, preferably chlorine; or C 1 -C 2 alkyl, preferably methyl, most preferably chlorine and R 2 is C 1 -C 4 alkyl, preferably methyl or ethyl, most preferably ethyl.
Still another embodiment of this invention is the intermediate reaction product of Reaction step 2. These intermediate compounds have the structural formula ##STR14## wherein R is hydrogen; halogen, preferably chlorine; or C 1 -C 2 alkyl, preferably methyl, most preferably chlorine and R 2 is C 1 -C 4 alkyl, preferably methyl or ethyl, most preferably ethyl.
And another embodiment of this invention is the intermediate reaction product of Reaction step 3. These intermediate compounds have the structural formula ##STR15## wherein R is hydrogen; halogen, preferably chlorine; or C 1 -C 2 alkyl, preferably methyl, most preferably chlorine, R 1 is C 1 -C 4 alkyl, C 1 -C 4 haloalkyl, --CH 2 CH 2 OCH 3 , --CH 2 CH 2 OC 2 H 5 , --CH 2 CH 2 SCH 3 , or --CH 2 CH 2 SC 2 H 5 ; and R 2 is C 1 -C 4 alkyl, preferably methyl or ethyl, most preferably ethyl.
Yet another embodiment of this invention are the intermediate compounds that are the reaction product of Reaction step 4c. These intermediates have the structural formula ##STR16## wherein R is hydrogen; halogen, preferably chlorine; or C 1 -C 2 alkyl, preferably methyl, most preferably chlorine, R 1 is C 1 -C 4 alkyl, C 1 -C 4 haloalkyl, --CH 2 CH 2 OCH 3 , --CH 2 CH 2 OC 2 H 5 , --CH 2 CH 2 SCH 3 , or --CH 2 CH 2 SC 2 H 5 ; and R 2 is C 1 -C 4 alkyl, preferably methyl or ethyl, most preferably ethyl.
DETAILED DESCRIPTION OF THE INVENTION
Referring to the five reaction steps under the "Summary of the Invention" section, this invention can be understood by considering the following detailed description.
The process of this invention is depicted by Reaction step 1. Reaction steps 2 through 5 are provided to illustrate process steps for the preparation of the 2,3,4-trisubstituted benzoyl chloride reaction product of Reaction step 5 which has known utility in the preparation of herbicidal compounds. Also, the intermediate reaction products of Reaction steps 1, 2, 3, and 4c are embodiments of this invention.
In Reaction step 1, a mole of the phenol is reacted with a mole of the Lewis acid to form a first complex. Using aluminum chloride as the Lewis acid, the first complex has the structural formula ##STR17## wherein R and R 2 are as defined.
Preferably, an additional mole or more of the Lewis acid is added to the reaction mixture but remains unreacted. Next, two moles of the acetyl halide is added to the reaction mixture. A mole of the acetyl halide reacts with a mole of the Lewis acid to form a second complex. When aluminum chloride is the Lewis acid, the complex has the structural formula ##STR18##
This second complex is an acylating agent and reacts with the first complex to add an acetyl group to the phenol para to the alkyl thio group as shown in Reaction step 1.
The second mole of the acetyl halide acylates the phenolic oxygen to form the acetoxy group ortho to the alkyl thio group on the ring as shown in Reaction step 1.
Thus in Reaction step 1, a mole of the phenol is mixed with a minimum of two moles of the acetyl halide, preferably acetyl chloride and a minimum of two moles of a Lewis acid, preferably aluminum chloride. The Lewis acid serves as a catalyst in the reaction. Preferably the reaction is run in an halogenated solvent such as ethylene dichloride, chloroform, or dichloromethane. The reaction can be run at a temperature of about 0° C. to about reflux temperature. Preferably, the reaction is run at about 20° C. to about 50° C.
At least one mole of the Lewis acid must be mixed with the phenol for a sufficient time to form the first complex of the Lewis acid and the hydroxyl group of the phenol before the acetyl halide is brought into contact with the phenol in the reaction mixture. The mixing can be done at room temperature, although lower and higher temperatures are also operative. If a mole of the phenol and at least one mole of the Lewis acid are mixed before contact with the acetyl halide, then the desired 2, 3, 4-trisubstituted acetophenone reaction product is obtained in high purity. Without this mixing, the acetyl substitution occurs para to the hydroxy group of the phenol, thus forming an undesired isomer of the desired 2, 3, 4-trisubstituted acetophenone. The preparation of the desired 2, 3, 4-trisubstituted acetophenone compound is surprising in view of the prior art. For example, U.S. Pat. No. 4,327,224 teaches that reaction of O-(methylthio) phenol with acetyl chloride and aluminum chloride in nitrobenzene affords the isomeric 4'-hydroxy-3'-(methylthio) acetophenone.
The desired reaction product can be recovered by conventional techniques such as by diluting the reaction mixture with additional solvent and pouring the diluted mixture into ice water. The aqueous phase is extracted with additional solvent and the combined organic phases are washed with dilute hydrochloric acid, dried and then concentrated in vacuo to give the desired acetophenone in high yield and in high purity.
Reaction step 2 is a simple hydrolysis step and can be carried out by any of the methods described by E. Haslam on p. 172 of "Protective Groups in Organic Chemistry", J. F. W. McOmie, Ed., 1973. Typically, the reaction is carried out by reacting a molar amount of the acetophenone of Reaction step 1 with at least a mole of a base such as sodium hydroxide optionally in a solvent such as water or methanol or a combination of the two with heating at about 50° C. to about 100° C. for about an hour. The resulting solution is cooled and acidified to pH 1 with hydrochloric acid. The resulting precipitated solids are collected by filtration to yield the desired product in high yields (greater than 95%).
For Reaction step 3, one mole of the substituted acetophenone reaction product of step 2 is reacted with an appropriate alkylating agent such as a 2-chloroethyl ethyl ether, 2-chloroethyl methyl ether, 2-chloroethyl methyl sulfide, 2-chloroethyl ethyl sulfide or C 1 -C 4 alkyl chloride along with a catalytic amount of potassium iodide and a molar excess of a base such as potassium carbonate. Alkyl iodides such as methyl iodide or ethyl iodide may also be used. In these cases, the catalytic potassium iodide is not needed and little or no heat is required. The reaction is run at 25° C. to 80° C. for 4 hours with agitation. The novel intermediate reaction product is recovered by conventional techniques.
For Reaction step 4, the novel intermediate compounds, 4-(C 1 -C 4 -alkylsulfonyl)-2,3-disubstituted benzoic acid compounds can be prepared by oxidizing a molar amount of the 4-(C 1 -C 4 -alkylthio)-2,3-disubstituted acetophenone prepared in Reaction step 3 with at least 5 moles of an oxidizing agent such as sodium hypochlorite in a suitable solvent such as dioxane by heating a solution of the reactants to 80° C. After an exothermic reaction, the mixture is cooled and acidified with hydrochloric acid. The desired intermediate which is a precipitate is recovered by filtration.
In Reaction step 5, the trisubstituted benzoic acid product of Reaction step 4 is converted to its acid chloride by reaction with oxalyl chloride according to the teaching of Reagents for Organic Synthesis, Vol. 1, L. F. Fieser and M. Fieser, pp. 767-769 (1967).
Reaction step 4a is run by reacting the substituted acetophenone with a mole excess of iodine in pyridine at a temperature of about 50° C. to about 100° C., followed by hydrolysis with sodium hydroxide in the manner described by L. C. King, J. Amer. Chem. Soc.. 66, 894 (1944). The desired intermediate compound is recovered by conventional techniques.
Reaction step 4b is run by reacting the described 2,3-disubstituted-4-(C 1 C 4 alkylthio) benzoic acid with a molar excess of an oxidizing agent such as sodium hypochlorite in a suitable solvent such as dioxane by heating the solution to a temperature between 50° C. and 100° C. After the reaction, the mixture is cooled and acidified with hydrochloric acid. The desired intermediate product, which is a precipitate, is recovered by filtration.
Reaction step 4c is run by reacting the substituted acetophenone from Reaction step 3 with at least 2 moles of an oxidizing agent such as sodium iodate, NaIO 4 , in an aqueous solvent at reflux temperature. The reaction product is recovered by conventional techniques.
Reaction step 4d is run by reacting the substituted acetophenone from Reaction step 4c with at least three moles of an oxidizing agent such as sodium hypochlorite in a suitable solvent such as dioxane by heating the solution to a temperature between 50° C. and 100° C. After the reaction, the mixture is cooled and acidified with hydrochloric acid. The desired intermediate product, which is a precipitate, is recovered by filtration.
EXAMPLE I
3-acetoxy-4-(ethylthio) acetophenone ##STR19##
A mixture of 5.0 g of 2-(ethylthio)phenol and 10.6 g of aluminum chloride in 20 ml of dichloromethane was stirred at ambient temperature for 30 min. Acetyl chloride (5.7 ml) was added dropwise over 25 min. and the resulting solution stirred at ambient temperature for 1 hr. The reaction mixture was diluted with dichloromethane and poured into 100 ml of ice water. The aqueous phase was extracted with dichloromethane and the combined organic phases washed with dilute hydrochloric acid, dried, and concentrated in vacuo to afford 7.1 g (94% yield) of 3-acetoxy-4-(ethylthio)acetophenone.
EXAMPLE II
3-Hydroxy-4-(ethylthio)acetophenone ##STR20##
A solution of 7.0 g of 3-acetoxy-4-(ethylthio)acetophenone, 44 ml of 5% sodium hydroxide solution, and 10 ml of methanol was heated at 75° C. for 1 hr. The cooled solution was acidified to pH 1 with 3 molar (M) HCl, and the resulting solids collected by filtration to give 5.6 g (96% yield) of the desired product 3-hydroxy-4-(ethylthio)acetophenone, mp 108°-109° C.
EXAMPLE III
2-Chloro-3-acetoxy-4-(ethylthio)acetophenone
A mixture of 1.8 g of 2-chloro-6-(ethylthio)phenol and 3.1 g of aluminum chloride in 15 ml of 1,2-dichloroethane was stirred at ambient temperature for 30 minutes. Acetyl chloride (1.7 ml) was added dropwise over a 5 minute period and the resulting solution was heated at reflux for 1 hour. The reaction mixture was diluted with 1,2-dichloroethane and poured into 50 ml of ice water. The aqueous phase was extracted with 1,2-dichloroethane and the combined organic layers were washed with dilute hydrochloric acid, dried, and concentrated in vacuo to afford 1.1 g (50% yield) of 3-acetoxy-2-chloro-4-(ethylthio)acetophenone.
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A process for the preparation of 2-(hydrogen, halogen or lower alkyl)-3-(hydroxy, C 1 -C 4 alkoxy, C 1 -C 4 haloalkoxy, --OCH 2 CH 2 OCH 3 , --OCH 2 CH 2 OC 2 H 5 , --OCH 2 CH 2 SCH 3 or --OCH 2 CH 2 SC 2 H 5 )-4-(alkylthio or alkylsulfonyl)-acetophenones.
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FIELD OF INVENTION
This invention concerns the technical field of treatment of cellulose containing material for the manufacturing of nanocellulose (microfibrillated cellulose). Also disclosed is nanocellulose manufactured in accordance with said method and uses of said cellulose.
BACKGROUND
In WO2005080678 a method for the modification of lignocellulosic materials is disclosed. Cellulose fibres are treated with an aqueous electrolyte-containing solution of an amphoteric cellulose derivative for at least 5 minutes at a temperature of at least 50° C. The pH during the treatment is approximately 1.5-4.5 or higher than 11; or the concentration of the electrolyte is approximately 0.0001-0.05 M if the electrolyte has monovalent cations, or approximately 0.0002-0.1 M if the electrolyte has divalent cations. Further said document relates to products obtained by the above mentioned method and uses of said products for manufacturing paper with a high wet strength.
However nothing is mentioned in the above document about manufacturing of nanocellulose or similar.
In Wågberg et al (2008) the reaction between chloroacetic acid and lignocellulose fibres is described as a pre-treatment to ease delamination in a homogenizer in order to create nanocellulose or microfibrillar cellulose. However, attachment of carboxymethylcellulose polymers to the lignocellulosic fibres is not described.
Through U.S. Pat. No. 4,341,807 further a method for manufacturing a microfibrillated cellulose or nanocellulose is disclosed by using homogenization. A problem when manufacturing nanocellulose from pulp is however the clogging of the homogenizer, when the pulp is pumped through high pressure fluidizers/homogenizers. Another problem is the excessive energy consumption during homogenization, unless the pulp before refining is subjected to some type of physiochemical pretreatment. Thus there is a need for a process wherein the clogging problem and the excessive energy consumption can be alleviated and/or avoided.
SUMMARY OF THE INVENTION
The present invention solves the above problem by providing according to a first aspect a method for providing a nanocellulose involving modifying cellulose fibers wherein the method comprises the following steps:
i) treating cellulose fibers for at least 5 minutes with an aqueous electrolyte-containing solution of an amphoteric carboxymethyl cellulose (amphoteric CMC) or a derivative thereof, preferably a low molecular amphoteric CMC or a CMC derivative thereof, whereby the temperature during the treatment is at least 50° C., and at least one of the following conditions apply:
A) the pH of the aqueous solution during the treatment lies in the interval of approximately 1.5-4.5, preferably in the region 2-4; or B) the pH of the aqueous solution during the treatment is higher than approximately 11; or C) the concentration of the electrolyte in the aqueous solution lies in the interval of approximately 0.0001-0.5 M, preferably approximately 0.001-0.4 M, if the electrolyte has monovalent cations (such as Na 2 SO 4 ), or in the range of approximately 0.0001-0.1 M, preferably approximately 0.0005-0.05 M, if the electrolyte has divalent cations (such as CaCl 2 ),
ii) adjusting the pH by using a basic and/or an acidic liquid into a pH range of from about 5 to about 13, preferably the pH is adjusted to a pH from about 6 to about 12, and
iii) treating said material in a mechanical comminution device, thus providing said nanocellulose.
This invention thereby involves attachment of amphoteric CMC polymers to lignocellulosic fibres as a pre-treatment before homogenization with the purpose of manufacturing nanocellulose. The attachment of amphoteric CMC polymers has proven to have several benefits, as outlined below.
The attachment of amphoteric CMC polymers decreases the energy consumption considerably and makes it possible to avoid clogging problems. Furthermore, it increases the anionic charge density of the fibres, which facilitates the delamination and, furthermore, enables delamination at much lower charge densities than if the charges would have been introduced by for instance any carboxymethylation reaction. Moreover, the CMC attachment process is aqueous based, which is beneficial since no other solvents than water is needed.
By using amphoteric CMC polymers, the attachment is easier and the attachment degree is increased as compared to anionic CMC.
Condition C is preferably combined with either of conditions A or B in step i), when applicable. The treated cellulose fibers may also after step i) be washed first with an acidic liquid and thereupon an essentially neutral liquid, preferably water.
The present invention also provides, according to a second aspect, a modified lignocellulosic material (nanocellulose) obtained by the method according to the first aspect. The attached amount of amphoteric CMC to lignocellulosic fibres is in the interval of from 5 to 250 milligram amphoteric CMC/gram dry fibre, preferably from 7 to 200 milligram amphoteric CMC/gram dry fibre and more preferably from 10 to 150 milligram amphoteric CMC/gram dry fibre. The attachment of amphoteric CMC as described herein advantageously enables an aqueous pre-treatment process for the manufacture of nanocellulose with less energy consumption and without the risk of clogging. This effect is attained by attachment of relatively small amounts of amphoteric CMC which results in lower charge densities than if a carboxymethylation reaction would have been used. Naturally, the anionic charge density of the amphoteric CMC used in the method influences the amount of CMC needed. CMC of high anionic charge density lowers the amount of CMC needed.
The present invention also provides according to a third aspect use of the lignocellulosic material (nanocellulose) of the second aspect in cosmetic products, pharmaceutical products, food products, paper products, composite materials, coatings, hygiene/absorbent products, films, emulsion/dispersing agents, drilling muds and to enhance the reactivity of cellulose in the manufacture of regenerated cellulose or cellulose derivatives or in rheology modifiers.
DETAILED DESCRIPTION OF THE INVENTION
It is intended throughout the present description that the expression “amphoteric cellulose derivative” embraces any cellulose derivative comprising simultaneously both cationic and anionic moieties. Further said amphoteric cellulose derivative is preferably an amphoteric cellulose derivative which still is net, negatively charged, but comprises a less amount of cationically active groups. Still further preferred said cellulose derivative is an amphoteric CMC (CMC=carboxymethyl cellulose) derivative, especially preferred is an amphoteric CMC derivative with a preferred anionic molar substitution degree between 0.3 and 1.2, i.e. D.S=0.3-1.2 and the viscosity may be approximately 25-8,000 mPa at a concentration of 4%.
This CMC derivative may further have been cationized in a, for the skilled person, well known manner to a substitution degree between 0.00001 and 1.0, preferably 0.00001 and 0.4. The cationization is preferably performed by the introduction of at least one ammonium function; most preferred a secondary, tertiary or quaternary ammonium function (or a mixture thereof) into the derivative.
It is intended throughout the present description that the expression “mechanical comminution device” means any device which may be suitable for providing a nanocellulose (a microfibrillated cellulose) as set out above, and said device may e.g. be a refiner, a fluidizer, a homogenizer or a microfluidizer.
According to a preferred embodiment of the first aspect of the present invention there is provided a method wherein said cellulose fibres (cellulose material) is present in the form of a pulp, which may be chemical pulp, mechanical pulp, thermomechanical pulp or chemi(thermo)mechanical pulp (CMP or CTMP). Said chemical pulp is preferably a sulphite pulp or a kraft pulp.
The pulp may consist of pulp from hardwood, softwood or both types. The pulp may e.g. contain a mixture of pine and spruce or a mixture of birch and spruce. The chemical pulps that may be used in the present invention include all types of chemical wood-based pulps, such as bleached, half-bleached and unbleached sulphite, kraft and soda pulps, and mixtures of these. The consistency of the pulp during manufacture of nanocellulose may be any consistency, ranging from low consistency through medium consistency to high consistency.
The preferred concentration of amphoteric cellulose derivative is approximately 0.02-4% w/w, calculated on the dry weight of the fiber material. A more preferred concentration is approximately 0.04-2% w/w, and the most preferred concentration of additive is approximately 0.08-1% w/w.
According to a preferred embodiment of the first aspect of the present invention there is provided a method wherein the cellulose fibres are treated for approximately 5-180 minutes; a preferred treatment (adsorption) period is approximately 10-120 min.
According to a preferred embodiment of the first aspect of the present invention there is provided a method wherein the temperature during the treatment is in excess of approximately 50° C., preferably at least approximately 100° C., and most preferred up to approximately 120° C. The method according to the invention may thus be carried out at a pressure in excess of atmospheric pressure. Suitable equipment and working conditions for this will be obvious for one skilled in the arts.
According to a preferred embodiment of the first aspect of the present invention there is provided a method wherein condition C applies together of either condition A or condition B in step i).
According to a preferred embodiment of the first aspect of the present invention there is provided a method wherein said cellulose fibers is contained in a pulp, preferably a sulphite pulp or a kraft pulp.
The preferred concentration of pulp is approximately 0.5-50%, a more preferred concentration interval is approximately 5-50%, and the most preferred concentration interval is approximately 10-30%. Such high concentration mixes are known to one skilled in the arts within the relevant technical field, and are suitable for use in association with the present invention.
Preferred features of each aspect of the invention are as for each of the other aspects mutatis mutandis. The prior art documents mentioned herein are incorporated to the fullest extent permitted by law. The invention is further described in the following examples in conjunction with the appended figures, which do not limit the scope of the invention in any way. Embodiments of the present invention are described in more detail with the aid of examples of embodiments and figures, the only purpose of which is to illustrate the invention and are in no way intended to limit its extent.
FIGURES
In the appended FIGS. 1-7 , resulting products after homogenisation are shown as set out in the examples part below. More specifically:
FIG. 1 shows Case C which gave rise to an MFC gel.
FIG. 2 shows Case D which gave rise to an MFC gel.
FIG. 3 shows Case E which gave rise to an MFC gel.
FIG. 4 shows Case F which gave rise to an MFC gel.
FIG. 5 shows Case H which gave rise to an MFC gel.
FIG. 6 shows Case K which did not give rise to an MFC gel.
FIG. 7 shows Case L which gave rise to an MFC gel.
EXAMPLES
Cases A-F
Pulp: Commercial Never Dried Bleached Sulphite Pulp (Domsjö ECO Bright, Domsjö Fabriker)
Procedure:
1. The never dried pulp was first dispersed in deionised water. Two liters of deionised water was added to 30 grams of pulp and was then dispersed with 10000 revolutions in a laboratory disintegrator in accordance to (ISO 5263-1:2004).
2. The pulp was then ion-exchanged into its hydrogen counter-ion form. Firstly, the HCl was added to the pulp to a concentration of 10 −2 M (pH is 2). The pH was held at 2 for 30 minutes. Then the pulp was washed with deionised water on a büchner funnel until the conductivity of the filtrate was below 5 μS/cm.
3. The pulp was then ion-exchanged into its sodium counter-ion form. Firstly, the NaHCO 3 was added to the pulp to a concentration of 10 −3 M and NaOH was then added to reach a pH of 9. The pH was held at 9 for 30 minutes. Then the pulp was washed with deionised water on a büchner funnel until the conductivity of the filtrate was below 5 μS/cm.
4. Amphoteric-CMC with an anionic degree of substitution of 0.64, cationic degree of substitution of 0.048 and an intrinsic viscosity of 2.0 was dissolved in deionised water.
5. The CMC-attachment was carried out in accordance to Laine et al. (Laine, J. et al. (2000) Nordic Pulp and Paper Research Journal 15(5), page 520-526). Conditions during attachment: pulp concentration=20 gram/liter; temperature=120° C.; treatment time=2 hours; CaCl 2 -concentration=0.05 M; water=deionised water. Different amounts of CMC was added for the different cases, A-F (Case A=0 mg CMC/g fibre, Case B=10 mg CMC/g fibre, Case C=20 mg CMC/g fibre, Case D=40 mg CMC/g fibre, Case E=80 mg CMC/g fibre, Case F=120 mg CMC/g fibre).
6. After the CMC-attachment treatment, the pulp was washed with deionised water on a büchner funnel until the conductivity of the filtrate was below 5 μS/cm.
7. The pulp was then ion-exchanged into its sodium counter-ion form as described above in step 2 and 3.
8. The pulps (2% concentration in deionised water) were then homogenised with one pass through a Microfluidizer M-110EH (Microfluidics Corp.) at an operating pressure of 1750 bar. The chambers that were used had an inner diameter of 200 μm and 100 μm.
Cases G-H
Pulp: Commercial never dried bleached sulphite dissolving pulp (Domsjö Dissolving plus, Domsjö Fabriker)
Procedure:
1. The never dried pulp was first dispersed in deionised water. Two liters of deionised water was added to 30 grams of pulp and was then dispersed with 10000 revolutions in a laboratory disintegrator in accordance to (ISO 5263-1:2004).
2. The pulp was then ion-exchanged into its hydrogen counter-ion form. Firstly, the HCl was added to the pulp to a concentration of 10 −2 M (pH is 2). The pH was held at 2 for 30 minutes. Then the pulp was washed with deionised water on a büchner funnel until the conductivity of the filtrate was below 5 μS/cm.
3. The pulp was then ion-exchanged into its sodium counter-ion form. Firstly, the NaHCO 3 was added to the pulp to a concentration of 10 −3 M and NaOH was then added to reach a pH of 9. The pH was held at 9 for 30 minutes. Then the pulp was washed with deionised water on a büchner funnel until the conductivity of the filtrate was below 5 μS/cm.
4. Amphoteric-CMC with an anionic degree of substitution of 0.64, cationic degree of substitution of 0.048 and an intrinsic viscosity of 2.0 was dissolved in deionised water.
5. The CMC-attachment was carried out in accordance to Laine et al. (Laine, J. et al. (2000) Nordic Pulp and Paper Research Journal 15(5), page 520-526). Conditions during attachment: pulp concentration=20 gram/liter; temperature=120° C.; treatment time=2 hours; CaCl 2 -concentration=0.05 M; water=deionised water. Different amounts of CMC was added for the different cases G-H (Case G=0 mg CMC/g fibre, Case H=80 mg CMC/g fibre).
6. After the CMC-attachment treatment, the pulp was washed with deionised water on a büchner funnel until the conductivity of the filtrate was below 5 μS/cm.
7. The pulp was then ion-exchanged into its sodium counter-ion form as described above in step 2 and 3.
8. The pulps (2% concentration in deionised water) were then homogenised with one pass through a Microfluidizer M-110EH (Microfluidics Corp.) at an operating pressure of 1750 bar. The chambers that were used had an inner diameter of 200 μm and 100 μm.
Case I
Pulp: Commercial Never Dried Bleached Sulphite Pulp (Domsjö ECO Bright, Domsjö Fabriker)
Procedure:
1. The never dried pulp was first dispersed in deionised water. Two liters of deionised water was added to 30 grams of pulp and was then dispersed with 10000 revolutions in a laboratory disintegrator in accordance to (ISO 5263-1:2004).
2. The pulp was then ion-exchanged into its hydrogen counter-ion form. Firstly, the HCl was added to the pulp to a concentration of 10 −2 M (pH is 2). The pH was held at 2 for 30 minutes. Then the pulp was washed with deionised water on a büchner funnel until the conductivity of the filtrate was below 5 μS/cm.
3. The pulp was then ion-exchanged into its sodium counter-ion form. Firstly, the NaHCO 3 was added to the pulp to a concentration of 10 −3 M and NaOH was then added to reach a pH of 9. The pH was held at 9 for 30 minutes. Then the pulp was washed with deionised water on a büchner funnel until the conductivity of the filtrate was below 5 μS/cm.
4. Amphoteric-CMC with an anionic degree of substitution of 0.65, cationic degree of substitution of 0.048 and an intrinsic viscosity of 2.0 was dissolved in tap water.
5. The CMC-attachment was carried out in accordance to Laine et al. (Laine, J. et al. (2000) Nordic Pulp and Paper Research Journal 15(5), page 520-526). Conditions during attachment: pulp concentration=20 gram/liter; temperature=room temperature (around 20° C.); treatment time=2 hours; water=tap water; CMC addition=10 mg CMC/g fibre, no addition of extra electrolytes.
6. After the CMC-attachment treatment, the pulp was washed with deionised water on a büchner funnel until the conductivity of the filtrate was below 5 μS/cm.
7. The pulp was then ion-exchanged into its sodium counter-ion form as described above in step 2 and 3.
8. The pulps (2% concentration in deionised water) were then homogenised with one pass through a Microfluidizer M-110EH (Microfluidics Corp.) at an operating pressure of 1700 bar. The chambers that were used had an inner diameter of 200 μm and 100 μm.
Case J
Pulp: Commercial Never Dried Bleached Sulphite Pulp (Domsjö ECO Bright, Domsjö Fabriker)
Procedure:
1. The never dried pulp was first dispersed in deionised water. Two liters of deionised water was added to 30 grams of pulp and was then dispersed with 10000 revolutions in a laboratory disintegrator in accordance to (ISO 5263-1:2004).
2. The pulp was then ion-exchanged into its hydrogen counter-ion form. Firstly, the HCl was added to the pulp to a concentration of 10 −2 M (pH is 2). The pH was held at 2 for 30 minutes. Then the pulp was washed with deionised water on a büchner funnel until the conductivity of the filtrate was below 5 μS/cm.
3. The pulp was then ion-exchanged into its sodium counter-ion form. Firstly, the NaHCO 3 was added to the pulp to a concentration of 10 −3 M and NaOH was then added to reach a pH of 9. The pH was held at 9 for 30 minutes. Then the pulp was washed with deionised water on a büchner funnel until the conductivity of the filtrate was below 5 μS/cm.
4. Anionic-CMC with an anionic degree of substitution of 0.57 and an intrinsic viscosity of 1.4 was dissolved in deionised water.
5. The CMC-attachment was carried out in accordance to Laine et al. (Laine, J. et al. (2000) Nordic Pulp and Paper Research Journal 15(5), page 520-526). Conditions during attachment: pulp concentration=20 gram/liter; temperature=120° C.; treatment time=2 hours; CaCl 2 -concentration=0.05 M; water=deionised water; CMC-dosage=80 mg CMC/g fibre.
6. After the CMC-attachment treatment, the pulp was washed with deionised water on a büchner funnel until the conductivity of the filtrate was below 5 μS/cm.
7. The pulp was then ion-exchanged into its sodium counter-ion form as described above in step 2 and 3.
8. The pulps (2% concentration in deionised water) were then homogenised with one pass through a Microfluidizer M-110EH (Microfluidics Corp.) at an operating pressure of 1750 bar. The chambers that were used had an inner diameter of 200 μm and 100 μm.
Case K
Pulp: Commercial never dried bleached sulphite dissolving pulp (Domsjö Dissolving plus, Domsjö Fabriker)
Procedure:
1. The never dried pulp was first dispersed in deionised water. Two liters of deionised water was added to 30 grams of pulp and was then dispersed with 10000 revolutions in a laboratory disintegrator in accordance to (ISO 5263-1:2004).
2. The pulp was then ion-exchanged into its hydrogen counter-ion form. Firstly, the HCl was added to the pulp to a concentration of 10 −2 M (pH is 2). The pH was held at 2 for 30 minutes. Then the pulp was washed with deionised water on a büchner funnel until the conductivity of the filtrate was below 5 μS/cm.
3. The pulp was then ion-exchanged into its sodium counter-ion form. Firstly, the NaHCO 3 was added to the pulp to a concentration of 10 −3 M and NaOH was then added to reach a pH of 9. The pH was held at 9 for 30 minutes. Then the pulp was washed with deionised water on a büchner funnel until the conductivity of the filtrate was below 5 μS/cm.
4. Anionic-CMC with an anionic degree of substitution of 0.57 and an intrinsic viscosity of 1.4 was dissolved in deionised water.
5. The CMC-attachment was carried out in accordance to Laine et al. (Laine, J. et al. (2000) Nordic Pulp and Paper Research Journal 15(5), page 520-526). Conditions during attachment: pulp concentration=20 gram/liter; temperature=120° C.; treatment time=2 hours; CaCl 2 -concentration=0.05 M; water=deionised water; CMC-dosage=80 mg CMC/g fibre.
6. After the CMC-attachment treatment, the pulp was washed with deionised water on a büchner funnel until the conductivity of the filtrate was below 5 μS/cm.
7. The pulp was then ion-exchanged into its sodium counter-ion form as described above in step 2 and 3.
8. The pulps (2% concentration in deionised water) were then homogenised with one pass through a Microfluidizer M-110EH (Microfluidics Corp.) at an operating pressure of 1750 bar. The chambers that were used had an inner diameter of 200 μm and 100 μm.
Case L
Pulp: Commercial Never Dried Bleached Sulphite Pulp (Domsjö ECO Bright, Domsjö Fabriker)
Procedure:
1. The never dried pulp was first dispersed in deionised water. Two liters of deionised water was added to 30 grams of pulp and was then dispersed with 10000 revolutions in a laboratory disintegrator in accordance to (ISO 5263-1:2004).
2. The pulp was then ion-exchanged into its hydrogen counter-ion form. Firstly, the HCl was added to the pulp to a concentration of 10 −2 M (pH is 2). The pH was held at 2 for 30 minutes. Then the pulp was washed with deionised water on a büchner funnel until the conductivity of the filtrate was below 5 μS/cm.
3. The pulp was then ion-exchanged into its sodium counter-ion form. Firstly, the NaHCO 3 was added to the pulp to a concentration of 10 −3 M and NaOH was then added to reach a pH of 9. The pH was held at 9 for 30 minutes. Then the pulp was washed with deionised water on a büchner funnel until the conductivity of the filtrate was below 5 μS/cm.
4. Anionic-CMC with an anionic degree of substitution of 0.4 and an intrinsic viscosity of 15 was dissolved in deionised water.
5. The CMC-attachment was carried out in accordance to Laine et al. (Laine, J. et al. (2000) Nordic Pulp and Paper Research Journal 15(5), page 520-526). Conditions during attachment: pulp concentration=20 gram/liter; temperature=120° C.; treatment time=2 hours; CaCl 2 -concentration=0.05 M; water=deionised water; CMC-dosage=80 mg CMC/g fibre.
6. After the CMC-attachment treatment, the pulp was washed with deionised water on a büchner funnel until the conductivity of the filtrate was below 5 μS/cm.
7. The pulp was then ion-exchanged into its sodium counter-ion form as described above in step 2 and 3.
8. The pulps (2.6% concentration in deionised water) were then homogenised with one pass through a Microfluidizer M-110EH (Microfluidics Corp.) at an operating pressure of 1750 bar. The chambers that were used had an inner diameter of 200 μm and 100 μm.
Analysis
Conductometric Titration
The attached amount of anionic CMC on the fibres was determined by conductometric titration. The conductometric titration measures the total amounts of anionic groups, e.g. carboxyl acid groups, in the pulps. Prior to the titration, the pulp was washed to different counter-ion form as follows.
1. First the pulp was set to its hydrogen counter-ion form. A sample containing 2 g of dry pulp was dispersed in 1000 ml of deionised water and then 0.01 M HCl was added, fixing pH to 2. The excessive HCl was washed away after 30 minutes with deionised water on a büchner funnel until the conductivity was below 5 μS/cm. 2. Secondly, the pulp was set to its sodium counter-ion form. The pulp was dispersed in deionised water and then 0.001 M NaHCO 3 was added, pH was set to 9 using NaOH. After 30 more minutes the excessive NaOH and the NaHCO 3 were washed away with deionised water on a büchner funnel until the conductivity was below 5 μS/cm. 3. After this, the sample was once more set to its hydrogen counter ion form (see step 1) and washed to a conductivity below 5 μS/cm. 4. Finally, the total charge density of the pulps were determined with conductometric titration according to the procedure described by Katz et al. “The determination of strong and acidic groups in sulfite pulps”, svensk papperstidning no. 6/1984, page R48-R53.
The amount of attached CMC was evaluated by comparing the result from the anionic CMC pulps with the result from reference pulp, the amount of attached CMC could be determined.
Nitrogen Analysis
In order to evaluate the attached amount of amphoteric CMC, the nitrogen content in the pulps were measured. This was done since the amphoteric CMC's cationic groups contained nitrogen. The apparatus used was an Antek 7000 (Antek Instruments, Inc.) and the method was Pyro-chemiluminescence (combustion temperature=1050° C.). Before the actual measurements, a calibration curve was made with the amphoteric CMC in order to know how much nitrogen was present per mg CMC.
Intrinsic Viscosity of CMC
The intrinsic viscosity of the CMCs was measured in deionised water with 0.1 M NaCl at a temperature of 25° C.
Results
CMC
Added
Total
Attached
Results
Intrinsic
amount
Grafting/
charge
amount
in an
Anionic
Cationic
viscosity
of CMC
Temp.
density
of CMC
MFC
Case
Pulp
CMC
DS
DS
[dl/g]
[mg/g]
[° C.]
[μeq./g]
[mg/g]
Clogging
gel?
A
Sulphite
—
—
—
—
0
No
50.2
0
Yes
No
B
Sulphite
Amphoteric
0.65
0.048
2.0
10
Yes/120
60.9
10.7
Yes
No
C
Sulphite
Amphoteric
0.65
0.048
2.0
20
Yes/120
89.3
19.5
No
Yes
D
Sulphite
Amphoteric
0.65
0.048
2.0
40
Yes/120
124.7
40.5
No
Yes
E
Sulphite
Amphoteric
0.65
0.048
2.0
80
Yes/120
173.4
80.4
No
Yes
F
Sulphite
Amphoteric
0.65
0.048
2.0
120
Yes/120
231.3
113.4
No
Yes
G
Dissolving
—
—
—
—
0
No
30.3
0
Yes
No
H
Dissolving
Amphoteric
0.65
0.048
2.0
80
Yes/120
164.5
80.2
No
Yes
I
Sulphite
Amphoteric
0.65
0.048
2.0
10
Yes/20
50.9
0
Yes
No
J
Sulphite
Anionic
0.57
—
1.4
80
Yes/120
115.3
23.7
Yes
No
K
Dissolving
Anionic
0.57
—
1.4
80
Yes/120
107.8
28.2
No
No
L
Sulphite
Anionic
0.4
—
15
80
Yes/120
177.3
61.6
No
Yes
As can be seen in the table, it was not possible to homogenise the pulps without any CMC attachment due to clogging (Cases A and G). With the aid of amphoteric CMC it was possible to homogenise the pulp without clogging when the attachment level was above 23.6 mg/g (Cases C-F and H) and this resulted in an MFC gel. Lower attachment levels resulted in clogging (Case B). If the temperature during the CMC-attachment procedure was lowered to room temperature (Case I), no CMC was attached to the pulp and as a result it was not possible to homogenise due to clogging. In Cases J and K, anionic CMC was attached to the pulps. However, since the CMC was anionic the attachment level was lower and this made it impossible to make MFC. In Case J, sulphite pulp was used and this sample was possible to homogenise but did not result in a MFC gel. The dissolving pulp in Case K was not possible to homogenise due to clogging. All conditions in Case L, were the same as in Case J, but another anionic CMC was used instead. This CMC was easier to attach and as a result the attachment level was as high as 61.6 mg/g. Since the amount of CMC was higher it was possible to homogenise this sample and thereby produce an MFC gel. However, to reach this level three times more CMC was needed than if amphoteric CMC was used (compare with Case C). In the appended FIGS. 1-7 , the resulting products after homogenisation are shown.
Various embodiments of the present invention have been described above but a person skilled in the art realizes further minor alterations, which would fall into the scope of the present invention. The breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents. For example, any of the above-noted methods can be combined with other known methods. Other aspects, advantages and modifications within the scope of the invention will be apparent to those skilled in the art to which the invention pertains.
LIST OF DOCUMENTS APPEARING IN THE DESCRIPTION
WO2005080678
U.S. Pat. No. 4,341,807
Laine et al. (Laine, J. et al. (2000) Nordic Pulp and Paper Research Journal 15(5), page 520-526) and
Katz et al. “The determination of strong and acidic groups in sulfite pulps”, svensk papperstidning no. 6/1984, page R48-R53.
Wågberg et al. “The Build-Up of Polyelectrolyte Multilayers of Microfibrillated Cellulose and Cationic Polyelectrolytes”. Langmuir (2008), 24(3), 784-795.
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A method for the manufacturing of nanocellulose. The method includes a first modification of the cellulose material, where the cellulose fibers are treated with an aqueous electrolyte-containing solution of an amphoteric cellulose derivative. The modification is followed by a mechanical treatment. By using this method for manufacturing nanocellulose, clogging of the mechanical apparatus is avoided. Also the nanocellulose is manufactured in accordance with the method and uses of the cellulose.
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FIELD
[0001] The present invention relates to a multiplex-driven, vertically aligned liquid crystal display element.
BRIEF DESCRIPTION OF DROWINGS
[0002] FIG. 1 depicts a cross section of an example of vertically aligned liquid crystal display element according to embodiments.
[0003] FIGS. 2A to 2C are plan views illustrating the segment electrode arrangement pattern, common electrode arrangement pattern, and some pixels resulting from their overlap in the liquid crystal display element described in an embodiment sample Sa 1 .
[0004] FIGS. 3A to 3C are plan views illustrating the segment electrode arrangement pattern, common electrode arrangement pattern, and some pixels resulting from their overlap in the liquid crystal display element described in an embodiment sample Sat.
[0005] FIGS. 4A to 4C are plan views illustrating the segment electrode arrangement pattern, common electrode arrangement pattern, and some pixels resulting from their overlap in the liquid crystal display element described in an embodiment sample Sa 3 .
[0006] FIGS. 5A to 5C are plan views illustrating the segment electrode arrangement pattern, common electrode arrangement pattern, and some pixels resulting from their overlap in the liquid crystal display element described in an embodiment sample Sa 4 .
[0007] FIG. 6A is a graph illustrating the dependence of transmittance characteristics on the observation angle (−60° to)+60° for the samples Sa 1 to Sa 4 and a reference sample Ref.
[0008] FIG. 6B is a table that shows x,y chromaticity observations according to the XYZ colorimetric system at an observation angle of 0°, 40° or 60° for the samples Sa 1 to Sa 4 and the reference sample Ref.
[0009] FIGS. 7A to 7C are plan views illustrating the segment electrode arrangement patterns used in samples Sa 5 to Sa 7 .
[0010] FIG. 8A is a graph illustrating the dependence of transmittance characteristics on the observation angle (−60° to)+60° for the samples Sa 5 to Sa 7 and a reference sample Ref.
[0011] FIG. 8B is a table that shows x,y chromaticity observations according to the XYZ colorimetric system at an observation angle of 0°, 40° or 60° for the samples Sa 5 to Sa 7 and the reference sample Ref.
[0012] FIGS. 9A and 9B are a schematic figure illustrating the electric field around the edge of an opening under an applied voltage and a front perspective view schematically illustrating oriented molecules at the thickness-direction center of a liquid crystal layer.
[0013] FIGS. 10A and 10B are a schematic figure illustrating the electric field around the edge of a pixel under an applied voltage and a front perspective view schematically illustrating oriented molecules at the thickness-direction center of a liquid crystal layer.
[0014] FIG. 11 shows a cross section figure of an example of conventional vertically aligned liquid crystal display.
[0015] FIGS. 12A and 12B illustrate schematic figures of a model of conventional liquid crystal display element used in the simulation analysis.
[0016] FIG. 13A shows the dependence of transmittance characteristics on the observation angle (−60° to)+60° in the first to third conventional liquid crystal display elements.
[0017] FIG. 13B is a table that shows x,y chromaticity observations according to the XYZ colorimetric system at an observation angle of ±50° or ±60° for the first to third conventional liquid crystal display elements.
BACKGROUND
[0018] FIG. 11 shows a cross section figure of an example of conventional vertically aligned liquid crystal display. This liquid crystal display element comprises a liquid crystal cell 9 , viewing angle compensation plates 3 a and 3 b provided on both sides of the liquid crystal cell 9 , and polarizing plates 10 and 20 that sandwich the liquid crystal cell 9 and the viewing angle compensation plates 3 a and 3 b . The polarizing plates 10 and 20 are set up in a crossed Nicols arrangement. The liquid crystal cell 9 comprises a liquid crystal layer 30 with a negative dielectric constant anisotropy, Δ∈, and lower transparent substrates 4 and 5 that sandwich the liquid crystal layer 30 . The upper and lower substrates 4 and 5 are provided with upper and lower transparent electrodes 11 and 15 , respectively, and vertical alignment films 12 and 14 that are formed to cover the upper and lower electrodes 11 and 15 and are treated by alignment process, respectively.
[0019] A display area 18 is defined in a portion where the transparent electrodes 11 and 15 overlap each other, with the liquid crystal layer 30 sandwiched between them. In the zero of applied voltage, the liquid crystal molecules in the liquid crystal layer 30 are oriented nearly vertically to the transparent substrates 4 and 5 , and the refractive index is nearly isotropic in in-plane directions to produce a dark state in the display area 18 when combined with the polarizing plates 10 and 20 in a crossed Nicols arrangement. When a voltage equal to or higher than the threshold voltage of the liquid crystal layer 30 is applied between the transparent electrodes 11 and 15 , the liquid crystal molecules in the liquid crystal layer 30 are tilted to the transparent substrates 4 and 5 , and the refractive index of liquid crystal layer 30 becomes anisotropic in in-plane, allowing the incident light to pass through the polarizing plates 10 and 20 in a crossed Nicols arrangement to produce a light state in the display area 18 .
[0020] There are some different types of electrode arrangement used to drive liquid crystal display elements, such as segment electrode arrangement (including seven segment display and fixed pattern display) and simple matrix type dot matrix electrode. In the case of a segment electrode arrangement, a segment electrode to define display areas is formed on one of the transparent substrates, while a common electrode of a predefined shape to cover the display areas (or the segmented electrode) is formed on the other transparent substrate. In the case of a simple matrix type dot matrix electrode, characters and numbers are displayed by applying a voltage selectively to appropriate intersections (pixels) between the scanning electrodes formed on one transparent substrate and the signal electrodes formed on the other transparent substrate.
[0021] It is generally known that these liquid crystal display elements have good legibility when seen from the normal direction to the substrate, but the transmittance and color may change when seen from an oblique direction from the normal to the substrate.
[0022] Japanese Patent No. 2047880 discloses a liquid crystal display element comprising a viewing angle compensation plate having a negative uniaxial optical anisotropy (negative uniaxial film) or a viewing angle compensation plate having a negative biaxial optical anisotropy (negative biaxial film) provided between a polarizing plate and a substrate designed for conventional vertically aligned liquid crystal display elements.
[0023] Japanese Patents No. 3834304 and No. 2947350 disclose a multi-domain vertically aligned liquid crystal element in which the liquid crystal molecules constituting the liquid crystal layer are oriented in two or more directions.
[0024] Japanese Patent No. 2872628 and No. 4614200 disclose an alignment method to produce a nearly vertical alignment.
SUMMARY
[0025] The object of the invention is to provide a vertically aligned liquid crystal display element having high display performance.
[0026] According to an aspect of the invention,
[0027] A simple matrix type dot-matrix liquid crystal display element comprising:
[0028] a first and a second transparent substrate disposed opposite to each other;
[0029] two or more first transparent electrodes that are disposed on a face of the first transparent substrate, said face facing to the other substrate, and that are extended as a whole in a first direction;
[0030] two or more second transparent electrodes that are disposed on a face of the second transparent substrate, said face facing to the other substrate, and that are extended as a whole in the perpendicular direction to said first direction;
[0031] a first and a second vertical alignment film disposed on the opposed (i.e., inner) side of the first and the second transparent substrate to cover the first and the second transparent electrodes, respectively;
[0032] a liquid crystal layer disposed between the opposed faces of the first and the second transparent substrate and having a negative dielectric constant anisotropy and a retardation of more than 450 nm;
[0033] a first and a second viewing angle compensation plate disposed on the unopposed faces of the first and the second transparent substrate, respectively; and
[0034] a first and a second polarizing plate disposed in a nearly crossed Nicols arrangement outside the first and the second viewing angle compensation plate, respectively;
[0000] wherein:
[0035] at least either of the first and the second vertical alignment film is treated by an alignment process in a second direction that contains a component of the first direction;
[0036] each pixel formed by the first and the second electrode overlapping each other with said liquid crystal layer sandwiched in between have two or more sides that intersect with perpendiculars to said second direction; and
[0037] in those portions that correspond to said pixels in said first transparent electrode, openings extending in said direction that contains a component of the first direction are aligned.
DESCRIPTION OF EMBODIMENTS
[0038] The present inventor carried out simulation analysis of conventional vertically aligned liquid crystal display elements to study the dependence of the transmittance characteristics and color on the observation direction. LCD MASTER 6.4 supplied by Shintech, Inc., was used for the simulation analysis.
[0039] FIGS. 12A and 12B illustrate schematic figures of a panel configuration of conventional liquid crystal display element used in the simulation analysis.
[0040] The first conventional liquid crystal display element depicted in FIG. 12A comprises a liquid crystal cell 9 , a viewing angle compensation plate 3 located on one side of the liquid crystal cell 9 , and polarizing plates 10 and 20 that sandwich the liquid crystal cell 9 and the viewing angle compensation plate 3 . The viewing angle compensation plate 3 is a negative biaxial film with an in-plane retardation of 50 nm and a thickness-direction retardation of 440 nm. The polarizing plates 10 and 20 are set up in a crossed Nicols arrangement. The cross sectional view of the liquid crystal cell 9 is depicted in FIG. 11 and comprises a liquid crystal layer 30 with a Δ∈ of negative and upper and lower transparent substrates 4 and 5 that sandwich the liquid crystal layer 30 . The upper and lower substrates 4 and 5 are provided with upper and lower transparent electrodes, respectively, and vertical alignment films treated by alignment process that are formed to cover the upper and lower electrodes, respectively. The upper and lower electrodes and the vertical alignment films expediently aren't depicted in FIG. 12A . The liquid crystal layer 30 has a birefringence, Δn, of about 0.15 and a thickness, d, of about 4 μm. Accordingly, the retardation, Δnd, of the liquid crystal layer 30 is about 600 nm. The liquid crystal molecules constituting the liquid crystal layer 30 have a pretilt angle (angle of inclination of the long axis of the liquid crystal molecules to the substrate plane) of 89.5°.
[0041] The upper and lower polarizing plates 10 and 20 each consist of a polarizing layer 1 located on a TAC (triacetyl cellulose) base film 2 . Though not depicted, a surface protective film of TAC is provided on the polarizing layer 1 . The polarizing plate's TAC layer has an in-plane retardation of 3 nm, and its slow axis is parallel to the absorption axis of the polarizing plate. The polarizing plate's TAC layer has a thickness-direction retardation of 50 nm.
[0042] In the coordinate system given in FIG. 12A , the rubbing direction, Rub, for the upper substrate 4 is 270°, while the rubbing direction, Rub, for the lower substrate 5 is 90°. The azimuthal director direction in the liquid crystal layer 30 (azimuthal direction of liquid crystal molecule orientation at the thickness-direction center of the liquid crystal layer) is 90°. The absorption axis, ab, of the polarizing layer 1 and the in-plane slow axis in the TAC base film 2 , TACsI, in the upper polarizing plate 10 are in the direction of 135°, and those in the lower polarizing plate 20 are in the direction of 45°. The in-plane slow axis, Bsl, in the negative biaxial film 3 is nearly perpendicular to the absorption axis in the adjacent polarizing plate and it is in the direction of 135°.
[0043] In the second conventional liquid crystal display element depicted in FIG. 12B , the viewing angle compensation plate 3 a provided between the lower substrate 5 and the lower polarizing plate 20 is a negative biaxial film, and the viewing angle compensation plate 3 b provided between the upper substrate 4 and the upper polarizing plate 10 is a negative biaxial film. Otherwise, the element is the same as the first conventional liquid crystal display element.
[0044] In the coordinate system FIG. 12B , the in-plane slow axis, Bsl 1 , in the negative biaxial film 3 a is nearly perpendicular to the absorption axis, ab, of the polarizing layer 1 in the adjacent polarizing plate 20 and it is in the direction of 135°. The in-plane slow axis, Bsl 2 , in the negative biaxial film 3 b is nearly perpendicular to the absorption axis, ab, of the polarizing layer 1 in the adjacent polarizing plate 10 and it is in the direction of 45°. In both negative biaxial films 3 a and 3 b , the in-plane retardation is 25 nm and the thickness-direction retardation is 220 nm.
[0045] In a third conventional liquid crystal display element, the viewing angle compensation plate 3 a as shown in FIG. 12B is a negative biaxial film with an in-plane retardation of 50 nm and a thickness-direction retardation of 220 nm, and the viewing angle compensation plate 3 b is a negative uniaxial film (C plate) with an in-plane retardation of 0 nm and a thickness-direction retardation of 220 nm. Otherwise, the element is the same as the second conventional liquid crystal display element.
[0046] For these first to third conventional liquid crystal display elements, the normal direction to the substrate plane is defined as 0° (a front direction or a normal direction), and the direction of 180° (9 o'clock) or 0° (3 o'clock) in the coordinate system in FIGS. 12A and 12B is defined as the left or right direction. Described below is the dependence of the transmittance characteristics and color shift on the inclination angle (polar angle) in the left or right direction (observation angle) of the first to third conventional liquid crystal display elements.
[0047] FIG. 13A shows the dependence of transmittance characteristics on the observation angle (−60° to)+60° in the first to third conventional liquid crystal display elements. The horizontal axis of the graph represents the observation angle in units of ° (degrees), and the vertical axis represents the transmittance in a light state in units of %. The curves α, β and γ indicate the transmittance characteristics of the first conventional liquid crystal display element (negative biaxial film on one side), the transmittance characteristics of the second conventional liquid crystal display element (negative biaxial film on both sides), and the transmittance characteristics of the third conventional liquid crystal display element (negative biaxial film on one side, C plate on the other side), respectively. The drive conditions include multiplex driving at 1/16 duty, ⅕ bias and a voltage to produce the maximum contrast. A standard light source D65 is used as the light source.
[0048] This graph indicates asymmetry in the dependence of the transmittance characteristics on the observation angle in the case of the first conventional liquid crystal display element. For the second conventional liquid crystal display element, the symmetry in the transmittance characteristics is observed, but a decrease in transmittance at large observation angles is achieved. For the third conventional liquid crystal display element, a decrease in transmittance at large observation angles is observed as in the case of the second conventional liquid crystal display element, and asymmetry in the transmittance characteristics is achieved.
[0049] FIG. 13B is a table that shows x,y chromaticity observations according to the XYZ colorimetric system at an observation angle of ±50° or ±60° for the first to third conventional liquid crystal display elements. It is clear from this table that in the case of the second and third conventional liquid crystal display elements, the hue is nearly yellow at an observation angle of ±50° but changes into the range of violet to blue as the observation angle shifts to ±60°.
[0050] From these results of simulation analysis, it is evidence that when a viewing angle compensation plate is provided on both sides of the liquid crystal cell as in the case of the second and third conventional liquid crystal display elements, the transmittance considerably decreases and large changes in hue is observed at large observation angles. Such degradation in viewing angle characteristics should preferably be minimized. An investigation by the inventor showed that significant degradation in the viewing angle characteristics was observed when the retardation of the liquid crystal layer became larger than about 450 nm. The inventor carried out study to improve the viewing angle characteristics of a vertically aligned liquid crystal display element comprising a viewing angle compensation plate provided on both sides of the liquid crystal cell.
[0051] FIG. 1 depicts a cross section of an example of vertically aligned liquid crystal display element according to embodiments. This liquid crystal display element comprises a liquid crystal cell 9 , viewing angle compensation plates 3 a and 3 b provided on both sides of the liquid crystal cell, and polarizing plates 10 and 20 that sandwich the liquid crystal cell 9 and the viewing angle compensation plates 3 a and 3 b . The viewing angle compensation plates 3 a and 3 b are negative biaxial films. The polarizing plates 10 and 20 are set up in a crossed Nicols arrangement. The liquid crystal cell 9 comprises a liquid crystal layer 30 with a Δ∈ of negative and upper and lower transparent substrates 4 and 5 that sandwich the liquid crystal layer 30 . The upper and lower substrates 4 and 5 are provided with upper and lower transparent electrodes 13 and 15 , respectively, and vertical alignment films 12 and 14 treated by alignment process that are formed to cover the upper and lower electrodes 13 and 15 , respectively. The upper electrode 13 is a segment electrode that contains two or more openings 17 , while the lower electrode 15 is a common electrode. The liquid crystal layer 30 has a retardation, Δnd, of larger than 450 nm. The relations among the direction of the absorption axis in the polarizing plate, the direction of the slow axis in the viewing angle compensation plate, and the orientation direction or the liquid crystal director arrangement in the liquid crystal layer 30 are the same as in the second conventional liquid crystal display element. The characteristics of the various films and liquid crystal layers are also the same. Thus, the existence/absence of openings in the segment electrode is the primary difference between the liquid crystal display element according to the embodiments and the second conventional liquid crystal display element.
[0052] Black masks that cover the spaces between segment electrodes 13 , the spaces between common electrodes 15 , and the openings 17 may be formed to prevent light leakage that can occur at the dark state on passive-matrix driving. After forming the black masks 6 on the transparent substrate 4 , a resin layer 7 may be formed to serve for forming a smooth-surfaced electrode thereon as illustrated in FIG. 1 . The electrodes may be formed on the transparent substrate, followed by the formation of black masks directly in the regions that are not sandwiched between opposed electrodes. The black masks may be formed on both upper and lower substrates in the regions that are not sandwiched between opposed electrodes. They may be formed only on either substrate in the regions that are not sandwiched between opposed electrodes.
[0053] Preparation of the vertically aligned liquid crystal display element according to the embodiments is described below with reference to FIG. 1 .
[0054] A glass substrate having an ITO (indium tin oxide) transparent electrode with a substrate size of 350 mm×360 mm, a thickness of 0.7 mm, and a sheet resistance of 80Ω/□ is coated with a positive photoresist (supplied by Rohm and Haas Company) using a roll coater to form a photoresist film. A Cr (chrome) patterned photomask consisting of a quartz blank and a desired Cr (chrome) pattern formed on it is placed on a photoresist film they are closed adherence each other, followed by exposure process of the photoresist film using ultraviolet ray. Pre-bake is carried out at 120° C. for 10 minutes, and wet development processing is performed in an aqueous KOH solution to remove the photoresist in the unexposed portion. The ITO transparent electrode is etched with a ferric chloride solution at 40° C. to remove the ITO film from around the openings in the photoresist film. Finally, the remaining photoresist is removed with an aqueous NaOH solution. In this way, by using an appropriate photomask with a desired pattern, a segment electrode 13 with openings 17 and a common electrode 15 are formed on the upper and lower substrates 4 and 5 , respectively. Details of the segment electrode 13 , the common electrode 15 and the openings 17 will be described later.
[0055] Then, a material solution for the vertical alignment film (supplied by Chisso Petrochemical Corporation) is coated over the segment electrode 13 and the common electrode 15 by the flexographic printing method and pre-baked in a clean oven at 180° C. for 30 minutes to form vertical alignment films 12 and 14 . Subsequently, each of the films 12 and 14 is rubbed.
[0056] Then, either of the upper substrate 4 or the lower substrate 5 on which the vertical alignment film 12 or 14 has been formed is coated with a sealant (supplied by Mitsui Chemicals, Inc.) containing a silica spacer with a particle diameter of 2 to 6 μm by the screen printing method to form an intended pattern. A plastic spacer with a particle diameter of 2 to 6 μm is scattered over the other substrate by the dry spraying method. The upper and lower substrates 4 and 5 are bonded with each other after being set up so that the vertical alignment films 12 and 14 are faced with each other with the rubbing directions in the vertical alignment films 12 and 14 being anti-parallel to each other. Baking is carried out under a required pressure, followed by cutting to an intended size to complete an empty cell. The cell thickness is about 4 μm in the embodiments.
[0057] Then, a liquid crystal material (supplied by Merk & Co., Inc.) with a dielectric constant anisotropy of Δ∈<0 and a birefringence of Δn=0.21 is injected in the empty cell by vacuum injection, followed by sealing. Subsequently, baking is carried out at 120° for 60 minutes, followed by washing with a neutral detergent to complete a liquid crystal cell 9 .
[0058] Finally, viewing angle compensation plates 3 a and 3 b are formed outside the liquid crystal cell 9 , and upper and lower polarizing plates 10 and 20 (SHC13U supplied by Polatechno Co., Ltd.) are provided outside the former plates in such a way that their absorption axes are nearly in a crossed Nicols arrangement. In the present embodiments, negative biaxial films with an in-plane retardation of 12 nm and a thickness-direction retardation of 350 nm are used as the viewing angle compensation plates 3 a and 3 b.
[0059] Thus, a vertically aligned liquid crystal display element having viewing angle compensation plates and having openings in the electrodes is completed. In the present embodiments, black masks 6 for light leakage prevention and a resin layer 7 for formation of smooth-surfaced transparent electrodes 13 and also for electrical insulation are formed on the upper substrate 4 in the regions that are not sandwiched between opposed electrodes. The black masks comprise such materials as metal, resin containing a dispersed pigment, and resin containing dispersed carbon particles. It is noted that such black masks and resin layer may not always necessary.
[0060] The shapes of the electrodes used in embodiment samples Sa 1 to Sa 4 are described below with reference to FIGS. 2 to 5 .
[0061] FIGS. 2A to 2C are plan views illustrating the segment electrode arrangement pattern, common electrode arrangement pattern, and some pixels resulting from their overlap in the liquid crystal display element described in an embodiment sample Sa 1 . The segment electrodes 13 a extended in the alignment direction and the common electrodes 15 a extended perpendicular to the segment electrodes have a strip-like shape with a width S or C of 0.42 mm and a gap Ss or Cs of 0.01 mm. The pixels 18 a are defined in the form of rectangles located in the regions where the liquid crystal layer is sandwiched between the segment electrode 13 a and the common electrode 15 a . The openings 17 a are formed in the segment electrodes 13 a so that they are included in the pixels 18 a . Each opening 17 a is in the form of a rectangle with a long-directional length Al of 0.32 mm, a long-directional gap As of 0.1 mm between adjacent ones in the electrode, and a short-directional length Aw of 0.007 mm. Edges of the openings are parallel to edges of the segment electrodes 13 a in their extensive direction. It is noted that in the figures, the openings are illustrated in a larger size than actual for easy understanding.
[0062] FIGS. 3A to 3C are plan views illustrating the segment electrode arrangement pattern, common electrode arrangement pattern, and some pixels resulting from their overlap in the liquid crystal display element described in an embodiment sample Sa 2 . The segment electrodes 13 b extended in the alignment direction have a serrated shape with a serration angle of 90°, a serration interval Sw of 0.42 mm, a width S of 0.43 mm, and a gap between adjacent ones Ss of 0.01 mm. The common electrodes 15 b extended perpendicular to the segment electrodes 13 b have a strip-like shape with a width C of 0.42 mm and a gap Cs of 0.01 mm. The pixels 18 b are defined in an inverted dogleg shape in the regions where the liquid crystal layer is sandwiched between the segment electrodes 13 b and the common electrodes 15 b . The openings 17 b are formed in the segment electrodes 13 b so that they are included in the pixels 18 b . Each opening 17 b is in the form of an inverted dogleg shape with a long-directional length Al of 0.32 mm, a long-directional gap As of 0.1 mm between adjacent ones in the electrodes and a short-directional length Aw of 0.007 mm. Edges of the openings are parallel to edges of the segment electrodes 13 b in their extensive direction. It is noted that in the figures, the openings are illustrated in a larger size than actual for easy understanding. The pixels and openings may have a normal dogleg shape. For the present invention, both the normal dogleg shape and the inverted dogleg shape are simply referred to as dogleg shape.
[0063] FIGS. 4A to 4C are plan views illustrating the segment electrode arrangement pattern, common electrode arrangement pattern, and some pixels resulting from their overlap in the liquid crystal display element described in an embodiment sample Sa 3 . The segment electrodes 13 c and extended in the alignment direction have a strip-like shape with a width S of 0.42 mm and a gap Ss of 0.01 mm. The common electrodes 15 c extended perpendicular to the segment electrodes 13 c have a serrated shape with a serration angle of 90°, a serration interval Cw of 0.42 mm, a width C of 0.43 mm, and a gap between adjacent ones Cs of 0.01 mm. The pixels 18 c are defined in an inverted “V” shape in the regions where the liquid crystal layer is sandwiched between the segment electrodes 13 c and the common electrodes 15 c . The openings 17 c are formed in the segment electrodes 13 c so that they are included in the pixels 18 c . Each opening 17 c is in the form of a rectangle with a long-directional length Al of 0.32 mm, a long-directional gap As of 0.1 mm between adjacent ones in the electrode, and a short-directional length Aw of 0.007 mm. Edges of the openings 18 c are parallel to edges of the segment electrodes 13 c in their extensive direction. It is noted that in the figures, the openings are illustrated in a larger size than actual for easy understanding. The pixels may have a normal “V” shape. For the present invention, both the normal “V” shape and the inverted “V” shape are simply referred to as “V” shape.
[0064] FIGS. 5A to 5C are plan views illustrating the segment electrode arrangement pattern, common electrode arrangement pattern, and some pixels resulting from their overlap in the liquid crystal display element described in an embodiment sample Sa 4 . The segment electrodes 13 d extended in the alignment direction and the common electrodes 15 d have a serrated shape with a serration angle of 90°, a serration interval Sw or Cw of 0.42 mm, a width S or C of 0.43 mm, and a gap between adjacent ones Ss or Cs of 0.01 mm. The pixels 18 d are defined in the form of rectangles located in the regions where the liquid crystal layer is sandwiched between the segment electrode 13 d and the common electrode 15 d . Each opening 17 d is in the form of an inverted “Z” shape. It is noted that in the figures, the openings are illustrated in a larger size than actual for easy understanding. The openings may have a normal “Z” shape. For the present invention, both the normal “Z” shape and the inverted “Z” shape are simply referred to as “Z” shape.
[0065] FIG. 6A is a graph illustrating the dependence of transmittance characteristics on the observation angle (−60° to +60° for the samples Sa 1 to Sa 4 and a reference sample Ref. FIG. 6B is a table that shows x,y chromaticity observations according to the XYZ colorimetric system at an observation angle of 0°, 40° or 60° for the samples Sa 1 to Sa 4 and the reference sample Ref. Here, the reference sample Ref has the same structure as the above-mentioned second conventional liquid crystal display element. The samples Sa 1 to Sa 4 and the reference sample Ref were multiplex-driven under the conditions of 250 Hz frame frequency, 1/64 duty, 1/12 bias, and a voltage that gives the maximum contrast.
[0066] It is observed in FIG. 6A that the transmittance in the case of observation from the normal direction (observation angle 0°) is lower for the samples Sa 1 to Sa 4 than for the reference sample Ref. This is considered to be because the samples Sa 1 to Sa 4 have openings in the segment electrodes to reduce the effective aperture ratio. For all of the samples Sa 1 to Sa 4 , however, the transmittance improves at large observation angles, making the shape of the transmittance characteristics curves considerably flat as a whole. In particular, it is seen that the changes in hue in the observation angle range from 40° to 60° in the samples Sa 1 to Sa 4 are significantly smaller than those in the reference sample Ref.
[0067] These results indicate that in a vertically aligned liquid crystal display element provided with a viewing angle compensation plate on both sides of the liquid crystal cell, the viewing angle characteristics are improved when openings are formed in either of the opposed electrodes in such a manner that the edges of the openings are parallel to the edges of the electrode in the extensive direction. Specifically, in said liquid crystal display element, the transmittance characteristics flatten and the changes in hue decrease.
[0068] The present inventors continued study for evaluation of the influence of the number of openings formed in each pixel in a vertically aligned liquid crystal display element having viewing angle compensation plates and having openings in the electrodes.
[0069] FIGS. 7A to 7C are plan views illustrating the segment electrode arrangement patterns used in samples Sa 5 to Sa 7 . In the samples Sa 5 to Sa 7 , each liquid crystal display element has a structure similar to that in the sample Sa 1 , in which one to three openings are aligned in the direction perpendicular to the extensive direction of the segment electrodes (i.e. the left and right direction). In the sample Sa 5 , the openings 17 are formed in the segment electrodes 13 so that they are located in the central region of each pixel as seen in FIG. 7A . Namely, the sample Sa 5 is same as the sample Sa 1 . The sample Sa 6 provides a sample in which two openings are contained in each pixel and located at regular intervals in the extensive direction of the segment electrodes as illustrated in FIG. 7B . The sample Sa 7 provides a sample in which three openings are contained in each pixel and located at regular intervals in the extensive direction of the segment electrodes as illustrated in FIG. 7C .
[0070] FIG. 8A is a graph illustrating the dependence of transmittance characteristics on the observation angle (−60° to +60° for the samples Sa 5 to Sa 7 and a reference sample Ref. FIG. 8B is a table that shows x,y chromaticity observations according to the XYZ colorimetric system at an observation angle of 0°, 40° or 60° for the samples Sa 5 to Sa 7 and the reference sample Ref. These graphs suggest that in any of the samples Sa 5 to Sa 7 , the transmittance improves and the changes in hue decrease at larger observation angles than in the reference sample Ref. With respect to the influence of the number of openings contained in each pixel, it is found that the light transmittance improves and the color shift decrease at larger observation angles in the left and right direction as the number of openings increases. With respect to the changes in hue, it is noted that slight yellowing was found as the number of openings increased.
[0071] Discussed below is the mechanism of the improvement in viewing angle characteristics brought about by the formation of openings in the electrodes in a vertically aligned liquid crystal display element having a viewing angle compensation plate on both sides of the liquid crystal cell.
[0072] FIGS. 9A and 9B are a schematic figure illustrating the electric field around the edge of an opening under an applied voltage and a front perspective view schematically illustrating oriented molecules at the thickness-direction center of a liquid crystal layer. In the absence of applied voltage, liquid crystal molecules with a negative dielectric constant anisotropy are oriented nearly vertically to the substrate. When a voltage is applied between the electrodes, liquid crystal molecules are reoriented in the alignment direction to produce a light state in regions where an electrode exists on both the upper and lower substrates. On the other hand, liquid crystal molecules are not reoriented, failing to produce a light state, in the central region of the opening where an electrode exists only on the upper substrates. Thus, it is considered that the effective aperture ratio decreases and the transmittance also decreases in the case of observation from the normal direction as a result of the formation of openings in the electrodes. Around the edge of an opening, on the other hand, the electric flux lines coming from the portions of the electrodes opposite to each other around the opening are directed towards the edge of the opening, leading to oblique electric fields as depicted in FIG. 9A . The liquid crystal molecules located around the edge of the opening are reoriented locally along these oblique electric fields. On the substrate plane, the orientation direction of the liquid crystal molecules gradually comes closer to the alignment direction at positions away from the edge of the opening, possibly resulting in multi-domain orientation in the liquid crystal layer under an applied voltage as seen in FIG. 9B . Noted that in FIGS. 9A and 9B , the oblique electric fields and the liquid crystal molecule orientation direction around the edge of the opening are depicted only for their components perpendicular to the alignment direction, but actually a similar phenomenon must be taking place at other edge regions of openings. Thus, it is considered that the formation of openings in the electrodes leads to oblique electric fields around the edge of each opening to cause multi-domain orientation in the liquid crystal layer, resulting in averaged refractive index changes over a range of observation directions and improved viewing angle characteristics. In the case where the openings have a complicated shape containing a bent portion as in the samples Sa 3 and Sa 4 (such as dogleg shape and “Z” shape) or where two or more openings are contained in each pixel as in the sample Sa 7 , in particular, it considered that the multi-domain orientation regions increase in size during voltage application to bring about a significant improvement in viewing angle characteristics as observed above.
[0073] FIGS. 10A and 10B are a schematic figure illustrating the electric field around the edge of a pixel under an applied voltage and a front perspective view schematically illustrating oriented molecules at the thickness-direction center of a liquid crystal layer. It is considered that electric flux lines generated by the opposed electrodes in the spaces between segment electrodes or between common electrodes extend towards the edges of the respective electrodes to produce oblique electric fields around the edges of each pixel as illustrated in FIG. 10A through the same mechanism as for the electric fields around the edges of each opening. It is likely that the liquid crystal molecules located near the edges of a pixel are re-oriented locally along these oblique electric fields to produce a multi-domain orientation region as illustrated in FIG. 10B . This multi-domain orientation region formed around the edges of a pixel is also expected to contribute to the improvement in viewing angle characteristics. In the case of a pixel of a shape containing edges that intersect with perpendiculars to the alignment direction as in the samples Sa 2 and Sa 3 (such as “V” shape and dogleg shape), in particular, a larger multi-domain orientation region is expected to be produced to contribute to the improvement in viewing angle characteristics.
[0074] As discussed above, it appears to be preferable that in the case where importance is given to improvement in the viewing angle characteristics at large observation angles, the size of the openings in the long-direction is increased in the extensive direction while the size of the openings in the width direction and their intervals in the width direction are reduced to increase their density, in order to increase the size of the multi-domain orientation regions in the liquid crystal layer. Here, the long-directional gaps between the openings may be eliminated to form one continuous opening extending in the electrode extensive direction. The openings may have, for instance, a “X”, “U”, “S”, or “O” shape containing a bent portion and may be extended in the extensive direction of the electrodes that contain them.
[0075] Openings may be formed in the common electrodes instead of the segment electrodes, or may be formed in both the common electrodes and segment electrodes. The relations among the direction of the extending opening and the extending electrode, the alignment direction, the direction of the absorption axis in the polarizing plate and so on may not be the same as the embodiments. The embodiments use a negative biaxial film on both sides of the liquid crystal cell, but this invention is not limited thereto. A negative uniaxial film may be provided on one side of the liquid crystal cell and a negative biaxial film may be provided on the other side of the liquid crystal cell. The viewing angle compensation plate provided on one side of the liquid crystal cell and the viewing angle compensation plate provided on the other side may have different optical characteristics. It is known that in general, the thickness-direction retardation in a viewing angle compensation plate is preferably about 0.5 to 1 times the retardation in the liquid crystal layer. Then two or more viewing angle compensation plates may be used to adjust the thickness-direction retardation in cases where the retardation of the liquid crystal layer would be too large.
[0076] All examples and conditional language recited herein are intended for pedagogical purposes to aid the leader in understanding the invention and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although the embodiments of the present invention have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.
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A simple matrix type dot-matrix liquid crystal display element includes a first and a second transparent substrate disposed opposite to each other, first and second transparent electrodes disposed on the opposed face of the first and the second transparent substrate, respectively, a first and a second vertical alignment film disposed on the opposed side of the first and the second transparent substrate to cover the first and the second electrodes, respectively, a liquid crystal layer disposed between the opposed side of the first and the second transparent substrate and having Δ∈<0 and Δnd>450 nm, and a first and a second viewing angle compensation plate disposed on the unopposed side of the first and the second transparent substrate, respectively, wherein in the first transparent electrode, openings extending in a predefined direction are aligned.
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TECHNICAL FIELD OF THE INVENTION
The present invention is in the field of silicon photovoltaic cells and more particularly relatively thin, mass-produced, flexible, multi-layer silicon alloy solar cells having an enhanced efficiency and method and apparatus for producing same.
BACKGROUND OF THE INVENTION
Silicon is a quite brittle material which is quite difficult to slice thinner than approximately 250 microns. Since the minority electrical carrier diffusion length through single-crystal silicon material averages about 200 microns at an intensity of one sun through air mass one (AM1), only a relatively small proportion of the electrical carriers generated by incident solar radiation can be collected in a silicon cell having such a thickness as 250 microns. Therefore, the overall conversion efficiency of such thick silicon solar cells is low.
Consequently, attempts have been made in the prior art to produce thinner, wafer-type silicon solar cells. Prior art attempts to produce silicon photovoltaic cells much thinner than 250 microns have involved expensive, time-consuming lapping procedures for producing a micro-smooth surface, followed by expensive, time-consuming etching procedures considerably raising the cost of the completed cell and considerably limiting the overall production rate capability. Even when these procedures are used to produce thin silicon solar cells, their conversion efficiencies in commercially produced wafer-type units seldom exceed 15% at one sun at AM1.
Attempts have been made in the prior art to pull ribbons of silicon directly from a melt. To date such ribbon-pulling-produced solar cells have been plagued by defects and have occasionally, but not consistently, exhibited conversion efficiencies in laboratory-produced (not commercially produced) units up to approximately 16% at one sun at AM1, with a ribbon thickness of approximately 100 microns. The rate at which each such ribbon has been pulled from a melt is very slow, being of the order of one to twenty square centimeters of ribbon per minute at a thickness of less than 150 microns.
As used herein, "one sun" means the intensity of solar radiation as actually received from the sun without augmentation.
As used herein, "air mass one" or "AM1" means the average maximum solar radiation received at the earth's surface at sea level resulting from solar radiation passing vertically through one thickness of atmosphere.
SUMMARY OF THE DISCLOSURE
The present invention overcomes or substantially eliminates the shortcomings of the prior art as applied to thin silicon solar cells. This invention enables thin-film silicon solar cells to be produced relatively rapidly and at significantly lower costs as compared with the prior art.
A multi-layer, thin-film, flexible silicon alloy solar cell is described in which the multiple layers extend perpendicularly to the incident light. The flexible cell is mass-produced by rolling and laminating two thin ribbons of silicon alloy having thicknesses of the order of 10 to 50 microns. with each ribbon passing through multiple rolling stages employing a ceramic metallic glass semi-conductor alloy of silicon having approximately a zero coefficient of thermal expansion/contraction. The rolling pressure in at least one of the rolling stages is applied while this silicon alloy is in a semi-liquidus condition for producing plastic deformation enhancement of the material.
This ceramic metallic glass alloy of silicon melts at a relatively low temperature in the range from approximately 800° C. to 1,150° C. (1,472° F. to 2,102° F.). In contrast, the liquidus temperature of silicon is 1,410° C. (2,570° F.). By virtue of this relatively low melting temperature of the silicon alloy, the rolling and doping of each moving ribbon can be carried out at a correspondingly relatively low temperature, thereby considerably diminishing the tendency of this molten alloy to pick up contaminants from surfaces of the extruding and rolling processing apparatus. This diminished dissolving tendency is an advantage compared with the normal tendency of molten silicon to dissolve and absorb materials from surfaces with which it comes into contact.
During the rolling of the two silicon alloy ribbons, gaseous dopants are applied to them. The rolling pressure on each ribbon facilitates orientation of the crystal lattice structure in the desired direction in the ribbons with relatively few undesired grain boundaries occurring in each ribbon.
The two silicon alloy ribbons are laminated together with a very thin lattice matching layer of less than 60 Angstroms thickness between, and the resultant laminate serves as a substrate on which other layers are deposited. This laminate forms the two main active layers of the photovoltaic cell. The very thin lattice matching layer of less than 60 Angstroms thickness serves to match the crystal lattice structure of these two active layers. This lattice matching layer may be an insulating layer less than 20 Angstroms thick or a semi-conducting oxide layer.
On the front of this laminate, i.e. facing the incident radiation, are six additional layers. The lowermost of these six additional layers, that is, the closest to the laminate (called the "sixth" of these six layers) is a semi-insulating layer less than 10 Angstroms thick (preferably 6 to 9 Angstroms thick) containing cobalt and tin applied by metal organic chemical vapor deposition. This thin semi-insulating layer acts as a passivating layer for lowering surface recombination and for helping to minimize the crystal lattice mismatch. Moreover, this sixth layer has a bright green-to-blue color and acts as a spectral filter for excluding incident radiation having a wavelength longer than the middle of the near infra-red range, i.e. having a wavelength longer than approximately 12,000 Angstroms (visible light is in the range from about 4,000 Angstroms to about 7,200 Angstroms) for keeping the cell operating relatively cool by filtering out the longer near infra-red and the far infra-red wavelengths which do not contribute to electrical output of the cell.
The next lowermost (fifth) of these six layers is a semi-conductive "window" layer containing wet-chemical-vapor-deposited tin oxide having a thickness in the range from 300 to 850 Angstroms (preferably 650 to 750 Angstroms). This fifth layer serves as the primary protective layer for protecting the cell from degradation due to attack from oxidizing agents or atmospheric pollution, such as sulphur-containing compounds. This semi-conductive "window" layer is transparent for incoming radiation, but it acts as an optical mirror for internal light rays which have been reflected from the back for preventing escape of these internal light rays. Moreover, this semiconductive window layer advantageously operates as a collection layer in cooperation with the layers beneath.
The next lowermost (fourth) of these six layers is a chemical-vapor-deposited, thin insulating layer less than 15 Angstroms thick for electrically insulating a front electrical collection grid from the semi-conductive window layer described immediately above. This thin insulating layer acts as a tunneling layer for allowing the electrical current carriers to reach the collection grid.
The front three-layer assembly of the six comprises a triple-layer, anti-reflection coating (ARC) covering the front face of the cell. In this three-layer ARC assembly the middle (second) layer serves to bond the other two ARC layers together and advantageously acts as a secondary, protective glass-like layer for protecting the photovoltaic cell from degradation due to attack from oxidizing agents or pollutants in the atmosphere.
In this three-layer ARC assembly there is a reflective rear (third) layer which cooperates with the transparent mirror-like "window" layer described above for advantageously acting as an internal mirror. This internal mirror advantageously causes radiation in the visible range of the electromagnetic spectrum ("light rays") to be reflected back and forth within the cell between the rear and front of the cell for traversing the light rays multiple times back and forth through the cell for improving the likelihood of photovoltaic interaction between the photons of light and the active photovoltaic regions of this cell.
In this three-layer ARC assembly, there is a top (first) layer mainly comprised of silicon dioxide having a thickness in the range from 200 to 650 Angstroms. This top layer is on the front face of the solar cell.
The six layers described above which are on the front of the ribbon laminate effectively adapt the overall cell to be receptive to incident solar radiation in the range from about 4,000 to about 12,000 Angstroms and effectively to exclude radiation outside of this range. This range comprises approximately 68 percent of the solar radiant energy reaching the earth's surface vertically through the thickness of one atmosphere.
The rear of the laminate, which forms the rear of the cell, preferably has an undulating configuration for redirecting the reflected light rays along randomized paths for further improving the likelihood of inter-action of the photons with these active regions.
Method and apparatus are described for producing the two ceramic metallic glass semi-conductor silicon alloy ribbons and for laminating them together.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention, together with further objects, features, advantages and aspects thereof will become more clearly understood from a consideration of the following description in conjunction with the accompanying drawings in which like elements will bear the same reference numerals. The drawings are not necessarily drawn to scale, emphasis instead being placed upon clearly illustrating this invention in the best mode now contemplated for putting this invention into practice.
FIG. 1 is an enlarged cross section of a portion of a solar cell embodying the present invention.
FIG. 2 is a plan view of the front face of the solar cell drawn approximately one and a half times actual size.
FIG. 3 is an enlargement of a portion of FIG. 2.
FIG. 4 is a partial perspective view of a portion of FIG. 3 shown further enlarged.
FIG. 5 is an enlarged partial sectional view of a main bus taken along the line 5--5 in FIG. 2.
FIG. 6 is an enlarged partial sectional view of one of the front contact members taken along the line 6 in FIG. 2. FIG. 6 also corresponds to an enlargement of the front contact seen in FIG. 1 and an enlargement of this same front contact seen at the left in FIG. 5.
FIG. 7 is an enlarged partial sectional view of an intermediate bus taken along the line 7--7 in FIG. 2.
FIG. 8 is an enlarged partial sectional view of a side rail bus, being a section taken along the line 8--8 in FIG. 2.
FIG. 9 is a diagrammatic illustration of the ribbon laminate production method and apparatus.
FIG. 10 is a diagrammatic illustration of further production method and apparatus continuing from the right of FIG. 9.
FIG. 11 is an enlarged view of a portion of FIG. 9.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
FIG. 1 is a partial cross-sectional elevational view of a multi-layer, thin-film, flexible photovoltaic cell 20 embodying the present invention. The various layers of this cell are not drawn to scale whether vertically or horizontally, but rather are drawn to illustrate clearly the principles of this invention. The front (top) is indicated at 21 and is intended to face the incident solar radiation. This front 21 is generally planar except for the regions in which are located the front contact members 27 (FIG. 4), the intermediate bus bars 28 (best seen in FIGS. 3 and 4), the main bus bars 29 (FIGS. 3 and 4), and the side rail buses 26 (FIGS. 2 and 8), which will be described in detail further below.
The rear (bottom) is indicated at 22, and it preferably has a non-planar configuration, being defined by a sequence of pairs of sloping planes 23 and 24 with rear contact members 25 extending along the lowermost regions between these sloping planes 23 and 24, as will be described in detail further below.
During fabrication of this flexible, thin-film photovoltaic cell 20, the first step is formation of a substrate ribbon laminate 100 by the method and apparatus shown in FIGS. 9, 10 and 11. There is a first extruder 101 for extruding a molten viscous ceramic metallic glass silicon alloy forming a pre-ribbon 51A (FIGS. 9 and 11) passing through a sequence of rolling stations 102, 104, 106, respectively, including pairs of opposed rollers 111 and 112, 113 and 114, 115 and 116 located in a sequence of heated chambers 117, 118 and 119, respectively. These chambers are separated from each other by partitions 120. Each such partition 120 includes a baffled port 121 for enabling the moving ribbon to travel through this port while preventing any significant flow of the gaseous content of a chamber into a neighboring chamber. It is to be understood that each port 121 may include a plurality of baffles extending close to the travelling ribbon for preventing the gaseous content of one chamber from entering the next chamber.
There are pairs of gaseous diffusion tubes 131 and 132, 133 and 134, 135 and 136 extending into the respective chambers 117, 118 and 119. These gaseous diffusion tubes disperse gaseous dopants onto the opposite surfaces of the hot moving ribbon of silicon alloy. By virtue of the fact that the rolling pressure of the opposed pairs of rollers 111 and 112, 113 and 114, 115 and 116 is applied to the hot silicon alloy ribbon soon after the gaseous dopant has been dispersed onto the hot upper and lower surfaces thereof, the rate of diffusion of the dopant into the ribbon is enhanced, as compared with the prior art procedures of diffusing dopant into already crystallized silicon material. This hot silicon alloy ribbon 51A is reduced in thickness as it passes between the opposed pairs of rollers in the rolling stations 102, 104 and 106. The ribbon after reduction in thickness is shown at 51 in FIG. 9 exiting from the roller station 106 and entering an ion implant station 107.
Before describing the ribbon laminate production method and apparatus further, attention is invited to FIG. 1. It is seen that the substrate ribbon 51 has a planar front surface 47 and preferably an undulating rear surface 22. This undulating rear surface 22 includes a repetitive sequence of pairs of sloping planes 23 and 24 each of which slopes at an acute angle in the range from approximately 10° to 15° to the horizontal. There are planar areas 64 located between and contiguous with the lower limits 63 (FIG. 1) of the downwardly sloping planes 24 and the lower limits 65 of the next successive upwardly sloping planes 23. This ribbon 51 has a nominal thickness of approximately 35 microns plus or minus 5%, i.e. ±1.75 microns. In other words, this ribbon 51 has a thickness of approximately fourteen ten thousandths of an inch (0.0014) inch.
This substrate ribbon 51 varies in thickness due to the presence of the sloping planes 23 and 24. The minimum thickness occurs in the vicinity of the peaks 68 of the pairs of sloping planes 23 and 24 and is in the range from approximately 18 microns to 26 microns, depending upon the tolerances and depending upon whether the slope angle is nearer 15° to 10°. The peak-to-peak distance between the successive peaks 68 is approximately 150 microns (six thousandths of an inch).
This ribbon 51 is formed as shown in FIG. 11 by extruding viscous molten silicon alloy material 70 from the extruder 101. This alloy 70 is a ceramic metallic glass alloy of silicon which melts at a relatively low temperature in the range of approximately 800° C. to 1,150° C. The alloy 70 is in a semi-liquidus condition as it enters the nip region 122 (FIG. 11) between the first pair of rollers 111, 112. This alloy composition 70 for forming the rear ceramic metallic glass silicon alloy semiconductor ribbon 51 is characterized by the indicated weight percent of the following elements:
______________________________________ Range in Weight PercentIngredient of Total Composition______________________________________Silicon 51-88%Lithium 3-30%Aluminum 0.5-29%Fluorine 0.5-8%Hydrogen 1-12%Vanadium 0-5%Trace Elements, Less than 0.19Including Oxygen______________________________________
An example of a presently preferred composition of this ceramic metallic glass silicon alloy semiconductor material 70 is:
______________________________________ Weight Percent ofIngredient Total Composition______________________________________Silicon 66.5 to 68.1%Lithium 22.6%Aluminum 2.3%Fluorine 1.5%Hydrogen 5.5%Vanadium Less than 1.5%Trace Elements Less than 0.1%______________________________________
Inviting attention back to FIG. 11, the nip region 122 is between cooled circular cylindrical rollers 111 and 112. The surfaces of these opposed counter-rotating rollers 111 and 112 are micro-roughened by selectively etching their surfaces for providing a grip (traction) on the viscous alloy 70. These rollers 111, 112 are adjustably spaced apart for producing the first ribbon stage 51A. It is to be noted that these rollers have a diameter of at least 15 centimeters and are formed of a machineable ceramic glass alloy which is cast and then machined and ground to tolerance, followed by the etching step for producing traction as discussed.
The ceramic glass alloy composition of the rollers 111, 112 is made as follows: Silica is dry mixed as a powder with alumina powder and with lithium dioxide powder. This lithium dioxide comes in the form of the naturally occurring mineral Petalite or Spodumene, preferably using the latter mineral, because it is more readily obtained in the United States. The dry mixture is heated in a crucible made of alumina or SIALON or SION, or fused quartz or silicon nitride. When molten, the composition is purified to remove substantially all oxygen and other trace elements which would contaminate the ribbon being rolled. The purified roller composition is characterized by the indicated weight percent of the following elements:
______________________________________ Weight Percent ofIngredient Total Composition______________________________________Silicon 50 to 70Aluminum 10 to 25Lithium 5 to 35Oxygen & Trace Elements Less than 1______________________________________
As explained above, this machineable ceramic glass alloy composition is cast to shape, machined and ground to tolerance and then selectively etched for providing surface traction of the rollers 111, 112 on the molten alloy 70.
The molten alloy 70 entering the nip 122 is formed by extrusion through a wide slot orifice 78 in the nozzle 80 of the extruder 101. The vertical dimension of the slot orifice 78 is considerably greater than the spacing between the pair of opposed rolls 111, 112. The extruder and its interchangeable nozzle 80 are formed of a machineable ceramic glass composition including the above ingredients. The machineable ceramic glass for the extruder and its nozzle is more refractory than that used to make the rollers. The width of the wide slot orifice 78 is at least 4 centimeters, and the slot has a height of at least 100 microns for forming an extrudate ribbon mass 70 of approximately these dimensions.
As described above, the rollers 111, 112 are adjustably spaced apart, thereby producing the first stage ribbon 51A with a thickness reduction of at least 30% from the entering mass.
Between the nozzle 80 and this first pair of rollers are shown gaseous diffusion tubes 131, 132, respectively, aimed at the opposite surfaces of the material 70 for dispersing gaseous dopants onto these surfaces. The gaseous dopants are being released from these tubes 131, 132 at a pressure exceeding one atmosphere. These gaseous dopants are attracted to the hot upper and lower surfaces of the semi-liquidus alloy material 70. The advantage of the rolling action and pressure in the various rolling stations 102, 104, 106 enhancing the diffusion of the dopants into the ribbon 51A is discussed above. After the first stage ribbon 51A has passed between the cooled rollers 111 and 112, it is in a semi-solidus condition. The relatively minute mass of this silicon alloy material 70 between these rollers enables the alloy to be very rapidly cooled from its semi-liquidus to its semi-solidus condition, thereby advantageously causing plastic deformation with quick cooling for orienting the multi-crystalline structure in the direction of rolling, i.e. parallel with the front and rear surfaces of the ribbon 51 being formed.
It is my theory that this orientation will slightly raise the upper limit of the band gap of the silicon alloy ribbon for making the substrate 51 of the solar cell responsive photovoltaically to visible light over a broader frequency range, i.e. extending up to a slightly higher frequency than would occur in this same alloy material without such rolling. However, this theory, whether borne out in practice or not, is not critical to the present invention. Its effect, if present, is a further advantage of this production method and apparatus.
The gaseous dopant which may be supplied through the tube 131 is a phosphorous-containing gas, for example, phosphine (PH 3 ). This same gaseous dopant is supplied through the other tubes 133 and 135 which face the same "front" surface of the ribbon 51 being formed. Depending upon desired dopant density and gaseous distribution, any one, or more, or all of these tubes 131, 133 and 135 may be utilized.
It is noted, as indicated above, that the term "front" or "top" is intended to indicate a region in the completed cell 20 facing toward the incident light radiation, while the term "rear" or "bottom" is intended to mean a region in the cell facing away from the incident light.
The gaseous dopant being supplied through the tubes 132, 134 and 136 to the "rear" surface of the ribbon 51 being formed is a boron-containing gas, for example, boron trifluoride (BF 3 ). Depending upon desired dopant density and gaseous distribution, any one, or more, or all of these tubes 132, 134 and 136 may be utilized.
The second pair of adjustably spaced circular cylindrical rollers 113 and 114 in station 104 are constructed the same and have micro-roughened surfaces the same as the first pair 111, 112 in station 102.
These rollers 113 and 114 are adjusted to produce a reduction in thickness in the travelling ribbon of at least 30%.
The third pair of rollers 115 and 116 are adjustably spaced and are arranged to produce the exiting ribbon 51 having the thickness dimensions described above. This exiting ribbon has a width of at least 11 centimeters. The rollers 115 and 116 are constructed of the same material as the first and second pairs 111, 112 and 113, 114. The roller 115 is at least 20 cm in diameter and has a ground micro-smooth circular cylindrical surface. The circular cylindrical surface of the roller 116 which has a diameter of at least 20 cm is preferably machined to have a textured pattern which is the negative of the desired rear pattern 22 (FIG. 1) for producing this rear pattern 22. Alternatively, the surface of the roller 116 may be micro-smooth for producing a planar rear surface 22 on the ribbon 51.
The planar areas 64 and peaks 68 in the rear surface 22 extend parallel with each other and are oriented at an angle of approximately 60° with the length of the ribbon. They are arranged in a chevron pattern similar to the chevron pattern of the front contact members 27 (FIG. 3). The chevron pattern on the rear 22 is shifted laterally relative to the chevron pattern on the front 21 by an amount equal to the spacing between the intermediate bus bars 28 (FIG. 3), so that the planar areas 64 with their contact members 25 are oriented at an angle with respect to the front contact members 27.
Although three rolling stations 102, 104, 106 are shown, it is to be understood that more such stations may be included, depending upon the initial thickness of the extrudate 70 and the percentage reduction in each station. Also, it is to be understood that these stations 102, 104 and 106, and the ion implant station 107, may be arranged in a vertical line for causing the ribbon being rolled to travel vertically in the earth's gravitational field.
In the ion implant station 107, there is an evacuated chamber 123 containing ion guns 137, 138 which are preferably aimed at an acute angle, as shown, toward opposite surfaces of the advancing ribbon 51. The ion gun 137 is supplied with a gas containing phosphorous, for example, a mixture of phosphine and hydrogen. The other ion gun 138 is supplied with a gas containing boron, for example, a mixture of boron trifluoride and hydrogen.
The ribbon 51 passes a guide roller 124 and enters a laminating station 108. In this laminating station 108 there is a chamber 124 containing a plurality of electric heaters 140 for raising the temperature of the front surface 47 (FIG. 9) of the ribbon 51. A tube 142 feeds oxygen onto the heated front surface 47 for causing diffusion of the oxygen into this surface for forming the thin lattice matching layer 46 (FIG.1). This lattice matching layer 46 may be an insulating oxide layer less than 20 Angstroms thick or a semi-conducting oxide layer less than 60 Angstroms thick. Another tube 144 for aiding in forming this lattice matching layer 46 feeds oxygen into the region where the heated ribbon 51 is pressed by opposed adjustably spaced rollers 145, 146 against another heated ribbon 49 for forming the laminated ribbon 100. These laminating-pressure rollers 145 and 146 are constructed of the same material as the rollers 111 and 112. The laminating-pressure rollers 145 and 146 have micro-smooth surfaces and a diameter of at least 15 cm. If the roller 116 is textured, then preferably the roller 146 is similarly textured and is synchronized in motion with the existing pattern on the rear of the ribbon 51 for engaging this existing pattern without unduly distorting it. The roller 146 will then have the same diameter as the roller 116, and the roller 145 will have the same diameter as its opposed roller 146.
The ribbon 49 is formed as shown in FIG. 9 by extrusion of an extrudate 270 plus rolling, utilizing an extruder 201 followed by rolling stations 202, 204, 206 in which there are chambers 217, 218, 219, containing pairs of adjustably spaced rollers 211 and 212, 213 and 214, 215 and 216, respectively. The extruder 201 is identical to the extruder 101, and the rollers 211, 212, 213 and 214 are identical to the rollers 111, 112, 113 and 114. The rollers 215 and 216 are identical to the roller 115, and each has a micro-smooth surface for forming the planar front and rear surfaces 71 and 72 (FIG. 9) of the ribbon 49. The ribbon 49 has a thickness in the range from 15 to 20 microns and is at least 11 cm wide. The ceramic metallic glass semiconductor silicon alloy composition of the extrudate 270 for forming the ribbon 49 is characterized by the indicated weight percent of the following elements:
______________________________________ Range in Weight PercentIngredient of Total Composition______________________________________Silicon 51-88%Lithium 3-30%Aluminum 0.5-29%Fluorine 0.5-8%Hydrogen 0.5-12%Antimony 0.01-20%Cobalt 0.01-6%Trace Elements, Less than 0.1%Including Oxygen______________________________________
An example of a presently preferred composition of this ceramic metallic glass semiconductor silicon alloy material 270 is characterized by the indicated weight percent of the following elements:
______________________________________ Range in Weight PercentIngredient of Total Composition______________________________________Silicon 59.5-63.5%Lithium 25%Aluminum 4.9%Fluorine 1.3%Hydrogen 5.3%Antimony Less than 3%Cobalt Less than 1%Trace Elements, Less than 0.1%Including Oxygen______________________________________
Although three rolling stations 202, 204, 206 are shown, it is to be understood that more such stations may be included, depending upon the initial thickness of the extrudate 270 (FIG. 9) and the percentage reduction in each station. Also, it is to be understood that these stations 202, 204 and 206 and an ion implant station 207 may be arranged in a vertical line for causing the ribbon being rolled to travel vertically in the earth's gravitational field. The laminating station 108 may be arranged for travelling the two ribbons 49 and 51 essentially vertically as they are directed along converging paths and laminated.
There are tubes 231, 233, 235 and 232, 234, 236 for feeding gaseous dopants onto the front and rear surfaces, respectively, of the ribbon being rolled. The gaseous dopant supplied for the front surface of the ribbon 49 is phosphine, and that supplied for the rear surface is boron trifluoride. Depending upon the desired dopant density and gaseous distribution, any one, or more, or all of these tubes 231 through 236 may be utilized.
The ribbon 49 passes through an ion implant station 207 in which there is an evacuated chamber 223 containing ion guns 237, 238 which are preferably aimed at an acute angle, as shown, toward opposite surfaces 71, 72 of the advancing ribbon 49. The ion gun 237 is supplied with a gas containing phosphorous, for example a mixture of phosphine and hydrogen. The other ion gun 238 is supplied with a gas containing boron, for example, a mixture of boron trifluoride and hydrogen.
The ribbon 49 passes a guide roller 224 and enters the laminating station 108 in which the electric heaters 240 raise the temperature of the rear surface 72. A tube 242 feeds oxygen or nitrogen onto the heated rear surface 72 for causing diffusion of oxygen or nitrogen into this surface for forming the thin lattice matching layer 46 (FIG. 1) described above. The laminating-pressure rollers 145, 146 press the rear surface 72 of ribbon 49 against the front surface 47 of ribbon 51 for laminating them together to form the laminated ribbon 100.
It is to be understood that the thin lattice matching layer 46 (FIG. 1) formed in the laminated ribbon 100 includes thin portions of the rear and front surfaces 72 and 47, respectively, of the ribbons 49 and 51.
The laminated ribbon 100 passes between other pairs of opposed adjustably spaced rollers 147 and 148 in a heated bonding chamber 125 for causing the laminated ribbon to bond securely together. If the roller 116 is textured, then the rollers 148 and 147 preferably meet the same criteria as discussed above for rollers 146 and 145.
In the rolling chambers 117, 118 and 119, the ribbon 51 being formed is heated preferably to be at a level of approximately 20° C. to 60° C. below the semi-liquidus condition. Similarly, in the rolling chambers 217, 218, 219, the ribbon 49 being formed is heated preferably to be at said temperature level. In the laminating and bonding chambers 124 and 125 the ribbons 49, 51 and the laminated ribbon 100 are heated preferably to a level of approximately 20° C. to 60° C. below their semi-liquidus temperature. This temperature level is the preferred temperature for promoting crystal growth and orientation of crystals in the ribbons while rolling.
The opposed rollers in each pair are interconnected for causing them to rotate in opposite directions at the same speed. Each pair of rollers is driven independently of the other pairs. Means are provided, for example, optical sensors, for sensing any deflection or sag in the moving ribbons or in the laminate. The successive pairs of rollers are driven at appropriate speeds for minimizing any deflection or sag of the travelling ribbon or laminate away from the desired path.
The walls 90 of the chambers 117, 118, 119, 123, 124, 125, 217, 218 and 219 are formed of or lined with the same machineable ceramic glass alloy as the rollers therein. There are air-tight disconnectible flanged joints 92 for enabling disassembly of any chamber for obtaining access to the interior. Also, there are numerous vents 94 leading into the respective chambers which are normally closed by shut-off valves, as indicated in FIG. 11, but which may be opened for removing and changing the gaseous content of any chamber.
The gaseous diffusion and ion implant of dopant produce an n+ type layer 40 and a p+ type layer 44, while the main body 42 of the region 49 of the cell 20 is p type. The gaseous diffusion and ion implant of dopant produce an n+ type layer 48 and a p+ type layer 52, while the main body 50 of the region 51 of the cell 20 is p type.
The laminated ribbon passes a guide roller 150 and travels through baffled ports 121 in a series of partitions 120 and passes a guide roller 151, entering etching chamber 126. The etchant 152 is maintained at a temperature of 90° C. and comprises a one normal solution of hydrogen fluoride in water. The purpose of this etching step is to thoroughly clean the front and rear surfaces of the laminate ribbon 100. Advantageously, the temperature levels in the rolling, laminating and bonding stations as described promote crystal growth and orientation of the crystals. Then, the relatively cool etchant 152 at a temperature of 90° C. produces a rapid quench, thereby supercooling the laminate 100 and immediately stopping further crystal growth when the crystals are at their optimum crystalite size. The guide roller 151 is formed of material not dissolvable in the etchant 152. After the etching is completed, the travelling ribbon 100 passes another guide roller at the opposite end of the etching bath 152 from the guide roller 151 and exits from this bath.
The etched ribbon 100 is introduced into a rinse bath 154 (FIG. 10) in a rinse chamber 128. The rinse bath 154 is methanol. After the rinsing step is completed, the travelling laminate ribbon 100 passes a guide roller 156 and exits from the rinse bath 154. The rinsed travelling ribbon 100 passes through a series of baffled ports 121 in a sequence of partitions 120 and passes a guide roller 158 in readiness for further processing steps to be described.
The layer 38 (FIG. 1) is a semi-insulating layer less than 10 Angstroms thick and preferably in the range from 6 to 9 Angstroms thick. This thin, semi-insulating layer acts as a passivating layer for lowering surface recombination and for helping to minimize crystal lattice mismatch. This layer 38 is formed by metal organic chemical vapor deposition of cobalt nitride (CoN) together with tin oxide (SnO 2 ) onto the front surface of the laminate 100, at a ratio of approximately 58% cobalt nitride and approximately 42% tin oxide by weight at a temperature of approximately 460° C. This layer 38 containing cobalt and tin has a bright green-to-blue color and also advantageously acts as a spectral filter for excluding incident radiation having a wavelength longer than the middle of the near infra-red range. In other words, this layer 38 excludes incident radiation having a wavelength longer than approximately 12,000 Angstroms for keeping the cell operating relatively cool by filtering out the longer near infra-red, i.e. wavelengths longer than approximately 12,000 Angstroms, and the far infra-red wavelengths, all of which do not contribute to electrical output of the cell. The layer 38 also filters out ultraviolet radiation and thus prevents cell degradation by ultraviolet radiation damage.
The layer 36 is a semi-conductive "window" layer formed by wet chemical deposition spray of a tin-containing compound in solution, for example of tin fluoride (SnF 3 ) in alcohol in a 75% molar solution or tin chloride (SnCl 4 ) in ethyl acetate in an 80% molar solution. This wet chemical spray deposition is carried out at a temperature in the range from 380° C. to 430° C. This layer 36 has a thickness in the range from 300 to 850 Angstroms (preferably 650 to 750 Angstroms). It acts as the primary protective layer for protecting the cell 20 from degradation due to attack from oxidizing agents or from atmospheric pollution, such as sulphur-containing compounds. This semi-conductive "window" layer 36 advantageously acts as a one-way optical mirror. It is transparent for incoming radiation, but it acts as an optical mirror for internal light rays which have been reflected from the back 22 (FIG. 1) for preventing escape of these internal light rays. In addition, this semi-conductive layer 36 advantageously serves as a collection layer in cooperation with the layers beneath it.
A photo litho resist is applied to the rear 22 (FIG. 1) of the cell for masking the regions 54B. Then, the interdigitated n+ type narrow stripes 54A are doped by chemical vapor deposition of phosphorous-containing dopant to a depth of approximately 1.5 microns.
This resist is removed and is applied to the doped stripes 54A, and then the interdigitated p+ type narrow strips 54B are doped by chemical vapor deposition of a boron-containing dopant to a depth of approximately 1.5 microns. These n+ type and p+ type stripes 54A and 54B, respectively, alternate in position in interdigitated relationship as shown in FIG. 1. These narrow interdigitated stripes each have a width in the range of approximately 7 to 15 microns, depending upon their number. There are a plurality of them located between each of the rear contact members 25, for example, in the range from ten to twenty such interdigitated stripes. Eighteen of the are shown in FIG. 1.
Then, the regions 64 near the positions where the rear contact members 25 will be located are protected by a photo litho resist. The first back surface reflector (BSR) mirror layer 56 of tin is plated or applied by metal organic chemical vapor deposition (MOCVD) preferably at least 50 Angstroms thick. On this layer 56 is then applied by plating or MOCVD a chromioum layer 58 forming a second back surface reflector (BSR) having a thickness in the range from 0.5 to 2 microns.
The resist is applied over the second rear surface reflector 58 and is removed from the region where the rear contact member 25 will be located. Each such double BSR 56,58 may, if desired, also be used as charge carrier collection means by electrically connecting the double BSR to the rear contact members 25.
Strike barriers 59 are then deposited by MOCVD in the rear contact regions. Each such barrier is approximately 100 Angstroms thick and approximately 6 microns wide. These strike barriers 59 are formed of titanium nitride and cobalt nitride, at least 90% titanium nitride by weight and in the range of 1% to 10% cobalt nitride by weight of the total composition of the strike barrier. They prevent migration of silver atoms from the contact member 25 into the silicon alloy 51. They reduce the contact resistance and assure good electroplating adhesion of the silver contact layers 33 to be formed. The resist still covers the entire rear 22 of the cell 20 except at the strike barriers 59.
Toward the front of the cell a thin insulating layer 34 less than 15 Angstroms thick of silicon dioxide is formed by chemical vapor deposition. This thin insulating layer 34 electrically insulates the front contact members 27 to be formed from the semi-conductive window and one-way mirror layer 36 described above. This thin layer 34 acts as a tunneling layer for allowing the electrical current carriers to reach the front collection grid contact members 27.
A resist is applied over the layer 34 except in the regions where the front contact members 27 are to be located. Strike barriers 59 are then chemical vapor deposited similar to those on the rear of the cell for the same purposes.
A resist now covers the entire front and rear of the cell except at the strike barriers 59. It is to be understood that these strike barriers 59 are also located in and have the respective widths of the regions where the intermediate bus bars 28, main bus bars 29, and side rail buses 26 will be located.
Silver is then plated onto the strike barriers 59 to a depth of approximately 2 microns. This plated silver forms the front contact members 27, which are approximately 6 microns wide, being spaced apart approximately 151 microns on centers and having a chevron pattern as seen in FIGS. 2, 3 and 4. This plated silver also forms the layers 33 as shown in FIGS. 4, 5, 7 and 8. The silver layer 33 approximately 2 microns thick is also seen in FIG. 1 as the front layer of the rear contacts 25.
A resist is applied over the front contacts 27, and a copper layer 35 (FIGS. 1, 4, 5, 7 and 8) approximately 10 microns thick is then plated over the silver layer 33 for forming the intermediate, main and side rail buses 28, 29 and 26, respectively, and rear contact members 25 (FIG. 1).
A resist is then applied over the intermediate bus 28, and solder 37 is applied by a wave solder application technique to form the solder layer 37 of the main buses 29 and of the side rail buses 26 (FIGS. 5 and 7). This solder layer 37 has a thickness of approximately 20 microns. In order to apply these layers 37, the molten solder bath is vibrationally agitated for forming standing waves on the surface of the molten solder. Then, the copper layers 35 to be plated with solder are positioned above the solder bath, so that these copper layers touch the crests of the standing waves, without immersion of the remainder of the cell 20 into the solder bath.
The resist is then removed from the front and rear of the cell, and the lowest (rear) layer 32 of the anti-reflection-coating (ARC) assembly 39 is applied. This ARC assembly 39 is a three-layer coating, and it is applied over the contact members 27, as seen in FIGS. 1, 4, 5 and 6. This ARC assembly 39 also is applied over the intermediate buses 28, over the main buses 29, and over the side rail buses 26, as seen in FIGS. 4, 5, 7 and 8.
The lowest anti-reflection-coating layer 32 comprises a mixture of cobalt nitride and titanium nitride which is formed by chemical vapor deposition. This layer 32 is less than 100 Angstroms thick, and it cooperates with the transparent mirror-like "window" layer 36 described above for advantageously acting as an internal mirror. This internal mirror advantageously causes radiation in the visible range of the electromagnetic spectrum ("light rays") to be reflected back and forth within the cell between the rear and front of the cell for traversing the light rays multiple times back and forth through the cell for improving the likelihood of photovoltaic interaction between the photons of light and the active photovoltaic regions of this cell.
The middle ARC layer 31 serves to bond the other two ARC layers 30 and 32 together and advantageously acts as a secondary, protective glass-like layer for protecting the photovoltaic cell from degradation due to attack from oxidizing agents or pollutants in the atmosphere. This middle ARC layer 31 is a semi-vitreous glass which advantageously serves also as an encapsulant anti-oxidation protective layer. In addition to protecting the interior of the cell from oxidation, this layer 31 also protects the interior by acting partially as a heat-conducting layer which diminishes and disperses any tendency toward localized heating resulting from non-uniform illumination. Further, this middle layer 31 serves as a semi-vitreous bonding medium for bonding together these three ARC layers 30, 31 and 32 to form the assembly 39.
The middle anti-reflection layer 31 is a light-transparent, semi-vitreous glass composition containing silicon dioxide (SiO 2 ), alumina (Al 2 O 3 ), boron trioxide (B 2 O 3 ), sodium oxide (Na 2 O) and phosphorous pentoxide (P 2 O 5 ). It has a thickness in the range from 50 to 400 Angstroms, the presently preferred thickness being approximately 150 Angstroms. This semi-vitreous glass composition layer 31 contains said ingredients in the following ranges of weight percent of the total composition:
______________________________________ Weight Percent of TotalIngredient Composition______________________________________SiO.sub.2 67 to 82Al.sub.2 O.sub.3 5 to 14B.sub.2 O.sub.3 6 to 18Na.sub.2 O 4 to 20P.sub.2 O.sub.5 0.01 to 5______________________________________
The ratio of SiO 2 to Al 2 O 3 in the composition is in the range from 4.8 to 1 to 16.4 to 1.
An example of the composition of this middle anti-reflection layer 31 which advantageously serves the various functions described above is:
______________________________________ Weight Percent ofIngredient Total Composition______________________________________SiO.sub.2 73Al.sub.2 O.sub.3 7B.sub.2 O.sub.3 10Na.sub.2 O 8.7P.sub.2 O.sub.5 1.3______________________________________
In this example, the ratio of SiO 2 to Al 2 O 3 is 10.4 to 1.
Another example of the composition of this middle anti-reflection layer 31 which advantageously serves the various functions described above is:
______________________________________ Weight Percent ofIngredient Total Composition______________________________________SiO.sub.2 68Al.sub.2 O.sub.3 5B.sub.2 O.sub.3 15Na.sub.2 O 11.2P.sub.2 O.sub.5 9.8______________________________________
In this example the ratio of SiO 2 to Al 2 O 3 is 13.6. The layer 31 is bonded to the front surface of said layer 32 by heating the layer 31 to a temperature of from about 750° C. to a temperature of less than about 850° C.
The front light-transparent ARC layer 30 is markly comprised of silicon dioxide (SiO 2 ) having a thickness in the range from 200 to 650 Angstroms, the presently preferred thickness being approximately 450 Angstroms. It constitutes the top ARC layer, is formed by chemical vapor deposition, and is at the very front of the solar cell 20.
The intermediate bus bars 28 (FIGS. 4 and 7) have a width of approximately 15 microns and a thickness of approximately 12 microns, including a silver layer 33 which is 2 microns thick and a copper layer 35 which is 10 microns thick.
The main bus bars 29 (FIGS. 4 and 5) have a width of approximately 48 microns and a thickness of approximately 32 microns, comprising a silver layer 33 (FIG. 5) which is approximately 2 microns thick, a copper layer 35 which is approximately 10 microns thick and a solder layer 37 which is approximately 20 microns thick.
The side rail buses 26 (FIG. 8) have a width of approximately 96 microns and a thickness of approximately 32 microns, the same as the main buses 29, as seen in FIGS. 5 and 8. The side rail buses 26 have respective silver, copper and solder layers 33, 35 and 37 which are of the same thicknesses as these three respective layers of the main bus 29 (FIG.5).
The region 42 has a resistivity in the range of 0.01 to 0.5 ohm centimeters and preferably has a resistivity of 0.05 ohm centimeters. The region 50 has a resistivity in the range of 0.15 to 1.0 ohm centimeters and preferably has a resistivity in this range and less than 0.5 ohm centimeters.
The regions 49 and 51 (FIG. 1) are each shown in an n+-p-p+ type configuration, but the cell 20 would also be operable with these regions each in p+-n-n+ type configuration. This latter configuration is obtained by interchanging the locations of the phosphorous-containing dopant and boron-containing dopant in FIG. 11.
In forming the cell 20, the laminate 100 (FIG. 10), after rinsing and after passing the guide roller 158, is edge trimmed by laser beams to a width of 10 centimeters. FIG. 8 shows the edge region of the edge-trimmed laminate substrate.
The front contact members 27 in the chevron pattern are spaced 151 microns on centers, and as shown in FIG. 4, extend at an angle of 60° to the intermediate buses 28. The rear contact members 25 (FIG. 1) have a width of approximately 6 microns and a thickness of approximately 12 microns, comprising the layer of silver 33 which is approximately 2 microns thick and the layer of copper 35 which is approximately 10 microns thick. The rear contact members 25 are in a chevron pattern and are also spaced 151 microns on centers. Electrical connection with the rear contact members 25 is made by placing their copper layers 35 against a conductive mount (not shown).
The intermediate bus bars 28 are spaced 0.5 centimeters on centers. The main bus bars 29 are spaced 1.0 centimeters on centers, and they connect at their respective ends with both of the side rail buses 26. These side rail buses 26 extend along opposite edges of the cell 20 which is trimmed to a width of 10 centimeters, as described above, and thus these side rail buses 26 are spaced apart slightly less than 10 centimeters. The cell 20 is a continuous ribbon and can be cut to any desired length for forming an individual photovoltaic cell for a particular application. Electrical connection with the front 21 of the cell 20 is made by a plurality of conductive clamps (not shown) which clamp onto the side rail buses 26 at spaced points along the length of these side rail buses in regions where the ARC layer assembly 39 (FIG. 8) has been removed from these side rail buses.
The ceramic metallic glass semi-conductor alloy compositions of the front region 49 and rear region 51 of the cell 20 enable the respective spectral sensitivities, i.e., the respective band gaps, of these two regions to be individually tailored to the desired frequency ranges of the incident light rays for optimizing the collection efficiency of the cell 20. The preferred band gap for the front cell region 49 is in the range from 1.55 to 1.65 electron volts, and the preferred band gap for the rear cell region 51 is in the range from 0.9 to 1.1 electron volts with these two cell regions operating in series electrically as shown in FIG. 1.
The metalization on the front 21 of the cell provided by the contact members 27 and the intermediate and main buses 28, 29 and the side rail buses 26 enable this cell 20 to be operated at a solar radiation concentration intensity up to 250 suns.
It is to be noted that the metalization on the front 21 including contact members 27, intermediate bus bars 28 and main bus bars 29 is a three-level metalization. When the incident radiation is arriving perpendicular to the front face 21, the shadowing caused by this metalization is less than 5%. In other words, with perpendicular incident light rays the active, unshadowed area of this cell is advantageously more than 95%.
With respect to the light transparent semi-vitreous glass ARC layer 31, the compositions of this layer 31 may include a flux for lowering its melting temperature. Said flux is in an amount less than 20% by weight of the total composition and includes a fluxing compound selected from the group consisting of tin dioxide, antimony dioxide and antimony trioxide. The balance of said total composition of layer 31 is trace elements in an amount less than 2% by weight of the total.
As described above, in the rolling chambers 117, 118, 119 and in the rolling chambers 217, 218, 219 and in the laminating chambers 124, 125, the ceramic metallic glass semi-conductive silicon alloy ribbons 49, 51 and the laminate 100 are preferably heated to be at a level of approximately 20° C. to 60° C. below their semi-liquidus condition. Said alloy advantageously melts in the range of approximately 800° C. to 1,150° C. Thus, the preferred temperature of the silicon alloy in said chambers is in the range from 740° C. to 1,130° C.
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The flexible photovoltaic cell includes thin front and rear junction regions electrically in series each formed of ceramic metallic glass semi-conductor alloys of silicon of approximately zero thermal expansion/contraction coefficient laminated with an intervening semi-conducting layer less than 60 Angstroms thick or an insulating layer less than 20 Angstroms thick. The respective spectral sensitivities of front and rear junction regions are tailored to different frequency ranges. In front are six layers described in sequence rear to front. The lowermost (sixth) is a green/blue semi-insulating cobalt and tin passivating and filter layer less than 10 Angstroms thick. The fifth is a semi-conductive, degradation-protective "window" and one-way mirror for returning back-reflected light. The fourth is an insulating tunneling layer less than 15 Angstroms thick for coupling a front collection grid to the "window". Covering the fourth layer is a triple-layer, anti-reflection coating (ARC) whose middle layer bonds the outer ARC layers and secondarily protects the cell from atmospheric degradation. An internally refelective rear ARC layer cooperates with the "window" for returning back-reflected light. The frontmost ARC layer is mainly comprised of Al 2 O 3 /S i O 2 in the range of 200 to 650 Angstroms thickness. The cell backside is shown having undulations for randomizing reflected light rays. The six front layers effectively adapt the cell for receptivity to solar radiation from about 4,000 to about 12,000 Angstroms, excluding radiation outside thereof, thus accepting 68 percent of solar energy vertically reaching the earth's surface.
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FIELD OF THE INVENTION
The invention relates to the art of papermaking, and particularly to a method for improving paper or paperboard drying without adversely affecting the properties of the paper product.
BACKGROUND
The process of papermaking involves the formation of a web of fibers on a papermachine wire from a slurry of treated wood pulp, water removal from the fibers in the press roll section and in the dryer section of the papermaking machine, and final treatment of the paper by calendaring, chemicals and/or heat. In a typical papermaking process, the web from the press roll section contains about 32 to 35 wt. % solids. The solids may include wood pulp fibers and various additives such as sizing, binders, fillers, pigments and the like. The wet web is then passed through a series of internally heated rolls or steam-filled cylinders whereby the web is dried to about 94% solids content by weight. The number of dryer cylinders is determined by the amount of water to be evaporated based on a typical evaporation rate of about 2 pounds per hour per square foot of total dryer surface.
In the dryer section of the papermachine, water is removed from the web mainly by evaporation. Typically, the wet web is alternately contacted on its opposite sides with a series of hot cylindrical surfaces to heat the web to a temperature whereby water will evaporate from the web to a desired solids content.
Once dried, the paper or paperboard is generally further treated to improve various properties such as smoothness, gloss, wet strength and folding endurance. This subsequent treatment may include adjusting the moisture content of the dried web, densification on high pressure rolls, calendaring and/or heat treating the paper or paperboard product.
Various problems have persisted in the drying of paper webs on large, high-capacity paper machines. For example, drying of paper or paperboard products remains a high energy, capital intensive operation. Hence, the industry is constantly seeking to develop newer and more energy efficient drying techniques. Such drying techniques include high-intensity drying techniques whereby high temperatures and mechanical pressures are applied to the web during drying. Examples of currently used high-intensity drying techniques include press drying, impulse drying, and thermal/vacuum drying. However, the use of high temperature dryers and/or impulse dryers has led to additional problems such as delamination of linerboard products.
Furthermore, in the presently used high-intensity dryers, the paper may shrink by as much as 5 to 6% in the cross direction, i.e. in the direction perpendicular to the direction of travel through the papermaking machine. For wide sheets of paper or paperboard, such a shrinkage rate results in a significant reduction in the overall paper production rate.
Accordingly, even with the new high-intensity drying techniques, there still remains a need to further improve the drying of paper and paperboard products so as to reduce energy costs and reduce paper shrinkage while at the same time not adversely affecting any of the other physical properties of the finished paper or paperboard product.
Uneven drying is another problem which has persisted in drying paper webs. It has been known to apply moisture to portions of a web in the drying section of a paper making machine in order to prevent dry streaks and to assure uniform dryness across the width of the web. The weight and moisture irregularity of the fiber web before drying, irregularities in the heat transfer from the cylinders, edge effects and variations in the ventilation of the papermaking machine all tend to cause nonuniform drying in the cross-direction of the web. Such nonuniformity of drying has a negative effect on paper quality and may also result in increased waste. U.S. Pat. No. 4,378,639 to Walker and U.S. Pat. No. 4,474,643 to Lindblad propose solutions to the problem of uneven drying across the width of the web. These involve the periodic spraying of water on the web in selected areas across the width of the web where low moisture or dry streaks have been detected. Since only the areas of the web requiring moisture adjustment are sprayed, and only when streaking is sensed, the methods do not relate to improvement in the water removal rate.
It is therefore an object of the invention to improve the drying of paper and paperboard products without adversely affecting the physical properties of the finished product.
Another object of the invention is to increase the water removal rate from a paper or paperboard web in the drying portion of a paper and paperboard-making process.
Still another object of the invention is to provide a method for drying paper and paperboard whereby delamination and shrinkage of the paper and paperboard product is reduced.
Other objects and benefits of the invention will be evident from the ensuing discussion and appended claims.
SUMMARY OF THE INVENTION
With regard to the foregoing and other objects, the present invention is directed to an improved drying method for paper and paperboard products. According to its more general aspects, the method comprises drying an elongate paper or paperboard web emerging from the press section of a papermaking machine as it traverses a dryer unit. During the initial drying stages, the web is rewet with an amount of water substantially uniformly across the width of the web when the web has a solids content of no more than about 60 wt. %. The amount of water applied to the web preferably ranges from about 0.5 wt. % to about 10 wt. % based on the total weight of the web including liquid and solids, at each rewet step, most preferably from about 2 to about 6 wt. %, thereby decreasing the solids concentration of the web to about 56 to about 59 wt. %.
While fully rewetting the paper or paperboard web as it dries appears to be the antithesis of the intended objective; i.e., to dry the web, it has been found, quite surprisingly, that full cross-wise rewetting of a drying web when the solids content of the web is in the range of from about 45% to about 85% solids by weight, actually increases the overall rate of water removal as well as reduces the shrinkage rate of the web. Furthermore, the rewetting technique of the invention has been found not to adversely affect any of the other physical properties of the paper or paperboard product.
In another embodiment, the invention provides a method for increasing the drying rate of a paper or paperboard web without adversely affecting physical properties of the paper or paperboard product. The method comprises drying an elongate paper or paperboard web emerging from a press section of a papermaking machine as it traverses a dryer section to a temperature in the range of from about 100° to about 150° C., and continuously rewetting the web with an amount of water substantially uniformly throughout a cross-machine width of the web during an initial web drying stage when the web has a solids content in the range of from about 60 to about 85 wt. %. The amount of water added to the web preferably ranges from about 0.5 wt. % to about 10 wt. % based on the total weight of the web including liquid and solids, at each rewet step.
In yet another embodiment, the invention provides an improved paper or paperboard making process. The process comprises depositing paper or paperboard fibers on a web former screen thereby forming a web. The web is then wet pressed with one or more wet press nips to a solids content in the range of from about 45 to about 65% by weight. Drying of the web takes place on one or more co-rotating heated cylinders of a dryer unit arranged in series so that alternate sides of the web are placed on the cylinder surfaces as the web traverses the dryer unit. As the web is being dried, the web is continuously rewet with an amount of water substantially uniformly across the width of the web during an initial web drying stage, and before the web is dried to a solids content of greater than about 85 wt. %. The amount of water preferably added to the web during rewetting ranges from about 0.5 wt. % pounds to about 10 wt. % based on the total weight of the web including liquid and solids, at each rewet step. The paper or paperboard formed by the foregoing process has been found to have a cross-direction shrinkage rate of less than 2% as compared to greater than about 4 to 10% for conventional drying methods. Furthermore, there is an advantageous increase in the uniformity of the caliper of the web of paper or paperboard in the cross-machine direction by using the rewetting techniques of the invention.
SUMMARY OF THE DRAWINGS
FIG. 1 is an illustration, not to scale, of a device used to simulate impulse drying of paper and paperboard products.
FIGS. 2-4 are graphic representations of the drying rates of the rewet webs of this invention compared to conventionally dried webs.
DETAILED DESCRIPTION OF THE INVENTION
A key feature of the invention is the uniform widthwise continuous rewetting of an elongate paper or paperboard web in the drying section of a papermaking machine before the solids content of the web reaches a level of greater than about 85 wt. %. The process of the invention not only increase the drying rate of the web, but also improves one or more of the physical properties of the final paper or paperboard product. Accordingly, the cross directional shrinkage of the paper or paperboard product may be reduced by using the rewetting technique of the invention. Furthermore, the density, tensile strength compression and caliper uniformity in the cross-machine direction of the finished product may be increased. When preparing laminated products such as linerboard, the technique may also decrease the occurrence of delamination.
To perform the methods of the invention, paper or paperboard fibers are first deposited on a web former screen such as a Fourdrinier wire so as to form a web which is dewatered from an initial consistency (% solids) of 1 to 4 wt. % to 15 to 20 wt. % solids as it leaves the web forming end of the wire. Next, the web is pressed under pressure by the use of one or more nip rolls to increase the solids content of the web to about 45 to 50 wt. %.
Once it leaves the wet press rolls, the web is typically fed to the dryer section of the papermaking machine containing one or more stacked, co-rotating steam heated cylinders or rolls. The web traverses the cylinder stacks in an S-fashion at high speeds alternately exposing opposite faces of the web to the hot cylinder surface. Certain sections of the drying unit may include a continuous felt web for pressing the paper web against the cylinder surfaces.
When the solids content of the web is in the range of from about 45 to about 60 wt. %, the web is continuously uniformly rewet across the entire cross-machine width of the web so as to decrease the solids content of the web to between about 40 and about 59 wt. %. Drying continues during and after rewetting by contacting the web with additional heated cylinders. When the solids content of the web is in the range of from about 60 to about 63 wt. %, the web may be continuously uniformly rewet a second time across its width so as to decrease the solids content of the web to between about 53 and about 62 wt. %.
The sequence of rewetting and drying of the web is preferably repeated when the solids content of the web is in the range of from about 65 to about 68 wt. %, in the range of from about 70 to about 75 wt. % and in the range of from about 80 to about 85 wt. %. Each time the web is rewet, from about 0.5 wt. % to about 10 wt. % of water is preferably added to the web. Although five web rewetting cycles have been described, any number of web rewetting and drying cycles (more or less than 5) may be used provided the web is rewet at least once before the solids content of the web reaches about 85 wt. %. Furthermore, for different paper or paperboard products, some optimization of the web rewetting and drying procedure may be in order so as to achieve the most benefit from the methods of the invention.
As noted above, it is believed to be critical that the web is rewet at least once during the initial web drying stages before the solids content reaches about 85 wt. %. While not desiring to be bound by theoretical considerations, it is believed that rewetting the web at this critical time during the web drying sequence according to the invention may actually increase the rate of water removal from the web. In general, a web dries from the hot surface contact side of the web to the open air surface side of the web. As the web dries there is believed to be an advancing intermediate drying zone between the dry zone of the web material and the wet zone of the web material. The intermediate zone advances from the dry zone adjacent the hot surface contact side of the web to the open surface side of the web. In the dry zone of the web, most of the heat transferred from the hot surface of the dryer to the water contained in the intermediate and wet zones of the web is by convection. In the intermediate zone, water vaporizes and the vapors .flow into the wet zone of the web where the water vapor recondenses. In the wet zone of the web the heat transfer is mainly by conduction through the water in the web. Based on the above theoretical model of a web during drying, there may be both convective heat transfer and conductive heat transfer taking place in the intermediate zone of the web. Some energy is therefore expended vaporizing water in the intermediate zone of the web rather than conducting heat to the wet zone of the web whereby water can be removed by vaporization at the open surface of the web.
In accordance with the invention, when the zone adjacent the hot surface is rewet the amount of water evaporated in the intermediate zone may be reduced or eliminated. Accordingly, the heat from the hot contact surface of the web may be transferred by conduction through all zones of the web rather than by convection in the dry zone and convection and/or conduction in the intermediate zone of the web. The invention, therefore, is believed to reduce the amount of energy expended vaporizing water in the intermediate zone of the web and thus utilize more of the available heat energy to dry the web. Furthermore, there is less buildup of vapor in the web during drying and hence less chance for delamination of the plies of a multi-ply web.
An unexpected benefit of the process of the invention is the substantial reduction in the shrinkage rate of the web. Webs which are continuously rewet before the web reaches a solids content of about 85 wt. % exhibit a shrinkage rate of less than about 2% whereas a shrinkage rate of about 4 to about 10 is typical with conventional drying techniques.
In order to effectively rewet the web, a water spray, steam shower or moisture laden moving felt belt in contact with the web may be used to add sufficient moisture to the web. Water sprays, steam showers or moisture laden felt belts are well known in the art for spraying a web to control streaking and for other intermittent uses to address-non-uniformities in the dried web. See for example U.S. Pat. No. 2,661,669 to Friedrich, Jr.; U.S. Pat. No. 3,037,706 to Dupasquier; U.S. Pat. No. 3,838,000 to Urbas; U.S. Pat. Nos. 3,948,721 and 4,915,788 to Winheim; U.S. Pat. No. 4,207,143 to Glomb, et al.; U.S. Pat. No. 4,253,247 to Bergstrom; U.S. Pat. Nos. 4,358,900 and 4,444,622 to Dove; U.S. Pat. No. 4,378,639 to Walker; U.S. Pat. No. 4,474,643 to Lindblad; U.S. Pat. Nos. 4,543,737 and 4,977,687 to Boissevain; U.S. Pat. No. 4,596,632 to Goetz, et al.; U.S. Pat. No. 4,685,221 to Taylor, et al.; and U.S. Pat. No. 4,765,067 to Taylor incorporated herein by reference as if fully set forth. Unlike the above patents, however, the web is sprayed with a water mist fully across its width using a bank of sprayers or a wetted felt blanket on a continuous basis to decrease the solids content of the web to the desired degree before the solids content reaches about 85 wt. %. One or both sides of the web may be rewet by the foregoing procedures.
There is no particularly critical design for the web rewetting mechanism of the invention. Accordingly, water sprays of well known design may be added to existing or new drying equipment in order to rewet the web when the web reaches the preferred solids contents, or additional equipment may be added to existing or new drying equipment. Regardless of the dryer design, it is preferred to rewet the web or felt at a nip roll in order to insure more even distribution of the water on the web. The nip pressure may be provided solely by the weight of the nip roll, preferably a long, heated nip roll. Where practical, it is preferred to rewet the web directly rather than wetting a felt for contact with the web.
The water used to increase the moisture content of the paper or paperboard product need not be any particular temperature or quality. However, where there is concern for build-up of scale on the dryer cylinders, it may be desirable to use distilled or boiler feed water. The water sources not only include pure water, but may also include aqueous solutions or dispersions of coatings or additives normally used in the papermaking process. The water to be sprayed on the web may be at or below room temperature or the water may be at an elevated temperature.
As noted above, the web is preferably rewet a plurality of times during the drying procedure. For thicker web material, more rewetting and dryer cylinders may be required. For thinner web material, fewer cycles of rewetting and fewer dryer cylinders may be required. Those skilled in the art can readily determine the optimum number of rewetting and dryer cylinders for any given paper or paperboard product by conducting a few simple tests.
In order to further illustrate the advantages of the above described invention, the following non-limiting examples are given.
Example 1
In a series of drying experiments, three inch by three inch squares of 42 lbs/MSF paperboard were used. These samples were preconditioned to an initial solids content of about 30 wt. %. A Dynamic Compression Tester illustrated in FIG. 1 was used for all of the experiments.
With reference to FIG. 1, the three inch square web of paperboard 8 was placed on a three inch square felt pad 10 both of which were place on the cold plate 6 of the compression tester. To simulate impulse drying conditions, the hot plate 4 of the compression tester, at a temperature of 150° to 155° C., was pressed against the web 8 and felt pad 10 for 4 milliseconds at a pressure of 100 to 130 psig. (690 to 900 kPa). The results of simulated impulse drying of the web are given in Table 1 for control samples 1, 2 and 3 and rewet samples 4, 5, and 6. The samples were rewet by spraying water on the samples until the liquid content of the samples increased about 2 to about 17 wt. %, representing a decrease in the solids percent of about 2 to 16 wt. %. Samples 4-6 were each rewet three times during the drying procedure. Once the samples reached about 90 wt. % solids, the sheets were removed from the compression tester and dried in a laboratory flat plate drier for further physical analysis.
TABLE 1______________________________________Test No. of Solids (wt. %) Solids IncreaseSheet Presses (Init.-Fin.) (wt. % per press)______________________________________Control 1 26 31-94 2.4Control 2 22 31-74 2.0Control 3 28 30-74 2.1Sample 4 8 30-48 2.0rewet 7 46-62 2.3rewet 6 57-74 2.8rewet 7 72-84 1.7avg. -- -- 2.3Sample 5 8 31-66 4.4rewet 5 60-80 4.0rewet 5 63-84 4.2rewet 5 79-91 2.4avg. -- -- 3.5Sample 6 9 31-57 2.9rewet 5 53-68 3.0rewet 5 57-74 3.4rewet 7 68-83 2.1avg. -- -- 2.8______________________________________
FIGS. 2-4 are graphical representations of the web drying characteristics of rewet samples 4, 5 and 6 and control samples 1, 2, and 3. In all of the figures, the rewet samples reached a higher percent solids sooner than did the control samples.
In the following Table 2, the average physical properties of control samples 1 and 2 were compared with the average physical properties of rewet samples 4 and 5.
TABLE 2______________________________________ Control Rewet Change Samples Samples (%)______________________________________Basis Weight 227.3 246.2 --(g/in.sup.2)Caliper 17.38 17.96 --(0.001 inch)Scott Bond 73.2 90.5 23.6(ft/lb) × 10.sup.3Density 0.52 0.53 --(g/cm.sup.3)STFI 19.2 21.9 14.0(lbf/in)Tensile 45.8 49.4 7.8(lb/in)MOE 96.7 117.8 21.8(lb/in.sup.2) × 10.sup.3______________________________________
In the foregoing table, the following standard methods of the Technical Association of the Pulp and Paper Industry (TAPPI) were used:
______________________________________Test TAPPI No.______________________________________Density T220Basis Weight T220Caliper T411Tensile T494MOE T494Scott Internal Bond UM402STFI (Svenska Traforskningsinstitutet)Standard Compression (edge-wise) Test from SwedishForest Products Research Labs, Stockholm______________________________________
Example 2
In a series of samples, multi-ply board was pressed using the general procedure described in Example 1 above. The surface properties of the rewet samples of multi-ply board were compared with the unpressed samples, samples which were pressed at room temperature, and samples which were hot pressed but not rewetted. Rewetting of the samples was accomplished by spraying water onto the surface of the dry samples until the whole surface was wet in appearance. The hot press used to dry the samples was set at a pressure of 150 psig (1034 kPa), a temperature of 204° C. and a press time of 50 milliseconds. Results of the foregoing treatment are given in Tables 3, 4, and 5.
TABLE 3______________________________________Parker Roughness at 10 kgf/sq cmTreatment Sample Sample SampleDescription 1 2 3______________________________________A No treatment 9.58 9.64 9.50B Room Temperature 9.57 9.48 9.39 Press (twice)C Hot Press (twice), 8.71 -- -- No rewetD Hot Press (twice), 6.44 6.64 7.11 No rewet-- Change in Samples 33 31 25 A to D (%)______________________________________
TABLE 4______________________________________Sheffield RoughnessTreatment Sample Sample SampleDescription 1 2 3______________________________________A No treatment 343 360 355B Room Temperature 352 358 349 Press (twice)C Hot Press (twice), 287 -- -- No rewetD Hot Press (twice), 345 329 315 With rewet-- Change in Samples 0 9 11 A to D (%)______________________________________
TABLE 5______________________________________GE BrightnessTreatment Sample Sample SampleDescription 1 2 3______________________________________A No treatment 74.1 72.6 65.3B Room Temperature 74.2 72.5 65.3 Press (twice)C Hot Press 74.0 -- -- (twice), No rewetD Hot Press 73.6 72.1 65.2 (twice), With rewet-- Change in 0 0 0 Samples A to D (%)______________________________________
With reference to Tables 3-5, it appears that the Parker Print roughness improves considerably with rewetting followed by hot pressing, whereas the Sheffield smoothness is less affected and rewetting appears to have no effect on the brightness. The rewet and pressed samples also exhibited a shrinkage of less than about 2% whereas the hot pressed samples which were not rewet had a shrinkage of 5 to 6%.
Having thus described the invention and its preferred embodiments, it will be recognized that variations of the invention are within the spirit and scope of the appended claims.
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The specification discloses an improved method for drying a paper or paperboard web emerging from the press section of a papermaking machine as it traverses a dryer unit. The method comprises continuously rewetting the web across its width during the initial web drying stage when the web has a solids content of no more than about 65 wt. %. The method improves the water removal rate and decreases the shrinkage rate of the web during drying.
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CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation patent application of application Ser. No. 11/761,483 filed Jun. 12, 2007 now U.S. Pat. No. 7,600,510, currently allowed, which was a continuation-in-part of application Ser. No. 10/951,128 filed Sep. 27, 2004, which issued on Jul. 24, 2007 as U.S. Pat. No. 7,246,614, the entire contents of which are incorporated herein by reference.
BACKGROUND AND SUMMARY OF THE INVENTION
1. Technical Field
The invention is a small, lightweight, portable cooking stove that uses alcohol as fuel.
2. Prior Art
Portable cooking stoves designed to use alcohol as a fuel are well known to prior art. These are used by hikers, campers, backpackers, hunters and others who have a need to boil water or cook a hot meal in remote locations or primitive conditions. As a fuel, alcohol has various advantages over petroleum based fuels. Alcohol is widely available, inexpensive, convenient, relatively innocuous and easy to handle. It can be readily repackaged and safely carried in lightweight plastic bottles. Alcohol stoves are typically smaller and lighter than petroleum-fueled stoves. Alcohol stoves are typically also very simple, reliable and easy to use, and have few, if any, moving parts. Because of these advantages, alcohol-fueled stoves are very popular in many parts of the world. However, in the United States they have had limited popularity. This limited popularity is primarily due to two factors.
The first factor that has limited the popularity of alcohol-fueled stoves in the United States is their overall poor performance. Under the best conditions, the heat output from these stoves is marginal. In real outdoor conditions of wind and weather, these stoves rapidly become incapable of cooking a meal. These stoves demonstrate a variety of forms and features that cause inefficient performance and wasted heat. The overall inefficient performance of alcohol stoves known to prior art also causes an excessive consumption of fuel. This is undesirable both due to the increased cost of operating the stove, as well as the increased weight of fuel that must be carried.
The second factor that has limited the popularity of alcohol-fueled stoves in the United States is the inability to effectively adjust the heat output of the stove. Often these stoves provide no manner of heat adjustment. When they do, it is commonly effected by means of some type of snuffer in the form of a partial lid, cap or cover that is positioned in such a way that partially interferes with or throttles the flame. This method of adjusting the heat output has several disadvantages. Positioning or adjusting of the snuffer can be a rather awkward undertaking and requires removing the cooking pot or reaching under it. This presents a danger of burning or scalding. Often the cooking pot must be completely removed from the stove and set aside while positioning the snuffer. Obstructing the flame in this way tends to produce a small hot spot on the bottom of the cooking pan and prevents the even distribution of heat for thorough and rapid cooking.
In summation, the two primary factors that have limited the popularity of alcohol stoves in the United States are their overall poor performance and the inconvenience with which the heat adjustment is effected. Similarly, petroleum-fueled stoves enjoy a broad popularity primarily due to their advantages of high heat output and the ability to adjust this heat output for control of the cooking process. These advantages are generally viewed as outweighing their numerous disadvantages. The disadvantages include the need for bulky and heavy metal fuel containers, high operating cost, poor operation in wind or cold weather, need to constantly tend them during cooking, odor, danger of fuel spills, complexity, poor reliability, the need to carry maintenance kits, and the possibility of dangerous flare-ups when lighting the stove. In light of these numerous disadvantages, the importance of high heat output and adjustable cooking performance in determining the overall utility and popularity of a stove is clearly seen.
SUMMARY IF THE CURRENT INVENTION
The current invention seeks to achieve a variety of improvements over the portable cooking stoves which are known to prior art. The current invention is conceived and designed with the intent of achieving specific objectives for enhanced performance and convenience over the prior art.
It is an objective of this invention to achieve a high heat output and stable cooking performance suitable for fast and effective cooking in a variety of outdoor conditions of wind and weather—attaining overall cooking performance which consistently meets or exceeds the performance of petroleum-fueled stoves.
It is a further objective of this invention to achieve a high fuel efficiency, in order to minimize operating costs and the weight of fuel that must be carried.
It is a further objective of this invention to provide a convenient and simple means for adjusting the heat output of the stove to effectively control the cooking process.
It is a further objective of this invention to be small, lightweight and conveniently portable. When packed with a fuel bottle, the entire stove shall be of a size that can be held in the palm of the hand and weigh only a few ounces. The entire invention is rendered conveniently portable in a sturdy and compact package.
It is a further objective of this invention to be largely trouble free, simple, reliable and easy to use.
It is a further objective of this invention that it will cool quickly so that it can be handled and stowed soon after use.
To achieve the above listed objectives, a portable cooking stove is described wherein the several components of the stove are adapted to perform together as an integrated unit—all components being engineered to operate in balanced synergy to maximize the overall performance and utility of the stove. The several components of the stove are adapted to work in concert to optimize as far as practicable the various fluidic, thermodynamic and heat transfer processes of the stove in a manner that is both unobvious and unknown to prior art.
Combustion Chamber
Stoves known to the prior art are typically intended to effect the combustion process in the open air. Because the combustion process takes place in the open air, there is no means for controlling the quantity of air in contact with the combustion process. This produces a condition known in the field of thermodynamics as “excess air”. The condition of excess air occurs when a combustion process is provided with more air than is required for the complete combustion of the fuel. This excess air removes heat from the combustion process, thereby reducing the efficiency of the combustion process.
The importance and benefits of providing a combustion chamber to create a controlled volume wherein the entire combustion process can be enclosed, contained and encompassed in order to maximize the heat output of a cooking stove are well known and detailed in prior art. U.S. Pat. Nos. 5,915,371 and 5,842,463 both describe the functioning and the performance benefits derived from the use of a combustion chamber to maximize the heat output of a cooking stove. These inventions even describe a means for adjusting the draft to alter the airflow through the combustion chamber, thereby varying the heat output and adapting to various cooking requirements.
These inventions describe combustion chambers that are intended to be used primarily with solid fuel, such as wood or charcoal. They are adapted to address the specific problems associated with the combustion of such solid fuels. These inventions are not engineered nor adapted to meter and direct the flow of combustion air to efficiently mix with and effect the combustion of a vaporized fuel. These prior inventions do not conceive of the combustion chamber as integral with a specific combustion source, such that both components might be optimized and adapted to operate in balanced synergy. The cooking stove of the current invention incorporates a combustion chamber that is specifically engineered and adapted as a component within an integrated assembly, to meter and direct the flow of combustion air such that it efficiently mixes with and effects the combustion of a vaporized fuel.
The portable, alcohol-fueled cooking stove of the current invention comprises a combustion chamber which is engineered and adapted to create a controlled volume wherein the entire combustion process can be enclosed, contained and encompassed. The purpose of this combustion chamber is to meter, regulate and control the flow of combustion air, as well as facilitating and promoting the mixing of the combustion air with the vaporized fuel. The combustion chamber is adapted to specifically meter and direct the flow of combustion air so as to maintain the stoichiometric ratio with a given quantity of fuel and optimize the efficiency of the combustion process.
Alcohol-fueled stoves known to prior art may optionally employ a windscreen which may encompass the stove to a greater or lesser extent. However, these windscreens are, by design, description and intent, adapted only to shield the stove from the deleterious effects of crosswinds. Unlike a true combustion chamber, these windscreens are not engineered, adapted nor intended to create a controlled volume wherein the entire combustion process can be contained, regulated and optimized. The prior art does not consider these windscreens to be an integral part of the stove. The prior art consistently refers to these windscreens as ancillary components, being separate from the stove proper—an optional piece to be employed as required to shelter the stove. These windscreens are not intended to be fundamental to the operation of the stove and are not adapted to specifically meter and direct the flow of combustion air so as to optimize the efficiency and control the combustion process.
Fuel Vaporizer
Whereas the combustion chamber is designed to effectively meter and control the flow of combustion air, the efficient operation of the stove also relies on the effective generation and distribution of fuel vapor. The respective volumes of the combustion air and the fuel vapor must be adapted to alternately achieve a stoichiometric ratio of air to fuel for maximum combustion efficiency, or a rarified ratio of air to fuel for reduced heat output and control over the cooking process.
In order for alcohol fuel to burn, the liquid must be converted into a vapor. Consequently, all alcohol-fueled stoves employ some means by which the liquid alcohol fuel can be vaporized. This typically takes the form of some manner of vessel containing liquid alcohol fuel which is caused to be heated and thereby be converted to vapor. Alternately, some form of wick is used to effect the vaporization of the fuel. The efficiency and rate at which the liquid fuel can be vaporized directly affects both the fuel consumption and the heat output of the stove. Stoves known to prior art do not effect the fuel vaporizing process efficiently and demonstrate excessive thermal losses. These excessive thermal losses serve to both reduce the heat output of the stove, as well as increase the fuel consumption.
The inefficiency of the fuel vaporizing process of stoves known to prior art is caused by several factors. These fuel vaporizing devices typically incorporate an excessive external surface area, both as a consequence of their physical size and dimensions, as well as the deliberate application of fins, ribs or other heat transferring features. This excessive surface area causes the loss of heat to the environment primarily through convection. These fuel vaporizing devices typically incorporate an excessive mass as a consequence of their physical size and dimensions, as well as deliberate application of additional mass. This excessive mass causes the loss of heat to the thermal mass of the fuel vaporizing device. These deliberate applications of excessive surface area and excessive mass result from an improper understanding of the physical processes involved in the fuel vaporization. U.S. Pat. No. 4,164,930 clearly illustrates both of these impediments applied to prior art.
Many stoves known to prior art use some form of wick. The employment of a wick significantly circumscribes the performance of the fuel vaporizer. The limited capacity of the wicking process, combined with both the mass and volume of the wick material, render the use of a wick unsuitable where high heat output, small size and light weight are all required.
In addition to incorporating forms and features that are conducive to the excess loss of heat, stoves known to prior art typically do not employ an effective means for mixing the vaporized fuel thoroughly with the combustion air. If the fuel vapor and combustion air are not thoroughly mixed in the proper area beneath the cooking pot, unburned fuel vapor will escape and both the temperature and efficiency of the combustion process will be reduced. To effectively mix the combustion air and fuel vapor it is necessary to induce turbulence in one or both of the fluids. For maximum combustion efficiency, this turbulence must be created at the confluence of the two fluid flows.
The portable, alcohol-fueled cooking stove of the current invention comprises a fuel vaporizer which is engineered and adapted to minimize the heat lost through the external surface area and mass as far as practicable while maintaining the utility of the stove.
The volume of the vessel is specifically adapted to hold approximately two U.S. fluid ounces of fuel. This is the optimal fuel capacity of the fuel vaporizer. This limited volume enables the fuel vaporizer to have minimal size and dimensions. This minimal size and dimensions reduce as far as practicable both the thermal mass and external surface area of the fuel vaporizer. This minimizes the heat which is lost to the thermal mass and the external surface area of the fuel vaporizer, and provides the maximum amount of energy available to effect the vaporization of the liquid fuel. At the same time two U.S. fluid ounces of fuel provides fuel sufficient enough to cook a typical meal for two people. By holding no more fuel than is required to cook a meal, the thermal mass of the fuel is also minimized. This minimal fuel volume and thermal mass reduces as far as practicable the heat lost to the thermal mass of the fuel. Consequently, the optimized size and dimensions of the fuel vaporizer enable complete utility of the stove while minimizing heat loss.
The fuel vaporizer is also designed to accelerate the flow of the fuel vapor to induce a turbulent flow. By throttling the expanding vapor through an array of small orifices, jets of vapor are ejected from the fuel vaporizer. These jets are positioned and located so as to be injected directly into the convective flow of the combustion air. This maximizes the interaction and mixing between the combustion air and the fuel vapor and creates a very efficient diffusion flame.
Adjustable Heat Output
In addition to achieving a high efficiency with the consequent advantages of high, stable heat output and low fuel consumption, the current invention also incorporates a means for simply and conveniently adjusting the heat output to achieve effective and precise control over the cooking process. This heat adjustment is achieved by metering and controlling the flow of combustion air within the combustion chamber. The flow of combustion air is controlled both in volume and location within the combustion chamber.
The ability to control the cooking process by adjusting the heat output of a stove is a primary attribute that defines the utility, convenience and desirability of the stove. Without the facility for effectively adjusting the heat output, a stove is of limited utility and largely unsuitable for cooking. Petroleum-fueled stoves effect the heat adjustment by directly throttling the fuel flow. This in turn reduces the quantity of combustion air which is entrained by the fuel flow.
Alcohol-fueled stoves known to prior art often incorporate no means at all for adjusting the heat output. Those stoves which do provide a heat adjustment typically employ some type of snuffer in the form of a partial lid, cap or cover that is positioned in such a way to obstruct or interfere with the flow of fuel vapor as it escapes from the fuel vaporizer. This method of adjusting the heat output has several disadvantages. Positioning or adjustment of the snuffer can be a rather awkward undertaking and requires removing the cooking pot or reaching under it. This presents a danger of burning or scalding. Often the cooking pot must be completely removed from the stove and set aside while placing the snuffer. Obstructing the flame in this way also tends to produce a small hot spot on the bottom of the cooking pan and prevents the even distribution of heat for thorough and rapid cooking.
The portable, alcohol-fueled cooking stove of the current invention incorporates a practical, convenient, safe and simple mechanism for regulating the heat output of the stove. This mechanism is quick and easy to operate, and it achieves an effective control of the cooking process. This mechanism is integral with the stove and readily accessible on the outside of the stove. The heat output of the stove can be precisely adjusted without removing the cooking pot or risking burns, scalds or other mishaps.
This adjustment of the heat output is effected by metering and controlling the flow of combustion air both in volume and in location. This metering and controlling of the combustion air flow modulates the combustion process which is in contact with the fuel vaporizer, enabling the temperature of the fuel vaporizer to be regulated. That is, by reducing the volume and redirecting the location of the combustion air within the combustion chamber the fuel vaporizer can be caused to be cooled. As the fuel vaporizer is cooled, it generates less fuel vapor. This reduced flow of fuel vapor, being conditioned by and adapted to the reduced and redirected flow of combustion air, produces a lower overall heat output for the stove. This means of reducing the flow of fuel vapor, in concert with the reduced and redirected flow of the combustion air, allows an effective, convenient and precise control of the cooking process. This means of controlling the heat output also spreads the heat very evenly throughout the top portion of the combustion chamber and around the bottom and the sides of the cooking pot, enabling foods to be cooked quickly and thoroughly without hot spots or burning.
Portability
In addition to the improvements in the heat output, efficiency, utility and convenience of the current invention, it is also adapted to be small, lightweight and easily portable. The various components are engineered as an integrated unit not only to facilitate the operation of the stove, but also to facilitate its portability and storage.
An important measure of the utility of a backpacking stove is how lightweight, simple and convenient it is to carry. Stoves known to prior art may typically consist of a half-dozen or more parts, with little thought given to their packaging. This can render them bulky and difficult to carry, with the potential for lost or damaged parts and added complexity of setup.
All the components of the current invention nest together when packed, forming a single, compact unit in the shape of a hollow cylinder. This cylinder is proportioned to also contain a fuel bottle, whereby the entire invention is rendered conveniently portable in a sturdy and compact package that weighs only a few ounces and can be comfortably held in the palm of the hand. This package is so efficient that when the fuel bottle is filled with fuel, less than ten percent of the package contains empty space. Being so contained in a single, integrated unit, all of the components are protected from loss or damage, and the stove can be quickly unpacked and set up for use.
BRIEF DESCRIPTION OF THE DRAWINGS
A more complete understanding of the present invention may be had by reference to the following Detailed Description when taken in connection with the accompanying Drawings, wherein:
FIG. 1 shows the preferred embodiment in a cutaway, elevation view of the assembled stove;
FIG. 2 shows the preferred embodiment in a plan view of the assembled stove;
FIG. 3 shows the preferred embodiment of the fuel vaporizer in a perspective view;
FIG. 4 shows the preferred embodiment in sectional elevation with the stove in use and configured to produce maximum heat output;
FIG. 5 shows the preferred embodiment in sectional elevation with the stove in use and configured to produce minimum heat output;
FIG. 6 shows the preferred embodiment in a cutaway, elevation view of the packed stove;
FIG. 7 shows the preferred embodiment in an exploded, perspective view of the packed stove;
FIG. 8 shows an alternate embodiment of the fuel vaporizer in a plan view;
FIG. 9 shows this alternate embodiment of the fuel vaporizer in a cutaway, sectional elevation view;
FIG. 10 shows this alternate embodiment of the fuel vaporizer in a perspective view;
FIG. 11 shows this alternate embodiment of the fuel vaporizer in sectional elevation when it is in use;
FIG. 12 shows an additional alternate embodiment of the fuel vaporizer in a plan view;
FIG. 13 shows this additional alternate embodiment of the fuel vaporizer in a perspective view;
FIG. 14 shows this additional embodiment of the fuel vaporizer in a cutaway, elevation view;
FIG. 15 shows an additional alternate embodiment of the fuel vaporizer in a perspective view;
FIG. 16 shows this additional alternate embodiment of the fuel vaporizer in a cutaway, sectional elevation view;
FIG. 17 shows an additional alternate embodiment of the fuel vaporizer and obturating device in a perspective view;
FIG. 18 shows this additional alternate embodiment of the fuel vaporizer and obturating device in a sectional, elevation view;
FIG. 19 shows this additional alternate embodiment of the fuel vaporizer and obturating device in a plan view;
FIG. 20 shows this additional alternate embodiment of the fuel vaporizer and obturating device in an elevation view;
FIG. 21 shows an alternate embodiment of the combustion chamber and obturating device in a plan view;
FIG. 22 shows an additional alternate embodiment of the combustion chamber and obturating device in a plan view;
FIG. 23 shows an additional alternate embodiment of the combustion chamber and obturating device in a cutaway, elevation view;
FIG. 24 shows an additional alternate embodiment of the combustion chamber and obturating device in a cutaway, elevation view;
FIG. 25 shows an additional alternate embodiment of the combustion chamber and obturating device in a cutaway, elevation view, with the obturating device positioned to produce minimum heat output;
FIG. 26 shows this additional alternate embodiment of the combustion chamber and obturating device in a cutaway, elevation view, with the obturating device positioned to produce maximum heat output;
FIG. 27 shows an alternate embodiment of the assembled stove in a plan view;
FIG. 28 shows this additional alternate embodiment of the assembled stove in a cutaway, elevation view;
FIG. 29 shows an additional alternate embodiment of the fuel vaporizer and obturating device in a plan view; and
FIG. 30 shows this additional alternate embodiment of the fuel vaporizer and obturating device in a cutaway, sectional elevation view.
N.B.: The material thicknesses of components shown in section in these drawings are approximately ten-thousandths of one inch. Consequently, the section thicknesses are shown in slightly exaggerated scale to identify the sections.
DETAILED DESCRIPTION
FIG. 1 shows a cutaway, elevation view of the preferred embodiment of the assembled stove. FIG. 2 shows a plan view of the preferred embodiment of the assembled stove. FIG. 3 shows a perspective view of the preferred embodiment of the fuel vaporizer.
The preferred embodiment of the current invention includes a combustion chamber 101 which comprises a cylindrical wall 1 approximately six inches in diameter and four inches in height. This cylindrical wall 1 is formed from a thin sheet of aluminum, approximately ten-thousandths of one inch thick, being rolled into a cylinder and attached together at the ends 17 . The ends 17 are attached by means of rivets 15 that slide into keyhole slots 16 . The combustion chamber 101 is intended to alternately sit upon a base or a supporting surface 99 such that the bottom of the combustion chamber is fully closed and sealed off from the air.
The combustion chamber cylindrical wall 1 is perforated by a plurality of circular ports 13 and 14 . These ports 13 and 14 admit combustion air into the combustion chamber 101 and meter and direct the flow of this combustion air. These ports 13 and 14 which perforate the combustion chamber wall 1 are arrayed in two sets.
The first set of ports 13 which perforates the combustion chamber wall 1 is the primary set of air metering ports 13 . There are eighteen ports in the primary set of air metering ports 13 . Each of the eighteen ports in the primary set 13 is one-half inch in diameter. All of the ports of the primary set 13 are coplanar and are arrayed angularly about the combustion chamber cylindrical wall 1 , being located approximately one-half inch above the bottom edge of the combustion chamber 101 . Under the influence of the natural convection currents resulting from the combustion process, the primary set of ports 13 is adapted to meter the appropriate volume of air to form a stoichiometric ratio with a specific quantity of fuel vapor. The locations and positions of the primary air metering ports 13 are adapted to provide a controlled and directed flow of combustion air to efficiently mix with and effect the combustion of the fuel vapor.
The second set of ports 14 which perforates the combustion chamber wall 1 is the secondary set of air metering ports 14 . There are six ports in the secondary set of air metering ports 14 . Each of the six ports in the secondary set 14 is one-quarter inch in diameter. All of the ports of the secondary set are coplanar and arrayed angularly about the combustion chamber cylindrical wall 1 , being located approximately two and one-quarter inches above the bottom of the combustion chamber 101 . The ports of the secondary set 14 are intended to throttle and restrict the flow of air into the combustion chamber, thereby rarifying the quantity of combustion air within the combustion chamber.
The combustion chamber 101 includes an obturating device 2 whereby alternately either the primary set of air metering ports 13 , or the secondary set of air metering ports 14 may be blocked off in part or in whole. By alternately blocking either the primary set 13 or the secondary set 14 of air metering ports, both the volume and the flow patterns of the combustion air within the combustion chamber can be regulated and controlled. By controlling both the volume and flow patterns of the combustion air, the heat output and cooking performance of the stove can be controlled and adjusted.
The obturating device 2 consists of a thin, strong, flexible strip of aluminum approximately ten-thousandths of one inch thick and one and one-quarter inches wide. This aluminum strip is formed into a cylindrical band by attaching the ends of the strip together. The ends of the strip are attached by means of a rivet 15 that slides into a keyhole slot. The cylindrical obturating band 2 thus formed has an inside diameter adapted to fit over the outside diameter of the combustion chamber cylindrical wall 1 . The diameter of the obturating band 2 is adapted to fit securely over the combustion chamber cylindrical wall 1 , while being loose enough to be readily slid over the combustion chamber cylindrical wall 1 .
The combustion chamber 101 includes a means for supporting a cooking pot 7 . This pot supporting device comprises two steel rods 3 , each rod 3 being approximately five and one-half inches long and one-eighth inch in diameter. Both ends of each rod 3 pass through the combustion chamber cylindrical wall 1 and are supported by the cylindrical wall 1 . The rods 3 are arranged parallel and coplanar, being spaced approximately three inches apart. Being so arranged, the rods 3 form a rudimentary grillage upon which a cooking pot 7 may be supported. This grillage is positioned approximately one inch down from the top of the combustion chamber 101 .
In conjunction with the combustion chamber 101 , the stove comprises a fuel vaporizer 104 such that the combustion chamber 101 and fuel vaporizer 104 are engineered and adapted as an integrated unit—operating in balanced synergy to effect a high heat output and fuel efficiency by maintaining a stoichiometric ratio between the combustion air and fuel.
The fuel vaporizer 104 comprises a vessel fabricated from aluminum in the shape of a shallow, cylindrical cup 4 . This shallow, cylindrical, cup-shaped, aluminum vessel 4 is approximately two inches in diameter and is adapted to hold approximately two U.S. fluid ounces of fuel.
This shallow, cylindrical cup 4 includes a double wall 8 . By means of this double wall 8 the interior volume of the shallow, cylindrical cup 4 is divided into two chambers 10 and 11 . The first chamber is an inner chamber 11 . The inner chamber 11 forms a cylinder whose diameter is defined by the inside diameter of the double wall 8 . This cylindrical, inner chamber 11 is coaxial and concentric with the shallow, cylindrical cup 4 . The second chamber is an outer chamber 10 . The outer chamber 10 is annular in form, this annulus being formed by the gap between the outer wall of the combustion chamber 101 and the double wall 8 . The outer, annular chamber 10 fully encircles the inner cylindrical chamber 11 . Said chambers are separated each from the other by the double wall 8 . The chambers have some connection and may enjoy limited intercourse by means of a plurality of small ports 9 at the base of the double wall 8 .
The inner, cylindrical chamber 11 has a diameter that is at least eighty percent of the overall diameter of the fuel vaporizer 104 . This maximizes, as far as is practicable while maintaining the utility of the stove, the outside surface area of the inner, cylindrical chamber 11 . This also minimizes, as far as is practicable while maintaining the utility of the stove, the thickness of the outer, annular chamber 10 . These factors work together to maximize the rate of heat transfer and the efficiency of heat transfer between the inner, cylindrical chamber 11 and the outer, annular chamber 10 .
The inner, cylindrical chamber 11 of the fuel vaporizer 104 is uncovered at the top, thereby forming an open chamber. The contents of this open, inner chamber 11 may freely communicate with the air. The outer, annular chamber 10 is covered at the top, thereby forming a closed chamber. This closure is interrupted only by a plurality of small orifices 12 . There are approximately twenty two of these orifices 12 arrayed in a circular pattern. These orifices 12 are approximately twenty eight-thousandths of one inch in diameter. The diameter of the circular pattern of these orifices 12 is approximately one-eighth of an inch smaller than the overall diameter of the fuel vaporizer 104 .
FIG. 4 shows a section through the elevation view of the stove as it is set up for cooking use and configured for maximum heat output. A cooking pot 7 is shown placed upon the stove, being supported by the pot supporting rods 3 . The cooking pot 7 has an outer diameter which is somewhat smaller than the inner diameter of the combustion chamber 101 such that the cooking pot 7 is able to fit inside the combustion chamber 101 . The diameter of the cooking pot 7 is approximately five and five-eighths inches. When the cooking pot 7 is seated upon the pot supporting rods 3 and located within the top of the combustion chamber 101 , the top of the combustion chamber 101 is, for most of its area, obstructed and closed off by the cooking pot 7 . The only opening of the top of the combustion chamber 101 is an annular gap which exists between the cooking pot 7 and the combustion chamber wall 1 . This annular gap has a width of about three-sixteenths of one inch. This annular gap acts as a flue and accelerates the combustion gases out of the top of the combustion chamber 101 . This greatly facilitates and strengthens the natural convection process that draws air into the combustion chamber through the air metering ports 13 and 14 . This annular gap also increases the transfer of heat from the combustion gases to the cooking pot 7 . As the combustion gases are accelerated through the annular gap, they give up heat to the cooking pot 7 as defined by the Bernoulli Principle.
With the stove set up as shown in FIG. 4 , the combustion chamber 101 creates a controlled volume wherein the entire combustion process can be enclosed, contained and encompassed. The combustion chamber 101 is placed upon some supporting surface or suitable base 99 such that the bottom of the combustion chamber 101 is fully closed off from intruding airflow. The obturating band 2 of the combustion chamber 101 is positioned to fully expose the primary set of air metering ports 13 , thereby occluding the secondary set of air metering ports 14 . Alcohol fuel 28 is poured into the inner, cylindrical chamber 11 of the fuel vaporizer 104 . By means of the plurality of small ports 9 at the base of the double wall 8 , the fuel flows into the outer, annular chamber 10 and seeks a common level within the inner chamber 11 and outer chamber 10 . The fuel vaporizer 104 is placed in the center of the combustion chamber 101 , being set upon the same supporting surface or suitable base 99 that supports the combustion chamber 101 . A cooking pot 7 is placed on the stove, obstructing the top of the combustion chamber 101 except for the annular flue which exists between the cooking pot 7 and the combustion chamber wall 1 . The alcohol fuel 28 in the inner, cylindrical chamber 11 of the fuel vaporizer 104 is ignited and combusts by virtue of its free communication with the air.
The combustion of the fuel 28 in the inner, cylindrical chamber 11 causes the double wall 8 of the fuel vaporizer 104 to be heated. The heating of the double wall 8 causes heat to be conducted into the outer, annular chamber 10 of the fuel vaporizer 104 . This heat causes the fuel in the outer, annular chamber 10 to vaporize. Because the geometry of the fuel vaporizer 104 is so adapted to maximize the flow of heat from the inner chamber 11 to the outer chamber 10 and minimize the loss of heat from the exterior surface area and thermal mass, the rate of fuel vaporization in the outer, annular chamber 10 is maximized. The vaporized fuel can only escape from the outer, annular chamber 10 via the plurality of small orifices 12 which interrupt the top closure of the outer, annular chamber 10 .
In passing through the plurality of small orifices 12 , the fuel vapor is accelerated such that jets of fuel vapor 26 are ejected from the fuel vaporizer 104 . By virtue of their location along the top edge of the outer diameter of the fuel vaporizer 104 , the jets of fuel vapor 26 are ejected directly into the upwelling convection current of combustion air 30 which has been metered and directed by the combustion chamber 101 through the primary set of air metering ports 13 . This forceful convergence of the fuel vapor 26 and combustion air 30 produces effective mixing of the fuel and air and creates a hot, efficient diffusion flame—the design and dimensions of the fuel vaporizer 104 and the combustion chamber 101 being so adapted to operate together in balanced synergy and produce a stoichiometric ratio of fuel and air. The combustion gases are directed against the bottom and around the sides of the cooking pot 7 to maximize heat transfer to the cooking pot 7 . In this manner the cooking performance, heat output and fuel efficiency of the stove are maximized.
Notwithstanding the employment illustrated in FIG. 4 , where both the heat output and the efficiency of the stove are maximized, the stove can be easily adjusted to reduce the heat output in order to effectively and conveniently control the cooking process. FIG. 5 shows a section through the elevation view of the stove as it is set up for cooking use and configured for minimum heat output. A cooking pot 7 is shown placed upon the stove, being supported by the pot supporting rods 3 . To adjust the heat output of the stove, the obturating band 2 is slid down to cover and block the primary set of air metering ports 13 . With the obturating band 2 fully occluding the primary set of air metering ports 13 , the secondary set of ports 14 is fully exposed. With the obturating band 2 in this position, the primary set of air metering ports 13 is blocked, such that no air can enter the bottom half of the combustion chamber 101 . This creates an anaerobic atmosphere in the bottom half of the combustion chamber 101 . The absence of oxygen in this anaerobic zone prevents combustion from occurring in and about the fuel vaporizer 104 . Being physically removed from, and beneath, the combustion process 27 , the fuel vaporizer 104 is caused to be cooled, thereby reducing the rate of vapor generation and altering the flow pattern of fuel vapor. The quantity of fuel vapor is thereby adapted to, and conditioned by, the reduced volume and redirected flow of combustion air.
The fuel vapor diffuses into the top half of the combustion chamber 101 , where it opportunistically mixes with oxygen in this rarified top zone. This forms a diverse and dynamic combustion process 27 which puts out a reduced amount of heat while spreading out within the top of the combustion chamber 101 . This eliminates hot spots which impair the utility of a stove. In this manner a practical, simple and effective control is achieved over the heat output, the shape and location of the cooking flame, and the overall cooking performance of the stove. This control is also very convenient and easy to use, as the obturating band 2 is readily accessible on the outside of the combustion chamber 101 . Adjusting the obturating band 2 can be accomplished without interference or removal of the cooking pot 7 simply by tapping it lightly to cause it to slide down and cover the primary set of air metering ports 13 .
Consequently, the control of the stove is such that when the primary set of air metering ports 13 is exposed there is the maximum output of heat from the stove. Simply by sliding the obturating band 2 down to cover the primary set of ports 13 , the secondary set of ports 14 is opened and the heat is quickly controlled and reduced. The primary set of ports 13 might alternately be partially unblocked, allowing small quantities of air into the bottom of the combustion chamber 101 . This provides effective and practical control over a range of heat outputs for improved cooking performance.
FIG. 6 shows a cutaway, elevation view of the packed stove. FIG. 7 shows a perspective, exploded view of the packed stove. These figures illustrate how the stove is conceived as an integrated unit for packing and carrying. The cylindrical wall 1 of the combustion chamber 101 is formed from a thin, aluminum sheet which is attached together at its ends 17 . The ends of this sheet can be unattached and the thin, aluminum sheet is sufficiently strong and flexible to be wrapped into a coil around the cylindrical fuel vaporizer 104 . Likewise, the obturating band 2 of the combustion chamber 101 is formed from a thin, aluminum strip which is attached together at its ends. The ends of this strip can be unattached and the thin, aluminum band 2 is sufficiently strong and flexible to be wrapped into a coil around the coiled combustion chamber wall 1 . The assemblage thereby constructed is in the form of a hollow cylinder approximately two and one-quarter inches in diameter and four inches in length.
This hollow cylinder is of sufficient diameter and sufficient length to efficiently contain a four fluid ounce fuel bottle 5 , four fluid ounces being sufficient volume of fuel for several days hiking. The cap 6 of the fuel bottle 5 is of such size and geometry as to fit efficiently inside the fuel vaporizer 104 . The pot supporting rods 3 store alongside this cylindrical assemblage. Thus the entire invention is rendered conveniently portable in a sturdy, lightweight and compact package which is completely self contained, comprising the entire stove and the fuel bottle. This package fits in the palm of the hand and weighs only a few ounces.
FIG. 8 shows a plan view of an alternate embodiment of the fuel vaporizer 131 . FIG. 9 shows a cutaway elevation view of this alternate embodiment fuel vaporizer 131 , and FIG. 10 shows a perspective view. The alternate embodiment of the fuel vaporizer 131 is adapted to concentrate a large amount of heat on a small, confined chamber 34 . The alternate embodiment fuel vaporizer 131 also surrounds and envelopes this small, confined chamber 34 in such a way that very little heat can escape from it. In this way the alternate embodiment of the fuel vaporizer 131 is capable of achieving a high rate of fuel vaporization with the concatenate effect of a high overall heat output for the stove. The alternate embodiment fuel vaporizer 131 is potentially capable of even greater heat output than the preferred embodiment 104 of the fuel vaporizer.
The alternate embodiment of the fuel vaporizer 131 comprises a vessel in the shape of a shallow, cylindrical cup 31 . This shallow, cylindrical cup 31 incorporates a double wall 32 . By means of this double wall 32 the interior volume of the shallow, cylindrical cup 31 is divided into two chambers 33 and 34 . The first chamber 34 is an inner chamber. The inner chamber 34 forms a cylinder whose diameter is defined by the inside diameter of the double wall 32 . This cylindrical, inner chamber 34 is coaxial and concentric with the shallow, cylindrical cup 31 . The second chamber 33 is an outer chamber. The outer chamber 33 is annular in form, this annulus being formed by the gap between the cylindrical cup 31 and the double wall 32 . The outer, annular chamber 33 fully encircles the inner, cylindrical chamber 34 . Said chambers 33 and 34 are separated by the double wall 32 . The inner and outer chambers 33 and 34 have some connection and may enjoy limited intercourse by means of a plurality of small ports 35 at the base of the double wall 32 .
The outer, annular chamber 33 is open, being uncovered at the top, thereby forming an open chamber. The contents of this open, outer, annular chamber 33 may freely communicate with the air. The inner, cylindrical chamber 34 is closed, being covered at the top, thereby forming a closed chamber. This closure 41 is interrupted only by a plurality of small apertures 40 . This plurality of small apertures 40 is arrayed radially and angularly about the top closure 41 of the inner, cylindrical chamber 34 .
FIG. 11 shows a section view of the fuel vaporizer 131 in use. When the stove is in use, alcohol fuel 28 is poured into the outer, annular chamber 33 of the fuel vaporizer 131 . By means of the plurality of small ports 35 at the base of the double wall 32 , the fuel flows into the inner, cylindrical chamber 34 and seeks a common level within the inner chamber 34 and the outer chamber 33 . The alcohol fuel 28 in the outer, annular chamber 33 of the fuel vaporizer 131 is ignited and causes combustion 38 by virtue of its free communication with the air.
The combustion 38 of the fuel 28 in the outer, annular chamber 33 causes the double wall 32 of the fuel vaporizer 131 to be heated. Because of this heating action accomplished in the outer, annular chamber 33 , this outer, annular chamber 33 can be referred to as the heating chamber. The heating of the double wall 32 causes heat to be conducted into the inner, cylindrical chamber 34 of the fuel vaporizer 131 . This heat causes the fuel 28 in the inner, cylindrical chamber 34 to vaporize. Because of this vaporizing action accomplished in the inner, cylindrical chamber 34 , this inner, cylindrical chamber 34 can be referred to as the vaporizing chamber. The vaporized fuel can only escape from the inner, cylindrical, vaporizing chamber 34 via the plurality of small apertures 40 which interrupt the top closure 41 of the inner, cylindrical, vaporizing chamber 34 . As the fuel vapor escapes through this plurality of small apertures 40 , it is accelerated into jets 39 thereby entraining and actively mixing with the combustion air.
The alternate embodiment 131 shares various features with the preferred embodiment fuel vaporizer 104 of the fuel vaporizer, as well as employing important differences. Both embodiments of the fuel vaporizer comprise two, concentric, interconnected chambers separated by a double wall. Both embodiments of the fuel vaporizer employ one open chamber to generate heat by means of open combustion. Both embodiments of the fuel vaporizer employ one closed chamber to generate vaporized fuel and accelerate this vapor into jets.
The essential difference between the preferred and alternate embodiments of the fuel vaporizer is the reversal in the function of the inner and outer chambers. The preferred embodiment fuel vaporizer 104 is adapted to nest efficiently with the other components so that the stove can be stowed in a single, compact unit. This requirement dictates certain aspects of the preferred embodiment fuel vaporizer's 104 form, geometry and dimensions. These dictated aspects of the preferred embodiment fuel vaporizer's 104 form, geometry and dimensions necessitate certain compromises that preclude the total optimization of the fuel vaporizer's performance. The primary compromise involves the heat which is lost from the outer, annular vaporizing chamber 10 through the outside wall of the fuel vaporizer 104 .
The alternate embodiment fuel vaporizer 131 is engineered specifically to maximize the rate of fuel vaporization and the heat output of the stove. The form and geometry of the alternate embodiment are not constrained by packaging requirements or other such limitations. This frees the alternate embodiment fuel vaporizer 131 to be fully optimized for heat output and fuel efficiency. By engulfing the inner, cylindrical vaporizing chamber 34 in combustion 38 , its form and design are adapted to minimize heat loss and produce the highest possible temperatures to vaporize and superheat the fuel 28 . By providing the outer, annular heating chamber 33 with an outer perimeter, more oxygen is available for the combustion process 38 therein. These adaptations enable the alternate embodiment fuel vaporizer 131 to achieve the highest efficiency and heat output.
FIG. 12 shows a plan view of an alternate embodiment of the fuel vaporizer 135 . FIG. 13 shows a perspective view of this alternate embodiment 135 , and FIG. 14 shows a cutaway, sectional elevation view. The alternate embodiment of the fuel vaporizer 135 is provided with cylindrical duct 42 coaxial with the body of the fuel vaporizer. This cylindrical duct 42 extends thru the bottom of the fuel vaporizer and has a height about equal to that of the fuel vaporizer 135 . This cylindrical duct 42 is adapted to provide a source of combustion air to the inner, annular chamber 48 of the fuel vaporizer 135 . By providing combustion air to the inner, annular chamber 48 , a greater amount of heat can be generated in the inner, annular chamber 48 . In this way the alternate embodiment of the fuel vaporizer 135 is capable of achieving a high rate of fuel vaporization with the concatenate effect of a high overall heat output for the stove. The alternate embodiment 135 is potentially capable of even greater heat output than the preferred embodiment 104 of the fuel vaporizer.
The alternate embodiment 135 shares various features with the preferred embodiment 104 of the fuel vaporizer, and operates in a similar manner. The alternate embodiment of the fuel vaporizer 135 comprises a vessel in the shape of a shallow, cylindrical cup 45 . This shallow, cylindrical cup 45 incorporates a double wall 44 . By means of this double wall 44 the interior volume of the shallow, cylindrical cup 45 is divided into two chambers 47 and 48 . The first chamber 48 is an inner chamber. The inner chamber 48 comprises an annular volume whose inside diameter is defined by the outside diameter of the cylindrical duct 42 , and whose outside diameter is defined by the inside diameter of the double wall 44 . This annular, inner chamber 48 is coaxial and concentric with the shallow, cylindrical cup 45 . The second chamber 47 is an outer chamber. The outer chamber 47 is annular in form, this annulus being formed by the gap between the cylindrical cup 45 and the double wall 44 . The outer, annular chamber 47 fully encircles the inner, annular chamber 48 . Said chambers 47 , 48 are separated by the double wall 44 . The inner and outer chambers 47 , 48 have some connection and may enjoy limited intercourse by means of a plurality of small ports 46 at the base of the double wall 44 .
The outer, annular chamber 47 is closed, being covered at the top, thereby forming a closed chamber. This closure is interrupted only by a plurality of small apertures 43 . The inner, annular chamber 48 is open, being uncovered at the top, thereby forming an open chamber. The contents of this open, inner, annular chamber 48 may freely communicate with the air. The contents of this open, inner, annular chamber 48 are directly provided with a supply of combustion air thru the cylindrical duct 42 .
FIG. 15 shows a perspective view of an alternate embodiment of the fuel vaporizer 140 . FIG. 16 shows a cutaway, sectional elevation view of this alternate embodiment 140 . The alternate embodiment of the fuel vaporizer 140 is provided with cylindrical duct 53 coaxial with the body of the fuel vaporizer. This cylindrical duct 53 extends thru the center of the fuel vaporizer 140 . This cylindrical duct 53 is adapted to provide a source of combustion air to the center of the fuel vaporizer 140 . By providing combustion air to the center of the fuel vaporizer 140 , complete combustion of the vaporized fuel can be effected.
The alternate embodiment 140 shares various features with the alternate embodiment 131 of the fuel vaporizer, and operates in a similar manner. The alternate embodiment of the fuel vaporizer 140 comprises a vessel in the shape of a shallow, cylindrical cup 49 . This shallow, cylindrical cup 49 incorporates a double wall 50 . By means of this double wall 50 the interior volume of the shallow, cylindrical cup 49 is divided into two chambers 54 , 55 . Chamber 55 is an inner chamber. The inner chamber 55 comprises an annular volume whose inside diameter is defined by the outside diameter of the cylindrical duct 53 , and whose outside diameter is defined by the inside diameter of the double wall 50 . This annular, inner chamber 55 is coaxial and concentric with the shallow, cylindrical cup 49 . The second chamber 54 is an outer chamber. The outer chamber 54 is annular in form, this annulus being formed by the gap between the cylindrical cup 49 and the double wall 50 . The outer, annular chamber 54 fully encircles the inner, annular chamber 55 . Said chambers 54 , 55 are separated by the double wall 50 . The outer and inner chambers 54 , 55 have some connection and may enjoy limited intercourse by means of a plurality of small ports 56 at the base of the double wall 50 .
The inner, annular chamber 55 is closed, being covered at the top by a cover 51 , thereby forming a closed chamber. This cover 51 is interrupted only by a plurality of small apertures 52 . The outer, annular chamber 54 is open, being uncovered at the top, thereby forming an open chamber.
Additional Alternate Embodiment of the Fuel Vaporizer
FIG. 17 shows a perspective view of an alternate embodiment of the fuel vaporizer 145 . FIG. 18 shows a sectional elevation view of this alternate embodiment 145 . FIG. 19 shows a plan view and 20 shows an elevation view of this alternate embodiment 145 . The alternate embodiment of the fuel vaporizer 145 is provided with cylindrical duct 64 coaxial with the body of the fuel vaporizer. This cylindrical duct 64 extends thru the center of the fuel vaporizer 145 . This cylindrical duct 64 is adapted to provide a source of combustion air to the center of the fuel vaporizer 145 . By providing combustion air to the center of the fuel vaporizer 145 , complete combustion of the vaporized fuel can be effected.
The alternate embodiment 145 shares various features with the alternate embodiment 140 of the fuel vaporizer, and operates in a similar manner. The alternate embodiment of the fuel vaporizer 145 comprises a vessel in the shape of a shallow, cylindrical cup 60 . This shallow, cylindrical cup 60 incorporates a conical wall 58 . By means of this conical wall 58 the interior volume of the shallow, cylindrical cup 60 is divided into two chambers 68 , 69 . Chamber 69 is an inner chamber. The inner chamber 69 comprises a substantially annular volume whose inside diameter is defined by the outside diameter of the cylindrical duct 64 , and whose outside surface is defined by the inside surface of the conical wall 58 . This substantially annular, inner chamber 69 is coaxial and concentric with the shallow, cylindrical cup 60 . The second chamber 68 is an outer chamber. The outer chamber 68 is substantially annular in form, being formed by the gap between the cylindrical cup 60 and the conical wall 58 . The outer, substantially annular chamber 68 fully encircles the inner, substantially annular chamber 69 . Said chambers 68 , 69 are separated by the cylindrical wall 58 . The outer and inner chambers 68 , 69 have some connection and may enjoy limited intercourse by means of a plurality of small ports 57 at the base of the cylindrical wall 58 .
The inner, substantially annular chamber 69 is closed, being covered at the top by a cover 59 , thereby forming a closed chamber. This closure is interrupted only by a plurality of small apertures 63 . The outer, substantially annular chamber 68 is partially covered by an obturating device 62 . This obturating device 62 is slidably mounted on the outside of the shallow cup 60 by means of the cylindrical collar 61 . The cylindrical collar 61 is actuated by means of a Scotch Yoke mechanism 65 , 66 , 67 . Rotating the rod 67 about its axis causes the levers 66 to engage the pins 65 , alternately causing the pins to be raised or lowered. The pins 65 are affixed to the cylindrical collar 61 . By means of this slidable mounting, the obturating device 62 can be raised or lowered over the chamber 68 . With the obturating device 62 in the raised position, the chamber 68 is substantially open to the air, allowing combustion to occur in the chamber 68 . With the obturating device in the lowered position, the chamber 68 is closed, extinguishing combustion in the chamber 68 . By so regulating the combustion in the chamber 68 , the overall heat output of the fuel vaporizer can be controlled.
FIG. 29 shows a plan view of an alternate embodiment of the fuel vaporizer 180 . FIG. 30 shows a cutaway, sectional elevation view of this alternate embodiment 180 . The alternate embodiment 180 shares various features with the alternate embodiments 140 and 145 of the fuel vaporizer, and operates in a similar manner. The alternate embodiment of the fuel vaporizer 180 is provided with cylindrical duct 97 coaxial with the body of the fuel vaporizer. This cylindrical duct 97 extends thru the center of the fuel vaporizer 180 . This cylindrical duct 97 is adapted to provide a source of combustion air to the center of the fuel vaporizer 180 . By providing combustion air to the center of the fuel vaporizer 180 , complete combustion of the vaporized fuel can be effected.
The alternate embodiment of the fuel vaporizer 180 comprises a vessel in the shape of a shallow, cylindrical cup 91 . This shallow, cylindrical cup 91 comprises a double wall 98 . By means of this double wall 98 the interior volume of the shallow, cylindrical cup 91 is divided into two chambers. The cup 91 incorporates a plurality of ports 95 , which perforate the outer wall of the cup 91 . The fuel vaporizer 180 comprises an obturating device 92 in the shape of an inverted, shallow, cylindrical cup, which is rotatably mounted around the outside cylindrical wall of the shallow, cylindrical cup 91 . The obturating device is so dimensioned to create an annular gap 93 between the edge of the obturating device 92 and the double wall 98 . The obturating device 92 incorporates a plurality of ports 94 which perforate the outer cylindrical wall of the obturating device 92 . These ports 94 of the obturating device 92 are executed such that they can be aligned with the ports 95 of the shallow cylindrical cup 91 , thereby opening the ports 95 . Alternately, these ports 94 can be misaligned with the ports 95 , by means of a rotational displacement of the obturating device 92 . Ports 94 and ports 95 being so misaligned, thereby cause ports 95 to be closed. The rotational displacement of the obturating device is facilitated by the tab 96 . By so aligning the ports 94 and ports 95 combustion in the outer chamber can be regulated, whereby the overall heat output of the fuel vaporizer can be controlled.
FIG. 21 shows a plan view of an alternate embodiment of the combustion chamber 150 . This alternate embodiment comprises a combustion chamber 69 and an obturating device 70 which possess an elliptical planform.
FIG. 22 shows a plan view of an alternate embodiment of the combustion chamber 155 . This alternate embodiment comprises a combustion chamber 71 and an obturating device 72 which possess a rectangular planform.
FIG. 23 shows an elevation view of an alternate embodiment of the combustion chamber 160 . This alternate embodiment comprises a combustion chamber 73 having a primary set of air metering ports 76 which is effected as a pattern of numerous small ports. The secondary set of air metering ports 75 , is also effected as a pattern of small ports.
FIG. 24 shows an elevation view of an alternate embodiment of the combustion chamber 165 . This alternate embodiment comprises a combustion chamber 77 having a primary set of air metering ports 80 which is effected as a series of elongated slots. The secondary set of air metering ports 79 is also effected as a pattern of elongated slots.
FIGS. 25 and 26 show elevation views of an alternate embodiment of the combustion chamber and obturating device 170 . This alternate embodiment comprises an obturating device 82 which is rotatably mounted on the outside of the combustion chamber 81 . The obturating device 82 incorporates a primary set of air metering ports 83 and a secondary set of air metering ports 85 . The combustion chamber 81 incorporates a primary set of air metering ports 84 and a secondary set of air metering ports 86 . The primary ports 83 of the obturating device 82 coincide with the primary ports 84 of the combustion chamber 81 . The secondary ports 85 of the obturating device 82 coincide with the secondary ports 86 of the combustion chamber 81 . The primary ports 83 of the obturating device 82 are angularly offset from the secondary ports 85 , with respect to the corresponding ports 84 , 86 of the combustion chamber 81 .
FIG. 25 shows the obturating device 82 rotatably positioned to close off the primary ports 84 of the combustion chamber 81 . In this position the secondary ports 86 of the combustion chamber 81 are opened.
FIG. 26 shows the obturating device 82 rotatably positioned to close off the secondary ports 86 of the combustion chamber 81 . In this position the primary ports 84 of the combustion chamber 81 are opened.
FIG. 27 shows a plan view of an alternate embodiment of the cooking stove 175 . FIG. 28 shows a cutaway, elevation view of the alternate embodiment of the cooking stove 175 . This alternate embodiment comprises a combustion chamber 88 . The combustion chamber 88 is full encircled by a cylindrical wall 87 . The cylindrical wall 87 has a diameter somewhat greater than the diameter of the combustion chamber 88 , such that an annular gap exists between the outside diameter of the combustion chamber 88 and the inside diameter of the cylindrical wall 87 . The cylindrical wall 87 is intended to alternately sit upon a base or a supporting surface such that the bottom of the cylindrical wall 87 is fully closed and sealed off from the air. The bottom of the combustion chamber 88 is raised above the bottom above of the cylindrical wall 87 , forming a gap which leaves the bottom of the combustion chamber 88 open.
The cooking stove 175 comprises the fuel vaporizer 145 . The fuel vaporizer 145 is supported at the bottom of the combustion chamber 88 by means of two supports 90 and the rod 67 which pass thru openings in the cylindrical wall 87 . The combustion chamber 88 sits upon the supports 90 and the rod 67 . In this way the fuel vaporizer 145 , the combustion chamber 88 , and the cylindrical wall 87 form an integrated assembly of the cooking stove 175 .
In operation, combustion air is drawn down thru the annular gap between the combustion chamber 88 and the cylindrical wall 87 . This arrangement of the combustion chamber 88 and the cylindrical wall 87 creates a heat exchanger that preheats the combustion air as it is draw thru the annular gap. The preheated combustion air enters into the combustion chamber 88 thru the open bottom, where it mixes with the vaporized fuel generated by the fuel vaporizer 145 and combusts. The heat output of the stove can be adjusted by moving the obturating device 62 , by means of rotating the rod 67 which is accessible on the outside of the cylindrical wall 87 .
This embodiment of the stove could alternately comprise the fuel vaporizer 180 in place of the fuel vaporizer 145 , and still maintain the same principles, function and operation.
It can be seen that the portable, alcohol-fueled cooking stove of the current invention is novel in that it employs a combustion chamber designed to create a controlled volume wherein the entire combustion process can be enclosed, contained and encompassed, thereby regulating and controlling the flow and mixing of the combustion air with the vaporized fuel. This combustion chamber is engineered and adapted to work in balanced synergy with a fuel vaporizer. In combination, these components operate to maintain a stoichiometric ratio of air and fuel to effect a very efficient and high temperature combustion process. This high heat output and balanced combustion also produce stable performance across a wide range of operating conditions and variations of wind and weather. This employment of a combustion chamber and a fuel vaporizer engineered as a unit operating in balanced synergy to maximize the efficiency, temperature and stability of the combustion and cooking processes is both insightful and unknown to prior art.
It can be further seen that the portable, alcohol-fueled cooking stove of the current invention is novel in that it employs a fuel vaporizer engineered to minimize the loss of energy in the fuel vaporizing process as far as practicable, while maintaining the utility of the stove. This is achieved through minimizing the external surface area and mass of the fuel vaporizer through improvements in the geometry, design and configuration of the fuel vaporizer, while providing optimized fuel capacity for convenient cooking. These improvements in the geometry, design and configuration of the fuel vaporizer produce a significant and measurable increase in the efficiency of the fuel vaporizing process. These improvements in the geometry, design and configuration of the fuel vaporizer, which produce a significant and measurable increase in the efficiency of the fuel vaporizing process, are persistently absent from the prior art.
It can be further seen that the portable, alcohol-fueled cooking stove of the current invention is novel in that it employs a combustion chamber which is provided with a plurality of air metering ports. In conjunction with these air metering ports, the combustion chamber employs an obturating device whereby various of the ports might be alternately blocked or unblocked in order to meter and regulate the volume, flow and location of the combustion air within the combustion chamber. By means of this metering, directing and regulating of the combustion air, the fuel vaporizer can be caused to be cooled, thereby reducing the rate of vapor generation and altering the flow pattern of fuel vapor. In this manner a practical, simple and effective control is achieved over the heat output, the shape and location of the cooking flame, and the overall cooking performance of the stove. This method of control causes the heat to be spread evenly throughout the top portion of the combustion chamber, resulting in a uniform cooking temperature and preventing hot spots that can scorch or burn food. This method of regulating the cooking performance of the stove by means of controlling the volume, flow and location of the combustion air, with the concatenate effect of cooling the fuel vaporizer and reducing the flow of fuel vapor, is deviceful and unique.
It can be further seen that the portable, alcohol-fueled cooking stove of the current invention is novel in that it is conceived as an integrated unit for packing and carrying. The various components of the stove nest together when packed, forming a compact, sturdy unit in the shape of a hollow cylinder, which is also proportioned to contain a fuel bottle. Being thus packed, the entire stove, including fuel, forms a tightly integrated assembly which fits in the palm of the hand and weighs only a few ounces. So efficient is this nesting of components, that when packed with a full fuel bottle the stove has over ninety percent of its volume filled. Such an efficient nesting of the various components of the stove, with the inclusion of the fuel bottle, into a single, compact and sturdy unit is inventive and imaginative.
In addition to the specific features, adaptations and forms that render the current invention both novel and an unobvious improvement over prior art, there is a further, compelling testament to the innovation of the current invention. Alcohol-fueled cooking stoves for backpacking and camping are currently available in well over a dozen forms, designs and concepts—either commercially or through published “Do-It-Yourself” instructions. The current invention exhibits a significantly higher heat output, as measured objectively by the time required to boil a given quantity of water, than any currently published performance specifications for any alcohol-fueled backpacking stove. The stove of the current invention exhibits significantly lower fuel consumption, as measured objectively by the fuel required to boil a given quantity of water, than any currently published performance specifications for any alcohol-fueled backpacking stove.
In addition to the significant and measurable improvements in heat output and fuel efficiency of the current invention when compared to other alcohol-fueled stoves known to prior art, there is a further, prevailing testament to the ingenuity and improvement of the current invention. The performance of the current invention has been tested in a variety of operating conditions against petroleum-fueled backpacking stoves. The current invention consistently meets or exceeds the overall cooking performance of petroleum-fueled stoves, as measured objectively by the total time required to cook a typical, prepackaged, two serving meal of rice. The current invention consistently meets or exceeds the fuel efficiency of petroleum-fueled stoves, as measured objectively by the gross weight of fuel required to cook a typical, prepackaged, two serving meal of rice. The current invention also exhibits superior high altitude and cold weather performance than many petroleum-fueled stoves.
It can be seen that the alternate embodiment of the fuel vaporizer is novel in that the inner, cylindrical, vaporizing chamber is fully encircled by the outer, annular, heating chamber. This configuration causes a greater amount of heat to be concentrated in the inner, cylindrical, vaporizing chamber effecting a high rate of fuel vaporization and high heat output. This adaptation of a fuel vaporizer having two, interconnected chambers whereby the inner, cylindrical, vaporizing chamber is fully encircled by the outer, annular, heating chamber enables levels of convenience, safety and performance which are unknown to prior art.
It must be noted that a superficially similar device is known to prior art. This superficially similar device is known from published specifications to produce a greater heat output when compared to other configurations of alcohol stoves known to prior art. However, the current invention differs fundamentally from the prior art and is a significant improvement over the prior art.
Whereas the current invention employs a single vessel that comprises two, interconnected chambers, the superficially similar device known to prior art employs two, separate vessels. The primary vessel is the vaporizing vessel. This vessel is substantially closed except for a plurality of small apertures and a filling port whereby the vessel is provided with fuel. This filling port is subsequently plugged and the vessel is caused to be heated, whereby the fuel inside the vessel is vaporized and escapes through the plurality of small apertures. The second vessel is employed to heat the primary, vaporizing vessel. The second vessel is in the form of a small tray or saucer. The primary, vaporizing vessel is placed in this small tray or saucer shaped vessel and fuel is poured into this tray or saucer shaped vessel. The combustion of the fuel in this tray or saucer shaped vessel provides the heat for vaporizing the fuel in the primary, vaporizing chamber.
The use of two, separate vessels causes this superficially similar device to be both inconvenient and dangerous. The need to fill two, separate vessels is cumbersome and leads to spillage of fuel. Filling the vaporizing vessel through a small filling port requires the use of a funnel or similar device. In addition, the fuel must be premeasured as the fuel level cannot be seen inside the vessel. The plug for the filling port can be lost, rendering the stove inoperable. Alternately, the vaporizing vessel may have a separate lid which must be removed for filling. This separate lid is inconvenient and cumbersome with the potential to be lost or damaged, rendering the stove inoperable. Finally, as the vaporizing vessel is substantially closed except for the plurality of small apertures, the vaporizing vessel can be overheated and present an explosion hazard.
The current invention, being a single vessel comprising two, interconnected chambers, corrects all of the above shortcomings. Fuel is conveniently poured into the open, outer, annular chamber where its level can be easily seen. Graduations may be provided on the side of the vessel to accurately display the fuel volume. No plugs, funnels or other loose pieces are required. Most important, the inner, vaporizing chamber cannot be overpressurized and cannot explode. As the inner, vaporizing chamber enjoys intercourse with the open, outer annular chamber by means of a plurality of small apertures at the base of the double wall, if the pressure in the vaporizing chamber becomes too high, it simply displaces liquid fuel and escapes harmlessly. The employment of two interconnected chambers in a single vessel, with the concomitant improvements in the convenience, utility and safety of the current invention, is a significant breakthrough.
Notwithstanding specific descriptions and details listed herein for the purposes of illustration, it must in no way be construed that these specific descriptions and details in any way limit or circumscribe the scope of the invention. Various specific ramifications of the current invention are anticipated.
It is anticipated that the combustion chamber may be made adjustable in diameter such that cooking pots of various sizes can be properly accommodated.
It is anticipated that various, alternate means may be employed for securing together the ends of the combustion chamber cylindrical wall and likewise the ends of the obturating band.
It is anticipated that the stove may be made larger.
It is anticipated that the stove may employ a windscreen or air jacket to enclose the combustion chamber, thereby providing additional protection from extremes of wind and weather.
It is anticipated that the combustion chamber may incorporate an array of dimples or ribs arranged to facilitate the centering of the cooking pot.
It is anticipated that various forms of shrouding or ducting may be employed to direct the flow of combustion air and facilitate the mixing of the combustion air and fuel vapor.
It is anticipated that the combustion chamber may employ divers means for effecting the metering and control of the combustion air flow.
It is anticipated that the stove may be made of more rigid and heavy material whereby it would be suitable for use when portability is not a primary concern.
It is anticipated that the pot supporting device may take a variety of alternate forms.
It is anticipated that the fuel vaporizer may employ divers means for effecting the vaporizing of the liquid fuel.
It is anticipated that provision might be made for supporting a larger cooking pot, frying pan, skillet, or similar cooking utensil on the stove.
Notwithstanding specific descriptions and details listed herein for the purposes of illustration, and notwithstanding various specific ramifications and embodiments listed above, it must in no way be construed that these specific descriptions, details, embodiments or ramifications in any way limit or circumscribe the scope of the invention.
Although preferred embodiments of the invention have been illustrated in the accompanying Drawings and described in the foregoing Detailed Description, it will be understood that the invention is not limited to the embodiments disclosed, but is capable of numerous rearrangements, modifications, and substitutions of parts and elements without departing from the spirit of the invention.
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A small, lightweight, portable cooking stove that utilizes alcohol as fuel and is suitable for backpacking, hunting, camping and similar activities. The cooking stove includes a combustion chamber which encloses, contains and regulates the entire combustion process. The stove also includes an efficient fuel vaporizer, which is adapted to perform in unison with the combustion chamber, to effect the metered and efficient mixing of the air and fuel vapor. An integral, simple and convenient means is provided to vary the intensity and pattern of the heat output, thereby controlling the cooking performance of the stove. The stove achieves high heat output and efficiency, low fuel consumption, and superior cooking performance in a small, lightweight, portable, convenient, simple and integrated assembly.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority under 35 U.S.C. § 119(e) to U. S. Provisional Application Serial No. 60/240,343, filed Oct. 13, 2000 (Attorney Docket No. 8296P).
FIELD OF THE INVENTION
[0002] This invention relates to a multi-layer dye-scavenging article for use in hand or machine washing systems. More particularly, this invention relates to a multi-layer article for introducing dye absorbing, dye transfer inhibiting and/or other detergent active materials into an aqueous washing system.
BACKGROUND OF THE INVENTION
[0003] In recent years there has been much interest in developing products which prevent the transfer of dyes between articles or garments when being laundered. When articles or garments, which have been colored using dyes of poor wash fastness are washed together with other articles or garments undesirable dye transfer may occur. As a result the articles or garments affected are many times rendered unsuitable for further use.
[0004] As a result of the aforementioned problem, many attempts have been made in the art to inhibit the transfer of dyes in the wash. One such solution involves delivery of dye transfer inhibitors and/or introduction of dye absorbers into the wash via a disposable substrate such as a non-woven sheet. However, one problem associated with currently available dye-scavenging articles arises from their single layer construction. When these single layer articles are placed in the wash, the dye absorbents and/or dye transfer inhibitors affixed to the substrate come into direct contact with the fabrics being laundered. Many consumers find this contact undesirable because of the perception that residue from the chemicals may remain on the articles or garments after laundering. Additionally, it is perceived by consumers that this contact may damage the articles or garments. Further, these single layer dye-scavenging articles known in the art lack the physical strength or structure to maintain their shape throughout the wash cycle. As a result, the articles tend to fold-up, minimizing the surface area available to the wash solution and greatly reducing the effectiveness of the articles.
[0005] Known dye-scavenging articles such as those disclosed in U.S. Pat. No. 5,881,412, require that the dye absorbent be chemically affixed to the surface of a substrate material, typically cellulosic materials, for example, cotton in any of its forms, purified cotton cellulose, cellulose sponge and the like. To affix the dye absorbent, the cotton substrate is modified by phosphorylation and chemisorption of the dye absorbent. The modification of the substrate and chemically bonding of the dye absorbents adds complexity and cost to the process and the ultimate article.
[0006] Accordingly the need remains for a dye-scavenging article that can be used to efficiently introduce dye-scavenging and/or dye transfer inhibiting compounds or other detergent active materials to the wash solution. There remains an additional need for a dye-scavenging article which provides a protective barrier between the active compounds contained therein and the articles or garments being washed, while still providing adequate contact between the active and the wash solution. Additionally, the article must be easily and efficiently manufactured and have sufficient physical strength or stiffness to prevent it from folding during the wash cycle.
SUMMARY OF THE INVENTION
[0007] The present invention meets the aforementioned needs by providing a multi-layer dye-scavenging article. When added to the wash solution, the dye-scavenging article prevents redeposition of fugitive dyes that may bleed from articles or garments in the solution. Multiple layers prevent contact between the articles or garments to be washed and the active compounds to be introduced into the wash solution. The physical strength or stiffness of the dye-scavenging article of the present invention prevents it from folding and thereby reducing its effectiveness.
[0008] In accordance with a first aspect of the invention a multi-layer dye-scavenging article is provided. The article comprises at least two layers oriented adjacently to each other and having one or more dye absorbing compounds fixed to at least one layer. The article can comprise any number of additional layers. The multi-layer dye-scavenging article comprises (a) a first layer and (b) a second layer. The first layer has first and second surfaces. The first layer preferably has a basis weight of from about 10 gram/square meter (gsm) to about 200 gsm, preferably from about 20 gsm to about 100 gsm, and most preferably from about 20 gsm to about 50 gsm. It is additionally preferred that the first layer have an opacity of less than 70%, preferably less than 50% and a water permeability of at least 0.06 ml/sec/cm 2 , preferably at least 0.1 ml/sec/cm 2 . If it is desired that the dye-scavenging article be compatible in machine drying appliances then it is further preferred that the first layer have a melting point of greater than or equal to 100° C., preferably greater than or equal to 130° C.
[0009] The second layer of the multi-layer dye-scavenging article also includes first and second surfaces. The second layer preferably has a basis weight of from about 30 gsm to about 200 gsm, preferably from about 60 gsm to about 150 gsm, and most preferably from about 80 gsm to about 120 gsm. It is additionally preferred, that the second layer have a water permeability of at least 0.06 ml/sec/cm 2 , more preferably at least 0.1 ml/sec/cm 2 . If it is desired that the dye-scavenging article be compatible in machine drying appliances then it is further preferred that the second layer have a melting point of greater than or equal to 100° C., more preferably greater than or equal to 130° C.
[0010] The multi-layer dye-scavenging article may optionally comprise (c) multiple additional layers. When present, the additional layers have first and second surfaces, a basis weight of from about 10 gsm to about 200 gsm, preferably from about 20 gsm to about 100 gsm, and most preferably from about 20 gsm to about 50 gsm. It is additionally preferred that the additional layers have an opacity of less than 70%, preferably less than 30% and a water permeability of at least 0.06 ml/sec/cm 2 , preferably at least 0.1 ml/sec/cm 2 . If it is desired that the dye-scavenging article be compatible in machine drying appliances then it is further preferred that the additional layers have a melting point of greater than or equal to 100° C., more preferably greater than or equal to 130° C.
[0011] The first layer is positioned adjacent to the second layer and any additional layers. In a preferred embodiment the second surface of the first layer is positioned adjacent to the first surface of the second layer. Additionally, the second surface of the second layer is positioned adjacent to the first surface of any optionally present additional layer. In another preferred embodiment of the present invention the first layer is coupled to the second layer and any additional layers. In another preferred embodiment the first, second and additional layers are non-woven materials.
[0012] It is therefore an object of the invention to provide a multi-layer dye-scavenging article which introduces dye absorbing and/or dye transfer inhibiting compounds to the wash solution. It is a further object of the present invention to provide a multi-layer dye-scavenging article that when added to the wash solution, prevents redeposition of fugitive dyes that may bleed from articles or garments in the solution. An additional object of the present invention is to provide a multi-layer dye-scavenging article that prevents contact between the articles or garments to be washed and the active compounds to be introduced into the wash solution. It is further an object of the present invention to provide a multi-layer dye-scavenging article with sufficient physical strength or stiffness to prevent it from folding and thereby reducing its effectiveness.
[0013] All percentages, ratios, and proportions herein are on a weight basis unless otherwise indicated. All documents cited are hereby incorporated by reference in their entirety.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] [0014]FIG. 1. is a cross sectional view of a multi-layer dye-scavenging article of the present invention.
[0015] [0015]FIG. 2. is a cross sectional view of an alternative embodiment of a multi-layer dye-scavenging article of the present invention.
[0016] [0016]FIG. 3. is a top view of a multi-layer dye-scavenging article of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0017] The present invention is directed to a multi-layer dye-scavenging article. More particularly, the present invention is directed to a multi-layer dye-scavenging article, which is capable of introducing dye absorbing, dye transfer inhibiting and/or other detergent active materials to the wash solution and additionally, providing a barrier between the actives fixed to at least one layer of the article and the articles and/or garments in the wash. Additionally, a dye-scavenging article of the present invention will have sufficient physical strength and/or structure to resist folding in the wash.
[0018] The present invention achieves the aforementioned benefits by providing a multi-layer dye-scavenging article. The article comprises a first layer, a second layer and optionally additional layers, oriented adjacent to each other, wherein a dye absorbing, dye transfer inhibiting compound and/or other detergent active material is fixed to at least one layer. In a preferred embodiment of the invention the article comprises a first layer, a second layer and a third layer, wherein a dye absorbing compound is fixed to both the first and second surfaces of the second layer, further wherein all the layers are coupled to each other such that the layers do not substantially separate during the wash cycle.
[0019] Turning now to FIG. 1, a multi-layer dye-scavenging article 11 comprises first layer 10 , second layer 12 , each layer having first and second surfaces, 14 , 16 , 18 and 20 respectively. As will be understood, layer thicknesses have been exaggerated and are not to scale to aid in clearly depicting all of the layers in the article. The multi-layer dye-scavenging article 11 comprises a first layer 10 having first and second surfaces 14 and 16 . First surface 14 is preferably directly exposed to the wash solution and the articles and/or garments being laundered. Second surface 16 preferably faces first surface 18 of second layer 12 . First layer 10 preferably has a basis weight of from about 10 gsm to about 200 gsm, more preferably from about 20 gsm to about 100 gsm, and most preferably from about 20 gsm to about 50 gsm. A basis weight of from about 10 gsm to about 200 gsm produces a layer with comfortable consumer aesthetics and adequate strength such that it maintains its structural integrity throughout the wash cycle. Additionally, having a basis weight from about 10 gsm to about 200 gsm, also provides satisfactory hand feel to the consumer.
[0020] It is additionally preferred that the first layer 10 have an opacity of less than about 70%, preferably less than about 50%. Where first layer 10 has an opacity of less than about 70% the consumer can see through first layer 10 to second layer 12 and view the dye absorbed from the wash solution on the second layer 12 of the article thereby providing a visual signal that fugitive dye is being absorbed.
[0021] It is further preferred that first layer 10 has a water permeability of at least 0.06 ml/sec/cm 2 to assure sufficient water is permitted to flow through first layer 10 and contact the dye absorbing and/or other detergent active material fixed to at least one other layer.
[0022] If it is desired that the dye-scavenging article be compatible for use in machine drying appliances then it is further preferred that first layer 10 have a melting point of greater than or equal to about 100° C., preferably greater than or equal to about 130° C.
[0023] The multi-layer dye-scavenging article 11 further comprises a second layer 12 . The second layer 12 has first and second surfaces 18 and 20 . The second layer 12 has a basis weight of from about 30 gsm to about 200 gsm, preferably from about 60 gsm to about 150 gsm, and most preferably from about 80 gsm to about 120 gsm. Second layer 12 also preferably has a water permeability of at least about 0.06 ml/sec/cm 2 , preferably 0.1 ml/sec/cm 2 . Additionally, if it is desired that the dye-scavenging article be compatible for use in machine drying appliances then it is further preferred that second layer 12 have a melting point of greater than or equal to 100° C., preferably greater than or equal to 130° C.
[0024] In a highly preferred embodiment of the present invention second layer 12 has a Taber stiffness rating of at least about 7 Taber Stiffness Units (TSU) preferably from about 10 TSU to about 200 TSU, and more preferably from about 10 TSU to about 100 TSU . When second layer 12 has the aforementioned stiffness rating, the resulting article has sufficient physical strength and rigidity such that it does not fold during the wash cycle, which can greatly reduce efficacy. The stiffness rating is preferably determined after any dye absorbing, dye transfer inhibiting or other detergent active material is fixed to the layer.
[0025] Dye adsorption and/or dye transfer inhibiting compounds are preferably fixed to second layer 12 , however one of skill in the art will recognize that these compounds may be fixed to any layer. While this may be accomplished via any method, a preferred method includes liquefying the compounds and coating the first and second surfaces, 18 and 20 of second layer 12 . Thereafter, the compounds are allowed to harden around the fibers of the second layer 12 . When the multi-layer dye-scavenging article 11 comprises only a first layer 10 and a second layer 12 , the dye absorbents or other detergent actives are preferably applied to the first surface 18 of the second layer 12 .
[0026] In an optional embodiment of the present invention, multi-layer dye-scavenging article 11 may further comprise any number of additional layers. An especially preferred embodiment of the present invention represented by FIG. 2 shows a multi-layer dye scavenging article 11 having a first layer 22 , a second layer 24 and a third layer 24 . The first layer 22 , has first and second surfaces 28 and 30 respectively. The second layer 24 has first and second surfaces 32 and 34 respectively. The third layer 26 has first and second surfaces 36 and 38 respectively. When additional layers are present the dye absorbents and/or other detergent active materials are preferably applied to both the first surface 32 and the second surface 34 of second layer 24 . Of course one of ordinary skill in the art will recognize that placement of dye absorbents and/or other detergent active materials on any layer is consistent with the present invention. A multi-layer dye-scavenging article with several layers may be provided, which have distributed between them several detergent actives. By providing an article with several layers one can deliver detergent active materials in the same product, which would otherwise be incompatible with each other by separating them by at least one layer. Suitable materials for all layers are described in detail below.
[0027] When present additional layers preferably have a basis weight of from about 10 gsm to about 200 gsm, more preferably from about 20 gsm to about 100 gsm, and most preferably from about 20 gsm to about 50 gsm. It is additionally preferred that additional layers have an opacity of less than about 70%, preferably less than about 50%. It is further preferred that additional layers have a water permeability of at least 0.06 ml/sec/cm 2 , more preferably at least about 0.1 ml/sec/cm 2. If it is desired that the dye-scavenging article be compatible for use in machine drying appliances then it is further preferred that additional layers have a melting point of greater than or equal to about 100° C., preferably greater than or equal to about 130° C.
[0028] Turning now to FIG. 3 a top view of a multi-layer dye-scavenging article according to the present invention is shown. The multi-layer dye-scavenging article 11 is shown with first surface 14 of first layer 10 illustrated. Individual means for coupling 40 are placed evenly or randomly throughout the article to couple one layer to the next layer. Optionally, there is a continuous means for coupling 42 along the perimeter of the article. The couplings prevent the layers from substantially separating from each other during the wash cycle and reducing efficacy of the actives. Coupling may be achieved by any means known in the art, including but not limited to pressure bonding, adhesive bonding, sonic bonding etc. One of ordinary skill in the art will recognize that the pattern or placement of the couplings is not critical as long as they adequately prevent separation of the layers. Accordingly, various patterns or designs and any combination thereof are contemplated by the present invention.
[0029] Basis weight, opacity, water permeability, melting point and stiffness values of anv material can be determined using the methods described below.
[0030] First and second layer, 10 and 12 and any additional layers of the present invention are preferably defined by several physical parameters including basis weight, opacity, water permeability, melting point and Taber stiffness rating.
[0031] Basis weight is calculated by cutting a sample of the material to be used for each respective layer and measuring its dimensions. The sample is then weighed. Basis weight is calculated by dividing the weight of the material by the square area of the material. A suitable measure of basis weight is grams per square meter (gsm). The basis weight of the material must be high enough to provide a substantial feel and thickness when handled by the consumer yet low enough such that the article moves with the articles and/or garments being washed.
[0032] Opacity is a relative percentage of how opaque, or transparent, a material is. This percentage may be determined using a Hunter Colorquest Spectrophotometer, commercially available from HunterLab. The opacity of all materials is measured when the materials are dry.
[0033] Water permeability is defined as the amount of water that passes through a material in a specified period of time. Sufficient water permeability can be accomplished either by using an entirely water pervious material, or alternatively by using a water impervious material supplied with holes, slits, apertures or other openings which allow water to flow from one side of the layer to the other. The water permeability of a particular material may be determined using the following method.
[0034] A 3.5in diameter Buchner funnel (diameter measured at base) is attached to a 2L vacuum flask. A vacuum source IS NOT attached to the flask side arm. A sample that has been cut into a 3.5in diameter circle is placed into the bottom of the funnel. The sample is gently wetted with a small amount of water to prevent “floating” the sample. Add 100 mL of filtered deionized water to the funnel; starting a timer when the water is added. Stop the timer after all the water has drained from the funnel (evident by a lack of “puddles” formed in the funnel), and record the total number of seconds it took to drain completely. To get the permeability value, the # of seconds for the test is divided by 100, which results in mL/sec. Divide the result by 62.07, which is the surface area of the test sample in squate centimeters. Water Permeability is expressed as mL/sec./cm 2 .
[0035] It is preferred that layers directly adjacent to dye absorber or other detergent active have a water permeability of at least about 0.06 ml/sec/cm 2 , preferably 0.1 ml/sec/cm 2, to allow a high volume of water to penetrate the article such that the actives within the article are effective. It is additionally preferred that all article layers have water permeabilities of at least about 0.06 ml/sec/cm 2 , preferably 0.1 ml/sec/cm 2 . However, one of ordinary skill in the art will recognize the possibility that the article contain some layers that are completely impermeable for the purpose of separating incompatible detergent active materials. In such a case the article would comprise a combination of water permeable and impermeable layers. This is within the scope of the present invention so long as sufficient release of detergent active material is permitted. By sufficient release is meant that portion of detergent active material necessary to achieve the desired benefit. It will be recognized by one of skill in the art that the amount of detergent active material necessary to be released into the wash solution will vary depending on the active and the desired benefit.
[0036] Melting point is the temperature at which the material begins the transition from solid state to liquid state. This can be determined by using ASTM method #E 324-94. All layers of the multi-layer article of the present invention preferably have a melting point of greater than or equal to 100° C. This melting point is necessary to ensure that the article retains its integrity through the wash and most importantly does not melt in the heat of a standard, commercially available home laundry dryer.
[0037] Taber stiffness rating is a measure of a materials stiffness and resiliency. This rating can be determined using a Taber Stiffness Tester Model #150-E, available commercially from Taber Industries.
[0038] The layers used in the articles of the present invention may preferably have a thickness varying from about 5 to about 500 mils, preferably from about 5 to about 250, and most preferably from about 5 to about 200. Examples of suitable materials which may be employed, include, among others, foam, foil, film, sponge, paper, woven cloth, and nonwoven cloth. Preferred articles are made from a flexible material, and include those made from paper, woven cloth, nonwoven cloth and flexible films. The term “cloth”, as used herein, means a woven or nonwoven fabric or cloth used as an article., in order to distinguish it from the term “fabric” which is used to mean the textile fabric to be laundered. Preferred article materials should exhibit only a minimal amount of Tinting when used in automatic washers and dryers. Preferably, the materials employed in the articles of the present invention are wet-strength paper or nonwoven cloth materials.
[0039] Paper materials which can be employed herein encompass the broad spectrum of known paper structures and are not limited to any specific papermaking fiber or wood pulp. Thus, the fibers derived from soft woods, hard woods, or annual plants, such as bagasse, cereal straw, and the like, and wood pulps, such as bleached or unbleached kraft, sulfite, soda ground wood, or mixtures thereof, can be used. Moreover, the paper article materials, which may be employed in the articles of the present invention are not limited to specific types of paper, so long as the paper exhibits the required physical characteristics as defined above.
[0040] A specific example of a type of paper article material preferred herein is a two-ply paper having a basis weight of about 50 pounds per 2,880 sq. ft. made from, for example, a mixture of ground wood and kraft bleached wood pulps. Another example is the absorbent, multi-ply toweling paper which is disclosed in U.S. Pat. No. 3,414,459, Wells, issued Dec. 3, 1968, said patent being incorporated herein by reference.
[0041] The preferred nonwoven cloth materials which may be used in the invention herein are generally defined as adhesively bonded fibrous products, having a web or corded fiber structure (where the fiber strength is suitable to allow carding) or comprising fibrous mats, in which the fibers are distributed haphazardly or in a random array (that is, an array of fibers in a carded web wherein partial orientation of the fibers is frequently present as well as a completely haphazard distributional orientation) or substantially aligned. The fibers can be natural, such as wool, silk, jute, hemp, cotton, linen, sisal, or ramie; or synthetic, such as rayon, cellulose ester, polyvinyl derivatives, polyolefins, polyamides, or polyesters. Any diameter or denier of fiber, generally up to about 10 denier, are useful in the present invention.
[0042] Methods of making nonwoven cloths suitable for use herein are not a part of this invention and, being well known in the art, are not described in detail in this application. Generally, such cloths are made by dry- or water-laying processes in which the fibers are first cut to desired lengths from long strands, conveyed via air or water, and then deposited onto a screen through which the fiber-laden air or water is passed. The deposited fibers are then adhesively bonded together, dried, cured, and otherwise treated as desired to form the nonwoven cloth. Nonwoven cloths made of polyesters, polyamides, vinyl resins, and other thermoplastic fibers can be spun bonded. In this process the fibers are spun out onto a flat surface and bonded (melted) together by heat or by a chemical reaction.
[0043] When the article described herein is a nonwoven cloth made from fibers deposited haphazardly or in a random array on a screen, the articles exhibit excellent strength in all directions and are not prone to tear or separate when used successively in an automatic washer and dryer.
[0044] Preferably, the nonwoven cloth is water-laid or dry-laid and is made from cellulosic fibers, particularly from regenerated cellulose or rayon, which have been lubricated with a standard textile lubricant. It is preferred that the fibers are from about 3/16 inch to about 2 inches in length, and are from about 1.5 to about 5 denier. It is also preferred that the fibers are at least partially oriented haphazardly, particularly substantially haphazardly, and are adhesively bonded together with a hydrophobic or substantially hydrophobic binder resin, particularly with a non-ionic self-crosslinking acrylic polymer or a mixture of such polymers. A preferred cloth comprises by weight about 85% fiber and about 15% binder resin polymer, and has a basis weight of from about 50 to about 90 grams per square yard.
[0045] If the articles are formulated so as to be used in the automatic dryer, subsequent to their use in the automatic washer, the materials used may be formed such that they have slit or aperture openings in order to improve their functioning in the dryer. These openings may also improve the release of the surface-active composition in the automatic washer. However, in order to be used in the articles of the present invention, it is desirable that the article materials meet the air permeability criteria set forth herein in the absence of the slits. Such openings are described in U.S. Pat. No. 3,944,694, McQueary, issued Mar. 16, 1976; U.S. Pat. No. 3.956.556, McQueary, issued May 11, 1976; U.S. Pat. No. 4,007,300, McQueary, issued Feb. 8, 1977, and U.S. Pat. No. 4,012.540, McQueary, issued Mar. 15, 1977, all of which are incorporated herein by reference.
[0046] The articles usable herein can be “dense”, or they can be open and have a high amount of “free space”, as long as they satisfy the previously defined physical criteria. Free space, also called “void volume”, is that space within an article structure which is unoccupied. For example, certain absorbent, multi-ply paper structures comprise plies embossed with proturberances, the ends of which are mated and joined. This type of paper structure has free space between the unembossed portions of the plies, as well as between the fibers of the paper plies themselves. A nonwoven cloth also has such space between its fibers. The free space of the article can be varied by modifying the density of the fibers of the article. Thus, articles with a high amount of free space generally have low fiber density, and articles having a high fiber density generally have a low amount of free space. The amount of free space, that a material has is not critical to its use as an article herein, although it may have a direct effect on the water permeability of the article material. Additionally, the amount of free space in the article structure may affect the amount of the active components, which must be applied to the article in order to achieve a desired coating effect.
[0047] In a preferred embodiment, the layers are superimposed upon each other. For the purposes of illustration only and not to limit the invention only the first two layers will be discussed in this section. However, the means of superimposition and coupling are to be understood to apply to all layers in the article. The first layer 10 is preferably superimposed on the second layer 12 and any additional layers. To insure proper fluid transfer between the first layer 10 and the second layer 12 it is preferred that the first layer 10 be substantially coupled to the underlying second layer 12 . (As used herein, the term “coupled” encompasses configurations whereby a layer is directly secured to another layer by coupling one layer to the other layer, as well as configurations whereby a layer is indirectly secured to another layer by coupling the layer to an intermediate member or members which in turn are coupled to the other layer.) By coupling the first layer 10 to the second layer 12 the first layer 10 will have a reduced tendency to separate from the second layer during the course of a wash/dry cycle. Separation of the second layer 12 from the first layer 10 may inhibit or reduce the efficiency of dye absorption from the wash solution. The first layer may be coupled to the second layer by any suitable means, including, but not limited to the use of adhesives such as by spray-gluing or applying lines or spots of adhesives between the first layer 10 and the second layer 12 . Alternatively, or additionally, the first layer 10 may be coupled with the second layer 12 simply by wrapping the first layer 10 about the second layer 12 , by entangling the fibers of the second layer 12 with the first layer 10 , by fusing the first layer 10 to the second layer 12 with a plurality of discrete individual fusion bonds, or by any other means known in the art including but not limited to adhesives, heat, pressure, heat and pressure, extrusion, and ultrasonic bonds.
[0048] A suitable first layer 10 may be manufactured from a wide range of materials such as woven and nonwoven materials; polymeric materials such as apertured formed thermoplastic films, apertured plastic films, and hydroformed thermoplastic films; porous foams; reticulated foams; reticulated thermoplastic films; and thermoplastic scrims. Suitable woven and nonwoven materials can be comprised at least partially of natural fibers (e.g., wood or cotton fibers), synthetic fibers (e.g., polymeric fibers such as polyester, polypropylene, or polyethylene fibers) or from a combination of natural and synthetic fibers.
[0049] Preferred materials for use in the first layer 10 are selected from high loft nonwoven materials and apertured formed film materials. Apertured formed films are especially preferred for the first layer 10 because they are pervious to water. Suitable formed films are described in U.S. Pat. No. 3,929,135, entitled “Absorptive Structures Having Tapered Capillaries”, which issued to Thompson on Dec. 30, 1975; U.S. Pat. No. 4,324,246 entitled “Disposable Absorbent Article Having A Stain Resistant Topsheet”, which issued to Mullane, et al. on Apr. 13, 1982; U.S. Pat. No. 4,342,314 entitled “Resilient Plastic Web Exhibiting Fiber-Like Properties”, which issued to Radel, et al. on Aug. 3, 1982; U.S. Pat. No. 4,463,045 entitled “Macroscopically Expanded Three-Dimensional Plastic Web Exhibiting Non-Glossy Visible Surface and Cloth-Like Tactile Impression”, which issued to Ahr et al. on Jul. 31, 1984; U.S. Pat. No. 4,780,352 entitled “Covering Structure For Absorbent Hygienic Sanitary Products, and an Absorbent Product Having Such A Covering”, which issued to Palumbo on Oct. 25, 1988; U.S. Pat. No. 5,006,394 “Multilayer Polymeric Film” issued to Baird on Apr. 9, 1991.
[0050] It is possible that any layer be made of a hydrophobic material. While not necessary it may be desirable to treat the surface of any hydrophobic layer to increase its hydrophillic nature, such that liquids will transfer through that layer more rapidly. This diminishes the likelihood that the wash solution will flow around the layer rather than being drawn through the layer and into contact with the next layer or the detergent active. A layer can be rendered hydrophilic by treating it with a surfactant. Suitable methods for treating the layer with a surfactant include spraying the layer with the surfactant or immersing it in the surfactant. Suitable methods of treating a layer with a surfactant are described in U.S. Pat. No. 4,950,254 issued to Osborn and in U.S. Pat. No. 5,520,875.
[0051] Any of several known manufacturing techniques may be used to manufacture each layer. 8296
[0052] In another embodiment, the first layer is an apertured formed film which comprises microscopic surface aberrations on the land areas of the formed film. The film also includes microscopic depositions of a low surface energy material at least some of which depositions are located on the land areas between the microscopic surface aberrations. Such a preferred apertured formed film is more fully described in allowed U.S. patent application Ser. No. 08/826,508 entitled “Fluid Transport Webs Exhibiting Surface Energy Gradients” filed in the name of Ouellette, et al. on Apr. 11, 1997 (PCT Publication WO 96/00548, published Jan. 11, 1996).
[0053] The layers may also be comprised of a web material. The term “web”, as used herein, refers to a sheet-like material comprising a single layer of material or a laminate of two or more layers. The web may be comprised of a structural elastic-like film (SELF) web material in a stretched or elongated condition. Examples of SELF webs are disclosed in International Application WO 95/03765, entitled “Web Materials Exhibiting Elastic-Like Behavior”, published Feb. 9, 1995 in the name of Chappell et al. which is incorporated herein by reference. The web materials can be constructed of a single layer of material or alternatively, may be constructed of two or more layers.
[0054] Suitable web materials for a layer may be comprised of polyolefins such as polyethylenes, including linear low density polyethylene (LLDPE), low density polyethylene (LDPE), ultra low density polyethylene (ULDPE), high density polyethylene (HDPE), or polypropylene and blends thereof with the above and other materials. Examples of other suitable polymeric materials which may also be used include, but are not limited to, polyester, polyurethanes, compostable or biodegradable polymers, heat shrink polymers, thermoplastic elastomers, metallocene catalyst-based polymers (e.g., INSITE® available from Dow Chemical Company and EXXACT® available from Exxon), and breathable polymers. The web materials may also be comprised of a synthetic woven, synthetic knit, nonwoven, apertured film, macroscopically expanded three-dimensional formed film, absorbent or fibrous absorbent material, foam filled composition or laminates and/or combinations thereof. The nonwovens may be made but not limited to any of the following methods: spunlace, spunbond, meltblown, carded and/or air-through or calender bonded, with a spunlace material with loosely bonded fibers being the preferred embodiment.
[0055] The web materials may be made from two-dimensional apertured films and macroscopically expanded, three-dimensional, apertured formed films. Examples of macroscopically expanded, three-dimensional, apertured formed films are described in U.S. Pat. No. 3,929,135 issued to Thompson on Dec. 30, 1975; U.S. Pat. No. 4,324,246 issued to Mullane, et al. on Apr. 13, 1982; U.S. Pat. No. 4,342,314 issued to Radel, et al. on Aug. 3, 1982; U.S. Pat. No. 4,463,045 issued to Ahr, et al. on Jul. 31, 1984; and U.S. Pat. No. 5,006,394 issued to Baird on Apr. 9, 1991. Each of these patents are incorporated herein by reference.
[0056] The web materials may comprise laminates of apertured films and nonwoven materials whereby in the process of forming such materials, the connections between a plurality of the nonwoven fibers are broken up to protrude slightly through the apertures of the apertured film.
[0057] It may be desirable in certain embodiments to have the composite web exhibit a certain degree of bulkiness and bending resistance. Laminates of polymer films with high-loft nonwoven materials, and laminates with multi-layers of nonwovens are ways of providing increased bulk. Other methods for creating bulk include the formation of a single layer of polymer film in the manner of this invention followed by prestretching of the film and subsequent application of the nonwoven to one or both sides while the polymer film is in its prestretched condition. Upon relaxation of the stretch, the nonwoven material forms puckers which give the material added bulk. Another method for making bulky laminates is by forming individual polymeric film layers in the manner of this invention, followed by lamination of multiple layers of these materials. Three dimensionally apertured films that have been formed using the method described herein also provide good bulk in a laminate structure.
[0058] Cellulosic nonwovens, particularly nonwovens wherein the fibrous material consists essentially of cellulosic products, are economically and environmentally preferred. Cellulosic nonwovens that are especially suitable for use in the present invention are described in U.S. Pat. No. 3,905,863 issued to Ayers on Sep. 16, 1975; U.S. Pat. No. 3,974,025 issued to Ayers on Aug. 10, 1976; and U.S. Pat. No. 4,191,609 issued to Trokhan on Mar. 4, 1980. Each of these references are incorporated herein by reference in their entirety.
[0059] Each layer of the multi-layer article may be formed from similar or different materials. The nonwoven may be treated, for example, to join the fibers of the nonwoven or to enhance the strength of the nonwoven. Such treatment may involve hydroentanglement, thermal bonding, or treatment with a binder.
[0060] Examples of preferred materials are tissue paper having a basis weight of about 40 gsm made with northern softwood Kraft pulp, or Hydraspun™ from Dexter Corporation, a hydroentangled wet laid nonwoven having a basis weight of 60 gsm, or Visorb™ commercially available from Buckeye Technologies, which is an air laid non-woven comprised of 72% wood pulp, 25% bicomponent fibers and 3% latex and has a basis weight of 100 gsm.
[0061] Each layer of the material may be a discrete composition which may or may not be the same or similar to any other layer of the article. Any number of additional layers may be used.
[0062] In an alternative embodiment of the present invention the multiple layers of the dye-scavenging article described herein are produced in succession on a single web. As described above, the layers of the article can be produced independently of one another and afterward combined via any known adhesive means to form a multi-layer article. However, it is possible and in some cases desirable to produce a multi-layer article wherein all or some of the layers are produced in the form of a single web. For instance with a standard non-woven machine it is possible to lay down each different layer in succession on a single air-laid line such that the web leaving the line, while being a single roll of material, is comprised of multiple layers each having distinct physical characteristics.
[0063] It is preferred that the dye absorber is a substantially insoluble cross-linked polymeric amine, selected from existing polymers, polymeric amines formed by copolymerization, polymeric amines formed by cross-linking soluble polyamines, or polymeric amines formed by reacting cationic condensates of amines with cross-linking agents. In a preferred embodiment the dye absorber can be grafted onto the dye scavenging article by any suitable grafting technique, including but not limited to chemical, thermal, and ultraviolet grafting techniques. Specific dye absorbing compounds and methods for making are described in co-pending U.S. patent application Ser. No.______ titled Laundering Aid for Preventing Dye Transfer, filed Oct. 13, 2000, incorporated herein in its entirety.
[0064] The following examples are presented to further illustrate, but not to limit, the present invention:
EXAMPLE 1
[0065] A mixture of the following composition is prepared:
% by weight Polyvinyl pyrrolidone co-vinyl imidazole 1 15.0 PAE resin 2 3.75 Polyvinylpyridine N oxide 2.5 tripropylolpropane triglycidylether 1.0 Water/Inerts to 100%
[0066] The solution is padded on a Visorb X622 (basis weight 100gsm, ex Buckeye Technologies, Memphis Tenn.) using a Werner Mathis 2 roll Padding Machine Model HVF. The nip pressure was set so as to achieve a pickup of about 190%. The padded substrate is dried and cured in a convection oven at 250° F. for 20 minutes
EXAMPLE 2
[0067] A three layer dye-scavenging article was prepared as follows:
[0068] Layer 1: 18gsm Softex 50% polypropylene/50% polyethylene from BBA Nonwovens,
[0069] Layer 2: 100 gsm Visorb X622 with crosslinked polymer from example 1
[0070] Layer 3: 18gsm Softex Softex 50% polypropylene/50% polyethylene from BBA Nonwovens
[0071] The three layers are coupled such that layer 2 forms the core and layers 1 and 3 form each of the outer layers. The perimeter of the article is thermally sealed. The layers are also bonded together by sonic bonding. The physical properties of the three layers are shown below
Taber Water Permeability Stiffness % Opacity (mL/sec/cm 2) Rating Layers 1 & 3 29 0.20 Not applicable Ply 2 Not 0.23 26.7 applicable
EXAMPLE 3
[0072] A mixture of the following composition is prepared:
% by weight Polyvinyl pyrrolidone co-vinyl imidazole 1 15.0 PAE resin 2 3.75 Polyvinylpyridine N oxide 2.5 tripropylolpropane triglycidylether 1.0 Water/Inerts to 100%
[0073] The solution is padded on a Bounty Rinse and Reuse™ Tissue paper (basis weight 21gsm, ex Procter and Gamble, Cincinnati, Ohio) using a Werner Mathis 2 roll Padding Machine Model HVF. The nip pressure was set so as to achieve a pickup of about 120%. The padded substrate is dried and cured in a convection oven at 250° F. for 20 minutes.
EXAMPLE 4:
[0074] A five layer dye-scavenging article is prepared as follows:
[0075] Layer 1: 18gsm Softex 50% polypropylene/50% polyethylene from BBA Nonwovens,
[0076] Layers 2,3 and 4: 21gsm polymer coated Bounty Rinse and Reuse™ Tissue paper from example 3
[0077] Layer 5: 18gsm Softex 50% polypropylene/50% polyethylene from BBA Nonwovens
[0078] Layers 2-4 are coupled together such that they form the core and layers 1 and 5 form each of the outer layers. The perimeter is glued using a hot melt water resistant glue. The layers are also point bonded together with the glue. The physical properties of the layers are shown below
Water Permeability Taber Stiffness % Opacity (mL/sec/cm 2 ) Rating Layers 29 0.20 Not applicable 1 and 5 Layers 2-4 Not 0.23 11.5 applicable
EXAMPLES 5-18
[0079] Examples 5-18 exemplify non-wovens suitable for use as the first layer and/or any optional additional layers of the multi-layer dye scavenging article.
[0080] A multi-layer dye scavenging article is produced as shown in example 1 with the following webs
Layer 1 Layer 2 Layer 3 Example Apertured hexagonal layer from Apertured hexagonal 5 film, dot embossed example 1 film, dot embossed Code ER41 ex. PGI Code ER41 ex. PGI Example Spunlace, 70% Rayon/ layer from Spunlace, 70% Rayon/ 6 30% polyester, code example 1 30% polyester, code 5763 ex. PGI 5763 ex. PGI Example SMS ex. PGI Inc. layer from SMS ex. PGI 7 example 1 Example Softex, 40gsm ex. BBA layer from Softex, 40gsm ex. 8 Nonwovens example 1 BBA Nonwovens Example 1.0 mil Apertured film layer from 1.0 mil Apertured film 9 code X-26909 ex. example 1 code X-26909 ex. Tredegar Tredegar Example Three layered apertured layer from Three layered 10 web example 1 apertured web polypopylene/Tissue/ polypopylene/Tissue/ pro pro Example Through-Air Bond 60% layer from Through-Air Bond 11 pulp/ 40% Dankalon example 1 60% pulp/ 40% code 4093 ex. PGI Dankalon code 4093 ex. PGI Example Thermal Bond T-Bond layer from Thermal Bond T-Bond 12 Cuff code 67700 ex. example 1 Cuff code 67700 ex. PGI PGI Example Apertured hexagonal layer from Absent 13 film, dot embossed example 1 Code ER41 ex. PGI Example 1.0 mil Apertured film layer from Absent 14 code X-26909 ex. example 1 Tredegar Compar- ative Examples Example Spunlace 55% Pulp/ layer from Spunlace 55% Pulp/ 15 45% Polyester code example 1 45% Polyester code 5529 ex. PGI 5529 ex. PGI Example Thermal Bond layer from Thermal Bond 16 Polypropylene/rayon example 1 Polypropylene/rayon code 149189 ex. BBA code 149189 ex. BBA Nonwovwns Nonwovens Example Polyethylene film 1.0 layer from Polyethylene film 1.0 17 mil example 1 mil Example Saran Wrap layer from Saran Wrap 18 example 1
[0081] The physical properties of layers 1 and 2 are shown in the table below
Water % Permeability Opacity (mL/sec/cm 2 ) Example 5 45.5 0.40 Example 6 59.7 0.25 Example 7 36.8 0.05 Example 8 42.7 0.20 Example 9 7.7 0.09 Example 10 60.5 0.32 Example 11 33.9 0.32 Example 12 34.7 0.14 Example 13 45.5 0.40 Example 14 7.7 0.09 Example 15 71.9 0.07 Example 16 71.7 0.18 Example 17 0.2 <0.01 Example 18 1.5 <0.01
EXAMPLES 19-28
[0082] Examples 19-28 exemplify materials suitable for use as layer 2.
Layer 1 Layer 2 Layer 3 Example 19 18gsm Softex 50% Visorb 110gsm 25% 18gsm Softex 50% polypropylene/50% bicomponent fiber, 72% polypropylene/50% polyethylene from pulp, 3% latex ex.Buckeye polyethylene from BBA BBA Nonwovens Technologies, Memphis, Nonwovens TN treated with crosslinked polymer as shown in Example 1 Example 20 18gsm Softex 50% Visorb 155 gsm 25% 18gsm Softex 50% polypropylene/50% bicomponent fiber, 72% polypropylene/50% polyethylene from pulp, 3% latex ex.Buckeye polyethylene from BBA BBA Nonwovens Technologies, Memphis, Nonwovens TN Example 21 18gsm Softex 50% Airlaid 80% pulp, 20% 18gsm Softex 50% polypropylene/50% bonding fiber product code polypropylene/50% polyethylene from GH.100.1006 ex Concert, polyethylene from BBA BBA Nonwovens Germany Nonwovens Example 22 18gsm Softex 50% Wetlaid 60% pulp/40% 18gsm Softex 50% polypropylene/50% polyester code 7925 PGI polypropylene/50% polyethylene from Chicopee treated with polyethylene from BBA BBA Nonwovens crosslinked polymer as Nonwovens shown in Example 1 Example 23 18gsm Softex 50% Wetlaid 40% pulp/60% 18gsm Softex 50% polypropylene/50% polyester code 7945 PGI polypropylene/50% polyethylene from Chicopee treated with polyethylene from BBA BBA Nonwovens crosslinked polymer as Nonwovens shown in Example 1 Example 24 18gsm Softex 50% Tissue paper (basis weight 18gsm Softex 50% polypropylene/50% 60 gsm ex. Procter and polypropylene/50% polyethylene from Gamble, Cincinnati, OH) polyethylene from BBA BBA Nonwovens treated with polymer as Nonwovens shown in example 3 Example 25 18gsm Softex 50% Hydroentangled web (50 18gsm Softex 50% polypropylene/50% gsm) sold under the trade polypropylene/50% polyethylene from name Hydraspun ex. polyethylene from BBA BBA Nonwovens Dexter Corp. Windsor Nonwovens Locks, CT treated with polymer as shown in Example 3 Comparative examples Example 26 None Glowhite Color catcher none supplied by Acdo, Bolton, England Example 27 Visorb l03g/sq m. 16% bicomponent fiber, 81% pulp, 3% latex ex.Buckeye Technologies, Memphis, TN Example 28 2 layers of Tissue paper, each of basis weight 19 g/sqm sold under the Trade name Bounty Rinse and reuse™ ex. Procter and Gamble, Cincinnati, OH)
[0083] [0083] Water Permeability Taber Stiffness (mL/sec/cm 2 ) Rating Example 19 0.2 26.4 Example 20 0.3 13.3 Example 21 0.2 7.8 Example 22 0.06 22.5 Example 23 0.05 21.3 Example 24 0.2 25.6 Example 25 0.3 8.2 Example 26 0.2 6.1 Example 27 0.3 3.7 Example 28 0.2 2.1
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A multi-layer dye-scavenging article for use in hand or machine washing systems is disclosed. More specifically, a multi-layer article for the introduction of dye absorbing, dye transfer inhibiting and/or other detergent active materials into an aqueous wash system is disclosed.
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This is a continuation of copending application Ser. No. 536,799, filed on Sept. 28, 1983 now abandoned.
BACKGROUND OF THE INVENTION
The present invention pertains to ice handling systems and more particularly to systems where the removal of dangers presented by icebergs to marine platforms or marine vessels located on the open seas.
Presently, icebergs present a constant danger to not only vessels on high seas but also offshore oil rigs or platforms located as far as several hundred miles from the coast.
Icebergs come from glaciers which end at the seashore. A glacier is a moving mass of ice that travels across the land and terminates at the ocean. As the glacier moves to the ocean, portions break off and are termed icebergs. Icebergs are primarily fresh water ice since they are composed of packed ice and snow which has been compressed over hundreds of years. The compression of snow over a large period of time results in a cohesive structure which has small bubbles or pockets of air trapped within.
Icebergs are irregular in shape, each being unique. As an iceberg travels through the ocean, it is constantly melting, at various rates dependent on the temperature of the air and water surrounding the iceberg. As such, the center of gravity will slowly change and the iceberg may roll in the water, presenting further dangers to personnel and equipment working near the iceberg.
Although icebergs are commonly encountered in the North Atlantic from the glaciers in Greenland and Canada, icebergs in smaller quantities are encountered in the Pacific from the Alaskan glaciers. Additionally, large masses of ice are encountered in the Southern Hemisphere from the Coast of Antarctica. These ice masses are similar to the icebergs located in the Northern Hemisphere, although they have a larger surface area and lower height above the water line. Many icebergs will melt at sea and never present a problem, however, many travel towards the equator along the coast line of one of the continents. These icebergs cause dangers to ships when they travel in a shipping lane or to offshore platforms, such as oil rigs, when they travel along the coast.
The danger posed to offshore platforms was not a major concern when the world oil supply was plentiful on land. However, since oil production has moved offshore, particularly in places such as the North Sea or the Hybernia Oil Field off the Coast of Newfoundland, the danger of icebergs has become a significant problem in oil production. An iceberg may weigh as much as a hundred million tons and have a water speed of one half knot. The force with which an iceberg may collide with a platform is devastating.
Under normal conditions, an iceberg watch is kept to monitor iceberg movement. Icebergs which are within one hundred miles of a platform are checked daily to determine whether they pose a danger to a production platform. If the iceberg approaches the platform, a tow line is placed around the iceberg and an attempt is made to maneuver the iceberg to avoid collision wiht the platform. If the threat of collision cannot be safely avoided, a floating platform may be disconnected from the subsea wellheads and moved out of the path of the iceberg. The disconnection of a production platform may require a loss of a weeks production time. Since the disconnection may require as much as 48 hours, a wide safety margin must be left to assure the prevention of a collision.
The disconnection of a production platform does not remove all detrimental effects of icebergs since flowlines are connected between an onshore storage area and the offshore production platform. Icebergs, because of the specific gravity, float with their majority of their mass beneath the surface of the water. As such, their draft or depth below the water line, may be several hundred feet. Flowlines may be in only several hundred feet of water and can be damaged or severed by icebergs dragging bottom.
To reduce the draft of an iceberg, many methods have been attempted, such as blasting the iceberg apart. This method has proven unsatisfactory due to the nature of an iceberg. An iceberg is similar to a very densely packed snowball with a great amount of air trapped and compressed within as small air bubbles or pockets of air. The force of an explosive charge is absorbed by the generally deformable structure of the ice.
The method of moving icebergs by placing a tow rope around the peripheral at water level has several disadvantages. First, an iceberg is extremely unstable as it floats in the water and may roll or tip over when towing proceeds. Second, an iceberg generally decreases in size with respect to height out of the water and the tow rope may slide up and over the top of the iceberg.
Other ice masses have similar difficulties in movement by tow ropes circling the ice mass. First, the overall size of the surface area may render the length of the tow line prohibitive. Second, an ice mass having a flat surface and a low height above water may not allow the tow rope to securely rest around the ice mass.
Monitoring icebergs by aircraft iceberg watch has several deficiencies. Aircraft watch or marine vessel watch is weather related. Inclement weather or fog may inhibit aircraft availability. Either inclement weather or fog renders iceberg watch by marine vessel extremely dangerous. As a result, an iceberg may travel for several days while monitoring is impossible. If the iceberg has approached an offshore platform during the inclement weather, conditions may render the detachment and movement of the platform extremely dangerous if not impossible.
SUMMARY OF THE INVENTION
A method for moving an ice mass is disclosed wherein an anchor for receiving a tow line is attached to an iceberg near its center of gravity and towed to a location away from equipment and machinery which may be damaged by the iceberg. The high pressure fluid drill is mounted at the end of a tubular shaft. The drillhead is advanced into the iceberg at a point below the water line to the approximate center of gravity until the shaft is in the iceberg.
The drilling operation is terminated and compressed carbondioxide or similar fluid is circulated through the tubular shaft to quick freeze the shaft within the iceberg. The shaft is configured at the end opposite the drillhead to retain one end of the tow line. Upon completion of the freezing process, the iceberg may be moved by way of tow line to a location remote from equipment endangered by the iceberg.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partially sectionalized plan view of an ice drill.
FIG. 2 is a front view of a deployment apparatus.
FIG. 3 is a side view of FIG. 2.
FIG. 4A through 4C are plan views of the deployment of an ice anchoring device.
FIGS. 5A through 5C are plan views of an ice identification system.
FIG. 6 is a plan view of an ice fracturing device.
FIG. 7 is a plan view of an iceberg.
FIG. 8A through 8C are plan views of the operation of the device of FIG. 6.
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides solutions to many ice related problems which create hazzards to not only equipment but also to human life. The use of the present invention removes the requirement of personnel in dangerous situations.
Referring now to FIG. 1, a side sectional view of an ice drill 12 is illustrated in iceberg 13 as having an external housing 14 and an internal concentric housing 16 connected at a deployment end 18 and a drill head end 20 by connectors 22. A rotatably mounted drill head 24 is mounted at drill head end 20 having water lines 26 providing fluid flow to drill head 24 and hydraulic fluid lines 28 to a hydraulic motor 30. The overall length of ice drill 12 is preferably fifteen feet, however, a longer or shorter length may be used with satisfactory results. External housing 14 is preferably steel, chosen for its rigidness and ability to conduct heat. However, any rigid conduit may be used and ability to conduct heat is not required if drill 12 is to be removed when a hole is complete. Under certain conditions ice drill 12 is to be left in the ice mass, drill and the ability of housing 14 to conduct heat is preferred. As such, a metallic conductive material is preferred in the construction of housing 14.
As illustrated in FIG. 1, a fluid refrigerant hose 32 may be added with expansion nozzles 34 connected between hose 32 and an expansion area 36 defined by external housing 14 and internal housing 16. This addition may be used to freeze the drill in place to provide a solid anchor to the ice mass being drilled. Threading 37 may be machined onto external housing 14 to provide greater freezing area. A clevis 38 is provided at deployment end 18 of external housing 14. A tow line (not shown) or the like may be attached to clevis 38.
Drill head 24 has water passages (not shown) angularly drilled therein to provide water streams at angles with face 40 of drill head 24 as indicated by arrows A and B. In operation, high pressure water, or similar liquid, is provided to the passages in drill head 24 through water line 26. The high pressure water has an eroding effect on iceberg 13. Hydraulic motor 30 rotates drill head 24. As hydraulic motor 30 is driven by fluid pressure from fluid line 28, exhaust from hydraulic motor 30 exits through annular opening 40 defined by the space between end 20 of housing 14 and drill head 24. As drill head 24 rotates water streams A and B travel in a circular path, eroding a borehole 42 in iceberg 13 without grinding or producing tailings to block the efficiency or progress of drill head 24.
In operation ice drill 12 is placed in position at the edge of the ice along the axis of a desired borehole. Pressurized fluid is fed to drill head 24 through water line 26 to provide eroding water streams A and B. A fluid flow is fed to hydraulic motor 30 through fluid line 28 to rotate drill head 24. As water streams A and B rotate with the movement of drill head 24, ice is melted in a generally arcuate area. Melted ice as well as overflow from streams A and B are exhausted with hydraulic fluid from hydraulic motor 30 along the space between outer housing 14 and a borehole 42 provided thereby. Forward motion, that is motion into the iceberg, is exerted on deployment end 18 of external housing 14. This forward motion forces exhaust fluids and melted or eroded ice out of borehole 42.
Whenever ice drill 12 is to be left in iceberg 13 or some other ice mass, inner concentric housing 16 is used to provide expansion area 36.
A compressed fluid such as carbon dioxide may be fed to expansion area 36 through hose 32 to nozzle 34. The compressed fluid expands when leaving nozzle 34 into expansion area 36 causing a significant reduction in temperature. The heat absorbed in the expansion process reduces the surface temperature of external housing 14 causing exhaust fluid from hydraulic motor 30 and drilling head 24 along with melted ice to freeze. Threading 37 provides a greater surface area to extract heat from the fluid between external housing 14 and borehole 42 and also provides gripping surface once the exhaust fluid is frozen.
As indicated previously, a clevis 38 may be fixed on deployment end 18 of external housing 14 with provision to receive a tow line or cable etc.
Referring now to FIG. 2, a front view of a deployment sled 50 is illustrated as having frame members 52 and ballast tanks 54A through 54D. Mounted on a lower support frame 56 is a track 58 and continuous link chain drive 60. Track 58 is adapted for deployment of ice drill 12 and has brackets 62A and 62B (see FIG. 3) to guide ice drill 12 in track 58. Brackets 62A and 62B may be standard brackets attached to chain drive 60 to move drill 12 into iceberg 13 as borehole 42 is drilled. As ice drill 12 advances, bracket 62A releases and drill 12 is supported by borehole 42 and bracket 62B.
Illustrated in phantom above deployment sled 50 is a remotely operated vehicle 64. Remotely operated vehicle 64 may be of any type currently used in the art, the only requirement being that it may be adapted to grip onto deployment sled 50 without greatly restricting its maneuverability.
Referring now to FIG. 3, side view of the deployment sled of FIG. 2 illustrates ballast tanks 54A through 54D as running the full length of deployment sled 50. As ice drill 12 is deployed into the ice mass or iceberg which is being drilled, the weight of the deployment system comprising remotely operated vehicle 64 and deployment sled 50 is reduced in weight. To prevent dipping or pitching of deployment sled 50, ballast is released to maintain a predetermined bouyancy and to assure the deployment of ice drill 12 on a generally horizontal plane. Ballast release may be controlled electrically by a gyroscope (not shown) or the like. Ballast is released automatically when the pitch or slope of deployment sled 50 exceeds a predetermined amount.
Referring now to FIGS. 4A through 4C, deployment of ice drill 12 and its use as an anchor for towing purposes is illustrated. In FIG. 4A remotely operated vehicle 64 approaches iceberg 13 with deployment sled mounted thereunder. Ice drill 12 is illustrated as mounted on deployment sled 50 having deployment end 18 with clevis 38 mounted to the rear of deployment sled 50 and drill head end 20 mounted towards the front of sled 50. A tow line 70 is attached to clevis 38 to provide a towing connection between ice drill 12 and a marine vessel (not shown). Water lines 26 and 28 and compressed fluid line 32 are connected to tow line 70 in a manner that allows all tension between clevis 38 and a marine vessel to be absorbed by tow line 70. A tether line 72 is attached to remotely operated vehicle 64 in the event of malfunction of the controls. In the event that remotely operated vehicle 64 malfunctions, the tether line 72 may be used to retrieve remotely operated vehicle 64 once ice drill 12 is in place.
FIG. 4B illustrates ice drill 12 as having initiated borehole 42. Ballast from ballast tanks 54A through 54D has been released to permit maintaining ice drill 12 in a generally horizontal plane. In FIG. 4C, ice drill 12 has been deployed and has drilled a borehole 42. Ice drill 12 proceeded into iceberg 13 a predetermined distance such that clevis 38 extends out of the surface of iceberg 13. A compressed fluid is fed through fluid line 32 to expansion area 36 through nozzle 34 to provide quick freezing of external housing 14 of ice drill 12 into borehole 42. Remotely operated vehicle 64 together with deployment sled 50 is retrieved, leaving ice drill 12 having tow line 70 attached to clevis 38 solidly anchored into iceberg 13. In FIGS. 4A through 4C, ice drill 12 is illustrated as being deployed significantly below the surface of the water in which ice mass or iceberg 13 is floating. For best results, ice drill 12 is deployed in a horizontal plane on which the approximate center of gravity of iceberg 13 is located. Thus, iceberg 13 may be towed by exerting a pulling force on tow line 70 with a minimum amount of rolling and drag to provide additional safety and less stress on the towing vehicle.
FIGS. 5A through 5C illustrate an iceberg identification system. FIG. 5A is similar to FIG. 4A differing only in the line attached to clevis 38. Line 74 attached to clevis 38 is preferably a much lighter nylon line attached to an identification balloon 76. Remotely operated vehicle 64 together with deployment sled 50 and ice drill 12 are operated much in the same manner for an ice identification system as for the ice towing system. However, clevis 38 is of a much smaller size to permit its entrance into borehole 42. Ice drill 12 is placed approximately 100 to 120 feet inside iceberg 13 to assure that line 74 remains attached to iceberg 13 despite a significant amount of melting over a period of several weeks.
Identification balloon 76 may either use an active or a passive identification system. In the active identification system, a transmitter (not shown) is attached to identification balloon 76 to continually transmit a signal, preferably in the radio frequency range. By assigning a distinct radio frequency to each of a plurality of icebergs, acurate monitoring of individual icebergs is possible.
For a passive identification balloon, balloon 76 may be coated with a metalic foil of a type which will reflect microwaves such as radar. Although iceberg 13 will not be apparent on a radar sweep of the area, balloon 76, when covered with a metallic foil, will provide a positive indication of the location of iceberg 13. If identification balloon 76 becomes detached from iceberg 13, detachment is determined by the height of balloon 76.
As illustrated in FIG. 5C, ice drill 12 has been deployed approximately 100 feet into iceberg 13 while identification balloon 76 remains attached to clevis 38 through line 74. As iceberg 13 travels through the water, it will be constantly melting. As indicated previously, the ice below the surface of the water and above the surface of the water will melt at different rates, depending on whether the air or water is warmer. As such, iceberg 13 will occassionally roll due to the uneven melting. Line 74 is provided with enough length to allow identification balloon 76 to remain above the surface of the water despite rolling and shifting of iceberg 13. Identification balloon 76 is preferably filled with a lighter than air gas such as hellium. By constructing identification balloon 76 in a manner similar to weather balloons, a useful life of several months is assured.
As illustrated in FIG. 5B, ice drill 12 may be deployed in iceberg 13 at any location whereas in FIGS. 4A through 4C, ice drill 12 must be deployed in approximately the same horizontal plane as the center of gravity of iceberg 13 for towing purposes.
Referring now to FIG. 6, a modified ice drill 80 is illustrated as being similar to ice drill 12 differing only insofar as external housing 14 contains a bore packer 82 mounted close to drill head end 20. Drill head end 20 contains a vertical drill nozzle 84 in addition to drill head 24. Five fluid lines instead of three lines are illustrated as feeding ice drill 80. In addition to water lines 26 providing fluid flow to drill head 24 and hydraulic fluid lines 28 to hydraulic motor 30, fluid line 86 is illustrated to provide fluid flow to vertical drill nozzle 84, fluid line 88 is illustrated to provide expansion fluid to bore packer 82 and a high pressure line 90 is illustrated to supply internal pressure in iceberg 13.
Referring now to FIG. 7, a plan view of iceberg 13 is illustrated. Iceberg 13 has its center gravity 92 approximately half way between iceberg top 94 and iceberg bottom 96. In a system for splitting an iceberg, ice drill 80 must be deployed approximately one third of the height of iceberg 13 from bottom 96 in order to assure a simultaneous cracking above and below ice drill 80. This is due to the hydrostatic head of the water in which iceberg 13 is floating.
Referring now to FIGS. 8A through 8C, the deployment of an ice fracturing system is illustrated. Ice drill 80 is deployed into iceberg 13 to its approximate horizontal center at a predetermined depth, preferably two thirds of the distance from top 94 of iceberg 13. Upon reaching the approximate center of iceberg 13, fluid flow to drill head 24 is stopped and fluid flow to vertical drill nozzle 84 is begun to provide a vertical air space within iceberg 13. When a vertical area 98 is achieved, borepacker 82 is energized through fluid lines 88 to seal drill 80 into position. As illustrated in FIG. 8C, high pressure is provided through pressure line 90 to drill head end 20 of ice drill 80. This pressurizes vertical cavity 98 with air causing iceberg 13 to split. In the preferred embodiment, approximately 150 psig air pressure is used to cause iceberg 13 to fracture. Due to the hydrostatic head or external pressure of the water in which an iceberg 13 floats, fracturing will progress vertically upward approximately twice as rapidly as vertically downward. By initiating the fracture approximately one third of the distance from the bottom of iceberg 13, a fracture will reach top 94 and bottom 96 of iceberg 13 simultaneously, splitting iceberg 13 in two parts.
By fracturing a large iceberg, two smaller icebergs are produced which may easily be moved from a position where they endanger personnel and equipment by use of the ice towing system described previously.
The present invention illustrates a method and apparatus for drilling into an ice mass such as iceberg. In one example, a drill may be refrozen into position in the horizontal plane containing the center of gravity of the iceberg to permit towing the iceberg to a location where it no longer endangers personnel and equipment. In another example, a method and apparatus for identification of icebergs has been illustrated using an ice drill to provide a connection deep within an iceberg to provide a reliable monitoring system despite weather conditions. Additionally, a method and apparatus for providing a centralized area to internally pressurize an iceberg causing it to fracture has been illustrated. While the present invention has been described by way of preferred embodiment, it is to be understood that this was for illustration purposes only and that the present invention should not be limited thereto but only by the scope of the following claims.
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A method and apparatus is disclosed for moving a large mass of ice by anchoring a two line thereto. The tow line is connected to a marine vessel which tows the ice mass to a remote location distant from threatened equipment and personnel.
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FIELD AND BACKGROUND OF THE INVENTION
The present invention relates to electrical machinery and, more particularly, to brushless synchronous electrical generators and motors.
FIGS. 1A, 1B and 1C illustrate the terms used herein to define the geometries of rotary machines and their electrical windings. FIG. 1A shows a right circular cylinder 11, and the corresponding radial, azimuthal, and axial directions. As used herein, a "toroidal" winding is a winding, around a cylinder or torus, that is always perpendicular to the axial direction, and a "poloidal" winding is a winding that is at least partly parallel to the axial direction. FIG. 1B shows a torus 12 partially wound with a toroidal winding 13. FIG. 1C shows a torus 14 partially wound with a poloidal winding 15.
In a conventional synchronous AC electric generator, the rotor winding is connected to a DC current source via rings and brushes. As the rotor is rotated, the magnetic field created by the DC current rotates along with the rotor, inducing an AC electromagnetic force (EMF) in the stator winding. The same design is commonly used for synchronous electric motors: AC current in the stator winding creates a rotating magnetic field that interacts with the rotor's direct magnetic field, causing the rotor armature to rotate.
This design suffers from several inefficiencies. First, the rings and the brushes wear out over time and must be replaced. Second, parts of the stator winding, called "winding ends", protrude beyond the armature. These winding ends do not participate in the generation of electrical current in a generator, or in the generation of torque in a motor; but, unless the windings are made of superconductors, the winding ends contribute to resistance losses. In addition, the associated magnetic fields create eddy currents in electrical conductors outside of the armatures. These eddy currents are an additional drain on the power output of a generator or the power input of a motor.
The reason that rings and brushes are needed in the conventional synchronous machine design is to provide electrical power from a stationary DC current source to a moving rotor winding. There also are brushless designs, one of which, a synchronous induction machine, is illustrated schematically in cross-section in FIG. 2. An axially slotted cylinder 32, made of a ferromagnetic material such as iron, is rigidly mounted on a shaft 30, and rotates within a stationary armature 34. Armature 34 is geometrically in the form of an annulus, with a cylindrical central hole to accommodate slotted cylinder 32, and an interior equatorial slot to accommodate an annular, toroidally wound coil 36. In cross section, armature 34 looks like two opposed U's, as shown. What appear as the arms of the U's are actually two toroidal disks. A set 38 of windings are wound poloidally in slots on the inner periphery of these two disks. Conventionally there are three interleaved windings in set 38, making the synchronous induction machine of FIG. 2 a three-phase machine.
A DC current is supplied to toroidal coil 36, creating a magnetic field around slotted cylinder 32 and windings 38. Because cylinder 32 is slotted and ferromagnetic, as cylinder 32 rotates, the geometry of the magnetic field changes, inducing an AC EMF in poloidal windings 38. Conversely, an AC current introduced to poloidal windings 38 generates a time-varying magnetic field that applies a torque to cylinder 32, causing cylinder 32 to rotate.
The design of FIG. 2 eliminates the need for rings and brushes, but still has the inefficiencies associated with having winding ends that protrude outside the effective zone of electromagnetic induction. In addition, this design is inherently wasteful of space. Coils 36 and 38 must be separated spatially (as shown schematically in FIG. 2) to minimize eddy current losses.
There thus is a widely recognized need for, and it would be highly advantageous to have, an electrical machine (generator or motor) with only stationary windings, arranged geometrically for maximum efficiency.
SUMMARY OF THE INVENTION
According to the present invention there is provided an electrical machine including: (a) a stator armature including a number of magnetically interactive axial bars; (b) a substantially toroidal annular winding, rigidly attached to the stator armature and having two lateral sides; (c) a rotor including: (i) a shaft concentric with and extending axially through the annular winding and free to rotate therewithin, and (ii) a magnetically interactive rotor member, rigidly attached to the shaft, and including two projections extending radially outward from the shaft, each of the projections sweeping past the axial bars and past at least a portion of one of the lateral sides of the winding as the shaft rotates.
According to the present invention there is provided an electrical machine including: (a) a stator armature, including two sets of magnetically active L-shaped poles, each of the L-shaped poles having a radial leg and an axial leg meeting at an elbow, the radial leg extending radially outward from the elbow, the axial leg extending axially from the elbow, the L-shaped poles of a first of the two sets being positioned azimuthally around the armature at substantially equal angular spacings, the L-shaped poles of a second of the two sets, equal in number to the L-shaped poles of the first set, also being positioned azimuthally around the armature at the substantially equal angular spacings, interleaved azimuthally with the L-shaped poles of the first set, with the axial legs of the L-shaped poles of the first set pointing axially opposite to the axial legs of the L-shaped poles of the second set; (b) a substantially toroidal annular winding, rigidly attached to the stator armature and having two lateral sides; and (c) a rotor including: (i) a shaft concentric with and extending axially through the annular winding and free to rotate therewithin, and (ii) a magnetically interactive rotor member, rigidly attached to the shaft, and including two projections extending radially outward from the shaft, each of the projections sweeping past at least a portion of one of the lateral sides of the winding as the shaft rotates.
According to the present invention there is provided an electrical machine including: (a) a stator armature including a number of magnetically interactive stator cores; (b) a substantially toroidal annular inner winding, rigidly attached to the stator armature and having two lateral sides, each of the stator cores extending radially outward from the inner winding, the stator cores being positioned azimuthally around the inner winding at substantially equal angular separations; and (c) a rotor including: (i) a shaft concentric with and extending axially through the inner winding and free to rotate therewithin, and (ii) a magnetically interactive rotor member, rigidly attached to the shaft, and including two projections extending radially outward from the shaft, each of the projections sweeping past at least a portion of one of the lateral sides of the winding as the shaft rotates.
According to the present invention there is provided an electrical machine including: (a) a stator armature including a magnetically interactive ring; (b) a substantially toroidal annular inner winding, rigidly attached to the stator armature substantially concentrically with the ring and having two lateral sides; (c) a rotor including: (i) a shaft concentric with and extending axially through the inner winding and free to rotate therewithin, and (ii) a magnetically interactive rotor member, rigidly attached to the shaft, and including two projections extending radially outward from the shaft, each of the projections sweeping past at least a portion of one of the lateral sides of the winding and past at least a portion of the ring as the shaft rotates; and (d) at least one stator winding, wound poloidally around the ring.
According to the present invention there is provided an electrical machine including: (a) a stator armature; (b) a substantially toroidal annular inner winding, rigidly attached to the stator armature, and having two lateral sides; and (c) a rotor including: (i) a shaft concentric with and extending axially through the inner winding and free to rotate therewithin, and (ii) a magnetically interactive rotor member, rigidly attached to the shaft, and including two projections extending radially outward from the shaft, each of the projections sweeping past at least a portion of one of the lateral sides of the winding as the shaft rotates, at least one of the projections including a plurality of substantially parallel sheets of a magnetically interactive material separated by at least one insulating material.
As used herein, the term "magnetically interactive material" means a material that interacts strongly with a magnetic field, for example a ferromagnetic material or a ferrimagnetic material. Parts of the present invention that are made of, or include, a magnetically interactive material are herein called "magnetically interactive". The preferred magnetically interactive materials of the present invention are soft ferromagnetic materials such as magnetic steel.
The present invention is similar to the synchronous induction motor of FIG. 2, but the windings and armatures are arranged so that all, or almost all, of the length of the windings actively participate in the energy transformation process. One of the windings is wound around a shaft, with a gap between the shaft and the winding, so that the winding can remain stationary as the shaft rotates therewithin. A projection, made of a magnetically interactive material, is fixed to the shaft next to the winding. The shaft and the projection fixed thereto constitute a rotor. As the rotor rotates, the projection is swept past the winding. The radial extent of the projection varies azimuthally, so that the geometry of a magnetic field around the shaft changes as the shaft rotates, or conversely, a time-varying magnetic field near the shaft exerts a torque on the projection. Because of the intimate geometrical association of this winding with the rotor, it is referred to herein as the "inner" winding.
The inner winding, and one or more "stator" windings, are rigidly attached to a stator armature that surrounds the rotor. This rigid attachment may be indirect: for example, in one embodiment of the present invention, a stator winding is rigidly connected to the stator armature and a inner winding is rigidly connected to the stator winding. The stator armature is made at least in part of a magnetically interactive material, to help shape and concentrate the magnetic fields associated with the windings.
Thus, the present invention succeeds in providing a compact, efficient brushless electrical machine whose windings are fully exploited. The problems addressed herein also have been addressed by Torok in U.S. Pat. No. 5,047,680. Torok's solution, however, requires the use of permanent magnets, and therefore is inherently limited to low power applications. In addition, Torok's permanent magnets are mounted on his stator as circumferential rings that are mutually staggered, whereas his toothed rotor rings, which rotate within the rings of permanent magnets, are mutually aligned, so that when one rotor ring is aligned with the surrounding ring of permanent magnets, thereby being in a position of low reluctance, the other rotor rings are staggered with respect to the rings of permanent magnets that surround them, and are therefore in positions of high reluctance. This reduces the efficiency of Torok's design.
A further advantage of the electrical machine of the present invention over the machine of the prior art is that the stator windings of the present invention require less insulation than the stator windings of the prior art. In a conventional synchronous AC generator, for example, the stator winding is inserted into slots in the stator armature, and must be insulated on all sides from the voltage difference (whatever the output of the generator is) between the winding and the armature. Stator windings of the present invention are wound either helically, or poloidally as illustrated in FIG. 1C, on the surfaces of the stator armatures, and so must be insulated from the output voltage difference of the generator only on the sides that face the stator armatures. The insulation between lengths of stator winding needs to withstand a much smaller voltage difference, and so may be much thinner than the insulation between the windings and the armature.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein:
FIG. 1A (prior art) illustrates the definition of geometric terms used herein;
FIG. 1B (prior art) illustrates the definition of the term "toroidal" as used herein;
FIG. 1C (prior art) illustrates the definition of the term "poloidal" as used herein;
FIG. 2 (prior art) is a schematic cross-section of a synchronous induction machine;
FIG. 3 is an axial cross-section through a first embodiment of the present invention;
FIG. 4 is a transverse cross-section through the embodiment of FIG. 3;
FIG. 5 is an axial cross-section through a second embodiment of the present invention;
FIG. 6 is an end-on view of the embodiment of FIG. 5;
FIG. 7A is a transverse cross-section through a rotor of a third embodiment of the present invention;
FIG. 7B is a transverse cross-section through a third embodiment of the present invention;
FIG. 8 is an axial cross-section through the embodiment of FIG. 7B;
FIG. 9 is an axial cross-section through a variant of the embodiment of FIG. 7B;
FIG. 10 is a partial exploded perspective view of a fourth embodiment of the present invention.
FIG. 11 is an axial cross section through the embodiment of FIG. 10;
FIG. 12 is an axial cross section through a variant of the embodiment of FIGS. 3 and 4;
FIG. 13 is a perspective view of a variant of the rotor of the embodiment of FIGS. 3 and 4;
FIG. 14 is an exploded side view of another variant of the rotor of the embodiment of FIGS. 3 and 4;
FIG. 15 is an axial cross section of the rotor of the embodiment of FIGS. 3 and 4 with laminated toothed disks.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention is of a brushless synchronous rotary electrical machine in which the armature and winding geometries are selected to maximize the interaction of the magnetic fields created by the windings. The present invention can be used to generate AC power, or to convert AC power to rotary motion, more efficiently than presently known electrical machines.
Referring now to the drawings, FIG. 3 is an axial cross-sectional view of a relatively simple embodiment of the present invention, and FIG. 4 is a transverse cross-sectional view through the embodiment of FIG. 3 along line A--A. A cylindrical shaft 42 is mounted on bearings 44 within a housing 40. Shaft 42 is free to rotate within housing 42 on bearings 44. Rigidly attached to shaft 42 is a rotor armature that includes two outer annular disks 52 and 53, and an inner annular cylinder 54. The rotor armature is a spindle-shaped structure: the portions of outer disks 52 and 53 that project radially outward beyond inner cylinder 54 define between them an equatorial slot. Rigidly attached to the interior of housing 40, and complementary to the rotor armature, is a stator armature that includes two outer annular disks 62 and 63, and an inner annular cylinder 64. The portions of outer disks 62 and 63 that project radially inward beyond inner cylinder 64 define between them an equatorial slot opposite the equatorial slot of the rotor armature. The rotor armature and the stator armature are made of a magnetically interactive material.
Outer disk 52 has a perimeter 56, represented in FIGS. 3 and 4 by dotted lines. Outer disk 62 has an inner perimeter 66, also represented in FIGS. 3 and 4 by dotted lines. Teeth 58 of outer disk 52 project radially outward from perimeter 56. A like number of teeth 68 of outer disk 62 project radially inward from perimeter 66. Outer disks 53 and disk 63 have similar teeth projecting outward and inward, respectively, from the perimeter and inner perimeter, respectively, thereof.
An annular, toroidal stator winding 76 is rigidly attached to the inner perimeter of cylinder 64. An annular, toroidal inner winding 70, having two lateral sides 72 and 74, is rigidly attached to the inner perimeter of stator winding 76. As shaft 42 rotates on bearings 44, outer disk 52 sweeps past lateral side 72 of inner winding 70 and outer disk 53 sweeps past lateral side 74 of inner winding 70.
To use the device of FIGS. 3 and 4 as a generator, DC current is provided to stator winding 76, and shaft 42 is rotated by an external means. The magnetically interactive rotor and stator armatures concentrate the magnetic field created by the DC current. As teeth 58 move past teeth 68, the magnetic field is made to vary periodically, inducing an AC EMF in inner winding 70.
The device of FIGS. 3 and 4 is not useable as such as a motor, because it is too symmetrical. For example, whenever teeth 58 are exactly opposite teeth 68, and whenever teeth 58 are exactly in-between teeth 68, all forces are radial and no torque is applied to shaft 42. One way to establish the necessary asymmetry is to mount three units of the type shown in FIGS. 3 and 4 in tandem on shaft 42. The three units have their stator armature teeth aligned, but the rotor armature teeth of the second unit are shifted azimuthally with respect to the rotor armature teeth of the first unit by one-third of the tooth pitch (the angle spanned by a tooth and an adjacent slot), and the rotor armature teeth of the third unit are shifted azimuthally with respect to the rotor armature teeth of the second unit by one-third of the tooth pitch. If the stator and rotor armature outer disks all have a number P of teeth, then the tooth pitch is 2π/P radians, so the rotor armature teeth of the second unit are shifted by 2π/3P radians with respect to the rotor armature teeth of the first unit, and the rotor armature teeth of the third unit are shifted by 2π/3P radians with respect to the rotor armature teeth of the second unit. Furthermore, the AC current supplied to the inner winding of the second unit is one-third of a cycle out of phase with the AC current supplied to the inner winding of the first unit, and the AC current supplied to the inner winding of the third unit is one-third of a cycle out of phase with the AC current supplied to the inner winding of the second unit. The result is that the net magnetic interaction between teeth 58 and 68 is attractive as teeth 58 approach teeth 68 and repulsive as teeth 58 move away from teeth 68. The same effect also can be obtained using only two units with AC currents that are one-quarter of a cycle out of phase from each other. As the rotor teeth approach the stator teeth, the AC currents in the inner windings flow in a direction that creates an attraction between the teeth. As the rotor teeth move away from the stator teeth, the AC currents in the inner windings flow in a direction that creates a repulsion between the teeth.
The embodiment of FIGS. 3 and 4 is particularly useful as a high frequency generator, as a low speed motor, and as a stepping motor. In a stepping motor configuration with three units in tandem, for example, inner winding 70 and stator winding 76 of each unit are connected in series. Square pulses of DC current are supplied alternately to the first unit, the second unit, and the third unit. Whenever a unit receives a pulse, the rotor teeth 58 and stator teeth 68 of the unit move into alignment. Thus, each DC pulse causes common shaft 42 to rotate one angular step of one third of a tooth pitch. This stepping motor develops high torque for small angular steps, unlike the prior art stepping motors, which can deliver either high torque or small angular steps, but not both.
FIG. 12 shows an axial cross-sectional view of a variant of the design of the embodiment of FIGS. 3 and 4, suitable for use as a generator. In this variant, disks 62, 63 and 64 of the stator armature are replaced by axial bars 64' that are made of a magnetically active material and that are disposed circumferentially around the inner periphery of housing 40. There are as many axial bars 64' as there are teeth on each of outer disks 52' and 53' of the rotor armature. Outer disks 52' and 53' extend radially outward into the space that is occupied by outer disks 62 and 63 in FIGS. 3 and 4.
The magnetically interactive projections of the rotor of this embodiment need not be toothed disks. FIG. 13 is a perspective view of a variant of the rotor in which the projections are legs 304 of four C-cores 300 such as are used in transformers. C-cores 300 are attached to shaft 42 at the shanks 302 thereof, and legs 304 project radially away from shaft 42. One important aspect of the construction of C-cores 300 is that they are laminated structures, made of substantially parallel sheets 310 of a magnetically interactive metal, such as magnetic steel, separated by layers 312 of an insulator, such as epoxy glue. This laminated structure of alternating electrical conductors and electrical insulators suppresses the formation of power-wasting eddy currents. One way of fabricating laminated C-cores 300 is to apply epoxy glue to one side of a magnetic steel strip, roll up the strip, wait for the glue to set, and cut the rolled up strip longitudinally in half.
FIG. 14 is an exploded side view of another variant of the rotor of this embodiment. To each end of shaft 42 is attached a disk 340 made of a magnetically noninteractive material. Each disk 340 is provided with radial slots 342 that accommodate radially projecting laminated fingers 330. Fingers 330 are made of alternating layers of magnetic steel 310 and epoxy glue 312, as shown in horizontal section A--A of upper left finger 330. Fingers 330 constitute the magnetically active projections of this variant of the rotor. Within slots 342 are ridges 344 that fit into grooves 314 on the backs of fingers 330. The mechanical function of disk 340 is to secure fingers 330 against centrifugal force, and to transfer torque from shaft 42 to fingers 330 (if the rotor is used in a generator) or from fingers 330 to shaft 42 (if the rotor is used in a motor).
Disks 340 may be made of an insulating material or of an electrically conductive but magnetically noninteractive material. If disks 340 are made of an electrically conductive material, then disks 340 are provided with radial slits, to suppress eddy currents. Like C-cores 300 and fingers 310, annular cylinder 54 preferably is laminated to suppress eddy currents. A wound and glued steel strip, similar to the intermediate in the production of C-cores 300, may be used as cylinder 54.
A similar design may be used for toothed disks 52 and 53 of FIGS. 3 and 4. FIG. 15 is an axial cross section of the rotor of FIGS. 3 and 4 showing disks 52 and 53 as laminated structures of magnetic steel 310 and epoxy glue 312. Cylinder 54 is shown laminated as described above. Note that the ends of cylinder 54 are tapered, and disks 52 and 53 have conical central holes to accommodate the tapered ends of cylinder 54. Disks 52 and 53 are fabricated by stamping identical toothed disks from sheet steel, gluing the disks together using, for example, epoxy glue, and machining the central holes of the disks on a lathe. The ends of cylinder 54 may be tapered similarly. Alternatively, cylinder 54 may be fabricated by winding a trapezoidal steel strip; and disks 52 and 53 may be fabricated by stamping out toothed steel disks having central holes of successively increasing diameters, and gluing the disks together using epoxy glue.
Although the description above speaks of AC current flowing through winding 70 and DC current flowing through winding 76, it will be appreciated that the devices of FIGS. 3, 4 and 12 also may be used with DC current flowing through winding 70 and AC current flowing through winding 76. It also will be appreciated that outer disks 52, 53, 62 and 63 need not have teeth 58 and 68 all the way around perimeters 56 and 66, in motors such as torquers in which the angular range of the motion of shaft 42 is inherently limited to less than a full circle.
One drawback of the design of the embodiment of FIGS. 3 and 4 is that, in generator mode, less than half of the full range of magnetic flux created by the stator winding is used to create EMF in the inner winding. In other embodiments of the present invention, the geometries of the rotor and the stator are configured so that the magnetic field through the inner winding is fully exploited.
FIGS. 5 and 6 show one such design, the example of the design illustrated being a four pole machine. FIG. 5 is an axial cross-section through the embodiment. FIG. 6 is an end-on view of the embodiment. In both Figures, neither the housing nor the bearings are shown, for clarity. In FIG. 6, the windings are not shown either, also for clarity.
To a shaft 80 are rigidly attached two rectangular bars 84 and 84'. Bar 84' is mounted perpendicular to bar 84. Also rigidly attached to shaft 80 is an annular cylinder 82 connecting bars 84 and 84'. Bars 84 and 84' and cylinder 82 are made of magnetically interactive materials. Shaft 80, bars 84 and 84', and cylinder 82 together constitute the rotor of the embodiment of FIGS. 5 and 6.
The stator armature of the embodiment of FIGS. 5 and 6 is a circumferential ring 88 to which are attached four identical L-shaped poles 90, 90', 100, and 100', hereinafter referred to for brevity as "L"s. Each L consists of an axial leg and a radial leg joined at an elbow at a right angle. L 90 consists of an axial leg 92 and a radial leg 94 meeting at an elbow 96. L 90' consists of an axial leg 92' and a radial leg 94' meeting at an elbow 96'. L 100 consists of an axial leg 102 and a radial leg 104 meeting at an elbow 106. L 100' consists of an axial leg 102' and a radial leg 104' meeting at an elbow 106'. The L's are connected to ring 88 at the ends of their radial legs opposite their elbows. Both the L's and ring 88 are made of magnetically interactive materials. An annular, toroidal stator winding 116 is rigidly attached to the inner perimeter of ring 88. An annular, toroidal inner winding 110, having two lateral sides 112 and 114, is rigidly attached to the inner surfaces of the L's. As shaft 80 rotates, bar 84 sweeps past lateral side 112 of inner winding 110 and bar 84' sweeps past lateral side 114 of inner winding 110 without contacting inner winding 110.
For a given current direction in stator winding 116, all the L's that face in one axial direction are N-poles, and all the L's that face the other axial direction are S-poles. In this way, each side of circumferential ring 88 is given heteropolarity (N-S-N-S). For example, if the elbows on one axial side are N-poles, then the ends of the axial legs on that side are S-poles, while the elbows on the other axial side are S-poles and the ends of the axial legs on the other axial side are N-poles.
To use the device of FIGS. 5 and 6 as a generator, DC current is supplied to stator winding 116 and shaft 80 is rotated. As bars 84 and 84' rotate, the magnetic field created by the DC current is made to vary periodically, inducing an AC EMF in inner winding 110. The magnetic flux in this device has two branches. Suppose for definiteness that the DC current in stator winding 116 flows into the plane of FIG. 5 at the top of FIG. 5 and out of the plane of FIG. 5 at the bottom of FIG. 5, i.e., clockwise in FIG. 6. In the orientation of bars 84 and 84' relative to the L's shown in FIGS. 5 and 6, magnetic flux of the first branch enters leg 94 from the top of ring 88, enters elbow 96 from leg 94, enters bar 84 from elbow 96 across the air gap therebetween, enters cylinder 82 from bar 84 (from left to right in FIG. 5), and enters bar 84' from cylinder 82. Magnetic flux of the second branch enters leg 94' from the bottom of ring 88, enters elbow 96' from leg 94', enters bar 84 from elbow 96' across the air gap therebetween, and joins the flux from the first branch in cylinder 82 from bar 84 and bar 84' from cylinder 82. The magnetic flux then splits again into two branches. The first branch enters elbow 106 from bar 84' across the air gap therebetween, enters leg 104 from elbow 106, and returns to ring 88 from leg 104. The second branch enters elbow 106' from bar 84' across the air gap therebetween, enters leg 104' from elbow 106', and returns to ring 88 from leg 104', where it joins the first branch. In short, in the orientation of FIGS. 5 and 6, bars 84 and 84' are linked by magnetic flux to the elbows of the L's. After the rotor is rotated by 90°, the ends of bar 84 are next to axial legs 102 and 102', and the ends of bar 84' are next to axial legs 92 and 92'. One branch of the magnetic flux enters leg 94 from the top of ring 88, enters elbow 96 from leg 94, enters leg 92 from elbow 96, enters bar 84' from leg 92, enters cylinder 82 from bar 84' (from right to left in FIG. 5), and enters one side of bar 84 from cylinder 82. The second branch of magnetic flux also enters leg 94' from the bottom of ring 88, enters elbow 96' from leg 94', enters leg 92' from elbow 96', enters bar 84' from leg 92', joins the first branch in cylinder 82 from bar 84' and separates from the first branch into the other side of bar 84 from cylinder 82. The first branch of the magnetic flux then enters leg 102 from bar 84, enters elbow 106 from leg 102, enters leg 104 from elbow 106, and returns to ring 88 from leg 104. The second branch of the magnetic flux enters leg 102' from bar 84, enters elbow 106' from leg 102', enters leg 104' from elbow 106', and joins the first branch in ring 88 from leg 104'. In short, when the rotor is rotated by 90° with respect to the orientation of FIGS. 5 and 6, bars 84 and 84' are linked by magnetic flux to the axial legs of the L's. Thus, when the rotor is in the position shown in FIG. 5, the magnetic flux patterns above and below shaft 80 look like "O"s, and the magnetic field through inner winding 110 points to the right; whereas when the rotor is in the perpendicular position, with bar 84 horizontal and bar 84' vertical, the magnetic flux patterns above and below shaft 80 look like figure "8"s, and the magnetic field through inner winding 110 points to the left.
It will be appreciated that the design illustrated in FIGS. 5 and 6 is not inherently limited to two bars and four L-shaped poles. Any reasonable number of radially projecting poles can be rigidly attached at equal angular spacings around opposite sides of shaft 80 (including, in principle, one pole on each side, although such a design would be mechanically imbalanced), with the poles on one side interleaved with the poles on the other side when the machine is viewed end-on as in FIG. 6. (Bars 84 and 84' in the specific embodiment illustrated in FIGS. 5 and 6 are the equivalents of two poles at either side of shaft 80.) Around the two sides of the stator are attached as many L-shaped poles as there are radially projecting poles, also at equal angular spacings, and also mutually interleaved when the machine is viewed end-on.
It also will be appreciated that three units of the second embodiment can be connected in tandem to form a three-phase generator, and that two or more units can be connected, as in the first embodiment, to form an electric motor.
FIGS. 7A, 7B and 8 show an example of a third embodiment of the present invention, suitable for use as a three-phase AC generator, a three-phase motor or a synchronous power factor compensator. FIG. 7A is a transverse cross section through the rotor 130 of this embodiment. FIG. 7B is a transverse cross section through the embodiment. FIG. 8 is an axial cross section through the embodiment. The cross section of FIG. 8 is along cut B--B of FIG. 7B. FIG. 7B actually is a composite of a cross-section along cut C--C of FIG. 8 and an end-on view of the embodiment looking from the left side of FIG. 8. This particular example has two units of a two pole machine. As is explained below, two pole machine units of this design preferably are configured in pairs, whereas units of this design having two or more pairs of poles may be used individually.
Rotor 130 of this embodiment consists of a shaft 132 to which are attached four annular disks. FIG. 7A is a transverse cross section through one of the disks, showing that it is made of a first half-disk 134, of a magnetically interactive material, and a second half-disk 136, of a magnetically noninteractive material having the same density as the material of half-disk 134. The magnetically interactive half-disks are half-disks 134, 138, 144 and 148. The magnetically noninteractive half-disks are half-disks 136, 140, 142 and 146. Note that the orientation of the magnetically interactive half of the disks alternates along shaft 132 within each of the two units of this embodiment, with the second disk from the left having its magnetically interactive half 138 on the opposite side of shaft 132 from magnetically interactive half 134 of the leftmost disk, and the rightmost disk having its magnetically interactive half 148 on the opposite side of shaft 132 from magnetically interactive half 144 of the second disk from the right. The magnetically noninteractive half-disks are optional. Their purpose is to provide mechanical balance, if needed: within each disk, the magnetically noninteractive half balances the magnetically active half against unbalanced centrifugal forces; and the left side of the rotor of FIG. 8 is the mirror image of the right side of the rotor of FIG. 8 to balance the forces between the disks and the stator described below.
Rotor 130 rotates freely within a housing 120, supported on bearings 122. The portion of rotor 130 that is within housing 120 is made of a magnetically interactive material. Rigidly attached to the inner surface of housing 120 are two stator armatures. The left stator armature includes three stator cores 150, 152 and 154, spaced 120° apart from each other as shown in FIG. 7B, and connected by two circumferential rings 162 and 164. The right stator armature similarly includes three stator cores, 156, 158 and a third stator core not shown, spaced 120° apart from each other, and connected by two circumferential rings 166 and 168. The stator cores and the circumferential rings are made of magnetically interactive materials.
Helically wound around the six stator cores are six stator windings. Stator winding 190 is wound around stator core 150. Stator winding 192 is wound around stator core 152. Stator winding 194 is wound around stator core 154. Stator winding 196 is wound around stator core 156. Stator winding 198 is wound around stator core 158. The sixth stator winding, like the sixth stator core, is not shown in the Figures. Rigidly attached to the radially inward ends of the stator cores are two stationary, annular, toroidal inner windings, surrounding shaft 132. Inner winding 170 is attached to poles 150, 152 and 154. Inner winding 180 is attached to poles 156 and 158, and to the sixth pole that is not shown in the Figures. As rotor 130 rotates, magnetically interactive half-disk 134 sweeps past lateral side 172 of inner winding 170, magnetically interactive half-disk 138 sweeps past lateral side 174 of inner winding 170, magnetically interactive half-disk 144 sweeps past lateral side 182 of rotor winding 180, and magnetically interactive half-disk 148 sweeps past lateral side 184 of rotor winding 180. FIG. 7B, in addition to being a transverse cross section through cut C--C of FIG. 8, also shows how circumferential ring 164 and half-disks 138 and 140 would appear behind the cut, as seen from the left in FIG. 8.
To use the device of FIGS. 7A, 7B and 8 as a generator, DC current is supplied to rotor windings 170 and 180 and rotor 130 is rotated. The magnetically interactive stator armatures divert the magnetic field created by the DC current through the stator windings. As the magnetically interactive half-disks sweep past the stator windings, the direction in which the magnetic field is directed through the stator cores changes periodically, inducing AC EMFs in the stator windings.
Suppose for definiteness that the DC current in rotor winding 170 flows into the plane of FIG. 8 above shaft 132 and out of the plane of FIG. 8 below shaft 132, i.e., counterclockwise in FIG. 7B. The magnetic flux through rotor winding 170 is always directed to the left in FIG. 8. With rotor 130 oriented relative to the stator armatures as shown in FIG. 8, magnetic flux enters the radially inward end of stator core 150 from half-disk 134 across the air gap therebetween, enters the tops of rings 162 and 164 from the radially outward end of stator core 150, enters the radially outward ends of stator cores 152 and 154 from rings 162 and 164, and enters half-disk 138 from the radially inward ends of stator cores 152 and 154 across the air gaps therebetween. The magnetic flux through stator winding 190 is directed radially outward, at its maximum value; the magnetic flux through each of stator windings 192 and 194 is directed radially inward, at half of its maximum value.
Now rotate rotor 130, as seen in FIG. 7B, clockwise by 120°. Half-disk 134 now is adjacent to stator core 152, and half-disk 138 is adjacent to stator cores 150 and 154. Therefore, the magnetic flux through stator winding 192 now is directed radially outward, at its maximum value, while the magnetic flux through each of stator windings 190 and 194 is directed radially inward, at half of its maximum value. Rotating rotor 130 clockwise by another 120° brings half-disk 134 adjacent to stator core 154 and half-disk 138 adjacent to stator cores 150 and 152. Now, the magnetic flux through stator winding 194 is directed radially outward, at its maximum value, and the magnetic flux through each of stator windings 190 and 192 is directed radially inward, at half of its maximum value. Thus, as rotor 132 is rotated at a uniform angular speed, AC EMFs are induced in stator windings 190, 192 and 194 that are identical except for being shifted in phase relative to each other by one-third of a cycle.
As noted above, the example illustrated in FIGS. 7A, 7B and 8 includes two units of a two pole machine. It will be appreciated that the design illustrated in FIGS. 7A, 7B and 8 is not inherently limited to two pole machines whose rotors include magnetically active half-disks. In general, the rotor projections of this embodiment have magnetically active lobes, spaced at equal angular increments. (The specific embodiment shown in FIGS. 7A, 7B and 8 has one semicircular lobe per disk.) Correspondingly, each stator armature of this embodiment includes three times as many stator cores as there are magnetically active lobes in one projection. Each unit of the embodiment includes one stator armature flanked by two rotor projections. Within each unit, the magnetically interactive lobes of one projection are interleaved with the magnetically interactive lobes of the other projection when the unit is viewed end-on. If each disk has two or more magnetically active lobes, then a machine of this embodiment needs only one unit, not the two units shown in FIG. 8, because the forces within each unit are balanced.
FIG. 9 shows an axial cross-section through another variant of the two pole embodiment of FIGS. 7A, 7B and 8. In this variant, stator cores 150', 152', 156', 158' and two others not shown have a T-shaped cross section, and half-disks 134', 136', 138', 140', 142', 144', 146' and 148' are correspondingly smaller to accommodate the cross-bars of the T's. In this embodiment, the magnetic fluxes linking the stator cores and the half-disks are directed radially, as opposed to the embodiment of FIGS. 7A, 7B and 8, in which the magnetic fluxes linking the stator cores and the half-disks are directed axially. This variant is preferred in applications in which there is a limit on maximum rotor diameter.
FIGS. 10 and 11 show one unit of a two pole version of a fourth embodiment of the present invention. FIG. 10 is a partial exploded perspective view. FIG. 11 is an axial cross section. The rotor of this embodiment is identical to the rotor of the third embodiment as illustrated in FIGS. 7A, 7B and 8: to a magnetically interactive shaft 202 are rigidly attached two annular disks, one disk including a magnetically interactive half-disk 204 and a magnetically noninteractive half-disk 206, and the other disk including a magnetically interactive half-disk 210 and a magnetically noninteractive half-disk 208. The stator armature of this embodiment is a circumferential ring 220 made of a magnetically interactive material. For example, ring 220 may be a steel strip bent in the shape of a circle as shown, a hexagon, or any other suitable closed figure. Three stator windings 222, 224 and 226 are wound poloidally around three different sections of ring 220. Preferably, each section occupies an azimuthal span of 120° around ring 220. Shaft 202 is mounted on bearings 232 in a housing 230. Stator windings 222, 224 and 226, as well as ring 220, are attached to housing 230 as shown. A stationary inner winding 240, substantially identical to the inner winding of the third embodiment, is attached to stator windings 222, 224 and 226 as shown. For clarity, housing 230, bearings 232 and inner winding 240 are not shown in FIG. 10; and only cross sections of stator windings 222 and 224 are shown in FIG. 11.
With an appropriately directed magnetic field in the inner winding, and with the disks positioned as shown in FIG. 10, magnetic flux enters the top half of ring 220 from half-disk 204, and enters half-disk 210 from the bottom half of ring 220. Within ring 220, magnetic flux points in a clockwise direction on the right side of ring 220 and in a counterclockwise direction on the left side of ring 220. As shaft 202 is rotated, this pattern of magnetic flux rotates along with shaft 220, inducing a three-phase AC EMF in windings 222, 224 and 226.
As in the case of the third embodiment, the most general form of the rotor projections of the fourth embodiment includes magnetically active lobes spaced at equal angular increments. Within each unit of the embodiment, the magnetically interactive lobes of one projection are interleaved with the magnetically interactive lobes of the other projection when the unit is viewed end-on. There are three times as many stator windings as there are lobes per projection, each stator winding occupying an equal azimuthal portion of ring 220. Also as in the case of the third embodiment, only the two pole embodiment needs to be configured as two tandem units, for mechanical balance; units with three or more poles may be used individually.
To configure the fourth embodiment of the present invention as a motor, the stator windings are supplied with AC current, and the inner winding of each unit is supplied with a DC current. The interaction between the static magnetic fields of the inner windings and the time-varying magnetic fields of the stator windings provides a torque that turns the rotors. Because the lobes on either end of each unit interleave, there always is a net torque on the rotors.
While the invention has been described with respect to a limited number of embodiments, it will be appreciated that many variations, modifications and other applications of the invention may be made.
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A brushless synchronous rotary electrical machine comprises stationary stator and "rotor" windings. Only the rotor moves. The rotor winding is a stationary helical winding, concentric with the rotor shaft and attached to the stator armature. Variation in time of the magnetic field associated with the rotor is provided by one or more magnetically interactive (ferromagnetic or ferrimagnetic) projections from the rotor that sweep past the sides of the rotor winding as the shaft rotates. Because all windings are stationary, brushes and rings are not needed. The geometries of the rotor, of the stator windings, and of the magnetically interactive part of the stator armature are arranged so that the entire length of the wire in the windings participates in the generation of AC current (in a generator) or torque (in a motor), and so that loss of power to eddy currents is minimized. In preferred embodiments of the machine as a generator, the geometries of the rotor and of the stator armature are chosen to ensure that the magnetic field through the AC winding changes sign cyclically.
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CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation of international application PCT/AT96/00107, filed Jun. 14, 1996 which designated the United States.
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a method for producing disposable, thin-walled molded articles, such as cups, plates, fast-food packages, trays, flat sheets and the like by applying a starch-based baking composition onto the lower mold part of a multi-part, preferably two-part mold, baking and conditioning to a moisture content of 6% by weight to 22% by weight, the baking composition, in addition to water and a starch or starch mixtures and/or flour or flour mixtures and/or starch derivatives, contains a release agent, namely one or more medium- or long-chained, optionally substituted fatty acids and/or salts thereof and/or acid derivatives thereof, such as acid amides, and/or a polymethyl hydrogen siloxanes, and optionally:
thickening agents, such as swelling starch, pregelatized starch or baking waste, and/or guar flour, pectin, carob seed flour, carboxymethylcellulose and/or gum arabic;
fibrous materials, such as cellulose-rich raw materials, plant materials, fibers of plastic, glass, metal and carbon materials;
nonfibrous filler materials, such as calcium carbonate, coal, talcum, titanium dioxide, silica gel, aluminum oxide, shellac, soy protein, powdered wheat gluten, powdered egg white from chicken eggs, powdered casein;
powdered pigments;
a zirconium salt, preferably ammonium zirconium carbonate and/or ammonium zirconium acetate, as structural stabilizers;
preservatives and antioxidants.
Molded articles produced with these prior art baking compositions still have a number of disadvantages. For instance, at relatively low humidity, approximately below 50%, in conjunction with slow moisture desorption, these molded articles exhibit ever-increasing brittleness.
This makes itself felt especially disadvantageously in two areas:
1. Over the course of long-term storage and in heated rooms during the winter, the relative humidity is often below 20%, or even below 10%.
2. In molded articles or molded article parts that are exposed to increasing bending strain: as an example, drinking glasses (compression strain during use) or two-piece hinged molded articles ("clamshells"), where the hinge is likely subjected to repeated opening and closing operations (requiring increased flexibility).
Another disadvantage of molded articles of starch, precisely in comparison with cellulose-based materials (paper, cardboard) is the virtually complete loss of tear strength if they become soaked.
Polyvinyl alcohol is a biodegradable synthetic polymer that has long been used for water-soluble films, in paper processing, and in textile impregnation. Its use together with types of starch is known from the production of cast films and from extrusion technology.
U.S. Pat. No. 3,312,641 to Young teaches that films cast from aqueous solution and comprising amylose or amylose-rich starch and polyvinyl alcohol, have greater tensile strength and are more stretchable, at 23 and 50% relative humidity, than pure starch films.
U.S. Pat. No. 3,949,145 to Otey describes similar improvements in sheets made of normal cornstarch (27% amylose), used jointly with formaldehyde for cross-linking.
U.S. Pat. No. 5,095,054 to Lay et al. and European Patent Application EP 0 400 531 A1 (Bastioli et al.) describe the melt extrusion of starch, water and polyvinyl alcohol to form a homogeneous melt. These references state that improved dimensional stability at high humidity is found.
According to U.S. Pat. No. 4,863,655 to Lacourse, a homogeneous melt of amylose-rich starches, water and up to 10% polyvinyl alcohol is again extruded. The result obtained is an expanded foam (filler chips).
Methods for producing foamed molded articles of starch from baking compositions by gelatinization without creating homogeneous melts beforehand are known from U.S. Pat. No. 5,376,320 to Tiefenbacher et al. (corresp. European Patent Disclosure EP 513 106 B1).
A decrease in brittleness at relatively low humidity and an increase in flexibility and water resistance of such molded articles with starch is desirable and could greatly expand their fields of application.
However, the art has had reservations with regard to the well-known adhesive action of polyvinyl alcohol.
In a baking method at temperatures of around 200° C., the question of thermal stability and formation of residues on the hot mold surfaces must also be taken into account.
Not least because of the known rheological properties of the starch--"dilatory" viscous behavior with the danger of seizing of pumps from friction at high viscosity, for instance--the use of high-viscosity additives, such as polyvinyl alcohol, appears inadvisable. On the other hand, with major dilution with water in this process technique and an attendant decrease in the proportion of dry substance and increase in the water "leavening" in the baking compositions, it is known that only lightweight, fragile molded parts, and in some cases only molded parts that are not cohesive, or parts that foam markedly out of the mold can now be produced.
Surprisingly, it has now been discovered that most of these prejudices are unjustified, as long as certain factors, described in further detail below, are taken into account.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a method for producing disposable thin-walled molded articles, which overcomes the above-mentioned disadvantages of the heretofore-known devices and methods of this general type.
With the foregoing and other objects in view there is provided, in accordance with the invention, a method for producing disposable, thin-walled molded articles, which comprises:
providing a multi-part mold, preferably a two-part mold with a lower mold member;
preparing a starch-based baking composition with a starch component selected from the group consisting of starch, starch mixtures, flour, flour mixtures, and starch derivatives; adding water at a proportion of 100 to 360% by weight, relative to the starch component, and a mold release agent;
adding polyvinyl alcohol in quantities of 0.5 to 40% by weight, relative to the starch component, to the baking composition, wherein the polyvinyl alcohol has a degree of polymerization of over 1000;
feeding the starch-based baking composition into the lower mold member; and baking and conditioning the baking composition to an initial moisture content of about 2-4% by weight. Thereafter, the moisture content of the composition if allowed to equilibrate with the moisture in the ambient to a level of about 6-22%, and preferably to a level of about 7-12%. Maintaining the moisture content within these limits is important to the strength characteristics of the products of the invention.
The expression "thin-walled material" as used herein is intended to mean that the thickness of the material from which the article of manufacture is shaped is at least about one to two orders of magnitude less that the size of the article itself. For example, the drinking cups, plates, fast-food packages, etc. contemplated herein typically have a wall thickness on the order of about 0.5-3 mm as compared to an overall dimension of the article on the order of about 50-300 mm.
Products with improved flexibility, increased water resistance and better compatibility and hence adhesion for hydrophobic cover layers are obtained if polyvinyl alcohol in quantities of 0.5 to 40% by weight, relative to starch mass, is added to the baking mixture, if the polyvinyl alcohol has a degree of polymerization of over 1000, preferably over 1600 and in particular over 2000, and if the proportion of water is 100 to 360% by weight, relative to starch products.
The products produced by the method of the invention have the following features of interest, particularly with a view to process technology:
1. After baking, the products do not adhere to the baking molds, even though polyvinyl alcohol is a known hot-melt adhesive and softens above its glass transition temperature of about 80° C. This might be ascribed to the fact that polyvinyl alcohol, on heating and drying at high temperatures (below the melting point, which depending on the type, is between 185 and 230° C.), crystallizes rapidly.
X-ray diffraction analyses for molded articles of pure starch exhibit an amorphous diffraction pattern, while in the presence of polyvinyl alcohol, crystalline structures are found.
This crystallinity is also a kind of physical cross-linking, by which the absorption of water and the attendant structural softening are reduced.
In contrast, extruded starch and polyvinyl alcohol foams exhibit less crystallinity, since there is no opportunity for agglomeration in the production process.
2. The "baked" starch and polyvinyl alcohol foams remain partly phase-separate. Electron micrographs of the surface of such molded articles show swollen starch grains embedded in a polyvinyl alcohol matrix, while the interior instead looks homogeneous. The mixture remains phase-separate, since in contrast to extrusion no mixing action or only slight mixing action ensues during baking, and polyvinyl alcohol and starch are largely incompatible. Polyvinyl alcohol, which is a stronger and more-flexible polymer than starch, is suspected of binding together the swollen starch grains and thus increases the mechanical strength and stability of the molded articles. Extruded starch and polyvinyl alcohol foams, conversely, undergo intensive mixing, which is associated with the dissolution of the starch grain structure.
3. Since the final mold is formed directly during the baking process, cross-linking aids which increase the stability and water resistance can be admixed. This is not possible in the extrusion process, because a highly cross-linked material would not be adequately flowable.
It is advantageous in the process of the invention, before the addition of water, to add from 0.5 to 40% by weight, preferably from 0.5 to 24% by weight, relative to starch product, polyvinyl alcohol in dry form as fine powder to the other powdered ingredients to the baking composition and intimately mixed therewith; the polyvinyl alcohol has a degree of polymerization of over 1000, preferably over 1600 and in particular over 2000. To form a homogeneous suspension, water is added to the dry mixture in a quantity of 100 to 300% by weight, preferably 100 to 240% by weight, relative to starch product.
In another variant of the method of the invention, 0.5 to 40% by weight of polyvinyl alcohol in the form of an aqueous solution, preferably at maximum a 10% solution, is added to the baking composition; the polyvinyl alcohol has a degree of polymerization of over 1000, preferably over 1600 and in particular over 2000; and to form a homogeneous suspension, water is added to the dry mixture in a quantity of 100 to 360% by weight, preferably 100 to 240% by weight, relative to starch product.
Polyvinyl alcohol is produced by the polymerization of vinyl acetate and subsequent partial or complete saponification of the acetate groups.
General formula: ##STR1## n=approximately 200-5500, mostly 300-2500 R=H:>97.5% fully saponified≦95.5 to 70% largely or partially saponified.
Polymers with a low residual acetyl content (down to approximately 2%) are classified as being fully saponified, and grades that are largely saponified (90 to 95%) and partly saponified (87 to 89%) are also commercially available. Individual manufacturers also offer a "super"-hydrolyzed grade, with a degree of saponification near 100%.
Toxicologically, no negative findings have been made. Polyvinyl alcohol is degradable; aqueous solutions should therefore require preservation.
The standard grades of polyvinyl alcohol can be classified by their viscosity (mpas in 4% aqueous solution), which goes along in parallel with the degree of polymerization (DP) and the mean molecular weight (number average) (source: TAPPI J., December 1988):
______________________________________ Molecular weight,Viscosity class mPas, 4% number average______________________________________high 45-70 2400-2600 95,000medium I 25-35 1700-1800 65,000medium II 12-16 900-1000 43,000low 2-7 300-700 28,000______________________________________
In the method of the invention, especially preferably, a fully-hydrolyzed polyvinyl alcohol is used.
It has proved to be advantageous that the suspension formed is left to rest before being applied to the mold, the resting time of the baking composition being preferably at least 30 minutes and preferably 45 to 60 minutes.
In the method of the invention, the following are preferred as the release agent: stearates of magnesium, calcium or aluminum, in a quantity of 0.05 to 20% by weight, relative to starch product, but at least 10%, relative to the concentration of polyvinyl alcohol; polymethyl hydrogen siloxanes in a quantity of 0.025 to 11% by weight, relative to starch product, but at least 5% by weight, referred to the concentration of polyvinyl alcohol; and monostearyl citrate in a quantity of 0.025 to 12% by weight, relative to starch product, but at least 5% by weight, referred to the concentration of polyvinyl alcohol are used, on the condition that at concentrations above 0.5% by weight, an at least partial neutralization is done with basic substances in solution or powder form, such as sodium hydroxide solution, potassium hydroxide solution, ammonia solution, water glass and calcium hydroxide, so that the pH value of the baking compositions does not drop below 5.0 and preferably not below 6.0.
The aforementioned release agents can also be used in arbitrary combination, wherein the total concentration does not drop below the lowest individual concentration and does not exceed the highest individual concentration.
The combination of polymethyl hydrogen siloxanes and monostearyl citrate is highly preferred.
Chemically, the monostearyl citrate (MSC), according to its manufacturers, is a mixture of monostearyl and distearyl citrate esters, which show action as oil-soluble chelating agents. The long fatty acid residues lend them their oil solubility, and the free carboxyl groups lend them the complexing action.
The CAS number is 1337-33-3.; the melting point is 47° C. and the solubility in oils is approximately 1% by weight.
The product used was procured from Reilly Chemicals, Brussels, Belgium, and then ground. The manufacturer is Morflex, Inc., Greensboro, N.C., USA.
21 C.F.R. (Volume 21, Code of Federal Regulations) lists the following FDA-approved uses for stearyl citrates:
GRAS as complexing agents up to 0.15% (§182.685)
Use as plasticizer in packaging materials for foodstuffs (§181.27)
As plasticizer for resin-like and polymer coatings (§175.300)
Components for paper and cardboard in contact with aqueous or fatty foodstuffs (§176.170).
Besides the zirconium compounds recited at the outset, compounds such as calcium hydroxide and calcium sulfate, which by ionic action modify the starch products during the baking process, can also be used for the sake of better cross-linking. As a result of all these provisions, a strengthening of the structure of the baked molded articles is obtained.
With the above-noted and other objects in view, there is also provided, in accordance with the invention, an article of manufacture shaped from a thin-walled material comprising starch and polyvinyl alcohol, wherein the material is characterized by a phase gradient between opposing surfaces of the thin-walled material, such that the starch and polyvinyl alcohol near the surfaces is biphasic with at least some of the starch characterized as substantially intact granules occupying a discontinuous phase and such that substantially all the starch near the center of the material between the surfaces is characterized by at least partially disrupted granules that are more highly interspersed with the polyvinyl alcohol relative to the starch near the surfaces.
In accordance with yet a further feature of the invention, the polyvinyl alcohol is present in an amount of 0.5 to 40% by weight of the starch.
In accordance with yet another feature of the invention, the polyvinyl alcohol and the starch are crosslinked.
In accordance with yet an added feature of the invention, the material comprises a moisture content in the range of about 7-12% by weight.
In accordance with a concomitant feature of the invention the article of manufacture includes an effective amount of a release agent.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is exemplified and described herein as embodied in a method for producing disposable thin-walled molded articles, it is nevertheless not intended to be limited to the examples described, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments and individual recipes.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The figures in the recipes each refer to 100 parts by weight of raw starch material with its natural water content. The solutions of polyvinyl alcohol were prepared while stirring and heating in deionized water (polyvinyl alcohol solution). Powdered raw materials are stirred in premixed form into the liquid ingredient.
The baking temperature is approximately 190° C.
Water absorption test: A molded article equilibrated for 45% relative humidity for seven days is filled with 100 ml of deionized water. After 25 minutes, the water is poured off and the increase in weight is determined in grams.
The mechanical strength tests are performed with an Instron universal testing machine. A pressure cylinder 35 mm in diameter is first moved from above to the molded article, which rests on a metal ring with an inside diameter of 80 mm; then at a feeding speed of 30 mm/min, a load and travel graph is recorded. From this, the load until break, the elongation until break, the deformation work and the modulus of elasticity can be calculated.
__________________________________________________________________________Recipe No. 1 2 3 4 5 6__________________________________________________________________________Bakingmold: cupStarch(1) 100 100 100 100 100 100PVAL -- 9.5(4) 10(4) 9.5(4) 10(5) 10.5(6)solidRelease 2 1.9 2 1.9 2 2.1agent(2)Thickening 0.6 0.6 0.6 0.3 0.6 0.3agent(3)Water 100 114 110 114 110 126Release -- -- -- -- -- --agentViscosity 0.7 2.5 2.3 0.7 7.0 1.9after60 min.Baking 50 45 50 50 50 45time (sec)Baking 180 180 180 180 180 180temp.(° C.)Weight (g) 4.2 7.2 7.2 6.5 5.7 5.1Brittleness yes red. red. Red. red. red.Adhesion no yes yes yes case- no wiseBaking no yes yes yes no noresiduesDiscolor- no yes yes yes no noationComments compar- unsuit- unsuit unsuit deterio- ison ableableable rated__________________________________________________________________________ (1)Potato starch (2)Magnesium stearate (3)Guar (4)Poval B05, Denka, Japan, low molecular DP approximately 550, partly hydrolyzed (5)Poval B24, Denka, Japan, high molecular DP approximately 1700, partly hydrolyzed (6)Poval K17L, Denka, Japan, high molecular DP approximately 2400, fully hydrolyzed
______________________________________Recipe No. 7 8 9 10 11 12______________________________________Baking mold: cupStarch(1) 100 100 100 100 100 100PVAL solid(4) -- 0.5 2 5 10 20Release agent(2) 2 2 2 2 3 4Thickening agent(3) 0.3 0.3 0.3 0.3 0.3 0.3Water 100 100 103 107 115 132Viscosity after 60minutesBaking time (sec) 50 50 45 45 45 45Baking temp. (° C.) 180 180 180 180 180 180Weight (g) 4.3 4.5 4.7 5.0 5.2 5.1Brittleness yes +/- red. red. red. red.Adhesion no no no no no noBaking residues no no no no no noDiscoloration no no no no no noComments comparison (5)______________________________________ (1)Potato starch (2)Magnesium stearate (3)Guar (4)Poval K17L, Denka, Japan, high molecular DP approximately 2400, fully hydrolyzed (5)Brittleness reduced slightly
__________________________________________________________________________Recipe No. 13 14 15 16 17 18__________________________________________________________________________Baking mold:plateStarch(1) 100 100 100 100 100 100PVAL solution 10% -- 25(4) 25(4) 50(4) 100(4) 50(5)Release agent(2) 1.8 1.8 1.8 1.9 2.1 2Thickening 0.5 0.6 -- -- -- --agent(3)Water 100 75 75 50 6.7 110Filler(6) -- -- -- -- -- 10Baking time (sec) 120 120 145 120 130 140Baking temp. (° C.) 200 200 200 200 200 200Weight (g) 14 14.5 16 17 17.5 22Brittleness yes red. red. red. red. red.Adhesion no no no no no partlyBaking residues no no no no no yesDiscoloration no no no no no noComments compar- dete- ison rio- rated__________________________________________________________________________ (1)Potato starch (2)Magnesium stearate (3)Guar (4)Airvol 525, Air Products, USA, >98% hydrolyzed, DP approximately 1600 (5)Mowiol 10-98, Hoechst, Germany, >98% hydrolyzed, DP approximately 1000 (6)SEStandard, Naintsch, Austria
______________________________________Recipe No. 19 20 21 22 23______________________________________Baking mold:plateStarch(1) 100 100 100 100 100PVAL solution -- 25(4) 50(4) 100(4) 217(5)10% W/WRelease 1.8 1.8 1.8 1.8 2.17agent(2)Thickening 0.55 0.25 -- -- --agent(3)Water 103 75 55 0 --Sodium -- -- 1 1 1.1hydroxide40 g/lBaking time 130 115 105 115 100(sec)Baking temp. 200 200 200 200 200(° C.)Weight (g) 23.5 22.5 20 18.5 12Brittleness yes red. red. red. red.Adhesion no no no no partlyBaking no no no no noresiduesDiscoloration no no no no noComments compari deterio- son rated______________________________________ (1)Cornstarch (2)Magnesium stearate (3)Guar (4)Airvol 325, Air Products, USA; 98% hydrolyzed, DP approximately 1600 (5)Airvol 350, Air Products, USA; 98% hydrolyzed, DP approximately 2400
______________________________________Recipe No. 24 25 26 27 28______________________________________Bakingmold: plateStarch(1) 100 100 100 100 100PVAL 217(4) 97(4) 50(5) 100(5) 217(5)solution10% W/WRelease 2.17 1.93 1.8 1.8 2.17agent(2)Thickening -- -- -- -- --agent(3)Water 43.5 48.5 50 20 --Sodium 1.1 1 1 1 1.1hydroxide40 g/lViscosity 600 600 800 500 130after 60minutesBaking time 90 100 120 110 115(sec)Baking 200 200 180 180 180temp.(° C.)Weight (g) 9.5 15 21 19 12Brittleness red. red. red. red. red.Adhesion no no no partly yesBaking no no yes yes yesresiduesDiscolor- no no no no noationComments deterio- deterio- deterio- rated rated rated______________________________________ (1)Cornstarch (2)Magnesium stearate (3)Guar (4)Airvol 350, Air Products, USA; 98% hydrolyzed, DP approximately 2400 (5)Airvol 523, Air Products, USA; 88% hydrolyzed, DP approxinately 1600
______________________________________Recipe No. 29 30 31______________________________________Baking mold: plateStarch(1) 100 100 100PVAL solution 10% W/W 50(4) 100(4) 100(4)Release agent(2) 1.8 1.8 2.0Thickening -- -- --agent(3)Water 50 20 --Baking time(sec) 120 120 115Baking temperature (° C.) 200 200 180Weight (g) 16.5 16 12Brittleness red. red. red.Adhesion partly partly partlyBaking residues yes yes yesDiscoloration no no noComments deterio- deterio- deterio- rated rated rated______________________________________ (1)Potato starch (2)Magnesium stearate (3)Guar (4)Airvol 523, Air Products, USA; 88% hydrolyzed, DP >2400
______________________________________Recipe No. 32 33 34 35 36______________________________________Bakingmold: fast-food shellwith hingeStarch(1) 100 100 100 100 100PVAL -- 210(5) 158(5) 105(5) 105(5)solution 10%W/WRelease 1.8 3.4 3.4 3 3agent(2)Thickening 0.5 -- -- -- --agent(3)Fibrous -- -- 2 4 6material(4)Water 100 -- 25 65 75Weight (g) 21.3 19.2 18.9 18.6 18.0Brittleness yes red. red. red. red.Adhesion no partly no no noBaking no no no no noresiduesDiscolor- no no no no noationComments compar- hinge hinge hinge hinge ison; works works works works hinge breaks______________________________________ (1)Potato starch (2)Magnesium stearate (3)Guar (4)Cellulose fiber (5)Mowiol 66-100, Hoechst, "superhydrolyzed, high molecular
__________________________________________________________________________Recipe No. 37 38 39 40 41 42__________________________________________________________________________Baking mold:cupStarch(1) 100 100 100 100 100 100PVAL powder 10(4) 10(4) 7(5) -- -- 10(4)PVAL solution -- -- -- 110(6) 110(6) --10%Release 3 3 3 3 3 3agent(2)Thickening -- -- 0.6 -- -- --agent(3)Glycerin, 87% -- 5 -- -- 5 --Wheat fiber -- -- -- -- -- 5Water 115 115 115 32 32 158Weight (g) 5.7 6.8 6.3 4.9 -- 4.9Baking time 40 45 32 40 45 35(sec)Brittleness red. red. Red. red. red. red.Adhesion no no partly no no noBaking no no no partly partly noresiduesDiscoloration no no no no no noComments more poor flexible unmolding than 38!__________________________________________________________________________ (1)Potato starch (2)Magnesium stearate (3)Guar (4)Airvol 523S, Air Products, USA; 88% hydrolyzed, DP approximately 1600 (5)Poval K17, Denka, Japan, high molecular, fully hydrolyzed (6)Fluka, molecular weight 72,000, fully hydrolyzed
______________________________________Recipe No. 43 44 45 46 47______________________________________Bakingmold: cupStarch(1) 100 100 100 100 100PVAL 15(4) 15(5) 15(6) 5(4) 5(4)powderRelease 3 3 3 3 3agent(2)Thickening -- -- -- 0.3 0.3agent(3)Filler(7) -- -- -- -- 3Water 160 126 130 100 108Weight (g) 4.9 4.9 4.9 4.2 4.1Brittleness red. red. red. red. Red.Adhesion no no no no noBaking partly slight no partly partlyresiduesDiscolor- no no no no noationComments deterio- deterio- deterio- deterio- rated rated rated rated______________________________________ (1)Potato starch (2)Magnesium stearate (3)Guar (4)Airvol 523S, Air Products, USA; 88% hydrolyzed, DP approximately 1600 (5)Fluka, PVAL, molecular weight 100,000, 86-89% hydrolyzed (6)Fluka, PVAL, molecular weight 72,000, 97.5-99.5% hydrolyzed (7)Ulmer Weiβ HMH
______________________________________Recipe No. 48 49 50 51 52______________________________________Bakingmold:fast-foodshell withhingeStarch(1) 100 100 100 100 100PVAL 8(5) 21(6) 15(6) 10(6) 10(7)Release 3 3.5 3 3 3agent(2)Thickening 0.1 -- -- 0.3 0.3agent(3)Fibrous -- -- 5 5 3material(4)Water 125 185 150 135 115Brittleness red. red. red. red. red.Adhesion no no no no noBaking no no no no noresiduesDiscolor- no no no no noationComments hinge hinge hinge hinge hinge works works works works works______________________________________ (1)Potato starch (2)Magnesium stearate (3)Guar (4)Cellulose fiber (5)Fluka, PVAL, molecular weight 72,000, fully hydrolyzed (6)Mowiol 66-100, Hoechst, "superhydrolyzed, high molecular, ground (7)Airvol 523S, Air Products, USA; 88% hydrolyzed, DP approximately 1600
______________________________________Recipe No. 53 54 55 56 57______________________________________Bakingmold: cupStarch(1) 100 100 100 100 100PVAL 7(5) 10(6) 10(7) 10(7) 10(7)powderRelease 3 3 3 3 3agent(2)Thickening 0.6 -- -- -- --agent(3)Wheat -- -- -- 4 6fiber(4)Water 11 125 130 145 150Weight (g) 5.7 5.2 4.9 4.6 4.5Baking 40 40 40 40 40time (sec)Brittleness red. red. red. red. Red.Adhesion no no no no noBaking no no no no noresiduesDiscolor- no no no no noation______________________________________ (1)Potato starch/Biolys 3/1 Biolys = modified starch, Lyckeby Starkelsen, Sweden (2)Magnesium stearate (3)Guar (4)Vitacel WF 600, Rettenmaier, Germany (5)Poval K17, Denka, Japan, DP approximately 1700, fully hydrolyzed (6)Airvol 165, Air Products, "superhydrolyzed, high molecular, ground (7)Airvol 523S, Air Products, USA; 88% hydrolyzed, DP approximately 1600
______________________________________Recipe No. 58 59 60 61 62 63______________________________________Baking mold: 1 2 3 4 5 10platePotato starch 100 100 100 100 100 100PVAL solution, 0 0 89.7 89.7 201.7 377.610%,(1)Release 1.8 1.8 2 2 2.4 4agent(2)Thickening 0.5 0.7 0 0 0 0agent(3)Water 100 143 44.8 78.9 0 0Viscosity, Pa/s 6.5 1.5 35 4.5 45 58Weight (g) 16.3 11.4 13.7 10.8 10.4 10.5Baking time 130 120 130 115 130 95(sec)Water -- 13 10.6 8.7 8 10.5absorptionAdhesion no no no partly no noBaking residues no no no yes no noDiscoloration no no no no no no______________________________________ (1)Airvol 350, >98% hydrolyzed, DP approximately 2400 (2)Magnesium stearate (3)Guar
______________________________________Load until break, N; 97 77 148 95 120 11645% rFLoad per g of weight 6 6.8 10.8 8.8 11.5 11Relative to recipe No. 100 114 182 148 184 18658Elongation to break; 5.1 6.2 7.7 8.3 13.4 11.445% rFRelative to recipe No. 100 122 151 163 263 22458______________________________________
__________________________________________________________________________ Recipe No. 64 65 66 67 68 69__________________________________________________________________________Baking mold: plate 25 26 27 33 35 38Potato starch 100PVAL solution, 10% 89.7(1) 93.8(1) 201.7(1) 89.7(2) 201.7(2) 205.5(3)Release agent(4) 2.1Water 26.9 82.6 0Viscosity, Pa/s 9Weight (g) 17.3 11.1 13.1 15.6 12.4 12.6Baking time (sec) 130Water absorption 10.2 18.4 16.8 18.5Adhesion no yes no no no noBaking residues noDiscoloration no__________________________________________________________________________ (1)Airvol 325, >98% hydrolyzed, DP approximately 1600 (2)Airvol 540, 88% hydrolyzed, DP approximately 2000 (3)Airvol 523, 88% hydrolyzed, DP approximately 1600 (4)Magnesium stearate
______________________________________Load until break, N; 45% rF 210 88 150 139 126 149Load per g of weight 12.1 7.9 11.8Relative to recipe No. 58 203 133 198Elongation to break; 45% rF 8.1 6.3 8.7Relative to recipe No. 58 159 124 171______________________________________
______________________________________ Recipe No. 70 71 72 73 74______________________________________Baking mold: plate 40 41 42 48 49Cornstarch 100 100 100 100(2) 100(2)PVAL solution, 10%,(1) 0 98.9 222 205Release agent(3) 2.6 2.6 3.6 2.4Thickening agent(4) 1.6 0Water 185.7 98.9 11.1 5.7Viscosity, Pa/s 9.8 56Weight (g) 16 14.5 13.7 8.5Baking time (sec) 115 120 110 80Water absorption 12 12.8 10.4 -- 7.5Adhesion no yes no noBaking residues no yes noDiscoloration no no no______________________________________ (1)Airvol 350, >98% hydrolyzed, DP approximately 2400 (2)Wax cornstarch (3)Magnesium stearate (4)Guar
______________________________________Load until break, N; 45% rF 88 81 106 32 70Load per g of weight 5.5 5.6 8.2Relative to recipe No. 58 92 94 138Elongation to break; 45% rF 3.8 6.7Relative to recipe No. 58 75 98 131______________________________________
______________________________________ Recipe No. 75 76 77 78 79______________________________________Baking mold: plate 43 44 45 46 47Cornstarch 100 100 100PVAL solution, 10% 0 0 222(1) 223(1) 223(2)Release agent(3) 2.4 2.4 3Thickening agent(4) 1.6 1.6 0Water 173.3 173.3 11.3Calcium hydroxide, 0.22 0.88 0.27powderedHydrogen peroxide, 30% 0 0 3.56Viscosity, Pa/s 12 13 8.5Weight (g) 15.3 15.1 10.7Baking time (sec) 120 120 85Water absorption 9.7 8 13Adhesion no no noBaking residues no yes noDiscoloration no no no______________________________________ (1)Airvol 350, >98% hydrolyzed, DP approximately 2400 (2)Airvol 325, >98% hydrolyzed, DP approximately 1600 (3)Magnesium stearate (4)Guar
______________________________________Load until break, N; 45% rF 95 75 106 73 68Load per g of weight 6.2 6.4Relative to recipe No. 58 104 83 107Elongation to break; 45% rF 4.4 3.7 5.5Relative to recipe No. 58 86 73 108______________________________________
______________________________________Recipe No. 80 81 82 83 84 85______________________________________Baking mold: plate 17 18 19 20 21 22Potato starch 100 100 100 100 100 100PVAL solution, 10%(1) 0 211 211 0 211 0Release agent(2) 2.1 2.2 0 2.2 2.2 2.2Thickening agent(3) 1.5 0 0 1.5 0 0Water 152 0 0 152 0 152Calcium hydroxide, 0.42 0.51 0.51 0 0 0powderedCalcium sulfate, 0 0 0 0.43 0.51 0powderedCross-linking 0 0 0 0 0 1.27*agent(4)Viscosity, Pa/s -- 120 170 7.4 120 --Weight (g) 17.8 13.6 16.4 11.4 10 23.6Baking time (sec) 160 150 135 130 130 175Water absorption 11 4.4 6.6 10.6 6.1 13.4Adhesion no no yes no no noBaking residues yes yes yes no no yesDiscoloration no no no no no no______________________________________ (1)Airvol 350, >98% hydrolyzed, DP approximately 2400 (2)Magnesium stearate (3)Guar (4)Ammonium zirconium carbonate (Bacote 20) *Adjustment of pH to 9.5 with 1N KOH before the addition
______________________________________Load until break, N; 88 172 170 65 129 11645% rFLoad per g of weight 4.9 12.6 10.4 5.7 12.9 4.9Relative to recipe No. 83 213 174 96 217 8358Elongation to break; 4.5 7.8 -- 5.1 7.8 545% rFRelative to recipe No. 58 88 153 -- 100 153 98______________________________________
__________________________________________________________________________ Recipe No. 86 87 88 89 90__________________________________________________________________________Baking mold: plate 23 24 28 29 30Potato starch 100PVAL solution, 10% 215(1) 215(1) .sup. 223(2) 223(2) 222(2)Release agent(3) 1.9Water 0Cross-linking agent 3.17(5)#Viscosity, Pa/s 31Weight (g) 17.1Baking time (sec) 130Water absorption 3.9Adhesion noBaking residues noDiscoloration no__________________________________________________________________________ (1)Airvol 350, >98% hydrolyzed, DP approximately 2400 (2)Airvol 325, >98% hydrolyzed, DP approximately 1600 (3)Magnesium stearate (4)Ammonium zirconium carbonate (Bacote 20) *Adjustment of pH to 9.5 with 1N KOH before addition **Adjustment of pH to 9.4 with 1M ammonia before addition (5)Zirconium acetate solution (22% ZrO2) #Adjustment of pH to 4.7 with 1N acetic acid before addition
______________________________________Load until break, N; 45% rF 113 267 204 158 174Load per g of weight 7.4 12.8 10.9 10.2Relative to recipe No. 58 124 216 171Elongation to break; 45% rF 3.7 8.4 5.2Relative to recipe No. 58 73 165 102______________________________________
______________________________________Recipe No.91 92 93 94 95______________________________________Baking 7 8 31 32 666mold:platePotato 100starchPVAL 221(1) 220(1) 225(2) 221(2) 0solution,10%Release 2.2(3) 2.2(4) 1(3) + 1(4)agentThick- 0.5eningagent(5)Water 110Viscosity, 39Pa/sWeight (g) 18Baking 100time (sec)Water -- 5.9absorptionAdhesion noBaking noresiduesDis- nocoloration______________________________________ (1)Airvol 350, >98% hydrolyzed, DP approximately 2400 (2)Airvol 325, >98% hydrolyzed, DP approximately 1600 (3)Magnesium stearate (4)Monostearyl citrate (5)Xanthan
______________________________________Load until break, N; 45% rF 64 81 200 146 --Load per g of weight 8.8 9 --Relative to recipe No. 58 147 151 --Elongation to break; 45% rF 7.5 7.2 --Relative to recipe No. 58 147 141 --______________________________________
______________________________________Recipe No.96 97 98 99 100 101______________________________________Baking 65.1 .2 .3 .4 .5 .6mold:platePotato 100 100 100 100starchPVAL 0 0 10powder(1)Release 2 2 3agent(2)Release 0 0 1agent(3)Thick- 0.6(4) 0.6(4) 0.5(5) 0.5(5)eningagentHydrogen 0 0 4peroxide,30%Calcium 0 0.5 0hydroxide,powderedWater 110 110 130 130Viscosity, 1.1 1.4 4.5 4.5Pa/sWeight (g) 17.5 23.4 19.6 17.1 17.1 14.1Baking 100 130 90time (sec)Adhesion no no no no no noBaking no no noresiduesDis- no slight nocoloration______________________________________ (1)Airvol 523, 88% hydrolyzed, DP approximately 1600 (2)Magnesium stearate (3)Polymethyl hydrogen siloxane NM203 (4)Guar (5)Xanthan
__________________________________________________________________________Recipe No. 102 103 104 105 106 107 108 109__________________________________________________________________________Baking mold:plateStarch 100(1) 100(1) 100(2) 100(2) 100(3) 100(3) 100(4) 100(4)PVAL sol., 0 203(5) 0 223(5) 0 205(6) 0 222(6)10% in waterRelease 1.6 2 2 2.4 2 2.4 2 3.6agent(7)Thickening 0.8 0 1 0 1 0 1 0agent(8)Water* 142 0 159 1.6 148 5.7 171 11.1Weight, (g), 8.7 8.2 11.2 13 7.4 8.5 14 13.750% rH**Baking time 85 85 110 120 75 80 110 110(sec)Baking temp. 200 200 200 200 205 205 205 205(° C.)Adhesion no no no no no no no noBaking no no no no no no no noresiduesDiscoloration no no no no no no no noLoad until 18 51 38 49 14 35 42 70break (N),20% rH**Elongation to 2.9 6.8 2.9 3.9 2.4 4 2.4 2.5break (mm),20% rH**Load until 46 74 70 141 26 66 72 106break (N),50% rh**Elongation 6.6 11.5 6.3 9.1 5.2 6.6 4 5.6tobreak (mm), 50% rh**Load per g 5.3 9 6.3 10.8 3.5 7.8 5.1 7.7of weight,50%**__________________________________________________________________________ *33% total solids **after 7 days equilibration (1)Potato amylopectin (Lyckeby Starkelsen, S) (2)Potato starch (Avebe, NL) (3)Waxy maize starch (Amioca, National Starch) (4)Corn starch (Buffalo 3401, CPC International, USA) (5)Airvol 325, >98% hydrolyzed, DP approximately 1600 (6)Airvol 350, >98% hydrolyzed, DP approximately 2400 (7)Magnesium stearate (8)Guar gum
__________________________________________________________________________Recipe No. 110 111 112 113 114 115 116 117__________________________________________________________________________Baking mold:plateStarch 100(1) 100(2) 100(2) 100(2) 100(2) 100(2) 100(3) 100(3)PVAL solution, 0 0) 101(4) 0 169(4) 225(4) 0 230(5)10% in waterRelease agent 2 1.8 4.1 2 4.3 4.5 2 2(6)Thickening 1 0.6 0 1 0 0 1 0agent(7)Water 167 135 17.4 146 19.2 0 167 7.6% solids 33 39 46 37 37 34 33 33Weight (g),50% rH 27.3 25.3 33.4 20 18.1 16.5 10.7 10.5**Baking time 180 110 110 95 90 110 80 80(sec)Baking temp. 205 200 210 205 210 210 205 205(° C.)Product irregu- smooth smooth smooth smooth irregu- smooth smoothappearance lar larAdhesion no no no no no no no noBaking residues no no no no no no no noDiscoloration no no no no no no no noLoad until 76 134 54 101 65 34 54break (N),20% rH**Elongation to 2.1 2.6 2.7 3.7 4.4 2.7 3.4break(mm),20% rH**Load until break, 125 292 126 161 148 59 86(N), 50% rH**Elongation to 2.9 7.8 5.9 8.1 10.6 6.9 8.1break(mm),50% rH**Load per g of 4.9 8.7 6.3 8.9 9 5.5 8.2weight, 50%**__________________________________________________________________________ **after 7 days equilibration (1)50%amylose corn starch (Amaizo 5, American Maize, USA) (2)50%amylose corn starch derivate (Amaizo Crisp Tex, American Maize, USA (3)Corn starch derivate (Ethylex 2095, A.E. Staley, USA) (4)Airvol 350, >98% hydrolyzed, DP approximately 2400 (5)Airvol 523, >88% hydrolyzed, DP approximately 1600 (6)Magnesium stearate (7)Guar gum
______________________________________ Recipe No. 118 119______________________________________Baking mold: plateStarch(1) 100PVAL solution, 15% in water 254(3) 254(3)Release agent(4) 2.6 2.6Water 21% PVAL relative to starch 38% solids in batter 33Weight (g), 50% rH** 14.2Baking time (sec) 125Baking temp. (° C.) 200Adhesion no slightBaking residues slightDiscoloration noLoad until break (N), 20% rH** 73 117Elongation to break (mm), 20% rH** 5.1Load until break (N), 50% rH** 156Elongation to break (mm), 50% rH** 9.4Load per g of weight, 50% rH** 11.0______________________________________ (1)Potato Starch (Avebe, NL) (2)Airvol 325, >98% hydrolysed, DP approximately 1600 (3)Airvol 523, >88% hydrolysed, DP approximately 1600 **after 7 days equilibration
______________________________________ Recipe No. 120 121 122 123 124______________________________________Baking mold: plateStarch(1) 100 100PVAL-solution, 10% 203(2) 205(3) 205(3)in waterRelease agent(4) 1.6 2.0 2.0 2.1Thickening agent(5) 0.8 0Aspen fiber(6) 5Water 142 16% solids 33Tray weight (7 days, 8.7 7.950% rH)Baking time (sec) 80Adhesion no no no noBaking residues noDiscoloration noLoad until break (N), 18 51 22 5920% rHElongation to break 2.9 7.3(mm) 20% rHLoad until break (N), 5650% rHElongation to break 6.6 7.3(mm) 50% rHLoad until break (N), 3780% rHElongation to break 11.4(mm) 50% rHLoad until break (N), 2985% rHElongation to break 5.0 8.0(mm) 85% rHLoad per g of weight 5.3 7.150% rH______________________________________ (1)Potato amylopectin (Lyckeby Starkelsen, S) (2)Airvol 325, >98% hydrolyzed, DP approximately 1600 (3)Airvol 350, >98% hydrolyzed, DP approximately 2400 (4)Magnesium stearate (5)Guar gum (6)Supplier: Super Wood Corp., Phillipps, WI
______________________________________ Recipe No. 125 126 127 128 129 130______________________________________Baking mold: platestarch(1) 100 100 100PVAL, powder(2) 7.5 10PVAL solution, 10% in 82.5water(3)Release agent(4) 0Release agent(5) 0.75 1.0 0.9Water 110 110 110plate weight, 50% rH 17.2 17.7 17.4 16.9conditionedBaking time (sec) 110 110 110Adhesion no no no no no noBaking residues no noDiscoloration no no______________________________________ (1)Potato starch (Agrana, A) (2)Airvol 523S, 88% hydrolyzed, DP approximately 1600 (3)Airvol 350, >98% hydrolyzed, DP approximately 2400 (4)Magnesium stearate (5)Polymethylhydrogensiloxane, Dow Corning 1107 fluid
______________________________________Recipe No. 131 132 133 134 135 136______________________________________Baking mold: platePotato starch (1a) 100 100 100 100 100Wheat starch (1b) 100Waxy potato 100 100starch(1c)PVAL, powder(2) 16.7 16.7 10 10PVAL-solution, 10% 0 100in water(3)Release agent(4) 5.0 5.0 3.0 2.0 2.0 2.0Release agent(5) 0 0 0 0 0 1.0Thickening 0.83 0.83 0.5 1.0 0.5 0agent(6)Aspen fiber(7) 0 0 5 0 0 0Mineral filler(8) 66.7 66.7 0 0 0 0Wax powder(9) 0 8.3 0 0 0 0Water 216.7 216.7 210 260 114 30plate weight, 18.0 22.0 10.0 7.7 8.4 8.0after bakingBaking time (sec.) 60 60 70 70 50 60Adhesion no slight no no no noBaking residues slight slight no no no noDiscoloration no no no no no noLoad until break 43 55(N), 40% rHElongation to 2.7 2.8break (mm) 40% rHLoad until break 48 50 46 43 41 68(N), 55% rHElongation to 3.6 3.9 5.8 5.5 4.4 6.3break (mm) 55% rH______________________________________ (1a)Potato starch (Agrana, A) (1b)Wheaten corn starch (Starch Australasia, Australia) (1c)Potato amylopectin (Lyckeby Starjeksebm S) (2)Airvol 523S, 88% hydrolyzed, DP approximately 1600 (3)Airvol 350, >98% hydrolyzed, DP approximately 2400 (4)Magnesium stearate (5)Polymethyldrogensiloxane, Dow Corning 1107 fluid (6)Guar gum (7)Supplier: Super Wood Corp., Philipps, WI (8)Special Extender Naintsch BC60, (Luzenac Naintsch, A) (9)Hoechst Wachs OP Puler fein, (Hoechst, Germany)
The significant change in baking performance when powdered polyvinyl alcohol is used was especially surprising. It contributes both to shortening of the baking times and to an increase in weight and in the stability of the molded articles, even though because of an increase in viscosity when the polyvinyl alcohol powder is added, the amount of water in the recipe must be increased. A combination of adding powdered polyvinyl alcohol with inorganic fillers or organic fibrous materials in powdered form is especially advantageous.
This must be a specific unexpected property of polyvinyl alcohol, since other hydrophilic polymers, such as various hydrocolloids, with a similarly viscosity-increasing effect, do not exhibit this property. It can only be suspected that this has to do with the low compatibility between polyvinyl alcohol and starch (see "Mowiol Polyvinylalkohol" [Mowiol polyvinyl alcohol], company publication by Hoechst AG, 1984), or with the only-partial solubilization of the polyvinyl alcohol. On the microscopic level, this could lead to reduced pore growth in the baking process and thus to greater density of the molded articles, but it simultaneously makes the escape of steam easier and thus reduces the baking time relative to the proportion of water.
Electron micrographs show a higher-viscosity flow in the baking mold or better cohesion at the surface of the molded article, which is demonstrated also by the reduction in visible microscopic pores.
Another surprising observation (recipes 38 and 41) is that the addition of glycerin, which is a known plasticizer for polyvinyl alcohol, does not further increase the flexibility of the molded articles, measured by bend stress testing. In fact, a reduction was observed, although this could also be ascribed to the worsening of the baking performance (steaming out). Thus in example 41, for instance, there were also unmolding problems, and the baking time was increased.
The use of polyvinyl alcohol improves the mechanical properties of the molded articles, especially when there is a change in humidity, as shown by the following comparison:
Each 4 to 5 specimens are equilibrated at room temperature for one day at various relative humidities. Then by texture measurement, the breaking load (Fm), the deformation travel (Lm) and the work in joules (Wm) expended for the purpose are determined.
______________________________________Recipe No. % rF Weight, g Fm (N) Lm (mm) Wm (J)______________________________________13 22 15.5 74 3.0 0.11 50 15.2 95 4.2 0.21 80 15.7 98 6.3 0.3531 22 12.5 126 4.2 0.31 50 12.1 149 5.8 0.48 80 12.9 111 6.7 0.43______________________________________
Example 13 (reference without polyvinyl alcohol) shows the following:
1. Despite increased weight, a reduced breaking load Fm and deformability to break Lm.
2. The work Wm to be expended for the deformation to break exhibits a significant rise, especially for low humidity.
These data indicate a greater flexibility of the molded articles.
Forming a flexible hinge as a connection between two mold halves has thus far been an unsolved problem in the production of starch-based molded articles. Admittedly, via a higher moisture absorption in conditioning, for instance at 75% relative humidity, the comparison recipes (No. 32 and 37) are also flexible enough that an unmolded hinge can be actuated repeatedly by opening and closing without breaking. Nevertheless, even at medium humidities around 40 to 60%, the vulnerability to breakage is so high that reliable function of such a hinge no longer exists.
Recipes No. 33-36 and 38-42, however, exhibit reliable function: actuation at least ten times at 50% relative humidity.
Examples 58, 59: comparison examples without polyvinyl alcohol; they have high water absorption, lesser breaking load and stretchability.
Examples 60-63: the use of polyvinyl alcohol increases the breaking load and the stretchability.
The more highly diluted recipe 61 produces very lightweight molded articles, along with a tendency to adhesion and a slight formation of residues on the baking molds. A remedy is provided here by a more-effective release agent (see recipe 92). As recipes 62 and 63 show, it is also possible to use higher doses of polyvinyl alcohol (about 38% polyvinyl alcohol to starch in 63), but without producing marked improvements in mechanical performance.
Examples 64-69, with various types of high- and medium-molecular polyvinyl alcohol, show positive effects on the breaking load and the stretching performance. From example 65, the effect of great dilution or low viscosity on the adhesive action of baking compositions that contain polyvinyl alcohol is again apparent.
Examples 70-74: 70 and 73 are comparison examples with cornstarch and wax cornstarch, respectively. The mechanical parameters are somewhat below those of molded articles of potato starch, but they are also improved by polyvinyl alcohol. In example 71, a certain adhesive effect of low-viscosity recipes can again be seen.
Examples 75-84: The use of Ca(OH) 2 in recipes 75-82 produces comparatively denser, heavier and hence more-solid molded articles, but conversely the stretchability is slightly reduced. Using polyvinyl alcohol jointly together with Ca(OH) 2 reduces the water absorption here significantly (recipes 77, 78, 81, 82). Ca(SO 4 ) also shows this influence (see recipes 80, 83 and 84). The baking residues formed by calcium hydroxide are unproblematic from a baking standpoint; no adhesion; no buildup of thicker layers.
Examples 85-90: Cross-linking reagents based on zirconium salt increase the product weight and the breaking load; together with polyvinyl alcohol, the water absorption is also especially effectively reduced.
Examples 91-95: Example 91, as a comparison example, exhibits the aforementioned adhesion problem in low-viscosity, more heavily diluted baking compositions, which can be avoided by monostearyl citrate.
Examples 96-101: Use of polyvinyl alcohol powder; comparison examples with and without Ca(OH) 2 .
Examples 102-109: Note the excellent elongation of potato amylopectin/PVOH plates at 20% humidity (#103) and also the good elongation of waxy maize/PVOH plates (#107). This is surprising since it is known in the art that the flexibility of extruded foams made from pure starch decreases as amylopectin content increases. In the present examples, it is hypothesized that PVOH occupies the continuous phase, thus leading to higher elongation to break.
Examples 110-117: As shown by recipe No. 110, regular high amylose corn is not suitable. For high amylose corn starch derivates, a minimum solids content over 35% is recommended.
Examples 118-119: Plates can be made from mixtures of starch and 15% polyvinyl alcohol even though such batters are very viscous.
Examples 120-124: In amylopectin starches (see also example 102-109) compared to regular starches we see higher strength increase, when PVAL is added, especially at low and high humidities. We assume, because here is no amylose to leach into the PVAL phase and make it less strong and flexible. Therefore the influence of fibers in example 124 is not as large as in former examples, e.g. of corn starch-fiber combinations.
Examples 125-130: Some examples with PVAL powder or solution together with different release agent or their combination.
Examples 131-136: Some more examples, 131 and 132 with higher concentration of inorganic fillers. Due to the additon of PVAL these still show acceptable mechanical properties.
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Disposable, thin-walled molded articles, such as cups, plates, fast-food packages, trays, flat sheets and the like are produced by applying a starch-based baking composition onto the lower mold part of a multi-part, preferably two-part mold, and by baking and conditioning the composition to a moisture content of between 6 and 22% by weight. The baking composition, in addition to water and a starch or starch mixtures and/or flour or flour mixtures and/or starch derivatives, contains a fat-free or oil-free release agent and, optionally, other typical additives. Polyvinyl alcohol is added to the baking mixture in quantities of 0.5 to 40% by weight, relative to the starch component. The polyvinyl alcohol has a degree of polymerization of over 1000, preferably over 1600 and in particular over 2000, and the proportion of water is 100 to 360% by weight, relative to the starch component. Polyvinyl alcohol can be added either in dry form or in the form of an aqueous solution.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of International Application No. PCT/KR2014/000177 filed on Jan. 8, 2014, which claims priority to Korean Application No. 10-2013-0020591 filed on Feb. 26, 2013. The applications are incorporated herein by reference.
TECHNICAL FIELD
[0002] The present invention relates to a combustion apparatus having an intake air/exhaust air heat exchanger, and more particularly, to a combustion apparatus having an intake air/exhaust air heat exchanger, in which heat exchange is performed between exhaust gas generated from a burner and exhausted to the outside and intake air flowing from the outside.
BACKGROUND ART
[0003] In general, a combustion apparatus is to heat water using combustion heat that is generated in a combustion process of fuel and circulate the heated water along a pipe so that the circulated water is used to heat a room or supply heated water, and includes a water heater and a boiler.
[0004] Such a combustion apparatus includes a burner that combusts fuel gas to generate high-temperature thermal energy, a combustion chamber in which combustion of a mixture of air and gas is performed by the flame generated from the burner, a heat exchanger in which heat exchange is performed between exhaust gas having passed through the combustion chamber and water having passed through the inside of the pipe, and an exhaust gas duct that discharges, to the outside, the exhaust gas in which heat exchange has been performed in the heat exchanger, and an exhaust flue for discharging the exhaust gas to the outside of a building is connected to the exhaust gas duct.
[0005] Since the exhaust gas discharged to the outside through the exhaust flue is high-temperature gas, the exhaust flue is made of aluminum or stainless steel as a heat-resistant metal material, so that there is a problem that manufacturing costs increase.
[0006] In case of some countries, when the temperature of the exhaust gas discharged through the exhaust flue is low, the exhaust flue is allowed to be made of an inexpensive synthetic resin material, but the exhaust gas having passed through the heat exchanger is high temperature gas, so that the exhaust flue is difficult to be made of the synthetic resin material.
[0007] Meanwhile, the exhaust gas exhausted to the outside through the exhaust flue contains high-temperature heat, and therefore thermal energy loss may occur when the exhaust gas is discharged to the outside as is. As the prior art for solving the above-described problem, Korean Patent Publication No. 10-2007-0032866 has been disclosed.
[0008] By the above-described prior art, heat exchange is performed between air flowing from the outside and exhaust gas discharged to the outside, so that thermal energy loss may be minimized.
[0009] In this case, in order to perform heat exchange in the exhaust flue, the exhaust flue is required to be made of a metal material having superior thermal conductivity, but the exhaust flue made of the metal material is expensive so that there is an economic disadvantage.
SUMMARY
[0010] The present invention is directed to providing a combustion apparatus having an intake air/exhaust air heat exchanger, which may prevent thermal energy loss by heating intake air using the waste heat of high-temperature exhaust gas having passed the heat exchanger, and improve the thermal efficiency according to the temperature rise of the intake air.
[0011] The present invention is also directed to providing a combustion apparatus having an intake air/exhaust air heat exchanger, in which an exhaust flue may be made of a synthetic resin material by lowering the temperature of exhaust gas exhausted to the outside, and thereby may reduce the installation costs.
[0012] One aspect of the present invention provides a combustion apparatus including: a burner that generates exhaust gas; a blower that supplies external air to the burner; a main heat exchanger that absorbs heat from the exhaust gas generated by the burner; an exhaust gas duct that discharges the exhaust gas having passed through the main heat exchanger to the outside; an intake air duct that introduces the external air to the blower; an intake air/exhaust air heat exchanger that exchanges heat between the external air introduced to the blower and the exhaust gas discharged through the exhaust gas duct using a thin film plate interposed therebetween; and an exhaust flue that discharges the exhaust gas having passed through the intake air/exhaust air heat exchanger to the outside.
[0013] Here, the main heat exchanger may include a sensible heat exchanger that absorbs combustion sensible heat generated by the burner and a latent heat exchanger that absorbs latent heat of the exhaust gas having passed through the sensible heat exchanger.
[0014] Also, the intake air/exhaust air heat exchanger may include a plurality of thin film plates, each being formed into a flat plate shape, a first spacer that is provided to separate the thin film plates from one another and forms an intake air passage connected to the intake air duct, and a second spacer that is alternately laminated and arranged with the first spacer while being connected to the exhaust gas duct to form an exhaust gas passage so that heat exchange is performed between the exhaust gas passage and the intake air passage.
[0015] Also, a temperature sensor for measuring the temperature of the exhaust gas passing through the inside of the exhaust gas duct may be provided in the exhaust gas duct, and a control unit may control to stop the operation of the combustion apparatus when the temperature measured by the temperature sensor is a set temperature or higher.
[0016] Also, each of the first spacer and the second spacer may be formed into a curved shape so that peaks and valleys are formed thereon, a thickness of each of the thin film plates and the first and second spacers may be 20 to 70 μm, and the thin film plates and the first and second spacers may be made of thermoplastic resin.
[0017] Also, the exhaust gas may be introduced from an upper side of the exhaust gas passage and flow vertically downward, a distance between the thin film plates that form the intake air passage may be smaller than a distance between the thin film plates that form the exhaust gas passage, and the exhaust flue may be made of a synthetic resin material.
[0018] Also, a condensed water discharge pipe for discharging condensed water may be connected to the outlet side exhaust gas duct connected to the exhaust gas passage.
[0019] According to the combustion apparatus of the present invention, by heating intake air using the waste heat of exhaust gas exhausted to the outside, the efficiency of the combustion apparatus may be improved.
[0020] Also, by manufacturing an intake air/exhaust air heat exchanger using a thin film, instead of manufacturing an existing heat exchanger formed of an expensive metal plate, the manufacturing costs may be reduced, the heat exchangers having various sizes may be manufactured, and the durability of the heat exchanger may be improved thanks to excellent chemical performances such as water resistance, salt resistance, chemical resistance, and the like.
[0021] Also, by lowering the temperature of exhaust gas exhausted to the outside, the exhaust flue may be made of a synthetic resin material, and thereby may reduce the installation costs of the combustion apparatus.
[0022] Also, by making the dropping direction of condensed water coincide with the flowing direction of exhaust gas, the heat exchange efficiency in the intake air/exhaust air heat exchanger may be improved.
[0023] Also, by making the distance between thin film plates forming an intake air passage smaller than the distance between thin film plates forming an exhaust gas passage, the heat exchange area may be increased and thereby the efficiency may be improved.
BRIEF DESCRIPTION OF DRAWINGS
[0024] FIG. 1 is a schematic cross-sectional view showing a combustion apparatus according to an embodiment of the present invention;
[0025] FIG. 2 is a perspective view showing an intake air/exhaust air heat exchanger according to an embodiment of the present invention;
[0026] FIG. 3 is a view showing an intake air/exhaust air heat exchanger according to another embodiment of the present invention; and
[0027] FIG. 4 is a perspective view showing an intake air/exhaust air heat exchanger according to another embodiment of the present invention.
DESCRIPTION OF REFERENCE NUMERALS OF THE MAIN ELEMENTS IN DRAWINGS
[0000]
1 : combustion apparatus
100 : blower
110 and 110 - 1 : inlet side intake air ducts
120 and 120 - 1 : outlet side intake air ducts
200 : burner
300 : main heat exchanger
310 : sensible heat exchanger
320 : latent heat exchanger
410 : inlet side exhaust gas duct
420 : outlet side exhaust gas duct
430 : temperature sensor
440 : exhaust flue
500 , 500 - 1 , and 500 - 2 : intake air/exhaust air heat exchangers
510 , 510 - 1 , 510 - 2 , 511 , 511 - 1 , and 511 - 2 : intake air passages
520 , 520 - 1 , 520 - 2 , 521 , 521 - 1 , and 521 - 2 : exhaust gas passages
530 , 530 - 1 , 530 - 2 , 531 , 531 - 1 , 531 - 2 , 532 , 532 - 1 , 532 - 2 , 533 , 533 - 1 , and 533 - 2 : thin film plates
541 , 541 - 1 , 541 - 2 , 542 , 542 - 1 , 542 - 2 : first spacers
540 , 540 - 1 , 540 - 2 , 542 , 542 - 1 , and 542 - 2 : second spacers
DETAILED DESCRIPTION
[0046] Hereinafter, configurations and operations of preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.
[0047] FIG. 1 is a schematic cross-sectional view showing a combustion apparatus according to an embodiment of the present invention, and FIG. 2 is a perspective view showing an intake air/exhaust air heat exchanger according to an embodiment of the present invention.
[0048] The combustion apparatus 1 according to the present invention includes a burner 200 that combusts a mixture of air and gas to generate exhaust gas, a blower 100 that supplies external air to the burner 200 , a main heat exchanger 300 that absorbs heat from the exhaust gas generated by the burner 200 , exhaust gas ducts 410 and 420 that discharge the exhaust gas having passed through the main heat exchanger 300 to the outside, intake air ducts 110 and 120 that introduce the external air to the blower 100 , an intake air/exhaust air heat exchanger 500 that exchanges heat between the external air introduced to the blower 100 and the exhaust gas discharged through the exhaust gas ducts 410 and 420 using thin film plates 530 , 531 , 532 , and 533 interposed therebetween, and an exhaust flue 440 that discharges the exhaust gas having passed through the intake air/exhaust air heat exchanger 500 to the outside.
[0049] The combustion apparatus 1 according to the present invention may be applied to a boiler that performs heating or a water heater that supplies heated water, or applied to a device that combines heating and supply of heated water.
[0050] The main heat exchanger 300 includes a sensible heat exchanger 310 that absorbs combustion sensible heat generated by the burner 200 and a latent heat exchanger 320 that absorbs latent heat of the exhaust gas having passed through the sensible heat exchanger 320 .
[0051] In the latent heat exchanger 320 , condensed water is generated due to the absorption of the latent heat of the exhaust gas, and the generated condensed water is discharged through a condensed water discharge port 610 . A water trap (not shown) having a siphon structure to ensure that the water trap is kept in a state of being filled with the condensed water at a predetermined water level or more is connected to the condensed water discharge port 610 , so that the exhaust gas is prevented from being introduced into the room through the condensed water discharge port 610 during the operation of the boiler.
[0052] The intake air/exhaust air heat exchanger 500 is provided at a point in which the intake air ducts 110 and 120 and the exhaust gas ducts 410 and 420 cross each other, so that heat exchange between the intake air and the exhaust gas is performed.
[0053] The intake air ducts 110 and 120 includes the inlet side intake air duct 110 that supplies the intake air introduced from the outside to the intake air/exhaust air heat exchanger 500 , and the outlet side intake air duct 120 that is provided between the intake air/exhaust air heat exchanger 500 and the blower 100 so that the intake air that has been heated while passing through the intake air/exhaust air heat exchanger 500 is supplied to the blower 100 .
[0054] An intake port 111 is connected to the inlet side intake air duct 110 , and an intake flue (not shown) for the inflow of external air is provided in the intake port 111 .
[0055] In the present embodiment, a case in which the outlet side intake air duct 120 is connected to the blower 100 has been described, but a case in which there is no outlet side intake air duct 120 is possible. In this case, the intake air having passed through the intake air/exhaust air heat exchanger 500 is discharged to the interior space of the combustion apparatus 1 , and when the blower 100 is operated, air in the interior space of the combustion apparatus 1 is introduced into the blower 100 .
[0056] The exhaust gas ducts 410 and 420 includes the inlet side exhaust gas duct 410 that allows the exhaust gas having passed through the main heat exchanger 300 to be introduced into the intake air/exhaust air heat exchanger 500 , and the outlet side exhaust gas duct 420 that allows the exhaust gas that has been cooled by heat exchange performed between the exhaust gas and the intake air to be discharged to the outside.
[0057] An exhaust port 421 is connected to the outlet side exhaust gas duct 420 , and the exhaust flue 440 that is connected to the outside of a building in order to discharge the exhaust gas to the outside is connected to the exhaust port 421 .
[0058] The exhaust gas is discharged to the outside in a state in which the temperature of the exhaust gas is lowered by heat exchange performed between the intake air and the exhaust gas while passing through the intake air/exhaust air heat exchanger 500 , and therefore the exhaust flue 440 may be made of a synthetic resin material. When the exhaust flue 440 is made of the synthetic resin material, it is possible to reduce the manufacturing costs of the combustion apparatus 1 .
[0059] In the inlet side exhaust gas duct 410 , a temperature sensor 430 for measuring the temperature of the exhaust gas passing through the inside of the inlet side exhaust gas duct 410 is provided. When the temperature measured by the temperature sensor 430 is a temperature set in a control unit (not shown) or higher, the control unit controls to stop the operation of the combustion apparatus 1 in order to protect the intake air/exhaust air heat exchanger 500 constituted of thin films.
[0060] In the present embodiment, a case in which the temperature sensor 430 is provided in the inlet side exhaust gas duct 410 has been described, but a case in which the temperature sensor 430 is provided in the outlet side exhaust gas duct 420 is possible. In this case, whether there is a need to protect the intake air/exhaust air heat exchanger 500 constituted of the thin films from the temperature of the exhaust gas passing through the inside of the outlet side exhaust gas duct 420 may be determined
[0061] The intake air/exhaust air heat exchanger 500 includes the plurality of thin film plates 530 , 531 , 532 , and 533 , each being formed into a flat plate shape, first spacers 541 and 543 which are provided to separate the thin film plates 530 , 531 , 532 , and 533 from one another and form intake air passages 510 and 511 connected to the intake air ducts 110 and 120 , and second spacers 540 and 542 which are alternately laminated and arranged with the first spacers 541 and 543 while being connected to the exhaust gas ducts 410 and 420 to form exhaust gas passages 520 and 521 so that heat exchange is performed between the exhaust gas passages 520 and 521 and the intake air passages 510 and 511 .
[0062] Each of the thin film plates 530 , 531 , 532 , and 533 , the first spacers 541 and 543 , and the second spacers 540 and 542 may be formed of a significantly thin film, and it is preferable that the thickness of the film be in a range of approximately 20 to 70 μm in consideration of the heat transfer coefficient.
[0063] When the thickness of the film is relatively large, the heat transfer efficiency between the exhaust gas and the intake air is reduced, so that the exhaust gas is discharged in a state in which the temperature of the exhaust gas is relatively high and the intake air is introduced in a state in which the temperature of the intake air is relatively low, and therefore the outlet side exhaust gas duct 420 is difficult to be made of the synthetic resin material, which leads to an increase in the costs. In addition, the temperature of the mixture of air and gas introduced into the burner 200 cannot be raised, so that the efficiency is reduced and an amount of thermal energy that is wasted as waste heat is increased, which leads to a reduction in the efficiency.
[0064] Each of the first spacers 541 and 543 and the second spacers 540 and 542 is formed into a curved shape so that peaks and valleys are formed thereon, and they serve to support the thin film plates 530 , 531 , 532 , and 533 in such a manner that the neighboring thin film plates 530 , 531 , 532 , and 533 are spaced apart from one another by a predetermined interval.
[0065] The thin film plates 530 , 531 , 532 , and 533 , the first spacers 541 and 543 , and the second spacers 540 and 542 are made of thermoplastic resin such as polypropylene. In this case, the thermal conductivity of the material itself is not significantly high, but the thermal conductivity may be improved by reducing the thickness.
[0066] By the above-described configuration, the intake air/exhaust air heat exchanger 500 is provided to absorb the waste heat of the exhaust gas so that the energy efficiency may be increased, and the intake air is heated using the exhaust gas and then supplied to the burner 200 so that the combustion efficiency may be improved. In addition, the exhaust gas is discharged to the outside after the temperature of the exhaust gas has dropped in the intake air/exhaust air heat exchanger 500 , and therefore the installation costs of the combustion apparatus 1 may be reduced when the outlet side exhaust gas duct 420 is made of a synthetic resin material.
[0067] In addition, the intake air/exhaust air heat exchanger 500 may be manufactured using the thin film, and therefore heat exchangers having various sizes may be manufactured, and the durability of the heat exchanger may be improved thanks to excellent chemical performances such as water resistance, salt resistance, chemical resistance, and the like.
[0068] FIG. 3 is a view showing an intake air/exhaust air heat exchanger according to another embodiment of the present invention. Here, FIG. 3( a ) shows a state in which an intake air duct and an exhaust gas duct are coupled to the intake air/exhaust air heat exchanger, and FIG. 3( b ) shows a cross-sectional structure of the intake air/exhaust air heat exchanger.
[0069] Referring to FIG. 3( a ), in an intake air/exhaust air heat exchanger 500 - 1 , an inlet side intake air duct 110 - 1 through which external air is introduced and an outlet side intake air duct 120 - 1 for supplying the external air having passed through the intake air/exhaust air heat exchanger 500 - 1 to the blower 100 side are provided. In addition, in the intake air/exhaust air heat exchanger 500 - 1 , an inlet side exhaust gas duct 410 - 1 through which exhaust gas on which heat exchange has been performed in the main heat exchanger 300 passes and an outlet side exhaust gas duct 420 - 1 for discharging, to the outside, the exhaust gas on which heat exchange with the intake air has been performed are provided.
[0070] Referring to FIG. 3( b ), the intake air/exhaust air heat exchanger 500 - 1 includes a plurality of thin film plates 530 - 1 , 531 - 1 , and 532 - 1 , first spacers 541 - 1 and 543 - 1 which are provided to separate the thin film plates 530 - 1 , 531 - 1 , and 532 - 1 from one another and form intake air passages 510 - 1 and 511 - 1 connected to the intake air ducts 110 - 1 and 120 - 1 , and second spacers 540 - 1 and 542 - 1 which are alternately laminated and arranged with the first spacers 541 - 1 and 543 - 1 while being connected to the exhaust gas ducts 410 - 1 and 420 - 1 to form exhaust gas passages 520 - 1 and 521 - 1 so that heat exchange is performed between the exhaust gas passages 520 - 1 and 521 - 1 and the intake air passages 510 - 1 and 511 - 1 .
[0071] Here, the inlet side exhaust gas duct 410 - 1 is connected to an upper side of the intake air/exhaust air heat exchanger 500 - 1 , and the outlet side exhaust gas duct 420 - 1 is connected to a lower side of the intake air/exhaust air heat exchanger 500 - 1 . When connection is achieved in this manner, the exhaust gas is introduced from upper sides of the exhaust gas passages 520 - 1 and 521 - 1 inside the intake air/exhaust air heat exchanger 500 - 1 and flows vertically downward.
[0072] As shown in FIG. 2 , when the exhaust gas passages 520 and 521 are disposed in the horizontal direction, condensed water generated in the intake air/exhaust air heat exchanger 500 is brought into contact with the exhaust gas flowing in the horizontal direction while the condensed water drops within the exhaust gas passages 520 and 521 , and thereby may reduce the heat exchange efficiency.
[0073] In the case of the embodiment of FIG. 3 , by making the dropping direction of the condensed water coincide with the flowing direction of the exhaust gas, a reduction in the heat exchange efficiency in the intake air/exhaust air heat exchanger 500 - 1 may be prevented.
[0074] Meanwhile, the condensed water may be generated in the exhaust gas passages 520 - 1 and 521 - 1 of the intake air/exhaust air heat exchanger 500 - 1 , and the generated condensed water may be discharged through a condensed water discharge pipe 450 - 1 connected to the outlet side exhaust gas duct 420 - 1 . The condensed water discharge pipe 450 - 1 is connected to the above-described water trap, so that the exhaust gas is discharged through the exhaust flue without being discharged to the room through the condensed water discharge pipe 450 - 1 .
[0075] FIG. 4 is a perspective view showing an intake air/exhaust air heat exchanger according to another embodiment of the present invention.
[0076] An intake air/exhaust air heat exchanger 500 - 2 includes a plurality of thin film plates 530 - 2 , 531 - 2 , 532 - 2 , and 533 - 2 , first spacers 541 - 2 and 543 - 2 which are provided to separate the thin film plates 530 - 2 , 531 - 2 , 532 - 2 , and 533 - 2 from one another and form intake air passages 510 - 2 and 511 - 2 connected to intake air ducts, and second spacers 540 - 2 and 542 - 2 which are alternately laminated and arranged with the first spacers 541 - 2 and 543 - 2 while being connected to exhaust gas ducts to form exhaust gas passages 520 - 2 and 521 - 2 so that heat exchange is performed between the exhaust gas passages 520 - 1 and 521 - 1 and the intake air passages 510 - 2 and 511 - 2 .
[0077] Condensed water may be generated in the exhaust gas passages 520 - 2 and 521 - 2 , and it is preferable that a distance h 1 between the thin film plates 530 - 2 to 531 - 2 and 532 - 2 to 533 - 2 forming the exhaust gas passages 520 - 2 and 521 - 2 be maintained at such a distance that the condensed water can be smoothly discharged.
[0078] In contrast, only air flows in the intake air passages 510 - 2 and 511 - 2 , and therefore the distance h 1 between the thin film plates 532 - 2 and 533 - 2 forming the intake air passages 510 - 2 and 511 - 2 may be smaller than a distance h 2 between the thin film plates 531 - 2 and 532 - 2 forming the exhaust gas passages 520 - 2 and 521 - 2 .
[0079] In this manner, when the distance h 1 between the thin film plates 532 - 2 and 533 - 2 forming the intake air passages 510 - 2 and 511 - 2 is made smaller, an area in which heat exchange is performed is increased together with an increase in the number of the intake air passages 510 - 2 and 511 - 2 and the exhaust gas passages 520 - 2 and 521 - 2 within the intake air/exhaust air heat exchanger 500 - 2 having the same size, thereby improving the efficiency.
[0080] While the invention has been shown and described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
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The present invention relates to a combustion apparatus having an intake air/exhaust air heat exchanger. The combustion apparatus comprises: a burner for generating exhaust gas; a blower for supplying external air to the burner; a main heat exchanger for absorbing heat from the exhaust gas generated by the burner; an exhaust gas duct for discharging the exhaust gas having passed the main heat exchanger to the outside; an intake air duct for introducing external air to the blower; an intake air/exhaust air heat exchanger for exchanging heat between the external air introduced to the blower and the exhaust gas discharged through the exhaust gas duct using a thin film plate disposed therebetween; and an exhaust flue for discharging the exhaust gas having passed the intake air/exhaust air heat exchanger to the outside.
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This is a continuation-in-part of application Ser. No. 07/697,239, filed Apr. 29, 1991, now abandoned.
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to the field of toilet flushing systems that utilize a floating connection in connection with the valve stem of the flapper flush valve to provide a variable amount of water per flush. The amount of water consumed per flush in these devices is determined by the amount of time one holds down the flush handle. The float can be set so that a normal depressing and releasing of the handle will produce a flush with the absolute minimum of water used. Larger volumes can be used to flush by holding the handle down for longer periods of time. In the present invention, a float is provided that is slidable along the valve stem to maintain the valve stem in vertical position throughout the flush without the need for a valve stem guide.
In most toilet apparatus of this type, it is necessary that the float that is in contact with the flapper valve (as opposed to the float in connection with the inlet valve for refilling the tank be partially buoyant and able to be lifted straight up, away from the flapper valve seat, so that its buoyancy will keep the valve open for a time to permit flushing. To achieve this, most prior art devices provide for a guide means in connection with this float to assure that it moves straight upward. See for example U.S. Pat No. 4,183,107. The present invention eliminates the need for this guide means. The term flush valve properly includes a pivotal flapper in connection with a discharge opening. The flapper is simply a pivotal stopper for the opening, "flapper value" as used in this spec to refer to the flapper alone.
SUMMARY OF THE INVENTION
An improved toilet flushing apparatus of the type that provide variable amount of water per flush. The improvement resides in the use of a sliding valve stem having a stop attached thereto that is slidable up and down through an aperture in the flush valve. The sliding valve stem and the float in connection with it maintain the vertical position of the stem as water level in the tank begins raising the float to its normal resting position upon the refilling of the tank.
It is the object of this invention to eliminate the need for a flush valve stem guide in toilet flushing apparatus with variable flush volume control using a flapper valve.
Another objective of the invention is to provide an apparatus to maintain the flush valve stem in a vertical position at all times in a toilet with variable flush volume control.
Other advantages of the invention should be readily apparent to those skilled in the art once the invention has been described.
DESCRIPTION OF THE FIGURES
FIG. 1 shows the overall design used with a flapper valve.
FIG. 2 shows a partial cutaway, with annular grooves, along the length of part 3 and a flapper valve having a centrally located cavity and an alternate position for the aperture 8A.
FIG. 3 shows a close up view of the float, flapper valve and valve stem.
FIG. 4 shows the prior art with valve stem guide means 13 and an adjustable flush valve 14 in relation to valve stem 3 or 3A.
FIG. 5 is a buoyant float composed of 3 parts.
FIG. 6 and FIG. 7 show alternate positions for the apertures 8B and 8C for the valve stem, FIG. 7 is a washer type flush valve and 2V is a rubber (or similar material) washer that seals against 3B at rest. FIG. 6 is a flapper valve with an extended top portion so that the aperture 8B is extended away from the central portion of the flapper valve.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The invention may be used as part of a kit for retrofitting attachments on existing toilet flush mechanism that are of the type that may be adjusted for giving smaller flushes. The amount of water to be used in a flush may be varied by positioning the float 1 at higher or lower points along the stem 3 or 3A a higher position gives a smaller flush.
By trial and error, one may arrive at that position along the stem which will provide a flush that uses the minimum amount of water necessary to flush. The float may be frictionally set at this position for future quick flushes. One may increase this flush volume by holding the flush handle down for some period of time greater than the normal push and release (quick flush). Fuller flushes are achieved by a longer hold down on the handle.
Usually, a chain or rod or other flexible means 11 connects the flush handle (10) to a position near the top of the valve stem 3A so that movement of the flush handle will result in the lifting of the flush valve and release the water in the toilet tank. The float 1 is just buoyant enough so that it will not hold up the flapper valve 2 when at rest in the tank, but will keep the valve open for a short time after starting the initial flush to insure that the proper amount of water is let out to allow a flush. It is held by its own natural buoyancy and will hold up the valve until the water level in the tank lowers and the float falls with the water level. This allows the flapper to fall and close the flush valve to allow the tank to refill by a refilling means.
In prior art toilet mechanisms of the variable flush variety, shown in FIG. 4, the valve stem may tilt in relation to the flush valve and as such must be supported by a guide 13 to keep it in the vertical position. The present invention also utilizes a movable valve stem but, in this application, without the guide. To prevent the valve stem from tipping over in lieu of the stem guide, the stem 3A is permitted to move through an aperture 8 in the flush valve 2 during the lowering of the float 1 after the initial flush. The flapper valve (or flush valve) is non-buoyant and is pivotally connected to the bottom of the toilet tank.
The flush valve stem 3A provides a rigid vertical attachment of the flush valve 2 to the flushing handle 10. "Rigid" in the sense that the rod is rigid, the connection between the stem and the valve is not that connection is slidable. The end 4 of the rod 3A can move down through the seal opening or aperture 8 in the flush valve so that the rod 3A will move downward, after the water level falls below the float 1.
When in the rest position, before and immediately after an initial flushing actuation the end 4 fits against the opening 8 and forms a seal that does not leak. When the toilet is flushed initially, the handle moves the stem, float, and flush valve upward and water exits the flush valve. As the water level falls below the float, the stem moves downward through the aperture and the float 1 will fall also at this time. Once the flush valve is sealed again, the float 1 will gradually move upward as the water fills the tank. At the same time, the bottom 4 of the rod 3A will come up in connection with the aperture until it eventually reaches the seal opening 8, again, where it will be sealed until the next flush.
The end of the stem 4 is made so that it will form a seal with opening 8 as the rod moves up when the rise in the water level raises the float 1 and stem 3A.
The amount of volume for each flush may be regulated through the use of the sliding float by placing the sliding float at different heights along the stem. The higher up along the stem that the float is attached then the sooner that the water level will fall to the level of the float, when that happens, the valve will soon close as the water level falls a little more. When the float is lower on the stem, the water level will fall a long way before reaching the float and thus a greater volume of water will escape before the flush valve closes. In this way, the volume of flush may be varied.
Note that the aperture 8 is so small as to have little or no effect on the water level. The aperture is just large enough to permit the sliding of the stem without causing a large volume of water to escape and prevent refilling.
When one wishes to retrofit the old toilet, the stem may be replaced by one with (or without) 6 so that the float 1 may be locked into place by frictional engagement with the stem. The valve 4 may be replaced by an O-ring 5 at the end of the stem which engages the aperture 8. Or one can use the valve type shown in FIG. 3. FIG. 5 shows an alternate arrangement for the float 1A which is of three-piece construction, parts 17, 20 and 1A. 17 is a rubberized grommet with a groove 22 which is held in place by the harder piece 1A. 1A can be snap-fit or otherwise fit with bottom piece 20.
In this way, the valve stem is held vertical (or nearly vertical) throughout the filling of the tank and at all other times. The use of the guide rod is not needed. Thus, the device can be used to retrofit onto existing tanks easier. The device can also be retrofit onto tanks with different ends at the stems, e.g. the ball type shown in FIG. 1 or the type shown in FIG. 3. Other obvious means to keep the stem from being pulled upward through the aperture 8 may be used so that the aperture 8 will be sealed.
Note that it is not necessary that the aperture be in the flapper valve, it may be at one side of the flapper valve as shown in FIGS. 6 and 7. There, the aperture is shown as 8B and 8C and it can be seen that it is at one side. In this case, the end of the stem does not need to seal against the aperture. FIGS. 6 and 7 represent two types of flapper valves. That shown in FIG. 7 is known as a "washer type." In FIG. 7 the neck of part 3B is free to move up and down in central aperture of flapper valve 2V thereby making it unnecessary for valve stem 3A to be able to move freely up and down in aperture 8C so that said valve stem 3A and float 1 may remain in a vertical manner at all times. The head of 3B seals against the aperture in washer 2V when the float lifts upper part 2B this causes the sealing of the aperture by the lowering of 2V against the outlet (not shown).
In the present invention, the valve stem guide is not needed to hold the valve stem and float in a vertical manner. When the water in the tank elevates the float, the stem and float are elevated in a vertical position and, when water level is below float, the stem hangs from the lifter arm 10 thereby maintaining the stem and float in a vertical manner at all times.
The small aperture in the flapper replaces the use of a separate valve stem guide.
Note on FIG. 2 that there is an alternate position for the valve stem aperture at 8A. Either the aperture 8 or aperture 8A may be used but only one at a time. 5 in FIG. 2 is a stop to keep the valve stem from coming out of aperture 8, any stop may be used it does not have to seal water tight as the flush valve in FIG. 2 can seal itself against the outlet. The valve stem in FIG. 2 has limited movement within the cavity (note the cavity referred to is below aperture 8 in FIG. 2) through the use of the stop 5.
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An improved toilet flush valve for variable volume toilet flushing systems. The present improvement uses a float adjustable attached to a flapper valve by a rigid stem to vary the flush volume. The stem and flapper valve eliminate the need for a valve item guide to maintain the valve stem vertical as the stem is movably retained through an aperture in the flapper valve. Several embodiments are disclosed.
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RELATED APPLICATION
[0001] This application claims priority from European Patent Application 13154316.7 filed on Feb. 7, 2013, the entirety of which is incorporated herein by reference.
TECHNICAL FIELD
[0002] The present disclosure relates to clothes dryers and, more particularly, to clothes dryers that distribute air through one or more lifters.
BACKGROUND
[0003] JP-A-9056991 describes a lifter fixed at the periphery part of a rotary drum and cylindrical seals are fixed at the outer periphery of an air intake plenum and of an air exhaust plenum, so that a circulation passage is formed on the back of the rear wall of the drum. The use of two concentric air plenum chambers and related seals makes the above known solution quite complex and not easy to be implemented. Moreover in the above known solution the process hot air is flowing always and entirely through the lifters, even if the lifters are in an upper position during drum rotation. In this condition, i.e. when the lifters are not in contact with clothes, the effectiveness of having air flowing in the lifter is substantially reduced. Another disadvantage of the above known solution is that it cannot be adapted to traditional dryers where air flow enters the drum from a perforated rear wall and leaves the drum from an aperture placed adjacent the front opening of the drum.
SUMMARY
[0004] It is an object of this disclosure to provide a tumble clothes dryer that does not present the above disadvantages and which can provider higher drying performances, better fabric care and reduced wrinkles.
[0005] The above object is reached thanks to the features listed in the appended claims.
[0006] One of the most relevant technical features of a dryer according to this disclosure is the use of a distribution device in the air inlet plenum chamber capable of delivering air to the drum either indirectly, i.e. through one or more lifters, or directly, i.e. though a rear perforated wall of the drum.
[0007] According to this disclosure, the distribution device is a shaped air plenum chamber which faces only a lower portion of the rear perforated wall, from its side opposite to the drum, so that air is delivered to the drum only though the lower portion of the rear perforated wall. Therefore, when the position of the lifter during rotation of the drum corresponds to the shaped air plenum chamber, air is flowing entirely or partially through the lifter, and when the position of the lifter does not correspond to said air plenum chamber, air is flowing through the plurality of holes of the rear wall of the drum facing the shaped air plenum chamber. The shape of said plenum chamber, together with the shape of an air conveying base portion of the lifter orthogonal to the active portion of the lifter on the drum side wall (such base portion covering, at a predetermined distance, a part of the perforated rear wall of the drum in order to create a sort of inner chamber) will be responsible on the amplitude of arc during which air is delivered through the lifter.
[0008] In one example, the shape of the base portion of the lifter covers substantially a circular sector covering from 60° to 100° of arc of the perforated rear wall of the drum, while the air plenum chamber covers an area a bit wider than said base portion of the lifter, so that at least a percentage of process air flows always through the perforated wall also when the lifter, during its rotation with the drum, it is in a lower portion of the drying chamber. This has been found beneficial in terms of drying efficiency and energy saving.
[0009] The use of lifters for blowing air into the drum as described herein can be implemented without significant modification of existing machines. Moreover, as described herein the air is flowing through the lifter only if this latter is aligned with the distribution device (i.e. inlet air plenum chamber). In this way air flows in the lifter only when this latter is in contact with clothes, i.e. in the lower part of its circular trajectory.
[0010] Another advantage derives from use of a dedicated cycle and the use of separate actuation for drum tumbling and air blowing that enables energy saving and reduced fabric shrinkage. For instance, the use of “blowing lifters” (i.e. use of lifters though which process air can be fed to the drum) increases significantly the drying evenness with respect to traditional dryers, particularly because air flows where it is needed, towards clothes placed in the bottom of the drum, on the lifter, where in the above known solution most of the air would flow through the upper lifter and only a limited part would flow through clothes therefore reducing significantly the efficiency of the overall drying process.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Further advantages and features of this disclosure will be clear from the following detailed description, with reference to the attached drawings, in which:
[0012] FIG. 1 is an isometric view of an example clothes tumble dryer;
[0013] FIG. 2 is an isometric enlarged view of the inside of the drum of FIG. 1 ;
[0014] FIG. 3 is an isometric view of the rear of the drum of FIGS. 1 and 2 ;
[0015] FIG. 4 is a partial cross-sectional view of a detail of FIG. 2 ;
[0016] FIG. 5 is a front view of the perforated rear wall of the drum where the shape of the distributor is shown in solid and dotted line; and
[0017] FIG. 6 is a schematic view of how a clothes dryer according to this disclosure works.
DETAILED DESCRIPTION
[0018] With reference to FIG. 1 , an example tumble dryer 10 includes a cabinet 12 having an upper wall 12 a, a front wall 12 b provided with a hingedly mounted door 14 , side walls 12 c and a rear wall 12 d. Inside the cabinet 12 a rotating drum 16 is mounted which is actuated by an electric motor (not shown) and which defines a drying chamber 17 . The drum 16 includes at least one lifter 18 having a plurality of holes 20 for air passage. The lifter 18 may be hollow. The lifter 18 includes a rear base portion 18 a covers a portion of a rear perforated wall 16 a of the drum in order to convey air entering through the perforated wall 17 a towards the holes 20 of the lifter 18 . The rear base portion 18 may have a triangular or circular sector shape. The base portion 18 a defines with the facing portion of the rear wall 16 a of the drum 16 a sort of inner chamber 19 (see FIG. 4 ) which covers an arc ranging preferably from 60 to 100° and which communicates with the portion of the lifter 18 fixed to the side wall of the drum 16 . The clothes dryer 10 may also have a dispensing system for dispensing treating chemistries into the drum 16 , and including a reservoir 22 that is closed by a cover 24 . The clothes dryer 10 is also provided with a controller 26 that may receive input from a user through a user interface 28 for selecting a cycle of operation.
[0019] The clothes dryer 10 also includes an air inlet channel 30 (see FIG. 6 ) and an outlet channel 32 , a heating system (not shown) that heats air entering the drum (e.g. by means of resistors, heat exchangers, etc.), and a blower (not shown) that makes air flowing across the drum 16 .
[0020] The drum outlet 32 , where a removable filter 33 for removing fluff or lint is placed, can be eventually connected to the drum inlet 30 thus realizing a closed loop system in which heat exchangers, resistors, heat pump, etc. control the condensation and heating process. As an alternative the drum outlet 32 can be connected to an air vent.
[0021] The lifter 18 functions not only to increase the heat exchange efficiency between air and clothes and improve the evenness of the drying result by means of clothes redistribution during the whole cycle, but also to improve the efficiency of hot air distribution.
[0022] A common drawback of known dryers is that when the load size increases to almost fill the drum volume, the efficiency of the lifter in redistributing the load within the drum is decreased thus leading to the risk of damaging the clothes that are positioned in the rear end of the dryer (where temperatures are higher) and reducing the evenness of drying results.
[0023] With a lifter design that allows not only the hot air to flow through the lifter 18 but also by means of a distribution of air through the lifter 18 only during a certain degree of rotation of the drum 16 , the temperature gradient in the drum 16 is reduced and the evenness of drying is increased, reducing also the risk of clothes damaging.
[0024] The above controlled distribution is carried out by means of a shaped fixed distributor 34 which forms an air inlet plenum chamber upstream the drum 16 . The shape of the distributor 34 ( FIG. 5 ) does not corresponds necessarily to the circular sector shape of the base portion 18 a of the lifter 18 , but need not extend higher than the lower half of the drum 16 . In FIG. 5 , two shapes are shown (in dotted and solid lines) which have worked well in tests carried out by the applicants. Such shapes maximize the air flow either though the lifter 18 (when this latter is in the lower positions during rotation) and through clothes adjacent the lifter.
[0025] In other examples, the enhanced lifter design can be combined with a dedicated cycle design, able to stop tumbling when the lifter 18 is located in a position that minimizes the temperature gradient. This approach can furthermore increase the above mentioned advantages and can provide also energy saving benefits due to reduced motor usage. One or more lifters of the type disclosed above can also be used together with one or more typical lifters that do not match the above description. Due to the fact that the lifter 18 is physically connected to the drum 16 , during tumbling it changes its position with respect to the air inlet 34 thus leading to a variable air mass flow rate in the lifter 18 and in the drum 16 . This is clearly shown in FIG. 6 where arrows A show the air flow through the lifter 18 (when this latter is placed in the lower position inside the drum 16 ), and arrows B show the air flow through the rear wall 16 a of the drum 16 when the lifter 18 is in a position not matching the air distributor 34 . This alternating air flow path in the drum 16 creates the conditions for a variable heat flux as well that improves the evenness of drying and fabric care.
[0026] The examples disclosed herein can improve significantly also the drying and fabric care performances with delicate cycles. As described above, aiming to reduce the mechanical action on this type of loads, the tumbling is often reduced or even avoided; this solution has the negative result of increasing the temperature gradient thus leading to the already discussed drawbacks. If the proposed lifter design is used, the machine can be designed to stop tumbling (for the whole cycle or only for part of it, also e.g., using a PWM approach) in a way that the air can flow through the lifter 18 to provide a means to optimize heat flux for these type of loads using appropriate design of the lifter. In some examples, the drum 16 is in a position where the lifter 18 lays on the bottom of the drum 16 , thus having the clothes laying on it. The method used to stop the drum 16 in the correct position is well known in the art and it can be easily transferred from the known solutions for top loader washer for having the door in upwards location to facilitate loading and unloading of the drum.
[0027] Moreover, since air can flow through the lifter 18 , the latter can be designed to host a cartridge containing a fragrance or some other chemical additives to improve quality of drying that can be released in the drum 16 .
[0028] In some examples, the lifter 18 is used with a drum 16 having an air inlet and outlet port on opposite sides thus enabling fine optimization of heat fluxes. Nevertheless the examples disclosed herein can be applied to those drums in which inlet and outlet air connections are located on the same side (with a dedicated air collector similar to air distributor 34 ). In these examples the lifter 18 can be used to convey hot inlet air towards the opposite side of the drum 16 , therefore improving significantly the heat flux distribution in the longitudinal direction.
[0029] FIG. 4 shows a detail of the air distributor 34 which is made preferably by a shaped metal or plastic sheet 35 . In order to increase the efficiency, a sealing means (not shown) can be interposed between the edge of the shaped sheet 35 forming the distributor 34 and the rear wall 16 a of the drum 16 .
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Clothes dryers that distribute air through one or more lifters are disclosed. An example domestic clothes dryer includes a rotating drum defining a drying chamber, an air inlet upstream the drum, and lifter mounted in the drum, wherein said lifter is in communication with the air inlet for distributing air inside the drum through a plurality of openings. An example air inlet includes a shaped air plenum chamber facing a lower portion of a rear perforated wall of the drum and capable of delivering air to said lifter and/or directly to the drum through said rear perforated wall.
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This application claims the benefit of Taiwan application Serial No. 93128635, filed Sep. 21, 2004, the subject matter of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates in general to a manufacturing method of a multi-layer circuit board, and more particularly to a manufacturing method of a multi-layer circuit board embedded with a passive component.
2. Description of the Related Art
The object of creating a larger space within a substrate area with limited space and enhancing the multi-functions of the module is normally achieved by reducing or embedding a passive component so that more space can be used for the installation of active components. And, the multi-layer circuit board embedded with a passive component is thus invented and provided. The above passive component can be components such as a resistor, a capacitor, an inductometer or a voltage controlled quartz oscillator.
Many methods can be used to integrate several film passive components in a multi-layer circuit board. In terms of the manufacturing process of multi-layer circuit board, the key factor lies in the ability of embedding the thick-film or thin film passive component of the kind in the circuit board during manufacturing process. The key factor is how to maintain the electrical precision of the thin film passive component and reduce the variation with the original design after the thin film passive component is integrated into the multi-layer circuit board. An exemplified in Taiwanese Patent Publication No. 518616 “Manufacturing Method of a Multi-Layer Circuit Board with a Passive Component” disclosed on Jan. 21, 2003 is an example focusing on this issue.
Referring to FIG. 1A and FIG. 1B , a multi-layer circuit board with a passive component includes a circuit thin plate 1 whose surface has a patterned circuit layer 2 , a conductive foil 3 , a resistor film 5 , a passivation layer 7 , and a prepreg 9 . The resistor film 5 is deposited on a slightly rough region on a smooth surface of the conductive foil 3 to have a better adhesion, and can be appropriately heated to become solidification. The slightly rough region can be defined according to photoresist micro-film etching, polishing, or other methods. The passivation layer 7 covers up the resistor film 5 . The prepreg 9 is located between the conductive foil 3 and the circuit thin plate 1 . The circuit thin plate 1 , the conductive foil 3 , and the prepreg 9 are stacked together according to a hot-pressing step.
However, the above methods must take into account the manufacturing process ability of the resistor or capacitor. For example, the printing area of the resistor must be carefully controlled, lest the printed resistor might vary with the designed value and cause bias to electrical precision. Therefore, the entire manufacturing process would become more complicated.
In the fields of close-to-mature technology, how to maintain the electrical precision and at the same time simplify the manufacturing process for the current manufacturing process to better fit the needs of next generation products has become an urgent issue to be resolved.
SUMMARY OF THE INVENTION
It is therefore a main object of the invention to provide a manufacturing method of a multi-layer circuit board embedded with a passive component, which can simplify manufacturing process and enhance electrical precision.
Another object of the invention is to provide a manufacturing method of a multi-layer circuit board embedded with a passive component without considering the manufacturing process ability of the resistor or capacitor as well as the variation between the formed components and their original designed values.
The other object of the invention is to provide a manufacturing method of a multi-layer circuit board embedded with a passive component such as a resistor, a capacitor, or an inductometer.
In order to achieve the above object, the invention discloses a manufacturing method of a multi-layer circuit board embedded with a passive component. The method includes the following steps of providing a conductive foil which has a first surface and a second surface and has at least a pair of metal protruding points; mounting a passive component onto corresponding metal protruding points; providing a board having a core substrate with organic insulation layer thereon; stacking the conductive foil and the board, wherein the passive component is embedded in the organic insulation layer; and patterning the conductive foil to form an electrical pattern on the conductive foil.
The organic insulation layer is located between conductive foil and the core substrate.
Besides, at least a through hole can be formed on the core substrate to be electrically connected to the conducting circuit on the conductive foils of the top and the bottom surface of the core substrate.
Further, the core substrate with surface circuit can be formed on the blind hole on the insulation layer for the circuit pattern on the conductive foil to be electrically connected to the conducting circuit on the surface of the core substrate to form a multi-layer circuit board.
Moreover, the multi-layer circuit board can be a structure having a blind hole, a structure having a through hole, or a structure having a blind hole connected with a buried hole.
The characteristics and features of the invention are disclosed in the embodiments below, so that anyone who is skilled in relevant technology will be able to understand and implement the technology of the invention accordingly. Any features and object relevant to the invention can be easily understood from the embodiments, claims and drawings disclosed the invention.
The summary of the invention disclosed above and the embodiments of the invention disclosed below exemplify and explain the principles of the invention and provide further explanations to the claims of the invention.
Other objects, features, and advantages of the invention will become apparent from the following detailed description of the preferred but non-limiting embodiments. The following description is made with reference to the accompanying drawings. Anyone who is skilled in related technology would be able to understand and implement the technology accordingly.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A and FIG. 1B (Prior Art) are cross-sectional views of the manufacturing process of a conventional multi-layer circuit board embedded with a passive component;
FIG. 2A to FIG. 2D are cross-sectional views of the manufacturing process of a multi-layer circuit board embedded with a passive component according to a preferred embodiment of the invention;
FIG. 3A and FIG. 3B show a first example of a circuit pattern formed on the surface of a deposited multi-layer circuit board;
FIG. 4A to FIG. 4B show a second example of a circuit pattern formed on the surface of a deposited multi-layer circuit board; and
FIG. 5 shows a third example of a circuit pattern formed on the surface of a deposited multi-layer circuit board.
DETAILED DESCRIPTION OF THE INVENTION
It is noteworthy that the following drawings are not formulated according to actual scale, but are merely formulated for elaboration. That is, the actual scales and features in various layers of the multi-layer circuit board are not fully reflected.
Referring to FIG. 2A to FIG. 2D , cross-sectional views of the manufacturing process of a multi-layer circuit board embedded with a passive component according to a preferred embodiment of the invention are shown.
As shown in FIG. 2A , at first a conductive foil 11 having at least a pair of metal protruding points 15 is provided on a first surface 17 a . The conductive foil 11 having at least a pair of metal protruding points 15 disclosed above can be procured from external sources by the manufacturer or obtained through a patterning manufacturing process such as the micro-film etching manufacturing process to pattern a conductive foil so to form the metal protruding points 15 on a surface of the conductive foil, as a result of the protruding points 15 with the same material as the conductive foil. The conductive foil 11 can be made of copper, silver, aluminum, palladium or silver palladium, and is preferably made of a copper foil.
As shown in FIG. 2B , a passive component 13 is coupled to corresponding metal protruding points 15 on the first surface 17 a of the conductive foil 11 a . The step of coupling can be performed by hot-pressing for instance. During the hot-pressing process, alignment precision is essential and must be under good control. The above passive component 13 can be a capacitor, a resistor, or an inductometer.
FIG. 2C shows a core substrate 19 , a first organic insulation layer 21 a and a second organic insulation layer 21 b , a first conductive foil 11 a having a passive component 13 , and a second conductive foil 11 b with or without a passive component.
The first organic insulation layer 21 a and the second organic insulation layer 21 b are pressed onto the two lateral sides of the core substrate at the same time first, and a first conductive foil 11 a and a second conductive foil 11 b are pressed onto the first organic insulation layer 21 a and the second organic insulation layer 21 b at the same time. Alternatively, the first organic insulation layer 21 a , the first conductive foil 11 a , the second organic insulation layer 21 b , and the second conductive foil 11 b are respectively located on the two lateral sides of the core substrate 18 , and then the layers and foils are pressed at the same time. It is permitted to press the first organic insulation layer 21 a and the first conductive foil 11 a on one side of the core substrate, and not any other single layer plate and conductive foil is pressed on the other side of the core substrate.
The first surface ( 17 a , 17 b ) of the conductive foil ( 11 a , 11 b ) on which the passive component 13 is disposed comes into contact with the organic insulation layer. The organic insulation layer ( 21 a , 21 b ) can be a prepreg or a liquid resin pasted on the surface of the core substrate 19 . The core substrate 19 can be a metal circuit with patterns on both of the two surfaces or a simple core substrate without any patterns. The core substrate 19 can be made of insulated organic material or ceramic material, such as epoxy resin, polyimide, dimaleatepolyimide resin, or other fiberglass composites such as a conventional FR-4 substrate. The FR-4 substrate can be made of epoxy resin, a fiberglass cloth and an electroplated copper foil for instance. The core substrate 19 is not limited to be made of a single organic material. The core substrate 19 can be composed of various insulation layers as well. The above stacking procedure can be achieved via a hot-pressing step in which alignment precision is essential and must be under good control.
As shown in FIG. 2D , the layers of the multi-layer circuit board 23 deposited through stacking procedure, from top to down, include the first conductive foil 11 a with the passive component 13 , the first organic insulation layer 21 a , the core substrate 19 , the second organic insulation layer 21 b , the second conductive foil 11 b or the second conductive foil 11 b with the passive component 13 .
Refer to FIG. 3A and FIG. 3B , which show a first example of a circuit pattern formed on the surface of a deposited multi-layer circuit board.
In FIG. 3A , at least a through hole 25 is formed through penetrating the first conductive foil 11 a and the second conductive foil 11 b , so that the circuits formed on the first conductive foil 11 a and the second conductive foil 11 b afterwards can be electrically connected via the through holes 25 . Next, a metal layer 27 is formed on the wall of the hole to enable hole connection. The metal layers ( 27 a , 27 b ) are respectively formed on the second surface 17 a ′ of the first conductive foil 11 a and the second surface 17 b ′ of the second conductive foil 11 b to enable the formation of an electrical pattern. The metal layer 27 may includes copper.
The formation of the metal layer 27 , for example the formation method of a copper metal layer, can be achieved through chemical vapor deposition such as physical vapor deposition (PVD), chemical vapor deposition (CVD), electroplated copper, non-plated copper, sputtering, evaporation, arc vapor deposition, ion beam sputtering, laser ablation deposition, plasma enhanced chemical vapor deposition (PECVD) or organic metal. It is preferred to use non-plating method first and the plating method comes second in forming the copper metal layer.
The metal layer ( 27 a , 27 b ) on the top and the bottom surfaces as well as the conductive foil ( 11 a , 11 b ) shown in FIG. 3A are patterned to form the electrical patterns ( 29 a , 29 b ) in FIG. 3B respectively. The above method of patterning the metal layers 27 form the electrical patterns ( 29 a , 29 b ) respectively can be achieved through the manufacturing process of plating the through hole, such as the subtractive approach using the panel.
According to FIG. 3B , the electrical pattern is respectively formed on the top and the bottom conductive foils. However, in the practical application, the electrical pattern can be formed on one of the conductive foils only. Besides, if the core substrate 19 of the deposited multi-layer circuit board has an electrical pattern formed on both the top surface and the bottom surface or on either of the top surface and bottom surface, an external electrical pattern electrically connected to the electrical pattern of the core substrate on the outer surface can alternatively be formed. Refer to FIG. 4A and FIG. 4B , which show a second example of a circuit pattern formed on the surface of a deposited multi-layer circuit board.
As shown in FIG. 4A , at least a pair of blind holes ( 31 a , 31 b ) are formed by hollowing the first conductive foil 11 a , the first organic insulation layer 21 a , the second conductive foil 11 b and the second organic insulation layer 21 b which connect the top surface to the bottom surfaces, so that the circuits 20 of the core substrate 19 respectively covered by the organic insulation layer ( 21 a , 21 b ) are exposed. When a circuit is to be formed on the conductive foil, the circuit can be electrically connected to the circuit 20 of the core substrate 19 covered by organic insulation layer ( 21 a , 21 b ) via the blind holes ( 31 a , 31 b ).
Next, a first metal layer 27 a and a second metal layer 27 b are respectively formed on the top surface and the bottom surface of the multi-layer circuit board 23 . The first metal layer 27 a covers up the first conductive foil 11 a and the inner wall of the blind hole 31 a so as to be connected to the circuit 20 a disposed on the top surface of the core substrate 19 . The second metal layer 27 b covers up the second conductive foil 11 b and the inner wall of the blind hole 31 b disposed on the bottom surface so as to be connected to the circuit 20 b disposed on the bottom surface of the core substrate 19 . The first metal layer or the second metal layer may include copper.
The formation of the metal layer 27 , for example, the formation method of a copper metal layer, can be achieved through chemical vapor deposition such as physical vapor deposition (PVD), chemical vapor deposition (CVD), electroplated copper, non-plated copper, sputtering, evaporation, arc vapor deposition, ion beam sputtering, laser ablation deposition, plasma enhanced chemical vapor deposition (PECVD) or organic metal. It is preferred to use non-plating method first and the plating method comes second in forming the copper metal layer.
As shown in FIG. 4B , the metal layers ( 27 a , 27 b ) on the top and the bottom surfaces are respectively patterned to form the electrical patterns ( 29 a , 29 b ) electrically connected the circuit ( 20 a , 20 b ) disposed on the top and the bottom surfaces of the core substrate 19 . The deposited multi-layer circuit board disclosed above can further include a buried hole 39 electrically connected to the blind holes (the connecting path is not shown in the diagram).
In FIG. 4B , the electrical pattern is formed on the top and the bottom surfaces of the core substrate. However, in practical application, the core substrate can have the electrical pattern on one surface only. Despite electrical pattern is formed on the top and the bottom conductive foils in FIG. 4B , in practical application, the electrical pattern can be formed on one of the conductive foils only.
Besides, if that the core substrate 19 of the deposited multi-layer circuit board has an electrical pattern formed on both the top surface and the bottom surface or on either of the top surface and bottom surface can alternatively be achieved by forming a blind hole in the manufacturing process of FIG. 3A and FIG. 3B in addition to the above manufacturing process of forming a through hole, an external electrical pattern electrically connected to the electrical pattern of the core substrate via the blind hole is subsequently formed on the outer surface. Referring to FIG. 5 , a third example of a circuit pattern formed on the surface of a deposited multi-layer circuit board is shown.
According to the manufacturing method of a multi-layer circuit board embedded with a passive component of the invention disclosed above, the metal protruding points are disposed on the conductive foils and the passive components can be directly mounted onto the metal protruding points via hot-pressing. Therefore, there is no need to consider the printing size of the passive component. Consequently, the complexity in the manufacturing process of forming the passive component is largely reduced, and the objects of simplifying the manufacturing process and enhancing electrical precision are achieved.
Therefore, the manufacturing method of a multi-layer circuit board embedded with a passive component according to the invention provides the user the manufacturing method of a multi-layer circuit board which can be applied to various manufacturing processes without having to consider the ability of the manufacturing process of the resistor or the capacitor as well as the difference between the original design and the manufactured product. The method according to the invention effectively simplifies the manufacturing process and the manufacturing costs as well.
While the invention has been described by way of example and in terms of a preferred embodiment, it is to be understood that the invention is not limited thereto. On the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures.
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A manufacturing method of a multi-layer circuit board embedded with a passive component includes the steps of: providing a conductive foil which has one or more pairs of metal protruding points; connecting a passive element to the corresponding metal protruding points; providing a board having a core substrate with organic insulation layer on a core substrate; stacking the conductive foil and the board, wherein the passive component is embedded in the organic insulation layer and patterning on the conductive foil.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This is a continuation of U.S. patent application Ser. No. 10/381,228, filed Jul. 23, 2003 which is the U.S. National Phase under 35 U.S.C. §371 of International Application PCT/JP2001/08234, filed Sep. 21, 2001, which claims priority to Japanese Patent Application No. 2000-291197, filed Sep. 25, 2000, and No. 2001-255554, filed Aug. 27, 2001. The disclosure of the foregoing applications is herein incorporated by reference in their entirety. The International Application was published under PCT Article 21(2) in a language other than English.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates to a non-coated gravure printing paper that provides excellent gravure printability through the achievement of better adhesion between the photogravure cylinder and the paper, thereby reducing the generation of speckles.
[0004] 2. Description of the Related Art
[0005] Gravure printing is a type of intaglio printing and therefore it requires a high degree of adhesion between the paper and the photogravure cylinder during printing. Poor adhesion between the paper and photogravure cylinder results in poor transfer of the ink, the likely result of which is the generation of so-called “speckles,” or small white spots, particularly in half-tone areas. The speckles invariably reduce the quality of the printed result. Good adhesion is achieved through the high smoothness and cushioning property of the paper. If the paper is smooth, it adheres more closely to the photogravure cylinder. A higher cushioning property allows the paper to deform under pressure during printing and thereby achieve better adhesion to the photogravure cylinder. These effects reduce the occurrence of speckles and thus improve printing quality.
[0006] Certain types of pulp and filler—two key ingredients in the production of paper—are selected to achieve higher smoothness and cushioning in a gravure printing paper. As for pulp, the content of mechanical pulp (such as groundwood pulp and refiner groundwood pulp) is maximized to increase the degree of cushioning. If chemical pulp materials must be used, ones having softer fibers are selected. To achieve a smoother surface, normally a gravure paper contains approximately 30% filler. This is more than the level found in offset printing papers, for example, where the filler content is generally 20% or less. Various other agents are added to the pulp and filler mixture, which is then made into paper. The obtained paper then undergoes a process of super-calendering to ensure high smoothness. While a filler consisting of fine, plate-shaped grains improves smoothness, the use of a filler containing grains that are too small in size increases the generation of speckles, although the smoothness does improve. Therefore, the filler content must be limited. Amid increasing environmental awareness throughout the public and industry of late, the use of recycled, ink-removed pulp is now favored over virgin pulp in both mechanical and chemical pulp applications. With chemical pulp it has become difficult to selectively source high-grade wood material from which flexible fibers can be obtained, or to procure chemical pulp made from such high-grade wood material. As a result it has become increasingly important to design quality gravure printing papers that generate less speckling, in addition to seeking the optimal blend of filler and pulp.
SUMMARY OF THE INVENTION
[0007] The purpose of this invention is to provide a gravure printing paper that reduces the generation of speckles by achieving better adhesion between the photogravure cylinder and the paper.
[0008] The inventors carried out extensive studies to identify ways of reducing speckles on paper during gravure printing, other than methods relating to pulp and filler selection. As a result it was found that speckling decreases when certain organic chemicals are added to the material mixture. This finding has in turn led to the invention presented here. Specifically, this invention provides a gravure printing paper that contains a substance or substances having the effect of inhibiting the binding between pulp fibers.
[0009] So-called “surfactant” having a hydrophobic group and a hydrophilic group have the effect of inhibiting the binding between pulp fibers, and therefore such agents (hereinafter referred to as “binding inhibitors”) may be used in this invention. However, a binding inhibitor need not be a surfactant as long as it inhibits the binding between fibers. Density reducers (or bulk-increasing agents), developed in recent years for the purpose of increasing paper bulk and currently available in the market, provide a degree of binding inhibition suitable to this invention. For example, higher alcohol containing ethylene and/or propylene oxide, which provides a polyhydric-alcohol type of nonionic surfactant, as defined in WO patent application No. 98/03730; higher fatty acid containing ethylene oxide as defined in Japanese Patent Application Laid-open No. 11-200284; and the ester of the reaction of polyhydric alcohol and fatty acid, ester of the reaction of polyhydric alcohol and fatty acid containing ethylene oxide, and fatty acid polyamide polyamine, as defined in Japanese Patent Application Laid-open No. 11-350380, can all be cited as examples of suitable binding inhibitors. The commercially available bulk-increasing chemicals include Sursol VL by BASF, Bayvolum P Liquid by Bayer, KB-08T, KB-08W, KB-10 and KB-115 by Kao and Reactopaque by Sansho. Two or more of these chemicals may be used in combination.
[0010] These binding inhibitors are not known to provide the effect of reducing speckles on gravure printing papers. The reason is not clear, but the following explanation offers a reasonable answer:
[0011] The aforementioned bulk-increasing agents or density reducers, when added to the paper material mixture as binding inhibitors, decrease the density of the paper and make the paper bulkier. However, gravure printing papers undergo a super-calendering process to achieve high smoothness, so that the resulting papers have neither higher bulk nor lower density. Nonetheless, because the binding inhibitors partially sever the bindings between pulp fibers and allow the fibers to move freely, when printing pressure is applied on the gravure paper the fibers move in response to the pressure and the paper adheres better to the photogravure cylinder. This facilitates the transfer of ink from the photogravure cylinder, in turn reducing the generation of speckles.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0012] This invention is basically a gravure printing paper that contains a substance or substances having the effect of inhibiting the binding between pulp fibers.
[0013] The gravure printing paper provided by this invention contains a substance or substances having the effect of inhibiting the binding between pulp fibers, wherein these substances, when added to 0.3 weight % of the bone-dry weight of pulp, will reduce the tensile strength of paper in the machine direction by 5 to 40% as measured per JIS P 8113, compared with the level when no binding inhibitors are added.
[0014] The gravure printing paper provided by this invention also contains 5 to 40% of ash as a filler in the aforementioned material composition.
[0015] The aforementioned characteristics of the gravure printing paper provided by this invention help achieve greater adhesion between the photogravure cylinder and the paper compared with other papers having similar density and smoothness, because the substance or substances contained in the paper have the effect of inhibiting the binding between pulp fibers. Therefore, the paper so produced provides an excellent benefit of reduced speckling.
[0016] The gravure printing paper provided by this invention reduces speckles by adding 0.01 to 10 weight %, or optimally 0.2 to 1.5 weight %, of binding inhibitor relative to the bone-dry weight of the pulp content of the gravure printing paper. If the binding inhibitor content is too high, the binding between fibers is inhibited more than is necessary. This will result in an excessive drop in paper strength, thereby making the paper prone to problems such as tearing. Therefore, a desirable binding inhibitor content is 0.3 weight % of the bone-dry weight of pulp, which should result in a 5 to 40% drop in the tensile strength under the tensile-strength drop test specified in the aforementioned standard.
[0017] The gravure printing paper provided by this invention uses chemical pulp (bleached or unbleached kraft pulp from softwood, bleached or unbleached kraft pulp from hardwood, etc.), mechanical pulp (groundwood pulp, thermomechanical pulp, chemi-thermomechanical pulp, etc.), or recycled, ink-removed pulp, wherein these material pulps may be used alone or in combination at arbitrary blending ratios.
[0018] The gravure printing paper provided by this invention may have a pH level that is in the acid, neutral or alkali range. It may use known fillers such as kaoline, talc, silica, white carbon, calcium carbonate, titanium oxide and synthetic resin filler. Ideally, fillers should be added to 5 to 40 weight % as the ash content in the paper, with an optimal content being in the range of 10 to 35 weight %. In this range of ash content the invention provides an ideal gravure printing paper offering improved smoothness and gloss. When the ash content exceeds 40 weight %, the paper strength will drop significantly.
[0019] Furthermore, the gravure printing paper provided by this invention may contain, if necessary, aluminum sulfate, sizing agent, paper strength enhancer, retention-aiding agent, coloring agent, dye, defoaming agent, and so on.
[0020] The gravure printing paper provided by this invention may be coated with surface-treatment agents for the purpose of adding a sizing property and increasing surface strength. The surface-treatment agents that may be used for this purpose are of the water-soluble polymer type. They include: starches such as normal starch, enzyme modified starch, thermo-chemically modified starch, oxidized starch, esterified starch, etherified starch and cationized starch; polyvinyl alcohols such as normal polyvinyl alcohol, fully saponified polyvinyl alcohol, partially saponified polyvinyl alcohol, carboxyl modified polyvinyl alcohol, silanol modified polyvinyl alcohol, cationic modified polyvinyl alcohol and terminal alkyl modified polyvinyl alcohol; polyacrylic amides such as normal polyacrylic amide, cationic polyacrylic amide, anionic polyacrylic amide and amphoteric polyacrylic amide; and celluloses such as carboxymethyl cellulose, hydroxyethyl cellulose and methyl cellulose. These materials may be used alone or in combination.
[0021] The binding inhibitor to be used in this invention may be selected from the substances mentioned earlier, through the use of tests such as the one specified below.
[0022] This test uses a pulp slurry of the target paper containing the testing substance by 0.3 weight % of the bone-dry weight of pulp. The mixture is made into paper using an oriented test paper machine (by Kumagaya Riki) operating at a speed of 900 rpm. The resultant paper is pressed and dried in accordance with the methods specified in JIS P 8209 to produce a test paper. In the test conducted by the inventors, a fan dryer was used to dry the paper at 50° C. for one hour. The test paper thus obtained is left in a temperature-controlled environment of 23° C. and a relative humidity of 50% for 24 hours, after which the tensile strength of the paper in the machine direction is measured in accordance with JIS P 8113. Substances that can reduce the tensile strength of paper in the machine direction are deemed suitable as binding inhibitors in this invention.
[0023] If the measured drop in tensile strength is very small, it means the applicable substance is less effective in reducing speckles and must be added in relatively greater volume. If the tensile strength drops substantially, just a small amount of that substance can effectively reduce the occurrence of speckling. So, although any substance can be used that reduces the tensile strength of paper, it is preferable to use those that can reduce the tensile strength by around 5 to 40% when added to 0.3 weight %.
[0024] The following is a detailed explanation of this invention using examples. However, the invention is not limited to the examples provided.
[0000] <Selection of Binding Inhibitor>
[0025] A one-% slurry was prepared by combining 30 weight-parts of bleached softwood kraft pulp (NBKP, CSF freeness 550 ml) and 70 weight-parts of refiner groundwood pulp (RGP). Each of the chemicals listed in Table 1 was added to 0.3 weight % of the bone-dry weight of pulp to create a paper material mixture. This paper material mixture was then processed into a paper with a grammage of 60 g/m 2 using an oriented test paper machine by Kumagaya Riki operating at a speed of 900 rpm. The paper thus obtained was pressed and dried in accordance with the methods specified in JIS P 8209.
[0026] The paper was dried in a fan dryer at 50° C. for one hour to obtain a test paper. The test paper was then left in a temperature-controlled environment of 23° C. and a relative humidity of 50% for 24 hours, after which the tensile strength of the paper in the machine direction was measured in accordance with JIS P 8113.
TABLE 1 Tensile Suitability as strength Drop in tensile binding Evaluated chemical (kN/m) strength (%) inhibitor KB-08W (Kao) 1.53 13.7 ◯ KB-110 (Kao) 1.50 14.8 ◯ Sursol VL (BASF) 1.56 9.8 ◯ Bayvolum P Liquid (Bayer) 1.59 9.7 ◯ Reactopaque (Sansho) 1.63 7.4 ◯ Isopropyl alcohol 1.73 1.7 Δ Starch 1.85 −5.1 X Casein 1.89 −7.4 X Polyethylene glycol 1.73 1.7 Δ Oleic acid 1.66 5.7 Δ Polyacrylic amide 2.00 −13.6 X No substance added 1.76 13
[0027] The above test indicated that the substances that reduce tensile strength by 6% or more are suitable as binding inhibitors in application to this invention, and that those resulting in a strength reduction of 10% or more are particularly suitable.
[0028] Next, gravure printing papers were created by adding KB-08W (Kao) and Sursol VL (BASF), these being the two agents that exhibited the best biding inhibition properties among the substances listed in Table 1.
EXAMPLE 1
[0029] A paper material mixture was prepared by combining 30 weight-parts of NBKP (CSF freeness 550 ml) and 70 weight-parts of RGP as the pulp content and 30 weight % of Indonesian kaoline as the ash content. KB-08W (by Kao) was added to this mixture as a binding inhibitor to 0.1 weight % of the bone-dry weight of pulp. The material mixture was then processed by an oriented test paper machine (by Kumagaya Riki) into a paper with a grammage of 60 g/m 2 .
[0030] During the paper-making process the pH of the material mixture was adjusted to 4.5 through the addition of aluminum sulfate. The resultant hand-made paper was subsequently processed by a test super-calender to obtain a gravure printing paper with an Oken's smoothness of 1000±100 seconds.
EXAMPLE 2
[0031] A gravure printing paper was obtained in the same manner as described in Example 1, except that KB-08W (by Kao) was added as a binding inhibitor to 0.4 weight % of the bone-dry weight of pulp.
EXAMPLE 3
[0032] A gravure printing paper was obtained in the same manner as described in Example 1, except that KB-08W (by Kao) was added as a binding inhibitor to 0.8 weight % of the bone-dry weight of pulp.
EXAMPLE 4
[0033] A gravure printing paper was obtained in the same manner as described in Example 1, except that Sursol VL (by BASF) was added as a binding inhibitor to 0.8 weight % of the bone-dry weight of pulp.
COMPARATIVE EXAMPLE 1
[0034] A gravure printing paper was obtained in the same manner and using super-calendering as described in Example 1, except that no binding inhibitor was added to the material mixture.
EXAMPLE 5
[0035] A gravure printing paper was obtained in the same manner and using super-calendering as described in Example 1, except that the material mixture was prepared by combining 20 weight-parts of newspaper DIP, 50 weight-parts of high-grade DIP and 30 weight-parts of RGP as the pulp content and 30 weight % of Indonesian kaoline as the ash content, to which KB-08W (by Kao) was added as a binding inhibitor to 0.8 weight % of the bone-dry weight of pulp.
COMPARATIVE EXAMPLE 2
[0036] A gravure printing paper was obtained in the same manner as described in Example 5, except that no binding inhibitor was added to the material mixture.
EXAMPLE 6
[0037] A paper material mixture was prepared by combining 30 weight-parts of NBKP (CSF freeness 550 ml) and 70 weight-parts of RGP as the pulp content and 30 weight % of a mixture of Indonesian kaoline and precipitated calcium carbonate blended at a ratio of 5:1 as the ash content. KB-08W (by Kao) was added to this material mixture as a binding inhibitor to 0.8 weight % of the bone-dry weight of pulp, and the mixture was made into a paper with a grammage of 60 g/m 2 using an oriented test paper machine. During the paper-making process the pH of the material mixture was adjusted to 7.5 through the addition of aluminum sulfate. The resultant hand-made paper was then processed by a test super-calender to obtain a gravure printing paper.
COMPARATIVE EXAMPLE 3
[0038] A gravure printing paper was obtained in the same manner and using super-calendering as described in Example 4, except that no binding inhibitor was added to the material mixture.
[0039] The following items were measured on the gravure printing papers obtained in the examples and comparative examples, the results of which are shown in Table 2.
[0040] (1) Speckling evaluation: Gravure printing was performed on a two-color gravure printability tester of the type used by the Printing Bureau (by Kumagaya Riki) at a printing speed of 40 m/minute under a printing pressure of 10 kg, and by using OGCT Process (indigo ink) by Toyo Ink (toluene-based, Zahn cup viscosity 10 seconds, 1:6 ratio of toluene to ink), after which the speckles were measured by visually counting the white dots (missing dots) in a 15-% half-tone area (30 mm×34.5 mm).
[0041] (2) Density: Measured in accordance with JIS P 8118
[0042] (3) Smoothness: Measured using an Oken type smoothness tester
[0043] (4) Tensile strength: The tensile strength of the paper in the machine direction was measured in accordance with JIS P 8113.
TABLE 2 Binding Tensile inhibitor Density Smoothness strength content (%) (g/m 2 ) (seconds) (kN/m) Speckles Example 1 0.1 0.99 950 1.28 90 Example 2 0.4 0.99 1029 1.15 53 Example 3 0.8 0.95 916 1.03 27 Example 4 0.8 0.97 920 0.95 32 Comparative 0 0.99 935 1.35 95 example 1 Example 5 0.8 1.00 1064 0.90 8 Comparative 0 1.01 1096 1.28 22 example 2 Example 6 0.8 0.95 1050 1.08 35 Comparative 0 0.96 980 1.42 110 example 3
[0044] From the results shown in Table 2, it became clear that the addition of binding inhibitors having the effect of inhibiting the binding between fibers and thereby reducing the tensile strength would reduce the number of speckles generated during gravure printing and therefore improve printing quality. These binding inhibitors, which act upon the bindings between fibers, are sometimes used as density reducers for the purpose of increasing paper bulk. However, gravure printing papers undergo a super-calendering process, and therefore the binding inhibitors do not substantially increase the bulk of such papers. In gravure printing papers the binding inhibitors do not serve as density reducers.
[0045] Additionally, although these binding inhibitors tend to increase smoothness during calendering, in the above tests all papers are assumed to have an equivalent smoothness.
[0046] The inventors therefore infer that the binding inhibitors reduce the occurrence of speckles on gravure printing papers not because they have density-reducing or smoothness-improving properties but because they allow the fibers to move more freely by inhibiting the binding between them and thus achieve better adhesion between the paper and the photogravure cylinder, thereby reducing the generation of speckles.
[0047] When the addition of a binding inhibitor only results in a five-% drop in tensile strength, as in the case of Example 1, speckling is not sufficiently suppressed. When the drop in tensile strength exceeds 10%, as shown by the results of examples 2 through 6, the number of speckles decreases substantially.
[0048] Furthermore, the speckle reduction effect of surface-active agents is evident, even after the pH of the paper material mixture is changed from the acid range of pH 4.5 (examples 1 through 5) to the alkali range of pH 7.5 (Example 6). In other words, these agents work effectively in both acid and alkali material mixtures without being affected by pH level.
INDUSTRIAL FIELD OF APPLICATION
[0049] This invention allows for the making of a gravure printing paper that provides an excellent benefit of reduced speckling, which is achieved by adding a substance or substances having the effect of inhibiting the binding between pulp fibers in the paper and thereby offering better adhesion between the photogravure cylinder and the paper.
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A method of manufacturing a gravure printing paper includes: providing a substance having an effect of inhibiting a binding between pulp fibers; preparing a mixture of pulp fibers and fillers; and adding the substance to the mixture; making a gravure printing paper using the substance-added mixture.
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BACKGROUND OF THE INVENTION
[0001] The present invention generally relates to articles of manufacture and methods of fabrication for mechanisms to relieve hoop stress in rotating bodies and, more specifically, to a J-slot modification to a rotating disk having integral cast blades such as those contained in a gas turbine engine.
[0002] Hoop stress is defined as a load measured in the direction of the circumference of a rotating body, the load being created by thermal gradients and centrifugal forces acting in a radial direction outwardly from the axis of rotation of the body. Such stress is particularly acute in the art of gas turbine engine design where the turbine disks may have integrally cast blades. Such turbine disks have been observed to develop fractures along the circumference of the disk during use.
[0003] A number of methods were devised to prevent such fractures. Initially a series of circumferential slots were fabricated into the outer edge of the disk and extending inwardly, the slots being produced using an electric discharge wire machine (EDM). The slots were observed to develop fractures at the inner end nearest the axis of rotation during use, so that a relief hole was drilled at the inner end of the slot to prevent further fracturing. The relief hole was observed to promote increased hot gas ingestion through the disk, so that a rivet or pin had to be inserted through the hole to block such gas ingestion.
[0004] This particular prior art hoop stress relief mechanism is shown in FIGS. 1 and 2 . According to FIG. 1 , a prior art hoop stress relief mechanism is shown as fabricated into a section of rotary body 100 with integral blades 110 . A slot 120 may be cut into the rotary body 100 radially from an outer rim 130 to intersect with a hole 140 . The slot 120 and hole 140 extend through the rotary body 100 so that the face 150 and the opposing face (not shown) of the rotary body 100 may be connected. A rivet 160 shown in phantom line may be inserted into the hole 140 and secured, so that hot gasses impacting face 150 may be prevented from flowing through the hole 140 to the opposing face of the rotary body 100 . Fabrication of the prior art hoop stress relief mechanism as shown may comprise the steps of drilling hole 140 through face 150 of the rotary body 100 , using an EDM to fabricate a continuous slot 120 from the outer rim 130 to the hole 140 , and deburring and reaming the hole 140 so that any gouges in the walls of hole 140 may be prevented from serving as sites for fractures in the rotary body 100 . Referring to FIG. 2 , a plurality of prior art slots 120 and holes 140 are fabricated between blades 110 around the circumference of the rotary body 100 so that hoop stress may be reduced and evenly distributed about the entire circumference of the outer rim 130 .
[0005] The method for fabricating this hoop stress relief mechanism involves a number of manufacturing steps. Referring to FIG. 1 , the hole 140 must be first drilled through the rotary body 100 and then reamed to remove any objectionable grooves or defects in the hole walls that formed in the drilling process. Next, the slot 120 must be machined from the outer rim 130 of the rotary body 100 to intersect the hole 140 . A rivet 160 must then be installed in the hole 140 to inhibit the flow of hot gasses through the hole 140 thus formed. These steps are used to fabricate the hole-and-slot configuration about the outer rim 130 of the rotary body 100 , and then the rotary body 100 is spun and balanced. The rivets 160 must then be inspected after the spinning operation to ensure that they are still properly seated and not deformed by the centrifugal force generated by the spin operation.
[0006] However, there are a number of problems associated with this mechanism: First, the method of fabricating the hoop stress relief mechanism involves a detailed sequence of operations that must be precisely executed. This sequence consists of drilling a hole of exact proportions through the disk, reaming the hole to eliminate ridges and grooves within the walls of its bore, cutting an EDM slot from the rim of the disk to the hole, inserting a rivet through the hole to prevent hot gas ingestion from an adjacent space, and inspecting the rivet for correct installation and placement. This sequence is labor intensive, time consuming, and exacting, and thus expensive.
[0007] Second, the rivet inserted into the drilled hole is frequently dislodged by vibration, thermal shock, or mechanical means during use. The rivet thus released can cause downstream damage within the turbine. Also, hot gases may subsequently leak through the turbine disk and reduce engine efficiency.
[0008] A third problem is that rivets have varying tolerances, so that when installed, they present a balancing problem. As the turbine rotates more rapidly, rivets that are mismatched as to size, weight, or placement along the circumference of the disk start producing unacceptable vibration. Too much vibration can cause the entire turbine to fail.
[0009] A fourth problem is that there are variations between different tools used to fabricate the holes and slots, which must be accounted for. For example, in a test, 24 holes were drilled with a 0.120″ drill, reamed with a 0.128″ reamer, and finally finished by four 0.1315″ reamers (6 holes each) to determine if tool variation was significant. An analysis of variance of the surface finish as a function of the block (final reamer) yielded a p-value <0.05, that is, the confidence is greater than 95% (p-value is a statement of probability where confidence=1−p-value). This test showed that the reamer/tool is significant and influences the surface finish. Mean surface finish for each tool ranged from 9.8 Ra to 25.9 Ra. Therefore, hole-drilling quality is limited by tool variation and is a problem in production fabrication. Current hole drilling processes impart detrimental flaws to the inner diameter surface of the rivet hole; these flaws can serve as sites at which fractures are initiated.
[0010] A number of similar methods have been found in the prior art to relieve hoop stress in various engine parts. U.S. Pat. No. 3,781,125 teaches the use of a keyhole shaped slotted portion in the outer shroud structure of a nozzle vane structure for a gas turbine engine. The keyhole shaped slot reduces stress due to larger temperature gradients. A threaded sealing member, instead of a rivet, is inserted into the keyhole to restrict gas flow. However, this application is made for a non-rotating shroud, and not for a turbine disk, and therefore does not experience the same problems as would be experienced by a rapidly rotating turbine disk.
[0011] U.S. Pat. No. 4,536,932 teaches a method of forming a turbine disk having integral blades from a plate shaped forging preform. A plurality of slots is formed between the integral blades, and the slots are then closed by the forging process. A rod or wire may be inserted at the base of each slot to increase the radius at the end of the slot. However, this process is amenable only to forging processes and does not address machining issues regarding the slot bases.
[0012] U.S. Pat. No. 5,071,313 teaches the use of T-shaped relief slots of a shroud body of a gas turbine engine. The relief slots are made in the outer portion of a non-rotating shroud for relief from thermal stress and not for centrifugal stress, where balancing and uniformity of the slots is a concern. The teaching is made for a non-rotating shroud, and not for a turbine disk, and therefore does not experience the same problems as would be experienced by a rapidly rotating turbine disk. The teaching does not discuss any considerations in the fabrication of the slots.
[0013] As can be seen, there is a need for a mechanism for relieving hoop stress in a rapidly rotating turbine disk structure, where the mechanism is simple to fabricate, does not allow excessive passage of hot gasses through the turbine disk, does not employ rivets which may become dislodged through use, and does not depend upon uniformity of the machining tools used to fabricate the mechanism.
SUMMARY OF THE INVENTION
[0014] In one aspect of the present invention, a hoop stress relief mechanism is provided for a solid rotary body with two faces and an outer rim. The mechanism comprises a slot extending inwardly a distance from the outer rim and providing communication between the first face and the second face, the slot having a first end at the outer rim and a second end, the slot also having a curved slot portion adjoining the second end.
[0015] In another aspect of the invention, a turbine disk with a hoop stress relief mechanism is provided, where the hoop stress relief mechanism comprises a plurality of J-shaped slots fabricated into the rim of the turbine disk.
[0016] In another aspect of the invention, a rotary body with an axis of rotation about which the rotary body rotates is provided, where the rotary body comprises a disk portion with an outer rim and a circular first and second faces; and a slot with a linear slot portion extending inwardly a distance from the outer rim and providing communication between the first face and the second face, the slot having a first end at the outer rim and a second end. The slot also has a curved slot portion adjoining the second end of the linear slot portion, the curved slot portion with a top surface and a bottom surface, the bottom surface being closer than the top surface to the axis of rotation of the rotary body.
[0017] In another aspect of the invention, a method of fabricating a hoop stress relief mechanism in a rotary body with an outer rim, two faces, and an axis of rotation is provided, the method comprising cutting of a plurality of J-shaped slots around the rim of a rotary body, where each slot penetrates the rotary body from face to face.
[0018] In still another aspect of the invention, an electric discharge wire machine may be used to cut the J-slots into the rim of the rotary body.
[0019] In yet another aspect of the invention, a method is provided for fabricating a slot in a rotary body having an outer rim, two faces, and an axis of rotation, where the slot has a linear slot portion extending from a first point at the outer rim to a second point situated inwardly a distance towards the axis of rotation, the slot further having curved slot portion continuing from the second point and curving back towards the outer rim to terminate at a third end, the slot allowing communication between the two faces. The method comprises the steps of cutting the slot in the rotary body with wire of an electric wire discharge machine by making a first pass from the first point to the third point to form the slot; removing a first portion of a recast layer formed along a bottom surface of the curved slot portion by moving the wire inwardly towards the axis of rotation by a first offset and moving the wire in a second pass from the third point to the second point, the second pass being parallel with the path of the first pass; removing a second portion of the recast layer formed along the bottom surface by moving the wire inwardly towards the axis of rotation by a second offset and moving the wire in a third pass from the second point to the third point, the third pass being parallel with the path of the second pass; and removing a third portion of the recast layer formed along the bottom surface by moving the wire inwardly towards the axis of rotation by a third offset and moving the wire in a fourth pass from the third point to the second point, the fourth pass being parallel with the path of the third pass; so that the total portion of the recast layer along the bottom surface that is removed equals the sum of the first, second, and third offsets.
[0020] These and other features, aspects and advantages of the present invention will become better understood with reference to the following drawings, description, and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 shows a front view of a turbine disk illustrating a single, prior art hoop stress relief mechanism fabricated therein;
[0022] FIG. 2 shows a front view of a turbine disk with a plurality of prior art hoop stress relief mechanisms as they are fabricated along the rim of the turbine disk;
[0023] FIG. 3A shows a front view of a turbine disk illustrating a J-slot hoop stress relief mechanism, according to an embodiment of the invention;
[0024] FIG. 3B shows a side perspective view of a turbine disk illustrating the placement of the J-slot hoop stress relief mechanism with relationship to the blades of a turbine disk, according to an embodiment of the invention;
[0025] FIG. 4 shows a side perspective view of turbine disk with a plurality of hoop stress relief mechanisms as they are fabricated along the rim of the turbine disk, according to an embodiment of the invention;
[0026] FIG. 5 shows a cross section of a rotary body with a tapered rim angle as defined by blade design, according to an embodiment of the invention;
[0027] FIG. 6 shows a top perspective view of the rim of a rotary body, illustrating the placement of a J-slot between two adjacent blades, according to an embodiment of the invention;
[0028] FIG. 7 shows the geometry of a representative J-slot with the orientation of the slot angle; and
[0029] FIG. 8 shows a representative path taken by an EDM wire in fabricating the J-slot, according to an embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0030] The following detailed description is of the best currently contemplated modes of carrying out the invention. The description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the invention, since the scope of the invention is best defined by the appended claims.
[0031] The invention provides an innovative mechanism for relieving fractures along the rim of a rotating body that may be caused by hoop stress forces. The innovative mechanism may be a slot extending inwardly from the rim in a generally radial direction and terminating in a curved portion. The slot may extend through the disk of the rotating body. Fabricating such a stress relieving slot in the circumferential rim of a disk may be inexpensive since it does not involve as many steps as the rivet mechanism described previously. There is minimal leakage through the disk and the slot may be essentially free from any hole drilling surface anomalies that may be caused by the drilling process.
[0032] Referring now to the drawings wherein like reference numerals are used throughout the various views to designate like parts and, more particularly, to FIGS. 3A and 3B , according to these figures, a segment 300 of a rotary body is shown, where the segment 300 has integral blades 110 cast with a disk portion 320 . A hoop stress relief mechanism 330 is shown between the blades 110 of the segment 300 and passing through the disk portion 320 to exit on a front face 350 and a rear face 360 of the disk portion 320 . Referring more particularly to FIG. 3A for detail, the relief mechanism 330 may be comprised of a J-slot 370 extending inwardly from a rim 130 of the segment 300 . A linear slot portion 372 of the J-slot 370 may extend a distance before curving back upon itself in a curved slot portion 375 to form the J-slot 370 . A plurality of J-slots 370 may be spaced along the circumference of a turbine disk as shown in FIG. 4 to provide stress relief for both thermal and centrifugal forces that would tend to cause fractures about the rim 130 . The ends of the curved slot portions 375 may extend in either the direction of rotation of the rotary body 100 or the opposite direction.
[0033] The geometry of a typical J-slot 370 and its relationship to a rotary body 100 , such as a turbine disk, is shown in FIGS. 5, 6 , and 7 . According to FIGS. 5 and 6 , the stacking axes 510 of the rotary body 100 may exist in a plane perpendicular to its center of rotation and between its faces 150 , such that the rotary body 100 may be balanced along each side of the stacking plane 510 . Blades 110 may be integrally cast with the rotary body 100 such that they may extend radially from the rim 130 and the center of rotation of rotary body 100 . It should be noted that the rim 130 is not necessarily perpendicular to the stacking axis 510 but may taper towards one face 150 or the other by a disk rim taper angle 520 . The J-slot curved surface 375 may also be tapered with angle 530 from one face 150 to the other face 150 of the rotary body 100 . Each blade 110 may have a fillet 111 at its base where it flares to meet the rim 130 without an abrupt change in the contour between the blade 110 and the rim 130 .
[0034] As shown in FIG. 6 , a J-slot 370 may be fabricated between two adjacent blades 110 . The J-slot 370 may be fabricated at a slash angle 610 , which is defined as the angle of the J-slot 370 from a plane orthogonal to the plane of the stacking axes 510 drawn through the center of rotation of the rotary body 100 . The J-slot 370 should be constrained to avoid cutting through the fillet 111 of an adjacent blade 110 , which may weaken the blade structure. In order to position the J-slot 370 between two adjacent blades 110 without making contact with the fillet 111 of either blade 110 , it may be necessary to fabricate the J-slot 370 with a non-zero slash angle 610 . Ideally, the leading edge offset 630 and the trailing edge offset 620 from one blade 110 and the blade convex surface offset 640 from the other blade 110 should all be equal; but design and balancing considerations may require empirical adjustment of these values.
[0035] Referring to FIG. 7 , the geometry of a typical J-slot 370 is shown. Disk rim radius 710 may be defined as the distance from the center of rotation of the rotary disk to the rim 130 taken along the stacking plane 510 . The slot bottom radius 720 may be defined as the distance from the center of rotation of the rotary disk 100 to the bottom 780 of the J-slot 370 taken along the stacking plane 510 . The minor diameter of the J-slot 370 may be defined as two times the radial distance 730 from the bottom 780 of the J-slot 370 to a point 795 which is the point of tangency between the curved slot portion 375 and a radial line extending outward from the center of rotation of the rotary disk 100 . The major diameter 740 of the J-slot curved portion 370 is shown in FIG. 7 . Point 790 may be defined as the intersection of the slot rim radius 710 drawn through the bottom 780 of the J-slot 370 and circumferential line drawn through point 795 . The linear slot portion 372 may be inclined at a slot angle 770 with respect to the rim 130 , defined as the angle between the linear slot portion 372 and the disk rim radius 710 drawn through point 790 .
[0036] The gap 760 between the slot tip 796 and the linear slot portion 372 may advantageously be of a distance of 0.050 inch or greater to ensure product quality and producibility. The tip angle 765 may be defined by a first line drawn between point 790 and the slot tip 796 and a second line tangent to a circle having its center at the axis of rotation and drawn through point 790 . A tip angle 765 in a range between 20° to 80° may provide acceptable stress relief without failure of the J-slot 370 .
[0037] Using EDM technology, an inventive method for fabricating the J-slot 370 in the rim of a rotary body may use the EDM to remove material in the rotary body according to a predetermined pattern to form the J-slot 370 . Referring to FIG. 8 , it has been found that an EDM produces a recast layer 875 , 876 , 877 along the sides of a slot cut by the EDM. The recast layer 875 , 876 , 877 may be defined as the surface that results when an EDM has been used to cut away material. The EDM may generate sufficient heat in cutting away material that the surface along its path may have ridges, waves, and other irregularities. It has been found that in the art of turbine design, a rough surface may have a lower mean time before failure, because the hoop stress produced by rotation is concentrated by such irregularities; a smooth surface may thus have a longer service life. Therefore, it is desirable that the inner surfaces along a path made by an EDM have a smooth, uniform recast layer 875 , 876 , 877 . The extent of the recast layer 875 , 876 , 877 may be influenced by the speed of the EDM cut, the angle at which the cut is made, and the amount of heat generated thereby. It has been further found that the surface 860 ( FIG. 8 ) of the slot at the bottom of the curved slot portion 375 may be subjected to more hoop stress than the surface 870 along the linear slot portion 372 of the J-slot nearer the rim 130 , and therefore it may be desirable for surface 860 at the bottom portion of the J-slot nearest the axis of rotation of the rotary body 100 to be fairly smooth, i.e. have a smooth or minimal recast layer 876 . The recast layer 877 along top portion of the curved slot portion 375 may not be subjected to the same stress, and its thickness and uniformity may be immaterial.
[0038] The recast layer 876 along the bottom of the curved slot portion 375 may be smoothed by various methods that may be within the scope of the invention. However, a sequence of back-and-forth passes of the EDM as indicated in FIG. 8 may be advantageously provided by the inventive method to smooth the bottom of the curved slot portion 375 . A first pass 820 may be made as a rough cut through the linear slot portion 372 and the curved slot portion 375 , which may define the general shape of the J-slot. A second pass 830 may be made by reversing the direction of travel of the wire of the EDM as indicated and offsetting the path slightly in a direction normal to surface of the curved slot portion 372 , with the second pass 830 generally following the path of the first pass 820 through the curved slot portion 375 . The second pass 830 may be seen as removing a first portion of the recast layer 876 equal in thickness to the first offset of the path of the second pass 830 . When the wire, while traveling along the path of the second pass 830 , arrives at the junction of the linear slot portion 372 and the curved slot portion 375 , the wire may again be reversed and offset towards the center of the rotary body 100 by a second amount to follow the indicated path of the third pass 840 , thus removing a second portion of the recast layer 876 equal in thickness to the second offset of the path of the third pass 840 . Finally, the wire may again be reversed and offset by a third amount to follow the indicated path of the fourth pass 850 , thus removing a third portion of the recast layer 876 equal in thickness to the third offset of the path of the fourth pass 850 . Thus, the recast layer 876 created by the first pass 820 may be smoothed along the surface 860 of the curved slot portion 375 nearest to the center of the rotary body 100 by removing an amount of material from the recast layer 876 equal to the sum of the first, second, and third offsets.
[0039] For example, it has been found through experimentation that a typical J-slot 370 may be fabricated according to the inventive method by making four passes on a Sodick machine using 0.008″ diameter wire. The second, third, and fourth passes may be offset by amounts of 0.00051″, 0.00063″, and 0.00004″, respectively. Other EDMs having different wire diameters and different offset values for the various passes could be used without departing from the scope of the invention. Current EDM technology can yield a recast thickness of less than 0.0002″ and a 32 Ra finish, resulting in an EDM wire J-slot 370 free from detrimental manufacturing flaws. This process may be repeated for selected locations around the perimeter of the rotary body to form a plurality of J-slots 370 around the rim of the rotary body as shown in FIG. 4 . However, the number of slots may be equal to or less than the number of blades. Then the rotary body may be balanced to ensure that any manufacturing variations between different J-slots 370 are compensated for. The rotary body may also be spun up to speed to ensure a proper balance. It can be readily seen that use of the inventive method may eliminate three labor intensive manufacturing steps; where these steps are (1) hole drilling and reaming, (2) installation of rivets/pins, and (3) inspection of rivets after spinning (approx. 3.8 hrs/part). This in turn may eliminate the potential damage to the rotor surfaces during the installation and removal of rivets/pins. Furthermore, bin stock providing pins and/or rivets 160 used to reduce leakage through the holes 140 can be eliminated.
[0040] As shown in FIG. 8 , the geometry of the J-slot 370 may be varied to maximize the stress relieving characteristics of the mechanism. Both the slash angle 610 and the slot angle 770 may be varied to keep hoop stress to which the J-slot 370 is subjected below a design threshold. These angles may be highly dependent upon the targeted service life for the rotary body 100 , the blade geometry at the rim of the rotary body 100 and the number of blades 110 , the material from which the rotary body 100 is manufactured, and the bending stress to which the rotary body 100 is subjected.
[0041] Also, other inventive configurations of the J-slot 370 may be conceived without departing from the scope of the invention. For example, a double J-slot 370 may be fabricated with two curved slot portions 375 each extending in opposite directions from the linear slot portion 372 , in a shape much like an inverted “T” with the tips bent back towards the central shaft.
[0042] An inventive hoop stress relief mechanism and a method for its fabrication have thus been disclosed. The relief mechanism provided by the invention may be a series of J-shaped slots that have been machined about the rim of a rotary body, each slot penetrating the rotary body from face to face. The J-slots may be fabricated into the rim of the rotary body by a electric discharge wire machine, thus reducing the number of time consuming steps required by the prior art method of drilling and reaming holes and installing rivets therein.
[0043] It should be understood, of course, that the foregoing description of the invention relates to preferred embodiments of the invention and that modifications may be made without departing from the spirit and scope of the invention as set forth in the following claims.
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A hoop stress relief mechanism is disclosed for use on a rotary body to relieve stress caused by both thermal and centrifugal forces. The mechanism may consist of a J-shaped slot cut from the outer rim of the rotary body a distance inwardly toward the axis of rotation, the slot having a curve in its inward end that curves back towards the outer rim. The J-shaped slot may extend through the rotary body to join its two faces. The J-shaped slot may be fabricated by an electric discharge wire machine. The electric discharge wire machine may make multiple passes in order to smooth the bottom surface of the curved slot portion.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an infrared curable ink composition for a color filter, and more particularly, an infrared curable ink composition for a color filter including a melamine compound and an epoxy compound.
[0003] The present application claims priority to Korean Patent Application Nos. 10-2009-0063160 filed on Jul. 10, 2009, 10-2009-0063161 filed on Jul. 10, 2009 and 10-2010-0065873 filed on Jul. 8, 2010, the disclosure of which is incorporated herein by reference in its entirety.
[0004] 2. Description of the Related Art
[0005] Display device is essential for the age of information society and multimedia, and recently, it is made to be small and thin in size and light in weight, thereby being applied to a variety of fields. With the advance of semiconductor technology, the concerns about flat panel display (FPD) applicable to various fields are growing, and there have been developed many different types of flat panel display, including liquid crystal display (LCD), plasma display panel (PDP), organic electroluminiscent display (OELD) or the like.
[0006] In the liquid crystal display device, an electric voltage is applied to vary the molecular arrangement of the liquid crystal layer, and therefore light transmittance is controlled to display desired information. To develop color, the liquid crystal display device is provided with color filters of the three colors including red, green and blue. When light transmittance is controlled by altering the liquid crystal arrangement, light passing through each color filter is controlled, such a way that, color is developed.
[0007] Typically, color filters are located on a glass substrate, and three types of the color filters should be regularly and elaborately distributed in a specific shape. As the method of forming three types of the color filter, a printing method, an electrodeposition method, a photolithography method, and an ink-jet printing method are reported.
[0008] First, the photolithography method is as follows. Pixel regions are defined on a transparent substrate, and black matrices for shielding a light source between the pixel regions are formed on the transparent substrate. Next, a color resist is coated to cover the entire surface of the substrate including the black matrices, and a color filter pattern of a specific color (for example, a red color filter pattern) is formed by exposing the color resist using a mask. Subsequently, a red color filter is formed on the glass substrate through development and curing processes. Sequentially, other color filters are also formed by repeatedly performing the processes. However, this method is problematic in that its efficiency is reduced by large amounts of loss of materials and the process is complicated.
[0009] Second, the ink-jet printing method is a method of directly printing color filter materials, and has advantages that the process can be simplified, loss of materials can be prevented, and the process cost can be also reduced without the need of photolithography process. In the ink-jet printing method, a black matrix pattern is formed on the glass substrate, and the formed pixel space is filled with ink including a pigment. The volatile solvent contained in the ink is evaporated through the process of curing ink (baking process), and a color filter is formed by cross-linking process.
[0010] The process of manufacturing a color filter is exposed to a lot of chemicals, and thus the formed color filter is required to have chemical resistance during the process. The chemical resistance is determined by the cross-linking density of color filter ink film, and thus the process of curing ink applied on the glass substrate is a very important process during the manufacture of the color filter.
[0011] In the conventional process of curing ink, that is, baking process, a post-baking process employing a thermal convection method was used. In this process, the substrate is loaded in a chamber, and heated by thermal convection method, so that cross-linking reaction in the ink occurs and the solvent is volatilized. That is, ink for a color filter is jetted on the glass substrate, and then heating is performed at a predetermined temperature for solvent evaporation, thereby stabilizing the ink on the substrate. However, the post-baking process employing the thermal convection method is problematic in that it must employ a gas becoming a convection mediator within the chamber and requires a significantly long time in order to cure the color filter film. During the baking process, various foreign materials are generated on the substrate, and in particular, during the post-baking process employing the thermal convection method, the possibility of generating foreign materials increases due to a long baking time. Thus, the process has drawbacks that much time and operating costs are required for the production process, resulting in low efficiency.
[0012] Therefore, instead of the post-baking process employing the thermal convection method, alternative processes have been developed, and Korean Patent Laid-Open Publication No. 10-2008-0083944 discloses an IR Curing device capable of performing the post-baking process by infrared radiation with high heat transfer.
[0013] Unlike the conventional post-baking process using the thermal convection method, the infrared curing process employs infrared rays having a high output and an excellent heating characteristic. In particular, it is characterized by a rapid curing performance, thereby reducing production time and costs, and improving, production yield. Thanks to a short curing time, the generation of foreign materials on the substrate can be also reduced during the curing process.
[0014] Unlike the post-baking process using the thermal convection method, the infrared curing process is performed for a short curing time (approximately 1 to 10 min) at high temperature (250° C. or higher). Therefore, the ink for a color filter used in this process is required to have physical and chemical characteristics different from those used in the post-baking process using the thermal convection method.
[0015] In general, the ink for a color filter is characterized in that it has a higher pigment concentration and higher viscosity due to high solid content, compared to the photoresist (PR) for a color filter. The chemical resistance of the ink for a color filter is determined by the strength and cross-linking density of ink film. Because of its higher pigment content, a relatively small amount of binder and cross-linking agent are contained, leading to deterioration in the chemical resistance of the ink film. The deterioration in the chemical resistance generates problems that pigments contained in the color filter film are melted out upon post-processing such as alignment film formation during the production of color filter, leading to deterioration in color development or influence on liquid crystal operation. In particular, a red ink is problematically weak in chemical resistance.
[0016] Accordingly, the ingredients contained in the ink for a color filter should have excellent chemical resistance, and maintain high cross-linking density even at a small amount, and not deteriorate pigment dispersibility when added to the ink. In addition, those possessing an extremely high viscosity should not be used, because they deteriorate the jetting property. The ink for a color filter used in the infrared curing process has a very short curing time. Thus, if the cross-linking process is not performed rapidly, its chemical resistance is deteriorated. Therefore, the ink for a color filter is required to have a rapid cross-linking characteristic.
[0017] The conventional ink compositions for a color filter are described in Japanese Patent Laid-Open Publication Nos. 2009-74010 and 1995-196968. However, these ink compositions for a color filter are not used for the infrared curing process, and not suitable for the 3 minute curing process such as infrared curing process.
[0018] Accordingly, there is a need for an ink composition for a color filter having excellent chemical resistance, in which it can be sufficiently cured for a short period of time as in the infrared curing process. Therefore, the present inventors have made studies to develop an ink composition for a color filter, which is suitable for the infrared curing process and has excellent chemical resistance, thereby completing the present invention.
SUMMARY OF THE INVENTION
[0019] The present invention provides an infrared curable ink composition for a color filter showing excellent chemical resistance through an infrared curing process for a short curing time.
[0020] Further, the present invention provides a color filter having excellent chemical resistance, which is produced by the infrared curable ink composition for a color filter.
[0021] Further, the present invention provides a liquid crystal display device including the color filter.
[0022] According to an aspect of the present invention, there is provided an infrared curable ink composition for a color filter, including one or more melamine compounds represented by the following Formula 1; and an epoxy compound.
[0023] [Formula 1]
[0000]
[0024] wherein R 1 , R 2 , R 3 , R 4 , R 5 and R 6 are each independently selected from the group consisting of functional groups including hydrogen, a hydroxy group, a C 1 -C 6 alkyl group, a C 1 -C 6 alkoxy group, a C 1 -C 6 carboxyl group, a C 1 -C 6 alkoxy methyl group, a C 1 -C 6 alcohol group, a phenyl group, an acryl group and a vinyl group, and at least one of R 1 to R 6 is a C 1 -C 6 alcohol group or a C 1 - C 6 alkoxy methyl group.
[0025] As used herein, the term “infrared curing” or “infrared curing process” means that infrared rays having a high output and an excellent heating characteristic are used to cure the ink by evaporating a solvent contained in the ink composition for a color filter, and the process is performed for a short curing time (approximately 100 sec to 5 min) unlike the conventional post-baking process (approximately 30 min to 60 min).
[0026] As used herein, the term “ink for a color filter” refers to an ink for the production of a color filter that is used in liquid crystal display device. When the ink for a color filter is jetted on a substrate by an ink-jet method, and then cured, a color filter is formed on the substrate.
[0027] The epoxy compound used in the present invention is a compound that is used in the ink composition for a color filter having excellent chemical resistance, and characterized in that it is rapidly reacted and cured with a melamine compound during the infrared curing process.
[0028] From the viewpoint that the curing reaction occurs rapidly, any epoxy compound can be used without limitation, as long as it contains two or more epoxy groups in the molecule, for example, one or more selected from the group consisting of bisphenol A-type epoxy, bisphenol F-type epoxy, brominated bisphenol A-type epoxy, bisphenol S-type epoxy, diphenyl ether-type epoxy, hydroquinone-type epoxy, naphthalene-type epoxy, biphenyl-type epoxy, fluorene-type epoxy, novolac-type epoxy, tris hydroxy phenyl methane-type epoxy, trifunctional-type epoxy, tetraphenylethane-type epoxy, dicyclo pentadiene phenol-type epoxy, hydrogenated bisphenol A-type epoxy, bisphenol A-containing nuclear polyol-type epoxy, polypropylene glycol-type epoxy, glycidyl ester-type epoxy, glycidyl amine-type epoxy, linear aliphatic epoxy, alicylic epoxy, and heterocyclic epoxy. Preferably, the epoxy compound is novolac-type epoxy, for example, may be one or more epoxy compounds selected from the group consisting of phenol novolac-type epoxy, cresol novolac-type epoxy, BPA-type novolac and substituted epoxy. More preferably, the epoxy compound is phenol novolac-type epoxy, such as EPPN-502H and EPPN-501H (trade name), but is not limited thereto.
[0029] The epoxy compound is preferably contained in an amount of 0.5 to 10% by weight, and more preferably 1 to 8% by weight, based on the total weight of the ink composition for a color filter. If the epoxy content is less than 0.5% by weight, the amount of the epoxy compound is not sufficient to deteriorate the cross-linking density. If the epoxy content is more than 10% .by weight, storage stability of the ink composition may deteriorate.
[0030] The melamine compound used in the present invention is a compound that is used in the ink composition for a color filter having excellent chemical resistance, and even if a small amount thereof is used, high cross-linking density is maintained, pigment dispersibility is not deteriorated, and it is rapidly reacted and cured with the epoxy compound during the infrared curing process.
[0031] From the viewpoint that the curing reaction occurs rapidly, the melamine compound may be a melamine compound represented by Formula 1. More preferably, in the definition of Formula 1, R 1 , R 2 , R 3 , R 4 , R 5 and R 6 may be each independently selected from the group consisting of hydrogen, a hydroxy group, a C 1 ˜C 6 alkyl group, a C 1 ˜C 6 alkoxy group, a methylalcohol group, a C 1 ˜C 6 alkoxy methyl group and an acryl group.
[0032] Preferably, the melamine compound may be a compound represented by the following Formula 2 or 3.
[0000]
[0033] wherein R 7 , R 8 , R 9 , R 10 , R 11 , R 12 , R 13 , R 14 and R 15 may be each independently selected from the group consisting of hydrogen and a C 1 ˜C 6 alkyl group.
[0034] More preferably, the melamine compound may be selected from the group consisting of methoxymethyl melamine, ethoxymethyl melamine, and butoxymethyl melamine. The melamine compound may be readily purchased from commercially available source. A methylol derivative may be obtained by condensation of melamine with formalin, and methylol ether derivatives thereof may be obtained by reacting the methylol derivative thereof with various alcohols by the known method. More specifically, the melamine compound may be exemplified by Cymel 303, Cymel 350, Cymel 3745, Cymel MM-100, Cymel 370, Cymel 373, Cymel 3749, Cymel 327, Cymel 323, Cymel 325, Cymel 328, Cymel 385, Cymel 1116, Cymel 1130, Cymel 1133, Cymel 1161, Cymel 1168, Cymel 3020, Cymel 615, Cymel 683, Cymel 688, Cymel MB-11-B, Cymel MB-14-B, and Cymel 1158 (trade names) manufactured by Cytec Industries Inc.
[0035] The melamine compound is contained in an amount of 0.5 to 10% by weight, and more preferably 1 to 8% by weight, based on the total weight of the ink composition for a color filter. If the melamine content is less than 0.5% by weight, the cross-linking density is not sufficient to deteriorate the chemical resistance. If the melamine content is more than 10% by weight, the film strength is reduced.
[0036] The epoxy compound and the melamine compound are rapidly cross-linked and cured during the infrared curing process, and therefore, an ink film having excellent chemical resistance can be obtained. From this viewpoint, a molar ratio of the melamine compound and the epoxy compound is preferably 0.5 to 4:1. If the ratio of the melamine compound to the epoxy compound is not within the range, a sufficient film strength is not ensured, or improvement in the chemical resistance can be reduced.
[0037] Meanwhile, the infrared curable ink composition for a color filter according to the present invention may further include a pigment; a pigment dispersant; and a solvent.
[0038] As used herein, the term “pigment” refers material that functions as a coloring agent to express the color of liquid crystal display device.
[0039] Two or more types of organic or inorganic pigments can be mixed with each other, and used as the pigment, but the preferred pigment is the organic pigment having excellent color developing property and heat resistance.
[0040] Hereinbelow, specific examples of the pigment used in the ink composition of the present invention are represented by the color index number.
[0041] Examples of the red pigment may include C. I. Pigment Red 7, 14, 41, 48:1, 48:2, 48:3, 48:4, 81:1, 81:2, 81:3, 81:4, 146, 168, 177, 178, 179, 184, 185, 187, 200, 202, 208, 210, 246, 254, 255, 264, 270, 272, 279 or the like, and among them, C. I. Pigment Red 177 and 254 are preferred in terms of high brightness and high contrast.
[0042] Examples of the green pigment may include C. I. Pigment Green 7, 10, 36, 37, 58 or the like, and among them, C. I. Pigment Green 7, 36, and 58 are preferred in terms of high brightness and high contrast.
[0043] Examples of the yellow pigment may include C. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 10, 12, 13, 14, 15, 16, 17, 18, 24, 31, 32, 34, 35, 35:1, 36, 36:1, 37, 37:1, 40, 42, 43, 53, 55, 6300·61, 62, 63, 65, 73, 74, 77, 81, 83, 93, 94, 95, 97, 98, 100, 101, 104, 106, 108, 109, 110, 113, 114, 115, 116, 117, 118, 119, 120, 123, 126, 127, 128, 129, 138, 139, 147, 150, 151, 152, 153, 154, 155, 156, 161, 162, 164, 166, 167, 168, 169, 170, 171, 1572, 173, 174, 175, 176, 177, 179, 180, 181, 182, 185, 187, 188, 193, 194, 198, 199, 213, 214 or the like, and among them, C. I. Pigment Yellow 138, 139, and 150 are preferred in terms of high brightness and high contrast.
[0044] Examples of the blue pigment may include C. I. Pigment Blue 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, 22, 60, 64 or the like.
[0045] Examples of the violet pigment may include Violet 23 or the like.
[0046] Examples of the cyan pigment may include C. I. Pigment Blue 15:3 or a mixture of C. I. Pigment Blue 15:3 and C. I. Pigment Green 7.
[0047] Examples of the magenta pigment may include mixtures of C. I. Pigment Red 81, 81:1, 81:2, 81:3, 81:4, 122, 192, 202, 207, or 209, and C. I. Pigment Violet 19.
[0048] In the composition of the present invention, a colorant may be used in combination, in addition to the pigment. The examples of the colorant may include dye, natural colorant or the like.
[0049] The pigment is preferably contained in an amount of 5 to 20% by weight, based on the total weight of the ink composition for a color filter. If the pigment content is less than 5% by weight, it is difficult to obtain the desired color reproduction range. If the pigment content is more than 20% by weight, the curing property is remarkably deteriorated, and adhesion property is reduced.
[0050] As used herein, the term “pigment dispersant” refers to a material that uniformly and finely disperses a pigment in the ink composition for a color filter so as to improve the performance of liquid crystal display device upon color development.
[0051] Non-limiting preferred examples of the dispersant include surfactants such as cationic, anionic, nonionic, cationic silicone-based, and fluorine-based surfactants, or polymer surfactants (polymer dispersant). For example, polyethylene imine-based, urethane resin-based, acryl resin-based or polyester-based polymer dispersants may be used.
[0052] The pigment dispersant is preferably contained in an amount of 1 to 15% by weight, and more preferably 2 to 10% by weight, based on the total weight of the ink composition for a color filter. If the content of pigment dispersant is less than 1% by weight, the pigment dispersibility may be not sufficient. If the content of pigment dispersant is more than 15% by weight, the viscosity of ink is increased to deteriorate the jetting property.
[0053] As used herein, the term “solvent” refers to a material that functions to disperse the pigment in the ink composition for a color filter and facilitates to jet (discharge) the ink without drying the ink in a nozzle. The solvent to be used in the present invention contains 70% or more, and preferably 80% or more of a solvent having a high boiling point of 180° C. or higher.
[0054] As a main solvent, the solvent having a boiling point of 200° C. or higher prevents the end of the nozzle from drying to facilitate jetting (discharge) of the ink. It is preferable that the solvent has a boiling point of 200° C. to 300° C. and a vapor pressure of 0.5 mmHg or less at room temperature.
[0055] Non-limiting examples thereof may include one or more selected from the group consisting of ethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol ethyl ether acetate, dipropylene glycol propyl ether acetate, dipropylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monohexyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethylether, triethylene glycol monobutylether, triethylene glycol monopropyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monomethyl ether and tripropylene glycol monobutyl ether, but are not limited thereto.
[0056] In addition, in term of solubility, pigment dispersibility and convenience of coating film formation, solvents having a low boiling point (200° C. or lower) may be used in combination. That is, the solvent of the present invention may be mixed with the solvent having a low boiling point, as long as it does not deteriorate advantages of the solvent having a high boiling point and low viscosity.
[0057] Specific examples of the solvents having a low boiling point may include glycol ether such as diethylene glycol dimethylether, diethylene glycol diethylether; ketones such as methylethylketone, cyclohexanone, and 4-hydroxy-4-methyl-2- pentanone; esters such as methyl, ethyl, propyl and butyl esters of acetic acid, ethyl and methyl esters of 2-hydroxypropionic acid, ethyl ester of 2-hydroxy-2-methylpropionic acid, methyl, ethyl, and butyl esters of hydroxyacetic acid, methyl lactate, ethyl lactate, propyl lactate, butyl lactate, methyl, ethyl, propyl, and butyl esters of methoxyacetic acid, methyl, ethyl, propyl, and butyl esters of propoxyacetic acid, methyl, ethyl, propyl, and butyl esters of butoxyacetic acid, methyl, ethyl, propyl, and butyl esters of 2-methoxypropionic acid, methyl, ethyl, propyl, and butyl esters of 2-ethoxypropionic acid, methyl, ethyl, propyl, and butyl esters of 2-butoxypropionic acid, methyl, ethyl, propyl, and butyl esters of 3-methoxypropane, methyl, ethyl, propyl, and butyl esters of 3-ethoxypropionic acid, methyl, ethyl, propyl, and butyl esters of 3-butoxypropionic acid; propylene glycol methyl ether acetate, ethylene glycol monomethyl ether acetate, ethylene glycol ethyl ether acetate, propylene glycol monobutyl ether acetate, ethyl iso-butyl ether, ethyl ethoxy propionate, methoxy propanol, butoxy propanol, 2-butoxy ethanol, butyl acetate, 1-butoxy-2-propanol, cyclohexanone, dimethyl ketone, methyl butyl ketone and methyl hexyl ketone.
[0058] The solvent may be contained in the ink composition for a color filter at a residual amount, and preferably in an amount of 65 to 85% by weight, based on the total weight of ink composition for a color filter. In this connection, if the content of the solvent is less than 65% by weight, the ink viscosity is increased to remarkably reduce the jetting property. If the content of the solvent is more than 85% by weight, the solid content is lowered increase the number of ink drops necessary for filling pixels in order to produce the same thickness.
[0059] In the present invention, the ink composition preferably has a viscosity within the range of 10 to 15 cP, and more preferably within the range of 12 to 14 cP. The ink composition having the viscosity within the above range can be most readily jetted.
[0060] Further, the infrared curable ink composition for a color filter may further include a binder.
[0061] The binder used in the present invention is a material that improves interface and adhesion properties and readily forms a color filter ink film, and any binder can be used without limitation as long as it does not deteriorate the intrinsic property of the ink composition for a color filter.
[0062] The binder polymer may be prepared by copolymerization of one or two selected from the group consisting of styrene, chloro styrene, α-methyl styrene, vinyl toluene, 2-ethylhexyl(meth)acrylate, methyl(meth)acrylate, ethyl(meth)acrylate, butyl(meth)acrylate, benzyl(meth)acrylate, glycidyl(meth)acrylate, dimethylaminoethyl(meth)acrylate, isobutyl(meth)acrylate, t-butyl(meth)acrylate, cyclohexyl(meth)acrylate, dicyclopentanyl(meth)acrylate, isobornyl(meth)acrylate, 2-phenoxyethyl(meth)acrylate, tetrahydrofurfuryl(meth)acrylate, hydroxyethyl(meth)acrylate, 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, 2-hydroxy-3-chloropropyl(meth)acrylate, 2-hydroxybutyl(meth)acrylate, 4-hydroxybutyl(meth)acrylate, dimethylaminomethyl(meth)acrylate, diethylamino(meth)acrylate, acyloctyloxy-2-hydroxypropyl(meth)acrylate, ethylhexyl acrylate, 2-methoxyethyl(meth)acrylate, 3-methoxybutyl(meth)acrylate, butoxyethyl(meth)acrylate, ethoxydiethyleneglycol(meth)acrylate, methoxytriethyleneglycol(meth)acrylate, methoxytripropyleneglycol(meth)acrylate, methoxypolyethyleneglycol(meth)acrylate, phenoxydiethyleneglycol(meth)acrylate, p-nonylphenoxypolyethyleneglycol(meth)acrylate, p-nonylphenoxypolypropyleneglycol(meth)acrylate, tetrafluoropropyl(meth)acrylate, hexafluoroisopropyl(meth)acrylate, octafluoropentyl(meth)acrylate, heptadecafluorodecyl(meth)acrylate, tribromophenyl(meth)acrylate, methyl α-hydroxymethyl acrylate, ethyl α-hydroxymethyl acrylate, propyl α-hydroxymethyl acrylate, butyl α-hydroxymethyl acrylate, N-phenylmaleimide, N-(4-chlorophenyl)maleimide, methacrylic acid, maleic acid, and itaconic acid. The binder polymers having an average molecular weight from 4000 to 50000 are preferred.
[0063] The binder is preferably contained in an amount of 8% by weight or less, based on the total weight of the ink composition for a color filter. If the binder content is more than 8% by weight, the ink viscosity is problematically increased.
[0064] Further, the ink composition for a color filter according to the present invention may further include other additives in addition to the above described ingredients. Examples of the additives may include one or more of a plasticizer, an adhesion promoter, a filler, a defoaming agent, a dispersion aid, an anticoagulant, and a surfactant. These additives are preferably contained in an amount of 0.01 to 3% by weight, based on the total weight of the ink composition for a color filter.
[0065] Meanwhile, the ink composition of the present invention does not include a photoacid generator, a photoinitiator, an acid catalyst, a thermal initiator or the like. Since the ink composition of the present invention is a composition suitable for the infrared curing process that is performed at high temperature for a short time, the curing reaction occurs within a short period of time by the melamine compound and the epoxy compound to obtain an ink film having excellent chemical resistance, even though the ink composition does not include the above ingredients.
[0066] According to an another aspect of the present invention, there is provided a color filter manufactured by using the infrared curable ink composition for a color filter according to the present invention. The color filter may be manufactured in any method, as long as the method employs the ink composition for a color filter. Preferably, the color filter may be manufactured by jetting and curing the ink composition for a color filter on the substrate, on which patterns are formed by the ink jet method.
[0067] A material of the substrate is not particularly limited, but a glass substrate, a plastic substrate, or a flexible substrate may be used, and preferably a glass substrate having strong heat resistance.
[0068] The curing process of the packed ink composition is preferably performed in accordance with the infrared curing process a temperature of 240 to 300° C. If the temperature is less than 240° C., evaporation and curing of the solvent are not sufficient so as to reduce the film strength and chemical resistance. If the temperature is more than 300° C., an excessive reduction in the volume of pixel area deteriorates adhesion to the substrate and accuracy.
[0069] According to a still another aspect of the present invention, there is provided a liquid crystal display device including the color filter according to the present invention. The liquid crystal display device may be used in a TV-LCD or monitor-LCD depending on the use, and exemplified by TN LCD (TWISTED NEMATIC LCD), STN LCD (SUPER TWISTED NEMATIC LCD), FSTN LCD (FILM SUPER TWIST NEMATICS LCD), DSTN LCD DSTN (DOUBLE LAYER SUPER TWISTED NEMATIC LCD), IPS LCD (IN-PLANE SWITCHING LCD), VA LCD (VERTICAL ALIGNMENT LCD), PVA LCD (PATTERNED VERTICAL ALIGNMENT LCD), depending on the operation method and its structure, but is not limited thereto as long as it is used in any field in need of the color filter. The liquid crystal display device according to the present invention may be manufactured by the conventional technique known in the art, except for using the infrared curable ink composition for a color filter of the present invention.
[0070] The infrared curable ink composition for a color filter according to the present invention is characterized in that it can be cured for a very short period of time compared to the known ink composition for a color filter and used to produce a color filter having excellent chemical resistance even though the curing process is performed for a short time. Therefore, it has the following characteristics.
[0071] First, the production time for the color filter can be greatly, shortened. The conventional baking process employing a thermal convection method requires a curing time of approximately 30 min or longer. However, since the infrared curable ink composition for a color filter according to the present invention can be rapidly cured, it is suitable for the infrared curing process, thereby remarkably simplifying the production process and shortening the time required for color filter production.
[0072] Second, thanks to the short curing time, the generation of foreign materials on the substrate can be reduced during the curing process. Because the ink composition for a color filter of the present invention can be used in the infrared curing process, and cured for a short time, the generation of foreign materials on the substrate can be reduced during the curing process. Thus, process and costs required for the removal of the foreign materials can be greatly reduced, thereby improving the process efficiency.
[0073] Third, since the ink composition for a color filter according to the present invention is cured for a short time, it has excellent chemical resistance. Therefore, even though it is exposed to chemicals, color difference between each color filter, loss of ink film, or various defectives generated by contamination due to the color filter film can be reduced.
[0074] The infrared curable ink composition for a color filter including a melamine compound and an epoxy compound according to the present invention can be cured for a short time, thereby being used in the infrared curing process and simplifying the production process and shortening the time required for color filter production. In addition, thanks to the short curing time, the generation of foreign materials can be reduced during the curing process, and the color filter produced by the ink composition according to the present invention has excellent chemical resistance and heat resistance, thereby being applied to various electronic devices such as liquid crystal display device.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0075] Hereinafter, the preferred Examples are provided for better understanding. However, these Examples are for illustrative purposes only, and the invention is not intended to be limited by these Examples.
Preparation Example 1
Preparation of Binder Resin 1
[0076] 1.6 parts by weight of V65 (manufactured by Wako pure chemicals) as a thermal initiator was dissolved in a solvent (BCA, Diethylene glycol monobutyl ether acetate) and then benzylmethacrylate/methacrylic acid were added at a molar ratio of 68/32, and reacted in a reaction vessel under nitrogen atmosphere at 65° C. for 7.5 hrs.
[0077] The copolymer solution obtained was put in a flask equipped with a stirrer, and glycidylmethacrylate was added thereto, and further reacted at 110° C. for 6 hrs to prepare a thermosetting copolymer. The prepared binder resin had an acid value of 46 KOHmg/g and a weight average molecular weight of 8,300 g/mol.
Preparation Example 2
Preparation of Binder Resin 2
[0078] 1.6 parts by weight of V65 as a thermal initiator was dissolved in a solvent (BCA) and then benzylmethacrylate/methylmethacrylate/methacrylic acid/hydroxyethylmethacrylate were added at a molar ratio of 30/40/10/20, and reacted in a reaction vessel under nitrogen atmosphere at 65° C. for 7.5 hrs to prepare a binder resin 2. The prepared binder resin had an acid value of 55 KOHmg/g and a weight average molecular weight of 8,700 g/mol.
Example
Preparation of Infrared Curable Ink Composition for a Color Filter
[0079] The infrared curable ink composition for a color filter according to the present invention was prepared by the following method. In particular, the infrared curable ink composition for a color filter according to the present invention includes a melamine compound and an epoxy compound. % by weight described in the following is % by weight to the final ink composition for a color filter produced.
Production of Example 1
[0080] 2.8% by weight of red pigment (R254), 5.7% by weight of red pigment (R177), 1.8% by weight of yellow pigment (Y150), 5.8% by weight of pigment dispersant, and 4.3% by weight of melamine compound (Cymel 303; Cytec Industries Inc.) were first mixed together to prepare a pigment dispersion. 1.6% by weight of melamine compound (Cymel 303; Cytec Industries Inc.), 2.7% by weight of epoxy compound (EPR174(Epikote828)), and 75.3% by weight of solvent (BCA) were further added, and mixed to prepare an infrared curable ink composition for a color filter.
Production of Example 2
[0081] 2.8% by weight of red pigment (R254), 5.5% by weight of red pigment (R177), 1.8% by weight of yellow pigment (Y150), 5.6% by weight of pigment dispersant, and 4.2% by weight of melamine compound (Cymel 303; Cytec Industries Inc.) were first mixed together to prepare a pigment dispersion. 0.6% by weight of the binder resin of Preparation Example 2, 1.6% by weight of melamine compound (Cymel 303; Cytec Industries Inc.), 2.7% by weight of epoxy compound (EPR174(Epikote828)), and 75.2% by weight of solvent (BCA) were further added, and mixed to prepare an infrared curable ink composition for a color filter.
Production of Example 3
[0082] 2.8% by weight of red pigment (R254), 5.7% by weight of red pigment (R177), 1.8% by weight of yellow pigment (Y150), 5.8% by weight of pigment dispersant, and 2.3% by weight of melamine compound (Cymel 327; Cytec Industries Inc.) were first mixed together to prepare a pigment dispersion. 3.8% by weight of melamine compound (Cymel 327; Cytec Industries Inc.), 2.5% by weight of epoxy compound (EPR174(Epikote828)), and 75.3% by weight of solvent (BCA) were further added, and mixed to prepare an infrared curable ink composition for a color filter.
Production of Example 4
[0083] 2.8% by weight of red pigment (R254), 5.7% by weight of red pigment (R177), 1.8% by weight of yellow pigment (Y150), 5.8% by weight of pigment dispersant, and 2.3% by weight of melamine compound (Cymel 327; Cytec Industries Inc.) were first mixed together to prepare a pigment dispersion. 3.8% by weight of melamine compound (Cymel 1130; Cytec Industries Inc.), 2.5% by weight of epoxy compound (EPPN-502H, manufactured by NIPPON KAYAKU Co.), and 75.3% by weight of solvent (BCA) were further added, and mixed to prepare an infrared curable ink composition for a color filter.
Production of Example 5
[0084] 2.8% by weight of red pigment (R254), 5.7% by weight of red pigment (R177), 1.8% by weight of yellow pigment (Y150), 5.8% by weight of pigment dispersant, and 2.3% by weight of melamine compound (Cymel 327; Cytec Industries Inc.) were first mixed together to prepare a pigment dispersion. 3.8% by weight of melamine compound (Cymel 1130; Cytec Industries Inc.), 2.5% by weight of epoxy compound (NC-7300L, manufactured by NIPPON KAYAKU Co.), and 75.3% by weight of solvent (BCA) were further added, and mixed to prepare an infrared curable ink composition for a color filter.
Production of Example 6
[0085] 2.8% by weight of red pigment (R254), 5.7% by weight of red pigment (R177), 1.8% by weight of yellow pigment (Y150), 5.8% by weight of pigment dispersant, and 2.3% by weight of melamine compound (Cymel 327; Cytec Industries Inc.) were first mixed together to prepare a pigment dispersion. 3.8% by weight of melamine compound (Cymel 1130; Cytec Industries Inc.), 2.5% by weight of epoxy compound (EPPN-501H, manufactured by NIPPON KAYAKU Co.), and 75.3% by weight of solvent (BCA) were further added, and mixed to prepare an infrared curable ink composition for a color filter.
Production of Comparative Example 1
[0086] 2.8% by weight of red pigment (R254), 5.7% by weight of red pigment (R177), 1.8% by weight of yellow pigment (Y150), 5.8% by weight of pigment dispersant, and 4.3% by weight of melamine compound (Cymel 303; Cytec Industries Inc.) were first mixed together to prepare a pigment dispersion. 1.3% by weight of the binder resin of Preparation Example 1, 2.5% by weight of polymerizable monomer (DPHA), 0.5% by weight of thermal initiator, and 75.3% by weight of solvent (BCA) were further added, and mixed to prepare an infrared curable ink composition for a color filter.
Production of Comparative Example 2
[0087] 2.8% by weight of red pigment (R254), 5.7% by weight of red pigment (R177), 1.8% by weight of yellow pigment (Y150), 5.8% by weight of pigment dispersant, and 4.3% by weight of melamine compound (Cymel 303; Cytec Industries Inc.) were first mixed together to prepare a pigment dispersion. 4.3% by weight of melamine compound (Cymel 303; Cytec Industries Inc.) and 75.3% by weight of solvent (BCA) were further added, and mixed to prepare an infrared curable ink composition for a color filter.
Production of Comparative Example 3
[0088] 2.8% by weight of red pigment (R254), 5.7% by weight of red pigment (R177), 1.8% by weight of yellow pigment (Y150), and 5.8% by weight of pigment dispersant were first mixed together to prepare a pigment dispersion. 2.4% by weight of the binder resin of Preparation Example 1, 5.7% by weight of polymerizable monomer (DPHA), 0.5% by weight of thermal initiator, and 75.3% by weight of solvent (BCA) were further added, and mixed to prepare an infrared curable ink composition for a color filter.
Production of Comparative Example 4
[0089] 2.8% by weight of red pigment (R254), 5.7% by weight of red pigment (R177), 1.8% by weight of yellow pigment (Y150), 5.8% by weight of pigment dispersant, and 4.3% by weight of melamine compound (Cymel 303; Cytec Industries Inc.) were first mixed together to prepare a pigment dispersion. 1.1% by weight of the binder resin of Preparation Example 1, 3.2% by weight of melamine compound (Cymel 303; Cytec Industries Inc.) and 75.3% by weight of solvent (BCA) were further added, and mixed to prepare an infrared curable ink composition for a color filter.
Production of Comparative Example 5
[0090] An ink composition for a color filter was prepared in the same manner as in Example 4. However, convection oven curing was performed using the above composition in the following Experimental Examples, instead of performing the infrared curing.
Production of Comparative Example 6
[0091] 2.8% by weight of red pigment (R254), 5.7% by weight of red pigment (R177), 1.8% by weight of yellow pigment (Y150), and 5.8% by weight of pigment dispersant were first mixed together to prepare a pigment dispersion. 3% by weight of melamine compound (Cymel 1130; Cytec Industries Inc.), 12% by weight of epoxy compound (EPPN-502H, manufactured by NIPPON KAYAKU Co.), and 68.9% by weight of solvent (BCA) were further added, and mixed to prepare an infrared curable ink composition for a color filter. (molar ratio of melamine compound:epoxy compound=0.25:1)
Production of Comparative Example 7
[0092] 2.8% by weight of red pigment (R254), 5.7% by weight of red pigment (R177), 1.8% by weight of yellow pigment (Y150), and 5.8% by weight of pigment dispersant were first mixed together to prepare a pigment dispersion. 12% by weight of melamine compound (Cymel 1130; Cytec Industries Inc.), 2.5% by weight of epoxy compound (EPPN-502H, manufactured by NIPPON KAYAKU Co.), and 69.4% by weight of solvent (BCA) were further added, and mixed to prepare an infrared curable ink composition for a color filter. (molar ratio of melamine compound:epoxy compound=4.8:1)
[0093] The compositions of Examples and Comparative Examples are summarized in the following Table 1. The values in parenthesis mean % by weight to the final ink composition for a color filter.
[0000]
TABLE 1
Non-
Ink
Pigment
Melamine
Epoxy
epoxy
Solvent
composition
Pigment a)
dispersant
compound
compound
compound
Binder
(BCA)
Additive
Example 1
(2.8)
(5.8)
Cymel 303
EPR174(Epikote828)
(75.3)
(5.7)
(5.9)
(2.7)
(1.8)
Example 2
(2.8)
(5.6)
Cymel 303
EPR174(Epikote828)
Preparation
(75.2)
(5.7)
(5.8)
(2.7)
Example 2
(1.8)
(0.6)
Example 3
(2.8)
(5.8)
Cymel 327
EPR174(Epikote828)
(75.3)
(5.7)
(6.1)
(2.5)
(1.8)
Example 4
(2.8)
(5.8)
Cymel 327
EPPN-502H
(75.3)
(5.7)
(2.3)
(2.5)
(1.8)
Cymel
1130
(3.8)
Example 5
(2.8)
(5.8)
Cymel 327
NC-7300L
(75.3)
(5.7)
(2.3)
(2.5)
(1.8)
Cymel
1130
(3.8)
Example 6
(2.8)
(5.8)
Cymel 327
EPPN-501H
(75.3)
(5.7)
(2.3)
(2.5)
(1.8)
Cymel
1130
(3.8)
Comparative
(2.8)
(5.8)
Cymel 303
DPHA
Preparation
(75.3)
thermal
Example 1
(5.7)
(4.3)
(2.5)
Example 1
initiator
(1.8)
(1.3)
(0.5)
Comparative
(2.8)
(5.8)
Cymel 303
(75.3)
Example 2
(5.7)
(8.6)
(1.8)
Comparative
(2.8)
(5.8)
DPHA
Preparation
(75.3)
thermal
Example 3
(5.7)
(5.7)
Example 1
initiator
(1.8)
(2.4)
(0.5)
Comparative
(2.8)
(5.8)
Cymel 303
Preparation
(75.3)
Example 4
(5.7)
(7.5)
Example 1
(1.8)
(1.1)
Comparative
(2.8)
(5.8)
Cymel 327
EPPN-502H
(75.3)
Example 5
(5.7)
(2.3)
(2.5)
(1.8)
Cymel
1130
(3.8)
Comparative
(2.8)
(5.8)
Cymel
EPPN-502H
(68.9)
Example 6
(5.7)
1130
(12)
(1.8)
(3)
Comparative
(2.8)
(5.8)
Cymel
EPPN-502H
(69.4)
Example 7
(5.7)
1130
(2.5)
(1.8)
(12)
a) pigment represents R254, R177, and Y150 and their content is shown in order
Experimental Example 1
Evaluation of Chemical Resistance
[0094] To evaluate chemical resistance of the compositions prepared in Examples and Comparative Examples, the following experiment was performed.
[0095] The infrared curable ink compositions for a color filter prepared in Examples 1-6 and the ink compositions for a color filter of Comparative Examples 1-4 and 6-7 were applied to washed glasses, and pre-baked at 90° C. for 3 min, and then, the infrared curing (IR curing) process was performed for 115 sec (conditions: temperature was raised for 90 sec and maintained at 260° C. for 25 sec) to completely cure the ink. The ink composition for a color filter of Comparative Example 5 was subjected to convection oven curing at 220 to 230 ° C. for 2 min, instead of performing the infrared curing.
[0096] The obtained ink coating film (thickness: 1 to 2 μm) was immersed in a 45° C. NMP (N-Methyl Pyrrolidinone) solution for 1 hr, and then color difference (ΔEab) before and after immersion in the NMP solution was evaluated (color difference (ΔEab)<3 considered as in good condition), and the results are shown in the following Table 2.
[0000]
TABLE 2
Chemical
Ink composition
resistance (ΔEab)
Evaluation
Example 1
1.05
∘
Example 2
1.44
∘
Example 3
1.41
∘
Example 4
1.16
∘
Example 5
1.06
∘
Example 6
1.21
∘
Comparative Example 1
3.53
x
Comparative Example 2
3.07
x
Comparative Example 3
45.25
x
Comparative Example 4
4.67
x
Comparative Example 5
30.6
x
Comparative Example 6
Jetting impracticable
Comparative Example 7
Jetting impracticable
* Color difference (ΔEab) <3: ∘, Color difference (ΔEab) ≧3: x
[0097] As shown in Table 2, a slight color difference was observed in the infrared curable ink composition for a color filter of the present invention before and after immersion in the NMP solution, indicating that the ink composition of the present invention was cured sufficiently even for a short curing time, and thus can be used in the infrared curing process.
[0098] Meanwhile, a great color difference was observed in the ink compositions of Comparative Examples before and after immersion in the NMP solution, indicating that the ink compositions were not sufficiently cured by the rapid curing process, thereby reducing chemical resistance, unlike the conventional process by a thermal convection method. In particular, since the ink compositions for a color filter of Comparative Examples 6 and 7 had very high viscosity and bad storage stability, it was not possible to perform the jetting itself.
Experimental Example 2
Evaluation of Chemical Resistance Under High Temperature Condition (Heat Resistance)
[0099] To evaluate the chemical resistance, that is, heat resistance of the compositions of Examples 1-6 and Comparative Examples 1-7 under high temperature condition, the following experiment was performed.
[0100] The evaluation of the chemical resistance was performed in the same manner as in Experimental Example 1, except that the evaluation of the chemical resistance was performed under the immersion conditions of 80° C. for 40 min. The results are shown in Table 3. In Table 3, color difference less than 20, preferably 5 to 20, was considered as, in good condition
[0000]
TABLE 3
Chemical
Ink composition
resistance (ΔEab)
Evaluation
Example 1
16.47
∘
Example 2
17.11
∘
Example 3
13.81
∘
Example 4
9.45
∘
Example 5
17.94
∘
Example 6
9.52
∘
Comparative Example 1
not measurable
Comparative Example 2
not measurable
Comparative Example 3
not measurable
Comparative Example 4
not measurable
Comparative Example 5
103
x
Comparative Example 6
not measurable
Comparative Example 7
not measurable
* Color difference (ΔEab) <20: ∘, Color difference (ΔEab) ≧20: x
[0101] As shown in Table 3, the compositions of Examples using the melamine and epoxy compounds showed good chemical resistance at a high temperature of 80° C. In particular, the compositions of Examples 4 and 6 using novolac-type epoxy were found to have good chemical resistance.
[0102] Meanwhile, in the compositions of Comparative Examples, excluding that of Comparative Example 5, the ink film was melted out, and thus color difference was not measurable. A great color difference was observed in the composition of Comparative Example 5 before and after immersion in the NMP solution.
[0103] Taken together, the infrared curable ink composition for a color filter including melamine and epoxy compounds the present invention did not show a great color difference before and after immersion in the NMP solution under the curing conditions of high temperature and short time, indicating that the ink composition of the present invention was sufficiently cured by the infrared curing process at high temperature for a short time, and thus can suitably used in the infrared curing process. In particular, when using novolac-type epoxy as an epoxy compound, more excellent chemical resistance and heat resistance can be ensured. When the temperature of the infrared curing process is increased, the curing process can be performed for a shorter curing time. Thefore, from the viewpoint of reducing the production process, it can be seen that the ink composition of the present invention has
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The present invention relates to an infrared curable ink composition for a color filter. The ink composition according to the present invention includes a melamine compound and an epoxy compound, and thus can be cured for a short time, thereby being used in the infrared curing process, and reducing the production process and time required for the color filter production. In addition, the color filter produced by the ink composition according to the present invention has excellent chemical resistance and heat resistance, thereby being applied to various electronic devices such as liquid crystal display device.
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BACKGROUND OF THE INVENTION
The present invention relates to a system for the incineration of combustible gases in a reaction chamber wherein the gas is introduced into the reactor in a low pressure laminar flow state. More particularly, the invention relates to a method of incinerating waste gases from industrial processes by substantially converting them to relatively non-polluting, low temperature products of combustion. Still more particularly, the invention relates to a means for combusting pyrophoric silane waste products from epitaxial or other reactors which are used in the manufacture of semiconductors.
Methods of incinerating gaseous waste products have been known heretofore. Generally, such have suffered from the disadvantage that substantially complete combustion of the vent gas has not been achieved, thereby allowing the release of pollutants to the atmosphere, or products of combustion result at unacceptably high temperatures. Also, the release of pyrophoric materials such as silanes is very dangerous since they may spontaneously ignite uncontrolledly when mixed with air. Further, apparatus for carrying out prior methods for incinerating streams of combustible vent gas are often relatively expensive to install and operate. In these cases, the waste gases are introduced into a reaction chamber under relatively high pressure either via pumping or nozzle means in order to intimately mix with incoming air for subsequent ignition. Such high pressure systems are not suitable for some industrial processes. For example, in the manufacture of semiconductors, silane gas along with other components such as phosphine and arsine are conducted over silicon wafers for reaction therewith. In order to assure a highly uniform wafer, the reactants are introduced at about atmospheric pressure or very slightly above atmospheric pressure which is sufficient only to insure flow into the reactor. Waste gases from this reactor exit at essentially the same rate as the inflow. Inflow is naturally laminar to assure uniformity of production and therefore waste gases exit through appropriate piping in a laminar fashion. Should the exit flow be subsequently constricted, for example via a nozzle, to raise the velocity of exiting gases to induce turbulent flow for mixture with air, then an unacceptable back pressure would be induced upstream in the silane/silicon wafer reactor. Furthermore, it is theorized, that when turbulent silane gas is admixed with air it is atomized thus forming a protective invisible bubble of silicon dioxide around molecular silane. When this bubble is burst in uncontrolled surroundings, it reacts with air explosively with much resultant property damage or even death. The present invention either effectively prevents bubble formation or shears these bubbles open in a controlled combustion chamber and ignites the silane gas to form relatively harmless and non-polluting oxides of silicon.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a cross-sectioned elevational view of the apparatus of the present invention.
SUMMARY OF THE INVENTION
The invention provides an apparatus for incinerating combustible gases which comprises:
(a) a first pipe member having open entrance and exit end portions and an inlet opening through the wall thereof intermediate said end portions;
(b) a second pipe member having first and second ends, said first end being fixed about said inlet to provide a means of ingress and egress between said pipe members, said second end being substantially closed to its surroundings;
(c) ignition means disposed within said second pipe portion;
(d) means for conducting a laminar flow of at least one combustible gas into said second pipe portion; and
(e) means for turbulently flowing a stream of a gas capable of supporting combustion into the entrance end of said first pipe member, then centrifugally swirling said turbulent gas flow into and out of said second pipe member through said inlet, and then discharging said turbulent gas flow through the exit end of said first pipe member.
The invention further provides a method for incinerating combustible gases which comprises:
(a) providing an apparatus comprising
(i) a first pipe member having open entrance and exit end portions and an inlet opening through the wall thereof intermediate said end portions; and
(ii) a second pipe member having first and second ends, said first end being fixed about said inlet to provide a means of ingress and egress between said pipe members, said second end being substantially closed to its surroundings; and
(iii) ignition means disposed within said second pipe portion;
(b) conducting a laminar flow of at least one combustible gas into said second pipe portion; and
(c) turbulently flowing a stream of a gas capable of supporting combustion into the entrance end of said first pipe member, then centrifugally swirling said turbulent gas flow into and out of said second pipe member through said inlet while causing said combustible gas to ignite in said second pipe member; and then discharging said gas flow through the exit end of said first pipe member.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The invention provides an apparatus for incinerating combustible gases, particularly gases which are pyrophoric. The invention is particularly suitable for burning a mixture of hydrogen and silane gases which also contains waste dopants such as arsine and phosphine which are useful in the manufacture of semiconductor devices.
The preferred apparatus is shown in FIG. 1. It comprises a first pipe member 2 having open entrance and exit ends 4 and 6 respectively. Between these ends is an inlet 8. Attached about this inlet is a second pipe member 10 which is open on the end which attaches to the aforementioned inlet 8. In the preferred embodiment the pipe members are perpendicularly attached by suit means such as welding. Second pipe member 10 is substantially closed to its surroundings at its opposite end 12. In one form of the invention this closure is achieved by means of a cover plate 14 which is suitably attached, for example by bolts, which are not shown. Both pipes and cover plates should be made of drawn carbon steel. Attached through a side wall of the second pipe member is a means of ignition 16. In the preferred embodiment this means is one or more spark plugs, preferably having a platinum tip which catalyzes the ignition of the fuel gases. Such fuel gases are supplied by flowing them into the second pipe via appropriate tubing 18. Means 20 and 22 may also be provided to detect ignition and temperature respectively in the apparatus. Such flame and temperature detectors are well known to the skilled artisan.
In operation, entrance end 4 supplies a source of a turbulently flowing gas capable of supporting combustion. Usually this is merely atmospheric air, although any oxygen source is also suitable. In the preferred embodiment, exit end 6 is connected via flange 24 to a standard commercial scrubber 32. The scrubber turbulently draws the air through the pipe 2 from entrance 4 via a sucking action. The fuel gases preferably flow into pipe 10 through tubes 18 in a very low pressure laminar fashion In semiconductor manufacturing activities doped silane gases, for example in epitaxial reactors, must flow into the reactor very gently and under a very low pressure to assure uniformity of the process. Pressures are normally held at slightly above atmospheric pressure so as to provide a very small amount of forward flow. A typical forward pressure is one atmosphere ±1/2 inch of water. Therefore, in order to maintain this constant pressure in the reactor, waste gases must flow into tube 18 at essentially the same pressure in order to avoid back pressure upstream. In order to assure a uniform mixture, fuel gases in laminar flow through take 18 are mixed with turbulently flowing air which enters through opening 4. It has been found that when high velocity air flowing through pipe 2 reaches inlet 8, it meets with low velocity gases in pipe 2. A portion of the air therefore enters inlet 8, hits the side wall of pipe 10 at point 26 and centrifugally swirls in the direction of arrow 28. In a preferred embodiment, the gases which flow through tubes 18 are at least combustible and are usually pyrophoric. Since pyrophoric gases ignite spontaneously when contacted by air a separate ignition source might not normally seem necessary. However, to assure combustion, the invention provides ignition means 16 as added reliability for the apparatus. Furthermore, when merely combustible gases such as hydrogen are used, an ignition source certainly is desired, if not necessary. To add further reliability to the apparatus, the ignition spark plug 16 may be provided with a platinum tip to catalyze ignition when hydrogen gas is used. Still more preferably at least two such spark plugs are desired to add an extra measure of reliability of ignition.
Without intending to be bound by a particular theory, silane gases, while known to be pyrophoric and hence ignite in the presence of air, do not always ignite immediately on such exposure. It is believed that when silane gas is exposed to oxygen in the air, certain oxides of silicon are produced which form a protective bubble. Silane gas then fills this bubble much like a balloon. This protective bubble prevents oxygen from reaching the silane continuously for ignition. When this enlarged bubble eventually breaks, a large amount of silane is exposed to oxygen precipitously and a violent explosion may occur. By means of the present invention, it is believed that the centrifugal swirling action of the turbulently flowing oxygen shears the silane bubbles and permits essentially complete combustion before any explosive build up can occur. In carrying out combustion, ignition and burning are conducted primarily within pipe member 10 where a swirling flame is induced. The flame is then directed down pipe 2 in the direction of arrow 28. In the preferred embodiment, a baffle 30 is provided as a flame director in order to guide the produced flame down along the longitudinal axis of pipe 2 and thus to avoid the inside wall of pipe 2 to the extent possible. In operation the flame actually does not travel much beyond the end of the baffle and the long pipe length as well as an excess supply of incoming air serves as a heat sink to cool down the temperature of exhaust gases to a considerable extent. In fact the gases passing through exit 6 are preferably less than one hundred degrees Celsius and can certainly be safely treated by a commercial scrubber.
As further safety features, the supply of fuel gas from tubes 18 may be regulated by a series of sensors. These may include a flame sensor within pipe 10, a temperature sensor within pipe 22 and a seismic disturbance sensor. For example, fuel flow maybe cut off if the flame is extinguished, the temperature rises outside desirable limits or seismic activity is noted. Each of these sensor types are well known in the art. Such sensors may cause the appropriate electrical signals to travel to a relay which closes off or reduces fuel gas flow. The overall system may be provided with an appropriate control panel which includes temperature monitoring, flame detection, fuel and air flow measurement, alarms, start, stop, and reset controls and the like.
While there have been described herein what are at present considered preferred embodiments of the invention, it will be obvious to those skilled in the art that modifications and changes may be made therein without departing from the essence of the invention. It is therefore to be understood that the exemplary embodiments are illustrative and not restrictive of the invention, the scope of which is defined in the appended claims, and that all modifications that come within the meaning and range of equivalency of the claims are intended to be included therein.
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An apparatus and method for incinerating combustible gases. The apparatus has first and second perpendicularly joined pipes and an igniter in the second pipe. Combustible gases laminarly flow into the second pipe and oxygen turbulently flows into the first. The gases turbulently mix, ignite and centrifugally swirl from the first pipe to the second pipe and then out the first pipe again. Fuel flow is regulated by flame, temperature and seismic detectors.
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CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application claims the benefit of U.S. Provisional Application No. 61/264,268 filed Nov. 25, 2010, which is incorporated by reference herein in its entirety.
FIELD OF THE INVENTION
[0002] The present invention is in the field of tags used for inventory control and security of consumer goods. More particularly, the present invention relates to an integral tagging solution that is resistant to conditions encountered during washing and dry cleaning and may withstand garment treating processes used in creating particular aesthetic effects in apparel or garment items.
BACKGROUND OF THE INVENTION
[0003] The use of radio frequency identification (RFID) to identify one of a plurality of items is well known. Typical radio frequency identification (RFID) tags or integrated circuits include a microprocessor, also known as a microchip, electrically connected to an antenna. Alternatively, the microchip is first attached to a pad having electrical leads that provides a larger attachment of “landing” area. This is typically referred to as a “strap” or “interposer.” The strap is then attached to the antenna.
[0004] The microprocessor stores data, can include identifying data unique to a specific item that is transmitted to an external receiver for reading by an operator and processing of the item. RFID tags can be attached to items for inventory control, shipment control, and the like. RFID tags are particularly useful in identifying, tracking and controlling items such as packages, pallets, and other product containers. The location of each item can be tracked and information identifying the owner of the item or specific handling requirements can be encoded into the RFID and later read by a scanning device capable of decoding and displaying the information.
[0005] Garment care and other labels are also well known and typically include care instructions, brand identification and other information such as source origin that are either required by certain regulations or are used in connection with the manufacturers marketing objectives. While RFID devices have been used in inventory management of garments and apparel items, the RFID devices can be detuned or destroyed through the washing or processing of the garment rendering tracking of the garment through subsequent inventory or treatment stations very difficult if not impossible.
[0006] What is needed therefore is a solution that protects the RFID device from such extreme conditions encountered during treatment steps and allows a retailer to continue to utilize the beneficial aspects of RFID technology.
BRIEF SUMMARY OF THE INVENTION
[0007] The embodiments of the present invention described below are not intended to be exhaustive or to limit the invention to the precise forms disclosed in the following detailed description. Rather, the embodiments are chosen and described so that others skilled in the art may appreciate and understand the principles and practices of the present invention.
[0008] The present invention relates to a garment or apparel label or tag that includes a unique RFID device arrangement, which protects the functional attributes of the RFID device during normal care and cleaning of the garment, such as with washing and dry cleaning, and also prevents damage to the RFID device during garment treating or processing to produce a particular aesthetic effect or characteristic, such as stone wash or acid washing of denim or “blue” jeans.
[0009] In one exemplary embodiment of the presently described invention, a RFID apparel tag is presented and includes a substrate that has first and second surfaces. The RFID device is adhesively secured to the substrate first face. The RFID device has a dimension and has a chip and an antenna. A liquid impermeable material is disposed over the RFID device and extends beyond the dimension of the RFID device in at least a first direction so as to substantially cover the chip and antenna and the material is permanently adhered to the substrate first face.
[0010] In a further exemplary embodiment of the presently described invention, a RFID garment label is provided and includes a substantially quadrate substrate that has first and second sides and first and second transversely extending edges and first and second longitudinally extending sides. A line of weakness extends between the first and second longitudinally extending sides and is substantially adjacent the first transversely extending end edges. A RFID inlay that has a chip and an antenna and, with the chip and antenna being laminated between plastic films. The RFID inlay has first and second sides. A layer of adhesive is provided between the second side of the RFID inlay and the first side of the substrate. The layer of adhesive suitable for the present invention may be a pressure sensitive adhesive either permanent or removable. A fluid impervious layer is disposed over the RFID inlay and is permanently secured to the first side of the substrate and along a greater extent of each of the first and second longitudinal sides and adjacent the second transversely extending end edge. The fluid impervious layer may form a flexible enclosure over the RFID inlay.
[0011] The present invention also contemplates that the fluid impervious layer may form a rigid structure over the RFID inlay.
[0012] In a further exemplary embodiment of the presently described invention, a method of producing a RFID garment tag is presented and includes the steps of providing a substrate. Then a RFID inlay is applied to a portion of the substrate. The RFID inlay is covered with a fluid impervious material such that the fluid impervious material substantially covers the RFID inlay to form a flexible bag. The fluid impervious material is welded to the substrate along each edge of the material to form a garment tag and finally, the garment tag is secured to a garment.
[0013] In addition to the foregoing embodiments, the substrate may be printed or imaged with indicia, such as care or maintenance instructions. The substrate can be provided with a line of weakness that allows for the tag once completed to be separated from the garment to which it is attached.
[0014] The fluid or liquid impervious material is a coated polyester or nylon material that can be ultrasonically welded to the substrate. The material is used to create an air gap or air layer between the RFID inlay and the material. The air gap can impact the impedance of the RFID device. In addition, a conductive gel or conductive particles themselves may be included in the air space in order to improve or enhance read range. They can also serve as a corrective measure should the RFID antenna otherwise become detached from the circuit formed by the antenna and chip.
[0015] The RFID device can be provided as an inlay construction, a chip and antenna sandwiched between plastic or PET film layers or the device can be built directly on the substrate itself. Prior to placing the RFID device on the substrate in either form it would be desirable to test the RFID device before installation on the tag structure.
[0016] Other features and advantages of the present invention will become apparent to those skilled in the art from the following detailed description. It is to be understood, however, that the detailed description of the various embodiments and specific examples, while indicating preferred and other embodiments of the present invention, are given by way of illustration and not limitation. Many changes and modifications within the scope of the present invention may be made without departing from the spirit thereof, and the invention includes all such modifications.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] These, as well as other objects and advantages of this invention, will be more completely understood and appreciated by referring to the following more detailed description of the presently preferred exemplary embodiments of the invention in conjunction with the accompanying drawings, of which:
[0018] FIG. 1 depicts an intermediate assembly showing the RFID inlay disposed on a substrate;
[0019] FIG. 2 provides a cross sectional view of the RFID inlay the substrate and covered by a material;
[0020] FIG. 3 shows a front elevation of the completed apparel tag assembly;
[0021] FIG. 4 illustrates the garment tag of the present invention secured to a garment; and
[0022] FIG. 5 is a block diagram of an exemplary method of manufacturing the apparel or garment tag of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0023] The present invention is now illustrated in greater detail by way of the following detailed description which represents the best presently known mode of carrying out the invention. However, it should be understood that this description is not to be used to limit the present invention, but rather, is provided for the purpose of illustrating the general features of the invention.
[0024] The present invention relates to an innovative garment or apparel tag or label structure that is useful in not only tracking the item through the various stages of manufacturing but is also durable enough to withstand processing and treatment steps that may be used or encountered during manufacture of the garment of post purchase care activity such as washing and dry cleaning.
[0025] As used herein the term “tag” or “label” may be used interchangeably to refer to an article identifier that may be attached to a garment or apparel item.
[0026] The term “garment” or “apparel” is used herein interchangeably to refer generally to a consumer good, which may be a shirt, blouse, pants, slacks, jacket, sweater, socks, intimate wear, shoes, accessories and the like.
[0027] Reference now is directed to FIG. 1 of the presently described invention, which generally includes a garment or apparel tag or label generally designated by reference numeral 10 . The tag 10 includes a substrate 12 that has first and second longitudinally extending sides 14 and 16 and first and second transversely extending edges 18 and 20 , respectively. The substrate 12 has a first side 22 and a second side (not shown). While the substrate 12 is shown as a single ply of material (see FIG. 2 ) it should be understood that the substrate 12 could be constructed from a ply of material that is folded over on itself one or more times depending on the desired thickness of the substrate for the end use. The substrate 12 can be selected from any suitable material such as polyester, recycled polyester material, PET, cellulosic stock, recycled paper pulp, card stock, films and foils and the like.
[0028] Continuing with reference to FIG. 1 , an RFID inlay or device 24 is disposed on the first face 22 of the substrate 12 . The RFID device 24 includes a chip 26 and antenna 28 . The antenna of the present invention may be a dipole antenna. If the substrate is a foil substrate the antenna of the RFID inlay may be constructed from the foil substrate. The chip 26 and antenna 28 may be placed directly on the substrate 12 or may be created as part of an inlay and constructed on a film layer 30 , such as PET, which is a suitable dielectric for the RFID device 24 . Exemplary RFID devices or inlays are available from Avery Dennison RFID Company, Clinton, S.C. and are sold under a number of “AD” designations depending on the particular performance criteria required for the application. For example, read range and memory requirements may represent particular performance criteria that may be needed for a particular RFID application.
[0029] The substrate 12 can be provided with printed indicia 32 for example, care instructions for use by the retailer or brand information such as the maker and location of the manufacture of the garment. Printing can be applied so as to create a first printed area where the foregoing indicia may be located and a non-printed area which may be covered by the RFID device 24 .
[0030] A line of weakness 34 may also be provided in the garment or apparel tag 10 so that the tag 10 can be removed from the garment in the event the consumer does not wish to have the device with the garment. The line of weakness preferably is adjacent the first transverse end 18 and runs perpendicular between the first and second longitudinal sides 14 and 16 . The line of weakness is another embodiment may run parallel to the first and second longitudinal sides 14 and 16 . An attachment line 36 may also be provided, which will generally be parallel to but spaced from the line of weakness to indicate to the garment manufacturer a safe distance by which to attach the tag to the garment or apparel item.
[0031] Attention is now directed to FIG. 2 a cross sectional elevation is provided of the garment tag 10 of the presently described invention. As with FIG. 1 , the garment tag 10 includes a substrate 12 in which the line of weakness 34 is shown extending through the thickness of the substrate 12 . In this embodiment, the line of weakness may be a perforation line, which includes a series of cuts and ties of sufficient strength to allow the tag to be attached to the garment but weak enough to allow a consumer to remove the tag 10 should the consumer wish to do so.
[0032] The RFID inlay 24 is shown attached to the substrate 12 by a pattern of adhesive 38 . Preferably, the adhesive is a permanent adhesive so that the RFID inlay 24 will remain bonded to the substrate. However a removable adhesive is also contemplated by the present invention. Additionally, the adhesive may be a pressure sensitive adhesive.
[0033] A fluid or liquid impervious material 40 is positioned so as to cover the RFID inlay 24 . The present invention contemplates that the impervious layer may be impervious to other components besides fluids such as dirt particles that may interact with the efficiency of the RFID inlay. The material is a coated polyester material or nylon and treated so as to be able to withstand exposure to acid or enzyme washing, dry cleaning chemicals, detergents, water and the like so as to prevent the RFID inlay 24 from becoming either partly or completely damaged, destroyed or detuned during the processing or treating by a manufacturer or consumer of a garment or apparel item. The material 40 is bonded to the substrate such as by ultrasonic welding, but other attachment means may be used such as stapling, adhesive or the like. The bonding method should however create a generally impervious seal to the RFID tag structure.
[0034] The material 40 forms a flexible bag over the RFID device 24 and creates an air space or air gap 41 over the RFID inlay or device 24 , which may further impact the tuning requirements of the RFID device 24 so the antenna must be selected to take this criteria into consideration. In addition, the space 41 could be further filled with a conductive fluid or agent such as a gel with conductive particles 43 which could be used to enhance the possible read range of the RFID device 24 and to help correct any detuning which may occur during continued processing and care of the garment. The space 41 could also be filled with an ink that will spill out if the tag having the RFID device is tampered with in a certain way.
[0035] Reference is now directed to FIG. 3 of the presently described invention in which a top or front elevation view of the RFID tag 10 is provided. The RFID device 24 is shown as being completely enclosed by the material 40 such that the dimension of the RFID device 24 is covered by the size and shape of the material 40 . The material 40 is shown as being bonded to the substrate 12 along all sides and generally inward of the substrate longitudinal sides 14 and 16 and closer to end edge 20 . That is the RFID inlay 24 and material are disposed closer to end edge 20 than the first end edge 18 , which will serve as the attachment and possible detachment point for the tag 10 from the garment.
[0036] FIG. 3 also illustrates that the top or outer surface of the material may also be provided with indicia 44 which could serve as a warning that an RFID device 24 is contained within the tag 10 or the indicia 44 could be complementary to the indicia 32 , care instructions, or provide other information relating to the garment or apparel item such as the location of the place of manufacture, brand information, removal instructions or the like. In this way, the non-printed area of the substrate is not lost and indicia can be effectively provided over the entire surface of the tag 10 .
[0037] Attention is now directed to FIG. 4 of the presently described embodiment which shows the apparel tag 10 attached to a garment 50 . The tag 10 may be attached to an area of the garment 50 such that it will be unseen when the garment is being worn, such as to the waist band 52 of a pair of pants or slacks. It should be understood however, that the tag can be attached to the outside of the garment or to another device or tag that can be separated from the garment or apparel item.
[0038] Reference is now directed to FIG. 5 of the presently described embodiment of the present invention in which a block diagram is provided that shows an exemplary method of manufacturing the apparel or garment tag or label as described herein. The process is started at step 100 by providing a substrate. The substrate can be any suitable material and can be provided in a single thickness which may be folded over onto itself depending on the needs of the end use application. Next, at step 110 the substrate can be printed with indicia relating for example to care of the garment, manufacturing or branding information or the like. As used herein, the term “printing” does not refer to solely printing by ink or toner, but rather the printing could be applied by sewing, etching, screen printing or the like. The printing can be preformed in line with the manufacturing process or the substrate may be pre-printed, prior to be supplied to the tag manufacturer.
[0039] At step 120 , a plurality of RFID inlays or RFID devices are provided and tested so that only functioning and properly performing RFID devices are used in the manufacture of the tags. The RFID devices can be tested before being incorporated into the tag manufacturing process and can be tested again before the tag is attached to a garment.
[0040] Next, at step 130 the RFID device is applied to the substrate such as by applying a pattern of adhesive so that the substrate is bonded to the RFID device so that the device will not move during further assembly of the tag. The RFID device is covered at step 140 with a fluid or liquid impervious material such that the entire dimension of the RFID device is enclosed and protected by the covering material. The covering step 140 will also create an air gap or air space between the covering material and the RFID device. The air gap can be filled with a conductive gel (gel containing conductive particles) or alternatively, conductive particles may be added or coated over the inlay area.
[0041] Next, the material is welded to the substrate at step 150 . The welding is preferably by ultrasonic energy but other means to attach the material to the substrate may be used, such as thermal energy, adhesive bonding, RF energy, mechanical fasteners and the like. Finally, at step 160 the tag is secured to the garment or apparel item to allow tracking and perhaps provider further processing or other information control.
[0042] The present invention also contemplates that a printing step 110 may be performed after the material is welded to the substrate.
[0043] In another embodiment of the present invention, the inlay is an UHF RFID device.
[0044] The apparatuses and methods disclosed in this document are described in detail by way of examples and with reference to the figures. Unless otherwise specified, like numbers in the figures indicate references to the same, similar, or corresponding elements throughout the figures. It will be appreciated that modifications to disclosed and described examples, arrangements, configurations, components, elements, apparatuses, methods, materials, etc. can be made and may be desired for a specific application. In this disclosure, any identification of specific shapes, materials, techniques, arrangements, etc. are either related to a specific example presented or are merely a general description of such a shape, material, technique, arrangement, etc. Identifications of specific details or examples are not intended to be, and should not be, construed as mandatory or limiting unless specifically designated as such. Selected examples of apparatuses and methods for physiological monitoring of a biological organism using electrical measurements are hereinafter disclosed and described in detail with reference made to FIGURES.
[0045] It will thus be seen according to the present invention a highly advantageous RFID apparel tag that can withstand garment treating and processing conditions has been provided. While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it will be apparent to those of ordinary skill in the art that the invention is not to be limited to the disclosed embodiment, and that many modifications and equivalent arrangements may be made thereof within the scope of the invention, which scope is to be accorded the broadest interpretation of the appended claims so as to encompass all equivalent structures and products.
[0046] The inventors hereby state their intent to rely on the Doctrine of Equivalents to determine and assess the reasonably fair scope of their invention as it pertains to any apparatus, system, method or article not materially departing from but outside the literal scope of the invention as set out in the following claims.
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The present invention is in the field of garment or apparel labels that includes RFID devices. More particularly, the garment or apparel tags or labels are enclosed in a flexible bag created by a fluid impervious material that protects the RFID device from maintenance and care treatments as well as garment and apparel processing conditions which may be used to provide certain aesthetic or other characteristics to the apparel item.
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FIELD OF THE INVENTION
[0001] The invention relates to a packaging wrapper for paper tissues such as handkerchiefs, comprising a wrapping forming front, rear, side and end walls surrounding the wrapper contents, with a reclosable opening cover by lid.
BACKGROUND OF THE INVENTION
[0002] Paper tissues for handkerchiefs etc. are normally folded and stacked a few, typically nine or ten, in a plastic foil wrapper. These can be carried in a pocket or a handbag, or be placed upon a desk or shelf.
[0003] These wrappers nowadays are most often equipped with a reclosable flap, enabling the user to open the wrapper, take out a handkerchief and reclose the wrapper to keep the remaining handkerchiefs protected from dirt and moisture.
[0004] The opening can be made in many different ways.
[0005] EP 0,392,224 shows a wrapper with an opening just in the edge between the front wall and the side or end wall, with an extraction opening as a cut-out under the reclosable flap. The user will have to grip the handkerchief via the cut-out in this narrow opening.
[0006] EP 0,401,621 shows a wrapper with an opening formed by a lid, separated from a side wall and a minor part of the front wall by cuts and perforations and a cut-out in a side wall. A handkerchief can be taken out fairly easy, but the user must when gripping it, separate it from the next one. To close the wrapper, the lid is put down and fastened with a reclosable flap that reaches around the side wall to be adhered to the rear wall.
[0007] EP 0,132,250 shows a wrapper where there is no need for a reclosable flap, as an opening is created in a side wall by two overlapping plastic foil pieces, the uppermost one of which has a convex shape to better cover the opening. The overlapping pieces are connected at their ends. The convex part can be lifted off the other foil piece to form an opening where the user can withdraw a handkerchief. This will form a rather narrow opening where the user will have to separate the wanted handkerchief from the next one.
[0008] EP 0,961,736 shows a wrapper where two overlapping plastic foil pieces from an opening in a side wall, where the ends are welded together to give stability to the wrapper, but the openable parts of the side wall are separated from the ends by cuts.
[0009] The opening is enabling the user to withdraw a wanted handkerchief, but still he will have to separate it from the next one.
[0010] German utility patent G 91.06.555 shows a wrapper with an opening at the end wall where the user can withdraw a handkerchief. The handkerchiefs are folded in a special way to ease the unfolding of it after it has been withdrawn from the wrapper; first Z folding and then doubling and redoubling the other direction.
[0011] Still there is a need for a wrapper where the withdrawal of a handkerchief or other paper tissue is facilitated for the user, enabling him to withdraw a handkerchief in an easy and hygienic way, without having to touch the neighboring handkerchiefs.
[0012] There is also a need for a wrapper that enables the user to withdraw and unfold a handkerchief in a single operation, preferably using only one hand.
SUMMARY OF THE INVENTION
[0013] It is an object for the present invention to make a paper tissue wrapper with a simplified handling of opening and paper tissue withdrawal.
[0014] The invention concerns a packaging wrapper, for handkerchiefs, baby care, household or other hygiene paper tissues as a pack contents, comprising a wrapper surrounding the paper tissues made of a blank, by means of which a front wall, a rear wall, a first side wall and a second side wall and two end walls are formed, with a reclosable opening in the area of the front wall, a lid mainly comprising at least part of the front wall covering the reclosable opening, with said lid having an outer side and an inner side.
[0015] This object is accomplished by the fact that the lid on its inner side is equipped with a fastening means adapted to successfully engage the upper-most lying paper tissue as one after the other of the paper tissues is taken out of the wrapper.
[0016] According to a preferred embodiment the wrapper is held closed, after it has been opened for the first time, by a closing flap that is being provided, having one end securely bonded to the outer side of the lid to be releasably fastened to the first side wall by the action of a pressure-sensitive adhesive that is applied to at least a part of the free end of the closing flap.
[0017] A preferred variant of the invention is where the lid is formed from the front wall by two perforations extending along at least part of the front wall in the vicinity of the end walls, and an overhang to the area of the first side wall.
[0018] Another preferred variant of the invention is where the reclosable opening has a length of at least half, preferably at least two thirds, and even more preferably, four fifths, of the length of the front wall in the direction starting from the overhang.
[0019] Another preferred variant of the invention is where the wrapper is stabilized by edge parts extending inwards the reclosable opening from the end walls and from the first side wall.
[0020] Preferably, the fastening means is chosen from the group of a patch of pressure-sensitive adhesive, a patch of hook material, one or more holes enabling the pressure-sensitive adhesive used to adhere the closing flap to the outer side of the lid to be exposed to the inner side of the lid.
[0021] A preferred variant of the invention is where the fastening means is placed to cooperate with the paper tissue to be pulled in an area where the paper tissue has been strengthened, preferably by embossing or gluing.
[0022] The paper tissues are preferably folded and packed in the wrapper such that when being pulled in an area presented to a user they will open up and be at least partly unfolded.
[0023] The lid can be connected to any of the side or end walls of the wrapper.
[0024] A preferred variant of the invention is where the lid is formed from the front wall by two perforations running along at least part of the front wall in the vicinity of the end walls or side walls, and an overhang to the area of the first side wall or end wall, respectively.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] [0025]FIG. 1 a perspective view of a wrapper for holding a stack of handkerchiefs in a closed position
[0026] [0026]FIG. 2 a perspective view of a wrapper for holding a stack of handkerchiefs in an open position, showing the fastening means on the inner side of the lid
[0027] [0027]FIG. 3 a view of a handkerchief in its fully opened state, indicating the fold lines used to prepare it for easy unfolding
[0028] [0028]FIG. 4 a view of a handkerchief as it is folded to lie in the wrapper
[0029] [0029]FIG. 5 a perspective view of a wrapper for holding a stack of handkerchiefs in a position as opened by a user opening the lid of the wrapper, making the top handkerchief quarter open
[0030] [0030]FIG. 6 a view of a handkerchief as it is further opened to half open by lifting in the free corner by the user
[0031] [0031]FIG. 7 an alternate way of folding a handkerchief
[0032] [0032]FIG. 8 an alternate wrapper with the lid hinged on the edge towards the end wall
DETAILED DESCRIPTION OF THE INVENTION
[0033] The packaging wrapper shown in a closed state in FIG. 1 and in an open state in FIG. 2 is made from for example a blank of thin plastic foil being cut and folded to make up a front wall 3 , a rear wall 4 , a first elongated side wall 5 and a second elongated side wall 6 and two end walls 7 , 8 . Two adjoining walls will also define an edge between them. Each end wall 7 , 8 is welded or glued together, from overlapping flaps extending from the neighboring walls.
[0034] The front wall 3 will open up as a lid 10 to make a reclosable opening 9 where paper tissues can be withdrawn from the wrapper and is equipped with a closing flap 13 to hold down the lid 10 after it has been opened for the first time.
[0035] The front wall 3 is perforated along perforation lines 16 near the edges to the end walls 7 , 8 . These perforation lines 16 will, at least partly, be torn open when the wrapper 1 is opened for the first time. The perforation lines 16 run a few millimeters from the edges, to leave edge parts 18 that help stabilize the wrapper and protect it from dirt entering and soiling the paper tissues.
[0036] Also the first elongated side wall 5 is equipped with an extension in the form of an edge part 18 to stabilize the wrapper.
[0037] The lid 10 has a slight overhang 17 that will partly cover the first elongated side wall 5 when the wrapper 1 is in a closed position. This will also stabilize the lid 10 .
[0038] Before the wrapper 1 is opened for the first time the overhang 17 is preferably fastened to the first elongated side wall 5 with a weak glue or a lacquer to make the wrapper tight against dirt.
[0039] The closing flap 13 is at one end permanently fastened to the lid 10 and at the other end the closing flap 13 can be releasably connected to the first elongated side 5 . At the outer-most part of the closing flap 13 is provided an adhesive-free grip tab.
[0040] The plastic foil used for making the wrapper 1 will normally be printed. Preferably areas of the plastic foil that are to be welded or glued to each other should be without printing, as the adhesion of the glue or the weld will be lowered on printed areas.
[0041] Instead of using plastic foil for wrapper blank material, also paper or thin aluminum foil could be used.
[0042] The lid 10 is on its inner side 12 equipped with a patch of fastening means 15 . The fastening means 15 will engage the paper tissue which is lying upper-most in the pack of folded tissues, to lift at least a part of it. The fastening means 15 should preferably be placed on the free end of the lid 10 to make the lifting action large enough to be effective. The fastening means 15 is preferably made of a patch of a pressure-sensitive adhesive, that should be tacky enough to be able to hold the tissue for lifting it, but not too tacky as it should be easy enough to dislodge the paper tissue from the fastening means 15 as the paper tissue is completely withdrawn. The adhesive Technomelt Q 8407-24 from the German company Henkel is an example of an adhesive that is suitable. The fastening means 15 could alternatively consist of a hook material, as that used for a hook-and-loop fastener. The slightly uneven surface of the paper tissue will be caught by the hooks, to let the paper tissue be lifted. It could even consist of adhesive holding the closing flap 13 on the outer side 11 of the lid 10 , acting through one or more apertures 19 in the lid 10 under the closing flap 13 .
[0043] It is advantageous, if the patch of fastening means 15 engages the paper tissue in an area of the paper tissue, which has relatively higher surface strength that other areas of the paper tissue, e.g. where it is embossed or glued. This will lessen the risk of damaging, or even tearing, the surface of the paper tissue.
[0044] Paper tissue for this type of use, as handkerchiefs, is normally made of more than one ply. Common is two, three or four plies that are glued or embossed together, mostly only at the border, to achieve a soft and skin-friendly inner area and a not quite so soft border area, that is stronger and holds the plies together.
[0045] To really take advantage of the lifting action effected by the fastening means 15 the paper tissues should be able to unfold automatically when the lid 10 is lifted. The paper tissues should preferably be folded according to the fold lines indicated in FIG. 3. First the substantially square paper tissue is Z folded at fold lines 101 and 102 , in any order, to get a ‘doubled’ paper tissue. After that, the tissue is folded at fold line 103 , and then the quadrupled paper tissue is folded according to fold lines 104 a and b , which at that moment will constitute one folding line. The resulting folded paper tissue will look like the example in FIG. 4, where the folded paper tissue is turned so that the ‘double edge’ 21 , is at the bottom and a free corner 22 at the top.
[0046] A stack of paper tissues folded to look like the paper tissue in FIG. 4 is placed in the wrapper, with the ‘double edge’ 21 at the bottom. When the lid 10 is opened for the first time, and each subsequent time, the fastening means 15 will engage the top surface of the upper-most paper tissue, preferably at the free corner 22 to lift it, and a part of the paper tissue. As the lid 10 is more opened, as in FIG. 5, a second free corner 23 will come to view.
[0047] When this second free corner 23 is pulled the folded paper tissue will partly unfold to the position shown in FIG. 6, and continued pulling at a second fee corner 23 will completely unfold the paper tissue to look like FIG. 3, and will make the fastening means 15 disengage from the paper tissue.
[0048] Thus the paper tissue easily can be unfolded to be ready to use.
[0049] Another way of stacking the folded paper tissue is according to FIG. 7 where the ‘double edge’ 21 is at the top. When this folded paper tissue is pulled by the action of the fastening means 15 it will open up partly and present a tissue corner a user can pull to extract the paper tissue. Pulling this will not result in a fully opened paper tissue as when the ‘double edge’ 21 is at the bottom, as shown in FIG. 4, but still will result in a partly opened paper tissue that easily is shaken out to fully opened.
[0050] Other ways of folding and stacking of the paper tissues can of course be used, but will not take full advantage of the possibilities of the invention.
[0051] An alternative way of arranging the wrapper 1 is briefly shown in FIG. 8. In this alternative the lid 10 is connected to the second end wall 8 so that it is opened from the first end wall 7 towards the second end wall 8 . The fasting means 15 will then lift the paper tissue a considerable distance to a very wide-open presentation. To fit this alternative the paper tissue should be folded differently from in FIG. 4, instead having its last fold as indicated in FIG. 8.
[0052] The invention is thus based on the fastening means 15 . To take full advantage of this, the lid 10 should be able to fold back more or less all the way, creating a reclosable opening 9 of the total front wall 3 length, to let the unfolding paper tissue fall flat over.
[0053] However, even without the lid 10 fully opened, it will easily be possible to get a good grip on the second free corner 23 to pull the paper tissue to fully unfold, as can be inferred from FIG. 5.
[0054] Thus, it normally be satisfactory when the reclosable opening 9 has half the length of the front wall 3 . Preferably, it will be two thirds, and even more preferably, four fifths of the length of the front wall 3 .
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A packaging wrapper, for handkerchiefs, baby care, household or other hygiene paper tissues and comprising a front wall, a rear wall, a first side wall and a second side wall and two end walls, with a reclosable opening in the area of the front wall, a lid mainly comprising at least part of the front wall covering the reclosable opening, with said lid having an outer side and an inner side, where the lid on its inner side is equipped with a fastening means adapted to successively engage the upper-most lying paper tissue as one after the other of the paper tissues is taken out of the wrapper.
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BACKGROUND
[0001] 1. Field
[0002] The present disclosure relates to acquiring and releasing a shared resource via a lock semaphore and, more particularly, to acquiring and releasing a shared resource via a lock semaphore utilizing a state machine.
[0003] 2. Background Information
[0004] Typically, processing or computer systems allow multiple programs to execute substantially simultaneously. Multiple programs may execute substantially simultaneously utilizing techniques such as, for example, time slicing, parallel execution or multiple processing engines. Furthermore, it is possible for multiple parts of a program, or threads, to execute substantially simultaneously in much the same manner. Techniques that allow for this substantially simultaneous execution are often referred to as being multi-tasking, multi-threading or hyper-threading. An example of a multi-tasking technique may allow for a music player and a word processor to be run substantially simultaneously, so a user could listen to music while they write a document. An example of a multi-threading technique may be a word processor that allowed editing of a document while simultaneously printing the same document.
[0005] These threads, processes, or programs, hereafter, collectively referred to as “threads,” often access shared resources. These shared resources may include physical hardware or other sections of executable instructions, such as, for example, a common library. These shared resources may not be capable of being substantially simultaneously utilized by multiple threads. For example, it is not common for a printer to print two or more documents simultaneously; however, in a multi-threaded environment two or more threads may attempt to simultaneously print to the printer. Of course, this is merely one example of a shared resource that may be incapable of being substantially simultaneously utilized by multiple threads.
[0006] To prevent errors or other undesirable effects that may occur when multiple threads attempt to simultaneously use a shared resource a variety of techniques are known. In one technique, thread access to a shared resource may be governed by a semaphore lock, hereafter, “lock.” In this context, a lock is a signal or a flag variable used to govern access to shared system resources. A lock often indicates to other potential users or threads that a file or other resource is in use and prevents access by more than one user or thread.
[0007] In the printer example above, a first thread may acquire a lock on the printer, print the document, and release the lock on the printer. The second thread may attempt to acquire the printer's lock. Upon finding the printer is already locked by the first thread, the second thread often waits to acquire the lock. When the first thread releases the printer lock, the second thread may then acquire the printer lock, print the second document, and release the lock on the printer. In this example, contention for access to the printer is governed.
[0008] Often it is possible for a single thread to hold multiple locks at a given time. Using traditional techniques, when a thread holds multiple locks at the same time, the associated dynamic memory allocation and deallocation is often proportional to the sum of the number of locks, the number of threads, and the number of lock acquisitions. In modem systems, this resulting number is often quite large. In addition, frequent memory allocations and dealloctions may consume a large amount of processing time and other system resources. A need, therefore, exists for an improved system or technique for implementing the acquiring and releasing of a shared resource via a lock semaphore.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] Subject matter is particularly pointed out and distinctly claimed in the concluding portions of the specification. The disclosed subject matter, however, both as to organization and the method of operation, together with objects, features and advantages thereof, may be best understood by a reference to the following detailed description when read with the accompanying drawings in which:
[0010] FIG. 1 is a flowchart illustrating an embodiment of a technique for acquiring and/or releasing a lock in accordance with the disclosed subject matter;
[0011] FIG. 2 is a flowchart illustrating an embodiment of a technique for acquiring and/or releasing a lock in accordance with the disclosed subject matter;
[0012] FIG. 3 is a state diagram illustrating an embodiment of a state machine utilized by a technique for acquiring and/or releasing a lock in accordance with the disclosed subject matter;
[0013] FIG. 4 is a table detailing the possible states of a state machine utilized within an embodiment of a technique for acquiring and/or releasing a lock in accordance with the disclosed subject matter; and
[0014] FIG. 5 is a block diagram illustrating an embodiment of an apparatus and a system that allows for acquisition and release of a lock in accordance with the disclosed subject matter.
DETAILED DESCRIPTION
[0015] In the following detailed description, numerous details are set forth in order to provide a thorough understanding of the present disclosed subject matter. However, it will be understood by those skilled in the art that the disclosed subject matter may be practiced without these specific details. In other instances, well-known methods, procedures, components, and circuits have not been described in detail so as not to obscure the disclosed subject matter.
[0016] FIG. 1 is a flowchart illustrating an embodiment of a technique for acquiring and/or releasing a lock in accordance with the disclosed subject matter. Block 110 illustrates that a requesting thread, or agent associated with the thread, may select an action to perform upon the lock. In one embodiment, the action may be selected from a group of actions including: acquiring the lock, trying to acquire the lock, or releasing the lock.
[0017] Block 120 illustrates that the current state of the lock may be asynchronously queried. In one embodiment, the lock may utilize a state machine with four valid states, such as, for example the state machine shown in FIG. 3 .
[0018] FIG. 3 is a state diagram illustrating an embodiment of a state machine utilized by a technique for acquiring and/or releasing a lock in accordance with the disclosed subject matter. One embodiment of the state machine may include four valid states. The embodiment may also involve a lock that includes a flag value, a pointer to a first thread in a queue of threads waiting to acquire the lock, and a pointer to a last thread in the queue to acquire the lock. In one embodiment, the flag value may indicate both whether or not the lock is being held and if there is a queue of threads waiting to acquire the lock. In other embodiments, the flag value may only indicate whether or not the lock is being held, and another value may indicate if a queue exists. It is also contemplated that the existence of the queue may be determined by the first and last thread pointers. It is further contemplated that the “pointer” to the threads may be an address value, a unique thread identifier or some other value that would facilitate access to the threads. In the embodiments illustrated by FIGS. 3 and 4 , the state of the lock may be determined by the flag value and thread pointers; however, other techniques for determining the lock state are contemplated.
[0019] State 310 may indicate that no thread holds the lock and there are no threads waiting in a queue to acquire the lock. In the illustrated embodiment, the flag value, the first thread pointer, and the last thread pointer may all be set to zero. However, it is contemplated that other values may be used in other embodiments to represent this un-acquired state. In this embodiment, state 310 may be the initial state of the lock. Also in this embodiment, the lock, since it is not held, may not be released. In one embodiment, an attempt to release the lock may result in an error. Furthermore, in this embodiment, the lock may only be acquired (via either an acquire or try action). The act of acquiring the lock may move the lock to state 320 . However, other embodiments are contemplated.
[0020] State 320 may indicate that a thread holds the lock and no threads are waiting in the queue. In the illustrated embodiment, the flag value may be set to one, and the first and last thread pointers may be set to zero. However, it is contemplated that other values may be used in other embodiments to represent this acquired state. In this embodiment, if the lock is released, the lock may return to state 310 . Also, in this embodiment, if the lock is acquired, the lock may move to state 330 . However, other embodiments are contemplated.
[0021] State 330 may indicate that a thread holds the lock and one thread is waiting in the queue. In the illustrated embodiment, the flag value may be set to two, and the first and last thread pointers may point to the same thread. This thread is represented in FIGS. 3 & 4 as “H” which stands for the thread at the head of the queue. However, it is contemplated that other values may be used in other embodiments to represent this state. In this embodiment, if the lock is released, the lock may return to state 320 . Also, in this embodiment, if the lock is acquired, the lock may move to state 340 . However, other embodiments are contemplated.
[0022] State 340 may indicate that a thread holds the lock and that more than one thread is waiting in the queue. In the illustrated embodiment, the flag value may be set to two, and the first and last thread pointers may point to the different threads. The last thread is represented in FIGS. 3 & 4 as “T” which stands for the thread at the tail of the queue. However, it is contemplated that other values may be used in other embodiments to represent this state. In this embodiment, if the lock is released, the lock may return to either state 330 or remain at state 340 , depending upon whether releasing the lock changes the queue length to one. Also, in this embodiment, if the lock is acquired, the lock may remain at state 340 . It is contemplated that when the lock remains at state 340 after a release or acquire action, that either the first or last thread pointer may be changed to represent the performed action. However, other embodiments are contemplated.
[0023] FIG. 4 is a table detailing the possible states of a state machine utilized within an embodiment of a technique for acquiring and/or releasing a lock in accordance with the disclosed subject matter. It provides a summary of the state machine illustrated in FIG. 3 . Row 410 summarizes state 310 . Row 420 summarizes state 320 . Row 430 summarizes state 330 . Row 440 summarizes state 340 . However, FIGS. 3 & 4 merely illustrate one embodiment of the disclosed subject matter and other embodiments are contemplated.
[0024] Returning to FIG. 1 , block 130 illustrates that once the current state of the lock has been determined, in block 120 , the lock's next state may be speculatively determined. In one illustrative example, the thread may request that the lock be acquired. The current state of the lock may show that the lock is not presently held. Therefore, utilizing the embodiment of the state machine illustrated by FIG. 3 , the next state of the lock, after the requested “acquire” action is performed, may be speculatively determined to be a state that represents the lock being held, but having no threads in a queue waiting to acquire the lock.
[0025] Block 140 illustrates that an attempt to transition the lock to the next state may be made. It is contemplated that this, and possibly any, alteration of the lock's state may be done via a technique that attempts to minimize the occurrence of race conditions and other undesirable thread related effects. A race condition is often defined as an undesirable situation that occurs when a device or system attempts to perform two or more operations at substantially the same time, but because of the nature of the device or system, the operations must be done in the proper sequence in order to be done correctly. In one embodiment, the alteration may be performed by a “compare-and-store” operation (a.k.a. a “test-and-set” operation) that confirms that a variable is equal to an expected value before allowing the variable to be set to a new value. However, these are merely a few non-limiting examples to which the disclosed subject matter is not limited by.
[0026] Block 150 illustrates that the state transition may not be, in some embodiments, successful. It is contemplated that, in one embodiment, the state of the lock may change between block 120 and block 140 . It is also contemplated that the thread or performer of the technique may not be aware of this change in state before the transition is attempted. In one illustrative example, a second thread may alter the state of the lock between blocks 120 and 140 . This may cause the attempted state transition to fail. It is contemplated that transition may fail if such a change, for example, has occurred. However, other possible failures are contemplated.
[0027] Block 160 illustrates that, if the state transition of block 140 failed, the selected action may be examined. The selected or requested action of block 110 may be, in one embodiment: try to acquire the lock, acquire the lock, or release the lock. However, other actions are within the scope of the disclosed subject matter.
[0028] Block 170 illustrates that, in one embodiment, if the selected action was to merely try to acquire the lock and the state transition failed, the technique may indicate to the requesting thread that the lock was not acquired. Conversely, in one embodiment, if the selected action was “acquire” or “release,” FIG. 1 illustrates that the technique may repeat blocks 120 , 130 , and 140 , until the lock has successfully transitioned state.
[0029] FIG. 2 is a flowchart illustrating an embodiment of a technique for acquiring and/or releasing a lock in accordance with the disclosed subject matter. FIG. 2 is an extension of FIG. 1 that details an embodiment of a technique that may be employed if the state transition of block 140 of FIG. 1 is successful.
[0030] Block 210 of FIG. 2 illustrates that different events may transpire depending upon the action selected (see block 110 of FIG. 1 ). If the selected action was “acquire” or “try,” block 220 illustrates that different actions may be performed based upon whether or not the lock was acquired. In one illustrative embodiment, acquiring the lock may be synonymous with transitioning the lock into state 310 of FIG. 3 . However, this is merely one illustrative embodiment, and other embodiments are contemplated.
[0031] Block 230 illustrates, if the lock was acquired, that an indication that the lock was acquired may be made to the thread. In one embodiment, this indication may include deselecting (or setting to the “false” state) a spin flag in the thread. This spin flag may have prevented execution of the thread while it waited on the acquisition of the lock. However, it is contemplated that other forms of indication are possible and that this is merely one illustrative example. It is also contemplated that the indication may only be made in certain embodiments of the disclosed subject matter.
[0032] Block 250 illustrates that, if the lock was not acquired and the selected action was “acquire,” the thread requesting the lock may be added to a queue of threads waiting to acquire the lock. In one embodiment, the thread may simply be added to the end or tail of the queue. However, it is contemplated that other schemes may be used to prioritize access to the lock.
[0033] In one illustrative embodiment, the added thread may be the first and only thread in the queue. For example, the lock may be transitioned from state 320 of FIG. 3 to state 330 . In this case, adding the thread to the queue may include setting the flag value of the lock to two, and placing a pointer (or some other value to facilitate access) to the thread in the first and last thread pointer values of the lock. However, this is merely one highly specific embodiment of the disclosed subject matter and other embodiments are contemplated.
[0034] In a second illustrative embodiment, the added thread may be the second thread in the queue. For example, the lock may be transitioned from state 330 to state 340 . In this case, adding the thread to the queue may include not changing the flag value or the first thread pointer of the lock, and placing a pointer (or some other value to facilitate access) to the thread in the last thread pointer value of the lock. However, this is merely one highly specific embodiment of the disclosed subject matter and other embodiments are contemplated.
[0035] In a third illustrative embodiment, the added thread may be the third or higher thread in the queue. For example, the lock may be transitioned from a previous state 340 to new state 340 . In this case, adding the thread to the queue may include not changing the flag value or the first thread pointer of the lock, but placing a pointer (or some other value to facilitate access) to the thread in the last thread pointer value of the lock. This new last (or “tail”) thread pointer would replace the previous last thread pointer. However, this is merely one highly specific embodiment of the disclosed subject matter and other embodiments are contemplated.
[0036] Block 255 of FIG. 2 illustrates that the now queued thread may wait to receive notification that the lock is acquired. It is contemplated that in one embodiment, the thread may await notification that the lock is available to be acquired. In one embodiment, the thread may be prevented from executing while waiting. In another embodiment the thread may continue to execute a portion of the thread that does not need or desire access to the resource controlled by the lock.
[0037] Block 260 illustrates that, if the selected action was to release the lock, the number of threads in or, in another embodiment, the existence of a queue of threads waiting to acquire the lock may be determined. In one embodiment, the approximate size of the queue may be determined by a flag value associated with the lock. In another embodiment, the existence or depth of the queue may be determined by comparing the first and last queued thread pointers. However, these are merely two illustrative examples and it is contemplated that other schemes for determining the existence or depth of a queue may be used.
[0038] Block 270 illustrates that if no queue exists, the lock may be released. In one embodiment, illustrated by FIG. 3 , this may involve transitioning the lock from state 320 to state 310 . In this embodiment, block 270 of FIG. 2 may be synonymous with block 140 of FIG. 1 . However, it is contemplated that other embodiments may include a more involved releasing mechanism, such as for example, a pre-defined return value or centralized status mechanism. These are merely a few non-limiting embodiments.
[0039] Block 280 of FIG. 2 illustrates that if a queue does exist, the first thread in the queue may be identified or accessed. In one embodiment, this may involve utilizing the pointer value associated with the first thread pointer value of the lock. However, this is merely one illustrative embodiments and other embodiments are contemplated.
[0040] Block 283 illustrates that the first thread may be removed from the queue. In one embodiment this may include editing both the state of the lock and the de-queued thread. However, other schemes for de-queuing the thread are contemplated. Three highly specific embodiments are described below; however, these are merely a few non-limiting examples.
[0041] In one illustrative embodiment, the de-queued thread may be the first and only thread in the queue. For example, the lock may be transitioned from state 330 of FIG. 3 to state 320 . In this case, removing the thread from the queue may include setting the flag value of the lock to one, and setting the first and last thread pointer values to zero. However, this is merely one highly specific embodiment of the disclosed subject matter and other embodiments are contemplated.
[0042] In a second illustrative embodiment, the queue may only include two threads. For example, the lock may be transitioned from state 340 to state 330 . In this case, removing the thread from the queue may include not changing the flag value or the last thread pointer of the lock, while placing a pointer (or some other value to facilitate access) to the second queued thread in the first thread pointer value of the lock. In one embodiment, the first thread may include a “next thread” value that includes a pointer to the next thread in the queue. This next thread value may be accessed to determine the proper value to set the new first thread pointer in the lock. However, this is merely one highly specific embodiment of the disclosed subject matter and other embodiments are contemplated.
[0043] In a third illustrative embodiment, the queue may include more than two threads. For example, the lock may be transitioned from a previous state 340 to a new state 340 . In this embodiment the actions may be identical to the second illustrative embodiment. Unlike the second embodiment, where the first and last thread pointers ultimately contained the same value in state 330 , this embodiment would result in the first and last thread pointers containing different values in state 340 . However, this is merely one highly specific embodiment of the disclosed subject matter and other embodiments are contemplated.
[0044] Block 286 of FIG. 2 illustrates that the de-queued thread may be notified that it has acquired the lock. In one embodiment, this indication may include deselecting (or setting to the “false” state) a spin flag in the thread. This spin flag may have prevented execution of the thread while it waited on the acquisition of the lock. However, it is contemplated that other forms of indication are possible and that this is merely one illustrative example. It is also contemplated that the indication may only be made in certain embodiments of the disclosed subject matter.
[0045] It is also contemplated that in one embodiment, some, if not all, of the actions illustrated in FIG. 2 may be included as part of blocks 140 & 150 of FIG. 1 . In this embodiment, blocks 140 & 150 may be implemented as an atomic action, such as, for example, a “compare-and-store” operation (a.k.a. a “test-and-set” operation) that confirms that a variable is equal to an expected value before changing the variable to be set to a new value.
[0046] FIG. 5 is a block diagram illustrating an embodiment of an apparatus 501 and a system 500 that allows for acquisition and release of a lock 510 in accordance with the disclosed subject matter. In one embodiment, the lock 510 may include a state value 520 . The state value may include a flag value 523 to indicate whether or not the lock is currently held and/or the approximate length of a queue of threads 550 waiting to acquire the lock, a first thread value 525 to facilitate access to a first thread 560 , and/or a last thread value 528 to facilitate access to a last thread 580 .
[0047] In one embodiment, the system 500 may include a queue of threads 550 that are waiting to acquire the lock 510 . While FIG. 5 illustrates a queue having at least four threads and queue having zero or more threads is within the scope of the disclosed subject matter. The queue may include a first thread 560 , a last thread 580 , a second thread 570 , and a plurality of other threads 590 . In one embodiment, for example if the queue includes only one thread, the first and last thread may be identical. In one embodiment, each thread in the queue may include a wait value 593 that indicates that the thread is waiting to acquire the lock, and/or a next thread value 597 that facilitates access to the next thread in the queue. However, it is contemplated that other state and memory structures may be utilized by the threads.
[0048] In one embodiment, the apparatus 501 and system 500 may include a lock acquirer 530 to facilitate acquiring the lock 510 . In one embodiment, the lock acquirer may be capable of performing all or part of the technique illustrated by FIGS. 1 & 2 and described above. In another example, the lock acquirer may be capable of determining if the lock is held. If so, the lock acquirer may place a requesting thread within the queue 550 . It is contemplated that the requesting thread may be placed at the end of the queue, or in the front or middle of the queue if a prioritized queue scheme is used. However, these are merely a few non-limiting examples of embodiments within the scope of the disclosed subject matter.
[0049] In one embodiment, the apparatus 501 and system 500 may include a lock releaser 540 to facilitate releasing the lock 510 . In one embodiment, the lock releaser may be capable of performing all or part of the technique illustrated by FIGS. 1 & 2 and described above. In another example, the lock releaser may be capable of determining if a queue 550 exists or is empty. If the queue exists, the lock acquirer may remove the first thread 560 from the queue and move the second thread 570 to the first position in the queue. The lock releaser may then notify the first thread 560 that the lock is available. It is contemplated that, in one embodiment, the lock releaser may use the next thread value 597 to access the second thread and the wait value 593 to notify the first thread that the lock is available. However, these are merely a few non-limiting examples of embodiments within the scope of the disclosed subject matter.
[0050] In one embodiment, the apparatus 501 and system 500 may be capable of limiting the dynamic memory allocation and deallocations to a number substantially related or proportional to the sum of the number of locks, and the number of threads. It is further contemplated that alterations of the lock's state 520 or the thread's values 593 & 597 may be done via a technique that attempts to minimize the occurrence of race conditions and other undesirable thread related effects. In one embodiment, the alteration may be performed by a “compare-and-store” operation (a.k.a. a “test-and-set” operation) that confirms that a variable is equal to an expected value before allowing the variable to be set to a new value. It is also contemplated that a thread's wait value 593 and next thread value 597 may be stored within a memory and within separate cache lines of that memory. In another embodiment, the lock's queue length value 523 and last thread value 528 may be stored within the same cache line of a memory. The lock's first thread value 525 and a duplicate or shadowed version of the last thread value may be stored within a second memory cache line. However, these are merely a few specific embodiments of the disclosed subject matter and other embodiments are possible and contemplated.
[0051] The techniques described herein are not limited to any particular hardware or software configuration; they may find applicability in any computing or processing environment. The techniques may be implemented in hardware, software, firmware or a combination thereof. The techniques may be implemented in programs executing on programmable machines such as mobile or stationary computers, personal digital assistants, and similar devices that each include a processor, a storage medium readable or accessible by the processor (including volatile and non-volatile memory and/or storage elements), at least one input device, and one or more output devices. Program code is applied to the data entered using the input device to perform the functions described and to generate output information. The output information may be applied to one or more output devices.
[0052] Each program may be implemented in a high level procedural or object oriented programming language to communicate with a processing system. However, programs may be implemented in assembly or machine language, if desired. In any case, the language may be compiled or interpreted.
[0053] Each such program may be stored on a storage medium or device, e.g. compact read only memory (CD-ROM), digital versatile disk (DVD), hard disk, firmware, non-volatile memory, magnetic disk or similar medium or device, that is readable by a general or special purpose programmable machine for configuring and operating the machine when the storage medium or device is read by the computer to perform the procedures described herein. The system may also be considered to be implemented as a machine-readable or accessible storage medium, configured with a program, where the storage medium so configured causes a machine to operate in a specific manner. Other embodiments are within the scope of the following claims.
[0054] While certain features of the disclosed subject matter have been illustrated and described herein, many modifications, substitutions, changes, and equivalents will now occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes that fall within the true spirit of the disclosed subject matter.
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The present disclosure relates to acquiring and releasing a shared resource via a lock semaphore and, more particularly, to acquiring and releasing a shared resource via a lock semaphore utilizing a state machine.
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STATEMENT OF GOVERNMENT INTEREST
The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention generally relates to electrical grounding equipment, and more particularly, to a shield ground adapter ("SGA" hereinafter) and to a conduit ground adapter ("CGA" hereinafter) designed to shunt high level electromagnetic ("EM" hereafter) energy from cable shields or conduits to a metallic boundary or ground plane such as a kickpipe/stuffing tube ("KP/ST" hereinafter) assembly, through which the cable passes. The EM energy can be caused by lightning, or by such high level EM sources as an electromagnetic pulse ("EMP" hereinafter). This shunting of EM energy from the cable shield or conduit to the metallic boundary, through which the cable passes, prevents the high level currents, voltages and EM fields induced thereby, from penetrating into the space protected by the metallic boundary or ground plane, through which the cable passes.
(2) Description of the Prior Art
Prior to the present invention all ground adapters, SGA's and CGA's utilized either soldered, compression or spring type devices to electrically connect the shield or conduit to a mechanical adapter assembly. Such assemblies were then threaded into KP/ST assemblies to provide mechanical connection to the ground plane or metallic boundary. The electrical connection to the ground plane or metallic boundary was provided by either mechanical threads, or by a spring type device, which typically required that the cable, conduit or KP/ST assembly meet stringent dimensional tolerances. Electrical connection to the KP/ST assemblies were typically made using the inside threads of the KP/ST. These thread interfaces have been shown to degrade over time and environmental conditions until the EMI/EMP ground is completely lost. With all of these heretofore known devices, the size of the ground adapter that was used was dependent on both the cable or conduit size and on the KP/ST size, which required a stock of separate ground adapters for every different cable/conduit and ST/KP assembly size combination. If, for example, ten different sizes of cable or conduit and five different sizes of KP/ST assemblies were required, an inventory of as many as fifty differently sized ground adapters had to have been stocked. Furthermore, cable conduits and KP/ST assemblies that were to be nominally of the same size but were manufactured by different companies have nonetheless had different dimensions. In order to accommodate such dimensional differences, a stock of a set of ground adapters for each manufacturer had to have been maintained. These heretofore known ground adapter devices suffered from the further limitation that no ground adapter was completely cross-compatible, as, for example, an adapter designed for grounding shields was not compatible for use with a conduit, and vice versa.
SUMMARY OF THE INVENTION
In accordance with one object of the present invention, a universal ground adapter (UGA) is provided that is universally compatible with all varieties of cable, conduit and KP/ST assemblies. The UGA is not dependent on the inner threads of the KP/ST assembly to achieve its low impedance, high frequency, high current capable ground.
In accordance with a further object of the present invention, such a ground adapter is provided that enables a wideband, 360 degree, low-impedence connection to exist between any selected member to be shielded and a mechanical shielding device.
In accord therewith, a cable shield-to-conduit connection, a cable shield-to-KP/ST assembly connection, a conduit-to-conduit connection, and a conduit-to-KP/ST assembly connection are provided.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects, features and advantages of the present invention will become apparent upon reference to the following description of the preferred embodiments, and to the drawings, wherein:
FIG. 1 is partially sectional, partially pictorial view of a female ground adapter of a universal ground adapter in accordance with the present invention;
FIG. 2 is a partially sectional, partially pictorial view of a male ground adapter of a universal ground adapter in accordance with the present invention;
FIG. 3 is a partially sectional, partially pictorial view of the female ground adapter of the universal ground adapter configured for a comparatively smaller cable, conduit or KP/ST assembly in accordance with the present invention;
FIG. 4 is a partially sectional, partially pictorial view of the male ground adapter of the universal ground adapter configured for a comparatively larger cable, conduit or KP/ST assembly in accordance with the present invention;
FIG. 5 is a partially sectional, partially pictorial view of the universal ground adapter of the present invention in an exemplary embodiment connecting conduit to a KP/ST assembly; and
FIG. 6 and FIG. 7 are partially sectional, partially pictorial views of alternative embodiments of the ground adapter of the present invention, respectively connecting to shield and conduit.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to FIG. 1, there is shown a female ground adapter of the universal ground adapter in accordance with the present invention. Electrical contact with the cable 10 is typically made with a stainless steel or bronze iris or other conductive annular spring 12, contacting the cable shield 14 via a slot cut in the cable jacket 16. An environmental seal is maintained by annular, preferably rubber, O-ring seals 18 and 20. The constricting pressure of the iris spring 12 on the cable shield 14 is maintained via downward pressure from the pressure ring 22 on the iris spring 12 which is forced inward via the slope of the top of the adapter nut 24. Downward pressure on the pressure ring 22 is applied via the O-ring seal 18 which is, in turn, compressed via the aluminum, stainless steel, bronze or other conductive or non-conductive outer nut 26. The iris spring 12 preferably is a 360°, helically wound element that, as compressed, substantially contacts itself with substantially no gaps between turns in order to accomodate the EMP frequencies and wavelengths typically encountered. The outer nut 26 is threaded onto the aluminum, stainless steel, or bronze or other conductive adapter nut 24. Electrical contact to ground or to a metallic barrier is provided by threading the female pipe-threaded adapter nut 24 onto a male pipe-threaded metallic pipe 28. Conduit of course may be substituted for the cable as appears more fully herein.
The device of FIG. 2 is the same as that of FIG. 1, and similar components in FIG. 2 carry the same notation and operate similarly to those shown and described with reference to FIG. 1. The adapter nut 30 differs from the adapter nut 24 of FIG. 1 in that it has a male pipe-thread as opposed to the female. The thread size is however the same for adapter nut 30 of FIG. 2 as that of the adapter nut 24 of FIG. 1.
The device of FIG. 3 is the same as those of FIG. 1 and FIG. 2, and the parts 32, 34, 36, 38, and 40 of FIG. 3 are similar in operation to the parts 12, 18, 20, 22 and 26 respectively of FIG. 1. The diameter of the cable which they are adapted to is different, and, particularly, FIG. 3 shows an adapter to fit a cable or conduit which is of a smaller diameter than the diameter for which the devices of FIG. 1 and FIG. 2 fit. Adapter nut 42 of FIG. 3 and adapter nut 24 of FIG. 1 have the same size of pipe-thread. The difference between adapter nut 42 of FIG. 3 and the adapter nut 24 of FIG. 1 is that the adapter nut 42 is sized, on the top thereof, to fit the different diameter of the parts 32, 34, 36, 38, and 40.
Similarly, the device of FIG. 4 is the same as the devices of FIG. 3 as well as of FIG. 1 and of FIG. 2, and the parts 44, 46, 48, 50, and 52 thereof are similar in operation to the parts 32, 34, 36, 38, and 40, respectively, of FIG. 3. FIG. 4 shows the parts 44, 46, 48, 50, and 52 adapted to fit a larger diameter cable or conduit. Again, the adapter nut 54 has the same male thread sizes as the part 30 of FIG. 2, the difference therebetween being the larger diameter of the top thereof to fit the parts 44, 46, 48, 50, and 52. The device of FIG. 4 may be adapted to smaller diameter cables or conduit in a similar manner as the device of FIG. 3, and conversely, the device of FIG. 3 may be adapted to accommodate larger diameter cable or conduit in manner similar to that of the device of FIG. 4.
Referring now to FIG. 5, the operation of the device of FIG. 5 is the same as those of FIG. 1 and FIG. 2, and similar components in FIG. 5 carry the same notation and operate in the same manner as those shown and described with reference to FIG. 1 or FIG. 2. The difference is that the female adapter nut 24 is threaded into the male adapter nut 30. Adapter member illustrated generally by arrow 70 of FIG. 5 is shown connecting to an aluminum, steel or other conductive KP/ST assembly 56. The iris spring 12 now provides electrical contact to the outside wall of the KP/ST assembly 56 and the O-ring 1 provides the environmental seal with the KP/ST assembly 56. The KP/ST assembly 56 is connected to the metallic boundary 58 via the weld 60. Adapter member illustrated generally by arrow 72 of FIG. 5 is shown connecting at the other end to a conduit 62 where the iris spring 12 provides electrical contact to the braid 64 of the conduit 62. The O-ring 18 supplies the environmental seal with the conduit jacket 66. Continuous electrical contact from the conduit 62 to the metallic boundary 58 is thus provided via the conduit braid 64 to the top iris spring 12 to the adapter nut 24 to the adapter nut 30 to the bottom iris spring 12 to the KP/ST assembly 56 and the weld 60. Full, wideband, 360 degree low-impedence connection between the braid 64 and metallic boundary 58 is thereby provided in the exemplary FIG. 5 embodiment. Other exemplary connections are possible without departing from the inventive concept.
For one example, FIG. 6 shows the device of FIG. 3 connecting to cable. Substituting the adapter member of FIG. 6 for the adapter member 72 of FIG. 5 provides continuous electrical contact from the cable shield to the metallic boundary in the same manner as that described above for the conduit member of FIG. 5.
For another example, FIG. 7 shows the same device as adapter member 72 of FIG. 5. Substituting the adapter member of FIG. 7 for the adapter member 70 of FIG. 5 provides continuous electrical contact from the conduit 62 of section member 72 (FIG. 5) to the conduit 62 of FIG. 7.
Any size of cable or conduit may in this manner be connected to any other size KP/ST assembly, cable or conduit. The pipe thread interface between adapter nuts 24 and 30 (FIG. 5) provides both the necessary environmental seal and 360 degree mechanical connection as well as avoids electrical contact problems associated with standard straight threads.
The above described universal ground adapter thereby provides an EM interference and EMP grounding of any one of conduit, cable and KP/ST assembly independently of size of any two joined members and in such a way as to maintain environmental integrity and electrical connection.
Many modifications of the presently disclosed invention will become apparent to those skilled in the art without departing from the scope of the instant invention.
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An electromagnetically shielded connector assembly that enables connectionrom any one of conduit and cable to any one of conduit, cable and ground plane irrespective of the particular sizes of the members to be connected.
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BACKGROUND OF THE INVENTION
Hydraulic sewer cleaning equipment of the type which utilizes a hydraulic reverse acting jet to feed a hose down the sewer has been commercially produced for approximately ten years. The hydraulic jet which issues from the nozzle cuts debris out of the sewer, and flushes it down the sewer away from the debris that is being cleaned. The equipment has generally utilized a hose reel for feeding out the hose under a pressure of more than a thousand pounds per square inch, and a down the manhole sewer guide which has required workmen to feed the hydraulic hose down the manhole in a direction parallel to the sewer being cleaned. Such equipment has not worked well when the hose has been fed laterally to the manhole. The reasons why this is true has not been readily assertainable, since the section of hose which enters the sewer is normally submerged in murky water which prevents visual observation. In addition, the prior art equipment has required a crew of men to operate. It has been necessary in instances where the manhole has been remotely located, to have one man uncoil the hose; another to pull the hose laterally and maintain it in a horizontal bowed condition; while a third man has been stationed at the manhole to feed the hose down the manhole in a direction parallel to the sewer being cleaned. The man stationed at the manhole has had to pull the hose with continuous physical effort while the hose is fed down the sewer; and it has been extremely difficult for the man located at the manhole to retrieve the hose while it is under pressure to produce a reverse cleaning action of the sewer.
Accordingly, it is an object of the present invention to provide a hydraulic sewer cleaning system which will service manholes that are remotely located from the hose reel with a minimum of manual effort and which can utilize the hose reel to slowly and precisely retrieve the hose under pressure to provide improved cleaning action.
Another object of the present invention is the provision of a new and improved down the manhole hose guide which overcomes binding of the hydraulic hose even when it is fed laterally into the manhole.
Another object of the present invention is the provision of a new and improved apparatus which, after the hose is strung down the manhole, can be put under the hose, then set on the top ring of the manhole in such manner that the hydraulic pressure in the hose will thereafter lock in its place.
Another object of the present invention is the provision of a new and improved means for retrieving the hose laterally from the manhole and for guiding it onto the hose reel.
Further objects and advantages of the invention will become apparent to those skilled in the art to which the invention relates from the following description of the preferred embodiments described with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic elevational view of the improved system of the present invention.
FIG. 2 is an enlarged fragmentary side view of an improved down the sewer hose guide capable of feeding the hose from the manhole into the sewer without binding regardless of the direction from which the hose is fed into the manhole.
FIG. 3 is an enlarged plan view of a manhole hose guide of the present invention with the guide being shown in position on a manhole ring that is indicated by dot-dash lines.
FIG. 4 is a side elevational view of the manhole and manhole hose guide shown in FIG. 3.
FIG. 5 is a side elevational view taken approximately on the line 5--5 of FIG. 1.
FIG. 6 is a plan view taken approximately on the line 6--6 of FIG. 5.
FIG. 7 is a side elevational view of FIG. 6.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Although the improved hydraulic system of the invention may be otherwise embodied, it is herein shown and described as carried by a truck on which there is also mounted a water tank and hydraulic pump, not shown, to be used therewith. A hose reel 12 is mounted across the back of the truck on a transverse horizontal axis, so that the hose can be uncoiled in a direction parallel to the longitudinal axis of the truck. Suitable equipment, not shown, is provided for connecting the hose on the reel to the hydraulic pump, and for rotating the hose reel in either direction, by means of a power take off from the motor of the truck. The truck also contains a type of traverse mechanism 14 that is mounted on one end of an arm 16, the other end of which is suitably pivoted about a vertical axis to the back of the truck as at 18. The pivot 18 is located at approximately the longitudinal mid point of the hose reel, and is positioned slightly rearwardly of the hose reel, so that the hose will uncoil from the reel 12 in a sweeping arc while under pressure, and while being fed through the traverse mechanism 14. The prior art traverse mechanisms have employed rotatable cylindrically shaped pins for loosely confining the hose, and which allow movement from side to side in the traverse bracket. With this prior art mechanism, it has been possible, particularly when the hose is being fed out under pressure, for the hose to buckle between the hose reel and the traverse mechanism. In addition, it has been extremely difficult to move the traverse mechanism laterally with the hose under pressure.
In addition, the prior art has had a down the manhole sewer entrance guide having a frame which carries a series of rollers arranged to guide the hose along the bottom thereof in a 90 degree entrance bend for the sewer. The sewer entrance guide frame sat upon the hose and held it against the bottom of the sewer whenever the hose was in engagement with its rollers. The sewer entrance guide frame only extended below the bottom of the rollers by a single hose diameter, and since the lower end or the guide frame is submerged in murky water, the operation could not be observed when binding of the hose took place.
According to principles of the present invention, I have discovered that the sewer entrance guide should have a portion of its frame sitting on the bottom of the sewer to support the rollers above the bottom of the sewer by a distance that is greater than the diameter of the hose being fed into the sewer, and preferably at least one and one half hose diameters. Why this is necessary was not readily apparent, but since such a frame has had such a pronounced effect on the ease with which the hose is fed into the sewer and has eliminated the binding conditions which previously existed, it is theorized that the prior art hose guides have forced the hose down against the bottom of the sewer to locate the hose tight along the bottom arc of the sewer. It is theorized that pressure holds the section taunt against the bottom of the sewer from the point where it is confined between the lowermost roller and the bottom curvature of the sewer. It is believed that with the prior art guide, the hose did not conform to the rollers but extended out into the manhole where lateral force on the hose caused the hose to abut the sides of the frame and rotate it to thereafter keep the hose out of engagement with the rollers. Considerable difficulty has been experienced with the prior art devices in that the hose binds and does not feed into the sewer properly; and it is possible that the hose, when moved away from the rollers, even gets caught beneath the frame, particularly when the hose is fed laterally into the manhole. It has been thought by the prior art that the hose needed to be confined between the bottom of the sewer and the lowermost roller, and there has been no evidence to the contrary prior to the present invention.
I have made the discovery that the binding down in the manhole can be almost completely eliminated by providing feet on the frame of the sewer guide frame which raises the lowermost roller up off of the bottom of the sewer, so that the hose is not confined between the lowermost roller and the bottom of the sewer. Theoretically, tension on the hose should raise the guide clear of the bottom. Exactly how the feet correct the problem is not completely understood. In conjunction therewith, I provide a concave roller at the top of the manhole which will permit a controlled tensioning of the hose between the guide at the top of the manhole and the sewer guide at the bottom of the manhole. It is necessary that the hose be kept properly tensioned, and this is not always possible when it is manually fed into the upper end of the manhole opening.
FIGS. 1 and 2 of the drawings show a sewer entry guide constructed according to the principles of the present invention. The guide consists of a pair of arcuate upper frame members 20 having at least three, and preferably four, rollers 22 supported therefrom for horizontal rotation. The upper frame members 20 are positioned on opposite sides of the rollers, and their lower ends continue horizontally by a suitable distance for entering the sewer to be cleaned. The frame members 20 are connected together and are suitably held spaced apart at their lower end, as by U-shaped abutment 24 projecting from the top thereof to engage the top of a sewer when the frame is raised vertically into abutment therewith. The device also includes two arcuately shaped feet 26 which are connected at their upper ends to respective ones of the upper frame members 20. The feet 26 extend down below the lowermost roller 20 by a distance that is one and one half diameters of the hose with which it is to be used. This distance is maintained by a pair of appropriate spacers 28. The forward end of the feet 26, are, of course, connected to the forward end of the frame members 20, so that the feet 26 act as lateral guides for causing the hose to approach the center of the rollers as the hose slides down the feet toward the frame members 20. As previously indicated, the prior art devices had guides, but the prior art guides supported the lower roller at approximately one hose diameter above the bottom of the sewer.
FIGS. 3 and 4 of the drawings show a guide structure uniquely suited to guide the hose down a manhole for proper entrance into the sewer guide of FIG. 2. The manhole guide shown in FIGS. 3 and 4 generally comprises a pair of frame members 30 having spaced apart parallel portions 32 having a length that generally corresponds to a radius of a manhole ring. One end of each parallel portion 32 is adpated to generally overlay one side of a manhole ring, and the other end of each frame members 30 is bent laterally so that they diverge from each other at an angle of approximately 70 degrees with their ends terminating over the manhole ring. The ends of the diverging portions 34 have hook portions 36 therebeneath, and which are so constructed so as to slip under the internal flange 38 of the manhole ring. The parallel portions 32 have upwardly extending brackets 40 welded to their top edges. A wheel 42 having a concave periphery 44 is suitably journaled between the upper ends of the brackets 40 at such a location that a hydraulic hose passing over the wheel will generally be centered in the manhole. The diverging portions 34 also serve to guide the hose towards the concave periphery of the wheel 42 when the hose is tensioned. A threaded pin 46 is mounted horizontally beneath the frames 30 by means of a threaded nut 48 that is welded to a pair of transverse plate members 50. The pin, of course, is threaded into the nut 48, and an unthreaded portion of the pin 46 projects outwardly beyond the ends of the parallel portion 32, so that the pin can sit down upon the internal flange 38 of a manhole ring and simultaneously abut the vertical edge 52 above the internal flange 38 which normally surrounds a manhole cover. The pulling action of the hose causes the end of the pin 46 to engage the surface 52 and prevent the hooks 36 from being pulled off of the internal flange of the manhole ring, so that the pressure and tensioning of the hydraulic hose is utilized to keep the guide assembly in place. The manhole guide is easily installed after the hose has been threaded down the manhole by putting the diverging legs 34 underneath the hose and pushing the manhole guide assembly forwardly into position wherein the hooks 36 are caught onto the internal flange 38 of the manhole ring. The hose automatically moves down into the proper position over the wheel 42 and downward force on the assembly causes the threaded pin 46 to be caught between the internal flange 38 and the vertical surface 52 of the manhole ring.
Whereas the prior part devices have required man power to properly feed the hydraulic hose down into the manhole. It is a feature of the present invention that the tensioning be done by the braking action of the hose reel itself. To this end, the traverse mechanism 14 has been redesigned to carry two spaced apart rollers 54 having concave peripheries that are rotatable about horizontal axes spaced at an oblique angle relative to each other. Since the rollers have a concave periphery, they can be spaced apart by a distance slightly greater than the diameter of the hydraulic hose without having the hose remain out of contact with one of the rollers for any appreciable period. Tensioning of the hose against either one of the rollers will accurately guide the hose, and a suitable handle on the frame of the traverse mechanism 14 can be used to swing the traverse mechanism to either side of the center line of the hose reel, while the hose remains guided by its engagement with one of the concave rollers 54. In some instances, the hose may be fed off of the hose reel 12 when the arm 16 is swung laterally to one side thereof. In this case, the hose will be held up against the bottom of the outer upper roller 54. The traverse mechanism 14 may include a pair of pin rollers 56 positioned outwardly of the rollers 54, and may also include a pair of horizontal pin rollers 58 beneath the concave rollers 54. In most instances, however, it will be highly desirable, particularly where the hose is being retrieved, to cause the hose to extend from the traverse mechanism around a load sheave 60 about to be described.
The load sheave 60 is mounted for rotation about an axis parallel to the longitudinal axis of the vehicle 10 with one side of the wheel being supported generally tangent to the plane passing through the vertical center line of the hose reel. The periphery of the load sheave 60 is concave so as to properly guide the hose. The load sheave 60 is positioned rearwardly of the truck by a proper distance so that it will support the hose in approximately a straight line condition with the traverse mechanism 14 and the top of the hose reel. A slight bow in the hose as it moves through the traverse mechanism 14 is desirable to hold its engagement with the lower concave roller 54; and since the load sheave is held in a fixed position at approximately the center line of the hose reel, the traverse mechanism can be easily pushed from one side to the other to thread the hose onto and off of the hose reel. The load sheave 60 is mounted on a stub shaft 62 which is in turn welded to the end of a square tube 64 which telescopes into a larger square tube 66 that in turn is welded to the internal frame of the vehicle 10. The telescoping square tubes 64 and 66 have holes passing therethrough for receiving a pin 68 to lock the load sheave longitudinally of the vehicle at the appropriate position. Since it is necessary that the load sheave extend rearwardly from the vehicle by a considerable distance, the construction of the load sheave is such that the pin can be removed and the load sheave moved up against the frame of the vehicle during transporting of the vehicle.
The significance of the structure so far described will best be apparent from an understanding of how it operates. Instead of having a work crew feed the hose from the reel in a sweeping bend and center it down the manhole, it is possible with the structure of the present invention, to utilize the friction brake on the hose reel to keep the hose properly tensioned all the way from the hose reel to the hydraulic jet down in the sewer being cleaned. The tensioning of the hose over the load sheave 60, and manhole sheave 42, keeps the hose properly centered in the manhole and the guide sheave frame properly locked in position on the manhole ring. At the same time, the tensioning of the hose against one or more rollers 22 of the sewer entry guide 20 keeps the hydraulic hose loosely positioned off of the bottom of the sewer being cleaned. A uniform tensioning of the hose up off of the bottom of the sewer obviates binding with respect to the sewer entry guide frame. This allows the portion of the hydraulic hose that extends into the sewer being cleaned to be under the same tension as elsewhere and allows the nozzle to better center itself in the sewer being cleaned. A better nozzle action, therefore, is to be expected.
Whereas it was very difficult with the prior art to "reverse clean" the sewer by pulling the hydraulic hose out of the sewer under pressure. This is greatly facilitated with the structure of the present invention. Since the hose is under uniform tension all the way from the hose reel to the hydraulic jet, all possibility of hose being rubbed over sharp edges is obviated. The hose can be wound up on the hose reel using power to slowly and uniformly withdraw the hydraulic jet. In order to perform this operation, the operator need only stand at the traverse mechanism and guide it to opposite sides of the center line of the hose reel; and when the hose passes over the load sheave 60, the hose will in most instances be pulled down tight against an adjacent coil so that it traverses itself forward and back across the hose reel in a uniform retrieving action. This is not the case with the prior art where the hose had to be man handled as it was retrieved.
It will be apparent that the objects heretofore enumerated, as well as others, has been accomplished; and that there has been provided a new and improved system for hydraulically cleaning sewers which overcomes the numerous disadvantages of the prior art, and some of which have been discussed above.
While the invention has been described in considerable detail, I do not wish to be limited to the particular embodiments shown and described; and it is my intention to cover hereby all novel adaptations, modifications, and arrangements thereof will come within the practice of those skilled in the art, and which fall within the purview of the following claims.
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An improved system whereby a high pressure hydraulic hose can be unwound from a hose reel while under pressure, and moved laterally to a remote manhole, without manual restraint. The total system utilizes: an improved down the manhole sewer guide for the hose, a self-contained manhole feed frame which can be slid under the hose and which utilizes the pressure in the hose to lock it in place, a stationary rotary guide wheel positioned on one side of the hose reel, and an improved traverse mechanism which will accommodate lateral movement of the hose between the guide wheel and the hose reel.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is divisional of U.S. patent application Ser. No. 10/101,652, filed Mar. 20, 2002, which is a continuation-in-part of U.S. patent application Ser. No. 09/936,721, filed Dec. 19, 2001, which is a 371 of PCT/EP00/02407, filed on Mar. 17, 2000.
FIELD OF THE INVENTION
[0002] The present invention relates to an artificial urinary diversion device. More particularly, the present invention also relates to a suitable method for implantation of a artificial urinary diversion device.
BACKGROUND OF THE INVENTION
[0003] Among patients with urinary bladder disorder there are a plurality of findings which require removal of the patient's bladder. In this situation, a urinary diversion incorporating different types of reservoirs is generally required. So-called wet diversions are preferred, with direct urinary diversion through the ureters, which are implanted into the abdominal wall, or by insertion of a neutralized part of the intestine, in which the ureters are implanted and which is for its part implanted into the abdominal wall.
[0004] In both cases the urine is collected in a urine bag, which is attached to the orifice.
[0005] Alternatively, the ureters are implanted into the rectum or—more and more in the past several years—into replacement bladders, which are made of neutralized parts of the intestine.
[0006] These replacement bladders are either connected with the endogenous urethra or they are conducted out by creating an appropriate self-preserving occlusion mechanism at the abdominal skin, for example in the navel region.
[0007] Typical indicators for a replacement of the endogenous urinary bladder are advanced tumors of the urinary bladder, but there are also malformations, bladder impairments due to inflammation, as well as functional obstructions, such as for example obstructions by urinating, or development of bladder atrophies among paraplegics.
[0008] Thus, one of the objects of the present invention is to create an artificial urinary diversion system and a suitable method for implanting same which is adaptable to the different shapes of different persons, which shows the largest possible filling volume, and which allows for easy handling.
[0009] It is another object of the present invention to create an artificial urinary diversion system which is highly adaptable, and which without previous direct or indirect determination of the potentially available volume for such a system, facilitates as effective as possible a determination of the volume available in the patient during surgery, and thus utilization of this device therein.
SUMMARY OF THE INVENTION
[0010] In accordance with the present invention, these and other objects have now been realized by the invention of an artificial urinary diversion device containing a urinary bladder, an axial direction, and comprising at least one first portion having a first cross-sectional surface perpendicular to the axial direction and including at least one outlet, a second portion having a second cross-sectional surface perpendicular to the axial direction, and a third portion having a third cross-sectional surface perpendicular to the axial direction, and including at least one inlet for accommodating the urinary bladder, the second portion being arranged between the first portion and the third portion, the first and second cross-sectional surfaces being smaller than the third cross-sectional surface, and a dislocation device for sensing or controlling the artificial urinary diversion device. Preferably, the first, second and third portions comprise modular units, whereby each of the first, second and third portions includes a transitional surface permitting a continuous surface transition between the modular units.
[0011] In accordance with one embodiment of the artificial urinary diversion device of the present invention, the first cross-sectional surface is larger than the second cross-sectional surface.
[0012] In accordance with another embodiment of the artificial urinary diversion device of the present invention, the device includes fluid guidance means for guiding fluid from the urinary bladder through the third portion, the second portion, and the first portion.
[0013] In accordance with another embodiment of the artificial urinary diversion device of the present invention, the device includes an actuator for actuating the urinary bladder. Preferably, the actuator comprises a pump, and the pump is preferably disposed in the third portion. In a preferred embodiment, the pump comprises a telescopic device, and in another embodiment, the pump comprises a lever pump including two chambers. In yet another embodiment, the pump comprises a screw pump. Preferably, the screw pump is disposed in the first portion. In another embodiment, the screw pump includes at least one screw which can be moved laterally.
[0014] In accordance with another embodiment of the artificial urinary diversion device of the present invention, the device includes a sphincter mechanism. Preferably, the sphincter mechanism is disposed in the first portion.
[0015] In accordance with another embodiment of the artificial urinary diversion device of the present invention, the dislocation device includes control means. Preferably, the device includes a sphincter mechanism, and the control means controls the sphincter mechanism. In another embodiment, the device includes a pump, and the control means controls the pump. Preferably, the device includes secondary batteries, and the control means controls the recharge of the secondary batteries.
[0016] In accordance with another embodiment of the artificial urinary diversion device of the present invention, the device includes a sensor system for monitoring the filling level of the urinary bladder. In the preferred embodiment, the device includes signal means whereby the sensor system produces a signal when reaching a predetermined filling level of the urinary bladder. Preferably, the signal comprises an audible or a vibratory signal. Preferably, the sensor system is controlled by the nerves responsible for natural urinary bladder control.
[0017] In accordance with another embodiment of the artificial urinary diversion device of the present invention, the device includes a power supply. In a preferred embodiment, the device includes an external recharge device whereby the external recharge device cooperates with the power supply. Preferably, the external recharge device cooperates inductively with the power supply. In one embodiment, the power supply comprises secondary batteries integrated into the artificial urinary diversion device. In another embodiment, the power supply comprises primary batteries integrated into the artificial urinary diversion device. Preferably, the external recharge device is disposed in the dislocation device. In a preferred embodiment, the dislocation device includes a display for indicating the dislocation. Preferably, the display includes a level indicator. In a preferred embodiment, the dislocation device comprises an abdominal bandage and includes a separate control mechanism. In accordance with one embodiment, the dislocation device is integrated into a garment. In another embodiment, the apparatus includes an ultrasonic transmitter and a receiver device for controlling the display. Preferably, the ultrasonic transmitter and receiver device includes external Reed contacts, a Hall generator, and a charging current unit of measurement or a power sensor.
[0018] In accordance with another embodiment of the artificial urinary diversion device of the present invention, the device includes an actor system for executing the removal of urine from the artificial urinary diversion device.
[0019] In accordance with another embodiment of the artificial urinary diversion device of the present invention, the third portion is divided into two parts which can be separated from each other depending on the filling level of the urinary bladder.
[0020] In accordance with another embodiment of the artificial urinary diversion device of the present invention, the third portion includes either one or two inlets.
[0021] In accordance with another embodiment of the artificial urinary diversion device of the present invention, the device includes at least one anti-reflux valve. Preferably, the at least one anti-reflux valve is disposed in the third portion.
[0022] In accordance with another embodiment of the artificial urinary diversion device of the present invention, the device includes a fixing element. In a preferred embodiment, the device includes a dovetail joint, and the fixing element is connected with the artificial urinary diversion device by means of the dovetail joint. In another embodiment, the device includes guide-rail means whereby the fixing element can be removably included and locked at a predetermined position. Preferably, the guide-rail means is integrated into the third portion. In another embodiment, the fixing element comprises a splay or expanding element. In accordance with a preferred embodiment, the fixing element is entirely included therewithin. In another embodiment, the fixing element is composed of a biocompatible, elastic material, preferably silicone.
[0023] In accordance with another embodiment of the artificial urinary diversion device of the present invention, the device includes a first outline of a shape corresponding to a polynomial function of 6 th degree, wherein
F ( x )= A+a 1 x+a 2 x 2 +a 3 x 3 +a 4 x 4 +a 5 x 5 +a 6 x 6
in which 0<A< 2; 0<a 1 <8; −2<a 2 <0; 0<a 3 <1; −0,1<a 4 <0; 0<a 5 <0,003; and −0,00001<a 6 <0, within the domain in which 0<x<22.
[0024] In accordance with another embodiment of the artificial urinary diversion device of the present invention, the device includes a second outline of a shape corresponding to a polynomial function of 6 th degree, wherein
F ( x )= A+a 1 x+a 2 x 2 +a 3 x 3 +a 4 x 4 +a 5 x 5 +a 6 x 6
in which 0<A<2; 0<a 1 <8; −2<a 2 <0; 0<a 3 <1; −0,1<a 4 <0; 0<a 5 <0,003; and −0,00001<a 6 <0 within the domain in which 0<x<22.
[0025] In accordance with another embodiment of the artificial urinary diversion device of the present invention, the first, second and third portions are formed integrally. Preferably, the third portion includes an originating electric link to a portion of the dislocation device which is subcutaneously implanted.
[0026] In accordance with one embodiment of the artificial urinary diversion device of the present invention, the actor is controlled by an encoded signal.
[0027] In accordance with the present invention, a method has also been provided for implanting the artificial urinary diversion device discussed above, the method including the steps of selecting a modular unit which has an external contour corresponding to the artificial urinary diversion device; exchanging the modular unit for one of the first, second or third portions to obtain a matching implantable artificial urinary diversion device; assembling the artificial urinary diversion device in correspondence with the modular unit; and implanting the assembled artificial urinary diversion device.
[0028] According to the present invention, the second area, which is arranged between the first and the third area, includes a cross-sectional surface which is smaller than the cross-sectional surface of the third area. In this manner, a shape is provided, which can be adapted to almost any patient, and more particularly, the largest possible filling volume can be provided, namely by simultaneous consideration of various medical preconditions, such as for example the arteries and the intestine that, after the operation, pass laterally to the second area and on which no pressure must be put. Attention must be paid to the fact that, with a person who is standing erect, the third area is arranged above the second area and the first area. For example, if the first area shows a larger cross-sectional surface than the second area, a so-called constriction will also be provided in the second area, which is necessary for the bypassing arteries and/or the intestine and the kidneys, and a positional fixing with the first area is possible, for example, at the pubic bone (Symphysis Pubica). With the dislocation device, according to the present invention, which may, for example, be a device for dislocation supervision or dislocation display, handling of the device will be eased during permanent use thereof. By utilizing the dislocation device, on the one hand, it is possible to indicate the position for the optimal wireless transcutaneously transfer of performance or, on the other hand, to describe a support when correcting the positioning in case of an initial false placing, as each dislocation leads to a loss of performance.
[0029] With the method according to the present invention, implantation of an artificial urinary diversion system is provided, which, due to the provision of an element or module which possesses the external contour of the artificial urinary diversion system, and which can be assembled in a modular design, protection of the patient and of the resources is possible. Therefore, in a first step in the operating room, a plurality of sample pieces, i.e., modules of the element, are assembled to an optimally suited urinary diversion system for the patient. Thus, especially with regards to hygiene, a method is provided which only requires sterilization of the particular modules of the element, and not, in the case of mismatching, modules with a highly complicated technique inside.
[0030] If the first, second and third areas are modularly compounded or rendered modularly compoundable, and if the respective transition surfaces between the individual areas are coordinated in a desired manner, a continuous transition results, and the advantage will be achieved that, according to the respective spatial condition of the patient, the individual areas of the urinary diversion system can be compounded and thus, it will be possible to take optimal account of the anatomical conditions of the patient.
[0031] If fluid guidance means are provided, which extend from the urinary bladder to the outlet in the first area, this corresponds to a large extent to the natural anatomy, which means, that among a person who is standing erect, the lowest, first area can be connected directly with the existing urethra, without using additional connection elements between the urethra and the outlet in the first area, which could possibly cause further medical complications.
[0032] If an actor or an actuator or a pump is provided in the third area, there is then no need to provide an external pump, and, in view of the shape selected, the first and second areas are not negatively influenced. Furthermore, in the embodiment in which an actuator or a pump is provided in the third area, the third area, which is optimally embodied, can now be most likely to have the most space for the integration of a pump without greatly or negatively influencing the shape.
[0033] If the pump is formed as a telescope device, almost the total volume of the third area can now be advantageously used for filling the urinary bladder. Laboratory experiments have already shown that almost the entire urinary bladder can be emptied with a telescope device, without leaving any sediment in the urinary bladder.
[0034] If the pump is formed as a lever pump, no complex mechanics are required to be integrated therein, such as for example for the use of a telescope device in the third area.
[0035] If the pump is formed as a screw pump, another advantage is that almost the entire volume of the third area can now be used for the urinary bladder. In addition, by using a screw pump, the screw pump can pulverize possible smaller urine crystals, so that these pulverized crystals can also be passed through a stenotic urethra.
[0036] If additionally a screw pump is also arranged, such that it may possibly be displaced laterally to the fluid tube or duct, an inlet and a lavage of the artificial urinary diversion system can now be provided without difficulty, since the fluid tube can now be opened by moving the screw. This result concerning the inlet and the lavage of the artificial urinary diversion system can be very important in the field of spectroscopic examinations, for example.
[0037] If a sphincter mechanism is preferably provided in the first area, almost total control of the urinary continency is now possible. The control of the sphincter mechanism can, for example, also be initiated externally.
[0038] If, in addition, a control system is provided, which regulates the sphincter mechanism, such a control system, which is also able to assume further procedures, can also regulate opening and closing of the sphincter.
[0039] If, a sensor system is provided for controlling the filling level of the urinary bladder, the patient will be given a high degree of safety by using the artificial urinary bladders. That is, the patient does not have to void the urinary bladder regularly and in short intervals, but can instead integrate with everyday life in the usual way. If either a sound signal or a seismic signal, which will be produced at a certain filling level of the bladder, is sent to the concerned person, the person can operate normally in everyday life. However, it is also noted that, if at least a security regulation is installed in the sensor system, then, if a certain period of time, for example 8 to 12 hours, is exceeded, the person is signaled to void the bladder, independent of the filling level of the bladder. Furthermore, by controlling the filling level of the artificial bladder security is provided, which is oriented for specific physiological marginal conditions. Thus, the artificial urinary diversion system can operate similarly to the function of the natural urinary bladder. Thus, with this urinary diversion system similar to the natural process, the body first signals the person that the urinary bladder should be emptied, then the bladder will be opened, the urine will be pressed out or squeezed out, and the bladder will be closed again.
[0040] If the sensor system is controlled by the nerves responsible for the urinary bladder, an almost natural feeling will be given to the concerned person by means of this neurological solution, and therefore an exogenous signal, such as that produced by a sound signal, or a seismic signal, will not be necessary.
[0041] If a power supply is additionally provided in the urinary diversion system, a compact urinary diversion device can be provided, which can, for example, first be integrated into the artificial urinary diversion system. However, the power supply can also be arranged separately, near the urinary diversion system in the patient, if, for reasons of space, a third area must be used which does not allow for an additional power supply.
[0042] If an external recharge device provides the power supply, the urinary diversion system can be provided with power for almost a lifelong period. Charging of the counterpart of the external recharge device can be effected by the adapted counterpart, which is charging wireless transcutaneously at an adapted main support location, which is implanted subcutaneously.
[0043] A simple power transfer can, for example, be achieved by the recharge device cooperating inductively with its counterpart, with power being transferred inductively at frequencies which are tolerated by the body, for example 30 kHz.
[0044] If the power supply is composed of secondary batteries, the urinary diversion system will optimally cooperate with the recharge device.
[0045] If the power supply is comprised of primary batteries, which are integrated into the urinary diversion device, the urinary diversion device will work without any continuing maintenance and the person concerned does not have to worry about the power supply.
[0046] If the dislocation unit is integrated into the recharge device, handling is simplified and, when the recharge device is out of place, such false placement will be documented. This is quite important, because, in case of inductive, capacitive or other wireless transmission of performance data from the outside into the human body, the external and internal transmitter components must be optimally led together in the appropriate position. In this manner, direct positioning can be shown digitally by means of a yes/no display or an optimal/non-correct display.
[0047] If the dislocation unit includes a display unit for indicating dislocation, preferably a level display, the extent of longitudinal dislocation and the extent of rotational dislocation, particularly by means of a level display, are shown.
[0048] If the dislocation unit is developed as an abdominal bandage with a separate operating element, a compact system is provided, which can be worn partially invisibly and permanently correctly positioned.
[0049] If the dislocation unit is integrated into a garment, the user can comply with his habits, without being visibly singled out.
[0050] Identification of improper positioning can be effected alternatively, or it can be combined by means of an ultrasonic transmitter and receiver with an attaching telemetric data-signal transmission from the body, or an external reed contact, which react with a subcutaneously implanted magnetic field of, for example, at least two permanent magnets, or by means of a Hall generator or an agitated Hall sensor, which reacts with implanted magnetic or field-producing components, or by means of a charging-current measurement, whose correct positioning of the transmission media results in a maximum charging current, as lateral deviations in any direction and in rotation diminish the ideal position of the charging current, whereby by measuring and indicating the charging current correct positioning can be determined, or this can be done by means of a current sensor.
[0051] If an actor system is also integrated into the urinary diversion device, once again a completely independent system can be provided, which only needs to be connected at the inlets or outlets with functional structures of the patient's urinary diversion system, and which can be implanted as one compact part.
[0052] It is also pointed out that where necessary the power for the actor system and/or the sensor system can be transferred wirelessly transcutaneously by placing a suitable transfer device onto the skin. However, it is also necessary in that case that controlling and providing can also be executed by primary batteries as an additional power source. It is also possible that the total control and sensor system can be interrogated, and initiated externally telemetrically.
[0053] If the third area is constructed bipartite or in two-part form and dependent on the filling level of the urinary bladder, one part is able to move away from the other part, it is also possible to flexibly adjust the size of the urinary bladder and the filling level, in accordance with the patient's requirements.
[0054] If the urinary diversion device includes two inlets in the third area, so that each ureter can be connected with the artificial urinary diversion system, it will not be necessary to provide a further separate additional element, for example in a Y-shape, which can be used if it is advantageous that the urinary diversion device only has one inlet.
[0055] By providing one or more anti-reflux valves in the third area, reflux of the urine into the kidney can be stopped. This also prevents possible ascent of bacteria from the bladder up to the kidney.
[0056] If a fixing element is provided, it is then easy to arrange and fix it in the human body.
[0057] If the fixing element is connected with the urinary diversion device by means of a dovetail joint, a tight or leak-proof connection can be constructed, and the fixing element can be retained in the body, in order to be later connected at the right place with the urinary diversion device.
[0058] If the fixing element is movably fixed by means of a guidance system, the urinary diversion device can, according to the anatomy of the person concerned, be optimally arranged and fixed. If the guide-rail system is also integrated into the third area, there are no rails available that are protruding from the third area, which could possibly adversely influence arrangement in the human body, or cause any functional or spatial inconvenience.
[0059] If the fixing element includes a splay or expanding element, which may, for example, widen after implanting into the guide rails, the possibility of a simple connection is provided, guarantying a particular compatibility by the complete integration of the splay element into the fixing element.
[0060] If the fixing element is formed with a biocompatible material, such as silicone, a well-tolerated material is provided, and in addition the elasticity of the silicone and other such materials are utilized due to the splay movements of the splay element.
[0061] If the actor is controlled by an encoded signal, a malfunction of different artificial urinary diversion systems is impossible, thus avoiding any unintentional voiding of different artificial urinary diversion systems.
BRIEF DESCRIPTION OF THE DRAWINGS
[0062] Referring to the following detailed description, which refers to the drawings, the artificial urinary diversion system of the present invention is described in detail, as follows:
[0063] FIG. 1 is a side, perspective, schematic view of the artificial urinary diversion system of the present invention;
[0064] FIG. 2 is side, elevational, a sectional view of the artificial urinary diversion system shown in FIG. 1 , taken along line II-II thereof;
[0065] FIG. 3 is a top, elevational, view of the urinary diversion system shown in FIG. 1 ;
[0066] FIG. 4 is a bottom, elevational view of the urinary diversion system shown in FIG. 1 ;
[0067] FIG. 5 is a side, perspective, fragmented view of the urinary diversion system shown in FIG. 1 separated into single areas;
[0068] FIG. 6 is a side, elevational, sectional view of the arrangement of the urinary diversion system of the present invention in a human body;
[0069] FIG. 7 is a front, elevational view of the urinary diversion system shown in FIG. 6 ;
[0070] FIG. 8 is a top, elevational view of the urinary diversion system shown in FIG. 7 , taken along line VII-VII thereof;
[0071] FIG. 9 is a graphical representation showing one executed polynomial function of 6 th degree regarding the top surface outline of the urinary diversion system in accordance with FIG. 1 ;
[0072] FIG. 10 is a graphical representation showing the top-view silhouette of the urinary diversion system shown in FIG. 1 , relating to the polynomial function of 6 th degree referred to in FIG. 9 ;
[0073] FIG. 11 is a side, elevational, schematic view of an embodiment of the fixing element used in accordance with the present invention;
[0074] FIG. 12 is a schematic view of the dislocation unit of the present invention; and;
[0075] FIG. 13 is a side, perspective view of one embodiment of the dislocation unit of the present invention.
DETAILED DESCRIPTION
[0076] A preferred embodiment of the urinary diversion system explained in FIG. 1 includes a first area A, a second area B and a third area C, with the cross-sectional surfaces (illustrated hatched) that are perpendicular to the axial alignment of the urinary diversion device of the first, second and third areas, being constructed such that the cross-sectional surface Q 1 of the first area A is larger than the cross-sectional surface Q 2 of the second area B and the cross-sectional surface Q 3 of the third area C is in each case larger than the cross-sectional surfaces of the first and second areas. In addition, the first area A includes an outlet 3 and the third area C includes two inlets 5 for the urethras, which come from the respective kidneys.
[0077] The first area A of the urinary diversion system includes at its bottom surface 7 an increasing area D, with the shape possibly being linear, arched, concave or convex, dependent upon the patient's anatomical conditions for the urinary diversion system hereof. In FIG. 1 it can clearly be seen that the second area B, which is arranged between the first area and the third area, is to be regarded as a constriction, with arteries being led by laterally to its surfaces 9 . The third area C, which comprises a urinary bladder, is shaped voluminously enough to allow for filling as much as possible. The two inlets for the renal urethra are provided at the front side of the third area.
[0078] FIG. 2 illustrates a lateral sectional view according to intersection II-II of FIG. 1 . With this sectional view it can clearly be seen that the urinary diversion device 1 presented in FIG. 2 shows the top-side of a first outline K 1 . Here, in contrast to FIG. 1 , the elevation of the second area B to the bottom surface 7 of the first area A is more clearly seen. In this embodiment, a curved or curvilinear elevation is shown. This curved elevation serves to be brought into contact, for example, with the pubic bone and thus makes positional fixing possible. It can also be seen in FIG. 2 that below the third area so-called guide rails 13 are provided, in which a fixing element (not shown) can be inserted. At this point, special attention should be drawn to the fact that a protruding of the guide rails may, for example, be avoided by complete integration into the third area.
[0079] FIG. 3 illustrates a top view of the urinary diversion system 1 and a second outline K 2 in accordance with FIG. 1 , with the constriction caused by the second area B being clearly visible, such that the arteries can be led by laterally of the side surfaces 9 . The relative proportions, which are shown between the first, the second and the third area, are also clearly visible.
[0080] FIG. 4 shows a bottom view of the urinary diversion system 1 . The provided guide rails 13 for the fixing element are clearly indicated.
[0081] FIG. 5 illustrates the urinary diversion system 1 , with its individual areas, i.e. first, second and third area, illustrated separately.
[0082] At this point it should be noted that the division or sectioning into a first area, a second area and a third area sets forth a preferred embodiment hereof. The urinary diversion system can also be provided with only two areas or as an integral entity. On the other hand, it is also possible to provide more than three areas, which can be divided separately with more areas of the increased adapting variation being taken into account.
[0083] FIG. 6 illustrates, for example, arranging of the urinary diversion system. The first area A borders on the pubic bone, with the fixing element, which is moveably includable in the guide rails, being fixed, for example, at the respective places in the abdominal cavity.
[0084] FIG. 7 shows a front view for further illustration of arranging of the urinary diversion system hereof.
[0085] FIG. 8 is a top view, with the body section being above the section of said urinary diversion system.
[0086] FIG. 9 is, for example, a fit curve of the polynomial form f(x)=a 6 x 6 +a 5 x+a 4 x 4 +a 3 x 3 +a 2 x 2 +a 1 x+a, i.e., a polynomial of 6 th degree, which has been adapted to the first outline. The parameters used for this adaptation are a 6 =−9·10 6 ; a 5 =0,006; a 4 =−0,014; a 3 =0,1638; a 2 =−0,9319; a 1 =2,6778 and a=0,8452. However, it turned out that within a domain of 0≦X≦22, the coefficients a 1 to a 6 in the domains 0<A<2; 0<a 1 <8; −2<a 2 <0; 0<a 3 <1; −0,1<a 4 <0; 0<a 5 <0,003 and −0,00001<a 6 <0 within a domain of 0<x<22 can be taken.
[0087] FIG. 10 illustrates a top view of the half of a second outline, which has also been approximated with a polynomial of 6 th degree. The parameters used for this were a 6 =1·10 −5 ; a 5 =0,008; a 4 =−0,0198; a 3 =0,221; a 2 =−1,2703; a 1 =3,9521 and A=1,2557. It has also been determined that these coefficients can also be taken in the domains 0<A<2; 0<a 1 <8; −2<a 2 <0; 0<a 3 <1; −0,1<a 4 <0; 0<a 5 <0,003; and −0,00001<a 6 <0 within a domain of 0<x< 22 , for adapting the respective second outline. To illustrate that FIG. 10 is a top view, the first outline and the fitted curve have been reflected at y=0 at the x-axis of the diagram.
[0088] FIG. 11 illustrates a fixing element 15 with a front area F, which can be introduced into the guide rails of the urinary diversion system, and an end area E, which can, for example, be pressed by hand.
[0089] Inside of the fixing element 15 there is a splay element (illustrated dashed), which is, due to the upright side surfaces 19 A to 19 D, taken along with the elastically formed fixing element 15 so that, for example, when impacting on the end area, the arms of the splay element 17 in the front area also move towards each other, and take the elastic material of the fixing element 15 with them.
[0090] Thus, the fixing element 15 can be narrowed such that it can be included between the two guide rails 13 . After introduction, the fixing element 15 will be released, so that, due to the elasticity of fixing element 15 , the front area F will return to its original shape, and a press fit/tight fit may be achieved with the side surfaces of the guide rails. If the fixing element 15 shall now be moved within the guide rail 13 , it is only necessary to re-press or re-contract the end area E, in order to open the press fit of the side surfaces of the front area F. The slots or openings 21 in the fixing element 13 serve for being tightly led by the guide rails when the position of the fixing element is to be re-aligned.
[0091] Thus, with this fixing element 15 the urinary diversion device can be suitably arranged before its final arranging and the fixing element can be fixed at the corresponding position in the abdominal cavity.
[0092] Due to this additional provision, which is providing a fixing element that is separate from the urinary diversion system, it is also possible to pre-fix the fixing element at places difficult to access for fixing a fixing element, and to then introduce it into the urinary diversion device.
[0093] Instead of the screw pump, the pump using a telescope device, and the lever pump, all other types of pumps are imaginable for squeezing the urine, particularly a membrane pump or a gear pump.
[0094] The cross-sectional surfaces Q 1 , Q 2 and Q 3 can be different geometrical surfaces, such as quadratic, rectangular, trapezoidal, round, oval, elliptical or any other combination thereof.
[0095] Exemplary for the block diagram, FIG. 12 shows electrical circuitry for the urinary diversion system with an external recharge unit and a dislocation unit. On the left side of the separating line A, the components of the recharge unit of the external power supply or of the dislocation unit are illustrated. On the right side of the separating line A, the components, which are linked to or integrated into the urinary diversion device are shown. In this embodiment, display of the dislocation is effected by an electronic evaluation of the Hall sensors, which are connected with the charging connection by means of a subcutaneous coil. The display of the charge status can, if possible, be effected optically or acoustically. The subcutaneously arranged components contain a charging connection, which is connected to the accumulator, when it is signalized by means of a control system signaling that the voltage has, for example, decreased for more than 6 volts, or it is signalized by means of a separate charge-status signal that the charging shall be effected. The charging connection is connected with a data-sender provider, which can, for example, indicate by means of the charging current if a dislocation is present. The control system particularly controls the status, when the consumer requires energy.
[0096] FIG. 13 shows an embodiment of a dislocation unit as an abdominal bandage with separate control, with the control containing a display for the longitudinal dislocation and for example a display for the rotational dislocation, preferably a level indicator. Basically, the control contains a longitudinal and rotational mobility possibility, which is relative to the fixing element, in this case a belt, in order to optimally position the dislocation unit. Furthermore, the control contains interrogation keys, by means of which it is possible to interrogate the recent operating state of the subcutaneously contained component. Furthermore, there is an LED display for the interrogation keys, with additional fix display modes being able to be made by means of the LED display.
[0097] Finally, concerning the spectroscopic examinations, it is noted that for the urinary diversion system, an emergency supply must be provided among all solutions of pumps, valves and anti-fix valves. This means that all artificial system components, such as valves, pumps, etc. have to be opened easily and to be easily movable or evadable. With this measure, the urinary diversion system will meet current medical standards.
[0098] Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims.
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An artificial urinary diversion device containing a urinary bladder is provided including first, second and third portions having respective cross-sectional surfaces such that the second portion is disposed between the first and third portions, and the first and second cross-sectional surfaces are smaller than the third cross-sectional surfaces, and a dislocator for sensing or controlling the artificial urinary diversion device.
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BACKGROUND OF THE INVENTION
The invention relates to a movement detection circuit for a PAL television signal containing a luminance signal and a chrominance signal having two quadrature components u(t) sin wt and ±v(t) cos wt, this movement detection circuit comprising a picture delay circuit.
U.S. Pat. No. 4,064,530 discloses a movement detection circuit of the above-described type wherein the input and output signals of a picture delay circuit are compared with each other after inversion of the chrominance signal in the delayed signal. It has been found that with such a movement detector it may happen that movement is detected in a still picture, due to crosstalk from the luminance signal to the chrominance signal.
SUMMARY OF THE INVENTION
The invention has for its object to provide a movement detection circuit for a PAL-television signal wherein the crosstalk from the luminance signal to the chrominance signal cannot produce a faulty indication that there is movement in a still picture.
According to the invention, a movement detection circuit of the type set forth in the opening paragraph, is characterized in that the movement detection circuit comprises a demodulation circuit for the chrominance signal, a combining circuit and a filter circuit to obtain a signal of the shape (u(t)-u'(t))±(v(t)-v'(t)), wherein u'(t) and v'(t) are demodulated chrominance signal components which are delayed relative to u(t) and v(t) by a time delay provided by the picture delay circuit, the demodulated single sideband components in this signal being suppressed and this signal being conveyed through an absolute value-producing circuit.
By effecting, in accordance with the invention, the movement detection on the demodulated chrominance signal, it has been found to be possible to prevent a faulty movement indication from occurring, because of the special properties of the PAL signal.
DESCRIPTION OF THE DRAWING
The invention will now be further described by way of example with reference to the accompanying drawing.
In the drawing
FIG. 1 illustrates, by means of a block diagram, a movement detection circuit in accordance with the invention; and
FIG. 2 also, illustrates, by means of a block diagram, a further possible movement detection circuit in accordance with the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In FIG. 1 there is applied to an input 1 a PAL television signal which can be written as the sum of a luminance signal y(t) and a chrominance signal comprising two quadrature components u(t) sin wt and ±v(t) cos wt, so
y(t)+u(t) sin wt±v(t) cos wt (I).
In a band-pass filter 3 those components which are outside the frequency range in which the double sideband portion of the chrominance signal is located are removed from this television signal. As a result thereof the only remaining portion of the luminance signal is a high-frequency portion h(t). Therefore, a signal
h(t)+u(t) sin wt±v(t) cos wt (II)
appears at an output 5 of the band-pass filter 3.
This signal is applied to an input 7 and to an input 9 of synchronous demodulators 11 and 13, respectively, and also to an oscillator circuit 17 via a switch 15. The switch 15 allows only the color synchronizing signal to pass to the oscillator circuit 17, which generates signal of the chrominance subcarrier frequency by means of this color synchronizing signal, and produces a signal sin wt, at an output 19 and a signal, cos wt, at an output 21.
These signals are applied to the synchronous demodulators 11 and 13, respectively, which together form a demodulation circuit.
The synchronous demodulator 11 supplies at an output 23 a signal of the shape
h(t) sin t+1/2u(t) (III)
wherein the polarity of the demodulated color difference signal u(t) remains equal from line to line, while the synchronous demodulator 13 produces at its output 25 a signal of the shape
h(t) cos wt±1/2v(t) (IV)
wherein the polarity of the demodulated color difference signal v(t) changes from line to line.
The signals at the outputs 23 and 25 of the synchronous demodulators 11 and 13 are applied to a substracting circuit 27 and to an adder circuit 29. A signal
h(t)(cos wt-sin wt)-1/2u(t)±1/2v(t) (V)
is then formed at an output 31 of the subtracting circuit 27 and a signal
h(t)(cos wt+sin wt)+1/2u(t)±v(t) (VI)
is formed at an output 33 of the adder circuit 29.
The signal at the output 31 of the circuit 27 is applied, via a delay circuit 35 producing a delay of one picture period, or two field periods, to an input 37 of a combining circuit 39, which acts as an adder circuit. The signal at the output 33 of the adder circuit 29 is applied to an input 41 of the combining circuit 39.
The signal at the input 37 of the combining circuit 39 has the shape
h(t-τ)(cos w(t-τ)-sin w(t-τ))-1/2u(t-τ)±1/2v(t-τ) (VII)
wherein
τ=40 ms.
It holds for a PAL signal that w=2πf, wherein f=283.7516 f h , f h being the horizontal deflection frequency. That is to say, a line deflection period comprises 283.7516 chrominance subcarrier periods and consequently a picture period comprises ##EQU1## chrominance subcarrier periods.
From the above it follows that:
cos w(t-τ)=cos (wt+π/2)=-sin wt
sin w(t-τ)=sin (wt+π/2)=cos wt
In addition, the v(t-τ) signal has a polarity which is the opposite of the polarity of the signal v(t), as the number of horizontal deflection periods per picture is odd.
Formula (VII) can therefore be written as
h'(t)(-sin wt=cos wt)-1/2u'(t)±1/2v'(t) (VIII)
wherein
h'(t)=h(t-τ)
u'(t)=u(t-τ)
v'(t)=-v(t-τ)
At an output 43 of the combining circuit 39 a signal of the following shape is produced
(h(t)-h'(t)) (cos wt+sin wt)+1/2(u(t)-u'(t))±1/2(v(t)+-v'(t)) (IX)
In this formula (IX) the terms (h(t)-h'(t)), (u(t)-u'(t)) and (v(t)-v'(t)) are all differential terms, that is to say a signal can only be produced at the output 43 of the combining circuit 39 when a difference occurs in one of these terms, so at the occurrence of movement. The cross-talk-induced portion (h(t)-h'(t)) (cos wt+sin wt) of the luminance signal can only produce a movement indication when movement does indeed occur in the luminance signal.
The sign of the signal at the output 43 of the combining circuit 39 is removed by an absolutely-value producing circuit 45 and this signal is further applied to an input 47 and also, via a delay circuit 49 producing a delay equal to one horizontal deflection period, to an input 51 of an adder circuit 53. This prevents equal or opposite changes in the signals u and v from only producing a movement indication every other horizontal deflection period.
It will be obvious that the circuit 49, 53 may be omitted in the majority of cases.
If, in the substracting circuit 27 the signal v(t) is substracted from u(t), instead of u(t) from v(t) as described above, then the combining circuit 39 must be in the form of a subtracting circuit in which the signal at the input 37 must be subtracted from the signal at the input 41.
The band-pass filter 3 described above may also have for its object to suppress the single sideband components of the chrominance signal. If so desired, this suppression may however also be effected in the demodulated signals.
It will further be obvious that the sign of the output signals from the demodulators 11 and 13 can be changed by shifting the phase of the relevant signal at the output 19 or 21 of the oscillator circuit 17 through 180°. This change in sign must then be taken into account in the remaining portion of the circuit. Circuits of such a type are also assumed to be within the scope of the invention, and also circuits in which, for example, the delay circuit 35 is replaced by two delay circuits provided at the inputs of the subtracting circuit 27 or, for example, circuits in which more than two synchronous demodulators are used to produce signals of the desired polarities. FIG. 2 shows an embodiment of the last-mentioned implementation, the picture delay circuit being included in a portion of the circuit in which the signal has not yet been demodulated.
In FIG. 2 corresponding components are given the same reference numerals as in FIG. 1. For the description reference is made to the description given with reference to FIG. 1.
In FIG. 2 the demodulation circuit comprises in addition to the synchronous demodulators 11 and 13, two further synchronous demodulators 55 and 57, respectively, the respective inputs 59 and 61 of which are connected to an output of the picture delay circuit 35 which is connected to the input 1, and respective outputs 63 and 65 of which are each connected to an input of the combining circuit 39, two further inputs of which are connected to the outputs of the demodulators 11 and 13.
The synchronous demodulator 55 receives the signal sin wt from the output 19 and the synchronous demodulator 57 receives the signal cos wt from the output 21 of the oscillator circuit 17 as reference signals.
In a comparable manner as shown in FIG. 1, it can be demonstrated that the synchronous demodulators 11, 13, 55, 57 supply the following signals:
From the output 23 of the demodulator 11
1/2u(t)+h(t) sin wt (X)
From the output 25 of the demodulator 13
±1/2v(t)+h(t) cos wt (XI)
From the output 63 of the demodulator 55
±1/2v-(t)+h'(t) sin wt (XII)
From the output 65 of the demodulator 57
1/2u'(t)+h'(t) cos wt (XIII)
(X)+(XI)-(XII)-(XIII) now results in
1/2(u(t)-u'(t))±1/2(v(t)-v'(t))+(h(t)-h'(t))(sin wt=cos wt)
So the combining circuit 39 must add together the signals at the outputs 23 and 25 of the demodulators 11 and 13 and must subtract therefrom the signals at the outputs 63 and 65 of the demodulators 55 and 57 to render it possible for this combining circuit to supply from its output 43 the same signal as in the example of FIG. 1.
The filter circuit is now provided by a low-pass filter 67 connected to the output 43 of the combining circuit 39, this low-pass filter 67 suppressing the demodulated single sideband components.
The absolute-value producing circuit 45 is connected to an output of this low-pass filter 67.
Also here it holds that the sign of the output signals of the demodulators 11, 13, 55 and 57 can be influenced by the choice of the polarity of the reference signal and that in the majority of cases, the circuit 49, 53 can be omitted.
It will further be obvious that also circuits by means of which signals of the shape (XI) are obtained in which the signs of the three terms are difference than described herein must be considered to be within the scope of the invention.
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Movement detection in a PAL television signal is effected on that portion of the television signal which is located within the chrominance signal band. This portion (obtained via 3) is demodulated into color difference signals (11, 13) which are added (29) and subtracted (27). The subtracted signal is delayed for one picture period and combined (39) with the added signal. Then the absolute value is produced (45), so that a signal is obtained which only reports movement and does not interpret crosstalk from the luminance signal of a still picture to the chrominance signal as movement.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to rescue apparatus and, more particularly, to a self-propelled rescue apparatus for deploying a "life-line" and life-support item to a distressed target located a substantial distance from the launching site.
2. Description of Prior Art
It has long been a problem when attempting to rescue people, especially a person who has fallen overboard from a boat, to be able to launch a line from the rescuer to the person in distress. This problem has been especially evident when the rescue apparatus, in its simplest form, involves hand throwing a life line or other rescue device to the person in distress. Clearly, such apparatus inherently depends on the strength and skill of the rescuer and, at best, suffers from a severe distance limitation. Even more advanced apparatus which rely upon firing a projectile comprising life saving devices have had their limitations as to the distances the rescue device can be projected and because of safety factors involved with the launching platforms used for firing the projectiles.
In the field of mechanized rescue apparatus, it has been the general practice to employ projectiles, with attached life-lines which are fired in the direction of the distressed person. The projectiles historically have relied upon launching devices, such as modified rifles, grenade launchers and harpoon launchers. Although such devices have been useful, they have not proven to be entirely satisfactory under all conditions, generally having been designed for large commercial or military vessels (as evidenced by one system that uses a fuel driven propulsion rocket motor as a thrust source). Additionally, they do not lend themselves to general public use due to the inherently dangerous environment associated with the launching devices which employ gun powder, volatile fuel, or similar charges to propel the life saving projectile. They are also limited in terms of the distance that a projectile can be fired from a launcher.
It will be appreciated then, that there exists a need for a simple means of launching rescue devices to distressed people in life threatening situations at great distances from the rescuer, while at the same time providing a safe launching platform, free from dangerous fuels, explosives, or other firing mechanisms. Moreover, it is desirable to do so with relatively low cost apparatus that comprises all reusable parts which dramatically reduces on going operational costs.
SUMMARY OF THE INVENTION
Briefly, and in general terms, the present invention provides a safe, reliable rescue apparatus for deploying a life-line with a life-support item at one end to a distressed target at a substantial distance from a rescuer. This is accomplished by apparatus that incorporates a self-propelled missile which is releasably mounted on a launcher connected to the other end of the life-line and which, upon activation, carries the life-support item and life-line from the launcher to the location of the distressed target.
In a more detailed aspect of the invention, the launcher is adapted to be hand-held and the missile includes a cartridge of pressurized gas that serves as the missile propellant. Mounted on the missile is a container that releasably contains the life-support item adapted to be released automatically at the location of the target. For economic and convenience reasons, the gas cartridge preferably is rechargeable.
In a preferred embodiment of the invention, the rescue apparatus is especially adapted for rescue of a person in distress in the water. The life-support item then constitutes a flotation device that is carried initially within the container on the missile in a collapsed condition. Upon water contact, the flotation device is deployed from the container and expanded for supporting the distressed person and enabling rescue by retrieval of the life-line. To aid in the rescue process, a beacon is also carried by the missile and arranged to be illuminated upon contact with the water.
These and other features and advantages of the invention will appear in the following detailed description of the preferred embodiment, read in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of rescue apparatus embodying the invention in a condition in which it is ready to be utilized;
FIG. 2 is a cross-sectional view taken on line 2--2 of FIG. 1;
FIG. 3 is an enlarged, partial view taken within circle 3 of FIG. 2, depicting the apparatus of the invention immediately after initiation of a launch;
FIG. 4 is a cross-sectional view taken on line 4--4 of FIG. 3;
FIG. 5 is a perspective view of a flotation device which is part of the disclosed embodiment, in a deployed condition, the flotation device being shown in collapsed condition in FIG. 1 and FIG. 2;
FIG. 6 is a partial cut-away view of the flotation device inflation mechanism;
FIG. 7 is a pictorial rendition of the rescue apparatus of FIG. 1 being deployed; and
FIG. 8 is a partial cut-away perspective view of a missile recharging adapter depicting how it is affixed to the rescue apparatus and a standard compressed air tank for recharging purposes.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, and particularly to FIG. 1, there is shown a self-propelled rescue apparatus 10 of the present invention. The rescue apparatus 10 includes a hand-held launcher 12 for a self-propelled missile 14 that carries a life-support item, such as an inflatable harness 16, with a flexible life-line 18 attached thereto, to a distressed target, such as a person who has fallen overboard from a boat. A typical rescue scenario is depicted in FIG. 7, where the missile 14 has been aimed and launched by a rescuer 20 to a person 22 in distress in the water a substantial distance away from the rescuer. The missile 14 delivers to the person 20 the flexible life-line 18, the inflatable harness 16, and a beacon 24. The apparatus of the invention is adapted so that the harness 16 is inflated and the beacon 24 illuminated automatically in response to water contact. A beacon that has been found to be satisfactory is model number L87 light weight beacon manufactured by ACR.
Referring now to FIGS. 1 and 2, the launcher 12 includes a cylindrical missile compartment 26 for housing the self-propelled missile 14, a body-engaging portion 28 attached longitudinally along the underside 29 of the missile compartment and 26 shaped to provide a sleeve for receiving an arm 30 of the rescuer 20. Another compartment 32 oriented longitudinally along an underside 33 of the body-engaging portion 28 contains the flexible line 18 in a coiled or spiral-wound configuration. For reasons of durability and light weight, as well as ease of manufacture, the launcher 12, including the portions forming the missile compartment, the 26 body-engaging portion 28, and the flexible line compartment 32, is made of canvas-like material.
The line 18 preferably is made from nylon or a similar material that is substantially unaffected by sea water, as well as strong enough to pull the weight of a large person. Further, compartment 32 includes a distal flap 33 releasably connected to the flexible line 18 via a half-ring pin and light line assembly 35, through which the flexible line 18 may exit without substantial resistance. Contained within the missile compartment 26 is a cylindrical tube 34, made of aluminum or another high strength lightweight material which is configured to protect and guide the self-propelled missile 14.
The launcher 12 also embodies a generally tube-shaped life-support container 36 having an enclosed end 38 with a hemispherical configuration and an open end 40 with a reduced diameter. The container 36 has a slit 42 running longitudinally in a curved pattern from the open end 40 toward the distal end 38. The open end 40 of the container 36 is configured to be inserted and held within a distal opening 44 in the cylindrical aluminum insert 34, so that the end of the container 36 points away from the rescuer 20. As shown in FIG. 2, the container 36 is configured to receive a collapsed inflatable harness 16.
Attached to the rescuer's end of the cylindrical tube 34 is a trigger mechanism 48 for launching the self-propelled missile 14. The trigger mechanism 48 includes a quick release valve assembly 50, which comprises a cylindrical housing with a valve split ring 51 having ball bearings 52 positioned in captured relation about its circumference. The assembly is biased toward the missile 14 and receives a nipple 54 on the proximal end 56 of a cartridge portion of the missile 14. An L-shaped trigger arm assembly 58 is attached at about a midpoint of one of its legs to a member 60 extending proximally from a plate 62 which engages a circumference of the quick-release valve assembly 50. One end of the trigger arm assembly 58 is pivotally attached to a nozzle assembly 64 and another end is configured to receive the pin portion of a safety ring and end pin 66 as well as a trigger strap 68.
The nozzle assembly 64 further includes a pressure gauge 70 for monitoring and displaying pressure of the air contained within the missile 14 and a machined lip 72. Further, the nozzle assembly 64 has a hollow interior (shown) and an opening (not shown) in communication with the hollow interior and through which air may be caused to flow to the missile nozzle nipple 54 to fill the missile 14.
Attached to the collapsed inflatable harness 16 are a pair of lines 74 which secure the collapsed inflatable harness 16 to the missile 14. A third line 76 attaches the flexible line 16 to the missile 14.
When so configured, the launcher 12 is ready for use. Referring to FIG. 2, the trigger mechanism 48 operates to retain the self-propelled missile 14 in place within the cylindrical missile tube 34, as well as to keep pressurized air within the missile 14. The safety ring and pin 66 insures that the missile 14 is so retained by locking the trigger mechanism 48, thereby preventing any unexpected or accidental launching of the missile 14. Moreover, in its fully charged state, it is contemplated that the self-propelled missile 14 be pressurized with air in the range of 2500 to 3000 psi. Further, as configured, the launcher 12 is evenly balanced fore and aft, thereby minimizing a heavy nose or tail effect when aiming the apparatus.
The rescue apparatus is adapted to be hand held, as shown in FIGS. 1, 2 and 7, for aiming and launch. To facilitate the process, the sleeve receives the rescuers arm and a hand grip 46 is provided.
In order to deploy the self-propelled missile 14, the rescuer 20 removes the safety ring and pin 66 from engagement with the L-shaped trigger arm assembly 58. Referring now to FIG. 3, the rescuer next pulls on the trigger strap 68 which in turn causes the trigger arm assembly 58, through its connection with plate 62, to pull the distally biased quick-release valve split ring 51 from engagement with the nozzle nipple assembly 54. More specifically, when the trigger strap is pulled, the ball bearings 52 positioned about the circumference of the quick-release assembly 50 are removed from engagement with the outer circumference of the nipple assembly 54. Once this has occurred, the pressurized air within the self-propelled missile is permitted to escape through the nipple assembly, thereby propelling the missile 14 out of the launcher and, thereafter, for an extended period toward the target. The cylindrical tube 34, in turn, acts as an initial launch tube and guides the missile trajectory.
Referring now to FIGS. 5 and 6, once the missile 14 has reached its destination and contacted the water, the inflatable harness 16 automatically inflates, ejecting itself out through slit 42 formed in the life-support container 36. That is, an automatic inflation apparatus 78 which is attached to the side of the inflatable harness 16 causes the harness to inflate. An automatic inflation mechanism that has been found to be particularly satisfactory is model V-80,000 EC-4 manufactured by Holkey-Roberts. The inflation apparatus 78 includes a standard CO 2 cartridge 80 and a spring-loaded cartridge piercing device 82 that is held in a "cocked" position by a water-soluble pellet 84 until it has been dissolved by water (two to three seconds). Once the pellet 84 dissolves, the piercing device 82 pierces the CO 2 cartridge 80, thereby allowing it to inflate the harness 16.
At the same time, the missile 14 and life-support container 36 with a beacon 24 (not shown) flashing inside, floats in the water near the victim 22. The victim would then put on the harness 16 and secure it around their chest and under their arms. To aid in securing the harness 16 to the victim 22 the harness 16 can be configured with straps 86 which can be tightened about the victim. Thereafter, the flexible line 18 can be attached to the front of the harness 16 to facilitate a rescue using the flexible line 18 to pull the victim 22 to safety. Once the victim has been rescued the entire self-propelled rescue apparatus 10 will also be retrieved and be available for repackaging for subsequent use.
Recharging the missile 14 requires a specially designed adapter 88 (FIG. 8). This adapter is slotted and half-open on one side to allow it to be slipped over the machined lip 72 formed in the nozzle assembly 64. With this arrangement, the missile 14 is recharged while its installed in the rescue apparatus 10.
It is contemplated that the rescue apparatus will have uses other than water rescue. For example, the life support item might be as simple as a first aid item that is transferred between ships at sea or a handle for a victim stranded on a mountain cliff.
It will be apparent from the foregoing, while a particular form of the invention has been illustrated and described and certain modifications referenced, various other modifications can be made without departing from the spirit and scope of the invention. Accordingly, it is not intended that the invention be limited, except as by the appended claims.
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Rescue apparatus comprising a self-propelled missile mounted on a hand-held launcher and arranged to carry a flotation device in a collapsed condition from the launcher to a distressed target, the launcher and flotation device being connected by a flexible line, so that when the missile is aimed and launched toward the target, the flotation device is carried to the target and then deployed automatically to provide flotation support and establish a "life-line" from the launcher.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a baking device and a baking method thereof, and more especially to a baking device and a baking method thereof for controlling a reliable browning level.
[0003] 2. Description of the Prior Art
[0004] A traditional baking device (such as a toaster or an oven) depends on heating effect of electric current, for example, the primary component of a baking device is a thermal grid made from an Fe—Ni alloy. The resistance coefficient of the Fe—Ni alloy is very large and the Fe—Ni alloy is thinner than copper wire, so electrons movement in the Fe—Ni alloy wire do not easily and collides with other atoms. The collision accelerates the vibrations of the atoms, raising the temperature, and increasing the resistance coefficient, so that the number of electrons is decreased. Because the number of electrons decreases, the amount of vibrations is also reduced. Furthermore, because the vibrations of the atoms are weaker, the strength of the current is raised. Due to the higher current, the vibrations are accelerated, and the temperature is raised again. By the alternation of the two opposite effects, a steady state is reached within several seconds, that is to say, because the two opposite effects counteract each other, the temperature is not raised further, and the current is steady. The heating effect of electric current is red and hot, and the bread is baked.
[0005] For instance, ordinary baking devices control the browning level of food (such as toast) to be baked by the timer which is set in advance. However, the browning level of the toast is difficult to control because of the different kinds of bread which may be used and because the initial temperature of the interior of the baking device is not taken into account. This results in burning, over browning or insufficient browning of the bread. When the browning level of the bread is insufficient, the bread is usually put back into the baking device. Unfortunately, the taste of rebaked toast is not as appealing to peoples' tastes.
[0006] Following is a comprehensive overview of the baking devices currently available to consumers. Several disadvantages exist, most notably:
1. The browning level is difficult to control, so the browning level desired by a user is difficult to attain; 2. When a desired browning level cannot be reached, it is necessary to put the toast back into the baking device again, so time is wasted; and 3. The browning level of different kinds of bread baked in a baking device for the same period of time may not be the same.
[0010] Hence, the inventors of the present invention believe that these shortcomings above are able to be improved upon and finally suggest the present invention which is of a reasonable design and is an effective improvement based on deep research and thought.
SUMMARY OF THE INVENTION
[0011] A baking device and a method thereof for controlling a reliable browning level of the present invention are disclosed to resolve the problem of the browning level being difficult to control.
[0012] An object of the present invention is to provide a baking device capable of baking any type of food, and the food needs to be baked just one time to meet the tastes of people.
[0013] To achieve the above-mentioned object, a baking device for controlling a reliable browning level of the present invention is disclosed. The baking device includes a power converter converting an input AC power supply into a DC power supply, a thermal unit electrically connected to the power converter to heat up a baked food, a temperature sensor electrically connected to the thermal unit to detect the temperature of the baked food, a environment temperature sensor detecting the interior temperature of the baking device, and a microprocessor electrically connected to the temperature sensor and the environment temperature sensor detects the temperature of the baked food and the interior temperature of the baking device for outputting a control voltage to the power converter.
[0014] After a browning level has been selected, a reduced weight owing to the difference in weight lost as the baked food is heated and dries is calculated by the temperature sensor and the microprocessor to define multiple browning levels to suit the tastes of a user.
[0015] To further understand features and technical contents of the present invention, please refer to the following detailed description and drawings related the present invention. However, the drawings are only to be used as references and explanations, not to limit the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a block diagram of a baking device for controlling a reliable browning level of a first embodiment of the present invention;
[0017] FIG. 2 is a block diagram of the interior of the microprocessor of the first embodiment of the present invention;
[0018] FIG. 3 is a flow chart of a baking method for controlling a reliable browning level of the first embodiment of the present invention;
[0019] FIG. 4 is a block diagram of a baking device for controlling a reliable browning level of a second embodiment of the present invention;
[0020] FIG. 5 is a block diagram of the interior of the microprocessor of the second embodiment of the present invention;
[0021] FIG. 6 is a flow chart of a baking method for controlling a reliable browning level of the second embodiment of the present invention;
[0022] FIG. 7 is a block diagram of a baking device for controlling a reliable browning level of a third embodiment of the present invention;
[0023] FIG. 8 is a block diagram of the inner of the microprocessor of the third embodiment of the present invention;
[0024] FIG. 9 is a flow chart of a baking method for controlling a reliable browning level of the third embodiment of the present invention; and
[0025] FIG. 10 is an impedance-time coordinate of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0026] Referring to FIG. 1 , a block diagram of a baking device for controlling a reliable browning level of a first embodiment of the present invention is shown. The device includes a power converter 12 converting an input AC power supply 10 into a DC power supply, and the AC power supply 10 may be 110Vrms/60 HZ. A thermal unit 14 is electrically connected to the power converter 12 to heat up a baked food to be baked. The thermal unit 14 may be a thermal grid. A temperature sensor 16 is electrically connected to the thermal unit 14 to detect the temperature of the baked food. An environment temperature sensor 18 detects the interior temperature of the baking device. A microprocessor 20 is electrically connected to the temperature sensor 16 and the environment temperature sensor 18 detects the temperature of the baked food and the interior temperature of the baking device, and then outputs a control voltage to the power converter 12 .
[0027] Referring to FIG. 2 , a block diagram of the interior of the microprocessor unit 20 of the first embodiment of the present invention is shown. The microprocessor unit 20 includes a memory 202 storing a stable browning level value and a temperature-time-browning converting table, the stable browning level value is provided via a browning level knob of the baking device. The memory 202 may be an EEPROM or a RAM. A comparing element 204 compares the temperature of the baked food and the interior temperature the baking device to provide a current browning level value. The comparing element 204 may be a comparator. A detector 206 converts the value of integrating food temperature with heating time and the interior temperature of baking device into the current browning level value by the temperature-time-browning level converting table. A regulator 208 receives the detecting signal, and then outputs a control voltage to regulate the output power of the power converter 12 .
[0028] Referring to FIG. 3 , a flow chart of a baking method for controlling a reliable browning level of the first embodiment of the present invention is shown. The process of baking is completed when the baking device reaches a predetermined browning level. The baking device includes a power converter 12 , a thermal unit 14 , a temperature sensor 16 , an environment temperature sensor 18 , and a microprocessor 20 . Referring to FIG. 1 and FIG. 2 , the baking method includes the baking device being set with a browning level knob (not shown) which provides a reliable browning level value, the reliable browning level value and the temperature-time-browning level converting table are stored in the memory 202 of the microprocessor 20 (S 100 ).
[0029] A temperature of a baked food is detected by the temperature sensor 16 and integrating the food temperature with heating time are then converted into a temperature-time-browning detecting signal (S 102 ). The interior temperature of the baking device is detected by the environment temperature sensor 18 and is then converted into an environment detecting signal (S 104 ). The comparing element 204 of the microprocessor 20 compares the temperature-time-browning detecting signal and the environment detecting signal for obtaining a current browning level value (S 106 ). The detector 206 of the microprocessor 20 judges that if the reliable browning level value is equal to that of the cur rent browning value (S 108 ), in S 108 , if the judging result is true, the microprocessor 20 outputs a stop signal to the regulator 208 of the microprocessor 20 for outputting a stop voltage to stop the power converter 12 (S 110 ). Alternatively, if the judging result is false, the microprocessor 20 outputs a detecting signal (S 112 ), and the detecting signal is transmitted to the regulator 208 of the microprocessor 20 to generate a controlling voltage for regulating the output power of the power converter (S 114 ).
SECOND EMBODIMENT
[0030] Referring to FIG. 4 , a block diagram of a baking device for controlling a reliable browning level of a second embodiment of the present invention is shown. The baking device includes a power converter 12 converting an input AC power supply 10 into a DC power supply, and the AC power supply 10 may be 110Vrms/60 HZ. A thermal unit 14 is electrically connected to the power converter 12 to heat the food, and the thermal unit 14 may be a thermal grid. A weight sensor 22 is electrically connected to the thermal unit 14 to detect the weight of the baked food. A microprocessor 20 is electrically connected to the weight sensor 22 to detect the weight of the baked food, and then output a control voltage to the power converter 12 .
[0031] Referring to FIG. 5 , a block diagram of the interior of the microprocessor unit 20 of the second embodiment of the present invention is shown. The microprocessor unit 20 includes a memory 202 storing a stable browning level value and a weight-browning level converting table 2020 , the stable browning level value is provided via a browning level knob of the baking device, the memory 202 may be an EEPROM or a RAM. A detector 206 converts the weight of the baking food into a current browning level value by the weight-browning level converting table 2020 . A comparing element 204 compares the percent of the current browning level and the stable browning level for providing a comparing signal, the comparing element 204 may be a comparator. A regulator 208 receives the detecting signal, and then outputs a control voltage to regulate the output power of the power converter 12 .
[0032] Referring to FIG. 6 , a flow chart of a baking method for controlling a reliable browning level of the second embodiment of the present invention is shown. The process of baking is completed when the baking device is controlled under a reliable browning level, the baking device includes a power converter 12 , a thermal unit 14 , a weight sensor 22 , and a microprocessor 20 . Referring to FIG. 4 and FIG. 5 , the baking method includes a reliable browning level value and a weight-browning level converting table 2020 provided by setting a browning level knob (not shown) on the baking device. The reliable browning level value and the weight-browning level converting table 2020 are stored in the memory 202 of the microprocessor 20 (S 200 ).
[0033] The original weight of the baked food is detected by the weight sensor 22 (S 202 ). The baked food is heated by the thermal unit 14 and a current weight of the baked food is measured instantaneously (S 204 ). The comparing element 204 of the microprocessor 20 compares the original weight and the current weight and then outputs a current browning level percent (S 206 ). The detector 206 of the microprocessor 20 determines whether the reliable browning level percent value is equal to the current browning level percent value or not (S 208 ). If the measured result is true, the microprocessor 20 outputs a stop signal to the regulator 208 of the microprocessor 20 for outputting a stop voltage to stop the power converter 12 (S 210 ). Alternatively, if the measured result is false, the microprocessor 20 outputs a comparing signal (S 212 ). The comparing signal is transmitted to the regulator 208 of the microprocessor 20 to output a controlling voltage for regulating the output power of the power converter (S 214 ).
[0034] For the second embodiment, the weight sensor weighs the original weight of the unbaked food and the weight of the baked food instantaneously. The browning level may be estimated by the percent of reduced weight, more weight percent reduced, more higher the browning level to be, heating is stopped when the weight reaches a predetermined percent.
THIRD EMBODIMENT
[0035] Referring to FIG. 7 , a block diagram of a baking device for controlling a reliable browning level of a third embodiment of the present invention is shown. The baking device includes a power converter 12 converting an input AC power supply 10 into a DC power supply. The AC power supply 10 may be 110Vrms/60 HZ. A thermal unit 14 is electrically connected to the power converter 12 to heat up the baked food. The thermal unit 14 may be a thermal grid. An impedance sensor 24 is electrically connected to the thermal unit 14 to detect the impedance of the baked food. A microprocessor 20 is electrically connected to the impedance sensor 24 to receive the impedance of the baked food, and then outputs a control voltage to the power converter 12 .
[0036] Referring to FIG. 8 , a block diagram of the interior of the microprocessor unit 20 of the third embodiment of the present invention is shown. The microprocessor unit 20 includes a memory 202 storing a stable browning level value and an impedance-browning level converting table 2022 . The stable browning level value is provided via a browning level knob of the baking device. The memory 202 may be an EEPROM or a RAM. A detector 206 converts the impedance of the baked food via the impedance-browning level converting table 2022 into a current browning level. A comparing element 204 compares the current browning level and the stable browning level to provide a comparing signal. The comparing element 204 may be a comparator. A regulator 208 receives the comparing signal and then outputs a controlling voltage for regulating the output power of the power converter 12 .
[0037] Referring to FIG. 9 , a flow chart of a baking method for controlling a reliable browning level of the third embodiment of the present invention is shown. The process of the toasting is completed when the baking food reaches a predetermined browning level. The baking device includes a power converter 12 , a thermal unit 14 , a weight sensor 22 , and a microprocessor 20 . Referring to FIG. 7 and FIG. 8 , the baking method includes a reliable browning level value and an impedance-browning level converting table 2022 via a browning level knob (not shown) on the baking device. The reliable browning level value and an impedance-browning level converting table 2022 are stored in the memory 202 of the microprocessor 20 (S 300 ).
[0038] When baked food is put into the baking device to be baked, an original impedance of the baked food is detected by the impedance sensor 24 (S 302 ). A state-changed impedance of the food is obtained after the baking food is heated by the thermal unit 14 (S 304 ). The state-changed impedance is obtained when the baking food becomes dried, but is not yet singed. The state-changed impedance is lower than the original impedance. A current impedance value is obtained as the thermal unit 14 continues to heat the baking food (S 306 ). The current impedance value is converted into an impedance-browning level by the impedance-browning level converting table 2022 (S 308 ). The detector 206 of the microprocessor 20 judges if the reliable browning level is equal to the current browning level or not (S 310 ). If the judge result is true, the microprocessor 20 outputs a stop signal to the regulator 208 of the microprocessor 20 for outputting a stop voltage to stop the power converter 12 (S 312 ). Alternatively, if the judge result is false, the microprocessor 20 outputs a comparing signal (S 314 ). The comparing signal is transmitted to the regulator 208 of the microprocessor 20 to output a control voltage for regulating the output power of the power converter (S 316 ).
[0039] In the third embodiment, the impedance is measured via two measuring sticks placed in the baking device. Referring to FIG. 10 , an impedance-time coordinates of a baked food of the present invention is shown. If the initial value of the food (point A) is somewhat high, as the food dries due to the heating process, the impedance is lower, thermal after the turning point (point B) is reached the thermal time is calculated. If the browning level (point C) is higher than the turning point (point B), the heating time is controlled by the browning level (point C). In this way, the object of the present invention, to control the heating time between point B and point C is achieved. Furthermore, the impedance may cooperate with a capacitance to bring surge, the impedance may be measured by surge frequency. Alternatively, the impedance may be obtained via Ohm's Law.
[0040] The browning level is determined by the moisture content of the baked food; the lower the moisture content, the higher the browning level. Baking device currently available to consumers use time as the only control parameter for determining the browning level, controlling the browning level via the intensity of the heated wire. However, the thickness of the baked food and the initial temperature are contribute to the end result, so the effect can often be somewhat bad. The methods provided in the three embodiments of the present invention can however, control the baking device to a reliable browning level via measuring the relationship of the moisture content of the baked food and the browning level.
[0041] What is disclosed above are only the preferred embodiments of the present invention, and it is therefore intended that the present invention not be limited to the particular embodiment disclosed. It should be understood by those skilled in the art that various equivalent changes may be made depending on the specification and the drawings of present invention without departing from the scope of the present invention.
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The present invention discloses a baking device and method thereof for controlling a reliable browning level and a baking method which controls the parameters of a browning level of a baking device in order to reach the browning level desired by a user. The baking device of the present invention includes a temperature sensor, a weight sensor or an impedance sensor to judge the current browning level of a baked food by the difference in temperature, the weight or the impedance of the baked food. It then compares the results with the reliable browning level stored in the microprocessor of the baking device. The comparing result of the current browning level and the reliable browning are used as a basis of whether to continue to heat the thermal grid or not.
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BRIEF DESCRIPTION OF THE INVENTION
The present invention relates generally to digital video signal processing. More particularly, this invention relates to a technique for scalable buffering in a digital video decoder.
BACKGROUND OF THE INVENTION
Digital image video devices (e.g., high definition television, digital video recorders, cameras, and conference systems) have data rate or bandwidth limitations. A digital image video recording creates an enormous amount of digital data. To accommodate digital image video device bandwidth limitations, and deliver digital data at increased transmission speeds, digital image data is compressed, or encoded, before being transmitted or stored. A compressed digital video image is decompressed, or decoded, prior to its display. Examples of widely used compression techniques (“standards-based”) are those that comply with the Moving Pictures Experts Group (“MPEG”) and Joint Pictures Experts Group (“JPEG”) standards.
Decoding encoded image data is computationally intensive and is associated with a heavily pipelined data-path where vast amounts of data move through a processor. The decoding process may be performed with a dedicated hardware decoder or it may be performed on a general purpose computer. The present invention is applicable to both types of decoders. However, by way of example, the present invention is disclosed in the context of a decoder implemented on a general purpose computer.
A number of advanced processor instruction sets (e.g., Sun SPARC VIS, sold by Sun Microsystems, Inc., Palo Alto, Calif.) have been introduced for use in general purpose computers. These advanced processor instruction sets optimize the computational aspects of standards-based video decoding. However, there is still a need for a standards-based video decoder design that optimizes the heavily pipelined data-path aspects of the video decoder's underlying memory system. CPU performance is directly related to the time the CPU spends in executing a program and the time that the CPU waits for the memory system. By reducing memory system access times, CPU performance can be enhanced.
An optimized decoder design involves several challenges. The design must consider effects that its implementation can have on performance aspects of the decoder's underlying memory system. For example, to facilitate rapid access to data and instructions, a general purpose CPU typically uses a Data Cache (“D-cache”) and a separate Instruction Cache (“I-cache”). Cache use is optimized when required data and instructions are located in a respective cache. CPU stall-cycles come primarily from cache misses (a cache miss occurs when the necessary data or instructions are not in a cache). To optimize cache use and increase overall processor performance, a video decoder should design its data-path both in a way that cache misses are minimized and caches are not underutilized.
Most existing cache use optimization schemes are optimized for a particular platform. Thus, a single cache use optimization scheme is not readily ported to different computer architectures.
Designers often need to make difficult cache use design tradeoffs to design a video decoder that is portable across several architectures. These tradeoffs involve balancing cache use factors that cannot all be maximized at the same time. The results of implementing these design tradeoffs are unpredictable and often lead to costly software rewrites to accommodate some new knowledge about the costs and benefits of the design tradeoffs.
In view of the foregoing, it would be highly desirable to provide an improved video decoder with scalable buffers that can be dynamically re-sized to optimally process a video input stream.
SUMMARY OF THE INVENTION
A method of assigning a buffer size in a video decoder includes the step of establishing a first buffer size for a scalable buffer. A video data stream is then processed with the scalable buffer configured to the first buffer size. A second buffer size is then selected for the scalable buffer. The video stream is then processed with the scalable buffer configured to the second buffer size. Memory utilization data characterizing memory performance during processing with the scalable buffer at the first buffer size and the second buffer size is then created. Afterwards, a buffer size is assigned for the scalable buffer based upon the memory utilization data.
The apparatus of the invention is a computer readable memory to direct a computer to function in a specified manner. The apparatus includes a buffer management module to establish a first buffer size and a second buffer size for a scalable buffer. A video decoding module processes a video stream utilizing the first buffer size and the second buffer size. An analysis module creates memory utilization data characterizing memory performance during processing with the first buffer size and the second buffer size. The video decoding module is then used to assign a buffer size for the scalable buffer in accordance with the memory utilization data.
The techniques of the invention are applicable to decoders formed in hardware or software. That is, the techniques of the invention can be used in connection with micro-coded hardware decoders or software running on a general purpose computer. In either context, the performance of the decoder is analyzed for different buffer sizes. The buffer size that produces the optimal results is subsequently utilized to process the data stream. The assigned buffer size may be used statically or may be changed dynamically. In a dynamic implementation of the invention, if the rate of flow of data and/or instructions in the data stream shifts, the buffer size is altered to accommodate the new data stream.
BRIEF DESCRIPTION OF THE DRAWINGS
For a better understanding of the invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a block diagram of a programmed digital image video decoder with scalable buffering according to an embodiment of the present invention.
FIG. 2 is a block diagram of a video decoder implementation that may be utilized in accordance with an embodiment of the invention.
FIG. 3 is an illustration of a frame of encoded digital image data divided into a set of macroblocks.
FIG. 4A is a graph illustrating instruction cache miss rates corresponding to different data store buffer sizes.
FIG. 4B is a graph illustrating data cache miss rates corresponding to different data store buffer sizes.
FIG. 4C is a graph illustrating overall cache miss rates corresponding to different data store buffer sizes.
FIG. 5 is a flow diagram illustrating a process for determining a buffer size for optimal memory performance in accordance with an embodiment of the invention.
Like reference numerals refer to corresponding parts throughout the drawings.
DETAILED DESCRIPTION OF THE INVENTION
By way of example, the invention is described in connection with a software embodiment of a digital video decoder. Those skilled in the art will appreciate that the concepts of the invention are equally applicable to a hardware embodiment of a digital video decoder.
FIG. 1 illustrates a software-based digital video decoder 100 implemented in a general purpose computer. In an embodiment of the invention, the video decoder 100 includes one or more data processing units (“CPUs”) 110 . Each CPU 110 is connected to a memory 120 , which will typically include both high speed random access memory as well as non-volatile memory (e.g., a magnetic disk drive). The system 100 also includes input and output devices 125 (e.g., a keyboard, mouse, computer monitor, printer, and the like). A communication bus 115 interconnects the CPU 110 , memory 120 , and input/output devices 125 .
The CPU 110 also contains memory in the form of one or more caches 112 . The caches 112 may include a data cache 113 for storing data and an instruction cache 114 for storing instructions.
The memory 120 stores encoded image data 130 to be decoded and a video decoding module 135 for decoding the encoded image data 130 using a standards-based video decoding pipeline. The video decoding module 135 contains a buffer management module 140 for providing scalable buffering capabilities, and an analysis module 145 for analyzing data cache 113 and instruction cache 114 performance (cache miss rates) during a decoding process. The buffer management module 140 allows the video decoder 100 to scale the code size, data size and internal source and destination buffers, such that underlying data cache and instruction cache capabilities can be optimized, as discussed below.
The analysis module 145 accumulates a set of cache performance results (cache miss rates) in relation to programmed data buffer sizes. The analysis module 145 contains a report generator module 150 for reporting at least a subset of the cache performance results. The analysis module 145 also includes a buffer size adjuster 152 . The buffer size adjuster 152 automatically adjusts the size of data store buffers 160 based upon the cache performance results. The buffer size adjuster 152 may be used to set a static buffer size or to accomplish dynamic buffer size adjustments, as discussed below.
FIG. 1 also illustrates data store buffers 160 . The data store buffers 160 are video data buffers implemented as either software array structures or regions of dedicated Static Random Access Memory (SRAM) that store video data between processing stages. The term buffer is sometimes used in connection with caches and other physical memories. As used herein, the term buffer refers to a data structure or physical memory to store video data between processing stages of a video decoder. Thus, in a software video decoder, the buffer may be a software array structure or a region of dedicated SRAM. In a hardware video decoder, the buffer will be a physical memory region between processing stages.
The data store buffers 160 are scalable buffers utilized by the video decoding module 135 . As discussed below, the size of the data store buffers 160 is adjusted and cache performance is analyzed for different data store buffer sizes. Based upon this analysis, an optimal buffer size is subsequently selected and utilized, as discussed below.
While FIG. 1 illustrates a software based module, video decoding module, the disclosed processing techniques are equally applicable to a dedicated hardware architecture. A dedicated hardware decoder may be implemented with a micro-coded engine with its own memory hierarchy, as well as intermediate buffers between stages. In such an embodiment, the hardware decoder includes a hardwired buffer management module 140 , analysis module 145 , and data store buffers 160 . In the case of hardware decoder, the performance of the overall decoder is analyzed for different buffer sizes. The overall decoder performance is largely based upon memory performance within the decoder. Based upon this performance information, buffer resources are assigned, as discussed below.
FIG. 2 illustrates a video decoding module 135 , which may be implemented in software or hardware. An encoded image data bitstream is received at an input node 210 and is presented to a Variable Length Decoder/Inverse Quantization Unit (“VLD/IQ”) 230 for decoding of motion vectors and Discrete Cosine Transform (“DCT”) coefficients, resulting in fixed-length data. The fixed-length data is presented to an Inverse Discrete Cosine Transform Unit (“IDCT”) 240 , which determines Displaced Frame Difference (“DFD”) information (a decoded prediction error signal). The fixed-length data is also applied to a Motion Compensator (“MC”) 250 . The Motion Compensator 250 uses a reference frame signal on line 220 and a motion vector decoded by the VLD/IQ 230 to generate a motion compensated prediction signal. The motion compensated prediction signal is combined with the displaced frame difference information from the IDCT 240 at mixer 260 to produce the final product, a decoded video signal on line 270 .
The operation of the VLD/IQ 230 , IDCT 240 , MC 250 , and mixer 260 are well known in the art. The invention is not directed to the independent operation of these components. Rather, the invention is directed toward the utilization of scalable buffers within a video decoder to optimize the performance of the physical memories (e.g., caches) of the video decoder. This facilitates improved decoder performance. For example, in the case of a decoder operating on a general purpose computer, the performance of the data cache and instruction cache of the CPU are enhanced.
FIG. 2 illustrates buffers 272 , 274 , 276 , and 278 positioned between processing stages of the decoder 135 . Each data store buffer isolates a functional unit's source and/or destination data bit stream from another functional unit in the decoding pipeline. For example, buffer 272 isolates the output of VLD/IQ 230 and the input to IDCT 240 . As long as a source buffer never overflows, and a destination buffer never underflows, each functional unit (e.g., 230 , 240 , and 250 ) can be implemented efficiently.
FIG. 3 illustrates a compressed digital video image frame 300 divided into a set of macroblocks 310 A– 310 N. Each macroblock 310 in the digital image frame 300 contains a 16×16 matrix of encoded image data pixels. A macroblock is a standard processing segment in standards-based video decoders. Most prior art video decoders process a single macroblock at a time. In the case of a decoder operating on a general purpose computer, decoding only one macroblock of image data at a time causes the instruction cache 113 of the CPU 110 to be over-utilized, while the data cache 113 of the CPU 110 is under-utilized. The data cache 113 is under-utilized because it is storing only one macroblock of a data. The instruction cache is over-utilized because it must invoke all instructions for processing of the macroblock through all of the functional units (e.g., 230 , 240 , 250 , and 260 ) of the decoder. In this case, overall video decoder performance could have been improved by making better use of the data cache.
FIG. 4 a illustrates the relationship between instruction cache miss rates and data store buffer sizes. The instruction cache miss rate is highest when a corresponding data store buffer size is small. The instruction cache miss rate decreases as data store buffers increase in size.
FIG. 4 b illustrates the relationship between data cache miss rates and data store buffer sizes. In contrast to the relationship shown in FIG. 4 a , data cache miss rates are lowest when the corresponding data store buffer sizes are small. Data cache miss rates increase as data store buffers increase in size.
FIG. 4 c illustrates the relationship between overall cache-miss rates (data cache and instruction cache miss rates combined) and data store buffer sizes. A data store buffer size closest to the bottom 430 of the curve is optimal. The software decoder implementation of the invention selects a buffer size in accordance with a low overall cache miss-rate. Reliance upon this technique leads to performance improvements of several orders of magnitude for varying decoder architectures.
Designing a software video decoder application with scalable buffers involves several challenges. A software application, once built, typically has a fixed instruction code and data size, forming a “footprint.” The application's code and data structures cannot be changed unless the application is rewritten and recompiled. To take full advantage of the optimal data store buffer size optimizations disclosed above, an optimized decoder application would not only allow for dynamically scalable data store buffer resolutions (without needing to rewrite and recompile the application), it would be written to take full advantage of the scalability of the data store buffers by providing for dynamic scalability across its instruction set and data size. The invention achieves these goals through utilization of performance feedback to dynamically scale buffer size, as discussed below.
Designing a video decoder application with dynamic scalability across its instruction set and data size is necessary to take full advantage of dynamically scalable data store buffers. For instance, as a data store buffer changes in size, the amounts of data being put into and taken out of the buffer by one or more decoding procedures should be adjusted accordingly. The data store buffer I/O should be balanced so as not to underflow the buffer and not to overflow the buffer. The concept of “loop unrolling” can be used to demonstrate how buffer size influences the way data is processed.
Loop unrolling mixes operations from different loop iterations in each iteration of a software loop. In other words, a code loop's “stride” (or “step”) is increased and instructions in the body of the loop are replicated. Table 1 illustrates the concept of loop unrolling.
TABLE 1
An Example of Loop Unrolling
Original Loop
Unrolled Loop
do i = 1,99,1
do i = 1,99,3
a(i) = a(i) + b(i)
a(i) = a(i) + b(i)
enddo
a(i + 1) = a(i + 1) + b(i + 1)
a(i + 2) = a(i + 2) + b(i + 2)
enddo
Table 1 shows a program with two “loops” where each “do loop statement” is written “do [variable]=[start],[stop], [stride].” Although the end result of each “loop” is the same, the body of the unrolled loop is executed only one-third as many times as the original loop. The selection of a data buffer size influences the amount of loop unrolling that is performed. Therefore, the selection of a data buffer size influences the footprint of the corresponding code and thus the instruction memory.
The process of changing the video decoder application's data size and code size can have competing effects on the data cache and the instruction cache. Since loop unrolling increases the code size, more data must be stored in the data cache for the unrolled code to process. At some point, the benefits of unrolling decrease, and the burden of maintaining a large amount of data in the data cache across the unrolled portion of code may cause the data cache to overflow.
To balance the competing effects of loop unrolling, the present invention contemplates a video decoder design where (a) the amount of unrolling done across separable portions of the software decoding pipeline is dynamically scalable by a factor of “N”; (b) the dynamically scalable data store buffers are also scaled by a factor of “N”; and (c) “N” is a multiple number of macroblocks. For example, in a dynamic software implementation, a particular loop is implemented with N different unrolling factors. A single version of the loop is selected based upon the performance of the different unrolled procedures.
Table 2 illustrates an example of a method of determining optimal buffer sizes for use in a decoder. The code is executed at least twice, but typically more than two times with different values of N to create performance data. Based upon the performance data, an optimal buffer size is selected. The code is disclosed as psuedo-code. The pseudo-code used in Table 2 is a computer language that uses universal computer language conventions. While the pseudo-code employed here has been invented solely for the purposes of this description, it is designed to be easily understandable by any computer programmer skilled in the art.
TABLE 2
An Example of a Video Decoding Module
// Cache Management Procedure
read bitstream data
// encoded image data
let N = 4
// programmable number of macroblocks
set each Data Store Buffer Size = 2*N
// data store buffer size is some
// function of“N”
let MAX — MB = 16
// maximum number of macroblocks in
// encoded image data
let MB = 0
// macroblock initialization
do while (MB < MAX – MB){
let i = MB
for N number of macroblocks{
VLD – IQ(i)
// Variable Length Decoder (“VLD”)
// decodes N
i = i + 1
// macroblocks worth of bitstream data
}
let i = MB
for N number of macroblocks{
IDCT(i)
// Inverse Discrete Cosine Transform
// (“IDCT”)
i = i + 1
// transforms N macroblocks of
// coefficients into
}
// DFD information
let i = MB
for N number of macroblocks{
MC(i)
// Motion Compensation (“MC”) Unit
I = i + 1
// reconstructs N macroblocks of DFD
}
// information
let MB = MB + N
}
// Analysis Procedure
Create a set of Performance Results based on
Cache Miss rates in relation to the selected Data Store Buffer Size
// Report Procedure
Report at least a subset of the Performance Results
The operation of the exemplary implementation of a Video Decoding Module shown in Table 2 is written such that each of the key computational software components of the decoding pipeline work over a varying number of macroblocks. The exemplary implementation is explained in the context of a standards-based software decoding pipeline as shown in FIG. 2 .
The exemplary implementation begins by reading the bitstream data. The bitstream data is encoded digital image data and can be accessed by the video decoding module in a variety of ways, such as reading the data from memory, or receiving the data in real-time from transmission media (e.g., satellite, over-the-air, and CATV). Next, the macroblock resolution, “N,” is set to equal to some number of macroblocks. The value of “N” can be set in a number of ways, e.g., at compile time, read from a data file, or even determined dynamically by applying an objective criterion to the selection process. Recall that prior art systems usually process a single macroblock of information at a time. In accordance with the invention, processing is based upon a multiple of macroblocks.
Next, the data store buffers are scaled an appropriate size as a function of “N.” The VLD 13 IQ process operates until N macroblocks of bitstream data are decoded into its corresponding output data store buffer. Then the IDCT process transforms “N” macroblocks of coefficients into Displaced Frame Difference information. Finally, the MC process reconstructs N macroblocks in an efficient software pipeline across N macroblocks.
The exemplary implementation of the video decoding module shown in Table 2 is not meant to be limiting. This implementation is shown solely for purposes of explanation. Using teachings provided in this disclosure, a person skilled in the art of computer programming could implement the present invention to optimize underlying cache utilization in a number of ways.
The notion of having a video decoder design with a scalable buffer resolution allows for powerful optimizations to be made dynamically. A designer can accumulate results for cache miss rates corresponding to various data store buffer size resolutions and pick the most optimal buffer resolution in its cache behavior. To illustrate this approach, refer to FIG. 5 , which illustrates a process 500 for determining a video decoder buffer size for optimal performance.
To begin the process of determining a buffer size for optimal performance, encoded image data 510 is presented to the video decoding module 135 . As noted above, the encoded image data 510 can be accessed by the video decoding module 135 in a number of ways. Next, a number “N,” representing a data store buffer size is selected 520 . There are a number of ways that the value of “N” can be chosen, e.g., at compile time or by being read from a data file. The number “N” represents a multiple of a basic macroblock encoded image data block. Then, at least a subset of the encoded image data 510 is decoded 530 using a standards-based software decoding pipeline. Data cache and instruction cache miss rates are determined 540 and stored 550 . If the cache miss rates are not optimal 560 for the underlying memory system configuration, then the process starts over again at step 520 . By way of example, the optimal cache miss rate may be set at some predetermined value (e.g., below 1%). Alternately, step 560 may be implemented to measure a predetermined of iterations.
If the condition tested at step 560 is not satisfied, processing returns to step 520 . It the condition tested at step 560 is satisfied, the data store buffers are then set (step 570 ). As previously indicated, the buffer size adjuster module 152 may be used to set the data store buffer size. This data store buffer size may be fixed (static) during subsequent processing. Alternately, the data store buffer size may be dynamically changed by intermittently or continuously processing the encoded image data in accordance with the processing steps of FIG. 5 .
Those skilled in the art will appreciate that the processing steps of FIG. 5 can be modified for a hardware decoder. In such a case, the step of determining cache performance results (step 540 ) would be substituted with the step of determining memory performance results, while the step of determining optimal cache performance behavior (step 560 ) would be substituted with the step of determining optimal memory performance behavior.
Observe that the value “N” can also represent the amount that the code and data should be “unrolled” in the video decoding pipeline. The implementation of the video decoder with scalable buffering, as disclosed above, can alternatively be used by a video decoder architecture designer to determine optimal hardware buffer sizes.
The present invention can be implemented as a computer program product that includes a computer program mechanism embedded in a computer readable storage medium. For instance, the computer program product could contain the program modules shown in FIG. 5 . These program modules may be stored on a CD-ROM, magnetic disk storage product, or any other computer readable data or program storage product. The software modules in the computer program product may also be distributed electronically, via the Internet or otherwise, by transmission of a computer data signal (in which the software modules are embedded) on a carrier wave.
The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the invention. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the invention. In other instances, well known circuits and devices are shown in block diagram form in order to avoid unnecessary distraction from the underlying invention. Thus, the foregoing descriptions of specific embodiments of the present invention are presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, obviously many modifications and variations are possible in view of the above teachings. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalents.
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A method of assigning a buffer size in a video decoder includes the step of establishing a first buffer size for a scalable buffer. A video data stream is then processed with the scalable buffer configured to the first buffer size. A second buffer size is then selected for the scalable buffer. The video stream is then processed with the scalable buffer configured to the second buffer size. Memory utilization data characterizing memory performance during processing with the scalable buffer at the first buffer size and the second buffer size is then created. Afterwards, a buffer size is assigned for the scalable buffer in accordance with the memory utilization data.
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This application is a continuation of International patent application no. PCT/EP2006/003904 filed on Apr. 27, 2006 and claims the benefit of German patent application no. 10 2005 020 569.0 filed Apr. 30, 2005, each of which is incorporated herein and made a part hereof by reference.
BACKGROUND OF THE INVENTION
The invention relates to an implantable device for determining intracranial pressures, wherein a pressure measuring device is used, which is operatively connected to a sensor for a telemetric measured value transfer.
The determination of intracranial pressure assumes an extremely important role in neurosurgical procedures. The most precise and simple minimally invasive measurement of intracranial pressure possible counts to this day as one of the aims of medical technology that has not been satisfactorily resolved.
It has been the object of numerous inventions to solve this problem. However, all the systems available hitherto have serious disadvantages, and to overcome these is the object of the invention presented here.
Invasive measurement methods have prevailed in clinical practice, in which a sensor is inserted into the body, wherein the signal is passed via a cable connection to an external device for display and evaluation of the measured value. This frequently occurs in combination with an artificial drainage pipe, through which brain fluid is to be drained out of the body. The very high risk of infection is critical with such systems. Long procedures can only be conducted by very expensive prophylaxis against infections and with multiple replacements of the pressure sensor. However, especially in the case of patients with hydrocephalus, it is the progress of the intracranial pressure in an out of clinic situation after implantation of an internal artificial drainage system that is of high diagnostic interest. Systems, which pass the measured signal through the intact skin or allow measurement through the skin, are suitable for such tasks.
Patent DE 196 38 813 C1 describes an implantable pressure sensor, which is connected to flexible foil strip conductors and is surrounded by a substrate in the region of the sensor element, which has a higher mechanical strength than the foil strip conductor and which is enveloped together with the sensor element into a flexible body. The structure should make a reliable and inexpensive measuring device possible, which does not, however, enable any reduction with respect to the risk of infection because of the necessary penetration of the skin. In association with the sensor technology, reference is made to patent U.S. Pat. No. 4,738,267, in which a plastic capsule with a membrane is used, to which a strain gauge is attached. The imbalance of the Wheatstone bridge is interpreted as the magnitude for the existing pressure. Such a sensor operates imprecisely and exhibits an unacceptably high drift behaviour. For this reason, it has not prevailed as implantable intracranial pressure sensor.
The same technique is also described for telemetric determination of intracorporeal pressures in patent application DE 197 05 474 as an application for a patent of addition to DE 196 38 813 C1. However, there are no indications given here as to how biocompatibility is to be assured. Such a sensor has so far not advanced to the commercial stage.
A likewise telemetric method for determining intracranial pressure is described in patent U.S. Pat. No. 6,113,553. The claims applied for here relate to measurement that is as drift-free and stable in the long term as possible with description of the electronic structure. A capacitive structure is used here, wherein the sensor is to be embedded in the bone of the patient. This is necessary because of the bulky structure of the sensor. The extent to which the actual properties of the sensor design meet the high requirements for intracranial pressure measurement with respect to accuracy and drift behaviour is not known, since such a sensor is not as yet commercially available and therefore could not be subjected to any independent tests.
A method for determining intracranial pressure without skin penetration is likewise described in patent U.S. Pat. No. 4,676,255 from 1987. The idea here was to use the principle of relaxed membranes. A sensor placed under the skin has its zero position as long as intracranially in relation to the surrounding area no positive or negative differential pressure is present. When the intracranial pressure rises or falls, the sensor moves out of the zero position. The precise pressure that is necessary to bring the sensor into the zero position again is now applied through the skin. The pressure necessary for this should then correspond to the intracranial pressure. This method has not been able to prevail clinically. Reasons for this are the variance of skin from patient to patient, the technically difficult and imperfect determination of the zero position and also the complicated generation of the necessary external pressure pad.
Substantially better possibilities are offered by telemetric approaches, in which an extremely small pressure sensor is inserted into the body, which is connected by means of cable likewise inserted into the body to a coil, by means of which, on the one hand, the sensor can be supplied with energy where required and, on the other hand, the measured signal can be transmitted to the outside to a receiver unit for further processing.
A method is described in patent DE 198 58 172 that determines the intracorporeal pressure directly by means of a sensor element using microsystems technology. This centres on the determination of the internal pressure of the eye. The implant should therefore be as small and light as possible. The coating of the sensor is of decisive importance when using this technology to determine intracranial pressure. Such a sensor is described in patent DE 101 56 494, wherein a metal layer as well as a biocompatible plastic layer is provided at least in sections to assure biocompatibility. Such a structure has considerable disadvantages. A coating of the sensor element of whatever type permits impairment of the measurement because of the penetration through this very layer, the properties of which can change over time. The layer can be damaged as a result of the actions of forces from the outside. A drift behaviour can also be problematic as a result of ageing, in particular of the plastic layers.
In order to ensure a homogeneous and secure transfer of the pressure prevailing around the sensor, a technique is described in patent EP 1 312 302 A2, in which a medium arranged around the sensor is surrounded by a flexible sheath. How the biocompatibility of the flexible sheath is to be assured is not described in the patent document. The favoured use of silicone oil in the application for optimum transfer of the existing pressure appears problematic taking into consideration the risk factors.
SUMMARY OF THE INVENTION
The object forming the basis of the invention is, with an implantable device of the above general type, to use a miniaturised chip to determine the absolute pressure so that the biocompatibility of the implant is also assured in the long term and also that a measurement can be performed that is as far as possible drift-free and highly precise.
This object is achieved according to the invention with an implantable device of the above-described type in that the pressure measuring device is a microchip, that the microchip is located in a rigid housing, and that the pressure transfer from the outside inwards occurs through a very thin biocompatible membrane, the pressure-dependent movement of which acts on the pressure measuring device via a transfer medium.
The pressure sensor, which is arranged on a microchip and integrated into this, is protected from the surrounding area in the best possible way because of the arrangement in a rigid housing that is hermetically closed, and the surrounding area is also protected from the discharge of dangerous substances. By using a very thin membrane, the pressure of the brain fluid can be transferred to the interior of the rigid housing, and in this interior the pressure-dependent movement of the membrane is transmitted to the pressure measuring device via a transfer medium, so that a reliable and very direct determination of pressure fluctuations of the surrounding brain fluid is possible.
In particular, difficulties with respect to the passivation of the electronically operating sensor are overcome, which in particular concern the reliability of the protection with respect to ageing or damage, the impairment of the pressure transfer through the applied protective layer and the incalculable drift resulting in material changes occurring over time after implantation.
In a first preferred embodiment, air or a special gas or a liquid is used as transfer medium, wherein this transfer medium fills a chamber inside the rigid housing.
When using a gas as filling medium of the chamber, the mode of operation of the device can be described simply and precisely using the ideal gas equation. FIG. 1 shows a cylindrical container, the floor and cylindrical side wall of which are designed to be very thick, while its cover is designed to be very thin-walled as a membrane. The following applies for constant temperature conditions
p*V =constant (1)
If the pressure outside the container changes, there results a displacement of the membrane that can be calculated and is determined by the volume VI in the container, the characteristic of the membrane and the value of the externally acting pressure change. FIG. 2 shows a possible displacement of such a membrane for the case of the external pressure rise, wherein because of the stresses occurring in the membrane as a result of the curvature, the pressures inside and outside the container can be different. However, for each membrane position there is a characteristic pressure situation in the container, which corresponds to an externally prevailing pressure. Therefore, conclusions can be drawn with respect to the external pressure by measuring the pressure in the container. The absolute movement of the membrane is not linear to the prevailing pressure difference. If one wishes to perform an indirect pressure measurement by the pressure measurement in a container, then the chamber should have a relaxed membrane for the most frequently occurring pressure, as shown in FIG. 1 . The lower the instance of stresses in the membrane with external pressure fluctuations, the more precise the pressure transfer from the outside inwards and the more precise the measurement becomes. In the best case, the pressure to be measured does not reach any values, at which substantial stresses result in the membrane.
FIG. 3 shows the displacement for the case of the drop in the externally prevailing pressure. Depending on the characteristic and shape of the membrane, no change, or only a very slight change, in stress results within the membrane. The principle of the relaxed membranes applies, wherein, provided that the membrane does not absorb any stresses, the pressure adjusts to the same value on both sides of the membrane. This principle is known in the art and is frequently used. However, it was not hitherto known that this principle can be ideally used for measuring body pressures and also safely for long periods of time and drift-free also for miniaturized microchip sensors, which are produced on the basis of silicon and could convincingly demonstrate their efficiency in many technical applications.
In order to achieve as efficient and direct a pressure transfer as possible from the outside inwards, although the preferably metal membrane (made ideally of sheet titanium or a titanium foil) is comparatively rigid, the air volume available in the sensor should be as low as possible at ambient pressure. FIG. 1 shows a container filled with gas (air), the internal pressure of which corresponds exactly to the external pressure without the membrane being curved. FIG. 3 shows this same container, but now for a lower external pressure: the membrane is turned outwards. As a consequence the pressure in the container also drops. FIG. 4 shows a container, wherein the air volume is designed to be minimally small. However, since in this case the membrane is designed exactly as in FIG. 1 to FIG. 3 , the theoretically displaceable air volume in the sensor, with which still no appreciable stresses result in the membrane, is precisely as large as in the cases with large container volume ( FIG. 1 to FIG. 3 ). The membrane can now transfer the external pressure without any substantial membrane movement to the container chamber because of the very small internal air volume. Only a very small membrane displacement is necessary to create a pressure equilibrium for this container between inside and outside even with substantial changes in the external pressure. Because of the small size of the air chamber in the container according to FIG. 4 , the representation applies for all three case, as shown and described in FIG. 1 to FIG. 3 . The membrane displacement is scarcely visible. In the case of intracranial pressure measurement, pressure fluctuations of few cm water column are of therapeutic interest. The absolute values of these pressure fluctuations always lie in the range of atmospheric pressure fluctuations, i.e. approximately at 10 m water column +/−1 m water column. Sensors, which should be used in high mountains, for example, would therefore have to be designed differently accordingly. The more precisely the normal ambient pressure can be restricted in the individual case, the more precisely the pressure recorder can operate, since the relevant absolute pressure range can be restricted further. Measurements of the intracorporeal absolute pressure are then not possible or defective for pressure values lying outside the range.
To form an ideal pressure sensor for the measurement of intracranial pressure, only a little more air volume is used on the sensor side than is displaced by the membrane displacement in the case of a pressure gradient from the outside inwards to the amount of maximum 100 cm water column, preferably also only 50 cm water column. In this case, the space inside the sensor should be configured such that no obstacles formed by sensor components oppose the membrane movement. A rise in the pressure to be measured to the maximum permissible value leads to a membrane movement, which just does not yet allow any contact of the membrane with the actual sensor unit, and contact results with a further rise in pressure.
In particular for large pressure ranges embodiments are also provided, wherein a stress-free or low-stress displacement of the membrane does not exclusively result. Sensors may be considered here that can be used both with extremely low and extremely high pressure to be measured. In this case, the signal of the pressure recorder does not indicate a uniform progress. The sensor changes its characteristic as a function of the stress state in the membrane, which is dependent in turn on the prevailing pressure. Such sensors have an individual characteristic that enables them to associate an externally prevailing pressure with a measured pressure inside the sensor. The association can be achieved by recognition of the sensor by the external reader, which then knows the pressure value corresponding to the transmitted signal.
The gas used can be a gas from the group of noble gases, for example.
It is advantageous if, with the use of a gas as transfer medium, its gas volume is less than a cubic millimetre, preferably less than 0.1 cubic millimetre.
In a preferred embodiment, the housing interior is filled with a gas-displacing filler material except for the provided volume of gas or liquid.
In this case, this can be a plastic material, a ceramic material or a metal material, for example.
It is advantageous in particular if the filler material leaves a minimum-volume pressure chamber including supply duct free on the pressure-sensitive faces of the microchip, and if the filler material leaves a housing cavity as pressure chamber free below the membrane, and if the two pressure chambers are connected by a small-volume conduit.
In another embodiment, the transfer medium can have at least one mechanical transfer member which is movable by the membrane.
The transfer member can be held either on the microchip or on a support receiving the microchip, in another embodiment on the membrane.
In a first embodiment, the transfer member is a pressure foot. In another case, the transfer member is a spring, in particular a U-shaped leaf spring.
In this case, it is favourable if the spring is held on the housing or the support by means of holding elements.
In a further preferred exemplary embodiment, the transfer member has a clip, which is disposed on the housing or on a support receiving the microchip and which abuts against the microchip or the membrane respectively with a foot.
It is favourable if stop elements are provided, which restrict the movement of the mechanical transfer member.
The transfer medium can also be a highly viscous oil or a vulcanised or polymerised material. In particular, a cross-linked silicone may be considered as transfer medium in this case.
The microchip can be completely encapsulated with the vulcanised or polymerised material.
However, it is advantageous if the microchip is only covered or encapsulated with the vulcanised or polymerised material in the region of a pressure sensor, whereas the other regions are not covered with such a material.
The vulcanised or polymerised material can fill the entire cavity between the microchip and the membrane, but according to a preferred embodiment it can also be provided that the vulcanised or polymerised material only abuts against the membrane in the region of the pressure sensor, so that a pressure transfer occurs only in this region.
The vulcanised or polymerised material can also be arranged on the membrane, so that the membrane is covered with the vulcanised or polymerised material in a region located opposite the pressure sensor of the microchip and this material abuts against the microchip at least in the region of the pressure sensor.
It can also be advantageous here if the vulcanised or polymerised material abuts against the microchip only in the region of the pressure sensor, but the other regions of the microchip remain free.
The rigid housing can be made of any materials that are biocompatible. Particularly advantageous is the configuration made of ceramic, of a biocompatible plastic such as polyether ether ketone or polyether ketone ketone, for example, or the configuration as a metal housing, wherein the metal used is preferably titanium or a titanium alloy.
The membrane is preferably made of metal, in particular titanium or a titanium alloy.
It is advantageous here if the membrane has a thickness of less than 0.05 millimeters, preferably of less than 0.01 millimeters, and further preferred about 0.005 millimeters.
Depending on the embodiment, the membrane can have a flexible surface of between 1 mm 2 and 100 mm 2 , in particular of about 4 mm 2 .
It is favourable if the membrane is welded to the housing.
For example, it can be provided that the membrane is provided with a sheet metal frame and is welded with the frame to the housing.
In a special embodiment with a tubular housing the frame can be formed by a sleeve, which can be slid onto the tubular housing to close this.
This sleeve can be welded simultaneously with the membrane on the tubular housing along the outer edge of the sleeve, wherein a hole in the housing wall is closed precisely so that the membrane, and not the sleeve, comes to lie over the hole and is secured there.
In another preferred embodiment, it is provided that the membrane is configured in one piece with the housing. This results in maximum protection against leakage.
The membrane can have regions of different thickness. In particular it can be provided that the membrane is thicker in its edge regions than in its central region. As a result of this, a high strength is achieved in the transition region between the membrane and housing, which enables leakage in this region to be reliably prevented. In a preferred embodiment it is provided that besides at least one pressure sensor the microchip has at least one further sensor. This can be a temperature sensor, for example.
It is additionally favourable if, besides the pressure sensor and besides possibly further sensors, the microchip comprises an analog-to-digital converter, which converts the analog electrical signals of the sensors into digital signals. This assures that the signals from the sensor are transmitted in digital form to an evaluation unit outside the body, so that the susceptibility to interference is reduced quite considerably compared to the transmission of analog signals. The analog-to-digital converter can be integrated on the microchip as can the sensor and as can possibly other electronic function units, e.g. units for the unambiguous identification of the microchip or units, which prepare the digital signals for the transmission via a high-frequency carrier.
As a result of the integration of these functions in a microchip, it is possible to construct a device of very small design, so that this device can be placed at the desired location without difficulties.
In a particularly preferred embodiment it is provided that the microchip is connected to a power and signal transmission line, which connects to a data processing device outside the body or to a transmission coil. Power can thus be supplied externally to the microchip, no power storage means are necessary in the device, and as a result of this, on the one hand, the service life is increased and, on the other hand, the implantable device can be very small.
Still further electronic components in addition to the microchip can be arranged in the housing in all embodiments, e.g. diodes and capacitors to restrict power and buffer power. It is advantageous in this case if a support is arranged in the housing, to which both the microchip and these electronic components are attached and which also receives the connection leads between the microchip, the additional electronic components and the power and signal transmission line.
It is possible, in principle, to arrange the transmission coil in the rigid housing. However, in most cases it advantageous to arrange the power and signal transmission line outside the rigid housing, so that the rigid housing only encloses the microchip and the electronic units that are absolutely necessary thereon and can be of small design accordingly.
It is advantageous if all electrical and electronic components and other non-biocompatible components are housed in the housing, since these components are hermetically sealed relative to the surrounding area. In certain exemplary embodiments the transmission coil can be arranged outside the housing, if need be, and this can be configured to be biocompatible. For example, the coil can be made of gold, platinum or silver and be encased in an atoxic and biocompatible manner.
The power and signal transmission line is advantageously guided out of the rigid housing through a hermetically sealed bushing. This ensures that the interior of the housing is sealed absolutely tightly with respect to the exterior, and in spite of this power can be supplied to the microchip and the digital signals generated by the microchip can be transmitted to an evaluation unit. Such a hermetic bushing is naturally only necessary for the power transmission when the transmission coil is arranged inside the rigid housing, however if the transmission coil is arranged outside the rigid housing, both the power transmission line and the signal transmission line must be directed through such a bushing. These can be separate lines or can also be a common line.
It is favourable if a releasable coupling, in particular in the form of a plug contact, is arranged in the power and signal transmission line. In this case, it is generally provided that this plug contact is also hermetically sealed with respect to the surrounding area.
In other cases, the hermetic bushing in the housing is permanently connected to the power and signal transmission line, e.g. by soldering, welding, by conductive adhesive or crimping.
It is additionally advantageous if the rigid housing is partially provided with a plastic casing or a plastic covering, which, however, leaves at least the surface of the membrane free. Such a plastic casing or plastic covering additionally protects the housing, and the surrounding tissue is additionally protected as a result of this.
The intracranial pressure measurement can be conducted at different measurement sites in the brain, and different configurations result for the rigid housing in keeping with the different measurement sites.
In a first preferred embodiment it is provided that the rigid housing is tubular in configuration.
In the case of such a tubular housing a window, which is closed by the membrane, can be provided in the housing wall.
It is particularly favourable if the diameter of the housing lies to between 2 mm and 3.5 mm, in particular between 2.5 mm and 3 mm. Such a housing is particularly suitable for intraventricular pressure measurement, the outside diameter corresponds to a typical ventricle catheter normally used in hydrocephalus therapy.
In this case, the length of the housing can lie to between 10 mm and 30 mm, in particular about 20 mm. This is thus a very small housing, which can also be arranged in deeper regions of the brain without difficulty and then connects to the transmission coil or to the evaluation unit by means of the power and signal transmission line.
In this case, it is advantageous if the pressure sensor is arranged approximately in the centre of the longitudinal extent of the housing.
It is provided in another embodiment that the length of the tubular housing lies to between 80 mm and 120 mm, in particular about 100 mm. With such a configuration, the tubular housing extends from the measurement site as far as the outside of the cranium, so that a power and signal transmission line directed hermetically through the housing wall is not absolutely necessary.
With such a configuration it is advantageous if the microchip and the membrane are arranged at one end of the tubular housing and a transmission coil at the opposite end. This then preferably lies outside the cranial bone.
In another preferred configuration, the rigid housing can have a closed fluid chamber, which adjoins the membrane on the outside and is connected to a supply conduit for fluid. In the case of such a configuration, the pressure of the fluid in the closed fluid chamber is determined by the pressure sensor via the membrane. This can be brain fluid directly or can be measurement fluid, which is located in the closed fluid chamber and which is acted on by the pressure of the brain fluid in a different manner.
The fluid chamber can additionally have a drainage pipe for fluid. This is important in particular if brain fluid is directed through the fluid chamber and then removed from the brain chamber via the drainage pipe.
It is favourable with such a configuration if the rigid housing has the shape of a shallow can with an upper measurement chamber receiving the microchip and the transfer medium and a lower region forming the fluid chamber. Such a housing in the shape of a shallow can can be placed externally on the cranial bone, i.e. either over the drill hole in the cranial bone or directly next to this.
It is advantageous if the membrane divides the interior of the housing into the measurement chamber and the fluid chamber, as a result of which the membrane extends over a very large area and reacts appropriately sensitively to pressure changes of the fluid in the fluid chamber.
The supply conduit for the fluid can run substantially perpendicularly in relation to a lower boundary wall of the fluid chamber. This is advantageous particularly when the housing is placed directly on a drill hole in the cranial bone, the supply conduit then being able to pass through this drill hole.
For example, the supply conduit for the fluid enters the fluid chamber substantially centrally in relation to a lower boundary wall of the fluid chamber.
In another embodiment it is provided that the supply conduit for the fluid runs substantially parallel in relation to a lower boundary wall of the fluid chamber.
The drainage pipe for the brain fluid can also run parallel to the lower boundary wall. With such a configuration the housing can also be arranged next to the drill hole in the top of the cranium, the supply conduit then being guided through the drill hole and directed parallel to the cranial bone into the fluid chamber.
It is favourable if a non-return valve is arranged in the drainage pipe.
The drainage pipe can open into a reservoir, from which liquid can be backwashed, for example, in order clean the fluid conduits.
It is favourable if the supply conduit is connected to an extension tube, which is open at its end remote from the fluid chamber. Such an extension tube acts as a ventricle catheter and can direct brain fluid from the measurement region directly into the fluid chamber. With such an arrangement the intracranial pressure can be determined at the entry region of the extension tube.
In another embodiment it is provided that the supply conduit is connected to an extension tube, which is closed at its end remote from the fluid chamber by means of a flexible membrane. The extension tube and the fluid chamber are filled with a liquid or a gas and form a closed space, which acts as a pressure transfer medium between the membrane closing off the extension tube and the membrane closing off the measurement chamber.
The wall thickness of the rigid housing can lie between 0.3 mm and 2 mm, so that a deformation-resistant rigid housing is obtained.
To further increase this deformation resistance, it can be provided that the walls of the rigid housing are protected against deformation by reinforcement structures.
In a further preferred embodiment, the measurement chamber can be arranged in an insert, which can be inserted into the housing and closes this in the manner of a cover, wherein the insert carries a membrane, which separates the measurement chamber from the interior of the housing forming the fluid chamber. Therefore, the insert with the membrane and the separated measurement chamber form a separate structural part, which can be inserted into the housing and which as a result of the insertion closes off the housing and also separates the fluid chamber.
The membrane can be a metal foil, which is soldered or welded to the structural part receiving the measurement chamber. This is also possible when the membrane is not held on a separate insert, but on a part of the rigid housing itself.
A permanent and secure seal of the measurement chamber is obtained as a result of the soldering and welding.
According to a preferred embodiment it can be provided that the structural part receiving the measurement chamber has a planar rim, against which the membrane lies flat, that an annular abutment element is arranged opposite the planar rim on the side opposite the structural part, and that the membrane is soldered or welded both to the structural part and to the abutment element. The abutment element and the structural part thus receive the membrane between them in a sandwich-like arrangement and enable the membrane to be soldered or welded both to the structural part and to the abutment element, so that the connection point is also mechanically secured to the outside.
The structural part can be made of metal, preferably titanium or a titanium alloy.
The abutment element can likewise be made of metal, in particular titanium or a titanium alloy.
The membrane can also be made of metal, in particular titanium or a titanium alloy.
It is favourable in this case if the thickness of the membrane lies between 1/100 mm and 5/100 mm, preferably in the order of 2 to 3/100 mm. The abutment element can preferably have a height of between 3/10 and 8/10 mm, in particular in the order of 5/10 mm.
The combination of features described above is particularly advantageous, but the invention also relates to configurations, in which these features are utilised only individually or in which only a portion of these features is utilised in combination.
The invention additionally relates to a process for the production of a rigid housing with a membrane for use in an implantable device of the type described above. Such a process is characterised according to the invention in that a specific wall region of the otherwise rigid housing is weakened by a chemical etching process or electrolytic removal process to such an extent that it forms a flexible membrane.
Overall it can be provided that the thickness of the specific wall region is reduced by machining before the etching or removal process.
The thickness of the membrane can be selected to be equal over the entire membrane surface, but according to a preferred embodiment it is provided that the thickness of the specific wall region is selected to vary in thickness before the etching or removal process, so that after the etching or removal process a membrane is obtained that has different thicknesses in different regions.
In particular it can be provided that the thickness of the specific wall region is reduced to a lesser degree in the outer wall regions than in the central region.
A process for the production of a rigid housing with a membrane for an implantable device of the described type can also be characterised according to the invention in that a membrane is laid flat against a planar rim of a structural part receiving a measurement chamber, that on the side opposite the structural part an annular abutment element located opposite the rim is laid flat against the membrane, said membrane is clamped between the structural part and the abutment element, and then the structural part, the membrane and the annular abutment element are soldered or welded together.
In this case, it is advantageous if the membrane is allowed to project slightly beyond the contour of the structural part and/or the annular abutment element and the soldering or welding is conducted completely or partially on this projecting edge strip.
It is also possible here, particularly in the case of welding, to remove the piece of membrane projecting beyond the contour of the structural part and/or the annular abutment element during the welding process.
BRIEF DESCRIPTION OF THE DRAWINGS
The following description of preferred embodiments of the invention serves as more detailed explanation in association with the drawing:
FIG. 1 is a schematic view of a rigid housing to receive a microchip provided with a pressure sensor and a thin flexible membrane closing off the housing on one side, in a neutral position;
FIG. 2 is a view similar to FIG. 1 with the membrane in a pressed-in position;
FIG. 3 is a view similar to FIG. 1 with the membrane in a pushed-out position;
FIG. 4 is a view similar to FIG. 1 with a very small-volume interior surrounded by the housing;
FIG. 5 is a schematic view of a rigid housing closed with a membrane with a microchip arranged therein with different function regions;
FIG. 5 a is a view similar to FIG. 5 with a support receiving the microchip and additional electronic components;
FIG. 6 is a schematic view in longitudinal section of a tubular housing with a membrane and a microchip arranged in the housing;
FIG. 7 is an enlarged detail view of the housing of FIG. 6 in the region of the membrane;
FIG. 8 shows a sleeve-like frame for sliding onto the tubular housing of FIG. 6 ;
FIG. 9 is a perspective view of the lower end of the housing of FIG. 6 with sleeve-like frame slid thereon;
FIG. 10 is a schematic view in longitudinal section of the tube-shaped housing of FIG. 6 with transmission coil disposed therein;
FIG. 11 is a schematic representation of a rigid housing placed inside the brain with the microchip arranged therein and a transmission coil arranged on the cranial bone;
FIG. 12 is a schematic detail view of the implantable device of FIG. 11 ;
FIG. 13 is a schematic view of a connection means of a power and signal line between the rigid housing and the transmission coil in the implantable device of FIG. 11 ;
FIG. 14 is a perspective view in partial section of a preferred exemplary embodiment of a rigid housing with the microchip received therein;
FIG. 15 is a sectional view through a transmission coil;
FIG. 16 shows a manipulation tool for implantation of the rigid housing into the brain before insertion of the rigid housing into the interior of the brain;
FIG. 17 is a representation similar to Figure 16 during advancing of the rigid housing into the brain;
FIG. 18 is a representation similar to FIG. 16 after placement of the rigid housing in the brain and during withdrawal of the manipulation tool;
FIG. 19 is a view similar to FIG. 16 with the rigid housing in place and after the manipulation tool has been withdrawn;
FIG. 20 is a view similar to FIG. 11 with a rigid housing arranged outside the cranial bone and a connection tube extending into the interior of the brain;
FIG. 21 is a schematic sectional view through a rigid housing with a measurement chamber and a fluid chamber;
FIG. 22 is a sectional view of a preferred exemplary embodiment of a rigid housing with a measurement chamber receiving a microchip and a fluid conduit passing through the fluid chamber;
FIG. 23 is a view similar to FIG. 22 with a supply conduit opening vertically into the floor of the housing;
FIG. 24 is a schematic representation of a rigid housing covering a drill hole in the top of the cranium with a catheter-type supply conduit;
FIG. 25 is a view similar to FIG. 23 with a protective cap covering the rigid housing;
FIG. 26 is a view of a rigid housing similar to FIG. 23 , but without a drainage pipe;
FIG. 27 is a schematic side view of the rigid housing of FIG. 23 with a non-return valve in the drainage pipe and a liquid reservoir connected to the drainage pipe;
FIG. 28 is a schematic representation of a rigid housing arranged next to a drill hole in the top of the cranium and a supply conduit passing through the drill hole into the brain;
FIG. 29 is a schematic side view similar to FIG. 21 with a catheter-type extension closed off by the membrane;
FIG. 30 is a schematic sectional view of a rigid housing similar to FIG. 23 , but without a transmission coil in the interior of the rigid housing;
FIG. 31 is a schematic representation of a rigid housing covering a drill hole in the top of the cranium with a transmission coil laid on the top of the cranium next to the rigid housing;
FIG. 32 is a view similar to FIG. 31 with a transmission coil surrounding the rigid housing;
FIG. 33 a is a schematic cross-sectional representation of a housing with a predetermined wall region of reduced thickness before an etching process for the production of a membrane;
FIG. 33 b is a view similar to FIG. 33 a after an etching process;
FIG. 34 a is a view similar to FIG. 33 a in the case of another cross-sectional form of the predetermined wall region;
FIG. 34 b is a view similar to FIG. 34 a after the etching process;
FIG. 35 a is a schematic representation of a sub-region of the microchip with a silicone coating before the final positioning of the microchip and membrane;
FIG. 35 b is a view similar to FIG. 35 a after the final positioning of the microchip and membrane with the silicone coating abutting against the membrane in sections;
FIG. 36 a is a view similar to FIG. 35 a with the microchip only coated in sections;
FIG. 36 b is a view similar to FIG. 35 b with the microchip only coated in sections;
FIG. 37 a is a view similar to FIG. 35 a with a silicone coating on the membrane;
FIG. 37 b is a view similar to FIG. 35 b with a silicone coating on the membrane;
FIG. 38 is a schematic side view of a housing with a membrane and a pressure foot held on the microchip and supported on the membrane;
FIG. 39 is a schematic perspective view of the arrangement of the microchip and pressure foot according to FIG. 38 ;
FIG. 40 is a schematic sectional view through a housing with the membrane and a U-shaped clip-type spring between the microchip and membrane;
FIG. 41 is a schematic view of the arrangement of the microchip and leaf spring according to FIG. 40 ;
FIG. 42 is a view similar to FIG. 40 in the case of an exemplary embodiment with a clip and two pressure feet;
FIG. 43 is a view similar to Figure 40 with a clip having a lateral crosspiece;
FIG. 44 is a view of the arrangement comprising microchip and clip according to FIG. 43 ;
FIG. 45 is a sectional view through an insert receiving a measurement chamber with a membrane closing off the measurement chamber, and
FIG. 46 is a sectional view through a housing with an insert inserted into the housing according to FIG. 45 .
DETAILED DESCRIPTION
As already explained, the implantable device for determining intracranial pressure comprises a rigid housing 1 with an interior 2 , which is closed off to the outside by means of a flexible, preferably elastic membrane 3 . The rigid housing is configured so that it is as free from deformation as possible at the occurring pressures. It can be made, for example, of ceramic, a biocompatible plastic (polyether ether ketone, polyether ketone ketone) or of metal (titanium, titanium alloy) and can additionally have an internal reinforcement structure, e.g. by supports passing through the interior or reinforcing ribs on the housing 1 , which are not shown in the drawing.
The wall thickness of the housing lies between 0.3 millimeters and 2 millimeters, whereas the thickness of the membrane is considerably smaller, e.g. in the order of between 0.005 millimeters and 0.05 millimeters.
To produce the membrane, a single-piece housing can be worked from in particular, which is reduced in thickness in a specific wall region by a machining operation or in another way. A housing is then obtained that has very highly deformation-resistant walls, the wall thickness only being reduced in the region of the predetermined wall region by the mechanical premachining.
The wall in the predetermined wall region is then further reduced in thickness, i.e. by means of a chemical etching process or by an electrolytic removal process, until the desired thickness of the membrane is reached.
FIGS. 33 a and 34 a show possible geometries of the predetermined wall regions 10 , which are produced by a machining process, e.g. by milling or hollowing out. In this case, the remaining thickness of the material in the predetermined wall regions 10 is configured differently. In the exemplary embodiment of FIG. 33 a , for example, a stepped depression 9 is arranged in the central wall region, in the exemplary embodiment of FIG. 34 a a trough-like depression 9 with raised edges 7 is arranged. Thus, a membrane 3 with a thickness that is smaller in the central region than in the edge region is obtained after the etching process. If one works from a geometry according to FIG. 33 a , then after the etching process a cross-section is obtained such as that shown in FIG. 33 b , i.e. a cross-section with a stepped depression in the central region, if one works from a geometry such as that shown in FIG. 34 a , a membrane with a cross-sectional face in keeping with FIG. 34 b is obtained, i.e. with a central trough that merges without any step into the membrane surface.
The interior 2 or at least a part thereof is filled with a transfer medium, e.g. a gas or a liquid. By means of this transfer medium pressure fluctuations of the surrounding area that lead to a deformation of the membrane 3 are transferred to the interior 2 and there, inter alia, also to a microchip 4 arranged in the interior 2 ( FIG. 5 and FIG. 5 a ).
The transfer medium 5 can preferably also be a vulcanised or polymerised plastic material, e.g. a cross-linked silicone, into which the microchip 4 is sealed and which completely fills the entire cavity between the microchip 4 and the inside wall of the housing 1 , as is shown schematically in FIG. 5 .
In particular when a gas is used as transfer medium, it is favourable if the interior 2 is configured with a very small volume, as is shown in FIG. 4 .
In principle, different measurement sites are established for the measurement of intracranial pressure. In most cases intraventricular measurement is recommended, corresponding exemplary embodiments are also conceivable for parenchymal, epidural or subdural measurement.
For intraventricular pressure measurement it is specifically recommended to use a titanium tube with an outside diameter of about 3 mm, which corresponds to the dimensions of a typical ventricle catheter normally used in hydrocephalus therapy. The housing is closed at the ends by a hemisphere. A window, which is closed again with an extremely thin metal foil, is formed in the cylindrical housing wall to be as close as possible to this semicircular tip (preferably about 1 to 3 mm away). The wall of the metal tube, which is made from a biocompatible material, has a thickness about 10-times that of the foil covering the window, but can also be configured to be even thicker. The thickness of the foil preferably amounts to 0.01 mm, the wall thickness of the tube 17 to 0.1 mm. The foil 21 is curved in keeping with the shape of the tube or clamped flat over the opening and welded to the tube, for example, by a laser welder to be gastight.
The welding can preferably be performed with the aid of a clamping sleeve 16 . FIG. 8 shows the structure of such a clamping sleeve. FIG. 6 shows the structure of a pressure sensor with clamping sleeve 16 , microchip 4 , electronics 12 , 13 and air chambers 15 , 20 , 22 . The clamping sleeve 16 has an inside diameter corresponding to the outside diameter of the tube 17 (thus of the housing). The thin foil 21 can be placed over the window in the tube 17 and secured by means of the clamping sleeve 16 . The clamping sleeve 16 has an identical window to that of the tube 17 . The clamping sleeve 16 is placed over the window so that the two windows lie precisely one over the other, wherein the window of the tube 17 is covered by the titanium foil. By welding the clamping sleeve 16 to the tube 17 along the outer edge 24 , a gastight welding of the foil 21 , tube 17 and clamping sleeve 16 is achieved. The quality assurance is achieved by means of a helium leak indicator.
The tube 17 is closed at the end with a cap 19 and welded. The electronic components are positioned on a support 11 , and the transmission of the measurement signal is assured by a cable connection 23 to a coil 29 .
FIG. 10 shows an overview of the implantable device. The externally prevailing pressure is transferred to the inside chamber 35 by way of the window 28 closed by the foil 21 and is measured by means of the electronic unit 34 . A cable 31 passes the signal to the coil 29 . A suitable shape of the housing 33 allows the housing 33 to be located in a drill hole in the cranium with a precise fit. The housing 33 is filled with a filler (preferably plastic, ceramic or metal) 32 as far as possible so that the space of the inside chamber 35 filled with gas is minimally small, so as to assure the most sensitive possible pressure transfer through the window 28 .
FIG. 7 shows an exemplary structure of a pressure window. The membrane or foil 21 is sealed to be gastight by means of the weld of the outer edge 24 with the clamping sleeve 16 and the tube 17 . An air chamber 22 , which is designed to be minimally small and which is connected to a chamber 20 ( FIG. 6 ) by means of a duct-like air chamber 15 , is located under the foil 21 . The filler material 18 assures a minimally small air volume in the chambers 20 , 22 and the air chamber 15 .
FIG. 9 shows a top view of the ventricle sensor with the cap 19 , the welded outer edge 24 , the clamping sleeve 16 , the window with the thin foil 21 as well as the tube 17 . FIG. 8 shows an exemplary embodiment for a clamping sleeve 16 .
As shown in FIG. 5 , the microchip can be an integrated chip, which has multiple function regions. One function region can be a pressure-sensitive sensor 41 , for example, next to this other sensors 42 , 43 , 44 are indicated, e.g. one of these sensors can be a temperature sensor.
In addition, the microchip has an analog-to-digital converter 45 , in which the analog electrical signals generated by the sensors are converted into digital signals.
In the shown exemplary embodiment, a digital sequential control means 46 is additionally provided as well as an identification panel 47 , in which an unalterable, readable identification of the microchip 4 can be stored, by means of which the microchip 4 and thus the entire implantable device can be identified.
Finally, signal transmission elements 48 can be integrated into the microchip 4 .
In the exemplary embodiment of FIG. 5 a , a support 37 is additionally represented in the housing 1 in the form of a bend-resistant thin plate, on which the microchip 4 is attached, e.g. adhered. In addition to the microchip 4 the support 37 carries further electronic components 38 , e.g. diodes or capacitors for power limiting, wherein these are passive electronic components in particular. Moreover, strip conductors 39 and band-type contacts 40 are arranged on the support 37 that connect the microchip 4 and the components 38 and also connect the components 38 to one another.
In all the embodiments it is possible to either arrange only one microchip in the housing 1 , as is evident from the representation of FIG. 5 , or a support 37 , on which besides the microchip 4 further components 38 such as strip conductors 39 and contacts 40 are arranged.
In all the exemplary embodiments illustrated below this support can be additionally added to the microchip, but this is only shown in the drawings in the exemplary embodiment of FIG. 5 a.
The microchip 4 can be arranged in the tube 17 in the same way as has been explained on the basis of FIG. 6 .
However, it can also be provided that the housing 1 is so small in configuration that it is just large enough to receive the microchip 4 , as is shown schematically in the example of FIG. 5 . In this case, the microchip 4 fills almost the entire interior of the housing 1 , the remaining interior space being filled with the transfer medium 5 , in particular with a cross-linked silicone or a highly viscous oil. The sensors 41 to 44 and in particular the pressure-sensitive sensor 41 are located approximately in the centre of the housing 1 , as is also shown in FIG. 5 . The housing 1 can be cylindrical with an outside diameter in the order of between 2 and 5 millimeters, in particular about 3 millimeters, and a length of between 15 and 25 millimeters, in particular about 20 millimeters. Therefore, this is a very small structural unit, which can be placed in a simple manner at the desired position in the brain.
This placement can be achieved by means of a manipulation instrument 50 , as is shown schematically in FIGS. 16 to 19 . This is a tube 51 with a handle 52 , the outside wall of which has a through longitudinal slot 53 . The housing 1 is inserted into the tube 51 at the front end of the manipulation instrument 50 and is held there, e.g. by clamping. The manipulation instrument 50 with the housing 1 held therein is placed through a drill hole 54 in the top of the cranium 55 at the desired location of the brain 56 ( FIG. 17 ), and the manipulation instrument 50 is then pulled back out of the drill hole 54 , wherein the housing 1 remains in the brain 56 ( FIG. 18 ). In this case, the longitudinal slot 53 serves to insert a connection cable 57 arranged on the housing 1 into the tube 51 and pull this out again after placement of the housing 1 , so that the manipulation instrument 50 can be completely separated from the housing 1 after it has been located ( FIG. 19 ).
FIG. 11 shows the housing 1 placed in the brain 56 in this manner and a connection cable 57 , which leads from the housing 1 onto the outside of the top of the cranium 55 and is connected to a coil 58 , which is laid externally on the top of the cranium 55 , i.e. between the top of the cranium 55 and the scalp 59 , or in an alternative embodiment externally on the scalp 59 . FIG. 12 shows both alternatives by showing the scalp 59 twice, namely once on one side and once on the other side of the coil 58 .
This coil 58 can be coupled inductively to a transmission coil 60 , which is brought externally onto the scalp 59 , so that an electrical connection can be created by means of the two coils 58 and 60 to an evaluation unit 61 , which is connected to the transmission coil 60 by means of a line 62 .
The coil 29 in the exemplary embodiment of FIGS. 6 to 10 is connected to an evaluation unit in a similar manner.
However, this connection can also be replaced by an electrical connection, with which the connection cable 57 coming from the housing 1 is not connected to a coil 58 , but directly to an evaluation unit outside the body, e.g. one carried on the body. In this case, the connection cable 57 passes through the scalp.
In the exemplary embodiment of FIGS. 6 to 10 , the coil 29 is embedded into the housing 33 , so that an electrically conductive connection between the microchip 4 and the coil 29 can be made inside the housing.
The situation is different in the configurations of FIG. 5 or 5 a , in which only the microchip 4 or the support 37 with the microchip 4 are arranged in the housing 1 , a connection cable 57 that must be guided out of the housing 1 is necessary here. This bushing is configured so that the interior of the housing 1 is hermetically sealed in this exit region. This can be achieved, for example, by means of a support made of ceramic or plastic, which is inserted into the housing wall and is sealed relative to this and into which electrical contacts are embedded. An adhesive or gold solder can be used for sealing.
The connection cable 57 can be permanently connected to the contacts of the hermetic duct, e.g. by soldering, welding, contact adhesion, crimping or other connection techniques known per se.
In another configuration a releasable connection can also be provided between the hermetic duct and the connection cable, e.g. by using a plug connection. Such a plug contact 63 , which passes tightly through the wall of the housing 1 and to which the connection cable 57 can be attached by means of an appropriate counterpart 64 , is schematically shown on the housing 1 in the exemplary embodiment of FIG. 12 .
An exemplary embodiment of such a plug contact 63 and a corresponding counterpart 64 is shown in FIG. 13 .
The plug contact 63 arranged on the housing 1 has an externally threaded stem 65 , which bears two contact regions 66 , 67 electrically insulated from one another, which connect to the microchip 4 via separate lines.
The counterpart 64 has an internally threaded stem 68 , so that the counterpart can be screwed onto the externally threaded stem 65 . When these are fully tightened, two contact regions 69 and 70 come into electrically conductive abutment against the contact regions 66 or 67 , so that an electrical connection is created in these contact regions. The contact regions 69 and 70 of the counterpart 64 are connected to conductors 71 , 72 of the connection cable 57 .
After tightening, the counterpart 64 completely closes off the externally threaded stem 65 and seals this relative to the surrounding area. This results not only in a hermetically tight bushing through the wall of the housing, but also a hermetically tight connection of the plug contact 63 with the counterpart 64 .
This connection can naturally also be configured as a simple plug connection, therefore the term plug contact is used. However, the described screw connection is advantageous, because any unintentional release of the connection is prevented as a result.
FIG. 14 shows an exemplary embodiment of such a housing 1 , which receives in its interior the microchip 4 that connects directly with contact pins 74 , 75 . These pass tightly through a support 75 , which is inserted tightly into the wall of the housing 1 and on which a counterpart 64 is attached. The contact pins 73 , 74 can also be permanently connected directly to the connection line, e.g. by welding, soldering, contact adhesion, crimping or other techniques.
In its remaining interior the housing 1 is filled with a highly viscous oil or a cross-linked silicone and transmits movements of the membrane (not shown in FIG. 14 ) onto the sensors of the microchip 4 in the described way.
The entire arrangement shown in FIG. 14 has a diameter in the order of 3 millimeters and a length in the order of 20 millimeters, i.e. constitutes a very small structural unit.
If the connection cable 57 is connected to a coil 58 at its end remote from the housing 1 , then this can be achieved in a manner clearly shown in the representation of FIG. 15 . The coil is received in an annular housing 76 that is closed on all sides, the connection cable 57 feeds laterally into the housing 76 to form a seal and is connected to the coil 58 there. A very flat arrangement results, which can be placed in this form on the cranial bone, i.e. between the cranial bone and the scalp, as is clear from the representation of FIG. 11 .
Power can be supplied to the microchip 4 from the outside via the coil 58 and the connection cable 57 , so that the microchip does not require a power supply of its own. On the other hand, digital signals generated by the sensors of the microchip 4 can be transmitted via the connection line to the evaluation unit. The connection cable 57 thus constitutes a power and signal transmission line.
A further preferred embodiment of an implantable device for intracranial pressure measurement is shown in FIG. 20 et seq. In this case, the housing 1 of this device is in the form of a shallow can with a plane floor surface 80 and an upper side 81 that is also plane in the exemplary embodiment shown. In this case, the housing is circular in cross-section with a diameter of between 1 cm and 3 cm, the height amounting to between about 2 mm and 5 mm. The housing 1 is divided into an upper measurement chamber 83 and a lower fluid chamber 84 by an intermediate wall 82 running parallel to the floor surface 80 . The intermediate wall 82 is opened in the central region, and this connection region 85 between the measurement chamber 83 and the fluid chamber 84 is closed off by the membrane 3 .
At the lower end of the fluid chamber 84 a pipe connection 86 exits in the centre of the housing 1 to project vertically downwards, and this is connected to an elongated tube 87 that forms a catheter.
A microchip 4 is arranged in the measurement chamber 83 , as in the housings of the above-described embodiments, the measurement chamber 83 being filled with a transfer medium 5 , preferably a cross-linked silicone. In this way, the pressure of a liquid in the fluid chamber 84 can be measured by means of the membrane 3 and a corresponding measurement signal can be generated.
The described device is placed on the head in such a manner that the tube 87 is advanced at its free end in the manner of a catheter to the location of the brain, at which the intracranial pressure is to be measured. The housing 1 lies on the outside of the top of the cranium 55 with its floor surface 80 , the pipe connection 86 and the tube 87 then project through the drill hole 54 in the top of the cranium 55 , as is shown schematically in FIG. 20 . The housing 1 thus serves as a drill hole covering. The tube 87 is open at its end remote from the housing 1 and thus allows brain fluid to flow into the fluid chamber 84 . When completely full, the pressure of the brain fluid at the location of entry is transferred via the membrane 3 to the microchip 4 in the measurement chamber 83 .
However, as shown in FIG. 29 , the tube 87 could also be closed and have an opening 90 closed by a membrane 89 at its closed end 88 . In this embodiment, the fluid chamber 84 and the tube 87 are filled with a further transfer medium, e.g. a liquid, and the pressure of the surrounding brain fluid is transferred via the membrane 89 to the liquid filling in the fluid chamber and in the tube 87 . In this way, the pressure is transferred by the transfer medium to the membrane 3 and thus to the microchip 4 .
The digital signals generated by the microchip are transmitted to the transmission coil 60 either via a coil 91 arranged in the measurement chamber 83 or are passed electrically or inductively to the evaluation unit by means of a connection cable 57 directed out of the housing 1 to form a seal.
In the exemplary embodiments of FIGS. 22 , 23 , 25 and 26 , the coil 91 surrounds the microchip concentrically inside the measurement chamber 83 , so that a particularly favourable division of space results, which contributes to a small structural size of the housing 1 .
In contrast, a connection cable 57 leading out of the housing 1 is provided in the exemplary embodiments of FIGS. 30 , 31 and 32 . In this case, the housing 1 is provided with a sealed cable duct 92 in the exit region that can also be configured in the manner explained on the basis of the other exemplary embodiments. The connection cable can lead directly to a coil 93 , which is placed on the outside of the top of the cranium 5 outside the housing 1 , i.e. either at a distance from the housing 1 next to this ( FIG. 31 ) or to concentrically surround the housing 1 ( FIG. 32 ).
Naturally, the connection cable 57 could also be directly electrically connected to the evaluation unit 61 .
The described design is suitable in particular for determining the fluid pressure in a drainage system for the treatment of hydrocephalus. FIG. 22 shows an overview diagram of such a structure. With this device, the measurement chamber of which is of similar structure to that in the exemplary embodiment of FIG. 6 , but additionally receives a coil 91 , the intermediate wall 82 is replaced by the membrane 3 , i.e. the membrane 3 extends over the entire cross-section of the housing 1 and divides the interior of the housing 1 into the measurement chamber 83 and the fluid chamber 84 . Such a configuration can also be used in the other can-shaped housings 1 , but a configuration with an intermediate wall 82 and a membrane 3 inserted into this can also be used in all such can-shaped housings.
In the exemplary embodiment of FIG. 22 two pipe connections 94 , 95 running parallel to the floor surface 80 branch off from the fluid chamber 84 on opposite sides, one of which pipe connections is connected to a tube 87 and forms the liquid supply pipe, whereas the other can be connected to a liquid drainage pipe, which is only shown schematically in FIGS. 31 and 32 . Thus, the brain pressure fluid can flow out of the interior of the cranium through the fluid chamber 84 and be removed from the interior of the cranium, as is usual in drainage systems for the treatment of hydrocephalus. As shown schematically in FIG. 27 , a non-return valve 97 can be inserted into a drainage pipe 96 , the drainage pipe can terminate in a reservoir 98 , in which the drained liquid is collected. This reservoir can be used, for example, to backwash and clean the liquid pathways.
In the case of a housing 1 with a supply conduit entering the fluid chamber 84 parallel to the floor surface 80 , it is favourable not to arrange the housing 1 directly above a drill hole 54 , but laterally next to a drill hole, so that the drill hole remains free for the passage of the supply conduit, as is shown in FIG. 28 . A separate drill hole covering 100 can then be provided in the region of the drill hole 54 .
In the exemplary embodiment of FIG. 22 both pipe connections 94 and 95 run parallel to the floor surface, but arrangements such as shown in FIG. 23 are also possible. In this case, a pipe connection 94 flows from below vertically to the floor surface 80 centrally into the fluid chamber 84 , whereas the second pipe connection 95 exits laterally parallel to the floor surface. Such a device is used in the manner described in FIG. 24 , so that the tube 87 projects through the drill hole 54 in the top of the cranium 55 into the interior of the cranium, in which case the housing 1 covers the drill hole 54 . The housing 1 is arranged between the top of the cranium 55 and the scalp 59 , a drainage pipe 96 can run directly on the top of the cranium 55 and under the scalp 59 .
A similar arrangement is described in FIG. 25 , wherein a protective cap 99 additionally engages over the housing 1 , so that both the housing 1 and the surrounding tissue are additionally protected.
If a vulcanised or polymerised material, in particular a cross-linked silicone, is used as transfer medium inside the housing 1 , then the entire cavity between the microchip 4 and the membrane 3 can be filled with this material, so that a pressure transfer then occurs over the full surface.
However, it is also possible that the pressure transfer occurs only in a sub-region of the microchip.
In the exemplary embodiment of FIG. 35 a it is shown that the microchip is covered over the full surface by such a vulcanised or polymerised material, hereafter abbreviated to transfer material, but that this transfer material has a greater thickness in the region of the pressure sensor 41 . In the installed state, the microchip 4 and the membrane 3 lie so close together that in this central region, in which the transfer material has a greater thickness, this material abuts against the membrane 3 , as is shown in FIG. 35 b , so that a pressure transfer occurs in this region. This pressure transfer is therefore concentrated onto the region of the pressure sensor 41 .
It is also possible that according to the configuration of FIGS. 36 a and 36 b only the region of the pressure sensor 41 is encased by the transfer material, whereas externally located edge regions of the microchip remain free of the transfer material.
Finally, it is possible that the microchip is not coated at all with the transfer material, instead the transfer material is arranged on the membrane 3 , so that a pressure-transferring layer of the transfer material is formed between the membrane 3 and the pressure sensor 41 as a result.
Finally, it is also possible in a modified exemplary embodiment to conduct the pressure transfer by means of mechanical pressure transfer elements, e.g. by a pressure foot 101 , which is disposed on the microchip 4 and is supported against the membrane 3 , as is shown in FIGS. 38 and 39 . This pressure foot 101 then transfers the pressure forces from the membrane 3 to the pressure sensor 41 .
A spring element, e.g. a U-shaped leaf spring 102 , which is supported against the pressure sensor 41 on one side and against the membrane 3 on the other, as is shown in FIGS. 40 and 41 , can also be inserted between the microchip 4 and the membrane 3 in place of the pressure foot 101 . Such a leafspring 102 can be disposed on the housing 1 or on a support 37 holding the microchip 4 by means of lateral crosspieces 103 .
FIG. 42 shows a modified design for a mechanical pressure transfer element, namely a clip 104 , which is disposed on the housing 1 or a support 37 , and which is supported on the membrane 3 by means of a first foot 105 and on the pressure sensor 41 by means of a second foot 106 and in this way transfers the pressure forces from the membrane 3 to the pressure sensor 41 .
As may be seen from FIGS. 43 and 44 , such a clip 104 can bear lateral crosspieces 107 , which act as a stop and which restrict movement of the clip 104 to thus prevent overload and damage to the entire arrangement. Such stops can be provided in all arrangements that transfer the pressure forces mechanically to the pressure sensor 41 .
A further possible configuration for a rigid housing 2 is shown in FIGS. 44 and 45 . In this case, as in the exemplary embodiment of FIG. 23 , the rigid housing 2 is provided with a pipe connection 94 that opens centrally and vertically therein from below and with a pipe connection 95 that exits horizontally and radially and is open at the upper side. An insert 109 , which tightly closes the housing 2 on the upper side, is inserted into the upper side that is open at the top. The insert 109 receives the microchip 14 as well as electronic unit 12 and electronic unit 13 in a similar manner to the transfer medium 5 in the exemplary embodiment of FIG. 5 . On its underside the insert 109 has a plane circumferential edge 110 , which runs along its outer contour and projects downwards beyond it only very slightly. The plane membrane 3 configured as a thin metal foil is laid flat against this planar rim 110 and is clamped between the insert 109 on one side and an annular abutment element 111 on the other side, which lies opposite the edge 110 and terminates with this on the outside.
The insert 109 and the membrane 3 are soldered or welded together in the region of the abutment element 111 and the edge 110 .
To create this connection, the membrane 3 is firstly arranged to abut flat against the edge 110 before being inserted into the housing 2 and is pressed against the edge 110 by means of the abutment element 111 , i.e. by means of a contact pressure K ( FIG. 45 ). In this case the dimension of the membrane is selected so that this projects laterally slightly beyond the insert 109 and the abutment element 111 , as is clear from FIG. 45 . The soldering or welding to the insert 109 and the abutment element 111 occurs in this region of the slightly projecting edge of the membrane 3 . In particular, in the case of a welding process the projecting edge region of the membrane can be removed during the welding, so that a flush closure of the membrane 3 with the insert 109 and the abutment element 111 can be achieved.
This structural unit with the welded or soldered membrane 3 is then inserted into the upwardly open housing 2 and seals this as a result. The still unoccupied interior of the housing 2 then forms the fluid chamber 84 , through which the brain fluid flows, the pressure of which is to be determined.
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To assure, in the case of an implantable device for determining intracranial pressures, the biocompatibility of the implant in the long term, wherein a pressure measuring device is used, which is operatively connected to a sensor for a telemetric measured value transfer, it is proposed that the pressure measuring device is a microchip, that the microchip is located in a rigid housing, and that the pressure transfer from the outside inwards occurs through a very thin biocompatible membrane, the pressure-dependent movement of which acts on the pressure measuring device via a transfer medium.
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The present invention relates in general to the art of inductance measuring, and it relates in particular to a new and improved method and circuit for providing a direct readout of the inductance value of a coil.
BACKGROUND OF THE INVENTION
The method which was heretofor most commonly used to measure the inductance of a coil made use of an impedance bridge wherein several impedance values were adjusted to provide a minimum or null reading on a highly sensitive meter. After balancing the meter the inductance value was then read from a dial associated with one of the adjustable impedances. While such a method is well suited for use in laboratories, it is too time consuming for field use in the servicing of electronic equipment. Moreover, the required bridge components are relatively bulky and expensive, and considerable skill is required to balance the bridge and read the inductance value from the dial.
By definition the inductance value of an inductor is: ##EQU1## It would be desirable to provide a method and circuit for utilizing this basic equation to provide a simple and direct measurement of the inductance of a coil.
SUMMARY OF THE INVENTION
Briefly, in accordance with the broader aspects of the present invention ramp pulses of linearly varying current are applied to a coil under test to develop a peak voltage across the coil during occurrence of the pulses, which peak voltage may be calculated using the following equation:
Vp=L di/dt+I.sub.max R.sub.L
wherein:
L is the inductance value of the coil.
I max is the peak current through the coil during each pulse.
R L is the resistance of the coil.
di/dt is a constant throughout the duration of each pulse.
This peak voltage value, V p , is stored in a capacitor while a steady state current equal to I max is applied to the coil between the ramp pulses. Consequently, between ramp pulses the voltage developed across the coil is as follows:
Vs=I.sub.max R.sub.L
It will be apparent that
Vp-Vs=L di/dt
Therefore, for a given constant value of di/dt
Vp-Vs=KL
This difference or output voltage is applied to a voltmeter having its output calibrated directly in Henrys so that the meter automatically provides a direct reading of the inductance value of the coil under test.
In order to facilitate a reading of inductance, it is desirable to employ a meter having a digital readout, and in order to minimize the number of digit readout elements required, there is provided in accordance with another aspect of the invention means for using different values of di/dt for different ranges of inductance value. In this manner a readout of the three most significant digits is provided for a wide overall range of inductance values. In a commercial embodiment of the invention the overall range is from about 0.1 μH to about 10 H.
GENERAL DESCRIPTION OF THE DRAWING
The present invention will be better understood by a reading of the following detailed description taken in connection with the accompanying drawing wherein:
FIG. 1 is a block diagram of an inductance measuring circuit embodying the present invention;
FIG. 2 is a plurality of wave forms useful in understanding the invention; and
FIG. 3 is a schematic diagram of an inductance measuring circuit constituting a preferred embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 1, a coil or other inductance device 10 whose inductance value is to be measured is connected in series with a spring biased, normally open switch S1 across a diode 14 having its positive terminal connected to ground. When the switch S1 is closed the inductance value of the coil 10 is shown by a digital display 15. In a preferred embodiment of the invention the display has three digits and displays the three most significant digits of a wide range of inductance values.
In accordance with the present invention, a main control circuit 16 of any suitable construction produces a wave form of voltage A as shown in FIG. 2. The wave form A comprises a train of positive rectangular pulses each having a substantially square trailing edge. The wave form A voltage is applied to the inputs of a plurality of voltage ramp generators 18A-18N. Each generator 18 responds to the negative going transition or trailing edge of the wave form A voltage to provide a linearly increasing voltage during a first period of time from t o to t 1 as shown in FIG. 2 and to provide a steady state voltage during a second period of time from t 1 to t 4 . The output wave form of voltage for one of the ramp generators 18 is illustrated as waveform B in FIG. 2. The number of generators 18 which are used will depend on the range of inductance values for which the particular instrument is designed. Each of the generators 18 produces an output waveform having a different slope in the time period between t o to t 1 as is more fully described hereinafter.
A range selector switch 20, which can be operated manually or automatically, connects the waveform B voltage from a selected one of the ramp generators 18 to the input of a voltage to current converter 22 which thus has an output current waveform of the same basic shape as waveform B. The output current from the voltage to current converter 22 is passed through the coil 10 under test to develop across the diode 14 a voltage having a waveform C as shown in FIG. 2. This voltage waveform C is applied to the inputs of a pair of selectively operated peak voltage detectors 24 and 26 having their respective outputs coupled to a difference amplifier 28. The amplifier 28 provides a d.c. output voltage equal to the difference between the two input voltages applied to its inputs and this output voltage is measured by a digital voltmeter circuit 30 which drives the digital readout or display 15.
The peak voltage detector 24 has a d.c. output voltage proportional to the maximum or peak voltage developed across the coil 10 during the period of time from t o to t 1 . Hence the control circuit 16 enables the peak detector 24 in synchronism with the negative transition of the waveform A and disables the peak detector 24 at time t 1 when the voltage of waveform B reaches its maximum and steady state value. To this end, a control or gating voltage of waveform D as shown in FIG. 2 is applied to the peak detector 24 from the control circuit 16.
The peak detector 26 has a d.c. output voltage proportional to the voltage developed across the coil 10 during the second period from time t 1 to time t 4 while a steady state d.c. current is passed through the coil 10 under test. Hence the control circuit 16 enables the peak detector 26 during the time period from t 2 to t 3 as shown in FIG. 2 by applying a control or gating voltage of waveform E to the peak detector 26.
The peak detector and storage devices 24 and 26 store the peak voltages applied thereto for a period greater than the repetition period of the pulses of waveform A wherefor the voltage measured by the digital voltmeter 30 is proportional to the difference in the peak or maximum voltages across the coil 10 during the first and second periods. As explained hereinabove, this difference voltage is proportional to the inductance value of the coil 10 wherefor the digital display 15 displays the inductance value of the coil 10 while the switch 12 is held in the closed position.
As briefly mentioned above, the instrument of the present invention displays on a three digit display the three most significant digits of the measured inductance values within a wide range of values. In accordance with this aspect of the invention a first ramp generator 18A is used when inductance values between 0 μH and 99.9 μH are measured, a second ramp generator is used when inductance values between 1 μH and 999 μH are measured and so on. It may thus be seen that six ramp generators are required in an instrument for measuring inductance values in the range of 0 to 9.99 H.
In order to facilitate a better understanding of the present invention and of the operation of the inductance measuring instrument of FIG. 1, assume that the coil under test has an inductance of 50 mH and a resistance of 20 ohms. For measuring inductance values in the range of 1 mH to 999 mH the generator 18 whose ramp portion has a slope of 10 volts/millisecond is selected and the ramp portion of the current wave passed through the coil 10 has a slope of 10 ma/m sec. This current has a steady state value between times t 2 and t 3 of 6 mA.
During the first period between t o and t 1 , the peak voltage developed across the coil 10 is therefore: ##EQU2##
During the second period when the current passed through the coil 10 is constant, di/dt is zero wherefor the voltage developed across the coil 10 is: ##EQU3##
Since the voltage output of the difference amplifier is
V.sub.D =V.sub.P -V.sub.S
V.sub.D =0.620 volt-0.120 volt=0.500 volt.
The readout or display 15 will thus display the digits 5-0-0. The display is graduated and decimalized to show that the actual inductance value is 50.0 m.h.
If, for example, a coil 10 having an inductance of 525 μH and a resistance of 2 ohms were to be tested, the ramp generator 18 whose ramp portion has a slope of one amp/msec would be selected. Hence the peak voltage detected during the ramp portion of the applied current would be:
V.sub.D =L di/dt+I.sub.max R-I.sub.max R=(0.000525 H)(1000 A/sec)+(0.006)(2)-(0.006)(2)
V.sub.R =0.525 Volts
The readout 15 will thus display the digits 5-2-5 which is graduated to read 525 μH or 0.525 mH.
Referring now to FIG. 3 wherein is shown the schematic diagram of an inductance meter embodying several novel features of this invention, the same reference characters as used in FIG. 1 are used to denote the corresponding function blocks in FIG. 3. The ramp voltage generator circuit 18 shown in detail in FIG. 3 is for measuring inductance values in the range of from one to 100 MH and thus provides a ramp portion from t o to t 1 having a slope of 10 amps/sec.
The control circuit 16 is energized from a standard 60 Hz power line and shapes the line frequency power to form the three control signals shown by waveforms A, D and E. The line voltage which is applied between input terminal 32 and ground is coupled by a transistor TR1 to both inputs of a plurality of NAND gates 34 to provide a voltage having the shape of waveform A. This voltage is coupled via a diode D1 to the inputs of the plurality of ramp voltage generators 18.
When the voltage applied to the input of the generator 18 goes low, capacitor Co is permitted to charge from a 20 V power supply bus. The transistor TR2 controls the charging current whereby the voltage across the capacitor Co increases linearly until the voltage at the collector of the transistor TR2 reaches 12 volts and a Zener diode 36 becomes conductive to prevent and further charging of the capacitor Co. The adjustable resistor 38 connected between the capacitor Co and the -3 V power supply terminal is used to calibrate the instrument for each inductance range by adjusting the slope of the voltage across the capacitor Co during charging.
When the Zener diode 36 conducts a positive voltage is applied to the positive input of an amplifier A1 causing its output to go high. The output of the amplifier A1 is applied to one input of a NOR gate 40, the other input having the voltage shown in waveform D applied to it from the control 16. Hence when the Zener diode 38 conducts, the control voltage applied to the peak detector 24 goes low.
The signal which is illustrated in waveform E and which is used to control the peak detector 26 is also derived from the 60 Hz power line voltage by the control circuit 16. As shown, the power line voltage is applied to the base of a transistor TR3 which drives a pair of cascaded NAND gates 41 thereby to provide the positive voltage pulse during the period from t 2 to t 3 .
The waveform B voltage which appears at the collector of the transistor TR2 is transmitted by a diode D2 and the range selector switch 20 to the emitter of the transistor TR4 in the voltage to current converter 22. The collector of the transistor TR4 is connected to the junction between the switch S1 and the diode 14 and also to the positive input terminal of an amplifier A2. The voltage at the output of the amplifier A2 is equal or proportional to the voltage across the coil 10 under test when the switch S1 is closed and this voltage is applied to the input terminals of a pair of solid state switches 42 and 44 respectively provided in the peak voltage detectors 24 and 26. A capacitor C1 is connected between the ground and the output of the switch 42 and a capacitor C2 is connected between ground and the output of the switch 44. Therefore, while the control voltage to the switch 42 from the NOR gate 40 is high, the capacitor C1 charges up to the voltage across the coil 10, and while the control voltage to the switch 44 is high the capacitor C2 charges up to the voltage across the coil 10.
A pair of buffer amplifiers A3 and A4 respectively couple the voltage across the capacitors C1 and C2 to the inputs of the difference amplifier 28 which includes the amplifier A5 whose output is connected to a conventional digital voltmeter circuit which drives the digital readout. The voltage at the output of the amplifier A5 is, as explained hereinabove, proportional to the inductance value of the coil 10 under test, wherefor the three digit number displayed by the digital readout is the inductance value of the coil 10.
While the present invention has been described in connection with a particular embodiment thereof, it will be understood by those skilled in the art that many changes and modifications may be made without departing from the true spirit and scope of the present invention. Therefore, it is intended by the appended claims to cover all such changes and modifications which come within the true spirit and scope of this invention.
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A direct reading inductance meter applies linearly increasing ramp current pulses to a coil under test and compares the voltage developed across the coil during occurrence of the pulses with the voltage developed across the coil while a steady state current is applied to the coil thereby to provide an output voltage having a value directly related to the inductance of the coil.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of continuous heat treatment designed to improve the quality of the surface of the sheet, in particular cold rolled steel sheet.
2. Description of the Prior Art
In industrial practice, cold rolled steel sheet is obtained (after preparation of the steel and hot rolling of the strand or slab) by pickling of the hot-rolled strip followed by cold rolling to the required thickness and finally by annealing in order to restore the mechanical properties of the steel and by a skin-pass to provide the steel with the required final surface finish and to remove the yield plateau of the tensile test curve.
All the operations following hot rolling have an effect on the final surface condition of the sheet. Thus, inadequate rinsing after pickling may provide the possibility of subsequent contamination. In the same way, the selection of the rolling oil is extremely important to the extent that this oil may not be removed from the surface of the sheet if the annealing process is not suitably adapted to this.
Several authors have given sufficient proof of the fact that the surface cleanness of steel sheet (more particularly the amount of carbon deposited) is an important parameter in explaining the suitability of this sheet for phosphate coating and its resistance to corrosion by salt spray after painting. Such surface cleanness may be tested in several ways, for example by the adhesive tape test in which transparent adhesive tape is applied to the surface of the sheet and then removed with possible deposits taken from the sheet. It is possible to measure the absorption of the light passing through the tape and therefore to quantify the surface deposits on the sheet. A method of this type provides a measurement of the amounts of deposits of all types on the surface, for example, dust, carbon traces, filings, etc.
A further method of testing the surface quality, which is also extremely widespread, consists in quantifying the total amount of carbon present on the surface of the steel. This involves washing the surface of the sheet with hydrochloric acid by means of pads of inorganic material which is then "burnt" with oxygen and the amount of CO 2 released is measured. It is therefore possible to measure the total amount of carbon present in various forms on the surface of the steel in mg/m 2 . It is also possible, for the purpose of standardizing tests, to utilize a power wash (with jets) before the hydrochloric acid washing in order to remove possible protective oils and to bring the sheet into the condition which it possesses after shaping and before phosphate coating and final painting. This is the case in the well-known as the "Ford test."
Further means of analysing the surface of steel are provided by the ion microanalyser, the Auger spectrometer, etc. These enable detection of all the chemical elements on the surface and the development of their concentration as a function of depth.
These techniques enable the detection of possible contamination by elements other than iron, these elements possibly being a result of the baths used (washing, pickling, rinsing, degreasing) or possibly being due to the steel itself.
As stated above, it is known at present that surface carbon on steel impairs resistance to corrosion by salt spray applied to the painted sheet. This carbon is deposited chiefly by the rolling oil. In current practice, the rolling oil is not removed from the surface of the sheet after rolling, but is evaporated during batch annealing. However, when the amount of surface carbon is measured after annealing of this type, it is possible to observe considerable contamination which leads to unfavorable phosphate coating and painting (exposure to salt spray) results.
Considerable progress has been made by subjecting the product to continuous annealing preceded by degreasing, for example by electrolysis in a solution of sodium orthosilicates.
In the case of simple continuous annealing, heating is in effect carried out under an N 2 /H 2 atmosphere and the oil does not have the time to evaporate, as the heating is very rapid. On the other hand, in several known methods, continuous annealing is preceded by a degreasing operation which is effected, in the majority of cases, in an alkaline medium. As the rolling oil has been eliminated before the sheet is placed in the furnace, the surface cleanness is considerably greater, in particular in respect of the total amount of surface carbon, which is decreased for example to 1 mg/m 2 to 8 mg/m 2 in the case of very clean sheet produced in a static furnace. However, as stated above, while such a decrease in the amount of surface carbon should, according to various authors, lead to an improvement in painting results, it has been observed that this improvement is not particularly great.
SUMMARY OF THE INVENTION
The object of the present invention is precisely to remedy this situation.
We have developed a method of applying continuous annealing with naked flame heating, of the type often used in the continuous galvanizing of steel strip, to sheet designed for automobile bodywork, and therefore designed for a double treatment of phosphate coating and painting. It is known that this type of heating is very suitable for the preparation of the surface for galvanizing, for which the basic requirement is the absence of any trace of oxides on the surface before immersion in the zinc bath. This type of heating has a greater or lesser oxidizing effect depending on the type of furnace used, and the possible oxide produced by passage through this furnace must be reduced by the hydrogen contained in the gas producing the atmosphere during the subsequent annealing-galvanizing steps.
The method of the invention is based on the surprising observation that non-degreased strip, i.e. strip on which the rolling oil is simply burnt off or evaporated in the naked flame furnace, has a considerably improved suitability for phosphate coating and painting in comparison with strip which is annealed after alkaline degreasing. Whilst carrying out this work, we have observed that, if combustion is controlled carefully, it is possible to produce an ultra-clean, non-oxidized strip which is highly resistant to salt spray after phosphate coating and painting. The examples given below elucidate this surprising effect further, this effect being due to the absence of the film of SiO 2 produced by degreasing in an alkaline bath before annealing, which film appears to retard the phosphate coating reaction.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The method of the present invention, in which metal sheet is subjected to a continuous heat treatment comprising a heating step and then a rapid cooling step, is essentially characterized in that the heating step is carried out at a temperature higher than the recrystallization temperature of the metal, and is applied to non-degreased sheet, i.e. sheet which is still coated with at least part of the rolling oil, and in that this heating is carried out, at least in its initial period, in a naked flame furnace, preferably of the incomplete combustion type, and in that the rapid cooling comprises a step in which the sheet is contacted with an aqueous medium, preferably at a temperature greater than 75° C.
It should be understood that, in the present specification, the expression "aqueous medium" does not only signify, in a limiting manner, a bath of water alone, but also covers any aqueous medium, saturated or not, containing matter in solution and/or in suspension for any required purpose. The aqueous medium may be provided in the form of a bath, jets of water, or mist sprays, separately or in combination, in any desired sequence.
The application of the method of the invention may, in addition, be adapted, according to requirements, to the various products to be treated.
Thus, in certain cases, the surprising effects of the treatment in a naked flame furnace of sheet which has not been degreased may be further improved. In respect, in particular, of its mechanical properties, the sheet may be subjected to a carbon precipitation phase at a temperature of between 200° C. and 500° C., following the rapid cooling.
In addition to this first improvement, which is itself considerable, of the surface quality of metal sheet, the method also comprises a further advantage.
It is known that during the heating of steel in an oxidising medium, certain elements contained in the steel, such as manganese, chromium, and phosphorus, which may be oxidised to a greater extent than iron, migrate towards the surface. This causes surface enrichment of the steel in certain elements, even if the steel only contains very low amounts of these elements. Thus, a mild steel containing 0.3% of manganese may, in an extreme case, have a surface content of manganese of approximately 15% after batch annealing, even if the annealing has been carried out under a protective atmosphere of N 2 /H 2 having a low dew point and a low O 2 content. The residual H 2 O and O 2 contents of the gas are sufficient to attract the manganese towards the surface, and the very long duration (several hours) and high temperature (700° C.) of the process enable the phenomenon to become very marked.
In principle, the case of continuous annealing, the dwell time at a high temperature is considerably shorter (a few minutes) and therefore the surface contamination by other elements rising from the mass of the sheet should be considerably lower. We have, however, noted that the reduction of surface enrichment may only be obtained in the absence of alkaline degreasing, as the latter causes the formation on the surface of a film of residual silica which provides an oxidising potential causing the segregation of the alloying elements contained in the body of the sheet.
BRIEF DESCRIPTION OF THE DRAWING
The accompanying drawing is a graph of the photoelectron spectra of the surface of two steels.
The graph demonstrates that steel which is continuously annealed after alkaline degreasing has a considerable surface enrichment in manganese, whilst the same steel continuously annealed in a naked flame furnace and without preliminary degreasing only shows a slight increase in Mn content.
This graph (in which the number of electrons --NCN-- is shown on the Y-axis and the bonding energy --eV-- is shown on the X-axis) gives the standardised photoelectron spectra (ESCA) detected on the extreme surface of two continuously annealed mild steels, i.e. after alkaline degreasing before annealing (steel A) and with degreasing carried out in the naked flame furnace according to the method of the invention (steel B).
One observes a surprising decrease in Mn enrichment. In effect, the sheet obtained with the method of the invention had a greater resistance to atmospheric corrosion and to rust pitting during storage. An improvement of this type is very important, bearing in mind the considerable number of sheets which are usually rejected on delivery to the client owing to corrosion pits.
A particular operational embodiment of the method of the invention provides a further improvement of the surface quality. This embodiment comprises treatment in an acid medium, carried out during or after cooling. A treatment of this type enables the quasi complete elimination of any trace of surface contamination, whether resulting from the residual carbon, the rolling oil, or the residual enrichment in elements which have risen from the body of the steel.
An operation of this type may be advantageously carried out after an oxidising phase of the annealing: quenching in an aqueous medium or exposure for a limited duration to an oxidising gas. The removal of the slight oxide film resulting from this step enables hitherto unequalled surface contamination levels to be obtained. The acid used may advantageously be an organic acid, preferably based on or consisting of formic acid. The acid treatment may be advantageously carried out after the rapid cooling or after final cooling.
The following example shows the result of a step of this type following a treatment which comprises immersion in an aqueous bath brought to boiling point. Table I shows that the surface of the steel, which was already very contaminated after quenching (and thus also before quenching as this was carried out in distilled water), was considerably improved by the pickling treatment used. In this example, the total amount of carbon (C tot ) on the extreme surface was ascertained using the method of the Ford test.
TABLE I______________________________________Sample C.sub.tot mg/m.sup.2 1 face______________________________________Continuous naked flame annealing+ quenching in boiling water 0.4Continuous naked flame annealing+ pickling and rinsing 0.2______________________________________
Table II shows the case of a steel subjected to exposure to air under cover for 48 hours in the summer. The first sample (A) was subjected to a treatment of a continuous nature comprising alkaline degreasing, heating to 700° C. in a conventional radiant tube furnace under N 2 /H 2 , holding for a minute at this temperature, air jet cooling to 500° C., slow cooling for 3 minutes from 500° C. to 400° C., and final atmospheric gas cooling to ambient temperature. The second sample (B) was subjected to a similar treatment, but in which the first cooling was replaced by quenching in water and reheating to 450° C.
The three other samples (C,D,E) were produced in accordance with the method of the invention: heating of the non-degreased sheet in a vertical naked-flame furnace (combustion being controlled in order to produce reducing fumes as a result of insufficient combustion air), rapid cooling, overaging treatment at 450° C. for 1 minute, and final cooling to ambient temperature. The rapid cooling was carried out in three different ways:
(a) jet cooling under atmospheric gas (sample C), causing very slight oxidation;
(b) water treatment (D), causing slight and irregular oxidation;
(c) immersion in an aqueous bath at a temperature approaching boiling (E), causing uniform oxidation to a thickness of 100 to 600 A.
The samples were then pickled by immersion in a bath of formic acid at a concentration of 1 g/liter for 5 seconds. The corrosion resistance, according to the above-mentioned test, was then evaluated on a scale of 0 (very high resistance) to 10 (flow resistance). The results obtained were as follows:
TABLE II______________________________________ Atmospheric corrosionSample evaluation after 48 hours______________________________________A 10B 8C* 6D* 3E* 1______________________________________ *In accordance with the method of the invention.
Thus one can see that the use of a naked flame furnace and the absence of degreasing produce an improvement in each case. This is further enhanced if the treatment includes an oxidising phase, particularly if the oxide produced is uniform and is 100 to 600 A thick.
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Metal sheet (cold-rolled steel sheet) contaminated with rolling oil is heated at a temperature higher than its recrystallization temperature in a naked flame furnace, e.g. of the incomplete combustion type. The heated sheet is then rapidly cooled by contact with an aqueous medium. The resulting sheet has considerably improved suitability for phosphate coating and painting, compared with sheet which is annealed after alkaline degreasing. The sheet is preferably treated with formic acid.
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BACKGROUND OF THE INVENTION
This invention relates to line trimmers for trimming vegetation, such as weeds and grass, and, more particularly, to line trimmers having a guard mounted thereon.
In the prior art, it is known to mount guards onto line trimmers (as used herein, a “line trimmer” is a hand-held, motorized device having a drive shaft with a rotating cutting head, wherein at least one filament is mounted to the cutting head that is caused to flail upon rotation of the cutting head and used to trim vegetation, such as weeds and grass (e.g., the line trimmer sold under the brand “WEED WHACKER”)).
It is also known to provide a cutting edge on the guards of line trimmers. The cutting edge is disposed in, and generally obliquely to, a plane defined by the flailing of the filament, and acts to clip excessive filament length. In this manner, the cutting edge ensures that the length of the filament does not exceed the size of the guard and, upon rotation, does not extend therebeyond. Examples of such cutting edges are shown in U.S. Pat. No. 4,550,499 to Ruzicka, and U.S. Pat. No. 6,052,976 to Cellini et al.
In U.S. Pat. No. 5,491,962 to Sutliff et al., a line trimmer is disclosed having both flexible filaments and rigid cutting blades mounted to the rotating head. The rigid cutting blades and the flexible filaments are disposed generally parallel with the flexible filaments being located above the cutting blades; the flexible filaments and the rigid cutting blades are vertically aligned. With two sets of rotating cutting elements in the Sutliff et al. device, vegetation is simultaneously double-cut upon engagement of the blades and filaments and, in effect, mulched.
It is an object of the subject invention to provide a line trimmer having a cutting member with at least one rigid knife edge disposed on a guard that is non-rotatably mounted onto the line trimmer.
It is also an object of the subject invention to provide a line trimmer having a cutting member with at least one rigid knife edge disposed on a guard, with the knife edge being spaced from a plane defined by the flailing of a filament upon rotation of the cutting head.
SUMMARY OF THE INVENTION
The aforementioned objects are met by a line trimmer having a guard mounted thereto, with a cutting member having at least one rigid knife edge being disposed on the guard. The line trimmer also includes at least one filament which flails upon rotation of the cutting head. The knife edge is spaced from any plane defined by the flailing filament(s). Advantageously, the knife edge cuts vegetation in concert with the filament(s). As a variation, the cutting member may include a second knife edge which is disposed to pass through the plane(s) defined by the flailing filament(s) so as to trim excess length of the filament(s). Accordingly, the filament(s) will not extend beyond the guard of the line trimmer while flailing.
These and other features will be better understood through a study of the following detailed description and accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a line trimmer in accordance with the subject invention;
FIG. 2 is a bottom plan view of a guard, cutting head and filament of the line trimmer; and,
FIG. 3 is a side elevational view of the guard, cutting head, and filament.
DETAILED DESCRIPTION OF THE INVENTION
With reference to FIG. 1, a line trimmer is shown and generally designated with the reference numeral 10 . The line trimmer 10 , as is typical in the art, includes a drive shaft 12 , to which is mounted a cutting head 14 , a motor 16 for causing rotation of the cutting head 14 , and a guard 18 . The design and configuration of the drive shaft 12 , the cutting head 14 and the motor 16 are well known in the prior art and any such design and configuration may be used herein.
With reference to FIGS. 2 and 3, the cutting head 14 is generally disc-shaped with at least one filament 20 being mounted thereto and extending therefrom. Although a single filament 20 is shown in the FIG. 2, multiple filaments may be used, as is customary in the prior art and shown representatively in dashed lines in FIG. 3 . The filament 20 is mounted to the cutting head 14 using any technique known in the prior art, such as being spool-mounted or threaded directly into the cutting head 14 .
Upon rotation of the cutting head 14 , the filament 20 is caused to flail. With the filament 20 flailing, a reference plane R is defined by the sweeping motion of the filament 20 . If multiple filaments 20 are used, each of the filaments 20 sweeps a reference plane R, the multiple reference planes R being coplanar, not coplanar, or a combination thereof.
The guard 18 is preferably non-rotatably mounted to the drive shaft 12 and is located in proximity to the cutting head 14 . The guard 18 radiates outwardly from the drive shaft 12 to at least sweep across an arc A. In particular, the guard 18 includes a top portion 22 , which radiates outwardly from the drive shaft 12 , and a skirt 24 which depends downwardly from the top portion 22 . The top portion 22 and the skirt 24 may be formed with various dimensions (i.e., the size of the arc A; the radius of the top portion 22 ; the height of the skirt 24 )—it must be noted that the guard 18 serves to protect a user from rocks, gravel, cut grass, and other debris which are hurled upwardly and/or outwardly from the cutting head 14 during use, so the extent of selected dimensions will dictate the amount of protection afforded by the guard 18 .
A cutting member 26 is mounted to the top portion 22 , and, preferably, the cutting member 26 is rigidly mounted to prevent movement thereof. As shown in FIG. 2, the cutting member 26 has a rigid knife edge 28 which extends beyond the top portion 22 . The knife edge 28 may be of any cutting edge design known in the prior art which serves to cut vegetation in addition to the filament 20 as described below (e.g. a tapered edge; a dihedral edge). Preferably, the knife edge 28 (and the cutting member 26 ) are metallic, e.g., steel.
The knife edge 28 is located to oppose the movement of the filament 20 . In addition, as shown in FIG. 3, the knife edge 28 is located to be spaced from the reference planes R, and, preferably is disposed to be generally parallel to at least one of the reference plane(s) R. If multiple filaments are mounted to the cutting head 14 , the knife edge 28 is spaced from all of the reference planes R. As a result of this configuration, the flailing filament 20 strikes vegetation against the knife edge 28 resulting in the vegetation being cut both by the filament 20 and the knife edge 28 ; the knife edge 28 acts to second-cut vegetation in a mulching effect. If multiple filaments are used, the vegetation is further cut into smaller parts further enhancing the mulching effect.
The cutting member 26 can be mounted to the guard 18 using any technique known to those skilled in the art. Preferably, the cutting member 26 is mounted to a lower surface 29 of the top portion 22 of the guard 18 . Also, the cutting member 26 is formed with a rearwardly-extending moment arm 30 which extends generally in the same direction as the rotation of the cutting head 14 . More preferably, the moment arm 30 is formed to be located in proximity to the cutting head 14 . By extending in the same direction as the rotation of the cutting head 14 , the moment arm 30 counteracts force imparted thereto by the filament 20 (via impacted vegetation). In addition, the largest imparted force is located closest to the cutting head 14 , thus, requiring the most-significant counteraction in proximity thereto.
In a preferred arrangement, the knife edge 28 extends beyond an edge 32 which defines one limit of the arc A of the guard 18 . It is also preferred that the knife edge 28 be generally parallel to the edge 32 and be at least coextensive therewith.
As an additional variation, the cutting member 26 may be unitarily formed with a second knife edge 34 (preferably, metallic (e.g., steel)) that is disposed inside of the skirt 24 and passes through at least one of the reference planes R. As shown in FIG. 3, the knife edge 28 and the second knife edge 34 may define a L-shape with the cutting member 26 being formed from a unitary piece of metal. The second knife edge 34 is positioned to trim excess length of the filament(s) 20 . In this manner, no filament 20 will flail into, or beyond, the guard 18 .
As is readily apparent, numerous modifications and changes may readily occur to those skilled in the art, and hence it is not desired to limit the invention to the exact construction and operation as shown and described, and, accordingly, all suitable modification equivalents may be resorted to falling within the scope of the invention as claimed.
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A cutting member is provided for mounting onto a guard for a line trimmer, the cutting member having at least one knife edge for cutting vegetation in concert with the flailing filament(s) of the trimmer. The knife edge is spaced from any planes swept by the flailing filaments. Additionally, the cutting member may be provided with a second knife edge that is positioned to trim excess length of the filament(s), thus ensuring no filament extends beyond the guard while in use.
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This invention relates to an improved method for the preparation of 1,1'-methanebis(hydantoin), hereinafter MBH, a compound having the following formula: ##STR1## MBH is an intermediate in a method of the preparation of N-(phosphonomethyl)glycine (PMG), which is disclosed in U.S. Pat. No. 4,578,224. The compound N-(phosphonomethyl)glycine is a well known herbicide and plant growth regulator.
BACKGROUND OF THE INVENTION
U.S. Pat. No. 2,418,000 discloses the preparation of MBH from hydantoin and a formaldehyde source including paraformaldehyde, anhydrous formaldehyde gas or 37% formaldehyde solution in the presence of HCl and water, wherein the concentration of water is between 13-30 weight percent of the reaction mixture. The preferred concentration of water is between 18-27 weight percent. The specification of U.S. Pat. No. 2,418,000 specifically states that if the water content of the reaction mixture is greater than 30 weight percent, the desired product is produced in very low yields. Although the preferred embodiment of that procedure is reported to give MBH in 87% yield, the amount of solvent used is so small, and MBH is so insoluble that the reaction mixture solidifies upon completion of the reaction. A solidified product in the reaction vessel is undesirable because of the increased handling procedures required to remove and/or transfer the product.
Due to the importance of N-(phosphonomethyl)glycine, new and alternative methods of preparation of this beneficial herbicide are continually being explored. In addition, newly improved methods of preparation are also desirable.
It is an object of the present invention to provide an improved method for the preparation of MBH. It is a further object of this invention to reduce the cost of producing PMG by increasing the reaction yield of MBH. A still further object of this invention is to include in the reaction medium a sufficient amount of water to produce a stirrable reaction mixture, thereby increasing ease of product handling
SUMMARY OF THE INVENTION
It has now been surprisingly found that an increase in the initial weight percent of water in the reaction mixture of hydantoin and the formaldehyde source to generate MBH is beneficial to the percent yield of the product. It has now been found that the reaction can be carried out in 95-97% yield with an initial water content of the reaction mixture equal to 35-90% weight percent and stoichiometric amounts of reactants. This water content represents at least a two-fold increase of what was previously regarded as the preferred amount.
This invention may be summarized as a method for the synthesis of 1,1'-methanebis(hydantoin) comprising: contacting hydantoin with a formaldehyde source in an aqueous medium containing about 35-90% water and a strong protic acid.
DETAILED DESCRIPTION OF THE INVENTION
The starting compounds for this process arc; hydantoin, a formaldehyde source, a protic acid and water. The reaction may be schematically represented as follows: ##STR2## wherein CH 2 O represents a formaldehyde source described in detail below and HX is a protic acid.
Hydantoin is present in the reaction mixture in approximately stoichiometric amount compared to the formaldehyde source. Thus, the preferred amount is a 2:1 molar ratio of hydantoin to the formaldehyde source.
As shown in the examples below, paraformaldehyde or about a 37% formaldehyde solution may be used interchangeably as the formaldehyde source. In addition, the formaldehyde source may be anhydrous formaldehyde gas or a formaldehyde alcohol complex. The formaldehyde alcohol complex is described in detail in U.S. Pat. No. 5,399,759.
The formaldehyde alcohol complex is a means for providing a formaldehyde reactant to a chemical process by contacting paraformaldehyde with about 0.25 to about 3 mole equivalent of an aliphatic alcohol, in the presence of a catalytic amount of a base, and then providing the product to the process.
The preferred formaldehyde source is paraformaldehyde or about a 37% formaldehyde solution.
The preferred acid used in this process is concentrated hydrochloric acid; however, other strong protic acids are suitable. Other suitable acids include hydrobromic, hydroiodic, sulfuric, and phosphoric acids. These acids may be regarded as strong protic acids. The concentration of the protic acid should be about 3-6 mole equivalents of acid per mole equivalent of formaldehyde source.
The reaction may proceed by first adding hydantoin, followed by the formaldehyde source, and while stirring, adding concentrated hydrochloric acid. However, the exact sequence of reactant addition is not important. The total water content of the initial reaction mixture is about 35-90 weight %, the preferred amount is about 35-75 weight % and the most preferred amount is about 35-50 weight %. At the end of the reaction period water is added, the reaction mixture is filtered and the MBH product is dried.
The following examples serve to illustrate this invention:
EXAMPLE 1
To a nitrogen purged three-neck round bottom flask equipped with overhead stirrer, water condenser and nitrogen line were added 10.11 grams (100 mmol) of 99% hydantoin and 1.58 grams (50 mmol) of 95% paraformaldehyde. While the mixture was stirred, 14 mL of concentrated HCl was added. The mixture was stirred at room temperature overnight. The initial water content in this reaction mixture was 37 % by weight.
After about 20 hours, 15 mL of water was added to the mixture, and the reaction mixture was filtered through a fritted glass funnel. The resulting white cake was washed with water and dried overnight in a vacuum oven to afford 10.26 g of 1,1'-methane-bis(hydantoin) as a snow white powder. The identity of the product was confirmed by mass spectrometry, 1 H NMR and 13 C NMR. The purity of the product was determined to be 99% by quantitative 1 H NMR spectroscopy using 99.7% 1,4-dichlorobenzene as an internal standard. Hence, the corrected yield of MBH was 95%.
EXAMPLE 2
To a nitrogen purged three-neck round bottom flask equipped with overhead stirrer, water condenser and nitrogen line were added 10.11 grams (100 mmol) of 99% hydantoin and 1.58 grams (50 mmol) of 95% paraformaldehyde. While the mixture was stirred, 21 mL of concentrated HCl was added. The mixture was stirred at room temperature overnight. The initial water content in this reaction mixture was 42 % by weight.
After about 26 hours, 21 mL of water was added to the mixture and the reaction mixture was filtered through a fritted glass funnel. The resulting white cake was washed with water and dried overnight in a vacuum oven to afford 10.24 g of 1,1'-methane-bis(hydantoin) as a snow white powder. The identity of the product was confirmed by mass spectrometry, 1 H MR and 13 C NMR. The purity of the product was determined to be 100% by quantitative 1 H MR spectroscopy using 99.7% 1,4-dichlorobenzene as an internal standard. Hence, the corrected yield of MBH was 97%.
EXAMPLE 3
To a nitrogen purged three-neck round bottom flask equipped with overhead stirrer, water condenser and nitrogen line were added 10.11 grams (100 mmol) of 99% hydantoin and 3.8 mL (4.1 g) of 36% formaldehyde in water (50 mool). A pipette was used to add the formaldehyde solution to the reaction flask. While the mixture was stirred, 14 mL of concentrated HCl was added. The mixture was stirred at room temperature overnight. The initial water content in this reaction mixture was 42% by weight.
After about 18 hours, 14 mL of water was then added to the mixture and the reaction mixture was filtered through a flitted glass funnel. The resulting white cake was washed with water and dried overnight in a vacuum oven to afford 10.43 g of 1,1'-methanebis(hydantoin) as a snow white powder. The identity of the product was confirmed by mass spectrometry, 1 H NMR and 13 C NMR. The purity of the product was determined to be 99% by quantitative 1 H NMR spectroscopy using 99.7% 1,4-diichlorobenzene as an internal standard. Hence, the corrected yield of MBH was 97%.
EXAMPLE 4
To a nitrogen purged three-neck round bottom flask equipped with overhead stirrer, water condenser and nitrogen line were added 10.11 grams (100 mmol) of 99% hydantoin and 3.8 mL (4.1 g) of 36% formaldehyde in water (50 retool). A pipette was used to add the formaldehyde solution to the reaction flask. While the mixture stirred 21 mL of concentrated HCl was added. The mixture was stirred at room temperature overnight. The initial water content in this reaction mixture was 47% by weight.
After about 18 hours passed, 21 mL of water was then added to the mixture and the reaction mixture was filtered through a flitted glass funnel. The resulting white cake was washed with water and dried overnight in a vacuum oven to afford 10.26 g of 1,1'-methanebis(hydantoin) as a snow white powder. The identity of the product was confirmed by mass spectrometry, 1 H NMR and 13 C NMR. The purity of the product was determined to be 100% by quantitative 1 H NMR spectroscopy using 99.7% 1,4-dichlorobenzene as an internal standard. Hence, the corrected yield of MBH was 97%.
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This invention relates to method for the preparation of 1,1'-methane-bis(hydantoin). 1,1'-methane-bis(hydantoin) is an intermediate in the preparation of N-(phosphonomethyl)glycine which is a well known herbicide and plant growth regulator.
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BACKGROUND OF THE INVENTION
The present invention relates to a heating system control device and in particular to an electronic control device which is programmable by the user.
While heating system control devices are known in the art, such conventional devices have very little flexibility and thus offer little adjustment of the control of a heating system. The ability to adjust various parameters in the heating system has taken on new importance with the considerable increase in heating fuel costs.
In conventional control devices, the heating cycle time was controlled by a heating cycle motor and a change in the heating cycle necessitated a change in the motor itself. Moreover, conventional devices had difficulty in accommodating the 24 hour clock thereof to a seven day clock without substantial changes in circuitry.
Further, standard off-the-shelf systems were not adaptable to different buildings and thus each device would have to be fitted with customized parts such as motors for particular applications.
Other disadvantages of the conventional systems were that they could not reduce the duty cycle of the heating cycle below certain mechanical limits defined by the elements used therein and thus the systems would generate too much heat in the spring and in the fall.
Furthermore, with the desire to save as much money as possible with heating and thus keeping buildings cold at night, conventional systems had difficulty in adapting to the initial warm-up period in the morning and thus buildings remain cold even during the early morning working hours.
SUMMARY OF THE INVENTION
The main object of the present invention is to provide a heating system control device which is capable of being adaptable to any heating requirements of a building without the addition of new circuitry or different circuitry and which is easy to operate and which overcomes the disadvantages of the prior art devices as set forth hereinabove.
Another object of the present invention is to provide a heating system control device which allows for a morning boost in the heating system to enable the heating system to be at a low temperature during the evening hours but still adequately warm the building in the early morning for the start of working hours.
Another object of the present invention is to provide a thermal lock-out which ensures that no heat will be supplied to the building regardless of the outdoor temperature in order to save on heating.
Another object of the present invention is to provide a completely solid state device which operates automatically to control a heating system.
These and other objects of the present invention are provided by the heating system control device according to the present invention which includes means responsive to the dropping of the outside temperature to below a predetermined weatherhead set point for turning on a heating system, means for determining the establishment of heat in a heating system, means defining a heating cycle consisting of a heat on portion and a heat on portion having a duty cycle dependent on the outside temperature and starting in response to the establishment of heat in the heating system and means for checking for heat loss in the system under control and for delaying the start-up of new heating cycle when heat is established until more heat is needed.
In accordance with the present invention, the heating control device has a microprocessor heating control circuit which is designed to control a building's heating system effectively and economically producing a smooth flow of heat when and where it is needed and to the degree it is desired.
The device is capable of reducing temperature levels when not needed and by eliminating high peaks of uncontrollable surges and heat to effect substantial energy savings. The device can be programmed for carrying out complex computations automatically and the controls for the device are simple switches and knobs and the display elements therefor include a digital display and function lights.
These and other objects and advantages of the present invention will become clear from the detailed description of the present invention and in accordance with the drawings wherein:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic representation of the heating control device and its connection to a heating system in accordance with the invention;
FIG. 2 is a front view of the control panel for the device according to the invention;
FIG. 3 is a timing diagram showing the operational timing of the heating system controlled in accordance with the present invention;
FIG. 4 is a block diagram of the circuit of the device according to the present invention;
FIG. 5 is a detailed schematic circuitry for the sensor inputs and control settings of FIG. 4; and
FIG. 6 is a detail of the circuitry for the control panel switch inputs of FIG. 4.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a schematic of the connection of the heating control device 1 of the present invention to a heating system which includes a building B, a heating plant P within building B and a sensor S1 for sensing the outside weatherhead temperature and a sensor S2 for sensing the indoor heating temperature. The control device directly feeds to the heating plant P to control same as will be explained hereinafter.
The device 1 continuously monitors the outside temperature by means of sensor S1 and at the same time monitors the heat loss of the building by means of the inside temperature sensor S2 located on a return line of the heating system inside the building. On the basis of the combined information, the device 1 sends instructions to the heating plant P as will be explained.
The control of the heating plant P is basically by turning the heating plant on and off. The device tells the heating plant by means of an electrical signal when to go on and how long to stay on and when to go off and how long to stay off. Basically, the device controls the heating plant in accordance with heating cycles, by controlling the duty cycle of each cycle, the frequency of the cycle and the delay between cycles.
A cycle is a set time period, such as 60 minutes, and consists of a heat-on part followed by a heat-off part, both parts always adding up to exactly the predetermined set time period (i.e. 60 minutes).
The length (or duty cycle) of the on part when heat is produced, is controlled by means which varies this length in dependence on a number of factors. For example, the lower the outside temperature, the longer the on part in relation to the off part. The ratio between the two is also controlled by the selection of weatherhead set points compared to the outside temperature sensed by sensor S1.
Another factor that is sensed by the device according to the present invention is the heat loss of the heating plant P. The heat loss which is measured by inside heating sensor S2, determines whether cycles will follow each other without delay or with some delay. The device automatically monitors the heat loss in the building as reflected by the return pipe temperature to see if heat is still established at the end of the cycle. The so-called establishment of heat in the system is defined as a predetermined return pipe temperature which shows that heat has spread through the entire radiation system of the building.
If heat is still established at the end of the cycle, the device reacts to this by effecting a delay between successive cycles thus delaying the next on time for the heating plant.
The device also has the capability of establishing two general system heating levels, one defined as normal which is traditionally set during the daytime and is relatively higher and the other defined as a saving level which is traditionally set at nighttime and is a lower heating level that saves energy when a building is vacant or the people therewithin are usually asleep.
The device according to the present invention controls the building heating system, as shown in FIG. 3, by first turning on the heating plant P at time T0 to effect an establishment of heat. When the sensor S2 indicates that heat is established within the building B, time T1 is reached wherein the normal heating cycle, for example 60 minutes is established with the duty cycle thereof determined by the outside temperature sensed by sensor S1. When the heating cycle terminates at time T3, if heat is still established within the building as indicated by sensor S2 and if the sensor S2 shows that heat is not needed yet, a thermal lock-out will be effected wherein the next heating cycle is delayed until time T4 when sensor S2 indicates that heat is needed. At this point, the normal heating cycle will again begin.
The system control circuitry for carrying out the above is shown in more detail with respect to FIGS. 2 and 4-6 as will be explained hereinafter.
With regard to FIG. 2, the control of the functions of the device will be explained as will the operation of the device in accordance with the invention.
The front panel of the device according to the present invention includes a plurality of switches and display elements for programming the device to automatically carry out heating plant control instructions day after day and for 24 hours every day.
The display panel 2 includes heat adjustment controls 40 for raising or lowering the buildings general heat level. Included in this control is knob 41 which sets the normal or conventionally daytime heat level setting and knob 42 which sets the save or conventionally nighttime heat level. These knobs control potentiometers 43 and 44 respectively shown in FIG. 5 and which constitute two of the output signals of the circuit block 180 shown in FIG. 4.
The two heat levels are set on an alphabetical scale from A-P with the lowest point being A and the highest point being P. For each adjustment upward on the heat on part of the cycle, there is a slight increase in the duration of the duty cycle. This adjustment affects a fine tuning of the heating cycle since other factors also influence the heat levels. The setting of knobs 41 and 42 is determined primarily by the heat loss characteristics of the building.
The weatherhead set points for both the normal and save periods for a given day are set in section 20 of the control panel including thumb switches 21 and 22 which set the weather head set point temperatures for the normal and save conditions respectively.
If as shown the normal weather head set point is set for 50° and the save set point is set for 42°, the heating system will not go on unless the outside temperature is at or below 50° during the normal periods during the day and at or below 42° when during the save periods. The status of the system is indicated by lights 24 and 25 which indicate that the normal or save periods respectively are in effect at any given time. The control lights 24 and 25 are included in the control lights and relay block 152 in FIG. 4.
The system also has the ability to manually shift from the save period level to the normal period level by use of the shift push button 23. In response to the actuation of push button 23, the device will shift from the save to the normal level for a given period of time (i.e. 90 minutes) and then revert back to the save period if the program calls for the save temperature level at that time.
Section 30 of the control panel includes the auto by-pass push button 31 and the key switch 32 for enabling the device to be programmed as will be explained hereinafter. The by-pass push button 31 enables the entire device to be by-passed so that the heating system is in the constant on condition. The program lock switch 32 merely prevents the device programming to be changed when in the locked position as will be explained hereinafter.
The device operates with two heat levels, the higher heat level normally scheduled for when people are up and about, is called the normal level and the lower one called the save level is for when people are asleep or the building is unoccupied. The two heat levels can be changed alternately from one to the other up to 8 times a day as programmed into the device and each of the seven days of the week can be programmed differently as will be explained.
The programming of the period times is set in sections 50 and 60 of the control panel 2. In section 60, switches 61-67 control the programming of the device as is indicated by the display in secton 50 including display elements 51-54.
Switch 67, when pushed from the run to the program position, changes the display section 50 from a display of the current time/temperature to the programmed data. The program mode is effected by the opening of key switch 32 and switch 67 at run and then the minute switch is depressed and the display will cycle from 1 through 59 until the button is released. Thereafter the hour display button 64 is depressed to set the particular hour desired for the day set in the display. The display 51 first displays the first normal period to be set and then the first save period to be set. If more than one normal period is to be utilized in a 24 hour day, the pressing of the advance button 66 will advance the display to be programmed into the second normal and second save periods. The pressing of the erase button 65 will erase the current pair of normal and save settings.
After the day has been completed, the day button 62 is depressed and it switches to the next day. If one desires to have the same timing for each day, the day copy button 61 can be pressed which merely copies the program from the previous day into the day now displayed. The clock is programmed for the entire week in this manner. At the end of the program, the switch 67 remains in the run position and the key switch 32 is placed in the locked position.
Light 51 indicates the day of the week in the display section 50 and light 54 illustrates whether the time being displayed on section 52 is AM or PM. Display 53 illustrates the outside temperature when the unit is in the run state as indicated by switch 67.
The display also includes section 10 including lights 11-13 which indicate the status of the heating plant. When light 11 is on, this means that the heat plant is on and the heat is being established therein. When lights 11-13 are all on, this means that heat is established and the cycle is in the on phase. When the lamps 12 and 13 are on, this means that the system is in the off phase of the cycle. When the lamp 13 is on alone, this is the off phase of the cycle and the heat is no longer established. When only light 12 is on, this means that the system is in the thermal lock-out phase.
Another function of the control device according to the invention is the addition of the morning boost control knob 91 which controls potentiometer 92 shown in FIG. 5 for establishing a so-called morning boost.
The morning boost control is an early morning surge of heat needed to overcome low nighttime temperatures. By setting knob 91 to the desired morning boost time of from 0 to 120 minutes, the heating plant will be turned on for the morning boost time set by knob 91 during the first normal cycle during a given 24 hour day. Thus if the morning boost knob 91 is set for 90 minutes, the heat will go on for the full 90 minutes regardless of the establishment of heat and the cycle time set for the heating cycle. This morning boost will start at the first normal heat level period of the day. Light 98 indicates that the control device is in the morning boost mode.
Another feature of the morning boost control is an automatic boost wherein, utilizing the circuitry shown in FIG. 5 and indicated as 91' and by setting knob 91", the morning boost will be completely automatic in adjusting its time span each day to the outside temperature without any operator attention.
The variable boost works in a way which is similar to the manual version, except that it is not preset to a specific time period. It times its duration each day based on the outside temperature and it does this automatically, the higher the outside temperature, the shorter the morning boost.
It also times the morning boost to start far enough in advance so that heat is established at whatever time the operator sets the first day setting on the clock.
For example, if heat is to be established at 7:00 AM, the device will interrogate the weatherhead for the outside temperature three hours in advance, which in this case would be 4:00 AM and automatically calculates on the basis of the outside temperature, at which time the heat source must go on to reach an established temperature by 7:00 AM.
Although the automatic morning boost is self sufficient in operation, there is a one time adjustment to make at the outset on potentiometer 91" to compensate for the specific characteristics of the buildings heating system. A module containing the circuitry 91' and 91" makes it possible to achieve an infinite number of variable settings, which based upon experience for a particular building, will enable one to choose the best setting for the building. Once the optimum setting is found, it can be left there and the entire process will hence forth be automatic.
The automatic variable boost circuitry can also be used to effect an automatic early shutdown of the heating system. Utilizing the same circuitry, the device can automatically shutdown the heating system in advance of the last night-time heat level so that the heating system can "coast" to its night-time level. For example, if the low night-time heat level is scheduled to start at 11:00 PM, the automatic shut-down will turn off the system at an earlier time depending upon the outside temperature. Thus the heating system may turn off at 10:00 PM in anticipation of the fact that the low night-time heat level begins at 11:00 PM and the outside temperature is at a particular level which warrants such an anticipated shut-down.
Control section 80 includes switches and settings for adapting the control device to the buildings heat loss.
The slide switch 83 provides a choice of four cycle times, 20, 30, 60 or 90 minutes. The optimum cycle time for a building is determined by the kind of heating system and the type of radiation. Where the radiation system looses heat fast, a shorter cycle time is called for, while the system whose radiation holds heat longer, calls for a longer cycle time.
The set point for the return pipe sensor S2 is determined by control knob 95 which controls potentiometer 96 as shown in FIG. 5. Since the sensor S2 at the return pipe inside the building B is positioned where steam and water return to the boiler after moving through the buildings heating system, it reflects the heat loss of the building. It also determines when heat is considered established in the building that is when heat has permeated the entire building.
Since there are so many variables involved in establishing heat circulation in the building, the set point for the sensor is best fixed by trial and error.
The system sensors set point is set by allowing the radiation in the building to be near room temperature, setting the knob 95 to position Z, turning the heating system on, waiting for radiation at the farthest point from the boiler along the return pipe to become warm and then slowly turing the knob 95 until status light 12 goes on. This is the optimum setting for establishing heat in the building.
The thermal lock-out or delay between cycles is controlled by switches 83 and 84 as will be explained. At the end of a cycle, a new one starts at once if heat is still established. However, if there is heat already in the building it is not necessary to start a new cycle immediately since this acts to merely waste heat. The thermal lock-out switch 84 when positioned in the off cycle operates the device in a normal continuous cycle mode. When placed in the on position, the device will automatically prevent the new cycle from starting if heat is still established in the building and is above the set point. When the return pipe cools to the set point, only then can a new cycle begin.
Control knob 93 which controls potentiometer 94 shown in FIG. 5, provides an electronic differential to further adjust the onset of new cycles in the thermal lock-out mode. The knob 93 adjusts the device so that the new cycle will be delayed until the return pipe temperature reaches as much as 50° below the set point. For example if the return pipe sensor is set at 180° F. and the differential is set at -25°, the new cycle will not start until the sensor at the return pipe drops to 155° F. This mode is most useful where the return pipe temperature at the heating system sensor S2 drops faster than the radiation temperatures in the building.
Other advantageous features of the device according to the present invention will now be explained.
In order to find out the actual temperature of the heating system, if one presses the button 81 the output of sensor S2 will appear in display 53 instead of the outside temperature from sensor S1. Since the display 54 is only capable of displaying two digits, the displayed inside temperature is shown divided by 3.
This display is particularly useful when the system is in the process of being established, since one can see the exact temperature at which the sensor establishes heat during operation.
Switch 82 is provided for effecting a fast cycle that changes the minutes of the electronic clock into seconds to that the cycle can be reviewed swiftly. A 60 minute cycle can be reviewed in 60 seconds on the display. By depressing the button 82, continuously, the display will show in one minute the exact duration of the heat-on and heat-off segments of the cycle for a 60 minute cycle. This information can be used to calibrate the device for a particular weatherhead set point to see if the device is operating properly.
The switch 85 simply turns off the control for a non-heating season. When the cold weather ends the switch is put on the off position and while in the off position the control will continue to display the outside temperature and the current time, although the heating plant will not be turned on.
The device according to the invention also includes the terminal strip 97 which has the inputs TT for the sensor S1 and inputs CC for sensor S2. The inputs CS-CS are for reverse polarity sensors. Terminal strip 99 is an output terminal for providing power for optional items. Along with terminal 99 are relays 88 and 89 for optional controls.
Referring now to FIGS. 4-6, the circuitry for effecting the functions set forth hereinabove are disclosed in more detail.
The device is powered by a main power supply 171 which receives a line voltage from an AC source. The output of the main power supply 171 is fed to a power sensor 172 which feeds microprocessor 100, clock generator 174 and all of the other circuitry included in the device. The power sensor senses if the power supply 171 is operational, and if not, it cuts in auxiliary battery power supply 173 so that the circuitry does not go down during the loss of the AC supply. The clock generator 174 generates the clock signals necessary to operate the system according to its specification. Also included is a program interrupt 175 which enables the system to be interrupted during use for servicing and the like.
The main control network of the device according to the present invention is the microprocessor 100 connected in a conventional configuration with an 8-bit bus driver 115 and in communication with a 16-bit latch address network 115 a ROM 120 and 3 RAM memories 125, 130 and 135 connected as shown. The microprocessor 100 feeds three control bits to decoder 110 which, on the basis of these bits, outputs 5 interrogation signals TB, SW, SWOPT, Day Thumb and Night Thumb, as shown in FIG. 5 to interrogate the status of the control panel switch inputs heretofore described. The decoder also generates five strobe signals strobe 1-5 which are used to direct the storage of data from the bus drive 105 to latches 140, 145, 150, 155 and 160.
The data on the bus which is controlled by microprocessor 100 is displayed as follows:
The 8-bit segment latch 140 received data from the data bus and upon the strobing by strobe 1, the data is stored in the latch 140. The digit data is supplied via the bus drive 105 to 8-bit digit latch 145 which data is entered therein by strobe 2. Upon the strobing of data into latches 140 and 145, the segment and digit drives 141 and 146 feed display 52, 53 to display the data therein.
The other control lights and relays are displayed and controlled via the 8-bit control latch 150 whose data is strobed in by strobe 3 and driven by control drive 151 so as to be indicated by the control lights and relays 152.
The determination of the levels and control settings shown in FIG. 5 and illustrated in FIG. 4 as block 180, are analyzed by the microprocessor by means of the analog multiplex latch 160 which stores 3 bits of data to select one of eight inputs on analog multiplexor 165 which is fed by the sensor inputs and control settings 180. Multiplexor 165 selects one of eight signals and inputs it to comparator 170. The microprocessor then determines the level of the data by incrementing the 8-bit ladder latch 155 via strobe 4 and driving the output thereof through drive 156 to a ladder network 157. The ladder network 157 generates a stepwise ladder which is fed into the comparator and which is fed back to the microprocessor when a favorable comparison is made thus indicating to the comparator that the data in the 8-bit ladder latch 155 is equal to the sensor input or control setting then under construction. The circuitry shown in FIG. 5 is conventional and provides for a processing of the sensor signals for use by the analog multiplexor.
FIG. 6 shows the block 190 which receives the interrogation outputs from decoder 110 which feeds the status of the switches and control panel settings to the bus drive for processing by the microprocessor 100.
In a particularly advantageous embodiment, the microprocessor 100 is an RCA 1802 microprocessor and the bus drive 105 comprises a TI 374 latch drive units. The latch 115 for the address is a TI 374 latch as are latches 140, 145, 150, 155 and 160. The ROM 120 is an AMI 9332 while RAM 125 is an RCA 1824 and RAMS 130 and 135 are AMI 5101 circuits.
The segment drive 141 is a Sprague 2800 as is control drive 151, while the digit drive 146 is a Sprague 2480. The ladder drive 156 is an RCA CD 4050 and the analog multiplexor 165 is an RCA 4051. The analog multiplex latch 160 is a 174 and the decoder 110 is a TI 7442. The comparator is a conventional operational amplifier in the most advantageous embodiment.
The device also includes stoking means for turning on the heating system to be controlled for a predetermined time each day regardless of outside temperature. It incluudes the stoke input shown in FIG. 6 in conjunction with the microprocessor instructions labeled "stoke" in the foregoing microprocessor program.
The microprocessor program for carrying out the aforementioned functions is set forth in the following printout listing thereof and it will be immediately recognizable by those skilled in the art that the entire operation of the device as set forth above can be achieved as a result of this step-by-step execution. ##SPC1## ##SPC2## ##SPC3## ##SPC4## ##SPC5##
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A heating system control device is responsive to the drop in outside temperature to below a predetermined weatherhead set point for turning on a heating system to be controlled. Upon the establishment of the heat in the heating system, a defined heating cycle is carried out consisting of a heat-on portion and a heat-off portion having a duty cycle dependent on the outside temperature. The heating cycle does not start until there is an establishment of heat in the heating system. The start of consecutive heating cycles is delayed in response to a check for heat loss in the system. When heat is established and the set point has not been reached, as noted by the means for determining the establishment of heat in the heating system, the next cycle will be delayed to save energy.
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The instant disclosure claims the filing-date benefit of U.S. Provisional Application No. 60/819,011, filed Jul. 7, 2006, the specification of which is incorporated herein in its entirety.
The disclosure generally relates to a modular frame and a covering therefor. In an embodiment of the disclosure, the modular frame is a free-standing structure which can be positioned independently or it can be combined with other similar structures to provide a larger span of coverage.
BACKGROUND
Conventional frame tents, party tents, vestibule tents and common rental tents are readily assembled and disassembled frame structures which incorporate conventional slip fit elements for legs, perimeter and roof support pieces. Supporting legs of conventional tents are spaced at increments of 10 to 20 feet, around the perimeter, along with the related gable, hip or pyramid components needed to support the tent top. These multi-component assemblies provide the structural elements for supporting the fabric tops of these shelters.
Frame tents are normally restricted to an interior span of less than fifty feet wide due to structural requirements. This is because the large span roofs require additional support and cannot be free-standing. Accordingly, tents larger than 50 feet are classified as pole, bail ring tents, clear span beam or truss structures. Conventional large tents require either a center pole (for supporting the roof fabric), a special extrusion material (to be used as a clear-span beam supporting the roof fabric), or multiple structural pieces (for forming a clear-span truss supporting the roof fabric). The multiple structural pieces form the base for tensioning the fabric top between the structural elements.
Pole or bale ring tents require many perimeter support legs, commonly spaced between 5 feet to 15 feet for tensioning the top; while clear span beams or trusses units require multiple purlin spacers to maintain alignment and structural integrity of the support frame and commonly are spaced at varying distances up to 20 feet. The roofs of such tents normally extent above the perimeter frame a distance equal to 25 percent of the width of the tent for frame and pole tents, while structures may extend 25 percent, or more, of the width of the tent from the ground. A standard 20 foot by 20 foot frame tent may have as many as 59 structural elements plus the top; while the quantity of pieces required to setup larger tents increases in both quantity and length of pipes or extruded beams.
The conventional large tent structures also have a roof member which directly supports the center or a portion of the roof. The roof member has been an essential part of the conventional tent structures especially when the tent's size increases requiring larger roof-top material. The roof members are typically positioned inside the tent thereby interrupting the space under the roof of the tent.
The conventional large tents are also heavy, inefficient and costly to produce and maintain. Because of the many structural parts, they provide difficult and time-consuming assembly and disassembly. Moreover, the weight of the fabric-top limits the span of the tent. Accordingly, there is a need for a free-standing structural system that addresses these deficiencies.
SUMMARY OF THE DISCLOSURE
In one embodiment, the disclosure relates to a free-standing structure which includes an eight-sided roof perimeter; at least four geodesic structures extending from four sides of the eight-sided roof perimeter and supporting the perimeter; and at least four legs, each leg structurally corresponding with one of the at least four geodesic structures for upholding the free-standing structure.
In another embodiment, the disclosure relates to a modular free-standing structure comprising: a plurality of support members forming a roof support structure and defining a roof perimeter for the free-standing structure; a roof fabric covering the roof support structure; a plurality of load transfer structures upholding certain of the support members and transferring the weight of the roof support structure; a plurality of legs for receiving the weight of the roof support structure and upholding the free-standing structure, the plurality of legs defining a footprint perimeter for the free-standing structure; wherein the footprint perimeter is larger than the roof perimeter.
In still another embodiment, the disclosure relates to a free standing modular structure comprising a plurality of support members forming an eight-sided perimeter for receiving a roof cover; a plurality of geodesic structures, each geodesic structure sharing at least one support member with the eight-sided perimeter to define a geodesic area for receiving a geodesic cover; and a plurality of legs, each leg structurally corresponding with one of the plurality of geodesic structures, the plurality of legs defining a footprint area for the modular structure; wherein the footprint area is substantially equal to a sum of a roof cover area and the geodesic areas.
In still another embodiment, the disclosure relates to a method for providing a free-standing coverage for an obstruction-free area, the method comprising providing a support perimeter for receiving a roof cover; providing a plurality of geodesic corner structures to extend from the support perimeter and to receive a geodesic cover; and freestanding the roof cover by connecting each of the geodesic corner structures to a leg member.
BRIEF DESCRIPTION OF THE DRAWINGS
The embodiment of the disclosure will be discussed in referenced to the following non-limiting and exemplary drawings in which:
FIG. 1 is a plan view of a modular frame according to one embodiment of the disclosure;
FIG. 2 is a schematic representation of an exemplary modular frame having the roof fabric assembled to the top of the frame pipe;
FIG. 3 is a side view of a portion of the modular structure shown in FIG. 1 ;
FIG. 4 is a plan view of an embodiment of the disclosure having parabolic shaped top where the fabric top is attached to the bottom of the frame pipe;
FIG. 5 shows a joint for connecting two members;
FIG. 6 shows a three-way joint for connecting three members;
FIG. 7 represents a three-way joint which has different angles for connecting three members;
FIG. 8 shows an exemplary base plate adapted to receive two legs;
FIG. 9 shows an modular frame adapted to combine with similar frames to form a larger structure;
FIG. 10 shows the modular frame of FIG. 9 with a parabolic shaped roof cover assembled thereon;
FIG. 11 shows the combination of several modular frames as shown in FIG. 9 ;
FIG. 12 shows the top modular assembly top plate 1200 as demonstrated in the assembly of FIG. 11 ;
FIG. 13 is a schematic representation of the structure shown in FIG. 11 with a top cover assembled thereon; and
FIG. 14 is a schematic representation of the structure shown in FIG. 11 with a parabolic shaped top cover assembled thereon.
FIG. 15 is a schematic representation of a modular frame with support members 1510 and 1520 of varying length.
DETAILED DESCRIPTION
An embodiment of the disclosure relates to a wide-span modular free-standing structure. The modular structure combines the structural components of the fabric top with the structural elements of the support frame, eliminating the need for the additional roof-support bracing. While the top may have many geometric forms, in one embodiment the top is substantially octagonal. The octagonal top frame along with geodesic corners provides converge to the supporting legs with the built in parabolic shaped top. It also provides the necessary flowing curvature for water removal, while integrating structural tensioning of the top from the perimeter structural frame forms the base tent unit.
The octagonal perimeter frame of equal or unequal side dimensions provides support only at the four corners, thereby providing clear side openings, based upon the tent size, from 10 feet to 40 feet or larger. Due to structural requirements for snow or wind loadings, an interior wire cable system may be optionally added, along with a cable to fabric top tensioning rod to offset the loading needs. A tent according to one embodiment of the disclosure can incorporate conventional slip fit design elements for the octagonal perimeter frame, geodesic corners and the vertical legs.
The structural components (base plates, frame pipe fittings, pipes and modular assembly elements) can be constructed from any structural material products, including but not limited to steel, aluminums, plastics and composite products (i.e., carbon fiber) and alloys. The parabolic-shaped top can be constructed from any fabric which has structural supporting characteristics and can have either sewn or welded joints. Sidewalls or partition walls can be either attached to the fabric or side frame members and constructed from any fabric which has structural supporting characteristics and can have either sewn or welded joints. These walls can be attached with VELCRO® type connectors, zippers or webbing.
FIG. 1 is a plan view of a modular frame according to one embodiment of the disclosure. To ease description, the structure of FIG. 1 is shown without a roof top. Referring to FIG. 1 , the free-standing modular frame 100 includes base-plate. The base-plate defines a footprint which is the perimeter of the structure. That is, by drawing an imaginary line between the adjacent base-plates, a footprint for the structure can be determined. The base-palate 110 is shown to have several connections points for securing the structure to the ground. The connection points can be sized to receive an anchor or the like. Base plate 110 may have an integrated structure to receive one or more legs 101 . For example, FIG. 1 also shows base plate 112 adapted to support two legs 102 . Each leg couples (or connects) to a geodesic corner structure 120 . The geodesic corner structure 120 comprises of at least three structural members coupled to each other to substantially form a triangle. The geodesic corner structure 120 may be adapted to receive more than one leg as shown in the geodesic structure 122 . While the geodesic corner structure is shown as having three members forming a triangle, the principles disclosed herein are not limited thereto. Indeed, a corner structure not resembling the triangular shape shown in FIG. 1 , for example a parabolic structure can be used without departing from the principles of the disclosure.
Structural support members 130 connect the geodesic structures to each other and can be seen as interposed between two adjacent geodesic structures. The connection of the support members and the geodesic structures forms perimeter 135 , which in the non-limiting embodiment of FIG. 5 , is octagonal. Parameter 135 provides a frame for receiving the roof-top material for the modular tent.
FIG. 1 also shows cross-members 105 connecting support members 130 to each other. Cross-members can be tension wires, bars, rods or any other conventional structural mean. As shown in FIG. 1 tension wires 105 and 106 meet at center point 107 . While not shown in FIG. 1 , a support bar can be placed at the center point 107 between the top tension wire 105 and the bottom tension wire 106 or above both wires ( 105 and 106 ) to the underside of the fabric top, to create a peak at the center of the modular structure 100 . Once parameter 135 is covered by a roof-top material, the peak at center 107 will help repel water and debris. Thus, a peak is provided without the need to have a separate roof-support member that disrupts the space inside the structure. FIG. 1 also shows footprint 150 which is the surface area defined by foot-prints 110 (and 112 ).
While the exemplary embodiment of FIG. 1 shows cross members 105 and 106 connecting support members 130 which are opposite to each other, the principles disclosed herein are not limited thereto and can apply to cross-members which couple (or connect) adjacent support members.
It should be noted that because FIG. 1 is a plan view of a modular frame, the perimeter 135 may appear smaller than the foot-print of the modular frame. However, as will be demonstrated in side-view FIG. 3 , such is not the case.
FIG. 2 is a schematic representation of an exemplary modular frame having the roof fabric assembled to the top of the modular frame pipe thereon. Referring to FIG. 2 , modular frame 200 is shown with legs 101 supporting geodesic corner structure 120 . A roof fabric 210 covers the top surface of the structure formed by the plurality of support members 130 and geodesic corner structures 120 . The roof fabric can be extended to cover the space supported by each geodesic corner structure as is shown by regions 215 . In the exemplary embodiment of FIG. 2 , additional tension wires 220 adjoin opposite corners. The implementation of tension wires 220 is optional. In an alternative embodiment, the tension wires are support rods configured to provide a small slope or a slant by raising the center point 225 slightly above the support members 130 . Such configuration enables the modular frame to shed water and debris. This top can be used to cover an individual wide span modular free standing structure or incorporated to cover the same frame, reconfigured to form a larger modular component interior clear span frame tent.
FIG. 3 is a side view of a portion of the modular structure shown in FIG. 1 . In FIG. 3 , base-plate 112 receives legs 102 . Each leg 102 connects to geodesic corner structure 120 through a different joint 310 , 312 . Additional joints 314 and 316 define the geodesic corner structure 120 . Bars 330 , 332 and 334 can be fabricated from any conventional material including, aluminum, titanium, steel, carbon fiber, etc.
Because FIG. 3 is a side view, it can be readily seen that the coverage area of the roof top supported by roof parameter 135 is substantially similar to that the of the foot-print perimeter of the modular structure. In one embodiment, the size of the parameter 135 is substantially the same as the parameter defined by the base-plates 110 . In another embodiment, the surface area of the foot-print is substantially equal to the surface area of the roof combined with the surface area of the geodesic portions.
FIG. 4 is a plan view of an embodiment of the disclosure having parabolic top 410 . Parabolic-shaped top 410 can be made of any conventional material having structural value including, for example, vinyl, PVC, canvas, etc. The parabolic-shaped top extends to cover the geodesic portions 415 . The parabolic-shaped top can be attached to the bottom side of the modular frame and can have a parabolic shape which creates a curvature from the center of the top to the corners, providing for drainage and debris removal. This parabolic-shaped top also provides a structural bracing of the modular frame to reduce lateral movement from the wind.
FIG. 5 shows the exemplary joint 500 which can be use in connection with the principles disclosed herein. Joint 500 generally has an elbow shape and may form a right-angle. Opening 510 can be sized to receive a leg, a part of the geodesic structure or cross members. An optional notch 520 is formed on each side of the joint to receive a complementary ball or release mechanism. From the member which is received by the joint.
Similarly, FIG. 6 shows a three-way joint for connecting three members. Again, notches 620 can be optionally formed to secure an adjoining member with a complementary ball or release mechanism. FIG. 7 represents the three-way joint of FIG. 6 from a different angle. A similar numbering scheme is used in FIG. 7 to identify the various portion of the three-way joint.
FIG. 8 shows an exemplary base plate adapted to receive two legs. Base plate 800 is shown to have four holes 805 formed therein. Holes 805 can be devised to receive an anchor bolt securing the base plate to the ground. Receiving tubes 810 can also be integrated to base plate 800 . Each receiving tube 810 can releasably receive, for example, a leg of the modular frame 100 as shown in FIG. 1 . Opening 812 can be sized to accommodate the appropriate members while rejecting others. Notch 814 is formed in the receiving tubes 810 to releasably engage a structural member or a leg having a complementary release or attachment mechanism. Cavity (or marker) 815 can be positioned centrally within the base plate to identify the tent frame size and provide a reference point for laying out the base plates prior to assembling the structural components.
According to one embodiment of the disclosure several modular frames can be combined to form a larger structure. FIG. 9 shows a modular frame adapted to combine with similar frames to form a larger structure. Referring to FIG. 9 , three of base plates 905 are positioned on the ground and adapted to receive two legs 910 each. In addition, each of base plates 905 supports a geodesic corner structure 920 . Geodesic corner structure 925 is coupled to leg 915 which ends in base plate 917 . Geodesic corner structure 925 as well as leg 915 and base plate 917 are rotated to point up-ward and away from the ground.
FIG. 10 shows the modular frame of FIG. 9 with roof cover 1010 assembled thereon. It can be readily seen that cover 1010 extends to cover geodesic corner structure 925 which is turned upward.
When creating a larger interior clear span modular frame tent, four of the basic Modular Frames can be grouped together. Three of the geodesic corner and leg assemblies of each modular frame, are assembled normally; while the fourth is reversed, with the geodesic corners and leg assembly pointed upward. The four center geodesic corners and leg assemblies are attached to the Top Modular Assembly Base plate 1200 , which allow the structural forces from the center to be balanced against each other when assembled. Due to structural requirements for snow or wind loadings, an interior wire cable system may be added between the octagonal frames. Opening the center of the Modular Assembled tents, in distances of 20 feet to 80 feet or larger, allows the larger clear spanned area to be available, while maintaining the larger clear side openings. This configuration of Modular Frames to create larger structures without special beam or truss span components, thereby reducing the quantity of perimeter legs while obtaining the larger clearance spaces and reducing the time needed to set up these larger tents.
FIG. 11 shows the combination of several modular frames as shown in FIG. 9 . Namely, FIG. 11 shows the combination of modular frames 110 , 1104 , 1106 and 1110 . At the point where each two modular frames join (e.g., frames 110 and 1106 ) the legs can be supported by a specially-adapted base plate 1120 which can accommodate 2 or more legs or use the standard leg base plate connected adjacent to each other. Additional joiner elements (not shown) that couple other members (e.g., legs) of the coupled frames may optionally be used. As shown in FIG. 11 each frame 1102 , 1104 , 1106 , and 1110 will have one geodesic corner structure and leg turned upward. The upwardly-facing geodesic corner structures and legs for each of the modular frames can be joined at the center to form center peak 1130 . Peak 1130 provides a means for shedding water and other debris and provides structural stability. To provide additional structural stability, the legs from the joinder of the geodesic corners can be coupled through top plate 1135 or similar devices. Further structural rigidity can be provided by optionally assembling tensions wires 1140 and 1145 which connect support members 1112 , 1114 , 1116 and 1118 .
Cross members 105 are also shown in FIG. 11 . These cross members can be tension wires separated by a spacer (not shown) such that the top tension wire is slightly elevated over the bottom tension wire. Thus, each of the modular frames 1102 , 1104 , 1106 and 1110 , when covered by a roof material will have a slight peak for shedding water.
FIG. 12 shows top plate 1200 as demonstrated in the assembly of FIG. 11 . In FIG. 12 , top plate 1200 includes several receiving tubes 1210 . Each receiving tube 1210 is sized to releasably receive a leg member associated with a modular frame of the structure. Top plate 1200 also shelters the opening at top of peak 1130 (see FIG. 11 ).
FIG. 13 is a schematic representation of a modular structure 1300 including the structure shown in FIG. 11 with a top cover assembled thereon. The top cover in this schematic is attached to the top of the modular frame assembly pipe. The modular frame 1300 can be devise so as to minimize seams 1310 . Alternatively, seam covers (not shown) can be provided to obviate water leakage.
FIG. 14 is another schematic representation of a modular structure 1400 including the structure shown in FIG. 11 with a top cover assembled thereon. The top in the representation of FIG. 14 is a parabolic top which can be attached to the underside of the modular frame pipe. The openings between the modular frame parabolic tops is closed with a joint cover (not shown) to obviate water leakage.
It can be seen that the embodiments disclosed herein provide a structural frame that, among other: (1) reduces the visual obstruction of standard tent roofs; (2) reduces the length of pipe components required to construct a frame tent; (3) reduces assembly and disassembly time; and (4) increases the width size of slip joint frame constructed tents.
The embodiments disclosed herein are exemplary in nature and are not intended to limit the scope of the principles disclosed and/or claimed herein. Other embodiments which are not specifically described herein can be made in accordance with the principles of the disclosure and within the scope of these principles.
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In one embodiment, the disclosure relates to a free-standing structure which includes an eight-sided roof perimeter; at least four geodesic structures extending from four sides of the eight-sided roof perimeter and supporting the perimeter; and at least four legs, each leg structurally corresponding with one of the at least four geodesic structures for upholding the free-standing structure.
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This is a continuation of copending application Ser. No. 07/544,582 filed on Jun. 27, 1990.
CROSS REFERENCE TO CO-PENDING APPLICATIONS
The present application is related to Ser. No. 919,044, filed Jul. 23, 1992, and entitled Catheter Lumen Occluder, assigned to the same assignee.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to devices used to clear obstructions in body passage ways, and more particularly, relates to means and methods of treating such obstructions by the infusion of chemical thrombolytic agents.
2. Description of the Prior Art
The use of catheter systems to treat various medical conditions has been known for some time. In treating a particular area within a body passage way, it is often desirable to isolate the treatment area from the rest of the body through the use of one or more balloons which may be inflated proximal and/or distal to the treatment area. U.S. Pat. No. 2,936,760 issued to Gants, U.S. Pat. No. 4,022,216 issued to Stevens, and U.S. Pat. No. 4,705,502 issued to Patel describe catheters designed for use in the urinary tract.
Such catheter systems are also used in other applications. U.S. Pat. No. 4,696,668 issued to Wilcox, for example, describes a catheter system for treatment of nasobiliary occlusions. Similarly, U.S. Pat. No. 4,198,981 issued to Sinnreich is used in intrauterine applications. U.S. Pat. No. 4,453,545 issued to Inoue teaches an endotracheal tube.
One of the most common applications for catheter systems is the treatment of occlusions within the cardiovascular system. A catheter system for venous applications is seen in U.S. Pat. No. 4,795,427 issued to Helzel. U.S. Pat. No. 4,636,195 issued to Wollinsky, U.S. Pat. No. 4,705,507 issued to Boyles, and U.S. Pat. No. 4,573,966 issued to Welkl et al., all describe catheter systems designed to infuse a liquid for the treatment of an arterial occlusion. Each of these devices has one or more balloons to occlude the artery during the treatment process.
U.S. Pat. No. 4,655,746 issued to Daniels et al. proposes the use of two concentric catheters each having its own occlusion balloon to adjustably isolate a portion of the body passage way. The Daniels et al. design, however, requires the use of the interlumenal space as a fluid passageway, thereby complicating the construction and operation of the device. Use of the interlumenal space as a fluid passageway also may undesirably alter the handling characteristics depending upon the specific application and the degree to which the interlumenal space is pressurized.
A recognition of the need the improve to efficiency of the infused liquid is found in U.S. Pat. No. 4,423,725 issued to Baran et al. Unfortunately, the system of Baran et al. employs a middle balloon for forcing the liquid into the side walls of the artery. For arteries having insufficient resiliency, the high pressures in the isolated area tend to be equalized by expelling fluid and/or occluding material past the occluding balloons and out of the treatment area. In extreme cases, rupture of the arterial wall may be envisioned.
SUMMARY OF THE INVENTION
The present invention provides an apparatus and method for treating an occlusion in a body passage way, such as an artery, through the infusion of a fluid. Two balloons are used to isolate the treatment area from the remainder of the body. Because each of the balloons is located at the distal end of a different one of two concentric catheters and the inner catheter is slidable with respect to the outer catheter, adjustment of the interballoon distance and, therefore, the size of the isolated treatment zone is easily accomplished. However, because the interlumenal space is not used as a fluid passage way, the interballoon distance can be rapidly modified to increase or decrease the size of the isolated treatment zone.
A thrombolytic agent is infused into the isolated treatment area through orifices in the inner catheter. The thrombolytic agent may be streptokinase, TPA, or a similar chemical agent. As the lesion within the treatment area is exposed to the thrombolytic agent, some of the material is dissolved and removed by aspiration through lumens in the outer catheter.
Efficiency of the treatment is greatly enhanced by agitating the treatment area at ultrasonic frequencies. Ultrasonic energy is supplied by transducer(s) attached to the inner catheter within the isolated treatment area. Similarly, efficiency of aspiration is enhanced by ultrasonic agitation in the region of the aspiration ports of the outer catheter.
A pressure sensor within the isolated area is used to maintain the pressure within safe limits. Excess pressure tends to circumvent the balloon seals at the ends of treatment area. Too little pressure may cause collapse of the arterial wall under extreme conditions.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects of the present invention and many of the attendant advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, in which like reference numerals designate like parts throughout the figures thereof and wherein:
FIG. 1 is a plan view of a preferred embodiment of a catheter system employing the present invention;
FIG. 2 is an exploded view of the catheter system of FIG. 1;
FIG. 3 is a cross-sectional view of the catheter system of FIG. 1;
FIG. 4 is a cross-sectional view showing one method of occluding the open lumen of the inner catheter;
FIG. 5 is a cross-sectional view of an alternative means of occluding the open lumen of the inner catheter;
FIG. 6 is a longitudinal cross-sectional view of the embodiment of FIG. 5; and,
FIG. 7 is a detailed exploded view of the electrical connections at the proximal end of the catheter system.
FIG. 8 is a cross sectional view of the aspiration ports of an alternative embodiment.
FIG. 9 is a plan view of the catheter system having the alternative embodiment of the aspiration ports.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 is a plan view of a thrombolysis catheter system 10 employing the present invention. The main body of catheter system 10 consists of a guide wire 11, an inner catheter 72, and an outer catheter 70, each of which is discussed in detail below.
At the proximal end of the catheter system, electrical and fluid access to the various lumens of catheter system 10 is provided by branch assemblies 18 and 42. Branch assembly 18 is at the most proximal end of catheter system 10. It consists of main branch 20 and secondary branches 22, 24, and 26. Main branch 20 couples to large open lumen 142 (shown in FIG. 3). This lumen is the pathway for guide wire 11, having proximal end 12 extending proximal to main branch 20 and having distal end 14 extending distal to the distal end of inner catheter 72. Guide wire 11 must be sealed to main branch 20 by screwing sealing nut 30 to threads 31.
Secondary branch 22 couples to inflation lumen 144 (see also FIG. 3). An inflation unit (not shown) is coupled to secondary branch 22 via standard hub 32. This permits inflation and deflation of balloon 86 at the distal end of inner catheter 72. Balloon 86 is used to provide the distal occlusion point of the isolated area under treatment.
Secondary branch 26 provides electrical coupling with electrical lumen 146 of inner catheter 72. This electrical coupling requires a minimum of two conductors to power the ultrasonic piezo-electric strip 80 (described below) which improves the efficiency of the system through agitation. Electrical plug 38 couples to standard hub 36 as further explained below. Cable 40 couples to an ultrasonic signal generator (not shown). An optional pressure transducer located on inner catheter 72 requires a third dedicated conductor and preferably shares one of the other two conductors which power the ultrasonic transducer.
Large open lumen 142 of inner catheter 72 is also used for infusion of the thrombolytic agent. To accomplish this, sealing nut 30 must firmly seal the proximal end of main branch 20 against guide wire 11 to prevent fluid from escaping proximally. Secondary branch 24 is also in fluid communication with large open lumen 142 of inner catheter 72. The thrombolytic fluid is introduced to the catheter system 10 via secondary branch 24 by coupling an appropriate pumping device (not shown) to standardized hub 34.
Branch assembly 18 is sealingly coupled to inner catheter 72 by threaded coupling 28. Inner catheter 72 is adjustably sealed to branch assembly 42 by sealing nut 62 tightly engaging threads 64. The adjustability provided by this configuration is required to provide adjustment of the interballoon spacing. Branch assembly 42, like branch assembly 18, is preferably molded of a rigid plastic. Electrical and fluid contact with the various lumens of outer catheter 70 is established by branch assembly 42.
Secondary branch 46 provides fluid coupling to balloon inflation lumen 122 (see also FIG. 3). A pumping device (not shown) is coupled to standard hub 52 of secondary branch 46 to permit inflation of balloon 74 of outer catheter 70. Inflation of balloon 74 occludes the artery proximal to the treatment area, which along with inflation of balloon 86 as discussed above, isolates the treatment area from the rest of the body.
Electrical lumen 124 (see also FIG. 3) of outer catheter 70 is coupled to secondary branch 50. In the preferred mode, two conductors are used in electrical lumen 124 to power ultrasonic transducer band 76. This element provides agitation adjacent to the aspiration ports to prevent clogging. Electrical plug 58 couples to standard hub 56 as further explained below. Cable 60 couples to an ultrasonic signal generator (not shown).
Fluid communication is established with aspiration lumens 126, 128, 130, and 132 by secondary branch 48. In operation a vacuum device (not shown) is coupled to standardized hub 54 of secondary branch 48. Aspiration removes the particles of occluding material as they are dissolved from the arterial wall by action of the thrombolytic agent.
Branch assembly 42 is sealingly coupled to outer catheter 70 at point 68 by tightly screwing threaded coupling 66 onto threads 65. The main length of catheter assembly 10 extends from sealing point 68 to balloon 74 and is about 150 cm.
Balloon 74 is inflated by standard means (e.g. pressurized sterile saline) from secondary branch 46 via inflation lumen 122. The major purpose of this balloon is to provide a proximal sealing of the treatment area. This sealing, combined with the distal seal of balloon 86, ensures that the body is not subjected to systemic side effects from the application of the thrombolytic agent. It also prevents particulate material released from the lesion from being circulated before it can be adequately aspirated.
Just distal of balloon 74 is ultrasonic transducer band 76. It is electrically coupled through electrical lumen 124 and secondary branch 50 to cable 60 and the ultrasonic signal generator. Ultrasonic transducer band 76 is preferably a commercially available piezoelectric strip. It is positioned adjacent the aspiration ports to provide agitation to improve aspiration efficiency. In the preferred embodiment shown, the aspiration ports are located at the very distal tip 78 of outer catheter 70.
Inner catheter 72 is slidingly engaged in lumen 120 of outer catheter 70 (see also FIG. 3). The sliding engagement permits the interballoon distance to be readily adjusted. As explained above, balloon 86 is inflated from secondary branch 22 through inflation lumen 122. The large open lumen 142 (see also FIG. 3) of inner catheter 72 is used as the lumen for guide wire 11. After the operational position has been achieved and both balloon 74 and balloon 86 have been inflated, large open lumen 142 is occluded at both proximal and distal ends to close it for use as an infusion lumen. Occlusion at the proximal end is accomplished by sealing nut 30 as explained above. Distal orifice 88 of large open lumen 142 may be occluded by positioning seal 16 sealingly against distal orifice 88. Alternative techniques for sealing orifice 88 are described below.
After the treatment area has been selected by sliding inner catheter within outer catheter 70, the treatment area has been isolated by inflation of balloons 74 and 86, and large open lumen 142 has been occluded both proximally and distally, the thrombolytic agent is infused through secondary branch 34. The thrombolytic agent is infused into the treatment area via orifices 82a, 82b, 82c, through 82n which are coupled to large open lumen 142. Efficiency of the system is improved by ultrasonic agitation supplied by commercially available piezo-electric strip 80, which is helically wound between the infusion orifices as shown. Piezo-electric strip 80 is electrically powered by conductors in electrical lumen 146 coupled through secondary branch 26 to cable 40.
A pressure transducer 84 is optionally positioned within the treatment zone to monitor pressure. This monitor permits coordination of infusion and aspiration volume to maintain the pressure within the isolated zone at a safe level.
FIG. 2 shows an exploded view of the components of catheter system 10 wherein like reference numerals are as previously described. Of particular note are female electrical connectors 100 and 106 coupled to conductors 102 and 104, and conductors 108 and 110, respectively. Female electrical connectors 100 and 106 are fixedly attached within standard hubs 56 and 36, respectively. Additional detail is supplied below.
FIG. 3 is a cross sectional view of the main body of catheter system 10. It consists of inner catheter 72 snugly but slidably inserted into large central lumen 120 of outer catheter 70. Inner catheter 72 is extruded with large open lumen 142 which is used for the passage of guide wire 11 and for infusion of a thrombolytic agent as explained above.
Inner catheter 72 has two smaller lumens. Infusion lumen 144 is used to inflate balloon 86. Electrical lumen 146 carries the conductors which power piezo-electric strip 80.
Outer catheter 70 has a large central lumen 120 for passage of inner catheter 72. Infusion lumen 122 provides for inflation of balloon 74. Electrical lumen 124 provides for passage of the conductors to power ultrasonic band 76. Aspiration is performed through aspiration lumens 126, 128, 130, and 132. Each represents slightly less than 90 degrees of a coaxial, concentric lumen. Septal areas 134, 136, 138, and 140 separate aspiration lumens 126, 128, 130, and 132 and provide resistance to lumenal collapse.
FIG. 4 is a cross sectional view of an alternative technique for occluding the distal end of large open lumen 142 prior to use for infusing the thrombolytic agent. In this embodiment, seal 16 may be omitted from guide wire 11 (see also FIG. 1). Occlusion of large open lumen 142 is accomplished by inflating interior balloon 148 from infusion lumen 144. Interior balloon 148 is expanded through interlumenal channel 150 to fill the cross sectional area of large open lumen 142 as shown. Additional details of the use of this technique are available in the commonly assigned, copending patent application entitled Lumen Occluder referenced above and incorporated herein by reference.
FIG. 5 is a cross sectional view of another alternative technique for sealing the distal end of large open lumen 142. With this approach, interior balloon 152 is located under balloon 86. When balloon 86 is inflated to position 87 by inflation port 144, interior balloon 152 is similarly inflated to fill interlumenal channel 154 and large open lumen 142. Again, further details concerning this technique may be found in the above referenced, commonly assigned, copending application.
FIG. 6 is a longitudinally sectioned view of the alternative embodiment of FIG. 5, wherein referenced elements are as previously described. In this view, interior balloon 152 expands to position 153 when inflated.
FIG. 7 is an exploded view showing the detail of the electrical connections. Conductors run the length of electrical lumen 146 of inner catheter 72 from piezo-electric strip 80 (see also FIG. 1) to female connector 100. Distal tips 160 and 162 are electrically coupled to female sockets 164 and 168. Female connector 100 is frictionally engaged within grooved lumen 172 of hub 56.
Terminal pins 174 and 176 releasably engage within orifices 166 and 170, respectively, of female connector 100. Terminal pins 174 and 176 are electrically coupled to different ones of the conductors of cable 60. As explained above, cable 60 is coupled to an ultrasonic signal generator (not shown).
Terminal pins 174 and 176 are held in contact with female sockets 164 and 168, respectively, by rotation of electrical plug 58 in the direction of arrow 182 to engage with hub 56 as with conventional Luer assemblies. To facilitate the connection, electrical plug is provided with a smoothly sloping conical portion 178 and strain relief 180.
The electrical connection between electrical plug 38 and female socket 106 operates in similar fashion except that it contains an optional third conductor to accommodate pressure transducer 84 as explained above. Conductors 106, 107, and 108; distal tips 184, 185, and 186; female sockets 188, 189, and 190; orifices 192, 193, and 194; terminal pins 196, 198, and 200; smooth conical shape 202; and strain relief 204 functions as explained above.
FIG. 8 is a cross sectional view of an alternative technique for implementing the aspiration ports. In the preferred mode of FIG. 1, outer catheter 70 is simply terminated at distal point 78 and therefore the aspiration lumens 126, 128, 130, and 132 are open in the distal direction. This configuration is most useful for very small diameter arteries.
In the alternative embodiment of FIG. 8, the aspiration ports are configured to open laterally, which works well with arteries of larger diameter. Aspiration ports 308, 310, 312, and 314 are in fluid communication with corresponding aspiration lumens as shown. The inflation and electrical lumens are sealed with plugs 316 and 318, respectively.
FIG. 9 is a plan view of a thrombolytic catheter system which is identical to the catheter system of FIG. 1 except that it employs the aspiration ports shown in FIG. 8 of which only port 308 is shown.
Having thus described the preferred embodiments of the present invention, those of skill in the art will readily appreciate that other embodiments may be practiced without deviating from the scope of the claims hereto attached.
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An apparatus and method for dissolving and removing material which tends to occlude a body passage way, such as an artery. The device employs a dual catheter system arranged in coaxial fashion. Each of the catheters has an inflatable balloon at its distal tip. Inflating the two balloons occludes the body passage way both proximal and distal to the treatment area, thus isolating it from fluid contact with the rest of the body. Because concentric catheters are used, the distance between the balloons and hence the size of the treatment area is adjustable. The thrombolytic agent is infused through orifices in the inner catheter in the region between the two balloons. A piezo electric device supplies ultrasonic agitation within the treatment area. A pressure device monitors the body passage way for unsafe conditions. Aspiration is accomplished through one or more lumens in the outer catheter. Ultrasonic agitation may be employed with the aspiration also to break up masses of material which may be too big to pass through the exit lumen cross section.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a data protection device and a method of securing data, and in particular to a device installation that supports all types of storage media interface with higher data access rate and more efficient usage of disk space.
2. The Related Art
Conventional data protection is based on the hardware implementation of a data protection circuit, which is installed between a conventional hard disk interface and the data bus. For the operating system, the specially adapted hard disk is treated as a conventional hard disk, with no need of any driver programs. Data can be written directly into a data storage device without any driver programs. Therefore, the data access rate of the hard disk is not affected, only that the disk operation has become more secure.
However, there is a limitation to using the prior art data protection technique, which can only be used on the storage media interface that is invariably set for two IDE hard disks or logical drives. After assigning the disk space for the primary data area and the virtual data area, the disk space remaining is allotted to logical drives, which is the disk space that a user can utilize. But this prior art data protection technique cannot be used on newer generation of storage media interface cards that are often used on a single hard disk, such as SATA. Therefore, the operation mode and architecture of the prior art technique need to be adjusted to meet the requirements of current hard disk technology.
Another inherent weakness in the architecture and the operation mode of the prior art technique is that the allotment of disk space to the primary data area and the virtual data area has to be equal. Since the data address of the saved in a hard disk might not be contiguous, the one-to-one copying of the entire data block though easy to implement often is a waste of the disk space. Therefore, the overall data access rate is slowed down because of the unnecessary disk action on the non-data sectors.
Since the prior art technique adopts the one-to-one copying, the system can only perform inflexible data copying and data recovery, but such system cannot support multiple node data protection and multiple selection of data reference point for archiving and data restoration.
SUMMARY OF THE INVENTION
The primary objective of the present invention is to provide a data protection device that supports all types of storage media interface.
The secondary objective of the invention is to provide a data securing technique that makes use of data flags recorded in a sector index table to indicate the write status of certain sectors when data are written into certain sectors, whereby the disk space needed for archiving can be considerably reduced, and the overall data access rate can be shortened.
The third objective of the invention is to provide a data securing technique that enables users to define the data reference point for archiving and data restoration operations, such as certain hour or date, and supports multiple node data protection through overlapping data copying and restoration processes.
In accordance with the first aspect of the invention, the data protection device is composed of a disk space allotment unit, a marking unit and an archiving unit.
In accordance with the second aspect of the invention, the disk space allotment unit is to reorganize multiple sectors existing in the data storage device for allotment of disk space to newly defined sections, such as a working data section, a sector index table and a duplicate data section of the data protection device.
In accordance with the third aspect of the invention, the marking unit is to mark the data flag of a certain sector in the sector index table at the same time that data are written into the working data section, where the data flag is used to indicate whether the write status of certain sector is enabled.
In accordance with the fourth aspect of the invention, the archiving unit is to use the data flag of a certain sector marked in the sector index table to copy the data of respective sector from the working data section and associated data flag value from the sector index table to the duplicate data section.
In accordance with the fifth aspect of the invention, a data recovery unit is included in the data protection device, so that when some of the data saved in the data protection device are corrupted or the data storage device is attacked by computer viruses, the user is able to invoke the data recovery procedure to restore the original data in the working data section using the data copy from the duplicate data section.
In accordance with the sixth aspect of the invention, a disk space tracking unit is to collect updated information of disk space used so far and disk space still remaining in the working data section, the sector index table, and the duplicate data section.
In accordance with the seventh aspect of the invention, every time when the archiving unit or the data recovery unit is invoked, the disk space tracking unit is first consulted to obtain updated information about the disk usage in order to prevent overwriting of any valid data in the destination data section. Also, through the service of the disk space tracking unit, the user is able to obtain useful information about the disk usage in the working data section, the sector index table and the duplicate data section continuously for other applications.
The present invention will become more obvious from the following description when taken in connection with the accompanying drawings, which show, for purposes of illustration only, a preferred embodiment in accordance with the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of the first embodiment of the present invention;
FIG. 2 is a disk space allotment diagram in accordance with the present invention;
FIG. 3 is a diagram showing the data pattern in the working data section and respective data flags marked in the sector index table;
FIG. 4 is a diagram showing the data pattern in the duplicate data section being derived from the data patterns shown in FIG. 3 ;
FIG. 5 is a block diagram of the second embodiment of the invention;
FIG. 6 is a block diagram of the third embodiment of the invention;
FIG. 7 is a block diagram of the fourth embodiment of the invention; and
FIG. 8 is a block diagram of the fifth embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1 , a data protection device 10 in the first preferred embodiment of the present invention is composed of a disk space allotment unit 18 , a marking unit 20 and an archiving unit 22 . Further, the data protection device 10 is connected by a host interface 12 to a data communication line (not shown), so that the operating system is able to access data saved in a data storage device 16 connected through a peripheral interface 14 .
The data securing technique employed by the data protection device 10 in accordance with the present invention bears some resemblance to the prior art technique, such as the use of the conventional data copying and restoration procedures for manipulation of data in the data storage device, but the present invention has introduced the re-allocation of the entire disk space on the storage device so as to achieve higher data access rate and more efficient usage of disk space, in which multiple sectors existing in the data storage unit 16 are first reorganized for allotment of disk space to newly defined sections, such as a working data section, a sector index table and a duplicate data section.
Referring to FIG. 2 , the disk space allotment for the working data section 30 , sector index table 31 and duplicate data section 34 in accordance with the present invention is shown. The disk space allotment unit 18 is to implement the allotment instruction given by the user through an input device. The entire disk space of the data storage device 16 is reconstructed, that is multiple sectors on a hard disk are reorganized to create the working data section 30 , the sector index table 31 and the duplicate data section 34 . At the same time, the disk space allotted to each section is defined. It shall be noted that data manipulation in the working data section 30 , the sector index table 31 and the duplicate data section 34 of the data protection device 10 still uses the conventional data read/write signals.
Referring to FIG. 3 , the data pattern existing in the working data section and the sector index table is shown. The operating system has ‘FF’, ‘00’, ‘15’, ‘A1’, and ‘B0’ written into sectors 30 A to 30 E, while the sectors 30 F to 30 I are still empty at this point.
When the operating system is about to write data into a certain sector of the working data section 30 , such as the data content in sector 30 A, the marking unit 20 is to check and mark the data flag 32 in the sector index table, which indicates whether valid data are present in the sectors 30 A to 30 F. If the sector 30 A has data content ‘FF’, then the data flag 32 of respective sector shall be marked as ‘1’ indicating valid data are present in the sector 30 A, but if the sector 30 B does not have any data, the data flag 32 of respective sector in the sector index table 31 shall be marked as ‘0’.
Referring to FIG. 4 , the data pattern in the duplicate data section is being derived from associated data pattern in the working data section and sector index table shown in FIG. 3 . When the archiving procedure is invoked, the archiving unit 22 first checks the data flag 32 of a certain sector marked in the sector index table 31 before the data in the working data section 30 is copied to the duplicate data section 34 , such as the sector 30 B with data flag status ‘0’ which indicates the sector 30 B does not have any data, so the archiving procedure will skip over the sector to the next one, thus one sector is saved for more meaningful data. The associated data flag value is also copied to the duplicate data section 34 as shown in FIG. 4 , but it is not necessary to put the data flags 32 in front of regular data as demonstrated in the present example.
The present invention is characterized in that the disk space used by the working data section 30 and the duplicate data section 34 does not have to be equal, unlike the prior art technique. Since the storage media interface used by the data protection device 10 is not limited to supporting two disk drives, the present invention is able to support any type of storage media interface, so the number of disk drives being connected can be changed for different system configurations.
The marking unit 20 of the data protection device 10 is used to record the data flags 32 of all sectors used by the working data section 30 in the sector index table 31 , so that, for example, sector 30 B with no data shall be skipped over in the archiving procedure. This can also explain why the disk space used by the working data section 30 and the duplicate data section 34 does not have to be the same.
Referring to FIG. 5 , the second embodiment of the invention is presented, in which a data recovery unit 24 is included in the data protection device 10 . If some of the data saved in the data protection device 10 are corrupted or when the data storage device is attacked by a computer virus, the user is able to invoke the data recovery unit 24 to restore the original data in the working data section 30 using the data copy from the duplicate data section 34 .
When the data recovery procedure is invoked, the data recovery unit 24 uses the data flags 32 of certain sectors marked in the sector index table 31 as shown in FIG. 4 to restore the data originally written in sectors 30 A, 30 C, 30 D, and 30 E of the working data section 30 , using the data copy in the duplicate data section 34 . Since the data flags 32 in the sector index table 31 indicate that the sector 30 B does not have any data, the data recovery unit 24 shall fill the sector 30 B of the working data section 30 with blank data ‘00’ in the data recovery procedure.
Referring to FIG. 6 , the third embodiment of the invention is presented. If the data content in the sectors 30 F to 30 I of the working data section 30 is arranged as ‘14’, ‘15’, ‘00’, and‘17’, that means the sector 30 H does not have any data. In this case, the data flag 32 originally used in the first embodiment is to add a new data flag entry 40 with the data arrangement‘1, 1, 0, 1’. Therefore, in case the user sets up another data protection node, the archiving unit 22 is first to check on the data flags 32 , 40 in the sector index table 31 and then data saved in sectors 30 A to 30 I in the working data section 30 are copied to the duplicate data section 34 , together with associated data flag values as shown in FIG. 6 .
Using the same data manipulation, in the event of a computer disaster, data need to be restored to the working data section 30 , the data recovery unit 24 is first to check on the data flags 32 , 40 in the sector index table 31 , and then respective data in the duplicate data section 34 are copied to the sectors 30 A to 30 I of the working data section 30 , and the data in the working data section 30 before the disaster occurs. The data flags 32 , 40 of the respective sectors are also restored to the original values in the sector index table 31 .
Referring to FIG. 7 , the fourth embodiment of the invention is presented, in which a disk space tracking unit 70 is included in the data protection device 10 . The function of the disk space tracking unit 70 is to collect updated information of remaining disk space and occupied disk space in the working data section 30 , the sector index table 31 , and the duplicate data section 34 . Each time when the archiving unit 22 is invoked to copy data into the duplicate data section 34 , the disk space tracking unit 70 is first to be consulted to obtain an updated information about the disk usage in order to prevent overwriting of any valid data. Also, through the service of the disk space tracking unit 70 , the user is able to obtain useful information about the disk usage in the working data section 30 , the sector index table 31 and the duplicate data section 34 continuously for other applications.
Referring to FIG. 8 , the fifth embodiment of the invention is presented, in which a backup interface 26 is included in the data protection device 10 . This backup interface 26 enables data line connection between the data protection unit 10 and the data backup device 28 , so that the data protection unit 10 is able to retrieve data from the data backup device 28 . In case the disk space allotment unit 18 has assigned multiple sectors of the data backup device 28 to the duplicate data section 34 , the archiving unit 22 is able to use additional disk space on the data backup device 28 .
The backup interface 26 is to use a suitable bus interface, such as the small computer system interface (SCSI), the fiber channel interface (FC), the peripheral component interconnect (PCI), the flash card interface, the serial storage architecture (SSA), the integrated device electronics (IDE), the universal serial bus (USB), IEEE 1394, the personal computer memory card international association (PCMCIA), serial ATA (SATA), and parallel ATA (PATA).
The data backup device 28 is to use a suitable storage medium, such as a hard disk, an optical disk burner, a ZIP disk drive, a MO disk drive, a tape drive, and a card reader. Therefore, the data backup device 28 can be replaceable storage media, which enables the user reference points, such as certain hour or date, for data copying and restoration operation. However, it shall be noted that the disk space in the duplicate data section 34 shall be adjusted each time after the storage medium in the data backup device 28 is replaced so as to reflect the disk space used thus far and the disk space still remaining.
This innovative use of a sector index table containing data flags in the present invention enables the user to use less access time and disk space usage to accomplish data archiving and data recovery. Also, another feature of the data protection device is a multi-node data protection using the multiple selection of data reference point.
Although the present invention has been described with reference to the preferred embodiments thereof, it is apparent to those skilled in the art that a variety of modifications and changes may be made without departing from the scope of the present invention which is intended to be defined by the appended claims.
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A data protection device capable of securing data in a data storage device is disclosed, comprising a disk space allotment unit, a marking unit, and an archiving unit. The disk space allotment unit undertakes to reorganize multiple sectors in the data storage device for allotment of disk space to newly defined sections to be used in the present scheme, such as a working data section, a sector index table and a duplicate data section. The marking unit is to check and update the data flags in the sector index table when data are written into respective sectors of the working data section, where the data flag indicates whether the write status of certain sector is enabled. The archiving unit is to reverse the above process so as to restore the original data in the working data section and data flag in the sector index table.
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BACKGROUND AND FIELD OF INVENTION
The invention relates to a method and an apparatus for cleaning a carded sliver.
In the spinning of cotton one endeavors to remove dirt, dust, shell parts and contamination of all kinds from the cotton at almost every stage up to the spinning process. Such efforts have been successful to a large degree. However, there remains room for still further improvements.
With the increase of machine harvesting of the cotton flocks, the level of contamination of the cotton flocks has necessarily increased, so that the cleaning problem in all stages of cotton spinning is still a very real problem. In addition to this comes the fact that one endeavors to operate at high speeds of production, so that the time for carrying out cleaning processes is shorter and the requirements placed on cleanliness of the cotton are increased.
So far as it is known no proposal has so far been made for a cleaning of the carded sliver between the outlet of the card and the sliver coiler.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a cleaning process and a cleaning apparatus which, with minimal expense and without complicating the production process as a whole, cleans the carded sliver. This cleaning typically takes place between the outlet of the card (in particular after the stepped rollers which compress the card sliver) and the band coiler.
In accordance with the invention, the carded sliver is guided around at least one convexly guide surface having perforations, which leads to a spreading or loosening of the sliver. A gas stream (preferably an air stream) is generated through the perforated guide surface in order to remove loose contamination and also dust and dirt particles present in the loosened dirt.
The method of the invention thus aims at producing spreading and loosening of the sliver by guiding this sliver around a convexly curved guide surface so that on the one hand contamination contained in the sliver is itself somewhat loosened, i.e., the binding to the fibers is reduced, while the sliver itself is made more permeable for the air flow so that the cleaning action of the air flow also increases.
Although the carded sliver represents a relatively weak structure, it has sufficient strength after being compressed in the stepped rollers at the outlet of the carding machine to be drawn over a curved guide surface while being blown through without the cohesion of the sliver being disturbed and without a significant number of fibers being lost from this fiber assembly.
The gas flow which passes through the carded sliver is preferably sucked away so that both the contamination which has been separated out and any fibers which may have been freed do not contaminate the machine area. The carded sliver is preferably moved in snake-like manner around several aspirated convex guide surfaces. In this way one succeeds in cleaning the carded sliver several times within a relatively short distance and a common suction device can be used so that the total expenditure can be kept within limits.
A particularly preferred apparatus for carrying out the method is one in which the perforated guide surface is formed by a perforated cylinder which rotates in operation and within which there is provided a body having a gas outlet opening which guides the gas flow, with the gas outlet opening being arranged in the region where the sliver wraps around the cylinder.
Although a stationary guide surface is possible, the use of a rotating perforated cylinder for the guide surface has the advantage that no undesired strains arise in the carded sliver due to matching of the peripheral speed of the cylinder to the through-flow speed of the carded sliver. It is also possible to do away with a direct drive of the perforated cylinder and simply to allow the latter to rotate about its own axis of rotation together with the moving sliver as a result of the friction between the sliver and the cylinder. In this way one can indeed do away with the need for a special bearing for the cylinder, because the cylinder can simply slide on the surface of a body arranged within the cylinder. Should this not be satisfactory due to the friction which occurs, then one can also consider allowing the cylinder to be driven by the gas flow. For example, one end face of the cylinder may be formed as a turbine. As a result of the low forces that are required, causing the cylinder to act as a turbine can be achieved by simple plate surfaces and aimed blowing nozzles.
A suction means is preferably provided in the wrapping region and on the side of the carded sliver remote from the cylinder. This suction means can be exploited for a dual purpose in that it not only removes the contamination separated from the carded sliver but also partially or fully serves to generate the gas flow. Stated more precisely three possibilities exist of generating the gas flow. One may blow gas through the body, or one may generate the pressure difference required for the gas flow by the suction means, or one may use a combination of blowing and sucking in that one both charges the body guiding the gas flow with pressurized gas from a pressure gas source and also generates a suction effect through the suction means.
Several perforated cylinders are preferably provided in a row in the direction of movement of the sliver with the sliver being partly wrapped around the cylinders in snake-like manner and with a suction means being provided on at least one side and preferably on both sides of the cylinders.
In an arrangement of this kind the suction means can have the form of a box through which the carded sliver runs with the box surrounding the row of cylinders and having a suction connection.
As an alternative, the (or each) suction means can have the form of an elongate trough which tapers in the direction of movement of the carded sliver, or in the opposite direction, and which is arranged with its open side facing the carded sliver. In this preferred embodiment the suction connection is provided at the broader end of the trough. Through the use of two such suction devices, one succeeds in completely removing the loosened contamination and at least one of the suction means can be made so that it can be pivoted away so that the cylinder row is readily accessible for servicing purposes and for starting up operation of the cleaning device. The tapered form of the suction means takes account of the fact that the quantity of air in the trough increases in the direction of the suction end. Through the tapered form one can thus uniformly distribute the suction action over the cylinder row while simultaneously maintaining the speed of acceleration at the individual cylinder.
In order to avoid the sucking in of leakage air, and in order to increase the flow speeds with a moderate air consumption, provision is preferably made that the open side of the trough is only open at positions where the sliver runs between the cylinder and the trough, so that no unnecessary suction effect takes place at the rear sides of the cylinders where there is no flow through the sliver.
Although the spreading of the sliver is increased during the movement around the cylinder or cylinders, a further development of the invention envisages that the or each cylinder is also formed to execute oscillations, for example axial and/or radial oscillations and/or the gas stream is a pulsating gas stream. These represent measures which can lead to further loosening of the sliver and separation out of the dust and contaminating particles which are present.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other features and advantages of the invention will now be explained with respect to embodiments illustrated in the drawings in which:
FIG. 1 is a schematic representation of the cleaning method of the invention in which the sliver is deflected around a single aspirated cylinder;
FIG. 2 is a schematic illustration of a further apparatus of the invention with four aspirated cylinders arranged in a row and with suction means being provided;
FIG. 3 is an illustration similar to FIG. 2 but showing an embodiment having modified suction means;
FIG. 4 is an axial cross section of a variant of the apparatus of FIG. 1;
FIG. 5 is a cross sectional view of the apparatus of FIG. 4 taken along the line I--I in FIG. 4;
FIG. 6 is a cross sectional view in the axial direction of a further variant of the apparatus of FIG. 1;
FIG. 7 is a cross sectional view of the apparatus of FIG. 6 taken along the line II--II in FIG. 6;
FIG. 8 is an enlarged view similar to the portion of FIG. 7 indicated by the dot-dash line circle IV, but showing a modified construction;
FIG. 9 is a schematic illustration of another embodiment having some similarity to the apparatus of FIG. 2;
FIG. 10 is a cross sectional view in the axial direction of another variant of the apparatus of FIG. 1;
FIG. 11 is across sectional view of the apparatus of FIG. 10 taken along the section line III--III in FIG. 10;
FIG. 12 is an enlarged view similar to the portion of FIG. 11 indicated by the dot-dash line circle IV, but showing a modified construction;
FIG. 13 is a schematic illustration of an apparatus for use of the method of the invention; and
FIG. 14 is an enlarged view similar to the portion of FIG. 13 indicated by the dot-dash line circle IV, but showing a modified construction.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
FIG. 1 shows a carded sliver 10 which is deflected from the direction of the arrow 12 into the direction of the arrow 13 round a guide surface formed by a perforated cylinder 11. Within the perforated cylinder there is located a stationary body 14 which has a guide duct 15 for compressed air. The guide body is provided with a gas outlet opening 17 in the deflection region 16 of the carded sliver and this gas outlet opening is defined by two approximately radial surfaces 18 and 19 which define an angle with one another. The air supply duct 15 communicates with this air outlet opening via a slot-like duct portion 21. As can be seen in the drawing, the thickness of the carded sliver 10 is reduced from the initial thickness D to a thickness d during the deflection and attains the original thickness D again after leaving the cylinder. In the deflection region where the thickness of the carded sliver d is reduced, a spreading of the sliver takes place in the direction perpendicular to the plane of the drawing, which increases the air permeability. The spreading movement also contributes to a loosening of any dust and contaminating particles contained in the carded sliver.
The air (arrows 22) which flows out through the opening 17 penetrates the fiber sliver 10 in the deflection region and removes loose contamination and dust particles. In this embodiment the cylinder 11 is simply driven by friction with the carded sliver itself. It slides as it were on the part cylindrical rear side of the body 14.
It is however also feasible to drive the cylinder 11. This can be achieved, for example, by approximately radially directed blades on the one end face of the cylinder and blowing nozzles which cooperate with the blades and which are fed from the duct 15.
Although not shown here the air (arrows 22) which penetrates the carded sliver 10 can and will normally be removed by a suction means which covers over or surrounds the deflection region 16 of the carded sliver. It is also evident that the gas flow which is illustrated by the arrows 22 can be generated either by the connection of an air source to the duct 15 or through a suction means, as described above, or by combination of these two possibilities.
FIG. 2 shows a preferred embodiment of the apparatus of the invention. At the bottom left it is first of all shown how the sliver coming from the carding machine first runs through a funnel 23 and then through a stepped roller pair 24 at the outlet of the carding machine. Directly thereafter, the somewhat compressed carded sliver is guided in snake-like manner around four cylinders 11.1, 11.2, 11.3, and 11.4 which are arranged in a row. These cylinders can be constructed as shown in FIG. 1, however only with the difference that the opening of the respective inner body always faces the deflection region of the carded sliver at the associated cylinder. After leaving the fourth cylinder 11.4 the carded sliver passes through a funnel 250 and a pair of rollers 25 and 25.1, preferably formed as a stepped roller pair, to a sliver coiler which is only shown schematically, but not to scale, and which designated with the reference numeral 26.
Above and beneath the cylinder row there are provided respective suction devices 27 of substantially the same construction. The lower suction device has approximately the shape of an open trough which tapers in the direction of sliver movement along the cylinder row, i.e. in accordance with the arrow 28. The open side 29 of the trough faces the cylinder row. It is however covered over in the regions 31 and 32 by cover plates since here no suction is required and in this way one can avoid leakage air flows and can thus also achieve the desired high air flow speed with moderate suction power.
As can likewise be seen from FIG. 2, the suction stub 33 is arranged in the lower region of the trough so that dirt and dust particles are also transported to this point by gravity. The arrangement is also inclined so that the rear side of the trough serves as a kind of slide for the particles of contamination which are separated out there. Although the illustrated arrangement is the preferred arrangement, it is also conceivable that one could place the suction connection at the upper end instead of at the lower end if one operates with higher air flow speeds, so the danger of particles of contamination separating out before the suction connection need not be feared.
As already mentioned, the upper trough 27 is similar to the lower trough but is oriented differently, and the cover regions 35 and 36 are somewhat differently arranged. However, even these differences would be unnecessary if the upper trough 27 were so arranged that the suction connection was disposed at the top end, as is illustrated in broken lines in FIG. 2.
FIG. 3 shows a somewhat modified embodiment in which the series arrangement of four cylinders is retained and these are accommodated in a suction box 38. In this embodiment the sliver runs through two guides 39 and 41 at the entry and outlet ends of the box respectively. The suction stub 42 is provided at the lower end of the box which is arranged in an inclined position. The suction stub could however also lie at the upper end or in the middle. The arrow 22 also shows here the directions in which the air emerges from individual cylinders 11.1 through 11.4. The broken line 43 indicate how the box is constructed in two parts so that it can be opened in order to provide access to the cylinders. In this embodiment the gas guiding bodies 14 of the cylinders 11.1 through 11.4 extend somewhat beyond the end faces of the rotatable cylinders and are held at their ends in semicircular mounts in the two halves of the box 38, for example in such a way that the gas guiding bodies have peripheral grooves into which the side edges of the box engage. In this manner the cylinders are fixed in a problem free manner, and, upon opening the box, the individual cylinders with the bodies can easily be removed for example in order to ensure ready insertion of the carded sliver. As shown here, on introducing the carded sliver, the cylinders 11.2 and 11.4 are first arranged in the lower part of the box. The carded sliver is then laid over these two cylinders, and the cylinders 11.2 and 11.4 are then likewise arranged in the lower part of the box 38 on top of the sliver so that the carded sliver adopts the desired snake-like course. Then the upper part of the box is set in place and fixed in its final position for example by clips. Thereafter the arrangement can be taken into operation.
FIGS. 4 and 5 show a perforated cylinder 50 which is drivably journalled and rotatable about the rotational axis R. The cylinder 50 is covered over by a suction hood 51 in the deflection region (indicated at 16 in FIG. 1) of the carded sliver 10 and indeed with a width B which is larger than the width (not shown) of the carded sliver 10. The suction hood 51 serves to suck away the aspiration air which, in accordance with the arrows that are shown, flows into the hollow cavity of the cylinder 50 and through the perforation holes 52 as well through the carded sliver 10 into the suction hood 51. An adjustable restriction flap 53 is provided in the suction hood 51 in order to regulate the quantity of air that is sucked off.
FIGS. 6 and 7 show a further perforated cylinder 55 which is arranged to be stationary during operation of the cleaning system.
Accordingly, the perforation holes 56 are provided only within the deflection regions of the carded sliver 10. The cylinder 55 is covered over in the same manner by the suction hood 51 already shown in FIGS. 4 and 5. The sucked-in air has the flow direction shown by the arrows.
Advantageously, the cylindrical surface of the perforated cylinder 55 is treated in the deflection zone of the carded sliver 10 by a surface treatment which results in a so called orange skin. The carded sliver slides better on a surface of this kind than on an untreated surface or surface which is too smooth.
FIG. 8 shows section-wise a variant of the perforations of FIG. 7 in which the perforation holes 56.1 are not radially arranged but rather, as shown in FIG. 8, have a direction inclined in the direction of movement of the carded sliver 10. The direction of movement is characterized by the arrow 57. Through the inclination of the perforation holes shown in FIG. 8, the air which flows in and which is illustrated by an arrow 58 has the task not only of releasing dust and contamination particles out of the carded sliver 10 but also of conveying the carded sliver in the conveying direction 57. The quantity of air, the air speed which is required, and the degree of perforation hole inclination required in particular situations can be determined experimentally in tests. Through this measure at least a smaller tension force has to be exerted on the carded sliver in order to convey the latter in the conveying direction 57.
FIG. 9 illustrates the use of either the perforated cylinder of FIGS. 4 and 5 and/or the perforated cylinder of FIGS. 6 and 7, in particular in combination with the perforation holes 56.1 of FIG. 8. It is evident from FIG. 9 that each cylinder is subject to the suction through the suction hood 51 which is associated with a vacuum source (not shown). The restriction flaps 53 make it possible to ensure a separate and/or joint control of the flows through the individual throughflow regions of the carded sliver.
Deflection rollers 59 can be provided in order to ensure the wrap of the carded sliver 10 before the first and after the last cylinders 50 and 55 respectively. These deflection rollers are advantageous rotatably and drivably journalled.
Furthermore, when using the cylinders 50 and 55 respectively, one advantageously proceeds in such a way that the first cylinder in the conveying direction 57 of the carded sliver 10 is a driven cylinder 50 and the following cylinder is a stationary cylinder 55 which is then followed by a driven cylinder 55 and finally by a stationary cylinder 50. Depending on the degree of wrapping and on the carded sliver, it is also possible to select a different sequence.
FIGS. 10 and 11 show a perforated cylinder 60 which is rotatably journalled by means of a ball bearing 62 in a stationary housing part 63 and which is driven by a belt 64. This kind of rotatable mounting and this type of drive can be used for all previously shown cylinders and for all the cylinders which will be described in the following.
In the interior of the perforated cylinder 60 there is provided a stationary perforated part 61 the perforation holes 65 of which match the perforation holes 66 of the rotatable cylinder 60. The stationary perforated part 61 is part of an air input element 67 which is either opened to the atmosphere in order to allow suction air to flow in or is connected with a pressure air source in order to blow pressure air through the perforation holes 65 and 66 respectively.
Through the use of stationary perforations 65 and a moving perforations 66, the air flow is repeatedly interrupted. Hence, a pulsing air flow exits from the perforations 66 to exert a beating effect on the carded sliver 10. Through this beating effect, the dust and contamination particles separate out better than with a continuous air stream.
FIG. 12 shows perforation holes 65.1 which are likewise inclined in the conveying direction, making use of the consideration of FIG. 8 in which the stationary perforation has an inclination in the conveying direction 57 of the fiber sliver 10. In this way the kinetic energy of the air stream in the perforation hole 65.1 can be used by means of the deflection into the radial direction of the perforation hole 66 for the drive of the rotatable cylinder 60. With such an arrangement, the belt drive 64 may be unnecessary in some applications. Again, the inclination of the perforation holes 65.1, the pressure of the flow and the quantity of air are factors to be determined in particular instances for appropriate tests. The values selected should be suitable for the purpose of driving the cylinder 60 but also for the purpose of cleaning the carded sliver 10.
FIG. 13 shows a variant of the use of the method. In this embodiment, the carded sliver 10 is moved in the conveying direction 57 between a perforated conveyor band 70 and a stationary perforated plate 71. A suction hood 72 is provided within the conveyor band 70 in such a way that air can flow through the carded sliver portion which lies above the perforated region of the plate 71 without an unacceptable proportion of leakage air likewise being sucked in through the suction hood 72. The suction hood 72 has suction openings 73 which open into a vacuum source, for example a suction fan.
By sucking the air through the perforated plate 71, an air layer arises between the carded sliver and the surface of the plate 71 so that the friction between this carded sliver 10 and the surface of the plate is strongly reduced by this air layer. Nevertheless, it can be of advantage to provide the surface of the perforated plate 71 with an orange skin as already described in conjunction with the apparatus of FIG. 6.
Moreover, the plate 71 can be provided with vibrators 74 with a high frequency and low stroke in order to achieve a beating effect on the carded sliver 10, which has already been described, and which facilitates the sucking off of the dust and contamination particles out of the carded sliver.
Also, as indicated with broken lines, the carded sliver can be guided at the entry of the conveyor band 70 around a curved edge 75 of the plate 71 so that, by guidance of the fiber band 10 around a rounded edge 75, a spreading of the fiber sliver 10 is caused which likewise leads to improved removal of the dust and contamination particles in conjunction with the suction effect.
At the entry of the conveyor band 70, the latter is provided with a drive roller 76. At its outlet, there is a perforated deflection roller 77. This perforated roller 77 serves the purpose of separating the fiber sliver 10 from the perforated conveyor band. For this purpose, the perforated deflection roller has a blowing channel 78 at its center which is connected via an inlet stub 79 with a source of pressurized air (not shown). The blowing channel covers over the perforations of the deflection roller 77 in which the fiber sliver 10 contacts the deflection roller 77.
For purposes analogous to those discussed in connection with FIGS. 8 and 12, the plate 71 may (as shown in FIG. 14) have perforation holes 80.1 which are inclined in the conveying direction 75 of the fiber sliver 10. This measure assists the conveying of the fiber sliver 10 on the plate 71.
Still other modifications of the invention will suggest themselves to persons skilled in the art. It is intended therefore that the foregoing disclosure of certain embodiments be considered as exemplary and that the scope of the invention be ascertained from the following claims.
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A method and an apparatus for cleaning a carded sliver during a movement of the latter in its longitudinal direction is disclosed. The carded sliver is guided over at least one guide surface having perforations which leads to spreading and loosening of the sliver, and an air flow is generated through the perforated guide surface in order to remove loose contaminations and also dirt and dust particles present in the loosened sliver. The air flow emerging from the carded sliver and carrying dust and dirt particles is preferably drawn off.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional application of Ser. No. 11/353,409, filed Feb. 14, 2006, which claimed benefit of provisional application Ser. No. 60/660,789, filed Mar. 11, 2005.
FIELD OF THE INVENTION
[0002] The present invention relates generally to a forklift attachment and method of using the same to lift a flexible dumpster, and particularly relates to a forklift lifting mechanism wherein the forks are adapted to rotatably pivot counterclockwise or clockwise to provide lateral compression forces against the flexible dumpsters for retrieval and disposal, which results in more efficient methods for disposing of waste.
BACKGROUND
[0003] Heavy steel dumpsters are the present state of the art in the waste disposal industry. A waste disposer calls the waste disposal company in advance of the waste generation event to request a large, rigid dumpster. As an initial step then the waste disposal company delivers the dumpster to the location using a large waste disposal vehicle. The vehicle has a means for unloading and loading these heavy steel dumpsters. However, these large bins and waste disposal vehicles frequently cause damage to the disposer's property during dumpster delivery and pickup, and the process of loading and unloading such large, steel bins can be quite hazardous.
[0004] Another disadvantage of using a large waste disposal vehicle for dumpster drop off and retrieval is its restricted dumpster placement range. For example, a large vehicle would not be able to place a dumpster behind the disposer's home or at a site inaccessible from a nearby street without causing extensive damage to the disposer's property. Most likely, and as is common, the large waste disposal vehicle would be forced to place the dumpster near a street or roadway to avoid damage to the disposer's land. This dumpster placement is inconvenient for disposers since they have to move their waste from the disposal site to the dumpster placement area, and this further imposes a burden on vehicles using the street. The present invention overcomes these and other disadvantages of the prior art by providing a method and apparatus pertaining to a lightweight flexible dumpster and modified forklift attachment.
SUMMARY OF THE INVENTION
[0005] The object of the present invention is to provide a forklift wherein its forks have a means for both vertical movement and rotatable/pivotable movement such that lateral compression forces can be applied to flexible dumpsters for retrieval and hauling.
[0006] Yet another object of the present invention is to provide a truck-mounted forklift and flexible dumpster system in order to prevent destruction of a disposer's property during dumpster retrieval.
[0007] Yet another advantage of the present system is to completely eliminate the step of requiring a dumpster to be dropped off by the waste disposal company.
[0008] Accordingly, what is provided is a forklift attachment generally comprising a pair of forks each having an upper portion and a lower portion. A fork plate has upper corners and lower corners and has defined therein a pair of upper bores and a pair of lower bores radially defined proximate to the lower corners. A mounting plate is connected to the fork plate to define an attachment interior. A pair of pivot pins each has a center axis normal to the fork plate and rotatably connects tops of the upper portions to the fork plate. A pair of lower bore pins each connect bottoms of the upper portions of the forks to the fork plate and are adapted to radially travel within one of the lower bores, about the center axis. A pair of upper bore pins connect the upper portions of the forks to the fork plate, with each upper bore pin adapted to radially travel within the upper bore about the center axis. A pair of actuators, each positioned behind the fork plate within the attachment interior have one end attached near one of the upper corners and another end attached to the upper bore pin, wherein upon actuation of the actuators, the upper bore pin can travel within the upper bore thereby rotating the forks about the center axis such that the forks can apply opposing lateral compression forces to a flexible dumpster.
[0009] Also, provided herein is a method for collecting waste using a modified truck-mounted forklift to allow for the utilization and hauling of a flexible dumpster, comprising the steps of, providing a flexible dumpster to a disposer, wherein the disposer places the flexible dumpster near the waste disposal site; unloading a truck-mounted forklift from a waste disposal vehicle; positioning the forklift within pickup range of the flexible dumpster; expanding pivotable forks in opposite directions of each other via at least one actuator; closing the pivotable forks via the actuator thereby engaging the forks with the side portions of the flexible dumpster, lifting the flexible dumpster utilizing the forklift's vertical movement, and loading the flexible dumpster onto the waste disposal vehicle, whereby large, rigid dumpsters do not have to be dropped off at the waste disposal site, and large trucks no longer have to be utilized.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 illustrates a side view of a conventional forklift with a side view of the forklift attachment.
[0011] FIG. 2 illustrates a front view of the forklift attachment with the pivotable forks of the forklift attachment in the closed position.
[0012] FIG. 3 illustrates a side view of the forklift and attachment being utilized to haul a flexible dumpster.
[0013] FIG. 4 illustrates a front view of the embodiment of FIG. 3 with the flexible dumpster.
[0014] FIG. 5 illustrates a top view of the forklift attachment.
[0015] FIG. 6 shows a detailed front view of the forklift attachment.
[0016] FIG. 7 shows a detailed side view of the forklift attachment.
[0017] FIG. 8 shows a cross-section side view of the forklift attachment.
[0018] FIG. 9 is a flow chart representing a method using the forklift and attachment to efficiently remove waste from a remote location.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0019] The invention will now be described in detail in relation to a preferred embodiment and implementation thereof which is exemplary in nature and descriptively specific as disclosed. As is customary, it will be understood that no limitation of the scope of the invention is thereby intended. The invention encompasses such alterations and further modifications in the illustrated apparatus and method, and such further applications of the principles of the invention illustrated herein, as would normally occur to persons skilled in the art to which the invention relates. “A” as used in the claims means one or more.
[0020] As illustrated then with reference to FIGS. 1-9 , a forklift attachment 10 is provided. This forklift attachment 10 is adapted for placement on a conventional forklift 1 . This invention contemplates both a forklift attachment 10 and a conventional or truck-mounted forklift made integral with the attachment 10 . It is also envisioned that the forklift can be mounted on a trailer for use. For purposes of this description, and not to limit the scope of the invention, the forklift attachment 10 will be referenced.
[0021] The forklift of attachment 10 includes a pair of forks 15 . The forks 15 are generally L-shaped and include an upper portion 17 and a lower portion 20 . The lower portions 20 extend generally perpendicularly from the upper portions 17 and parallel to the ground, but they may also be slightly angled in either direction relative to the upper portions 17 or rotationally with respect to the ground. For example, the upper portions 17 may slope toward each other, thus forks 15 can be angled (not shown) to provide for improved pickup of a flexible dumpster and further to prevent the forks 15 from puncturing the flexible dumpster.
[0022] The forks 15 are mounted to a generally rectangular, fork plate 50 having upper corners 73 and lower corners 73 a . Within the fork plate 50 , a pair of slot-like upper bores 41 and a pair of lower bores 42 are defined radially therein about a center point of rotation for the forks 15 , proximate to the lower corners 73 a . This center point of rotation is formed using a pair of pivot pins 25 . The pivot pin 25 has a center axis normal to the fork plate 50 , rotatably connecting tops 15 a of the upper portions 17 of the forks 15 to the fork plate 50 . The pivot pin 25 is further secured using pin hex nut 76 to the back of the mounting plate 60 . As such, the forks 15 are adapted to rotate or pivot clockwise or counterclockwise on the fork plate 50 .
[0023] A pair of lower bore pins 43 connect bottoms 15 b of the upper portions 17 of the forks 15 to the fork plate 50 , for example by using a nut and screw or bolt fastened to the fork 15 through the fork plate 50 . A similar type of fastening means may also be used which connects the fork 15 all the way to the mounting plate 60 , provided there is an identically shaped lower bore defined within the mounting plate aligned with the lower bore 42 of the fork plate 50 . The lower bore pins 43 are adapted to radially travel within the lower bores 42 , about the center axis defined by the pivot pin 25 while holding the fork 15 in place. With this configuration then, the forks 15 can be kept aligned with the fork plate 50 upon rotation, with the limits of rotation or pivoting of the forks 15 fixed by the size of the lower bore 42 .
[0024] A pair of upper bore pins 40 further connect the upper portions 17 of the forks 15 to the fork plate 50 . Each upper bore pin 40 is preferably longer than the lower bore pin 43 , situated against or directly to the mounting plate 60 so as to retain both the fork 15 and an actuator 35 in place, as further described. In one embodiment, each upper bore pin 40 will ride against a face plate 102 mounted on the mounting plate having a groove defined identically to each upper bore 41 . The upper bore pin 40 may also travel within an identically sized bore of the mounting plate 60 if directly attached to the mounting plate 60 . Each upper bore pin 40 is adapted to radially travel within each upper bore 41 , about the center axis of the pivot pin 25 . As shown, the upper bore 41 has a radial length smaller than the lower bore 42 since the upper bore 41 is positioned closer to the pivot pin 25 and thus the point of rotation. Some type of lubricant may be placed within each bore and/or on each pin to reduce friction and enable better wear.
[0025] A mounting plate 60 generally of similar size to the fork plate 50 is connected to the fork plate 50 by being bolted thereto using one or more shoulder bolts 101 and/or by using a support plate 90 and support plate tab 91 . Specifically, a support plate tab 91 is perpendicularly formed on the mounting plate 60 . Then, for added rigidity, the support plate 90 is perpendicularly situated over the support plate tab 91 with one edge welded to the mounting plate 60 and the other edge welded to the fork plate 50 . With this configuration, an attachment interior 50 b is defined between the mounting plate 60 and fork plate 50 .
[0026] Each fork 15 is rotated by providing an actuator 35 positioned behind the fork plate 50 within the attachment interior 50 b . The term actuator here covers any type of actuation, including but not limited to, mechanical, hydraulic, air or the like. The actuators 35 may also vary slightly in location. Basically, the actuator 35 has one end positioned near one of the upper corners 73 of the fork plate 50 (and similar sized, opposing corner of the mounting plate 60 ). The other end of the actuator 35 is connected to the upper bore pin 40 , wherein upon actuation of the actuator 35 , the upper bore pin 40 is drawn upwards and forced to travel along a path defined by the upper bore 41 , thereby rotating or pivoting each fork 15 .
[0027] More specifically and in one embodiment for the actuation means, the actuator 35 comprises a cylinder housing 71 having a housing top 71 a and housing bottom 71 b , wherein the housing top 71 a is mounted on the shoulder bolt 101 behind and near the upper corner 73 of the fork plate 50 . A hydraulic or pneumatic cylinder 35 a is then situated within the cylinder housing 71 . A shaft 70 movable by or within cylinder 35 a has a shaft eye 82 formed on its lower end distal from the cylinder 35 a . The shaft eye 82 allows the shaft 70 and thus the cylinder 35 a to be connected to the upper bore pin 40 . A longitudinal sleeve 92 may assist in retaining shaft eye 82 in place on upper bore pin 40 . Thus, upon actuation of actuator 35 , the upper bore pin 40 travels within the upper bore 41 , thereby rotating the forks 15 about the center axis/pivot pin 25 such that the forks 15 can apply opposing lateral compression forces to, for example, a flexible dumpster 2 .
[0028] Now referring to the method disclosed by the present invention and with reference to FIGS. 3 , 4 , and 9 specifically, with the discovery of the forklift attachment 10 described above, a method of utilizing a forklift. 1 in an improved system of flexible dumpster 2 retrieval is further defined. This method of collecting waste first involves the distribution 91 or sale of lightweight flexible dumpsters 2 to the disposer in a retail-type setting. It is envisioned that hardware and construction supply stores in particular will sell these flexible dumpsters 2 . The dumpsters will preferably be packaged in a flat vacuum sealed package. The flexible dumpsters, also known in the art as “bulk bags,” are similar to the kind sold by the Alabama Bag Company. These products can hold a great deal of waste material because of their tightly woven fabric and strong tear-resistance. The flexible dumpsters can be disposable or alternatively be recyclable.
[0029] The flexible dumpster 2 has many advantages over the prior art conventional steel dumpster. For one, the flexible dumpster 2 does not require delivery to the disposer's site. As discussed above, the disposer will simply purchase as many flexible dumpsters as needed for the disposal. If the number of bags needed for a project is over-estimated, the surplus dumpsters can be returned to the retail store. Further, contractors or other waste disposers can easily place a flexible dumpster in their vehicle or toolbox for use when necessary. Secondly, the flexible dumpster can be placed at any location suitable for pickup with the truck-mounted forklift 1 with the forklift attachment 10 . Thus, the disposer could for example place the dumpster 2 outside of a window of a room where construction is being performed. Thus, the disposer, instead of having to take the waste material out near the street where a conventional dumpster would be located, can instead throw the waste material out the window into the flexible dumpster 2 . Thirdly, the flexible dumpster 2 is very light-weight and this greatly reduces the damage done to the disposer's property caused by the weight of the conventional dumpsters. The traditional step of delivering and dropping off large, bulky dumpsters is eliminated 90 . This will increase business efficiency while decreasing expenses for waste hauling companies since the flexible dumpsters need only be picked up for disposal with no steel dumpster delivery step being required 90 .
[0030] During waste loading as the flexible dumpster 2 is utilized 92 , the disposer would work the sides of the flexible dumpster 2 upward relative to the amount of waste material placed therein. The flexible dumpster 2 would generally be filled to full capacity.
[0031] After the flexible dumpster 2 is filled with waste material, the disposer would then contact a waste disposal company for pickup 93 . The waste disposal company would then dispatch a waste removal vehicle 94 loaded with a truck-mounted forklift and forklift attachment 95 to retrieve the flexible dumpster or dumpsters. When the driver of the waste removal vehicle arrives at the disposal site, the driver would climb into the truck-mounted forklift and lower it from the truck. The driver would then drive the forklift 1 to the placement site of the filled flexible dumpster 2 as the use of the large hauling truck is bypassed 98 .
[0032] During the vehicle and attachment utilization step 96 , after arrival at the placement site, the driver causes the forks 15 to move in a direction opposite each other into their open position. Then the driver assures that the truck-mounted forklift 1 is in proper position to lift the flexible dumpster. Next, the driver causes the pivotable forks 15 to return to a partially closed position, thereby rotationally engaging 97 the flexible dumpster 2 with the forks 15 . The flexible dumpster is then carried back to the waste disposal vehicle and loaded via the truck-mounted forklift. The driver then reattaches the truck-mounted forklift to the truck and either picks up additional dumpsters or drives to the waste landfill for disposal. At the landfill, the flexible dumpster is unloaded either utilizing the truck-mounted forklift 10 or alternatively the truck bed will dump the flexible dumpsters into the landfill.
[0033] The entire flexible dumpster can then be disposed of at the landfill 99 . Alternatively, the flexible dumpsters can also be recyclable. In this situation, the contents of each dumpster would be individually dumped into the landfill.
[0034] This invention can be utilized on a conventional forklift as well as a truck-mounted forklift. Further, as explained above, the forklift attachment can be integral to a conventional or truck-mounted forklift and not manufactured as an attachment. Nothing in this description is meant to limit the forklift attachment's use to only a truck-mounted forklift. For example, the forklift attachment 10 would be useful in the industrial setting where a company would have a conventional forklift 1 on site. The forklift attachment 10 would perform in the same manner as explained above with reference to the truck-mounted forklift. However, in an industrial setting or other setting where a conventional forklift 1 is on site, the waste disposal vehicle would not be required to transport the forklift to the pick up site. In this industrial setting the forklift attachment 10 could be used to move products in addition to waste.
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A method for collecting waste, wherein a disposer places a flexible dumpster near a waste disposal site whereby a truck-mounted forklift can be utilized to engage forks with the side portions of the flexible dumpster for loading and disposal. Accordingly, large dumpsters do not have to dropped off at the waste disposal site and large trucks no longer have to be utilized.
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BACKGROUND OF THE INVENTION
The present invention relates to a tension controlling device for the connection of members held in tension.
Many devices today employ a tension member to connect a flexible member to a relatively fixed member. One example is found in automatic garage door operators which use a flexible member such as a belt or chain to raise and lower the garage door. The flexible member is secured to a trolley which is linearly moved by an electrical motor to raise and lower the door. A tensioning device which includes a spring to maintain substantially constant tension in the flexible member and to counter the shocks of starting and stopping the door movement is used to connect the flexible member and the trolley.
One such device is described in U.S. Pat. No. 5,297,782 to Dombrowski et al. and includes a threaded shaft connecting a flexible member through an aperture in a trolley. A snubber unit is screwed onto the threaded shaft until the tension in the flexible member is approximately correct as judged by an assembler. At this time, a split ring keeper is removed from the snubber unit, which releases a spring to push against the trolley, finally adjusting the tension.
The Dombrowski et al. arrangement has performed well, however, the final tensioning of the flexible member is the result of adjusting the tension without the added spring tension, then later adjusting the tension with the added spring tension. Further, the removal of the split ring has been found difficult, particularly by home assemblers of a garage door system. Lastly, the final tension of the flexible member, which is important to the operation of the system, is left to the eye of the assembler which may vary from case to case.
A need exists for an improved apparatus for connection and tension adjustment between a first member and a flexible member which is easy to install and which controls the tension of the connection.
SUMMARY OF THE INVENTION
The need is met by tensioning apparatus in accordance with the present invention in which a threaded member is attached between the flexible member on one side of a wall and the tensioning apparatus on the other side. The tensioning apparatus includes right-handed mating threads so that clockwise rotation about an axis of the tensioning apparatus increases tension in the flexible member. The tensioning apparatus is rotated by a retaining member which is left-hand threaded to the tensioning apparatus about the axis of rotation. The retaining member is frictionally engaged with the tensioning apparatus by a spring which is compressed by tension in the flexible member. As tension in the flexible member increases, the amount of frictional engagement force decreases and the tensioning apparatus is rotated clockwise by means of the retaining means. When the tension in the flexible member becomes a predetermined amount, the frictional forces holding the retainer fixed to the tensioning apparatus are too small to hold the retaining means which breaks loose and rotates free and may be removed from the tensioning apparatus by continued clockwise rotation. It should be mentioned that the left-handed and right-handed threads can be switched so that the retaining member is connected by right-hand threads and the tensioning apparatus is connected to the flexible member by left-hand threads. What is needed is that the retaining member is connected to the tensioning apparatus by threads of one sense while the tensioning apparatus increases tension in the flexible member by means of threads of the opposite sense.
Tensioning apparatus in accordance with an embodiment of the invention comprises a base member disposed against one side of a wall which may be a part of a door or other barrier movement trolley. A retaining member is connected to the base by threads of a first sense, e.g., left-handed and a threaded member having threads of a second sense opposite to the first sense extends through the wall and connects the flexible member to the tensioning apparatus so that rotation of the tensioning apparatus in a first direction increases tension in the flexible member. A spring is disposed between the base and an enlarged adjunct of the threaded member to force the enlarged adjunct into frictional engagement with the retaining member. The above is constructed so that when the retaining member is rotated in the first direction, tension will increase in the flexible member and the frictional force between the enlarged portion and the retaining member will decrease. When the frictional force diminishes to a predetermined amount, the retaining member will "break loose" and rotate freely from the tensioning apparatus. By properly selecting the components of the tensioning apparatus, the final tension in the flexible member can be accurately predetermined.
In accordance with one embodiment of the invention, the threaded member is fixed to the flexible member and connects to a threaded tension adjusting unit having a threaded bore and the enlarged shoulder.
In accordance with another embodiment, the threaded member and enlarged portion may be an integrated unit which attaches to a threaded bore attached to the flexible member. The retaining member may be in the shape of a threaded cylindrical plug which screws into side walls attached to the base of the tensioning apparatus or it may be a threaded cap which screws onto threads around the side wall of the tensioning apparatus.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a fragmentary elevational view of a trolley drive system for a garage door operator;
FIG. 2 is a cross-sectional view of a tensioning apparatus in accordance with the invention;
FIGS. 3, 4 and 5 are fragmentary perspective views showing installation of the tensioning apparatus;
FIG. 6 is an exploded view of the tensioning apparatus of FIG. 2;
FIG. 7 shows an alternative embodiment of the connection between the tensioning apparatus and flexible member; and
FIG. 8 is a cross-sectional view of an alternative embodiment of the tensioning apparatus.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The present invention is described herein as apparatus for connecting a flexible member, e.g. chain 12, to a trolley 26 of a garage door or other barrier opener. The garage door opener assembly is generally indicated at 10 in FIG. 1. A double-ended drive chain 12 is wrapped around a support rail 14 which extends between the drive motor of the garage door opener system (not shown) and the wall to which the garage door is mounted. The chain 12 has a first end 16 which is pinned at 18 to a threaded shaft 20. Chain 12 also includes a second end 22, pinned at 24 to trolley 26. The trolley 26 is of a conventional design, and includes a guide 30 which rides on a flange 32 of support rail 14. The support rail 14 is of a generally inverted T-shaped cross section. Trolley 26 further includes a mounting eye 36 for connection to a garage door, to move the garage door back and forth in a direction of double-headed arrow 40.
The drive chain 12 is wrapped about a gear sprocket located to the left of FIG. 1. The gear sprocket is driven in opposite directions, so as to move trolley 26 in the direction of double-headed arrow 40. During opening of the garage door, the trolley of FIG. 1 moves to the left and the direction of movement is reversed for a door closing operation. Thus, during a door closing operation, when the trolley is moved to the right-hand direction in FIG. 1, tension at the end 16 of the drive chain is relaxed and end 16 may even be placed in a slight compression, during some operating conditions of the garage door and garage door opener system. The free end of the threaded shaft 20 is inserted through an opening 44 (FIG. 3) in a mounting wall 46 of trolley 26 and is mounted to wall 46 with a tensioning apparatus 50 according to the present invention.
FIG. 2 shows a cross sectional view of tensioning apparatus 50 which includes a tensioning nut 101 having an internal right-hand thread 103 for attachment to the right-hand threaded member 20 of chain 12. Tensioning apparatus 50 includes a base 105 having an inner surface 106, an outer surface 104 and a central aperture 107 for freely passing the threaded member to the tensioning nut 101. In the present embodiment, the base 105 includes a cylindrical side wall 109. The top of side wall 109 includes internal left-hand threads 111 for the engagement of a retainer nut 115. Retainer nut 115 includes a cylindrical portion having left-hand threads 119 therearound for engagement with threads 111 of the side wall 109 and at the top a hexagonal portion 113 for standard wrench engagement. The retainer nut 115 also includes a central aperture 121 through which the threaded member 20 can freely pass. A spring 123 surrounds the tensioning nut 101 and is disposed against the inner surface 106 of base member 105. The tensioning nut 101 includes an enlarged portion or shoulder 125 against which the spring 123 contacts. As shown, the retaining nut 115, tension nut 101 are substantially coaxial when assembled. In FIG. 2, the spring 123 is compressed between shoulder 125 and base 105. The threaded bore 103, apertures 107 and 121 and the retaining nut 115 are all disposed to rotate about a common axis.
FIG. 6 is an exploded side view of the tensioning apparatus 50 and clearly shows that spring 123, in an uncompressed state, is longer than the cylindrical side walls of the tensioning nut 101. Tensioning apparatus 50 is assembled by inserting spring 123 into the cylinder 109, inserting the tensioning nut 101 into the center of the spring 123 compressing the spring and connecting the retainer nut 115 by means of the left-hand threads 119, 111. The side wall 109 is held from rotation and the retainer nut 115 is screwed into the side wall threads to compress spring 123. The amount of spring compression determines the static friction between the upper surface 126 of shoulder 125 and the lower surface 128 of retainer nut 115 and is controlled by the length of the spring 123, its spring constant and the depth to which nut 115 is screwed.
During assembly of the garage door opener system, the chain and support rail 14 are assembled and the threaded member is inserted through aperture 44 in wall 46 of the trolley 26. The tensioning apparatus 50 is then slid over the threaded shaft 20 until the shaft is engaged by right-hand threads 103 of tensioning nut 101 at which time tensioning apparatus 50 is rotated clockwise as shown at 88 (FIG. 4) to draw it onto threaded member 20. This may initially be done by manually rotating the side wall 109. When the base 105 contacts the wall 46, further tightening of tensioning apparatus 50 is performed using an appropriate wrench on nut 113.
It will be remembered that retainer nut 115 is left-hand threaded so that clockwise rotation of nut 113 will force it in a direction of rotation which would loosen the retainer nut 115 if the retainer nut were free to rotate. The friction between tensioning nut 101 and retainer nut 115, however, is initially strong enough to keep retainer nut 115 from rotating in its threads 111, 119. Instead, the entire assembly 50 is rotated onto threaded shaft 20. As threaded shaft 20 is drawn into tensioning nut 101 it exerts a downward (FIG. 2) force on nut 101 causing compression of spring 123 and a lessening of normal forces of friction between the shoulder 125 and retainer nut 115. At a predetermined amount of compression of spring 123, i.e., at a predetermined reduction of friction between tensioning nut 101 and retainer nut 115, the rotation of retainer nut 115 will overcome the frictional forces and the retainer nut will begin to rotate. Due to the left-hand thread of the retainer nut 115, it will be removed by continuing clockwise rotation. Careful design of the tensioning apparatus results in removal of the retainer nut 115 at a predetermined amount of tension in threaded member 20 and the claim 12.
During tightening, the static frictional force between the retainer nut 115 and the tensioning nut 101 must exceed the rotational forces between the wall 46 and base 105 and the frictional forces of the threaded shaft 20 and tensioning nut 101 until proper tension in the threaded member is achieved. In a system where:
F sp =force of spring
F b =force in threaded member (flexible member)
μ t =coefficient of friction between tension nut and retainer nut
μ tt =coefficient of friction between threaded member and tension nut
μ n =coefficient of friction between retainer nut and casing
r t =effective radius of tension nut and retainer nut contact
r tt =effective radius of threaded member and tension nut threads
r n =effective radius of threads of retainer nut
then the tension in the flexible member F b at breakaway of retainer nut can be calculated from:
(F.sub.b)(μ.sub.tt)(r.sub.tt)+(F.sub.b)(μ.sub.t)(r.sub.t)=(F.sub.sp -F.sub.b)μ.sub.n r.sub.n
In the preceding embodiment, the retainer nut 115 is in the form of a cylindrical plug which fills an open end of the cylindrical side walls 109 of the tensioning apparatus 50. In an alternative embodiment (FIG. 8), the retainer nut could be in the form of a cap 116 for the tensioning apparatus having left-hand internal threads 114 which mate with left-hand threads about the exterior of side wall 109. As in the preceding example, friction between tensioning nut 101 and retaining cap 116 will cause rotation of the entire apparatus 50 until the spring 123 compresses to diminish the friction to a predetermined point, at which the cap 116 rotates free from the apparatus.
Also, the preceding embodiments disclose a tension nut 101 having internal threads. An alternative embodiment is shown in FIG. 7 in which the exterior of a replacement tensioning unit 102 (FIG. 7) is substituted for the tension nut 101. The tensioning unit comprises a first portion 92 having a similar exterior shape to tension nut 101 and a threaded member 21 fixed, not threaded, thereto. Threaded member 21 has right-hand threads and extends through base 105 and wall 46 to mate with an internally right-hand threaded receiver (not shown) attached to the chain 12.
In the present description the retaining nut 115 is attached to the side wall/base by left-hand threads and the threaded member increases tension in the flexible member by right-handed threads. The sense of the two threaded connections can be exchanged and the result of operation will be the same as above described. That is, the retainer nut 115 could be right hand threaded and tension nut 101 could be left-hand threaded. The only difference in operation would be the counterclockwise rotation needed for increasing tension in the flexible member. As described herein, the retaining nut should be attached to the tensioning apparatus by threads of a first sense while the tensioning nut should increase tension in the threaded member by threads of a second sense opposite to the first sense.
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A tensioning device is connected to a flexible drive member by a right-hand threaded member on the drive member, which projects through an opening in the wall of a trolley. The threaded member is threaded onto a tensioning nut which is biased by a spring which mounts the nut in the base of the tensioning device. A retainer nut having left-hand threads is in frictional engagement with an enlarged portion of the tensioning nut, such that turning of the retention nut tightens the tensioning device onto the threaded member until the frictional force of the engagement between the enlarged portion of the tensioning nut and retainer nut is reduced to a predetermined amount.
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FIELD OF THE INVENTION
[0001] The invention relates to control of impulse-generated (sometimes termed shock-generated) vibration for diagnostic testing and/or controlled fragmentation. Applications include vibration testing of geological strata or mechanical structures to characterize how inherent strengths and weaknesses affect their use. In the oil and gas industry, information from down-hole equipment develops control data which guides well completion. Particularly demanding applications include combining impulse-generated swept-frequency stimulation vibration with cyclically-varying hydraulic pressure (herein: adaptive stimulation) on intervals along horizontal wellbores in ultralow-permeability (unconventional) formations. The invention is related to U.S. Pat. Nos. 8,939,200, 8,944,409, 9,027,636, 9,080,690, and 9,169,707. The application is a continuation-in-part of co-pending U.S. patent application Ser. No. 14/919,848 (filed 22 Oct. 2015), and is related to co-pending U.S. patent application Ser. No. 15/645,430 (filed 10 Jul. 2017).
INTRODUCTION
[0002] New designs described herein incorporate innovative applications of well-known technical principles for improved data collection to support design improvements and optimize stimulation system performance. Adverse and beneficial aspects of the technical principles are represented in relationships between mechanical shocks and their broad-spectrum impulse-generated vibration. For example, adverse aspects of these relationships are strikingly manifest in the troubling fluid-end failure rates of even the most modern conventional high-pressure well-stimulation pumps (termed frac pumps herein). On the other hand, beneficial aspects can be employed both to increase frac pump reliability and to enhance well productivity through more efficient and localized adaptive stimulation of geologic material surrounding a wellbore. That is, well completion is informed by analysis of backscatter vibration data from the stimulated material.
[0003] Note that alternative configurations of adaptive stimulators of the present invention may be placed in selected wellbores for purposes other than well completion (e.g., to test for local seismic activity using timed bursts of diagnostic stimulation vibration). And a well system undergoing either test or completion may be preloaded by its hydraulic head and/or supplemental pump pressurization. Performance testing is yet another application of adaptive stimulators, wherein they may be hydraulically coupled to structures such as bridges or railroad track beds to detect fatigue cracking, settling, corrosion and other phenomena likely to affect performance. As in the case of well completion applications and seismic studies, static and/or dynamic preloading may be desirable in performance testing to more completely characterize the structures tested.
[0004] Creation of adaptive stimulation for any purpose begins with broad-spectrum impulse-generated vibration (i.e., vibration bursts simultaneously comprising a plurality of vibration frequencies). Such bursts are sometimes termed shock-generated vibration, and they are commonly seen in oil field operations to be either beneficial or detrimental. For a detrimental example, consider the mechanical shock of valve closure under pressure in a high-pressure pump fluid end. The shock creates a plurality of vibration frequencies that can lead to excitation of destructive vibration resonances in the fluid end or the entire frac pump. These excited resonances predispose various pump parts to fatigue-related cracking and ultimate failure. A variety of designs shown and described in the following materials explain how such damaging vibration resonances can be controlled (e.g., suppressed) using a hierarchy of tunable systems, tunable subsystems, tunable components and design elements. Controlling destructive resonance excitation vibration, in turn, limits vibration-induced cracking.
[0005] Specific examples are cited in the following paragraphs to illustrate how frac pump reliability improvements have evolved from a better understanding of causes and effects of shock and vibration in fluid ends. First, remarkably strong and repetitive energy impulses (associated with mechanical shocks) commonly originate in frac pump fluid end valves. Second, both the bandwidth and amplitude of impulse-generated vibration produced by repetitive high-pressure closure of conventional fluid end check valves can be reduced through innovative design changes. Third, without such design changes, fatigue-related damage (due to resonance excitation by impulse-generated vibration) is exacerbated and frac pumps are predisposed to fluid end failures (an increasingly common problem).
[0006] But resonance vibration excitation shouldn't always be limited in well stimulation systems; sometimes it should be enhanced! In the present invention, broad-spectrum impulse-generated vibration originates in adaptive down-hole hydraulic stimulators, being transmitted via each stimulator's fluid interface to surrounding geologic material. Transmitted vibration can be tailored, and tailoring is initiated by alternately up-shifting and down-shifting (i.e., cyclically shifting) the power spectral densities (PSD's) of the vibration frequency spectra in a predictable manner. Cyclical PSD shifting produces vibration frequency sweeps originating in the predictably-varying PSD's. The frequency sweeps thus embedded in adaptive stimulation vibration can facilitate maximization of stimulation efficiency through analysis of backscatter vibration originating in stimulated (e.g., fractured) geologic material.
[0007] The simultaneous presence of cyclically-varying down-hole hydraulic pressures in predetermined phase relationships (e.g., in-phase) with cyclically-shifted PSD's predictably increases rock fracturing, with associated fragmentation, throughout a range of rock particle sizes at varying distances from a wellbore. The varying distances are functions of both the cyclically-varying down-hole hydraulic pressures and the inherent dynamic response of the stimulated geologic material.
[0008] Summarizing, adaptive stimulation systems as described herein effectively address frac pump fluid-end fatigue failures by (1) altering check valve closure mechanics to reduce mechanical shock; and/or (2) down-shifting the PSD's of valve-generated (i.e., impulse-generated) vibration spectra to reduce the deleterious effects of resonance excitation. Further, adaptive stimulation systems modify, electively in phase relation (e.g., in-phase), cyclically-varying down-hole hydraulic pressures and cyclically shifted stimulation vibration PSD's to improve stimulation efficiency. *** Thus, adaptive stimulation systems can tailor frequency sweeps of impulse-generated vibration to preferentially cause resonance vibration excitation (i.e., stimulation) of geologic material at varying distances from a wellbore. Backscatter vibration emanating from the stimulated geologic material supports dynamic analysis of widely-variable unconventional geologic formations. Further, such backscatter vibration can inform adaptive modification of the swept-frequency down-hole stimulation vibration and/or the cyclically-varying down-hole hydraulic pressures. ***
[0009] By combining cyclically-varying down-hole hydraulic pressures in predetermined phase relation with alternating up-and-down shifts of stimulation vibration PSD (i.e., cyclical PSD shifts), adaptive well stimulation can accomplish four complementary functions: (1) to fracture geologic material at varying distances from a wellbore (thereby opening channels in it); (2) to prop the channels open with rock fragments that are self-generated in situ by stimulation vibration that is tailored during the fracturing process; (3) to characterize the stimulated geologic material as to the degree of stimulation achieved (e.g., the quantitative beneficial results of actual geologic fracture and particle fragmentation) in comparison with that desired; and (4) to adaptively modify cyclically-varying down-hole hydraulic pressures and/or cyclically-shifted PSD's of impulse-generated swept-frequency stimulation vibration to improve stimulation efficiency.
[0010] To optimize these complementary well-stimulation functions, the extent of geologic fracturing is periodically assessed in near-real time. Assessment begins with detection of band-limited backscatter vibration corresponding to the frequency sweeps of stimulation vibration. Such backscatter vibration emanates from the stimulated geologic fragments as they are formed by fracture, and backscatter assessment analysis proceeds continuously. In particular, signals representing the backscatter vibration are processed in programmable controllers to produce feedback data and control signals for one or more tunable down-hole hydraulic stimulators (i.e., timed stimulator signals) and the frac pump(s) providing cyclically-varying down-hole hydraulic pressure (i.e., timed pressure signals). Note that signal processing and analysis in programmable controllers is carried out using empirically-derived software algorithms (broadly termed herein: frac diagnostics).
[0011] The controller, in turn, ensures that swept-frequency stimulation vibration arises in part from cyclical up-shifts and down-shifts of PSD achieved by electromechanical adjustment of rebound cycle time associated with hammer strikes in a shock wave generator. And swept-frequency stimulation vibration also arises in part from cyclical up-shifts and down-shifts of PSD achieved by magnetostrictive adjustment of shock-wave generator fluid interface resonant frequencies. The latter adjustment is achieved by step-wise changing of the steady-state flux density of one or more longitudinal magnetic fields applied to one or more magnetostrictive amorphous ferromagnetic alloy disc-shaped thin members comprising a vibration generator fluid interface. See, e.g., U.S. Pat. No. 8,093,869, incorporated by reference.
[0012] Among other remarkable properties of the above magnetostrictive amorphous ferromagnetic alloy disc-shaped thin members (comprising, e.g., the amorphous ferromagnetic alloy Metglas 2605SC), the disc-shaped thin members can be configured to resonate at a predetermined frequency and/or to convert applied mechanical energy to vibration electrical signals (as in, e.g., a vibration detector). See, e.g., U.S. Patent Application Publication 2005/0242955.
[0013] Magnetostrictive materials can also be configured as a magnetostrictive lens operable in response to a coil-generated magnetic field (see, e.g., U.S. Pat. No. 5,458,120, incorporated by reference). Metglas 2605SC exhibits a change up to about 80% of effective Young's Modulus (i.e., effective elastic modulus) with magnetization to saturation in bulk. Young's Modulus is an indicator of stiffness, and changes in stiffness can thus be used to tune the resonance frequency of a shock wave generator fluid interface. See, e.g., U.S. Pat. Nos. 5,381,068 and 9,339,284 incorporated by reference.
[0014] In addition to feedback data from the above signal processing, supplemental geologic data may be obtained from frac diagnostics using signals from conventional well-logging apparatus and/or measurement-while-drilling (MWD) tools. Further, data-science techniques applied to studies of differences between swept-frequency stimulation vibration and corresponding band-limited backscatter vibration can reveal structural information on stimulated geologic material that is both highly-desirable and otherwise unobtainable.
[0015] Note particularly that use of swept-frequency impulse-generated stimulation vibration confers substantial advantages in characterizing geologic material adjacent to the wellbore. First, the overall broad spectrum of applied vibration ensures that a broad range of rock particle sizes will resonate (and hence tend to fragment) with each burst of stimulation vibration energy. Backscatter vibration accurately reflects the extent of this desired fragmentation. Second, due in part to the electro-mechanical mode of stimulation vibration generation described herein, the bandwidth, phase and amplitude of vibration frequency sweeps will vary slightly from burst-to-burst. Inherently then, the likelihood of missing critical geologic resonance vibration frequencies within successive frequency sweeps of stimulation vibration is reduced. Third, the down-hole stimulation vibration generators described herein can be tailored: e.g., their output PSD's (and thus their frequency sweeps) can be adjusted via closed-loop control systems. Stimulation energy may therefore be electively stepwise concentrated in progressively higher frequency ranges as stimulation-induced geologic fragmentation progresses through a range from large pieces to smaller (proppant-sized) fragments. And Fourth, the substantially real-time concentration of stimulation energy in frequency ranges likely to induce desired degrees of geologic fragmentation results in higher efficiency. Energy thus applied minimizes unproductive heat loss because the relative amount of stimulation energy transmitted in less productive frequency ranges is reduced.
[0016] The above-described advantages of tailored stimulation stem in part from the fact that backscatter vibration, processed via frac diagnostics to yield feedback data, provides geologic information that is otherwise unobtainable. Functions of feedback data, in the form of control signals from programmable controllers, allow tailoring of the process of closed-loop geologic stimulation to the requirements of individual (unconventional) formations. Such closed-loop stimulation control incorporates feedback of a portion of the controlled-system output (i.e., backscatter vibration from stimulated geologic material) to the controlled-system input (i.e., adaptive stimulation vibration generated via mechanical shock). In other words, backscatter vibration data are used to alter the mechanical shocks themselves, thereby fine-tuning stimulation vibration as needed for quick convergence on optimal stimulation vibration frequency end-points.
[0017] Closed-loop control of mechanical shocks in a vibration generator as described herein implies control of the kinetic energy impulses corresponding to a moving hammer (or mass) element striking, and rebounding from, a fluid interface having an adjustable effective elastic modulus. This apparatus is termed herein a tunable down-hole hydraulic stimulator. At least a portion of the initial kinetic energy for each hammer strike is converted to broad-spectrum impulse-generated vibration energy through vibration of the stimulator's fluid interface. So with each hammer strike and rebound, the vibration spectrum's PSD can be detected and adjusted as desired under closed-loop control in near-real time.
[0018] Closed-loop PSD control for tunable down-hole hydraulic stimulators means that transmitted vibration spectra from a tunable hydraulic stimulation vibration generator are tuned at their source (e.g., by altering the rebound cycle time for each hammer element strike and/or stepwise alteration of the fluid interface's effective elastic modulus). Such tuning effectively shapes a transmitted vibration spectrum's PSD to concentrate stimulation vibration power in predetermined frequency ranges. The predetermined frequency ranges for any stage of stimulation are (1) ranges that maximize transmission of vibration resonance excitation power to the adjacent geologic materials and/or (2) ranges that facilitate characterization of the geologic materials through analysis of backscatter vibration. As stimulation proceeds, each predetermined frequency range necessarily changes (through the mechanism of PSD shifts), thereby generating frequency sweeps as described herein.
[0019] The stimulated geologic materials themselves, after a short time delay, report their actual absorption of tailored stimulation vibration energy (i.e., resonance excitation) in the form of backscatter vibration. Feedback data are then derived from the backscatter vibration. Calculated control signals (which are based on the feedback data) close the loop in closed-loop impulse-generated vibration control. Like the feedback data, control signals are also calculated using a programmable controller running frac diagnostic software. And the control signals are then applied (e.g., via feedback control link) to one or more tunable hydraulic vibration generators and/or frac pumps to optimize down-hole stimulation in near-real time.
[0020] Note that evaluation of backscatter vibration data detected via one or more down-hole stimulators may optionally be enhanced in light of, e.g., corresponding down-hole temperature and/or hydraulic pressure data. These parameters, electively combined with associated well-logging data, may be sensed at one or more down-hole stimulators. And enhanced evaluation may then be carried out, e.g., via frac diagnostics in a programmable controller for the relevant tunable down-hole stimulation system.
[0021] To acquire the benefits of backscatter vibration data as described above, tunable down-hole stimulators must transmit sweeps of impulse-generated stimulation vibration to geologic materials adjacent to their wellbore stages or location(s). Geologic access is via, e.g., casing perforations and/or slots (i.e., ports or access openings). Since optimal resonance excitation frequencies necessarily change as stimulation progresses, closed-loop control in the stimulator(s) causes the PSD of stimulation vibration energy to be correspondingly shifted in near-real time to optimize stimulation of, and thus generate the corresponding backscatter vibration from, individual producing zones or stages within a wellbore. (See, e.g., U.S. patent application number 2014/0041876 A1, incorporated by reference). *** Optimization thus means: (1) more effective stimulation; (2) for more productive wells; (3) achieved with higher energy efficiency; (4) in less time. ***
[0022] The following background materials support the above introduction by discussing the vibration spectrum of an impulse in greater detail, highlighting its importance with examples of deleterious effects of mechanical shock and vibration in conventional applications. Building on the background, subsequent sections describe selected alternative designs for adaptive stimulation system components to transform the overall process of well completion through substantive improvements in reliability, efficiency, and efficacy.
BACKGROUND
[0023] The necessity for modified check valve designs (e.g., as described herein and in related patents) may be better appreciated after first considering: (1) the remarkably high failure rates of conventional reciprocating high-pressure pumps (especially their fluid ends), and (2) the substantial uncertainties (e.g., in cost/benefit analysis and technical complexity/reproducibility) associated with multistage well stimulation in unconventional formations. Pump-related issues will be considered initially.
[0024] Frac pumps (also commonly called fracking or well-service pumps) are typically truck-mounted for easy relocation from well-to-well. And they are usually designed in two sections: the (proximal) power section (herein “power end”) and the (distal) fluid section (herein “fluid end”). Each pump fluid end comprises at least one subassembly, and commonly three or more, in a single fluid end housing. Each subassembly comprises a suction valve, a discharge valve, a plunger or piston, and a portion of (or substantially the entirety of) a pump fluid end subassembly housing (shortened herein to “pump housing” or “fluid end housing” or “housing”, depending on the context).
[0025] For each pump fluid end subassembly, its fluid end housing comprises a pumping chamber in fluid communication with a suction bore, a discharge bore, and a piston/plunger bore. A suction valve (i.e., a check valve) within the suction bore, together with a discharge valve (i.e., another check valve) within the discharge bore, control bulk fluid movement from suction bore to discharge bore via the pumping chamber. Note that the term “check valve” as used herein refers to a valve in which a (relatively movable) valve body can cyclically close upon a (relatively stationary) valve seat to achieve substantially unidirectional bulk fluid flow through the valve.
[0026] Pulsatile fluid flow results from cyclical pressurization of the pumping chamber by reciprocating plunger or piston strokes within the plunger/piston bore. Suction and pressure strokes alternately produce wide pressure swings in the pumping chamber (and across the suction and discharge check valves) as the reciprocating plunger or piston is driven by the pump power end.
[0027] Such pumps are rated at peak pumped-fluid pressures in current practice up to about 22,000 psi, while simultaneously being weight-limited due to the carrying capacity of the trucks on which they are mounted. (See, e.g., U.S. Pat. No. 7,513,759 B1, incorporated by reference).
[0028] Due to high peak pumped-fluid pressures, suction check valves experience particularly wide pressure variations between a suction stroke, when the valve opens, and a pressure stroke, when the valve closes. For example, during a pressure stroke with a rod load up to 350,000 pounds, a conventionally rigid/heavy check valve body may be driven longitudinally (by pressurized fluid behind it) toward metal-to-metal impact on a conventional frusto-conical valve seat at closing forces of about 50,000 to over 250,000 pounds (depending on valve dimensions). A portion of total check-valve closure impulse energy (i.e., the total kinetic energy of the moving valve body and fluid at valve seat impact) is thus converted to a short-duration high-amplitude valve-closure energy impulse (i.e., a mechanical shock). As described below, each such mechanical shock is associated with transmission of broad-spectrum vibration energy, the range of vibration spectrum frequencies being an inverse function of valve-closure energy impulse duration.
[0029] Repeated application of dual valve-closure shocks with each pump cycle (i.e., one shock from the suction valve and another shock from the discharge valve) predisposes each check valve, and the pump as a whole, to vibration-induced (e.g., fatigue) damage. (Recall the well-documented progressive cracking of the Liberty Bell with repeated strikes of the clapper, particularly noting the sites of crack progression being significantly distant from the sites of clapper impact). Thus, cumulative valve-closure shocks significantly degrade frac pump reliability, proportional in part to the rigidity and weight of each check valve body.
[0030] The increasing importance of fatigue-related frac pump reliability issues has paralleled the inexorable rise of peak pumped-fluid pressures in new fracking applications. And insight into fatigue-related failure modes has been gained through review of earlier shock and vibration studies, data from which are cited herein. For example, a recent treatise on the subject describes a mechanical shock in terms of its inherent properties in the time domain and in the frequency domain, and also in terms of its effects on structures when the shock acts as the excitation. (see p. 20.5 of Harris' Shock and Vibration Handbook , Sixth Edition, ed. Allan G. Piersol and Thomas L. Paez, McGraw Hill (2010), hereinafter Harris).
[0031] References to time and frequency domains appear frequently in descriptions of acquisition and analysis of shock and vibration data. And these domains are mathematically represented on opposite sides of equations generally termed Fourier transforms. Further, estimates of a shock's structural effects are frequently described in terms of two parameters: (1) the structure's undamped natural frequency and (2) the fraction of critical structural damping or, equivalently, the resonant gain Q (see Harris pp. 7.6, 14.9-14.10, 20.10). (See also, e.g., U.S. Pat. No. 7,859,733 B2, incorporated by reference).
[0032] Digital representations of time and frequency domain data play important roles in computer-assisted shock and vibration studies. In addition, shock properties are also commonly represented graphically as time domain impulse plots (e.g., acceleration vs. time) and frequency domain vibration plots (e.g., spectrum amplitude vs. frequency). Such graphical presentations readily illustrate the shock effects of metal-to-metal valve-closure, wherein movement of a check valve body is abruptly stopped by a valve seat. Relatively high acceleration values and broad vibration spectra are prominent, because each valve-closure impulse response primarily represents a violent conversion of a portion of kinetic energy (of the moving valve body and fluid) to other energy forms.
[0033] Since energy cannot be destroyed in a conventional valve, and a valve can neither store nor convert (i.e., dissipate) more than a small fraction of the valve-closure impulse's kinetic energy, a portion of that energy is necessarily transmitted to the pump housing in the form of broad-spectrum vibration energy. This relationship of (frequency domain) vibration energy to (time domain) kinetic energy, is mathematically represented by a Fourier transform. Such transforms are well-known to those skilled in the art of shock and vibration mechanics. For others, a graphical representation (i.e., plots) rather than a mathematical representation (i.e., equations) may be preferable.
[0034] For example, in a time domain plot, the transmitted energy appears as a high-amplitude impulse of short duration. And a corresponding frequency domain plot of transmitted energy reveals a relatively broad-spectrum band of high-amplitude vibration. *** The breadth of the vibration spectrum is generally inversely proportional to the impulse duration. ***
[0035] Thus, as noted above, a portion of the check valve's cyclical valve-closure kinetic energy is converted to relatively broad-spectrum vibration energy. The overall effect of cyclical check valve closures may therefore be compared to the mechanical shocks that would result from repeatedly striking the valve seat with a commercially-available impulse hammer, each hammer strike being followed by a rebound. Such hammers are easily configured to produce relatively broad-spectrum high-amplitude excitation (i.e., vibration) in an object struck by the hammer. (See, e.g., Introduction to Impulse Hammers at http://www.dytran.com/img/tech/a11.pdf, and Harris p. 20.10).
[0036] Summarizing then, relatively broad-spectrum high-amplitude vibration predictably results from a typical high-energy valve-closure impulse. And frac pumps with conventionally-rigid valves can suffer hundreds of these impulses per minute. Note that the number of impulses per minute (for example, 300 impulses per minute) corresponds to pump plunger strokes or cycles, and this number may be converted to impulses-per-second (i.e., 300/60=5). In this example, the number 5 is sometimes termed a frequency because it is given the dimensions of cycles/second or Hertz (Hz). But the “frequency” thus attributed to pump cycles themselves differs from the spectrum of vibration frequencies resulting from each individual pump cycle energy impulse. The difference is that impulse-generated (e.g., valve-generated) vibration occurs in bursts having relatively broad spectra (i.e., simultaneously containing many vibration frequencies) ranging from a few Hz to several thousand Hz (kHz).
[0037] In conventional frac pumps, nearly all of the (relatively broad-spectrum) valve-generated vibration energy must be transmitted to proximate areas of the fluid end or pump housing because vibration energy cannot be efficiently dissipated in the (relatively rigid) valves themselves. Based on extensive shock and vibration test data (see Harris) it can be expected to excite damaging resonances that predispose the housing to fatigue failures. (See, e.g., U.S. Pat. No. 5,979,242, incorporated by reference). If, as expected, a natural vibration resonance frequency of the housing coincides with a frequency within the valve-closure vibration spectrum, fluid end vibration amplitude may be substantially increased and the corresponding vibration fatigue damage made much worse. (See Harris, p. 1.3).
[0038] Opportunities to limit fluid end damage can reasonably begin with experiment-based redesign to control vibration-induced fatigue. That is, spectra of the equipment vibration frequencies measured after application of test shocks can reveal structural resonance frequencies likely to cause trouble in a particular fluid end. These revealed frequencies are herein termed critical frequencies. For example, a test shock may comprise a half-sine impulse of duration one millisecond, which has predominant spectral content up to about 2 kHz (see Harris, p. 11.22). This spectral content likely overlaps, and thus will excite, a plurality of a fluid end's structural resonance (i.e., critical) frequencies. Excited critical frequencies are then identified with appropriate instrumentation, so attention can be directed to limiting operational vibration at those critical frequencies. This process is tailored to each fluid end, with an appropriate test shock and instrumentation to provide at least one “tested fluid end vibration resonant frequency” to support further reliability improvements.
[0039] Limiting vibration at critical frequencies through use of the above shock tests can be particularly beneficial in blocking progressive fatigue cracking in a structure. If vibration is not appropriately limited, fatigue cracks may grow to a point where fatigue crack size is no longer limited (i.e., the structure experiences catastrophic fracture). The size of cracks just before the point of fracture has been termed the critical crack size. Note that stronger housings are not necessarily better in such cases, since increasing the housing's yield strength causes a corresponding decrease in critical crack size (with consequent earlier progression to catastrophic fracture). (See Harris, p. 33.23).
[0040] It might be assumed that certain valve redesigns proposed in the past (including relatively lighter valve bodies) would have alleviated at least some of the above fatigue-related failure modes. (See, e.g., U.S. Pat. No. 7,222,837 B1, incorporated by reference). But such redesigns emerged (e.g., in 2005 ) when fluid end peak pressures were generally substantially lower than they currently are. In relatively lower pressure applications (e.g., mud pumps), rigid/heavy valve bodies performed well because the valve-closure shocks and associated valve-generated vibration were less severe compared to shock and vibration experienced more recently in higher pressure applications (e.g., fracking). Thus, despite their apparent functional resemblance to impulse hammers, relatively rigid/heavy valves have been pressed into service as candidates for use in frac pump fluid ends. Indeed, they have generally been among the valves most commonly available in commercial quantities during the recent explosive expansion of well-service fracking operations. Substantially increased fluid end failure rates (due, e.g., to cracks near a suction valve seat deck) have been among the unfortunate, and unintended, consequences.
[0041] Under these circumstances, it is regrettable but understandable that published data on a modern 9-ton, 3000-hp well-service pump includes a warranty period measured in hours, with no warranty for valves or weld-repaired fluid ends.
[0042] Such baleful vibration-related results in fluid ends might usefully be compared with vibration-related problems seen during the transition from slow-turning two-cylinder automobile engines to higher-speed and higher-powered inline six-cylinder engines around the years 1903-1910. Important torsional-vibration failure modes suddenly became evident in the new six-cylinder engines, though they were neither anticipated nor understood at the time. Whereas the earlier engines had been under-powered but relatively reliable, torsional crankshaft vibrations in the six-cylinder engines caused objectionable noise (“octaves of chatter from the quivering crankshaft”) and unexpected catastrophic failures (e.g., broken crankshafts). (Quotation cited on p. 13 of Royce and the Vibration Damper , Rolls-Royce Heritage Trust, 2003). Torsional-vibration was eventually identified as the culprit and, though never entirely eliminated, was finally reduced to a relatively minor maintenance issue after several crankshaft redesigns and the development of crankshaft vibration dampers pioneered by Royce and Lanchester.
[0043] Reducing the current fluid end failure rates related to valve-generated vibration in frac pumps requires an analogous modern program of intensive study and specific design changes. The problem will be persistent because repeatedly-applied valve-closure energy impulses cannot be entirely eliminated in check-valve-based fluid end technology. So the valve-closing impulses must be modified, and their associated vibrations damped, meaning that at least a portion of the total vibration energy is converted to heat energy and dissipated (i.e., the heat is rejected to the surroundings). A reduction in total vibration energy results in reduced excitation of destructive resonances in valves, pump housings, and related fluid end structures.
SUMMARY OF THE INVENTION
[0044] Adaptive stimulation systems combine impulse-generated swept-frequency stimulation vibration with cyclically-varying hydraulic pressure to provide adaptive down-hole stimulation. Swept-frequency stimulation vibration arises from cyclical up-shifts and down-shifts of the power spectral density (PSD) of impulse-generated stimulation vibration. The cyclical PSD shifts, in turn, are achieved via closed-loop control of the impulse-generated vibration produced by one or more down-hole stimulators. Adaptive down-hole stimulation can be produced by a single tunable down-hole stimulator or by a plurality of such stimulators spaced apart in a spatial array. A linear array, as schematically illustrated herein (see FIG. 18 ), is one type of spatial array.
[0045] Whether singly or in a spatial array, each stimulator is under closed-loop control. And each stimulator responds to timed stimulator signals (e.g., timed stimulator transmission signals and stimulator shift signals). Each stimulator transmits (in response to a timed stimulator transmission signal) an impulse-generated vibration burst comprising a plurality of vibration frequencies. And each such vibration burst has a power spectral density (PSD) which may be up-shifted or down-shifted under closed-loop control (via a timed stimulator shift signal) to create a swept-frequency spectrum. Connected array stimulators may be controlled by a periodic signal group comprising one or more signals for each stimulator in the array. That is, timed stimulator transmission signals and/or timed stimulator shift signals may be sent as timed signal groups from a programmable controller, at least one signal (either a transmission signal or a shift signal or both) for each stimulator. Signals within a timed signal group may be either simultaneous or sequential. Sequential stimulator signals are separated from each other by discrete time intervals within a signal group.
[0046] Timed stimulator shift signals control each stimulator's adjustable PSD for tuning via that stimulator's adjustable rebound cycle time. For example, adjustable PSD is up-shifted (i.e., increasing relative power in higher vibration frequencies) by reducing rebound cycle time and/or by increasing the resonant frequency of a stimulator's fluid interface. Down-shifting decreases higher vibration frequencies and occurs with increased rebound cycle time. Shifting of an adjustable PSD means that relative transmitted vibration power within a vibration burst may be shifted toward relatively higher or lower frequencies for tuning a single stimulator. Such tuning of one or more stimulators in a spatial array thus tunes the down-hole stimulation array as a whole. Stimulator vibration burst adjustable PSD's are typically adjusted in order to fine-tune a stimulation array for resonance excitation and fracturing of adjacent geologic materials.
[0047] Note that changes in rebound cycle times and/or fluid interface resonant frequencies also affect vibration interference among stimulators within an array (see “interference” below), while changes in stimulator transmission signal times (e.g. either simultaneous or sequential) can affect directional propagation of combined vibration wave fronts from a stimulator array (resulting in, e.g., a directionally-propagated array vibration wave front).
[0048] Note further that the hydraulic pressure environment in which down-hole stimulators operate can be altered by timed pressure signals sent from a programmable controller to one or more frac pumps providing the down-hole hydraulic pressure. Such timed pressure signals are phase-related (e.g., in-phase) with bursts of swept-frequency vibration from one or more down-hole stimulators. Cyclically-varying down-hole hydraulic pressure creates cracks of varying width and depth at varying distances from a wellbore. The hydraulic fluid (e.g., water) filling the cracks thus conveys swept-frequency vibration to excite resonances in geologic material at varying distances from the wellbore. Backscatter vibration from the excited resonances (i.e., feedback) can then be processed in one or more programmable controllers to provide localized estimates of the dynamic response of the geologic material to guide further stimulation.
[0049] As fracturing proceeds to smaller (proppant-sized) fragments having higher resonant frequencies, adjustable PSD's are up-shifted, increasing relative power in higher vibration frequencies (e.g., by reducing rebound cycle time as a function of increases in the backscatter vibration's higher frequency content). Progressive geologic stimulation is thus optimized, with inherent potential for plain-water (or liquefied propane) fracs completed with self-generated proppant.
[0050] A relatively broad vibration frequency spectrum (e.g., comprising a plurality of transmitted frequencies) is characteristic of the impulse-generated swept-frequency stimulation described herein. Combined with cyclically-varying hydraulic pressure, the broad vibration spectrum facilitates adaptive stimulation.
[0051] Adaptive stimulation, in turn, may be subject to controlled directional propagation (of combined vibration wave fronts) from a stimulator array. For example, predetermined sequences of simultaneous and/or sequential timed stimulator signals allow repeated scanning and characterization (via analysis of backscatter vibration) of geologic materials adjacent to a stimulator spatial array in a wellbore. Adaptive stimulation may then be tailored to local down-hole geologic conditions in near-real time. And the tailoring may comprise adjustment of phase relations among (1) timed stimulator shift signals (related to cyclical PSD shifts and swept-frequency vibration), and/or (2) timed stimulator array transmission signals (related to directional control of vibration bursts from the stimulator array), and/or (3) cyclically-varying down-hole hydraulic pressure (related to creating and assessing stimulation vibration effects at varying distances from the wellbore. The result is a parameter-rich control options environment for adaptive stimulation as described herein.
[0052] Further, stimulus tailoring is beneficially applied early in the well completion process because initial geologic fracturing is associated with relatively high down-hole hydraulic pressures and relatively large geologic fragment sizes. In view of the relatively low resonant frequencies of relatively large geologic fragments, the PSD of adaptive stimulation vibration energy may be down-shifted (i.e., fine-tuned). This will increase the relative power (within a vibration burst) of vibration transmitted at those relatively lower frequencies. Such vibration tuning is possible in the impulse-generated feedback-controlled swept-frequency stimulators described herein. Such stimulators feature closed-loop (feedback-controlled) hammer strike and rebound and/or fluid interface resonant frequencies which facilitate localized and near real-time adjustment of transmitted stimulation vibration PSD.
[0053] The need for localization of broad-spectrum impulse-generated stimulation vibration energy means the vibration must be generated and modified down-hole (i.e., in the wellbore) in part to minimize transmission losses as the energy travels to adjacent geologic material. On striking geologic material adjacent to the wellbore, portions of the broad vibration energy spectrum immediately excite resonant vibrations in geologic features whose resonant frequencies were not precisely known initially. By the mechanism of resonance, the variously-sized geologic fragments themselves automatically extract their own portions of vibration energy from the broad range of impulse-generated stimulation vibration frequencies available. The extracted energy, in turn, leads to further vibration-induced geologic fractures and fragmentation.
[0054] Backscatter vibration originating from the stimulated geologic materials reveals the stimulation status and the nature of those materials. Backscatter vibration is sensed in near-real time by detectors on one or more tunable down-hole stimulators. Analysis of backscatter vibration (in one or more programmable controllers) is followed by transmission of one or more control signals to one or more down-hole hydraulic stimulators. Beneficial geologic stimulation is thus obtained using a combination of: (1) minimum applied vibration energy, plus (2) resonance vibration effects assessed via detection of backscatter vibration from the stimulated geologic material.
[0055] It is known by those skilled in the art that accurately characterizing the overall geologic composition of shale reservoirs is difficult. Such reservoirs are substantially different from conventional and other types of unconventional reservoirs. (See, e.g., U.S. Pat. No. 8,731,889 B2, incorporated by reference). Thus various embodiments of the present invention reflect choices among a variety of different functional relationships relating the stimulation vibration parameters.
[0056] Further, certain tunable down-hole stimulation array embodiments may comprise one or more relatively higher-pressure pumps for fluid (e.g., plain water or liquefied propane) that contains no proppant (schematically illustrated and labeled herein as frac pumps). One or more such frac pumps may be combined with one or more relatively lower-pressure pumps for fluid containing exogenous proppant (schematically illustrated and labeled herein as proppant pumps). Such system embodiments facilitate pulsed proppant placement or PPP in previously fractured geologic material. PPP minimizes the total amount of exogenous proppant needed to supplement in situ or self-generated proppant resulting from tunable down-hole stimulation. Thus, the task of stimulation (including proppant placement) is performed step-wise, with each step under closed-loop control for fast convergence on one or more optimal end points.
[0057] Note certain differences between PPP as described herein and the industry practice of pumping different types of slurries or fluids in discrete intervals, that is, as slugs or stages. (See, e.g., U.S. Pat. No. 8,540,024 B2, incorporated by reference). First, proppant addition in PPP is under closed-loop control; it is a function, in part, of backscatter vibration sensed down-hole in near-real time by one or more detectors on each tunable down-hole stimulator. Second, in PPP the proppant-laden fluid may be injected into a wellbore (via one or more separate proppant pumps) at lower pressures than proppant-free fluid associated with the frac pump(s). And Third, proppant provided via the PPP closed-loop system is supplemental to self-generated proppant which is continuously created anew through stimulation vibration transmitted by one or more tunable down-hole stimulators.
[0058] An adaptive down-hole stimulation system embodiment to accomplish such PPP is schematically illustrated herein to emphasize certain advantages stemming from separation of the relatively high-pressure frac pump from the (optionally) relatively lower-pressure proppant pump.
[0059] In the following paragraphs, both generation of broad-spectrum vibration in tunable down-hole stimulators, and incorporation of the stimulators in tunable down-hole stimulation systems, are considered before control of valve-generated vibration in tunable fluid ends. This is to emphasize the role of induced-resonance-excitation vibration and fragmentation in geologic materials for maximizing well productivity.
[0060] Suppression of resonance excitation in tunable fluid ends, on the other hand, limits the destructive effects of valve-generated vibration (for maximizing fluid end reliability). Comparisons will be noted between the related-in-part methods for inducing or suppressing a desired range of resonance-related power spectral densities in systems comprising both tunable down-hole stimulators and tunable fluid ends.
[0061] The desirability of tunable down-hole stimulators in tunable down-hole stimulation systems stems in part from the well-known vertical and horizontal heterogeneity of unconventional reservoirs. Wide variability of geologic materials adjacent to wellbores is common, meaning that consistently-beneficial stimulation design has been difficult to achieve. In current practice, some fracture stages are typically found to be substantially more productive than others, while the cost of fracking varies little from stage-to-stage. Thus, stimulation design currently reflects compromises between the efficiency of a single customized fracture stage and the degraded performance of multiple one-size-fits-all stages that include a variety of geologic materials having different productive potentials.
[0062] Such currently unavoidable inefficiencies are substantially reduced by the advent of new tunable down-hole stimulation systems as described herein. With the new systems, progressive series of customized fracture stages can be realized in near-real time through productive integration of: (1) pumps (optionally having tunable fluid ends), (2) tunable down-hole stimulators, and (3) programmable controllers. Each fracture stage is electively customized in turn, through use of frac diagnostics operating on near-real-time backscatter vibration. Relatively productive stages can be readily identified for optimal stimulation, followed by combination of such stages into strategically important productive clusters.
[0063] And the twin keys to creation of productive clusters in horizontal wellbores are (1) sensing backscatter vibration to generate feedback data collected in different portions of a tunable down-hole stimulation system and (2) processing these and related data (e.g., pressure and/or temperature) in the system's programmable controller to create control signals. Control signals, in turn, direct the operations of subsystems for pumping and/or impulse-generated broad-spectrum vibration to optimize stimulation. Control signals can also (optionally) facilitate accurate placement and adjustment of inflow control devices within a tunable down-hole stimulation system.
[0064] An illustration of such closed-loop control is seen in a first embodiment of a tunable down-hole stimulation system. The system comprises at least one frac pump for creating down-hole hydraulic pressure, together with at least one tunable down-hole stimulator, each stimulator comprising a tunable impulse vibration generator for transmitting vibration hydraulically to adjacent geologic material. The system further comprises a programmable controller for creating a plurality of control signals and transmitting at least one control signal to each frac pump and at least one control signal to each tunable down-hole stimulator. Additionally, each tunable down-hole stimulator comprises at least one accelerometer for sensing both transmitted and backscatter vibration and for transmitting an electrical signal derived therefrom (i.e., for transmitting an electrical signal which is a function of the vibration as sensed by the accelerometer through change in one or more accelerometer electrical parameters such as capacitance, inductance and/or resistance). And the programmable controller is responsive to that electrical signal (i.e., the programmable controller creates at least one control signal as a function of that electrical signal).
[0065] Each tunable down-hole hydraulic stimulator comprises a hammer (or mass) element longitudinally movable within a hollow cylindrical housing having a longitudinal axis, a first end, and a second end, the first end being closed by a fluid interface, and the second end being closed by a driver element. The driver element comprises at least one field emission structure for moving the hammer (or mass) element to strike, and rebound from, the fluid interface during a rebound cycle time to generate broad-spectrum vibration. The fluid interface vibration is in part a function of the fluid interface's effective elastic modulus, and hence its resonant frequencies (which are magnetostrictively responsive to a step-wise adjustable steady-state longitudinal magnetic field applied via current in a peripheral transverse coil).
[0066] Hammer strike and rebound are substantially influenced by the driver element and the fluid interface effective elastic modulus. Driver elements may comprise, e.g., one or more magnetic field emission structures and/or one or more electric field emission structures. A hammer element (i.e., a mass) is longitudinally movable within the cylindrical housing between the driver element and the fluid interface. Such movement is influenced (i.e., controlled in an open-loop or closed-loop manner) by forces exerted on the hammer via the magnetic and/or electrical fields of the field emission structure(s). (See, e.g., U.S. Pat. No. 8,760,252 B2, incorporated by reference). To facilitate hammer element movement, the hammer element may comprise, e.g., one or more permanent magnets, and the driver element's field emission structure(s) may comprise, e.g., one or more electromagnets, at least one with reversible polarity and variable field strength. See the '252 patent for other examples of field emission structures.
[0067] Note that the hammer element is responsive to the driver element both for striking, and rebounding from, the fluid interface. That is, the hammer element may be, e.g., subject to magnetic attraction during certain portions of its longitudinal travel, and subject to magnetic repulsion during other portions of its longitudinal travel. Responsiveness of the hammer element may be achieved via open-loop control (using empirically-derived predictions of hammer element direction and velocity based, e.g., on field emission strength) or closed-loop control (using, e.g., feedback data on hammer element position to calculate direction and velocity of hammer element movement). The latter data may be obtained, e.g., via an electric field sensor on the fluid interface interacting with an electret electric field emission structure on the hammer element.
[0068] Regardless of a stimulator's configuration, stimulation vibration energy may preferably be transmitted from down-hole stimulators in relatively short bursts that are spaced apart in time. Time-delayed backscatter vibration energy may then be sensed at the same or different down-hole stimulators in the periods between bursts of transmitted vibration. But both transmitted and backscatter vibration energy can thus be detected at the fluid interface because they will be present at different times. And one or more accelerometers may provide data on both transmitted and backscatter vibration energy, as well as on the delay time inherent in backscatter vibration.
[0069] Delay time, in turn, may be interpreted (e.g., using frac diagnostics) to indicate the stimulation depth or total distance traveled by the backscatter vibration energy. Further, changes in the backscatter vibration's power spectral density (see below) may also (again using frac diagnostics) be used to characterize the geologic material along a wellbore. Thus, vibration information detected by one or more detectors at a fluid interface, as well as estimates of related parameters (e.g., Doppler shift) that can be extracted therefrom, may be particularly useful when determining the preferred directions, depths and lengths of multiple wellbores to be placed in a relatively confined geologic space.
[0070] Since backscatter vibration emanates from particles experiencing vibration resonance excitation (i.e., stimulation), changes in the backscatter vibration's PSD can reveal changes in the particles' resonance frequencies. And since particles' resonance frequencies are functions of, among other things, particle size and composition (e.g., hardness), analysis of PSD data can directly indicate the local effects of stimulation. In other words, frac diagnostics applied during the stimulation process can provide near-real time information on the changing nature of the stimulated geologic material. *** Specifically, the extent and range of stimulation generated fragmentation can be estimated through analysis of sequential PSD shifts in band-limited backscatter vibration energy. ***
[0071] Responsiveness of a hammer element to a driver element of a tunable down-hole stimulator may be achieved via, e.g., a field emission structure comprising an electromagnet/controller having programmable magnetic field polarity reversal and variable magnetic field strength, as seen, e.g., in linear reversible motors. Control of magnetic field strength is optionally via open-loop and/or closed-loop networks associated with the electromagnet/controller. Note that such magnetic field strength control allows the driver to influence hammer element movement before, during and after each impact via attractive or repelling forces. See. e.g., the '252 patent for further discussion of such forces.
[0072] Note that cyclical changes in magnetic field strength may be characterized by a polarity reversal frequency responsive to the accelerometer signal mentioned earlier and/or to a control signal from a tunable down-hole stimulator system programmable controller. Longitudinal movement of the hammer element is thus responsive in part (e.g., via electromagnetic attraction and repulsion) to the driver element's cyclical magnetic polarity reversal. For example, longitudinal movement of the hammer element striking, and subsequently rebounding from, the fluid interface may be substantially in-phase with the polarity reversal frequency to generate vibration transmitted by the fluid interface.
[0073] Thus, for example, each hammer strike is at least in part a function of magnetic field polarity and strength, and it is followed by a rebound, the cycle time of which is at least in part a function of flexure due to elastic properties (e.g., the effective elastic modulus fluid interface). The rebound may also be a function of the driver element's magnetic field polarity and strength. The duration of the hammer element's entire flexure-rebound cycle (termed herein rebound cycle time) is measured in seconds. The inverse of rebound cycle time has the same dimensions as frequency (e.g., cycles per second) and is termed “characteristic rebound frequency” herein.
[0074] Each hammer strike & rebound applies a mechanical shock to the fluid interface which generates a (relatively-broad) spectrum of stimulation vibration frequencies that are transmitted hydraulically via the fluid interface (and the surrounding down-hole fluid) to the adjacent geologic material. (See the Background section above). The breadth of the generated stimulation vibration spectrum is a reflection of a mechanical shock's duration (i.e., the rebound cycle time). Shortening the rebound cycle time broadens the generated-vibration spectrum (i.e., the spectrum extends to include relatively higher frequencies). The power spectral density is therefore up-shifted, meaning that more of the total power of the transmitted spectrum is represented in the higher frequencies. In this manner, additional stimulation energy (i.e., rock-fracturing energy) may be directed to relatively smaller rock fragments because these fragments have resonances at the relatively-higher stimulation vibration frequencies. Thus, a tunable down-hole stimulator's transmitted stimulation vibration energy may be controlled so as to encourage continued geologic fragmentation to a predetermined fragment size (e.g., to a size for effective function as a proppant).
[0075] Summarizing the above example, hammer rebound movement may be either augmented or impeded by the driver element's magnetic field polarity and strength. The fluid interface effective elastic modulus is a function of step-wise adjustable steady-state current in the peripheral transverse coil. Rebound cycle time is thus controllable, allowing changes in the character of each stimulation vibration burst spectrum generated. Such tuning may comprise, for example, altering a transmitted vibration spectrum's bandwidth and/or changing the relative magnitudes of the vibration spectrum's frequency components (i.e., changing the spectrum's power spectral density). In other words, stimulation energy in the form of vibration spectra transmitted by a tunable down-hole stimulator's fluid interface may be subject (in near-real time) to alterations in response to ongoing results of frac diagnostic calculations operating on backscatter vibration to generate feedback data.
[0076] Note that alternative embodiments of a down-hole stimulation vibration generator may be described as having the form of a linear electrical motor, the hammer element acting as an armature. One such form is seen in railguns, with the armature providing the conducting connection between (parallel) rails. In this case, opposing currents in the rails (and thus the hammer movement) would be controlled by the driver to achieve the desired characteristic rebound frequency. (See, e.g., U.S. Pat. Nos. 8,371,205 B2 and 8,677,877 B2, both incorporated by reference).
[0077] The invention thus facilitates a form of closed-loop (feedback) control of the stimulation process that may be optimized (i.e., to yield better results from less stimulation). Individual tunable down-hole stimulators of the invention can support such an optimization strategy inherently because they naturally produce relatively broad vibration spectra (rather than single-frequency vibration like an aviation black-box pinger). Should a greater frequency range be desired than that obtainable from a single tunable down-hole stimulator, a plurality of such stimulators may be interconnected in a *** tunable down-hole stimulation array ***. (See, e.g., U.S. Pat. Nos. 8,764,661 B2 and 8,571,829 B2, both incorporated by reference).
[0078] An alternate first embodiment of an adaptive stimulation system comprises a frac pump for creating cyclically-varying down-hole hydraulic pressure in response to a timed pressure signal. The system further comprises a plurality of down-hole hydraulic stimulators connected in a spatial array, each said down-hole hydraulic stimulator hydraulically transmitting, in response to a timed stimulator transmission signal, vibration having an adjustable power spectral density. A programmable controller is included for periodically transmitting one said timed pressure signal for said frac pump, one said timed stimulator transmission signal for each said down-hole hydraulic stimulator, and one timed stimulator shift signal for each said down-hole hydraulic stimulator, each said timed pressure signal being in-phase with at least one said timed stimulator transmission signal. Each said down-hole hydraulic stimulator comprises a hollow cylindrical housing having a longitudinal axis, a first end, and a second end, said first end being closed by a fluid interface for transmitting and receiving vibration, and said fluid interface comprising at least one accelerometer for producing an accelerometer feedback signal representing vibration transmitted and received by said fluid interface. A driver element reversibly seals said second end, and a hammer element is longitudinally movable within said housing between said driver element and said fluid interface, said hammer element being responsive to said driver element for striking said fluid interface and rebounding therefrom during an adjustable rebound cycle time to hydraulically transmit a vibration burst comprising a plurality of transmitted frequencies.
[0079] A transverse coil is peripheral to and surrounds said fluid interface, said transverse coil for generating a step-wise adjustable steady-state longitudinal magnetic field intersecting said fluid interface, and said fluid interface being magnetostrictively responsive to said longitudinal magnetic field for altering its effective elastic modulus.
[0080] Note that each said driver element comprises an electromagnet/controller having cyclical magnetic polarity reversal characterized by a variable polarity reversal frequency. Note further that longitudinal movement of each said hammer element is responsive to said cyclical magnetic polarity reversal, and that longitudinal movement of each said hammer element striking, and rebounding from, one said fluid interface is in-phase with one said variable polarity reversal frequency. Additionally note that each said adjustable power spectral density is responsive to one said adjustable rebound cycle time, and each said adjustable rebound cycle time is responsive to one said timed stimulator shift signal.
[0081] Adaptive stimulation system embodiments may incorporate timed stimulator shift signals responsive to one or more accelerometer feedback signals. Further, each adjustable power spectral density may change in-phase with one adjustable rebound cycle time. And a down-hole stimulation array may be tunable via shift of at least one adjustable power spectral density which moves relative transmitted vibration power within transmitted frequencies of at least one said vibration burst. Decreasing at least one adjustable rebound cycle time causes up-shift of at least one adjustable power spectral density to shift relative transmitted vibration power within at least one vibration burst to relatively higher frequencies for tuning the down-hole stimulation array
[0082] An alternate second embodiment of an adaptive stimulation system comprises a frac pump for creating cyclically-varying down-hole hydraulic pressure in response to a timed pressure signal, and a plurality of down-hole hydraulic stimulators connected in a linear stimulation array, each said down-hole hydraulic stimulator hydraulically transmitting a vibration burst in response to a timed stimulator transmission signal. A programmable controller periodically transmits one said timed pressure signal for said frac pump, and a plurality of timed stimulator signals as a signal group, each said signal group including one said timed stimulator transmission signal for each said down-hole hydraulic stimulator and one timed stimulator shift signal for each said down-hole hydraulic stimulator, each said timed pressure signal being in-phase with one said timed stimulator transmission signal. Each said down-hole hydraulic stimulator comprises a hollow cylindrical housing having a longitudinal axis, a first end, and a second end, said first end being closed by a fluid interface for transmitting and receiving vibration, and said fluid interface comprising at least one accelerometer for producing an accelerometer feedback signal representing vibration transmitted and received by said fluid interface. A driver element reversibly seals said second end; and a hammer element is longitudinally movable within said housing between said driver element and said fluid interface, said hammer element being responsive to said driver element for striking said fluid interface and rebounding therefrom during an adjustable rebound cycle time to hydraulically transmit one said vibration burst comprising a plurality of transmitted frequencies as part of a directionally propagated array vibration wave front.
[0083] A transverse coil is peripheral to and surrounds said fluid interface, said transverse coil for generating a step-wise adjustable steady-state longitudinal magnetic field intersecting said fluid interface, and said fluid interface being magnetostrictively responsive to said longitudinal magnetic field for altering its effective elastic modulus.
[0084] Note that each said driver element comprises an electromagnet/controller having cyclical magnetic polarity reversal characterized by a variable polarity reversal frequency, and longitudinal movement of each said hammer element is responsive to said cyclical magnetic polarity reversal. Note further that longitudinal movement of each said hammer element striking, and rebounding from, one said fluid interface is in-phase with one said variable polarity reversal frequency, and that said timed stimulator transmission signals within each said signal group are simultaneous signals. Note additionally that said directionally propagated array vibration wave front is responsive to said simultaneous signals, and that each said variable polarity reversal frequency is responsive to one said timed stimulator transmission signal. And note finally that each said adjustable rebound cycle time is responsive to one said timed stimulator shift signal, and that each said timed stimulator shift signal is responsive to one said accelerometer feedback signal.
[0085] Further in alternate embodiments of adaptive stimulation systems, the frac pump may comprise a fluid end having at least one tested fluid end vibration resonant frequency. The fluid end may additionally comprise at least one tunable vibration damper, each tunable vibration damper being tuned to at least one tested fluid end vibration resonant frequency. And the tunable vibration damper may comprise a tunable check valve assembly, each said a tunable check valve assembly comprising a valve body having a central viscoelastic element coupled to a peripheral groove viscoelastic element via a plurality of radial viscoelastic elements in tension to form a tuned radial array having a resonant vibration frequency equal to one said tested fluid end vibration resonant frequency.
[0086] An alternate third embodiment of an adaptive stimulation system comprises a frac pump for creating cyclically-varying down-hole hydraulic pressure in response to a timed pressure signal. A plurality of down-hole hydraulic stimulators is connected in a linear stimulation array, each said down-hole hydraulic stimulator comprising an impulse vibration generator responsive to a timed stimulator transmission signal and a timed stimulator shift signal, each said impulse vibration generator being tuned via an adjustable rebound cycle time and/or an adjustable fluid interface effective elastic modulus (see transverse coil below) to periodically hydraulically transmit, in response to a timed stimulator transmission signal, a vibration burst comprising a plurality of vibration frequencies as part of a directionally propagated array vibration wave front.
[0087] A transverse coil is peripheral to and surrounds the fluid interface, the transverse coil generating a step-wise adjustable steady-state longitudinal magnetic field intersecting the fluid interface, and the fluid interface being magnetostrictively responsive to the longitudinal magnetic field for altering its effective elastic modulus.
[0088] A programmable controller periodically transmits one said timed pressure signal, a plurality of said timed stimulator transmission signals, and a plurality of said timed stimulator shift signals as a signal group, each said signal group including one said timed stimulator transmission signal and one said timed stimulator shift signal for each said down-hole hydraulic stimulator, each said timed pressure signal being in-phase with one said timed stimulator transmission signal. Note that each said vibration burst comprises a plurality of vibration frequencies and has an adjustable power spectral density that is responsive to one said adjustable rebound cycle time. Note further that said timed stimulator transmission signals within each said signal group are sequential signals, and that said directionally propagated array vibration wave front is responsive to said sequential signals. And note additionally that each said down-hole hydraulic stimulator comprises at least one accelerometer for sensing vibration and transmitting an accelerometer feedback signal derived therefrom, and that each said timed stimulator shift signal is responsive to one said accelerometer feedback signal. And note finally that each said adjustable rebound cycle time is responsive to one said timed stimulator shift signal.
[0089] Further, the frac pump of alternate embodiments of adaptive stimulation systems may comprise a tunable valve, each tunable valve comprising a valve body and a valve seat. The valve body comprises a peripheral valve seat interface having a convex curvature which undergoes a substantially elastic concave flexure with slight circular rotation as the valve body seats against the valve seat. The valve seat, in turn, has a concave mating surface with correspondingly less curvature than the peripheral valve seat interface. So the peripheral valve seat interface achieves a circular rolling contact seal with the concave mating surface of the valve seat. As described elsewhere herein, a circular rolling contact seal increases longitudinal compliance of a tunable valve, constituting tuning of the valve to absorb and convert (e.g., via hysteresis loss) a portion of valve closure impact (i.e., kinetic) energy to heat energy. Dissipation of valve closure impact energy as heat rather than excitation of destructive pump vibration resonance(s) tends to improve the reliability of a second alternate array as a whole.
[0090] As noted above, part of the vibration sensed at the fluid interface typically includes time-delayed backscatter vibration. It also may contain temperature data related to the degree of rock fracturing and/or fragmentation, including the size of rock fragments. Fracturing-related temperature changes may be induced in part by mechanical inefficiencies secondary to vibration earlier transmitted from the fluid interface. (See U.S. Pat. No. 8,535,250 B2, incorporated by reference). Hence, temperature-related well-stimulation data can be used to augment control of fracturing resulting from transmitted stimulation vibration.
[0091] One determinant of imposed stimulation is the hammer element's striking face, which has a predetermined modulus of elasticity that may be relatively high (approximately that of mild steel, for example) if a relatively broad spectrum of stimulation vibration is desired. Conversely, a lower modulus of elasticity may be chosen to reduce the highest frequency components of stimulation vibration spectra.
[0092] The spectra of stimulation vibration desired for a particular application will generally be chosen to encompass one or more of the (estimated) resonant frequencies of the geologic structures being stimulated (including resonant frequencies before, during, and after stimulation). For example, it has been reported that vibration frequencies in the ultrasound range (i.e., >20 kHz) can improve the permeability of certain porous media surrounding a well. On the other hand, vibration frequencies <20 kHz may propagate with less loss, while still significantly increasing well flow rates. (See, e.g., U.S. patent publication number 2014/0027110 A1, incorporated by reference). Optimization of the stimulation process may be facilitated using estimates obtained via (1) one or more programmable microprocessors in the tunable down-hole stimulator and/or (2) one or more programmable microprocessors in the tunable down-hole stimulation system programmable controller. Such estimates may be based in part, e.g., on the portion(s) of the backscatter vibration energy from stimulated porous media.
[0093] Note that a tunable down-hole stimulator is intended for down-hole use within a fluid environment maintained in the wellbore via (1) fluids collected through explosively-formed perforations or preformed slots in the wellbore casing from the surrounding geologic formations and/or via (2) addition of fluid at the wellhead to equal or exceed the filtration rate (sometimes termed the leakoff rate). (See U.S. Pat. No. 8,540,024 B2, incorporated by reference). Since the tunable down-hole stimulator (i.e., a tunable hydraulic stimulator) can be completely sealed from internal contact with surrounding fluid, its use is not subject to dielectric strength and conductivity limitations (e.g., “compensation dielectric liquid” as required in U.S. patent publication number 2014/0027110 A1 cited above) that are common in pulsed power apparatus. (See also U.S. Pat. No. 8,616,302 B2, incorporated by reference).
[0094] Note also that tunable resilient circumferential seals are electively provided to isolate predetermined explosively-formed perforations or preformed slots in portions of the wellbore casing (analogous in part to swell packers). (See, e.g., U.S. patent application number 2014/0051612 A1, incorporated by reference). The circumferential seal comprises a circular tubular area which may contain at least one shear-thickening fluid to assist tuning to a preferred frequency range. And the fluid may further comprise nanoparticles which, in conjunction with the shear-thickening fluid, also facilitate tuning of the seal as well as heat scavenging.
[0095] Frequency domain down-shifting (e.g., by increasing longitudinal compliance) and damping (e.g., via viscoelastic and/or shear-thickening materials) both assist vibration control by converting valve-closure energy to heat and dissipating it in each tunable component present in a tunable fluid end embodiment. That is, down-shifting effectively attenuates and/or limits the bandwidth(s) of valve-generated vibration. Subsequent (coordinated) damping assists in converting a portion of this band-limited vibration to heat.
[0096] Both down-shifting and damping are dependent in part on constraints causing shear-stress alteration (that is, “tuning”) imposed on one or more viscoelastic and/or shear-thickening materials in each tunable component. Additionally, hysteresis or internal friction (see Harris, p. 5.7) associated with mechanical compliance of certain structures (e.g., valve bodies or springs) may aid damping by converting vibration energy to heat (i.e., hysteresis loss). (See Harris, p. 2.18).
[0097] Mechanical compliance is manifest, for example, in elastic valve body flexures secondary to repetitive longitudinal compressive forces (i.e., plunger pressure strokes). Each such flexure is followed by a hysteresis-limited elastic rebound, the duration of the entire flexure-rebound interval being termed herein rebound cycle time. As noted above, the inverse of rebound cycle time is termed herein “characteristic rebound frequency.” Cumulative rebound cycle energy loss in the form of heat (e.g., hysteresis loss plus friction loss) is continuously transported for redistribution within the valve body and eventual rejection to the valve body surroundings (including, e.g., the pumped fluid). This heat loss represents a reduction in the available energy content (and thus the damage-causing potential) of the valve-closure energy impulse.
[0098] Note that lengthening rebound cycle time to beneficially narrow the valve-generated vibration spectrum is substantially influenced by a tunable valve assembly's increased longitudinal compliance associated with rolling seal contact (i.e., comprising valve body flexure and rebound) described herein between the valve body's peripheral valve seat interface and the tunable valve seat's mating surface.
[0099] Briefly summarizing, as each tunable component present in a tunable fluid end embodiment absorbs, converts and redistributes (i.e., dissipates) a portion of valve closing impulse shock energy, only a fraction of the original closing impulse energy remains at critical frequencies capable of exciting destructive resonant frequencies in the fluid end. Following vibration down-shifting, a significant portion of valve-closure energy has been shifted to lower frequency vibration through structural compliance as described above. This attenuated vibration is then selectively damped (i.e., dissipated as heat) at shifted frequencies via one or more of the tunable components. While tunable components may be relatively sharply tuned (e.g., to act as tuned mass dampers for specific frequencies), they may alternately be more broadly tuned to account for a range of vibration frequencies encountered in certain pump operations.
[0100] Note that vibration absorption at specific frequencies (e.g., via dynamic or tuned absorbers) may have limited utility in frac pumps because of the varying speeds at which the pumps operate and the relatively broad bandwidths associated with valve-closing impulse shocks. In contrast, the process of down-shifting followed by damping is more easily adapted to changes inherent in the pumps' operational environment. Damping may nevertheless be added to a dynamic absorber to increase its effective frequency range for certain applications. (See, e.g., tuned vibration absorber and tuned mass damper in ch. 6 of Harris).
[0101] Selective damping of vibration frequencies near the resonant frequencies of fluid ends is desirable for the same reason that soldiers break step when they march over a bridge—because even relatively small amounts of vibration energy applied at the bridge's resonant frequency can cause catastrophic failure. Various combinations of the tunable components described herein are particularly beneficial because they focus the functions of vibration-limiting resources on minimization of vibration energy present in a fluid end near its housing's critical frequencies.
[0102] Note that a variety of optimization strategies for vibration attenuation and damping may be employed in specific cases, depending on parameters such as the Q (or quality) factor attributable to each fluid end resonance. The fluid end response to excitation of a resonance may be represented graphically as, for example, a plot of amplitude vs. frequency. Such a Q response plot typically exhibits a single amplitude maximum at the local fluid end resonance frequency, with decreasing amplitude values at frequencies above and below the resonance. At an amplitude value about 0.707 times the maximum value (i.e., the half-power point), the amplitude plot corresponds not to a single frequency but to a bandwidth between upper and lower frequency values on either side of the local fluid end resonance. The quality factor Q is then estimated as the ratio of the resonance frequency to the bandwidth. (See, e.g., pp. 2-18, 2-19 of Harris). (See also U.S. Pat. No. 7,113,876 B2, incorporated by reference).
[0103] Lower Q connotes the presence of more damping and a wider bandwidth (i.e., a relatively broader band of near-resonant frequencies). And higher Q connotes less damping and a narrower bandwidth (ideally, zero damping and a single resonant frequency). Since ideal fluid end resonances are not encountered in practice, optimization strategies typically include choice of the peak resonant frequency and Q of the tunable component in light of the peak resonant frequency and Q of the fluid end resonance of interest. Tunable component resonant frequencies identified herein as “similar” to fluid end or pump housing resonances are thus understood to lie generally in the frequency range indicated by the upper and lower frequency values of the relevant Q response half-power bandwidth.
[0104] Note that the peak (or representative) frequency of a tunable component or a fluid end resonance may not be unambiguously obtainable. Thus, optimization of tunable component vibration damping may be an iterative empirical process and may not be characterized by a single-valued solution. Note also that tunable component resonant frequencies may be intentionally “detuned” (i.e., adjusted to slightly different values from nominal resonant or peak frequencies) in pursuit of an overall optimization strategy. The critical frequencies proximate to a fluid end suction bore may differ, for example, from the critical frequencies proximate to the same fluid end's plunger bore due to the different constraints imposed by structures proximate the respective bores.
[0105] What follows are descriptions of the structure and function of each tunable component that may be present in a tunable fluid end embodiment comprising a housing with appropriate bores. Within each housing's bores are a suction valve, a discharge valve, and a plunger or piston. When a tunable fluid end comprises multiple subassemblies, each subassembly has at least one tunable component.
[0106] One tunable component described herein is a tunable check valve assembly (one being found in each tunable check valve). Installed in a fluid end for high pressure pumping, a tunable check valve assembly comprises at least one vibration damper or, in certain embodiments, a plurality of (radially-spaced) vibration dampers disposed in a valve body. Each vibration damper constitutes at least one tunable structural feature. Since the fluid end has at least a first fluid end resonance frequency, at least one vibration damper has (i.e., is tuned to) at least a first predetermined assembly resonant frequency similar to the first fluid end resonance (i.e., resonant frequency). If, for example, the fluid end has a second fluid end resonance frequency (a common occurrence), a single vibration damper and/or at least one of a plurality of vibration dampers may have (i.e., be tuned to) at least a second predetermined assembly resonant frequency similar to the second fluid end resonance frequency. In general, the specific manner of damping either one or a plurality of fluid end resonance frequencies with either one or a plurality (but not necessarily the same number) of vibration dampers is determined during the optimization process noted above.
[0107] Each of the sample embodiments of tunable check valve assemblies schematically illustrated herein comprises a check valve body having guide means (to maintain valve body alignment during longitudinal movement) and a peripheral valve seat interface. A peripheral groove spaced radially apart from a central reservoir is present in certain embodiments, and a viscoelastic structure may be present in the peripheral groove (i.e., the groove damping element). In one such embodiment, the assembly's vibration dampers comprise a plurality of radially-spaced viscoelastic body structures disposed in the groove and reservoir, the viscoelastic groove element comprising a groove circular tubular area. In alternative embodiments, the viscoelastic reservoir (or central) damping element may be replaced by a central spring-mass damper. A viscoelastic central damper may be tuned, for example, via a flange centrally coupled to the valve body. A spring-mass central damper may be tuned, for example, by adjusting spring constant(s) and/or mass(es), and may also or additionally be tuned via the presence of a viscous or shear-thickening liquid in contact with one or more damper elements.
[0108] A reservoir (or central) damping element tuning frequency may be, as noted above, a first predetermined assembly resonant frequency similar to a first fluid end resonance. Analogously, the groove circular tubular area may comprise at least one shear thickening material providing the means to tune the groove damping element to at least a second predetermined assembly resonant frequency similar, for example, to either a first or second fluid end resonant frequency. The choice of tuning frequencies for the reservoir and groove damping elements is not fixed, but is based on a chosen optimization strategy for vibration damping in each fluid end.
[0109] Note that phase shifts inherent in the (nonlinear) operation of certain vibration dampers described herein create the potential for a plurality of resonant frequencies in a single vibration damper.
[0110] Note also that the longitudinal compliance of a tunable check valve assembly affects its rebound cycle time and thus influences vibration attenuation (i.e., downshifting or spectrum narrowing), which constitutes a form of tuning. Further, vibration dampers in alternative tunable check valve assembly embodiments may comprise spring-mass combinations having discrete mechanical components in addition to, or in place of, viscoelastic and/or shear-thickening components. An example of such a spring-mass combination within a valve body central reservoir is schematically illustrated herein.
[0111] Another tunable component described herein is a tunable valve seat, certain embodiments of which may be employed with a conventional valve body or, alternatively, may be combined with a tunable check valve assembly to form a tunable check valve. A tunable valve seat in a fluid end for high pressure pumping comprises a concave mating surface and/or a lateral support assembly longitudinally spaced apart from a mating surface. A lateral support assembly, when present, is adjustably secured (e.g., on a lateral support mounting surface) or otherwise coupled to the mating surface. A lateral support assembly is a tunable structural feature for resiliently coupling the tunable valve seat to a fluid end housing (and thus damping vibrations therein). That is, a lateral support assembly (and thus a tunable valve seat of which it is a part) has at least one tunable valve seat resonant frequency similar to at least one fluid end resonant frequency. Further, a lateral support assembly may be combined with a concave mating surface to provide two tunable structural features in a single tunable valve seat. Tunability of the concave mating surface inheres in its influence on rebound cycle time through the predetermined orientation and degree of curvature of the concave mating surface. Since it constitutes a tunable structural feature, a concave mating surface may be present in a tunable valve seat without a lateral support assembly. In the latter case, the concave mating surface will be longitudinally spaced apart from a pump housing interface surface, rather than a lateral support mounting surface (examples of these two surfaces are schematically illustrated herein). In light of a tunable valve seat's potential for embodying either one or two tunable structural features, a plurality of tunable valve seat resonant frequencies may characterize a single tunable valve seat, with the respective frequencies being chosen in light of the fluid end resonance(s) and the valve closure impulse vibration spectrum.
[0112] A support assembly's one or more suitably-secured circular viscoelastic support elements resiliently couple the tunable valve seat to a fluid end housing (thus damping vibrations therein). At least one such viscoelastic support element comprises a support circular tubular area. And each support circular tubular area, in turn, comprises at least one shear thickening material having (i.e., being tuned to a resonance frequency similar to) at least one seat resonant frequency that may be chosen to be similar to at least one fluid end resonant frequency.
[0113] Still another tunable component described herein is a tunable radial array disposed in a valve body. In a schematically illustrated embodiment, the valve body comprises guide means, a peripheral valve seat interface, and a fenestrated peripheral groove spaced radially apart from a central reservoir. A viscoelastic body element disposed in the groove (the groove element) is coupled to a viscoelastic body element disposed in the reservoir (the reservoir element) by a plurality of viscoelastic radial tension members passing through a plurality of fenestrations in the peripheral groove. Each radial tension member comprises at least one polymer composite and functions to couple the groove element with the reservoir element, a baseline level of radial tension typically arising due to shrinkage of the viscoelastic elements during curing. The tensioned radial members, as schematically illustrated herein, assist anchoring of the coupled groove element firmly within the peripheral seal-retention groove without the use of adhesives and/or serrations as have been commonly used in anchoring conventional valve seals. Radial tension members also create a damped resilient linkage of groove element to reservoir element (analogous in function to a spring-mass damper linkage). This damped linkage can be “tuned” to approximate (i.e., have a resonance similar to) one or more critical frequencies via choice of the viscoelastic and/or composite materials in the damped linkage. Note that radial tension members also furnish a transverse preload force on the valve body, thereby altering longitudinal compliance, rebound cycle time (and thus characteristic rebound frequency), and vibration attenuation.
[0114] And another tunable component described herein is a tunable plunger seal comprising at least one lateral support assembly (analogous to that of a tunable valve seat) securably and sealingly positionable along a plunger. Typically, a lateral support assembly will be installed in a packing box (sometimes termed a stuffing box) or analogous structure. The tunable plunger seal's lateral support assembly is analogous in structure and function to that of a tunable valve seat, as are the tuning procedures described above.
[0115] Note that the lateral support assembly of either a tunable valve seat or a tunable plunger seal resiliently links the respective valve seat or plunger with adjacent portions of a fluid end housing, effectively creating a spring-mass damper coupled to the housing. This damped linkage can be “tuned” to approximate one or more critical frequencies via, e.g., shear-thickening materials in the respective circular tubular areas as described herein.
[0116] Analogous damped linkages between the housing and one or more auxiliary masses may be incorporated in tunable fluid end embodiments for supplemental vibration damping at one or more fluid end resonant frequencies (e.g., auxiliary tuned vibration absorbers and/or tuned-mass dampers). Additionally or alternatively, one or more damping surface layers (applied, e.g., as metallic, ceramic and/or metallic/ceramic coatings) may be employed for dissipating vibration and/or for modifying one or more fluid end resonant frequencies in pursuit of an overall optimization plan for fluid end vibration control. Such damping surface layers may be applied to fluid ends by various methods known to those skilled in the art. These methods may include, for example, cathodic arc, pulsed electron beam physical vapor deposition (EB-PVD), slurry deposition, electrolytic deposition, sol-gel deposition, spinning, thermal spray deposition such as high velocity oxy-fuel (HVOF), vacuum plasma spray (VPS) and air plasma spray (APS). The surface layers may be applied to the desired fluid end surfaces in their entirety or applied only to specified areas. Each surface layer may comprise a plurality of sublayers, at least one of which may comprise, for example, titanium, nickel, cobalt, iron, chromium, silicon, germanium, platinum, palladium and/or ruthenium. An additional sublayer may comprise, for example, aluminum, titanium, nickel, chromium, iron, platinum, palladium and/or ruthenium. One or more sublayers may also comprise, for example, metal oxide (e.g., zirconium oxide and/or aluminum oxide) and/or a nickel-based, cobalt-based or iron-based superalloy. (See e.g., U.S. Pat. No. 8,591,196 B2, incorporated by reference).
[0117] In addition to composite viscoelastic element inclusions, control mechanisms for alteration of tunable component resonant frequencies further include the number, size and spacing of peripheral groove fenestrations. When fenestrations are present, they increase valve assembly responsiveness to longitudinal compressive force while stabilizing viscoelastic and/or composite peripheral groove elements. Such responsiveness includes, but is not limited to, variations in the width of the peripheral groove which facilitate “tuning” of the groove together with its viscoelastic element(s).
[0118] Note that when a tunable check valve body distorts substantially elastically under the influence of a closing energy impulse, its associated viscoelastic element(s) simultaneously experience(s) shear stress in accommodating the distortion. The resulting viscoelastic shear strain, however, is at least partially time-delayed. And the time delay introduces a phase-shift useful in damping valve-generated vibration (i.e., reducing its amplitude). Analogous time-delay phase shift occurs in a mass-spring damper comprising discrete mechanical elements. Similarly, each instance of compliance takes place over a finite time interval. For example, the duration of a closing energy impulse is effectively increased (and the vibration spectrum correspondingly narrowed) as a function of compliance.
[0119] Compliance may be associated with distortions of both groove and reservoir viscoelastic body elements, resulting in viscoelastic stress and its associated time-dependent strain. But the mechanisms differ in the underlying distortions. In a peripheral groove, for example, proximal and distal groove walls respond differently to longitudinal compressive force on the tunable check valve assembly. They generally move out-of-phase longitudinally, thereby imposing time-varying compressive loads on the groove viscoelastic element. Thus the shape of the groove (and the overall compliance of the groove and its viscoelastic element) changes with time, making the groove as a whole responsive to longitudinal force on the assembly.
[0120] Peripheral groove fenestrations increase groove responsiveness to longitudinal force. As schematically illustrated herein, fenestrations increase groove responsiveness by changing the coupling of the proximal groove wall to the remainder of the valve body (see Detailed Description herein).
[0121] In the reservoir, in contrast, responsiveness to longitudinal force may be modulated by an adjustable preload flange centrally coupled to the valve body. The flange imposes a shear preload on the viscoelastic reservoir element (i.e., shear in addition to that imposed by the reservoir itself and/or by the closing energy impulse acting on the viscoelastic element via the pumped fluid). The amount of shear preload varies with the (adjustable) radial and longitudinal positions of the flange within the reservoir. The overall compliance and resonances of the reservoir and its viscoelastic element may be predictably altered by such a shear preload, which is imposed by the flange's partial constraint of the viscoelastic reservoir element. Note that when reservoir and groove viscoelastic body elements are coupled by a plurality of radial tension members, as in a tunable radial array, the radial tension members lying in groove wall fenestrations allow transmission of shear stress between the groove and reservoir viscoelastic elements.
[0122] As noted above, alterations in compliance (with its associated hysteresis loss) contribute to predetermined vibration spectrum narrowing. Such compliance changes (i.e., changes in displacement as a function of force) may be achieved through adjustment of constraint. Constraint, in turn, may be achieved, e.g., via compression applied substantially longitudinally by the adjustable preload flange to a constrained area of the viscoelastic reservoir element. In embodiments comprising a central longitudinal guide stem, the constrained area may be annular. And adjacent to such an annular constrained area may be another annular area of the viscoelastic reservoir element which is not in contact with the adjustable preload flange (i.e., an annular unconstrained area). This annular unconstrained area is typically open to pumped fluid pressure.
[0123] Preload flange adjustment may change the longitudinal compliance of the tunable check valve assembly by changing the effective flange radius and/or the longitudinal position of the flange as it constrains the viscoelastic reservoir element. Effective flange radius will generally exceed actual flange radius due to slowing of (viscous) viscoelastic flow near the flange edge. This allows tuning of the check valve assembly to a first predetermined assembly resonant frequency for maximizing hysteresis loss. Stated another way, by constraining a vibrating structure (e.g., an area of the viscoelastic reservoir element), it is possible to force the vibrational energy into different modes and/or frequencies. See, e.g., U.S. Pat. No. 4,181,027, incorporated by reference.
[0124] The invention thus includes means for constraining one or more separate viscoelastic elements of a valve assembly, as well as means for constraining a plurality of areas of a single viscoelastic element. And such constraint may be substantially constant or time-varying, with correspondingly different effects on resonant frequencies. Peripherally, time-varying viscoelastic element constraint may be provided by out-of-phase longitudinal movement of peripheral groove walls. In contrast, time-varying viscoelastic element constraint may be applied centrally by a flange coupled to the valve body.
[0125] Note that in certain embodiments, the preload flange may comprise a substantially cylindrical periphery associated with substantially longitudinal shear. Other embodiments may comprise a non-cylindrical periphery for facilitating annular shear preload having both longitudinal and transverse components associated with viscoelastic flow past the flange. Such an invention embodiment provides for damping of transverse as well as longitudinal vibration. Transverse vibration may originate, for example, when slight valve body misalignment with a valve seat causes abrupt lateral valve body movement during valve closing.
[0126] Note also that one or more flanges may or may not be longitudinally fixed to the guide stem for achieving one or more predetermined assembly resonant frequencies.
[0127] Note further that when a nonlinear system is driven by a periodic function, such as can occur with harmonic excitation, chaotic dynamic behavior is possible. Depending on the nature of the nonlinear system, as well as the frequency and amplitude of the driving force, the chaotic behavior may comprise periodic oscillations, almost periodic oscillations, and/or coexisting (multistable) periodic oscillations and nonperiodic-nonstable trajectories (see Harris, p. 4-28).
[0128] In addition to a shift in the tunable check valve assembly's vibrating mode, incorporation of at least one circular tubular area containing at least one shear-thickening material within the viscoelastic groove element increases impulse duration by slightly slowing valve closure due to reinforcement of the viscoelastic groove element. Increased impulse duration, in turn, narrows the closing energy impulse vibration spectrum. And shear-thickening material itself is effectively constrained by its circular location within the viscoelastic groove element(s).
[0129] The shear-thickening material (sometimes termed dilatant material) is relatively stiff near the time of impact and relatively fluid at other times. Since the viscoelastic groove element strikes a valve seat before the valve body, complete valve closure is slightly delayed by the shear-thickening action. The delay effectively increases the valve-closure energy impulse's duration, which means that vibration which is transmitted from the tunable check valve assembly to its (optionally tunable) valve seat and pump housing has a relatively narrower spectrum and is less likely to excite vibrations that predispose a pump housing to early fatigue failure. The degree of spectrum narrowing can be tuned to minimize excitation of known pump housing resonances by appropriate choice of the shear-thickening material. Such vibration attenuation, and the associated reductions in metal fatigue and corrosion susceptibility, are especially beneficial in cases where the fluid being pumped is corrosive.
[0130] The functions of the viscoelastic groove element, with its circular shear-thickening material, are thus seen to include those of a conventional valve seal as well as those of a tunable vibration attenuator and a tunable vibration damper. See, e.g., U.S. Pat. No. 6,026,776, incorporated by reference. Further, the viscoelastic reservoir element, functioning with a predetermined annular shear preload provided via an adjustable preload flange, can dissipate an additional portion of valve-closure impulse energy as heat while also attenuating and damping vibration. And viscoelastic fenestration elements, when present, may contribute further to hysteresis loss as they elastically retain the groove element in the seal-retention groove via coupling to the reservoir element. Overall hysteresis loss in the viscoelastic elements combines with hysteresis loss in the valve body to selectively reduce the bandwidth, amplitude and duration of vibrations that the closing impulse energy would otherwise tend to excite in the valve and/or pump housing.
[0131] Examples of mechanisms for such selective vibration reductions are seen in the interactions of the viscoelastic reservoir element with the adjustable preload flange. The interactions contribute to hysteresis loss in a tunable check valve assembly by, for example, creating what has been termed shear damping (see, e.g., U.S. Pat. No. 5,670,006, incorporated by reference). With the preload flange adjustably fixed centrally to the check valve body (e.g., fixed to a central guide stem), valve-closure impact causes both the preload flange and guide stem to temporarily move distally with respect to the (peripheral) valve seat interface (i.e., the valve body experiences a concave-shaped flexure). The impact energy associated with valve closure causes temporary deformation of the check valve body; that is, the valve body periphery (e.g., the valve seat interface) is stopped by contact with a valve seat while the central portion of the valve body continues (under inertial forces and pumped-fluid pressure) to elastically move distally. Thus, the annular constrained area of the viscoelastic reservoir element (shown constrained by the preload flange in the schematic illustrations herein) moves substantially countercurrent (i.e., in shear) relative to the annular unconstrained area (shown radially farther from the guide stem and peripheral to the preload flange). That is, relative distal movement of the preload flange thus tends to extrude the (more peripheral) annular unconstrained area proximally. Energy lost (i.e., dissipated) in connection with the resulting shear strain in the viscoelastic element is subtracted from the total closing impulse energy otherwise available to excite destructive flow-induced vibration resonances in a valve, valve seat and/or pump housing. See, e.g., U.S. Pat. No. 5,158,162, incorporated by reference.
[0132] Note that in viscoelastic and shear-thickening materials, the relationship between stress and strain (and thus the effect of material constraint on resonant frequency) is generally time-dependent and non-linear. So a desired degree of non-linearity in “tuning” may be predetermined by appropriate choice of viscoelastic and shear-thickening materials in a tunable check valve assembly or tunable check valve.
[0133] Another aspect of the interaction of the viscoelastic reservoir element with an adjustable preload flange contributes to vibration damping and/or absorption in a tunable check valve assembly. As a result of compliance in the viscoelastic element, longitudinal movement of a guide stem and a coupled preload flange results in a phase lag as shear stress develops within the viscoelastic material. This is analogous to the phase lag seen in the outer ring movement in an automotive torsional vibration damper or the antiphase movement of small masses in an automotive pendulum vibration damper. See, e.g., the '776 patent cited above. Adjusting the shear preload flange as described above effectively changes the tunable check valve assembly's compliance and thus the degree of phase lag. One may thus, in one or more limited operational ranges, tune viscoelastic element preload to achieve effective vibration damping plus dynamic vibration absorption at specific frequencies of interest (e.g., pump housing resonant frequencies).
[0134] To achieve the desired hysteresis loss associated with attenuation and vibration damping effects described herein, different viscoelastic and/or composite elements may be constructed to have specific elastic and/or viscoelastic properties. Note that the term elastic herein implies substantial characterization by a storage modulus, whereas the term viscoelastic herein implies substantial characterization by a storage modulus and a loss modulus. See, e.g., the '006 patent cited above.
[0135] Elastic longitudinal compliance of a tunable check valve assembly results in part from elastic properties of the materials comprising the tunable check valve assembly. Such elastic properties may be achieved through use of composites comprising reinforcement materials as, for example, in an elastic valve body comprising steel, carbon fiber reinforced polymer, carbon nanotube/graphene reinforced polymer, and/or carbon nanotube/graphene reinforced metal matrix. The polymer may comprise a polyaryletherketone (PAEK), for example, polyetheretherketone (PEEK). See, e.g., U.S. Pat. No. 7,847,057 B2, incorporated by reference.
[0136] Note that the description herein of valve body flexure as concave-shaped refers to a view from the proximal or high-pressure side of the valve body. Such flexure is substantially elastic and may be associated with slight circular rotation (i.e., a circular rolling contact) of the valve body's valve seat interface with the valve seat itself. When the degree of rolling contact is sufficient to justify conversion of the valve seat interface from a conventional frusto-conical shape to a convex curved shape (which may include, e.g., circular, elliptic and/or parabolic portions), a curved concave tunable valve seat mating surface may be used. In such cases, the valve seat interface has correspondingly greater curvature than the concave tunable valve seat mating surface (see Detailed Description herein). Such rolling contact, when present, augments elastic formation of the concave valve body flexure on the pump pressure stroke, reversing the process on the suction stroke.
[0137] The circular rolling contact described herein may be visualized by considering the behavior of the convex valve seat interface as the valve body experiences concave flexure (i.e., the transformation from a relatively flat shape to a concave shape). During such flexure the periphery of the valve seat interface rotates slightly inwardly and translates slightly proximally (relative to the valve body's center of gravity) to become the proximal rim of the concave-shaped flexure.
[0138] While substantially elastic, each such valve body flexure is associated with energy loss from the closing energy impulse due to hysteresis in the valve body. Frictional heat loss (and any wear secondary to friction) associated with any circular rolling contact of the convex valve seat interface with the concave tunable valve seat mating surface is intentionally relatively low. Thus, the rolling action, when present, minimizes wear that might otherwise be associated with substantially sliding contact of these surfaces. Further, when rolling contact between valve body and tunable valve seat is present during both longitudinal valve body flexure and the elastic rebound which follows, trapping of particulate matter from the pumped fluid between the rolling surfaces tends to be minimized.
[0139] Summarizing, an example invention embodiment includes a tunable check valve assembly in a fluid end for high pressure pumping, the fluid end having at least one fluid end resonant frequency. The tunable check valve assembly comprises a plurality of radially-spaced vibration dampers disposed in a valve body, wherein at least one vibration damper has at least a first predetermined assembly resonant frequency similar to at least one fluid end resonant frequency. Further, the valve body comprises a peripheral valve seat interface having a convex curvature. The valve seat interface undergoes a substantially elastic concave flexure with slight circular rotation as the valve body seats against a valve seat having a concave mating surface with correspondingly less curvature than the peripheral valve seat interface and achieves a circular rolling contact with the mating surface of the valve seat.
[0140] An alternative invention embodiment includes a tunable valve seat in a fluid end for high pressure pumping, the fluid end having at least one fluid end resonant frequency. The tunable valve seat comprises a lateral support assembly longitudinally-spaced from a mating surface, the lateral support assembly for resiliently coupling the valve seat to a fluid end housing. The tunable valve seat has at least one seat resonant frequency similar to at least one fluid end resonant frequency; and the mating surface has a concave curvature that forms a circular rolling contact seal with a valve body as the valve body seats against the mating surface. The valve body has a convex peripheral valve seat interface of a correspondingly greater curvature than the mating surface; and the curvature of the mating surface causes the valve seat interface to undergo a substantially elastic concave flexure with slight circular rotation to form the circular rolling contact seal.
[0141] Since rolling contact takes place over a finite time interval, it also assists in smoothly redirecting pumped fluid momentum laterally and proximally. Forces due to oppositely directed radial components of the resultant fluid flow tend to cancel, and energy lost in pumped fluid turbulence is subtracted (as heat) from that of the valve-closure energy impulse, thus decreasing both its amplitude and the amplitude of associated vibration.
[0142] In addition to the above described energy dissipation (associated with hysteresis secondary to valve body flexure), hysteresis loss will also occur during pressure-induced movements of the viscoelastic groove element (in association with the valve seal function). Note that pumped fluid pressure acting on a valve comprising an embodiment of the invention's tunable check valve assembly may hydraulically pressurize substantially all of the viscoelastic elements in a tunable check valve assembly. Although polymers suitable for use in the viscoelastic elements generally are relatively stiff at room ambient pressures and temperatures, the higher pressures and temperatures experienced during pump pressure strokes tend to cause even relatively stiff polymers to behave like fluids which can transmit pressure hydraulically. Thus, a viscoelastic element in a peripheral seal-retention groove is periodically hydraulically pressurized, thereby increasing its sealing function during the high-pressure portion of the pump cycle. Hydraulic pressurization of the same viscoelastic element is reduced during the low-pressure portion of the pump cycle when the sealing function is not needed.
[0143] Because of the above-described energy loss and the time required for valve body longitudinal deformation to take place, with the associated dissipation of closing impulse energy described above, a valve-closure energy impulse applied to a tunable check valve assembly or tunable radial array is relatively lower in amplitude and longer in duration (e.g., secondary to having a longer rise time) than an analogous valve-closure energy impulse applied to a conventionally stiff valve body which closes on a conventional frusto-conical valve seat. The combination of lower amplitude and increased duration of the valve-closure energy impulse results in a narrowed characteristic vibration bandwidth having reduced potential for induction of damaging resonances in the valve, valve seat, and adjacent portions of the pump housing. See, e.g., the above-cited '242 patent.
[0144] Note that in describing the fluid-like behavior of certain polymers herein under elevated heat and pressure, the term “polymer” includes relatively homogenous materials (e.g., a single-species fluid polymer) as well as composites and combination materials containing one or more of such relatively homogenous materials plus finely divided particulate matter (e.g., nanoparticles) and/or other dispersed species (e.g., species in colloidal suspension, graphene) to improve heat scavenging and/or other properties. See, e.g., U.S. Pat. No. 6,432,320 B1, incorporated by reference.
[0145] In addition to heat scavenging, damping is a function of the viscoelastic elements in various embodiments of the invention. Optimal damping is associated with relatively high storage modulus and loss tangent values, and is obtained over various temperature ranges in multicomponent systems described as having macroscopically phase-separated morphology, microheterogeneous morphology, and/or at least one interpenetrating polymer network. See, e.g., the above-cited '006 patent and U.S. Pat. Nos. 5,091,455; 5,238,744; 6,331,578 B1; and 7,429,220 B2, all incorporated by reference.
[0146] Summarizing salient points of the above description, recall that vibration attenuation and damping in a tunable check valve assembly, tunable valve seat, tunable plunger seal, or tunable radial array of the invention operate via four interacting mechanisms. First, impulse amplitude is reduced by converting a portion of total closing impulse energy to heat (e.g., via hysteresis and fluid turbulence), which is then ultimately rejected to the check valve body surroundings (e.g., the pumped fluid). Each such reduction of impulse amplitude means lower amplitudes in the characteristic vibration spectrum transmitted to the pump housing.
[0147] Second, the closing energy impulse as sensed at the valve seat is reshaped in part by lengthening the rebound cycle time (estimated as the total time associated with peripheral valve seal compression, concave valve body flexure and elastic rebound). Such reshaping may in general be accomplished using mechanical/hydraulic/pneumatic analogs of electronic wave-shaping techniques. In particular, lengthened rebound cycle time is substantially influenced by the valve body's increased longitudinal compliance associated with the rolling contact/seal and concave valve body flexure described herein between valve body and valve seat. The units of lengthened cycle times are seconds, so their inverse functions have dimensions of per second (or 1/sec), the same dimensions as frequency. Thus, as noted above, the inverse function is termed herein characteristic rebound frequency.
[0148] Lowered characteristic rebound frequency (i.e., increased rebound cycle time) corresponds to slower rebound, with a corresponding reduction of the impulse's characteristic bandwidth due to loss of higher frequency content. This condition is created during impulse hammer testing by adding to hammer head inertia and by use of softer impact tips (e.g., plastic tips instead of the metal tips used when higher frequency excitation is desired). In contrast, tunable check valve assemblies and tunable radial arrays achieve bandwidth narrowing (and thus reduction of the damage potential of induced higher-frequency vibrations) at least in part through increased longitudinal compliance. In other words, bandwidth narrowing is achieved in embodiments of the invention through an increase of the effective impulse duration (as by, e.g., slowing the impulse's rise time and/or fall time as the valve assembly's components flex and relax over a finite time interval).
[0149] Third, induced vibration resonances of the tunable check valve assembly, tunable valve seat, and/or other tunable components are effectively damped by interactions generating structural hysteresis loss. Associated fluid turbulence further assists in dissipating heat energy via the pumped fluid.
[0150] And fourth, the potential for excitation of damaging resonances in pump vibration induced by a closing energy impulse is further reduced through narrowing of the impulse's characteristic vibration bandwidth by increasing the check valve body's effective inertia without increasing its actual mass. Such an increase of effective inertia is possible because a portion of pumped fluid moves with the valve body as it flexes and/or longitudinally compresses. The mass of this portion of pumped fluid is effectively added to the valve body's mass during the period of flexure/rebound, thereby increasing the valve body's effective inertia to create a low-pass filter effect (i.e., tending to block higher frequencies in the manner of an engine mount).
[0151] To increase understanding of the invention, certain aspects of tunable components (e.g., alternate embodiments and multiple functions of structural features) are considered in greater detail. Alternate embodiments are available, for example, in guide means known to those skilled in the art for maintaining valve body alignment within a (suction or discharge) bore. Guide means thus include, e.g., a central guide stem and/or a full-open or wing-guided design (i.e., having a distal crow-foot guide).
[0152] Similarly, alteration of a viscoelastic element's vibration pattern(s) in a tunable fluid end is addressed (i.e., tuned) via adjustable and/or time-varying constraints. Magnitude and timing of the constraints are determined in part by closing-impulse-related distortions and/or the associated vibration. For example, a viscoelastic reservoir (or central) element is at least partially constrained as it is disposed in the central annular reservoir, an unconstrained area optionally being open to pumped fluid pressure. That is, the viscoelastic reservoir element is at least partially constrained by relative movement of the interior surface(s) of the (optionally annular) reservoir, and further constrained by one or more structures (e.g., flanges) coupled to such surface(s). Analogously, a viscoelastic groove (or peripheral) element is at least partially constrained by relative movement of the groove walls, and further constrained by shear-thickening material within one or more circular tubular areas of the element (any of which may comprise a plurality of lumens).
[0153] Since the magnitude and timing of closing-impulse-related distortions are directly related to each closing energy impulse, the tunable fluid end's overall response is adaptive to changing pump operating pressures and speeds on a stroke-by-stroke basis. So for each set of operating parameters (e.g. cycle time and peak pressure for each pressure/suction stroke cycle), one or more of the constrained viscoelastic elements has at least a first predetermined assembly resonant frequency substantially similar to an instantaneous pump resonant frequency (e.g., a resonant frequency measured or estimated proximate the suction valve seat deck). And for optimal damping, one or more of the constrained viscoelastic elements may have, for example, at least a second predetermined assembly resonant frequency similar to the first predetermined assembly resonant frequency.
[0154] Note that the adaptive behavior of viscoelastic elements is beneficially designed to complement both the time-varying behavior of valves generating vibration with each punp pressure stroke, and the time-varying response of the fluid end as a whole to that vibration.
[0155] Note also that a tunable check valve assembly and/or tunable valve seat analogous to those designed for use in a tunable suction check valve may be incorporated in a tunable discharge check valve as well. Either a tunable suction check valve or a tunable discharge check valve or both may be installed in a pump fluid end housing. Additionally, one or more other tunable components may be combined with tunable suction and/or discharge check valves. A pump housing resonant frequency may be chosen as substantially equal to a first predetermined resonant frequency of each of the tunable components installed, or of any combination of the installed tunable components. Or the predetermined component resonant frequencies may be tuned to approximate different pump housing resonant frequencies as determined for optimal vibration damping.
[0156] For increased flexibility in accomplishing the above tuning, fenestrations may be present in the groove wall to accommodate radial tension members. At least a portion of each fenestration may have a transverse area which increases with decreasing radial distance to said longitudinal axis. That is, each fenestration flares to greater transverse areas in portions closer to the longitudinal axis, relative to the transverse areas of portions of the fenestration which are more distant from the longitudinal axis. Thus, a flared fenestration is partly analogous to a conventionally flared tube, with possible differences arising from the facts that (1) fenestrations are not limited to circular cross-sections, and (2) the degree of flare may differ in different portions of a fenestration. Such flares assist in stabilizing a viscoelastic groove element via a plurality of radial tension members.
[0157] Note that in addition to the example alternate embodiments described herein, still other alternative invention embodiments exist, including valves, pump housings and pumps comprising one or more of the example embodiments or equivalents thereof. Additionally, use of a variety of fabrication techniques known to those skilled in the art may lead to embodiments differing in detail from those schematically illustrated herein. For example, internal valve body spaces may be formed during fabrication by welding (e.g., inertial welding or laser welding) valve body portions together as in the above-cited '837 patent, or by separately machining such spaces with separate coverings. Valve body fabrication may also be by rapid-prototyping (i.e., layer-wise) techniques. See, e.g., the above-cited '057 patent. Viscoelastic elements may be cast and cured separately or in place in a valve body as described herein. See, e.g., U.S. Pat. No. 7,513,483 B1, incorporated by reference.
BRIEF DESCRIPTION OF THE DRAWINGS
[0158] FIG. 1 is a schematic 3-dimensional view of a partially sectioned tunable check valve assembly/tunable radial array embodiment showing how an adjustable preload flange constrains an area of the viscoelastic reservoir element as described herein.
[0159] FIG. 2 includes a schematic 3-dimensional exploded view of the tunable check valve assembly/tunable radial array embodiment of FIG. 1 showing viscoelastic body elements, the valve body, and the adjustable preload flange.
[0160] FIG. 3 is a schematic 3-dimensional partially-sectioned view of viscoelastic reservoir, groove and fenestration elements (i.e., viscoelastic body elements) of FIGS. 1 and 2 showing the constrained area of the reservoir element where it contacts an adjustable preload flange, as well as an adjacent unconstrained area.
[0161] FIG. 4 is a schematic 3-dimensional partially-sectioned view of two check valve bodies with an adjustable preload flange located at different longitudinal positions on a central guide stem.
[0162] FIG. 5 is a schematic 3-dimensional instantaneous partially-sectioned view of shear-thickening material which would, e.g., substantially fill a circular tubular area in a viscoelastic groove element, a support circular tubular area of a tunable valve seat, a tunable plunger seal, or a tunable resilient circumferential seal.
[0163] FIG. 6 is a schematic illustration of an exploded partially-sectioned 2-dimensional view of major components of a pump fluid end subassembly. Brief explanatory comments on component functions are found in the detailed description. The schematically-illustrated subassembly comprises a pumping chamber within a subassembly pump housing, the pumping chamber being in fluid communication with a suction bore, a discharge bore, and a piston/plunger bore. Schematic representations of a suction check valve, a discharge check valve, and a piston/plunger are shown in their respective bores.
[0164] FIG. 7 is a schematic illustration of two views of an exploded partially-sectioned 3-dimensional view of a valve body and tunable valve seat embodiment. Curved longitudinal section edges of the valve body's convex valve seat interface and corresponding concave mating portions of the tunable valve seat are shown schematically in a detail breakout view to aid description herein of a rolling valve seal along a circular line. A tunable (suction or discharge) check valve embodiment of the invention may comprise a combination of a tunable check valve assembly/tunable radial array (see, e.g., FIGS. 1 and 2 ) and a tunable valve seat (see, e.g., FIGS. 7 and 8 ).
[0165] FIG. 8 is a schematic 3-dimensional exploded and partially-sectioned view of a tunable valve seat embodiment showing a concave mating surface longitudinally spaced apart from a lateral support mounting surface, and an adjustable lateral support assembly comprising first and second securable end spacers in combination with a plurality of circular viscoelastic support elements, each support element comprising a support circular tubular area.
[0166] FIG. 9 is a schematic 3-dimensional exploded view of a partially sectioned tunable check valve assembly embodiment. A dilatant (i.e., shear-thickening) liquid is schematically shown being added to a check valve body's internal cavity, the cavity being shown as enclosing a tuned vibration damper comprising discrete mechanical elements (e.g., a mass and three springs).
[0167] FIG. 10 is a schematic 3-dimensional exploded view of a tunable check valve embodiment comprising the tunable check valve assembly of FIG. 9 together with a tunable valve seat, the tunable check valve embodiment including structures to facilitate a rolling seal along a circular line between the valve body's valve seat interface and the tunable valve seat's mating surface. Note that the (convex) valve seat interface has correspondingly greater curvature than the (concave) mating surface, and the mating surface has correspondingly less curvature than the valve seat interface.
[0168] FIG. 11 is a schematic 3-dimensional exploded view of an alternate tunable check valve embodiment comprising the tunable check valve assembly of FIG. 9 together with a tunable valve seat, the tunable check valve embodiment including structures to facilitate a rolling seal along a circular line between the check valve body's peripheral valve seat interface and the tunable valve seat's mating surface. An adjustable lateral support assembly is shown with the tunable valve seat, the assembly comprising first and second securable end spacers in combination with a plurality of circular viscoelastic support elements, each support element shown in a detail breakout view as comprising a support circular tubular area.
[0169] FIG. 12 illustrates longitudinal sections of two schematic 3-dimensional views of an alternate tunable check valve assembly embodiment comprising a plurality of radially-spaced vibration dampers disposed in a valve body having a peripheral seal. Each vibration damper comprises a circular tubular area, and at least one vibration damper is tunable via a fluid tuning medium in a tubular area. A central fluid tuning medium is shown schematically being added to the central circular tubular area. A fluid tuning medium may comprise, e.g., one or more shear-thickening materials.
[0170] FIG. 13 includes more-detailed longitudinal sections of a schematic 3-dimensional exploded view analogous-in-part to that of the alternate tunable check valve assembly embodiment of FIG. 12 . Detail breakout views include the peripheral seal's medial flange and the medial flange's corresponding flange channel. An instantaneous schematic view of a peripheral fluid tuning medium in the peripheral seal's circular tubular area is shown separately, and a central fluid tuning medium is shown schematically being added to the central circular tubular area. Note that a portion of the peripheral circular tubular area (with its fluid tuning medium) extends into (i.e., is partially surrounded by) the peripheral seal's medial flange. The central and peripheral circular tubular areas, with their respective fluid tuning media, constitute a plurality of tunable vibration dampers in the form of a tunable radial array.
[0171] FIG. 14A illustrates longitudinal sections of a partial schematic 3-dimensional view of an alternate tunable check valve embodiment comprising the tunable valve body shown as part of the exploded assembly in FIG. 13 , together with a tunable valve seat 450 . Note that tapered mounting surface 452 interfaces with a fluid end housing in which tunable valve seat 450 may be mounted. A detail breakout view shows that peripheral valve seat interface 434 is convex, having correspondingly greater curvature than tunable valve seat concave mating surface 454 . The concave mating surface has correspondingly less curvature than the peripheral valve seat interface to facilitate a circular rolling contact seal providing decreased contact area substantially along a circular line between the valve body's peripheral valve seat interface and the tunable valve seat's concave mating surface.
[0172] FIG. 14B illustrates longitudinal sections of a partial schematic 3-dimensional view of an alternate tunable check valve embodiment comprising the tunable check valve assembly embodiment of FIG. 13 (having a first plurality of tunable vibration dampers), together with a tunable valve seat (having a second plurality of tunable vibration dampers). The tunable valve seat of FIG. 14B comprises a plurality of tunable vibration-damping structural features comprising a concave mating surface and an adjustable lateral support assembly. The lateral support assembly interfaces with a fluid end housing in which tunable valve seat 450 ′ may be mounted, creating tunable coupling to the fluid end housing which differs from the coupling provided via tapered mounting surface 452 (see FIG. 14A ).
[0173] FIG. 15 illustrates a partial schematic 3-dimensional view of a tunable hydraulic stimulator embodiment comprising a hammer element longitudinally movable within a hollow cylindrical housing having a longitudinal axis, one end of the housing being closed by a fluid interface, and the other end being closed by a driver element. The fluid interface is shown with a MEMS accelerometer for detecting vibration of the interface.
[0174] FIG. 16A illustrates a partial schematic 3-dimensional exploded view of the tunable hydraulic stimulator embodiment of FIG. 15 , a first electrical cable being shown to schematically indicate a feedback path (for an accelerometer signal) from the accelerometer to the driver element. A second electrical cable is shown to schematically indicate an interconnection path for, e.g., communication with one or more additional stimulators and/or associated equipment such as a programmable controller.
[0175] FIG. 16B illustrates a schematic 3-dimensional exploded view of an adaptive stimulator embodiment that differs from the embodiment of FIGS. 15 and 16A in part because it comprises a fluid interface comprising three disc-shaped thin members. Electrical leads signify that each disc-shaped thin member can function as a vibration detector, and electrical leads also draw attention to an electromagnetic hammer driver and a peripheral transverse coil for creating a stepwise adjustable steady-state longitudinal magnetic field.
[0176] FIG. 17 schematically illustrates a 2-dimensional view of major components, subsystems, and interconnections of an adaptive down-hole stimulation system embodiment, together with brief explanatory comments on component and subsystem functions. As aids to orientation, a schematic wellbore is shown, as are control link pathways for communication among pumps, tunable down-hole stimulator(s) and a tunable down-hole stimulation system controller. Schematic pathways are shown for stimulation vibration energy directed toward down-hole geologic material adjacent to the wellbore, and for backscatter vibration energy emanating from the stimulated geologic material.
[0177] FIG. 18 schematically illustrates an embodiment of an adaptive down-hole stimulation system embodiment analogous in part to that of FIG. 17 . Portions of the illustration of FIG. 18 resemble analogous portions of FIG. 17 . But structural and functional differences between the systems of FIGS. 17 and 18 include replacement of a single tunable down-hole stimulator (in FIG. 17 ) with a linear array of three tunable down-hole stimulators (in FIG. 18 ). Further, power spectral densities (PSD's) of impulse-generated vibration from each stimulator of FIG. 18 may be adjusted for stimulation comprising resonance excitation, fracturing and/or analysis of geologic materials. A frac pump producing cyclically-varying down-hole pressure provides for such stimulation at varying distances from a wellbore. And appropriate timing of stimulation vibration bursts from each stimulator facilitates directional propagation of combined vibration wave fronts. Further, relative shifts (i.e., discrete time intervals and/or phase relationships) among timed stimulator transmission signals, timed stimulator shift signals and/or timed pressure signals may be controlled via a programmable controller.
DETAILED DESCRIPTION
[0178] Tunable equipment associated with high-pressure well-stimulation comprises tunable down-hole stimulators (plus associated controllers, power supplies, etc.). Frac and/or proppant pumps optionally comprise tunable fluid ends (which include but are not limited to, e.g., tunable valve assemblies and/or vibration dampers) which facilitate selective attenuation of valve-generated vibration at or near its source to reduce fluid end fatigue failures. Tunable down-hole stimulation systems includes system controllers plus single or multiple tunable hydraulic stimulators, with optional inclusion of tunable fluid ends. FIGS. 1-16 relate to components and subsystems, while FIGS. 17 and 18 schematically illustrate various embodiments of down-hole stimulation systems.
[0179] FIGS. 1-14B schematically illustrate how adding multifunction rings, tunable valve seats, tunable radial arrays and/or plunger seals to tunable check valve assemblies in a fluid end further facilitates optimal damping and/or selective attenuation of vibration at one or more predetermined (and frequently-localized) fluid end resonant frequencies.
[0180] A tunable (suction or discharge) check valve of the invention may comprise, for example, a combination of a tunable check valve assembly/tunable radial array 99 (see, e.g., FIG. 1 ) and a tunable valve seat 20 or a tunable valve seat 389 (see, e.g., FIGS. 7 and 11 ). Details of the structure and functions of each component are provided herein both separately and as combined with other components to obtain synergistic benefits contributing to longer pump service life.
[0181] FIGS. 1 and 2 schematically illustrate an invention embodiment of a tunable check valve assembly/tunable radial array 99 substantially symmetrical about a longitudinal axis. Illustrated components include a valve body 10 , an adjustable preload flange 30 , and a plurality of viscoelastic body elements 50 . Check valve body 10 , in turn, comprises a peripheral groove 12 (see FIG. 2 ) spaced apart by an annular (central) reservoir 16 from a longitudinal guide stem 14 , groove 12 being responsive to longitudinal compressive force. A plurality of viscoelastic body elements 50 comprises an annular (central) reservoir element 52 coupled to a (peripheral) groove element 54 by a plurality of (optional) radial fenestration elements 56 (in fenestrations 18 ) to form a tunable radial array. Groove element 54 functions as a vibration damper and valve seal, comprising at least one circular tubular area 58 .
[0182] Responsiveness of groove 12 to longitudinal compressive force is characterized in part by damping of groove wall 11 / 13 / 15 vibrations. Such damping is due in part to out-of-phase vibrations in proximal groove wall 13 and distal groove wall 11 which are induced by longitudinal compressive force. Such out-of-phase vibrations will cause various groove-related dimensions to vary with longitudinal compressive force, thereby indicating the responsiveness of groove 12 to such force (see, for example, the dimension labeled A in FIG. 2 ). Each phase shift, in turn, is associated with differences in the coupling of proximal groove wall 13 to guide stem 14 (indirectly via longitudinal groove wall 15 and radial reservoir floor 19 ) and the coupling of distal groove wall 11 to guide stem 14 (directly via radial reservoir floor 19 ). Note that longitudinal groove wall 15 may comprise fenestrations 18 , thereby increasing the responsiveness of groove 12 to longitudinal compressive force on tunable check valve assembly 99 .
[0183] Referring to FIGS. 1-3 , adjustable preload flange 30 extends radially from guide stem 14 (toward peripheral reservoir wall 17 ) over, for example, about 20% to about 80% of viscoelastic reservoir element 52 (see FIG. 3 ). Adjustable preload flange 30 thus imposes an adjustable annular shear preload over an annular constrained area 62 of viscoelastic reservoir element 52 to achieve at least a first predetermined assembly resonant frequency substantially replicating a (similar) measured or estimated resonant frequency (e.g., a pump housing resonant frequency). Note that an adjacent annular unconstrained area 60 of viscoelastic reservoir element 52 remains open to pumped fluid pressure. Note also that adjustable preload flange 30 may be adjusted in effective radial extent and/or longitudinal position.
[0184] Note further that annular constrained area 62 and annular unconstrained area 60 are substantially concentric and adjacent. Thus, for a tunable suction valve subject to longitudinal (i.e., distally-directed) compressive constraint applied via preload flange 30 to annular constrained area 62 , annular unconstrained area 60 will tend to move (i.e., extrude) proximally relative to area 62 . The oppositely-directed (i.e., countercurrent) movements of constrained and unconstrained annular areas of viscoelastic reservoir element 52 create a substantially annular area of shear stress.
[0185] Finally, each circular tubular area 58 is substantially filled with at least one shear-thickening material 80 (see FIG. 5 ) chosen to achieve at least a second predetermined assembly resonant frequency similar, for example, to the first predetermined assembly resonant frequency). Note that FIG. 5 schematically represents a partially-sectioned view of an instantaneous configuration of the shear-thickening material 80 within circular tubular area 58 .
[0186] Referring to FIGS. 1 and 2 in greater detail, a tunable check valve assembly/tunable radial array embodiment 99 comprises viscoelastic body elements 50 which comprise, in turn, reservoir (central) element 52 coupled to groove (peripheral) element 54 via radial fenestration (tension) elements 56 . Elements 52 , 54 and 56 are disposed in (i.e., integrated with and/or lie substantially in) reservoir 16 , groove 12 and fenestrations 18 respectively to provide a tuned radial array having at least a third predetermined resonant frequency. An adjustable preload flange 30 is coupled to guide stem 14 and contacts viscoelastic reservoir element 52 in reservoir 16 to impose an adjustable annular constraint on viscoelastic reservoir element 52 for achieving at least a first predetermined assembly resonant frequency substantially similar to, for example, a measured resonant frequency (e.g., a pump housing resonant frequency). Such adjustable annular constraint imposes an adjustable shear preload between constrained annular area 62 and unconstrained annular area 60 . Tunable check valve assembly 99 may additionally comprise at least one circular tubular area 58 in groove element 54 residing in groove 12 , each tubular area 58 being substantially filled with at least one shear-thickening material 80 chosen to achieve at least a second predetermined assembly resonant frequency similar, for example, to the first predetermined assembly resonant frequency).
[0187] The above embodiment may be installed in a pump housing having a measured housing resonant frequency; the measured housing resonant frequency may then be substantially replicated in the (similar) first predetermined resonant frequency of the tunable check valve assembly. Such a combination would be an application of an alternate embodiment. An analogous tuning procedure may be followed if the tunable check valve assembly of the second embodiment is installed in a pump having a (similar or different) resonant frequency substantially equal to the second predetermined resonant frequency. This synergistic combination would broaden the scope of the valve assembly's beneficial effects, being yet another application of the invention's alternate embodiment.
[0188] Note that preload flange 30 may have a non-cylindrical periphery 32 for imposing on viscoelastic reservoir element 52 an adjustable annular shear preload having both longitudinal and transverse components.
[0189] Note further that the periphery of adjustable preload flange 30 , if cylindrical, predisposes a tunable check valve assembly to substantially longitudinal shear damping with each longitudinal distortion of check valve body 10 associated with valve closure. The character of such shear damping depends, in part, on the longitudinal position of the preload flange. Examples of different longitudinal positions are seen in FIG. 4 , which schematically illustrates the flange 30 ′ longitudinally displaced from flange 30 ″. Further, as shown in FIG. 4 , the convex periphery of a longitudinally adjusted preload flange 30 ′ or 30 ″ may introduce shear damping of variable magnitude and having both longitudinal and transverse components. Such damping may be beneficial in cases where significant transverse valve-generated vibration occurs.
[0190] To clarify the placement of viscoelastic body elements 50 , labels indicating the portions are placed on a sectional view in FIGS. 2 and 3 . Actual placement of viscoelastic body elements 50 in valve body 10 (see FIG. 1 ) may be by, for example, casting viscoelastic body elements 50 in place, or placing viscoelastic body elements 50 (which have been precast) in place during layer-built or welded fabrication. The tunable check valve assembly embodiment of the invention is intended to represent check valve body 10 and viscoelastic body elements 50 as complementary components at any stage of manufacture leading to functional integration of the two components.
[0191] To enhance scavenging of heat due to friction loss and/or hysteresis loss, shear-thickening material 80 and/or viscoelastic body elements 50 may comprise one or more polymers which have been augmented with nanoparticles and/or graphene 82 (see, e.g., FIG. 5 ). Nanoparticles and/or graphene may be invisible to the eye as they are typically dispersed in a colloidal suspension. Hence, they are schematically represented by cross-hatching 82 in FIG. 5 . Nanoparticles may comprise, for example, carbon forms (e.g., graphene) and/or metallic materials such as copper, beryllium, titanium, nickel, iron, alloys or blends thereof. The term nanoparticle may conveniently be defined as including particles having an average size of up to about 2000 nm. See, e.g., the '320 patent.
[0192] FIG. 6 is a schematic illustration of an exploded partially-sectioned 2-dimensional view of major components of a pump fluid end subassembly 88 , together with graphical aids and brief explanatory comments on component functions. The schematically-illustrated subassembly 88 comprises a pumping chamber 74 within a subassembly (pump) housing 78 , the pumping chamber 74 being in fluid communication with a suction bore 76 , a discharge bore 72 , and a piston/plunger bore 70 . Note that piston/plunger bore 70 comprises at least one recess (analogous to that labeled “packing box” in FIG. 6 ) in which at least one lateral support assembly 130 (see FIG. 8 ) may be sealingly positionable along the plunger as part of a tunable plunger seal embodiment. Schematic representations of a tunable suction valve 95 (illustrated for simplicity as a hinged check valve), a tunable discharge valve 97 (also illustrated for simplicity as a hinged check valve), and a piston/plunger 93 (illustrated for simplicity as a plunger) are shown in their respective bores. Note that longitudinally-moving valve bodies in check valve embodiments schematically illustrated herein (e.g., valve body 10 ) are associated with certain operational phenomena analogous to phenomena seen in hinged check valves (including, e.g., structural compliance secondary to closing energy impulses).
[0193] Regarding the graphical aids of FIG. 6 , the double-ended arrows that signify fluid communication between the bores (suction, discharge and piston/plunger) and the pumping chamber are double-ended to represent the fluid flow reversals that occur in each bore during each transition between pressure stroke and suction stroke of the piston/plunger. The large single-ended arrow within the pumping chamber is intended to represent the periodic and relatively large, substantially unidirectional fluid flow from suction bore through discharge bore during pump operation.
[0194] Further regarding the graphical aids of FIG. 6 , tunable suction (check) valve 95 and tunable discharge (check) valve 97 are shown schematically as hinged check valves in FIG. 6 because of the relative complexity of check valve embodiments having longitudinally-moving valve bodies. More detailed schematics of several check valve assemblies and elements are shown in FIGS. 1-11 , certain tunable check valve embodiments comprising a tunable check valve assembly and a tunable valve seat. In general, the tunable check valve assemblies/tunable radial arrays of tunable suction and discharge valves will typically be tuned to different assembly resonant frequencies because of their different positions in a subassembly housing 78 (and thus in a pump housing as described herein). Pump housing resonant frequencies that are measured proximate the tunable suction and discharge valves will differ in general, depending on the overall pump housing design. In each case they serve to guide the choices of the respective assembly resonant frequencies for the valves.
[0195] Note that the combination of major components labeled in FIG. 6 as a pump fluid end subassembly 88 is so labeled (i.e., is labeled as a subassembly) because typical fluid end configurations comprise a plurality of such subassemblies combined in a single machined block. Thus, in such typical (multi-subassembly) pump fluid end designs, as well as in less-common single-subassembly pump fluid end configurations, the housing is simply termed a “pump housing” rather than the “subassembly housing 78 ” terminology of FIG. 6 .
[0196] Further as schematically-illustrated and described herein for clarity, each pump fluid end subassembly 88 comprises only major components: a pumping chamber 74 , with its associated tunable suction valve 95 , tunable discharge valve 97 , and piston/plunger 93 in their respective bores 76 , 72 and 70 of subassembly housing 78 . For greater clarity of description, common fluid end features well-known to those skilled in the art (such as access bores, plugs, seals, and miscellaneous fixtures) are not shown. Similarly, a common suction manifold through which incoming pumped fluid is distributed to each suction bore 76 , and a common discharge manifold for collecting and combining discharged pumped fluid from each discharge bore 72 , are also well-known to those skilled in the art and thus are not shown.
[0197] Note that the desired check-valve function of tunable check valves 95 and 97 schematically-illustrated in FIG. 6 requires interaction of the respective tunable check valve assemblies (see, e.g., FIGS. 1-5 ) with a corresponding (schematically-illustrated) tunable valve seat (see, e.g., FIGS. 7, 8, 10 and 11 ). The schematic illustrations of FIG. 6 are only intended to convey general ideas of relationships and functions of the major components of a pump fluid end subassembly. Structural details of the tunable check valve assemblies that are in turn part of tunable check valves 95 and 97 of the invention (including their respective tunable valve seats) are illustrated in greater detail in other figures as noted above. Such structural details facilitate a plurality of complementary functions that are best understood through reference to FIGS. 1-5 and 7-11 .
[0198] The above complementary functions of tunable check valves include, but are not limited to, closing energy conversion to heat via structural compliance, energy redistribution through rejection of heat to the pumped fluid and pump housing, vibration damping and/or selective vibration spectrum narrowing through changes in tunable check valve assembly compliance, vibration frequency down-shifting (via decrease in characteristic rebound frequency) through increase of rebound cycle time, and selective vibration attenuation through energy dissipation (i.e., via redistribution) at predetermined assembly resonant frequencies.
[0199] FIG. 7 is a schematic illustration of two views of an exploded partially-sectioned 3-dimensional view including a check valve body 10 and its convex valve seat interface 22 , together with concave mating surface 24 of tunable valve seat 20 . Mating surface 24 is longitudinally spaced apart from a pump housing interface surface 21 . A curved longitudinal section edge 28 of the tunable valve seat's mating surface 24 , together with a correspondingly greater curved longitudinal section edge 26 of the valve body's valve seat interface 22 , are shown schematically in detail view A to aid description herein of a rolling valve seal.
[0200] In summary, the valve body comprises a peripheral valve seat interface having a convex curvature. The valve seat interface undergoes a substantially elastic concave flexure with slight circular rotation as the valve body seats against a valve seat having a concave mating surface with correspondingly less curvature than the peripheral valve seat interface. As a result, the peripheral valve seat interface achieves a circular rolling contact with the mating surface of the valve seat.
[0201] Alternatively, the valve seat mating has a concave curvature that forms a circular rolling contact seal with a valve body as the valve body seats against the mating surface. The valve body has a convex peripheral valve seat interface with a correspondingly greater curvature than the mating surface. And the curvature of the mating surface causes the valve seat interface to undergo a substantially elastic concave flexure with slight circular rotation to form the circular rolling contact seal.
[0202] The correspondingly greater curvature of valve seat interface 22 , as compared to the curvature of mating surface 24 , effectively provides a rolling seal against fluid leakage which reduces wear on the surfaces in contact. The rolling seal also increases longitudinal compliance of a tunable suction or discharge valve of the invention, with the added benefit of increasing the rise and fall times of the closing energy impulse (thus narrowing the associated vibration spectrum). Widening the closing energy impulse increases rebound cycle time and correspondingly decreases characteristic rebound frequency.
[0203] Further regarding the terms “correspondingly greater curvature” or “correspondingly less curvature” as used herein, note that the curvatures of the schematically illustrated longitudinal section edges (i.e., 26 and 28 ) and the surfaces of which they are a part (i.e., valve seat interface 22 and mating surface 24 respectively) are chosen so that the degree of longitudinal curvature of valve seat interface 22 (including edge 26 ) exceeds that of (i.e., has correspondingly greater curvature than) mating surface 24 (including edge 28 ) at any point of rolling contact. In other words, mating surface 24 (including edge 28 ) has correspondingly less curvature than valve seat interface 22 (including edge 26 ). Hence, rolling contact (i.e., a rolling valve seal) between valve seat interface 22 and mating surface 24 is along a substantially circular line (i.e., mating surface 24 is a curved mating surface for providing decreased contract area along the circular line). The plane of the circular line is generally transverse to the (substantially coaxial) longitudinal axes of valve body 10 and tunable valve seat 20 . And the decreased contract area along the circular line is so described because it is small relative to the nominal contact area otherwise provided by conventional (frusto-conical) valve seat interfaces and valve seat mating surfaces.
[0204] Note that the nominal frusto-conical contact area mentioned above is customarily shown in engineering drawings as broad and smooth. But the actual contact area is subject to unpredictable variation in practice due to uneven distortions (e.g., wrinkling) of the respective closely-aligned frusto-conical surfaces under longitudinal forces that may exceed 250,000 pounds. An advantage of the rolling valve seal along a substantially circular line as described herein is minimization of the unpredictable effects of such uneven distortions of valve seat interfaces and their corresponding mating surfaces.
[0205] Note also that although valve seat interface 22 and mating surface 24 (and other valve seat interface/mating surface combinations described herein) are schematically illustrated as curved, either may be frusto-conical (at least in part) in certain tuned component embodiments. Such frusto-conical embodiments may have lower fabrication costs and may exhibit suboptimal distortion, down-shifting performance and/or wear characteristics. They may be employed in relatively lower-pressure applications where other tunable component characteristics provide sufficient operational advantages in vibration control.
[0206] The above discussion of rolling contact applies to the alternate tunable valve seat 20 ′ of FIG. 8 , as it does to the tunable valve seat 20 of FIG. 7 . FIG. 8 schematically illustrates a 3-dimensional exploded and partially-sectioned view of a tunable valve seat showing a mating surface (analogous to mating surface 24 of FIG. 7 ) longitudinally spaced apart from a lateral support mounting surface 21 ′. But the lateral support mounting surface 21 ′ in FIG. 8 differs from pump housing interface surface 21 of FIG. 7 in that it facilitates adjustably securing a lateral support assembly 130 to alternate tunable valve seat 20 ′. Lateral support assembly 130 comprises first and second securable end spacers ( 110 and 124 respectively) in combination with a plurality of circular viscoelastic support elements ( 114 , 118 and 122 ), each support element comprising a support circular tubular area (see areas 112 , 116 and 120 respectively). Shear-thickening material in each support circular tubular area 112 , 116 and 120 is chosen so each lateral support assembly 130 has at least one predetermined resonant frequency. Lateral support assemblies thus configured may be part of each tunable valve seat and each tunable plunger seal. When part of a tunable plunger seal, one or more lateral support assemblies 130 reside in at least one recess analogous to the packing box schematically illustrated adjacent to piston/plunger 93 (i.e., as a portion of piston/plunger bore 70 ) in FIG. 6 .
[0207] Note also that in general, a tunable (suction or discharge) check valve of the invention may comprise a combination of a tunable check valve assembly 99 (see, e.g., FIG. 1 ) and a tunable valve seat 20 (see, e.g., FIG. 7 ) or a tunable valve seat 20 ′ (see, e.g., FIG. 8 ). Referring more specifically to FIG. 6 , tunable suction check valve 95 is distinguished from tunable discharge check valve 97 by one or more factors, including each measured resonant frequency to which each tunable check valve is tuned so as to optimize the overall effectiveness of valve-generated vibration attenuation in the associated pump housing 78 .
[0208] FIGS. 9-11 show schematic exploded views of a nonlinear spring-mass damper 227 / 228 / 229 / 230 , which may be incorporated in a tunable check valve assembly embodiment 210 . FIGS. 9-11 can each be understood as schematically illustrating a tunable check valve assembly with or without a peripheral groove viscoelastic element. That is, each figure may also be understood to additionally comprise a viscoelastic groove element analogous to groove element 54 (see FIG. 2 ) residing in groove 218 ′/ 218 ″ (see FIG. 9 )—this groove element is not shown in exploded FIGS. 9-11 for clarity, but may be considered to comprise at least one circular tubular area analogous to tubular area 58 in groove element 54 (see FIG. 2 ), each tubular area 58 being substantially filled with at least one shear-thickening material 80 chosen to achieve at least one predetermined assembly resonant frequency.
[0209] Referring to FIG. 9 , Belleville springs 227 / 228 / 229 are nonlinear, and they couple mass 230 to the valve body base plate 216 and the proximal valve body portion 214 . Additionally, dilatant liquid 242 is optionally added (via sealable ports 222 and/or 220 ) to central internal cavity 224 to immerse nonlinear spring-mass damper 227 / 228 / 229 / 230 . The nonlinear behavior of dilatant liquid 242 in shear (as, e.g., between Belleville springs 227 and 228 ) expands the range of tuning the nonlinear spring-mass damper 227 / 228 / 229 / 230 to a larger plurality of predetermined frequencies to reduce “ringing” of valve body 214 / 216 in response to a closing energy impulse.
[0210] To clarify the function of nonlinear spring-mass damper 227 / 228 / 229 / 230 , mass 230 is shown perforated centrally to form a washer shape and thus provide a passage for flow of dilatant liquid 242 during longitudinal movement of mass 230 . This passage is analogous to that provided by each of the Belleville springs 227 / 228 / 229 by reason of their washer-like shape.
[0211] FIG. 10 shows an exploded view of an alternate embodiment of a tunable check valve comprising the tunable check valve assembly 210 of FIG. 9 , plus a tunable valve seat 250 . FIGS. 10 and 11 schematically illustrate two views of an exploded partially-sectioned 3-dimensional view including a valve body 214 / 216 and its valve seat interface 234 , together with mating surface 254 of tunable valve seats 250 and 250 ′. Mating surface 254 is longitudinally spaced apart from pump housing interface surface 252 in FIG. 10 , and from lateral support mounting surface 252 ′ in FIG. 11 . In FIG. 10 , a curved longitudinal section edge 256 of the tunable valve seat's mating surface 254 , together with a correspondingly greater curved longitudinal section edge 236 of valve seat interface 234 , are shown schematically to aid description herein of a rolling valve seal along a substantially circular line.
[0212] Note that valve body 214 / 216 may be fabricated by several methods, including that schematically illustrated in FIGS. 9-11 . For example, circular boss 215 on proximal valve body portion 214 may be inertia welded or otherwise joined to circular groove 217 on valve body base plate 216 . Such joining results in the creation of peripheral seal-retention groove 218 ′/ 218 ″ having proximal groove wall 218 ′ and distal groove wall 218 ″.
[0213] To enhance scavenging of heat due to friction loss and/or hysteresis loss, liquid polymer(s) 242 may be augmented by adding nanoparticles which are generally invisible to the eye as they are typically dispersed in a colloidal suspension. Nanoparticles comprise, for example, carbon and/or metallic materials such as copper, beryllium, titanium, nickel, iron, alloys or blends thereof. The term nanoparticle may conveniently be defined as including particles having an average size of up to about 2000 nm. See, e.g., the '320 patent.
[0214] The correspondingly greater curvature of valve seat interface 234 , as compared to the curvature of mating surface 254 , effectively provides a rolling seal against fluid leakage which reduces frictional wear on the surfaces in contact. The rolling seal also increases longitudinal compliance of a tunable suction or discharge valve of the invention, with the added benefit of increasing the rise and fall times of the closing energy impulse (thus narrowing the associated vibration spectrum).
[0215] Further regarding the term “correspondingly greater curvature” as used herein, note that the curvatures of the schematically illustrated longitudinal section edges (i.e., 236 and 256 ) and the surfaces of which they are a part (i.e., valve seat interface 234 and mating surface 254 respectively) are chosen so that the degree of longitudinal curvature of valve seat interface 234 (including edge 236 ) exceeds that of (i.e., has correspondingly greater curvature than) mating surface 254 (including edge 256 ) at any point of rolling contact. Hence, rolling contact between valve seat interface 234 and mating surface 254 is always along a substantially circular line that decreases contact area relative to the (potentially variable) contact area of a (potentially distorted) conventional frusto-conical valve body/valve seat interface (see discussion above). The plane of the circular line is generally transverse to the (substantially coaxial) longitudinal axes of valve body 214 / 216 and tunable valve seat 250 . (See notes above re frusto-conical valve seat interface shapes and mating surfaces).
[0216] The above discussion of rolling contact applies to the alternate tunable valve seat 250 ′ of FIG. 11 , as it does to the tunable valve seat 250 of FIG. 10 . But the lateral support mounting surface 252 ′ in tunable check valve 399 of FIG. 11 differs from pump housing interface surface 252 of FIG. 10 in that it facilitates adjustably securing a lateral support assembly 330 to alternate tunable valve seat 250 ′ to form tunable valve seat 389 . Lateral support assembly 330 comprises first and second securable end spacers ( 310 and 324 respectively) in combination with a plurality of circular viscoelastic support elements ( 314 , 318 and 322 ), each support element comprising a support circular tubular area ( 312 , 316 and 320 respectively).
[0217] Note that in general, a tunable (suction or discharge) check valve of the invention may comprise a combination of a tunable check valve assembly 210 (see, e.g., FIG. 9 ) and a tunable valve seat 250 (see, e.g., FIG. 10 ) or a tunable valve seat 250 ′ (see, e.g., FIG. 11 ). Referring more specifically to FIG. 6 , tunable suction valve 95 is distinguished from tunable discharge check valve 97 by one or more factors, including each measured or estimated resonant frequency to which each tunable check valve is tuned so as to optimize the overall effectiveness of valve-generated vibration attenuation in the associated pump housing 78 .
[0218] FIG. 12 illustrates two schematic 3-dimensional longitudinally-sectioned views of an alternate tunable check valve assembly embodiment comprising a plurality of radially-spaced vibration dampers disposed in a valve body 410 having a resilient peripheral seal 470 . Each of two radially-spaced vibration dampers comprises a circular tubular area (i.e., central circular tubular area 462 as seen in FIG. 12 , and peripheral circular tubular area 472 / 474 as seen in FIG. 13 ). Note that peripheral circular tubular area 472 / 474 is so designated because it comprises a lateral circular tubular portion 472 and a medial circular tubular portion 474 (see FIG. 13 ). And further note that at least one of the radially-spaced vibration dampers is tunable via a fluid tuning medium in a tubular area (see, e.g., in FIG. 12 that a central fluid tuning medium 442 is being added to spaces including central circular tubular area 462 ). A fluid tuning medium may comprise, e.g., one or more shear-thickening materials, and the medium may further comprise nanoparticles.
[0219] Thus, each vibration damper comprises a circular tubular area ( 462 / 472 ), and at least one vibration damper is tunable to a predetermined frequency (e.g., a resonant frequency of a fluid end in which the assembly is installed). The tuning mechanisms may differ: e.g., via a fluid medium 442 (shown schematically being added in FIG. 12 via a sealable port 422 in valve body 410 ) in a tubular area 462 and/or via a fluid medium 482 (shown as an instantaneous shape 480 ) within tubular area 472 . Control of variable fluid flow resistance and/or fluid stiffness (in the case of shear-thickening fluids) facilitates predetermination of resonant frequency or frequencies in the central and peripheral dampers.
[0220] In either case, tuning is function of responsiveness of the respective dampers to vibration secondary to valve closure impact (see above discussion of such impact and vibration). For example, longitudinal force on the closed valve will tend to reduce the distance between opposing fluid flow restrictors 466 / 468 , simultaneously prompting flow of fluid tuning medium 442 from circular tubular area 462 to areas 464 and/or 460 ( 460 acting as a surge chamber). Flow resistance will be a function of fluid flow restrictors 466 / 468 and the fluid viscosity. Note that viscosity may vary with time in a shear-thickening liquid 442 , thereby introducing nonlinearity for predictably altering center frequency and/or Q of the damper. Analogous predetermined viscosity variation in fluid tuning medium 482 is available for predictably altering the center frequency and/or Q (i.e., altering the tuning) of the peripheral damper 470 / 472 / 482 as the seal 470 distorts under the longitudinal load of valve closure.
[0221] Note that the peripheral seal vibration damper 470 / 472 / 482 comprises a medial flange 479 sized to closely fit within flange channel 419 of valve body 410 , and medial flange 419 partially surrounds circular tubular area 472 within said seal 470 . Those skilled in the art know that conventional peripheral seals tend to rotate within their retaining groove. The illustrated seal embodiment herein shows that such rotation will tend to be resisted by the combined action of medial flange 479 and flange channel 419 . Further, the portion of circular tubular area 472 partially surrounded by medial flange 419 will tend to stiffen medial flange 479 in a nonlinear manner when circular tubular area 472 contains a shear-thickening fluid tuning medium.
[0222] FIG. 13 is a more-detailed schematic 3-dimensional longitudinally-sectioned exploded view analogous-in-part to that of the alternate tunable check valve assembly embodiment of FIG. 12 . Detail breakout views include medial flange 479 of resilient peripheral seal 470 , as well as the medial flange's corresponding flange channel 419 . An instantaneous schematic view of peripheral fluid tuning medium 480 in the peripheral circular tubular area 472 / 474 is shown spaced apart in the exploded view of FIG. 13 . Note that the longitudinally-sectioned (instantaneous shape) schematic illustration of peripheral fluid tuning medium 480 comprises a lateral fluid tuning medium portion 482 corresponding to lateral circular tubular portion 472 . Analogously, a medial fluid tuning medium portion 484 corresponds to medial circular tubular portion 474 . Hence, peripheral fluid tuning medium 480 , which includes both lateral fluid tuning medium portion 482 and medial fluid tuning medium portion 484 , may be referred to herein as peripheral fluid tuning medium 482 / 484 .
[0223] A central fluid tuning medium 442 is shown schematically being added (see FIGS. 12 and 13 ) to spaces including central circular tubular area 462 (labeled in FIG. 12 ). Note in FIG. 13 that medial portion 474 of peripheral circular tubular area 472 / 474 (with its medial fluid tuning medium portion 484 ) extends into (i.e., is partially surrounded by) medial flange 479 of resilient peripheral seal 470 . The central and peripheral circular tubular areas ( 462 and 472 / 474 respectively), with their respective central and peripheral fluid tuning media ( 442 and 482 / 484 respectively), constitute a first plurality of tunable vibration dampers in the form of a tunable radial array comprising two radially-spaced vibration dampers.
[0224] FIG. 14A illustrates a schematic 3-dimensional longitudinally-sectioned view of an alternate tunable check valve assembly embodiment comprising the valve body 410 (also shown in FIGS. 12, 13 and 14B ), together with a tunable valve seat 450 . Note that tapered mounting surface 452 of tunable valve seat 450 is intended for interfacing with a fluid end housing in which tunable valve seat 450 may be mounted. Detail breakout view A of FIG. 14 A shows that peripheral valve seat interface 434 is convex, having correspondingly greater curvature (as shown more clearly in section edge 436 ) than the concave mating surface 454 (as shown more clearly in section edge 456 ). The concave mating surface 454 has correspondingly less curvature than peripheral valve seat interface 434 to facilitate a circular rolling contact seal providing decreased contact area substantially along a circular line between the valve body's peripheral valve seat interface 434 and the tunable valve seat's concave mating surface 454 . As noted above, the circular rolling contact seal also increases longitudinal compliance of a tunable suction or discharge valve of the invention, with the added benefit of increasing the rise and fall times of the closing energy impulse (thus widening the closing energy impulse and narrowing the associated vibration spectrum). Widening the closing energy impulse in the time domain is reflected in an increased rebound cycle time, with a corresponding decrease in characteristic rebound frequency. Rebound cycle time and characteristic rebound frequency may thus be tuned for optimal damping.
[0225] FIG. 14B illustrates a schematic 3-dimensional longitudinally-sectioned view of an alternate tunable check valve embodiment comprising the tunable check valve assembly embodiment of FIG. 13 (having the above-described first plurality of tunable vibration dampers), together with a tunable valve seat (the tunable valve seat having a second plurality of tunable vibration dampers). The tunable valve seat of FIG. 14B comprises a plurality of tunable vibration-damping structural features including, for example, tunable valve seat 450 ′ with a concave mating surface 454 (surface 454 also being present in tunable valve seat 450 ). Tunable valve seat 450 ′ has the prime designation due to the inclusion of an adjustable lateral support assembly 724 / 722 / 720 / 718 / 716 / 714 / 712 / 710 , the lateral support assembly not being present in tunable valve seat 450 . The lateral support assembly interfaces with a fluid end housing in which tunable valve seat 450 ′ may be mounted, creating tunable coupling to the fluid end housing which differs from the coupling provided via tapered mounting surface 452 (see FIG. 14A ).
[0226] Considering the first plurality of tunable vibration dampers in greater detail, alternate tunable check valve assembly embodiment 442 / 410 / 470 / 480 (see, e.g., FIG. 13 ) is symmetrical about a longitudinal axis and comprises a plurality of radially-spaced vibration dampers (i.e., a tunable radial array of vibration dampers). A first vibration damper (i.e., a peripheral damper) is in the resilient peripheral seal 470 with its peripheral circular tubular area 472 / 474 and enclosed peripheral fluid tuning medium 482 / 484 . Peripheral circular tubular area 472 / 474 is responsive to cyclical longitudinal compression of the assembly (as, for example, due to increased proximal fluid pressure due to a pump pressure stroke).
[0227] Responsiveness to cyclical longitudinal compression is in-part secondary, e.g., to compression of resilient peripheral seal 470 against a tunable valve seat 450 or 450 ′ (see, e.g., FIGS. 14A and 14B ). Responsiveness to cyclical longitudinal compression is also in-part secondary, e.g., to alteration of the shape of peripheral seal groove 418 (see FIG. 13 ). The shape of peripheral seal groove 418 is imposed on resilient peripheral seal 470 due to relative movement of proximal and distal groove walls 418 ′ and 418 ″ (see FIG. 13 ) during longitudinal compression of the assembly against a tunable valve seat 450 or 450 ′ (see, e.g., FIGS. 14A and 14B respectively). Note, as above herein, that the proximal and distal designations assume a suction valve (as opposed to a discharge valve) configuration.
[0228] Note also that the valve body 410 comprises peripheral valve seat interface 434 having a convex curvature (see section edge 436 in FIG. 14A ). Peripheral valve seat interface 434 undergoes a substantially elastic concave flexure with slight circular rotation as the valve body 410 seats against a tunable valve seat such as 450 or 450 ′ (see FIGS. 14A and 14B respectively), each tunable valve seat embodiment having a concave mating surface 454 with correspondingly less curvature (see, e.g., section edge 456 in FIG. 14A ) than the peripheral valve seat interface (see e.g., section edge 436 in FIG. 14A ). As a result, peripheral valve seat interface 434 achieves a circular rolling contact seal with concave mating surface 454 of either tunable valve seat 450 or tunable valve seat 450 ′. That is, the structures for achieving a circular rolling contact seal with peripheral valve seat interface 434 are identical in tunable valve seats 450 and 450 ′.
[0229] Further considering the first plurality of tunable vibration dampers in greater detail, a second damper (i.e., a central vibration damper) is schematically illustrated in valve body 410 (see FIG. 12 ). The second damper comprises surge chamber 460 and receiving area 464 in fluid communication with central circular tubular area 462 via longitudinally-opposing fluid flow restrictors 466 / 468 . In the presence of central fluid tuning medium 442 , central circular tubular area 462 and longitudinally-opposing fluid flow restrictors 466 / 468 are responsive to cyclical longitudinal compression of the assembly, resulting in cyclically reversible reductions of the internal volumes of central circular tubular area 462 and receiving area 464 . Such reversible volume reductions in central circular tubular area 462 and receiving area 464 prompt flow of central fluid tuning medium 442 through the longitudinally-opposing fluid flow restrictors 466 / 468 to surge chamber 460 in association with valve closure shock and/or vibration. Such flow of central fluid tuning medium 442 reverses with each cycle of longitudinal compression.
[0230] Thus, each of the radially-spaced (i.e., peripheral and central) vibration dampers of the first plurality of tunable vibration dampers comprises a circular tubular area (e.g., peripheral circular tubular area 472 / 474 and central circular tubular area 462 respectively), and at least one such vibration damper is tunable to a predetermined frequency (e.g., a resonant frequency of a fluid end in which the assembly is installed). The tuning mechanisms may differ: e.g., via central fluid tuning medium 442 in central circular tubular area 462 and/or via peripheral fluid tuning medium 482 / 484 (shown combined as an instantaneous shape of peripheral fluid tuning medium 480 ) within peripheral circular tubular area 472 / 474 . Note that central fluid tuning medium 442 is shown schematically being added in FIG. 12 via a sealable port 422 (see FIG. 13 ) through guide 412 in valve body 410 . Control of variable fluid flow resistance and/or fluid stiffness (e.g., in the case of fluid tuning media comprising one or more shear-thickening fluids) facilitates predetermination of resonant frequency or frequencies in the central and peripheral vibration dampers.
[0231] Note also that central fluid tuning medium 442 might also or alternatively be added via sealable port 420 in (distal) base plate 416 . And further note that proximal valve body portion 414 in FIG. 13 is separately identified to call attention to the possibility of fabricating base plate 416 and proximal valve body portion 414 separately and then welding them together to form valve body 410 . The terms proximal and distal in this paragraph assume a suction valve configuration; in a discharge valve configuration the positions of the terms would be reversed.
[0232] In either case, tuning is a function of responsiveness of the respective vibration dampers to vibration generated by valve closure impact (see above discussion of the vibration spectrum of an impulse). For example, longitudinal force on the closed (suction) valve will tend to reduce the distance between longitudinally-opposing fluid flow restrictors 466 / 468 , simultaneously prompting flow of central fluid tuning medium 442 from central circular tubular area 462 into receiving area 464 and, with sufficient longitudinal force, into surge chamber 460 . When central fluid tuning medium 442 comprises one or more shear-thickening materials, vibration damping will be a nonlinear function of (the longitudinal-force-dependent) fluid flow resistance associated with longitudinally-opposing fluid flow restrictors 466 / 468 .
[0233] Note that the viscosity of the central fluid tuning medium 442 may vary with time when shear-thickening material(s) are present in the central fluid tuning medium 442 , thereby introducing nonlinearity for predictably altering the center frequency and/or the Q of the central vibration damper. Analogous predetermined viscosity variation associated with changes of instantaneous shape of peripheral fluid tuning medium 480 is available for predictably altering the center frequency and/or the Q (i.e., altering the tuning) of the peripheral seal vibration damper 470 / 472 / 474 / 480 as the resilient peripheral seal 470 distorts under the cyclical longitudinal compressive load of valve closure.
[0234] Note also that the peripheral seal vibration damper 470 / 472 / 474 / 480 comprises a medial flange 479 sized to fit within flange channel 419 of valve body 410 . See detail breakout view A of FIG. 13 showing flange channel 419 and a peripheral valve seat interface 434 for sealing against concave mating surface 454 (see FIG. 14A ). See also detail breakout view B of FIG. 13 showing medial flange 479 of resilient peripheral seal 470 , medial flange 479 partially surrounding medial portion 474 of peripheral circular tubular area 472 / 474 within resilient peripheral seal 470 . Those skilled in the art know that conventional peripheral valve body seals (analogous-in-part to resilient peripheral seal 470 ) tend to rotate within their retaining groove as a conventional valve body mates with a conventional valve seat. Considered as a whole, the peripheral seal vibration damper illustrated herein that comprises peripheral seal vibration damper 470 / 472 / 474 / 480 shows that such rotation will be resisted by the combined action of medial flange 479 within flange channel 419 , together with rotation resistance inherent in the wedge-shape (seen in longitudinal cross-section as in FIG. 13 ) of peripheral circular tubular area 472 / 474 with its peripheral fluid tuning medium 480 .
[0235] Facilitating such combined action, the medial portion 474 of peripheral circular tubular area 472 / 474 (portion 474 being partially surrounded by flange channel 419 ) will tend to stiffen medial flange 479 in a nonlinear manner. The stiffening of medial flange 479 is due in part to the presence of shear-thickening material in peripheral fluid tuning medium 480 (and particularly the medial fluid tuning medium portion 484 thereof) in peripheral circular tubular area 472 / 474 . Thus, a schematically illustrated example (see FIG. 13 ) of peripheral circular tubular area 472 / 474 is shown as containing peripheral fluid tuning medium 480 (peripheral fluid tuning medium portions 482 / 484 being shown as having the instantaneous shape schematically illustrated in FIGS. 13 and 14B ).
[0236] Combined action resisting rotation of peripheral seal vibration damper 470 / 472 / 474 / 480 is also facilitated by the wedge-shape (as shown schematically in longitudinal cross-section in FIG. 13 ) of the instantaneous representation of peripheral fluid tuning medium 480 within peripheral circular tubular area 472 / 474 . The wedge-shape has a relatively thicker portion adjacent to lateral boundary 481 and a relatively thinner portion adjacent to medial boundary 483 . As shown in FIG. 13 , the wedge-shape of the instantaneous representation of peripheral fluid tuning medium 480 tapers monotonically in thickness from the relatively thicker portion adjacent to lateral boundary 481 to the relatively thinner portion adjacent to medial boundary 483 .
[0237] Rotation of a peripheral seal vibration damper 470 / 472 / 474 / 480 as a whole would then necessarily require rotation of the instantaneous shape of peripheral fluid tuning medium 480 , with the thicker lateral portion translating proximally and medially (relative to more central portions of the valve body and seal assembly) during closure of a suction valve and compression of resilient peripheral seal 470 . Relative proximal translation of the more peripheral portion of resilient peripheral seal 470 occurs during valve closure for two reasons. The first reason (1) is: because the seal strikes the tunable valve seat first, causing the more peripheral seal portion to be distorted by the tunable valve seat contact, the peripheral seal portion being relatively free to move in relation to more central portions of the valve body and seal assembly due to the resilient character of the seal itself. The second reason (2) is: because of the elastic valve body concave flexure, with slight circular rotation, that accompanies valve closure (as described herein).
[0238] Note that slight circular rotation includes slight translation proximally and medially of the thicker lateral portion of the peripheral fluid tuning medium 480 . And medially directed force exerted on the peripheral seal by the tunable valve seat adds to the tendency of the thicker portion of the wedge-shaped peripheral fluid tuning medium 480 to rotate medially. But this medial movement would require compression of the relatively thicker lateral portion of instantaneous shape of peripheral fluid tuning medium 480 . Such thicker-portion compression of the peripheral fluid tuning medium 480 would be resisted nonlinearly, and relatively strongly, with consequent energy dissipation as heat in the shear-thickening material(s) within the fluid tuning medium. Thus, rotation resistance in peripheral seal vibration damper 470 / 472 / 474 / 480 as a whole contributes to dissipation of closing impulse energy. And such energy dissipation, in turn, contributes to vibration damping.
[0239] Further vibration damping in the illustrated alternate tunable check valve embodiment takes place in the second plurality of tunable vibration dampers. To support description of the damping in greater detail, alternate tunable check valve assembly embodiment 442 / 410 / 470 / 480 is shown in FIG. 14B combined with tunable valve seat lateral support assembly 450 ′/ 724 / 722 / 720 / 718 / 716 / 714 / 712 / 710 . The combination is analogous-in-part to that schematically illustrated in FIG. 11 . Formation of a circular rolling contact seal between the tunable valve seat's concave mating surface 454 and the correspondingly greater curvature of peripheral valve seat interface 434 is described above. The lateral support assembly comprises first and second adjustable end spacers ( 710 and 724 respectively) in combination with a plurality of tunable circular viscoelastic support elements ( 714 , 718 and 722 ). Each support element comprises a support circular tubular area ( 712 , 716 and 720 respectively). At least one such tubular area being substantially filled with at least one shear-thickening material analogous to material 80 (see, e.g., FIG. 5 ). Each shear-thickening material is chosen to achieve at least one predetermined assembly resonant damping frequency.
[0240] FIGS. 15 and 16A illustrate partial schematic 3-dimensional views of a tunable hydraulic stimulator embodiment 599 , FIG. 16A being an exploded view of stimulator embodiment 599 . FIG. 16B , in contrast, is an exploded view of a stimulator embodiment 699 , which is similar to embodiment 599 in some respects but different in its inclusion of several structures (e.g., a peripheral transverse coil 682 within coil form 680 and powered by cable 684 ). An additional difference between stimulators 599 and 699 is the multi-layer form of fluid interface 621 / 622 / 623 in stimulator 699 , compared to the single-layer form of fluid interface 520 in stimulator 599 .
[0241] In stimulator 599 , a hollow cylindrical housing 590 has a longitudinal axis, a first end 594 , and a second end 592 . First end 594 is closed by fluid interface 520 for transmitting and receiving vibration. Fluid interface 520 comprises at least one accelerometer 518 for producing an accelerometer electrical signal (i.e., an accelerometer-generated feedback signal) representing vibration transmitted and received via fluid interface 520 . In stimulator 699 , a hollow cylindrical housing 690 has a longitudinal axis, a first end 694 , and a second end 692 . Second end 692 is closed by fluid interface 621 / 622 / 623 for transmitting and receiving vibration. Fluid interface 621 / 622 / 623 comprises at least one accelerometer (e.g., a MEMS accelerometer represented by its cable connection 601 , 602 and/or 603 ) for producing at least one accelerometer electrical signal (i.e., an accelerometer-generated feedback signal) representing vibration transmitted and received via fluid interface 621 / 622 / 623 . Advantages of the more complex structure of stimulator 699 , compared to stimulator 599 , are explained in the following discussion.
[0242] Referring to stimulator 599 ( FIGS. 15 and 16A ), driver element 560 (comprising a field emission structure which itself comprises electromagnet/controller 564 / 562 ) reversibly seals second end 592 , and hammer (or movable mass) element 540 is longitudinally movable within housing 590 between driver element 560 and fluid interface 520 . In some embodiments, hammer element 540 may itself be a field emission structure consisting of a permanent magnet (or consisting of a plurality of permanent magnets). Polarity of any such permanent magnets is not specified because it would be assigned in light of the electromagnet/controller 564 / 562 . Alternatively, hammer element 540 may be analogous in part to the armature of a linear electric motor, as in a railgun. (See, e.g., the '205 and '877 patents noted above). Note that the above accelerometer-generated feedback electrical signal may be augmented by, or replaced by, sensorless control means (e.g., controlling operating parameters of electromagnet 564 such as magnetic field strength and polarity) in free piston embodiments of the tunable hydraulic stimulator. (See, e.g., U.S. Pat. No. 6,883,333 B2, incorporated by reference). The above description applies analogously to stimulator 699 , comprising driver element 660 and hammer 640 interacting with fluid interface 621 / 622 / 623 within housing 690 .
[0243] Thus, in stimulator 599 , hammer element 540 is responsive to the magnetic field emitted by driver element 560 for striking, and rebounding from, fluid interface 520 . In stimulator 699 , hammer element 640 is responsive to the magnetic field emitted by driver element 660 for striking, and rebounding from, fluid interface 621 / 622 / 623 . The duration of each such striking and rebounding cycle (termed herein the “rebound cycle time”) has the dimension of seconds. And the inverse of this duration has the dimension of frequency. Hence, the term herein “characteristic rebound frequency” is the inverse of a rebound cycle time, and the rebound cycle time itself is inversely proportional to the bandwidth of transmitted vibration spectra resulting from each hammer strike and rebound from fluid interface 520 or fluid interface 621 / 622 / 623 .
[0244] Fluid interface 520 or fluid interface 621 / 622 / 623 transmits vibration spectra generated by hammer impacts on the respective fluid interface, as well as receiving backscatter vibration from geologic formations excited by the transmitted vibration. Either fluid interface configuration comprises, for example, one or more MEMS accelerometers for producing an accelerometer signal representing vibration transmitted and received by the fluid interface. (See MicroElectro-Mechanical Systems in Harris, pp. 10-26, 10-27).
[0245] Hammer element 540 comprises a striking face 542 (see FIG. 16A ) which has a predetermined modulus of elasticity (e.g., that of mild steel, about 29,000,000 psi) which can interact with the modulus of elasticity of fluid interface 520 (again, e.g., that of mild steel). In an illustrative example, interaction of the two suggested moduli of elasticity predetermines a relatively short rebound cycle time for hammer element 540 , which is associated with a corresponding relatively broad-spectrum of vibration to be transmitted by fluid interface 520 . In other words, striking face 542 strikes fluid interface 520 and rebounds to produce a relatively short-duration, high-amplitude mechanical shock. (See, e.g., Harris p. 10.31).
[0246] In contrast, fluid interfaces of stimulators of class 699 (see FIG. 16B ) each comprise one or more disc-shaped thin members which are analogous-in-part to disc-shaped thin member 621 , disc-shaped thin member 622 and/or disc-shaped thin member 623 . The illustrated fluid interface embodiment 621 / 622 / 623 comprises the three illustrated disc-shaped thin members in a compact (e.g., laminated) subassembly for purposes of description only, but alternate fluid interface embodiments of the invention may contain more or fewer disc-shaped thin members. At least one disc-shaped thin member within fluid interface 621 / 622 / 623 comprises ferromagnetic amorphous alloy, the effective elastic modulus of which is magnetostrictively-responsive to a step-wise adjustable steady-state longitudinal magnetic field created by electrical current in peripheral transverse coil 682 which is schematically shown as enclosed in coil form 680 . The longitudinal magnetic field influences the effective hardness of, and thus the resonant frequencies of: (1) at least one disc-shaped thin member 621 , 622 and/or 623 and (2) the fluid interface 621 / 622 / 623 as a whole. Further, at least one disc-shaped thin member within fluid interface 621 / 622 / 623 comprises a vibration detector for generating a vibration electrical signals representing both vibration transmitted and characteristic backscatter vibration received via fluid interface 621 / 622 / 623 .
[0247] Note that neither vibration transmitted nor backscatter vibration received (as claimed in the present invention) are corrupted by electromagnetically-induced vibration of the fluid interface 621 / 622 / 623 . While electromagnetically-induced vibration of the fluid interface may occur during changes in the longitudinal magnetic field (e.g., during changes in an adjustable, alternating or time-varying magnetic field), such corruption of either vibration transmitted or characteristic backscatter vibration received is prevented in the present invention by limiting transmitted and received vibration measurements to periods when the step-wise adjustable longitudinal magnetic field is unchanging (i.e., when the field is in a steady-state).
[0248] Both FIGS. 15 and 16A schematically illustrate a tunable resilient circumferential seal 580 for sealing housing 590 within a wellbore, thus partially isolating vibration transmitted by fluid interface 520 within the wellbore. Seal 580 comprises at least one circular tubular area 582 which may contain at least one shear-thickening fluid 80 (see FIG. 5 ) which is useful in part for tuning purposes. And fluid 80 may comprise nanoparticles 82 for, e.g., facilitating heat scavenging.
[0249] FIG. 16A also schematically illustrates a first electrical cable 516 for carrying accelerometer feedback electrical signals (schematically representing vibration data transmitted by and/or received by fluid interface 520 ) from accelerometer 518 to driver element 560 . A second electrical cable 514 also connects to driver element 560 of each tunable hydraulic stimulator to schematically represent interconnection of two or more such stimulators (to form a tunable hydraulic stimulator array) and/or for connecting one or more down-hole tunable hydraulic stimulators to related equipment (e.g., programmable controller 650 as shown in FIGS. 17 and 18 ) proximal in a wellbore and/or adjacent to the wellhead. Accelerometer electrical signals provide feedback on transmitted vibration and also on received backscatter vibration to driver element 560 . Analogous cabling 696 is illustrated in FIG. 16B for connecting programmable controller 650 with accelerometer(s) 601 , 602 and/or 603 , with driver element 660 , including driver electronics 662 (via cable 614 ), and with peripheral transverse coil 682 (via cable 684 ).
[0250] While accelerometer-mediated feedback may be desired for tailoring stimulation to specific geologic formations and/or to progress in producing desired degrees for fracture within a geologic formation, predetermined stimulation protocols may be used instead to simplify operations and/or lower costs.
[0251] In certain embodiments, frac diagnostic software and data to implement sensorless control via operating parameters (e.g., magnetic field strength and polarity) of electromagnet 564 , or to implement feedback control incorporating accelerometer 518 , are conveniently stored and executed in a microprocessor (located, e.g., in controller 562 ). (See, e.g., U.S. Pat. No. 8,386,040 B2, incorporated by reference). See FIGS. 5 and 6 of the '040 patent reference, for example, with their accompanying specification.
[0252] Note, however, that while certain of the electrodynamic control characteristics of a tunable hydraulic stimulator may be represented in earlier devices, the tunable hydraulic stimulator's reliance on mechanical shock (e.g., generated by hammer strike and rebound) to generate tuned vibration (i.e., vibration characterized by approximately predetermined magnitude and/or frequency and/or PSD) imposes unique requirements indicated by the dynamic responsiveness of certain mechanical structures (e.g., hammers and fluid interfaces) to electromagnetic effects of field-emitting components (e.g., electromagnets and electret materials) as described herein. Variability of stimulation vibration is further responsive to one or more programmable controllers via, e.g., the power/data cable 514 , and/or an analogous communication medium or control link (see FIGS. 16A and 17 ). Such responsiveness may extend to other hydraulic stimulators and/or to wellhead or other auxiliary equipment (see, e.g., FIG. 17 ) that may 1) power the hydraulic stimulator, 2) receive and transmit stimulation-related data, 3) coordinate stimulator operation (e.g. vibration phase, frequency, amplitude and/or PSD) with related equipment, and/or 4) modify driver-related frac diagnostic software programs affecting tunable hydraulic stimulator operations.
[0253] Note also that in addition to individual applications of a tunable hydraulic stimulator, two or more such stimulators may operate in a combined tunable hydraulic stimulator array during a given stage of fracking (e.g., in a temporarily isolated section or stage of horizontal wellbore). Section isolation in a wellbore may be accomplished with swell packers, which may function interchangeably in part as the tunable resilient circumferential seals described herein. A single tunable hydraulic stimulator or an interconnected tunable hydraulic stimulator array may be programmed in near-real time to alter stimulation parameters in response to changing conditions in geologic materials adjacent to a wellbore. A record of such changes, together with results, guides future changes to increase stimulation efficiency.
[0254] In summary, the responsiveness of certain elements of a tunable hydraulic stimulator to other elements and/or to parameter relationships facilitates operational advantages in various alternative stimulator embodiments. Examples involving such responsiveness and/or parameter relationships include, but are not limited to: 1) driver element 560 comprises a field emission structure comprising an electromagnet/electronics 564 / 562 having cyclical magnetic polarity reversal characterized by a variable polarity reversal frequency; 2) longitudinal movement of hammer (or movable mass) element 540 is responsive to the driver cyclical magnetic polarity reversal; 3) longitudinal movement of hammer element 540 striking, and rebounding from, fluid interface 520 may be substantially in-phase with the polarity reversal frequency to generate vibration transmitted by fluid interface 520 ; 4) the driver element polarity reversal frequency may be responsive to accelerometer 518 's electrical signal (and thus responsive to vibration sensed by accelerometer 518 ; 5) longitudinal movement of hammer element 540 may be substantially in-phase with the polarity reversal frequency; 6) longitudinal movement of hammer element 540 striking, and rebounding from, fluid interface 520 has a characteristic rebound frequency which, as noted above, is the inverse of the rebound cycle time; 7) the hammer may rebound in-phase with polarity reversal and; 8) the rebound cycle time is a function of i) the cyclical magnetic polarity of driver element 560 and/or; ii) the moduli of elasticity of hammer element 540 and fluid interface 520 .
[0255] FIG. 17 schematically illustrates a 2-dimensional view of major components and interconnections of a tunable down-hole stimulation system 698 ′, together with brief explanatory labels and comments on component functions. As aids to orientation, a schematic wellbore is shown, including surface pipe connections with pumps. Hydraulic pathways are illustrated for transmitting broad-spectrum vibration to, and receiving band-limited backscatter vibration from, down-hole geologic material adjacent to the wellbore. The hydraulic pathways are shown passing to and from geologic material via, e.g., a preformed casing slot or an explosively-formed casing perforation.
[0256] The tunable down-hole stimulation system 698 ′ schematically illustrated in FIG. 17 is relatively sophisticated, employing several structures, functions and interactions that may appear in different invention embodiments (but that need not appear in all invention embodiments) and are described in greater detail below. To improve clarity, certain structures and functions inherent in the system of FIG. 17 are schematically represented in FIGS. 15-16 . For example, references to specific elements (e.g., hammer element 540 or fluid interface 520 ) should be understood with reference to FIGS. 15-16 . Further, the illustration of tunable down-hole stimulator 648 in FIG. 17 should be understood as including a tunable hydraulic vibration generator (labeled as such) which is analogous to the illustrated tunable hydraulic stimulator 599 in FIGS. 15-16 . So while a portion of tunable down-hole stimulator 648 should be understood as schematically analogous to tunable hydraulic stimulator 599 , it should also be recognized that stimulator 648 represents a different (expanded in part) subset of structures and functions not represented in stimulator 599 .
[0257] A first example of a tunable down-hole stimulation system is one of the embodiments schematically illustrated in portions of FIGS. 15-17 . The embodiment comprises at least one frac pump 688 for creating down-hole hydraulic pressure, together with at least one tunable down-hole stimulator 648 . Each stimulator 648 comprises a tunable hydraulic vibration generator (labeled in FIG. 17 ) for transmitting vibration hydraulically, as well as a programmable controller 650 for creating a plurality of control signals and transmitting at least one control signal to each said frac pump 688 and each said tunable down-hole stimulator 648 . Additionally, each tunable down-hole stimulator 648 comprises at least one accelerometer 518 for sensing vibration and for transmitting an electrical signal derived therefrom. And the programmable controller 650 is responsive to accelerometer 518 via the electrical signal derived therefrom.
[0258] A second example of a tunable down-hole stimulation system is one of the embodiments schematically illustrated in portions of FIGS. 15-17 . The embodiment comprises at least one frac pump 688 for creating down-hole hydraulic pressure, together with at least one proppant pump 618 connected in parallel with at least one frac pump 688 for adding exogenous proppant. The system further comprises at least one tunable down-hole stimulator 648 , each stimulator 648 comprising a tunable hydraulic vibration generator (labeled in FIG. 17 ) having a characteristic rebound frequency. A programmable controller 650 is included for creating a plurality of control signals and transmitting at least one control signal to each frac pump 688 , each proppant pump 618 , and each tunable down-hole stimulator 648 . Each tunable down-hole stimulator 648 comprises at least one accelerometer 518 for detecting vibration and for transmitting an electrical signal derived therefrom, and each accelerometer 518 is responsive to the characteristic rebound frequency. Finally, the programmable controller 650 is responsive to accelerometer 518 via the electrical signal.
[0259] A third example of a tunable down-hole stimulation system is one of the embodiments schematically illustrated in portions of FIGS. 15-17 . The embodiment comprises a wellbore comprising a vertical wellbore, a kickoff point, a heel, and a toe (all portions labeled in FIG. 17 ). At least one frac pump 688 creates down-hole hydraulic pressure in the wellbore, and at least one tunable down-hole stimulator 648 is located within the wellbore (and between the heel and toe as labeled in FIG. 17 ). Each stimulator comprises a tunable hydraulic vibration generator (labeled in FIG. 17 ), and a programmable controller 650 creates a plurality of control signals and transmits at least one control signal to each frac pump 688 and each tunable down-hole stimulator 648 . Each tunable down-hole stimulator 648 comprises at least one accelerometer 518 for sensing vibration and for transmitting an electrical signal derived therefrom, and the programmable controller 650 is responsive to accelerometer 518 via the electrical signal.
[0260] An alternative embodiment included in the tunable down-hole stimulation system 698 ′ of FIG. 17 , for example, comprises at least one frac pump 688 for creating down-hole hydraulic pressure. System 698 ′ further comprises at least one down-hole tunable hydraulic stimulator 648 for generation and transmission of broad-spectrum vibration, and for detection of backscatter vibration, stimulator 648 being hydraulically pressurized by frac pump 688 . A programmable controller 650 is linked to at least one frac pump 688 and at least one tunable hydraulic stimulator 648 for controlling down-hole hydraulic pressure and vibration generation as functions of backscatter vibration sensed by one or more detectors on at least one tunable hydraulic stimulator 648 . Each tunable hydraulic stimulator 648 comprises a movable mass or hammer element 540 (see FIGS. 15-16 ) which is movable via a field emission structure in the form of an electromagnet/controller 562 / 564 to strike, and rebound from, a fluid interface 520 (see FIGS. 15-16 ) for generating broad-spectrum vibration (see FIG. 17 ). At least one tunable hydraulic stimulator 648 detects the backscatter vibration via an accelerometer 518 coupled to fluid interface 520 (see FIGS. 15-16 ). An electric signal derived from accelerometer 518 is carried via link 516 , link 514 and at least one additional link 654 (labeled in FIG. 17 ) to programmable controller 650 . The broad-spectrum vibration indicated in FIG. 17 is characterized by a vibration spectrum having a predetermined PSD, and programmable controller 650 (see FIG. 17 ) alters the predetermined PSD during the course of stimulation as a function of the backscatter vibration.
[0261] The alternative embodiment of the tunable stimulation system 698 ′ described above may be further described as follows: tunable down-hole hydraulic stimulator 648 comprises a hollow cylindrical housing 590 having a longitudinal axis, a first end 594 , and a second end 592 , first end 594 being closed by fluid interface 520 for transmitting and receiving vibration, and fluid interface 520 comprising at least one accelerometer 518 for producing an accelerometer signal representing vibration transmitted and received by fluid interface 520 . A driver element 560 reversibly seals second end 592 , and driver element 560 comprises a field emission structure comprising an electromagnet/controller 562 / 564 having cyclical magnetic polarity reversal characterized by a variable polarity reversal frequency.
[0262] The alternative embodiment of the tunable stimulation system 698 ′ may additionally comprise at least one temperature sensor (labeled in FIG. 17 ). Down-hole hydraulic pressure may be sensed (as labeled in FIG. 17 ) and transmitted as a pressure signal derived therefrom. Programmable controller 650 (through change in one or more of the control signals it produces) is responsive to the pressure signal when present. Pressure may analogously be controlled as a function-in-part of both temperature and backscatter vibration sensed at tunable down-hole stimulator 648 . And predetermined PSD may similarly be altered as a function-in-part of both temperature and backscatter vibration sensed at tunable down-hole stimulator 648 .
[0263] In the above embodiments, a field emission structure may be responsive to at least one control signal (e.g., timed stimulator transmission signals and/or timed stimulator shift signals). Such responsiveness to at least one control signal is achieved, e.g., by emitting one or more electric and/or magnetic fields which are functions of at least one control signal as sensed by the field emission structure through change in one or more field emission structure electrical parameters. Thus, vibration transmitted by a down-hole hydraulic vibration generator may have a predetermined PSD which is a function of its rebound cycle time. The rebound cycle time, in turn, being dependent-in-part on one or more field emission structures that are themselves responsive to at least one control signal (e.g., a stimulator shift signal). A timed stimulator shift signal, in turn, may be responsive to one accelerometer feedback signal (e.g., via cable 516 in FIG. 16 ).
[0264] FIG. 18 schematically illustrates an embodiment 698 of an adaptive stimulation system which differs from embodiment 698 ′ of a tunable down-hole stimulation system in FIG. 17 . A portion of the 2-dimensional stimulation system view of FIG. 17 is reproduced in FIG. 18 , but differences between FIGS. 17 and 18 include replacement of a single tunable down-hole stimulator (in FIG. 17 ) with linear array 648 comprising three analogous tunable down-hole stimulators ( 638 ′, 638 ″ and 638 ′) in FIG. 18 . Descriptions of functional features of stimulators in FIG. 18 resemble (in-part) analogous descriptions of the stimulator in FIG. 17 , but adaptive stimulation system 698 combines impulse-generated swept-frequency stimulation vibration with cyclically-varying hydraulic pressure to provide adaptive down-hole stimulation. Swept-frequency stimulation vibration arises from cyclical up-shifts and down-shifts of the PSD of impulse-generated stimulation vibration. The cyclical PSD shifts, in turn, are achieved via closed-loop control of the impulse-generated vibration produced by linear array 648 . PSD's may be adjusted for resonance excitation, fracturing and/or analysis of geologic materials at varying distances from a wellbore when combined with cyclically-varying down-hole hydraulic pressure.
[0265] Thus, a distinct functional feature of adaptive stimulation system 698 is creation of cyclically-varying down-hole hydraulic pressure by frac pump 688 in response to a timed pressure signal from programmable controller 650 . Further, descriptions of structural features of stimulators in FIGS. 17 and 18 resemble (in-part) analogous descriptions associated with FIGS. 15 and 16 . Thus, detailed labeling and/or annotating of stimulators in FIG. 18 are minimized to improve readability.
[0266] Stimulation linear array 648 may behave in-part in a manner analogous to that of a phased array antenna. For example, elective discrete time delays among sequential transmission times for vibration bursts from each stimulator in array 648 are controlled via timed stimulator transmission signals from programmable controller 650 so as to exert control over the propagation direction of the combined stimulation vibration (i.e., control over the directionally propagated array vibration wave front). Timed stimulator transmission signals, in turn, may have a phase relation (e.g., in-phase) with timed pressure signals sent to frac pump 688 .
[0267] And other timing issues affect vibration from each hydraulic stimulator in linear array 648 . For example, differences in individual rebound cycle times among the stimulators affect their individual PSD's. Adjustable rebound cycle times, in turn, may reflect changes in electrical parameters (e.g., magnetic field polarity, magnetic field strength, and/or the phase relationship of stimulator driver polarity reversal to hammer strike). Variability in adjustable rebound cycle times (e.g., non-uniform rebound cycle times) may also be responsive to timed stimulator shift signals from programmable controller 650 . Such variability may result in vibration interference among stimulators in a spatial array. Both constructive interference (i.e., increase in amplitude) at one or more frequencies and destructive interference (i.e., decrease in amplitude) at other frequencies are likely, providing higher stimulation vibration energy levels at a plurality of discrete frequencies within a vibration burst.
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Adaptive stimulation systems combine impulse-generated swept-frequency stimulation vibration with cyclically-varying hydraulic pressure to provide adaptive down-hole stimulation. Swept-frequency stimulation vibration arises from cyclical shifts of the power spectral density (PSD) of each stimulator's fluid interface vibration (via closed-loop control of the rebound cycle time and/or the fluid interface's effective elastic modulus). PSD's are adjusted for resonance excitation and fracturing of geologic materials at varying distances from a wellbore, closed-loop control incorporating backscatter vibration from stimulated geologic material. One or more stimulators generate vibration in bursts comprising a plurality of vibration frequencies. Timed signals from a programmable controller affect directional propagation of combined vibration wave fronts from a stimulator array. As fracturing proceeds to smaller (e.g., proppant-sized) fragments having higher resonant frequencies, PSD's are up-shifted, increasing relative stimulation vibration power in higher frequencies. Progressive stimulation is thereby optimized, facilitating plain-water (or liquefied propane) fracs with self-generated proppant.
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BACKGROUND OF THE INVENTION
The invention relates to a blown film comprising a polypropylene composition. In particular, the invention relates to polypropylene blown films having excellent optical properties, as well as mechanical properties.
Polypropylene for films is today almost exclusively used for cast films. In the cast film process a very quick cooling of the melt is achieved with a chill roll, in order to utilise the potentially good optical and mechanical properties of polypropylene for film applications.
Until now, polypropylene could be used in the blown film process only when it was possible to use water contact cooling in order to achieve the same quick cooling as in the cast film process.
In a conventional blown film process using air cooling, the polypropylene melt and the films produced from it are only slowly cooled. This results in insufficient optical and mechanical parameters because the slow cooling process causes an uncontrolled growth of the crystal- and spherolitic structure. Polypropylene blown films produced with air cooling are both cloudy and brittle.
It has been tried to improve the problem of cloudiness and brittleness of polypropylene blown films by using a combination of propylene random copolymer with either inorganic nucleating agent or sorbitol-based nucleating agents. Improvements of optical and mechanical parameters were only possible to a very limited extent.
It is therefore the object of the invention to provide a polypropylene blown film having good optical parameters, comparable to those obtained with a cast film, together with a well balanced stiffness/drawability ratio.
SUMMARY OF THE INVENTION
The above object is achieved by a blown film comprising a polypropylene composition containing a propylene homopolymer or propylene copolymer with ethylene and/or another α-olefin, the polypropylene composition containing a clarifier comprising one or more phosphate-based α-nucleating agents and/or polymeric α-nucleating agents selected from the group consisting of vinylcycloalkane polymers and vinylalkane polymers.
It was surprisingly possible to produce a polypropylene blown film having excellent optical parameters, good stiffness (tensile modulus) and drawability (elongation at break) on a conventional blown film plant using air cooling.
This is particularly surprising, because for most other applications including blow molding, injection molding and also cast film, the sorbitol-based nucleating agents give the best or comparable gloss and haze.
The propylene copolymer can be heterophasic or random, the latter being preferred. It contains ethylene and/or another a olefin, the a olefin can be a C 4 -C 10 , preferably a C 4 - C 6 α olefin.
The ethylene content of the copolymer can be up to 10 wt % or up to 8 wt %. A preferred content is less than 5 wt %, for example from 0,3 wt % to 4,8 wt %.
Additionally the composition can contain other polymers like HDPE, LDPE, LLDPE, VLDPE, ULDPE or other polymers or copolymers containing ethylene and another α-olefin.
The α-nucleating agents which may be used for the blown films of the invention include aluminum-hydroxy-bis[2,2′-methylene-bis(4,6-di-t-butylphenyl) phosphate] and/or polymeric α-nucleating agents selected from the group consisting of vinylcycloalkane polymers and vinylalkane polymers. Nucleation with these polymeric nucleating agents is either accomplished by a special reactor technique, where the catalyst is prepolymerised with monomers like e.g. vinylcyclohexane (VCH), or by blending the propylene polymer with the vinyl(cyclo)alkane polymer. These methods are described in greater detail in e.g. EP 0 316 187 A2 and WO 99/24479.
Among all α-nucleating agents mentioned above aluminum-hydroxy-bis[2,2′-methylene-bis (4,6-di-t-butylphenyl)phosphate] is preferred.
It was found, that the intended effects, i.e. increased gloss, reduced haze and improved stiffness, are especially pronounced when this type of α-nucleating agent is used.
Smaller amounts of α-nucleating agents than 0,001 wt % usually do not give the desired level of effect, while with larger amounts than 5 wt %, although giving the desired effect, the produced blown films are becoming too expensive because of the high priced nucleating agents.
A further aspect of the invention relates to multilayer blown films, where at least one layer is comprised of a polypropylene blown film according to the invention.
When polypropylenes are used, which are nucleated with sorbitol-based nucleating agents, it is not possible to coextrude such multilayer blown films without problems, because the volatility of sorbitol-based nucleating agents is already very high in the range of the necessary processing temperatures of the further layer(s). This causes rapidly growing deposits of nucleating agent around the extrusion die. The deposits have to be periodically removed for which it is necessary to stop the entire production.
Therefore, the further aspect of the invention relates to multilayer blown films, where at least one layer is comprised of a polypropylene blown film containing a clarifier comprised of one or more phosphate based α-nucleating agents and at least one further layer is comprised of a polymer having a higher melting temperature than the polypropylene.
In addition to the benefits gained from the improved optical and mechanical properties of the polypropylene layer, such multilayer blown films can be produced by coextrusion without causing deposits around the extrusion die.
The polymers having a higher melting temperature than the polypropylene which are used for the coextrusion of multilayer blown films are preferably any one or more of polyamide, polyvinylalcohol and polyethylene terephthalate.
According to a further embodiment of the invention a multilayer blown film comprises at least two layers, wherein at least one layer comprises a polypropylene composition according to the invention and at least one further layer is comprised of an ethylene polymer.
In areas, where very low seal initiation temperature (SIT) in combination with good optics is required, it has been found, that combinations of polypropylenes with polyethylenes (e.g. C 4 -LLDPE or LDPE) are beneficial. Compared to PE, PP has high temperature resistance while PE has low SIT. For fast sealing process on packaging lines it is necessary to have as high sealing temperature as possible. Consequently, this requires a film with a top layer (the layer, which has direct contact to the sealing bars) having a high melt temperature in order to withstand the high sealing temperatures and a sealing layer with a very low melting temperature which starts sealing at lowest possible temperature and providing good seam strength. Such film properties can be achieved by a combination of transparent PP for the top layer and PE for the sealing layer.
According to a further aspect the multilayer blown film comprises an adhesive layer intermediate to and adjacent to both the layer comprising a polypropylene composition according to the invention and the further layer comprising an ethylene polymer.
In the case of conventional PE, an adhesive layer is required between those layers in order to give sufficient bonding strength between the PP and PE layer since PP and conventional PE have different polarities and therefore not sufficient adhesion.
According to a still further embodiment the layer comprising a polypropylene composition according to the invention and the further layer comprising an ethylene polymer are adjacent to each other and the further layer is selected for having good adhesion to the layer comprising the polypropylene composition.
The presence of an adhesive layer requires that such films can be produced by using at least a 3 layer coex film. It is therefore advantageous, when an intermediate adhesive layer can be omitted and the further layer itself is selected to provide sufficient bonding strength to the PP-layer.
According to an advantageous embodiment, the ethylene polymer of the further layer is a single site catalyst polyethylene (SSC-PE).
By using a single site catalyst PE (SSC-PE) which is characterised by a low density (below 0,920 g/cm3) instead of the standard PE, a good adhesion to PP is obtained and no extra adhesive layer inbetween the PP- and PE-layer is necessary.
The polypropylene compositions which are used for the films of the invention may contain various additives, which are generally used in polypropylene compositions, such as stabilisers, antioxidants, acid neutralising agents, lubricants, ultraviolet absorbers, antiblocking agents, antistatic agents, antifogging agents, etc.
Preferred antioxidants are phenolic antioxidants, e.g. 2-t-butyl4,6-dimethylphenol, 2,6-di-t-butyl-4-methyl-phenol, 2,6-di-t-butyl-4-isoamylphenol, 2,6-di-t-butyl-4-ethylphenol, 2-t-butyl-4,6-diisopro-pylphenol, 2,6-dicyclopentyl-4-methylphenol, 2,6-di-t-butyl-4-methoxymethyrphenol, 2-t-butyl-4,6-dioctadecylphenol, 2,5-di-t-butylhydroquinone, 2,6-di-t-butyl-4,4-hexadecyloxyphenol, 2,2′-methylene-bis(6-t-butyl-4-methylphenol), 4,4′-thio-bis-(6-t-butyl-2-methylphenol), octade-cyl 3(3,5-di-t-butyl-4-hydroxyphenyl) propionate, 1,3,5-trimethyl-2,4,6-tris(3′,5′-di-t-bu-tyl-4-hydroxybenzyl)benzene and pentaerythrityl-tetrakis-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate.
Preferred stabilisers are phosphite based stabilisers, e.g. tris-(2,4-di-tert.butylphenyl)-phosphite.
The acid neutralising agents and/or lubricants are preferably carboxylic acid salts, where the metal is selected from the 1st or 2nd group of the periodic table or from transition metals like Zinc. Also synthetic hydrotalcite or Magnesium oxide can be used. Preferred carboxylates are Li-Stearate, Na-Stearate, K-Stearate, Li-Myristate, Na-Myristate, K-Myristate, Ca-Stearate, Mg-Stearate, Ca-12-hydroxy stearate, Mg-12-hydroxy stearate, Ca-Myristate, Ca-Palmitate, Ca-Laurate, Mg-Myristate, Mg-Palmitate, Mg-Laurate and Zn-Stearate.
DETAILED DESCRIPTION OF THE INVENTION
Description Of Measurement Methods
MFR
The melt flow rates were measured with a load of 2.16 kg at 230° C. The melt flow rate is that quantity of polymer in grams which the test apparatus standardised to ISO 1133 extrudes within 10 minutes at a temperature of 230° C. under a load of 2.16 kg.
Comonomer Contents
Comonomer contents (ethylene) were measured with Fourier transform infrared spectroscopy (FTIR) calibrated with 13 C-NMR.
Gloss
Gloss was determined according to DIN 67530 on cast films (thickness 50 μm) and on blown films (thickness 40 μm) at an angle of 20°.
Haze
Haze was determined according to ASTM D 1003-92 on injection moulded test plaques (60×60 ×2 mm), on cast films (thickness 50 μm) and on blown films (thickness 40 μm).
Tensile Test
Tensile test was performed according to ISO 527-3 on cast films (thickness 50 μm) and on blown films (thickness 40 μm).
Elmendorf
Elmendorf was determined according to ISO 6383/2 (1983) on cast films (thickness 50 μm) and on blown films (thickness 40 μm).
EXAMPLES
The following polymers were used for the examples and comparative examples.
TABLE 1
nucleating
nucleating agent
Haze
MFR
C2
agent
concentration
(injection moulded)
polymer
polymer type
[g/10 min]
[wt %]
type
[wt %]
[%]
polymer 1
random copolymer
1.5
4.8
NA21
0.2
23.0
polymer 2
random copolymer
1.5
4.8
Millad 3988
0.2
21.3
polymer 3
homopolymer
2
—
no
—
87.3
polymer 4
homopolymer
8
—
no
—
Millad 3988 . . . 1,3:2,4 bis(3,4-dimethyl-benzylidene) sorbitol
NA21 . . . commercially available from Asahi Denka Kogyo (Japan) under the name “ADK STAB NA21E”. NA21 contains aluminium-hydroxy-bis[2,2′-methylene-bis(4,6-di-t-butylphenyl)phosphate].
Polymers 1 to 4 are equipped with conventional stabilisation, i.e. 0.15 wt % Tris-(2,4-di-tert.butylphenyl)-phosphite, 0.1 wt % Pentaerythrityl-tetrakis-[3-(3,5-di-tert.butyl-4-hydroxyphenyl)-propionate] and processing aids, i.e. 0.05 wt % calcium stearate.
Blown films were produced on a single screw extruder with a barrel diameter of 70 mm and a round-section die of 200 mm with 1 mm die gap in combination with a monolip cooling ring and internal bubble cooling (IBC). Melt temperature was 210° C. in the die; the temperature of the cooling air was kept at 15° C. and the blow up ratio (BUR) 3:1. A film thickness of 40 μm was adjusted through the ratio between extruder output, takeoff speed and BUR.
Cast films were produced on a single screw extruder with a barrel diameter of 52 mm and a slot die of 800×0.5 mm in combination with a chill- and a takeup-roll. Melt temperature was 240° C. in the die; the chill-roll was kept at 15° C. and the takeup roll at 20 ° C. A film thickness of 50 μm was adjusted through the ratio between extruder output and takeoff speed.
The films were tested and analysed as is outlined and described above. The results are shown in table 2.
Example E1 is according to the invention, examples C1 to C3 are comparative examples.
TABLE 2
Example
E1
C1
C2
C3
Material
polymer 1
polymer 2
polymer 3
polymer 4
Blownfilm
Blownfilm
Blownfilm
Castfilm
Tensile test
tens. Mod.
MPa
925.7
912.5
1440
670
md
yield str.
MPa
26.8
25.55
36.38
18.7
yield elong.
%
12.54
12.47
8.5
6.6
tens. Str.
MPa
50.21
52.84
60
33.8
elong.at break
%
581.32
656.75
681
715.6
Tensile test
tens. Mod.
MPa
972.5
911.2
1380
693
td
yield str.
MPa
24.42
23.97
35.45
18.8
yield elong.
%
8.75
10.35
7.7
6.4
tens. Str.
MPa
34.31
39.04
32.1
31.8
elong. at break
%
665.07
728.21
9.71
730
Elmendorf
md
N/mm
3.36
3.94
1.8
7.8
td
N/mm
9.95
9.64
12.3
25.5
Gloss
outs.
%
70.8
16.3
1
120
inns.
%
65.3
30
1
115
Haze
%
3.96
10.33
64
2.2
The film from example E1 has excellent stiffness, i.e. tensile modulus is in both directions higher than for C2. Drawability (elongation at break) is comparable to that of the comparative examples and, of course, drawability of the homopolymer blown film in transverse direction is virtually non-existent. The optical properties gloss and haze of E1 are remarkably improved compared to C1.
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The invention refers to polypropylene blown films which are characterised by excellent optical and mechanical properties. The polypropylene composition used for the films contains nucleating agents.
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BACKGROUND OF THE INVENTION
The invention relates to a device for fixing a printed circuit board or card to a casket-like support having been equipped with inside channels or slots for guiding the circuit board in a pair of parallel channels when mounting the circuit board to the support, or when dismantling the board from the support.
Regarding electronic equipment which is exposed to vibrations and shaking, the circuit boards have to be fixed to the support. Then it comes naturally to fix the circuit boards in the channels by means of locking or clamping devices, for instance set screws or spring loaded clamps.
In many cases these provisions are satisfactory, despite that they often require use of structures that enhance the price and also delay eventual replacement of boards. In other cases, on the contrary, in which not even very small relative displacements between board and support can be allowed, said provisions are contingent on severe requirements to the material's resistance against deformation after continual mechanical strain. In general, such locking means are aimed at, that result in minimum inconvenience when used.
Thus, there exists a need for safe and simple locking means for printed circuit boards which are mounted in channels to a casket-like support, especially in connection with movable electronic equipment which, because of the circumstances, also may be subjected to rough treatment when being used.
SUMMARY OF THE INVENTION
The object of the invention is to procure a locking means which is safe under all of the conditions for which the electronic equipment is constructed, and which makes mounting and dismantling of the circuit board to, respectively from, the support by means of simple manipulations.
This is obtained by means of the device according to the invention, which device is characterized by an elastic material, for instance a rubber band, which partly occupies the volume of the channels and which in extended condition along the channel direction allows said guiding because of its reduced cross section, and which in relaxed condition fixes the circuit board to the support.
DESCRIPTION OF THE INVENTION
The invention is now to be explained by means of a preferred example of performance. It is referred to the drawing, where:
FIG. 1 is a perspective sketch of a casket-like support and a printed circuit board or card which is fixed thereto according to the invention, and
FIG. 2 in a section through the board support of FIG. 1 illustrates the manner of operation of the fixing device according to the invention.
The casket-like support 1 in FIG. 1 is made from aluminium and is equipped with channels 2 for printed circuit boards 3 of which only one is shown in the figure, namely the one in the uppermost pair of channels 2". Additionally, a separate wall 4 is shown, which wall can be dismantled. In the two uppermost pairs of channels 2' and 2", there is arranged elastic ribbons or bands 5' and 5" from rubber or another elastic material which partly occupy the volume of each of its channel pairs. The lowermost band 5' is prevented from being drawn through the one pair of channels 2' by means of locking end knots 6', whereas the uppermost band 5" is locked correspondingly by means of more diligent prepared rubber heads 6". On the opposite side of the support 1 the band 5' is cut as shown, whereas the band 5" is kept as one band in order to facilitate the possibility of gripping the band by one hand when extending the band 5". It appears from the lowermost pair of channels 2 that the circuit boards are resting on a plane surface in the channels, whereas the elastic material is arranged in the upper part of the channels and exerts pressure against a part of the one surface of the circuit board. This has been shown more explicitly in FIG. 2 wherein details corresponding to details in FIG. 1 has been given corresponding numerals. The numeral 7 indicates electronic components.
Mounting and dismantling of printed circuit boards 3 to, respectively from, the support 1 is performed by extending the band as explained above, by which manipulation the cross section of the band is reduced as shown in FIG. 2a, and simultaneously guide the board 3 in its channel pair inwards from the one end of the support 1 where the band 5 is protruding from the channels 2, and guide the board 3 out from this end during dismantling. When the band 5 is released, it is contracted, by which manipulation its cross section increases and fixes the board 3 in the channels 2 as shown in FIG. 2b.
In the drawing having been described, is shown somewhat simplified, a prototype of a receiving unit of a transportable radio equipment which comprises a transmitter unit and frequency synthetizing unit as well. The various units have different chassis profiles, of which one has been shown in FIG. 1. It will be realized that this example concerning a receiving unit describes one particular application of the fixing device according to the invention, and that other performances of supports for printed circuit boards are actual as other applications. Likewise, the channel profiles can be different, and the cross section of the elastic band as well. This band can also be extended from both ends of the support.
Thus, the channels can be right angled in some performances, even though it is preferred herein that they are formed with an edge or lip in order to keep the elastic band in position. The band can have a circular cross section as shown, or an eliptic or rectangular cross section, or any other cross section suited for the profile of the channel and element. In case the elastic band is to be extended from one end only, its other end can also be clamped to the support.
Supports similar to the shown casket-like support, can be produced in large quantities in the form of extruded profiles of several meters which are then cut into desired lengths. By use of aluminium for the board supports having been described, a good electrical contact to ground is obtained, which is a problem in connection with the more usually used plastic materials which in addition become brittle at low temperatures.
It has been proved that printed circuit boards which have been fixed according to the invention, do not move relative to the support even if the equipment is exposed to shaking. Quite contrary, eventual shaking causes that the elastic material contracts even more towards complete contraction and thus fixes the element still further to the support.
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A device for fixing a printed circuit board to a casket-like support has been described. The support is equipped with pairs of inside channels for guiding and supporting the circuit board, and the device comprises an elastic material which partly occupies the volume of the channels. The elastic material allows guiding when being extended by hand, and fixes the circuit board to the support when being in a relaxed condition.
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BACKGROUND OF THE INVENTION
The present invention relates to valves having adjustable seats and, more particularly, to damper valves having seats which are variably adjustable.
Damper valves of the butterfly type are known in which a blade, usually of circular shape, is mounted for pivoting between an open position and a closed position to control the flow of fluid through the valve. A shaft about which the blade pivots is positioned diametrically with respect to the blade and is mounted for pivoting in bearings beyond the periphery of the blade. A curved blade seat is positioned in a valve body for side, that is, axial, engagement with one of the faces of the blade along the periphery of the blade.
The blade, the seat and the body can all be made of stainless steel and can be fabricated with precision. However, during handling, shipment and installation of the valves, the body can deform slightly, especially since the valves are large, typically having a diameter of several feet. Even a slight distortion, for example, on the order of less than 0.0001 inch, can have an adverse effect on the sealing ability of the valve.
The problem of loss of precise seating due to deformation of the body or other parts of the valve was overcome by the valve disclosed in U.S. Pat. No. 5,494,257 issued to the present inventor. More particularly, that patent discloses a valve with an arrangement for adjusting the seat along the length thereof to ensure a tight seal despite variations that might take place in the valve during shipping or installation, or at other times. The valve can be used with fluids at relatively high temperatures, for example, 800° F.
The arrangement of that valve includes a fixed seat member mounted on an inner surface of a valve body or base and having a side surface positioned for axial engagement with an overlapping portion of a side surface at the perimeter of the valve disk or blade. A portion of the seat on one side of the shaft is positioned on a first side of the blade, and a portion of the seat on the opposite side of the shaft is positioned on the frame for engagement with a second side of the blade. For each portion of the seat, an adjustable seat member is mounted on a surface of the fixed seat member facing the center of the frame, the adjustable seat member being movable axially relative to the fixed seat member, toward the valve blade, so that the adjustable seat member can be moved into engagement with any portion of the valve blade where the fixed seat member does not contact the blade. Bolts are provided at spaced locations along the lengths of the fixed valve seat member to secure the adjustable seat member to the fixed valve seat member when the desired precise positioning of the adjustable valve seat member has been achieved. A plurality of adjustment devices are spaced along the length of the seat and engage the adjustable seat members. Each adjustment device includes a threaded member, such as a bolt, engaging the adjustable seat member to move the adjustable seat member into sealing engagement with the blade at the needed places around the perimeter of the blade.
However, even with the improvements, there is a gas leakage through the valve which is more than an acceptable rate of leakage for some valve applications. As a result, it has been known to place two damper valves in series, each with its own blade and valve seat, in order to lower gas leakage to an acceptable level. In addition to greatly increasing cost, this practice greatly increases the space required for the installation of the valves in the conduit carrying the fluid to be controlled.
SUMMARY OF THE INVENTION
By the present invention, the leakage of gas through damper valves is further reduced by the use of two valve seats in series to define an annulus bounded by a single valve blade and the body of the valve. With such an arrangement, the differential in gas pressure across each of the seats in series is lower than the gas pressure across a single seat. As a result, the gas leakage through the valve is significantly less. In addition, the space taken up by the valve along the length of the duct in which the valve is installed is no greater than the space taken up by a similar valve having a single seat. Furthermore, the cost of a damper valve according to the present invention is much less than the cost of two single-seat valves. In order to provide zero gas leakage across the valve, the annulus can be purged with high pressure air to produce an air barrier across which a fluid having a lower pressure cannot flow.
The above objects are achieved by a valve arrangement including two valve seats arranged in series in the valve, each valve seat being in sealing engagement with the same movable valve element or blade and comprising a fixed seat member and an adjustable seat member. Each fixed seat member is mounted on an inner surface of the valve body or base and has a side surface positioned for axial engagement with an overlapping portion of a side surface at the perimeter of the valve disk or blade. Each adjustable seat member is mounted on a surface of a fixed seat member and is movable relative to the fixed seat member in a direction toward the blade. The adjustable seat members are relatively thin, from about 0.100 inches to about 0.200 inches in thickness, thereby increasing the seating pressures along the line of contact. As a result, effective sealing can be accomplished in almost all environments, including those characterized by solids accumulations or sticky substances. In some embodiments, a plurality of adjustment devices spaced along the length of the seat engage each adjustable seat member for moving the adjustable seat member and holding the adjustable seat member in a desired position on the fixed seat member.
The two seats in series define an annulus with the perimeter of the valve blade and have the effect of reducing the differential in fluid pressure across each of the two seats to a level below the fluid pressure differential of a single seat in the same application. The reduction in the gas pressure differential across each seat results in gas leakage through the valve being significantly less. The valve blade includes seal portions to define a seal with each of the valve seats.
The annulus defined between the blade, the valve body, and the two seats can be connected to a source of a high pressure gas, such as air, to produce a gas barrier. The pressure of the gas in the annulus is maintained at a level greater than the pressure of the gas on opposite sides of the blade. Where the annulus intersects the shaft upon which the blade pivots, closure elements are provided to engage the shaft and thereby reduce the leakage of the high pressure gas from the annulus.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front view of the valve according to the present invention, with the valve blade in an open position;
FIG. 2 is a side view of the valve of FIG. 1, but with the valve blade in the closed position;
FIG. 3 is an enlargement of the portion of the valve within the circle 3 in FIG. 1, showing an adjustment device for one of the valve seats, with a flange of the frame removed and the valve blade in the closed position;
FIG. 4 is a cross section taken along the line 4--4 in FIG. 3;
FIG. 5 is an enlargement of the portion of the valve within the circle 5 in FIG. 1, showing an adjustment device for the other of the valve seats, with a flange of the frame removed and the valve blade in the closed position;
FIG. 6 is a cross section taken along the line 6--6 in FIG. 5;
FIG. 7 is a cross section similar to FIG. 4, but of an alternate embodiment of the valve according to the present invention;
FIG. 8 is an enlarged detail of a shaft seal, seat and hub at the right side of the valve of FIG. 1, with the small valve seat portion removed;
FIG. 9 is a cross section taken along the line 9--9 in FIG. 8, with the small valve seat portion restored;
FIG. 10 is a cross section similar to FIG. 4, but of another embodiment of the valve according to the present invention; and
FIG. 11 is a cross section similar to FIG. 4, but of yet another embodiment of the valve according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
As can be appreciated from FIG. 1, the damper valve according to the present invention, which is designated generally by the reference numeral 10, includes a body or base 12 and bearings 14, one of which is shown, secured to the base 12. A circular valve element or blade 16 is positioned within the base 12, extending across most of the area of an inner circumference of the valve base. The blade 16 is secured to a shaft 18, which is mounted in the bearings 14 for pivoting movement relative to the base 12. A fluid pressure cylinder 20 is mounted on an exterior side of the base 12 and connected to an end of the shaft 18 for pivoting the shaft and, thereby, moving the valve blade 16 between open and closed positions.
A first valve seat includes two portions 22 and 24, both mounted on an interior surface of the base 12, one portion 22 being mounted on one side of the valve blade 16, and the other portion 24 being mounted on the opposite side of the valve blade. Seat adjustment devices 26 are mounted on an inner surface of the base 12 at intervals along the length of the valve seat portions 22 and 24. In FIG. 1, the valve seat portion 24 is shown in phantom and the seat adjustment devices associated with the valve seat portion 24 are not shown.
As can be seen in FIG. 2, the base 12 comprises a frame including a cylinder 28, radially extending flanges 30 and 32 secured at axial ends of the cylinder 28, and struts 34 connected between the flanges 30 and 32.
As can best be seen from FIGS. 3 and 4; the valve seat portion 22 includes a stationary member 36 fixed by, for example, welding to the cylinder 28, which is part of the valve base 12. A side of the stationary member 36 facing the blade 16 is machined for a precise fit with a side surface of the outer periphery of the blade, which is also machined. The stationary member 36 has a length parallel to the circumference of the cylinder 28, and the stationary member is curved to conform to the inner circumference of the cylinder. The valve seat portion 22 also includes an adjustable element 40 secured to the circumferentially inner surface of the stationary member 36 and having a width greater than the width of the stationary member. The adjustable element 40 has a radial dimension, or thickness, considerably smaller than that of the stationary member 36 and has a plurality of slots 41 extending parallel to the width of the adjustable element. The adjustable element 40 is secured to the stationary element 36 by a plurality of capscrews 42, a capscrew 42 extending through each of the slots and into a threaded opening in the stationary element to secure the adjustable element to the stationary member when the desired position of the adjustable element relative to the stationary member has been attained. Typically, the slots 41 have a length of 3/4 inch. The slots 41 and the capscrews 42 make the adjustable element 40 adjustable. A side of the adjustable element 40 facing the blade 16 is machined for precise engagement with the side of the blade. A side of the adjustable element 40 facing away from the blade 16 is engaged by an adjuster comprising the adjustment devices 26. Although the foregoing description has been made in connection with the valve seat portion 22, it is understood that the valve seat portion 24 has the same structure.
Each adjustment device 26 includes a base member 44, a threaded aperture associated with the base member 44 and a threaded element 46 cooperating with the threaded aperture. In the embodiment of FIG. 4, the threaded aperture is contained in a nut 48 welded to a side of the base member 44. With this arrangement, the base member 44 has a bore in alignment with the threaded aperture in the nut 48 and large enough that the threaded element can be slid axially through the bore. The threaded element 46 is a bolt whose head is in engagement with the adjustable element 40.
As can be seen from FIGS. 1, 5 and 6, a second valve seat includes two portions, both mounted on an interior surface of the base 12, one valve seat portion 50 being mounted on one side of the valve blade 16, parallel to and spaced from the valve seat portion 22 of the first valve seat. The other valve seat portion (not shown) of the second valve seat is mounted on the opposite side of the valve blade 16 of the second valve seat is mounted on the opposite side of the valve blade 16 from the valve seat portion 50, and parallel to and spaced from the valve seat portion 24 of the first valve seat. Seat adjustment devices 52 are mounted on an inner surface of the base 12 at intervals along the length of the first and second valve seat portions, spaced along that length from the seat adjustment devices 26 for the first valve seat.
As can best be seen from FIGS. 5 and 6, the valve seat portion 50 is positioned between the cylinder 28 and the periphery of the main body of the valve blade 16 in a direction parallel to the central plane of the valve blade when the valve blade is in a closed position. The valve seat portion 50 includes a stationary member 54 fixed by a plurality of bolts 56 to the cylinder 28. The valve blade 16 includes a sealing flange 58 connected by bolts 60 to the side of the main body of the valve blade 16 opposite to the side engaged by the stationary member 36 and the adjustable element 40 of the first valve seat. The sealing flange 58 extends the length of the valve seat portion 50 of the second valve seat and projects into the space between the cylinder 28 and the rest of the valve blade 16 for engagement by the second valve seat. A side of the stationary member 54 facing the sealing flange 58 is machined for a precise fit with a side surface of the sealing flange which is also machined. The stationary member 54 has a length parallel to the circumference of the cylinder 28, and the stationary member is curved to conform to the inner circumference of the cylinder. The second valve seat portion 50 also includes an adjustable element 62 secured to the circumferentially inner surface of the stationary member 54 and having a width greater than the width of the stationary member. The adjustable element 62 has a radial dimension, or thickness, considerably smaller than that of the stationary member 54 and has a plurality of slots (not shown) extending parallel to the width of the adjustable element, like the slots 41 of the adjustable element 40. The adjustable element 62 is secured to the stationary element 54 by, for example, welding. A capscrew 64 extends through each of the slots to secure the adjustable element to the stationary member when the desired position of the adjustable element relative to the stationary member has been attained. A side of the adjustable element 62 facing the sealing flange 58 is machined for precise engagement with the sealing flange. A side of the adjustable element 62 facing away from the sealing flange 58 is engaged by the adjustment devices 52. Although the foregoing description has been made in connection with the valve seat portion 50, it is understood that the unillustrated valve seat portion of the second valve seat has the same structure.
Each adjustment device 52 includes a threaded aperture associated with the stationary member 36 of the first valve seat and a threaded element 66 cooperating with the threaded aperture. In the embodiment of FIGS. 5 and 6, the threaded aperture is contained in a nut 68 welded to a side of the stationary member 36 facing away from the valve blade 16. With this arrangement, the stationary member 36 has a bore 70 in alignment with the threaded aperture in the nut 60 and large enough that the threaded element can be slid axially through the bore. The threaded element 66 is a bolt whose head is oriented distal to the valve blade 16. The end of the bolt opposite to the head extends into the space between the cylinder 28 and the main body of the valve blade 16 and into engagement with the adjustable element 62 of the second valve member.
The cylinder 28, the valve blade 16 when it is closed, and the first and second valve seats define a chamber 72 for containing a gas, such as air, under a pressure greater than the pressure of the fluid controlled by the damper valve 10. Each chamber 72 extends around substantially half of the perimeter of the valve blade 16 from the portion of the shaft 18 extending through one side of the blade 16 to the portion of the shaft 18 extending through the opposite side of the blade 16. One of the chambers 72 extends along the top of the blade 16 and the other chamber 72 extends along the bottom of the blade 16, when the blade 16 is closed. With this arrangement, the ability of the damper valve 10 of the present invention to prevent leakage past the valve of the fluid the valve controls is further enhanced. Gas under pressure is communicated to the chamber 72 through at least one opening 74 in the cylinder 28 from an external gas supply plenum defined by a plenum member 76 secured to the exterior of the cylinder 28.
As can be seen from FIG. 7, in one alternate embodiment, a damper valve 10 of the present invention, a valve blade 16 has a main portion 16a, to which a rim 16b is secured, for example, by welding. The rim 16b is thicker than the main portion 16a. The first valve seat engages and seals with the rim 16b, and the rim 16b can be machined for precise seating. In addition, the sealing flange 58 is secured to the rim 16b. In all other respects, the embodiment of FIG. 7 is the same as the embodiment of FIGS. 1-6.
As can be seen from FIGS. 9 and 10, where the chamber 72 intersects with the shaft 18, closure seats 78 and 80 in the form of plates welded to the ends of the stationary members 36 and 54, respectively, engage the circumference of the shaft 18 to form seals at the ends of the chamber 72.
As can be seen from FIG. 10, the stationary member 36' of the valve seat portion 22' can comprise an angle member having a first leg 36a perpendicular to and fixed to the cylinder 28 by, for example, welding. A second leg 36b defines a support for the adjustable element 40 and defines the slots 41 for receiving bolts 42' to which nuts 38 are secured.
The adjustment devices 26 and 52 have been omitted from the embodiment of FIG. 10, although they can be provided if desired. The plenum member 76 is also omitted. Instead, the gas under pressure is fed directly to the chamber 72 through the opening 74 in the cylinder 28. As an option, the plenum member 76 can be used with the embodiment of FIG. 10. In all other respects, the embodiment of FIG. 10 is the same as the embodiment of FIGS. 1-6.
The embodiment of FIG. 11 is like the embodiment of FIG. 10, except that the valve-seat portion 50 of the second valve seat is positioned under the adjustable element 40 of the first valve seat. Thus, the first and second valve seats are in alignment with one another in a direction parallel to the central plane of the valve blade 16 when the valve blade is in a closed position. The second valve seat forms a seal with a side of the main body of the valve blade 16. When the valve blade is in its closed position, the stationary member 36 is spaced from the valve blade sufficiently, about 1 inch, to allow tools, such as a wrench and a crowbar, to be inserted between the stationary member and the valve blade. With such a space, the adjustable element 40 can be in a position, shown in solid lines in FIG. 11, in which the adjustable element is also spaced from the valve blade 16. In that position of the adjustable element 40, a ratchet wrench is inserted in the space to loosen the capscrews 64 fixing the adjustable element 62 in place on the stationary element 54. A crowbar is inserted into the space to lever the adjustable element 62 into contact with the valve blade 16, and the capscrews 64 are tightened. The adjustable element 40 is moved relative to the stationary member 36' to the position shown by the dashed lines to engage the valve blade 16. The bolts 42' are tightened to fix the adjustable element 40 in its seating position.
As can be appreciated from, for example, FIG. 4, during manufacture, the valve seat portions 22 and 24 are precisely fixed in place using the capscrews 42 to provide precise engagement between the facing machined faces of the stationary members 36 and the blade 16. When the damper valve 10 has been installed, the fit between the valve seat portions 22 and 24 and the blade 16 are checked along the entire length of the valve seat portions. If any gaps are detected, the capscrews 42 are slightly loosened and the threaded element 46 turned to move the adjustable member 40 into engagement with the face of the blade 16 where there had been a gap. This is done on the adjustment device or devices 26 lying closest to the gaps. When precise engagement is provided, the capscrews 42 are tightened and, where a lock, such as a jamb nut 82, is used on the threaded element 46, the jamb nut is also tightened against the base member 44, to lock the adjustable member 40 in position. This procedure is followed for all gaps along the lengths of the valve seat portions 22 and 24.
Having thus described the present invention and its preferred embodiments in detail, it will be readily apparent to those skilled in the art that further modifications to the invention may be made without departing from the spirit and scope of the invention as presently claimed.
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A damper valve includes a base, a valve blade pivotally mounted on the base and two serially arranged valve seats. Each valve seat comprises adjustable valve seat portions on opposite sides of a pivot axis of the valve blade, the valve seat portions being positioned on opposite sides of the blade. Each valve seat portion includes a stationary member fixed to the base, an adjustable element movable relative to the stationary member, and bolts fixing the adjustable element to the stationary member. Adjustment devices are provided for moving each adjustable element toward the valve element to provide a precise fit along the entire length of the valve seat. The valve seats and the valve blade define an annulus which can contain gas at a higher pressure than the fluid controlled by the valve, so that none of the controlled fluid flows past the valve.
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CROSS-REFERENCE TO RELATED APPLICATIONS
Pursuant to 35 U.S.C. §119(e), this application claims priority to U.S. provisional patent application No. 60/846,674, filed Sep. 22, 2006, the entire disclosure of which is incorporated herein by reference.
FIELD OF THE INVENTION
This invention relates generally to a device for tapping threads into various substrates with a wide range of hardness and machinability with a decrease in cutting pressure and an increase in surface finish and tap life.
BACKGROUND OF THE INVENTION
Existing thread cutting taps are generally designed and manufactured to perform within a relatively narrow range of hardness and machinability. This requires the user to maintain an inventory of several taps of the same size to accommodate different substrate materials in order to maximize the performance of the taps and the quality of the female threaded holes. These taps, which include helical flute taps and straight flute taps, often produce poor surface finishes and high cutting pressure. Right or left-handed helical flute taps have one sharp rake angle and one dull rake angle on the thread teeth cutting edges. In both cases, the side opposite the positive rake angle (sharp cutting edge) must be a negative rake angle (dull cutting edge). Negative rake angles increase cutting pressure and drag on the tap leading to tap breakage. Straight flute taps have only 0° rake angles on both upper and lower cutting edges of the thread teeth which also increase cutting pressure that leads to tap breakage.
For the foregoing reasons, there is a need for a device for tapping threads that overcomes the significant shortcomings of the known prior art as delineated hereinabove.
BRIEF SUMMARY OF THE INVENTION
In one aspect, an embodiment of the invention provides a double helix thread cutting tap with both right-handed and left-handed helical chip removal flutes. In one embodiment, the double helix thread cutting tap includes at least two opposing left-handed flutes and two opposing right-handed flutes. The double helix thread cutting tap places a positive rake angle on all sets of thread cutting teeth for optimum performance and minimal cutting pressure. This translates into longer tap life and better surface finishes as well as the ability to cut all substrates with one tap.
The thread cutting tap described herein is capable of cutting both hard and soft metals as well as those that have varying degrees of machinability. This is extremely valuable to the user because of the many different metals, plastics, bones, wood and other substrates that may require female threads to be cut in order to accept a threaded fastener of some type.
In one aspect, the double helix thread cutting tap overcomes the negative aspects of the existing taps, such as high cutting pressure, poor surface finishes, and the need to have a special tap for each type of material to cut threads into. In another aspect, the double helix thread cutting tap effectively reduces cutting pressure by providing sharp cutting edges on alternating upper and lower cutting surfaces of the opposing threaded margins. In yet another aspect, the double helix thread cutting tap makes it possible to cut both hard and soft materials by having low hook angled cutting teeth faces separated by high hook angled cutting teeth faces. In a further aspect, and in addition to benefit of double helix thread cutting tap's improved cutting ability is that it also provides a better surface finish on both upper and lower thread surfaces of the finished female threaded hole. The improved surface finish provides a better contact surface for the fastener which translates into higher clamping forces and resistance to loosening and backing out.
Accordingly, it should be apparent that numerous modifications and adaptations may be resorted to without departing from the scope and fair meaning of the claims as set forth hereinbelow following the detailed description of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows an isometric view of one example of an embodiment of a thread cutting tap with two sets of right-handed, opposing helical chip removal flutes.
FIG. 2 shows a side view of the tap of FIG. 1 with right-handed helical flutes.
FIG. 3 shows a side view rotated 90 degrees from FIG. 2 with a left-handed helical flute ground into the leading end of the tap intersecting the right-handed helical flute.
FIG. 4 shows an end view of the tap of FIG. 3 and opposing left- and right-handed helical chip removal flutes with details of the low hook angles and high hook angles of the thread cutting teeth faces.
FIG. 5 shows a close-up of a left-handed helical flute with emphasis on the positive rake angle of the upper cutting surfaces of the cutting teeth.
FIG. 6 shows a close-up of a right-handed helical flute with emphasis on the positive rake angle of the lower cutting surfaces of the cutting teeth.
DETAILED DESCRIPTION OF THE INVENTION
The description and figures describe an embodiment of the tap having right-handed cutting surfaces that only cut when rotated in a clockwise direction. In another embodiment, the tap may have left-handed cutting surfaces that only cut when rotated in a counterclockwise direction.
Considering the drawings, wherein like reference numerals denote like parts throughout the various drawing figures, reference numeral 10 is directed to a thread cutting tap.
As shown in FIGS. 1 , 2 , and 3 , one embodiment of the thread cutting tap 10 is defined by upper driving end 11 , intermediate shank 14 , threaded portion 12 and bottom end 19 . Threaded portion 12 , having cutting teeth 42 , includes a plurality of right-handed, helical chip removal flutes 15 and 16 dispersed diametrically opposite each other around the circumference of threaded end 12 . Cutting edges 13 are form relieved to provide sharpened cutting edges.
FIG. 2 shows right-handed helical flutes 15 and 16 with a starting point at the bottom end 19 and traversing through the threads dissipating into intermediate shank 14 forming cutting edges and chip removal flutes. Flutes 15 are uniform in shape. A front elevation view of partial left-handed helical flute 17 in flute 16 is shown at end 19 of right-handed flutes 16 only. Radial form relief 18 is ground to create land 20 ( FIG. 3 ) located adjacent to end 19 between flutes 15 and 16 to provide cutting edge relief so the tap can begin cutting as it engages the hole to be tapped.
Partial left-handed helical flute 17 (see FIG. 3 ) is shown in an overhead view at end 19 of right-handed helical flutes 16 . Right-handed helical flutes 15 do not contain partial left-handed helical flute 17 .
Right-handed helical flutes 15 (see FIG. 4 ) are interspersed between right-handed helical flutes 16 , such that flutes 15 alternate with flutes 16 around the circumference of threaded portion 12 . Only right-handed flutes 16 have additional partial left-handed helical flutes 17 shaped to create cutting edges 25 . Right-handed helical flutes 15 create cutting edges 26 . Cutting edges 26 of flutes 15 are formed to create a high hook angle (about +7 to about +15°). Partial left-handed helical flute 17 is ground into right-handed helical flute 16 at end 19 to create low hook angles (about 0 to about +5°).
The high hook angle of cutting edge 26 is formed to cut soft materials such as aluminum and soft steel. The low hook angle of cutting edge 25 is formed to cut tougher materials such as cast iron, ductile iron and stainless steel.
Tap 10 includes an equal number of right-handed helical flutes 15 and right-handed helical flutes 16 containing partial left-handed flutes 17 . Tap 10 may be made with any number of flutes 15 and flutes 16 , as long as there are equal numbers of flutes 15 and flutes 16 and they alternate around threaded portion 12 .
FIG. 5 is for reference only to show a simple view of a left-handed helical chip removal flute 37 cut into threading tap 38 , creating upper cutting edges 30 and lower cutting edges 31 . Because of the way that helical chip removal flute 37 bisects through the thread teeth at an angle to the longitudinal axis of the tap, upper thread tooth flanks 27 and cutting faces 28 converge, producing upper thread teeth cutting edges 30 which form rake angles less than 90 degrees or sharp cutting edges. This causes the lower thread tooth flanks 29 to converge with cutting faces 28 , producing lower thread teeth cutting edges 31 with rake angles greater than 90 degrees or dull cutting edges.
FIG. 6 is for reference only to show a simple view of a right-handed helical chip removal flute 39 cut into threading tap 40 , creating upper cutting edges 35 and lower cutting edges 36 . Because of the way that right-handed helical chip removal flute 39 bisects through the thread teeth at an angle to the longitudinal axis of the tap, upper thread tooth flanks 32 and cutting faces 34 converge, producing upper thread teeth cutting edges 35 which form rake angles greater than 90 degrees or dull cutting edges. This causes the lower thread tooth flanks 33 to converge with cutting faces 34 , producing lower thread teeth cutting edges 36 with rake angles less than 90 degrees or sharp cutting edges.
As described above, tap 10 has a high hook angle on at least two opposing thread teeth faces of the right-handed helical flutes and a low hook angle on at least two opposing thread teeth faces of the partial left-handed helical flutes. With radial relief on all leading edges nearest end 19 , tap 10 will cut easier and last longer than existing taps and can be used in most soft substrates, such as bone, plastic, aluminum, brass, and bronze, to harder and tougher substrates, such as stainless steel, cast iron, ductile iron, titanium, and hardened steels.
Thread cutting tap 10 can be used with any thread profile, including, but not limited to, American standard threads, metric threads, Buttress threads, hook threads, dovetail threads, and self locking threads.
Thread cutting tap 10 is used by holding it by shank 14 , placing threaded portion 12 into a drilled hole of a preferred diameter and rotating it until the cutting edges dig in and cut the thread form into the side walls of the drilled hole. The rotation continues until tap 10 has succeeded in cutting the preferred thread profile to a desired depth. The rotation is then reversed and tap 10 is backed out of the drilled hole revealing the female helical threads within the drilled hole that can receive a male threaded fastener of a preferred embodiment.
The invention has been described above with the reference to the preferred embodiments. Those skilled in the art may envision other embodiments and variations of the invention that fall within the scope of the claims.
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The invention includes a double helix thread cutting tap with both right-handed and left-handed helical chip removal flutes. The double helix thread cutting tap places a positive rake angle on all sets of thread cutting teeth for optimum performance and minimal cutting pressure.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This non-provisional application claims the benefit of U.S. Provisional Patent Application No. 60/574,072, entitled “Retrieval Device,” filed May 25, 2004, which is hereby incorporated in its entirety.
FIELD OF THE INVENTION
The present invention relates to a retrieval device and more particularly to a endoscopic retrieval device for retrieving objects from within a human subject.
BACKGROUND OF THE INVENTION
Endoscopic retrieval or removal devices are known in the art and are conventionally used to recover objects from inside a human subject. Such objects may include severed human tissue, foreign objects, or food bolus. Some typical devices include forceps or clasps to grab objects. Certain devices of this type are not well-suited for retrieving rounded or blunt foreign objects such as coins, marbles and batteries because they are difficult to hold secure. Further, if a foreign object is dropped near the trachea during the removal process the results can be catastrophic for the patient.
Devices using netting have been developed to capture rounded or blunt objects. U.S. Pat. No. 6,814,739 to Secrest et al., which is incorporated herein by reference in its entirety, discloses a device for retrieving an object from within a subject. In the use of devices having netting, and it is believed in the use of other devices, physicians have experienced difficulty in recovering certain objects, such as for example, impacted food bolus from the esophagus. A bolus is a mass of masticated or chewed food. In some cases, the bolus becomes impacted in the esophagus due to disease states, and other disorders and consequently, does not pass into the stomach. An object of this type may be more difficult to position over or be more heavier than the human tissue or foreign object for which these type of devices were designed. This problem is especially apparent when working in relatively tight places within the body. As a result, netting support collapses and does not retain its shape in a deployed position when holding the captured object.
To solve these and other problems, the present invention uses a flat wire to make the loop that supports the retrieval net. The flat wire provides a wider net capacity to entrap the bolus and is firmer, more rigid and less likely to collapse. As such, the loop maintains its shape in use, particularly when used in narrow lumens like the esophagus. The flat wire can be formed into a polygon shape, is more likely to be resistant to collapse and can include distal tip structure designed to further resist collapse and promote expansion.
SUMMARY OF THE INVENTION
In an illustrated embodiment of the invention, a device for retrieving objects, such as for example, impacted food bolus, foreign objects, and severed human tissue, is disclosed. The device is for use within an instrument channel of an endoscope during endoscopic medical procedures.
The device includes a body, a handle fixed to and movable relative to the body, an elongated tube fixed to the body, a link extending substantially through the tube and having a first end fixed to the handle and a second end remote from the body, and a net including a loop and a net element. The loop is expandable and collapsible by action of the handle relative to the body.
The loop retains an expanded configuration when deployed, allowing for relatively heavy objects to be disposed within the net element. The loop may be constructed from, for example, a stainless steel flat wire or other suitable material having a tensile strength greater than 300,000 psi.
The present invention is an improvement over prior art designs because the loop supporting the net is less likely to collapse under the weight of an object such as an impacted food bolus. Moreover, the wire opens wider than prior art designs when used in narrow lumens like the esophagus. The device allows for the capture of relatively heavy objects and reduces the risk associated with the procedure. Once an object is secured within the net element, the wire loop advantageously resists collapse.
Further features and advantages of the invention will become apparent from the following detailed description made with reference to the accompanying drawings.
The Detailed Description of the Invention merely describes preferred embodiments of the invention and is not intended to limit the scope of the claims in any way. Indeed, the invention as described by the claims is broader than and unlimited by the preferred embodiments, and the terms in the claims have their full ordinary meaning.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a retrieval device constructed in accordance with an embodiment of the present invention;
FIG. 2 is a cross-sectional fragmentary view of the distal portion of the device illustrated in FIG. 1 , showing a net in a stored position within a tube;
FIG. 3 is an alternative view of the portion illustrated in FIG. 2 , showing the net in a deployed position outside of the tube;
FIG. 4 is an exploded perspective view of the designated circular section of FIG. 1 , showing detail of the net element and the distal end of the loop;
FIG. 5 is a exploded fragmentary top view of the net of a retrieval device, showing an alternative structure of the distal end of the loop;
FIG. 6 is a exploded fragmentary top view of the net of a retrieval device, showing yet another alternative structure of the distal end of the loop; and
FIG. 7 is a perspective view of a distal portion of the device illustrated in FIG. 4 , showing a food bolus captured within the net.
DESCRIPTION OF THE INVENTION
A device for retrieving an object from within a human subject is disclosed. The device is designed for use within an endoscope and may be used for retrieving relatively heavy objects within relatively tight lumens, such as for example, impacted food bolus from the esophagus. In discussing the device, the terms distal and proximal are used with respect to the operator's hand. In other words, when the device is used within the auxiliary channel of an endoscope or similar device, the proximal and distal orientation are relative to the surgeon or operator of the device.
Referring now to the drawings, FIG. 1 is a perspective view of a retrieval device 10 constructed in accordance with an embodiment of the present invention. The device includes a support base or elongated body 14 . The body includes a ring 16 at a proximal end. The device 10 also includes a handle 18 having two rings 20 . The handle 18 is mounted over an interior section 15 of the body 14 and is movable relative to the body in the direction A 1 as illustrated. For example, an operator may place a finger in each of the rings 20 and thumb of the same hand in the body ring 16 . By moving one's fingers in the direction A 1 , an operator can move the handle 18 relative to the body 14 . In contrast, the handle can be slid a direction opposite A 1 by pulling one's finger's towards one's thumb.
The device includes an elongated inducer member or tubular member 24 having a first end 26 fixed to the body 14 and a second end 28 . The tubular member 24 and the body are a fixed support assembly for the moving parts of the device. The tubular member 24 may be any suitable small diameter tube formed of a non-reactive low-friction plastic material, such as for example, polytetrafluouroethylene. The tubular member 24 defines a passage with an opening 30 at the tubular member second end 28 , as best seen in FIG. 2 which shows cross-sectional view of a distal portion of the device 10 .
A motion transmitting link 34 is connected to the handle 18 . The link 34 has a first end 36 fixed to the handle 18 and a second end 38 remote from the body 14 . As shown in the drawings, the link extends substantially through the tubular member 24 passage. The link may be constructed of any suitable rigid material.
Still referring to FIG. 1 , the device also includes a net 50 . The net is used by the operator to capture and retrieve objects from within a human subject. The net 50 includes a loop 52 and a net element 54 secured to the loop 52 . The loop may be inserted through a mouth section of the net or otherwise connected in any conventional manner known in the art. As shown in several Figures, a net tether 57 at the distal end of the net anchors the net element 54 to the loop 52 at a distal end 53 of the loop.
As discussed, the net is designed for movement between two positions. FIGS. 1 and 2 shows the net 50 in these two possible positions. FIG. 1 shows the net 50 in a deployed position. In this position, the net has a length L 1 and a width W 1 . The ratio of L 1 and a width W 1 is less than prior art designs, meaning the device has increased width capacity. FIG. 2 is a cross-sectional view of a distal portion of the device 10 , showing the net in a stored position within the tube 24 . In this position, the net has a length L 2 which is considerably longer than L 1 . As shown in FIG. 2 , the net 50 is disposed adjacent the link 34 second end 38 for deployment and retrieval through the tubular member passage opening 30 . By movement of the handle 18 relative to the body 14 , the net is movable between either the deployed or stored positions.
Referring now to FIG. 3 , the net 50 is illustrated in a deployed position and fully expanded outside of the tube 24 second end 28 . The net element 54 may be constructed of any suitable light weight material, such as for example, nylon mesh string 56 , as best seen in FIG. 4 . The net element 54 has a centrally located object receiving pouch section 58 . To be discussed further in greater detail, captured objects rest within this section as shown in FIG. 7 .
As discussed, the net 50 includes a loop 52 . The loop 52 acts as a support for the net 50 when deployed. The loop 52 is resiliently movable between a collapsed position shown in FIG. 2 to an expanded position shown in FIG. 3 by operator action of the handle relative to the body. A distal end 53 includes structure to resist collapse during use.
Referring now to FIG. 4 , an exploded perspective view of the designated circular section of FIG. 1 is shown. In the embodiment shown, the loop 52 is a flat wire constructed of a resilient material, such as for example, 304 stainless steel. The loop material may be constructed from a material having a tensile strength greater than 300,000 psi.
Referring again to FIG. 3 , the loop 52 includes collapse-resistant bends 60 , with the straight segments between the bends 60 forming a polygon shape. As apparent from FIG. 3 , a maximum width W 1 of the loop 52 is defined by two opposing linear segments of the polygon. As shown, the two opposing linear segments are also parallel. In regard to these two linear segments, the distance along a longitudinal axis of the loop 52 from a distal most point of each linear segment to a distal most point of the loop is less than the distance from a proximal most point of each linear segment to a proximal most point of the loop. In other words, FIG. 3 illustrates a majority of each of the two opposing linear segments disposed closer to the distal end of the loop 52 as compared to the proximal end of the loop 52 . This positioning is apparent from their relative placement along the length L 1 of the loop 52 .
Other features of the invention are apparent from FIG. 3 . As previously stated, the polygon shape of the support loop defines a pair of lengthwise extending parallel linear wire segments that define a maximum width W 1 of the support loop 52 . Additional linear wire segments which extend distally from an end of each of the parallel wire segments taper distally to connect with the spiral wire structure. Additional linear wire segments which extend proximally from an end of each of the parallel wire segments taper proximally to connect within the introducer passage opening.
The loop 52 is illustrated having a first and a second support loop portion in FIG. 3 . The first support loop portion is “V” shaped and flares outwardly in a distal direction from the elongated hollow tube 24 , with a pair of lengthwise parallel wire segments at a widest portion W 1 of the “V” shape. The second support loop portion is “V” shaped and flares outwardly in a proximal direction from the spiral spring 64 to connect with a distal end of each parallel wire segment of the lengthwise parallel wire segments. The collapse resistant bends 60 and the linear wire segments located between the spiral spring and each of the parallel wire segments are oriented to “V” inward, as seen in FIG. 4 , into the net. Also, the second support loop portion is shorter along a net length L 1 than the first support loop portion.
The illustrated device in FIGS. 2 and 3 includes several features that promote expansion and prohibit collapse when an object is held within the net element or the device is used in a relatively tight lumen. The loop 52 includes several collapse-resistant bends 60 . The location of the bends 60 act as memory points and are retained by the loop through multiple deployments. These bends are constructed such that the loop forms a polygon shape when deployed. As shown, the loop 52 forms a general hexagon shape. It is believed that the polygon shape is more resilient and less likely to collapse when an object is held within the net or when retrieving an object within a narrow lumen. It should be understood by those with ordinary skill in the art that the polygon shape shown in FIG. 3 is for exemplary purposes only, and other polygon shapes can be used in the practice of the present invention.
As best shown in FIG. 4 , the loop 52 further includes a 360 degree curved portion 64 disposed at a distal end 53 of the loop. It is believed that this curved portion 64 acts as a spring tip to further prohibits collapse when an object is held within the net. It is also believed that this spring tip 64 acts to promotes polygon segments 65 a , 65 b to remain apart during deployment. This feature is beneficial in tight lumens, such as for example, the esophagus.
Several other embodiments include alternative shapes and structures of the distal end of the loop. FIG. 5 shows the distal end of the support wire in an alternative shape. The loop 52 is bent to form a protruding tip 68 . It is believed that this shape promotes polygon segments 69 a , 69 b to remain apart during deployment and use.
Referring to FIG. 6 , an exploded fragmentary view of other alternative structure of the distal end 53 of the loop 52 is shown. As in the embodiment shown in FIG. 5 , the distal end of the loop 52 is bent into a protruding tip 68 . Over the spring tip 68 , a tip cap member 70 is press fit or connected by another suitable technique. The tip 70 may be constructed of plastic or any other suitable material. The tip 70 includes an aperture 72 therethrough as a distal end. As shown, the net anchor 57 is placed through the aperture and tied off to secure the net element 54 to the loop 52 . A corresponding anchor 59 can be used to tie off the net element 54 to the link 34 on the proximal side of the wire loop connector.
In an exemplary operation of the device, the patient is intubated with an endoscope. The device 10 is inserted through an auxiliary channel of the endoscope, either before or after intubation. The device is inserted with the net 50 in a stored position as shown in FIG. 2 . The surgeon utilizing the optical features of the endoscope will identify the object for removal. After identification, the surgeon with manipulate the handle 18 with respect to the base 14 to deploy the net 50 into the position shown in FIG. 1 .
The surgeon will manipulate the object into the receiving pouch 58 by one of a variety of techniques, including the use of additional endoscopic tools. The surgeon may manipulate the snare over the top of the object and enclose the net, or manipulate the snare under the object and enclose the net. Further, the surgeon may use the net as a scoop, relying on the increased lateral stability of the device over prior art designs. Once the object is within the pouch, the surgeon may manipulate the handle with respect to the body to slightly close the net around the object. FIG. 7 is a perspective view of a distal portion of the device illustrated in FIG. 4 , showing a food bolus captured within the net. In this position, the loop retains an expanded configuration with an object 80 retained within the pouch section 58 . The endoscope now may be removed from the patient with risk of loss of the food bolus greatly reduced as compared to prior art devices.
While several embodiments of the invention has been illustrated and described in considerable detail, the present invention is not to be considered limited to the precise construction disclosed. Various adaptations, modifications and uses of the invention may occur to those skilled in the arts to which the invention relates. It is the intention to cover all such adaptations, modifications and uses falling within the scope or spirit of the claims filed herewith.
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An endoscopic surgical device for retrieving objects, such as for example, severed human tissue, foreign objects or impacted food bolus, from within a subject is disclosed. The device includes a body and handle movable relative to the body, a tubular member fixed to the body, a link having a first end fixed to the handle and a second end remote from the body, and a net including a loop and a net element. The loop is expandable and collapsible by action of the handle relative to the body. The loop retains an expanded configuration when deployed to allow for the capture certain objects that were otherwise difficult to capture because of positioning, location, or object characteristics. The loop may be constructed of flat wire and form a polygon shape when deployed. Structure at the distal end of the loop may propel and retain the loop into an open position when in use in narrow organs such as the esophagus.
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TECHNICAL FIELD
[0001] The present invention relates to composite cement panel for use in a roof deck or similar structure, and a fabricating method of the cement panel.
BACKGROUND ART
[0002] FIG. 1 illustrates a typical construction 100 of a cladding construction system of a concrete roof deck 102 . A cement sand base 104 is formed over the roof deck 102 , the base 104 being screed to form a slope or slope-to-fall gradient to create a drainage fall into a drain 106 and downpipe 108 . A waterproof membrane 110 is laid over the cement sand base 104 , interrupted only by downpipe 108 , and extending a height 112 of 300 mm up the inside surface of walls 114 . Where the deck 102 meets some walls 114 , the transition of the waterproof membrane from the horizontal surface to the vertical surface may be effected by use of waterproof filler such as poly foam 116 . A thermal insulating layer 118 is constructed on top of the membrane 110 , the layer 118 comprising extruded polystyrene insulation board of 50 mm thickness. A separation fleece layer 120 overlies the thermal insulating layer 118 . Finally an overlying protective screed concrete layer 122 of 75 mm thickness is provided, comprising 4.5 m by 4.5 m panels separated by joints filled with bituminous compound. Plastering 124 is applied to walls 114 .
[0003] The thermal insulating material 118 reduces heat transfer through the concrete roof deck 102 into the building below. The protective cement screed 122 protects the thermal insulating material 118 and the waterproofing membrane 110 , and bears the human traffic on the roof deck. Such a construction 100 is constructed in-situ on site, with an expansion joint provided at regular intervals.
[0004] Construction 100 suffers from a range of problems. The expansion joints in concrete screed layer 122 are a weak point in the construction and a source of leaks. Residual water becomes lodged between the thermal insulating material 118 and the waterproofing membrane 110 after rain. When exposed to heat from the sun, the water expands and evaporates, exerting pressure on the thermal insulating material 118 which in turn exerts pressure onto the protective screed concrete 122 . Both the protective screed concrete 122 and thermal insulating material 118 will generally crack due to such stress, leading to leakage and/or “sickness” in the construction 100 .
[0005] A further problem is that on site cladding construction makes quality control difficult, can cause damage to the waterproofing system, and is subject to the vagaries of inclement weather during construction leading to time delay. In addition, mixing, handling and/or applying concrete slurry on site can be messy and laborious.
[0006] Still further, in the event that maintenance is required to the underlying roof deck 102 , waterproofing membrane 110 and/or components of the built-up waterproofing system 104 , 118 , 120 , 122 , the protective screed 122 and some or all underlying layers need to be destructively removed such as by being cut away, effectively destroying the construction 100 . The entire process of building up the waterproofing system must then be repeated to re-establish a waterproof cladding.
[0007] Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is solely for the purpose of providing a context for the present invention. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention as it existed before the priority date of each claim of this application.
[0008] Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 illustrates a typical roof cladding construction;
[0010] FIG. 2 is a perspective view of a formwork for cement casting for a composite cement panel according to one embodiment of the present invention;
[0011] FIG. 3 is a perspective view of a foam board placed in the formwork of FIG. 2 for fabricating a composite cement panel according to one embodiment of the present invention.
[0012] FIG. 4 is a flowchart showing a process for fabricating a cement panel using the formwork of FIG. 2 .
[0013] FIG. 5A is a top view of a composite cement panel according to one embodiment of the present invention.
[0014] FIG. 5B is a bottom view of FIG. 5A .
[0015] FIG. 6A is a front view of FIG. 5A .
[0016] FIG. 6B is a cross sectional side view of FIG. 5A .
[0017] FIG. 6C is a partially enlarges view of FIG. 6B .
[0018] FIG. 7A is a perspective bottom view of FIG. 5A .
[0019] FIG. 7B is a partially cross sectional perspective view of FIG. 5A .
DETAILED DESCRIPTION OF THE INVENTION
[0020] FIG. 2 shows a formwork 2 , made of metal for example, for casting a composite cement panel 800 shown in FIG. 7A . Formwork 2 has an array of recesses 3 formed on the base surface 4 . Recesses 3 are positioned spaced apart from each other across the base surface 4 of the formwork 2 . Guide abutments 6 are provided on two adjacent inner surfaces 214 , 215 of the metal formwork 2 . Formwork 2 further includes pins 8 positioned on the bottom surface 4 . Pins 8 extend upwardly from the base surface 4 of formwork 2 . Formwork 2 ends with an upturn skirting 7 along the peripheral edge, allowing ease of handling the formwork 2 during casting or transportation of the cement panel 800 .
[0021] FIG. 3 illustrates a light-weight core material board, such as a foam board 200 , placed in formwork 2 before the process of cement casting of the composite cement panel 800 . Foam board 200 has through holes 202 formed thereon by, for example, drilling, stamping, cutting, punching or pre-made integratedly during a molding process forming the foam board. Through holes 202 are configured such that, when foam board 200 is placed in formwork 2 , each through hole faces one recess of formwork 2 . When placed in formwork 2 , foam board 200 sits on pins 8 , leaving a gap between foam board 2 and bottom surface 4 of formwork 2 .
[0022] FIG. 4 is a flowchart of a process 300 for fabricating a cement panel using the formwork 2 shown in FIG. 2 . At step 302 , foam board 200 having through holes 2 formed there on, is placed in the formwork 2 , with two adjacent sides of the form board acting against a respective guide abutment 6 . This way, there is remained a side gap between the periphery of foam board and inner surfaces 214 and 215 of formwork 2 .
[0023] At step 312 a pre-mixed self-levelling high strength cement grout, with or without concrete hardener or chemical additive, is prepared. At step 306 , the cement grout is poured onto foam board 200 and into formwork 2 . During this step, cement grout will fill up the round recesses 3 in the formwork 2 , the gap between the foam board and the bottom surface 4 of formwork 2 , the gap between the periphery of foam board 200 and inner surfaces 214 , 215 , 216 and 217 of formwork 2 , and the holes 202 of the foam board 200 . At step 308 , the cement grout fills formwork fully, and is trowelled and finished. At step 310 the cement grout is left to dry and harden, hence to form a cement casing 502 encapsulating foam board 200 , and form the composite cement panel. At step 314 the formed cement panel is removed from the formwork 2 .
[0024] Depending the building roof conditions and the finishing requirements, the composite cement panel may be fabricated with a suitable finishing layer on its top surface. For example, at an optional pre-dry finishing step 318 , pebbles may be pours onto the top surface of the wet composite cement panel. The pebbles are then attached onto the top surface of the panel, and dried together with the panel. Alternatively, color cement powders may be supplied onto the top surface of the wet composite cement panel and dried together, so as to form a colored finishing layer. Imprints with predetermined patterns may also be formed, by molding or pressing the patterns on the top surface of the composite cement panel. In a further optional after-dry step 320 , as an alternative of step 318 , the dried composite cement panel may be covered by tiles, wood panels or natural/artificial stones and/or a layer of heat-insulating or waterproof coating.
[0025] FIGS. 5A , 5 B, 6 A, 6 B, 6 C, 7 A and 7 B illustrate a composite cement panel 800 produced after step 314 of process 300 (shown in FIG. 4 ). With reference to FIG. 6A and FIG. 6B , it can be seen that the foam board 200 is encapsulated in the cement casing 502 . Also, it can be seen from FIG. 6C that the top portion 204 and bottom portion 206 of the cement casing is bound by portions of cement 520 a surrounding the foam board 200 as well as the portions filling the holes 202 of the foam board 200 . Portions of cement casing 502 fills in the holes 202 of foam board 200 , forming columns 570 . These columns 570 increase the strength and rigidity of the cement panel 800 , and serve to distribute applied weight, such as foot traffic, to reduce the likelihood of foam board 200 being crushed. Portions of the cement casing filling in the round recess 3 of formwork 2 form legs 220 at the bottom side 250 of the composite cement panel 800 . Additionally, the foam board 200 is chemically bonded to the cement casing 502 by additives in the cement grout.
[0026] With reference to FIGS. 7A and 7B , legs 220 extend downwardly from the bottom surface 250 of the cement panel 800 . When leveled on top the roof top surface of a building, legs 220 rests on the roof top surface, providing a network of multi-directional free-flow paths between the spaces of the legs 220 for draining water along the underside of the cement panel 800 . Provision of legs 220 of cylinder shape and multi-directional flow paths reduces trapping of residual water in the cement panel 800 , and at the same time allows the water to flow in multiple-directions on the roof top surface level. Thus, better drainage of water can be achieved even in heavy rainfall. By encapsulating the foam board in the cement casing, water or moisture is prevented from penetrating into the panel and wet the foam board, hence the likelihood of the foam board deformation or damage caused by water or moisture content is avoided.
[0027] The size and thicknesses of foam boards 200 are kept in appropriate ratio to the size and thickness of the finished cement panel 800 to achieve a satisfactory effect of thermal insulating. In one embodiment, the dimensions of foam board 200 are 18 mm thick by 480 mm width by 480 mm length. Specifications of the one exemplary polystyrene foam board 200 are listed in Table 1 below.
[0000]
TABLE 1
Specification of foam board
Property
Test Method
Unit(s)
Typical Value(s)
Density
kg/m 3
40~50
Thermal
ASTM C518:
W/m ° K
0.02207
Conductivity
1991
kcal/mm ° K
0.01897
10% Compressive
ASTM D 1621:
N/mm 2
0.30
Strength (Average)
2000
Flammability
ASTM C635: 91
cm/min
10.0
Classification
(Average burning
rate)
Water Absorption
ASTM C272:
%
0.01
(Average)
2001
Temperature of Hot
° C.
40.77
Surface
Temperature of
° C.
19.95
Cold Surface
Mean Temperature
° C.
30.36
[0028] The composition of an exemplary pre-mixed, self-leveling, high strength cement grout is listed in Table 2 below.
[0000] TABLE 2 Composition of cement grout Name CAS Proportion Portland Cement 65997-15-1 10-60% Sand (Crystalline Quartz) 14808-60-7 10-60% Flow Aid, Plasticiser 0-1% Concrete Strengthener Additive 250 ml
The specification of an exemplary concrete strengthener is listed in Table 3 below.
[0000]
TABLE 3
specification of the concrete strengthener
Property
Unit
Typical Value
Solid Content
%
>40
Density
kg/m 3
1.16 ± 0.04
Crack Filing
mm
0.1-2
Depth of Absorption (for
mm
1-8
Grade 20 Concrete)
Flash Point Waterborne
Not flammable
Drying Time
hours
1-3
Weather Condition
° C.
10-50
UV Resistance
Stable
[0029] It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the spirit or scope of the invention as broadly described. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.
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This invention relates to a composite panel for a rooftop surface having a core material board having a top surface and a bottom surface with a plurality of openings through said core material board extending from said top surface to said bottom surface; a rigid outer shell of solid material that encapsulates said core material board; a plurality of supports of said solid material wherein each of said plurality of supports extends through one of said plurality of openings in said core material board; and a plurality of legs on a portion of said rigid outer shell covering said bottom surface of core board material.
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ORIGIN OF THE INVENTION
The invention described herein was made by employees of the United States Government and may be manufactured and used by or for the Government for governmental purposes without the payment of any royalties thereon or therefor.
FIELD OF THE INVENTION
This invention relates to a machine or apparatus. Specifically, this invention pertains to an apparatus for testing the sealing characteristics of O-ring gaskets under a variety of conditions.
BACKGROUND INFORMATION
Prior to the present invention, typical test fixtures for testing the sealing characteristics of O-ring gaskets used as bore seals were of two types. First, there was the totally static fixture. This fixture, as its name implies, checked O-ring performance under a totally static configuration, i.e., neither surface in contact with the O-ring was allowed to move. The second type was a partially dynamic test fixture. Under this configuration, one of the surfaces in contact with the O-ring was allowed to rotate with respect to the O-ring during the test. In addition, axial movement across the face of the O-ring could also be simulated with the second test fixture. However, neither fixture could check the response of an O-ring gasket where there was radial movement of the sealing surface away from the O-ring, i.e., where the space or gap filled by the O-ring became enlarged.
The present invention was first discussed in NASA test reports covering various results of testing performed on the invention. One report was dated January 1987 and the other one was dated Dec. 22, 1987. Both reports were authored by James E. Turner, a coinventor of the present invention, and were restricted to NASA personnel and NASA contractors only. The invention was first disclosed to the public at a conference in a paper entitled "Evaluation of the Sealing Ability of Various O-ring Materials for the Space Shuttle Redesigned Solid Rocket Motor," which was presented on June 7, 1988.
SUMMARY OF THE INVENTION
The present invention has the ability to test the sealing characteristics of O-ring gaskets under a variety of dynamic loading conditions. Where an O-ring is expected to perform a sealing function against a high-pressure fluid, the present invention allows the O-ring to be checked under various combinations of parameters. These parameters include (1) temperature, (2) pressure, (3) rate of pressurization, (4) magnitude of radial gap-opening, (5) rate of radial gap-opening, (6) pressurization as a function of gap-opening, and (7) position of the O-ring gasket in the O-ring gland prior to pressurization. The term "gap-opening" refers to the condition where the space filled by the O-ring enlarges due to some external force. Thus, where the installed O-ring has to react to some gap-opening in order to maintain an effective seal, the present invention has the capability to simulate both the maximum gap-opening expected to occur in practice and the rate at which the gap opens.
An object of the present invention is to check the sealing ability of an O-ring gasket as the sealing surface moves away from the O-ring.
Another object of this invention is to check the sealing ability of an O-ring gasket both as the sealing surface moves away from the O-ring and as the sealing surface slides in an axial direction across the face of the O-ring.
BRIEF DESCRIPTION OF THE DRAWINGS
Further details of the present invention are explained below with the help of the attached drawings in which:
FIGS. 1A and 1B represent a sectional view and a top view, respectively, of the housing belonging to the present invention.
FIGS. 2A and 2B represent a sectional view and a top view, respectively, of the conical piston belonging to the present invention.
FIGS. 3A and 3B represent a sectional view and a top view, respectively, of the cap plate belonging to the present invention.
FIG. 4 shows a preferred embodiment of the completely assembled O-ring testing apparatus.
FIG. 5 shows an alternative embodiment, completely assembled, of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A preferred embodiment of the present invention comprises a housing, a conical piston, a pressurizing means, and a means for controlling movement of the conical piston relative to the housing.
FIGS. 1A and 1B show a housing (10) of the present invention having a conical bore (12). The conical bore (12) tapers or inclines from a line parallel to a longitudinal axis (14) of the conical bore (12) at a predetermined angle (16). The angle is computed from the ratio of the desired magnitude of radial gap-opening to the desired magnitude of axial displacement. The housing also contains a variety of ports (18) which extend between an exterior surface (19) of the housing (10) and the conical bore (12). These ports (18) are located to facilitate pressurization where appropriate and to monitor the amount and rate of fluid leakage past the O-ring seals.
FIGS. 2A and 2B show a conical piston (20) having a longitudinal axis (22). The conical piston (20) tapers or inclines from the longitudinal axis (22) at the same angle (16) as that of the conical bore (12) in the housing (10). The purpose of this angle is, here again, to produce a given amount of radial gap-opening for a given amount of axial displacement along the O-ring. The conical piston (20) also has a first gland (24) in which an O-ring gasket is placed for testing. A second gland (26) may be provided for a second O-ring gasket in order to contain or monitor secondary leakage subsequent to any leakage past the O-ring in the first gland (24) A third gland (28) may be provided to contain or monitor the amount of any leakage past the O-ring in the second gland (26). Each gland has a high pressure or upstream side and a low pressure or downstream side. A passageway (29) can be provided in the piston (20) through which a fluid at the desired temperature may be circulated to control the testing temperature.
FIGS. 3A and 3B show a cap plate (30). The cap plate (30) functions as another part of the housing (10) and is used to enclose or restrain the conical piston (20) during testing. The cap plate (30) has an opening (32) through which the movement of the piston (20) is controlled. The cap plate may further have another passageway (34) to match the passageway (29) in the piston (20) to aid in temperature control.
FIG. 4 shows the housing (10), the conical piston (20), and the cap plate (30) of the present invention completely assembled. The piston (20) is slidably mounted within the housing (10) such that the piston (20) is coaxial with the conical bore (12) of the housing (10). With the piston (20) in the housing (10), a chamber (41) is formed between the housing (10) and the piston (20). During testing operations, the chamber (41) is pressurized through a pressurization port (42) which extends between the chamber (41) and the exterior surface (19) of the housing (10). The ports (18) are usually arranged in the housing (10) so there is access to the spaces between the housing (10) and the piston (20) and between adjacent O-rings. The ports (18 and 42) are used for pressurization and to monitor any leakage which may occur. Leakage past the O-ring gasket may be detected with the use of a pressure transducer (46).
FIG. 4 also shows a hydraulic actuator (43) attached to piston (20) as a means for controlling piston movement. The hydraulic actuator (43) may be used to control both the rate and magnitude of radial gap movement. To more precisely control the initial gap-opening and the final gap-opening, shims (44) may be provided between the housing (10) and the piston (20) or between the housing (10) and the cap plate (30) as shown in FIG. 4.
FIG. 4 further shows a displacement transducer (45) installed between the piston (20) and the housing (10). This transducer (45) is used to monitor the rate and amount of coaxial movement of the piston (20) relative to the housing (10). The housing (10) may be provided with a heating mechanism (not shown) to heat the O-rings to the desired temperature. An example of a heating mechanism would be to wrap the housing (10) with electrical heating strips (47). Cooling of the O-ring gaskets may be accomplished by passing a coolant such as liquid nitrogen through the passageways (FIG. 2, 29 and FIG. 3, 34) in the piston (20) and cap plate (30). Alternatively, cooling of the O-rings may be obtained by refrigerating the testing apparatus.
FIG. 5 shows an alternative embodiment which may be better suited for testing larger diameter O-rings. This embodiment is basically the same as that shown in FIG. 4 except the housing is modified. Here, the housing (10) has an opening (52) on the pressurization end (54) which is sealed with another O-ring gasket (56).
Still another embodiment (not shown) is where the housing and conical piston in the vicinity of the first gland can be separated from and reattached to the remainder of the housing and conical piston, respectively. Such a configuration has the advantage of allowing long term storage of the O-ring gasket under compression prior to testing while allowing continued use of the other parts. Thus, minimal duplication of the testing apparatus is attained where multiple tests are to be run which require long term compression of the O-ring prior to testing.
The procedure for using the present invention is straight forward. First, the O-ring to be tested is placed in the first O-ring gland. Other O-rings are also placed on the remaining glands where necessary or desired as part of the first step. If desired, the O-rings may first be coated with a lubricant prior to placing them in the gland. Second, shims may be selected to provide predetermined initial and final positions of the piston relative to the housing. Third, the piston and the shims, if used, are secured within the housing by attaching the cap plate to the housing. Fourth, any desired instrumentation is connected to the test fixture. Finally, after bringing the O-rings to the desired temperature by either heating or cooling the apparatus, the chamber is pressurized at a selected rate to the desired maximum pressure. The rate of pressurization may also be coordinated with the rate of radial gap-opening. During pressurization, the performance of the O-ring gasket can be observed and recorded.
If it is desired to properly center and seat the O-ring in the gland prior to checking its sealing characteristics, the O-ring can be pressurized slightly from both sides prior to applying the test pressure.
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An apparatus for testing O-ring gaskets under a variety of temperature, pressure, and dynamic loading conditions. Specifically, this apparatus has the ability to simulate a dynamic loading condition where the sealing surface in contact with the O-ring moves both away from and axially along the face of the O-ring.
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TECHNICAL FIELD
[0001] This invention relates to automated container code recognition for use on transfer container cranes providing container handling in cargo container storage yards.
BACKGROUND ART
[0002] In the marine shipping industry, the expected annual container traffic growth is from 4.7% to 7.6%. Container terminals are faced with the challenge of maintaining the inventory control for these escalating numbers of containers. The input, ouput and storage of containers at these terminals must provide an efficiency level that is at least consistent with, or exceeds, past performance.
[0003] Present and future growth levels have compelled terminal management companies to look for new systems to bring about more efficient resource control and, as a consequence, provide a more profitable operation.
[0004] Shipping companies wish to reduce the time a ship spends at port in order to increase the productivity of each vessel. Increasing the productivity of berthing operations allows ships to be loaded and unloaded faster, effectively reducing the time spent at port.
[0005] What is needed by both terminal management and shipping companies is a more accurate, real time accounting of incoming, outgoing and existing container inventory. A more efficient container inventory management system is needed to minimize the time spent at a port or rail yard loading and unloading containers.
[0006] [0006]FIG. 1 illustrates a typical berthing process, involving quay container cranes 2200 , transports between quay container cranes 2200 and storage yards, and storage yard containers manipulated by transfer container cranes 2100 , as found in the prior art.
[0007] The berthing operations involve the transport of containers between container ships and the storage yard. Currently, quay container cranes 2200 access the containers from above ships 220 and move them to and from transportation units 210 , such as trucks, each with a chassis, or Automatically Guided Vehicles (AGV's). The vehicles deliver the containers to storage yards 200 where other vehicles transfer the containers to stacks. The berthing process involves three operations: (1) quay container crane 2200 handling, (2) quay container crane 2200 to storage area 200 transport, and (3) storage area 200 manipulation often by one or more transfer container cranes 2100 as illustrated in FIG. 1.
[0008] Generally, there are two kinds of storage yards 200 , wheeled storage yards 200 and stack (or ground) storage yards 200 . For a wheeled storage yard 200 , each container is on a chassis and there is only one container on a chassis. For a stack (or ground) storage yard 200 , containers are stacked up to 5 levels high.
[0009] The quay container crane 2100 and transport vehicle 210 operations are highly interdependent. A delay in one operation causes the other to pause, reducing the overall productivity of the berthing process. If there are mistakes in these operations, then the overall berthing process is seriously delayed.
[0010] What is needed is a method for reducing errors and supporting efficient operation of the berthing process.
[0011] [0011]FIGS. 2A and 2B illustrate typical container codes and their representation on the side of a container as found in the prior art.
[0012] Each cargo container 100 is assigned a unique identification number 110 displayed on the sides and roof of the container. This identification number is represented in the form of a painted code and ID tag. Numerous government agencies and ship regulators require container codes on all containers. As a result, the painted container code representations of numerals and letters are used universally and internationally, as shown in FIGS. 2A and 2B.
[0013] A magnetic tag is another prior art method assigning an identification number to a container. However, the magnetic tag method suffers from several problems. The magnetic tag method is not an international standard. Magnetic tags for containers are only installed by individual shipping line owners at their discretion. Not all container transporters support magnetic tags for their containers.
[0014] Additionally, a magnetic tag must pass in close proximity to a magnetometer in order for the magnetic tag to be read. The container passing the magnetometer can be outbound and inbound. Moreover, the magnetically tagged container can be moved anywhere. Magnetic tag reading provides no information about the container's physical location.
[0015] Another prior art alternative can identify containers from a distance. It is a technically more sophisticated and expensive system requiring a transponder tag attached to each container. The transponder tags can be programmed to show different kinds of information in the form of a coded signal when interrogated by a radio frequency transceiver. Such systems are expensive, delicate, and easily damaged.
[0016] Cargo containers are the individual property of the different shipping lines. When used by a non-owner shipping line, a container rental fee is paid to the owner. At the present time, the shipping companies only know the size of each container and whether it is dry or refrigerated.
[0017] A cargo container can become lost for several reasons. Inadvertently, a container is misplaced in a different location (yard address). Sometimes a container crane operator leaves a container at the wrong address, causing the container to be lost. A computer tracking the containers parked in a container terminal storage area will have an error in the container's tracking data. As a result, the lost container is effectively invisible to the existing container terminal management system (CTMS). While this is usually discovered eventually, the container is inevitably lost for a certain time.
[0018] A cargo container can become lost when the container ID number is incorrectly input into the CTMS. A cargo container can become lost when the container ID number is unreadable due to dirt, scratches, being covered, or an incorrect label on the container.
[0019] Any of these errors can result in disruptions of the inventory database. In addition, these errors become particularly serious when one attempts to place a second container into a supposedly vacant location only to find the location is already occupied, which further results in time consuming interruptions. What is needed is an efficient way to track all the containers and update an inventory database. What is further needed is an efficient way to track all containers in both wheeled storage yards and stack storage yards.
[0020] It can take a week in a major container storage yard to find a lost container. This can delay a ship's departure and/or the container's delivery to its destination. Either and/or both delays cost the shipping companies money.
[0021] Today, there is a large turnover of cargo containers in the seaports. This cargo turnover makes it necessary to regularly update the CTMS database. What is needed is an automated method of updating the CTMS database in real-time that will work efficiently even during the rush hours.
[0022] Today, a known disclosure teaching automatic reading of container ID tags on container cranes, is found in U.S. Pat. No. 6,356,802 entitled “Method and apparatus for location cargo containers”, by Takehara (one of the inventors of this application) and Ng. The '802 patent is assigned to the same assignee as this application, Paceco Corp. The '802 patent discloses “The system can be installed on cranes to identify containers at wharfside and on straddle carrier cranes for identifying containers in single or multiple stack container storage. The system can be installed on cranes to identify containers mounted on rail cars in rail terminals . . . ” (Lines 50-55, Column 4)
[0023] “The machine reader, its associated apparatus, and the LDU, are carried onboard a transporter such as a cart which runs on tracks or can be steerable. The cart can either be operator driven or remotely controlled. The apparatus could be mounted onboard the storage yard patrol truck. . . . The machine reader can be alternatively aimed by the transporter, remotely controlled, or handheld by an operator.” (lines 40-48, Column 6) Note that “LDU” is disclosed as “location determining unit” in line 1 of Column 6.
[0024] “. . . the present invention contemplates wireless transmission of the data from the machine reader/transporter to the central terminal where the CTMS is located for real time data updating. This can be accomplished by a wireless modem, or a communication unit, which transmits the container's ID number and its current location back to the stationary central computer which hosts the CTMS program and also contains the inventory database.” (line 65 Column 6-line 6 Column 7) CTMS refers to container terminal management system (line 12 Column 3).
[0025] “The identification means is scanned from a distance by a machine such as an optical character recognition (OCR) unit to interrogate the ID tag and identify the container. It is an important characteristic of the invention that an operator of the system is able to remotely interrogate an ID tag of a cargo container . . . without the necessity of physically approaching and contacting the container or even coming in close proximity thereto.” (lines 3-10 Column 5)
[0026] While of value, the '802 patent fails to disclose or teach at least the following:
[0027] 1. How to track containers in stack storage yards, which may pile containers as many as five levels high.
[0028] 2. There are advantages to monitoring cargo container operations by a container crane either through sensing the control system of the container crane, or through the use of sensors external to the container crane's control system.
[0029] 3. Real-world optical character recognition systems occasionally make mistakes or are unable to recognize the characters, often requiring reliability estimates of the recognized container ID.
[0030] 4. There is a practical requirement for an automatic container code reading machine to send a version of the image(s) captured by its video imaging device(s) to a remote operator. This again stems from the real-world limitations of optical character recognition systems at recognizing the characters.
[0031] 5. There is a practical requirement for the machine to minimize bandwidth in sending the video image(s) across at least a wireless physical transport layer.
[0032] 6. There are significant advantages in many real-world situations for the machine to have multiple video imaging devices placed apart from at least each other, rigidly affixed to the container crane. Such advantages include the ability to withstand the severe mechanical vibrations container cranes experience, while providing container code observations from various locations about and around the container crane, which include providing the length of the cargo container.
[0033] 7. There are further advantages to positioning multiple, independently controlled lighting systems to improve the imaging quality of the multiple video imaging devices.
[0034] To summarize, what is needed by both terminal management and shipping companies is a more accurate, real time accounting of incoming, outgoing and existing container inventory as the container cranes act upon and around the containers, particularly with regards to stack storage yards.
[0035] What is needed is a method of reducing errors and supporting efficient operation in the berthing process through the automated monitoring of cargo container loading and unloading.
[0036] What is needed is an automatic container code reading machine sending a version of the image(s) captured by its video imaging device(s) to the remote operator. The bandwidth needs to be minimized in sending video image(s) across at least a wireless physical transport layer. The machine needs, in many real-world situations, to include multiple video imaging devices placed apart from each other and rigidly affixed to the container crane. Multiple, independently controlled lighting systems may further be needed, positioned to improve the imaging quality of the multiple video imaging devices.
[0037] Note that the problems discussed herein also relate to rail yard container inventories as well.
SUMMARY OF THE INVENTION
[0038] The invention solves at least all the problems discussed above regarding the prior art.
[0039] The invention provides a method and system supporting container code recognition from a transfer container crane 2100 communicating with a container inventory management system. An optical characteristic recognition system preferably tracks container movement within a container stacking yard, which may be either a wheeled storage yard or a stack storage yard.
[0040] The invention can read the standard universal identification (ID) tags internationally used on containers. Container ID tags will be referred to hereafter as container codes. Container inventory management systems incorporating this invention can be integrated into existing container terminal management systems (CTMS). Since each cargo container carries a standard container code, the invention can be utilized for tracking of all containers with respect to their history, damage, current location, and use.
[0041] The invention supports operators remotely interrogating a container code without the need to physically approach the container. The optical characteristic system further provides at least one video image, which is compressed and may be sent via a wireless physical transport to the container inventory management system. The video image compression effectively minimizes the bandwidth required to send video images.
[0042] The invention preferably includes multiple video imaging devices mechanically coupled at distinct locations about the transfer container crane 2100 . The invention further preferably includes multiple, independently controlled lighting sources. At least two of the multiple lighting sources are further, preferably, mechanically coupled apart from each other on transfer container crane 2100 to provide length estimates of a cargo container.
[0043] The invention reduces container inventory errors and increases the overall terminal efficiency.
[0044] Optical characteristic recognition systems are sometimes referred to as container code readers. Optical characteristic recognition systems may further interrogate the contents of a container.
[0045] These and other advantages of the invention will become apparent upon reading the following detailed descriptions and studying the various figures of the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0046] [0046]FIG. 1 illustrates a typical berthing process involving quay container cranes 2200 , transports between quay container cranes 2200 and storage yards, and storage yard containers manipulated by transfer container cranes 2100 , as found in the prior art;
[0047] [0047]FIGS. 2A and 2B illustrate typical container codes and their representation on the side of a container as found in the prior art;
[0048] [0048]FIG. 3 illustrates a marine shipping yard 20 in accord with the invention;
[0049] [0049]FIG. 4A illustrates a simplified block diagram of the container inventory management system 1000 of FIG. 3 using the optical characteristic recognition systems;
[0050] [0050]FIG. 4B illustrates a system block diagram of the means for operating 3300 optical characteristic system 3000 implementing the inventive method for automated optical container code recognition with positional identification from a transfer container crane 2100 of FIGS. 3 and 4A;
[0051] [0051]FIG. 5 illustrates a simplified block diagram of an optical characteristic system 3000 providing container code recognition from transfer container crane 2100 , of a container 100 identified by a container code 110 , to container inventory management system 1000 ;
[0052] [0052]FIG. 6A illustrates a method of operating optical characteristic system 3000 of FIG. 5 as program system 3300 of FIG. 5;
[0053] [0053]FIG. 6B illustrates certain embodiments of the optical characteristic 3250 from FIG. 5 of the container code 110 of FIGS. 2 A-B and 5 .
[0054] [0054]FIG. 6C illustrates positional identification 3260 of FIG. 5 for container 100 .
[0055] [0055]FIG. 7 illustrates a detail flowchart of operation 3332 of FIG. 6A for generating the optical characteristic of the container code;
[0056] [0056]FIG. 8A illustrates a detail flowchart of operation 3342 of FIG. 6A for generating the positional identification of the container;
[0057] [0057]FIG. 8B illustrates a detail flowchart of operation 3462 of FIG. 8A for generating the storage-location designation;
[0058] [0058]FIG. 8C illustrates a preferred detail flowchart of operation 3472 of FIG. 8A for generating the terminal location for the transfer container crane 2100 ;
[0059] [0059]FIG. 9A illustrates a detail flowchart of operation 3362 of FIG. 7 for acquiring the container code image;
[0060] [0060]FIG. 9B illustrates a detail flowchart of program system 3300 of FIG. 5 implementing the method of operating the optical characteristic recognition system;
[0061] [0061]FIG. 9C illustrates a detail flowchart of operation 3392 of FIG. 7 for processing the first container code image;
[0062] [0062]FIG. 10 illustrates a detail flowchart of operation 3352 of FIG. 6A for sending the optical characteristic and the positional identification;
[0063] FIGS. 11 A- 11 C illustrate various detail flowcharts of operation 3452 of FIG. 8A for generating the loading-operation;
[0064] [0064]FIG. 12 illustrates optical characteristic recognition system 3000 video imaging devices mechanically coupled to transfer container crane 2100 as found in FIGS. 3 to 5 ;
[0065] [0065]FIG. 13 illustrates a preferred embodiment of at least part of the mechanical housing of an optical characteristic recoginition system; and
[0066] [0066]FIG. 14 illustrates a simplified block diagram of a preferred optical recognition system 3000 .
DETAILED DESCRIPTION OF THE INVENTION
[0067] The invention provides a method and system supporting container code recognition of a container, from a transfer container crane 2100 as shown in FIG. 1, to manage at least a container inventory. The invention automatically and efficiently tracks the location of the container in a container storage area, automatically updating at least the container inventory database.
[0068] The invention allows a container code reader to find any container in a storage area including containers carrying specialized tag identifiers. The invention supports remotely interrogating a container for identification.
[0069] [0069]FIG. 3 illustrates a marine shipping yard 20 in accord with the invention.
[0070] System 1000 uses container code recognition of a container 100 , identified by a container code 110 as shown in FIGS. 2A and 2B, from transfer container crane 2100 shown in FIG. 1 to manage at least a container inventory. The invention automatically and efficiently tracks the location of the container in a container storage area 200 , automatically updating at least a container inventory database.
[0071] As used herein, a container crane is at least one of the following: a quay side container crane 2200 , a transfer container crane 2100 , as well as rubber tire gantry container cranes and rail gantry container cranes. Quay container cranes 2200 are illustrated in FIGS. 1, 3, and 4 A. Transfer container cranes 2100 are illustrated in FIGS. 1, 3, 4 A to 5 , and 12 . It should be noted that transfer container cranes 2100 are predominantly rubber tire gantry container cranes, while quay container cranes 2200 are predominantly rail gantry container cranes.
[0072] [0072]FIG. 4A illustrates a simplified block diagram of the container inventory management system 1000 of FIG. 3 using the optical characteristic recognition systems.
[0073] The method of operating the system 1000 will be discussed in terms of computer 1010 , controlled by a program system 1200 , including program steps residing in a memory 1020 accessibly coupled 1022 to computer 1010 .
[0074] The system 1000 further includes computer 1010 communicatively coupled 1002 to optical characteristic system 3000 , which is mechanically coupled to transfer container crane 2100 .
[0075] Computer 1010 is also communicatively coupled to optical characteristic system 3000 , mechanically coupled to quay container crane 2200 . The communicative coupling of computer 1010 and optical characteristic system 3000 may be at least partially provided by network 1004 through network interface 1030 , which in turn communicates 1032 with computer 1010 .
[0076] Note that in many embodiments of the invention, the communicative coupling of various optical characteristic systems 3000 may employ a uniform coupling mechanism, which in many circumstances may preferably be a network.
[0077] Network 1004 may employ at least one member of a physical transport collection in communicating with an optical characteristic system 3000 in quay container crane 2200 . The physical transport collection includes at least one wireline physical transport layer and preferably at least one wireless physical transport layer.
[0078] Computer 1010 is communicatively coupled 1102 with database 1100 . Note that database 1100 may be included in at least one member of a container inventory management collection comprising a marine shipping inventory management system and a rail yard inventory management system.
[0079] Note that the system includes received optical characteristic 1100 and received positional identification 1150 . In certain systems, it is preferred that both received optical characteristic 1100 and received positional identification 1150 reside in memory 1020 . However, the system may include one or both of 1100 and 1150 residing somewhere other than memory 1020 , including but not limited to them residing in network interface 1030 .
[0080] Program system 1200 of FIG. 4A manages at least a container inventory using container code recognition of a container identified by a container code. The container code recognition is performed on the container crane, which may be either a transfer container crane 2100 or a quay container crane 2200 seen in FIG. 3.
[0081] The container inventory management includes the following: Receiving an optical characteristic of the container code and a positional identification of the container to create a received optical characteristic 1100 and a received positional identification 1150 . Updating a database with the received container code optical characteristic and the received container positional identification.
[0082] As used herein, a computer will be considered to include at least one of the following: an instruction processor, an inferential processor, a finite state machine, and a memory.
[0083] An instruction processor will include at least one of the following. A Single Instruction Single Datapath (SISD) processor, a Single Instruction Multiple Datapath (SIMD) processor, a Multiple Instruction Single Datapath (MISD) processor, a Multiple Instruction Multiple Datapath (MIMD) processor, a Complex Instruction Set Computer (CISC), a Reduced Instruction Set Computer (RISC) and a Very Long Instruction Word (VLIW) computer.
[0084] An inferential processor will include at least one of the following: a rule-based inferential processor, a constraint-based inferential processor, and a fuzzy logic engine.
[0085] A finite state machine will include at least one of the following: at least part of a programmable logic device, at least part of an application specific integrated circuit. A programmable logic device will refer to at least one member of the following: a Field Programmable Gate Array(FPGA), a Programmable Logic Device (PLD), a Complex Programmable Logic Device (CPLD).
[0086] As used herein, memory 1020 includes at least one instance of a volatile memory and/or at least one instance of a non-volatile memory. Non-volatile memory includes at least one of the following: a writeable non-volatile memory and a Read Only Memory (ROM). Writeable non-volatile memory includes at least one member of the following: an electro-magnetically interfaced non-volatile memory and an optically interfaced non-volatile memory.
[0087] Please refer to FIG. 6B for a discussion of the optical characteristic of the container code.
[0088] Receiving the optical characteristic and the positional identification of the container may include the following. Determining a reliability measure of the estimated container code. Examining the container code image to create a second estimated container code, whenever the reliability measure indicates doubt.
[0089] Examining the container code image may include at least one of the following. Requesting a modified version of the container code image to create a modified container code image request. Receiving a modified container code image based upon the modified container code image request.
[0090] Also note that the modified container code request may include at least one of the following: a zoom-in request; a zoom-out request; a tilt request; a filter request. The filter request may includes at least one of the following: an apply first filter request, an apply second filter request; and an align the first filter to the second filter request.
[0091] The positional identification of the container as illustrated in FIG. 6C may include at least one of the following: a loading-operation designation for the container, a storage-location designation for the container, and a terminal location for the container crane.
[0092] Note that the invention includes embodiments wherein at least one of the storage-location designation and the loading-operation designation for the container, is derived, at least in part, from the terminal location for the container crane.
[0093] Receiving the optical characteristic and the positional identification may include the following. Receiving a packet from a network to create a received packet. Processing the packet to create at least part of the optical characteristic. Processing the packet to create at least part of the positional identification.
[0094] The method and system may further include generating a shipping container plan for a ship 220 shown in FIG. 3, loaded by quay container crane 2200 based upon database 1100 .
[0095] Note that the container inventory management 1000 is not limited to the following discussion, but is included to illustrate only a preferred use of container crane optical characteristic recognition systems 3000 illustrated in FIG. 4B, coupled to transfer container cranes 2100 and quay container cranes 2200 , as shown in FIG. 4A.
[0096] [0096]FIG. 4B illustrates a system block diagram of the means for operating 3300 optical characteristic system 3000 implementing the inventive method for automated optical container code recognition with positional identification from a transfer container crane 2100 of FIGS. 3 and 4A.
[0097] Optical characteristic system 3000 includes at least two video imaging devices 3100 and 3110 , each communicatively coupled 3104 and 3114 , respectively, to means 3332 for generating optical characteristic 3250 of container code based upon at least two video imaging devices 3100 and 3110 . Video imaging devices 3100 and 3110 are mechanically coupled 3102 and 3112 , respectively, to transfer container crane 2100 .
[0098] Note that optical characteristic recognition system 3000 may also be mechanically coupled 3002 to transfer container crane 2100 . Mechanical coupling 3002 may preferably include a mechanical shock absorber to improve the reliability of optical characteristic recognition system 3000 .
[0099] Note that as used herein, a video imaging device such as 3100 belongs to a collection including at least a video camera, a digital video camera, and a charged coupled array. A video imaging device 3100 may further include any of the following: a computer, a digital memory, an image processor and a flash lighting system.
[0100] Means 3342 for generating position identification 3260 of the container may include any of the following: Coupling to PLC unit 2010 on transfer container crane 2100 , coupling to quay crane relay controls 2020 , and container sensors 3270 . Container sensors 3270 may preferably include sensors to ultrasonic transponders. Coupling to PLC unit 2010 may include one or more indications of container locking, often known as twist locking signals.
[0101] Means 3342 preferably includes coupling 3232 to a GPS receiver 3230 .
[0102] Means 3352 for sending optical characteristic 3250 and positional identification 3260 to container inventory management system 1000 is communicatively coupled 1002 to container inventory management system 1000 .
[0103] Note that as used herein GPS includes any form of global positioning, including but not limited to, DGPS, (Differential Global Positioning System). Today, DGPS is the preferred global positioning form for the invention, but the invention can use any form of global positioning.
[0104] [0104]FIG. 5 illustrates a simplified block diagram of a preferred optical characteristic system 3000 providing container code recognition from a transfer container crane 2100 of a container 100 identified by a container code 110 to container inventory management system 1000 refining FIG. 4B.
[0105] Optical characteristic system 3000 includes at least one, and in FIG. 5, two video imaging devices 3100 and 3110 , each communicatively coupled 3104 and 3114 , respectively, to computer 3200 . Video imaging devices 3100 and 3110 are mechanically coupled 3102 and 3112 , respectively, to transfer container crane 2100 .
[0106] Note that optical characteristic recognition system 3000 is mechanically coupled 3002 to transfer container crane 2100 . Mechanical coupling 3002 preferably includes a mechanical shock absorber to improve the reliability of optical characteristic recognition system 3000 .
[0107] Computer 3200 accesses memory 3210 , which includes program steps of program system 3300 , which implement the method of operating 3300 the optical characteristic system 3000 . The method will be further documented in the discussion of FIGS. 6A through 11C.
[0108] The invention may incorporate a number of location determination mechanisms, preferably including a GPS receiver 3230 and communicatively coupled 3232 with computer 3200 . GPS receiver 3230 may preferably mechanically couple 3234 with transfer container crane 2100 ,
[0109] The invention is preferably communicatively coupled 1002 with container inventory management system 1000 . The invention may further preferably include a network interface 3220 with network 1004 providing a coupling from computer 3200 via 3222 - 3220 - 1004 with container inventory management system 1000 .
[0110] Network 1004 employs at least one member of a physical transport collection in communicating from the transfer container crane 2100 to container inventory management system 1000 . The physical transport collection includes at least one wireline physical transport layer and preferably at least one wireless physical transport layer.
[0111] Network 1004 preferably employs a packet based communications protocol, which may further preferably provide compatibility to the IEEE 802.11(b) communications standard.
[0112] [0112]FIG. 6A illustrates a method of operating optical characteristic system 3000 of FIG. 5 as program system 3300 of FIG. 5.
[0113] Operation 3332 performs generating an optical characteristic 3250 of container code 3610 based upon at least one of video imaging devices 3100 and 3110 shown in FIG. 5. Optical characteristics 3250 will be further discussed in FIG. 6B.
[0114] Operation 3342 performs generating a positional identification 3260 of container 3600 . Positional identification 3260 is further discussed in FIG. 6C.
[0115] Operation 3352 performs sending optical characteristic 3250 of container code 3610 and positional identification 3260 of container 3600 to container inventory management system 1000 as shown in FIGS. 4B and 5.
[0116] [0116]FIG. 6B illustrates certain embodiments of the optical characteristic 3250 from FIG. 5 of the container code 110 of FIGS. 2 A-B and 5 .
[0117] The optical characteristic 3250 of the container code 110 includes at least one member of the following: at least one container code image 4010 of a container representation 2620 of the container code 110 imaged from the transfer container crane 2100 . The optical characteristic 3250 may also include an estimated container code 4020 based upon an optical character recognition process applied to the container code image 4010 . Additionally, optical characteristic 3250 may include a first container code image 4030 , which may be further processed and/or modified to create container code image 4010 .
[0118] [0118]FIG. 6C illustrates positional identification 3260 of FIG. 5 for container 100 .
[0119] Positional identification 3260 may further include at least one of the following: a loading operation designation 4110 for container 100 , a storage-location designation 4120 for container 100 and a terminal location 4130 for transfer container crane 2100 .
[0120] Note that the invention may include one or more of the operations of FIG. 7.
[0121] [0121]FIG. 7 illustrates a detail flowchart of operation 3332 of FIG. 6A for generating the optical characteristic of the container code.
[0122] Operation 3362 performs acquiring at least one container code image of a container representation of the container code imaged from the video imaging device.
[0123] Operation 3372 performs applying an optical character recognition process to the container code image to create an estimated container code.
[0124] Operation 3382 performs acquiring a first container code image from the video imaging device of the container representation of the container code.
[0125] Operation 3392 performs processing the first container code image to create the container code image.
[0126] Operation 3402 performs compressing the first container code image to create the container code image.
[0127] The invention may also include one or more of the operations of FIG. 8A.
[0128] [0128]FIG. 8A illustrates a detail flowchart of operation 3342 of FIG. 6A for generating the positional identification of the container.
[0129] Operation 3452 performs generating a loading-operation designation for the container 100 shown in FIG. 5.
[0130] Operation 3462 performs generating a storage-location designation for the container 100 shown in FIG. 5.
[0131] Operation 3472 performs generating a terminal location for the transfer container crane 2100 shown in FIG. 5.
[0132] [0132]FIG. 8B illustrates a detail flowchart of operation 3462 of FIG. 8A for generating the storage-location designation.
[0133] Operation 3492 performs deriving the storage-location designation for the container at least in part from the terminal location for the transfer container crane 2100 shown in FIG. 5.
[0134] [0134]FIG. 8C illustrates a preferred detail flowchart of operation 3472 of FIG. 8A for generating the terminal location for transfer container crane 2100 shown in FIG. 5.
[0135] Operation 3512 performs receiving a location reading from a Global Positioning System (GPS) receiver 3230 to create at least in part the terminal location for the transfer container crane 2100 shown in FIG. 5.
[0136] The invention may include at least one of the operations of FIG. 9A.
[0137] [0137]FIG. 9A illustrates a detail flowchart of operation 3362 of FIG. 7 for acquiring the container code image.
[0138] Operation 3532 performs selecting a first of at least two of the video imaging devices mechanically coupled to the transfer container crane 2100 shown in FIG. 5.
[0139] Operation 3542 performs acquiring the container code image from the first video imaging device of the container representation of the container code 110 shown in FIG. 5.
[0140] [0140]FIG. 9B illustrates a detail flowchart of program system 3300 of FIG. 5 implementing the method of operating the optical characteristic recognition system.
[0141] Operation 3552 performs receiving a modified container code image request.
[0142] [0142]FIG. 9C illustrates a detail flowchart of operation 3392 of FIG. 7 for processing the first container code image.
[0143] Operation 3572 performs processing the first container code image based upon the modified container code image request to create the container code image.
[0144] The invention may include at least one of the operations of FIG. 10.
[0145] [0145]FIG. 10 illustrates a detail flowchart of operation 3352 of FIG. 6A for sending the optical characteristic 3250 and the positional identification 3260 shown in FIGS. 5, 6B and 6 C.
[0146] Operation 3592 performs sending a packet across a network 1004 to the container inventory management system 1000 as shown in FIGS. 4A and 5.
[0147] Operation 3602 performs writing the optical characteristic 3250 of the container code 110 and the positional identification 3260 of the container 100 to 3242 a removable non-volatile memory 3240 as shown 5 .
[0148] Operation 3612 performs creating the packet from at least part of at least one sending-data collection member.
[0149] Operation 3622 performs writing at least one sending-data collection member to a file contained in the removable non-volatile memory 3240 shown in FIG. 5.
[0150] Operation 3632 performs writing at least one sending-data collection member to a record contained in the removable non-volatile memory 3240 shown in FIG. 5.
[0151] Note that the sending-data collection includes the optical characteristic 3250 of the container code 110 and the positional identification 3260 of the container 100 as shown in FIG. 5.
[0152] The invention may include one of the operations of FIG. 11A. Note that operation 3652 is preferred.
[0153] [0153]FIG. 11A illustrates a detail flowchart of operation 3452 of FIG. 8A for generating the loading-operation.
[0154] Operation 3652 performs receiving a locking indication from a programmable logic controller 2010 within the transfer container crane 2100 as shown in FIG. 4B.
[0155] Operation 3662 performs determining the locking indication from a relay network 2020 within the transfer container crane 2100 as shown in FIG. 4B.
[0156] The invention may include one of the operations of FIG. 11B. Note that operation 3672 is preferred.
[0157] [0157]FIG. 11B illustrates a detail flowchart of operation 3452 of FIG. 8A for generating the loading-operation.
[0158] Operation 3672 performs determining a container hoist-trolley position based upon sensing a gray-coded hoist shaft in the transfer container crane 2100 .
[0159] Operation 3682 performs determining the container hoist-trolley position based upon sensing an ultrasonic transponder 3270 .
[0160] The coded hoist shaft preferably uses a gray code but the invention may use any coded hoist shaft.
[0161] Note that a hoist-trolley position as used herein will refer to a hoist position and/or a trolley position.
[0162] [0162]FIG. 11C illustrates a detail flowchart of operation 3452 of FIG. 8A for generating the loading-operation.
[0163] Operation 3692 performs generating the loading-operation designation based upon at least one member of the collection comprising the locking signal indication and the container hoist position.
[0164] [0164]FIG. 12 illustrates optical characteristic recognition system 3000 video imaging devices mechanically coupled to transfer container crane 2100 as found in FIGS. 3 to 5 .
[0165] The transfer container crane 2100 's optical characteristic recognition system 3000 tracks container 100 location and movements in the terminal's stack storage areas 200 as shown in FIG. 1.
[0166] The optical characteristic recognition system 3000 tracks containers 100 shown in FIG. 5 as they are transferred. Each container's unique ID code is optically read as it passes through transfer container crane 2100 's legs, shown in FIG. 12. The container code information is preferably processed by computer 3200 shown in FIG. 5, installed on container crane 2200 . The updated container status is sent to a container inventory management system 1000 , shown in FIGS. 3 to 5 , often located at a central office for the container facility. The computer 3200 will interface with the container inventory management system 1000 identifying whether the container is being added or substracted from the terminal's inventory listing.
[0167] Each time transfer container crane 2100 picks up a container 100 from a chassis or deposits a container onto a chassis, the container code 110 shown in FIG. 5 will preferably be read. The container identification is received by computer 3200 shown in FIG. 5.
[0168] The computer 3200 determines whether the container 100 is being added to storage or taken from storage. If it is being added to storage, position information 3260 is preferably given to computer 3200 from container crane 2100 sensors and from an on-board Differential Global Positioning System (DGPS) 3230 as shown in FIG. 5.
[0169] When the container 100 reaches its final location, this information is then sent to the container inventory management system 1000 , which updates the master inventory and location listing database 1100 as shown in FIG. 3.
[0170] If the container 100 is being removed from storage to be loaded either onto a ship or moved to another location, computer 3200 shown in FIG. 5 sends this data to container inventory management system 1000 and the container's new location is entered into the inventory database 1100 as shown in FIG. 3.
[0171] All container movements are preferably tracked and updated in real time giving terminal management essentially immediate knowledge of all containers at all times.
[0172] The container code 110 is preferably read as containers 100 are placed on or removed from a chassis. The container code 110 should be identified by the optical characteristic recognition system 3000 as shown in FIGS. 4B and 5.
[0173] [0173]FIG. 13 illustrates a preferred embodiment of at least part of the mechanical housing of an optical characteristic recoginition system 3000 of FIGS. 3 to 5 .
[0174] The mechanical housing of the optical characteristic recognition system includes at least one video imaging device, as well as preferably including flash lighting, the triggering and systems as illustrated in the block diagram of FIG. 5. As to the triggering system, it may include a laser photo and/or a infra-red photo sensor.
[0175] Other circuitry coupled with a container crane may provide additional storage location information and/or additional information regarding the container contents used by computer 3200 shown in FIG. 5.
[0176] [0176]FIG. 14 illustrates a simplified block diagram of a preferred optical recognition system 3000 as shown in FIGS. 4B and 5.
[0177] Note that container storage areas can be individually separated and not necessarily identified as repository locations located upon a predefined grid, as is often the case in container stacking areas.
[0178] The optical characteristic recognition system 3000 can be installed on quay container cranes 2200 to identify containers at wharfside, and on transfer carrier container cranes 2100 , to identify containers in single or multiple stack container storage.
[0179] Note that FIGS. 12 and 13 illustrate at least two and sometimes several video imaging devices ( 3100 - 3120 ) may be preferred in various applications of the inventive optical characteristic systems 3000 as shown in FIGS. 4B and 5.
[0180] Each video imaging device preferably has automatic focus control accommodating both the ambient light conditions and the target located at a distance.
[0181] Preferably, illumination for video imaging is provided by a flash light system. Generally, it includes strobe action to catch the image during daytime and at night in the absence of light. The trigger of the video imaging device is preferably based on at least the loading/unloading conditions on the container crane.
[0182] In certain applications, the flash light system may be controlled based upon which video imaging devices are selected.
[0183] The loading/unloading conditions on transfer container crane 2100 can preferably be obtained from the Programmable Logic Controller (PLC) 2010 on the container crane or from sensors 3270 shown in FIG. 4A checking whether there is a container to be loaded/unloaded. The sensors 3270 can be laser, infrared, or ultrasonic sensors. Today, laser sensors are more reliable and accurate, but, more expensive than the infrared, currently making infrared sensors preferable on a cost basis and laser sensors more preferable on a reliability and accuracy basis.
[0184] The video imaging device may preferably include both an optical character recognition process and an image processing unit to convert the container code images into a standard format. The standard format is preferably compatible with some version of JPEG.
[0185] Storage location for a container is provided by the invention to identify the container's repository address. A DGPS unit 3230 FIGS. 4B, 5 and 14 preferably determines the Z axis location of a transfer container crane. Signals of a PLC coupled with the transfer container crane can determine the X and Y axes. This determines the overall position of the container.
[0186] The DGPS unit 3230 shown FIGS. 4B, 5 and 14 is preferably used in applications with transfer container cranes 2100 due to the importance of their location. However, quay container cranes 2200 do not have the same crane location accuracy requirements, making the use of DGPS receivers 3230 less preferable.
[0187] In some cases, the address identifier for the repository locations in the container terminal storage areas are not adequately marked by optical character reading, radioactivity identification, or electronic/magnetic detection.
[0188] In some cases, a less sophisticated version of the invention is preferred, where the container location is operator input through a hand-held keypad.
[0189] The optical characteristic recognition system 3000 is preferably mounted on a movable container crane and able to operate in all types of weather.
[0190] The optical characteristic system 3000 may be automatically aimed by the container crane, remotely controlled, and/or hand-held by an operator to interrogate the address for the cargo containers.
[0191] The container code 110 as optical characteristic 3250 and positional identification 3260 are sent to the container inventory management system 1000 as shown in FIG. 5 to verify whether the container is deposited at the proper address.
[0192] The information may be sent by floppy disk. The data/information is downloaded onto a transportable data storage unit such as a floppy disk, and hand carried to the container inventory management computer system.
[0193] As shown in FIG. 5, the container crane's optical characteristic system 3000 generates information to send to the container inventory management system 1000 .
[0194] GPS unit 3230 as shown in FIG. 4B, and at least transfer container crane 2100 coupled PLC unit 2010 , are preferably used to generate the positional identification. Both signals are preferably sent to computer 3200 as shown in FIG. 14.
[0195] Computer 3200 shown in FIG. 14 may also be coupled with a serial communication board to interpret the signals sent to it. Computer 3200 may also be coupled with a digital signal circuit interacting with any or all of the following: switches, buzzers, and lights.
[0196] Computer 3200 preferably functions as a traffic controller, which manages the transmission of the data through the network interface or wireless modem 3220 shown in FIGS. 5 and 12, which converts and transmits the signals to the container inventory management system 1000 .
[0197] Computer 3200 preferably determines which signals are to be sent and in which order. The serial communication board preferably receives signals from the outside units such as video imaging devices 3100 and 3110 as shown in FIGS. 4B and 5, as well as GPS receiver 3230 shown in FIGS. 4B, 5 and 14 .
[0198] Computer 3200 translates them into a form that computer 1010 shown in FIG. 4A can process. The removable nonvolatile memory 3240 preferably stores the optical characteristic 3250 shown in FIGS. 4B, 5, and 6 B, and positional identification 3260 shown in FIGS. 4B, 5, and 6 C. Note that removable nonvolatile media includes, but is not limited to, floppy disks, zip disks, and optical disks.
[0199] Assume a container crane operator directs the optical characteristic system 3000 . The operator can be provided with a hand-held computer input or keypad, allowing the input of data. The operator inputs the data when he locates a target container as well as changes to other data in the container inventory management system.
[0200] The light and buzzers preferably allow the container inventory management system 1000 shown in FIGS. 3 to 5 send messages to the container crane operator as well as allow the transfer container crane 2100 equipment to communicate with the human operator.
[0201] For example, the lights and buzzers may preferably indicate a malfunction in the optical characteristic system 3000 and/or the location determination and/or completion of an operation such as informing the operator that a target container has been found.
[0202] Network interface 1030 may preferably include a stationary wireless modem unit connected 1032 to computer 1010 as shown in FIG. 4A. It allows the container crane's optical characteristic system 3000 and computer 1010 to exchange information. The modem 1030 receives the data transmitted by optical characteristic system 3000 and program system 1200 receives the new data and updates via 1102 database 1100 as shown in FIG. 4A.
[0203] Note that the coupling 1102 shown in FIG. 4A is often preferably a Local Area Network (LAN). Note that each container inventory management system 1000 may employ different LANs 1102 . Computer 1100 translates the received container code and positional identification into the reigning language of LAN 1102 . Note that multiple workstation computers may further be connected to LAN 1102 .
[0204] The invention also includes methods identifying container code and determining container locations in at least terminal storage areas. The steps can be described as follows:
[0205] (1) Provide an optical characteristic recognition system 3000 on a transfer container crane 2100 shown in FIGS. 4A to 5 and 14 to interrogate the representations of the container code 110 of a cargo container 100 ;
[0206] (2) Aim the optical characteristic recognition system 3000 at the container code representation 2620 shown in FIG. 5, generate at least one optical characteristic 3250 for the container code 110 and send the optical characteristic 3250 to the container inventory management system 1000 as shown in FIGS. 4B, 5 and 6 A;
[0207] (3) Determine the positional identification 3260 of the container 100 as shown in FIGS. 4B, 5 and 6 A;
[0208] (4) Send the positional identification 3260 from the transfer container crane 2100 to the container inventory management system 1000 as shown in FIGS. 4B, 5 and 6 A.
[0209] (5) At the container inventory management 1000 shown in FIGS. 4A to 5 , compare the information contained in the received signals with the database 1100 to verify whether the container 100 is deposited at the proper address.
[0210] Various embodiments of the invention support some or all of the following:
[0211] The optical characteristic recognition system 3000 shown in FIGS. 4A to 5 and 14 reliably performs under all real-life environmental conditions including any or all of the following: weather, traffic load and power supply variations.
[0212] The optical characteristic recognition system 3000 shown in FIGS. 4A to 5 and 14 can read the representations of a container's code 110 , determine the current location of container 100 , and then wirelessly transmit this data back to the container inventory management system 1000 shown in FIGS. 4A to 5 .
[0213] The optical characteristic recognition system 3000 shown in FIGS. 4A to 5 and 14 downloads and saves the optical characteristic and positional identification to an on-board buffer memory.
[0214] The optical characteristic recognition system 3000 shown in FIGS. 4A to 5 and 14 and/or the container inventory management system 1000 shown in FIGS. 4A to 5 warn the yard clerk if the actual location is different from that listed in the yard's container inventory database 1100 , as shown in FIG. 4A.
[0215] The optical characteristic recognition system 3000 shown in FIGS. 4A to 5 and 14 and/or the container inventory management system 1000 shown in FIGS. 4A to 5 allow the yard clerk to conveniently change the database 1100 .
[0216] The preceding embodiments have been provided by way of example and are not meant to constrain the scope of the following claims.
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A method and system providing a transfer container crane with container code recognition of a container identified by a container code to a container inventory management system is disclosed. The system and method are capable of performing these tasks without the use of non-standard container tagging.
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CROSS REFERENCES
[0001] This patent application is a continuation of U.S. Ser. No. 13/871,852 filed Apr. 26, 2013 (Ref. No. NES0305-US). Priority to this patent application is claimed and this patent application is hereby incorporated by reference in its entirety for all purposes. The subject matter of this patent application also relates to the subject matter of the following commonly assigned applications: U.S. Ser. No. 13/624,875 filed Sep. 21, 2012 (Ref. No. NES0245-US); U.S. Ser. No. 13/434,560 filed Mar. 29, 2012 (Ref. No. NES0212-US); U.S. Ser. No. 13/317,423 filed Oct. 17, 2011 (Ref. No. NES0159-US); International Application No. PCT/US12/00007 filed Jan. 3, 2012 (Ref. No. NES0190-PCT); and U.S. Ser. No. 13/269,501 filed Oct. 7, 2011 (NES0120-US). Each of the above-listed applications is hereby incorporated by reference in its entirety for all purposes.
FIELD
[0002] This patent specification relates to systems, methods, and related computer program products for the monitoring and control of energy-consuming systems or other resource-consuming systems. More particularly, this patent specification relates to user interfaces for thermostat temperature setpoint modification on smartphone or other space-limited touchscreen device.
BACKGROUND
[0003] In designing touch-screen based user interfaces for remotely controlling a network-connected programmable thermostat, it is desirable to provide a high level of user-friendliness and intuitiveness. Additionally, when using a wireless communication technology over a computer network, it is desirable to impact network traffic as little as possible. Notably, the above-stated goals of user-friendliness, intuitiveness, and low network impact are shared with many different remote control scenarios, and it is indeed recognized that some progress has been made in the art toward these goals, as reflected, for example, in U.S. Pat. No. 8,239,784, WO 2012118626, and US20080084400, each of which is incorporated by reference herein. However, it has been found that remote control of an HVAC system brings about one or more unique combinations of issues that need to be simultaneously resolved, all the while continuing to provide user-friendliness and intuitiveness. By way of example, it has been found desirable to provide a remote control user interface for a thermostat in which the actual resultant control signals are judiciously tailored to protect the HVAC equipment from unwarranted over-controlling, reduce unnecessary network traffic, and prevent the waste of energy, while at the same time providing a user interface experience in which the user perceives a high degree of control, a sense that they are “in command”, of an intuitive and delightfully easy-to-use temperature control system.
SUMMARY
[0004] When controlling HVAC equipment, it has been found that certain combinations of controls should be minimized so as to protect certain types of equipment. For example, repeated on/off commands during a short time interval can cause excessive wear, damage, and/or malfunction of certain types of HVAC equipment. According to some embodiments a user-friendly graphical user interface (GUI) is described for adjusting an immediate control set point temperature for round thermostat having circular control member surrounding display.
[0005] According to some embodiments the user experience is enhanced by allowing large-scale changes while reducing the risk of sudden unintended changes. In particular, reducing or eliminating “surprising” changes, have been found to profoundly degrade the user's interface experience. Surprising and/or sudden large changes have also been found to lead to a user perception of poor quality.
[0006] According to some embodiments, the impact on network traffic is reduced. Overly heavy traffic increases risk of data corruption and also has battery implications, since each device is woken-up for the update. Furthermore, the risk of impacting HVAC system devices due to repeated conflicting commands is also reduced. For example, certain components such as the fan are not normally protected against turning on/off quickly. However, there will still be a large inductive load cycle with fan going on/off/on/off. Additionally, according to some embodiments there is a reduced risk of excessive user interaction (e.g. over-playfulness).
[0007] According to one or more embodiments, a method is described for interactively and graphically interfacing with a user of an HVAC system controlled by a thermostat. The thermostat includes a housing, a ring-shaped user-interface component, a processing system, and an electronic display. The method includes: on a touch-screen display in a location separate and apart from the thermostat, graphically displaying a circular region and one or more control symbols located thereon, the one or more control symbols graphically representing user manipulation of the ring-shaped user-interface component on the thermostat; detecting user input motion on the touch screen display in response to a touch and drag gesture by a user which is representative of user manipulation of the ring-shaped user-interface component on the thermostat; dynamically identifying a setpoint temperature value based on the detected user input motion; on the touch-screen display, dynamically displaying in real-time information representative of the identified set point temperature value on the circular region of the touch-screen display; waiting for an amount of time such that there is a relatively high likelihood that the identified setpoint temperature value corresponds to a setpoint temperature desired by the user; and wirelessly transmitting data representative of the identified setpoint temperature value.
[0008] According to some other embodiments, another method is described for interactively and graphically interfacing with a user of an HVAC system controlled by a thermostat. The thermostat comprising a housing, a ring-shaped user-interface component, a processing system and a rounded electronic display. On the thermostat display, a temperature marker symbol moves along an arc-shaped path near an outer periphery of the electronic display in response to rotation of the ring-shaped control member. The method includes: on a touch-screen display device in a location separate and apart from the thermostat, graphically displaying a circular region and an arc-shaped path near an outer periphery thereof, and a temperature control marker symbol that is positioned along the arc-shaped path of the circular region at a position associated with a current setpoint temperature value; detecting a user input gesture on the touch screen display in response to a touch and hold gesture by a user at a location on the arc-shaped path displayed on the circular region; gradually moving the temperature control marker symbol along the arc-shaped path on the circular region towards the location of the touch and hold gesture; dynamically identifying a setpoint temperature value based on the detected user input gesture; and wirelessly transmitting data representative of the identified setpoint temperature value.
[0009] According to some embodiments, a system is described for interactively and graphically interfacing with a user of an HVAC system. The described system includes: a thermostat with a housing, a ring-shaped user-interface component, a processing system configured to control an HVAC system based at least in part on a comparison of a measured ambient air temperature and a setpoint temperature value and a rounded electronic display under operative control of the processing. The described system also includes a touch screen display device operable from a location separate and apart from the thermostat, the touch screen display device including a touch screen display and a processing system communicatively coupled thereto. The display device processing system is programmed and configured to: graphically display a circular region and one or more control symbols located thereon, the one or more control symbols graphically representing user manipulation of the ring-shaped user-interface component on the thermostat; detect user input motion on the touch screen display in response to a touch and drag gesture by a user which is a representative of user manipulation of the ring-shaped user-interface component on the thermostat; dynamically identify a setpoint temperature value based on the detected user input motion; on the touch screen display, dynamically display in real-time information representative of the identified set point temperature value corresponding to a setpoint temperature desired by the user; waiting for an amount of time such that there is a relatively high likelihood that the identified setpoint temperature value corresponding to a setpoint temperature desired by the user; and wirelessly transmitting data representative of the identified setpoint temperature value so as to update the setpoint temperature value of the thermostat.
[0010] It will be appreciated that these systems and methods are novel, as are applications thereof and many of the components, systems, methods and algorithms employed and included therein. It should be appreciated that embodiments of the presently described inventive body of work can be implemented in numerous ways, including as processes, apparata, systems, devices, methods, computer readable media, computational algorithms, embedded or distributed software and/or as a combination thereof. Several illustrative embodiments are described below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The inventive body of work will be readily understood by referring to the following detailed description in conjunction with the accompanying drawings, in which:
[0012] FIG. 1 illustrates an example of a smart home environment within which one or more of the devices, methods, systems, services, and/or computer program products described further herein can be applicable;
[0013] FIG. 2 illustrates a network-level view of an extensible devices and services platform with which the smart home of FIG. 1 can be integrated, according to some embodiments;
[0014] FIG. 3 illustrates an abstracted functional view of the extensible devices and services platform of FIG. 2 , according to some embodiments;
[0015] FIG. 4 is a schematic diagram of an HVAC system, according to some embodiments;
[0016] FIGS. 5A-5D illustrate a thermostat having a visually pleasing, smooth, sleek and rounded exterior appearance while at the same time including one or more sensors for detecting occupancy and/or users, according to some embodiments;
[0017] FIGS. 6A-6D illustrate aspects of a graphical user interface a touch-screen device for remotely controlling a network connected programmable thermostat, according to some embodiments;
[0018] FIGS. 7A-7D illustrate aspects of a graphical user interface on a touch-screen device for remotely controlling a network connected programmable thermostat, according to some embodiments;
[0019] FIG. 8 is a flow chart showing aspects of updating devices with new user settings made remotely, according to some embodiments;
[0020] FIGS. 9A-9G illustrate aspects of a graphical user interface on a touch-screen device for remotely controlling a network connected programmable thermostat, according to some embodiments;
[0021] FIGS. 10A-D illustrate aspects of a graphical user interface on a touch-screen device for remotely controlling a network connected programmable thermostat, according to some embodiments;
[0022] FIGS. 11A-F illustrate aspects of a graphical user interface on a touch-screen device for remotely controlling a network connected programmable thermostat, according to some embodiments;
[0023] FIGS. 12A-E illustrate aspects of a graphical user interface on a touch-screen device for remotely controlling a network connected programmable thermostat, according to some embodiments;
[0024] FIGS. 13A-D illustrate aspects of a graphical user interface on a touch-screen device for remotely controlling a network connected programmable thermostat, according to some embodiments;
[0025] FIGS. 14A-B illustrate aspects of a graphical user interface on a touch-screen device for remotely controlling a network connected programmable thermostat, according to some other embodiments;
[0026] FIGS. 15A-C illustrate aspects of a graphical user interface on a touch-screen device for remotely controlling a network connected programmable thermostat, according to some other embodiments;
[0027] FIGS. 16A-C illustrate aspects of a graphical user interface on a touch-screen device for remotely controlling a network connected programmable thermostat, according to some other embodiments;
[0028] FIGS. 17A-C illustrate aspects of a graphical user interface on a touch-screen device for remotely controlling a network connected programmable thermostat operating in a range-mode, according to some other embodiments;
[0029] FIG. 18A illustrates a perspective view a user-friendly, non-circular thermostat according to some embodiments;
[0030] FIGS. 18B-18C illustrate aspects of a graphical user interface a touch-screen device for remotely controlling non-circular thermostat, according to some embodiments; and
[0031] FIG. 19 shows aspects of a thermostat graphical user interface implemented on a tablet computer with a touch screen device, according to some embodiments.
DETAILED DESCRIPTION
[0032] The subject matter of this patent specification relates to the subject matter of the following commonly assigned applications, each of which is hereby incorporated by reference in its entirety for all purposes: U.S. Ser. No. 13/624,875 filed Sep. 21, 2012 (Ref. No. NES0245-US); U.S. Ser. No. 13/434,560 filed Mar. 29, 2012 (Ref. No. NES0212-US); International Application No. PCT/US12/00007 filed Jan. 3, 2012 (Ref. No. NES0190-PCT); U.S. Ser. No. 13/466,815 filed May 8, 2012 (Ref. No. NES0179-US); U.S. Ser. No. 13/467,025 (Ref. No. NES0177-US); U.S. Ser. No. 13/351,688 filed Jan. 17, 2012, which issued as U.S. Pat. No. 8,195,313 on Jun. 5, 2012 (Ref. No. NES0175-US); U.S. Ser. No. 13/317,423 filed Oct. 17, 2011 (Ref. No. NES0159-US); U.S. Ser. No. 13/269,501 filed Oct. 7, 2011 (Ref. No. NES0120-US); U.S. Ser. No. 61/627,996 filed Oct. 21, 2011 (Ref. No. NES0101-PROV); U.S. Ser. No. 61/429,093 filed Dec. 31, 2010 (Ref. No. NES0037A-PROV); U.S. Ser. No. 61/415,771 filed Nov. 19, 2010 (Ref. No. NES0037); and U.S. Ser. No. 12/881,430 filed Sep. 14, 2010 (Ref. No. NES0002-US). The above-referenced patent applications are collectively referenced herein as “the commonly assigned” applications.
[0033] A detailed description of the inventive body of work is provided herein. While several embodiments are described, it should be understood that the inventive body of work is not limited to any one embodiment, but instead encompasses numerous alternatives, modifications, and equivalents. In addition, while numerous specific details are set forth in the following description in order to provide a thorough understanding of the inventive body of work, some embodiments can be practiced without some or all of these details. Moreover, for the purpose of clarity, certain technical material that is known in the related art has not been described in detail in order to avoid unnecessarily obscuring the inventive body of work.
[0034] As used herein the term “HVAC” includes systems providing both heating and cooling, heating only, cooling only, as well as systems that provide other occupant comfort and/or conditioning functionality such as humidification, dehumidification and ventilation.
[0035] As used herein the terms power “harvesting,” “sharing” and “stealing” when referring to HVAC thermostats all refer to thermostats that are designed to derive power from the power transformer through the equipment load without using a direct or common wire source directly from the transformer.
[0036] As used herein the term “residential” when referring to an HVAC system means a type of HVAC system that is suitable to heat, cool and/or otherwise condition the interior of a building that is primarily used as a single family dwelling. An example of a cooling system that would be considered residential would have a cooling capacity of less than about 5 tons of refrigeration (1 ton of refrigeration=12,000 Btu/h).
[0037] As used herein the term “light commercial” when referring to an HVAC system means a type of HVAC system that is suitable to heat, cool and/or otherwise condition the interior of a building that is primarily used for commercial purposes, but is of a size and construction that a residential HVAC system is considered suitable. An example of a cooling system that would be considered residential would have a cooling capacity of less than about 5 tons of refrigeration.
[0038] As used herein the term “thermostat” means a device or system for regulating parameters such as temperature and/or humidity within at least a part of an enclosure. The term “thermostat” may include a control unit for a heating and/or cooling system or a component part of a heater or air conditioner. As used herein the term “thermostat” can also refer generally to a versatile sensing and control unit (VSCU unit) that is configured and adapted to provide sophisticated, customized, energy-saving HVAC control functionality while at the same time being visually appealing, non-intimidating, elegant to behold, and delightfully easy to use.
[0039] FIG. 1 illustrates an example of a smart home environment within which one or more of the devices, methods, systems, services, and/or computer program products described further herein can be applicable. The depicted smart home environment includes a structure 150 , which can include, e.g., a house, office building, garage, or mobile home. It will be appreciated that devices can also be integrated into a smart home environment that does not include an entire structure 150 , such as an apartment, condominium, or office space. Further, the smart home environment can control and/or be coupled to devices outside of the actual structure 150 . Indeed, several devices in the smart home environment need not physically be within the structure 150 at all. For example, a device controlling a pool heater or irrigation system can be located outside of the structure 150 .
[0040] The depicted structure 150 includes a plurality of rooms 152 , separated at least partly from each other via walls 154 . The walls 154 can include interior walls or exterior walls. Each room can further include a floor 156 and a ceiling 158 . Devices can be mounted on, integrated with and/or supported by a wall 154 , floor or ceiling.
[0041] The smart home depicted in FIG. 1 includes a plurality of devices, including intelligent, multi-sensing, network-connected devices that can integrate seamlessly with each other and/or with cloud-based server systems to provide any of a variety of useful smart home objectives. One, more or each of the devices illustrated in the smart home environment and/or in the figure can include one or more sensors, a user interface, a power supply, a communications component, a modularity unit and intelligent software as described herein. Examples of devices are shown in FIG. 1 .
[0042] An intelligent, multi-sensing, network-connected thermostat 102 can detect ambient climate characteristics (e.g., temperature and/or humidity) and control a heating, ventilation and air-conditioning (HVAC) system 103 . One or more intelligent, network-connected, multi-sensing hazard detection units 104 can detect the presence of a hazardous substance and/or a hazardous condition in the home environment (e.g., smoke, fire, or carbon monoxide). One or more intelligent, multi-sensing, network-connected entryway interface devices 106 , which can be termed a “smart doorbell”, can detect a person's approach to or departure from a location, control audible functionality, announce a person's approach or departure via audio or visual means, or control settings on a security system (e.g., to activate or deactivate the security system).
[0043] Each of a plurality of intelligent, multi-sensing, network-connected wall light switches 108 can detect ambient lighting conditions, detect room-occupancy states and control a power and/or dim state of one or more lights. In some instances, light switches 108 can further or alternatively control a power state or speed of a fan, such as a ceiling fan. Each of a plurality of intelligent, multi-sensing, network-connected wall plug interfaces 110 can detect occupancy of a room or enclosure and control supply of power to one or more wall plugs (e.g., such that power is not supplied to the plug if nobody is at home). The smart home may further include a plurality of intelligent, multi-sensing, network-connected appliances 112 , such as refrigerators, stoves and/or ovens, televisions, washers, dryers, lights (inside and/or outside the structure 150 ), stereos, intercom systems, garage-door openers, floor fans, ceiling fans, whole-house fans, wall air conditioners, pool heaters 114 , irrigation systems 116 , security systems (including security system components such as cameras, motion detectors and window/door sensors), and so forth. While descriptions of FIG. 1 can identify specific sensors and functionalities associated with specific devices, it will be appreciated that any of a variety of sensors and functionalities (such as those described throughout the specification) can be integrated into the device.
[0044] In addition to containing processing and sensing capabilities, each of the devices 102 , 104 , 106 , 108 , 110 , 112 , 114 and 116 can be capable of data communications and information sharing with any other of the devices 102 , 104 , 106 , 108 , 110 , 112 , 114 and 116 , as well as to any cloud server or any other device that is network-connected anywhere in the world. The devices can send and receive communications via any of a variety of custom or standard wireless protocols (Wi-Fi, ZigBee, 6LoWPAN, etc.) and/or any of a variety of custom or standard wired protocols (CAT6 Ethernet, HomePlug, etc.). The wall plug interfaces 110 can serve as wireless or wired repeaters, and/or can function as bridges between (i) devices plugged into AC outlets and communicating using Homeplug or other power line protocol, and (ii) devices that not plugged into AC outlets.
[0045] For example, a first device can communicate with a second device via a wireless router 160 . A device can further communicate with remote devices via a connection to a network, such as the Internet 162 . Through the Internet 162 , the device can communicate with a central server or a cloud-computing system 164 . The central server or cloud-computing system 164 can be associated with a manufacturer, support entity or service provider associated with the device. For one embodiment, a user may be able to contact customer support using a device itself rather than needing to use other communication means such as a telephone or Internet-connected computer. Further, software updates can be automatically sent from the central server or cloud-computing system 164 to devices (e.g., when available, when purchased, or at routine intervals).
[0046] By virtue of network connectivity, one or more of the smart-home devices of FIG. 1 can further allow a user to interact with the device even if the user is not proximate to the device. For example, a user can communicate with a device using a computer (e.g., a desktop computer, laptop computer, or tablet) or other portable electronic device (e.g., a smartphone). A webpage or app can be configured to receive communications from the user and control the device based on the communications and/or to present information about the device's operation to the user. For example, the user can view a current setpoint temperature for a device and adjust it using a computer. The user can be in the structure during this remote communication or outside the structure.
[0047] The smart home also can include a variety of non-communicating legacy appliances 140 , such as old conventional washer/dryers, refrigerators, and the like which can be controlled, albeit coarsely (ON/OFF), by virtue of the wall plug interfaces 110 . The smart home can further include a variety of partially communicating legacy appliances 142 , such as IR-controlled wall air conditioners or other IR-controlled devices, which can be controlled by IR signals provided by the hazard detection units 104 or the light switches 108 .
[0048] FIG. 2 illustrates a network-level view of an extensible devices and services platform with which the smart home of FIG. 1 can be integrated, according to some embodiments. Each of the intelligent, network-connected devices from FIG. 1 can communicate with one or more remote central servers or cloud computing systems 164 . The communication can be enabled by establishing connection to the Internet 162 either directly (for example, using 3G/4G connectivity to a wireless carrier), though a hubbed network (which can be scheme ranging from a simple wireless router, for example, up to and including an intelligent, dedicated whole-home control node), or through any combination thereof.
[0049] The central server or cloud-computing system 164 can collect operation data 202 from the smart home devices. For example, the devices can routinely transmit operation data or can transmit operation data in specific instances (e.g., when requesting customer support). The central server or cloud-computing architecture 164 can further provide one or more services 204 . The services 204 can include, e.g., software update, customer support, sensor data collection/logging, remote access, remote or distributed control, or use suggestions (e.g., based on collected operation data 204 to improve performance, reduce utility cost, etc.). Data associated with the services 204 can be stored at the central server or cloud-computing system 164 and the central server or cloud-computing system 164 can retrieve and transmit the data at an appropriate time (e.g., at regular intervals, upon receiving request from a user, etc.).
[0050] One salient feature of the described extensible devices and services platform, as illustrated in FIG. 2 , is a processing engines 206 , which can be concentrated at a single server or distributed among several different computing entities without limitation. Processing engines 206 can include engines configured to receive data from a set of devices (e.g., via the Internet or a hubbed network), to index the data, to analyze the data and/or to generate statistics based on the analysis or as part of the analysis. The analyzed data can be stored as derived data 208 . Results of the analysis or statistics can thereafter be transmitted back to a device providing ops data used to derive the results, to other devices, to a server providing a webpage to a user of the device, or to other non-device entities. For example, use statistics, use statistics relative to use of other devices, use patterns, and/or statistics summarizing sensor readings can be transmitted. The results or statistics can be provided via the Internet 162 . In this manner, processing engines 206 can be configured and programmed to derive a variety of useful information from the operational data obtained from the smart home. A single server can include one or more engines.
[0051] The derived data can be highly beneficial at a variety of different granularities for a variety of useful purposes, ranging from explicit programmed control of the devices on a per-home, per-neighborhood, or per-region basis (for example, demand-response programs for electrical utilities), to the generation of inferential abstractions that can assist on a per-home basis (for example, an inference can be drawn that the homeowner has left for vacation and so security detection equipment can be put on heightened sensitivity), to the generation of statistics and associated inferential abstractions that can be used for government or charitable purposes. For example, processing engines 206 can generate statistics about device usage across a population of devices and send the statistics to device users, service providers or other entities (e.g., that have requested or may have provided monetary compensation for the statistics). As specific illustrations, statistics can be transmitted to charities 222 , governmental entities 224 (e.g., the Food and Drug Administration or the Environmental Protection Agency), academic institutions 226 (e.g., university researchers), businesses 228 (e.g., providing device warranties or service to related equipment), or utility companies 230 . These entities can use the data to form programs to reduce energy usage, to preemptively service faulty equipment, to prepare for high service demands, to track past service performance, etc., or to perform any of a variety of beneficial functions or tasks now known or hereinafter developed.
[0052] FIG. 3 illustrates an abstracted functional view of the extensible devices and services platform of FIG. 2 , with particular reference to the processing engine 206 as well as the devices of the smart home. Even though the devices situated in the smart home will have an endless variety of different individual capabilities and limitations, they can all be thought of as sharing common characteristics in that each of them is a data consumer 302 (DC), a data source 304 (DS), a services consumer 306 (SC), and a services source 308 (SS). Advantageously, in addition to providing the essential control information needed for the devices to achieve their local and immediate objectives, the extensible devices and services platform can also be configured to harness the large amount of data that is flowing out of these devices. In addition to enhancing or optimizing the actual operation of the devices themselves with respect to their immediate functions, the extensible devices and services platform can also be directed to “repurposing” that data in a variety of automated, extensible, flexible, and/or scalable ways to achieve a variety of useful objectives. These objectives may be predefined or adaptively identified based on, e.g., usage patterns, device efficiency, and/or user input (e.g., requesting specific functionality).
[0053] For example, FIG. 3 shows processing engine 206 as including a number of paradigms 310 . Processing engine 206 can include a managed services paradigm 310 a that monitors and manages primary or secondary device functions. The device functions can include ensuring proper operation of a device given user inputs, estimating that (e.g., and responding to) an intruder is or is attempting to be in a dwelling, detecting a failure of equipment coupled to the device (e.g., a light bulb having burned out), implementing or otherwise responding to energy demand response events, or alerting a user of a current or predicted future event or characteristic. Processing engine 206 can further include an advertising/communication paradigm 310 b that estimates characteristics (e.g., demographic information), desires and/or products of interest of a user based on device usage. Services, promotions, products or upgrades can then be offered or automatically provided to the user. Processing engine 206 can further include a social paradigm 310 c that uses information from a social network, provides information to a social network (for example, based on device usage), processes data associated with user and/or device interactions with the social network platform. For example, a user's status as reported to their trusted contacts on the social network could be updated to indicate when they are home based on light detection, security system inactivation or device usage detectors. As another example, a user may be able to share device-usage statistics with other users. Processing engine 206 can include a challenges/rules/compliance/rewards paradigm 310 d that informs a user of challenges, rules, compliance regulations and/or rewards and/or that uses operation data to determine whether a challenge has been met, a rule or regulation has been complied with and/or a reward has been earned. The challenges, rules or regulations can relate to efforts to conserve energy, to live safely (e.g., reducing exposure to toxins or carcinogens), to conserve money and/or equipment life, to improve health, etc.
[0054] Processing engine can integrate or otherwise utilize extrinsic information 316 from extrinsic sources to improve the functioning of one or more processing paradigms. Extrinsic information 316 can be used to interpret operational data received from a device, to determine a characteristic of the environment near the device (e.g., outside a structure that the device is enclosed in), to determine services or products available to the user, to identify a social network or social-network information, to determine contact information of entities (e.g., public-service entities such as an emergency-response team, the police or a hospital) near the device, etc., to identify statistical or environmental conditions, trends or other information associated with a home or neighborhood, and so forth.
[0055] An extraordinary range and variety of benefits can be brought about by, and fit within the scope of, the described extensible devices and services platform, ranging from the ordinary to the profound. Thus, in one “ordinary” example, each bedroom of the smart home can be provided with a smoke/fire/CO alarm that includes an occupancy sensor, wherein the occupancy sensor is also capable of inferring (e.g., by virtue of motion detection, facial recognition, audible sound patterns, etc.) whether the occupant is asleep or awake. If a serious fire event is sensed, the remote security/monitoring service or fire department is advised of how many occupants there are in each bedroom, and whether those occupants are still asleep (or immobile) or whether they have properly evacuated the bedroom. While this is, of course, a very advantageous capability accommodated by the described extensible devices and services platform, there can be substantially more “profound” examples that can truly illustrate the potential of a larger “intelligence” that can be made available. By way of perhaps a more “profound” example, the same data bedroom occupancy data that is being used for fire safety can also be “repurposed” by the processing engine 206 in the context of a social paradigm of neighborhood child development and education. Thus, for example, the same bedroom occupancy and motion data discussed in the “ordinary” example can be collected and made available for processing (properly anonymized) in which the sleep patterns of schoolchildren in a particular ZIP code can be identified and tracked. Localized variations in the sleeping patterns of the schoolchildren may be identified and correlated, for example, to different nutrition programs in local schools.
[0056] FIG. 4 is a schematic diagram of an HVAC system, according to some embodiments. HVAC system 103 provides heating, cooling, ventilation, and/or air handling for an enclosure, such as structure 150 depicted in FIG. 1 . System 103 depicts a forced air type heating and cooling system, although according to other embodiments, other types of HVAC systems could be used such as radiant heat based systems, heat-pump based systems, and others.
[0057] For carrying out the heating function, heating coils or elements 442 within air handler 440 provide a source of heat using electricity or gas via line 436 . Cool air is drawn from the enclosure via return air duct 446 through filter 470 , using fan 438 and is heated through heating coils or elements 442 . The heated air flows back into the enclosure at one or more locations via supply air duct system 452 and supply air registers such as register 450 . In cooling, an outside compressor 430 passes a gas such as Freon through a set of heat exchanger coils and then through an expansion valve. The gas then goes through line 432 to the cooling coils or evaporator coils 434 in the air handler 440 where it expands, cools and cools the air being circulated via fan 438 . A humidifier 454 may optionally be included in various embodiments that returns moisture to the air before it passes through duct system 452 . Although not shown in FIG. 4 , alternate embodiments of HVAC system 103 may have other functionality such as venting air to and from the outside, one or more dampers to control airflow within the duct system 452 and an emergency heating unit. Overall operation of HVAC system 103 is selectively actuated by control electronics 412 communicating with thermostat 102 over control wires 448 .
[0058] FIGS. 5A-5D illustrate a thermostat having a visually pleasing, smooth, sleek and rounded exterior appearance while at the same time including one or more sensors for detecting occupancy and/or users, according to some embodiments. FIG. 5A is front view, FIG. 5B is a bottom elevation, FIG. 5C is a right side elevation, and FIG. 5D is prospective view of thermostat 102 . Unlike many prior art thermostats, thermostat 102 has a sleek, simple, uncluttered and elegant design that does not detract from home decoration, and indeed can serve as a visually pleasing centerpiece for the immediate location in which it is installed. Moreover, user interaction with thermostat 102 is facilitated and greatly enhanced over known conventional thermostats by the design of thermostat 102 . The thermostat 102 includes control circuitry and is electrically connected to an HVAC system 103 , such as is shown in FIGS. 1-4 . Thermostat 102 is wall mountable, is circular in shape, and has an outer rotatable ring 512 for receiving user input. Thermostat 102 is circular in shape in that it appears as a generally disk-like circular object when mounted on the wall. Thermostat 102 has a large convex rounded front face lying inside the outer ring 512 . According to some embodiments, thermostat 102 is approximately 80 mm in diameter and protrudes from the wall, when wall mounted, by 32 mm. The outer rotatable ring 512 allows the user to make adjustments, such as selecting a new setpoint temperature. For example, by rotating the outer ring 512 clockwise, the realtime (i.e. currently active) setpoint temperature can be increased, and by rotating the outer ring 512 counter-clockwise, the realtime setpoint temperature can be decreased. The front face of the thermostat 102 comprises a clear cover 514 that according to some embodiments is polycarbonate, and a Fresnel lens 510 having an outer shape that matches the contours of the curved outer front face of the thermostat 102 . According to some embodiments, the Fresnel lens elements are formed on the interior surface of the Fresnel lens piece 510 such that they are not obviously visible by viewing the exterior of the thermostat 102 . Behind the Fresnel lens is a passive infrared sensor 550 for detecting occupancy, and the Fresnel lens piece 510 is made from a high-density polyethylene (HDPE) that has an infrared transmission range appropriate for sensitivity to human bodies. As shown in FIGS. 5A-5D , the front edge of rotating ring 512 , front face 514 and Fresnel lens 510 are shaped such that they together form a, integrated convex rounded front face that has a common outward arc or spherical shape gently arcing outward.
[0059] Although being formed from a single lens-like piece of material such as polycarbonate, the cover 514 has two different regions or portions including an outer portion 514 o and a central portion 514 i . According to some embodiments, the cover 514 is painted or smoked around the outer portion 514 o , but leaves the central portion 514 i visibly clear so as to facilitate viewing of an electronic display 516 disposed thereunderneath. According to some embodiments, the curved cover 514 acts as a lens that tends to magnify the information being displayed in electronic display 516 to users. According to some embodiments the central electronic display 516 is a dot-matrix layout (i.e. individually addressable) such that arbitrary shapes can be generated, rather than being a segmented layout. According to some embodiments, a combination of dot-matrix layout and segmented layout is employed. According to some embodiments, central display 516 is a backlit color liquid crystal display (LCD). An example of information displayed on the electronic display 516 is illustrated in FIG. 5A , and includes central numerals 520 that are representative of a current setpoint temperature, which in this case is 67 degrees F. Also shown on the electronic display 516 is a circular arrangement of tick-marks 570 on which the current ambient temperature is shown by ambient temperature marker 572 and the adjacent small numbers “70” indicating that the ambient temperature is currently 70 degrees F. Also shown in the tick-mark circle 570 is the setpoint caret symbol 580 which graphically indicates the current setpoint temperature, which in this case is 67 degrees F. The current setpoint temperature can be simply and intuitively adjusted by a user by rotating the ring 512 . In response to detecting rotation of ring 512 , setpoint caret 580 is in real time rotated along the tick mark circle 570 which has been found to provide useful feedback which enhances the user experience.
[0060] The thermostat 102 is preferably constructed such that the electronic display 516 is at a fixed orientation and does not rotate with the outer ring 512 , so that the electronic display 516 remains easily read by the user. For some embodiments, the cover 514 and Fresnel lens 510 also remain at a fixed orientation and do not rotate with the outer ring 512 . According to one embodiment in which the diameter of the thermostat 102 is about 80 mm, the diameter of the electronic display 516 is about 45 mm. According to some embodiments the gently outwardly curved shape of the front surface of thermostat 102 , which is made up of cover 514 , Fresnel lens 510 and the front facing portion of ring 512 , is spherical, and matches a sphere having a radius of between 100 mm and 150 mm. According to some embodiments, the radius of the spherical shape of the thermostat front is about 136 mm.
[0061] Motion sensing with PIR sensor 550 as well as other techniques can be used in the detection and/or predict of occupancy, as is described further in the commonly assigned U.S. Ser. No. 12/881,430 (Ref. No. NES0002-US), which is incorporated herein by reference. According to some embodiments, occupancy information is used in generating an effective and efficient scheduled program. A second downwardly-tilted PIR sensor 552 is provided to detect an approaching user. The proximity sensor 552 can be used to detect proximity in the range of about one meter so that the thermostat 102 can initiate “waking up” when the user is approaching the thermostat and prior to the user touching the thermostat. Such use of proximity sensing is useful for enhancing the user experience by being “ready” for interaction as soon as, or very soon after the user is ready to interact with the thermostat. Further, the wake-up-on-proximity functionality also allows for energy savings within the thermostat by “sleeping” when no user interaction is taking place our about to take place.
[0062] According to some embodiments, for the combined purposes of inspiring user confidence and further promoting visual and functional elegance, the thermostat 102 is controlled by only two types of user input, the first being a rotation of the outer ring 512 as shown in FIG. 5A (referenced hereafter as a “rotate ring” or “ring rotation” input), and the second being an inward push on head unit 540 until an audible and/or tactile “click” occurs (referenced hereafter as an “inward click” or simply “click” input). For such embodiments, the head unit 540 is an assembly that includes all of the outer ring 512 , cover 514 , electronic display 516 , and the Fresnel lens 510 . When pressed inwardly by the user, the head unit 540 travels inwardly by a small amount, such as 0.5 mm, against an interior metallic dome switch (not shown), and then springably travels back outwardly by that same amount when the inward pressure is released, providing a satisfying tactile “click” sensation to the user's hand, along with a corresponding gentle audible clicking sound. Thus, for the embodiment of FIGS. 5A-5D , an inward click can be achieved by direct pressing on the outer ring 512 itself, or by indirect pressing of the outer ring by virtue of providing inward pressure on the cover 514 , lens 510 , or by various combinations thereof. For other embodiments, the thermostat 102 can be mechanically configured such that only the outer ring 512 travels inwardly for the inward click input, while the cover 514 and lens 510 remain motionless. It is to be appreciated that a variety of different selections and combinations of the particular mechanical elements that will travel inwardly to achieve the “inward click” input are within the scope of the present teachings, whether it be the outer ring 512 itself, some part of the cover 514 , or some combination thereof. However, it has been found particularly advantageous to provide the user with an ability to quickly go back and forth between registering “ring rotations” and “inward clicks” with a single hand and with minimal amount of time and effort involved, and so the ability to provide an inward click directly by pressing the outer ring 512 has been found particularly advantageous, since the user's fingers do not need to be lifted out of contact with the device, or slid along its surface, in order to go between ring rotations and inward clicks. Moreover, by virtue of the strategic placement of the electronic display 516 centrally inside the rotatable ring 512 , a further advantage is provided in that the user can naturally focus their attention on the electronic display throughout the input process, right in the middle of where their hand is performing its functions. The combination of intuitive outer ring rotation, especially as applied to (but not limited to) the changing of a thermostat's setpoint temperature, conveniently folded together with the satisfying physical sensation of inward clicking, together with accommodating natural focus on the electronic display in the central midst of their fingers' activity, adds significantly to an intuitive, seamless, and downright fun user experience. Further descriptions of advantageous mechanical user-interfaces and related designs, which are employed according to some embodiments, can be found in U.S. Ser. No. 13/033,573 (Ref. No. NES0016-US), U.S. Ser. No. 29/386,021 (Ref. No. NES0011-US-DES), and U.S. Ser. No. 13/199,108 (Ref. No. NES0054-US), all of which are incorporated herein by reference.
[0063] FIGS. 5B and 5C are bottom and right side elevation views of the thermostat 102 , which has been found to provide a particularly pleasing and adaptable visual appearance when viewed against a variety of different wall colors and wall textures in a variety of different home environments and home settings. While the thermostat itself will functionally adapt to the user's schedule as described herein and in one or more of the commonly assigned incorporated applications, the outer shape is specially configured to convey a “chameleon” quality or characteristic such that the overall device appears to naturally blend in, in a visual and decorative sense, with many of the most common wall colors and wall textures found in home and business environments, at least in part because it will appear to assume the surrounding colors and even textures when viewed from many different angles.
[0064] According to some embodiments, the thermostat 102 includes a processing system 560 , display driver 564 and a wireless communications system 566 . The processing system 560 is adapted to cause the display driver 564 and display 516 to display information to the user, and to receiver user input via the rotatable ring 512 . The processing system 560 , according to some embodiments, is capable of carrying out the governance of the operation of thermostat 102 including various user interface features. The processing system 560 is further programmed and configured to carry out other operations as described further hereinbelow and/or in other ones of the commonly assigned incorporated applications. For example, processing system 560 is further programmed and configured to maintain and update a thermodynamic model for the enclosure in which the HVAC system is installed, such as described in U.S. Ser. No. 12/881,463 (Ref. No. NES0003-US), and in International Patent App. No. PCT/US11/51579 (Ref. No. NES0003-PCT), both of which are incorporated herein by reference. According to some embodiments, the wireless communications system 566 is used to communicate with devices such as personal computers and/or other thermostats or HVAC system components, which can be peer-to-peer communications, communications through one or more servers located on a private network, or and/or communications through a cloud-based service.
[0065] According to some embodiments, for ease of installation, configuration and/or upgrading, especially by a non-expert installer such as a user, the thermostat 102 includes a head unit 540 and a backplate (or wall dock) 542 . As is described hereinabove, thermostat 102 is wall mounted and has circular in shape and has an outer rotatable ring 512 for receiving user input. Head unit 540 of thermostat 102 is slidably mountable onto back plate 542 and slidably detachable therefrom. According to some embodiments the connection of the head unit 540 to backplate 542 can be accomplished using magnets, bayonet, latches and catches, tabs or ribs with matching indentations, or simply friction on mating portions of the head unit 540 and backplate 542 . Also shown in FIG. 5A is a rechargeable battery 522 that is recharged using recharging circuitry 524 that uses power from backplate that is either obtained via power harvesting (also referred to as power stealing and/or power sharing) from the HVAC system control circuit(s) or from a common wire, if available, as described in further detail in co-pending patent application U.S. Ser. No. 13/034,674 (Ref. No. NES0006-US), and Ser. No. 13/034,678 (Ref. No. NES0007-US), which are incorporated by reference herein. According to some embodiments, rechargeable battery 522 is a single cell lithium-ion, or a lithium-polymer battery.
[0066] FIGS. 6A-6D illustrate aspects of a graphical user interface a touch-screen device for remotely controlling a network connected programmable thermostat, according to some embodiments. In FIG. 6A , smartphone 600 is shown as an iPhone 4s running the Apple iOS operating system, although according to other embodiments the smartphone 600 could be a different device running a different operating system such as Android, Symbian, RIM, or Windows operating systems. Smart phone 600 has a touch sensitive display 610 on which various types of information can be shown and from which various types of user input can be received. For the example shown of an iPhone 4s, the display 610 is 3.5 inches measured diagonally. However, other smartphones may have slightly smaller, or larger displays, for example the iPhone 5 (4 inch diagonal), Samsung Galaxy S3 (4.8 inch diagonal), and Samsung Galaxy Note (5.3 inch diagonal). In any case the relatively small size of the smartphone touch screen display presents a challenge when designing a user-friendly interface. Note that while the user's hand 602 is shown in FIG. 6A to scale, in subsequent drawings, the user's hand is shown smaller in order not to overly obscure the features being described herein.
[0067] The display area shows a top information bar 620 that is generated by and is standard to the operating system of the phone 600 . In FIGS. 6A and 6B , the smart phone is oriented in a portrait orientation, such that the long edge of the display 610 is vertically oriented. An upper banner are 622 includes information such as the thermostat manufacture's logo, as well as the city name and current outdoor temperature for the location where the user's thermostat is installed. A main window area 630 shows a house symbol 632 with the name assigned in which thermostat is installed. A thermostat symbol 634 is also displayed along with the name assigned to the thermostat. For further details of user interfaces for remote devices such as smartphone 600 , see commonly assigned incorporated applications U.S. patent application Ser. No. 13/317,423 (Ref. No. NES0159-US), and Ser. No. 13/434,560 (Ref. No. NES0212-US). In response to a user touching the thermostat icon 634 with the finger 602 of the user, an animated transition is made to a simulated thermostat display area 636 . According to some embodiments, display area 636 which is larger than the area 634 and is configured to mimic or closely resemble the display on the thermostat that is being remotely controlled. In this case, the area 636 closely resembles electronic display 516 of thermostat 102 shown in FIG. 5A . Area 636 is circular which mimics the shape of thermostat display 516 and includes many or all of the same graphical elements, including a circular arrangement of tick-marks 670 , on which the current ambient temperature is indicated by the ambient temperature tick-mark symbol 672 . The ambient temperature is also shown in the small numerals “70” which indicates that the ambient temperature is 70 degrees F. The current setpoint temperature is shown by the caret symbol 680 as well as the large central numerals 674 . For further details on aspects of the graphical user interface of thermostats, see the commonly assigned U.S. Patent Publication No. 2012/0130546 A1 (Ref. No. NES0120-US), as well as commonly-assigned U.S. Pat. No. 8,195,313 (Ref. No. NES0175-US), both of which are incorporated by reference herein. When oriented in a portrait mode, according to some embodiments, a notification 638 is displayed that informs the user that further user interface features are available in landscape mode. When the user turns the smartphone 600 sideways, the screen transitions to a screen such as shown in FIG. 6C .
[0068] In FIG. 6C , a lower menu bar 640 has an arrow shape that points to the symbol to which the displayed menu applies. In the example shown in FIG. 6C , the arrow shape of menu 640 is pointed at the thermostat symbol 634 , indicating that the menu items, namely: Energy, Schedule, and Settings, pertain to the thermostat named “living room.” As in the case of FIG. 6A , in response to a user touching the thermostat icon 634 , an animated transition is made to a simulated thermostat display area 636 as shown in FIG. 6D .
[0069] FIGS. 7A-7D illustrate aspects of a graphical user interface on a touch-screen device for remotely controlling a network connected programmable thermostat, according to some embodiments. In FIG. 7A the user touches the setpoint caret 680 with the user's finger 602 and using a “dragging” gesture slides the tip of finger 602 in a counter clockwise direction along tick-mark circle 670 as shown by arrow 710 . In response to detecting the “touch and drag” gesture, the setpoint caret 680 is moved along the tick-mark circle 670 as indicated by arrow 712 so as to remain underneath the tip of the user's finger 602 . FIG. 7B shows a subsequent position of the users finger 602 and the setpoint caret 680 during the dragging gesture. According to some embodiments, the central numerals 674 are changed in real-time to indicate the setpoint temperature that corresponds to the current position of the setpoint caret 680 along the tick-mark circle 670 . The user's finger 602 and the setpoint caret 680 are continuing to move in a counter clockwise direction as indicated by arrows 712 and 714 respectively. In FIG. 7C the user finishes the dragging gesture at finger position shown. Note that the setpoint caret 680 now corresponds to a setpoint temperature of 61 degrees F. as indicated to the user by the central numerals 674 . At this point the user lifts finger 602 from the touch screen display and the setpoint temperature remains at the position shown in FIG. 7C . FIG. 7D shows the phone 600 with display 610 on which the simulated thermostat display area 636 indicates that the current setpoint temperature is 61 degrees F., following the remote adjustment by the user as shown in FIGS. 7A-C .
[0070] FIG. 8 is a flow chart showing aspects of updating devices with new user settings made remotely, according to some embodiments. In step 810 , the user's desire to change a temperature setpoint is detected on a remote device, for example as shown and described with respect to FIGS. 7A-C , supra, as well as FIGS. 9A-C ; 9 E-F; 10 A-D; 11 A-F; 12 A-F; 13 A-D; 14 A-D; 15 A-C; 16 A-C and 17 A-C, infra. According to some embodiments, the cloud server 164 shown in FIG. 1 keeps a “state” of the thermostat 102 which includes a number of parameters defining the thermostat. The “state” parameters are synchronized between the server 164 and each of the remote devices such as smart phone, tablet PCs, web clients, as well as with the thermostat 102 . Whenever any of the state defining parameters is changed on any of the remote devices then the cloud server updates all other remote devices as well as thermostat 102 . According to some embodiments, in order to reduce the impact on network data traffic, HVAC system components, and/or other remote devices as well as the effected thermostat(s), a delay period 812 is introduced on the remote device that has detected the user input prior to uploading the changed setting to the cloud server. It has been found that in some cases where the user interface allows the user to easily and simply make relatively large scale changes (e.g. changes in setpoint temperature of several degrees F. or more) it is useful to introduce a delay period. It has been found that in many cases the user makes one or more large scale changes followed by smaller scale “fine-tuning” changes. In other cases, it has been found that some users find a user interface so appealing and/or fun and easy to use that they are inclined to “play” with the user interface—thereby making several changes in a relatively short period of time. It has been found that a delay period of between 0.5 seconds and 5 seconds before transmitting the change to the cloud server is suitable for allowing the user to “fine-tune” the setting or to reduce the impact of “playing” with the interface. According to some embodiments a delay of 1-2 seconds has been found to be suitable. Note that during this delay period 812 , the user interface on the remote device remains responsive to user input in real time. In other words, the electronic display remains completely responsive to the user's touch and drag gestures a shown in FIGS. 7A-C , supra, as well as FIGS. 9A-C ; 9 E-F; 10 A-D; 11 A-F; 12 A-F; 13 A-D; 14 A-D; 15 A-C; 16 A-C and 17 A-C, infra, during the delay period 812 . Following the delay period 812 , in step 814 the remote device transmits the changed setting to such as via internet 162 to cloud server 164 as shown in FIG. 1 . A delay step 816 on the cloud server is shown which can according to some embodiments be used instead of, or in addition to the delay period 812 on the remote device that received the user input. In step 818 the cloud server transmits the new or modified setting to all other registered devices (such as other smart phones and/or tablet PCs, web clients, etc.) as well as one or more thermostats 102 (such as shown in various FIGS. herein). In step 820 the on thermostat(s) 102 are used to control the HVAC system using the new setpoint temperature setting. It has been found that introducing a delay as in steps 812 and/or 816 can significantly reduce the impact of settings changes on certain HVAC system components. For example, using a remote device interface, if a user rapidly changes the setpoint temperature the HVAC system may be repeatedly turned on and off in a short amount of time. Although some HVAC components, such as many AC compressors, have a built in “lock out” feature that prevents rapid cycling, not all components have such protection. For example, many fan motors do not have such protection. In such cases the delay such as in steps 812 and/or 816 are useful in preventing rapid cycling of HVAC components that are otherwise unprotected.
[0071] According to some other embodiments, other methods can be used to reduce the impact on network traffic and/or HVAC components. For example, according to one embodiment if repeated reversals of setpoint change are detected (e.g. the user increases, then decreases, then increases, then decreases the setpoint temperature) then the user-interface remains active and responsive to the user's inputs, but the user interface does not send the updated temperature to the servers until after a longer delay (i.e. greater than the delay specified in step 812 ). Variations on this example include successively longer delay times depending on how many repeated reversals and/or conflicting changes are made within a predetermined period of time. For example, if a change is made and then un-done more than three times within 10 seconds, then the delay period in step 812 is increased to 20 seconds.
[0072] FIGS. 9A-9G illustrate aspects of a graphical user interface on a touch-screen device for remotely controlling a network connected programmable thermostat, according to some embodiments. In FIG. 9A the user touches and holds the user's finger 602 at a location 900 on the tick-mark circle 670 . In response to the “touch and hold” gesture on the tic-mark circle 670 , the caret 680 begins to move towards the location 900 as shown by arrow 910 . FIG. 9B , shows the user interface display a short time later. The user is still holding finger 602 at location 900 . The caret 680 continues to move along the tick-mark circle 670 toward the location 900 as indicated by the arrow 912 . FIG. 9C shows the display 636 a short time later, when the caret 680 has arrived at the location 900 where the user has been holding finger 602 . The mode of operation shown in FIGS. 9A-F can be referred to as “come to my finger” since the caret 680 comes to the location on the tick-mark circle 670 where the user's finger is being held. Note that the large central numerals 674 have been changing during the “come to my finger” modes so as to provide the user a further indication as to what settings changes are being made in response to the user's interaction.
[0073] It has been found that in providing a user interface that allows the user to simply and intuitively make large-scale changes in setting such as setpoint temperature, it is desirable to reduce the risk of the user inadvertently making sudden “surprising” changes. One way to reduce this risk while still providing the ability to quickly make large-scale changes is to initially start the change at a low rate and then progressively increase the rate of change (i.e. to accelerate the rate of change of the setpoint temperature). FIG. 9D is a plot showing two different schemes for accelerating the rate of change of the setpoint temperature for large-scale setting changes such as the “come to my finger” type of setting change shown in FIGS. 9A-C and 9 E-G, according to some embodiments. In particular, both curve 920 and 922 start off at a relatively low rate of change as shown during period 924 . For example, the rate of change for the first few seconds is about 1-2 degrees F. per second, while the rate of change during period 926 can be 4-6 degrees F. per second. By providing an initially slow rate of change followed by a faster rate of change, the risk of surprising large scale changes can be significantly reduced while still providing the ability to quickly make large scale changes. According to some embodiments, an audible clicking or ticking sound is produced as the setpoint temperature is changing. For example a “click” sound can be associated with each 0.5 or 1 degree F. of change. When combined with the acceleration the increasing rate of the clicking or ticking sound provides an additional indication to the user to further enhance the user experience. FIGS. 9E , 9 F and 9 G show an example sequence of “come to my finger” adjustment through a touch and hold gesture, in which the user simply and quickly raises the setpoint temperature from 67 degrees F. to 81 degrees F.
[0074] FIGS. 10A-D illustrate aspects of a graphical user interface on a touch-screen device for remotely controlling a network connected programmable thermostat, according to some embodiments. FIG. 10A shows an initial state of display area 636 in which the heating setpoint temperature is set to 81 degrees F. In this case, the user drags finger 602 through a central portion of the display area 636 rather on or along the tick-mark circle 670 . In FIG. 10B , the user starts by touching the caret symbol 680 , but instead of dragging finger 602 along the tick-mark circle 670 (such as shown in FIGS. 7A-C , for example), the user drags finger 602 towards the central area of display area 636 as shown by arrow 1010 . In FIG. 10C , the user's finger 602 is touching the display area at a location 1002 . When the user's finger is close to the tick-mark circle 670 , such as at location 1000 , then the user interface interprets the gesture as a simple “touch and drag” gesture, such as shown in FIGS. 7A-C . However, at some point the position of finger 602 is so far off the tick-mark circle, such as position 1002 , that the user interface interprets the gesture as a new location and responds by implementing a “come to my finger” mode of adjustment such as shown in FIGS. 9A-C and 9 E-F. In FIG. 10D , the user's finger 602 continues to drag across the central area of display area 636 , as indicated by arrow 1012 , until it is located at location 1004 . In this case it is clear that a “come to my finger” adjustment mode should be implemented and the user interface responds by moving the setpoint caret symbol 680 towards the location 1004 as shown by arrow 1014 . In this way, “hybrid” gestures can be interpreted by the user interface. The user may start off by dragging the caret symbol 680 along the tick-mark circle 670 , but then at some point the user decides to take a “short cut” across the circle to a new location, at which point the user interface changes to “come to my finger” adjustment mode.
[0075] FIGS. 11A-F illustrate aspects of a graphical user interface on a touch-screen device for remotely controlling a network connected programmable thermostat, according to some embodiments. In this case, the user repeatedly taps finger 602 in the central portion of the display area 636 in order to make small scale adjustments in the setpoint temperature. FIG. 11A shows an initial state of display area 636 in which the heating setpoint temperature is set to 81 degrees F. In FIG. 11B , the user taps in a location within the lower half 1100 of the central area of display area 636 , and within the tick-mark circle 670 . In response to the single tap, the user interface changes the displayed setpoint lower by 1 degree F. in the central numerals 674 and the caret 680 is moved to a location corresponding to 1 degree F. lower. FIGS. 11C and 11D show the user interface response following repeated subsequent taps on the lower half of the central area, each time the setpoint temperature is lowered by 1 degree F. FIGS. 11E and 11F show the user interface response to taps in the upper half 1102 of the central area of display area 636 . Each tap in the upper area 1102 results in the setpoint temperature being raised by 1 degree F.
[0076] FIGS. 12A-E illustrate aspects of a graphical user interface on a touch-screen device for remotely controlling a network connected programmable thermostat, according to some embodiments. In this case, the user uses a touch and hold gesture with finger 602 in the central portion of the display area 636 in order to make large scale adjustments in the setpoint temperature. In FIG. 12A , the user uses a “touch and hold” gesture in a location within the lower half 1100 of the central area of display area 636 , and within the tick-mark circle 670 . In response to the touch and hold gesture, the user interface changes the displayed setpoint lower in the central numerals 674 and the caret 680 is moved to towards lower temperatures. FIGS. 12B , 12 C, 12 D and 12 E are a sequence of successively lower setpoints as the user's finger 602 is held in the lower area 1100 on the lower half of the central area. The setpoint is lowered until the user lifts finger 602 from the area 1100 . According to some embodiments, the large-scale change in response to the touch and hold gesture initially starts at low rate of change and subsequently accelerates to higher rates of change such as shown and described with respect to FIG. 9D so as to reduce the risk of inadvertent and surprising large scale changes in the setpoint temperature. The setpoint can also be raised using a touch and hold gesture in an upper area such as area 1102 shown in FIG. 11E .
[0077] FIGS. 13A-D illustrate aspects of a graphical user interface on a touch-screen device for remotely controlling a network connected programmable thermostat, according to some embodiments. In this case, the user repeatedly taps finger 602 on the tick-mark circle 670 area on one side or the other of the setpoint caret 680 on the display area 636 in order to make small-scale adjustments in the setpoint temperature. FIG. 13A shows an initial state of display area 636 in which the heating setpoint temperature is set to 81 degrees F. In FIG. 13B , the user taps in a location 1300 of the tick mark circle 670 which is adjacent to and to the left side of the setpoint caret symbol 680 (i.e. on the side that indicates lower temperatures than represented by the location of caret symbol 680 ). In response to the single tap, the user interface changes the displayed setpoint lower by 1 degree F. in the central numerals 674 and the caret 680 is moved to a location corresponding to 1 degree F. lower. FIG. 13C shows the user interface response following a tap a location 1302 of the tick mark circle 670 to the left of the setpoint caret symbol 680 . Note that the area 1302 has shifted slightly from the area 1300 since the active area for making this type of adjustment is relative to the location of the current setpoint caret symbol 680 . FIG. 13D show the user interface response following a tap a location 1304 of the tick mark circle 670 to the right of the setpoint caret symbol 680 (i.e. the side indicating higher temperatures). Each tap within the area to the right (higher temperature) side of the setpoint caret symbol results in the setpoint temperature being raised by 1 degree F.
[0078] Note that combinations of gestures described herein are contemplated and allow for intuitive means for a user to make setpoint changes using a remote touch screen device. For example in many cases the user may first make large-scale changes such as the “come to my finger” mode shown in FIGS. 9A-C and 9 E-G, or “touch and hold” gestures shown in FIGS. 12A-E , followed by a “fine tuning” or small-scale adjustment such as the “touch and drag” gesture shown in FIGS. 7A-C and/or “tapping” gestures such as shown in FIGS. 11A-F and/or FIGS. 13A-D . In many cases, the “transition” from one mode to the next is performed in a very natural and intuitive way for the user. For example, is a user starts by the a “touch and hold” gestures to make a large scale change using the “come to my finger” mode as shown in FIGS. 9A-C and 9 E-G, followed by a “touch and drag” gesture for fine tuning such as shown in FIGS. 7A-C , the user is not required to lift and then “re-touch” the touch screen. Rather, according to some embodiments, the user interface automatically switches “modes” when the caret has caught up with the user's finger position. In particular, from the starting point of either FIG. 9C or FIG. 9G , the user's finger 602 is in the position shown when the caret 680 “catches up” to the user's finger 602 . At this point, if the user simply drags finger 602 (without “re-touching”) with clockwise or counter clockwise along tick mark circle 670 , the user interface seamlessly enters the “touch and drag” mode shown in FIGS. 7A-C . In another example, the user interface automatically switches from a fine-tuning mode (e.g. the “touch and drag” gesture shown in FIGS. 7A-C ) to a large scale adjustment mode (e.g. the “come to my finger” mode shown in FIGS. 9A-C and 9 E-G). In this example, the user is dragging finger 602 along the tick-mark circle 670 in either a clockwise or counter clockwise direction (such as shown in FIGS. 7A-C ) and the caret 680 is following the position of the finger 602 . Then, at some point, the user accelerates the motion of finger 602 beyond a maximum predetermined rate of adjustment (e.g. 3-6 degrees F. per second). According to some embodiments, the user interface automatically switches to a “come to my finger” mode without requiring a “re-touch” by the finger 602 . When the user accelerates beyond the threshold rate, the caret begins to “lag” behind the user's finger and the user interface operates in a “come to my finger” mode such as shown in FIGS. 9A-C and 9 E-G. Note that the user is not required to lift and re-touch finger 602 to switch modes, rather the switch occurs automatically. In this way the transition between two adjustment modes is made automatically and in an intuitive and natural way so as to further enhance the user experience.
[0079] FIGS. 14A-B illustrate aspects of a graphical user interface on a touch-screen device for remotely controlling a network connected programmable thermostat, according to some other embodiments. In this case, the user performs a touch and drag gesture on display area 636 with two fingers 1402 and 1404 simultaneously in a twisting motion as indicated by arrows 1410 and 1412 as shown in FIG. 14A . FIG. 14B shows the resulting display which is displayed in real-time to the user. Note that the central numeral 674 and the setpoint caret symbol 680 are changed to give the user immediate feedback responsive to the two-finger twisting gesture. This type of gesture can be referred to as a “physical” emulation mode since the gesture used by the user mimics a gesture that would be used to rotate a physical dial. Note that as in the previously described embodiments an audible ticking or clicking sound can also be played to the user to further enhance the feedback and perceived responsiveness of the user interface.
[0080] FIGS. 15A-C illustrate aspects of a graphical user interface on a touch-screen device for remotely controlling a network connected programmable thermostat, according to some other embodiments. The user performs a touch and drag gesture along tick-mark circle 670 with finger 602 in a similar manner as shown in FIGS. 7A-C . However, in this case the user's finger 602 is not directly on the setpoint caret symbol 680 but rather is on some other location of the tick-mark circle 670 . Similarly to the gesture-adjustment mode shown in FIG. 14A-B , the mode shown in FIGS. 15A-C can be referred as a physical emulation mode since the gesture mimics one that would be used to rotate a physical dial. As shown in FIG. 15B , in response to the user's touch and drag gesture in the direction shown by arrow 1512 , the setpoint temperature is in real-time adjusted as shown by the setpoint caret symbol 680 and central numerals 674 . Similarly, in FIG. 15C , in response to the user's touch and drag gesture in the direction shown by arrow 1518 , the setpoint temperature is in real-time adjusted as shown by the setpoint caret symbol 680 and central numerals 674 . Note that as in the previously described embodiments an audible ticking or clicking sound can also be played to the user to further enhance the feedback and perceived responsiveness of the user interface.
[0081] FIGS. 16A-C illustrate aspects of a graphical user interface on a touch-screen device for remotely controlling a network connected programmable thermostat, according to some other embodiments. In this case, in response to the user's touch and drag gesture in a vertical direction (as shown by arrow 1610 ) by the user's finger 602 , a partially transparent vertical adjustment bar 1620 is displayed overlaying the display area 636 . Since the user's finger and the adjustment bar 1620 partially obstructs the user's view of the central numerals 674 , a small numerical side disk 1624 is displayed so that the user can easily view the temperature currently associated with the user's finger position. In FIG. 16B , in response to the user's touch and drag gesture in a downwards direction shown by arrow 1612 , the setpoint temperature is decreased as shown by the position of the setpoint caret symbol 680 , central numerals 674 and small disk 1624 . Similarly, In FIG. 16C , in response to the user's touch and drag gesture in an upwards direction shown by arrow 1614 , the setpoint temperature is increased as shown by the position of the setpoint caret symbol 680 , central numerals 674 and small disk 1624 . Note that according to some embodiments a small disk numerically displaying the temperature currently associated with the user's gesture can also be provided with any of the other adjustment modes described herein. According to some embodiments, a horizontal adjustment bar can be displayed in response to a horizontal touch and drag gesture as well, or instead of the vertical adjustment bar. Note that as in the previously described embodiments an audible ticking or clicking sound can also be played to the user to further enhance the feedback and perceived responsiveness of the user interface.
[0082] FIGS. 17A-C illustrate aspects of a graphical user interface on a touch-screen device for remotely controlling a network connected programmable thermostat operating in a range-mode, according to some other embodiments. As used herein the term “range mode” refers to a mode that automatically switches between heating and cooling to maintain an enclosure within a preferred temperature range. A range modes may be useful, for example, in climates that benefit from heating and cooling in the same day. In a range mode of operation there are two simultaneous temperature setpoints—a lower heating setpoint and a higher cooling setpoint. In FIGS. 17A-C the heating setpoint is displayed the user as numerals 1702 and heating setpoint caret symbol 1722 while the cooling setpoint is displayed using numerals 1704 and cooling setpoint caret symbol 1724 . The user can adjust either setpoint using a simple touch and drag gestures that is analogous to that shown in FIGS. 7A-C . For example in FIGS. 17A and 17B the user touches the cooling setpoint caret symbol 1724 and drags it to the right as shown by arrow 1710 . In response, the user interface in real-time displays the movement of the caret 1724 as well as the corresponding numerals 1704 . According to some embodiments, a minimum difference between the heating and cooling setpoints is enforced, so as to avoid overly energy wasteful conditions as well as the undesirable case of calling for both heating and cooling simultaneously. In the case shown in FIGS. 17A-C , a minimum difference of 5 degrees F. is enforced. Therefore, as shown in FIG. 17C , when the user attempts to move a setpoint towards the other that would caused less than the minimum difference, the other setpoint is also moved such that the minimum difference is enforce. In this case the user is moving the cooling setpoint downwards which causes the heating setpoint to also be lowered so as to maintain a minimum difference of 5 degrees F. According to some embodiments, the other adjustment methods described herein can also be used for adjusting a thermostat operating in range mode. For example, the “come to my finger” adjustment mode shown in FIGS. 9A-C and 9 E-F can be implemented to make large scale changes to the set point caret closest to the location of the “touch and hold” gesture. In another example, the tap gestures of FIGS. 11A-F can be implemented for range mode by dividing the central display area into quadrants rather than halves.
[0083] According to some embodiments, the techniques described herein are applied to non-circular thermostat displays. In particular, it has been found to be useful to display on the remote touch-screen device a graphical representation of the thermostat and/or the thermostat display in a fashion that mimics or closely resembles the thermostat and/or thermostat display. FIG. 18A illustrates a perspective view a user-friendly, non-circular thermostat 1800 according to some embodiments, comprising a frame 1802 and display/control strip 1804 . The display/control strip 1804 , which can comprise an LED screen behind an outwardly protruding glass touchscreen cover, is relatively long and relatively narrow, analogous to a stick of gum. According to some embodiments, the display/control strip 1804 is configured to be (i) sensitive to upward and downward finger swipes by the user to provide analog user inputs similar in purpose and effect to that of clockwise and counterclockwise rotations of the rotatable ring 512 of the thermostat 102 of FIG. 5A , supra, and (ii) inwardly pressable at one or more locations therealong, so as to provide an inward click input capability analogous to that provided with the rotatable ring 512 of the thermostat 102 of FIG. 5A , supra. Various other aspects of the visual display/control strip 1804 can be similar to those described above for the thermostat 102 , such as the entire display background turning blue for cooling cycles and turning orange for heating cycles. Displayed on the display/control strip 1804 is the current setpoint temperature readout 1806 . FIGS. 18B-18C illustrate aspects of a graphical user interface a touch-screen device for remotely controlling non-circular thermostat, according to some embodiments. Smart phone 600 with display 610 is shown displaying a rectangular display area 1810 that mimics the display strip 1804 on thermostat 1800 of FIG. 18A in that it uses the same aspect ratio, colors, fonts, etc. as the display strip 1804 . According to some embodiments, one or more of the adjustment techniques that are described herein with respect to a round thermostat can be applied to the case of the non-round thermostat. For example, FIGS. 18B and 18C show a touch and drag gesture by the user's finger 602 on the numerals 1820 that indicate the current setpoint temperature. Examples of other of the adjustment techniques described herein applied to non-round thermostats include: “come to my finger” adjustment modes such as shown in FIGS. 9A-C and 9 E-F; tap gestures such as shown in FIGS. 11A-F and/or 13 A-D; touch and hold gestures such as shown in FIGS. 12A-F ; as well as “physical emulation” modes such as the touch and drag gesture shown in FIGS. 15A-C .
[0084] While many of the embodiments that have been described thus far have been for a user interface on a remote touch-screen device for controlling a single programmable network connected thermostat, other variations of the described user interface techniques can be implemented, according to some embodiments. For example, according to some embodiments, the user interface described herein is used to control more than one physical thermostat simultaneously. According to another example, the user interface techniques described herein are used to control a “virtual” thermostat that does not physically exist but rather via network connection the HVAC system is controlled either locally or via a cloud server.
[0085] While many of the embodiments that have been described thus far have been shown in the context of a smart phone touch-screen device, it will be appreciated that the adjustment techniques are also applicable to other types of touch-screen devices such as game consoles, all-in-one computers, personal data assistants (PDAs) and tablet computers. FIG. 19 shows aspects of a thermostat graphical user interface implemented on a tablet computer with a touch screen device, according to some embodiments. Each of the features described herein with respect to a smart phone touch screen device, can also be implemented on other touch screen devices such as a tablet computer. In the example shown, an iPad 1900 is running the Apple iOS operating system, although according to other embodiments the tablet 1900 could be a different device running a different operating system such as the Android, Blackberry or Windows operating systems. Tablet 1900 has a touch sensitive display 1910 on which various types of information can be shown and from which various types of user input can be received. The display area shows a top information bar 1920 that is generated by and is standard to the operating system of the tablet 1900 . A main window area 1930 shows a house symbol 1932 with the name assigned in which thermostat is installed. For further details of user interfaces for remote devices such as tablet 1900 , see the commonly-assigned U.S. patent application Ser. No. 13/317,423 (Ref. No. NES0159-US), which is incorporated herein by reference. In the example shown in FIG. 19 the user is making a touch and drag gesture using finger 602 on the display area 1936 which is analogous to the adjustment mode described in FIGS. 7A-C .
[0086] Although the concepts relating to user interfaces for touch screens have been thus far described with respect to a thermostat, according to some embodiments these concepts are applicable beyond the immediate environment of HVAC to the smart home as a whole, as well as to network-based ecosystems within which the invention may be applicable. Other applications in a smart home setting, such as shown in FIG. 1 , that would benefit from remote control of a ring-based controller are contemplated. In particular, the techniques described herein are especially applicable to those systems that benefit from balancing user-responsiveness with impact on network traffic and protection of controlled equipment. Examples include electrical and/or electrical-mechanical remote controls where sudden large changes are highly undesirable and/or wasteful.
[0087] Various modifications may be made without departing from the spirit and scope of the invention. It is to be further appreciated that the term thermostat, as used hereinabove and hereinbelow, can include thermostats having direct control wires to an HVAC system, and can further include thermostats that do not connect directly with the HVAC system, but that sense an ambient temperature at one location in an enclosure and cooperatively communicate by wired or wireless data connections with a separate thermostat unit located elsewhere in the enclosure, wherein the separate thermostat unit does have direct control wires to the HVAC system. Accordingly, the invention is not limited to the above-described embodiments, but instead is defined by the appended claims in light of their full scope of equivalents.
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A system including a thermostat user interface for a network-connected thermostat is described. The system includes a thermostat including a frustum-shaped shell body having a circular cross-section and a circular rotatable ring, which is user rotatable for adjusting a setting of the thermostat. The system further includes a client application that is operable on a touch-screen device separate from the thermostat, that displays a graphical representation of a circular dial, that detects a user-input motion proximate the graphical representation, that determines a user-selected setpoint temperature value based on the user-input motion, that displays a numerical representation of the user-selected setpoint temperature value, and that wirelessly transmits to the thermostat data representative of the user-selected setpoint temperature.
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BACKGROUND
[0001] This invention relates to a portable light. In particular, it is concerned with a light which can be supported on a garment such as a cap, shirt, or jacket. In other instances, the light can be supported on a book, writing tablet, belt or the like.
[0002] Use of flashlights for mounting on clothing is known. This assists workers and security personnel in freeing the worker's hands so that other activities can be engaged in, while the light can be made to shine on a desired object.
[0003] The present invention is directed to an improved structure for mounting such a portable light on the garments or other paraphernalia associated with a person who needs to keep at least one hand, and preferably both hands, free for other activities.
[0004] The invention seeks to improve the known pocket lights and other techniques for mounting a flashlight in this manner.
SUMMARY
[0005] A portable flashlight includes a clip which has a base which is hingedly mounted with an anchor. A spring urges the base and the anchor together, and between the base and the anchor there can be located a support such as a garment or other paraphernalia associated with a user. The anchor and the base are engaged in the spring action by the clip effect so that the portable light can be securely mounted on the support which can be a user's garment.
[0006] On top of or as part of the anchor, there is a housing member, which mounts a movable, preferably, pivotally mounted head in which two LEDs are located. Movement of the head causes a protrusion on the head to move to a position different from a position when the head is closed on the support. The housing may be part of an overall housing for a combined anchor-housing structure.
[0007] When the head moves to the different position, it causes the protrusion to move relative to a circuit board in the housing and a circuit closes to activate the LEDs. This is effected by closing the circuit between batteries and the circuit board which are both located in the shell or casing formed the housing and the anchor.
[0008] The LEDs are mounted in the head which is located towards the rear of the portable light. A friction forming o-ring in the hinge which mounts the head with the housing acts to prevent the inadvertent closure or opening of the head relative to the housing. Accordingly, opening of the head on the housing causes the light to distend upwardly from the front face of the housing.
[0009] The light is further described with reference to the accompanied drawings and description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a perspective view viewed from the front of the portable light.
[0011] FIG. 2 is a side view of the portable light.
[0012] FIG. 3 is a top view of the portable light.
[0013] FIG. 4 is an under view of the portable light.
[0014] FIG. 5 is a front view of the portable light.
[0015] FIG. 6 is a rear view of the portable light.
[0016] FIG. 7 is an exploded view of the portable light showing the base plate, anchor plate, and hinge member with the head above the hinge member.
[0017] FIG. 8 is a view of the portable light with the head pivotably moved relative to the hinge member.
DETAILED DESCRIPTION
[0018] Features of an embodiment are now discussed from an illustrative perspective.
[0019] A portable light for mounting on a support comprises an anchor to be secured with a support. There is a housing portion mounted to the anchor, and the housing portion includes a head for the light source. A switch for the light source is operable by movement of the head for the light source relative to the housing. The head is hingedly movable relative to the housing, and the switch is operable to turn the light source on when the head is moved from the housing.
[0020] The anchor cooperates with a base plate and the light and is mounted on the anchor on a position opposite to the base. The base and the anchor are hingedly connected, and a spring urges the base plate and the anchor towards each other.
[0021] The base and the anchor effectively form a clip for securing the light to a support. As such that the material for the support is locatable between the base and the anchor, and thereby the light is secured to the support for the light.
[0022] The head includes at least two light sources. The light sources are angled relative to the head to the extend a field of illumination forwardly from the rear of the head toward the forward end of the head. The field of illumination partly overlaps in the area at the forward end of the housing. The two light sources are spaced apart at a position remote from the forward end of the housing and the rear end of the housing.
[0023] The head includes a protrusion for extending through an aperture in a top face the housing. The protrusion acts to operate a switch when the protrusion moves between a position relative to the housing thereby to activate a switch between closure and opening. The protrusion is relatively fixed on an under plate of the head. The activation of the switch is effected by the location of the head relative to the position of the housing.
[0024] The housing and anchor are fixedly formed relative to each other. There is a friction element in a hinge between the head and the housing, thereby to inhibit movement between the head and housing.
[0025] FIG. 1 shows an anchor, in the form of a plate or housing 10 , which has mounted on one side a base element or plate 11 . A spring hinge pivoting connection 12 is formed so that between the anchor 10 , base plate 11 and the pivot rod 12 , there is a biasing force to cause the anchor and base to be urged together to form a clip.
[0026] Movement of the tail, handle or finger grip 13 which extends from the base 11 about the pivot rod 12 a causes the front portion 14 of the base plate 11 to open. There is a leaf spring 12 b which is mounted at the area of the hinge 12 so that it applies the spring action on the hinge 12 . The hinge area has two downwardly directed pillars between which there is mounted a central portion of the base 11 in the spring-hinge relationship.
[0027] A garment or other paraphernalia of the user can enter through the mouth area 15 between the underside 16 of the anchor 10 and the top of the base element or plate 11 . The garment or other support will be located in the area 17 of the portable flashlight.
[0028] The anchor plate or housing 10 at its rear section has two upstanding pillars 18 and 19 . These form a second hinge about a pivot point or rod 20 .
[0029] A housing 21 is mounted on or with the anchor 10 , and there is also a slot 21 a which extends between the anchor 10 and the support 21 . The anchor 10 and the housing 21 are formed as a shell or casing.
[0030] Between the upstanding portions 18 and 19 there is a cylindrical sleeve 22 which is located for pivotal movement about the pivot or rod 21 . There is also a rubber o-ring 23 which is located around the axle rod 21 . This provides a friction effect so that the sleeve 22 is inhibited from unintentional movement about the axle rod 21 . The sleeve 22 is formed to extend from the rear portion of a head member 24 . The head member 24 also includes a base plate 25 .
[0031] On either side of 30 of the head 24 there are two tabs 24 a and 24 b. These tabs facilitate the opening and the closing of the head 24 and adjacency with the top panel 35 on top of the mating portion of the housing 21 . Portion 36 of the housing 21 extends from the plate 35 to the leading end of the housing 21 . The head 24 is mounted on a top of the housing, and the top is on the side remote from the anchor. The head has a small protrusion 24 c which clips into engagement in an indent 24 d formed on a step wall formation adjacent to a top face of the housing 21 . This ensures a positive locking engagement when the head 24 is in a closed position on the housing 21 .
[0032] At the forward end of the head member 24 there are two apertures 26 and 27 for accommodating two LEDs 28 and 29 respectively. The LEDs 28 and 29 are mounted on a plate 30 which in turn is connected to a circuit board 31 through appropriate connected through wiring 32 . There is a switch activating protrusion 33 from the base 25 of the head 24 . The protrusion 33 is fixed and is moveable as the head 24 moves so that it can have different positions to activate a switch related to the circuit board 31 . As such in the closed position the protrusion is accommodated in an aperture 34 which leads to one side of the circuit board 31 . The circuit board 31 is mounted in the support housing 21 in a cavity formed by the outer shell of the housing 21 , which mounts the head 24 . Movement of the protrusion 33 acts to close a circuit and open a circuit as necessary.
[0033] The anchor 10 provides a housing for batteries 36 and 37 which are connected through a spring conductor 38 mounted in the base of the anchor 10 . When the housing and the anchor are closed together with the batteries in position the circuit is essentially made. The protrusion 33 operates through the aperture 34 packs to open a close this up at so as to power and keep our the LEDs in the head formation 24 . The circuit board 31 is suitably and fixed to the top of the shell forming the housing 21 . The wires 32 runs from underneath the shell through the portion adjacent the cylindrical sleeve 22 and into the head member 24 to connect with the LEDs 28 and 29 .
[0034] Many other forms of the invention exist, each differing from the other in matters of detail only. For instance instead of a two part housing and anchor there can be more components or even a single component. Different kind of clip formations can be provided. There may not be a spring mechanism associated with the clip.
[0035] Instead of two LEDs there may more or less and instead of the LEDs there can be other light sources. The system can be used for different lighting needs, even without the mounting clip.
[0036] There can be other securing techniques for permitting the light to be affixed to a support. The base can be made of an inherently spring like type material with a bias towards the bottom of the anchor. Other structure can be used to permit the securing of the light to the support. For instance a clip like structure similar to a gem clip can be used. The anchor and support can be formed as a different form. It can be an integral unit in which the batteries and circuit are mounted.
[0037] It is to be understood that aspects of this invention could be used in other applications, such as for use where an artisan needs hands free to work a tool. The light can also be clipped in positions to aim at different targets while a persons hands are free for other functions. The angle of the light can change as necessary by opening the head to any desired degree. Arrows shown on FIG. 2 illustrate the movement possibilities of the head and the base. In some cases the clip may be dispensed with a releasable adhesive element employed on the anchor face for securing to a support. The head can be moved between a closed position and about 180 degrees opposite to the closed position.
[0038] The invention should be determined by the following claims.
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A portable light intended for mounting on a garment as support includes two LED light sources spaced apart towards the rear of the portable light. A clipped base below on anchor facilitates locating a garment between the anchor and the base, and a spring action urges the base toward the anchor. A hingedly movable head for the LEDs is mounted on the housing to move to and form the housing. An opening of the housing causes a switch in the housing to move between an opened and closed position such that a circuit actives or de activates the LED lights when the head opens or closes relative to the housing.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] None
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to systems for actuating one or more tools adapted for use in a wellbore.
[0004] 2. Description of the Related Art
[0005] Hydrocarbons such as oil and gas are recovered from a subterranean formation using a wellbore drilled into the formation. A number of tools are used throughout the process of drilling and completing the wellbore and also during the production life of the well. Many of these tools are energized using pressurized fluid that is self-contained in the tool, pumped downhole from the surface, or fluid that is produced from the well itself. These tools, which are sometimes referred to as hydraulically actuated tools, can be put to a number of uses.
[0006] One use for hydraulically actuated tools is to set a liner hanger. During drilling, the wellbore is lined with a string of casing that is cemented in place to provide hydraulic isolation and wellbore integrity. Commonly, multiple strings of casing are set in a well in a successive fashion. For example, a first string of casing is set in the wellbore after the well is drilled to a first depth and a second string of casing is run into the wellbore after the well is drilled to a second depth. The second string is set such that the upper portion of the second string of casing overlaps with the lower portion of the first string of casing. Any string of casing that does not extend back to the surface is generally referred to as a liner. The second string is then cemented into the wellbore as well. This process may be repeated as needed.
[0007] The liner hanger is used to hang or anchor a liner off of a string of other casing string. Several types of liner hangers are known in the art, which includes hydraulic liner hangers. In conventional hydraulic liner hangers, fluid is supplied under pressure into an annular space between a mandrel and a surrounding cylinder. The hydrostatic pressure of the fluid between the cylinder and the mandrel creates a force on the inner surface area of the cylinder that causes the cylinder to slide longitudinally.
[0008] Conventionally, the hydraulic liner hanger is set by applying a predetermined level of hydrostatic pressure to the liner hanger. That is, the liner hanger is run into the wellbore while in contact with a fluid having a first hydrostatic pressure and then actuated by increasing the pressure in the fluid. In an conventional arrangement, a ball is dropped into the wellbore and landed on a seat that is positioned generally downhole of the liner hanger. Fluid is then injected into the wellbore under pressure in order to actuate the hydraulic liner hanger.
[0009] Conventional hydraulic liner hangers can prematurely set if there is a pressure spike of sufficient magnitude in the drill string or if the pressure of the fluid external to the liner hanger unexpected drops. Conventional measures to prevent unintended setting of the liner hanger include the use of shear pins to mechanically restrain the cylinder while the liner assembly is run into the hole and closures or flow restriction devices that prevent fluid from entering the hydraulic liner hanger until the liner hanger is ready to be set.
[0010] These conventional measures have various drawbacks that include, but are not limited to, expense and tool complexity. These conventional measures may also impose undesirable constraints in deployment of the liner hanger such as permissible bounds for drilling fluid circulation pressures and flow rates. Moreover, the drawbacks of conventional hydraulic liner hanger are merely illustrative of the general drawbacks of wellbore tools in general that operate using hydrostatic pressure while in the wellbore.
[0011] The present invention addresses these and other drawbacks of the prior art.
SUMMARY OF THE INVENTION
[0012] In aspects, the present invention provides systems, devices, and methods for actuating a wellbore tool. An exemplary actuator made in accordance with the present invention is operatively coupled to the wellbore tool and conveyed into a wellbore via a work string. When the fluid in the work string reaches a predetermined applied pressure, the actuator undertakes a specified action such as longitudinal motion, rotation, expansion, etc that actuates or operates the wellbore tool. Premature actuation of the wellbore tool is prevented by applying to the actuator a resistive force that, alone or in cooperation with another mechanism, arrests or restrains movement of the actuator. This resistive force is generated by applied pressure of the fluid in the work string.
[0013] In one arrangement adapted for use on a drill string, the actuator includes an actuating member having a first and a second pressure chamber. The actuator also includes a pressure control device that can control the pressure in the two chambers. The two pressure chambers are independently hydraulically coupled to the fluid in the drill string and are arranged such that the pressures in the chambers generate opposing forces, a motive force and a resistive force, on the actuating member. In one embodiment, the actuating member includes a cylinder slidably disposed on a mandrel. The pressure chambers, which are formed between the cylinder and mandrel, communicate with the drill string fluid via ports formed in the mandrel. When needed, the pressure control device forms a hydraulic seal between the two chambers by using, for example, a sealing member and occlusion member. This hydraulic seal hydraulically couples the first pressure chamber to the fluid uphole of the hydraulic seal. The fluid downhole of the hydraulic seal and the second pressure chamber are largely isolated from pressure increases in the uphole fluid due to the hydraulic seal.
[0014] To activate the actuator and thereby actuate the wellbore tool, the pressure in the first chamber is increased relative to the pressure in second chamber. For example, after the hydraulic seal is formed by the pressure control device, a surface pump can be energized to increase the applied pressure in the fluid uphole of the hydraulic seal. When so energized by the pressurized fluid, the magnitude of the motive force generated by the first pressure chamber increases. When an adequate pressure differential exists, the motive force overcomes the resistive force and the actuating member is thereby displaced. The displacement of the actuating member in turn actuates the wellbore tool.
[0015] The actuator can be configured to operate liner hangers as well as other tools used in the wellbore. Moreover, in addition to drilling fluid, the pressurized fluid can be water, synthetic material, hydraulic oil, or formation fluids.
[0016] It should be understood that examples of the more important features of the invention have been summarized rather broadly in order that detailed description thereof that follows may be better understood, and in order that the contributions to the art may be appreciated. There are, of course, additional features of the invention that will be described hereinafter and which will form the subject of the claims appended hereto.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] For detailed understanding of the present invention, references should be made to the following detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings, in which like elements have been given like numerals and wherein:
[0018] FIG. 1 schematically illustrates one embodiment of an actuating tool made in accordance with the present invention;
[0019] FIGS. 2A and 2B schematically illustrate sectional views of an embodiment of an actuating tool made in accordance with the present invention that is adapted for use in connection with a liner hanger;
[0020] FIGS. 3A and 3B illustrate sectional views of embodiment of pressure chambers in accordance with the present invention;
[0021] FIG. 4 schematically illustrates one embodiment of a pressure control device made in accordance with the present invention that uses a closure;
[0022] FIG. 5 schematically illustrates one embodiment of a pressure control device made in accordance with the present invention that uses a flow restriction device; and
[0023] FIG. 6 schematically illustrates a sectional elevation view of a liner drilling system utilizing an actuating tool made in accordance with the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0024] The present invention relates to devices and methods for actuating wellbore tools. The present invention is susceptible to embodiments of different forms. There are shown in the drawings, and herein will be described in detail, specific embodiments of the present invention with the understanding that the present disclosure is to be considered an exemplification of the principles of the invention, and is not intended to limit the invention to that illustrated and described herein.
[0025] Referring initially to FIG. 1 , there is schematically illustrated one embodiment of a tool actuator 100 made in accordance with the present invention for operating a tool 10 conveyed via a work string 12 into a wellbore. The tool actuator 100 , as will be described in further detail below, operates in response to the applied pressure of the fluid. Applied pressure is generally defined as the total pressure applied by the fluid. The total pressure can be the hydrostatic pressure or can be the sum of several components such as hydrostatic pressure, dynamic pressure losses, and a pressure differentials caused by a device such as a surface mud pump or downhole pump. The actuator 100 includes an actuating member 102 connected directly or indirectly to the tool 10 , a first pressure chamber 104 , a second pressure chamber 106 , and a pressure control device 108 . The pressure control device 108 controls the pressure in each chamber 104 and 106 . The pressures in chamber 104 and 106 each generate a force on the actuating member 102 that substantially oppose one another. When the two chambers 104 and 106 have generally equal pressures, the opposing forces balance and the actuating member 102 remains stationary. When desired, the pressure control device 108 can vary the pressure in one of the two chambers 104 and 106 to cause a net force that causes the actuating member 102 react in a preset manner such as sliding, rotating, extending, retracting, etc. The reaction of the actuating member 102 thereby actuates the tool 10 .
[0026] In one arrangement, the actuator 100 is energized using pressurized fluid in a bore 14 of the work string 12 . The first and second pressure chambers 104 and 106 hydraulically communicate with the bore 14 via ports 110 and 112 , respectively. The first pressure chamber 104 generates a motive force F 1 adapted to displace the actuating member 102 whereas the second pressure chamber 106 generates a resistive force F 2 that temporarily or selectively offsets the force F 1 created by the first pressure chamber 104 . In such an arrangement, as long as chambers 104 and 106 communicate with pressurized fluid having the same hydraulic pressure, then the pressure values in the chambers 104 and 106 and corresponding generated forces will be substantially equal and the actuating member 102 will remain stationary, i.e., motion will be substantially arrested.
[0027] It should be appreciated that the actuating member 102 will remain stationary even if the applied pressure of the fluid in the bore 14 significantly and unexpectedly increases while the tool 100 is being run into the wellbore or sometime thereafter. This is so because the increased applied pressure will be applied to both chambers 104 and 106 . Thus, while the magnitude of the motive force F 2 may increase due to a pressure spike, the magnitude of the resistive force F 2 will also increase since the applied pressure of the fluid that energizes the first pressure chamber 104 also energizes the second pressure chamber 106 . Thus, the resisting force F 2 will act to cancel the motive force F 1 and thereby minimize the risk that the actuating member 102 will move. In like manner, if the pressure of the fluid external to the tool 100 unexpectedly drops, this pressure drop will not cause movement of the actuating member 102 because the second pressure chamber 104 , and the resistive force it generates, arrests movement of the actuating member 102 using the applied pressure of the fluid internal to the tool 100 .
[0028] When desired, the pressure control device 108 can cause a pressure imbalance or differential by allowing fluids having different applied pressures to communicate with each chamber 104 and 106 . Upon the pressure differential reaching a preset or predetermined value, the net force generated by the first pressure chamber 104 overcomes the opposing force of the second pressure chamber 106 and displaces the actuating member 102 , which then actuates the tool 10 .
[0029] It should be understood that the pressure chamber 106 need not provide the exclusive resistive force or mechanism for offsetting the motive force F 1 . For instance, a biasing member or spring can be utilized to provide a preset amount of resistance against movement of the actuating member 102 . Moreover, a shear pin or other frangible member can be used to increase the resistance the motive force F 1 must overcome before displacing the actuating member 102 . It should also be understood that the resisting force F 2 does not necessarily cause motion of the actuating member 102 . That is, the force F 2 can act to maintain the actuating member 102 at a limit or end point of a stroke of the actuating member 102 .
[0030] As will become apparent, the teachings of the present invention can be utilized for a variety of well tools and in all phases of well construction and production. Accordingly, the embodiments discussed below are merely illustrative of the applications of the present invention.
[0031] Referring now to FIGS. 2A and 2B , there is shown an embodiment of an actuator 120 adapted to actuate a liner hanger 50 . The liner hanger is conventionally arranged and includes devices such as slips 52 , a slip retainer 54 , and a shear pin 56 . A work string or other suitable conveyance device (not shown) can be used to convey this and other equipment into a wellbore. The actuator 120 is energized by the applied pressure of fluid in an inner bore 126 of the actuator 120 . The actuator 120 is coupled to the slip retainer 54 and is configured to move the slips 52 longitudinally when the applied pressure in the bore 126 reaches a predetermined value. During this longitudinal movement, the slips 52 extend radially outward and engage a casing wall.
[0032] In one embodiment, the actuator 120 includes an inner mandrel 128 concentrically disposed within a surrounding cylinder 130 . The cylinder 130 is adapted to slide longitudinally along the mandrel 128 . For ease of assembly, the cylinder 130 includes an upper cylinder section 132 , a spacer 134 , and a lower cylinder section 136 . The spacer 134 connects together the upper and lower cylinder sections 132 and 136 such that the cylinder 130 operates as one integral member. Other embodiments of the cylinder 130 , of course, could have greater or fewer constituent parts. The actuator 120 includes a first pressure cavity or chamber 140 formed in the upper cylinder section 132 and a second pressure cavity or chamber 142 formed in the second cylinder section 136 . Ports 144 and 146 formed in the inner mandrel 128 hydraulically couple the chambers 140 and 142 to the inner bore 126 . As will be described in further detail below, a pressure imbalance or differential between the two chambers 140 and 142 create a net force that causes longitudinal movement of the cylinder 130 .
[0033] Referring now to FIG. 3A , there is shown an exemplary arrangement of the chamber 140 for generating the motive force F 1 for displacing the cylinder 130 . During use, fluid in the bore 126 flows through the port 144 and fills the chamber 140 . The hydraulic pressure of the fluid in the chamber 140 applies a force to the surfaces defining the chamber 140 . Upon a predetermined pressure differential being caused between the chamber 140 and the chamber 142 , the cylinder 130 moves longitudinally along the direction specified with arrow B. To prevent or minimize the fluid from leaking out of the chamber 140 , the chamber can include seals 152 A and 152 B. In one embodiment, the seal 152 A is a movable sealing element that moves generally with the cylinder 130 and the seal 152 B is a stationary sealing element that is fixed to the inner mandrel 134 with suitable devices such as snap rings 153 . It should be understood, however, that other embodiments having different sealing elements may be utilized and that in still other embodiments the sealing elements can be omitted entirely.
[0034] Referring now to FIG. 3B , there is shown an exemplary arrangement of the chamber 142 for providing a resisting force F 2 that at least partially offsets the motive force F 1 to at least temporarily arrest of restrain motion of the cylinder 130 . During use, fluid in the bore 126 flows through the port 146 and fills the chamber 142 . The hydraulic pressure of the fluid applies a force to the surfaces defining the chamber 142 . This force urges the cylinder 130 in the direction specified with arrow C, which is substantially opposite of arrow B. Similar to the chamber 140 , the chamber 142 can include seals 162 A and 162 B. In one embodiment, the seal 162 A is a movable sealing element that moves generally with the cylinder 130 and the seal 162 B is a stationary sealing element that is fixed to the inner mandrel 128 with suitable devices such as snap rings 163 .
[0035] It will be understood that the magnitude of the pressure differential that initiates motion of the cylinder 130 will depend on factors such as frictional forces, the applied pressure external to the tool actuator 100 , the shear strength of any shear pins that may be used to secure the slip assembly, etc.
[0036] Referring now to FIGS. 1 , 2 A- 2 B, a pressure control device 170 selectively controls the pressures in the chambers 140 and 142 . The pressure control device 170 is positioned between the ports 144 and 146 to thereby selectively hydraulically isolate the chambers to which the ports 144 and 146 respectively connect. The pressure control device 170 can maintain substantially equal pressures in the chambers 140 and 142 and also vary the pressure in either of the two chambers 140 and 142 to cause a pressure imbalance therebetween. For example, the pressure control device 170 can for one period of time maintain substantially equal pressures in the chambers 140 and 142 and in a successive period of time selectively increase the pressure in the chamber 140 or decrease the pressure in chamber 142 . Numerous embodiments of the pressure control device 170 can be utilized, a few of which are discussed below.
[0037] Referring still to FIGS. 1 , 2 A- 2 B, in one embodiment, the pressure control device 170 includes a sealing member 172 and an occlusion member 174 that cooperate to at least temporarily occlude the bore 126 of actuator 120 . During run in of the wellbore tool 100 and before actuation is required, the sealing member 172 permits flow through the bore 126 . To initiation activation of the actuator 120 , the occlusion member 174 is introduced at the surface into the tubular connecting the actuator 120 to the surface (e.g., drill string, coiled tubing, production string, etc.). The occlusion member 174 travels down the tubular and mates with the sealing member 172 , which has an opening or passage equal to or less than the size of the occlusion member 174 . The occlusion member 174 can include a ball, a plug or other object configured to create a barrier across the sealing member 172 .
[0038] When the occlusion member 174 and the sealing member 172 mate, a hydraulic seal is formed between the port 144 and the port 146 . This seal, which does not need to be a “zero leakage” seal, enables a substantial pressure differential thereacross. Thus, the pressure chambers 140 and 142 are in communication with two hydraulically independent bodies of fluid. The two bodies of fluid need not be completely isolated from one another, e.g., there can be some fluid or hydraulic communication between the two fluid bodies.
[0039] Merely for convenience, the fluid in region 180 , which communicates with the chamber 140 , will be referred to as the uphole fluid and the fluid in region 182 , which communicates with the chamber 142 , will be referred to as the downhole fluid. The pressure of the uphole fluid can be controlled, e.g., increased, using a device such as a mud pump. Increasing the pressure of the uphole fluid will, of course, increase the pressure in the first chamber 140 . Because of the seal provided by the pressure control device 170 , the pressure of the downhole fluid and the fluid in the second chamber 142 remains mostly at hydrostatic pressure and are largely unaffected by the increased pressure in the uphole fluid.
[0040] Thus, initially, the motive force F 1 and resistive force F 2 will cancel due to the first and second chambers 140 and 142 receiving fluid having the same applied pressure. However, after occlusion of the bore 126 , the increase of applied pressure in the uphole fluid and in the first chamber 140 will cause a corresponding increase in the magnitude of the force F 1 . Because the pressure in the downhole fluid is mostly static, the resistive force F 2 does not change. At a predetermined pressure differential between the chambers 140 and 142 , the motive force F 1 overcomes the resistive force F 2 and longitudinally displaces the cylinder 130 . The cylinder 130 via its connection to the slip retainer 54 actuates or sets the slips 52 .
[0041] It should be appreciated that the temporary occlusion in the well provides a hydraulic path to the chamber inducing the motive force while isolating or uncoupling the chamber inducing the resistive force from that hydraulic path. In addition to a surface pump increasing hydraulic pressure, other devices such as a downhole pump or even pyrotechnics can be used to selectively increase hydraulic pressure in that hydraulic path.
[0042] In one arrangement, after the slips 52 are set, pressure of the uphole fluid is further increased until the sealing member 172 deforms and allows the occlusion member 174 to pass therethrough. After the occlusion member 174 unseats and passes through the sealing member 172 , hydraulic communication and fluid flow is reestablished along the bore 126 . In certain embodiments, the sealing member 172 and occlusion member 174 can be configured to permit multiple selectively blockages of the bore 126 .
[0043] Other selective bore restriction devices suitable for use in embodiments of the present invention are disclosed in U.S. Pat. 5,146,992 and U.S. patent application Ser. No. 10/602,578 filed Jun. 24, 2003, titled “Plug and Expel Flow Control Device,” both of which are commonly assigned and are hereby incorporated by reference for all purposes.
[0044] Referring now to FIG. 4 , there is shown a pressure control device 200 including an operator 202 that selectively displaces a closure member 204 . The closure member 204 is adapted to partially or completely seal the port 146 leading to the second pressure chamber 142 to thereby effectively isolate the second pressure chamber 142 . The pressure control device 200 can be adapted for either “one time” usage or multiple sealing and unsealing of the port 146 and can include a mechanical device, electro-mechanical device, hydraulic motor or other suitable device. For example, the operator can include a biasing member that applies a spring force, a pressure chamber actuated by hydraulic fluid, an electric motor, frangible devices that restrain the closure member 204 , etc.
[0045] Referring now to FIG. 5 , there is shown another embodiment of a pressure control device 210 that includes a flow restriction device 212 such as a valve that selectively controls flow across the port 146 . The flow rate of the flow restriction device 212 can be adjusted using a solenoid or other suitable device. In still other embodiments, the pressure control device can merely include ports of differing cross-section flow areas. Referring now to FIGS. 3A-3B , for example, the port (or ports) for the chamber 140 can have a larger cross-sectional flow area than the port (or ports) for the chamber 142 . The cross-sectional area differential can be selected such that the increase in hydraulic pressure in the bore is communicated faster to the chamber 140 than to chamber 142 to thereby provide a desired pressure differential between the chambers 140 and 142 .
[0046] It should be appreciated that the pressure control device, whatever the particular configuration, can control the degree to which hydraulic pressure in the bore is communicated to the pressure chambers. Moreover, it should be appreciated that fluid communication between the bore and the chambers need not be completely blocked in order to cause a desired pressure differential.
[0047] Referring now to FIG. 6 , there is shown a well construction facility 230 positioned over subterranean formation 232 . While the facility 230 is shown as land-based, it can also be located offshore. The facility 230 can include known equipment and structures such as a derrick 234 at the earth's surface 236 , a casing 238 , and mud pumps 240 . A work string 242 suspended within a well bore 244 is used to convey tooling and equipment into the wellbore 244 . The work string 242 can include jointed tubulars, drill pipe, coiled tubing, production tubing, liners, casing and can include telemetry lines or other signal/power transmission mediums that establish one-way or two-way data communication and power transfer from the surface to a tool connected to an end of the work string 242 . A suitable telemetry system (not shown) can be known types as mud pulse, electrical signals, acoustic, or other suitable systems. The tooling and equipment conveyed into the wellbore can include, but are not limited to, bottomhole assemblies, tractors, thrusters, steering units, drilling motors, downhole pumps, completion equipment, perforating guns, tools for fracturing the formation, tools for washing the wellbore, screens and other production equipment.
[0048] For illustrative purposes, the work string 242 is shown as including a drill string conveying a bottomhole assembly adapted for liner drilling (“liner drilling assembly”) 246 into the wellbore 244 . Exemplary liner drilling systems are discussed commonly assigned U.S. Pat. Nos. 5,845,722 and 6,196,336, which are hereby incorporated by reference for all purposes. The liner drilling assembly 246 includes a liner hanger 248 and an actuator 250 .
[0049] Referring now to FIGS. 2-6 , in an exemplary deployment, the liner drilling assembly 246 drills the wellbore 244 while the mud pump 240 circulates drilling fluid down the drill string 242 . The drilling fluid and entrained drill cuttings return up an annulus 252 formed by the drill string 242 and the wellbore 244 . During drilling, both pressure chambers 140 , 142 of the actuator 120 communicate with the drilling fluid in the drill string 244 and thus both pressure chambers 140 , 142 have approximately the same applied pressure as the drilling fluid in the drill string 242 . Accordingly, the opposing forces created by the pressures in the first and second chambers 140 , 142 are substantially equal and balance each other. Thus, advantageously, the actuator 120 remains substantially stationary regardless of the applied pressure value or pressure fluctuations inside the drill string 242 .
[0050] Once the liner drilling assembly 246 drills to a desired depth, the liner hanger 248 can be actuated in the following manner. In embodiments utilizing occlusion of the bore 126 , such as in FIG. 2A and 2B , drilling is halted and the occlusion member 174 is “dropped” into the drill string 242 . The occlusion member 174 flows down through the drill string 242 until it mates with the sealing member 172 to form an occlusion in the drill string 242 that hydraulically separates the first pressure chamber 140 from the second pressure chamber 142 . Thereafter, the mud pump 240 is operated to increase the applied pressure of the drilling fluid in the drill string 242 . Because of the occlusion, the applied pressure will increase only in the drilling fluid column inside the drill string 242 and uphole of the occlusion. The drilling fluid column in the drill string 242 and below the occlusion will remain at a lower applied pressure. Because the first pressure chamber 140 communicates with the fluid uphole of the occlusion, the applied pressure in first pressure chamber 140 increases relative to the pressure in the second pressure chamber 142 , which is communication with the drilling fluid downhole of the occlusion. Once a sufficient pressure differential is created between the first and second pressure chambers 140 , 142 , the net force applied by the first pressure chamber 140 urges the cylinder 130 longitudinally toward the slips 52 . Via the slip retainer 54 , the cylinder 130 drives the hanger slips 52 into engagement with the casing 238 .
[0051] In addition to being largely immune from pressure fluctuations during drilling, the actuator 120 also cannot be inadvertently actuated by pressure fluctuations when the liner drilling assembly 248 and drill string 244 are run into the hole (e.g., due to surge).
[0052] It should be appreciated that embodiments of the present invention provide numerous operational and situational advantages. For example, during drilling, formations having relatively a low fracture pressure could be encountered. In such a situation, increasing the pressure in the wellbore to set a liner hanger could expose the formation to excessive applied pressures. With embodiments of the present invention, it should be seen that the increased applied pressure used for actuating the tool actuator and thereby setting the liner hanger is confined mostly within the drill string. Thus, the formation is largely protected from damage that would otherwise occur if exposed to applied pressure in excess of the formation fracture pressure.
[0053] In another example, during drilling, the hydrostatic pressure external to the drill string could be significantly lower than the hydrostatic pressure within the drill string. Such a situation could arise, for instance, where drilling fluid lost to the formation reduces the hydrostatic pressure of the drilling fluid flowing up the wellbore annulus. Because operation of the tool actuator is initiated by actively controlling pressure within the drill string, the tool actuator is largely immune to the value the hydrostatic pressure of fluid external to the drill string or tool actuator. That is, even a dramatic drop in external pressure will not induce movement of the actuator since the resistive force opposing movement utilizes hydrostatic pressure within the actuator to prevent unintended activation of the actuator.
[0054] It should further appreciated that the teachings of the present invention can be readily applied to numerous tools outside the liner drilling context. For example, in certain applications, fluids such as water, acids, fracturing fluids, may be circulated in the wellbore. Also, formation fluids such as oil and water can be utilized in some circumstances to energize the actuator.
[0055] Some embodiments of the present invention can be adapted for use in situations where fluid pressure is not used to energize a tool or device. For example, some tools may be actuated or energized by vibrations, mud pulse, motion of the tool, frequency, electronic signals, etc. Aspects of the present invention, including, but not limited to the use of opposing forces, can be advantageously applied in such circumstances.
[0056] Further, it should be understood that while the embodiments described illustrate only two pressure chambers, additional pressure chambers can be added to further extend the utility of devices made in accordance with the present invention. In the same regard, while actuation of the a wellbore tool has been described, embodiments of the present invention can be readily adapted to return a wellbore tool to a condition prior to actuation (e.g., turn a tool on and off, set and set a tool, etc.)
[0057] Additionally, it should be understood that the terms such as “first” and “second” and “uphole” and “downhole” do not signify any specific priority, importance, or orientation but are merely used in better describe the relative relationships between the items to which they are applied. Also, the term longitudinal generally refers to a direction along the long axis of a wellbore or tool, but as noted above, the actuator is not limited to motion in any particular direction.
[0058] The foregoing description is directed to particular embodiments of the present invention for the purpose of illustration and explanation. It will be apparent, however, to one skilled in the art that many modifications and changes to the embodiment set forth above are possible without departing from the scope and the spirit of the invention. It is intended that the following claims be interpreted to embrace all such modifications and changes.
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An actuator operatively coupled to a wellbore tool is activated upon receiving fluid that a predetermined applied pressure. When the fluid string reaches the predetermined applied pressure, the actuator undertakes a specified action such as longitudinal movement, rotation, expansion, etc. that actuates or operates the wellbore tool. Premature actuation of the wellbore tool is prevented by applying a resistive force to the actuator that, alone or in cooperation with another mechanism, arrests movement of the actuator. This resistive force is generated by applied pressure of the fluid in the work string.
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