A nonwoven extending in a machine direction and a perpendicular cross-machine direction and having fibers bonded by a pattern of thermal bonds. The thermal bonds comprise larger bonds having an individual area of at least 1.0 mm2, in particular at least 1.5 mm2; and smaller bonds having an individual area of less than 1.0 mm2, in particular from about 0.10 mm2 to about 1.0 mm2. There are at least as many smaller bonds as larger bonds, the ratio of the number of smaller bonds may be in particular about two.

Absorbent articles for personal hygiene of the type indicated above are designed to absorb and contain body exudates, in particular large quantity of urine. These absorbent articles comprise several layers, typically a topsheet on the wearer-facing side, a backsheet on the garment-facing side and in-between an absorbent core, among other layers. An acquisition and/or a distribution layer may be further provided between the absorbent core and the topsheet. Topsheets are usually either made of a nonwoven or a formed film. Backsheets are typically made of a fluid-impermeable plastic film sometimes doubled on its external side by a nonwoven layer to provide a better feel. It is known to consolidate nonwovens by applying a thermal bonding pattern to the fibers. A commonly used technique involves passing the web of fibers between two calender rolls. One of the roll is typically smooth, and the other roll comprises protrusions having the shape and the disposition of the desired thermal bonding pattern. Typically the calender roll with the protrusion may be heated so that enough heat is applied to the web to locally melt the fibers of the web according to the desired thermal bonding pattern. This and other techniques to provide a bonding pattern on a nonwoven are disclosed in details for example in WO00/04215 (assigned to Fibervisions Inc.).
Various thermal bonding patterns have been suggested. WO01/12427A1 (assigned to First Quality Fibers, Inc) for example discloses a nonwoven with a non-symmetrical bonding configuration. The bonds have a generally oval shape and are oriented in different directions. US2014/0072767 (assigned to Pegas Nonwovens S.R.O.) discloses various bonding patterns including convex "wing" shapes and sigmoid "S" shapes. U.S. Pat. No. 8,530,722 (Rinnert et al.) discloses a colored topsheet having a basis weight of from 12 to 18 gsm and comprises a plurality of bonded points. Each of the bonded points has a surface area of from 2 mm2 to 5 mm2 and the cumulated surface area of the plurality of bonded points is from 10 to 25% of the total surface area of the top sheet. The bond points exemplified are generally round and have all the same shape.
The present inventors have found that many of the patterns of the prior art exhibit a relatively large amount of broken fibers that stick out of the surface of the nonwoven, referred to as fuzz. These broken fibers are generally undesirable as they reduce the quality perception of the nonwoven. The invention provides an efficient bonding pattern for the fibers of the nonwoven resulting in smaller broken fibers sticking out of the plane of the nonwoven ("fuzz") while keeping desirable attributes such as softness, flexibility, integrity, absorbency and cost-effectiveness.

Nonwoven thermal bonding pattern with low fuzz


A cylinder block including an upper block, a crankshaft and a lower block, has a plurality of bearing caps secured to the upper block so as to support the crankshaft for rotation. A generally rectangularly-shaped lower block casing is provided with a first reinforcing rib, located below each bearing cap and extending upright so as to connect opposite side walls of the casing, and a second reinforcing rib, extending from a fitting bracket. A transmission casing is fitted to the cylinder block through the fitting bracket. The second reinforcing rib terminates approximately below one of the bearing caps. The first reinforcing rib associated with the one of the bearing caps is separated from the bearing caps. The first reinforcing ribs are provided with structural stiffnesses such that a first reinforcing rib which is farther away from the one of the bearing caps than another first reinforcing rib has a lower structural stiffness than the other first reinforcing rib.

1. Field of the Invention
The present invention relates to an engine cylinder block and, more particularly, to the structure of a lower block section of a cylinder block of an automotive vehicle engine.
2. Description of Related Art
Typically, bearings are installed in engine cylinder blocks to support an engine crankshaft for rotation. If a bearing cap, holding an engine crankshaft for rotation in the engine cylinder block, slants, i.e., inclines with respect to the engine cylinder block during engine operation, the engine crankshaft will rub against the bearing cap and produce vibration. In order to avoid vibration of the engine crankshaft due to slanting of the bearing cap, various bearing cap structures have been proposed by which the structural rigidities of bearing caps are increased.
Each bearing cap in some engine cylinder blocks is bolted by side bolts to a skirt portion of the engine cylinder block. Such a bearing cap fixing structure is described in, for instance, Japanese Unexamined Patent Publication No. 59-88,241. It is also known to fix a bearing cap to both side walls and a bottom wall of a lower block of the engine cylinder block by bolts. Such a bearing cap fixing structure is known from, for instance, Japanese Unexamined Patent Publication No. 1-280,667.
Conventional bearing cap fixing structures have been designed without considering differences in vibration among the bearing caps. Consequently, although a conventional bearing cap fixing structure can improve the static supporting stiffness of a bearing cap, the conventional fixing structure is not always effective to suppress vibrations of the bearing cap while the engine vibrates. When the engine itself and a transmission structurally connected to the engine produce vibrations, the upper cylinder block, the lower cylinder block and the transmission are affected by the vibrations differently, and the upper and lower cylinder blocks partially deform in different ways. For instance, the upper and lower cylinder blocks may deform in different directions. If a bearing cap is fastened to both the upper and lower cylinder blocks in a location at which the upper and lower cylinder blocks deform differently, the bearing cap may possibly slant, cause the crankshaft to bend, and produce vibrations due to such bending.


An irrigation sprinkler nozzle comprising a nozzle body having an elongated range nozzle passageway formed therethrough, a spreader nozzle outlet fed by a pressure reducing chamber disposed below the passageway, and a tertiary nozzle outlet disposed laterally of the passageway and above the spreader nozzle outlet, the tertiary nozzle outlet receiving water from the pressure reducing chamber through a pressure reducing flow port.

This invention related to irrigation sprinkler nozzles, and more particularly to a new and improved sprinkler nozzle construction for enhancing the distribution pattern of water from a rotary sprinkler nozzle of the type including a primary or range nozzle and a secondary or spreader nozzle.
In many irrigation applications, particularly in commercial irrigation situations, irrigation sprinklers employ nozzles having two or more outlets, one nozzle, referred to as a "range nozzle" which is designed to produce a relatively large volume stream projected outwardly for maximum distance of throw, and another nozzle outlet referred to as a "spreader nozzle" which is designed to produce a smaller volume stream, and which is intended to fall out close in to the sprinkler for close in watering. In the ideal situation, the combined distribution pattern produced by the range nozzle and spreader nozzle would be a wedge shaped curve with maximum precipitation rate occurring at the sprinkler and decreasing linerally to zero at the maximum range.
While it is relatively straight forward to design a range nozzle to achieve maximum distance of throw, it is much more difficult to design a spreader nozzle to fill in the area between the sprinkler and the donut shaped area of coverage produced by the range nozzle. One reason why it is more difficult to design spreader nozzles to supply close in water is that small sized orifices and passageways have typically been thought necessary so that a relatively small droplet size spray is produced which will fall more quickly to the ground than the larger droplet size stream produced by the range nozzle. This is because smaller droplets have a much larger ratio of surface area to mass than larger droplets, so the small droplets lose energy through aerodynamic friction and slow down quickly allowing them to fall closer to the sprinkler than the larger droplets from the range nozzle. The use of small size orifices and passageways to produce small droplet size sprays have been found to have three major disadvantages. Firstly, small droplets are driven by even a slight breeze away from the intended destination, thereby producing erratic water distribution patterns. Secondly, it is very difficult to flow enough water through the small openings and passageways to produce sufficient water volume to achieve the desired close in precipitation rate, and thirdly, the small size of the openings and passages tend to result in clogs due to entrained particulate matter within the pressurized water system, thereby rendering the spreader nozzle ineffective.
Disclosed in U.S. Pat. No. 5,299,742, issued Apr. 5, 1994 and entitled IRRIGATION SPRINKLER NOZZLE is a rotary sprinkler nozzle construction which includes a spreader nozzle constructed in such a manner to enhance the distribution pattern of close in water without requiring small size orifices and passageways and which produces a spray pattern of controlled size and shape that is substantially unaffected by wind. As disclosed in that patent, the sprinkler nozzle includes a spreader nozzle constructed to produce a generally vertically oriented fan shaped spray with a lower portion of the spray being directed downwardly close in to the sprinkler, and an upper portion of the spray directed upwardly to interact with and become entrained in the stream from the range nozzle. By having a portion of the spray from the spreader nozzle become entrained in the stream from the range nozzle, a portion of the stream energy is transferred to the spray, thereby carrying the spray further away from the nozzle then would otherwise occur, and by directing a lower portion of the spray from the spreader nozzle downwardly, the amount of water applied in the immediate area around the sprinkler is increased. This then results in an overall enhancement of the distribution of water from the sprinkler nozzle without significant loss in overall range.
While use of nozzles constructed in accordance with the disclosure of the aforementioned '742 patent have been found to significantly enhance the distribution pattern produced by rotary sprinkler nozzles and have substantially eliminated the problem of spreader nozzle clogging, one problem that has been found to occur is that due to the relatively high velocity of the fan shaped spray produced by the spreader nozzle, the lower portion of the spray if directed downwardly close in to the sprinkler tends to impact on the adjacent soil with such force that erosion takes place and any seed therein planted is washed away. To eliminate this problem, it has been found necessary to direct the lower portion of the fan shaped spray produced by the spreader nozzle of the '742 patent further away from the sprinkler so that it does not fall to the ground until it has been projected outwardly approximately six to eight feet. This then results in a relatively dry donut shaped area extending outwardly around the sprinkler to approximately six to eight feet. As will become more apparent hereinafter, the present invention provides a new and improved nozzle construction which incorporates a third nozzle outlet in addition to a spreader nozzle of the type disclosed in the aforementioned '742 patent, and which provides close in water from the sprinkler outwardly to about six to eight feet. When the distribution pattern produced by the third nozzle outlet of the present invention is combined with the distribution pattern produced by the range nozzle and spreader nozzle, an overall precipitation distribution pattern is produced which very closely approximates the ideal wedge shaped pattern.

Rotary irrigation sprinkler nozzle with improved distribution


An attachment system for suspended drywall ceiling panels is disclosed. The attachment system comprises a panel support grid having a series of main-runners and cross-runners disposed with lower panel attachment surfaces in generally co-planar relationship and said grid having intersection points at main-runner and cross-runner crossings. The attachment system has attachment clips positioned at said intersection points interconnecting cross-runners and main-runners. The attachment clips being integrally constructed from light-gauge steel and having a box-like configuration with two opposing vertical walls and opposing upper and lower horizontal walls wherein the upper wall centrally separates into halves. The upper wall halves include upwardly extending tabs with tab connecting means releasably connectiing both halves. The opposing vertical walls of the attachment clip each having an oppositely extending cross-runner attachment flange. Said clips engaged in a sleeve-like manner to said main-runners by means of the box-like configuration separating at said upper wall to extend around outer portions of main-runners. A spacer key is struck out from the lower wall of the attachment clip and extends downwardly in a plane generally parallel with the longitudinal axis of the main-runner. The attachment system further comprises ceiling panels comprised of gypsum and being mechanically fastened to said lower panel attachment surfaces wherein adjacent panels meet at butt joints along cross-runners and spaced-apart open joints along main-runners being spaced apart by said spacer keys of the attachment clips.

1. Field of the Invention
This invention relates to an attachment system for suspended drywall ceiling panels.
2. Description of the Prior Art
Many present suspended ceiling system designs are widely used in the building construction industry. It has been consistently desirable to reduce installation time by utilizing a reduced number of components for drywall ceiling panel attachment. Although many past attempts have individually solved problems of fire resistancy, adaptability for attachment to diverse upper support framing and quick installation, none has sufficiently provided a system that solves all these problems while retaining simplified design.
Previous systems involve basic standard exposed grid systems with enlarged lower flanges to accept screw fasteners. Other variations provide differently shaped inverted-T cross-members and main-runners. While these attempts do simplify installation they are unable to accept recessed lighting fixtures and air distribution bars without the aid of supplemental trims or clips. They also fail to compensate for misaligned panels, or panel runout, particularly in large areas where supplemental support members have to be added. These additions significantly increase the overall system cost. Other shortcomings of these previous attempts are their inability to provide for soffitt or non-planar ceiling constructions. Thereby, difficulty in screw fastening to grid members occurs because of the design and size of mating flanges and the lack of rigid mounting provision necessary to eliminate ceiling uplift where required.
Typically, inverted-T runners, or channel-shaped runners are predominant conformations in the prior art. To provide for varieties of air handling and lighting accessories, additional components have been required along with alteration of conventional runner members. As additional components are required, fire ratings become more difficult to attain and manufacturing costs escalate.
Additionally, with the advent of the do-it-yourself consumer, who performs numerous types of repair and remodeling tasks, simplified installation has become a key goal in the industry. The ability of a system to provide variable location capability for many particular consumer residential uses has become necessitated as room limitations and requirements widely vary.
3. Objects of the Invention
It is a primary object of this invention to provide an attachment system for suspended drywall ceiling panels which involves simplified components facilitating ease of installation and having lowered costs.
It is also an important object of this invention to provide a fire resistant attachment system.
It is accordingly an object of this invention to provide a grid-like runner system having simplified interconnection between cross-runners and main-runners and adaptable means for attachment to upper support members.
It is an attendant object of this invention to provide an attachment system for suspended drywall ceiling systems adaptable with self-leveling or rigid hanger attachment to upper support members.
It is a concomitant goal of this invention to provide a facile attachment system for conventional gypsum ceiling panels by utilizing well-known self-drilling drywall screws.
It is also an object of this invention to provide an attachment system for suspended drywall ceiling panels featuring typical square-edged gypsum panels obviating the need for special edge configurations.
An allied goal of the invention is to afford simplified installation with a reduced number of components for both the do-it-yourself residential consumer and the skilled tradesman.

Attachment system for suspended drywall ceiling panels


In one embodiment, an impact and torque-absorbing module for a low profile lower limb prosthesis comprises two support members telescopingly engaged to permit axial and rotational motion therebetween. A resilient element resists axial displacement of the two support members, and a torque resisting cuff resists rotational displacement of the two support members. Precompression of the resilient element can reduce the size of the shock module making it more compact. The resilient element can also be replaced allowing adjustment of the shock absorption.

1. Field of the Invention
Embodiments of the present invention relate to lower limb prostheses in general, and, in certain embodiments, to a low profile shock module prosthesis having a resilient element and a torque-resisting cuff permitting rotational compliance between the lower leg and foot.
2. Description of the Related Art
Various types of lower limb prostheses are known in the prior art. Such devices generally include some form of attachment for coupling the device to the dorsal end of the limb and for extending to the ground to provide body support. Moreover, these devices generally constitute attempts to simulate the structure and/or the performance of the human leg and foot.
The various prostheses known in the prior art include some prostheses designed for people who have long residual limbs. For these patients, the calf and shin functions as the stump for prosthetic purposes. Thus, any prosthetic device utilized by the patient must either be relatively compact so as to be attachable below the point of amputation, or must be configured to accommodate the patient's shin and calf while attached thereto or higher up on the wearer's leg.
Among the features desirable in a lower limb prosthesis is the incorporation of some means for providing impact absorption and/or dampening during use of the prosthesis, without sacrificing the ability to reliably and predictably support the amputee's body weight. Such impact absorption permits the amputee to participate in activities with comfort and minimal stump trauma, hence allowing the amputee to be mobile for longer periods of time. Also desirable is a convenient means to selectively adjust the degree of impact absorption to suit the particular attributes (e.g., weight) and activity (e.g., walking, running, jumping, etc.) of the amputee.
Another desirable feature of lower limb prostheses is the incorporation of some means for allowing rotational compliance of the lower leg and foot relative to the stump of the amputee. Such rotation is beneficial and simulates the action of a natural human knee/ankle in a number of activities that involve the twisting of a person's body with respect to their planted foot, such as golf, tennis, and the like. Unrestrained compliance, however, is undesirable, as the foot would be free to twist unnaturally. Thus, it is desirable to incorporate a means for providing torsion-resistance against the rotation of a lower leg and foot relative to the stump of the amputee, and for returning the foot to its natural forward orientation after each rotational movement.
Impact absorption in lower limb prostheses can be achieved through the use of two or more elongated telescoping members with a resilient means disposed therebetween. Axial forces acting on such members cause relative longitudinal motion between them with the resilient means providing energy storage and release. Due to the vertical height of some of the pylons, those shock-absorbing prostheses cannot accommodate the shin and calf of an amputee with a long residual limb.
Thus, although the prior art illustrates many impact absorbing prostheses, few, if any, are designed to be compact enough for use by patients with long residual limbs. Furthermore, none of the prior art sets forth a lower limb prosthesis for amputees with long residual limbs that can provide both impact absorption and rotational compliance with torsion-resistance.

Low profile active shock module prosthesis


A method for generating and simulating test patterns to detect faults (57, 63) in an integrated circuit. The method comprises identifying all nets (27) which can potentially be shorted together. Each potential fault (34, 36, 37, 38, 39) is categorized as either a feedback fault or a non-feedback fault. A test pattern is generated to detect the selected potential fault. The test pattern is simulated to determine which additional potential faults are detected by the test pattern. Potential faults which are detected by the test pattern are deleted from the fault list (12). The method is repeated until no potential faults remain on the fault list (12).

The present invention relates, in general, to testing of digital circuits, and more particularly to generation of test patterns to detect bridging faults in digital circuits.
According to the prior art, three approaches are typically taken concerning the problem of bridging faults in VLSI circuits. The first approach is to ignore the bridging faults. The problem with such an approach is that bridging faults have been shown to be the most common type of failure in some technologies. In addition, as stuck-at test pattern generators become more efficient and as test vector compacting schemes reduce the number of patterns applied to the silicon the expected fault coverage of bridging faults decreases. The second approach taken for detecting bridging faults has been to use wired logic to model the failures. Such an approach involves using either wired-OR, or wired-AND, or both to model the bridging faults that can occur in the circuit. This modeling is appropriate for some technologies: shorts in ECL do behave like wired-ORs and shorts in NMOS do behave like wired-ANDs. However, in technologies such as CMOS, the wired logic model is not accurate.
The third approach, typically used for detecting bridging faults in CMOS circuits, uses a monitor on the power supply current. When shorted nodes are driven to opposite values a direct connection is present between the power and ground lines on the chip. A much larger current than the normal static current will be drawn by the chip. As a result, the only test generation requirement is to ensure that all of the nodes in the circuit are driven to opposite values at least once during the test. This method has four major drawbacks. The first is that current measurements take much more time than that required to apply a test vector and sample the outputs logically. Test equipment would have to be slowed down significantly so that the current monitors could function properly. The second drawback is that many CMOS VLSI chips do not implement pure CMOS, but may also contain circuits that dissipate static power thereby masking the fault. The third drawback is that transistors with large leakage currents may mask the effect of the bridging fault. Finally, even if the leakage currents are small, the total leakage current on a VLSI chip may be sufficient to mask the effect of a single bridging fault. As a result, these chips may have such a high normal static current that current monitoring would be impractical.
In addition, some way must be used to reduce the total nodes tested, since exhaustively testing every pair of nodes in a VLSI circuit would be uneconomically slow. According to the prior art, the physical routing of each metal line is traced to determine the nearest neighbor for each segment. Alternatively, capacitance values are calculated between adjacent and crossing lines. The lines that correspond to these capacitances are then identified as potential bridging faults. While accurate, these methods are extremely slow.
There is a need for a test pattern generator which will detect bridging faults in all technologies. The test pattern generator has to be able to function at the gate level since a lower-level simulation would be uneconomically slow. The test pattern generator must detect both faults which create a feedback loop and faults which create no feedback loop. The test patterns must not be order dependent. Finally there is a need for a method to rapidly extract nodes which could potentially short together to minimize the number of tests required.


A process for obtaining bimaterial parts by casting an aluminum alloy onto an insert coated with a metal film. In this process, the oxide layer is removed from the insert by treatment under vacuum, and then the insert is coated with a titanium based film by physical vapor deposition, and the insert is placed in a mold which is filled with a casting alloy.

The present invention relates to a process for obtaining bimaterial parts by casting an alloy around insert coated with a metal film.
The invention relates, more particularly, to the parts formed from an insert of aluminum or of another metal such as iron or copper, which is at least partly integrated into an aluminum alloy matrix, during a casting operation.
This particular structure is used, for example, for the manufacture of car parts such as engine cylinder heads, in order to try to locally modify their properties, and for inserting pipes into aeronautical molded parts.
In fact, it is known that such parts are locally subjected to stresses during use, in particular thermal stress, and that to avoid certain effects detrimental to their behavior, inserts having properties which better satisfy the stresses than the base material, are usually embedded in the parts.
However, it has been noted that the manufacture of these bimaterial parts was problematical, particularly in respect of the bond between the insert and the metal cast around it.
In fact, on the one hand, adherence between the constituent parts is not always as it should be, and as a result the mechanical properties or physical properties such as heat conductivity are inadequate; on the other hand, since the casting is made with the metal in the molten state by filling a mold in which the insert has been placed, if the metal forming the insert has a fusion temperature which is less than, or close to, that of the casting metal, the insert becomes deformed, and this is detrimental to correct localization thereof.

Process for obtaining bimaterial parts by casting an alloy around an insert coated with a metal film


A method for driving an address-display separated-type AC (Alternating Current) PDP (Plasma Display Panel) is provided which is capable of having sequentially and continuously wall charges be formed sufficiently on a scanning electrode and sustaining electrode even when a width of a scanning pulse is shortened. Driving operations of a scanning driver and sustaining driver for the scanning electrode and the sustaining electrode during a pre-discharge period are the same as those employed in the conventional method. Driving operations for the scanning electrode during a scanning period are also the same as those in the conventional method except following. At ending time of a period during which a scanning pulse is applied to the scanning electrode, a potential difference obtained by superimposing a writing wall charge forming pulse on a sustaining pulse is applied for 3 μsec to 5 μsec. At an ending time of the application of the potential difference, wall charges having amounts larger than those achieved by the conventional method can be accumulated on the scanning electrode and the sustaining electrode.

1. Field of the Invention
The present invention relates to a method for driving an address-display separated-type AC (alternating current) plasma display panel and a driving device using the method and more particularly to the method for driving the address-display separated-type AC plasma display panel (PDP) in which display with high definition is made possible and to the driving device using the above method.
The present application claims priority of Japanese Patent Application No. 2003-320461 filed on Sep. 11, 2003, which is hereby incorporated by reference.
2. Description of the Related Art
A plasma display panel (hereinafter may referred simply to as a "PDP") has, in general, many advantages in that it can be made thin, display on a large screen is made possible with comparative ease, it can provide a wide viewing angle, it can give a quick response, and a like. Therefore, in recent years, the PDP is being widely and increasingly used, as a flat display panel, for wall-hung televisions, public information boards, or a like.
The PDP is roughly classified, depending on its operating method, into two types, one being a DC (Direct Current)-type PDP and another being an AC-type PDP. The DC-type PDP is a PDP whose electrodes are exposed in a discharge space and which is operated in a direct-current discharge state. The AC-type PDP is a PDP whose electrodes are coated with a dielectric layer and are not exposed directly in a discharge gas and which is operated in an alternating-current discharge state. In the DC-type PDP, only while a voltage is being applied, discharge occurs. In the AC-type PDP, discharge is sustained by reversing a polarity of a voltage to be applied. The AC-type PDP is also classified into two types, one being a two-electrode type whose number of electrodes in a display cell is two and another being a three-electrode type whose number of electrodes in the display cell is three.
The three-electrode AC-type PDP will be described below. A plasma display panel 110 of the PDP, as shown in FIG. 18, is so constructed that it has a front substrate 120 and a rear substrate 121, both facing each other and ribs (partition walls) (not shown) are arranged at specified intervals in a matrix form, in a direction being vertical to a surface of a paper for the drawing, between the front substrate 120 and rear substrate 121. The above ribs arranged in the matrix form operate to play a role of providing discharge space 126ij (i=any one of 1, 2, . . . , and m, and j=any one of 1, 2, . . . , and n) and of partitioning display cells 131ij (13124 in FIG. 19). The "m" is equal to the number of horizontal scanning lines making up video signals in one frame and the "n" is equal to the number of pixels making up each of the horizontal scanning lines.
On each region on the front substrate 120 being placed by the rib apart from the rear substrate 121 at a specified interval and being partitioned by the rib are arranged one scanning electrode 122i and one sustaining electrode 123i (see FIG. 18) and on each region on the rear substrate 121 being placed apart from the front substrate 120 and being partitioned by the rib is arranged a data electrode 129j in a manner to be orthogonal to the scanning electrode 122i and sustaining electrode 123i. At each of intersecting points, arranged in a matrix form, where each of the scanning electrodes 122i, each of the sustaining electrodes 123i, and each of the data electrodes 129j intersect one another is formed one display cell 131ij (13124 in FIG. 19) making up the PDP.
A metal layer 132i is stacked on each of the scanning electrodes 122i and each of the sustaining electrodes 123i which are formed on the front substrate 120 made up of a glass substrate or a like (see FIG. 18) and a transparent dielectric layer 124 is stacked all over the metal layer 132i, each of scanning electrode 122i, each of the sustaining electrode 123i and then a protecting layer 125 is stacked on the transparent dielectric layer 124. The metal layer 132i is a layer formed to lower wiring resistance and the protecting layer 125 is a layer made of MgO (magnesium oxide) or a like and to protect the transparent dielectric layer 124 from discharge. On the other hand, a white dielectric layer 128 and a phosphor layer 127 are sequentially stacked all over the data electrodes 129j formed on the rear substrate 121 made up of a glass substrate or a like.
A discharge space 126ij in the three-electrode AC-type PDP 110 having such the configurations as above is filled with a mixed gas of He (helium), Ne (neon), Xe (xenon), and a like in a hermetically sealed manner. As a reference material describing such the conventional three-electrode AC-type PDP, "Society for Information Display 98 Digest" (SID 98 DIGEST) (Page 279 to 281, May, 1998) is available.
Next, configurations of a driving circuit for the conventional three-electrode AC-type PDP 110 are described by referring to FIG. 20. The driving circuit, as shown in FIG. 20, is made up of a scanning driver 134i, a sustaining driver 136, and a data driver 138j (not shown in FIG. 20). The scanning driver 134i applies a voltage described later to scanning electrodes Si (122i in FIG. 18 and S1, S2, . . . , Sm in FIG. 19) in a pre-discharge period 2, scanning period 3, and sustaining period 4 (shown in FIG. 21). The sustaining driver 136 applies a voltage described later to sustaining electrodes Ci (123i in FIG. 18 and C1, C2, . . . , Cm in FIG. 19) in the pre-discharge period 2, scanning period 3, and sustaining period 4. The data driver 138j (not shown) applies a data pulse to data electrodes Dj (129j in FIG. 18 and see FIG. 19) in the scanning period 3. Relations among the pre-discharge period 2, scanning period 3, and sustaining period 4 are as follows. That is, one field during which video signals are applied includes two or more sub-fields, each of which is made up of the pre-discharge period 2, scanning period 3, and sustaining period 4. During each of sub-fields, signals to be applied in one field are applied.
The scanning driver 134i, as shown in FIG. 20, is made up of a pre-discharge power feeding circuit 142 to feed a voltage, in the pre-discharge period 2, to be used for operations of resetting wall charges accumulated on a dielectric layer in the scanning electrode Si and operations of priming discharge, a scanning power feeding circuit 144 to feed a voltage ("Vbw") to be used to produce a scanning pulse to be applied in synchronization with a data pulse in the scanning period 3, a first power feeding circuit 146 to feed a voltage to be used to produce a sustaining pulse in the sustaining period 4, a pMOS (P-channel Metal Oxide Semiconductor Filed Effect Transistor) Ti1 whose source is connected to a line 147, an nMOS (N-channel MOS FET) Ti2 whose drain is connected to a drain of the nMOS Ti2 and a scanning control circuit 148 (shown in FIG. 20)). A source of the nMOS Ti2 is connected to a terminal of a ground potential GND. A connecting point between the pMOS Ti1 and nMOS Ti2 is connected to the scanning electrode Si. The sustaining driver 136 is made up of a second power feeding circuit 150 to feed a sustaining voltage Vs (C1, C2, . . . , Cm in FIG. 21), a switch Ts, a switch Tg, and a sustaining control circuit 152.
The pre-discharge power feeding circuit 142 is used to reset wall charges accumulated in the sustaining period 4 in a previous sub-field by using a sawtooth-like wave signal to be first applied in the pre-discharge period 2 (see FIG. 21) and to make priming discharge occur by using a sawtooth-like wave signal to be secondly applied in the pre-discharge period 2 and to output a voltage having such voltage waveforms as shown as S1, S2, . . . , Sm in FIG. 21 to be used for adjusting wall charges occurred by the priming discharge by using a sawtooth-like wave signal to be lastly applied in the pre-discharge period 2. The scanning power feeding circuit 144 is made up of a voltage source 145 and a switch Tbw whose one terminal is connected to the voltage source 145 and outputs the voltage "Vbw" from the voltage source 145 in the scanning period 3 to the line 147. The first power feeding circuit 146 outputs a voltage Vs to the line 147 in the sustaining period 4.
The scanning control circuit 148 operates to receive video signals and to feed each of control pulses described below to the pMOS Ti1 and nMOS Ti2. That is, the scanning control circuit 148 feeds a control pulse to turn ON the pMOS Ti1 to a gate of the pMOS Ti1 and a control pulse to turn OFF the nMOS Ti2 to a gate of the nMOS Ti2 in the pre-discharge period 2 during which the three kinds of sawtooth-like wave signals described above are fed from the pre-discharge power feeding circuit 142.
The scanning control circuit 148 feeds, in a period during which a scanning pulse is applied, a control pulse to turn OFF the pMOS Ti1 to a gate of the pMOS Ti1 and a control pulse to turn ON the nMOS Ti2 to a gate of the nMOS Ti2, while it feeds, in the scanning period 3 other than the period during which a scanning pulse is applied, a control pulse to turn ON the pMOS Ti1 to the gate of the pMOS Ti1 and a control pulse to turn OFF the nMOS Ti2 to the gate of the nMOS Ti2.
The scanning control circuit 148 repeats operations, alternately for every half of a period during which a sustaining pulse is applied in the sustaining period 4, that the pMOS Ti1 is turned ON and the nMOS Ti2 is turned OFF in a first half of a period during which a sustaining pulse is being fed and a control pulse to turn OFF the nMOS Ti2 is fed to the gate of the pMOS Ti1 and a control pulse to turn ON the nMOS Ti2 is fed to the gate of the nMOS Ti2 in a second half of the period during which the sustaining pulse is being fed. These operations drive a sustaining driver 149 on a side in which scanning operations are performed.
The sustaining control circuit 152 making up the sustaining driver 136 operates to receive video signals and to feed each of control pulses described below to the pMOS Ti1 and nMOS Ti2. That is, it feeds a control pulse to turn ON a switch Ts to an ON/OFF control inputting port of the switch Ts and a control pulse to turn OFF a switch Tg to an ON/OFF control inputting port of the switch Tg in a period during which a first sawtooth-like wave signal out of the above three kinds of the sawtooth-like signals fed in the pre-discharge period 2 is fed. Then, it also feeds a control pulse to turn OFF the switch Ts to the ON/OFF control inputting port of the switch Ts and a control pulse to turn ON the switch Tg to the ON/OFF control inputting port of the switch Tg in a period during which a second sawtooth-like wave signal is fed. Further, it also feeds a control pulse to turn ON the switch Ts to the ON/OFF control inputting port of the switch Ts and a control pulse to turn OFF the switch Tg to the ON/OFF control inputting port of the switch Tg both in a period during which a last sawtooth-like wave signal is fed and in the scanning period 3.
Also, the sustaining control circuit 152 repeats operations, in the sustaining period 4, alternately during every half period during which a sustaining pulse is being applied, by which a control pulse to turn OFF the switch Ts is fed to the ON/OFF control inputting port of the switch Ts and a control pulse to turn ON the switch Tg is fed to the ON/OFF control inputting port of the switch Tg in a first half of the period during which the sustaining pulse is being fed and a control pulse to turn ON the switch Ts is fed to the ON/OFF control inputting port of the switch Ts and a control pulse to turn OFF the switch Tg is fed to the ON/OFF control inputting port of the switch Tg in a second half of the period during which the sustaining pulse is being fed. One terminal of the switch Ts is connected to the second power feeding circuit 150 and another terminal of the switch Ts is connected to one terminal of the switch Tg. A connecting point between the switch Ts and switch Tg is connected to the sustaining electrode Ci. Another terminal of the switch Tg is connected to a port for a ground potential.
Next, a method for driving the three-electrode address-display separated-type AC PDP 110 having configurations as described above is explained. Now, let it be assumed for explanation that operations during a sub-field 5 start (see FIG. 21). Amounts of wall charges to be formed, by discharge, on a dielectric layer of each electrode in a display cell differ depending on whether or not sustaining discharge has occurred in a sustaining period in a sub-field existing immediately before the sub-field 5. If next writing is done irrespective of such the difference in the amounts of wall charges, occurrence of writing discharge caused by the amounts of wall charges becomes difficult and erroneous writing occurs.
To solve this problem, conventionally, the scanning driver 134i operates to perform initializing (resetting) operations and priming discharge operations in the pre-discharge period 2 in the sub-field 5. That is, the scanning driver 134i turns ON the pMOS Ti1 and turns OFF the nMOS Ti2 to apply a first sawtooth-like wave signal to the scanning electrode Si and the sustaining driver 136 turns ON the switch Ts and OFF the switch Tg from a second half of a period during which a last sustaining pulse fed in the sustaining period 4 in the previous sub-field is being fed. In the period during which the above first sawtooth-like wave signal is being fed to the scanning electrode Si, a voltage Vs is applied to the sustaining electrode Ci and wall charges formed in the sustaining period 1 in the previous sub-field are reset.
Then, the scanning driver 134i turns ON the pMOS Ti1 and OFF the nMOS Ti2 to apply a second sawtooth-like wave signal to the scanning electrode Si, while the sustaining driver 136 turns OFF the switch Ts and ON the switch Tg to apply a ground potential to the sustaining electrode Ci, causing priming discharge to occur. Further, the scanning driver 134i turns ON the pMOS Ti1 and OFF the nMOS Ti2 to apply a last sawtooth-like wave signal to the scanning electrode Si and the sustaining driver 136 turns ON the switch Ts and OFF the switch Tg to apply the voltage Vs to the sustaining electrode Ci in a period during which the above last sawtooth-like wave signal is being applied and in the scanning period 3, thus causing wall charges occurred by priming discharge to be adjusted. The priming discharge operations and wall charge adjusting operations are performed to achieve easy writing of display data to be done in a one-pass scanning manner according to display data, that is, to realize easy occurrence of discharge in a display cell.
When the pre-discharge period 2 described above ends, operations in the scanning period 3 start. From starting time of the scanning period 3, a voltage "Vbw" begins to be output from the voltage source 145 in the scanning driver 134i to the line 147 and to be applied to the scanning electrode Si and, as described above, from starting time of the application of the last sawtooth-like wave signal in the pre-discharge period 2, the voltage "Vs" begins to be applied to the sustaining electrode Ci from the sustaining driver 136. Time of termination of the application of the voltage "Vbw" to be output by the scanning driver 134i to the line 147 is the same as ending time of the scanning period 3 and time of termination of the application of the voltage Vs to be applied by the sustaining driver 136 to the sustaining electrode Ci is the same as ending time of the scanning period 3.
On the other hand, to the gate of the pMOS Ti1 is applied a pulse to turn OFF the pMOS Ti1 from the scanning control circuit 148 with same timing with which display data (pixel data) existing on the i-th scanning line is applied, which makes up video signals fed in one field, for example, display data to be fed to the data electrode Dj is fed and, at the same time, to the gate of the nMOS Ti2 is applied a pulse to turn on the nMOS Ti2 by the scanning control circuit 148 with same timing as described above.
Therefore, while a scanning pulse (see reference number 6 in FIG. 21) is being sequentially applied to the scanning electrodes S1 to Sm (see reference numbers S1 to Sm) in the sub-field 5, n-pieces of data pulse (see reference number 7) in each sub-field is applied to each of the data electrodes (see reference numbers D1 to Dn in FIG. 21) corresponding to each data pulse in the scanning period 3 during which the scanning pulse is being applied to each scanning electrode Si.
In a display cell (in the intersecting portion between the scanning electrode and data electrode) to which data pulse is fed, since a voltage between the scanning electrode Si and the data electrode Dj is boosted and, after the application of the voltage, writing discharge occurs between the scanning electrode Si and data electrode Dj with some time delay (hereinafter called a discharge delay), positive wall charges are formed on a side of the scanning electrode Si. Also, between the sustaining electrode Ci and scanning electrode Si (between surface electrodes) where a large bias is being applied in a potential state at the discharge time, since movements of electric charges occur by an electric field generated between the electrodes, negative wall charges are formed on the sustaining electrode Ci.
Contrary to the above case, in a display cell (pixel) to which a data pulse 7 is not fed, since a voltage between the scanning electrode Si and data electrode Dj is not boosted, writing discharge does not occur and a wall charge change that may occur in such the case where the data pulse 7 is applied does not occur.
Thus, depending on whether or not the data pulse 7 is applied to a display cell, two types of states of wall charges can be made to occur between the scanning electrode Si and sustaining electrode Ci. When these two states of wall charges are made to continue to exist during the subsequent sustaining period 4, display or no-display of the pixel continues. This operation is explained below.
When the application of a scanning pulse 6 to all the scanning electrodes Si (from i=1 to i=m) is terminated, operations in the sustaining period 4 start. A sustaining pulse is applied, by the sustaining driver 149 and sustaining driver 136 on a side where scanning operations are performed, alternately to all the scanning electrodes Si to Sm and all the sustaining electrodes Ci to Cm in a specified period. To the scanning electrode Si is first applied a positive sustaining pulse and then a negative sustaining pulse. The positive sustaining pulse and negative sustaining pulse are alternately applied. To the sustaining electrode Ci is applied a negative sustaining pulse first and then a positive sustaining pulse. The negative sustaining pulse and positive sustaining pulse are alternately applied. A voltage of each of these sustaining pulses is set at a voltage at which discharge (called surface discharge) between a scanning electrode Sk and a sustaining electrode Cl does not start in a display cell 131K1 ("k" is one of 1, 2, . . . , m and "l" is one of 1, 2, . . . , n). More specifically the set voltage is 170 V.
Contrary to the above case, in a display cell 131OP ("O" is one of 1, 2, . . . , m and other than "k" and "P" is one of 1, 2, . . . , n other than "l") in which writing discharge has occurred, as described above, since a positive wall charge is formed on the scanning electrode SO and a negative wall charge is formed on the sustaining electrode CP, a voltage to be produced by the positive and negative wall charges is superimposed on a voltage of the first positive sustaining pulse (called a "first sustaining pulse") to be applied to the scanning electrode SO in a forward direction. This causes a voltage exceeding a surface firing voltage to be applied to discharge space 126OP in the display cell 131OP and sustaining discharge occurs between the scanning electrode SO and the sustaining electrode CP. By this sustaining discharge, negative wall charges are accumulated on the scanning electrode SO and positive wall charges on the sustaining electrode CP, which reverses the accumulated state of wall charges.
When the application of the first sustaining pulse is completed, a voltage pulse to be applied to the scanning electrode SO from the sustaining driver 149 on the side where scanning operations are performed and a voltage pulse to be applied to the sustaining electrode CP from the sustaining driver 136 are reversed in phase and each of the phase-reversed voltage pulses (called a "second sustaining pulse") is applied to the corresponding scanning electrode SO and sustaining electrode CP. A voltage of negative wall charges accumulated on the scanning electrode SO and a voltage of positive wall charges accumulated on the sustaining electrode CP are superimposed on a voltage of the second sustaining pulse to be applied as above in a forward direction and, as in the case of the first sustaining pulse, wall charges having a polarity being reverse to that of a voltage of the first sustaining pulse, that is, positive wall charges are accumulated on the scanning electrode SO and negative wall charges on the sustaining electrode CP.
Even after the application of the second sustaining pulse has been terminated, since the application of the first sustaining pulse and the second sustaining pulse is repeated, discharge continues to occur between the scanning electrode SO and the sustaining electrode CP. That is, a potential difference produced by wall charges formed on the scanning electrode SO and the sustaining electrode CP by the X-th sustaining discharge is superimposed on a voltage of the "X+1st" sustaining pulse, which causes the sustaining discharge to be sustained.
By operating as above, light-emitting in the display cell 131OP continues. Light-emitting luminance in the display cell 131OP is determined by the number of times of sustaining the sustaining discharge. Moreover, by changing the number of sustaining pulses to be applied in each sub-field, gray levels in the display cell 131OP can be adjusted.
A method is disclosed in Japanese Patent Application Laid-open No. Hei 6-337654 in which, in an address-while-display (AWD) driving method in which scanning operations are performed while a sustaining pulse is being applied, after application of a scanning pulse, a pulse having a polarity being reverse to a scanning pulse is applied to an electrode to which a scanning pulse is not applied, out of two surface electrodes. Also, a method is disclosed in Japanese Patent Application Laid-open No. 2001-117532 in which pulse application time is provided between time for application of a scanning pulse and time for application of a subsequent pulse and, during the pulse application time, a pulse having a polarity being reverse to that of the scanning pulse is applied to a sustaining electrode.
In the conventional method for driving the address-display separated-type AC PDP performing such operations as above, when an image with high definition is to be displayed by increasing the number of scanning lines, the scanning period 3 is lengthened as the number of the scanning lines increases. If a frequency to be used in one field is fixed to be 60 Hz, a length of the sustaining period 4 corresponding to an increased length of the scanning period 3 is decreased. The decrease in the length of the sustaining period 4 causes lowering of light-emitting luminance which degrades a display characteristic.
An available countermeasure to avoid the above degradation includes a method by which the number of sub-fields is decreased and another method by which a width of a scanning pulse is decreased. However, the decrease in the number of sub-fields causes a decrease in the number of gray levels or occurrence of false contouring of moving images.
The decrease in a width of a scanning pulse presents the following problems. That is, as is apparent from above descriptions, in the conventional driving method, when application of a scanning pulse is terminated, a potential of the scanning electrode Si is boosted to become a voltage "Vbw", a potential difference between the scanning electrode Si and sustaining electrode Ci is reduced to be a voltage of "Vs−Vbw". This means that amounts of movements of space charges which are formed between the scanning electrode Si and sustaining electrode Ci at time of the application of the scanning pulse 6 and which produce wall charges on each of electrodes rapidly becomes small at the same time when the application of the scanning pulse 6 is terminated, which causes further formation of wall charges to be weakened.
That is, since time before the application of the scanning pulse is terminated after writing discharge has started is shortened, formation of wall charges sufficiently enough to let operations in the scanning period 3 shift to have sustaining discharge occur in the sustaining period 4 on the scanning electrode Si and sustaining electrode Ci becomes difficult.
In such the state in which sufficient wall charges are not formed on the scanning electrode Si and sustaining electrode Ci, even if the first sustaining pulse is applied when operations in the sustaining period 4 start and shift to sustaining discharge and even if a voltage of a wall charge formed by the writing discharge is superimposed on the voltage "Vs" of the first sustaining pulse, since the wall charges are not formed sufficiently as described above, a potential difference between the scanning electrode Si and sustaining electrode Ci does not reach a potential difference required for making sustaining discharge occur, that is, does not reach a surface firing voltage being a minimum voltage required for occurrence of surface discharge.
Therefore, unless sufficiently intense discharge occurs before operations start in the sustaining period and unless, when the first sustaining pulse is applied after the occurrence of the intense discharge, a wall charge having a polarity being reverse to that of the wall charge formed by the above discharge is formed on the scanning electrode Si and sustaining electrode Ci, operations do not shift to have sustaining discharge occur with reliability, thus causing a display cell not to be lit or a flicker to occur in displayed images.
To improve points described above, a voltage of a sustaining pulse or of a data pulse has to be boosted. This causes an increase in power consumption and/or use of an expensive driver that can withstand a high voltage, which leads to high costs.
In the address-while-display (AWD) driving method disclosed in Japanese Patent Application Laid-open No. Hei 6-337654 in which scanning operations are performed while a sustaining pulse is being applied, after the application of a scanning pulse, a pulse having a polarity being reverse to that of the scanning pulse is applied to an electrode, out of two surface electrodes, to which the scanning pulse has not been applied. However, simple application of this method to the address-display separated method does not produce a satisfactory effect. To obtain sufficient effects, optimization of a pulse voltage, a position of a pulse to be applied, and a width of the pulse is necessary.
In the method disclosed in Japanese Patent Application Laid-open No. 2001-117532, pulse application time is provided between time for application of a scanning pulse and time for application of a subsequent pulse and, during the pulse application time, a pulse having a polarity being reverse to that of the scanning pulse is applied to a sustaining electrode. Therefore, the pulse application time during which a pulse is applied to a sustaining electrode between time for application of a scanning pulse and time for application of a subsequent pulse is additionally required. As a result, this method enables the scanning pulse to be shortened, however, a scanning period cannot be shortened.

Method for driving address-display separated type AC plasma display panel and driving device using same


In a recording and reproducing system operable in an AV mode for recording and reproducing a plurality sets of video and audio signals, each set consisting of a combination of at least a video signal and an audio signal, an AV number is recorded together with the video and/or audio signals in each set, and all video and audio signals having the same AV number can be reproduced in combination.

This invention relates to a recording and reproducing system whose typical example is an electronic still camera, in which video signals and audio signals are recorded, in combination, on coaxial tracks on a magnetic disk. The present disclosure relates to the subject matter contained in Japanese patent application No. Hei. 2-42188 (filed on Feb. 22, 1990) which is expressly incorporated herein by reference in its entirety.
An electronic still camera is designed to record a video signal and an audio signal on a magnetic disk, with the video signal and the audio signal being recorded independently of each other in a normal mode and being recorded in combination in an AV mode. Therefore, the video signal and audio signal recorded in the normal mode are reproduced separately, and the video signal recorded in the AV mode is reproduced simultaneously when the corresponding audio signal is reproduced.
However, in the conventional electronic still camera, in the case where a single video track and a plurality of audio tracks corresponding to the video track are recorded in the AV mode, when it is required to reproduce the video and audio tracks by specifying one of these tracks, it is very difficult to determine which track number should be specified. Especially, in the case where a plurality of sets or pairs of video and audio tracks are recorded on the disk in the AV mode, the fear of confusing the operator will increase. Further, an audio signal and plural video signals cannot be recorded and reproduced in combination. Furthermore, plural audio signals and plural video signals cannot be recorded and reproduced in combination.

Recording and reproducing system in which audio and video signals are recorded in a plurality of sets


A pilot injection controller and a method of controlling pilot injection quantity enable the quantity of fuel pilot-injected fuel by an internal combustion engine fuel injection system of the type in which the fuel delivery stroke for pilot injection is fixed to be maintained substantially constant irrespective of engine speed by controlling prestroke such that the utilized portion of a cam is shifted to a lower delivery velocity region thereof with increasing engine speed, the principle involved being that the quantity of fuel pilot-injected by a fuel injection system is proportional to the actual plunger delivery velocity and the fact that since the actual delivery velocity is proportional to the product of the cam velocity constant and the cam rotational speed the actual delivery velocity can be maintained substantially constant by increasing the cam velocity constant in the low speed region and decreasing the cam velocity constant in the high speed region.

1. Field of the Invention
This invention relates to a pilot injection controller in an internal combustion fuel injection system and a method of controlling the quantity of pilot-injected fuel, more particularly to a pilot injection controller in a fuel injection system with a fixed pilot injection plunger delivery stroke wherein optimum quantity of pilot-injected fuel can be achieved over a wide range of engine speeds by controlling the plunger delivery velocity and to a method of controlling the quantity of pilot-injected fuel therewith.
2. Prior Art
Prior art engine fuel injection systems use a cam connected with the engine to reciprocate each plunger for delivering fuel to the associated combustion chamber. As taught by Japanese Patent Public Disclosure Sho 62-55436, for example, some fuel injection systems of this type reduce combustion noise and generation of oxides of nitrogen (NOx) by preceding the main fuel injection with a pilot fuel injection which injects a smaller quantity of fuel than the main fuel injection.
The desired quantity of pilot-injected fuel is, for example, generally about 5 mm.sup.3. In a fuel injection system in which the delivery stroke of the plunger for pilot injection has a fixed pilot injection delivery stroke, however, the quantity of pilot-injected fuel varies greatly with the speed of the engine or cam.
Specifically, the quantity of pilot-injected fuel in the low-speed region is zero or at any rate very small owing to the small delivery energy, while it becomes large in the high-speed region owing to the dynamic effect and/or the preflow effect, so that in extreme cases the pilot injection may continue into the main injection and make it impossible to achieve the purpose of the pilot injection.
In a fuel injection system in which the quantities of fuel injected in the main and pilot injections are both electronically controlled (as described in Japanese Patent Public Disclosure Hei 3-233142, for example), the quantity of pilot-injected fuel can be appropriately controlled by appropriately opening and closing a solenoid valve in response to the engine speed, cam speed and/or other operating conditions. On the negative side, however, the system becomes complex, large and expensive, while the desired rapid control cannot always be achieved in actual operation because of problems with the opening-closing response of the solenoid valve.
Although constituting a fuel injection system to enable mechanical instead of electronic control of the quantity of pilot-injected fuel would enable structural simplification and avoid cost increase, it would lead to problems particularly in the case of a fuel injection system of the type in which the fuel delivery stroke for pilot injection is fixed (cannot be varied at as desired). Specifically, since, as explained in the foregoing, the quantity of pilot-injected fuel varies with engine speed, it would become difficult to achieve a sufficient pilot injection quantity in the low speed region.
This invention was completed in the light of the foregoing problem and has as one object to provide a pilot injection controller in a fuel injection system which makes it possible to obtain a constant quantity of pilot-injected fuel over a wide range of engine speeds and a method of controlling the quantity of pilot-injected fuel therewith.
Another object of the invention is to provide a pilot injection controller in a fuel injection system which enables optimization of the quantity of pilot-injected fuel over a wide range in a fuel injection system of the type in which the fuel delivery stroke for pilot injection is fixed and a method of controlling the quantity of pilot-injected fuel therewith.
Another object of the invention is to provide a pilot injection controller in a fuel injection system which enables optimization of the quantity of pilot-injected fuel over a wide range by controlling the actual delivery velocity of a plunger to a fixed value and a method of controlling the quantity of pilot-injected fuel therewith.

Pilot injection controller in fuel injection system and method of controlling pilot injection quantity


Methods, ovens, and associated apparatus. Ovens and methods are adapted for maintaining the quality of a pre-cooked food product. Rapid temperature and/or relative humidity restoration may be used. Ovens may include a partition movable to vary sizes of oven cavities. Ovens may include removable interior panels. Humidification mechanisms are adapted for generating water vapor which may be used to maintain the quality of a pre-cooked food product.

Food holding ovens are used in the fast food service industry, for example, to hold pre-cooked food at a desired temperature for a period of holding time during which the quality of the food remains suitable for serving. If the food is not consumed within this time, it is generally discarded. Some such ovens have food holding compartments with open fronts and backs (i.e., no doors) to facilitate access to the compartments. Other ovens have holding compartments with doors, which allows the temperature and humidity conditions in the holding compartments to be more closely controlled to achieve longer periods of holding time. However, opening the door of a holding compartment to place food in a compartment and/or remove food from the compartment will disrupt the desired temperature and humidity conditions in the compartment, and prior art ovens are slow to regenerate the desired holding environment after the door is closed. As a result, the duration of effective holding time for the food is reduced.


A testing module is provided including a driving assembly, a positioning assembly and a testing head mechanism. The positioning assembly positions the driving assembly and the testing head mechanism therein. The positioning assembly includes a positioning member. The positioning member includes a base seat. The base seat defines a receiving cavity. The testing head mechanism includes a cushioning mechanism accommodated in the receiving cavity and driven by the driving assembly to move relative to the positioning assembly.

1. Technical Field
The present disclosure relates to testing modules, and particularly to a testing module for testing key buttons of portable electronic device.
2. Description of Related Art
Inputting devices for portable electronic devices (e.g., mobile phones) require to be repeatedly operated. Usual inputting devices such as keypads are provided with key buttons. Key buttons typically should be tested e.g., for proper contacting to the printed circuit board.
A typical testing apparatus includes a pressing block and a pneumatically-driven testing module. The pressing block press downwardly against the key buttons directly and rigidly (i.e., without using any buffering means) by the testing module. When done this way, the key buttons tend to be damaged.
Therefore, there is room for improvement within the art.

Testing module for testing key buttons of portable electronic device

Shenzhen Futaihong Precision Industry Co., Ltd.


A process for the continuous solvent-free and mastication-free production of self-adhesive compositions based on polyisobutylene with at least one active pharmaceutical substance in a continuously operating apparatus having a filling section and a compounding section, comprising the following steps:

The present invention relates to a process for the continuous production and coating of self-adhesive compositions based on polyisobutylene with at least one active pharmaceutical substance.
Fundamental to the profile of performance requirements of pressure sensitive adhesive systems and the pressure sensitive adhesive articles produced with them (such as patches, for example) are the two physical phenomena of adhesion and cohesion of the pressure sensitive adhesive layers. Adhesion is dealt with in the technical jargon using the terms instant bond strength (tack) and bond strength (peel strength) and describes by definition the terms xe2x80x9cself-adhesivexe2x80x9d, xe2x80x9cpressure sensitive adhesivexe2x80x9d and/or xe2x80x9cpressure sensitive adhesive tapesxe2x80x9d, i.e., permanent adhesive bonding under xe2x80x9cgentle pressurexe2x80x9d.
Especially in the case of pressure sensitive adhesives based on rubber, this property is obtained by mixing in tackifying resins (tackifiers) and plasticizers having relatively low molecular weights.
The second defining property of the pressure sensitive adhesives is their simple residue-free redetachability after use. This property is determined essentially by the high molecular mass rubber fractions as the elastomer component, which give the system, in the form of cohesion (internal strength), the required strength under shear stress, which is of particular significance for the use of the products under mechanical loads.
The performance of the pressure sensitive adhesive is, therefore, critically determined by the balanced proportion of adhesion properties and cohesion properties and by compatibility, homogeneity and stability of the blend of components with extremely high and relatively low average molecular weights, something which is relatively easy to achieve when the composition is produced in industry-standard mixers and kneading machines using solvents.
The advantage of foregoing the use of solvents lies essentially in the simplification of the coating process. The avoidance of flammable solvents does away with the need for the drier units, with their high energy consumption for the evaporation and recovery of the solvents, and with the need to use explosion-protected units. Hot-melt coating units are compact and permit much higher coating speeds. The technology is an environment-friendly one in which there are no solvent emissions. Furthermore, no unwanted solvent residues remain in the self-adhesive composition. This is the reason for the reduction in the allergenic potential of the product.
For the solvent-free compounding, the prior art makes use predominantly of block copolymers having polystyrene block fractions, or natural and/or synthetic rubbers.
Owing to the high molecular mass fractions of the rubber (with Mwxe2x89xa73*105 g/mol), solvent-free self-adhesive compositions cannot be processed by the hot-melt pressure sensitive adhesive technology, or else the rubbers used must be reduced in their molecular weight (broken down) severely before processing.
The deliberate industrial process of rubber breakdown under the combined action of shear stress, temperature and atmospheric oxygen is referred to in the technical literature as mastication and is generally carried out in the presence of chemical auxiliaries, which are known from the technical literature as masticating agents or peptizers, or, more rarely, as xe2x80x9cchemical plasticizing agentsxe2x80x9d. In rubber technology, the mastication step is necessary in order to make it easier to integrate the additives.
According to Rxc3x6mpp (Rxc3x6mpp Lexikon Chemiexe2x80x94Version 2.0, Stuttgart/New York: Georg Thieme Verlag 1999), mastication is a term used in rubber technology for the breaking down of long-chain rubber molecules in order to increase the plasticity and/or reduce the (Mooney) viscosity of rubbers. Mastication is carried out by treating, in particular, natural rubber in kneading apparatus or between rolls at very low temperatures in the presence of mastication aids (masticating auxiliaries). The high mechanical forces which act lead to a xe2x80x9ctearing apartxe2x80x9d of the rubber molecules, with the formation of macroradicals, whose recombination is prevented by reaction with atmospheric oxygen. Mastication aids such as aromatic or heterocyclic mercaptans and their zinc salts or disulfides accelerate the mastication process by promoting the formation of primary radicals. Activators such as metal (iron, copper, cobalt) salts of tetraazaporphyrins or phthalocyanines enable the mastication temperature to be lower. For the mastication of natural rubber, mastication aids are used in amounts of from about 0.1 to 0.5% by weight in the form of masterbatches, which facilitate a uniform distribution of this small amount of chemicals within the rubber composition.
Mastication must be clearly distinguished from the breakdown known as degradation which results in all of the standard solvent-free polymer technologies, such as compounding, conveying and coating in the melt.
Degradation is a collective term for various processes which change the appearance and properties of plastics. Degradation may be caused, for example, by chemical, thermal, oxidative, mechanical or biological influences or else by the effect of rays (such as (UV) light). Examples of consequences are oxidation, chain cleavages, depolymerization, crosslinking, and/or elimination of side groups of the polymers. The stability of polymers with respect to degradation may be increased by using additives, for example, by adding stabilizers such as antioxidants or light stabilizers.
A variety of routes to the solvent-free production and processing of rubber pressure sensitive adhesives have been described.
The patent CA 698 518 describes a process for achieving a composition by adding high proportions of plasticizer and/or simultaneously strong mastication of the rubber. Although this process may be used to obtain pressure sensitive adhesives having an extremely high tack, a user-compatible shear strength can be achieved only to a limited extent, even with a relatively high level of subsequent crosslinking, owing to the relatively high plasticizer content or else to the severe breakdown in molecular structure of the elastomer to a molecular weight average of Mwxe2x89xa61 million.
The use of polymer blends, where besides nonthermoplastic natural rubber use is also made of block copolymers, in a ratio of approximately 1:1, is essentially an unsatisfactory compromise solution, since it results neither in high shear strengths when the self-adhesive tapes are used at relatively high temperatures nor in significant improvements relative to the properties described in the patent.
The use of exclusively non-thermoplastic rubbers as the elastomer component in the formulation of pressure sensitive adhesives with the existing cost advantage possessed by, for example, natural rubbers over the standard commercial block copolymers, and the outstanding properties, especially the shear strength of natural rubber and of corresponding synthetic rubbers, is also set out at length in the patents WO 94 11 175 A1, WO 95 25 774 A1, WO 97 07 963 A1 and, correspondingly, U.S. Pat. No. 5,539,033 and U.S. Pat. No. 5,550,175.
In these cases, the additives customary in pressure sensitive adhesive technology, such as tackifier resins, plasticizers and fillers, are described.
The production process disclosed in each case is based on a twin-screw extruder which permits compounding to a homogeneous pressure sensitive adhesive blend with the chosen process regime, involving mastication of the rubber and subsequent gradual addition of the individual additives with an appropriate temperature regime.
The mastication step of the rubber, which precedes the actual production process, is described at length. It is necessary and characteristic of the process chosen, since with the technology chosen therein it is indispensable to the subsequent integration of the other components and to the extrudability of the blended composition. Also described is the feeding in of atmospheric oxygen, as recommended by R. Brzoskowski, J. L. and B. Kalvani in Kunststoffe 80 (8), (1990), p. 922 ff., in order to accelerate mastication of the rubber.
This procedure makes it absolutely necessary to practice the subsequent step of curing by electron beam crosslinking (EBC) and to use reactive substances as EBC promoters in order to achieve an effective crosslinking yield.
Both process steps are described in the abovementioned patents, but the EBC promoters chosen also tend toward unwanted chemical crosslinking reactions at elevated temperatures, which limits the use of certain tackifying resins.
The object of the present invention is to provide a process with which pressure-sensitive self-adhesive compositions based on polyisobutylene and comprising at least one active pharmaceutical ingredient can be produced continuously without solvent and, if desired, can be coated in-line without the need for property-impairing mastication of the polyisobutylene.
This object is achieved by a process as set out in the main claim. Claim 2 describes the process with minor adaptations. The dependent claims relate to advantageous developments of the processes.
The invention accordingly provides a process for the continuous solvent-free and mastication-free production of self-adhesive compositions based on polyisobutylene with at least one active pharmaceutical substance in a continuously operating apparatus having a filling section and a compounding section, comprising the following steps:
a) feeding an initial batch comprising granulated polyisobutylene, at least one release auxiliary and at least one active pharmaceutical substance into the filling section of the apparatus;
xe2x80x83if desired, feeding low molecular mass polyisobutylene, fillers, plasticizers, tackifiers and/or resins,
b) transferring the feed components of the self-adhesive composition from the filling section to the compounding section,
c) if desired, adding the components of the self-adhesive composition that have not been introduced in the filling section, such as low molecular mass polyisobutylene, fillers, plasticizers, tackifiers and/or resins, to the compounding section,
d) if desired, adding further pharmaceutical substances to the compounding section of the apparatus,
e) preparing a homogeneous self-adhesive composition in the compounding section, and
f) discharging the self-adhesive composition.
The invention additionally embraces a process for the continuous solvent-free and mastication-free production of self-adhesive compositions based on polyisobutylene with at least one active pharmaceutical substance in a continuously operating apparatus having a filling section and a compounding section, comprising the following steps:
a) feeding an initial batch comprising granulated polyisobutylene, at least one release auxiliary into the filling section of the apparatus; if desired, feeding low molecular mass polyisobutylene, fillers, plasticizers, tackifiers and/or resins,
b) transferring the feed components of the self-adhesive composition from the filling section to the compounding section,
c) adding at least one pharmaceutical substance to the compound section and, if desired, adding the components of the self-adhesive composition that have not been introduced in the filling section, such as low molecular mass polyisobutylene, fillers, plasticizers, tackifiers and/or resins, to the compounding section,
d) preparing a homogeneous self-adhesive composition in the compounding section, and
e) discharging the self-adhesive composition.
The addition of at least one active pharmaceutical substance to the compounding section, and the possibly necessary addition to the compound section of components of the self-adhesive composition which have not been introduced in the filling section, such as low molecular mass polyisobutylene, fillers, plasticizers, tackifiers and/or resins, may take place over the entire length of the compounding section. In particular, a plurality of metering points are possible, so that each individual component may be metered in specifically via a separate feed depending on the requirements of the process regime.
It has been found particularly advantageous to use a twin screw extruder having at least one metering port, preferably between two and seven, and at least one devolatilization aperture, as the continuously operating apparatus.
Moreover, the temperature in the apparatus should not exceed 150xc2x0 C., preferably not 140xc2x0 C., with particular preference not 130xc2x0 C., in order to rule out thermal damage to, in particular, the active substance or substances.
In one advantageous embodiment of the process, a melt pump or extruder is arranged between the apparatus and the coating device in order to convey the self-adhesive compositions.
In the second process step, which takes place advantageously in connection with the compounding step in the twin screw extruder, the self-adhesive composition prepared in accordance with the invention is coated in a solvent-free manner onto a backing in web form, onto a release film or onto a release paper, using an applicator unit. Coating may take place over the full area or else partially.
In order to obtain a defined, air-bubble-free application of composition to the web-form material, it is advantageous for the self-adhesive composition to be subjected to devolatilization before entering the coating unit, something which is particularly important when inert gases are used during the compounding process in the twin screw extruder. In accordance with the process of the present invention, devolatilization may take place under the influence of subatmospheric pressure or to the atmosphere, preferably in screw machines.
At the exit from the apparatus, the self-adhesive composition preferably has a temperature of less than 150xc2x0 C., more preferably less than 130xc2x0 C., with particular preference less than 110xc2x0 C.
Various processes are suitable for coating onto web-form materials. Solvent-free self-adhesive compositions may be coated by means of an extrusion die downstream of the twin screw extruder. For the pressure buildup for the die coating, single screw extruders and/or melt pumps are particularly preferred, so that the web-form backing materials may be coated with composition application rates with a very low breadth of fluctuation.
A further possibility for coating web-form backing materials with the active substance self-adhesive composition prepared in accordance with processes of the invention is the use of roll coating applicator units or multiroll coating calenders, consisting preferably of at least two coating rolls, the self-adhesive composition being formed to the desired thickness as it passes through one or more roll nips prior to transfer to the web-form material. This coating process is particularly preferred when coating with extrusion dies alone no longer provides the required accuracy in the amount of composition applied. Depending on the nature of the web-form backing material to be coated, coating may take place in a co-rotational or counter-rotational process.
Coating is possible on roller coating applicator units or multiroll coating calenders at temperatures below 150xc2x0 C., so that it is also possible to coat self-adhesive compositions which comprise thermally sensitive active substances. For the purpose of increased gas bubble freedom of the coated adhesive composition, it is possible to install a vacuum devolatilizer, for example, a vacuum chamber, a devolatilizing extruder, air knives or the like, between twin screw extruder and applicator unit.
In accordance with the process of the present invention, there is no property-impounding mastication of the polyisobutylene, since the addition of the liquid components is made shortly after the polyisobutylene feed. These liquid components may comprise both low molecular mass polyisobutylene, plasticizers and/or tackifiers, and resins which melt only during the compounding process under the action of shear energy and/or external heating. Owing to the presence of these liquid components, the extent of frictional energy is limited in such a way that it is possible to prevent the mastication of polyisobutylene and also high resulting compounding temperatures. In the individual process steps, however, degradation processes may occur, but do not permanently impair the properties of the self-adhesive composition.
The twin screw extruder should have one or, preferably, a plurality of separate temperature control or cooling circuits in order to permit a temperature regime which allows the use of thermally sensitive active pharmaceutical substances. In cases where this is unnecessary, the temperature control circuits may also be combined with one another in order to minimize the number of temperature control devices.
The process of the invention permits the preparation of self-adhesive compositions with active pharmaceutical substances and, especially in conjunction with a downstream coating unit, the production of self-adhesive articles which in turn are used to produce patches or bandages, while achieving particular cost advantages.
The process consists essentially of the steps set out already, which optionally may be conducted under an inert gas atmosphere in order to prevent oxidative polymer degradation.
In the compounding step, a composition comprising polyisobutylenes, one or more active pharmaceutical substances, and the required adjuvants such as low molecular mass polyisobutylene, fillers, plasticizers, tackifiers and/or resins, is produced without solvent preferably in a twin screw extruder, the composition having a final temperature of less than 150xc2x0 C., preferably less than 130xc2x0 C., with very particular preference less than 110xc2x0 C. The active pharmaceutical substances here may be added directly at the beginning of the process, but may alsoxe2x80x94depending on the sensitivity of the active substancexe2x80x94be introduced into the twin screw extruder only at a later point in time. The addition may be made in straight or dissolved form.
In accordance with the invention, the self-adhesive composition is based on polyisobutylene.
According to Rxc3x6mpp Lexikon Chemie (Version 2.0, Stuttgart/New York: Georg Thieme Verlag 1999) the term polyisobutenes or polyisobutylenes (PIB) is used to refer to the polymers, counted among the polyolefins, of the structure
which are prepared by cationic polymerization of isobutene. Standard commercial PIBs may be classified in 3 product categories:
oily liquids (molar mass: 300-3000 g/mol)
viscose tacky masses (molar mass: 40,000-120,000 g/mol)
rubberlike elastic masses (molar mass: 300,000-2,500,000 g/mol)
The different molar masses may be adjusted during the polymerization by using regulators (for example, 2,4,4-trimethyl-1-pentene, xe2x80x9cdiisobutenexe2x80x9d).
To modify the PIB properties, isobutene may be copolymerized with appropriate copolymers [for example, styrene and styrene derivatives, isoprene, indene, 1,3-butadiene, cyclopentadiene, etc.]. The copolymers which are of technical interest generally contain  greater than 90% isobutene.
The fraction of the high molecular mass granulated polyisobutylene is in particular between 5% by weight and 30% by weight, preferably between 10% by weight and 20% by weight.
The fraction of the low molecular mass polyisobutylene is in particular between 20% by weight and 60% by weight, preferably between 30% by weight and 50% by weight.
Suitable fillers are free-flowing bulk materials and also mixtures thereof, such as cellulose, silica, alginates and pectins, which are not soluble in the adhesive matrix. The filler fraction is in particular between 0% by weight and 60% by weight, preferably between 0% by weight and 40% by weight, with particular preference between 10% by weight and 40% by weight.
Tackifying resins which can be used are, without exception, all tackifier resins known to date and described in the literature. Representatives that may be mentioned include the rosins, their disproportionated, hydrogenated, polymerized and esterified derivatives and salts, the aliphatic and aromatic hydrocarbon resins, terpene resins and terpene-phenolic resins. Any desired combinations of these and other resins can be used in order to adjust the properties of the resultant adhesive composition in accordance with what is desired. Reference may be made expressly to the depiction of the state of knowledge in xe2x80x9cHandbook of Pressure Sensitive Adhesive Technologyxe2x80x9d by Donatas Satas (van Nostrand, 1989).
The resin fraction is in particular between 0% by weight and 50% by weight, preferably between 0% by weight and 40% by weight, with particular preference between 10% by weight and 40% by weight.
Suitable tackifiers are all known tackifying polymers, from the group, for example, of the polyisoprenes, polybutadienes and polyacrylates. The tackifier fraction is in particular between 0% by weight and 50% by weight, preferably between 0% by weight and 40% by weight, with particular preference between 5% by weight and 30% by weight.
Plasticizers which can be used are all known plasticizing substances and also pharmaceutical auxiliaries. They include, inter alia, the paraffinic and naphthenic oils, (functionalized) oligomers such as oligobutadienes and oligoisoprenes, liquid nitrile rubbers, liquid terpene resins, animal and vegetable oils and fats, fatty acid esters, phthalates, alcohols, and functionalized acrylates. The plasticizer fraction is in particular between 0% by weight and 30% by weight, preferably between 2% by weight and 20% by weight.
Active pharmaceutical substances are substances which in human or animal organisms are used to prevent, heal alleviate or detect diseases. The active pharmaceutical substances used may include those having both a systemic and a local activity.
Typical active substances used in accordance with the invention are the following:
aceclidine, amfetaminil, amfetamine, amyl nitrite, apophedrine, atabrine, alprostadil, azulene, arecoline, anethole, amylene hydrate, acetylcholine, acridine, adenosine triphosphoric acid, L-malic acid, alimemazine, allithiamine, allyl isothiocyanate, aminoethanol, apyzine, apiole, azatadine, alprenolol, ethinazone, benzoyl peroxide, benzyl alcohol, bisabolol, bisnorephedrine, butacetoluide, benactyzine, camphor, colecalciferol, chloral hydrate, clemastine, chlorobutanol, capsaicin, cyclopentamine, clobutinol, chamazulene, dimethocaine, codeine, chlorpromazine, quinine, chlorothymol, cyclophosphamide, cinchocaine, chlorambucil, chlorphenesin, diethylethane, divinylethane, dexchlopheniramine, dinoprostone, dixyrazine, ephedrine, ethosuximide, enallylpropymal, emylcamate, erythrol tetranitrate, emetine, enflurane, eucalyptol, etofenamate, ethylmorphine, fentanyl, fluanisone, guaiazulene, halothane, hyoscyamine, histamine, fencarbamide, hydroxycaine, hexylresorcinol, isoaminile citrate, isosorbide dinitrate, ibuprofen, iodine, iodoform, isoaminile, lidocaine, lopirine, levamisole, methadone, methyprylon, methylphenidate, mephenesin, methylephedrine, meclastine, methopromazine, mesuximide, nikethamide, norpseudoephedrine, menthol, methoxyfluran, methylpentinol, metixene, mesoprostol, oxytetracaine, oxyprenolol, oxyphenbutazone, oxyquinoline, pinene, prolintane, procyclidine, piperazine, pivazide, phensuximide, procaine, phenindamine, promethazine, pentetrazole, profenamine, perazine, phenol, pethidine, pilocarpine, prenylamine, phenoxybenzamine, Resochin, scopolamine, salicylic acid ester, sparteine, trichloroethylene, timolol, trifluperazine, tetracaine, trimipramine, tranylcypromine, trimethadione, tybamate, thymol, thioridazine, valproic acid and verapamil, and also other active substances familiar to the skilled worker that can be absorbed through the skin, including the mucous membranes. This list is of course not exhaustive.
The active substance fraction in the self-adhesive composition is preferably between 0.001% by weight and 60% by weight, more preferably between 0.001% by weight and 20% by weight, with particular preference between 0.001% by weight and 10% by weight.
Depending on the intended use, suitable web-form backing materials for the self-adhesive compositions processed and produced in accordance with the invention are all known backings, with or without appropriate chemical or physical surface pretreatment of the coating side, and also anti-adhesive physical treatment or coating of the reverse side. Mention may be made, for example, of creped and noncreped papers, polyethylene, polypropylene and mono- or biaxially oriented polypropylene films, polyester, PVC and other films, foam materials in web form, made from polyethylene and polyurethane, for example, wovens, knits and nonwovens.
Finally, the web-form material may be a material with an antiadhesive coating on both sides, such as a release paper or a release film. If desired, the coated backing material is lined with a further release film or a further release paper.
The thickness of the self-adhesive composition on the web-form material may be between 10 xcexcm and 2000 xcexcm, preferably between 100 82 m and 500 xcexcm.
The intention of the examples which follow is to describe the invention in more detail, without wishing thereby to restrict the invention.

Process for the continuous production and coating of self-adhesive compositions based on polyisobutylene with at least one active pharmaceutical substance


An SCR reactor (50) is disclosed which permits ready removal of a catalyst bed (58) from the SCR reactor and provides an effecting sealing mechanism between the catalyst bed (58) and the frame (52) of the SCR reactor. The frame is provided with side rails (54, 56) which have individual indentations spaced therealong. The catalyst bed is provided with wheels (60A, 60B, 60C) along its length which permit the catalyst bed to be rolled along the side rails until the catalyst bed is moved into its installed position whereupon the wheels descend into the indentations (62), causing the weight of the catalyst bed to form an effective seal between a downwardly face edge (64) on the catalyst bed and the frame (52).

SCR reactor technology is being used with increasing frequency to treat the exhaust gases from an industrial process, such as energy production, before the gas is released to the atmosphere. The SCR reactor process relies on the use of proprietary catalyst to treat the exhaust gas as the gas passes through the SCR reactor. Because the catalyst is an integral part of the chemical reaction, great effort is used to provide maximum exposure of the catalyst to the exhaust gas and to insure that all the exhaust gas comes into contact with sufficient catalyst for treatment.
The catalyst has a limited effective service life. The catalysts are typically held within catalyst beds which must be removed and replaced with beds containing new catalyst at regular intervals. Therefore, great attention must be paid to the design so that this exchange of catalyst bed can be undertaken quickly with a minimum of effort. A need exists for further advancement in this regard, while maintaining the fundamental requirement of forming an effective seal between the catalyst beds and the catalyst reactor to insure that all exhaust gas pass through the catalyst.