A sectional valve includes a working valve and a control valve, which controls the working valve. In order to permit a greater flexibility with respect to possible settings and/or use or operation by comparison to known solutions, it is proposed, for example, that the control valve have a control spring (34, 34′), which presses the anchor (5) onto the control valve seat (17), and against which the control coil (26) lifts the anchor (5) from the control valve seat (17), a permanent magnet (29), which in an actuation state is configured to hold the anchor (5) lifted from the control valve seat (17) by the core (35), and a magnet holder (28), in and/or on which the permanent magnet (29) is held in the actuation state, and which permits a distance from the permanent magnet (29), and/or that the control valve is configured to variably position the core (35) along a force generated by the control spring (34, 34′).

For example, solenoid valves, which use a permanent magnet, with which a piston or anchor of the valve is held in a predetermined position, are known from DE 103 24 091 A1, EP 0 340 625 B1, EP 0 710 790 B1 and WO 94/23435 A1.
The solenoid valves described in these documents all share in common that their structure only allows a slight flexibility in terms of possible settings, and virtually no flexibility with respect to their use or operation.
During the application of solenoid valves from DE 103 24 091 A1, EP 0 340 625 B1, EP 0 710 790 B1 and WO 94/23435 A1, for example, there is no way to manually open or manually close the valve, since an electrical pulse on a coil provided for this purpose must be generated for respectively moving the piston or anchor into a position in which the valve is closed, and/or a position in which the valve is open. Given a valve that in this way requires power or energy to be opened, operation is thus not possible in the event of a power or energy outage. The ramifications of a power or energy outage are especially critical in particular in the field of extinguishing technology.
In addition, the structural design determines the force to be applied by the coils to move the piston or anchor, and thus the minimum electrical current to be conducted by the coils. This is disadvantageous, in that limitations are placed on the possible actuation, making it harder to replace a valve with another valve having another current requirement. It is possible to provide a separate actuation for a respective valve that provides the necessary minimum current. However, this constitutes an additional outlay, which affects the costs of the valve on the one hand, and poses an additional vulnerability to failure on the other. Various models could be provided already while configuring the basic valve, which are geared toward the respective standard. However, this is associated with a diversification of the manufacturing process, which also leads to increased costs, especially since limits are still placed on application even given a range of standards.
In light of the above, the object of the present disclosure is to provide a valve for switching fluids, in particular a sectional valve for an extinguishing agent line, which by comparison to the known solutions has a greater flexibility with respect to possible settings and/or use or operation. The disclosure is also geared toward a corresponding extinguishing system and a method for controlling such a valve, in particular such a sectional valve, for an extinguishing agent line.
A sectional valve is here understood as a valve in an extinguishing agent line with which a portion of the extinguishing agent line in which pressurized extinguishing agent is present is separated from an unpressurized portion of the extinguishing agent line (that can also transition directly into an end of the extinguishing agent line). Extinguishing agents can be present in the unpressurized portion of the extinguishing agent line, wherein this portion can also be empty (e.g., filled with air).
A first aspect of the disclosure proposes a valve for switching fluids, in particular a sectional valve for an extinguishing agent line, with a control valve and a working valve, which is designed for pilot control by the control valve, with a throttle bore that establishes a first fluid connection between an inlet of the valve to be pressurized and a piston chamber of the working valve, and a working piston with a first end face opposite the piston chamber that is larger than a second end face opposite the inlet, wherein the control valve is configured to open and close a second fluid connection between the piston chamber and an outlet of the valve, wherein the control valve further has: a control valve seat, an anchor that closes the second fluid connection together with the control valve seat when pressed onto the control valve seat, a magnetizable core and a control coil configured to exert a magnetic force on the anchor, such that the control coil lifts the anchor from the control valve seat to an extent that the second fluid connection allows a greater flow than the first fluid connection, wherein the control valve has a) a control spring, which presses the anchor onto the control valve seat, and against which the control coil lifts the anchor from the control valve seat, a permanent magnet, which in an actuation state is configured to hold the anchor lifted from the control valve seat by means of the core, and a magnet holder, in and/or on which the permanent magnet is held in the actuation state, and which permits a distance from the permanent magnet, and/or b) a permanent magnet, which presses the anchor onto the control valve seat by means of the core, and against the retaining effect of which the control coil lifts the anchor from the control valve seat, a control spring, which in an actuation state is configured to hold the anchor lifted off of the control valve seat, and a magnet holder, in and/or on which the permanent magnet is held, and which allows a distance from the permanent magnet for a transition into the actuation state, and/or wherein the control valve is configured to variably position the core along a force generated by the control spring.
A further aspect of the disclosure proposes an extinguishing system with an extinguishing agent line and a valve according to the disclosure.
Another aspect of the disclosure proposes a method for controlling a valve for switching fluids, in particular a sectional valve for an extinguishing agent line, wherein the valve has a control valve and a working valve, which is configured for pilot control by the control valve, with a throttle bore that establishes a first fluid connection between an inlet of the valve to be pressurized and a piston chamber of the working valve, and a working piston with a first end face opposite the piston chamber that is larger than a second end face opposite the inlet, wherein the control valve further has: a control valve seat, an anchor that closes the second fluid connection between the piston chamber and an outlet of the valve together with the control valve seat when pressed onto the control valve seat, a magnetizable core and a control coil configured to exert a magnetic force on the anchor, wherein the control valve is used to open and close the second fluid connection, wherein the anchor is lifted from the control valve seat during the opening process to an extent that the second fluid connection allows a greater flow than the first fluid connection, wherein a) in an actuation state, the anchor lifted from the control valve seat against a control spring that presses the anchor onto the control valve seat is held by means of the core via a permanent magnet, wherein the permanent magnet in the actuation state is held in and/or on a magnet holder, wherein the permanent magnet is removed to end the actuation state, and/or b) before an actuation state, the anchor is pressed onto the control valve seat by means of the core via a permanent magnet, wherein the control coil is configured to lift the anchor from the control valve seat against a retaining effect of the permanent magnet, wherein the permanent magnet is held in and/or on a magnet holder, and the permanent magnet is removed for transitioning into the actuation state, wherein in the actuation state, the anchor lifted from the control valve seat is held by a control spring, and/or with a step of setting a force to be applied by the control coil to achieve the actuation state by variably positioning the core along a force generated by the control spring.
In the present conjunction, "pressing the anchor onto the control valve seat" is understood as brining the anchor and control valve seat into contact, such that the anchor and control valve seat together close the second fluid connection. The term "pressing" here relates to producing a sealing pressing force between the anchor and control valve seat, and must here not be construed as being limited only to arranging the anchor between the pressing element and the control valve seat, and as the force acting on the anchor being directed toward the control valve seat, since the compression force, and hence the desired seal, can also be achieved by pulling the anchor into the control valve seat, i.e., given a suitable arrangement where a force acts on the anchor that is directed away from the control valve seat (see FIG. 2 of EP 0 710 790 B1).
On the one hand, the disclosure is based on the knowledge that the ability to remove the permanent magnet from the valve (or its functional location on the valve) is associated with manually switching the valve. If the permanent magnet serves to hold the anchor in the actuation state (i.e., in a state in which the sectional valve was actuated and is open), this actuation state can be canceled by removing the permanent magnet, so that the valve closes. By contrast, if the permanent magnet keeps the valve closed, removing the permanent magnet can yield a triggering in an actuation state. Given a suitable structural design of the sectional valve, it is also possible to combine these variants with each other.
On the other hand, it was recognized that a variable positionability of the core relative to its penetration depth brings with it a variable lift of the anchor, which can be used to adjust the desired or required attraction force of the control coil, since the acting magnetic force of the coil depends on the relative position of the control coil and anchor.
The control spring here acts indirectly or directly between the core and anchor, wherein the function of the control valve in terms of opening and closing the second fluid connection is only associated with a movement of the anchor, wherein the core remains at least essentially in its (variably adjustable) position.
The valve according to the disclosure is preferably provided as a sectional valve for an extinguishing agent line, so that the sectional valve is preferably configured for a pressure of the extinguishing agent in the inlet ranging from 5 to 400 bar, particularly preferably ranging from 10 to 140 bar.
Removing the permanent magnet must not be understood to mean that the permanent magnet would thus necessarily have to be completely separated from the remaining valve. For removal purposes, it is enough that the permanent magnet be removed from its normal position, in which it acts on the core (and hence possibly indirectly on the anchor), to a point where the effect of the permanent magnet is practically eliminated or at least reduced to under a threshold that equates to an elimination. For example, if the permanent magnet holds the anchor via the core against the force of the control spring, removing the permanent magnet is to be understood as moving the permanent magnet away from the core until the force of the control springs exceeds the retaining force exerted by the magnet on the anchor. Even if the permanent magnet is completely removed from the magnet holder, the permanent magnet can still be coupled with the valve as such, for example by means of a loss prevention device.
In an embodiment of the disclosure, the control valve is configured to generate a releasing magnetic field, which counteracts a retaining effect of the permanent magnet, wherein the control coil and/or a releasing coil are provided for generating the releasing magnetic field.
The releasing magnetic field can have a force effect that acts on the anchor in a region spatially separate from the permanent magnet on the one hand, and also act to weaken the magnetic field of the permanent magnet on the other (i.e., overlap the magnetic field of the permanent magnet and possibly even extinguish it). In this way, the releasing magnetic field can be used to control the valve. It is here possible to also use the control coil for generating the releasing magnetic field, even given a reversed direction of flow.
In a configuration of the above embodiment, the releasing coil is provided in the magnet holder.
Given a releasing coil provided in the magnet holder, actuating (i.e., applying a current to) the releasing coil makes it possible to influence the effect of the permanent magnet, so that its effect is selectively eliminated or at least diminished to the extent necessary.
In another embodiment in which the valve has the permanent magnet and magnet holder, the magnet holder is removable.
It is not necessarily the case that the permanent magnet is removed out of or from the magnet holder or shifted inside of the magnet holder for removal purposes, since the magnet holder itself or at least a portion thereof can be removable in design. It is also possible both that the magnet holder can be removable, and that the magnet can be removed out of or from the magnet holder.
In another embodiment in which the variable positionability of the core is present, the core is screwed, latched, clamped, bonded and/or positioned with spacers into a guide bushing of the control valve.
The guide bushing of the control valve ensures a desired positioning of the core along a (longitudinal) axis defined by the force generated by the control spring, wherein the core can be positioned at various locations (continuously or incrementally) along this axis, for example to bring the lift of the anchor to a desired level in this way.
It can here be provided that, once a desired position has been set, the core is fixed in this position, for example by welding, bonding, soldering, wedging, countering or in some other suitable way.
In one configuration of the present embodiment, the anchor can be lifted off of the control valve seat by partially unscrewing or loosening the core from the guide bush.
If the variable positionability of the core is retained in the use state of the valve, the position of the anchor can also be influenced, in that the anchor is entrained by the core when being unscrewed or otherwise moved out of the guide bush, and thereby lifted off of the control valve seat. This provides another way of manually operating the valve.
In another configuration, the control valve is designed to screw and/or latch the core into the guide bushing with the permanent magnet held in and/or on the magnet holder, and subsequently lift the anchor held by the permanent magnet via the core from the control valve seat.
The combination of permanent magnet and core must be brought close enough to the anchor for the magnetic force to outweigh the force of the control spring. Given a variable positionability of the core, the core (together with the permanent magnet) can initially be brought closer to the anchor, so that the anchor adheres to the magnetized core, so that the anchor can then be taken along given a counter-movement of the core.
Also described here is a valve for switching fluids, in particular having the features in the present disclosure, with a working valve seat, into which the working piston can be pressed to separate the inlet and outlet, in particular by means of a working spring, wherein the working valve seat can be moved along the working direction of the piston (e.g., along a force generated by the working spring), wherein the working valve seat is configured to be exposed to a valve seat force and follow the movement of the working piston with the working piston pressed into the working valve seat, at least with the inlet pressurized and the working valve closed.
The valve described here preferably has features that are indicated and explained further above and with reference to the exemplary embodiments regarding the control valve. However, the features of the working valve enumerated here can be regarded as an independent disclosure taken separately, so that the valve described here could also be configured with a control valve or the like that does not have the features enumerated in the present disclosure.
Described here in particular is a valve for switching fluids, in particular a sectional valve for an extinguishing agent line, with: an inlet to be pressurized and an outlet, a working piston that can be moved along a working direction, and a working valve seat, wherein the working piston and working valve seat are together configured to open and close at least one direct fluid connection between the inlet and outlet, wherein the valve is configured at least to close the fluid connection for exposing the working piston to a working piston force, wherein the working valve seat can be moved along the working direction, and the valve is configured at least to close the fluid connection for exposing the working valve seat to a valve seat force, wherein the working valve seat is configured to follow a movement of the working piston with the working piston pressed into the working valve seat, with the fluid connection closed and the inlet pressurized.
During the operation of an extinguishing system, for example, pressure surges can arise in the extinguishing agent, i.e., brief pressure spikes or rises. In a conventional valve with piston and valve seat, it may come about that the piston is briefly lifted from the valve seat during such a pressure spike, so that the valve at least briefly becomes permeable.
It has been recognized that such a behavior with a movable working valve seat can be suppressed or even eliminated, since the working valve seat follows the piston moved by the pressure surge, thereby at least reducing the undesired permeability of the valve.
In a configuration of the valve described above, the valve seat force can be produced by a working valve spring and/or a difference in area between an end face of the working valve seat relative to the working piston, and an end face of the working valve seat relative to the inlet.
In particular using an area difference to produce or support the valve seat force is advantageous, since a proportionality or at least a proportional percentage of valve seat force to the height of the pressure spike is here obtained, so that the valve seat force also increases given a higher pressure spike, allowing the working valve seat to follow the piston more quickly. The working valve spring can be advantageous if the applied pressure is (still) very low, so as to ensure a minimum force. Let it be noted that the "and/or" linkage in the preceding paragraph must be understood to mean that emphasis is thereby placed on three variants, specifically, first, that the valve seat force is produced by a combination of the effects of the working valve spring and area difference, second, that the valve seat force is produced by the effects of the working valve spring (without or even against the influence of an area difference), and third, that the valve seat force is produced by the effect of the area difference (or the differential pressure resulting therefrom) (without or possibly against a spring effect). However, it is here also not precluded that a suitable configuration of the valve can also be switched between these variants without any fundamental conversion of the valve (i.e., in particular during operation), even if an embodiment without this type of switching would be advantageous given the simpler structural design.
In a valve described here with a movable working valve seat, the movability of the working valve seat can be limited by the lifting range, in which the valve remains closed, wherein the lifting range can be comprised in particular of a respective stop above and below the end faces of the working valve seat.
In the movable working valve cylinder, a seal is advantageously arranged between the upper end face of the working valve seat and the end face of the working piston directed toward the inlet.
Further described here is a valve for switching fluids, in particular having the features in the present disclosure, and/or having the features listed here with respect to the working valve seat that can move along the force produced by the working spring, wherein the valve has a fluid flow signal generator with a bushing and a signal piston guided in the bushing with an outlet end face, to which a pressure prevailing in the outlet of the valve is applied, wherein the signal piston is held in a resting position by a signal spring in an unpressurized state, and a) the signal piston extends outwardly through the bushing, so that a position of the signal piston is discernible from outside, and/or b) the valve has a detection means for detecting a predetermined deviation of the signal piston from the resting position.
The valve described here preferably has features that were indicated and explained further above, both in general and with reference to the exemplary embodiments relating to the control valve, as well as those described here in relation to the movable working valve seat. However, the features of the fluid flow signal generator enumerated here can be regarded as an independent disclosure taken separately, so that the fluid flow signal generator described here could also be used in a valve for switching fluids, in particular a sectional valve, or the like which does not have the features enumerated in the present disclosure.
Described here in particular is a valve for switching fluids, in particular a sectional valve for an extinguishing agent line, with an inlet and an outlet, wherein a fluid conducting connection between the inlet and outlet is closed with the valve in a resting state, wherein the valve has a fluid flow signal generator with a bushing and a signal piston guided in the bushing with an outlet end face, to which the pressure prevailing in the outlet of the valve is applied, wherein the signal piston is held in a resting position by a signal spring in an unpressurized state, and a) the signal piston extends outwardly through the bushing, so that a position of the signal piston is discernible from outside, and/or b) the valve has a detection means for detecting a predetermined deviation of the signal piston from the resting position.
Conventional valves for switching fluids, such as sectional valves, do not provide for any integrated state representation, so that taking a look just at the inlet, valve and outlet area does not make it clear right away whether an actuation state (i.e., an open valve) is present. One way of arriving at a state representation is to display the signal used for actuation or show that the control signal was received. However, this does not yet ensure that this state representation also reflects the actual state, since even given a received actuation signal, a mechanical malfunction in the valve itself can prevent the working valve from actually being open.
The signal piston is exposed to the pressure inside of the valve outlet, and can used to easily realize such a state representation.
Let it be noted that the aforementioned bushing need not necessarily be a component separate from the valve body or the like. While the term "bushing" does also encompass this type of separate component built into the valve body or the like, it is also already realized by an opening (e.g., bore) in the valve body or housing of the valve. In other words, in the case of such an opening or bore, the housing of the valve or the valve body itself can be regarded as the bushing.
In a configuration of the described valve, the predetermined deviation is detected by a closing and/or opening of a mechanical, electrical, magnetic and/or optical contact given at least the predetermined deviation of the signal piston from the resting position.
Possible detection means include any elements or units with which the predetermined deviation can be detected, such as in particular mechanical or electromechanical switches, electrical contacts (contact between which is closed or opened by the deviation), reed contacts, Hall probes or light barriers.
In another configuration of the above valve, the signal piston has a seal relative to the bushing, which is located between the outlet and signal spring and/or in an outer wall of the bushing.
If the outlet is sealed relative to the signal spring, the signal spring is not exposed to the extinguishing means (or another fluid that flows through the valve and/or is present in the outlet), with a(n alternative or additional) seal also being possible between the signal piston and the bushing in the outer wall of the bushing.
In another configuration of the above valve, the signal piston, in particular given an unpressurized outlet, can be moved through exposure to an outside force in the direction of the outlet and/or opposite this direction to check the function.
A corresponding actuation from outside, for example by a user wishing to check the functionality of the signal piston and then indirectly of the valve as well, makes it possible to pull out the signal piston and/or press it into the valve, so that any blockage or other operational impairment can be recognized.
In another configuration of the valve, signal pistons and signal springs are dimensioned in such a way that the signal piston comes to abut against the bushing given a predetermined pressure in the outlet.
On the one hand, the abutment of the signal piston against the bushing can be used as an indication that the predetermined pressure was reached or is present, wherein a corresponding marking or designation can enable an easier recognition of the abutment. Just as any intermediate position, the abutment itself can in turn be detected by the detection means as an example of a predetermined deviation of the signal piston from a resting position.
On the other hand, if a corresponding seal or the like is provided in the area of the abutment, the abutment can also be used to achieve an additional sealing effect that is required or would be desirable above the predetermined pressure.

Valve for switching fluids, extinguishing system and method


A surgical suture includes an elongated core having a first leg and a second leg, a first set of barbs projecting from the first leg of the core, and a second set of barbs projecting from the second leg of the core. The suture has a stop projecting from the core that is located between the first and second sets of barbs, and a braid surrounding the elongated core and the stop for strengthening the suture. The suture includes a pledget having first and second openings extending through the pledget, with the first leg extending through the first pledget opening, the second leg extending through the second pledget opening, and the stop extending between the first and second pledget openings.

1. Field of the Invention
The present invention generally relates to surgical sutures, and more specifically relates to sutures used for affixing prosthetic devices to tissue.
2. Description of the Related Art
Surgical sutures are used to close wounds and surgical incisions, and to repair damaged or severed muscles, vessels, and tissue. Typically, the suture is attached at one end to a needle, and the needle is drawn through tissue to form one or more loops holding the tissue together. The suture is subsequently tied off in one or more knots so that the tissue will remain drawn together.
Although sutures are very effective for closing wounds, there are a number of issues associated with using conventional sutures. Many of these issues are directly related to using knots to secure the sutures in place. If the knots are not tied properly, defects may arise including slippage, knot breakage, and re-opening of the wound.
In response to the obstacles associated with conventional sutures, barbed sutures have been developed. Unlike conventional sutures, barbed sutures have projecting barbs that allow the suture to be used to close wounds, approximate tissue, tighten tissue, and attach prosthetic devices—all without using knots. Fixing conventional sutures with knots requires the knots to be pushed down toward the tissue to assure proper tensioning and fixation of the sutures. In contrast, barbed sutures achieve proper tensioning and fixation by applying tension to the suture. For example, U.S. Pat. No. 5,931,855 discloses barbed sutures that are used for cosmetic procedures such as brow-lifts and face-lifts.
In some procedures, it is desirable to use barbed sutures to secure prosthetic devices such as bioprosthetic heart valves. For example, in certain embodiments of commonly assigned U.S. Patent Application Publication No. 2007/0005110, the disclosure of which is hereby incorporated by reference herein, braided barbed sutures are disposed in a heart valve sewing ring by first passing the sutures through an annulus and then passing the sutures through the valve sewing ring. First and second ends of the barbed suture may be passed through the openings of a pledget for securely seating the suture against the valve sewing ring. The pledget is typically positioned in a central region of the barbed suture, which is located between opposing sets of barbs. Approximately 12-20 sets of braided barbed sutures are used around the perimeter of the valve for securing the valve in place. The valve sewing ring is then parachuted down the sets of barbed sutures and seated in place within the annulus. After the sewing ring has been parachuted in a downward direction, the barbs prevent the sewing ring from being moved in the opposite, upward direction. The barbs hold the sewing ring in place without using knots.
In spite of the above advances, there remains a need for sutures, suture systems and suturing methods that more securely and reliably hold the sutures in place and minimize slippage of the sutures and/or the pledgets used in combination with the sutures. In addition, there remains a need for suture systems that simplify surgical procedures and minimize the likelihood of surgical error. There also remains a need for sutures that are able to more easily pass through tissue and sewing rings without causing damage.

Barbed sutures having pledget stoppers and methods therefor


A method of forming a glycosidic bond utilizing an activated thioglycoside is disclosed. The thioglycoside is activated by an N,N-dialkylsulfinamide and trifluoromethanesulfonic anhydride. The method allows the facile synthesis of disaccharides, oligosacchraides, and polysaccharides in solution or on a polymer support.

Carbohydrates play a central role in a wide variety of normal and abnormal biological recognition processes. For example, oligosaccharides and polysaccharides, as components of glycoproteins and glycolipids, are ubiquitous on cell surfaces and function as cell-surface markers for recognition by protein receptors. Although such carbohydrate-mediated interactions are important in biological events, an understanding of the structure-activity relationships (SAR) of carbohydrates has developed very slowly because of the difficulty of synthesizing well-defined oligosaccharides and polysaccharides for study.
For example, carbohydrates on cell surfaces have been implicated in chronic inflammation, in viral and bacterial infection, and in tumorigenesis and metastasis. Inhibiting interactions between cell surface carbohydrates and their protein receptors could provide an effective means of preventing or treating various diseases. Consequently, a great potential exists for, and a great amount of research is directed to, the use of synthetic oligosaccharides and polysaccharides as therapeutic agents.
One application of synthetic oligosaccharides is inhibition of cell adhesion. Thus, there is interest in synthetic carbohydrates that interfere with selectin and/or integrin binding, and, therefore, of use in the treatment of asthma, ARDS, reperfusion injury, multiple sclerosis, and various other chronic inflammatory diseases.
Synthetic carbohydrates also can be useful to inhibit bacterial adhesion to human tissue. Certain oligosaccharides and polysaccharides also can be useful to induce immune responses, for antibody production, e.g., as vaccines, or to induce disease states in research animals.
Despite such uses of synthetic oligosaccharides and polysaccharides in research and therapeutic applications, no universally applicable method exists for the synthesis of these complex molecules presently. Enzymatic methods have been developed that are effective in the regiospecific and stereospecific formation of glycosidic linkages, but the enzymes are relatively specific for particular substrates, and are not widely applicable to the variety of oligosaccharides and polysaccharides that must be synthesized. See, O. Karthaus et al. J. Chem. Soc. Perkin Trans., 1, 1851-1857 (1994), and M. Schuster et al., J. Amer. Chem. Soc., 116, 1135 (1994).
Oligosaccharide synthesis is not limited to an enzymatic method, and, therefore, carbohydrate synthesis has become a very active field of research. Other glycosylation reactions and strategies for carbohydrate synthesis have been developed. As a result, some relatively complex oligosaccharides have been synthesized, but to date no generally applicable "universal" synthetic method that can reliably generate glycosidic linkages with control of regiochemistry and stereochemistry exists.
Persons skilled in the art are aware that subtle changes in the structures of glycosyl donors and acceptors change the regiochemical and stereochemical outcomes, and the yields, of existing glycosylation reactions. Consequently, every oligosaccharide synthesis is a unique undertaking. The state of the art, therefore, does not permit the synthesis of large libraries of oligosaccharides for screening purposes
Combinatorial synthesis has been used to identify drug leads and elucidate structure-activity relationships in specific areas of drug discovery. Combinatorial methods of synthesizing peptides and nucleic acids on solid supports to provide combinatorial libraries of peptides and nucleic acids have been available for many years. But, combinatorial methods to synthesize carbohydrates on the solid phase only now are being developed. See Liang et al., Science, 274, pp. 1520-1522 (1996). The reliable preparation of a combinatorial oligosaccharide library requires reliable and consistently If high-yielding reactions, which give well-defined products from a variety of substrates under standardized reaction conditions.
Carbohydrates are notoriously difficult to synthesize, but research groups have made advances in simplifying and accelerating the synthetic process. For example, an automated solid-phase oligosaccharide synthesizer that facilitates preparation of carbohydrates has been developed (Science, 291, 1523 (2001)). The automated oligosaccharide synthesis allows production of oligosaccharides in about 1% of the time required using previous methods.
A comprehensive carbohydrate-based combinatorial capability requires an ability to link, attach, and modify sugars. However, the execution of such a comprehensive strategy is difficult because of the complexity of carbohydrate-based systems and the synthetic difficulties related to their construction and modification.
In addition, a simple monosaccharide contains multiple reactive sites and an anomeric center with difficult-to-control stereochemistry. Traditionally, a site selective reaction is controlled by complicated protecting group schemes. Further, the construction of multiple consecutive glycosidic linkages or glycosidic linkages to differing substrates typically relied upon different glycosylating reagents because of the lack of a single general glycosidic bond-forming reaction reliably applicable to a wide variety of substrates. Therefore, the success of a carbohydrate-based combinatorial program depends on effectively solving the unique chemical problems posed by carbohydrates.
The linking of monosaccharide units through a glycosidic bond is fundamental to the synthesis of oligosaccharides and various glycoconjugates. Therefore, the development of carbohydrate-based technology requires the construction of glycosidic bonds in the solid or liquid phase. The formation of glycosidic bonds is central to the field of glycobiology and to the preparation of a carbohydrate-based therapeutic or diagnostic agent.
Thioglycosides are among the most widely used glycosyl donors because of their ease of preparation and shelf stability. Thioglycosides also are compatible with numerous protection and deprotection synthetic steps, as well as being orthogonal to several other glycosidic bond-forming reactions, such as the trichloroacetimidate and glycosyl fluoride methods. See, P. J. Garegg, Carbohydr. Chem. Biochem., 52, pp. 179-266 (1997).
A thioglycoside requires activation to form a glycosidic bond. However, the stability that renders thioglycosides attractive as a donor, sufficiently reduces their reactivity in coupling reactions such that reaction times often are very long (e.g., up to ten days). Current methods of activating thioglycosides also suffer from one or more other disadvantages, such as unstable or unavailable activating agents, the need to oxidize the thioglycoside to the sulfoxide, poor stereoselectivity, and lack of generality. In addition, expensive reagents, which typically suffer from stability problems, are required for activation. Frequently, reagents used to activate thioglycosides are based on heavy (e.g., mercury) or precious (e.g., silver) metals, and pose problems of expense, environmental and toxicological concerns, and/or disposal.
Nonmetallic thiophiles of varying stability and activity currently in common use include dimethyl(methylthio)sulfonium triflate (DMTST), methylsulfenyl triflate (MeSOTf), benzeneselenyl triflate (PhSeOTf), iodonium dicollidine perchlorate (IDCP), and N-iodosuccinimide-trifluoromethane sulfonic acid (NIS/TfOH). Kahne's sulfoxide glycosylation method (D. Kahne et al., J. Am. Chem. Soc., 111, 6881-6882 (1989)) and related methods using glycosyl sulfimides (S. Cassel et al., Tetrahedron Letters, 39, 5175-5178 (1998)) are distinct from the mainstream methods because these methods require prior oxidation of the thioglycoside but, in doing so, permit the formation of highly reactive glycosylating species at low temperature.
Investigators, therefore, are searching for improved methods of activating thioglycosides, and forming of glycosidic bonds in general. One research group has developed a polymer-supported synthesis of oligosaccharides (O. J. Plante et al., Science, 291. pp. 1523-1527 (2001)). However, this technology does not permit the preparation of β-mannosides, and also utilizes a very unstable glycosyl phosphate and/or trichloroacetimidate.
The present invention provides a method of forming glycosidic bonds utilizing thioglycosides and an activating system that overcomes problems associated with prior methods of forming glycosidic bonds, and permits the automated synthesis of oligosaccharides and polysaccharides.

Method of forming glycosidic bonds from thioglycosides using an N,N-dialkylsulfinamide

The Board of Trustees of the University of Illinois


There is disclosed a disposable diaper including: an outer sheet facing outward; a liquid-permeable inner sheet facing a liquid receiving side; and an absorbent layer interposed between the outer sheet and the inner sheet, to form a front face portion to be applied to the abdomen of a wearer, an intermediate portion to be applied to the crotch, and a back face portion to be applied to the back side. A pattern sheet having a pattern and an area smaller than an area of the diaper, as viewed from the back face or the front face of the diaper, is adhered to the inner side of the outer sheet. The outer sheet allows the pattern to be observed therethrough.

1. Field of the Invention
The present invention relates to a disposable diaper and further to a disposable diaper having a pattern sheet allowing a pattern printed thereon to be observed only at a portion of the back face or front face of the diaper, and a method for manufacturing the same.
2. Description of the Related Art
In either the so-called xe2x80x9copen typexe2x80x9d disposable diaper for infants or babies or a disposable diaper which is formed in advance into the underpants shape, it is customary that a pattern such as the image of an animal or character appears on the outer sheet of the diaper.
The conventional method for attaching the pattern is generally done by printing a film to form the outer sheet (or back sheet) of the diaper in advance with continuous patterns or repeated patterns and by manufacturing the diapers of the outer sheet continuously by an automatic machine.
In the disclosure of Japanese Patent Laid-Open No. H3-90602 (90602/1991), on the other hand, a see-through outer sheet (or back sheet) is used and is jointed to another member on the inner side through a hot-melt type adhesive having a color. This hot-melt type adhesive is applied in a dotted shape to form a highly dense region of dots for expressing such an image or pattern as can be observed through the outer sheet.
The aforementioned method for manufacturing the diaper by using the film printed in advance with the pattern as the outer sheet is accompanied by the step of laying an absorbent layer and a liquid-permeable inner sheet (or top sheet) over the outer sheet having a band shape and by the subsequent step of separating individual diapers. This makes it substantially impossible for the completed disposable diaper to control what of its surface position the pattern or image is located at. It follows that the print on the outer sheet is limited to the continuous patterns or the repeated patterns, as described above, to restrict the degree of freedom for selecting the design of the pattern to appear on the surface. On the other hand, it is necessary to print the entire film for the outer sheet. This necessity raises the cost for manufacturing the outer sheet (or a film having the printed pattern). This cost is extremely raised if the pattern is to be expressed by the multicolor print, for example.
In the disclosure of Japanese Patent Laid-Open No. H3-90602 (90602/1991), moreover, a colored hot-melt type adhesive is applied to the outer sheet by using a roll coater to express the pattern by the dot application. This expression is unable not only to achieve a clear pattern but also to make a multicolor pattern. Moreover, although FIG. 1 of Japanese Patent Laid-Open No. H3-90602 (90602/1991) shows the pattern appearing only on one portion of the diaper, there arises a defect that a dislocation is liable to occur between the completed diaper and the pattern if the pattern is attached by the roll coater according to the aforementioned method.
The present invention has an object to provide a disposable diaper capable of attaching a pattern to only one portion of the diaper at a low cost and preventing any serious cost rise even where the pattern of a multicolor print is used, for example, and a method for manufacturing the disposable diaper.
According to the invention, there is provided a disposable diaper, comprising: an outer sheet facing outward; a liquid-permeable inner sheet facing a liquid receiving side; and an absorbent layer interposed between the outer sheet and the inner sheet, to form a front face portion to be applied to the abdomen of a wearer, an intermediate portion to be applied to the crotch, and a back face portion to be applied to the back side,
wherein a pattern sheet having a pattern and an area smaller than an area of the diaper, as viewed from the back face or the front face of the diaper, is adhered to the inner side of the outer sheet; and
wherein the outer sheet allows the pattern to be observed therethrough.
The disposable diaper of the invention may be the so-called xe2x80x9copen typexe2x80x9d or may be formed in advance into an underpants type.
The view of the disposable diaper, as taken from the back face or the front face, means that the diaper is flattened, while not being worn by a human body, to have its front face portion and back face portion in face-to-face contact with each other, and that this state is seen from the back side or the front side. Alternatively, the view means the projected shape taken from the back face or the front face by making the disposable diaper the same stereoscopic as it is worn by the human body. In short, it is sufficient to satisfy that the area to be occupied by the pattern sheet is smaller than the area (or the projected area) of the diaper either in the flattened state or in the stereoscopic state.
For example, it is preferred that the area to be occupied by the pattern sheet is 50% or less of the area of the diaper, as viewed from the back face or the front face of the diaper.
The pattern sheet may have any of polygonal, circular and elliptical shapes.
Preferably, the pattern sheet is an air- and moisture-permeable sheet on the surface of which the pattern is printed.
When the pattern sheet is exemplified by the air- and moisture-permeable sheet, as specified above, and when the outer sheet is also air- and moisture-permeable, the air- and moisture-permeating functions of the outer sheet are not obstructed by the pattern sheet adhered thereto. When the pattern sheet is so small as to have 50% or less of the area of the outer sheet, as viewed from the back face or the front face of the diaper, however, those functions of the outer sheet are hardly influenced and the entire diaper is prevented from being steamed stuffy, even if the pattern sheet has no air -and moisture-permeability.
For example: the outer sheet may be made of a nonwoven fabric; a liquid-impermeable sheet or a hydrophobic sheet may be disposed inside of the outer sheet; and the pattern sheet may be adhered between the outer sheet and the liquid-impermeable sheet or the hydrophobic sheet.
Alternatively, the outer sheet may be made of a film, and the pattern sheet may be adhered to the inner face of the film.
According to the invention, on the other hand, there is provided a method for manufacturing a disposable diaper, comprising: an outer sheet facing outward; a liquid-permeable inner sheet facing a liquid receiving side; and an absorbent layer interposed between the outer sheet and the inner sheet, to form a front face portion to be applied to the abdomen of a wearer, an intermediate portion to be applied to the crotch, and a back face portion to be applied to the back side,
the method comprising:
(a) the step of adhering a pattern sheet having a pattern and a smaller area than an outer sheet to a predetermined position on the inner face of the outer sheet which can be seen through;
(b) the step of placing an absorbent layer on the inner side of the outer sheet; and
(c) the step of laminating an inner sheet on the inner side of the absorbent layer, so that the pattern of the pattern sheet having an area smaller than an area of the diaper, as viewed from the back face or the front face of the diaper, can be seen through the outer sheet.
In this case, between the step (a) and the step (b), there can be further comprised the step of laying a liquid-impermeable sheet or a hydrophobic sheet for covering the inner side of the outer sheet, and sandwiching the pattern sheet between the outer sheet and the liquid-impermeable sheet or the hydrophobic sheet.
If the precision at the time of adhering the pattern sheet to the outer sheet is retained, according to the manufacture method of the invention, the pattern can be attached to the predetermined position of the diaper without dislocation. It is also possible to easily match the changes in the position and the size of the pattern.

Disposable diaper having pattern sheet, and method for manufacturing the same


A fuel composition comprising a major amount of hydrocarbons boiling in the gasoline or diesel range and about 2,050 to about 10,000 parts per million by weight of a hydrocarbyl-substituted polyoxyalkylene amine having the formula: ##STR1##. or a fuel-soluble salt thereof;. wherein R is a hydrocarbyl group having from about 1 to about 30 carbon atoms; PA1 R.sub.1 and R.sub.2 are each independently hydrogen or lower alkyl having about 1 to about 6 carbon atoms and each R.sub.1 and R.sub.2 is independently selected in each --O--CHR.sub.1 --CHR.sub.2 -- unit; PA1 A is amino, N-alkyl amino having about 1 to about 20 carbon atoms in the alkyl group, N,N-dialkyl amino having about 1 to about 20 carbon atoms in each alkyl group, or a polyamine moiety having about 2 to about 12 amine nitrogen atoms and about 2 to about 40 carbon atoms; and PA1 x is an integer from about 5 to about 100.. The fuel compositions of the present invention are useful for the prevention and control of engine deposits, particularly combustion chamber deposits.

1. Field of the Invention
This invention relates to the use of hydrocarbyl-substituted polyoxyalkylene amines in fuel compositions to prevent and control engine deposits.
2. Description of the Related Art
It is well known that automobile engines tend to form deposits on the surface of engine components, such as carburetor ports, throttle bodies, fuel injectors, intake ports, intake valves, and combustion chambers, due to the oxidation and polymerization of hydrocarbon fuel. These deposits, even when present in relatively minor amounts, often cause noticeable driveability problems, such as stalling and poor acceleration. Moreover, engine deposits can significantly increase an automobile's fuel consumption and production of exhaust pollutants. Therefore, the development of effective fuel detergents or "deposit control" additives to prevent or control such deposits is of considerable importance and numerous such materials are known in the art.
For example, aliphatic hydrocarbon-substituted phenols are known to reduce engine deposits when used in fuel compositions. U.S. Pat. No. 3,849,085, issued Nov. 19, 1974 to Kreuz et al., discloses a motor fuel composition comprising a mixture of hydrocarbons in the gasoline boiling range containing about 0.01 to about 0.25 volume percent of a high molecular weight aliphatic hydrocarbon-substituted phenol in which the aliphatic hydrocarbon radical has an average molecular weight in the range of about 500 to about 3,500. This patent teaches that gasoline compositions containing minor amounts of an aliphatic hydrocarbon-substituted phenol not only prevent or inhibit the formation of intake valve and port deposits in a gasoline engine, but also enhance the performance of the fuel composition in engines designed to operate at higher operating temperatures with a minimum of decomposition and deposit formation in the manifold of the engine.
Polyether amine fuel additives are also well known in the art for the prevention and control of engine deposits. These polyether additives have a polyoxyalkylene "backbone", i.e., the polyether portion of the molecule consists of repeating oxyalkylene units. U.S. Pat. No. 4,191,537, issued Mar. 4, 1980 to Lewis et al., for example, discloses a fuel composition comprising a major portion of hydrocarbons boiling in the gasoline range and from 30 to 2,000 ppm of a hydrocarbyl polyoxyalkylene aminocarbamate having a molecular weight from about 600 to 10,000, and at least one basic nitrogen atom. The hydrocarbyl polyoxyalkylene moiety is composed of oxyalkylene units having from 2 to 5 carbon atoms in each oxyalkylene unit. These fuel compositions are taught to maintain the cleanliness of intake systems without contributing to combustion chamber deposits.
Aromatic compounds containing a poly(oxyalkylene) moiety are also known in the art. For example, the above-mentioned U.S. Pat. No. 4,191,537, discloses alkylphenyl poly(oxyalkylene) polymers which are useful as intermediates in the preparation of alkylphenyl poly(oxyalkylene) aminocarbamates.
Similarly, U.S. Pat. No. 4,881,945, issued Nov. 21, 1989 to Buckley, discloses a fuel composition comprising a hydrocarbon boiling in the gasoline or diesel range and from about 30 to about 5,000 parts per million of a fuel soluble alkylphenyl polyoxyalkylene aminocarbamate having at least one basic nitrogen and an average molecular weight of about 800 to 6,000 and wherein the alkyl group contains at least 40 carbon atoms.
Also, U.S. Pat. No. 4,270,930, issued Jun. 2, 1981 to Campbell et al., discloses a fuel composition comprising a major amount of hydrocarbons boiling in the gasoline range and from 0.3 to 3 weight percent of a hydrocarbyl poly(oxyalkylene) aminocarbamate of molecular weight from about 600 to about 10,000 having at least one basic nitrogen atom, wherein the hydrocarbyl group contains from 1 to 30 carbon atoms.
U.S. Pat. No. 5,112,364, issued May 12, 1992 to Rath et al., discloses gasoline-engine fuels which contain from 10 to 2,000 parts per million by weight of a polyetheramine and/or a polyetheramine derivative, wherein the polyetheramine is prepared by reductive amination of a phenol-initiated or alkylphenol-initiated polyether alcohol with ammonia or a primary amine.
U.S. Pat. No. 5,660,601, issued Aug. 26, 1997 to Oppenlander et al., discloses fuels for gasoline engines containing from 10 to 2,000 mg per kg of fuel (i.e., 10 to 2,000 parts per million) of an alkyl-terminated polyetheramine, therein the alkyl group contains from 2 to 30 carbon atoms and the polyether moiety contains from 12 to 28 butylene oxide units. This patent further teaches that the polyetheramines are prepared by the reaction of an alcohol with butylene oxide, and subsequent amination with ammonia or an amine.
U.S. Pat. No. 4,332,595, issued Jun. 1, 1982 to Herbstman et al., discloses a gasoline detergent additive which is a hydrocarbyl-substituted polyoxypropylene diamine, wherein the hydrocarbyl substituent contains 8 to 18 carbon atoms. This patent further teaches that the additive is prepared by reductive amination of a hydrocarbyl-substituted polyoxypropylene alcohol with ammonia to give a polyoxypropylene amine, which is subsequently reacted with acrylonitrile to give the corresponding N-2-cyanoethyl derivative. Hydrogenation in the presence of ammonia then provides the desired hydrocarbyl-substituted polyoxypropylene N-3-aminopropyl amine.
U.S. Pat. No. 3,440,029, issued Apr. 22, 1969 to Little et al., discloses a gasoline anti-icing additive which is a hydrocarbyl-substituted polyoxyalkylene amine, wherein the hydrocarbyl substituent contains 8 to 24 carbon atoms. This patent teaches that the additive may be prepared by known processes wherein a hydroxy compound is condensed with an alkylene oxide or mixture of alkylene oxides and then the terminal amino group is attached by either reductive amination or by cyanoethylation followed by hydrogenation. Alternatively, the hydroxy compound or oxyalkylated derivative thereof may be reacted with bis(2-chloroethyl)ether and alkali to make a chlorine-terminated compound, which is then reacted with ammonia to produce the amine-terminated final product.
U.S. Pat. No. 4,247,301, issued Jan. 27, 1981 to Honnen, discloses hydrocarbyl-substituted poly(oxyalkylene) polyamines, wherein the hydrocarbyl group contains from 1 to 30 carbon atoms and the polyamine moiety contains from 2 to 12 amine nitrogen atoms and from 2 to 40 carbon atoms. This patent teaches that the additives may be prepared by the reaction of a suitable hydrocarbyl-terminated polyether alcohol with a halogenating agent such as HCl, thionyl chloride, or epichlorohydrin to form a polyether chloride, followed by reaction of the polyether chloride with a polyamine to form the desired poly(oxyalkylene) polyamine. This patent also teaches at Example 6 that the polyether chloride may be reacted with ammonia or dimethylamine to form the corresponding polyether amine or polyether dimethylamine.
U.S. Pat. No. 5,752,991 issued May 19, 1998 to Plavac, discloses fuel compositions containing from about 50 to about 2,500 parts per million by weight of a long chain alkylphenyl polyoxyalkylene amine, wherein the alkyl substituent on the phenyl ring has at least 40 carbon atoms.

Fuel compositions containing hydrocarbyl-substituted polyoxyalkylene amines


The present invention provides a method for preparing allylic alcohols by the palladium-catalyzed cross-coupling of vinylic epoxides and aryl halides, vinylic halides or vinylic triflates.

This invention was made with the support of NIH Grant No. GM40036. The U.S. Government has certain rights in this invention.
Synthetic methodology which allows for a rapid increase in molecular complexity is extremely valuable in organic chemistry, particularly when it accommodates considerable functionality. Presently, carbon-carbon bond formation catalyzed by transition metal complexes is used extensively in organic synthesis. For example, the cross-coupling of 3,4-epoxy-l-alkenes and stoichiometric amounts of organolithium, -boron, -copper, -mercury, -nickel, and -palladium compounds provides an important route to allylic alcohols (eq 1 ). ##STR1##
For example, see R. C. Larock, Comprehensive Organic Transformations; VCH Publishers, Inc., New York (1989) at pages 123-124, and J. A. Marshall et al., Chem. Rev., 89, 1503 (1989). R. C. Larock et al., in Tetrahedron Lett., 27, 2211 (1986) have reported one example of the analogous arylation of 4,5-epoxy-1-pentene employing stoichiometric amounts of an arylmercurial and either stoichiometric or catalytic amounts of palladium salts (eq 2). ##STR2##
More recently, R. C. Larock et al., in J. Org. Chem., 55, 6244 (1990) reported that palladium catalyzes the cross-coupling of aryl halides, but not vinylic halides, and olefinic epoxides in which the two functional groups are separated by anywhere from one to ten carbons (eq 3). ##STR3##
However, any attempt to extend this procedure to vinylic epoxides must circumvent the known propensity of such epoxides to react with palladium(O) to form .pi.-allylpalladium species which can undergo attack by various nucleophiles, including formate, or rearrange to dienols or unsaturated carbonyl compounds (eq 4). ##STR4##
If competitive, these pathways would circumvent the desired allylic alcohol formation. For examples of such side reactions, see B. M. Trost et al., J. Amer. Chem. Soc., 103, 5969 (1981); M. Oshima et al., J. Amer. Chem. Soc., 111, 6280 (1989); and M. Suzuki et al., J. Amer. Chem. Soc., 101, 1623 (1979). Therefore, a need exists for a method to prepare substituted allylic alcohols from vinylic epoxides and aryl or vinyl halides.

Iowa State University Research Foundation, Inc.


An electroluminescence device having an excellent moisture-resistant property is disclosed. Such an electroluminescence device comprises a light emitting layer inserted between an opposite electrode and a transparent electrode to form a multi-layered structure, said structure being airtightly sealed by a pair of protective sheets and said ELD being able to be fitted to an external apparatus by means of a metal fixture. The ELD is characterized in that a metal composite film is formed by inserting a metal foil between a pair of resin films and is used for one of the protective sheets for said opposite electrode. The composite film having a notch which is formed by removing part of the metal foil around a portion of the metal composite film prepared to accommodate the metal fixture.

The present invention relates an electroluminescence device and more particularly to an electroluminescence device using a highly moisture-resistant metal composite film as protective sheet for the opposite electrode.
The technological advancement in the field of electroluminescence devices (hereinafter referred to as ELDs) in recent years has made it possible to produce ELDs with relatively high luminosity and hence broadened the scope of application. Particularly, ELDs of dispersion type are attracting attention of interested parties as they have a wide variety of applications because of low cost, high luminosity and other advantages.
FIG. 3 of the accompanying drawings illustrates a sectional view of a conventional ELD and FIG. 4 is a partial enlarged view thereof, where reference numeral 1 denotes a transparent sheet, 2 a transparent electrode formed under said sheet 1 in the sense of the drawings, 3 a light emitting layer made of a phosphor-coated material and a dielectric material, 4 an opposite electrode made of a foil of metal such as aluminum, 5 a moisture absorbing layer having a highly hygroscopic property, 6 and 7 are protective sheets for protection of said transparent sheet 1, transparent electrode 2, light emitting layer 3, opposite electrode 4 moisture absorbing layer 5. Each of said transparent electrode 2 and opposite electrode 4 is provided with a lead terminal which is not shown in the drawings so that they can be electrically connected with an external power source and said light emitting layer 3 emits light when voltage is applied thereto.
Such a conventional ELD is normally sealed airtight by a pair of protective sheets 6 and 7, since if it is used in a moist environment, it can be degraded to significantly lose its luminosity and hence its durability as the phosphorcoated material in the ELD is decomposed quickly in such a moist environment. A synthetic resin film of ethylene trifluoride chloride or polyethylene is typically used for the protective sheet 6 of the transparent electrode, while a highly moisture-resistant metal composite film made of a pair of resin films 8, 8 of a material such as polyethylene terephtalate and a laminated metal 9 inserted therebetween is typically used as the protective sheet 7 for the opposite electrode 4. The peripheries of the two protective sheets 6 and 7 are bonded together by means of heat seal using a hot melt.
An ELD having a configuration as described above is typically used for a back light in a liquid crystal display apparatus. As shown in FIG. 5, ELD 20 is fitted to the back of the casing 22 incorporating a liquid crystal display 21 by utilizing a fixture 23 of the casing 22 and then the casing 22 is rigidly mounted on a wiring circuit substrate 24, while said liquid display 21 and ELD 20 are electrically connected with a drive circuit in said wiring circuit substrate 24 so that the light emitted from the light emitting layer 3 of the ELD 20 functions as a back light of the liquid crystal display 21 of a transmission type. Reference numeral 10 in FIG. 5 denotes a lead terminal for an external source to be connected with the ELD 20 and numeral 11 denotes a fitting bore to accommodate the fixture 23.
While a conventional ELD as described above and using a metal composite film 7 as a protection sheet for the opposite electrode 4 can be highly moisture-resistant because of the use of a metal laminate 9, it requires some electric insulating measures because it can undesirably affect circuits external to the ELD as the periphery of the metal foil 9 is exposed to the atmosphere and therefore can become electrically active. Referring to FIG. 5, if the casing 22 is made of a metal sheet with a view of giving it a function of grounding, noises picked up by the metal foil 9 can proceed to the grounding to interfere with the normal operation of the drive circuit because the metal foil 9 is connected with the metal fixture 23 within the fitting bore 11.
It is therefore an object of the present utility design to provide an ELD which uses a metal composite film for the protective sheet but effectively eliminates adverse effects of the metal film to external circuits.


A semiautomatic method for digital feature separation uses a trained sample selected by an operator using a software xe2x80x9ceye dropperxe2x80x9d tool or a similar region-of-interest tool to sample features of interest on a stored digital image of, for example, an electronic component such as pads, bumps or leads of the component. Pixels from the sampled features are analyzed and plotted based on their color hue and saturation values or gray scale intensity values. The range of such values is chosen by a user. A second digital image is then compared to the sampled feature data gathered by the xe2x80x9ceye dropperxe2x80x9d tool. If the color and intensity values of the pixels from the second digital image fall within a user defined acceptable absolute value range, then the locations and values of those pixels in the image are saved. Background or surrounding elements in the second digital image which do not fall within the acceptable value range are deleted and replaced with a code that makes these background or surrounding element locations appear as a graphic transparency. This process leaves only the features of interest in their original locations saved in the graphics memory surrounded by pixels that have been made video transparent. The resulting saved image which contains only the selected features is then laid over a live image such as that of a target substrate with corresponding features of interest. The operator then manually aligns the saved features from the component image over the corresponding features of the live image of the substrate to achieve component to substrate registration.

The present invention is relates to machine vision systems for relative positioning of a component and a substrate for accurate semi-automatic placement of the component at a selected location on the substrate. While the specific examples discussed herein relate largely to the electronics assembly industry, the components placed may be electronic, electro-optic, electro-mechanical, optical, mechanical, micro-electronic machine (MEMS) devices, biological material, and the like, and may be of any size.
Robotic assembly equipment is well known in the art. Such equipment includes, for example, pick and place (or placement) machines. A placement machine is a robotic instrument for picking up electronic and similar parts from component feeders and placing them at their assigned locations on a printed circuit board (PCB). Once all parts are placed, the PCB is placed in a reflow oven and solder paste disposed on the PCB melts or xe2x80x9creflowsxe2x80x9d forming permanent electrical connections between conductive pads on the PCB and electrical contacts, leads or xe2x80x9cpinsxe2x80x9d on the electrical components.
Occasionally there are problems with the permanent electrical connections. For example, two pads of the PCB may become inadvertently bridged by solder, forming a short; the component may be mis-located; the component may prove faulty; and the like. In these situations, it is often economically desirable to salvage the partially assembled PCB rather than to scrap it. In order to salvage the PCB, one must remove the faulty component, re-prepare the PCB surface, and place and solder a new component (or a cleaned component) in the correct position on the PCB. This process is termed xe2x80x9creworkxe2x80x9d. Reworking thus involves reflowing the solder of an identified target component (and not that of the entire PCB), removing the faulty component; cleaning and refluxing the PCB in the location where the component is to be mounted, reinstalling the component and reflowing the solder for the component.
In the past, most known rework systems operate almost entirely manually, i.e., a skilled operator, using an optical magnification system which views both the PCB top surface and the component bottom surface, manually aligns the PCB and the component for placement. Placement systems, on the other hand, typically employ machine vision systems to automate this process. However, most known systems utilize a pair of imagers. One imager views the top surface of the PCB to obtain PCB alignment information by imaging known reference points on the PCB (known in the art as xe2x80x9cfiducialsxe2x80x9d) and/or by imaging contact pads on the PCB, another imager views the component, its bottom and/or its sides, to determine component alignment information. Since skilled operators are relatively expensive to train and employ, it would be desirable to employ a semi-automatic machine vision solution to assist an operator in performing placement and rework functions placement and rework equipment.
A semiautomatic method for digital feature separation uses a trained sample selected by an operator using a software xe2x80x9ceye dropperxe2x80x9d tool or a similar region-of-interest tool to sample features of interest on a stored digital image of, for example, an electronic component such as pads, bumps or leads of the component. Pixels from the sampled features are analyzed and plotted based on their color hue and saturation values or gray scale intensity values. The range of such values is chosen by a user. A second digital image is then compared to the sampled feature data gathered by the xe2x80x9ceye dropperxe2x80x9d tool. If the color and intensity values of the pixels from the second digital image fall within a user defined acceptable absolute value range, then the locations and values of those pixels in the image are saved. Background or surrounding elements in the second digital image which do not fall within the acceptable value range are deleted and replaced with a code that makes these background or surrounding element locations appear as a graphic transparency. This process leaves only the features of interest in their original locations saved in the graphics memory surrounded by pixels that have been made video transparent. The resulting saved image which contains only the selected features is then laid over a live image such as that of a target substrate with corresponding features of interest. The operator then manually aligns the saved features from the component image over the corresponding features of the live image of the substrate to achieve component to substrate registration.


Maximum throughput of a wet process phosphoric acid plant at a fixed recovery can be obtained by controlling the filter feed to give a desired specific gravity of the filtrate from the last washing of the gypsum cake. The filtrate from the last washing of the gypsum cake also is called the first pass filtrate. The specific gravity of this first pass filtrate provides an indication of the overall filter efficiency and the loss of water-soluble phosphoric acid to the gypsum waste stream. The specific gravity of the first pass filtrate is controlled by adjusting the rate at which product slurry from the attack tank is fed to the filter. This product slurry feed rate is affected by the mechanical performance of the filter and the filterability of the gypsum crystals, which, in turn, is affected by operating conditions in the attack tank. Therefore, the feed rates of phosphate rock, sulfuric acid, and water, are controlled to produce the desired attack tank operating conditions and to maintain attack tank level. Each of the primary processing steps, i.e., operation of the attack tank and operation of the filter, is controlled to maximize plant efficiency. By minimizing phosphoric acid loss and optimizing operation of the attack tank in accordance with the invention, plant efficiency is maximized.

1. Field of the Invention
The present invention generally relates to an automatic control system for controlling a chemical process in order to maximize efficiency. More particularly, the invention relates to an automatic control system for controlling the operation of a phosphoric acid recovery plant in order to maintain constant efficiency.
Phosphoric acid (H.sub.3 PO.sub.4) is an important intermediate chemical product. It is used primarily by the fertilizer industry, but also is useful in a number of other areas such as in detergents, water treatment, and food products.
2. Description of Related Art
The most common method for producing phosphoric acid is known in the art as the "wet process." Using the wet process, phosphate rock, which comprises calcium and phosphorus, typically in the form Ca.sub.3 PO.sub.4, together with a number of impurities, is mined, beneficiated, and comminuted. Typically, ball mills or rod mills are used to obtain the desired size distribution. Grinding can be carried out by a wet or dry process; wet processing is typical. The ground rock then is fed, typically as an aqueous slurry, to a reactor, or "attack tank", and reacted with sulfuric acid. The process is represented by the following equation: EQU Ca.sub.3 (PO.sub.4).sub.2 +3 H.sub.2 SO.sub.4 +6 H.sub.2 O.fwdarw.2 H.sub.3 PO.sub.4 +3 CaSO.sub.4 .multidot.2 H.sub.2 O (A)
The phosphoric acid thus produced remains in aqueous solution; calcium sulfate, commonly referred to as gypsum, is a crystalline solid under reaction conditions. A simplified flow diagram of a wet process phosacid plant, including sulfuric acid manufacture, is illustrated in FIG. 1.
Although phosphoric acid is represented as H.sub.3 PO.sub.4, plant output most often is measured in tons of P.sub.2 O.sub.5, or phosphorous pentoxide. Approximately 4 tons of 30% phosphoric acid aqueous solution is equivalent to about 1 ton of P.sub.2 O.sub.5. It also is common in the trade to use the terms "phosphorous pentoxide" and "phosphoric acid" interchangeably when referring to plant output. "Phosacid" is a short form for phosphoric acid, typically in aqueous solution.
The operator of a phosphoric acid plant typically seeks to maximize the production of phosphoric acid from the limited amount of phosphate rock, thus minimizing any potential losses of phosphoric acid. To minimize cost, the operator must maximize overall plant efficiency. An important factor influencing the efficiency of a phosphoric acid plant is the amount of free or excess sulfate (SO.sub.4.sup.=, measured as weight percent of excess sulfate) in the reactor or attack tank. The amount of excess sulfate constitutes the amount of sulfate not reacted with calcium or in the form of CaSO.sub.4. On this basis, "excess sulfate" may have either a positive or a negative value (positive representing an excess of sulfate, and negative representing a deficiency of sulfate).
The reaction shown in Equation A produces two chemical products: phosphoric acid and calcium sulfate crystals (gypsum--a co-product). A properly operating phosphoric acid plant results in high P.sub.2 O.sub.5 recovery from the attack tank slurry and the formation of calcium sulfate crystals that contain little unreacted phosphate and have a shape, size, and porosity affording easy separation from the liquid by filtration. Level of excess sulfate is one of the most important factors governing crystallization quality.
There are primarily three types of P.sub.2 O.sub.5 losses that may occur in a phosphoric acid process. First are lattice losses or co-crystallization losses which occur due to the precipitation or co-crystallization of P.sub.2 O.sub.5 with the calcium sulfate. Lattice losses tend to increase as the amount of excess sulfate in the reactor is decreased. Second are coated rock losses which are due to an over-vigorous calcium sulfate (gypsum) crystallization. Such a crystallization causes phosphate rock particles to be covered by a gypsum layer, thus shielding the particles from further attack (reaction) by the sulfuric acid before the particles can completely react. Any phosphate rock particles that become coated with gypsum constitute a loss of P.sub.2 O.sub.5 production because the unreacted phosphate in the particle is filtered out of the phosphoric acid solution together with the other solid matter (primarily gypsum) in the tank slurry. Coated rock losses increase as the excess sulfate in the attack tank increases. Coated rock losses also may vary to some extent with the quality and with the fineness of the phosphate rock particles (rock quality is usually measured as a grade (a numerical value) in units of bone phosphate of lime (BPL)). Third are acid losses which occur due to inadequate filtration, i.e., leaving phosphoric acid solution in the filtrate. Gypsum crystal size, and thus filtration characteristics, is determined primarily by the variability in the excess sulfate. In a properly operated phosphoric acid plant, lattice losses and coated rock losses usually account for a majority of the acid losses encountered.
The recovery of P.sub.2 O.sub.5 is strongly dependent on the amount of excess sulfate in the reactor. The optimum operating point (target) for excess sulfate varies from plant to plant, and may vary with feed rate. Therefore, the optimum amount of excess sulfate for a particular operation typically is determined by periodic efficiency tests. To maximize production of P.sub.2 O.sub.5 in the reactor, the amount of excess sulfate in the reactor should be maintained as close as possible to this predetermined optimum (target) operating point. The determination of the optimum point of operation for a particular facility is well within the skill of the phosphoric acid process control art.
Another important factor that influences the efficiency of a phosphoric acid plant is operation of the filter. The reactor effluent, which comprises phosphoric acid solution and gypsum, is sent to a filtration unit wherein the solid gypsum is separated from the solution. The gypsum forms a filter cake and the filtrate comprises phosphoric acid solution. The filtrate is further treated before shipment.
The filter cake is washed with water to recover phosphorous values. Typically, a two or three-stage counter-current washing is utilized. Process water, which contains essentially no phosphorous values, is used to wash the gypsum cake a final time before the cake is removed as a by-product. In a three-stage system, the wash water, which contains some phosphoric acid, then is used in the penultimate washing, from which additional phosacid is recovered. In a third stage, the gypsum cake just separated from product acid is washed with the solution from the second washing. A portion of the solution from this third washing is introduced to the attack tank. This stream typically is known as an `acid-recycle stream`, as `return acid`, or simply as `return`.
Reactor and filtration operating parameters should be closely controlled to ensure maximum recovery of phosphoric acid from these units. Maximum recovery of phosphoric acid does not necessarily correlate with maximum concentration of phosacid in the reactor or the maximum concentration of phosacid in the product filtrate stream. Rather, the maximum recovery of product is obtained by maintaining an optimum concentration of phosacid in the reactor.
As set forth in Equation A above, water and sulfuric acid are fed to an attack tank along with phosphate ore. Typically, the ore is fed in the form of an aqueous slurry, and acid solution is recycled from the cake washings. It is typical to add a stoichiometric excess of water.
Water may be added by way of various process streams, including the feed phosphate ore ("rock") stream, the acid recycle stream from the filter, or a raw water feed stream. Water required to provide the stoichiometric quantity of water in accordance with the reaction set forth in Equation A may be added by way of any one of these streams. It is common in the trade to add the water to the attack tank by way of the return acid from the filter unit. However, an operator must take care not to add water to the filter in a quantity that will oversaturate the gypsum filter cake. As skilled practitioners recognize, it is not desirable for the moisture content of the filter cake to be excessively high because water remaining in the cake effects the water balance in the attack tank. It is desirable to maintain an overall water balance on the attack tank and filter to maintain the stoichiometric relationship set forth in Equation A in the attack tank while at the same time maintaining the efficiency of the filter unit and the moisture content of the filter cake.
Typically, in manual operation of a phosacid attack tank and filter, an operator would vary the amount of water added to the filter by visual inspection of the moisture content of the filter cake discharged and the knowledge of concentration of phosacid in the attack tank. For example, low phosacid concentration decreases cake discharge moisture content. As a consequence of the low phosacid concentration, the operator would decrease the amount of water added to the filtration unit. This decreases the rate at which water is added to the filter, and thus, less water will be added to the attack tank by way of the return acid. The lower quantity of return acid causes the phosacid concentration in the attack tank to increase.
As the phosacid concentration in the attack tank increases, the operator would add water to the filter in an attempt to bring the concentration of phosacid in the attack tank to its optimum value. However, this additional water would cause the moisture content of the gypsum filter cake to increase, and still more water would have to be added to the filter to rinse the filter cake. Under these conditions, the ability of the filter to accept more water would be marginal at best, because the gypsum crystals would be affected by the acid concentration. Also, as the concentration of phosacid in the attack tank increases, the viscosity of the reaction effluent increases, and the phosacid tends to adhere more easily to the gypsum crystals. The additional acid content of the slurry leaving the attack tank therefore causes the filterability of the gypsum filter cake to decrease and further reduces the efficiency of the filter. Thus, production rates of phosacid would decrease even though the concentration of phosacid in the attack tank was high.
Thus, keeping the phosacid concentration in the attack tank essentially constant is desirable to maximize phosphoric acid yield. Because the concentration of the phosphate ore fed to the attack tank is constantly changing, maintenance of the concentration of phosacid in the attack tank is difficult. Also, as described above, the sulfate and phosphoric acid concentrations in the attack tank influence the growth and type of calcium sulfate crystals formed in the attack tank. Thus, there is a need to control the operating conditions in the attack tank and filtration unit to ensure maximum yield of phosphoric acid.
Many problems may arise when attempting to maintain the excess sulfate in the reactor at the predetermined optimum point. If, for example, the optimum operating point was found to be zero percent excess sulfate, then the amount of sulfate desired in the reactor is that amount that allows a complete reaction of all phosphate and results in no (zero percent) excess sulfate present. The amount or flow rate of sulfuric acid necessary to achieve this optimum operating point will based on several factors including, inter alia, (1) the mass flow rate of the rock (usually measured in tons/hour), (ii) the quality or grade of the rock (CaO content), (iii) rock fineness, and (iv) reactor temperature. Therefore, the flow rate of sulfuric acid which is fed into the reactor (attack tank) required to achieve the optimum operating point (sulfuric acid demand) will vary with changes in rock mass flow rates, rock qualities, and fineness of incoming rock.
The quality or grade of the rock is determined by the calcium concentration and the type and amount of impurities in the rock. The fineness of the rock is determined by the rock itself and the process and equipment used to grind the rock. The mass flow rate of the rock, which may be considered to be the operating rate or speed of the plant, can be measured using a magnetic flow meter (if rock is fed as slurry) to determine volume flow of rock per unit time, and a nuclear density meter to measure the density of the rock slurry. Using these two values, the mass flow rate of the rock (tons/hour) may be calculated. For each rock type (including fineness, quality, etc.) there exists some demand of sulfuric acid (S) per ton of rock (R), which may be represented as the ratio S/R, which produces the desired level of excess sulfate in the reactor. This may be referred to as the desired S/R ratio.
The excess sulfate level in the reactor may be tested manually using well known laboratory methods, such as by precipitation of sulfate as barium sulfate and by measuring turbidity. The acid flow rate and the rock mass flow rate must be monitored and adjusted to maintain the excess sulfate level in the reactor equal to this predetermined level. For example, in one approach, the rock mass flow rate may be held approximately constant and the flow rate of the sulfuric acid adjusted to maintain the desired S/R ratio.
However, several additional problems exist which often hinder attempts to run the plant at this optimum operating point. First, the quality and fineness of the incoming rock are constantly changing because the quality of the rock and type of impurities in the rock vary widely among different ore sites, and even at the same site. Thus, the desired S/R ratio must frequently be updated in order to maintain the reactor at the optimum level of excess sulfate. Unexpected difficulties such as mechanical problems (i.e., broken pumps, stuck valves, and the like) often prevent maintaining the flow rates at a known constant level, and may cause the excess sulfate level in the reactor to change drastically before any malfunction is detected. Even if the sulfuric acid flow rate is properly adjusted for the particular incoming rock, the excess sulfate already present in the reactor may not be correct. Therefore, an additional adjustment in the sulfuric acid flow rate must be made to correct for any sulfate excess or deficiency already in the reactor. In addition, after an adjustment in the sulfuric acid flow rate has been made, there is an unavoidable lag time before the excess sulfate level in the reactor changes in response to the new acid flow rate.
Skilled practitioners also recognize that factors affect the ability to maintain the phosacid concentration in the attack tank at the optimum concentration. As described above, the concentration of phosphate ore in the rock fed to the attack tank constantly changes. To maintain the concentration of phosacid in the attack tank at its optimum value, the amount of water added to the attack tank must be adjusted to maintain at least the stoichiometry of Equation A above. The water addition rate must also be adjusted to compensate for differences in reaction rate caused by differences in fineness of the rock. Failure to consider fineness and its effect on reaction rate may cause the concentration of phosacid in the attack tank solution to change even though the mass flow rate of feed rock is constant.
Filterability of the reaction slurry (attack tank effluent) also affects product recovery. Because the amount of phosphate fed to the attack tank is not constant, the amount of sulfuric acid needed to effect the reaction set forth in Equation A above also changes. The amounts of product and by-product produced thus are constantly changing, and these changes affect the chemical makeup of the filter cake. Thus, rinse water may be required at the filtration unit to further rinse the filter cake and remove the phosacid entrained therein, but the additional water may not be necessary at the attack tank. Further difficulties arise when unexpected mechanical problems affect the flow rates of attack tank feed and effluent streams, and may cause the phosacid concentration in the attack tank to worsen drastically before these problems are detected.
Although plant efficiency of a phosacid plant is strongly related to the efficiency of the filtration step, control of filter operation, or of the attack tank, does not provide control of overall plant efficiency. For example, U.S. Pat. No. 3,104,946 discloses a method for controlling a wet process plant by monitoring the free sulfuric acid (sulfate) content in the attack tank by adjusting the acid-to-rock feed ratio to compensate for the sulfuric acid (sulfate) content of the recycle stream. In SU 597,632 is disclosed a method for controlling the sulfuric acid dilution process by regulating the flow rates of concentrated sulfuric acid, monohydrate, and water to maintain a constant stoichiometric ratio of diluted sulfuric acid and of the monohydrate. Plant efficiency is not considered in such control schemes.
The aims of other control schemes, such as that disclosed in U.S. Pat. No. 4,777,027, are not plant efficiency, but rather energy efficiency or reduced capital requirements. Indeed, the method disclosed in U.S. Pat. No. 4,777,027, is directed, inter alia, to production of calcium sulfate solids in a particular form (e.g., hemihydrate, dihydrate) desired for subsequent use. While maintaining conditions appropriate for a wet process producing phosphoric acid, operating conditions (in particular, reaction temperatures and flow rates of mixtures circulating around the reactors) are adjusted to produce the desired form of calcium sulfate at a concentration which achieves a desired phosphoric acid concentration.
One method said to provide efficient control over a wet process plant is disclosed in SU 1,411,276 (abstract). In accordance with that method, one obtains a material balance on the liquid streams to and from the filter and calculates the ratio of liquid to solid in the attack tank effluent. The rate at which water is added to the attack tank also is determined. The ratios of the flow rates of raw material to the flow rate of recycle and of liquid material to solid material in the attack tank are computed. The concentration of phosphoric acid in the liquid phase of the attack tank and the level in the attack tank are kept at desired operating points by adjusting the recycle rate. The ratio of liquid phase to solid phase in the attack tank also is controlled by adjusting recycle rate.
Methods of controlling reactions to produce constant production rate of a desired product, such as that disclosed in U.S. Pat. No. 3,130,187, do not maintain plant efficiency. Similarly, control schemes for reactions requiring a plurality of feed stocks, such as the scheme disclosed in U.S. Pat. No. 4,332,590, which control relative reactant concentration ratios and total feedrate to achieve a desired total production by maintaining a desired reactant concentration, do not achieve constant efficiency.
In accordance with the method of U.S. Pat. No. 4,332,590, the flow rates of all materials fed to and removed from the reactor, including any recycle streams, are manipulated to control reactor residence time. Further, the temperatures of streams fed into the reactor are controlled to achieve a desired conversion rate. The aim of this control method is to achieve a constant flow rate of a desired reactant which is introduced into the reactor in a stream in which the concentration of the desired reactant varies, so that the desired total production is achieved.
Similarly, methods for controlling operation of filters, such as that disclosed in U.S. Pat. No. 4,358,827, does not achieve constant efficiency. Rather, the object of such methods is to optimize filtration operation. Even assuming such a method, which is directed to dewatering sludge, were applicable to the phosacid/gypsum separation step, operation in accordance with the method disclosed therein would not result in a constant efficiency operation.

Automatic control system for a chemical process, especially a wet process phosphoric acid plant


A motor vehicle that includes a body having a support structure, a high-voltage battery having a battery housing and at least one battery module arranged in the battery housing. The battery housing is arranged on and attached to the support structure to serve as a main floor panel. A battery cover is detachably arranged on the underside of the battery housing to serve as underride protection and facilitate access to the at least one battery module.

It is known that motor vehicles can utilise a support structure, in particular, comprising longitudinal members and crossmembers, as bodies. The support structure can then, in particular, form a so-called self-supporting body of the vehicle.
Vehicles usually use a floor plate or a floor panel, also known as a main floor, main floor plate, main floor panel, as the bottom delimitation of the vehicle. The main floor panel then usually likewise has a supporting function as a body component of the vehicle. The underside of such a main floor panel can also act as underride protection which protects the vehicle from contamination from underneath the vehicle.
In recent times, high-voltage batteries have been increasingly used as drive batteries for electric and hybrid vehicles. These high-voltage batteries are usually relatively large and must therefore be arranged in a space-saving manner in a vehicle.


The present invention refers to a fibrous product containing cellulosic fibers, which can replace asbestos and comprises in the form of a sheet slightly refined cellulosic fibers in association if the occasion arises, with other fibers, at least one flocculating agent, at least one binder and at least one mineral filler, the said sheet being if the occasion arises, impregnated and smoothed.. The invention likewise refers to the method of preparation of the said fibrous product in accordance with the papermaking techniques.. This fibrous product is useful in the field of covering panels.

The present invention refers as a new industrial product to a fibrous product which contains cellulosic fibres and can replace asbestos. It refers likewise to the method of preparation and the use of the said fibrous product, in particular in the field of covering panels. It is aimed in particular at the obtaining of a support comprising cellulosic fibres associated if the occasion arises, with non-cellulosic fibres, having good dimensional and thermal stability, resistance to water and the humidity in the air and intended in particular to replace asbestos in the production of coverings such as ground coverings or "cushion floor" which are designed starting from an asbestos sole.
It is known that the employment of asbestos implies
(i) recourse to complicated installations bringing about considerable investment and operational expenses, and PA1 (ii) respect for very strict rules of safety and hygiene in order to avoid any risk of absorbtion or inhalation of asbestos fibres and dust. PA1 (a) slightly refined cellulosic fibres having a Schopper-Riegler degree lying between 15 and 35, in association if the occasion arises, with other fibres, PA1 (b) at least one flocculating agent, PA1 (c) at least one binder, and PA1 (d) at least one mineral filler and if the occasion arises, other additives arising in the paper industry, such as retention agents, pH- regulating agents, dry state resistance agents, colorants and antibiotic substances. PA1 (a) slightly refined cellulosic fibres having a Schopper-Riegler degree lying between 15 and 35, in association if the occasion arises, with non-cellulosic fibres, PA1 (b) at least one flocculating agent, PA1 (c) at least one binder, and PA1 (d) at least one mineral filler, in order to obtain the cellulosic product in the form of a sheet; and, if necessary: PA1 (e) at least one sizing agent (in order to reduce the absorbtion of water by the fibres) such, in particular, as the anhydrides of dicarboxylic acids, the dimeric alkylketenes and paraffin emulsions (advantageously 0.1 to 2 parts by weight of at least one sizing agent will be employed per 100 parts by weight of fibres (a)); PA1 (f) at least one retention agent chosen from the group consisting of: PA1 (g) at least one lubrication agent, the preferred lubrication agents from Stage (1) in accordance with the invention being fatty acid derivatives so as to favour anti-adherance of the resulting sheet to the wet presses, the felts and the dryer cylinders; and if the occasion arises, PA1 (h) other additives such, in particular, as one or more agents for resistance to the dry state such as cold-soluble starch, alginates, mannogalactans and galactomannan ethers, and one or more colorants (those suitable, in particular, according to need, are the acid, basic or direct colorants). PA1 (.alpha.) a sizing agent of Points (e) and (f) at the rate of 5 to 10 parts by weight of the said sizing agent per 100 parts by weight of latex (amongst the sizing agents which are suitable here may be mentioned the dimeric alkylketenes and paraffin emulsions); PA1 (.beta.) an anti-foaming agent at the rate of 0.1 to 0.3 part by weight per 100 parts by weight of latex; PA1 (.gamma.) a lubricating agent at the rate of 0.5 to 2 parts by weight of the said agent per 100 parts by weight of latex, the lubricating agent preferred being here ammonium stearate which gives better results than the metallic stearates (Ca and Mg); and PA1 (.delta.) at least one antibiotic substance chosen from the group consisting of the bactericides and the fungicides; advantageously two antibiotics will be employed, one acting mainly as bactericide and the other as fungicide, the preferred proportions of each antibiotic substance being 1500 to 2500 ppm by weight with respect to the weight of the sheet obtained in Stage (1) and, in particular, 1500 to 2500 ppm of bactericide and 1500 to 2500 ppm of fungicide.
It is likewise known that if asbestos supports exhibit good properties of dimensional and thermal stability and inputrescibility they do not possess good mechanical properties because they have poor internal cohesion and poor resistance to traction and to tearing.
It is likewise known that it has been proposed to replace asbestos by a fabric comprising cotton and glass wool fibres. Such a fabric displays the disadvantage of being much too stiff.
In order to solve the technical problem of replacement of asbestos a solution is proposed in accordance with the invention, which is different from that of the prior mixture of cotton and glass wool and which calls upon techniques which are purely those of papermaking. Thus the technical solution in accordance with the invention uses conventional papermaking means of manufacture and coating such as flat or inclined or vertical table machines, size-presses, master scrapers, air blades, trailing blades, or rolled coaters and mechanical means such as refining, pressing, and if the occasion arises, smoothing.

Fibrous product containing cellulosic fibers, its method of preparation and its use, in particular in the field of covering panels, in lieu of asbestos