MXPA00002229A - Fluidic pinch valve system - Google Patents

Abstract

There is provided a fluidic pinch valve system 10 for interrupting the flow of material through a conduit assembly. The fluidic pinch valve system 10 generally includes a substantially rigid valve body 100;an axially extended tube member 200 disposed within the valve body 100;and, an injection mechanism 300 coupled to the valve body 100 for injecting a fluid therein. The valve body 100 includes first and second ends and a wall portion 110 extending therebetween. Within the wall portion 110 is formed a bore extending axially from the first end to the second end. An injection port 140 is formed through the wall portion 110 to be in open communication with the bore. The tube member 200 is disposed within the valve body's bore and is formed having distal first and second sealing portions 120a, 120b and a sidewall portion 210 extending therebetween to define an axial passage. The first and second sealing portions maintain substantially flush engagement, respectively, with the first and second ends of the valve body 100. The sidewall portion 210 includes a flex section that is reversibly collapsible, responsive to a fluidic force imparted thereon, to a pinched configuration in which it is adapted to substantially constrict the axial passage.

Description

FLUID VALVE SYSTEM CONFINED BY STRESS BACKGROUND OF THE INVENTION FIELD OF THE INVENTION The fluid or hydraulic valve system confined by constraint, object of the invention, is generally directed to a system for interrupting the flow of material through a tube assembly. More specifically, the hydraulic valve system confined by tightening is an easily interchangeable system that can be driven by hydraulic pressure to tighten or narrow the flow path of a given material. In the transportation of different materials through pipes, intake and discharge ports, and other pipe assemblies, it is extremely important to enable and disable the material flow in a simple but efficient manner, as necessary. Various types of valve systems are known in addition to valve systems confined by stricture to effect this material flow control. These include the spherical valve, shutter and gate type systems. However, except for applications that exhibit the most benign operating conditions, these types of valve systems are usually of limited utility. For example, where the fluid material contains solid particles, the particles can be deposited between or accumulated on the relatively mobile mechanical components of these valve systems. This could interfere with, or interrupt everything, the operation of the system. Valve-type systems confined by stricture are therefore often preferred in numerous applications. It is considered that valve systems confined by stricture are not immune to significant limiting factors. Valve-confined valve systems generally operate by throttling the flow path of the material to a closure. This requires some degree of flexibility in this segment of pipe assembly being tight. Accordingly, in valve systems confined by stiffening commonly a sleeve member containing rubber material or other elastic material is employed. To meet the requirements of strength, structural integrity and durability in many applications, however, the sleeve member must be reinforced by incorporating fibrous material such as fiberglass, kevlar, carbon and the like into the same material. The too much inelasticity that allows high fibrous materials to serve in their reinforcing function currently remains at odds with the elastic component of the sleeve member, so that repeated throttling, particularly under difficult operating conditions, tends to induce premature failure of the sleeve member. The fibrous material is actually incorporated in many cases in a separate reinforcing layer that progressively separates from the more elastic layer of the sleeve member when repeated strangulation is undergone. The substantial inelasticity of the reinforcing fibrous material gives rise to another limiting factor for valve systems confined by stricture. A sleeve member is only as elastic as its last elastic layer (s). Although it is possible to employ measures such as arranging the fabric of the fibrous reinforcement material to increase the stretchability of any reinforcing layer. This would tend to compromise the reinforcing capacity of the layer. Even with measures taken to increase its stretch capacity, then, the reinforced sleeve member must be of sufficiently greater dimension in the axial length than in the transaxial or diametral width to allow adequate stiffening. The valve systems confined by stiffening incorporate these reinforced sleeve members are, for this reason, much larger in axial length than comparable valve systems of another type. These can not be used to replace existing valve systems of different types without also using extensive modification or adaptation measures. This is especially true since in many applications the dimensions of the valve systems are governed by what length / universal standards. they exclude the high proportions / diameter that necessarily characterize these valve systems confined by stricture. A third limiting factor for these valve systems confined by stricture, acquaintances comes from your requirement to lengthen a reinforced sleeve member. A sufficiently reinforced sleeve member tends to be highly resistant to the stretching necessary for the pinching action. This imposes high requirements with the actuator that is used to drive the ex action. Thus, a mechanical actuator is commonly used to ensure adequate constriction, or constriction, of the path of material flow. The application of mechanical force in a sleeve member presents yet another potentially limiting factor for the systems of. valves confined by known strictures. Moving mechanical parts inherently require the introduction of undue complexity in the resulting valve system, unnecessarily raising the potential for system failures. In spite of carefully implemented preventive measures, in addition, dust or other particles invariably accumulate and settle between the moving parts. Accordingly, there is a need for a modular valve system confined by stricture that is substantially immune to premature failures of its sleeve member that can be confined by stricture. There is a need for this valve system confined by stricture having an axial ratio length to width or length to diameter sufficiently low compared to other types of valve systems. There is another need for a valve system confined by stricture that is easily operated by non-mechanical means.

PREVIOUS TECHNIQUE Valve systems confined by stricture are known in the prior art. The most important prior art known to the applicant includes U.S. Patent Nos. 5,207,409; # 5,036,287; # 4,906,917; # 4,824,072; r # 4,642,833 # 4,372,528 # 4,345,735 4,330,101;; # 4,310,140 # 4,205,697 # 4,191,358 4,191,391; i # 4,108,418 # 4,092,010 # 3,965,925 3,831,085; t # 3,826,461 # 3,775,680 3,640,354; and # 3, 197, 173 However, none of the systems of the prior art incorporate the combination of features now incorporated by the hydraulic valve systems confined by the present invention. For example, U.S. Patent No. 5,207,409 issued to the inventor of the hydraulic valve system confined by the present invention discloses a restrictive, interchangeable confined valve system wherein the tightening action is performed by mechanical means. The system employs a goat foot lever assembly that includes a pair of valve closure members that mechanically clutch and throttle until a flexible sleeve member that otherwise serves as u is closed. s gment of the conduit determined for the flow of material.

COMPENDIUM OF THE INVENTION A primary objective of the present invention is to provide a modular valve system confined by a snap that can be easily operated by the hydraulic force to narrow a flow path of the determined material. Another object of the present invention is to provide a confined valve system by constraint which is' exchangeable in modular form with the valve systems of another type. Another object of the present invention is to provide a valve system confined by stricture where the tightening occurs along a laterally directed contraction seam, responsive to a hydraulic force.

Still another object of the present invention is to provide a valve system confined by high strength, durability and reliability. Yet another object of the present invention is to provide a valve system confined by stricture that is simple in structure and operation. These and other objects are achieved in a hydraulic valve / shaped system confined by stiffening / in accordance with the present invention. The confined valve system, by stricture hereof, generally consists of a substantially rigid valve body; a tube member extending axially, located inside the valve body; and, an injection mechanism also coupled to the valve body for injecting a fluid therein. In the valve body it includes the first and second ends and a wall portion extending between them. Within the wall portion an orifice is formed extending axially from the first end to the second end. An injection opening is formed through the wall portion to be in open communication with the hole. The tube member is located within the orifice of the valve body and is formed by having the first and second obturating, distal portions and a side wall portion extending therebetween to define an axial passage. The first and second sealing portions maintain substantially butt engagement respectively, with the first and second ends of the valve body. The side wall portion includes a flexible section that can be folded in a reversible manner, responsive to a hydraulic force imparted thereto, to a choked configuration in which it is adapted to substantially constrict the axial passage. In one embodiment, the tube member is formed with a flexible section that includes at least one pair of deformable annular ridges and a segment for deformable contraction, located therebetween. The contraction segment is folded in response to the hydraulic force to a linearly extended transverse contour when the flexible section is folded to the choked configuration. The contraction segment is inclined so that this linearly extended transverse contour is oriented in a predetermined transaxial direction.

BRIEF DESCRIPTION OF THE DRAWINGS Figure IA is a schematic diagram of one embodiment of the present invention, including a partially separated, transverse view of a portion thereof prior to hydraulic activation; Figure IB is a schematic diagram of one embodiment of the present invention, including a cross-sectional view, partially separated, of a portion thereof during hydraulic activation; Figure 2 is a perspective view of a portion of the embodiment of the present invention shown in Figure IA; seen in / Figure 3 is a perspective of another portion of the embodiment of the present invention shown in Figure IA; Figure 4A is a cross-sectional view of a portion of the embodiment of the present invention shown in Figure LA; Figure 4B is a sectional view of a portion of the embodiment of the present invention shown in Figure IB; Figure 5 is a cross-sectional, axial, partially cutaway view of a flexible section of the tube member in an alternative embodiment of the present invention; Y Figure 6 is a cross-sectional, transaxial view of a contraction segment of the tube member in the embodiment of the present invention shown in Figure 5.

DETAILED DESCRIPTION OF THE MODALITIES Now with reference to FIGS. 1A-3, a mode of a valve hydraulic system confined by restriction and formed in accordance with the present invention is shown. The valve-confined valve system 10 generally includes a valve body 100 having an orifice extending axially therethrough from one end to the other, an axially extending tube member 200 located within the valve body orifice, and a fluid injector 300 coupled operatively to it. As a modular unit, the valve system confined by restriction 10 is adapted for coupling to or between components 20 (only one shown) of a pipe or other pipe assembly. Once installed in the given tube assembly, the valve system confined by a stop 10 serves as a tube segment when free flow of a working material through the tube assembly will occur. When the free flow is to be interrupted, a suitable fluid is injected into the valve body 100 so that an intermediate portion of the tube member 200 is folded up to sufficiently tighten the flow path of the tube segment otherwise formed therethrough. . The valve body 100 is manufactured as a substantially rigid structure formed of any material known in the art to be suitable for the operating conditions found in the proposed application. In exemplary applications, the valve body 100 is preferably formed of steel or other composition of comparable strength, density and sufficient temperature / durability to withstand the extreme pressure, or repeated contact with potentially abrasive and corrosive materials encountered. during operation. The valve body 100 is formed with the mounting flanges 120a, 120b which facilitate the secure coupling thereof to the component or other parts of the given pipe assembly.

Extending axially between opposite mounting flanges 120a, 120b is a wall portion 100, an upper region? '2"from which a hole 130 is formed. An injection aperture 140 extends through this hole 130 to serve as a guide. for injection into the valve body orifice of a fluid that actuates the constriction One or more regions 114 of the wall portion 110 are bent in a predetermined manner to sufficiently accommodate the contour of the unfolded body of the tube member 200. The member tube 200 is preferably dimensioned and contoured to fit tightly within the orifice of the valve body 100. This can be formed of any material and structural configuration known in the art that makes it suitable for the environmental and operational extremes with which it will find itself in the application proposal, preferablyThis is formed with at least one component that is practically elastic such as rubber or other comparable material and at least one reinforcing component containing fibrous material such as glass fiber, kevlar, carbon fibers and the like. Although not delineated as such in Figures 1A-3, the tubular member 200 may be formed with a multilayer construction wherein at least one substantially elastic layer of a suitably elastic composition is coated with a substantially inelastic reinforcing layer. The reinforcing layer will have a reinforcement fiber woven therein to form a predetermined degree of flexibility in the layer. The tubular member 200 is preferably formed with a sidewall portion 210 terminating axially on the first and second flanged ends 220a, 220b to define an axial passage therethrough. In an intermediate part of the sidewall portion 210. a flexible section is defined which preferably includes a pair of formable annular flanges 214 and a deformable contraction segment: 215 located therebetween. The flexible section is adapted to be reversibly folded in response to the force imparted therein by the fluid injected through the injection opening 140 towards and accumulated within the orifice of the valve body. The force applied to the flexible section by the injected fluid is illustrated by the plurality of directional arrows 40.

The contour and dimensions of the flexible section are such that when a sufficient level of hydraulic force is generated by. accumulation of the fluid injected around it, as indicated in the arrows 40, the contraction segment 215 is completely deviated to substantially throttle the axial passage of the tube member. The flexible section is then in its folded, or strangled configuration. The deflection of the flexible section to its folded configuration is accommodated by the annular flanges 214 which provides sufficient clearance in the material of the side wall of the tube member 200 that the material can simply flex and extend, instead of lengthening. This is important for several reasons. Prevents premature fatigue and material failure that invariably results from forced, repeated stretching of the reinforcement or other component / layer of inelastic material of the sidewall portion of the tube member 210 where the folding of the contraction segment 215 takes place in the absence of flanges annular 214 or other of these provisions. The absence of any need for forced stretching also facilitates the functional demands on the means for actuating the nip, after which less force is required to flex, or extend, the sidewall material as compared to the stretch. Hence, greater durability and efficiency is realized in the valve hydraulic system confined by 10 of this. In addition, much greater radial deviation is allowed for the contraction segment 215 by the arrangement of the annular flanges 214 or the like. Without these, a significantly greater axial extension of the material of the side wall 210 is required to allow the stretched deviation of the contraction segment 215 necessary for full contraction of the axial passage of the tube member. This requires a larger total axial dimension for the regulation of the valve system confined by stricture. In many applications, this would cause the valve system confined by resultant stricture to exceed ASME, DIN or other applicable standards. The potential modular capacity of this valve system confined by stricture would then be totally undetermined, because this could not replace, without extensive adaptation or modification measures, the valve systems that comply with the applicable standards. The arrangements made in accordance with the present invention provide in the valve system confined by 10 herewith the overall dimensions of the valve system completely in accordance with ASME and other widely applicable standards.

When the contraction of the material flow path is effected by a stretching of the material of the side wall of the tube member, in addition, the capacity of the material to withstand the flow pressures of materials carried therein is compromised by the stretching of the material . The full capacity of the tube member 200 to withstand the pressures of the material flow and thus maintain adequate shrinkage is thus conserved in accordance with the present invention. It is important in almost all applications that a valve system is highly sensitive. That is, the valve system must close the determined flow path, then reopen it, immediately when it is activated accordingly. The degree of sensitivity in the reopening of a flow path once closed is a particularly problematic factor in valve systems confined by hydraulic action restriction such as the target system 10, where no affirmative means is present to force open the flow path. In accordance with the present invention, the annular flanges 214 serve to push the flexible section to a non-folded, or open, configuration. This avoids the need for means in addition to the reduction or elimination of the hydraulic force to reopen the axial passage after a period of constriction. The trend of member tube to otherwise remain in the folded or contracted state, is overcome by this push. Jump up ^ The hydraulic activation of the tightening action in the valve system confined by 10 stipulation of the present offers several advantages, not the last of which is the removal of foreign / moving mechanical components. This not only optimizes the overall simplicity of the ^^ system, greatly improves the reliability and durability of the system. With the elimination of components in ^ 10 movement comes the indispensable elimination of potential malfunction or complete failure due to dust or other particles that deposit between or accumulate on them. The removal of the mechanical components that would directly engage portions of the tube member 200 15 also eliminates abrasive contact that would otherwise result from repeated tightening cycles. According to the present invention, the hydraulic action can be effected by injecting a gas or a liquid through the injection opening 140 at a predetermined injection pressure. As it is carried out pneumatically or hydraulically, it is important that the resulting space between the side wall portion 210 of the tube member 200 and the wall portion 110 of the valve body 100 is practically sealed against leakage of the determined fluid. Only then the injected fluid can operate to the injection opening 140. The injector 300 can, if necessary, include its own pump or other hydraulic pressure generating device. A source of pressurized pneumatic or hydraulic fluid in many applications is already provided at the determined site. In any case, the fluid injector 300 includes a filter regulator 310 which receives the pressurized fluid, as indicated by the directional arrow 30, and passes the filtered and regulated fluid stream to a valve mechanism 320 which then selectively directs the current of the fluid to the injection aperture 140, as indicated by the directional arrow 35. The regulating filter 310 may be any suitable device known in the art and available commercially. For example, this can, in pneumatic applications, be the integrated B35 filter / regulator manufactured by (Watts FluidAir, Inc., of Kittery, Maine.) Otherwise, the filter and regulator can be implemented in separate devices such as the F35 filter. and the regulator R35, both also manufactured by Watts FluidAir, Inc. The valve device 320 can be any device known in the art and commercially available that is suitable for proposed application, for example, it can be a valve operated by solenoid, three senses (series 34, series 35, series 100 or series 200) manufactured by MAC Valves of Wixom, Michigan, or other devices as well.In the alternative, the filter-regulator 310 • and the valve device 320 can be manufactured in a single device the pressure controller provide series 5 PPC5A also manufactured by MAC Valves. Returning to Figures 4A-4B, a cross-sectional view of the contraction segment 215 of the tube member 200 is shown in the open (Figure 4A) and closed (Figure 4B) configurations. In many applications, it is highly desirable to strangle shrinkage segment 215 along a laterally directed contraction seam 219. Where particulate residues are carried in the flow of material through the determined pipe assembly, the residue invariably it deposits and deposits in the bend formed at the lower end of the contraction seam 219, where this seam contracted 219 is vertically directed (or inclined). Even if insignificant amounts of residue are thus deposited in any open-nonspecific cycle, a progressive accumulation of this accumulative residue invariably results in operation for a prolonged period, progressively compromising the ability of the tube member to completely throttle the axial passage. To ensure that the contraction segment 215 25 is folded along the laterally extended contraction seam 219, ie, to a linearly extended transverse contour oriented in a lateral direction; the contraction segment 215 is pushed with consequence. It is possible to employ any of the numerous pushing means. For example, a repeated series of conditioning premanipulations can be performed to effectively contract the contraction segment 215, so that it can be folded and bent into regions 217a, 217b. Also, the thickness of the side wall portion 210 can be minimized in those diametrically opposed side regions 217a, 217b of the contraction segment 215. For example, at least one pair of these opposite side regions 217a, 217b can each be formed with a dimension of thickness less than the average thickness dimension, of the total contraction segment 215. The choice of the actual medium by which the contraction segment 215 is urged to fold along the laterally extended contraction seam 219 is not important for the present invention, as long as it does not detrimentally affect other aspects of a system 10 formed in accordance with the present invention. Now with reference to Figures 5-6, a tube 400 formed according to another embodiment of the present invention is shown. The tube member 400 includes a sidewall portion 410 formed with a multilayer construction including a reinforcing layer 402, an elastic primary layer 404, and axially extending through the flexible section at least a secondary elastic layer serving primarily as an internal coating. As in the above embodiment, the flexible section of the sidewall portion 410 includes a pair of annular flanges 414 between which a shrink segment 415 is located. The additional elastic layer 406 prevents any turbulent disturbance that may result when the material that flows through the axial passage of the tube member 400 into the annular space immediately below each annular rim 414. Where the operating conditions are such that the probability of a detrimental effect is significant, the coating layer 406 covers the annular spaces below the edges of the annular spaces. rims 414 to maintain the flow of currentilinear material. With the fold of the shrink segment 415, 406./ is caused to stretch the coating layer / The coating layer 406 is preferably formed of an elastic rubber composition or the like, however, well adapted for stretching that the risk of fatigue and premature failure of the material does not represent a significant consideration. As shown in Figure 6, the thrust of the contraction segment 415 in this embodiment is effected by the suitable arrangement of the cumulative thickness of the wall in different regions thereof. The cumulative dimension of the thickness a for the diametrically opposite side regions of the contraction segment 415 becomes sufficiently smaller than the thickness dimension d in the other regions. Accordingly, the contraction segment 415 tends to bend and fold in its laterally opposite regions (having the thickness dimension a and smaller) to collapse to a transverse contour facing the sides. Although this invention has been described in connection with the specific forms and modalities thereof, it will be appreciated that different modifications in addition to those described above may be interposed without departing from the spirit or scope of the invention. For example, equivalent elements can be substituted for those specifically shown and described; certain characteristics can be used independently of other characteristics; and, although circular transverse contours are shown for the valve body, the tube member and the components of the determined tube assembly, it is possible to employ other transverse, noncircular contours; all without departing from the spirit or scope of the invention as defined in the attached clauses.

WHAT IS CLAIMED IS-: 1. A hydraulic valve system confined by restriction comprising: .__ (a) a substantially rigid valve body having the first and second distal ends and a wall portion extending therebetween, the valve body having an orifice extending axially from the first end to the second end, the valve body having an injection opening formed through the wall portion, the injection opening being in open communication with the hole; (b) an axially extended tube member located within the orifice, the tube member having a first and second distal sealing portions and a side wall portion extending therebetween to define an axial passage, the first and second sealing portions being in substantially butted engagement respectively with the first and second ends of the valve body, the side wall portion including a flexible section that can be reversibly folded to a throttled configuration in response to a hydraulic force, and the flexible section being adapted to substantially throttle the axial passage when it is in the strangled configuration; and (c) the injection means coupled to the injection opening of the valve body for injecting a fluid through it and thereby generating a hydraulic force. 2. The valve-confined hydraulic system as defined in claim 1, wherein the flexible section of the tube member includes at least one pair of deformable annular flanges and a deformable contraction segment located therebetween. 3. The valve-confined hydraulic system according to claim 2, wherein the annular flanges extend without substantial stretching thereof when the flexible section is folded to the choked configuration. 4. The valve-confined hydraulic valve system as recited in claim 3, wherein the contraction segment collapses to a linearly extended sectional contour when the flexible section is folded to the strangled configuration. 5. The hydraulic valve system constrained by stiffening as recited in claim 4, wherein the contraction segment is urged to fold substantially along a contraction seam oriented in a predetermined transaxial direction. 6. The hydraulic valve system confined by stricture as mentioned in claim 5, wherein ^ The contraction seam is directed laterally. 7. The valve-confined hydraulic system according to claim 2, wherein the first and second sealing portions of the tube member each include a flanged, resilient end. ^^ extending axially beyond the valve body, each flanged end having a flange formed therein. ^ 10 annular directed radially outwards. 8. The hydraulic valve system confined by stricture as recited in claim 7, wherein the injection means injects a pneumatic fluid. 9. A valve module confined by hydraulic action, comprises: (a) a substantially rigid valve body having the first and second distal ends and a wall portion extending therebetween, the valve body having an orifice extending axially from the valve body. first end to the second end, the valve body having an injection opening formed through the wall portion, for injection of a fluid therethrough, the injection opening being in open communication with the orifice; (b) a tube member located coaxially within the hole, the tube member having a side wall portion defining an axial passage therethrough, the side wall portion axially terminated in the first and 5 second resilient ends with flange, the first and second tab ends extending axially beyond and respectively engaging substantially abutting the first and second ends of the valve body, the side wall portion including a flexible section, the flexible section being reversibly deformable to a strangulated configuration in response to fluid injection, the flexible section being adapted to substantially throttle the axial passage when in the choked configuration. 10. The valve module confined by hydraulic action, as mentioned in claim 9, wherein the first and second flanged ends have formed therein an annular flange directed radially outwardly. 11. The valve module constrained by hydraulic action, as mentioned in claim 10, wherein the flexible section of the tube member includes at least one pair of deformable annular flanges and a deformable contraction segment located therebetween. . 12. The valve module constrained by hydraulic action, as mentioned in claim 11, wherein the annular flanges are extended without substantial stretching thereof when the flexible section is deformed to the choked configuration. 13. The hydraulically constrained confined valve module, as recited in claim 12, wherein the contraction segment is folded to a linearly extended sectional contour, when the flexible section is deformed to the choked configuration. 14. The valve module constrained by hydraulic action, as mentioned in claim 13, wherein the contraction segment is urged to fold into a linearly extended sectional contour oriented in a lateral direction. 15. A valve-confined hydraulic valve system consists of: (a) a substantially rigid valve body having the first and second distal ends and a wall portion extending therebetween, the valve body having a hole extending axially from the first end to the second end, the valve body having an injection opening formed through the wall portion, the injection opening being in open communication with the orifice; (b) an axially extending tube member located within the bore, the tube member having a multi-layered sidewall portion defining an axial passage therethrough, the sidewall portion terminating axially in the first and second-- i-ends resilient, with tabs, the first and second ends with > _ flanges extending beyond and respectively engaging in substantially abutting manner with the first and second ends of the valve body, the side wall portion including a flexible section having at least one pair of axially located annular r-edges and a shrink segment. located therebetween, the flexible section being reversibly deformable to a throttled configuration in response to a hydraulic force, and the flexible section being adapted to substantially contract the axial passage when in the throttled configuration; and (c) the injection means coupled to the injection opening / of the valve body for injecting therewith a fluid to thereby produce a hydraulic force. 16. The valve system confined by stiffening, as recited in claim 15, wherein the multilayer sidewall portion further includes a substantially cylindrical sheath layer extending coaxially through the flexible section. P 17. The valve system confined by stricture, as mentioned in claim 16, wherein the first and second flanged ends of the tube member have formed therein an annular flange directed radially outwardly. 18. The valve system confined by stricture, as recited in claim 17, wherein the annular flanges are extended without substantial stretching thereof when the flexible section is deformed to the choked configuration. .19. The valve system confined by stricture, as mentioned in claim 18, wherein the contraction segment is pushed to fold to a laterally extended sectional contour when the section • Flexible is deformed to the strangulated configuration. 20. The valve system confined by stricture, > as mentioned in claim 19, wherein the contraction segment has formed therein at least one pair of folded, transaxially opposed regions. 21. The valve system confined by stricture, as mentioned in claim 19, wherein the contraction segment includes at least one pair of thrust regions, transaxially opposite, each Axis pushing the region having a thickness dimension less than an average thickness dimension of the contraction segment. collapses from xr? anc_ ?. reversible in response to a fluidic force imparted therein, to a tight configuration in which the axial passage is adapted to the axial passage. .ti £ z ^^^

Claims (3)

1. FIG.
2. 2 FIG.
3. 3 FIG.4A FIG.4B FIG. 5 FIG.6