Abstract:
A pinch valve for controlling fluid flow through flexible tubing is disclosed. The valve has a frame for accommodating flexible tubing and a tube-constricting arrangement, which arrangement includes a pair of arc sections on one side of the frame forming a throat or crimping channel transverse to the tube axis and a blade member extending correspondingly and transversely on the other side. An actuator reciprocally positions the blade member between an open and closed position. When the blade member is in the closed position, flexible tubing is crimped within the throat, preventing fluid flow therethrough. When the blade member is moved away from the tubing in an open position, the flexible tubing reverts to a relaxed condition and allows fluid flow therethrough. The pinch valve is utilizable with a bladder that provides a closed system and assists in throttling the flow of the fluid.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This is a Continuation-in-Part of an application entitled PINCH VALVE filed Jan. 11, 2007, now abandoned Ser. No. 11/652,976, which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a manually-operated pinch or crimp valve for regulating the flow of a fluid through flexible tubing. More particularly, the valve operator is a two-position device that requires low actuator pressure for stopping or initiating fluid flow, which characteristic is especially useful for handling fluids stored under high pressure. 
     2. Description of Prior Art 
     Pinch valves are generally provided to a continuous duct, tube, or other flexible conduit or line to control the flow of fluid through that line. Such valves control or terminate fluid flow by constricting or pinching the line, thus maintaining fluid under pressure within the line and upstream of the valve. While a number of different types of pinch valve designs are known, many of the existing pinch valves in use are either complicated in design and construction with too many component parts or are inefficient in actually maintaining a closed condition. Frequently, prior art pinch valves, when closed, allow leakage past the valve. 
     Pinch valves have many applications in industry, and a wide variety of valves have been developed to serve different industrial requirements. For some demanding applications requiring high flow rates, high pressures, high temperatures, no contamination, corrosive materials handling or precision metering, such as semiconductor processing, precision instruments, medical, pharmaceuticals, chemical, food processing or the like, existing pinch valve designs are not fully satisfactory. 
     The limitations of existing pinch valve designs include factors such as: construction materials such as plastics, elastomers, and metals; sliding surfaces which lead to wear, cleaning and sanitation difficulties; and, complex geometry also having accompanying cleaning and sterilization difficulties. Size, and cost limitations are other complicating factors in pinch valve design. 
     In the past, numerous pinch valve designs have been suggested and such designs have been generically categorized by the nature of the tube compression encountered—whether by roller tube or by perpendicularly reciprocated tube contacting element (a blade) and also by how the blade is operated. Operating schemes have included springs, levers, and screw actuators. 
     The inventor hereof is also the inventor of U.S. Pat. No. 6,883,773 issued Apr. 26, 2005, which patent describes a pinch valve controlling fluid through flexible tubing. In this valve, an actuator, upon the application of pressure, overcomes the spring bias causing the pinch element to move away from the collapsed flexible tubing and initiate fluid flow therethrough. While this valve was adequate at low fluid pressure, at higher fluid pressures, it was ascertained that the manual pressure at the actuator was unacceptable. 
     Through the prior patent the inventor hereof became familiar with the following patents, all of which are original classification 251/7 or cross-referenced thereinto: 
     
       
         
               
               
               
             
               
               
               
             
           
               
                   
               
               
                 patent 
                 Inventor 
                 Issue Date 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 48,421 
                 Matthews, Jr. 
                 June 1865 
               
               
                 307,871 
                 Richtmann 
                 November 1884 
               
               
                 2,471,623 
                 Hubbell 
                 May 1949 
               
               
                 3,262,670 
                 Russell 
                 July 1966 
               
               
                 4,634,092 
                 Daniell et al. 
                 January 1987 
               
               
                 6,536,738 
                 Inoue et al. 
                 March 2003 
               
               
                   
               
             
          
         
       
     
     In the course of preparation, for the within disclosure several patents and published applications became known to the inventor hereof. The following patents are believed to be relevant and are discussed further as to the significance thereof: 
     
       
         
               
             
               
               
               
             
           
               
                   
               
               
                 U.S. patents 
               
             
          
           
               
                 patent 
                 Inventor 
                 Issue Date 
               
               
                   
               
               
                 4,029,441 
                 Fischer, L. 
                 Jun. 14, 1977 
               
               
                 4,071,039 
                 Goof, S. K. L. 
                 Jan. 31, 1978 
               
               
                 4,688,753 
                 Tseng, et al. 
                 Aug. 25, 1987 
               
               
                 4,895,341 
                 Brown et al. 
                 Jan. 23, 1990 
               
               
                 4,960,259 
                 Sunnanväder et al. 
                 Oct. 2, 1990 
               
               
                 5,088,522 
                 Rath et al. 
                 Feb. 18, 1992 
               
               
                 6,036,166 
                 Olson, D.L. 
                 Mar. 14, 2000 
               
               
                 6,536,738 
                 Inoue et al. 
                 Mar. 25, 2003 
               
               
                 6,554,589 
                 Grapes 
                 Apr. 29, 2003 
               
               
                 6,840,492 
                 Boyne-Aitken 
                 Jan. 11, 2005 
               
               
                 6,883,773 
                 Mattheis 
                 Apr. 26, 2005 
               
               
                 6,948,696 
                 Aanonsen et al. 
                 Sep. 27, 2005 
               
               
                   
               
             
          
         
       
     
     
       
         
               
             
               
               
               
             
           
               
                   
               
               
                 U.S. PATENT APPLICATION PUBLICATIONS 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 2005/0258382 
                 Yang 
                 Nov. 24, 2005 
               
               
                 2006/0049371 
                 Ohnishi 
                 Mar. 9, 2006 
               
               
                 2006/0138369 
                 Tomioka et al. 
                 Jun. 29, 2006 
               
               
                   
               
             
          
         
       
     
     Several of the above patents have plungers acting upon flexible tubing in various configurations. Goof &#39;039 uses fluid pressure within a control assembly to regulate plunger position and fluid flow. Tseng et al. &#39;753 drives a wedge-shaped tongue member to force the tubing onto a tubing occluding surface, which surface conforms the original bottom half of the tubing. Grapes &#39;589 has a tube tunnel in which to dispose the flexible tubing and lowers a plunger thereagainst. The plunger has a spherical tube contacting end dimensioned to fit the exterior of the tube. None of these operate into a throat of diminishing size. In systems operating under high pressure, such arrangements are not suitable for manual actuation. 
     In addition to plungers, various means for protecting the flexible tubing that is pinched to cut off fluid flow. Rath et al. &#39;522 teaches a pump hose with arcuate portions to minimize stress at the hose joints. Brown et al. &#39;341, Sunnanväder et al. &#39;259, and Inoue et al. &#39;738 show sleeve-like casings surrounding the flexible tubing for purposes of avoiding injurious activities in operation. 
     The published patent application to Yang shows a suction hose stop valve having a holder through a central passageway and a swivel cap. Here, when the hose is in the open condition, closure is accomplished by swivelling the cap to fold the hose upon itself. Thereafter the swivel cap is latched to maintain the closed position. 
     Boyne-Aitken &#39;292 patent is representative of a wide variety of tube clamps and clips typically used for intravenous drips or similar fluid delivery. This patent describes two flexible curved beams forming a threshold to the pinch zone of the clamp. These beams act as a stop or retainer preventing free movement between the open segment and the closed segment of the tube clamp and do not have any pinching function once the clamp is open or closed. 
     Prior art pinch valves also teach the use of flexible tubing inserts. The pinch valve of Aanonsen et al. &#39;696 has a resiliently flexible valve member which is folded upon itself. A valve operator selectively exerts a lateral force upon the valve member to unfold the insert and operate the valve. 
     The Ohnishi published patent application utilizes various projections on the inner wall of the flexible tubing to ensure complete closure when pressure is applied to the outside of the tubing. The patterned projections also enable control of microflow through the system. 
     The present invention provides a novel pinch valve for use with liquids under high pressure. The use of the blade member to force tubing between arc or arc-like segments provides a mechanical advantage over the prior art pinch valves. The use of the arc or arc-like segments, along with its corresponding flexible movement, to open or close the pinch valve and to allow for the flow of the liquids, requires lower hand pressure and less spring action. The arc or arc-like segments overcome the high friction that results from bending the flexible tubing. Such novel design allows for the containment of high pressure liquids when in a closed position, with the ability to open the pinch valve by solely using hand pressure. 
     While it is difficult to provide a pinch valve design that satisfies all the requirements of industry, there is a need for a normally closed valve or a normally open valve with improved features for demanding applications. For example, it is desirable for such a valve to provide complete shutoff at high pressures and require drgonomically suitable manual operating characteristics. 
     SUMMARY OF THE INVENTION 
     The present invention describes a pinch valve for the purpose of constricting and releasing the flow of fluid through flexible tubing. The pinch valve is composed of a frame adapted to surround the flexible tubing, a pair of tube-constricting members or arc segments on one side of the interior of the frame, a blade member extending transversely on the other side of the interior of the frame, and an actuator for manually activating the pinch valve. The flexible tubing is threaded between the tube-constricting members and the blade member. 
     The pair of tube-constricting members is operable between a relaxed condition and a flexed condition. When it is in the flexed condition, a channel is formed that is transverse to the longitudinal axis of the flexible tubing. 
     The blade member is reciprocally positionable between an open position and a closed position. When the blade member is in the closed position, the tube-constricting members are in a flexed position, and the flexible tubing is crimped within the transverse channel, thereby preventing fluid flow therethrough. With the actuator depressed and the blade member in the open position, the tube-constricting members revert to a relaxed condition, allowing fluid flow through the flexible tubing. The pinch valve is constructed so that the manual force required for operation of the actuator is, even at high flow pressures, within the ergonomic range. 
     An alternative embodiment of the pinch valve is composed of a base, an open framework arising from the base having a front, a back, a right- and a left side adapted for threading the flexible tubing through the medial portion of the framework, a blade member disposed between the base and the flexible tubing, a manual actuator, and a restrictive channel having a wide mouth and a narrow throat disposed in the open framework on the actuator side of the flexible tubing. 
     As in the first embodiment, the blade member is reciprocally positionable between an open position and a closed position. When the blade member is in the closed position, it crimps the flexible tubing into a narrowed throat or restrictive channel, thereby preventing fluid flow through the tubing. When the actuator is depressed, the blade member assumes an open position, the restrictive channel releases the flexible tubing to an uncrimped position, and fluid flow is permitted through the flexible tubing. 
     A third embodiment includes the flexible tubing as part of the pinch valve. It also includes a valve body with an opening for the insertion of the flexible tubing, a pinch arm attached to the body and engageable to one side of the flexible tubing passing through the opening, an actuator and a restrictive throat on the valve body on the actuator side of the flexible tubing. A fourth embodiment includes the flexible tubing and a bladder as part of the pinch valve. The bladder is configured to store fluid when the pinch arm is in the closed position. 
     The pinch arm is movable between an open position at which the flexible tubing is not compressed, and a closed position at which the flexible tubing is collapsed due to compression by the pinch arm. The restrictive throat is oriented to accommodate, when the pinch arm is in a closed position, the pinch arm and the flexible tubing in a collapsed condition. 
     OBJECTS AND FEATURES OF THE INVENTION 
     It is thus an object of the present invention to provide an easy to control pinch valve serving a high-pressure fluid source requiring minimal manual pressure to operate. 
     It is another object of the present invention to provide a normally closed valve which is simple in construction and readily assembled. 
     It is a further object of the present invention to provide a pinch valve permitting fluid flow therethrough only when the actuator is depressed. 
     It is yet a further object of the present invention to provide a pinch valve which is easy to install and to incorporate into a flow control system. 
     It is another object of the present invention to provide a pinch valve which is simultaneously operable with multiple tubes. 
     It is a feature of the present invention to utilize, in a hybrid construction, arc segments and a transverse blade as constricting elements for mechanically efficient valve operation. 
     It is a further feature of the present invention that the system operates as a closed system ensuring an anti-contamination environment. 
     It is another feature of the present invention to have the spring biasing means perform dual functions of urging a blade contacting element into the flexible tubing and forming arcuate contacting elements for cooperative functioning therewith. 
     It is yet a further feature of the present invention to maintain the manual pressure required for operation in a normal ergonomic range. 
     Novel features which are considered as characteristic of the invention are set forth in particular in the attendant claims. The invention, itself, however both as to its design, construction and use, together with the additional features and advantages thereof, are best understood upon review of the following detailed description with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The drawing shows the pinch valve of this disclosure in which similar parts in the various views have the same reference designators. 
         FIG. 1  is a perspective view of the pinch valve of this invention; 
         FIG. 2  is a schematic view of the pinch valve of  FIG. 1  showing the arc segments and the relation thereof to the crimped flexible tubing; 
         FIG. 3  is a schematic view of the pinch valve of  FIG. 1  showing the force vectors acting on the flexible tubing; 
         FIG. 4  is a front view of the transverse pinch member of the pinch valve of this invention; 
         FIG. 5  is a side elevational view of the transverse pinch member shown in  FIG. 4  with the side wall thereof partially broken away to show the transverse blade; 
         FIG. 6  is a front view of the outer housing of the pinch valve of this invention; 
         FIG. 7  is a side elevational view of the outer housing shown in  FIG. 6 ; 
         FIG. 8  is a perspective view of the crimp member of the pinch valve of this invention shown prior to assembly thereof; 
         FIG. 9  is a perspective view of the crimp member of  FIG. 8 , but shown in an as assembled configuration; 
         FIG. 10  is a perspective view of a first alternate crimp member for a second embodiment of the pinch valve of this invention showing the bladder adjacent to the flexible tubing set within the transverse channel in a closed position; 
         FIG. 11  is a perspective view of a second alternate crimp member for a third embodiment of the pinch valve of this invention with multiple flexible tubings set within the pinch valve; 
         FIG. 12  is a cutaway perspective view showing the pinch valve of this invention in the normally closed condition; 
         FIG. 13  is a cutaway perspective view showing the pinch valve of this invention operated to the open condition; 
         FIG. 14  is a cutaway perspective view of a fourth embodiment of the pinch valve of this invention in the normally open position; and 
         FIG. 15  is a perspective view showing the pinch valve of  FIG. 14  operated to the closed condition. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to  FIG. 1 , a pinch valve of the present invention is shown and is referred to generally by the reference designator  20 . The pinch valve  20  is constructed with an outer housing  22  with side walls  24  and  26  and a base  28 . The side walls  24  and  26  each have mounting and locking tabs  30  and  32  which are used to secure the pinch valve  20  into a panel (not shown). The outer housing or valve body  22  of pinch valve  20  is further constructed with an aperture or opening  34  therethrough, which aperture  34  is provided to accommodate one or more flexible tubings for the conduct of fluid flow. The pinch valve  20  of this invention is a normally closed valve and is maintained in such condition by the spring or biasing means  36 . The force of the biasing means  36  is overcome by the manual operation of the actuator or pushbutton  38 . 
     The pinch valve  20  of this invention is a hybrid design in that it employs arc or arc-like segments and biasing transverse blade pinch elements in combination with each other. A schematic representation of this effect is shown in  FIGS. 2 and 3 . During the normally closed portion of the operating cycle, a pair of flexible, arc segments  40  and  42 , described in detail hereinbelow, are forced into a flexed condition. In this condition, arc segments  40  and  42  exert tube-constricting forces  44  and  46 . These forces combine with the biasing means or spring  36  which drives the transverse blade or pinch member  48  into the flexible tubing or conduit  50  thereby crimping the tubing  50  in the throat  52  formed by the flexed segments  40  and  42 . The biasing force  54  urges the flexible tubing  50  and the pinch member  48  into the throat  52 , which action also flexes segments  40  and  42 . The use of flexible arc segments  40  and  42 , adds mechanical advantage to the pinch vale and thereby minimizes the force required to bend the tubing  50  concomitantly therewith the construct reduces the surface friction of the tubing  50  against the arc segments  40  and  42 . As shown in  FIG. 11 , the pinch valve  20  is designed to house either a single flexible tubing  50  or multiple flexible tubings  50 . When multiple flexible tubings  50  are harnessed together, the size of the pinch member  48  and throat  52  correspond to the width of the combined flexible tubings  50  when collapsed to flat and, if any, harness separators (not shown). 
     The present invention is designed to work alone or in concert with a self-contained fluid source. One application is in connection with a reservoir such as a bladder. The self-contained fluid source or bladder (as shown in  FIG. 10  as  251 ) is formed by filling the tubing  50 , with fluid while the pinch valve  20  is in the closed position. The flexible tubing is expanded to form a bladder  251 . Alternatively, a separate bladder constructed of a material of sufficient integrity to withstand pressures of up to approximately 40 psi is connected and secured to the tubing  50  providing an air and fluid tight seal. The bladder  251  acts as a storage reservoir and provides control over the pressure of the fluid that is released into the tubing  50  and through the pinch valve  20 . The present pinch valve  20  with the manual actuator  38  operates under pressures as high as approximately 40 psi with appropriate tubing. 
     When the bladder  251  is a separate construct from the tubing, it is filled either prior to connection to the tubing  50  or contains a separate valve or access area for connection to the fluid source (not shown). When the bladder  251  is formed through the expansion of the tubing  50 , the tubing end (not shown) set opposite the pinch valve  20  is connected to a fluid source (not shown) and expanded, while the pinch valve  20  is set in the closed position, by the force of the entering fluid. In general, liquids such as water from a public source are delivered at a rate of 90 psi. Through the use of the tubing  50  as a bladder  251 , the bladder  251  controls the fluid rate of delivery, lowering the rate of delivery to approximately 40 psi, a rate in which the pinch valve  20  is operable through the use of only manual force. 
     The bladder  251  and tubing  50  act as a throttle enabling the use of manual force to control the fluid flow entering the system at rates up to approximately 40 psi. The bladder (shown in  FIG. 10  as  251 ) absorbs the differential between the source of the fluid and the pinch valve  20 . The self-contained nature of the present invention has many industrial uses including, but not limited to, hospital, assisted care facilities, laboratory, or other industries where the delivery of contaminate-free fluids is required. 
     Referring now to  FIGS. 4 through 7  the outer housing  22 , the transverse pinch member  48 , and spring  36  are further described. The transverse pinch member  48 , the side view of which is shown in  FIG. 5  and the front view is shown in  FIG. 4 , is positioned, when assembled, within outer housing  22  and is mounted therein for reciprocal movement between an open position permitting fluid flow through flexible tubing  50  and a close position preventing fluid flow. 
     As shown in this preferred embodiment, the transverse pinch member  48  is constructed as a cage or an open box-like frame with no top or bottom, but with four side walls  56 ,  58 ,  60 , and  62 . An opening  64  extends through pinch member  48  and is adapted to receive flexible tubing  50  therethrough. On the interior of the box-like structure and medial side wall  62 , a blade member  66  spans between side walls  56  and  58 . The side elevation thereof is seen in  FIG. 5  wherein side wall  56  is broken away. The blade member  66  has a central plane substantially normal to the longitudinal axis of the flexible tubing  50  (when the valve is in the open position). Disposed on the exterior of wall  62  is a spring-retaining fitting  68  for spring  36 . Disposed on the exterior of wall  60  is an actuator-receiving stem  70  for actuator  38 . 
     The outer housing  22 ,  FIGS. 6 and 7 , is constructed similar to transverse pinch member  48  in that the housing  22  is also an open box-like frame with no top or bottom, but with four side walls  72 ,  74 ,  76  and  78 . An opening  80  extends through housing  22  and is adapted to receive therewithin the transverse pinch member. The outer housing  22  is dimensioned so that when the transverse pinch member is assembled therein side walls  56  and  58  slidingly engage walls  72  and  74  and openings  64  and  80  align with one another enabling the tubing to pass therethrough and facilitating the reciprocal movement of the pinch member  48 . Disposed on the interior of wall  78  is a spring-retaining fitting  82  for spring  36 . 
     Coil spring  36  is disposed in pinch valve  20  between the spring-retaining fitting  68  of pinch member  48  on the exterior of wall  62  and the spring-retaining fitting  82  of outer housing  22  on the interior of wall  78 . The spring strength is selected for the specific application. The specification thereof turns on the fluid pressure anticipated and the actuator pressure desired for initiating fluid flow. The actuator pressure needs to be ergonomically suited to the marketplace for the product. 
     All of the above-described details occur on one side of the flexible tubing  50  which for descriptive purposes is considered the spring side. On the other side—considered the actuator side, a tube-constricting structure  84 , which includes flexible segments  40  and  42 , is disposed. The construction of a restrictive channel or throat into which the blade member pushes the flexible tubing is the subject of design variations forming the basis for the various configurations expressed herein as separate embodiments. The best mode practice shown in the first embodiment has hinged segments which, when flexed, form the receiving throat. Other embodiments show a static, but resilient throat, and yet another, an inflexible (rigid) throat that collapses when the valve is open. 
     Referring now to  FIGS. 1 ,  8  and  9 , the tube-constricting structure or crimp member  84  is shown in further detail. The crimp member  84  is formed from an elongated rectangular body  86  that is insertable into the housing  22  through opening  80 . At both ends of body  86 , the crimp member  84  has perfect hinges  88  and  90 , enabling end portions  92  and  94  to rest against the exterior of outer housing  22  from the opening  80  to side wall  76 . Intermediate end portions  92  and  94  are flexible segments  40  and  42  hingedly attached to rectangular body  86  and in the relaxed, unflexed condition depending from body  86  in a direction opposite end portions  92  and  94 . 
     Upon completion of assembly, the pinch valve  20  is normally closed and does not permit fluid flow through flexible tubing  50 . In this condition, flexible tubing  50  has blade member  66  urged thereagainst and, in turn, flexes segments  40  and  42  forming a throat  52  therebetween. 
     Referring now to  FIG. 10  a perspective view of an alternate tube-constricting member  184  for a second embodiment is shown. Here the transverse channel or receiving throat  152  is a static, inflexible shell  140  and  142  that is resiliently mounted. Upon applying pressure to pinch member  148  (noting that the balance of the components for the second embodiment are the same as the first), the flexible tubing  150  is crimped within the preshaped throat. When the pushbutton is actuated the flexible tubing is released from the transverse channel  152  and fluid flow is initiated. 
     Referring now to  FIG. 11  a perspective view of an alternate tube-constricting member  284  for a third embodiment is shown. Here the transverse channel or receiving throat  252  formed by hinged, inflexible arcuate members  240  and  242  that is preloaded to the valve open position. Upon applying pressure to the pinch member  248  (here again, the balance of the components for the third embodiment are the same as the first), the flexible tubing  250  (shown with multiple flexible tubings) crimped within the throat formed by the hinged arcuate members and the pinch valve crimps the tubing. When the pushbutton is actuated, the flexible tubing  50  is urged from the throat  252  by the hinge preload and the overcoming of the spring bias. To be sufficiently restrictive the throat  252  is dimensioned to be less than the width of the blade  248  plus four times tubing wall thickness. 
       FIGS. 12 and 13  show the operative positions of the pinch valve of the first embodiment of this invention. Here  FIG. 12  shows the pinch valve  20  in the normally closed condition and  FIG. 13  shows the pinch valve operated to the open condition. In the normally closed condition spring  36  is extended urging transverse pinch member  48  to crimp the flexible tubing  50  and urge the tubing into the throat  52 . In doing so, the tubing  50  flexes segments  40  and  42  causing the arc segments to press against tubing  50 . In this condition the pushbutton  38  is fully extended. The use of flexible arc segments  40  and  42 , minimizes the force required to bend the tubing  50  by reducing the surface friction of the tubing  50  against the arc segments  40  and  42 . 
     In moving the pinch valve  20  to the open condition, pushbutton  38  is fully depressed. With light manual pressure (9 to 15 lbs) the cage-like structure of the pinch member  48  slides within the housing  22  toward the spring end thereof. As spring  36  compresses, arcuate segments  40  and  42  return to a relaxed condition as best seen in  FIG. 9 . As the segments  40  and  42  relax, the flexible tubing  50  is released and is gently pushed from throat  52 . The flexible tubing  50  becomes and open conduit and fluid flow is initiated. Fluid flow continues so long as the pushbutton remains depressed. 
     Referring now to  FIGS. 14 and 15 , a cutaway perspective view of an alternate pinch valve  320  for a fourth embodiment is shown. Here the pinch valve  320  is constructed with an outer housing  322  with side walls  324  and  326  and a base  328 . The side walls  324  and  326  each have mounting and locking tabs (not shown) which are used to secure the pinch valve  320  into a panel (not shown). The outer housing or valve body  322  of pinch valve  320  is further constructed with an aperture or opening  334  therethrough, which aperture  334  is provided to accommodate one or more flexible tubings for the conduct of fluid flow. A spring housing  333  is affixed to the pinch valve  320  to support the spring  336 . The pinch valve  320  of this invention is a normally open valve and is maintained in such condition by the spring or biasing means  336 . To close the pinch valve  320 , the force of the biasing means  336  is overcome by the manual operation of the actuator or pushbutton  338  which is affixed to the spring  336 . Once the valve  320  is closed, the actuator  338  is held in place to maintain closure. 
     The pinch valve  320  of this invention is a hybrid design in that it employs arc or arc-like segments and biasing transverse blade pinch elements in combination with each other. A schematic representation of this effect is shown in  FIGS. 14 and 15 . During the normally open portion of the operating cycle, a pair of flexible, arc segments  340  and  342 , described in detail hereinbelow, are set in a relaxed position. When the pinch valve  320  is pushed into the closed position, the arc segments  340  and  342  are forced into a flexed condition. In this condition, arc segments  340  and  342  exert tube-constricting forces. These forces combine with the biasing means or spring  336  which drives the transverse blade or pinch member  366  into the flexible tubing or conduit  350  thereby crimping the tubing  350  in the throat  352  formed by the flexed arc segments  340  and  342 . The biasing force urges the flexible tubing  350  and the pinch member  366  into the throat  352 , which action also flexes arc segments  340  and  342 . The use of flexible arc segments  340  and  342 , minimizes the force required to bend the tubing  350  by reducing the surface friction of the tubing  350  against the arc segments  340  and  342 . As shown in  FIG. 11 , the pinch valve  320  is designed to house either a single flexible tubing  350  or multiple flexible tubings  350  (as shown in  FIG. 11 ). In order to house multiple flexible tubings  350 , the size of the pinch member  366  and throat  352  correspond to the width of the combined flexible tubings  350 . 
     The present invention is designed to work alone or in concert with a self-contained fluid source. The self-contained fluid source or bladder (as shown in  FIG. 10  as  251 ) is formed by filling the tubing  350 , with fluid while the pinch valve  320  is in the closed position. The flexible tubing is expanded to form a bladder  251 . Alternatively, a separate bladder constructed of a material of sufficient integrity to withstand pressures of up to approximately 40 psi (not shown) is connected and secured to the tubing  350  providing an air and fluid tight seal. The bladder  251  acts as a storage reservoir and provides control over the pressure of the fluid that is released into the tubing  350  and through the pinch valve  320 . The present pinch valve  320  with the manual actuator  338  operates under pressures as high as approximately 40 psi. 
     When the bladder  251  is a separate construct from the tubing it is filled either prior to connection to the tubing  350  or contains a separate valve or access area for connection to the fluid source (not shown). When the bladder  251  is formed through the expansion of the tubing  350 , the tubing end (not shown) set opposite the pinch valve  320  is connected to a fluid source (not shown) and expanded, while the pinch valve  320  is set in the closed position, by the force of the entering fluid. In general, fluids such as water from a public source are delivered at a rate of 90 psi. Through the use of the tubing  350  as a bladder  251 , the bladder  251  controls the fluid rate of delivery, lowering the rate of delivery to approximately 40 psi, a rate in which the pinch valve  320  is operable through the use of only manual force. 
     The bladder  251  and tubing  350  act as a throttle enabling the use of manual force to control the flow of fluid entering the system at rates up to approximately 40 psi. The bladder  251  absorbs the differential between the source of the fluid and the pinch valve  320 . The self-contained nature of the present invention has many industry uses including, but not limited to, hospital, laboratory or other industries where the control of contamination is required. 
     The pinch blade  366  is positioned, when assembled, within outer housing  322  and is mounted therein for reciprocal movement between an open position permitting fluid flow through flexible tubing  350  and a close position preventing fluid flow. The pinch blade  366  is constructed on a frame  357  that is secured to the actuator  338 . An opening extends through the outer housing  322  and is adapted to receive one or more flexible tubings  350  therethrough. When in the open position, the arc segments  340  and  342  are in a relaxed position and secure the flexible tubing  350  within the outer housing  322 . The blade member  366  has a central plane substantially normal to the longitudinal axis of the flexible tubing  350  (when the valve is in the open position). 
     Coil spring  336  is disposed in pinch valve  320  between the actuator  338  and the frame  337 . The actuator  338  is compressible to at least the length of the outer diameter of the tubing  350  to ensure that the tubing  350  is fully inserted into the throat  352 . The spring strength is selected for the specific application. The specification thereof turns on the fluid pressure anticipated and the actuator pressure desired for initiating fluid flow. The actuator pressure needs to be ergonomically suited to the marketplace for the product. The construction of a restrictive channel or throat into which the blade member pushes the flexible tubing is the subject of design variations forming the basis for the various configurations expressed herein as separate embodiments. The best mode practice has hinged arc segments which, when flexed, form the receiving throat. 
     Upon completion of assembly, the pinch valve  320  is normally open, permitting fluid flow through flexible tubing  350 .  FIGS. 14 and 15  show the operative positions of the pinch valve of the first embodiment of this invention. Here  FIG. 14  shows the pinch valve  320  in the normally open condition and  FIG. 15  shows the pinch valve operated to the closed condition. In the closed condition, spring  336  is compressed urging the blade member  366  to crimp the flexible tubing  350  and urge the tubing into the throat  352 . In doing so, the tubing  350  flexes arc segments  340  and  342  causing the arc segments to press against tubing  350 . In this condition the pushbutton  338  is compressed. With light manual pressure (9 to 15 lbs) the blade member  366  is urged into the throat  352 . The use of flexible arc segments  340  and  342 , minimizes the force required to bend the tubing  350  by reducing the surface friction of the tubing  350  against the arc segments  340  and  342 . 
     In moving the pinch valve  320  to the open condition, pushbutton  338  is in a relaxed state. As the segments  340  and  342  relax, the flexible tubing  350  is released and is gently removed from the throat  352 . The flexible tubing  350  becomes and open conduit and fluid flow is initiated. Fluid flow continues so long as the pushbutton remains relaxed. 
     While certain novel features of this invention have been shown and described and are pointed out in the claims annexed hereto, the invention is not intended to be limited to the details put forth above, since it is understood that various omissions, modifications, substitutions and changes in the forms and details of the device illustrated and in its operation can be made by those skilled in the art without departing from the spirit of the present invention.