Patent Publication Number: US-6712095-B2

Title: Vacuum demand valve

Description:
RELATED APPLICATIONS 
     This Application is a divisional of U.S. application Ser. No. 09/880,720, now U.S. Pat. No. 6,550,493, filed Jun. 13, 2001, which Application is incorporated herein by reference and made a part hereof, and upon which a claim of priority is based. 
    
    
     TECHNICAL FIELD 
     The present invention relates generally to valves used in conjunction with fluid containers or tubing, and more specifically to a vacuum demand valve associated with a fluid container or within a tubing. 
     BACKGROUND PRIOR ART 
     In the medical field, beneficial agents are often delivered to patients through polymeric tubing. When the quantity of the beneficial agents must be tightly, controlled, the beneficial agents are typically delivered intravenously via the tubing and regulated by a precision pump. Many times, however, the quantities of the beneficial agents introduced into the patient do not need to be tightly controlled. In these instances, the beneficial agents are typically introduced to the patient orally. 
     Oral administration of the beneficial agents is also accomplished via polymeric tubing. To transfer the beneficial agent from a container to the patient, one end of a length of tubing is brought into contact with the beneficial agent while the other end of the tubing is inserted into the patient&#39;s mouth. The patient then provides the vacuum pressure required to draw the beneficial agent from the container, through the tubing, and into the patient&#39;s mouth. 
     There are drawbacks associated with this method of delivery. For instance, patients are often sedated or medicated with drugs that cause drowsiness. Post-operative drowsiness caused by the effects of anesthesia is also a common occurrence. Thus, patients often drift into an involuntary unconscious state as a result of the drowsiness. This often occurs during oral administration of the beneficial agent where the patient is providing the vacuum pressure necessary to draw the beneficial agent from its container. 
     When the patient drifts into unconsciousness, the beneficial agent is typically spilled causing an undesirable waste. In addition, the mess caused by the spill must be attended to by hospital staff. Many times, the patient&#39;s gown must be changed; the bedding must be replaced; and the floor in the surrounding area must be mopped. This is very costly to the hospital as it depletes supplies and, more important, ties up hospital staff who ordinarily would be attending to more worthwhile tasks. 
     Similar problems are also experienced with fluid containers in general. For example, spillage problems are also associated with fluid containers commonly used to contain water, soft drinks, sports drinks, alcoholic beverages and the like. A suitable closure for such containers has not been developed that can address spillage problems while still being easy to use and economical to manufacture. Similar problems may also be experienced with other types of fluid containers used in industry and various mechanical arts such as engines and the like. For example, one is familiar with the problems arising with fluid spills in an industrial setting, wherein the spill of a caustic or dangerous chemical causes significant clean-up expense as well as placing workers in a potentially hazardous position. 
     The present invention is provided to solve these and other problems. 
     SUMMARY OF THE INVENTION 
     The present invention provides a vacuum demand valve capable of dispensing a flowable material. In one preferred embodiment, the vacuum demand valve is attached to fluid container. 
     It is an object of the present invention to provide a tubing comprising a valve member openable by an external force supplied by a user. The tubing generally comprises a sidewall, a proximal end, a distal end, an intermediate segment, and a valve member. The sidewall includes an inner wall and an outer wall. The inner wall defines a passageway adapted for transfer of a fluid substance. The intermediate segment is located between the proximal end and the distal end. The valve member is located along the intermediate segment and has a closed condition wherein a flow of the fluid substance from the proximal end to the distal end is stopped and an open condition wherein the fluid substance is allowed to flow from the proximal end to the distal end. The valve member is biased in the closed condition and is responsive to the external force provided by the user for placing the valve member in the open condition. 
     It is a further object of the present to provide a tubing having a valve member which includes a diaphragm. The valve member also includes a port and a plunger. The diaphragm is responsive to an external force supplied by the user, and a movement of the diaphragm in response to the external force places the valve member in an open condition. The plunger has a first end joined to the diaphragm and a second end extending from the lower surface of the diaphragm. The second end of the plunger substantially plugs the port when the valve member is in a closed condition. 
     It is a further object of the present invention to provide a tubing having a valve member which includes a pore. The pore has a dilating central portion. The dilating central portion is responsive to the external force and substantially sealed in the closed condition. The dilating central portion expands or widens to allow the flow of fluid substance to pass therethrough. 
     It is a further object of the present invention to provide a tubing having a valve member which utilizes a poppet, spool, or plunger. The valve member also includes a plunger housing. The plunger is located within the plunger housing and forms a substantially fluid-tight seal therewith. The plunger is slidable within the plunger housing in response to an external force provided by a user. 
     It is further an object of the present invention to provide a tubing having a valve member which includes a flexible bladder. The flexible bladder is responsive to the external force supplied by the user. In the closed condition, the flexible bladder forms a substantially fluid-tight seal with a portion of the valve member. The valve member also includes a retainer extending inwardly from the inner wall of the tubing. The retainer has flow holes to allow the fluid substance to flow therethrough. A portion of the bladder is joined to the retainer. 
     It is further an object of the present invention to provide a tubing having a valve member which includes a mechanical gate. The valve member has a port located within the passageway, a gate responsive to the external force provided by the user, a vacuum chamber, and a vent located within the vacuum chamber. The gate has a first portion separated from a second portion by a hinge member. The first portion is biased to form a substantially fluid-tight seal in the port. The second portion is biased to form the vacuum chamber within the passageway. The hinge member is moveably attached to a portion of the sidewall. 
     Other features and advantages of the invention will be apparent from the following specification taken in conjunction with the following drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of an embodiment of the invention attached to a fluid container; 
     FIG. 2 is a side view of the valve member of FIG. 1 in the closed condition; 
     FIG. 3 is a side view of the valve member of FIG. 1 in the open condition; 
     FIG. 4 is a perspective view of an embodiment of the invention attached to a fluid container; 
     FIG. 5 is a side view of the valve member of FIG. 4 in the closed condition; 
     FIG. 6 is a side view of alternate valve member utilizing a diaphragm in the closed condition; 
     FIG. 7 is a side view of the valve member of FIG. 4 in the open condition; 
     FIG. 8 is a perspective view of an embodiment of the invention; 
     FIG. 9 is a side view of the valve member of FIG. 8 in the closed condition; 
     FIG. 10 is a view of the valve member of FIG. 8 taken along A—A of FIG. 9; 
     FIG. 11 is a view of the valve member of FIG. 8 taken along B 1 —B 1  of FIG. 9; 
     FIG. 12 is a side view of the valve member of FIG. 8 in the open condition; 
     FIG. 13 is a view of the valve member of FIG. 8 taken along B 2 —B 2  of FIG. 12; 
     FIG. 14 is a perspective view of an embodiment of the invention attached to a fluid container; 
     FIG. 15 is a side view of the valve member of FIG. 14 in the closed condition; 
     FIG. 16 is a side view of the valve member of FIG. 14 in the open condition; 
     FIG. 17 is a perspective view of an embodiment of the invention attached to a fluid container; 
     FIG. 18 is a side view of the valve member of FIG. 17 in the closed condition; 
     FIG. 19 is a view of the valve member of FIG. 17 taken along A—A of FIG. 18; 
     FIG. 20 is a side view of the valve member of FIG. 17 in the open condition; 
     FIG. 21 is a perspective view of an embodiment of the invention attached to a fluid container; 
     FIG. 22 is a side view of the valve member of FIG. 21 in the closed condition; 
     FIG. 23 is a side view of the valve member of FIG. 21 in the open condition; 
     FIG. 24 is a perspective view of an embodiment of the invention attached to a fluid container; 
     FIG. 25 is a side view of the valve member of FIG. 24 in the closed condition; and 
     FIG. 26 is a side view of the valve member of FIG. 24 in the open condition. 
    
    
     DETAILED DESCRIPTION 
     While this invention is susceptible of embodiments in many different forms, there are shown in the drawings and will herein be described in detail, preferred embodiments of the invention with the understanding that the present disclosures are to be considered as exemplifications of the principles of the invention and are not intended to limit the broad aspects of the invention to the embodiments illustrated. 
     Referring initially to FIGS. 1-26, a vacuum demand valve of present invention is disclosed, generally referred to with the reference numeral  10 . In one preferred embodiment, the valve  10  may be embodied in a tubular structure and may be referred to as a tubing  10 . The valve or tubing  10 , which in one embodiment, could be a medical tubing  10 , generally comprises an elongated sidewall  12 , a proximal end  14 , a distal end  16 , an intermediate segment  18 , and a valve member  20 . The tubing  10  can generally be considered a housing of the valve. The elongated sidewall  12  has an inner wall  22  which defines a passageway  24  through which a flow of a flowable material, or fluid substance can travel. The intermediate segment  18  joins the proximal end  14  with the distal end  16 . The distal end  16  is adapted for insertion into a user&#39;s mouth while the proximal end  14  is generally adapted for connection to a container. In one embodiment, the container can be a polymeric medical container  20  as shown, for example, in FIG.  1 . It is understood, however, that the proximal end  14  can be connected to a further length of a medical tubing or inserted directly into a fluid carrying container without departing from the spirit of the present invention. It should further be understood that the valve members  20  disclosed herein may be integrated directly with a fluid container. It should further be understood that the valves or components thereof disclosed herein may be produced from a flexibly polymeric material, such as the polymeric materials that are typically used in the production of medical tubing and containers. 
     The valve member  20  is generally located within the intermediate segment  18  of the tubing  10  and regulates the flow of the fluid substance through the passageway  24  from the proximal end  14  to the distal end  16 . The valve member  20  is biased in a closed condition (shown in, for example, FIG. 2) wherein the flow of the fluid substance through the passageway  24  is blocked or stopped by a portion of the valve member  20 . An external force provided by a user actuates the valve member  20  from the closed condition to an open condition (shown, for example, in FIG. 3) so that an obstruction or restriction is removed from the passageway  24 , and the fluid substance is allowed to flow through the demand valve  10  or tubing  10 . The external force applied can be a partial vacuum pressure applied through the passageway  24 . The vacuum pressure is preferably applied by the user drawing inward on the distal end  16  of the medical tubing, by mouth, similar to the manner in which a person would use a straw. Alternatively, it is also contemplated that the user may provide a positive force to a portion of the valve member  20  which would transfer the valve member  20  from the closed condition to the open condition. In either case, when the external force is removed from the valve member  20 , the obstruction or restriction is restored, and the valve member  20  automatically returns to the closed condition. It is further understood that the partial vacuum can also be applied by a syringe, a pump, or other mechanical means. 
     The biasing of the valve member  20  is particularly beneficial. When the user requires a flow of the fluid substance, for example water, medicine, or any flowable material or the like, the user applies the external force to a portion of the valve member  20  to actuate the flow through the passageway to the user&#39;s mouth. Once the external force is interrupted, the flow is stopped. This is useful because for example, in a medical setting, patients can fall asleep during the administration of the fluid substance. If the flow is not automatically interrupted, it can continue to flow through the passageway  24 . Thus, the fluid substance is wasted, and a mess is created which often requires the user&#39;s gown to be changed, the bedding to be changed, and/or the floor in the surrounding area to be mopped. These occurrences can tie up costly hospital resources or simply be a housekeeping nuisance. 
     Referring to FIGS. 1-3, one form of the vacuum demand valve  10  is disclosed. The valve has a valve member  20  which utilizes a diaphragm  30 . In this embodiment, the valve member  20  comprises a flexible diaphragm  30 . The valve  10  further has a housing  11  having first and second retainers  32 , 34 , or upper and lower retainers  32 ,  34 . The retainers  32 , 34  are spaced to define an intermediate chamber  31  in the housing  11 . A vent hole  38  is provided in the housing. The housing  11  has an outlet chamber  23  defining an outlet opening  25 . The housing  11  further has an inlet chamber  27  defining an inlet opening  29 . The valve  10  further has a plunger  36 . The flexible diaphragm  30  is responsive to the external force provided by the user to acuate the valve member  20  from the closed condition (shown in FIG. 2) to the open condition (shown in FIG.  3 ). 
     The flexible diaphragm  30  extends inwardly into the passageway  24  from the inner wall  22  of the sidewall  12  and into the intermediate chamber  31 . The diaphragm  30  has an upper surface  40  and a lower surface  42 . An outer peripheral portion  44  of the flexible diaphragm  30  is attached to the inner wall  22  so that the flexible diaphragm  30  is moveable either downstream towards the proximal end  14  or upstream towards the distal end  16 . The flexible diaphragm  30  has a central opening  43  through which the plunger  36  is inserted. The flexible diaphragm  30  is fixedly connected to the plunger  36  so that the movement of the flexible diaphragm  30  either upstream or downstream is transferred directly to the plunger  36 . 
     The upper retainer  32  is located upstream of the flexible diaphragm  30  toward the distal end  16 . The upper retainer  32  extends inwardly into the passageway  24  from the inner wall  22  of the sidewall  12  of the housing and has an upper surface  46  and a lower surface  48 . The plunger  36  passes through a central opening  50  in the upper retainer  32 . The plunger  36  is slidable within the central opening  50 ; however, at least a substantially fluid-tight seal is formed between the plunger  36  and the central opening  50 . 
     The vent  38  is located between the flexible diaphragm  30  and the upper retainer  32 . The vent  38  passes through the sidewall  12  of the medical tubing  10  and allows a positive pressure to build between the upper retainer  32  and the flexible diaphragm  30 , thus actuating the valve member  20  from the closed condition to the open condition. 
     The lower retainer  34  is located downstream of the flexible diaphragm  30  toward the proximal end  14 . The lower retainer  34  is similar to the upper retainer  32 . Accordingly, the lower retainer  34  extends inwardly into the passageway  24  from the inner wall  22  of the sidewall  12  of the medical tubing  10  and has an upper surface  52  and a lower surface  54 . The plunger  36  passes through a central opening  56  in the lower retainer  34 . The plunger  36  is slidable within the central opening  56  of the lower retainer  34 , and at least a substantially fluid-tight seal is formed between the plunger  36  and the central opening  56 . 
     The plunger  36  is generally an elongated cylindrical member having first and second ends  58 ,  60 , a portion of each is disposed within the central openings  50 ,  56  of the upper and lower retainers  32 ,  34  respectively. The second end  60  includes a head portion  62  which acts as a stop to prevent the second end  60  from being completely withdrawn from the lower retainer  34 . 
     The plunger  36  also includes a fluid flow through passage  64  and a vacuum passage  66 . The flow through passage  64  acts as a port which transfers the fluid substance from the proximal end  14  through the plunger  36  to the distal end  16  of the medical tubing  10 . Accordingly, the flow through passage  64  has an outlet  68  located at the first end  58  of the plunger  36  and an inlet  70  located at the second end  60  of the plunger  36 . The inlet  70  is sealed against or obstructed by a portion of the lower retainer  34 , or second retainer  34 , when the valve member  20  is in the closed condition. 
     The vacuum passage  66  transfers a vacuum pressure provided by the user through the plunger  36  to a vacuum chamber  72 . The vacuum passage  66 , thus, has an inlet  74  located at the first end  58  of the plunger  36  and an outlet  76  located within the vacuum chamber  72 . 
     In use, the user draws in on the distal end  16  of the medical tubing  10 . The vacuum pressure created by the drawing in action is transferred through the vacuum passage  66  to the vacuum chamber  72 . As shown in FIG. 3, the flexible diaphragm  30  is drawn downstream towards the proximal end  14  of the medical tubing  10 . The plunger  30  moves downstream with the diaphragm  30  so that the inlet  70  of the fluid flow through passage  64  is released from the seal created with a portion of the lower retainer  34 , and the fluid substance is free to flow from the proximal end  14  to the distal end  16  via the fluid flow through passage  64 . When the vacuum pressure is released, the diaphragm  30  returns to its original position, and the fluid flow through passage  64  is resealed against a portion of the lower retainer  34 . 
     It is understood that with the vent  38 , the diaphragm  30  is subject to an index pressure PI. In one form of the invention, the index pressure PI could be ambient pressure. A partial vacuum, represented by a pressure P 2  (FIG.  3 ), can be applied by a user to draw the diaphragm  30  and open the valve  10 . 
     A second embodiment of the valve  10  or tubing  10  is illustrated in FIGS. 4-7. This embodiment also comprises a flexible diaphragm. The flexible diaphragm of this embodiment differs from the flexible diaphragm of the first embodiment in that it can be actuated by an external force provided by the user which takes the form of a vacuum pressure or, alternatively, a positive pressure. 
     The valve  10  has a housing  81  defining a passageway between an outlet opening and an inlet opening. The housing has an inner wall  83 . The valve member  20  of this embodiment includes a port  80 , or inner opening  80  through the inner wall. The inner wall  83  divides the passageway into a first chamber and a second chamber. The valve  10  also has a spring-loaded diaphragm  82  that fits within an aperture of the housing. The diaphragm  82  is responsive to an external force provided by the user, and a plunger  84 . The port  80  is positioned between the proximal end  14  and the distal end  16  of the medical tubing  10  and is the portion of the valve member  20  through which the fluid substance must travel to be delivered to the user. 
     The diaphragm  82  has an upper surface  86  and a lower surface  88  and is mounted within an aperture  90  formed in the sidewall  12  of the medical tubing so that a fluid-tight seal is formed between an outer peripheral portion  92  of the diaphragm  82  and the sidewall  12 . The diaphragm  82  is dome-shaped. A portion of the diaphragm  82  extends inwardly into the passageway  24  from the inner wall  22  of the sidewall  12  of the medical tubing  10 . The diaphragm  82  is moveable inwardly from the sidewall  12  and into the passageway  24  in response to either a vacuum pressure provided by the user by withdrawing on the distal end  16  of the medical tubing  10  or by providing a positive pressure to the upper surface  86  of the diaphragm  82  with, for example, the user&#39;s fingers. 
     The plunger  84 , or stop, extends inwardly from the lower surface  88  of the diaphragm  82  into the passageway  24 . In this embodiment, the plunger  84  is integral with the diaphragm  82  so that it is actually a portion of the diaphragm  82 . Thus, the movement of the diaphragm  82  is transferred to the plunger  84 . The diaphragm  82  is biased so that a portion of the plunger  84  at least substantially seals the port  80  so the fluid substance cannot flow therethrough. 
     The plunger  84  is generally an elongated cylindrical member having first and second ends  94 ,  96 . The plunger is tapered along its length. The second end  96  includes a head portion  98  which acts as a stop, plug, obstruction, or restriction within the port  80  to prevent the flow of fluid substance from flowing through the port  80  when the valve member  20  is in the closed condition. 
     In use, when a user desires the fluid substance to be delivered to his/her mouth, the user can draw inward on the distal end  16  of the medical tubing  10 . An outer surface of the diaphragm may be subject to an index pressure. In one preferred embodiment, the index pressure may be ambient pressure. A partial vacuum, represented by P 2  in FIG. 7, acts on a portion of the diaphragm  82 . The diaphragm  82  is deflectable inwardly from the sidewall  12  into the passageway  24 . Likewise, the plunger  84  moves inwardly and the stop, plug, obstruction, or restriction is removed from the port  80 , and the fluid substance is allowed to flow therethrough. 
     Alternatively, the user can provide a positive pressure to the upper surface  86  of the diaphragm  82 . The positive pressure forces the diaphragm  82  inwardly into the passageway  24 . Again, the plunger  84  is forced inwardly, and the stop, plug, obstruction, or restriction is removed from the port  80 , and the fluid is allowed to flow therethrough. 
     FIG. 6 shows a slightly alternative embodiment of the diaphragm  82  and the inner wall  83 . The inner opening of the inner wall  83  has a tapered inner surface. The diaphragm  82  has a stop having a curved peripheral surface. This surface is spaced from the tapered inner surface of the opening when the diaphragm  82  is in the second position or deflected position. 
     Another embodiment of the valve  10  is illustrated in FIGS. 8-13. In this embodiment, the valve member  20  comprises a duckbill mechanism. The valve member  20  of this embodiment may also be placed in the open condition either via a vacuum pressure or a positive pressure exerted on the sidewall  12  of the medical tubing  10 . 
     The valve member  20  of the embodiment of FIGS. 8 through 13 comprises a pore member  100 . The pore member  100  has a central portion  102  which dilates when the valve member  20  is in the open condition. The central portion  102  is at least substantially sealed in the closed condition and responsive to the external force provided by the user wherein the dilating central portion  102  expands to allow the flow of fluid substance to pass therethrough. 
     The central portion  102  includes an inwardly tapered, flexible duckbill  104 . The inwardly tapered, flexible duckbill  104  has a hinge portion  106  joined to the sidewall  12  of the medial tubing  10  and a separable slit  108  located within the passageway  24  and apart from the inner wall  22 . The separable slit  108  is at least substantially sealed when the valve member  20  is in the closed condition. The valve member  20  is responsive to a deflection in the sidewall to open the valve member. 
     The hinge portion  106  is responsive to an external force applied by a user to the sidewall  12  and preferably in an area proximate the hinge portion  106 . When the external force is applied, a portion of the inwardly, tapered flexible duckbill  104  is displaced inwardly into the passageway  24 . The separable slit  108  parts to allow the flow of fluid substance to pass therethrough. 
     To operate the valve member  20  by a vacuum pressure, the user applies a vacuum pressure to the distal end  16 . A pair of support members  110  extend upstream from the valve member  20  towards the distal end  16  of the tubing  10 . The support members  110  act as spacers to prevent the tubing  10  from collapsing on itself in response to a vacuum pressure supplied by the user to the distal end  16 . The vacuum pressure causes the sidewalls  12  to collapse and, in turn, causes the separable slit  108  to open to allow the flow of fluid as shown in FIG.  12 . 
     Further, the valve member  20  is positioned in the passageway in an intermediate portion of the housing. A first support member attached to the inner sidewall surface and extends along a portion of the housing. The support member is coactive with the deflection of the sidewall to control the opening of the valve member. The support member comprises a rib. The rib extends from proximate the proximal end to proximate the valve member. The valve  10  could also have a second support member. The housing can have a substantially circular cross-sectional shape and wherein the second support member is circumferentially spaced from the first support member. The rib can have a generally arcuate longitudinal-sectional shape. The rib increases in height from a minimum height to a maximum height and wherein the maximum height is proximate the proximal end. The rib has lateral edges that taper inwardly and upwardly as the rib extends away from the inner sidewall. The rib is effective to prevent the housing from fully collapsing. 
     Another embodiment of the valve  10  is illustrated if FIGS. 14-16. This embodiment also comprises valve member  20  having a duckbill mechanism. The valve  10  also has a slidable member mounted for reciprocating movement within the housing. Thus, the valve member  20  comprises a pore member  112 . The pore member  112  has a central portion  114  which opens by dilating. The central portion  114  is at least substantially sealed in the closed condition and responsive to the external force provided by the user wherein the dilating central portion  114  expands to allow the flow of fluid substance to pass therethrough. 
     The central portion  114  includes an inwardly tapered, flexible duckbill  116 . The inwardly tapered, flexible duckbill  116  has a hinge portion  118  joined to the sidewall  12  and a separable slit  119  located within the passageway  24  and apart from the inner wall  22 . The separable slit  119  is at least substantially sealed when the valve member  20  is in the closed condition. 
     The valve member  20  further comprises a piston  120  and a vent hole  122 . The piston  120  is at least substantially sealed against the inner wall  22  of the medical tubing  10  and slidable within the passageway  24  in response to the external force provided by the user. The vent hole  122  is located between piston  120  and the pore member  112  and passes through the sidewall  12  of medical tubing  10 . A hydrophobic filter  123  is located within the vent hole  122  to prevent the fluid substance from leaking out of the medical tubing  10  through the vent hole  122 . 
     The piston  120  includes a central chamber  124 , a retainer  126 , a tubular member  128 , and an elastic member  130 . The central chamber  124  passes through an interior portion of the piston  120  and includes inwardly tapered walls  132 . The inwardly tapered walls  132  cooperate with the inwardly tapered, flexible duckbill  116  to seal the separable slit  118  when the valve member  20  is in the closed condition. Thus, the tapered, flexible duckbill  116  fits snug within the central chamber  124  so that the central chamber  124  provides a force for maintaining the separable slit  118  at least substantially sealed. 
     The retainer  126  is located upstream of the central chamber  124  towards the distal end  16  of the medical tubing  10 . The retainer  126  extends inwardly from the inner wall  22  of the sidewall  12  into the passageway  24  and includes a plurality of flow holes  134  and a central hole  136 . The purpose of the retainer  126  is to support the tubular member  128  within the passageway  24 . 
     The tubular member  128  has a first end  138  and a second end  140 . The first end  138  is frictionally supported by the central hole  136  of the retainer  126  and slidable therethrough. The second end  140  is fixedly attached to the piston  120 . In the open condition, the fluid substance travels through the inwardly tapered, flexible duckbill  116 , the central chamber  124 , and the tubular member  128 . 
     The elastic member  130  provides a biasing force on the piston  120  so that the separable slit  118  is at least substantially sealed within the central chamber  124 . The elastic member  130  is preferably a spring wound about the tubular member  128  and compressible against the retainer  126 . 
     The valve  10  further has a slidable member  133  mounted for reciprocating movement within the housing and in response to a pressure applied to the housing. The slidable member is moveable from a first position contacting the valve member to retain the valve member in a closed position to a second position where the valve member moves to the open position. The slidable member defines a fluid flow path therethrough. The elastic member  130  biases the slidable member in a first position. The slidable member has a seal having a chamber for engaging a portion of the valve member. The duckbill valve member has a sloping outer surface. The seal has a chamber having inwardly tapered walls dimensioned to fit over the duckbill valve sloping outer surface. 
     In use, the user draws inwardly on the distal end  16  so that a vacuum pressure is created within the passageway  24 . The vacuum pressure passes through the flow holes  134  in the retainer  126  and causes the piston  120  to move upstream towards the distal end  16  against the biasing force provided by the elastic member  130 . The sealing force provided by the central chamber  124  on the separable slit  118  is removed, and the flow of the fluid substance travels from the proximal end  14  through the pore member  112 , the central chamber  124 , and the tubular member  128  to the distal end  16 . 
     Another embodiment is illustrated in FIGS. 17-20. In this embodiment, the valve member  20  includes a flexible bladder  140 . The flexible bladder  140  is responsive to a vacuum pressure provided by the user to the distal end  16  of the medical tubing  10 . The valve  10  has a housing  11  having an inner surface defining a passageway between an outlet opening and an inlet opening for a flowable material to pass therethrough. 
     The valve member  20  of this embodiment comprises the flexible bladder  140 , a retainer  144 , and a support member  146 . The flexible bladder  140  is generally a pressurized vessel which elongates in response to the vacuum pressure provided by the user to actuate the valve member  20  and transfer the valve member  20  to the open condition. The flexible bladder  140  is deflectable to be spaced away from the inner wall  22 . The flexible bladder  140  includes a sealing ring portion  148  which forms at least a substantially fluid-tight seal in cooperative engagement with a portion of the inner wall  22  of the medical tubing  10  when the valve member  20  is in the open condition. A stem  150  for attaching the flexible bladder to the retainer  144  extends downstream toward the proximal end  14  of the medical tubing  10 . 
     The retainer  144  is located downstream of the flexible bladder  140  and extends inwardly from the inner wall  22  of the medical tubing  10  into the passageway  24 . A plurality of flow holes  152  in the retainer  144  allow the flow of fluid substance to pass through the retainer  144 . The stem  150  of the flexible bladder  144  is attached to a central portion of the retainer  144 . 
     The support member  146  prevents the flexible bladder  44  from over-elongation towards the distal end  16  and prevents the distal end  16  of the medical tubing  10  from collapsing on itself in response to the vacuum pressure provided by the user Accordingly, the support member  146  extends along a length of the inner wall  22  from the flexible bladder  144  to the distal end  16 . The support member  146  generally comprises a plurality of ribs  154  extending inwardly from the inner wall  22  wherein a cross-sectional area of the passageway  24  is decreased by the plurality of ribs  154 . 
     Another embodiment is illustrated in FIGS. 21-23. In this embodiment, the valve member  20  includes a poppet, spool, or plunger  160 . The plunger  160  is responsive to a vacuum pressure provided by the user. The valve member  20  of this embodiment further comprises a plunger housing  162  and a vent hole  164  passing through the sidewall  12  of the housing. 
     The plunger  160  is mounted within the plunger housing  162  and is slidable therein. The plunger  160  has a fluid passage  166  which is obstructed so that it is at least substantially sealed against a portion of the plunger housing  162  when the valve member  20  is in the closed condition. The fluid passage  166  is unobstructed and aligned with the passageway  24  to allow the flow of fluid substance to pass therethrough when the valve member  20  is in the open condition. 
     The plunger housing  162  includes a vacuum chamber  168  and a vent chamber  170 . An elastic member  172  is generally mounted within the vacuum chamber  168  to bias the plunger  160  towards the vent chamber  168  wherein the fluid passage  166  is obstructed against a portion of the plunger housing  162 . The elastic member  172  is preferably a compression spring. The vent hole  164  is located within the vent chamber  168 . 
     The distal end  16  of the tubing of this embodiment includes a vacuum duct  174  and a fluid duct  176 . The vacuum and fluid ducts  174 ,  176  are located within the passageway  24  between the valve member  20  and along a length of the distal end  16 . The fluid passage  166  of the plunger  160  is aligned with the fluid duct  176  when the valve member  20  is in the open condition. The vacuum duct  174  is aligned with the vacuum chamber  168 . 
     The housing  162  may have a first fluid conduit in fluid communication with the housing. The plunger  160 , or valve member  160  is mounted for reciprocating movement within the housing. The valve member  162  defines a second fluid conduit therethrough. The valve member  162  is moveable from a first position where the first fluid conduit is substantially concentrically disposed with respect to the second fluid conduit to provide a third fluid conduit (FIG. 23) through the housing to a second position where the first fluid conduit is not in fluid communication with the second fluid conduit (FIG.  22 ). The vacuum duct  174 , or vacuum conduit  174  is in fluid communication with the housing. 
     In this embodiment, the external force provided by the user is a vacuum pressure. The vacuum pressure is applied through the vacuum duct  174 . The vacuum pressure causes the plunger  160  to compress the elastic member  172  and the fluid passage  166  is aligned with the passageway  24  so that the flow of the fluid substance can travel through the tubing to the user. Thus, the valve member  160  is responsive to a negative pressure applied to the housing through the vacuum conduit to move the valve member from the second position to the first position. A biasing member  172  in the form of a spring biases the valve member  160  in the second position. The valve member  160  divides the housing into an expansion chamber and a vacuum chamber. The vacuum duct is in fluid communication with the vacuum chamber. 
     Another embodiment is illustrated in FIGS. 24-26. In this embodiment, the valve member  20  includes a mechanical gate mechanism  180  responsive to an external force provided by the user. The valve  10  has a housing defining a passageway between an outlet opening and an inlet opening for a flowable material to pass therethrough. The housing has an inner surface. 
     The valve member  20  of this embodiment further comprises a port  182 , a vent hole  184  passing through the sidewall  12  of the tubing, and an elastic member  186 . The vent hole  184  includes a hydrophobic filter  188 . 
     The gate  180  includes a first portion  190  and a second portion  192 . In the closed condition, the first portion  190  forms at least a substantially fluid-tight seal in the port  182 , and the second portion forms at least a substantially fluid-tight seal with the inner wall  22  of the medical tubing  10  so that a vacuum chamber  194  is formed. The vent hole  184  is located within the vacuum chamber  194 . 
     The first and second portions  190 ,  192  of the gate  180  are separated by a hinge member  196 . The hinge member  196  is pivotably attached to a portion of the sidewall  12 . Accordingly, the hinge member  196  is attached to the sidewall  12  at a fulcrum  198  which extend inwardly from the inner wall  22  into the passageway  24 . 
     The elastic member  186  is for biasing the gate  180  so that the valve member  20  is biased in the closed condition. The elastic member  186  is fixedly attached to the second portion  192  of the gate  180  and the inner wall  22  of the medical tubing  10 . Thus, the elastic member  186  of this embodiment is preferably a return spring. 
     In use, the user draws inwardly on the distal end  16  of the medical tubing  10 . The vacuum pressure causes the second portion  192  of the gate  180  to move upstream towards the distal end  16  and against the biasing force provided by the elastic member  186 . Thus, the gate  180  pivots upon the fulcrum  198 . The valve member  20  is, thus, in the open condition where the first portion  190  moves downstream towards the proximal end  12 , and the seal in the port  182  is released so the flow of the fluid substance can pass through the passageway  24 . When the vacuum pressure is removed, the gate  180  returns to its original position, and the valve member  20  returns to the closed condition. 
     The valves  10  of the present invention have a broad variety of uses and applications. The valve  10  is ideal for using with hot or cold drinks, as well as non-carbonated drinks. The valves  10  can be connected to a drink container. Users can easily carry such a container on their person. Containers holding, for example, juice or milk, can also be used for children and infants. The containers can also have a hanger member to hang a container using a valve  10 . The containers can be used in a number of different recreational settings. The containers are also ideal when taking part in active sporting activities. Uses also comprehended by the scope of the invention include storage and dispensing of industrial chemicals, medicaments or any other flowable material. 
     It will be understood that the invention may be embodied in other specific forms without departing from the spirit or central characteristics thereof. The present embodiments, therefore, are to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given herein.