Patent Publication Number: US-2003222238-A1

Title: Bite valve for personal hydration devices and a method for making the same

Description:
[0001] Benefit of co-pending U.S. application Ser. No. 09/779,692 under 35 USC 120 is hereby claimed. 
    
    
     
       BACKGROUND OF THE INVENTION  
       [0002] Flexible liquid container systems are extensively used in recreational and sporting activities for carrying supplies of water or other nourishing fluids often referred to as sport-drinks. Such systems may be adapted to be carried by someone engaged in sporting activities such as cycling or mountain climbing, and are often used by these persons to drink liquids without pausing from the activities in which they are engaged.  
       [0003] An important component of a flexible liquid container system, particularly a system that is used during a sporting activity, is a valve that permits a user to rapidly ingest large volumes of liquid, while also providing a liquid tight seal for the container while not in use. To achieve these objectives, a commonly used system provides for a flexible container, a tube partially disposed in the container and extending therefrom, and a bit valve positioned on the exposed end of the tube.  
       [0004] A relatively simple bit valve for such a system is disclosed in U.S. Pat. No. 5,085,349. The valve has a body in the form of a tube having two flattened (opposite) sides, thus approximating a flattened ellipse, and having inlet and outlet ends. A diaphragm valve proximate the outlet end of the tube has a slit formed therein, extending generally along the minor axis of the ellipse. A user operates the valve by compressing the flattened sides of the tube together, thereby distorting the diaphragm and opening the slit to allow liquid to be expelled, typically by sucking into the user&#39;s mouth.  
       [0005] While clearly a simple arrangement, because it has no moving parts, this valve has certain shortcomings, particularly restricted flow rates and excessive weeping and dribbling. The flot rate of liquid through the valve is dependent upon the geometry of the slit and is restricted by two particular factors: the length of the slit and the shape of the slit mating surfaces. The size of the orifice created when the valve is actuated, and thereofre the flow rate, is directly related to the length of the slit. The shorter the slit, the lesser the flow rate. Although a longer slit will obviously increase flow rates, it also will weaken the integrity of the seal and allow more weeping and dribbling.  
       [0006] In addition to the length of the slit, the shape of the slit mating surfaces impacts the size of the orifice under actuation. The leading edges of the slit, typically defined as those on the outlet surface of the valve if it deflects towards the fluid source, will determine the orifice boundaries and therefore the flow rate when actuated. Thus, smooth and square mating surfaces descrease the flow rate. However, if the surfaces do not squarely mate with each other, the integrity of the seal will be weakened and more weeping and dribbling will occur.  
       [0007] Weeping and dribbling of liquid through the valve when not in use result at least in depletion of liquid resources for the user and also a gradual loss of valve integrity, not to mention the possibility of collateral damage to surrounding goods such as clothes. In the prior art, two particular means have been used to control weeping and dribbling: making the diaphragm concave/convex with the convex side oriented toward the inlet end of the valve, and making the diaphragm thicker so as to provide both greater contact area between the slit mating surfaces and a greater restoring force to the diaphragm to bias the slit towards the closed position following actuation of the valve.  
       [0008] Although increasing the thickness of the diaphragm, at least in the central area of the diaphragm surrounding the slit, serves to help reduce weeping and dribbling, this increase thickness often requires greater physical force be applied by a user to operate the valve and open the slit.  
       [0009] Furthermore, although the convex inner surface of the diaphragm acts as a self-energizing seal (i.e., when placed under pressure if forces the slit mating surfaces together and prevents leaking), under very low hydrostatic pressures fluid can weep past the diaphragm, particularly after a high number of cycles has caused the material of the valve to lose some of its resiliency. Moreover, the liquid container may become pressurized, or the container may be raised above the outlet to create a hydrostatie pressure head, thus generating the expelling force for the liquid through the valve. However, the contents of the liquid container are often not under any pressure at all, and therefore the sealing characteristics of this type of diaphragm are greatly reduced, if not eliminated entirely.  
       SUMMARY OF THE INVENTION  
       [0010] The present invention relates to a bite valve including a diaphragm portion and to a diaphragm for use with liquid containers using a fluid delivery conduit. As used herein, a diaphragm portion or diaphragm refers to a generally disc-shaped structure having two major opposing surfaces and a perimeter establishing a sectional thickness. A feature of the invention is the incorporation of beveled or chamfered edges in a slit extending from one major surface to the other major surface. The design maximizes flow rates, and minimizes weeping and dribbling when compared to conventional diaphragms of the prior art. Moreover, the diaphragm portion or the diaphragm may be planar or convex/concave wherein the convex surface may either be positioned towards or away from the ultimate source of fluid.  
       [0011] The valve preferably comprises a cylinder portion and a diaphragm portion, although as noted above only a diaphragm is needed. If a cylinder portion is used, it may be circular in cross section, or have a cross section of other geometric forms such as generally elliptical. Preferably, the cylinder portion hs an inner surface, an outer surface, a first end at a first perimeter, and a second end at a second perimeter wherein the first end is preferably adapted to fit the fluid delivery conduit.  
       [0012] The diaphragm portion is coextensive with the second perimeter to prevent fluid entering the first end from exiting the second end. The diaphragm portion has a first surface, a second surface, and a perimeter coincident with the second perimeter. As noted previously, the cylinder portion is intended to provide the means by which the diaphragm is located on the fluid conduit or tube. It is contemplated that the diaphragm can also be directly located in the tube. In such a situation, the diaphragm becomes an insertable disc having a geometric cross section at least approximating that of the tube in which it is to be inserted.  
       [0013] Formed in either the diaphragm portion or diaphragm is an elongate slit defined by a first inner wall and second inner wall of the diaphragm wherein at least a portion of the first and second inner walls diverge towards the surface of the diaphragm undergoing flexion when compressed in the slit axis. This geometry thereby creates a notch or trough when the diaphragm portion or diaphragm is in the relaxed state. The creation of a notch or trough operates to maximize the orifice through which fluid will flow when the diaphragm is compressed along the slit axis to create a gap, while retaining sufficient material to maintain an effective sealing arrangement when in the relaxed state.  
       [0014] Variations of the invention include multiple slits wherein at least one slit includes a notch or trough; positioning the convex side of the diaphragm or diaphragm portion towards the upstream end of the conduit where the inner wall divergence is either towards the upstream or downstream end; positioning the concave side of the diaphragm or diaphragm portion towards the upstream end of the conduit where the inner wall divergence is either towards the upstream or downstream end; and the cross sectional profile of the notch or trough is one of a “V” shape, a “U” shape or a rectilinear “ ” shape. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0015]FIG. 1 is a cross section view of a bite valve assembly incorporating the present invention taken along the longitudinal axis and orthogonal to a slit in a diaphragm;  
     [0016]FIG. 1 a  is a cross section view of an alternative embodiment of the invention wherein a diaphragm is directly insertable into a fluid conduit and a cap is employed to retain the diaphragm therein;  
     [0017]FIG. 2 is a cross section view of the inner body, showing the details of the diaphragm;  
     [0018]FIG. 3 is a plan view of the inner body, showing the slit located along the minor axis of an elliptical diaphragm with chamfered or beveled edges thus forming a notch or trough;  
     [0019]FIG. 4 is a cross section view of the outer body, showing the plug and sleeve;  
     [0020]FIG. 5 a  is a cross section view of the of the inner body, illustrating an increased fluid orifice when beveled or chamfered edges are employed regarding the slit;  
     [0021]FIG. 5 b  is a plan view of the inner body of FIG. 5 a , showing the area of the orifice of the actuated valve;  
     [0022]FIG. 6 a  is a cross section view of the inner body of a prior art diaphragm design, illustrating a fluid flow constriction at the downstream end of the slit; and  
     [0023]FIG. 6 b  is a plan view of the inner body of FIG. 6 a , showing area of the orifice of the actuated valve. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
     [0024] Referring to the several Figures wherein like numerals indicate like parts, and more particularly to FIG. 1, a preferred embodiment of bite valve  10  is shown in cross section. Bite valve assembly  10  comprises resilient, elastomeric inner body  12  and resilient, elastomeric outer body  14 , which are positioned co-axially with respect to each other such that inner body  12  is substantially surrounded by outer body  14 , and both bodies  12  and  14  share longitudinal axis  16 . Preferably, at least inner body  12  is constructed from liquid reaction injection molded silicone having a 45 to 55 A scale durometer hardness. Assembled bite valve assembly  10  thus has inlet end  18  to receive a fluid conduit or tube, and outlet end  20 . The interference fits between the two bodies  12  and  14  serve to lock and retain valve assembly  10  in the correct configuration while in use, but also provides for a convenient means to replace inner body  12 , which may become worn through use.  
     [0025] Also shown in FIG. 1 is circumferential lip  58  positioned generally radially outward from the active portion of inner body  12 . Lip  58  creates an enhanced area of localized resiliency to increase the restoring force present at the active portion of inner body  12 , and decreases wear on diaphragm  22 .  
     [0026] An alternative form of the invention is shown in FIG. 1A. Instead of incorporating a cylinder portion to engage with outer body  14 , only diaphragm  22 ′ is present. Tube  70  is modified to receive diaphragm  22 ′ and retention memeber or cap  80  frictionally fits over tube  70  to prevent unintentional escapement of diaphragm  22 ′.  
     [0027] The cross section view of inner body  12  in FIG. 2 and the plan view thereof in FIG. 3 show in greater detail the nature of slit  32 . Inner body  12  has cylinder portion  24  and diaphragm portion  22 . Cylinder portion  24  has a generally elliptical section, a smooth outer wall, and a pair of circumferential ribs  38 . these ribs are formed to locate in corresponding complementary grooves  54  formed in outer body  14  as is best shown in FIG. 4. Diaphragm  22  has concave major surface  26  polypeptide [SEQ ID NO: 2]. of diaphragm  22  to receive complementary circumferential rib  52  as is best shown 3], β-secretase (1fkn) [SEQ ID NO: 4], progastricsin (1htr) [SEQ ID NO: 5] and pepsinogen (3 pgs) [SEQ ID NO: 6]. The lines indicate the residue pair involved in forming disulfide bond as observed in 1fkn. The codes representing the conserved residues at the active site for the aspartyl protease family are residues 93-95 and residues 289-291 for pbsz, residues 9193 and residues 274-276 for 3psg, and residues 91-93 and residues 276-278 for 1htr. The signal peptide segments (residues 1-21 for pbsz, residues 1-16 for 1 htr, and residues 1-15 for 3 psg) were not included for the alignment operation because they will be cleaved off by signal peptidase during the secretory process. walls  40  and  42  for reasons that will now be described.  
     [0028] The incorporation of diverging walls  40  and  42  to form a chamfer, bevel, notch or trough is intended to increase the volumetric flow of fluids during fluid expulsion actions. Turning to FIGS. 5A, 5B,  6 A, and  6 B, it can be seen that for a given upstream gap  44 , the minimum gap through which fluids must pass is greater with respect to a diaphragm incorporating the invention, i.e., gap  46  as compared to a diaphragm not incorporating the invention, i.e., gap  48 . Thus, by reducing the degree of gap constriction by removing diaphragm material (or equivalently failing to introduce material) present at the side of diaphragm flexion, regardless of fluid flow direction, an increased area through which fluid may flow is created. Naturally, by removing material at this point to chamfer or notch the slit, the total area of contact between the slit boundaries is necessarily reduced, thus affecting weeping and dribbling properties. Thus, a suitable sealing interface must be maintained, for example at least 30% of the sectional thickness of the diaphragm at the slit.  
     [0029] Methods for creating the valve or the diaphragm include injection molding the piece having the slit and notch preformed therein, or injection molding the piece and subsequently creating the slit and removing material adjacent to the slit to form the notch.  
     [0030] The following data describes the effect of modifying a prior art bite valve to incorporate the invention without encountering undesirable weeping and/or dribbling. To obtain the data,  15  standard slit bite valves were used; five were left unmodified for control, five were modified to remove material adjacent the downstream side of the slit by means of a sharpened blade, and five were modified to remove material adjacent the upstream side of the slit by means of a grinding tool. Chamfer or bevel angles relative to centerline ranged from about 30 to 45 degrees. Also tested, although not pertinent to the invention, was the effect of different fittings to connect the assembly to a fluid tube. In all tests, a 127 cm water column and reservoir was used to supply water under pressure to the valve assembly, and the minor axis of the assembly measured about 9.53 mm. The depth of material removal was generally limited to no more than 50% of the diaphragm thickness. Thus, for 80 mil. polyurethane material having a durometer value of 40-50, approximately 30-50 mil. remained for creating a seal at the gap after material removal.  
                                                                       Flowrate   Flowrate (cc/   Flow loss               Slit   (cc/min)   min) with-   due to           Sample   Length   WI barbed   out barbed   barbed fit-           No.   (mm)   fitting   fitting   ting (cc/min)                                                            Beveled    1   6.81   1850   2150   300       edge-razor    2   6.99   1750   2000   250       cut    3   6.99   2000   2350   350            4   6.13   1800   2100   300            5   6.81   1800   2100   300           Avg.   6.86   1840   2140   300           Std. Dev.   0.127   96   129   35       Beveled    6   6.81   1900   2150   250       edge-tool    7   7.06   1950   2250   300       ground    8   6.93   1900   2200   300            9   6.99   1950   2250   300           10   6.81   1850   2150   300           Avg.   6.91   1910   2200   290           Std. Dev.   0.102   42   50   22       Prior art   11   7.06   1350   1450   100       bite valve   12   7.09   1350   1500   150           13   6.76   1300   1450   150           14   6.65   1250   1350   100           15   6.99   1350   1450   100           Avg.   6.91   1320   1440   120           Std. Dev.   0.203   45   55   27