Abstract:
A non-return valve ( 10 ), typically of commonly called duckbill valve shape, comprising a valve body ( 12 ) and a valve membrane ( 14 ). The valve body ( 12 ) is generally tubular and includes an elongate passageway ( 16 ) with inlet ( 18 ) and outlet ( 20 ) at opposing ends. The valve membrane ( 14 ) is of a generally conical-shaped diaphragm formed integrally with the valve body ( 12 ). The diaphragm ( 14 ) has a collapsible opening or aperture ( 22 ) located at or adjacent the cones apex. The conical diaphragm ( 14 ) is oriented with its apex pointing downstream. The resiliently flexible material from which the diaphragm ( 14 ) is constructed, ensures that the diaphragm ( 14 ) in a collapsed condition obstructs or closes the aperture ( 22 ) to prevent fluid flowing in a reverse direction, i.e. backflow towards the inlet. Pressurisation of fluid within the passageway ( 16 ) on the inlet ( 18 ) side of the diaphragm ( 14  ), deflects the diaphragm to open the aperture ( 22 ) so that fluid can flow through the passageway from the inlet ( 18 ) to the outlet ( 20 ) only. A membrane permeable in one direction only can also be made from a panel or sheeting incorporating many such collapsible non-return duckbill valves on the surface of the panel or sheet.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates generally to a non-return valve such as that used on a pneumatic tyre, and a membrane being permeable in one direction only.  
         BACKGROUND TO THE INVENTION  
         [0002]    Non-return valves are common in industrial and domestic applications and are particularly prolific on pneumatic tyres. FIG. 1 illustrates the various components of a conventional pneumatic non-return valve  1 . The valve  1  comprises an inlet casing  2  which is screw threaded within a valve stem of a tyre (not shown). The inlet casing  2  houses a shaft  3  along which a valve member  4  slidably moves. The valve member  4  is biased against a seat  5  of the casing  2  under the force of a compression spring  6  so as to close the valve  1 . A spring retainer  7  is connected to an end of the shaft  3  so as to retain the compression spring  6 . Pressurisation of the non-return valve  1  releases the valve member  4  from the seat  5  to allow filling of the tyre.  
           [0003]    The conventional pneumatic non-return valve  1  suffers from at least the following problems:  
           [0004]    i) the valve  1  has a relatively large number of components which may require periodic servicing and maintenance;  
           [0005]    ii) the valve  1  is expensive including relatively complex machined components; and  
           [0006]    iii) the valve is complicated in operation and thus in operation may be susceptible to failure.  
         SUMMARY OF THE INVENTION  
         [0007]    According to one aspect of the present invention there is provided a non-return valve comprising:  
           [0008]    a valve body including a fluid passageway which defines a fluid inlet and a fluid outlet located on a low pressure and a high pressure side of the valve, respectively, the fluid passageway being adapted to allow a flow of fluid from the inlet to the outlet; and  
           [0009]    a valve diaphragm in the form of a conical-shaped diaphragm having a collapsible aperture located at or adjacent its apex which is orientated in a downstream flow direction and directed toward the high pressure side of the valve, said diaphragm being connected across the fluid passageway and being constructed of a resiliently flexible material wherein the diaphragm itself initiates closure of the collapsible aperture, said closure being further promoted by fluid on the high pressure side of the valve to thus prevent fluid flowing in a reverse direction toward the inlet whereas the application of pressure, exceeding atmospheric pressure and that on the high pressure side, to an inlet side of the diaphragm deflects the diaphragm to expose the aperture and allow fluid to flow through the passageway from the inlet to the outlet only.  
           [0010]    Typically the pressure is imposed on the inlet side of the diaphragm via a fluid nozzle which is designed to be retractably received within the passageway.  
           [0011]    Generally the fluid is a liquid such as petrol and the non-return valve serves to prevent a reverse flow or escape of vapours.  
           [0012]    Preferably the valve body is designed to fit to a reservoir or tank in which fluid is to be dispensed via the fluid nozzle. For example, the non-return valve is configured to fit to a petrol tank.  
           [0013]    According to a further aspect of the present invention there is provided a non-return valve including a bank or series of non-return valves of similar construction coupled to one another, each of said non-return valves comprising:  
           [0014]    a valve body including a fluid passageway which defines a fluid inlet and a fluid outlet, the fluid passageway being adapted to allow a flow of fluid from the inlet to the outlet; and  
           [0015]    a valve diaphragm being connected across the fluid passageway and including a collapsible aperture, the valve diaphragm being constructed of a resiliently flexible material and being configured wherein the diaphragm itself in a collapsed condition effects closure of the collapsible aperture to prevent fluid flowing in a reverse direction toward the inlet whereas pressure imposed on an inlet side of the diaphragm deflects the diaphragm to expose the aperture and allow fluid to flow through the passageway from the inlet to the outlet only.  
           [0016]    Generally the non-return valves are coupled together with their respective valve bodies at least partly nested within one another wherein said valves are co-axially aligned. Alternatively the non-return valves are each of the same construction and configured to abut or engage one another with their valve bodies in alignment.  
           [0017]    Preferably each of the diaphragms is formed integral with the corresponding valve body. More preferably the diaphragms are each in the form of a generally conical-shaped diaphragm having the collapsible aperture located at or adjacent its apex which is orientated in a downstream flow direction.  
           [0018]    Generally said actuating means is a fluid nozzle which is retractably inserted into at least one of the collapsible apertures to permit a flow of fluid across the corresponding diaphragm via the fluid nozzle.  
           [0019]    Preferably the valve membrane is formed integral with the valve body.  
           [0020]    Typically the valve membrane is constructed of a mouldable polymeric material. More typically the polymeric material is an elastomer such as a rubber material. Alternatively the polymeric material is a nylon-based material.  
           [0021]    Preferably the valve body is configured to retrofit to an existing valve stem. Alternatively the valve body is designed to be sealably inserted into a flow line.  
           [0022]    Generally the fluid is water or compressed air.  
           [0023]    According to yet a further aspect of the present invention there is provided a membrane being permeable in one direction only, said membrane comprising a panel or blanket of collapsible diaphragms each including a collapsible aperture and being constructed of a resiliently flexible material which is configured wherein each of the diaphragms themselves effects closure of the collapsible aperture to prevent fluid flowing in a reverse direction whereas pressure imposed on an upstream side of the membrane deflects one  6 r more of the diaphragms to expose the corresponding aperture and allow fluid to flow across the membrane in said one direction only.  
           [0024]    Generally the membrane is multi-layered with a series of said panels or blankets formed adjacent one another. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0025]    In order to facilitate a better understanding of the nature of the present invention several embodiments of a non-return valve and a membrane being permeable in one direction only will now be described, by way of example only, with reference to the accompanying drawings in which:  
         [0026]    [0026]FIG. 1 is a general assembly of a conventional pneumatic non-return valve;  
         [0027]    [0027]FIG. 2 illustrates three stages in the general assembly of a non-return valve according to one embodiment of the invention;  
         [0028]    [0028]FIG. 3 is a general assembly of another embodiment of the invention suitable for use with irrigation tubing;  
         [0029]    [0029]FIG. 4 is a general assembly of a further embodiment of a non-return valve of the invention suitable for use in pneumatic tyres;  
         [0030]    [0030]FIG. 5 is an assembly of a non-return valve of yet another embodiment of the invention suitable for tubeless pneumatic tyres;  
         [0031]    [0031]FIG. 6 is a general assembly of a non-return valve of another aspect of the invention;  
         [0032]    [0032]FIG. 7 is an elevational and part cutaway view of a tool suitable for moulding of the non-return valve;  
         [0033]    [0033]FIG. 8 is a part cutaway together with an enlarged view of the tool of FIG. 7;  
         [0034]    [0034]FIG. 9 is sectional views of the tool of FIGS. 7 and 8;  
         [0035]    [0035]FIG. 10 illustrates three embodiments of a non-return valve according to a further aspect of the invention;  
         [0036]    [0036]FIGS. 11A to  11 C depict another embodiment of this aspect of a non-return valve incorporated in a quick connect coupling of a hydraulic line;  
         [0037]    [0037]FIG. 12 is an exploded sectional view of various components of the non-return valve of FIGS. 11A to  11 C; and  
         [0038]    [0038]FIG. 13 is a sectional representation of a membrane according to yet another aspect of the invention being permeable in one direction only. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0039]    As shown in FIGS.  2  to  5  there are various embodiments of a non-return valve shown generally as  10  constructed in accordance with one aspect of the invention. For ease of reference and in order to avoid repetition like components have been designated with the same reference numerals.  
         [0040]    In each example the non-return valve  10  comprises a valve body  12  and a valve membrane  14 . The valve body  12  is generally tubular and includes an elongate passageway  16  having an inlet and an outlet defined at its opposing ends  18  and  20 , respectively.  
         [0041]    The non-return valve  10  of these embodiments is moulded from a polymeric material, preferably an elastomer such as rubber or a nylon-based material. The selection of the appropriate material for the valve  10  will be obvious to one skilled in the art without trial and experimentation. The valve membrane  14  is in the form of a conical-shaped diaphragm formed integral with the tubular valve body  12 . The diaphragm  14  is configured as a generally conical-shaped element having a collapsible opening or aperture  22  located at or adjacent its apex. The conical diaphragm  14  is orientated with its apex in a downstream flow direction. The resiliently flexible material from which the diaphragm  14  is constructed ensures that the diaphragm  14  in a collapsed condition obstructs or closes the aperture  22  to prevent fluid flowing in a reverse direction toward the inlet  18 . On the other hand, pressurisation of fluid within the passageway  16  on the inlet side of the diaphragm  14  deflects the diaphragm  14  to expose the aperture  22 . Thus, with the aperture  22  exposed fluid is allowed to flow through the passageway  16  from the inlet  18  to the outlet  20  only.  
         [0042]    FIGS.  2  to  5  depict installation of variations on the non-return valve  10  in various applications. The non-return valve  10  of FIG. 2 is flared at its inlet  18  and is configured to seat within an internally and externally threaded nipple  24 . An externally threaded conduit  26  and an internally threaded conduit  28  then threadably engage the respective male/female threaded nipple  24  so as to form a mated union shown generally as  30 . The mated union  30  is designed so that sufficient compression is applied to the valve body  12  to seal it within the nipple  24 . It will be appreciated that the non-return valve  10  can be adapted to suit any standard and pre-existing plumbing components such as the threaded nipple  24  and conduits  26  and  28  described.  
         [0043]    [0043]FIG. 3 shows another non-return valve  10  which in this embodiment is suitable as a “slip on union” such as that used with adjacent lengths of irrigation tubing such as  32  and  34 . In this example the tubing  32  and  34  is expanded over respective ends of the tubular valve body  12 . As indicated in enlarged detail one or more barbs such as  36  may be included in the valve body  12  to both provide firm engagement with and enhance the seal between the tube  32  and  34  and the valve body  12 . Fitting of the polyethylene tube  32  or  34  to the valve  10  may involve heating of the tubing to improve its pliability. The tubing  32  or  34  will naturally cool under ambient conditions after it has been slipped over the valve body  12 .  
         [0044]    [0044]FIG. 4 shows another variant of the non-return valve  10  which may be substituted for the conventional pneumatic non-return valve  1 . In this embodiment the valve body  12  is provided with an external thread  38  for securing the valve  10  within a stem  40  The stem  40  is preferably that of the conventional pneumatic non-return valve  1 .  
         [0045]    [0045]FIG. 5 shows installation of the non-return valve  10  of FIG. 4 in a pneumatic tyre of a tubeless configuration. The valve stem  40  is located in a conventionally fabricated rubber casing  42  which includes an annular channel  44  in which a wheel rim is seated. Alternatively, the rubber casing may be formed integral with the non-return valve  10  in this example the height of the rubber casing  42  or valve body  12  is reduced so that it is stiffened for insertion into the wheel rim. Furthermore, an inner lip  46  of the casing or valve body  12  is reduced in sectional size and profile so as to assist in seating of the channel  44  about the rim.  
         [0046]    [0046]FIG. 6 illustrates one example of a non-return valve  50  according to another aspect of the invention. The non-return valve  50  is similar in construction to those described above with a tubular valve body  52  and a conical-shaped diaphragm  54 . The tubular body  52  includes a passageway  56  defining an inlet and outlet  58  and  60  either side of the diaphragm  54 . The diaphragm  54  is formed integral with the valve body  52  and fabricated or moulded from resiliently flexible polymeric materials.  
         [0047]    In this particular construction of the non-return valve  50  an annular flange  62  is provided at the inlet end of the valve body  52 . The valve body  52  fits about a filler tube  64  of a fuel tank and the flange  62  provides a seal against a panel  66  of a motor vehicle (not shown). In use, a filler nozzle  68  is retractably received within the valve  10  so as to deflect the diaphragm  54  to permit a flow of gasolene into the fuel tank via the nozzle  68 . Thus, the diaphragm  54  is resiliently deformed so as to expose a collapsible opening  70  through which the nozzle  68  passes. Importantly, the diaphragm  54  forms about the nozzle  68  to prevent the escape of gasoline vapours from the filler tube  64  or tank. When the nozzle is retracted from the valve  50  the valve membrane  54  returns to its collapsed condition wherein it obstructs or closes the collapsible opening  70 . Thus, in the collapsed condition fuel vapour is prevented from escaping the tank or flowing in a reversed direction toward the inlet  58 .  
         [0048]    FIGS.  7  to  9  schematically illustrate a moulding tool which is appropriate for forming a non-return valve such as  10  described above. The tool shown generally as  80  is designed for use in a conventional injection moulding machine.  
         [0049]    The tool  80  includes two (2) mutually engagable die sections  82  and  84 . Each of the die sections  82  and  84  includes a shaft and a collar  86 / 88  and  90 / 92 , respectively. The shaft  86  and collar  88  of one of the die sections  82  is machined together whereas the collar  92  is allowed to rotate on the shaft  90  of the other die section  84 . This allows for removal of the tool  80  from the external thread  38  of the non-return valve  10  of this example. The part cut-away view of FIG. 7 shows in some detail the internal geometry of the tool  80  which defines an internal cavity  94  for injection of the polymeric material. Importantly, a relatively thin projection  96  is connected to the shaft  86  and extends across the apex of the resultant valve  10 . This projection  96  thus forms or defines the collapsible opening or aperture  22  of the valve  10 .  
         [0050]    [0050]FIG. 8 illustrates the tool  80  of FIG. 7 in a retracted position with the die section  82  removed from the injected valve  10 . The collar  92  of the other die section  84  is then rotated so as to release the injected valve  10  from the tool  80 . As the injected polymer cools the membrane or diaphragm  14  is released from the shaft  90  of the other die section  84 . However, the shaft  90  of the other die section  84  may also include a plunger or other means to assist or aid in removal of the injected valve  10 . FIG. 8 also depicts injection and relief ports  98  and  100 , respectively, which provide a flow of polymer to the die cavity  90 . One of the die sections  82  or  84  may also include a dowel pin  102  for interengagement of the die sections  82  and  84 . The injector ports  98  provide a discriminate point for polymer to be injected uniformly throughout the cavity  9 C of the tool  80 . The relief ports  100  allow an even flow and distribution of injected polymer throughout the die cavity  90 .  
         [0051]    As shown in FIG. 10 there are three embodiments of a further aspect of a non-return valve  100  comprising a bank or series of non-return valves such as  120  and  140  of similar construction coupled to one another. The overall non-return valve  100  is thus of a “fail-safe” configuration. For ease of reference and in order to avoid repetition like components have been designated with the same reference numerals.  
         [0052]    In this particular construction of the fail-safe non-return valve  100  each of the series of non-return valves such as  120  and  140  includes a valve body such as  160  or  180  together with a corresponding valve membrane such as  200  or  220 . The valve bodies  160  or  180  are generally tubular and moulded together with the corresponding diaphragm  200  or  220  which is configured as a generally conical-shaped element. Importantly, the diaphragm  200  or  220  includes a collapsible aperture  240  or  260  formed at its apex. The conical diaphragm  200  or  220  is orientated with its apex in a downstream flow direction.  
         [0053]    In this example the collapsible diaphragms  200  and  220  are moulded from a polymeric material, preferably an elastomer such as rubber or a nylon-based material. The particular shape of the diaphragm  200  or  220  together with the resilient material from which it is constructed ensures that the diaphragm  200  or  220  in a collapsed condition obstructs or closes the aperture  240  or  260  to prevent fluid flowing in an upstream direction. On the other hand, with pressure imposed on an upstream side of either of the diaphragms  200  or  220  said diaphragm is deflected to expose the corresponding collapsible aperture  240  or  260 . Thus, with the collapsible apertures  240  or  260  exposed fluid is allowed to flow in a downstream direction through the fail-safe non-return valve  100 .  
         [0054]    [0054]FIG. 10 depicts two configurations of the fail-safe non-return valve  100  where either two non-return valves such as  120  and  140  are nested within one another or are of substantially the same configurations and merely abut one another. In the “nested” embodiment of the fail-safe non-return valve  100  the outer body  160  of the outer valve  120  is internally threaded and designed to engage the inner body  180  of the inner valve  140 . In the other embodiment, adjacent valve bodies  160  and  180  are aligned with one another and may together be housed or contained within a valve casing (not shown). In both cases the valve diaphragms such as  200  and  220  are oriented such that their respective collapsible apertures  240  and  260  are aligned and coaxial with one another. An internal bore of the valve bodies  160  and  180  together defines a fluid passageway  280  of the non-return valve  100  including a fluid inlet  300  and outlet  320 .  
         [0055]    [0055]FIGS. 11A to  11 C illustrate another aspect of a non-return valve according to the invention which in this embodiment is designed to be incorporated in a quick connect coupling shown generally as  500  of a hydraulic line or hose  520 . The hydraulic coupling  500  is designed to threadably engage a valve casing  540  in which another embodiment of a non-return valve  1000  is mounted. For ease of reference and in order to avoid repetition components of this non-return valve  1000  which are similar to the non-return valve  10  or  100  described above are designated with an additional “0”. For example, the diaphragms are designated as  200  and  2200 .  
         [0056]    In this application the valve diaphragms  200  and  220  are actuated not by fluid pressure but rather via a fluid nozzle which in this example is in the form of a fluid injector  560  which is connected to the hydraulic hose  520  via barbs  580  formed about a periphery of the injector  560 . FIGS. 11A to  11 C show the sequential steps involved in connecting the quick coupling  500  to the casing  540 . The injector coupling  500  is initially slid longitudinally along the injector  560  until it abuts an annular flange  600  formed about the injector  560 . The injector  560  is then pressed into engagement with the diaphragms  2000  and  2200  so as to expose their corresponding collapsible apertures  2400  and  2600 . The coupling  500  is progressively threaded onto the casing  540  so as to drive the injector  560  into engagement with the diaphragms  2000  and  2200 . Thus, in this example, hydraulic fluid or the like which is contained in the casing  540  and any associated plumbing is allowed to flow to the flexible hose  520  upon connection of the quick coupling  500 . The nozzle  560  thus serves as the means for actuating the valve  1000  of this particular aspect of the invention.  
         [0057]    [0057]FIG. 12 illustrates an exploded sectional view of the valve  1000  incorporated in the quick connect hydraulic coupling described. Each of the valve bodies  1200  and  1400  is designed to coaxially press-fit within the casing  540 . Each body  1200  and  1400  includes an annular recess  620  being shaped complementary to and designed to be engaged by a corresponding ridge  640  formed circumferentially within an inner surface of the casing  540 .  
         [0058]    [0058]FIG. 13 depicts one example of a membrane  1000 ′ of another aspect of the invention. The membrane  1000 ′ is permeable in one direction only and on a microscopic scale may be applied as a means of repairing a lung. The membrane  1000 ′ is multi-layered with a series of panels or blankets of collapsible diaphragms such as  2000 ′ being formed alongside one another. In this embodiment each of the diaphragms such as  2000 ′ includes a corresponding valve body  1600 ′ which is formed integral with an adjacent valve body of an adjacent diaphragm. However, it should be appreciated that the membrane  1000 ′ need not include this arrangement of valve bodies but rather may be limited to a panel or blanket of interconnected collapsible diaphragms. In any case the membrane  1000 ′ functions along the same lines as the non-return valve  10  or  100  described above. That is, pressure imposed on an upstream side of the membrane  1000 ′ deflects one or more of the diaphragms such as  2000 ′ to expose its corresponding aperture  2400 ′ to allow fluid to flow across the membrane  1000 ′. On the other hand, without a positive pressure imposed on the upstream side of the membrane  1000 ′, the diaphragms such as  2000 ′ are in a collapsed condition such that the collapsible apertures such as  2400 ′ are closed to prevent the flow of fluid in a reverse direction across the membrane  1000 ′.  
         [0059]    Now that several preferred embodiments of the various aspects of the present invention have been described in some detail it will be apparent to those skilled in the art that the non-return valve and permeable membrane have at least the following advantages:  
         [0060]    (i) the non-return valve is relatively simple in construction;  
         [0061]    (ii) the non-return valve is effective in operation relying on fluid pressure for opening, and valve membrane characteristics and design for closure; and  
         [0062]    (iii) the non-return valve is relatively inexpensive to manufacture.  
         [0063]    Those skilled in the art will appreciate that the invention described herein is susceptible to variations and modifications other than those specifically described. For example, injection moulding is merely one exemplary technique of forming the non-return valves. the diaphragm may be constructed of practically any resiliently flexible material which in a collapsed condition obstructs the collapsible aperture to prevent flow across the valve or membrane. The non-return valves may extend to applications other than those described above. For example, the fail-safe non-return valve may be connected across the skin of a ships hull and provide a means of quick evacuation where the human body can slip through the dual or multiple diaphragm valves.  
         [0064]    All such variations and modifications are to be considered within the scope of the present invention the nature of which is to be determined from the foregoing description.