CHECK VALVE FOR VENTING AN ENCLOSURE USING SURFACE TENSION BETWEEN DIFFERENT FLUIDS

Abstract: A valve (1) is described comprising a port (5) formed in a wall (6) associated with a first fluid-containing space. Port (5) communicates between an interior and an exterior of the container (2). It comprises a working space (7) adjacent the port (5), wherein the working space (7) diverges from the port (5) towards the interior. In use, a fluid interface (8), such as a meniscus, forms in the working space (7) which inhibits egress therethrough of a fluid stored within the container and which permits another fluid such as air to enter therethrough into the container. In other embodiments the port is provided in a closure of the container (particularly a nursing bottle) or in a wall of a conduit.

Description: CHECK VALVE FOR VENTING AN ENCLOSURE USING SURFACE TENSION BETWEEN DIFFERENT FLUIDS FIELD OF THE INVENTION THIS INVENTION relates to a pressure 5 equalization valve for venting a flow of fluid from a fluid containing space such as a container. In a particular, the valve allows the inflow of air to balance the outflow of liquid from a container without interrupting the fluid flow. 10 The invention finds particular application in venting the flow from a container of viscous liquids, such as oil or syrup, as well as low viscosity liquids, such as milk. BACKGROUND TO THE INVENTION 15 A wide variety of different venting arrangements are known for assisting the dispensing of fluid from a container. The simplest arrangement is to provide an air inlet port above the fluid level . For instance, a fuel container often has two ports on a top 20 portion. One port is for dispensing fuel and the other port allows air into the container to replace the dispensed fuel. The fuel must be poured carefully to ensure the fluid level does not get above the air inlet port. If this happens, fuel spills from both ports and 25 causes a hazard. In many applications, however, the above arrangement cannot be used. For example, there are situations in which it is desirable to completely invert a container when dispensing a fluid within to avoid 30 problems of directing a stream of the fluid into a narrow opening of a receiving vessel. If such inversion does not take place, the stream of fluid often strays outside the opening, either due to the size of the opening or to an unsteady hand. One example in which container inversion is required is the pouring of oil into a car engine. To minimize spillage, an oil bottle is usually completely inverted with the neck of the bottle inserted into the oil inlet. As the oil flows from the bottle, the pressure within the bottle drops due to inadequate venting, and flow slows until an air bubble bursts through the oil against the flow. Since conventional oil bottles can be inserted into the oil inlet of an engine, this is not much of a problem. However, larger oil containers, as for example 4 liter oil containers, are not provided with necks sufficiently long for insertion into the oil inlet. Therefore, complete inversion of such oil containers would typically result in spillage of the oil . This means that larger oil containers must be partially and carefully inverted to direct a stream of oil into the oil inlet. However, the inadequate venting problem associated with conventional oil containers remains, leading to an uneven flow of oil and even surges of flow that generally cause splashing and spillage of the oil. Moreover, larger containers such as those used for transfer of cooking or machine oils, cleaning fluids, pesticides, fertilizers, and even biological substances suffer another disadvantage. When fluid is being poured from such containers, the turbulence created by surges of flow of fluid can shift considerably the weight of the container making it difficult to hold steady and/or to dispense a particular volume of fluid. Disadvantages associated with container inversion also apply to nursing or baby's bottles. The infant sucks the liquid from a baby's bottle thereby generating a vacuum in the bottle. Eventually the vacuum generated in the bottle prevents continued flow of the liquid. At this point a bubble bursts through the liquid to equalize the pressure and flow continues. Sometimes, the bubbles are entrained by the liquid flow and ingested by the baby. This can contribute to colic. A number of attempts have been made to produce a valve that regulates flow from a baby's bottle. One such attempt is described in United States patent number US 5,399,971 in the name of Rόhrig. This patent discloses a feeding bottle having a microporous air inlet in the base. The micropores are sufficiently small to prevent liquid leaking from the bottle but sufficiently numerous to provide adequate venting of the bottle. Production of a container incorporating a microporous base is difficult and therefore expensive. In many applications the additional production cost renders the solution nonviable. Another option is described in United States patent number US 5,284,261 to Zambuto. Zambuto describes an insert placed between the bottle and the teat that provides a path to allow air to enter the bottle but to prevent liquid exiting the bottle. Operation of the Zambuto arrangement relies on holes in the insert being small enough that liquid will not flow through. The problem of venting a baby's bottle has not yet been satisfactorily addressed. A very recent United States patent (US 5,699,921) in the name of Rodriguez seeks to address the problem of letting air into a baby' s bottle by providing a one way valve in the base of the bottle. However, the Rodriguez arrangement is unduly complex which would substantially inflate production costs . As mentioned above, the venting problem is not restricted to baby's bottles. United States patent number US 4,753,546, to Witz et al , describes a pressure balanced stylographic pen. Witz et al describe a vent channel of varying cross-sectional area that exactly balances the capillary pressure on the meniscus of a column of ink against the gravitational pressures forcing the ink from the pen. Although not directly related to the venting problems described above, the Witz patent includes a useful analysis of the LaPlace equation as it relates to the net pressure at a curved air/liquid interface. OBJECT OF THE INVENTION It is an object of the present invention to substantially overcome one or more of the problems identified in the known prior art. Further objects will be evident from the following description. DISCLOSURE OF THE INVENTION According to one aspect of the invention, there is provided a valve for inhibiting egress therethrough of a first fluid in a first fluid-containing space and for permitting entry therethrough of a second fluid in a second fluid-containing space, said valve comprising: a port formed in a wall separating the first fluid-containing space and the second fluid-containing space, said port communicating between the first fluid containing space and the second fluid containing space; a working space adjacent the port, said working space diverging from the port towards the first fluid- containing space; and a fluid interface forming in said working space, in use. Preferably, the working space is frusto- conical . In use, the second fluid from the second fluid- containing space moves across the interface to the first fluid-containing space to equalize a pressure difference between the first fluid-containing space and the second fluid-containing space. Typically, the first fluid in the first fluid-containing space is a liquid and the second fluid in the second fluid-containing space is air. In this instance, it will be appreciated that the fluid interface forming in the working space is a meniscus. Preferably, the first fluid-containing space has an outlet associated therewith through which the first fluid is dispensed thereby causing a reduction in pressure within the first fluid-containing space. Suitably, the first fluid-containing space may define the interior of a container. In such a case, the wall separating the first fluid-containing space and the second fluid-containing space may define a wall associated with the container. For example, in this instance, the wall may be a wall of the container, or a wall of a discharge member associated with the container. Alternatively, the first fluid-containing space may define the interior of a conduit member for conveying the first fluid from a fluid source. In this case, the wall may define a wall of the conduit member. The conduit member may comprise any suitable tubing, hose, pipe, vessel and the like. Alternatively, the conduit member may comprise a hollow connecting piece for connecting two or more conduits in fluid communication therebetwee . In another aspect, the invention resides in a container having at least one valve comprising: a port formed in a wall of the container and communicating between an interior of the container and an exterior of the container; a working space adjacent the port, said working space diverging from the port towards the interior of the container; and a fluid interface forming in said working space, in use. The at least one valve may project outwardly of the container. In such a case, the at least one valve may extend from a recessed portion of the container wall such that the port of the valve is coextensive with, or inwardly of, an exterior surface of the container wall adjacent the recessed portion. The at least one valve may be disposed at any suitable location in the container. In preference, the at least one valve is located in a top portion of the container and more preferably, adjacent a fluid outlet of the container. Suitably, the at least one valve is sealable by a sealing means. For example, the sealing means may comprise a cover or collar adapted to engage the container and to seal the at least one valve. The container may be used for any suitable application which requires fluid to be dispensed therefrom. For example, the container may be a nursing or baby's bottle. Alternatively, the container may be an oil bottle or container. In yet another aspect, the invention provides a discharge member for discharging a fluid from a container, said discharge member including at least one valve comprising: a port formed in a wall of the discharge member and communicating, in use, between an interior of the container and an exterior of the container; a working space adjacent the port, said working space diverging, in use, from the port towards the interior of the container; and a fluid interface forming in said working space, in use. Preferably, a fluid outlet of the discharge member is adjacent said wall. Suitably, a plurality of said valves are formed in said wall and are concentrically disposed adjacent the periphery of the fluid outlet. In preference, the discharge member comprises a nozzle, spout, mouthpiece and the like. Alternatively, the discharge member may comprise an aperture through which a nursing teat is projectable. In a further aspect, the invention provides a conduit member for conveying a fluid from a fluid source, said conduit member including at least one valve comprising : a port formed in a wall of the conduit member and communicating between an interior of the conduit member and an exterior of the conduit member; a working space adj acent the port , said working space diverging from the port towards the interior of the conduit member; and a fluid interface forming in said working space, in use. In yet another aspect, the invention resides in a method of venting flow of a first fluid from a first fluid-containing space, said method including the step of: forming a fluid interface in or adjacent a vent associated with the first fluid-containing space such that the fluid interface inhibits egress of the first fluid from the vent and permits entry of a second fluid from a second fluid-containing space exterior of the first fluid-containing space. In a still further aspect of the invention, there is provided a method of venting flow of a liquid into a container having a liquid inlet port and having at least one valve comprising a port formed in a wall associated with the container and communicating between an interior of the container and an exterior of the container, a working space adjacent the port, said working space diverging from the port towards the interior of the container, and a fluid interface forming in said working space, in use, said method including the step of: dispensing the liquid into the container through the liquid inlet port to cause egress of a gas within the container through the at least one valve. Throughout this specification and the appendant claims, unless the context requires otherwise, the words "comprise" , "comprises" and "comprising" will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers. BRIEF DESCRIPTION OF THE DRAWINGS To assist in understanding the invention preferred embodiments will now be described with reference to the following figures in which : FIG 1 is a perspective view of a first embodiment of a valve employed on a container; FIG 2 is a cross-sectional view of the embodiment of FIG 1 ; FIG 3 is an enlarged view of a portion of FIG 2; FIG 4 is a cross-sectional view of another embodiment of the invention showing the method of operation; FIG 5 is a cross-sectional view of yet another embodiment of the invention applied to a baby's bottle; FIG 6 is a cross-sectional view of a further embodiment of the invention applied to an oil container; FIG 7 is a top view of the embodiment of FIG 6; FIG 8 is an enlarged view of a portion of the last mentioned embodiment; FIG 9 is a cross-sectional view of yet a further embodiment of the invention applied to a tube; and FIG 10 is a cross-sectional view of a still further embodiment of the invention applied to a hollow connecting a pair of tubes. DETAILED DESCRIPTION In the drawings, like reference numerals refer to like parts. In FIG'S 1 - 3 there is shown a valve 1 formed in the wall of a container 2 holding a liquid 3. The container 2 has an outlet 4 from which fluid 3 flows when the container 2 is inverted (as shown in FIG 2) or partially inverted. The valve 1 comprises a port 5 communicating between the interior of the container and the exterior of the container. The wall 6 of the container 2 in the vicinity of the port 5 slopes away from the port so as to form a working space 7 in which an air pocket is formed. The working space 7 has a smaller cross-sectional area near the port 5 than at the interior of the container 2. The working space is shown as frusto-conical although other shapes, such as pyramidal, will be suitable. The port may also take different shapes such as circular, square or hexagonal. In the present embodiment, the valve 1 projects outwardly of the container 2 extending from a recessed portion 100 such that the port 5 is substantially coextensive with an exterior surface 101 adjacent the recessed portion 100. A meniscus 8 forms at the interface between the liquid 3 in the container 2 and the gas (normally air) in the working space 7. The meniscus prevents the liquid 3 from leaking from the container 2 through port 5. The position of the meniscus 8 in the working space 7 will be determined by the pressure difference between the interior and the exterior of the container. As fluid 3 flows from the container 2 the pressure within the container drops . In the absence of the valve 1 the flow would cease or be slowed until a bubble of air bursts through outlet 4 against the flow. However, as shown in FIG's 2 - 3, the valve allows air to enter the container through the port thereby equalizing the pressure difference and allowing flow of fluid through outlet 4 to continue without disruption. The process of pressure equalization can best be described by reference to a second embodiment of the valve shown in FIG 4. In FIG 4, the valve 9 has been simplified to a port 10 in wall 11 of a container (not shown) opening to a working space 12 formed in the wall 11. The liquid on the space side of the wall has been omitted for clarity. Due to surface tension, a meniscus 13 forms in the working space 12 at a position determined by the properties of the fluid in the container, the gas outside the container, the wall material and ambient pressure, as shown in FIG 4 (a) . The analysis provided in US 4,753,546 is useful for calculating the position of the meniscus, if desired. As fluid flows from the container, the pressure within the container drops and the position of the meniscus moves, as depicted in FIG 4(b) . Air fills a larger portion of the space 12. At some point, a bubble 14 forms and breaks away from the valve 9, as shown in FIG 4(c). The meniscus 13 reforms and the process is repeated as long as fluid flows from the container and the fluid level remains above the level of the valve 9. The bubbles of air from the exterior of the container replace the fluid flowing from the container so flow continues without disruption, as indicated in FIG 2. The inventor has found that the valve may usefully be employed on a baby' s bottle as depicted in FIG 5. FIG 5 shows a bottle 20 to which a teat 21 is attached by nut 22. The teat is protected by cap 23 which clips to the bottle, such as in the manner shown. In conventional manner, the bottle 20 is open at one end to allow flow of liquid from the bottle and out the teat 21. A valve 24 is formed in the neck 25 of the bottle 20. When the bottle 20 is inverted, liquid in the bottle covers the valve and a fluid interface is formed, as described above. It will also be appreciated that when cap 23 is clipped onto the bottle as shown, it seals the valve 24 against entry of air exterior of the bottle 20. Another application found by the inventor is shown in FIG 6. In FIG 6 there is shown a container 30 holding a viscous fluid 31, such as oil. Part of one wall of the container is formed by a cap 32 screwed onto the container 30. The cap has an outlet 33 for dispensing fluid 31 by inverting the container 30. Oil is typically dispensed by inverting the container so that an outlet 33 is inserted into the oil reservoir of a vehicle (not shown) . A plurality of valves, such as 34, are formed in the cap 32. It is convenient to form the valves concentrically around the outlet, as shown in FIG 7, although not essential to do so. Each valve has the configuration shown in FIG 8. A port 35 communicates between the exterior and interior of the container. A meniscus 36 forms in the working space 37 adjacent the port 35. The working space 37 is formed by the wall 38 of the cap 32 diverging away from the port 35. As fluid 31 flows from the outlet 33, a stream of bubbles, such as 39, carry air into the container to replace the fluid. In the absence of the valves, the fluid flow slows until a bubble bursts through the fluid against the flow. The embodiment shown in FIG's 6-8 has the advantage of having the valves as near as possible to the outlet. This ensures that the fluid covers the valves for as long as possible . The inventor has found that the valves self-regulate the flow of fluid from the container so there is advantage in positioning the valves close to the outlet . Once the fluid level gets below the position of the valve, air is able to flow directly into container and the rate of flow of fluid from the container increases . The inventor has also found that the valve may be employed advantageously in a conduit such as a tubing, as for example shown in FIG 9 for conveying a fluid. In FIG 9, a plastics tubing 200 is shown conveying a fluid 201A from a container 201 in the direction of the arrow to a fluid destination (not shown) . A valve 202 is formed in the wall of tubing 200, comprising a port 203 opening to a working space 204 in which a meniscus 205 forms. The inventor has found that application of the valve to conduits such as tubing and the like assists venting of fluid flow from a suitable fluid source such as a container. In this embodiment, when fluid flows from the container 201 along tubing 200, a decrease in pressure will result within the tubing 200 relative to the tubing exterior. This will cause an inflow of air into the tubing and consequent formation of bubbles 206. The bubbles so formed will then travel along the tubing against the flow of fluid 201A to replace the fluid flowing from the container 201 so that flow continues without disruption. Those of ordinary skill in the art will appreciate that the diameter of tubing will be selected to be substantially greater than the diameter of the bubbles 206 entering the tubing from valve 202. This is important so that the bubbles entering the tubing do not interfere with fluid flow in the opposite direction. The valve does not have to be formed in the wall of the tubing. In this regard, the valve may be applied to a hollow tubing connector as for example shown in FIG 10. The tubing connector shown generally at 300 fluidly connects two pieces of tubing 301, 302 which are fluidly connected to a fluid source (not shown) for conveying a fluid 303 in the direction of the arrow to a selected destination (not shown) . Connector 300 has a substantially cylindrical body 304 and a pair of tapered ends 305, 306 to which are sealingly fitted ends 301A and 302A of tubes 301, 302. A pair of valves 307, 308 are formed in the wall of body 304. Each valve comprises a port 309 communicating between the exterior and interior of the connector 300. In use, a meniscus 310 forms in a working space 311 adjacent the port 309 as described in the aforementioned embodiments. The present embodiment provides a relatively facile means by which fluid flow from a fluid source can be adequately vented. In this regard, a connector, as for example shown in FIG 10, can be fitted with relative ease to an existing conduit by cutting the conduit at a desired location to form two free ends and subsequently connecting the connector therebetween. The valve is useful for venting gravity assisted flows, such as the oil container embodiment, or vacuum assisted flows, such as the baby bottle example. The valve is also useful when filling a container. When a container, for example the container of FIG 6, is upright the valve will be above the fuel level and therefore a fluid interface will not form. Liquid may then be poured in the outlet with air in the container being expelled through the valve. The valve may also be employed in conduits, conduit connectors and the like for venting fluid flow from a fluid source such as a container. The inventor has also found that the rate of fluid flow from a fluid source may be regulated by the application of different numbers of valves. For example, a single valve may be provided for applications in which the rate of fluid flow from a fluid source is desired or required to be relatively low. Alternatively, a plurality of valves may provided for applications in which the rate of fluid flow is desired or required to be high. As will be appreciated, the valve is particularly simple to manufacture but very effective. It substantially overcomes the problems of venting the flow of fluid from a container, for example, and is self regulating. The valve can be formed in virtually any container, discharge member or conduit member. Throughout the specification the aim has been to describe the preferred embodiments of the invention without limiting the invention to any one embodiment or specific collection of features. It will therefore be appreciated by those of skill in the art that, in light of the instant disclosure, various modifications and changes can be made in the particular embodiments exemplified without departing from the scope of the invention. All such modifications and changes are intended to be included within the scope of the appended claims .

Claims: CLAIMS 1. A valve for inhibiting egress therethrough of a first fluid in a first fluid-containing space and for permitting entry therethrough of a second fluid in a second fluid-containing space, said valve comprising: a port formed in a wall separating the first fluid-containing space and the second fluid-containing space, said port communicating between the first fluid containing space and the second fluid containing space; a working space adjacent the port, said working space diverging from the port towards the first fluid- containing space; and a fluid interface forming in said working space, in use. 2. The valve of claim 1, wherein the working space is frusto-conical . 3. The valve of claim 1, wherein the second fluid from the second fluid-containing space moves across the interface to the first fluid-containing space to equalize a pressure difference between the first fluid-containing space and the second fluid-containing space, in use. 4. The valve of claim 1, wherein the first fluid- containing space has an outlet associated therewith through which the first fluid is dispensed thereby causing a reduction in pressure within the first fluid- containing space. 5. The valve of claim 1, wherein said wall defines a wall associated with a container. 6. The valve of claim 5, wherein said wall defines a wall of the container. 7. The valve of claim 5, wherein said wall defines a wall of a discharge member associated with the container . 8. The valve of claim 1, wherein said wall defines a wall of a conduit member. 9. The valve of claim 8, wherein the conduit member is selected from the group consisting of a hose, pipe, tubing, and vessel. 10. The valve of claim 8 wherein the conduit member comprises a hollow connecting piece for connecting two or more conduits in fluid communication therebetween. 11. A container having at least one valve comprising : a port formed in a wall of the container and communicating between an interior of the container and an exterior of the container; a working space adj acent the port , said working space diverging from the port towards the interior of the container; and a fluid interface forming in said working space, in use. 12. The container of claim 11, wherein the at least one valve projects outwardly of the container. 13. The container of claim 12, wherein the at least one valve extends from a recessed portion of the container wall such that the port of the valve is • coextensive with, or inwardly of, an exterior surface of the container wall adjacent the recessed portion. 14. The container of claim 11, wherein the at least one valve is located in a top portion of the container. 15. The container of claim 11, wherein the at least one valve is located adjacent a fluid outlet associated with said container. 16. The container of claim 11, wherein the at least one valve is sealable by a sealing means. 17. The container of claim 16, wherein the sealing means comprises a cover or collar adapted to engage the container and to seal the at least one valve. 18. The container of claim 11, wherein the container is a nursing or baby's bottle. 19. The container of claim 11, wherein the container is an oil bottle or an oil container. 20. A discharge member for discharging a fluid from a container, said discharge member including at least one valve comprising: a port formed in a wall of the discharge member and communicating, in use, between an interior of the container and an exterior of the container; a working space adjacent the port, said working space diverging, in use, from the port towards the interior of the container; and a fluid interface forming in said working space, in use. 21. The discharge member of claim 20, wherein a fluid outlet of the discharge member is adjacent said wall . 22. The discharge member of claim 21, wherein a plurality of said valves are formed in said wall and are concentrically disposed adjacent the periphery of the fluid outlet . 23. The discharge member of claim 20, wherein the fluid outlet comprises a nozzle or spout. 24. The discharge member of claim 20, wherein the fluid outlet comprises an aperture through which a nursing teat is projectable. 25. A conduit member for conveying a fluid from a fluid source, said conduit member including at least one valve comprising: a port formed in a wall of the conduit member and communicating between an interior of the conduit member and an exterior of the conduit member; a working space adj acent the port , said working space diverging from the port towards the interior of the conduit member; and a fluid interface forming in said working space, in use. 26. The conduit member of claim 25, wherein the conduit member is selected from the group consisting of a hose, pipe, tubing, and vessel. 27. The conduit member of claim 25, wherein the conduit member comprises a hollow connecting piece for connecting two or more conduits in fluid communication therebetween. 28. A method of venting flow of a first fluid from a first fluid-containing space, said method including the step of : forming a fluid interface in or adjacent a vent associated with the first fluid-containing space such that the fluid interface inhibits egress of the first fluid from the vent and permits entry of a second fluid from a second fluid-containing space exterior of the first fluid-containing space. 29. A method of venting flow of a liquid into a container having a liquid inlet port and having at least one valve according to claim 1 associated therewith, said method including the step of : dispensing the liquid into the container through the liquid inlet port to cause egress of a gas within the container through the at least one valve.

Inventors: KIEHNE MARK WILLIAM, KIEHNE, MARK, WILLIAM
Applicants: JET FLO PTY LTD, KIEHNE MARK WILLIAM, JET FLO PTY. LTD., KIEHNE, MARK, WILLIAM
Application year: 1998
Main classification: F16K15
IPC codes: A01K9, A61J9, B65D51