GB2092679A - Liquid dispensing apparatus - Google Patents

Abstract

Apparatus for use in dispensing a liquid such as beer from a container, comprises means (19) such as a tube (19b), or a squeeze bulb air pump, for introducing a gas into a vessel (11) through a uni-directional valve (19) for retaining the gas in the vessel, and a flexible membrane (16) which may be in the form of a resilient sac adapted to maintain the introduced gas out of contact with a liquid in the vessel, whereby to allow pressurisation of the vessel without absorption of the gas by the liquid. <IMAGE>

Description

SPECIFICATION Liquid dispensing apparatus The present invention relates to liquid dispensing apparatus for use in dispensing liquid from a vessel. Although the apparatus of the present invention is applicable to the dispensing of any liquid, it is particularly adapted for the dispensing of liquid containing dissolved gases, such as beer.

Commercially, much beer is distributed in barrels and the beer is dispensed from the barrels at that point of sale by pressurising the interior of the barrel with carbon dioxide. Before being dispensed the beer itself is devoid of any natural dissolved gases so that the "condition", that is the dissolved gases in the beer, is introduced entirely artificially by this injection of carbon dioxide.

On a smaller scale, and by contrast with the commercial process, home-brewed beer generally has a natural condition, and this is preserved by storing the beer in small quantities such as in bottles. However, the sterilisation of the bottles and bottling of the beer is a tedious and timeconsuming component of the home-brewing process, and produces only bottled beer; the socalled "draught" beers which are dispensed from bulk in public houses cannot be readily produced.

The main reason for this is the rate of consumption of home-brewed beer, which is very much lower than the rate of consumption of beer in public houses. For example, a container holding 10 or 1 5 gallons of beer would last the average household several weeks, and in this time the airspace above the beer, which is continually increasing in size as the beer is drawn off, allows the gases generated in the beer by the final fermentation to be given off into the air so that the beer becomes flat and insipid. In public houses the beer is consumed before this effect can take place so its does not present a serious problem. The introduction of air from the atmosphere also allows contaminants to enter the vessel, and this can sometimes lead to a rapid degeneration in the quality of the beer.

One prior art attempt to overcome this problem and to allow home brewers to produce "draught" beers has been the provision of small capsules of carbon dioxide which can be injected into the air space above the liquid in the vessel to pressurise the container. This has a number of disadvantages, and although it works in the short time to maintain the pressure within the vessel and allow dispensing, the beer gradually absorbs the carbon dioxide from the air-space so that the vapour pressure in the air-space falls and, moreover, the beer acquires an excessive content of carbon dioxide losing its natural "condition".

This is unacceptable to the majority of home brewers, and unsatisfactory in practice due to the continual requirement to re-inject carbon dioxide at regular intervals. The present invention seeks, therefore, to provide apparatus for dispensing iiquids from a vessel, by means of which the liquid can be dispensed containing the natural gases dissolved therein, without losing these gases and becoming flat as would occur if the liquid were merely drawn off the vessel over a period of several weeks, whilst at the same time avoiding the unacceptable increase in dissolved gas and "fizziness" due to the presence of artificially injected carbon dioxide.

According to one aspect of the present invention apparatus for use in dispensing a liquid from a vessel comprises means for introducing a gas into the vessel through a unidirectional valve for retaining gas in the vessel, and a flexible membranes adapted to maintain the introduced gas out of contact with any liquid in the vessel, whereby pressurisation of the vessel can take place without absorption of the gas by the liquid.

The membrane may take any suitable form, and may conveniently be introduced through an opening in the vessel, through which opening the liquid contained in the vessel is itself introduced.

In such a case the membrane must be readily removable from the vessel to allow subsequent cleaning of both the membrane and the vessel.

Alternatively, of course, the vessel may be constructed with a resilient membrane spanning a part thereof and separating the vessel into two chambers one for liquids and the other for gas, the resilience of the member being sufficient to allow it to accommodate wide variations in the relative volumes of the two chambers.

In another aspect of the present invention there is provided apparatus for use in dispensing a liquid from a vessel, which permits a gas to be introduced under pressure into the vessel but which maintains the gas out of physical contact with the liquid whereby absorption of the gas by the liquid is prevented.

In a further aspect the present invention provides apparatus for use in dispensing a liquid from a vessel, comprising a membrane adapted to be fitted into the vessel, and a valve for allowing gas to be introduced into the vessel to pressurise the interior thereof; the membrane being so formed in relation to the valve that it isolates liquid in the vessel from contact with the gas introduced through the valve whilst allowing pressure increases due to the pressure of the gas to be transmitted to the liquid.

In a preferred embodiment of the invention the membrane is formed as a closed container for containing gas introduced into the vessel. The membrane need not be resilient if it is sufficiently large to line at least that part of the interior space of the vessel to one side of its attachment to the vessel. For example a substantially flat membrane may be secured around a mid line of the vessel.

(which may suitably be made separable to permit fitting and removal) and alternatively if the membrane is in the form of a sac with a narrow neck it may conform substantially to the shape of the interior of the container. Thus, providing the membrane is flexible it will be able to fold up to accommodate variations in size so that when the vessel is almost completely filled with liquid the membrane can be accommodated in the small air space due to its folds.

Preferably the valve is formed as part of a stopper for an opening in the vessel. The stopper may have the membrane permanently attached thereto, or it may be adapted for attachment to the stopper. Alternatively the membrane may be provided with a suitably shaped neck to be trapped between the neck of the vessel and the stopper thereby forming a suitably gas tight seal, and in all of these cases the membrane must be formed as a closed container or sac for retaining the gas injected into it during use.

The gas used may be of any type since it will not come into contact with the liquid in the vessel, and can therefore not contaminate it. In particular, it is no longer necessary to use carbon dioxide as in prior art apparatus, and a simple compression pump such as a squeeze bulb for air can be included in the apparatus, either separate from or included as part of the stopper.

In another embodiment of the invention the valve is formed not only as part of the stopper for an opening in the vessel, but also as a combined uni-directional and pressure-relief valve calibrated to relieve pressure within the vessel when it exceeds a predetermined threshold value. The purpose of this arrangement is in part as a safety feature against the possibility of excess pressure being generated by fermentation, and partly as a simple way of achieving a predetermined optimum pressure within the container. If the valve allows gas into the container until a certain threshold value is reached, following which it allows any further gas to escape to the atmosphere, this will automatically allow pressurisation to this optimum valve without needing any complicated calibration or measuring instruments.In addition, since it will be certain that the container will never have to withstand more than the threshold value the container can be made as economically as possible as opposed to the previous situation where containers had to be strong enough to withstand possible excess pressures generated by the fermentation if this was not skilfully handled.

A very simple valve could comprise a springloaded ball closing and opening in a resiliently located valve obturator. The ball allows gas to pass in one direction from a pressure source to the interior of the vessel whilst an increase in the pressure of the gas within the vessel would cause the valve obturator to move from its valve seat against the resilient bias thereof thus allowing escape of gas from the interior of the vessel untilthe pressure within the interior of the vessel is balanced with the force exerted by the resilient biasing on the obturator. If required means can be provided for adjusting this resilient biasing force so that the calibrated pressure at which the valve operates can be varied over the range of operating pressures.

In a practical embodiment the means for introducing gas into the container include a gas duct leading to the interior of the container, a unidirectional valve in the duct allowing gas to flow towards the interior of the container, and a pressure relief valve in gas communication with the interior of the membrane allowing gas within the container to exhaust to the atmosphere when the pressure in the interior of the container exceeds a predetermined value. Conveniently the means for introducing gas into the container may also include a length of tubing terminating in a mouthpiece and incorporating, or being associated with, a uni-directional valve allowing gas to be introduced into the vessel on the side of the membrane remote from the liquid.

The pressure relief valve may be of any one of a number of different types. It may, for example be a conventional flat membrane valve terminating one end of the branch tube, although in a preferred embodiment of the invention the pressure relief valve is in the form of a plurality of radial passages in a duct, the passages being closed by a resilient valve member surrounding the duct. This resilient valve member is preferably an endiess band, and may in the preferred embodiment be constituted by a conventional rubber band.

The connection between the membrane and the valve assembly is preferably made by introducing a circumferentially ridged spigot into the neck of the membrane. The circumferential ridges of this spigot may be formed, for example, by an external screw thread on the spigot, although to stop thread creeping, the threads may be removed from the end of the tube and a flat surface with an annular groove for the rim of the membrane to fit into be provided.

Various embodiments of the present invention will now be more particularly described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a schematic sectional view of a vessel equipped with means for assisting the dispensing of liquids formed as an embodiment of the present invention; Figure 2 is an axial section on an enlarged scale of part of Figure 1; Figure 3 is a cross sectional view of a second embodiment of the present invention; and Figure 4 is a cross sectional view on an enlarged scale of a part of a third embodiment of the invention.

Referring first to Figures 1 and 2 of the drawings there is shown a vessel 11 in the form of a barrel which may be a plastics or wooden barrel, or indeed may be made of any material suitable to withstand the pressures involved. Near the bottom of the barrel is a tap 1 2 for drawing off liquid, this tap being spaced a little way from the bottom 13 of the barrel to allow the deposition of sediment without this being drawn off with the liquid. In the air-space 14 above the level of liquid 1 5 in the barrel 11 there is located a closed flexible resilient membrane which in its natural state is approximately the same shape as, but slightly smaller than the interior volume of the barrel 11.

The membrane 1 6 has a neck 1 7 attached to a stopper 1 8 which incorporates a valve generally indicated 1 9 by means of which gas can be introduced into the interior of the membrane within the air-space 14.

Details of the valve are shown on an enlarged scale in Figure 2. Referring now to Figure 2, the valve 1 9 is shown as being formed as a common assembly with the cap 1 8 which comprises a disc like base member 20 having an annular skirt 21 internally threaded to enable the cap to be screwed onto a correspondingly threaded part of the neck 1 7 of the barrel 11. Attached to the disc portion 20 of the cap 1 8 is a cylindrical body 22 having an inwardly directed radial flange 23 which retains in position a disc-like valve obturator 24, a resilient annular sealing washer 25 being interposed between the flange 23 and the obturator 24.

The obturator 24 carries a cage 26 in the form of a U-shape frame the arms 26a of which are attached at their free ends to the obturator and the transverse linking portion of which retains a spring 27 which acts between the cage 26 and the obturator 24 to retain a ball 28 in the conically flared mouth 29 of an axial passage 30 passing through the obturator 24.

Within the body 22 there is housed a spring 31 which reacts between the disc-like portion 20 of the cap 1 8 and the obturator 24 to press this against the annular sealing washer 25. The axial passage 30 in the obturator 24 receives one end of a tubular element 32 the other end of which projects from the disc portion 20 of the cap 18 and is externally threaded to receive a connector from a pump. The disc portion 20 of the cap 1 8 has a plurality of apertures 33 formed therein (only one of which is shown in Figure 2) allowing the space within the body 22 between the disc portion 20 and the obturator 24 to communicate with the atmosphere.

In operation of the apparatus described above the liquid to be stored in the vessel is introduced through the opening in the top and then the membrane 1 6 is fed through to occupy the air space above the liquid surface. The neck of the membrane 1 6 is shaped to fit closely within the neck 1 7 and has radially outwardly directed flange which overlies the end face of the cylindrical form of the neck 1 7 so that when the cap 1 8 is screwed thereon this radially outwardly directed flange is trapped between the end face of the neck 1 7 and the annular portion of the disc 20 of the cap 18 which lies between the skirt portion 21 and the cylindrical body portion 22 to form a seal therewith.

The liquid 1 5, if it is beer, will have been introduced into the vessel 11 with a certain amount of sugars still to be converted by fermentation into carbon dioxide and this is allowed to take place over the required period of weeks. When it is required to dispense the beer from the vessel a pump is attached to the spigot portion of the tube 32 and compressed gas, for example air, introduced through this tube into the passage 30 in the obturator 24 displacing the ball 28 from the conical seat 29 and compressing the spring 27 allowing the gas to enter the closed membrane 1 6. The membrane expands to occupy the whole of the air-space within the container and at the same time exerts a pressure on the liquid 1 5 within the vessel.When the required pressure has been reached the valve shutter 24 is displaced against the action of the springs 31 which is calibrated for this purpose, and this opens the interior chamber 34 between the valve shutter 24 and the disc portion 20 to the interior of the membrane since the valve shutter 24 is a loose fit within the cylindrical body 22. It should also be noted that the valve shutter 24 is a sliding fit on the tubular member 32 and is sealed to it by means of the small inserted sealing ring 35 lodged in an annular groove in the passage 30.With displacement of the valve shutter 24 from the sealing ring 25 the interior of the membrane 1 6 can communicate with the chamber 34 and from there through the passages 33 with the atmosphere so that any pressure differential between the interior of the membrane 1 6 and the atmosphere is allowed to equalise. before such equalisation takes place, however, the pressure in the interior of the membrane 1 6 will fall to a level lower than that at which the spring 31 urges the valve shutter 24 against the sealing ring 25 to close off communication between the interior of the membranes 1 6 and the atmosphere.This predetermined pressure is thus always maintained within the vessel 11 and can readily be renewed, after some of the liquid 1 5 has been withdrawn through the tap 12, simply by applying pressure to the valve 19 again until an escape is detected through the passage 33, at which point the pressure within the membrane 16 will have returned to the present value.

In the embodiment of Figure 3 those components which are the same as or fulfill the same or a similar function to corresponding components of the embodiment of Figures 1 and 2 have been identified with the same reference numerals. In Figure 2 there is shown a container 11 having a tap 12 spaced from the bottom leaving a space for the collection of sediment 1 3 from liquid 1 5 in the container 11. Above the liquid 1 5 is an air-space 14 which is of variable dimensions depending on how much liquid 1 5 is drawn through the tap 12. The upper end of the container 11 is closed by a cap 18 having a valve assembly secured thereto.This valve assembly comprises a generally vertical duct 1 9 passing through the cap 1 8 and clamped in position by two clamping rings 1 8a, 1 8b above and one below the cap 18.

The lower end of the duct 19 is threaded and over this threaded lower end there is fitted the neck of the resilient membrane 1 6 which is in the form of a closed bag or balloon. The duct 19 has two branches 1 9a, 1 9b, at right angles to one another; the horizontal branch 1 9b is fitted with a mouthpiece 38 at its free end, which mouthpiece incorporates a uni-directional valve.

The vertical duct branch 1 9a terminates in a pressure relief valve 37 fitted onto the end thereof.

The pressure relief valve 37 is of a flat diaphragm type of conventional construction which can be adjusted to release the pressure at a selected value within a given range determined by the dimensions of the components of the valve. Since the pressure relief valve 37 is a conventional commercially available structure its details will not be described herein.

In operation of the device the container 11 is partly filled with liquid 1 5 and then the cap 18 is fitted into position, the membrane 16 being inserted through the neck of the container 11 into the air-space 14. The membrane 16 is then partly inflated by blowing through the mouthpiece 38 with the cap 1 8 located in position but not tightened down so that air within the air-space 14 can escape between the neck of the vessel and the cap 1 8. Once all the air from the air-space 14 has been expelled, that is with the membrane 1 6 in its inflated position pressed again the inner sides of the vessel 11 and the surface of the liquid 15, the cap 18 can be tightened down to form a seal.Pressurisation of the contents of the vessel can take place by again blowing through the mouthpiece 38 until the preset pressure determined by the adjustment of the pressure relief valve 37 has been reached, at which stage further blowing into the mouthpiece 38 will merely cause operation of the pressure relief valve 37 so that no greater increase in pressure can be achieved.

If, as is envisaged, the liquid in the container 11 is beer, the secondary fermentation of which will now take place as the final stage in the production of the beer will give rise to gases generated by the fermentation of the beer, and these gases will be held in solution in the beer due to the pressurisation of the interior of the container and the occuptation of the air-space 14 by the membrane 16. The interior of the container 11 will, however be subjected to an increase in pressure and this will be transmitted across the membrane 16 and relieved by operation of the pressure relief valve 37. A small amount of gas can come out of solution in the liquid 1 5 and occupy a proportion of the air-space 14 when this takes place.

Although this embodiment is particularly simple and effective it does have the disadvantage that it occupies a substantial amount of space above the container, and prevents the use of a carrying handle symmetrically located across the diameter of the container. In order to accommodate such a handle, the embodiment of Figure 2 may be used.

In Figure 4 only those components of the valve structure which are to be fitted to a cap such as the cap 18 in Figure 3 are illustrated. Again, the same reference numerals have been used to identify components which fulfil the same or similar functions to corresponding components in the other embodiments illustrated in Figures 1 to 3: in this embodiment the duct corresponding to the duct 19 has two axially spaced annular flanges 39, 40 and, like the duct 19 in the embodiment of Figure 3, a threaded end portion 41. In this embodiment the threaded end portion 41 is fitted through an opening in the cap 1 8 so that the flange 40 rests on the upper surface of the cap 18 in the same manner as the clamping ring 1 8a in the embodiment of Figure 1.A ring nut and washer are then screwed onto the threaded portion 41 to clamp the valve assembly to the cap 1 8. A closed flexible membrane 1 6 is then fitted over the projecting spigot portion of the threaded end of the duct 19 in the same manner as in the embodiment of Figure 3.

Above the flange 39 the duct 19 terminates in a stub spigot which may house a uni-directional valve, shown in broken outline, and identified with the reference numeral 37a. Over the stub spigot 1 9 is fitted a flexible tube 1 9c which terminates in a mouthpiece 38. The mouthpiece 38 may, like the mouthpiece 38 of the embodiment of Figure 1 also incorporate a uni-directional valve whether or not such uni-directional valve is fitted at the position shown in broken outline in the stub spigot 19.

Between the two annular flanges 39, 40 there are formed a ring of radial apertures 42 in the body of the duct 19, and these are closed by a resilient endless band which serves as the pressure relief valve. In fact there need only be one hole and the pressure threshold would then be determined solely by the size of this hole and the tension in the band. When pressure within the interior of the membrane 1 6 exceeds a predetermined pressure, determined by the strength of the band 43, this allows gas to escape through the apertures 42 to the atmosphere.

Reverse flow of air into the membrane 1 6 is, however, securely prevented by the band 43.

A pressure relief of approximately 2 Ibs per square inch pressure is at this time considered suitable, although a different pressure setting may be achieved by suitable variation of the components, for example by fitting a stronger or weaker resilient band 43 or by varying the hole size, to suit particular circumstances.

In the embodiment of Figure 4, if the unidirectional valve 37a is fitted, the flexible tube 1 9c can be made removable so that a carrying handle secured to the top of the vessel 11 can pass easily over the duct 1 9. Indeed, even with the flexible tube 1 9c being pressed down away from handle to be swung over the valve elements, the flexible tube 1 9c being pressed sown away from the position occupied by the handle.

Indeed, it would be possible to dispense with the tube 1 9c altogether and simply make the spigot tube 1 9 in the form of an upwardly directed mouthpiece which a user could blow into directly from above.

Claims (16)

1. Apparatus for use in dispensing a liquid from a vessel, comprising means for introducing a gas into the vessel through a uni-directional valve for retaining gas in the vessel, and a flexible membrane adapted to maintain the introduced gas out of contact with a liquid in the vessel, whereby pressurisation of the vessel can take place without absorption of the gas by the liquid.

2. Apparatus for use in dispensing a liquid from a vessel, which permits a gas to be introduced under pressure into the vessel but which maintains the gas out of physical contact with liquid whereby absorption of the gas by the liquid is prevented.

3. Apparatus for use in dispensing a liquid from a vessel, comprising a membrane adapted to be fitted into the vessel, and a valve for allowing gas to be introduced into the vessel to pressurise the interior thereof; the membrane being so formed in relation to the valve that it isolates liquid in the vessel from contact with the gas introduced through the valve whilst allowing pressure increases due to the presence of the gas to be transmitted to the liquid.

4. Apparatus as claimed in Claim 3, in which the membrane is formed as a closed container or sac for containing gas introduced into the vessel.

5. Apparatus as claimed in Claim 3 or Claim 4, in which the valve is formed as part of a stopper for an opening in the vessel.

6. Apparatus as claimed in any of Claims 3 to 5, in which the valve is formed as a combined unidirectional and pressure relief valve calibrated to relieve the pressure within the vessel when it exceeds a predetermined threshold value.

7. Apparatus as claimed in any of Claims 3 to 6, in which the membrane is both flexible and resilient.

8. Apparatus as claimed in Claim 6 or Claim 7, in which the valve includes a spring loaded ball closing an opening in a resiliently located valve obturator.

9. Apparatus as claimed in any of Claims 3 to 8, in which the means for introducing gas into the container include a gas duct leading to the interior of the container, a uni-directional valve in the duct allowing gas to flow towards the interior of the container, and a pressure relief valve in gas communication with the interior of the membrane allowing gas within the container to exhaust to the atmosphere when the pressure in the interior of the container exceeds a predetermined value.

10. Apparatus as claimed in Claim 9, in which the means for introducing gas into the container also include a length of tubing terminating in a mouthpiece and incorporating, or being associated with, a uni-directional valve allowing gas to be introduced into the vessel on the side of the membrane remote from the liquid.

11. Apparatus as claimed in Claim 9 or Claim 10, in which the pressure relief valve is a flat membrane valve terminating one end of the branch tube.

12. Apparatus as claimed in Claim 9 or Claim 10, in which the pressure relief valve is in the form of a plurality of radial passages in a duct, the passages being closed by a resilient valve member surrounding the duct.

13. Apparatus as claimed in Claim 12, in which the resilient member is an endless band.

14. Apparatus as claimed in any preceding Claim, in which the connection between the membrane and the valve assembly is made by introducing a circumferentially ridged spigot into a neck of the membrane.

1 5. Apparatus as claimed in Claim 14, in which the circumferential ridges of the spigot are constituted by an external screw thread formed thereon.

16. Apparatus as claimed in Claim 15, in which the thread on the spigot are removed over a certain section thereof and an annular groove is provided for receiving the rim of the membrane.

1 7. Apparatus for use in dispensing a liquid from a vessel, substantially as hereinbefore described with reference to Figures 1 and 2 or Figure 3 or Figure 4 of the accompanying drawrings.