Beverage-dispensing system

Abstract

The present invention provides a beverage keg with an interior that is partitioned into an upper ported region and a lower ported region by a flexible partition such that pressure applied to one region is transmitted to the other region whilst keeping the contents of both regions separate. This arrangement ensures that pressurised working fluid entering one region of the keg urges beverage to leave the other region of the keg. The present invention also provides a working-fluid supply system that uses mains water to generate pressurised working fluid, which can then be used to urge a beverage from a beverage keg, such as, but not essentially, the portioned beverage keg of the present invention.

Description

[0001] BEVERAGE-DISPENSING SYSTEM

[0002] Field of the Invention

[0003] The present invention is concerned with dispensing of beverages and in particular systems that use working fluids to urge beverages from beverage containers such as beer kegs.

[0004] Background of the Invention

[0005] It is a common practice to pressurise a beverage container and connect it to an outlet controlled by a tap or valve, so that opening the tap causes the beverage to be dispensed through the outlet. This type of arrangement is commonplace in bars and public houses, where beer is stored in a cellar in a keg which is pressurised sufficiently to propel the beer up from the cellar level to a beer tap on the bar. Pressure in the keg needs to be maintained while the level of the beverage in it falls, and commonly this is done using compressed gas. Typically this propellant gas is carbon dioxide, although nitrogen is also used, as are combinations of both gases.

[0006] Pressurising a beverage in order to dispense it is not only useful on a commercial premises. The same principle is applicable also to small-scale systems for domestic use.

[0007] The use of pre-pressurised gaseous propellants is problematic. Carbon dioxide, the most common choice, is of course an important greenhouse gas. Its use in this context involves carbon dioxide being vented to the atmosphere, which is ecologically highly disadvantageous. In recent years carbon dioxide supply in some markets, such as the UK, has sometimes been uncertain and prices have been high. Cylinders used for supply of gas, be it carbon dioxide or nitrogen, in sufficient quantity are heavy and cumbersome, so that their delivery to, and retrieval from, cellars is an onerous task. There are also safety implications in manual handing of the heavy cylinders which can cause injuries. Given the high pressures at which gases are delivered, cylinder failure can be explosive and highly dangerous. Release of propellant gas in confined spaces such as cellars creates risk of asphyxiation.

[0008] FR2411797A1 , Georges Gruffy, discloses a beer storage system having a container, seemingly in the form of a bag to judge from the drawings, having two compartments, one containing beer and one being for connection to a city water supply. Pressure created by the city water supply enables drawing of the beer.

[0009] EP2025640A1 , Carlsberg Breweries AS, discloses a cooling device for beverages in which a collapsible beer container is housed in a thermally insulating container closable by means of a lid. The container is connectable through a hose to a tap (water source) to pressurise the interior of the container and hence the beer inside the collapsible container.

[0010] EP0513205A1 , AG Patents Ltd., concerns a disposable beverage containerwith a rigid outer bottle containing an impermeable flexible bag containing a beverage to be dispensed. The bottle is connectable to a source of pressurised fluid to pressurise the beverage.

[0011] The prior art described above provides examples of beverage containers connectable directly to a water supply to pressurise them. But in commercial premises serving multiple beverages, direct connection (and subsequent disconnection) of numerous beverage containers such as kegs to the mains supply may be problematic, given that a single leakage could create a costly flood.

[0012] A separate problem with the above prior art systems involving provision of water to the container used to store the beverage is that when the beverage has been dispensed, one is left with a container filled with water. Either this needs to be disposed of, or the heavy, water- filled container needs to be moved elsewhere for reuse or disposal, either option being potentially troublesome.

[0013] Summary of the Invention

[0014] An aim of the present invention is to provide a means of using a pressurised water supply to facilitate dispensing of beverages, which overcomes one or more of these problems. Another aim of the present invention is to provide a beverage container, such as a beverage keg, that is particularly suitable for use with working fluids that have been pressurised using a pressurised water supply.

[0015] To this end, the present invention provides a beverage keg in accordance with claim 1 and a beverage-supply system in accordance with claim 17.

[0016] According to a first aspect of the present invention, there is provided a beverage keg with an interior that is partitioned into a first ported region and a second ported region by a partition, said partition being movable or flexible so that pressure in the one region is transmitted to the other region whilst keeping the contents of both regions separate; said keg further comprising a first valve assembly located at a first end of the keg, said valve assembly configured to connect the ports of the first and second regions to a beverage-supply system so that pressurised working fluid can enter the keg via an inlet pathway and beverage can leave the keg via an outlet pathway; wherein the outlet pathway is in fluid communication with one of said region ports and the inlet pathway is in fluid communication with the other of said region ports; wherein one of the region ports is located proximal to the valve assembly at the first end of the keg and the other region port is located distal to the valve assembly at a second, opposing end of the keg; and wherein the fluid communication between the valve assembly and the distal region port is achieved via by-pass means that extend from the first end of the keg to the second end of the keg.

[0017] In use, one of the interior regions of the keg is filled with a beverage (e.g., beer), such that when a pressurised working fluid enters the second of the interior region of the keg it acts on the partition and pressurises the beverage in the keg without physically coming into contact with the beverage.

[0018] As with conventional beer kegs, the working fluid’s point of ingress and the beverage’s point of egress are located at the same end of the keg (typically the top end). However the beverage keg of the present invention does not employ an internal spear.

[0019] Conventional beer kegs employ an internal spear, which is essentially a conduit that projects from the keg’s outlet to a lower region of the keg’s interior, to provide a route of egress for the keg’s beverage when the keg is pressurised by working fluid entering the top end of keg. The presence of the internal spear is known to present challenges when it comes to cleaning emptied kegs so that they can be reused.

[0020] The partitioned twin-region design of the beverage keg of the present invention employs ported regions at either end of the keg (i.e., the top and the bottom) that retain their respective contents (i.e., beverage or working fluid) separate whilst facilitating a transfer of pressure from the working fluid to the beverage that results in the beverage being dispensed from the keg.

[0021] By-pass means, which are provided outside of beverage receiving interior of the keg, provides the required fluid communication between the keg’s valve assembly (i.e., where the working fluid enters the keg and the beverage leaves the keg) and the distal ported region (i.e., the interior region that is located at the opposite end of the keg).

[0022] Preferably the by-pass means may comprise one or more conduits that connect one of said valve assembly pathways with the distal region port.

[0023] Preferably the first and second region ports are positioned so as to face the partition. One benefit of orienting the region ports in this way is that pressurised working fluid entering the interior of the keg acts directly on the partition. Another benefit is that the displaced partition urges the beverage directly at the outlet of the keg’s interior.

[0024] Further preferably, although not essentially, the first region port, the second region port, or both region ports are positioned in-line with a main central axis of the keg. Additionally or alternatively, the first region port, the second region port, or both region ports may comprise an inverted dome that extends towards the partition and has the port centrally located therein.

[0025] Providing the port at the centre of the inverted dome serves to create an annular space around the top / base of the region that can accommodate the gas / dregs and in so doing mitigate the extent to which such are dispensed from the keg during normal use.

[0026] It is envisaged that, unlike with conventional kegs which employ the spear to limit such unwanted discharges, the use of the inverted dome port means that less beverage is left in the keg because the last of the beverage can be dispensed whilst the dregs are captured in annular space around the dome. In use the flexible partition membrane flexes into contact with the inverted dome and traps the dregs in the annular space around the dome.

[0027] It is also envisaged that because the spear in traditional kegs takes fluid from the bottom of the keg this allows gas to remain at the top of the keg. In the case of the present invention, providing an inverted dome at the top of the keg creates a space to accommodate gas within the keg at a location above the exit point and traps the gas in the annular space.

[0028] Preferably the keg has a twin wall construction with an inner wall, which defines the interior, and an outer wall separated by a clearance space, and whereby the clearance space either accommodates the by-pass means or acts itself as the by-pass means.

[0029] The twin wall construction is considered particularly beneficial because it enables the by-pass means to be protected by outer wall of the keg, thereby rendering the keg more durable.

[0030] Preferably the first ported region is located adjacent to the first valve assembly in a top portion of the keg and the second ported region is located distal to the first valve assembly in a bottom portion of the keg.

[0031] Preferably the outlet pathway of the first valve assembly is in fluid communication with the first region port and the inlet pathway of the first valve assembly is in fluid communication with the second region port. This arrangement is appropriate when the beverage is to be received in the first region at the top of the keg.

[0032] Alternatively the outlet pathway of the first valve assembly is in fluid communication with the second region port and the inlet pathway of the first valve assembly is in fluid communication with the first region port. This arrangement is appropriate when the beverage is to be received in the second region at the bottom of the keg. Preferably the keg may further comprise a second valve assembly located at the second end of the keg, wherein an inlet pathway of the second valve assembly is in fluid communication with said first region port and the outlet pathway of the second valve assembly is in fluid communication with said second region port; and wherein the first and second valve assemblies are configured to receive a return cap that connects the inlet and outlet pathways of that particular valve assembly so that the un-capped valve assembly provides the only route in and out of the beverage keg.

[0033] It is envisaged that providing the keg with a valve assembly at either end provides further benefits to the single valve assembly design described herein. The dual ends enable the keg and / or flexible partition membrane to be inverted, which provides for both easier cleaning and allows the keg to be used again with the regions reversed (i.e., the beverage held in the working fluid region and vice versa).

[0034] Preferably, the keg may comprise two sections that are secured together to form the partitioned interior of the keg. It is envisaged that adopting the two section construction facilitates the installation of the partition. In this regard, it is considered further preferable that the two sections are secured together at a mid-point in the keg and a periphery of the partition is retained between the two sections once they are secured together.

[0035] It is envisaged that alignment means may be provided on the two sections such that the by-pass means can be correctly aligned when the two sections are connected together to form the complete keg. The alignment means may simply comprise markings that need to be aligned when the two sections are connected to one another.

[0036] Preferably the, or each, valve assembly is protected by a protective rim that at least partially encircles the valve assembly and projects away from an end of the keg beyond said valve assembly.

[0037] According to a second aspect of the present invention, there is provided a beveragesupply system with a working-fluid source for supplying a working fluid at pressure above atmospheric to a beverage keg, the working-fluid source comprising: a plurality of vessels that are each at least partly filled with a working fluid in use, said vessels each having a water inlet connectable to a source of pressurised water and a working fluid outlet, so that as water is supplied to the vessels the working fluid is pressurised for output through the respective working fluid outlets of the vessels; wherein the working fluid outlet of each vessel has a unidirectional valve that supplies a distinct holding chamber that is configured to retain working fluid at pressure above atmospheric, whilst selectively permitting working fluid to leave the holding chamber via an uni-directional outlet; wherein the respective holding chamber outlets all supply an accumulation chamber that is configured to retain working fluid at pressure above atmospheric whilst selectively permitting working fluid to leave the accumulation chamber via a uni-directional outlet that is connectable in fluid communication with a beverage keg so that, in use, pressurised working fluid from the working-fluid source urges beverage to be dispensed from said beverage keg.

[0038] It is envisaged that providing an accumulation chamber supplied with pressurised working fluid by the respective holding chambers of multiple vessels greatly reduces the prospects of a reduction in pressure of the working fluid being supplied when one of the vessels is being recharged. The accumulation chamber thereby isolates the pressurised working fluid output from the current status of any one particular vessel.

[0039] Preferably the system comprises control means that selectively open and close the uni-directional outlets between the vessel and the respective holding chamber and / or the respective holding chamber and the accumulation chamber, so as to control the holding chamber(s) supplying the accumulation chamber with pressurised working fluid at any particular time.

[0040] Preferably the working fluid is air. However, it is envisaged that the working-fluid source of the present invention could utilise pressurised water to pressurise a range of working fluids that could then be used to dispense beverage from a beverage container such as a beverage keg. Suitable examples of working fluids include carbon dioxide and carbon dioxide / nitrogen mixes, although other gases considered suitable by the skilled person could also be pressurised by the present invention.

[0041] Preferably the accumulation chamber outlet may be connected to a pressure regulator for providing working fluid to the beverage keg at a controlled pressure.

[0042] Preferably each vessel forms may form an internal cavity that has no partition between the working fluid and the water, and in which the working fluid outlet is disposed in an upper region of the internal cavity. Alternatively, each vessel may form an internal cavity that has a partition between the working fluid and the water.

[0043] Preferably each vessel may further comprise a supply valve controlling supply of water to said vessel, a drain valve controlling a route for draining of water from said vessel, a working fluid inlet valve controlling a route for entry of the working fluid to said vessel.

[0044] Whilst it is envisaged that the supply valve may be constantly open, such that water is continuously supplied to the vessel even when water is being flushed from the vessel (akin to a toilet cistern), it is considered preferable that the supply valve may cut off the water supply when the water is being flushed from the vessel. To this end, further preferably the system may further comprise at least one controller that is responsive to the water levels in said vessels and operates each of said vessels cyclically in at least two different modes: a supply mode in which the drain valve is closed, the working fluid inlet valve is closed, and the supply valve is open to supply water to said vessel; a drain mode, activated in response to water level in said vessel being above a threshold height, in which the supply valve is closed to cut off water supply to said vessel, the working-fluid inlet valve is open to permit entry of the working fluid to said vessel, and the drain valve is open to permit water to drain from said vessel. Said controller preferably comprises a float in each vessel to be raised by the water therein.

[0045] Although it is envisaged that any source of pressuring working fluid may be used to dispense beverage from the beverage keg of the present invention it is also considered preferable that the beverage keg of the first aspect may be used in combination with the working fluid source of the beverage-supply system of the second aspect.

[0046] The present invention also provides a stand-alone working-fluid source for supplying a working fluid at pressure above atmospheric to a beverage keg, said stan-alone working - fluid source being configured to be connectable to a beverage-supply system.

[0047] In a further aspect of the present invention there is provided a beverage keg with an interior that is provided with a first port located in a top region of the keg and a second port in a lower region of the keg; said keg further comprising a valve assembly located adjacent the first port at the top of the keg, said valve assembly configured to connect the first and second ports to a beverage-supply system so that pressurised gas can enter the keg via an inlet pathway and beverage can leave the keg via an outlet pathway; wherein the outlet pathway is in fluid communication with the second port and the inlet pathway is in fluid communication with the first port; wherein the fluid communication between the valve assembly and the second port is achieved via by-pass means that extend from the top region of the keg to the lower region of the keg without passing through the interior; and wherein the lower port comprises an inverted dome that extends into the interior and has the port centrally located therein.

[0048] It is envisaged that the preferred feature described above in relation to single valve assembly beverage kegs could be employed in combination with the non-partitioned beverage keg of this further aspect of the present invention.

[0049] Although the main focus of the present invention is beverage dispensing systems, it is envisaged that the working-fluid source for supplying a working fluid at pressure above atmospheric disclosed herein could be usefully employed in other non-beverage related applications. Examples of which range from dispensing paint in spray painting systems to dispensing scent from pub toilets air fresheners. Brief Description of the Drawings

[0050] Specific embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0051] Figure 1 is a diagrammatic representation of a beverage-supply system according to the present invention;

[0052] Figure 2 is a schematic and sectional representation of a working-fluid source according to the present invention;

[0053] Figure 3 is a schematic and sectional representation of a beverage container according to the present invention;

[0054] Figure 4 shows a first preferred single valve assembly embodiment of a beverage keg in accordance with the present invention;

[0055] Figure 5 shows the progression of the beverage keg of Figure 4 as working fluid displaces the beverage held in the upper region of the keg;

[0056] Figure 6 shows a second preferred single valve assembly embodiment of a beverage keg in accordance with the present invention;

[0057] Figure 7 shows the progression of the beverage keg of Figure 6 as working fluid displaces the beverage held in the lower region of the keg

[0058] Figure 8 shows a first preferred dual valve assembly embodiment of a beverage keg in accordance with the present invention;

[0059] Figure 9 shows the progression of the beverage keg of Figure 8 as working fluid displaces the beverage held in the upper region of the keg;

[0060] Figure 10 shows a second preferred dual valve assembly embodiment of a beverage keg in accordance with the present invention;

[0061] Figure 11 shows the progression of the beverage keg of Figure 10 as working fluid displaces the beverage held in the lower region of the keg;

[0062] Figure 12 shows a preferred embodiment of single valve beverage keg with an inverted dome port; and

[0063] Figure 13 shows a non-partitioned single valve beverage keg with an inverted dome port. Detailed Description of the Preferred Embodiments

[0064] The main components of a beverage-dispensing system according to the invention are represented in Figure 1. A working-fluid source 10 receives pressurised water through a water inlet (shown in Figure 2) and uses it to pressurise a working fluid which is supplied through a conduit 14 via a pressure regulator 16 to a beverage container 18, which is thereby pressurised sufficiently to propel beverage from the beverage container 18 through a beverage line 20 to a tap (or taps) 22 from which the beverage is dispensed.

[0065] Looking at the components of the system in more detail, the working-fluid source 10 represented in Figure 2 comprises at least two vessels in the form of first and second vessels 24a, 24b each defining a respective internal volume 25a, 25b. The water inlet 12 is connected to a source of pressurised water, which may be the mains water supply (i.e., the public water supply).

[0066] The inlet 12 leads to a supply valve 27 which supplies water to both inlet 28a of the first vessel 24a and inlet 28b of the second vessel 24b, except when the water contained in that vessel is being flushed. In the event that both vessels are being flushed at the same time, the supply valve disconnects the water supply from the inlets and connects the inlet 12 to a closed line 30. The inlets 28a, 28b are each in a lower region of their respective vessels 24a, 24b.

[0067] The inlets 28a, 28b may be provided with respective one-way valves arranged to prevent egress of water from the vessels 24a, 24b by these routes, although these are not shown and are not functionally essential.

[0068] Each vessel 24a, 24b has a respective working-fluid outlet 32a, 32b leading via a respective non-return valve 34a, 34b to a respective holding chamber 74a, 74b in which the pressurised working fluid is retained until such time as it is fed into an accumulation chamber 76.

[0069] Controlled uni-directional valve means 75a, 75b are employed to ensure that the pressure of the working fluid in the accumulation chamber 76 is topped up by pressurised working fluid from the holding chambers of each of the vessels 24a, 24b. In this way the accumulation chamber provides a constant uninterrupted supply of pressurised working fluid to the conduit 14 and on to a beverage container connected in fluid communication thereto.

[0070] The working-fluid outlets 32a, 32b are each in an upper region of their respective vessels. In the present embodiment, the working fluid is air. The invention may be implemented using other working fluids, such as carbon dioxide or a carbon dioxide / nitrogen mix. Water or other liquids may be used for this purpose in certain embodiments.

[0071] Water 42a, 42b from the mains supply displaces the working fluid in the vessel 24a, 24b and so raises its pressure. It is not necessary, in the vessel 24a, 24b, to physically separate the water 42a, 42b from the working fluid when it is a gas such as air. The water pools at the bottom of the internal volume 25a, 25b of the vessel. Only the working fluid reaches the working-fluid outlet 32a, 32b, thanks to its positioning in an upper region of the vessel 24a, 24b, above water level 38a, 38b. As the water level 38a, 38b rises, the air in the region above the water is compressed. When pressure in the vessel 24a, 24b reaches a threshold, pressurised air begins to be expelled via the working fluid outlet 32a, 32b into the vessel’s respective holding chamber 74a, 74b. It will be appreciated that the outlets 32a, 32b are necessarily uni-directional so that the working fluid cannot re-enter the vessel from the holding chamber.

[0072] The vessels 24a, 24b must periodically be emptied of water. This needs to be done before the water level 38a, 38b reaches the level of the working-fluid outlet 32a, 32b. A mechanism is provided which is triggered by the water level 38a, 38b reaching a threshold height and which, in response (a) opens a drain valve 44a, 44b in a lower region of the vessel 24a, 24b to allow the water 42a, 42b to flow out, (b) opens an air inlet valve 46a, 46b to admit air to the vessel 24a, 24b, and (c) switches the supply valve 27 so that water is not directed to the inlet 28a, 28b of the draining vessel 24a, 24b.

[0073] When the relevant vessel 24a, 24b has drained of water, its drain valve 44a, 44b and its air inlet valve 46a, 46b are closed before it begins to fill with water again via the inlet 28a, 28b.

[0074] The drain valves 44a, 44b may be configured to permit draining of the water but prevent ingress of water to the vessels 24a, 24b by this route. The air inlet valves 46a, 46b may be formed as one-way valves to permit ingress of air in response to reduced pressure in the vessels 24a, 24b but resist egress of air by these routes.

[0075] Although not shown, it is envisaged that filtration and / or sanitation means may be provided on the air inlet valves to ensure that the air used to form the pressuring working fluid does not introduce pathogens or contaminants into the beverage supply system.

[0076] The vessels 24a, 24b thus each go through a repeated cycle of (a) filling with water and supplying pressurised air (i.e., working fluid) and then (b) draining the water, refilling with air to be compressed. It is preferable that the first and second vessels 24a, 24b are in this respect out of phase. That is, while one vessel is being supplied with water to provide compressed air, the other vessel is in the drain-and-refill phase. Hence for at least some of the time that one vessel 24a, 24b is draining, the other vessel is able to supply pressurised working fluid.

[0077] With that said, the provision of respective holding chambers 74a, 74b for each vessel ensures that the level of working fluid within the accumulation chamber constantly topped up.

[0078] It will be appreciated that by providing the holding chambers 74a, 74b and the accumulation chamber 76 between the source of the pressuring working fluid (i.e. , vessels 24a, 24b) and the recipient the pressuring working fluid (e.g., beverage keg 18) serves to isolate the recipient from any interruptions in supply that occur during a particular vessel’s draining phase. This ensures that the pressurised working fluid supplied by the accumulation chamber 76 to the conduit 14 is maintained at the required level.

[0079] It will be appreciated that providing a uni-directional valve between the various working fluid chambers (i.e., the vessel, the holding chamber and the accumulation chamber) ensures that the system can provide working fluid at an equivalent pressure to the highest level of pressure available from the mains water supply, even if the main water pressure is not maintained at constant pressure.

[0080] Preferably the system comprises flow control means (not shown) between the holding chambers 74a, 74b and the accumulation chamber 76 such that both holding chambers are able to accumulate pressurised working fluid in isolation of the other holding chamber interaction with the accumulation chamber.

[0081] There is a non-trivial advantage to this, in that all the vessels 24 in a given system can themselves accumulate pressure at any given time. This also ensures one is always in reserve.

[0082] It is appreciated that as it is a closed system, water will stop prior to 27 due to back pressure unless taps 22 are opened; wastage of mains water is thus avoided. For this purpose, pressure may be sensed upstream of the pressure regulator 26, to provide a controlled pressure to it, or downstream of the pressure regulator 26, so that the accumulation chamber 76 is accessed only when pressure supplied to the beverage container 18 is below a threshold.

[0083] The mechanism used to control opening and closing of the drain valves 44a, 44b in this embodiment are floats 48a, 48b, which are arranged to be raised when the water level 38a, 38b in the relevant vessel 24a, 24b reaches the threshold height, thereby opening the drain valves so that water can be flushed from the vessel. Although not essential, it is envisaged that the action of raising the floats could also be used to open the air inlet valves 46a, 46b so that the previously displaced working fluid can be replaced.

[0084] Further, the supply valve 27 may also be operated by the action of raising the floats such that the water supply to a particular vessel is temporarily ceased during the draining stage. However, as noted above, this is entirely optional and the water supply to the vessel could be maintained even during the draining stage (e.g., akin to a toilet cistern during a flush).

[0085] The drain valves 44a, 44b lead to a tank 50 (see Figure 1) such as the water storage tank of a commercial venue, from which the water will be reused, so that water need not be wasted. It is envisaged that the captured water could be employed in grey-water uses, such a filling toilet cisterns. If this is not possible, then the drained water can be sent to drain in certain commercial set-ups or domestically.

[0086] It is envisaged that while Figure 1 shows a single beverage container 18, a commercial installation will typically comprise multiple beverage containers 18 supplied with working fluid from a common working-fluid source 10 and supplying beverages to respective taps 22.

[0087] The beverage containers 18 and the working-fluid source 10 may be housed in the cellar of a bar or public house, for example, with the taps 22 of course being on the bar. The working-fluid source 10 may preferably be housed higher in the building to allow drainage of water into a non-pressurised cold water tank or to grey water system / dedicated storage tank.

[0088] Whilst the system of the present invention would typically be employed in a commercial installation, it may also be implemented in small-scale domestic installations, where the facility to use easily available mains water to provide the pressure needed for delivery of the beverage is highly advantageous.

[0089] The beverage supply system and beverage keg of the present invention can make use of conventional keg couplers and plumbing, so that users with experience of conventional cellar systems will not require new skills. It is envisaged that anyone / an experienced user of existing pressurised gas beverage deliver systems would find the operation of the present invention to be a non-task as it requires no steps to be taken by staff compared with existing pressurised gas based systems. Changing kegs would be precisely the same.

[0090] The embodiments depicted and described serve only as examples of the manner in which the invention can be implemented. Numerous variations and modifications are possible without departing from the scope of the invention according to the appended claims. For example, whereas the illustrated embodiment uses a pair of vessels 24a, 24b, other embodiments may have three or more vessels. The vessel 24 may incorporate an element, such as a piston or flexible membrane, to separate the working fluid from the beverage. The working fluid could be something other than air, be it another gas, or a liquid which may be water. Control of the cycle of filling and emptying the vessel 24a, 24b through the activation of float 48a and 48b, the air inlet valves 46a, 46b and the drain valves 44a, 44b may be purely mechanically implemented, or may involve the use of an electronic controller responding to signals from sensors.

[0091] Turning now to the beverage container (i.e., beverage keg) of the present invention reference will now be made to the various preferred embodiments shown in Figures 3 to 12. The various embodiments of the beverage container all share the same key characteristics of a keg with an interior that is partitioned into two regions, each of which holds its contents physically separate from the contents of the keg’s other region.

[0092] The general features of the beverage keg will now be described with reference to the beverage container 18 shown in Figure 3. As can be seen from Figure 3, in the container 18 the working fluid 25 is separated from the beverage 52 so that the two fluids will not be mixed.

[0093] The example beverage container 18 depicted in Figure 3 is in the form of a beer keg having a container vessel 54 whose interior is partitioned by a membrane 56 into two separate and non-communicating regions; namely a working-fluid region 58 and a beverage-containing region 60.

[0094] The membrane 56 is flexible so that the volumes of the two regions 58, 60 are not fixed. The flexible membrane 56, which is formed from a durable yet flexible material that has gas barrier properties, is connected to the container vessel 54 around the circumference of vessel 54.

[0095] One suitable example of the flexible membrane used in the beverage keg of the present invention is composite plastics material form with a triple-layer construction with a high-performance gas barrier, such as ethylene vinyl alcohol (EVOH) or Nylon / MXD6, sandwiched between food-grade, washable plastics, such as polyethylene (PE) or thermoplastic polyurethane (TPU). This composite arrangement effectively preventing gas permeation between the two regions of the keg whilst maintains the partition’s ability to flex towards either end of the keg in response to pressure changes within the two regions.

[0096] It is envisaged that the surface area of the flexible membrane will preferably match the surface area of the keg’s upper / lower inner wall precisely such that when one region of the keg is full of working fluid, and the flexible membrane is at its maximum displacement, the quantity of beverage left in the other region of the keg will be at a minimum - i.e., close to 0. It will be appreciated that attaching the flexible membrane to the keg at a mid-point will ensure that it fits snuggly over either end of the keg, regardless of the profile of the inner wall.

[0097] Pressure in the working-fluid region 58 is thus transmitted to the beverage-containing region 60. As the beverage 52 is dispensed through the beverage line 20 and the beveragecontaining region 60 empties, the working-fluid region 58 correspondingly expands.

[0098] The beverage container 18 has a connector 62, which comprises a valve assembly, that forms a working-fluid connection (i.e., an inlet pathway) for supply of working fluid from the conduit 14 to the working-fluid region 58 and a beverage-supply connection (i.e., an outlet pathway) for supply of the beverage 52 from the beverage-containing region 60 to the beverage line 20.

[0099] The connector 62 may be threadedly received on a neck of the container vessel and can be removed for cleaning and refilling of the beverage container 18. These aspects are not depicted in detail herein but are in themselves conventional. The well-known Sankey® type coupler may be used although other commonly employed couplers could alternatively be used. The beverage container 18 in Figure 3 has a neck at only one end, but in other embodiments these may be provided at both ends (see Figures 8 to 11).

[0100] In the embodiment shown in Figure 3, a route for supply of working fluid to the workingfluid region 58 is provided by virtue of a twin-walled structure. Outside the container vessel 54 is an outer vessel 68 and a passage 70 between the two that conducts the working fluid via a transfer inlet 72 to the working-fluid region 58. The route for supply of working fluid to the working-fluid region 58 may in other embodiments simply comprise a tube.

[0101] Further preferred elements of the beverage keg of the present invention will now be described with reference to the various embodiments shown in Figures 4 to 12.

[0102] Figure 4 shows a twin-walled beverage keg 80 formed with an inner wall 81 and an outer wall 82 spaced apart by a clearance. The inner wall 81 and the outer wall 82 are preferably formed from metal, such as aluminium or steel, or a suitable plastic, such as food grade HDPE, PET to ensure that the keg retains its structure despite the above atmospheric pressure of the keg’s contents.

[0103] The interior of the keg, as defined by the inner wall 81 , is partitioned into two separate regions 84, 85 by a flexible partition membrane 83. The periphery of the flexible partition membrane 83 is secured in position within the interior of the keg such that it can be displaced in either direction as a result of a pressure differential between regions 84 and 85 whilst ensuring that two regions and their contents remain separate from one another. The keg is provided with a valve assembly 87 at one end thereof, which practically speaking would generally be considered the top end of the keg. The valve assembly 87 is used to connect the keg to a beverage supply system, such as that shown in Figure 1.

[0104] The valve assembly 87 comprises an outlet pathway 88, through which the stored beverage is dispensed, and an inlet pathway 89, through which the pressurised working fluid from a working fluid source (such as working fluid source 10) can enter the keg so as to displace the beverage.

[0105] Each valve assembly pathway is in fluid communication with one of the keg’s interior regions. Specifically, in the embodiment shown in Figure 4, the outlet pathway 88 is in fluid communication with the upper ported region 84, wherein the beverage is held, via region port 84a. The inlet pathway 89, on the other hand, is connected in fluid communication with the region port 85a or the lower ported region 85 via by-pass means 86 provided in the clearance between the inner and outer walls of the keg.

[0106] In order to provide some protection to the valve assembly 87 at the top of the keg, the outer wall 82 of the keg is provided with a protective rim 90 that encircles the valve assembly and also projects beyond the valve assembly.

[0107] The flow of working fluid through the keg is depicted in Figure 4 as a dashed line, whereas the flow of beverage is depicted as a dotted line. Against this backdrop and with additional reference to Figure 5 the operation of this preferred beverage keg 80 will now be described in more detail.

[0108] Figure 5 shows the life cycle of the beverage keg 80, which begins with a beverage (i.e., beer) filed upper ported region substantially filling the interior of the keg. At this stage the membrane 83 has been displaced by the volume of beer 52 placed in the keg using conventional filling methods. This is possible because the valve assembly of the keg is compatible with systems.

[0109] Once connected to the working-fluid source 10 of a beverage system the flow of pressurised working fluid into the lower ported region 85 of the keg begins as soon as a demand for beer is made from the tap 22.

[0110] As the beer 52 leaves the keg 80 to fill a thirsty customer’s glass (not shown) the working fluid displaces the flexible membrane 83 upwards. This movement of the flexible membrane serves to decrease the volume of the upper ported region 84 so as to maintain the pressure on the beer that remains. As beer continues to be dispensed from the keg the volume of working fluid 25 in the lower ported region increases, until such time that the working fluid filled lower ported region substantially fills the interior of the keg. Once this point is reached the exhausted keg can be exchanged for a beer filed keg and then sent off for cleaning and reuse.

[0111] Turning now to Figure 6, which shows an alternative embodiment single beverage keg 180.

[0112] Once again the twin-walled beverage keg 180 is formed with an inner wall 181 and an outer wall 182 spaced apart by a clearance. The inner wall 181 and the outer wall 182 are preferably formed from metal, such as aluminium or steel, or a suitable plastic, such as food grade High-density polyethylene (HDPE) or Polyethylene terephthalate (PET) to ensure that the keg retains its structure despite the above atmospheric pressure of the keg’s contents.

[0113] The interior of the keg, as defined by the inner wall 181 , is partitioned into two separate regions 184, 185 by a flexible partition membrane 183. The periphery of the flexible partition membrane 183 is secured in position within the interior of the keg such that it can be displaced in either direction as a result of a pressure differential between regions 184 and 185 whilst ensuring that two regions and their contents remain separate from one another.

[0114] The keg is provided with a single valve assembly 187 at one end thereof (i.e. , the top end of the keg). Once again the valve assembly 187 is used to connect the keg to a beverage supply system, such as that shown in Figure 1.

[0115] The valve assembly 187 comprises an outlet pathway 188, through which the stored beverage is dispensed, and an inlet pathway 189, through which the pressurised working fluid from a working fluid source (such as working fluid source 10) can enter the keg so as to displace the beverage.

[0116] As before, each valve assembly pathway is in fluid communication with one of the keg’s interior regions. However, in the embodiment shown in Figure 6, the inlet pathway 189 is connected in fluid communication with the region port 184a of the upper ported region 184.

[0117] Conversely, the outlet pathway 188 makes fluid communication with the region port 185a of the lower ported region, where the beverage is stored, via by-pass means 186, which are again provided in the clearance between the inner and outer walls of the keg.

[0118] Once again, the outer wall 182 of the keg 180 is provided with a protective rim 190 that encircles the valve assembly and also projects beyond the valve assembly in order to protect it from being knocked or otherwise damaged. Figure 7 shows the life cycle of the beverage keg 180, which begins with a beverage (i.e. , beer) filed lower ported region substantially filling the interior of the keg. At this stage the membrane 183 has been displaced by the volume of beer 52 placed in the keg using conventional filling methods. This is possible because the valve assembly of the keg is compatible with systems. It will be appreciated that the by-pass means 186, provided in the clearance between the inner and out walls of the keg, enable the beer to be delivered into keg.

[0119] Once connected to the working-fluid source 10 of a beverage system the flow of pressurised working fluid into the upper ported region 184 of the keg begins as soon as a demand for beer is made from the tap 22.

[0120] As the beer 52 leaves to keg 180 to fill another thirsty customer’s glass (not shown) the working fluid displaces the flexible membrane 183 downwards. This movement of the flexible membrane serves to decrease the volume of the lower ported region 185 so as to maintain the pressure on the beer that remains.

[0121] As beer continues to be dispensed from the keg the volume of working fluid 25 in the upper ported region increases, until such time that the working fluid filled upper ported region substantially fills the interior of the keg. Once this point is reached the exhausted keg can exchanged for a beer filed keg and then sent off for cleaning and reuse.

[0122] It is envisaged that additional functionality may be achieved by providing a valve assembly at either end of the beverage keg of the present invention. That is to say, a valve assembly is provided at the top and bottom ends of the keg.

[0123] Figure 8 shows a twin-walled beverage keg 280 formed with an inner wall 281 and an outer wall 282 spaced apart by a clearance. The inner wall 281 and the outer wall 282 are preferably formed from metal, such as aluminium or steel, or a suitable plastic, such as food grade HDPE, PET to ensure that the keg retains its structure despite the above atmospheric pressure of the keg’s contents.

[0124] The interior of the keg, as defined by the inner wall 281 , is partitioned into two separate regions 284, 285 by a flexible partition membrane 283. Once again the periphery of the flexible partition membrane 283 is secured in position within the interior of the keg such that it can be displaced in either direction as a result of a pressure differential between regions 284 and 285 whilst ensuring that two regions and their contents remain separate from one another.

[0125] The keg is provided with a first valve assembly 287 at a first end thereof, and a second valve assembly 291 at a second, opposite end of the keg 280. Effectively a valve assembly is provided on the top and bottom ends of the keg. Each valve assembly 287, 291 is essentially identical and comprises an outlet pathway, through which the stored beverage is dispensed, and an inlet pathway, through which the pressurised working fluid from a working fluid source (such as working fluid source 10) can enter the keg so as to displace the beverage.

[0126] However, as only one of the valve assemblies is ever connected to a beverage-supply system at any one time, the other valve assembly is short circuited. This is achieved by the removeable cap 294 which, once secured to a valve assembly, serves to form a fluid communication between the inlet and outlet pathways of said valve assembly.

[0127] In the arrangement shown in Figure 8 the cap 294 is configured to engage with the inlet and outlet pathways of the valve assembly, in a similar way to a standard coupler would such that it is secured to the second valve assembly 291 and the cap is not dislodged by the increased fluid pressures within the keg. The cap 294 acts to redirect any fluids that flow through the inlet pathway 293 back through the outlet pathway 292 of the valve assembly.

[0128] Consequently, the first valve assembly inlet pathway 289 achieves fluid communication with the lower ported region 285 via the by-pass means 286, the capped off second valve assembly 291 and the region port 285a. Meanwhile the first valve outlet pathway 288 is in fluid communication with the beverage containing upper ported region via region port 284a.

[0129] This arrangement enables pressurised working fluid to enter the lower region 285 of the keg and urge the flexible membrane 283 upwards with the result of beverage being dispensed from the upper region 284 via the first valve assembly outlet pathway.

[0130] As previously described for the other embodiments of the beverage keg, the outer wall 282 of the keg is provided with a protective rim 290. As a valve assembly is provided on both ends of the keg, so too are the protective rims that encircle and project beyond the valve assembly.

[0131] Figure 9 shows the life cycle of the beverage keg 280, which begins with a beverage (i.e. , beer) filed upper ported region substantially filling the interior of the keg. At this stage the membrane 283 has been displaced by the volume of beer 52 placed in the keg using conventional filling methods. This is possible because the valve assembly of the keg is compatible with systems.

[0132] Once connected to the working-fluid source 10 of a beverage system the flow of pressurised working fluid into the lower ported region 285 of the keg begins as soon as a demand for beer is made from the tap 22. As the beer 52 leaves to keg 280 the working fluid displaces the flexible membrane 283 upwards. This movement of the flexible membrane serves to decrease the volume of the upper ported region 284 so as to maintain the pressure on the beer that remains.

[0133] As beer continues to be dispensed from the keg the volume of working fluid 25 in the lower ported region increases, until such time that the working fluid filled lower ported region substantially fills the interior of the keg. Once this point is reached the exhausted keg can exchanged for a beer filed keg and then sent off for cleaning and reuse.

[0134] Figure 10 shows an alternative arrangement of the twin-walled beverage keg wherein the beverage receiving region is located at the bottom end of the keg rather than the top. The keg 380 formed with an inner wall 381 and an outer wall 382 spaced apart by a clearance. The inner wall 381 and the outer wall 382 are preferably formed from metal such as aluminium or steel, or a suitable plastic, such as food grade HDPE, PET to ensure that the keg retains its structure despite the above atmospheric pressure of the keg’s contents.

[0135] The interior of the keg, as defined by the inner wall 381 , is partitioned into two separate regions 384, 385 by a flexible partition membrane 383. As with the other described embodiments, the periphery of the flexible partition membrane 383 is preferably secured in position within the interior of the keg such that it can be displaced in either direction as a result of a pressure differential between regions 384 and 385 whilst ensuring that two regions and their contents remain separate from one another.

[0136] The keg is provided with a first valve assembly 387 at a first end thereof, and a second valve assembly 391 at a second, opposite end of the keg 380. As with the keg shown in Figure 8, a valve assembly is provided on the top and bottom ends of the keg.

[0137] Each valve assembly 387, 391 is essentially identical and comprises an outlet pathway, through which the stored beverage is dispensed, and an inlet pathway, through which the pressurised working fluid from a working fluid source (such as working fluid source 10) can enter the keg so as to displace the beverage.

[0138] As in the dual valve assembly keg described above with reference to Figure 8, a removeable cap 394 is secured to one of the valve assemblies in order to form a fluid communication between the inlet and outlet pathways of said valve assembly that essentially short circuits the valve assembly.

[0139] As in the arrangement shown in Figure 8, the cap 394 is secured to the second valve assembly 391 by suitable means (as described above) to ensure that the cap is not dislodged by the increased fluid pressures within the keg 380. As previously explained the cap 394 redirects any fluids (e.g., working fluid or beverage) that flow through the inlet pathway 393 back through the outlet pathway 392 of the valve assembly 391.

[0140] In the preferred embodiment shown in Figure 10 the above arrangement enables the first valve assembly outlet pathway 388 to achieve fluid communication with the beverage containing lower ported region 385 via the by-pass means 386, the capped off second valve assembly 391 and the region port 385a. Meanwhile the first valve inlet pathway 389 is in fluid communication with the upper ported region 384 via region port 384a.

[0141] This arrangement enables pressurised working fluid to enter the upper region 384 of the keg and urge the flexible membrane 383 downwards with the result of beverage being dispensed from the lower region 385 through the first valve assembly outlet pathway via the capped off second valve assembly 391 and the by-pass means 386.

[0142] As previously described for the other embodiments of the beverage keg, the outer wall 382 of the keg is provided with a protective rim 390. As a valve assembly is provided on both ends of the keg, so too are the protective rims that encircle and project beyond the valve assembly.

[0143] Figure 11 shows the life cycle of the beverage keg 380, which begins with a beverage (i.e. , beer) filed lower ported region substantially filling the interior of the keg. At this stage the membrane 383 has been displaced by the volume of beer 52 placed in the keg using conventional filling methods. This is possible because the valve assembly of the keg is compatible with systems. Further, the capped off valve assembly and the by-pass means ensure that the beverage is delivered to the lower region of the keg.

[0144] Once connected to the working-fluid source 10 of a beverage system the flow of pressurised working fluid into the upper ported region 384 of the keg begins as soon as a demand for beer is made from the tap 22.

[0145] As the beer 52 leaves to keg 380 for ‘last orders’ at the bar, the working fluid displaces the flexible membrane 383 upwards. This movement of the flexible membrane serves to decrease the volume of the lower ported region 385 so as to maintain the pressure on the beer that remains.

[0146] As beer continues to be dispensed from the keg the volume of working fluid in the upper ported region increases, until such time that the working fluid filled upper ported region substantially fills the interior of the keg. Once this point is reached the exhausted keg can exchanged for a beer filed keg and then sent off for cleaning and reuse. The above described embodiments of the beverage keg can be categorised as upper beverage storage kegs or lower beverage storage kegs. It is appreciated that there are benefits to both the upper and lower beverage storage kegs.

[0147] When beverage is stored in the upper region of the keg, as is the case in the embodiments shown in Figures 4 and 8, carbonated beverages are dispensed from the top of the liquid level first, allowing any excess gas above to be expelled immediately. Since gas is often experienced at bar taps when kegs are changed, this is expected and helps prevent excessive fobbing, during dispensing. Fobbing is when excess foaming of the beer is caused by the rapid release of carbon dioxide (i.e., a dispensing working fluid) and is undesirable because it leads to wasted beer.

[0148] Additionally, as the flexible membrane is forced upwards, any dregs present will settle to the sides between the membrane and inner wall of the keg. As a consequence liquid dispensed will yield more than other kegs because it removes the need to leave a portion of dregs containing beer within the keg.

[0149] When beverage is stored in the lower region of the keg, as is the case in the embodiments shown in Figures 6 and 10, the liquid is expelled from the bottom first, ensuring that no additional fobbing occurs. Any excess gas is dispensed last, maximising liquid yield and achieving closer to 100% utilisation compared to other keg designs. Small amounts of dregs, if present, are naturally expelled first or gradually throughout dispensing. This setup may be preferable for certain beverage types. Beer may collect in the lower section due to natural drainage, gravity effects, or a sump feature, which improves overall yield. Additionally, the annular space around the inverted dome can serve as a settling zone for sediment, enhancing clarity in unfiltered beverages.

[0150] Figure 12 shows a further preferred feature of the beverage keg of the present invention, which it is envisaged could be employed in the region ports of any of the above described beverage kegs in order to further enhance the efficiency of the beverage keg.

[0151] It should be appreciated that, for the sake of clarity, the keg 480 shown in Figure 12 does not necessarily include all of the features required for a fully functioning keg. However, the skilled person will appreciate how the described features can be combined with the previously described embodiments.

[0152] Turning now to Figure 12, a twin-walled keg 480 is defined by an inner wall 481 and an outer wall 482. A flexible membrane partition 483 (shown in a displaced state) is secured within the interior of keg to define an upper ported region 484 and a lower ported region 485. The interior of the keg defined by the inner wall is provided with curved upper and lower ends. Whilst this curvature of the upper and lower ends of the keg’s interior is not considered essential, it is considered preferable because it reduces the amount of dead space within the keg’s interior that cannot be reached by the displaced flexible membrane partition.

[0153] With that said, it is considered beneficial that at least the area around the upper region port 484a is shaped as an inverted dome that extended towards the flexible membrane partition.

[0154] Providing the region port at the centre of the inverted dome serves to create an annular space around the top the region that can accommodate the gas / dregs and in so doing mitigate the extent to which such are dispensed from the keg during normal use.

[0155] It is envisaged that, unlike with conventional kegs which employ the spear to limit such unwanted discharges, the use of the inverted dome port means that less beverage is left in the keg because the beverage can be dispensed whilst the dregs are captured in annular space around the dome.

[0156] It is appreciated that both region ports of the beverage keg of the present invention may comprise an inverted dome configuration. Indeed, this is considered particularly appropriate in dual valve assembly variants of the beverage keg.

[0157] It is envisaged that the dregs containment benefits provided by locating an inverted dome around a port at the lower end of a beverage keg may be realised in all of the embodiments of partitioned beverage kegs of the present invention. However it is also envisaged that the dreg containment benefits may be achieved in non-partitioned beverage kegs that have a beverage outlet port located at their lower end.

[0158] By way of example, Figure 13 show a non-partitioned version of the beverage keg shown in Figure 6 in the form of beverage keg 580. The keg 580 is once again formed in a twin-walled construction with an inner wall 581 and an outer wall 582 spaced apart by a clearance. As before, the inner and outer walls are preferably formed from metal, such as aluminium or steel, or a suitable plastic, such as food grade High-density polyethylene (HDPE) or Polyethylene terephthalate (PET) to ensure that the keg retains its structure despite the above atmospheric pressure of the keg’s contents.

[0159] In the absence of a partition the interior of the keg, as defined by the inner wall 581 , comprises a single region in which the beverage 52 is held.

[0160] The keg is provided with a single valve assembly 587 at one end thereof (i.e. , the top end of the keg) that is used to connect the keg to a traditional carbon dioxide based beverage supply system. It is appreciated that in the absence of the partition the working fluid necessarily comes into direct contact with the beverage and thus it is appropriate to use carbon dioxide (or a carbon dioxide / nitrogen mix) to dispense the beverage.

[0161] The valve assembly 587 comprises an outlet pathway 588, through which the stored beverage is dispensed, and an inlet pathway 589, through which the pressurised carbon dioxide can enter the keg so as to displace the beverage.

[0162] As before, each valve assembly pathway is in fluid communication with a port at one of the keg’s ends. However, in the absence of a partition the opposing ports feed into a single region, with the inlet pathway 589 is connected in fluid communication with the upper port 584 at the top of the keg.

[0163] Conversely, the outlet pathway 588 makes fluid communication with the lower port 585 at the lower end of the keg, via by-pass means 586, which are again provided in the clearance between the inner and outer walls of the keg. The lower port 585 is surrounded by in inverted dome 583 that extends into the interior of the keg.

[0164] The inverted dome 583 creates an annular space around the lower port 585 that can accommodate the dregs of the beverage, so that a greater proportion of beverage can be extracted from the keg without dregs in it.

[0165] Also, it is envisaged that valve assembly or assemblies of the beverage keg of the present invention may be provided with filtration means to ensure that the working fluid used to displace the beverage from the keg does not introduce pathogens or contaminants into the beverage keg as the working fluid fills the keg.

[0166] It is also envisaged that before filling the keg with a beverage, it may be beneficial to inject an inert gas into one or both of the keg’s inner regions in order to sanitise them prior to filling the keg with a beverage.

Claims

CLAIMS1 . A beverage keg with an interior that is partitioned into a first ported region and a second ported region by a partition, said partition being movable or flexible so that pressure in the one region is transmitted to the other region whilst keeping the contents of both regions separate; said keg further comprising a first valve assembly located at a first end of the keg, said valve assembly configured to connect the ports of the first and second regions to a beveragesupply system so that pressurised working fluid can enter the keg via an inlet pathway and beverage can leave the keg via an outlet pathway; wherein the outlet pathway is in fluid communication with one of said region ports and the inlet pathway is in fluid communication with the other of said region ports; wherein one of the region ports is located proximal to the valve assembly at the first end of the keg and the other region port is located distal to the valve assembly at a second, opposing end of the keg; and wherein the fluid communication between the valve assembly and the distal region port is achieved via by-pass means that extend from the first end of the keg to the second end of the keg.

2. The beverage keg of claim 1 , wherein the by-pass means comprise one or more conduits that connect one of said valve assembly pathways with the distal region port.

3. The beverage keg of claim 1 or 2, wherein the first and second region ports are positioned so as to face the partition.

4. The beverage keg of claim 3, wherein the first region port, the second region port, or both region ports are positioned in-line with a main central axis of the keg.

5. The beverage keg of claim 3 or 4, wherein the first region port, the second region port, or both region ports comprises an inverted dome that extends towards the partition and has the port centrally located therein.

6. The beverage keg of any one of claims 1 to 5, wherein the keg has a twin wall construction with an inner wall, which defines the interior, and an outer wall separated by a clearance space, and whereby the clearance space either accommodates the by-pass means or acts itself as the by-pass means.

7. The beverage keg of any one of claims 1 to 6, wherein the first ported region is located adjacent to the first valve assembly in a top portion of the keg and the second ported region is located distal to the first valve assembly in a bottom portion of the keg.

8. The beverage keg of claim 7, wherein the outlet pathway of the first valve assembly is in fluid communication with the first region port and the inlet pathway of the first valve assembly is in fluid communication with the second region port.

9. The beverage keg of claim 8, wherein the first region contains a beverage.

10. The beverage keg of claim 7, wherein the outlet pathway of the first valve assembly is in fluid communication with the second region port and the inlet pathway of the first valve assembly is in fluid communication with the first region port.11 . The beverage keg of claim 10, wherein the second region contains a beverage.

12. The beverage keg of claim 8, further comprising a second valve assembly located at the second end of the keg, wherein an inlet pathway of the second valve assembly is in fluid communication with said first region port and the outlet pathway of the second valve assembly is in fluid communication with said second region port; and wherein the first and second valve assemblies are configured to receive a return cap that connects the inlet and outlet pathways of that particular valve assembly so that the uncapped valve assembly provides the only route in and out of the beverage keg.

13. The beverage keg of any one of claims 1 to 12, wherein the keg comprises two sections that are secured together to form the partitioned interior of the keg.

14. The beverage keg of claim 13, wherein the two sections are secured together at a mid-point in the keg and a periphery of the partition is retained between the two sections once they are secured together.

15. The beverage keg of any one of claims 1 to 14, wherein the, or each, valve assembly is protected by a protective rim that at least partially encircles the valve assembly and projects away from an end of the keg beyond said valve assembly.

16. A beverage-supply system with a working-fluid source for supplying a working fluid at pressure above atmospheric to a beverage keg, the working-fluid source comprising: a plurality of vessels that are each at least partly filled with a working fluid in use, said vessels each having a water inlet connectable to a source of pressurised water and a working fluid outlet, so that as water is supplied to the vessels the working fluid is pressurised for output through the respective working fluid outlets of the vessels; wherein the working fluid outlet of each vessel has a uni-directional valve that supplies a distinct holding chamber that is configured to retain working fluid at pressure above atmospheric whilst selectively permitting working fluid to leave the holding chamber via an unidirectional outlet; wherein the respective holding chamber outlets all supply an accumulation chamber that is configured to retain working fluid at pressure above atmospheric whilst selectively permitting working fluid to leave the accumulation chamber via a uni-directional outlet that is connectable in fluid communication with a beverage keg so that, in use, pressurised working fluid from the working-fluid source urges beverage to be dispensed from said beverage keg.

17. A beverage-supply system of claim 16, further comprising control means that selectively open and close the uni-directional outlets between the vessel and the respective holding chamber and / or the respective holding chamber and the accumulation chamber, so as to control the holding chamber(s) supplying the accumulation chamber with pressurised working fluid at any particular time.

18. A beverage-supply system of claim 16 or 17, wherein the working fluid is air.

19. A beverage-supply system of any one of claims 16, 16 or 18, wherein the accumulation chamber outlet is connected to a pressure regulator for providing working fluid to the beverage keg at a controlled pressure.

20. A beverage-supply system of any one of claims 16 to 19, wherein each vessel forms an internal cavity that has no partition between the working fluid and the water, and in which the working fluid outlet is disposed in an upper region of the internal cavity.

21. A beverage-supply system of any one of claims 16 to 19, wherein each vessel forms an internal cavity that has a partition between the working fluid and the water.

22. A beverage-supply system of any one of claims 16 to 21 , wherein each vessel further comprises a supply valve controlling supply of air out of said vessel, a drain valve controlling a route for draining of water from said vessel, a working fluid inlet valve controlling a route for entry of the working fluid to said vessel.

23. A beverage-supply system of claim 22, further comprising at least one controller that is responsive to the water levels in said vessels and operates each of said vessels cyclically in at least two different modes: a supply mode in which the drain valve is closed, the working fluid inlet valve is closed, and the supply valve is open to supply water to said vessel; a drain mode, activated in response to water level in said vessel being above a threshold height, the working-fluid inlet valve is open to permit entry of the working fluid to said vessel, and the drain valve is open to permit water to drain from said vessel.

24. A beverage-supply system of claim 23, in which, when the system is in the drain mode, the supply valve is also closed to cut off water supply to said vessel.

25. A beverage-supply system of claim 23 or 24, wherein the controller comprises a float in each vessel to be raised by the water therein.

26. A beverage-supply system of any one of claims 16 to 25, further comprising at least one beverage keg according to any of claims 1 to 15 attached in fluid communication to accumulation chamber outlet of the working-fluid source.

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