Abstract:
The present invention relates to a refillable keg assembly for use in dispensing beverages, in particular beer. The keg assembly comprises an outer shell, and a collapsible container for holding the beverage, positionable within the outer shell. A sealed cavity is defined between the outer shell and the collapsible container. A beverage outlet from the collapsible container enables beer to be dispensed from the keg assembly, and a gas valve allows gas to enter the cavity. The pressure in the container is maintained above atmospheric pressure, and when dispensing the beverage, pressure in the cavity collapses the collapsible container and forces the beverage out through the beverage outlet. A gas compressor is connected to the gas valve, and is activated by a pressure switch to maintain the pressure within the cavity. To refill the keg assembly, the collapsible container can be replaced, and a new collapsible container filled while within the outer shell.

Description:
PRIORITY CLAIM 
     This application claims priority from Australian Patent Application No 2009903325, the entire contents of which are hereby incorporated by reference. 
     FIELD OF THE INVENTION 
     The present invention relates to container and apparatus for dispensing a beverage. The present invention will be described with particular reference to dispensing beer, although the invention may have broader application. 
     BACKGROUND OF THE INVENTION 
     Carbonated beverages, such as beer, are commonly stored in large volume containers and then dispensed to glasses or cups for consumption. Beer is often stored under pressure in a large volume metal keg (e.g. 50 liters). Kegs are artificially pressurised after fermentation using carbon dioxide, or sometimes a mixture of carbon dioxide and nitrogen gas. A typical keg has a single opening in the centre of its top, to which a flow pipe is attached. Pressure in the keg then drives the beer to the dispensing tap. 
     Smaller volume kegs (e.g. 5 liters) are sometimes also used, and are often termed “mini-kegs”. Mini-kegs may pour from the bottom using gravity, or they may comprise a low cost pressurised tap allowing the beer to be dispensed. These mini-kegs tend to be single use devices, which are used by the consumer and not refilled—indeed, they are generally designed not be refilled and reused. However, these mini-kegs also often have problems in that the pressure provided by the tap or by gravity is often insufficient to provide a satisfying pour. Furthermore, reuse of a mini-keg would often exacerbate the problem of the difficulty in maintaining pressure within the mini-keg—it may be difficult for a home user to satisfactorily refill the keg under adequate pressure. 
     It is an object of the present invention to reduce or eliminate some or all of the disadvantages of conventional kegs and mini-kegs, or at least to provide an alternative to these conventional containers. 
     SUMMARY OF THE INVENTION 
     Accordingly, in a first aspect of the present invention, there is provided a refillable keg assembly for a beverage, comprising:
         an outer shell;   a collapsible container for holding the beverage, positionable within the outer shell;   a sealed cavity defined between the outer shell and the collapsible container;   a beverage outlet from the collapsible container; and   a gas valve for allowing gas to enter the cavity,   whereby, when dispensing the beverage, pressure in the cavity collapses the collapsible container and forces the beverage out through the beverage outlet.       

     For dispensing the beverage from the keg assembly, the keg assembly can be connected to a dispensing device, which provides a tap having a tap handle and a tap faucet, and a gas compressor. A beverage conduit connects the beverage outlet to the tap, and a gas conduit connects the gas compressor to the gas valve. The gas compressor maintains the pressure in the sealed cavity, to a pressure above the external atmospheric pressure. Upon operation of the tap handle, the beverage is forced out of the collapsible container, flows through the beverage outlet and is dispensed via the tap faucet. This reduces the volume of the bag, reducing the pressure in the cavity, which in turn triggers a pressure activating switch for the compressor. Gas from the compressor is accordingly forced through the gas valve, into the sealed cavity, which maintains the pressure within the cavity and (at least whilst the tap is open) continues to collapse the collapsible container. In this way, the beverage is squeezed out of the collapsible container, through the beverage outlet, to the tap faucet. 
     The beverage within the collapsible container is kept at a relatively constant pressure—as the beverage is dispensed, the container collapses and its volume accordingly decreases. This helps maintain carbonation within carbonated beverages such as beer, and also helps ensure that the dispensing pressure allows for a satisfying pour. 
     Preferably, the collapsible container is disposable and replaceable. Therefore, once it has been emptied, the empty container can be discarded and a new container can simply be attached to gas and beverage valves and placed the within the outer shell. The collapsible container may therefore be adapted for detachable sealing connection to the outer shell. For example, the container may comprise a connecting component having an aperture which sealingly connects to a nozzle on or attached to the outer shell. The nozzle may be provided by a cap on the outer shell. 
     A flow constrictor, such as a helical channel, may be used to restrict the flow of the beverage through the beverage outlet. However, there may also be a relief valve provided to allow gas to escape from the collapsible container—this relief valve should allow the gas to escape independently of the flow constrictor, allowing the ready release of pressure from within the collapsible container, if required. 
     In a second aspect of the present invention, there is provided a dispensing device for connection to the keg assembly of the first aspect of the present invention. The dispensing device may comprise a tap having a tap handle and a tap faucet, the tap connected to the beverage outlet of the keg assembly, and a gas compressor in fluid connection with the gas valve of the keg assembly. A pressure activating switch may be provided which triggers the compressor upon a decrease of pressure within the cavity, such that as the beverage is dispensed, the compressor forces gas through the gas valve of the keg assembly. It accordingly helps force the beverage through the beverage outlet of the keg assembly to the tap faucet, and maintain the beverage pressure within the collapsible container. The dispensing device may also chill the beverage. 
     In a third aspect of the present invention, there is provided a keg for connection to a replaceable, collapsible container for holding a beverage, the collapsible container located in use within the keg and defining a sealed cavity between an outer wall of the bag and an inner wall of the keg, the keg comprising:
         a beverage outlet for allowing the beverage to flow from the collapsible container; and   a gas valve for allowing gas to enter the cavity,   whereby, when dispensing the beverage, pressure in the cavity collapses the collapsible container and forces the beverage out through the beverage outlet.       

     In a fourth aspect of the present invention, there is provided a method of refilling a beer keg, comprising:
         removing an emptied collapsible container from within the beer keg;   inserting a new collapsible container into the beer keg; and   filling the new collapsible container.       

     A detailed description of one or more preferred embodiments of the invention is provided below along with accompanying figures that illustrate by way of example the principles of the invention. While the invention is described in connection with such embodiments, it should be understood that the invention is not limited to any embodiment. 
     For the purpose of example, numerous specific details are set forth in the following description in order to provide a thorough understanding of the present invention. However, the present invention may be practiced without some or all of these specific details. For the purpose of clarity, technical material that is known in the technical fields related to the invention has not been described in detail so that the present invention is not unnecessarily obscured. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       An illustrative embodiment of the present invention will be discussed with reference to the accompanying drawings wherein: 
         FIG. 1  is a schematic cross-section of a keg according to an embodiment of the present invention; 
         FIG. 2  is a perspective view of a keg according to an embodiment of the present invention; 
         FIG. 3  is a cross-section of the keg of  FIG. 2 ; 
         FIG. 4  is a cross-section of the keg of  FIG. 2 , with only the first and second keg cap components; 
         FIG. 5  is a perspective view of a third keg cap component for the keg of  FIG. 2 ; 
         FIG. 6  is a perspective view of a fourth keg cap component for the keg of  FIG. 2 ; and 
         FIG. 7  is an underside perspective view of a fifth keg cap component for the keg of  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to the figures, there is shown a keg assembly  10  according to an embodiment of the present invention. This keg assembly  10  is intended to be able to contain approximately 5 liters of beverage, although obviously the volume may vary within the scope of the present invention. 
       FIG. 1  provides a general view of a keg assembly  10  according to an embodiment of the present invention. The keg assembly  10  comprises an outer shell  12 , and a bag  14  within the outer shell  12  which provides a collapsible container for beer. A sealed cavity  15  is defined between the outer shell  12  and the bag  14 . The keg assembly  10  further comprises a cap assembly  30  having a beverage valve  18 , a gas valve  20  and a relief valve  22 . The outer shell  12  may be formed of common polyethylene teraphthalate (PET), and the bag  14  may be a simple plastic bag (e.g. commercial drinking water cask bladder). 
     The beverage valve  18  allows the beverage to exit the bag  14  to a beverage tube or conduit  24 , which is connected to a tap for dispensing the beverage. The beverage valve  18  is depressed upon connection of the beverage outlet  24 , which opens the valve  18  and allows the beverage to flow to the tap. Upon removal of the beverage tube  24 , the beverage valve  18  reseals (i.e. the bag  14  is connected to the tube  24  via a self-sealing coupling). In this embodiment, the beverage valve  18  allows but does not control the beverage flow—it functions mainly to retain internal pressure whilst the keg assembly  10  is in storage, and to automatically connect or reseal the keg  10  when the keg  10  is transferred to or from the dispensing system. 
     Furthermore, in this embodiment, there is a dip tube  28  within the bag  14 , which helps ensure that all of the beverage within the bag  14  can be dispensed. As the beverage is dispensed and the bag  14  collapses, the dip tube forms a non-blocking channel from the bottom of the bag  14 . The dip tube  28  helps prevent the neck of the bag  14  from pinching off, which would otherwise prevent the beverage reaching the beverage outlet as the bag  14  collapses. 
     The gas valve  20  is connected to a gas tube  26 , which is in turn connected to a gas compressor. During operation, the compressor maintains the pressure within the sealed cavity  15  above the external atmospheric pressure. The compressor is triggered by a pressure activating switch—as the pressure within the cavity  15  is decreased (e.g. by a decrease in volume of the bag  14  as the beverage is dispensed), the compressor forces gas through the gas tube  26  and gas valve  20 , into the cavity  15 . Whilst the tap is open, this effectively squeezes the bag  14 , which collapses, and beer is accordingly forced out through the beverage valve  18 , to the tap via the beverage tube  24 . 
     The relief valve  22  is provided in order to allow pressure to be relieved to atmosphere in the event of excessive pressure build-up within the bag  15 . This may occur occasionally with some carbonated beverages, and it can be a particular problem with beer brewed by home brewers, who may over-gas their beer. 
       FIGS. 2 to 7  show in more detail a particular embodiment of a keg assembly  10  according to the present invention.  FIG. 2  is a general overview image of the keg assembly  10 , with a cap assembly  30  and a dip tube  28  shown through a transparent view of the outer shell  12 . 
       FIG. 3  shows the components of the cap assembly  30  in more detail. The cap assembly  30  in this embodiment comprises five components. Although these components will be described below, the shape and function of the components is probably best seen from the figures, and in particular  FIG. 3 . 
     The first component  32  and second component  34  are shown together in  FIG. 4 .  FIGS. 5 ,  6  and  7  respectively depict the third component  36 , fourth component  38 , and fifth component  40  of the cap assembly  30 . O-rings  50  are used to ensure sealing connection between each of the cap components. A clamping arrangement (not shown) may be used to secure the cap assembly  30  together, and to secure it to the outer shell  12  of the keg assembly  10 . 
     The first component  32  is fitted into an opening at the top of the outer shell  12 . It has two apertures—a large aperture for providing a conduit into the bag  14 , and a smaller aperture for providing a conduit into the cavity  15 . The second component  34  is located at the bottom of the large aperture of the first component  32 , and provides a nozzle for connection to the bag  14 . These components are shown fitted together in  FIG. 4 . 
     In some embodiments, the second cap component  34  may be non-removably connected to the bag  14 —it may simply provide a connecting component to connect the bag  14  to the cap assembly  30 . It provides a relatively convenient method of allowing the bag  14  to be connected to the cap assembly  30 . A user can simply push the second cap component onto the first cap component. Due to the moulded shape of the components  32 ,  34  which are designed to fit tightly together, and the presence of the O-rings  50 , the user can be confident that the connection between the bag  14  and the cap assembly will be sealed. 
     A third cap component  36  is also provided, shown separately in  FIG. 5 . This component  36  locates within and on top of the first cap component  32 . Three apertures are provided within this third component  36 . There is a small aperture which connects to the small aperture of the first component  32 , and allows the gas valve  20  to be fitted within it. This small aperture is located within but distinct from a second aperture, which is connected to the large aperture of the first component  32 . This second aperture provides a conduit from the bag  14  to the relief valve  22 . A third aperture is also connected to the large aperture of the first component  32 , and provides an outlet for the beverage from the bag  14 . A beverage valve  18  is located within this aperture. A helical channel  37  runs around the outside of the third component, and this defines the passage of the beverage to the beverage outlet and beverage valve  18 . 
       FIG. 6  depicts the fourth cap component  38 , which functions as a dip tube holder, and fits within the third cap component  36 . It also comprises a helical channel  39 , which runs around the outside of the fourth component  38 . The dip tube holder  38  includes a small central aperture for beverage to exit from the dip tube  28 , and a side aperture providing a conduit directly from the bag  14 , independent of the dip tube  28 . 
     The operation of the third and fourth components can best be seen from FIG.  3 —the beverage is drawn through the dip tube  28  to the top of the dip tube holder  38 . It then passes down the helical channel  39  of the dip tube holder  38 , and back up the helical channel  37  of the third cap component  36  to the beverage valve  18 . The helical channels  37 ,  39  restrict the flow rate during pouring, and they can be adjusted in different embodiments to suit the desired pour rate. Different cap components (i.e. different fittings) having different numbers of coils in their helical channel may be provided, for use with different beverages. 
     Gas pressure build-up within the bag  14  can be released directly through the relief valve  22  without passing through the dip tube  28 . 
       FIG. 7  depicts the fifth component  40  of the cap assembly  30 , which is placed on top of the third component  36 . It provides flanges for connection of a beverage tube  24  and a gas tube  26 , allowing exit of the beverage through the beverage valve  18  and entry of gas through the gas valve, respectively. It also comprises the relief valve  22 , which allows the release of gas to relieve pressure within the bag  14 . The relief valve  22  is provided to protect against rupture of the bag  14  caused by the evolution of fermenting gases attempting to overinflate the bag  14  within the outer shell  12 . It is a non-return valve which prevents the flow of compressed air into the bag  14 , particularly when the beverage is being dispensed. 
     Each of the valves  18 ,  20 ,  22  as shown in the figures, comprises silicon rubber plugs, which are retained and seated using helical springs. 
     During operation, the keg assembly  10  can be connected to a dispensing device, for chilling and dispensing the beverage. The dispensing device may have an internal cavity for receiving the keg assembly  10 —the rigidity of the outer shell  12  helps ensure that the keg assembly has a known shape, which allows it to be readily inserted into the dispensing device. 
     The dispensing device also provides a tap having a tap handle and a tap faucet, and a gas compressor. The beverage tube  24  connects the beverage valve  18  to the tap faucet, and the gas tube  26  connects the gas compressor to the gas valve  20 . 
     When the beverage tube  24  is attached, this depresses the beverage valve  18 , allowing beer to flow through the beverage valve. The gas compressor maintains the pressure in the sealed cavity, to a pressure above the external atmospheric pressure. Upon operation of the tap handle, the beverage flows from the bag and is dispensed through the tap faucet. This reduces the volume of the bag  14 , which accordingly decreases the pressure in the cavity. A pressure activating switch then triggers the compressor, and gas (typically air) from the compressor is forced through the gas tube  26  to the gas valve  20 , into the cavity  15 . This maintains the pressure within the cavity  15  and (at least whilst the tap is open) continues to collapse the bag  14 . In this way, the beverage is squeezed out of the bag  14 , through the beverage valve  18 , to the tap faucet. 
     To refill the keg assembly  10  when empty, the cap assembly  30  can be removed from the outer shell  12 . The beverage tube  24  and gas tube  26  may be disconnected from either or both of the cap assembly  30  and the dispenser. Then, the bag  14  can simply be removed and discarded. 
     Of course, in embodiments where the bag  14  is non-removably connected to the second cap component  34 , this component  34  may also be discarded. A new bag  14  and connecting component  34  can then be attached to the first cap component  32 . 
     The next step in the refilling process is to insert the first  32  and second  34  cap components can into the outer shell  12 , as shown in  FIG. 4 . The other components are not inserted (they remain removed from the cap assembly  30 ), which means that the large aperture in the first component  32  provides a beverage inlet of relatively large diameter for quick and easy filling. The new bag  14  can then be filled whilst located within the outer shell  12 . An auto cut-off function may be provided when filling, so a home-brewer can start the filling process, walk away, and the flow stops once the bag is full with 5 liters of beer. 
     Once the new bag  14  is full, the third  36 , fourth  38  and fifth  40  cap components can be sealingly connected on top of the first  32  and second  34  components, using any suitable connection or clamping arrangement. If required, the dip tube  28 , beverage tube  24  and gas tube  26  can then be re-connected, although disconnection of these components may not be required to refill the keg assembly  10 . However, it should be noted that generally the bag will be filled with a flat beverage (e.g. a beer brew being fermented by a home brewer), which must go through a secondary fermentation. As such, it will not usually be filled and attached to the dispenser for immediate dispensing—the keg assembly  10  will usually be placed in storage for some time before the beverage is dispensed. 
     As previously mentioned, the outer shell  12  provides a rigid exterior to the keg assembly  10 , having a known shape. This assists in connecting the keg assembly  10  to and within the dispensing device, and may also allow for easier stacking of multiple keg assemblies  10 . 
     Although an embodiment of the present invention has been described in the foregoing detailed description, it will be understood that the invention is not limited to the embodiment disclosed, but is capable of numerous rearrangements, modifications and substitutions without departing from the scope of the invention. Modifications and variations such as would be apparent to a skilled addressee are deemed within the scope of the present invention. 
     For example, in some embodiments the beverage could be dispensed from the bottom of the keg—in this case, the beverage valve may be located at the bottom of the bag, along with the other connections for connecting the bag within the outer shell and dispensing the beverage. This may reduce the need for a dip tube. However, it should be noted that in such an embodiment, there may be additional issues caused by sediment in the beverage. Furthermore, a pressure relief valve will still preferably be located at the top of the bag, and accordingly the bag may be more complicated with separate outlets at the bottom and top of the bag for the beverage and for excess gas, respectively. 
     It should also be noted that the keg assembly of the present invention could also be useful for artificially carbonating the beverage. The dispensing unit is already adapted to chill the beverage, so it is ready to take on carbon dioxide. Accordingly, gas may be forced through the beverage valve into the bag. The dip tube is well suited to take the carbon dioxide initially to the bottom of the bag, which facilitates its circulation within the beverage. 
     Throughout this specification and the claims that follow unless the context requires otherwise, the words ‘comprise’ and ‘include’ and variations such as ‘comprising’ and ‘including’ will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers. 
     The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that such prior art forms part of the common general knowledge.