Abstract:
A container for dispensing fluid under pressure, the container have a top and a base with a floor raised above the base by a downwardly depending skirt, a high pressure canister being positioned under the floor of the container within the skirt and having a regulator which is adapted to extend through the floor and into the container, whereby the regulator causes release of gas from the high pressure canister when the internal pressure in the container falls below a predetermined level.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention relates to the dispensing of fluids and, in particular, relates to the dispensing of beer under pressure. 
       BACKGROUND OF THE INVENTION 
       [0002]    Beer drinkers are particularly fond of beer which is dispensed under pressure from a barrel. In commercial facilities, the beer is stored in large barrels and then dispensed under pressure from a beer tap. This is known as draught beer and is particularly popular the world over. 
         [0003]    Attempts have been made to provide smaller barrels for domestic use. These barrels can vary between 5 L and 100 L and are usually pressurised to ensure the beer is dispensed in the same manner as draught beer is dispensed in commercial establishments. 
         [0004]    A problem with the domestic style of barrel is encountered in ensuring the beer is dispensed consistently at the required pressure. There is a tendency for the beer to be over pressurised at first usage and, then as the pressure within the barrel drops, the beer becomes either flat or is difficult to dispense due to a loss of pressure. It has been proposed to place, within the beer barrel, boosters in the form of small, highly pressurised canisters that release a boost of gas, usually nitrogen or carbon dioxide, into the beer as the pressure within the barrel drops. It is these issues that have brought about the present invention. 
       SUMMARY OF THE INVENTION 
       [0005]    According to one aspect of the present invention there is provided a container for dispensing fluid under pressure, the container having a top and a base having a raised floor supported by a downwardly depending skirt, a dispensing tap located in the container, the floor of the container having an aperture, a high pressure canister being profiled to fit within the skirt under the floor of the container, the canister having projecting therefrom a regulator which is adapted to fit into the aperture with the regulator extending into the container, the regulator having a primer whereby in use when the container is filled with fluid and the interior of the container pressurised the regulator is primed so that as the pressure in the container drops as the fluid is dispensed the regulator activates a valve in the canister to release gas under pressure into the container to elevate the pressure within the container to maintain a substantially constant pressure. 
         [0006]    According to another aspect of the present invention there is provided a container for dispensing fluid under pressure, the container having a top and a base with a floor raised above the base by a downwardly depending skirt, a high pressure canister being positioned under the floor of the container within the skirt and having a regulator that is adapted to extend through the floor and into the container. 
         [0007]    According to one aspect of the present invention there is provided a method for preparing a container for dispensing of fluid under substantially constant pressure, comprising attaching a pressure control device to the underside of the exterior of the container, the pressure control device having a regulator adapted to extend through the floor of the container into the interior of the container, the regulator including a primer whereby the method comprises securing the pressure control device to the container, filling the container with fluid, pressurising the container to a pressure slightly above the operating pressure via the dispensing tap, the pressure control device either being subsequently pressurised to an excess pressure or being supplied pre-pressurised to the excess pressure. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0008]    An embodiment of the present invention will now be described by way of example only with reference to the accompanying drawings in which: 
           [0009]      FIG. 1  is a side elevational view of a container for dispensing beer; 
           [0010]      FIG. 2  is a cross sectional area taken on the lines AA of  FIG. 1 ; 
           [0011]      FIG. 3  is an enlarged view of the cross section of the base of the container illustrating a pressure booster and regulator primed for use; and 
           [0012]      FIG. 4  is an enlarged cross sectional view of the regulator when activated to release pressurised gas from the booster. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0013]    The beer barrel  10  illustrated in the accompanying drawings is constructed of metal to assume a cylindrical shape with a top  11  and base structure  12 . The actual floor  13  of the barrel  10  is raised above the base  12  of the barrel and is supported by an annular skirt  14  that defines a space  15  between the floor  13  of the barrel and the base of the skirt  14 . 
         [0014]    This space  15  is utilised to house a canister  20  which can be pressurised with gas, usually a mixture of nitrogen and carbon dioxide, to pressures in excess of 500 psi. The canister  20  is toroidal in shape and is designed to fit within the space defined by the skirt at the base of the barrel. As shown in  FIG. 3 , the toroidal canister has inwardly dished top and bottom walls  21  and  22  and has a central aperture  23  that supports a plug  30  that has a central throughway  31 , an enlarged upper flange  32  that is welded to the upper surface of the top wall  21  of the canister  20  and a lower flange  33  which projects past the bottom wall  22  of the canister  20  to terminate approximately level with the base  12  of the barrel  10 . 
         [0015]    The throughway  31  is stepped to define a wide opening  36 , a threaded portion  37  and an unthreaded passage  35 . The opening  36  is closed by a removable end cap  39 . A valve body  40  is screwed into the threaded passageway  37  and located in a sealed engagement with the plug  30  via an O-ring  41 . The valve body  40  has a one-way valve including a valve member  42  located by a retainer  43  against a coil spring (not shown). The end  45  of the valve member  42  projects into a conical space  43  defined within the valve body  40  and the valve member  42  includes a head  47  which seats against an internal bore  48  of the valve member via an O-ring  49 . The one-way valve is used to pressurise the canister  20  and the plug  30  has at least one aperture  46  that communicates with the interior of the canister. 
         [0016]    The floor  13  of the beer barrel  10  has a centrally positioned aperture  16  and a circular mounting boss  17  with a central partially threaded aperture  18  is welded to the interior of the floor  13  of the barrel to extend across the aperture  16 . 
         [0017]    The upper flange  32  of the plug  30  has an upwardly and outwardly projecting spigot  38  which is externally threaded to screw into the boss  17  welded to the floor  13  of the barrel  10 . The spigot  38  in turn has an internally threaded aperture  39  that accommodates a screw threaded spigot  51  formed on the end of a second plug  60  that forms the base of the regulator  50  which extends into the barrel as shown in  FIG. 2 . 
         [0018]    In this manner, the centrally located plug  30  welded to the canister  20  is screw threaded through the floor  13  of the beer barrel in the boss  17  with the regulator  50  extending into the interior of the beer barrel. This allows the canister  20  to be protected by the downwardly depending skirt  14  on the beer barrel  10  and the regulator  50  to be firmly located within the base of the beer barrel to communicate with the interior of the beer barrel so that, when activated, the high pressure within the canister  20  can be released into the beer barrel. 
         [0019]    In use, the barrel  10  can be inverted and filled with beer through the aperture  16  in the floor  13  of the barrel  10  and then the canister  20  and regulator  50  are screwed into the floor  13  of the barrel. Alternatively, the canister  20  and regulator  50  can be screwed into the floor  13  of the barrel  10  and then the barrel is filled with beer from a dispensing tap (not shown) at the top  11  of the barrel  10 . The canister  20  can be pressurised to the desired pressure of approximately 500 psi either prior to delivery or can be pressurised through the one-way valve  40  after being positioned in the base of the barrel  10 . 
         [0020]    Once the barrel  10  is full of beer, it is then pressurised via the dispensing tap to a pressure of approximately 20 psi. 
         [0021]    The regulator  50  is of the kind disclosed in U.S. Pat. No. 7,021,559, the disclosure of which is incorporated herein by reference. 
         [0022]    The regulator  50  essentially comprises a one-way valve housed in the second plug  60 . A cap  70  is secured to the plug and includes two pressure chambers  71 ,  72  and a piston  73 . A primer  80  in the form of a syringe body  81  is secured to the top of the cap  70 . 
         [0023]    The second plug  60  has a central throughway  61  which locates a one-way valve  62  in the same manner as the one-way valve  40  in the base of the canister  20 . The one-way valve comprises a valve member  63  having a head  64  that seals against a valve seat  65 , a retainer  66  enclosing a coil spring (not shown) about the valve stem  67  and the end of the valve stem  67  is connected to the piston  73  which is axially slidable within a cylinder defined by a the interior of the cap  70  which is secured to the exterior of the plug  60  and sealed thereon by welding or adhesive. 
         [0024]    The cap  70  also includes a central hollow projection  74  defining a chamber  76  which houses a flexible chamber seal  75 . The space between the underside of the piston  73  and the one-way valve  62  is in communication with the interior of the barrel  10  and defines the first pressure chamber  71  and the space between the other side of the piston  73  and the cup seal  75  defines the second pressure chamber  72  or expandable chamber. Projecting axially from the top of the second chamber  72  is the syringe body  81  which includes a piston  82  with a downward projection  83  constituting the primer  80 . The chamber seal  75  is annular with a peripheral lip  77  supported by an annular rib  78  with the peripheral lip  77  and annular rib  78  bearing against the wall of the chamber  76 . The expandable chamber  72  is on one side of the chamber seal  75 . 
         [0025]    When the barrel  10  is pressurised, the piston  82  in the syringe body  81  is forced down to force gas past the chamber seal  75  into the second chamber  72 . The design of the chamber seal  75  is such that the pressure within the second chamber  72  on one side of the piston  73  is about 3 psi less than the pressure in the first chamber  71  on the other side of the piston  73  which equates to the internal pressure of the barrel  10 . As the contents of the barrel are released and the internal pressure drops, eventually the pressure in the first chamber  71  (about 17 psi) becomes greater than the internal pressure of the barrel  10  causing the piston  73  to be displaced downwardly to open the one-way valve  62  which causes release of the high pressure gas within the canister  20  to recharge the barrel  10 . In this way, the syringe piston  82  primes the cup seal  75  for use at start up to be operable once the barrel has been charged. As the pressure in the barrel  10  drops below 17 psi, the one-way valve is activated causing the barrel to be recharged from the high pressure gas contained in the canister  20  in the base of the barrel. 
         [0026]    An important design consideration with the barrel described above is its potential for reuse. The barrel, the pressurised canister and the plug which screws into the base of the barrel are all reusable. The only disposable and redundant component is the regulator and primer.