Abstract:
A beer keg includes a container having a base and a wall extending upward from a periphery of the base. A liner within the container includes a base, sidewalls and a mouth. The base of the liner interlocks with the base of the container to prevent relative rotation therebetween. A valve is disposed over the mouth of the liner.

Description:
[0001]    This application claims priority to U.S. Provisional Application Ser. No. 61/170,972, filed Apr. 20, 2009. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The present invention relates generally to large multiple serving beverage containers, in particular, beer kegs. 
         [0003]    Metal beer kegs primarily made of stainless steel have been the preferred method of transporting draft beer from the brewery to the retailer (i.e. restaurant, bar, store) for many years. They come in several sizes, between a sixth barrel and a half barrel. 
         [0004]    Metal kegs are very durable and can give many years of service. However, they have a high initial purchase price and several additional costs during use. First, shipping an empty keg back to the brewery increases the actual cost of using stainless steel or metal beer kegs. Next, the keg must be prepared for refilling, including being emptied, inspected, pressure checked, precleaned with water, cleaned with a caustic rinse, steam sterilized and evacuated with CO 2  before it can be refilled. Damaged kegs must also be repaired as needed at this time. 
         [0005]    The high cost of stainless steel has made it profitable for thieves to steal empty kegs and sell them for scrap. The cost of lost or stolen kegs further increases the cost of using metal beer kegs. 
       SUMMARY 
       [0006]    A beer keg includes a container having a base and a wall extending upward from a periphery of the base. A liner within the container includes a base, sidewalls and a mouth. The base of the liner interlocks with the base of the container to prevent relative rotation therebetween. A valve is disposed over the mouth of the liner. 
         [0007]    According to a method according to another aspect of the invention, the liner is pressurized with a gas before being filled with the liquid (beer). This internal pressure provides increased strength to the liner. The internal pressure may also assist in retaining the liner within the container, especially when inverted. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a side view of a beer keg according to one embodiment of the present invention. 
           [0009]      FIG. 2  is a perspective view of the beer keg of  FIG. 1 , with half broken away. 
           [0010]      FIG. 3  is a side section view of the beer keg of  FIG. 1 . 
           [0011]      FIG. 4  is an enlarged view of the upper portion of  FIG. 3 , showing the top of the liner in both the expanded and unexpanded positions. 
           [0012]      FIG. 5  is a side view of the keg of  FIG. 4 . 
           [0013]      FIG. 6  is an enlarged view of the bottom portion of the container. 
           [0014]      FIG. 7  a perspective view of the underside of the container of  FIG. 1 , with half broken away. 
           [0015]      FIG. 8  is a section view of the liner and container of  FIG. 1  being filled under pressure. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0016]      FIG. 1  illustrates a plastic one-way beer keg  10  according to one embodiment of the present invention. The plastic beer keg  10  includes an outer container  12  having a removable lid  14 . The outer container  12  has an outer wall  16  extending upward from a periphery of a base  18 . The plastic beer keg  10  is symmetric, such that the side not in view of  FIG. 1  is symmetric to that of  FIG. 1 . 
         [0017]    The wall  16  includes a pair of handle openings  20  extending through an upper portion of the outer wall  16 . An annular rib  26  extends outward from the outer wall  16  above the handle openings  20  to increase the rigidity of the container mouth. An annular skirt  28  extends outward from the outer wall  16  below the handles  20  to increase the rigidity of the outer wall  16  and to provide additional grip points. 
         [0018]    It should be noted that the container  12  is generally in the form of a pail, which provides several advantages as will be described below. It should be noted that, in general, the familiar form factor of the pail with removable lid provides many of the advantages of the present invention beer keg  10 , including nestability of the containers  12  with one another, ease of carrying, removability and replacability of the lid  14 , and reusability of the container  12  and lid  14 . This also provides advantages to the extent that there are existing technologies for the manufacture, labeling and handling of pails generally. The container  12  and lid  14  may be HDPE, polypropylene or other suitable materials. 
         [0019]      FIGS. 2 and 3  illustrate the beer keg  10  of  FIG. 1  partially broken away. A liner  40  (or “bottle”) has an outer wall  42 , which generally matches the shape of the interior of the container  12 . The liner  40  may be blow-molded PET or other suitable material. As is known with PET beverage bottles, the liner  40  is provided with a base having a plurality of feet  44 , to make the liner stable for stacking, shipping and conveying. The mouth  46  of the liner  40  is aligned with an opening  30  through the lid  14 . The feet  44  of the liner  40  rest on the base wall  18  of the container  12 . The base  18  of the container  12  includes corrugations  32  that interlock with the feet  44  of the liner  40 . The lid  14  is shown as having a snap-on fit with the outer container  12 , but a threaded attachment between the lid  14  and the outer wall  16  could also be used. The lid  14  has an outer annular wall  36  or lip  36  that is radially outward of the upper edge  36  of the container  12 . 
         [0020]    A valve/spear assembly  50  is secured to the mouth  46  of the PET bottle  40 . The valve/spear assembly  50  includes a spear  52  extending downwardly to the bottom of the liner  40  from a valve  54  at the liner  40  mouth  46 . The valve  54  and spear  52  are not shown in detail. 
         [0021]    In  FIGS. 4 and 5 , the right side of the drawing shows the liner  40  in its initial state in the outer container  12 , while the left side of the drawing shows the liner  40  in its pressurized state after being filled with a carbonated beverage. As shown, the liner  40  expands when pressurized. The lid  14  is angled downwardly to the opening around the valve  54 . The opening  30  in the lid  14  permits the liner  40  to expand without the liner  40  contacting the lid  14 . At either height, the valve  54  is below the height of the outer wall  16  of the outer container  12  to protect the valve  54  and above the height of the lid  14  to keep the valve  54  in the proper location. There is also sufficient room to place a removable cap (not shown) over the valve  54 . 
         [0022]    Referring to  FIG. 5 , the lid  14  includes an annular outer portion  62  over the upper edge  34  of the wall  16  of the container  12  and an annular inner portion  64  within the annular outer portion  62 . The annular inner portion  64  is offset downwardly from the annular outer portion  62 . The opening  30  is formed through the annular inner portion  64 . The lid  14  also includes an annular angled portion  66  extending between the annular outer portion  62  and the annular inner portion  64 . The lid  14  includes an annular inner wall  68  adjacent an interior surface of the wall  16  of the container  12 . A plurality of radial ribs  70  on a lower surface of the lid  14  connect the annular inner wall  68  to the annular angled portion  66 . 
         [0023]    In  FIGS. 6 and 7 , it is shown that the feet  44  interlock with the corrugations  32  in the bottom wall  18  of the outer container  12 . This prevents relative rotation between the liner  40  and the outer container  12  during tapping of the keg  10 . 
         [0024]      FIG. 8  illustrates one method for filling the keg  10 . The keg  10  is filled in the inverted orientation as shown. The liner  40 , after being formed, it pressurized with CO 2  (or other suitable fluid) before or after being inserted in the outer container  12 . This expands the liner  40  sufficiently that the liner  40  bears against the outer wall  16 . The lid  14  is secured to the mouth of the outer container  12 . The pressure in the liner  40  is sufficient to hold the liner  40  inside the outer container  12  when inverted. The empty inverted keg  10  is placed on rails  58 . The filling valve  60  rises to engage the valve  54 , while an upper clamp  62  bears down on the bottom wall  18  of the outer container  12 . If the liner  40  does slide down when inverted, the filling valve  60  lifts it up against the bottom wall  18 . The pressure inside the liner  40  also assists the liner  40  to withstand the clamping force between the upper clamp  62  and the filling valve  60 . Optionally, the neck of the liner  40  could be corrugated to increase strength. 
         [0025]    The liner  40  is then filled by the filling valve  60 . The filling valve  60  then lowers again. The liner  40  when full is pressurized and expanded against the outer wall  16  of the outer container  12 . The friction between the liner  40  and outer wall  16  holds the liner  40  in the outer container  12  even when the liner  40  is full. Optionally, portions of the outer wall  16  could be made with a smaller inner diameter to increase the friction between the liner  40  and outer wall  16  after the liner  40  is pressurized. The filled keg  10  is then turned back to the upright position for shipping, sale and use. 
         [0026]    Prior to filling, and after removal of an empty liner  40  by the user, empty containers  12  can be nested within one another, thus reducing their overall stacking height. Further, the lids  14  are also stackable and partially nestable. The used liners  40  and valve/spear assemblies  50  can be recycled. The empty outer containers  12  can be returned to be used with new liners  40 , or recycled. The empty outer containers  12  can also be reused for other purposes. 
         [0027]    In accordance with the provisions of the patent statutes and jurisprudence, exemplary configurations described above are considered to represent a preferred embodiment of the invention. However, it should be noted that the invention can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope. Alphanumeric identifiers on method claim steps are for ease of reference in dependent claims and do not signify a required sequence unless otherwise specified.