Patent Publication Number: US-6666358-B1

Title: Beer container

Description:
TECHNICAL FIELD 
     This invention relates to beer containers and particularly to containers for rapidly dispensing beer in commercial establishments or at sporting and social events. 
     BACKGROUND OF THE INVENTION 
     Beer is presently supplied to commercial establishments or for special events in stainless steel kegs. These are of sturdy welded stainless steel construction and are fitted with a dispensing spear structure comprising a long stainless steel dispenser tube through which to dispense beer from the bottom of the keg and a pressurising valve through which to supply pressurising CO 2  gas into the keg so as to pressurise the contents and force the beer out through the dispensing tube when a dispensing valve is operated. 
     Stainless steel beer kegs are very expensive to produce and they are designed to be returned to the brewery for cleaning and refilling. They will typically be the property of the brewery which may accordingly need to have large sums of capital committed to maintaining appropriate stocks of kegs. Large sums can be lost if kegs are not returned. This problem could be largely overcome if it were possible to supply beer in bulk in low cost disposable dispensing containers, but no satisfactory containers for this purpose have hitherto been available. 
     Plastics technology has been applied to the manufacture of disposable beverage containers in small sizes, such as soft drink and beer bottles. These have generally been blow moulded in PET (polyethylene terephthalate), but it has not been possible to apply this technology to the production of larger size dispensing containers because of the barrier properties of PET in large size containers and the problem of producing a construction which allows effective recycling of all of the materials required for the dispensing components of a workable container. The present invention overcomes these problems by providing a multi-component container in which all components may be fully recyclable. 
     DISCLOSURE OF THE INVENTION 
     According to the invention, there is provided a beer container comprising: 
     an inner hollow shell of blow moulded PET to hold beer; 
     an outer hollow shell of moulded high density polyethylene closing and supporting the inner shell; and 
     a spear structure including a dispenser tube extending from a bottom interior region of the inner shell through to a dispensing outlet at the top of the outer shell. 
     Preferably, the spear structure in fixed to the inner shell and is constructed of PET. 
     The spear structure may incorporate a valve for supply of pressurising CO 2  gas into the interior of the inner shell and a beer dispenser valve At the dispensing outlet, both valves being moulded in PET. 
     Preferably, the outer shell is formed in separable pieces which can be separated from the inner shell for recycling of the high density polyethylene of the outer shell separately from the PET material of the inner shell and the spear. 
     The outer shell may, for example, be comprised of a generally open topped tub-shaped body fitted with a releasable lid. The lid may be a snap fit on the tub shaped body. 
     Preferably, the inner shell is a sliding fit within the tub shaped main body of the outer shell, whereby it can be slid from the outer shell main body when the lid is removed. 
     The peripheral wall of the outer shell may be formed with a series of circumferentially spaced, inwardly projecting ribs to engage the inner shell at circumferentially spaced locations to provide the sliding fit of the inner shell within the outer shell. 
     Alternatively, the outer shell may have a plain cylindrical peripheral surface within which the outer shell is a neat sliding fit. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In order that the invention may be more fully explained, one particular embodiment will be described with reference to the accompanying drawings, in which: 
     FIG. 1 is a perspective view of a beer keg constructed in accordance with the invention; 
     FIG. 2 is a vertical cross section through the beer keg of FIG. 1; and 
     FIG. 3 is an enlarged detail of an upper part of a spear structure installed in the keg. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The illustrated beer keg comprises an inner hollow shell  11 , an outer hollow shell  12  enclosing and supporting the inner shell, and a spear structure denoted generally as  13 . Spear structure  13  comprises a dispenser tube  14  extending from an inlet opening  15  near the bottom of the inner shell  11  to a dispensing outlet  16  located at the top of the outer shell  12 . 
     Inner shell  11  serves as a receptacle to be filled with beer. It has a generally cylindrical mid-part  11 A, an upwardly domed upper-part  11 B, and a downwardly domed lower part  11 C which form a hollow container approximating a prolate spheroid. The inner shell also has a cylindrical neck part  11 D standing up from the domed upper part  11 B and surrounding an upper-part of the spear structure  13 . 
     Inner shell  11  is blow moulded from PET. In cases where short shelf life is not a problem, it may be moulded in a single layer of PET. In order to improve shelf life by limiting ingress of oxygen and egress of CO 2 , the shell  11  may be blow moulded with a multi layer or laminated construction as is known in the production of PET bottles, or alternatively, it may be lined internally with an inert coating to serve as a barrier to permeation by oxygen and CO 2  or a barrier coating may be sprayed on and may be such that it can be washed to allow recycling of the PET material of the inner shell. Suitable barrier coatings for this purpose are disclosed in International Patent Application PCT/US95/01545 of PPG Industries Inc., published Oct. 12, 1995, under No. WO 95/26997, the disclosure of which is hereby incorporated by reference herein. 
     Spear structure  13  is formed of moulded PET components and it is fixed into the upper end of the inner shell  11  by heat swaging the neck part  11 D of the inner shell onto upper part of the spear structure so that the inner shell  11  and spear structure  13  form a unitary structure consisting essentially of PET, but optionally with a barrier coating which can be washed off before recycling of the PET material. 
     Outer shell  12  is formed of components, both moulded of high density polyethylene, namely an open topped tub shaped main body part  17  and an upper lid part  18  which is a press fit into the main body part. The peripheral wall of the main body part  17  is formed with two circumferential outstanding ribs  19  which aid in handling of the container with mechanical handling equipment. Indeed the outer shell or container may have the same external dimensions and features as conventional stainless steel kegs to enable the container to be generally handled and filled with the same equipment as the standard stainless steel kegs. 
     Inner shell  11  serves as a hollow beer container which is fitted within a hollow enclosure  21  formed by the tub shaped main body part  17  and lid part  18  of the outer shell  12 . The cylindrical mid-part  11 A of the inner shell is a sliding fit within the tub shaped main body part  17  of the outer shell. The lower end of the outer shell is shaped to form an upwardly dished floor  22  for the enclosure  21 , with a curvature to match the domed lower part  11 C of the inner shell thereby to provide secure and effective bottom support for the inner shell. The lower end of the outer shell is also shaped to form a peripheral base rim  20  disposed about the floor  22  and extending below the floor to flat base surfaces  20 A to provide a stable base on which the keg can be stood upright. 
     Upper lid part  18  is upwardly dished to receive the domed upper part  11 B of the inner shell, thereby to provide firm location of the upper part of that shell. Lid part  18  has a central opening  23  through which the tubular nick  11 D of the inner shell and the upper part of open structure  13  project for a short distance. Lid part  18  also has an outer peripheral flange  24  which is a press fit within the main body part  17  of the outer shell at a location below its upper end, the upper end of part  17  thus forming an upstanding peripheral skirt  24  of the outer shell  12  which extends around and protects the projecting upper part of the spear structure  13 . 
     The upper part of spear structure  13  includes a moulded PET valve body  25  which is fitted to the upper end of dispensing tube  14  and has a central tubular spigot  26  defining the dispensing opening  16 . Valve body  25  has an outer tubular barrel part  27  surrounding the spigot  26  and incorporating at its upper end an annular coupler  28  to couple the spear structure to a beer dispensing system as described below. The spear structure  13  is fixed to the inner shell  11  by heat swaging the tubular neck  11 D of the shell about the upper part of the outer barrel part  27  of the spear valve body  25 , an O-ring  29  being clinched between the valve body and the neck  11 D to form a gas tight seal to prevent escape of gas from the inner shell when it is pressurized. 
     A series of circumferentially spaced annular passages  31  are formed in valve body  25  between the central spigot  26  and outer barrel part  27  and the lower ends of these passages are closed by an annular sealing ring  32  snap fitted into a circumferential recess in the lower part of valve body  25  to serve as a one way valve for flow of CO 2  gas downwardly into the inner shell through the passages  31 . A spool valve  33  fitted with an O-ring seal  34  is located within the central spigot  26  of valve body  25  to close the dispensing opening  16  unless depressed downwardly against the internal gas pressure, 
     Pressuring CO 2  is applied to the interior of the inner shell  11  through the valve passages  31  and outer valve  32  which acts as a one-way valve to hold the pressure within the container, the spool valve acting under the internal pressure to close off the dispensing opening  16 . To dispense beer from the pressurised container a conventional dispenser is coupled to the upper end of the spear structure by means of the coupler  28 , the dispenser incorporating a mechanically operable plunger to depress the inner valve spool  33  to allow beer to flow through the dispensing opening  16  into the dispenser. 
     When inner shell  11  is charged with beer and is pressurised, it is expanded firmly against the outer shell  17  so as to be firmly located and supported. When the container has been emptied of beer, the lid  18  of outer shell  12  can be readily removed to allow the inner shell  11  (and with it the spear structure  13 ) to be removed from the main body part  17  of the outer shell. The unpressurised inner shell  11  is a sliding fit within the outer shell and it is readily removable. The two parts of the outer shell can be directed to a recycling plant for recycling of high density polyethylene material. The inner shell  11  and spear structure  13  can be directed to a plant for recycling PET material, such plant including a wash to wash out any gas barrier coating applied to the inner shell. 
     The illustrated beer keg construction can be produced quite economically as a fully disposable, low cost containers Moreover, it is fully recyclable since it can be readily separated into PET and high density polyethylene components which can be fed to existing recycling facilities for those particular materials. However, the illustrated keg has been advanced by way of example only and the invention is not limited to the details of that construction. Containers according to the invention may be produced in a variety of sizes and the constructional details may vary according to the particular size of the container. For some sizes, for example, the main body part of the outer shell may be formed with circumferentially spaced reinforcing ribs projecting inwardly of the shell and providing circumferentially spaced supports for the inner shell rather than continuous support about the periphery of the inner shell. The spear construction could also be varied considerably for differing size containers. It is accordingly to be understood that the invention is no way limited to the constructional details of the illustrated beer keg and that many modifications and variations will fall within the scope of the appended claims.