GB1331425A - Containers - Google Patents

Abstract

1331425 Containers for pressurized beverages METAL BOX CO Ltd 12 Oct 1970 [7 Aug 1969 25 Feb 1970] 39535/69 and 9073/70 Headings B8C and B8D [Also in Division B1] A container such as a can comprises a first chamber 15 or 77 for holding a liquid such as beer under pressure, a second chamber 14 or 76 for holding a gas such as CO 2 or CO 2 /N 2 under pressure, and a dividing wall 12 or 71 having at least one through slit 16 or 78 which is normally held closed by the resiliency of the material but which opens due to the pressure difference thereacross when the first chamber 15 or 77 is opened. The second chamber is situated at the can bottom below the beer so that when the can is opened gas passes through the slit(s) into the beer to assist in the formation of the beer head. The slit may be formed in the membrane 17A of a rubber or plastics valve bung 17 inserted in a chamber-dividing wall 12 (40, Fig. 4) or may comprise an integral part such as the disc 73 or portion 72 of a frusto-conical dividing wall 71 made of a resilient thermoplastics material such as polypropylene or polyethylene. The gas may be introduced through an inlet comprising a hole 19 or crescent-shaped slit (50, Fig. 5) to pass between an internal inlet-covering resilient patch 20 and the can base 11. Alternatively, the gas may be introduced through a passage(s) which is located between a plug 81 and the can base 11 and which is formed either by plug flutes (83, Figs. 9, 10) or by a throughway in the can base located adjacent the plug hole periphery. The inlet may be closed by a solder or epoxy bead 21 which may be covered by a guard 60. The plug which has a countersunk head that may be topped by a cylindrical extension (91, Fig. 11) may be rammed home by a plunger (88, Fig. 12). The can base (30, Fig. 4) and the dividing wall (40, Fig. 4) may have central recesses for siting the patch 20 and bung 17 respectively and the wall 12 (40, Fig. 4) may be provided with a circumferential bead or series of pips for facilitating stacking prior to can assembly. For the embodiment shown in Fig. 1 the can is filled by seaming the can base 11, wall 12 and body 10 together, charging the chamber 15 with beer, seaming on the can top, inverting the can and forcing gas through the inlet to pressurize the beer and chamber 14. For the embodiment shown in Fig. 8, the can is filled by seaming the can top to the body 10, inverting the can to fill the chamber 77 with beer, seaming on the wall 71 and base 70, partly inserting the plug 81 if not already positioned and pressurizing the beer and chamber 76 using a gassing head (87, Fig. 12) The latter comprises a valved gas inlet (89) which may pass through the plug plunger (88) or through the side or end of the gassing head.