GB1228776A - - Google Patents

Abstract

1,228,776. Dispensing measured quantities of liquids. E. R. PAXMAN, and M. G. BIRKETT. 20 Aug., 1968 [24 Aug., 1967], No. 38977/67. Heading B8N. In a free piston liquid, e.g. beer, dispensing apparatus, the piston 5 moves within a duct 4 which is connected directly to intermediate ports 8, 9 of a tap 10. The tap further includes and inlet port 11 connected to a liquid supply, an outlet port 12 and a valve member 10a movable between the illustrated first position in which the inlet port is connected to the intermediate port 8 and the other intermediate port 9 is connected to the outlet port and a second position in which the connections of the intermediate ports to the inlet and outlet ports are reversed. The piston is capable of sealing engagement with each of the intermediate ports. The piston may be a ball of rubber, plastics or metal and the duct may be of polyethylene, nylon, copper, steel or stainless steel. The liquid is preferably fed from a supply via a coil disposed in a refrigeration unit 1 to the inlet port, and the duet is also preferably within the unit. The duct, if remote from the unit, may be insulated in an insulated container, or it may be coaxial with and within a further duct with refrigerant gas being passed between the ducts. The tap 10 may be operated manually (as shown) pneumatically or electrically. A locking device 16 forced towards the valve member by liquid flowing through the inlet 11 engages with one or the other passage in the valve member to prevent operation of the tap during liquid flow. Disengagement of the locking device may be effected by the piston operating a switch or photo-electric cell. The piston when made of rubber or plastics may be filled with air, liquid, gas or sponge. Alternatively the piston may include a foam rubber body (19) with two rubber end seals (20, 21) (Fig. 4a, not shown), or a double ball (24) (Fig. 4c).