Patent GB-200882-A (GB)
Title: Improvements in or relating to refrigerating machines
IPC: F25C1/16
Filed: 1922-04-13
Abstract: 200,882. Stewart, W. April 13, 1022. Addition to 185,607. Ice-making, can or mould systems for; liquids frozen by evaporation in part; spray, freezing. - In apparatus wherein liquid to be frozen is sprayed upwardly into open conical moulds or cells cooled externally and subjected to the action of an exhauster, as described in the parent Specification, the cells are formed with hollow walls within which volatile refrigerant such as carbonic acid or ammonia is directly evaporated, the refrigerant being afterwards circulated through coils adapted to condense and congeal vapour arising from the spray. The cells may be located in a casing adapted to be exhausted by a steam-ejector, and the spraying-nozzles and water-supply chamber are carried by a platform adapted to be lowered from the bottom of the casing to enable the ice blocks to be removed, as described in the parent Specification. The cells preferably comprise upper and lower header pipes 40, 36, connected by pipes 41, Fig. 3, spaced apart by plates 42 welded thereto. The pipes 40, 36 are each composed of straight lengths bevelled at their ends and welded together to form a square, and the connecting pipes 41 are bent at their lower ends into the plane of the lower pipe 36. The liquefied refrigerant passes through an inlet pipe 46 and expansion valve 47 to a pipe 45 leading to the pipe 36, rises through the, connecting tubes 41 to the upper pipe 40 and flows thence through a coil 56 serving to congeal the vapour. The upper end of this coil is connected by a branch 57 to a chamber 51, from which any unevaporated refrigerant is returned through a pipe 50 to the supply pipe 45, while the evaporated refrigerant passes to a chamber 54 and thence to the compressor suction. The cell is supported on cross bars of the casing 1. This casing may comprise two annular sections connected by flanges 6. 7, and is supported by brackets 23 on pillars 24, which also serve as guides for the movable bottom of the casing. This bottom comprises a water supply reservoir with a perforated top 8<a> through which surplus spray returns to the reservoir, and spaced bottom plates 10, 20 providing a heat-insulated wall. This wall and a partial jacket 13 around the bottom edge of the fixed casing are connected by pipes 93, 94 with a pipe 91 communicating with the interior of the casing, and a partial vacuum is produced therein by the action of the steam-ejector 80 that serves to exhaust the casing and to cool the spray by evaporation. The spraying-nozzle 60, fitted with a regulating-valve and a feeling-rod for the ice block, as described in the parent Specification, is supplied by a motor-driven pump 66. By an arrangement of valves the supply to the nozzle 60 may be stopped and the pump may deliver liquid through nozzles 95 over the coil 56 to thaw-off congealed matter, which returns to the supply chamber. The joint between the movable bottom and the casing is similar to that described in the prior Specification. The bottom is supported in its raised position by counterweights 27 and is guided on the pillars by means of plates 25. A modified form of cell is described wherein the header pipes are each formed of two U- shaped pipes welded together. The parts of the lower pipe communicate with one another to form a single passage, while the upper pipe is divided by the joints into separate chambers. In this arrangement the refrigerant is admitted to one part of the upper pipe flows down one set of connecting pipes to the bottom pipe, and rises through the other connecting pipes to the other part of the top pipe. The ice-block is detached from the cell walls by raising the pressure of the refrigerant in the pipes, whereby they are slightly warmed and expanded.