GB786369A - Improvements in and relating to refrigeration systems - Google Patents

Abstract

786,369. Refrigerating. PRESSED STEEL CO., Ltd. Nov. 23, 1955, No. 33543/55. Class 29 In a compression refrigeration system defrosted by the "hotgas method, the refrigerant vapour is heated by water at atmospheric pressure, which is itself heated by electrical or other means. In a first embodiment, Fig. 1, the hot gas line 19 leads from the outlet of the compressor 10, is in heat exchange with a liquid trap in the suction line 17, has a coil 22 immersed in a water tank 23 and is in heat exchange with a defrost water drain 25 and drip tray 24 before connecting with the evaporator 16. A valve 20 in the line 19 is opened'to initiate defrosting. The water tank 23 is open to atmosphere, losses due to evaporation being recovered from defrost water draining into the tank, and the water is heated by an immersion heater 28, which may be energized continuously, subject to the control of a thermostat 29 operated in response to the temperature of the water. In a second embodiment, Fig. 2, the hot gas line is not put in heat exchange with the water tank 23 which is instead utilized to evaporate any liquid refrigerant entering the suction line 17 to the compressor during defrosting. Entrance of refrigerant to a by-pass pipe 32 in the suction line is controlled by a valve 31 opened with valve 20 on initiation of defrosting, the by-pass leading to the coil 22 immersed in the tank 23 and back to the suction line. Means are provided by which the water in the tank is prevented from exceeding a fixed level, thus keeping the pressure atmospheric. Specification 764,736 is referred to.