GB767050A - Improvements in refrigeration apparatus - Google Patents

Abstract

767,050. Refrigerating. GENERAL MOTORS, Ltd. July 28,1955 [Aug. 5, 1954], No. 22813/54. Class 29 Compression refrigeration apparatus includes a tubular evaporator 6 with part 7 of the tube between the inlets of the compressor 1 and evaporator coiled to form the secondary winding of a transformer 9 adapted to induce a defrosting current in the evaporator, the circuit being completed by a low resistance electrical connection 10, preferably a heavy stranded copper cable or a copper strip, clamped or soldered between the inlet of the evaporator and the end of the coiled part 7 of the tube nearest the compressor. The evaporator is coiled or formed into a grid with the individual coils not in electrical contact, while the coiled part 7 is preferably at the outlet end and at the bottom of the evaporator. A thermostatic expansion valve 5 is situated at the inlet of the evaporator between the connection 10 and close to it and the compressor 1 and is controlled by a bulb 12 placed at the outlet of the evaporator also between the compressor and connection. The transformer is designed to give a relatively large current through the secondary coil at low voltage with a resultant heating of the evaporator. The defrost cycle may be initiated by predetermined intervals of time, number of compressor cycles or periods of operation of the compressor, or may be manually controlled.