GB652777A - Improvements in and relating to the control of refrigerating systems - Google Patents

Abstract

652,777. Refrigerating. BRITISH THOMSON-HOUSTON CO., Ltd. Aug. 5, 1948, No. 20742. Convention date, Aug. 5, 1947. [Class .29] In a refrigerating system comprising a low temperature evaporator 8 for cooling a chamber 5 and a higher temperature evaporator 9 cooling the insulated walls 4, liquid refrigerant being supplied to the evaporators by a compressing-condensing unit 10 through thermostatically-controlled valves 20, 22, refrigerant is supplied to the evaporator 8 only when the walls 4 have been cooled to a predetermined low temperature. When the walls 4 reach this low temperature a bulb 25 in the plane of evaporator 9 opens a valve 24 to admit refrigerant to evaporator 8 and a bulb 27 closes a valve 26 to shut off refrigerant supply to evaporator 9. The compressor motor may be controlled in accordance with the temperature in the chamber 5. In a modification, Fig. 3, the evaporators 8, 9 are connected to condensing units 28, 29 respectively, the power supply to the compressors of which is controlled by switches 46, 43 operated by thermostatic bulbs 48, 45 similarly located to the bulbs 25, 27. The main supply to the system incorporates a switch 39 operated in accordance with the temperature of the chamber 5. The bulbs 48, 45 may alternatively control valves in the refrigerant supply pipes 18, 19. Back pressure valves may be fitted to the condensing units 28, 29. The chamber and walls may be cooled by brine systems or secondary systems cooled by the primary system. Specification 20741/48 (as open to inspection under Sect. 91) is referred to.