GB764810A - Plural temperature refrigerator - Google Patents

Abstract

764,810 Refrigerating. PHILCO CORPORATION. Feb. 23, 1955 [Feb. 23, 1954], No. 5460/55. Class 29 In a compression system, refrigerant flows through a pipe 16, Fig 1, from the condenser 15 to one vertical conduit 19 of a control device 18 whence it normally flows into another vertical conduit 20 having a first outlet 24, but, when heat is applied to the lower part of the first conduit, this flow is stopped by the resulting generation of vapour and the refrigerant rises to leave the first conduil through a second outlet 25. As shown in Fig. 1, refrigerant flows from first outlet 24 through a restrictor 26 to two evaporators 10, 11 in series and flows from the second outlet through a restrictor 27 to the second evaporator 11 only. The first conduit is heated by an electric element 34a energized upon the attainment of a predetermined low temperature by the first evaporator' 10. As shown in Fig. 4, the second conduit is in the form of an open ended tube 42 enclosed inside the first conduit 39, with inlet ports 40 and outlet ports 41, 45. Normal flow is in at 40 and then out by syphonic action at 45. When heater 46 operates a vapour blockage is set up at the lower end of conduct 39 and the refrigerant flows out by port 41. In a further modification (Fig. 3, not shown), the heater is replaced by a mass of material having a high thermal capacity, in contact with the ambient air. The compressor is controlled only by a thermostat in the food storage compartment operating between a temperature high enough to obtain complete defrosting of'evaporator 10, and a temperature somewhat higher than the minimum desired evaporator temperature. At the start of each compression period, the refrigerant is passed only to the low temperature evaporator, because of the vapour block in the first conduit caused by heat exchange between the mass and the refrigerant. By controlling the delay before normal conditions of flow prevail a fairly constant temperature can be maintained in the food storage compartment. The second outlet 25 may lead merely to a by-pass for the evaporator 10, evaporator 11 being omitted.