GB884454A - Control of apparatus operating at high and low temperatures - Google Patents

Abstract

884,454. Refrigerating systems. FRICK CO. June 3. 1960, No. 19788/60. Class 29 In a compression refrigerating system, evaporators may alternatively operate at pressures and temperatures above or below that of the condenser. For operating below the temperature and pressure of the condenser, evaporators in reaction vessels 10, 10<SP>1</SP> are supplied with liquid refrigerant from reservoir 29 by header 20 and lines 14 and 14<SP>1</SP>. The evaporated refrigerant is returned to compressor 34 through lines 36, 36<SP>1</SP> and header 37. For operating above the temperature and pressure of the condenser the evaporators are supplied from the reservoir by a pump 47 through header 24 and lines 22, 22<SP>1</SP>. The evaporated refrigerant is returned to condenser 33 through lines 38, 38<SP>1</SP> and header 39. If the liquid passage becomes blocked pump 47 may alternatively discharge through pressure sensitive valve 50 into the condenser 33. An automatic control 52 for valves 59, 61, 63, 59<SP>1</SP>, 61<SP>1</SP> and 63<SP>1</SP> is actuated by temperature or pressure sensitive devices 54, 55, 54<SP>1</SP> and 55<SP>1</SP> in the reaction vessels and in the refrigerant return lines 12, 12<SP>1</SP>. The controller 52 controls the evaporator temperature through pressure regulating valves 61 or 63 and automatically closes the valve 61 or 63 in the idle line. In another form (Fig. 2, not shown), in which two series of reaction vessels are arranged in cascade, a heat exchange is arranged between the evaporator going liquid refrigerant and the compressor going gaseous refrigerant but is bypassed by the pump circulated liquid refrigerant.