JPS54154853A - Freezer - Google Patents

Abstract

PURPOSE: For preventing the decrease of high- and low-pressure side pressures upon defrosting, to connect hot gas bypass pipes to the discharge side of a compressor and to the inlet side of an evaporator through the medium of flow course change-over valves and refrigerant recovery pipes to the outlet sides of said condenser and evaporator through the medium of solenoid valves.

CONSTITUTION: Initially in defrosting, the high temperature gas compressed at a compressor 1 flows in a evaporator 5 through a hot gas bypass pipe 13, passes through a refrigerant recovery pipe 17, flows from the outlet side of said evaporator 5 and is stored, and a branch pipe 20 returns a part of the liquid refrigerant present in a condenser 2 and a liquid receiver 3 to the low pressure side of said compressor 1 for preventing the decrease of low-pressure side pressure. When normal defrosting operation is started with the difference of pressure between said condenser 2 and evaporator 5 eliminated, the high temperature gas flowing in from said hot gas bypass pipe 13 condenses making heat exchange with the liquid refrigerant in storage, and said liquid refrigerant flows out of said evaporator 5. Said liquid refrigerant is returned to said accumulator 6 through a pressure adjusting valve 12, a heat accumulating tank 7 and said accumulator 6 for preventing the decrease of low and hgh pressure side pressures.

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