Patent ID: 6732542
Filing Date: 2004-05-11
Classification: F01C,F04C,F25B

Abstract:
In a refrigerant circuit comprising:a rotary compressor that has a hermetic vessel housing an electromotive unit and first and second rotary compressing units driven by the electromotive unit, discharges a refrigerant gas that has been compressed by the first rotary compressing unit into the hermetic vessel, and further compresses the discharged, intermediate-pressure refrigerant gas by the second rotary compressing unit; a gas cooler into which the refrigerant discharged from the second rotary compressing unit of the rotary compressor flows; a decompressor connected to the outlet end of the gas cooler; and an evaporator connected to the outlet end of the decompressor, the refrigerant from the evaporator being compressed by the first rotary compressing unit, the rotary compressor comprising: a cylinder constituting the second rotary compressing unit and a roller that is fitted to an eccentric portion formed in a rotary shaft of the electromotive unit and eccentrically rotates in the cylinder; a vane abutted against the roller to partition the interior of the cylinder into a low-pressure chamber and a high-pressure chamber; a spring for constantly urging the vane toward the roller; and a back pressure chamber for applying the discharge pressure of the second rotary compressing unit to the vane as a back pressure, a defroster of the refrigerant circuit that, in order to defrost the evaporator, introduces the refrigerant gas discharged from the second rotary compressing unit into the evaporator without being decompressed by the decompressor, also introduces the refrigerant gas discharged from the first rotary compressing unit into the evaporator, drives the electromotive unit of the rotary compressor at a predetermined number of revolutions, and sets the inertial force of the vane at the predetermined number of revolutions to be smaller than the urging force of the spring.