PURPOSE: To prevent hunting from occurring by inputting temperature signals from a temperature measuring sensor provided at the inlet or body of an evaporator, and a temperature measuring sensor provided at the outlet of an intermediate cooler for feeding mixed refrigerant to an intermediate pressure expansion valve controller.
CONSTITUTION: The valve opening of a main expansion valve 5 is controlled in the same manner as that in a conventional one, but an intermediate pressure expansion valve 3 is controlled at its valve opening by inputting temperature signals from a temperature measuring sensor 8 provided at the inlet of an evaporator 6 and a temperature measuring sensor 12 provided at the outlet of an intermediate cooler 4 for feeding mixed refrigerant to an intermediate pressure expansion valve controller 13, calculating an output signal therein, then feeding the signal to the valve 3. A temperature measuring sensor is provided at the inlet of the evaporator to measure the evaporating temperature of the refrigerant in the evaporator, but the sensor may be provided at the body of the evaporator to measure the evaporating temperature of the refrigerant in the evaporator.
HARA KOJI
OCHI MASAO
