FREEZING CYCLE

PROBLEM TO BE SOLVED: To provide a freezing cycle which need not be provided with a relief valve independently, in a freezing cycle which may get in the condition where the pressure of a high pressure line is over the critical pressure of a refrigerant. SOLUTION: A pressure controller, which depressurizes and expands a refrigerant cooled with a radiator has a housing which has a refrigerant flow inlet leading to the side of the radiator and a refrigerant flow outlet leading to the side of the radiator, a valve element 24 which changes the connection state between the inlet side of the refrigerant flow and the outlet side of the refrigerant flow, a first reply member 25 which couples with the valve element 24 within the housing and controls the quantity of lifting of the valve element 24 by sensing the refrigerant state on the side of the radiator an operating, a second reply means 26 which is provided with its operational direction in accord with the first reply member 25 and senses the refrigerant pressure on radiator side and operates and lifts the valve element compulsively in case that the pressure on the radiator side comes to specified pressure or over.