DEFROSTING METHOD AND DEFROSTING DEVICE OF AIR REFRIGERANT TYPE FREEZING APPARATUS

摘要

PROBLEM TO BE SOLVED: To provide an air refrigerant type freezing apparatus that enables an efficient defrosting-energy-saving operation, shortens the defrosting process time, and improves its operability.

SOLUTION: A defrosting device of the air refrigerant type freezing apparatus includes: a first bypass passage 38 that bypasses a compartment 32 to supply an air refrigerant on an outlet side of an expander to an inlet side of a frosting trap 34; a second bypass passage 36 that bypasses the compartment 32 to supply an air refrigerant on an outlet side of a primary cooler 22 to an inlet side of an expander 18; a pressure sensor 50 which detects an inlet pressure of a compressor 12; a temperature sensor 51 that detects a refrigerant temperature T1on an inlet side of the compressor; temperature sensors 52 and 53 that detect the air refrigerant temperature T2and air refrigerant passage wall temperature T3in an inlet area on a low temperature side of a heat recovery unit 30; and a temperature sensor 54 that detects a refrigerant temperature T4on an outlet side of the compressor. The defrosting process finishes when the air refrigerant passage wall temperature T3reaches the melting completion temperature Tg of 2-7°C while maintaining the air refrigerant temperature T1on the inlet side of the compressor at the set value Tcs during the defrosting operation.

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