HOT GAS DEFROSTING TYPE FREEZING/REFRIGERATION DEVICE AND DEFROSTING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a hot gas defrosting type freezing/refrigeration device and its defrosting method capable of positively preventing occurrence of hammering phenomenon or liquid returning state when an evaporating part is defrosted by hot gas and effectively defrosting at the evaporating part.SOLUTION: A high pressure side pipe 17a and a low pressure side pipe 17b of a main pipe 17 are communicated to each other by a bypass pipe 18 provided with a flow passage opening or closing valve 23 of which opening operation is controlled by control means 20. During a defrosting operation, a compressor 12 is stopped, a flow rate of refrigerant gas supplied from the high pressure side pipe 17a to the low pressure side pipe 17b is gradually increased and pressures at both pipes 17a, 17b are gradually balanced and after this state, the compressor 12 is energized again and defrosting operation is carried out under a state in which an operation frequency of the compressor 12 is adjusted to a lower defrosting operation frequency than a cooling operation frequency by an invertor 24.