To reliably prevent the occurrence of the overheating state of a discharge pipe temperature by predicting the future prediction value of a discharge pipe temperature and performing control of prediction based on the prediction value.
In a refrigerating device formed such that a compressor 1, a heat-exchanger 3 on the heat source side, a motor-driven expansion valve 4, and a heat-exchanger 5 on the utilization side are interconnected, in the order, a discharge temperature detecting means (a discharge temperature sensor 19) detects the discharge pipe temperature of the compressor 1 and an overheating protection control means determines a discharge pipe temperature after a lapse of a given time from a past history of a discharge pipe temperature detected by the discharge temperature sensor 19 and performs overheating protection operation when the prediction value exceeds a preset set value, the two means being annexed. Overheating protection operation is carried out when the prediction value of a discharge pipe temperature after a lapse of a given time determined from the past history of the discharge pipe temperature exceeds a preset set value.
YAMAMOTO MASAKI
TAKECHI HISASHI
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