| 摘要 |
PURPOSE:To avoid overload operation, maintain stable operation and improve the thawing and cold-keeping performance by providing a suction pressure regulator on the low pressure side of a compressor, a capacity controller between the high pressure side and said regulator, a condensing pressure regulator between a first heat exchanger and a liquid receiver, and the first heat exchanger in a thawing apparatus with a humidified air circulating device. CONSTITUTION:During thawing operation, the super-heated gas compressed to a high pressure by a compressor 4 passes through a four-way changover solenoid valve 15, is condensed at a heat exchanger 5f, and flows into a liquid receiver 7 through a three-way condensing pressure regulating valve 18 and a check valve 6a. Then, the liquid passes through a second expansion valve 8, is vaporized at a second heat exchanger 9, and returned to the compressor 4 through the solenoid valve 15 and a suction pressure regulating valve 16. In the case of cold-keeping operation, the gas compressed to a high pressure by the compressor 4 is switched by the solenoid valve 15 to the heat exchanger 9 where the gas is condensed, and flows into the liquid receiver 7 through a back flow pipe 13 with a check valve 12a, and a check valve 14a. Then, the liquid passes through a first expansion valve 10 of a bypass pipe 11 to the heat exchanger 5 where the liquid is vaporized, and returned to the compressor 4 through the solenoid valve 15 and the regulating valve 16. The refrigerant is circulated as described above, and the heat exchanger 4 becomes low pressure and low temperature. |
