| 摘要 |
<P>PROBLEM TO BE SOLVED: To prevent stagnation of a large quantity of the refrigerator oil in an evaporator. <P>SOLUTION: A check valve 81 is provided in a second oil return passage 80 for connecting a coolant outlet side of the evaporator 30 to a coolant suction side of a compressor 10, and the check valve 81 is set to be opened when the pressure of the coolant outlet side of the evaporator 30 becomes larger than the pressure of the coolant suction side of the compressor 10 and a pressure difference between them becomes the predetermined pressure difference or more. With this structure, when the refrigerator oil inside of the evaporator 30 is reduced, the check valve 81 is closed to automatically transfer operation mode from the oil return mode to the normal operation mode. Inversely, when a large quantity of the refrigerator oil inside of the evaporator 30 stays, the check valve 81 is opened to automatically transfer operation mode from the normal operation mode to the oil return mode, and the refrigerator oil staying in the evaporator 30 can be controlled to the predetermined rate or less to return a sufficient quantity of the refrigerator oil to the compressor 10. <P>COPYRIGHT: (C)2004,JPO |
