| 摘要 |
A bridge circuit (11) having four check valves (31, 32, 33, 34) is provided upstream of a receiver (10), which is provided upstream of an expansion valve (7). A gas vent pipe (12) for connecting the receiver (10) and a pipe (24) downstream of the expansion valve (7) to each other is provided, and the gas vent pipe (12) is provided with a gas vent valve (13). Upon shut down, the gas vent valve (13) is opened, and the expansion valve (7) is gradually closed. The compressor (4) is shut down and the gas vent valve (13) is closed after passage of a predetermined time from the point in time when the expansion valve (7) reaches the fully closed state. |
