| 摘要 |
PROBLEM TO BE SOLVED: To prevent seizure of a compressor by employing two high pressure compressors where delivery pressure acts on lubrication, providing the delivery and suction pipes of each compressor with check valves and providing an oil smoothing pipe communicating with lubricant in two compressors through an on/off valve. SOLUTION: At the time of simultaneous operation of two compressors 1a, 1b, refrigerant gas is sucked from suction pipes 13a, 13b and high pressure refrigerant gas is delivered from delivery pipes 11a, 11b. An on/off valve 9 is opened and an oil smoothing pipe 8 communicates with lubricant in respective compressors 1a, 1b to make uniform the level of lubricant through action of substantially identical delivery pressure. At the time of single operation of the compressor 1a, for example, the on/off valve 9 is closed and delivery pressure acts in the compressor 1a but pressure is balanced in the compressor 1b at an intermediate level between delivery pressure and suction pressure through function of check valves 10b, 12b. Consequently, lubricant is prevented from flowing from one compressor to the other.
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