To regulate quantities of oil for plural low pressure shell type compressors to a proper ones.
A variable speed side oil equalizing branch pipe 4 having one end in communication with the vicinity of the standard oil level of a variable speed compressor 1 and another end in communication with an oil equalizing pipe 3 is provided, a constant speed side oil equalizing branch pipe 5 having one end in communication with the vicinity of the standard oil level of a constant speed compressor 2 and another end in communication with the oil equalizing pipe 3 is provided, and a variable speed side two-way valve 6 is provided in the middle of the variable speed side oil equalizing branch pipe 4. Thereby, shortage of oil in each compressor is prevented by closing the variable speed side two-way valve 6 during cooling or heating operation, and opening it during oil equalizing operation.
KANEKO TAKASHI
KITAYAMA HIROSHI
MORIWAKI SHUNJI
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