| abstract |
(57) [Summary] In a two-stage compression refrigeration system using a two-stage compressor, refrigerating machine oil is filled in a closed housing of the two-stage compressor without passing through a compression mechanism having a large flow resistance. Thus, a sufficient amount of refrigerating machine oil is filled in the closed housing of the two-stage compressor. SOLUTION: A refrigerator oil filling pipe communicating with a closed housing of a two-stage compressor accommodating a low stage compression mechanism and a high stage compression mechanism is provided, and the refrigerator oil filling pipe is provided in the refrigerator oil filling pipe. To charge the refrigerating machine oil. |