US Patent 7856818 Compressor

A compressor having a discharge chamber into which compressed refrigerant gas is discharged, a discharge passage connected to the discharge chamber, an oil separation device that centrifugally separate oil from the refrigerant gas, an oil reservoir chamber that communicates with a separation chamber through an oil passage and retains the oil separated from the refrigerant gas, and a filter provided between the separation chamber and the oil passage is disclosed. The oil reservoir chamber communicates with a low pressure zone in the compressor the pressure of which is lower than the pressure in the discharge chamber. The oil reservoir chamber thus supplies the separated oil to the low pressure zone. The oil separation device is arranged in the discharge passage in such a manner as to define the separation chamber. The oil separation device centrifugally separate the oil from the refrigerant gas by causing swirling of the refrigerant gas that has been sent to the separation chamber. The filter extends in a swirling direction of the refrigerant gas in the separation chamber.