Patent ID: 8276400

Claim:
A refrigeration apparatus, comprising: a refrigerant circuit comprising a higher stage compression mechanism formed of one or more compressors and a lower stage compression mechanism formed of one or more compressors, the higher stage compression mechanism and the lower stage compression mechanism being connected together in series to perform a two-stage compression refrigeration cycle, and an oil separator, disposed in a discharge pipe of the lower stage compression mechanism in the refrigerant circuit, for separating refrigeration oil from refrigerant discharged from the lower stage compression mechanism, wherein the refrigeration apparatus includes an oil return passageway, the oil return passageway extending from a compressor, the compressor constitutes the lower stage compression mechanism for connection to a downstream side of the oil separator whereby refrigeration oil accumulated in the compressor can be supplied to the higher stage compression mechanism, wherein, in the oil return compressor as a compressor to which the oil return passageway is connected, a discharge pressure space filled with refrigerant after compression is formed in a casing thereof, and the oil return passageway opens into an oil sump in the discharge pressure space, and wherein pressure reducing means for reducing the pressure of refrigerant flowing towards the oil separator from the oil return compressor is disposed between the oil return compressor and the oil separator in the discharge pipe of the lower stage compression mechanism.