Patent ID: 8177525

Claim:
An expander-integrated compressor comprising: a closed casing having a bottom portion utilized as an oil reservoir, and an internal space to be filled with a working fluid compressed to a high pressure; a compression mechanism for compressing the working fluid and discharging the working fluid to the internal space of the closed casing, the compression mechanism being disposed at an upper part of the closed casing; an expansion mechanism for recovering mechanical power from the expanding working fluid, the expansion mechanism being disposed at a lower part of the closed casing in such a manner that a space surrounding the expansion mechanism is filled with an oil held in the oil reservoir; a shaft coupling the compression mechanism and the expansion mechanism so as to transfer the mechanical power recovered by the expansion mechanism to the compression mechanism; an oil pump for drawing the oil held in the oil reservoir via an oil suction port and supplying the oil to the compression mechanism, the oil pump being disposed between the compression mechanism and the expansion mechanism in an axial direction of the shaft; and a heat insulating structure for suppressing heat transfer from an upper tank, in which the oil suction port is located, to a lower tank, in which the expansion mechanism is located, by limiting a flow of the oil between the upper tank and the lower tank, the heat insulating structure being disposed between the oil pump and the expansion mechanism in the axial direction of the shaft.