Patent ID: 8056361

Claim:
A multi-stage rotary-type fluid machine comprising: a first cylinder; a shaft penetrating the first cylinder; a first piston fitted to the shaft and rotating eccentrically in the first cylinder; a second cylinder disposed concentrically with the first cylinder so as to share the shaft with the first cylinder; a second piston fitted to the shaft and rotating eccentrically in the second cylinder; a first partitioning member fitted into a first groove formed in the first cylinder, for partitioning a space between the first cylinder and the first piston into a first suction side space and a first discharge side space; a second partitioning member fitted into a second groove formed in the second cylinder, for partitioning a space between the second cylinder and the second piston into a second suction side space and a second discharge side space; an intermediate plate having a communication hole for allowing communication between the first discharge side space and the second suction side space to form a single working chamber, the intermediate plate partitioning the first cylinder and the second cylinder; a suction port for drawing a working fluid into the first suction side space; and a discharge port for discharging the working fluid from the second discharge side space, wherein an opening shape and a location of the communication hole are set so that direct blow-through of the working fluid from the suction port to the discharge port cannot occur at any rotation angle of the shaft.