Patent ID: 7896627

Claim:
A rotary type expander comprising: a plurality of rotary mechanism parts, each rotary mechanism part including a single cylinder both ends of which are closed, a single piston for forming a fluid chamber within the cylinder, and a single blade for dividing the fluid chamber into a high-pressure chamber of high-pressure side and a low-pressure chamber of low-pressure side; and a single rotating shaft which is provided with eccentric parts for engagement with the piston, the eccentric parts being the same in number as the plurality of rotary mechanism parts; wherein: the plural rotary mechanism parts have different displacement volumes from each other and are connected in series in ascending order of their displacement volumes; in a former-stage-side one of the rotary mechanism parts and a latter-stage-side one of the rotary mechanism parts which are fluidly connected together, fluid flows into the high-pressure chamber of the latter-stage-side rotary mechanism part from the low-pressure chamber of the former-stage-side rotary mechanism part, while the blades of the plural rotary mechanism parts reach their respective most withdrawn positions relative to the direction of the outer periphery of the cylinder substantially simultaneously relative to a particular rotational angle of the rotating shaft.