US Patent 7870733 Fluid machine for rankine cycle

It is an object to provide a fluid machine, which is simple in structure and in which lubricating oil containing smaller amount of the working fluid is supplied to sliding portions of an expansion device. The fluid machine has the expansion device for generating a driving force by expansion of the working fluid, which contains the lubricating oil and is heated to a gas phase condition. The fluid machine further has an electric power generating device driven by the driving force of the expansion device and generating electric power. An oil pooling portion is formed in a fluid passage, through which the working fluid discharged from the expansion device flows, such that the lubricating oil contained in the working fluid is brought into contact with at least one of sliding portions of the expansion device and the electric power generating device. And a heating unit is provided to heat the working fluid in the oil pooling portion.