Abstract: This invention relates to an improvement in a rotary piston machine comprising a jacket and two side parts forming a housing, inlet and outlet means on said housing, a piston patterned after a saddle-free epitrochoid 1:1 mounted in said housing for rotation on an eccentric shaft, annularly-closed axial seals on the sides of the piston in proximity to the piston edge, and a pair of oppositely-positioned radial seals in said housing, the improvement comprising that the axial seal on each side of the piston is composed of two seal means equidistant with respect to each other and being closed within themselves, and lubricant opening means in said side parts in proximity to at least one of said radial seals, said openings being located essentially in the interstice between said two seal means in any position of the piston, or being covered temporarily at least in part by one of said two seal means.

Abstract: This invention relates to an improvement in a rotary piston machine of trochoidal construction for compressing a gaseous medium having working chambers between a trochoidal piston and a housing corresponding to the coordinated outer envelope curve, said working chambers being separated from each other by radial seals in the housing, and outlet openings closed-off by means preventing backflow for discharging medium from the working chambers, the improvement comprising trough-shaped recess means in the peripheral piston surface which, in the dead center position of the piston, are positioned immediately ahead of a radial seal.