Abstract: The external rotor of a single-rotation machine has engagement spaces, whose boundary faces in the inward direction form a widening, which is adjacent in an outer region radial thereto to parallel surfaces or surfaces forming a widening in the outward direction. The side walls axially bounding these engagement spaces have a radially outer part, which is cast in one piece with the peripheral parts of the external rotor and an inner part radial thereto, which subsequently reduces to a circular opening the opening surrounded by the radially outer parts, so that the radial seal between side walls and a stationary sealing member surrounded by said opening is located radially within the peripheral parts of the external rotor and a sealing gap in the radial plane between the peripheral parts and the sealing member is avoided.

Abstract: For an improved sealing at the sealing gaps of a single-rotation machine having internal axes and accompanied by minimum frictionally losses, the width of the sealing gaps is made to differ in such a way that the narrower sealing gaps occur on the radially outer circumferential surfaces of the internal rotor facing the engagement parts of the external rotor. The comparatively wider sealing gaps occur on the transition surfaces between radially inner circumferential surfaces and radially outer circumferential surfaces of the internal rotor.

Abstract: The engagement parts of the external rotor of a single-rotation machine having an internal axis with sealing between its rotors and with respect to the machine casing by sealing gaps, are manufactured as single parts and following reciprocal alignment are joined at their two ends to in each case one circular side part. Alignment takes place by engaging the cross-sectionally arcuate outer faces of the engagement parts on arcuate parts of an assembly cage and by dimensionally accurate assembly bodies engaging between the engagement parts. The method permits narrower sealing gaps for the machine and consequently an improved efficiency.

Abstract: An external shaft rotary piston machine wherein pistons of a piston rotor run in engagement with a cavity of a circular cylindrical sealing rotor during a particular relative rotational position of the rotors, the cavity being substantially larger than necessary for passage of the pistons in order to avoid flow losses due to seal wedging flow and compression. In order to avoid overflow from the high pressure side to the low pressure side of the machine through the sealing rotor while the pistons move in the sealing rotor through the space defined by the cavity, a sealing effect is created by a leading edge and a trailing edge portion of the opening of the cavity of the sealing rotor moving along a leading and a trailing side surface of the pistons. This is effected kinematically due to the fact that the trailing edge of the cavity opening is displaced radially inwardly and that an edge portion extends from the trailing edge convexly relative to the peripheral surface of the sealing rotor.

Abstract: The invention provides an ignition voltage supply system for a rotary piston engine. The engine itself has a housing with gas inlet and outlet openings, a shaft and a rotor eccentrically mounted on the shaft in the housing. The ignition voltage supply system includes sparking plugs arranged in the rotor and insulated feed members which are fixed to the rotor and connected to the plugs. An insulated distributor member is fixed to the shaft and distributes ignition voltage to each feed member, and a cable located in the shaft connects the distributor member to a source of electrical voltage. A lateral opening is provided in the gas inlet or outlet for fitting and removing a sparking plug.