A pivoting piston machine includes a housing, a first piston and a second piston arranged in the housing, the first and second pistons being pivotable away from one another and toward one another about a pivot axis. The machine has a working chamber arranged between first and second piston. The working chamber increases and decreases in size in alternating fashion during pivoting of the first piston and of the second piston. The machine also has a inlet mouth for admission and discharge of the working medium. A closing element for closing and opening the inlet or the outlet has a valve disk interacting with a valve seat. Either the inlet mouth or the outlet mouth is arranged within the working chamber between the first end surface and the second end surface, and the valve seat and the valve disk are arranged at either the inlet mouth or the outlet mouth.

Gas expansion device for expanding a gas or a gas-liquid mixture, where the gas expansion device includes a gas expansion element with an inlet port for the gas to be expanded and an inlet pipe for the gas to be expanded. The inlet pipe is connected to the inlet port where the gas expansion device includes a first liquid injection point for the injection of liquid, where the first liquid injection point is at a position level with the inlet port or upstream from the inlet port.

Liquid-injected compressor element or expander element with a housing that comprises a rotor chamber in which at least on rotor is rotatably affixed, whereby the element is further provided with a connection for an injection circuit for the injection of liquid into the element, whereby the connection to the injection circuit is realised by means of an injection point in the housing that opens into the first compression chamber or expansion chamber. The connection to the injection circuit is additionally realised by means of an additional injection point in the housing that opens into a second or subsequent compression chamber or expansion chamber.

Gas expansion device for expanding a gas or a gas-liquid mixture, where the gas expansion device includes a gas expansion element with an inlet port for the gas to be expanded and an inlet pipe for the gas to be expanded. The inlet pipe is connected to the inlet port where the gas expansion device includes a first liquid injection point for the injection of liquid, where the first liquid injection point is at a position level with the inlet port or upstream from the inlet port.

In order to improve an expansion system for a working medium that is used in particular in a circulating process of a system that utilises waste heat, in particular in a system operating in a Rankine cycle, comprising an expansion device coupled to an electricity generator, for the working medium, an inlet for supplying the pressurised working medium, and an outlet for the working medium that has been expanded by the expansion device, it is proposed that an aerosol generator unit that generates a lubricant aerosol should be associated with the inlet, wherein the working medium guided to the expansion device flows through this aerosol generator unit, which has a flow guide for the working medium having a concentration section that concentrates lubricant entrained in the total mass flow of working medium supplied to the expansion device to give aerosol particles, and these aerosol particles leave the concentration section together with a partial mass flow of the working medium, branching off from the total mass flow of working medium, as a lubricant aerosol mass flow, and that a line system should be provided that guides the lubricant aerosol mass flow to lubrication points of an expansion arrangement of the expansion device, for the purpose of aerosol lubrication.

Liquid-injected compressor element or expander element with a housing that comprises a rotor chamber in which at least on rotor is rotatably affixed, whereby the element is further provided with a connection for an injection circuit for the injection of liquid into the element, whereby the connection to the injection circuit is realised by means of an injection point in the housing that opens into the first compression chamber or expansion chamber. The connection to the injection circuit is additionally realised by means of an additional injection point in the housing that opens into a second or subsequent compression chamber or expansion chamber.

In order to improve an expansion system for a working medium that is used in particular in a circulating process of a system that utilises waste heat, in particular in a system operating in a Rankine cycle, comprising an expansion device coupled to an electricity generator, for the working medium, an inlet for supplying the pressurised working medium, and an outlet for the working medium that has been expanded by the expansion device, it is proposed that an aerosol generator unit that generates a lubricant aerosol should be associated with the inlet, wherein the working medium guided to the expansion device flows through this aerosol generator unit, which has a flow guide for the working medium having a concentration section that concentrates lubricant entrained in the total mass flow of working medium supplied to the expansion device to give aerosol particles, and these aerosol particles leave the concentration section together with a partial mass flow of the working medium, branching off from the total mass flow of working medium, as a lubricant aerosol mass flow, and that a line system should be provided that guides the lubricant aerosol mass flow to lubrication points of an expansion arrangement of the expansion device, for the purpose of aerosol lubrication.