Abstract: A free-piston reciprocating compressor includes a reciprocating piston disposed within a cylinder such that one end of the piston-cylinder provides for a compression space and the other end of the piston-cylinder provides for a balancing space. The piston is coupled to and reciprocatingly driven by the armature of a linear electrodynamic motor, which armature reciprocates on guide means. The compressor also includes porting means operative to establish a stabilizing gradient sufficient to keep the piston operating at a related fixed mid-stroke position. The motor armature is also coupled to a centering-resonance spring.

Abstract: A pump having a pump body (1), a push-rod (7), a diaphragm (8) with an aperture (17) and a plate valve (9). The push-rod (7) is driven by a motor (10) and is guided centrally in an elastic filter disk (13) mounted in a pump casing (3). A lower end of the push-rod (7) is provided with a dome (12) member by which the diaphragm (8) is pressed into a correspondingly shaped recess (15).