Stirling engine displacer suspension system

Abstract

A free piston Stirling engine includes a hermetically sealed vessel enclosing a working space which is filled with a working gas such as helium. A displacer is mounted in the working space on a suspension apparatus for axial reciprocation to displace working gas back and forth sequentially through a heater, a regenerator, and a cooler to create a cyclic pressure wave which drives a power piston. The displacer is connected to a mounting flange fixed to the vessel by a bellows which permits the displacer to move axially. A diaphragm is connected to the mounting flange and seals an oil cavity whose sides are defined by the bellows. The top of the oil cavity is formed by a transverse wall in the displacer, in which is formed a cylinder which receives a stationary piston mounted on a spider in the oil cavity and fastened to the mounting flange. The axial motion of the displacer is accommodated by the bellows, and the distributed pressure forces of the working gas pressure wave are conducted through the diaphragm and fluid in the cavity to the displacer transverse wall. The volumetric displacement of fluid in the cavity caused by axial expansion and compression of the bellows is accommodated by a corresponding displacement of the cylinder relative to the fixed piston, so the volume in the cavity stays virtually constant and the only substantial stress to which the diaphragm is subjected is the displacement induced stress that enables the diaphragm to function as a centering spring, and not pressure induced stress.

Dependencies are inferred from the claim text.