Cryogenic cooler with annular regenerator and clearance seals

摘要

A Stirling Cooler with a three stage cold finger. The finger includes a stepped displacer in a stepped cylinder. The cylinder is loosely surrounded by an outer shell, with regenerator material in the space between the outer shell and the cylinder. The displacer-cylinder define three swept expansion spaces each communicating with the regenerator space. Clearance seals exist between the displacer and the cylinder because of small diametrical clearance and long axial length with respect to the diametrical clearance.