Micro-cryogenic system with pseudo two stage cold finger, stationary regenerative material, and pre-cooling of the working fluid

摘要

A miniature cryogenic system preferably operating in a manner similar to a split Stirling cycle utilizes a cold finger with a solid, low weight displacer and a stationary regenerative material external to the displacer. The regenerative material preferably surrounds the displacer and extends from a fluid inlet to a cooled end plate of a housing. The displacer has a central channel that receives an auxiliary displacer that carries a regenerative material in an internal cavity. A second fluid inlet located at the end of the housing opposite the cooled end communicates with the regenerative material held in the auxiliary displacer. The main and auxiliary displacers preferably have associated heat exchangers at their cooling ends and the cooling end of the auxiliary displacer is located to pre-cool the fluid passing from the first inlet to the cooled end plate.