Patent ID: 7089750

Claim:
A cryogenic refrigeration system comprising: an expansion nozzle having a high-pressure nozzle inlet and a low-pressure nozzle outlet; an expansion volume in gaseous communication with the nozzle outlet; and a compressor comprising a reciprocating compression device operable to compress gas within a compression volume, wherein the compression volume has an inlet port and an outlet port, a flapper inlet valve having an inlet valve inlet, and an inlet valve outlet in gaseous communication with the inlet port of the compression volume, wherein the inlet valve opens when a gaseous pressure at the inlet valve inlet is sufficiently greater than a gaseous pressure in the compression volume to overcome a spring force of the flapper inlet valve, and a flapper outlet valve having an outlet valve inlet in gaseous communication with the outlet port of the compression volume, and an outlet valve outlet in gaseous communication with the nozzle inlet, wherein the outlet valve opens when a gaseous pressure in the compression volume is greater than a gaseous pressure at the outlet valve outlet to overcome a spring force of the flapper outlet valve; and a drive motor system in driving mechanical communication with the compression device, wherein the compression volume is hermetically isolated from the drive motor system.