Patent ID: 7412835

Claim:
An apparatus for adjusting stroke frequency of a cryocooler as a function of pressure in a cryogen pressure vessel, the apparatus comprising: a generator for setting an initial stroke rate for the cryocooler by setting alternating or direct current motor speed; a difference measuring device for continuously measuring in each cycle of operation a pressure difference between a measured pressure and a set pressure; a controller for calculating in each cycle of operation a required stroke rate or a frequency adjustment for the cryocooler from the measured pressure difference; a variable speed module for combining in each cycle of operation the stroke rate adjustment with the initial stroke rate to adjust the stroke rate or frequency by adjusting the alternating or direct current motor speed in order to optimize operations of the cryocooler; and a thermal gasket operably coupled between the cryocooler and a recondenser to provide a thermal interface, and pressure controller to selectively adjust a mechanical pressure across the thermal interface, a the pressure controller including a display to indicate a temperature drop across the thermal interface; wherein the variable speed module increases the cryocooler stroke rate by increasing the alternating or direct current motor speed when the measured pressure is greater than the set pressure.