Patent ID: 7273479
Filing Date: 2007-09-25
Classification: A61B,F25B

Abstract:
1. A method for cooling an object with a cryogen having a critical point defined by a critical-point pressure and a critical-point temperature, the method comprising: raising a pressure of the cryogen to between 0.8 and 1.2 of its critical-point pressure and providing the cryogen at a temperature within ±10% of its critical-point temperature; thereafter, reducing a temperature of the cryogen without decreasing the pressure of the cryogen below 0.8 times its critical-point pressure; thereafter, placing the cryogen in thermal communication with the object to increase the temperature of the cryogen to an ambient temperature along a thermodynamic path that maintains a pressure greater than 0.8 times the critical-point pressure for a duration that the cryogen and object are in thermal communication; thereafter, removing the cryogen from thermal communication with the object; and thereafter, reducing the pressure of the cryogen to an ambient pressure.