Patent ID: 6609382
Filing Date: 2003-08-26
Classification: F17C,F25D

Abstract:
A method of temperature control in a cryogenic system comprising:providing a motor speed sensor, the motor speed sensor being operatively coupled to a proportional-integral-derivative controller, the motor speed sensor determining a motor speed and sending the motor speed to the proportional-integral-derivative controller; providing a pressure sensor, the pressure sensor being operatively coupled to the proportional-integral-derivative controller, the pressure sensor determining a cryogenic pressure, and sending the pressure to the proportional-integral-derivative controller; providing a temperature sensor in the conditioned space, the temperature sensor being operatively coupled to the proportional-integral-derivative controller, the temperature sensor measuring a temperature within the conditioned space and sending the temperature to the proportional-integral-derivative controller; providing a deprived integral region in a proportional band to the proportional-integral-derivative controller when the motor speed is close to a motor speed set point; and generating an overriding control signal at the proportional-integral-derivative controller when the temperature and the pressure are beyond a temperature set point and a pressure set point.