Patent ID: 6782700
Filing Date: 2004-08-31
Classification: F25B

Abstract:
A transient temperature control system for preventing collisions during a transient cool-down temperature range of a free piston cooler from a first operating temperature of a cold head to a set point operating temperature, the cooler having a piston reciprocating in linear oscillation within a cylinder at a variable stroke, the system comprising:(a) a cold head temperature sensor for sensing the temperature of the cold head and generating a temperature signal; (b) a relational interface in communication with the temperature signal and containing a predetermined relationship between the cold head temperature and a maximum piston stroke during the transient cool-down temperature range, the relational interface generating a transient range maximum allowable stroke signal from the temperature signal and the predetermined relationship; and (c) a temperature controller in communication with the relational interface, capable of receiving the transient range maximum allowable stroke signal and limiting the stroke to prevent collisions within the cooler during the transient cool-down temperature range, and capable of controlling the stroke of the piston while the cold head operates at approximately a steady state cold head temperature.