Design of a Continuous Duty Cryopump

摘要

A continuous duty cryopump system was designed and developed that comprises a self-contained cryopump for installation into a vacuum chamber, and a microprocessor controller for automatic operation. This deuterium pump has two units in a single housing, arranged so that one is pumping while the other is being regenerated. Liquid helium-cooled, finned sections in each unit pump deuterium by condensation, and a third pump integral within the cryopump housing collects the regenerated gas. A microprocessor unit controls distribution of liquid and gaseous helium, used for conditioning the pumping units, and operates remote actuators for the regeneration. Software provides fully automatic, timed sequencing of the repetitive cryopump events which include: cooldown of the pumping units, opening of the louvers isolating the unit from the vacuum chamber, closing of the louvers, and warming up of the unit for regeneration. Default values in the software can be reprogrammed by the operator through the keyboard in response to prompts displayed on the computer. An override allows the operator to control the cryopump manually by activating switches on a control panel. Interlocks to prevent cryogen lockup are included in the software. (ERA citation 11:055596)