The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 14, 1987
Filed:
Jul. 03, 1985
Philip A Lessard, Acton, MA (US);
Allen J Bartlett, Milford, MA (US);
John F Peterson, Lynnfield, MA (US);
Helix Technology Corporation, Waltham, MA (US);
Abstract
To control the temperature of one or more heat sinks of a cryogenic refrigerator in a cryopump, refrigerant gas to the refrigerator is diverted through heat exchangers associated with the refrigerator heat sinks. The diverted refrigerant gas may be used to maintain the temperature of the first stage cryopumping surfaces above some level to avoid cross over hangup. The second stage cryopumping surfaces may be warmed by the diverted refrigerant to some temperature level for partial regeneration. Both heat sinks may be warmed for full regeneration of the cryopump. Bleed flow of refrigerant gas cooled by the first stage of the refrigerator can be directed past a thermal mass to cool that mass. By reversing the flow of refrigerant gas during cooldown of the system, the thermal mass can be used to more rapidly cool the refrigerator. The thermal mass is thermally isolated from the refrigerator heat sinks and is positioned within the vacuum vessel of the cryopump adjacent to the first stage of the refrigerator.