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:
Feb. 07, 1995
Filed:
Sep. 02, 1993
Huruli D Kishorenath, San Jose, CA (US);
Johan E de Rijke, Cupertino, CA (US);
Mark O Foreman, Stockton, CA (US);
Ebara Technologies Incorporated, Santa Clara, CA (US);
Abstract
Apparatus and method for vacuum pumping an enclosed chamber includes a cryogenic pumping device in fluid communication with the chamber for removing gases from the chamber. The cryogenic pumping device includes a cooled pumping surface and an expander for expanding a compressed gas and thereby cooling the pumping surface. The vacuum pumping apparatus further includes a sensor for sensing an operating parameter, such as temperature, of the cryogenic pumping device and a controller responsive to the sensor for controlling the operating speed of the expander to produce a desired value of the operating parameter. Typically, the sensor is a temperature sensor, and the controller controls the speed of the expander motor.