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:
Mar. 13, 2007
Filed:
May. 14, 2004
Anthony G. Liepert, Lincoln, MA (US);
Anthony G. Liepert, Lincoln, MA (US);
Varian, Inc., Palo Alto, CA (US);
Abstract
A vacuum pumping system includes a primary vacuum pump having an inlet for coupling to a system, and a secondary vacuum pump having an inlet coupled to the exhaust of the primary vacuum pump. The primary vacuum pump is an oil-free, positive displacement vacuum pump having multiple clearance seals between the inlet and the exhaust. The primary vacuum pump may be a scroll vacuum pump, and the secondary vacuum pump may be an oil-free diaphragm pump. The system may include a valve coupled to the exhaust of the primary vacuum pump and configured to couple the exhaust of the primary vacuum pump to an interpump exhaust in response to a selected condition, such as the pressure level at the exhaust of the primary vacuum pump.