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:
Jan. 05, 1999
Filed:
Feb. 13, 1997
Anthony G Liepert, Lincoln, MA (US);
Varian Associates, Inc., Palo Alto, CA (US);
Abstract
A fluid handling apparatus, particularly a vacuum pump, has as a first stage a high volumetric displacement rate scroll pump of multiple nested interacting pairs of fixed and movable spiral-shaped blades supported in a housing between an inlet and an outlet. Each adjacent blade pair closes one inter-blade pocket in each cycle of operation. For very low base pressure vacuum applications, the adjacent blades extend about two revolutions to produce plural pockets in series. A second scroll pump mounted in the housing has its inlet fed directly from the first scroll outlet. The second scroll has a single pair of co-acting fixed and movable blades with multiple revolutions. A central drive shaft rotating in main bearings has an eccentric portion coupled to a plate that carries the movable blades of both scroll pumps. Synchronization cranks constrain the plate to orbit, not rotate. A purge gas flows over the crank bearings to sweep away and/or dilute corrosive fluids. It exhausts within the pump to the inter-stage pressure at the second stage inlet without adversely affecting the pump inlet pressure. Another purge gas flow sweeps corrosive gases from the main bearings, preferably formed as two sets of angular contact ball bearings aligned axially and oriented back-to-back.