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:
Aug. 27, 2002
Filed:
Nov. 20, 2000
Robert W. Shaffer, Hamilton, OH (US);
Air Squared, Inc., Hamilton, OH (US);
Abstract
A scroll vacuum pump includes a first stage having a first stage fixed plate with a spiral involute, a second stage having a second stage fixed plate with a spiral involute wrap, and an orbiting plate having upper and lower surfaces. An involute spiral extends from the orbiting plate bottom surface to define a first stage orbiting plate and a second involute spiral extends from the orbiting plate top surface to define a second stage orbiting plate. The first stage involute wraps are taller than the second stage involute wraps. Gas is expanded in the first stage and compressed in the second stage. The first stage has an expansion ratio greater than or equal to one and the second stage has a compression ratio greater than or equal to one. However, that the pressure at the second stage exit is less than the pressure at the first stage inlet. To increase the efficiency of the pump, the tip seals of the involute spirals are extended as close as possible to the center of the involute to delay porting of gas by 180° of rotation.