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. 04, 2014
Filed:
Nov. 12, 2008
Toshio Suzuki, Chigasaki, JP;
Tomonari Tanaka, Chigasaki, JP;
Toshio Suzuki, Chigasaki, JP;
Tomonari Tanaka, Chigasaki, JP;
ULVAC, Inc., Chigasaki-Shi, JP;
Abstract
A multi-stage dry pump includes: a plurality of pump chambers each including a cylinder and a rotor housed in the cylinder; a first rotor shaft that is a rotation shaft of the rotors; a fixed bearing that rotatably supports the first rotor shaft and restricts a movement thereof along an axis direction of the first rotor shaft; and a free bearing that rotatably supports the first rotor shaft and permits a movement thereof along the axis direction of the first rotor shaft; wherein: the plurality of pump chambers is disposed between the fixed bearing and the free bearing; and a first pump chamber of the plurality of pump chambers which has a lower pressure and on the aspiration side is placed in proximity to the fixed bearing.