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:
Oct. 23, 2007
Filed:
Jan. 28, 2003
Keiji Emoto, Tochigi, JP;
Katsunori Onuki, Ibaraki, JP;
Keiji Emoto, Tochigi, JP;
Katsunori Onuki, Ibaraki, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Hitachi High-Technologies Corporation, Tokyo, JP;
Abstract
An exhaust apparatus for a differential exhaust mechanism having a labyrinth seal and a plurality of vacuum pockets includes a differential exhaust system for evacuating the vacuum pockets and an exhaust system for evacuating a chamber of exhaust gas. The differential exhaust system and the exhaust system are connected by control valves that can be opened and closed, enabling communication between the vacuum pockets and the interior of the chamber to be opened and closed (or connected and disconnected) as well. The valves are opened when a vacuum is being formed inside the chamber or when a malfunction occurs in the exhaust system, thus connecting the vacuum pockets and the chamber and preventing excessive pressure from building up on the hydrostatic bearing.