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:
May. 09, 2000
Filed:
Aug. 28, 1998
Thomas Hofmann, San Diego, CA (US);
James Kevin Howey, Vista, CA (US);
Robert Alan Shannon, El Cajon, CA (US);
Richard Carl Ujazdowski, San Diego, CA (US);
Cymer, Inc., San Diego, CA (US);
Abstract
A tangential fan for recirculating a lasing gas mixture has blade members, which vary in circumferential position stepwise from end to end. The number of blade members can be constant or variable between ends. The circumferential position of blade members can shift monotonically or reversibly between ends. Blade members are stiffened by one or more transverse annular hub members. A method of forming a tangential fan involves forming monolithic structures by casting or by machining from a solid block. Two or more monolithic structures can be joined together, typically by electron-beam welding. Casting, welding, and machining processes introduce no additional contaminants. Tangential fans produced have mechanical rigidity, accurate tolerances, and low contaminant concentrations. Methods provided by the invention facilitate forming of blade members into an air foil shape. Finishing processes typically include post-machining, electropolishing, and electroless nickel coating.