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. 19, 2010
Filed:
Jun. 20, 2003
Martin Ernst Tollner, Eastbourne, GB;
Martin Ernst Tollner, Eastbourne, GB;
Edwards Limited, Crawley, West Sussex, GB;
Abstract
A method of operating apparatus for controlling the pressure in a process chamber (), the apparatus comprising a first pump unit () having an inlet in fluid connection with an outlet of said process chamber, and a second pump unit () having an inlet in fluid connection with an outlet of the first pump unit via a flow control unit () comprising a variable flow control device () having variable conductance for controlling outlet fluid pressure at the outlet of the first pump unit, the method comprises controlling speed of the first pump unit to increase the range of chamber pressures over which control of the outlet fluid pressure produces changes in said chamber pressure without exceeding the thermal limit and/or motor stall limit of the first pump unit.