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:
Feb. 11, 1992
Filed:
Nov. 19, 1990
Roy N Peacock, Lafayette, CO (US);
Lee E Vestman, Lakewood, CO (US);
MKS Instruments, Inc., Andover, MA (US);
Abstract
A vacuum processing system and method by which system turbulence is reduced utilizing a vacuum responsive flow controlling valve that is located between a vacuum pump and a vacuum processing chamber to restrict the rate of pumpdown. A valve member of the flow controlling valve, such as a butterfly valve closure plate, is positionally shifted by a pressure differential responsive actuator as a function of the extent to which the pressure in the vacuum processing chamber has been reduced by the pump. During the initial phase of pumpdown, the valve closure member is in its maximally closed position, with evacuation of the vacuum processing chamber occurring solely through a leakage path past the valve member. After a predetermined pressure is reached, the valve member slowly opens as the pressure differential in the actuator increases, until a maximally open position is achieved.