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:
Dec. 07, 2004
Filed:
Feb. 06, 2003
Chad M. Engle, Marshalltown, IA (US);
Lynn D. Mahncke, Marshalltown, IA (US);
Fisher Controls International LLC, St. Louis, MO (US);
Abstract
A control valve pressure actuator of the pressure-to-close type is provided with a housing in which an upper diaphragm casing thereof includes one or more air passage channels. Each of the air passage channels facilitates circulation of air above a diaphragm within the pressure actuator at all times, including when the diaphragm is in a fully open position. By permitting the circulation of air above the diaphragm even when in a fully open position, adjacent an inside surface of the top of the upper diaphragm casing, there is not a tendency for the diaphragm, biased toward the open position by springs, to stick to the inside surface of the top of the upper diaphragm casing.