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. 14, 1980
Filed:
Sep. 29, 1978
Kamil Prochazka, Windisch, CH;
Franz Suter, Gebenstorf, CH;
BBC Brown Boveri & Company Limited, Baden, CH;
Abstract
A valve actuator is disclosed having a servo-motor which regulates the position of a main valve that controls steam supply to a turbine. A hydraulic input signal acts on a pilot valve within the valve actuator body to move a valve spool in response to the input signal. Movement of the valve spool permits oil to flow into a cylinder in which the servo-motor is located. The flow of oil into the cylinder causes a piston which is a part of the servo-motor to move upwardly. Movement of the servo-motor is regulated by a cam and follower arrangement which transfers the motion of the servo-motor to a valve sleeve. The valve sleeve, which has a differential piston area, shuts-off the supply of oil to the servo-motor. The cam and follower arrangement provides for a linear correlation between the hydraulic input signal and the operation of the servo-motor. Increased closing forces provided by the differential piston reduce vibration of the valve sleeve and the servo-motor.