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:
Apr. 28, 1981
Filed:
Jul. 18, 1980
Clifford M Peters, Longview, TX (US);
W-K-M Wellhead Systems, Inc., Shreveport, LA (US);
Abstract
A relay valve for controlling fluid flow to and from a valve actuator included in a safety system for a flowline such as a production line of an oil or gas well. The relay includes a slide valve (60) which is manually pushed inwardly to the open or set position and held therein by pilot fluid which is also applied to the valve actuator. A visual indicator mounted on a knob (102) of the slide valve is operated by fluid applied to a passage (96) formed in the slide valve. A vent port (82) prevents pilot pressure from moving the slide valve from the closed position to the open position. A modified relay valve (150) has separate inlet ports (198 and 200) for receiving pilot fluid and actuator fluid and a vent port (206) which is in direct fluid communication with the pilot port in the closed position of the slide valve.