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. 12, 1977
Filed:
Feb. 06, 1974
Richard E Wells, Westminster, CA (US);
Victor E Derval, Seal Beach, CA (US);
John D Muchow, Cerritos, CA (US);
Willis Oil Tool Co., Long Beach, CA (US);
Abstract
A shut-off valve in a fluid line closes by spring pressure and/or line pressure and incorporates a control chamber wherein pressurized control fluid acting on a piston opens the valve in opposition to the spring pressure and/or line pressure. A 3-way actuator pilot normally places the control fluid in communication with the control cylinder but when vented cuts off the control supply fluid and releases the pressurized control fluid from the control chamber to cause the shut-off valve to close by spring pressure and/or line pressure. A monitor pilot responsive to pressure changes in the fluid line incorporates a relief valve and opens the relief valve by cam action to vent the actuator pilot whenever the pressure in the fluid line makes a predetermined departure from a normal pressure range.