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. 26, 1980
Filed:
Sep. 12, 1977
Robert H Dean, Evanston, IL (US);
Oliver Q Dyer, Hoffman Estates, IL (US);
International Telephone and Telegraph Corporation, New York, NY (US);
Abstract
A backflow prevention device is disclosed which includes a pressure differential relief valve. The relief valve includes a lift chamber functioning to accelerate opening of the valve to assure that the valve fully opens once it has partially opened. The relief valve also includes construction features which allow control of the opening timing of the valve and which cause added closing force to be applied on the valve member to provide more positive closure thereof. Furthermore, a member is provided which substantially eliminates transfer of torque from a spring in the relief valve to a diaphragm therein and substantially eliminates angular cocking of the moveable valve assembly also in the relief valve.