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:
Aug. 25, 1992
Filed:
May. 13, 1991
William W Dollison, Dallas, TX (US);
John C Gano, Carrollton, TX (US);
Otis Engineering Corporation, Dallas, TX (US);
Abstract
A retrievable subsurface safety valve positioned in a well conduit is actuated to close by a predetermined flow rate through the safety valve. A valve member having a sealing surface is moveable by flow to sealingly engage an annular seat in the valve, closing the valve to flow. All forms of the invention safety valve have retrievable variable weight assemblies which releasably lock in the valve member for varying the flow rate at which each valve closes. In two invention forms, the weight assemblies when retrieved from the valve members leave the valve members open for passage of well tools through the valve members. In one invention form, the valve housing has a variable bias for biasing the valve member toward open position and this safety valve may be operated to expend the seat, housing and valve member with or without the variable weight assembly.