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:
Jan. 05, 1993
Filed:
Oct. 25, 1991
Neil H Akkerman, Houston, TX (US);
AVA International, Inc., Houston, TX (US);
Abstract
There is disclosed a subsurface tubing safety valve comprising a body having ports therein connecting the bore of the body with the annulus thereabout, a sleeve for reciprocating in the body between positions opening and closing the ports, and a piston which reciprocates within the sleeve, and a pair of coil springs, a first of which acts between the piston and sleeve and a second of which acts between the sleeve and body. When the sleeve is raised to its open position, the piston may be caused to move upwardly within the sleeve in response to a predetermined increase in pressure differential acting upwardly across the piston so as to compress and generate energy in both springs. As the piston moves up, the sleeve is connected to it for downward movement therewith in response to a predetermined decrease in the pressure differential across the piston to a position in which the sleeve is released by an expandable end of a bellows in response to a predetermined drop in the pressure of the well fluid.