Well safety valve

Abstract From the Canadian patent

Abstract of the Disclosure A well safety valve, connectable in a tubing string for controlling fluid flow therethrough, in which the valve closure means is operated by a longitudinally movable telescoping, tubular operating member. High differential pressure across the closed valve closure means causes the tubular operator to telescope preventing damage to the closure means. The telescoping tubular operator extends automatically upon release of the high differential pressure. A piston rod type equalizing valve is provided which is engageable with the tubular operator in order to reduce pressure differential across the closure means prior to closure member opening forces being applied to the …