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:
Oct. 13, 1981
Filed:
Dec. 31, 1979
Tosh Miyagishima, Los Angeles, CA (US);
Joseph Puntar, Los Angeles, CA (US);
Raymond Wieveg, Los Angeles, CA (US);
Hydril Company, Los Angeles, CA (US);
Abstract
An inside blowout preventer well tool includes an elongated body threaded at both ends and including an axial opening. A flapper is pivotally mounted on a side of the opening and movable between a lower-open position and an upper-closed position. A downwardly-facing valve seat is formed around the opening, the flapper engaging the seat in the upper-closed position. A spring urges the flapper toward the seat and a piston is movable in the opening between an upper position, where the lower end of the piston is above the valve seat, and a lower position, where the piston encases the flapper and holds it in the lower-open position. The piston is normally urged toward its upper position, the piston being shaped so that when the internal pressure of drilling mud normally circulating through the opening is greater by a predetermined amount than pressure outside the body, the pressure differential will overcome the force urging the piston upwardly and move the piston to the lower position. The piston is also responsive to fluid pressure outside the body so that the piston will automatically be moved to its upper position when the pressure differential is reduced by a predetermined amount.