Abstract: An improved ball-type valve apparatus adapted for use in flowlines which provide a straight through flow path which minimizes flow turbulance and flow resistance in either direction through the valve housing. The ball is rotated by a crank between the open and closed positions for controlling flow through the valve. Oppositely facing seat rings engage the ball on opposite sides to provide a dual redundant sealing system with the primary seals located at the upstream seat with the secondary seal formed at the downstream seat. An access plug retains the ball in the valve housing and is secured with the valve housing by a segmented locking ring. When the plug is removed from the housing maintenance or assembly access to the ball, seat rings and their retaining means without disturbing the connections of the valve housing in the flowlines is provided.

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.