Patent ID: 8398053

Claim:
A double piston, trunnion-mounted ball valve structure comprising: a valve body defining an internal cavity and a longitudinal bore; a rotatable, longitudinally moveable ball element positioned in the cavity and comprising a fluid flow passage therethrough when in a flow position; first and second longitudinally moveable piston seats, the first seat located upstream of the ball element, the second seat located downstream of the ball element; a upper trunnion fixedly engaging the ball element, one or more portions of the upper trunnion disposed within one or more first corresponding recesses of the valve body, at least one of the one or more first corresponding recesses containing a bias element exerting force on the upper trunnion in a direction of the first piston seat to oppose a load force acting on the ball element; and a lower trunnion fixedly engaging the ball element, one or more portions of the lower trunnion disposed within one or more second corresponding recesses of the valve body, at least one of the one or more second corresponding recesses containing a bias element exerting force on the lower trunnion in a direction of the first piston seat to oppose a load force acting on the ball element.