Contoured integrated seat for ball valve

A valve comprising:

• a hollow valve body having an inlet and an outlet;
• a ball positioned within the hollow valve body, wherein the ball is rotatable between an open position and a closed position to control flow through the hollow valve body from the inlet to the outlet;
• an upstream sealing assembly within the body on an inlet side of the ball, wherein the upstream sealing assembly includes a seat coupled to rotate with the ball inside the hollow valve body between the open and closed positions and a counterseat installed in the body;
• and
• a downstream sealing assembly within the body on an outlet side of the ball, wherein the downstream sealing assembly also includes a seat coupled to rotate with the ball inside the hollow valve body between the open and closed positions and a counterseat installed in the body;
• wherein the counterseat of the upstream sealing assembly and the counterseat of the downstream sealing assembly are movable within the hollow valve body along a flow path from the inlet to the outlet during valve operation, and the seat of the upstream sealing assembly and the seat of the downstream sealing assembly are radially movable with respect to the ball during valve operation.

A method comprising:

• receiving fluid in a ball valve having:
• a hollow main body, a ball rotatable within the hollow main body between an open position and a closed position to control flow of the fluid through the ball valve, a seat disposed on and rotatable with the ball, and a counterseat in the hollow main body;
• rotating the ball to the closed position, wherein rotating the ball to the closed position causes:
• the seat to seal against the counterseat, and pressure from the fluid to push the seat away from the ball and against the counterseat;
• and
• rotating the ball from the closed position toward the open position, wherein rotating the ball from the closed position toward the open position causes the seat to contract radially inward with respect to the ball and to separate from the counterseat.