Bi-directional Standard soft-seated ball valves can shut-off flow in either forward or reverse direction. As they have two soft seats and a pressure-assisted, floating ball. However, power plant ball valves are most uni-directional shut-off valves with a non-floating ball design. They have only one seat located downstream of the ball. This downstream seat, the upstream bearing ring, the conical load spring, and the ball are a matched set, fitted very precisely into the body cavity. Therefore, when assembled, the final stack height does not allow the ball to float.