Description of the process of opening and closing the three-piece manual vacuum ball valve

How the three-piece manual vacuum ball valve opens and closes during use.

First, the opening process

In the closed position, the ball is pressed by the mechanical pressure of the valve stem and pressed against the valve seat.
When the handwheel is turned counterclockwise, the valve stem moves in the opposite direction, and the bottom angular plane causes the ball to disengage from the valve seat.
The valve stem continues to lift and interacts with the guide pins in the stem groove of the valve stem, causing the ball to begin to rotate without friction.
Until the fully open position, the stem is raised to the extreme position and the ball is rotated to the fully open position.
Second, the closing process

When closed, turn the handwheel clockwise, the stem begins to lower and the ball moves away from the seat.
Continue to rotate the handwheel, the valve stem is subjected to the guide pin embedded in the upper spiral groove, so that the valve stem and the ball rotate 90° at the same time.
When it is about to close, the ball has rotated 90° without contact with the seat.
In the last few turns of the handwheel, the angular plane at the bottom of the valve stem mechanically wedges against the ball, causing it to press tightly against the valve seat for a complete seal.