1. In the closed position, the ball is pressed against the valve seat by the mechanical of the valve stem.
2. When the hand wheel is turned counterclockwise, the valve stem moves in the opposite direction, and the angular plane at the bottom causes the ball to separate from the valve seat.
3. The valve stem continues to lift and interacts with the guide pin in the spiral groove of the valve stem, so that the ball begins to rotate without friction.
4. Until it reaches the fully open position, the valve stem is raised to the limit position, and the ball rotates to the fully open position.
