The three-piece ball valve is similar to the gate valve. The closing part of the three-piece ball valve is a ball, which is different from the gate valve. The following describes the working principle of the three-piece ball valve from the closing and opening of the three-piece ball valve. Let me talk about the closing part first to better distinguish the difference from the gate valve.
1. When we need to perform closing operation, we need to rotate the handwheel clockwise, the valve stem starts to descend and the ball leaves the valve seat and starts to rotate.
2. Continue to rotate, the valve stem is affected by the guide pin embedded in the spiral groove on it, so that the valve stem and the ball rotate 90 degrees at the same time.
3. When the valve is about to close, the ball has rotated 90 degrees without contact with the valve seat.
4. In the last few turns of the rotation, the angular plane at the bottom of the valve stem presses the ball so that it is pressed tightly against the valve seat to achieve a complete seal..
1. Before the valve is opened, it is in the closed position. At this time, the ball is pressed against the valve seat by the mechanical pressure of the valve stem.
2. Turn the handwheel counterclockwise, at this time the valve stem moves in the opposite direction, and the angular plane at the bottom makes the ball leave the valve seat.
3. Then the valve stem continues to lift and interacts with the guide pin in the helical groove of the valve stem to make the ball start to rotate without friction.
4. Until it is fully opened, the valve stem is lifted to the limit position, and the ball is also rotated to the fully open position. At this time, the three-piece ball valve is fully opened.