Three-piece ball valve works as follows:

    1, open process

    1 in the closed position, the sphere by the stem of the [wiki] machinery [/ wiki] pressure role, pressed on the seat.

    2 When the handwheel counterclockwise, the stem is the reverse movement, which undocked from the bottom of the angular plane to the sphere valve seat.

    3 Stem continue to upgrade and with the stem of the guide pin screw slot interaction, so that ball began to spin without friction.

    Up to four fully open position, valve stem to upgrade to the limit position, the sphere rotated to the fully open position.

    2, close the process of

    A closed, clockwise rotation of hand wheel, valve stem began to decline and to leave the seat begins to rotate the sphere.

    2 continues to rotate hand wheel, spiral stem were embedded in its slot on the role of guide pins, so that stem and the ball while rotating 90 °.

    3 is about to shut down when the ball has been no contact with the valve seat under rotated 90 °.

    4 hand-rotation of the final laps, the bottom of the stem wedge angular plane mechanical ball to the oppression so tightly pressed on the seat to achieve complete sealing.