| 摘要 |
A valve formed of a body, adapted to be clamped between flanges in a pipeline, having a flow passageway therethrough defining an annular valve seat, a valve disc assembly positioned in the flow passageway and movable between a closed and an open position, the disc having a peripheral sealing surface which engages the valve seat when the valve is closed and is turned 90 degrees so that its plane is parallel to the axis of the flow passageway, when it is open. A valve stem is provided and means for axially moving the valve stem through two coaxial valve stem openings in the body. Two cam systems are provided on the valve stem. The first serves to move the valve towards or away from the valve seat as the stem moves axially. The second serves to turn the valve stem through an angle of 90 degrees due to further axial motion of the stem. The valve disc assembly is supported on the valve stem such that it can be moved in a direction perpendicular to the axis of the stem, but cannot rotate with respect to the stem.
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