| 摘要 |
A vertically positioned valve body having a valve seat positioned coaxially in the body in a horizontal plane. A valve element positioned upstream of the seat and axially movable in the body. The cross-sectional area of the valve element is approximately one-half of the cross-sectional area of the body around the valve element. A plurality of diametrically opposed piston and cylinder assemblies raise the valve element away from the valve seat and allow the valve element to seat by gravity and fluid flow. Guide means are provided between the valve element and the body for guiding the valve element. A sealing valve and seat are positioned upstream of the valve seat about each of the assemblies for sealing off the assemblies when the valve is closed.
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