| 摘要 |
A valve comprises a hollow body having an inlet and an outlet, a seat ring in the outlet provides a face adapted to engage a gate, a closure mounted for movement relative to the seat ring and including a carrier having a passage therethrough in which are slidably disposed a lipped gate disc adapted to engage the seat face and block the outlet when the valve is in closed position, a pressure spring pressing the gate disc against the seat face when the valve is in closed position, and a ball transferring the reaction of the spring to the body. The closure further includes a stem extending into a port through the body, a plate engaging said tip, a helical spring engaging the plate, and a screw cap encompassing the length of the spring and threadedly engaging a threaded cuff extending from the body, the cap bearing on the spring at its end opposite from that which engages the plate, the helical spring urging the valve closure to closed position whereat a shoulder on the closure engages the seat ring, providing a travel limit stop, and retaining the closure in the body. An outlet part secured to the body over the outlet retains the seat ring in the body. The area of the disc exposed to outlet pressure is less than the area of the cross-section of the stem where it enters said port.
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