| 摘要 |
A gate valve 11 has a gate 21 and a valve body 13 having valve seats 33, a central chamber 25 and a flow passage 19 extending therefrom. The gate has a hole 23, and a shear element 35 mounted to at least one of the valve seats. The shear element is capable of movement in response to movement of the gate from the open position to the closed position. The gate may be linearly movable within the chamber and the shear element may be in an extended position when the gate is open and a retracted position when the gate is closed. The shear element may move relative the valve seat. The valve seats may have sealing surfaces 39 that engage the gate when the gate is in the closed position. There may be a shear pin (59, figure 7) extending through the shear element and connected to the valve seat.
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