| 摘要 |
A gate valve 40 has a body 42 having a cavity 45 and a flow passage 44 intersecting the cavity. A seat ring 50 is mounted in a counterbore pocket 54 in the body 42 at the intersection of the flow passage 44 and the cavity 45. A gate 46 is installed in the cavity 45 and has an engaging face 82 that slidingly engages the seat ring 50 while the gate is being moved between open and closed positions. The end faces 58, 72 between a seat counterbore pocket 54 and the seat ring 50 are hard coated 70, 74 and smoothly finished to provide sealing when mated. The hard coated counterbore pocket and seat ring sealing surfaces 58, 72 extend the life of the valve 40 by eliminating the need for an elastomeric seal of limited life.
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