| 摘要 |
Edge-reinforced packing is provided for steam service, with wire-reinforced secondary yarns on carriers driven along one or more diagonal tracks of a braiding machine to provide edge-reinforcing which reduces valve stem abrasion while providing sufficient resistance to high pressure, high temperature steam leakage. Wire-reinforcing only the edges of the packing minimizes the amount of reinforcing wire necessary to counteract high pressure steam and thus minimizes valve stem wear. An offset, alternating braid embodiment further reduces wire usage at the packing edges, while at the same time providing complete circumferential reinforced sealing around the valve stem. In cases where the offset braiding results in voids in the steam barrier produced by the reinforced braid, keystone-resisting technology corrects this problem. In one embodiment, the packing is a non-asbestos packing which eliminates both hardening and packing disintegration normally associated with so called "plastic-core" packings. In a further embodiment with reinforcing wire on both diagonals, the diagonal symmetry alleviates problems associated with installing the packing upside down in the stuffing box.
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