| 摘要 |
A fluid control valve, in which the usual metal stem guide bushings have been eliminated, includes a valve bonnet (30) and a packing nut (56) threadably engaging the valve bonnet (30). A valve stem (26) passes through the valve bonnet (30) and the packing nut (56) in a clearance fit so that there is no engagement therebetween. A single packing set (38) is included, having a middle virgin PTFE sealing ring (42), a carbon or glass filled PTFE male packing ring (46) on one side and a carbon or glass filled PTFE female ring on the other side. Belleville disk springs (52) may be provided intermediate the packing nut and the packing set, for supplying live loading to the packing. The packing provides sufficient stem guidance, interference fit with the valve stem (26) to enable the usual upper and lower metal guide bushings to be eliminated.
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