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Bushing-less stem guided control valve

DC
  • US 5,791,629 A
  • Filed: 10/31/1996
  • Issued: 08/11/1998
  • Est. Priority Date: 10/31/1996
  • Status: Expired due to Term
First Claim
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1. A fluid control valve comprising:

  • a valve body having a fluid inlet, a fluid outlet, a passageway communicating therebetween, and a valve seat in said passageway for controlling the fluid flow;

    a valve bonnet mounted to the valve body and having a central bore;

    an elongated valve operating member extending through said valve bonnet central bore with a plug end for sealingly engaging said valve seat, including a lower clearance bore between said valve bonnet and said elongated valve operating member so there is no engagement therebetween;

    an elongated packing nut threadably engaging the valve bonnet, including an upper clearance bore along the entire length thereof at all times between the packing nut and the valve operating member so there is no engagement therebetween;

    at least two packing sets in said valve bonnet central bore surrounding said valve operating member, each of said packing sets formed of V-type PTFE packing rings including a PTFE sealing ring between opposite male and female filled PTFE packing rings;

    disc springs surrounding said valve operating member with a clearance along the entire length thereof at all times so there is no engagement therebetween, said disc springs mounted intermediate said packing nut and said first spacer ring and responding to said threadable engagement of said packing nut for compressing said disc springs and applying a variable packing load on said two packing sets, wherein initially with said disc springs uncompressed there is a clearance fit between said two packing sets and said valve operating member, and upon further threadably engaging the packing nut on said valve bonnet, the disc springs are compressed to apply said variable packing load on said two packing sets;

    a first spacer ring between said disc springs and one of said packing sets and a second spacer ring between said two packing sets, including a clearance between the valve operating member and each spacer ring along the entire length thereof at all times so there is no engagement therebetween; and

    said two packing sets including stabilizing and sealing means (1) for solely stabilizing and guiding the valve operating member within the valve bonnet central bore and the packing nut upper clearance bore by said two variably loaded packing sets providing a guidance fit engagement between the two loaded packing sets and the valve operating member, said guidance fit engagement between the two variably loaded packing sets and the valve operating member is solely sufficient to guide and stabilize the valve operating member from side loads applied to the valve operating member, and (2) for solely sealing the valve operating member and the valve bonnet central bore outer diameter by said two variably loaded packing sets providing a sealing fit engagement, said sealing engagement fit between the two variably loaded packing sets and the valve operating member being sufficient to provide said seals.

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