Two-part back cap for a plug valve and plug valves incorporating same
AssigneeStinger Wellhead Protection, Inc.
InventorDanny Lee Artherholt
Life of this patent
Estimating the term…
Abstract
A two-part back cap for a plug valve includes a back cap seal body and a back cap retainer nut. The back cap retainer nut secures the back cap seal body within the plug valve and securely supports the back cap seal body. A gap between an outer periphery of the back cap retainer nut and the back cap seal body permits the back cap seal body to flex and expand with a plug valve body of the plug valve. This ensures that the back cap seals are not stressed and a longer service life results.
Claims20
A two-part back cap for a plug valve body, comprising:
- a back cap seal body having an inner end and an outer end, the inner end comprising a plug support surface for supporting a plug in the plug valve body and a seal rim for sealing against the plug valve body, and the outer end comprising an outer surface;
- and
- a back cap retainer nut that retains the back cap seal body in the plug valve body and has an inner surface that cooperates with the outer surface of the back cap seal body to permit the back cap seal body to flex under fluid pressure until the outer surface of the back cap seal body is in full metal-to-metal contact with the inner surface of the back cap retainer nut.
A plug valve, comprising:
- a back cap seal body having an inner end with a plug support surface for supporting a plug received in a plug valve body of the plug valve, a seal rim for providing a fluid seal between the back cap seal body and the plug valve body, and an outer end comprising an outer surface;
- and
- a back cap retainer nut with threads that engage the plug valve body to retain the plug and the back cap seal body within the plug valve body, and an inner surface that cooperates with the outer surface of the back cap seal body to permit the back seal body to flex until a fluid pressure within the plug valve is high enough to force the outer surface of the back cap seal body into full metal-to-metal contact with the inner surface of the back cap retainer nut.
A two-part back cap for a plug valve body, comprising:
- a back cap seal body having an inner end with a valve plug support surface, a seal rim that supports at least one fluid seal against an end cap seal surface of the plug valve body, and an outer end with an outer surface;
- and
- a back cap retainer nut having a thread that engages a thread of the plug valve body to retain the back cap seal body and the valve plug within the plug valve body, the back cap retainer nut further having an inner end that cooperates with the outer surface of the back cap seal body to permit the back cap seal body to flex under fluid pressure until the outer surface of the back cap seal body is forced by the fluid pressure into complete metal-to-metal contact with the inner end of the back cap retainer nut.
Dependencies are inferred from the claim text.