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.
Claims19
A two-part back cap for a plug valve having a plug value body, comprising:
- a back cap seal body having an inner end and an outer end, the inner end comprising a seal rim with an O-ring groove that supports an O-ring seal between the seal rim and the plug valve body, and the outer end comprising first and second surfaces respectively inclined towards the seal rim at different angles;
- and
- a back cap retainer nut that threadedly engages the plug valve body to retain the back cap seal body within the plug valve body, the back cap retainer nut supporting only the first surface unless the plug valve is subjected to high fluid pressures.
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 and an outer end comprising first and second surfaces inclined at different angles;
- and
- a back cap retainer nut with an inner end that supports only the first surface unless the plug valve is subjected to high fluid pressure, and threads that engage the plug valve body to retain the plug and the back cap seal body within the plug valve body.
A two-part back cap for a plug valve body, comprising:
- a back cap seal body comprising an inner end with a plug support surface that supports a valve plug in the plug valve body, a seal rim that supports at least one O-ring against an end cap seal surface of the plug valve body, and an outer end having a first surface adjacent a stud bore through the back cap seal body and a second surface continuous with the first surface, the first surface being inclined toward the seal rim at a first angle and the second surface being inclined toward the seal rim at a second angle that is greater than the first angle;
- and
- a back cap retainer nut that supports the back cap seal body and has an inner end inclined toward the seal rim at the first angle, and further having a thread for engaging the plug valve body to retain the back cap seal body and the valve plug within the plug valve body.
Dependencies are inferred from the claim text.