Liner connection
AssigneeSeal Tech Corp.
InventorFrederick W. Johnson
Life of this patent
Estimating the term…
Abstract
A connection for plain end well liner pipe and the like uses a threaded pin and box having a locking reverse angle thread profile to prevent radial separation of the pin and box due to deep well pressure and make-up pressures. The connection includes a primary internal seal structure wherein a metal-to-metal interference seal is located adjacent a thermoplastic ring seal. Separation of the interference seal due to the proximity of the thermoplastic seal is prevented by the locking thread profile. An external seal uses a metal-to-metal interference seal enhanced by a locking torque shoulder seal which acts with the thread profile to prevent radial separation of the interference seal.
Claims19
A multi-seal pin and box connection for tubular members comprising:
- (a) a multi-groove helical thread with each groove having an entrant portion equidistant with adjacent groove entrant portions and with each groove including a negative draft load flank;
- (b) a seal ring groove formed in the box portion of said connection immediately adjacent the innermost thread thereof for carrying a deformable thermoplastic seal therein such that the said pin portion's thread extends into said seal ring groove compressing said seal ring;
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- (c) a primary interference seal formed between said pin and box immediately adjacent said seal ring groove.
A multi-seal pin and box connection comprising:
- (a) a multi-groove helical thread with each groove having an entrant portion equidistant with adjacent groove portions and with each thread and groove comprising a root, a fill, a reverse angle load flank and a positive stabbing flank with said threads interfering along said root, fill, and load flank;
- (b) a seal ring groove formed in the box portion of said connection immediately adjacent the innermost thread thereof for carrying a deformable thermoplastic seal therein such that the said pin portion's thread extends into said seal ring groove compressing said seal ring with said seal ring groove having a forward surface inclined at an acute angle to the axis of said tubular member such that said forward surface forms an oblique angle with an adjacent stabbing flank;
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- (c) a primary interference seal formed between said pin and box immediately adjacent said seal ring groove.
A multi-seal pin and box connection for tubular members comprising:
- (a) cooperative multi-groove helical threads formed in said box and pin with each groove having an entrant portion equidistant from adjacent groove portions with each groove including a negative draft load flank defining a negative draft thread;
- (b) a primary internal seal formed by interference between the outer diameter of said pin and the inner diameter of said box proximal the innermost threaded engagement thereof;
- (c) a seal ring groove formed in said box intermediate said threads and said inner diameter forming said primary internal seal such that the thread of said pin extends into said seal ring groove for compressing a deformable thermoplastic ring carried therein;
- (d) an external seal formed by interference between the outer diameter of said pin and the inner diameter of said box proximal the outermost threaded engagement thereof wherein the outer diameter of said pin at said seal is greater than the inner diameter of said box at said seal;
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- (e) a torque shoulder seal formed by opposing terminal surfaces of said box and pin intermedite said external seal and the outer surface of said tubular members.
A connection for joining tubular members having one end configured as a pin and another end configured as a box, comprising:
- (a) cooperative multi-groove helical threads formed in said pin and box, and having a reverse angle load flank;
- (b) interference means for forming a primary internal seal proximal said threads;
- (c) means for confining a thermoplastic annular seal between said pin and box intermediate said threads and said interference means such that said thermoplastic annular seal is compressed by said threads immediately adjacent said primary internal seal;
- (d) ramp means for radially deflecting the terminal portion of said box to form a secondary interference seal at the junction of said pin and box whereat said pin has a larger outside diameter than the inside diameter of said box;
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- (e) shoulder means for urging said deflected portion of said box toward the axis of said tubular members and retaining said deflected portion against radial expansion.
Dependencies are inferred from the claim text.