| 摘要 |
The present invention pertains to a tubular connection (100) having a stabilized center-shoulder seal (104). The stabilization of the center-shoulder seal is achieved using at least one run-out section (114, 110) of thread adjacent to the center-shoulder seal configuration of each connection member. The run-out section of thread is typically used in combination with a run-in section of thread on the corresponding connection member. Preferably, the center-shoulder seal configuration of each connection member is positioned between a run-out thread section and a run-in thread section. (The corresponding connection member will comprise the corresponding sections of run-in and run-out threads, respectively, so there is an interengaging set of run-in and run-out threads). Even more preferably, in addition to the connection having one set of run-out and run-in thread sections adjacent to the center-shoulder seal, the connection has a second set of run-out and run-in threads adjacent to the exterior edges of the connection (A double run-out, run-in stabilization of the center-shoulder seal). The double set of run-out, run-in sections of thread provides the most stable connection. The most preferred center-shoulder seal design is a "locked double shoulder" design (119), wherein the cross section of the assembled center-shoulder area exhibits an interlocking double shoulder configuration. The most preferred thread profile is a single hook thread profile wherein the load flank angle is a negative angle and the stab flank angle is about zero degrees. The preferred thread profile comprises chamfered stab flanks at least at locations which will come into contact upon initial telescoping of a connection pin member into a connection box member. The thread is typically a variable width thread having a progressively increasing thread width throughout a continuous section of thread. |
