TUBULAR JOINT WITH TRAPPED MID-JOINT METAL TO METAL SEAL

摘要

A joint (10) and male and female tubular element (30, 20) where the threads (70, 80) of the female and male members (20, 30) have negative load flanks (44) and have two or more radial steps axially separated one from another by a reverse angle torque shoulder (43) having one or two adjacent conical sealing surfaces (41, 42). The reverse angle torque shoulder (43) produces radial positional interference of the conical sealing surfaces (41, 42) when the male and female members (30, 20) are fully assembled and serves as a positive assembly stop. The negative load flank angle of the threads and the reverse angle torque shoulder combine to interlock the male and female members and to prevent differential radial separation of the conical sealing surfaces when the joint (10) is exposed to internal pressure, external pressure or both. Tapered threads and sealing surfaces and interference threads may advantageously be used in joint construction.