Couplings for standard A.P.I. tubings and casings and methods of assembling the same

摘要

A pipe coupling system including a modified collar (12) into which a first pipe (40) and a second pipe (30) are inserted. In a first embodiment, a ring (22) resides within the collar which can serve as a torque shoulder or a metal to metal seal. In a second embodiment, a composite element (22') is formed of three concentric rings, a first ring (41) being composed of a Teflon® like material, a second ring (44) being composed of a Torlon® or Peek® like material, and a third ring (42) composed of a Teflon® like material. The adjoining surfaces (60,61) of the rings (41,42,44) form leakage paths to relieve accumulated pressure within the collar thread voids (51). A slip on gauge (52) is disclosed for prescreening pipe to insure that it is within the tolerances required for the present system. A bucking plug (8) is disclosed for insuring that the first pipe (40) is inserted within the collar (12) to the proper depth.