Threaded connection

An assembly, comprising:

• a tubular body configured to be threadedly coupled to a first pipe comprising a first rim and a second pipe comprising a second rim to form a connection, the tubular body comprising a first internal thread, a second internal thread, and an inwardly-projecting annular shoulder residing between the first internal thread and the second internal thread, the inwardly-projecting annular shoulder comprising two bearing surfaces facing away from each other and each bearing, with the connection formed, against a respective one of the first and second rims;
• wherein each of the first and second internal threads comprise a root of constant diameter exclusive of at least a last root of each of the first and second internal threads;
• and
• each of the first and second internal threads comprises a width that increases from the inwardly-projecting annular shoulder to a last thread of the first and second internal threads, the width increasing uniformly across a length of the first and second internal threads.

A method, comprising:

• connecting a first pipe to a collar, the first pipe comprising a first external thread and a first rim, the collar comprising a first internal thread, a second internal thread, and an inwardly-projecting annular shoulder residing between the first internal thread and the second internal thread and comprising two bearing surfaces facing away from each other, wherein connecting the first pipe to the collar comprises threadedly coupling the first external thread to the first internal thread such that a bearing surface of the first rim forms, with one of the two bearing surfaces of the shoulder, a first seal;
• and
• connecting a second pipe to the collar, the second pipe comprising a second external thread and a second rim, wherein connecting the second pipe to the collar comprises threadedly coupling the second external thread to the second internal thread of the collar such that a bearing surface of the second rim forms, with the other one of the two bearing surfaces of the shoulder, a second seal;
• wherein each of the first and second external threads comprise a crest of constant diameter along a length of the first and second external threads exclusive of at least one thread of the first external thread and at least one thread of the second external thread, and connecting the first pipe to the collar comprises threadedly coupling the first pipe with the collar until the one thread engages the collar;
• and
• each of the first and second external threads comprises a last thread opposite the respective rims of the first and second pipes, each last thread defining, in cross section, a height greater than a height of a rest of the first and second external threads.

A pipe assembly, comprising:

• a first pipe comprising a first external thread and a first rim comprising a bearing surface;
• a second pipe comprising a second external thread and a second rim comprising a bearing surface;
• and
• a collar configured to be threadedly coupled to the first pipe and the second pipe to form a threaded connection, the collar comprising a first internal thread corresponding with and configured to be threadedly coupled to the first external thread, and a second internal thread corresponding with and configured to be threadedly coupled to the second external thread, the collar comprising an inwardly-projecting annular shoulder residing between the first internal thread and the second internal thread, the shoulder comprising two bearing surfaces facing away from each other and each bearing, with the threaded connection formed, against a respective one of the bearing surfaces of the first and second rims;
• wherein the one thread of the first external thread comprises a last thread of the first external thread, and the one thread of the second external thread comprises a last thread of the second external thread, the last threads opposite the respective rims of the first and second pipes, each last thread defining, in cross section, a height greater than a height of a rest of the first and second external threads;
• and
• wherein the first and second external threads comprise a crest of constant diameter along a length of the first and second external threads up to the last thread.

A pipe assembly, comprising:

• a first pipe comprising a first external thread and a first rim comprising a bearing surface;
• a second pipe comprising a second external thread and a second rim comprising a bearing surface;
• and
• a collar configured to be threadedly coupled to the first pipe and the second pipe to form a threaded connection, the collar comprising a first internal thread corresponding with and configured to be threadedly coupled to the first external thread, and a second internal thread corresponding with and configured to be threadedly coupled to the second external thread, the collar comprising an inwardly-projecting annular shoulder residing between the first internal thread and the second internal thread, the shoulder comprising two bearing surfaces facing away from each other and each bearing, with the threaded connection formed, against a respective one of the bearing surfaces of the first and second rims;
• wherein each bearing surface of the shoulder comprises an internal seal ring configured to bear against and form, with the threaded connection formed, a seal with a respective one of the first and second rims, the internal seal rings forming a dual seal with the respective rims;
• wherein the inwardly-projected shoulder defines, in cross-sectional side view, a tapered surface and each of the internal seal rings comprises a trapezoidal cross-section defining a leg side tapered to correspond with the tapered surface of the inwardly-projected shoulder;
• and
• each of the first and second external threads comprises a last thread opposite the respective rims of the first and second pipes, each last thread defining, in cross section, a height greater than a height of a rest of the first and second external threads.

A pipe assembly, comprising:

• a first pipe comprising a first external thread and a first rim comprising a bearing surface;
• a second pipe comprising a second external thread and a second rim comprising a bearing surface;
• and
• a collar configured to be threadedly coupled to the first pipe and the second pipe to form a threaded connection, the collar comprising a first internal thread corresponding with and configured to be threadedly coupled to the first external thread, and a second internal thread corresponding with and configured to be threadedly coupled to the second external thread, the collar comprising an inwardly-projecting annular shoulder residing between the first internal thread and the second internal thread, the shoulder comprising two bearing surfaces facing away from each other and each bearing, with the threaded connection formed, against a respective one of the bearing surfaces of the first and second rims;
• wherein each of the first and second external threads comprises a crest of constant diameter along a length of the first and second external threads exclusive of at least one thread of the first external thread and at least one thread of the second external thread;
• and
• each of the first and second threads comprises a width that increases from the respective rim to a last thread of the first and second threads.