A tube connection for connection to a tube includes: a body having a through hole with a central axis, a first end, a second end, and an internal thread arranged close to the first end and coaxial with the central axis. The internal thread has a constant pitch diameter. A maximum diameter of the internal thread increases in an axial direction from the first end towards the second end. A minimum diameter of the internal thread decreases in the axial direction from the first end towards the second end.

A tube connection for connection to a tube includes: a body having a through hole with a central axis, a first end, a second end, and an internal thread arranged close to the first end and coaxial with the central axis. The internal thread has a constant pitch diameter. A maximum diameter of the internal thread increases in an axial direction from the first end towards the second end. A minimum diameter of the internal thread decreases in the axial direction from the first end towards the second end.

A cap is described for connection to a medical connector, the cap includes a housing having a top wall and sidewall forming a first cavity, and a removable or integrally formed protrusion. The protrusion includes an inner thread on an inner surface, the inner thread being sufficient to interlock with a mating feature of a female needleless connector. The inner surface of the protrusion defines a second cavity. The protrusion includes an outer thread on an outer surface, the outer thread being sufficient to interlock with a mating feature of a male needleless connector. The second cavity configured to define a chamber to contain an absorbent material and disinfectant or antimicrobial agent. The cap may also include a peel seal and/or septum to prevent the disinfectant or the antimicrobial agent from exiting the second cavity. An exterior sidewall surface of the housing may include a plurality of grip members.

A cap is described for connection to a medical connector, the cap includes a housing having a top wall and sidewall forming a first cavity, and a removable or integrally formed protrusion. The protrusion includes an inner thread on an inner surface, the inner thread being sufficient to interlock with a mating feature of a female needleless connector. The inner surface of the protrusion defines a second cavity. The protrusion includes an outer thread on an outer surface, the outer thread being sufficient to interlock with a mating feature of a male needleless connector. The second cavity configured to define a chamber to contain an absorbent material and disinfectant or antimicrobial agent. The cap may also include a peel seal and/or septum to prevent the disinfectant or the antimicrobial agent from exiting the second cavity. An exterior sidewall surface of the housing may include a plurality of grip members.

In a threaded connection of a two-step thread construction including intermediate shoulder surfaces, a break is prevented near the intermediate critical cross sections upon application of a tensile load, and the intermediate shoulder surfaces are easier to create, thus improving productivity. The outer periphery portion of a pin located between an intermediate shoulder surface of the pin and a second male thread is provided with a circumferential groove including a curved surface smoothly contiguous to the intermediate shoulder surface, thereby mitigating plastic strains generated near the pin intermediate critical cross section PICCS. The inner periphery portion of a box located between an intermediate shoulder surface of the box and a first female thread is provided with a circumferential groove including a curved surface smoothly contiguous to the intermediate shoulder surface, thereby mitigating plastic strains generated near a box intermediate critical cross section BICCS.

Provided is a threaded pipe having a pin member connecting to a box member. The pin member contains wedge-shaped pin threads that extends in a helical direction around the outside surface of its pipe end. The pin member is tapered to result in an increasing diameter of the pin threads away from the front end of its pipe. The box member contains a wedge-shaped box thread that stretches in a helical direction around the inside surface of its pipe end. The box member is tapered to result in a decreasing diameter of the box threads away from the front end of its pipe. The pin crest of the pin member increases in width along the pin thread and the box root of the box thread decreases in width along the box thread. When assembled together, the pin thread crest increases in width at a different rate than the box thread root increase in width.

Provided is a threaded pipe having a pin member connecting to a box member. The pin member contains wedge-shaped pin threads that extends in a helical direction around the outside surface of its pipe end. The pin member is tapered to result in an increasing diameter of the pin threads away from the front end of its pipe. The box member contains a wedge-shaped box thread that stretches in a helical direction around the inside surface of its pipe end. The box member is tapered to result in a decreasing diameter of the box threads away from the front end of its pipe. The pin crest of the pin member increases in width along the pin thread and the box root of the box thread decreases in width along the box thread. When assembled together, the pin thread crest increases in width at a different rate than the box thread root increase in width.

A non-frustoconical coupling provides a mechanical connection used in fluid transport for hydrocarbon recovery operations.

A non-frustoconical coupling provides a mechanical connection used in fluid transport for hydrocarbon recovery operations.

Aspects of the disclosure describe a non-frustoconical coupling used in connections for tubulars in hydrocarbon recovery operations.