COUPLING FOR OIL AND GAS FIELD PIPES

摘要

A gas- and oil-field pipe joint comprises a female part formed with a frustoconical internal thread and a male part formed with a complementary frustoconical external thread and screwable into the female part with both parts centered on a common axis. The female part further is formed centered on the axis with a frustoconical inner surface axially inward from the internal screwthread and with a frustoconical shoulder surface extending radially inward from the axially inner end of the inner surface. The male part is formed centered on the axis with a barrel portion having an ellipsoidal barrel surface engageable radially with the inner surface and with a frustoconical end surface engageable axially with the shoulder surface of the female part. The barrel portion is formed with a central frustoconical surface portion substantially complementary to the inner surface, and the end surface and the shoulder surface extend spacedly parallel to each other when the parts are threaded together with the frustoconical surface portion in contact with the inner surface but without substantial deformation of either of the parts.