HIGHLY-TIGHT SCREW JOINT

摘要

The invention relates to building oil and gas wells and can be used in casing strings and tubings. The inventive highly-tight screw joint comprises internal and external mating elements with conical surfaces. The internal and external elements are provided withh a thread. Said thread has supporting and embedded faces. A sealing unit is made in the form of a wedge on the side of a small diameter. The sealing unit is provided on the internal and external elements. The sealing unit consists of the parts of the internal and external elements. The internal and external elements of the sealing unit are formed by conical radial and conical stop faces. The conical radial face is made at an angle of 25°-35° to the normal to the thread axis. The conical supporting surface is made at the angle of 10°-25° to the normal to thread axis. Said invention makes it possible to increase the reliability, the tightness and the strengh of the joint, to ease the assembly and disassembly thereof, to improve the abrasion resistance of the joint and to extend the service life thereof.