Special round thread pipe coupling

Abstract

The invention relates to a special round thread highly-torque-resistant oil pipe coupling, which comprises a hoop and a pipe which are in threaded connection. The form of the thread belongs to a special round thread with an arc-shaped tooth crest and an arc-shaped tooth bottom, and the flank angle of a guiding face of the thread is different from that of a bearing face. A middle cylindrical surface is arranged on the inner wall of the hoop, and metal sealing structures are arranged between the two end surfaces of the middle cylindrical surface and the ends of the pipe respectively. Each metal sealing structure comprises an inner sealing face and an outer sealing face. The inner sealing face includes an inner cone chamfered face arranged between the end face of the middle cylindrical surface and the end of the internal thread of the hoop, an inner conical face and a transition conical face. The end face of the middle cylindrical surface is inclined outwards to form an inner end chamfer. The outer sealing face includes an outer conical face arranged on the outer wall of the end of the pipe and an outer cone chamfered face. The end face of the end of the pipe is inclined inwards to form an outer end chamfer. The special round thread pipe coupling is provided with the dissymmetrical special round thread, is provided with the double arc type metal sealing structures, and is high in intensity, fine in sealing performance, and high in torque resistance and bending resistance.

Description

technical field [0001] The invention relates to an oil well pipe thread joint used in the petroleum industry, in particular to a special round thread pipe joint. Background technique [0002] The oil and casing in the oil well pipe industry is mainly connected by threaded joints to form an oil and casing string with a length of several thousand meters. Among them, the strength requirements, sealing performance, tensile load and torque resistance of the threaded joint connection Higher requirements. [0003] At present, the structure of the existing oil-casing round thread connection is basically the API (American Petroleum Institute) standard round thread. The technology is relatively mature, but the use effect is not ideal. This kind of standard round threaded joint has poor sealing surface performance and weak bending resistance, which often leads to quality accidents such as leakage, breakage, and slippage at the threaded joint. Contents of the invention [0004] In v...

AI Technical Summary

Problems solved by technology

[0003] At present, the existing oil casing round thread connection structure is basically API (American Petroleum Institute) standard round thread, the technology is relatively mature, but the use effect is not ideal

This kind of standard round thread joint has poor sealing surface performance and weak bending resistance, which often leads to quality accidents such as leakage, breakage, and slippage at the threaded joints.

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