Wedgethread pipe connection

Abstract

A threaded pipe connection assembled using a thread lubricant, having a female thread (2) and a male thread (1) formed with a tapered fitting wedge thread, the female thread has a crest (21), a root (8) , embedded thread flank (4) and load thread flank (6), the male thread has crest (7), tooth root (20), embedded thread flank (3) and load thread flank (5), in An included angle (35) measured in the gap between the flanks of the thread having a first axial crest width at (17) and a second axial crest width at (54) crest width, said first and second crest widths being arranged one thread turn apart, the dimension of the first crest width (17) being calculated from the first radius (18) and the dimension of the second crest width (54) Calculated from the second radius (55), the dimension is a bridging thickness of the widest gap width that lubricant can seal between mating threads, and the dimension is a minimum thickness that lubricant can compress between mating threads, including: The first crest radius minus the second crest radius is a first value; the first crest width minus the second crest width is a second value, and the first value is divided by The second value is a change ratio; the change ratio is not greater than a ratio obtained by dividing the bridging thickness dimension by the minimum thickness dimension.

Description

technical field [0001] Threading pipe joints together for conveying fluids is a very old technology that has been developed over hundreds of years to meet periodic needs for stronger and better sealed pipe connections. The performance requirements of pipe connections still vary widely, for example from domestic pipes that contain fluid pressures of less than 80 psi and virtually no mechanical loads, to oil well pipes that need to maintain 15,000 psi air pressure while withstanding extreme mechanical loads and large temperature fluctuations. The use of pipe threads to connect structural members is also old technology. [0002] Due to the historical fragility of threaded pipe connections and their tendency to loosen, leak and / or break, their use in factories and refineries has been limited by industry regulations to very small pipe diameters and low pressures. However, since there are no suitable alternatives for the very limited borehole sizes drilled for oil & gas wells, thre...

AI Technical Summary

Problems solved by technology

Subsequent assembly torque applied to the connection in the test laboratory after a leak can temporarily reseal the thread flank gap, but cannot close the crest gap leak because the crest gap does not contain fluid lubricant

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