LEAKPROOF SCREWED CONNECTION OF OIL-FIELD PIPES Russian patent published in 2008 - IPC E21B17/42 F16L15/00 

FIELD: oil and gas industry.

SUBSTANCE: leakproof screwed connection of oil-field pipes includes male and female pipes with tapered threads, and sealing and stop surfaces. Sealing surfaces are provided on outer surface of male pipe end section and on inner tapered surface of female pipe, in the section between tapered thread and pipe body. Stop surfaces are provided on male pipe in the form of tapered end surface with taper angle of 5°≤β≤25° in the direction of tapered thread axis and mating tapered end surface provided on female pipe that is arranged in the section of the first tapered surface of this pipe passing to its body. Tapered thread profile has a negative angle along the supporting edge. In this case the height of male pipe's thread profile is less than the height of female pipe's thread profile, and sealing surface of male pipe's edge section at the beginning and at the end of tapered radial seal area is spherically shaped.

EFFECT: decreasing radial thread tightness value and providing additional seal of pipe string.

3 dwg