LEAKPROOF SCREWED CONNECTION OF TUBING STRING (VERSIONS) Russian patent published in 2013 - IPC E21B17/00 F16L15/00 

FIELD: oil and gas industry.

SUBSTANCE: connection contains mal and female elements with buttress conical trapezoidal threads and conical sealing surfaces and stop end surfaces at the ends of elements. Slope angle for bearing face of thread profile is from -4 up to +5°, slope angle of embedded face is 10-24°, taper ratio is 1:16. Tops and embedded faces of thread profile at connection screwing generate gaps in-between with width of 0.05-0.15 mm. Thread profiles of the male and female elements at the area of embedded face and top convergence is made rounded. At that radii of rounding are different for male and female elements. Stop end surfaces have angle of slope of 10-20° to normal line of the thread axial line. Slope angle of sealing surface of the male element is 13-18° to normal line of the thread axial line. Slope angle of sealing surface of the female element is 8-12°. At the female element at the area of thread tailing there is a circular groove (12) that forma cavity covering the first one and a half thread turns at the male element. At the tailing area of sealing surface and stop end surface there is a circular groove (14). The convergence area of sealing surface and stop end surface (14) of the female element and convergence area of sealing surface and tailing thread area of the male element are made rounded.

EFFECT: high leaktightness at impact of significant mechanical loads, wear resistance at multiple screwing and unscrewing and operation.

22 cl, 1 ex, 3 dwg