US 12,258,817 B2
Thread connection for casings
Sergey Alexandrovich Rekin, Moscow (RU); Maxim Evgenievich Tyuldin, Moscow (RU); Pavel Nikolaevich Sidorenko, Taganrog (RU); and Maxim Nikolaevich Kruchkov, Taganrog (RU)
Assigned to PAO “TMK”, Moscow (RU)
Appl. No. 18/013,031
Filed by PAO “TMK”, Moscow (RU)
PCT Filed Jun. 29, 2020, PCT No. PCT/RU2020/000314
§ 371(c)(1), (2) Date Dec. 27, 2022,
PCT Pub. No. WO2022/005319, PCT Pub. Date Jan. 6, 2022.
Prior Publication US 2023/0243219 A1, Aug. 3, 2023
Int. Cl. F16L 17/04 (2006.01); E21B 17/042 (2006.01); F16L 15/06 (2006.01)
CPC E21B 17/042 (2013.01) [F16L 15/06 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A thread connection for casings comprising:
a male element (1) and female element (2) both having ends wherein, the ends both externally and internally, are produced correspondingly with tapered trapezoidal threads (3);
sealing surfaces (8) and (9) and shoulder end face surfaces (12) and (13) collectively forming an internal sealing unit, wherein the tapered trapezoidal threads (3) each is characterized with a thread turn profile having crests (6) and roots (7) both produced parallel to an axial line of the tapered trapezoidal threads (3),
said internal sealing unit is equipped with additional surfaces (10) and (11), located between said sealing surfaces (8) and (9) and said shoulder end face surfaces (12) and (13) correspondingly, wherein the additional surface (11) is produced in the form of a taper surface on the female element (2), the additional surface (10) is produced in the form of a taper surface or convex spherical surface on the male element (1), and a transition from the sealing surfaces (8) and (9) to the additional surfaces (10) and (11) are produced in the form of concave spherical surface (14) on the male element (1) and of convex spherical surface (15) on the female element (2).