THREADED CONNECTION FOR STEEL PIPES Russian patent published in 2021 - IPC F16L15/04 

FIELD: threaded connections.

SUBSTANCE: invention relates to a threaded connection with good sealing against internal and external pressure, while preventing scuffing. Threaded joint 1 comprises a nipple 10 and a sleeve 20. The nipple 10 comprises a nipple protrusion 11, a metal nipple seal 13 and a cylindrical inner machined surface 14. The metal nipple seal 13 comprises a tapered nipple seal surface 16 and a rounded nipple seal surface 17. The sleeve 20 comprises a metallic sleeve seal 22 parallel to the tapered surface 16 of the pin seal. The metal seal 13 of the pin hermetically contacts the metal seal 22 of the box at the seal point SP. The threaded connection satisfies the following expressions (1) and (2): L>Lm>Ls (1) and tb/tp>1.6 (2), where L is the length of the pin protrusion 11; Lm is the distance between the end AP of the pin and the end point of the cylindrical inner machined surface 14; Ls is the distance between the end AP of the nipple 10 and the sealing point SP; tb is the wall thickness of the sleeve 20 as measured at the seal point SP when the joint is screwed; and tp is the wall thickness of the pin 10 as measured at the seal point SP.

EFFECT: threaded connection improvement.

8 cl, 13 dwg, 1 tbl