THREADED CONNECTION FOR PIPES Russian patent published in 2015 - IPC F16L15/04 

FIELD: construction.

SUBSTANCE: in a threaded connection for pipes, a coating having Vickers hardness of more than 310 units or equal to this value is formed in the section of the coupling thread and the inner surface of the coupling, which corresponds to the sealing section. Ratio of preload for sealing to diameter (δ/D) of the sealing section in circumferential direction of the pipe exceeds 0.002 or is equal to this value; with that, (D) is outside diameter of a nipple at the sealing point located on the outer peripheral surface of the front part of the nipple, where the outer peripheral surface contacts the inner peripheral surface of the front part of the coupling, and (δ) is a preload that is determined as a value by which outside diameter is reduced at the sealing point by crimping of the coupling when the nipple and the coupling form a threaded connection between each other.

EFFECT: invention improves a procedure for prevention of jamming between the nipple and the coupling when being connected.

4 cl, 5 dwg