THREADED CONNECTION FOR STEEL PIPE Russian patent published in 2019 - IPC F16L15/04 

FIELD: reinforcement bars production.

SUBSTANCE: invention relates to a threaded joint for a steel pipe, which has improved sealing characteristic against internal pressure, at that, sealing characteristic against external pressure is not reduced. Threaded connection for steel pipe (1) includes nipple (10) and coupling (20). Nipple (10) includes nipple thrust (11) having nipple inner sealing surface (11a), nasal part (11b) and external thread (13). Each of external thread (13) and internal thread (23) on coupling (20) is formed by tapered thread of dovetail type. When connection is screwed, interface surface of external thread (13) and coupling surface of internal thread (23) face each other with gap provided between them. Distance D between external thread 13 and inner sealing surface 11a of nipple is 1.5 times more than pitch P of external thread 13 or more. Length L of nose part 11b is more than thread pitch of external thread 13. Difference between distance D and length L equals or is less than thread pitch of external thread (13).

EFFECT: disclosed threaded connection for steel pipe.

8 cl, 2 tbl, 5 dwg