Patent EA-003840-B1 (EA)
Title: Tubular threaded joint with reinforced stop
Inventor: SCHES CELINE
IPC: F16L15/04
Filed: 2001-06-18
Abstract: 1) A tubular threaded connection comprising a threaded male element (11) at the end of a first tubular component (10) and a female threaded element (21) at the end of a second tubular component (20), the threaded male element being provided with a male threading (12) and ending in a male lip (18) which comprises firstly an external peripheral surface on which a male sealing surface (13) is formed, secondly a male annular abutting surface (16,14), oriented substantially transversely, located near and connected to said male sealing surface and constituted by the front surface of the free end of the male threaded element, and thirdly an internal peripheral surface (17), the female threaded element comprising, so as to co-operate with the corresponding means of the male threaded element, a female threading (22), an internal peripheral surface on which a female sealing surface (23) is formed, and a female shoulder having on the one hand a female annular abutting surface (26) oriented substantially transversely, located near and connected to said female sealing surface, and on the other hand defining a female annular shoulder zone (24) which is subjected to axial compressive loads when said male abutting surface (16) bears against said female abutting surface (26), the male threading being screwed into the female threading until said male abutting surface bears against said female abutting surface, said male sealing surface then radially interfering with said female sealing surface, characterized in that the female annular shoulder zone (24) comprises an internal peripheral surface (27), the internal diameter of which at least in close proximity to said female abutting surface (26) is smaller (IDB) than the diameter (IDp) of the internal peripheral surface (17) of the male lip (18), the ratio R of these two diameters (IDB-IDP) being less than 1 but more than or equal to 0.9. 2) A tubular threaded connection according to claim 1, characterized in that the ratio R satisfies the following relationship: in which S is equal to the ratio between the diameter (ODA) of the external edge of said male abutting surface (16) and the internal diameter (IDP) of the male lip (18). 3) A tubular threaded connection according to claim 2, characterized in that the ratio R substantially equal to 4) A tubular threaded connection according to any of claims 1 to 3, characterized in that the internal peripheral surface (27) of the female shoulder has a minimum diameter (IDB) at a point (D) where said internal peripheral surface (27) intercepts a tapered surface of maximum shearing (32), coaxial with the female threaded element, having a vertex half-angle of 45 degree , wherein the diameter in the female shoulder zone (24) decreases as the distance increases from said female abutting surface (26) and passes through the external edge (A) of said female abutting surface (26). 5) A tubular threaded connection according to any of claims 1 to 4, characterized in that the diameter of the internal peripheral surface (27) of the female shoulder at its end (B) on the side of said female abutting surface (26) is substantially equal to the internal diameter (IDP) of the internal peripheral surface (17) of the male lip (18). 6) A tubular threaded connection according to claim 5, characterized in that the internal peripheral surface (27) of the female shoulder comprises a first portion termed the transition portion (29, 39) the internal diameter of which gradually decreases from said female abutting surface (26), and a second cylindrical portion (30) with a minimum internal diameter (IDB). 7) A tubular threaded connection according to claims 4 and 6 taken together, characterized in that the transition portions (29, 39) and the cylindrical portion (30) of the internal peripheral surface (27) of the female shoulder join at a point (C) termed the junction point which is located substantially half-way axially between the end (B) of said transition portion on the side of the female abutting surface (26) and the point of intersection (D) of the internal peripheral surface (27) of the female shoulder with the tapered surface of maximum shearing (32). 8) A tubular threaded connection according to claim 6 or 7, characterized in that said transition portion of the internal peripheral surface (27) of the female shoulder comprises a tapered surface (29) which is coaxial with the female threaded element and has a vertex half-angle in the range 15 degree to 45 degree 9) A tubular threaded connection according to claim 6 or 7, characterized in that said transition portion of the internal peripheral surface (27) of the female shoulder comprises a tapered surface (29) which is coaxial with the female threaded element and has a vertex half-angle in the range 30 degree to 45 degree . 10) A tubular threaded connection according to claim 6 or 7, characterized in that said transition portion of the internal peripheral surface (27) of the female shoulder comprises at least one toric surface (39) which is coaxial with the female threaded element. 11) A tubular threaded connection according to claim 10, characterized in that said transition portion of the internal peripheral surface (27) of the female shoulder comprises a toric surface (39), wherein the tangent at its end on the side of said female abutting surface (26) forms an angle in the range 15 degree to 45 degree with the axis (XX) of the threaded connection. 12) A tubular threaded connection according to claim 10 or 11, characterized in that said transition portion of the internal peripheral surface (27) of the female shoulder comprises a toric surface (39) which is tangential at its end opposite said female abutting surface (26) to the cylindrical portion (30) of the internal peripheral surface (27) of the female shoulder. 13) A tubular threaded connection according to any of claims 1 to 12, characterized in that said female and male abutting surfaces (16, 26) form reverse abutting surfaces with a negative angle with respect to the axis (XX) of the threaded elements the dimension of which is 20 degree or less.