GB412446A - Improvements in or relating to well pipe joints - Google Patents

Abstract

412,446. Pipe joints. HYDRIL CO., 714, West 10th Street, Los Angeles, U.S.A. Sept. 7, 1933, No. 24835. Convention date, July 17. [Class 99 (i).] In a screw - threaded joint for well pipes, the spigot 12 and socket 10 have a two-step thread and three pairs of interengaging surfaces or shoulders, the clearances between which are so arranged that the internal surfaces 18, 39 are first engaged, the external shoulders 28, 42 are engaged next and the intermediate shoulders 20, 34 are the last to engage. The clearance between the shoulders 28, 42 is such that they are engaged before the socket is stressed beyond the elastic limit. The end of the spigot is tapered at 39 engaging the similarly tapered surface 18, and the end of the socket is bevelled at 28 and engages in a recessed shoulder in the spigot having a face 42 parallel to the face 28. The shoulders 20, 34 have radial seating faces and are preferably located between the stepped threads 32, 33. The minor diameter of thread 32 is greater than the major diameter of thread 33. The sum of the cross-sectional areas of spigot and socket at B and D is at least as great as the area of the socket at A or of the spigot at C. The area at A or C is greater than half the area at N.