| 摘要 |
1302104 Pipe joints; shaft couplings ARMCO STEEL CORP 30 April 1970 [5 May 1969] 20918/70 Headings F2G and F2U A joint between male and female metallic members 10, 11 comprises interengagable tapered screw threads, the male threads being of the vanishing type. A primary seal is formed between interengagable conical surfaces 12, 13 which are displaced from the screw threads. An external shoulder 14 on the male member is provided for engagement by the end 15 of the female member to prevent over-tanging, the join being undercut by between 5-10 degrees (see Fig. 4), while a further shoulder (17c), Fig. 3 (not shown), is provided within the female member to furnish a secondary seal against the end 16 of the male member. The internal shoulder may be integrally formed of the material of the female member, in which case the ends 16, (17a) (Fig. 2, not shown) may be undercut between 5-20 degrees with respect to a radius, and the tolerances of manufacture should allow a separation of not more than 0À01 inches between one shoulder and the respective end when the other shoulder and its respective end are just in contact. In this case it is not important which of the shoulders makes first contact. Alternatively the shoulder (17c) may be furnished by an insert 17 of corrosion resistant material (preferably halogenated hydrocarbon polymer) in which case the undercut must not exceed 10 degrees with respect to a radius and the end of the male member should contact the shoulder (17c) substantially before the end of the female member 15 abuts the external shoulder 14. The joint may be used when joining a male end of one pipe to the female end of a further pipe or for a "threaded and coupled" joint as shown. In the latter case the corrosion resistant material is preferably of "T" shaped crosssection and is located in a groove within the female member. The primary sealing surfaces 12, 13 may be provided with a "phonograph" finish as described in U.S.A. Specification 3,224,799. Specification 1,118,225 is referred to. |
