GB708263A - Improvements in joints between tubular parts - Google Patents

Abstract

708,263. Pipe joints. METROPOLITANVICKERS ELECTRICAL CO., Ltd. Feb. 19, 1952 [March 19, 1951], No. 6537/51. Class 99 (1). In a bolted, flanged joint between pipes of different coefficients of thermal expansion, such as between a ferritic steel pipe and coupling member 1, 2 and an austenitic steel pipe and coupling member 6, 7, the member 2 has a spigot portion 3 engaging an annular recess 8 in the member 7, the dimensions of spigot and recess being such that fluid-tightness is obtained by pressure contact of the recess wall 13 with the spigot at the normal working temperature due to differential expansion of the parts. The dimensions may be such that the inner recess wall 14 is in pressure contact with the spigot when the pipes are cold. The joint may be secured by loose flanges 5, 10 and bolts 11, all of ferritic steel. The flange 10 may be separated from the austenitic steel member 7 by a flexible ring or sleeve 16 which has rounded ends engaging similar recesses in the flange and member, and has alternating slots 17 around its circumference. The spigot 3 may be partially shielded from the hot gases by an annular extension 15 of the member 7. The clearance space between them may have spaced rings to provide a number of stagnant air spaces. The base of the recess 8 may have packing 12 in the form of alternate wound layers of metallic tape and asbestos. The loose flanges may be dispensed with, the bolts having direct engagement with flanges integral with the members 2, 7. The recess 8 in this instance is without packing, the end of the spigot being rounded to seat in the similarly shaped base of the recess.