GB824833A - Electrically-conductive spigot and socket joints for pipes, couplings and fittings and gaskets therefor - Google Patents

Abstract

824,833. Joint-making packing. AMERICAN CAST IRON PIPE CO. March 18, 1958 [Oct. 7, 1957], No. 8623/58. Class 122 (3). [Also in Groups XXVIII and XXXVI] A gasket 13, Figs. 1 and 2, for a socket-andspigot-type pipe joint 12, 11 or other coupling is formed from a compressible electrically non- ductive material and is provided with at least one electrically-conductive member 35 extending through the gasket and having portions 36 adapted to make contact with the socket 12 and spigot 11 of the joint and so permit the flow of electric current between connected lengths of pipe. The gasket 13 may be of moulded rubber, preferably formed in two portions 13a, 13b of different degrees of hardness integrally connected on a plane 34. The outer peripheral surface of the portion 13a is formed with a locating shoulder 31 which, together with the remaining surfaces 29, 30, 32, 33 of the gasket, abut correspondingly-shaped surfaces formed in a cavity 14 provided in the socket 12, the cavity being of greater axial length than that of the gasket. The inner peripheral surfaces 27, 28 of both portions 13a, 13b are inclined, the surface 27 being at a steeper angle than the surface 28, and, when the spigot 11 is entered into the gasket, the rubber is compressed until, after the complete insertion of the spigot, the cavity 14 is completely filled. The external surfaces, especially the end face 25 and inclined surface 27, may be reinforced with fabric. In operation, fluid pressure in the pipes forces the softer portion 13b into contact with the spigot and socket surfaces and continued pressure is transmitted to the harder portion 13a thereby causing the tapered face 29 thereon to be forced into greater contact with its seating. In the modifications shown in Figs. 5 and 6 the gaskets 43, 57, which are both formed from uniform hardness rubber, have, respectively, substantially rounded body portions 45, 59 replacing the tapered portion 13b. The outer peripheral contours of the gaskets, which include locating shoulder portions 48, 61, mate with correspondingly-shaped surfaces formed in the cavity provided in the socket of their respective joints. A number of conductive members 50, 63 are spaced around the gaskets.