GB1503722A - Electrically insulated pipe coupling - Google Patents

Abstract

1503722 Pipe couplings BRITISH GAS CORP 8 Oct 1976 [10 Oct 1975] 41633/75 Heading F2G An electrically insulating pipe coupling comprises first and second hollow members 10, 18 each having one end adapted for coupling to a pipe, e.g. by provision of screw threads thereon, the other ends being opposed and provided with end flanges, 14, 20 with planar faces, as 22, and the members 10, 18 having equal internal diameters at the planar end faces, the member 10 having a groove 26 in the planar face accommodating an electrically insulating resilient seal, e.g. a silicone rubber 0-ring 30, and an electrically insulating annular washer 32 of mica being located between the planar faces, the coupling being held together by screws 34, screwing into the flange 20 and bearing on the flange 14 by way of a metal washer 38 and insulated therefrom by a mica washer 40, and nylon sleeves 44 surrounding each screw 34. A plastics coating 46 is provided on the internal bore and a similar coating 48 over the exposed surfaces of the flanges 14, 20. The coupling may be incorporated in a pipe elbow and as alternatives to the construction shown, the members 10, 18 may be forced together by screws of an insulating material or by a plastics coated screw-threaded ring engaging external threads on the members. The groove 26 may be provided in either of the members 10, 18 or both and the sealing ring may be of bonded asbestos.