GB875224A - Improvements in piping systems - Google Patents

Abstract

875,224. Indicating leaks in pipes. BRISTOL AIRCRAFT Ltd. June 25, 1958 [June 25, 1957], No. 19996/57. Class 99(2). In a section of double-walled piping in which the walls are joined together at each end of the section, the inner bore carries working fluid under pressure and the outer wall is constructed to permit visual detection at a point along the length thereof of the infiltration of working fluid from the inner pipe into the space between the walls of the pipes, but not so as to permit, in the event of a crack occuring in the inner wall during normal use of the piping, the escape through the outer wall of working fluid. As shown, the walls 1, 2 of the piping are bell-mouthed at 3 and sealed by the clamping pressure of a fitting to which the piping is connected, and the outer wall has. attached thereto a nipple 4 formed with a conical end 5 and a screw-thread 6 for the attachment of pressure testing apparatus. A cap 7 screwed on to the nipple has a small hole 8 by which leakage of liquid through the inner wall is detected. In modifications, (a) the cap 7 clamps a plate against the nipple 4, the plate being of sintered metallic particles or unglazed ceramic material ; the latter may be white in colour to clearly make visible the presence of an escaped coloured liquid or may be treated with an indicator which changes colour by chemical reaction with an escaping gas, (b) the nipple contains a piston 13 carrying a sealing ring 14 and a rod 15 which passes through a hole 16 in the cap 12, leakage of gas or liquid through the inner wall forcing the piston outwardly so that the rod gives a visual indication of such leakage, and (c) the outer wall 2 is made of transparent or translucent plastic such as polythene to detect leakage of coloured gases.