GB806928A - Improvements in or relating to methods and devices for testing for the presence of water in suspension in other liquids - Google Patents

Abstract

<PICT:0806928/III/1> The presence of small amounts of water suspended in fluids, e.g. aviation fuels, is detected by bringing the liquid into contact with a water-soluble powder, which changes colour, and then with a water-absorptive medium. The preferred form consists of a filter paper coated on the up-stream side with a water-soluble dye, ferric thiocyanate, or a mixture of salts developing a colour, e.g. prussian blue. Preferably the impregnated filter paper is mounted in a transparent capsule, and included in a by-pass circuit attached to the fuel supply pipe. A suitable capsule comprises two parts 1, 2, Fig. 1, made of methyl methacrylate, which may be screwed together with the sheet of filter paper 10 inserted between them, at its periphery, which is not affected by the colour change. The coating 10a on the filter paper may be a powdered mixture of ferrous ammonium sulphate and potassium ferricyanide, or ferric alum and potassium ferrocyanide. A small amount of citric or tartaric acid may be included, if necessary, to develop the colour. The assembly may be fitted to a hypodermic graduated syringe, and a measured quantity of the liquid drawn through the filter paper. Alternatively untreated filter paper or a cotton wool plug may be used in conjunction with a capsule containing the salts placed upstream thereto. The inorganic salts may be replaced by dyestuffs, e.g. crystal violet, auramine, rhodamine or magenta.