GB567162A - Electrode assembly for ph measuring systems - Google Patents

Abstract

567,162. Determining physical qualities of materials. MARCONI INSTRUMENTS, Ltd., and JACKSON, J. July 26, 1943, No. 12137. [Class 37] An electrode assembly for measuring the pH value of a fluid includes a closed electrode chamber e through which fluid to be tested is caused to flow and a second closed chamber g connected to this chamber. The fluid to be tested is led in by a pipe a through a pre-mixer b and one of the ways of a multi-way tap c to the electrode chamber e. Excess fluidflows through a constant-head tube d open to the atmosphere, which governs the rate of flow of fluid through the electrode assembly. Within the chamber e is a glass electrode f, which may have a resistance thermometer in its stem to provide for temperature compensation. At the lower part of the junction of the chambers g, e is a constriction p forming a weir. The reference half-cell or -electrode i is mounted in the side chamber g and the liquid junction is made. through a tube ending in a sintered glass disc h. The chamber g has an outlet tube k .connected by rubber tubing l to a drainage tube m, the height of which is adjustable for regulating the rate of flow of the fluid. A reservoir containing salt-bridge solution, such as saturated potassium chloride, is connected to the half-cell i. A reservoir o containing buffer solution is connected to an inlet of the multi-way tap c. For standardising the tap c is turned to close the inlet tube and empty, the contents of the chambers e, g with the exception of a small quantity which collects in the chamber gas a result of the weir. The tap c is then turned to allow buffer solution to flow - from the reservoir o to fill the electrode chamber e and to immerse the electrode h. After standardisation, the electrode chamber is again emptied and the flow of test solution is recommenced.