GB1383637A - Electrochemical cell for quantitative analysis - Google Patents

Abstract

1383637 Electro-chemical analysis SOC CENTRALEC 18 July 1973 34190/73 Heading G1N The concentration of ions e.g. Fe<SP>++</SP> in FeCl 3 solution for chemical machining in a cell is determined by measuring the current between a pair of identical electrodes to a which is applied a constant voltage, the cell being provided with means for agitating the solution to provide a constant flow rate between the electrodes. Measuring compartment 3 of the cell is immersed in the bath of solution to be studied and a motor 2 started to drive a turbine wheel 4 to draw into compartment 3 the solution via aperture 19, along annular duct 17 through device 21, supplying turbine wheel 4, and out of the compartment 3 via duct 30. Electrodes 5, 6 each comprising a vitreous carbon cylindrical rod 12 in tubular insulating holder 12a and connected to wire 13 by mercury drop 14 have a constant voltage of 0À8V applied thereto. The current flowing is read off and knowing the temperature of the bath the ion concentration is read off from a graph of current versus concentration prepared from current V voltage curves of a number of different concentrations at a predetermined temperature, Fig. 4 (not shown). The electrodes 5, 6 may comprise a carbon rod 12 in contact via a mercury drop with a metal rod of tungsten the opposite end of which is silver welded to wire 13, Fig. 3 (not shown). Flow through cell, Fig. 5 (not shown), a section of pipe has a cell chamber containing electrodes extending through the pipe wall so that the electrodes are disposed at the axis of the pipe. Instead of a turbine wheel a convergent-divergent Venturi tube is provided to agitate the solution in the neighbourhood of the electrodes. The same cell can be used to measure different species in the same solution by switching in the appropriate inter electrode voltage.