METHOD AND MECHANISM FOR EVALUATING CONCENTRATION OF RESIDUAL HALOGEN

PROBLEM TO BE SOLVED: To evaluate the concentration of residual halogen by measuring the potential difference before and after the decomposition process of hypohalogenoacid in residual free halogen contained in an objective liquid thereby evaluating the concentration of hypohalogenoacid easily. SOLUTION: A decomposition region 2 for introducing a liquid to be evaluated is formed in a glass case 1 for decomposition and a decomposition means for hypohalogenoacid, i.e., powder active carbon (about 5g), is contained. A liquid to be evaluated is then introduced, at a specified flow velocity, into the glass case 1 for decomposition through a metering pump P and brought into contact with the powder active carbon in order to decompose hypohalogenoacid contained in the liquid to be evaluated. Two glass cases 4 for arranging a platinum electrode 3 are then disposed in front and rear of the glass case 1 for decomposition and the potential difference across the decomposition region 2 is measured and recorded by a current measuring/recording unit V. It is compared with a potential difference before and after decomposition of hypohalogenoacid contained in the reference liquid having a predetermined concentration of hypohalogenoacid thus evaluating the concentration of hypohalogenoacid, and thereby, the concentration of residual halogen.