Abstract: To regulate and monitor material concentrations, e.g., sodium chlorite or hydrogen peroxide, measuring cells are employed in which these substances are reacted to completion with another substance, e.g., sulfur dioxide, in an exothermal reaction. The resulting temperature rise is then a measure for the concentration. A simple measuring cell includes a pipe section provided at both ends with mounting devices for mounting in the delivery line conveying the reaction medium. There is mounted in this pipe section a U-shaped pipe section which is open at both ends and has a smaller diameter, and whose two arms extend into the pipe section with a larger diameter. The center section of, and parallel to, is located outside of the larger pipe and is provided with a thermal insulation, a supply line for the reacting substance, and a temperature sensor.

Abstract: To regulate and monitor material concentrations, e.g., sodium chlorite or hydrogen peroxide, measuring cells are used in which these substances react to completion with another substance, e.g, sulfur dioxide, in an exothermal reaction. The resulting temperature rise is then a measure of the concentration. A measuring cell comprises a pipe section provided at both ends with mounting devices for installation in the delivery line transporting the reaction medium. Within this pipe section there is positioned axially a smaller diameter pipe section which is open at both ends, into one open end of which projects the supply line for the reacting substance and at the other end of which a temperature sensor is installed.