Strong oxidizing agent (ClO2 used for bleaching cellulose and textiles and for sterilizing drinking water (drinking water treatment). Produced right where needed in the form of an aqueous solution whose concentration, 0..10 g/l, is accessible to photometric measurement by the absorption principle.
SIGRIST absorption instruments monitor the production process continuously with a wavelength of 436 nm, which does not pick up the frequently present chlorine. Possible errors caused by contamination of flow cell windows or the presence of solids are eliminated by using turbidity compensation.