Residual Chlorine Analyzers

Residual chlorine analyzers measure free chlorine, total chlorine or chlorine dioxide online. They are used for treated water leaving the plant, secondary supply, distribution networks, swimming pools, food and beverage rinse water and hospital wastewater disinfection.

Common principles are constant-voltage amperometric, membrane-covered polarographic and colorimetric measurement; each has its own requirements for sample flow, pH and maintenance. Outputs are usually 4–20 mA plus relays, so the analyzer can control a hypochlorite or chlorine dioxide dosing pump.

Define the measured species (free or total chlorine), range, sample pH variation, whether pH should be measured as well, and the installation (for example a flow cell). Calibrate as the manual specifies and keep the sensor and flow cell clean.