Chlorine Sensors & Transmitters

Chlorine Sensors & Transmitters

Chlorine and disinfection sensors measure oxidants used to control microbiological risk in water systems, including free chlorine, total chlorine, chlorine dioxide, and related oxidants such as ozone and free bromine. A complete measurement point typically includes the sensor, a transmitter, and an installation method suited to the process (submersion in channels/basins or mounting in flow assemblies).

Continuous disinfection monitoring supports consistent microbial control while minimizing the risks of overfeed. Systematic disinfection is often legally required, but excessive dosing can be hazardous and can accelerate corrosion or create downstream process issues; real-time measurement enables tight control of residuals rather than relying on periodic testing.

Many disinfection sensors operate on an amperometric principle using a membrane-covered measuring cell. The target species diffuses through the membrane and is reduced at the working electrode; the resulting current is proportional to concentration. For free chlorine, the measurable fraction depends on pH, and compensation can be achieved by including pH measurement in the flow assembly and applying transmitter-based correction. Total chlorine measurement accounts for free chlorine and chloramines, supporting a more complete view of residual disinfectant behavior.

Applications vary by disinfectant choice: free chlorine is widely used for drinking water, hygienic bottling/packaging water, and pool dosing; chlorine dioxide is favored where lower corrosivity and broad pH independence are important (e.g., cooling systems, certain wash waters, and desalination pretreatment); total chlorine is commonly used to track residual disinfectants in wastewater effluent and reuse; bromine is used in seawater contexts; ozone is applied for pretreatment and disinfection in water processes.

Selection emphasizes the disinfectant chemistry, expected range, and installation environment (open channel vs. controlled flow cell), along with maintenance practices appropriate to membrane and electrolyte systems. Modular measurement architectures also support multiparameter expansion and compact pre-engineered panels that integrate sensor, transmitter, assembly, and hydraulic components into a single, standardized measurement package.

George E. Booth Co., an exclusive authorized representative of sales and service for Endress+Hauser.