ORP Sensors & Transmitters

ORP Sensors & Transmitters

ORP (oxidation-reduction potential) measurement uses sensors and transmitters to track the redox potential of aqueous media as a millivolt signal. ORP is a sum parameter that reflects the overall tendency of a solution to oxidize or reduce, making it valuable for trend monitoring and endpoint control even when individual species are not resolved.

An ORP probe typically uses a noble metal measuring electrode paired with a stable reference system (commonly Ag/AgCl). Electrode material selection is process-dependent: gold electrodes are associated with oxidation-focused applications such as cyanide oxidation or ozone-related measurements, while platinum is commonly selected for reduction-oriented duties such as chromate reduction or chlorine dosing control. Junction/diaphragm and reference design are chosen to balance response, stability, and fouling resistance.

ORP monitoring provides rapid feedback on disinfection effectiveness, detoxification progress, and oxidation/reduction reaction completeness. It enables tighter control of reagent dosing, reduces the risk of over-treatment, and supports stable operation in processes where redox state is a key quality or safety variable.

Typical applications include disinfection monitoring in drinking water and pools, aeration and process control in wastewater treatment, electroplating bath detoxification, and redox management in chemical processes. Flue gas scrubbing and other environmental treatment processes also use ORP as a practical control input where reaction chemistry varies with load.

Successful installations prioritize electrode selection, stable reference performance, and appropriate mechanical design - immersion, flow-through, or retractable assemblies based on serviceability and process conditions. Calibration solutions and automated cleaning or adjustment systems further improve long-term stability where fouling and drift would otherwise degrade control confidence.

Engineered Equipment Company, a leading supplier of specialized industrial equipment.