ORP Sensors & Transmitters

ORP Sensors & Transmitters

ORP (oxidation-reduction potential) sensors and transmitters provide a real-time electrochemical indicator of the oxidizing or reducing character of an aqueous process. ORP is often used as a trend signal for disinfection capability, aeration control in wastewater, detoxification steps in electroplating, and redox-driven treatment processes such as flue gas scrubbing. The measurement is especially valuable where a stable redox environment is required for consistent reaction outcomes.

ORP measurement is performed using a precious metal measuring electrode (commonly silver, gold, or platinum) paired with a stable reference system such as Ag/AgCl. The measured potential reflects electron activity in the medium, and the ORP value is calculated from the potential difference between the measuring and reference systems using the Nernst equation, typically expressed in mV. Because ORP represents the combined effect of multiple redox pairs, it is a sum parameter and does not identify individual substances or concentrations.

Selection is application-driven. Gold electrodes are positioned for oxidation processes (for example cyanide oxidation or ozone measurement), while platinum electrodes are positioned for reducing processes (such as chromate reduction or chlorine dosing). Matching diaphragm and reference design to fouling risk, chemical compatibility, and stability requirements is central to achieving durable, low-drift operation. Temperature reporting is also important because redox potential is temperature dependent and must be stated to compare measurements.

Benefits include actionable trend information for control decisions and a portfolio that scales from basic measurement to broader multiparameter strategies. The offering includes pH/ORP combination sensors that provide both pH and ORP values for a more detailed picture and can support rH determination. Calibration and adjustment are supported through ORP buffers, solutions, and standards designed to maintain confidence in the electrochemical loop over time.

Typical applications span drinking water and pool disinfection monitoring, wastewater treatment control, and industrial oxidation/reduction processes where redox balance is tied to product quality or environmental performance. Integration with suitable transmitters and assemblies enables stable installation in open basins, pipelines, or sampling loops, and supports consistent measurement in hygienic or hazardous-area conditions where required.

At Eastern Controls, We are proud to be the exclusive authorized sales and service representative for Endress+Hauser.