pH Sensors & Transmitters

pH Sensors & Transmitters

pH measurement systems provide continuous indication of acidity/alkalinity in liquids, using a pH sensor and transmitter to deliver a compensated, diagnostic-rich process signal. The measurement is fundamental to reaction control, corrosion management, biological treatment performance, and product quality across a wide range of industries. Because pH influences speciation, solubility, and reaction rates, it is often a primary control variable rather than a secondary indicator.

The benefit is direct control of critical chemistry with immediate feedback. Accurate pH monitoring supports optimized neutralization, improved precipitation and coagulation performance, reduced chemical overfeed, and protection of downstream assets. Continuous pH data also strengthens compliance assurance in discharge applications where permit limits require reliable documentation.

Sensor technology includes glass electrodes for general use, specialized glass formulations for high temperature or low conductivity, and alternative designs (such as ISFET-based sensors) for rapid response or difficult media. Reference junction design and electrolyte management strongly influence stability in dirty, sulfide-bearing, or high-solids services. Installation assemblies may include retractable housings, cleaning chambers, and automatic rinsing to maintain performance in fouling environments.

Transmitters add temperature compensation, filtering, alarm handling, and sensor diagnostics such as impedance monitoring and slope tracking. Diagnostics help detect glass aging, reference poisoning, and coating before measurement quality degrades to the point of control instability. Calibration strategy - buffer selection, frequency, and documentation - should be aligned to process criticality and exposure to fouling or chemical shock.

Typical applications include acid/caustic dosing, wastewater neutralization and compliance monitoring, chemical reaction control, cooling water and boiler utility conditioning, and hygienic processes such as CIP. pH is also central in biological treatment, where it affects nitrification, toxicity, and metal solubility. With correct sensor selection, installation, and maintenance planning, pH measurement remains one of the most powerful and cost-effective analytical tools in process control.

Instrumentation and Controls., an exclusive authorized representative of sales and service for Endress+Hauser.