Process Photometers

Process Photometers

Process photometers measure optical absorbance at defined wavelengths to quantify dissolved substances or optical properties directly in the process. Depending on method and configuration, they may operate reagent-free (direct UV/Vis absorbance) or as part of a colorimetric approach where a reagent generates a measurable color proportional to concentration. The result is a continuous or frequently updated signal suitable for control, alarming, and documentation.

The core benefit is fast, selective measurement without manual sampling delays. Optical measurement enables immediate detection of changes in contaminant load, chemical dosing effectiveness, or treatment performance, supporting quicker corrective actions. When reagent-free methods are applicable, operating costs and maintenance complexity can be reduced compared with wet-chemistry analyzers.

Photometric systems are engineered around stable light sources, defined optical path lengths, and compensation for background effects such as turbidity or lamp aging. In reagent-based configurations, controlled dosing, mixing, and reaction timing are critical to accuracy and repeatability. Installation details - flow stability, avoidance of air bubbles, and optical window cleanliness - often dominate long-term performance.

Transmitters and analyzers typically provide multi-point calibration, diagnostics, and configurable outputs for integration into automation platforms. Automated cleaning (wipers, air purge, or chemical cleaning sequences) helps manage biofouling and scaling on optical surfaces. Trending and diagnostic flags are valuable for distinguishing true concentration changes from optical fouling or process interference effects.

Typical applications include monitoring disinfectant-related chemistries, nutrients, metals via colorimetric methods, and organic-related surrogates via UV absorbance where appropriate. Process photometry is widely used in drinking water, wastewater, and industrial water treatment, as well as in chemical and hygienic utilities where optical signals correlate strongly with quality. When matched to the right chemistry and installed with appropriate cleaning provisions, process photometers deliver rapid insight with strong operational value.

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