Transmitted Light Refractometry Measurement Principle

Every substance is characterized by a specific relationship between its refractive index, the temperature and the concentration of its components. Once the refractive index and temperature of the medium are measured, the transmitter is capable of determining the concentration of the medium based on this relationship.

The PIOX® R Refractometer works with transmitted light. It determines the refractive index of a fluid on the basis of a measurement of the refraction angle of a light beam crossing a prism immersed in this fluid (Snellius' Law). The light emitted by the sensor's LED is parallelized and bundled before it crosses the fluid to be measured. At the surface of the measuring prism, the light beam is refracted and split in two.

On the CCD sensor behind the prism, two separate signals are detected. The distance between them is correlated with the refraction index through Snell's law. Together with the measured media temperature by the Pt1000 probe, the transmitter then calculates the temperature compensated refractive index nDT and other specific values such as m%, Brix or density.

By using materials selected for specific process needs, PIOX® refractometers offer the optimum solution to meet your analysis needs. The wetted probes comply with sanitary requirements for the food industry and are CIP-capable. Furthermore, models are available for especially corrosive chemicals.