How Transmitted Light Refractometers work?
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 (Snell’s Law). The light emitted by the sensor’s LED (590 nm, sodium D line) 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 intensity peaks are detected. The distance between them is correlated with the refraction index through Snell’s law. The refractive index can thus be calculated and sent to the electronic unit together with the temperature measured by the Pt1000 probe. The transmitter undertakes the calculation of the temperature compensated refractive index nDT. Further defined output quantities are calculated using the fluid’s characteristic curve.
