The PIOX® Refractometers

Refractometry in the Process

Refractometry is an ideal analytical procedure for an accurate and reliable measurement of a liquid's purity, concentration or density. A refractometer measures the refractive index of a fluid, a quantity which is characteristic for this specific substance and correlated to other properties such as concentration and density (more).

Refractometers are widely used for product detection, monitoring or regulating concentration as well as for quality control. They are a very common in laboratories where for example they are used for quality spot checks. With the growing importance of online process analysis, refractometers are now more and more used directly in the process.

FLEXIM's refractometers work with transmitted light. This method has the advantage of not being influenced by coating and deposits on the prism since the measurement does not take place at the ultra-thin boundary layer between the measurement prism and the medium, but directly in the volume flow (see measuring principle). The measurement is independent of viscosity and not sensitive to bubbles. No minimum flow is necessary.

Difference Measurement

The PIOX® refractometers also offer another special feature: a double prism difference measurement. The bundle of parallel light beams which has crossed the fluid is simultaneously refracted and divided in two by a double prism. The distance between those two light signals on the CCD sensor is used to determine the refractive index of the fluid. This patented method allows for a drift-free measurement, even when deposits are building at the surface of the prism.