Quality sensor based on optical working principle exploiting the relantionship between the liquid concentration and the refractive index of the fluid. According the Snell’s law a variation on the refractive index of the fluid leads to have a change on the “critical angle” of total reflection. Using a light source (led) to produce an incident beam on the sensitive surface, the variation of the critical angle produces a different light intensity on the total reflected beams that can be evaluated through sensitive elements (photodiodes). Through dedicated sensor calibration, it is possible to correlate the fluid concentration with the optical measure.

Eltek optical technology doesn’t consider the optical ray refracted in fluid, only the reflected one, therefore it is not sentive to air bubbles or particles present into the fluid. ELTEK optical technology is used in application where it is necessary to have contactless solution for liquid concentration measure. Current optical geometry can be used to measure the concentration of Urea inside aqueous solution (AdBlue) or concentration of biodiesel in diesel. In general, the technology can be used to measure the concentration of any solutions, optimizing the optical sensitive area to the required concentration range.


Main benefits:

  • Not affected by particles or air bubbles.
  • Only a very thin layer of fluid is needed, concentration detection even at low fluid level – no part in motion, calibration in system non needed, easily adapted to any tank geometry.