SITA CleanoSpector - Measuring Principle
The SITA CleanoSpector is a handy device which can be easily used for the cleanliness inspection of contamination on parts' surfaces. The test result is measured in the degree of the cleanliness of parts made of metal or other materials in percent.The SITA CleanoSpector detects contamination due to their fluorescence which is excited by a light emitting diode (LED) with light in the ultraviolet range. A photodiode in the sensor head of the SITA CleanoSpector measures the intensity of the fluorescence. The higher the measured intensity of the fluorescence is, the more intense is the contamination and the lower is the displayed cleanliness.
oilfilm on stainless steel
The fluorescence which is excited by an ultraviolet radiation, is a special form of
the luminescence. Electrons of fluorescent molecules reach a higher energy level by
absorbing photons. Such an excited condition is energetically unstable. The electrons
return immediately into their initial state whereat the absorbed energy is released again.
At the same time, an emission of the fluorescence light takes place. Due to the fact that a
part of the energy is dissipated into heat,
the emitted radiation has less energy and for this reason a longer wavelength.
The parameters of the SITA CleanoSpector are optimally adapted to typical
contamination in cleaning processes. For special inspection tasks it is also
possible to adapt the wavelength of the light emitting diode. Due to the fact that
organic material has a strong self-fluorescence when it is exposed to ultra violet
light, it is possible to detect oil and grease contamination as well as surfactant residues.
Furthermore, it is possible to inspect corrosion preventive or wax layers with a defined thickness.
The following diagram shows the fluorescence spectrum of a cooling
lubricant while being excited at a wavelength of 365 nm. With an evaluation
wavelength of 460 nm, the contamination can be optimally detected with the
SITA CleanoSpector
because the intensity of the fluorescence is very high.
