Reflection Photometer
The reflection photometers of PIER-ELECTRONIC are used to analyse solid materials, such as wood, minerals, or grains. The product is illuminated with light of a suitable wavelength. The photometer spectrally analyses the light that is reflected by the target:
The measured raw data are transferred to an analyser which computes the required data, e.g., moisture, concentration, or thickness.
The photometers of PIER-ELECTRONIC are used in different industrial sectors for the quality control of various products. Typical applications include:
- Moisture measurements (water content) of sand, grains, wood, polymers, etc.
- Concentration measurements of certain minerals in raw salt
- Thickness measurements of coatings, foils, and films
- Whiteness control of sugar
The measurement principle
The illuminated sample reflects light in a typical pattern. The human eye detects this as the colour of the object. Our detectors are able to observe more wavelengths than the human eye, if required by the application. For example, moisture is detected using near-infrared light.The optics of the photometer focus the reflected light onto an adequate photodetector. The signal from that detector is then amplified and combined with the calibration parameters to display the required data.
If necessary, additional environmental parameters can be taken into account, as some measurements are sensitive to the temperature or to other components of the product.
A special method using modulated light ensures a high stability over time, and leads to a neglible influence of various interfering factors on the measured data.
The wavelengths for the measurement depend on the material and are selected from these sections of the electromagnetic spectrum:
| Ultraviolet (UV) | 190–400 nm |
| Visible light (VIS) | 400–700 nm |
| Near infrared (NIR) | 700–2500 nm |
| Infrared (IR) | 2500–4700 nm |