Microwave moisture measurement on gypsum

On-line measurement for quality improvement

Microwave measurement is non-contacting; no sensor comes into contact with the product to be measured, which limits maintenance and avoids special cleaning. The measurement is not influenced by the colour or inhomogeneity of the measured product. Furthermore, the measurement is carried out on the entire product profile while traditional measurements only measure the surface of the material profile. In addition, the multi-frequency technique and the reference line enhance the stability and representativeness of the resulting measurement. Berthold’s Micro-Polar system is very easy to install. The transmitter has a large display and a user-friendly interface. Automatic calibration can also be performed on site.

Microwave moisture measuring principle

Microwaves pass through the product to be measured, causing rotation of the free water molecules, which have excellent dielectric properties. This rotation causes a deceleration (phase shift) and a drop in magnitude (attenuation) of the microwaves, resulting in a very accurate measurement of the water content. Thanks to the multi-frequency technique used by Berthold Technologies, the measurements are highly reliable and stable and are not affected by reflectance or resonance. The integrated reference line provides excellent compensation for potential environmental effects. As the instrument generates very low microwave power (around 0.1 mW), the measured product does not undergo any temperature rise or modification. The radio licenses of the system have been approved by the FCC, IC and ETSI.