DWF-AWB-35

ONLINE MOISTURE MEASUREMENT

All measuring methods for online moisture measurement must be adjusted to the material to be determined. The measurement results therefore require a conversion to the product moisture, a direct measurement of the material moisture is only possible in the laboratory (Karl Fischer titration, weighing drying). In practice, therefore, material samples are often taken from the ongoing production at defined intervals, the water content of which is then determined in the laboratory. This method records the material moisture with a considerable time delay, and it must also be ensured that the material sample does not change during transport from production to the laboratory.

Various measuring methods are available for on-line moisture measurement, which are suitable for the determination of the material moisture content, depending on the application. Frequently used methods are infrared, microwave, conductivity or capacitive measurements. For example, quite complex infrared systems are used for moisture measurement in paper machines.

One of the most frequently underestimated possibilities for on-line moisture measurement is the determination of the compensating humidity. The chemically or physically unbound water content of a material wants to compensate itself by its water vapor partial pressure with its environment. Thus, e.g. With a cost-effective capacitive sensor for determining the humidity in the immediate vicinity of the material, the moisture can be determined in relation to the material moisture. This can be done either by the creation of sorption isotherms or by the use of corresponding experience values. In closed systems, for example dryers, the water discharge can be determined by determining the water content of the air (absolute humidity g / m³) in the supply and exhaust air.

The dr.wernecke Feuchtemesstechnik GmbH has a wealth of experience for various applications for the determination of the compensating humidity. Thus, e.g. The water content of coffee can be determined with this method during production, transport and storage in silos using the same measuring method (capacitive moisture sensors).

The dr.wernecke Feuchtemesstechnik GmbH has a wealth of experience for various applications for the determination of the compensating humidity. Thus, e.g. The water content of coffee can be determined with this method during production, transport and storage in silos using the same measuring method (capacitive moisture sensors).