Knowledge of the material moisture content is crucially important, for example, where drugs are processed in the form of pills and tablets. The powders used are mostly dried (e.g., in fluidized bed dryers), before being pressed into tablets. After drying the material moisture content must remain within a very narrow range as moisture can influence the characteristics of powders both during and after pressing (cohesion specific characteristics).
The material moisture content of products can be determined using different methods. The standard methods of thermos-gravimetric methods (weighing, drying) and Karl-Fischer-Titration are often used. Both are established methods which require trained personnel and clean application areas. For laboratory applications to determine the moisture content in plastics, we favor the Calcium hydride method. It is easy to apply and requires no calibration, because it is an absolute measurement.
In running drying processes we determine the equilibrium moisture close to the material. Relation to the moisture content is established with the creation of sorption isotherms, by simple comparative measurements or by using operator experience.
For determination of particle moisture in fluidized beds we have developed an innovative material collector.