The sample material is fed through the height-adjustable funnel and stirrer onto the high-frequency feeder and continuously transported over the funnel-shaped opening of the dry measuring cell and then drops in the actual dispersion area. In a Venturi nozzle the powder is accelerated and passes with a high speed through the nozzle channel and the measurement of the particle size distribution in the laser beam takes place directly behind it. Then it passes a zone with aerodynamic wave generation at the nozzle outlet. The by the high turbulent current caused strong shearing forces, as well as blows between the particles lead to the breakdown of the agglomerates. No impact areas in the flight path of the particles exist in order to prevent soft sample materials from being ground during the dispersion process.
Compared with the wet dispersion is the dry dispersion not as efficient due to chemically-physical as well as rheological material properties of the sample material.
One of the main differences between dry and wet dispersion is based on the fact, that it is almost a solely mechanical dispersion in an air flow. Thereby, with a dry dispersion, a sensible measurable particle size and the associated complete primary particle dispersion is typically at approximately 1 - 10 µm. Depending on the material and its properties, below this range an incomplete dispersion can be expected. The utilization of the dry dispersion makes sense in areas where a wet dispersion in water or solvents has to be ruled out.