Ultrasonic Powder Compacting
Hielscher Ultrasonics makes devices for the ultrasonic agitation of containers, vials, reactors or columns. The ultrasonic vibrations can shake powder particles after filling, in order to obtain a denser and or uniform powder packing.
Bulk density or packing density of powders and bulk materials has a significant influence on flowability, permeability and packing volume. After filling a dry or wet powder or powder slurry into a container, each powder particle is not in perfect position to the neighboring particles in the packing system.
Much like tapping a container for a specific number of times (e.g. 100 times), ultrasonic vibrations transmit mechanical shocks (taps) to the container up to 26,000 times per second. Using Hielscher ultrasonic devices with constant amplitude ensures that each tap is fully controllable and repeatable in magnitude and frequency. This leads to more consistent quality in analysis or manufacturing. A typical application is the compacting of HPLC columns during or after filling. In this case, the column itself is exposed to ultrasonic vibrations.
Generally, a low size ratio of coarse particles to fine particles results in a low packing density or low bulk density. Bulk density describes, how a material will settle or compact under pressure. It depends on both the powder particle density and the spatial arrangement of the particles in the powder bed.