by Paul Dunst, Peter Bornmann, Tobias Hemsel, Walter Littmann, Walter Sextro
Abstract:
The transportation of dry fine powders is an emerging technologic task, as in biotechnology, pharmaceutical or coatings industry particle sizes of processed powders are getting smaller and smaller. Fine powders are primarily defined by the fact that adhesive and cohesive forces outweigh the weight forces. This leads to mostly unwanted agglomeration (clumping) and adhesion to surfaces, what makes it more difficult to use conventional conveyor systems (e. g. pneumatic or vibratory conveyors) for transport. A rather new method for transporting these fine powders is based on ultrasonic vibrations, which are used to reduce friction and adhesion between powder and the substrate. One very effective set-up consists of a pipe, which vibrates harmoniously in axial direction at low frequency combined with a pulsed radial high frequency vibration. The high frequency vibration accelerates the particles perpendicular to the surface of the pipe, which in average leads to lower normal and thereby smaller friction force. With coordinated friction manipulation the powder acceleration can be varied so that the powder may be greatly accelerated and only slightly decelerated in each excitation period of the low frequency axial vibration of the pipe. The amount of powder flow is adjustable by vibration amplitudes, frequencies, and pulse rate, which makes the device versatile for comparable high volume and fine dosing using one setup. Within this contribution an experimental set-up consisting of a pipe, a solenoid actuator for axial vibration and a piezoelectric actuator for the radial high frequency vibration is described. An analytical model is shown, that simulates the powder velocity. Finally, simulation results are validated by experimental data for different driving parameters such as amplitude of low frequency vibration, pipe material and inclination angle.
Reference:
Dunst, P.; Bornmann, P.; Hemsel, T.; Littmann, W.; Sextro, W.: Transportation of dry fine powders by coordinated friction manipulation. PAMM Proc. Appl. Math. Mech. 16, 2016.
Bibtex Entry:
@INPROCEEDINGS{Dunst2016-PAMM,
author = {Dunst, Paul AND Bornmann, Peter AND Hemsel, Tobias AND Littmann,
Walter AND Sextro, Walter},
title = {Transportation of dry fine powders by coordinated friction manipulation},
booktitle = {PAMM Proc. Appl. Math. Mech. 16},
year = {2016},
pages = {635-636},
address = {Braunschweig},
abstract = {The transportation of dry fine powders is an emerging technologic
task, as in biotechnology, pharmaceutical or coatings industry particle
sizes of processed powders are getting smaller and smaller. Fine
powders are primarily defined by the fact that adhesive and cohesive
forces outweigh the weight forces. This leads to mostly unwanted
agglomeration (clumping) and adhesion to surfaces, what makes it
more difficult to use conventional conveyor systems (e. g. pneumatic
or vibratory conveyors) for transport. A rather new method for transporting
these fine powders is based on ultrasonic vibrations, which are used
to reduce friction and adhesion between powder and the substrate.
One very effective set-up consists of a pipe, which vibrates harmoniously
in axial direction at low frequency combined with a pulsed radial
high frequency vibration. The high frequency vibration accelerates
the particles perpendicular to the surface of the pipe, which in
average leads to lower normal and thereby smaller friction force.
With coordinated friction manipulation the powder acceleration can
be varied so that the powder may be greatly accelerated and only
slightly decelerated in each excitation period of the low frequency
axial vibration of the pipe. The amount of powder flow is adjustable
by vibration amplitudes, frequencies, and pulse rate, which makes
the device versatile for comparable high volume and fine dosing using
one setup. Within this contribution an experimental set-up consisting
of a pipe, a solenoid actuator for axial vibration and a piezoelectric
actuator for the radial high frequency vibration is described. An
analytical model is shown, that simulates the powder velocity. Finally,
simulation results are validated by experimental data for different
driving parameters such as amplitude of low frequency vibration,
pipe material and inclination angle.},
doi = {10.1002/pamm.201610306},
file = {Dunst2016-PAMM.pdf:Dunst2016-PAMM.pdf:PDF},
owner = {ekubi},
timestamp = {2017.01.13},
url = {http://onlinelibrary.wiley.com/doi/10.1002/pamm.201610306/full}
}