Possibilities to improve the short-term dosing constancy of volumetric feeders

For some applications, e.g. processes with stoichiometric reactions or the mixing of powders in a static mixer, a high short-term dosing constancy is necessary. For the dosing of calcium carbonate with a median diameter of 2 mum, it is shown that the pulsation of a volumetric feeder can be reduced tremendously by the use of different attachments for the dosing tube. The best results were obtained with a self-developed rotating star attachment. The quantitative assessment of the efficiency was performed both in the time domain with the standard deviation and in the frequency domain with the fast Fourier transformation. (C) 2003 Elsevier B.V. All rights reserved.