Flow of Coating Colors Through Filters, 2003 Spring Technical Conference Proceedings

This paper concerns the study of the flow of viscous Newtonian and non-Newtonian fluids through filters and provides an explanation of clogging phenomena.

In the first part, a general expression leading to the pressure drop through filters as a function of flow rate, rheological properties of fluids and the characteristics of filters (wire gauzes and slotted filters) is established using model fluids (Newtonian and non-Newtonian). In the case of pre-filtered coating colors, exhibiting a non-Newtonian behavior, the predicted and experimental pressure drop values (measured with pilot and industrial filters) are in good agreement.

In the second part, the clogging of the filter is studied. In the case of fluids polluted by non fragmentary particles, we find that the clogging phenomena could be modeled by the formation of a mono-layer of particles on the filters. A clogging model, based on the blockage of the slots by the retained particles gives suitable results. In the case of fluids polluted by fragmentary particles or fibers, the calculation is more difficult because the probability of the particles or fibers being stopped by the filter is a function of time.