Electrical Stimulation of Fabric Filtration

Abstract

The reductions in pressure drop that accompany the establishment of a strong electric field near a filter fabric appear to be due to three separate mechanisms. One is the formation of a more porous dust cake due to dust capture in the low packing density regions of the fabric. A second mechanism is attraction of particles to the bag wall which causes the bag to act like a precipitator. The thickness of the dust cake is then greater near the entrance than at the end of the bag, and this results in a lower pressure drop. The third mechanism involves the attraction of particles to the bag electrodes. The dust is then deposited in bands with relatively thin deposits in between. Measurements and visual inspections of the dust deposits indicate that the second and third effects are enhanced when the aerosol is precharged. A particle precharger of new design appears to be particularly suitable for this purpose and causes major changes in filtration performance.