Cleaning of Fabric Filters

Abstract

The effectiveness of filter bag cleaning can become a critical factor during filtration at high velocities, since as velocity increases, dust removal becomes more difficult. Indeed, the efficiency of cleaning places practical limits on the gas flow rate. Mea surements of pressure drop and penetration for several filter bags at higher-than-normal face velocities indicate that with cleaning methods involving mechnical impact (e.g., pulse-jet or reverse air with shaking), there is a trade-off between excessive pressure drop at low impact energies and excessive penetration at high energies. It would seem, then, that improvements should come from better directed application of cleaning energy to stressing the bond between fabric and dust cake. Two novel substitutes for shaking during reverse air cleaning were tried: the application of an electric field to the filter, and shearing the bag fabric by twisting the bag support. The first was not effective, but even at a modest level of strain, bag shearing was equivalent to shaking.