The filter industry has useful rules of thumb for achieving the required emission level of a baghouse: typically, denser needle felts and finer fibers in the superficial layer tend to reduce emission levels and these levels also tend to be lower in case of more cohesive dusts. Unfortunately, these rules are far more approximate than those applied in other fields of air filtration, where one can rely on established metrics such as efficiency (measured, if needed, at various stages of filter loading) to obtain a quantitative relationship between the upstream and downstream dust concentrations (notably the concentration around the MPPS) for a certain class of filters. In case of periodically cleaned filter bags we do not have an established, straightforward relationship between the emission level and practical metrics for media construction or upstream dust properties; moreover the concept of efficiency is not considered useful, practically.
The paper reports experimental data for the emission levels (expressed as emitted mass per cleaning cycle and filter area) for a series of needle felt media with systematically varying properties...
Session: G9 - Surface Filtration
Day: 14 March 2018
Time: 13:00 - 14:15 h