Pressure Drop. Figure 2 shows the comparison of the
pressure drop of irrigated bag filters and that of dry ones
when they are clean. As is shown in Figure 2 the characteristics of pressure drop considerably differ from each
other. Figure 3 indicates the same comparison but with
dust loads. Because of washing action against deposited
dusts by the down stream of water, almost 'no pressure
rise occurred in irrigated bag filters. For certain dusts,
however, which contain some tar substances, the pressure
drop increased with operation period.