Figures & data
TABLE 1 Tested full-scale bag filters and their properties. Pressure drops were measured at 0.944 m3/s
TABLE 2 Tested filter samples and their properties. Pressure drops were calculated for an air velocity of 12.3 cm/s through the filter medium
FIG. 1 SEM images of the simulated filter media: #9 glass fiber; #10 uncharged synthetic fiber; #14 charged synthetic fiber.
![FIG. 1 SEM images of the simulated filter media: #9 glass fiber; #10 uncharged synthetic fiber; #14 charged synthetic fiber.](/cms/asset/d99a0b30-7ae4-4b66-ab65-0ef7052b4af9/uast_a_766667_o_f0001g.gif)
FIG. 2 Sketches of the full-scale (a) and small-scale (b) filter test rigs. (Color figure available online.)
![FIG. 2 Sketches of the full-scale (a) and small-scale (b) filter test rigs. (Color figure available online.)](/cms/asset/063c7bf4-3f97-42f0-b3a9-cb55d5ea9837/uast_a_766667_o_f0002g.jpg)
TABLE 3 Summary of filter efficiencies obtained using the neutralized DEHS aerosol in the full-scale test rig at an air velocity of 0.16 m/s through the filter medium; the uncertainties are expressed as the standard deviation (efficiency percentage units)
FIG. 3 MPPS observed at three different air velocities through the filter medium. The data were obtained for both glass fiber filters and charged synthetic filters of various classes. The measurements were made using the neutralized DEHS aerosol in the full-scale test rig.
![FIG. 3 MPPS observed at three different air velocities through the filter medium. The data were obtained for both glass fiber filters and charged synthetic filters of various classes. The measurements were made using the neutralized DEHS aerosol in the full-scale test rig.](/cms/asset/2d7e9726-0d3a-4de7-b05c-28557bcd5470/uast_a_766667_o_f0003g.gif)
FIG. 4 Reduction of filtration efficiency at 0.22 m/s compared to that observed at 0.08 m/s. The data comprise M6-F8 glass fiber filters and charged synthetic filters tested with the neutralized DEHS aerosol in the full-scale test rig. GF: glass fiber filters; CS: charged synthetic filters.
![FIG. 4 Reduction of filtration efficiency at 0.22 m/s compared to that observed at 0.08 m/s. The data comprise M6-F8 glass fiber filters and charged synthetic filters tested with the neutralized DEHS aerosol in the full-scale test rig. GF: glass fiber filters; CS: charged synthetic filters.](/cms/asset/732bb336-30a3-445d-97b9-33a981ea2f35/uast_a_766667_o_f0004g.gif)
FIG. 5 Results from the full-scale filter tests using the neutralized DEHS aerosol. Filtration efficiency values based on MPPS plotted against values based on 0.4 μm particles, for glass fiber filters (a) and charged synthetic filters (b). The average efficiency and the standard deviation are taken from repeated measurements in a full-scale filter test.
![FIG. 5 Results from the full-scale filter tests using the neutralized DEHS aerosol. Filtration efficiency values based on MPPS plotted against values based on 0.4 μm particles, for glass fiber filters (a) and charged synthetic filters (b). The average efficiency and the standard deviation are taken from repeated measurements in a full-scale filter test.](/cms/asset/703aedbd-6884-4780-bc3d-134659e8a2dd/uast_a_766667_o_f0005g.gif)
FIG. 6 Fractional filtration efficiency observed for one glass fiber filter (GF) and one charged synthetic filter (CS), both of class F7. The measurements were made in the full-scale test rig at 0.22 m/s using the DEHS test aerosol. For each filter, one measurement was made with, and one without neutralization of the aerosol.
![FIG. 6 Fractional filtration efficiency observed for one glass fiber filter (GF) and one charged synthetic filter (CS), both of class F7. The measurements were made in the full-scale test rig at 0.22 m/s using the DEHS test aerosol. For each filter, one measurement was made with, and one without neutralization of the aerosol.](/cms/asset/baa95468-c36d-4b3b-b9ca-6ff45c02b651/uast_a_766667_o_f0006g.gif)