Document 7R6yX81DyZ7nyDe6KkmG77qK8

256 W. N. WITHEMDGE II Figure 12A. Cloth-covered-screen filter assembly arranged for automatic reverse-air filter fabric. (Courtesy Pangbom Corp., Hagerstown, Md.) . cause of. the excessive space requirement, which increases' approxp portion to the increase in effectiveness desired, specified on the degree or 238). a -Air velocities through electric precipitators.are moder,ate.;...theyas! those used for filtration with fabrics and those required for inertiaf|sepa Accordingly, pressure drop is low, and wear due to abrasion is jBIuiM; same time, air distribution can be a problem with low velocities. anqlSSt, necessary to provide distributing plates, dividers, or filters at the inlet uniform approach to the charging and precipitating zones. fr- AIR CLEANING th ( frlAVil S8H u CENTER ROW CLEANED Or RIVKRfE AIR FLOW " THROOOH OPENINGS IN MANIFQLO DIAPHRAGM NORMAL PLOW SLOCKED_____ BY MANIFOLD DIAPHRAGM -CLEANED BAOS dk 257 pi ^MANIFOLD ZD/ z SCREEN FRAMES DUST DtpOSIT ON BAOS -MANIFOLD DIAPHRAGM J^P^viqw'"of re,verse-air-flow mechanism for cleaning filter bags. (Courtesy Pang- * ' J ^.. born Corp., Hagerstown, Md.) Wk ^Rf&tivity oj Dust Deposits. Two electric properties of the deposit ;;w |trodes have an important effect on the performance of electric l$eWe (1) the conductivity or resistivity and (8) the breakdown i ^hr-The-h'igher-the-dieleoir-io-strengbhrpf-the-dust-layer, the ^||fhpreeipitation process to the effects,;pf|high resistivity.9 ^gjphon, using water vapor, is an effective-fmethod of reducing the -""-^articles. Other vapors or gases, which in small concentrations f,to reduce resistivity of specific dusts, may be present in the jgjSngffi fee added as "conditioning agents." By experience and research, Ey*^||l|r|cipitators have'Tearned .about a nbmber of such favorable ||q. m precipitators applied to air-conditioning systems not only ^-dust-h-ol-d-ing ability of;.electrodes, but,' also may contribute to qc^y'rbducih'g the resistivity of the dust.10 'f'v ^iMlE-STAGE HIGH-VOLTAGE PRECIPITATORS l^pinitators for removing solids or liquids from industrial process \npej%atei.at. voltages from 25,000 to 100,000, direct current. The jrojllewystem of rods oFwres^is ma'intaineH at a-negative potential, y^irnparts a negative charge to particles suspended in the gas. The gWcjcie'jfirrangement leads to the description of single-stage precipi- ' /'*' / g^Mech. Eng., 77, 254 (abstract) (March, 1955). eflffiraM. Am. Inst. Elec. Engrs., 70, 1009-1013 (1951). 1