Initial Collection Efficiency of Electret Filter and Its Durability for Solid and Liquid Particles [Translated]†

Abstract

Expressions to describe the initial collection efficiency of electret filters for both charged and neutral particles were derived covering a wide range of Coulombic force and induced force parameters including the interceptional effect. The prediction equations were in good agreement with the experimental data. Further, the electret charge stability in humid air and in exposure to liquid and solid particles was studied by measuring the time dependency of the particle penetration. It was found that the electret charge is quite stable in humid air but that it is gradually attenuated when exposed to organic droplets because the collected organic droplets spread over the fibers and weaken the electric field around them.† This report was originally printed in KAGAKU KOGAKU RONBUNSHU 18(2), 240-247 (1992) in Japanese, before being translated into English by KONA Editorial Committee with the permission of the editorial committee of the Soc. Chemical Engineers, Japan.