| 摘要 |
There is provided a nonwoven electret fiber filter formed with a nonwoven web of electret fibers needle-punched to an open scrim support. The scrim support material has individual discrete open areas with an average cross-sectional area as viewed from the plane of the filter media of at least 0.25 mm2, preferably 1.0 mm2, and a pressure drop across the scrim support, without the filter web, of less than 1.5 mm H2O measured at 98.4 meters/min gaseous face velocity. The resulting filter has enhanced lifetimes, a low pressure drop and high filtration efficiencies.
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