A pleated filter is provided with electrically conductive fibrous material that releases ions to improve trapping efficiency. The edges of folded filter media are rendered emitting as by attaching conductive strings to the edges of the folds. The ends of the fibers in the strings are left exposed and,...http://www.google.es/patents/US6497754?utm_source=gb-gplus-sharePatente US6497754 - Self ionizing pleated air filter system
