The present invention is an air filter assembly which includes a frame having a filter mounted therein. The filter is constructed of woven microfilament strands having a cross-sectional height of at most 30 microns, the strands being spaced apart by at most 20 microns. The filter medium is single-ply...http://www.google.es/patents/US5492551?utm_source=gb-gplus-sharePatente US5492551 - Air filter assembly
