Enhanced performance fibrous filter media and extended life fluid filter assembly

摘要

Enhanced performance fibrous media (60) is provided by orienting filter media fibers (62) dominantly parallel to the fluid flow direction (46). Filter media construction is provided by a sheet (80) having an internal pleated subsheet (88) with pleats (92, 94) engaging and packed against each other sufficiently tightly and bonded (104) such that fluid flows along the flow direction through the pleats in parallel therewith, rather than between the pleats and then transversely therethrough. An extended life two-stage fluid filter assembly includes first and second filter elements (80 and 112), wherein the pleats (114, 116) of a main downstream filter element (112) are spaced from each other along a spacing direction (122) transverse to the flow direction (46) and defining a transverse gap (124) therebetween through which fluid flows, and wherein the pleats (92, 94) of an upstream prefilter element (80) are packed against each other without such transverse gap and blocking fluid flow therebetween.