Patent ID: 8038013
Filing Date: 2011-10-18
Classification: B01D

Abstract:
1. A filter cartridge comprising a composite liquid filtration medium comprising at least one nanoweb layer of polymeric nanofibers adjacent to and in a face to face relationship with a microfiltration membrane, wherein the nanoweb layer has a filtration efficiency rating of at least 95% for a particle size at which the membrane is rated with an LRV of 3.7 or greater, and the nanoweb layer has a thickness efficiency ratio of greater than about 0.01, and wherein the pressure drop across the nanoweb is less than or equal to 60% of that across the composite liquid filtration medium for a given fluid flow rate, and the nanoweb layer is positioned upstream of the microfiltration membrane and wherein the filter cartridge is in the form of a flat panel or a cylindrical unit.