Patent ID: 9138669
Filing Date: 2015-09-22
Classification: B01D

Abstract:
1. A multilayer filter, comprising: (i) a composite filter medium; and (ii) a cover layer having a hydrophobic layer bonded to the cover layer and wherein the hydrophobic layer is gas permeable; wherein the composite filter medium comprises a layer of nanofibers coated on both sides of a substrate layer; wherein the composite filter medium is arranged into a plurality of sheets thereby forming the multilayer filter; wherein the thickness of all layers of nanofibers combined in the multilayer filter is at least 50% thicker than the thickness of nanofibers of a single-layer filter having all nanofibers deposited in a single layer; and wherein the total amount of nanofibers in the multilayer filter exceeds 0.2 gram per square meter of filter area.