Patent ID: 7938276
Filing Date: 2011-05-10
Classification: B01D

Abstract:
1. A filter bag for use in a pressurized liquid filtering system for filtering a fluid containing contaminants having a predetermined size, comprising: a ring member; and a filter bag configured to withstand high pressures, said filter bag formed from a plurality of layers that are coextensive with a surface of said filter bag, said filter bag having a tubular form that is closed at one end and affixed at a periphery of said tubular form to said ring member at an opposing end to define an input orifice of said filter bag, said plurality of layers including at least one pre-filtration layer, at least one filtration layer, and at least one post-filtration support layer, said plurality of layers collectively secured together with at least one weld to form said filter bag and specifically configured for filtration of particle contaminants of said predetermined size; wherein said pre-filtration layer defines an innermost layer of said filter bag and is comprised of at least one of a monofilament material and a micro-fiber material for collecting particles from a fluid being pumped through the filter bag, said at least one filtration layer is comprised of alternating layers of an adsorbent medium, an absolute-rated micro-fiber medium and a diffusion medium, said adsorbent medium formed of at least one layer of a thin wall substrate, and a granular material distributed on a surface of said at least one thin wall substrate and formed of a material for removing organic contaminants from the fluid, said granular material fixed to said at least one layer of said thin wall substrate; wherein a first layer of said diffusion medium is disposed between two layers of adsorbent medium and a second layer of said diffusion medium is disposed between one of said two layers of adsorbent medium and one layer of absolute-rated micro-fiber medium; wherein said first layer of diffusion medium comprises a non-adsorbent mesh material formed of a plurality of spaced apart parallel strands in a first plane and a plurality of spaced apart parallel strands in a second plane which are not parallel to the strands in the first plane, said parallel strands defining passages configured for permitting fluid flow from one side of said diffusion medium to an opposing side, in a direction transverse to said first and second planes, said passages coextensive with and adjacent to a surface of said two layers of adsorbent medium, said passages forming openings in said diffusion medium which are substantially larger than said contaminant of predetermined size to be filtered and configured for diffusing a fluid over a surface area of a second one of said two layers of adsorbent medium downstream from a first one of said two layers of adsorbent medium thereby enhancing an adsorption of organic contaminants by said two layers of adsorbent medium; wherein said diffusion medium further comprises first lateral openings defined by adjacent pairs of strands in said first plane and configured to accommodate fluid flow in a first direction aligned with said parallel strands in said first plane, and second lateral openings defined by adjacent pairs of strands in said second plane and configured to accommodate fluid flow in a second direction aligned with said parallel strands in said second plane, a size of said first and second lateral openings limited by a thickness or diameter of said parallel strands in those areas where said lateral openings traverse strands in an adjacent one of said first or second planes so that said lateral openings are substantially smaller in at least one dimension as compared to said passages, wherein said first diffusion medium is configured to provide an increased surface area for collection of said contaminant between layers of adsorbent medium but includes passages that are substantially larger than said contaminant to be filtered from said fluid; and said post filtration support layer is placed downstream from said filtration layer so that said post filtration support layer defines an outermost layer of said filter bag, said post filtration support layer being comprised of a fibrous fabric for preventing fiber migration downstream.