MULTI-LAYERED COMPOSITE FILTER MEDIA AND PLEATED FILTER ELEMENT CONSTRUCTED THEREFROM
A multi-layered pleated filter element for filtering drinking water is disclosed which includes at least one upstream glass fiber layer for pre-filtration, a nanofiber membrane layer for bacteria retention, and at least one downstream positively charged microporous membrane layer for virus retention.
1 . A multi-layered composite filter media comprising:
a) at least one pre-filtration layer;
b) a bacteria retention layer; and
c) at least one virus retention layer.
2 . A multi-layered composite filter media as recited in claim 1 , wherein the at least one pre-filtration layer is a glass fiber pre-filtration layer.
3 . A multi-layered composite filter media as recited in claim 1 , wherein the bacteria retention layer is a nanofiber membrane layer.
4 . A multi-layered composite filter media as recited in claim 3 , wherein the nanofiber membrane layer is formed of an electrospun polymer resin.
5 . A multi-layered composite filter media as recited in claim 3 , wherein the electrospun polymer resin is Polyacrylonitrile (PAN).
6 . A multi-layered composite filter media as recited in claim 3 , wherein the nanofiber membrane layer includes a substrate made of polyethylene terephthalate (PET).
7 . A multi-layered composite filter media as recited in claim 6 , wherein the nanofiber membrane layer has an average thickness of about between 170 to 210 μm.
8 . A multi-layered composite filter media as recited in claim 7 , wherein the nanofiber membrane has a thickness of about between 30 and 60 μm and the substrate has an average thickness of about between 140 to 150 μm.
9 . A multi-layered composite filter media as recited in claim 1 , wherein the at least one virus retention layer is a positively charged microporous media layer.
10 . A multi-layered composite filter media as recited in claim 9 , wherein the positively charged microporous media layer includes a porous substrate with a cross-linked polymer coating.
11 . A multi-layered composite filter media as recited in claim 10 , wherein the porous substrate of the at least one virus retention layer is made of glass fiber.
12 . A multi-layered pleated filter element comprising:
a) at least one upstream glass fiber layer for pre-filtration;
b) an interior nanofiber membrane layer for bacteria retention; and
c) at least one downstream positively charged microporous media layer for virus retention.
13 . A multi-layered pleated filter element as recited in claim 12 , wherein the nanofiber membrane layer is formed of an electrospun polymer resin.
14 . A multi-layered pleated filter element as recited in claim 13 , wherein the electrospun polymer resin is Polyacrylonitrile (PAN).
15 . A multi-layered pleated filter element as recited in claim 13 , wherein the nanofiber membrane layer includes a substrate made of polyethylene terephthalate (PET).
16 . A multi-layered pleated filter element as recited in claim 13 , wherein the at least one positively charged microporous media layer includes a porous substrate with a cross-linked polymer coating.
17 . A multi-layered pleated filter element as recited in claim 16 , wherein the porous substrate of the at least one virus retention layer is made of glass fiber.
18 . A multi-layered pleated filter element as recited in claim 12 , including first and second glass fiber layers for pre-filtration.
19 . A multi-layered pleated filter element as recited in claim 12 , including first, second and third positively charged microporous media layers for virus retention.
20 . A filter cartridge comprising:
a) a housing having an inlet region for the ingress of an unfiltered fluid and an outlet region for the egress of filtered fluid; and
b) a multi-layered pleated filter element disposed within the housing and including:
i) at least one upstream layer for pre-filtration;
ii) an interior nanofiber membrane layer for bacteria retention; and
iii) at least one downstream positively charged microporous media layer for virus retention.
21 . A filter cartridge as recited in claim 20 , wherein the pleated filter element is a radially pleated filter element with an outer periphery and an inner periphery.
22 . A filter cartridge as recited in Clam 21 , wherein the upstream pre-filtration layer is positioned at the inner periphery of the pleated filter element.
23 . A filter cartridge as recited in Clam 21 , wherein the downstream virus retention layer is positioned at the outer periphery of the pleated filter element.
24 . A filter cartridge as recited in claim 20 , wherein the housing includes a cover portion having the inlet region, and wherein the inlet region is in fluid communication with the inner periphery of the filter element.
25 . A filter cartridge as recited in claim 20 , wherein the pleated filter element is potted on an interior surface of the cover portion.
26 . A filter cartridge as recited in claim 20 , including first and second glass fiber layers for pre-filtration.
27 . A filter cartridge as recited in claim 20 , including first, second and third positively charged microporous media layers for virus retention.
28 . A filter cartridge as recited in claim 20 , wherein the outlet region includes a plurality of circumferentially spaced apart outlet ports formed about an upper peripheral edge of the housing.