Composite filter media
View Patent ↗A composite filter media structure includes, in an exemplary embodiment, a base substrate that includes a nonwoven synthetic fabric formed from a plurality of fibers with a spunbond process. The base substrate has a minimum filtration efficiency of about 50%, measured in accordance with ASHRAE 52.2-1999 test procedure A nanofiber layer is deposited on one side of the base substrate. The composite filter media structure has a minimum filtration efficiency of about 75%, measured in accordance with ASHRAE 52.2-1999 test procedure.
1. A composite filter media structure comprising:
a base substrate comprising a nonwoven synthetic fabric formed from a plurality of fibers with a spunbond process, said base substrate having a minimum filtration efficiency of about 50% capture of particles having a size of about 0.3 μm to about 0.4 μm, measured in accordance with ASHRAE 52.2-1999 test procedure, said base substrate having a resistance less than about 2.5 mm of water, measured in accordance with EN-1822 (1998), said nonwoven synthetic fabric comprises a bond area pattern comprising a plurality of substantially parallel discontinuous lines of bond area, each discontinuous line of bond area comprising a plurality of linear lines of bond area arranged end to end with a non bond area between each linear line of bond area; and
a nanofiber layer deposited on one side of said base substrate, said composite filter media structure having a minimum filtration efficiency of about 75% capture of particles having a size of about 0.3 μm to about 0.4 μm, measured in accordance with ASHRAE 52.2-1999 test procedure.
2. A composite filter media structure in accordance with claim 1 , wherein said base substrate and said nanofiber layer in combination are substantially electrically neutral.
3. A composite filter media structure in accordance with claim 1 , wherein said plurality of fibers comprise a plurality of bicomponent fibers comprising a core material and a sheath material, said sheath material having a lower melting point than the core material.
4. A composite filter media structure in accordance with claim 1 , wherein said nanofiber layer is formed by electro-blown spinning, electrospinning, centrifugal spinning, or melt blowing.
5. A composite filter media structure in accordance with claim 3 , wherein said core material comprises at least one of polyester, polyamide, polyolefin, thermoplastic polyurethane, polyetherimide, polyphenyl ether, polyphenylene sulfide, polysulfone, and aramid.
6. A composite filter media structure in accordance with claim 1 , wherein said base substrate has a basis weight of about 100 g/m 2 to about 300 g/m 2 .
7. A composite filter media structure in accordance with claim 1 , wherein said nanofiber layer comprises a plurality of nanofibers having an average diameter of about 500 nm or less, said nanofiber layer having a basis weight of about 0.6 g/m 2 to about 20 g/m 2 .
8. A composite filter media structure in accordance with claim 1 , wherein said nanofiber layer comprises a plurality of nanofibers having an average diameter of about 500 nm or less, said nanofiber layer having a basis weight of about 1.5 g/m 2 to about 2.5 g/m 2 .
9. A composite filter media structure in accordance with claim 1 , wherein said nonwoven synthetic fabric comprises a bond area of said spunbond fibers of about 10% to about 16% of an area of said fabric.
10. A composite filter media structure in accordance with claim 1 , wherein said plurality of fibers comprise an average diameter of about 12 to about 25 microns.
11. A composite filter media structure in accordance with claim 1 , wherein said composite filter media structure has a resistance less than about 4.0 mm of water, measured in accordance with EN-1822 (1998).
12. A composite filter media structure in accordance with claim 11 , wherein a quality factor Q f of said composite filter media structure is greater than about 450.
13. A composite filter media structure in accordance with claim 11 , wherein a quality factor Q f of said composite filter media structure is greater than about 500.
14. A filter element comprising a first end cap, a second end cap, and a composite filter media structure, the composite filter media structure comprising:
a base substrate comprising a nonwoven synthetic fabric formed from a plurality of fibers with a spunbond process, said base substrate having a minimum filtration efficiency of about 50% capture of particles having a size of about 0.3 μm to about 0.4 μm, measured in accordance with ASHRAE 52.2-1999 test procedure, said base substrate having a resistance less than about 2.5 mm of water, measured in accordance with EN-1822 (1998), said nonwoven synthetic fabric comprises a bond area pattern comprising a plurality of substantially parallel discontinuous lines of bond area, each discontinuous line of bond area comprising a plurality of linear lines of bond area arranged end to end with a non bond area between each linear line of bond area; and
a nanofiber layer deposited on one side of said base substrate, said composite filter media structure having a minimum filtration efficiency of about 75% capture of particles having a size of about 0.3 μm to about 0.4 μm, measured in accordance with ASHRAE 52.2-1999 test procedure.
15. A filter element in accordance with claim 14 , wherein said base substrate and said nanofiber layer in combination are substantially electrically neutral.
16. A filter element in accordance with claim 14 , wherein said plurality of fibers comprise a plurality of bicomponent fibers comprising a core material and a sheath material, said sheath material having a lower melting point than the core material.
17. A filter element in accordance with claim 14 , wherein said nanofiber layer is formed by electro-blown spinning, electrospinning, centrifugal spinning, or melt blowing.
18. A filter element in accordance with claim 16 , wherein said core material comprises at least one of polyester, polyamide, polyolefin, thermoplastic polyurethane, polyetherimide, polyphenyl ether, polyphenylene sulfide, polysulfone, and aramid.
19. A filter element in accordance with claim 14 , wherein said base substrate has a basis weight of about 100 g/m 2 to about 300 g/m 2 .
20. A filter element in accordance with claim 14 , wherein said nanofiber layer comprises a plurality of nanofibers having an average diameter of about 500 nm or less, said nanofiber layer having a basis weight of about 0.6 g/m 2 to about 20 g/m 2 .
21. A filter element in accordance with claim 14 , wherein said nanofiber layer comprises a plurality of nanofibers having an average diameter of about 500 nm or less, said nanofiber layer having a basis weight of about 1.5 g/m 2 to about 2.5 g/m 2 .
22. A filter element in accordance with claim 14 , wherein said nonwoven synthetic fabric comprises a bond area of said spunbond fibers of about 10% to about 16% of an area of said fabric.
23. A filter element in accordance with claim 14 , wherein said plurality of fibers comprise an average diameter of about 12 to about 25 microns.
24. A filter element in accordance with claim 14 , wherein said composite filter media structure has a resistance less than about 4.0 mm of water, measured in accordance with EN-1822 (1998).
25. A filter element in accordance with claim 24 , wherein a quality factor Q f of said composite filter media structure is greater than about 450.
26. A filter element in accordance with claim 14 , wherein said composite filter media structure further comprises a plurality of pleats.