Process and materials for coiling z-filter media, and/or closing flutes of filter media; and, products
Approaches to providing z-filter media constructions are provided. Preferred corrugated media, filter constructions having such corrugated media, and filter systems using such filter constructions are provided. Also, preferred methods of forming filter constructions are provided.
1. A method of preparing a filter construction for use in an air cleaner; the method comprising steps of:
(a) providing a filter media construction comprising a fluted filter media sheet secured to a facing sheet of filter media with a first seal therebetween against a first side of the facing sheet;
(b) forming a generally circular coiled configuration by coiling the filter media combination at least 10 times around with the facing sheet directed to the outside of the coiled configuration and with a sealant strip, during the coiling, positioned between the fluted filter media sheet and a second side of the facing sheet;
(i) the step of forming a coiled configuration comprising providing a resulting generally circular coiled configuration in the form a coreless coil having: a central open space; and, an outside perimeter of at least 60 cm;
(c) distorting the generally circular coiled configuration having a central aperture to a media construction having a shape with two generally parallel sides joined at their ends by curved portions;
(i) the step of distorting including closing the central open space with sealing of the fluted filter media to itself, by a sealant, to provide a media construction having a shape with no center core; and,
(ii) the step of distorting comprising forming an inner sealant strip in a center of the resulting media construction that is at least 12 cm long; and,
(d) positioning a housing seal on the media construction.
2. A method according to claim 1 wherein:
(a) the step of forming a generally circular coiled configuration comprises coiling the filter media on a hub and then removing a resulting generally circular coiled configuration from the hub to provide the coreless coil having a central open space.
3. A method according to claim 2 wherein:
(a) the first seal between the fluted media sheet and the facing sheet comprises a sealant strip.
4. A method according to claim 1 wherein:
(a) the sealant strip positioned between the fluted filter media and the second side of the facing sheet is a polyurethane composition that increases in volume during cure.
5. A method according to claim 4 wherein:
(a) the sealant strip positioned between the fluted filter media and the second side of the facing sheet is a polyurethane composition that increases in volume by at least 40% during cure.
6. A method according to claim 1 wherein:
(a) the step of positioning a housing seal comprises positioning a framework on the filter media construction and providing a housing seal on the framework.
7. A method according to claim 1 wherein:
(a) said step of distorting comprises forming at least six interdigitized flutes along a center strip of the z-filter media construction, in the region of the second sealant strip.
8. A method according to claim 1 wherein:
(a) the step of distorting comprising distorting such that the second sealant strip forms the central seal in the resulting construction with no center core.
9. A method according to claim 1 including:
(a) adding polyurethane to a space inside of the coreless coil to form the media construction.
10. A method according to claim 1 wherein:
(a) providing a foamed polyurethane housing seal gasket secured to the outer surface of the media construction.
11. A method according to claim 1 wherein:
(a) the facing sheet is a non-corrugated sheet.
12. A method according to claim 1 including a step of:
(a) applying the second sealant strip to the fluted sheet before coiling with:
(i) a selected amount of sealant applied a first distance from a nearest edge of the filter media construction at a first location of the filter media construction adjacent a lead edge of the strip;
(ii) a selected amount of sealant applied to a second distance from the nearest edge of the filter media construction in a second location of the filter media construction following the first portion, the first distance being further than the second distance; and,
(iii) a selected amount of sealant applied a location of the filter media construction near a tail end and at a location further from a closest edge than the sealant on the second portion of the filter media construction.
13. A method according to claim 1 wherein:
(a) said step of coiling includes guiding an extension of the filter media construction into a media catch slot of a winding hub and winding the hub to coil the filter media construction.
14. A method according to claim 1 including a step of:
(a) sealing a tail end of the media along its length by a sealant.
15. A method according to claim 14 including a step of:
(a) sealing a tail end of the media along its length by a hot melt sealant.
16. A method according to claim 14 wherein:
(a) the tail end of the media is positioned along a straight side of the media construction.
17. A method according to claim 1 including a step of:
(a) mounting a framework on the obround shape coil resulting from the step of distorting.
18. A method according to claim 17 including a step of:
(a) providing a housing seal ring on the framework.
19. A method according to claim 17 wherein:
(a) the step of mounting a framework includes mounting a framework having a plastic cross piece positioned as a face lattice.