Filter medium and breather filter structure
Thermoplastic bicomponent binder fiber can be combined with other media, fibers and other filtration components to form a thermally bonded filtration media. The filtration media can be used in filter units, such as breather caps. Such filter units can be placed in the stream of a mobile fluid and can remove a particulate and/or fluid mist load from the mobile stream. The unique combination of media fiber, bicomponent binder fiber and other filtration additives and components provide a filtration media having unique properties in filtration applications.
1. A thermally bonded nonwoven filter medium comprising about 10 to 90 wt % of a bicomponent fiber comprising a diameter of 5 to 50 microns, and about 10 to 90 wt % of a media fiber comprising a diameter of 0.1 to 5 microns, wherein the filter medium comprises a thickness of about 0.25 to 1.9 mm, a pore size of about 0.2 to 50 microns, a permeability of about 2 to 200 ft-min −1 , a solidity of about 2 to 25%, and a basis weight of about 2 to 200 g-m −2 .
2. A filter element comprising two or more layers of the filter medium of claim 1 .
3. The filter element of claim 2 further comprising a mechanical support.
4. The filter element of claim 3 wherein the mechanical support is a perforate support, wire support, or scrim.
5. The filter medium of claim 1 wherein the bicomponent fiber comprises a polyester.
6. The filter medium of claim 1 wherein the bicomponent fiber comprises a nylon.
7. The filter medium of claim 1 wherein the media fiber is a cellulosic media fiber or a synthetic media fiber.
8. The filter medium of claim 7 wherein the synthetic media fiber comprises polyester, nylon or polyolefin.
9. The filter medium of claim 1 wherein the media fiber comprises a combination of a cellulosic fiber and at least one of polyester, nylon or polyolefin.
10. A filter element comprising the filter medium of claim 1 and an additional filter medium, the additional filter medium different from the filter medium of claim 1 .
11. The filter element of claim 10 comprising two or more layers of the filter medium of claim 1 , the additional filter medium, or both.
12. The filter element of claim 11 further comprising a mechanical support.
13. The filter element of claim 12 wherein the mechanical support is a perforate support, wire support, or scrim.