High efficiency filter media
Filtration media packs, filter elements, and media are disclosed, including media packs having a plurality of layers of single facer media wherein the layers of single facer media include a fluted sheet, a facing sheet, and a plurality of flutes extending between the fluted sheet and the facing sheet, with the fluted sheet and facing sheet formed of multi-layer media can include a polytetrafluoroethylene (PTFE) layer supported by a polymeric scrim layer.
1. A filtration media pack comprising:
(a) a plurality of layers of single facer media wherein the layers of single facer media comprise a fluted sheet, a facing sheet, and a plurality of flutes extending between the fluted sheet and the facing sheet and having a flute length extending from a first face of the filtration media pack to a second face of the filtration media pack;
(b) a first portion of the plurality of flutes being closed to unfiltered fluid flowing into the first portion of the plurality of flutes, and a second portion of the plurality of flutes being closed to unfiltered fluid flowing out of the second portion of the plurality of flutes so that fluid passing into one of the first face or the second face of the media pack and out the other of the first face or the second face of the media pack passes through media to provide filtration of the fluid; wherein
the fluted sheet and facing sheet formed of multi-layer media comprising a polytetrafluoroethylene (PTFE) layer supported by a polymeric scrim layer; and
wherein the polymeric scrim layer has an external maximum peak height S P , measured between a highest peak and a mean plane, of less than 5μ.
2. The filtration media pack of claim 1 , wherein the polymeric scrim layer has an external root mean square height S q , of less than 40μ according to the formula:
Sq
=
1
A
∫
∫
A
z
2
(
x
,
y
)
dxdy
wherein A is area of the polymeric scrim layer measured, x and y are coordinates within a plane formed by the polymeric scrim layer, and z is elevation perpendicular to the plane formed by the polymeric scrim layer.
3. The filtration media pack of claim 1 , wherein the polymeric scrim layer has an external root mean square height S q , of less than 20μ according to the formula:
Sq
=
1
A
∫
∫
A
z
2
(
x
,
y
)
dxdy
wherein A is area of the polymeric scrim layer measured, x and y are coordinates within a plane formed by the polymeric scrim layer, and z is elevation perpendicular to the plane formed by the polymeric scrim layer.
4. The filtration media pack of claim 1 , wherein the polymeric scrim layer has an external arithmetical mean height S a of less than 60μ according to the following formula:
Sa
=
1
A
∫
∫
A
❘
"\[LeftBracketingBar]"
z
(
x
,
y
)
❘
"\[RightBracketingBar]"
dxdy
wherein A is area of the polymeric scrim layer measured, x and y are coordinates within a plane formed by the polymeric scrim layer, and z is elevation perpendicular to the plane formed by the polymeric scrim layer.
5. The filtration media pack of claim 1 , wherein the polymeric scrim layer has an external arithmetical mean height S a of less than 30μ
Sa
=
1
A
∫
∫
A
❘
"\[LeftBracketingBar]"
z
(
x
,
y
)
❘
"\[RightBracketingBar]"
dxdy
wherein A is area of the polymeric scrim layer measured, x and y are coordinates within a plane formed by the polymeric scrim layer, and z is elevation perpendicular to the plane formed by the polymeric scrim layer.
6. The filtration media pack of claim 1 , wherein the polymeric scrim layer has an external arithmetical mean height S a of less than 20μ
Sa
=
1
A
∫
∫
A
❘
"\[LeftBracketingBar]"
z
(
x
,
y
)
❘
"\[RightBracketingBar]"
dxdy
wherein A is area of the polymeric scrim layer measured, x and y are coordinates within a plane formed by the polymeric scrim layer, and z is elevation perpendicular to the plane formed by the polymeric scrim layer.
7. The filtration media pack of claim 1 , wherein the polymeric scrim layer has fibers having a mean diameter of 10 to 20 μ and a standard deviation of less than 3 μ.
8. The filtration media pack of claim 1 , wherein the polymeric scrim layer has fibers having a mean diameter of 12 to 18 μ and a standard deviation of less than 2 μ.
9. The filtration media pack of claim 1 , wherein the polymeric scrim layer has fibers having a index of distribution of −1 to −0.5 as measured by the following formula:
Index
of
Dispersion
,
I
d
=
σ
2
μ
wherein σ 2 is variance of dispersion and u is mean dispersion.
10. The filtration media pack of claim 1 , wherein the multi-layer media has air permeability of greater than 4.0 cubic feet per minute (CFM).
11. The filtration media pack of claim 1 , wherein the filter pack has an efficiency of 99.97 percent of 3 micron particles at a face velocity of 10 feet per minute.
12. The filtration media pack of claim 1 , wherein the multi-layer media has a thickness of less than 20 mils.
13. The filtration media pack of claim 1 , wherein the polymeric scrim comprises spunbond fibers.
14. The filtration media pack of claim 13 , wherein the spunbond fibers comprise polyester fibers.
15. The filtration media pack of claim 1 , wherein the polymeric scrim layer has a basis weight of less than 2.0 ounces per square yard.
16. The filtration media pack of claim 1 , wherein the polymeric scrim layer has a frazier air permeability of greater than 900 cfm/ft 2 at 0.5 inches of water.
17. The filtration media pack of claim 1 , wherein the PTFE has a basis weight of 1.5 to 2.5 ounces per square yard.
18. The filtration media pack of claim 1 , wherein the PTFE has a basis weight of less than 3.0 ounces per square yard.
19. A filtration media pack comprising:
(a) a plurality of layers of single facer media wherein the layers of single facer media comprise a fluted sheet, a facing sheet, and a plurality of flutes extending between the fluted sheet and the facing sheet and having a flute length extending from a first face of the filtration media pack to a second face of the filtration media pack;
(b) a first portion of the plurality of flutes being closed to unfiltered fluid flowing into the first portion of the plurality of flutes, and a second portion of the plurality of flutes being closed to unfiltered fluid flowing out of the second portion of the plurality of flutes so that fluid passing into one of the first face or the second face of the media pack and out the other of the first face or the second face of the media pack passes through media to provide filtration of the fluid; wherein
the fluted sheet and facing sheet formed of multi-layer media comprising a polytetrafluoroethylene (PTFE) layer supported by a polymeric scrim layer; and
wherein the polymeric scrim layer has an external root mean square height S q , of less than 40μ according to the formula:
Sq
=
1
A
∫
∫
A
z
2
(
x
,
y
)
dxdy
wherein A is area of the polymeric scrim layer measured, x and y are coordinates within a plane formed by the polymeric scrim layer, and z is elevation perpendicular to the plane formed by the polymeric scrim layer.
20. A filtration media pack comprising:
(a) a plurality of layers of single facer media wherein the layers of single facer media comprise a fluted sheet, a facing sheet, and a plurality of flutes extending between the fluted sheet and the facing sheet and having a flute length extending from a first face of the filtration media pack to a second face of the filtration media pack;
(b) a first portion of the plurality of flutes being closed to unfiltered fluid flowing into the first portion of the plurality of flutes, and a second portion of the plurality of flutes being closed to unfiltered fluid flowing out of the second portion of the plurality of flutes so that fluid passing into one of the first face or the second face of the media pack and out the other of the first face or the second face of the media pack passes through media to provide filtration of the fluid; wherein
the fluted sheet and facing sheet formed of multi-layer media comprising a polytetrafluoroethylene (PTFE) layer supported by a polymeric scrim layer
wherein the polymeric scrim layer has fibers having a index of distribution of −1 to −0.5 as measured by the following formula:
Index
of
Dispersion
,
I
d
=
σ
2
μ
wherein σ 2 is variance of dispersion and u is mean dispersion.