Filtration media pack, filter elements, and air filtration media

1. A filtration media pack comprising:

(a) a plurality of layers of single face media comprising a fluted sheet, a facing sheet, and a plurality of flutes extending between the fluted sheet and the facing sheet;

(b) a first portion of the plurality of flutes being closed to unfiltered air flowing into the first portion of the plurality of flutes, and a second portion of the plurality of flutes being closed to unfiltered air flowing out of the second portion of the plurality of flutes, such that air 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 air; and

wherein at least one of the flutes comprises at least one contact region between the single face media and the fluted sheet, the contact region comprising at least one permeable protrusion extending from at least one of the facing sheet and fluted sheet.

2. The filtration media pack of claim 1 , wherein the protrusion comprises an island.

3. The filtration media pack of claim 1 , wherein the protrusions have a height of from 0.2 to 3 millimeters.

4. The filtration media pack of claim 1 , wherein the protrusions have a height of from 0.4 to 24 times the thickness of the media forming the fluted sheet.

5. The filtration media pack of claim 1 , wherein the protrusions are from 10 to 90 percent of the height of the flutes in the fluted sheet.

6. The filtration media pack of claim 1 , wherein the protrusions are less than 30 percent of the height of the flutes in the fluted sheet.

7. The filtration media pack of claim 1 , wherein the protrusions are at least 15 percent of the height of the flutes in the fluted sheet.

8. The filtration media pack of claim 1 , wherein the protrusions are from 1 to 20 percent of the width of the flutes in the fluted sheet.

9. The filtration media pack of claim 1 , wherein the protrusions are less than 10 percent of the width of the flutes in the fluted sheet.

10. The filtration media pack of claim 1 , wherein the protrusions are at least 5 percent of the width of the flutes in the fluted sheet.

11. A filtration media pack comprising:

(a) a plurality of layers of single face media wherein the layer of single face media comprising 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 air flowing into the first portion of the plurality of flutes, and a second portion of the plurality of flutes being closed to unfiltered air flowing out of the second portion of the plurality of flutes so that air passing into one of the first face or the second face of the media pack and out the other of the first face of the second face of the media pack passes through media to provide filtration of the air; and

(c) wherein the fluted sheet comprises:

(i) repeating internal peaks facing toward the facing sheet and repeating external peaks facing away from the facing sheet; and

(ii) a repeating pattern of flutes comprising at least one ridge extending along at least a portion of the flute length between adjacent peaks, and

(iii) a plurality of permeable protrusions extending from the flute and contacting the facing sheet, wherein at least one of the plurality of protrusions is located between a ridge and a peak of the flute.

12. The filtration media pack of claim 11 , wherein the plurality of protrusions comprise islands.

13. The filtration media pack of claim 11 , wherein the repeating pattern of flutes comprises a protrusion on either side of the peak.

14. The filtration media pack of claim 11 , wherein the protrusions are located between the ridge and the peak.

15. The filtration media pack of claim 11 , wherein the protrusions are tapered with respect to each other.

16. The filtration media pack of claim 11 , wherein the protrusions have a height of from 0.2 to 3 millimeters.

17. The filtration media pack of claim 11 , wherein the protrusions have a height of from 0.4 to 24 times the thickness of the media forming the fluted sheet.

18. The filtration media pack of claim 11 , wherein the protrusions are from 10 to 90 percent of the height of the flutes in the fluted sheet.

19. The filtration media pack of claim 11 , wherein the protrusions are at least 15 percent of the height of the flutes in the fluted sheet.

20. A filtration media pack comprising:

(a) a plurality of layers of single face media comprising a fluted sheet, a facing sheet, and a plurality of flutes extending between the fluted sheet and the facing sheet;

(b) a first portion of the plurality of flutes being closed to unfiltered air flowing into the first portion of the plurality of flutes, and a second portion of the plurality of flutes being closed to unfiltered air flowing out of the second portion of the plurality of flutes, such that air 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 air; and

wherein the fluted sheet comprises a plurality of permeable protrusions, the protrusions covering only a portion of the fluted sheet.