Air filter assembly with a permeable baffle

1. An air filter assembly comprising:

a housing comprising an outer wall with a substantially cylindrical inner surface, an inlet, and an outlet, the inlet positioned along and extending through the outer wall, the outlet positioned along and extending through an axial end of the housing;

a filter element comprising a filter media with a substantially cylindrical outer surface, the filter element positionable within the housing; and

a permeable baffle positioned between the inlet and the filter element, the permeable baffle allowing at least some air to flow therethrough, the permeable baffle comprising a permeable material defining openings with an average size between 20 and 400 μm.

2. The air filter assembly of claim 1 , wherein the permeable baffle covers the entire outer surface of the filter media.

3. The air filter assembly of claim 1 , wherein the permeable baffle covers only a portion of the outer surface of the filter media.

4. The air filter assembly of claim 1 , wherein the permeable baffle is permanently fixed to one of the housing or the filter element.

5. The air filter assembly of claim 1 , wherein the permeable baffle is removably attachable to the housing or the filter element.

6. The air filter assembly of claim 1 , further comprising a cover removably attachable to the housing, the permeable baffle permanently fixed to the cover.

7. The air filter assembly of claim 1 , further comprising a cover removably attachable to the housing, the permeable baffle removably attachable to the cover.

8. The air filter assembly of claim 1 , wherein the permeable baffle includes a support frame, the permeable material being attached to or integrated with the support frame.

9. An air filter assembly comprising:

a housing comprising an outer wall, an inlet, and an outlet, the housing containing a filter element, the outer wall comprising a substantially cylindrical inner surface that incoming air flow from the inlet flows substantially tangential to, the outlet positioned along and extending through an axial end of the housing; and

a permeable baffle positioned within the housing between the inlet and the filter element and shielding at least a portion of the filter element from the incoming air flow through the inlet, the permeable baffle comprising a permeable material defining openings with an average size between 20 and 400 μm.

10. The air filter assembly of claim 9 , further comprising the filter element, the filter element comprising a closed axial end, an open axial end, and a filter media extending axially between the closed axial end and the open axial end, wherein the open axial end of the filter element is fluidly connected to and sealed with the outlet of the housing.

11. The air filter assembly of claim 9 , wherein the inlet is offset from a centerline of the housing such that the inlet is closer to one axial end of the housing than the other axial end.

12. The air filter assembly of claim 9 , wherein the permeable baffle is substantially cylindrical.

13. The air filter assembly of claim 9 , wherein the permeable material is a woven mesh.

14. The air filter assembly of claim 9 , wherein the permeable material is an extruded mesh.

15. The air filter assembly of claim 9 , wherein the permeable material is a non-woven filtration media with a basis weight of the fibers between 0.2 to 2 oz/yd 2 and a Frazier permeability between 100 and 2,000 ft/min.

16. The air filter assembly of claim 9 , wherein the permeable baffle is permanently fixed to the housing.

17. The air filter assembly of claim 9 , wherein the permeable baffle is removably attachable to the housing.

18. An air filter assembly comprising:

a housing comprising an outer wall, an inlet, and an outlet, the housing containing a filter element, the outer wall comprising a substantially cylindrical inner surface that incoming air flow from the inlet flows substantially tangential to,

the housing comprising a first axial end and a second axial end, the outlet positioned along and extending through the axial end of the housing, the second axial end of the housing substantially open;

a cover attachable to the second axial end of the housing such that the cover covers the second axial end; and

a permeable baffle positioned within the cover in order to be positioned between the inlet and the filter element and to shield at least a portion of the filter element from the incoming air flow through the inlet, the permeable baffle comprising a permeable material defining openings with an average size between 20 and 400 μm.

19. The air filter assembly of claim 18 further comprising the filter element, the filter element comprising a closed axial end, an open axial end, and a filter media extending axially between the closed axial end and the open axial end, wherein the open axial end of the filter element is fluidly connected to and sealed with the outlet of the housing.

20. The air filter assembly of claim 18 , wherein the inlet is offset from a centerline of the housing such that the inlet is closer to one axial end of the housing than the other axial end.

21. The air filter assembly of claim 18 , wherein the permeable material is a woven mesh.

22. The air filter assembly of claim 18 , wherein the permeable material is an extruded mesh.

23. The air filter assembly of claim 18 , wherein the permeable material is a non-woven filtration media with a basis weight of the fibers between 0.2 to 2 oz/yd 2 and a Frazier permeability between 100 and 2,000 ft/min.

24. The air filter assembly of claim 18 , wherein the permeable baffle is permanently fixed to the filter media.

25. The air filter assembly of claim 18 , wherein the permeable baffle is removably attachable to the filter media.

26. An air filter element comprising:

a filter media for filtering air; and

a permeable baffle attachable to the filter media and shielding at least a portion of the filter media, the permeable baffle comprising a permeable material defining openings with an average size between 20 and 400 μm, the permeable baffle covering only a portion of an outer surface of the filter media.

27. The air filter element of claim 26 , wherein the permeable material is a woven mesh.

28. The air filter element of claim 26 , wherein the permeable material is an extruded mesh.

29. The air filter element of claim 26 , wherein the permeable material is a non-woven filtration media with a basis weight of the fibers between 0.2 to 2 oz/yd 2 and a Frazier permeability between 100 and 2,000 ft/min.

30. The air filter element of claim 26 , wherein the filter media is substantially cylindrical and the permeable baffle extends around at least a portion of a curved outer surface of the filter media.

31. The air filter element of claim 26 , wherein the permeable baffle is directly attachable to the filter media.

32. The air filter element of claim 26 , further comprising an endcap attached to one end of the filter media, wherein the permeable baffle is directly attachable to the endcap.

33. The air filter element of claim 26 , wherein the permeable baffle allows at least some air to flow therethrough.

34. The air filter element of claim 26 , wherein the permeable baffle is permanently fixed to the filter media.

35. The air filter element of claim 26 , wherein the permeable baffle includes a support frame, the permeable material being attached to or integrated with the support frame.

36. An air filter element comprising:

a filter media for filtering air; and

a permeable baffle attachable to the filter media and shielding at least a portion of the filter media, the permeable baffle comprising a permeable material defining openings with an average size between 20 and 400 μm, wherein the permeable baffle is removably attachable to the filter media.