FILTER ELEMENT AND METHOD

• US 20090044702A1
• Filed: 02/21/2008
• Published: 02/19/2009
• Est. Priority Date: 02/22/2007
• Status: Active Grant

• Current Assignee: Donaldson Company Incorporated
• Original Assignee: Donaldson Company Incorporated
• Inventors: Ouyang, Ming, Moreau, Egide Emmanuel Paul Baudry, Adamek, Daniel E., Cappuyns, Jan, Rogers, Robert M.
• Granted Patent: US 8,021,455 B2
• Time in Patent Office: Days
• US Class Current: 95/287
• CPC Class Codes: B01D 2239/0216 Bicomponent or multicomponent fibres
• CPC Class Codes: B01D 2239/0258 comprising nanoparticles
• CPC Class Codes: B01D 2239/064 The fibres being mixed
• CPC Class Codes: B01D 2239/0681 The layers being joined by gluing
• CPC Class Codes: B01D 2275/10 Multiple layers
• CPC Class Codes: B01D 39/163 sintered or bonded
• CPC Class Codes: B01D 39/2024 otherwise bonded, e.g. by resins
• CPC Class Codes: B01D 46/003 including coalescing means for the separation of liquid
• CPC Class Codes: B01D 46/10 Particle separators, e.g. dust precipitators, using filter plates, sheets or pads having plane surfaces
• CPC Class Codes: B01D 46/546 using nano- or microfibres
• CPC Class Codes: F02M 35/024 using filters, e.g. moistened F02M35/026 takes precedence; cleaning of the filtering material F02M35/08
• CPC Class Codes: Y10S 55/05 Methods of making filter

Abstract

A filter element having multiple formed layers of filtration media is disclosed. The media are layered so as to form a pore size gradient. The filter element is capable of removing both solid and liquid particulates from a moving fluid stream. The filter element has high strength and compressibility. The layers can be supported on a porous or perforate support to provide mechanical stability during filtering operations. The filtration media layers can be formed into various filter element forms such as panels, cartridges, inserts, and the like.

Claims

1. A filter element comprising at least two layers of a nonwoven filter media, the filter element comprising

(a) a first filter medium comprising 1 to 100 wt % of a first fiber comprising a bicomponent fiber comprising a diameter of 5 to 50 microns, and 5 to 50 wt % of a second fiber, wherein the first filter medium has a pore size of 0.2 to 200 micrometers, a permeability of 1 to 1000 ft-min⁻

1, a solidity of about 2 to 25% at 860 Pa, a basis weight of 5 to 1000 g-m<sup>−

2</sup>, and a compressibility of 0.5 to 1.0 between 860 Pa and 3860 Pa; and

(b) a second filter medium that is different from the first filter medium and comprising a pore size of 0.2 to 200 micrometers, a permeability of 1 to 1000 ft-min<sup>−

1</sup>, a solidity of about 2 to 25% at 860 Pa, a basis weight of 5 to 1000 g-m<sup>−

2</sup>, and a compressibility of about 0.5 to 1.0 between 860 Pa and 3860 Pa,

wherein the filter element is capable of filtering both solid and liquid particulates from a heavily loaded fluid stream.

2. The filter element of claim 1 further comprising media layers on a support.

3. The filter element of claim 2 wherein the support comprises a housing.

4. The filter element of claim 2 wherein the support is perforate.

5. The filter element of claim 1 comprising multiple layers of the first medium.

6. The filter element of claim 1 comprising multiple layers of the second medium.

7. The filter element of claim 1 further comprising a third medium.

8. The filter element of claim 7 comprising multiple layers of the third medium.

9. The filter element of claim 1, wherein the solid particulate comprises smoke, soot, talc, asbestos, carbon, a solid nanoparticle, or combinations thereof.

10. The filter element of claim 9 wherein the solid particulate comprises soot.

11. The filter element of claim 1 wherein the liquid particulate comprises water, a fuel, an oil, a hydraulic fluid, an emulsion, an aerosols of a hydrophobic or a hydrophilic material, a volatile organic chemical, or combinations thereof.

12. The filter element of claim 11 wherein the liquid particulate comprises an oil.

13. The filter element of claim 1 wherein the liquid particulate coalesces on, and drains away from, the filter media

14. The filter element of claim 1 wherein the fluid stream comprises air, industrial waste gases, crankcase gases, blow-by gases, nitrogen, helium, argon, or combinations thereof.

15. The filter element of claim 14 wherein the fluid stream comprises air.

16. The filter element of claim 1 comprising a gradient of pore sizes.

17. The filter element of claim 1 wherein the solid particulate is trapped substantially by the first filter medium and the liquid particulate is trapped substantially by the second filter medium.

18. The filter element of claim 1 wherein the second fiber comprises a glass.

19. The filter element of claim 1 wherein the second fiber comprises a polyester.

20. The filter element of claim 1 wherein the first filter media comprises a third fiber.

21. The filter element of claim 1 wherein the second filter media comprises a bicomponent fiber.

22. The filter element of claim 19 further comprising a glass fiber.

23. The filter element of claim 20 wherein the third fiber comprises a polyester fiber.

24. The filter element of claim 1 wherein the compressibility of the element is greater than about 0.7 over a pressure differential of about 860 to about 3860 Pa.

25. The filter element of claim 1 wherein the pore size of the first filter medium is about 4 to 200 microns.

26. The filter element of claim 1 wherein the pore size of the first filter medium is about 50 to 150 microns.

27. The filter element of claim 1 wherein the permeability of the first filter medium is from about 50 to 800 ft-min⁻

1.

28. The filter element of claim 1 wherein the permeability of the first filter medium is from about 140 to 460 ft-min⁻

1.

29. The filter element of claim 1 wherein the solidity of the first filter medium is from about 2 to 10% at 860 Pa.

30. The filter element of claim 1 wherein the solidity of the first filter medium is from about 3 to 8% at 860 Pa.

31. The filter element of claim 1 wherein the basis weight of the first filter medium is from about 50 to 500 g-m⁻

2.

32. The filter element of claim 1 wherein the basis weight of the first filter medium is from about 150 to 350 g-m⁻

2.

33. The filter element of claim 1 wherein the bicomponent fiber of the first filter medium comprises a diameter of about 10 to 30 microns.

34. The filter element of claim 1 wherein the second fiber of the first filter medium comprises a diameter of about 0.1 to 50 microns.

35. The filter element of claim 1 wherein the second fiber of the first filter medium comprises a diameter of about 0.5 to 30 microns.

36. The filter element of claim 1 wherein the first filter medium comprises a thickness of about 0.05 to 22 millimeter at 860 Pa.

37. The filter element of claim 1 wherein the first filter medium comprises a thickness of about 0.5 to 11 millimeter at 860 Pa.

38. The filter element of claim 1 wherein the first filter medium comprises a thickness of about 1 to 5 millimeter at 860 Pa.

39. The filter medium of claim 1 wherein the first filter medium comprises a compressibility of about 0.7 to 1.0 between 860 Pa and 3860 Pa.

40. The filter element of claim 1 wherein the pore size of the second filter medium is about 4 to 200 microns.

41. The filter element of claim 1 wherein the pore size of the second filter medium is about 40 to 70 microns.

42. The filter element of claim 1 wherein the permeability of the second filter medium is from about 50 to 800 ft-min⁻

1.

43. The filter element of claim 1 wherein the permeability of the second filter medium is from about 350 to 650 ft-min⁻

1.

44. The filter element of claim 1 wherein the solidity of the second filter medium is from about 2 to 10% at 860 Pa.

45. The filter element of claim 1 wherein the solidity of the second filter medium is from about 5 to 8% at 860 Pa.

46. The filter element of claim 1 wherein the basis weight of the second filter medium is from about 20 to 120 g-m⁻

2.

47. The filter element of claim 1 wherein the basis weight of the second filter medium is from about 30 to 50 g-m⁻

2.

48. The filter element of claim 1 wherein the second filter medium comprises a thickness of about 0.05 to 22 millimeter at 860 Pa.

49. The filter element of claim 1 wherein the second filter medium comprises a thickness of about 0.3 to 3.6 millimeter at 860 Pa.

50. The filter element of claim 1 wherein the second filter medium comprises a thickness of about 0.5 to 0.8 millimeter at 860 Pa.

51. The filter medium of claim 1 wherein the first filter medium comprises a compressibility of about 0.7 to 1.0 between 860 Pa and 3860 Pa.

52. The filter element of claim 1 wherein one or more filter media comprise a surface treatment agent selected from the group consisting of a silicone, a fluorochemical, an amphoteric molecule, or mixtures thereof.

53. A method of making a layered filter element comprising at least two media layers, the method comprising the steps of

(a) forming a first filter medium layer comprising the steps of

(i) assembling at least a bicomponent fiber and a second fiber by an air laid technique;

(ii) condensing the assembly of fibers;

(iii) heating the condensed assembly of fibers to form a first filter medium comprising a pore size of 0.2 to 200 micrometers, a permeability of 1 to 1000 ft-min<sup>−

1</sup>, a solidity of about 2 to 25% at 860 Pa, a basis weight of 5 to 1000 g-m<sup>−

2</sup>, and a compressibility of 0.5 to 1.0 between 860 Pa and 3860 Pa;

(b) forming a second filter medium layer that is different from the first filter medium layer, the second filter medium layer comprising a pore size of 0.2 to 200 micrometers, a permeability of 1 to 1000 ft-min<sup>−

1</sup>, a solidity of about 2 to 25% at 860 Pa, a basis weight of 5 to 1000 g-m<sup>−

2</sup>, and a compressibility of about 0.5 to 1.0 between 860 Pa and 3860 Pa.

54. The method of claim 53 wherein the second filter medium is made using a wet laid technique.

55. The method of claim 53 wherein the first filter medium and the second filter medium are cut into a shape prior to forming the layered element.

56. The method of claim 55 wherein the layered element is contained within a support.

57. The method of claim 56 wherein the support is apertured.

58. The method of claim 53 further comprising a third medium.

59. The method of claim 53 wherein the filter media are layered so as to comprise a gradient of pore sizes.

60. The method of claim 53 further comprising treating the first or second filter media with a surface treatment agent.

61. The method of claim 60 wherein the surface treatment agent is selected from the group consisting of a silicone, a fluorochemical, an amphoteric molecule, or mixtures thereof.

62. A method of filtering particles from a fluid stream comprising the steps of

(a) contacting a heavily particulate loaded fluid stream with a filter element, the filter element comprising

(i) a first filter medium layer comprising 1 to 100 wt % of a first fiber comprising a bicomponent fiber comprising a diameter of 5 to 50 microns, and 5 to 50 wt % of a second fiber, wherein the first filter medium layer has a pore size of 0.2 to 200 micrometers, a permeability of 1 to 1000 ft-min⁻

1, a solidity of about 2 to 25% at 860 Pa, a basis weight of 5 to 1000 g-m<sup>−

2</sup>, and a compressibility of 0.5 to 1.0 between 860 Pa and 3860 Pa; and

(ii) a second filter medium layer that is different from the first filter medium, the second filter medium layer comprising a pore size of 0.2 to 200 micrometers, a permeability of 1 to 1000 ft-min<sup>−

1</sup>, a solidity of about 2 to 25% at 860 Pa, a basis weight of 5 to 1000 g-m<sup>−

2</sup>, and a compressibility of about 0.5 to 1.0 between 860 Pa and 3860 Pa; and

(b) retaining a particulate in the filter element.

63. The method of claim 62 wherein the filter element retains at least two different types of particulates.

64. The method of claim 63 wherein the different types of particulates comprise particles having different average particle sizes.

65. The method of claim 63 wherein the two types of particles comprise a solid particle and a liquid particle.

66. The method of claim 65 wherein the solid particulate comprises smoke, talc, asbestos, carbon, a solid nanoparticle, or combinations thereof.

67. The method of claim 65 wherein the solid particulate comprises soot.

68. The method of claim 65 wherein the liquid particulate comprises water, a fuel, a hydraulic fluid, an emulsion, an aerosol of a hydrophobic or a hydrophilic material, a volatile organic chemical, or combinations thereof.

69. The method of claim 65 wherein the liquid particulate comprises an oil.

70. The method of claim 65 wherein the retained liquid particulate further coalesces on, and drains away from, the filter media

71. The method of claim 62 wherein the fluid stream comprises air, industrial waste gases, blow-by gases, nitrogen, helium, argon, or combinations thereof.

72. The method of claim 62 wherein the fluid stream comprises crankcase gas.

73. The method of claim 65 wherein the solid particulate is trapped substantially by the first filter medium and the liquid particulate is trapped substantially by the second filter medium.