Claims
- 1. A filter assembly comprising a filter house having an inlet and an outlet that can pass a gaseous medium; a frame within the filter housing capable of dividing the housing into a first section and a second section, a series of flexible filter bags comprising a filter fabric substrate comprising an elongated filter surface, the frame comprising sealing means connecting the flexible bags to the frame ensuring that the gaseous medium passes through the flexible filter bag within the housing; associated with each said flexible bag, means to prevent the bags from collapsing under the influence of the gaseous stream moving through the housing and means, in a section of the housing, to pass a gaseous stream through the housing and through the flexible bags; wherein each flexible bag is at least partially covered by a layer comprising a polymeric fine fiber with a diameter of about 0.01 to about 0.5 micron.
- 2. The assembly of claim 1 wherein after test exposure for a test period of 16 hours to test conditions of 140° F. air and a relative humidity of 100% retains greater than 30% of the fiber unchanged for filtration purposes.
- 3. The assembly of claim 1 wherein the polymer comprises and addition polymer.
- 4. The assembly of claim 1 wherein the polymer comprises a condensation polymer.
- 5. The assembly of claim 3 wherein the polymer comprises and addition polymer and an additive.
- 6. The assembly of claim 4 wherein the polymer comprises a condensation polymer and an additive.
- 7. The assembly of claim 5 wherein the additive is hydrophobic.
- 8. The assembly of claim 6 wherein the additive is hydrophobic.
- 9. The assembly of claim 3 wherein the addition polymer comprises a polyvinyl halide polymer.
- 10. The assembly of claim 3 wherein the addition polymer comprises a polyvinylidene halide polymer or mixtures thereof.
- 11. The assembly of claim 10 wherein the polyvinylidene halide comprises polyvinylidene chloride.
- 12. The assembly of claim 10 wherein the polyvinylidene halide comprises polyvinylidene fluoride.
- 13. The assembly of claim 2 wherein the addition polymer comprises a polyvinylalcohol.
- 14. The assembly of claim 13 wherein the addition polymer comprises a copolymer.
- 15. The assembly of claim 13 wherein the polyvinylalcohol is crosslinked with about 1 to 40 wt. % of a crosslinking agent.
- 16. The assembly of claim 15 wherein the crosslinked polyvinylalcohol is crosslinked using a polyacrylic acid having a molecular weight of about 1000 to 3000.
- 17. The assembly of claim 15 wherein the crosslinked polyvinylalcohol is crosslinked using a melamine-formaldehyde resin having a molecular weight of about 1000 to 3000.
- 18. The assembly of claim 3 wherein the condensation polymer comprises a nylon and an additive.
- 19. The assembly of claim 18 wherein the additive comprises a resinous oligomer having a molecular weight of about 500 to 3000 and an aromatic character wherein the additive miscible in the condensation polymer.
- 20. The assembly of claim 18 wherein the polymeric fiber comprises a nylon polymer, other than a copolymer formed from a cyclic lactam and a C6-10 diamine monomer or a C6-10 diacid monomer, and an additive.
- 21. The assembly of claim 20 wherein the additive comprises a resinous composition comprising an oligomer having a molecular weight of about 500 to 3000 and an alkyl phenolic aromatic character wherein the additive miscible in the condensation polymer.
- 22. The assembly of claim 4 wherein the condensation polymer comprises a nylon polymer, and a resinous additive comprising an oligomer having a molecular weight of about 500 to 3000 and an aromatic character wherein the additive miscible in the condensation polymer.
- 23. The assembly of claim 3 wherein the condensation polymer comprises a polyalkylene terephthalate.
- 24. The assembly of claim 23 wherein the condensation polymer comprises a polyalkylene naphthalate.
- 25. The assembly of claim 24 wherein the condensation polymer comprises a polyethylene terephthalate.
- 26. The assembly of claim 4 wherein the condensation polymer comprises a nylon polymer comprising a homopolymer having repeating units derived from a cyclic lactam.
- 27. The assembly of claim 26 wherein the nylon copolymer is combined with a second nylon polymer, the second nylon polymer differing in molecular weight or monomer composition.
- 28. The assembly of claim 18 wherein the nylon copolymer is combined with a second nylon polymer.
- 29. The assembly of claim 28 wherein the second nylon polymer comprises an alkoxy alkyl modified polyamide.
- 30. The assembly of claim 28 wherein the polymers are treated to form a single polymeric composition as measured by a differential scanning calorimeter showing a single phase material.
- 31. The assembly of claim 30 wherein the copolymer and the second polymer are heat treated.
- 32. The assembly of claim 31 wherein the copolymer and the second polymer are heat treated to a temperature less than the lower melting point of the first or the second polymers.
- 33. The assembly of claim 4 wherein the additive comprises an oligomer comprising tertiary butyl phenol.
- 34. The assembly of claim 33 wherein the additive comprises an oligomer comprising:
- 35. The assembly of claim 4 wherein the additive comprises an oligomer comprising bis-phenol A.
- 36. The assembly of claim 35 wherein the additive comprises an oligomer comprising:
- 37. The assembly of claim 4 wherein the additive comprises an oligomer comprising dihydroxy biphenyl.
- 38. The assembly of claim 37 wherein the additive comprises an oligomer comprising:
- 39. The assembly of claim 4 wherein the additive comprises a blend of the resinous additive and a fluoropolymer.
- 40. The assembly of claim 4 wherein the additive comprises a fluorocarbon surfactant.
- 41. The assembly of claim 4 wherein the additive comprises a nonionic surfactant.
- 42. The assembly of claim 4 wherein the condensation polymer comprises a polyurethane polymer.
- 43. The assembly of claim 4 wherein the condensation polymer comprises a blend of a polyurethane polymer and a polyamide polymer.
- 44. The assembly of claim 43 wherein the polyamide polymer comprises a nylon.
- 45. The assembly of claim 18 wherein the nylon comprises a nylon homopolymer, a nylon copolymer or mixtures thereof.
- 46. The assembly of claim 4 wherein the condensation polymer comprises an aromatic polyamide.
- 47. The assembly of claim 4 wherein the condensation polymer comprises a reaction product of a diamine monomer and poly(m-phenylene isophthalamide).
- 48. The assembly of claim 46 wherein the polyamide comprises a reaction product of a diamine and a poly(p-phenylene terephthalamide).
- 49. The assembly of claim 4 wherein the condensation polymer comprises a polybenzimidazole.
- 50. The assembly of claim 4 wherein the condensation polymer comprises a polyarylate.
- 51. The assembly of claim 50 wherein the polyarylate polymer comprises a condensation polymerization reaction product between bis-phenol-A and mixed phthalic acids.
- 52. The assembly of claim 1 wherein the flexible bag comprises a filter tube having an open end and a closed end, said open end having a seal, the gaseous stream exiting from the interior of the section and the layer of fine fiber having a basis weight of about 0.0005 to 0.2 milligram per square centimeter of the exterior portion of the tubular section.
- 53. The assembly of claim 52 wherein the filter tube comprises a woven fabric.
- 54. The assembly of claim 52 wherein the filter tube comprises a non-woven fabric.
- 55. The assembly of claim 52 wherein the filter tube section comprises a polyester fiber.
- 56. The assembly of claim 52 wherein the filter tube comprises a cotton fiber.
- 57. The assembly of claim 52 wherein the filter can pass about 5 to about 15 cubic feet per minute of gaseous media per square foot of filter media.
- 58. The assembly of claim 52 wherein there are about 10 to about 100 filter tubes in the housing.
- 59. The assembly of claim 52 wherein the filter tube comprises a layer of fine fiber on the upstream surface of the filter tube and a second layer of fine fiber on the exit surface of the filter tube.
- 60. The assembly of claim 52 wherein the layer of fine fiber has a thickness of about 0.1 to about 3 microns and has a basis weight of about 0.001 to 0.1 milligram per square centimeter.
- 61. A bag house filter apparatus comprising:
(a) a housing defining an interior, an inlet, and an outlet; (b) a frame mounted within the housing interior; (c) at least two filter bags mounted on and sealed against said frame;
(i) each of said filter bags having an exterior, upstream surface and an interior, downstream surface defining an interior volume; each of the filter bags having a clean air opening communicating with the interior volume;
(A) each filter bag exterior surface having uniformly deposited thereon a fine fiber layer at a basis weight of about 0.0005 to 0.2 mg-cm−2; and (d) a blower arrangement to move an air stream through the housing inlet, through the filter bags from the upstream surface to the downstream surface into the interior volume and then exit the interior volume through the clean air opening, and through the housing outlet.
- 62. An apparatus according to claim 61 wherein:
(a) each of the filter bags is rectangular, with substantially parallel walls.
- 63. An apparatus according to claim 61 wherein:
(a) each of the filter bags is tube-shaped.
- 64. An apparatus according to claim 61 wherein:
(a) each of the filter bags comprises a woven fabric.
- 65. An apparatus according to claim 61 wherein:
(a) each of the filter bags comprises a non-woven fabric.
- 66. An apparatus according to claim 61 wherein:
(a) each of the filter bags comprises a polyester fiber.
- 67. An apparatus according to claim 61 wherein:
(a) each of the filter bags comprises a cotton fiber.
- 68. An apparatus according to claim 61 wherein:
(a) the filter apparatus can pass about 5 to about 15 cubic feet per minute of gaseous media per square foot of filter media.
- 69. An apparatus according to claim 61 wherein:
(a) there are about 10 to about 100 filter bags in the housing.
- 70. An apparatus according to claim 61 wherein:
(a) each of the filter bags comprises a layer of fine fiber on the upstream surface of each of the filter bags and a second layer of fine fiber on the exit surface of each of the filter bags.
- 71. An apparatus according to claim 61 wherein:
(a) the layer of fine fiber has a thickness of about 0.1 to about 3 microns and has a basis weight of about 0.001 to 0.1 milligram per square centimeter.
- 72. A method of filtering an air stream containing a particulate comprising the steps of placing an air filtration bag within a filter housing having an air inlet and an air outlet, said filter housing comprising a frame support within the housing dividing the housing into two section, a clean section and a dirty section, the housing and frame comprising a series of flexible filter bags of an air pervious material, each including a substantially open upper end and a seal to the frame, sealing members secured to at least one of the filter bags maintaining the separation between the clean section and the dirty section, air pervious means within said bags to prevent the bags from collapsing and means in one section of the housing to cause air to pass through the bags; and passing the air through the filter bags to ensure that the particulate is removed from the air stream said filter bag having an exterior surface and an interior surface, the exterior surface having uniformly deposited thereon a fine fiber layer at a basis weight of about 0.0005 to 0.2 mg-cm−2, said air passing into the bag and exiting the interior surface.
- 73. The method of claim 72 wherein the filtration method includes a pulse cleaning step wherein dust forming on the exterior of the bag is removed by a short reversal of the air flow resulting in a substantially reduced pressure drop.
- 74. The method of claim 72 wherein the filtration method includes a mechanical vibratory cleaning of the bag wherein dust forming on the exterior of the bag is removed by a vibration resulting in a substantially reduced pressure drop.
- 75. A method of making a filter bag, the steps comprising:
(a) forming a layer of fine fiber on a bag fabric, the fiber having a diameter of about 0.01 to 0.5 microns and a basis weight of about 0.0005 to 0.2 mg-cm−2, said layer having a thickness of less than about 0.3 microns forming a fiber and fabric; and (c) assembling the fiber and fabric into a bag.
- 76. The method of claim 75 wherein a step of heat treating the fiber and fabric for a period of time effective increases the adhesion of the fiber to the fabric forming an adhered fiber and fabric.
- 77. The method of claim 76 wherein the heat treating step is performed after the bag is assembled.
- 78. The method of claim 75 wherein in step (b) the adhered fiber and fabric is made into the form of a roll of adhered fiber and fabric and the adhered fiber and fabric is unrolled, cut and sewn into the bag.
- 79. The method of claim 75 wherein the fiber is electrospun onto a woven fabric.
- 80. The method of claim 76 wherein the fiber and fabric are heat treated at a temperature less than the lower melting point of the polymer.
- 81. The method of claim 75 wherein the layer of fine fiber is formed on the substrate by laminating a preformed fine fiber layer.
- 82. The assembly of claim 52 wherein the fine fiber is covered with a layer that prevents abrasion of the fine fiber layer.
- 83. The assembly of claim 53 wherein the layer that prevents abrasion comprises a scrim with a basis weight of about 0.2 to 2 oz.-yd−2.
- 84. The assembly of claim 52 wherein the filter tube comprises a layer of fine fiber on the exit surface of the filter tube.
- 85. The assembly of claim 52 wherein the filter tube comprises a layer of fine fiber on the upstream surface of the filter tube and a second layer of fine fiber on the exit surface of the filter tube.
- 86. The assembly of claim 52 wherein the layer of fine fiber has a thickness of about 0.1 to about 3 microns and has a basis weight of about 0.001 to 0.1 milligram per square centimeter.
RELATED APPLICATION
[0001] This application claims priority under 35 U.S.C. § 119(e) to U.S. provisional application Ser. No. 60/230,138, filed on Sep. 5, 2000, incorporated by reference herein.
Provisional Applications (1)
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Number |
Date |
Country |
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60230138 |
Sep 2000 |
US |