Claims
- 1. A green uncured pre-form for an exhaust aftertreatment filter, said pre-form comprising first and second sheets of regenerable filter media, said second sheet having a plurality of pleats defined by wall segments extending in zig-zag manner between pleat tips at axially extending bend lines, the pleat tips on one side of said second sheet being in contiguous relation with said first sheet, said flow channels having a lateral cross-sectional shape comprising two adjacent included angles each greater than 45° and less than 75°.
- 2. The pre-form according to claim 1 wherein said wall segments have a thickness less than 0.8 mm, a porosity greater than 80%, and an extension between pleat tips less than 10 mm.
- 3. The pre-form according to claim 2 wherein said media comprises a high temperature composite ceramic filter media comprising a plurality of haphazardly arranged ceramic fibers.
- 4. The pre-form according to claim 3 wherein the fibers have a length in the range of 0.01 to 10.0 mm and an average diameter in the range of 1 to 20 microns.
- 5. The pre-form according to claim 3 wherein the ceramic fibers are high purity alumina having less than 5% silica and other impurities.
- 6. The pre-form according to claim 2 wherein said media comprises a mixture of haphazardly arranged ceramic fibers and organic fibers and a thermoplastic resin bonding said fibers together.
- 7. The pre-form according to claim 6 wherein said media comprises 50% to 80% by weight ceramic fibers, 10% to 50% by weight organic fibers, and 2% to 20% by weight thermoplastic resin.
- 8. The pre-form according to claim 7 wherein said media has a porosity of 80% to 95% and a mean flow pore diameter of 5 to 15 microns.
- 9. The pre-form according to claim 6 wherein ceramic fibers comprise high purity alumina.
- 10. The pre-form according to claim 6 wherein said organic fibers comprise a combination of wood fibers and fibrillated organic fibers.
- 11. The pre-form according to claim 10 wherein the fibrillated fibers comprise aramid resin pulp.
- 12. The pre-form according to claim 2 wherein each of said sheets comprises a plurality of haphazardly arranged ceramic fibers, and comprising an inorganic binder bonding the pleat tips of said second sheet to said first sheet.
- 13. The pre-form according to claim 12 wherein each of said sheets further comprises a plurality of organic fibers and a thermoplastic resin bonding said fibers together.
- 14. The pre-form according to claim 2 wherein said pre-form has less than 20% by weight incinerable material.
- 15. The pre-form according to claim 2 wherein each of said first and second sheets of said pre-form has greater than 80% by weight of fibers selected from the group consisting of ceramic fibers and inorganic fibers.
- 16. The pre-form according to claim 2 wherein each of said first and second sheets has a thickness less than 0.5 mm.
- 17. The pre-form according to claim 2 wherein each of said first and second sheets has a porosity greater than 85%.
- 18. The pre-form according to claim 2 wherein said wall segments have an extension along said second sheet between pleat tips less than 6 mm.
- 19. The pre-form according to claim 1 wherein said two adjacent included angles comprise a first angle between said first sheet and a first said wall segment of said second sheet, and a second angle between first sheet and a second said wall segment of said second sheet, each of said first and second angles being greater than 45° and less than 75°.
- 20. The pre-form according to claim 19 wherein said lateral cross-sectional shape of said flow channels consists of three pleat tips and three included angles, namely said first angle, said second angle, and a third angle between said first and second wall segments.
- 21. The pre-form according to claim 20 wherein said lateral cross-sectional shape is an isosceles triangle and wherein
- 22. The pre-form according to claim 19 wherein said lateral cross-sectional shape of said flow channels consists of four pleat tips and four included angles.
- 23. The pre-form according to claim 22 wherein said lateral cross-sectional shape comprises an isosceles trapezoid.
- 24. The pre-form according to claim 23 wherein said trapezoid has two acute angles equal to each other, two obtuse angles equal to each other, and two sides of equal length.
- 25. The pre-form according to claim 22 wherein said lateral cross-sectional shape comprises a trapezoid having first and second distally opposite sides slanted towards each other and having distally opposite substantially parallel major and minor bases extending laterally between said sides, said major base being longer than said minor base, said first wall segment of said second sheet providing said first side of said trapezoid, said second wall segment of said second sheet providing said second side of said trapezoid, said first sheet providing said major base of said trapezoid, said second sheet having a truncated wall segment spanning said first and second wall segments and providing said minor base of said trapezoid, the ratio of the length of said minor base to the length of said major base being less than 0.27.
- 26. The pre-form according to claim 25 wherein said sheets are wound in a spiral, and said flow channel lateral cross-sectional trapezoid shape consists of four walls, namely a first wall provided by said first sheet along said major base, a second wall provided by said first wall segment of said second sheet along said first side, a third wall provided by said truncated wall segment of said second sheet along said minor base and by a section of the next layer of said first sheet in said spiral pattern along said minor base, and a fourth wall provided by said second wall segment of said second sheet along said second side, said first, second and fourth walls have a single sheet thickness, said third wall has a double sheet thickness, the single sheet thickness of said first wall being provided by said first sheet and being less than 0.8 mm, the single sheet thickness of said second wall being provided by said second sheet and being less than 0.8 mm, the double sheet thickness of said third wall being provided by said first and second sheets and being less than 1.6 mm, the single sheet thickness of said fourth wall being provided by said second sheet and being less than 0.8 mm, wherein said first and second walls meet at a first of said pleat tips and define said first angle, said second and third walls meet at a second of said pleat tips and define a third of said angles, said third and fourth walls meet at a third of said pleat tips and define a third of said angles, said fourth and first walls meet at a fourth of said pleat tips and define said second angle, said first angle at said pleat tip is greater than 45° and less than 75°, said third angle at said second pleat tip is greater than 90°, said fourth angle at said third pleat tip is greater than 90°, said second angle at said fourth pleat tip is greater than 45° and less than 75°, and wherein the length of said second wall between said first and second pleat tips is less than 10 mm, and the length of said fourth wall between said third and fourth pleat tips is less than 10 mm.
- 27. The pre-form according to claim 22 wherein said lateral cross-sectional shape comprises a trapezoid having first and second distally opposite sides slated towards each other and having distally opposite substantially parallel major and minor bases extending laterally between said sides, said major base being longer than said minor base, said first wall segment of said second sheet providing said first side of said trapezoid, said second wall segment of said second sheet providing said second side of said trapezoid, said first sheet providing said major base of said trapezoid, said second sheet having a truncated wall segment spanning said first and second wall segments and providing said minor base of said trapezoid, wherein
- 28. The pre-form according to claim 2 wherein said sheets of said pre-form are rollable into a spiral.
- 29. The pre-form according to claim 2 wherein said sheets of said pre-form are curable and rigidizable to an exhaust aftertreatment filter for filtering engine exhaust flowing axially therethrough, said filter being regenerable by heat to burn-off contaminant particulate from said engine exhaust.
- 30. The pre-form according to claim 29 wherein said pre-form is rigidizable with sol-gel.
- 31. The pre-form according to claim 29 wherein said pre-form is rigidizable with chemical vapor infiltration.
- 32. The pre-form according to claim 29 wherein said pre-form is rigidizable with ceramic bond phase.
- 33. The pre-form according to claim 29 wherein said pre-form is rigidizable with silicon carbide.
- 34. The pre-form according to claim 2 wherein said wall segments are alternately sealed to each other by a first upstream set of plugs to define a first set of flow channels closed by said plugs, and a second set of flow channels interdigitated with said first set of flow channels and having open upstream ends, said wall segments being alternately sealed to each other by a second downstream set of plugs closing said second set of flow channels, said first set of flow channels having open downstream ends.
- 35. A method of making a green uncured pre-form for an exhaust aftertreatment filter, comprising providing first and second sheets of regenerable filter material, forming a plurality of pleats in said second sheet defined by wall segments extending in zig-zag manner between pleat tips at axially extending bend lines, bonding the pleat tips on one side of said second sheet to said first sheet to define axial flow channels, forming said flow channels having a lateral cross-sectional shape comprising two adjacent included angles greater than 45° and less than 75°.
- 36. The method according to claim 35 comprising providing said wall segments with a thickness less than 0.8 mm, a porosity greater than 80%, and an extension between pleat tips less than 10 mm.
- 37. The method according to claim 35 comprising providing each of said first and second sheets of high temperature composite ceramic filter media comprising a plurality of haphazardly arranged ceramic fibers.
- 38. The method according to claim 37 wherein said ceramic fibers have a length in the range of 0.01 to 10.0 mm and an average diameter in the range of 1 to 20 microns.
- 39. The method according to claim 38 wherein said ceramic fibers are high purity alumina having less than 5% silica and other impurities.
- 40. The method according to claim 35 wherein each of said sheets comprises 50% to 80% by weight ceramic fibers, 10% to 50% by weight organic fibers, and 2% to 20% by weight thermoplastic resin.
- 41. The method according to claim 35 wherein each of said first and second sheets has a porosity of 80% to 95% and a mean flow pore diameter of 5 to 15 microns.
- 42. The method according to claim 35 comprising rolling said sheets into a spiral.
- 43. The method according to claim 35 further comprising curing and rigidizing said pre-form to an exhaust aftertreatment filter for filtering engine exhaust flowing axially therethrough, said filter being regenerable by heat to burn-off contaminant particulate from said engine exhaust.
- 44. The method according to claim 43 comprising rigidizing said pre-form with sol-gel.
- 45. The method according to claim 43 comprising rigidizing said pre-form with chemical vapor infiltration.
- 46. The method according to claim 43 comprising rigidizing said pre-form with ceramic bond phase.
- 47. The method according to claim 43 comprising rigidizing said pre-form with silicon carbide.
- 48. The method according to claim 35 comprising alternately sealing said wall segments to each other by a first upstream set of plugs to define a first set of flow channels closed by said plugs, and a second set of flow channels interdigitated with said first set of flow channels and having open upstream ends, and alternately sealing said wall segments to each other by a second downstream set of plugs closing said second set of flow channels, said first set of flow channels having open downstream ends.
- 49. Forming apparatus for forming a green uncured pre-form for an exhaust aftertreatment filter, said pre-form comprising first and second sheets of regenerable filter media, said second sheet having a plurality of pleats defined by wall segments extending in zig-zag manner between pleat tips at axially extending bend lines, the pleat tips on one side of said second sheet being in contiguous relation with said first sheet and defining axial flow channels, said flow channels having a lateral cross-sectional shape comprising two adjacent included angles each greater than 45° and less than 75°, said forming apparatus comprising first and second star gears each having a plurality of teeth interdigitated with a plurality of roots therebetween, said gears rotating in intermeshed relation with the tooth of one gear in the root of the other gear, said gears passing said second sheet therebetween, said gears gathering and folding said second sheet along crease lines at said pleat tips, said crease lines providing said axially extending bend lines.
- 50. The forming apparatus according to claim 49 wherein said wall segments have a thickness less than 0.8 mm, a porosity greater than 80%, and an extension between pleat tips less than 10 mm,
- 51. The forming apparatus according to claim 49 wherein each said root has a given arcuate length along an inner hub surface spanning between and separating a respective pair of teeth having sides extending generally radially outwardly from opposite arcuate ends of said spanning root hub surface, a first of said sides meeting said spanning root hub surface at a first arcuate end thereof at a first angle at a first junction point, a second of said sides meeting said spanning root hub surface at a second arcuate end thereof at a second angle at a second junction point, said first and second junction points being spaced from each other by said given arcuate length.
- 52. The forming apparatus according to claim 51 wherein each of said first and second angles is greater than 90°.
- 53. The forming apparatus according to claim 51 wherein each tooth of at least one of said gears has an outer end with a pointed tip extending into a respective root and spaced from said first junction point by a first triangular shaped gap, and spaced from said second junction point by a second triangular shaped gap.
- 54. The forming apparatus according to claim 51 wherein each tooth of both of said gears has an outer end with a pointed tip extending into a respective root and spaced from said first junction point by a first triangular shaped gap, and spaced from said second junction point by a second triangular shaped gap.
- 55. The forming apparatus according to claim 51 wherein each tooth of one of said gears has an outer end with first and second pointed tips extending into a respective root.
- 56. The forming apparatus according to claim 55 wherein each tooth of the other of said gears has an outer end with a pointed tip extending into a respective root and spaced from said first junction point by a first triangular shaped gap, and spaced from said second junction point by a second triangular shaped gap.
- 57. The forming apparatus according to claim 55 wherein said given arcuate length defines a minor base, said first and second sides diverge from each other as they extend outwardly from said spanning root hub surface and are spaced from each other at their outer ends along a second given arcuate length defining a major base, and wherein the ratio of the length of said minor base to the length of said major base is less than 0.27.
- 58. The forming apparatus according to claim 49 wherein each said tooth has an outer end and a pair of convexly bowed sides extending from said outer end generally radially inwardly to respective roots spaced on opposite sides of the tooth.
- 59. The forming apparatus according to claim 49 comprising a pair of parallel guide bars spaced on opposite sides of the intermeshing of said gears, said bars extending parallel to the direction of travel of said second sheet through said gears, said bars being spaced from each other by a gap less than 10 mm along a direction perpendicular to said travel direction and perpendicular to the gear rotation axis, said bars receiving said pleats and engaging said pleat tips.
- 60. The forming apparatus according to claim 59 wherein said second sheet is fed forwardly through said gears from an inlet region to an outlet region, said guide bars have upstream ends at said gears, and downstream ends at said outlet region and spaced from said gears.
- 61. The forming apparatus according to claim 60 wherein said gears rotate about respective rotation axes, and said upstream ends of said guide bars are upstream of said rotation axes.
- 62. The forming apparatus according to claim 49 wherein said wall segments are alternately sealed to each other by a first upstream set of plugs to define a first set of flow channels closed by said plugs, and a second set of flow channels interdigitated with said first set of flow channels and having open upstream ends, and said wall segments are alternately sealed to each other by a second downstream set of plugs closing said second set of flow channels, said first set of flow channels having open downstream ends.
- 63. A method of configuring and shaping a green uncured pre-form for an exhaust aftertreatment filter, said pre-form comprising first and second sheets of regenerable filter material, said second sheet having a plurality of pleats defined by wall segments extending in zig-zag manner between pleat tips at axially extending bend lines, the pleat tips on one side of said second sheet being in contiguous relation with said first sheet and defining axial flow channels, said flow channels having a lateral cross-sectional shape comprising two adjacent included angles each greater than 45° and less than 75°, said method comprising feeding said second sheet through first and second star gears each having a plurality of teeth interdigitated with a plurality of roots therebetween, rotating said gears in intermeshed relation with the tooth of one gear in the root of the other gear, gathering and folding said second sheet through said gears along crease lines at said pleat tips, said crease lines providing said axially extending bend lines.
- 64. The method according to claim 63 comprising providing said wall segments having a thickness less than 0.8 mm, a porosity greater than 80%, and an extension between pleat tips less than 10 mm.
- 65. The method according to claim 63 comprising feeding said second sheet through said gears to a pair of guide bars, spacing said guide bars on opposite sides of the intermeshing of said gears.
- 66. The method according to claim 65 comprising extending said guide bars parallel to the direction of travel of said second sheet through said gears, spacing said guide bars from each other by a gap less than 10 mm along a direction perpendicular to said travel direction and perpendicular to the gear rotation axis, and receiving said pleats and engaging said pleat tips with said guide bars.
- 67. The method according to claim 66 comprising feeding said second sheet forwardly through said gears from an inlet region to an outlet region, providing said guide bars with upstream ends at said gears, and downstream ends at said outlet region and spaced from said gears.
- 68. The method according to claim 63 comprising alternately sealing said wall segments to each other by a first upstream set of plugs to define a first set of flow channels closed by said plugs, and a second set of flow channels interdigitated with said first set of flow channels and having open upstream ends, and alternately sealing said wall segments to each other by a second downstream set of plugs closing said second set of flow channels, said first set of flow channels having open downstream ends.
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. patent application Ser. No. 09/573,747, filed May 18, 2000.
Continuation in Parts (1)
|
Number |
Date |
Country |
Parent |
09573747 |
May 2000 |
US |
Child |
09935847 |
Aug 2001 |
US |