Self-supporting pleated filter media

• US 20060005517A1
• Filed: 07/09/2004
• Published: 01/12/2006
• Est. Priority Date: 07/09/2004
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Christensen, Lowell E., Young, Donald E., Duffy, Dean R., Sundet, Douglas C.
• Granted Patent: US 7,896,940 B2
• Time in Patent Office: Days
• US Class Current: 55/497
• CPC Class Codes: B01D 46/0001 Making filtering elements
• 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 46/523 with means for maintaining spacing between the pleats or folds

Abstract

The present invention is a filter that includes a length of filter media and a continuous, substantially nonlinear adhesive strand. The filter media has a front face and a rear face. The filter media has a plurality of pleats defined by a plurality of fold lines, each fold line being intermediate oppositely sloping first and second wall surfaces. The plurality of fold lines comprise a first plurality of pleat tips and a second plurality of pleat valleys. The adhesive strand is provided on the front face of the filter media in discontinuous contact with the filter media. The adhesive strand contacts the filter media at a pleat tip and contacts the filter media at a portion of a first wall surface and contacts the filter media at a portion of a second wall surface.

Claims

1. A filter comprising:

a length of filter media having a front face and a rear face, the filter media having a plurality of pleats defined by a plurality of fold lines, each fold line being intermediate oppositely sloping first and second wall surfaces, wherein the plurality of fold lines comprise a first plurality of pleat tips and a second plurality of pleat valleys; and

a continuous, substantially nonlinear adhesive strand provided on the front face of the filter media in discontinuous contact with the filter media, wherein the adhesive strand contacts the filter media at a pleat tip and contacts the filter media at a portion of a first wall surface and contacts the filter media at a portion of a second wall surface.

2. The filter of claim 1 wherein the filter media comprises a laminate material.

3. The filter of claim 1 wherein the filter media comprises a nonwoven polymeric material.

4. The filter of claim 3 wherein the nonwoven polymeric material comprises an electret material.

5. The filter of claim 1 wherein the adhesive strand does not contact the filter media in a valley.

6. The filter of claim 1 wherein the adhesive strand contacts the filter media along a majority of a length of each wall surface.

7. The filter of claim 1 wherein a distance between a pleat tip and an adjacent pleat tip is between about 1.8 mm and about 12.6 mm.

8. The filter of claim 1 wherein a distance between a pleat tip and an adjacent pleat tip is between about 3.6 mm and about 27.0 mm.

9. The filter of claim 1 wherein a distance between a pleat tip and an adjacent pleat tip defines a pleat spacing, and wherein a ratio between pleat spacing and pleat height and is between about 0.1 and about 0.7.

10. The filter of claim 1 wherein a distance between a pleat tip and an adjacent pleat tip defines a pleat spacing, and wherein a ratio between pleat spacing and pleat height and is between about 0.2 and about 1.5.

11. The filter of claim 1 wherein a portion of the adhesive strand on a first wall surface contacts a portion of the adhesive strand on a second wall surface.

12. The filter of claim 1, further comprising a plurality of continuous adhesive strands.

13. The filter of claim 12, wherein the plurality of adhesive strands are positioned parallel to, and spaced apart from, each other.

14. The filter of claim 13, wherein an adhesive strand is spaced from an adjacent adhesive strand by between about 2.5 cm and about 12.7 cm.

15. The filter of claim 1 wherein the filter media further comprises a side edge, the side edge being substantially normal to a direction of the fold line, the filter media further comprising:

a side band reinforcement strip disposed on the side edge.

16. The filter of claim 1 further comprising:

a tip band reinforcement strip disposed on the second plurality of pleat valleys.

17. The filter of claim 1 wherein the filter media further comprises a pair of opposite side edges and a pair of opposite end edges, the filter media further comprising:

a frame member positioned at each edge.

18. The filter of claim 17 wherein each frame member comprises a U-shaped channel which covers an edge and at least a portion of each of the front face and the rear face.

19. The filter of claim 1 further comprising:

a reinforcing member provided in contact with the rear face of the filter media.

20. The filter of claim 19 wherein the reinforcing member is substantially planar.

21. The filter of claim 20 wherein the planar reinforcing member is adhered to the rear face of the filter media.

22. The filter of claim 21 wherein the planar reinforcing member is a metal mesh scrim.

23. The filter of claim 1 wherein the adhesive strand comprises a hot-melt adhesive.

24. The filter of claim 1 in which the adhesive strand is disposed substantially normal to a direction of a fold line.

25. A filter comprising:

a length of filter media having a front face and a rear face, wherein the filter media comprises a nonwoven polymeric material, the filter media having a plurality of pleats defined by a plurality of fold lines, each fold line being intermediate oppositely sloping first and second wall surfaces, wherein the plurality of fold lines comprise a first plurality of pleat tips and a second plurality of pleat valleys; and

a continuous, substantially nonlinear adhesive strand provided on the front face of the filter media in continuous contact with the filter media, wherein the adhesive strand contacts the filter media at a pleat tip and contacts the filter media at a portion of a first wall surface and contacts the filter media at a portion of a second wall surface.

26. The filter of claim 25 wherein a distance between a pleat tip and an adjacent pleat tip is between about 1.8 mm and about 12.6 mm.

27. The filter of claim 25 wherein a distance between a pleat tip and an adjacent pleat tip is between about 3.6 mm and about 27.0 mm.

28. The filter of claim 25 wherein a distance between a pleat tip and an adjacent pleat tip defines a pleat spacing, and wherein a ratio between pleat spacing and pleat height and is between about 0.1 and about 0.7.

29. The filter of claim 25 wherein a distance between a pleat tip and an adjacent pleat tip defines a pleat spacing, and wherein a ratio between pleat spacing and pleat height and is between about 0.2 and about 1.5.

30. The filter of claim 25 wherein a portion of the adhesive strand on a first wall surface contacts a portion of the adhesive strand on a second wall surface.

31. The filter of claim 25, further comprising a plurality of continuous adhesive strands.

32. The filter of claim 31, wherein the plurality of adhesive strands are positioned parallel to, and spaced apart from, each other.

33. The filter of claim 32, wherein an adhesive strand is spaced from an adjacent adhesive strand by between about 2.5 cm and about 12.7 cm.

34. The filter of claim 25 wherein the filter media further comprises a side edge, the side edge being substantially normal to a direction of the fold line, the filter media further comprising:

a side band reinforcement strip disposed on the side edge.

35. The filter of claim 25 further comprising:

a tip band reinforcement strip disposed on the second plurality of pleat valleys.

36. The filter of claim 25 wherein the filter media further comprises a pair of opposite side edges and a pair of opposite end edges, the filter media further comprising:

a frame member positioned at each edge.

37. The filter of claim 36 wherein each frame member comprises a U-shaped channel which covers an edge and at least a portion of each of the front face and the rear face.

38. The filter of claim 25 further comprising:

a reinforcing member provided in contact with the rear face of the filter media.

39. The filter of claim 38 wherein the reinforcing member is substantially planar.

40. The filter of claim 39 wherein the planar reinforcing member is adhered to the rear face of the filter media.

41. The filter of claim 40 wherein the planar reinforcing member is a metal mesh scrim.

42. The filter of claim 25 wherein the adhesive strand comprises a hot-melt adhesive.

43. The filter of claim 25 in which the adhesive strand is disposed substantially normal to a direction of a fold line.

44. A pleated filter comprising:

a folded filter media of nonwoven polymeric material, the filter media having a front face and a rear face, the filter media having a plurality of fold lines, each fold line being intermediate oppositely sloping first and second wall surfaces, wherein the plurality of fold lines comprise a first plurality of pleat tips and a second plurality of pleat valleys, wherein a distance between a pleat tip and an adjacent pleat tip is between about 4 mm and about 7 mm, the filter media further comprising a pair of opposite side edges and a pair of opposite end edges;

a plurality of continuous, substantially nonlinear adhesive strands provided on the front face of the filter media in discontinuous contact with the filter media;

wherein an adhesive strand contacts the filter media at a pleat tip, contacts the filter media along a majority of a length of each wall surface, and does not contact the filter media in a valley;

wherein the plurality of strands are positioned parallel to, and spaced about 5.1 cm apart from, each other;

a metal mesh scrim adhered to the rear face of the filter media; and

a frame member positioned at each edge, wherein each frame member comprises a U-shaped channel which covers an edge and at least a portion of each of the front face and the rear face.