Filter and method of filtering a fluid

• US 6,391,200 B2
• Filed: 10/05/1999
• Issued: 05/21/2002
• Est. Priority Date: 10/05/1998
• Status: Expired due to Term

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: Cuno Incorporated
• Inventors: Hamlin, Thomas J., Sale, Richard, Pulek, John L., Paul, C. Thomas
• Primary Examiner(s): Savage, Matthew O.
• Assistant Examiner(s): Ocampo, Marianne S.
• Application Number:
  US09/412,419
• Publication Number:
  US 20010037982A1
• Time in Patent Office: 959 Days
• Field of Search: 210/488-489, 210/492, 210/484, 210/497.01, 210/497.1, 210/483, 210/335, 210/499, 210/490, 210/437, 210/457, 554/85--86, 555/20, 555/27
• US Class Current: 210/497.1
• CPC Class Codes: B01D 2239/0618 Non-woven
• CPC Class Codes: B01D 2239/0622 Melt-blown
• CPC Class Codes: B01D 2239/0627 Spun-bonded
• CPC Class Codes: B01D 2239/065 More than one layer present in the filtering material apparatus incorporating such gas filtering material B01D2275/10
• CPC Class Codes: B01D 2239/0654 Support layers
• CPC Class Codes: B01D 2239/0663 The layers being joined by hydro-entangling
• CPC Class Codes: B01D 2239/0668 The layers being joined by heat or melt-bonding
• CPC Class Codes: B01D 2239/069 Special geometry of layers
• CPC Class Codes: B01D 2239/0695 Wound layers apparatus incorporating such gas filtering material B01D2275/105
• CPC Class Codes: B01D 2239/1291 Other parameters
• CPC Class Codes: B01D 25/24 Cell-type roll filters
• CPC Class Codes: B01D 29/111 Making filtering elements
• CPC Class Codes: B01D 29/216 with wound sheets
• CPC Class Codes: B01D 39/083 of organic material
• CPC Class Codes: B01D 39/086 of inorganic material
• CPC Class Codes: B01D 39/1623 of synthetic origin
• CPC Class Codes: B01D 39/1692 Other shaped material, e.g. perforated or porous sheets
• CPC Class Codes: B01D 39/18 the material being cellulose or derivatives thereof cork or peat B01D39/1646 ; making filter paper D21F11/14
• CPC Class Codes: B01D 63/06 Tubular membrane modules
• CPC Class Codes: B01D 63/103 Details relating to membrane envelopes
• CPC Class Codes: B01D 69/12 : Composite membranes; Ultra-thin membranes

Abstract

A spiral wound filter element is disclosed which includes alternating layers of filter medium and diffusion medium wrapped about a cylindrical core defining a central axis of the filter element. The alternating layers extend from a radially innermost layer of the filter element to a radially outermost layer of the filter element, the diffusion medium is defined by a continuous lengthwise sheet of mesh material, and the filter medium is defined by at least one sheet of filter material arranged along the length of the continuous sheet of mesh material. The alternating layers of filter medium and diffusion medium define three distinct radially disposed layered filtering sections surrounding the cylindrical core, and include a first filtering section having radially outer prequalifying layers, a second filtering section having middle prequalifying layers and a third filtering section having radially inner qualifying layers. The radially outer prequalifying layers and the middle prequalifying layers define about two-thirds of the radial distance from the radially outermost layer of the filter element to the radially innermost layer of the filter element.

Claims

1. A spiral wound filter element comprising:

alternating layers of filter medium and diffusion medium wrapped about a cylindrical core defining a central axis of the filter element, the alternating layers extending from a radially innermost layer of the filter element to a radially outmost layer of the filter element, the diffusion medium defined by a continuous lengthwise sheet of mesh material, the filter medium defined by at least one sheet of filter material arranged along the length of the continuous sheet of mesh material, the alternating layers of filter medium and diffusion medium defining three distinct radially disposed layered filtering sections surrounding the cylindrical core, including a fist filtering section having radially outer prequalifying layers, a second filtering section having middle prequalifying layers and a third filtering section having radially inner qualifying layers, the radially outer prequalifying layers and the middle prequalifying layers defining about two-thirds of the radial distance from the radially outermost layer of the filter element to the radially innermost layer of the filter element, wherein;

a) the filter material within the radially outer prequalifying layers includes a number of perforations forming radially extending by-pass apertures;

b) the filter material within the middle prequalifying layers includes a fewer number of perforations forming radially extending by-pass apertures than a perforated sheet of the radially outer prequalifying layers; and

c) the first material within the radially inner qualifying layers is imperforate.

2. A spiral wound filter element as recited in claim 1, wherein the filter medium is defined by a plurality of discrete sheets of filter material arranged along the length of the continuous sheet of mesh material.

3. A spiral wound filter element as recited in claim 2, wherein the radially inner qualifying layers include at least one imperforate sheet of filter material.

4. A spiral wound filter element as recited in claim 2, wherein the middle prequalifying layers include at least one perforated sheet of filter material.

5. A spiral wound filter element as recited in claim 2, wherein the radially outer prequalifying layers include at least one perforated sheet of filter material.

6. A spiral wound filter element as recited in claim 2, wherein each sheet of filter material has a consistent pore size.

7. A spiral wound filter element as recited in claim 2, wherein each sheet of filter material has a consistent fiber geometry.

8. A spiral wound filter element as recited in claim 2, wherein sheets of filter material have different pore sizes.

9. A spiral wound filter element as recited in claim 2, wherein sheets of filter material have different fiber geometries.

10. A spiral wound filter element as recited in claim 1, wherein the alternating layers of filter medium and diffusion medium are wrapped about a perforated cylindrical core.

11. A spiral wound filter element as recited in claim 10, wherein an innermost portion of the diffusion medium is wrapped at least once around the core to form an inner layer of diffusion medium.

12. A spiral wound filter element as recited in claim 1, wherein the diffusion medium is defined by a continuous lengthwise sheet of extruded polymeric mesh material.

13. A spiral wound filter element as recited in claim 12, wherein the extruded polymeric mesh material is a bi-planar mesh material.

14. A spiral wound filter element as recited in claim 1, wherein the filter material within the outer prequalifying layers has about twice as many perforations as the filter material within the middle prequalifying layers.

15. A spiral wound filter element as recited in claim 1, wherein an outermost portion of the diffusion medium is wrapped at least once around the outermost layer of the filter element to form an outer layer of diffusion medium.

16. A spiral wound filter element comprising:

alternating layers of filter medium and diffusion medium wrapped about a cylindrical core defining a central axis of the filter element, the alternating layers extending from a radially innermost layer of the filter element to a radially outermost layer of the filter element, the diffusion medium defined by a continuous lengthwise sheet of mesh material, the filter medium defined by a plurality of discrete sheets of filter material arranged along the length of the continuous sheet of mesh material, the alternating layers of filter medium and diffusion medium defining three distinct radially disposed layered filtering sections, including a first filtering section having radially outer prequalifying layers, a second filtering section having middle prequalifying layers and a third filtering section having radially inner qualifying layers, wherein;

a) the radially outer prequalifying layers include at least one perforated sheet of filter material having a number of perforations forming radially extending by-pass apertures;

b) the middle prequalifying layers include at least one perforated sheet of filter material having a fewer number of perforations forming radially extending by-pass apertures than a perforated sheet of the radially outer prequalifying layers; and

c) the radially inner qualifying layers include at least one imperforate sheet of filter material.

17. A spiral wound filter element as recited in claim 16, wherein the alternating layers of filter medium and diffusion medium are wrapped about a perforated cylindrical core.

18. A spiral wound filter element as recited in claim 17, wherein an innermost portion of the diffusion medium is wrapped at least once around the core to form an inner layer of diffusion medium.

19. A spiral wound filter element as recited in claim 16, wherein the diffusion medium is defined by a continuous lengthwise sheet of extruded polymeric mesh material.

20. A spiral wound filter element as recited in claim 19, wherein the extruded polymeric mesh material is a bi-planar mesh material.

21. A spiral wound filter element as recited in claim 16, wherein the radially inner qualifying layers define about one-third of the radial distance from the radially innermost layer of the filter element to the radially outermost layer of the filter element.

22. A spiral wound filter element as recited in claim 21, wherein the radially outer prequalifying layers and the middle prequalifying layers define about two-thirds of the radial distance from the radially outermost layer of the filter element to the radially innermost layer of the filter element.

23. A spiral wound filter element as recited in claim 16, wherein a perforated sheet of the outer prequalifying layers has about twice as many perforations as a perforated sheet of the middle prequalifying layers.

24. A spiral wound filter element as recited in claim 16, wherein the radially inner qualifying layers include two imperforate sheets of filter material.

25. A spiral wound filter element as recited in claim 16, wherein the middle prequalifying layers include two perforated sheets of filter material.

26. A spiral wound filter element as recited in claim 16, wherein the radially outer prequalifying layers include two perforated sheets of filter material.

27. A spiral wound filter element as recited in claim 16, wherein each sheet of filter material has a consistent pore size.

28. A spiral wound filter element as recited in claim 16, wherein each sheet of filter material has a consistent fiber geometry.

29. A spiral wound filter element as recited in claim 16, wherein sheets of filter material have different pore sizes.

30. A spiral wound filter element as recited in claim 16, wherein sheets of filter material have different fiber geometries.

31. A spiral wound filter element as recited in claim 16, wherein an outermost portion of the diffusion medium is wrapped at least once around the outermost layer of the filter element to form an outer layer of diffusion medium.

32. A spiral wound filter element comprising:

alternating layers of filter medium and diffusion medium wrapped about a cylindrical core defining a central axis of the filter element, the alternating layers extending from a radially innermost layer of the filter element to a radially outermost layer of the filter element, the diffusion medium defined by a continuous lengthwise sheet of bi-planar mesh material, the filter medium defined by a plurality of discrete sheets of filter material arranged along the length of the continuous sheet of mesh material, the alternating layers of filter medium and diffusion medium defining three distinct radially disposed layered filtering sections, including a first filtering section having radially outer prequalifying layers, a second filtering section having middle prequalifying layers and a third filtering section having radially inner qualifying layers, wherein;

a) the radially outer prequalifying layers include two perforated sheets of filter material each having a number of perforations forming radially extending by-pass apertures;

b) the middle prequalifying layers include two perforated sheets of filter material each having a fewer number of perforations forming radially extending by-pass apertures than the perforated sheets of the radially outer prequalifying layers; and

c) the radially inner qualifying layers include two imperforate sheets of filter material.

33. A spiral wound filter element as recited in claim 32, wherein the perforated sheets of the outer prequalifying layers have about twice as many perforations as the perforated sheets of the middle prequalifying layers.

34. A spiral wound filter element as recited in claim 33, wherein the alternating layers of filter medium and diffusion medium are wrapped about a perforated cylindrical core.

35. A spiral wound filter element as recited in claim 34, wherein an innermost portion of the diffusion medium is wrapped at least once around the core to form an inner layer of diffusion medium.

36. A spiral wound filter element as recited in claim 33, wherein the radially inner qualifying layers define about one-third of the radial distance from the radially innermost layer of the filter element to the radially outermost layer of the filter element.

37. A spiral wound filter element as recited in claim 33, wherein the radially outer prequalifying section and the middle prequalifying section define about two-thirds of the radial distance from the radially outermost layer of the filter element to the radially innermost layer of the filter element.

38. A spiral wound filter element as recited in claim 33, wherein each sheet of filter material has a consistent pore size and a consistent fiber geometry.

39. A spiral wound filter element as recited in claim 33, wherein sheets of filter material have different pore sizes.

40. A spiral wound filter element as recited in claim 33, wherein sheets of filter material have different fiber geometries.

41. A spiral wound filter element as recited in claim 33, wherein an outermost portion of the diffusion medium is wrapped at least once around the outermost layer of the filter element to form an outer layer of diffusion medium.

42. A spiral wound filter element as recited in claim 33, wherein the bi-planar mesh material is defined by a continuous lengthwise sheet of extruded polymeric mesh material.