Pleated filter element

• US 6,315,130 B1
• Filed: 01/07/2000
• Issued: 11/13/2001
• Est. Priority Date: 01/07/1999
• Status: Expired due to Term

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: Cuno Incorporated (3M Company)
• Inventors: Olsen, Daniel K.
• Primary Examiner(s): Savage, Matthew O.
• Application Number:
  US09/479,686
• Time in Patent Office: 676 Days
• Field of Search: 210/487, 210/489, 210/490, 210/491, 210/493.1, 210/493.2, 210/493.5, 555/21
• US Class Current: 210/490
• CPC Class Codes: B01D 2201/0407 Perforated supports on both sides of the filtering element
• CPC Class Codes: B01D 2201/122 with pleats of different length
• CPC Class Codes: B01D 2275/10 Multiple layers
• CPC Class Codes: B01D 27/06 with corrugated, folded or wound material
• CPC Class Codes: B01D 29/111 Making filtering elements
• CPC Class Codes: B01D 29/21 with corrugated, folded or wound sheets
• CPC Class Codes: B01D 29/58 arranged concentrically or coaxially
• CPC Class Codes: B01D 46/2411 Filter cartridges
• CPC Class Codes: B01D 46/522 with specific folds, e.g. having different lengths

Abstract

A filter element according to the present disclosure includes a plurality of longitudinally extending pleats including outwardly radiating primary pleats and inwardly radiating secondary pleats, with at least one secondary pleat positioned between two adjacent primary pleats. Each primary pleat has a predetermined radial height, and each secondary pleat has a radial height that is less than the radial height of each primary pleat and different from the radial height of at least one other secondary pleat. A filter element according to the present disclosure provides greater filter area, an increased overall filter density, and access to more radial flow paths at the outer diameter of the filter element.

Claims

1. A cylindrical filter element comprising:

a plurality of longitudinally extending pleats including outwardly radiating primary pleats and inwardly radiating secondary pleats, at least one secondary pleat positioned between two adjacent primary pleats, each primary pleat having a radial height, each secondary pleat having a radial height that is less than the radial height of each primary pleat and different from the radial height of each other secondary pleat.

2. A filter element according to claim 1, wherein one secondary pleat is positioned between two adjacent pairs of primary pleats.

3. A filter element according to claim 1, wherein two secondary pleats are positioned between two adjacent pairs of primary pleats.

4. A filter element according to claim 1, wherein one secondary pleat is positioned between two adjacent primary pleats.

5. A filter element according to claim 1, wherein two secondary pleats are positioned between two adjacent primary pleats.

6. A filter element according to claim 1, wherein the maximum number of primary pleats in the filter element is about equal to:

$\frac{\mathrm{\pi <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>d_{\mathrm{inner}}}{t}$

where “

d_inner”

is equal to an inner diameter of the filter element, and “

t”

is equal to a thickness of the pleats.

7. A filter element according to claim 1, wherein the maximum number of secondary pleats in the filter element is about equal to:

$\frac{\left(d_{\mathrm{outer}}-d_{\mathrm{inner}}\right)<br><br>\mathrm{\pi <br><br>}}{t}$

where “

d_inner”

is equal to an inner diameter of the filter element, “

d_outer”

is equal to an outer diameter of the filter element, and “

t”

is equal to a thickness of the pleats.

8. A filter element according to claim 7, wherein the number of secondary pleats included in the filter element is less than the maximum number of secondary pleats.

9. A filter element according to claim 1, wherein the filter element has a maximum secondary pleat height associated therewith, and the filter element is constructed in such a manner so that each secondary pleat has a radial height that is less than or equal to the maximum secondary pleat height.

10. A filter element according to claim 1, wherein the filter element has a minimum secondary pleat height associated therewith, and the filter element is constructed in such a manner so that each secondary pleat has a radial height that is greater than or equal to the minimum secondary pleat height.

11. A filter element according to claim 1, wherein the filter element comprises a pleated composite including a filter medium and at least one of an upstream diffusion medium and a downstream diffusion medium.

12. A filter element according to claim 11 wherein the at least one diffusion medium comprises one of an extruded netting and a spunbond, non-woven polymer.

13. A filter element according to claim 11, wherein the at least one diffusion medium comprises a thermoplastic selected from the group consisting of polypropylene, nylon, polyester and fluoropolymer.

14. A filter element according to claim 11 including an upstream diffusion medium and a downstream diffusion medium, wherein the upstream diffusion medium comprises extruded polypropylene netting, and the downstream diffusion medium comprises spunbond, non-woven polypropylene.

15. A filter element according to claim 11 wherein the filter medium comprises a thermoplastic selected from the group consisting of polypropylene, nylon, polyester and fluoropolymer.

16. A filter element according to claim 11 wherein the filter medium comprises non woven micro fibers.

17. A filter element according to claim 11, wherein the pleated composite is heat-set.

18. A filter element according to claim 1, wherein the filter element comprises a pleated composite including:

a) a filter medium of non woven thermoplastic polypropylene micro fibers;

b) a downstream diffusion medium of spunbond, non-woven polypropylene; and

c) an upstream diffusion layer of extruded polypropylene mesh.

19. A cartridge assembly including the filter of claim 1 and further comprising a cylindrical core coaxially positioned within the cylindrical filter element, and a cylindrical cage coaxially positioned about the cylindrical filter element.

20. A cylindrical filter element comprising:

a plurality of longitudinally extending pleats including outwardly radiating primary pleats and inwardly radiating secondary pleats, at least one secondary pleat positioned between two adjacent primary pleats, each primary pleat having a radial height, each secondary pleat having a radial height that is less than the radial height of each primary pleat and different from the radial height of at least one other secondary pleat, wherein the maximum number of secondary pleats in the filter element is about equal to;

$\frac{\left(d_{\mathrm{outer}}-d_{\mathrm{inner}}\right)<br><br>\mathrm{\pi <br><br>}}{t}$

where “

d_inner”

is equal to an inner diameter of the filter element, “

d_outer”

is equal to an outer diameter of the filter element, and “

t”

is equal to a thickness of the pleats.

21. A filter element according to claim 20, wherein the maximum number of primary pleats in the filter element is about equal to:

$\frac{\mathrm{\pi <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>d_{\mathrm{inner}}}{t}.$

22. A filter element according to claim 21, wherein the filter element includes less than the maximum number of primary pleats.

23. A filter element according to claim 21, wherein the filter element includes less than the maximum number of secondary pleats.

24. A filter element according to claim 21, wherein each secondary pleat has a different radial height.

25. A filter element according to claim 21, wherein one secondary pleat is positioned between two adjacent pairs of primary pleats.

26. A filter element according to claim 21, wherein two secondary pleats are positioned between two adjacent pairs of primary pleats.

27. A filter element according to claim 21, wherein one secondary pleat is positioned between two adjacent primary pleats.

28. A filter element according to claim 21, wherein two secondary pleats are positioned between two adjacent primary pleats.