Filter medium and structure

• US 8,268,033 B2
• Filed: 05/18/2011
• Issued: 09/18/2012
• Est. Priority Date: 11/05/2004
• Status: Active Grant

• Current Assignee: Donaldson Company Incorporated
• Original Assignee: Donaldson Company Incorporated
• Inventors: Rogers, Robert M., Dema, Keh B.
• Primary Examiner(s): CLEMENTE, ROBERT ARTHUR
• Application Number:
  US13/110,148
• Publication Number:
  US 20110215046A1
• Time in Patent Office: 489 Days
• Field of Search: 555/27, 555/28, 210/505, 210/508, 210/509
• US Class Current: 55/527
• CPC Class Codes: B01D 2239/0216 Bicomponent or multicomponent fibres
• 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 2239/0668 The layers being joined by heat or melt-bonding
• CPC Class Codes: B01D 2275/10 Multiple layers
• CPC Class Codes: B01D 2279/60 for the intake of internal combustion engines or turbines intake systems for vehicles comprising filters F02M35/024
• CPC Class Codes: B01D 39/1615 of natural origin
• CPC Class Codes: B01D 39/163 sintered or bonded
• 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 39/2017 the material being filamentary or fibrous
• CPC Class Codes: B01D 39/2024 otherwise bonded, e.g. by resins
• CPC Class Codes: B01D 39/2037 otherwise bonded
• 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 46/2411 Filter cartridges
• CPC Class Codes: B01D 46/521 using folded, pleated material
• CPC Class Codes: B01D 46/71 with pressurised gas, e.g. pulsed air
• CPC Class Codes: Y10T 442/616 Blend of synthetic polymeric and inorganic microfibers
• CPC Class Codes: Y10T 442/622 Microfiber is a composite fiber
• CPC Class Codes: Y10T 442/623 Microfiber is glass
• CPC Class Codes: Y10T 442/637 Including strand or fiber material which is a monofilament composed of two or more polymeric materials in physically distinct relationship [e.g., sheath-core, side-by-side, islands-in-sea, fibrils-in-matrix, etc.] or composed of physical blend of chemically different polymeric materials or a physical blend of a polymeric material and a filler material

Abstract

Thermoplastic bicomponent binder fiber can be combined with other media, fibers and other filtration components to form a thermally bonded filtration media. The filtration media can be used in filter units, such as breather caps. Such filter units can be placed in the stream of a mobile fluid and can remove a particulate and/or fluid mist load from the mobile stream. The unique combination of media fiber, bicomponent binder fiber and other filtration additives and components provide a filtration media having unique properties in filtration applications.

Claims

1. A filtration medium comprising a depth loading medium having a thickness of 0.1 to 2 mm comprising a thermally bonded nonwoven structure comprising bicomponent fibers blended with glass fibers, wherein the bicomponent fibers have a concentric sheath-core structure consisting essentially of polyester or polyamide, the filtration medium having a solidity of about 2 to 25%, a basis weight of about 10 to 300 g/m², and a compressibility of 25% or less when pressure is varied from 0.125 lb/in² to 0.625 lb/in².

2. The filtration medium of claim 1, wherein the bicomponent fibers consist essentially of polyester.

3. The filtration medium of claim 2 wherein the polyester consists essentially of polyethylene terephthalate.

4. The filtration medium of claim 2, wherein the bicomponent fibers are 2.2 DTEX×

5 mm or 4.4 DTEX×

5 mm.

5. The filtration medium of claim 2, further comprising secondary monocomponent media fibers which cooperate with the glass fibers and the bicomponent fibers to form the filter medium.

6. The filtration medium of claim 5, wherein the secondary fibers comprise polyester.

7. The filtration medium of claim 1 wherein the polyamide consists essentially of a nylon.

8. The filtration medium of claim 1 wherein the medium has solidity of less than 10%.

9. The filtration medium of claim 1 wherein the medium has basis weight of about 20 to 200 g/m².

10. The filtration medium of claim 1 wherein the medium has permeability of about 5 to 500 ft/min.

11. The filtration medium of claim 1 wherein the medium has permeability of about 5 to 200 ft/min.

12. The filtration medium of claim 1 wherein the medium has a thickness of 0.2 to 2 mm and a compressibility of about 10 to 20% when pressure is varied from 0.125 lb/in² to 0.625 lb/in².

13. The filtration medium of claim 1, wherein the thermally bonded nonwoven structure is a sheet.

14. A filter structure comprising 2 to 100 of the sheets of claim 13.

15. The filtration medium of claim 1, wherein the medium comprises 4 to 100 layers.

16. The filtration medium of claim 1, further comprising a hinder resin provided as an aqueous dispersion.

17. The filtration medium of claim 1 wherein the medium is substantially free of residue from an aqueous binder resin.

18. The filtration medium of claim 1, wherein the medium comprises:

(a) about 20 to 80 wt % of the bicomponent fibers, the bicomponent fibers having a fiber diameter of about 5 to 50 micrometers and a fiber length of about 0.1 to 15 cm; and

(b) about 20 to 80 wt % of the glass fibers, the glass fibers having a fiber diameter of about 0.1 to 30 micrometers and an aspect ratio of about 10 to 10,000;

wherein the medium has a thickness of about 0.2 to 50 mm, a solidity of less than 10%, a pore size of about 0.5 to 100 micrometers, and a permeability of about 5 to 500 ft-min<sup>−

1</sup>.

19. The filtration medium of claim 1 comprising

about 50% to 70% by weight of the bicomponent fibers, wherein the bicomponent fibers have a diameter of between 10 and 20 micrometers;

and

about 50% or less by weight of the glass fibers, wherein the glass fibers have a diameter of about 0.2 micrometers to 2.6 micrometers.

20. The filtration medium of claim 1 wherein the bicomponent fiber has a fiber diameter of about 14 micrometers.

21. The filtration medium of claim 19 comprising about 50% by weight of the bicomponent fiber.

22. The filtration medium of claim 19 wherein the glass fibers are present as a blend of glass fibers comprising a first glass fiber having a first diameter and a second glass fiber having a second diameter.

23. The filtration medium of claim 22 wherein the first diameter is about 0.5 to 5 micrometers and the second diameter is about 0.1 to 1 micrometers.