AIR FILTER MEDIA WITH POST-PLEAT-DEPOSITED SORBENT PARTICLES

• US 20200129907A1
• Filed: 04/18/2017
• Published: 04/30/2020
• Est. Priority Date: 04/18/2017
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Fox, Andrew R., Jasuja, Himanshu, Belkin, Mikhail A., Gerhardt, Bryan L., Gregerson, Glen O., Hoffdahl, Gerry A., Lise, Jonathan M., Wu, Tien T.
• Granted Patent: US 11,305,224 B2
• Time in Patent Office: Days
• CPC Class Codes: B01D 2265/04 Permanent measures for connecting different parts of the filter, e.g. welding, glueing or moulding
• CPC Class Codes: B01D 2279/50 for air conditioning
• CPC Class Codes: B01D 46/0001 Making filtering elements
• CPC Class Codes: B01D 46/0036 by adsorption or absorption
• 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 46/521 using folded, pleated material
• CPC Class Codes: B01D 46/522 with specific folds, e.g. having different lengths
• CPC Class Codes: B01D 46/523 with means for maintaining spacing between the pleats or folds

Abstract

An air filter media (10) including a pleated fibrous filtration web (8) with a first major side (2) that includes at least one sorbent-loaded area (26) in which sorbent particles (14) are present on a first major surface (25) of the pleated fibrous filtration web (8), at least some of the sorbent particles (14) being post-pleat-deposited sorbent particles.

Claims

1. An air filter media comprising:

a pleated fibrous filtration web with a first major side that includes at least one sorbent-loaded area in which sorbent particles are present on a first major surface of the pleated fibrous filtration web at a loading of at least about 20 grams per square meter,

wherein at least some of the sorbent particles are post-pleat-deposited sorbent particles.

2. The air filter media of claim 1 wherein the air filter media exhibits one or more structural characteristics that indicate that at least some of the sorbent particles were deposited on the first major surface of the fibrous filtration web to form the at least one sorbent-loaded area, subsequent to the fibrous filtration web being folded into a pleated configuration.

3. The air filter media of claim 2 wherein the one or more structural characteristics includes the condition that the at least one sorbent-loaded area comprises at least some first-side pleat valley floors that each exhibit a local loading of sorbent particles that is below 50 percent of a local loading of sorbent particles on a pleat wall that flanks the pleat valley floor.

4. The air filter media of claim 1 wherein the pleated fibrous filtration web is a scored pleated fibrous filtration web that exhibits at least some identifiable score lines that coincide with pleat tips and pleat valleys of the first major side of the pleated fibrous filtration web,

and wherein the air filter media exhibits one or more structural characteristics that indicate that at least some of the sorbent particles were deposited on the first major surface of the web to form the at least one sorbent-loaded area, subsequent to the fibrous filtration web being scored.

5. The air filter media of claim 1 wherein a plurality of bridging filaments are disposed on the first major side of the pleated fibrous filtration web, the bridging filaments extending in a direction that is at least generally perpendicular to a pleat direction of the pleated fibrous filtration web and at least some of the bridging filaments being bonded to at least some pleat tips of the first major side of the pleated fibrous filtration web;

and wherein the air filter media exhibits one or more structural characteristics that indicate that at least some of the sorbent particles were deposited on the first major surface of the pleated fibrous filtration web to form the at least one sorbent-loaded area, subsequent to the bridging filaments being disposed on the first major side of the pleated fibrous filtration web and being bonded to at least some pleat tips of the first major side of the pleated fibrous filtration web.

6. The air filter media of claim 1 wherein in the at least one sorbent-loaded area of the first major side of the pleated fibrous filtration web, a discontinuous adhesive layer is present on the first major surface of the pleated fibrous filtration web so that the sorbent particles are adhesively bonded to the first major surface of the pleated fibrous filtration web.

7. The air filter media of claim 6 wherein the air filter media exhibits one or more structural characteristics that indicate that at least some adhesive material was deposited on the first major surface of the pleated fibrous filtration web to form the discontinuous adhesive layer, subsequent to the fibrous filtration web being folded into a pleated configuration.

8. The air filter media of claim 7 wherein the air filter media exhibits one or more structural characteristics that indicate that the following process steps were carried out, in order:

scoring the fibrous filtration web;

folding the scored fibrous filtration web into a pleated configuration;

depositing adhesive material on the first major surface of the pleated fibrous filtration web to form a discontinuous adhesive layer;

disposing a plurality of bridging filaments on the first major side of the pleated fibrous filtration web and bonding the bridging filaments to at least some pleat tips of the first major side of the pleated fibrous filtration web; and

,

depositing sorbent particles on at least a portion of the first major surface of the first major side of the pleated fibrous web to provide at least one sorbent-loaded area comprising post-pleat-deposited sorbent particles.

9. The air filter media of claim 1 wherein the pleated fibrous filtration web exhibits a pleat spacing of less than about 10 mm, a pleat height of at least about 10 mm, and a pleat fold radius of curvature of less than about 2 mm.

10. The air filter media of claim 1 wherein in the at least one sorbent-loaded area of the first major side of the pleated fibrous filtration web, the sorbent particles are present on the first major surface of the pleated fibrous filtration web as a layer that exhibits an average thickness that is at least about 50% of an average thickness of the pleated fibrous filtration web.

11. An air filter comprising the air filter media of claim 1 with a perimeter frame mounted to a perimeter of the air filter media, so that the air filter is a framed air filter.

12. A method of forming an air filter media, the method comprising:

depositing sorbent particles on at least a portion of a first major surface of a pleated fibrous filtration web to form at least one sorbent-loaded area of the pleated fibrous filtration web.

13. The method of claim 12 wherein the method includes a step of scoring a fibrous filtration web and folding the fibrous filtration web to form the pleated fibrous filtration web, prior to depositing the sorbent particles on the first major surface of the pleated fibrous filtration web to form the at least one sorbent-loaded area.

14. The method of claim 12, wherein the first major surface of the pleated fibrous filtration web comprises a discontinuous layer of adhesive, and wherein the method includes a step of adhesively bonding the deposited sorbent particles to the first major surface of the pleated fibrous filtration web to form the at least one sorbent-loaded area.

15. The method of claim 14, wherein the method includes a step of folding a fibrous filtration web to form the pleated fibrous filtration web, followed by a step of depositing adhesive on the first major surface of the pleated fibrous filtration web to form the discontinuous layer of adhesive.

16. The method of claim 12, wherein the method includes a step of disposing a plurality of bridging filaments on a first major side of the pleated fibrous filtration web and bonding at least some of the bridging filaments to at least some pleat tips of the first major side of the pleated fibrous filtration web, which step is followed by the step of depositing sorbent particles on the first major surface of a pleated fibrous filtration web to form the least one sorbent-loaded area of the pleated fibrous filtration web.

17. The method of claim 16 wherein at least some of the sorbent particles pass through spaces between bridging filaments of the plurality of bridging filaments in the process of being deposited on the first major surface of the pleated fibrous filtration web.

18. The method of claim 16 wherein the method includes a step of folding a fibrous filtration web to form the pleated fibrous filtration web, followed by a step of depositing adhesive on the first major surface of the pleated fibrous filtration web to form the discontinuous layer of adhesive, with both steps preceding the step of disposing the plurality of bridging filaments on the first major side of the pleated fibrous filtration web and bonding at least some of the bridging filaments to at least some pleat tips of the first major side of the pleated fibrous filtration web.

19. The method of claim 18 wherein the method includes a step of scoring the fibrous filtration web prior to folding the fibrous filtration web to form the pleated fibrous filtration web.

20. The method of claim 12 wherein the method includes a step of disposing a plurality of bridging filaments on a second major side of the pleated fibrous filtration web and bonding at least some of the bridging filaments to at least some pleat tips of the second major side of the pleated fibrous filtration web, and a step of disposing a plurality of bridging filaments on a first major side of the pleated fibrous filtration web and bonding at least some of the bridging filaments to at least some pleat tips of the first major side of the pleated fibrous filtration web, with both of these steps preceding the step of depositing sorbent particles on the first major surface of a pleated fibrous filtration web to form the least one sorbent-loaded area of the pleated fibrous filtration web.

21. The method of claim 20 wherein the method includes a step of folding a fibrous filtration web to form the pleated fibrous filtration web, holding the pleated fibrous filtration web in its pleated formation by a holding fixture of a pleating apparatus, and disposing the plurality of bridging filaments on the second major side of the pleated fibrous filtration web and bonding at least some of the bridging filaments to at least some pleat tips of the second major side of the pleated fibrous filtration web to stabilize the pleated configuration of the pleated fibrous filtration web, after which the pleated fibrous filtration web is removed from the holding fixture of the pleating apparatus.

22. The method of claim 12, the method comprising the steps of, in order:

scoring a fibrous filtration web to provide score lines;

folding the scored fibrous filtration web along at least some of the score lines to form the pleated fibrous filtration web;

depositing adhesive material on the first major surface of a first major side of the pleated fibrous filtration web to form a discontinuous adhesive layer;

disposing a plurality of bridging filaments on the first major side of the pleated fibrous filtration web and bonding the bridging filaments to at least some pleat tips of the first major side of the pleated fibrous filtration web; and

,

depositing sorbent particles on at least a portion of the first major surface of the first major side of the pleated fibrous web and adhesively bonding the sorbent particles to the first major surface of the first major side of the pleated fibrous web, to provide the at least one sorbent-loaded area comprising post-pleat-deposited sorbent particles.

23. The method of claim 12 wherein the sorbent particles are deposited on at least a portion of a first major surface of a pleated fibrous filtration web to form at least one sorbent-loaded area of the pleated fibrous filtration web, by electrostatic deposition.