Multicomponent depth odor control filter and method of manufacture

• US 5,951,744 A
• Filed: 11/04/1997
• Issued: 09/14/1999
• Est. Priority Date: 12/23/1994
• Status: Expired due to Term

• Current Assignee: FRAM Group IP, LLC
• Original Assignee: Alliedsignal Inc. (Honeywell International Inc.)
• Inventors: Xue, Lixin, Bause, Daniel E., Unger, Peter D., Rohrbach, Ronald P., Jones, Gordon W., Dondero, Russell A.
• Primary Examiner(s): Chiesa, Richard L.
• Application Number:
  US08/963,920
• Time in Patent Office: 679 Days
• Field of Search: 96/290, 96/294, 96/296, 96/181, 96/143, 96/144, 96/154, 96/FOR 123, 96/FOR 124, 428/397, 428/398, 428/362, 428/372, 264/241, 264/259, 264/273, 264/257, 264/271.1, 264/279, 264/279.1, 55/302, 55/303, 55/524, 55/521, 55/DIG. 5, 55/527, 55/528, 261/80, 261/94, 261/99, 261/104, 261/107, 261/DIG. 17, 261/DIG. 65, 95/210-212, 95/159, 95/171, 95/170
• US Class Current: 96/154
• CPC Class Codes: B01J 20/0244 Compounds of Zn
• CPC Class Codes: B01J 20/041 Oxides or hydroxides
• CPC Class Codes: B01J 20/165 Natural alumino-silicates, e.g. zeolites
• CPC Class Codes: B01J 20/20 comprising free carbon; comprising carbon obtained by carbonising processes
• CPC Class Codes: B01J 20/28004 Sorbent size or size distribution, e.g. particle size
• CPC Class Codes: B01J 20/28021 Hollow particles, e.g. hollow spheres, microspheres or cenospheres
• CPC Class Codes: B01J 20/28023 Fibres or filaments fibres or filaments in the form of membranes B01J20/28038; B01J20/28007 takes precedence
• CPC Class Codes: B01J 20/28026 Particles within, immobilised, dispersed, entrapped in or on a matrix, e.g. a resin
• CPC Class Codes: B01J 20/28028 Particles immobilised within fibres or filaments
• CPC Class Codes: B01J 20/28033 Membrane, sheet, cloth, pad, lamellar or mat
• CPC Class Codes: B01J 20/28038 Membranes or mats made from fibers or filaments
• CPC Class Codes: B01J 20/321 consisting of a polymer obtained by reactions involving only carbon to carbon unsaturated bonds
• CPC Class Codes: B01J 20/3212 consisting of a polymer obtained by reactions otherwise than involving only carbon to carbon unsaturated bonds
• CPC Class Codes: B01J 20/3236 containing metal, other than zeolites, e.g. oxides, hydroxides, sulphides or salts
• CPC Class Codes: B01J 20/324 containing free carbon, e.g. activated carbon
• CPC Class Codes: B01J 20/3287 Layers in the form of a liquid
• CPC Class Codes: B01J 20/3289 Coatings involving more than one layer of same or different nature
• CPC Class Codes: B01J 2220/485 Plants or land vegetals, e.g. cereals, wheat, corn, rice, sphagnum, peat moss
• CPC Class Codes: B01J 2220/56 Use in the form of a bed
• CPC Class Codes: C22B 3/22 by physical processes, e.g. by filtration, by magnetic means , or by thermal decomposition treatment or purification of solutions by liquid-liquid extraction C22B3/26
• CPC Class Codes: Y02P 10/20 : Recycling
• CPC Class Codes: Y10S 264/48 : Processes of making filters
• CPC Class Codes: Y10S 55/05 : Methods of making filter
• CPC Class Codes: Y10T 428/2927 : including structurally defined particulate matter
• CPC Class Codes: Y10T 428/2975 : Tubular or cellular

Abstract

A unique filtration device (10) which continuously removes gas phase contaminants from an air stream through the use of partially hollow wicking fibers (20) impregnated with a fine solid carbon powder (18) or zeolites and formed into a fiber filter (12) with a selected chemisorptive liquid applied to one side of the fiber filter (12) and large carbon particles (19) applied to the other side of the fiber filter (12). The air stream to be cleaned is directed through filter element (12) which can capture the gas phase contaminants. The wicking fibers (20) include internal longitudinal cavities (22) filled with the fine carbon powder (18) and each having a relatively small longitudinal extending opening (24). The wicking fibers (20), to a shallow depth on one side of filter (12), are filled with the selected contaminant removing chemisorptive liquid through capillary action by which the individual wicking fibers (20) rapidly draw the selected chemisorptive liquid, with which they come into contact, through the internal cavities (22). The chemisorptive liquid and fine carbon powder (18) or zeolite powder remain within the wicking fiber cavities (22) and generally do not enter the space between the wicking fibers yet through the longitudinal openings (24) the fine carbon particles (18) and the chemisorptive liquid are in full fluid communication with the air stream flowing past the fibers (20).

Claims

1. A filter using a fiber mat for removal of molecules from a fluid stream comprising:

a plurality of elongated fibers, each having a longitudinally extending internal cavity including an opening from the internal cavity to the outer fiber surface, disposed to form the fiber mat;

a fine powder, having an affinity for molecules to be removed from the fluid stream, made from particles which are smaller than the opening disposed and retained within the internal cavities of said plurality of elongated fibers;

a plurality of large carbon particles attached to one side of the fiber mat; and

,

a liquid chemisorptive agent, having an affinity for molecules to be removed from the fluid stream, disposed to a shallow depth on the other side of the fiber mat.

2. A filter as claimed in claim 1 wherein each elongated fiber is less than 250 microns in diameter and the majority of fine powder particles are less than 20 microns in size.

3. A filter as claimed in claim 1 wherein said fine powder comprises carbon or zeolites.

4. A filter as claimed in claim 1 wherein a plurality of internal cavities, each including an opening to the outer fiber surface, are formed in each fiber.

5. A filter as claimed in claim 1 wherein the diameter of said elongated fibers is less than 250 microns, the width of said elongated opening is less than one half the strand diameter and the average diameter of said plurality of solid particles is less than 10 microns.

6. A filter as claimed in claim 1 wherein said liquid chemisorptive agent comprises Group 1 or Group 2 hydroxide, carbonates, phosphates, borates, pyrophosphates, and Group 6 to 12 metal halides, acetates, phosphates, nitrates, or Group 1 permanganate.

7. A filter formed from a shaped fiber mat comprising:

a plurality of elongated fibers, forming the shaped fiber mat, each having a longitudinally extending internal cavity including an opening from the internal cavity to the outer fiber surface;

a fine powder made from particles which are smaller than the opening disposed within the internal cavities of said plurality of elongated fibers;

carbon particles which are much larger than the opening attached to one side of the shaped fiber mat; and

,

a liquid chemisorptive reagent disposed in a thin layer on the other side of the shaped fiber mat.

8. A filter as claimed in claim 7 wherein the fine powder particles are activated carbon or zeolites.

9. A filter as claimed in claim 7 wherein a plurality of internal cavities, each including an opening to the outer fiber surface, are formed in each fiber.

10. A filter as claimed in claim 7 wherein said liquid chemisorptive reagent comprises Group 6-12 metal acetates alkali combinations.

11. A filter as claimed in claim 10 wherein said liquid chemisorptive reagent comprises zinc acetate-potassium hydroxide.

12. A filter for removing odor molecules from an air stream comprising:

a plurality of elongated fibers, each having an elongated open channel extending into the interior of the fiber, disposed to form a fiber filter mat;

a fine powder, which has an affinity for selected types of odor molecules to be removed from the air stream, disposed and retained without an adhesive within the elongated open channels of said plurality of elongated fibers for adsorbing selected types of odor molecules as the air stream passes through the filter; and

,

a liquid chemisorptive agent, which has an affinity for selected types of odor molecules to be removed from the air stream, disposed to a shallow depth on one side of the fiber filter mat within the elongated open channels and having an exposed portion near the exteriors of the fibers for absorbing selected types of odor molecules as the air stream passes through the filter.

13. A filter as claimed in claim 12 comprising a plurality of carbon or zeolite particles, larger than the diameter of the fibers, attached to the other side of the fiber mat.

14. A filter as claimed in claim 12 wherein the fine powder particles are activated carbon or zeolites.

15. A filter as claimed in claim 12 wherein a plurality of internal cavities, each including an opening to the outer fiber surface, are formed in each fiber.

16. A device for continuously removing undesirable odor vapors from an air stream comprising:

a plurality of wicking fibers, disposed to form a fiber mat, with each wicking fiber including a longitudinally extending channel with a longitudinally extending opening;

a fine powder having an affinity for the undesirable odor vapors disposed within the longitudinally extending channels of said plurality of wicking fibers;

a liquid chemisorptive agent having an affinity for the undesirable odor vapors disposed to a shallow depth on one side of said fiber mat within the longitudinally extending channels of said plurality of wicking fibers;

means for directing the air stream across a part of said plurality of wicking fibers into contact with said fine powder and said liquid chemisorptive agent along said longitudinally extending openings whereby said fine powder and said liquid chemisorptive agent adsorb or absorb the undesirable odor vapors.

17. A device for continuously removing undesirable odor vapors as claimed in claim 16 comprising carbon particles, larger than said wicking fibers diameters, attached to the other side of said fiber mat.

18. A device for continuously removing undesirable odor vapors as claimed in claim 16 wherein a plurality of internal cavities, each including an opening to the outer fiber surface, are formed in each fiber.

19. A device for continuously removing undesirable odor vapors as claimed in claim 16 wherein said liquid chemisorptive agent comprises Group 1 metal permanganate in combination with either Group 1 metal carbonate or phosphate.

20. A filter for removing odor molecules comprising:

a plurality of elongated flexible fibers, each having an elongated open channel extending into the interior of the fiber, disposed to form a nonwoven fiber filter mat;

a plurality of small solid particles which have an affinity for odor molecules disposed and permanently retained by mechanical interaction within the channels for adsorbing some odor gas molecules as they pass through the filter; and

,

a plurality of larger carbon particles which are larger than the diameter of the fibers attached to one side of the nonwoven fiber filter mat.

21. A filter for removing odor molecules as claimed in claim 20 comprising a liquid chemisorptive agent which has an affinity for selected types of odor molecules to be removed disposed to a shallow depth on the other side of the fiber filter mat within the elongated open channels for absorbing selected types of odor molecules.

22. A method of manufacturing for a filter a fiber mat formed from strands impregnated with solid particles comprising the steps of:

a. forming a fiber mat from strands with each strand having an internal longitudinally extending cavity having a longitudinally extending opening, smaller than the cavity width, extending from the cavity to the fiber strand outser surface;

b. applying a plurality of solid particles to the fiber mat;

c. forcing many of the solid particles into the internal longitudinally extending cavities of the strands where they are securely retained without an adhesive; and

d. applying a liquid chemisorptive agent on one side of the fiber mat whereby the liquid chemisorptive agent is by capillary action drawn into at least some of the longitudinally extending cavities.

23. A method as claimed in claim 22 of manufacturing for a filter a fiber mat formed from strands impregnated with solid particles wherein the plurality of solid particles in step b are applied to one side of the fiber mat, and further comprising the additional step of:

e. attaching a plurality of carbon particles which are larger than the strands to the other side of the fiber mat.