AIR PURIFYING FILTER SYSTEMS FOR BUILDING AIR SUPPLY AND RESPIRATORS USEFUL AGAINST NBC ATTACKS

• US 20040255785A1
• Filed: 02/21/2003
• Published: 12/23/2004
• Est. Priority Date: 02/22/2002
• Status: Active Grant

• Current Assignee: KX Technologies, LLC (Berkshire Hathaway Incorporated)
• Original Assignee: Koslow Tech Corp
• Inventors: Koslow, Evan E.
• Granted Patent: US 6,840,986 B1
• Time in Patent Office: Days
• US Class Current: 96/154
• CPC Class Codes: A62B 23/02 for respirators
• CPC Class Codes: A62B 23/04 for gasproof shelters
• CPC Class Codes: B01D 2253/10 Inorganic adsorbents
• CPC Class Codes: B01D 2253/102 Carbon
• CPC Class Codes: B01D 2253/104 Alumina
• CPC Class Codes: B01D 2253/11 Clays
• CPC Class Codes: B01D 2253/1124 Metal oxides
• CPC Class Codes: B01D 2253/20 Organic adsorbents
• CPC Class Codes: B01D 2253/206 Ion exchange resins
• CPC Class Codes: B01D 2253/25 Coated, impregnated or composite adsorbents
• CPC Class Codes: B01D 2253/304 Linear dimensions, e.g. particle shape, diameter
• CPC Class Codes: B01D 2253/306 Surface area, e.g. BET-specific surface
• CPC Class Codes: B01D 2253/34 Specific shapes
• CPC Class Codes: B01D 2257/204 Inorganic halogen compounds
• CPC Class Codes: B01D 2257/93 Toxic compounds not provided for in groups B01D2257/00 - B01D2257/708
• CPC Class Codes: B01D 2258/0225 from chemical or biological warfare
• CPC Class Codes: B01D 2259/4148 Multiple layers positioned apart from each other
• CPC Class Codes: B01D 2259/4508 for cleaning air in buildings
• CPC Class Codes: B01D 2259/4583 for removing chemical, biological and nuclear warfare agents
• CPC Class Codes: B01D 2275/10 Multiple layers
• CPC Class Codes: B01D 39/202 : sintered or bonded by inorganic agents
• CPC Class Codes: B01D 46/0036 : by adsorption or absorption
• CPC Class Codes: B01D 46/0091 : Including arrangements for environmental or personal protection
• 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 46/64 : arranged concentrically or coaxially
• CPC Class Codes: B01D 53/02 : by adsorption, e.g. preparative gas chromatography solid sorbent compositions B01J20/00, preparation of inorganic compounds or elements C01
• CPC Class Codes: B01D 53/0431 : Beds with radial gas flow
• CPC Class Codes: F24F 13/28 : Arrangement or mounting of filters
• CPC Class Codes: F24F 2221/44 : Protection from terrorism or theft
• CPC Class Codes: F24F 8/158 : using active carbon
• CPC Class Codes: Y10S 55/33 : Gas mask canister
• CPC Class Codes: Y10S 55/35 : Respirators and register filters

Abstract

An air filter that can fit within existing building HVAC air supply systems suitable for withstanding NBC attacks, comprising a series of pleated composite layers. By using impregnated carbon particles of the proper size, nerve gases, and gases of lower molecular weight, such as cyanogen chloride, are effectively controlled, even under tests simulating large-scale attacks. A particulate filter such as, for example, a HEPA filter, may be included to control biological particles or toxic aerosol droplets. The complete filter operates at such a low differential pressure, that existing building mechanicals do not have to be upgraded or replaced. Also disclosed is a filter for use with a respirator.

Claims

1. A filter system comprising:

one or more pleated layers of a high surface area composite operating in series, each layer having an air permeability greater than about 9 m/min at about 1.27 cm water column, and comprising adsorbent or chemically reactive particles immobilized into a flexible form and containing greater than about 300 g/m² of said particles, and wherein a pressure drop of a plurality of layers is less than about 5 cm water column at a rated flow for a given air purification application.

2. The filter system of claim 1 wherein the adsorbent or chemically reactive particles of the composite comprise activated carbon.

3. The filter system of claim 2 wherein the activated carbon is packed to a density of about 85% to about 115% of a bulk density of the activated carbon.

4. The filter system of claim 2 wherein the activated carbon has an average particle size of about 20×

50 mesh.

5. The filter system of claim 1 wherein the high surface area composite contains about 500 to greater than about 2000 g/m² of activated carbon.

6. The filter system of claim 1 wherein the high surface area composite further comprises a first air permeable substrate, a second air permeable substrate, and binder, wherein the adsorbent or chemically reactive particles and binder are admixed and disposed between the first air permeable substrate and the second air permeable substrate such that a portion of the adsorbent or chemically reactive particles are bound to the second air permeable substrate by a portion of the binder.

7. The filter system of claim 1 wherein the one or more pleated layers of the high surface area composite generates a pressure drop of no more than about 0.635 cm water column at a flow rate of about 57.912 m/min.

8. The filter system of claim 1 wherein the one or more pleated layers of the high surface area composite further comprises particles selected from the group consisting of activated alumina, zeolites, diatomaceous earth, silicates, aluminosilicates, titanates, bone char, calcium hydroxyapatite, manganese oxides, iron oxides, magnesia, perlite, talc, polymeric particulates, clay, iodated resins, ion exchange resins, ceramics, and combinations thereof.

9. The filter system of claim 1 wherein said one or more pleated layers of the high surface area composite are configured as a radial flow air filter material.

10. The filter system of claim 1 in combination with a collective protection system.

11. The filter system of claim 1 retrofitted into an existing building ventilation system.

12. The filter system of claim 1 further including a high efficiency particulate air filter medium.

13. A filter system comprising:

a plurality of composite layers operating in series, each of said composite layers comprising;

a first air permeable substrate;

a second air permeable substrate; and

activated carbon particles loaded at a high density at a rate of about 600 to 2000 g/m² between the first air permeable substrate and the second air permeable substrate and further including a binder wherein at least a portion of the binder binds at least a portion of the activated carbon particles to one another and at least a portion of the activated carbon particles to one or both of the first air permeable substrate and the second air permeable substrate,

wherein a pressure drop of the plurality of composite layers is less than about 5 cm water column at a rated flow for a given air purification application.

14. The filter system of claim 13 wherein the activated carbon particles have an average particle size of about 20×

50 mesh.

15. The filter system of claim 13 wherein the activated carbon particles comprise an impregnated carbon.

16. The filter system of claim 13 wherein each composite layer has a thickness of about 1.4 mm.

17. The filter system of claim 13 wherein each layer of composite layer is pleated with about three pleats per inch.

18. The filter system of claim 17 in combination with a collective protection system.

19. The filter system of claim 13 wherein said plurality of composite layers are spiral wound.

20. The filter system of claim 19 in combination with a collective protection system.

21. The filter system of claim 13 wherein said plurality of composite layers are stacked.

22. The filter system of claim 21 in combination with a collective protection system.

23. The filter system of claim 13 retrofitted into an existing building ventilation system.

24. The filter system of claim 13 further including a high efficiency particulate air filter medium.

25. A filter system comprising:

a plurality of flexible composite layers operating in series, each layer comprising;

a first air permeable substrate; and

activated carbon particles having a particle size of about 20×

50 mesh and binder disposed on the first air permeable substrate at a load rate of about 2000 g/m², a portion of the binder binding at least a portion of the activated carbon particles to one another and at least a portion of the activated carbon particles to the first air permeable substrate;

wherein the activated carbon particles are closely packed to a high density and compacted to a critical range of compaction wherein axial dispersion is reduced and permeability is high; and

a frame for encapsulating a periphery of each layer of said plurality of flexible composite layers, said frame being generally oval in shape and having a first radius of curvature in a first direction, and a second radius of curvature in a second direction.

26. The filter system of claim 25 wherein the second direction is perpendicular to the first direction, and the first radius of curvature and the second radius of curvature are selected so that said filter system generally follows a contour of a human adult cheek.

27. The filter of claim 25 in combination with a respirator, said respirator having a compartment for receiving said filter.