Filtration device and method using absorption for the removal of gas phase contaminants

• US 6,004,381 A
• Filed: 10/23/1997
• Issued: 12/21/1999
• 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: Kheradi, Bijan, Sturgeon, Richard M., Unger, Peter D., Rohrbach, Ronald P., Jones, Gordon W.
• Primary Examiner(s): Chiesa, Richard L.
• Application Number:
  US08/958,719
• Time in Patent Office: 789 Days
• Field of Search: 261/104, 261/107, 261/DIG. 17, 261/DIG. 65, 95/170, 95/171, 95/159, 95/210-212, 96/130, 96/298, 96/361, 96/181, 96/99, 96/296, 55/528, 55/302, 55/303, 428/397, 428/398, 428/362, 428/372, 428/365
• US Class Current: 95/211
• CPC Class Codes: B01D 39/1623 of synthetic origin
• CPC Class Codes: B01D 47/027 by directing the gas to be cleaned essentially tangential to the liquid surface
• CPC Class Codes: B01D 47/028 by directing the gas through a wetted wire mesh or a perforated plate B01D47/14 takes precedence
• CPC Class Codes: B01D 50/60 Combinations of devices covered by groups B01D46/00 and B01D47/00
• CPC Class Codes: B01D 53/18 Absorbing units; Liquid distributors therefor B01D3/16, B01D3/26, B01D3/30 take precedence; packing elements B01J19/30, B01J19/32
• CPC Class Codes: B01J 20/28014 characterised by their form
• 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: B60H 2003/0691 Adsorption filters, e.g. activated carbon
• CPC Class Codes: B60H 3/06 Filtering B60H3/0078 takes precedence
• CPC Class Codes: B60H 3/0633 with provisions for regenerating or cleaning the filter element
• CPC Class Codes: B60H 3/0658 Filter elements specially adapted for their arrangement in vehicles B60H3/0608 takes precedence

Abstract

A filter device and technique are described which rely on absorption rather than adsorption for the removal of gas phase contaminants. A filter media is composed of wicking fibers which are impregnated with any of a variety of liquid phase absorbing systems made from the combination of a carrier liquid and soluble complexing/degrading agent or agents. The wicking fibers may be connected to an external reservoir which can be used to supply fresh absorbing fluid to the filter media giving them a potentially inexhaustible capacity. The filter media may be made from any of a variety of fibers which can rapidly transport a liquid phase by the nature of either their geometry or their chemical composition. Geometries may include multilobal cross-sectional configurations, porous hollow fibers, porous or striated fibers or tightly bundled microfibers, all of which exhibit the property of wicking fluid from an external source.

Claims

1. A method of removing undesirable gas phase material from an air stream comprising the steps of interposing a plurality of at least partially hollow wicking fibers in the air stream, with each wicking fiber having a least one slot extending along the wicking fiber and connecting the wicking fiber hollow internal region to an outer surface, and supplying a liquid including a component having an affinity for the undesirable gas phase material to the wicking fibers at a location outside the air stream whereby the wicking fibers can convey the liquid by capillary action into contact with the air stream along the slots while maintaining relatively open interstices between the fibers so that the air stream flow is substantially unimpeded by the liquid.

2. The method of claim 1 including the additional step of conveying the undersirable gas phase material in solution within the liquid from the air stream.

3. The method of claim 2 wherein the step of conveying comprises concentration factor induced molecular migration.

4. Apparatus for removing gas phase molecules from a fluid stream comprising:

a plurality of elongated fibers each having a longitudinally extending hollow internal cavity including an opening extending longitudinally along said fiber from the internal cavity to the outer fiber surface;

a liquid which can absorb the gas phase molecules disposed within the internal cavities of said plurality of elongated fibers;

a flow path for the fluid stream, containing the gas phase molecules to be removed, directed over a portion of said plurality of elongated fibers whereby the gas phase molecules to be removed are absorbed by said liquid; and

means for directing said fluid stream along said flow path.

5. Apparatus as claimed in claim 4 wherein the longitudinally extending internal cavity in each of said plurality of elongated fibers is sized so that said liquid is retained within the cavity by capillary forces.

6. Apparatus as claimed in claim 4 wherein the gas phase molecules to be removed which are absorbed by said liquid are moved within said liquid by a concentration factor-induced molecular migration.

7. Apparatus as claimed in claim 4 wherein the fluid stream is air.

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

9. A filter for removing selected types of gas phase molecules from a fluid 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; and

a liquid which has an affinity for the selected types of gas phase molecules disposed and retained within the channels and having an exposed portion, near the exterior of the fiber, for communicating with the fluid stream along the open channel and absorbing the selected types of gas phase molecules as the the fluid stream passes through the filter.

10. A filter as claimed in claim 9 wherein each fiber includes a plurality of elongated open channels within which the liquid which can absorb the selected types of gas phase molecules is disposed.

11. A filter as claimed in claim 9 wherein the fibers are disposed in generally a parallel alignment in the fiber filter mat.

12. A filter as claimed in claim 9 wherein the fibers are disposed randomly in the fiber filter mat.

13. An air filtration system for removing gas phase contaminants comprising:

a plurality of fibers each having at least one longitudinally extending open channel projecting into the interior of the fiber,

a liquid which can absorb the gas phase contaminants disposed within the open channels in said plurality of fibers, and

an air flow path containing the gas phase contaminants directed over a portion of said plurality of fibers whereby the exposed portion of said liquid disposed in the open channels is in liquid communication with the air flow path and absorbs the gas phase contaminants.

14. An air filtration system for removing gas phase contaminants as claimed in claim 13 comprising gas phase contaminant removal means for removing the absorbed gas phase contaminants from said liquid at a location which is outside of said air flow path.

15. A filtration device for removing vapor molecules which cause odors from an air stream comprising:

a housing;

an air flow path through said housing for the air stream;

a fibrous wicking material having a plurality of strands which are disposed in said housing to intercept the air flow path;

said plurality of strands each having a hollow internal region connected to an outer surface through at least one longitudinally extending opening;

a selected vapor absorbing liquid disposed in the hollow internal regions of said plurality of strands and communicating through said longitudinally extending openings in said plurality of strands with the air stream following the air flow path through said housing; and

,

means for directing said air stream into contact with said selected vapor absorbing liquid along said longitudinally extending openings whereby said selected vapor absorbing liquid absorbs odor causing vapors molecules through said longitudinally extending openings.

16. A method for continuously removing specific types of gas molecules from a gas stream comprising the steps of:

a. selecting a liquid which has an affinity for the specific types of gas molecules to be removed;

b. placing the selected liquid on a mat formed from a plurality of wicking fibers which have the ability to move the selected liquid along their surface yet retain the selected liquid within longitudinally extending channels having longitudinally extending openings against moving into the space between the individual wicking fibers;

c. directing the gas stream through a portion of the mat into contact with the selected liquid along the longitudinally extending openings whereby the selected liquid absorbs the specific types of gas molecules.

17. A method for continuously removing specific types of gas molecules from a gas stream as claimed in claim 16 comprising the additional step of:

d. directing a second gas stream through a different portion of the mat so that the specific type of gas molecules, which have been absorbed by and disbursed through out the selected liquid, are stripped and carried away.