WO2004032580B1 - Emi-absorbing air filter - Google Patents
Emi-absorbing air filterInfo
- Publication number
- WO2004032580B1 WO2004032580B1 PCT/US2003/031119 US0331119W WO2004032580B1 WO 2004032580 B1 WO2004032580 B1 WO 2004032580B1 US 0331119 W US0331119 W US 0331119W WO 2004032580 B1 WO2004032580 B1 WO 2004032580B1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- porous substrate
- air filter
- electrically
- solution
- air
- Prior art date
Links
Classifications
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K9/00—Screening of apparatus or components against electric or magnetic fields
- H05K9/0007—Casings
- H05K9/0041—Ventilation panels having provisions for screening
Landscapes
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Shielding Devices Or Components To Electric Or Magnetic Fields (AREA)
- Filtering Materials (AREA)
Abstract
Electromagnetic-energy absorbing materials are used to treat air filters (300), such as those used in association with electronic equipment thereby suppressing the transmission of electromagnetic interference (EMI) therethrough. Disclosed are processes and materials for applying EMI-absorbing materials to air filters thereby improving EMI-shielding effectiveness in an economically efficient manner. In one embodiment, an absorptive solution (110) is prepared using an absorptive material and a binding agent. A heavy coating of absorbing solution is applied (120) to an air filter substrate (100), for example by dipping or spraying. Excess absorbing material is subsequently removed (130) and the absorbing material cured (140), such that the passage of air through the filter remains substantially unimpeded. The resulting absorptive air filter is then optionally treated (160) with a flame retardant to meet a predetermined safety standard.
Claims
1. An air filter having electromagnetic-energy absorptive characteristics, the filter comprising: a porous substrate; and an electrically absorptive material distributed substantially uniformly through the porous substrate, said electrically absorptive material being an electrical absorber in particulate form suspended in a binding agent.
2. cancelled
3. The air filter of claim I, wherein the electrical absorber is selected from the group consisting of carbon, carbon particles, carbon fibers, alumina, sapphire, silica, titanium dioxide, ferrite, iron, iron silicide, graphite, and composites of iron, nickel and copper.
4. The air filter of claim 15 wherein the binding agent is selected from the group consisting of an elastomer, a rubber and an epoχy.
5. The air filter of claim 1, wherein the electrically absorptive material further comprises a highly conductive material.
25
6. The air filter of claim 5, wherein the highly conductive material is selected from the group consisting of copper and aluminum.
7. The air filter of claim 1 , further comprising a fire-retardant layer.
8. The air filter of claim 7, wherein the fiτe-re.ardant layer comprises a fire rctardant selected from the group consisting of phosphates and antimony trioxide.
9. The air filter of claim 7, wherein the fire-retardant-treated porous substrate passes a self-extinguishing vertical burn requirement in accordance with Underwriters Laboratories Standard 94.
10. The air filter of claim 1, wherein the porous substrate comprises an open-cell reticulated polyurethane foam.
11. The air filter of claim 10, wherein the foam comprises at least about 10 pores per linear inch.
12. The air filter of claim 1, wherein the porous substrate comprises a fiberglass mat
13. The air filter of claim 1, wherein the porous substrate comprises a non-woven polyester web.
14. The air filter of claim 1 , further comprising an electrically conductive layer.
15. The air filter of claim 14, wherein said electrically conductive layer is an electrical conductor having an array of apertures through which air can flow.
16. The air filter of claim 14, wherein said electrically conductive layer is a conductive coating applied thereto.
17. The air filter of claim 14, wherein the electrically conductive layer comprises a honeycomb.
18. The air filter of claim 1, further comprising a frame fixedly attached to the porous substrate, wherein the frame provides physical support for the porous substrate.
19. The air filter of claim 1, wherein the porous substrate comprises a sheet having a thickness less than about 0.5 inches.
20. The air filter of claim 1 , wherein the porous substrate provides at least 20 dB of attenuation to electromagnetic energy substantially occurring at frequencies at least between about 4 GHz and IS GHz.
21. A method for producing an air filter having electroraagnetic-energy-absorptive
27 characteristics comprising the $teps of: providing a porous substrate having a first side and a second side; providing an electrically absorptive solution, said electrically absorptive solution being an electrical absorber in particulate form suspended in a liquid binding agent; applying said electrically absorptive solution to the porous substrate; distributing said electrically absorptive solution substantially uniformly through the porous substrate; and curing said electrically absorptive solution.
22. The method of claim 21 , wherein the applying step comprises the sub-steps of: immersing the porous substrate into the electrically absorptive solution, causing the electrically absorptive solution to penetrate the porous substrate; extracting the immersed porous substrate from the electrically absorptive solution; and removing excess electrically absorptive solution from the extracted porous substrate, thereby leaving a substantially uniform distribution of electrically absorptive solution through the porous substrate.
23. The method of claim 21, wherein the electrical absorber is selected from the group consisting of carbon, carbon particles, carbon fibers, alumina, sapphire, silica, titanium dioxide, feπite, iron, iron silicide, graphite, and composites of iron, nickel and copper.
28
24. The method of claim 21, wherein the bindmg agent is selected from the group consisting of an elastomer, a rubber and an epoxy.
25. The method of claim 21, further comprising the step of forcing air through the porous material during at least one of prior to curing and curing, thereby ensuring that pores remain substantially unblocked,
26. The method of claim 25, wherein the step of forcing air through the porous material comprises drawing a vacuum.
27. The method of claim 22, wherein the step of removing excess electrically absorptive solution comprises squeezing the extracted porous substrate.
28. The method of claim 21, wherein the step of applying an electrically absorptive solution is repeated,
29. The method of claim 21 , further comprising the step of applying a fire-retaτdant layer.
30. The method of claim 29, wherein the fite-retardant layer comprises a fire retardant selected from the group consisting of phosphates and antimony trioxide.
29
31. The method of claim 21, wherein the applying step comprises: spraying the electrically absorptive solution onto the first side of the porous substrate; and removing excess electrically absorptive solution from the sprayed, porous substrate, thereby leaving a substantially uniform distribution of electrically absorptive solution through the porous substrate.
32. The method of claim 31 , further comprising the step of spraying the electrically absorptive solution onto the second side of the porous substrate.
33. The method of claim 21, wherein the air-flow characteristics of the porous substrate are substantially equivalent before and after the application of the electrically absorptive solution.
34. The method of claim 21 , wherein a reduction in air-flow capacity of the porous substrate when compared before and after the application of the electrically absorptive solution is preferably less than 25%.
35. The method of claim 21 , wherein a reduction in air-flow capacity of the porous substrate when compared before and after the application of the electrically absorptive solution is more preferably less than 15%.
36. The method of claim 21, wherein a reduction in air-flow capacity of the porous
30 substrate when compared before and after the application of the electrically absorptive solution is even more preferably less than 10%.
31
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US10/530,110 US7338547B2 (en) | 2003-10-02 | 2003-10-02 | EMI-absorbing air filter |
| AU2003279736A AU2003279736A1 (en) | 2002-10-03 | 2003-10-02 | Emi-absorbing air filter |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US41592402P | 2002-10-03 | 2002-10-03 | |
| US60/415,924 | 2002-10-03 |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| WO2004032580A2 WO2004032580A2 (en) | 2004-04-15 |
| WO2004032580A3 WO2004032580A3 (en) | 2004-05-13 |
| WO2004032580B1 true WO2004032580B1 (en) | 2004-07-22 |
Family
ID=32069920
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/US2003/031119 WO2004032580A2 (en) | 2002-10-03 | 2003-10-02 | Emi-absorbing air filter |
Country Status (3)
| Country | Link |
|---|---|
| AU (1) | AU2003279736A1 (en) |
| TW (1) | TWI279248B (en) |
| WO (1) | WO2004032580A2 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI258771B (en) | 2001-12-04 | 2006-07-21 | Laird Technologies Inc | Methods and apparatus for EMI shielding |
| US8421045B2 (en) * | 2011-08-26 | 2013-04-16 | Bha Group, Inc. | Electromagnetic protection cloth |
| US9622338B2 (en) | 2013-01-25 | 2017-04-11 | Laird Technologies, Inc. | Frequency selective structures for EMI mitigation |
| WO2018194431A2 (en) * | 2017-04-21 | 2018-10-25 | 단국대학교 천안캠퍼스 산학협력단 | Membrane including metal substrate layer and cnt/chitosan nanohybrid coating layer, and electrostatic dust collection system including same |
| CN113045263B (en) * | 2021-03-18 | 2022-11-08 | 西南石油大学 | Hybrid fiber cement-based foam composite wave-absorbing material and preparation method thereof |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3546359A (en) * | 1969-06-18 | 1970-12-08 | Gichner Mobile Systems Inc | Rfi shielded vent |
| AU661855B2 (en) * | 1991-10-23 | 1995-08-10 | W.L. Gore & Associates, Inc. | Electromagnetic interference shielding filter |
| US5519168A (en) * | 1993-10-12 | 1996-05-21 | Owens; William M. | Electromagnetic interference shielding |
| US5431974A (en) * | 1993-12-16 | 1995-07-11 | Pierce; Patricia | Electromagnetic radiation shielding filter assembly |
| US6063152A (en) * | 1997-02-19 | 2000-05-16 | Marconi Communications Inc. | Tuned electromagnetic interference air filter |
| WO1999041963A1 (en) * | 1998-02-17 | 1999-08-19 | Parker-Hannifin Corporation | Emi shielded vent panel and method |
| US6171357B1 (en) * | 1999-01-04 | 2001-01-09 | Eci Telecom Ltd. | Air filter |
| WO2000062591A1 (en) * | 1999-04-13 | 2000-10-19 | Siemens Aktiengesellschaft | Device for cooling an electric module and a technical appliance |
| EP1121844B1 (en) * | 1999-08-17 | 2007-07-04 | Parker Hannifin Corporation | Emi shielding vent panel and manufacturing method thereof |
| US20030085050A1 (en) * | 2001-09-04 | 2003-05-08 | Shielding For Electronics, Inc. | EMI air filter |
-
2003
- 2003-10-02 TW TW92127300A patent/TWI279248B/en not_active IP Right Cessation
- 2003-10-02 WO PCT/US2003/031119 patent/WO2004032580A2/en not_active Application Discontinuation
- 2003-10-02 AU AU2003279736A patent/AU2003279736A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| TW200418560A (en) | 2004-10-01 |
| WO2004032580A2 (en) | 2004-04-15 |
| WO2004032580A3 (en) | 2004-05-13 |
| TWI279248B (en) | 2007-04-21 |
| AU2003279736A1 (en) | 2004-04-23 |
| AU2003279736A8 (en) | 2004-04-23 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US7338547B2 (en) | EMI-absorbing air filter | |
| DE60305388T2 (en) | Electromagnetic wave absorber | |
| US5185381A (en) | Foam absorber | |
| US20040020674A1 (en) | Composite EMI shield | |
| JP2005520331A (en) | Flame-retardant conductive EMI shielding material and method for producing the same | |
| WO2004032580B1 (en) | Emi-absorbing air filter | |
| WO1999013697A1 (en) | Nonflammable radio wave absorber | |
| US20030085050A1 (en) | EMI air filter | |
| EP0605784B1 (en) | Acoustic panel | |
| EP0140664A2 (en) | Radio wave shielding materials and a method of producing the same | |
| CN109468895B (en) | Vibration reduction and sound absorption assembly for track and assembly system with same | |
| DE4014453C2 (en) | Electrically conductive surface element and method for producing the same | |
| US20240209632A1 (en) | Roofing accessories with radiofrequency radiation shielding capabilities and methods of making and use thereof | |
| EP1028202B1 (en) | Heat and sound insulation element | |
| US5783080A (en) | Plate filter with high odor and toxin removing and water absorbing capacity and its manufacturing processes | |
| DE102009032497B4 (en) | Coordination of the sound reduction coefficient by distributed point masses | |
| CN211267566U (en) | Wave-absorbing composite layer | |
| JPS6058221A (en) | Filter material for filtering air | |
| CN112300598A (en) | Carbon fiber electromagnetic wave inhibiting material | |
| JP2000006115A (en) | Plate-like material or molding and manufacture thereof | |
| KR102290461B1 (en) | Cable tray having shielding functhion for electromagnetic wave and fire retardant, and manufacturing method thereof | |
| JPH10224078A (en) | Radio wave absorber | |
| JPH11340683A (en) | Manufacture of inorganic fiber web for electromagnetic wave absorber | |
| WO2004084602A1 (en) | Electromagnetic wave absorbing material and method for producing the same | |
| DE202005019726U1 (en) | Sheet material for insulation panels used in building construction, includes vapor phase coated metallic screening against high frequency electromagnetic radiation |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| AK | Designated states |
Kind code of ref document: A2 Designated state(s): AE AG AL AM AT AU AZ BA BB BG BR BY BZ CA CH CN CO CR CU CZ DE DK DM DZ EC EE EG ES FI GB GD GE GH GM HR HU ID IL IN IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MA MD MG MK MN MW MX MZ NI NO NZ OM PG PH PL PT RO RU SC SD SE SG SK SL SY TJ TM TN TR TT TZ UA UG US UZ VC VN YU ZA ZM ZW |
|
| AL | Designated countries for regional patents |
Kind code of ref document: A2 Designated state(s): GH GM KE LS MW MZ SD SL SZ TZ UG ZM ZW AM AZ BY KG KZ MD RU TJ TM AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LU MC NL PT RO SE SI SK TR BF BJ CF CG CI CM GA GN GQ GW ML MR NE SN TD TG |
|
| 121 | Ep: the epo has been informed by wipo that ep was designated in this application | ||
| DFPE | Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101) | ||
| B | Later publication of amended claims |
Effective date: 20040607 |
|
| ENP | Entry into the national phase in: |
Ref document number: 2006150599 Country of ref document: US Kind code of ref document: A1 |
|
| WWE | Wipo information: entry into national phase |
Ref document number: 10530110 Country of ref document: US |
|
| 122 | Ep: pct application non-entry in european phase | ||
| WWP | Wipo information: published in national office |
Ref document number: 10530110 Country of ref document: US |
|
| NENP | Non-entry into the national phase in: |
Ref country code: JP |
|
| WWW | Wipo information: withdrawn in national office |
Country of ref document: JP |