US3841840A - Electrostatic filter - Google Patents

Electrostatic filter Download PDF

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Publication number
US3841840A
US3841840A US00275685A US27568572A US3841840A US 3841840 A US3841840 A US 3841840A US 00275685 A US00275685 A US 00275685A US 27568572 A US27568572 A US 27568572A US 3841840 A US3841840 A US 3841840A
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United States
Prior art keywords
electrostatic filter
electrodes
air
housing
insert
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Expired - Lifetime
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US00275685A
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English (en)
Inventor
C Cobarg
H Boehm
E Hundhausen
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Individual
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C3/00—Separating dispersed particles from gases or vapour, e.g. air, by electrostatic effect
    • B03C3/02—Plant or installations having external electricity supply
    • B03C3/04—Plant or installations having external electricity supply dry type
    • B03C3/14—Plant or installations having external electricity supply dry type characterised by the additional use of mechanical effects, e.g. gravity
    • B03C3/155—Filtration

Definitions

  • No.: 275,685 ises has electrodes separated by a substance which permanently adsorbs or absorbs the particles carried by the air, or converts them into innocuous com- [30] Forelgn Apphcat lon Pnomy Dam pounds by a chemical transformation or reaction, so July 28, 1971 Austria 6576/71 as to prevent h particles f b i returned to h ambient air when the appliance is switched off.
  • Substance may, f r l b e having a large sur- 55/132 55/135 55/155 face area, such as activated carbon, kieselguhr zoltile, [51] f Cl B03c 3/00 B03: 3/01 9/00 gels or the like, or an oxidizing or reducing agent, e.g., 2 2 .E'E'QPEFEH$LQE$Z 2Q potassium permanganate or sodium persulphate, and 557124 132, 134, 143, may be applied in the form ofa surface layer either to 154 at least one of the electrodes or to a spacer element therebetween.
  • an oxidizing or reducing agent e.g., 2 2 .E'E'QPEFEH$LQE$Z 2Q potassium permanganate or sodium persulphate
  • auxiliary heating may be provided if neces- UNITED STATES PATENTS sary.
  • the spacer element if provided, may be corru- 1,964,794 7 1934 Gilbert 23/284 gated or folded so as to increase its Surface area, the 2,974,747 3 1961 Coolidge, Jr et 1 air passing along the corrugations or folds. 3,665,679 5/1972 McLain et al. 55 124 x 8 Cl 6 D F.
  • snmeurz CONVOLUTED ASSEMBLY OF ELECTRODES AND INSERT LADEN WITH ACTIVE SUBSTANCE Fl'g6 i /L Z Fig5 ELECTROSTATIC FILTER Our present invention relates to electrostatic filters for air purification, a term here understood in the general sense as the cleaning of air for breathing in enclosed spaces, by the removal of all kinds of matter suspended therein such as organic or inorganic dust, smoke particles and molecules of chemical compounds, particularly of aromatic and aliphatic hydrocarbons.
  • the electrostatic-filtering technology has so far essentially been developed for application in technical production establishments, particularly for cleaning of flue gases of heating appliances, blast-furnace gas and the like.
  • the apparatus concerned is technically very elaborate and permanently installed in the smoke currents.
  • the electrostatic filter has also been applied to the improvement and cleaning of air in industrial and residential premises, for which purpose a fan causes air containing charged particles to flow under pressure or suction between filter electrodes to which a high D. C. potential is applied.
  • the advantages of the electrostatic filter reside in its low resistance to flow and its high yield, even in the case of the smallest particles of the order of 10*;1. in size.
  • the low flow resistance makes it possible to obtain an air throughput which is of adequate proportions for residential and industrial premises, even with small fans and low electricpower consumption.
  • the large bandwidth of the filtering enables removal for the air to.be breathed even of suspended and olfactory matter whose presence, de-
  • the object of the invention is therefore to improve the known electrostatic filter for the purpose of air cleaning in such a way that molecules of organic compounds which have been separated out either cannot re-evaporate from the filter electrodes or can do so only in an innocuous form.
  • the space between confronting electrodes of opposite polarity in an electrostatic filter of the kind hereinbefore described is partly occupied by active substances which permanently adsorb, or absorb and/or convert into innocuous compounds by a chemical transformation, the particles moving to the filter electrodes in the D. C. field.
  • active substances which permanently adsorb, or absorb and/or convert into innocuous compounds by a chemical transformation, the particles moving to the filter electrodes in the D. C. field.
  • innocuous we mean such compounds which, as previously mentioned, have no adverse effect either on health or on comfort.
  • the insert acting as a carrier for that substance, the insert lying with its major surfaces parallel to the direction of the air flow circulating through-the intervening space; these major surfaces and the electrode faces define a plurality of unobstructed parallel channels through which the air can pass in'contact with the active substance carried thereon.
  • the insert could be disposed with clearance parallel to the electrode faces; more advantageously, the insert is an undulating strip of sheet material with fold lines parallel to the flow direction contacting the electrode faces whereby the strip also acts as a spacer.
  • Such an assembly of two electrodes and an interposed undulating spacer, laden with purifying agent can also be convoluted to form a cylindrical filter cartridge. If desired, either or both electrode faces may also be coated with purifying agent.
  • active substances usable as purifying agents in a system according to our invention there are first of all purely mechanically adsorbent substances having a large surface area, such as activated carbon, kieselguhr, zoelite, gels and the like; furthermore, particularly for the removal of the heavy molecules of aromatic compounds with unpleasant odors, all compounds which have an oxidizing or reducing effect thereon, preferably suchvwhich can be applied at room temperature in the presence of a catalyst so-called cold combustion or in special cases also such substances which have to be separately heated up to an elevated reaction temperature, may be used.
  • Suitable purifying agents of the oxidizing type include potassium permanganate and sodium persulphate.
  • a layer of dielectric is created betweenthe polarized'filter electrodes. This establishes certain 'electrical criteria for a suitable active substance i.e., that its dielectric losses be low and likewise its dielectric constant, so that the DC. field acting on the air passing through the filter and on theparticles contained therein is substantially formed in the residual free air gap between the filter electrodes.
  • the invention makes it possible to use electrostatic filters as in intermittently operated appliances for air cleaning in enclosed'space's either'exclusively or in addition to the conventional dust filters in which the current of air is transverse thereto, and to utilize the great advantages of electrostatic filters from the point of view of power consumption and the bandwidth of their specific effectiveness, without the filtered-off particles returning to the ambient air between periods of operation.
  • the insert laden therewith may be regenerated or cleaned and reloaded or, if neither is possible, replaced by a fresh insert.
  • FIG. 1 shows a layer-carrying filter electrode
  • FIG. 2 shows an insert spacedly disposed in an air gap between two filter electrodes
  • FIG. 3 shows a modification of the arrangement of FIG. 2
  • FIG. 4 is a fragmentary perspective view, partly in section, of a portable air-cleaning appliance equipped with an electrostatic filter embodying our invention.
  • FIG. is an axial sectional view, taken on the line V V of FIG. 6, of another filter-equipped appliance.
  • FIG. 6 is a cross-sectional view taken on the line VI VI of FIG. 5.
  • FIG. I a section of a filter electrode 1 which here plate-shaped, is shown which defines an outer electrode of a set of electrodes and which has a layer of an active substance or purification agent 2, e.g. activated carbon, on its surface confronting an associated counterelectrode (not shown).
  • an active substance or purification agent 2 e.g. activated carbon
  • the filter electrode may be in the form of a metal plate, a metallized plastic plate or a foil and may preferably be in the form of a grid, whose interstices are filled with the active substance, or a metallized fabric, which is impregnated with the active substance.
  • the active substance may also be conductive.
  • FIG. 2 shows an arrangement of the active substance on a carrier 4 inserted in the air gap 5 between the filter electrodes 1 and 3 of opposite polarity.
  • the carrier is constructed in the manner hereinbefore described with reference to the electrode 1 of FIG. 1.
  • FIG. 3 shows a modification of the assembly of FIG. 2; here the carrier 6 for the active substance is arranged in undulating manner'in the air gap 5 for the purpose of increasing its surface and makes alternate line contact with the electrodes 1, 3.
  • the carrier 6 may, for example, consist of corrugated paper which has been impregnated with the active substance before or after its installation between the filter electrodes, or it may consist of a fabric which inherently has the required rigidity or which acquires it only after impregnation with the active substance.
  • FIG. 4 shows a cross-section through a portable aircleaning appliance of a form which is known (per se e.g. as known from German Pat. specification No. l,2l2,703) for electrical auxiliary heating appliances for residential or working premises.
  • a so-called cross-flow fan is provided, i.e., a fan whose cylindrical rotor, provided with blades 110, has the air current passing through it twice.
  • the air is sucked in through a grid 13 in the housing 11, and through a mechanical segregating filter 14 for coarse dust, hair, threads and the like, in the direction of the arrow F,
  • the carrier 17 may also, after a period 'of time in which the active sub stances have become spent, be exchanged.
  • FIG. 4 shows only diagramatically the preferably transportable air-cleaning appliance equipped with our improved electrostatic filter.
  • the stand or foot of the appliance which may be arranged on the underside of the housing 10, the motor which drives the fan shaft 111, and the supply unit which produces the high tension for the filter elec trodes l, 3 from an A.C. supply; the motor and the supply unit may, for example, be arranged on the end faces of the housing 10.
  • means may also be provided in the discharge channel of the fan for heating, and humidifying the cleaned air.
  • FIGS. 5 and 6 we have shown an appliance having a substantially cylindrical housing 20 to which an air current is applied axially, the latter being produced by an axial fan having a propeller 21 and a motor 22.
  • the air is aispirated through an intercepting grid 23, and moves through the mechanical coarse filter 14, past the discharge electrodes 16 and then through a cluster of filter cartridges 24, shown in outline and arranged symmetricallyin a circle with their axes parallel to that of housing'20.
  • the cartridges 24 have a coiled structure of the type illustrated in FIG. 3.
  • the cleaned ajr leaves the housing20 through a discharge grid 25.
  • FIG. 6 shows detail of the discharge side of the appliance;
  • the core of the appliance in the region of the filter cartridges 24 is taken up by a high-voltage power supply 26 (not shown in FIG. 6).
  • a high-voltage power supply 26 not shown in FIG. 6
  • the core space may also be occupied by a further filter cartridge and the power pack may be accommodated, for example, in the stand (not shown).
  • our invention displays considerable versatitlity and may be incorporated in a great variety of differently constructed appliances.
  • the active sub stance and/or its carrier may also be heated directly or indirectly, e.g. by the provision of a heating resistance for the filter electrodes or of heating registers in the low-pressure chamber 18 (FIG. 4) or in the discharge channel upstream of the filter.
  • An electrostatic filter comprising:
  • a foil-shaped insert disposed between said electrodes with major surfaces parallel to the direction of said flow, said major surfaces defining with said confronting faces a plurality of substantially unobstructed parallel channels, said insert being laden with a purifying agent exposed to the air flow along said major surfaces.
  • An electrostatic filter as defined in claim 4 wherein said electrodes and said insert are convoluted into a substantially cylindrical cartridge with an axis parallel to said direction of flow.
  • An electrostatic filter comprising a plurality of substantially cylindrical cartridges as defined in claim 5, a common housing for said cartridges and circulation means common to said cartridges in said housing.
  • An electrostatic filter as defined in claim 6 wherein said housing is substantially cylindrical and open at both ends of the cylinder, said cartridges being clustered in said housing with their axes parallel to the housing axis, said circulation means comprising'an axially oriented fan disposed near one of said ends.

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  • Electrostatic Separation (AREA)
US00275685A 1971-07-28 1972-07-27 Electrostatic filter Expired - Lifetime US3841840A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
AT657671A AT320088B (de) 1971-07-28 1971-07-28 Elektrostatisches Filter

Publications (1)

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US3841840A true US3841840A (en) 1974-10-15

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Application Number Title Priority Date Filing Date
US00275685A Expired - Lifetime US3841840A (en) 1971-07-28 1972-07-27 Electrostatic filter

Country Status (8)

Country Link
US (1) US3841840A (it)
AT (1) AT320088B (it)
CH (1) CH541997A (it)
DE (1) DE2234179A1 (it)
FR (1) FR2147254B1 (it)
GB (1) GB1394227A (it)
IT (1) IT963063B (it)
SE (1) SE378764B (it)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4376642A (en) * 1980-08-18 1983-03-15 Biotech Electronics Ltd. Portable air cleaner unit
US4405342A (en) * 1982-02-23 1983-09-20 Werner Bergman Electric filter with movable belt electrode
US4725411A (en) * 1985-11-12 1988-02-16 W. R. Grace & Co. Device for physical and/or chemical treatment of fluids
US4941962A (en) * 1985-06-17 1990-07-17 Noboru Inoue Electrostatic adsorptive fluid filtering apparatus
WO1998039100A1 (en) * 1997-03-05 1998-09-11 Eurus Airtech Ab Device for air cleaning
US6361589B1 (en) * 1997-08-06 2002-03-26 Eurus Airtech Ab Device for air cleaning
WO2002076619A1 (fr) * 2001-03-27 2002-10-03 Obschestvo S Ogranichennoi Otvetstvennostju 'obnovlenie' Dispositif d'epuration d'air permettant d'eliminer la poussiere et les aerosols
US20040206732A1 (en) * 2003-04-21 2004-10-21 Brask Justin K. Method and apparatus for particle removal
US20070186778A1 (en) * 2005-05-25 2007-08-16 Dust Control Technology, Inc. System and method for suppressing dust and odors
US20100026967A1 (en) * 2007-01-26 2010-02-04 Panasonic Corporation Powder dust capture device and projection type image display device
US8070744B1 (en) * 2008-02-01 2011-12-06 Clements Clara C Nasal aspiration device
US9005347B2 (en) 2011-09-09 2015-04-14 Fka Distributing Co., Llc Air purifier

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH629684A5 (de) * 1977-05-12 1982-05-14 Manfred R Burger Verfahren und elektrostatische filtervorrichtung zur reinigung von gasen.
US5143552A (en) * 1988-03-09 1992-09-01 Tokyo Electron Limited Coating equipment
SE9303059D0 (sv) * 1993-09-17 1993-09-17 Purocell Sa Anordning vid ett elektrostatiskt filter och en anläggning innefattande åtminstone en sådan anordning

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1964794A (en) * 1931-10-20 1934-07-03 Meyer D Gilbert Smoke treating apparatus
US2974747A (en) * 1956-03-20 1961-03-14 Borg Warner Electric precipitators
DE1212703B (de) * 1959-06-06 1966-03-17 Braun Ag Ortsveraenderlicher Raumluefter
US3665679A (en) * 1970-01-28 1972-05-30 Air Control Ind Inc Electrostatic air cleaner

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1964794A (en) * 1931-10-20 1934-07-03 Meyer D Gilbert Smoke treating apparatus
US2974747A (en) * 1956-03-20 1961-03-14 Borg Warner Electric precipitators
DE1212703B (de) * 1959-06-06 1966-03-17 Braun Ag Ortsveraenderlicher Raumluefter
US3665679A (en) * 1970-01-28 1972-05-30 Air Control Ind Inc Electrostatic air cleaner

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4376642A (en) * 1980-08-18 1983-03-15 Biotech Electronics Ltd. Portable air cleaner unit
US4405342A (en) * 1982-02-23 1983-09-20 Werner Bergman Electric filter with movable belt electrode
US4941962A (en) * 1985-06-17 1990-07-17 Noboru Inoue Electrostatic adsorptive fluid filtering apparatus
US4725411A (en) * 1985-11-12 1988-02-16 W. R. Grace & Co. Device for physical and/or chemical treatment of fluids
WO1998039100A1 (en) * 1997-03-05 1998-09-11 Eurus Airtech Ab Device for air cleaning
US6398852B1 (en) 1997-03-05 2002-06-04 Eurus Airtech Ab Device for air cleaning
US6361589B1 (en) * 1997-08-06 2002-03-26 Eurus Airtech Ab Device for air cleaning
US20040052700A1 (en) * 2001-03-27 2004-03-18 Kotlyar Gennady Mikhailovich Device for air cleaning from dust and aerosols
WO2002076619A1 (fr) * 2001-03-27 2002-10-03 Obschestvo S Ogranichennoi Otvetstvennostju 'obnovlenie' Dispositif d'epuration d'air permettant d'eliminer la poussiere et les aerosols
US6893618B2 (en) 2001-03-27 2005-05-17 Gennady Mikhailovich Kotlyar Device for air cleaning from dust and aerosols
US20040206732A1 (en) * 2003-04-21 2004-10-21 Brask Justin K. Method and apparatus for particle removal
US6924456B2 (en) * 2003-04-21 2005-08-02 Intel Corporation Method and apparatus for particle removal
US20070186778A1 (en) * 2005-05-25 2007-08-16 Dust Control Technology, Inc. System and method for suppressing dust and odors
US20100026967A1 (en) * 2007-01-26 2010-02-04 Panasonic Corporation Powder dust capture device and projection type image display device
US8172406B2 (en) * 2007-01-26 2012-05-08 Panasonic Corporation Powder dust capture device and projection type image display device
US8070744B1 (en) * 2008-02-01 2011-12-06 Clements Clara C Nasal aspiration device
US9005347B2 (en) 2011-09-09 2015-04-14 Fka Distributing Co., Llc Air purifier
US9914133B2 (en) 2011-09-09 2018-03-13 Fka Distributing Co., Llc Air purifier

Also Published As

Publication number Publication date
IT963063B (it) 1974-01-10
FR2147254A1 (it) 1973-03-09
GB1394227A (en) 1975-05-14
FR2147254B1 (it) 1977-11-18
CH541997A (de) 1973-09-30
SE378764B (it) 1975-09-15
AT320088B (de) 1975-01-27
DE2234179A1 (de) 1973-02-08

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