EP0248925B1 - Elektrostatischer Staubabscheider - Google Patents

Elektrostatischer Staubabscheider Download PDF

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Publication number
EP0248925B1
EP0248925B1 EP19860107877 EP86107877A EP0248925B1 EP 0248925 B1 EP0248925 B1 EP 0248925B1 EP 19860107877 EP19860107877 EP 19860107877 EP 86107877 A EP86107877 A EP 86107877A EP 0248925 B1 EP0248925 B1 EP 0248925B1
Authority
EP
European Patent Office
Prior art keywords
electrode
dust collector
electrostatic dust
filter element
collector according
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP19860107877
Other languages
English (en)
French (fr)
Other versions
EP0248925A1 (de
Inventor
Motoo Yanagawa
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
DKK Co Ltd
Original Assignee
Denki Kogyo Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to US06/869,784 priority Critical patent/US4662903A/en
Application filed by Denki Kogyo Co Ltd filed Critical Denki Kogyo Co Ltd
Priority to DE8686107877T priority patent/DE3667410D1/de
Priority to EP19860107877 priority patent/EP0248925B1/de
Publication of EP0248925A1 publication Critical patent/EP0248925A1/de
Application granted granted Critical
Publication of EP0248925B1 publication Critical patent/EP0248925B1/de
Expired legal-status Critical Current

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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
    • B03C3/34—Constructional details or accessories or operation thereof
    • B03C3/40—Electrode constructions
    • B03C3/60—Use of special materials other than liquids

Definitions

  • This invention relates to an electrostatic dust collector and, more particularly, to an electrostatic dust collector in which extremely small particles of dust can be collected efficiently with an easily replaceable filter, and wherein a short-circuit discharge caused by the application of a high voltage does not occur.
  • the dust collecting mechanisms employed in conventional air purifiers are classified roughly as being of the mechanical dust collecting or electrical dust collecting type, depending upon the operating principle.
  • the mechanical dust collecting systems are capable of trapping particles of a large diameter only and involve many difficulties in terms of installation and handling.
  • These days the electrical dust collectors are the most commonly employed.
  • Electrical dust collecting systems include electrostatic dust collectors in which dust is trapped electrostatically upon being ionized by a corona discharge, and electrostatic induction-type air purifiers in which an electric field is applied across an inductor and dust is passed through the inductor to be trapped electrostatically.
  • electrostatic dust collectors in which dust is trapped electrostatically upon being ionized by a corona discharge
  • electrostatic induction-type air purifiers in which an electric field is applied across an inductor and dust is passed through the inductor to be trapped electrostatically.
  • Fig. 1 is useful in describing the dust collecting principle of the electrostatic dust collector.
  • Floating particles contained in polluted air 1 pass through a filter 2 and are positively charged in a charging section 3 having a discharging wire 4 for effecting a corona discharge.
  • the positively charged particles enter a collecting section 5 where they are repelled by high-voltage electrode plates 6 and trapped by grounded electrode plates 7.
  • the apparatus thus provides purified air 8 from which the floating particles have been removed.
  • Fig. 2 is a sectional view illustrating an example of an electrostatic dust collector that employs the foregoing dust collecting principle.
  • the dust collector includes a unit in which are assembled a discharge wire 10 and a discharge electrode plate 11, both having a positive potential, and a dust collecting electrode plate 12 having a negative potential.
  • the unit is contained in a holder section 13 having a front side in which a front filter 14 is set, and a rear side in which a rear filter 15 and an activated carbon filter 16 for odor removal are installed.
  • the unit with the attached filters is installed in a casing 17 through an intake port covered by a grill 18.
  • a fan 19 and an outflow port 20 for the exiting air are provided in the rear portion of the casing 17.
  • Floating particles contained in polluted air are drawn in from the intake port by the fan 19, pass through the front filter 14 and are positively charged by the corona discharge wire 10.
  • the positively charged particles are repelled by the discharge electrode plate 11, the potential whereof is positive, and are trapped by the dust collecting electrode plate 12, whose potential is negative.
  • a stream of air so purified is blown out of the outflow port 20 upon passing through the rear filter 15 and activated carbon filter 16.
  • the electrostatic induction-type air purifier includes an air-permeable, porous inductor 30 on which opposing electrodes 31, 32 are disposed and across which a high DC voltage is impressed to produce a strong electric field in the inductor 30, thereby trapping floating particles which attempt to pass through the pores in the inductor.
  • the air purifier includes a filter element 41 arranged in the center of a case 40. Air containing pollutant particles is drawn into the case 40 from an inflow port 43 by a fan 42. To prevent the filter element 41 from becoming clogged, a filter bag 44 is disposed within the case 40 for trapping coarser dust particles.
  • the filter element 41 includes a filter member obtained by providing a thin film 48 of a metal such as aluminum comprising a first electrode on one side surface of a porous induction member 47 made of urethane foam or the like, and forming a metallic thin film 49 as a second electrode so that the induction member 47 is embraced by the electrodes. As shown in Fig.
  • a plurality of these filter members are wound into a cylindrical shape and a high voltage from a DC high-voltage power supply 45 (Fig. 4) is applied across the adjacent electrodes 48, 49 via terminals 48a, 49b.
  • Numeral 47a denotes a screen for supporting the filter element 41.
  • the electrostatic induction-type air purifier illustrated in Figs. 3, 5(a) and 5(b) also has a number of disadvantages.
  • An object of the present invention is to provide an electrostatic dust collector capable of collecting very fine dust efficiently without a short-circuit discharge caused by the application of a high voltage.
  • Another object of the present invention is to provide an electrostatic dust collector having an inexpensive filter element capable of being readily replaced.
  • a further object of the present invention is to provide an electrostatic dust collector which is low in cost and inexpensive to maintain.
  • an electrostatic dust collector comprising an electrode unit including first and second electrodes arranged to oppose each other across a solid insulator and having positive and negative potentials respectively applied thereto, the second electrode being so disposed that a leading edge portion thereof is located at a position inwardly of a leading edge portion of the first electrode; a gas passageway formed on a side of the second electrode opposite the first electrode; an electrically conductive filter element arranged in the gas passageway in contact with the second electrode; and forcible gas passing means for forcibly passing a gas to be purified through the gas passageway.
  • a ceramic 56 serving as a solid insulator is provided about a first electrode 50 to which a positive DC high voltage is applied.
  • a second electrode 52 to which a negative potential is applied is so provided as to sandwich the ceramic 56 between itself and the first electrode 50.
  • the first electrode 50, second electrode 52 and ceramic 56 thus arranged constitute an electrode unit.
  • the leading edge portion of the second electrode 52, namely the edge on the intake side of the apparatus, is located inwardly of the leading edge portion of the first electrode 50 so that the two edge portions do not overlap. The reason for this arrangement is to produce an edge effect on the intake side.
  • the edge effect sets up an electric field at this portion of the apparatus to guide floating particles into a filter element, described below.
  • a gas passageway 60 for a gas to be purified, such as air, is defined between two electrode units constructed as set forth above.
  • a filter element 61 which comprises a metal wool consisting of extremely fine fibers of steel, aluminum, copper or the like, by way of example.
  • the influx of floating particles is constricted when passing through the narrow voids formed by the fine pores in the mesh-like filter element, which is held at the negative potential, and the particles are caused to repeatedly collide with and contact one another, during which time they are charged.
  • the particles eventually are trapped on the metal fibers of the filter element 61 by Coulomb's force.
  • the trapped particles are held affixed by an electric charge supplied by the second electrode 52.
  • numeral 50 denotes the first electrode supplied with the positive DC high voltage
  • numeral 56 designates the ceramic 56 molded to enclose the first electrode 50.
  • These elements construct a first electrode unit Ui.
  • the leading edge portions of the second electrodes 52 are located inwardly of the leading edge portion of first electrode 50 so that an electric field is produced at these edge portions.
  • a second electrode unit U 2 is provided with the first electrode 50 supplied with a positive high voltage, the second electrode 52 supplied with a negative voltage, and the ceramic 56 embraced by these electrodes.
  • the first and second electrode units Ui, U 2 are assembled with a certain distance between them to form the passageway 60.
  • the dust collector can be designed to have a number of passageways suited to its capacity and application.
  • the filter element 61 is shaped beforehand so as to conform to the configuration of the passageway 60. It is also possible to employ a filter element of the kind depicted in Fig. 9(b).
  • the metal fibers of the filter element designated by numeral 62, are distributed coarsely at the leading edge portion, which is on the intake side of the passageway, but the distribution becomes gradually denser as the outflow side is approached. This makes it possible to collect a uniform amount of dust across the entirety of the filter element 62.
  • numeral 70 denotes the first electrode to which the positive DC high voltage is applied, 71 the second electrode to which the negative voltage is applied, and 72 the ceramic serving as the solid insulator enclosing the first electrode 70.
  • the electrodes 70, 71 and the ceramic 72 construct an electrode unit.
  • the leading edge portion of the second electrode 71 in the electrode unit is arranged at a position inwardly of the leading edge portion of the first electrode 70.
  • Numeral 73 denotes a side plate, 74 a gas passageway, 75 a filter element installed in the passageway 74, 76 a prefilter for trapping coarse dust particles in order to prevent clogging of the filter element 75, 77 a rear filter, which serves also as a holder for an activated carbon filter 78, 79 a case body, 80 a stopper, 81 a grill, 82 a fan, and 83 an outflow port.
  • the dust collecting unit accommodates the filter element 75, which comprises a metal wool of steel, aluminum, copper or the like, or a sponge consisting of an electrically conductive plastic.
  • the filter element 75 is shaped beforehand to conform to the configuration of the passageway 74 to facilitate its insertion into the passageway.
  • the assembled dust collecting unit inclusive of the filter element 75 is installed in the case body 79 by being pushed in from the intake port of grill 81 until it abuts against the stopper 80 located within the case body.
  • the fan 82 and the outflow port 83 for the purified air are provided in the rear portion of the case body 79 in back of the filter 78.
  • air or any other gas containing floating particles is drawn in through the grill 81 at the intake port by the fan 82.
  • the coarse particles are trapped by the prefilter 76.
  • the finer particles that pass through prefilter 76 are acted upon by the electric field at the leading edge portions of the electrodes 70, 71 to be guided into the filter element 75, which is held at the negative potential.
  • the entrant particles are subjected to the above-described dust collecting action and, hence, are trapped by the multiplicity of filter element fibers, which present a large surface area.
  • Air thus purified is deodorized by the activated carbon filter 78 before being blown out of the outflow port 83.
  • a first electrode 90 has a cylindrical configuration. Disposed on the inner surface of the first electrode 90 in coaxial relation with the first electrode is a cylindrical ceramic 92.
  • a second electrode 91 is formed on the inner surface of the ceramic 92 and has a cylindrical configuration, the second electrode being in coaxial relation with the ceramic 92.
  • the first and second electrodes 90, 91 are of cylindrical form and are disposed in coaxial relation with the cylindrical ceramic, which is sandwiched between them.
  • the leading edge portion of the second electrode 91 is located inwardly of the leading edge portion of the first electrode 91.
  • a space serving as a gas passageway 95, in which a filter element 96 shaped beforehand into a cylindrical configuration is arranged.
  • the first and second electrodes 90, 91 have terminals 93, 94, across which a high-voltage DC power supply 97 is connected.
  • a motor-driven fan 98 is arranged at the trailing ends of the electrodes. Operation is the same as that set forth above.
  • Figs. 13 and 14 only one electrode unit is shown. However, it is possible to adopt an arrangement in which a plurality of electrode units are disposed coaxially.
  • a centrally located cylindrical first electrode 100 a cylindrical ceramic 102 formed to enclose the first electrode 100, a second electrode 101 arranged on the inner circumferential surface of the ceramic 102, a second electrode 103 arranged on the outer circumferential surface of the ceramic 102, a cylindrical first electrode 104 provided on the outer side of the second electrodes 101, 103, a cylindrical ceramic 106 provided on the inner side of the first electrode 104, a cylindrical second electrode 105 provided on the inner side of the ceramic 106, a filter element 109 arranged in a central gas passageway 107 defined within the first electrode 100, and a filter element 110 arranged in a gas passageway 108 encircling the gas passageway 107 and coaxial therewith.
  • Numeral 111 denotes a motor-driven
  • the filter will act to chemically adsorb such compounds as S0 2 and NO x to achieve a greater degree of purification of the gas that passes through the filter element.
  • using steel wool allows the filter element to be employed in a high-temperature environment.
  • the magnitude and distribution of the electric field generated at the leading edge portion of the above-described electrode unit is dependent upon the voltage applied across the electrodes or the density of the fibers at the leading edge portion of the filter element.
  • the solid insulator has been described as being a ceramic, any material which exhibits a high insulation breakdown resistance and mechanical strength can be used.
  • One example is epoxy resin. If the latter is adopted, a slender electrode unit can be readily fabricated by forming an electrode comprising a thin metal film on the surface of a plate or sheet of the epoxy resin.

Landscapes

  • Electrostatic Separation (AREA)

Claims (11)

1. Ein elektrostatischer Staubscheider zum Entfernen von Teilchen aus einem zu reinigenden Gas mit: einer Elektrodeneinheit (U1, U2), die eine erste Elektrode (50; 70; 90; 100, 104), eine zweite Elektrode (52; 71; 91; 101, 103, 105) und festen Isolator (56; 72; 92; 102, 106) aufweist, wobei die erste und zweite Elektrode derart angeordnet sind, daß sie über dem festen Isolator gegenüberliegen, und an sie ein positives bzw. negatives Potential angelegt ist, wobei die zweite Elektrode so angeordnet ist, daß ein Vorderkantenabschnitt von ihr an einer Position in Richtung nach Innen von einem Vorderkantenabschnitt der ersten Elektrode liegt; einem Gasdurchgang (60; 74; 95; 107, 108), der auf einer der ersten Elektrode gegenüberliegenden Seite der zweiten Elektrode ausgebildet ist; einem elektrisch leitenden Filterelement (61, 62; 75; 96; 109, 110), das in dem Gasdurchgang derart angeordnet ist, daß es in Kontakt mit der zweiten Elektrode ist; und einer zwangsweisen Gasdurchleitvorrichtung (82; 98; 111) zum zwangsweisen Hindurchleiten von zu reinigendem Gas durch den Gasdurchgang.
2. Der elektrostatische Staubabscheider nach Anspruch 1, wobei eine Vielzahl von Staubabscheidereinheiten parallel zueinander benachbart angeordnet sind, wobei jede Staubabscheidereinheit aus der Elektrodeneinheit (U1, U2), dem Gasdurchgang (60; 74; 95; 107, 108) und dem Filterelement (61, 62; 75; 96; 109, 110) besteht.
3. Der elektrostatische Staubabscheider nach Anspruch 2, wobei die Vielzahl von parallel zueinander benachbart angeordneten Staubabscheidereinheiten eine Staubabscheidereinheit umfaßt, die an der Innenseite derselben angeordnet ist, wobei die erste Elektrode (100) der zuletzt genannten Staubabscheidereinheit in dem festen Isolator (102) eingeschlossen ist und die zweite Elektrode (101, 103) zu beiden Seiten des festen Isolators (102) angeordnet ist.
4. Der elektrostatische Staubabscheider nach Anspruch 1 oder 2, wobei die erste (50; 70) und zweite Elektrode (52; 71) ebene Platten sind, die parallel zueinander liegen.
5. Der elektrostatische Staubabscheider nach Anspruch 1 oder 3, wobei die erste (90; 100, 104) und zweite Elektrode (91; 101,103,105) Zylinder sind, die in koaxialer Beziehung angeordnet sind.
6. Der elektrostatische Staubabscheider nach einem der Ansprüche 1 bis 5, wobei das Filterelement (61, 62; 75; 96; 109, 110) vorgeformt ist, derart, daß es mit der Form des Gasdurchgangs (60; 74; 95; 107,108) übereinstimmt.
7. Der elektrostatische Staubabscheider nach einem der Ansprüche 1 bis 6, wobei das Filterelement Metallwolle, vorzugsweise aus Stahl aufweist.
8. Der elektrostatische Staubabscheider nach einem der Ansprüche 1 bis 7, wobei die zwangsweise Luftdurchleitvorrichtung (82; 98; 111) ein motorgetriebener Lüfter ist, der am hintersten Abschnitt des Gasdurchgangs (60; 74; 95; 107, 108) angeordnet ist.
9. Der elektrostatische Staubabscheider nach einem der Ansprüche 1 bis 8, ferner aufweisend ein Vorfilter (76), das am vorderen Abschnitt des Durchgangs (74) angeordnet ist, und/oder ein Aktivkohlefilter (78), das am hinteren Abschnitt des Gasdurchgangs (76) angeordnet ist.
10. Der elektrostatische Staubabscheider nach einem der Ansprüche 1 bis 9, wobei der feste Isolator (57; 72; 92; 102, 106) aus Keramik oder einem Epoxydharz besteht.
11. Der elektrostatische Staubabscheider nach einem der Ansprüche 1 bis 10, wobei ein Vorderkantenabschnitt der zweiten Elektrode (52; 71; 91; 101, 103, 105) an einem Abschnitt innerhalb eines Vorderkantenabschnitts der ersten Elektrode (50; 70; 90; 100, 102) angeordnet ist.
EP19860107877 1986-06-02 1986-06-10 Elektrostatischer Staubabscheider Expired EP0248925B1 (de)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US06/869,784 US4662903A (en) 1986-06-02 1986-06-02 Electrostatic dust collector
DE8686107877T DE3667410D1 (de) 1986-06-10 1986-06-10 Elektrostatischer staubabscheider.
EP19860107877 EP0248925B1 (de) 1986-06-10 1986-06-10 Elektrostatischer Staubabscheider

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP19860107877 EP0248925B1 (de) 1986-06-10 1986-06-10 Elektrostatischer Staubabscheider

Publications (2)

Publication Number Publication Date
EP0248925A1 EP0248925A1 (de) 1987-12-16
EP0248925B1 true EP0248925B1 (de) 1989-12-13

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ID=8195183

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19860107877 Expired EP0248925B1 (de) 1986-06-02 1986-06-10 Elektrostatischer Staubabscheider

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EP (1) EP0248925B1 (de)
DE (1) DE3667410D1 (de)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6480454A (en) * 1987-09-22 1989-03-27 Japan Res Dev Corp Dust collecting element for electrostatic precipitator and dust collecting method using said element
EP0425433A1 (de) * 1989-10-26 1991-05-02 Alusuisse-Lonza Services Ag Filtermaterial für die Ausfiltrierung von Russpartikeln
JP3062113B2 (ja) * 1997-04-16 2000-07-10 九州日本電気株式会社 ウェハー保管ボックス帯電化によるごみ付着防止機構
ITPD20110062A1 (it) * 2011-02-28 2012-08-29 Pierpaolo Garibaldi Dispositivo di filtraggio dell'aria applicabile a pensiline di attesa

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR963621A (de) * 1950-07-17
US2970670A (en) * 1958-08-06 1961-02-07 Honeywell Regulator Co Fluid cleaning apparatus
FR1400684A (fr) * 1964-05-27 1965-05-28 Nippon Kuki Kogyo Kabushiki Ka Dépoussiéreur d'air électrostatique
JPS52157651U (de) * 1976-05-25 1977-11-30
DE2658510A1 (de) * 1976-12-23 1978-06-29 Sachs Systemtechnik Gmbh Luftreinigungsgeraet

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Publication number Publication date
DE3667410D1 (de) 1990-01-18
EP0248925A1 (de) 1987-12-16

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