WO1995027565A1 - Appareil et procede de separation electrostatique de particules - Google Patents

Appareil et procede de separation electrostatique de particules Download PDF

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Publication number
WO1995027565A1
WO1995027565A1 PCT/US1995/004183 US9504183W WO9527565A1 WO 1995027565 A1 WO1995027565 A1 WO 1995027565A1 US 9504183 W US9504183 W US 9504183W WO 9527565 A1 WO9527565 A1 WO 9527565A1
Authority
WO
WIPO (PCT)
Prior art keywords
electrode
fluid
outlet
particles
electrostatically charging
Prior art date
Application number
PCT/US1995/004183
Other languages
English (en)
Inventor
Chaim Gutfinger
David Pnueli
Mati Fichman
Leonid Moldavsky
Original Assignee
Technion Research & Development Foundation 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
Application filed by Technion Research & Development Foundation Ltd. filed Critical Technion Research & Development Foundation Ltd.
Publication of WO1995027565A1 publication Critical patent/WO1995027565A1/fr

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Classifications

    • 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
    • B03C3/66—Applications of electricity supply techniques
    • 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
    • B03C3/06—Plant or installations having external electricity supply dry type characterised by presence of stationary tube electrodes
    • 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
    • B03C3/45—Collecting-electrodes
    • B03C3/53—Liquid, or liquid-film, electrodes

Definitions

  • the present invention relates to a filtering method and apparatus, and particularly to an electrostatic filtering method and apparatus for separating particles from a fluid stream.
  • the particles may be solid particles, liquid drops, soft doughlike particles, melted material, etc.; and the fluid may be gaseous, vapor, or liquid, or a mixture of these.
  • Conventional mechanical filters include a fluid-permeable filtering element across the outlet which removes the particles from the fluid stream flowing through the outlet.
  • the particles thus accumulate in the fluid-permeable filtering element and must therefore be periodically removed (as by mechanical shaking, water rinsing, or the like), or the filtering element must be periodically replaced.
  • An object of the present invention is to provide a filtering method and apparatus free from the need for periodical cleaning or replacing the filtering element.
  • a method for separating particles from a fluid stream which flows along a flow path from an inlet to an outlet comprising: electrostatically charging the particles with charges of one polarity while the fluid stream flows through an electrostatically charging zone in the flow path; locating a fluid-permeable electrode across the outlet; and electrostatically charging the fluid- permeable electrode with a charge of the same polarity as the charged particles to repel from the fluid outlet the charged particles in the fluid flowing through the fluid- permeable electrode to the fluid outlet.
  • the invention also provides apparatus for separating particles from a fluid stream in accordance with the above method.
  • the method and apparatus of the present invention are effective to block the particles from reaching the filtering element, such as the fluid-permeable electrode which also serves as the filtering element, or a separate mechanical filtering element provided on the downstream side of such a fluid-permeable electrode, thereby eliminating the need for periodically cleaning the filtering element or periodically replacing it.
  • the present invention is to be sharply distinguished from the conventional electrostatic filtering or precipitation method.
  • the particles are electrostatically charged with charges of one polarity, and the precipitating electrode is electrostatically charged with a charge of the opposite polarity to attract the charged particles thereto; but such a method does not include a fluid-permeable electrode across the outlet which is electrostatically charged with a charge of the same polarity as the charged particles to repel from the fluid outlet the charged particles in the fluid flowing through the fluid-permeable electrode.
  • the novel method of the present invention is also to be sharply distinguished from that described in Arbesi US Patent 5,203,993, Yeh US Patent 4,066,526, and Masuda US Patent 3,930,815.
  • the Arbesi patent relates to a method and apparatus for removing salt from sea water in which a repelling electrode is also provided carrying a charge of the same polarity as that on the particles, but there the repelling electrode is located parallel to the outlet and not across the outlet.
  • the Yeh patent relates to a method which also includes a repelling electrode, but the same electrode also produces a corona discharge for electrostatically charging the particles.
  • the method of the Masuda patent also includes repelling electrodes for repelling the particles, but there the repelling electrodes are located in the path of the fluid stream, and not across the fluid outlet to block the fluid particles from reaching the fluid outlet.
  • Fig. 1 schematically illustrates one form of filtering apparatus constructed in accordance with the present invention.
  • Fig. 2 schematically illustrates a second form of filtering apparatus constructed in accordance with the present invention.
  • the filtering apparatus illustrated in Fig. 1 comprises a housing, generally designated 10, formed with one or more inlets 11 , and one for more outlets 12.
  • the housing further includes a blower 13 for producing a fluid stream of a gas (e.g., air) containing particles which are to be removed from the fluid stream before reaching the outlet 12.
  • a gas e.g., air
  • housing 10 further includes one or more electrostatically charging electrodes 14 for electrostatically charging the particles with charges of one polarity while the fluid stream flows through an electrostatically charging zone defined by these electrodes towards the outlet 12.
  • the filter further includes a fluid- permeable electrode 15 adjacent to and across the fluid outlet 12, such that the flow path of the fluid stream from the inlet 11 to the outlet 12 must pass through it.
  • Housing 10 further includes a precipitating electrode 16 on the opposite side of the inlets 11, i.e., out of the flow path of the fluid stream as it flows from the inlet 11 towards the outlet 12.
  • Precipitating electrode 16 is electrically insulated from electrodes 14 and 15; it receives a charge of the opposite polarity from those electrodes.
  • electrode 16 When housing 10 is made of conducting material and is grounded, electrode 16 is either insulated from housing 10, or it may be connected to housing 10, i.e., grounded and not charged separately.
  • a layer of water 17 is applied over precipitating electrode 16. As will be described below, the particles in the fluid stream are attracted towards precipitating electrode 16 and precipitate on the water layer 17 thereover, which facilitates the removal of the precipitating particles.
  • Water layer 17 may be a static layer, but preferably is a circulating layer so as to continuously remove the precipitating particles.
  • electrodes 14 and 15 are connected to a common voltage source via line 18 and lead- through insulator 10a.
  • Precipitating electrode 16 when not grounded, is connected to another common voltage source via line 19.
  • the voltage sources of the two lines 18 and 19 are of opposite polarity.
  • line 18 connected to electrodes 14 and 15 is of negative polarity
  • line 19 connected to the precipitating electrode 16 is of ground or positive polarity.
  • Electrodes 14 produce a corona discharge to thereby electrostatically charge the particles in the fluid stream with one polarity, in this case negative polarity, as the fluid stream flows through an electrostatically charging zone between inlet 11 and the fluid-permeable electrode 15.
  • Electrode 15 is of the same polarity as the charges applied to the particles, and thereby repels the particles so that only the fluid, without the particles, passes through the fluid-permeable electrode 15 to the outlet 12.
  • An electrode 14a enclosing the electrostatically charging zone between inlets 11 and the fluid-permeable electrode 15, is connected to the latter two electrodes and thereby also repels the particles, so that the particles will not precipitate on electrode 14a.
  • the precipitating electrode 16 is of the opposite polarity as that of the charged particles and therefore attracts the charged particles towards it. These particles are deposited on the water layer 17 over electrode 16. If layer 17 is a static layer, the particles with the water may be periodically removed; and if it is a flowing layer, the particles with the water are continuously removed.
  • Fig. 2 illustrates another construction of electrostatic filter which operates basically in the same manner as described above with respect to Fig. 1.
  • the filtering apparatus illustrated in Fig. 2 also includes a housing, generally designated 20, with an inlet 21 at one end and an outlet 22 at the other end.
  • a blower 23 located at the inlet end of the housing produces a fluid stream of a gas (e.g., air) containing particles (e.g., dust) flowing from the inlet 21 through the housing and its outlet 22.
  • a gas e.g., air
  • particles e.g., dust
  • An electrostatic-charging electrode 24 is located within housing 20 and extends continuously from its inlet 21 to its outlet 22.
  • a fluid-permeable electrode 25 is located across the outlet 22 so as to extend across the fluid stream path through the housing 20.
  • the fluid-permeable electrode 25 is electrically connected to the electrostatic charging electrode 24 and therefore is at the same potential as that electrode.
  • Housing 20 is made of metal and encloses the fluid flow path through the housing. It is electrically insulated from the fluid-permeable electrode 25 by an electrical insulator 27, and is of the opposite polarity as electrostatic electrode 24 and the fluid-permeable electrode 25. As shown in Fig. 2 for purposes of example, the fluid- permeable electrode 25 and the electrostatically-charging electrode 24 connected thereto are connected to an electrical conductor 28 of negative polarity; whereas the metal housing 20 is connected to electrical conductor 29 of ground (or positive) polarity.
  • Electrode 24 produces a corona discharge which electrostatically charges the particles in the fluid stream flowing through the housing 20 with charges of negative polarity.
  • the complete volume within the housing 20 serves as an electrostatic charging zone for charging the particles in the fluid stream with charges of negative polarity.
  • Housing 20, being of metal and charged with the opposite polarity, serves as an annular (circular or other geometrical shape) precipitating electrode located around the electrostatic charging zone and attracts thereto the negatively-charged particles in the fluid stream.
  • the particles P within the fluid stream are repelled by both the charging electrode 24 and the fluid-permeable electrode 25, and are attracted by the precipitating electrode 20. These particles therefore traverse the trajectories shown by the curved lines T to precipitate on the inner surface of the precipitating electrode 20.
  • the particles within the fluid stream in the structure of Fig. 2 are blocked from flowing through the fluid-permeable electrode 25 to the outlet 22, and precipitate on the precipitating electrode, in this case the inner surface of the metal housing 20.
  • the fluid- permeable electrode, 15 and 25, respectively may also serve as the filter element defining the filtering passageways through which the particle-free air passes to the outlet.
  • conventional mechanical filter elements could be applied on the downstream side of these fluid-permeable electrodes to serve as the filtering passageways. In either case, there will be no accumulation of particles on the filtering element so that there will be no need to clean or replace it.

Landscapes

  • Electrostatic Separation (AREA)

Abstract

Procédé et appareil de séparation de particules d'un courant fluidique. Ce procédé consiste à: appliquer aux particules une charge électrostatique (14) d'une polarité tandis que le courant fluidique s'écoule à travers une zone de charge électrostatique (10) située dans la trajectoire d'écoulement; placer une électrode perméable aux fluides (15) en travers de l'orifice de sortie (12); et appliquer une charge électrostatique (18) de la même polarité que celle des particules chargées à l'électrode perméable aux fluides (15) afin de repousser, de l'orifice de sortie de fluide (12), les particules chargées dans le fluide qui s'écoule à travers ladite électrode (15) vers ledit orifice (12).
PCT/US1995/004183 1994-04-08 1995-04-04 Appareil et procede de separation electrostatique de particules WO1995027565A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IL109,265 1994-04-08
IL109265A IL109265A (en) 1994-04-08 1994-04-08 Electrostatic device and method for separating particles from liquid stream

Publications (1)

Publication Number Publication Date
WO1995027565A1 true WO1995027565A1 (fr) 1995-10-19

Family

ID=11066011

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1995/004183 WO1995027565A1 (fr) 1994-04-08 1995-04-04 Appareil et procede de separation electrostatique de particules

Country Status (2)

Country Link
IL (1) IL109265A (fr)
WO (1) WO1995027565A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103586129A (zh) * 2013-10-31 2014-02-19 汉王科技股份有限公司 静电空气净化装置及方法
WO2014127434A1 (fr) * 2013-02-21 2014-08-28 Kovachki Hristo Atanasov Procédé et dispositif pour la purification électrochimique-par plasma de gaz effluents
GB2528939A (en) * 2014-08-06 2016-02-10 Univ Staffordshire Electrostatic precipitator
WO2017055207A1 (fr) * 2015-09-29 2017-04-06 Renishaw Plc Appareil et procédé de fabrication d'additif

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3930815A (en) * 1971-05-12 1976-01-06 Senichi Masuda Electrostatic apparatus for removing entrained particulate material from a gas stream
US4066526A (en) * 1974-08-19 1978-01-03 Yeh George C Method and apparatus for electrostatic separating dispersed matter from a fluid medium
US5084078A (en) * 1990-11-28 1992-01-28 Niles Parts Co., Ltd. Exhaust gas purifier unit
US5203993A (en) * 1991-10-29 1993-04-20 Electrostat Technologies, Inc. Method and apparatus for removing salt from sea water

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3930815A (en) * 1971-05-12 1976-01-06 Senichi Masuda Electrostatic apparatus for removing entrained particulate material from a gas stream
US4066526A (en) * 1974-08-19 1978-01-03 Yeh George C Method and apparatus for electrostatic separating dispersed matter from a fluid medium
US5084078A (en) * 1990-11-28 1992-01-28 Niles Parts Co., Ltd. Exhaust gas purifier unit
US5203993A (en) * 1991-10-29 1993-04-20 Electrostat Technologies, Inc. Method and apparatus for removing salt from sea water

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014127434A1 (fr) * 2013-02-21 2014-08-28 Kovachki Hristo Atanasov Procédé et dispositif pour la purification électrochimique-par plasma de gaz effluents
CN103586129A (zh) * 2013-10-31 2014-02-19 汉王科技股份有限公司 静电空气净化装置及方法
GB2528939A (en) * 2014-08-06 2016-02-10 Univ Staffordshire Electrostatic precipitator
WO2017055207A1 (fr) * 2015-09-29 2017-04-06 Renishaw Plc Appareil et procédé de fabrication d'additif

Also Published As

Publication number Publication date
IL109265A0 (en) 1994-07-31
IL109265A (en) 1998-04-05

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