JP2007307550A - Electrostatic precipitator eliminating contamination of ground electrode - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrostatic precipitator reducing the contamination of a ground electrode by separating a charging stage and a collection stage. <P>SOLUTION: The electrostatic precipitator 100 for cleaning a gas blowing from the upstream to the downstream along a gas flow path 102 comprises a first zone 104 including a corona discharge ionization zone for making ions which charge a particle in gas in turn, and a second zone 106 including a collector zone located downstream of the first zone and collecting the charged particles. The precipitator 100 further comprises an anti-collector guide 108 preventing a collection of the charged particles in the first zone to direct the charged particles to flow to the second zone 106 downstream and collect the charged particles at the second zone, and a corona discharge electrode 110 for making an electrical field providing corona discharge ionization to the first zone 104 wherein the anti-collector guide 108 includes electrical field shielding which shields the charged particles from the electrical field in the first zone to prevent a collection of the charged particles in the first zone. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electrostatic precipitator or electrostatic system comprising an electrostatic crankcase ventilation system with a diesel engine for blowby gas to remove suspended particulate matter including oil droplets from the blowthrough gas. Regarding collectors.

  The electrostatic precipitator provided in the ventilation system of the electrostatic crankcase by a diesel engine is known as a prior art. In this simple form, a high voltage corona discharge electrode is placed in the center of a ground tube or canister that provides a collector electrode around the discharge electrode to form an annular ground plane. A high DC voltage of several thousand volts, for example, 15 kV, is applied to the central discharge electrode, causing a corona discharge near the electrode with high electric field strength. This electric field ionizes the gas in the corona discharge ionization zone to produce ions, creating electrically charged suspended particles in the gas. The charged particles are then electrostatically collected by an electric field on the inner surface of the collector tube or canister, ie, the surface attracted to the ground surface.

  Electrostatic collectors have been used for ventilation systems in diesel engine crankcases. To remove suspended particulate matter including oil droplets from the blow-by gas, for example, the blow-by gas can be returned to the atmosphere, or fresh air can be returned to the intake side of the diesel engine for further combustion, This provides a blow-by gas recirculation system. Oil mist is collected on a ground electrode provided by a canister, and the collected oil mist is discharged from the device.

(Parent application)
FIG. 1 shows a multi-stage space efficiency electrostatic collector 10 for cleaning gas flowing along gas flow paths indicated by arrows 12 and 14. The electrostatic collector can be attached to a mounting head 16 as shown in, for example, Patent Document 1 filed on April 8, 2004 by the same applicant, and the mounting head can be a diesel engine or an engine. It is attached to the internal combustion engine in the room. In the case of diesel engine exhaust, particulate matter containing oil droplets from the blow-by gas flows through the collector indicated by arrow 12 and is exhausted at arrows 14 and 18 for return to the engine or ventilation into the atmosphere. .

Particulate material, including collected oil droplets, is periodically discharged through the valve outlet 20, as is well known.
The electrostatic collector includes a canister 22 on the outer ground plane, an inner ground plane tube 24 shown in FIGS. 1-3, and a corona discharge electrode 26 disposed therebetween. In FIG. 3, the canister 22 is a cylindrical member that extends in the axial direction along the axis 28, and has an inner wall 34 that faces inwardly between the inlet end 30 and the outlet end 32 to provide a collector electrode. Yes.

  The corona discharge electrode 26 in the canister is provided by a hollow drum having an outer wall 36 extending axially along the axis 28 and facing the inner wall 34 of the canister, forming an outer annular channel 38 in the can. The drum has an inner wall 40 that forms a hollow interior chamber. The inner ground plane 24 is provided by a hollow cylinder extending in the canister axially from the inlet end 30 in the canister and further extending in the hollow inner chamber 42 in the axial direction. The hollow cylinder 24 has an outer wall 44 that faces the inner wall 40 of the drum 26 and forms an inner annular channel 46 in the can. The outer wall 44 of the hollow cylinder 24 provides a collector electrode. The hollow cylinder has an inner wall 48 that forms a hollow inner chamber 50 that provides an inner flow path.

  The gas to be cleaned enters the inlet fitting 52 as indicated by the arrow 12, and the first gas as indicated by the arrow 54 along the first flow path portion passing through the inner flow path along the hollow inner chamber 50 of the hollow cylinder 24. Flows upward in the axial direction. Further, the gas is reversed as indicated by an arrow 56 and flows in the axial direction 58 opposite to the second direction along the second flow path portion. An inner annular passage 46 extends between the outer wall 44 of the hollow cylinder 24 and the inner wall 40 of the drum 26. In addition, the gas reverses as indicated by arrow 60, passes through the outer annular passage 38 along the outer wall 36 of the drum 26 and the inner wall 34 of the canister 22, and as indicated by the arrow 62 along the third flow path portion. Flows upstream in one axial direction. The canister is closed at the top by an electrically insulative disk 64, which has a plurality of spaced openings 66 around the gas outlet passage. The gas passes through the plenum 68 toward the outlet port for the outlet channel, as indicated by arrow 14. The high voltage electrode 72 passes through the disk 64 and is electrically connected to the drum 26.

  In a preferred embodiment, the drum has a plurality of corona discharge elements, which are discharged by an inner discharge tip 74 that projects radially inward into the inner annular channel 46 toward the outer wall 44 of the hollow cylinder 24. Given. Such an inner discharge chip 74 protrudes into the second flow path portion 58 and is provided with a plurality of outer discharge chips 76, and the outer discharge chip is directed toward the inner wall 34 of the canister 22. 38 project radially outward. The outer discharge chip 76 protrudes into the third flow path portion 62 and is the same as that shown in Patent Document 2 filed on August 5, 2003 by the same applicant. The drum 26 is made of a metal or other conductive member or an insulator having a conductor portion connected to each chip. The outer annular channel 38 is coaxial with the inner annular channel 46 and is radially outward of it. The inner annular channel 46 is coaxial with the first channel 50 and is radially outward thereof. The gas flows through a tortuous path through the canister 22. The serpentine passage includes a first U-shaped curved portion 56 between the first and second flow path portions 54 and 58 and a second U-shaped curved portion 60 between the second and third flow path portions 58 and 62.

  This disclosed structure provides a multi-stage space efficient electrostatic collector for cleaning gas flowing along a gas flow path. The electrostatic collector includes a first stage provided by a first corona discharge zone 46 along the gas flow path, and a second stage along the gas flow path spaced along the gas flow path from the first corona discharge zone 46. A second stage provided by the corona discharge zone 38. The electrostatic collector is formed by a corona discharge electrode 26 and two ground planes 24.22. The first corona discharge zone 46 is between the corona discharge electrode 26 and the first ground plane 24. The second corona discharge zone 38 is between the corona discharge electrode 26 and the second ground plane 22. The second ground plane is formed by a canister 22 that extends in the axial direction along the axis 28.

  The corona discharge electrode is formed by a hollow drum 26 in a canister that extends axially along the axis 28. The first corona discharge zone 46 is inside the drum. The second corona discharge zone 38 is outside the drum. The first ground plane 24 is inside the drum. Each of the corona discharge electrode 26 and the second ground plane 22 has an annular shape, and each of the first and second corona discharge zones 46 and 38 has an annular shape. The ground plane 22 and the corona discharge zone 38, and the corona discharge electrode 26 and the corona discharge zone 46 are coaxially arranged. The corona discharge zone 46 concentrically surrounds the ground plane 24. The corona discharge electrode 26 concentrically surrounds the corona discharge zone 46. The corona discharge zone 38 concentrically surrounds the corona discharge electrode 26. The ground plane 24 is annular and forms the first gas flow zone 50 along the gas flow path at the position of the arrow 54. The ground plane 24 is separated from the first and second corona discharge zones 46 and 38 along the gas flow path. The ground plane 24 concentrically surrounds the initial gas flow zone 50. The gas flow direction is changed along the gas flow path at the position of the arrow 60 between the first and second corona discharge zones 46 and 38.

  Preferably, this change in direction is 180 °. The gas flow along the gas flow path flows along the first corona discharge zone 46, further reverses the direction at the position of the arrow 60, and flows in another flow direction 62 along the second corona discharge zone 38. The first and second corona discharge zones 46 and 38 are concentric with each other. The flow direction 62 is parallel to and opposite to the flow direction 58. The second corona discharge zone 38 surrounds the first corona discharge zone 46. The gas flow path has an initial gas flow zone at the location of reference numeral 50 before the gas flows through the first corona discharge zone 46. This initial gas flow zone 50 is a non-corona discharge zone. The gas flow path is a meandering path and includes an initial gas flow zone 50, a first corona discharge zone 46, and a second corona discharge zone 38. The gas flow path is located at a position 56 between the first gas flow zone 50 and the first corona discharge zone 46 and a position between the first flow inversion zone and the first corona discharge zone 46 and the second corona discharge zone 38. 60 has a second flow reversal zone. The gas flows in the flow direction 54 along the first gas flow zone 50, then reverses at position 56, further flows in the flow direction 58 along the first corona discharge zone 46, and reverses at position 60. And flows in the flow direction 62 along the second corona discharge zone 38. The flow direction 58 is parallel to and opposite to the flow directions 54 and 62. The first gas flow zone 50, the first corona discharge zone 46, and the second corona discharge zone 38 are concentric. The second corona discharge zone 38 surrounds the first corona discharge zone 46, and the first corona discharge zone 46 surrounds the initial gas flow zone 50.

The parent application of the present invention, filed April 8, 2004, provides a method for increasing the time remaining in a gas corona discharge zone flowing through an electrostatic collector. The collector directs the flow of gas along a first corona discharge path 58 through zone 46 and directs the flow of gas along a second corona discharge path 62 through zone 38. In the preferred method, the gas flow is directed along the first flow path 54 through the zone 50 in the electrostatic collector before directing the gas flow along the first corona discharge path 58.
US patent application Ser. No. 10 / 820,541 US patent application Ser. No. 10 / 634,565 US patent application Ser. No. 10 / 824,317

  The present invention has resulted from constant development efforts to obtain improved performance of electrostatic precipitators, which reduces ground electrode contamination and in diesel engine electrostatic crankcase ventilation systems. Collecting oil mist on a canister on an annular ground plane.

  An object of the present invention is to provide an electrostatic precipitator that reduces the contamination of the ground electrode by separating the charging stage and the collecting stage.

  In order to achieve the above object, the present invention is an electrostatic precipitator for cleaning a gas blown from upstream to downstream along a gas flow path, and creates ions that sequentially charge particles in the gas. A first zone comprising a corona discharge ionization zone and a second zone comprising a collector zone for collecting the charged particles are provided, wherein the second zone is downstream of the first zone.

  Charged particles are predominantly collected in the second zone rather than the first zone. The second zone is separated from and spaced from the first zone and is characterized by functionally separating the electrostatic precipitator ionization and collection stages as separate functions.

According to another configuration of the invention, an anti-collector guide is included in the first zone, the anti-collector guide prevents the collection of charged particles and instead flows the charged particles to the second zone downstream. And collecting the particles in the second zone.
The present invention also includes a corona discharge electrode that creates an electric field that provides corona discharge ionization in the first zone, and the anti-collector guide includes an electric field shield in the first zone to shield charged particles from the electric field, It is characterized by preventing collection of charged particles in the first zone.

The electric field shield divides the first zone into first and second sub-zones, the first sub-zone is on one side of the electric field shield, guides charged particles to the second zone, and the second sub-zone Located on the other side of the shield, between the corona discharge electrode and the electric field shield, provides ionization.
Furthermore, the first subzone, the second subzone, and the second zone are functionally separated into ionization, charging, and collection stages in an electrostatic precipitator, respectively.

  According to another configuration of the present invention, the electric field shield includes a perforated axial tube extending in the axial direction along the axis, and gas incident from the inlet end of the axial tube is opposed to the axial direction of the axial tube. The corona discharge electrode is composed of an axially extending hollow drum surrounding the axial tube, the first subzone is in the axial tube and the second subzone is outside the axial tube Between the axial tube and the drum, and the ions created by ionization in the second subzone pass through the perforations in the axial tube and charge the charged particles in the first subzone in the axial tube. The charged particles created and shielded by the axial tube from the electric field in the second subzone outside the axial tube created by the corona discharge electrode It is. The axial tube is at ground potential.

  According to another configuration of the invention, the outer zone includes an outer ground surface surrounding the drum, and the second zone is outside the drum and surrounds the drum and is between the drum and the outer ground surface. The outer ground plane includes a canister extending axially along an axis between a first axial end and a second axial end, the first axial end being both a gas inlet and a cleaned gas outlet. And the gas inlet is at the inlet end of the axial tube, and the cleaned gas outlet receives the cleaned gas from the second zone, and the gas enters the tube in the first axial direction from the gas inlet. Of the gas scrubbed from the second zone in the second axial direction, toward the radially outer second zone and opposite the first axial direction. It is characterized by flowing to the exit.

  According to another configuration of the present invention, it further includes a corona discharge electrode for generating an electric field in the first zone, the corona discharge electrode provides ionization by corona discharge, and one or more anti-collector guides are provided in the first zone. And venting the charged particles to prevent the charged particles from collecting in the first zone. The corona discharge electrode includes one or more corona discharge tips, each of which is disposed in one venturi tube, and performs ionization in an ionization zone in each venturi tube.

  It also includes a hollow drum that extends axially along the axis, forming and surrounding a first zone within the hollow drum, and the one or more venturi tubes accelerate charged particles along the axial direction. The drum has a drum inlet end that receives incoming gas and a drum outlet end that communicates with the second zone, and one or more venturi tubes are at the drum outlet end. One or more Venturi tubes are at ground potential.

  According to another configuration of the present invention, the drum has an outer ground surface surrounding the drum, and the second zone is outside the drum and surrounds the drum, and is located between the drum and the outer ground surface. The outer ground plane includes a canister extending axially along an axis between a first axial end and a second axial end, the first axial end having a gas inlet and a cleaned gas outlet. The gas passes through the first zone in the first axial direction from the gas inlet, through one or more venturi tubes in the drum, and further to the second zone outside in the radial direction, The cleaning gas flows from the second zone to the outlet of the cleaned gas in the second axial direction opposite to the first axial direction.

  According to another configuration of the present invention, an electrically conductive collection medium is included in the second zone between the drum and the outer ground plane, the electrically conductive collection medium being from a wire mesh and a metal honeycomb structure. Selected from the group consisting of The drum is an electrical insulator.

  The present invention can reduce the contamination of the ground electrode by separating the charging and collecting phases.

(Invention)
FIG. 4 shows an electrostatic precipitator 100 for cleaning gas flowing from upstream to downstream along the gas flow path 102. The gas flow path includes a first zone 104 and a second zone 106 that forms a corona discharge ionization zone that creates ions and then charges particles in the gas, and the second zone 106 is Forming a collection zone for collecting the charged particles.

The second zone 106 is downstream of the first zone 104, and the second zone 106 is spaced from the first zone 104 to functionally separate the electrostatic precipitator ionization and collection phases. Make it work. Charged particles are collected in the second zone 106 and are not collected in the first zone 104.
An anti-collector guide 108 is provided in the first zone 104 to prevent the collection of charged particles and instead directs the charged particles to the downstream second zone 106 for collection in the second zone.

  A corona discharge electrode 110 is provided in the first zone 104 and may include a discharge tip 112 that creates an electric field that provides corona discharge ionization. Anti-collector guide 108 is provided with an electric field shield in first zone 104 to shield charged particles from the electric field and prevent such charged particles from accumulating in first zone 104. The electric field shield 108 divides the first zone 104 into first and second subzones 114 and 116. The first subzone 114 is on one side of the electric field shield 108 and guides charged particles to the second zone 106. The second subzone 116 is on the other side of the electric field shield, and is located between the corona discharge electrode 110 and the electric field shield 108 to provide ionization. The first subzone 114, the second subzone 116, and the second zone 106 functionally separate the electrostatic precipitator and perform an ionization stage, a charging stage, and a collection stage, respectively.

  In a preferred form, the electric field shield 108 is a perforated tube, such as a screen, or other type of tube, extending axially along the axis 118 and directing the incoming gas at the reference numeral 120 to the axial tube. To the outlet end 124 of the axial tube located on the opposite side axially away from the inlet end 122 of the tube. The corona discharge electrode 110 is preferably a hollow drum that surrounds the tube 108 and extends in the axial direction. The first subzone 114 is in the tube 108. The second subzone 116 is outside the tube 108 and is located between the tube 108 and the drum 110. In the second subzone 116, the ions generated by ionization pass through the perforations in the tube 108 to produce charged particles in the first subzone 114 within the tube 108. The charged particles are shielded from the electric field created by the corona discharge electrode 110 by the tube 108 in the second subzone 116 outside the tube 108. The tube 108 is at ground potential.

  The outer grounding surface 126 surrounds the drum 110. The second zone 106 is outside the drum and surrounds the drum, and is located between the drum 110 and the outer ground plane 126. The outer ground plane 126 forms a canister extending axially along the axis 118 between the first and second axial ends 128, 130. The first axial end 128 has both a gas inlet 132 and a cleaned gas outlet 134. The gas inlet 132 is at the inlet end 122 of the axial tube. The cleaned gas outlet 134 receives the cleaned gas from the second zone 106. The gas passes through the first zone in the tube 108 in the first axial direction from the gas inlet 132 as indicated by the arrow 120 and through the outlet end 124 of the axial tube. Then, as indicated by an arrow 136, the second zone 106 is entered through the outside in the radial direction. Further, as shown by an arrow 138, the gas flows in the second axial direction opposite to the first axial direction and passes through the outlet 134 of the cleaned gas. The charged particles are collected in the second zone 106 by being attracted to the ground plane 126. From here, such contaminants are discharged from the lower drain 140.

  FIG. 5 illustrates another embodiment and uses reference numbers similar to those described above for ease of understanding. The electrostatic precipitator 150 has a corona discharge electrode formed by one or more discharge tips indicated by reference numeral 152, each tip being disposed in the first zone 154 to create an electric field to generate a corona discharge. Give ionization. The anti-collector guide described above is provided with one or more venturi tubes 156, each venturi tube accelerating charged particles in the first zone 154 and preventing these particles from collecting in the first zone. To do. Each of the one or more corona discharge tips is disposed within a respective venturi tube 156 and provides ionization in an ionization zone 154 within each venturi tube. A hollow drum 158 extends axially along the axis 118 and forms and surrounds a first zone within the drum. One or more Venturi tubes 156 then accelerate the charged particles in the axial direction as indicated by arrow 160. The drum 158 has an axial drum inlet end 162 that receives incoming gas and an axial drum outlet end 164 that communicates with the second zone 166, as indicated by arrow 120. One or more Venturi tubes 156 are at ground potential.

  The outer ground surface 126 surrounds the drum 158. The second zone 156 is outside the drum and surrounds the drum and is located between the drum 158 and the outer ground plane 126. The outer ground plane 126 forms a canister extending axially along the axis 118 between the first and second axial ends 128, 134. The first axial end 128 has both a gas inlet 132 and a cleaned gas outlet 134. The gas flows in the first direction from the gas inlet 132, as indicated by arrow 120, passes through the inside of the drum, and passes through the first zone 154 via one or more venturi tubes 156. Then, as indicated by an arrow 168, it flows radially outward and enters the second zone 166. Further, as indicated by an arrow 138, the gas flows in the second axial direction opposite to the first axial direction, passes through the second zone 166 and enters the cleaned gas outlet 134. The charged particles are collected in the second zone by being attracted to the ground plane 126. Such contaminants are then discharged from the canister to the lower drain 140 from the canister.

  FIG. 6 illustrates another embodiment and uses reference numerals similar to those described above for ease of understanding. An electrically conductive collection medium 180 is provided in the second zone 166 between the drum 158 and the outer ground plane 126. This electrically conductive collection medium is preferably a wire mesh, a metal honeycomb structure or the like. Such a medium comes into contact with the outer ground surface 126 and becomes a ground potential. As the charged particles enter the collection region 166 as indicated by arrow 168, these particles are collected in media 180. Diffusion is the first mechanism for this collection. The drum 158 is an electrical insulator.

  In the description above, certain terms have been used for simplicity, clarity, and understanding. The terms other than those obtained in the prior art do not include unnecessary limitations, and such terms are merely used for description and should be interpreted broadly. Configurations different from those described herein can be used with other configurations or alone. Various equivalents and alternatives and modifications are possible within the scope of the claims of the present invention.

It is a schematic perspective view of the electrostatic collector shown in the parent application of the present invention. It is a decomposition | disassembly block diagram of FIG. It is sectional drawing which shows the structure of the electrostatic collector of FIG. It is sectional drawing of the electrostatic precipitator according to this invention. It is sectional drawing similar to FIG. 4 which shows another embodiment. It is sectional drawing similar to FIG. 5 which shows another embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Electrostatic precipitator 102 Gas flow path 104,154 1st zone 106,166 2nd zone 108 Anti-collector guide 110 Corona discharge electrode 112,152 Discharge tip 114 1st subzone 116 2nd subzone 122 Inlet end of an axial direction tube 124 Outlet end of axial tube 126 Outer grounding surface 128 First axial end 130 Second axial end 156 Venturi tube 158 Hollow drum

Claims (21)

  An electrostatic precipitator for cleaning a gas blown from upstream to downstream along a gas flow path, the first zone comprising a corona discharge ionization zone for sequentially generating ions for charging particles in the gas; And a second zone comprising a collector zone for collecting charged particles, wherein the second zone is downstream of the first zone.   2. The electrostatic precipitator according to claim 1, wherein the charged particles are predominantly collected not in the first zone but in the second zone.   The second zone is separated from and spaced from the first zone, and functionally separates the electrostatic precipitator ionization and collection steps as separate functions. 1. The electrostatic precipitator according to 1.   Including an anti-collector guide in the first zone, the anti-collector guide preventing collection of the charged particles, and instead directing the charged particles to flow downstream into the second zone; The electrostatic precipitator according to claim 1, wherein the particles are collected in a second zone.   The first zone includes a corona discharge electrode that creates an electric field that provides the corona discharge ionization, and the anti-collector guide includes an electric field shield in the first zone to shield the charged particles from the electric field, The electrostatic precipitator according to claim 4, wherein the electrostatic precipitator prevents collection of the charged particles in the first zone.   The electric field shield divides a first zone into first and second sub-zones, the first sub-zone is on one side of the electric field shield, guides the charged particles to the second zone, and 6. The electrostatic precipitator according to claim 5, wherein the sub-zone is on the other surface side of the electric field shield, and is provided between the corona discharge electrode and the electric field shield to provide the ionization.   The first subzone, the second subzone, and the second zone are functionally separated into ionization, charging, and collection stages in the electrostatic precipitator, respectively. Item 6. The electrostatic precipitator according to Item 6.   The electric field shield comprises a perforated axial tube extending in an axial direction along an axis, and guides a gas incident from the inlet end of the axial tube to an axially opposite outlet end of the axial tube, The corona discharge electrode comprises an axially extending hollow drum surrounding the axial tube, the first subzone is in the axial tube, and the second subzone is outside the axial tube. Ions that are between the axial tube and the drum and are created by ionization in the second subzone pass through perforations in the axial tube and in the first subzone in the axial tube. Producing the charged particles, the charged particles being outside the axial tube produced by the corona discharge electrode; Electrostatic precipitator according to claim 6, characterized in that it is shielded by the axial tube from the electric field in the zone.   9. The electrostatic precipitator according to claim 8, wherein the axial tube has a ground potential.   9. The static circuit of claim 8, further comprising an outer grounding surface surrounding the drum, wherein the second zone is outside the drum, surrounds the drum, and is between the drum and the outer grounding surface. Electric dust collector.   The outer ground plane includes a canister extending axially along the axis between the first axial end and the second axial end, the first axial end being a gas inlet and cleaned gas The gas inlet is at the inlet end of the axial tube, the outlet of the cleaned gas receives the cleaned gas from a second zone, and the gas is supplied to the gas inlet Through the first zone in the tube in the first axial direction to the outlet end of the axial tube, and further toward the second zone on the radially outer side, opposite to the first axial direction. The electrostatic precipitator according to claim 10, wherein the electrostatic precipitator flows in an axial direction from the second zone to the outlet of the cleaned gas.   A corona discharge electrode that creates an electric field in the first zone, the corona discharge electrode provides ionization by the corona discharge, and the anti-collector guide includes one or more venturi tubes in the first zone; The electrostatic precipitator according to claim 4, wherein the charged particles are accelerated so that the charged particles do not collect in the first zone.   13. The corona discharge electrode includes one or more corona discharge tips, each of which is disposed in one venturi tube and performs ionization in an ionization zone in each venturi tube. Electrostatic precipitator.   A hollow drum extending axially along an axis, forming and surrounding the first zone in the hollow drum, the one or more venturi tubes accelerating the charged particles along the axial direction The electrostatic precipitator according to claim 13.   15. The drum has a drum inlet end for receiving incoming gas and a drum outlet end in communication with the second zone, and the one or more venturi tubes are at the drum outlet end. The electrostatic precipitator described.   15. The electrostatic precipitator of claim 14, wherein the one or more venturi tubes are at ground potential.   15. The outer ground surface surrounding the drum, wherein the second zone is outside the drum, surrounds the drum, and is located between the drum and the outer ground surface. The electrostatic precipitator described.   The outer ground plane includes a canister extending axially along the axis between the first and second axial ends, the first axial end being cleaned with a gas inlet. The gas passes through the first zone in a first axial direction from the gas inlet, through one or more of the venturi tubes in the drum, and further radially outward. 18. The electrostatic precipitator according to claim 17, wherein the electrostatic precipitator flows from the second zone to the outlet of the cleaned gas in a second axial direction opposite to the first axial direction. .   The electrostatic precipitator of claim 17, further comprising an electrically conductive collection medium in the second zone between the drum and the outer ground plane.   20. The electrostatic precipitator of claim 19, wherein the electrically conductive collection medium is selected from the group consisting of a wire mesh and a metal honeycomb structure. The electrostatic precipitator according to claim 19, wherein the drum is an electrical insulator.

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