JP2020069409A - Charging device and dust collector - Google Patents

Abstract

To provide a charging device which can adequately remove dust attached to a ground electrode.SOLUTION: A charging device 10 charges dust contained in dust-containing air by corona discharge while circulating the dust-containing air, and includes: a plurality of discharge electrodes 50 supported by a support body 40; a ground electrode 32 which is arranged with a clearance to generate corona discharge with each of the discharge electrodes 50; and an air jetting part 34 which sprays compressed air to the ground electrode 32 from a direction intersecting a circulation direction of the dust-containing air circulated through the clearance between the discharge electrodes 50 and the ground electrode 32, and sweeps off the dust attached to the ground electrode 32. A plurality of circulation holes H for passing the compressed air sprayed from the air jetting part 34 are formed on the ground electrode 32.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a charging device and a dust collector.

  There is known a charging device that charges particles in dust-containing air by corona discharge.

  For example, the electrode part of the pre-charging part described in Patent Document 1 is connected to the support, a plurality of projecting discharge electrodes supported by the support, a flat ground electrode having a plurality of holes, and the support. It was equipped with a high voltage power supply. The ground electrode was arranged parallel to the flow direction of the fuel exhaust gas. Further, a partition and a damper are provided on the upstream side of the electrode portion in the flow direction of the fuel exhaust gas, and the control unit controls the opening degree of the damper to change the flow rate (flow amount) of the fuel exhaust gas. It was

International Publication No. 2011/152357

  In the electrode portion described in Patent Document 1, in order to remove the dust attached to the ground electrode by the flow of the fuel exhaust gas, the opening degree of the damper is controlled to increase the flow amount of the fuel exhaust gas. However, when the flow rate of the fuel exhaust gas is increased, the dust enters deep inside the filter, which causes a problem that the filter is easily clogged. Further, for example, when sticky dust adheres to the ground electrode, it may not be possible to remove the dust only by increasing the flow rate of the fuel exhaust gas.

  In order to solve the above problems, the present invention provides a charging device and a dust collecting device that can properly remove dust adhering to a ground electrode.

  A first charging device of the present invention is a charging device that charges dust contained in dust-containing air by corona discharge while circulating dust-containing air, and includes a plurality of discharge electrodes supported by a support. , A ground electrode provided with a gap for generating a corona discharge between each of the discharge electrodes, and a flow direction of dust-containing air flowing through the gap between the discharge electrode and the ground electrode An air jetting portion that blows compressed air to the ground electrode from a direction intersecting with the air electrode to blow off dust adhering to the ground electrode, wherein the ground electrode is compressed air blown from the air jetting portion. There are formed a plurality of flow holes for passing through.

  In the first charging device of the present invention, the air jetting portion blows the compressed air in a direction intersecting the flow direction of the dust-containing air. According to this configuration, the blown compressed air can blow off the dust (particles) attached to the ground electrode while passing through the flow hole of the ground electrode. Thus, the dust attached to the ground electrode can be properly removed. Further, it is possible to prevent troubles such as dust removed from the ground electrode flowing downstream in the flow direction of the dust-containing air and clogging a filter provided on the downstream side of the charging device. As a result, stable performance of the ground electrode, the filter, etc. can be maintained for a long period of time.

  A second charging device of the present invention is the above-described first charging device, further comprising an inner cylindrical body formed in a cylindrical shape with both end surfaces in the flow direction of the dust-containing air closed, and the ground electrode, The support body is formed in a tubular shape extending in the flow direction of the dust-containing air, and is provided on the same axial center as the inner tubular body with a gap between them on the outer side in the radial direction with respect to the inner tubular body. It is preferably formed in a cylindrical shape extending in the flow direction of the dust-containing air and arranged in the gap between the ground electrodes.

  According to the second charging device of the present invention, since both end surfaces of the inner cylindrical body are closed, the inflow of dust-containing air into the inner cylindrical body which is not the charging area (area where corona discharge occurs) is prevented. Can be prevented.

  According to a third charging device of the present invention, in the above-mentioned second charging device, the air ejecting portion has the inner cylinder formed with a plurality of ejection ports, which are ejection ports of compressed air toward the ground electrode, on a peripheral wall. It is preferable to include a body, an air supply pipe for guiding compressed air into the inner cylindrical body, and an adjusting valve for adjusting the amount of compressed air passing through the air supply pipe.

  According to the third charging device of the present invention, the compressed air supplied from the air supply pipe to the inner cylindrical body can be ejected from the ejection port of the inner cylindrical body radially outward (direction intersecting the flow direction). it can. This allows dust adhering to the ground electrode to be blown outward in the radial direction.

  A fourth charging device of the present invention is the above-mentioned third charging device, wherein the compressed air blown out from the ejection port corresponds to a downstream side of the ground electrode in the flow direction of the dust-containing air with respect to the discharge electrode. It is preferable to be sprayed toward the position.

  By the way, the dust in the dust-containing air is charged in the process of passing through the charging region formed between the discharge electrode and the ground electrode, and the charged dust adheres to the ground electrode. Therefore, the charged dust easily adheres to the ground electrode on the downstream side of the support and the discharge electrode. In this respect, according to the fourth charging device of the present invention, it is possible to blow the compressed air to a portion of the ground electrode where dust is likely to adhere. As a result, it is possible to efficiently remove dust from the ground electrode. Further, it is possible to prevent the compressed air from being directly blown onto the discharge electrode. As a result, it is possible to prevent the discharge electrode from being bent or bent by blowing compressed air.

  A fifth charging device of the present invention is the charging device according to any one of the above-mentioned second to fourth, wherein the aperture ratio of the ground electrode is set to be larger than that of the ground electrode arranged radially outward. Is preferred.

  According to the fifth charging device of the present invention, since the aperture ratio of the ground electrode arranged on the outer side in the radial direction is set to be larger than the aperture ratio of the ground electrode arranged on the inner side in the radial direction, the outer side in the radial direction is set. It is possible to increase the air flow rate (circulation rate) of the compressed air passing through the ground electrode arranged at. This makes it possible to make the air volume of the compressed air passing through the radially inner ground electrode and the air volume of the compressed air passing through the radially outer ground electrode substantially uniform. That is, the dust removal effect of the compressed air can be made to act substantially uniformly on the plurality of ground electrodes arranged in the radial direction.

  A sixth charging device of the present invention is the charging device according to any one of the second to fifth charging devices, wherein the plurality of ground electrodes are outer ground electrodes, and are radially outer than the inner cylindrical body, and are outer. The inner ground electrode is arranged radially inward with respect to the ground electrode with a gap therebetween, and the gap between the outer ground electrode and the inner ground electrode is bisected in the radial direction. An inner side ground electrode, and, between the outer side ground electrode and the middle side ground electrode, an outer flow path for circulating dust-containing air is formed, and the inner side ground electrode and the middle side ground electrode It is preferable that an inner flow path that allows the dust-containing air to flow is formed therebetween, and the support body that supports the discharge electrode is disposed in the outer flow path and the inner flow path.

  According to the sixth charging device of the present invention, since a plurality of charging regions can be formed in the two flow paths, the outer flow path and the inner flow path, even if a large amount of dust-containing air is made to flow, dust can be generated. It can be appropriately charged. Further, since the middle ground electrode divides one flow path into two equal parts, the outer flow path and the inner flow path are formed to have the same width in the radial direction. According to this configuration, the discharge electrodes having the same charging performance can be arranged in the two flow passages, the outer flow passage and the inner flow passage. As a result, one type of discharge electrode can be used, and the manufacturing cost can be reduced as compared with the case of using two or more different types of discharge electrodes. Further, since one type of discharge electrode is used, one power source can be shared by a plurality of discharge electrodes, which also leads to a reduction in manufacturing cost.

  In a seventh charging device according to the present invention, in the sixth charging device described above, the number of the support bodies arranged is set so that the number of the outer flow passages is greater than that of the inner flow passages. preferable.

  In the seventh charging device of the present invention, since the outer flow passage is located radially outward of the inner flow passage, the cross-sectional area of the outer flow passage has an inner flow when viewed from the flow direction of the dust-containing air. It is made larger than the cross-sectional area of the road. Therefore, the flow rate of the dust-containing air in the outer flow passage is larger than that in the inner flow passage. Further, a larger number of supports are arranged in the outer flow passage than in the inner flow passage. According to this configuration, more discharge electrodes can be arranged in the outer flow path than in the inner flow path, and more charged regions can be formed in the outer flow path than in the inner flow path. As a result, the dust can be appropriately charged in the outer flow path through which a large amount of dust-containing air flows.

  An eighth charging device of the present invention is the above-mentioned sixth or seventh charging device, wherein the support arranged in the outer flow path and the support arranged in the inner flow path are dust-containing. It is preferable that they are arranged at the same position in the air flow direction.

  In the eighth charging device of the present invention, the plurality of supports arranged in the radial direction are arranged at the same position in the flow direction of the dust-containing air. With this configuration, for example, at a position displaced from the support in the flow direction, compressed air can be blown to the plurality of radially arranged ground electrodes at the same position in the flow direction. Further, by arranging a plurality of support bodies arranged in the radial direction at the same position in the flow direction, as compared with the case where the support bodies are displaced in the flow direction, the space for arranging the support, that is, the length in the flow direction of the ground electrode Can be shortened.

  A ninth charging device of the present invention is the above-described eighth charging device, which is formed in a tubular shape with both end surfaces in the flow direction of dust-containing air open, and the inner cylinder is located radially outside the outer ground electrode. An outer cylinder body disposed on the same axis as the body and an insulator, formed through the outer cylinder body and the outer ground electrode in a radial direction, and having its tip end portion arranged in the outer flow path. An outer power feeding insulator to be brought into contact with the support, an outer power feeding member that radially penetrates the inside of the outer power feeding insulator, and electrically connects the support disposed in the outer flow path to a power source; Is formed of a body and radially penetrates the outer cylindrical body, the outer ground electrode, the support body arranged in the outer flow path, and the middle ground electrode, and a tip portion thereof is arranged in the inner flow path. An inner power feeding insulator to be brought into contact with the support, and an inner power feeding insulator The penetrating in the radial direction, it is preferable that further comprising an inner power supply member to electrically connect the said support located on the inner channel power.

  According to the ninth charging device of the present invention, even if a plurality of supports are arranged side by side in the radial direction at the same position in the flow direction of the dust-containing air, power can be supplied to the inside support. .. In addition, since power can be supplied to the supports arranged on the outer side and the inner side in the radial direction, corona discharge can be generated from each discharge electrode supported on each support, and the two flow paths can be used. Charged areas can be formed.

  A tenth charging device of the present invention is the above-mentioned ninth charging device, further comprising a connecting member that is provided at an upstream end portion of the outer cylindrical body and the inner cylindrical body in a flow direction of dust-containing air. It is preferable that the connecting member, the outer power feeding insulator, and the inner power feeding insulator are provided at positions overlapping with each other when viewed from the flow direction of the dust-containing air.

  In the tenth charging device of the present invention, the connecting member is provided on the upstream side in the flow direction with respect to the outer power feeding insulator and the inner power feeding insulator, and the connecting member and each power feeding insulator are arranged in the circumferential direction when viewed from the flow direction of the dust-containing air. It was arranged to be in phase with. According to this configuration, the dust contained in the dust-containing air mainly collides with the connecting member and is less likely to collide with each power insulator hidden behind the connecting member. As a result, the amount of dust attached to the surface of each power insulator can be reduced, and the occurrence of creeping leak can be suppressed.

  According to an eleventh charging device of the present invention, in any one of the first to tenth charging devices described above, it is preferable that the discharge electrode is formed by bundling a plurality of fibrous line electrodes.

  According to the eleventh charging device of the present invention, since the fibrous line electrode is used as the discharge electrode, it is possible to generate the corona discharge with a lower applied voltage as compared with the case of using the thick electrode. As a result, it is possible to suppress the generation of sparks and also suppress the generation of ozone due to the ionization of air. Further, since the plurality of line electrodes are used as the discharge electrodes, even if some of the line electrodes are worn, corona discharge can be continuously generated in the remaining line electrodes.

  A twelfth charging device according to the present invention is the charging device according to any one of the first to eleventh aspects, wherein the voltage applied between the discharge electrode and the ground electrode is 4 kV or more and 6 kV or less, The surface of the ground electrode is preferably coated with fluorocarbon resin having conductivity.

  According to the twelfth charging device of the present invention, the adhesion of dust can be suppressed by coating the ground electrode with the fluororesin. Further, it is possible to easily remove dust attached to the ground electrode (coating). Further, by setting the applied voltage to 4 to 6 kV, damage / deterioration of the coating of the ground electrode can be suppressed.

  A first dust collecting device of the present invention is provided in any one of the first to twelfth charging devices, and is provided on a downstream side of the charging device in a circulation direction of dust-containing air, and collects dust charged by the charging device. The air ejecting unit includes: a collecting device that collects by a filter; and a backwashing device that removes dust collected by the filter by blowing compressed air supplied from a compressed air source toward the filter. Removes dust adhering to the ground electrode by compressed air supplied from the compressed air source.

  According to the first dust collector of the present invention, since the backwash device and the air jetting unit share one compressed air source, a part of the pipe extending from the compressed air source, a regulator (pressure regulator), etc. Can be shared. As a result, the structure of the compressed air supply system can be simplified and the manufacturing cost can be reduced.

  According to the present invention, dust attached to the ground electrode can be properly removed.

It is a perspective view which shows the dust collector which concerns on one Embodiment of this invention. It is a perspective view showing a charging device concerning one embodiment of the present invention. FIG. 3 is a perspective view showing a state in which the outer cylindrical body of the charging device according to the embodiment of the present invention is removed. FIG. 3 is a perspective view showing a state in which an outer cylindrical body and an outer ground electrode of the charging device according to the embodiment of the present invention are removed. FIG. 3 is a perspective view showing an inner cylinder body, an inner ground electrode, and the like of the charging device according to the embodiment of the present invention. It is a side view which shows the charging device which concerns on one Embodiment of this invention. FIG. 7 is a sectional view taken along line VII-VII in FIG. 6. It is a block diagram which shows the charging device which concerns on one Embodiment of this invention. FIG. 6 is a cross-sectional view for explaining a dust collecting operation of the dust collecting device and a dust removing operation of the charging device according to the embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, "Fr" shown in each figure shows "front", "Rr" shows "rear", "L" shows "left", "R" shows "right", and "U" shows. "Up" is shown, and "D" shows "down". In this specification, terms indicating directions and positions are used for convenience of description, but these terms do not limit the technical scope of the present invention.

[Configuration of dust collector]
The dust collecting apparatus 1 according to the embodiment will be described with reference to FIG. 1. FIG. 1 is a perspective view showing the dust collector 1.

  The dust collector 1 is a device that charges and collects dust in dust-containing air by corona discharge. For example, the dust collector 1 is installed in a factory that performs metal processing using a plasma processing machine or a laser processing machine. Further, for example, the dust collector 1 collects fine dust such as metal fumes generated during metal processing. The dust collector 1 can be installed not only in a metalworking factory but also in a place where dust is generated. The dust collected by the dust collector 1 is not limited to metal fumes, and may be of any type as long as it can be charged and collected.

  The dust collector 1 includes a charging device 10, a collection device 20, a backwash device 25, and an electrical component section 70. The charging device 10 has a function of charging the dust contained in the dust-containing air by corona discharge while circulating the dust-containing air. The collecting device 20 is provided on the downstream side of the charging device 10 in the flow direction of the dust-containing air, and has a function of collecting the dust charged by the charging device 10 by the filter 23. The backwash device 25 has a function of removing the dust collected in the filter 23 by blowing compressed air supplied from the compressor 3 (compressed air source) to the filter 23 (hereinafter, also referred to as “backwash”). is doing. The electrical component section 70 has a function of controlling the supply of electric power required to drive the dust collector 1. In the following description, the “circulation direction” refers to the direction in which the dust-containing air flows. Further, the terms "upstream" and "downstream" and similar terms refer to "upstream" and "downstream" in the flow direction of the dust-containing air and similar concepts.

[Charging device]
The charging device 10 has a substantially cylindrical appearance that extends in the left-right direction (circulation direction). The charging device 10 is fixed to the left side surface of a dust collecting housing 21 of the collecting device 20 described later. An intake duct 2 for guiding dust-containing air into the charging device 10 is connected to the left end surface (upstream side) of the charging device 10. An inspection port 2A for inspecting the upstream side of the charging device 10 is formed in the intake duct 2 so as to be opened and closed. Although details will be described later, a plurality of ground electrodes 32, a plurality of discharge parts 33, and the like are provided inside the charging device 10.

[Collecting device]
The collection device 20 includes a dust collection housing 21 having a substantially rectangular parallelepiped appearance. The dust-collecting case 21 is provided with a partition plate 22 made of metal (for example, stainless steel) that divides the internal space into two parts in the vertical direction. The inner space of the dust-collecting housing 21 is partitioned by a partition plate 22 into a lower dirty room R1 and an upper clean room R2. In addition, in FIG. 1, in order to show the inside of the clean room R2, the upper part of the dust collection housing 21 is shown by a virtual line (two-dot chain line).

  Six filters 23 are supported in the dirty room R1 in a state of being suspended from the partition plate 22. The filter 23 includes a pleated non-woven fabric (made of synthetic resin fiber) having a plurality of folds. The filter 23 is formed in a substantially cylindrical shape, and the upper end surface of the filter 23 is open. The partition plate 22 is formed with six partition openings 22A arranged in two rows in the front-rear direction and three rows in the left-right direction. The six filters 23 are supported by the partition plate 22 in correspondence with the six partition openings 22A, and the upper openings of the filters 23 are exposed to the clean room R2 through the partition openings 22A.

  Further, a filter inspection opening 21A for opening the dirty room R1 is formed on the lower side of the front surface of the dust collecting housing 21. Further, a filter inspection door (not shown in FIG. 1 since it has been removed) for opening and closing the filter inspection opening 21A is attached to the dust collection housing 21. In addition, below the dirty room R1 of the dust collection housing 21, a bucket (not shown) for storing the fallen dust is provided.

  The above-described charging device 10 is directly connected to the left side surface of the dust collection housing 21 and communicates with the dirty room R1 without passing through a duct or the like, but indirectly with the dust collection housing 21 through a duct or the like. May be connected.

  Further, an exhaust port 24 communicating with the clean room R2 is opened on the upper surface of the dust collection housing 21, and an exhaust duct (not shown) is connected to the exhaust port 24. An exhaust fan (not shown) for exhausting the air in the dust collection housing 21 and a control unit 6 (see FIG. 8) are provided in the exhaust duct or the clean room R2. The air may be exhausted to the outside of the dust collection casing 21 without connecting the exhaust duct.

[Backwash device]
The backwash device 25 includes a header tank 26, three blow tubes 27, and three backwash valves 28.

  The header tank 26 is a cylindrical pipe extending in the left-right direction in the clean room R2. The header tank 26 is arranged on the front side of the partition plate 22 so as to avoid the partition opening 22A. Compressed air supplied from the compressor 3 is stored inside the header tank 26. The left end portion of the header tank 26 is connected to the compressed air introduction port 26A formed on the left side surface of the dust collection casing 21. An external pipe 4 extending from the compressor 3 (compressed air source) provided in the factory is connected to the outside of the compressed air introduction port 26A. A regulator 5 for adjusting the pressure of the compressed air supplied from the compressor 3 is interposed in the external pipe 4.

  The three blow tubes 27 are connected to the header tank 26 via the three backwash valves 28. The three blow tubes 27 extend rearward from the header tank 26 at positions corresponding to the partition openings 22A arranged in three rows in the left-right direction. Each of the blow tubes 27 is arranged so as to cross the two partition openings 22A (filter 23) arranged in the front-rear direction. Two blowout ports 27A for blowing out the compressed air supplied from the compressor 3 are formed on the lower surface of each blow tube 27. The two outlets 27A are opened at positions corresponding to (substantially the centers of) the two partition openings 22A arranged in the front-rear direction. The backwash valve 28 is a solenoid valve that adjusts the amount of compressed air supplied to the blow tube 27. Specifically, the backwash valve 28 is opened under the control of the control unit 6, so that the compressed air in the header tank 26 flows into the blow tube 27, and from the outlet 27A toward the upper surface opening of the filter 23. Blown out.

[Configuration of charging device]
Next, the configuration of the charging device 10 will be described in detail with reference to FIGS. 2 to 8. FIG. 2 is a perspective view showing the charging device 10. FIG. 3 is a perspective view showing a state where the outer cylindrical body 30 of the charging device 10 is removed. FIG. 4 is a perspective view showing a state where the outer cylinder body 30 and the outer ground electrode 321 of the charging device 10 are removed. FIG. 5 is a perspective view showing the inner cylindrical body 31 and the inner ground electrode 323 of the charging device 10. FIG. 6 is a side view showing the charging device 10. FIG. 7 is a sectional view taken along line VII-VII in FIG. FIG. 8 is a block diagram showing the charging device 10.

  As shown in FIG. 2, the charging device 10 includes an outer cylinder body 30, an inner cylinder body 31, three ground electrodes 32, five discharge parts 33, and an air ejection part 34.

<External cylinder>
As shown in FIG. 2, the outer cylindrical body 30 is formed in a substantially cylindrical shape with both end surfaces in the left-right direction (circulation direction of dust-containing air) open so as to form the outer shape of the charging device 10. The outer cylindrical body 30 is made of, for example, a metal material such as stainless steel, and is electrically connected to the ground. A pair of flange portions 30F that spreads radially outward is formed at both ends in the left-right direction (axial direction) of the outer tubular body 30. The outer cylinder body 30 is connected to a suction port (not shown) of the dust collection housing 21 via the right flange portion 30F (see FIG. 1). The outer tubular body 30 is connected to the intake duct 2 via the left flange portion 30F (see FIG. 1).

<Inner cylinder>
As shown in FIGS. 2 and 5 to 7, the inner cylindrical body 31 is formed in a substantially cylindrical shape having a smaller diameter than the outer cylindrical body 30 and shorter than the outer cylindrical body 30 in the axial direction. The inner tubular body 31 is arranged inside the outer tubular body 30 with a space interposed between the inner tubular body 31 and the inner peripheral surface of the outer tubular body 30. The inner tubular body 31 is arranged at a position not exposed in the axial direction from the outer tubular body 30 and on the same axis as the outer tubular body 30. The inner cylindrical body 31 is formed of, for example, a metal material such as stainless steel. The inner cylindrical body 31 is formed in a substantially cylindrical shape with both axial end faces closed. As will be described later in detail, a plurality of ejection ports 63 that serve as blowout ports for compressed air are formed on the peripheral wall of the inner cylindrical body 31.

(Connecting member)
A pair of connecting members 35 are provided on both left and right ends of the outer tubular body 30 and the inner tubular body 31 described above. The left and right end surfaces of the inner tubular body 31 are closed by a pair of connecting members 35 (see FIG. 7). Each connecting member 35 is formed of a conductive metal material, and the inner cylindrical body 31 is electrically connected to the ground by being connected to the outer cylindrical body 30 via the connecting member 35. Since the pair of connecting members 35 have substantially the same shape, one connecting member 35 will be described below.

  As shown in FIG. 6, the connecting member 35 includes a substantially disc-shaped closing portion 35A and a pair of connecting arms 35B extending from the closing portion 35A to the front and rear sides. The closing portion 35A is formed in a circular shape having substantially the same diameter as the outer diameter of the inner cylindrical body 31. The closing portion 35A is arranged so as to close the open end surface of the inner tubular body 31, and is screwed to a pair of receiving portions 31P formed at both front and rear edges of the inner tubular body 31. The pair of connecting arms 35B are formed in a substantially strip shape, and are bridged between the inner cylindrical body 31 and the outer cylindrical body 30. The pair of connecting arms 35B are screwed to the pair of receiving portions 30P formed on both front and rear edges of the outer tubular body 30. Further, a conical portion 36 formed in a substantially conical shape is screwed to the closed portion 35A of the left (upstream) connecting member 35 (see FIG. 7 and the like).

<Ground electrode>
As shown in FIGS. 2, 3 and 6, the three ground electrodes 32 (outer ground electrode 321, middle ground electrode 322, inner ground electrode 323) are respectively arranged in the left-right direction (circulation direction of dust-containing air). It is formed in an extended substantially cylindrical shape. The three ground electrodes 32 are arranged radially inward of the outer tubular body 30 and radially outward of the inner tubular body 31 with a gap therebetween and on the same axis as the inner tubular body 31. That is, the three ground electrodes 32 have different outer diameters and are arranged concentrically when viewed in the axial direction (circulation direction). The axial length of each ground electrode 32 is set to be substantially the same as (or slightly shorter than) the axial length of the inner cylindrical body 31 (see FIG. 7).

  As shown in FIGS. 2 to 4, each ground electrode 32 has a plurality of circulation holes H (mesh) through which air passes. The ground electrode 32 is formed into a cylinder, for example, by bending a single metal net made of metal such as stainless steel (SUS304). The wire diameter of the ground electrode 32 can be set in the range of 0.1 to 1.0 mm, and the mesh opening (mesh opening diameter) of the ground electrode 32 can be set in the range of 1 to 5 mm, for example. The aperture ratio of the ground electrode 32 can be set in the range of 50 to 70%, for example. The opening ratio of the ground electrode 32 is the ratio of the flow holes H to the surface area of the ground electrode 32. Further, in the accompanying drawings, a mesh of a part of the ground electrode 32 is illustrated. The surface of the ground electrode 32 is coated with fluorocarbon resin having conductivity.

  As shown in FIGS. 2 to 4, the three ground electrodes 32 include an outer ground electrode 321, a middle ground electrode 322, and an inner ground electrode 323. The outer ground electrode 321, the middle ground electrode 322, and the inner ground electrode 323 are arranged in this order from the outer side to the inner side in the radial direction. The middle ground electrode 322 and the inner ground electrode 323 have seams formed by bending a wire mesh. Further, the outer ground electrode 321 is processed so that no seam appears. Further, in the present specification, the description common to the outer ground electrode 321, the middle ground electrode 322, and the inner ground electrode 323 is simply referred to as “ground electrode 32”.

(Outer ground electrode)
As shown in FIGS. 2, 3, 6 and 7, the outer ground electrode 321 is arranged so as to face the inner peripheral surface of the outer tubular body 30 with a gap therebetween. That is, the outer cylinder body 30 described above is arranged on the same axial center as the inner cylinder body 31 radially outside of the outer ground electrode 321.

  The outer ground electrode 321 is fixed to the outer tubular body 30 via a plurality (eg, six) of spacers S. In the present embodiment, three spacers S are provided at two locations apart from each other in the axial direction of the outer ground electrode 321 (outer cylinder body 30) at substantially equal intervals (120 degree intervals) in the circumferential direction per location. The spacer S is made of a conductive metal material and is formed in a substantially hexagonal column shape extending in the radial direction. The outer cylindrical body 30 is screwed to the outer side of the spacer S in the radial direction, and the outer ground electrode 321 is screwed to the inner side of the spacer S in the radial direction. As a result, the outer cylindrical body 30 and the outer ground electrode 321 are fixed with a gap (spacer S) therebetween. The outer ground electrode 321 is connected to the ground via the spacer S and the outer cylinder body 30. Further, a flow prevention member 37A for preventing the inflow of dust-containing air into the gap is provided at the upstream end in the flow direction of the gap between the outer tubular body 30 and the outer ground electrode 321 (see FIG. 7). ). The tip of the fixing screw 51 for fixing the first to third power feeding heads 421B to 423B and the fourth to fifth power feeding heads 461B to 462B to the outer tubular body 30 and the nut are arranged in the gap. Has been done. The spacer S may be omitted, and the outer ground electrode 321 may be in contact with the outer cylindrical body 30.

(Inner ground electrode)
As shown in FIGS. 2 to 7, the inner ground electrode 323 is arranged radially outside the inner cylindrical body 31 and radially inward with respect to the outer ground electrode 321 with a gap therebetween. The inner ground electrode 323 is fixed to the inner cylindrical body 31 via a plurality (eg, six) of spacers S. In the present embodiment, three spacers S are provided at two locations apart from each other in the axial direction of the inner ground electrode 323 (the inner cylindrical body 31) at substantially equal intervals (120 degree intervals) in the circumferential direction per location. The inner cylindrical body 31 is screwed to the radially inner side of the spacer S, and the inner ground electrode 323 is screwed to the radially outer side of the spacer S. As a result, the inner cylindrical body 31 and the inner ground electrode 323 are fixed with a gap (spacer S) therebetween. The inner ground electrode 323 is connected to the ground via the spacer S, the inner cylinder 31, the connecting member 35, and the outer cylinder 30. A flow prevention member 37B is provided at the upstream end of the gap between the inner cylindrical body 31 and the inner ground electrode 323 to prevent dust-containing air from flowing into the gap (see FIG. 7). Note that, instead of the flow prevention member 37B, the closing portion 35A of the connecting member 35 may close the gap. Further, the spacer S may be omitted, and the inner ground electrode 323 may be in contact with the inner cylindrical body 31. The spacer S is provided at a position where it does not interfere with the ejection port 63 opened in the inner cylindrical body 31.

(Middle ground electrode)
As shown in FIGS. 2 to 4, 6, and 7, the middle ground electrode 322 is arranged so as to divide the gap between the outer ground electrode 321 and the inner ground electrode 323 into two halves in the radial direction. There is. The middle ground electrode 322 is supported by the outer cylinder body 30 and the like via the above-mentioned connecting member 35. The pair of connecting arms 35B of the connecting member 35 are screwed to the pair of receiving portions 32P formed at the front and rear edges of the middle ground electrode 322 (see FIG. 6). As a result, the middle ground electrode 322 is fixed to the outer ground electrode 321 and the inner ground electrode 323 with a gap therebetween. The middle ground electrode 322 is connected to the ground via the connecting member 35 and the outer tubular body 30. It should be noted that the fact that the middle ground electrode 322 bisects the gap between the outer and inner ground electrodes 32A, 32C in the radial direction does not require strictly bisect, and it does not mean that the gap is several millimeters in manufacturing. This means that an error is allowed.

  As shown in FIG. 2, FIG. 3, FIG. 6 and FIG. 7, an outer flow path 38 </ b> A is formed between the outer ground electrode 321 and the middle ground electrode 322 to allow the dust-containing air to flow therethrough. An inner flow path 38B is formed between the inner ground electrode 323 and the middle ground electrode 322 to allow dust-containing air to flow therethrough. As described above, since the middle ground electrode 322 is located at the radial center of the gap between the outer ground electrode 321 and the inner ground electrode 323, the radial length (Y1) of the outer flow path 38A and the inner The length (Y2) in the radial direction of the flow path 38B is set to be substantially the same (see FIG. 7). The outer flow path 38A and the inner flow path 38B are formed in a substantially circular band shape when viewed from the side surface. Since the outer flow passage 38A is located on the outer periphery of the inner flow passage 38B, the cross-sectional area of the outer flow passage 38A is larger than that of the inner flow passage 38B.

<Discharge part>
As shown in FIGS. 3, 4, 6, and 7, the five discharge units 33 (first to fifth discharge units 331 to 335) include five support members 40 (first to fifth support members 401 to 401). 405) and a plurality of discharge electrodes 50. The five supports 40 are arranged in the gap between the ground electrodes 32. The plurality of discharge electrodes 50 are supported by each support 40. In the present specification, the description common to the first to fifth discharging units 331 to 335 will be simply referred to as “discharging unit 33”. Similarly, in the description common to the first to fifth supports 401 to 405, they will be simply referred to as "support 40".

  The five support bodies 40 are formed in a substantially cylindrical shape extending in the left-right direction (the flow direction of the dust-containing air). The five supports 40 are formed to be sufficiently shorter in the axial direction than the ground electrode 32. Each support 40 is made of, for example, a metal material such as stainless steel. Although not shown, the support 40 is formed into a cylindrical shape by stacking two strip-shaped plates, and the discharge electrode 50 is sandwiched between the two strip-shaped plates. It should be noted that the single support 40 may be molded into a cylindrical shape.

  The five supports 40 are arranged in the outer flow path 38A and the inner flow path 38B while supporting the discharge electrode 50. More specifically, the first support 401, the second support 402, and the third support 403 are arranged in the outer flow path 38A. A fourth support body 404 and a fifth support body 405 are arranged in the inner flow path 38B. That is, the number of the support bodies 40 arranged is set to be larger in the outer flow passages 38A than in the inner flow passages 38B.

(First to third supports)
As shown in FIGS. 3, 6 and 7, the first to third support members 401 to 403 are formed in a substantially cylindrical shape having substantially the same diameter. The first to third supports 401 to 403 are arranged in this order in parallel from the upstream side to the downstream side in the flow direction at substantially equal intervals. The first to third supports 401 to 403 are arranged on the same axis as the inner cylinder 31 with a gap between the outer ground electrode 321 and the middle ground electrode 322. The first to third supports 401 to 403 are arranged so as to divide the outer flow path 38A into two equal parts in the radial direction.

  As shown in FIG. 3 and FIG. 6, the first support 401 is fixed to the outer tubular body 30 via two first support insulators 411 and one first power supply insulator 421. The two first support insulators 411 and the one first power feeding insulator 421 are made of a material having electrical insulation such as ceramics, and are provided at substantially equal intervals (120 degree intervals) in the circumferential direction. The three insulators 41A, 42A are arranged at positions displaced in the circumferential direction so as not to interfere with the spacer S described above.

(First support insulator)
Each of the first support insulators 411 has a substantially cylindrical first support protrusion 411A extending in the radial direction, and a flange-shaped first support head 411B formed at the radially outer end of the first support protrusion 411A. And, are included. The first support protrusion 411A radially penetrates the outer cylinder body 30 and the outer ground electrode 321 and has its tip end in contact with the first support 401 arranged in the outer flow path 38A. (The outer cylindrical body 30 and the outer ground electrode 321 are formed with holes through which the first support protrusion 411A can pass.) The first support 401 is screwed to the tip of the first support protrusion 411A. ing. The first support head 411B is located outside the outer tubular body 30.

(1st power insulator)
As shown in FIGS. 3, 6 and 7, the first power feeding insulator 421 has a substantially cylindrical first power feeding protrusion 421A extending in the radial direction and a radially outer end portion of the first power feeding protrusion 421A. And a first power feeding head 421B formed in a flange shape. A through hole for allowing the first power feed screw 431 (outer power feed member) to pass therethrough is formed in the axial center portion of the first power feed insulator 421.

  The first power supply protrusion 421A penetrates the outer cylinder body 30 and the outer ground electrode 321 in the radial direction, and the tip end thereof is in contact with the first support 401 arranged in the outer flow path 38A. (A hole through which the first power feeding protrusion 421A can pass is formed in the outer tubular body 30 and the outer ground electrode 321.) The first power feeding head 421B abuts on the outer peripheral surface of the outer tubular body 30. It is fixed to the outer cylinder body 30 with two fixing screws 51. The first power feeding screw 431 penetrates through the through holes of the first support body 401 and the first power feeding insulator 421 from the radially inner side, and the tip portion thereof is projected from the first power feeding head portion 421B. A first power feeding nut 441 is screwed onto the tip of the first power feeding screw 431 so as to sandwich the power feeding cable 52 connected to the high voltage generation unit 72 (power source (see FIG. 8)).

  As described above, the first support body 401 is fixed to the outer tubular body 30 while being electrically insulated by the two first support insulators 411 and the one first power supply insulator 421. In addition, the first support 401 and the high voltage generation unit 72 are electrically connected by the first power supply screw 431 and the power supply cable 52.

  Although detailed description is omitted, the second to third support bodies 402 to 403 are also similar to the first support body 401 in that two second to third support insulators 412 to 413 and one second to third support body. It is fixed to the outer tubular body 30 via the three power feeding insulators 422 to 423. In addition, in this specification, in the description common to the 1st-3rd support insulator 411-413 (1st-3rd support protrusion 411A-413A, 1st-3rd support head 411B-413B), it is "outside. The support insulator 41 (outer support protrusion 41A, outer support head 41B) "will be referred to. Similarly, in the description common to the first to third power feeding insulators 421 to 423 (the first to third power feeding protrusions 421A to 423A, the first to third power feeding heads 421B to 423B), the description is “outer power feeding insulator. 42 (outer power feeding protrusion 42A, outer power feeding head 42B) ". Further, in the description common to the first to third power feeding screws 431 to 433 and the first to third power feeding nuts 441 to 443, they are referred to as “outer power feeding screw 43” and “outer power feeding nut 44”.

  The first and third power feeding insulators 421 and 423 are arranged on the upper portion of the outer tubular body 30 and are housed in the upper insulator housing box 53U fixed to the upper surface of the outer tubular body 30 (see FIGS. 2 and 7). .. On the other hand, the second power feeding insulator 422 is arranged in the lower portion of the outer tubular body 30 and is housed in the lower insulator housing box 53D fixed to the lower surface of the outer tubular body 30 (see FIG. 7). The upper insulator storage box 53U and the lower insulator storage box 53D are provided with removable lids (not shown).

(4th-5th support)
Next, as shown in FIGS. 4, 6 and 7, the fourth to fifth supports 404 to 405 are formed in a substantially cylindrical shape having substantially the same diameter. The fourth to fifth supports 404 to 405 are formed to have a smaller diameter than the first to third supports 401 to 403. The fourth to fifth supports 404 to 405 are arranged in parallel in this order from the upstream in the flow direction to the downstream. The fourth to fifth supports 404 to 405 are arranged on the same axis as the inner cylinder 31 with a gap between the middle ground electrode 322 and the inner ground electrode 323. The fourth to fifth supports 404 to 405 are arranged so as to bisect the inner channel 38B in the radial direction.

  As shown in FIG. 7, the second to third supports 402 to 403 arranged in the outer flow path 38A and the fourth to fifth supports 404 to 405 arranged in the inner flow path 38B are dust-containing air. Are arranged at the same position in the distribution direction. That is, the fourth to fifth supports 404 to 405 are arranged at positions overlapping the second to third supports 402 to 403 when viewed in the radial direction.

  As shown in FIGS. 4 and 6, the fourth support body 404 is fixed to the middle ground electrode 322 and the like via two fourth support insulators 451 and one fourth power supply insulator 461. The two fourth support insulators 451 and the one fourth power supply insulator 461 are made of an electrically insulating material such as ceramics, and are provided at substantially equal intervals (120 degree intervals) in the circumferential direction. The three insulators 451 and 461 are arranged at positions displaced in the circumferential direction so as not to interfere with the spacer S described above.

(4th support insulator)
Each of the fourth support insulators 451 has a substantially cylindrical fourth support protrusion 451A extending in the radial direction, and a fourth support head 451B formed in a flange shape at the radial outer end of the fourth support protrusion 451A. And, are included. The fourth support protrusion 451A penetrates the middle ground electrode 322 in the radial direction, and the tip thereof is in contact with the fourth support 404 arranged in the inner flow path 38B. The fourth support 404 is screwed to the tip of the fourth support protrusion 451A. The fourth support head 451B is located outside the middle ground electrode 322.

(4th power insulator)
As shown in FIGS. 4, 6 and 7, the fourth power feeding insulator 461 has a substantially cylindrical fourth power feeding protruding portion 461A extending in the radial direction and a radially outer end portion of the fourth power feeding protruding portion 461A. And a fourth power feeding head 461B formed in a flange shape. A through hole for allowing the fourth power feed screw 471 (inner power feed member) to pass therethrough is formed in the axial center portion of the fourth power feed insulator 461.

  The fourth power feeding protrusion 461A is formed to be longer in the radial direction than the outer power feeding protrusion 42A of the outer power feeding insulator 42. The fourth power feeding protrusion 461A radially penetrates the outer cylindrical body 30, the outer ground electrode 321, the second support 402 and the middle ground electrode 322, and the tip end thereof is disposed in the inner flow path 38B. It is in contact with the support 404. The fourth power feeding head 461B is in contact with the outer peripheral surface of the outer tubular body 30 and is fixed to the outer tubular body 30 with two fixing screws 51. The fourth power feeding screw 471 penetrates through the through holes of the fourth support body 404 and the fourth power feeding insulator 461 from the radially inner side, and the tip end thereof is projected from the fourth power feeding head 461B. A fourth power feeding nut 481 is screwed to the tip of the fourth power feeding screw 471 so as to sandwich the power feeding cable 52 connected to the high voltage generating unit 72.

  As described above, the fourth support 404 is fixed to the outer cylinder body 30 and the middle ground electrode 322 while being electrically insulated by the two fourth support insulators 451 and the one fourth power supply insulator 461. ing. Further, the fourth support body 404 and the high voltage generation unit 72 are electrically connected by the fourth power feeding screw 471.

  In addition, although detailed description is omitted, the fifth support 405 also includes the outer cylindrical body 30 and the fifth support 452 and one fifth power supply insulator 462, similarly to the fourth support 404. It is fixed to the middle ground electrode 322. In addition, in this specification, in the description common to the fourth to fifth support insulators 451 to 452 (the fourth to fifth support protrusions 451A to 452A and the fourth to fifth support heads 451B to 452B), "inside" is described. The support insulator 45 (inner support protrusion 45A, inner support head 45B) "will be referred to. Similarly, in the description common to the fourth to fifth power feeding insulators 461 to 462 (the fourth to fifth power feeding protrusions 461A to 462A and the fourth to fifth power feeding heads 461B to 462B), "the inner power feeding insulator is described. 46 (inner power feeding protrusion 46A, inner power feeding head portion 46B) ". Further, in the description common to the fourth to fifth power feeding screws 471 to 472 and the fourth to fifth power feeding nuts 481 to 482, they are referred to as "inner power feeding screw 47" and "inner power feeding nut 48".

  The fourth power feeding insulator 461 is arranged between the first and third power feeding insulators 421 and 423 at the upper part of the outer tubular body 30 and is housed in the upper insulator housing box 53U (see FIGS. 2 and 7). On the other hand, the fifth power feeding insulator 462 is arranged on the lower side of the second power feeding insulator 422 in the lower portion of the outer tubular body 30 in the flow direction, and is stored in the lower insulator storage box 53D (see FIG. 7).

  Note that the pair of connecting arms 35B of the connecting member 35 are arranged at a position that is deviated by approximately 90 degrees with respect to the outer power feeding insulator 42 and the inner power feeding insulator 46 when viewed from the flow direction of the dust-containing air. The connecting arm 35B is formed to have substantially the same width as or slightly wider than the respective feeding protrusions 42A and 46A of the feeding insulators 42 and 46.

  The fixing positions of the various insulators 41, 42, 45, 46 described above are merely examples, and the present invention is not limited to this. The fixed positions of the various insulators 41, 42, 45, 46 can be freely set so that they do not interfere with each other. Further, although the above-described power feeding insulators 42 and 46 are independent for each support body 40, the present invention is not limited to this. For example, three power feeding insulators 421, 423, 461 stored in the upper insulator storage box 53U and two power feeding insulators 422, 462 stored in the lower insulator storage box 53D may be integrally formed.

(Discharge electrode)
The discharge electrode 50 is formed in a brush shape by bundling a plurality of (for example, about 10 to 100) fibrous line electrodes (see FIG. 9). The wire electrode is formed of, for example, a stainless fiber material having a diameter of 5 to 25 μm. As the material of the wire electrode, non-magnetic stainless steel or the like can be used, and for example, austenitic stainless steel (SUS304, SUS316, etc.) having excellent corrosion resistance is preferably used. The discharge electrode 50 (line electrode) is fixed to the support 40 by a processing method such as pressure bonding, adhesion, or flocking.

  As shown in FIG. 3, FIG. 4 and FIG. 7, the plurality of discharge electrodes 50 are extended from the support 40 toward the upstream side and the downstream side in the flow direction. The discharge electrodes 50 are formed in such a length that the discharge electrodes 50 adjacent to each other in the flow direction (axial direction) do not interfere with each other. The plurality of discharge electrodes 50 may be extended from the support body 40 only to the upstream side, or may be extended only from the support body 40 to the downstream side (not shown). The discharge electrode 50 supported by the first support 401 is referred to as a “first discharge electrode 501”, and similarly, the discharge electrode 50 supported by the second to fifth supports 402 to 405. Will be referred to as "second to fifth discharge electrodes 502 to 505", respectively. Further, in the description common to the first to fifth discharge electrodes 501 to 505, they will be simply referred to as "discharge electrodes 50".

  The plurality of discharge electrodes 50 are arranged side by side at substantially equal intervals in the circumferential direction of the support 40. Specifically, the plurality of first discharge electrodes 501 are displaced from the plurality of second discharge electrodes 502 by a half pitch in the circumferential direction. Similarly, the plurality of fourth discharge electrodes 504 are displaced from the plurality of fifth discharge electrodes 505 by a half pitch in the circumferential direction. Note that the plurality of first discharge electrodes 501 and the plurality of third discharge electrodes 503 are arranged in substantially the same phase in the circumferential direction (not displaced). In addition, in one support 40, the plurality of discharge electrodes 50 on the upstream side and the plurality of discharge electrodes 50 on the downstream side may be displaced by a half pitch in the circumferential direction (not shown). Further, the plurality of discharge electrodes 50 may not be displaced in the circumferential direction, and may be arranged in the same phase in the circumferential direction (not shown).

  The discharge electrodes 50 are arranged substantially at the center of the outer flow path 38A in the radial direction and at the center of the inner flow path 38B in the radial direction. The above-mentioned ground electrode 32 is provided with a gap for generating a corona discharge (forming a charging area EA) between each of the discharge electrodes 50. The gap (shortest distance) between the tip of the discharge electrode 50 and the ground electrode 32 is set to a distance (about 10 mm) that can generate an appropriate corona discharge in relation to the applied voltage. In this embodiment, the voltage applied between the discharge electrode 50 and the ground electrode 32 is set in the range of 4 kV or more and 6 kV or less.

<Air jet>
As shown in FIG. 1, the air ejecting portion 34 includes an inner cylindrical body 31, an air supply pipe 60, a regulating valve 61, and an air blow gun 62. As described above, the inner cylindrical body 31 has the peripheral wall formed with the plurality of ejection ports 63 which are the ejection ports of the compressed air toward the ground electrode 32. The air supply pipe 60 is a pipe for introducing compressed air into the inner cylindrical body 31. The adjustment valve 61 is an electromagnetic valve that adjusts the amount of compressed air passing through the air supply pipe 60. The air blow gun 62 is a device that a worker manually blows out compressed air.

(Inner cylinder (spout))
As shown in FIGS. 5 and 7, the inner cylindrical body 31 is a member for supporting the inner ground electrode 323 and also a member that constitutes the air ejection portion 34. The inner cylindrical body 31 is formed in a hollow, substantially cylindrical shape, and a plurality of ejection ports 63 that communicate the inside and the outside are opened in the peripheral wall of the inner cylindrical body 31. The ejection port 63 is a substantially circular hole having a diameter of about several mm. In the present embodiment, six outlets 63 are formed at substantially equal intervals (60 degree intervals) in the circumferential direction per location at four positions that are spaced apart at substantially equal intervals in the axial direction of the inner cylindrical body 31. That is, in the present embodiment, a total of 24 ejection ports 63 are formed in the inner cylindrical body 31.

  The six upstreammost ejection ports 63 are formed at positions corresponding to the upstream side of the upstream end of the first discharge electrode 501 when viewed in the radial direction (direction intersecting with the flow direction of the dust-containing air). .. The six jet nozzles 63 second from the most upstream are between the downstream end of the first discharge electrode 501 and the upstream end of the second discharge electrode 502 (or the fourth discharge electrode 504) when viewed in the radial direction. Is formed at a position corresponding to. When viewed in the radial direction, the six outlets 63, which are the third from the most upstream, have the downstream end of the fourth discharge electrode 504 (or the second discharge electrode 502) and the fifth discharge electrode 505 (or the third discharge electrode 505). It is formed at a position corresponding to the upstream end of the electrode 503). The six most downstream outlets 63 are formed at positions corresponding to the downstream side of the downstream end of the fifth discharge electrode 505 (or the third discharge electrode 503) when viewed in the radial direction. That is, the ejection port 63 is formed at a position corresponding to the downstream side (or the upstream side) of the corona discharge generation position (the formation position of the charging area EA) except for the ejection port 63 formed in the uppermost stream. There is.

(Air supply pipe, adjusting valve)
As shown in FIG. 1, the air supply pipe 60 is branched from the external pipe 4 of the backwash device 25 and extends toward the inner cylindrical body 31. Specifically, the air supply pipe 60 is branched from the external pipe 4 on the downstream side of the regulator 5 in the compressed air passage direction. As shown in FIG. 7, the air supply pipe 60 penetrates the downstream side of the outer cylindrical body 30, and the terminal portion of the air supply pipe 60 is fixed to the downstream connecting member 35 (closure part 35A) via the elbow pipe 60A. Has been done. Thereby, the air supply pipe 60 connects the compressor 3 (external pipe 4) and the inside of the inner cylindrical body 31. The adjusting valve 61 is provided in the air supply pipe 60 near the outer cylinder body 30 (see FIG. 1).

(Air blow gun)
As shown in FIG. 1, the air blow gun 62 is connected to the end of a blow tube 64 branched from the external pipe 4. The blow tube 64 is branched from the external pipe 4 on the downstream side of the regulator 5 in the compressed air passage direction. The blow tube 64 is configured so that it can be appropriately extended.

<Electronics department>
As shown in FIG. 8, the electrical component section 70 includes an electrical component box 71 (see FIG. 1), a high voltage generation section 72 (power source), a charging control section 73, and a monitoring section 74.

  The electrical equipment box 71 is formed in a substantially rectangular parallelepiped shape and is fixed to the side of the outer tubular body 30 (see FIG. 1). The high voltage generator 72, the charge controller 73, and the monitor 74 are housed inside the electrical equipment box 71.

  The high voltage generator 72 applies a high voltage between the discharge electrode 50 and the ground electrode 32. The high voltage generator 72 includes a high voltage transformer 72A and a voltage doubler 72B. The high-voltage transformer 72A boosts the AC voltage of the original power supply 75 (AC 100V). The voltage doubler 72B converts the AC voltage boosted by the high-voltage transformer 72A into a DC voltage and further boosts it to generate a high voltage of minus several kV. The monitoring unit 74 monitors the high voltage applied to the discharge electrode 50. The source power supply 75 is not limited to an AC power supply, and a DC power supply may be used. Further, if a positive high voltage is applied (in the case of the positive charging method), the discharge electrode 50 and the ground electrode 32 must be close to each other, which may cause abnormal discharge. In this respect, in the present embodiment, by adopting the negative charging method of applying a negative high voltage, the risk in the case of the positive charging method is reduced.

  In addition, in the present embodiment, the charging control unit 73 performs ON / OFF control of application of a high voltage to the discharge electrode 50 in conjunction with the ON / OFF signal of the dust collector 1. Therefore, the charging device 10 starts the application of the high voltage in association with the start of the operation of the dust collector 1, and stops the application of the high voltage in conjunction with the stop of the operation of the dust collector 1. Further, a voltage required for the dust removal operation is preset in the charging control unit 73, and the charging control unit 73 controls to open the adjustment valve 61 when the set voltage is reached.

[Dust collection operation]
Next, the dust collecting operation of the dust collector 1 will be described with reference to FIGS. 1, 3, 7, and 9. FIG. 9 is a cross-sectional view for explaining the dust collecting action of the dust collecting device 1 and the dust removing action of the charging device 10.

  First, the operator performs a predetermined operation to activate the dust collector 1 (in a preparation state for starting operation). In association with the activation (ON signal) of the dust collector 1, the charging control unit 73 controls the high voltage generation unit 72 to generate a high voltage. The high voltage is applied to the first to fifth discharge electrodes 501 to 505 via the power supply screws 43 and 47 and the first to fifth supports 401 to 405 (see FIGS. 3 and 7). Then, corona discharge occurs between the first to third discharge electrodes 501 to 503 and the outer ground electrode 321, and between the first to third discharge electrodes 501 to 503 and the middle ground electrode 322. As a result, a plurality of substantially conical charging areas EA are formed in the outer flow path 38A (see FIG. 7). Similarly, corona discharge is generated between the fourth to fifth discharge electrodes 504 to 505 and the inner ground electrode 322, and between the fourth to fifth discharge electrodes 504 to 505 and the inner ground electrode 323. Occur. As a result, a plurality of substantially conical charging areas EA are formed in the inner flow path 38B (see FIG. 7).

  The control unit 6 (see FIG. 8) of the dust collector 1 rotates the exhaust fan of the collector 20. Then, an air flow is formed from the suction port (not shown) of the intake duct 2 toward the exhaust port 24 (see FIG. 1), so that dust-containing air passes from the outside through the intake duct 2 and the charging device 10 (outer cylinder). It is taken inside the body 30). The dust-containing air flows into the outer flow passage 38A and the inner flow passage 38B, and flows from upstream to downstream along the respective flow passages 38A and 38B (see the thick arrow in FIG. 7). The conical portion 36 has a function of guiding the dust-containing air to the inner flow passage 38B.

  As shown in FIG. 9, the dust-containing air flows through the gap between the discharge electrode 50 and the ground electrode 32. The dust in the dust-containing air is charged in the process of passing through the plurality of charging areas EA formed in the gaps (each of the flow paths 38A and 38B) between the discharge electrode 50 and the ground electrode 32, attracted to each other, and aggregated. Coarsening (coarsening particle size to 20 times or more). Here, as described above, since the plurality of discharge electrodes 50 on the upstream side and the plurality of discharge electrodes 50 on the downstream side are displaced from each other by the half pitch in the circumferential direction, the charging area EA on the upstream side and the charging on the downstream side are charged. Areas EA are formed alternately in the circumferential direction. As a result, an area that cannot be formed in the charging area EA by the upstream discharge electrode 50 can be supplemented by the charging area EA formed around the downstream discharge electrode 50. As a result, almost all of the dust-containing air passes through the charging area EA, so that almost all of the dust contained in the dust-containing air can be charged.

  The dust-containing air including the coarsened dust flows out of the outer flow path 38A and the inner flow path 38B and enters the dirty room R1 (see FIG. 1) of the collection device 20. Most of the coarse dust passes through the outer flow path 38A and the inner flow passage 38B to flow into the dirty room R1. However, a part of the coarse dust is supplied to the ground electrodes 321 to 323 and the ground electrodes 321 to 323. It adheres to the discharge part 33 and the like.

  The dust-containing air taken into the dirty room R1 is filtered while passing through the filters 23 to become clean air. The dust is mainly collected on the surface side of the filter 23 (nonwoven fabric) (see FIG. 9). The clean air is exhausted into the clean room R2 through the top opening of the filter 23, passes through the clean room R2, and is exhausted to the outside through the exhaust port 24 (see FIG. 1).

  As described above, by charging and coarsening the dust by the charging device 10, it is possible to prevent the dust from entering deep inside the filter 23 (nonwoven fabric), and to collect the dust on the surface side of the non-woven fabric. Thereby, the clogging of the filter 23 can be suppressed. The dust that is not collected by the filter 23 and falls is accumulated in the bucket (see FIG. 1).

[Backwash operation of filter]
Next, the backwashing operation of the filter 23 will be described with reference to FIG.

  The control unit 6 executes the backwash operation when it is determined that the detected value of the differential pressure gauge (not shown) that detects the differential pressure between the dirty room R1 and the clean room R2 exceeds the threshold value. Further, the control unit 6 sequentially performs the backwash operation on the two filters 23 arranged in three rows one by one. The execution timing of the backwash operation is not limited to the above. For example, the backwash operation may be performed when the dust collector 1 is stopped, or the backwash operation may be performed at a timing set in advance by a timer. Good. The threshold value of the differential pressure and the time (interval) of the timer are set by the operator in advance.

  The backwash operation is performed while continuing suction of the dust-containing air without stopping the exhaust fan. In addition, the backwash operation may be performed in a state in which the rotation speed of the exhaust fan is lower than that in the normal time (during the dust collection operation). As described above, the backwash operation is preferably performed in a state in which the dust-containing air is continuously sucked without stopping the exhaust fan, but the invention is not limited to this, and may be performed in a state in which the exhaust fan is stopped.

  With the dust collector 1 activated, the backwash valve 28 is controlled by the control unit 6 to be closed. Then, the compressed air is stored in the header tank 26 connected to the compressor 3. In the present embodiment, the pressure of the compressed air by the compressor 3 is set to 1.0 MPa, for example, and the pressure of the compressed air supplied to the header tank 26 is set to 0 by the regulator 5 provided in the external pipe 4. It is set to 0.4 to 0.7 MPa.

  When the control unit 6 determines that the detection value of the differential pressure gauge exceeds the threshold value, the control unit 6 performs control to open the backwash valve 28. Then, the compressed air stored in the header tank 26 passes through the blow tube 27 and is ejected from the two outlets 27 </ b> A toward the top openings of the two filters 23.

  The compressed air flows backward from the radial center of the filter 23 toward the outside, and removes the dust collected in the filter 23 (nonwoven fabric). Since the dust is collected on the surface side of the nonwoven fabric, it is easily wiped off by the backflow of compressed air. The dust that has been thrown off falls into a bucket provided in the lower part of the collection device 20, and the accumulated dust is appropriately discarded.

  The control unit 6 performs control to close the backwash valve 28 after a lapse of a predetermined time (after several tens ms to several hundred ms) from the start of injection of compressed air (opening of the backwash valve 28). As a result, compressed air is stored again in the header tank 26.

[Dust removal operation for ground electrodes, etc.]
Next, the dust removing operation of the ground electrode 32 and the like will be described with reference to FIGS.

  As described above, when the dust collecting operation is continued, some charged dust (coarse dust) is accumulated on each ground electrode 32 and each discharge part 33 (each support 40 and each discharge electrode 50). Adhere to. The charged dust easily adheres to the ground electrode 32 on the downstream side of the discharge section 33. When corona discharge is performed by constant current control, if dust adheres to the ground electrode 32 or the discharge electrode 50, it becomes difficult for a current to flow between the discharge electrode 50 and the ground electrode 32, and thus the applied voltage increases. .. For example, if the applied voltage during normal operation is 5 kV, it may be necessary to apply a voltage of about 6 kV as dust adheres to the ground electrode 32 and the discharge electrode 50. Therefore, when the charging control unit 73 determines that the voltage monitored by the monitoring unit 74 exceeds the preset threshold value, the charging control unit 73 performs the dust removing operation of the ground electrode 32 and the like. The timing of performing the dust removal operation is not limited to the above, and for example, the dust removal operation may be performed when the dust collector 1 is stopped, or the dust removal operation may be performed at a timing set in advance by a timer. The threshold value and the time (interval) of the timer are set by the operator in advance. Further, the dust removing operation may be performed without stopping the exhaust fan, or may be performed with the exhaust fan stopped, similarly to the above-described backwashing operation of the filter 23.

  When the dust collector 1 is activated, the adjustment valve 61 is opened by being controlled by the charging controller 73. The compressed air whose pressure is adjusted (0.4 to 0.7 MPa) by the regulator 5 is supplied to the inner cylinder 31 through the air supply pipe 60. The dust removal operation of the ground electrode 32 and the like uses compressed air having the same pressure as the backwash operation of the filter 23.

  As shown in FIGS. 7 and 9, the compressed air supplied to the inner tubular body 31 is blown out from the plurality of ejection ports 63 toward the radially outer side (the direction intersecting the flow direction of the dust-containing air). That is, the compressed air is jetted from a direction (normal direction) that is substantially perpendicular to the surface of the ground electrode 32. The compressed air blown out from the ejection port 63 is blown toward the position corresponding to the downstream side of the discharge electrode 50 in the ground electrode 32. First, the compressed air blown out from the ejection port 63 blows off the dust adhering to the inner ground electrode 323 while passing through the circulation hole H of the inner ground electrode 323. Subsequently, the compressed air that has passed through the inner ground electrode 323 blows off the dust attached to the inner ground electrode 322 while passing through the flow hole H of the inner ground electrode 322. Next, the compressed air that has passed through the middle-side ground electrode 322 blows off the dust adhering to the outer-ground electrode 321 while passing through the flow holes H of the outer-ground electrode 321. The compressed air that has passed through the outer ground electrode 321 blows off the dust attached to the inner peripheral surface of the outer tubular body 30.

  More specifically, the compressed air blown from the most upstream jet port 63 is blown toward the upstream side of the upstream end of the first discharge electrode 501. The compressed air blown from the second outlet 63 from the most upstream is located downstream of the downstream end of the first discharge electrode 501 (upstream of the upstream end of the second or fourth discharge electrode 502, 504). It is blown towards. The compressed air blown from the third outlet 63 from the most upstream is downstream of the downstream end of the fourth discharge electrode 504 (second discharge electrode 502) (the third or fifth discharge electrode 503, 505). It is sprayed toward the upstream side of the upstream end). The compressed air blown out from the most downstream jet port 63 is blown toward the downstream side of the downstream end of the fifth discharge electrode 505 (third discharge electrode 503). To be precise, since the compressed air is blown out while being diffused from the ejection port 63, it is also blown to areas other than the above-mentioned blowing area (the discharge electrode 50, the support 40, etc.). For this reason, for example, the dust adhering to the discharge electrode 50 or the support 40 can also be blown off by the compressed air.

  As described above, the air ejecting unit 34 blows the compressed air onto the ground electrode 32 from the direction intersecting the flow direction to remove the dust attached to the ground electrode 32. Further, since each ground electrode 32 has a plurality of through holes H, compressed air can be blown to the three ground electrodes 32 arranged in the radial direction. The charging control unit 73 performs control to close the adjustment valve 61 after a predetermined time period (about 5 seconds has elapsed) from the start of injection of compressed air (opening of the adjustment valve 61). Further, the injection time of compressed air (opening time of the adjusting valve 61) is varied according to the degree of contamination of the ground electrode 32 (ratio of increase in voltage applied between the discharge electrode 50 and the ground electrode 32). May be. Specifically, since the voltage applied between the discharge electrode 50 and the ground electrode 32 rises as the degree of contamination of the ground electrode 32 increases, the valve opening time of the adjustment valve 61 is lengthened accordingly. May be set as follows.

  By the way, most of the dust adhering to the ground electrode 32 can be removed by the above-described dust removing operation. However, if the dust collecting operation is continued for a long period of time, the dust may be accumulated in a place where the action of compressed air is difficult. is there. Therefore, the operator blows off the dust accumulated on the ground electrode 32 using the air blow gun 62. When the air blow gun 62 is used, the dust collector 1 (suction of dust-containing air) is stopped.

  First, the operator opens the inspection port 2A of the intake duct 2 and inserts the air blow gun 62 into the intake duct 2 through the inspection port 2A (see FIG. 1). Next, the operator operates the air blow gun 62 to inject the compressed air toward the charging device 10 and blow off the dust accumulated on the ground electrode 32. After the work using the air blow gun 62 is completed, the worker closes the inspection port 2A. Further, an inspection port (not shown) that can be opened and closed is provided on the outer cylinder body 30, and the operator opens the inspection port and operates the air blow gun 62 to cause the dust-containing air to flow to the charging device 10. It is also possible to inject compressed air from a direction intersecting with and blow off the dust accumulated on the ground electrode 32. In this case, inspection ports may be provided at a plurality of locations in the flow direction and the radial direction of the outer cylinder body 30.

  The charging device 10 according to the present embodiment described above has a configuration in which the compressed air is blown out in the direction in which the air ejection portion 34 intersects the flow direction. In addition, the ground electrode 32 was formed with a plurality of circulation holes H through which the compressed air blown from the air ejection portion 34 passes. According to this configuration, the blown compressed air can blow off the dust (particles) attached to the ground electrode 32 while passing through the circulation hole H of the ground electrode 32. Thus, the dust attached to the ground electrode 32 can be properly removed. In addition, it is possible to prevent troubles such as dust removed from the ground electrode 32 flowing to the downstream side and clogging the filter 23. As a result, stable performance of the ground electrode 32, the filter 23, etc. can be maintained for a long period of time.

  Further, according to the charging device 10 according to the present embodiment, since both end surfaces of the inner cylindrical body 31 are closed by the connecting members 35 and the like (see FIG. 7), the inner cylindrical body 31 that does not become the charging area EA is introduced. The inflow of dust-containing air can be prevented.

  Further, according to the charging device 10 according to the present embodiment, the compressed air supplied from the air supply pipe 60 to the inner tubular body 31 is radially outward from the ejection port 63 of the inner tubular body 31 (a direction intersecting the flow direction). ) Can be spouted. As a result, dust attached to the ground electrode 32 can be blown outward in the radial direction.

  Further, according to the charging device 10 according to the present embodiment, it is possible to blow compressed air to a portion of the ground electrode 32 where dust is likely to adhere (such as the downstream side of the charging area EA). As a result, the dust on the ground electrode 32 can be removed efficiently. Further, it is possible to prevent the compressed air from being directly blown to the discharge electrode 50. As a result, it is possible to prevent the discharge electrode 50 from being bent or bent by blowing compressed air.

  Further, according to the charging device 10 according to the present embodiment, since a plurality of charging areas EA can be formed in the two flow paths of the outer flow path 38A and the inner flow path 38B, a large amount of dust-containing air can be circulated. Even if it does, dust can be appropriately charged. Further, since the middle ground electrode 322 divides one flow path into two equal parts, the outer flow path 38A and the inner flow path 38B are formed to have the same width in the radial direction. According to this configuration, the discharge electrodes 50 having the same charging performance (for example, the same length, the same thickness, etc.) can be arranged in the two channels, the outer channel 38A and the inner channel 38B. Thereby, one kind of discharge electrode 50 can be adopted, and the manufacturing cost can be reduced as compared with the case where two or more different kinds of discharge electrodes 50 and the like are adopted. Further, since it is one type of discharge electrode 50, one high voltage generation unit 72 can be shared by a plurality of discharge electrodes 50, which also leads to a reduction in manufacturing cost. It should be noted that it does not mean that the use of two or more different types of discharge electrodes 50 is prevented.

  In addition, in the charging device 10 according to the present embodiment, the outer flow path 38A is located radially outside the inner flow path 38B, so that the cross-sectional area of the outer flow path 38A is inside when viewed from the flow direction. It is configured to be larger than the cross-sectional area of the flow path 38B. Therefore, the flow rate of the dust-containing air is larger in the outer flow passage 38A than in the inner flow passage 38B. Further, a larger number of supports 40 (discharging section 33) are arranged in the outer flow passage 38A than in the inner flow passage 38B. According to this configuration, more discharge electrodes 50 can be arranged in the outer flow passage 38A than in the inner flow passage 38B, and more charging areas EA can be formed in the outer flow passage 38A than in the inner flow passage 38B. You can As a result, the dust can be appropriately charged in the outer flow path 38A through which a large amount of dust-containing air flows.

  Further, in the charging device 10 according to the present exemplary embodiment, the second support body 402 and the fourth support body 404 arranged in the radial direction are arranged at the same position in the flow direction. Similarly, the third support 403 and the fifth support 405 arranged in the radial direction were arranged at the same position in the flow direction. According to this configuration, for example, at a position displaced from the support 40 in the flow direction, compressed air can be blown to the plurality of radially arranged ground electrodes 32 at the same position in the flow direction. In addition, by disposing the plurality of support bodies 40 arranged in the radial direction at the same position in the distribution direction, a space in which the support bodies 40 are arranged, that is, the distribution of the ground electrode 32, as compared with the case where the support bodies 40 are displaced in the distribution direction. The length in the direction can be shortened.

  Further, according to the charging device 10 of the present embodiment, even if the second support body 402 and the fourth support body 404 are arranged at the same position in the distribution direction in the radial direction, the inner power supply insulator 46 and the inner side. Power can be supplied to the fourth support 404 by the power supply screw 47. Similarly, even if the third support body 403 and the fifth support body 405 are arranged side by side in the radial direction at the same position in the flow direction, power can be supplied to the fifth support body 405. Further, since power can be supplied to the supports 401 to 405 arranged on the outer side and the inner side in the radial direction, corona discharge is generated from the discharge electrodes 501 to 505 supported by the support 401 to 405. Therefore, the charging area EA can be formed by the two flow paths 38A and 38B.

  Further, according to the charging device 10 according to the present embodiment, since the fibrous line electrode is used as the discharge electrode 50, the corona discharge can be generated with a lower applied voltage as compared with the case where the thick electrode is used. You can As a result, it is possible to suppress the generation of sparks and also suppress the generation of ozone due to the ionization of air. Further, since a plurality of line electrodes are used for the discharge electrode 50, even if some of the line electrodes are worn, corona discharge can be continuously generated in the remaining line electrodes.

  Further, according to the charging device 10 according to the present embodiment, by coating the ground electrode 32 with a fluororesin having non-adhesiveness, low friction and conductivity, dust of the dust can be maintained while maintaining the function as the ground electrode 32. Adhesion can be suppressed. Further, it is possible to easily remove the dust attached to the ground electrode 32 (coating). Further, by setting the applied voltage to 4 to 6 kV, it is possible to suppress damage / deterioration of the coating of the ground electrode 32.

  In the dust collector 1 according to the present embodiment, the air ejecting unit 34 is configured to remove the dust attached to the ground electrode 32 by the compressed air supplied from the compressor 3. According to this configuration, since the backwash device 25 and the air jetting unit 34 share one compressor 3, it is possible to share a part of the external pipe 4 extending from the compressor 3, the regulator 5, and the like. As a result, the structure of the compressed air supply system can be simplified and the manufacturing cost can be reduced.

  In addition, in the charging device 10 according to the present embodiment, the three ground electrodes 32 have the same aperture ratio, but the present invention is not limited to this. In the charging device 10 according to the modified example, for example, the aperture ratio of the ground electrode 32 may be set to be larger than that of the ground electrode 32 arranged radially outward (not shown). That is, the aperture ratio of the middle ground electrode 322 may be set larger than the aperture ratio of the inner ground electrode 323, and the aperture ratio of the outer ground electrode 321 may be set larger than the aperture ratio of the middle ground electrode 322. According to the charging device 10 according to the modified example of the present embodiment, the aperture ratio of the ground electrode 32 arranged on the radially outer side is set to be larger than the aperture ratio of the ground electrode 32 arranged on the radially inner side. Therefore, it is possible to increase the air volume (circulation volume) of the compressed air passing through the ground electrode 32 arranged on the radially outer side. Thereby, the air volume of the compressed air passing through the ground electrode 32 on the radially inner side and the air volume of the compressed air passing through the ground electrode 32 on the radially outer side can be made substantially uniform. That is, the dust removal effect of the compressed air can be applied to the three ground electrodes 32 arranged in the radial direction substantially uniformly.

  In addition, in the charging device 10 according to the present exemplary embodiment, each connecting member 35 (a pair of connecting arms 35B) is extended in the front-rear direction, and the outer power feeding insulator 42 and the inner power feeding insulator 46 are provided in the vertical direction. The present invention is not limited to this. As a charging device 10 according to another modification, the pair of connecting members 35, the outer power feeding insulator 42, and the inner power feeding insulator 46 may be provided at positions overlapping with each other when viewed from the flow direction of the dust-containing air (not shown). No). In other words, the connecting arm 35B of the connecting member 35 may be arranged so as to cover the outer power feeding insulator 42 and the inner power feeding insulator 46. In the charging device 10 according to another modified example of the present embodiment, the connecting member 35 is provided on the upstream side of the outer power feeding insulator 42 and the inner power feeding insulator 46 in the flow direction, and is viewed from the flow direction of the dust-containing air. 35 and each of the power supply insulators 42 and 46 were arranged so as to have the same phase in the circumferential direction. According to this configuration, a part of the dust contained in the dust-containing air collides with the connecting member 35 and is less likely to collide with the power supply insulators 42 and 46 hidden in the shadow of the connecting member 35. As a result, the amount of dust adhering to the surfaces of the power supply insulators 42 and 46 can be reduced, and the occurrence of creeping leak can be suppressed. The provision of the connecting member 35 at the position where it overlaps with each of the power feeding insulators 42 and 46 does not require that they completely overlap with each other, but means that some deviation is allowed.

  In addition, in the charging device 10 according to the present embodiment (including modified examples; the same applies hereinafter), the ground electrode 32 is formed in a substantially cylindrical shape, but the present invention is not limited to this. For example, the ground electrode 32 may be formed in a rectangular tube shape or a flat plate shape. That is, the ground electrode 32 may have any shape as long as it is provided with a gap for generating a corona discharge between the ground electrode 32 and the discharge electrode 50.

  Further, in the charging device 10 according to the present embodiment, the three ground electrodes 32 are provided, but the present invention is not limited to this. For example, when the amount (concentration) of dust in the dust-containing air is small, the middle ground electrode 322 is omitted, the outer ground electrode 321 and the inner ground electrode 323 are provided, and the space between these ground electrodes 321 and 323 is reduced. Alternatively, only one flow path may be configured (not shown). Alternatively, for example, four (or more) ground electrodes 32 may be provided to form three (or more) flow paths (not shown). That is, one or more ground electrodes 32 may be provided.

  Further, in the charging device 10 according to the present embodiment, the five discharge parts 33 (support 40 and discharge electrode 50) are provided, but the present invention is not limited to this, and one or more discharge parts 33 may be provided. Good.

  Further, in the charging device 10 according to the present exemplary embodiment, the three discharge parts 33 (supports 40) are arranged in the outer flow path 38A, and the two discharge parts 33 (supports 40) are arranged in the inner flow path 38B. However, the present invention is not limited to this. For example, the number of discharge parts 33 (support 40) may be increased or decreased according to the amount of dust in the dust-containing air. Further, the number of the discharge parts 33 (support 40) arranged may be the same in the outer flow passage 38A and the inner flow passage 38B, or the inner flow passage 38B may be larger in number than the outer flow passage 38A. May be set to.

  Further, in the charging device 10 according to the present embodiment, the ejection port 63 is mainly formed at a position avoiding the formation position of the charging area EA, but the present invention is not limited to this. The ejection port 63 may be formed at a position slightly overlapping the charging area EA (the discharge electrode 50). Further, a nozzle, a deflection plate, or the like for changing the direction of the compressed air blown from the ejection port 63 may be provided between the inner cylindrical body 31 and the inner ground electrode 323 (not shown).

  Further, in the charging device 10 according to the present embodiment, the 24 ejection ports 63 are arranged side by side in the axial direction and the circumferential direction of the inner cylindrical body 31, but the present invention is not limited to this. The number of the ejection ports 63 can be appropriately changed according to the amount of dust in the dust-containing air. Further, the plurality of ejection ports 63 may be arranged in any manner, and may be arranged in a staggered pattern, for example. The shape of the ejection port 63 is not limited to the circular shape, and may be, for example, an elliptical shape or a polygonal shape (not shown).

  Further, in the charging device 10 according to the present embodiment, the 24 ejection ports 63 are all formed to have substantially the same size, but the present invention is not limited to this. For example, the ejection port 63 may be formed so as to gradually increase in size with increasing distance from the connecting portion (elbow pipe 60A) of the air supply pipe 60 (not shown).

  Further, in the charging device 10 according to the present exemplary embodiment, the same high voltage is applied to the five discharge parts 33, but the present invention is not limited to this. For example, a sensor (particle counter or the like) that measures the number of dust (particles) in the dust-containing air is provided on the upstream side of the charging device 10 (intake duct 2 or the like), and the charging control unit 73 displays the output result of the sensor. On the basis of this, a control may be performed so that a high voltage is applied to the discharge unit 33 selected from the plurality of discharge units 33.

  Further, in the charging device 10 according to the present embodiment, the corona discharge is performed by the constant current control, but the present invention is not limited to this, and the constant voltage control may be performed. In this case, the monitoring unit 74 monitors the applied current.

  In addition, the description of the above embodiment shows one mode of the charging device and the dust collecting device according to the present invention, and the technical scope of the present invention is not limited to the above embodiment.

  INDUSTRIAL APPLICABILITY The technique of the present invention can be used for a charging device that charges fine particles generated from a processing machine such as metal or resin. Further, it can be used for a dust collector that collects charged fine particles.

1 Dust collector 3 Compressor (compressed air source)
10 Charging Device 20 Collection Device 23 Filter 25 Back Washing Device 30 Outer Cylinder Body 31 Inner Cylinder Body 32 Ground Electrode 34 Air Ejection Section 35 Connecting Member 38A Outer Flow Path 38B Inner Flow Path 40 Support Body 42 Outer Power Supply Insulator 43 Outer Power Supply Screw (Outer power feeding member)
46 inner feeding insulator 47 inner feeding screw (inner feeding member)
50 Electrode for Discharge 60 Air Supply Pipe 61 Control Valve 63 Jet Port 72 High Voltage Generation Unit (Power Supply)
321 outer ground electrode 322 middle ground electrode 323 inner ground electrode H through hole

Claims (13)

A charging device for charging dust contained in dust-containing air by corona discharge while circulating dust-containing air,
A plurality of discharge electrodes supported by a support,
A ground electrode provided with a gap for generating a corona discharge between each of the discharge electrodes,
An air ejecting unit that blows compressed air onto the ground electrode from a direction intersecting the flow direction of the dust-containing air that flows through the gap between the discharge electrode and the ground electrode to blow off dust adhering to the ground electrode. ,,
The grounding electrode is formed with a plurality of flow holes through which compressed air blown from the air jetting portion passes. Further comprising an inner cylinder formed in a cylindrical shape with both end surfaces in the flow direction of the dust-containing air closed.
The ground electrode is formed in a tubular shape extending in the flow direction of the dust-containing air, and a plurality of the ground electrodes are provided on the same axial center as the inner tubular body with a gap therebetween on the radial outer side of the inner tubular body.
The charging device according to claim 1, wherein the support body is formed in a cylindrical shape extending in a flow direction of the dust-containing air and is arranged in a gap between the ground electrodes. The air ejector is
A plurality of ejection ports serving as blowout ports of compressed air toward the ground electrode, the inner cylinder having a peripheral wall formed;
An air supply pipe for guiding compressed air into the inner cylindrical body,
The charging device according to claim 2, further comprising a regulating valve that regulates an amount of compressed air passing through the air supply pipe.   The charged air according to claim 3, wherein the compressed air blown out from the ejection port is blown toward a position corresponding to a downstream side of the ground electrode in the flow direction of the dust-containing air with respect to the discharge electrode. apparatus.   The charging device according to claim 2, wherein the opening ratio of the ground electrode is set to be larger as the ground electrode is arranged more radially outward. The plurality of ground electrodes,
An outer ground electrode,
An inner ground electrode arranged radially outside of the inner cylindrical body, and radially inside of the outer ground electrode with a gap therebetween.
A middle ground electrode arranged to divide the gap between the outer ground electrode and the inner ground electrode into two halves in the radial direction,
An outer flow path for circulating dust-containing air is formed between the outer ground electrode and the middle ground electrode,
Between the inner ground electrode and the middle ground electrode, an inner flow path for circulating dust-containing air is formed,
The charging device according to claim 2, wherein the support body that supports the discharge electrode is disposed in the outer flow path and the inner flow path.   The charging device according to claim 6, wherein the number of the support bodies arranged is set so that the number of the outer channels is greater than that of the inner channels.   8. The support body arranged in the outer flow path and the support body arranged in the inner flow path are arranged at the same position in the flow direction of the dust-containing air. The charging device according to 1. An outer cylinder body which is formed in a cylindrical shape with both end surfaces of the dust-containing air flowing direction open, and which is arranged on the same axis as the inner cylinder body radially outside of the outer ground electrode,
An outer power feeding insulator formed of an insulator, which penetrates the outer cylindrical body and the outer ground electrode in the radial direction, and has a tip end thereof in contact with the support body arranged in the outer flow path,
An outer power feeding member that radially penetrates the inside of the outer power feeding insulator and electrically connects the support and the power source arranged in the outer flow path,
The outer cylinder body, the outer ground electrode, the support body arranged in the outer flow path, and the middle ground electrode formed of an insulator are radially penetrated, and a tip portion thereof is arranged in the inner flow path. An inner power feeding insulator to be brought into contact with the supported support,
An inner power feeding member that radially penetrates through the inner power feeding insulator and electrically connects the support disposed in the inner flow path to the power source, Item 8. The charging device according to item 8. Further comprising a connecting member that is erected at the upstream end of the outer cylinder and the inner cylinder in the flow direction of the dust-containing air,
The charging device according to claim 9, wherein the connecting member, the outer power feeding insulator, and the inner power feeding insulator are provided at positions overlapping with each other when viewed in a direction in which dust-containing air flows.   The charging device according to claim 1, wherein the discharge electrode is formed by bundling a plurality of fibrous line electrodes. The voltage applied between the discharge electrode and the ground electrode is 4 kV or more and 6 kV or less,
The charging device according to claim 1, wherein the surface of the ground electrode is coated with a conductive fluororesin. A charging device according to any one of claims 1 to 12,
A collection device that is provided on the downstream side of the charging device in the flow direction of dust-containing air, and collects the dust charged by the charging device by a filter,
A backwashing device for removing dust collected by the filter by blowing compressed air supplied from a compressed air source toward the filter,
The dust ejecting device is characterized in that the air ejecting unit blows off dust adhering to the ground electrode by compressed air supplied from the compressed air source.

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