JP2019115893A - Charging device and dust collector - Google Patents

Abstract

To provide a charging device etc., which allows charging efficiency of a floating particle to be improved even while suppressing concentration of ozone which is generated.SOLUTION: A charging part 10 includes a plurality of planar counter electrodes 120 which are arranged in a direction of intersecting a ventilation direction such that each surface runs along the ventilation direction and a plurality of linear high-voltage electrodes 110 respectively provided between the plurality of counter electrodes 120. Therein, the plurality of counter electrodes 120 are constituted such that one side of at least one set of adjacent counter electrodes 120 is a first counter electrode 120A having a first electrode area, the other side is a second counter electrode 120B having a second electrode area which is set smaller than the first electrode area by an opening part 130 and electrifies floating fine particles which float on an air current ventilating between the plurality of counter electrodes 120 and the plurality of high-voltage electrodes 110.SELECTED DRAWING: Figure 1

Description

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

BACKGROUND ART An air cleaner, an air conditioner, and the like are provided with a dust collector that charges floating particles using discharge.
Such a dust collecting apparatus includes a charging unit that charges floating particles by discharge and a dust collection unit that collects charged floating particles. In the charging unit, a high voltage of several kilovolts is applied between the high voltage (discharge) electrode and the counter (ground) electrode to generate a discharge. When the discharge current flowing between the high voltage electrode and the counter electrode is increased to obtain high dust collection efficiency, ozone (O ₃ ) is likely to be generated along with the discharge. Since ozone has a unique odor, the ozone concentration needs to be below the environmental standard value (50 ppb) when released indoors.

  In Patent Document 1, a discharge line disposed in a direction substantially perpendicular to the direction of the air flow and a shape that transmits the air flow are disposed at positions where the charge space between the discharge lines is a uniform charge space of electric field strength. An electrostatic precipitator is described which comprises: an ionizing section having a ground electrode, and a dust collecting section disposed downstream of the ionizing section in the air flow.

  In Patent Document 2, an emitter electrode having a support frame which defines a hollow penetrating portion, and a connecting member which is detachably provided in an outer frame of the support frame and which intersects the penetrating portion and to which a plurality of rod-like electrodes are connected , And a collector electrode having a metal plate electrode which is detachably disposed within the outer frame of the support frame and is installed so as to face the rod-like electrode and which defines a plurality of holes so as to form an ion wind of ambient air. A dust collector is described which comprises:

  In Patent Document 3, a discharge electrode and a counter electrode facing the discharge electrode are configured by a charging unit that generates a corona discharge to charge dust in the air, and the discharge electrode has a plate shape. An electrostatic precipitating charging device is described which is arranged with a gap between the electrodes and to which a voltage is applied according to the distance of the gap.

Japanese Patent Laid-Open No. 6-182255 International Publication No. 2011/034326 Unexamined-Japanese-Patent No. 2010-22999

By the way, when the dust collection device is operated continuously for a long time, ozone is used so as not to feel a pungent odor, discomfort, or pain in the nose or throat while maintaining high collection efficiency. It is necessary to further suppress the occurrence of For this reason, the charging unit of the dust collection apparatus is required to improve the charging (charging) efficiency of the floating particles without increasing the discharge current.
An object of the present invention is to provide a charging device or the like in which the charging efficiency of floating particles is improved while suppressing the concentration of generated ozone.

For this purpose, the charging device to which the present invention is applied includes a plurality of plate-like counter electrodes arranged in a direction intersecting with the ventilation direction so that each surface is along the ventilation direction. Further, the charging device includes linear high-voltage electrodes provided between the plurality of counter electrodes. The plurality of counter electrodes are set such that one of at least one pair of adjacent counter electrodes is a first counter electrode having a first electrode area, and the other is smaller than the first electrode area by an opening. A second counter electrode having a second electrode area, which charges floating particles in an air flow that ventilates between a plurality of the counter electrodes and a plurality of the high-voltage electrodes.
In such a charging device, the second counter electrode may be characterized in that the opening is constituted by a through hole.

The second counter electrode may be characterized in that the opening degree, which is the area of the through hole per unit area, is higher on the downwind side than on the upwind side.
By doing this, the dust collection efficiency can be further improved.

Furthermore, when the planar shape of the through hole at the opening is a circle, the second counter electrode has a diameter of 2.5% or more and 60% or less of the width of the second counter electrode in the ventilation direction. The ratio of the area occupied by the through hole of the opening to the area of the second counter electrode may be 10% or more and 50% or less.
By doing this, the dust collection efficiency can be improved.

The second counter electrode may be characterized in that the center of gravity of the through hole at the opening is on the leeward side of the high-voltage electrode.
By doing this, it is suppressed that the electric field strength in the vicinity of the applied high voltage electrode is reduced.

  For this purpose, the charging device to which the present invention is applied includes a plurality of plate-like counter electrodes arranged in a direction intersecting with the ventilation direction so that each surface is along the ventilation direction. Further, the charging device includes linear high-voltage electrodes provided between the plurality of counter electrodes. Further, in the plurality of counter electrodes, at least one of a pair of adjacent counter electrodes is a first counter electrode having a first electrode area, and the other has a width in the ventilation direction more than the first counter electrode. A second counter electrode having a narrowly set second electrode area, which charges floating particles in an air flow that ventilates between a plurality of the counter electrodes and a plurality of the high-voltage electrodes.

The second counter electrode has a distance between the windward end and the windward end of the first counter electrode that is the distance between the windward end and the windward side of the first counter electrode. It can be characterized in that it is provided closer than the distance.
By doing this, the dust collection efficiency can be further improved.

  Furthermore, the ratio of the second electrode area to the first electrode area may be characterized by being more than 50% and less than 90%.

  In such a charging device, the high voltage electrode may be provided on the windward side with respect to a center or a center of the first counter electrode in the ventilation direction.

  In such a charging device, the plurality of counter electrodes may be characterized in that the first counter electrodes and the second counter electrodes are alternately arranged.

  In such a charging device, the high voltage electrode may have a circular cross-sectional shape, and may have a diameter of 20 μm or more and 300 μm or less.

In such a charging device, the high voltage electrode may be characterized by having a cross section in which a rectangular corner portion is in an arc shape. In this case, the arc-shaped radius of curvature of the corner may be 5% or more and 50% or less of the short side length of the cross section.
The high voltage electrode may have a short side length of 50 μm or more and 100 μm.
The high-voltage electrode may be characterized in that the ratio of the long side length to the short side length of the cross section is more than 1 and 4 or less.

  In such a charging device, the high voltage electrode may be any of tungsten, copper, nickel, stainless steel, zinc, and iron, an oxide or alloy containing the metal as a main component, the metal, or the metal as a main component. It can be characterized in that it is made of any one of silver, gold and platinum noble metals plated on the surface thereof.

  For this purpose, the charging device to which the present invention is applied includes a plurality of plate-like counter electrodes arranged in a direction intersecting with the ventilation direction so that each surface is along the ventilation direction. Further, the charging device includes linear high-voltage electrodes provided between the plurality of counter electrodes. The plurality of high-voltage electrodes have a cross section in which rectangular corner portions are arc-shaped, and charge floating particles suspended in an air flow that ventilates between the plurality of counter electrodes and the plurality of high-voltage electrodes.

In such a charging device, the high-voltage electrode may be characterized in that a radius of curvature of an arc-shaped portion at a corner of a cross section is 5% or more and 50% or less of a short side length of the cross section.
The high voltage electrode may have a short side length of 50 μm or more and 100 μm.
The high-voltage electrode may be characterized in that the ratio of the long side length to the short side length is more than 1 and 4 or less.

  In such a charging device, the high-voltage electrode may be any of tungsten, copper, nickel, stainless steel, zinc, and iron, an oxide or alloy containing the metal as a main component, the metal, or the metal as a main component. It can be characterized in that it is composed of any of oxides plated with silver and any of noble metals of gold and platinum on the surface.

  From another point of view, the dust collecting apparatus to which the present invention is applied includes a charging unit including any one of the charging devices described above, and floating particles provided on the leeward side of the charging unit and charged by the charging unit. And a dust collection unit for collecting dust as dust. The dust collection unit includes a plurality of plate-shaped other counter electrodes and a plurality of plate-shaped other high-voltage electrodes provided between the plurality of other counter electrodes.

  From another viewpoint, the dust collecting apparatus to which the present invention is applied is provided with a charging unit including any one of the charging devices described above, and a leeward side provided on the leeward side of the charging unit and charged by the charging unit. And a dust collection unit for collecting fine particles as dust. And the said dust collection part is equipped with a dust collection filter. And, the dust collection filter may be characterized by being electret-processed.

  According to the present invention, it is possible to provide a charging device or the like in which the charging efficiency of suspended particles is improved while suppressing the concentration of generated ozone.

It is a figure which shows an example of the dust collector to which 1st Embodiment is applied. FIG. 5 is a diagram for explaining in detail the charging unit of the first embodiment. (A) is a perspective view of the charging portion, (b) is a cross-sectional view of the charging portion (Y-direction cross section), (c) and (d) are side views of the counter electrode. FIG. 6 is a view for explaining a charging unit of Comparative Example 1; (A) is a perspective view of a charging part, (b) is sectional drawing (Y direction sectional drawing) of a charging part. The table which shows the dust collection efficiency and ozone concentration in each electric discharge current in the dust collection device provided with the countering electrode in the charging part of Example 1, comparative example 1 and other examples, and a comparative example, and each charging part is there. It is a side view explaining the counter electrode of other examples. (A)-(d) show each of other countering electrodes. It is a graph which shows the relationship between the discharge current dependence of the dust collection efficiency in Example 1, Example 5, Comparative Example 1, and Comparative Example 2, and the dust collection efficiency and the ozone concentration. (A) shows the discharge current dependency of the dust collection efficiency, and (b) shows the relationship between the dust collection efficiency and the ozone concentration. With respect to Examples 1, 2 and 3 and Comparative Example 1 in which the counter electrodes having the openings are arranged (arranged) in a row, the relationship between the ratio of the openings and the dust collection efficiency is shown in each discharge current. It is a figure shown every. Compared with Comparative Examples 1 and Examples 1, 4, 5 and 6 in which counter electrodes having through holes with different diameters in the openings are arranged (arranged) in an array, the ratio of the openings and the dust collection efficiency Is a diagram showing the relationship of each discharge current. It is a table | surface which shows the dust collection efficiency and ozone concentration in each discharge current of a dust collector provided with each counter part of the charging part of Comparative Example 1 and Comparative Examples 4 and 5, and each charging part. It is a side view explaining the counter electrode in comparative examples 4 and 5. (A) shows the counter electrode in comparative example 4, (b) shows the counter electrode in comparative example 5. Comparative Example 1 and Comparative Example 4 and Comparative Example 5 in which the counter electrodes having openings on the upstream side are arranged (arranged) in a row are arranged in the relationship between the ratio of the opening and the dust collection efficiency for each discharge current. FIG. In Example 1, Example 3, and the comparative example 1, it is a figure which shows the relationship of the measured ion number and the discharge current in a charge part. It is a figure which shows an example of the dust collector to which 2nd Embodiment is applied. FIG. 18 is a view for explaining in detail the charging unit of the eighth embodiment. (A) is a perspective view of the charging portion, (b) is a cross-sectional view of the charging portion (Y-direction cross-sectional view), (c) is a cross-sectional view of the high voltage electrode. The dust collection efficiency and the ozone concentration at each discharge current in the dust collecting apparatus provided with the high voltage electrode and the counter electrode in the charging unit of Example 8, Comparative Example 1 and the other embodiments, and the comparative example FIG. FIG. 18 is a view for explaining charging units of Example 9 and Comparative Examples 6 and 7; (A) shows Example 9, (b) shows Comparative Example 6, and (c) shows Comparative Example 7. It is a graph which shows the relationship between discharge current dependence of the dust collection efficiency in Example 8, Example 9, and Comparative Example 1, and the relationship between dust collection efficiency and ozone concentration. (A) shows the discharge current dependency of the dust collection efficiency, and (b) shows the relationship between the dust collection efficiency and the ozone concentration. It is a graph which shows the relationship between the discharge current dependence of the dust collection efficiency in Example 8, Comparative Example 1, Comparative Example 6, and Comparative Example 7, and the dust collection efficiency and ozone concentration. (A) shows the discharge current dependency of the dust collection efficiency, and (b) shows the relationship between the dust collection efficiency and the ozone concentration. It is a figure which shows an example of the dust collector to which 3rd Embodiment is applied.

Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings.
First Embodiment
FIG. 1 is a view showing an example of a dust collecting apparatus 1 to which the first embodiment is applied.
The dust collecting apparatus 1 to which the first embodiment is applied includes a charging unit 10, a dust collecting unit 20, a fan 30, and a case 40 for housing these. Here, the case 40 is indicated by a broken line, and the configurations of the charging unit 10 and the dust collection unit 20 provided inside the case 40 can be seen. The dust collecting apparatus 1 is a two-stage electric dust collecting system in which functions are separated from the charging unit 10 and the dust collecting unit 20. Here, the charging unit 10 and the dust collection unit 20 may be configured as a detachable unit.
Dust collection device 1 further includes a power supply unit that supplies high voltage to charging unit 10 and dust collection unit 20, and a control unit that controls charging unit 10, dust collection unit 20, fan 30, and the power supply unit. However, the description is omitted here. The charging unit 10 provided in the dust collection device 1 to which the first embodiment is applied is an example of a charging device.

  Here, the direction of air flow (ventilation) is set from the charging unit 10 to the dust collection unit 20 as indicated by the arrows (from left to right in the paper of FIG. 1). (Z direction described later). Ventilation is performed by a fan 30 provided on the downstream side (downwind side) of the dust collection unit 20 in the ventilation direction.

(Charging unit 10)
The charging unit 10 includes a plurality of high voltage electrodes 110 and a plurality of counter electrodes 120 provided to face each of the plurality of high voltage electrodes 110. Since the high voltage electrode 110 is an electrode to which a high voltage is applied, it is also called a high voltage electrode, and since it is an electrode that generates a discharge, it may also be called a discharge electrode. In addition, since the counter electrode 120 may be grounded (GND), it may be referred to as a ground electrode.

The high voltage electrode 110 is formed of a conductive wire-like member (linear member).
The counter electrode 120 is composed of a plate-like member (plate-like member) having conductivity. And the counter electrode 120 is provided in the direction in which the flat surface of the plate-like member follows the ventilation direction. In FIG. 1, the plane of the counter electrode 120 does not necessarily match the ventilation direction (the angle between the plane of the counter electrode 120 and the ventilation direction is 0 °). The angle between the plane and the ventilation direction may be less than 90 °.

  The counter electrodes 120 have different shapes every other sheet. That is, the even-numbered counter electrodes 120 along the X direction have the openings 130, and the area (hereinafter referred to as the electrode area) of the portion functioning as an electrode is smaller than the odd-numbered counter electrodes 120. It is configured to be That is, the opposite electrodes 120 having different electrode areas are alternately arranged in the direction crossing the ventilation direction.

Hereinafter, the charging unit 10 described later as the first embodiment will be described.
In the charging unit 10 according to the first embodiment, the odd-numbered counter electrodes 120 are referred to as "opposite electrode 120A" (sometimes referred to as "A"), and the even-numbered counter electrodes 120 are referred to as "B". There is a case. In the counter electrode 120B, the opening 130 is formed by a through hole 131 described later. The counter electrode 120B is configured to have an electrode area smaller than that of the counter electrode 120A by providing the through holes 131.

  Here, it is assumed that the high voltage electrode 110 is indicated by "*". Then, in the charging unit 10 of the first embodiment in the dust collection device 1 shown in FIG. 1, the high voltage electrode 110 and the counter electrode 120 are A-*-B-*-A-*-B-*-A-*-. It is arrange | positioned by the arrangement | sequence of B-*-A. Here, the alternate arrangement of the counter electrodes 120 having different electrode areas in this manner is referred to as “separate row”. On the other hand, the arrangement of the counter electrodes 120 having the same electrode area is referred to as "all rows".

(Dust collection unit 20)
The dust collection unit 20 includes a plate-like high-voltage electrode 210 whose surface is coated with a film of an insulating material and a plate-like counter electrode 220 having conductivity, which are alternately stacked. The counter electrode 220 may have any form as long as the charge of the charged particles is released, and may be coated with a conductive resin film or the like. A ventilation direction is between the high voltage electrode 210 and the counter electrode 220. Again, the counter electrode 220 may be referred to as a ground electrode because it may be grounded (GND).
A high voltage of direct current (DC) is applied between the high voltage electrode 210 and the counter electrode 220 by a high voltage power supply (not shown). Then, the floating fine particles charged by the charging unit 10 adhere to the surface of the counter electrode 220 by electrostatic force. Thus, suspended particles are collected.

  Note that polyethylene, polyethylene terephthalate (PET), polytetrafluoroethylene (PTFE) or the like can be used for the film of the insulating material covering the surface of the high voltage electrode 210.

(Case 40)
In the case 40, an inlet 41 is provided on the charging unit 10 side on the upstream side (windward side) in the ventilation direction, and an outlet 42 is provided on the dust collecting unit 20 side on the windward side. The inlet 41 may be provided with a mesh, a grid, or the like. A mesh (net), a grid or the like provided at the inlet 41 may be provided so as to reduce the resistance to ventilation while preventing the user from contacting the charging unit 10. In addition, the inlet portion 41 may be provided with a pre-filter that suppresses the entry of particles having a large shape.
The fan 30 is provided at the outlet 42 on the downwind side provided in the housing 40.

That is, the flow of air (ventilation) enters from the inlet 41 on the charging unit 10 side of the housing 40, and passes through the charging unit 10 and the dust collecting unit 20 to the outlet where the fan 30 of the housing 40 is provided. Exit from 42 Then, for convenience of explanation, as shown in FIG. 1, the ventilation direction is taken as the Z direction, and the direction orthogonal to the Z direction is taken as the X direction and the Y direction.
In addition, as long as ventilation is not inhibited, the dust collection device 1 may be placed in any direction.

  The housing 40 is made of, for example, a resin material such as ABS (acrylonitrile, butadiene, and a styrene copolymer).

  Then, a high voltage of direct current (DC) is applied between the high voltage electrode 110 and the counter electrode 120 from a high voltage power supply (not shown), whereby corona discharge (discharge) is generated between the high voltage electrode 110 and the counter electrode 120. Occurs. Then, the ions generated by the generated corona discharge adhere to the floating particles, thereby charging (charging) the floating particles.

Example 1
FIG. 2 is a diagram for explaining the charging unit 10 of the first embodiment in detail. 2A is a perspective view of the charging unit 10, FIG. 2B is a cross-sectional view of the charging unit 10 (Y-direction cross-sectional view), and FIG. 2C is a side view of the counter electrode 120A. (D) is a side view of the counter electrode 120B.
The charging unit 10 according to the first embodiment includes the high voltage electrode 110 and the counter electrodes 120A and 120B having different electrode areas.

  As shown in FIGS. 2A and 2B, the high voltage electrode 110 is made of, for example, a tungsten (W) wire having a diameter of 90 μm. That is, the cross section of the high voltage electrode 110 is a circle. In addition to tungsten, the high voltage electrode 110 may be a metal such as copper, nickel, stainless steel, zinc, iron, or an alloy containing any of these metals as a main component. Furthermore, the high-voltage electrode 110 may be one obtained by plating a noble metal such as silver, gold, or platinum on the surface of an oxide or an alloy containing these metals or these metals as a main component. The characteristics of the high voltage electrode 110 may be stable when it is tungsten oxide. The high-voltage electrode 110 preferably has a diameter of 20 μm or more and 300 μm or less.

The counter electrode 120A has a plate shape without the opening 130. On the other hand, the counter electrode 120 </ b> B includes the opening 130 and the through hole 131 in the opening 130. The counter electrode 120A not provided with the through hole 131 and the counter electrode 120B provided with the through hole 131 are arranged (arranged) in a row. As described above, it is A-*-B-*-A-*-B-*-A. This array is simply denoted AB. The same applies to others.
The opening 130 refers to all the through holes 131 on the counter electrode 120A. In FIG. 1 and FIG. 2D, the opening 130 is described so as to surround the through hole 131 for convenience.

The counter electrodes 120A and 120B are made of, for example, aluminum. The counter electrode 120 may be made of metal other than aluminum, such as stainless steel (SUS) or nickel alloy, or carbon.
The widths W _A and W _B , which are the lengths in the Z direction of the counter electrodes 120A and 120B, are both 10 mm, for example. Although the widths W _A and W _B may be other than 10 mm, the smaller the width is, the smaller the charging unit 10 can be. The length of the counter electrode 120 (the length in the Y direction) may be set according to the size of the dust collection device 1. For example, it is 400 mm.

As shown in FIG. 2C, the counter electrode 120A has a plate shape without the opening 130. On the other hand, as shown in FIG. 2D, the counter electrode 120B is provided with an opening 130. The opening 130 is provided with a plurality of through holes 131 arranged in the Y direction. Here, the planar shape of the through hole 131 is circular. Through holes 131, for example a diameter _{d B} is 3mm (3mmφ). Note that the through hole 131 may have a non-circular planar shape, and includes a planar shape such as an ellipse or a quadrangle. The shape of the through hole 131 is preferably a shape in which the electric field is not concentrated.

  Here, the outer shape is the same as that of the counter electrodes 120A and 120B. Therefore, the ratio of the area occupied by all the through holes 131 (openings 130) in the counter electrode 120 to the area of the outer shape of the counter electrode 120 is referred to as an opening ratio or simply as a ratio. That is, in the case where the through hole 131 is not provided, that is, the counter electrode 120A has an opening ratio (ratio) of 0%. On the other hand, the counter electrode 120 B has an opening ratio (ratio) determined by the area of the through hole 131. In the counter electrode 120B in the first embodiment, the opening ratio (ratio) is 13.8%.

And as shown to FIG. 2B, the high voltage electrode 110 is provided in the windward side (-Z direction side) in the width direction (Z direction) of the counter electrode 120. As shown in FIG. The high voltage electrode 110 in the width direction of the counter electrode 120 is disposed windward side of the distance from the end D _F, from the end on the leeward side at a distance D _B. Note that D _F + D _B = W _A or W _B. And, D _F : D _B is, for example, 3: 7. In addition, you may provide in another position. The reason why the high voltage electrode 110 is offset to the windward side in the width direction of the counter electrode 120 as described above will be described later.

Then, the distance _{D G} of the counter electrode 120A, 120B and the high voltage electrode 110 is, for example, 10 mm.

(Comparative example 1)
FIG. 3 is a view for explaining the charging unit 10 of Comparative Example 1. As shown in FIG. FIG. 3A is a perspective view of the charging unit 10, and FIG. 3B is a cross-sectional view (cross-sectional view in the Y direction) of the charging unit 10. As shown in FIG. In Comparative Example 1, all the counter electrodes 120 are the counter electrodes 120A shown in FIG. 2 (c). That is, the charging unit 10 of Comparative Example 1 shown in FIG. 3A replaces the counter electrode 120B (“B”) with the counter electrode 120A (“A”) in Example 1 shown in FIG. 2A. Configuration. That is, the counter electrodes 120 are arranged (arranged) in all the rows of A-*-A-*-A-*-A-*-A. This is simply denoted as AA.

  FIG. 4 is a table showing dust collection efficiencies and ozone concentrations at discharge currents of Example 1, Comparative Example 1 and other Examples and Comparative Examples. The dust collection efficiency and the ozone concentration indicate the results of measurement at different discharge currents of the charging unit 10. Here, the high voltage electrode 110 is a tungsten wire with a diameter of 90 μm (circular cross section). The voltage between the high voltage electrode 210 and the counter electrode 220 of the dust collection unit 20 was 6 kV. In addition, the wind speed in the ventilation direction was 1 m / sec. The discharge current was 150 μA, 250 μA and 450 μA.

  The dust collection efficiency (%) is determined by using a particle counter for the number of suspended particles on the upstream side (before entering charging unit 10) and the downstream side (after exiting from dust collection unit 20) of the ventilation direction of It measured and asked for. Moreover, the ozone concentration (ppb) was measured on the downstream side (after leaving the dust collection unit 20) of the ventilation direction of the dust collection device 1 using an ozone densitometer.

As described above, in the charging portion 10 of Example 1, the counter electrode 120 is a row of AB, and in the comparative example 1, the counter electrode 120 is an entire row of AA.
In addition, the counter electrode 120 of the charging unit 10 in the other Examples 2 to 7 is the AC of Example 2, the AD of Example 3, the AE of Example 4 and the AE of Example 4. Arrangement of AF separations, Example 6 separation of AG separations, and Example 7 separation of AH separations (arrangement). That is, in Examples 1 to 7, the arrangement (arrangement) of the rows of the opposing electrodes 120 having different shapes (different electrode areas) is used.
Below, the counter electrodes 120C, 120D, 120E, 120F, 120G, and 120H in Examples 2-7 are explained.

  FIG. 5 is a side view illustrating another counter electrode 120C, 120D, 120E, 120F, 120G, and 120H. 5A shows the opposite electrode 120C, FIG. 5B shows the opposite electrode 120D, FIG. 5C shows the opposite electrodes 120E, 120F, and 120G, and FIG. 5D shows the opposite electrode 120H.

  In the counter electrode 120C shown in FIG. 5A, through holes 131 with a diameter of 3 mm (3 mmφ) are provided in two rows in a zigzag in the Y direction. Thus, the through hole 131 is provided on the entire surface of the counter electrode 120C. In this case, the opening ratio is 27.6%.

The counter electrode 120D shown in FIG. 5B is configured by a notch 132 in which the opening 130 is provided on the downwind side (Z direction). Here, the counter electrode 120D is configured by cutting out a part of the counter electrode 120A. That is, the windward end of the counter electrode 120D is at the same position as the windward end of the counter electrode 120A in the Z direction (on the Z axis), and the windward end of the counter electrode 120D is the counter electrode 120A. And a short position (position with a small coordinate value) in the Z direction (on the Z-axis).
Here, the depth d _W of the notch 132 is set to 5 mm. Thus, the opening ratio is 50%.
The counter electrode 120D may be configured by a metal width minus the depth d _W the width W _B of the notch 132. That is, the width in the ventilation direction of the counter electrode 120D may be narrower than the width in the ventilation direction of the counter electrode 120A.
The opening ratio is set by adjusting the depth d _W.

Similar to the counter electrode 120C shown in FIG. 5A, in the counter electrodes 120E, 120F, and 120G illustrated in FIG. 5C, a plurality of through holes 131 with a diameter d _B are provided on the entire surface of the counter electrode 120. There is. In the counter electrode 120E, it is provided through hole 131 of 0.25 mm (0.25 mm) diameter _{d B.} The opening ratio of the counter electrode 120E is 10%. In the counter electrode 120F, it is provided through hole 131 having a diameter _{d B} is 0.75mm (0.75mmφ). The opening ratio of the counter electrode 120F is 36%. In the counter electrode 120G, it is provided through hole 131 of 1.5 mm (1.5 mm [phi]) in diameter _{d B.} The opening ratio of the counter electrode 120G is 50%.

In the counter electrode 120H shown in FIG. 5 (d), similarly to the counter electrode 120B shown in FIG. 2 (a), (d) , provided in the through hole 131 is downwind of the diameter _{d B} is 6 mm (diameter: 6 mm) It is done.

  In addition, the counter electrodes 120 of the charging unit 10 in the other comparative examples 2 and 3 shown in FIG. 4 are all columns of BB in Comparative Example 2 and all columns of CC in Comparative Example 3. That is, Comparative Examples 1 to 3 are all the rows of the opposing electrodes 120 having the same shape (the same electrode area). The counter electrode 120B is shown in FIG. 2 (d), and the counter electrode 120C is shown in FIG. 5 (a).

In the following, based on the results shown in FIG. 4, a remarkable example is illustrated and described.
FIG. 6 shows the discharge current dependency of the dust collection efficiency in Example 1 (AB), Example 5 (AF), and Comparative Example 1 (AA), Comparative Example 2 (BB), and the dust collection efficiency and the ozone concentration. Is a graph showing the relationship with 6 (a) shows the discharge current dependency of the dust collection efficiency, and FIG. 6 (b) shows the relationship between the dust collection efficiency and the ozone concentration. In FIG. 6A, the horizontal axis is the discharge current (μA), and the vertical axis is the dust collection efficiency (%). In FIG. 6B, the horizontal axis is the ozone concentration (ppb), and the vertical axis is the dust collection efficiency (%).

In FIG. 6A, in Comparative Example 1 (AA), the dust collection efficiency increases with the discharge current. However, the dust collection efficiency does not reach 99% unless the discharge current reaches 450 μA.
Further, in Comparative Example 2 (BB), the dust collection efficiency in the range where the discharge current is small is higher than that of Comparative Example 1 (AA). However, as in Comparative Example 1 (AA), the dust collection efficiency does not reach 99% unless the discharge current reaches 450 μA.
That is, as shown in Comparative Example 2 (BB), when the counter electrodes 120B provided with the openings 130 (through holes 131) on the downwind side are arranged (arranged) in all rows, the dust collection efficiency is in a range where the discharge current is small. It tends to improve. However, the effect is small.

  On the other hand, in Example 1 (AB) and Example 5 (AF) in which the opposite electrodes 120 having different opening ratio (ratio) are arranged (arranged) in a row, the dust collection efficiency is also within the range where the discharge current is small. It improves compared with comparative example 1 (AA) and comparative example 2 (BB). In particular, in Example 1 (AA), even when the discharge current is 150 μA, a dust collection efficiency of 98.88% is obtained.

  Further, from Example 1 (AB) and Comparative Example 2 (BB), the counter electrodes 120B provided with the openings 130 (through holes 131) used in Example 1 (AB) on the downwind side are arranged in all rows ( Even in the arrangement, it is understood that a large improvement in the dust collection efficiency can not be expected in a small range where the discharge current is 300 μA or less. From Example 1 (AB) and Example 5 (AF) arranged (arranged) in both rows, Example 1 using counter electrode 120B having opening 130 (through hole 131) on the downwind side. As compared with Example 5 (AF) in which the opening 130 (through hole 131) is provided on the entire surface in the case of (AB), it is understood that the dust collection efficiency is improved even if the discharge current is as small as 150 μA.

  That is, the discharge current is small by arranging (arranging) the counter electrode 120B having the opening 130 (through hole 131) on the downwind side in the charging unit 10 and the counter electrode 120A having no opening 130 in a row. It can be seen that the dust collection efficiency in the range (150 μA) is improved. It is considered that this is because the charging (charging) efficiency with respect to the floating particles is improved in the range (150 μA) where the discharge current is small.

  Further, from the relationship between the dust collection efficiency and the ozone concentration shown in FIG. 6B, the ozone concentration is low in Example 1 (AB) and Example 5 (AF) arranged (arranged) in both rows. It can be seen that high dust collection efficiency can be obtained while maintaining As can be seen from the discharge current dependency of the dust collection efficiency shown in FIG. 6A, high dust collection efficiency can be obtained at low discharge current in Example 1 (AB) and Example 5 (AF). It is for. Conversely, as can be seen from the discharge current dependency of the dust collection efficiency shown in FIG. 6A, in Comparative Example 1 (AA) and Comparative Example 2 (BB), in order to obtain high dust collection efficiency, Since it is necessary to increase the concentration, the ozone concentration will increase. That is, in Example 1 (AB) and Example 5 (AF), a dust collection efficiency of 95% or more can be obtained in a range far below the ozone concentration of the environmental standard value (50 ppb) of 4.0 ppb or less.

FIG. 7 shows the relationship between the opening ratio (ratio) and the dust collection efficiency with respect to Examples 1, 2 and 3 and Comparative Example 1 in which the counter electrodes provided with the openings 130 are arranged (arranged) in a row. Is shown for each discharge current. The horizontal axis is the ratio (%), and the vertical axis is the dust collection efficiency (%). The discharge current is shown for 150 μA, 250 μA, and 450 μA.
Comparative Example 1 (AA) has a ratio of 0%. The counter electrode 120B of Example 1 (AB) is provided with a through hole 131 of 3 mmφ in the opening 130 on the downwind side, and the ratio is 13.8%. The counter electrode 120C of Example 2 (AC) is provided with a through hole 131 of 3 mm in diameter on the entire surface, and the ratio is 27.6%. In the counter electrode 120D of Example 3 (AD), a notch 132 is provided on the downwind side, and the ratio is 50%.

As shown in FIG. 7, in Example 1 (AB), Example 2 (AC), and Example 3 (AD) in which counter electrodes 120 having openings 130 are arranged (arranged) in a row, the openings 130 are used. The dust collection efficiency is high at a low discharge current (e.g., 150 [mu] A) as compared with Comparative Example 1 (AA) having no. From this, when the opening ratio (ratio) is 10% or more and 50% or less, the dust collection efficiency at a low discharge current (for example, 150 μA) is improved. However, Example 1 (AB) having a ratio of 13.8% and Example 3 (AD) having a ratio of 50% have higher dust collection efficiency at a lower discharge current than Example 2 (AC) having a ratio of 27.6%. From the above, it is understood that the dust collection efficiency is not improved as the opening ratio (ratio) is larger. It is understood that the opening 130 (the through hole 131 or the notch 132) may be provided on the downwind side. In addition, when the opening part 130 calls the ratio of the through-hole 131 per unit area the opening degree, it can be grasped that the opening degree is higher on the leeward side than on the windward side. That is, the through holes 131 may be provided such that the opening degree increases from the windward side to the windward side. For example, the through hole 131 so that the diameter d _B increases toward the downstream side from the windward side may be provided at a defined spacing, the density of the through holes 131 (number) is toward the windward side downwind It may be made larger.

  In the case of the counter electrode 120D in which the opening 130 is provided by narrowing the width by the notch 132 or the like, the distance between the windward end of the counter electrode 120D and the windward end of the counter electrode 120A is The distance may be smaller than the distance between the leeward end of the counter electrode 120D and the leeward end of the counter electrode 120A.

FIG. 8 is an opening compared to Comparative Example 1 and Examples 1, 4, 5, and 6 in which the counter electrodes 120 having through holes 131 having different diameters d _B are arranged (arranged) in the opening 130. It is a figure which shows the relationship between a ratio (ratio) and dust collection efficiency for every discharge current. The horizontal axis is the ratio (%), and the vertical axis is the dust collection efficiency (%). The case of the discharge current of 150 μA, 250 μA, and 450 μA is shown.

Comparative Example 1 (AA) does not have the through hole 131 and has a ratio of 0%. Counter electrode 120E of Example 4 (AE) has a through-hole 131 of 0.25mm diameter _{d B} is provided on the entire surface, a 10% ratio. Counter electrode 120B of Example 1 (AB), the through hole 131 of 3mm diameter _{d B} is provided on the downstream side, a 13.8% percentage. Ratio 18%, although not shown in FIG. 4, the through hole 131 of 0.5mm diameter _{d B} is provided on the entire surface. Counter electrode 120F in Example 5 (AF) has a through hole 131 having a diameter _{d B} is 0.75mm is provided on the entire surface, a 36% ratio. Counter electrode 120D of Example 6 (AD), the through hole 131 of 1.5mm diameter _{d B} is provided on the entire surface, is 50% ratio. And, in the case of Example 1 (AB), Example 4 (AE), Example 5 (AF), Example 6 (AD), and the ratio 18%, it is the arrangement (arrangement) of the rows.

At a high discharge current (450 μA), a large difference in dust collection efficiency due to the diameter d _B of the through hole 131 provided in the counter electrode 120 can not be seen. However, the low discharge current (150 .mu.A, 250 .mu.A), in accordance with the diameter _{d B} of the through hole 131 is increased, it tends to improve dust collection efficiency. However, the dust collection efficiency in Example 1 (AB) in which the through hole 131 of 3 mmφ is provided on the downwind side is the highest.

In the cases of Example 1 (AB), Example 4 (AE), Example 5 (AF), Example 6 (AD), and a ratio of 18%, an improvement in the dust collection efficiency is observed compared to Comparative Example 1 (AA). . From this result and the result of Example 7, the diameter d _B of the through hole 131 of the opening 130 where improvement of the dust collection efficiency can be seen is not less than 2.5% and 60% of the width W _B of the counter electrode 120 in the ventilation direction. It is below. Moreover, the opening ratio at which the improvement of the dust collection efficiency is observed is 10% or more and 50% or less.

Therefore, even when the counter electrode 120D of the opening 130 is configured with notches 132, a depth _{d W} of the notch 132, more than 10% of the width _{W B} of the counter electrode 120D and 50% or less It should be set. That is, the ratio of the electrode area of the counter electrode 120D to the counter electrode 120A may be more than 50% and less than 90%.

Up to this point, when the counter electrodes 120 provided with the openings 130 on the downwind side are arranged (arranged) in a row (Example 1 (AB), Example 3 (AD), Example 7 (AH)) and openings When the counter electrodes 120 having the entire surface 130 are arranged (arranged) in a row (Example 2 (AC), Example 4 (AE), Example 5 (AF), and Example 6 (AG)) did.
Next, the case where the counter electrodes 120 provided with the openings 130 on the windward side are arranged (arranged) in a row will be described.

FIG. 9 shows the dust collection efficiency and the ozone concentration at the discharge current of each of the counter electrode 120 in the charging unit 10 of Comparative Example 1 and Comparative Examples 4 and 5 and the dust collection device 1 including each charging unit 10. It is a table. In Comparative Example 1, as described above, the counter electrode 120 is an array of all the rows of AA. On the other hand, in Comparative Examples 4 and 5, Comparative Example 4 is an array of AB ', and Comparative Example 5 is an array of AD'. The discharge current is 150 μA, 250 μA, 450 μA.
Hereinafter, the counter electrodes 120B 'and 120D' in the comparative examples 4 and 5 will be described.

  FIG. 10 is a side view for explaining the counter electrodes 120B ′ and 120D ′ in the comparative examples 4 and 5. FIG. 10A shows a counter electrode 120B ′ in Comparative Example 4, and FIG. 10B shows a counter electrode 120D ′ in Comparative Example 5.

In the opposite electrode 120B ′ shown in FIG. 10A, the through holes 131 with a diameter of 3 mm (3 mmφ) are provided in a line in the Y direction on the windward side. That is, the opposite electrode 120B 'has a structure in which the upwind side and the downwind side of the opposite electrode 120B shown in FIG. 2D are switched. In this case, the ratio is 13.8%.
The counter electrode 120D 'shown in FIG. 10B is formed of a notch 132' in which the opening 130 is provided on the windward side. That is, the opposite electrode 120D 'has a structure in which the upwind side and the downwind side of the opposite electrode 120D shown in FIG. 4B are switched. In this case, the ratio is 50%.
The ratio of Comparative Example 1 (AA) is 0%.

FIG. 11 shows aperture ratios (ratios) in Comparative Example 1 (AA) and Comparative Example 4 (AB ') and Comparative Example 5 (AD') in which the counter electrodes having the openings upstream are arranged (arranged) in the opposite rows. And the dust collection efficiency for each discharge current. The horizontal axis is the ratio (%), and the vertical axis is the dust collection efficiency (%). The discharge current is 150 μA, 250 μA, 450 μA.
From FIG. 11, even if the opening 130 (through hole 131, notch 132) is provided on the windward side as in Comparative Example 4 (AB ′) and Comparative Example 5 (AD ′), the opening is not caused by the discharge current. The improvement of the dust collection efficiency is not seen in comparison example 1 which does not have 130. This is because there is no counter electrode 120 in the portion facing the high voltage electrode 110, and it is difficult to apply an electric field.
That is, it is understood that it is preferable to provide the opening 130 on the downwind side. When the opening 130 is configured by the through hole 131, at least the center of gravity of the through hole 131 may be on the leeward side of the high voltage electrode 110. The center of gravity of the through hole 131 refers to the center of gravity when the through hole 131 is not a hole but a plate-like member. If the planar shape of the through hole 131 is a circle, the center of gravity of the through hole 131 is the center of the through hole 131.

(Measurement of the number of ions)
The improvement of the dust collection efficiency at a low discharge current (such as 150 μA) is considered to be due to the increase in the number of ions generated (the number of ions) at a low discharge current. That is, as for the improvement of the dust collection efficiency, it is considered that the number of floating fine particles to which the ions are attached is increased by the increase of the number of generated ions, and the dust collection efficiency is improved.
In order to confirm this, in Example 1 (AB), Example 3 (AD) and Comparative Example 1 (AA), the number of generated ions (number of ions) generated from the charging unit 10 was measured. In Example 1 (AB) and Example 3 (AD), the counter electrodes 120 provided with the openings 130 on the downwind side are arranged in a row. The comparative example 1 (AA) is a case where the counter electrodes 120 not provided with the openings 130 are arranged in all the rows.

  Here, in a state in which the dust collection unit 20 in the dust collection device 1 is not present, the number of ions generated from the charging unit 10 was measured. At a wind speed of 1 m / sec, the number of ions generated in the charging unit 10 was measured by an ion counter provided 30 cm from the charging unit 10 on the downwind side.

FIG. 12 is a graph showing the relationship between the number of ions measured and the discharge current in the charging unit 10 in Example 1 (AB), Example 3 (AD), and Comparative Example 1 (AA). The horizontal axis is the discharge current (μA), and the vertical axis is the number of ions (× 1000 ions / cm ³ ). The number of ions on the vertical axis is an average value of measured values obtained by sampling every 10 seconds for 10 minutes at discharge currents of 150 μA, 250 μA, 350 μA, and 450 μA.

From FIG. 12, Example 1 (AB) and Example 3 (AD) have many ion numbers with respect to any discharge current compared with Comparative Example 1 (AA). In particular, the difference in the number of ions is large at low discharge currents (150 μA, 250 μA).
From this, it can be seen that the number of ions is increased by arranging the counter electrodes 120 provided with the openings 130 on the downwind side in a row.

  Ions are generated in the discharge space very near the high voltage electrode 110. Then, the ions move downwind with the ventilation. At this time, the ions adhere to the floating particles, and the floating particles are charged (charged). Therefore, as the number of ions increases, the number of charged floating particles also increases. The dust collection efficiency is improved by increasing the number of charged suspended particles.

Here, in Example 1 (AB), Example 3 (AD), and Comparative Example 1 (AA), the high voltage electrode 110 has the same configuration. That is, the high voltage electrode 110 is a tungsten wire with a diameter of 90 μm. And Example 1 (AA) and Example 3 (AD) have the opening part 130 on the downwind side. That is, in the vicinity of the high voltage electrode 110, a portion other than the opening 130 of the counter electrode 120 is opposed. Then, the distance _{D G} between the high voltage electrode 110 and the counter electrode 120 is also the same, it is 10 mm. From this, it is considered that there is no difference in the discharge volume of the discharge generated in the vicinity of the high-voltage electrode 110 in Example 1 (AB), Example 3 (AD) and Comparative Example 1 (AA). That is, it is considered that there is no difference in the number of generated ions.

  However, as shown in FIG. 12, in Example 1 (AB), Example 3 (AD), and Comparative Example 1 (AA), the number of ions measured on the downwind side is different. From this, it is conceivable that the ions generated in the high voltage electrode 110 disappear before reaching the dust collection unit 20. That is, ions are considered to be electrostatically attracted to the counter electrode 120 to adhere to or collide with it to lose charge (neutralize).

  And in Example 1 (AB) and Example 3 (AD) which provided the opening part 130 in downwind side, there are many numbers of ions measured by downwind side. From this, it is considered that the probability that ions adhere to or collide with the counter electrode 120 is reduced by the opening 130 provided on the leeward side of the counter electrode 120.

  As shown in Example 2 (AC), Example 4 (AE), Example 5 (AF), and Example 6 (AG) in FIG. 4, the opening 130 is provided on the entire surface. Even when the counter electrode 120 is used, the dust collection efficiency is improved as compared with Comparative Example 1 when arranged in a row.

  However, even when using the counter electrode 120 provided with the openings 130 as in Comparative Example 2 (BB) and Comparative Example 3 (CC), improvement in the dust collection efficiency is observed when arranged in all rows. Not. From this, by arranging the counter electrode 120 in which the opening 130 is provided and the counter electrode 120 in which the opening 130 is not arranged in a row, it is difficult for the ions to disappear (neutralize). That is, it is considered that the electric field generated between the adjacent counter electrodes 120 suppresses the loss (neutralization) of the ions.

  As the time (residence time) in which the ions exist in the charging unit 10 is longer, the probability of charging (charging) the suspended particles is higher. For this reason, it is preferable to dispose the high voltage electrode 110 on the windward side including the center of the counter electrode 120. Conversely, when the high voltage electrode 110 is shifted to the windward side from the windward end of the counter electrode 120, the electric field strength in the vicinity of the high voltage electrode 110 is unfavorably reduced.

  In addition, when the counter electrode 120 provided with the opening part 130 was used, turbulence (turbulence) of air flow arose as a factor which increases the number of ions, and it was also considered to be because ion residence time was extended. However, according to simulation and the like, no disturbance of the air flow was found in the air flow of 1 m / sec.

  In particular, the number of ions generated is small at low discharge current. However, by suppressing the disappearance (neutralization) of ions having a small number of generation, the charging (charging) efficiency of the floating fine particles is improved, and the dust collection efficiency can be increased even at a low discharge current. And ozone concentration can be suppressed low by making a discharge current low. That is, both high dust collection efficiency and suppression of ozone concentration can be achieved.

Second Embodiment
In the first embodiment, the configuration of the counter electrode 120 suppresses the disappearance (neutralization) of the ions generated in the discharge space around the high voltage electrode 110, thereby improving the dust collection efficiency at a low discharge current. .
In the second embodiment, the configuration of the high voltage electrode 110 improves the dust collection efficiency at a low discharge current with less generation of ozone.

FIG. 13 is a view showing an example of the dust collecting apparatus 2 to which the second embodiment is applied.
The dust collecting apparatus 2 to which the second embodiment is applied includes a charging unit 10, a dust collecting unit 20, a fan 30, and a case 40 for housing these. The dust collecting apparatus 2 is the same as the dust collecting apparatus 1 to which the first embodiment is applied except for the charging unit 10, so the same reference numerals are given and the description thereof is omitted. The charging unit 10 provided in the dust collection device 2 to which the second embodiment is applied is another example of the charging device.

(Charging unit 10)
The charging unit 10 includes a plurality of high voltage electrodes 111 and a plurality of counter electrodes 120 provided to face each of the plurality of high voltage electrodes 110.
The high voltage electrode 111 is configured of a conductive wire-like member (linear member). The high-voltage electrode 111 has a cross-sectional shape in which rectangular corner portions are arc-shaped. Here, this cross-sectional shape is described as an oval (oval shape) (Oval or Racing track shape).

  The counter electrode 120 is composed of a plate-like member (plate-like member) having conductivity. And the counter electrode 120 is provided in the direction in which the flat surface of the plate-like member follows the ventilation direction. Note that the opposing electrodes 120 having the same shape (the same electrode area) are arranged (arranged) in all the rows. In FIG. 13, the opposite electrode 120 is the opposite electrode 120A shown in FIG. 2 (c). The counter electrode 120A does not have the opening 130.

(Example 8)
FIG. 14 is a diagram for explaining the charging unit 10 of the eighth embodiment in detail. FIG. 14A is a perspective view of the charging unit 10, FIG. 14B is a cross-sectional view of the charging unit 10 (Y-direction cross-sectional view), and FIG. 14C is a cross-sectional view of the high voltage electrode 111.
As shown in FIG. 14 (c), oval cross section of the high voltage electrode 111, the corners of the rectangle is in the arcuate curvature radius r _W. The longitudinal direction of the quadrangle is referred to as long side length W _W , and the short side direction is referred to as short side length T _W.
And as shown to FIG. 14 (a), (b), the high voltage electrode 111 is arrange | positioned in the direction where the longitudinal direction of a square is parallel to the surface of the counter electrode 120A. The longitudinal direction of the quadrangle of the high voltage electrode 111 may be oblique to or perpendicular to the surface of the counter electrode 120A.

Corona discharge occurs in the high part of the electric field. The volume of this portion is referred to as the discharge volume. Then, in the linear high-voltage electrode 110 (see FIG. 2B) whose cross section is a circle, the smaller the diameter, the higher the electric field around the high-voltage electrode 110, and the smaller the discharge volume. Since the electric field is high, the number of generated ions increases, but the discharge volume is small, so the generation of ozone can be suppressed.
However, to reduce the diameter d _B of the high-voltage electrode 110, i.e. when thin, handling is difficult. For example, the high voltage electrode 110 made of tungsten (W) is difficult to attach to a predetermined portion. If it bends, it will be in the state as it is, and the discharge characteristic will become uneven. It is also fragile.

As shown in FIG. 14C, in the high-voltage electrode 111 having an oval cross section, corona discharge occurs in a region α where the curvature radius r _W of the cross section is small. And, in the region β which is the central portion in the longitudinal direction of the rectangle, corona discharge is less likely to occur. Therefore, by reducing the curvature radius r _W at the corner of the cross section, the discharge volume is reduced, and the generation of ozone can be suppressed while increasing the number of generated ions.

In the high-voltage electrode 111 in the charging portion 10 of the eighth embodiment, the curvature radius r _W of the corner portion of the cross section is 1/2 of the short side length T _W. High-voltage electrode 111, long side length _{W W} is 150 [mu] m, short side length _{T W} is 50 [mu] m. This is equivalent to dividing the diameter of the high-voltage electrode 110 having a circular cross-section into two and expanding the space. That is, the high-voltage electrode 110 with a diameter of 90 μm described in the first embodiment is the same as the diameter of 50 μm. With this cross-sectional shape, it is difficult to bend or break and handling is easy.

FIG. 15 shows discharges in the dust collecting apparatus 1 including the charging units 10 and the high voltage electrodes 110 and 111 and the counter electrode 120 in the charging units 10 of Example 8, Comparative Example 1 and other examples, and Comparative examples. It is a table | surface which shows the dust collection efficiency and ozone concentration in an electric current.
The comparative example 1 has been described in the first embodiment. Other Examples 9 and Comparative Examples 6 and 7 will be described next. The discharge current is 150 μA, 250 μA, 450 μA.

FIG. 16 is a view for explaining the charging unit 10 of the ninth embodiment and the sixth and sixth comparative examples. 16 (a) shows Example 9, FIG. 16 (b) shows Comparative Example 6, and FIG. 16 (c) shows Comparative Example 7. FIG.
The ninth embodiment is a combination of the oval high-voltage electrode 111 shown in the eighth embodiment and the counter electrodes 120A and 120B arranged in a row shown in the first embodiment of the first embodiment. .

  Comparative Example 6 uses a high voltage electrode 112 having a square cross section in place of the high voltage electrode 111 of the eighth embodiment. The high-voltage electrode 112 having a square cross section is made of stainless steel (SUS) and has a side of 70 μm. Comparative Example 7 uses a high voltage electrode 113 having a rectangular cross section instead of the high voltage electrode 111 of the eighth embodiment. The high-voltage electrode 113 having a rectangular cross section is made of stainless steel (SUS), and has a length of 150 μm in the longitudinal direction and a length of 50 μm in the lateral direction. The high voltage electrode 113 is disposed such that its longitudinal direction is parallel to the surface of the counter electrode 120A. In Comparative Examples 6 and 7, the counter electrodes 120A not provided with the openings 130 are arranged in all rows.

  FIG. 17 is a graph showing the discharge current dependency of the dust collection efficiency in Example 8 (AA), Example 9 (AB) and Comparative Example 1 (AA), and the relationship between the dust collection efficiency and the ozone concentration. . FIG. 17 (a) shows the discharge current dependency of the dust collection efficiency, and FIG. 17 (b) shows the relationship between the dust collection efficiency and the ozone concentration. In FIG. 17A, the horizontal axis is the discharge current (μA), and the vertical axis is the dust collection efficiency (%). In FIG. 17B, the horizontal axis is the ozone concentration (ppb), and the vertical axis is the dust collection efficiency (%).

In FIG. 17A, in Comparative Example 1 (AA), the dust collection efficiency increases with the discharge current. However, the dust collection efficiency does not reach 99% unless the discharge current reaches 450 μA.
On the other hand, in Example 8 (AA) using the oval high-voltage electrode 111, the dust collection efficiency is improved as compared with Comparative Example 1 (AA) even in the range where the discharge current is low (150 μA, 250 μA). There is. That is, it can be seen that the oval high-voltage electrode 111 increases the amount of ions generated.

  Further, in Example 9 (AB) using the oval high-voltage electrodes 111 and the counter electrodes 120A and 120B arranged in a row, the dust collection efficiency is further improved in the range where the discharge current is low. There is.

  And, from Example 8 (AA) and Example 9 (AB) in which high dust collection efficiency can be obtained with low discharge current from the relationship between dust collection efficiency and ozone concentration shown in FIG. 17 (b), high dust collection efficiency It can be seen that the ozone concentration can be suppressed low while maintaining the

  FIG. 18 shows the discharge current dependency of the dust collection efficiency in Example 8 (AA), Comparative Example 1 (AA), Comparative Example 6 (AA) and Comparative Example 7 (AA), and the dust collection efficiency and the ozone concentration Is a graph showing the relationship of FIG. 18 (a) shows the discharge current dependency of the dust collection efficiency, and FIG. 18 (b) shows the relationship between the dust collection efficiency and the ozone concentration. The vertical and horizontal axes are the same as in FIGS. 17 (a) and 17 (b).

  In FIG. 18A, Comparative Example 6 (AA) using a high voltage electrode 112 having a square cross section and Comparative Example 7 (AA) using a high voltage electrode 113 having a rectangular cross section have a low discharge current range. The dust collection efficiency is lower at (150 μA, 250 μA) than in Comparative Example 1 (AA). Further, also in the relation between the dust collection efficiency and the ozone concentration shown in FIG. 18 (b), the ozone concentration becomes high when it is attempted to obtain high dust collection efficiency in Comparative Example 6 (AA) and Comparative Example 7 (AA). I understand that it will end up.

As described above, the corners of the oval shape of the high-voltage electrode 111 are preferably arc-shaped and may not be 90 °. That is, the corners of the oval shape of the high voltage electrode 111 is 5% or more and 50% of the radius of curvature _{r W} is the short side length _{T W} (1/2) or is not more than arcuate. For example, short side length _{T W} is 50 .mu.m to 100 .mu.m, long side length _{W W} is 0.6Mm～1.0Mm. The long side length W _W is preferably more than 1 and 4 or less with respect to the short side length T _W. If the short side length T _W can be made small (thin), it becomes the same as using a thin high-voltage electrode 110 whose cross section is circular. Incidentally, long side length _{W W} is more than 4 against the short side length _{T W,} hard to work as a linear member.
The high voltage electrode 111 may be made of the same material as the high voltage electrode 110 described in the first embodiment.

  And, from Example 8 (AA) and Example 9 (AB) in which high dust collection efficiency can be obtained with low discharge current from the relationship between dust collection efficiency and ozone concentration shown in FIG. 17 (b), high dust collection efficiency It can be seen that the ozone concentration can be suppressed low while maintaining the

Third Embodiment
In dust collection device 1 to which the first embodiment is applied and dust collection device 2 to which the second embodiment is applied, dust collection unit 20 using static electricity using high voltage electrode 210 and counter electrode 220 Was equipped.
In the dust collection device 3 to which the third embodiment is applied, a dust collection filter is used.

FIG. 19 is a view showing an example of the dust collecting apparatus 3 to which the third embodiment is applied.
The dust collection device 1 to which the third embodiment is applied includes a charging unit 10, a dust collection filter 50, a deodorizing filter 60, a fan 30, and a case 40 for storing these. The dust collection unit 20 of the dust collection device 1 to which the first embodiment shown in FIG. 1 is applied is replaced with a dust collection filter 50. The deodorizing filter 60 may be appropriately provided on the front surface (upstream side) or the back surface (downstream side) of the charging unit 120 and the back surface (downstream side) of the dust collection filter 50.
The charging unit 10 is the same as the charging unit 10 shown as an example in the dust collecting apparatus 1 to which the first embodiment is applied and the dust collecting apparatus 2 to which the second embodiment is applied. May be

  The dust collection filter 50 is a fiber filter and is electret-processed, so that floating particles charged (charged) by the charging unit 10 are easily adsorbed. In addition, the dust collection filter 50 may have a large surface area by bending (pleating).

It is obvious that the numerical values shown in the embodiments 1 to 9 are examples and not limited thereto.
In addition, various combinations and modifications may be made without departing from the spirit of the present invention.

1, 2, 3 · · · · · dust collector, 10 · · · charging unit, 20 · · · dust collection unit, 30 · · · fan · 40 · · · housing 50, dust collection filter, 60 · deodorization filter, 110, 111, 112, 113, 210 ... High voltage electrode, 120, 120A to 120G, 120C ', 120D', 220 ... Counter electrode, 130 ... Opening, 131 ... Through hole, 132 ... Notch

Claims (24)

A plurality of plate-like counter electrodes arranged in a direction intersecting with the ventilation direction so that each surface is along the ventilation direction;
A plurality of linear high voltage electrodes respectively provided between the plurality of counter electrodes;
The plurality of counter electrodes is a first counter electrode in which one of at least one pair of adjacent counter electrodes has a first electrode area, and the other is set smaller than the first electrode area by an opening. A charging device, which is a second counter electrode having an electrode area of 2 and charges floating particles suspended in an air flow that ventilates between a plurality of the counter electrodes and a plurality of the high-voltage electrodes.   The charging device according to claim 1, wherein the opening of the second counter electrode is configured by a through hole.   The charging device according to claim 2, wherein an opening degree, which is an area of the through hole per unit area, of the second counter electrode is higher on the leeward side than on the windward side.   When the planar shape of the through hole at the opening is a circle, the second counter electrode has a diameter of 2.5% or more and 60% or less of the width of the second counter electrode in the ventilation direction. 4. The charging device according to claim 2, wherein the ratio of the area occupied by the through hole of the opening to the area of the second counter electrode is 10% or more and 50% or less.   The charging device according to any one of claims 2 to 4, wherein a center of gravity of the through hole at the opening of the second counter electrode is located on the leeward side of the high voltage electrode. A plurality of plate-like counter electrodes arranged in a direction intersecting with the ventilation direction so that each surface is along the ventilation direction;
A plurality of linear high voltage electrodes respectively provided between the plurality of counter electrodes;
In the plurality of counter electrodes, at least one of a pair of adjacent counter electrodes is a first counter electrode having a first electrode area, and the other is set to have a narrower width in the ventilation direction than the first counter electrode. A charging device for charging suspended particles suspended in an air flow which is a second counter electrode having a second electrode area and ventilates between a plurality of the counter electrodes and a plurality of the high-voltage electrodes.   The distance between the windward end of the second opposing electrode and the windward end of the first opposing electrode is determined by the distance between the windward end of the second opposing electrode and the windward side of the first opposing electrode. The charging device according to claim 6, which is provided near.   The charging device according to claim 6, wherein a ratio of the second electrode area to the first electrode area is more than 50% and less than 90%.   The charging device according to any one of claims 1 to 8, wherein the high voltage electrode is provided on the windward side including the center of the first counter electrode in the ventilation direction.   The charging device according to claim 1, wherein the plurality of counter electrodes are alternately arranged with the first counter electrode and the second counter electrode.   The charging device according to any one of claims 1 to 10, wherein the high voltage electrode has a circular cross-sectional shape and a diameter of 20 μm or more and 300 μm or less.   The charging device according to any one of claims 1 to 10, wherein the high voltage electrode has a cross section in which a rectangular corner has an arc shape.   13. The charging device according to claim 12, wherein an arc-shaped radius of curvature of the corner portion of the high-voltage electrode is 5% or more and 50% or less of a short side length of a cross section.   The charging device according to claim 12, wherein the high voltage electrode has a short side length of 50 μm or more and 100 μm.   15. The charging device according to claim 14, wherein a ratio of a long side length to a short side length of the high voltage electrode is more than 1 and 4 or less.   The high voltage electrode may be any metal of tungsten, copper, nickel, stainless steel, zinc, iron, an oxide or alloy containing the metal as a main component, silver, gold on the metal or an oxide containing the metal as a main component. The charging device according to any one of claims 11 to 15, wherein the charging device is formed of any one of platinum and platinum plated on the surface thereof. A plurality of plate-like counter electrodes arranged in a direction intersecting with the ventilation direction so that each surface is along the ventilation direction;
A plurality of linear high voltage electrodes respectively provided between the plurality of counter electrodes;
The charging device has a plurality of high-voltage electrodes having a cross section in which rectangular corner portions are arc-shaped, and charges suspended particles suspended in an air flow that ventilates between a plurality of the counter electrodes and a plurality of the high-voltage electrodes.   18. The charging device according to claim 17, wherein a radius of curvature of an arc-shaped portion at a corner of a cross section of the high voltage electrode is 5% or more and 50% or less of a short side length.   The charging device according to claim 17, wherein the high voltage electrode has a short side length of 50 μm or more and 100 μm.   20. The charging device according to claim 19, wherein a ratio of a long side length to a short side length of a cross section of the high voltage electrode is more than 1 and 4 or less.   The high voltage electrode may be any metal of tungsten, copper, nickel, stainless steel, zinc, iron, an oxide or alloy containing the metal as a main component, silver as the metal or an oxide containing the metal as a main component, and 21. The charging device according to any one of claims 17 to 20, wherein the charging device is made of any one of gold and platinum plated on the surface with a noble metal. A charging unit comprising the charging device according to any one of claims 1 to 21;
A plurality of plate-like other counter electrodes and a plurality of plate-like other high-voltage electrodes provided between the plurality of other counter electrodes, provided on the leeward side of the charging unit, And a dust collection unit for collecting floating fine particles charged by the unit as dust. A charging unit comprising the charging device according to any one of claims 1 to 21;
A dust collection device comprising: a dust collection filter; and a dust collection part provided on the downwind side of the charging part and collecting floating fine particles charged by the charging part as dust.   The dust collecting apparatus according to claim 23, wherein the dust collecting filter is electret-processed.

Images