CN111542396A - Charging equipment and dust remover - Google Patents

Abstract

Disclosed herein are a charging apparatus and a dust collector. The charging device includes a plurality of counter electrodes formed in a plate shape and arranged in a direction intersecting with a ventilation direction to allow respective surfaces of the plurality of counter electrodes to follow the ventilation direction, and a plurality of high-voltage electrodes formed in a line shape and mounted between the plurality of counter electrodes. The plurality of counter electrodes includes a first counter electrode having a first electrode area and a second counter electrode having a second electrode area smaller than the first electrode area. The first pair of electrodes and the second pair of electrodes are alternately arranged.

Description

Charging equipment and dust remover

Technical Field

Embodiments of the present disclosure relate to a charging apparatus and a dust remover.

Background

Both the air cleaner and the air conditioner are equipped with a dust remover that charges suspended particles by using electric discharge.

The dust collector includes a charger that charges suspended particles by electric discharge and a dust collector that collects the charged suspended particles. As for the charger of the dust collector, a high voltage of several kV is applied to generate a discharge between a high-voltage (discharge) electrode and a counter electrode (ground electrode). When the discharge current flowing between the high voltage electrode and the counter electrode becomes large to obtain high dust collecting efficiency, ozone is easily generated according to the discharge (O3). Ozone has a unique odor, and therefore, when ozone is discharged into a room, ozone levels below environmental standards (50ppb) are required.

Japanese unexamined patent application publication No. 6-182255 (hereinafter referred to as patent document 1) discloses an electrostatic precipitator provided with an ionization section and a dust collector. The ionization part has a discharge line arranged in a direction substantially perpendicular to the direction of the gas flow and a ground electrode formed in a shape for transmitting the gas flow, the ground electrode being arranged at a position that allows a space having the discharge line to be a charged space having a uniform electric field intensity. The dust collector is disposed on a downstream side of the ionization part in the air flow.

International publication No. 2011/034326 (hereinafter, patent document 2) discloses a dust collector provided with a support frame provided with an outer frame defining a hollow through portion, an emitter electrode portion detachably provided within the outer frame of the support frame and including a connection member crossing the through portion and having a plurality of rod electrodes connected to the through portion, and a collector electrode portion detachably disposed within the outer frame of the support frame and including a metal plate electrode installed to face the arranged rod electrodes and defining a plurality of perforations, thereby forming an ion wind of ambient air and collecting suspended matter from the air.

Japanese patent application publication No. 2010-22999 (hereinafter referred to as patent document 3) discloses a charging device for an electrostatic precipitator, wherein the charging device is provided with a charger that charges dust in the air by generating corona discharge between a discharge electrode and a counter electrode opposed to the discharge electrode, and the discharge electrode is plate-shaped and arranged at a distance between the counter electrodes, and a voltage is applied according to the distance.

Disclosure of Invention

Technical problem

When the dust collector is continuously operated for a long time, it is required to suppress the generation of ozone to prevent pungent odor, unpleasant feeling, and pain of nose and throat while still maintaining high dust collecting efficiency. Therefore, there is a need to improve the charging efficiency of suspended particles in a charger of a dust collector without increasing a discharge current.

An aspect of the present disclosure is to provide a charging apparatus capable of improving the charging efficiency of suspended particles while suppressing the concentration of ozone generated.

Technical scheme

According to an aspect of the present disclosure, a charging apparatus includes: a plurality of counter electrodes formed in a plate shape and arranged in a direction crossing a ventilation direction to allow respective surfaces of the plurality of counter electrodes to follow the ventilation direction; and a plurality of high voltage electrodes formed in a line shape and installed between the plurality of counter electrodes. The plurality of counter electrodes includes a first counter electrode having a first electrode area and a second counter electrode having a second electrode area smaller than the first electrode area. The first pair of electrodes and the second pair of electrodes are alternately arranged.

The second pair of electrodes may comprise through holes.

The second pair of electrodes may be arranged such that the degree of opening is higher on the leeward side than on the windward side.

The second pair of electrodes may be disposed such that the center of gravity of the through-hole is located further to the wind side than the high voltage electrode.

The second pair of electrodes may be formed in a plate shape such that a width of the second pair of electrodes is narrower than that of the first pair of electrodes in the ventilation direction.

The second pair of electrodes may be arranged such that the distance between the end of the windward side and the end of the windward side of the first pair of electrodes is smaller than the distance between the end of the leeward side and the leeward side of the first pair of electrodes.

A ratio of the second electrode area to the first electrode area may be greater than 50% and less than 90%.

When the planar shape of the through-hole is a circle, the diameter may be equal to or greater than 2.5% and equal to or less than 60% of the width of the second pair of electrodes in the ventilation direction.

The high voltage electrode may be disposed at the center or windward side of the ventilation direction of the first pair of electrodes.

The hv electrode may have a circular cross-section with a diameter equal to or greater than 20 μm and equal to or less than 300 μm.

The hv electrode may comprise a rectangular corner with an arc-shaped cross-section.

The high voltage electrode may have an arc-shaped corner having a radius of curvature of 5% or more and 50% or less of the length of the short side of the cross-section.

The high voltage electrode may be disposed such that a short side of the cross section is 50 μm or more and 100 μm or less.

The high voltage electrode may be disposed such that a ratio of a length of a long side thereof to a length of a short side thereof exceeds 1 and is equal to or less than 4.

The high voltage electrode may include one of a metal having any one of tungsten, copper, nickel, stainless steel, zinc, and iron, an oxide or an alloy containing the metal as a main component, and a material formed by plating a noble metal such as silver, gold, or platinum on a surface of the metal or the oxide containing the metal as a main component.

According to an aspect of the present disclosure, a charging apparatus includes: a plurality of counter electrodes formed in a plate shape and arranged in a direction crossing a ventilation direction to allow respective surfaces of the plurality of counter electrodes to follow the ventilation direction; and a plurality of high voltage electrodes formed in a line shape and installed between the plurality of counter electrodes. The hv electrode comprises a rectangular corner with an arc-shaped cross-section.

The high voltage electrode may have an arc-shaped corner with a radius of curvature of more than 5% and less than 50% of the length of the short side of the cross-section.

According to one aspect of the present disclosure, a dust collector includes: a charger including a charging device; and a dust collector or a dust collection filter disposed on a leeward side of the charger and configured to collect charged suspended particles floating in an air flow passing through the charger.

The dust collector may include: a high voltage electrode formed in a plate shape and coated with a film formed of an insulating material; and a counter electrode formed in a plate shape having conductivity, and the high voltage electrode and the counter electrode may be alternately stacked.

The dust collecting filter may be electret treated.

Advantageous effects

As is apparent from the above description, according to the charging device and the dust remover, the charging efficiency of the suspended particles can be improved while suppressing the concentration of the generated ozone.

Drawings

Fig. 1 shows a diagram of an example of a precipitator according to a first embodiment;

fig. 2A shows a perspective view of the charger of example 1;

fig. 2B shows a sectional view (sectional view in the Y direction) of the charger of example 1;

fig. 2C and 2D show side views of the counter electrode of example 1;

fig. 3A shows a perspective view of the charger of comparative example 1;

fig. 3B shows a cross-sectional view (cross-sectional view in the Y direction) of the charger of comparative example 1;

fig. 4 is a table showing dust collecting efficiency and ozone concentration at each discharge current of the dust collector having the charger and the counter electrode of the charger in example 1, comparative example 1, other examples, and comparative examples;

5A, 5B, 5C and 5D show side views of different counter electrodes of other examples;

fig. 6A is a graph showing the discharge current dependence of the dust collection efficiency in example 1, example 5, and comparative example 1 and comparative example 2;

fig. 6B is a graph showing the relationship between the dust collection efficiency and the ozone concentration in example 1, example 5, and comparative example 1 and comparative example 2;

fig. 7 is a graph showing a relationship between an aperture ratio (ratio) and a dust collection efficiency at each discharge current in example 1, example 2 and example 3, and comparative example 1, in which counter electrodes having apertures are arranged (provided) in an alternating arrangement in example 1, example 2 and example 3;

fig. 8 is a graph showing a relationship between an opening ratio (ratio) and a dust collection efficiency at each discharge current in example 1, example 4, example 5, and example 6, and comparative example 1, in which counter electrodes having openings including through-holes having different diameters are arranged (set) in an alternating arrangement in example 1, example 4, example 5, and example 6;

fig. 9 is a table showing dust collecting efficiency and ozone concentration at each discharge current of the dust collectors having the chargers and the counter electrodes of the chargers in comparative example 1, comparative example 4, and comparative example 5;

fig. 10A shows a side view of the counter electrode in comparative example 4;

fig. 10B shows a side view of the counter electrode in comparative example 5;

fig. 11 is a graph showing the relationship between the aperture ratio (ratio) and the dust collection efficiency at each discharge current in comparative example 4, comparative example 5, and comparative example 1, in which the counter electrodes having the apertures provided upstream are arranged in an alternating arrangement in comparative example 4 and comparative example 5;

fig. 12 is a graph showing a relationship between the number of ions and the discharge current measured in the chargers in examples 1 and 3 and comparative example 1;

fig. 13 shows a diagram of an example of a dust separator according to a second embodiment;

fig. 14A shows a perspective view of the charger of example 8;

fig. 14B shows a sectional view (sectional view in the Y direction) of the charger of example 8;

fig. 14C shows a cross-sectional view of the high electrode of example 8;

fig. 15 is a table showing dust collecting efficiency and ozone concentration at each discharge current of dust collectors having the charger and the high electrode and the counter electrode of the charger in example 8, comparative example 1, other examples, and comparative examples;

fig. 16A shows a diagram of the charger of example 9;

fig. 16B shows a diagram of a charger of comparative example 6;

fig. 16C shows a diagram of a charger of comparative example 7;

fig. 17A is a graph showing the discharge current dependence of the dust collection efficiency in example 8, example 9 and comparative example 1;

fig. 17B is a graph showing the relationship between the dust collection efficiency and the ozone concentration in example 8, example 9, and comparative example 1;

fig. 18A is a graph showing the discharge current dependence of the dust collection efficiency in example 8, comparative example 1, comparative example 6, and comparative example 7;

fig. 18B is a graph showing the relationship between the dust collecting efficiency and the ozone concentration in example 8, comparative example 1, comparative example 6, and comparative example 7; and

fig. 19 shows a diagram of an example of a dust collector according to the third embodiment.

Detailed Description

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[ first embodiment ]

Fig. 1 shows a diagram of an example of a precipitator 1 according to a first embodiment.

The dust collector 1 to which the first embodiment is applied includes a charger 10, a dust collector 20, and a fan 30, and a housing 40 that accommodates the charger 10, the dust collector 20, and the fan 30. The housing 40 is shown by broken lines in order to show the configuration of the charger 10 and the dust collector 20 disposed inside the housing 40. The dust collector 1 is a two-stage electrostatic dust collecting system in which functions of a charger 10 and a dust collector 20 are separated. The charger 10 and the dust collector 20 may be configured as a detachable unit type.

The dust collector 1 further includes a power supply supplying a high voltage to the charger 10 and the dust collector 20, and a controller controlling the charger 10, the dust collector 20, the fan 30, and the power supply, but a description of the power supply and the controller will be omitted. Further, the charger 10 included in the dust remover 1 to which the first embodiment is applied is an example of a charging apparatus.

As shown by the arrow, the airflow (ventilation) direction (ventilation direction) is set to a direction from the charger 10 toward the dust collector 20 (from the left side toward the right side with respect to the floor of fig. 1, and a Z direction described later). The ventilation is performed by the fan 30 disposed at the downstream side (leeward side) of the ventilation direction of the dust collector 20.

(charger 10)

The charger 10 is provided with a plurality of high-voltage electrodes 110 and a plurality of counter electrodes 120 respectively facing the plurality of high-voltage electrodes 110. The high voltage electrode 110 denotes an electrode to which a high voltage is applied, and is therefore referred to as a "high voltage electrode". The high voltage electrode 110 is an electrode that generates a discharge, and is therefore referred to as a "discharge electrode". Since there is a case where the counter electrode 120 is Grounded (GND), the counter electrode 120 may be referred to as a "ground electrode".

The high voltage electrode 110 is formed of a linear member having conductivity.

The counter electrode 120 is formed of a plate-like member having conductivity. The counter electrode 120 is mounted such that the plane of the plate-like member is along the ventilation direction. Fig. 1 shows that the plane of the counter electrode 120 is aligned with the ventilation direction (i.e., the angle between the plane of the counter electrode 120 and the ventilation direction is zero), but is not limited thereto. Therefore, an angle of less than 90 ° between the plane of the counter electrode 120 and the ventilation direction is suitable.

The counter electrode 120 has a different shape with respect to the single sheet. That is, the even-numbered counter electrodes 120 in the X direction have the openings 130, and the area of the portion serving as an electrode (hereinafter referred to as "electrode area") is smaller than that of the odd-numbered counter electrodes 120. In other words, the counter electrodes 120 having different electrode areas are alternately arranged in a direction crossing the ventilation direction.

Hereinafter, the charger 10 will be described as example 1.

In the charger 10 of example 1, the odd-numbered counter electrode 120 refers to the counter electrode 120A (referred to as "a" in some cases), and the even-numbered counter electrode 120 refers to the counter electrode 120B (referred to as "B" in some cases). For the counter electrode 120B, the opening 130 is constituted by a through hole 131 described later. Since the counter electrode 120B is provided with the through hole 131, the electrode area of the counter electrode 120B is smaller than that of the counter electrode 120A.

The high voltage electrodes 110 are indicated by "". Thus, with the dust remover 1 of fig. 1, in the charger 10 of example 1, the high voltage electrode 110 and the counter electrode 120 are arranged as a-x-B-a. An arrangement in which the counter electrodes 120 having different electrode areas are alternately arranged is referred to as an "alternate arrangement", and an arrangement in which the counter electrodes 120 having the same electrode area are arranged is referred to as a "homogeneous arrangement".

(dust collector 20)

The dust collector 20 is provided with a high voltage electrode 210 and a counter electrode 220, the high voltage electrode 210 being formed in a plate shape and coated with a film formed of an insulating material, the counter electrode 220 being formed in a plate shape having conductivity, wherein the high voltage electrode 210 and the counter electrode 220 are alternately stacked. In addition, it is suitable that the counter electrode 220 has a shape capable of discharging charges of the charged particles and that the counter electrode 220 is coated with a resin film having conductivity. The space between the high voltage electrode 210 and the counter electrode 220 becomes a ventilation direction. In addition, since the counter electrode 220 is Grounded (GND), the counter electrode 220 may be referred to as a "ground electrode".

A high voltage of Direct Current (DC) is applied between the high voltage electrode 210 and the counter electrode 220 by a high voltage (not shown). The suspended particles charged in the charger 10 adhere to the surface of the counter electrode 220 by static electricity. Thus, the suspended particles are collected.

The film formed of an insulating material covering the surface of the high voltage electrode 210 may include polyethylene, polyethylene terephthalate (PET), and Polytetrafluoroethylene (PTFE).

(case 40)

In the housing 40, an inlet 41 is mounted on a side of the charger 10 on an upstream side (windward side) in the ventilation direction, and an outlet 42 is mounted on a side of the dust collector 20 on a leeward side. Further, a mesh and a grill may be installed in the inlet 41. The mesh and grill installed in the inlet 41 may prevent a user from contacting the charger 10 and reduce resistance against ventilation. In the inlet 41, a pre-filter may be installed to prevent large-shaped particles from being introduced.

The fan 30 is mounted in the outlet 42, and the outlet 42 is mounted in the housing 40 and disposed on the leeward side.

That is, the airflow (ventilation) enters an inlet 41 in the side of the charger 10 of the housing 40, passes through the charger 10 and the dust collector 20, and then exits from an outlet 42 of the housing 40 where the fan 30 is mounted. For convenience of description, as shown in fig. 1, the ventilation direction is set to a Z direction, and a direction perpendicular to the Z direction is set to an X direction and a Y direction.

Furthermore, the dust separator 1 may be placed in any direction as long as ventilation is not blocked.

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

A high voltage of Direct Current (DC) is applied between the high voltage electrode 110 and the counter electrode 120 by a high voltage (not shown). Accordingly, corona discharge occurs between the high voltage electrode 110 and the counter electrode 120. Ions generated by the corona discharge adhere to the aerosol, thereby charging the aerosol.

(example 1)

Fig. 2A to 2D show diagrams of the charger 10 of example 1 in detail. Fig. 2A shows a perspective view of the charger 10 of example 1, fig. 2B shows a cross-sectional view (a cross-sectional view in the Y direction) of the charger 10, fig. 2C shows a side view of the counter electrode 120A, and fig. 2D shows a side view of the counter electrode 120B.

The charger 10 of example 1 is provided with the high-voltage electrode 110 and the counter electrodes 120A and 120B having different electrode areas.

As shown in fig. 2A and 2B, the high voltage electrode 110 is formed of a tungsten wire (W) having a diameter of 90 μm. That is, the cross-section of the high voltage electrode 110 is circular. The high voltage electrode 110 may be a metal such as copper, nickel, stainless steel, zinc, iron, or an alloy containing a metal as a main component, in addition to tungsten. In addition, the high voltage electrode 110 may be formed by plating a noble metal (such as silver, gold, or platinum) on the surface of a metal or an alloy or an oxide containing the metal as a main component. In addition, if the high voltage electrode 110 is formed of tungsten oxide, the high voltage electrode 110 may be stable. The diameter of the high voltage electrode 110 may be equal to or greater than 20 μm and equal to or less than 300 μm.

The counter electrode 120A has a plate shape without the opening 130. On the other hand, the counter electrode 120B has an opening 130, and the opening 130 is provided with a through hole 131. The counter electrode 120A without the through-hole 131 and the counter electrode 120B with the through-hole 131 are arranged (provided) in an alternating arrangement. As described above, the counter electrode 120A and the counter electrode 120B are arranged as a- × -B- × -a- × -B- × a. This is simply indicated by "AB". Other examples will be described in the same manner.

In addition, the openings 130 refer to all the through holes 131 on the counter electrode 120B. For convenience of description, fig. 1 and 2D illustrate the opening 130 surrounding the through-hole 131.

For example, the counter electrodes 120A and 120B are formed of aluminum. The counter electrode 120 may be formed of metal such as stainless steel (SUS) and nickel alloy or carbon, in addition to aluminum.

For example, the widths (WA and WB) of the counter electrodes 120A and 120B corresponding to the Z-direction length are 10 mm. Alternatively, the widths (WA and WB) may be less than 10mm or greater than 10 mm. However, as the widths (WA and WB) are reduced, the size of the charger 10 may be reduced. The length (Y-direction length) of the counter electrode 120 may be selected based on the size of the dust remover 1. For example, the length (Y-direction length) is 400 mm.

As shown in fig. 2C, the counter electrode 120A has a plate shape without the opening 130. Meanwhile, as shown in fig. 2D, the counter electrode 120B has an opening 130. A plurality of through holes 131 arranged in the Y direction are mounted in rows in the opening 130. The planar shape of the through-hole 131 is circular. For example, the diameter (dB) of the through hole 131 is

The planar shape of the through-hole 131 may have various shapes such as an ellipse or a quadrangle in addition to a circle. The through-hole 131 may have a shape preventing concentration of an electric field.

The counter electrodes 120A and 120B have the same outer shape. Therefore, the ratio between the area of all the through holes 131 (openings 130) of the counter electrode 120 and the outer surface area of the counter electrode is indicated by the aperture ratio or simply by the ratio. That is, when the through hole 131 is not provided, the opening ratio (ratio) of the counter electrode 120A is 0%. On the other hand, the counter electrode 120B has an aperture ratio (ratio) obtained by the area of the through hole 131. In example 1, the aperture ratio (ratio) of the counter electrode 120B was 13.8%.

As shown in fig. 2B, the high voltage electrode 110 is installed on the windward side (Z direction side) with respect to the width direction (Z direction) of the counter electrode 120. The high voltage electrode 110 is installed at a Distance (DF) from the windward end and a Distance (DB) from the leeward end in the width direction of the counter electrode 120. DF + DB ═ WA or WB. For example, DF: DB is 3: 7. However, the position of the high voltage electrode 110 is not limited thereto, and thus the high voltage electrode 110 may be installed in another position. As described above, the reason why the high voltage electrode 110 is installed outside the windward side of the high voltage electrode 110 with respect to the width direction of the counter electrode 120 will be described later.

For example, the Distance (DG) between the high voltage electrode 110 and the counter electrodes 120A and 120B is 10 mm.

Comparative example 1

Fig. 3A and 3B show diagrams of the charger 10 of comparative example 1. Fig. 3A shows a perspective view of the charger 10, and fig. 3B shows a sectional view (a sectional view in the Y direction) of the charger 10. In comparative example 1, all the counter electrodes 120 correspond to the counter electrode 120A shown in fig. 2C. That is, the charger 10 of comparative example 1 shown in fig. 3A corresponds to a configuration in which the counter electrode 120A ("a") replaces the counter electrode 120B ("B") of example 2 of fig. 2A. That is, counter electrode 120 is arranged in a homogenous arrangement of a-. This is simply indicated by AA.

Fig. 4 is a table showing dust collection efficiency and ozone concentration at each discharge current in example 1, comparative example 1, other examples, and comparative example. The dust collecting efficiency and the ozone concentration were measured at different discharge currents of the charger 10. The high voltage electrode 110 is formed of a tungsten wire having a diameter of 90 μm (circular cross section). The voltage between the high voltage electrode 210 and the counter electrode 220 of the dust container 20 was 6 kV. Further, the wind speed in the ventilation direction is set to 1 m/s. The discharge currents were set at 150 μ A, 250 μ A and 450 μ A.

The dust collection efficiency (%) is measured by counting the number of suspended particles using a particle counter before entering the upstream side (charger 10) in the ventilation direction of the dust collector 1 and after being discharged from the downstream side (dust collector 20). In addition, the ozone concentration (ppb) is measured at the downstream side (after being discharged from the dust collector 20) in the ventilation direction of the dust collector 1 by using an ozone meter.

As described above, with the charger 10 of example 1, the counter electrodes 120 are arranged in the alternating Arrangement (AB), whereas with the comparative example 1, the counter electrodes 120 are arranged in the homogeneous arrangement (AA).

In other examples 2 to 7, the counter electrodes 120 of the charger 10 are arranged in such a manner that example 2 is an AC type alternating arrangement, example 3 is an AD type alternating arrangement, example 4 is an AE type alternating arrangement, example 5 is an AF type alternating arrangement, example 6 is an AG type alternating arrangement, and example 7 is an AH type alternating arrangement. That is, according to examples 1 to 7, the counter electrode 120 has an alternate arrangement (disposition) of different shapes (different electrode areas).

The counter electrodes 120C, 120D, 120E, 120F, 120G, and 120H in examples 2 to 7 are explained below.

Fig. 5A to 5D show side views of the other counter electrodes 120C, 120D, 120E, 120F, 120G, and 120H. Fig. 5A shows the counter electrode 120C, fig. 5B shows the counter electrode 120D, fig. 5C shows the counter electrodes 120E, 120F, and 120G, and fig. 5D shows the counter electrode 120H.

In the counter electrode 120C shown in FIG. 5A, the diameter is

Are arranged in two rows in a zigzag pattern in the Y direction. Therefore, the through-hole 131 is provided on the entire surface of the counter electrode 120C. In this case, the aperture ratio was 27.6%.

In the counter electrode 120D shown in fig. 5B, the counter electrode 120D is constituted by a cut-out portion 132 attached to the leeward side (Z direction). That is, the counter electrode 120D is configured such that a part of the counter electrode 120A is cut away. In other words, the windward end of the counter electrode 120D is at the same position with respect to the windward end of the counter electrode 120A and the Z direction (on the Z axis). The leeward-side end of the counter electrode 120D is placed at a short position (a position having a small coordinate value) with respect to the leeward-side end of the counter electrode 120D and the Z direction (on the Z axis).

The depth (dw) of the cut-out portion 132 is set to 5 mm. Therefore, the aperture ratio was 50%.

In addition, the counter electrode 120D may be formed of a metal having a width obtained by subtracting the depth (dw) of the cut-out portion 132 from the Width (WB). That is, the width of the counter electrode 120D in the ventilation direction may be narrower than the width of the counter electrode 120A in the ventilation direction.

Further, the aperture ratio is set by adjusting the depth (dw).

In the counter electrodes 120E, 120F, and 120G shown in fig. 5C, a plurality of through holes 131 having a diameter (dB) are provided on the entire surface of the counter electrode 120 as in the counter electrode 120C of fig. 5A. Diameter (dB) of

Is mounted in the counter electrode 120E. The aperture ratio of the counter electrode 120E was 10%. Diameter (dB) of

Is provided with a through hole 131Is housed in the counter electrode 120F. The aperture ratio of the counter electrode 120F was 36%. Diameter (dB) of

Is mounted in the counter electrode 120G. The aperture ratio of the counter electrode 120G was 50%.

Further, in the counter electrode 120H shown in FIG. 5D, the diameter (dB) is

Is installed on the leeward side in the same arrangement as the counter electrode 120B of fig. 2A and 2D.

In other comparative examples 2 and 3 shown in fig. 4, the counter electrode 120 of the charger 10 is configured in such a manner that the comparative example 2 is a BB type homogeneous arrangement and the comparative example 3 is a CC type homogeneous arrangement. That is, according to comparative examples 1 to 3, the counter electrodes 120 having the same shape (the same electrode area) are arranged in a homogenous arrangement. In addition, the counter electrode 120B is shown in fig. 2D, and the counter electrode 120C is shown in fig. 5A.

A prominent example will be described below based on the results of fig. 4. Fig. 6A and 6B are graphs showing the discharge current dependency of the dust collection efficiency and the relationship between the dust collection efficiency and the ozone concentration in example 1(AB), example 5(AF), and comparative example 1(AA) and comparative example 2 (BB). Fig. 6A shows the discharge current dependence of the dust collection efficiency, and fig. 6B shows the relationship between the dust collection efficiency and the ozone concentration. In fig. 6A, the horizontal axis represents the discharge current (μ a) and the vertical axis represents the dust collection efficiency (%). In fig. 6B, the horizontal axis represents the ozone concentration (ppb) and the vertical axis represents the dust collection efficiency (%).

In comparative example 1(AA) of fig. 6A, the dust collecting efficiency increased with the discharge current. However, if the discharge current is not 450 μ A, the dust collecting efficiency is less than 99%.

In comparative example 2(BB), the dust collecting efficiency was higher than that of comparative example 1(AA) in the case where the discharge current was in the low range. However, as in comparative example 1(AA), if the discharge current is not 450. mu.A, the dust collecting efficiency is less than 99%.

That is, as shown in comparative example 2(BB), when the counter electrode 120B in which the openings 130 (through holes 131) are installed on the leeward side is arranged in a homogenous arrangement, the dust collection efficiency is more likely to be improved in the case where the discharge current is in a low range. But the effect is small.

On the other hand, in examples 1(AB) and 5(AF) in which the counter electrodes 120 having different aperture ratios (ratios) are arranged (set) in an alternating arrangement, dust collection efficiency is more likely to be improved in the case where the discharge current is in a low range, as compared with comparative examples 1(AA) and 2 (BB). In particular, in example 1(AB), although the discharge current was 150 μ a, a dust collection efficiency of 98.88% was obtained.

Based on example 1(AB) and comparative example 2(BB), it was observed that although the opening 130 (through hole 131) was installed in the counter electrode 120B on the leeward side to be arranged in the homogeneous arrangement used in example 1(AB), no greater improvement in dust collection efficiency was expected in the low range of 300 μ a or less. Based on example 1(AB) and example 5(AF) using the alternate arrangement, it was observed that example 1(AB) of the counter electrode 120B mounted on the leeward side using the opening 130 (through hole 131) had improved dust collection efficiency even at a low discharge current of 150 μ a, as compared with example 5(AF) in which the opening 130 (through hole 131) was mounted on the entire surface.

That is, it is observed that since the openings 130 (through holes 131) are installed in the counter electrode 120B on the leeward side and the counter electrode 120A without the openings 130 are arranged in the charger 10 in an alternating arrangement, the dust collection efficiency is improved in the low range (150 μ a) of the discharge current. This indicates that the charge efficiency of the suspended particles is improved at a low range of discharge current (150 μ a).

Based on the relationship between the dust collecting efficiency and the ozone concentration shown in fig. 6B, it was observed that according to example 1(AB) and example 5(AF) having an alternate arrangement, high dust collecting efficiency was obtained while the ozone concentration was kept at a low level. This is because high dust collection efficiency can be obtained with a low discharge current in example 1(AB) and example 5(AF), which is shown in the discharge current dependence of the dust collection efficiency shown in fig. 6A. In contrast, as shown by the discharge current dependency of the dust collection efficiency shown in fig. 6A, it is necessary to increase the discharge current to obtain high dust collection efficiency, and therefore the ozone concentration increases. That is, according to example 1(AB) and example 5(AF), it was possible to obtain a dust collecting efficiency of 95% or more in the range where the ozone concentration was 4.0ppb or less (significantly lower than the environmental standard value (50 ppb)).

Fig. 7 is a graph showing a relationship between an opening ratio (ratio) at each discharge current and dust collection efficiency in examples 1, 2, and 3, and comparative example 1, in which counter electrodes having openings 130 are arranged in an alternating arrangement in examples 1, 2, and 3. The horizontal axis represents the ratio (%), and the vertical axis represents the dust collection efficiency (%). The discharge currents were set at 150 μ A, 250 μ A, and 450 μ A.

The ratio of comparative example 1(AA) was 0%. The counter electrode 120B of example 1(AB) is disposed such that

Is provided in the leeward side opening 130, the ratio of the counter electrode 120B is 13.8%. Counter electrode 120C of example 2(AC) was set so that

Is provided on the entire surface, and the ratio of the through-holes 131 is 27.6%. The counter electrode 120D of example 3(AD) is provided with the cut-out portion 132 on the leeward side, and the ratio of the counter electrode 120D is 50%.

As shown in fig. 7, it was observed that example 1(AB), example 2(AC), and example 3(AD) in which the counter electrodes 120 having the openings 130 were arranged in an alternating arrangement had high dust collection efficiency at a low discharge current (e.g., 150 μ a) as compared to comparative example 1(AA) in which the openings 130 were not provided. In this regard, when the aperture ratio (ratio) is 10% or more and 50% or less, the dust collection efficiency is improved at a low discharge current (e.g., 150 μ a). However, based on the fact that example 1(AB) at a ratio of 13.8% and example 3(AD) at a ratio of 50% have high dust collection efficiency at a low discharge current, it was observed that the dust collection efficiency was not always improved in spite of the increase in the opening ratio (ratio), as compared with example 2(AC) at a ratio of 27.6%. It is observed that it is appropriate that the opening 130 (through hole 131) or the cut-out portion 132 is installed on the leeward side. For the openings 130, when the ratio of the through holes 131 per unit area is referred to as "opening degree", it is observed that the opening degree on the leeward side is higher than the opening degree on the windward side. That is, the through-holes 131 may be installed such that the opening degree increases from the windward side to the leeward side. For example, the through holes 131 may be disposed such that the diameter (dB) increases from the windward side to the leeward side at predetermined intervals, or the number of the through holes 131 increases from the windward side to the leeward side.

In addition, for the counter electrode 120D having the opening 130 of a narrow width caused by the cutout portion 132, the distance between the end of the counter electrode 120D on the windward side and the end of the counter electrode 120A on the windward side may be smaller than the distance between the end of the counter electrode 120D on the leeward side and the end of the counter electrode 120A on the leeward side.

Fig. 8 is a graph showing a relationship between an opening ratio (ratio) and a dust collection efficiency at each discharge current in example 1, example 4, example 5, and example 6, and comparative example 1, in which counter electrodes having openings including through holes having different diameters (dB) are arranged in an alternating arrangement in example 1, example 4, example 5, and example 6. The horizontal axis represents the ratio (%), and the vertical axis represents the dust collection efficiency (%). The discharge currents were set at 150 μ A, 250 μ A, and 450 μ A.

Comparative example 1(AA) does not have the through-hole 131, and thus the ratio thereof is 0%. The counter electrode 120E of example 4(AE) was provided such that the through-hole 131 having a diameter (dB) of 0.25mm was arranged on the inner surface, and the ratio of the counter electrode 120E was 10%. The counter electrode 120B of example 1(AB) was disposed such that the through-hole 131 having a diameter (dB) of 3mm was disposed on the leeward side, and the ratio of the counter electrode 120B was 13.8%. An example of a ratio indicating 18%, not shown in fig. 4, is provided such that a through hole 131 having a diameter (dB) of 0.5mm is provided on the entrance surface. The counter electrode 120F of example 5(AF) was disposed such that the through-hole 131 having a diameter (dB) of 0.75mm was disposed on the entrance surface, and the ratio of the counter electrode 120F was 36%. The counter electrode 120D of example 6(AD) was disposed such that the through-hole 131 having a diameter (dB) of 1.5mm was disposed on the entrance surface, and the ratio of the counter electrode 120D was 50%. Example 1(AB), example 4(AE), example 5(AF), example 6(AD), and the case with the 18% ratio have an alternate arrangement.

At a high discharge current (450 μ a), no significant difference caused by the diameter (dB) of the via 131 is shown. However, at low discharge currents (150 μ A and 250 μ A), the dust collecting efficiency is improved as the diameter (dB) of the through-hole 131 is increased. However,

example 1(AB) in which the through-holes 131 are disposed at the leeward side has the highest dust collecting efficiency.

It was observed that the dust collecting efficiency was improved in the case of example 1(AB), example 4(AE), example 5(AF), example 6(AD) and the ratio was 18% as compared with comparative example 1 (AA). Based on this result and the result of example 7, it was observed that the diameter (dB) of the through-hole 131 of the opening 130 indicating the improved dust collection efficiency was equal to or greater than 2.5% and equal to or less than 60% with respect to the Width (WB) of the ventilation direction of the counter electrode 120. Further, the opening ratio that enables improvement of dust collecting efficiency is equal to or more than 10% and equal to or less than 50%.

Therefore, in the case of the counter electrode 120D in which the cutout 132 is provided to the opening 130, the depth (dw) of the cutout 132 may be 10% or more and 50% or less of the Width (WB) of the counter electrode 120D. That is, the ratio of the electrode area of the counter electrode 120D to the counter electrode 120A may be set to be more than 50% and less than 90%.

The case where the counter electrodes 120 in which the openings 130 are provided on the leeward side are arranged (provided) in an alternately arranged manner (such as example 1(AB), example 3(AD), and example 7(AH)) and the case where the counter electrodes 120 in which the openings 130 are arranged over the entire surface are arranged (provided) in an alternately arranged manner (such as example 2(AC), example 4(AE), example 5(AF), and example 6(AG)) have been described above.

Hereinafter, a case where the counter electrodes 120 in which the openings 130 are provided on the windward side are arranged (provided) in an alternating arrangement will be described.

Fig. 9 is a table showing dust collecting efficiency and ozone concentration at each discharge current of the dust collectors having the charger 10 and the counter electrode of the charger 10 in comparative example 1, comparative example 4, and comparative example 5. As described above, comparative example 1 is such that the counter electrode 120 is arranged in an AA-type homogeneous arrangement. In addition, comparative example 4 is an AB 'type alternate arrangement, and comparative example 5 is an AD' type alternate arrangement. The discharge currents were set at 150 μ A, 250 μ A, and 450 μ A.

The counter electrodes 120B 'and 120D' of comparative examples 4 and 5 will be described below.

Fig. 10A and 10B are side views showing counter electrodes 120B 'and 120D' of comparative examples 4 and 5. Fig. 10A shows a counter electrode 120B 'according to comparative example 4, and fig. 10B shows a counter electrode 120D' according to comparative example 5.

The counter electrode 120B' of FIG. 10A is set so that the diameter (dB) is

Are aligned in the Y direction on the lee side. That is, the counter electrode 120B' has a configuration in which the windward side and the leeward side of the counter electrode 120D shown in fig. 2D are switched with each other. In this case, the ratio of the counter electrode 120B' is 13.8%.

The counter electrode 120D 'of fig. 10B is arranged such that the opening 130 is configured by a cut-out portion 132' installed on the leeward side. That is, the counter electrode 120D' has a configuration in which the windward side and the leeward side of the counter electrode 120D are switched with each other as shown in fig. 5D. In this case, the ratio of the counter electrode 120D' is 50%.

In addition, the aperture ratio of comparative example 1(AA) was 0%.

Fig. 11 is a graph showing the relationship between the opening ratio (ratio) at each discharge current and the dust collection efficiency in comparative example 4(AB '), comparative example 5 (AD'), and comparative example 1(AA), in which the counter electrodes having the openings arranged (provided) upstream are arranged in an alternating arrangement in comparative example 44(AB ') and comparative example 5 (AD'). The horizontal axis represents the ratio (%), and the vertical axis represents the dust collection efficiency (%). The discharge currents were set at 150 μ A, 250 μ A, and 450 μ A.

In fig. 11, it is observed that, although the opening 130 (through hole 131) and the cut-out portion 132 are installed on the windward side as shown in comparative example 4(AB ') and comparative example 5 (AD'), the discharge current is not followed and the dust collecting efficiency is not improved, as compared with comparative example 1 without the opening 130. This is because the counter electrode 120 does not exist at a portion facing the high voltage electrode 110, and an electric field is hardly applied to the portion.

That is, it can be seen that it is appropriate to provide the opening 130 on the leeward side. When the opening 130 is constituted by the through hole 131, it is appropriate that the center of gravity of the through hole 131 is located on the leeward side of the high voltage electrode 110. The center of gravity of the through-hole 131 does not refer to the hole of the through-hole 131, but refers to the center of gravity of the plate-like member. When the planar shape of the through-hole 131 is a circle, the center of gravity of the through-hole 131 becomes the center of the through-hole 131.

(measurement of ion number)

The improvement in dust collecting efficiency at a low discharge current (such as 150 μ a) is considered to be due to an increase in the number of ions (number of ions) generated at a low discharge current. That is, it is considered that the improvement of the dust collection efficiency is due to the increase of the number of generated ions, and therefore, the number of suspended particles to which ions are attached is increased, and the dust collection efficiency is improved.

To confirm this, the number of generated ions (ion number) generated from the charger 10 was measured in example 1(AB), example 3(AD), and comparative example 1 (AA). In example 1(AB) and example 3(AD), the counter electrodes 120 in which the openings 130 are arranged on the leeward side are arranged in an alternating arrangement. Comparative example 1(AA) is a case where the counter electrode 120 having no opening 130 is arranged in a homogenous arrangement.

The number of ions generated from the charger 10 was measured without providing the dust collector 20 in the dust collector 1. The number of ions generated in the charger 10 was measured by an ion counter provided at a position 30cm away from the charger 10 on the leeward side at a wind speed of 1 m/sec.

Fig. 12 is a graph showing the relationship between the number of ions measured in the charger 10 and the discharge current in example 1(AB), example 3(AD), and comparative example 1 (AA). The horizontal axis represents the discharge current (. mu.A), and the vertical axis represents the number of ions (. times.1000 ions/cm 3). The number of ions on the vertical axis is an average of the measured numbers of ions obtained by sampling every 10 seconds for 10 minutes at discharge currents of 150 μ a, 250 μ a, 350 μ a, and 450 μ a.

In fig. 12, it is observed that: the number of ions was more in example 1(AB) and example 3(AD) than in comparative example 1(AA), regardless of the discharge current level. In particular, at low discharge currents (150 μ A and 250 μ A), the difference in ion numbers is large.

Therefore, it can be seen that the number of ions is increased by arranging the counter electrode 120 in which the openings 130 are arranged on the leeward side in an alternating arrangement.

Ions are generated in the discharge space in the immediate vicinity of the high voltage electrode 110. Ions move downstream along the ventilation. At this time, ions are attached to the aerosol, and the aerosol is charged. Therefore, as the amount of ions increases, the number of charged aerosol particles also increases. As the number of charged aerosol increases, dust collecting efficiency is improved.

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 having a diameter of 90 μm. In example 1(AB) and example 3(AD), the opening 130 is provided on the leeward side. That is, the portion of the counter electrode 120 other than the opening 130 faces the vicinity of the high voltage electrode 110. The Distance (DG) between the high voltage electrode 110 and the counter electrode 120 is also equal to 10 mm. Therefore, it is considered that there is no difference in the discharge amount of the discharge generated in the closest 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, the ion numbers measured on the leeward side in example 1(AB), example 3(AD), and comparative example 1(AA) were different. Therefore, some of the ions generated at the high voltage electrode 110 are considered to disappear before reaching the dust collector 20. That is, it is considered that the ions are electrostatically attracted and then attached to the counter electrode 120 or collide with the counter electrode 120, and thus the charges are lost (neutralized).

In examples 1(AB) and 3(AD) in which the opening 130 is provided on the leeward side, the number of ions measured on the leeward side is large. Therefore, it is considered that the probability of ions attaching to the counter electrode 120 or colliding with the counter electrode 120 is reduced by the opening 130 formed 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), when the counter electrodes 120 are arranged in an alternating arrangement, the dust collection efficiency is improved compared to comparative example 1, although the counter electrodes 120 on which the openings 130 are installed on the entire surface are used.

However, although the counter electrode 120 provided with the opening 130 was used as in comparative example 2(BB) and comparative example 3(CC), when the counter electrode 120 was arranged in a homogenous arrangement, no improvement in dust collection efficiency was observed. In this regard, by arranging the counter electrode 120 having the opening 130 and the counter electrode 120 not having the opening 130 in an alternating arrangement, the ions are difficult to disappear (neutralize). That is, the electric field generated between the adjacent counter electrodes 120 is considered to prevent loss (neutralization) of ions.

Further, the longer the time (residence time) for which ions are present in the charger 10, the higher the probability that the suspended particles are charged. Therefore, it is appropriate to dispose the high voltage electrode 110 on the windward side including the center of the counter electrode 120. In contrast, when the high voltage electrode 110 is offset to the windward side from the windward side end portion of the counter electrode 120, the electric field strength in the vicinity of the high voltage electrode 110 decreases, which is not appropriate.

In addition, when the counter electrode 120 having the opening 130 is used, the reason why the number of ions increases is also considered to be that turbulence of the gas flow is generated and the residence time of the ions increases. However, according to the simulation, the turbulence of the air flow cannot be identified at a flow speed of 1 m/sec.

In particular, at low discharge currents, the number of ions generated is small. However, by suppressing the disappearance (neutralization) of ions having a small amount of generated particles, the charging efficiency of suspended particles can be improved, and the dust collecting efficiency can be improved even at a low discharge current. By reducing the discharge current, the ozone concentration can be suppressed to a low level. That is, high dust collecting efficiency and suppression of ozone concentration can be simultaneously obtained.

[ second embodiment ]

In the first embodiment, by using the configuration of the counter electrode 120, the dust collection efficiency at a low discharge current is improved by suppressing the loss (neutralization) of ions generated in the discharge space around the high voltage electrode 110.

In the second embodiment, a configuration of the high voltage electrode 110 in which the dust collecting efficiency is improved at a low discharge current generating less ozone is provided.

Fig. 13 shows an example of the dust separator 2 according to the second embodiment.

The dust collector 2 to which the second embodiment is applied has the charger 10, the dust collector 20, the fan 30, and the housing 40 that accommodates the charger 10, the dust collector 20, and the fan 30. The dust remover 2 is the same as the dust remover 1 to which the first embodiment is applied, except for the charger 10, and therefore, the same reference numerals are given and the description is omitted. The charger 10 provided in the dust remover 2 to which the second embodiment is applied is another example of a charging apparatus.

(charger 10)

The charger 10 includes a plurality of high voltage electrodes 110 and a plurality of counter electrodes 120 facing the plurality of high voltage electrodes 110, respectively.

The high voltage electrode 111 is formed of a linear member having conductivity. Further, the high voltage electrode 111 has a cross section in which rectangular corner portions have an arc shape. The cross-sectional shape is indicated by an oval or racetrack shape.

The counter electrode 120 is formed of a plate-like member having conductivity. The counter electrode 120 is mounted such that the plane of the plate-like member is along the ventilation direction. In addition, the counter electrodes 120 having the same shape (the same electrode area) are arranged (provided) in a manner of a homogeneous arrangement. In fig. 13, the counter electrode 120 is the counter electrode 120A shown in fig. 2C. The counter electrode 120A is not provided with the opening 130.

(example 8)

Fig. 14A to 14C show views of the charger 10 of example 8. Fig. 14A is a perspective view of the charger 10, fig. 14B is a sectional view (a sectional view in the Y direction) of the charger 10, and fig. 14C is a sectional view of the high electrode 111 of example 8.

As shown in fig. 14C, the elliptical cross section of the high voltage electrode 111 is arranged such that the corners of the square have an arc shape with a radius of curvature (rw). The long side direction of the rectangle is defined as the length of the long side (WW), and the short direction is defined as the length of the short side (TW).

As shown in fig. 14A and 14B, the high voltage electrode 111 is arranged such that the long side direction of the rectangle is arranged in a direction parallel to the surface of the counter electrode 120A. Alternatively, the long side direction of the rectangle of the high voltage electrode 111 may be perpendicular to the surface of the counter electrode 120A.

Corona discharge occurs in portions where the electric field is high. The volume of this portion is called the discharge volume. For the high voltage electrode 110 (refer to fig. 2B) having a line shape of a circular cross section, as the diameter is reduced, the electric field around the high voltage electrode 110 becomes higher, and the discharge volume becomes smaller. Since the electric field is high, the number of generated ions increases, but since the discharge volume is small, the generation of ozone is suppressed.

However, when the diameter (dB) of the high voltage electrode 110 is made small, that is, when the high voltage electrode 110 is made thin, it is difficult to handle the high voltage electrode 110. For example, it is difficult to mount the high voltage electrode 110 formed of tungsten (W) to a predetermined portion. When the high voltage electrode 110 formed of tungsten (W) is bent, it is difficult to change the shape and the discharge characteristics are not uniform. In addition, the high voltage electrode 110 formed of tungsten (W) is also easily bent.

As shown in fig. 14C, in the high-voltage electrode 111 having an elliptical cross section, corona discharge occurs in a portion (α) where the radius of curvature (rw) of the cross section is small. In a portion (β) which is a central portion in the longitudinal direction of the rectangle, corona discharge is less likely to occur. Therefore, by reducing the radius of curvature (rw) of the corners of the cross section, the discharge volume can be reduced, and the generation of ozone can be suppressed while increasing the number of generated ions.

The radius of curvature (rw) of the corner of the cross section of the high-voltage electrode 111 in the charger 10 of example 8 is 1/2 of the length (TW) of the short side. In the high voltage electrode 111, the length (WW) of the long side is 150 μm, and the length (TW) of the short side is 50 μm. Therefore, similarly to the case where the high voltage electrode 110 having a diameter of a circular cross section is divided into two and the space therebetween is opened. That is, similarly, the high voltage electrode 110 having a diameter of 90 μm as described in the first embodiment is changed to a diameter of 50 μm. When the above cross-sectional shape is used, it is difficult to bend or break, and thus it is easy to handle.

Fig. 15 is a table showing dust collection efficiency and ozone concentration at each discharge current of the dust collectors having the charger 10 and the high electrodes 110 and 111 of the charger 10 and the electrodes 120 in example 8, comparative example 1, other examples, and other comparative examples.

Comparative example 1 has been described in the first embodiment. Example 9 and comparative examples 6 and 7 will be described later. The discharge currents were set to 15 μ A, 250 μ A, and 450 μ A.

Fig. 16A to 16C are diagrams illustrating the charger 10 of example 9 and comparative examples 6 and 7. Fig. 16A is example 9, fig. 16B is comparative example 6, and fig. 16C is comparative example 7.

Example 9 is a combination of the elliptical high-voltage electrode 111 shown in example 8 and the counter electrodes 120A and 120B arranged in an alternating arrangement shown in example 1 of the first embodiment.

Comparative example 6 uses a high voltage electrode 112 having a square cross section instead of the high voltage electrode 111 of example 8. The high voltage electrode 112 having a square cross section was formed of stainless steel (SUS), and one side was 70 μm. Comparative example 7 uses a high voltage electrode 113 having a rectangular cross section instead of the high voltage electrode 111 of example 8. The high voltage electrode 113 having a rectangular cross section was formed of stainless steel (SUS), and the length in the longitudinal direction was 150 μm and the length in the short direction was 50 μm. The high voltage electrode 113 is arranged such that the longitudinal direction is disposed parallel to the surface of the counter electrode 120A. In comparative examples 6 and 7, the counter electrode 120A having no opening 130 was arranged in a homogeneous arrangement.

Fig. 17A and 17B are graphs showing the discharge current dependency of the dust collecting efficiency and the relationship between the dust collecting efficiency and the ozone concentration in example 8(AA), example 9(AB), and comparative example 1 (AA). Fig. 17A shows the discharge current dependence of the dust collection efficiency, and fig. 17B shows the relationship between the dust collection efficiency and the ozone concentration. In fig. 17A, the horizontal axis represents the discharge current (μ a) and the vertical axis represents the dust collection efficiency (%). In fig. 17B, the horizontal axis represents the ozone concentration (ppb) and the vertical axis represents the dust collection efficiency (%).

In fig. 17A, in comparative example 1(AA), the dust collecting efficiency increased with the discharge current. However, if the discharge current is not 450 μ A, the dust collecting efficiency is less than 99%.

On the other hand, in example 8(AA) using the high voltage electrode 111 having the racetrack shape, the dust collection efficiency was improved even in the low range (150 μ a and 250 μ a) of the discharge current, as compared with comparative example 1 (AA). That is, it can be seen that the amount of generated ions is increased by the high voltage electrode 111 having a racetrack shape.

In example 9(AB) using both the high voltage electrode 111 having the racetrack shape and the counter electrodes 120A and 120B arranged in an alternating arrangement, the dust collection efficiency is further improved in the low range of the discharge current.

Based on the relationship between the collection efficiency and the ozone concentration as shown in fig. 17B, it can be seen that according to example 8(AA) and example 9(AB) configured to obtain high collection efficiency at a low discharge current, the ozone concentration can be suppressed to be low while maintaining the high collection efficiency.

Fig. 18A and 18B are graphs showing the discharge current dependency of the dust collecting efficiency and the relationship between the dust collecting efficiency and the ozone concentration in example 8(AA), comparative example 1(AA), comparative example 6(AA), and comparative example 7 (AA). Fig. 18A shows the discharge current dependence of the dust collection efficiency, and fig. 18B shows the relationship between the dust collection efficiency and the ozone concentration. In fig. 18A and 18B, the horizontal axis and the vertical axis are the same as those in fig. 17A and 17B.

In fig. 18A, compared to comparative example 1(AA), in comparative example 6(AA) using the high voltage electrode 112 having a square cross section and comparative example 7(AA) using the high voltage electrode 111 having a rectangular cross section, the dust collecting efficiency was low even in the low range (150 μ a and 250 μ a) of the discharge current. Further, based on the relationship between the dust collecting efficiency and the ozone concentration as shown in fig. 18B, it can be seen that according to comparative example 6(AA) and comparative example 7(AA), when trying to obtain a high collecting efficiency, the amount of generated ions increases.

As described above, it is suitable that the elliptical corners of the high voltage electrode 111 have an arc shape and the angle thereof is not 90 °. That is, for the elliptical corners of the high voltage electrode 111 having the arc shape, it is appropriate that the arc shape has a radius of curvature (rw) equal to or more than 5% of the length (TW) of the short side and equal to or less than 50% (1/2) of the length (TW) of the short side. For example, the length (TW) of the short side is 50 μm to 100 μm, and the length (WW) of the long side is 0.6mm to 1.0 mm. The length (WW) of the long side is suitably greater than 1 and less than 4 relative to the length (TW) of the short side. If the length of the short side (TW) can be made smaller (shorter), it becomes the same as using the thin high voltage electrode 110 having a circular cross section. Further, if the length (WW) of the long side exceeds 4 with respect to the length (TW) of the short side, it is difficult to perform processing by using a linear member.

The high voltage electrode 111 may be formed of the same material as the high voltage electrode 110 described in the first embodiment.

Based on the relationship between the collection efficiency and the ozone concentration as shown in fig. 17B, it can be seen that according to example 8(AA) and example 9(AB) configured to obtain high collection efficiency at a low discharge current, the ozone concentration can be suppressed to be low while maintaining the high collection efficiency.

[ third embodiment ]

The dust collector 1 to which the first embodiment is applied and the dust collector 2 to which the second embodiment is applied are provided with the dust collector 20 using static electricity by using the high voltage electrode 210 and the counter electrode 220.

The dust collector 3 to which the third embodiment is applied uses a dust collecting filter.

Fig. 19 shows an example of the dust separator 3 according to the third embodiment.

The dust collector 3 to which the third embodiment is applied has a charger 10, a dust collection filter 50, a deodorizing filter 60, a fan 30, and a case 40 that accommodates the charger 10, the dust collection filter 50, the deodorizing filter 60, and the fan 30. The dust collector 20 to which the dust collector 1 of the first embodiment shown in fig. 1 is applied is replaced with a dust collecting filter 50. The deodorizing filter 60 may be appropriately provided on the front surface (upstream side) or the rear surface (downstream side) of the charger 10 and the rear surface (downstream side) of the dust collecting filter 50.

The charger 10 may be the same as the charger 10 shown in the embodiments in the dust catcher 1 to which the first embodiment is applied and the dust catcher 2 to which the second embodiment is applied.

Since the dust collection filter 50 is a fiber filter and is electret treated, suspended particles charged by the charger 10 are likely to be adsorbed. Further, it is suitable that the dust collection filter 50 has a large surface area by bending (pleating).

The numerical values shown in examples 1 to 9 are merely examples, and thus are not limited to these numerical values.

While the present disclosure has been described with various embodiments, various changes and modifications may be suggested to one skilled in the art. The present disclosure is intended to embrace these changes and modifications as fall within the scope of the appended claims.

Claims (15)

1. A charging device, comprising:

a plurality of counter electrodes formed in a plate shape and arranged in a direction intersecting with a ventilation direction to allow respective surfaces of the plurality of electrodes to follow the ventilation direction; and

a plurality of high voltage electrodes formed in a line shape and installed between the plurality of counter electrodes,

wherein the plurality of counter electrodes includes a first counter electrode having a first electrode area and a second counter electrode having a second electrode area smaller than the first electrode area,

wherein the first pair of electrodes and the second pair of electrodes are alternately arranged.

2. The charging device of claim 1,

the second pair of electrodes includes a via.

3. The charging device of claim 2,

the second pair of electrodes is configured such that the opening degree is higher on the leeward side than on the windward side.

4. The charging device of claim 2,

the second pair of electrodes is configured such that the center of gravity of the through-hole is located closer to the leeward side than the high-voltage electrode.

5. The charging device of claim 1,

the second pair of electrodes is formed in a plate shape such that a width of the second pair of electrodes in the ventilation direction is narrower than a width of the first pair of electrodes in the ventilation direction.

6. The charging device of claim 5,

the second pair of electrodes is arranged such that the distance between the windward end and the windward end of the first pair of electrodes is smaller than the distance between the leeward end and the leeward side of the first pair of electrodes.

7. The charging device of claim 1,

the ratio of the second pair electrode area to the first pair electrode area is greater than 50% and less than 90%.

8. The charging device of claim 1,

when the planar shape of the through-hole is a circle, the diameter is equal to or more than 2.5% and equal to or less than 60% of the width of the second pair of electrodes in the ventilation direction.

9. The charging device of claim 1,

the high voltage electrodes of the plurality of high voltage electrodes are disposed at the center or windward side of the ventilation direction of the first pair of electrodes.

10. The charging device of claim 1,

the high voltage electrodes of the plurality of high voltage electrodes have a circular cross section with a diameter equal to or greater than 20 μm and equal to or less than 300 μm.

11. The charging device of claim 1,

the high voltage electrodes of the plurality of high voltage electrodes comprise rectangular corners having an arc-shaped cross section.

12. The charging device of claim 11,

the high voltage electrode has an arc-shaped corner with a radius of curvature of 5% or more and 50% or less of the length of the short side of the cross-section.

13. The charging device of claim 11,

the high voltage electrode is configured such that the short side of the cross section is 50 μm or more and 100 μm or less.

14. The charging device of claim 11,

the high voltage electrode is configured such that the ratio of the length of the long side thereof to the length of the short side thereof exceeds 1 and is equal to or less than 4.

15. The charging device of claim 1,

the high voltage electrode of the plurality of high voltage electrodes includes one of a metal having any one of tungsten, copper, nickel, stainless steel, zinc, and iron, an oxide or an alloy containing the metal as a main component, and a material formed by plating a noble metal including silver, gold, or platinum on a surface of the metal or the oxide containing the metal as a main component.

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