JP2017060918A - Dust collector and air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dust collector and an air conditioner intended to realize both compactification and improved performance.SOLUTION: A dust collector according to an embodiment comprising: a counter electrode having a plurality of plate bodies in a first plate thickness direction; a discharge electrode having a tip end facing the counter electrode and having a plurality of plate protruding parts in a second plate thickness direction generally orthogonal to the first plate thickness direction; and a power supply applying a voltage between the discharge electrode and the counter electrode. The plurality of plate protruding parts are discharged by applying the voltage, and the plurality of plate bodies collect dust charged by the electric discharge.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to a dust collector and an air conditioner that capture dust by electrostatic force.

  An air cleaner is used to capture and clean the dust in the air. In recent years, an air conditioner (air conditioner) may have an air cleaning function. There are two types of air cleaners: a filter type and an electric dust collection type, which are appropriately selected or used in accordance with the properties of target particles and the size of the device. The electric dust collection type has a smaller fluid resistance than the filter type and can collect particles having a small particle size with relatively high efficiency.

  The electric dust collector includes a charging unit and a dust collecting unit that are arranged on the upstream side and the downstream side of the air flow (airflow). The charging unit has an ionization line (or needle electrode) and a counter electrode, and generates plasma. The charged particles in the plasma give a charge to the dust in the airflow. The dust collection unit has a dust collection electrode and a counter electrode, and captures charged dust with the dust collection electrode.

Japanese Patent Laying-Open No. 2015-66509 JP 2007-289832 A JP-A-11-212487 Japanese Patent No. 3358008 US Pat. No. 5,547,496 US Patent Application Publication No. 2004 / 0123739A1 JP 2014-147869 A

Here, the performance of the electrostatic precipitator includes various parameters (for example, the number and shape of the discharge electrodes, the shape and arrangement of the dust collection electrodes, the properties of the target particles (for example, the particle size), the speed of the air flow, and the discharge current. Density) is involved.
Generally, increasing the number of discharge electrodes is effective for improving the performance of an electrostatic precipitator. By increasing the number of discharge electrodes, more plasma spots (plasma regions) can be generated.
On the other hand, when the number of discharge electrodes is increased, the electrostatic precipitator is easily increased in size. In order to avoid this, it is conceivable to arrange the discharge electrodes close to each other. However, due to the close arrangement of the discharge electrodes, plasmas may interfere with each other, and the plasma intensity (density) per electrode may decrease. In this case, even if the discharge electrodes are arranged close to each other, the performance of the electric dust collector is not improved.
In addition, when the number of discharge electrodes is increased, resistance to airflow (ventilation resistance) also increases, and there is a possibility that the air conditioning performance (such as air conditioning) of the air conditioner may be adversely affected.
As described above, it is not easy to achieve both compactness and high performance of the electrostatic precipitator (particularly, the charging unit).

  An object of the present invention is to provide a dust collector and an air conditioner that achieve both compactness and high performance.

  The dust collector of the embodiment includes a counter electrode including a plurality of plate-like bodies in the first plate thickness direction, a tip that faces the counter electrode, and a second that is substantially orthogonal to the first plate thickness direction. And a power supply for applying a voltage between the discharge electrode and the counter electrode. The plurality of plate-like protrusions are discharged when the voltage is applied, and the plurality of plate-like bodies collect dust charged by the discharge.

It is a perspective view showing composition of electric dust collector 10 concerning an embodiment. It is a perspective view which shows the structure of the electric dust collector 10x which concerns on a comparative example. It is a schematic diagram showing distribution of the plasma Pl in the discharge electrode 11x which concerns on a comparative example. It is a schematic diagram showing distribution of the plasma Pl in the discharge electrode 11x which concerns on a comparative example. It is a schematic diagram showing distribution of the plasma Pl in the discharge electrode 11x which concerns on a comparative example. It is a schematic diagram showing distribution of the plasma Pl in the discharge electrode 11 which concerns on embodiment. It is a schematic diagram showing distribution of the plasma Pl in the discharge electrode 11 which concerns on embodiment. It is a schematic diagram showing distribution of the plasma Pl in the discharge electrode 11 which concerns on embodiment. It is a graph showing the relationship between the space | interval of the plate-shaped electrode 111, and a plasma intensity | strength (charged particle density). It is a figure which shows an example of arrangement | positioning of the plate-shaped electrode. It is a figure which shows an example of arrangement | positioning of the plate-shaped electrode. It is a figure which shows an example of arrangement | positioning of the plate-shaped electrode. It is a figure showing the electric potential distribution between the discharge electrode 11 and the counter electrode 12, and the locus | trajectory of the charged dust Pti. 3 is a plan view showing an example of a plate electrode 111. FIG. 3 is a plan view showing an example of a plate electrode 111. FIG. 3 is a plan view showing an example of a plate electrode 111. FIG. 3 is a plan view showing an example of a plate electrode 111. FIG. 2 is a perspective view showing an example of a plate electrode 111. FIG. 2 is a perspective view showing an example of a plate electrode 111. FIG. It is a side view which shows the plate-shaped electrode 111 of FIG. 12A. 2 is a perspective view showing an example of a plate electrode 111. FIG. 2 is a perspective view showing an example of a discharge electrode 11. FIG. 2 is a perspective view showing an example of a discharge electrode 11. FIG. 5 is a plan view illustrating an example of a method for manufacturing the discharge electrode 11. 3 is a perspective view illustrating an example of electrical connection of a plate electrode 111. FIG. 3 is a perspective view illustrating an example of electrical connection of a plate electrode 111. FIG. 3 is a perspective view illustrating an example of electrical connection of a plate electrode 111. FIG. 3 is a perspective view illustrating an example of electrical connection of a plate electrode 111. FIG. 3 is a perspective view illustrating an example of a counter electrode 12. FIG. 3 is a perspective view illustrating an example of a counter electrode 12. FIG. 3 is a perspective view illustrating an example of a counter electrode 12. FIG. 3 is a perspective view illustrating a positional relationship between a plate electrode 111 and a counter electrode 12. FIG. It is a mimetic diagram showing composition of air harmony machine 20 concerning an embodiment.

Hereinafter, embodiments will be described in detail with reference to the drawings.
FIG. 1 is a perspective view illustrating a configuration of an electric dust collector 10 according to the embodiment.

  The electrostatic precipitator 10 includes a discharge electrode 11, a counter electrode 12, and a DC power supply 13 and is disposed in the airflow AF. The direction in which the discharge electrode 11 and the counter electrode 12 are arranged is the X-axis direction, and the X, Y, and Z axes are orthogonal to each other. These points are the same in other drawings.

The airflow AF is a flow of gas (particularly air) and flows in the X-axis direction. The air flow AF may be any of a forced flow generated by a blowing means such as a fan, a natural wind, a non-forced flow generated by a temperature difference, or the like.
When the airflow AF is a forced flow, the electrostatic precipitator 10 is disposed in a ventilation path installed corresponding to the blowing means. Note that this ventilation path is sufficient if the air flow AF passes, and may be in an open state or a closed state.

The discharge electrode 11 and the counter electrode 12 are respectively installed on the upstream side and the downstream side of the airflow AF.
The discharge electrode 11 is an electrode for generating plasma, and has a plurality of plate-like electrodes (plate-like needle electrodes) 111 (111 (1) to 111 (i) to 111 (n)). For ease of understanding, the description of the plate electrodes 111 (3) to 111 (n-2) is omitted.

The plate-like electrode 111 is composed of a plate-shaped conductor, and has a plurality of plate-like protrusions (needle electrodes) 112 and connection portions 113.
Here, the plate-like projections 112 and the connection portions 113 on the same plate-like electrode 111 are arranged on substantially the same plane. As will be described later, the plate-like protrusion 112 and the connecting portion 113 do not have to be arranged on the same plane.

  The plate-like projecting portion 112 is a substantially isosceles triangular plate-like body, and has a line-symmetric shape with respect to an axis A2 parallel to the X axis. However, as will be described later, the shape of the plate-like protrusion 112 may not have line symmetry.

The tips of the plate-like projections 112 on the same plate-like electrode 111 are arranged on the axis A1 parallel to the Z-axis (in a direction substantially perpendicular to the plate thickness direction of the plate-like projection 112) with a distance dz. The
Further, the tips of the plate-like projections 112 on the different plate-like electrodes 111 are arranged at an interval dy in the Y-axis direction (the plate thickness direction of the plate-like projection 112).
That is, the tip of the plate-like protrusion 112 is disposed on a plane parallel to the YZ plane.

  However, it is also possible to arrange the tip of the plate-like protrusion 112 on a curved surface. In this case, it is preferable that the facing surface 122 of the facing electrode 12 has a shape corresponding to the surface on which the tip of the plate-like protrusion 112 is disposed. This is because the discharge from the tip of the plate-like protrusion 112 is made uniform.

  The tip of the plate-like protrusion 112 faces the counter electrode 12 and faces the direction of the counter electrode 12 (here, the X-axis positive direction). Unlike the comparative example described later, in this embodiment, the tips of the plate-like protrusions 112 are not opposed to each other. Since the tip of the plate-like projection 112 faces the counter electrode 12, the installation density of the plate-like projection 112 and thus the performance of the electrostatic precipitator 10 can be improved. Details of this will be described later.

  The connection portion 113 is a substantially rectangular plate-like body, and mechanically and electrically connects and fixes the plate-like protrusions 112 to each other.

The counter electrode 12 has a fin shape and functions as both a counter electrode and a collecting electrode. The counter electrode 12 is arranged in the Z direction with a plurality of plate-like bodies 121 facing each other with a distance Dz. The plate-like body 121 has a facing surface (end surface) 122 that faces the discharge electrode 11. The opposing surfaces 122 of the plurality of plate-like bodies 121 are arranged on a plane parallel to the YZ plane. This plane is arranged in parallel with the surface on which the tip of the plate-like projection 112 is arranged at a distance G (distance between the discharge electrode 11 and the counter electrode 12).
A gap between the plate-like bodies 121 is a flow path FP through which the airflow AF passes.

  The counter electrode 12 (plate-like body 121) is preferably covered with a hydrophilic material (for example, a hydrophilic resin). It becomes easy to clean the counter electrode 12 and collect the collected dust (improvement of maintenance of the electric dust collector 10).

  The DC power source 13 applies a high-voltage DC voltage (applied voltage Va) between the discharge electrode 11 and the counter electrode 12. The DC power source 13 applies a negative (or positive) voltage Va of several kV (for example, about 6 to 12 kV) to the discharge electrode 11 to set the counter electrode 12 to the ground potential.

  When the voltage Va is applied to the discharge electrode 11, the electric field concentrates on the tip of the plate-like protrusion 112. When the applied voltage Va becomes sufficiently large (when the electric field strength near the tip of the plate-like projection 112 reaches the dielectric breakdown electric field), dielectric breakdown occurs at the tip of the plate-like projection 112 and discharge starts. That is, neutral molecules of gas (for example, nitrogen or oxygen in the air) in the airflow AF are charged and become ions (charged particles) (ionization). As a result, plasma Pl is generated in a region between the discharge electrode 11 and the counter electrode 12 (more precisely, a region covering the tip of the plate-like protrusion 112 and facing the counter electrode 12).

  When the airflow AF passes through the plasma Pl and the vicinity thereof, the charge of charged particles (positive, negative ions and electrons, mainly negative ions) in the plasma Pl adheres to the dust Pt in the airflow AF (charging), It becomes charged dust Pti. The charged dust Pti receives electrostatic force from the electric field between the discharge electrode 11 and the counter electrode 12, and is attracted to and captured by the counter electrode 12 having the ground potential.

  Although not shown, the discharge electrode 11 and the counter electrode 12 (particularly, the discharge electrode 11) may be surrounded by a frame of an insulating material (for example, ABS resin). It is possible to prevent a human body from touching the discharge electrode 11 and receiving an electric shock. This frame is also useful for securing the strength of the electric dust collector 10.

  If the applied voltage Va is about several kV, the distance G between the discharge electrode 11 and the counter electrode 12 is about 5 to 30 mm, more preferably about 10 to 20 mm. A certain amount of distance G is required to suppress abnormal discharge. The distance G needs to be increased as the applied voltage Va increases.

The plate thickness of the plate electrode 111 is preferably 0.1 to 2 mm, more preferably 0.2 to 0.5 mm (for example, about 0.3 mm).
When the plate thickness is smaller than 0.1 mm, the strength of the needle-like electrode 111 is reduced, and there is a possibility that the needle-shaped electrode 111 is bent during use of the electrostatic precipitator 10. If the plate thickness is larger than 2 mm, processing (creation) of the plate electrode 111 and discharge from the plate electrode 111 may be difficult.

  The interval dy in the Y-axis direction (vertical direction) of the plate-like projection 112 is preferably 2 to 20 mm, more preferably 5 to 15 mm (for example, about 10 mm). Details of this will be described later.

  The interval dz in the Z-axis direction (left-right direction) of the plate-like protrusion 112 is preferably 5 to 20 mm, more preferably 10 to 15 mm (for example, about 13 mm).

  As indicated above, the spacing dy is typically smaller than the spacing dz. This can be explained by a collecting mechanism of charged dust Pti, which will be described later with reference to FIG. That is, since the electric field in the Z direction derived from the shape of the plate-like protrusion 112 contributes to collection, the potential change between the plate-like protrusions 112 (of the same plate electrode 111) in the Z-axis direction is increased. Is desirable. Therefore, the interval dz is preferably about 10 mm as described above.

  On the other hand, the potential change in the Y-axis direction related to the interval dy, that is, the electric field in the Y-axis direction does not substantially contribute to collection. Therefore, the electric dust collector 10 can be made compact by reducing the interval dy.

  The length L of the plate-like protrusion 112 is preferably 3 to 15 mm, more preferably 5 to 15 mm (for example, about 10 mm).

  The interval Dz between the plate-like bodies 121 is preferably 0.1 to 5 mm, more preferably 0.5 to 2 mm (for example, about 1 mm).

  The ratio R (= dz / Dz) of the distance Dz of the plate-like body 121 to the distance dz of the plate-like projection 112 is preferably 5 to 20, more preferably 10 to 15 (for example, about 10).

  That is, it is preferable that the distance Dz between the plate-like bodies 121 is sufficiently smaller than the distance dz between the plate-like protrusions 112. By reducing the distance Dz of the plate-like body 121 as compared with the distance dz, the discharge state becomes closer to the case where the entire counter electrode 12 is flat. That is, the variation in plasma intensity for each plate-like projection 112 is suppressed, and the need to align each plate-like projection 112 with the plate-like body 121 is reduced.

  Here, there is a possibility that a part of the plate-like protrusion 112 does not discharge. A discharge current flows between the discharge part (plasma generation spot) on the plate-like protrusion 112 and the counter electrode 12 to form an electric circuit. In this electric circuit, current flows preferentially in a portion where the load (resistance) is small. Therefore, if the electrical conditions of the plate-like projections 112 are different, there is a possibility that some of the plate-like projections 112 do not discharge.

In order to prevent this and to generate plasma with uniform intensity from all the plate-like projections 112, the following ideas can be considered.
The distance G between the plate-like protrusion 112 and the counter electrode 12 is made uniform. For example, the difference in the distance G for each plate-like protrusion 112 is set to 1 mm or less.
The tip shape of the plate-like protrusion 112 is made as sharp as possible.
All the plate-like projections 112 are set to the same potential (details will be described later).

(Comparative example)
FIG. 2 is a perspective view showing the configuration of the electrostatic precipitator 10x according to the comparative example.
The electrostatic precipitator 10x includes a discharge electrode 11x, a counter electrode 12, and a DC power source 13, and is disposed in the airflow AF.

The discharge electrode 11x is an electrode for generating plasma, and has a plurality of plate electrodes 111x.
The plate-like electrode 111x is a plate-like electrode disposed substantially parallel to the counter electrode 12 (on a plane parallel to the YZ plane), and has a plurality of plate-like projections 112x and connection portions 113x. Two plate-like projections 112x are arranged above and below the connection portion 113x (Y direction).
As a result, unlike the embodiment, the tips of the plate-like protrusions 112x of the different plate-like electrodes 111x face each other.

(Improved dust collection performance and downsizing)
Hereinafter, the compatibility between the compactness and high performance of the electrostatic precipitator 10 will be described with reference to a comparative example.

  The dust collection performance of the electric dust collector 10 is determined by charging efficiency (how much dust Pt can be charged) and collection efficiency (how much charged dust Pti can be collected).

A. Densification of the plate electrode 111 and the intensity of the plasma Pl The intensity of the plasma Pl from the discharge electrode 11 greatly contributes to improvement of both charging efficiency and collection efficiency.

  The plasma Pl is generated from the tip of the plate-like protrusion 112. For this reason, it is conceivable to increase the strength of the plasma Pl and thus the dust collection performance of the electric dust collector 10 by increasing the number of the plate-like projections 112. In order to achieve both compactness and high performance of the electric dust collector 10, it is only necessary to increase the density of the plate-like protrusions 112.

  However, when the plate-like protrusions 112 are arranged close to each other, the plasmas interfere with each other (plasma interference), and the strength decreases. In order to achieve both compactness and high performance of the electric dust collector 10, it is necessary to suppress this plasma interference.

The suppression state of plasma interference is greatly different between the embodiment and the comparative example.
FIGS. 3A to 3C and FIGS. 4A to 4C are schematic diagrams showing the distribution of the plasma Pl when the distance dy between the plate electrodes 111x and 111 is changed in the electric dust collectors 10x and 10 according to the comparative example and the embodiment. FIG.

  3A and 4A, the interval dy between the plate electrodes 111x and 111 is sufficiently large. At this time, since the plasma Pl is sufficiently separated, they do not interfere with each other.

  In FIG. 3B and FIG. 4B, the space | interval dy between plate-shaped electrodes 111x and 111 is small, and plasma Pl has overlapped. In these figures, the distribution of the plasma Pl does not change even if the plasma Pl overlaps.

  If the state as shown in FIGS. 3B and 4B is realized, the plasma spot increases by increasing the density of the plate electrodes 111x and 111, and the dust collection performance of the electrostatic precipitators 10x and 10 is increased accordingly. Will improve.

However, as shown in FIGS. 3C and 4C, when the distance dy between the plate electrodes 111x and 111 becomes small, the plasma Pl interferes and the intensity of the plasma Pl decreases. That is, the plasma density (charged particle density) is reduced, the dust charging efficiency is reduced, and the dust collection performance is lowered.
For this reason, even if the density of the plate electrodes 111x and 111 is increased, the dust collection performance of the electric dust collectors 10x and 10 is not improved.

  This decrease in the intensity of the plasma Pl can be supported by the emission intensity of the plasma Pl. That is, when the distance dy between the plate electrodes 111x and 111 is reduced to some extent, the emission intensity of the plasma Pl is reduced.

Here, as shown in FIGS. 3C and 4C, the degree of intensity reduction of the plasma Pl is greatly different between the plate-like electrodes 111x and 111x. When the interval dy is reduced, the intensity of the plasma Pl is greatly reduced in the plate-like electrode 111x, but the intensity of the plasma Pl is not so lowered in the plate-like electrode 111.
As described above, in the present embodiment, the plasma interference can be suppressed due to the directionality of the plasma distribution.

In both the comparative example and the embodiment, the plasma Pl is generated from the tips of the plate electrodes 111 x and 111, and has a distribution that extends around the tips and toward the counter electrode 12.
Further, the plasma Pl is directed away from the plate electrodes 111x and 111. This is because the plate-like electrodes 111x and 111 themselves have the same potential, so that the electric field is not concentrated on the surfaces of the plate-like electrodes 111x and 111, and it is difficult for discharge to occur.

  In the present embodiment, the tip of the plate-like protrusion 112 faces (opposites) the counter electrode 12. For this reason, the plasma Pl generated from the plate-like protrusion 112 extends in the direction of the counter electrode 12 (X-axis direction). As a result, when the plate-like projections 112 are brought close to each other, the overlap of the plasma Pl is relatively small and the strength reduction is small (suppression of plasma interference).

  In the comparative example, the tip of the plate-like protrusion 112x does not face the counter electrode 12. For this reason, the plasma Pl generated from the plate-like protrusion 112x extends (inclined in the Y-axis direction) in a direction inclined from the direction of the counter electrode 12 (X-axis direction). As a result, when the plate-like projections 112x are brought close to each other, the overlap of the plasma Pl is large and the strength is greatly reduced.

  In the comparative example, in order to prevent a decrease in plasma intensity, when the applied voltage Va is 6 kV, and the distance G between the plate-like protrusion 112x and the counter electrode 12 is about 10 mm, the distance dy between the tips of the plate-like protrusion 112x. Of about 50 mm or more. That is, in the comparative example, each time one plate-like electrode 111x (a pair of upper and lower plate-like protrusions 112x) is added, the height (Y-direction size) of the electrostatic precipitator 10x is at least 50 mm (more precisely, 50 mm + the length L × 2 of the plate electrode 111).

  In the embodiment, the plasma intensity can be generally maintained even if the interval dy between the plate-like protrusions 112 is reduced to, for example, about 2 mm. Thus, for example, a compact electrostatic precipitator 10 having a height of about 18 mm (= dy * (n−1) = 2 * 9) can be created using ten (n = 10) plate-like electrodes 111. That is, as compared with the comparative example (the interval dy is about 50 mm and the addition of the two plate-like protrusions 112x), the number of the plate-like protrusions 112 can be arranged five times or more in a space less than half.

  By increasing the density of the plate-like projections 112, the draft resistance may increase, and the dust collection performance per plate-like projection 112 may decrease. However, in many cases, the plate thickness of the plate electrode 111 is assumed to be relatively thin (for example, within 1 mm). For this reason, it is considered that the ventilation resistance does not increase so much even if the density of the plate-like protrusions 112 is increased. Therefore, compared with the comparative example, the embodiment can sufficiently improve the dust collection performance.

FIG. 5 is a graph showing the relationship between the distances dy and dx between the plate-like electrodes 111 and the plasma intensity PP (charged particle density).
The horizontal axis of the graph represents the distances dy and dx between the plate electrodes 111, and the vertical axis represents the plasma intensity PP (charged particle density). The plasma intensity PP is a normalized plasma intensity and is derived from the discharge current. This is because the discharge current is a flow of charged particles, and if the same measurement circuit is used, the increase in current and the amount of plasma generated correspond approximately.

The graph G1 corresponds to the case where the plate-like electrodes 111 parallel to the YZ plane are arranged to face each other with an interval dy in the Y direction (see FIG. 6).
Graph G2 corresponds to the case where plate-like electrodes 111 parallel to the YZ plane are arranged in parallel in the X direction at intervals dx (see FIG. 7).
The graph G3 corresponds to the case where the plate electrodes 111 parallel to the XZ plane are arranged in parallel in the Y direction at an interval dy (see FIG. 8).

In the graph G1, when the interval dy is reduced, the plasma intensity PP is greatly reduced. On the other hand, in the graph G3, when the interval dy is reduced, the plasma intensity PP does not decrease so much and is suitable for downsizing.
In the graph G2, it is considered that the plasma intensity PP is small regardless of the distance dx, and the plate electrode 111 far from the counter electrode 12 does not substantially contribute to the discharge.

B. Improving the collection efficiency of the charged dust Pti As described above, the charged dust Pti is attracted to and collected by the counter electrode 12 by the electric field formed between the discharge electrode 11 and the counter electrode 12. Since this electric field contributes to the collection of dust Pt, it is called a collection electric field. In order to improve the collection efficiency, it is important to control the collection electric field.

  FIG. 9 is a diagram illustrating the potential distribution between the discharge electrode 11 and the counter electrode 12 and the locus of the charged dust Pti. Here, the result of computer simulation (numerical calculation) when a voltage of −6 kV (−6000 V) is applied between the discharge electrode 11 and the counter electrode 12 is shown.

  The shading in FIG. 9 corresponds to the potential [V]. The potential changes from −6000 V to 0 V as the discharge electrode 11 approaches the counter electrode 12. The shading boundary is a potential contour line, and an electric field E is formed in a direction perpendicular to the contour line.

The direction of the electric field E is basically the X-axis direction, but since the electric field E is concentrated on the tip of the plate-like protrusion 112, it has a component in the Z-axis direction in the vicinity of the plate-like protrusion 112.
For this reason, the charged dust Pti moves in the positive and negative directions of the Z-axis due to the Z-axis direction component of the electric field while moving in the X-axis direction (direction toward the counter electrode 12). The charged dust Pti collides with the counter electrode 12 (the side surface of the plate-like body 121 and the counter surface 122) and is collected. The charged dust Pti that has not been collected passes between the plate-like bodies 121 (flow path FP) and is discharged from the electric dust collector 10.

  Assuming that the direction of the electric field E is only in the X-axis direction, a force only in the X-axis direction is applied to the charged dust Pti, so that it easily passes between the plate-like bodies 121 (flow path FP). That is, it is important that the electric field E has a Z-axis direction component (referred to as a transverse electric field) to improve the collection efficiency of the charged dust Pti.

(1) Relationship between the plate-like electrode 111 (plate-like projection 112) and the plate-like body 121 in the plate thickness direction The plate-like projection 112 (plate-like electrode 111) can effectively utilize the lateral electric field for collecting. A geometric arrangement is preferred.
In the present embodiment, each of the plate-like protrusion 112 and the plate-like body 121 has directionality (plate thickness direction). In this case, as in the embodiment, it is preferable that the plate thickness directions of the plate-like protrusion 112 and the plate-like body 121 are substantially perpendicular to each other. In this case, as shown in FIG. 9, the collection efficiency of the charged dust Pti can be improved by using a lateral electric field in the Z-axis direction (the width direction of the plate-like protrusion 112).
In addition, a certain amount of width (for example, 90 ° ± 10 °) is recognized as the angle in the plate thickness direction between the counter electrode 12 and the plate-like body 121.

(2) Arrangement in the Y-axis direction at the tip of the plate-like projection 112 As described above, in the present embodiment, the tip of the plate-like projection 112 on the different plate-like electrode 111 is arranged in the Y-axis direction (the plate-like projection 112). (In the plate thickness direction) (phases are aligned). With this arrangement, the lateral electric field formed by the plurality of plate-like protrusions 112 can be effectively utilized. If the tip of the plate-like projection 112 is not arranged in the Y-axis direction (its plate thickness direction), the lateral electric fields from the respective plate-like projections 112 cancel each other and may not be used effectively.

(Modification)
Hereinafter, modifications of the electric dust collector 10 will be described.
(1) Shape of Plate-like Projection 112 FIG. 10A to FIG. 10D are plan views illustrating an example of the shape of the plate-like electrode 111 (discharge electrode 11).

  In the embodiment, the plate-like protrusion 112 has a symmetrical shape in the left-right direction (Z-axis direction) such as an isosceles triangle (including a regular triangle) (see FIG. 10A).

  The plate-like protrusion 112 may be an asymmetric triangle (see FIG. 10B). At this time, the plate-like protrusion 112 faces in an oblique direction. Thus, the direction of the plate-like protrusion 112 may be inclined to some extent from the X-axis direction.

The plate-like protrusion 112 may have a plurality of protrusions (the tip branches into a plurality of branches) (see FIG. 10C). At this time, the plate-like protrusion 112 may be asymmetrical in the left-right direction (Z-axis direction).
The plate-like protrusion 112 may be a wire-like wire or a thin bar shape (see FIG. 10D).

  11 and 13 are perspective views showing an example of the plate electrode 111. FIG. 12A and 12B are a perspective view and a side view showing an example of the plate electrode 111.

The plate-like protrusion 112 may be bent (see FIG. 11).
Plate-shaped protrusions 112a and 112b having different shapes may be connected to the connection portion 113 (see FIGS. 12A and 12B).
Here, the direction of the plate-like projections 112a and 112b is changed between the positive direction and the negative direction of the Y axis. At this time, the plate-like protrusions 112a and 112b are not arranged on the same plane as the connection portion 113, and the plate-like electrode 111 as a whole has a three-dimensional shape.

The connecting portion 113 may be disposed on the YZ plane, and the plate-like protrusion 112 may be bent (see FIG. 13).
Here, the plate-like protrusion 112 is bent to face the X-axis direction (counter electrode 12). This is the same shape as the plate-like protrusion 112x of the plate-like electrode 111x of the comparative example is bent.

  In this way, even if the plate-like protrusion 112 (or only the tip thereof) is directed toward the counter electrode 12, the direction of the plasma Pl is set as the direction of the counter electrode 12 (X-axis direction), and the height of the plate electrode 111 is increased. Plasma interference during density can be suppressed.

14 and 15 are perspective views showing an example of the discharge electrode 11.
A plurality of plate-like electrodes 111 can be mechanically and electrically connected in the Y-axis direction with a conductive (for example, metal) connection member 114 to form an integrated discharge electrode 11.

A plurality of plate-like projections 112 connected by the connecting portion 115 may be formed by cutting and bending the conductive plate material (see FIG. 15). At this time, the airflow AF can pass through the opening 116.
In addition, in order to reduce the ventilation resistance of the discharge electrode 11, it is preferable to reduce the area of the connection part 115 (for example, opening is provided).

Hereinafter, the manufacturing method of the discharge electrode 11 is demonstrated.
The plate-like electrode 111 shown in FIGS. 10A to 10D can be formed by punching from a single conductor plate (metal plate) or laser processing. Of these, punching is cheap and suitable for mass production.

In the plate-like electrode 111 (discharge electrode 11) shown in FIGS. 11, 12A, 12B, 13, and 14, the plate-like protrusion 112 or a part thereof may be bent after punching.
As described above, the discharge electrode 11 shown in FIG. 15 can be created by bending a cut plate CL in a conductive plate M (see FIG. 16).

As described above, in order to generate plasma of equal strength from all the plate-like projections 112, it is preferable that the plurality of plate-like projections 112 have the same potential. For this purpose, the following means can be employed.
A plurality of plate electrodes 111 are connected by conducting wires, and a voltage is applied from one DC power supply 13 (see FIG. 17A).
The same voltage is applied to the plurality of plate electrodes 111 from the plurality of power supplies 13a to 13c (see FIG. 17B).
The side surfaces or back surfaces of the plurality of plate-like electrodes 111 are connected by a conductive connecting member (for example, a metal frame) 114 (see FIGS. 18A and 18B).
-The discharge electrode 11 whole is created in a lump from a conductive plate material (see Figs. 14 to 16).
In order to improve the strength of the discharge electrode 11, an insulating frame may be added as necessary.

(2) Shape of Counter Electrode 12 FIGS. 19A to 19C are perspective views illustrating an example of the counter electrode 12.
As in the embodiment, the counter electrode 12 may have a fin shape (see FIG. 19A). That is, the plate-like bodies 121 can be arranged to form the counter electrode 12.

  The counter electrode 12 may have a mesh shape (see FIG. 19B) or a honeycomb shape (see FIG. 19C). In other words, a block having a rectangular column or hexagonal column through-hole (flow path FP) is used as the counter electrode 12. The size and density of the through hole can be determined in relation to the ventilation resistance.

  When the counter electrode 12 is formed in a mesh shape or a honeycomb shape, there is less room for the relationship between the discharge electrode 11 and the plate electrode 111 in the plate thickness direction (stacking direction) (see FIG. 20). That is, since the flow path FP is oriented in a uniaxial direction (X-axis direction), the angular relationship with the flow path FP does not change even if the laminating direction (plate thickness direction) of the plate electrodes 111 changes.

  On the other hand, in the fin-shaped counter electrode 12 as shown in FIG. 19A, the flow path FP extends in the Y-axis direction, so that the flow path changes when the stacking direction (plate thickness direction) of the plate electrodes 111 changes. The angular relationship with the FP changes. As described above, the stacking direction (plate thickness direction) of the plate-like electrode 111 and the stacking direction (plate thickness direction) of the plate-like body 121 are preferably orthogonal from the viewpoint of improving the collection efficiency.

(Air conditioner 20)
The electric dust collector 10 can be incorporated in an air conditioner (air conditioner).
FIG. 21 is a schematic diagram illustrating a configuration of the air conditioner 20 according to the embodiment.
The air conditioner 20 includes an indoor unit 21 and an outdoor unit 22.
The indoor unit 21 and the outdoor unit 22 are connected by a connecting portion 23, and the refrigerant circulates between them. That is, heat moves from the indoor unit 21 to the outdoor unit 22 (cooling) or in the opposite direction (heating) using the refrigerant.

  The indoor unit 21 includes a filter 24, a discharge electrode 11, a heat exchanger 25, a partition wall 26, and a fan 27, and the airflow AF flows in and out. Among these, the combination of the discharge electrode 11 and the heat exchanger 25 functions as an electric dust collector by applying a DC voltage from a DC power source (not shown).

The filter 24 filters and removes relatively large dust (dust) in the airflow AF.
The discharge electrode 11 charges relatively small dust in the airflow AF, and the discharge electrode 11 of the embodiment and the modification can be used.

  The heat exchanger 25 captures charged dust as well as heat exchange between the airflow AF and the refrigerant. That is, the heat exchanger 25 also functions as the counter electrode 12 of the electric dust collector 10.

  The heat exchanger 25 has a plurality of plate-like bodies 121 and pipes 28. As described above, the plurality of plate-like bodies 121 are arranged to face each other in the Z direction. These plate-like bodies 121 are formed of a material (for example, metal) having good electrical conductivity and thermal conductivity, and are connected to the pipe 28. For this reason, the plate-like body 121 exchanges heat with the refrigerant in the pipe 28.

  A high DC voltage is applied between the discharge electrode 11 and the heat exchanger 25. As a result, plasma is generated from the discharge electrode 11 and the dust is charged and captured by the plate-like body 121 in the heat exchanger 25.

The partition wall 26 is for changing the direction of the airflow AF flowing out from the heat exchanger 25. A fan 27 is installed in the space partitioned by the partition wall 26, and an air flow AF from the filter 24 toward the heat exchanger 25 is formed.
As described above, the air conditioner 20 has a dust collection function as well as an air conditioning function.

  Note that the air conditioner 20 may have a horizontally long shape that is longer in the Z-axis direction than in the Y-axis direction due to the installation in the room. In this case, the discharge electrode 11 and the heat exchanger 25 are also horizontally long, and the length in the Y-axis direction is relatively short (height is low).

  At this time, if the stacking direction (plate thickness direction) of the plate electrodes 111 in the discharge electrode 11 is the Y-axis direction, the number of the plate electrodes 111 (stacking number) may be relatively small. That is, the density of the plate-like protrusions 112 can be secured with a relatively small number of laminated layers, and the discharge electrode 11 can be easily manufactured.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 10 ... Electric dust collector, 11 ... Discharge electrode, 111 ... Plate electrode, 112 ... Plate-shaped projection part, 113 ... Connection part, 114 ... Connection member, 115 ... Connection part, 116 ... Opening, 12 ... Counter electrode, 121 ... Plate 122: opposing surface, 13: DC power supply, AF: airflow, FP ... flow path, Pl ... plasma, Pt ... dust, Pti ... charged dust, 20 ... air conditioner, 21 ... indoor unit, 22 ... outdoor unit , 23 ... connection part, 24 ... filter, 25 ... heat exchanger, 26 ... partition wall, 27 ... fan, 28 ... piping

Claims (7)

A counter electrode comprising a plurality of plate-like bodies in the first thickness direction;
A discharge electrode having a plurality of plate-like protrusions in a second plate thickness direction having a tip facing the counter electrode and substantially perpendicular to the first plate thickness direction;
A power source for applying a voltage between the discharge electrode and the counter electrode,
The plurality of plate-like protrusions are discharged by applying the voltage,
The plurality of plate-like bodies collect dust charged by the discharge,
Dust collector. The dust collector according to claim 1, wherein the plurality of plate-like protrusions are arranged in a direction substantially perpendicular to the first plate thickness direction. The discharge electrode is
The dust collector according to claim 1, further comprising a plurality of second plate-like protrusions having a second tip facing the counter electrode and in the second plate thickness direction. The plurality of plate-like projections and the plurality of second plate-like projections are arranged in the first plate thickness direction.
The dust collector according to claim 3. The interval between the plurality of plate-like protrusions is larger than the interval between the plurality of plate-like bodies.
The dust collector according to claim 3 or 4. The dust collection according to any one of claims 3 to 5, wherein an interval between the plurality of plate-like projections and the plurality of second plate-like projections is smaller than an interval between the plurality of plate-like projections. apparatus.   The air conditioner which comprises the dust collector of any one of Claims 1 thru | or 6.