JP6812846B2 - Electrostatic precipitator - Google Patents

Description

The present invention relates to an electrostatic precipitator, particularly an electrostatic precipitator used in an air conditioner or an air purifier.

Conventionally, in an air conditioner or an air purifier, an electrostatic precipitator provided with a charged unit for charging dust and dirt and a dust collecting unit for collecting the charged dust and dirt is provided. Normally, a plurality of rectangular sheet-shaped electrodes are arranged facing each other in the dust collecting portion, and by this arrangement, an electrostatic field is formed between the electrodes to collect dust and dirt. .. The housing of the dust collector is provided with ribs that sandwich and fix the electrodes, and these ribs fix one of the electrodes on the high voltage side and the electrodes on the ground side. The electrodes are provided with notches so as not to come into contact with the ribs in order to ensure insulation between electrodes having different polarities.

However, since the corners of the notch are sharp, there is a problem that the electric field is concentrated on the corners and the potential of the electrode is lowered due to the extra discharge to the ribs, and the dust collection performance is lowered.

In order to solve this problem, for example, a technique is disclosed in which the corners of the electrode are formed in a curved shape to suppress the concentration of the electric field on the corners so that the discharge is difficult (for example, Patent Document 1). reference).

However, when both ends of the notched electrode are curved, air flows along the surface of the electrode, so that there is a problem that the proportion of air flowing on the electrode is reduced.

Japanese Unexamined Patent Publication No. 5-329398

The present invention has been made in view of the above problems, and an object of the present invention is to provide an electrostatic precipitator in which insulation is ensured and the surface area of an electrode through which air passes is increased. To do.

The present invention is grasped by the following configuration in order to achieve the above object.
(1) The first aspect of the present invention is an electrostatic precipitator, which comprises a charged portion that charges dust contained in the air, a dust collecting portion that collects dust charged by the charged portion, and the like. The dust collecting portion includes a plate-shaped high-pressure electrode plate, a plate-shaped collecting electrode plate, a rib for a high-pressure electrode plate, and a rib for a collecting electrode plate, and the surface of the high-pressure electrode plate. The high-pressure electrode plates are alternately arranged in parallel with the surfaces of the collection electrode plates facing each other, and the high-pressure electrode plates are fixed to the ribs for the high-pressure electrode plates and to avoid contact with the ribs for the collection electrode plates. The second notch is provided so that the collection electrode plate is fixed to the rib for the collection electrode plate and the second notch is for avoiding contact with the rib for the high pressure electrode plate. The first cutout portion and the corner portion on the opening side of at least one of the second cutout portions are formed in a rounded shape, and the corresponding ribs for the collecting electrode plate and the ribs for the high pressure electrode plate are formed. At least one of the corner portions is formed so as to follow the rounded shape of the corner portion.

According to the present invention, air flows along the ribs without causing an electric discharge in the electrode of the dust collecting part, so that the time flowing on the surface of the electrode is lengthened and the dust can be collected as much as possible. A dust collector can be provided.

It is a perspective view which shows disassembled the electrostatic precipitator which concerns on embodiment of this invention. It is a perspective view which shows the appearance of the dust collecting part which concerns on embodiment of this invention. It is a perspective view which shows the internal structure of the dust collecting part which concerns on embodiment of this invention. It is sectional drawing which shows the relationship between the collector sheet and the rib of the dust collecting part which concerns on embodiment of this invention, (a) is the relationship between a collector sheet (high-voltage electrode plate) and a rib for a high-voltage electrode plate, (b). ) Indicates the relationship between the collector sheet (collection electrode plate) and the rib for the collection electrode plate. It is a top view which shows the collector sheet (high voltage electrode plate) of the dust collecting part which concerns on the conventional electrostatic precipitator. It is a top view which shows the collector sheet (high voltage electrode plate) of the dust collecting part which concerns on embodiment of this invention. It is a graph explaining the discharge characteristic about the collector sheet (high voltage electrode plate) of the dust collecting part in the electrostatic precipitator which concerns on embodiment of this invention. It is a figure explaining the rib in the electrostatic precipitator which concerns on embodiment of this invention, (a) is the figure explaining the gap between the notch of the collector sheet and the conventional rib, (b) is the figure of the collector sheet. It is a figure explaining the rib which eliminated the gap with the notch.

Hereinafter, embodiments for carrying out the present invention (hereinafter, referred to as “embodiments”) will be described in detail with reference to the accompanying drawings. The same elements are numbered the same throughout the description of the embodiment.

(Overall configuration of electrostatic precipitator)
First, the overall configuration of the electrostatic precipitator 1 will be described with reference to FIG. As shown in FIG. 1, the outer case front portion 2 and the outer case back portion 3 are joined to each other, and the GND plate 4 and the HV plate 6 as the charged portion 1A sandwich the inner case front portion 5 inside. Is placed. In FIG. 1, for convenience of explanation, the parts, the charged portion 1A, and the dust collecting portion 1B that should be inside the outer case front portion 2 and the outer case back portion 3 are outside the outer case front portion 2 and the outer case back portion 3. Although it is disassembled, it is actually housed inside the outer case front portion 2 and the outer case back portion 3.

Ribs 14 are provided on the back surface portion 7 of the inner case so as to extend in the vertical direction, and the HV (Hi Voltage) sheet 8 (high voltage electrode plate), which is a collector sheet as the dust collecting portion 1B, is a rib for the high voltage electrode plate. It is fixed to 14a, and the GND sheet 11 (collection electrode plate) is fixed to the collection electrode plate rib 14b. The HV electrode 9 and the HV electrode cover 10 are provided on the right side of the HV sheet 8 in the drawing. A GND electrode 12 and a GND electrode cover 13 are provided on the left side of the GND sheet 11 in the drawing. In the following description, the ribs will be referred to as ribs 14, and the ribs will be referred to as high-voltage electrode plate ribs 14a and collection electrode plate ribs 14b when individually described. By applying a voltage between the HV sheet 8 and the GND sheet 11, an electrostatic force is formed between the HV sheet 8 and the GND sheet 11. The collector sheet is formed in a plate shape.

The ventilation direction is from the front surface portion 2 of the outer case to the back surface portion 3 of the outer case. Particles such as dust contained in the air flowing into the electrostatic precipitator 1 are charged by the electric discharge between the GND plate 4 and the HV plate 6 arranged in the charging unit 1A. Then, the particles charged by the charged portion 1A are collected by the GND sheet 11 due to the electrostatic force formed between the HV sheet 8 and the GND sheet 11 arranged in the dust collecting portion 1B.

The dust collecting unit 1B will be further described with reference to FIGS. 2, 3 and 4. FIG. 2 shows the appearance of the dust collecting unit 1B of the electrostatic precipitator 1, and FIG. 3 shows the internal structure of the dust collecting unit 1B. As shown in FIG. 2, in the dust collecting portion 1B, the HV sheet 8 and the GND sheet 11 are arranged on the back surface portion 3 of the outer case so that their respective longitudinal directions are in the left-right direction in the drawing, and the HV sheet is arranged in the vertical direction in the drawing. The surface 8b of 8 and the surface 11a of the GND sheet 11 and the surface 8a of the HV sheet 8 and the surface 11b of the GND sheet 11 are alternately laminated and arranged so as to face each other. When the outer case back surface 3 is removed, as shown in FIG. 3, ribs 14 are provided inside the outer case so as to project from the inner case back surface 7 toward the front side in the drawing.

In the rib 14, the rib 14a for the high-voltage electrode plate for fixing the HV sheet 8 and the rib 14b for the collecting electrode plate for fixing the GND sheet 11 are alternately arranged, and here, the rib 14a for the high-voltage electrode plate is arranged. An example is shown in which three ribs 14b for collecting electrode plates are provided. The HV electrode 9 is in contact with the right end of the HV sheet 8 in the drawing, and the GND electrode 12 is in contact with the left end of the GND sheet 11 in the drawing.

Here, the fixing relationship between the HV sheet 8 and the GND sheet 11 and the ribs 14a for the high-voltage electrode plate and the ribs 14b for the collection electrode plate will be described with reference to FIG. FIG. 4A is a cross-sectional view of the rib 14a for the high-voltage electrode plate fixing the HV sheet 8 when cut in the vertical direction and viewed from the horizontal direction. FIG. 4B is a cross-sectional view of the collecting electrode plate rib 14b fixing the GND sheet 11 when cut in the vertical direction and viewed from the horizontal direction. As shown in FIG. 4A, the HV sheet 8 is fixed by being inserted into the slit 14a1 of the rib 14a for the high-voltage electrode plate (solid line in the figure), and the GND sheet 11 has a second notch. Since the portion Cb does not come into contact with the rib 14a, it is not fixed to the rib 14a for the high-voltage electrode plate (indicated by a broken line in the figure). On the other hand, as shown in FIG. 4 (b), the GND sheet 11 is fixed by being inserted into the slit 14b1 of the collection electrode plate rib 14b (solid line in the figure), and the HV sheet 8 is the first. Since it does not come into contact with the rib 14b due to the notch Ca of the above, it is not fixed to the rib 14b for the collecting electrode plate (indicated by a broken line in the figure). The structure in which each sheet is not fixed by the ribs 14 having different potential polarities will be described later.

(Collector sheet)
Next, the collector sheet 20 will be described in detail. The collector sheet 20 is a pair of an HV sheet 8 (high voltage electrode plate) and a GND sheet 11 (collection electrode plate). Both the HV sheet 8 and the GND sheet 11 are asymmetrical. Both have the same shape and size, and are arranged so as to face each other in an inverted form after the left and right sides are reversed. In the following, when each sheet is described collectively, it is referred to as a "collector sheet", and when it is described individually, it is referred to as an "HV sheet" or a "GND sheet".

FIG. 5 shows a conventional collector sheet 20. The collector sheet 20 is formed of a rectangular sheet, and notches C are provided on both sides of the sheet in the lateral direction to avoid contact with ribs 14 having different polarities when attached to the electrostatic precipitator 1. Has been done. Here, an example is shown in which notches C are provided at four locations on one side in the lateral direction and at three locations on the other side. Ends (parts indicated by length L3) are provided at both ends of the attachment portion (part indicated by length L2) to which a large amount of dust or dust adheres, and electrodes are provided at the lower end in the figure. Is pasted.

Here, as described above, the collector sheet 20 of the dust collecting portion 1B of the two-stage electrostatic precipitator 1 forms an electrostatic field to collect dust, but the notch portion C of the collector sheet 20 is used. When a discharge is generated from the corner portion of the rib 14 to the rib 14, the sheet potential is lowered due to the discharge current, a predetermined electric field strength cannot be obtained, and there is a problem that the dust collecting performance is lowered. On the other hand, as shown in FIG. 6, in order to avoid electric discharge, there is a technique of forming a portion of the collector sheet 20 where the electric field is concentrated into an R shape (arc shape), and the corner portion 21 of the collector sheet 20 is rounded. It was made into a shape (arc shape).

On the other hand, in order to secure the insulation between the HV sheet 8 and the GND sheet and 11, both sheets are provided with notches C (first notch Ca and second notch Cb). The HV sheet 8 is fixed to the rib 14a for the high-voltage electrode plate, and the GND sheet 11 is fixed to the rib 14b for the collection electrode plate. Normally, the cross-sectional shapes of the high-voltage electrode plate rib 14a and the collection electrode plate rib 14b are substantially rectangular.

The larger the curvature of the corner portion 21 of the notch C, the more difficult it is to discharge, but on the other hand, the area of the collector sheet 20 becomes smaller and an electric field is formed between the HV sheet 8 and the GND sheet 11. The area to be discharged becomes smaller.

However, if the R shape is increased, the size of the electrostatic precipitator 1 is increased, and the gap between the notch C and the rib 14 is also increased. As a result, of the air passing between the HV sheet 8 and the GND sheet 11, the proportion of the air passing through the spaces above and below the notch C where the electric field is not generated becomes large, so that the dust collection performance is rather large. Will lead to a decrease in. Therefore, in the present embodiment, as shown in FIG. 6, the R shape of the opening of the notch C of the collector sheet 20 is increased, and as shown in FIG. 8, the cross section of the rib 14 for fixing the collector sheet 20 is increased. By making the shape follow the R shape of the opening of the notch C of the collector sheet 20, the dust collection performance does not deteriorate due to the increase in the ratio of passing through the above-mentioned portion without an electric field. It is something to do.

First, with reference to FIG. 7, how the size of R of the opening of the notch C changes the discharge current flowing during discharge with respect to the rib 14 which affects the dust collection performance will be described.

The influence of the size of R of the opening of the notch C was tested as follows. The collector sheet 20 used for the test is as follows. As the HV sheet 8, a sheet composed of a volume low efficiency ρv = 3 * 10 9th power Ωcm was prepared. The shape of the HV sheet 8 is rectangular (long side 84 mm, short side 34 mm, thickness 0.4 mm), and protrusions for attaching electrodes are provided at one of the four corners. Then, a corner to be tested is provided in the opposite corner on the short side when viewed from the protrusion, and as an insulator so as to cover the two corners on the opposite short side on the long side when viewed from the protrusion and the corner. A vinyl tape was attached.

On the other hand, as the GND sheet 11, a sheet having a volume low efficiency ρv = 200Ωcm was prepared. The shape of the GND sheet 11 is also rectangular (long side 216 mm, short side 34 mm, thickness 0.4 mm), and a protrusion for attaching an electrode is provided at one of the four corners opposite to the HV sheet 8 on the long side. Provided. The GND sheet 11 was used as it was without processing and without providing corners.

Using the HV sheet 8 and the GND sheet 11 prepared as described above, the test was conducted according to the following procedure.
(1) The corner 21 of the HV sheet 8 is arranged so as to face the long side of the GND sheet 11 at a distance of 2 mm. At this time, the vinyl tape of the HV sheet 8 faces the GND sheet 11.
(2) Electrodes are attached to the protrusions of the HV sheet 8 and the GND sheet 11, and a voltage is applied between the two sheets by a high-voltage power supply.
(3) The return current from the GND sheet 11 is measured in the current measurement mode of the insulation resistance tester.
(4) Obtain the applied voltage when the current changes significantly due to discharge.

The following measuring instruments were used.
・ High-voltage power supply: Made by Matsusada Precision (6kV / 0.5mA max), positive electrode, Vunitor, input 24VDC with Immunotor
-Oscilloscope: Texio Technology DCS 12204E
-Current measurement: YHP insulation resistance tester high resistance meter 4329A

Based on the above preparation, the R of the corner 21 provided on the HV sheet 8 was changed in the range of 1 to 15 mm, and the change in the applied voltage Vi at which the discharge current i was 50 nA was measured. The results are shown in FIG. The conditions at the time of the test were a temperature of 26 ° C. and a humidity of 50%.

As shown in FIG. 7, as R increases, the applied voltage Vi that starts discharging to the rib 14 increases, and when R becomes 7 mm, the applied voltage Vi increases by about 1 kV as compared with the case where R is 1 mm. Can be raised. When R exceeds 10 mm, the applied voltage Vi becomes almost constant. As described above, the effect of increasing the applied voltage Vi is sequentially obtained from the case where R is 1 mm, but from the viewpoint of obtaining a remarkable effect of increasing R by about 1 kV, R is preferably in the range of 7 mm to 10 mm.

Next, the cross-sectional shape of the rib for fixing the collector sheet 20 will be described with reference to FIG. 8 and FIGS. 5 and 6 as appropriate.

The main specifications of the collector sheet 20 shown in FIG. 5 or FIG. 6 are as follows, for example. Of course, this embodiment is not limited to these specifications.
・ Overall length L1: 188 mm
・ Length of rectangular part L2: 162mm
・ Length of both ends L3: 13mm
・ Width W1: 18.5 mm
・ Pitch between notches P: 23 mm (× 6 pitch = 138 mm)
・ Notch width Cl: 6 mm
・ Depth of notch Cw: 7mm

When the collector sheet 20 is set according to the above specifications, the radius of the opening of the notch C of the collector sheet 20 is set to, for example, 7 mm, and the cross-sectional shape of the rib 14 remains rectangular, FIG. 8 (a) shows. The area of the gap on one side between the hatched notch C and the rib 14 is 10.5 mm ² . Looking at this for the entire collector sheet 20, 10.5 mm ² x 2 (both sides of the rib) x 7 (total number of notches) x 2 (a pair of HV sheet 8 and GND sheet 11), so one set of collector sheets The total area of the gap is 294 mm ² . Since the total effective sheet area of the collector sheet 20 is 2409 mm ² , the total area of the gap corresponds to 12.2%.

Here, as shown in FIG. 8B, if the cross-sectional shape of the rib 14 is formed to follow the shape of R7 mm of the notch C, the air passing through the portion where there is no electric field is removed by the rib 14. Since it is forcibly guided on the collector sheet 20 having an electric field, the dust collection performance can be improved.

Since the cross section of the rib 14 is increased, the rigidity of the rib 14 is increased, and it is also possible to suppress the leakage current generated when the strength is maintained by connecting the ribs to each other.

Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and modifications are made within the scope of the gist of the present invention described in the claims. It can be changed.

1 ... Electrostatic precipitator 1A ... Charged part 1B ... Dust collecting part 2 ... External case front part 3 ... External case back part 4 ... GND plate (charged part)
5 ... Inner case front part 6 ... HV plate (charged part)
7 ... Inner case back surface 8 ... HV sheet (collector sheet. High-pressure electrode plate for dust collecting part)
9 ... HV electrode 10 ... HV electrode cover 11 ... GND sheet (collector sheet. Dust collecting electrode plate)
12 ... GND electrode 13 ... GND electrode cover 14 ... Rib 14a ... Rib 14b for high-voltage electrode plate ... Rib C for collection electrode plate C ... Notch Cl ... Notch width Cw ... Notch depth R1 ... R shape (1 mm) )
R7 ... R shape (7 mm)

Claims (1)

A charged part that charges the dust contained in the air,
A dust collecting unit for collecting dust charged by the charged unit is provided.
The dust collecting portion includes a plate-shaped high-voltage electrode plate, a plate-shaped collecting electrode plate, a rib for a high-voltage electrode plate, and a rib for a collecting electrode plate.
The surfaces of the high-voltage electrode plate and the surface of the collection electrode plate are alternately arranged in parallel with each other facing each other.
The high-voltage electrode plate is fixed to the rib for the high-voltage electrode plate and has a first notch portion for avoiding contact with the rib for the collection electrode plate.
The collection electrode plate is fixed to the collection electrode plate rib and has a second notch portion for avoiding contact with the high voltage electrode plate rib.
A corner portion on the opening side of at least one of the first notch and the second notch is formed in a rounded shape, and at least one of the corresponding rib for the collecting electrode plate and the rib for the high voltage electrode plate. Is formed so as to follow the rounded shape of the corner portion.

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