JPH06114287A - Method and device for removing dust sticking to electrostatic precipitator - Google Patents

Abstract

PURPOSE:To easily and rapidly remove the dust sticking to the electrostatic precipitator having dust collecting electrode plates in the air flow passing in the precipitator with a simple appliance, thereby facilitating the maintenance by applying the high-frequency vibrations of the vibration frequencies within the range set by specific equations to the dust collecting electrode plates. CONSTITUTION:This electrostatic precipitator has a gate-shaped frame 1 in the flow passage of the dust-contg. air flow and the dust collecting electrodes 2 and discharge electrodes 3 therein and is constituted by mounting high-frequency vibrators 4 respectively to brackets 1a provided on the top end wall of the frame 1 in such a manner that the high-frequency vibrations from the high-frequency vibrators 4 can be transmitted to the dust collecting electrode plates 2. The precipitator is so constituted that the high-frequency vibrations of the vibration frequencies within the range of y1, y2 set by the equation I, the equation II are applied to the dust collecting electrode plates 4 by setting vibration frequencies by a high frequency transmitter 4a. In the equations, y1 is the lower limit vibration frequency; y2 is the upper limit vibration frequency, (x) is the grain size of the dust.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric precipitator provided in various kinds of dust removing equipment, and more particularly to a method and an apparatus for removing dust adhering to a dust collecting electrode plate.

[0002]

2. Description of the Related Art Electric dust collectors have been widely used as dust removing equipment. This electrostatic precipitator has a configuration in which a discharge electrode and a dust collecting electrode plate are provided in a flow path through which an air flow containing dust passes, and the dust is charged to adhere to the dust collecting electrode plate for recovery. That is the basis.

In such an electrostatic precipitator, most of the dust in the air stream adheres to and accumulates on the dust collecting electrode plate as the dust collection progresses. When the amount of dust attached increases, the dust collection efficiency decreases, so it is necessary to regularly remove the attached dust.

As a method of removing such adhering dust, a hammering mechanism for hitting the dust collecting electrode plate has been mainly adopted. In this hammering mechanism, the dust collecting electrode plate is hit with a hammer to remove the attached dust.

However, depending on the type of dust, it is not possible to remove and remove it sufficiently with only such a mechanical striking force. Particularly, for fine dust particles adhering to the dust collecting electrode plate on the output side of the dust collector, There is a big tendency.

On the other hand, in order to solve such a problem, for example, as described in Japanese Utility Model Laid-Open No. 63-107742, a scraper is moved along a dust collecting electrode plate to mechanically remove the attached dust. There is something to force peeling. In addition, as disclosed in Japanese Utility Model Laid-Open No. 59-176661, there is also one that is provided with a rotating brush that can move up and down along a dust collecting electrode plate and sweeps the attached dust by this brush.

[0007]

However, in the case of using such a scraper or a brush, in addition to providing these mechanical parts, a mechanism for moving each along the dust collecting electrode plate is required. For this reason, the attached device for removing the adhering dust becomes considerably complicated, and the device itself operates in a bad dust atmosphere, so that many troubles occur and the working environment during maintenance is bad. Further, since a moving space for the brush and scraper is required, it may interfere with the dust collecting space and reduce the efficiency thereof.

Further, since the brush and scraper move between the discharge electrode to which a high voltage is applied and the dust collecting electrode, the larger the equipment, the longer the working time and the lower the operating rate. Then, during the period of the work of removing the adhered dust, it is necessary to turn off the charge on the electrodes, and even if such a removing work is simultaneously performed during the operation, the reduction of the dust collection efficiency cannot be avoided.

As described above, in the conventional removal of the adhered dust, there is a problem in that the removal time is long and the equipment is complicated because maintenance depends on mechanical peeling.

The problem to be solved in the present invention is to more quickly remove the adhering dust from the dust collecting plate of the electrostatic precipitator and to facilitate maintenance and inspection.

[0011]

According to the present invention, in an electrostatic precipitator provided with a dust collecting electrode plate that is exposed to a passing air flow, dust that has adhered to the dust collecting electrode plate is separated in its aggregated state. It is characterized in that a high frequency vibration of a vibration frequency is given.

Further, the attached dust removing device is characterized in that the dust collecting electrode plate is connected to a high frequency vibrator capable of transmitting high frequency vibration to the dust collecting electrode plate.

[0013]

In general, with respect to the easiness of handling of the powder, there is a correlation between the gravity W of the powder and the adhesive force F, and the larger W is than F, the easier the handling is. Here, W is proportional to the cube of the particle diameter, and F is proportional to the cube of the particle diameter. Therefore, as the particle size becomes smaller, F becomes dominant and the powder becomes sticky,
It hardens and becomes difficult to handle.

FIG. 9 shows the approximate relationship between the gravity and the adhesive force. In this figure, the particle diameter of the intersection D _C at which the adhesive force becomes larger than gravity and becomes dominant, is considerably different depending on the properties of the powder, but is about 30 to 50 μm according to literature and experiments. For this reason, when dust in the range of the particle size or less is collected by the dust collecting electrode, it is difficult to peel it off by a commonly used hammering.

According to the present invention, high acceleration is applied to the dust collecting electrode plate by applying high-frequency vibration to the dust collecting electrode plate, and as a result, the fine dust particles have a force of f = (W / g) · α. Upon receiving (W is the weight of particles, g is the acceleration of gravity), and when this f becomes the adhesion force F <f, the fine dust separates from the dust collecting electrode plate and begins to peel (fall).

That is, in the conventional mechanical vibration (e.g., an eccentric motor), the vibration frequency is about 40 Hz at the maximum. It is difficult to peel off particles having a particle size of 30 μm or less, which have a large adhesive force, from the dust collecting electrode plate at such a frequency.

When high frequency vibration is applied to the dust collecting electrode plate as described above, the vibration is also transmitted to the dust layer adhering to the dust collecting electrode plate, and this layer is fluidized and can be separated. If the frequency range of the high frequency vibration is set so as to be separated from the dust collecting electrode plate in the form of cake in which dust is aggregated, the adhered dust can be collected as an aggregate without scattering. .

In order to apply high frequency vibration to the dust collecting electrode plate, a high frequency vibrator may be mechanically connected to a part of the dust collecting electrode plate, whereby the vibration is propagated to the whole dust collecting electrode plate. You can Therefore, it is not necessary to continuously change its operating position like a scraper for removing adhered dust, the space required for operating the device is reduced, and the degree of interference with the dust collection space is also suppressed. .

[0019]

1 is an external view showing an outline of an electrostatic precipitator of the present invention, and FIG. 2 is a schematic vertical sectional view as seen in a flow direction of an air flow.

The electrostatic precipitator is provided with a gate-shaped frame 1 installed in the flow path of an air stream containing dust, and in the illustrated example, a total of eight dust collecting electrode plates 2 and nine discharge electrodes 3 are provided therein. I have it. The dust collecting electrode plate 2 has a flat plate shape and is suspended from the upper end of the frame 1 so as to be parallel to the flow of the air flow. Further, the discharge electrodes 3 are arranged between the dust collecting electrode plates 2 and at both ends, and are fixed at predetermined positions by using the frame 1. Then, like the conventional dust collector, the dust collecting electrode plate 2 and the discharge electrode 3 are connected to respective power sources, and the dust in the air stream is charged by the application of a voltage so that the dust collecting electrode plate 2 and the discharge electrode 3 can be attached to the dust collecting electrode plate 2. .

In FIG. 2, a bracket 1a is provided on the upper end wall of the frame 1 in correspondence with the position of each dust collecting electrode plate 2,
The high frequency vibrators 4 are attached to the brackets 1a, respectively. Each of these high-frequency vibrators 4 has 1
The dust collecting electrode plates 2 are connected one by one by a mechanical means such as a bolt 2a so that the high frequency vibration from the high frequency oscillator 4 can be transmitted to the dust collecting electrode plate 2. Note that FIG. 3 shows a schematic vertical sectional view taken along the line AA of FIG.

The high-frequency oscillator 4 uses, for example, a piezoelectric element, and is connected to the high-frequency oscillator 4a provided in the controller room of the electrostatic precipitator by lead wires 4b and 4c. By setting the vibration frequency by the high-frequency oscillator 4a, it is possible to apply high-frequency vibration corresponding to the nature and amount of dust to the dust collecting electrode plate 2.

Further, in order to prevent the dust collecting electrode plates 2 to which high frequency vibration is applied from contacting each other due to the vibration, a spacer 5 is incorporated as shown in FIG. These spacers 5 keep the distance between the dust collecting electrode plates 2 constant, and are attached so as not to hinder vibration.

In the above structure, when an air stream containing dust passes through the frame 1, the dust is charged by the discharge from the discharge electrode 3 to which a high voltage is applied,
It is adsorbed to the dust collecting electrode plate 2 to which a voltage is applied so as to have a polarity different from that of this.

In order to remove dust that has adhered to and accumulated on the dust collecting electrode plate 2, the high frequency oscillator 4a vibrates the high frequency oscillator 4, and the high frequency vibration is transmitted to the dust collecting electrode plate 2. As a result, the dust collecting electrode plate 2 whose upper end is connected to the high frequency vibrator 4 and is suspended also vibrates at a high frequency, and the vibrating force due to the vibration is used to shake off the attached dust.

By applying high frequency vibration to the dust collecting electrode plate 2 in this manner, the attached dust can be instantly removed. And, fine particles of small particles among the adhered dust have a strong adherence and cohesiveness and are difficult to be separated only by vibration of impact by simple hammering, but if high frequency vibration is used, its vibration characteristics promote fluidization of the adhered dust. By doing so, it is possible to easily peel and remove. Further, the charged dust has strong adhesiveness, but can be quickly removed for the same reason.

By using the vibration imparted by the high frequency vibrator 4, the time required for removing the adhering dust is significantly shortened as compared with the case where a scraper or a brush is run along the dust collecting electrode plate 2. Therefore, it is possible to collect dust without affecting the flow of the air flow even during the dust collection operation, and the processing efficiency can be improved. Further, it is not necessary to provide a space for the scraper or the brush to run between the dust collecting electrode plates 2, and it is possible to dispose them close to each other, for example, about several cm, and the dust collecting efficiency is improved by increasing the dust collecting area. To do. Further, since a movable member such as a scraper or a brush and a mechanism for driving the movable member are not required, abrasion and other troubles do not occur even in a bad environment including dust.

FIG. 4 is a schematic view of the main part of another embodiment, and is a view as seen in the flow direction of the air flow as in FIG.

In this example, the bracket 1a of the frame 1
The dust collecting electrode plate 2 is directly connected to the dust collecting electrode plate 2 by a bolt 2b, and the high-frequency oscillator 4 is fixed to the dust collecting electrode plate 2 substantially at the center in the height direction.

In this way, the high frequency oscillator 4 is attached to the dust collecting electrode plate 2
2 can be applied to the dust collecting electrode plate 2 by the high frequency oscillator even if it is provided in the middle of the height direction of
As in the above example, the adhered dust can be quickly peeled and removed.

Further, the high frequency oscillator 4 may be provided at the lower end portion of the dust collecting electrode plate 2 or other portions, and in any case, the high frequency vibration may be applied to the dust collecting electrode plate 2.

In FIG. 5, a large number of dust collecting electrode plates 2 are attached to the vibration transmitting rod 7, and one high frequency vibrator 4 connected to one end of the vibration transmitting rod 7 simultaneously removes a large number of dust collecting electrode plates 2. This is an example of vibrating, and only one high-frequency oscillator 4 is required and the structure is simple. In this example, the dust collecting electrode plate 4 is attached to the antinode portion of the vibration of the vibration transmitting rod 7 having the largest amplitude according to the frequency.

Further, FIG. 6 shows two vibration transmission rods 7a and 7b.
This is an example in which the dust collecting electrode plates 2 are attached to the respective.

The dust collecting electrode plates 2 attached to the vibration transmission rods 7a and 7b respectively have the same vibration transmission rods 7a and 7b as described above.
The vibration transmitting rods are attached to the abdomen of the vibrations and are combined by shifting the vibration transmitting rods 7a and 7b in the axial direction by 1/2 wavelength of the vibration wavelengths of the respective vibration transmitting rods 7a and 7b. Configuration is possible. It is of course possible to attach dust collecting electrode plates to each of the three vibration transmission rods. In this case, a combination of shifting the vibration wavelength of the vibration transmission rods by 1/3 wavelength in the axial direction may be used.

Further, FIG. 7 shows two dust collecting electrode plates 6a and 6b.
In this example, each is bent in a loop shape and is hung on the frame 1. One end of each of the dust collecting electrode plates 6a and 6b is connected to both ends of the frame 1, and the dust collecting electrode plates 6a and 6b are hung on the roller 1b and constrained by the frame 1 with a certain degree of freedom.

The high frequency oscillator 4 held by the bracket 1c is assembled between the dust collecting electrode plates 6a and 6b,
Similar to the above example, the dust collecting electrode plates 6a and 6b are connected to each other so that high frequency vibration can be transmitted.

Also in this example, the high frequency vibration by the high frequency oscillator 4 is transmitted to the dust collecting electrode plates 6a, 6b, and vibrates at a uniform high frequency up to the connection point with the frame 1 at both ends, and the above examples Similarly, the adhered dust can be quickly removed and removed.

Here, when the dust collecting electrode plate 2 is vibrated by the high-frequency vibrator 4, it is preferable that the cake-like particles of the adhered dust are separated from the entire surface of the dust collecting electrode plate 2 at once. That is, although it is a condition related to the particle size of dust, if the vibration frequency is small, sufficient fluidization cannot be obtained to separate the dust, while if the vibration frequency is too large, the dust is completely fluidized. In the former case, it is impossible to remove the dust at a low frequency, and in the latter case, the dust is fragmented and scattered again.

From the above, it is necessary to determine an appropriate high frequency vibration band in order to separate the adhered dust into a cake shape. FIG. 8 is a diagram for determining an appropriate frequency displayed according to the relationship between the particle diameter and the vibration frequency,
It is obtained by experiment.

If the frequency is selected so that the particle size and the frequency of the dust have a corresponding relationship in the separation area avoiding the immobilization area and the fluidization area shown in this figure, the separation is impossible or scattering occurs. It is possible to brush off the attached dust from the surface of the dust collecting electrode plate 2 in the form of cake.

A method of applying mechanical vibration to the dust collecting electrode by using an eccentric motor or the like to remove the adhered dust is described in, for example, Japanese Utility Model Publication No. 51-3096. However, the vibration described in this publication has a frequency of 5
It is a few Hz of -40 Hz and the amplitude is about 5 to 10 mm. With this level of vibration, as shown in FIG. 8, when the particle size is 50 μm or less, it becomes a non-moving region and the adhered dust cannot be separated. On the other hand, the frequency and amplitude of the present invention are in the range of 500 Hz to several tens of kHz and the amplitude is about 3 to 20 μm, which is significantly different from the conventional one.

[0042]

According to the present invention, the attached dust can be instantly removed only by applying high frequency vibration to the dust collecting electrode plate.
As compared with the case of using a scraper, a brush or the like, the removal time is remarkably shorter, and if the frequency is set according to the particle size of dust, it is possible to remove according to the dust collection condition.

Further, since a movable member such as a scraper and a driving mechanism therefor are not required, the equipment is simplified and maintenance and inspection are facilitated. Further, since only the high frequency vibrator is incorporated, the distance between the dust collecting electrode plates can be narrowed to increase the dust collecting surface area, and the dust collecting efficiency can be improved.

[Brief description of drawings]

FIG. 1 is an external perspective view showing an outline of an electrostatic precipitator of the present invention.

FIG. 2 is a diagram showing the outline of the internal structure of the electrostatic precipitator as seen in the direction of air flow.

FIG. 3 is a schematic view showing a mounting structure of a dust collecting electrode plate to a bracket as seen from the line AA of FIG.

FIG. 4 is a diagram showing an example in which high-frequency vibrators are provided at intermediate portions in the height direction of the dust collection electrode plate.

[Fig. 5] A large number of dust collecting electrode plates are arranged on the vibration transmission rod.
It is a figure which shows the example which gives a vibration simultaneously by one high frequency oscillator, Comprising: (a) of the same figure is a schematic front view shown with the vibration wavelength of a vibration transmission rod, (b) of the same figure is of the same figure (a). BB
FIG.

FIG. 6 is an example in which the distance between the dust collecting electrode plates on each of the two vibration transmission rods is half the vibration wavelength of the vibration transmission rod, and FIG. 6 (a) is a schematic front view thereof. (B) of the same figure is a CC line arrow line view of the same figure (a).

FIG. 7 is a schematic diagram showing an example in which two dust collecting electrode plates are arranged in a loop and a single high-frequency oscillator applies vibration.

FIG. 8 is a diagram for giving a suitable vibration frequency with respect to a particle size for peeling the adhered dust into a cake.

FIG. 9 is a diagram showing the correlation between the gravity of powder and the adhesive force.

[Explanation of symbols]

 1 frame 2 dust collecting electrode plate 3 discharge electrode 4 high frequency oscillator 4a high frequency oscillator 5 spacers 6a, 6b dust collecting electrode plate 7 vibration transmission rod

Claims (2)

[Claims] 1. An electrostatic precipitator provided with a dust collecting electrode plate exposed to an air flow passing therethrough, wherein the dust collecting electrode plate has a vibration frequency within a range of y ₁ and y ₂ set by the following equation. A method for removing adhered dust in an electrostatic precipitator characterized by applying high-frequency vibration. [Equation 1] [Equation 2] y: vibration frequency, x: particle size of dust (μm) 2. An electrostatic precipitator provided with a dust collecting electrode plate exposed to an air flow passing therethrough, wherein the dust collecting electrode plate is provided with a high frequency vibrator capable of transmitting high frequency vibration to the dust collecting electrode plate. An adhering dust removing device in an electrostatic precipitator characterized by being connected.