JP3456959B2 - Dust collector - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention collects atmospheric dust, indoor dust, dust, etc. in the air conditioning and industrial fields, and
Despite being an electric dust collector, charged dust is neutralized from the outlet of the dust collector, and corona discharge is not used, and ozone is not generated. The present invention relates to a dust collector that prevents dirt.

[0002]

2. Description of the Related Art Conventionally, an electric dust collector of this type is known, for example, one disclosed in Japanese Patent Laid-Open No. 6-31200.

The dust collecting device will be described below with reference to FIG.

As shown in the figure, the charging unit 101 comprises a discharge electrode A102 consisting of a discharge line and a ground electrode plate A103, and a voltage application electrode plate 105 is provided on the downstream side of the charging unit 101.
A dust collecting portion 104 including a ground electrode plate B106 is provided. Usually, in the charging unit 101, the discharge electrode A10
5 to 15 kV between the ground electrode plate A 103 and the ground electrode plate A 103 connected to the ground, and the voltage applying electrode plate 1 of the dust collecting unit 106.
05 and a ground electrode plate B106 connected to the ground so that a potential difference of 2 to 6 kV is generated.
And a DC voltage is applied to the voltage applying electrode plate 105 to stabilize the high voltage power supply 1
07 is applied. And the blower fan 108
As a result, air containing dust is taken into the dust collector.

In the above structure, when air containing dust is introduced into the dust collector, the charging electrode 101 causes the discharge electrode A
Corona discharge occurs between 102 and the ground electrode plate A103, and air ions ionized by the corona discharge adhere to the dust of air passing therethrough to be charged.
Voltage application electrode plate 105 and earth electrode plate B106 in the dust collecting section
In addition, although no corona discharge is generated, an electric field is generated, and the charged dust is removed by being attached to the voltage application electrode plate 105 or the ground electrode plate B106 by the force of the electric field. The air is blown out in a clean state.

Further, in the above-mentioned conventional example, a linear electrode is shown as the discharge electrode, but the same applies even if a needle-shaped electrode is used instead of the linear electrode, and the tip of the needle-shaped electrode and the ground electrode plate A1.
During 03, corona discharge occurs and dust is collected by the same mechanism.

In such a conventional dust collecting apparatus, all the dust charged in the charging section is not collected in the dust collecting section. For example, if the removal rate is 80%, the remaining 20% remains. Uncollected charged dust is released indoors. The charged dust has a property of easily adhering to the wall inside the room and the like. In particular, household electric appliances such as TVs are charged and easily stick to them. Also, it is considered that the wall is not normally charged, but when air flows to the wall surface due to air blow, static electricity is generated due to the friction, and the wall surface is also charged, and the wall surface is also in a state where charged dust is likely to adhere. .

Further, even if the dust collection efficiency is close to 100%, the dust once collected in the dust collection section may be separated from the dust collection section for some reason, and re-scattered, and the re-scattered dust is also charged. ing. Even if the amount of charged dust is small, only ions (such as air ions) are emitted, and the ions adhere to the surrounding dust to become charged dust. Therefore, even if the electric dust collector has a high dust collecting efficiency, dust that has re-scattered or dust combined with ions adheres to the blow-out side wall or the like, causing dirt.

Conventionally, as a method of preventing such dirt due to charged dust, there is a method of electrically canceling the charge of the charged dust with a charge of opposite polarity, which is called neutralization of the charged dust. Define. As a method of neutralizing charged dust and preventing dirt, a method of arranging positive and negative polarity dust collectors in parallel and mixing electrically charged dust of each polarity blown out from the dust collector to electrically neutralize each other ( Japanese Patent Laid-Open No. 53-64878), a discharge unit having an opposite polarity is provided every other stage behind the dust collecting unit, and the dust charged by the charging unit in the preceding stage and the dust having the opposite polarity are generated and mixed. Method of coarsening dust (Japanese Patent Laid-Open No. 55-1
No. 57348), voltages of different polarities are alternately applied to the discharge electrodes arranged in parallel in the charging part, and the charged dust of each polarity which comes out of the dust collecting part without being able to collect the dust is mixed with each other. The voltage applying electrode plate of the dust collecting part is exposed and not insulated, and the voltage opposite to that of the charging part discharge line is applied to the dust collecting part applying electrode plate to reverse the charging part. Method of neutralizing charged dust by causing corona discharge having the above-mentioned polarity in the dust collecting portion (see JP-A-8-898).
Measures have been studied by the Japanese Patent No. 42).

[0010]

In such a conventional method, it can be used in a large system in which the dust collectors are arranged in parallel, but it is difficult to introduce it when there is only one dust collector. If the charged dust charged in each polarity is not mixed completely, the wall surface may be polluted as it is without being neutralized.Since corona discharge is occurring, the discharge current is large and ozone is generated. It cannot be said that the structure is such that sufficient corona discharge occurs in the dust part, and since the application electrode plate of the dust collection part is used in a non-insulated state, it is necessary to make a structure that does not contact the ground electrode plate, making it difficult to manufacture. Does not become compact. Further, as a method of releasing ions common to the space, since corona discharge is used, there is a problem that the discharge current is large and ozone harmful to the human body is generated. What is needed is a dust collector that can be used in any type of dust collector, does not rely on mixing dust particles of different polarities, and has a small discharge current that can neutralize charged dust particles with little ozone generation. ing.

Further, in the dust collector provided with the charge neutralizing means, when the charge amount of the charged dust blown out from the dust collecting part is not constant and changes, the charge neutralizing means is most suitable in accordance with the changed charge amount. There is a problem that it is necessary to generate a large amount of ions, and there is a demand for a charge neutralizing means capable of generating an optimal amount of ions of the opposite polarity in accordance with the charge amount of charged dust.

Further, in the dust collector provided with the charge neutralizing means, after the charged dust has passed through the charge neutralizing means, it is confirmed whether or not the charged dust is actually neutralized, and the charge neutralizing means is effective. There is a problem that it is necessary to monitor whether or not it is working properly, and it is required to be able to confirm the neutralization of the charged dust by detecting the polarity and charge amount of the dust blown from the charge neutralization means.

Further, in the dust collector provided with the charge neutralizing means, after the charged dust has passed through the charge neutralizing means, it is confirmed whether or not the charged dust is actually neutralized. Has a problem that it is necessary to always neutralize the charged dust by optimally controlling the voltage setting of the charge neutralization means in real time. In order to keep the charged dust in the neutralized state at all times, It is required to control the neutralization means.

Further, in an electric dust collector used for treating dust in road tunnels and factories, when the electric resistance of dust is low, the treated dust accumulated in the dust collecting portion causes a short circuit between electrodes. However, there is a problem that it becomes a spark and impacts the electrode plate, and dust accumulated on the electrode plate is re-dispersed in a charged state, and even when a large amount of re-dispersion occurs due to sparks, the wall surface behind the dust collector It is required not to pollute.

The present invention solves such a conventional problem and can be used for any type of dust collector, does not rely on mixing dusts having different polarities, and has a small discharge current, which is harmful to the human body. An object of the present invention is to provide a dust collector that can neutralize charged dust with almost no generation of ozone.

It is another object of the present invention to provide a dust collecting apparatus capable of neutralizing the charged dust by generating an optimal amount of ions having a reverse polarity according to the charge amount of the charged dust blown out from the dust collecting portion.

It is another object of the present invention to provide a dust collector which can detect the polarity and the amount of charge of dust blown out from the charge neutralizing means.

Another object of the present invention is to provide a dust collecting apparatus provided with a method of controlling the charge neutralizing means capable of always keeping the neutralized state of the charged dust blown from the dust collecting section.

[0019]

In order to achieve the above object, the dust collecting apparatus of the present invention has a charging unit for charging dust and a dust collecting unit provided downstream of the charging unit for charging the dust. It is characterized in that it comprises a dust collecting section to be removed, and a charge neutralizing means for releasing ions having a polarity opposite to the charge of the charged dust blown from the dust collecting section is provided on the downstream side of the dust collecting section.

According to the present invention, the dust collector can be used in any type of dust collector and can neutralize the charged dust without relying on the mixing of dust particles having different polarities and with a small discharge current and hardly generating ozone. A dust device is obtained.

According to a second aspect of the present invention, in the dust collector of the first aspect, the charge neutralizing means comprises a discharge electrode and a ground electrode, and a corona is provided between the discharge electrode and the ground electrode. It is characterized in that an insulator or a semi-conductor is provided so as not to generate discharge.

According to the present invention, the corona discharge is surely suppressed in the charge neutralizing means having the reduced distance between the electrodes, the discharge current is small, and the charged dust can be neutralized with almost no generation of ozone. The device is obtained.

The dust collector according to a third aspect of the present invention is the dust collector according to the first or second aspect, in which the charge neutralizing means is a pointed electrode having a sharp tip, and the charge is blown from the dust collector. It is characterized in that it is a means for releasing ions of the same amount as the charge amount of dust and having the opposite polarity.

According to the present invention, it is possible to obtain a dust collecting apparatus capable of generating an optimal amount of ions of opposite polarity in accordance with the charge amount of the charged substance blown out from the dust collecting portion.

The dust collector according to a fourth aspect is the dust collector according to any one of the first to third aspects, further comprising a detection means for confirming the polarity and charge amount of the dust that has passed through the charge neutralization means. It is characterized by having.

According to the present invention, it is possible to obtain a dust collecting apparatus capable of confirming the neutralization of charged dust by detecting the polarity and charge amount of the dust that has passed through the charge neutralizing means.

The dust collector according to a fifth aspect is the dust collector according to the fourth aspect, characterized in that the detecting means is a means for measuring the surface potential of the wall surface or the charging plate.

According to the present invention, it is possible to obtain a dust collecting apparatus which can grasp the charged state of the wall surface and at the same time confirm from the information obtained from the wall surface whether or not the charged dust is actually neutralized.

Further, a dust collector according to a sixth aspect is the dust collector according to any one of the first to fifth aspects, further comprising detection means for confirming the polarity and charge amount of the dust blown from the charge neutralization means. The charge neutralizing means is controlled so that the dust blown from the charge neutralizing means does not always have an electric charge.

Further, according to the present invention, there can be obtained the dust collecting apparatus in which the charge neutralizing means is controlled so that the charged dust blown out from the dust collecting portion can be always kept in a neutralized state.

The dust collector according to claim 7 is the dust collector according to any one of claims 1 to 6, wherein a grounded conductive filter is provided behind the dust collector and before the charge neutralizing means. Characterize.

According to the present invention, large re-scattered particles due to sparks caused by a short circuit can be roughly removed by a conductive filter, and small charged dust that cannot be completely removed can be neutralized by a charge neutralizing means. The device is obtained.

[0033]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention comprises a charging section for charging dust and a dust collecting section provided downstream of the charging section for removing dust, and having a polarity opposite to that of the charged dust discharged from the dust collecting section. It is characterized in that a charge neutralizing means for releasing the ions is provided on the downstream side of the dust collecting portion. The charging part is composed of conductive wires or needles and plates.By giving a high potential difference to both, a high electric field is created around the wires and needles to cause dielectric breakdown of air and ionize the air. An example is one that charges dust. Also, as the dust collecting part, a potential difference is applied between the two electrode plates to create an electric field,
A dust collection unit that mainly collects charged dust by the force of the electric field, a filtration filter that mechanically collects dust by using glass fiber etc. as a filter material, a pre-polarized dielectric material as a filter material, and an electric field inside As an example, an electrostatic filter or the like that is made so that it can be collected and that collects dust by the force of a mechanical or electric field thereof can be given. In the dust collector of the present invention, charged dust that is charged by the charging unit and cannot be collected by these dust collecting units, ions generated by the electric field of the charging unit or the dust collecting unit, or re-scattering from the dust collecting unit It is neutralized by a charge neutralizing means that releases only air ions having a polarity opposite to that of a charged substance such as charged dust.

Conventional wisdom has been that it is effective to use corona discharge as a means for electrically neutralizing charged dust by releasing air ions. In order to generate corona discharge, a ground electrode facing the discharge wire or the needle-shaped electrode is provided, and a high voltage is applied between them. Then, almost no current flows up to a certain voltage. At this time, almost no air ions are generated. However, when the voltage is raised to a voltage at which corona discharge occurs, a high electric field is generated in the vicinity of the discharge electrode, and gas (air) causes local dielectric breakdown to become ions, and at the same time, the current value due to discharge rapidly increases. This is corona discharge. By utilizing the region of corona discharge, which is characterized by a large discharge current, it is possible to ionize air and neutralize charged dust, but there is a problem that the discharge current is large and a lot of ozone is generated. It was

We have only released air ions,
We have found a method to electrically neutralize charged dust without corona discharge. If a voltage is applied to the discharge electrode in the state where a large insulation resistance exists between the linear or needle-shaped discharge electrode and the opposing earth electrode, even if a voltage of 6 to 10 kV is applied, a large discharge due to dielectric breakdown of air occurs. Although current does not occur and corona discharge does not occur (current hardly flows: state of glow discharge), only air ions can be generated by the action of a large electric field near the discharge electrode. The state where no corona discharge is occurring means that, as a specific guideline, if the discharge current is 1 μA or less per one needle electrode (a level that can be measured by a general instrument), and if it is a linear electrode,
The value is 1 μA or less per 0.1 m. Further, in order to create this state, it is necessary to cover the portion that is grounded with an insulating or semiconductor material if air insulation and a sufficient distance cannot be maintained. As the insulation distance in the case of air insulation, in the case of a linear shape, the diameter of the wire, the surface smoothness, and in the case of a needle shape, it cannot be said unequivocally depending on the degree of sharpness, but at least 1 cm / kV or more, preferably, It is necessary to provide an insulation distance of 2 cm / kV or more. As the insulating or semi-conductive material, a material having an insulation resistance with a discharge current of 1 μA or less may be used, although it depends on the insulation distance. By using the discharge that discharges only such air ions as the charge neutralizing means, it is possible to neutralize the charged dust by discharging ions having the opposite polarity to the charged dust blown from the dust collecting portion. Then, there is a Leonard effect as a means for releasing negative ions without using electricity. It is known that many negative ions exist near the waterfall. When water is collided and mechanically divided into fine particles, negative ions are excessive in the small droplets and positive ions are excessive in the large droplets, and the respective ions can be emitted. In particular, if the water molecules are fine particles of 0.5 μm or less, a large amount of negative ions can be released.
Therefore, for example, when the ions blown out from the dust collecting portion are positive, this Leonard effect causes 0.5 μm.
By generating the fine water particles, a large amount of negative ions can be generated, and the positively charged dust blown from the dust collecting portion can be electrically neutralized. Similarly, when negatively charged dust is blown out from the dust collecting portion, it can be neutralized with positive ions generated as water droplets of 0.5 μm or more, preferably 1 μm or more.

As described above, since the charge neutralizing means generates and releases only air ions without causing corona discharge, ozone, which is peculiar to corona discharge and is generated in proportion to the discharge current, is hardly generated. Ozone is harmful to the human body, and if it is ingested in large amounts, various disorders occur. And since a charge neutralizing means for directly neutralizing the electric charge of the charged dust by air ions, which are lighter than the dust and have high electric mobility, is provided on the downstream side of the dust collecting portion, a newly created charged dust of opposite polarity is created. Neutralization is more reliable than mixing, and wall surface contamination due to charged dust can be prevented.Because corona discharge does not have to be neutralized at the dust collecting part to neutralize charged dust, the voltage application electrode plate is exposed. There is no need to eliminate the design freedom of the dust collecting part or to set conditions for the voltage setting of the voltage application electrode plate of the dust collecting part, and it can be applied to any dust collecting device. Since the corona discharge does not occur, the discharge current is small, and the ozone is not emitted excessively.

The charge neutralizing means is composed of a discharge electrode and a ground electrode, and an insulator or a semi-conductor is provided between the discharge electrode and the ground electrode so as not to generate corona discharge. Here, corona discharge is a phenomenon in which when the voltage is raised to a level at which corona discharge occurs, a high electric field is generated near the discharge electrode, causing local dielectric breakdown of gas (air) and causing a rapid increase in current value. Is. When used in the area of corona discharge where the current value is rapidly increasing, air causes dielectric breakdown to generate air ions, but corona discharge has the disadvantages of high discharge current and ozone generation. is there. In order to overcome the drawback, a linear or needle-shaped discharge electrode is used, and an insulator or a semi-conductor is sandwiched between the discharge electrode and the ground electrode so that the discharge current is 1 μA or less as described above. Or cover either electrode. A voltage having a polarity opposite to that of the charged dust is applied to the discharge electrode, and a large electric field is formed near the discharge electrode to ionize the air. If the polarity of the discharge electrode is positive, negative ions created by attaching electrons to air ions are attracted to the discharge electrode and lose the charge, and positive ions created by air molecules losing electrons are Repels and spreads around. Therefore, positive ions are released from the charge neutralization means. If the polarity of the discharge electrode is negative, the opposite occurs and negative ions are emitted. Since the charge neutralizing means is applied with a voltage having a polarity opposite to that of the charged dust, the charged dust passing through the charge neutralizing means is combined with ions of the opposite polarity emitted by the charge neutralizing means and neutralized. By doing so, it is possible to prevent the wall surface from being contaminated due to the adhesion of the charged dust. By installing an insulator or a semi-conductor between the discharge electrode of the charge neutralization means and the ground electrode, the corona discharge is suppressed and the discharge current is reduced, so the charge neutralization means almost eliminates ozone. Generates and releases only air ions without generating them. Since an insulator or a semiconductor is installed between both electrodes to prevent corona discharge and insulation is secured, the gap between both electrodes can be narrowed, and the charge neutralization means should have a compact structure. It has the effect that

Further, the charge neutralizing means is a pointed electrode having a sharp tip so that only ions having the same amount as the charge amount of the charged dust blown out from the dust collecting portion but the opposite polarity are emitted. Therefore, the charge neutralizing means is composed only of the pointed discharge electrodes, and no ground electrode is provided in the surroundings. A voltage having the opposite polarity to the charged dust is applied to the pointed discharge electrode, but if the charged dust does not leak from the dust collecting portion, it does not emit air ions. However, when the charged dust leaks out, the atmosphere near the pointed discharge electrode is filled with the charge of the charged dust, and a large potential difference is generated between the pointed discharge electrode and its surroundings, and a large electric field is formed near the pointed discharge electrode. The air is ionized and emits air ions having the opposite polarity to the charged dust to neutralize the charged dust.
At that time, the pointed discharge electrode is set to an optimum voltage that emits air ions of opposite polarity and the same amount as the leaked charged dust. Further, since the discharge current is very small, ozone which is harmful to the human body is hardly generated. At this time, if a corona discharge is caused, the insulation of the air is destroyed and the ions are emitted, so a certain amount of ions are emitted regardless of the amount of surrounding ions. However, the means for releasing only ions without corona discharge according to the present invention releases the amount of ions due to the electric field difference between the surrounding amount of ions (the amount of charge) and the discharge electrode. In the case of releasing, it also has a self-made product that releases many negative ions when there are many surrounding positive ions and emits few negative ions when there are few surrounding positive ions. Then, since the charge neutralizing means emits air ions of the same polarity and the same amount as the leaking charged dust to neutralize the charged dust, the fine voltage control of the discharge electrode is not performed, and the surface dust caused by the charged dust is eliminated. In addition, it has an effect of preventing excessive pollution of air ions by discharging excess air ions and charging the wall surface of the dust collector blowing air, and hardly emitting ozone.

Further, it is characterized in that it has a detection means for confirming the polarity and charge amount of the dust that has passed through the charge neutralization means,
Whether to measure the surface potential of the wall surface on the downstream side of the charge neutralizing means, or to install a conductor that is not electrically connected to anywhere on the downstream side of the charge neutralizing means and measure the surface potential, In addition, by using a powder suction type Faraday gauge, etc., to detect the amount of charges in the air on the downstream side of the charge neutralization means, etc. Set up. If the measurement result of the charged state of the dust by the detection means shows electrical neutrality and the dust or wall surface is not charged, if the measurement result is biased to plus or minus, neutralize the charged dust. It can be said that the wall surface is easily soiled because it is not cut off, or the amount of air ions released by the charge neutralization means is too large and the dust or the wall surface is charged with the opposite polarity. By knowing the wall surface on the downstream side of the charge neutralizing means and the charged state of the air, it is possible to obtain the optimum setting of the charge neutralizing means in order to neutralize the electrostatic charge of dust and prevent wall surface contamination. Have.

Further, the charge neutralizing means has a detecting means for confirming the polarity and the charge amount of the dust discharged from the charge neutralizing means, so that the dust discharged from the charge neutralizing means always has no charge. It has the feature of finely controlling ion emission. If the wall surface on the downstream side of the charge neutralization means is charged, it means that the charged dust particles have not been completely neutralized, or the amount of air ions released by the charge neutralization means is too large, and the dust particles and wall surfaces are reversed in polarity. It can be said that it is in a charged state. Therefore, in order to always keep the charged dust in a neutralized state, it suffices that the measurement result of the charged state of the dust by the detection means always shows non-polarity. The charged state of the dust passing through the charge neutralizing means is measured by the detecting means, and if it is found that the dust is charged, the voltage controlling means for controlling the voltage of the discharge electrode of the charge neutralizing means is the most suitable ion. By changing the voltage so that the discharge amount is obtained, and feeding back the result of the detection means until the detection means no longer displays the charge, and continuing the control, the dust is always kept uncharged and the wall surface is always cleaned. It has the effect that it can be automatically managed to prevent it.

Further, it is characterized in that a grounded conductive filter is provided behind the dust collecting portion and before the charge neutralizing means. In electric dust collectors used for road tunnels, the target of removal is mainly carbon-based particles such as hydrocarbons contained in exhaust gas from automobiles, but carbon-based particles have a low electrical resistance and therefore dust collection. When a large amount is deposited on the electrode plates of some parts, electricity is locally applied, which causes a short circuit between the electrode plates. Sparks that occur at that time impact the electrode plate, and the impact causes the treated dust accumulated on the electrode plate to separate from the electrode plate, and a large amount of re-scattered particles are generated from the dust collecting portion. At this time, there is a possibility that an amount of charged dust that exceeds the charge neutralizing ability of the charge neutralizing means will be scattered from the dust collecting portion. Therefore, a conductive filter such as a wire mesh or steel wool with a fine mesh is installed behind the dust collector and in front of the charge neutralization means to remove large re-scattered particles and to charge the small re-scattered particles that could not be removed. There is an effect that it is possible to more effectively prevent the wall surface from being soiled by returning to the non-charged state by the summing means.

[0042]

EXAMPLES Examples of the present invention will be described below.

(Embodiment 1) FIG. 1 shows a dust collector equipped with a charge neutralizing means using ions formed by fine water droplets. As shown in FIG. 1, the charging unit 101 includes a discharge electrode A102 formed of a discharge line and a ground electrode plate A103, and a dust collecting unit including a voltage application electrode plate 105 and a ground electrode plate B106 on the downstream side of the charging unit 101. 104 is provided. Normally, in the charging unit 101, the discharge electrode A102
5 to 15 kV, and a DC voltage of 2 to 6 kV is applied to the voltage application electrode plate 105 of the dust collecting unit 104.
07 is applied. The charge neutralizing means 1 is provided on the downstream side of the dust collecting unit 104. The charge neutralizing means 1 is
A tank 2 for storing water, a nozzle 3 for ejecting water at high speed, and a pump 4 for delivering the water stored in the tank 2 to the nozzle 3 are provided.

In the above structure, when positive DC high voltage is applied to the charging section and the dust collecting section, dust having positive ions is emitted from the dust collecting section. In the static eliminator installed downstream of the dust collector, the nozzle diameter is made as small as possible, and at the same time, it is blown out at a high speed to spray fine water droplets of 0.5 μm or less to release a large amount of negative ions. . Moreover, although only three nozzles are shown in the figure, it is preferable to discharge negative ions with a plurality of nozzles so as to discharge them as uniformly as possible with respect to the area of the dust collecting portion. In this way, the negative ions emitted from the charge eliminating unit are attracted to each other by the Coulomb force and the dust having the positive ions emitted from the dust collecting unit, and finally, they are attached and electrically neutralized. Since the neutralized dust has no electric charge, it is possible to prevent the dust from adhering to the wall surface.

Further, when a negative DC high voltage is applied to the charging section and the dust collecting section, dust having negative ions is discharged from the dust collecting section. By setting the particle size to 0.5 μm or more, positive ions are released and electrically neutralized to prevent adhesion to walls and the like. However, if the particle size of water is close to 0.5 μm, the amount of positive ions is small, so 1 μm or more is preferable, and if it is too large, water droplets will drop downwards, which is related to wind speed, but 5 μm or less is desirable. .

As a means for atomizing water, in this embodiment, fine particles of water were generated using a nozzle. However, a method of impinging water on a substance at high speed to atomize the water or other ultrasonic waves is used. Any method can be used as long as it can be controlled to the above-mentioned specific particle size, such as miniaturization. However, even if it is simply humidified, ions are not generated unless it is miniaturized, and therefore it is distinguished from the usual humidification method.

As a means for releasing only ions without causing corona discharge, a method of utilizing radiation other than the method of atomizing water (a method of irradiating alpha rays (particles) to ionize air molecules) ) Method of using soft X-rays (method of ionizing air molecules with soft X-rays, which is a type of electromagnetic wave having a very short wavelength), method of using ultraviolet rays (method of ionizing air molecules by emitting ultraviolet rays) And the like, and any method can neutralize the charged dust.

(Embodiment 2) FIG. 2 shows a dust collecting apparatus provided with a charge neutralizing means for releasing only ions having a polarity opposite to that of charged dust on the downstream side of the dust collecting portion. The charging unit 101 is composed of a linear discharge electrode A102 and a ground electrode plate A103, and charges the taken-in dust in the air to the polarity of the discharge electrode A102. The charged dust is introduced into the dust collecting portion 104 composed of the voltage application electrode plate 105 and the ground electrode plate B106, and receives the electric field force between the two electrode plates to adhere to one of the electrode plates to be removed. Then, the dust collecting portion 10 cannot be completely removed.
The charged dust leaking from 4 is introduced into the charge neutralizing means 1,
The charge is neutralized by being combined with ions of opposite polarity emitted by the charge neutralization means 1, and is blown out from the blower fan 108 in an uncharged state. The charge neutralizing means 1 includes a discharge electrode B5 to which a voltage having a polarity opposite to that of charged dust is applied, and a ground electrode plate C6 sandwiching the discharge electrode B5.
It emits ions of the opposite polarity to charged dust. Here, the surface of the ground electrode plate C6 is covered with an insulating or semi-conductive film layer 7 to suppress the discharge current and prevent the discharge current from occurring. Therefore, in the vicinity of the discharge electrode B5 of the charge neutralizing means 1, only ions having a polarity opposite to that of the charged dust are generated and released, and the generation of other components such as ozone is suppressed. Since the ozone generation amount is proportional to the discharge current, suppressing the discharge current leads to suppressing ozone generation.

(Embodiment 3) FIG. 3 shows a dust collecting apparatus provided with a charge neutralizing means 1 composed of only a pointed discharge electrode 8. The dust is charged by the charging unit 101 and is similar to the dust collector of FIG. 1 until it is introduced into the dust collecting unit 104 and removed. However, the charged dust leaked from the dust collecting unit 104 without being completely removed is charged. It is introduced into the neutralizing means 1, is combined with ions of opposite polarity emitted by the charge neutralizing means 1 to be neutralized, and is blown out from the blower fan 108 in an uncharged state. At this time, the charge neutralizing means 1 is composed of only the pointed discharge electrodes 8 and a voltage having a polarity opposite to that of the charged dust is applied. In the state where there is no electric charge in the surroundings, the pointed discharge electrode 8 does not emit ions, but when the charged dust leaks from the dust collecting section 104 and becomes present in the surroundings, the pointed electrode having a polarity opposite to that of the charged dust. The potential difference between the discharge electrode 8 and the surrounding where charged dust is present becomes large, and as a result, a large electric field is present. Then, due to the action of the electric field, air is ionized in the vicinity of the electrodes, and ions having the opposite charge polarity and the same charge amount as the charged dust are generated and released.
At this time, the discharge current flowing from the pointed discharge electrode 8 is minute and ozone is hardly generated. Further, in the state where there is no charged dust, the pointed discharge electrode does not emit ions, so that the extra wall is normally discharged, and the wall surface is not contaminated by being charged.

(Embodiment 4) FIG. 4 shows a dust collector in which a detecting means 9 for measuring the polarity and charge amount of dust passing through the charge neutralizing means 1 is provided on the downstream side of the charge neutralizing means 1. . The charged state of the dust after passing through the charge neutralizing means 1 is reflected on the wall surface on the downstream side and the air itself. Then, the surface potential of the wall surface on the downstream side of the charge neutralizing means is measured by the surface electrometer 10. Alternatively, an electrically conductive plate 11 electrically suspended in the air is installed on the downstream side of the charge neutralizing means 1, and the surface potential thereof is measured by the surface electrometer 1
By measuring at 0, it is possible to know whether the dust passing through the charge neutralizing means 1 is charged. Further, the charge-type neutralization means 1 is equipped with a suction type Faraday gauge 12 capable of sucking air and measuring the total of charges such as dust contained therein.
Installed on the downstream side of, the charge of the dust passing through the charge neutralizing means 1 can be directly measured. By providing the detecting means 9 such as these, the charged dust is prevented from becoming the charge neutralizing means 1.
After passing through, whether the dust charge has disappeared,
Further, it is possible to know whether the charge neutralizing means 1 outputs excessive ions larger than the amount for neutralizing the charged dust to charge the dust to the opposite polarity or to charge the wall surface.
It can be used as a standard for adjusting the ion emission of the charge neutralizing means 1.

The detection means differs depending on what kind of place or site is to be electrically neutralized, but when the adhesion to the wall surface is important, the surface potential of the wall surface is detected. To do. As a means for measuring the surface potential,
There is a surface electrometer that measures the wall surface potential by reflecting it on the probe, and it can be easily measured. Further, when it is important to consider whether the charge is neutralized at the outlet by the charge neutralizing means, a positive or negative high voltage is applied to the charging plate having a known electrostatic capacity to charge the charging plate. The ion balance can be evaluated by measuring the potential when the ions adhere to the, and the neutralization state can be easily measured.

(Embodiment 5) FIG. 5 has a detection means 9 for measuring the polarity and charge amount of the dust that has passed through the charge neutralization means 1.
1 shows a dust collector capable of controlling the charge neutralizing means 1 so that the dust that has passed through the charge neutralizing means 1 does not always have an electric charge. The charged state of the dust passing through the charge neutralizing means 1 is measured by the detecting means 9, and if it is found that the dust is charged, a voltage control means for controlling the voltage of the discharge electrode B5 of the charge neutralizing means 1. The voltage is changed so that the amount 10 of ions is optimally supplied, and the voltage control unit 13 feeds back the voltage until the detection unit 9 no longer displays the charge, and the control is continued, so that the dust is not always charged. You can continue.

Next, it was verified whether the charge neutralizing means described in Embodiments 1 to 5 actually exhibited the effect. Experimental schematic diagrams are shown in FIGS. 6 and 7. Aperture size 13
In a duct of 2 mm × 122 mm, a charging unit 101, a charge neutralizing unit 1, and a charged dust removing device 1 in order from the air blowing direction.
4. A blower fan 108 is installed. The wind velocity in the duct was 0.5 m / s. Charging unit 101 that creates charged dust
Is a tungsten wire discharge electrode A102 having a wire diameter of 0.15 mm and a length of 110 mm, which is simplified in the figure.
Six of them are installed at an interval of mm, and the depth dimension 1 in the longitudinal direction of the blast flow is so as to sandwich the discharge electrodes A102 arranged side by side.
A steel ground electrode plate A103 having a width of 6 mm and a width of 110 mm is installed. A DC voltage of +5.7 kV is applied to the discharge electrode A102, and the discharge current at this time is 70 μA.
Met. In order to make the neutralizing effect clearly visible, the charge neutralizing means 1 is installed without the dust collecting unit 104 behind the charging unit 101, and the charged dust produced by the charging unit 101 remains unchanged. The charge was neutralized by the means 1. The distance between the charging section 101 and the charge neutralizing means 1 is 50 mm
Is. And to evaluate the neutralizing effect of charged dust,
The charged dust removing device 14 was installed 400 mm behind the charge neutralizing means 1. The charged dust removing device 14 is structurally the same as the dust collecting unit 104. Although it is shown briefly in the figure,
Specifically, thickness 0.5mm, depth length 50mm, width 1
Twenty-three stainless steel plates of 28 mm are stacked at 5 mm intervals and a voltage is applied every other plate to form 12 voltage application electrode plates, and 11 plates sandwiched between them are connected to the ground to form a ground electrode plate. did. A DC voltage of +2 kV is applied to the voltage application electrode plate. If the dust is charged, it is subjected to a Coulomb force by the electric field formed between the two electrode plates and adheres to one of the electrode plates to be removed. If the charged dust is neutralized by the charge neutralization means 1, the dust is not removed and passes through the charged dust removing device 14 to come out. Therefore, the neutralization performance of the charge neutralization means 1 can be evaluated by measuring the dust removal rate η before and after the charged dust removing device 14 and obtaining the dust passage rate 1-η. Assuming that the dust concentration immediately before the charged dust removing device 14 is Cin and the dust concentration immediately after is Cout, the dust passage rate is 1−η = 1− (Cin−Cout) / Cin = Cout.
It can be calculated by the formula / Cin. Further, the air ion concentration and the amount of ozone generated from the charge neutralizing means were also measured to evaluate the performance as the charge neutralizing means. The dust concentration is a particle counter KC-01C made by Rion that measures the number concentration of dust with a particle size of 0.3 μm or more, and the air ion concentration is the number concentration of small ions with an electric mobility of 0.4 cm ² / V · cc or more. An ion counter KST-900 manufactured by Kobe Denpa Co., Ltd., and an amount of generated ozone were measured using an ozone monitor EG-2001F manufactured by EBARA CORPORATION. Then, the following two charge neutralizing means were prepared as Examples A and B, and the results of evaluating the neutralizing performance of the respective charged dusts are shown in Tables 1 and 2.

FIG. 6 is a schematic diagram of the experiment of Example A. The charge neutralizing means 1 has the same structure as that of the charging portion 101, but the ground electrode plate C6 is entirely covered with an insulating film layer 7 made of vinyl chloride. A direct current voltage was applied to the discharge electrode B5 of the tungsten wire in the range of 0 kV to -6 kV, and the dust passage rate, the air ion concentration, and the amount of ozone generated from the charge neutralizing means 1 were measured when each voltage was applied. The results are shown in Table 1.

[0055]

[Table 1]

Looking at the dust passage rate, the voltage with the highest neutralizing effect is around -4 kV, and the dust passage rate at that time is 70 kV.
%Met. The passing rate at 0 kV is 4%, and the charged dust that was 96% as a whole was 100-70 = 30%.
Therefore, from the calculation of (96-30) /96=0.69, it can be said that about 69% of all charged dust could be neutralized. Looking at the positive and negative balance of air ions, it seems that it is neutralized at -2 kV,
A voltage of about -4 kV was required to neutralize the charged dust. This optimum neutralization voltage is applied when a voltage of +5.7 kV is applied to the discharge electrode A102 of the charging unit 101 and a discharge current of 70 μA is applied. If the voltage or size of the charging unit 101 changes, the optimum neutralization voltage is optimum. It is necessary to search the neutralization voltage in this way. Although not shown in Table 1, the ozone concentration generated from the charging unit 101 is 38 ppb.
Therefore, it was found that the ozone concentration generated from the charge neutralization means 1 was as low as 1 ppb at -4 kV, and the charge neutralization means 1 hardly generated ozone near the optimum neutralization voltage.

FIG. 7 is a schematic diagram of the experiment of Example B. The charge neutralizing means 1 of Example B has a body diameter of 0.7 m.
It has a structure in which three pointed discharge electrodes 8 made of a steel needle having a sharp tip at m are installed, and no ground electrode is provided in the periphery. A voltage was applied to the pointed discharge electrode 8 in the range of 0 kV to -6 kV, and the dust passage rate and the air ion concentration when each voltage was applied, and the ozone concentration when the voltage was applied only to the charge neutralizing means were measured. did. The results are shown in Table 2.
Shown in.

[0058]

[Table 2]

The voltage with the highest neutralizing effect was -3 kV, and the dust passage rate at that time was 74%. The passing rate at 0 kV was 4%, and the charged dust, which was 96% of the whole, was 100-74 = 26%, so from the calculation of (96-26) /96=0.73, This means that about 73% of the charged dust could be neutralized. A major feature of the charge neutralizing means 1 of Example B is that air ions are hardly released when no charged dust is present, but ions of opposite polarity are released according to the amount of charged dust present. . When no voltage is applied to the discharge electrode A102 of the charging unit 101 and no charged dust is present, the amount of ions emitted from the charge neutralizing means 1 is 0 even if -3 kV is applied, but the discharge electrode of the charging unit 101 is A10
When a voltage is applied to No. 2 and charged dust is present, negative ions are emitted at a concentration of 240,000 / cc. The negative ions neutralize the positively charged dust. Therefore, normally, the dust is not charged to the opposite polarity, or the wall is not charged by emitting ions, but when the charged dust is introduced into the charge neutralization means 1, it is said that the ions of the opposite polarity are released. It has very convenient features. This optimum neutralization voltage is + 5.V to the discharge electrode A102 of the charging section 101.
This is a case where a voltage of 7 kV is applied and a discharge current of 70 μA is applied, and if the conditions of the charging section 101 change, it is necessary to find the optimum neutralization voltage by such a method. Further, almost no ozone was generated from the charge neutralizing means 1 using the pointed discharge electrode.

(Embodiment 6) FIG. 8 shows a case in which ten conductive filters 15 made of stainless steel having a 5 mm square mesh are stacked and arranged in front of the dust collecting portion and in front of the charge neutralizing means. This filter is all grounded. The carbon-based particles contained in the exhaust gas of automobiles have a low electric resistance.Therefore, electric-type dust collectors used for road tunnels often suffer from sparks due to short circuits due to carbon-based particles accumulated in the dust-collecting part. Happens in. At that time, the dust accumulated on the electrode plate due to the impact of the spark jumps to the facing electrode plate and then to the facing electrode plate. And finally it goes out from the dust collecting part. This is the re-scattering phenomenon. The re-scattered particles are often charged with either polarity due to the jumping phenomenon. When re-scattering,
The dust adhering to the electrode plate suddenly emerges from the dust collection part and becomes re-scattered particles, so if it were all charged, it would exceed the neutralization capacity of the charge neutralization means and became charged. There is a possibility that it will be discharged from the dust collector as it is. Considering pressure loss, therefore, a grounded open conductive filter 15 is provided behind the dust collecting part and before the charge neutralizing means to remove a large amount of re-scattered particles at once or to absorb the charge. In this way, the small charged dust that cannot be completely removed is neutralized by the charge neutralizing means located at the rear. In this way, by using a two-stage charge neutralization method in which a conductive filter is provided and a charge neutralization means is provided behind it, in a dust collector used in a place where a large amount of dust is handled. Also, it is possible to prevent the charged dust from being discharged and prevent the wall surface from being soiled.

Incidentally, the dust collecting portion is one which gives an electric potential difference between the voltage applying electrode plate and the earth electrode plate to create an electric field and mainly collects the charged dust by the force of the electric field.
A filter that uses glass fibers as a filter material to mechanically collect dust, or a dielectric material that has been polarized in advance is used as a filter material to create an electric field inside and to collect dust mechanically or by the force of the electric field. Similar effects can be obtained when other types of dust collecting parts such as an electrostatic filter for collecting are used.

In the embodiment, the linear discharge electrode in the charging section is made of tungsten, but the same effect can be obtained when other conductive metal or resin is used as the discharge electrode.

In the embodiment, a sharp steel needle having a sharp tip was used as the pointed discharge electrode. However, if air can be ionized, the same effect can be obtained with other conductive metals or resins. Occurs.

In the embodiment, a DC voltage is applied to the discharge electrode of the charge neutralizing means, but an AC voltage may be applied as long as ions of the opposite polarity to the charged dust are emitted.

Although the method of measuring the surface potential of the wall surface or the amount of charge of air has been taken as an example of the detecting means for detecting the charge of the dust passing through the charge neutralizing means, any measuring method can be used if it is a means of detecting the charge. There is no difference in the effect of other things.

Further, although a metal mesh of 5 mm square mesh made of stainless steel was used as the conductive filter, the same effect can be obtained by using another material as long as it is conductive and breathable.

[0067]

As is apparent from the above description, according to the present invention, wall surface cleaning is performed by preventing stains on the wall surface and suppressing pollution around the wall surface while generating almost no harmful ozone to the human body, and cleaning the wall surface. It is possible to provide a dust collector having an effect of reducing maintenance costs such as.

Further, it is compact in size, produces almost no harmful ozone to the human body, prevents stains on the wall surface, suppresses contamination of the surroundings, maintains aesthetics, and reduces maintenance costs such as wall surface cleaning. It is possible to provide a dust collector having

In addition, it is possible to easily and optimally prevent stains on the wall surface by using only a small amount of discharge energy and generate little ozone, thereby suppressing contamination of the surroundings and reducing maintenance costs such as wall cleaning at a small cost. A dust collector having an effect can be provided.

Further, by providing the detecting means for grasping the charged state of the dust which has passed through the charge neutralizing means, it is possible to provide the dust collecting apparatus which can obtain the optimum setting for always preventing the wall surface contamination. .

Further, detection means for grasping the charged state of the dust passing through the charge neutralizing means is provided, and the charge neutralizing means is controlled so that the result is always neutral, whereby wall surface contamination is always prevented. As described above, it is possible to provide a dust collector that automatically manages and reduces maintenance costs and management costs.

In addition, even under severe operating conditions such as a large amount of dust and dust removed in the dust collecting portion re-scattering and discharging a large amount of re-scattered particles, the conductive filter is placed in front of the charge neutralizing means. To remove large dust, or to neutralize the charge of dust to some extent by contact, and to neutralize the charged dust almost completely by the charge neutralization means behind it to prevent wall surface contamination. It is possible to provide a dust collector that is aesthetically pleasing and that can reduce maintenance costs around the dust collector.

[Brief description of drawings]

FIG. 1 is a block diagram of a dust collector equipped with charge neutralizing means using ions formed by fine water droplets.

FIG. 2 is a block diagram of a dust collector provided with a charge neutralizing means in which corona discharge is suppressed by a coating layer.

FIG. 3 is a block diagram of a dust collector including a charge neutralizing device composed of pointed discharge electrodes.

FIG. 4 is a configuration diagram of a dust collecting device provided with a detection unit below the dust collecting unit.

FIG. 5 is a configuration diagram of a dust collector including a voltage control unit for a detection unit and a charge neutralization unit.

FIG. 6 is an experimental schematic diagram of the charge neutralizing means of Example A.

FIG. 7 is an experimental schematic diagram of the charge neutralizing means of Example B.

FIG. 8 is a block diagram of a dust collector in which a conductive filter is provided behind the dust collector and before the charge neutralizing means.

FIG. 9 is a block diagram of a conventional electric dust collector

[Explanation of symbols]

1 Charge neutralization means 2 tanks 3 nozzles 4 pumps 5 Discharge electrode B 6 Earth electrode plate C 7 Insulating or semi-conductive film layer 8 Pointed discharge electrode 9 Detection means 10 Surface electrometer 11 Conductive plate 12 Suction-type Faraday gauge 13 Voltage control means 14 Charged dust remover 15 Conductive filter

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI F24F 7/06 H05F 3/04 J // H05F 3/04 B03C 3/14 B (56) Reference JP 2001-170516 (JP , A) JP-A-6-247139 (JP, A) JP-A-2000-24544 (JP, A) JP-A-53-64878 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) ) B03C 3/00-3/88

Claims (8)

(57) [Claims] And 1. A charge section for charging dust, charges that disposed downstream includes a dust collecting unit for removing dust, releasing a charge polarity opposite to the ion charge dust blown from the dust collection unit A dust collecting device in which a needle electrode is provided on the downstream side of the dust collecting portion as a neutralizing means. 2. The charge neutralizing means comprises a discharge electrode and a ground electrode, and an insulator or a semiconductor is provided between the discharge electrode and the ground electrode to prevent corona discharge. Dust collector. 3. The charge-neutralizing means is one or a plurality of needle-shaped electrodes having sharply pointed tips, and discharges only ions having the same amount as the charge amount of the charged dust blown from the dust collecting portion but the opposite polarity. The dust collecting apparatus according to claim 1 or 2, which is used as a means. 4. A charging section for charging dust and its downstream side
It is equipped with a dust collector that removes dust from the
Releases ions of the opposite polarity to the charge of the charged dust
As a charge neutralizing means, a fine water droplet spraying means is provided on the downstream side of the dust collecting section.
Dust collector provided . 5. The dust collecting apparatus according to any one of claims 1 to 4 having a detecting means for checking the polarity and charge amount of dust passing through the charge neutralizing means. 6. The dust collecting apparatus according to claim 5, wherein the detecting means is means for measuring a surface potential of a wall surface or a charging plate. 7. A charge neutralizing means is always controlled so as to have a detecting means for confirming the polarity and charge amount of the dust which has passed through the charge neutralizing means, so that the dust blown out from the charge neutralizing means has no charge. The dust collector according to any one of claims 1 to 6 , further comprising: 8. A dust collecting apparatus according to any one of claims 1 to 7 provided with a rear, electrically conductive filter which is grounded to the charge neutralization means before the dust collection unit.