JP3512251B2 - Electric dust collector - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic precipitator which utilizes a corona discharge to give an electric charge to dust in a dust-containing gas and collects the charged dust by an electric force.

[0002]

2. Description of the Related Art Heretofore, this type of electrostatic precipitator has been widely used as an environment-improving device in a factory or the like to remove dust in dust-containing gas, and gives an electric charge to the dust in dust-containing gas. A charging unit and a dust collecting unit that collects the charged dust, that is, charged dust by an electric force due to Coulomb force,
It is composed of a high-voltage power supply unit that supplies a high voltage to the charging unit and the dust collecting unit.

An ionizing wire for corona discharge and a ground electrode are provided in the charging section, and a high voltage electrode plate and a ground electrode plate for collecting charged dust are provided in the dust collecting section. A parallel plate type made of an aluminum material is widely used as the high-voltage electrode plate and the ground electrode plate of the dust collecting part, and the high-voltage power supply part is controlled to output a high voltage.

The dust-containing gas flowing into the charging section and the dust collecting section is
In addition to normal dust, it may contain water or conductive dust. In addition, dust-containing gas in the welding environment often contains flammable substances such as slag scattered from the work, spatter of metal particles, or cutting oil evaporated from the work, rust preventive oil, cleaning oil, etc. . Moisture and conductive dust cause sparks, and flammable substances cause ignition. Therefore, it is necessary to keep the electrostatic capacity low in the dust collecting portion to prevent sparks and ignition. Therefore, in the dust collecting portion, the high voltage electrode plate or the ground electrode plate is divided, or the high voltage electrode plate has an electric resistance interposed therebetween.

For example, as shown in the schematic diagram of FIG. 12, the high-voltage electrode plate 1 and the ground electrode plate 2 are divided into two parts, and the voltage drop due to the spark is suppressed only between the electrodes of the spark generating part. ing. Further, the high-voltage electrode plate 1 is connected to the high-voltage power supply unit 4 via the high electric resistance 3, the current due to the spark is limited, and the voltage applied to the high-voltage electrode plate 1 is prevented from decreasing. As shown in FIG. 13, the high-voltage power supply unit 4 has a load characteristic of a supply voltage of 6.5 KV and a supply current of 300 μA or less, for example.

[0006]

However, the above-mentioned conventional example has the following problems in the dust collecting portion.

(A) Since the supply voltage cannot be lowered in terms of electric field strength and dust collection efficiency, the generation of sparks cannot be suppressed.

(B) Since voltage and current may be used within the ignition region R shown in FIG. 13, when a combustible substance adheres to the electrode plate, dust may ignite and smoke. In particular,
When flammable substances are mixed in the dust-containing gas, the accumulated dust is easily ignited by sparks or spatters. In this case, the dust collector must be stopped to take measures.

(C) When moisture, conductive dust, or combustible dust adheres to the insulating portion, poor insulation occurs and the dust collection efficiency decreases.

(D) Since it is necessary to divide the high-voltage electrode plate 1 and the ground electrode 2 and to provide the high electric resistance 3, the space and the number of parts are increased, and the apparatus becomes large and the cost becomes high.

An object of the present invention is to solve the above-mentioned problems and prevent sparks, insulation failure and ignition even if the dust-containing gas contains water, conductive dust and combustible substance and collects dust. An object of the present invention is to provide an electrostatic precipitator that maintains good efficiency.

[0012]

An electric precipitator in accordance with the present invention for achieving the above object In order to achieve the above, a charged section that gives a charge to dust in the dust-containing gas, a high voltage electrode plate on the downstream of the charged portion In an electrostatic precipitator having a ground electrode plate and a ground electrode plate alternately arranged in parallel at a predetermined interval and collecting the charged dust by an electric Coulomb force, the high-voltage electrode plate is It consists of a semi-insulating resin material , and the
The ground electrode plate is supported by a power supply shaft and is arranged.
The power feeding shaft is made of a conductive material and is surrounded by the power feeding shaft.
It is arranged so that it does not come into contact with the
The high-voltage power supplied to the high-voltage electrode plate is limited to such a level that the dust adhering to the electrode plate will not ignite.

[0013]

[0014]

In the electrostatic precipitator of the present invention having the above-mentioned structure, the high voltage electrode plate is molded from the semi-insulating resin material and the power supply shield is formed.
Placed around the shaft and the ground electrode plate in the same way as the power supply shaft.
Since it is placed around, it is possible to achieve efficient placement and is compact.
Is realized, and the resistance of the semi-insulating resin material restricts the movement of electric charges of the high voltage electrode plate to prevent the occurrence of sparks .

[0015]

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail with reference to the embodiments shown in FIGS. FIG. 1 is a perspective view of this embodiment,
The main chamber 11 accommodates a charging part, a dust collecting part, etc., and a control part 12 for controlling the charging part, the dust collecting part, etc. is connected to the rear part of the main chamber 11, and the main chamber 11
A front chamber 13 for accommodating the collision plate is connected to the front part of the.

In the main chamber 11, as shown in FIG. 2, the front chamber 13 side of the chamber body 21 serves as an inflow port 21a through which dust-containing gas flows in the direction A, and one side surface is provided with the mounting port 2
1b, and an outlet 21c through which clean gas flows in the direction B is provided on the upper surface. Such a chamber body 2
A filter 22, a charging unit 23, two dust collecting units 24, a filter 25, and a suction fan (not shown) are installed in the unit 1 in this order from the inlet 21a side via a mounting port 21b. Here, the charging unit 23 has an ionization line and a ground electrode to charge the dust of the dust-containing gas that has flowed in, and the dust collection unit 24 has a high-voltage electrode plate and a ground electrode plate, which will be described later, and is charged. The dust is collected by electric force due to Coulomb force.

A door 26 is attached to the mounting port 21b so as to be openable and closable, and a high-voltage supply insulator 27 for supplying a high voltage from a high-voltage power source to the charging unit 23 is provided inside the door 26.
And a high voltage supply insulator 28 for supplying a high voltage to the dust collection unit 24. A filter 29 is provided at the outlet 21c. Then, the control unit 12
Controls start and stop, controls a high-voltage power supply unit, and further detects and judges an abnormal state and outputs a control signal.

In the dust collecting unit 24, as shown in a partially enlarged perspective view of FIG. 3 and a partially enlarged sectional view of FIG.
A guide groove 31a is provided in the upper part of the plate 1, and a large number of flat plate-shaped ground electrode plates 32 and high voltage electrode plates 33 are alternately arranged inside and arranged in parallel at a predetermined interval. The ground electrode plate 32 is formed of a metal material having high conductivity such as iron, aluminum, and stainless steel. For example, when a positive charge is applied to the dust-containing gas in the charging unit 23, the ground electrode plate 32 is provided on the negative electrode side of the high-voltage power supply unit. It is grounded.

Here, when the electric resistance of the ground electrode plate 32 is high, the electric charge of the charged dust is accumulated in the ground electrode plate 32 and the electric field strength of the ground electrode plate 32 and the high voltage electrode plate 33 is lowered, The dust collection effect will be significantly reduced. For this reason, the electric field strength is reinforced by coating the surface of the ground electrode plate 32 with a conductive paint having high conductivity or molding the ground electrode plate 32 with a synthetic resin material having high conductivity. Good.

On the other hand, the high-voltage electrode plate 33 is made of a semi-insulating resin material, and has a flat plate-shaped collecting portion 33a for collecting charged dust with the ground electrode plate 32, and a space between the high-voltage electrode plates 33. In order to hold the power supply in a predetermined manner, a spacer portion 33b integrally formed and protruding on both sides is provided, and an insertion hole 33c for inserting a power supply shaft described later is provided. Since the resistance of the semi-insulating resin material changes depending on the water absorption rate, in this example, in consideration of the characteristics of the dust collection efficiency obtained from the experimental results as shown in FIG. For example, a phenol resin, an epoxy resin, an ABS resin or the like having a rate of about 10 ¹⁰ to 10 ¹³ Ω · cm is used.

As the semi-insulating resin material, Sumilite PL (JIS-PEV) is used for phenol resin and Sumilite EL (JIA-GEM, JIS-GE) is used for epoxy resin.
F), and Max resin JSR-HN9 for ABS resin
01 etc. can be used. Further, although the power feeding shaft 35 and the pipe-shaped cover 34 are molded as separate members, if these are integrally molded by insert molding, no gap is created between the power feeding shaft 35 and the pipe-shaped cover 34. The voltage can be supplied more evenly.

Insertion hole 33c of such high voltage electrode plate 33
A pipe-shaped cover 34 made of a semi-insulating resin material equivalent to the high-voltage electrode plate 33 is fitted on the pipe-shaped cover 3.
A predetermined number of high-voltage electrode plates 33 are assembled by inserting the power feeding shaft 35 into the inside of 4. In this case, since the spacer portions 33b are provided on both sides of the high-voltage electrode plate 33, by bringing the spacer portions 33b into close contact with each other, the power feeding shaft 35 has no bare portion, and
The high voltage electrode plates 33 are arranged at equal intervals.

A seal boss 36 having a flange 36a is fitted to the pipe-shaped cover 34 on the outer side of the outermost high-voltage electrode plate 33, and the fitting portion is sealed by an O-ring 37. On the extension line of the power supply shaft 35,
A high voltage supply insulator 28 for supplying a high voltage to the power supply shaft 35 is fixed to the door 26. The door 26 is in contact with the partition wall 40 on the power feeding shaft 35 side through a packing 39.

Further, the partition wall 40 has a stepped hole 41a at the center,
An insulator 41 having 41b and a plurality of fins 41c on the outer periphery is attached, a seal boss 36 is fitted in the stepped hole 41a, and the fitting portion is sealed by two O-rings 42, 43. The power supply shaft 35 is an insulator 41.
It is fixed by a conductive screw 45 via an insulating plate 44, and the conductive screw 45 and the high-voltage supply insulator 28 are electrically connected by a conductive spring 46.

In the power supply circuit to the dust collecting unit 24 thus constructed, the high voltage electrode plates 33 are inserted between the ground electrode plates 32 arranged side by side as shown in FIG. The electrode plate 32 is grounded, and the high voltage electrode plate 33 is connected to the high voltage power supply unit 47. Here, in the high-voltage power supply unit 47, the high-voltage electrode plate 33 is molded from a semi-insulating resin material,
Since almost no sparks are generated, it is assumed that power is supplied as shown in the voltage-current characteristic diagram of FIG. 7, for example. That is, for the high-voltage power supply unit 47, a low-current high-voltage power supply whose voltage does not enter the ignition region S and which has a voltage of 6.5 KV and a current of 50 μA is used. The boundary line of the ignition region R is obtained by an experiment result by the inventors and is a curve represented by the product of voltage and current.

FIG. 8 is an exploded perspective view of the front chamber 13, in which a cylindrical duct 52 for introducing dust-containing gas is provided on the front surface of the chamber body 51, and inside the chamber body 51,
A collision plate 53 is provided to prevent spatters such as welding fumes, which are solid substances and combusted substances, from flowing into the main chamber 11. This collision plate 53 is a handle 54
Attached to the frame 55 with the chamber main body 51
It can be inserted and removed freely. Further, in the lower part of the chamber body 51, water W for extinguishing the spatter that has collided with the collision plate 53 and dropped is contained in the pallet 56. Handles 57 and 58 are attached to the pallet 56, and the pallet 56 can also be inserted into and removed from the chamber body 51.

Here, the collision plate 53 is provided on the flow axis of the dust-containing gas and collides with the spatter. The collision part 53a is provided so as to project from the side edge of the collision part 53a toward the front so that the spatter is scattered. Side plates 53b to 53e for preventing the above are provided. These side plates 53b to 53e are shown in FIG.
As shown in FIG. 3, the collision portion 53a is opened outward with an opening E and the collision portion 53a has its center at the duct 5a.
The side plate 53b side of the upper part is separated by a distance F from the rear end part of 2, and the upper side plate 53b side is inclined by the inclination D with respect to the vertical direction.

The opening E of the collision plate 53 is set to 120 °
When the gradient D was set to 30 ° and the pressure loss with respect to the distance F was calculated, the characteristics shown in FIG. 10 could be obtained. Further, when the spatter was collided with the collision plate 53 and the spatter recovery rate with respect to the distance F was obtained, the characteristics shown in FIG. 11 were obtained. From these characteristics, the opening E is 105 to 135 ° and the gradient D is 25 to 35.
And the distance F is preferably about 170 to 220 mm.

This embodiment is constructed as described above, and the charging unit 23 is supplied with power via the high voltage supply insulator 27.
Electric power is supplied to the dust collection unit 24 through a high-voltage supply insulator 28. A voltage is further applied from the high voltage supply insulator 28 to the high voltage electrode plate 33 via the conductive spring 46, the conductive screw 45, the power feeding shaft 35 and the pipe-shaped cover 34. As a result, a corona discharge is generated between the ionization line (not shown) and the ground electrode in the charging unit 23, and the dust collecting unit 24
Then, an electric field is formed between the high voltage electrode plate 33 and the ground electrode plate 32.

In this state, the suction fan operates and dust-containing gas flows from the duct 52 of the front chamber 13 to the chamber body 51.
When flowing in, the dust-containing gas collides with the collision plate 53 and bypasses the collision plate 53 and flows into the main chamber 21.
At this time, when the dust-containing gas contains spatter like welding fumes, the spatter collides with the collision plate 53 and falls into the water W in the pallet 56. As a result, the spatter is removed from the dust-containing gas, and the sputter removes water W.
Extinguished by.

On the other hand, the dust-containing gas bypassing the collision plate 53 is
After flowing into the main chamber 11 and undergoing corona discharge in the charging unit 23, an electric charge is given to the dust in the dust-containing gas. The charged dust subsequently flows between the high voltage electrode plate 33 and the ground electrode plate 32 of the dust collection unit 24 and is collected by the ground electrode plate 32 having the opposite polarity. Then, the clean gas from which the dust has been removed flows out from the outlet 21c.

Here, the collecting portion 33a and the spacer 33b of the high-voltage electrode plate 33 are formed of a semi-insulating resin material, and the pipe-shaped cover 34 is also formed of a material equivalent to that of the high-voltage electrode plate 33. Even if the dust-containing gas contains oil mist, water-soluble oil mist, welding fume, etc. and contains water and conductive dust, the movement of the charge of the high voltage electrode plate 33 is limited by the electric resistance of the semi-insulating resin material. Because
Sparks are not generated between the high-voltage electrode plate 33 and the ground electrode plate 32, and the collected dust is not ignited, and the dust collection efficiency can be excellently maintained. Further, since it is almost unnecessary to divide the high-voltage electrode plate 33 and the ground electrode plate 32 or to install a resistor as a separate body, the size can be reduced.

Furthermore, in the dust-containing gas flow section, the power supply shaft 35 is covered with a high-voltage electrode plate 33 and a pipe-shaped cover 34 which are made of a semi-insulating resin material and an equivalent material, and the pipe-shaped cover 34 and the insulator. Since 41 is sealed by the O-ring 37 and the O-rings 42 and 43, a large current due to a creeping leak current due to moisture or conductive dust does not occur, and sparks can be stably prevented over time. The dust collection efficiency can be kept excellent.

Further, since the high-pressure supply insulator 28 is completely isolated from the dust-containing gas flow section by the partition wall 40, the high-pressure supply insulator 28 is prevented from adhering moisture or conductive dust to the high-pressure supply insulator 28. Insulation failure does not occur.

Furthermore, since solids and the like are removed by the collision plate 53, they hardly flow into the dust collecting unit 24.

Further, if a water level gauge for detecting the height of the water W is provided on the pallet 56, the amount of the water W can be constantly checked, and the water level can be controlled by using the output of the water level gauge. The main chamber 21 can be automatically controlled.

[0038]

As described above, in the electrostatic precipitator according to the present invention, the high-voltage electrode plate of the dust collecting part is molded from a semi-insulating resin material and arranged around the power supply shaft, and the ground electrode plate is also the same.
Since it is placed around the power supply shaft in the
Can be realized and downsizing can be realized. In addition, semi-insulating resin material
The resistance of the
The high voltage power supply supplies excessive power to prevent
Since it is not necessary to prevent the generation of sparks even if water or conductive dust flows in, the dust collection effect can be kept high.

Furthermore, if a collision plate is installed upstream of the dust collecting unit,
For example, it is possible to prevent the solid matter from flowing into the dust collecting portion, and when the solid matter is a combustion material, it is possible to prevent ignition of dust in the dust collecting portion.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment.

FIG. 2 is a perspective view of a main chamber.

FIG. 3 is a partially enlarged perspective view of a dust collection unit.

FIG. 4 is a partially enlarged cross-sectional view of a dust collection unit.

FIG. 5 is a graph showing characteristics of a semi-insulating resin material.

FIG. 6 is a power supply circuit diagram of an electrode plate.

FIG. 7 is a graph showing voltage-current characteristics.

FIG. 8 is an exploded perspective view of the front chamber.

FIG. 9 is a sectional view.

FIG. 10 is a graph showing pressure loss due to a collision plate.

FIG. 11 is a graph showing the recovery rate by the collision plate.

FIG. 12 is a power supply circuit diagram of an electrode plate of a conventional example.

FIG. 13 is a graph showing voltage-current characteristics of a conventional example.

[Explanation of symbols]

11 Main chamber 12 Control unit 13 front chamber 23 Charging unit 24 Dust collection unit 32 Ground electrode plate 33 High voltage electrode plate 47 High-voltage power supply 53 collision plate 56 pallets

─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Masaji Ataka 8-37-10 Aoyagi, Soka City, Saitama Prefecture (56) References JP-A-2-218454 (JP, A) JP-A-58-20251 (JP, A) ) JP-A-57-21950 (JP, A) JP-A-5-38412 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B03C 3/00-3/88

Claims (3)

(57) [Claims] 1. A charged portion for giving an electric charge to dust in a dust-containing gas, and a high voltage electrode plate and a ground electrode plate are alternately arranged in parallel at a predetermined interval downstream of the charged portion to discharge the charged dust. Electric cou
In the electrostatic precipitator having a dust collector that collects by a long force, the high-voltage electrode plate is made of a semi-insulating resin material and has a high electric power.
A power supply shaft is provided around the power supply shaft that supplies pressure.
The grounding electrode plate is made of a conductive material.
Do not touch the power supply shaft around the power supply shaft.
And the high voltage power supplied to the high-voltage electrode plate via the power supply shaft is limited to a level such that the dust adhering to the electrode plate does not ignite. apparatus. Wherein electric dust collector of claim 1, characterized in that the impingement plate for removing solids contained in the dust-containing gas, was placed upstream of the charge section. 3. The electrostatic precipitator according to claim 2 , wherein the collision plate is arranged so as to be inclined so that the collided solid matter falls downward.