JPH0541784Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an electrostatic precipitator, and particularly to an electrostatic precipitator equipped with a leakage detection function of a discharge electrode supporting insulator.

[Conventional technology]

Normally, an electrostatic precipitator collects dust in a dust-containing gas flowing into a dust collection chamber by electrostatically charging the dust collection electrode by corona discharge generated between a discharge electrode and a dust collection electrode installed in the chamber. It is adsorbed and collected.

Since a high DC voltage is applied to the discharge electrode of such an electrostatic precipitator, the discharge electrode is formed into a hollow truncated cone shape in an insulator chamber provided outside the casing body of the electrostatic precipitator. The discharge electrode is supported and insulated within the dust collection chamber by a supporting insulator. Furthermore, due to the structure of the device, a part of the discharge electrode support insulator is exposed to the dust-containing gas in the dust collection chamber.
Dust of dust-containing gas begins to adhere to its surface. The apparent electrical resistance of the dust attached to the discharge electrode supporting insulator is the electrical resistance of the insulator (approximately 10 ⁹ to 10 ¹¹
If the resistance is lower than Ωcm), the apparent electrical resistance of the discharge electrode supporting insulator becomes low, causing insulation failure. As a result, a leakage current flows through the surface of the discharge electrode supporting insulator, resulting in a short circuit state.
In such a state, a predetermined dust collection electric field is no longer generated between the discharge electrode in the dust collection chamber and the dust collection electrode, reducing the dust collection efficiency, and the discharge electrode support insulator may be damaged due to Joule heat. There is a risk of damage.

Furthermore, when the discharge electrode supporting insulator is kept at a low temperature, moisture in the dust-containing gas condenses on the surface, resulting in poor insulation as described above.

Therefore, an electric dust collector that is configured to prevent such insulation failure of the discharge electrode support insulators has been developed and put into practical use.

FIG. 3 shows a sectional view of the overall configuration of this type of electrostatic precipitator. A discharge electrode 6 and a dust collection electrode 8 are provided in the dust collection chamber 2, and the introduced dust-containing gas X passes between the discharge electrode 6 and the dust collection electrode 8, and flows out as clean gas Y outside the room. An insulator chamber 4 is provided outside the upper part of the dust collection chamber 2, and a discharge electrode supporting insulator 14 of this chamber 4 is installed so as to be connected to an insulator protection stool 12, and its upper end is covered by an insulator cover 16. It's blocked. A support 10 that supports the discharge electrode 6 so as to be disposed in the dust collection chamber 2 is inserted through the center of the insulator cover 16, and a plurality of fluid intake holes 18, 18 are formed around the center. There is. Further, a heating device 20 is arranged around the lower end of the discharge electrode support insulator 14.

A through-hole insulator 22 is provided on the side wall of the insulator chamber 4,
A feeder wire 26 that connects a high-voltage power source 24 provided outside the insulator chamber 4 and the support body 10 is inserted through the through-hole insulator 22 . Further, a fluid intake port 28 is formed in the side wall of the insulator chamber 4, and cold air (cold air) or warm air Z flows into the insulator chamber 4 through this fluid intake port 28. The cold air or hot air Z taken into the insulator chamber 4 is blown into the inside of the discharge electrode supporting insulator 14 through the blow hole 18, and further blown into the dust collection chamber 2 through the insulator protection stool 12. .

At that time, dust in the dust-containing gas X passing through the dust collection chamber 2 flows into the insulator chamber 4 and the inside of the discharge electrode supporting insulator 14 due to the sealing effect of the cold air or warm air Z passing through the insulator chamber 4. This prevents dust from adhering to the surface of the discharge electrode supporting insulator 14. Further, the surface temperature of the discharge wire support insulator 14 is always kept above the dew point by the heating device 20 in the insulator chamber 4, thereby preventing moisture from condensing on the surface of the discharge electrode support insulator 14.

[Problem that the invention seeks to solve]

However, even in the electrostatic precipitator configured as described above, poor insulation of the discharge electrode support insulator 14 can only be discovered when a large short-circuit current flows through the surface or during periodic inspection of the electrostatic precipitator. There are problems that cannot be discovered.
In addition, the insulation defect was discovered due to pressure fluctuation and temperature rise of the dust-containing gas X introduced into the dust collection chamber 2, a defect in the air blowing system that blows cold air and hot air Z into the insulator chamber 4, and operation of the heating device 10. There is a problem that can only be discovered when damage and cracks have already occurred on the surface of the discharge electrode supporting insulator 14 due to mistakes or the like.

The present invention was developed in view of the problems of the conventional technology mentioned above.
It is an object of the present invention to provide an electrostatic precipitator that can prevent damage and cracks caused by deterioration of the insulation of a discharge electrode supporting insulator.

[Means for solving problems]

In order to solve the above-mentioned problems, a dust-containing gas is introduced into the dust collection chamber of an electrostatic precipitator, and the dust in the dust-containing gas is transferred to a discharge electrode supporting insulator in an insulator chamber provided outside the dust collection chamber. An electrostatic precipitator that collects the dust by electrostatic adsorption to the dust collecting electrode by corona discharge generated between the discharge electrode supported in the dust collecting chamber and the dust collecting electrode of the dust collecting chamber. The method further comprises: an electrode section provided at the lower end of the discharge electrode support insulator through which leakage current flows to the surface of the discharge electrode support insulator; and a leakage detection device configured to detect the leakage current flowing through the electrode section. It is characterized by

[Effect]

In the electrostatic precipitator of the present invention, the leakage current flowing on the surface of the discharge electrode supporting insulator that supports the discharge electrode flows to the electrode section provided at the lower end of this insulator.
This leakage current of the electrode portion is detected by a leakage detection device.

As a result, even if an excessive leakage current begins to flow through the surface of the discharge electrode supporting insulator as its insulation deteriorates, the condition can be detected, and damage and cracks can be prevented from occurring.

Further, according to the present invention, since the electrode section is attached to the casing of the dust collection chamber through an insulating packing, leakage current that has flowed from the discharge electrode support insulator to the electrode section is prevented from flowing into the dust collection chamber. can.

〔Example〕

Hereinafter, preferred embodiments of the electrostatic precipitator according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a cross-sectional view of the overall general structure of an electrostatic precipitator according to the present invention, and for convenience of explanation, the figure mainly shows the discharge electrode supporting insulator. In FIG. 1, the same components as in FIG. 3 are given the same reference numerals, and the explanation of the overlapping parts will be omitted.

An insulator chamber 4 is provided outside the upper surface of the casing of the dust collection chamber 2 of the electrostatic precipitator. This insulator room 4
An insulator receiver 21 is arranged on the bottom of the insulator receiver 2.
1 and the lower end of the discharge electrode support insulator 14 is provided with an insulating packing 22 which also serves as an airtight seal. Further, an electrode 23 is provided at the lower end of the discharge electrode support insulator 14, and this electrode 23 is in contact with the insulating packing 22. The electrode 23 may be replaced by, for example, a metal fitting that fixes the discharge electrode support insulator 14 onto the insulating packing 22. Electrode 23 is lead wire 2
6 to the current detection device 25.
As a result, when insulation decreases due to dust adhesion or dew condensation on the inner or outer surface of the discharge electrode support insulator 14 during operation of the electrostatic precipitator, leakage current _L flowing through the surface of the electrode 23 or the lead line 2
4 and is input to the current detection device 25.

The current detection device 25 is constituted by, for example, an electronic circuit shown in FIG. The current detection device 25 is composed of a primary circuit 29 into which the leakage current _L is input, and a secondary circuit 39 which outputs a signal according to the input current value of this circuit 29.
and the secondary circuit 39 are optically coupled by a photocoupler 38 consisting of a light emitting element (for example, a light emitting diode) 38A and a light receiving element (for example, a photodiode) 38B. Thereby, the primary circuit 29 and the secondary circuit 39 are electrically isolated.

The primary circuit 29 has current input terminals 28A, 28B,
Varistors 30, 32, resistor 34, variable resistance path 3
6 and a light emitting element 38A of a photocoupler 38. The primary circuit 29 is a varistor 30,3
2 protects against overvoltage, and input sensitivity is adjusted by variable resistor 31.

The secondary circuit 39 includes a light receiving element 38B that receives light from the light emitting element 38A, resistors 40, 42, 44, and an amplifier 46. A reference voltage obtained by dividing the power supply voltage V _C by a resistor 42 and a resistor 44 is applied to one input side of the amplifier 46, and a reference voltage obtained by dividing the power supply voltage V C by a resistor 42 and a resistor 44 is applied to one input side of the amplifier 46. voltage is applied. As a result, the amplifier 34 outputs a signal corresponding to the leakage current I _L to a separately provided alarm device, for example, via the signal output terminals 50A and 50B. Based on this signal, the alarm device notifies the operator of the quality of the insulation state of the discharge electrode support insulator 14 via a display device such as an LED.

In the electrostatic precipitator of this embodiment, the leakage potential I _L flowing on the surface of the discharge electrode supporting insulator 14 is:
Approximately several μA to several hundred μA flows during normal conditions when the insulation condition is good, and up to about 10 mA flows during abnormal conditions where insulation failure occurs.
The input sensitivity of 9 is reduced to about 1 by the variable resistor 36.
It is configured so that it can be adjusted from mA to 30mA.

Next, the operation of the electrostatic precipitator configured as described above will be described.

By applying a charging voltage to the device, dust of the dust-containing gas X introduced into the dust collecting chamber 2 is collected within the chamber 2, and thereby the cleaning gas is discharged outside the room. In addition, at that time, a part of the dust-containing gas
The dust in the dust-containing gas X flows out into the insulator chamber 4 through the blow-in hole 18, and the dust in the dust-containing gas X adheres to the surface thereof and gradually accumulates thereon. As dust accumulates on the surface of the discharge electrode support insulator 14, the electrical resistance decreases, resulting in a large leakage current I _L on the surface.
starts to flow. Also, at this time, the leakage current I _L flowing through the electrode 23 is input to the leakage detection device 25 .

As a result, the light emitting element 38A on the primary circuit 29 side of the earth leakage detection device 25 emits light according to the input current value,
According to the amount of light, the light receiving element 38 on the secondary circuit 39 side
The degree of conductivity of B changes. As the conductivity of the light receiving element 38B changes, the amplifier 46 outputs a signal corresponding to the amount of comparison with the reference voltage, and this signal is output to the outside via the signal output terminals 50A and 50B. This signal is then given to a separately provided alarm device, and the alarm device displays, for example, the insulation resistance of the discharge electrode support insulator 14 based on the input signal, or emits an alarm sound indicating a decrease in insulation as necessary. .

Incidentally, since four of the discharge electrode supporting insulators 14 are generally used per dust collection chamber, four circuits for detecting the leakage current I _L are incorporated into one printed circuit board to form a unit. It may be grounded near the chamber 4. This allows an earth leakage detection function to be added to the device at low cost.

As described above, in the electrostatic precipitator of this embodiment, leakage current flows on the surface of the discharge electrode supporting insulator 14.
I _L is an electrode 23 provided at the lower end of this insulator 14.
The current is configured to flow to the current detecting device 25 via the input current value, so that the detecting device 25 outputs a signal corresponding to the input current value. Based on the output signal from the detection device 25, the insulation state of the discharge electrode support insulator 14 can be monitored by an alarm device or the like.

As a result, the inner surface of the discharge electrode supporting insulator 14,
Insulation deterioration due to dust adhesion or dew condensation on the outer surface can be detected early during operation, and fatal accidents such as cracks and breakage of the discharge electrode support insulator 14 can be prevented.

[Effect of the invention]

As explained above, according to the electrostatic precipitator according to the present invention, the current flowing through the electrode part provided at the lower end of the discharge electrode support insulator is detected by the leakage detection device, so that the discharge electrode Leakage current in support insulators can be detected accurately. Therefore, it is possible to prevent damage and cracks from occurring due to a decrease in insulation of the discharge support insulator.

Further, according to the present invention, since the electrode section is attached to the casing of the dust collection chamber through an insulating packing, leakage current that has flowed from the discharge electrode support insulator to the electrode section is prevented from flowing into the dust collection chamber. can.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing the overall general structure of the electrostatic precipitator according to the present invention, FIG. 2 is a circuit diagram showing the structure of the leakage detection device of the electrostatic precipitator shown in FIG. 1, and FIG. FIG. 1 is a cross-sectional view showing the overall configuration of a conventional electrostatic precipitator. 2... Dust collection chamber, 14... Discharge electrode support insulator, 2
1...Insulator holder, 22...Insulating packing, 23
... Electrode, 24 ... Lead wire, 25 ... Earth leakage detection device.

Claims (1)

[Scope of claim for utility model registration] Injecting dust-containing gas into the dust collection chamber of an electrostatic precipitator,
The dust in the dust-containing gas is transferred between the discharge electrode supported in the dust collection chamber by the discharge electrode support insulator of the insulator chamber provided outside the dust collection chamber, and the dust collection electrode of the dust collection chamber. In an electrostatic precipitator that electrostatically adsorbs and collects a dust collecting electrode by corona discharge generated between the electrodes, the lower end of the discharge electrode supporting insulator is attached to the upper surface of the casing of the dust collecting chamber via an insulating packing. Additionally, an electrode portion is provided between the lower end portion of the discharge electrode support insulator and the insulating packing, through which a leakage current flows to the surface of the discharge electrode support insulator;
An electrostatic precipitator comprising an earth leakage detection device that detects the leakage current flowing through the electrode section.