JPH0871451A - Electrostatic precipitator - Google Patents

Abstract

PURPOSE: To prevent the generation of spark discharge between electrodes and to economically stably restrain the lowering of dust collecting performance by constituting high voltage side electrodes of a hygroscopic resin of a prescribed volume resisitivity. CONSTITUTION: High voltage side electrodes 31 -3n in an electrostatic precipitator are constituted of a hygroscopic resin having volume resistivity of the order of 10<10> -10<13> Ωcm. Further, the hygroscopic resin shows semi-insulation property by its absorbed moisture, and the mixed quantity of the hygroscopic resin is adjusted, whereby its volume resistivity is freely adjusted. In this way, in the high voltage side electrodes 31 -3n of a collector, since the volume resistivity of the resin electrodes is maintained within a range of 10<8> -10<13> by the moisture absorbed by the hygroscopic resin mixed in the resin, the transfer of electric charge is restricted in the resin electrodes to restrain the generation of spark discharge. Further, because of the restriction of the charge transfer, collector leak current is reduced to cause no voltage drop thereby maintaining high voltage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic dust collector,
More specifically, it relates to a high-voltage side electrode of a collector section for collecting charged fine particles floating in an air flow.

[0002]

2. Description of the Related Art An electrostatic precipitator gives an electric charge to fine particles in an air stream by corona discharge or the like, and collects and removes the charged particles by electrostatic force while the charged particles pass through an electric field. However, various types are used from large industrial equipment to small household equipment.

A conventional collector uses an aluminum parallel plate type electrode, and generally, a high-voltage side electrode connected to the positive (high-voltage) side of a high-voltage power source and a dust collector connected to its negative (ground) side. The electrodes and electrodes are arranged in parallel alternately, and both the high-voltage side electrode and the dust collecting electrode are made of aluminum flat plates.

[0004]

However, in the collector of the electrostatic precipitator using the conductive metal as the electrode as described above, when the conductive particles are mixed in the charged particles guided to the collector, Spark discharge between the electrodes was unavoidable, for example, spark discharge occurred between the electrodes on the high-voltage side and the dust collecting side, and the resistance decreased due to the accumulation of collected dust on the electrodes, resulting in spark discharge. Also, the insulating parts and spacers that hold these electrodes become dirty, and the resistance decreases due to humidity, so that collector leak current starts flowing from the parts that are in contact with the electrodes, reducing the voltage. However, there was a drawback in that the collection performance was lowered. Further, there is a problem that the pressure loss of the air flowing between the electrodes is large due to the spacers between the electrodes and the like.

Therefore, an object of the present invention is to provide an electrostatic precipitator capable of preventing the occurrence of spark discharge between electrodes and stably suppressing the deterioration of the collecting performance with the passage of time.

[0006]

SUMMARY OF THE INVENTION The present invention is a collector including an ionizer section for giving an electric charge to fine particles in an air stream, a dust collecting side electrode for collecting charged particles by an electrostatic force, and a high voltage side electrode. Of the semi-insulating resin, wherein the high-voltage side electrode has a volume resistivity value of the order of 10 ¹⁰ to 10 ¹³ Ωcm at a temperature and humidity of a use environment. Is an electrostatic dust collector.

Further, the hygroscopic resin used for the high-voltage side electrode is a resin having a volume resistivity value satisfying the following expression 2.

ΔlogR / ΔlogV ≧ −1 Expression 2 In Expression 1, R is a volume specific resistance value, and V is an applied voltage.

Further, the hygroscopic resin used for the high voltage side electrode of the electrostatic precipitator of the present invention is a resin prepared by blending a water absorbent resin with ABS resin as a base material or a resin with a phenol resin as a base material. Is characterized by.

Further, the present invention has a structure in which a high voltage is supplied to a portion of the collector portion which holds the high voltage side electrode, and has a high voltage side electrode to which a voltage is applied by the holding portion. The electrostatic precipitator is provided with a collector portion, and the high voltage side electrode of the electrostatic precipitator of the present invention is a high voltage ladder type electrode integrally formed.

In order to prevent spark discharge between electrodes and to obtain high trapping performance, a high voltage is applied to the electrodes, an electric field is prevented from being localized on the electrodes, and an excessive electric field is applied to the electrodes. It is thought that current must be prevented from flowing. Therefore, by making the electrode semi-insulating, it is possible to limit the instantaneous movement of electric charge on the electrode and suppress the occurrence of spark discharge. When the volume resistivity of the electrode and the presence or absence of sparks were examined, it was found that when the volume resistivity of the electrode was less than 10 ⁸ Ωcm, a spark discharge tended to occur between the high voltage side and the dust collecting side electrodes. Further, when the volume resistivity value exceeds 10 ¹³ Ωcm, the dust collection efficiency tends to decrease. Therefore, the volume resistivity is in the range of 10 ⁸ to 10 ¹³ Ωcm,
In particular, when an electrode in the range of 10 ¹⁰ to 10 ¹³ Ωcm is used, spark discharge does not occur, and an excellent dust collecting performance can be obtained. Further, in consideration of the number of steps for assembling the electrode and the reliability of the electrode, it is preferable to integrally form the electrode by using the semi-insulating resin having the above-mentioned volume resistivity.

In order to prepare such a resin for semi-insulating electrode, (1) carbon black,
It is considered that it can be obtained by mixing an appropriate amount of a conductive material such as (2) carbon fiber, (3) conductive or semi-conductive whisker, and (4) stainless fiber. However, when I actually went, the resistance value was 10 ⁶ Ωc
A resin having a relatively low value, such as m or less, can be easily obtained, but it was extremely difficult to prepare a resin having a target resistance value in the order of 10 ¹⁰ to 10 ¹³ Ωcm. This is probably due to the following reasons. That is, (1) In order to prepare a resin having a high resistance value, it is not possible to add a large amount of conductive material to the resin as is usually done, and the resistance value of the resin can be controlled with a small amount of conductive material. Must. However, when the amount of the conductive material added to the resin is small, the change in the resistance value with respect to the added amount is large, and even if the amount of the conductive material is slightly changed,
This results in a large change in the resistance value of the resin. Furthermore, the resistance value may change significantly due to slight differences in the dispersed state of the conductive material in the resin, so that a stable resistance value cannot be obtained. Further, (2) when the electrode is molded, a resin layer containing no conductive material is formed on the surface of the electrode, and the thickness of the resin layer greatly changes depending on molding conditions.
This is because it causes the resistance value to change.

Further, in a resin in which a certain amount of a conductive material is mixed and the resin layer on the resin surface formed by molding is scraped off to expose a portion containing the conductive material, the resistance value cannot be kept within a certain range. Although possible, the resistance value of the resin exhibits a voltage dependence that changes depending on the voltage applied to the resin. That is, when the potential gradient applied to the resin is small, it exhibits a high resistance value, and when the potential gradient is large, it exhibits a low resistance value, and when a voltage higher than a certain voltage is applied, a short circuit suddenly occurs. Therefore, when an electrode having a resistance value within the above range is made of such a resin, spark discharge occurs when the high-voltage side electrode and the ground side electrode are bridged by a conductive substance. Further, it has been found that there is a problem that the resin deteriorates when a short circuit occurs at a certain voltage or more, and the original resistance value does not return even if the voltage is removed.

Therefore, in order to obtain a resin having a high resistance, it is not achieved by adding a very small amount of a conductive material having an electric conductivity different by 10 digits or more to the originally insulating resin, and the water adsorbed by the resin is not added. Paying attention to that the resistance value of the resin changes due to
It was found that by controlling the hygroscopicity of the resin, the resistance value of the resin can be set in the range of 10 ¹⁰ to 10 ¹³ Ωcm even at high voltage, and based on this finding, the electrostatic precipitator An electrode using a hygroscopic resin can be used as the high-voltage side electrode, and the present invention has been completed.

The present invention will be described in detail below.

The hygroscopic resin which can be used in the present invention has hygroscopicity and is 10 ⁸ to 10 ¹³ Ωcm, preferably 10 ¹⁰ to ¹⁰ to high voltage at the temperature and humidity of the use environment.
A resin having a volume resistivity value in the order of 10 ¹³ Ωcm can be used. Such a hygroscopic resin has hygroscopicity in the resin itself, and it is possible to use one having the above-mentioned volume resistivity value, for example, by adding a water absorbent resin to a resin base material such as a thermoplastic resin, A resin having hygroscopicity can be used by blending. Such a resin shows a semi-insulating property due to the water absorbed by the water-absorbent resin mixed in the resin, and by adjusting the blending amount of the water-absorbent resin,
It is a preferable resin because the volume resistivity of the resin can be freely adjusted so as to be in the range of 10 ⁸ to 10 ¹³ Ωcm. Generally, the blending amount is 5 to 50% by weight, although it varies depending on the type of resin. Examples of the resin base material include thermoplastic resins such as ABS resin, polyester resin, and acrylic resin. Particularly, when ABS resin is used as the base material, it has excellent moldability, flame retardancy, heat resistance, and impact resistance. Can be obtained, and the manufacturing cost is low.
In addition, examples of the resin base material in which the resin itself has hygroscopicity include phenol resin, melamine resin, urea resin and the like. Further, as an example of such a thermosetting resin,
Above all, when phenolic resin is used as a base material,
A desired resistance value is easily obtained, and a preferable result is obtained. On the other hand, as the water-absorbent resin to be mixed, there are acrylate-based, Povar-based, polyamide-based, etc., and they are selected in consideration of the water-absorbing ability, the durability of the resistance value and the compatibility with the base resin. As such a hygroscopic resin, for example,
Commercially available products such as Maxloy (trade name, manufactured by JSR) and Sumilite (trade name, manufactured by Sumitomo Bakelite) can be used.

The hygroscopic resin thus prepared is
For example, in the case of a resin containing ABS as a resin base material and a water-absorbent resin, a sufficiently dried resin plate (thickness 2
mm) in a thermo-hygrostat at a temperature of 70 ° C and a humidity of 65%.
Moisture absorption after standing for 8 hours is 0.7 to dry resin.
It was 1.5% by weight, and the volume resistivity value of the resin after returning to a normal atmosphere and allowed to stand for a certain time (48 hours or more) showed an order of 10 ¹⁰ to 10 ¹³ Ωcm.

Similarly, in the case of a phenol resin,
The volume resistivity value was on the order of 10 ¹² to 10 ¹³ Ωcm.

Next, the properties of the hygroscopic resin required for the electrode based on the relationship between the resistance value and the applied voltage will be described with reference to FIG.

FIG. 1 is a graph showing the change in the volume resistivity of the resin when the voltage applied to the resin electrode is changed. From this graph, the applied voltage V and the volume resistivity R
Then, the common logarithm is taken, and the slope K defined by Equation 3 is obtained. The obtained slope K is shown in Table 1.

K = ΔlogR / ΔlogV Equation 3 The fact that the slope K is smaller than −1 means that the resistance value is greatly reduced when the applied voltage is increased, and the movement of electric charges is facilitated and spark discharge is likely to occur. In fact, in the resin mixed with the conductive material shown in Experimental Examples 3 and 4, the slope K shows a large voltage dependence at a value of −2 to −3, and is 7 to 8 kV.
Spark discharge is occurring at the voltage. Therefore, any resin can be used as the electrode of the present invention as long as the volume resistivity of the resin does not greatly decrease due to the increase of the applied voltage. For this purpose, it is necessary that the value of the slope K be −1 or more. That is, if the slope K has a value of -1 to 0, the voltage dependence of the volume resistivity is small, and the volume resistivity does not decrease to such an extent that a spark discharge occurs due to an increase in the applied voltage and a current flows. When the applied voltage is increased, the volume resistivity value is 0 or more.
On the contrary, the voltage will increase, and a higher voltage can be applied between the electrodes to improve the collection efficiency. Therefore, if the value of the resin inclination K is -1 or more, an electrode in which no spark discharge occurs between the electrodes can be obtained, and stable collection performance can be secured. Good results are obtained by using a resin having a slope K of 6 or more.

Using these resins, the electrode can be integrally formed by casting, compression molding, injection molding or the like in the case of a thermosetting resin and injection molding or the like in the case of a thermoplastic resin. Various shapes such as a flat plate shape and a ladder type can be used as the shape of the electrode. Particularly, when a ladder type electrode is used, favorable results can be obtained in terms of dust collection performance and assembly man-hours.

The electrode made of the hygroscopic resin of the present invention is used for the electrode on the high voltage side, and the electrode on the dust collecting side is made of a metal such as aluminum having high conductivity or a conductive resin. The reason for this is that if the electric resistance of the dust collecting side electrode is high, the charges from the collected charged particles will accumulate on the dust collecting side electrode.
This is because the accumulated charge acts to cancel the electric field between the electrodes on the high voltage side and the dust collecting side, and as a result, the collection efficiency at the dust collecting side electrode tends to decrease.

When a flat electrode is used, for example,
The high-voltage side resin electrodes and the ground side dust collecting side aluminum electrodes are alternately arranged in parallel, and each electrode is fixed by an insulating spacer or the like so as to maintain the electrode interval. When a ladder type electrode is used, for example, as shown in FIG. 2, the dust collecting side electrode and the high voltage side ladder electrode are combined.

FIG. 2 is an exploded perspective view showing the structure of the collector portion when a ladder type electrode is used. In the figure, reference numeral 1 is a high-pressure side ladder, and reference numeral 2 is a dust collecting electrode plate. The high-pressure side ladder 1, a plurality of high voltage side electrode 3 ₁ -
3 _n is formed, also, a plurality of dust-collecting-side electrode 4 ₁ ~4 _n-1 to the collecting electrode plates 2 are formed. The high voltage side ladder 1 and the dust collecting electrode plate 2 are combined, and the dust collecting side electrodes 4 ₁ to 4 _n-1 are inserted between the high voltage side electrodes 3 _{1 to} 3 _n to form a collector portion.

When the semi-insulating electrode made of the hygroscopic resin of the present invention is used, in order to prevent the voltage drop of the parallel plate type high voltage side electrodes and the ladder type high voltage side electrodes 3 _{1 to} 3 _n , The high-voltage side electrode must not contact the ground-side electrode, and even if it is an insulator that is not grounded, it must be avoided to contact the high-voltage side electrode. That is, these insulators are indirectly grounded through the surfaces of the insulators such as the collector portion, the frame of the dust collector, and the case, and a potential drop occurs. This is a phenomenon that occurs because the resistance value of the high-voltage side electrode is high. If the high-voltage side electrode is a conductor, no potential drop occurs even if the insulator contacts. Further, when the surface of the insulator becomes dirty and becomes moist, the potential drop is further amplified. However, on the other hand, the high voltage side electrode must be held somewhere.
To this end, the above problem can be solved by adopting a structure in which a high voltage is supplied to the portion holding the high voltage side electrode. With such a configuration, the entire high-voltage side electrode can have the same high potential, a potential difference does not occur between the electrode parts, and a collector leak current does not flow, and a stable state can be maintained. Therefore, it is possible to obtain an electrostatic precipitator which is not affected by dirt and moisture and can exhibit not only the initial collection performance but also the collection performance over time.

Although heat resistance may be required depending on the electrostatic precipitator, at this time, an inorganic filler such as glass fiber treated with a silane coupling agent or the like is further added to the resin. The heat distortion temperature can be improved. In the case of the ABS type, the temperature is raised to 110 ° C. by adding glass fiber. In addition, a flame retardant or the like can be added to the resin if necessary.

The electrostatic precipitator is composed of a collector section using the high-voltage side electrode of the present invention and an ionizer section which normally gives an electric charge to the particles in the air flow. How to arrange such a structure In other words, the shape, size and arrangement of the electrodes, the method of supplying power to the electrodes, etc. are appropriately determined depending on the application and type of the electrostatic precipitator.

[0029]

According to the structure of the present invention, in the electrode on the high voltage side of the collector, the volume specific resistance of the resin electrode can be maintained in the range of 10 ⁸ to 10 ¹³ by the water absorbed by the water absorbing resin mixed in the resin. Therefore, the movement of the charge is restricted at the resin electrode, and the spark discharge is suppressed. Further, since the movement of charges is limited, the collector leak current is also reduced, and a high voltage is maintained without a voltage drop.

Hereinafter, the present invention will be described in more detail with reference to experimental examples and examples.

[0031]

【Example】

Experimental Example 1 Absorbent resin in which ABS resin is mixed with water absorbent resin as electrode material (moisture absorption amount: 1.3% by weight, temperature 25 ° C, humidity 60%
Volume resistivity at applied voltage of 500 V: 6 × 10 ¹¹ Ω
cm, product name: Maxloy S704HW, manufactured by JSR)
Was used to prepare a flat plate electrode having a length of 10 cm, a width of 10 cm and a thickness of 2.5 mm. As shown in FIG. 3a, when a voltage applied to the resin electrode is changed and a metal ball having a diameter of 6 mm is brought into contact with the resin electrode, a spark discharge is generated between the resin electrode and the metal ball. The voltage at which The results are shown in Table 1. Also, ASTM-D
Based on 257, the voltage applied to the resin electrode sample was changed and the volume resistivity of the resin electrode was determined as shown in FIG. 3b. The results are shown in Table 1 and FIG.

Experimental Example 2 Hygroscopic resin made of phenolic resin as electrode material (moisture absorption: 1% by weight, temperature 25 ° C., humidity 60%, applied voltage 500
Volume resistivity at V: 3 × 10 ¹² Ωcm, trade name:
Using Sumilite PLC2147, manufactured by Sumitomo Bakelite Co., Ltd., an electrode having the same size as that of Experimental Example 1 was prepared, and Experimental Example 1
It evaluated similarly to. The results are shown in Table 1 and FIG.

Experimental Example 3 Semiconductive resin (moisture absorption: 0.5) prepared by mixing conductive whiskers with PBT resin as an electrode material (mixing amount: 15% by weight).
Weight% or less, temperature 25 ° C., humidity 60%, volume resistivity at applied voltage 500 V: 1.3 × 10 ¹¹ Ωcm),
An electrode having the same size as in Experimental Example 1 was produced and evaluated in the same manner as in Experimental Example 1. The results are shown in Table 1 and FIG.

Experimental Example 4 Semi-conductive resin (moisture absorption: 0.5) obtained by mixing conductive whiskers with PBT resin as an electrode material (mixing amount: 10% by weight).
Weight% or less, temperature 25 ° C., humidity 60%, volume resistivity at applied voltage 500 V: 4.3 × 10 ¹³ Ωcm),
An electrode having the same size as in Experimental Example 1 was produced and evaluated in the same manner as in Experimental Example 1. The results are shown in Table 1 and FIG.

[0035]

[Table 1]

Example 1 Length 19 cm, width 10 c prepared in the same manner as in Experimental Example 1.
m, a 1 mm thick resin flat plate electrode was used as a high voltage side electrode, and a 1 mm thick aluminum flat plate electrode was used as a dust collecting electrode and were arranged in parallel to each other as shown in FIG. 3c (electrode interval: 7.
5 mm), a dust collector was produced. Then, the collection performance of this dust collector was measured according to the method of JIS B9908 type-1. The measurement was conducted with a collector voltage Vc of 2.2 kV, an ionizer voltage Vi of 4.6 kV, and a wind speed of 1 m /
Seconds, using DOP aerosol as the test aerosol,
The evaluation particle size was 0.3 μm and the collection rate was measured. Also,
For comparison, a normal ABS resin containing no water-absorbent resin in the high-voltage side electrode (generally, water absorption: 0.5 wt% or less, volume resistivity: 10 ¹⁴ Ωcm or more, for example, trade name: ABS15, JSR (Comparative Example 1) and a case of using an aluminum plate (Comparative Example 2) were evaluated. Table 2 shows the results.

[0037]

[Table 2]

Example 2 Using the hygroscopic resin of Experimental Example 1, the ladder-type electrode shown in FIG. 2 was injection-molded under the same conditions as in Experimental Example 1, and carbon fiber was compounded on the high-voltage side of this electrode. A dust collector was produced using a conductive resin as the dust collecting side electrode so that the collector depth d was 9 mm and the collector pitch was 2.9 mm. Then, the collection performance of the dust collector is set to 2.3 for the collector voltage Vc.
The collection rate was measured by setting the kV and the ionizer voltage Vi to 4.6 kV, using a wind velocity of 1 m / sec, and using DOP aerosol as a test aerosol, with an evaluation particle size of 0.3 μm.
In addition, as a comparison, the normal A
A ladder type electrode was prepared using BS resin and evaluated in the same manner (Comparative Example 3). The results are shown in Table 3.

[0039]

[Table 3]

Example 3 A hygroscopic resin obtained by mixing a water absorbent resin with an ABS resin as an electrode material (moisture absorption amount: 0.9% by weight, temperature 25 ° C., humidity 60%
Volume resistivity at applied voltage of 500 V: 3 × 10 ¹³ Ω
cm, product name: Maxloy HN-901, manufactured by JSR)
Using a parallel plate type electrode (length 46c shown in FIG. 3 (c).
m, width 10 cm, thickness 1.5 mm) was produced. Next, using this electrode as the high voltage side and aluminum as the dust collecting side electrode (thickness 0.5 mm), a dust collecting apparatus was produced with a collector depth d of 100 mm and a collector pitch of 6 mm. Next, the collection performance of the dust collector is adjusted to the collector voltage Vc.
Is 8 kV, the ionizer voltage Vi is 6 kV, the wind speed is 1 m / sec, DOP aerosol is used as the test aerosol, the evaluation particle size is 0.3 μm, and the collection rate is 90%. It was

Assuming that the high voltage electrode and the grounding body are in contact with each other, Table 1 shows that when a high voltage is applied to the resin and a metal ball having a diameter of 6 mm is brought into contact with the resin, sparks are generated between the electrodes. The voltage at the time of discharge is measured. In Experimental Examples 3 and 4, the insulation was broken at about 7 to 8 kV and spark discharge occurred, whereas in Experimental Examples 1 and 2, 20
No spark discharge occurred even when kV was applied. Normally 20 kV
Since it is rare to apply a voltage exceeding the above, it is possible to manufacture an electrode in which substantially no spark discharge occurs.

Further, according to the result of FIG. 1 showing the change of the volume resistivity when the applied voltage is changed, in the experimental examples 1 and 2 of FIG. Although the values were obtained, Experimental Examples 3 and 4
In, the resistance value is changed by 2 to 3 digits or more depending on the applied voltage. From this fact and the experimental results in Table 1, spark discharge occurs in the resin that has a large resistance change rate with respect to the applied voltage and a low resistance when the applied voltage increases, and conversely, the resistance value is small and the resistance value is as described above. It can be seen that spark discharge does not occur in the resin remaining within the range.

This is because the amount of the conductive material in the resin is small in the resin to which the conductive material is added, and the conductive material is not dispersed in a continuous state but the conductive material is separated by the resin. Dispersed throughout. Therefore, when the potential gradient inside the resin becomes large, it becomes easy for the electric charges to move between the conductive materials isolated by the resin, so that the current easily flows and the resistance value of the resin also decreases, resulting in a large voltage dependence. Showing sex. On the other hand, in a hygroscopic resin, the moisture absorbed by the resin contributes to the conductivity, and this moisture exists almost continuously in the resin and is easy to move. Is less than that of the conductive material-added resin. Furthermore, with the hygroscopic resin, when the voltage increases,
An electric current will flow, but when the electric current flows, Joule heat is generated, and the Joule heat evaporates a small amount of water adsorbed on the resin, resulting in an increase in resistance, resulting in a high resistance value. Can be maintained.

As described above, in the conductive material-added resin, the resistance decreases when the voltage applied to the electrode increases, the current flows more easily when the resistance decreases, and the resistance further decreases when the current easily flows, and finally the spark is generated. Discharge will occur.

On the other hand, in the case of the hygroscopic resin, since a high resistance value is maintained even if a high voltage is applied to the electrodes,
It is thought that spark discharge is not good. Further, the high resistance value limits the movement of charges, and the collector leakage current is extremely small so that no voltage drop occurs. As described above, it is understood that the small change in the resistance value with respect to the voltage is important for ensuring stable collection performance.

Furthermore, when an electrode is made of the hygroscopic resin of the present invention, the collector leakage current is extremely small, and therefore the collection performance does not deteriorate even in a high humidity environment.

From the results shown in Table 2, the resin electrode made of the hygroscopic resin of the present invention has a trapping efficiency almost equal to that of the aluminum electrode and is an excellent electrostatic dust collector without spark discharge. Recognize. Furthermore, since the electrodes can be formed by integral molding using a hygroscopic resin, the metal surface is not exposed due to the dielectric breakdown found in electrodes with semiconductive surface treatment on metal plates. In addition, the stable electrode state is maintained, and the dust collecting ability does not decrease with time.

Further, when the ladder type high voltage side electrode as in Example 2 of Table 3 is used, an electrostatic precipitator having a depth of 9 mm and an extremely thin thickness and excellent collecting ability can be obtained. . Further, by increasing the depth as in Example 3, a higher collection rate can be obtained.
Furthermore, since the ladder-type electrode can be manufactured by integrally molding a hygroscopic resin, the man-hours at the time of assembly processing can be reduced, and the manufacturing cost can be reduced. In addition, as shown in FIG. 2, when a dust collecting electrode is combined, a spacer or the like for holding the electrode interval is not necessary, and the problem of pressure loss can be solved.

Further, since such a ladder type electrode takes advantage of the parallel plate type collector, the contamination performance due to dirt and moisture does not progress and the collecting performance does not deteriorate.

[0050]

According to the present invention, there is provided an electrostatic precipitator which does not generate a spark discharge between collector electrodes, has a very small collector leak current and is stable with time and has an excellent collecting performance. be able to.

[Brief description of drawings]

FIG. 1 is a graph showing a change in volume resistivity of a resin with respect to an applied voltage of the resin.

FIG. 2 is an exploded perspective view showing an example of a configuration of a collector section using a ladder type electrode.

FIG. 3 is a diagram showing an evaluation test method, in which (a) is a circuit diagram for evaluating the relationship between an applied voltage and spark discharge;
(B) is a circuit diagram for measuring a volume resistivity with respect to an applied voltage, and (c) is a diagram showing an arrangement of electrodes of a parallel plate collector.

[Explanation of symbols]

1 high pressure ladder 2 collecting electrode plates 3 ₁ to 3 _n high voltage side electrode 4 ₁ to 4 _n-1 collection electrode d Depth

Claims (2)

[Claims] 1. An electrostatic precipitator having an ionizer section for giving an electric charge to fine particles in an air stream, and a collector section provided with a dust collecting side electrode for collecting the charged particles by an electrostatic force and a high voltage side electrode. An electrostatic precipitator in which the high-voltage side electrode is made of a hygroscopic resin having a volume resistivity of the order of 10 ¹⁰ to 10 ¹³ Ωcm. 2. The hygroscopic resin used for the high-voltage electrode is
A resin whose volume specific resistance value satisfies the following formula 1.
The electrostatic precipitator described in. ΔlogR / ΔlogV ≧ −1 Expression 1 However, in Expression 1, R is a volume specific resistance value, and V is an applied voltage.