JP3966551B2 - Filtration type dust collector using static electricity - Google Patents

Description

      The present invention relates to an improvement of a filtration type dust collector using static electricity.

Since the filtration type dust collector basically performs mechanical separation of powder in the filtration filter section, there is a limit to the porosity and gap size of the filter material. Blowout of powder collection occurs. In order to alleviate this phenomenon, the powder is charged in advance and the effect of collecting powder on the surface of the filter material due to the deviation of the charge release rate of the charged powder is used (for example, see Patent Document 1)
And those using the Coulomb force of charged powder (for example, see Patent Document 2). Moreover, when paying attention only to physical arrangement | positioning, there also exists an example which has arrange | positioned the electrode in the clean space side like this invention (for example, patent document 3).
JP 52-093271 A (see Fig. 1) Japanese Patent Laid-Open No. 05-138069 (Refer to Fig. 2) Japanese Utility Model Publication No. 2-133439 Gazette (See Fig. 1)

However, the conventional filtration type dust collector using static electricity improves the dust collection performance by directly applying the charge to the target powder. In the example of Patent Document 1, the charge of the powder due to the electrical resistivity is measured. There is a disadvantage that the effect is affected by the holding capacity and the electrostatic effect is reduced by the filtration pressure if the filtration speed is increased. In the example of Patent Document 2, the collecting part is a filter and a metal sintered body. However, there is a drawback in that there is a concern about performance deterioration due to fouling due to the use of the metal sintered body itself into which the complex structure having two steps and the powder are introduced for the high-voltage side electrode.
Note that Patent Document 3 constitutes a discharge electrode and a counter electrode for ion generation in a clean space after filtration, and does not have a function of improving performance as a dust collector.

The present invention has been made as a solution to such problems, and a DC high-voltage charging unit that forms an electrostatic field having an electric field strength equal to or higher than the corona discharge starting voltage is arranged on the clean space side after filtration by a filtration filter. By forming an ionic wind toward the filter, a filtration type dust collector using static electricity that depresses the dust-containing airflow to the filtration surface side and performs dedusting is configured.
In addition, the collection effect by the ion wind and the electrostatic field appears by using a filtration filter of about 40 mesh, but in order to make the effect remarkable, the net is made of a fine conductive material with a gap of 60 mesh (gap 0.28 mm) or more. Is preferably used as a filtration filter.

The following effects can be realized by the present invention.
Effective dust collection can be realized even with a filter with a large gap due to the powder pressing effect.
A filtration filter with a large gap can be applied, so that the filtration pressure loss can be kept low.
Since the electric field is formed from the clean space side after the filtration, the electrostatic effect is not reduced by the filtration pressure, and the filtration speed can be increased.
The electrostatic collection ability can be maintained by supplying stable electrification from the clean surface side to the filter material regardless of the contamination of the filter material filtration surface.
With the above effects, it is possible to realize a filtration type dust collector using static electricity that can be used at a low filtration pressure loss and a high filtration rate.

Next, embodiments of the present invention will be described with reference to the drawings as examples.
FIG. 1 is a side view showing the apparatus of the present invention, and FIG. 2 is a plan view thereof.
For the filter 1, a net made of a conductive material having a mesh size of 60 mesh (gap 0.28 mm) or more is used, and a discharge electrode 2 and a DC high voltage charging device 8 capable of obtaining an electric field strength higher than the corona discharge starting voltage are arranged. When the electrode 2 is made of 4 mm square steel, which is generally used in an electrostatic precipitator, etc., the direct current high voltage charging device 8 capable of obtaining an electric field strength of approximately 2 Kv / cm or more is used.
The polarity of the DC high-voltage charging device may be either positive or negative. For example, when ozone generation is to be avoided, the polarity is selected according to the purpose of use such as positive polarity.

Fig. 3 shows a case where a 60 mesh (0.28 mm gap) stainless steel wire mesh is configured as a filtration filter in a cylindrical shape, a 4 mm square steel discharge electrode is placed in the center, and positive DC high voltage charging is performed at a filtration rate of 1.5 m / min. An example of measurement of the relationship between the electric field strength and filtration pressure loss is shown.
It can be seen that effective dust collection is taking place due to a significant increase in differential pressure from around 2 Kv / cm in electric field strength under low filtration pressure loss.

Is a side view of the present invention Is a plan view of the present invention Is an example of filtration filter pressure loss measurement according to the present invention.

Explanation of symbols

1 is a filtration filter
2 is the discharge electrode
3 is the electric field formed between the discharge electrode and the filter and the ion wind.
4 is powder collecting surface
5 is a dust-containing air flow path
6 is clean side space
7 is Choshi
8 is a high voltage charging device

Claims (1)

On the clean space side after filtration by the filtration filter , a DC high-voltage charging part with an electric field strength equal to or higher than the corona discharge starting voltage with this filtration filter part as a counter electrode is arranged, and an ionic wind directed from the clean space side to the filtration filter surface Filtering type dust collector using static electricity, characterized by generating water.

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