JPH0947683A - Electric dust collector - Google Patents

Abstract

(57) [Summary] [Structure] The gas introduced from the gas inlet causes gas-phase ionic molecule reaction with the ions generated from the ion source in the gas reaction chamber. The gas released from the gas reaction chamber is introduced into a dust collection chamber where charged particles are removed from the gas. The cleaned gas is discharged to the outside from the gas outlet. A gas supply unit and a liquid supply unit respectively supply a gas and a liquid required for ion generation to an ion source that generates ions. In the dust collecting chamber, a voltage generated from a power source is applied to the electrodes to remove charged particles in the gas from the gas by Coulomb force. [Effect] A humidifying effect can be provided, and a substance that is not ionized in the gas phase ion molecule reaction can be dissolved in the droplets generated by spraying and collected.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a dust collector.

[0002]

2. Description of the Related Art Electrostatic Handbook (edited by The Institute of Static Electricity, Ohmsha, 1981), paragraphs 472 to 559,
There is a description of all electric dust collectors. Electric discharge is used to generate ions, and contaminants and dust are removed in the dust collection chamber.

[0003]

In the above-mentioned conventional technique, since electrical noise is generated due to the occurrence of discharge, a communication device used near and an electronic device vulnerable to noise may malfunction. Further, in the above-mentioned conventional technique, since discharge is used for ion generation, harmful substances such as ozone and nitric oxide are mixed in the gas discharged from the gas outlet.

An object of the present invention is to provide a safe electrostatic precipitator which does not generate electrical noise or harmful substances.

[0005]

The above problems result from the use of discharge in ion production. The present invention uses a sonic spray-on method to generate ions in order to realize a safe dust collector that does not adversely affect electronic devices and the human body.

[0006]

[Function] The sonic spray-on method is described in Analytical Chemistry 60 (1994) Item 4557 to Item 45.
Item 59 (Analitical Chemistry 60 (1994) pp4557-4559)
As described in, it is possible to generate ions without using discharge or high voltage. That is, ions or charged droplets are generated by spraying the liquid introduced into the capillary with a gas flow at a speed of sound.

[0007]

1 is a block diagram of an electrostatic precipitator according to an embodiment of the present invention. The gas introduced from the gas inlet causes a gas phase ion molecule reaction with the ions generated from the ion source in the gas reaction chamber. The gas released from the gas reaction chamber is introduced into a dust collection chamber where charged particles are removed from the gas. The cleaned gas is discharged to the outside from the gas outlet. A gas supply unit and a liquid supply unit respectively supply a gas and a liquid required for ion generation to an ion source that generates ions. In the dust collecting chamber, a voltage generated from a power source is applied to the electrodes to remove charged particles in the gas from the gas by Coulomb force.

FIG. 2 shows a sectional view of an electrostatic precipitator according to an embodiment of the present invention. The gas is introduced into the gas reaction chamber 3 from the gas inlet 1 by the fan 2. Ions and charged droplets generated in the ion source 4 are mixed with the gas introduced from the outside in the gas reaction chamber, and the pollutants and dust in the gas are chemically ionized by the gas phase ion molecule reaction. The dust collecting chamber is composed of a cylindrical electrode 5 and a cylindrical electrode 6. The gap between the electrodes is usually about 1 to 3 cm, and the length of the electrodes 5 and 6 is required to be 10 cm or more, but about 20 cm is sufficient. The potential of the electrode 5 is normally grounded, and the potential of the electrode 6 is 500 to 10000V.
About. It is also possible to reverse the polarity of the applied voltage. When a potential difference of 2000 V or more is applied between the electrodes, corona discharge may occur. The gas cleaned by passing between the electrodes 5 and 6 passes through the filter 7 and is discharged to the outside from the gas outlet 8.

The structure of the electrodes does not have to be cylindrical, and a combination of metal flat plates may be used. On the surface of the electrode 5 or 6, contaminants and dust are accumulated in layers. As the thickness of this dust increases, the dust collection effect decreases. In that case, a mechanical shock is given to the surface of the electrode 5 or 6, and the sediment is dropped and removed.

FIG. 3 is a sectional view of a sonic spray-on ion source for an electrostatic precipitator according to an embodiment of the present invention. The atomizing gas introduced into the ion source body 9 from above is discharged to the outside through the orifice 10 (diameter 0.4 mm). The capillary 11 is made of quartz and has an inner diameter of 0.1 mm and an outer diameter of 0.2 mm, and is fixed to the ion source body 9 by a supporting metal capillary 12. The central axes of the capillary 11 and the orifice 10 coincide with each other, and the tip of the capillary 11 projects from the orifice 10 by about 0.2 mm. The liquid is supplied from the liquid tank 13 to the capillary 11. In the sonic spray-on method, the amount of ions generated is maximum when the flow velocity of the spray gas near the end of the capillary 11 is about the speed of sound. When the gas flow velocity is about the speed of sound, the capillary 1
Since the atmospheric pressure at the end of 1 is a negative pressure, liquid is supplied from the liquid tank 13 to the capillary 11 without using a pump as shown in the figure. The liquid flow rate in this case is about 5 μl
/ Min, and will consume 200 ml of liquid in about one month. It is also possible to increase the liquid flow rate by using a pump for supplying the liquid.

The flow velocity of the spray gas near the end of the capillary 11 is such that the amount of ions produced is maximum when Mach 1 (sonic velocity), but the amount of ions is within the range of 0.8 to 1.2 Mach number. Can be neglected. Also, the orifice 1
When the thickness of 0 is sufficiently thin, the flow velocity of the atomizing gas will be Mach 1 when the pressure inside the ion source body 9 is set to about 1.9 atm.
(Sound velocity) is known. In reality, if the thickness of the orifice 10 is around 1 mm, the pressure drops, so
Atmospheric pressure is required. On the contrary, it is possible to control the flow velocity of the atomizing gas with a pressure gauge. Further, as described in the above-mentioned document Analytical Chemistry 60 (1994), the flow velocity of the spray gas is also determined by the gas flow rate F and the minimum value S of the area of the gap between the orifice 10 and the capillary 11, / S is 200m / s ~ 120
Ions are stably generated in the range of 0 m / s, but especially F
Ion generation efficiency is high when / S is in the range of 400 m / s to 800 m / s. Therefore, it is also possible to control the flow rate of the spray gas with a gas flow rate controller such as a mass flow meter or a purge meter.

[0012]

According to the electrostatic precipitator of the present invention, a liquid is sprayed inside. Therefore, when water is used as the liquid, not only dust collection of gas but also humidification effect can be obtained. Also, by mixing an appropriate solvent into the liquid, a substance that is not ionized in the gas phase ion molecule reaction can be dissolved and collected in the droplets generated by spraying.

[Brief description of drawings]

FIG. 1 is a block diagram of an electrostatic precipitator according to an embodiment of the present invention.

FIG. 2 is a sectional view of an electrostatic precipitator according to an embodiment of the present invention.

FIG. 3 is a schematic diagram showing a sonic sensor of an electrostatic precipitator according to an embodiment of the present invention.
Sectional drawing of a spray-on method ion source.

[Explanation of symbols]

1 ... Gas inlet, 2 ... Fan, 3 ... Gas reaction chamber, 4 ... Ion source, 5, 6 ... Electrode, 7 ... Filter, 8 ... Gas outlet,
9 ... Ion source body, 10 ... Orifice, 11 ... Capillary, 12 ... Supporting metal capillary, 13 ... Liquid tank.

Claims (10)

[Claims] 1. A gas inlet for introducing a gas, an ion source for generating ions, a gas reaction chamber for reacting the gas with the ions, and a voltage generated by a power source for removing charged particles and the like from the gas. In an electrostatic precipitator including a dust collection chamber and a gas outlet for discharging gas, ions are generated by atomizing the liquid supplied from the liquid supply unit by the ion source with the gas supplied from the gas supply unit. An electrostatic precipitator characterized by: 2. A capillary for allowing the ion source to spray a liquid, and an orifice into which the tip of the capillary is inserted, wherein the gas flows along the outer peripheral wall surface of the capillary to the tip of the orifice. And F is the flow rate in terms of the standard state of gas, and S is the area of the space in the space between the capillary and the orifice where the gas flows, which has the smallest area in a cross section perpendicular to the central axis of the capillary. The electrostatic precipitator according to claim 1, wherein the value determined by F / S is in the range of 200 m / s to 1200 m / s. 3. A capillary for spraying a liquid by the ion source, and an orifice into which the tip of the capillary is inserted, wherein the gas flows along the outer peripheral wall surface of the capillary to the tip of the orifice. And F is the flow rate in terms of the standard state of gas, and S is the area of the space in the space between the capillary and the orifice where the gas flows, which has the smallest area in a cross section perpendicular to the central axis of the capillary. The electrostatic precipitator according to claim 1, wherein the value determined by F / S is in the range of 400 m / s to 800 m / s. 4. The electrostatic precipitator according to claim 1, wherein the Mach number of the gas flow near the tip of the capillary is in the range of 0.3 to 3. 5. The electrostatic precipitator according to claim 1, wherein the Mach number of the gas flow near the tip of the capillary is in the range of 0.8 to 1.2. 6. The electrostatic precipitator according to claim 1, 2, 3, 4, or 5, wherein a plurality of the ion sources are installed. 7. The electrostatic precipitator according to claim 1, 2, 3, 4, 5 or 6, wherein the flow rate F of the gas supplied from the gas supply section to the ion source is controlled by a gas flow rate controller or the like. apparatus. 8. The electricity according to claim 1, 2, 3, 4, 5 or 6, wherein the pressure of the gas supplied from the gas supply unit to the ion source is controlled within the range of 1.9 to 4 atmospheres. Dust collector. 9. The electrostatic precipitator according to claim 7, wherein the gas supply unit comprises a compressor or a gas cylinder. 10. The electrostatic precipitator according to claim 9, wherein the gas supplied from the gas supply unit to the ion source is air, nitrogen, oxygen or the like.