JPH02119954A - Dielectric particle-packed bed filter device - Google Patents

Abstract

PURPOSE:To generate a stable partial electric discharge in a dielectric-particle bed by placing the bed of particles having smaller diameter at the inlet side or outlet side of a gas current, and placing the bed of particles having larger diameter at the middle of the gas current to form the dielectric-particle bed. CONSTITUTION:A discharge electrode 12 for charging the dust and bacteria contained in a gas is provided on the inlet side of a gas current, dielectric particles are packed on the downstream side of the gas current, a voltage is impressed on the dielectric-particle bed to collect dust and bacteria, and a partial electric discharge is generated in the dielectric-particle bed to sterilize the collected bacteria. In this case, the bed 16 of the particles having smaller diameter is placed on the inlet side or outlet side of the gas current, and the bed 18 of the particles having larger diameter is placed at the middle of the gas current to form the dielectric-particle bed. As a result, a partial electric discharge is stably generated in the dielectric-particle bed, and the collection rate of dust and bacteria and the sterilization rate are increased.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a dielectric particle filling station filter device, and in particular has a charging section on the gas flow inlet side that charges dust and bacteria contained in the gas. The downstream side of the gas flow is filled with dielectric particles, and a voltage is applied to the dielectric particle layer to collect dust and bacteria, as well as by causing partial discharge within the dielectric particle layer. This invention relates to a dielectric particle packed bed filter device that kills bacteria.

[Conventional technology]

The dielectric particle layer portion of the conventional dielectric particle packed layer filter device of this type is made by laminating dielectric particles having a diameter of about 2 +++ m as a layer with a thickness of about 20 layers. The wire mesh electrodes are configured to cause partial discharge within the particle layer and to apply a high voltage within a range that does not cause a short circuit between the wire mesh electrodes.

[Problem that the invention seeks to solve]

However, in the conventional technology as described above, when a high voltage is applied to the wire mesh electrode, the electric field strength (V/cm
) is strong at both ends of the dielectric filling layer, decreases toward the middle of the dielectric filling layer, and becomes approximately constant in most of the middle. Furthermore, the applied voltage must be higher than the voltage that causes partial discharge within the dielectric filling layer and must be lower than the short-circuit voltage between the wire mesh electrodes. Therefore, the partial discharge is strong in the portion of the dielectric particle layer near the wire mesh electrode, and the partial discharge does not occur widely up to the middle portion of the particle layer. In addition, the difference between the partial discharge inception voltage within the particle layer and the short-circuit voltage between the gold wJ electrodes becomes small, resulting in a drawback that the voltage range in which dust can be stably collected and sterilized is narrow.

The present invention has been made in view of the above circumstances, and provides a dielectric particle-filled layer filter device in which partial discharge occurs stably within the dielectric particle layer and has a high dust and bacteria collection rate and sterilization rate. The purpose is to

[Means for solving problems]

The present invention focuses on the fact that the partial discharge inception voltage of a dielectric particle layer decreases as the particle size of the dielectric particles increases, and the present invention stacks dielectric particles of different particle sizes on a dielectric particle along a gas flow. The problem of the conventional technology can be solved by arranging a particle layer with a small particle size on at least one of the gas inlet side or the outlet side, and a particle layer with a large particle size in the middle of the dielectric particle layer. This is to solve the problem.

[Effect]

According to the present invention, in a dielectric particle-filled filter device, the distribution of electric field intensity generated by partial discharge is changed by using dielectrics having different particle sizes in the particle layer. That is, a particle layer with a small particle size is provided at least on one of both ends of the particle layer where the electric field strength increases (inlet side and outlet side of the gas flow), and a particle layer containing particles with a large particle size is placed in the middle of the gas flow. The particle layers are stacked so that partial discharge occurs even in the middle part of the particle layer, and a large amount of ionized ions and ozone are generated to enhance the sterilizing effect.

〔Example〕

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

The arrow IO on the right side of Figure 1 indicates air containing dust and bacteria (
26 is the outer cylinder of the filter, which has a dielectric particle layer 16.18, 16 is a particle layer with a small particle size, and 18 is a particle layer with a large particle size. and
Two layers are stacked along the gas flow. This particle layer 16
And 1 gold on both sides of 18! Electrodes 20 and 22 are installed, and an AC high voltage electric current #+24 is connected to this gold wJ electrode. Further, a discharge electrode 12 for charging dust, bacteria, etc. is installed in front of this dielectric particle layer 16, 18,
A DC high voltage power source 14 is connected between the discharge electrode 12 and the wire mesh electrode 20. Further, the wire mesh electrode 20 is grounded. A fan 28 is also installed at the outlet of the filter to guide the gas out of the device.

In the above configuration, the gas containing dust and bacteria is
When entering the filter from this direction, the dust and bacteria in the air are charged positively or negatively by the corona discharge of the discharge electrode 12, and are taken into the dielectric particle layer 16.18.

In addition, the electric field strength within the dielectric particles 16.18 is concentrated in the small space between adjacent particles, so a strong electric field is obtained, and in that small space there is a discharge due to local air ionization ( Due to the high concentration of ions and ozone, the bacteria in the gas trapped in the particles 116.18 are captured on the dielectric material and destroyed, and the purified gas is transferred to the fan 28. Go out through the exit.

In order to destroy bacteria and the like in the air in this way, it is necessary to cause partial discharge in the particle layers 16 and 18. The principle will be explained below.

The graph in Figure 2 shows the particle size d+ d2, dz (d+
>62 >dj ) applied electric field strength (k V/c
m) and the current density flowing through the particle layer (m A / ct
) is a diagram experimentally showing the relationship between The current density is
If the amount of partial discharge occurring between particles increases, it will increase proportionally. Therefore, if current flows through the dielectric particle layer, it is considered that partial discharge is occurring. In addition, in the same figure, the particle diameter d1d, , d, is d+
>dz >dz, and the corresponding partial discharge initiation electric field strengths E, , E2, E, are E l< E 2
< E s, so the particle layer with larger particle size is
The experimental results clearly show that the partial discharge initiation electric field strength is lower than that of a particle layer with a small particle size.

Therefore, when two layers, the particle layer 16 with a small particle size and the particle layer 18 with a large particle size, are laminated in the air flow direction as in this embodiment, the partial discharge inception electric field strength in the particle layer changes in the air flow direction. The distribution becomes E, , El shown by the dotted line in FIG. 3, and the electric field strength that causes partial discharge can be lowered at the center of the dielectric particle layer. Also, the breaking points of dotted lines E and -E are
It corresponds to the boundary between particle layers of small and large particle sizes.

In FIG. 3, the horizontal axis is the distance from the ground wire mesh electrode, and the vertical axis is the electric field strength (K V /cm ). Eo is the electric field strength distribution in the air flow direction when a certain voltage is applied to the particle layer. Therefore, from this figure, the applied electric field strength E0, the partial discharge initiation electric field strength E for particles with a small particle size, and the partial discharge initiation electric field strength E+ for particles with a large particle size are Eo
>E3 and Eo >El, the electric field strength at that portion is stronger than the partial discharge inception voltage, which means that a partial discharge is occurring.

That is, the Dl 0 section in FIG. 3 is E. <E, so
Partial discharge is absent or weak. Moreover, partial discharge occurs in the pond part of the particle layer. On the other hand, the partial discharge initiation electric field strength for only one type of particle size is constant everywhere at E2 in FIG. Therefore, the applied electric field strength E. Partial discharge does not occur in the section D2 where the partial discharge initiation electric field strength E2 of the particles satisfies EO<E2, and it is better to combine dielectric particles of two types of particle sizes, since the partial discharge can be spread widely in the middle part of the particle layer. A discharge is occurring.

Furthermore, in the section Dl in FIG. 3, partial discharge does not occur or is weak, so insulation is provided in that section, and the risk of short-circuiting of the entire dielectric particle layer due to arc discharge can also be reduced.

As is clear from FIG. 3, the applied electric field strength E.

can be made higher than in the case of a single type of particle layer while ensuring the insulating portion and partial discharge generation site in the particle layer. This is because the partial discharge starting electric field strength E of a particle layer with a small particle size can be made larger than the partial discharge starting electric field strength E2 of one type of conventional particle layer with an intermediate size.

In the embodiment described above, a layer of particles having a small particle diameter was formed on the air inlet side, but the present invention is not limited thereto, and the effects of the present invention can be obtained even if the particle layer is laminated on at least one of the inlet side and the outlet side. Furthermore, a mixed layer of large and small particles may be provided in the boundary layer of each layer.

In addition, in Fig. 3, the partial discharge initiation electric field strength E of the particle layer with a small particle size is higher than the partial discharge initiation electric field intensity E2 of the particle layer with an intermediate size, so the current density flowing through that particle layer is small. Therefore, it is possible to save power consumption.

In the above embodiment, an alternating current voltage was applied to the dielectric particle layer, but a direct current may also be applied.

〔Effect of the invention〕

According to the dielectric particle charged layer filter device according to the present invention,
By stacking dielectric particles with different particle sizes, it is possible to prevent the entire particle layer from short-circuiting due to arc discharge, maintain a strong electric field within the dielectric, and secure a wide air ionization area. It collects and sterilizes dust and bacteria with high efficiency, and also provides energy-saving effects.

[Brief explanation of the drawing]

FIG. 1 is an axial cross-sectional view of a dielectric particle packed bed filter device according to an embodiment of the present invention, and FIG. 2 is a graph showing the relationship between the voltage applied to a particle layer of a certain particle size and the density of the current flowing therein. , Figure 3 shows the distance from the earth side wire mesh electrode and the electric field strength (
KV/c, ) and the partial discharge inception voltage E, ,
2 is a graph showing the distribution of the applied electric field strength Eo when dielectric particles of one type of particle size are used. IO...Arrow indicating gas flow, 12...Discharge electrode, 14...DC high voltage power supply, 16...Dielectric particle layer (small particle size), 18...Dielectric particle layer (particle size) large diameter),
20.22...Wire mesh electrode, 24...AC high voltage power supply, 28...Fan, 26...Outer cylinder.

Claims (1)

[Claims] (1) A charging part is provided on the inlet side of the gas flow to charge dust and bacteria contained in the gas, dielectric particles are filled in the downstream side of the gas flow, and a voltage is applied to the dielectric particle layer. In a dielectric particle packed bed filter device that collects dust and bacteria and kills the collected bacteria by causing partial discharge within the dielectric particle layer, at least one of the inlet side and the outlet side of the gas flow is used. A dielectric particle packed bed filter device characterized in that the dielectric particle layer is constructed by laminating a particle layer having a small particle size and a particle layer containing particles having a large particle size in the middle of a gas flow.