JPH09173897A - Particle collection apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the collection efficiency of fine particles at a time of use under low voltage. SOLUTION: A detachable filter cassette 3 is inserted into piping 1 having a fan 2 arranged to one end thereof. A plurality of charging extremely fine metal wire filters 4, plastic meshes 5 and collecting extremely fine metal wire filters 6 are arranged in the filter cassette 3 at a right angle to air streams. The charging filters 4 and the collecting filters 6 are alternately arranged to be electrically connected to the positive and negative poles of a DC power supply 7 generating DC voltage of about 12V. The plastic meshes 5 are arranged between the charging filters 4 and the collecting filters 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a particle collector for collecting fine particles such as dust in the air.

[0002]

2. Description of the Related Art Conventionally, as a device for collecting dust, there has been a device for collecting dust in the air by using a corona discharge as shown in FIG. This device was connected to a corona discharge part in which a negative electrode rod 9 connected to a high-voltage power supply 8 and a positive discharge electrode 10 were arranged on the upstream side of an air flow generated by a fan, and a DC power supply 11 on the downstream side. The positive electrode 12 and the dust collecting electrode plate 13 are composed of a plurality of particles arranged in parallel.

In this particle collecting apparatus, a voltage of several kV is applied to the negative electrode rod 9 and the normal discharge electrode 10 to cause corona discharge to charge the dust, and the dust is collected by the dust collecting electrode plate 13. is there. In addition, as an example in which discharge is not used, "Japanese Patent Laid-Open No. 6-1
No. 42549 ”, a mesh member for charging particles is arranged on the upstream side, and a mesh member for adsorption is arranged on the downstream side. A DC voltage of 12 to 1250 V is applied to these members, and the mesh member for charging particles is used. There is also one in which the fine particles are charged and the fine particles charged by the adsorption mesh member are collected by the Coulomb force.

[0004]

However, in the conventional collecting device using the corona discharge, since the particles are directly discharged, there is a possibility that a fire may occur, the particles may have a burnt odor, or the discharge noise such as crackling due to the discharge may cause a noise. There was a problem that it occurred. In addition, there is a problem that ozone is generated due to the discharge action and smells of ozone. Further, since a high voltage of several kV is required to cause corona discharge, there is a problem that the device becomes large.

However, the above-mentioned "JP-A-6-14254" is also used.
When used at a low voltage in the configuration of "No.
There is a problem that the collection efficiency is poor because there are many uncharged fine particles. An object of the present invention is to provide a particle collecting apparatus capable of collecting particles at a low voltage without causing discharge and improving efficiency.

[0006]

The particle collecting apparatus of the present invention comprises a plurality of mesh filters made of ultrafine metal wires installed in an air flow containing fine particles, and a DC low voltage is alternately applied to the mesh filters as positive electrodes, It is applied so as to be a negative electrode, and a plastic mesh is placed between the mesh filters.

In the particle collecting apparatus of the present invention, the particles in the air stream are charged by the mesh filter to which a voltage is applied and which is installed in the upstream portion, and a voltage having a sign different from that of the upstream portion in the downstream portion is applied. It is collected by the Coulomb force in the mesh filter. Then, the fine particles that are not charged by the metal mesh in the upstream portion are collected by the dielectric polarization force acting between the fine particles and the plastic polarized by the external electric field. Further, the fine particles that collide with the mesh filter and the plastic mesh are collected by the adsorbing force, but since the plastic has a large adsorbing force, the fine particles are easily collected.

Further, since the mesh filter is an ultrafine metal wire, it is possible to suppress an increase in pressure loss. Further, since the surface area of the mesh filter is increased and the probability that the particles come into contact with each other is increased, the particles are easily collected.
In addition, because it creates a more uniform electric field than thick metal wires,
The polarization of the plastic mesh becomes uniform. Further, the plastic mesh between the mesh filters prevents the mesh filters from coming into contact with each other and a short circuit due to the bridge of the collected fine particles.

[0009]

FIG. 1 is a schematic diagram showing the structure of a particle collecting apparatus according to an embodiment of the present invention. Reference numeral 1 is a pipe made of an insulator, and air containing fine particles d flows in the pipe 1 by an air flow created by a blower fan 2.
A detachable filter cassette 3 is inserted in the pipe 1. In the filter cassette 3, a plurality of charging ultrafine metal wire filters 4, a plastic mesh 5, and a collecting ultrafine metal wire filter 6 are installed so as to be perpendicular to the air flow. The charging filter 4 and the collecting filter 6 are alternately arranged, and are electrically connected to the positive electrode and the negative electrode of the DC power supply 7 that generates a DC voltage of about 12V, respectively. The plastic mesh 5 is the charging filter 4
And the collection filter 6 are installed.

Charging filter 4 and collecting filter 6
Is an ultrafine metal wire with a wire diameter of 0.01 to 0.1 mm
I am using a knitted piece of 00 mesh. The plastic mesh 5 is made by knitting an ultrafine fiber such as nylon or polyethylene into a mesh of several tens of mesh.

In the particle collecting apparatus of this embodiment, the fine particles d are collected by the collecting filter 6 and the plastic mesh 5. First, the collection of the collection filter will be described. When the blower fan 2 rotates, air containing fine particles d such as dust flows through the pipe 1. Then, when the fine particles d pass through the charging filter 4 connected to the positive electrode of the DC power source,
It is charged to a positive charge. Then, the collection filter 6 in which the fine particles charged to a positive charge are connected to the negative electrode of the DC power supply
When passing through the portion, the fine particles are collected by the collecting filter 6 by the Coulomb force. Further, the fine particles d not collected are collected by the next collection filter 6.

Next, the collection of the plastic mesh 5 will be described. The plastic mesh 5 makes it possible to collect uncharged fine particles that are not charged by the charging filter 4. 2A and 2B are views for explaining the effect of the plastic mesh of the particle collecting apparatus of the present invention, FIG. 2A is a view of a part of the apparatus as seen from the side, and FIG. 3d and the plastic mesh 5 are viewed from above. The plastic mesh 5 is a charging filter 4 to which a voltage is applied.
And is polarized by the electric field formed by the collection filter 6. Then, the dielectric polarization force acts between the uncharged fine particles d and the polarized plastic mesh 5, and the fine particles d
Are collected on the plastic mesh 5.

When the fine particles d collide with the metal filters 4 and 6 or the plastic mesh 5, they adhere to and are collected by the adsorbing force. Experimental results using the above particle collection system will be described. The collection rate η of the device according to the present embodiment is obtained by measuring the number of fine particles d before and after the filter cassette 3 with a particle counter, and η = (number of particles after filtering) / (number of particles before filtering)
It was set to × 100 [%].

Next, the collection rate and pressure loss of the particle collecting apparatus of this embodiment will be shown. Here, one charging filter and one collecting filter are set as one set. FIG. 3 shows the results of measuring the collection rate depending on the number of filters. The metal wire filters 4 and 6 are made of stainless steel with a wire diameter of 0.05 mm woven into 150 mesh, and the plastic mesh 5
Used two types of nylon or polyethylene woven into 10 mesh. In FIG. 3, A is a case where the plastic mesh 5 is not inserted, B is a case where the plastic mesh 5 made of polyethylene and C is a case where the plastic mesh 5 made of nylon is used. The same reference numerals are used in the following drawings.

According to FIG. 3, when the plastic mesh 5 is inserted between the metal meshes 4 and 6, the collection rate is improved as compared with the case where it is not inserted. Especially the metal mesh is 1
In the case of the set, the collection rate is more than doubled when the plastic mesh is added. This means that when the number of sets of the metal filters 4 and 6 is one, the number of the charging filters 4 is only one, and therefore the uncharged fine particles d are increased. It clearly shows that the particles d which have not been collected are collected by the plastic mesh 5.

FIG. 4 shows the pressure loss during the above experiment. The pressure loss is almost proportional to the number of sets of the metal wire filters 4 and 6, and increases when the plastic mesh 5 is installed, but both values are at a level where there is no problem in actual use.

FIG. 5 shows a metal wire having a diameter of 0.05 mm as 100,
Metal wire filter molded with 150, 200 mesh 4,
The collection rate of the particle collection device when two sets of 6 are installed is shown.
The reference numerals in the figure are the same as those in FIG. 3, and the description thereof will be omitted. As shown in FIG. 5, the finer the mesh of the filters 4 and 6, the higher the collection rate, but as shown in FIG. 6, the pressure loss tends to increase at the same time. However, there is no problem in actual use.

When this device is used for a long time, the filter 4,
6 and the fine particles collected on the plastic mesh 5 clog and the collection rate deteriorates, but it is remarkable even if the filter cassette 3 used in the experiment is washed with water containing a detergent, dried and then used in the experiment again. There was no deterioration in performance, and it could be used repeatedly.

[0019]

According to the particle collecting apparatus of the present invention, by placing a plastic mesh between mesh filters made of ultrafine metal wires to which a low voltage is applied, uncharged particles can be removed from the plastic mesh by a plastic mesh. The collection efficiency can be improved because it can be collected.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of a particle collection device according to an embodiment of the present invention.

FIG. 2 is a view for explaining the effect of the plastic mesh of the particle collecting apparatus of the present invention.

FIG. 3 is a diagram showing a graph of a collection rate when the number of filters is changed.

FIG. 4 is a diagram showing a graph of pressure loss when the number of filters is changed.

FIG. 5 is a diagram showing a graph of a collection rate when filters having different mesh numbers are used.

FIG. 6 is a diagram showing a graph of pressure loss when filters having different mesh numbers are used.

FIG. 7 is a schematic diagram showing a configuration of a conventional electrostatic precipitator.

[Explanation of symbols]

 1 Piping 2 Fan for Fan 3 Filter Cassette 4 Micro Metal Wire Filter (Mesh Filter) for Charging 5 Plastic Mesh 6 Micro Metal Wire Filter (Mesh Filter) for Collection 7 DC Power Supply 8 High Voltage Power Supply 9 Negative Electrode 10 Positive Discharge Electrode 11 DC Power supply 12 Positive electrode plate 13 Dust collecting electrode plate d Dust

Claims (2)

[Claims] 1. A particle collecting apparatus for collecting and removing fine particles floating in air, wherein a plurality of mesh filters made of fine metal wires are installed in an air flow containing fine particles, and a DC low voltage is applied to the mesh filter. A particle collecting device characterized in that a voltage is alternately applied so as to have a positive electrode and a negative electrode, and a plastic mesh is installed between the mesh filters. 2. The particle collecting apparatus according to claim 1, wherein the ultrafine metal wire of the mesh filter has a wire diameter of 0.01 to 0.1 mm and a mesh number of 50 to 200.