JPH0687994B2 - Charge type filter - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a charge-type filter, and more specifically, it forms an electric field by charging between a high-voltage electrode and a ground electrode or between an anode and a cathode to prevent dust and materials. The present invention relates to a charge-type filter which can be used in various fields of air cleaning and which has high performance and high performance due to electrostatic and / or dielectric action by charging and.

[Prior Art and Problems] In a conventional filter that collects dust by charging, the dust is charged by passing it through an electric field formed between a high-voltage electrode and a ground electrode, Dust is collected or coarsened by the ground electrode, and dust that is not collected by the ground electrode or dust that is re-scattered after being collected by the ground electrode is mechanically collected, for example, as shown in JP-A-56-37060. In addition to the dust charging section, a material made of a dielectric material is further installed between the high voltage electrode and the ground electrode to form an electric field, and the material is made to be dielectric and the dust is mechanically and electrostatically removed. There is a method of collecting, for example, a method shown in JP-A-58-92471, and the former is generally known as an electrostatic precipitator with material, and the latter is known as a dielectric filter device.

The former method has a drawback that it is inferior in dust collection efficiency, and in addition, it requires frequent cleaning of the installed electrodes and replacement of materials, and is also inferior in maintainability, while the latter method has a drawback. Although it has a higher collection efficiency than the former, it has a drawback that the material is heavily clogged due to the high efficiency of collecting dust, the collection capacity is small, and the material life is short.

[Object of the Invention] The present invention has been made to solve the above-mentioned drawbacks of the prior art, and provides a charge-type filter having excellent collection efficiency, long material life, and excellent workability and maintainability. With the goal.

[Structure of the Invention] The present invention is a charge-type filter formed by integrally forming a linear or strip-shaped conductive portion on a material surface to form an electrode, the electrode being perpendicular to the material surface. When seen from a different direction, the high voltage electrode and the installed electrode are
Alternatively, the anode and the cathode are alternately arranged, and the distance between the high-voltage electrode and the installation electrode, or the electrode between the anode and the cathode is 2 to 50 mm, and the material is a linear or band-shaped conductive portion and a fold line. The present invention relates to a charge-type filter which is fold-folded so that and intersect, and a dust charging portion is not provided upstream of the material.

The present invention will be described below with reference to the drawings.
A) of the figure is a plan view showing an example of a conductive part of the charge-type filter substrate of the present invention, and b) of FIGS. 1 to 3 is a sectional view thereof.

Further, FIG. 4 is an explanatory view showing a usage state of the charge type filter according to the present invention.

First, the material 1 used in the present invention will be described.
As the material 1, all known air conditioning materials can be used. These materials 1 are materials made of materials such as paper, non-woven fabric, or inorganic fiber, and have a low apparent density for coarse dust to a high density called HEPA filter for ultra-high performance. Anything can be used, but since a high voltage is used in the present invention, it is necessary to use an insulating material. It is also preferable to make the material flame-retardant in case of an emergency.

In particular, a non-woven fabric containing at least 50% or more of synthetic fibers such as polyester and polypropylene serves as a dielectric filter when charged, so that the dust collection efficiency is also high and it is considered to be optimal.

Further, providing a density gradient in the material or changing the fold shape can also be effectively utilized in the present invention in the conventional manner.

Next, the conductive portion 2 will be described. The conductive portion 2 can be arbitrarily selected as long as it can withstand high-voltage charging, but a structure that does not prevent the passage of airflow is desirable. Therefore, the conductive portion is 5 mm or less. It is suitable to be a linear body having a width of 5 mm, and when the width exceeds 5 mm, the excess area is reduced to increase the pressure loss and decrease the dust holding capacity, and further, it is inferior to the electric field formation, which is preferable. Absent. Further, the conductive portions 2 do not necessarily have to be straight lines, and may have, for example, a curved line as shown in FIG. 2, but in any case, adjacent conductive portions have a parallel relationship with each other (here, normal parallel Not only the relationship but also the distance between corresponding two points on the adjacent conductive parts is preferably the same at any point on the conductive part.

The conductive portion 2 of the present invention has a specific resistance of 10 ⁴ Ω on the surface of the material.
· Cm or less, preferably or those adhering to 10 ⁰ Omega · cm or less of the metal wire and the conductive linear body such as carbon fiber, silver, copper, an electrically conductive powder such as aluminum or carbon adhesive A material obtained by linearly applying a dispersed paste having a specific resistance of 10 ⁶ Ω · cm or less is preferably used. The one provided integrally with the material in this manner is preferable because it has high adhesion to the material, is easy to be processed such as pleating, and is excellent in workability and maintenance such as material replacement.

The conductive portion 2 is connected to a power source or the like and constitutes a circuit as an electrode. In the present invention, the high voltage electrode 2B means a conductive part connected to a high voltage power source, and the ground electrode 2A means a grounded conductive part. On the other hand, in the present invention, the anode means a conductive portion connected to the anode of the power source, and the cathode means a conductive portion connected to the cathode of the power source. In this case, both electrodes form a circuit in which a power source is connected.

In the present invention, the high-voltage electrodes and the ground electrodes, or the anodes and the cathodes are alternately arranged when seen from the direction perpendicular to the material surface. For example, as shown in FIGS. 1 and 2, when the electrodes are divided into a high voltage electrode on one surface and a ground electrode on the other surface and both surfaces, see through the material perpendicular to the surface. For example, the electrodes on both surfaces are projected on the same plane, but at this time, the high voltage electrodes and the ground electrodes are arranged alternately. When electrodes are formed only on one surface as shown in FIG. 3, adjacent electrodes are different electrodes, and high voltage electrodes and ground electrodes are alternately repeated.

By arranging the electrodes in this way, when viewed from a direction perpendicular to the material surface, the high voltage electrode and the ground electrode are less likely to be clogged and dust is collected compared to the case where the high voltage electrode and the ground electrode overlap each other. The capacity also increases. The reason for this is not clear, but when the high-voltage electrodes and the ground electrodes are arranged alternately, a strong gradient force (a force generated by the electric field gradient) is generated by the non-uniform electrolysis, and the dust is unevenly distributed inside the filter. As a result, dust accumulates in the filter in the state where a path for the air flow containing dust is secured, so the time until clogging becomes longer and more dust can be collected. Thought to be

In particular, when the high voltage electrode 2B is arranged on one surface and the ground electrode 2A is arranged on the other surface, it is possible to increase the distance between the high voltage electrode 2B and the ground electrode 2A, so that the electric field forming area is expanded. As a result, a uniform dust collecting action can be obtained, and a short circuit between the electrodes can be prevented.

Further, among the above-mentioned positional relations of the electrodes, it is particularly preferable that the ground electrode is arranged on the inflow side of the air flow and the high voltage electrode is arranged on the outflow side. By doing so, the electric field action and / or the dielectric action of the material are performed. As a result, the speed of the dust passing through the material is reduced, so that the dust collection efficiency is improved.

The distance between the high-voltage electrode 2B and the ground electrode 2A is considered to be 2 to 50 mm in order to prevent a short circuit and obtain a good electric field, and regarding the potential difference between the electrodes, 0.2 to 1.0 kv / mm (distance between electrodes), preferably 0.5 to
It is preferably 0.9 kv / mm.

The operation of the charge type filter of the present invention will be described below with reference to FIG. The charge type filter used in FIG. 4 is obtained by folding the filter shown in FIG. 1 so that the linear or band-shaped conductive portion on the material surface and the fold line intersect.

In the charge type filter of FIG. 4, an air flow containing dust flows from the surface of the ground electrode side to the high voltage electrode side in the material, and conversely, an electric field is formed from the high voltage electrode 2B to the ground electrode 2A. . The dust that has passed through the ground electrode is charged in the material and receives an electric attraction force to the ground electrode, which is opposite to the flow of the air flow. Therefore, the dust that has reached the material is decelerated by the influence of the ventilation resistance and electric field of the material and / or the dielectric action of the material, so that it is efficiently collected by the material. At this time,
Since the dust is charged to the same polarity, the dust does not agglomerate densely and is collected as if it were brushed, so even if dust accumulates, the material will not be clogged. . In addition, since the force of dust to be released from the material due to electrification is obviously smaller than the flow velocity of the air flow, the dust is not released from the material surface. Furthermore,
The direction of the electric field from the high-voltage electrode 2B to the ground electrode 2A is such that the high-voltage electrodes and the ground electrodes are arranged alternately when the electrode is seen through from a direction perpendicular to the material surface. It does not directly face the direction of the air flow, but intersects diagonally. Therefore, the distribution of the electric field spreads in the horizontal direction of the material, and an unequal electric field that is not a specific region as in the case where the electrodes face each other is formed, which is considered to be advantageous for improving the dust holding capacity.

As a result, dust is retained on the material for a while, but since all the dust does not aggregate densely due to the action of the electric field, clogging is less likely to occur and the pressure loss rises compared to conventional charged filters. Far less.

Note that the advantage of arranging the ground electrode on the air flow inflow side is that excessive accumulation of charged dust particles may cause dust release due to the repulsive action between the dust particles and a reduction in collection efficiency. Since this example is always grounded by the ground electrode, these obstacles due to charge accumulation do not occur.

Hereinafter, the charged filter of the present invention will be described more specifically by way of examples, but the present invention is not limited to these examples.

[Example 1] As a material, a basis weight of 100% of flame-retardant polyester fiber (1.5 denier, 44 mm long and 3 denier, 51 mm long) 150 g / m
^2, uses the combining of 3mm thick web with an adhesive of a polyvinyl chloride-based nonwoven, adhesive in parallel lines of the line spacing 12mm multifilament carbon fibers having a specific resistance 1.8Ω · cm to this surface , And then, as shown in FIG. 1 a), when viewed from the direction perpendicular to the material surface on the material back surface, the surface is arranged so as to be alternately arranged with the conductive parts on the surface. The same carbon fiber multifilaments were placed at the same intervals as above to form a conductive part, and a charge-type filter substrate according to the present invention was obtained.

This base material is folded and the conductive part on the air flow inflow side is grounded to serve as a ground electrode, and the conductive part on the outflow side is connected to a high-voltage power supply to form a high-voltage electrode, and the average potential difference between the electrodes is 0.8 kv / mm. After charging under the conditions, a test was conducted according to the test method of JIS D-1612, and when the pressure loss reached 100 mmAq, the dust retention capacity and the dust collection efficiency were measured.

As is clear from Table 1, the charge-type filter of the present invention is far superior in dust holding capacity and collection efficiency to those of the comparative example, and has an extremely good dust collecting action. It was the most suitable as an air cleaner for internal combustion engines.

[Comparative Example 1] For comparison with Example 1, the same non-woven fabric as in Example 1 was used as a material, and a wire mesh was used as a high voltage electrode and a ground electrode instead of the conductive portion made of carbon fiber according to the material shape. Then, a test piece was prepared, superposed on the overlayer, and tested under the same conditions as in Example 1.

The results are shown in Table 1. The dust retention capacity and the collection efficiency are inferior to those of the examples, and the clogging is apt to occur, and the life is extremely short.

[Example 2] As a material, the average fiber diameter was 2 µm, the basis weight was 60 g / m ² , and the thickness was 0.
On the surface of the material, a 5 mm polyolefin meltblown non-woven fabric and a dry process nonwoven fabric with an average denier of 2 denier consisting of bolicral fiber and modacrylic fiber of 120 g / m ² and 1.1 mm thickness were laminated. In contrast, the specific resistance after drying and solidification is 10 so that the conductive parts on the front and back are arranged alternately when viewed from the direction perpendicular to it.
A conductive coating material of 2 Ω · cm was applied on the surface of each material in parallel lines having a width of 2 mm and a line interval of 16 mm to form a conductive part, and a charged filter substrate according to the present invention was obtained.

This product was also fold-processed, the airflow inflow side was used as a ground electrode, the outflow side was used as a high voltage electrode, and the average potential difference between the electrodes was charged under the conditions of 0.8 kv / mm, and then according to ASHRAE 52-76. Tested by the colorimetric method and the results are shown in Table 2. It shows excellent collection efficiency even for extremely fine dust and has a low pressure loss, which is useful as a high-performance filter. It was something.

[Comparative Example 2] The same material as that used in Example 2 was electrified by previously charging it with a high voltage, and then this was folded and uncharged to obtain an electret. A comparison was made.

The results are also shown in Table 2, and compared with those in Example 2,
The dust collection efficiency was the same, but the storage capacity was much worse.

[Advantages of the Invention] The charge filter according to the present invention does not require any special material or equipment because it can use the materials that have been conventionally used as it is, and also has a conductive property such as a metal wire to be a conductive part. A linear body or a paste in which a conductive powder such as silver or carbon is dispersed in an adhesive or the like can be obtained at low cost and easily, and there is no difficulty in the lamination work, so it is simple. Can be manufactured.

Further, the charge type filter of the present invention has a high voltage electrode and a ground electrode, or an anode and a cathode which are alternately arranged, when the electrode is seen from the direction perpendicular to the material surface as described above. Therefore, the dust holding capacity is far superior to the conventional one. This not only reduces the number of times the charge type filter needs to be replaced, but also enables extremely long-term use by performing dust removal work of a conventional level. Therefore, the maintenance and cost associated with the replacement of the charge type filter are reduced, and the cost is very excellent.

Furthermore, since the charge type filter of the present invention has a much lower increase in pressure loss than the conventional filter, when used as an air cleaner for an internal combustion engine or the like, intake efficiency or combustion efficiency is increased, so that fuel consumption is improved and output is improved. When used in the general field of air cleaning, it also enables the use of higher density materials and the treatment of a larger amount of airflow, providing an air cleaning device with a high performance and compact structure. can do.

Therefore, the charge-type filter of the present invention has not only a good dust collection efficiency, which is its original function, but also a high dust holding capacity and a long service life, which is excellent in economical efficiency and productivity, and has a usable range. Is a wide range of ideal charge filters.

[Brief description of drawings]

1 to 3 a) are plan views of the charge-type filter of the present invention, and FIGS. 1 to 3 b) are cross-sectional views thereof. FIG. 4 is an explanatory view showing a usage state of the charge type filter according to the present invention. The numbers in the figure are 1 ... material, 2 ... conductive part 2A ... ground electrode, 2B ... high voltage electrode

Claims (4)

[Claims] 1. A charge-type filter comprising an electrode formed by integrally forming a linear or strip-shaped conductive portion on the material surface, the electrode being transmitted from a direction perpendicular to the material surface. In this case, the high-voltage electrode and the ground electrode, or the anode and the cathode are arranged alternately, and the electrode distance between the high-voltage electrode and the ground electrode, or the anode and the cathode is 2 to 50 mm, and A charge-type filter characterized in that the material is fold-folded so that a linear or strip-shaped conductive portion and a fold line intersect with each other, and a dust charging portion is not provided upstream of the material. 2. A charge-type air filter according to claim 1, wherein electrodes are provided on both surfaces of the material. 3. The ground electrode is arranged on the inflow side of the air flow, and the high voltage electrode is arranged on the outflow side.
Charge type air filter according to the item. 4. A charge-type air filter according to claim 1, wherein the electrode is provided on either surface of the material.