JPH0215260B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an electrostatic dust removal device, and in particular, it does not cause short-circuit discharge due to high voltage, can efficiently collect fine dust, and can easily replace filters. This invention relates to a simple electrostatic dust removal device.

(Conventional technology) Due to the development of industry and urbanization, urban air pollution has increased, hindering productivity in industry and having a negative impact on the health and living environment of residential areas. It's coming. Therefore, while pollution prevention measures such as pollution source control are being considered and implemented, air purification of confined spaces has become an important issue in more advanced or broader fields. In particular, in the semiconductor industry, ultra-fine processing such as VLSI, and in the precision machinery industry, to improve the yield of ultra-precision products, as well as advanced biotechnology in operating rooms, sterile rooms, bacterial experiments, and food processing. In addition, air purifiers have become indispensable as environmental hygiene measures for homes, workplaces, recreational facilities, etc., including measures against dust, smoke, dust mites, and pollen. For this reason, the required performance of high-performance filters has been improved to a target suspended particle size of 0.3 μm or 0.1 μm or more, and the results are gradually being achieved.

Incidentally, the dust collection mechanisms of conventional air purifiers are roughly divided into mechanical dust collection systems and electrical dust collection systems in terms of operating principle. Generally speaking, mechanical dust collection methods have large particles that can be collected, and there are many difficulties in terms of equipment and handling.Today, electrical dust collection methods are generally used. .

Electrostatic precipitators that use this electric dust collection method include electrostatic precipitators that collect dust electrostatically after ionizing it by corona discharge, and electrostatic precipitators that collect dust electrostatically after ionizing it by corona discharge. There are electrostatic dielectric air purifiers that electrostatically collect air throughout the body.

First, regarding the former conventional electrostatic precipitator, the fourth
This will be explained with reference to the drawings and FIG.

In FIG. 4, to explain the principle of dust collection of this electrostatic precipitator, suspended particles contained in contaminated air 1 pass through a prefilter 2, and enter a charging section 3 having a discharge wire 4 that performs corona discharge (+ ), and the (+) charged particles are repelled by the high-voltage electrode plate 6 in the dust collecting section 5 and collected by the ground electrode plate 7. Therefore, purified air 8 in which suspended particles are collected can be obtained.

FIG. 5 is a sectional view showing an example of an electrostatic precipitator employing such a dust collection principle, in which a discharge wire 10 having a positive potential, a discharge electrode plate 11 having a positive potential, and a collector having a negative potential. It has a unit in which dust electrode plates 12 are assembled, and the holder part 13 has a front filter 14 on the front part and a rear filter 1 on the rear part.
5 and an activated carbon filter 16 for deodorizing are set. The set item is stored in the case body 17 through the grille 18 which serves as a suction port. A fan 19 and an air outlet 2 are provided at the rear of the case body 17.
0 is set.

Therefore, the suspended particles contained in the contaminated air sucked in from the suction port by the fan 19 pass through the front filter 14, and are charged to (+) by the discharge wire 10 performing corona discharge. The (+) charged particles are repelled by the discharge electrode plate 11 having a positive potential, and are collected by the collecting electrode plate 12 having a negative potential.
The purified air flow passes through a rear filter 15 and an activated carbon filter 16 and is blown out from an outlet 20.

Next, the latter conventional electrostatic dielectric air purifier has already been published as Japanese Patent Application Laid-Open No. 1956-1956 filed by the same inventor as the present application, and this is described in No. 6
This will be explained in detail with reference to FIGS. 8 through 8.

First, referring to FIG. 6, to explain the principle of dust collection, this electrostatic dielectric type air purifier has electrodes 31 and 32 disposed on a porous dielectric material 30, and a gap between the electrodes 31 and 32. A high DC voltage is applied to the porous dielectric material 30 to generate a strong electric field to collect floating particles attempting to pass through the vents in the dielectric material.

FIG. 7 is a sectional view of an electrostatic dielectric air purifier employing such a dust collection principle, and FIG. 8 is a configuration diagram of its filter element. In these figures, a filter element 41 is disposed in the center of a case 40, and air with inhaled contaminant particles is sucked into a fan 42 and sucked in through a suction port 43.
In order to prevent clogging of the filter element 41,
A filter bag 44 is provided to collect coarse dirt. As shown in FIG. 8a, the filter element 41 has a metal thin film 48 such as A1 on one side of a porous dielectric material 47 such as urethane foam, which serves as one electrode, and a metal thin film 48 serving as one electrode, such as A1, on the other side with the porous dielectric material 47 in between. As shown in FIG. 8b, a plurality of filter media on which a metal thin film 49 is formed is wound into a cylindrical shape, and a terminal 48 is connected between adjacent electrodes 48 and 49.
A high voltage is applied from a DC high voltage power supply 45 via a and 49a. 47a is a support net for the filter element 41.

Therefore, the suspended particles inhaled from the suction port 43 are physically captured in the ventilation holes of the filter material, and
A strong electrostatic field is generated by the dielectric disposed between the positive and negative electrodes to charge the airborne particles, and the charged airborne particles are trapped on the dielectric vent wall.

(Problems to be Solved by the Invention) However, the electrostatic precipitator shown in FIGS. 4 and 5 above has the following problems.

(1) Cleaning and maintenance are difficult.

If a large amount of dust adheres to the dust collection plate, the dust collection effect will decrease, so prepare a weak alkaline detergent dissolved in lukewarm water at about 60°C, remove the set dust collection unit from the grill 18, and clean it from the front filter 14. Then, the electrostatic precipitator from which the rear filter 15 and activated carbon filter 16 have been removed is immersed in the cleaning solution, and is usually immersed for about 3 hours, depending on the degree of contamination. Then, while soaking in the cleaning solution, shake it back and forth and from side to side to remove dirt. In this case, avoid touching the thin discharge wire 10.
In particular, if grass smoke or the like adheres to the dust collecting plate 12, it is difficult to remove the dirt, but care must be taken not to scrub the dust collecting plate with a brush or the like.

(2) Re-scattering of collected particles In order to improve the collection ability, it is necessary to increase the applied voltage or lengthen the voltage application section. Due to the concentration of the electric field in the upper part, a discharge occurs and the collected particles are scattered again.

(3) Easy to cause radio wave interference.

When corona discharge occurs, high-frequency current flows through the ionized space, which causes noise interference to radios.

(4) Ozone is generated.

Because corona discharge is involved, ozone is generated, which can irritate or attack mucous membranes.

Next, in the electrostatic dielectric air purifier shown in FIGS. 6 to 8 described above, (1) the filter element equipped with the strip-shaped electrode is disposable, and it cannot be improved from an economic point of view; mosquito.

(2) Is it possible to make the device more compact?

(3) Is it possible to improve it so that it is suitable for use under high temperature and high humidity conditions?

In order to meet these requirements, the present invention has developed an electrostatic dust remover that does not cause short-circuit discharge due to high voltage, can efficiently collect fine dust, has easy filter element replacement, and has low maintenance costs. The purpose is to provide equipment.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a first electrode to which a positive potential is applied, and a first electrode located at a position recessed from the tip of the first electrode. An electrode unit consisting of a second electrode to which a negative potential is applied which faces the end of the electrode with a solid insulator in between, a ventilation path formed outside the second electrode, and a ventilation path formed on the outside of the second electrode. A conductive filter element is installed in the passage and comes into contact with the second electrode, and forced ventilation means for venting the gas to be purified is provided in the ventilation passage.

(Function) According to the present invention, by adopting the above structure, a conductive electrode is electrically connected to the tip of the first electrode and the second electrode by the edge effect at the tip of the electrode unit. An electric field is generated between the tips of the filter elements, and under the action of the electric field, suspended particles are guided to the filter elements. There, while being physically captured by the conductive filter element, the charged airborne particles are attracted and captured by electrostatic induction to the filter element, which has a large surface area and is electrically connected to the second electrode. . Furthermore, the electrode unit is mechanically strong and electrically stable. Furthermore, when replacing the filter element, it is only necessary to insert it into the ventilation path, and the replacement can be easily performed.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view of an electrostatic dust remover according to the present invention, FIG. 2 is an exploded perspective view of the electrostatic dust remover shown in FIG. 1, FIG. 3 is a perspective view of a filter element thereof, and FIG. 10 is a perspective view of the dust collecting section of an electrostatic dust remover showing another example of the present invention, and FIG. 11 is a partially cutaway view of FIG. 10. FIG. 12 is a perspective view of the filter element.

First, the configuration of the main parts of the dust removal device of the present invention will be explained with reference to FIG.

A ceramic 56 as a solid insulator is provided around the first electrode 50 to which a positive DC high voltage is applied, and a second electrode 52 to which a negative potential is applied is placed across the ceramic 56. provided. These constitute an electrode unit.
In this case, the tip of the second electrode is arranged at a position recessed from the tip of the first electrode. This creates an electric field in that part due to the edge effect of that part, and the electric field guides floating particles to the filter element.

A ventilation path 60 is formed between the electrode units constructed in this way, and a filter element 61 is mounted in this ventilation path 60. This filter element 61 is made of metal wool made of extremely thin metal wires, such as steel wool, A1 wool, Cu wool, etc.

Therefore, when air containing suspended particles reaches the ventilation path 60, the suspended particles are guided to the filter element by the electric field generated at the tip of the electrode unit. When the suspended particles reach the filter element 61, if the suspended particles are positively charged, they contact the second electrode to which a negative potential is applied, and are kept at a negative potential. Coulomb force acts due to electrostatic induction between the hanging filter element 75 and the countless linear bodies having a large surface area, and is collected by the linear bodies. In addition, when the floating particles pass through the space in which the negative electrode is formed by the mesh-like filter element 75, they are apertured and are charged while repeatedly colliding or contacting each other, and are eventually affected by the Coulomb force described above. is collected on the linear body of the filter element. The collected particles are attached and retained as they are. Charge for this purpose is supplied from the second electrode.

Next, in FIGS. 10 to 12, 50 is a first electrode to which a positive DC high voltage is applied;
This electrode 50 is surrounded by ceramic 56 and molded. A first electrode unit _U1 is prepared in which second electrodes 52 to which a negative voltage is applied are arranged on both sides of the ceramic 56. Here, the tip of the second electrode 52 is located at a position farther back than the tip of the first electrode 50, and an electric field is generated at these ends. Further, a second electrode unit _U2 is prepared, which includes an electrode 50 to which a high positive voltage is applied to one side and a second electrode 52 to which a negative voltage is applied to the other side with a ceramic 56 in between. Here, each electrode unit
U ₁ and U ₂ are assembled a certain distance apart to form a ventilation path 60 . In that case, the second electrode unit _U2 described above is used as the electrode unit located at the end.

Between the electrode units assembled in this way, there is a partition plate 57, a lower spacing plate 58, and an upper spacing plate 5.
9 to form a partition and a plurality of ventilation paths.
Further, the electrode 50 is provided with a terminal 51 and the electrode 52 is provided with a terminal 53, and the electrodes having the same polarity are connected to each other by a connecting conductor 54. In this case, the number of ventilation paths may be one at the minimum, and the number of ventilation paths can be appropriately designed depending on the capacity and purpose of the dust removal device. Further, as shown in FIG. 12a, the filter element 61 is previously shaped to match the shape of the ventilation path. Further, as shown in FIG. 12b, the filter element is configured such that the linear bodies are distributed coarsely at the tip end thereof, that is, at the entrance side of the ventilation path, and gradually distributed densely toward the outlet. This makes it possible to equalize the amount of dust collected over the entire area of the filter element.

Next, the electrostatic dust removal device according to the present invention will be explained in detail with reference to FIGS. 1 to 3.

In these figures, 70 is a first electrode to which a positive DC high voltage is applied, 71 is a second electrode to which a negative potential is applied, and 72 is a solid insulator formed surrounding the first electrode 70. Ceramic as a
These constitute an electrode unit. As described above, the tip of the second electrode of this electrode unit is arranged so as to be set back from the tip of the first electrode. 73 is a side plate, 74 is a ventilation path,
75 is a filter element attached to the ventilation path, 76 is a pre-filter that collects coarse dust to prevent clogging of the filter element 75, 77 is a rear filter that also serves as a holder for the activated carbon filter, and 78 is activated carbon attached to the rear filter. 79 is a case body, 80 is a stopper, 81 is a grill, 82 is a fan, and 83 is an air outlet.

Therefore, air containing suspended particles is sucked in by the fan 82 from the grille 81 serving as a suction port, and reaches the dust collection unit via the prefilter 76.
This dust collection unit has a first part to which a positive potential is applied.
an electrode 70, a second electrode 7 to which a negative potential is applied.
1. Ceramic 72 formed between those electrodes
a filter element 76 disposed in a ventilation path 74 formed between these electrode units, a rear filter 77 at the end of the ventilation path 74, and an activated carbon filter 78. Here, as the filter element 76,
A sponge made of metal wool such as steel, A1, Cu, etc. or conductive plastic can be used, and this is pre-shaped to fit the shape of the ventilation path 74, as shown in FIG. , so that it can be easily inserted into the ventilation path 74. The prepared filter element may be inserted into the ventilation path 74. The assembled dust collection unit is then pushed into the case body 79 by being pushed from the grille 81 until it abuts the stopper 80 inside the case body 79. A fan 82 and a clean air outlet 83 are provided at the rear of the case body 79.

Therefore, when air containing suspended particles is sucked in by the fan 82 from the grille 81 serving as the suction port, the coarse dirt is collected by the prefilter 76, and the suspended particles in the air that have passed through it are collected by the electrodes 70, 71. The particles reach the filter element under the action of the electric field at the tip, and are collected by the above-mentioned dust collection action on the countless linear bodies having a large surface area of the filter element 75, which is maintained at a negative potential. The purified air is deodorized by the activated carbon filter 78 and then sent to the air outlet 83.
More blown out.

Here, when steel wool is used as the material for the filter element 75, SO ₂ , NOx
It has the effect of chemically adsorbing gas, etc., and can further purify the gas passing through the filter.

Additionally, such filter elements are suitable for use at high temperatures.

Furthermore, the strength and distribution of the electric field generated at the tip of the electrode unit described above depends on the voltage applied between the first electrode and the second electrode, the density of the linear body at the tip of the filter element, etc.

Although ceramic is used as an example of the solid insulator, it is not limited to this, and any material with high dielectric strength and high mechanical strength may be used. For example, epoxy resin may also be used. good. In the case of epoxy resin, a thin electrode unit can be easily constructed by forming an electrode made of a thin metal film on the surface of an epoxy resin plate.

Further, the thickness and shape of the solid insulator at the tip of the electrode unit can be appropriately designed depending on how the electric field strength and its distribution are selected.

Further, the present invention is not limited to the above embodiments, and various modifications can be made based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

(Effects of the Invention) As described above in detail, according to the present invention, the following effects can be achieved.

(1) Even when a high DC voltage is applied between the electrodes, the ceramic and epoxy resin interposed between the two electrodes have high insulation properties, and dust does not accumulate between the two electrodes, preventing short-circuit discharge. It can also reduce radio interference and ozone.

(2) The filter element that is in contact with the dust collection electrode is kept at the same potential as the dust collection electrode, and its surface area is extremely large, and due to electrostatic induction with particles floating in the air passing through it, Since the particles are collected, combined with the filtering action of the filter element itself as a physical filter material, higher dust collection efficiency can be achieved.

(3) Particles collected on the filter element can be maintained in an attached state by the electric charge supplied from the electrode unit.

(4) An electrode unit in which a counter electrode is disposed with a solid insulator interposed therebetween is structurally strong and simple, and can reduce costs.

(5) Each component material has high heat resistance, so it can withstand even high-temperature environments.

(6) The device can be made more compact.

(7) It is extremely easy to replace the filter element by simply removing it from the ventilation path and inserting a new filter element into the ventilation path before the dust collection efficiency decreases.

(8) The initial performance of the filter element can be updated by replacing it.

(9) Metal wool such as steel, A1, or Cu can be used for the filter element, which is inexpensive and can reduce maintenance costs. In particular, these metal wools can secure a wide surface area in the ventilation path and can improve dust collection efficiency.

(10) When still wool is used as the material for the filter element, it has the effect of chemically adsorbing SO ₂ , NOx, etc., and can further purify the gas passing through the filter.

(11) If the replaced filter element is made of steel wool, even if it is discarded as is, it will naturally oxidize and disappear due to oxygen and moisture in the air, and there is no risk of causing pollution.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an electrostatic dust remover according to the present invention, FIG. 2 is an exploded perspective view of the electrostatic dust remover shown in FIG. 1, FIG. 3 is a perspective view of its filter element, and FIG. The figure is an explanatory diagram of the dust collection principle of a conventional electrostatic precipitator, Figure 5 is a sectional view showing an example of an electrostatic precipitator that adopts the dust collection principle, and Figure 6 is an electrostatic dielectric air purification method. An explanatory diagram of the dust collection principle of the device, Figure 7 is a cross-sectional view of an electrostatic dielectric air purifier adopting the dust collection principle of Figure 6, Figure 8 is a configuration diagram of its filter element,
FIG. 9 is a configuration diagram of main parts of a dust removal device according to the present invention, FIG. 10 is a perspective view of a dust collecting section of an electrostatic dust removal device showing another example of the present invention, and FIG. 11 is shown in FIG. 10. FIG. 12 is a partially cutaway perspective view of the dust collecting section, and FIG. 12 is a perspective view of the filter element. 50,70...first electrode, 52,71...second electrode, 56,72...ceramic, 57...
Partition plate, 58... Lower spacing plate, 59... Upper spacing plate, 60, 74... Ventilation path, 51, 53... Terminal, 54... Connection conductor, 61, 62, 75... Filter element, 73... ... Side plate, 76 ... Prefilter, 77 ... Rear filter, 78 ... Activated carbon filter, 79 ... Case body, 80 ... Stopper, 81 ... Grill, 82 ... Fan, 83
...Air outlet.

Claims (1)

[Claims] 1 (a) A first electrode to which a positive potential is applied, the tip of which is located at a position set back from the tip of the first electrode, and facing each other with a solid insulator in between. (b) a ventilation path formed outside the second electrode; (c) an electrode unit attached to the ventilation path and connected to the second electrode; An electrostatic dust removal device comprising: (d) a forced ventilation means for venting the gas to be purified into the ventilation path; 2. The electrostatic dust removal device according to claim 1, wherein a plurality of dust collection units each including the electrode unit, the ventilation path, and the filter element are arranged in parallel. 3. The electrode unit in the dust collection unit disposed inside of the plurality of dust collection units arranged in parallel has a first electrode surrounded by a solid insulator and a second electrode on both sides of the solid insulator. 3. The electrostatic dust removal device according to claim 2, wherein the electrostatic dust removal device is arranged such that a dust removal device is provided therein. 4. The electrostatic dust removal device according to claim 1, wherein the first electrode and the second electrode are arranged in a parallel plate shape. 5. The electrostatic dust removal device according to claim 1, wherein the filter element is formed in advance to match the shape of the ventilation path. 6. The electrostatic dust removal device according to claim 1, wherein the filter element is made of metallic wool. 7. The electrostatic dust removal device according to claim 6, wherein the metallic wool is steel wool. 8. The electrostatic dust removal device according to claim 1, wherein the forced ventilation means is a motor-driven fan provided at the rear end of the ventilation path. 9. Claim 1, characterized in that a pre-filter is provided in the front part of the ventilation path.
Electrostatic dust removal device as described in section. 10. The electrostatic dust removal device according to claim 1, characterized in that an activated carbon filter is provided at the rear of the ventilation path. 11. The electrostatic dust removal device according to claim 1, wherein the solid insulator is ceramic. 12. The electrostatic dust removal device according to claim 1, wherein the solid insulator is an epoxy resin.