JP3526494B2 - Charged air filter device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charge type air filter device. ADVANTAGE OF THE INVENTION According to the air filter apparatus of this invention, an electrostatic attraction can be utilized and the dust in a to-be-processed gas (especially air) can be collected and a to-be-processed gas can be purified and an air cleaner. Alternatively, it can be used in a dust collector or the like.

[0002]

2. Description of the Related Art Conventionally, as an air cleaner or a dust collector that collects dust in the air by utilizing electrostatic attraction to purify the air, or an air filter device used therefor, (1) Corona An electrostatic precipitator including a pre-charging part for charging dust by discharge and a collecting electrode part such as a parallel plate electrode. (2) An electric field is applied to a fibrous dielectric to generate an electrostatic force induced on the fiber surface. Dielectric filters that utilize dust to be collected, and (3) electret filters that use a filter medium that has been previously charged by corona discharge or the like have been generally known. In the electrostatic precipitator (1), for example, as shown in FIG. 1, a precharging portion 3 including a discharge electrode 2 such as a needle electrode and a counter electrode 1 such as a flat plate electrode grounded is indicated by an arrow A. It is provided on the inlet side of the air to be treated flowing in from the direction, and on the downstream side thereof is provided the parallel plate electrode 4 arranged substantially parallel to the flow of the air to be treated. When a DC high voltage is applied between the discharge electrode 2 and the counter electrode 1, DC corona discharge occurs, and the dust contained in the air passing through the preliminary charging unit 3 is charged unipolarly. The charged dust is collected by the parallel plate electrode 4 arranged downstream thereof. However, in such an electrostatic precipitator (1), since it is necessary to continuously charge the dust during the dust collecting process, it is necessary to continuously discharge the precharging unit 3 continuously, and the power consumption is reduced. It has a large defect that ozone is continuously generated. In addition, dust charged by corona discharge may adhere to the pre-charging portion 3, so that the discharge performance is deteriorated and the dust collection efficiency is deteriorated. Furthermore, since it is necessary to apply a high voltage (high electric field strength) to the preliminary charging unit 3, there is a risk of ignition due to spark discharge.

According to the above-mentioned dielectric filter (2), for example, on the surface of a dielectric fiber body formed into a flat plate shape,
When a mesh electrode made of metal or the like is formed and a DC voltage is applied to the electrode, the dielectric fiber body is dielectrically polarized. The electrostatic attraction thus generated can collect the dust in the air to be processed passing through the fibrous body. In such a dielectric filter (2), the risk of ignition due to spark discharge is small, but since the dust is collected by the electrostatic attraction due to the dielectric polarization action of the dielectric, there is a drawback that the dust collection efficiency is low. Furthermore, in the above electret filter (3), the effect of the electret deteriorates with the passage of time as in the case of a general electret product. The major drawback was that the filter had to be replaced in a short period of time. Further, in order to improve the initial dust collection efficiency, it is preferable to use a material with a large amount of electrification as the electret material, but in this case the electrification life becomes short, while on the other hand, it is necessary to lengthen the replacement interval, If the material is selected by placing importance on the charge life rather than the charge amount, there is a drawback that the initial dust collection efficiency is not always satisfactory.

[0004]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an air filter device utilizing electrostatic attraction, which can effectively charge a filter medium with a small electric field strength and has a high dust collection efficiency. Moreover, it is an object of the present invention to provide an air filter device in which continuous energization is not required during use of the air filter device, and the filter replacement interval is very long as compared with the electret filter.

[0005]

According to the present invention, the above object is to provide a filter medium composed of a chargeable material, a pair of positive ion and / or negative ion generating means, and any one of the above ion generating means. Any one of positive polarity ions or negative polarity ions generated by one side can be selectively attracted, and a pair of ion attracting electrodes provided corresponding to each of the pair of ion generating means is included. A charge type air filter device, wherein at least when charging the filter medium, a pair of ion generating means is provided between the first ion generating means and the second ion generating means which are arranged facing each other. And the first ion-attracting electrode may be arranged on the side opposite to the first ion generating means with respect to the filter medium, Only one kind of the positive ions or negative ions generated by the ion generating means,
The second ion-withdrawing electrode can be moved from the first ion generating means to the filter medium, and the second ion-withdrawing electrode is arranged on the opposite side of the second ion generating means with respect to the filter medium, Of the ions generated by the ion generating means,
Only ions of the opposite polarity to the ions transferred to the filter medium from the first ion generating means can be transferred to the filter medium from the second ion generating means, and the first ions are The inflow surface and outflow surface of the gas to be treated in the filter medium are charged by the ions transferred from the generating means to the filter material and the ions transferred from the second ion generating means to the filter material, respectively. Can be achieved with a pneumatic air filter device.

[0006]

SUMMARY OF THE INVENTION Therefore, the present invention provides
(1) A filter medium made of a chargeable material, and (2) a first generating both or one of positive and negative ions.
Ion generating means and a second ion generating means for generating both or the other of the positive polarity ion and the negative polarity ion (however, the above-mentioned first ion generation means and second ion generation means). When the means generate one of the positive ion and the negative ion, respectively, the polarity of the ion generated by the first ion generating means and the polarity of the ion generated by the second ion generating means. And (3) when both positive and negative ions are generated in the first ion generating means, any one of them is selectively sucked and the first ion is generated. When either the positive ion or the negative ion is generated in the generating means, the first ion attracting electrode for attracting the generated ion and the positive ion in the second ion generating means When both negative ions are generated, any one of them is selectively sucked, and when either the positive ions or the negative ions are generated in the second ion generating means, the generated ions are sucked. And a pair of attractive electrodes composed of a second ion attractive electrode, wherein (a) first ions arranged to face each other when at least the filter medium is charged. A filter medium is disposed between the generating means and the second ion generating means in a non-contact state with them, and (b) the first ion attracting property is provided on the other side of the filter medium as seen from the first ion generating means. When both positive and negative ions are generated in the first ion generating means by disposing electrodes, any one of them is selectively moved to the filter medium to generate the first ion generating device. Means positive When one of the ON or negative polarity ions is generated, the generated ion is moved to the filter medium, and (c) the second ion attracting property is provided on the other side of the filter medium as seen from the second ion generating means. When both electrodes are arranged and both positive and negative ions are generated in the second ion generating means, the polarity opposite to that of the ions transferred from the first ion generating means to the filter medium is used. Only the ions of No. 1 are selectively moved to the filter medium, and when one of the positive ion and the negative ion is generated in the second ion generating unit, the ions are moved from the first ion generating unit to the filter medium. The generated ions are transferred to the filter medium with the opposite polarity to the ions, and the ions transferred from the first ion generating means to the filter medium and the ions transferred from the second ion generating means to the filter medium This can be achieved by a charge-type air filter device characterized in that the inflow surface and the outflow surface of the gas to be treated in the filter medium are electrically charged by the ions.
In a preferred aspect of the device of the present invention, the first ion generating means and the second ion generating means are each selected from the group consisting of an AC surface discharge element, an ionizer element, a DC corona type ion generating element, and an AC corona type ion generating element. It is an ion generating means independently selected. In another preferred aspect of the device of the present invention, the first ion generating means and the second ion generating means are both AC creeping discharge elements that generate both positive and negative ions. AC surface discharge element as the first ion generating means of the
By applying different direct-current potentials to the AC creeping discharge element as the ion generating means and forming a DC electric field between them, the first ion generating means causes the second ion attracting electrode to operate. To suck only one of the positive and negative ions, and similarly, the second ion generating means acts as the first ion attracting electrode to suck the second ion. Ions that are opposite in polarity to the ions that the positive electrode attracts are attracted. Furthermore,
In another preferred aspect of the device of the present invention, the first ion generating means is an ionizer element for generating positive ions, and the second ion generating means is an ionizer element for generating negative ions, and the first ion The attracting electrode is an electrode that attracts positive ions, and the second ion attracting electrode is an electrode that attracts negative ions. In still another preferred embodiment of the device of the present invention, the first ion generating means is a direct current corona type ion generating element which generates positive ions, and the second ion generating means is a direct current which generates negative ion. A corona type ion generating element, wherein different direct current potentials are applied to the DC corona type ion generating element as the first ion generating means and the DC corona type ion generating element as the second ion generating means, By forming a DC electric field between them, the first
Of the second ion generating means acts as a second ion attracting electrode to attract negative ions, and similarly, the second ion generating means acts as a first ion attracting electrode and positive polarity. Aspirate ions. In still another preferred aspect of the device of the present invention, both the first ion generating means and the second ion generating means generate an AC corona type ion generating element that generates both positive and negative ions. And applying different DC potentials to the AC corona type ion generating element as the first ion generating means and the AC corona type ion generating element as the second ion generating means, respectively, and applying a DC voltage between them. By forming a field, the first ion generating means acts as a second ion attracting electrode to attract only one of the positive ion and the negative ion. The second ion generating means acts as the first ion attracting electrode and attracts the ion having the opposite polarity to the polarity of the ion attracted by the second ion attracting electrode.

The apparatus of the present invention can be used for treating any gas (for example, air) to remove and purify dust contained in the gas to be treated.
In the device of the present invention, a charged filter medium can be used to purify the gas, but in the device of the present invention, (1) a charging mode for charging the filter medium (hereinafter, may be simply referred to as "charge mode") And (2) an aeration mode in which a gas is treated using a charged filter medium (hereinafter, may be simply referred to as “aeration mode”). Here, the above-mentioned charging mode refers to an operation operation in which only the charging process of the filter medium is carried out and the gas process is not carried out during the charging process. On the other hand, the ventilation mode refers to an operation operation in which only the gas treatment is performed using the charged filter medium in the charging mode and the filter medium is not charged. Further, in the device of the present invention, it is possible to perform an operation operation for purifying the gas at the same time as charging the filter medium, and this operation operation is referred to as a "charge ventilation mode" in distinction from each of the above modes. . Therefore, the apparatus of the present invention can be operated by an operation operation for intermittently charging the filter medium, that is, a cycle of the charging ventilation mode and the ventilation mode while continuously performing the gas purification process.

[0008]

DETAILED DESCRIPTION OF THE INVENTION The charging mode of the device of the present invention will be described first. FIG. 2 shows a typical embodiment of the air filter device of the present invention, which uses an AC creeping discharge element as a pair of ion generating means required for charging the filter medium. In this aspect, at least in the charging mode, the two AC creeping discharge elements 21, 22 are arranged so as to face each other with a predetermined space therebetween, and they are in the middle of these elements in a non-contact state with each of them. A filter 11 as a filter material is arranged. In the case of the pleated filter 11 as shown in FIG. 2, an AC creeping discharge element 22 is arranged upstream of the treated gas inflow side of the pleated filter 11 so as to face the inflow side. On the other hand, filter 1
An AC creeping discharge element 21 is arranged at the downstream side of the outflow surface side of No. 1 to be treated so as to face the outflow surface side. As each AC creeping discharge element, for example, as shown in FIG. 3, the induction electrode 51 is inserted into the central axis of a cylindrical dielectric body 31 made of glass or ceramic, and a coil shape is formed on the side surface of the dielectric body 31. The AC creeping discharge element 21 in which the discharge electrode 41 is wound and carried can be used. Alternatively, use an AC surface discharge element in which a sheet-shaped dielectric is wound around and covered on the side surface of a rod-shaped induction electrode, and a coil-shaped discharge electrode is wound around the outermost layer of the dielectric and carried. You can

The discharge electrodes 41 and 42 and the induction electrodes 51 and 52 of the AC surface discharge elements 21 and 22 are connected to AC power sources 61 and 62, respectively, as shown in FIG. Generally, when a creeping discharge is generated by using an AC creeping discharge element, the discharge electrode is grounded, whereas in the present invention, the discharge electrodes 41 and 42 are connected to the DC power sources 71 and 72, respectively.
Connect to. Generally, the AC power supplies 61 and 62 are composed of an AC generator and a transformer, and the DC power supplies 71 and 72 can be connected from the secondary side ground terminal of the transformer.

When an AC high voltage is applied from the AC power supplies 61 and 62, ionization occurs from the discharge electrodes 41 and 42 along the discharge electrode supporting surface of the dielectric surface, and both positive and negative ions are generated. Creeping discharge occurs. At the same time, the discharge electrodes 41 from the DC power supplies 71 and 72 are simultaneously discharged.
When DC voltages V1 and V2 having different potentials are applied to the and 42, a DC electric field (hereinafter sometimes referred to as a charging electric field) is formed between the AC creeping discharge elements 21 and 22.
For example, in each AC creeping discharge element 21, 22 generated when a positive voltage V1 is applied to the discharge electrode 41 of the AC creeping discharge element 21 and a negative voltage V2 is applied to the discharge electrode 42 of the AC creeping discharge element 22. The AC waveform is shown in FIG. That is, the earth potential (0 V: FIG.
Since a DC positive potential V1 (a in FIG. 4) is applied to x) in FIG. 4, the AC wave of the induction electrode 51 (b in FIG. 4) is boosted by the DC component V1 and the potential of the discharge electrode 41 is also V1. Becomes
On the other hand, since the DC negative potential V2 (c in FIG. 4) is applied to the earth potential (0 V: x in FIG. 4) to the AC creeping discharge element 22, the AC wave of the inducing electrode 52 (d in FIG. 4) is applied. ) Lowers only the DC component V2, and the potential of the discharge electrode 42 also becomes V2.

When a charging electric field is formed between the AC creeping discharge elements 21 and 22 in this way, the discharge electrodes 41 and 42 act as ion-attracting electrodes for the AC creeping discharge elements 22 and 21 facing each other. . That is, of the positive and negative ions generated on the dielectric surface of the AC creeping discharge element 21, only positive ions are selectively attracted to the discharge electrode 42 of the AC creeping discharge element 22, which is set to a negative potential. Then, it moves in the direction of the AC creeping discharge element 22, adheres to the gas inflow surface of the filter 11 disposed in the middle thereof, and charges the gas inflow surface of the filter 11. On the other hand, of the positive and negative ions generated on the dielectric surface of the AC creeping discharge element 22, only negative ions are selectively attracted to the discharge electrode 41 of the AC creeping discharge element 21 set to the positive potential. And moved in the direction of the AC creeping discharge element 21,
It adheres on the gas outflow surface of the filter 11 disposed in the middle of the process and charges the gas outflow surface of the filter 11.
Thus the filter 11 is simultaneously treated with positive ions from one side and negative ions from the other side, and both sides of the filter 11 are highly heterogeneously charged (ie charged with both positive and negative ions).

The DC voltages V1 and V2 need only be different from each other, and one may be ground and the other may be a positive potential or a negative potential. In this case, the discharge electrodes 41 and 42 act as ion-attracting electrodes for the AC surface discharge elements 22 and 21 facing each other.
Of the positive and negative ions generated on the surfaces of the dielectrics 1 and 22, only one of the positive and negative ions is the discharge electrode 4 of the AC creeping discharge element 22, 21.
2 and 41 are selectively attracted to the AC creeping discharge element 2
It moves in the direction of 2, 21 and adheres to the filter 11 arranged in the middle thereof to charge the filter 11. It should be noted that, for example, capacitors or chokes may be provided in the mechanism of the DC power supply devices 71 and 72 to prevent AC waves from directly entering the DC power supply and protect the DC power supply.

The high frequency AC voltage applied by the AC power source to generate the creeping discharge is not particularly limited, but is preferably 0.2 KVp-p or more, more preferably 1 KVp-p or more (KVp-p). p represents a voltage difference from the maximum value peak to the minimum value peak of the AC voltage), and the frequency is not particularly limited, but preferably 0.1 to 100 KHz, more preferably 1 to 50 KH.
z. When the voltage is less than 0.2 KVp-p, the discharge does not substantially occur, and when the frequency is less than 0.1 KHz, an extremely large voltage is required for the discharge.
If the frequency exceeds KHz, there is a problem that the dielectric material is overheated by dielectric heating and may be destroyed.

The DC potential difference applied to the discharge electrodes 41 and 42 is not particularly limited either, but the electric field strength of the charging electric field formed between the discharge electrodes 41 and 42 is preferably 10.
0 V / cm or more, more preferably 500 to 5000 V /
It is applied so that it becomes cm. Electric field strength is 100V / cm
When the amount is less than the above, the effective amount of ions used for charging becomes extremely small, and even if the charging time is extremely lengthened, the substantial amount of charge becomes small, and a sufficient electret effect cannot be obtained. In the air filter device of the present invention,
Since the voltage applied to form the charging electric field and the voltage applied to generate the ions are substantially independent, the final charge amount does not depend on the electric field strength between the ion attracting electrodes. , And depends only on the potential difference between them. Therefore, the electric field strength of the charging electric field can be reduced (when a very high charging voltage is applied, the space between the electrodes should be widened), and there is no danger of spark discharge.

According to the above charging mode, the filter 11
Is sufficiently charged, the application of the AC high voltage from the AC power supplies 61 and 62 and the DC voltage from the DC power supplies 71 and 72 is stopped, and the electretization process of the filter, that is, the charging mode is ended. Subsequently, when the gas to be treated containing dust is passed through the electretized filter 11 by converting to the ventilation mode, electrostatic attraction causes
The dust contained in the gas to be treated is collected by the filter 11 and the gas to be treated can be purified. During the purification process of the gas to be processed, it is not necessary to apply the AC high voltage from the AC power supplies 61 and 62 and the DC voltage from the DC power supplies 71 and 72, and the electretization process can be completed in a short time. It is possible to suppress the power consumption required for the above, and to reduce the ozone generation amount. Further, by separately performing the charging and the ventilation as described above, the adhesion of dust contained in the gas to be treated to the discharge electrode can be reduced as compared with the case where the charging and the ventilation are performed simultaneously. Since the effect of the electret deteriorates if the electretized filter 11 is used for a long period of time,
The dust collection efficiency decreases with time as compared with the sufficient dust collection efficiency immediately after the electret treatment. In this case, the ventilation mode is interrupted, the charging mode is replaced again, and the electretization process of the filter is repeated again, whereby sufficient dust collection efficiency can be recovered. In the device of the present invention,
As described above, the operation can be performed while switching between the charging mode and the ventilation mode. Further, since the electretization process can be completed in a short time, it is possible to operate while switching between the charging ventilation mode and the ventilation mode without stopping the gas purification process.

In the device of the present invention, a known element can be used as the AC creeping discharge element. FIG. 2 shows a mode in which a plurality of columnar AC creeping discharge elements are used.
The AC creeping discharge element can have various shapes. For example, a flat plate AC creeping discharge element as shown in FIG. 5 can be used. AC creeping discharge element 21 shown in FIG.
Carries the discharge electrode 41 on one surface of the dielectric 31,
It has a structure in which the induction electrode 51 is carried on the other surface,
When an AC high voltage is applied, ionization occurs from the discharge electrode 41 along the discharge electrode carrying surface side of the surface of the dielectric 31, and both positive and negative ions are generated to generate a creeping discharge. It is desirable that the discharge electrode 41 has a structure having an opening so that the dielectric 31 is exposed on the surface from below the discharge electrode 41.

As the dielectric 31 of the AC creeping discharge element 21 that can be used in the present invention, for example, plate-shaped or sheet-shaped glass, ceramic or plastic can be used. The thickness of the dielectric is not particularly limited, but if it is too thick, a very high voltage is required to discharge,
If it is too thin, mechanical strength is lowered and dielectric breakdown is likely to occur, so that a thickness of about 0.1 to 5 mm is preferable. As the discharge electrode 41 of the AC creeping discharge element 21, one in which conductive paint is applied to the surface of a plastic film or the like, a grid electrode or a mesh electrode is formed by a metal layer or a conductive resin layer, or aluminum or copper A coil-shaped electrode, a grid-shaped electrode, a mesh-shaped electrode, or the like formed of a conductive metal or the like is suitable.

The inducing electrode 51 is not particularly limited, either, but a conductive paint is applied to the surface of a plastic film or the like, a flat plate electrode or a net electrode is formed by a metal layer or a conductive resin layer, or aluminum. A linear electrode, a flat plate electrode, or a net electrode formed of a conductive metal such as copper or the like is suitable. In the AC creeping discharge element, the length of the dielectric is preferably longer than the length of the discharge electrode and the inducing electrode so that direct discharge does not occur between the discharge electrode and the inducing electrode at the end of the AC creeping discharge element. When the length of the dielectric cannot be made sufficiently long, the end face of the induction electrode or the entire induction electrode may be insulation-coated with a dielectric such as a ceramic film or a polymer film. Further, it is preferable to cover the discharge electrode with a dielectric film such as a ceramic film or a polymer film because it is possible to prevent the discharge electrode from being consumed due to creeping discharge.

In the apparatus of the present invention, the pair of ion generating means, the pair of ion attracting electrodes provided corresponding to each of the pair of ion generating means, and the filter medium are arranged at least in the charging mode. , A pair of ion generating means and a pair of ion attracting electrodes,
It is sufficient that at least a part of each of the inflow surface and the outflow surface of the gas to be treated of the filter medium (preferably the entire surface of each of the inflow surface and the outflow surface) can be charged. Therefore, in the ventilation mode, the filter medium, the ion generating means and / or the ion attracting electrode may be the same as the position in the charging mode or may be moved from the position in the charging mode. Particularly, in the ventilation mode, if the ion generating means and / or the ion attracting electrode is moved from the flow path of the gas to be treated, it is possible to reduce dust and the like from adhering to the discharge electrode. According to the device of the present invention, the surface of the filter medium is mainly charged, but at that time, the inside of the filter medium, which is weaker than the surface charge, is also charged at the same time. In the present invention, such charges are also included in the surface charges for description.

A cylindrical element 2 as shown in FIGS. 2 and 3.
By disposing a plurality of the gases 1 and 22 on the inflow surface side and the outflow surface side of the gas to be treated, even if they are arranged in the flow path of the gas to be treated, the air permeability is not significantly reduced, so that After the end, the AC creeping discharge elements 21, 22
May be moved to the ventilation mode as it is without being moved from the front and rear of the filter medium 11. Of course, the cylindrical AC surface discharge elements 21 and 22 may be moved from the front and the rear of the filter medium 11 before shifting to the ventilation mode. When the gas treatment is continuously performed, the filtering treatment may be performed without interrupting the ventilation treatment. In this case, the filter medium is charged by using the pair of ion generating means and the pair of ion attracting electrodes, and at the same time, the aeration treatment is performed, and after the charging processing, if necessary, the pair of ion generating means and the pair of ion attracting electrodes are attracted. The positive electrode is moved from before and after the filter medium. Further, in the air filter device of the present invention, a pre-charging portion capable of charging the gas to be treated in the ventilation mode or the charging ventilation mode may be provided on the upstream side of the filter medium. As such a pre-charging portion, for example, as shown in FIG. 1, a pre-charging portion 3 including a discharge electrode 2 such as a needle electrode and a counter electrode 1 such as a flat plate electrode grounded can be cited. Discharge electrode 2 and counter electrode 1 in ventilation mode or charged ventilation mode
When a DC high voltage is applied between the and, a DC corona discharge occurs, and the dust contained in the gas to be processed passing through the precharging unit 3 is charged unipolarly, so that it is efficiently collected by the filter medium. .

Further, in the air filter device of the present invention, various arrangements can be used in addition to the arrangement shown in FIG. 2 in which at least a part of each of the inflow surface and the outflow surface of the gas to be treated of the filter medium can be charged. There are modes. For example, as shown in FIG. 6, the facing surfaces of the ion generating means and the corresponding ion attracting electrodes are deflected with respect to the inflow surface and the outflow surface of the gas to be treated of the filter medium so that the ion generating means and the ion attracting electrodes are disposed. It is also possible to dispose the target gas from the flow path (at least from the center of the flow path). In such an arrangement, a flat plate type AC creeping discharge element as shown in FIG. 5 can be advantageously used.

Specifically, two flat plate AC surface discharge elements 21 and 22 as shown in FIG. 5 are provided as shown in FIG.
The filters 11 are arranged so as to face each other with a predetermined space therebetween, and the filter 11 is arranged in the middle of these elements in a non-contact state with the elements. The inflow surface of the gas to be processed of the filter 11 is the flow of the gas to be processed (direction shown by arrow A).
It is arranged so that it is orthogonal to. On the other hand, filter 1
The AC creeping discharge element 22 is arranged on the upstream side of the upper space near the inflow surface of 1, and the AC creeping discharge element 21 is arranged on the downstream side of the lower space near the outflow surface of the filter 11. At that time, it is preferable that the discharge electrode carrying surfaces of the flat plate AC surface discharge elements 21, 22 are arranged in parallel to each other.
Contrary to the arrangement of FIG. 6, an AC creeping discharge element 22 is arranged upstream of the lower space near the inflow surface of the filter 11, and an AC creeping discharge element is further downstream of the upper space near the outflow surface of the filter 11. 21 can also be arranged. Furthermore,
An AC creeping discharge element 22 is arranged on the upstream side of the left (or right) space near the inflow surface of the filter 11, and an AC creeping discharge element 21 is further arranged on the downstream side of the right (or left) space near the outflow surface of the filter 11. May be arranged.

According to the above arrangement in which the ion generating means and the ion attracting electrode are not arranged in the main flow path of the gas to be treated, the air permeability is not reduced or is small,
The device of the present invention can be operated by simply switching between the charging mode and the ventilation mode without changing the arrangement of the discharging element and the filter medium in the charging mode. Further, even if the device of the present invention is operated in the charge ventilation mode, the adhesion of dust to the discharge electrode is reduced as compared with the case where the ion generating means and the ion suction electrode are arranged in the flow path of the gas to be treated. preferable. As shown in FIG. 2, two flat plate AC surface discharge elements 21 and 22 as shown in FIG. 5 are arranged in front of the treated gas inflow surface and outflow surface of the filter medium to carry out the charging mode. Subsequently, the ventilation mode may be performed after moving the discharge element from the flow path of the gas to be treated (at least from the center of the flow path).

Further, as shown in FIG. 7, the cylindrical filter 11 can be charged using a pair of cylindrical AC creeping discharge elements 21, 22. Specifically, the cylindrical AC creeping discharge element 21 having a large diameter and the cylindrical AC creeping discharge element 22 having a small diameter are arranged concentrically with a predetermined space. Each AC creeping discharge element 21, 22 is
The discharge electrode 4 is provided on one surface of each of the dielectrics 31 and 32.
1, 42, and the induction electrodes 51, 52 on the other surface.
The two AC creeping discharge elements 21, 22 are arranged so that the surfaces carrying the discharge electrodes 41, 42 face each other. Discharge electrodes 41 and 42 and induction electrode 5
1, 52 are connected to an AC power source (not shown), respectively, as in the embodiment shown in FIG.
Are respectively connected to a DC power source (not shown). A filter 11 is arranged between the AC creeping discharge elements 21 and 22 in a non-contact state with these elements. In the air filter device of the present invention shown in FIG. 7, the gas to be treated flowing into the intake gap 12 formed by being sandwiched between the AC creeping discharge element 22 and the filter 11 passes from the inside of the filter 11 to the outside thereof, Creepage discharge element 21 and filter 1
It flows out into the exhaust gas gap 13 formed by being sandwiched between 1 and 1. Therefore, in the arranged filter 11, the inflow surface of the gas to be processed is orthogonal to the flow of the gas to be processed.

Contrary to the embodiment of FIG. 7, the AC creeping discharge element 2
1. The gas to be treated that has flowed into the intake air gap formed between the filter 1 and the filter 11 is passed from the outside to the inside of the filter 11, and the exhaust gas gap is formed between the AC creeping discharge element 22 and the filter 11. It can also be drained to. According to the above arrangement in which the ion generating means and the ion attracting electrode are not arranged between the main flow path of the gas to be treated (that is, the intake gap and the exhaust gap) and the filter, the air permeability is not deteriorated, or Since there are few, without changing the arrangement of the discharge element and the filter medium in the charging mode,
The device of the present invention can be operated by simply switching between the charging mode and the ventilation mode. The device of the present invention may be operated in the charging ventilation mode.

In the air filter device of the present invention, the size of the pair of ion generating means, and the size of the pair of ion attracting electrodes corresponding to each, is the conditions of use, for example, the size of the air filter device of the present invention. It can be appropriately selected according to the size of the treated gas purifier or the dust collector, the size of the filter, or the like, and is not particularly limited, but it is not particularly limited, but is applied between the ion generating means and the ion attracting electrodes by the application of the DC voltage. The size is preferably such that each of the charging electric fields formed contains most of the gas inflow surface and the outflow surface of the filter medium.

The present invention can be carried out by using an ionizer element as the ion generating means, and a typical mode in which the ionizer element is used as each ion generating means is shown in FIG. In this embodiment, the two ionizer elements 24 and 25 are arranged with a predetermined space therebetween. Each of the ionizer elements 24 and 25 is a direct current corona discharge electrode 8 including a wire electrode, a needle electrode, etc.
4a, 85a, earth electrodes 84b, 85b, and guide plates 84c, 8 for sending generated ions into the charging space.
5c, the discharge electrodes 84a and 85a are connected to the DC high-voltage power supplies 74a and 75a (however, 74a and 75a have opposite polarities), and the ground electrodes 84b and 85b are respectively connected to the ground. Two ionizer elements 24, 25
Generates positive ions and negative ions by applying a DC high voltage, respectively, and the reaction gas (for example, air) supplied from the direction indicated by the arrow B causes the guide plates 84c and 85c to move the arrow C Is emitted in the direction indicated by.

On the other hand, the ion attracting electrodes 44 and 45 communicate with the DC power supplies 74a and 75a, respectively, and 84a and 85, respectively.
Since the potential polarity is the same as that of a, the ion attracting electrode 44 exerts an attracting action on the ions ejected from the guide plate 85c, and the ion attracting electrode 45 attracts the ions ejected from the guide plate 84c. Exert. For example,
As shown in FIG. 8, the positive ions released from the ionizer element 24 are attracted to the ion attracting electrode 45 and move toward the ion attracting electrode 45, and the gas inflow surface of the filter 11 disposed in the middle thereof And charges the gas inflow surface of the filter. On the other hand, the ionizer element 2
The negative ions released from No. 5 are attracted to the ion attracting electrode 44, move toward the ion attracting electrode 44, and adhere to the gas outflow surface of the filter 11 disposed in the middle thereof, and the gas outflow surface of the filter. To charge. Thus, the filter 11 is simultaneously treated and heterocharged with positive ions from one side and negative ions from the other side.

According to the above charging mode, the filter 11
Is sufficiently charged, the discharge is stopped and the electretization process of the filter, that is, the charging mode is ended. Then, if necessary, the ion attracting electrodes 44, 4
5, and optionally, ionizer elements 24, 25
Is moved away from the flow path of the gas to be treated, converted into the ventilation mode, and the electretized filter 11
When the gas to be treated containing dust passes through the filter 1, the dust contained in the gas to be treated is filtered by the electrostatic attraction.
It is possible to purify the gas to be treated by collecting the gas to be treated. During the purification process of the gas to be treated, it is not necessary to apply voltage,
Since the electretization process can be completed in a short time, it is possible to suppress the power consumption required for charging the filter, and it is possible to reduce the ozone generation amount. Since the effect of the electret deteriorates when the electretized filter 11 is used for a long period of time, the dust collecting efficiency decreases with time as compared with the sufficient dust collecting efficiency immediately after the electret treatment. In this case, the ventilation mode is interrupted, the charging mode is replaced again, and the electretization process of the filter is repeated again, whereby sufficient dust collection efficiency can be recovered. The device of the present invention can be operated while switching between the charging mode and the ventilation mode. Further, since the electretization process can be completed in a short time, it is possible to operate while switching between the charging ventilation mode and the ventilation mode without stopping the gas purification process.

In the present invention, a DC corona type ion generating element can be used as the ion generating means, and a typical mode in which the DC corona type ion generating element is used as each ion generating means is shown in FIG. In this embodiment, the two DC corona type ion generating elements 26, 27 are
It is arranged so as to face a predetermined space. Each DC corona type ion generating element 26, 27 has a counter electrode 86.
a, 87a and discharge electrodes 86b, 87b, and counter electrodes 86a, 87a are DC power sources 76a, 77a, respectively.
(However, the DC power supplies 76a and 77a have opposite polarities), and the discharge electrodes 86b and 87b are connected to the DC power supply 76, respectively.
b, 77b (however, the discharge electrodes 76b and 77b have opposite polarities). In the DC corona type ion generating elements 26 and 27 shown in FIG.
Although a, 87a and four discharge electrodes 86b, 87b are provided, the number of electrodes can be changed according to the environment or purpose of use. The discharge electrodes 86b and 87b are not particularly limited as long as they have a shape capable of causing corona discharge, and for example, linear electrodes or needle electrodes can be used.

In the DC corona type ion generating element 26, the counter electrodes 86 are respectively supplied from the DC power supplies 76a and 76b.
DC voltages V11 and V12 having the same polarity and different potentials are applied to a and the discharge electrode 86b. Voltage V1
When the potential difference between 1 and V12 is larger than the electric field strength at which corona discharge occurs and the absolute value of the voltage V12 is larger than the absolute value of the voltage V11, the polarity of the voltage applied by the DC power supplies 76a and 76b is the same. Ion is the counter electrode 86
It is generated between a and the discharge electrode 86b. At the same time,
Also in the DC corona type ion generating element 27, a DC voltage having a polarity opposite to the voltage polarity applied by the DC power supplies 76a and 76b from the DC power supplies 77a and 77b to the counter electrode 87a and the discharge electrode 87b, respectively, and having a different potential. Applying V13 and V14, the potential difference between the voltages V13 and V14 is larger than the electric field strength at which corona discharge occurs,
When the absolute value of the voltage V14 is larger than the absolute value of the voltage V13, the counter electrode 8 of the DC corona ion generating element 26 is
Ions having the opposite polarity to the ions generated between 6a and the discharge electrode 86b are generated between the counter electrode 87a and the discharge electrode 87b.

For example, a negative voltage V11 is applied to the DC power supply 76a connected to the counter electrode 86a, a negative voltage V12 is applied to the DC power supply 76b connected to the discharge electrode 86b, and the absolute value of the negative voltage V12 is calculated. It is set to be larger than the absolute value of the negative voltage V11, and the potential difference between the voltage V11 and the voltage V12 is set to be larger than the electric field strength at which corona discharge occurs. On the other hand, at the same time, a positive voltage V13 is applied to the DC power supply 77a communicating with the counter electrode 87a, a positive voltage V14 is applied to the DC power supply 77b communicating with the discharge electrode 87b, and the positive voltage V14 is changed from the positive voltage V13. Also larger, and voltage V
The potential difference between the voltage V13 and the voltage V14 is set to be larger than the electric field strength at which corona discharge occurs. Thus, negative ions are generated between the counter electrode 86a and the discharge electrode 86b of the DC corona type ion generating element 26, and the positive polarity is generated between the counter electrode 87a and the discharge electrode 87b of the DC corona type ion generating element 27. Ions are generated.

At the same time, since a DC electric field (charging electric field) is formed between the DC corona type ion generating element 26 and the DC corona type ion generating element 27, the counter electrode 87a and the discharge electrode 87b face each other. The DC corona type ion generating element 26 acts as an ion attracting electrode, and the counter electrode 86a and the discharge electrode 86b act as an ion attracting electrode with respect to the facing DC corona type ion generating element 27. For example, when the voltages V11 to V14 illustrated above are applied, the negative ions generated in the DC corona ion generating element 26 are set to the positive potential of the DC corona ion generating element 27 and the counter electrode 87a and the discharge electrode. 87b is attracted and moves toward the DC corona type ion generating element 27,
It adheres to the gas inflow surface of the filter 11 arranged in the middle thereof and charges the gas inflow surface of the filter. on the other hand,
The positive ions generated in the DC corona type ion generating element 27 are attracted to the counter electrode 86a and the discharge electrode 86b which are set to the negative potential of the DC corona type ion generating element 26, and the direction of the DC corona type ion generating element 26 is increased. To the gas outflow surface of the filter 11 disposed on the way to charge the gas outflow surface of the filter. Thus, the filter 11 is simultaneously treated with negative ions from one side and positive ions from the other.

The distance between the counter electrode and the discharge electrode capable of causing DC corona discharge is preferably about 1 mm to 20 mm, and the potential difference between them is preferably about 0.1 KV to 20 KV, although it depends on the electrode shape or distance. . The potential difference between the DC corona type ion generating element 26 and the DC corona type ion generating element 27 is not particularly limited,
The electric field strength is preferably 100 V / cm or higher. When the electric field strength is less than 100 V / cm, the substantial electrification amount becomes small, and a sufficient electret effect cannot be obtained. Further, a DC corona ion generating element in which corona discharge occurs in both the counter electrode and the discharge electrode (bipolar corona) can be used, but the DC corona ion that can generate the single polar ion described above is also usable. The generating element has higher charging efficiency.

According to the above charging mode, the filter 11
Is sufficiently charged, the discharge is stopped and the electretization process of the filter, that is, the charging mode is ended. Then, if necessary, the DC corona type ion generating elements 26 and 27 are moved away from the flow path of the gas to be processed, converted to the ventilation mode, and the gas to be processed containing dust is passed through the electretized filter 11. Then, the dust included in the gas to be treated is collected by the filter 11 by the electrostatic attraction, and the gas to be treated can be purified. During the purification process of the gas to be treated, it is not necessary to apply a voltage, and the electretization process can be completed in a short time, so the power consumption required for charging the filter can be suppressed and the amount of ozone generated can be reduced. Can be lowered. Electretized filter 1
In No. 1, the effect of the electret deteriorates when it is used for a long period of time, so that the dust collection efficiency decreases with time as compared with the sufficient dust collection efficiency immediately after the electret treatment. In this case, the ventilation mode is interrupted, the charging mode is replaced again, and the electretization process of the filter is repeated again, whereby sufficient dust collection efficiency can be recovered. The device of the present invention can be operated while switching between the charging mode and the ventilation mode. Further, since the electretization process can be completed in a short time, it is possible to operate while switching between the charging ventilation mode and the ventilation mode without stopping the gas purification process.

In the present invention, an AC corona type ion generating element can be further used as the ion generating means, and a typical mode in which the AC corona type ion generating elements are respectively used as the pair of ion generating means is shown in FIG. Shown in.
In this mode, two AC corona type ion generating elements 28 and 29 are arranged to face each other with a predetermined space therebetween. Each of the AC corona type ion generating elements 28 and 29 includes an inducing electrode 88a and 89a and a discharge electrode 88b and 8 respectively.
9b, inducing electrodes 88a, 89a and discharge electrode 88
b and 89b are connected to AC power supplies 68 and 69, respectively. In this embodiment, each induction electrode 88a, 89a
Are connected to DC power supplies 78 and 79, respectively. Generally, the AC power supplies 68 and 69 are composed of an AC generator and a transformer,
The DC power supplies 78 and 79 can be connected from the secondary side ground terminal of the transformer. The AC corona type ion generating elements 28 and 29 shown in FIG. 10 each have five inductive electrodes 88a and 89a and four discharge electrodes 88b and 89b, but the number of electrodes is changed according to the environment or purpose of use. can do. The induction electrodes 88a and 89a are
As shown in FIG. 10, it is preferable to coat the dielectric 38, 39 such as glass, ceramic, or plastic. This is because spark discharge can be prevented and stable corona discharge can be performed.

Two AC corona type ion generating elements 28,
When the filter 11 is arranged between 29 and those elements in a non-contact state and an AC high voltage is applied from the AC power sources 68 and 69, the discharge electrodes 88b and 89b and the induction electrodes 88a and 8a.
Both ions of positive polarity and negative ions are generated between the positive electrode and the negative electrode 9a. At this time, if DC voltages V21 and V22 of different potentials are simultaneously applied from the DC power supplies 78 and 79, DC voltage is applied between the AC corona type ion generating elements 28 and 29 as in the case of the AC creeping discharge element described above. A boundary is formed. When a charging electric field is formed between the AC corona-type ion generating elements 28 and 29, the induction electrodes 88a and 89a and the discharge electrodes 88b and 89b are ion attracted to the AC corona-type ion generating elements 29 and 28 facing each other. Acts as a sex electrode.

For example, when a positive voltage V22 is applied to the DC power supply 79, only the negative ions out of the positive and negative ions generated in the AC corona type ion generating element 28 of the AC corona type ion generating element 29. It is selectively attracted to the induction electrode 89a and the discharge electrode 89b set to a positive potential, moves toward the AC corona type ion generating element 29, and adheres to the gas inflow surface of the filter 11 arranged in the middle thereof. , Charge the gas inlet surface of the filter. On the other hand, of the positive and negative ions generated in the AC corona-type ion generating element 29, only the positive-polarity ions are applied to the induction electrode 88a and the discharge electrode 88b which are set to the negative potential of the AC corona-type ion generating element 28. Selectively sucked,
It moves in the direction of the AC corona type ion generating element 28, adheres to the gas outflow surface of the filter 11 disposed in the middle thereof, and charges the gas outflow surface of the filter. Thus, the filter 11 is simultaneously treated with positive ions from one and negative ions from the other.

The high frequency AC voltage applied to generate the AC corona discharge by the AC power source is not particularly limited, but is preferably about 0.1 KVp-p to 50K.
Vp-p (KVp-p indicates the voltage difference from the maximum value peak to the minimum value peak of the AC voltage), and the frequency is not particularly limited, but preferably 0.1 to 100.
KHz. When the voltage is less than 0.1 KVp-p, the discharge does not substantially occur, and when the frequency is less than 0.1 KHz, an extremely large voltage is required for the discharge.
If the frequency exceeds 0 KHz, there is a problem that the dielectric material may be overheated due to dielectric heating and may be destroyed. The distance between the induction electrode and the discharge electrode capable of causing AC corona discharge is preferably about 0.1 mm to 10 mm. The electric field strength applied to the induction electrodes 88a and 89a is not particularly limited, but is preferably 100 V / cm or more, more preferably 500 V / cm or more. Electric field strength is 100
When it is less than V / cm, a substantial electrification amount becomes small, so that a sufficient electret effect cannot be obtained.

According to the above charging mode, the filter 11
Is sufficiently charged, the discharge is stopped and the electretization process of the filter, that is, the charging mode is ended. Then, if necessary, the AC corona ion generating elements 28 and 29 are moved away from the flow path of the gas to be processed, converted into the ventilation mode, and the gas to be processed containing dust is passed through the electretized filter 11. Then, the dust included in the gas to be treated is collected by the filter 11 by the electrostatic attraction, and the gas to be treated can be purified. During the purification process of the gas to be treated, it is not necessary to apply a voltage, and the electretization process can be completed in a short time, so the power consumption required for charging the filter can be suppressed and the amount of ozone generated can be reduced. Can be lowered. Electretized filter 1
In No. 1, the effect of the electret deteriorates when it is used for a long period of time, so that the dust collection efficiency decreases with time as compared with the sufficient dust collection efficiency immediately after the electret treatment. In this case, the ventilation mode is interrupted, the charging mode is replaced again, and the electretization process of the filter is repeated again, whereby sufficient dust collection efficiency can be recovered. The device of the present invention can be operated while switching between the charging mode and the ventilation mode. Further, since the electretization process can be completed in a short time, it is possible to operate while switching between the charging ventilation mode and the ventilation mode without stopping the gas purification process.

In addition to the above combinations shown in FIGS. 2, 6, 7, 8, 9 and 10, the present invention provides a combination of an AC creeping discharge element and an ionizer element, and an AC creeping element. A combination of a discharge element and a DC corona type ion generation element,
Combination of AC creeping discharge element and AC corona type ion generating element, combination of ionizer element and DC corona type ion generating element, combination of ionizer element and AC corona type ion generating element, or DC corona type ion generating element and AC It can also be implemented in combination with a corona type ion generating element. The air filter device of the present invention,
For example, it can be used in an air cleaner or a dust collector, but is limited to a mode in which a filter medium, a pair of ion generating means, and a pair of ion attracting electrodes are integrally provided so that they can be arranged or removed collectively. Not something
It can also be provided so that each can be placed or removed separately. It is preferable that the pair of ion generators and the pair of ion attracting electrodes are arranged in an air cleaner or a dust collector, and only the filter medium is exchangeably provided in the air cleaner or the dust collector. In the present invention, since it is not necessary to bring the filter medium into contact with the ion generating means or the ion attracting electrode, the filter medium having substantially any shape, for example, a flat plate filter,
A pleated filter or the like can be used. In addition, since the distance between the filter medium and the ion generating means or the ion attracting electrode can be widened, the filter medium can be easily replaced.

The filter material that can be used in the air filter device of the present invention is not particularly limited as long as it is made of a chargeable material, and a molded body made of any conventionally known filter material, for example, a fiber material is used. Can be any molded body. For example, as the fibrous body, a non-woven fabric such as a dry non-woven fabric, a spunbonded non-woven fabric, a melt blown non-woven fabric, a hydroentangled non-woven fabric, a wet non-woven fabric, a fabric such as a woven fabric or a knitted fabric, paper, a fibrous porous film, or a composite thereof is used. A fiber sheet can be mentioned. In particular, a fiber sheet such as a melt blown non-woven fabric or a hydroentangled non-woven fabric which does not have a fiber oil agent or an adhesive attached thereto is preferable because it is easily electretized. Further, as the fibrous body, a three-dimensional one such as one obtained by processing the above-mentioned fibrous sheet into a corrugated plate shape or a zigzag shape can be preferably used.

Examples of fibers constituting these fibrous bodies include dielectric fibers such as polyolefins such as polyethylene and polypropylene, polyesters, polycarbonates, polyvinyl chloride and the like.
The specific resistance of these fibers is preferably 10 ¹² Ωcm or more, more preferably 10 ¹⁴ Ωcm or more. 10 ¹² Ω
If it is less than cm, the leakage of the charge is too early, the charge life is remarkably short, and the dust collection efficiency is largely deteriorated with time.
In the conventional electret filter, it was difficult to use a material having a short charge life even if the material has a large amount of charge, whereas as a fibrous body that can be used in the air filter device of the present invention, A material having a large charge amount can be used even if the charge life is somewhat short.

[0044]

The present invention will be described in detail below with reference to examples, but these do not limit the scope of the present invention. Example 1 A filter having a fabric weight of 45 g / m ² and a thickness of 0.7 m
m polypropylene melt-blown nonwoven fabric was used. The filter 11 was charged using an air filter device that performs the charging mode in the arrangement shown in FIG. 11. In the air filter device of the present invention shown in FIG. 11,
Two AC creeping discharge elements shown in FIG. 5 are arranged at intervals such that the distance between the discharge electrodes of the facing creeping discharge elements is 40 mm, and the discharge electrodes 41, 42 in each AC creeping discharge element 21, 22 are arranged. The induction electrodes 51 and 52 were connected to AC power supplies 61 and 62, respectively, and the discharge electrodes 41 and 42 were connected to DC power supplies 71 and 72, respectively. The filter 11 is passed between the creeping discharge device 21 and the creeping discharge device 22, and an alternating current having a voltage of 6 KVp-p and a frequency of 23 KHz is applied to generate a creeping discharge in each creeping discharge device, and a potential difference between discharge electrodes. Was set to 10 KV and the filter 11 was charged for 1 minute. After carrying out the charging mode, atmospheric dust was passed through the obtained electretized melt-blown non-woven fabric at a surface wind velocity of 5 cm / sec,
The initial pressure loss and the efficiency of collecting atmospheric dust of 0.3 to 0.5 μm were obtained. The measurement is carried out 5 times, and the respective results are shown by showing the minimum value and the maximum value of the measured values of 5 times. The collection efficiency was about 0 before and after passing through the meltblown nonwoven fabric.
The number of particles of 3 to 0.5 μm was measured by a particle counter and determined. Initial pressure loss is 1.1 to 1.5 mma
At q, the collection efficiency was 90-95%.

Example 2 An electretized meltblown nonwoven fabric was obtained by repeating the procedure of Example 1 except that the distance between the discharge electrodes of the opposing surface discharge elements was 120 mm. Using the obtained electretized meltblown nonwoven fabric, the aeration operation of Example 1 was repeated to obtain an initial pressure loss of 0.3 to 0.5 μm.
m air dust collection efficiency was determined. Measurement is performed 5 times,
The respective results are shown by showing the minimum value and the maximum value of the measured values of 5 times. The initial pressure loss of the obtained electret melt-blown nonwoven fabric is 1.1 to 1.5 mmaq.
The collection efficiency was 90 to 95%. It was found that even if the distance between the electrodes is widened, the electret can be formed as in Example 1.

Example 3 A filter having a basis weight of 240 g / m ² comprising 80% by weight of polypropylene fiber and 20% by weight of rayon fiber,
And a needle punched nonwoven fabric having a thickness of 1.5 mm was used.
The filter 11 was charged using an air filter device that performs the charging mode in the arrangement shown in FIG. 11.
Set the distance between the discharge electrodes of the creeping discharge elements 21, 22 facing each other to 1
It was set to 20 mm. The filter 11 is connected to the creeping discharge element 2
1 and the creeping discharge element 22 through a voltage of 6 KVp-
A creeping discharge was generated in each creeping discharge element by applying an alternating current of p and a frequency of 23 KHz, the potential difference between the discharge electrodes was set to 15 KV, and the filter 11 was charged for 1 minute. After the end of the charging mode, the electretized needle punched nonwoven fabric was exposed to atmospheric dust at a surface wind velocity of 5c.
The initial pressure loss and 0.3-
An air dust collection efficiency of 0.5 μm was determined. The measurement is carried out 5 times, and the respective results are shown by showing the minimum value and the maximum value of the measured values of 5 times. The collection efficiency was determined by measuring the number of particles of 0.3 to 0.5 μm before and after passing through the needle punched nonwoven fabric with a particle counter. The initial pressure loss is 1.0 to 1.3 mmaq and the collection efficiency is 90.
Was ~ 96%.

Example 4 A polypropylene melt-blown non-woven fabric having a basis weight of 45 g / m ² and a polyester fiber web bonded with a binder containing an acrylic-vinyl chloride copolymer as a main component to prepare a binder having a basis weight of 50 g / m ² . The bonded non-woven fabric was pleated under the conditions of a depth of 20 mm and a pitch of 10 mm to obtain a pleated filter. This pleated filter 11 was arranged as shown in FIG. 6 together with a pair of flat plate AC surface discharge elements 21 and 22 to obtain an air filter device. AC creeping discharge elements 21, 22
The shortest distance was set to 28 cm. While passing air (atmosphere) through the filter, it was charged for 30 seconds in the charging ventilation mode. The charging was performed by applying a voltage of 6 KVp-p and an alternating current having a frequency of 20 KHz to generate a creeping discharge in each creeping discharge element and set the potential difference between the discharge electrodes to 20 KV. Further, the flow rate of air was set so that the filtration rate in the filter was 5 cm / sec. Included in the air before and after passing through the filter.
When the collection efficiency was obtained by measuring the number of atmospheric dust of 3 to 0.5 μm with a particle counter, it was 30 to 3 before charging.
While it was 5%, it was 96 to 98% immediately after the termination of the charging and aeration mode for 30 seconds, which was a very excellent collection ability. After 8 hours of ventilation, after 12 hours of rest, the collection efficiency when re-vented was slightly reduced to 90-93%, but when charged again under the same conditions, it was 96 immediately after the termination of the charging ventilation mode for 30 seconds. The collection ability recovered to ~ 98%.

Example 5 The pleated filter used in Example 4 was arranged as shown in FIG. 2 together with the rod-shaped AC creeping discharge elements 21 and 22 as shown in FIG. 3 to obtain an air filter device. However, the number of each AC creeping discharge element 21, 22 is the same as the filter 1
The number was set to 5 before and after 1, and set so that the shortest distance between the AC surface discharge elements 21 and 22 facing each other was 15 cm. The diameter of each AC creeping discharge element was 10 mm. While passing air (atmosphere) through the filter, it was charged for 30 seconds in the charging ventilation mode. The charging was performed by applying a voltage of 6 KVp-p and an alternating current with a frequency of 20 KHz to generate a creeping discharge in each creeping discharge element and to set the potential difference between the discharge electrodes to 11 KV. Further, the flow rate of air was set so that the passing speed through the filter was 5 cm / sec. When the collection efficiency was calculated by measuring the number of 0.3-0.5 μm atmospheric dust contained in the air before and after passing through the filter with a particle counter, it was 30-35% before charging. On the other hand, 96 to 98 immediately after the end of the charging ventilation mode for 30 seconds.
As a result, it showed a very good collection ability as a percentage. After ventilation for 8 hours, 1
The collection efficiency is 90 to 9 after a 2-hour pause and aeration.
Although it was slightly decreased to 3%, when it was charged again under the same conditions, it was 96-
The collection ability has recovered to 98%.

[0049]

According to the present invention, the charged state of the filter medium can be maintained only by performing a short-time charging process as necessary (preferably, periodically), and therefore, compared with the conventional electrostatic precipitator. As a result, the power consumption in the charging process can be suppressed and the ozone generation amount can be reduced. Further, the dust collection efficiency is higher than that of the conventional dielectric filter. Further, in the conventional electret filter, it was necessary to replace the filter every time the dust collection efficiency was lowered, but the air filter device of the present invention does not require it and the dust collection efficiency is high. Further, according to the present invention, the charge amount of the filter does not depend on the electric field strength between the ion attracting electrodes but depends only on the potential difference between the ion attracting electrodes. Even when a high charging voltage is applied between the electrodes, there is no risk of spark discharge between the ion-attracting electrodes. Moreover, since the space between the ion-attracting electrodes can be made sufficiently wide, the shape of the filter medium is not limited. For example, a non-flat plate-shaped or pleated filter can be used, and the filter medium can be easily replaced. You can

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing a conventional air filter device.

FIG. 2 is a perspective view schematically showing one embodiment of the device of the present invention using a pair of columnar AC creeping discharge elements.

FIG. 3 is a perspective view of a columnar AC creeping discharge element used in the device shown in FIG.

4 is a graph showing an AC waveform obtained when an AC voltage and a DC voltage are applied using the device shown in FIG.

FIG. 5 is a perspective view of a flat plate AC creeping discharge element that can be used in the device of the present invention.

6 is a perspective view schematically showing another aspect of the device of the present invention using the pair of flat plate AC surface discharge elements shown in FIG.

FIG. 7 is a cross-sectional view schematically showing one embodiment of the device of the present invention using a pair of cylindrical AC surface discharge elements.

FIG. 8 is a cross-sectional view schematically showing one embodiment of the device of the present invention using a pair of ionizers.

FIG. 9 is a cross-sectional view schematically showing an embodiment of the device of the present invention using a pair of DC corona type ion generating elements.

FIG. 10 is a cross-sectional view schematically showing one embodiment of the device of the present invention using a pair of AC corona type ion generating elements.

11 is a cross-sectional view schematically showing another aspect of the device of the present invention using the pair of flat plate AC surface discharge elements shown in FIG.

[Explanation of symbols]

1 ... Counter electrode; 2 ... Discharge electrode; 3 ... Preliminary charging part; 4 ...
・ Parallel plate electrode; 5 ・ ・ Fibrous body; 6 ・ ・ Electrode; 11 ・
・ Processing object; 12 ・ ・ Intake air gap; 13 ・ ・ Exhaust air gap; 2
1, 22 ··· AC creeping discharge element; 24, 25 · · Ionizer; 26, 27 · · DC corona type ion generating element;
28,29 ... AC corona type ion generating element; 31,3
2,38,39 ... Dielectrics; 41,42,86b, 87
b, 88b, 89b ··· discharge electrode; 44, 45 · · ion attracting electrode; 51, 52, 88a, 89a · · induction electrode;
61, 62, 68, 69 ... AC power supply; 71, 72, 7
4a, 75a, 76a, 76b, 77a, 77b, 7
DC power supplies 84a, 85a .. Corona discharge electrodes; 84b, 85b ..
Earth pole; 84c, 85c ... Guide plate; 86a, 87
a ... Counter electrode.

Claims (6)

(57) [Claims] 1. A filter medium comprising (1) a chargeable material, (2) first ion generating means for generating positive and / or negative ions, and positive and negative ions. A pair of ion generating means composed of second ion generating means for generating both or the other; (3) When both positive and negative ions are generated in the first ion generating means, any one of them When a positive ion or a negative ion is generated in the first ion generating means, the first ion attracting electrode for attracting the generated ion, and the second ion generating When both positive and negative ions are generated in the means, either one of them is selectively sucked, and either the positive ion or the negative ion is generated in the second ion generating means. In this case, the charge-type air filter device includes a pair of attracting electrodes composed of a second ion attracting electrode that attracts the generated ions, wherein at least when the filter medium is charged: ) A filter medium is disposed between the first ion generating means and the second ion generating means arranged opposite to each other in a non-contact state with these, and (b) the filter medium is viewed from the first ion generating means. A first ion-attracting electrode is disposed on the other side of the electrode, and when both positive and negative ions are generated in the first ion generating means, any one of them is selectively used as a filter medium. When one of the positive ion and the negative ion is generated in the first ion generating means, the generated ion is moved to the filter medium, and (c) is viewed from the second ion generating means. The above filter material When a second ion-attracting electrode is arranged on the other side and both the positive and negative ions are generated in the second ion generating means, the first ion generating means is used as a filter medium. When only ions having the opposite polarity to the moved ions are selectively moved to the filter medium and either the positive ion or the negative ion is generated in the second ion generating means, the first ion is generated. The generated ions are transferred to the filter medium with the opposite polarity to the ions transferred from the ion generating means to the filter medium, and the ions transferred to the filter medium from the first ion generating means and the second ion A charged air filter device characterized in that the inflow surface and outflow surface of the gas to be treated in the filter medium are charged by the ions transferred from the ion generating means to the filter medium. 2. The first ion generating means and the second ion generating means each independently of a group consisting of an AC creeping discharge element, an ionizer element, a DC corona type ion generating element, and an AC corona type ion generating element. The charged air filter device according to claim 1, which is a selected ion generating means. 3. The first ion generating means and the second ion generating means are both AC creeping discharge elements which generate both positive and negative ions, and the first ion generating means. Of the first ion generating means by applying different direct-current potentials to the AC creeping discharge element as an element and the AC creeping discharge element as the second ion generating element to form a DC electric field between them. Acts as a second ion attracting electrode and attracts only one of the positive ion and the negative ion, and similarly, the second ion generating means functions as the first ion attracting electrode. The charged air filter device according to claim 1 or 2, which acts to attract ions having a polarity opposite to that of the ions attracted by the second ion attracting electrode. 4. The first ion generating means is an ionizer element for generating positive ions, the second ion generating means is an ionizer element for generating negative ions, and the first ion attracting electrode is the positive electrode. The charge-type air filter device according to claim 1, wherein the charge-type air filter device is an electrode that attracts negative ions, and the second ion-attractive electrode is an electrode that attracts negative ions. 5. The first ion generating means is a direct current corona type ion generating element for generating positive polarity ions, and the second ion generating means is a direct current corona type ion generating element for generating negative polarity ions. Different direct current potentials are applied to the direct current corona type ion generating element as the first ion generating means and the direct current corona type ion generating element as the second ion generating means to form a direct current electric field between them. As a result, the first ion generating means is
2. The second ion generating means acts as a first ion-attracting electrode to attract positive-polarity ions by acting as an ion-attracting electrode to attract negative-polarity ions. Or the charge-type air filter device according to item 2. 6. The first ion generating means and the second ion generating means are both AC corona type ion generating elements for generating both positive and negative ions, and the first ion By applying different DC potentials to the AC corona type ion generating element as the generating means and the AC corona type ion generating element as the second ion generating means,
By forming a direct current electric field between them, the first ion generating means acts as the second ion attracting electrode to attract only one of the positive ion and the negative ion. The second ion generating means acts as a first ion-attracting electrode to attract ions having a polarity opposite to that of the ions attracted by the second ion-attracting electrode. 2. The charge-type air filter device according to item 2.