JP2005216763A - Ionization airflow generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a safe static eliminator improved in problems of a service life and efficiency of a conventional corona discharge type static eliminator; an ionization device; and an ionization airflow generator suitable for an ozonizer as well. <P>SOLUTION: This ionization airflow generator comprises: a dielectric tube 1; an inner electrode 2 inserted into the dielectric tube; a thin-wire conductor 4 adjacent to the dielectric tube and installed so as to surround the dielectric tube; an outer tube 3 installed so as to surround the dielectric tube and the thin-wire conductor; an introduction port 5 of a gas to a space between the dielectric tube 1 and the outer tube 3; and an exhaust port 6 of the gas to the outside. The ionization airflow generator is characteristically structured to generate dielectric barrier discharge between the thin-wire conductor 4 and the inner electrode 2 through the dielectric tube by applying a voltage between the inner electrode 2 and the thin-wire conductor 4, and an airflow entraining generated ions is discharged to the outside. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an ionized airflow generator used as, for example, a static eliminator or an ionizer.

  Static electricity that accumulates on the surface of insulators (dielectrics) such as plastic often causes discomfort to the human body, as well as dust adsorption, fire occurrence due to discharge, printing, coating, vacuum deposition, sputtering, etc. It is a cause of great obstacles in the living environment and industrial processes, such as unevenness in surface treatment and unevenness of photographic film, and there is a great need for removal, that is, neutralization.

Conventionally, the most widely used static eliminator is a corona discharge method using a needle-like electrode, but this method uses the tip of the needle-like electrode to wear due to the continuation of the corona discharge, and is used for about 10,000 hours. There is a basic problem that the processing capacity decreases rapidly if the process is continued. In order to alleviate the problem of electrode wear in the corona discharge type static eliminator using such a needle electrode, a static eliminator using a wire electrode has also been proposed. The concentration of the electric field does not occur as much, and it is difficult to realize an efficient corona discharge because it is difficult to form a high electric field.
Izumi Hayashi, “High Voltage Plasma Engineering”, p. 35, published by Maruzen Co., Ltd. (1996). Sachiko Okazaki et al. “Atmospheric pressure glow discharge and plasma technology”, Industrial Technology, Vol. 27, no. 1, pages 5-16.

  A main object of the present invention is to provide a corona discharge type ionized airflow generator that can be suitably used as a static elimination device that has improved the life and efficiency problems of a conventional corona discharge type static elimination device.

  That is, the present invention includes a dielectric tube, an inner electrode inserted in the dielectric tube, a thin wire conductor disposed so as to be adjacent to and surround the dielectric tube, An outer cylinder disposed so as to surround the dielectric tube and the thin wire conductor, a gas inlet to a gap between the dielectric tube and the outer cylinder, and a gas outlet to the outside; By applying a voltage between the electrode and the thin wire conductor, a dielectric barrier discharge is caused between the thin wire conductor and the inner electrode via the dielectric tube, and an air flow accompanied by the generated ions is released to the outside. It is an object of the present invention to provide an ionized airflow generator characterized by being configured.

  Preferably, the outer cylinder constitutes an outer cylinder electrode made of a conductive metal, and is disposed so as to be in electrical contact with the thin wire conductor, thereby applying a voltage between the inner electrode and the outer cylinder electrode. Thus, power is supplied to the fine wire conductor via the outer cylindrical electrode, and a dielectric barrier discharge is generated between the fine wire conductor and the inner electrode via the dielectric tube. Preferably, the fine wire conductor is a metal fine wire (wire), and is wound around the outer periphery of the dielectric tube in a coil shape at an appropriate interval. The outer cylinder or the outer cylinder electrode is provided with a slit shape or a plurality of gas outlets along the longitudinal direction thereof.

  In the ionized airflow generator of the present invention, the thin wire conductor (metal thin wire) that acts as the counter electrode of the inner electrode through the dielectric is disposed very close to the dielectric, so that it is stable between the inner electrode and the inner electrode. It is possible to generate a high electric field. For this reason, a stable corona discharge by a low-current dielectric barrier discharge (that is, a gas discharge (barrier discharge) that occurs on the surface of the dielectric covering at least one of the pair of electrodes; Non-Patent Document 1) becomes possible. Efficient ionization of the airflow passing through the contact becomes possible.

  Hereinafter, the ionized airflow generator of the present invention will be described more specifically based on examples.

(Example 1)
FIG. 1 is a partially cutaway schematic cross-sectional view in the longitudinal direction of a tubular ionized airflow generator according to an embodiment of the present invention configured as a static eliminator, and FIG. 2 is a schematic cross-sectional view in the direction of arrows II-II in FIG. FIG.

  Referring to FIGS. 1 and 2, an ionized airflow generator of this example includes a dielectric tube 1 (for example, a quartz glass tube (outer diameter: 5 mmφ, thickness: 1.0 mm, length: about 300 mm) sealed at one end. ) And the inner electrode 2 inserted into the dielectric tube 1 (excluding the coating of the silicone resin-coated electric wire, the outer diameter is about 1.6 mm with 26 stranded wires of 0.2 mm copper core wire) The outer tube electrode 3 (brass thin tube (outer diameter: about 8 mmφ, thickness: about 0.5 mm)) as an outer tube surrounding the dielectric tube 1, the dielectric tube 1 and the outer tube electrode 3 And a coiled wire electrode 4 (0.2 mmφ tungsten wire or SUS wire) as a thin wire conductor which is wound around the dielectric tube 1 and arranged so as to be in contact with the outer cylinder electrode 3. Further, one end of the outer tube electrode 3 on the side of the sealed one end of the dielectric tube 1 has an opening 5 functioning as a gas inlet, and the outer tube electrode 3 has an appropriate length in the lower side in the longitudinal direction. A plurality of gas discharge ports 4 (diameter: about 1.5 mmφ) are provided at intervals (for example, about 10 mm), and the base portion opposite to the opening 5 of the outer cylindrical electrode 3 is the base portion of the dielectric tube 1 and the inner electrode 2. In addition, the resin mold 7 is fixed together with the coating 2 a of the inner electrode 2. Further, the inner electrode 2 and the outer cylinder electrode 3 are connected to an AC power source 8 (for example, a voltage boosted from a household power source to supply a voltage of 9 kV and 60 Hz) via the switch 9 so that an AC voltage can be applied. Has been. Further, the outer cylinder electrode 3 is grounded and exposed (of course, resin coating or the like may be appropriately performed), and consideration is given to safety.

In an example of operation, compressed air (about 0.15 kg) from the opening 5 using a rotary pump (“DRB-35” manufactured by Yasunaga Iron Works Co., Ltd .; not shown) for the apparatus having the above-described exemplary dimensions. / Cm ² · G) is introduced at a rate of about 25 to 30 liters / minute, an AC voltage is applied from the power source 8, and an air flow accompanied by alternating ions of positive and negative signs is provided every half cycle of the AC. 6 was discharged. Then, this ionized air flow is preliminarily rubbed with a cotton cloth to be charged to about −2 to −3 kV (measured by “FMX-002 type” static electricity measuring device manufactured by SIMCO) and separated from the lower part of the apparatus of FIG. When sprayed instantaneously (less than 1 second) on a polyethylene terephthalate (PET) film of about 50 mm × 100 mm placed on the surface, the surface potential was almost zero V, and the charge was substantially completely eliminated.

(Example 2)
The apparatus of Example 1 was used, except that a 2 kV DC power supply (not shown) was connected in series with the AC power supply 8 instead of the positive and negative balanced complete AC power supply 8 (9 kV, 60 Hz). The outer cylinder electrode 3 side was connected so as to be a negative electrode, a DC superimposed AC voltage was applied, an ionized air stream rich in negative ions blown out from the hole 6 was discharged, and sprayed onto a substantially uncharged PET film. As a result, a surface potential of about −100 to −200 V was uniformly observed on the treated PET film.

(Example 3)
As in Example 2, except that a 2 kV DC power supply is now reversed in polarity and connected in series with an AC power supply 8 (9 kV, 60 Hz) so that the outer cylinder electrode 3 side is positive. Was applied, and the ionized air stream rich in positive ions blown out from the holes 6 was discharged, and sprayed onto a substantially uncharged PET film. As a result, a surface potential of about +100 to +200 V was uniformly observed on the treated PET film.

(Modification)
In the said Examples 1-3, the specific Example of the ionization airflow generator of this invention which functions as a static elimination apparatus and an ionization apparatus was shown. However, such an embodiment is merely an example, and various modifications are possible within the scope of the present invention. In particular, it is obvious to those skilled in the art that the dimensions of the respective parts described in the above embodiments can be changed greatly depending on the object to be processed, and the material can be changed as appropriate.

For example, prior to the first embodiment, as compared with the case where about 8 liters / minute of air is sent as a smaller air volume from the opening 5, the amount is increased to about 25-30 liters / minute as in the first embodiment. A better static elimination effect has been confirmed. It will of course be understood that larger volumes of air can be delivered depending on the object to be treated, and possibly multiple parallel use of the device. Further, in the first embodiment, since household electricity was used, the frequency of the AC power supply 8 was relatively low at 60 Hz. However, by applying a high frequency AC voltage of 1 to 10 kHz or more, higher speed static elimination and ionization are possible. It will be obvious to those skilled in the art that processing is possible. The voltage applied by the power supply 8 is not limited to 9 kV in the above example, and generally a voltage of about 1 to 20 kV that can ensure insulation relatively safely is suitably used.

  Furthermore, according to the knowledge of the present inventor, the following modifications are possible.

  (1) In the above example, when a voltage is applied between the fine wire conductor 4 and the inner electrode 2, power is supplied to the fine wire conductor 4 via the metal outer cylinder electrode 3. This configuration is a preferable mode for preventing a voltage drop due to the resistance of the thin wire conductor 4 in the longitudinal direction of the apparatus and forming a uniform voltage distribution (potential), and requires electrical continuity of the thin wire conductor 4 itself. Although there is an advantage that it may not be cut (may be cut off in the middle), power can be directly supplied to the thin wire conductor 4 without going through the outer cylinder 3. In this case, the outer cylinder 3 may be made of resin. Also, in this case, in order to prevent a voltage drop in the longitudinal direction of the apparatus, the thin wire conductor 4 is not a coil electrode, but a mesh electrode (or a lap winding of two coil conductors whose spiral winding directions are opposite to each other). It is preferable to provide a ring-shaped terminal at at least one of both ends in the longitudinal direction to improve the power supply to the thin wire conductor 4.

  (2) The type of voltage applied between the thin wire conductor 4 and the inner electrode 2 may be a direct current or an alternating pulse voltage.

  (3) The thin wire conductor 4 is not limited to a metal wire, and may be a thin wire of any conductor such as a carbon wire.

  Further, the outer diameter of the thin wire conductor is preferably thinner in order to secure a high electric field. In the above example, the outer diameter is set to 0.2 mm. It can be appropriately selected from a range of about 8 mm.

  (4) The apparatus shown in FIGS. 1 and 2 can be summarized as shown in FIG. 3 (FIG. 3 (a) is equivalent to FIG. 2, (b) is equivalent to FIG. 1). In order to increase the flow rate of the ionized airflow, an airflow pipe 3a (FIG. 4) separate from the outer electrode pipe 3 can be provided, or an airflow pipe 3b (FIG. 5) obtained by expanding the airflow pipe can be provided. .

  (5) In the apparatus, as long as the gas flow between the dielectric tube 1 and the outer cylinder electrode 3 is ensured, the arrangement of the gas introduction port 5 and the discharge port 6 has various options. . For example, the following modifications are possible.

  (A) In the embodiment shown in FIGS. 1 and 2 (therefore, FIG. 3), a plurality of small holes are provided at intervals on the lower side of the outer tube electrode tube 3 in the figure. It can also be provided over the entire circumference of the electrode tube. This is suitable, for example, when the ionized air stream is efficiently distributed from the outer tube electrode tube to the surrounding medium (for example, air or insulating liquid). Further, instead of the plurality of small holes arranged in a line as used in the above example, a slit-like opening extending along the longitudinal direction of the outer cylinder 3 (for example, a groove width of 1.5 mm and a length in Example 1 above) On the other hand, it has also been confirmed that the flow of the ionized airflow is improved and the static elimination effect is improved.

(B) Further, as shown in FIG. 6 corresponding to FIG. 3B, if the jacket tube 10 is provided so as to surround the outer tube electrode tube 3 and gas is introduced from the opening 5a, the gas outlet 6 in the above example. The small hole that acted as the gas inlet port into the outer tube electrode 3 is used, and in the above example, the opening that acted as the gas inlet port 5 is used as the gas outlet 6a for discharging the ionized gas flow. Further, this gas inlet may be provided in the resin mold portion 7 at the end opposite to the opening 6a without providing the jacket tube 10 (and the openings 5a and 5b). At this time, the gas inlet may be configured to introduce a swirl flow into the outer electrode tube as a spiral hole. However, in the configuration in which the ionized airflow is discharged from one end of the outer electrode tube 3 as in this example, the distance from the gas ionization portion (the gap between the wire 4 and the dielectric tube 1) to the airflow outlet 6a increases. However, the ions generated in the middle give useful changes to the working gas (for example, when air is used as the working gas, an air flow rich in ozone (O ₃ ) This can be interpreted as a function similar to that of the ozonizer disclosed on pages 14 to 15 of Non-Patent Document 2. In this case, the exhaust airflow can be used effectively. As described above, the “ionized airflow generator” of the present invention includes an apparatus (for example, an ozonizer) in which an ionized airflow is generated in the apparatus, but ions are reduced in the airflow discharged from the apparatus. Is. For example, in the case of configuring an ozonizer, the ozone-rich air flow discharged from the discharge port 6a is preferably used for ozone treatment such as drainage.

  (6) In the above description, air is mainly used as the working gas. However, any gas that can be ionized by corona discharge (dielectric barrier discharge) is used as the working gas.

  (7) An air flow rich in negative ions discharged from the outlet 6 of the second embodiment is considered favorable for environmental health to the human body, and therefore the apparatus of the second embodiment can also be used as a negative ion generator. Of course.

  (8) The dielectric tube 1 and the outer cylinder 3 do not have to be perfect circles, and in particular, the surface of the outer cylinder 3 facing the object to be processed should be wide or flat (as a result, the cross section becomes a horseshoe shape). May be preferable for discharging the ionized air flow and improving the processing efficiency.

  (9) The dielectric tube 1 is not limited to quartz, but is generally made of a ceramic dielectric. However, as thin as the strength permits, the thinner one is advantageous for generating a high electric field. The upper limit can be appropriately selected from a range of about 7 mm or less to about 3 mm.

  (10) The inner electrode 2 is not limited to the stranded wire in the above example, and a relatively thick conductor single wire is also used. The inner electrode 2 is preferably as close as possible to the dielectric tube 1 as long as it can be inserted into the dielectric tube 1. Therefore, the inner electrode 2 can also be formed as a metal electrode deposited inside the dielectric tube 1. is there.

  As described above, according to the present invention, there is provided an ionization airflow generator that is improved as a lifetime and efficiency problem of a conventional corona discharge static eliminator, and that is also suitable as an ionizer and an ozonizer. . As is clear from the above embodiments, this device can be configured extremely compactly, and can be handled extremely safely even when using high voltages by grounding the outer cylinder (electrode) or thin wire conductor. is there.

The longitudinal direction partial notch schematic cross section of the tubular ionization airflow generator which concerns on one Example of this invention comprised as a static elimination apparatus. FIG. 2 is a schematic cross-sectional view taken along the line II-II in FIG. 1. The aggregation schematic diagram of FIG. 1 and FIG. FIG. 4 is a schematic diagram showing a modification of the apparatus in FIG. 3. FIG. 4 is a schematic diagram showing a modification of the apparatus in FIG. 3. The schematic diagram which shows the deformation | transformation arrangement example of a gas inlet and an outlet.

Explanation of symbols

1 Dielectric (quartz glass) tube 2 Inner electrode (high voltage silicone rubber coated copper wire)
2a Inner electrode coating 3 Outer cylinder (electrode)
3a, 3b Gas flow tube 4 Fine wire conductor (coiled wire electrode)
5, 5a, 5b Gas inlet 6, 6a Gas outlet 7 Resin mold 8 (AC) power supply 9 Switch

Claims (7)

A dielectric tube, an inner electrode inserted into the dielectric tube, a thin wire conductor disposed adjacent to and surrounding the dielectric tube, and the dielectric tube and the thin wire conductor An outer cylinder disposed so as to surround the gas pipe, a gas inlet into the gap between the dielectric tube and the outer cylinder, and a gas outlet to the outside; between the inner electrode and the thin wire conductor By applying voltage, dielectric barrier discharge is caused between the thin wire conductor and the inner electrode via the dielectric tube, and the air current accompanying the generated ions is discharged to the outside. Ionized airflow generator. The outer cylinder constitutes an outer cylinder electrode made of a conductive metal and is disposed so as to be in electrical contact with the fine wire conductor, thereby applying a voltage between the inner electrode and the outer cylinder electrode to 2. The apparatus according to claim 1, wherein the device is configured to feed power to the thin wire conductor via the cylindrical electrode and to cause a dielectric barrier discharge between the thin wire conductor and the inner electrode via the dielectric tube. The apparatus according to claim 2, wherein an alternating voltage is applied between the inner electrode and the outer cylinder electrode, and the outer cylinder electrode is grounded. The apparatus according to claim 3, wherein the AC voltage is a DC superimposed AC voltage. The apparatus in any one of Claims 1-4 in which the several gas exhaust port is provided along the longitudinal direction of the said outer cylinder. The apparatus in any one of Claims 1-4 in which the slit-shaped gas exhaust port extended along the longitudinal direction of the said outer cylinder is provided. The apparatus according to any one of claims 1 to 6, wherein the thin wire conductor is a thin metal wire and is wound around the outer periphery of the dielectric tube in a coil shape at an appropriate interval.

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