JPH1027672A - Corona discharge device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a corona discharge device which can emit a negative ion in a condition suppressing emission of a positive ion. SOLUTION: An insulating layer 1 is set up in a device so as to place its lengthwise direction in parallel to an inflow direction 11 of air to a corona discharge device main unit. Induction electrodes 3, 7 are arranged in a region to the windward of the insulating layer 1, the induction electrode 7 is arranged to be separated from the induction electrode 3 in a region to the lee of the insulating layer 1. A discharge electrode 5, in a position in the upward from the induction electrodes 3, 7 in the insulating layer 1, is arranged so as to be partially opposed to the induction electrodes 3, 7 in a central part of the insulating layer 1 along a center line in the lengthwise direction of the insulating layer 1. A frequency of a negative potential drive power source 9 is set to 80kHz or less, to respectively connect its high voltage output terminal to the induction electrode 7 and its earth terminal to the induction electrode 3. A side of the induction electrode 7 is set to high voltage of negative potential, the discharge electrode 5 is placed electrically in a float condition. In this way, in a generated positive ion, its emission to outside the device is suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a corona discharge device having a corona discharge element for generating ozone and ions from the air by surface corona discharge.

[0002]

2. Description of the Related Art Conventionally, in a corona discharge device, a negative AC high voltage is applied to a discharge electrode and an induction electrode which constitute a corona discharge element and face each other with an insulating layer interposed therebetween, and a creeping surface is formed near the discharge electrode. 2. Description of the Related Art There is known an apparatus which generates corona discharge and thereby releases ozone and negative ions generated from the atmosphere to the outside.

[0003]

By the way, in the corona discharge device having the above structure, only negative ions out of the generated ions should be discharged outside the device in principle. However, when the apparatus is actually driven, a considerable amount of positive ions may be emitted to the outside of the apparatus together with negative ions depending on the driving conditions. Therefore, the purpose of the corona discharge device, which emits only negative ions, cannot be achieved.

Accordingly, it is an object of the present invention to provide a corona discharge device capable of emitting negative ions while suppressing the emission of positive ions.

[0005]

A corona discharge device according to a first aspect of the present invention comprises a corona discharge element for generating negative ions from air by creeping corona discharge between a plurality of electrodes. Has an AC power supply for applying a negative voltage to one of the plurality of electrodes, and the frequency of the AC power supply is set to 80 kHz or less.

Here, the corona discharge device is usually used in combination with a fan for sending air into the device.
Therefore, the positive ions generated by the creeping corona discharge exert the action of the combined force of the force of the sent air flow and the Coulomb force whose magnitude is determined by the potential difference between the corona discharge element and the positive ions. Will receive it. If the frequency of the AC power supply is as low as 80 kHz or less, the time required for the potential of the corona discharge element to change correspondingly increases. That is, during the time when the output voltage of the AC power supply changes in the direction to increase the potential difference between the positive ion and the electrode to which the negative voltage is applied, the positive ions are collected by the corona discharge element by the action of the combined force. It is long enough. Therefore, the positive ions are carried to the corona discharge element by the combined force, and are collected by the corona discharge element. This fact is a novel finding obtained from the results of experiments performed by the present inventors.

In a preferred embodiment according to the first aspect of the present invention, an electrode to which a negative voltage is applied among a plurality of electrodes is arranged downstream of an air flow flowing into the device.

This is because the force of the air flow sent into the apparatus is taken into account. That is, by setting the electrode on the leeward side to a high voltage of a negative potential as in the above configuration, the Coulomb force acting on the positive ions can be increased, and the corona discharge elements can collect the positive ions efficiently. This is because a combined force having a proper size and direction can be obtained.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIGS. 1 and 2 show an embodiment of a corona discharge element provided in the corona discharge device of the present invention. FIG. 1 is a plan view showing an embodiment of a corona discharge element, and FIG.
FIG. 2 is a cross-sectional view showing one embodiment of a corona discharge element.

As shown in the figure, the corona discharge device includes a corona discharge element 2 including an insulating layer 1, induction electrodes 3 and 7, and a discharge electrode 5, and a negative potential is applied to the induction electrodes 3 and 7. A creeping corona discharge is generated near the discharge electrode 5 by connecting the driving power supply 9 to generate ozone and ions from the atmosphere.

Next, each component of the corona discharge element 2 will be described.

The corona discharge element 2 has a rectangular shape having a predetermined thickness, and its length direction is the direction in which air flows into a corona discharge device main body (not shown) (indicated by an arrow 11 in FIG. 2). Are installed in a corona discharge device (not shown) so as to be in parallel with.

Each of the induction electrodes 3 and 7 is formed in a rectangular shape. The induction electrode 3 is disposed in a region of the insulating layer 1 that is closer to the upstream of the inflow direction of the air (that is, upwind), and the induction electrode 7 is located in the region of the insulation layer 1 that is closer to the downstream of the inflow direction of the air (that is, downstream). It is arranged in a region away from the induction electrode 3.

The discharge electrode 5 constitutes the corona discharge element 2 together with the induction electrodes 3 and 7, and is formed in a belt shape. The discharge electrode 5 is located at a position above the induction electrodes 3 and 7 in the insulating layer 1 and at a central portion of the insulating layer 1 along the longitudinal center line of the insulating layer 1 and partially with the induction electrodes 3 and 7. They are arranged to face each other.

In the present embodiment, an AC high-voltage power supply whose frequency is set to 80 kHz or less is used as the negative potential driving power supply 9. The high-voltage output terminal of the AC high-voltage power supply is connected to the induction electrode 7 and the ground terminal thereof is connected to the induction electrode 3 to set the induction electrode 7 side to a negative high voltage and to set the discharge electrode 5 to a negative potential. , In an electrically floating state.

In the above configuration, ozone and positive and negative ions are generated by creeping discharge generated near the discharge electrode 5. Most of the generated positive and negative ions are discharged to the outside of the apparatus together with ozone by an air flow (indicated by an arrow 11) passing through a corona discharge device (not shown). The release of positive ions to the outside of the apparatus is suppressed (see FIG. 2). This is a fact confirmed as a result of the inventors' experiments.

Therefore, in a corona discharge device for obtaining negative ions together with ozone from the air, as in this embodiment,
The configuration in which the leeward electrode (induction electrode 7) is set to a higher voltage than the leeward electrode (induction electrode 3) using an AC high-voltage power supply whose frequency is set to 80 kHz or less is a result of an experiment conducted by the present inventors. It is based on the obtained new knowledge.

Hereinafter, the experiments performed by the present inventors and new findings obtained by the experiments will be described in detail with reference to FIGS.

The motivation that led the present inventors to carry out an experiment as described below is that positive ions are emitted outside the corona discharge device and the frequency of the AC high voltage power supply applied to the corona discharge element 2 is changed. It is speculated that there is some relationship between the two. In other words, the present inventors suppress emission of positive ions when the frequency of the AC high-voltage power supply applied to the corona discharge element 2 is low, but when the frequency of the AC high-voltage power supply exceeds a certain frequency. The following experiment was performed under the expectation that the release of positive ions would start.

FIG. 3 is a characteristic diagram showing the relationship between the power supply frequency (kHz) near the corona discharge element 2 and the ion concentration in the air. The data shown in FIG. 3 was sampled while the frequency of the above-described AC high-voltage power supply was connected to the corona discharge element 2 while the frequency of the fan was changed to a predetermined value while controlling the rotation speed of the fan that blows air into the corona discharge device. Things.

In FIG. 3, solid lines a and b are curves showing the relationship between the power supply frequency and the ion concentration when the induction electrode 7 is set to a high voltage in the leeward electrode, that is, in the above-described device. The solid line a shows the relationship between the power supply frequency and the negative ion concentration, and the solid line b shows the relationship between the power supply frequency and the positive ion concentration.

As is clear from the figure, the positive ion concentration is
Power supply frequency rises sharply from around 80kHz to 82k
Hz, it exceeds the negative ion concentration,
At Hz, there is a considerable difference from the negative ion concentration. In other words, it can be seen that the positive ions emitted from the corona discharge element 2 rapidly increase near the power supply frequency exceeding 80 kHz.

It is considered that such a phenomenon occurs due to the following reasons.

That is, the corona discharge device is usually used in combination with a fan (not shown) for sending air into the device as in the above experiment. Therefore, as shown in FIG.
Is the force of the air flow (the force of the wind) F1 and the corona discharge element 2
(In this case, the induction electrode 7) and the combined force F3 of the Coulomb force F2 whose magnitude is determined according to the potential difference between the positive ions p.

Here, if the frequency of the above-mentioned negative potential drive power supply (AC high voltage power supply) 9 is in a region lower than 80 kHz, the time required for the polarity of the induction electrode 7 to change correspondingly becomes longer. . That is, as shown in FIG.
Time T1 during which the output voltage of the AC high-voltage power supply changes in the direction of the arrow to increase the potential difference between positive ions p and induction electrode 7
Has a length sufficient to allow the positive ions p to be collected at a site near the discharge electrode 5 by the combined force F3. Therefore, as shown in FIG. 6, the positive ions p generated by the above-described creeping corona discharge are carried by the combined force F3 having the size and direction as shown in the drawing, and are collected in the vicinity of the discharge electrode 5. Will be done.

On the other hand, if the frequency of the AC high-voltage power supply is higher than 80 kHz, the time required for the polarity of the induction electrode 7 to change correspondingly becomes shorter. That is, as shown in FIG. 7, during the time T1 'in which the output voltage of the AC high-voltage power supply changes in the direction of the arrow that increases the potential difference between the positive ions p and the induction electrode 7, the positive ions p are discharged by the combined force F3. The length is too short to be collected at a site near the electrode 5.

Therefore, the direction of the Coulomb force F2 shown in FIG. 4 changes in a direction opposite to the direction shown in FIG. 4 before the positive ions p reach the vicinity of the discharge electrode 5. Accordingly, the direction of the resultant force F3 also changes from the direction in which the positive ions p approach the site near the discharge electrode 5 as shown in FIG. Then, when the output voltage of the AC high-voltage power supply changes again from the direction of the arrow that reduces the potential difference between the positive ion p and the induction electrode 7 to the direction of the arrow while the positive ions p are not completely separated from the vicinity of the discharge electrode 5. The direction of the Coulomb force F2 changes again to the direction shown in FIG. 4, and accordingly, the direction of the resultant force F3 also changes from the direction in which the positive ions p are moved away from the vicinity of the discharge electrode 5 as shown in FIG. Will change.

That is, as is apparent from the figure, the positive ions p are transported in the direction of approaching and away from the vicinity of the discharge electrode 5 by the resultant force F3 whose direction changes, and eventually the discharge electrode 5 Is released to the outside of the device without being collected in the vicinity of the device.

From the above experimental results, the present inventors have found that the frequency of the AC high-voltage power supply applied to the corona discharge element 2 is 80
It has been newly obtained that a frequency lower than kHz is an effective means for suppressing the emission of positive ions from the corona discharge device.

In the above experiment, in the corona discharge element 2 having the configuration shown in FIGS. 1 and 2, a device in which the leeward dielectric electrode 7 was set to a high negative voltage was used. This is because the wind force F1 shown in FIG. 4 was considered. That is, by setting the leeward electrode to a high negative voltage, the Coulomb force F2 acting on the positive ions p can be increased, and the corona discharge element 2 efficiently collects the positive ions p. This is because a resultant force F3 having a size and a direction that can be obtained is obtained.

The above description relates only to one embodiment of the present invention, and does not mean that the present invention is limited only to the above content.

For example, in the above-described embodiment, a corona discharge element having two induction electrodes has been described. However, a corona discharge element having one induction electrode on the windward side and a discharge electrode on the leeward side has been described. The present invention is also applicable to elements. In this case, if the discharge electrode side is set to a high negative voltage, an excellent positive ion trapping effect similar to that of the above-described embodiment can be obtained.

[0034]

As described above, according to the present invention,
A corona discharge device capable of emitting negative ions while suppressing emission of positive ions can be provided.

[Brief description of the drawings]

FIG. 1 is a plan view of a corona discharge element according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of the corona discharge element of FIG.

FIG. 3 is a characteristic diagram showing a relationship between a power supply frequency near a corona discharge element and an ion concentration.

FIG. 4 is an explanatory diagram showing a force acting on positive ions when a leeward electrode is at a high negative potential voltage.

FIG. 5 is a diagram showing an output voltage waveform of an AC high-voltage power supply when a frequency is set low.

FIG. 6 is an explanatory diagram showing a combined force acting on positive ions when a leeward electrode is at a high negative potential voltage.

FIG. 7 is a diagram showing an output voltage waveform of an AC high-voltage power supply when a frequency is set high.

FIG. 8 is an explanatory diagram showing a combined force acting on positive ions when the leeward electrode is at a high negative potential voltage.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulating layer 2 Corona discharge element 3, 7 Induction electrode 5 Discharge electrode 9 Negative potential drive power supply 11 Wind direction

Claims (2)

[Claims] 1. A corona discharge device including a corona discharge element that generates negative ions from air by creeping corona discharge between a plurality of electrodes, wherein a negative voltage is applied to one of the plurality of electrodes of the corona discharge element. A corona discharge device having an AC power supply for applying voltage, wherein a frequency of the AC power supply is set to 80 kHz or less. 2. The corona discharge device according to claim 1, wherein an electrode to which a negative voltage is applied among the plurality of electrodes is arranged downstream of an air flow flowing into the device. apparatus.