WO2008004433A1

WO2008004433A1 - Ozone generating device

Info

Publication number: WO2008004433A1
Application number: PCT/JP2007/062240
Authority: WO
Inventors: Masaru Nakanishi; Masaki Nieda
Original assignee: Ohnit Co., Ltd.
Priority date: 2006-07-04
Filing date: 2007-06-18
Publication date: 2008-01-10
Also published as: JP2009221023A

Abstract

The amount of ozone generated is not reduced while reducing the radiation of high-frequency noise from connection lines by preventing a high-frequency current generated in discharge electrodes from flowing into the connection lines and while reducing the effect of an applied voltage by preventing the high-frequency current from flowing into the connection lines. In an ozone generating device (4) for applying a high voltage from a drive circuit to discharge electrodes (41) to generate ozone by the silent discharge of the discharge electrodes (41), inductances (43) are provided to connection terminals (44) of the discharge electrodes (41) to obtain the ozone generating device (4) in which the connection lines extending from the drive circuit are connected to the discharge electrodes (41) through the inductances (43).

Description

Specification

Ozone generator

Technical field

The present invention relates to an ozone generator that reduces high-frequency noise (several hundred MHz to several GHz) generated by silent discharge.

Background art

An ozone generator generates silent discharge by applying an alternating high voltage to a discharge electrode, and ionizes a raw material gas (oxygen or air containing oxygen) by the silent discharge to generate ozone. Here, the silent discharge is a large number of minute pulse discharges that repeatedly generate and disappear in a short time (2n _Sec or less). The minute pulse discharge generates a high-frequency current, and radiates high-frequency noise (several hundred MHz to several GHz) using a connection line for applying a high voltage to the ozone generator as an antenna. This high-frequency noise is in the frequency band used for mobile phones and wireless LANs, for example, reducing the quality of mobile phone calls. Therefore, when using ozone generators, measures against high frequency noise are required.

[0003] The simplest countermeasure against high frequency noise is a method in which an ozone generator is surrounded by an electromagnetic shield. For example, a large industrial ozone generator has a configuration in which a raw material gas is supplied to an ozone generator through a metal pipe and the generated ozone is separately released through the metal pipe. For this reason, it is easy to enclose only the compartment where the ozone generator is placed with an electromagnetic shield, and the increase in manufacturing cost due to the addition of the electromagnetic seal is not a problem. However, since small-sized ozone generators for consumer use are aimed at miniaturization and low cost, it is usual to have a configuration in which ambient air is directly brought into contact with an ozone generator as raw material gas to generate ozone. It is. From this, it is not desirable to surround the ozone generator with an electromagnetic shield, and the increase in manufacturing cost due to the addition of the electromagnetic shield cannot be ignored, so it is not practical.

[0004] Next, as an easy countermeasure against high-frequency noise, it is conceivable to use a coaxial cable or a twisted pair cable that hardly emits high-frequency noise as a connection line. However, one end of the connection line is not grounded, even if it is a coaxial cable or twisted pair cable. Difficult to reduce wave noise radiation. In addition, when it is possible to reduce the emission of high-frequency noise from the connection line, the high-frequency current flows back to the drive circuit, and there is a possibility that high-frequency noise is emitted from the drive circuit side. Furthermore, there is a risk that the applied voltage, which is a high voltage, deteriorates the coating of the coaxial cable over time, causing current leakage due to dielectric breakdown.

[0005] Here, it is conceivable that a noise filter that prevents radiation of high-frequency noise is attached to the connection line. Even though a normal noise filter is effective for high-frequency noise mixed in a low-voltage signal voltage, the discharge electrode The emission of high-frequency noise radiated from the connecting line of the ozone generator that applies high voltage to cannot be reduced sufficiently. Therefore, Patent Document 1 forms a capacitor from the relationship between the discharge electrode and the dielectric electrode by forming a discharge electrode on a dielectric substrate and providing the dielectric electrode with respect to the discharge electrode. We propose a technology that reduces the occurrence of high-frequency noise due to silent discharge by connecting a resistor in series and consuming the high-frequency current of the applied voltage through the resistor. The capacitor composed of the discharge electrode and the dielectric electrode has an impedance for a high-frequency current of a small applied voltage of several pF, which is relatively small compared to the resistance, so that the high-frequency current is consumed by the resistor.

[0006] Patent Document 1: Japanese Patent No. 3339590 ([Claim 1], [0010], [0019])

Disclosure of the invention

Problems to be solved by the invention

[0007] Certainly, according to the configuration of Patent Document 1, since the impedance of the resistor is relatively larger than the capacitor with respect to the applied voltage, the high-frequency current is consumed by the resistor, and high-frequency noise is generated. Can be reduced. However, since the resistor acts as an impedance for the entire high voltage that generates silent discharge as well as the high-frequency current alone, there is a risk that the applied high voltage itself will be consumed. That is, there is a problem in that the amount of ozone generation is reduced as a result of reducing the amount of contribution to generation of silent discharge at a high voltage applied to the discharge electrode and reducing the efficiency of ozone generation.

[0008] In addition, the resistance that can withstand an applied voltage that normally reaches several kV is special, and as described above, it is not practical to use in an ozone generator aiming at miniaturization and cost reduction. . Therefore, prevent high-frequency current generated at the discharge electrode from flowing into the connection line. Thus, an ozone generator that does not decrease the ozone generation amount by reducing the influence of the applied voltage by preventing the high-frequency current from flowing into the connection line while reducing the emission of high-frequency noise from the connection line. Considered to develop.

Means for solving the problem

[0009] A device developed as a result of the study was developed by applying a high voltage from the drive circuit to the discharge electrode and generating ozone by silent discharge of the discharge electrode, and then inducting an inductance at the connection terminal of the discharge electrode. And an ozone generator in which a connection line extending from the drive circuit cable is connected to the discharge electrode via the inductance. As a specific element that becomes an inductance, a coil can be cited. Here, the “drive circuit” of the present invention is an electric circuit that supplies a high voltage to the ozone generator. For example, a control circuit that switches the frequency of the commercial AC voltage and a booster circuit that boosts the commercial AC voltage ( Transformer). The ozone generator is applied with an alternating high voltage from the secondary side of the booster circuit.

[0010] The present invention consumes only a high-frequency current due to an inductance that hardly affects an applied voltage having a relatively low frequency while having a high impedance to the high-frequency current generated at the discharge electrode. As a result, the emission of high-frequency noise from the connection line is reduced. Since the high-frequency current generated at the discharge electrode does not flow toward the drive circuit (secondary side of the booster circuit in the above example configuration), the inductance is provided as close to the discharge electrode as possible. It is desirable. That is, the inductance is preferably connected in series with the connection terminal of the discharge electrode or configured as the connection terminal of the discharge electrode.

[0011] Since the ozone generator has a configuration in which the discharge electrode or the connection terminal or connection line of the discharge electrode is connected to the inductance, the ozone generator rejects the high-frequency current force s leaking from the connection portion between the above-mentioned portions and the inductance. I can't. Therefore, the inductance is configured such that the discharge electrode or the connection portion of the discharge electrode with the connection terminal or the connection line is covered with an insulator, and preferably the connection portion and the inductance are integrally covered with the insulator. Here, when the inductance is composed of a coil, the entire coil including the discharge electrode or the connection terminal of the discharge electrode and the connection line is covered with an insulator.

The invention's effect [0012] According to the present invention, an ozone which consumes only a high-frequency current and reduces the influence of the high-frequency noise on the ozone generation amount as much as possible while reducing the emission of high-frequency noise mainly from the connection line. The generator can be provided. In addition, unlike the resistor of Patent Document 1, the coil that forms the inductance does not have to consider the withstand voltage against high voltage, so it can be used with a small coil for surface mounting that is easily available. Realization of cost reduction and cost reduction, as well as downsizing and low cost of the ozone generator.

[0013] For example, when a coil of 100 H to several mH is used as the inductance, although the frequency of the most reduced high frequency noise is different, a reduction effect of several dB to several tens dB over several hundred MHz to several GHz is confirmed. In view of ease of use and low manufacturing costs, cost effectiveness is great. Thus, the present invention has the effect of providing an easy and inexpensive high-frequency noise countermeasure in an ozone generator that applies a high voltage to the discharge electrode.

Brief Description of Drawings

FIG. 1 is a block diagram simply showing the configuration of an ozone generator using an ozone generator to which the present invention is applied.

FIG. 2 is a perspective view showing an example of an ozone generator to which the present invention is applied.

[Fig. 3] This is a spectrum analyzer screen that measured the high-frequency noise of Comparative Example 1 in which the inductance was not connected in series with the ozone generator.

[Fig. 4] This is a screen of a spectrum analyzer that measured the high-frequency noise of Example 1 in which an inductance of 1000 μH (lmH) was connected in series with an ozone generator.

FIG. 5 is a spectrum analyzer screen for measuring high-frequency noise in Example 2 in which an inductance of 2000 mH (2 mH) is connected in series to an ozone generator.

Explanation of symbols

[0015] 1 Ozone generator

2 Drive circuit

21 Control circuit

22 Booster circuit

221 Primary side 222 Secondary side

23 Metal cover

3 Commercial power

4 Ozone generator

41 Discharge electrode

42 glass tubes

43 Inductance (Coil element with lead wire)

44 Connection terminal

5 Connection line

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram simply showing the configuration of an ozone generator 1 using an ozone generator 4 to which the present invention is applied, and FIG. 2 is a perspective view showing an example of the ozone generator 4 to which the present invention is applied. FIG. The ozone generator 1 shown in this example is a standard configuration that is commonly found in the past.

As shown in FIG. 1, the ozone generator 1 of the present example comprises a drive circuit 2 from a control circuit 21 and a booster circuit 22, and the control circuit 21 is connected to a commercial power source 3 so that the booster The secondary side 222 of the circuit 22 is connected to the ozone generator 4 by a connection line 5. As a countermeasure against high-frequency noise, the product surrounds the ozone generator 4 with a metal cover 23, grounds the control circuit 21, and shorts the primary side 221 and the secondary side 222 of the booster circuit 2 2 (in Fig. 1). (See dashed line). The ozone generator 4 of this example is not a creeping discharge method in which silent discharge is performed at the edge of the plate-like discharge electrode. However, the present invention can be applied to a silent discharge type ozone generator in which there is no difference in the effect of reducing high frequency noise due to the difference in specific discharge method. From this, even the creeping discharge type ozone generator can reduce high-frequency noise by the configuration shown in FIG.

[0018] As shown in FIG. 2, the ozone generator 4 of this example is melted in a state where a pair of glass tubes 42, 42, through which rod-shaped discharge electrodes 41, 41 are inserted, are arranged in parallel. The discharge electrode 41 is hermetically sealed to each glass tube 42 and the glass tubes 42 and 42 are integrated in close contact with each other, and an inductance (coil element with a lead wire) 43 is connected to the discharge electrode 41 protruding from each glass tube 42. In this configuration, the lead wire of the inductance 43 is used as the connection terminal 44. Inn The ductance 43 may be a surface mount coil element. In addition, in order to prevent leakage current due to the force of the connection portion between the discharge electrode 41 and the connection wire 5 and the inductance 43, it is desirable to cover the connection portion and the inductance 43 integrally with insulating grease or the like.

[0019] The glass tube 42 is a relatively easily available and inexpensive insulator, and as described above, the discharge electrode 41 is melted and the glass tubes 42 and 42 are easily connected to each other. Is excellent. Here, when the glass tube 42 is heated and melted after the discharge electrode 41 is inserted, the discharge electrode 41 also thermally expands. Therefore, it is desirable that the thermal expansion coefficients of the glass tube 42 and the discharge electrode 41 are approximate. For example, if the discharge electrode 41 was constituted by a tungsten wire, because of its thermal expansion force 10- ⁶ / K tungsten, the glass tube 42 is the use of borosilicate glass thermal expansion coefficient is 3.8 X 10- kappa Good. In this case, when the glass tube 42 inserted through the discharge electrode 41 is heated to 950 ° C. to 1000 ° C., the discharge electrode 41 can be sealed and the glass tubes 42 and 42 can be connected to each other by melting.

[0020] In the ozone generator 4 of this example, both discharge electrodes 41 and 41 are electrically cut off by the glass tube 42 enclosing each discharge electrode 41, and silent discharge is generated between the surfaces of the opposing glass tube 42. Then, ozone is generated from the supplied raw material gas (oxygen or air containing oxygen). The high frequency noise is radiated from the connection line 5 when the high frequency current resulting from the silent discharge attempts to return to the secondary side 222 of the booster circuit 22 in the drive circuit 2 through the connection line 5. The inductance 43 connected in series to the ozone generator 4 consumes a high-frequency current that tends to flow from the discharge electrode 41 to the connection line 5, thereby reducing the flow of the high-frequency current to the connection line 5. The high frequency noise radiated by the high frequency current flowing through 5 is reduced. Example

[0021] In order to confirm the effect of reducing high-frequency noise due to the inductance connected in series with the ozone generator, the drive circuit (control circuit and booster circuit), connection line, and ozone generator are equivalent to the above block diagram (see Fig. 1). The measurement circuit was assembled and the received intensity of high frequency noise radiated from the measurement circuit was measured.

[0022] The ozone generator used was configured as shown in the above example (Fig. 2), the glass tube was 40 mm long, 1.0 mm diameter borosilicate glass, and the discharge electrode was 0.5 mm diameter tungsten wire. . The ozone generator of the above specifications uses the ambient air as the raw material gas and is a booster circuit of the drive circuit. When AC high voltage of 30kHz, 5.6kV ~ 5.8kV is applied, 10mg / l! Generates ~ 12mg / h ozone.

[0023] The measurement circuit is configured such that the ozone generator is not surrounded by a metal cover, and the primary side and the secondary side of the drive circuit and the booster circuit are not grounded. The length of the connecting line is 180mm. The measuring device used a 150 mm diameter loop antenna installed at a distance of ozone generating strength of 40 mm as a probe, and displayed the high frequency noise received by the probe on the spectrum analyzer screen. The high frequency noise was measured by reading the display value at a specific frequency from the waveform displayed on the spectrum analyzer screen as the received intensity including the high frequency noise.

[0024] First, the effect of reducing high-frequency noise based on the difference in inductance capacity was measured. Reference Comparative Example 1 has no inductance (that is, as usual), Example 1 has 1000 H (lmH) inductance (one coil element with 1000 μ1000 lead wire), and Example 2 has 2000 mH (2 mH) ) Inductance (two 1000 μΗ lead coil elements). In this measurement, the coil elements with lead wires, which are separate from the ozone generator, are connected in series by clips, etc. for the convenience of changing the inductance capacity.

[0025] [Table 1]

The measurement results are shown in Table 1, the spectrum analyzer screen of Comparative Example 1 is shown in Fig. 3, the spectrum analyzer screen of Example 1 is shown in Fig. 4, and the spectrum analyzer screen of Example 2 is shown in Fig. 5. Each spectrum analyzer screen has a frequency of 0Hz to 2GHz on the horizontal axis. The vertical axis is -100 dB to OdB in signal strength. In each screen, the lower band is the reception intensity of the ambient noise displayed in real time, and the upper line is the reception intensity of the high-frequency noise. In Table 1, “Frequency (MHz)” is the frequency of the received intensity measured as high-frequency noise, “Noise (dB)” is the maximum value of the received intensity measured as high-frequency noise, and “Reduction (dB)” is a comparison. Represents the absolute value of the received power reduced from the average or maximum value in Example 1.

[0027] In Comparative Example 1 as a reference, high-frequency noise with an average value = -36.4 dB and a maximum value = _25.7 dB was measured, but in Example 1, the average value = -40.7 dB and the maximum value = -29.8 dB. The high frequency noise was measured and a reduction effect of 4.3 dB on average and 4. ldB on the maximum was confirmed for Comparative Example 1. Similarly, in Example 2, high-frequency noise with an average value of −45.0 dB and a maximum value of 33.5 dB was measured, and a reduction effect of 8.6 dB with an average value and 7.8 dB with a maximum value was confirmed compared to Comparative Example 1. Was done. In addition, as a result of repeating the same type of measurement, a reduction effect of 10 dB or more on average was confirmed.

[0028] From the above measurement results, it is clear that high-frequency noise is reduced by adding inductance. Here, in FIGS. 3 to 5, a peak is observed at a frequency of 80 Hz in the real-time reception intensity band, which is a transmission / reception signal of a mobile phone used in the vicinity of the measurement location. Compared with the transmission / reception signal of this cellular phone, the magnitude of the high-frequency noise radiated from the ozone generator can be grasped, and the degree of the high-frequency noise reduction effect of the present invention can be understood. It was also confirmed that the effect of reducing high-frequency noise increases with increasing inductance, although it is not completely proportional. In reality, when the inductance is increased, the coil element also becomes larger. Therefore, it is preferable to use a coil element having as large an inductance as possible within a range that can be incorporated into an ozone generator or an ozone generator.

[0029] Next, other high-frequency noise countermeasures that can be used in combination with the present invention are applied to the measurement circuit, and the synergistic effect of the present invention and other high-frequency noise countermeasures is recognized. Was measured. Other high-frequency noise countermeasures used for this measurement are: Countermeasure 1 Metal cover surrounding ozone generator

Countermeasure 2 Grounding the drive circuit

Measure 3 Short circuit on primary side and secondary side of booster circuit It is. The metal cover in Measure 1 is a SUS cover formed in the same way as an actual product. Since the raw material gas flows into the ozone generator and the generated ozone is discharged together with the remaining air, it has an opening that communicates with the outside and has almost no electromagnetic shielding effect. In addition, the short circuit on the primary side and secondary side of the booster circuit in Measure 3 is also grounded on the secondary side via the primary side that is grounded together with the grounded drive circuit.

[0030] As a reference, Example 1 was measured again. Example 3 in which Measure 1 was applied to Example 1, Example 4 in which Measure 2 was added to Example 3 and Example 3 in which Measure 3 was added to Example 4 Example 5 was measured respectively. In addition, in order to determine the effectiveness of the combination of the presence / absence of inductance and other countermeasures against high-frequency noise, the above Comparative Example 1 was measured again as a reference for comparison, and the Comparative Example 1 was compared with Countermeasure 1. Example 2, Comparative Example 3 in which Countermeasure 2 was added to Comparative Example 2 and Comparative Example 4 in which Countermeasure 3 was added to Comparative Example 3 were also measured.

[0031] [Table 2]

[0032] [Table 3]

Example The measurement results of Examples 3 to 5 are shown in Table 2, and the measurement results of Comparative Examples 1 to 4 are shown in Table 3, respectively. In Tables 2 and 3, “frequency (MHz)” and “noise (dB)” are the same as in Table 1 above.

[0034] As long as Example 1 and Examples 3 to 5 are compared and contrasted, measures are taken in addition to inductance. Even if measures 1 to 3 are applied, the high frequency noise reduction effect does not appear to have been improved. Here, if Comparative Example 1 and Comparative Examples 2 to 4 are compared and contrasted, it is confirmed that Measure 1 to Measure 3 certainly have an effect of reducing high-frequency noise. In addition, Example 3 and Comparative Example 2 where Countermeasure 1 was applied, Example 4 and Comparative Example 3 where Countermeasure 1 and Countermeasure 2 were applied, and Example 5 and Comparative Example 4 where Countermeasures 1 to 3 were applied, respectively. In comparison, as can be seen, the effect of reducing high-frequency noise is clearly improved by adding inductance. From now on, if the conventionally known measures 1 to 3 are taken, the high frequency noise can be surely reduced, but it does not reach the reduction effect by providing the inductance as in the present invention, and if the inductance is provided. Therefore, it is understood that there is a high reduction effect without taking measures 1 to 3.

Claims

The scope of the claims

[1] In an ozone generator that applies high voltage from the drive circuit to the discharge electrode and generates ozone by silent discharge of the discharge electrode, an inductance is provided at the connection terminal of the discharge electrode, and the connection line extends from the drive circuit Is connected to the discharge electrode through the inductance.

[2] The ozone generator according to claim 1, wherein the inductance is connected in series with the connection terminal of the discharge electrode.

[3] The ozone generator according to claim 1, wherein the inductance is configured as a connection terminal of the discharge electrode.

[4] The ozone generator according to any one of claims 1 to 3, wherein the inductance is at least a discharge electrode or a connection portion of the discharge electrode connected to a connection terminal or a connection line.