JPH09241007A - Ozone generating method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently obtain ozone by impressing a high pulse voltage between a high-voltage electrode and a grounded electrode to form a steep discharge current after an electric discharge is started and generating concd. ozone. SOLUTION: An ozonizer formed with a discharge electrode part consisting of a DC power source, an inverter, a current limit reactor, a boost-up transformer and the high-voltage electrode and grounded electrode with a dielectric in between is used. An AC pulse voltage generated in the inverter with an input to the power source is impressed on the discharge electrode part through the current limit reactor and boost transformer. After an electric discharge is started by the rising of a high-voltage pulse, a discharge current rises at a sufficiently higher rate than an ionizing rate due to a steep pulse current, hence an ozonizing reaction proceeds before ion is generated, and concd. ozone is efficiently obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for generating ozone by silent discharge or creeping discharge, and particularly by interposing a dielectric between a high voltage electrode and a ground electrode so that a void is formed between the electrodes. The present invention relates to an ozone generating method and apparatus for generating high-concentration ozone by causing discharge by applying a high-voltage pulse voltage while flowing oxygen gas between both electrodes.

[0002]

2. Description of the Related Art FIG. 4 shows a circuit configuration of a conventional ozone generator. A commercial AC power supply is rectified by a converter unit (not shown) to form a DC power supply unit 11. The DC power supply unit 11 supplies DC power to the inverter unit 12, and an AC pulse voltage is formed between the middle points c and d of the bridge circuit. The AC pulse voltage formed in the inverter section is converted into a high-voltage pulse voltage by the step-up transformer 13, and the discharge electrode section 1 in which a dielectric material is interposed between the high-voltage electrode and the ground electrode.
5 is applied. Step-up transformer 13 and inverter section 12
A current limiting reactor La is connected between and. The current limiting reactor La is provided for the purpose of, for example, limiting and protecting a transient current from flowing through the switching element of the inverter unit 12.

FIG. 5 shows waveforms of a voltage V applied to the discharge electrode and a current I flowing through the discharge electrode according to the above circuit. The voltage V applied to both ends of the discharge electrode 15 has a substantially trapezoidal waveform as shown because the AC pulse formed by the inverter unit 12 is applied via the current limiting reactor 14 and the step-up transformer 13. . Discharge electrode 1
No. 5 has a dielectric material interposed between the high voltage electrode and the ground electrode, and therefore has a capacitive load shown in the equivalent circuit shown in the figure. In the circuit of the discharge electrode 15 indicated by the dotted line in the figure, the switch S is in the discharge state when closed,
It shows that a discharge current flows through the equivalent discharge resistance R, and when it is open, it shows a state where it is not discharged. Since the load is capacitive, the current I flowing through the discharge electrode 15 is
First, the charging current flows, and the voltage V rises to the voltage E.
At b, discharge current flows. The discharge current flows during the discharge period T, after which the discharge stops and the current stops flowing. Therefore, the current I has a pulse-like waveform with a relatively low peak value as shown in the figure. When the rise of the voltage waveform V becomes larger than the discharge start voltage Eb, the rise curve slightly goes down because of the voltage drop of the resistance component due to the discharge current.

[0004]

In the circuit configuration of such a conventional ozone generator, when ozone is generated from high-purity oxygen gas as a raw material, ions are generated when the high-voltage pulse voltage rises, which hinders ozone generation. However, there is a problem that the energy efficiency is poor and the ozone concentration decreases with the discharge time, resulting in lack of stability. This is because in the circuit configuration of the ozone generator described above, the current is limited by using the current limiting reactor La, so that the rise of the discharge current becomes slow and the rise of the high-voltage pulse voltage becomes slow as shown in FIG. During discharge, the ion concentration increases between the discharge electrodes, the electron concentration decreases, and the excited molecular weight decreases. Therefore, there is a problem that ozone is less likely to be generated.

In addition, for example, nitrogen gas (N
_A third substance such as ₂ ) was needed. This is because the third substance acts as a catalyst that prevents the ozone generation reaction from being suppressed by the accumulation of an ion layer on the surface of the electrode when the ion concentration increases. For that reason, there is a problem that a gas to be added and a facility for flowing the gas are required, the running cost is high, and the apparatus is large.

The present invention has been made in view of the above-mentioned circumstances, and the discharge current is suddenly raised at a rate faster than the ion generation rate during discharge, whereby a stable and high concentration is achieved before the ions are generated. It is an object of the present invention to provide an ozone generating method and apparatus capable of generating ozone.

[0007]

In the ozone generating method of the present invention, a dielectric is interposed between a high voltage electrode and a ground electrode, and a high voltage pulse voltage is applied between the high voltage electrode and the ground electrode to produce a silent voice. In a method of generating discharge or creeping discharge and passing oxygen gas into the discharge space to generate ozone, a high-concentration ozone is generated by forming a sharp discharge current at the rising of the high-voltage pulse. Is characterized by.

Further, the ozone generator of the present invention includes a DC power supply section, an inverter section for generating an AC pulse voltage, a step-up transformer for stepping up the AC pulse voltage generated by the inverter section, and an output of the step-up transformer. An ozone generator comprising a discharge electrode portion connected to an end of the ozone generator is provided with means for rapidly raising a discharge current between the discharge electrodes after the start of discharge due to the rise of the AC pulse voltage.

According to the above-described present invention, the discharge current is rapidly raised at a rate faster than the ion generation rate, so that before the ions that suppress the generation of ozone are generated,
A large amount of ozone can be stably generated.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the attached FIGS.

FIG. 1 shows a circuit configuration of an ozone generator according to a first embodiment of the present invention, and FIG. 2 shows a voltage V and a current I applied to a discharge electrode according to the circuit configuration. Also in this embodiment, the basic configuration of the circuit including the DC power supply unit 11, the inverter unit 12, the step-up transformer 13, the discharge electrode 15 and the like is the same as the conventional technique, and the same elements are designated by the same reference numerals. Duplicate description is omitted. In the present embodiment, the current limiting reactor portion 14 has a series connection of the reactors Ls and Lb and a series-parallel connection with the reactor La. Among these, the current limiting reactor Ls is configured such that its inductance is saturated at the current value when the discharge starting voltage Eb is reached.

Therefore, the reactor Lac between points a and c is
Since the series circuit of the reactors Ls and Lb and the reactor La are connected in parallel, the combined reactor value expression is (1).

[Equation 1] When the discharge start voltage Eb is exceeded, the reactor L _S is saturated, and therefore the equation (2) is obtained.

[Equation 2]

Further, when the semiconductor switching element of the inverter section is turned off, the current limiting reactor Lac between points a and c releases energy. Energy is returned to the power supply, but at that time the reactor Ls is saturated first,
The reactor between points a and c is a parallel circuit of reactor La and reactor Lb. Then, when the current flowing through the reactor Ls decreases and the impedance is restored, the reactor between the points a and c becomes as shown by the equation (1).

When the current limiting reactor changes as described above, the current flowing through the discharge electrode 15 rises sharply after passing the discharge start voltage Eb as shown in FIG. Due to this steep impulse-like current, the discharge electrode 1
Since the discharge current rises between the high voltage electrode of 5 and the ground electrode at a rate sufficiently faster than the ion generation rate, the ozone generation reaction can be sufficiently performed before the ions are generated,
A large amount of ozone can be efficiently generated.

FIG. 3 shows the circuit configuration of an ozone generator according to the second embodiment of the present invention. In this embodiment, a switching element 18 is connected in parallel with the current limiting reactor La between the DC power supply unit 11. By turning on the switching element 18 immediately after the discharge electrode 15 starts discharging, a steep pulse current can be supplied to the discharge electrode 15 via the step-up transformer 13. The steep pulse current causes the discharge current to rise at a rate sufficiently higher than the ion generation rate as in the first embodiment, so that stable and high-concentration ozone generation can be performed before ions are generated.

The above-mentioned embodiments show two examples of a method of flowing a steep discharge current between the discharge electrodes of the ozone generator after the start of discharge. It is needless to say that the present invention is not limited to these embodiments, and various modified embodiments are possible for realizing the gist of the present invention.

[0017]

According to the present invention as described above,
By rapidly raising the discharge current between the discharge electrodes of the ozone generator after the start of discharge, without impairing the power supply efficiency,
It is possible to generate stable high concentration ozone. Further, in the case of producing high-concentration ozone, conventionally, for example, a third gas such as N ₂ gas is used.
Although a substance was required, the present invention enables high concentration ozone production without the use of such a third substance. Therefore, for example, a facility for flowing N ₂ gas is not required, and the ozone generator can be downsized and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an ozone generator according to a first embodiment of the present invention.

2 is a voltage V and a current I of a discharge electrode section according to the circuit of FIG.
FIG.

FIG. 3 is a circuit diagram of an ozone generator according to a second embodiment of the present invention.

FIG. 4 is a circuit diagram of a conventional ozone generator.

5 is a voltage V and a current I of a discharge electrode section according to the circuit of FIG.
FIG.

[Explanation of symbols]

 11 DC power supply section 12 Inverter section 13 Step-up transformer 14 Current limiting reactor 15 Discharge electrodes La, Lb, Ls Current limiting reactor

Claims (2)

[Claims] 1. A dielectric is interposed between a high-voltage electrode and a ground electrode, and a high-voltage pulse voltage is applied between the high-voltage electrode and the ground electrode to generate silent discharge or creeping discharge, and the discharge space In the method for generating ozone by passing oxygen gas through the substrate, a high-concentration ozone is generated by forming a steep discharge current at the rising of the high-voltage pulse. 2. A DC power supply unit, an inverter unit for generating an AC pulse voltage, a booster transformer for boosting the AC pulse voltage generated by the inverter unit, and a discharge electrode unit connected to the output terminal of the booster transformer. The ozone generating device according to claim 1, further comprising means for rapidly raising a discharge current between the discharge electrodes after the start of discharge due to the rise of the AC pulse voltage.