JPS6355105A - Ozonizer - Google Patents

Abstract

PURPOSE:To contrive to miniaturize an ozonizer, to improve electric power efficiency and to make discharge electric current smooth, by impressing a specific high-voltage pulse and inverse bias voltage between a cylindrical or parallel electrode and an electrode which is set at the center of the electrode and has protrusions. CONSTITUTION:A linear or bar plus electrode 3 connected to a high-voltage pulse electric source device 4 is placed at the central part of an earthed cylindrical minus electrode 1 and is protrusively equipped with a great number of sharp-pointed projections or needles 2 in the radius direction. A high-voltage pulse having <=10mus pulse duration number is impressed between both the electrodes 1 and 3 and fine electronic streamer is formed between the tips of the projections 2 and the electrode 1. An oxygen-containing gas or air to be sent from an intake 7 is passed through discharge space 9 to give a formed ozone-containing gas from an outlet 8. Further inverse bias voltage having <=corona discharge starting voltage is impressed to the electrode 1 by an inverse bias DC electric source device 5. Consequently, ion cloud is removed from the discharge space 9 when pulse voltage becomes non-voltage, the amount of ozone formed is increased and space utilization is improved.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an ozone generator used for wet ozone oxidation simultaneous desulfurization and denitrification plants, sterilization of tap water, decolorization of wastewater in frozen ground treatment equipment, etc. The present invention relates to an ozone generator that can be miniaturized, improve power efficiency, and smooth the flow of discharge current.

[Prior art] A conventional ozone generator called a silent discharge type
As shown in the figure, a dielectric material C such as glass is placed between electrodes a and b to which a high-voltage AC voltage of more than 10 KV is applied to prevent arc discharge.
, b is limited to 5 mm or less. In addition. In the figure, j is an AC power source, r is a source gas inlet, and 9 is an outlet of the generated ozone-containing gas.

[Problems to be solved by the invention] However, with the above structure, the discharge space is small, which limits the flow rate of raw air, and it is necessary to set a large electrode area to produce a certain amount of ozone. As a result, the external dimensions of the device become thicker. In addition, small discharges in silent discharges are effective for ozone generation, but at the end of discharge they change to arc discharges that do not contribute much to ozone generation, resulting in problems such as large current consumption and low power efficiency (or generation efficiency). was there.

[Means for Solving the Problems] In view of the above-mentioned problems, the present invention has been made in order to miniaturize the device, improve ozone generation efficiency, and smooth the flow of discharge current. is an ozone generator that forms a discharge space between opposing electrodes and generates ozone from the oxygen-containing source gas or air supplied into the discharge space by utilizing the discharge action. a wire or rod-shaped electrode having a large number of protrusions or needles with pointed tips disposed at the center of the cylinder or between adjacent flat plates and facing the cylinder or flat plate; and the electrode. A high voltage pulse power supply device that applies a high voltage pulse with a pulse width of several 10 μS or less in between, and a reverse bias DC power supply device that applies a reverse bias voltage that is less than the corona discharge starting voltage to at least one electrode. be.

[Function] Since a DC high-pressure pulse discharge is performed, the ozone generation efficiency is improved and the device becomes smaller. Since the wire or rod-shaped discharge electrode is provided with a protrusion with a sharp tip, it is possible to generate a minute streamer, and the ozone generation efficiency is further improved. Furthermore, since the ion cloud remaining in the discharge space is removed by the reverse bias voltage when the high-voltage pulse voltage becomes non-voltage, the discharge current flows smoothly during the next discharge, increasing the amount of ozone produced.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. 1st
5 to 5 show an embodiment of the present invention. The electrode of this embodiment includes a negative electrode 1 formed in a cylindrical shape, and a protrusion with a sharp tip disposed at the center of the negative electrode 1. Alternatively, it is composed of a wire or rod-shaped positive electrode 3 with a large number of needles 2 protruding in the radial direction, and the distance between the tip of the protrusion 2 and the negative electrode 1 is set so that k≧20+nm.

The positive electrode 3 has a negative side grounded and has a pulse width of 1.
The negative electrode 1 is connected to the positive side of a high voltage pulse power supply 4 of 0 JIS or lower, and the negative electrode 1 is connected to the positive side of a reverse bias DC power supply 5 of a corona discharge starting voltage or lower, the negative side of which is grounded. In addition, in the figure, 6 is an insulator, 7
8 is an intake port for the oxygen-containing raw material gas or air, 8 is an outlet for the produced ozone-containing gas, and 9 is a discharge space.

Next, the operation of this device will be explained. When a high voltage pulse voltage is applied between the positive electrode 3 and the negative electrode 1,
A pulse discharge occurs between both electrodes 1.3, and a fine electron streamer 10 is formed between the tip of the protrusion 2 and the negative electrode 1 in the discharge space 9 (see Fig. 3), and the air or gas passing through it is formed. converts oxygen into ozone. At this time, the thinner and sharper the tip of the protrusion 2, the more the electronic streamer 10
are formed minutely, creating conditions favorable for ozone generation.

However, as the ozone concentration increases as the air flow flows downstream in the discharge space 9, a large amount of various cations and anions accumulate in the discharge space 9, as will be described later, and if left undisturbed, the discharge will occur. The current is suppressed and the streamer 10 also becomes non-uniform and short (see FIG. 4). That is, around the protrusion 2 on the downstream side, ozone 0312, which has a strong bonding force with electrons and becomes negatively charged, oxygen ions 0213, which have released electrons due to discharge, and nitrogen ions N, are present.
214 etc. gather together to form the ion cloud 15.
(see figure), this ion cloud 15 prevents discharge and attempts to reduce the amount of ozone produced. In contrast, in the present invention, a reverse bias voltage lower than the corona discharge starting voltage is applied to the negative electrode 1.
is constantly applied, so when the pulse voltage becomes no voltage, the cations 13 and 14 move to the positive electrode 3 side, and the anions 12 move to the negative electrode 1 side, and are removed from the discharge space 9. be done.

Therefore, when the next pulse voltage is applied, the discharge current flows smoothly, and the streamer IO also extends uniformly, resulting in an increase in the amount of ozone produced and an improvement in the space utilization efficiency.

A second embodiment of the invention is shown in FIGS. 6 and 7. In this example, the negative electrode 1a is composed of a plurality of parallel flat plate rows, and the positive electrode 3a is arranged in the middle between adjacent flat plates, but other than that, there is no difference from the first embodiment. .

A third embodiment of the invention is shown in FIG. In this example, a reverse bias voltage is applied to the positive electrode 3, a capacitor 16 is installed between the high voltage pulse power supply 4 and the positive electrode 3, and a resistor 17 is installed between the reverse bias DC power supply 5 and the positive electrode 3. Other than that, there is no difference from the first embodiment.

Note that the present invention is not limited to the above-described embodiments, and it goes without saying that various changes can be made without departing from the gist of the present invention.

[Effects of the Invention] As described above, the present invention exhibits the following excellent effects.

(i) Since pulse discharge is performed, it is possible to apply high voltage, and the spacing between electrodes can be expanded. Therefore, the device can be made smaller.

(ii) Ozone production efficiency can be improved for the same reason as in item (1), and since heat generation is extremely small, there is no need for cooling.

0 Since the positive electrode is provided with a protrusion or needle with a sharp tip, it is possible to generate a stable and fine streamer during discharge, and it is possible to improve ozone generation efficiency and space utilization efficiency.

(f) Since a reverse bias voltage lower than the corona discharge starting voltage is always applied, it is possible to smoothly flow a high-voltage pulse current, thereby increasing the amount of ozone generated and improving power efficiency.

[Brief explanation of drawings]

1 to 5 show a first embodiment of the present invention, FIG. 1 is a cutaway side view, FIG. 2 is a view taken from the direction of ■-■ in FIG. 1, and FIG. 3 is a good condition. Figure 4 is an explanatory diagram of how bad streamers are generated, Figure 5 is an explanatory diagram of how ion clouds are generated, and Figure 6 is an illustration of how bad streamers are generated.
FIG. 7 is a cutaway side view showing a portion of the third embodiment, FIG. 7 is a view taken from the direction of arrows ■-■ in FIG. FIG. 2 is a cutaway side view of a conventional ozone generator. In the figure, ■, 1a is a negative electrode, 2 is a protrusion or needle, 3
, 3a is a positive electrode, 4 is a high-voltage pulse power supply, and 5 is a reverse bias DC power supply.

Claims (1)

[Claims] 1) In an ozone generator that forms a discharge space between opposing electrodes and generates ozone from an oxygen-containing raw material gas or air supplied into the discharge space using a discharge action, a cylindrical or flat plate array of electrodes is used. a wire or rod-shaped electrode having a large number of protrusions or needles with pointed tips disposed at the center of the cylinder or between adjacent flat plates and facing the cylinder or flat plate, and the electrode. A high voltage pulse power supply device that applies a high voltage pulse with a pulse width of several 10 μs or less in between, and a reverse bias DC power supply device that applies a reverse bias voltage of less than the corona discharge starting voltage to at least one electrode. Characteristic ozone generator.