JPH0121081B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to an ozone generator using silent discharge, and particularly to a power source thereof. Ozone generators using silent discharge are the only means of producing ozone on an industrial scale, and have been used to sterilize and deodorize tap water, as well as decolorize, deodorize, and make wastewater pollution-free. is required. On the other hand, the demand for ultra-small and low-cost products for experimental use and for sterilizing cold drinking water is becoming even higher. Silent discharge is a streamer-shaped discharge obtained by placing an insulator between opposing electrodes with a gap between them and applying a high AC voltage between the two electrodes. Oxygen or oxygen-containing gas is passed through this discharge gap. Ozone is obtained by doing this.

[Prior art and its problems]

The power sources that have been put to practical use in the past for this ozone generator are: (a) Induction voltage regulator - step-up transformer (b) AC power regulator - step-up transformer (c) Voltage rectangular inverter - step-up transformer (d) Current There are combinations such as a rectangular inverter and a step-up transformer, and attached circuit elements are provided to suit each type. The advantages and disadvantages of the operation of these power supply units will be briefly explained using the single line diagram of the electrical system shown in FIG. 1 and the explanatory diagram of voltage and current waveforms shown in FIG.

In the combination of the inductive voltage regulator 1 and the step-up transformer 2 shown in FIGS. For this reason, the ozone generator current waveform 10 is greatly distorted as shown in the figure with respect to the ozone generator applied voltage waveform 9, and due to harmonic current components, 100% compensation is not possible even with the power factor compensation reactor 4. Can not. Although such a power supply is simple in construction and robust, it has the following drawbacks.

(1) Current harmonics are not a particular problem in small devices, but they cause damage such as clicks in large devices.

(2) Since the increase in input power is based on a rise in voltage, it is impossible to input large amounts of power due to the withstand voltage of the insulator, which leads to the increase in the size of the equipment and at the same time limits the control range of the amount of ozone generated. becomes smaller.

(3) Since it is a commercial frequency (50, 60Hz) circuit, both the induction voltage regulator 1 and step-up transformer 2 are large.

The combination of the AC power regulator 6 and the step-up transformer shown in Fig. 1b and Fig. 2b is based on the AC power regulator 6 which conducts the thyristors connected in an anti-parallel manner every AC half wave with a variable firing phase. Power is supplied to the capacitive load ozone generator 3 via the step-up transformer 2, and a current limiting reactor 5 is inserted as an intermediate circuit to prevent current rush. With this power supply,
As is clear from FIG. 2b, both the voltage 9 and the current 10 applied to the ozone generator have large distorted waveforms. Therefore, in addition to the disadvantages of the combination of the induction voltage regulator 1 and the step-up transformer 2, there are other drawbacks such as a large cross-sectional area of the core of the step-up transformer, an inability to perform power factor compensation, and an increase in the equipment capacity. have specific drawbacks. In addition, illustration 11
indicates the power supply voltage.

1c and 2c show a power source that combines a voltage rectangular inverter 7 and a step-up transformer 2, which is the most stable variable frequency power source and is used as a power source for various devices. In this case, a current limiting reactor 5 for preventing rush current and a power factor compensating reactor 4 are inserted as an intermediate circuit. This power supply has many advantages such as variable voltage and frequency, wide control range, and ability to input large amounts of power, but it is very expensive as a power supply and has a major disadvantage of increasing the total cost of the ozone generator. have.

The combination of the current rectangular inverter 8 and the step-up transformer 2 shown in FIGS. unnecessary,
Accordingly, the circuit configuration is also simple. Like the voltage rectangular inverter 7, this current rectangular inverter 8 is also most commonly used for driving electric motors, and has the same effect as the voltage rectangular inverter 7 as a power supply section of an ozone generator. However, since it is inherently unstable as a power source, special consideration must be given to the configuration of the protection circuit and control circuit for actual operation. That is, special circuits are required for the occurrence of abnormal voltages, abnormal frequencies, disconnection of damaged tubes, restart conditions, etc.

Other inverters that use power transistors have been put into practical use, but since they were developed for industrial use, including the power supplies mentioned above, they are large and expensive, and they only require a few grams per gram. It cannot be applied to small appliances with an ozone generation amount of H _r .

[Purpose of the invention]

The purpose of this invention is to eliminate the drawbacks of the power supply section of the prior art ozone generator, and to provide a small and inexpensive power supply for the ozone generator for use in laboratories, cold drinking water sterilization, etc. shall be.

[Key points of the invention]

According to the present invention, this object can be achieved by combining a DC chopper circuit using transistors and a high voltage generation circuit using a DC high voltage coil. In other words, while it was previously believed that silent discharge was generated only by the application of AC high voltage,
Focusing on the phenomenon that occurs in response to voltage displacement, we aim to make effective use of the resonant oscillating voltage between the capacitance of the ozone generator and the DC high-voltage coil due to periodic and frequency-variable switching of DC current. This has been achieved.

[Embodiments of the invention]

FIG. 3 shows the basic configuration circuit of the present invention, and FIG. 4 is a schematic diagram of waveforms of each part for explaining the operation. In the present invention, first, a commercial power source is converted into a stable DC voltage source by a rectifier 12 and a smoothing capacitor 13. The primary windings 18a and 18b of the high voltage coil 18 and the collector and emitter of the switching transistor 17 are connected in series to this DC voltage source, and the secondary winding 18c of the high voltage coil 18 is connected in series with the DC voltage source. - An ozone generator is connected to 18d. For this main circuit, setting terminal 14
The oscillation circuit 15 generates the reference pulse 1 in response to the signal from the
9 is generated. (See Figure 4) Reference pulse 19
A control pulse 20 is generated by the pulse circuit 16 from the above, and is supplied as the base current of the transistor 17. Therefore, the transistor 17 becomes conductive only when the base current is supplied, and the high voltage coil 1
A current flows through the primary windings 18a and 18b of 8 from the DC voltage source. Then, when the base current is briefly cut off,
Energy 1/2 Li ² possessed by the primary coil L is supplied and supplied between the secondary coils 18c to 18d and the capacitance of the ozone generator connected thereto.

21 and 22 in Fig. 4 are the terminal voltages of the primary and secondary windings of the high-voltage coil observed at this time, and the peak-to-peak voltage of the secondary voltage is the voltage of the discharge voltage in the air gap of the ozone generator. If the amount is doubled or more, ozone will be generated. This voltage is adjusted to a sufficient value by varying the width of the control pulse 20. Further, the amount of ozone generated is controlled by changing the oscillation period, that is, the frequency, of the oscillation circuit 15 in accordance with the input to the setting terminal 14 to generate the reference pulse 19.

Although FIG. 5 shows another embodiment, it is basically the same as the embodiment shown in FIG. A computing unit 23 is provided, and the amount of ozone generated can be automatically controlled based on the current detection value of a current detector 24.

In addition, in the present invention, the high voltage coil is connected to the primary winding and the secondary winding.
Although the next winding is shown as an independent winding, it may be divided into one winding and connected. Also, unlike a step-up transformer, since it is a DC coil, an open magnetic circuit is used to avoid eccentric magnetization of the iron core, and the action of the iron core is divided between primary and secondary.
It is desirable to use it as a combination of secondary coils.

[Effects of the Invention] According to the present invention, since a simple DC chopper circuit is used as a power source instead of a symmetrical AC voltage source, the main circuit and control circuit can be extremely simple, and the drawbacks of the prior art are eliminated. In addition, since a high-voltage coil with an open core is used instead of a step-up transformer, the structure is simple and can be significantly downsized. In other words, it uses a frequency-variable chopping circuit and a high-voltage coil to simplify the design, making it easy to generate the required amount of ozone, and it is significantly smaller and less expensive than conventional models. can get.

[Brief explanation of drawings]

Fig. 1 is a single line diagram of a conventional power supply, Fig. 2 is a voltage and current waveform in a conventional power supply, Fig. 3 is an embodiment of the present invention, Fig. 4 is an explanatory diagram of its operation, and Fig. 5 is a different one of the present invention. This is an example. 12... Rectifier, 13... Smoothing capacitor, 1
5...Oscillation circuit, 16...Pulse circuit, 17...
Transistor, 18... DC high voltage coil, 23...
...Comparison calculator, 24...Current detector.

Claims (1)

[Claims] 1. In an ozone generator using silent discharge, the ozone generator and the high-voltage winding of a DC high-voltage coil are connected, and the low-voltage winding of the DC high-voltage coil and at least one switching element are connected in series with the DC power source. The switching element is periodically made conductive for a certain period of time to supply current to the low voltage winding of the DC high voltage coil, and when the current is cut off, resonance vibration is generated between the capacitance of the ozone generator and the DC voltage coil. An ozone generator characterized by inducing a voltage and using it as an ozone generating voltage source.