JPH0460716B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to a static electricity source in which a DC high voltage is applied between an anode and a cathode that are arranged so as to have a capacitance with each other via water to be treated. Regarding electric water treatment equipment.

BACKGROUND ART As a conventional electrostatic water treatment device of this type, there is one proposed in, for example, Japanese Patent Publication No. 56-3794. This device saves power by repeatedly turning on and off a power source for generating a high DC voltage to obtain a pulsed high DC voltage.

Problems to be Solved by the Invention However, when such a pulsed DC high voltage is used, there is a problem that the water treatment capacity inevitably decreases. In other words, if a pulsed DC high voltage is applied to the anode and cathode,
It can be operated conveniently when the water treatment load is low, but since the on/off operation limits the power supply, it cannot be used when the water treatment load becomes high. The drawback is that it disappears. For example, devices that use such pulsed DC high voltages work well under low loads such as continuous treatment of cooling water flowing through the circulation path, but red water forms in the water tower and causes rapid damage. There is a problem that processing capacity is insufficient at times of high load, such as when water treatment is required.

In order to eliminate these drawbacks, it is sufficient to use a flat DC high voltage that does not become pulsed, but in that case, new problems arise in terms of safety measures.

In other words, normally, the anode to which high voltage is applied is placed in water covered with an insulating film, and the cathode is grounded, but the anode may become damaged due to the water treatment container being shunted or aging. If the insulating properties of the insulating film deteriorate, it is dangerous because there is a risk of electric shock. Additionally, if a large current flows to the high voltage side due to shortening or poor insulation, the electronic elements on the low voltage side may generate heat and rapidly deteriorate.
Some kind of countermeasure is necessary.

For this reason, the device disclosed in the above-mentioned Japanese Patent Publication No. 56-3794 deals with this by increasing the duty ratio of the high voltage pulse to reduce the power on the high voltage side. However, when using a flat DC high voltage, it is not possible to take safety measures such as adjusting the duty ratio.
That's a problem.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to solve these problems and to enable sufficient safety measures to be taken even when a flat DC high voltage is used.

Means for Solving the Problems In order to achieve the above object, the present invention includes: an oscillation circuit that generates a high-frequency low voltage; a transformer that boosts the output voltage of this oscillation circuit; a rectifier circuit that doubles the voltage and generates a high DC voltage; means for detecting the current flowing through the high voltage section; and reducing the oscillation frequency of the oscillation circuit when the current flowing through the high voltage section exceeds a certain value. The device is configured to have a means.

Function: With such a device, a flat DC high voltage is generated by the oscillation circuit, transformer, and rectifier circuit, and this is applied between the anode and cathode. By using such a flat DC high voltage, it is possible to treat water with high power, and even when the load of water treatment suddenly increases, it can be handled satisfactorily.

The current flowing through the high voltage section is detected by the detection means, and the value of this current increases if a short or insulation failure occurs. Therefore, when this current exceeds a certain value, the oscillation frequency of the oscillation circuit is lowered. As a result, the impedance of the capacitor in the rectifier circuit increases, and the voltage at the high voltage section automatically decreases in response to this, thereby taking safety measures.

Embodiment FIG. 1 is a circuit diagram of an electrostatic water treatment device according to an embodiment of the present invention. Here, 1 and 2 are connection terminals to the commercial power supply, and receive AC100V supply. Connection terminals 1 and 2 are connected to the primary side of a transformer 5 via a fuse 3 and a temperature fuse 4. For example, AC 16V appears on the secondary side of the transformer 5, and this secondary side is led to a voltage stabilizing circuit 7 via a full-wave rectifier circuit 6. 7a is a volume for adjusting the output voltage in the voltage stabilizing circuit 7.

An oscillation circuit 8 is connected to the output side of the voltage stabilizing circuit 7, and a transformer 9 is further connected to the output side of the oscillation circuit 8. The oscillation circuit 8 includes a resistor 10,
11, and the resistors 10, 11 and the coil of the transformer 9 constitute an R-L oscillation path. 1
2 and 13 are switching transistors for oscillation.

A rectifier circuit 31 is connected to the secondary side of the transformer 9, which has a capacitor 14 such as a ceramic capacitor and a diode 15, and rectifies the secondary side voltage by four times. The output side of the rectifier circuit 31 is connected to a high voltage terminal 32.
2 is connected to an anode (not shown).

A cathode terminal 16 is connected to a cathode (not shown) and is led to the gate of the thyristor 19 via a potential difference generating diode 17 and a current detecting resistor 18. A current detection section 29 configured at the connection point between these diodes 17 and resistors 18
is electrically connected to the connection point 33 between the resistors 10 and 11 in the oscillation circuit 8. Also, thyristor 1
A voltage corresponding to the load capacitance between the anode and the cathode is generated at the gate 9, and a voltage detection circuit 20 is provided to detect this generated voltage.
Also connected to the voltage detection circuit 20 is a light emitting diode 21 that lights up when the detected voltage falls below a certain value.

Another full-wave rectifier circuit 22 is connected to the secondary side of the transformer 5 in parallel with the full-wave rectifier circuit 6. Another voltage stabilizing circuit 23 capable of generating a constant voltage of is connected. 24 is a light emitting diode that functions as a pilot lamp. A flasher circuit 25 is provided on the output side of the voltage stabilization circuit 23.
is connected to the flasher circuit 25, and a light emitting diode 26 which functions as a warning lamp is further connected to the flasher circuit 25. This light emitting diode 26
In parallel with this, an external connection terminal 27 is provided which can be used to light up a lamp outside the machine. The thyristor 19 described above is provided between the light emitting diode 26 and the flasher circuit 25. 28 is a diode, and the current detection section 29
This is to always create a potential difference between the ground 30 and the ground 30.

In such a configuration, there is no connection between connection terminals 1 and 2.
When AC100V is supplied, for example, AC16V is generated on the secondary side of the transformer 5, and a direct current voltage of, for example, DC12V is produced by the full-wave rectifier circuit 6 and the voltage stabilization circuit 7. Then, the oscillation circuit 8 operates,
A high frequency voltage of about 25kHz is generated. This high frequency voltage is input to the transformer 9, and a high frequency high voltage is generated on the secondary side of the transformer 9. Then, this high frequency high voltage is further increased in voltage by passing through the rectifier circuit 13 and converted into direct current, and appears as an output at the high voltage terminal 32. The output voltage can be adjusted to approximately 4,700 volts depending on the increase or decrease of water load by adjusting the volume 7a.
It can be changed to an appropriate value within the range of ~7000V.

As a result, a flat DC high voltage appears between the high voltage terminal 32 and the cathode terminal 16, and this is applied to an anode and a cathode (not shown) to perform water treatment. By using a flat DC voltage in this way, high-power water treatment is possible, and even when the load for water treatment suddenly increases, such as when red water occurs in a water tower, it can be handled effectively. It becomes possible.

The load current is constantly detected by the diode 17 and the DC detection resistor 18. This detection signal is supplied from the current detection section 29 to the connection point 33,
By changing the base currents of the transistors 12 and 13, the oscillation frequency of the oscillation circuit 8 is changed within a range of about 25kHz to 15kHz.

In other words, for normal loads, the oscillation frequency should be approximately
Although it is set to 25 kHz, the impedance of the capacitor 14 is small at this time, and the required high voltage is output to the terminal 32.

Now, suppose that the load current increases due to insulation deterioration due to shortening, aging, etc., or sudden changes in the quality or amount of water to be treated, and the load current becomes larger than the set value of, for example, 3 mA. Then, the voltage of the current detection section 29 decreases and the current to the connection point 33 decreases accordingly, causing the transistors 12,
As the base current of 13 becomes smaller, the oscillation frequency decreases. As a result, the impedance of the capacitor 14 is reduced and the output voltage appearing at the high voltage terminal 32 is automatically dropped, providing a safety measure. FIG. 2 shows an example of the relationship between load current and output voltage.

When the voltage of the current detection section 29 decreases, the gate current of the thyristor 19 increases accordingly, and the thyristor 19 is turned on. As a result, the light emitting diode 26 lights up to indicate overload, but the flasher circuit 25 and thyristor 1
The light emitting diode 26 exhibits a blinking display due to the cooperative action with the light emitting diode 9. Further, a detection voltage corresponding to the capacity of the load of the high voltage section is inputted to the voltage detection circuit 20 at a value of approximately 0 to 3.6V. When this detection voltage falls below a certain value, it means that the high output voltage has decreased due to a decrease in the oscillation frequency, so the light emitting diode 21 is turned on to indicate this fact.

Effects of the Invention As described above, according to the present invention, since a flat DC high voltage is used, water treatment with high power is possible, and when the treatment load suddenly increases. But it can be handled well. Moreover, in the event of a short or insulation failure, the voltage at the high voltage section can be automatically reduced even though it uses a flat DC high voltage.
It becomes possible to take sufficient safety measures, preventing accidents such as electric shock, and also ensuring protection of circuit elements on the low voltage side. Furthermore, since the circuit elements on the low voltage side can be reliably protected in this way, the output voltage can be increased as much as possible.
Furthermore, since a flat DC high voltage is used as described above, water treatment can be carried out extremely efficiently.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an electrostatic water treatment device according to an embodiment of the present invention, and FIG. 2 is a diagram showing an example of the relationship between load current and output voltage in the same device. 8... Oscillation circuit, 9... Transformer, 14... Capacitor, 16... Cathode terminal, 17... Diode for generating potential difference, 18... Resistor for current detection, 29
... Current detection section, 31 ... Rectifier circuit, 32 ... High voltage terminal, 33 ... Connection point.

Claims (1)

[Scope of Claims] 1. An electrostatic water treatment device that applies a DC high voltage between an anode and a cathode that are arranged so as to have a capacitance with each other through the water to be treated, An oscillation circuit that generates a high-frequency low voltage; a transformer that boosts the output voltage of this oscillation circuit; a rectifier circuit that doubles the voltage of the high-frequency current from the transformer using a capacitor to generate a high DC voltage; An electrostatic water treatment device comprising: means for detecting a current flowing through the high-voltage section; and means for lowering the oscillation frequency of the oscillation circuit when the current flowing through the high-voltage section exceeds a certain value.