JP2710107B2 - DC power supply circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention is used for an electrolysis apparatus such as an electrolysis ozone generator or a plating apparatus, and is used for an output side of an electrolysis tank or the like when a main power supply is cut off such as during a power failure. The present invention relates to a DC power supply circuit capable of supplying a protection voltage and current to the electrolysis apparatus to protect the electrolysis apparatus.

(Prior art and its problems) A circuit using a rectifying element such as selenium or silicon as a DC power supply for electrolysis is known. However, these circuits have no electromotive force when the power is cut off, such as during a power outage, and the plus and minus poles on the side to which power is supplied are electrically connected, such as for water electrolysis and plating. In the power supply circuit, the electrolytic cell side becomes a battery, and a reverse current flows through the circuit to cause deterioration of the electrodes, in particular, deactivation of the electrode active material coated thereon, and also adversely affect the DC power supply circuit itself. ing. Further, depending on the type of the electrolytic cell, it is necessary to always supply a protection current. In this case, it is necessary to change the connection to another circuit.

For example, for the purpose of preventing the reverse current, a secondary device of the DC power supply may be connected to a rectifying element for blocking a reverse current generated in response to a power failure, or an additional facility having a function of physically shutting off the power supply. We are setting up. In addition, in order to generate a protection current for protecting the electrolytic cell and the like from the reverse current, it is necessary to prepare a secondary battery in advance, and to connect the secondary battery to a circuit when the power shutoff is detected. . Although a device for automatically detecting the power interruption of the work and connecting the secondary battery has been developed, there is a problem that a time delay occurs and the device becomes complicated. The secondary battery used must always be charged, but for that purpose another power supply must be prepared, which not only complicates the device itself but also impairs the workability. is there. Although it is possible to use a rectifier power supply in order to eliminate the inconvenience caused by the reverse current, there is a disadvantage that a means for switching the connection is required similarly to the above-described device.

(Object of the Invention) The present invention has been made in order to solve the above problems, and to provide a simple DC power supply circuit having a structure capable of automatically supplying a protection current to an output side when power is cut off. With the goal.

(Means for Solving the Problems) The present invention relates to a DC power supply circuit having a transformer, a rectifier for rectifying AC current from the transformer, and an output-side electrolytic cell operated by DC current rectified by the rectifier. A dc power supply circuit, comprising: connecting a secondary battery having a voltage lower than the rectifier voltage in parallel with the rectifier, charging the secondary battery with the rectifier voltage, and supplying current to the electrolytic cell. A constant voltage diode may be connected to the circuit in series with the rectifier and the secondary battery.

 Hereinafter, the present invention will be described in detail.

As described later, the current value flowing through the electrolytic cell in the electrolytic reaction is not proportional to the voltage, and the voltage change accompanying the current change is quite small. For example, by reducing the voltage value by 20 to 30%, the current value becomes 100% Often decreases to about one degree.

The present invention intends to protect the electrodes of the electrolytic cell by supplying a protective voltage / current to the electrolytic cell by a secondary battery as an auxiliary power supply when the main power is cut off at the time of a power failure or the like by utilizing this phenomenon. .

The voltage V in a normal electrolyzer is represented by V = V ₁ (decomposition voltage) + V ₂ (overvoltage) + iR (electrolytic resistance). Formula in decomposition voltage is constant in the same electrolyte system, overvoltages are particularly Yin poles together about 100 mV / decade, the difference of about 200mV be changed current density from 1A / dm ² to 100A / dm ² is there. The electrolytic resistance is directly proportional to the DC current value, and most of the cell voltage fluctuation accompanying the current fluctuation is based on the voltage due to the electrolytic resistance.

For example, in the case of the SPE-type water electrolysis device, although depending on the type of the SPE material, the voltage value based on the electrolytic resistance is about 0.5 to 1 V in the trade name Nafion, which is a sulfonic acid-based cation exchange membrane, and is about 0 A / dm. The voltage change when changing the current from ² to 100 A / dm ² is about 1V. That is, in the electrolysis apparatus, the current value is not directly proportional to the voltage value, and even if the current value fluctuates greatly, the corresponding voltage value change is small. For example, the decomposition voltage than water electrolysis apparatus as the cathode platinum was lead dioxide electrode as the anode is approximately 1.24V, the overvoltage is about 0.8 V, 100A / dm further electrolytic resistance of about 1V is applied to cell voltage in the electrolysis of ² Is about
3V. If the cell voltage is reduced by 1V from 3V to about 2V, the current value becomes 1/100 or less, but the positive / negative direction does not change.

When this is applied to the present invention having the above configuration, when the main power supply is cut off and the voltage from the transformer applied to the rectifier becomes zero, a voltage about 1 V smaller than the rectifier voltage is applied to the electrolytic cell. When this is possible, a current in the same direction as about one-hundredth of the current for causing a normal electrolytic reaction flows in the electrolytic cell, and the electrolytic reaction stops, but the protection voltage current flows and the reverse direction occurs. The deterioration of the electrode, particularly the electrode active material coated on the electrode, due to the generation of electric current is effectively prevented.

In order to configure such a circuit, in the present invention, the rectifier and the secondary battery are connected in parallel, and the voltage of the secondary battery is made smaller than the rectifier voltage, for example, about 1V. When the DC power supply circuit connected in this way is energized, an AC voltage from a transformer is converted into a DC voltage by the rectifier, and the DC voltage causes a current to flow through the electrolytic cell to cause a predetermined electrolytic reaction. The secondary battery connected in parallel to the rectifier is charged. In general, a voltage difference of about 1 V has a low possibility of overcharging the secondary battery, but a circuit for preventing the overcharge may be formed.

As a result, when the current from the transformer is interrupted due to a power failure or the like, a reverse current is applied to the electrolytic cell by applying a voltage about 1 V lower than normal to the electrolytic cell from the charged secondary battery as described above. It is possible to prevent the current from flowing and to allow an extremely small protection current to flow.

In general, when the voltage from the rectifier power supply and the secondary battery is supplied to the electrolyzer, it is extremely rare that the supply voltage completely matches the electrolysis voltage of the electrolyzer. Depending on the situation on the voltage device side, it is often necessary to reserve an excess voltage. In other words, it is preferable to erase the difference between the voltage from any one of the power supplies and the electrolytic voltage by some method. For this purpose, the present invention uses a constant voltage diode such as a silicon dropper, a resistor, or the like. be able to. The silicon dropper has a feature of generating a voltage drop of about 0.6 V independently of a current value, and is preferably used to minimize a voltage change due to current proportionality. The amount of electrolysis current can be adjusted by increasing or decreasing the number of. Note that a variable resistor may be connected in series for minute current adjustment.

The accompanying drawings are circuit diagrams showing an example of the DC power supply circuit of the present invention.

Figure TR is transformer, 1 rectifier for converting alternating current from the transformer TR to a DC, R ₁ is a resistance connected to the rectifier 1, the variable R ₂ is connected to the resistor R ₁ The resistor R ₃ is a variable resistor connected to the resistor R ₂ , and the variable resistors R ₂ and R ₃ can be connected and disconnected by a switch, and can change the amount of current flowing through an electrolytic device described later. I can do it. CD is a silicon dropper connected to said variable resistance R _3, Z is an electrolytic device connected to the silicon dropper CD, electrolytic apparatus 2 is connected to the rectifier TR. BT is the variable resistor R ₂
And a secondary battery connected to a connection for connecting the connection between the electrolyzer and between connections 2 and the rectifier 1 between R _3.

When a voltage is applied to the circuit having the above configuration from a normal outlet or the like, the applied AC voltage is converted by the rectifier 1 into a DC voltage that is preferably about 1 V higher than the voltage generated in the secondary battery BT, and the resistance R ₁ (In some cases, variable resistor R ₂
And R ₃ ), a voltage drop is generated by the silicon dropper CD, and a voltage substantially equal to a desired electrolysis voltage is applied to the electrolysis apparatus 2 [current path is 1 → R ₁ (→
R ₂ → R ₃ ) → CD → 2 → 1], and an electrolytic product can be obtained by a predetermined electrolytic reaction. At the same time as applying a voltage to the electrolysis device 2, the voltage of the rectifier 1 charges the parallel-connected secondary batteries having a lower voltage than the rectifier 1 voltage. Thereby, for example, when the application of the voltage from the transformer TR is stopped due to a power failure, a voltage lower by about 1 V than the voltage of the rectifier 1 due to the electromotive force of the charged secondary battery BT is applied to the electrolysis device 2. [Current path is BT →
(R ₃ →) CD → 2 → BT], a small protection current of about 1/100 is passed through the electrolyzer 2 in the same direction as in the normal case, and the electrolyzer 2 and especially the electrodes of the electrolyzer 2 are used during a power failure. Effectively suppresses the degradation of the active substance.

(Example) Hereinafter, an example of the present invention will be described, but the example does not limit the present invention.

Example Rectifier (silicon junction type diode), 3Ω resistor
R ₁ , variable resistance R ₂ and 0 to 50 which can be varied in the range of 0 to 5Ω
Range can vary a variable resistor R ₃ and the silicon dropper Omega, and later to the electrolytic cell, and DC shown in the accompanying drawings electromotive force at the time of charging in a non-charging using lead sulfate type secondary battery which is 13.5V A power supply circuit was configured. The electrolytic cell has β-lead dioxide having an area of 3 cm ² on both sides thereof (anode side).
And an ion exchange membrane (Nafion # 117) on which a platinum (cathode side) layer is formed, and a volume of 300 ml filled with ion exchange water
Electrolytic cell.

An AC voltage is applied to the circuit by a plug from a laboratory outlet so that the rectifier voltage becomes about 14.5 V,
The voltage was applied to the electrolytic cell to produce ozone by electrolysis of ion-exchanged water.

Electrolysis voltage during electrolysis is 10.3 to 10.7 V, current density is 90 to 110
A / dm ² and oxygen gas containing 10% ozone in the anode compartment was obtained at a rate of 0.6 l / h.

After 24 hours, when the plug was pulled out from the outlet, the generation of oxygen gas was stopped and the current density was 1.5 to 2.5.
Although it decreased to A / dm ² , the direction of the current was the same as in the electrolysis.

(Effect of the Invention) In the present invention, a rectifier and a secondary battery are connected in parallel to a DC power supply circuit used for an electrolytic reaction, and the voltage of the secondary battery is lower than the voltage of the rectifier.

Therefore, during a normal electrolytic reaction, the rectifier voltage is applied to an electrolytic device that performs the electrolytic reaction to obtain a desired electrolysis product, and when the secondary battery is insufficiently charged, the secondary battery is charged. I do.

When the voltage application from the rectifier to the electrolytic device stops due to a power failure or the like, the charged secondary battery operates to apply a voltage lower than the rectifier voltage to the electrolytic device, preferably approximately 1 V, to the electrolytic device. I do. As a result, the amount of current flowing in the electrolysis device is extremely reduced, and the protection voltage current is insufficient to continue the electrolytic reaction but sufficient to prevent the deterioration of the electrodes and the like due to the reverse current flowing. And the inconvenience that tends to occur in the electrolysis apparatus when a rectifier voltage is not applied at the time of a power failure or the like is eliminated.

Further, by connecting a constant voltage diode or a resistor in series with the rectifier and the secondary battery, it is possible to more easily adjust the electrolytic voltage and the current.

Further, it is not essential to provide an additional circuit for charging the secondary battery, and by omitting the circuit, it is possible to reduce the size of the entire circuit and the number of circuit elements.

[Brief description of the drawings]

The accompanying drawings are circuit diagrams illustrating an example of a DC power supply circuit according to the present invention. 1 Rectifier 2 Electrolyzer TR Transformer R ₁ Resistance R ₂ R ₃ Variable resistance CD Silicon dropper BT Secondary battery

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-54-28234 (JP, A) JP-A-63-88047 (JP, U)

Claims (2)

(57) [Claims] 1. A DC power supply circuit comprising a transformer, a rectifier for rectifying an AC current from the transformer, and an output electrolytic cell operated by the DC current rectified by the rectifier, wherein a rectifier voltage is controlled in parallel with the rectifier. A DC power supply circuit, comprising connecting a secondary battery having a low voltage, charging the secondary battery with the rectifier voltage, and supplying current to the electrolytic cell. 2. A DC power supply circuit comprising a transformer, a rectifier for rectifying an AC current from the transformer, and an output-side electrolytic cell operated by the DC current rectified by the rectifier. Connecting a secondary battery having a low voltage and connecting a constant voltage diode in series with the rectifier and the secondary battery, charging the secondary battery with the rectifier voltage and supplying current to the electrolytic cell. Characteristic DC power supply circuit.