JP2003200163A - Electrolytic water making method and eletrolytic water making apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately control the dropping of electrolytic voltage by detecting an overcurrent, in controlling the electrolytic voltage applied to an electrolytic cell according to the measuring result of the pH value of electrolytic water due to a pH meter. <P>SOLUTION: The electrolytic voltage applied to the electrolytic cell according to the measuring result of the pH value of electrolytic water due to the pH meter is controlled. At this time, control for gradually dropping electrolytic voltage is performed in relation to the detection of a current exceeding an upper limit current value preset with respect to the current applied to the electrolytic cell and, in this control, the output interval of the indication of the voltage drop to a power supply part is matched with the voltage drop speed of the power supply part. Since the indication of the voltage drop to the power supply part is outputted according to the response speed of the power supply part, the drop of electrolytic voltage is performed according to the detected pH value. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing electrolyzed water and an electrolyzed water producing apparatus for electrolyzing tap water or the like to continuously produce alkaline ionized water and acidic ionized water.

[0002]

2. Description of the Related Art Conventionally, an electrolyzed water producing apparatus as shown in FIG. 13 has been provided. This is a filter medium 31 made of activated carbon.
Water purifier 3 provided with a filter medium 32 formed of a hollow fiber membrane
And an electrolytic bath 2, and two types of electrodes 21, 22 are arranged in the electrolytic bath 2 in a state of being partitioned by an electrolytic diaphragm 20.

The water sent to the water purifier 3 from the switching unit 98 attached to the tap water faucet 99 is purified in the water purifier 3, and then electrolysis in which a DC voltage is applied to the electrodes 21 and 22. The alkaline ionized water is sent to the bath 2 and, on the side of the electrode serving as the cathode, the alkaline ionized water
Acidic ionized water is generated on the side of the electrode serving as the anode.
Of these two types of ionized water, the main use water (generally, alkaline ionized water used for beverages) is sent out from the discharge port 23, and the sub-use water (acidic ion water) is sent from the discharge port 24 to the drainage port 64. To be

The voltage application to the electrodes 21, 22 of the electrolytic cell 2 is started by a pressure detection switch PS having a diaphragm 68 installed in a water channel connecting the switching unit 98 and the water purifier 3. Further, the water channel connecting the water purifier 3 and the electrolysis tank 2 is also connected to the drain port 64, but since the ball valve 66 is closed by the water pressure, the water going to the electrolysis tank 2 goes to the drain port 64. There is no direct flow.

When the water supply from the switching unit 98 is stopped, the pressure detecting switch PS is turned off and the electrolytic cell 2
The electricity to the electrodes 21 and 22 is cut off, and the water in the electrolytic cell 2 is discharged to the drain port 64 through the ball valve 66 which is open because there is no water pressure difference between the front and the back. Here, in the above, in order to confirm the pH value of the electrolyzed water that is actually discharged, a simple analysis with a reagent or the like must be separately performed, and in order to obtain electrolyzed water of the desired pH value. In addition, you have to manually adjust the set voltage and flow rate, including the time and effort required to check the pH value.
It was not possible to reliably obtain the electrolyzed water having the required pH value.

Therefore, a pH sensor for continuously measuring the pH value of the electrolyzed water to be discharged is provided, and the pH value obtained from this pH sensor is compared with the target pH value to apply the electrolysis voltage to the electrolytic cell. What has been proposed to feedback control is proposed. In such feedback control, in order to prevent excessive heat generation of the power supply unit, when a current exceeding the preset upper limit current value of the current supplied to the electrolytic cell is detected, the electrolytic voltage is applied to the power supply unit. It is usual to output an instruction for gradually lowering.

[0007]

[Patent Document 1] JP-A-6-343959

[0008]

However, in the conventional device, the response speed for the voltage drop in the power supply unit cannot follow the output timing of the instruction for the voltage drop to the power supply unit, and the overcurrent detection is canceled. At that time, the power supply unit was instructed to lower the electrolytic voltage to an unnecessary value, and as a result, it was not allowed to flow current up to the upper limit current value set for this, and feedback control was performed. Sometimes it was incomplete.

The present invention has been made in view of the above points, and an object of the present invention is to provide an electrolyzed water producing method capable of accurately controlling the drop of the electrolysis voltage by detecting an overcurrent. .

[0010]

SUMMARY OF THE INVENTION The method for producing electrolyzed water according to the present invention, however, produces a pH value in generating alkaline ionized water and acidic ionized water by electrolysis in an electrolyzer and discharging the electrolyzed water separately. In the method of producing electrolyzed water in which the electrolysis voltage applied to the electrolyzer is controlled according to the measurement result of the pH value of electrolyzed water by the sensor, for detection of a current exceeding the preset upper limit current value for the energizing current to the electrolyzer Along with performing control to gradually lower the electrolytic voltage, the control is characterized in that the output interval of the voltage drop instruction to the power supply unit is adjusted to the voltage drop speed of the power supply unit,
The electrolyzed water producing apparatus according to the present invention is an electrolyzed water producing apparatus that produces alkaline ionized water and acidic ionized water by electrolysis in an electrolyzer and discharges these electrolyzed water separately, wherein A pH sensor for measurement and a control circuit for controlling the electrolysis voltage applied to the electrolytic cell according to the result of measuring the pH value of the electrolyzed water by the pH sensor are provided, and the upper limit current value preset for the energizing current to the electrolytic cell The above control circuit, which performs control to gradually lower the electrolytic voltage in response to the detection of a current exceeding 1.0, adjusts the output interval of the voltage drop instruction to the power supply unit to the voltage drop speed of the power supply unit when gradually decreasing the electrolytic voltage. It is characterized by being present.

Since the voltage drop instruction to the power supply unit is output according to the response speed of the power supply unit, the electrolytic voltage drop is made according to the detected pH value.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below based on an example of an embodiment.
As shown in FIG. 3, it is assumed that the electrolytic cell 2, the backwash unit 4, the switching valves 5 and 6, the flow rate adjusting valve 65, the pH sensor 7, the calcium agent adding cylinder 80, etc. are housed in a housing (not shown). It is configured.

Like the conventional example, the electrolytic cell 2 is provided with two kinds of electrodes 21, 22 and an electrolytic diaphragm 20 for partitioning the two, and has inlets 25, 26 on the bottom side and discharges on the upper side. Equipped with outlets 23, 24, these outlets 23, 24
Are connected to the discharge pipes 17 and 18 via the switching valve 6.

Here, the inflow port 25 and the discharge port 23 communicate with the space surrounding the one electrode 21, and the inflow port 26 and the discharge port 24 communicate with the space surrounding the other electrode 22. The inflow port 25 is thinner than the inflow port 26 so that the flow rate flowing into the electrode 21 side is smaller than the flow rate flowing into the electrode 22 side at a ratio of 1: 3 to 1: 4. The switching valve 6 connects the discharge port 23 and the discharge pipe 17 with each other, connects the discharge port 24 and the discharge pipe 18 with each other, and connects the discharge port 23 and the discharge pipe 18 with each other.
It is composed of an electromagnetic rotary valve or a motor type switching valve that connects the discharge port 24 and the discharge pipe 17 to each other.

The water purifier 3 is provided with a filter medium 31 made of activated carbon and a filter medium 32 made of a hollow fiber membrane, and one of the two openings provided at the lower end of the filter medium 31 is provided in the backwash unit 4. The other is connected to the switching valve 5. The above two types of filter media 31 and 32 are contained in a single cartridge, and the cartridges can be replaced together.

The backwash unit 4 is a filter medium 3 in the water purifier 3.
It is for eliminating the clogging of 1, 32 by performing backwashing in which the purified water filtered by once passing through the water purifier 3 is back-flushed to the water purifier 3. As shown in FIG. The cylinder 41 includes a piston 41 arranged in the cylinder 40, and an interlocking pin 42 slidably engaged with the piston 41 and pulling down the valve body 43 against the spring 45 as the piston 41 descends.
A port 46 connected to the water purifier 3 and a discharge port 44 that opens when the valve body 43 descends and closes when the valve body 43 rises are provided at the upper end of the cylinder, and the space below the piston 41 in the cylinder 40 is It communicates with the port 55 of the switching valve 5 described below.

The switching valve 5 mounted below the backwash unit 4 has ports 51 and 54 at both ends and three ports 52, 53 and 55 at axially offset positions on the circumferential surface. By moving the built-in movable body 56 by the water pressure of the water selectively flowing in from the ports 51, 54, the ports 51, 52 shown in FIG. 4 communicate with each other, and the ports 55, 53 form the outer periphery of the movable body 56. The state in which communication is performed through the space 57 and the state in which the movable body 56 moves to the right in the figure to communicate between the ports 54 and 55 and the state in which communication is performed between the ports 52 and 53 through the outer peripheral space 57 are switched.

The port 52 is connected to the water purifier 3 and the port 53 is connected to the drain pipe 19. Further, the ports 51 and 54 are connected to a switching unit 98 provided on the faucet 99, and a flow rate adjusting valve 65 is provided between the port 51 and the switching unit 98. Constant flow valve 6 arranged between the port 52 and the water purifier 3
4 is provided in order to prevent excess water pressure from being applied to the water passage after the water purifier 3. Also, ports 51, 5
The pipe connecting the switch 4 and the switching unit 98 is in contact with the lower surface of the power supply box 70 containing the power supply through the heat dissipation plate in the body of the electrolyzed water generator, and the contact portion is copper. It is made of metal such as aluminum or aluminum. The water supplied to the power supply unit can be cooled to increase the safety of the power supply unit against heat generation.

The discharge port 44 of the backwash unit 4
Is connected to the inflow ports 25 and 26 of the electrolytic cell 2 by a pipe 47. A flow meter 66, a check valve 67 and a solenoid valve 63 are provided in the middle of the pipe 47.
Among the pipes that individually connect the solenoid valve 63 and the inlets 25 and 26, the calcium agent addition cylinder 80 is provided in the middle of the pipe 48 that reaches the inlet 25. The check valve 67 is connected to the drainage port 19 and is closed when water pressure is applied to the pipe 47 side, but is opened when water pressure is not applied to the pipe 47 side, and the check valve 67 inside the electrolytic cell 2 is closed. The water and the water in the pipe 47 are discharged from the drain port 19.

A pH sensor 7 is provided in the middle of the discharge pipe 18.
Is provided. As shown in FIG. 5, the pH sensor 7 is composed of a reference electrode portion including a saturated KCl or NaCl solution and a silver-silver chloride electrode, and a working electrode portion including a saturated KCl solution and a special glass electrode. By amplifying the electromotive force generated between both electrodes in proportion to the hydrogen ion concentration of the ionized water to be measured, as shown in FIG. It is configured to output a voltage, and this output voltage is A / D
After the conversion, it is taken into the control circuit C described later.

The electrolyzed water generator thus formed is
As described above, the two ports 5 in the switching valve 5
1, 54 are connected to the switching unit 98 via individual pipes. The switching unit 98 is configured to be able to switch between stopping water supply to the electrolyzed water generator, supplying water to the port 51 side, and supplying water to the port 54 side by operating a lever. .

Next, the flow of water at the time of taking out the electrolyzed water will be described. In the switching unit 98, if the water is made to flow to the port 51 side of the switching valve 5, the water reaching the port 51 of the switching valve 5 will be Movable body 56 in switching valve 5 by water pressure
2, the water purifier 3 enters from the port 52, is filtered by the filter media 30 and 31, and then reaches the port 46 of the backwash unit 4. Then, the water that has entered the cylinder 40 of the backwash unit 4 from the port 46 first pushes down the piston 41 by the water pressure, opens the discharge port 44 that was closed by the valve body 43 until then, and from this discharge port 44 to the pipe 47. Through the inlet 25 of the electrolytic cell 2,
It enters into the electrolytic bath 2 from 26 and is electrolyzed there. In addition,
The energization of the electrolytic cell 2 is started based on the flow rate information obtained from the flow meter 66 arranged in the middle of the pipe 47.

If there is an instruction to obtain alkaline ionized water, the electrode 21 of the electrolytic cell 2 serves as the anode,
Since the electrolytic voltage is applied so that the electrode 22 serves as the cathode, acidic ionized water is obtained at the ejection port 23 side and alkaline ionized water is obtained at the ejection port 24 side. At this time, the switching valve 6 is shown in FIG. Because of the state, the alkaline ionized water is discharged to the discharge pipe 18 side and the acidic ionized water is discharged to the discharge pipe 17 side.

When it is instructed to obtain acidic ionized water, there are the following two water streams depending on the instructed acidity. First, in the case of weakly acidic ionized water, electrolyzer 2
Since the electrolytic voltage is applied so that the electrode 21 of FIG. 2 serves as a cathode and the electrode 22 serves as an anode, alkaline ionized water is obtained at the ejection port 23 side and acidic ionized water is obtained at the ejection port 24 side. Since the valve 6 is the same as in the above state, the alkaline ionized water is discharged to the discharge pipe 17 side and the acidic ionized water is discharged to the discharge pipe 18 side.

In the case of strong acidic ionized water, an electrolytic voltage is applied so that the electrode 21 of the electrolytic cell 2 serves as an anode and the electrode 22 serves as a cathode, so that the acidic ionized water is discharged to the discharge port 23 side.
Alkaline ionized water is obtained on the side of the discharge port 24. At this time, the switching valve 6 is switched to a state different from the above two states as shown in FIG.
Side, the acidic ionized water is discharged to the discharge pipe 18 side. As described above, when the strongly acidic ionized water is discharged from the discharge pipe 18 side, the electrode 21 side serves as the anode as described above.
This is because the inflow port 25 to the electrode 21 side is narrowed down from the inflow port 26 on the electrode 22 side to reduce the inflow amount, so that it is easy to obtain the strongly acidic ionized water.

Then, in the switching unit 98, if the water is made to flow to the port 54 side of the switching valve 5, the switching valve 5 is switched by the movement of the movable body 56 by the water pressure, and the water entering from the port 54 passes through the port 55. It flows into the space below the piston 41 in the backwash unit 4, pushes up the piston 41, closes the discharge port 44 with the valve body 43, and the filtered purified water accumulated in the space above the piston 41 from the port 46 through the water purifier. Back flow to side 3. The backflow water backwashes the filter media 32 and 31 to wash away the impurities adhering to the filter media 32 and 31, and then the ports 52 of the switching valve 5
It is discharged from the drain port 19 via 53. The inflow of water from the switching unit 98 at this time ends when the piston 41 in the backwash unit 4 is moved to the top dead center. Then, during such backwashing, the switching unit 98
When the water is stopped in the water, the water in the electrolytic cell 2 passes through the check valve 67, which is in the open state because there is no water pressure difference, and then the drain port 1
Emitted from 9.

FIG. 1 is a block circuit diagram of the electrolyzed water producing apparatus, in which C is the control circuit constituted by a one-chip microcomputer, DV is a power source section for outputting an electrolysis voltage, and D is an operation display. It is a department. pH sensor 7
The control circuit C to which the flowmeter 66 and the flowmeter 66 are connected is the electrolytic cell 2
The electrolysis voltage applied to the electrodes 21, 22 of the power source unit DV is configured to be controllable by PWM control of the power source unit DV, and the target pH value and the discharge pipe 18 obtained from the pH sensor 7 are being discharged. A built-in comparison circuit C1 with the pH value of the electrolyzed water is provided, and feedback control of the electrolysis voltage is performed so that the detected pH value matches the target pH value.

The comparator CP, to which the voltage across the resistor R having a low resistance value inserted in the power source section DV is input, compares the magnitude of the energizing current with the upper limit value according to the voltage drop in the resistor R. When the energized current exceeds the upper limit value specified according to the voltage applied to the electrodes 21 and 22, an overcurrent detection signal is output to the control circuit C, and the control circuit C that receives this outputs the overcurrent detection signal. A voltage drop instruction signal is output to the power supply unit DV so that the voltage applied to the electrodes 21 and 22 becomes low. The power source unit DV is prevented from generating excessive heat.

FIG. 6 shows an example of the display operation section D. As the operation unit, in addition to the power switch SW ₁ , pH changeover switches SW ₂ , SW ₃ , SW ₄ , reset switches SW ₅ , p
In addition to having a switch SW ₇ for finely adjusting H, a switch SW ₉ for turning on and off to indicate by sound that electrolysis is in operation, resetting the cumulative use time of the water purifier 3 accumulated in the control circuit C Switch SW ₁₀ and life setting S
W ₁₁ , a switch SW ₁₂ for cleaning the pH sensor 7,
It has SW ₁₃ .

The turning off of the notification means by the switch SW ₉ is effective only when the alkaline ionized water is discharged from the discharge pipe 18. That is, when the acidic ionized water is discharged from the discharge pipe 18, the switch SW
_{Even if 9} is turned off, the warning means is activated to give a warning by a melody or a buzzer. This is to inform the user that the water currently being discharged is acidic ionized water and is not suitable for drinking. For the same reason, when the discharge state of acidic ionized water is switched to the discharge state of alkaline ionized water, the measured value by the pH sensor 7 is p.
Until H8 is exceeded, or at a predetermined flow rate (for example, 1
(000 ml) is discharged or a warning is kept sounding until a predetermined time elapses, and when the discharge state of acidic ionized water is switched to the discharge state of purified water, the pH sensor 7 does not output acidity. Alternatively, the alarm is kept sounding for 10 seconds or until a predetermined flow rate is discharged. Furthermore, the electrode 2
It is also preferable to sound a warning when switching to a discharge state of alkaline ionized water or purified water during reverse electrolysis cleaning of 1 and 22 described later.

The washing of the pH sensor 7 with the switches SW ₁₂ , SW ₁₃ is carried out to remove the scale deposited on the pH sensor 7. That is, in the case of alkaline ionized water having a pH of 10 or more, especially when the carbonic acid content is excessive, such as groundwater,
The abundance ratio of the carbonate ion CO ₃ ^{2− is} larger than that of the hydrogen carbonate ion HCO ₃ ⁻ , and in this case, the phenomenon of precipitation as calcium carbonate is increased. If the sensing portion of the pH sensor 7 is covered by the deposition of this scale, the sensing accuracy of the pH sensor 7 (particularly on the acidic side) is lowered and the rising response is deteriorated. The above cleaning is performed to address this point. Details will be described later.

As shown in FIG.
In addition, the pH value obtained by the pH sensor 7 is displayed on the display.
Display La for displaying numbers, the switch SW₂, S
W₃, SW _FourDisplay section Ld for displaying the selection state of₁~ Ld₇,
Display unit L that indicates that the electrodes 21, 22 are being cleaned
e, a display portion L that prompts replacement of the filter media 31, 32 of the water purifier 3
f, display section Lp for prompting cleaning of the pH sensor 7, power state
Display section L₁And so on.

The cleaning of the electrodes 21 and 22 whose operation is displayed by the display unit Le is to remove the scale generated on the electrodes 21 and 22, and when the water flow is detected by the flow meter 66, the electrolytic cell is washed. This is performed by applying a voltage of opposite polarity to the second electrodes 21 and 22 for a short time. However, since the electromagnetic valve 63 is closed at the start of this cleaning, the reverse electrostatic cleaning in the water retention system is performed. Done. At this time, the pH value on the anode side becomes strong acidity of about pH 2 by retaining water, so that the adhered calcium carbonate and magnesium carbonate components can be dissolved and removed. Further, in the latter stage of the reverse electrolysis cleaning, the solenoid valve 63 is opened, so that the reverse electrophoretic cleaning in the running water system is also performed, so that complete electrode cleaning can be expected. In addition, since the cleaning water containing scale contained in the electrolytic cell 2 is discharged from the inlets 25 and 26 through the drainage port 19 at the time of this cleaning, the cleaning water is not mixed at the time of the next use start.

[0034] Thus, in that an operation display unit D as described above, and the display unit L ₁ if power on switch SW ₁ is turned on, pressing the switch SW ₂ in this state,
With (level 4 in FIG labeled "strongly alkaline") level "water purification" or "1-4" in response can be selected to the number of times to press the display portion Ld ₃ is selected
~ Ld ₇ is displayed, and if water is sent through the switching unit 98, the selected operation is performed. "Purified water" that can be instructed by the switch SW ₃
When is selected, the display portion Ld ₃ is lit and displayed, and since the electrolytic voltage is not applied to the electrolytic cell 2, the water just purified by the water purifier 3 is discharged from the discharge pipe 18. The flow rate and pH value of water at this time are displayed on the display unit La.

When any one of the levels 1 to 4 of alkaline ionized water is selected, the application of the electrolytic voltage is started by sensing the water flow by the flow meter 66. At this time,
The control circuit C is a discharge pipe 18 obtained from the pH sensor 7.
Feedback control of the electrolysis voltage is performed so that the pH value of the electrolyzed water discharged from the device becomes a target pH value that is preset according to the selected level. The target pH value is, for example, pH 9.0 for level 1, pH 9.5 for level 2,
PH 10.0 for level 3 and p for level 4 (strong alkali)
A value such as H10.5 is set. The detected pH value is displayed numerically by the display unit La.

Switch SW_FourIf you press,
Therefore it can be used as astringent water
A display that indicates that weakly acidic ionized water has been selected.
Ld ₂Indicates that strong acidic ionized water has been selected
Display unit Ld₁And are lit up alternately and selected.
A target pH value is set according to the generated electrolytic strength. here
Then, for weakly acidic ionized water, set the target pH value to 5.8,
In the case of strongly acidic ionized water, set the target pH value to 3-2
The target pH value acidic ionized water is discharged to the discharge pipe 18.
Feedback control of the electrolytic voltage is performed.

The flow path for weakly acidic ionized water is shown in FIG.
As described above, the flow path in the case of strongly acidic ionized water is as shown in FIG. 3 as described above. By switching the flow in this manner, that is, the strongly acidic ionized water is obtained. The strongly acidic ionized water is easily obtained by reducing the flow rate flowing to the electrode 21 side.

Next, the details of the feedback control will be described. The feedback control is performed based on the following algorithm. That is, when the target pH value is pHM, as shown in FIG. 7, the application of the voltage Vm preset according to the target pH value is continued until the output obtained from the pH sensor 7 becomes stable. It should be noted that here, the state in which the fluctuation range is within ± 0.1 pH is continuous for 2 seconds is stable. Then, the pH value p at the above stable point
The deviation ΔpH between HA and the target pH value pHM is obtained, and the voltage Vn (Vn = Vm−Δ) corresponding to the deviation ΔpH is obtained from the voltage-pH (pH sensor output voltage) characteristic table shown in FIG.
V) is obtained and this voltage Vn is applied. Such correction of the applied voltage is performed every time the output obtained from the pH sensor 7 stabilizes until the deviation ΔpH falls within ± 0.2 pH. When the deviation ΔpH is within ± 0.2 pH, the applied voltage at that time is maintained as it is.

Due to the disturbance such as the change of flow rate, the pH
When the deviation ΔpH at the time when the value fluctuates and stabilizes exceeds ± 0.2 pH with respect to the target pH value, the voltage-pH
Obtaining the voltage corresponding to the deviation ΔpH from the characteristic table and applying this voltage is repeated until the deviation ΔpH is within ± 0.2 pH. When the feedback control is performed in this way, so-called overshoot hardly occurs, as can be inferred from the change in pH value shown in FIG. 7, and therefore the time required for convergence to the target pH value can be shortened. In particular, since the deviation ΔpH is obtained at the time when it becomes stable as described above, the applied voltage correction based on the deviation ΔpH is usually 1
This is all that is needed, and in this respect as well, the time required to converge to the target pH value is short.

Furthermore, when the target pH value is different, that is, when alkaline ionized water is desired, weakly acidic ionized water is desired, and strongly acidic ionized water is desired, side reactions during electrolysis are performed. Since there is a difference in the reaction time due to the difference (for example, the chlorine ion oxidation reaction), it is necessary to change the target pH value (here, in each generation mode of alkaline ionized water, weakly acidic ionized water, and strongly acidic ionized water). A voltage-pH characteristic table suitable for each is prepared, and feedback control is performed by a corresponding one. Curve A in FIG. 8 is for alkaline ionized water, B is for weakly acidic ionized water, and C is for strongly acidic ionized water. P for the voltage change of the target pH value
We are also performing control that is suitable for the rising characteristics of H changes, so that whatever the target pH value is, the pH value of the electrolyzed water to be discharged should converge to the target pH value early. Therefore, the electrolyzed water having the desired pH value can be obtained reliably and quickly. These voltage-pH characteristic tables (curves a, b, and c) are: pHv = A + Blog _e V (pHv is the pH sensor output voltage, V is the electrolysis voltage, A,
B can be represented by an approximate expression of a constant that is different for each mode).

By the way, in performing such feedback control, in order to prevent excessive heat generation of the power source section DV, when an electrolytic voltage at which a current exceeding a preset upper limit of the electrolytic cell current value flows is applied. Therefore, the control circuit C that has received the overcurrent detection signal normally outputs an instruction to decrease the electrolytic voltage by one step every predetermined time.

Here, the predetermined time is, for example, 8
In contrast to msec, the responsiveness of the power supply unit DV, which is the switching power supply instructed above, can only lower the output voltage by one step every 256 msec due to the influence of the capacitor in the output rectifier circuit. When,
When the control circuit C receives the signal for canceling the overcurrent detection, the switching power supply has instructed the switching power supply to lower the electrolytic voltage to an unnecessary value. No voltage can be applied, and as a result, electrolyzed water having a pH value far from the target pH value is discharged.

For this reason, the control circuit C, which has received the signal indicating that the electrolytic cell current has become an overcurrent, outputs a voltage drop instruction to the power source section DV in accordance with the voltage drop rate in the power source section DV. I am doing it. That is, the power supply unit D
If V can decrease the output voltage by one step every 256 msec, the control circuit C outputs an instruction to the power source unit DV for decreasing the output voltage by one step every 256 msec. . Therefore,
Also in the control in the case of overcurrent detection, an electrolytic voltage having a maximum upper limit current value can be applied without causing an overshoot. Needless to say, the next voltage drop instruction signal may be output after the output voltage drop of the power supply unit DV is confirmed.

Regarding overshoot prevention,
When electrolyzing a peculiar water such as groundwater that has a high conductivity and can easily carry an electric current, the following points must be noted. That is, in the case of obtaining weakly acidic ionized water from the above-mentioned water, in the case of the one shown in the above-mentioned example, 1 to 1
While it is possible to obtain ionic water having a pH of 4 to 6 at an electrolysis voltage of about 5V, general water requires an electrolysis voltage of about 30V. For this reason, in the astringent mode, based on the electrolytic voltage-pH characteristic formula preset for general water, the conductivity as described above is high and weak acidity is exhibited at a small applied voltage. When control is performed on water, as shown in FIG. 9 (a), the deviation Δ
Since the fluctuation width ΔV ₁ of the applied voltage with respect to pH is too large as compared with the fluctuation width ΔV ₂ which is actually required, an overshoot is caused and the displayed pH value fluctuates. In order to avoid this, here the deviation ΔpH
As shown in FIG. 9B, the fluctuation range ΔV ₁ of the applied voltage with respect to is smaller than the fluctuation range ΔV ₂ in the actual water characteristic curve e.

Further, here, when the stable state within a fluctuation of ± 0.1 pH continues for 10 seconds or more, the voltage value at this time and p
The H value and the H value are written in the memory of the control circuit C. The value written in this memory is referred to when the water is stopped once and then again passed, and this voltage value is immediately applied. The convergence time to the target pH value after resuming water flow becomes faster. The memory is rewritten every time the above conditions are satisfied. The preset voltage value may be rewritten for each target pH value.

By the way, since the water in the electrolysis tank 2 is drained when the water is stopped, even if water flow is started from this state, the electrolysis tank 2 is filled with water and further reaches the pH sensor 7. Takes time. Even when the target pH value is changed during the passage of water, it takes time for the water in the electrolytic cell 2 to be replaced to some extent. Therefore, immediately after the start of water flow, the pH
The output of the sensor 7 does not change, and such a time zone is called a dead zone (area indicated by K in FIG. 7).
If the above control is performed even in this dead zone, there is a possibility that a stable point for deriving the above-mentioned correction value may be detected when the ion water corresponding to the applied voltage has not reached the pH sensor 7. Therefore, the following dead zone processing is also performed in the feedback control.

That is, in the case where the water flow is started from the water-stopped state, as shown in FIG. 10, when the water flow is started, the application of the voltage Vm preset according to the target pH value is started and the pH is also started. Although the output of the sensor 7 is displayed, a predetermined time T1 (for example, 15
Until the second) elapses, the feedback control is not performed and the voltage Vm is maintained. Then, after the elapse of T1 time, it is judged whether the dead zone has escaped or not depending on whether the pH value has changed by 0.2 pH in the desired direction, and after the escape is confirmed, the above-mentioned stable point for 2 seconds and the target pH at that time are determined. The feedback control mode based on the deviation from the value and the voltage-pH characteristic table is entered.

When the target pH value is changed during the passage of water, the application of the voltage Vmn corresponding to the new target pH value is immediately started in response to the change and the output of the pH sensor 7 is displayed. However, a predetermined time T2 from the change
Until (for example, 3 seconds) elapses, the feedback control is not performed and the voltage Vmn is maintained. Then, after the lapse of T2 time, it is judged whether or not the dead zone is escaped depending on whether or not the pH value is changed by 0.2 pH in the intended direction,
After the escape is confirmed, the above feedback control mode is entered.

If the escape of the dead zone is judged only by whether or not the pH value has changed by 0.2 pH in the intended direction, the pH change may be slight by 0.2 p due to some cause.
When no change of H or more is observed, it is not possible to enter the feedback control mode, so it is desirable to add a judgment section for forced escape. The determination unit may be a timer in which a time longer than the predetermined times T1 and T2 is set, but, for example, when 0.2 liters of water is passed, it is forced to escape and enter the feedback control mode. In this case, if the feedback control mode is entered, it is preferable to perform pH comparison at that time without making a wait for the determination as to whether the stability is stable, and to make a correction.

By the way, when the acidic ionized water is discharged and the water used contains a large amount of carbonic acid components like groundwater, basic carbonates Ca (HCO ₃ ) ₂ , Mg are used.
(HCO ₃ ) ₂ , NaHCO _3, etc. are produced, but the pH
When weakly acidic ionized water of about 5.0 to 6.0 is discharged, if the pH value of the weakly acidic ionized water is detected by the pH sensor 7, the basic carbonate is weakly dissolved in the weakly acidic ionized water. Due to its alkaline nature, the pH value detected becomes alkaline, and when it becomes stable after water discharge, the carbonate H ₂ CO ₃ produced from the basic carbonate dissociates again. Therefore, there is a problem that it exhibits weak acidity. In other words, even if weakly acidic ionized water is obtained, the pH of the ionized water during discharge is checked.
Since the sensor 7 outputs the result of being alkaline, it means that ion water having a desired pH value cannot be obtained when the above feedback control is performed on water containing a large amount of carbonic acid components. Become.

For this reason, when weakly acidic ionized water is designated here, the pH value detected during control is pH 7.
If it exceeds 0, it is judged that it is groundwater with a large amount of carbonic acid components, and the pH display is forced to the set value (here, 5.8), and the ratio of 0.1pH / 0.5sec from the time of the above judgment. I am trying to make a transition.

More specifically, when groundwater having a high carbonic acid content is used for the production of weakly acidic ionized water, the results shown in FIG.
As shown in FIG. 1, when a certain constant voltage Va corresponding to the pH value of weakly acidic ionized water is continuously applied, the pH sensor 7
Indicates a value near the target pH value, but then 2
After about 30 seconds, the carbonate shows an alkaline value even though the actual pH value is 5.0 to 6.0.

For this reason, the pH sensor 7 has a pH of 7.0.
In order to surely perform the operation of determining whether or not to show the above, when the mode is changed from the water-stopped state to the weak acidic ionized water discharge mode, the predetermined time T described regarding the dead zone is given.
While the application of the preset voltage is started during the period of 1, the feedback control is not performed, and the output of the pH sensor 7 is displayed, but a predetermined time (for example, 2
It is assumed that the determination as to whether the pH exceeds 7.0 is not made until (0 seconds) has elapsed. This is because, as described above, it is not possible to determine whether or not it is reliable even if the pH exceeds 7.0 during the above time.

From the time when the above time has elapsed, the pH is
If the pH sensor 7 outputs a value exceeding 7.0,
It was determined that the water was groundwater, and the electrolysis voltage was fixed at the voltage at the time of determination, and the displayed value was 0.1 pH / 0.
Transfer at a rate of 5 seconds. When the pH does not exceed 7.0, it is determined that the city water is used, and the control is continued according to the electrolytic voltage-pH characteristic formula preset as described above. As the voltage-pH characteristic formula, an approximate formula of pHv = 2.5-αlog _e V (α: a constant that varies depending on the flow rate) is used.

When the discharge mode of the water having another pH value is switched to the discharge mode of the weakly acidic ionized water, the dead zone treatment at the time T1 is set to 15 seconds, and the rest state is changed to the discharge mode of the weakly acidic ionized water. Similar to the transition, the control is performed by determining whether the output from the pH sensor 7 exceeds pH 7.0. The above determination in the weakly acidic ionized water discharge mode is performed every time so that the variation in water quality can be dealt with.

Next, the cleaning of the pH sensor 7 will be described. In the feedback control using the pH sensor 7,
It is expected that the accuracy and the rising characteristic of the pH sensor 7 are always constant, but as described above, the deposition of the scale lowers the accuracy and also deteriorates the rising response. For this reason, the state of the pH sensor 7 is examined by the following processing.

That is, in the RAM in the control circuit C, p for the applied voltages V1 to V8 in the set flow rate range is set.
A reference table as shown in the following table describing the output voltage VSii of the H sensor 7 is stored. The value to be stored here is the value when the same electrolysis voltage is continuously output for a fixed time (for example, 30 seconds) or more during pH control when the reference table is empty after passing a required flow rate (for example, 300 liters) of water. The electrolysis voltage and the output voltage VSii of the pH sensor 7 at that time are written in the corresponding columns. The dead times T1 and T2 for processing the dead zone are not included in the count of the fixed time.

[0058]

[Table 1]

In this way, after sequentially writing in the columns satisfying the conditions, the integrated flow rate is 1000 to 2
When it reaches 000 liters, the contents of the reference table and the current output voltage of the pH sensor 7 are compared with each other. It should be noted that no comparison is made in the empty space in the reference table. In addition, writing to a vacant place is performed even after the comparison is started. By comparison, when the output voltage of the pH sensor 7 at a certain flow rate range and a certain electrolytic voltage at the present time deviates from the electrolytic voltage VSii in the corresponding column on the reference table by a predetermined value, for example, acidic ions + 0.3V when discharging water, ± 0.3V when discharging alkaline ionized water
When V is off, the display unit Lp is turned on to turn on the pH sensor 7
Encourage cleaning.

The cleaning of the pH sensor 7 is performed by the switch S.
W₁₂, SW₁₃Either (switch SW₁₂Encourage cleaning
The switch can be operated only when the display Lp is lit.
SW ₁₃Can be operated even when the display Lp is not lit
The solenoid valve 63 is closed and the switching valve is pressed.
6 is switched to the state shown in FIG. 3, and the discharge pipe 1
After plugging 7, plug the calcium addition cylinder 80
Pour a specified amount of acid solution and leave for 1 hour or several hours in this state.
It is done by leaving it for a while. Through the electrolytic cell 2 and the switching valve 6
The citric acid solution that reaches the pH sensor 7 by the
-Dissolve the scale adhering to 7. of course,
Adhered in the flow path from the electrolytic cell 2 to the pH sensor 7
Also dissolve the scale. After leaving the above, for example,
Just pass water for several tens of seconds to several minutes in purified water output mode
So, because citric acid has a very high solubility, wash it off.
Can be stored. It is the above that the discharge pipe 17 is plugged.
Discharge pipe of citric acid solution by the siphon principle while left unattended
This is to prevent it from flowing out from 7. Calciu
Inject the citric acid solution from the cylinder 8
It is good to push in using equipment.

Powdered citric acid may be used.
In this case, the solenoid valve 63 is of a type that can supply water from the water purifier 3 side to the electrolysis tank 2 side even when the solenoid valve 63 is closed.
Operation of the switching unit 98 of about 30 seconds (500-10
Water (00 ml) to dissolve the citric acid powder in water. Since citric acid has a high dissolution rate, scale removal can be performed in the same way as when using a citric acid solution.

If it is not necessary to remove the scale in the flow path from the electrolytic cell 2 to the pH sensor 7 and only the cleaning of the pH sensor 7 is sufficient, the tip of the discharge pipe 18 should be positioned farther than the pH sensor 7. The citric acid solution may be poured from the discharge pipe 18 at a high position.

Further, a separate cleaning cartridge is prepared in the cartridge containing the filter media 31 and 32 in the water purifier 3, and the cleaning cartridge is filled with the citric acid powder, for example 50, in the filling portion of the filter media 31 which is activated carbon. ~
About 100 g is sealed, and when cleaning the pH sensor 7, the cartridge of the water purifier 3 is replaced with this cleaning cartridge, the discharge pipe 17 is plugged, and one of the switches SW ₁₂ and SW ₁₃ is pressed to close it. At any time, the electromagnetic valve 63 of the type capable of supplying water from the water purifier 3 side to the electrolytic cell 2 side may be closed to allow water to flow for a while, and then left for a predetermined time. In this case, it is not necessary to switch the switching valve 6 to the state shown in FIG.

When using the cartridge of the water purifier 3,
Not only can the amount of citric acid used be increased, but since citric acid can be added to all the water sent to the electrolyzer 2, it is effective when using groundwater that contains a large amount of calcium or carbonate. Is. Although citric acid was used for cleaning here, any organic acid certified as a food additive such as malic acid, fumaric acid, oxalic acid, formic acid, and maleic acid may be used to dissolve the scale.

[0065]

As described above, according to the present invention, in the control of gradually lowering the electrolysis voltage for the detection of the current exceeding the preset upper limit value of the current supplied to the electrolytic cell, the voltage drop with respect to the power supply is reduced. The output interval of the instruction is adjusted to the voltage drop rate of the power supply section, and the voltage drop instruction to the power supply section is output according to the response speed of the power supply section, so that the electrolytic voltage drop depends on the detected pH value. Therefore, overshoot due to the response speed of the power supply does not occur during overcurrent detection, and the target pH
In addition to enabling smooth control toward the value, the maximum electrolysis voltage can be applied within the set upper limit current value.

[Brief description of drawings]

FIG. 1 is a block circuit diagram of an embodiment.

[Fig. 2] Fig. 2 is a schematic diagram showing the same as above when ejecting alkaline ionized water or weakly acidic ionized water.

[Fig. 3] Fig. 3 is a schematic diagram showing the same acid ionized water as above being discharged.

FIG. 4 is a cross-sectional view of the above backwash unit and a switching valve.

5A and 5B show the pH sensor of the above, wherein FIG. 5A is a schematic sectional view and FIG. 5B is an output characteristic diagram.

FIG. 6 is a front view of the operation display unit of the above.

[Fig. 7] Fig. 7 is an operation explanatory diagram showing an algorithm of feedback control in the same as above.

FIG. 8 is a voltage-pH characteristic diagram in the feedback control of the above.

9A is a voltage-pH characteristic diagram in a comparative example, and FIG. 9B is a voltage-pH characteristic diagram in the present invention.

FIG. 10 is a diagram for explaining the operation of the dead zone process of the above.

FIG. 11 is an operation explanatory diagram for determining groundwater according to the above.

FIG. 12 is a flowchart showing an operation of the above.

FIG. 13 is a schematic view of a conventional example.

[Explanation of symbols]

C control circuit DV power supply 2 electrolysis tank 7 pH sensor

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Toshikazu Nishikawa             1048, Kadoma, Kadoma-shi, Osaka Matsushita Electric Works Co., Ltd.             Inside the company (72) Inventor Toshihisa Hirai             1048, Kadoma, Kadoma-shi, Osaka Matsushita Electric Works Co., Ltd.             Inside the company (72) Genki Nakano             1048, Kadoma, Kadoma-shi, Osaka Matsushita Electric Works Co., Ltd.             Inside the company F-term (reference) 4D061 DA03 DB07 DB08 EA02 EB12                       EB19 EB37 EB38 EB39 EB40                       ED12 FA06 FA09 GA22 GA30                       GB20 GC11 GC14 GC18 GC20

Claims (2)

[Claims] 1. When generating alkaline ionized water and acidic ionized water by electrolysis in an electrolyzer and discharging the electrolyzed water separately, the electrolyzer is operated in accordance with the pH value of the electrolyzed water measured by a pH sensor. In the method for producing electrolyzed water that controls the electrolysis voltage to be applied, the electrolysis voltage is gradually lowered in response to detection of a current exceeding the preset upper limit current value for the current to be supplied to the electrolysis cell. The method for producing electrolyzed water is characterized in that the output interval of the voltage drop instruction to the is adjusted to the voltage drop rate of the power supply section. 2. An electrolyzed water generator for producing alkaline ionized water and acidic ionized water by electrolysis in an electrolyzer and discharging the electrolyzed water separately, and a pH sensor for measuring the pH value of the electrolyzed water. And a control circuit for controlling the electrolysis voltage applied to the electrolyzer according to the pH value measurement result of the electrolyzed water by the pH sensor, and detecting the current exceeding the preset upper limit current value for the energizing current to the electrolyzer The control circuit for performing a control to gradually lower the electrolytic voltage with respect to
An electrolyzed water generation apparatus characterized in that, when gradually lowering the electrolysis voltage, the output interval of the voltage drop instruction to the power supply unit is adjusted to the voltage drop speed of the power supply unit.