JP2991016B2 - Continuous ion-rich water generation method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[Object of the invention]

BACKGROUND OF THE INVENTION The present invention relates generally to a technique for reforming tap water by electrolysis to adjust the hydrogen ion concentration (pH) of the tap water. More specifically, the present invention relates to a method and apparatus for continuously producing hydrogen ion-rich acidic water and / or hydroxyl ion-rich alkaline water by electrolysis of tap water. The present invention particularly relates to a method and an apparatus capable of obtaining ion-rich water having a desired arbitrary pH value regardless of the quality of tap water.

[0002]

2. Description of the Related Art Alkaline water rich in hydroxyl ions (OH ⁻ ) is conventionally called “alkali ion water”,
It is considered that it has an effect of promoting health when served in a beverage, and has an effect of enhancing the taste when used in tea, coffee and the like or in cooking. In addition, hydrogen ions (H ⁺ )
Rich acidic water is known to be suitable for boiling and washing face of noodles. Attention has been paid.

[0003] For this reason, various types of ion-rich water generators (often referred to in the industry as ion water generators) are commercially available or proposed. The ion-rich water generator utilizes the electrolysis of water.At the interface between the anode and water, OH ⁻ present in the water due to ionization of the water gives electrons to the anode and is oxidized to oxygen gas. Removed from the system. As a result, the H ⁺ concentration increases at the interface between the anode and water, and H ⁺ -rich acidic water is generated. On the other hand, at the interface between the cathode and water, H ⁺ is reduced to hydrogen by receiving electrons from the cathode plate, because they are removed by a hydrogen gas, OH ^- concentration is increased, the cathode side O
H ^- rich alkaline water is produced.

[0004] Early ion-rich water generators were of the batch treatment type, but today, the continuous treatment type of electrolyzing the water while passing the water through an electrolytic cell is generally used. The continuous ion-rich water generator has a membrane with an ion-permeable and water-impermeable membrane for preventing acidic water generated on the anode side by electrolysis and alkaline water generated on the cathode side from mixing. Type of device (for example,
No. 0292, JP-A-58-189090, JP-B-58-47985),
Non-diaphragm type ion-rich water generation that separates acidic water and alkaline water without using a diaphragm by flowing water in a laminar flow through a water passage between a pair of opposed electrode plates. Apparatus (for example, Japanese Utility Model Publication No. 57-8957, JP-A-4-284
No. 889, Japanese Utility Model Application No. 4-110189, and Japanese Patent Application No. 5-59498).

[0005] When producing ion-rich water, it is desirable to obtain ion-rich water (acidic water or alkaline water) having a desired pH value according to the application. By the way, as described above, since the generation of ion-rich water is based on the electrolysis of water, in a continuous ion-rich water generator, the pH of the obtained ion-rich water is basically
It is determined by the strength of electrolysis and the flow rate of water flowing into the electrolytic cell. Therefore, in order to obtain ion-rich water having a desired pH value, first, the electrolysis intensity must be variably adjusted in accordance with the target pH value and the flow rate of water.

Further, it is known that the pH of the generated ion-rich water varies depending on the region. This is thought to be due to the fact that the quality of the raw water, particularly the content of bicarbonate ion (HCO ₃ ⁻ ), varies from region to region. Graph of Figure 1 (horizontal axis is logarithmic scale)
When the raw water is pure water, as shown by a straight line A, the pH of the produced water is linear according to the amount of H ⁺ (or OH ⁻ ) generated by electrolysis. Changes to However, carbon dioxide in the atmosphere is actually dissolved in tap water such as tap water, and the dissolved carbon dioxide is converted into bicarbonate ion (HCO ₃ ⁻ ) and carbonate ion (CO 2) depending on the pH of the tap water. ₃ ^2- ) and the following equilibrium state.

[0007] ^{_{CO 2 ⇔ HCO 3 - ⇔ CO}} 3 2- equilibrium transitions depending on the pH as shown in the graph of FIG. 2, the abundance ratio of these carbonates will vary depending on the pH. That is, at pH 8.3, all carbonate groups are present in the form of bicarbonate ions, but when the pH becomes more alkaline, the bicarbonate ions release hydrogen ions as shown in the following formula, and carbonate ions are generated.

HCO ₃ ⁻ → CO ₃ ²⁻ + H ⁺ (1) Conversely, when the pH is on the acidic side, carbon dioxide and water are generated while consuming hydrogen ions in tap water as in the following formula.

H ⁺ + HCO ₃ ⁻ → CO ₂ + H ₂ O (2) Accordingly, bicarbonate ions (HCO ₃ ⁻ ) dissolved in tap water act as buffer components in the electrolysis of water, The relationship between the amount of H ⁺ (or OH ⁻ ) generated by the above and the actually obtained pH is as shown by a curve B in the graph of FIG. That is, when the acidic water is to be produced, as indicated by the hatched area C, the H ⁺ generated by the electrolysis is consumed by the reaction of the formula (2), so that compared to the case of electrolyzing the pure water. Unless the amount of electrolysis is increased, H ⁺ cannot be increased. When alkaline water is to be obtained, as indicated by the hatched area D, bicarbonate ions generate H ⁺ by the reaction of the formula (1).
H ⁺ cannot be reduced unless electrolysis is enhanced and the amount of generated OH ⁻ is increased as compared with pure water.

Therefore, in order to obtain ion-rich water having a desired pH value, it is necessary to adjust the electrolytic strength according to the quality of the raw water, more specifically, the amount of dissolved bicarbonate ions.

[0011]

In the prior art,
It has been proposed that the pH value of the ion-rich water flowing out of the electrolytic cell is detected by a pH sensor, and the voltage applied to the electrolytic cell or the electrolytic power is feedback-controlled so that the pH of the ion-rich water becomes a desired value. (For example,
5-22093, JP-A-5-64785). According to this method, since the electrolytic power is feedback-controlled according to the pH value of the ion-rich water, ion-rich water having a desired pH value can be obtained regardless of the quality of the raw water.

However, a problem with this method is that a pH sensor that can be used for feedback control of the pH of ion-rich water has not been realized with today's pH measurement technology. For example, a pH sensor based on the ion electrode method generates considerable noise due to the influence of the electric field of the electrolytic cell of the ion-rich water generator, and thus cannot detect pH with a precision required for practical use. Also, other types of pH sensors have poor responsiveness and are not suitable for feedback control.

An object of the present invention is to provide a continuous ion-rich water producing method and apparatus capable of obtaining ion-rich water having a desired arbitrary pH regardless of fluctuations in water quality without using a pH sensor. That is.

[0014]

Configuration of the Invention

SUMMARY OF THE INVENTION The present inventor has found that there is a close correlation between the bicarbonate ions dissolved in tap water and the electrical conductivity of tap water. The present invention is based on such knowledge, and the method and apparatus for generating ion-rich water of the present invention first determine the electric conductivity of tap water, and determine the required electrolytic power based on the determined electric conductivity. By supplying the determined electrolytic power to the electrolytic cell, ion-rich water is generated by electrolysis of tap water. Since there is a correlation between the electric conductivity of tap water and bicarbonate ions, by determining the required electrolysis power based on the measured electric conductivity, the electrolysis power can be adjusted to the bicarbonate ions dissolved in the tap water. The value takes into account the amount of That is, when the electric conductivity of tap water is high, it is considered that the amount of bicarbonate ions is large, and the electrolytic power is increased accordingly.

In this way, the electric conductivity of tap water is determined,
Since the required electrolysis power is determined based on the electric conductivity, ion-rich water having a desired pH can be obtained without using a pH sensor. The determination of the electric conductivity of tap water can be performed by measuring an electrolytic voltage and an electrolytic current applied to the electrolytic cell, and calculating the electric conductivity based on the measured voltage and current. When the electric conductivity is calculated based on the voltage and the current as described above, the control circuit can be configured very simply and at low cost. The electrolytic power supplied to the electrolytic cell can be increased or decreased according to the target pH value and the flow rate of the ion-rich water.

The continuous ion-rich water generating apparatus according to the present invention comprises: an electrolytic cell; means for setting a target pH value of the ion-rich water; voltage detecting means for detecting an electrolytic voltage applied to the electrolytic cell; Current detecting means for detecting the electrolytic current applied to the electric field, electric conductivity calculating means for calculating the electric conductivity of tap water based on the voltage and current detected by the detecting means, and a target set by the setting means. power calculating means for calculating the theoretical required electrolytic power according to the pH value and the electrical conductivity calculated by the electrical conductivity calculating means, power supply means for supplying electrolytic power to the electrolytic cell, and electric power supplied to the electrolytic cell. Control means for controlling the power supply means such that the electric power becomes the theoretical electrolysis power. Preferably, the apparatus further comprises a flow rate detecting means for detecting a flow rate of clean water flowing through the electrolytic cell, and the electric power calculating means has a target pH value set by the setting means and the electric conductivity calculated by the electric conductivity calculating means. The theoretical electrolysis power is calculated based on the degree and the flow rate detected by the flow rate detection means.

The above features and effects of the present invention, as well as other features and advantages, will be described in more detail with reference to the following embodiments.

[0018]

First, an example of an electrolytic cell that can be used in the present invention will be described with reference to FIGS. The electrolytic cell 12 of the illustrated ion-rich water generator 10 is a non-diaphragm type,
In the recess of the resin pressure-resistant case 14, three electrode plates of a first anode plate 16, a cathode plate 18 and a second anode plate 20 are sequentially arranged while sandwiching a plurality of resin spacers 22.
By screwing it to the case 14 in a liquid-tight manner. Terminals 16 are provided on the electrode plates 16, 18 and 20.
A, 18A, and 20A are respectively fixed, and are connected to a DC power supply described later.

As can be clearly seen from FIG. 4, the case 14 has a water inlet 26, an alkaline water outlet 28, and an acidic water outlet 30 formed therein. The water inlet 26 is connected to the water distribution passage 32
As shown in FIG. 5, the water distribution passage 32 is formed by the case 14 and the cover 24, and extends over the entire length of the electrode plate in the vertical direction.

As can be clearly seen from the enlarged sectional view of FIG.
A first water passage 34 is provided between the first anode plate 16 and the cathode plate 18.
Is formed, and a second water passage 36 is formed between the cathode plate 18 and the second anode plate 20. These water passages 34 and 36 cooperate with the electrode plates 16, 18 and 20 to act as an electrolytic chamber. Each of the water passages 34 and 36 is divided into four upper and lower sub-water passages by the spacer 22 extending in the horizontal direction. As can be seen from FIG.
Since the upstream ends of 4 and 36 communicate with the water distribution passage 32, the water flowing down from the water inlet 26 along the distribution passage 32 is supplied to the four sub-water passages of the respective water passages 34 and 36. And flows in the horizontal direction as shown in FIG. Since the distance between the electrodes is sufficiently small, the capacity of the distribution passage 32 is large, so that the water flow flowing in the water passages 34 and 36 in the horizontal direction becomes laminar, and the acidic water generated on the surface of the anode plate and the water flow generated on the surface of the cathode plate. The alkaline water can be separately recovered without using a diaphragm.

As shown in FIGS. 5 and 8, the downstream ends of the water passages 34 and 36 serving as the electrolytic chambers are open to an alkaline water recovery passage 38 formed by the case 14 and the cover 24. . The alkaline water recovery passage 38 communicates with the alkaline water outlet 28, and extends over the entire length of the electrode plate in the vertical direction, similarly to the clean water distribution passage 32.

As can be clearly understood from FIG. 5, the case 14 and the cover 24 are further formed with grooves 40 and 42 extending over the entire length of the anode plates 16 and 20 in the vertical direction, respectively, and cooperate with the anode plates. And acid water recovery passage 4
4 and 46 are formed. The lower ends of these acidic water recovery passages 44 and 46 join at a communication port 48 (FIGS. 6 and 7), and further communicate with the acidic water outlet 30 (FIG. 4).

As can be clearly seen from FIGS. 3 and 8, anode plates 16 and 20 have their downstream edges 16B
And slits 16C and 20C acting as acid water recovery ports are formed on the upstream side of the slits 16C and 20B, respectively. The acid water passing through the slits 16C and 20C flows into the acid water recovery passages 44 and 46. I have. The acidic water flowing out of the slits 16C and 20C is collected in the acidic water collecting passages 44 and 46, and is further sent to the acidic water outlet 30 therefrom.

When using the ion-rich water generator 10, the water inlet 26 can be connected to a faucet of a water pipe by a hose or the like. The temperature and flow rate of the tap water are detected by a temperature sensor 50 composed of a thermistor and a flow sensor 52 composed of an impeller and a pulse generator, respectively. Flow control valves 54 and 56 can be connected to the alkaline water outlet 28 and the acidic water outlet 30 of the electrolytic cell 12, respectively. When the acidic water obtained at the acidic water outlet 30 is used, the ratio of the flow rate of the alkaline water obtained at the alkaline water outlet 28 to the flow rate of the acidic water obtained at the acidic water outlet 30 is about 4: 1. When the alkaline water obtained at the alkaline water outlet 28 is used, the flow control valve is controlled so that the flow ratio between the alkaline water outlet 28 and the acidic water outlet 30 is, for example, about 3: 2. Can be controlled.

FIG. 9 shows an embodiment of the power control circuit of the ion-rich water generator 10. In the illustrated embodiment, the control circuit 60 includes a switching power supply circuit 62 and a programmed microcomputer (hereinafter, microcomputer) 64 for controlling the power supply circuit. Schematically, the control circuit 60 allows the microcomputer 64 to theoretically calculate the required electrolysis power of the electrolytic cell 12 based on various parameters, so that the power actually supplied to the electrolytic cell becomes the required electrolytic power. The microcomputer 64 is configured to feedback-control the switching power supply circuit 62. More specifically, the switching power supply circuit 62 includes a photocoupler 66, a capacitor 68 for smoothing the output thereof, a switching power supply IC 70 having a pulse width modulation function, a switching transistor 72, and a switching transformer 74.
Having. The current from the commercial AC power supply 76 is a diode
Full-wave rectified by a bridge 78, the DC output of which is applied to the primary side of a switching transformer 74. The pulse width of the DC current flowing through the primary coil of the switching transformer 74 is controlled by the switching transistor 72 driven by the switching power supply IC 70, and the power corresponding to the duty ratio of the primary side pulse is used as the secondary power of the switching transformer 74. Induced in the coil. The secondary coil of the switching transformer 74 is connected to the anode plate and the cathode plate of the electrolytic cell 12 via a changeover switch 80 for inverting the polarity of the voltage. The changeover switch 80 is interlocked with a relay 81 driven by the microcomputer 64, and removes deposits such as calcium carbonate adhered to the electrode plate by periodically switching the polarity of the voltage applied to the electrolytic cell. belongs to.

Electrolysis cell 12 and switching transformer 74
And a current detecting resistor 82 for detecting a current flowing in the electrolytic cell is connected in series to
A pair of voltage detecting resistors 84 for detecting a voltage applied to the electrolytic cell are connected in parallel. The connection between these resistors 82 and 84 is connected to the A / D conversion input terminal of the microcomputer, and the microcomputer 64 detects the current and voltage supplied to the electrolytic cell by periodically checking the potential of the connection. I do.

The control circuit 60 further includes a pH for enabling a user to set a target pH for the ion-rich water.
A setting switch 86 is provided, the output of which is input to the input terminal of the microcomputer. The microcomputer 64, for example, supplies acidic water of pH 6.5 in the acidic water discharge mode and pH 8.5, pH 9.0, or pH in the alkaline water discharge mode.
9.5 alkaline water can be programmed to be selected, and the pH set value can be sequentially switched each time the pH set switch 86 is pressed.
The microcomputer detects the target pH set by the user by periodically checking the pH setting switch 86. The set target pH value is displayed to the user by turning on one of the LEDs 88.

Further, the output of the thermistor 50 as a water temperature sensor is input to the A / D conversion input terminal of the microcomputer 64, and the output pulse of the flow sensor 52 is input to the microcomputer 64 via the input circuit 90.

Next, the operation of the microcomputer 64 will be described with reference to the flowchart of FIG. When the power is turned on to the ion-rich water generator 10 by connecting the power outlet, the microcomputer is initialized (S10).
1). When the initialization is completed, an appropriate initial value is set as the required power (S102). This is because the required power value is learned as described later, but there is no learned value immediately after the power is turned on. Next, the output of the flow sensor 52 is input (S103), and the flow rate of water flowing into the electrolytic cell 12 is calculated (S104). Next, the pH setting switch 86 is checked (S105), and the target pH value set by the user is displayed on the LED 88 (S106). Next, it is determined whether or not the flow rate is zero (S107). If the flow rate is zero, the output of the power value to the photocoupler 66 is stopped (S108).
The learning flag indicating whether or not the required power value has been learned is reset to zero (S109).

When the use of the apparatus is detected by detecting the flow rate in the flow rate determination (S107), it is determined whether the required power value has already been learned (S110). If not completed, the required power initial value set in S102 is read (S111), and a signal having a pulse width corresponding to the initial value is output from the power control terminal to the photocoupler 66 (S112). Thereby, power supply to the anode plate and the cathode plate of the electrolytic cell 12 is started, and electrolysis of tap water is started. The current I flowing between the electrode plates of the electrolytic cell and the voltage V applied between the electrode plates are detected by detecting the potential at the connection between the current detecting resistor 82 and the voltage detecting resistor 84.
Is detected (S113-114), and the electric conductivity κ of tap water is calculated (S115).

The calculation of the electric conductivity κ can be performed as follows based on the detected current I and voltage V. First, the conductivity coefficient of tap water is calculated. The conductivity coefficient χ is expressed by the following equation.

Χ = S · d / A (3) (where S is the conductance of water, d is the electrode interval, and A is the electrode area) S = I / (V−V ₀ ) (V ₀ is the hydrogen overvoltage) ) Into equation (3), χ = I · d / {(V−V ₀ ) A} (4) Equation (4) can be rewritten as follows.

Χ = K · I / (V−V ₀ ) (5) (where K is a constant) The water conductivity coefficient χ substantially corresponds to the electric conductivity κ (χ
= Κ), κ = KI / (V-V ₀ ) (6) The electric conductivity κ obtained in this manner is stored in the memory of the microcomputer 64 as a learning value (S116). Next, pH
The set value and the flow rate Q are read (S117), and the required electrolysis power required to obtain ion-rich water having a desired pH is calculated (S118). The calculation of the required power W can be performed by the following equation.

W = K ₁ + K ₂ · Q + K ₃ · κ + K ₄ (pH-7) ² (7) (where K ₁ , K ₂ , K ₃ and K ₄ are constants) When the electric conductivity and the bicarbonate ion concentration of the water in each place were measured, the result shown in FIG. 11 was obtained. This shows that there is a close correlation between the electrical conductivity of water and the concentration of dissolved bicarbonate ions. Therefore, the electric conductivity κ obtained by the equation (6) is used as an expression of the amount of bicarbonate ions, the required electrolysis power W is theoretically calculated by the equation (7), and this power is supplied to the electrolytic cell. Thus, ion-rich water having a pH value set by the user can be obtained.

The theoretically required electrolysis power W calculated in this way is stored in a memory as a learning value (S119).
The learning flag is set to "1" (S120), and the learning value is set to PI
Photo-coupler 66 by D control (proportional-integral-derivative control)
(S121). Thus, the switching power supply circuit 62 is feedback-controlled so that the power actually supplied to the electrolytic cell becomes the required electrolytic power W.

As described above, in the above-described embodiment, the electrolytic power according to the electric conductivity of water, the target pH value set by the user, and the flow rate is supplied to the electrolytic cell. Ion-rich water having a desired pH value is obtained irrespective of fluctuations in flow rate and flow rate.

[0037]

As described above, according to the present invention,
Electrolytic power is supplied to the electrolytic cell in consideration of the amount of bicarbonate ions based on the electric conductivity of tap water, so that ion-rich water having a desired pH value can be used in any region without using a pH sensor. Can be obtained.

When calculating the electric conductivity by detecting the voltage and current applied to the electrolytic cell, the circuit configuration can be made extremely simple and inexpensive.

Further, when the electrolytic power is determined in consideration of the flow rate, ion-rich water having a desired pH value can be obtained irrespective of the fluctuation of the flow rate.

[Brief description of the drawings]

FIG. 1 is a graph showing the relationship between the amount of hydrogen ions generated by electrolysis of water and pH, and the horizontal axis is a logarithmic scale.

FIG. 2 is a graph showing a change in pH and an abundance ratio of various carbonate groups.

FIG. 3 is an exploded perspective view of an electrolytic cell of the non-diaphragm type continuous ion-rich water generator of the present invention.

FIG. 4 is a partially cutaway rear view of the electrolytic cell shown in FIG. 3;

FIG. 5 is a cross-sectional view taken along line VV of FIG. 4;
The electrode plate and the spacer are omitted for simplification of the drawing.

FIG. 6 is a sectional view taken along the line VI-VI in FIG. 4;

FIG. 7 is a sectional view taken along the line VII-VII in FIG. 4;

FIG. 8 is an enlarged view of a portion inside a circle A in FIG. 5;

FIG. 9 shows a power control circuit of the device of the present invention.

FIG. 10 is a flowchart showing the operation of the microcomputer.

FIG. 11 is a graph showing a relationship between electric conductivity and bicarbonate ion concentration.

[Explanation of symbols]

 10: Continuous ion-rich water generator 12: Electrolyzer 16, 18, 20: Electrode plate 62/64: Power control means 64: Electric conductivity calculation means, power calculation means 76/78: Power supply means 82/64: Current detecting means 84/64: Voltage detecting means 86/64: pH setting means

Continuation of the front page (72) Inventor Shigeru Ando 2-1-1 Nakajima, Kokurakita-ku, Kitakyushu-shi, Fukuoka Prefecture Totoki Co., Ltd. (56) References JP-A-6-71264 (JP, A) JP-A-Hei 6-134463 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) C02F 1/46-1/48

Claims (7)

(57) [Claims] When the water is electrolyzed while passing the water through an electrolytic cell to produce hydrogen ion-rich acidic water and / or hydroxyl ion-rich alkaline water, the water conductivity is reduced. Determining the amount of bicarbonate ions dissolved in tap water based on the determined electrical conductivity, and increasing the electrolytic power in accordance with the increase in the electrical conductivity.
A method for producing continuous ion-rich water, comprising determining required electrolysis power to reduce electrolysis power in accordance with a decrease in conductivity, and supplying the determined electrolysis power to an electrolytic cell. 2. The electric conductivity of tap water is determined by measuring an electrolytic voltage and an electrolytic current applied to an electrolytic cell and calculating the electric conductivity based on the measured voltage and current. The method for producing ion-rich water according to claim 1, wherein: 3. The method for producing ion-rich water according to claim 1, wherein the electrolytic power supplied to the electrolytic cell is adjusted according to a target pH value of the ion-rich water. 4. The method for producing ion-rich water according to claim 1, wherein the electrolytic power supplied to the electrolytic cell increases in accordance with the flow rate of tap water flowing through the electrolytic cell. 5. The method according to claim 1, wherein when the clean water is electrolyzed while passing the clean water through the electrolytic cell, hydrogen ion-rich acidic water and / or hydroxyl ion-rich alkaline water are generated. A method for producing continuous ion-rich water, characterized by determining the amount of an electrolysis buffer component dissolved in tap water by detection, and increasing electrolysis power supplied to an electrolysis tank according to the amount of the electrolysis buffer component. 6. Continuous ion-rich water which is capable of producing hydrogen ion-rich acidic water and / or hydroxyl ion-rich alkaline water by electrolyzing the water while passing the water through an electrolytic cell. In the generator, a means for setting a target pH value of ion-rich water, a voltage detecting means for detecting an electrolytic voltage applied to the electrolytic cell, a current detecting means for detecting an electrolytic current applied to the electrolytic cell, Electric conductivity calculating means for calculating the electric conductivity of tap water based on the voltage and current detected by the detecting means; and a target pH value set by the setting means and calculated by the electric conductivity calculating means. Electrical conductivity based on electrical conductivity
As the conductivity increases, the electrolytic power increases and the electrical conductivity decreases.
Power calculating means for calculating the theoretical required electrolysis power to reduce the electrolysis power according to the following, power supply means for supplying the electrolysis power to the electrolyzer, and power supplied to the electrolyzer being the theoretical electrolysis power Control means for controlling the power supply means so as to provide a continuous ion-rich water generating apparatus. 7. A flow rate detecting means for detecting a flow rate of tap water flowing through the electrolytic cell, wherein the electric power calculating means calculates a target pH value set by the setting means and an electric power calculated by the electric conductivity calculating means. The ion-rich water generator according to claim 6, wherein the theoretical electrolysis power is calculated based on the conductivity and the flow rate detected by the flow rate detection means.