JP3055743B2 - Non-diaphragm type electrolytic cell for ion-rich water generation - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[Object of the invention]

BACKGROUND OF THE INVENTION The present invention relates generally to an apparatus for reforming tap water by electrolysis and adjusting the hydrogen ion concentration (pH) of the tap water. More specifically, the present invention relates to an electrolytic cell that produces hydrogen ion-rich acidic water and / or hydroxyl ion-rich alkaline water by electrolysis of tap water. The present invention particularly relates to an improvement in a non-diaphragm type electrolytic cell.

[0002]

2. Description of the Related Art Alkaline water rich in hydroxyl ions (OH ⁻ ) is conventionally called “alkali ion water”,
It is considered that when used for drinking, it has an effect on promoting health, and when used for tea, coffee, etc., or for cooking, it has an effect of enhancing the taste. In addition, hydrogen ions (H ⁺ )
Rich acidic water is known as being suitable for boiling noodles, and strong acidic water with a high hydrogen ion concentration is attracting attention as being useful for sterilization and sterilization of kitchen cutting boards and cloths. I have.

[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 and has an electrolytic cell provided with an anode and a cathode. When a DC voltage is applied between the anode and the cathode, as schematically shown in FIG. 1, at the interface between the anode and the water, OH ⁻ present in the water due to ionization of the water gives electrons to the anode. Oxidized,
It becomes oxygen gas and is 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 ⁺ receives electrons from the cathode plate and is reduced to hydrogen and is removed as hydrogen gas, so that the OH ⁻ concentration increases, and the OH ⁻ rich alkaline Water is produced.

[0004] In the early days, the electrolytic cell for producing ion-rich water was of a batch processing type, but today, a continuous flow type electrolytic cell is generally used, the latter being formed between an anode and a cathode. While passing through the water passage, the water is electrolyzed to generate ion-rich water. Continuous electrolytic cells can be broadly classified into two types: a diaphragm type and a non-diaphragm type.

In a diaphragm type electrolytic cell, as disclosed in, for example, Japanese Utility Model Application Laid-Open No. 56-80292, Japanese Patent Application Laid-Open No. 58-189090, and Japanese Utility Model Application No. The water passage formed and acting as an electrolytic chamber is separated by an ion-permeable and water-impermeable diaphragm, so that acidic water generated on the anode side by electrolysis and alkaline water generated on the cathode side do not mix. ing. As described above, the presence of the water-impermeable membrane prevents the mixing of the acidic water and the alkaline water, so that the membrane-type electrolytic cell can easily and easily generate the generated acidic water and the alkaline water at desired arbitrary flow rates. There is an advantage that it can be taken out.

However, the drawback of the diaphragm type electrolytic cell is that
(1) Bacteria and microorganisms can easily grow at the diaphragm.
It is not hygienic, and (2) the power consumption of the device increases because the electrode interval must be increased in order to arrange the diaphragm.

Therefore, in the prior art, there has been proposed a so-called "diaphragm-type" electrolytic cell in which the diaphragm between the anode and the cathode is abolished (for example, Japanese Utility Model Publication No. 57-8957, Japanese Unexamined Patent Publication No. 4-284).
No. 889, No. 4-110189). A non-diaphragm type electrolytic cell utilizes the principle of laminar flow, in which an anode plate and a cathode plate are juxtaposed and juxtaposed to each other without an intervening diaphragm, and along the anode plate and the cathode plate. The water is passed while forming a laminar flow to electrolyze the water. Such a non-diaphragm type electrolytic cell has an advantage that it is sanitary because there is no diaphragm, and power consumption can be reduced because the interval between electrodes can be reduced.

[0008]

However, the problem of the non-diaphragm type electrolytic cell is that the diaphragm for separating the acidic water and the alkaline water is eliminated, so that the desired concentration at the outlet of the water passage acting as the electrolysis chamber is required. It is very difficult to separate the acidic and alkaline water separately.

For example, in the apparatus of Japanese Utility Model Publication No. 57-8957, acidic water generated along the anode plate and alkaline water generated along the cathode plate are separated by a wedge-shaped separation plate, and each outlet is separated. Is to be collected from
In this structure, since the position of the separation plate is fixed,
Only strong alkaline water or strong acid water cannot be taken out.

[0010] Also, Japanese Patent Application Laid-Open No. 4-248889 and Japanese Utility Model Application Laid-Open No.
In the apparatus of No. 0189, a baffle plate is provided facing the end of the water passage, the alkaline water flows to an alkaline water outlet disposed at an extension of the water passage, and the acidic water collides with the baffle plate and turns back. It is designed to be discharged from the exit. In this structure, turbulence is generated by collision with the baffle plate, and the alkaline water and the acidic water are inevitably mixed. Therefore, similarly, it is possible to selectively recover only the strong alkaline water or the strong acidic water. There is a drawback that you can not.

That is, FIG. 2 (the numerical values in the figure represent pH values,
(The electrode spacing is exaggerated to show layers of different concentrations for clarity.) In a non-diaphragm type electrolytic cell, water is applied while applying a voltage between the anode plate and the cathode plate. Then, water flows along the electrode plate while forming a laminar flow in which the hydrogen ion concentration gradually changes from a strong acidity to a strong alkalinity.
When it is narrowed to less than mm, the layer of strong alkaline water and the layer of strong acid water become very thin, respectively, so even if only a very small turbulence occurs, the acidic water and the alkaline water are easily mixed. Will.

An object of the present invention is to make it possible to recover strongly alkaline and / or strongly acidic ion-rich water by improving the outlet of a water passage (electrolysis chamber) of a diaphragmless electrolytic cell. is there.

[0013]

Configuration of the Invention

To achieve the above object, the present invention is based on the following findings. First, in order to selectively recover only strongly alkaline water or strongly acidic water in a non-diaphragm type electrolytic cell, a laminar flow whose hydrogen ion concentration gradually changes from strongly acidic to strongly alkaline as shown in FIG. A strong alkaline water and / or a strongly acidic water must be taken out while being formed in the water passage (electrolysis chamber) and maintaining the laminar flow without disturbing. Therefore, in the present invention, the water passage (electrolysis chamber) is defined by two flat wall surfaces extending over the entire length of the water passage direction, and the downstream end of the water passage is cut off by a flow passage larger than its flow passage cross-sectional area. An opening is made directly into the first ion-rich water recovery passage having an area, and alkaline water (or acidic water) is recovered from the first ion-rich water recovery passage. A recovery port for acidic water (or alkaline water) is opened at one of these two wall surfaces upstream of the downstream end of the water passage to maintain laminar flow in the water passage. , A thin layer of strongly acidic water (or strongly alkaline water) is separated from it, and the strongly acidic water (or strongly alkaline water) is recovered from this recovery port.

According to the present invention, it is further found that the length R of the recovery port in the water flow direction is closely related to the state of the flow of the acidic water (or the alkaline water) branching into the recovery port from the water passage. It is based on According to the present invention, in order to recover strongly acidic water (or strongly alkaline water) without generating turbulence in the flow of acidic water (or alkaline water) flowing into the recovery port, the length of the recovery port in the water flow direction is set. It is noted that R must be optimized.
According to the knowledge of the present inventor, the length R of the recovery port in the water flow direction is determined.
When the width d (electrode interval) of the water passage is three times or less, turbulence can be prevented from occurring in the flow of acidic water (or alkaline water) flowing into the recovery port.

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.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, referring to FIGS.
The overall configuration and operation of the diaphragmless electrolytic cell of the present invention will be described.

Referring mainly to FIGS. 3 and 4, the diaphragmless electrolytic cell 10 has a vertically long housing 12. In the housing 12, three electrode plates of a first anode plate 16, a cathode plate 18, and a second anode plate 20 are sequentially arranged in a recess of a resin pressure-resistant case 14 with a plurality of resin spacers 22 interposed therebetween. , The cover 24 is screwed to the case 14 in a liquid-tight manner. By arranging the anode plates 16 and 20 on both sides of the cathode plate 18, respectively, the electrolytic cell 10 has a so-called double cell structure. By effectively utilizing both surfaces of the cathode plate 18, the processing capacity is doubled. It can be stored in a small space. In the illustrated embodiment, the voltage is applied such that the electrode plates 16 and 20 act as anode plates and the electrode plate 18 acts as a cathode plate, but it is of course possible to reverse the polarity of the applied voltage. .

The distance between the electrode plates is determined by, for example, five spacers 22. In this embodiment, the spacers 22 have a thickness of about 0.5 mm, so that the electrode spacing is about 0.5 mm. It has become. Preferably,
The electrode plates 16, 18, and 20 are manufactured by coating a titanium metal plate with platinum and each have a size of about 6 × 12 cm. Terminals 16A, 18 are provided on the electrode plates 16, 18, 20.
A and 20A are fixed respectively. These terminals 16A,
Both ends of 18A and 20A extend toward the front of the case 14, and can be connected to a DC power supply (not shown) of the electrolytic cell 10 only on the front side of the case. .

As can be clearly seen from FIG. 3, the case 14 has a clean water inlet 26 and ion-rich water outlets 28 and 30.
Is formed. In the embodiment shown, the electrode plates 16 and 2
0 acts as an anode plate and the electrode plate 18 acts as a cathode plate, so that the outlet 28 becomes an alkaline water outlet,
The outlet 30 is an acid water outlet. However, as described above, the polarity of the electrode plate can be reversed. In this case, the outlet 28 becomes an acidic water outlet, and the outlet 30 becomes an alkaline water outlet. The water inlet 26 communicates with a water distribution passage 32 having a substantially triangular cross section.
As can be clearly understood from FIG. 5, it is formed by the case 14 and the cover 24, and extends over the entire vertical length of the electrode plate. When using the electrolytic cell 10, the water inlet 26 can be connected to a water pipe by a hose or the like. Alternatively, the electrolytic cell 10 may be connected downstream of the water purifier, and the water purified by the water purifier may be introduced into the water inlet 26 of the electrolytic cell 10.

As can be clearly understood from the enlarged sectional views of FIGS. 8 and 9, the first anode plate 16 and the cathode plate 18
A water passage 34 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 function as an electrolytic chamber. In the embodiment shown, the water channels 34 and 36 are defined by the surfaces of the electrode plates 16, 18, 20 over their entire length.
Each of the water passages 34 and 36 is divided into four upper and lower sub-water passages by, for example, five spacers 22 extending in the horizontal direction. As can be seen from FIG.
Since the upstream ends of the and 36 communicate with the water distribution passage 32, the water flowing down from the water inlet 26 along the distribution passage 32 passes through the four sub-water passages of the water passages 34 and 36, respectively. It is distributed and flows horizontally into the water passages 34 and 36 as shown in FIGS. Since the capacity of the distribution passage 32 is large and the electrode interval is sufficiently small, 0.5 mm, the water flow flowing in the water passages 34 and 36 in the horizontal direction is laminar.

As shown in FIGS. 5 and 8, the downstream ends 34A of the water passages 34 and 36 acting as electrolysis chambers are provided.
And 36A are opened directly to an alkaline water recovery passage 38 having a substantially pentagonal cross section formed by the case 14 and the cover 24. The alkaline water recovery passage 38 communicates with the alkaline water outlet 28 and is connected to the clean water distribution passage 32.
Similarly, it extends over the entire vertical length of the electrode plate. As can be clearly understood from FIGS. 5 and 8, the cross-sectional area of the flow path of the alkaline water recovery passage 38 is made sufficiently large with respect to the cross-sectional areas of the flow paths of the water passages 34 and 36 so that the flow can be performed without generating turbulence. The alkaline water flows smoothly from the ends of the water channels 34 and 36 toward the alkaline water recovery passage 38.

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 the 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. 3).

As can be clearly seen from FIGS. 4 and 8, in the illustrated embodiment, the anode plates 16 and 20 have slits acting as acid water recovery ports upstream of their downstream edges 16B and 20B. 16C and 20C are formed respectively, and slits 16C and 20C are formed.
The water that has passed through C flows into the acidic water recovery passages 44 and 46. In the illustrated embodiment, the slits 16C and 20C acting as acid water recovery ports are formed in the anode plates 16 and 20, but the anode plates 16 and 20 are terminated at the slits 16C and 20C, and the slits 16C and 20C The downstream water passage wall surface may be formed by the case 14 and the cover 24 or another member.

As can be clearly understood from FIGS. 5 and 8, the cross-sectional area of the acidic water recovery passages 44 and 46 is also reduced by the slit 1.
6C and 20C are made sufficiently large with respect to the cross-sectional area of the flow passage, so that the acidic water recovered from the slit flows smoothly into the acidic water recovery passages 44 and 46 without generating turbulence. . Slits 16C and 20
The acidic water flowing out of C is collected in the acidic water recovery passages 44 and 46 over substantially the entire length of the anode plate in the vertical direction, and is further sent to the acidic water outlet 30 therefrom.

When using the electrolytic cell 10, the supply of clean water to the clean water inlet 26 can be controlled by a conventional manual or electric control valve (not shown), and the alkaline water outlet 28 and the acidic water Conventional flow control valves 50 and 52 can be connected to the water outlet 30, respectively. As described above, the clean water introduced from the clean water inlet 26 is uniformly distributed to the inlets (upstream ends) of the water passages 34 and 36 over the entire length of the electrode plates 16, 18, and 20 in the vertical direction by the distribution passage 32. Then, they flow into the water passages 34 and 36 in the horizontal direction.

When a DC voltage of, for example, about 12 V is applied between the cathode plate 18 and the anode plates 16 and 20, the electrolysis proceeds while water flows through the water passages 34 and 36, as shown in FIG. As described above, a flow in which the pH gradually changes in a direction perpendicular to the electric field between the anode plate and the cathode plate is generated.

When it is desired to obtain strong acidic water having a pH of about 3 suitable for sterilization at the acidic water outlet 30, the flow rate of the alkaline water obtained at the alkaline water outlet 28 and the flow rate of the acidic water obtained at the acidic water outlet 30 It is preferable to control the flow control valves 50 and / or 52 such that the ratio is about 4: 1. Under such a flow rate condition, when the thin layer of the strong acid water flowing slowly near the anode plate surface reaches the acidic water recovery slits 16C and 20C, it passes through the slits 16C and 20C as shown by arrows in FIG. Since it flows into the acidic water recovery passages 44 and 46, the acidic water outlet 3
At 0, strongly acidic water is obtained.

The pH at the alkaline water outlet 28 is
When it is desired to obtain about 10 strongly alkaline water, the flow rate ratio between the alkaline water outlet 28 and the acidic water outlet 30 is, for example, about 3:
2, the flow control valves 50 and / or 52 can be controlled.

Next, the relationship between the length of the acidic water collecting slits 16C and 20C in the water flow direction and the width of the water flow paths 34 and 36 will be described with reference to FIGS. Since the water passages 34 and 36 have a symmetric structure, only one of the water passages 36 is taken up. Referring to FIG. 10, the water passage 36 is defined by two flat wall surfaces 56 and 58 extending over the entire length in the water passage direction, and one wall surface 58 has a slit 20C opened. The water that has flowed into the water passage 36 flows in the water passage 36 while forming a laminar flow as shown by the flow velocity distribution curve 60. When the acid water layer reaches the recovery port 20C, it branches into the recovery port 20C, The remainder of the stream proceeds as it is and is recovered in the alkaline water recovery port passage 38.

As shown in FIG. 10, when the length R in the water flow direction of the acid water recovery port 20C is larger than the width d of the water passage 36, the flow direction of the acid water (the slit 20C
Is opened in the wall surface 58, so that the outflow direction is
When the laminar flow reaches the recovery port 20C, an excessive amount of flow tends to turn toward the acidic water recovery port 20C when the laminar flow reaches the recovery port 20C. As a result, large vortices 62 and 64 are generated in the acidic water recovery port 20C. With the generation of the vortex 62,
Since weakly acidic or alkaline water is involved in the strongly acidic water flowing into the acidic water recovery port 20C, strong acidic water cannot be obtained at the acidic water recovery port 20C. Also,
Due to the influence of the vortex 62, the flow velocity distribution of the flow toward the alkaline water recovery port passage 38 becomes as shown by a curve 66, and a part of the alkaline water is diluted with the acidic water. Further, a reverse flow is generated in the acidic water recovery port 20C due to the influence of the reverse vortex 64, as shown by the flow velocity distribution curve 68, and this is considered to promote the generation of the vortex 62 again.

On the other hand, as shown in FIG. 11, when the length R of the acidic water recovery port 20C in the water flow direction is limited,
The vortex 62 becomes much smaller, and the generation of the vortex 64 is also suppressed. The entanglement of the weakly acidic water and the alkaline water in the strongly acidic water is reduced, and the weakly alkaline water and the acidic water are mixed in the strongly alkaline water. Entrapment will be reduced.

The present inventor has stated that the width d of the water passage 36 is constant,
A plurality of electrolytic cells 10 having different lengths R of the acidic water recovery port 20C were manufactured and tested. The total flow rate to the electrolytic cell 10 is 5 l / min, the flow rate of the alkaline water outlet 28 is 4 l / min,
A 12 V DC voltage was applied between the electrode plates while passing water at a flow rate of the acidic water outlet 30 of 1 liter / minute, and the pH of the acidic water outlet 30 and the alkaline water outlet 28 was measured. The results are shown in the graph of FIG. In the graph of FIG. 12, the vertical axis represents pH, and the horizontal axis is the width d of the water passage 36.
(R)
/ C), curve 70 shows the change in the pH value at the alkaline water outlet 28, and curve 72 shows the change in the acidic water outlet 30.
2 shows the change in the pH value in Example 1. As shown in the graph of FIG. 12, according to the test, when the length R in the water flow direction of the acidic water recovery port 20C becomes three times or more the width d of the water passage 36, the acidic water and the alkaline The pH value of the alkaline water at the water outlet 28 approaches neutrality. From this fact, the length R of the acidic water recovery port 20C in the water flow direction is
When the width d exceeds three times the width d of 6, the vortex is generated as shown in FIG. 10, and it is inferred that the acidic water layer and the alkaline water layer are mixed.

When the length of the acidic water recovery port 20C is set so that the ratio R / d is 3 or less, strongly acidic water having a pH of 3.5 is obtained at the acidic water outlet 30 and the alkaline water outlet 2 is provided.
In No. 8, alkaline water having a pH of 9.5 was obtained. pH 3.5
Is considered suitable for sterilization applications.

Although a specific embodiment of the present invention has been described above, the present invention is not limited to this, and various design changes can be made within the scope of the present invention.
For example, the polarity of the electrode plate can be reversed, alkaline water can be taken out from the outlet 30, and acidic water can be taken out from the outlet 28. In the illustrated embodiment, two anode plates are arranged in order to increase the flow rate of the electrolytic cell.
It may be a sheet. In the illustrated embodiment, the slits 16C and 20C acting as ion-rich water recovery ports are provided.
Are provided on the electrode plates 16 and 20, but the slit 16
The electrode plates 16 and 20 may be terminated at C and 20C, and the water passage wall surface 58 downstream of the slits 16C and 20C may be formed by other members.

[0035]

As described above, according to the electrolytic cell structure of the present invention, a laminar flow is formed in the water passages 34 and 36, and while maintaining the laminar flow, the laminar flow is perpendicular to the water flowing direction. A thin layer of ion-rich water (acidic water or alkaline water depending on the polarity of the applied voltage) is separated in different directions and collected from the ion-rich water recovery ports 16C and 20C. At this time, since turbulence is prevented from being generated in the flow of the acidic water (or the alkaline water) flowing into the recovery ports 16C and 20C, strongly acidic (or strongly alkaline) ion-rich water can be recovered. .

Therefore, while enjoying the advantages of a non-diaphragm type electrolytic cell that is hygienic and low in power consumption, it is possible to obtain a strongly acidic and strongly alkaline ion-rich water that cannot be obtained with a conventional non-dielectric membrane type electrolytic cell. Can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating the principle of generating ion-rich water by electrolysis of water.

FIG. 2 is a schematic diagram showing a hydrogen ion concentration distribution in an electrolysis chamber of a diaphragm-free electrolytic cell.

FIG. 3 is a partially cutaway front view of the electrolytic cell of the present invention.

FIG. 4 is an exploded perspective view of the electrolytic cell shown in FIG.

FIG. 5 is a cross-sectional view taken along the line VV of FIG. 3, in which an electrode plate and spacers are omitted for simplification of the drawing.

FIG. 6 is a sectional view taken along the line VI-VI in FIG. 3;

FIG. 7 is a sectional view taken along the line VII-VII of FIG. 3;

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

FIG. 9 is an enlarged sectional view of a portion inside a circle B in FIG. 5;

FIG. 10 is an enlarged schematic diagram showing a water flow when the length of the ion-rich water recovery port is large.

FIG. 11 is an enlarged schematic diagram showing a water flow when the length of the ion-rich water recovery port is limited according to the present invention.

FIG. 12 is a graph showing the results of a test performed while changing the length of the ion-rich water recovery port.

[Description of Signs] 10: Electrolyzers 16, 20: Anode plate 18: Cathode plate 16C, 20C: Acid water recovery port 34, 36: Water passage (electrolysis chamber) 38: First ion-rich water recovery passage (Alkaline water recovery) Passages) 44, 46: Second ion-rich water recovery passage (acid water recovery passage)

──────────────────────────────────────────────────続 き 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-6-246272 (JP, A) JP-A-4-284889 (JP, A) JP-A-4-110189 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) C02F 1/46-1/48

Claims (3)

(57) [Claims] 1. A pair of electrode plates (18, 20) are disposed in parallel and opposed to each other without any intervening diaphragm to form a water passage acting as an electrolytic chamber between the pair of electrode plates. In a non-diaphragm type electrolytic cell (10), which generates ion-rich water by electrolysis of water by passing water through the water passage while applying a DC voltage between the pair of electrode plates: The water channel (36) is defined by two flat wall surfaces (56, 58) extending over the entire length of the water channel, and the downstream end (36A) of the water channel (36) is cut off by the flow passage of the water channel. Opening directly into the first ion-rich water recovery passage (38) having a passage cross-sectional area larger than the area,
Either one of the two wall surfaces (58) is connected to a second ion-rich water recovery passageway (46) upstream of the downstream end (36A) of the water passage, and a recovery opening to the water passage. An opening (20C), and a length (R) of the recovery port (20C) in the water flow direction is set to be three times or less of a distance (d) between the two wall surfaces. Tank. 2. The first ion-rich water recovery passage (38).
The non-diaphragm type electrolytic cell according to claim 1, wherein the second ion-rich water recovery passage (46) recovers acidic water. 3. The first ion-rich water recovery passage (38).
Recovers acidic water, and the second ion-rich water recovery passage (46)
2. A non-diaphragm type electrolytic cell according to claim 1, wherein the alkaline water is recovered.