JPH0810770A - Diaphragmless type electrolytic cell for forming ion rich water - Google Patents

Abstract

PURPOSE:To provide a diaphragmless electrolytic cell capable of effectively removing the scale, such as calcium carbonate, deposited on electrode plates by impression of a reverse polarity voltage and prolonging the life of an electrolytic cell by improving the electrolytic cell of a diaphragm less type for forming ion rich water. CONSTITUTION:Inlets 34A, 36A of the water flow paths of the electrolytic cell 10 are connected to a distributing passage 32 having a flow passage area larger than the flow passage sectional area thereof and the side walls 32A, 32B of this distributing passage are inclined toward the inlets 34A, 36A of the water flow path. Water forms a laminar flow soon after flowing into the inlets 34A, 36A. The region DT where the turbulence is generated in the inlets 34A, 36A of the water flow path is then minimized. The scale is effectively dissolved by the layer of the strongly acidic water formed at the boundary between the cathode plates and water.

Description

Detailed Description of the Invention

[0001]

[Object of the invention]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolytic cell for electrochemically producing ion-rich water such as alkaline water or acidic water by electrolyzing water. The present invention particularly relates to an electrolytic cell structure capable of effectively removing scale such as calcium carbonate deposited on an electrode plate of an electrolytic cell.

[0002]

2. Description of the Related Art Hydroxide (OH ^- ) ^- rich alkaline water is conventionally called "alkali ionized water".
It is considered that when it is used as a drink, it has an effect of promoting health, and when it is used for tea, coffee, or the like, it has an effect of enhancing the taste. In addition, hydrogen ions (H ⁺ )
Rich acidic water is known to be suitable for boiling noodles and washing the face, and acidic water having a high hydrogen ion concentration is useful for sterilizing and sterilizing kitchen cutting boards and cloths.

In order to obtain such alkaline water or acidic water, an ion-rich water generator (which is often called an ion water generator in the industry) has been conventionally used. This device utilizes electrolysis of water and has an electrolytic cell equipped with an anode and a cathode. When a DC voltage is applied between the electrodes, at the interface between the anode and water, OH ⁻ present in water is oxidized by giving electrons to the anode due to ionization of water,
It becomes oxygen gas and is removed from the system. As a result, the H ⁺ concentration is increased 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, is reduced to hydrogen, and is removed as hydrogen gas, so that the OH ⁻ concentration is increased, and OH ⁻ rich alkaline water is present on the cathode side. Is generated.

In a conventional general electrolytic cell, in order to prevent alkaline water and acidic water produced by electrolysis from mixing with each other and take them out separately, an anode as shown schematically in FIG. A water-impermeable and ion-permeable diaphragm 3 is arranged between the plate 1 and the cathode plate 2, and the electrolytic chamber is divided into an alkaline water flow path 4 and an acidic water flow path 5 by this diaphragm (this type). The electrolyzer will be referred to as the "diaphragm type"
Called electrolyzer).

With the use of the electrolytic cell, precipitates (scales) 6 such as calcium carbonate, calcium hydroxide and magnesium hydroxide adhere to the alkaline water flow path. Referring to FIG. 2, the mechanism of scale deposition will be described taking the case of calcium carbonate as an example. FIG. 2 shows the relationship between the apparent solubility of calcium carbonate and pH. Under acidic conditions, calcium carbonate is dissolved in water in the form of calcium ions, but above pH 8, the solubility drops sharply, causing precipitation of calcium carbonate. In the diaphragm type electrolytic cell, as shown in FIG. 1, the scale tends to be preferentially deposited on the diaphragm 3 rather than on the cathode plate 2. It is considered that this is because the cathode plate generally has a polished surface, whereas the diaphragm is porous and easily causes precipitation. Since precipitates such as calcium carbonate have an insulating property, they increase the electric resistance to deteriorate the electrolysis efficiency of the electrolytic cell and increase the water flow resistance. Therefore, unless the scale is removed, the electrolytic cell becomes unusable in a very short time.

Therefore, in the prior art, it is proposed that the polarity reversing switch 7 is operated to apply a voltage having a polarity opposite to the polarity during normal use to the electrode plate to dissolve and remove the precipitate. (For example, JP-A-51-775
No. 84, No. 55-91996, No. 59-189871, No. 1, JP-A-1
-203097). This technology is commonly used in the industry as "reverse electric cleaning".
It is also said. The principle of reverse electrolysis cleaning is that if the original alkaline water flow path is made acidic by applying a reverse polarity voltage,
As can be seen from the above, scales such as calcium carbonate become ions and dissolve again in water.

However, as can be seen from FIG. 1, the diaphragm 3
Is more or less distant from the electrode plate, and the strongly acidic water generated along the surface of the original cathode plate (which becomes the anode when a reverse polarity voltage is applied) 2 flows along with the water flow, thus Since it is impossible to reach the diaphragm, the diaphragm cannot be made sufficiently acidic and the scale deposited on the diaphragm cannot be rapidly dissolved. When a reverse polarity voltage is applied to the electrolytic cell when water is stopped, hydrogen ions generated on the surface of the original cathode plate (anode plate when the reverse polarity voltage is applied) 2 permeate through the diaphragm 3 and diffuse. Since the generated acidic water and alkaline water are neutralized, it is still impossible to make the diaphragm strongly acidic. The present inventor has tested and found that the original alkaline water flow path 4 is applied even if a reverse polarity voltage is applied.
The internal pH never became lower than 3, and the application of the reverse polarity voltage was continued for about 2 days, but the scale was not removed.

As described above, in the "diaphragm type" electrolytic cell, it is difficult to electrochemically remove the scale even if the so-called reverse electrolysis cleaning is performed. Therefore, unless the scale is manually removed by periodically disassembling the electrolytic cell, the life of the electrolytic cell is only half a year to one year. In addition, bacteria are easily propagated in the diaphragm, which is not hygienic.

In order to solve the above problems of the diaphragm type electrolytic cell,
JP-A-4-284889 proposes that the electrolytic cell has a structure without a diaphragm. This type of electrolytic cell is referred to herein as a "diaphragmless" electrolytic cell. In this electrolytic cell, the electrode plates are arranged with a narrow gap so that water flows through the water passage between the electrode plates while forming a laminar flow. Therefore, the alkaline water and the acidic water generated by electrolysis can be separated without providing a diaphragm.

In this non-diaphragm type electrolytic cell, since there is no diaphragm, scale does not adhere to the diaphragm. Therefore, there is an advantage that the scale does not easily adhere. The scale is mainly deposited on the cathode plate, but the amount thereof is significantly smaller than that in the diaphragm type electrolytic cell. In addition, since there is no diaphragm that causes bacterial growth, it is extremely hygienic.

In the "diaphragm-free" electrolytic cell of JP-A-4-284889, as in the case of the "diaphragm-type" electrolytic cell, a reverse polarity voltage is applied for scale removal (so-called reverse electrolysis cleaning). It is like this.

[0012]

SUMMARY OF THE INVENTION
The membrane-less electrolytic cell structure disclosed in 4-284889 has room for improvement from the viewpoint of removing scale by applying a reverse polarity voltage. That is, even if the reverse polarity voltage is periodically applied, the scale is not completely removed in the inlet area of the water passage, and the scale tends to accumulate in the inlet area of the water passage as the electrolytic cell is used. .

This is considered to be due to the following reason. That is, the reverse polarity voltage is applied during water passage to the electrolytic cell, but the cross-sectional shape of the distribution passage (tank chamber) is such that the cross-sectional area of the flow passage decreases sharply from the distribution passage to the inlet of the water passage. Therefore, at the entrance of the channel, there is a turbulent flow region where a stable laminar flow has not yet been established over a relatively long range. In this turbulent flow region, strong acidic water cannot be generated on the surface of the electrode plate, so it is difficult to effectively dissolve the scale.

It is an object of the present invention to improve the diaphragmless electrolytic cell disclosed in Japanese Patent Laid-Open No. 4-284889 and to effectively prevent the scale from being deposited over the entire length of the electrode plate. It is to provide a diaphragm type electrolytic cell.

[0015]

Configuration of the Invention

SUMMARY OF THE INVENTION Means for Solving the Problems and the Outline of Action The present invention relates to a diaphragmless electrolytic cell in which an inlet of a water passage is connected to a distribution passage having a passage cross-sectional area larger than that of the water passage. However, the sectional shape of the distribution passage is characterized in that the turbulent flow region generated in the inlet region of the water passage is determined to be the minimum. Preferably, the side wall of the distribution passage is sloped towards the inlet of the water passage.

With such a cross-sectional shape, the water flowing into the water passage from the distribution passage quickly forms a stable laminar flow and establishes the laminar flow over substantially the entire length of the water passage. Therefore, when a voltage of reverse polarity is applied, the interface between the cathode plate (which becomes an anode when a reverse voltage is applied) and water has a layer of acid water of maximum strength over almost the entire area from the inlet region of the water passage to the outlet. Is generated. This strongly acidic water layer dissolves the aggregated precipitates such as calcium carbonate deposited on the surface of the cathode plate in the previous ion-rich water production step along the interface between the cathode plate and water to form the cathode plate and the aggregated precipitates. Loosen the physical-chemical connection between. The aggregated precipitate thus released from the cathode plate is separated from the cathode plate by the action of running water and washed away. In this way, aggregated precipitates such as calcium carbonate are effectively removed, and scale accumulation is prevented over almost the entire length of the electrode plate, so that the life of the electrolytic cell can be remarkably extended.

[0017]

EXAMPLES FIGS. 3 to 9 show examples of the electrolytic cell of the present invention. Mainly referring to FIGS. 3 and 4, the diaphragmless electrolytic cell 10 has a vertically long housing 12. In this 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 while sandwiching a plurality of resin spacers 22. , The cover 24 is liquid-tightly screwed to the case 14. By arranging the anode plates 16 and 20 on both sides of the cathode plate 18, the electrolytic cell 10 has a so-called double cell structure. By effectively using both sides of the cathode plate 18, the processing capacity is doubled. It can be stored in a small space.

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 distance is about 0.5 mm. It is like this. Preferably,
The electrode plates 16, 18 and 20 are manufactured by coating a titanium metal plate with platinum. Terminals 16A, 18A and 20A are fixed to the electrode plates 16, 18 and 20, respectively, so that they can be connected to a DC power source (not shown).

As can be seen from FIG. 4, the case 14 has a clean water inlet 26, an alkaline water outlet 28, and an acidic water outlet 30. The clean water inlet 26 communicates with a clean water distribution passage 32 having a substantially triangular cross section. This clean water distribution passage 32
As can be seen from FIG. 5, the case 14 and the cover 2 are
4 and extends over the entire vertical length of the electrode plate. When using the electrolytic cell 10, the clean water inlet 26 can be connected to a water pipe by a hose or the like. Alternatively, the electrolytic cell 10 is connected to the downstream of the water purifier, and the water purified by the water purifier is supplied to the upper water inlet 26 of the electrolytic cell 10.
May be introduced into.

As can be seen from the enlarged sectional views of FIGS. 8 and 9, there is a first space between 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 act as an electrolysis chamber. Each of the water passages 34 and 36 extends horizontally, for example, five spacers 2.
It is divided into 4 upper and lower sub water passages by 2.

As can be seen from FIG. 9, these water passages 3
The inlets 34A and 36A of 4 and 36 have a flow passage cross-sectional area larger than their flow passage cross-sectional area.
It is in communication with. Therefore, the clean water flowing down from the clean water inlet 26 along the distribution passage 32 is supplied to the respective water passages 34 and 3.
It is distributed to four sub water channels 6 and flows in the horizontal direction as shown by the arrow in FIG.

As shown in FIGS. 9 and 10, the side walls 32A and 32B of the distribution passage 32 have inlets 34A of the water passage.
And 36A and is inclined toward the distribution passage 32
The water smoothly flows from the inlet to the inlets 34A and 36A of the water passage. Because it has such a shape,
The water flowing into the water passage inlets 34A and 36A is
As shown in FIG. 5, a laminar flow is formed while flowing in the relatively short turbulent flow generation region D _T.

As shown in FIGS. 5 and 8, the downstream end portions of the water passages 34 and 36 acting as an electrolysis chamber have an almost pentagonal cross section of an alkaline water recovery passage 38 formed by the case 14 and the cover 24. It is open to the public. The alkaline water recovery passage 38 communicates with the alkaline water outlet 28, and, like the clean water distribution passage 32, extends over the entire vertical length of the electrode plate. As can be seen clearly from FIGS. 5 and 8, the flow passage cross-sectional area of the alkaline water recovery passage 38 is also sufficiently larger than the flow passage cross-sectional areas of the water passages 34 and 36, so that the flow passage does not generate turbulence. The alkaline water is smoothly discharged from the ends of the water passages 34 and 36 toward the alkaline water recovery passage 38.

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

As can be seen from FIGS. 3 and 8, in the illustrated embodiment, the anode plates 16 and 20 are provided with slits 16C and 20C, respectively, which act as acidic water recovery ports, and the slits 16C and 20C are formed. The water that has passed through flows into the acidic water recovery passages 44 and 46. As can be seen from FIGS. 5 and 8, the capacity of the acidic water recovery passages 44 and 46 is sufficiently large with respect to the flow passage cross-sectional areas of the slits 16C and 20C, and the acidic water recovered from the slits is It smoothly flows into the acidic water recovery passages 44 and 46 without generating turbulent flow. Slits 16C and 2
The acidic water flowing out from 0C is collected in the acidic water recovery passages 44 and 46 over substantially the entire length in the vertical direction of the anode plate,
From there, it is sent to the acidic water outlet 30.

When alkaline or acidic ion-rich water is produced using this electrolysis tank 10, the upper water inlet 26 of the electrolysis tank can be connected to a tap of a tap water by a hose or the like, and an alkaline water outlet 28 and an acidic water outlet are provided. Conventional flow control valves 50 and 52 may be connected to the water outlet 30, respectively. The clean water introduced from the clean water inlet 26 is
As described above, the distribution passage 32 allows the electrode plates 16, 1
Water channels 34 and 3 over the entire length in the vertical direction of 8 and 20
6 are evenly distributed to the inlets (upstream end), and the water passages 34
And flows horizontally into 36.

When a DC voltage of, for example, about 12 V is applied between the cathode plate 18 and the anode plates 16 and 20, water is passed through the water passages 34 and 36 to cause electrolysis to proceed. Alkaline water is produced along the surface and acidic water is produced along the surfaces of the anode plates 16 and 20. The alkaline water is collected at the outlet 28 of the electrolyzer and the acidic water is collected at the outlet 30.

With the generation of ion-rich water, the cathode plate 18
Aggregated precipitates such as calcium carbonate are deposited on both surfaces of. This aggregated precipitate will result in a stubborn coating if not removed quickly. Therefore, by switching the reversing switch at an appropriate time, a positive voltage is applied to the cathode plate 18 and a negative voltage is applied to the anode plates 16 and 20. As described above with reference to FIG. 10, in the electrolytic cell structure of the present invention, the turbulent flow generation region D _T is negligibly short, so that a laminar flow is formed over almost the entire length of the water passages 34 and 36, and the cathode plate On the surface of 18, a layer of strongly acidic water is formed over almost the entire length. This strongly acidic water layer dissolves agglomerated precipitates such as calcium carbonate deposited on the surface of the cathode plate in the ion-rich water producing step.

FIG. 11 shows a sectional shape of a distribution passage of a conventional diaphragmless electrolytic cell. In this electrolytic cell, since the cross-sectional area of the flow passage is rapidly reduced from the distribution passage to the water passage, the turbulent flow generation region _DT becomes longer than that in the structure of FIG.

Experimental Example An electrolytic cell having the structure shown in FIG. 10 and an electrolytic cell having the structure shown in FIG. The width of the electrode plate was about 5 cm.
The water of Chigasaki city was electrolyzed while applying a reverse polarity voltage for about 15 seconds every about 4 minutes of water flow. Total operating time is about 2
When it reached 00 hours (corresponding to about 7 years under normal use conditions of the electrolytic cell at home), the electrolytic cell was disassembled, and the state of deposition of deposits on the surface of the cathode plate 18 was examined. The state of deposition on the surface of the cathode plate 18 of each electrolytic cell is shown in FIG.
And shown in FIG. 12 corresponds to the electrolytic cell shown in FIG. 10, and FIG. 13 corresponds to the electrolytic cell shown in FIG.

As can be seen by comparing FIGS. 12 and 13, in the case of the electrolytic cell structure shown in FIG. 11, deposits are deposited over a width of about 1 cm from the inlet of the water passage,
In this region, it is shown that the precipitate did not dissolve even when a voltage of opposite polarity was applied. This is considered to be due to the generation of turbulence. On the other hand, as can be seen from FIG. 12, in the case of the electrolytic cell structure of FIG. 10, no deposit was observed at the inlet of the water passage even after the operation of the electrolyzer for about 7 years, and Precipitates have been removed over the entire length.

FIG. 14 shows a modification of the housing 12 of the electrolytic cell. The same components as those shown in FIGS. 3 to 5 are designated by the same reference numerals, and the description thereof will be omitted. In this structure, for example, two pillars 60 are formed in the case 14 at the center of the housing 12 in the vertical direction, and the center part of the cover 24 in the left-right direction is fixed to these pillars 60 by screws 62. According to this structure, the case 14 and the cover 24 can be prevented from bulging outward due to water pressure, and the gap between the electrode plates can be maintained constant.

Although specific embodiments of the present invention have been described above, the present invention is not limited thereto. For example,
The electrolytic cell has been described as having a double cell structure including the central electrode plate 18 and the two side electrode plates 16 and 20.
One of the side electrode plates may be eliminated, or the number of electrode plates may be further increased. Further, although it has been described that the central electrode plate 18 serves as a cathode plate and the side electrode plates 16 and 20 serve as anode plates, in order to obtain acidic water at the outlet 28 of the electrolytic cell and alkaline water at the outlet 30, The voltage may be applied so that the central electrode plate 18 serves as an anode plate and the side electrode plates 16 and 20 serve as cathode plates. Also in that case, when removing the scale, a voltage reverse to that at the time of use is applied.

[0034]

According to the present invention, the inlet region 34 of the water passage.
The turbulent flow generation regions D _T in A and 36A are minimized, and a laminar flow is formed over almost the entire area from the inlet to the outlet of the water passage, so that aggregated precipitates such as calcium carbonate deposited on the surface of the cathode plate are removed. It can be effectively removed by applying a reverse polarity voltage. Therefore, the life of the electrolytic cell can be remarkably extended.

Under normal use conditions, scale deposits can be prevented over a period of several years or longer, so that maintenance of the electrolytic cell is substantially unnecessary.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a prior art “diaphragm” electrolytic cell.

FIG. 2 is a graph showing the relationship between the apparent solubility of calcium carbonate and pH.

FIG. 3 is an exploded perspective view of the electrolytic cell of the present invention.

4 is a cross-sectional view taken along the line IV-IV of FIG. 3, showing an assembled state of the electrolytic cell.

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

6 is a cross-sectional view taken along the line VI-VI of FIG.

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

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

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

10 is an enlarged schematic view of a portion inside a circle A in FIG.

FIG. 11 is a schematic view similar to FIG. 10, showing an electrolytic cell having a conventional structure.

FIG. 12 is a photograph showing a deposited state of a deposit on a cathode plate of the electrolytic cell shown in FIG.

FIG. 13 is a photograph showing a deposited state of a deposit on a cathode plate of the electrolytic cell shown in FIG.

14 is a cross-sectional view taken along line XIV-XIV of FIG. 4, showing a modified form of the electrolytic cell housing, omitting the electrode plates and spacers.

[Explanation of symbols]

 10: non-diaphragm type electrolytic cell 16, 18, 20: electrode plate 32: distribution passage 34, 36: water passage 34A, 36A: inlet area of water passage

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hideho Miyahara Inventor Hidehide Miyahara, 2-1-1 Nakajima, Kokurakita-ku, Kitakyushu, Fukuoka Prefecture (72) Inventor Shigeru Ando 2 Nakajima, Kokurakita-ku, Kitakyushu, Fukuoka 1st-1st Totoki Equipment Co., Ltd.

Claims (2)

[Claims] 1. A water passage functioning as an electrolytic chamber is provided between the anode plate and the cathode plate by arranging a pair of the anode plate and the cathode plate in close proximity to each other and without interposing a diaphragm and in parallel to each other. Ion-rich water is formed by connecting the inlet of the water passage to a distribution passage having a flow passage cross-sectional area larger than the flow passage cross-sectional area of the water passage and electrolyzing the water while passing water through the water passage. In a non-diaphragm type electrolytic cell adapted to produce: a non-diaphragm type electrolytic cell characterized in that a cross-sectional shape of the distribution passage is determined so that a turbulent flow region generated in an inlet region of a water passage is minimized. Electrolyzer. 2. The diaphragmless electrolytic cell according to claim 1, wherein a side wall defining the sectional shape of the distribution passage is inclined toward the inlet of the water passage.