JP2007301540A - Slightly acidic electrolyzed water generation apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrolytic system in which unevenness in electrolytic reaction is not caused in electrode faces, highly efficient electrolysis is possible, the life of each electrode is elongated to the maximum extent, also back pressure from the side of the dilution water does not apply to the electrolytic cell and original liquid feeding means such as raw liquid piping and a raw liquid pump, the number of parts is reduced, and further expensive parts are not used, for an apparatus in which hydrochloric acid is electrolyzed in a non-diaphragm electrolytic cell, and the generated electrolyte is diluted with water to prepare slightly acidic electrolyzed water. <P>SOLUTION: An electrolytic cell is composed of parallel plate electrodes, the other end of liquid feed piping to the electrolytic cell is joined to an exhaust port of a hydrochloric acid tank, a tube pump is arranged as a liquid feeding means on the liquid feed piping, further, the terminal of the electrolyte exhaust piping in the electrolytic cell is joined to the suction part of an ejector arranged on dilution water piping in such a manner that an electrolyte is sucked from the electrolytic cell with the flow of dilution water as a driving source, and is introduced and mixed into the dilution water. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to an apparatus for electrolyzing hydrochloric acid in a diaphragmless electrolytic cell, diluting the electrolytic solution with water, and generating slightly acidic electrolyzed water having a strong sterilizing power. By devising the system, the device is simplified and the electrolysis efficiency is increased.

When an electrolytic cell with a cylindrical electrode arranged concentrically is used to electrolyze a solution such as hydrochloric acid or salt, and when the electrolyte is diluted with water to produce sterilized water, an aspirator is placed at the electrolyte outlet. Patent Document 1 discloses a method of sucking an electrolytic solution into dilution water with a flow of dilution water.

On the other hand, Patent Document 2 uses a tube pump using an AC motor as a means for supplying a salt solution in a method of electrolyzing salt in a diaphragm electrolytic cell to obtain strongly acidic electrolyzed water only from the anode chamber. A technique for extending the motor life is disclosed.
JP-A-6-99174 Japanese Patent Laid-Open No. 8-238481

However, in the case of an electrolytic cell using cylindrical electrodes arranged concentrically as in Patent Document 1, even if the electrolyte is sucked by an aspirator, a portion that is quickly sucked like the vicinity of the suction port, As in the opposite side of the circumference, the time until the portion far from the suction port is sucked up becomes longer, and the electrolysis time varies depending on the position of the electrolytic cell, which hinders the control of electrolysis.

In addition to the adverse effect on electrolysis control, the electrolysis time non-uniformity seriously affects the electrode life. If there is unevenness in the flow of the liquid inside the electrolytic cell, there will be a place where the electrolyte will be replaced quickly and a place where it will be slow.In the fast place, new electrolyte stock solution will be supplied and electricity will flow easily. Will concentrate. In the place where the current is concentrated, the consumption of the electrode is naturally accelerated, so-called uneven decrease of the electrode occurs, and the life of the electrode is determined by the life of the portion, so that the life is extremely shortened.

Furthermore, when the outlet of the electrolytic cell is sucked, the supply side becomes negative pressure, and when an ordinary diaphragm pump or piston pump is arranged in the electrolytic stock solution supply piping, the electrolytic stock solution is sucked indefinitely, making it difficult to control the electrolysis Become. In order to avoid this, it is necessary to provide a means for closing the raw liquid flow such as a back pressure valve and an open / close valve between the supply pump and the electrolytic cell inlet on the raw solution supply pipe, increasing the number of parts and complicating the control mechanism. End up.

On the other hand, as in Patent Document 2, when a tube pump is used to supply a stock solution, the tube pump has a very low pressure resistance performance, and therefore the system in which the electrolyte and the flow of dilution water meet at the outlet side of the electrolytic cell. Then, it may break without being able to withstand the pressure of dilution water. In order to avoid such a problem, it is necessary to provide a check valve or the like in any of the pipelines until the stock solution supply pump, the electrolytic solution, and the diluted water meet.

In order to avoid excessive pressure on the tube pump, an aspirator or the like is arranged at the outlet of the electrolytic cell as in Patent Document 1, and the stock solution supply pipe is kept at a negative pressure through the electrolytic cell. In the case of Document 2, since a diaphragm type electrolytic cell is used, it is very difficult to control the pressure applied to the front and back of the diaphragm, which is substantially impossible.

Furthermore, since the space between the stock solution pump and the electrolytic cell outlet is filled with a highly chemically corrosive liquid, the materials such as the back pressure valve, stop valve, and check valve disposed there are highly corrosion resistant. It needs to be special, and the price becomes very expensive.

Therefore, the present inventors electrolyzed hydrochloric acid in a non-diaphragm electrolyzer, and diluted the generated electrolyte with water to prepare slightly acidic electrolyzed water. Good electrolysis is possible, and the electrode life is maximized. Further, the back pressure from the dilution water side does not reach the stock solution supply means such as the electrolytic cell, stock solution piping, stock solution pump, etc., and the number of parts is small and expensive. The problem was to provide an electrolysis system that uses no parts.

As a first aspect for solving the above problems, in an apparatus for preparing slightly acidic electrolyzed water by electrolyzing hydrochloric acid in a non-diaphragm electrolyzer and diluting the produced electrolyte with water, the electrolyzer is a parallel plate electrode. The other end of the liquid supply line to the electrolytic cell is joined to the discharge port of the hydrochloric acid tank, and a tube pump is provided as a liquid supply means on the liquid supply line. The end of the electrolyte discharge pipe is joined to the suction part of the ejector arranged so that the electrolyte is sucked from the electrolytic cell by using the flow of the dilution water as a driving source and introduced and mixed into the dilution water on the dilution water pipe. It was decided.

As a result, first, the electrodes are parallel plates, so that the suction of the electrolyte by the ejector is evenly applied to the inside of the electrolytic cell, especially the liquid in the gap between the electrodes, eliminating the problem of uneven electrolysis on the electrode surface. This enabled efficient electrolysis, thereby maximizing the electrode life. In order to further enhance the effect of equalizing the electrolytic reaction on the electrode surface, it is also effective to make the plate electrode have a vertically long structure in the installed state and to have a height: width ratio of 2: 1 or more.

Next, the electrolyte discharge port is joined to the suction port of the ejector, and the electrolyte is sucked by using the force of the dilution water flow. The pressure was avoided. As a result, it becomes possible to use a tube pump with low pressure resistance to supply the stock solution, and further, by using a tube pump, the tube pump is a mechanism that completely closes the pipeline when stopped, A complementary synergistic effect was obtained in that there was no problem even if an extra part such as an on-off valve, a back pressure valve, or a check valve was not provided between the tube pump and the electrolytic cell outlet. It became a technology that was not extended.

As a second aspect for solving the above problem, there is no means for closing the pipe line in the pipe line from the tube pump to the electrolytic cell to the suction port of the ejector. As a result, the pressure loss of the fluid can be eliminated, and the manufacturing cost can be reduced by reducing the number of parts.

As a third aspect for solving the above-mentioned problem, the tube pump is operated by a control that starts when the electrolysis current falls below the set lower limit and stops when the electrolysis current exceeds the set upper limit. . The purpose is to keep the electrolytic reaction inside the electrolytic cell as uniform as possible in terms of time and to keep the component of the slightly acidic electrolyzed water discharged constant. The amount of hypochlorous acid, which is an active ingredient for sterilization of slightly acidic electrolyzed water, depends on the hydrochloric acid concentration in the electrolytic cell and the current value. To keep both constant, the current value must be kept within a certain range. It was decided to control. Since the current value depends on the hydrochloric acid concentration in the electrolytic cell, the hydrochloric acid concentration is also controlled in a certain range by controlling the current value within a certain range. Both the hydrochloric acid concentration and the current value are kept within a certain range by this method.

電解電流値は高くすると生成する次亜塩素酸の量は増えるが電極寿命は短くなる。電極の単位面積当たりの電流値である電流密度を高くすると電極や近傍の液体が加熱され、電極消耗の最大の原因となり、特に５０℃を超えると急激に電極の消耗が激しくなることが分かった。電極の温度は電流値と電解槽内の液体流量によって決まるが、目標の濃度を保った微酸性電解水を生成する条件としての流量では、電流密度を５Ａ／１００ｍ^２程度を上限とすれば良いことを経験的に知った。そこで、その電流密度の９０％を下限値とし、１１０％を上限値とすることによって、電極の消耗を抑え、かつ次亜塩素酸の発生量を最大にできることも確認した。上記式は下限電流密度４．５Ａ／１００ｍ^２、上限電流密度５．５Ａ／１００ｍ^２を、実際の電極面積に換算する式である。As a fourth aspect for solving the above problem, the electrolytic current value A in the third aspect is controlled between the left side and the right side shown in the following equation.

Increasing the electrolysis current value increases the amount of hypochlorous acid produced, but shortens the electrode life. It has been found that increasing the current density, which is the current value per unit area of the electrode, heats the electrode and the liquid in the vicinity, causing the maximum consumption of the electrode, especially when the temperature exceeds 50 ° C. . The temperature of the electrode is determined by the current value and the liquid flow rate in the electrolytic cell, but the flow rate as a condition for generating slightly acidic electrolyzed water maintaining the target concentration may be set such that the current density is about 5 A / 100 m ² as the upper limit. I knew this from experience. Therefore, it was also confirmed that by setting 90% of the current density as the lower limit and 110% as the upper limit, the consumption of the electrode can be suppressed and the amount of hypochlorous acid generated can be maximized. The above formula is a formula for converting the lower limit current density 4.5 A / 100 m ² and the upper limit current density 5.5 A / 100 m ² into the actual electrode area.

As a fifth aspect for solving the above problems, the concentration of hydrochloric acid supplied to the electrolytic cell is 0.5% or more and less than 10% by weight. If it is 0.5% or less, it is necessary to increase the electric resistance and increase the electrolysis voltage, which causes generation of impurities, and the lower limit is 0.5%. Since the upper limit of the concentration employs a method of supplying the electrolytic cell as it is without diluting, the upper limit is set to less than 10% which is the maximum concentration for minimizing the chemical erosion action on the electrode.

As a sixth aspect for solving the above-described problem, the trace amount of inorganic substance contained in hydrochloric acid is sodium chloride and at least one compound selected from potassium compounds, lithium compounds, calcium compounds, magnesium compounds, and barium compounds. It was. Food additive-standard hydrochloric acid and hydrochloric acid diluted with potable water etc. inherently contain trace amounts of inorganic substances. This aspect means that water containing a large amount of minerals, such as hard water or deep sea water, is used as water used for dilution in order to actively use inorganic substances contained in trace amounts. When hydrochloric acid is electrolyzed and the electrolyte is diluted with water, hydrochloric acid is generated simultaneously with hypochlorous acid, and the pH of the liquid may be abnormally lowered. If the hydrochloric acid contains an alkali metal or alkaline earth metal in advance, a part of the generated hydrochloric acid is neutralized by the alkali generated by electrolysis to prevent an abnormal pH drop.

According to the present invention, in an apparatus for preparing hydrochloric acid electrolyzed water by electrolyzing hydrochloric acid in a non-diaphragm electrolytic cell and diluting the generated electrolytic solution with water, an electrolytic reaction is not uneven in the electrolytic cell, and efficient electrolysis is performed. It was possible to maximize the electrode life by making it possible, selecting the optimum current density, and using the optimum concentration of hydrochloric acid. In addition, the back pressure from the dilution water side does not reach the stock solution supply means for the electrolytic cell, stock solution piping, stock solution pump, etc., and the tube pump is used for the stock solution pump. The structure does not need to be used. As a result, it has become possible to provide a slightly acidic electrolyzed water generator that is inexpensive, has few failures, and has a long service life.

The best mode for carrying out the present invention will be described with reference to the flow diagram of Hokuetsu apia 60 shown in FIG. The electrolytic cell 1 and the ejector 2 are combined together to form an electrolytic unit 12. An electrolytic solution discharge hole 9 is provided at the top of the electrolytic cell and is connected to the suction portion of the ejector. When dilution water is supplied from the dilution water pipe 6, the electrolyte is sucked from the discharge port to the dilution water side by the force of the flow, diluted with dilution water to become slightly acidic electrolyzed water, and discharged from the slightly acidic electrolyzed water discharge port 7. Is done. The hydrochloric acid supply pipe 4 is connected from a hydrochloric acid tank 8 through a tube pump 3 to a hydrochloric acid supply port 14 provided in the lower part of the electrolytic cell. The output terminal of the DC power supply 11 is electrically joined to the electrode 5 built in the electrolytic cell, supplies a direct current, and electrolyzes hydrochloric acid supplied inside the electrolytic cell. A current sensor 13 is disposed on the DC current supply wiring. When the current value falls below a set lower limit value, a tube pump start signal is generated by a controller (not shown), and the set upper limit value is set. If this is exceeded, a tube pump stop signal is generated.

In this apparatus, hydrochloric acid diluted to 3% with hard water was used, diluted water was flowed at 60 L / h, and electrolysis current was controlled at 1.5 A ± 10% to generate slightly acidic electrolyzed water. The slightly acidic electrolyzed water obtained at 60 L per hour had an effective chlorine concentration of 20 ppm and a pH of 5.8. The consumption of hydrochloric acid was about 30 ml per hour.

It is a flowchart of a slightly acidic electrolyzed water generating apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrolysis tank 2 Ejector 3 Tube pump 4 Hydrochloric acid supply line 5 Electrode 6 Dilution water supply line 7 Slightly acidic electrolyzed water outlet line 8 Hydrochloric acid tank 9 Electrolyte outlet 10 Electrolyte flow direction 11 DC power supply 12 Electrolytic unit 13 Current sensor 14 Hydrochloric acid supply port

Claims (6)

An apparatus for preparing slightly acidic electrolyzed water by electrolyzing hydrochloric acid in a non-diaphragm electrolytic cell and diluting the produced electrolyte with water,
I. The electrolytic cell is composed of parallel plate electrodes,
B. The end of the liquid supply line to the electrolytic cell is connected to the discharge port of the hydrochloric acid tank, and a tube pump is provided as a liquid supply means on the liquid supply line,
C. The end of the electrolytic solution drain line of the electrolytic cell is an ejector disposed on the diluted water line so that the electrolytic solution is sucked from the electrolytic cell using the flow of the diluted water as a drive source, and is introduced and mixed into the diluted water. Connected to the suction part of
D. Slightly acidic electrolyzed water generator characterized in that hydrochloric acid contains a trace amount of inorganic substances 2. The slightly acidic electrolyzed water generating device according to claim 1, wherein there is no pipe closing means in a pipe line from the tube pump through the electrolytic cell to the suction part of the ejector. The operation of the tube pump is performed by control that starts when the electrolysis current falls below a set lower limit value and stops when the electrolysis current exceeds a set upper limit value. Slightly acidic electrolyzed water generator The electrolytic current value A according to claim 3 is represented by the following formula:
(N × S × 4/100) <A <(N × S × 6/100)

4. The slightly acidic electrolyzed water generating apparatus according to claim 1, wherein the apparatus is controlled within a range of 5. The slightly acidic electrolyzed water generating device according to claim 1, wherein the concentration of hydrochloric acid is 0.5% or more and less than 10% by weight. The fine trace according to any one of claims 1 to 5, wherein the trace amount of inorganic substance is at least one of sodium chloride, potassium compound, lithium compound, calcium compound, magnesium compound and barium compound. Acidic electrolyzed water generator

Images