JP2001254096A - Cleaning fluid and washing apparatus using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a washing method which is small in the environmental load, high in the safety of a cleaning fluid as such for the human body, and simultaneously capable of effecting safe and hygienic washing and sterilization without causing pollution and eutrophication of the washed waste water. SOLUTION: Since the soiling of an object to be washed is swollen/dissociated with the use of an alkaline buffer solution formed by electrolysis to float a soiling component mainly having an oil component in the solution, the washed waste water contains no surface active agent. Further, by adding a substance capable of forming hypochlorous acid having sterilization effect by electrolysis to cause the substance to form the hypochlorous acid in the buffer solution by electrolysis, the washing effect and the sterilization effect on the object to be washed are more improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a cleaning method,
This relates to cleaning that does not cause environmental pollution due to wastewater after cleaning.Specifically, even when the cleaning liquid does not contain a so-called surfactant such as a synthetic detergent or soap, sufficient cleaning power and sterilizing power are maintained. The present invention relates to a cleaning liquid obtained by the above method and a cleaning apparatus using the cleaning liquid.
Specifically, the present invention relates to a cleaning apparatus using an alkaline buffer cleaning solution and a hypochlorous acid solution obtained by electrolyzing a mixture of an aqueous solution containing an alkali metal ion and an inorganic chloride.

[0002]

2. Description of the Related Art Generally, in various manufacturing processes represented by the food industry, washing is repeatedly performed in various situations. Conventionally, such washing has a surfactant action,
In addition, various detergents based on biodegradation have been used. Further, even in ordinary households, washing is performed by a method according to this method in the fields of washing foods, dishes and clothes.

[0003] In a commercially available dishwashing and disinfecting apparatus, various stains such as oils and fats, proteins, starch and the like adhering to the dishes are washed off using a detergent or powdered soap. In many cases, the sterilization uses a thermal action such as hot air or hot water.

FIG. 1 shows an example of a conventional dishwasher in a general household. In FIG. 1, when a certain amount of water is supplied into a washing tank 1 in which a detergent containing sodium percarbonate or sodium perborate, a protease, and a starch-degrading enzyme is previously supplied, a washing pump 2 is started, and washing is performed. Water is sucked into the washing pump 2 through the filter 3, pressurized and jetted from the nozzle 4. The cleaning water sprayed from the nozzle 4 cleans the tableware 6 placed on the tableware basket 5 and then accumulates at the bottom of the cleaning tank 1, is sucked into the cleaning pump 2 again, and circulates in the cleaning tank 1. At this time, the washing water is heated and heated by the heater 7. In addition, the dirt components such as residual vegetables adhered to the tableware 5 are washed off by the washing water, and are captured and removed by the filter 3 when sucked into the washing pump 2 together with the washing water.

After the washing is completed, the washing water is discharged out of the apparatus by a drain pump. After that, a certain amount of water is supplied again into the washing tank 1, and rinse washing (washing by circulating only water without adding a detergent) is performed as in the case of washing, and draining is performed again after the rinse washing is completed. . This rinsing step is generally performed a plurality of times. Thereafter, the inside of the washing tank 1 and the tableware 6 are dried by the heater 7 and the blowing fan 8 for drying, and the entire process is completed. The above-mentioned sodium percarbonate and sodium perborate contained in the detergent have the effect of bleaching the tea astringent adhering to the dishes, decomposing odors derived from food stains, and eliminating bacteria at the same time as washing.

Further, in the electronic industry, a cleaning step of a printed board or a glass substrate having organic oil stains or inorganic stains such as metal powders and minerals adhered to the surface is required.
Conventionally, such cleaning has been performed using a chlorine-based (eg, carbon tetrachloride), chlorofluorocarbon-based solvent, acetone-alcohol-based organic solvent, or a surfactant.

[0007] However, in the above-mentioned cleaning method using a surfactant and further using a cleaning method using an organic solvent, a large amount of the organic solvent or the surfactant remains in the cleaning wastewater, and there is a problem such as eutrophication of rivers and the ocean. Etc., causing water pollution. In addition, a large amount of electricity is consumed to generate hot water, which causes an increase in the amount of oil required for power generation and, consequently, carbon dioxide emission. At the same time, chlorine-based, chlorofluorocarbon-based, and organic solvent-based solvents have caused problems such as adverse effects on the human body, especially the global environment and environmental hormones.

In recent years, an electrolyzed water generator for generating acidic water and alkaline water has been developed. The alkaline water generated by this device has a function of decomposing proteins and fats and oils, and the acidic water has a sterilizing and bleaching function. Therefore, various cleaning apparatuses have been proposed that make effective use of these characteristics.

[0009] For example, in Japanese Patent Application Laid-Open No. 8-71131, a positive electrode plate and a negative electrode plate are provided in an electrolytic bath filled with an electrolytic solution, and an object to be cleaned is immersed. A cleaning apparatus has been proposed which sterilizes and cleans an object to be cleaned while applying a DC voltage to an electrolyte by applying a voltage therebetween.

Japanese Patent Application Laid-Open No. Hei 8-47473 proposes a dishwashing apparatus equipped with a water generating apparatus capable of generating alkaline water and acidic water by electrolyzing tap water. According to this, it is said that alkaline water and acidic water can be selectively supplied to the cleaning tank, and cleaning using alkaline water and sterilization using acidic water can be performed.

[0011] In addition, as a sterilization method, methods such as sterilization cleaning, heat sterilization, and steam sterilization using electrolytic chlorinated water, ozone water, a bactericide, and ultraviolet sterilization are disclosed. Regarding this, for example, Japanese Unexamined Patent Publication No. Hei 5-13768
9, JP-A-8-228603, JP-A-8-228603
228603 and the like.

[0012]

In particular, detergents used for dishwashers generally use strong synthetic detergents, and therefore, a large amount of detergent components are contained in wastewater, and therefore sewage treatment plants and the like There is also a concern that bacterial treatment may not be able to keep up with the environment, and if untreated waste is generated, it may be released to rivers and oceans as it is, which may have a serious impact on environmental problems.

The present invention has been made to solve the above-mentioned problems, and has a small environmental load, a high safety of the cleaning liquid itself to the human body, and a stable and sanitary cleaning. An object of the present invention is to provide a cleaning liquid that is less likely to cause contamination and eutrophication, and a cleaning apparatus using the same.

However, in the conventional configuration, for example,
As described in Japanese Patent Publication No. 137689, sodium bleaching of tableware, odor decomposition of food and bactericidal action all depend on detergents, and sodium percarbonate and sodium perborate having relatively weak oxidizing action in the detergents. , The effect of bleaching and deodorizing tableware was insufficient. In addition, when used for cleaning foods, if the rinsing after cleaning is insufficient, or in depressions often seen when washing raw vegetables and fruits, carbonic acid, which is a decomposition product of the compound in the detergent, There is a problem that salts and borates easily remain after washing.

[0015] In the conventional dishwasher, sterilization under the condition that the temperature is maintained at 75 ° C or more for 2 minutes or more is performed in the final rinsing step. Specifically, at present, in household dishwashers, rinsing water heated to 75 ° C. or higher is sprayed on the tableware for 2 minutes or more, and the temperature of the tableware itself is raised to sterilize the tableware. For this reason, it is necessary to supply a large amount of electric energy to heat the rinsing water to 75 ° C., which leaves a problem as an energy saving measure.

[0016] Other sterilization and cleaning methods still have problems in terms of sustained sterilizing power and stability of the sterilizing solution. Hypochlorous acid rapidly decomposes in an acidic state of pH 5 or less, and cannot exist stably for a long period of time. It is also known that under strong alkaline conditions of pH 12 or more, the reaction of generating effective active chlorine having a bactericidal action by decomposition does not proceed slowly. The present invention solves such a problem by utilizing the buffering action of a buffer solution generated by electrolysis, and the decomposition reaction of hypochlorite ion for manifesting a bactericidal action becomes extremely stable. It is possible to stabilize the pH of the washing solution in the pH range where it occurs. Specifically, by maintaining the solution in a pH range of about 9 to 6, the effective chlorine concentration is maintained at a concentration sufficient for manifesting the bactericidal action, and thus the bactericidal effect is maintained at a high level.

[0017]

As described above, various prior arts have been disclosed for cleaning and sterilization. In addition, some hypochlorite ions and the like have already been actually used as a method for sterilizing and cleaning a drip fluid channel in a medical institution.

The present inventors have conducted various studies from a comprehensive point of view regarding the points of environment, safety, energy saving, cleaning and sterilization efficiency, and the like, and have obtained the present invention. That is, since this cleaning solution is generated by electrolysis, an alkaline buffer cleaning solution and a hypochlorous acid solution can be simultaneously produced, and washing with an alkaline cleaning solution and deodorization / sterilization with a hypochlorous acid solution are possible.

That is, according to the present invention, there is provided a washer for producing hypochlorite ion having a bleaching action and a disinfecting action for tableware,
In particular, a dishwasher is provided. Inorganic halogen salt in the washer,
For example, by providing an electrolytic cell in a supply device of a sodium chloride solution (saline) and a circulation path of washing water, an electrode for electrolysis is arranged there and decomposed during storage of the detergent,
Hypochlorite ions having a strong bleaching action and a bactericidal action can be generated without adding an oxidizing agent for inactivating the enzyme.

In addition, by electrolysis in the remaining water after the drying step, bacteria generated in the remaining water with the passage of time can be disinfected and organic substances adhering to the piping in the remaining water can be decomposed. It is also possible to provide a typical dishwasher.

In the case of hypochlorous acid, the self-decomposition property (non-residual property) when the hypochlorous acid cleaning solution remains in the food is high,
There is very little concern about ingestion of oral sterilizing components.
In particular, hypochlorite ions not only have strong bactericidal activity, but also exist only in an aqueous solution, and are naturally decomposed and removed in a drying step after washing tableware and food. In addition, even when drying is not performed sufficiently,
Is less than 5, the hypochlorite ion decomposes spontaneously.

The present invention is to swell and dissociate stains on an object to be washed by using an alkaline buffer solution, and to suspend stain components mainly composed of oil components in the solution. The term “buffer solution” as used herein is a general term for an aqueous solution having an effect of changing the temperature and pH from the outside, that is, an effect of mitigating the influence of stains and fungi in the object to be washed. In general, stabilization of pH and the like by a buffer is represented by the following reaction formula.

Considering a mixed solution of weak acid HA and its salt BA,

[0024]

(Equation 1)

## EQU2 ## HA dissociation is

[0026]

(Equation 2)

However, the reaction in which the equilibrium reaction represented by the equation proceeds to the right proceeds only slightly. That is, it is only slightly dissociated. Thus, A in the mixed solution ^- the concentration of the reaction in which BA represented by the formula completely dissociated, B
Determined by the concentration of A. Even if H ⁺ or OH ^- is mixed into such a liquid to some extent, the equilibrium moves to the left and right,
The hydrogen ion concentration does not change apparently. That is, p
H change becomes extremely small.

The calculation of pH is represented by the following equation, where K is the dissociation constant of the equation.

[0029]

(Equation 3)

[0030]

(Equation 4)

More specifically, in a mixed solution of baking soda and sodium hydroxide, sodium hydroxide is completely dissociated.

[0032]

(Equation 5)

However, NaHCO ₃ is slightly dissociated.

[0034]

(Equation 6)

[0035]

(Equation 7)

When such a liquid having an alkaline buffering action is used as the cleaning liquid, the reactivity with the contaminants is maintained in a constant and active state, so that the liquid adheres to the cleaning object placed in the cleaning tank. In addition to being able to effectively remove dirt, the buffer solution is characterized by the effect that even if the alkalinity is affected by the pH change due to dissolution of dirt components in the liquid as the washing proceeds, Can be relaxed, so p
The fluctuation of H is small and the detergency can be maintained. Of course, when a surfactant is added to the washing solution having an alkaline buffering action of the present invention, it has a synergistic detergency due to the buffering action. Further, by adding the anti-redeposition agent, it is possible to prevent the contamination components dissolved and removed from the surface of the object to be cleaned from adhering to the surface of the object to be cleaned, walls in the cleaning tank, and the like.

According to the present invention, a dishwasher is provided with a supply device for saline and an electrode for electrolysis in a circulation path of washing water, and hypochlorite ion having a bleaching action and a disinfecting action for dishes and foods is provided. The main purpose is to provide a dishwasher that produces.

More specifically, in a dishwasher for washing an object to be washed by putting an object to be washed such as tableware into a washing tank and circulating and spraying a washing liquid in the washing tank, the washing machine contains alkali metal ions. A dishwasher or a dishwasher characterized in that a washing solution is generated by applying a voltage to an electrode and applying a voltage to an electrode, and an inorganic halide salt is mixed and dissolved in an aqueous solution containing an alkali metal ion, and the aqueous solution is similarly treated. Dishwasher characterized by producing a washing liquid having a bactericidal property by electrolysis, furthermore, an inorganic halogen salt or an aqueous solution thereof, more specifically, a salt or a saline solution, provided in the dishwasher The cleaning solution containing hypochlorite ion is generated by performing electrolysis during the rinsing step after the main cleaning, and the cleaning is performed by using this solution for rinsing. It is possible dishwasher, characterized in that a sterilizing and washing process.

Furthermore, when hypochlorous acid is used for sterilization, its persistence after drying is extremely small, so that even if it is used for washing food, the possibility of oral ingestion can be reduced, so that safety is extremely high. In addition, for the same reason, it can be used for the production of sterilizing cleaning water for medical instruments.
It can be applied to washing of a drip channel, use for sterilizing hand washing water, or use for base water (acidic water) of lotion.

The method of producing electrolyzed water may or may not use an ion-exchange membrane, but the former is generally preferred for producing a high concentration of hypochlorous acid. Furthermore, in consideration of the function of the ion exchange membrane, one type of cation exchange membrane is used, and two types of cation exchange membrane and anion exchange membrane having different functions are appropriately used to form electrolytic water. Since the function is strengthened, it is possible to further enhance the cleaning ability and the sterilization ability.

As a chlorine source, sodium chloride is typical, but sodium hypochlorite and potassium chloride can also be used.

[0042]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method of preparing a cleaning test sample to which dirt is adhered will be described in detail. The type of tableware to be used for the test shall be a set of tableware that can be accommodated in the dishwasher used for the cleaning test. Common tableware types are
Large plates, medium plates, small plates, teacups and teacups
The surface shall be smooth, plain and white porcelain. The cup is made of colorless and transparent glass. The soup bowl and chopsticks are made of plastic urethane coating, and the fork, spoon and knife are made of stainless steel.

First, the glass cup is soiled by pouring tomato juice in half of the set number and milk in the rest until the 8th minute to remove the contents. Allow to stand for 30 minutes and allow to air dry, and remove the liquid remaining on the bottom by lowering the cup for 5 seconds. Then, leave it for 30 minutes and let it dry naturally.

For the method of soiling the soup bowl, miso soup containing wakame with fresh green onions is put into the soup bowl for 7 minutes, and after 10 minutes, it is confirmed that the miso has settled, and then the supernatant juice is discarded while the miso is left. . At this time, leave about 15 mm square wakame and three pieces of green onion.

For the method of soiling the teacup, use the green tea and put the tea until the 7th minute of the teacup and leave it for 30 minutes. Discard the tea gently, leaving the tea residue on the bottom.

The dish and spoon can be soiled by thoroughly mixing the rice, raw eggs and curry in a suitable vessel, placing a spoonful of the mixture (curry rice) on the platter, and evenly painting the center portion to a diameter of about 5 cm. Then remove the curry rice, leaving 10 rice grains. Leave one grain of rice on each side on the spoon and leave it lying down.

For the method of soiling the middle plate, the frozen tofu cutlet of the frozen food is heated on a microwave oven, placed on the middle plate, covered with a cutlet sauce, and cut into small pieces with a knife and fork. Spread 5cm in diameter at the center of the surface of the dish evenly with tonkatsu oil and tonkatsu sauce.

The knife and fork are contaminated with an oil film of tonkatsu oil.

As for the method of soiling the small dish, a semi-ripened ham egg with a substantially hardened white portion is prepared, and each dish is equally cut using a knife and a fork used for cutting a tonkatsu, and the dish is contaminated with oil from yolk and ham. The ham egg contamination is further adhered to the knife and fork previously contaminated with the oil film of tonkatsu oil.

The rice bowl is contaminated by putting rice and stirring the rice gently with chopsticks, leaving three pieces of rice inside.

The chopsticks are soiled by inserting and removing chopsticks 10 times from the rice in a bowl, and then attaching one grain of rice per chopstick to the tip of the chopsticks to produce contaminants. Subsequently, a method for evaluating the cleaning performance will be described.

A predetermined number of the dishware contaminated as described above are placed on a washing basket 5 arranged in the dishwasher, and a predetermined washing step is performed. After the washing is completed, the remaining state of the contamination is visually evaluated and evaluated. The evaluation method is outlined below.

This method is a visual judgment method in which the cleaning rate is 100% when the contamination of the tableware is completely removed, and 0% when the adhered substance remains. Tableware that is completely returned to
The surface of the tableware, the back side is slightly cloudy, and there is no matte, and the surface of the tableware is free of foreign matter, and there are 5 or less 0.5 mm square or less reattached substances on the back side of the tableware of B judgment,
Other than the above, the tableware of C determination is used, and the cleaning rate is expressed in% by applying the following formula.

[0054]

(Equation 8)

Hereinafter, a method for cleaning, disinfecting, and cleaning a dishwasher equipped with an electrolytic cell will be generally described.

FIG. 2 is a schematic diagram showing an example of an embodiment of a dishwasher according to the present invention. Although not shown, water is supplied to the mixing tank 9 from a water supply source such as tap water in the dishwasher, and a compound containing an alkali metal ion such as sodium hydrogencarbonate, sodium carbonate, hydrogencarbonate is contained therein. One or a mixture of potassium, potassium carbonate, lithium carbonate, sodium tetraborate and the like is charged, and the mixture is stirred and dissolved to form an aqueous solution, and an inorganic halogen salt is further added to prepare a mixed solution. Although a charging and mixing method is not illustrated, various expedients can be applied. The electrolytic solution 10 thus produced is supplied to the electrolytic cell 11. In the case of simplification, the mixing tank 9 and the electrolytic tank 11 may be the same tank. In this case, the operation of supplying the electrolytic solution from the mixing tank 9 to the electrolytic tank 11 can be simplified.

FIG. 3 shows an embodiment of the electrolytic cell. In an electrolytic cell 11, a DC power source 1 is sandwiched between a positive electrode 12 and a negative electrode 13.
The power is supplied by adjusting the current by applying a voltage appropriately controlled by 4 and electrolysis is performed. Thus, the alkaline buffered cleaning water 15 can be generated near the negative electrode 13 and the hypochlorous acid solution 16 can be generated near the positive electrode 12.

Using the two alkaline buffered washing waters 15 and the hypochlorous acid solution 16 prepared in the electrolytic cell 11, a washing pump is provided to the dishes and the like placed in the washing tank 1 provided in the dishwasher. 2 is used to wash and remove dirt attached to tableware and the like. As for the injection of washing water, the alkaline buffered washing water 15 is mainly used for washing dirt, and the hypochlorous acid solution is used as a finishing water for rinsing after washing dirt, thereby utilizing the pasteurizing effect of dishes and the like. it can.

In the method of draining the washing water used for washing, water flowing down from tableware or the like is collected by a water storage tank 19 in FIG. 2 and discharged through a drain port. Also, in general,
The water storage tank 19 is also used as a primary storage location of the cleaning water for circulating the cleaning water.

The electrolytic cell 11 may take several forms other than the form shown in FIG. 3, which are shown in FIGS. FIG. 3 shows an example of an electrolytic cell not separated by an ion-exchange membrane (ion-exchange resin). FIGS. 4 and 5 use an ion-exchange resin membrane, and are roughly classified into these two types. The latter type further includes a type using only one kind of ion exchange resin membrane and a type using two kinds of ion exchange resin membranes, which are shown in FIGS. 4 and 5, respectively. A detailed description will be given in the examples.

Next, general properties of the cleaning solution generated by the electrolysis will be described.

Conventionally, it is said that acidic water has bactericidal activity, but it cannot be determined unconditionally because it differs depending on the type of bacteria to be sterilized.
Is said to be about 3 or less. In the present invention, since the aqueous solution of the inorganic halogen salt is electrolyzed, hypochlorous acid is generated, and washing water having a strong bactericidal action can be obtained. This hypochlorous acid solution is generated on the positive electrode side of the electrolytic cell, and by setting the pH to a substantially neutral region of 8 to 6, decomposition of hypochlorous acid is suppressed, and the life as a cleaning solution is extended, Inactivation due to spontaneous decomposition of hypochlorous acid exhibiting a bactericidal effect can be prevented and can be effectively used for sterilization. Furthermore, since the electrolytic hypochlorous acid solution has a pH buffering action, the pH is hardly changed by washing, and the ability to maintain a pH range in which this sterilizing effect is exhibited is high.

On the other hand, the alkaline buffer can maintain the pH region where the cleaning performance is similarly exhibited by the buffering action even during the cleaning process, so that the cleaning performance is maintained in a high state.

By improving the structure of the electrolytic cell to a structure using an ion exchange resin membrane, the performance of these cleaning liquids is improved because the ions attracted by electrolysis near each electrode are appropriately separated. Further, since the generated cleaning liquids can be separated without being mixed with each other, unexpected changes in pH due to mixing of the cleaning liquids in addition to ion mixing can be prevented.

As the electrode used in the electrolytic cell, a titanium lath plate generally plated with platinum is often used. This is because electrochemical oxidation resistance and reduction resistance are high and the effect of suppressing generation of gas generated during electrolysis (gas generation overvoltage) is high. In addition, a carbon electrode can be used.

Next, a method for evaluating the sterilizing performance of the washing water will be described.

10 ml of washing water electrolytically generated by a predetermined method
Is dispensed into a petri dish in which a predetermined amount of bacteria has been previously applied to a standard sterile medium, immersed for 10 minutes, and the liquid is discarded. The medium after washing is cultured at a predetermined culture temperature and time determined for each bacterial species together with the unwashed medium for comparison, and after the culture,
The number of colonies is counted and compared with the number of colonies in the unwashed medium for comparison (corresponding to the initial viable cell count). The number of colonies decreased by more than one digit and the total number of colonies was 10
If the value is less than or equal to the Petri dish, it is determined that there is an effect.

On the other hand, without disposing an electrolytic tank or a water tank inside the dishwasher, an electrolytic tank or the like is arranged outside the dishwasher.
Electrolyzed water can be supplied as appropriate through a pipe for washing, and the hypochlorous acid solution obtained by this method can be used for washing foods.

In this case, there is a method of placing and cleaning the food in the dishwasher, but it is not always necessary to wash the food in the dishwasher, and the influence of other dirt and the like adhering to the dish is not always required. When considering also, bypass the piping from the electrolytic cell to the cleaning tank,
It is more sanitary to have a structure having a pipe for discharging the cleaning liquid outside the cleaning device. That is, the washing water is taken out of the refrigerator and washed. As a result, the applicability to food cleaning is expanded, and thus, the type of the cleaning object can be cleaned, such as cutting boards, kitchen knives, and even larger objects.

Further, the electrolytic cleaning water can be used for cleaning other than foods, for example, wiping and cleaning window glass for houses, and is particularly effective for decomposing and cleaning dirt.

Hereinafter, the cleaning and sterilizing performance using the cleaning liquid obtained when each electrolytic cell is used will be described with reference to the drawings as examples and comparative examples of the present invention. Since various methods for preparing a cleaning liquid and a cleaning apparatus using the same are conceivable, the electrolysis conditions and the device configuration are not limited to these examples.

<Embodiment 1> In this embodiment, in the above-described cleaning apparatus, cleaning is performed by using an apparatus having an electrolytic tank without using an ion exchange membrane. Here, in particular, a method for producing the cleaning water by performing electrolysis in the electrolytic cell shown in FIG. 3 will be described with reference to the drawings. In the mixing tank 9, potassium bicarbonate is added to water as a compound capable of releasing alkali metal ions in an aqueous solution.
Dissolve at a concentration of g / l. The concentration is preferably adjusted so that the concentration is in the range of approximately 1/10 or more of the saturation concentration from a value near the saturation concentration at room temperature.
30 ml of potassium chloride as an inorganic halogen salt is added to this aqueous solution.
The mixture was mixed and dissolved at a concentration of g / l. It is preferable that the amount of addition is not more than half the concentration of the compound capable of releasing alkali metal ions. The electrolytic solution thus mixed is supplied to the electrolytic cell 11 from the electrolytic solution supply port. Electrolysis is performed in the electrolytic cell 11 using a constant current power supply 14 having a maximum voltage of 12 V, and an alkaline buffer wash water 15 is generated near the negative electrode 13 and a hypochlorous acid solution 16 is generated near the positive electrode 12. here,
The alkaline buffer obtained from the vicinity of the negative electrode is discharged from the cleaning liquid outlet 21 and used as a cleaning liquid. Similarly, the cleaning liquid containing hypochlorous acid formed near the positive electrode is discharged from the cleaning liquid outlet 21 and used as a sterilizing cleaning liquid.

First, washing is performed with an alkaline buffer solution obtained from the vicinity of the negative electrode. Then, after performing a water rinsing step, final cleaning and sterilization are performed with acidic sterilized water formed near the positive electrode. Of course, it is possible to enhance the washing and sterilizing properties of the surface of the tableware by using the rinse water for the tableware and the like. In the case of general tableware, when energy saving is taken into consideration, the tableware is washed at a temperature around room temperature.
The method of using the washing liquid in the washing step is the same as in a conventional dishwasher.

For comparison, the cleaning method, the amount of water used, and the water temperature were the same in Examples and Comparative Examples unless otherwise specified. Specifically, the washing step (10 minutes)-the first rinsing step (1 minute) → the second rinsing step (3 minutes) → the third rinsing step
(3 minutes)-final rinsing step (20 minutes).

Table 1 summarizes the types of water used and the cleaning results in each cleaning / rinsing step together with other test results. First, the fats and oils, proteins, starch, and other sewage attached to the dishes are washed with an alkaline buffer, and then the dishes are sterilized by washing with a hypochlorous acid solution, and the used washing water is mixed. Dishwashers discharged afterwards are also useful in terms of environmental considerations.

The results of the sterilization test of the hypochlorous acid solution prepared by this method are shown in Table 2 together with other test results.

Example 2 In Example 2, cleaning was performed using an electrolytic cell 11 different from that in Example 1. A method for producing an electrolytic cleaning water by electrolysis in the electrolytic cell shown in FIG. 4 will be described with reference to the drawings. The electrolytic cell according to the second embodiment includes the positive electrode 12
Example 2 is different from Example 1 in that a cation exchange resin film 17 is provided between the anode and the negative electrode 13.

An aqueous solution in which sodium chloride is dissolved at a concentration of 15 g / l as an inorganic halide salt is stored in the storage tank near the positive electrode 12, and a compound capable of releasing alkali metal ions is stored in the storage tank near the negative electrode 13. As a dissolved aqueous solution, sodium bicarbonate is injected as an electrolytic solution at a concentration of 50 g / l, and electrolysis is generated in the same manner as in Example 1. The alkaline buffer washing water 15 and the hypochlorous acid solution 16 are used for washing. The concentration of the aqueous solution and the electrolysis conditions are the same as in Example 1. The cleaning results and the sterilization performance test results are shown in Tables 1 and 2, respectively.

Example 3 In Example 3, cleaning was performed using an electrolytic cell 11 different from that in Example 1. The method for producing electrolytic cleaning water by electrolysis in the electrolytic cell shown in FIG. 5 will be described with reference to the drawings. The structure of the cleaning apparatus is the same as that of the first embodiment except that the cleaning apparatus has a structure of an electrolytic cell divided into three sections by an ion exchange membrane. The cleaning results and the sterilization performance test results are shown in Tables 1 and 2, respectively. The electrolytic cell shown in the present embodiment is divided into three parts by a cation exchange resin membrane 17 and an anion exchange resin membrane 18.

An aqueous solution in which sodium chloride as an inorganic halogen salt was dissolved at a concentration of 20 g / l was stored in the storage tank near the positive electrode 12, and an aqueous solution in which a compound capable of releasing alkali metal ions was dissolved was stored in the storage tank near the negative electrode 13. Concentration 40
g / l sodium bicarbonate, and an aqueous solution (a concentration of 100 g / l sodium carbonate and a concentration of 20 g / l sodium chloride) in which a compound capable of releasing alkali metal ions and an inorganic halide are mixed is electrolyzed in an intermediate storage tank. Inject as a liquid to generate wash water. The concentration of the aqueous solution and the electrolysis conditions are the same as in Example 1. The alkaline buffer cleaning solution 15 and the hypochlorous acid solution 16 electrolytically generated in the same manner as in Examples 1 and 2 are used for cleaning.

In general, first, oils and fats, proteins, starch, and other sewage adhering to tableware are washed with alkaline buffered washing water, passed through a rinsing step using water, and then added to the hypochlorous acid solution in the final rinsing step. Wash and sterilize. Further, the final sterilization treatment may be performed by immersion in a hypochlorous acid solution. The difference in performance from the hypochlorous acid solution in Examples 1 and 2 is due to the difference in the concentration of hypochlorous acid contained in the sterilized water.

As described above, the concentration of hypochlorite ions can be promoted when an ion exchange membrane is used. In addition, the buffering action is used in combination, and the washing action and the bactericidal action are pH
, It can be maintained particularly stably in a buffer having a stable pH.

<Example 4> A small amount (0.1 g to 0.3 g) of polyoxyethylene nonylphenyl ether as a nonionic surfactant was added to about 2 liters of the alkaline buffer washing solution obtained in Example 2. In addition, dishwashing was performed in the same manner as in Example 1. The results of the washing are shown in Table 1. As can be seen from Table 1, the cleaning rate was improved especially by adding a small amount of a nonionic surfactant.

<Comparative Example 1> In the case where washing was performed using a standard dishwasher detergent, a special detergent was used in the washing step of Example 1 instead of the electrolytic alkaline buffer solution, and water was used in the final rinsing step. Table 1 shows the results of comparison of the cleaning performance of the case heated at 77 ° C. and sterilized for 2 minutes. Tables 1 and 2 show the results of comparison of sterilization performance.
Shown in

Comparative Example 2 Tables 1 and 2 show the results of cleaning with ion-exchanged water instead of the dedicated detergent water of Comparative Example 1 as cleaning performance and sterilization performance.

Comparative Example 3 Alkaline ionized water of pH 10 produced by electrolysis with a commercially available ionized water generator was used in Example 1.
Used in place of electrolytic alkaline buffer in the washing step of
Tables 1 and 2 show the results of comparing the cleaning performance and the sterilization performance in the case where the final rinsing step also uses normal temperature acidic water of pH 4 produced by electrolysis.

[0087]

[Table 1]

[0088]

[Table 2]

From the above results, as shown in Tables 1 and 2, the cleaning method using the cleaning liquids of Examples 1 to 3 has a difference in the detergency and the sterilization performance as compared with the conventional ones. It was found to be excellent in the point of sterilization performance. Further, it has been found that the detergency is improved by adding a small amount of a surfactant.

[0090]

According to the present invention, since an alkaline buffer solution is generated by electrolysis, the pH exerts a stability against stains by a buffering action, and is maintained at a high alkalinity even during washing of stains, so that the washing power is maintained.

Further, by simultaneously producing the cleaning solution containing hypochlorite ion having a strong oxidative decomposition action and a bactericidal action by electrolysis, the bactericidal performance can be exhibited even in dishwashing without using a detergent. In addition, since the hypochlorite ion is generated in the buffer solution, decomposition due to pH change can be prevented, the effective ion concentration can be stabilized, and the preservability of the sterilizing and cleaning solution can be improved.

Further, since the cleaning is performed in a system without heating, the food residue that has not been discharged due to adhesion or the like in the cleaning device does not spoil at high temperature and the inside of the refrigerator is sterilized by the sterilizing cleaning liquid. It has a deodorizing effect that odors such as odors can be suppressed.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram relating to a dishwasher according to a conventional example of the present invention.

FIG. 2 is a conceptual diagram relating to a dishwasher used in Examples and Comparative Examples of the present invention.

FIG. 3 is a conceptual diagram relating to an electrolytic cell built in a dishwasher used in Embodiment 1 of the present invention.

FIG. 4 is a conceptual diagram relating to an electrolytic cell built in a dishwasher used in Embodiment 2 of the present invention.

FIG. 5 is a conceptual diagram relating to an electrolytic cell built in a dishwasher used in Embodiment 3 of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Cleaning tank 2 ... Cleaning pump 3 ... Filter 4 ... Nozzle 5 ... Tableware basket 6 ... Tableware 7 ... Heater 8 ... Ventilation fan 9 ... Mixing tank DESCRIPTION OF SYMBOLS 10 ... Electrolyte 11 ... Electrolysis tank 12 ... Positive electrode 13 ... Negative electrode 14 ... DC power supply 15 ... Alkaline buffer washing water 16 ... Hypoxychloric acid solution 17 ... Positive Ion exchange resin membrane 18 ... Anion exchange resin membrane 19 ... Water storage tank 20 ... Electrolyte supply port 21 ... Cleaning liquid discharge port

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C11D 17/08 C11D 17/08 C25B 1/16 C25B 1/16 1/26 1/26 C 9/00 D06F 39/02 Z D06F 39/02 C25B 9/00 E (72) Inventor Noritake Sumida 22-22 Nagaikecho, Abeno-ku, Osaka City, Osaka Inside Sharp Corporation (72) Inventor Kazuhiro Enomoto 22-22 Nagaikecho, Abeno-ku, Osaka City, Osaka No. Sharp Corporation F term (reference) 3B082 CC05 3B155 AA01 BA06 CB38 4H003 AC11 BA27 CA16 DA19 EA16 EA19 ED02 FA01 FA03 FA34 4K021 AB01 AB07 BA03 DB05 DB06 DB31 DB36 DC07

Claims (10)

[Claims] 1. A cleaning solution obtained by electrolyzing a mixed solution obtained by adding an inorganic halogen salt to an aqueous solution containing an alkali metal ion. 2. The cleaning solution according to claim 1, wherein the aqueous solution containing the alkali metal ion is sodium carbonate, sodium hydrogen carbonate, potassium carbonate, potassium hydrogen carbonate, or a complex salt thereof. 3. The method according to claim 2, wherein the inorganic halogen salt is sodium chloride,
3. The cleaning solution according to claim 1, wherein the cleaning solution is potassium chloride. 4. The cleaning liquid according to claim 1, wherein a surfactant is added to the cleaning liquid. 5. A cleaning apparatus, comprising: a cleaning liquid generating apparatus provided with an electrolytic tank for charging a mixed solution obtained by adding an inorganic halide salt to an aqueous solution containing an alkali metal ion. 6. The cleaning apparatus according to claim 5, wherein the electrolytic cell has a cleaning liquid generation device, wherein a space between a positive electrode and a negative electrode is divided by an ion exchange membrane. 7. The cleaning device according to claim 6, wherein the ion exchange membrane is a cation exchange membrane. 8. The positive electrode side of the electrolytic cell is a mixed solution obtained by adding an inorganic halogen salt to an aqueous solution containing an alkali metal ion, and the negative electrode side of the electrolytic cell is an aqueous solution containing an alkali metal ion. The cleaning device according to claim 7, wherein 9. An ion exchange membrane that divides between a positive electrode and a negative electrode, and is divided into three by using an anion exchange membrane on the side close to the positive electrode and a cation exchange membrane on the side close to the negative electrode. The cleaning device according to claim 6, wherein the cleaning device is an electrolytic cell. 10. A portion sandwiched between a cation exchange membrane and an anion exchange membrane, wherein the positive electrode side is an inorganic halide salt and the negative electrode side is an aqueous solution containing an alkali metal ion. 10. The cleaning apparatus according to claim 9, wherein the cleaning apparatus is an aqueous solution containing an alkali metal ion and an inorganic halogen salt.