【０００１】
【発明の属する技術分野】
本発明は、次亜塩素酸、次亜塩素酸ナトリウム等を含有し殺菌作用、消毒作用を有するｐＨ３〜７の範囲の酸性〜中性の電解水を製造するための電解水生成装置に関する。
【０００２】
【従来の技術】
次亜塩素酸、次亜塩素酸ナトリウム等を含有し殺菌作用、消毒作用を有する電解水を製造するための電解水生成装置の一形式として、特公平４−４２０７７号公報に示されているように、電解槽内をイオン透過能を有する隔膜にて区画して形成された一対の隔室にそれぞれ電極を配置して陽極室と陰極室とを構成し、これら両電極室に供給される希薄食塩水を両電極間で電解する電解水生成装置がある。当該電解水生成装置においては、陽極室内で次亜塩素酸を含む酸性水が生成されるとともに、陰極室内でアルカリ性水が生成される。
【０００３】
ところで、当該電解水生成装置においては、陽極室側生成水はｐＨが２〜３という強い酸性水となる。次亜塩素酸、次亜塩素酸ナトリウム等を含む水溶液ではｐＨが低い程殺菌力は高く、殺菌力の点からすれば低ｐＨ程好ましいが、処理すべき用途により最適なｐＨは異なる。例えば、野菜類では、水溶液が低ｐＨである場合には褐色に変色し易く、その最適ｐＨは６〜７である。従って、当該電解水生成装置においては、陽極室側生成水のｐＨを調整して酸性〜中性にする手段が採られている。
【０００４】
すなわち、当該電解水生成装置では、陽極室側生成水のｐＨを調整する手段として、酸性である陽極室側生成水と、アルカリ性である陰極室側生成水と、原水とを、規定された量だけ互いに混合する手段が採られている。しかしながら、かかる混合手段を採用するには、これらの陽極室側生成水、陰極室側生成水、および原水を規定量だけ混合するための各制御バルブが必要であるとともに、これらの各水の混合量を正確に制御するための制御装置、および面倒な制御方法が必要となる。
【０００５】
本出願人は、各種の制御バルブ、制御装置、および面倒な制御方法を要することなく、電解時に一方の電極室内にてｐＨ３〜７の酸性〜中性の生成水を生成する電解水生成装置を、特願平７−５０８００号出願にて提案している。
【０００６】
当該電解水生成装置は、電解槽内をイオン透過能を有する隔膜にて区画して形成された一対の隔室のうち、一方の隔室に第１の電極と第２の電極を互いに対向して配置して第１の電極室を構成するとともに、他方の隔室に第３の電極を前記隔膜を挟んで前記第２の電極に対向して配置して第２の電極室を構成してなるもので、第１の電極室の第１の電極と第２の電極間で希薄食塩水の電解を行い、第１の電極室の第２の電極と第２の電極室の第３の電極間で電気透析を同時に行い、第１の電極室で生成した電解水中の陽イオンを第２の電極室へ電気透析により移動させ、第１の電極室の電解水を酸性側へ移行させることにより、第１の電極室の電解水のｐＨを調整するものである。
【０００７】
【発明が解決しようとする課題】
ところで、当該電解水生成装置においては、装置の運転時に各電極室に希薄食塩水中の微量なカムシウムイオン、マグネシウムイオン等に起因して不溶性物質が析出してスケールとして隔膜、各電極等に付着し、電解効率を低下させることになる。
【０００８】
従って、本発明の目的は、当該形式の電解水生成装置において、電解時に発生するスケールを速やかに除去することにあるが、特に、通常の電解時に陽極となる電極に負電圧を印加することがないようにして、負電圧の印加に対して寿命が低いが電解効率が高い焼成電極の使用を可能にするとともに、使用する直流電源を小型化することにある。
【０００９】
【課題を解決するための手段】
本発明は、電解槽内をイオン透過能を有する隔膜にて区画して形成された一対の隔室のうち、一方の隔室に第１の電極と第２の電極を互いに対向して配置して第１の電極室を構成するとともに、他方の隔室に第３の電極を前記隔膜を挟んで前記第２の電極に対向して配置して第２の電極室を構成してなる電解水生成装置であり、前記第１の電極、前記第２の電極および第３の電極を第１の直流電源に接続するとともに、前記第２の電極および前記第３の電極を第２の直流電源に接続し、かつ前記第１の直流電源と前記第１の電極、前記第２の電極および前記第３の電極の接続回路にそれぞれ切換スイッチを介装するとともに、前記第２の直流電源および前記第３の電極の接続回路に開閉スイッチを介装し、前記第１の直流電源を電解専用の電源として前記第１の電極と前記第２の電極間での第１の電解と、前記第２の電極と前記第３の電極間での極性を異にする第２，第３の電解を選択可能に構成とし、かつ前記第２の直流電源を電気透析専用の電源として前記第１の電解時に電気透析を可能に構成したことを特徴とするものである。
【００１０】
本発明に係る電解水生成装置においては、被電解水として希薄食塩水を採用して、同希薄食塩水を前記両電極室に供給する態様を採ることができ、また前記被電解水として希薄食塩水を採用して、同希薄食塩水を前記第１の電極室に供給するとともに、前記第２の電極室には通常の水を供給する態様を採ることができる。
【００１１】
【発明の作用・効果】
このように構成した電解水生成装置においては、第１の電極室の第１の電極と第２の電極間で希薄食塩水等を電解することができ、同時に第１の電極室の第２の電極と第２の電極室の第３の電極間で第１の電極室で生成された電解水を電気透析して、第１の電極室の電解水中の陽イオンを第２の電極室へ移動させ、同電解水を漸次酸性側へ移行することができる。この場合、これら両電極間の電流および／または電圧を調整することにより、第１の電極室で生成される生成水のｐＨを３〜７の範囲に調整することができる。この運転時には、主として第２の電極、隔膜、および第３の電極にスケールが発生する。
【００１２】
また、当該電解水生成装置において、各切換スイッチと開閉スイッチの動作により、第１の電極室の第１の電極を非通電状態にして、第１の電極室の第２の電極と第２の電極室の第３の電極を極性を互いに選択的に切換えて第２の電解と第３の電解を構成することができる。これにより、第２の電極、隔膜、および第３の電極に析出したスケールを除去することができる。この場合、通常の電解時に陽極専用として使用する第１の電極には通電しないため負電圧がかからず、第１の電極として電解効率のよい白金イリジウム系の焼成電極を使用しても、イリジウムの溶出による第１の電極の劣化が抑制され、第１の電極の寿命を向上させることができる。また、第２の電極および第３の電極については、これら両電極間ではスケール除去という短時間の電解しか行わないため、電解効率が低いが耐久性が高くてコストの低い白金鍍金チタン系の電極を採用することができて有利である。
【００１３】
また、当該電解水生成装置においては、電解専用の第１の直流電源と電気透析専用の第２の直流電源を採用して、電解専用の第１の直流電源をスケール除去工程である第２の電解および第３の電解に使用するものであるから、第２の直流電源をスケール除去工程である第２の電解および第３の電解に使用する場合に比較して、第２の直流電源として電気用量が小さくて小型で廉価な電源を採用することができる。
【００１４】
【発明の実施の形態】
以下本発明を図面に基づいて説明するに、図１〜図３には本発明に係る電解水生成装置の一例が概略的に示されている。当該電解水生成装置は、電解槽１１と、隔膜１２と、第１，第２，第３電極１３ａ，１３ｂ，１３ｃを備えている。隔膜１２はイオン透過能を有するもので、電解槽１１の中央部に配設されて電解槽１１内を一対の隔室に区画している。
【００１５】
第１電極１３ａと第２電極１３ｂとは一方の隔室に所定間隔を保持して並列的に配置されて互いに対向し、同隔室を第１電極室１４ａに構成している。また、第３電極１３ｃは他方の隔室にて隔膜１２とは所定間隔を保持して配置されていて、第２電極１３ｂとは隔膜１２を挟んで並列して互いに対し、同隔室を第２電極室１４ｂに構成している。第１電極室１４ａには、希薄食塩水の供給管路１１ａと電解水の流出管路１１ｂが開口し、かつ第２電極室１４ｂには、希薄食塩水の供給管路１１ｃと電解水の流出管路１１ｄが開口している。
【００１６】
第１電極１３ａ、第２電極１３ｂ、および第３電源１３ｃは第１電源１５ａに接続されているとともに、第２電極１３ｂと第３電極１３ｃとは第２電源１５ｂに接続され、かつ第１，第２電源１５ａ，１５ｂは互いに接続されている。これらの電極１３ａ〜１３ｃと両電源１５ａ，１５ｂの接続回路には第１，第２，第３切換スイッチ１６ａ，１６ｂ，１６ｃと、開閉スイッチ１６ｄが介装されている。
【００１７】
当該電解水生成装置においては、各第１，第２，第３切換スイッチ１６ａ，１６ｂ，１６ｃの切換え動作と、開閉スイッチ１６ｄの開閉動作により、図１〜図３に示す３つの態様の接続回路を構成する。
図１に示す第１の接続態様では、開閉スイッチ１６ｄが閉成された状態で各切換スイッチ１６ａ〜１６ｃがａ側接点に接続されていて、第１電極１３ａを第１電源１５ａの正極に、第２電極１３ｂを第１電源１５ａの負極と第２電源１５ｂの正極に、第３電極１３ｃを第２電源１５ｂの負極にそれぞれ接続する接続回路を構成する。
【００１８】
図２に示す第２の接続態様では、開閉スイッチ１６ｄが開成された状態で各切換スイッチ１６ａ〜１６ｃがｂ側接点に接続されていて、第２電極１３ｂを第１電源１５ａの正極に、第３電極１３ｃを第１電源１５ａの負極にそれぞれ接続する接続回路を構成する。この場合には、第１電極１３ａは両電源１５ａ，１５ｂとは接続されていない。
【００１９】
図３に示す第３の接続態様では、開閉スイッチ１６ｄが開成された状態で第１切換スイッチ１６ａがａ側接点に、第２切換スイッチ１６ｂがｂ側接点に、第３切換スイッチ１６ｃがａ側接点に接続されていて、第２電極１３ｂを第１電源１５ａの負極に、第３電極１３ｃを第１電源１５ａの正極にそれぞれ接続する接続回路を構成する。この場合にも、第１電極１３ａは両電源１５ａ，１５ｂとは接続されていない。
【００２０】
なお、図１〜図３において、符号１７ａは水道水を導入するウォータバルブ、符号１７ｂは希薄食塩水の貯溜タンク、符号１７ｃは希薄食塩水の供給ポンプ、符号１７ｄ，１７ｅは流量調整バルブである。
【００２１】
このように構成した電解水生成装置においては、図１の第１の接続態様での運転（通常運転）では第１電極室１４ａで希薄食塩水の電解がなされ、第１電極室１４ａと第２電極室１４ｂ間で電気透析がなされ、図２に示す接続態様での運転（第１スケール除去運転）では第１電極室１４ａの第２電極１３ｂと第２電極室１４ｂの第３電極１３ｃ間で希薄食塩水の電解がなされ、図３に示す接続態様での運転（第２スケール除去運転）では第１電極室１４ａの第２電極１３ｂと第２電極室１４ｂの第３電極１３ｃ間で、第１スケール除去運転とは両電極１３ｂ，１３ｃが逆極性の電解がなされる。図４には、これら３つの運転時における各電極１３ａ〜１３ｃの通電状態と、各切換スイッチ１６ａ〜１６ｃの動作状態を示すタイミングチャートが示されている。
【００２２】
当該電解水生成装置における通常運転時には、第１電極室１４ａの第１電極１３ａと第２電極１３ｂ間で希薄食塩水を電解することができ、同時に第１電極室１４ａの第２電極１３ｂと第２電極室１４ｂの第３電極１３ｃ間で電気透析して第１電極室１４ａで生成された電解水中の陽イオンを第２電極室１４ｂへ移動させることができる。この場合、これら両電極１３ｂ，１３ｃ間に供給する電流および／または電圧を調整することにより第１電極室１４ａで生成された電解水を酸性側へ移行させて、そのｐＨを３〜７の範囲に調整することができる。この運転時には、主として第２電極１３ｂ、隔膜１２、および第３電極１３ｃにスケールが漸次析出する。
【００２３】
また、当該電解水生成装置における第１スケール除去運転においては、第１電極室１４ａの第１電極１３ａが非通電状態になり、第１電極室１４ａの第２電極１３ｂと第２電極室１４ｂの第３電極１３ｃ間で電解がなされる。この場合には、第２電極１３ｂが第１電源１５ａの正極に接続しかつ第３電源１３ｃが同電源１５ａの負極に接続した状態で電解が生じるため、主として第２電極１３ｂおよび隔膜１２側に析出していたスケールが除去され、この電解にともない第３電極１３ｃにはさらにわずかなスケールが析出する。
【００２４】
また、当該電解水生成装置における第２スケール除去運転においては、第１電極室１４ａの第１電極１３ａが非通電状態になり、第１電極室１４ａの第２電極１３ｂと第２電極室１４ｂの第３電極１３ｃ間で電解がなされる。この場合には、第２電極１３ｂが第１電源１５ａの負極に接続しかつ第３電源１３ｃが同電源１５ａの正極に接続した状態で電解が生じるため、主として第３電極１３ｃ側に析出していたスケールが除去される。これにより、電解槽１１の各部位に析出していたスケールをほとんど除去することができる。
【００２５】
このように、当該電解水生成装置においては、スケール除去運転時には、通常運転時に陽極用として使用する第１電極１３ａには通電しないため負電圧が印加されず、第１電極１３ａとして電解効率のよい白金イリジウム系の焼成電極を使用しても、イリジウムの溶出による第１電極１３ａの劣化が抑制され、第１電極１３ａの寿命を向上させることができる。また、第２電極１３ｂおよび第３電極１３ｃについては、これら両電極１３ｂ，１３ｃ間ではスケール除去運転時の電解という、通常運転に比較して極めて短時間の電解しか行わないため、電解効率が低いが耐久性が高くてコストの低い白金鍍金チタン系の電極を採用することができて有利である。
【００２６】
また、当該電解水生成装置においては、第１電源１５ａを電解専用の電源とし、かつ第２電源１５ｂを電気透析専用の電源として、第１電源１５ａを両スケール除去工程での直流電源としても使用するものであるから、第２電源１５ｂを各スケール除去工程の直流電源に使用する場合に比較して、第２電源１５ｂとして電気用量が小さくて小型で廉価な電源を採用することができる。
【００２７】
すなわち、スケール除去運転では、電解電流が大きいほどスケールが除去し易いため、例えば１５Ａ〜３０Ａ程度の大きな電流が必要である。これに対して、通常運転での電気透析では例えば０．５Ｖ程度（電流は数Ａ）の低い電圧で十分である。このため、電気透析用の電源をスケール除去運転の直流電源としても使用する場合には、スケール除去に適した電気容量が大きくて大型で高価な電源が必要である。しかしながら、当該電解水生成装置においては、スケール除去運転の直流電源として通常運転の直流電源である第１電源１４ａを使用するものであるため、第２電源１５ｂは電気透析専用の直流電源でよく、第２電源１５ｂをスケール除去運転の直流電源として使用する場合に比較して、電気用量が小さくて小型で廉価な電源でよい。
【図面の簡単な説明】
【図１】本発明の一例に係る電解水生成装置の通常運転時の状態を示す概略構成図である。
【図２】同電解水生成装置の第１スケール除去運転時の状態を示す概略構成図である。
【図３】同電解水生成装置の第２スケール除去運転時の状態を示す概略構成図である。
【図４】同電解水生成装置における各電極の通電状態と、各切換スイッチの動作状態を示すタイミングチャートである。
【符号の説明】
１１…電解槽、１２…隔膜、１３ａ，１３ｂ，１３ｃ…電極、１４ａ，１４ｂ…電極室、１５ａ，１５ｂ…電源、１６ａ，１６ｂ，１６ｃ…切換スイッチ、１６ｄ…開閉スイッチ。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electrolyzed water generating apparatus for producing acidic to neutral electrolyzed water having a bactericidal action and a disinfecting action in a pH range of 3 to 7, which contains hypochlorous acid, sodium hypochlorite and the like.
[0002]
[Prior art]
As one type of electrolyzed water generating apparatus for producing electrolyzed water containing hypochlorous acid, sodium hypochlorite and the like, which has a bactericidal action and a disinfecting action, it is disclosed in Japanese Patent Publication No. 4-42077. The electrodes are arranged in a pair of compartments formed by partitioning the inside of the electrolytic cell with a membrane having ion permeability, thereby forming an anode compartment and a cathode compartment. There is an electrolyzed water generator for electrolyzing a saline solution between both electrodes. In the electrolyzed water generator, acidic water containing hypochlorous acid is generated in the anode chamber, and alkaline water is generated in the cathode chamber.
[0003]
By the way, in the electrolyzed water generating apparatus, the generated water on the anode chamber side is a strongly acidic water having a pH of 2 to 3. In an aqueous solution containing hypochlorous acid, sodium hypochlorite, or the like, the lower the pH, the higher the bactericidal activity. The lower the pH, the better the bactericidal activity. However, the optimum pH is different depending on the application to be treated. For example, in the case of vegetables, when the aqueous solution has a low pH, the color is easily changed to brown, and the optimum pH is 6 to 7. Therefore, in the electrolyzed water generating apparatus, means for adjusting the pH of the generated water on the anode chamber side to make it acidic to neutral is adopted.
[0004]
That is, in the electrolyzed water generation apparatus, as a means for adjusting the pH of the anode-room-side generated water, acidic anode-room-side generated water, alkaline-cathode-room-side generated water, and raw water are regulated in a specified amount. Only means of mixing with each other are taken. However, in order to employ such mixing means, it is necessary to provide control valves for mixing the generated water on the anode chamber side, the generated water on the cathode chamber side, and the raw water by a specified amount, and to mix these respective waters. A control device for accurately controlling the amount and a complicated control method are required.
[0005]
The present applicant has developed an electrolyzed water generation apparatus that generates acidic to neutral product water having a pH of 3 to 7 in one electrode chamber during electrolysis without requiring various control valves, control devices, and complicated control methods. And Japanese Patent Application No. 7-50800.
[0006]
In the electrolyzed water generation device, a first electrode and a second electrode are opposed to each other in one of a pair of compartments formed by partitioning the inside of an electrolytic cell with a membrane having ion permeability. To form a first electrode chamber, and to arrange a third electrode in the other compartment so as to face the second electrode with the diaphragm interposed therebetween to constitute a second electrode compartment. Electrolyzing a diluted saline solution between the first electrode and the second electrode of the first electrode chamber, and performing the electrolysis of the diluted saline solution between the first electrode chamber and the second electrode of the second electrode chamber. Electrodialysis is performed simultaneously, the cations in the electrolyzed water generated in the first electrode chamber are moved to the second electrode chamber by electrodialysis, and the electrolyzed water in the first electrode chamber is transferred to the acidic side. , For adjusting the pH of the electrolytic water in the first electrode chamber.
[0007]
[Problems to be solved by the invention]
By the way, in the electrolyzed water generating apparatus, during operation of the apparatus, an insoluble substance is precipitated in each electrode chamber due to a small amount of camsium ion, magnesium ion, etc. in the dilute saline and adheres to the diaphragm, each electrode, etc. as a scale. As a result, the electrolysis efficiency is reduced.
[0008]
Therefore, an object of the present invention is to quickly remove scale generated during electrolysis in an electrolyzed water generation apparatus of this type, and in particular, to apply a negative voltage to an electrode serving as an anode during normal electrolysis. Therefore, it is possible to use a fired electrode having a short life but high electrolysis efficiency with respect to application of a negative voltage, and to downsize a DC power supply to be used.
[0009]
[Means for Solving the Problems]
According to the present invention, a first electrode and a second electrode are arranged so as to face each other in one of a pair of compartments formed by partitioning the inside of an electrolytic cell by a membrane having ion permeability. Electrolytic water comprising a first electrode chamber and a third electrode disposed in the other compartment facing the second electrode with the diaphragm interposed therebetween to constitute a second electrode compartment. A generator, wherein the first electrode, the second electrode, and the third electrode are connected to a first DC power supply, and the second electrode and the third electrode are connected to a second DC power supply. And a switch connected to a connection circuit between the first DC power supply and the first electrode, the second electrode, and the third electrode, and the second DC power supply and the second DC power supply. An open / close switch is interposed in the connection circuit of the third electrode, and the first DC power supply is connected to a dedicated power supply for electrolysis. As the first electrolysis between the first electrode and the second electrode, and the second and third electrolysis having different polarities between the second electrode and the third electrode. And wherein the second DC power supply is used as a power supply dedicated to electrodialysis so that electrodialysis can be performed during the first electrolysis.
[0010]
In the electrolyzed water generating apparatus according to the present invention, it is possible to adopt a mode in which a dilute salt solution is adopted as the water to be electrolyzed and the dilute salt solution is supplied to the two electrode chambers. It is possible to adopt a mode in which the diluted saline is supplied to the first electrode chamber by using water, and normal water is supplied to the second electrode chamber.
[0011]
[Action and Effect of the Invention]
In the electrolyzed water generating apparatus configured as described above, dilute saline or the like can be electrolyzed between the first electrode and the second electrode of the first electrode chamber, and at the same time, the second electrode of the first electrode chamber can be electrolyzed. Electrolyzing the electrolyzed water generated in the first electrode chamber between the electrode and the third electrode in the second electrode chamber, and moving cations in the electrolyzed water in the first electrode chamber to the second electrode chamber. As a result, the electrolyzed water can be gradually transferred to the acidic side. In this case, by adjusting the current and / or voltage between these two electrodes, the pH of the generated water generated in the first electrode chamber can be adjusted to a range of 3 to 7. During this operation, scale is generated mainly on the second electrode, the diaphragm, and the third electrode.
[0012]
Further, in the electrolyzed water generating apparatus, the first electrode of the first electrode chamber is de-energized by the operation of each of the changeover switch and the open / close switch, and the second electrode of the first electrode chamber is connected to the second electrode. The second electrolysis and the third electrolysis can be configured by selectively switching the polarity of the third electrode of the electrode chamber with each other. Thereby, the scale deposited on the second electrode, the diaphragm, and the third electrode can be removed. In this case, the first electrode used exclusively for the anode during normal electrolysis is not energized, so that a negative voltage is not applied. Even if a platinum-iridium-based fired electrode having high electrolysis efficiency is used as the first electrode, the iridium can be used. The degradation of the first electrode due to the elution of is suppressed, and the life of the first electrode can be improved. The second electrode and the third electrode are platinum-plated titanium-based electrodes having low electrolysis efficiency but high durability and low cost because only short-time electrolysis of scale removal is performed between these two electrodes. Is advantageous.
[0013]
Further, in the electrolyzed water generating apparatus, a first DC power supply dedicated to electrolysis and a second DC power supply dedicated to electrodialysis are adopted, and the first DC power supply dedicated to electrolysis is used in a second step of removing scale. Since the second DC power supply is used for the electrolysis and the third electrolysis, the second DC power supply is used as the second DC power supply, Smaller, smaller and cheaper power supplies can be employed.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described with reference to the drawings. FIGS. 1 to 3 schematically show an example of an electrolyzed water generating apparatus according to the present invention. The electrolyzed water generating apparatus includes an electrolytic cell 11, a diaphragm 12, and first, second, and third electrodes 13a, 13b, and 13c. The diaphragm 12 has ion permeability, and is disposed at the center of the electrolytic cell 11 to partition the inside of the electrolytic cell 11 into a pair of cells.
[0015]
The first electrode 13a and the second electrode 13b are arranged in parallel in one of the compartments while maintaining a predetermined interval, and face each other, and the compartments are configured as a first electrode compartment 14a. The third electrode 13c is arranged at a predetermined distance from the diaphragm 12 in the other compartment, and is arranged in parallel with the second electrode 13b with the diaphragm 12 interposed therebetween. It is configured as a two-electrode chamber 14b. In the first electrode chamber 14a, a supply line 11a of diluted saline and an outflow line 11b of electrolytic water are opened, and in the second electrode chamber 14b, a supply line 11c of diluted saline and outflow of electrolytic water are formed. The pipe 11d is open.
[0016]
The first electrode 13a, the second electrode 13b, and the third power supply 13c are connected to a first power supply 15a, and the second electrode 13b and the third electrode 13c are connected to a second power supply 15b. The second power supplies 15a and 15b are connected to each other. A first, second and third changeover switches 16a, 16b and 16c and an open / close switch 16d are interposed in a connection circuit between these electrodes 13a to 13c and both power supplies 15a and 15b.
[0017]
In the electrolyzed water generating apparatus, the connection operation in the three modes shown in FIGS. 1 to 3 is performed by the switching operation of each of the first, second, and third changeover switches 16a, 16b, and 16c and the opening and closing operation of the on / off switch 16d. Is composed.
In the first connection mode shown in FIG. 1, each of the changeover switches 16a to 16c is connected to the a-side contact with the open / close switch 16d closed, and the first electrode 13a is connected to the positive electrode of the first power supply 15a. A connection circuit is configured to connect the second electrode 13b to the negative electrode of the first power supply 15a and the positive electrode of the second power supply 15b, and connect the third electrode 13c to the negative electrode of the second power supply 15b.
[0018]
In the second connection mode shown in FIG. 2, each of the changeover switches 16a to 16c is connected to the b-side contact with the open / close switch 16d being opened, and the second electrode 13b is connected to the positive electrode of the first power supply 15a. A connection circuit for connecting the three electrodes 13c to the negative electrode of the first power supply 15a is formed. In this case, the first electrode 13a is not connected to both power supplies 15a and 15b.
[0019]
In the third connection mode shown in FIG. 3, when the open / close switch 16d is opened, the first changeover switch 16a is set to the a-side contact, the second changeover switch 16b is set to the b-side contact, and the third changeover switch 16c is set to the a-side contact. The connection circuit is connected to the contact, and connects the second electrode 13b to the negative electrode of the first power supply 15a and connects the third electrode 13c to the positive electrode of the first power supply 15a. Also in this case, the first electrode 13a is not connected to both power supplies 15a and 15b.
[0020]
1 to 3, reference numeral 17a denotes a water valve for introducing tap water, reference numeral 17b denotes a storage tank for dilute saline, reference numeral 17c denotes a supply pump for dilute saline, and reference numerals 17d and 17e denote flow control valves. .
[0021]
In the electrolyzed water generator configured as described above, in the operation (normal operation) in the first connection mode of FIG. 1, electrolysis of the diluted saline is performed in the first electrode chamber 14a, and the first electrode chamber 14a and the second Electrodialysis is performed between the electrode chambers 14b, and in the operation in the connection mode shown in FIG. 2 (first scale removing operation), between the second electrode 13b of the first electrode chamber 14a and the third electrode 13c of the second electrode chamber 14b. Electrolysis of the diluted saline solution is performed, and in the operation in the connection mode shown in FIG. 3 (second scale removing operation), the second electrode 13b of the first electrode chamber 14a and the third electrode 13c of the second electrode chamber 14b are connected to each other. In the one-scale removal operation, electrolysis with opposite polarities is performed on both electrodes 13b and 13c. FIG. 4 is a timing chart showing the energized state of each of the electrodes 13a to 13c and the operation state of each of the changeover switches 16a to 16c during these three operations.
[0022]
During the normal operation of the electrolyzed water generator, the dilute saline solution can be electrolyzed between the first electrode 13a and the second electrode 13b of the first electrode chamber 14a, and at the same time, the second electrode 13b and the second electrode 13b of the first electrode chamber 14a can be electrolyzed. Electrodialysis between the third electrodes 13c of the two-electrode chamber 14b can move cations in the electrolytic water generated in the first electrode chamber 14a to the second electrode chamber 14b. In this case, by adjusting the current and / or voltage supplied between these two electrodes 13b and 13c, the electrolyzed water generated in the first electrode chamber 14a is shifted to the acidic side, and its pH is in the range of 3 to 7. Can be adjusted. During this operation, scale is gradually deposited mainly on the second electrode 13b, the diaphragm 12, and the third electrode 13c.
[0023]
Further, in the first scale removing operation in the electrolyzed water generating device, the first electrode 13a of the first electrode chamber 14a is in a non-conductive state, and the second electrode 13b and the second electrode chamber 14b of the first electrode chamber 14a are not electrically connected. Electrolysis is performed between the third electrodes 13c. In this case, electrolysis occurs in a state where the second electrode 13b is connected to the positive electrode of the first power supply 15a and the third power supply 13c is connected to the negative electrode of the power supply 15a. The deposited scale is removed, and with this electrolysis, a slightly smaller scale is deposited on the third electrode 13c.
[0024]
Further, in the second scale removing operation in the electrolyzed water generating device, the first electrode 13a of the first electrode chamber 14a is turned off, and the second electrode 13b and the second electrode chamber 14b of the first electrode chamber 14a are turned off. Electrolysis is performed between the third electrodes 13c. In this case, electrolysis occurs in a state where the second electrode 13b is connected to the negative electrode of the first power supply 15a and the third power supply 13c is connected to the positive electrode of the power supply 15a. Therefore, the electrolysis occurs mainly on the third electrode 13c side. Scale is removed. This makes it possible to remove almost all of the scale deposited on each part of the electrolytic cell 11.
[0025]
As described above, in the electrolyzed water generating apparatus, during the scale removing operation, no current is applied to the first electrode 13a used for the anode during the normal operation, so that no negative voltage is applied, and the first electrode 13a has high electrolysis efficiency. Even if a platinum-iridium-based fired electrode is used, deterioration of the first electrode 13a due to elution of iridium can be suppressed, and the life of the first electrode 13a can be improved. Further, the second electrode 13b and the third electrode 13c have a low electrolysis efficiency between the two electrodes 13b and 13c because electrolysis during the scale removing operation is performed only for a very short time as compared with the normal operation. However, it is advantageous that a platinum-plated titanium-based electrode having high durability and low cost can be employed.
[0026]
Further, in the electrolyzed water generating apparatus, the first power supply 15a is used as a power supply dedicated to electrolysis, the second power supply 15b is used as a power supply dedicated to electrodialysis, and the first power supply 15a is also used as a DC power supply in both scale removing processes. Therefore, as compared with a case where the second power supply 15b is used as a DC power supply in each scale removing step, a small-sized and inexpensive power supply having a small amount of electricity can be used as the second power supply 15b.
[0027]
That is, in the scale removing operation, the larger the electrolytic current, the easier the scale is to be removed. Therefore, a large current of, for example, about 15A to 30A is required. On the other hand, in electrodialysis in normal operation, a low voltage of, for example, about 0.5 V (current is several A) is sufficient. For this reason, when the power supply for electrodialysis is also used as a DC power supply for descaling operation, a large, expensive power supply having a large electric capacity suitable for descaling is required. However, in the electrolyzed water generating apparatus, since the first power supply 14a that is the DC power supply for the normal operation is used as the DC power supply for the scale removal operation, the second power supply 15b may be a DC power supply dedicated to electrodialysis. Compared with the case where the second power supply 15b is used as a DC power supply for the scale removing operation, a small-sized and inexpensive power supply with a smaller amount of electricity is sufficient.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing a state during a normal operation of an electrolyzed water generation device according to an example of the present invention.
FIG. 2 is a schematic configuration diagram showing a state during a first scale removal operation of the electrolyzed water generation device.
FIG. 3 is a schematic configuration diagram showing a state at the time of a second scale removing operation of the electrolyzed water generating apparatus.
FIG. 4 is a timing chart showing an energized state of each electrode and an operation state of each changeover switch in the electrolytic water generation device.
[Explanation of symbols]
11 electrolyzer, 12 diaphragm, 13a, 13b, 13c electrode, 14a, 14b electrode chamber, 15a, 15b power supply, 16a, 16b, 16c changeover switch, 16d open / close switch.
