Patent Publication Number: US-2018037480-A1

Title: Method for producing hydrogen water

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field of the Invention 
     The present invention relates to a method of generating hydrogen water. 
     2. Description of the Related Art 
     A hydrogen water generator is known in which an anode electrode plate and a cathode electrode plate are provided inside a container to sandwich a membrane and which is configured to generate hydrogen from the cathode electrode plate by electrolysis of water supplied to the container and generate hydrogen water that contains hydrogen (Patent Document 1: JP2015-223553A). 
     Patent Document 1: JP2015-223553A 
     The above conventional hydrogen water generator can generate alkaline hydrogen water of higher than pH 8 because the hydrogen water is generated such that the water supplied to the cathode chamber is allowed to contain the hydrogen generated from the cathode. In some cases, however, hydrogen water of a neutral range of pH 6 to 8 may be needed other than the alkaline hydrogen water. Unfortunately, the above conventional hydrogen water generator is not able to generate hydrogen water of a neutral range of pH 6 to 8. 
     An object of the present invention is therefore to provide a method of generating hydrogen water of a neutral range of pH 6 to 8 or alkaline hydrogen water of higher than pH 8. 
     SUMMARY OF THE INVENTION 
     According to an aspect of the present invention, the above object is achieved by providing a method of generating hydrogen water of pH 6 to 8 using at least one electrolyzer. The at least one electrolyzer includes a housing, a membrane that partitions an inside of the housing, an anode chamber and a cathode chamber that are formed inside the housing by being partitioned by the membrane, an anode that is provided to be in contact with a surface of the membrane at the anode chamber side, and a cathode that is provided to be in contact with a surface of the membrane at the cathode chamber side. The method includes continuously supplying the cathode chamber with water that contains a mineral component, and 
     1) supplying the anode chamber with water that does not contain a mineral component of which the amount exceeds an impurity content, or 
     2) storing, in the anode chamber, water that contains a mineral component or water that does not contain a mineral component of which the amount exceeds an impurity content. The method further includes applying a DC voltage between the anode and the cathode and delivering hydrogen water generated in the cathode chamber. 
     According to another aspect of the present invention, the above object is achieved by providing a method of generating hydrogen water of pH 6 to 8 using at least one electrolyzer. The at least one electrolyzer includes a housing, a membrane that partitions an inside of the housing from an outside, a cathode chamber that is formed inside the housing by being partitioned by the membrane, an anode that is provided to be in contact with a surface of the membrane located outside the housing, and a cathode that is provided to be in contact with a surface of the membrane at the cathode chamber side. The method includes continuously supplying the cathode chamber with water that contains a mineral component, supplying at least a space between the anode and the membrane with water that does not contain a mineral component of which the amount exceeds an impurity content or water that contains a mineral component, applying a DC voltage between the anode and the cathode, and delivering hydrogen water generated in the cathode chamber. 
     According to still another aspect of the present invention, the above object is achieved by providing a method of generating hydrogen water of higher than pH 8 using at least one electrolyzer. The at least one electrolyzer includes a housing, a membrane that partitions an inside of the housing, an anode chamber and a cathode chamber that are formed inside the housing by being partitioned by the membrane, an anode that is provided to be in contact with a surface of the membrane at the anode chamber side, and a cathode that is provided to be in contact with a surface of the membrane at the cathode chamber side. The method includes continuously supplying the cathode chamber with water that does not contain a mineral component of which the amount exceeds an impurity content or water that contains a mineral component, supplying the anode chamber with water that contains a mineral component, applying a DC voltage between the anode and the cathode, and delivering hydrogen water generated in the cathode chamber. 
     According to yet another aspect of the present invention, the above object is achieved by providing a method of generating hydrogen water using at least one electrolyzer. The at least one electrolyzer includes a housing, a membrane that partitions an inside of the housing, an anode chamber and a cathode chamber that are formed inside the housing by being partitioned by the membrane, an anode that is provided to be in contact with a surface of the membrane at the anode chamber side or provided to be separated from the surface via a small space, and a cathode that is provided to be in contact with a surface of the membrane at the cathode chamber side or provided to be separated from the surface of the membrane at the cathode chamber side via a small space. The method includes continuously supplying the cathode chamber with water that does not contain a mineral component of which the amount exceeds an impurity content or water that contains a mineral component, supplying the anode chamber with water that contains a mineral component, applying a DC voltage between the anode and the cathode, and delivering hydrogen water generated in the cathode chamber. The flow rate of water supplied to the anode chamber is adjusted. 
     According to a further aspect of the present invention, the above object is achieved by providing a method of generating hydrogen water. The method includes preparing at least one electrolyzer. The at least one electrolyzer includes a housing, a membrane that partitions an inside of the housing, an anode chamber and a cathode chamber that are formed inside the housing by being partitioned by the membrane, an anode that is provided to be in contact with a surface of the membrane at the anode chamber side or provided to be separated from the surface via a small space, and a cathode that is provided to be in contact with a surface of the membrane at the cathode chamber side or provided to be separated from the surface of the membrane at the cathode chamber side via a small space. The method further includes supplying the cathode chamber with water of higher than pH 8 generated by electrolysis of water that contains a mineral component, supplying the anode chamber with water generated by electrolysis of water that contains a mineral component, applying a DC voltage between the anode and the cathode, and delivering hydrogen water generated in the cathode chamber. 
     According to the present invention, when water that does not contain a mineral component is supplied to the anode chamber or water that contains a mineral component is stored in the anode chamber, hydrogen water of pH 6 to 8 can be generated in the cathode chamber. Also when water is supplied to a space between the anode and the membrane in an electrolyzer that has only a cathode chamber, hydrogen water of pH 6 to 8 can be generated in the cathode chamber. On the other hand, when water that contains a mineral component is supplied to the anode chamber, hydrogen water of higher than pH 8 can be generated in the cathode chamber. In an embodiment, alkaline hydrogen water can be generated by dissolving a hydrogen-containing gas into water of higher than pH 8. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is an overall schematic view illustrating an embodiment of a hydrogen water generator using the method of generating hydrogen water according to the present invention; 
         FIG. 2A  is an overall schematic view illustrating another embodiment of a hydrogen water generator using the method of generating hydrogen water according to the present invention; 
         FIG. 2B  is an overall schematic view illustrating still another embodiment of a hydrogen water generator using the method of generating hydrogen water according to the present invention; 
         FIG. 3  is an overall schematic view illustrating yet another embodiment of a hydrogen water generator using the method of generating hydrogen water according to the present invention; and 
         FIG. 4  is an overall schematic view illustrating a further embodiment of a hydrogen water generator using the method of generating hydrogen water according to the present invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A method of generating hydrogen water according to the present invention and a hydrogen water generator  1  using the method according to an embodiment will be described hereinafter. The method of generating hydrogen water and the hydrogen water generator  1  can be used to generate hydrogen water and deliver the generated hydrogen water to living organisms, for example, for the purpose of health maintenance, functional maintenance, disease improvement, functional improvement, health check, and/or functional measurement for living organisms (humans and animals) including cells and organs. Examples of delivery means for the generated hydrogen water to living organisms include delivery by way of oral ingestion, delivery by way of injection and infusion, and delivery by way of adding the hydrogen water to a living organism applicable liquid, such as liquid drug and organ storage liquid, which may be applied to a living organism. Note, however, that the intended use of the generated hydrogen water is not limited to the above because, as described above, the present invention is aimed at providing the method of generating hydrogen water and the hydrogen water generator  1  which are able to selectively generate hydrogen water of a neutral range of pH 6 to 8 and alkaline hydrogen water of higher than pH 8. 
     First Embodiment (Method of Generating Neutral Hydrogen Water) 
     The method of generating hydrogen water according to a first embodiment of the present invention is a method of generating hydrogen water of a neutral range of pH6 to 8. Three possible forms is of this method can be considered: 
     (1) a method of generating hydrogen water of a neutral range of pH 6 to 8 using at least one electrolyzer  2 , the at least one electrolyzer  2  comprising: a housing  20 ; a membrane  25  that partitions an inside of the housing  20 ; an anode chamber  21  and a cathode chamber  22  that are formed inside the housing  20  by being partitioned by the membrane  25 ; an anode  23  that is provided to be in contact with a surface of the membrane  25  at the anode chamber  22  side or provided to be separated from the surface via a small space; and a cathode  24  that is provided to be in contact with a surface of the membrane  25  at the cathode chamber  22  side or provided to be separated from the surface of the membrane  25  at the cathode chamber  22  side via a small space, the method comprising: continuously supplying the cathode chamber  22  with water that contains a mineral component; supplying the anode chamber  21  with water that does not contain a mineral component of which the amount exceeds an impurity content; applying a DC voltage between the anode  23  and the cathode  24 ; and delivering hydrogen water generated in the cathode chamber  22 ; 
     (2) a method of generating hydrogen water of a neutral range of pH 6 to 8 using at least one electrolyzer  2 , the at least one electrolyzer  2  comprising: a housing  20 ; a membrane  25  that partitions an inside of the housing  20 ; an anode chamber  21  and a cathode chamber  22  that are formed inside the housing  20  by being partitioned by the membrane  25 ; an anode  23  that is provided to be in contact with a surface of the membrane  25  at the anode chamber  21  side or provided to be separated from the surface via a small space; and a cathode  24  that is provided to be in contact with a surface of the membrane  25  at the cathode chamber  22  side or provided to be separated from the surface of the membrane  25  at the cathode chamber  22  side via a small space, the method comprising: continuously supplying the cathode chamber  22  with water that contains a mineral component; storing, in the anode chamber  21 , water that contains a mineral component; applying a DC voltage between the anode  23  and the cathode  24 ; and delivering hydrogen water generated in the cathode chamber  22 ; and 
     (3) a method of generating hydrogen water of a neutral range of pH 6 to 8 using at least one electrolyzer  2 , the at least one electrolyzer  2  comprising: a housing  20 ; a membrane  25  that partitions an inside of the housing  20  from an outside; a cathode chamber  22  that is formed inside the housing  20  by being partitioned by the membrane  25 ; an anode  23  that is provided to be in contact with a surface of the membrane  25  located outside the housing  20  or provided to be separated from the surface via a small space; and a cathode  24  that is provided to be in contact with a surface of the membrane  25  at the cathode chamber  22  side or provided to be separated from the surface of the membrane  25  at the cathode chamber  22  side via a small space, the method comprising: continuously supplying the cathode chamber  22  with water that contains a mineral component; supplying at least a space between the anode  23  and the membrane  25  with water that does not contain a mineral component of which the amount exceeds an impurity content or water that contains a mineral component; applying a DC voltage between the anode  23  and the cathode  24 ; and delivering hydrogen water generated in the cathode chamber  22 . 
     Reference numerals in the above (1) to (3) correspond to those denoted for hydrogen water generators illustrated in  FIG. 1  to  FIG. 3 . The term “neutral” refers generally to a liquid of pH≈7, but the “neutral range” as used in the present description and claims refers to a range of pH 6 to 8 which includes the neutral pH (≈7). 
     Second Embodiment (Method of Generating Alkaline Hydrogen Water) 
     The method of generating hydrogen water according to a second embodiment of the present invention is a method of generating alkaline hydrogen water of higher than pH 8. Two possible forms of this method can be considered: 
     (1) a method of generating alkaline hydrogen water of higher than pH 8 using at least one electrolyzer  2 , the at least one electrolyzer  2  comprising: a housing  20 ; a membrane  25  that partitions an inside of the housing  20 ; an anode chamber  21  and a cathode chamber  22  that are formed inside the housing  20  by being partitioned by the membrane  25 ; an anode  23  that is provided to be in contact with a surface of the membrane  25  at the anode chamber  21  side or provided to be separated from the surface via a small space; and a cathode  24  that is provided to be in contact with a surface of the membrane  25  at the cathode chamber  22  side or provided to be separated from the surface of the membrane  25  at the cathode chamber  22  side via a small space, the method comprising: continuously supplying the cathode chamber  22  with water that contains a mineral component; supplying the anode chamber  21  with water that contains a mineral component; applying a DC voltage between the anode  23  and the cathode  24 ; and delivering hydrogen water generated in the cathode chamber  22 ; and 
     (2) a method of dissolving a hydrogen-containing gas into alkaline water of higher than pH 8. 
     Reference numerals in the above (1) and (2) correspond to those denoted for hydrogen water generators illustrated in  FIG. 1  to  FIG. 3 . The term “alkaline” refers generally to a liquid of pH&gt;7, but the “alkaline hydrogen water” as used in the present description and claims refers to alkaline hydrogen water of higher than pH 8. In particular, alkaline hydrogen water of pH 9.2 to 9.8 is preferred. 
     &lt;&lt;Example of Hydrogen Water Generator Using Method of Generating Hydrogen Water&gt;&gt; 
     An example of a hydrogen water generator will be described which uses the above-described method of generating neutral hydrogen water according to the first embodiment and method of generating alkaline hydrogen water according to the second embodiment. It is to be noted that the method of generating hydrogen water of the present invention is not limited to only being realized using the hydrogen water generator described below. 
       FIG. 1  is an overall schematic view illustrating an example of the hydrogen water generator  1  using the method of generating hydrogen water according to the present invention. The hydrogen water generator  1  of this example comprises an electrolyzer  2 , an electric power source  3  that applies a DC voltage between a pair of anode  23  and cathode  24  provided in the electrolyzer  2 , a first supply system  4  that continuously supplies a cathode chamber  22  in the electrolyzer  2  with water that contains a mineral component or water that does not contain a mineral component of which the amount exceeds an impurity content, a water delivery system  5  that delivers the hydrogen water generated in the cathode chamber  22 , a second supply system  6  that supplies an anode chamber  21  in the electrolyzer  2  with water that does not contain a mineral component of which the amount exceeds an impurity content, a third supply system  7  that supplies the anode chamber  21  with water that contains a mineral component, and a switch  8  that switches the water supply system to the anode chamber  21  at least between the second supply system  6  and the third supply system  7 . 
     The electrolyzer  2  is configured to include a housing  20 , the anode chamber  21  which is formed in the housing  20  and into which water for electrolysis Wa is introduced, the cathode chamber  22  which is provided separately from the anode chamber  21  in the housing  20  and into which water for electrolysis Wc is introduced, a membrane  25  (also referred to as a “cation exchange membrane,” hereinafter) provided between the anode chamber  21  and the cathode chamber  22  in the housing  20 , the anode  23  provided in the anode chamber  21 , and the cathode  24  provided in the cathode chamber  22 . The housing  20  may be formed of an electrically insulating material, such as plastic, and configured such that the sealing state for water and gas can be maintained except an inlet  211  and outlet  212  for the water for electrolysis Wa and an inlet  221  and outlet  222  for the water for electrolysis Wc, which will be described later. 
     The inside of the housing  20  is partitioned by the cation exchange membrane  25  into the anode chamber  21  and the cathode chamber  22 . In the present embodiment, each of the pair of anode  23  and cathode  24  is formed in a flat plate-like shape and provided to be in contact with a surface of the cation exchange membrane  25  or provided to be separated from the surface via a small space. As used herein, the “small space” refers to a space that is formed to such an extent that a water film can be formed between the anode  23  or cathode  24  and the cation exchange membrane  25 . The anode  23  provided in the anode chamber  21  into which the water for electrolysis Wa is introduced is connected to the positive terminal (+) of the DC electric power source, and the cathode  24  provided in the cathode chamber  22  is connected to the negative terminal (−) of the DC electric power source. 
     The cation exchange membrane  25  of the present embodiment is a cation exchange membrane that is permeable to hydrogen ions and mineral component ions but impermeable to hydroxy ions. In consideration of necessary properties, such as the ion conductivity, physical strength, gas barrier property, chemical stability, electrochemical stability and thermal stability, there may preferably be used an all fluorine-based sulfonic acid membrane that comprises sulfonic groups as the electrolyte groups. Examples of such a membrane include a membrane of Nafion (registered trademark, a DuPont product) which is a copolymer membrane of tetrafluoroethylene and perfluorovinyl ether having a sulfonic group, a membrane of Flemion (registered trademark, available from ASAHI GLASS CO., LTD.), and a membrane of Aciplex (registered trademark, available from Asahi Kasei Corporation). 
     The pair of anode  23  and cathode  24  used in the present embodiment may be those using titanium plates as base materials which are each plated with one or more layers of noble metal selected from the group of platinum, iridium, palladium and the like. However, the present invention is not limited to using such electrode plates, and solid stainless steel plates may also be used without plating. As described above, the anode  23  provided in the anode chamber  21  and the cathode  24  provided in the cathode chamber  22  may not necessarily be pressed and fixed to the cation exchange membrane  25  and may have a small space with the cation exchange membrane  25  to such an extent that a water film is formed therein. 
     The electric power source  3  is configured to include a plug  31  that is connected to a commercial AC power source or the like, and an AC/DC converter  32  that converts the commercial AC current to a DC current. Alternatively or additionally, a DC power source such as a primary or secondary battery may be used as substitute for or in addition to the plug  31  and the AC/DC converter  32  in order to provide a portable hydrogen water generator  1  (i.e. a hydrogen water generator  1  that can be carried anywhere). 
     The housing  20  of the electrolyzer  2  includes the inlet  211  provided at the lower part of the anode chamber  21  for the water for electrolysis Wa, the outlet  212  provided at the upper part of the anode chamber  21  for the water for electrolysis Wa, the inlet  221  provided at the lower part of the cathode chamber  22  for the water for electrolysis Wc, and the outlet  222  provided at the upper part of the cathode chamber  22  for the water for electrolysis Wc. The inlet  221  of the cathode chamber  22  is connected to the first supply system  4  which continuously supplies the cathode chamber  22  in the electrolyzer  2  with water that contains a mineral component, and the outlet  222  of the cathode chamber  22  is connected to the water delivery system  5  which delivers the hydrogen water generated in the cathode chamber  22 . 
     The first supply system  4  includes a tap water source  41  such as a water tap, pipework  42 , and an opening/closing valve  43 . When the valve  43  is opened, the first supply system  4  continuously supplies the tap water, which contains a mineral component, to the cathode chamber  22 . Although not illustrated, when the cathode chamber  22  is supplied with water that is substantially free from a mineral component, a softening apparatus or deionizer may be provided, for example, upstream or downstream the valve  43 . The softening apparatus or deionizer has an ion-exchange resin or reverse osmosis membrane that removes mineral components contained in the tap water. The water delivery system  5  includes pipework  51 , a dissolution part  52 , a flow rate regulating valve  53 , and a water delivery outlet  54 . When the flow rate regulating valve  53  is opened, the water delivery system  5  delivers the hydrogen water as desired. The dissolution part  52  is a tubular body having a larger inner diameter than the inner diameter of the pipework  51  and includes a mixing body, such as a membrane filter, which has fine pores and is provided inside the dissolution part  52 . When the gas-liquid mixture of water and the hydrogen gas generated from the cathode chamber  22  passes through the fine pores of the mixing body, such as a membrane filter, the hydrogen gas becomes fine bubbles thereby to increase the contact surface area with the water. Moreover, the hydrogen gas of fine bubbles and the water are pressurized by the pressurizing force of the tap water source  41  and the opening degree of the flow rate regulating valve  53 , and the hydrogen concentration can therefore be increased. The hydrogen water of a high concentration thus obtained is supplied from the water delivery outlet  54  to a desired site. In an alternative embodiment, the dissolution part  52  may be omitted as necessary. 
     The second supply system  6  includes a tank  61 , pipework  62 , and a pump  63 . The tank  61  stores water that does not contain a mineral component of which the amount exceeds an impurity content. The pipework  62  has an end connected to the switch  8  which is a three-way valve. In contrast, the third supply system  7  comprises pipework  71  that is branched from the pipework  42  of the first supply system  4 . The pipework  71  has an end connected to the switch  8  which is a three-way valve. The switch  8 , which is a three-way valve, switches the water supply system to the anode chamber  21  at least between the second supply system  6  and the third supply system  7 . That is, the switch  8  switches between a position at which the inlet  211  of the anode chamber  21  is supplied with the water which is stored in the tank  61  and is substantially free from a mineral component and a position at which the inlet  211  of the anode chamber  21  is supplied with the water which is from the tap water source  41  and contains a mineral component. In the example illustrated in  FIG. 1 , the third supply system  7  is configured to share the first supply system  4 , but may also be configured to be independent of the first supply system  4  by providing another tap water source separate from the tap water source  41  of the first supply system  4 . In an alternative embodiment, instead of using tap water, a tank may be used to store water that contains a mineral component and the stored water may be supplied from the tank to the anode chamber  21 . In an embodiment, the anode chamber  21  may be manually supplied with water that contains a mineral component or water that is substantially free from a mineral component. In the method of generating hydrogen water according to the present invention, a first mode refers to a mode in which the anode chamber  21  is supplied with water that does not contain a mineral component of which the amount exceeds an impurity content, and a second mode refers to a mode in which the anode chamber  21  is supplied with water that contains a mineral component. To realize the first and second modes and to switch between them, the second supply system  6 , the third supply system  7 , and the switch  8  may be used, or otherwise an operator may manually perform the operation without providing the second supply system  6 , the third supply system  7 , and the switch  8 . 
     The water for electrolysis Wa, Wc used in the hydrogen water generator  1  of the present embodiment is water from which hydrogen gas can be generated at the cathode  24  owing to an electrolysis reaction of the water. Examples of water that contains a mineral component (such as zinc, potassium, calcium, chromium, selenium, iron, copper, sodium, magnesium, manganese, molybdenum, iodine, and phosphorus) typically include tap water and clean water. Examples of water that does not contain a mineral component of which the amount exceeds an impurity content (also referred to as “water that is substantially free from a mineral component,” herein) include purified water, ion-exchanged water, RO water, distilled water, and deionized water. 
     A drain system  9  is connected to the outlet  212  of the anode chamber  21 . The drain system  9  includes pipework  91  and an opening/closing valve  92 . The valve  92  can be opened to discharge the water for electrolysis Wa from the anode chamber  21  when the anode chamber  21  is supplied with water that contains a mineral component after performing the electrolysis while supplying the anode chamber  21  with water that is substantially free from a mineral component, or when the anode chamber  21  is supplied with water that is substantially free from a mineral component after performing the electrolysis while supplying the anode chamber  21  with water that contains a mineral component. The valve  92  can also be opened to discharge the water for electrolysis Wa from the anode chamber  21  in the middle of the electrolysis in which the anode chamber  21  is supplied with water that contains a mineral component. When water that contains a mineral component is stored in the anode chamber  21 , the switch  8  may be closed to stop the water supply from the tap water source  41 . 
     Actions will then be described. 
     When the switch  8  is set at a position of supplying the water from the tap water source  41  which contains a mineral component so that both the anode chamber  21  and cathode chamber  22  of the hydrogen water generator  1  are supplied with the water which contains a mineral component, and a DC voltage is applied between the anode  23  and the cathode  24 , the following reactions occur at the anode  23  and the cathode  24 . 
       Anode: 2OH − →H 2 O+O 2 /2+2 e   − (or H 2 O−2 e   − →2H + +O 2 /2)
 
       Cathode: 2H 2 O+2 e   − →H 2 +2OH −   [Formulae 1]
 
     Here, in the cathode chamber  22 , in addition to the mineral component contained in the water supplied to the cathode chamber  22 , the mineral component supplied to the anode chamber  21  passes through the cation exchange membrane  25  and moves into the cathode chamber  22 . At the same time, hydrogen ions in the anode chamber  21  also pass through the cation exchange membrane  25  and move into the cathode chamber  22 . Then, in the cathode chamber  22 , hydroxy ions OH −  and ions of the mineral component (such as calcium ions Ca 2+  and magnesium ions Mg 2+ ) are ionically combined to generate a compound, such as Ca(OH) 2  and Mg(OH) 2 , which exhibits alkalinity. During this reaction, hydrogen ions H + , which have moved from the anode chamber  21  to the cathode chamber  22 , and hydroxy ions OH −  are combined to be water, but the delivered water from the cathode chamber  22  exhibits alkalinity because the hydrogen-ion concentration is lower than the ion concentration of the mineral component. This applies to the case in which the anode chamber  21  is supplied with water that contains a mineral component and the cathode chamber  22  is supplied with water that is substantially free from a mineral component. That is, in the cathode chamber  22 , the water supplied to the cathode chamber  22  is free from a mineral component, but the mineral component supplied to the anode chamber  21  passes through the cation exchange membrane  25  and moves into the cathode chamber  22 . Then, in the cathode chamber  22 , hydroxy ions OH −  and ions of the mineral component (such as calcium ions Ca 2+  and magnesium ions Mg 2+ ) are ionically combined to generate a compound, such as Ca(OH) 2  and Mg(OH) 2 , which exhibits alkalinity. During this reaction, hydrogen ions H + , which have moved from the anode chamber  21  to the cathode chamber  22 , and hydroxy ions OH −  are combined to be water, but the delivered water from the cathode chamber  22  exhibits alkalinity because the hydrogen-ion concentration is lower than the ion concentration of the mineral component. 
     In contrast, when the switch  8  is set at a position of supplying the water stored in the tank  61  which is substantially free from a mineral component so that the cathode chamber  22  of the hydrogen water generator  1  is supplied with the water which contains a mineral component while the anode chamber  21  is supplied with the water which is substantially free from a mineral component, and a DC voltage is applied between the anode  23  and the cathode  24 , the above reactions occur at the anode  23  and the cathode  24 . Here, in the cathode chamber  22 , the mineral component (such as calcium ions Ca 2+  and magnesium ions Mg 2+ ) contained in the water supplied to the cathode chamber  22  and hydroxy ions OH −  are ionically combined to generate a compound, such as Ca(OH) 2  and Mg(OH) 2 , which exhibits alkalinity. However, at the same time, hydrogen ions in the anode chamber  21  pass through the cation exchange membrane  25  and move into the cathode chamber  22 . Then, in the cathode chamber  22 , hydrogen ions H + , which have moved from the anode chamber  21  to the cathode chamber  22 , and hydroxy ions OH −  are combined to be water. Due to this reaction, the delivered water from the cathode chamber  22  comes close to neutrality from alkalinity. This applies to the case in which the anode chamber  21  is supplied with water that contains a mineral component and the cathode chamber  22  is supplied with water that is substantially free from a mineral component. That is, a compound, such as Ca(OH) 2  and Mg(OH) 2 , which exhibits alkalinity is not generated because the water supplied to the cathode chamber  22  does not contain a mineral component. In addition, hydrogen ions H + , which have moved from the anode chamber  21  to the cathode chamber  22 , and hydroxy ions OH −  are combined to be water. The delivered water from the cathode chamber  22  therefore exhibits neutrality. 
     In an embodiment, the switch  8  is set at a position of supplying the water from the tap water source  41  which contains a mineral component so that both the anode chamber  21  and cathode chamber  22  of the hydrogen water generator  1  are supplied with the water which contains a mineral component, but the switch  8  is then closed to stop the water supply from the tap water source  41  and store the water which contains a mineral component in the anode chamber  21  (i.e., water is not supplied). Then, when a DC voltage is applied between the anode  23  and the cathode  24 , the above reactions occur at the anode  23  and the cathode  24 . 
     Here, in the initial stage of the cathode chamber  22 , in addition to the mineral component contained in the water supplied to the cathode chamber  22 , the mineral component supplied to the anode chamber  21  passes through the cation exchange membrane  25  and moves into the cathode chamber  22 . At the same time, hydrogen ions in the anode chamber  21  also pass through the cation exchange membrane  25  and move into the cathode chamber  22 . Then, in the cathode chamber  22 , hydroxy ions OH −  and ions of the mineral component (such as calcium ions Ca 2+  and magnesium ions Mg 2+ ) are ionically combined to generate a compound, such as Ca(OH) 2  and Mg(OH) 2 , which exhibits alkalinity. During this reaction, hydrogen ions H + , which have moved from the anode chamber  21  to the cathode chamber  22 , and hydroxy ions OH −  are combined to be water, but the delivered water from the cathode chamber  22  exhibits alkalinity because the hydrogen-ion concentration is lower than the ion concentration of the mineral component. 
     However, the mineral component contained in the water stored in the anode chamber  21  decreases with time and finally becomes zero. As time passes, therefore, the situation becomes the same as the case in which the anode chamber  21  is supplied with water that is substantially free from a mineral component, and the delivered water from the cathode chamber  22  exhibits neutrality. Due to a similar action, when the flow rate of water supplied to the anode chamber  21  which contains a mineral component is reduced, the delivered water from the cathode chamber  22  exhibits neutrality as in the case of storing water that contains a mineral component in the anode chamber  21 . 
       FIG. 2A  is an overall schematic view illustrating another embodiment of a hydrogen water generator using the method of generating hydrogen water according to the present invention. The hydrogen water generator  1  illustrated in  FIG. 2A  is configured such that two electrolyzers  2  are connected in series, and other configuration is the same as that of the embodiment illustrated in  FIG. 1 , so the description will be borrowed herein.  FIG. 2B  is an overall schematic view illustrating still another embodiment of a hydrogen water generator using the method of generating hydrogen water according to the present invention. The hydrogen water generator  1  illustrated in  FIG. 2B  is also configured such that two electrolyzers  2  are connected in series, but is different from the embodiment illustrated in  FIG. 2A  in that the electrolyzer  2  of the first stage is another type of electrolyzer in which the anode  23  and the cathode  24  are not in contact with the cation exchange membrane  25 . Water generated in the cathode chamber  22  of such an electrolyzer  2  of the first stage exhibits alkarility while water generated in the anode chamber  21  exhibits acidity, but alkaline water may be supplied to the cathode chamber  22  of the electrolyzer  2  of the second stage thereby to enable delivery of alkaline hydrogen water. 
       FIG. 3  is an overall schematic view illustrating yet another embodiment of a hydrogen water generator using the method of generating hydrogen water according to the present invention. The hydrogen water generator  1  of this example comprises an electrolyzer  2 , an electric power source  3  that applies a DC voltage between a pair of anode  23  and cathode  24  provided outside and inside the electrolyzer  2 , a first supply system  4  that continuously supplies a cathode chamber  22  in the electrolyzer  2  with water that contains a mineral component or water that does not contain a mineral component of which the amount exceeds an impurity content, a water delivery system  5  that delivers the hydrogen water generated in the cathode chamber  22 , and a second supply system  6  that supplies a space between the anode  23  provided outside the electrolyzer  2  and the membrane  25  with water that contains a mineral component or water that does not contain a mineral component of which the amount exceeds an impurity content. 
     The electrolyzer  2  is configured to include a housing  20 , the cathode chamber  22  which is formed in the housing  20  and into which water for electrolysis Wc is introduced, a membrane  25  (also referred to as a “cation exchange membrane,” hereinafter) that partitions the inside of the housing  20  from the outside, the anode  23  provided outside the housing  20 , and the cathode  24  provided in the cathode chamber  22  which is the inside of the housing  20 . The housing  20  may be formed of an electrically insulating material, such as plastic, and configured such that the sealing state for water and gas can be maintained except an inlet  221  and outlet  222  for the water for electrolysis Wc. The electrolyzer  2  is basically the same as those illustrated in  FIG. 1  and  FIG. 2  except that the anode chamber  21  is omitted. 
     The first supply system  4  includes a tap water source  41  such as a water tap, pipework  42 , and an opening/closing valve  43 . When the valve  43  is opened, the first supply system  4  continuously supplies the tap water, which contains a mineral component, to the cathode chamber  22 . Although not illustrated, when the cathode chamber  22  is supplied with water that is substantially free from a mineral component, a softening apparatus or deionizer may be provided, for example, upstream or downstream the valve  43 . The softening apparatus or deionizer has an ion-exchange resin or reverse osmosis membrane that removes mineral components contained in the tap water. The water delivery system  5  includes pipework  51 , a dissolution part  52 , a flow rate regulating valve  53 , and a water delivery outlet  54 . When the flow rate regulating valve  53  is opened, the water delivery system  5  delivers the hydrogen water as desired. The dissolution part  52  is a tubular body having a larger inner diameter than the inner diameter of the pipework  51  and includes a mixing body, such as a membrane filter, which has fine pores and is provided inside the dissolution part  52 . When the gas-liquid mixture of water and the hydrogen gas generated from the cathode chamber  22  passes through the fine pores of the mixing body, such as a membrane filter, the hydrogen gas becomes fine bubbles thereby to increase the contact surface area with the water. Moreover, the hydrogen gas of fine bubbles and the water are pressurized by the pressurizing force of the tap water source  41  and the opening degree of the flow rate regulating valve  53 , and the hydrogen concentration can therefore be increased. The hydrogen water of a high concentration thus obtained is supplied from the water delivery outlet  54  to a desired site. In an alternative embodiment, the dissolution part  52  may be omitted as necessary. 
     The second supply system  6  includes a tank  61 , pipework  62 , and a pump  63 . The tank  61  stores either of water that contains a mineral component or water that does not contain a mineral component of which the amount exceeds an impurity content. The pipework  62  has an end provided toward a space between the anode  23  and the cation exchange membrane  25 . The end of the pipework  62  continuously or intermittently supplies such water to the space between the anode  23  and the cation exchange membrane  25 . In an embodiment, the space between the anode  23  and the cation exchange membrane  25  may be manually supplied with water that contains a mineral component or water that is substantially free from a mineral component. 
     Actions will then be described. 
     When the cathode chamber  22  of the hydrogen water generator  1  is supplied with the water which contains a mineral component while the space between the anode  23  and the cation exchange membrane  25  is supplied with the water which contains a mineral component or the water which is substantially free from a mineral component, and a DC voltage is applied between the anode  23  and the cathode  24 , the above reactions occur at the anode  23  and the cathode  24 . Here, in the cathode chamber  22 , the mineral component (such as calcium ions Ca 2+  and magnesium ions Mg 2+ ) contained in the water supplied to the cathode chamber  22  and hydroxy ions OH −  are ionically combined to generate a compound, such as Ca(OH) 2  and Mg(OH) 2 , which exhibits alkalinity. However, at the same time, hydrogen ions contained in the water supplied to the space between the anode  23  and the cation exchange membrane  25  pass through the cation exchange membrane  25  and move into the cathode chamber  22 . Then, in the cathode chamber  22 , hydrogen ions H + , which have moved from that space to the cathode chamber  22 , and hydroxy ions OH −  are combined to be water. Due to this reaction, the delivered water from the cathode chamber  22  comes close to neutrality from alkalinity. This applies to the case in which the space between the anode  23  and the cation exchange membrane  25  is supplied with water that contains a mineral component and the case in which the space between the anode  23  and the cation exchange membrane  25  is supplied with water that is substantially free from a mineral component. This is because, even when the space between the anode  23  and the cation exchange membrane  25  is supplied with water that contains a mineral component, its content is very small and decreases with time. 
       FIG. 4  is an overall schematic view illustrating a further embodiment of a hydrogen water generator using the method of generating hydrogen water according to the present invention. The hydrogen water generator  1  of this example uses a method of generating alkaline hydrogen water by dissolving a hydrogen-containing gas into alkaline water. The alkaline hydrogen water generator  1  of this example uses an electrolysis water generator  50  as the supply source of alkaline water. The electrolysis water generator  50  comprises an electrolyzer  501 , a membrane  502 , a pair of anode plate  503  and cathode plate  504  that sandwich the membrane  502 , a DC electric power source  505  that supplies a DC voltage between the anode plate  503  and the cathode plate  504 , and water for electrolysis W that is stored in the electrolyzer  501 . A liquid supply pipe  506  for the alkaline water is provided with a degassing module  507  and a vacuum pump  508 , which are used to degass the gas contained in the alkaline water. 
     A hydrogen supply source  510  is provided to supply gas that contains a hydrogen component as the main component (also referred to as a “hydrogen-containing gas,” herein). Examples of the hydrogen supply source  510  include a hydrogen gas cylinder, hydrogen storing alloy, fuel reformer, and electrolysis water generator. The hydrogen-containing gas supplied from such a hydrogen supply source  510  is sent to a junction part  514  via a hydrogen supply pipe  513 . The hydrogen supply pipe  513  is provided with a check valve  511 , and the hydrogen-containing gas having passed through the check valve  511  does not return to the hydrogen supply source  510 . In addition, to regulate the supply pressure of the hydrogen-containing gas from the hydrogen supply source  510  to the junction part  514 , the hydrogen supply pipe  513  is provided with a fluid pressurization pump  512 . 
     The junction part  514  is composed of a piping joint with the hydrogen supply pipe  513  and the liquid supply pipe  506 . When reaching the junction part  514 , the hydrogen-containing gas and the liquid flow into a gas-liquid mixing pipe  51 , which is provided with a fluid pressurization pump  515 . This pump  515  pressurizes and sends the hydrogen-containing gas and the liquid toward the downstream side. A dissolution part  52  is provided at the downstream side of the fluid pressurization pump  515  on the gas-liquid mixing pipe  51 . In addition, a flow rate regulating valve  53  is provided at the downstream side of the dissolution part  52  on the gas-liquid mixing pipe  51 . 
     The dissolution part  52  is a tubular body having a larger inner diameter than the inner diameter of the gas-liquid mixing pipe  51  and includes a mixing body, such as a membrane filter, which has fine pores and is provided inside the dissolution part  52 . When the gas-liquid mixture of the hydrogen-containing gas and the liquid passes through the fine pores of the mixing body, such as a membrane filter, the hydrogen-containing gas becomes fine bubbles thereby to increase the contact surface area with the liquid. Moreover, the hydrogen-containing gas and the liquid are pressurized by the pressurizing force of the fluid pressurization pump  515  and the opening degree of the flow rate regulating valve  53 , and the hydrogen concentration can therefore be increased. The hydrogen-containing liquid of a high concentration thus obtained is supplied from the water delivery outlet  54  to a desired site. 
     Examples 
     Hydrogen concentration DH (mg/L) and pH of water generated in the cathode chamber  22  were measured when using the Kamakura city tap water (calcium hardness of 42.5 ppm and magnesium hardness of 18.5 ppm as the U.S. water hardness and pH 7.1) as the water containing a mineral component, using purified water (deionized water cartridge G-20 available from ORGANO CORPORATION) as the water substantially free from a mineral component, using the hydrogen water generator  1  of  FIG. 1  having one electrolyzer  2 , using the hydrogen water generator  1  of  FIG. 2  having two electrolyzers  2 , and changing the current flowing through the cathode  24 , the type of water in the anode chamber  21 , the flow rate of water in the cathode chamber  22 , and the water pressure in the cathode chamber  22 . Results are listed in Table 1. 
     
       
         
           
               
               
               
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                   
                   
                 Cathode water 
                 Cathode inner 
                 DH 
                   
               
               
                 Current 
                 Anode water 
                 flow rate 
                 pressure (MPa) 
                 (mg/L) 
                 pH 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                 6 A × 1 bath 
                 Purified water (stored) 
                 1.0 L/min 
                 0.1 
                 1.3 
                 7.09 
               
               
                   
                   
                   
                 0.2 
                 1.6 
                 6.93 
               
               
                   
                   
                   
                 0.3 
                 1.8 
                 6.91 
               
               
                 6 A × 1 bath 
                 Tap water flowing 
                 1.0 L/min 
                 0.1 
                 1.3 
                 8.42 
               
               
                   
                 Flow rate of 1.0 L/min 
                   
                 0.2 
                 1.5 
                 8.42 
               
               
                   
                 Anode chamber inner pressure = 
                   
                 0.3 
                 1.8 
                 8.21 
               
               
                   
                 Cathode chamber inner pressure 
               
               
                 6 A × 1 bath 
                 Purified water (stored) 
                 2.0 L/min 
                 0.1 
                 0.9 
                 7.09 
               
               
                   
                   
                   
                 0.2 
                 1.0 
                 6.99 
               
               
                   
                   
                   
                 0.3 
                 1.1 
                 6.97 
               
               
                 6 A × 1 bath 
                 Tap water flowing 
                 2.0 L/min 
                 0.1 
                 0.9 
                 7.88 
               
               
                   
                 Flow rate of 2.0 L/min 
                   
                 0.2 
                 1.1 
                 8.38 
               
               
                   
                 Anode chamber inner pressure = 
                   
                 0.3 
                 1.1 
                 9.32 
               
               
                   
                 Cathode chamber inner pressure 
               
               
                 6 A × 2 baths 
                 Purified water (stored) 
                 1.0 L/min 
                 0.1 
                 1.8 
                 7.09 
               
               
                   
                   
                   
                 0.2 
                 2.2 
                 6.98 
               
               
                   
                   
                   
                 0.3 
                 2.5 
                 6.92 
               
               
                 6 A × 2 baths 
                 Tap water flowing 
                 1.0 L/min 
                 0.1 
                 1.9 
                 9.36 
               
               
                   
                 Flow rate of 1.0 L/min 
                   
                 0.2 
                 2.2 
                 9.85 
               
               
                   
                 Anode chamber inner pressure = 
                   
                 0.3 
                 2.5 
                 9.68 
               
               
                   
                 Cathode chamber inner pressure 
               
               
                 6 A × 2 baths 
                 Purified water (stored) 
                 2.0 L/min 
                 0.1 
                 1.4 
                 7.11 
               
               
                   
                   
                   
                 0.2 
                 1.8 
                 7.04 
               
               
                   
                   
                   
                 0.3 
                 1.9 
                 7.03 
               
               
                 6 A × 2 baths 
                 Tap water flowing 
                 2.0 L/min 
                 0.1 
                 1.5 
                 9.57 
               
               
                   
                 Flow rate of 2.0 L/min 
                   
                 0.2 
                 1.7 
                 9.86 
               
               
                   
                 Anode chamber inner pressure = 
                   
                 0.3 
                 1.8 
                 9.67 
               
               
                   
                 Cathode chamber inner pressure 
               
               
                   
               
            
           
         
       
     
     &lt;&lt;Consideration&gt;&gt; 
     When the water supplied to the anode chamber  21  is water that is substantially free from a mineral component, pH of the hydrogen water generated in the cathode chamber  22  is 6.91 to 7.11, that is, neutral. In contrast, when the water supplied to the anode chamber  21  is water that contains a mineral component (specifically, tap water), pH of the hydrogen water generated in the cathode chamber  22  is 7.88 to 9.86, that is, alkaline. 
     When one electrolyzer  2  is used as illustrated in  FIG. 1  and the water supplied to the anode chamber  21  is water that is substantially free from a mineral component, the concentration DH of hydrogen water is 1.6 mg/L or more with the setting in which the current flowing through the cathode  24  is 6 A or more, the supply amount of water to the cathode chamber  22  is 1.0 L/min or less, and the pressure of water supplied to the cathode chamber  22  is 0.2 MPa or more. When two electrolyzers  2  are used as illustrated in  FIG. 2  and the water supplied to the anode chamber  21  is water that is substantially free from a mineral component, the concentration DH of hydrogen water is 1.6 mg/L or more with the setting in which the current flowing through each cathode  24  is 6 A or more, the supply amount of water to the cathode chamber  22  is 1.0 L/min or less, and the pressure of water supplied to the cathode chamber  22  is 0.1 MPa or more, or with the setting in which the current flowing through each cathode  24  is 6 A or more, the supply amount of water to the cathode chamber  22  is 2.0 L/min or less, and the pressure of water supplied to the cathode chamber  22  is 0.2 MPa or more. 
     When one electrolyzer  2  is used as illustrated in  FIG. 1  and the water supplied to the anode chamber  21  is water that contains a mineral component, the concentration DH of hydrogen water is 1.6 mg/L or more with the setting in which the current flowing through the cathode  24  is 6 A or more, the supply amount of water to the cathode chamber  22  is 1.0 L/min or less, and the pressure of water supplied to the cathode chamber  22  is 0.3 MPa or more. When two electrolyzers  2  are used as illustrated in  FIG. 2  and the water supplied to the anode chamber  21  is water that contains a mineral component, the concentration DH of hydrogen water is 1.6 mg/L or more with the setting in which the current flowing through each cathode  24  is 6 A or more, the supply amount of water to the cathode chamber  22  is 1.0 L/min or less, and the pressure of water supplied to the cathode chamber  22  is 0.1 MPa or more, or with the setting in which the current flowing through each cathode  24  is 6 A or more, the supply amount of water to the cathode chamber  22  is 2.0 L/min or less, and the pressure of water supplied to the cathode chamber  22  is 0.2 MPa or more. 
     Then, hydrogen concentration DH (mg/L) and pH of water generated in the cathode chamber  22  were measured over time when using the Kamakura city tap water (calcium hardness of 42.5 ppm and magnesium hardness of 18.5 ppm as the U.S. water hardness and pH 7.01) as the water containing a mineral component, using the hydrogen water generator  1  of  FIG. 1  having one electrolyzer  2 , storing the tap water in the anode chamber  21  (closing the valve  92 ), setting the current flowing through the cathode  24  at 6 A, setting the flow rate of water in the cathode chamber  22  at 1 L/min, and setting the water pressure in the cathode chamber  22  at 0.2 MPa. Results are listed in Table 2. 
     
       
         
           
               
               
               
               
               
               
             
               
                 TABLE 2 
               
               
                   
               
               
                   
                 Anode water = Tap water flowing 
                   
                   
                   
                   
               
               
                   
                 Anode chamber inner pressure = Cathode 
                 Cathode water 
                 Cathode inner 
                 DH 
               
               
                 Current 
                 chamber inner pressure 
                 flow rate 
                 pressure (MPa) 
                 (mg/L) 
                 pH 
               
               
                   
               
             
            
               
                 6 A × 1 bath 
                 When flowing water at flow rate of 1.0 L/min 
                 1.0 L/min 
                 0.2 
                 1.8 
                 8.50 
               
               
                   
                 Immediately after stopping water supply 
                   
                   
                 1.8 
                 8.41 
               
               
                   
                 1 min after stopping water supply 
                   
                   
                 1.8 
                 7.21 
               
               
                   
                 3 min after stopping water supply 
                   
                   
                 1.9 
                 7.03 
               
               
                   
               
            
           
         
       
     
     &lt;&lt;Consideration&gt;&gt; 
     While the tap water is flowing through the anode chamber  21  at a flow rate of 1.0 L/min, pH of the hydrogen water is about 8.50, that is, alkaline, but pH comes close to neutrality immediately after stopping the water flow. When one minute has passed after stopping the water flow, pH is 7.2, that is, neutral. When three minutes have passed after stopping the water flow, pH is 7.03, that is, neutral. 
     Then, hydrogen concentration DH (mg/L) and pH of water generated in the cathode chamber  22  were measured when using the Kamakura city tap water (calcium hardness of 42.5 ppm and magnesium hardness of 18.5 ppm as the U.S. water hardness and pH 7.04) as the water containing a mineral component, using the hydrogen water generator  1  of  FIG. 3  having one electrolyzer  2 , supplying purified water, 0.01% calcium sulfate solution, and 0.1% calcium sulfate solution to the space between the anode  23  and the cation exchange membrane  25 , setting the current flowing through the cathode  24  at 6 A, setting the flow rate of water in the cathode chamber  22  at 1 L/min, and setting the water pressure in the cathode chamber  22  at 0.2 MPa. Results are listed in Table 3. 
     
       
         
           
               
               
               
               
               
               
             
               
                 TABLE 3 
               
               
                   
               
               
                   
                   
                 Cathode water 
                 Cathode inner 
                 DH 
                   
               
               
                 Current 
                 Between anode and membrane 
                 flow rate 
                 pressure (MPa) 
                 (mg/L) 
                 pH 
               
               
                   
               
             
            
               
                 6 A × 1 bath 
                 Purified water sprayed 
                 1.0 L/min 
                 0.2 
                 1.6 
                 6.98 
               
               
                   
                 0.01% calcium sulfate solution 
                   
                   
                 1.6 
                 7.10 
               
               
                   
                 0.1% calcium sulfate solution 
                   
                   
                 1.6 
                 7.05 
               
               
                   
               
            
           
         
       
     
     &lt;&lt;Consideration&gt;&gt; 
     When the hydrogen water generator illustrated in  FIG. 3  is used and the space between the anode  23  and the cation exchange membrane  25  is supplied with any of the purified water and the water which contains a mineral component, neutral hydrogen water of DH=1.6 is obtained 
     Then, hydrogen concentration DH (mg/L) and pH of water generated in the cathode chamber  22  were measured when using the Kamakura city tap water (calcium hardness of 42.5 ppm and magnesium hardness of 18.5 ppm as the U.S. water hardness and pH 7.1) as the water containing a mineral component, using the hydrogen water generator  1  of  FIG. 2  having two electrolyzers  2 , setting the current flowing through each cathode  24  at 6 A, setting the flow rate of water in the cathode chamber  22  at 1 L/min, setting the water pressure in the cathode chamber  22  at 0.2 MPa, leaving the hydrogen water generator  1  for two days so that the mineral component would attach to the cation exchange membrane  25 , the anode  23 , and the cathode  24 , generating hydrogen water for five minutes using the hydrogen water generator  1 , then performing reverse washing with a reversed DC voltage for 30 seconds, and returning the polarity to the original state to generate hydrogen water for one minute. Measurement results are listed in Table 4. 
     
       
         
           
               
               
               
               
               
               
             
               
                 TABLE 4 
               
               
                   
               
               
                   
                 Anode water = Tap water flowing 
                   
                 Cathode inner 
                   
                   
               
               
                   
                 Anode chamber inner pressure = Cathode 
                 Cathode water 
                 pressure 
                 DH 
               
               
                 Current 
                 chamber inner pressure 
                 flow rate 
                 (MPa) 
                 (mg/L) 
                 pH 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                 6 A × 2 baths 
                 Immediately after water supply 
                 1 L/min 
                 0.2 
                 — 
                 10.44 
               
               
                   
                 1 min after water supply 
                   
                   
                 2.5 
                 9.55 
               
               
                   
                 2 min after water supply 
                   
                   
                 — 
                 9.19 
               
               
                   
                 3 min after water supply 
                   
                   
                 2.8 
                 8.95 
               
               
                   
                 4 min after water supply 
                   
                   
                 — 
                 8.72 
               
               
                   
                 5 min after water supply 
                   
                   
                 2.3 
                 8.72 
               
            
           
           
               
            
               
                 Reverse washing for 30 seconds (Passing tap water 
               
               
                 through anode chamber and cathode chamber at 1 L/min. 
               
               
                 Anode chamber inner pressure = Cathode chamber inner pressure) 
               
            
           
           
               
               
               
               
               
               
            
               
                 6 A × 2 baths 
                 1 min after water supply 
                 1 L/min 
                 0.2 
                 2.6 
                 9.54 
               
               
                   
               
            
           
         
       
     
     &lt;&lt;Consideration&gt;&gt; 
     When the hydrogen water generator is activated after being left for a long time, highly-alkaline hydrogen water is generated immediately after water supply, but pH decreases in about four minutes. However, the reverse washing is performed to remove the mineral component attached to the cathode  24 , highly alkaline hydrogen water is generated again. 
     Then, hydrogen concentration DH (mg/L) and pH of water generated in the cathode chamber  22  were measured when using the Kamakura city tap water (calcium hardness of 42.5 ppm and magnesium hardness of 18.5 ppm as the U.S. water hardness and pH 7.08) as the water containing a mineral component, using the hydrogen water generator  1  of  FIG. 1  having one electrolyzer  2 , setting the flow rate of tap water supplied to the anode chamber  21  at 0.5 L/min, 1.0 L/min, and 1.5 L/min, setting the current flowing through the cathode  24  at 6 A, setting the flow rate of water in the cathode chamber  22  at 1 L/min, and setting the water pressure in the cathode chamber  22  at 0.2 MPa. Results are listed in Table 5. 
     
       
         
           
               
               
               
               
               
               
               
             
               
                 TABLE 5 
               
               
                   
               
               
                   
                 Cathode 
                 Cathode inner 
                 Anode 
                 Anode inner 
                   
                   
               
               
                   
                 water flow 
                 pressure 
                 water flow 
                 pressure 
                 DH 
               
               
                 Current 
                 rate 
                 (MPa) 
                 rate 
                 (MPa) 
                 (mg/L) 
                 pH 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
            
               
                 6 A × 1 bath 
                 1.0 L/min 
                 0.2 
                 0 (Water supply 
                 0 
                 1.7 
                 7.07 
               
               
                   
                   
                   
                 stopped) 
               
               
                   
                   
                   
                 0.005 L/min  
                 0.2 
                 1.6 
                 7.06 
               
               
                   
                   
                   
                 0.5 L/min 
                 0.2 
                 1.7 
                 7.67 
               
               
                   
                   
                   
                 1.0 L/min 
                 0.2 
                 1.6 
                 8.16 
               
               
                   
                   
                   
                 1.5 L/min 
                 0.2 
                 1.6 
                 9.78 
               
               
                   
               
            
           
         
       
     
     &lt;&lt;Consideration&gt;&gt; 
     The hydrogen water delivered from the cathode chamber  22  becomes highly alkaline by adjusting the flow rate of water supplied to the anode chamber  21  which contains a mineral component, that is, by increasing the flow rate of water supplied to the anode chamber  21  which contains a mineral component (so that, for example, the ratio of the flow rate in the anode chamber  21  to the flow rate in the cathode chamber  22  is one or more) while, in contrast, the hydrogen water delivered from the cathode chamber  22  becomes neutral or comes close to neutrality by reducing the flow rate of water supplied to the anode chamber  21  which contains a mineral component (so that, for example, the ratio of the flow rate in the anode chamber  21  to the flow rate in the cathode chamber  22  is less than one). In particular, when the flow rate in the anode chamber  21  is reduced to generate neutral hydrogen water, the drainage water from the anode chamber  21  (discharge amount) can be reduced. When generating alkaline hydrogen water, it may be delivered after being mixed with the hydrogen water generated in the cathode chamber  22  in order to save the effort of discharge. 
     Then, hydrogen concentration DH (mg/L) and pH of water generated in the cathode chamber  22  of the second-stage electrolyzer  2  were measured when using the Kamakura city tap water (calcium hardness of 42.5 ppm and magnesium hardness of 18.5 ppm as the U.S. water hardness and pH 7.08) as the water containing a mineral component, using the hydrogen water generator  1  of  FIG. 2B  having two electrolyzers  2 , setting the flow rate of tap water supplied to the anode chamber  21  of the second-stage electrolyzer  2  at 0.43 L/min, setting the current flowing through the cathode  24  of the first-stage electrolyzer  2  at 1.5 A, setting the current flowing through the cathode  24  of the second-stage electrolyzer  2  at 6 A, setting the flow rate of water in the cathode chamber  22  of the second-stage electrolyzer  2  at 1 L/min, and setting the water pressure in the cathode chamber  22  of the second-stage electrolyzer  2  at 0.2 MPa. Results are listed in Table 6. 
     
       
         
           
               
               
               
               
               
               
               
             
               
                 TABLE 6 
               
               
                   
               
               
                   
                 Cathode 
                 Cathode inner 
                 Anode 
                 Anode inner 
                   
                   
               
               
                   
                 water flow 
                 pressure 
                 water flow 
                 pressure 
                 DH 
               
               
                 Current 
                 rate 
                 (MPa) 
                 rate 
                 (MPa) 
                 (mg/L) 
                 pH 
               
               
                   
               
             
            
               
                 First-stage electrolyzer: 1.5 A 
                 1.0 L/min 
                 0.2 
                 0.43 L/min 
                 0.2 
                 1.6 
                 9.58 
               
               
                 Second-stage electrolyzer: 6 A 
               
               
                   
               
            
           
         
       
     
     &lt;&lt;Consideration&gt;&gt; 
     In the hydrogen water generator of Table 1 having one electrolyzer, the condition for increasing both the hydrogen concentration and the alkalinity is limited, but according to this example, highly-alkaline hydrogen water having a saturated hydrogen concentration can be generated. 
     DESCRIPTION OF REFERENCE NUMERALS 
     
         
           1  Hydrogen water generator 
           2  Electrolyzer 
           20  Housing 
           21  Anode chamber 
           211  Inlet for water for electrolysis Wa 
           212  Outlet for water for electrolysis Wa 
           22  Cathode chamber 
           221  Inlet for water for electrolysis Wc 
           222  Outlet for water for electrolysis Wc 
           23  Anode 
           24  Cathode 
           25  Membrane 
           3  Electric power source 
           31  Plug 
           32  AC/DC converter 
           4  First supply system 
           41  Tap water source 
           42  Pipework 
           43  Opening/closing valve 
           5  Water delivery system 
           51  Pipework (Gas-liquid mixing pipe) 
           52  Dissolution part 
           53  Flow rate regulating valve 
           54  Water delivery outlet 
           6  Second supply system 
           61  Tank 
           62  Pipework 
           63  Pump 
           7  Third supply system 
           71  Pipework 
           8  Switch 
           9  Drain system 
           91  Pipework 
           92  Opening/closing valve 
         Wa, Wc Water for electrolysis