Patent Abstract:
The present invention discloses an electrolytic apparatus comprising:
       an electrolytic bath in which an anode (I) of a silver electrode—a cathode (II) of an inert electrode—an anode (III) of an inert electrode are arranged in this order in parallel to one another, and an electrode pair of the anode (I)—the cathode (II) and an electrode pair of the cathode (II)—the anode (III) have an electrical circuit configured to apply a potential of 2.07 V or more to the electrode pair of the cathode (II)—the anode (III) to supply electrolytic current, when independently supplying the electrolytic current;   an electrolytic raw water supply pipe configured to supply electrolytic raw water into the electrolytic bath; and   an electrolyzed water extraction pipe configured to extract the electrolyzed water in the electrolytic bath to the outside.

Full Description:
BACKGROUND 
     1. Technical Field 
     The present invention relates to an electrolytic apparatus, an ice making apparatus incorporating the electrolytic apparatus, and an ice making method, in particular, to an electrolytic apparatus, an ice making apparatus, and an ice making method that suppress a growth of mold (fungi) or bacteria in the ice making apparatus over a subsequent operation of the apparatus during startup of the ice making apparatus. 
     2. Related Art 
     Methods of performing electrolysis using a silver electrode for an anode, and a silver electrode or an inert electrode or other electrodes for a cathode based on dilute electrolyte solution containing chloride or tap water as raw water to generate electrolytic silver or silver nitrate are widely known techniques. For a long time, silver has been said to have bactericidal capacity, used for control of mold and bacteria, such as anti-bacteria, and used from the viewpoint of hygiene, such as sterilized water (for example, JP 2007-85699 A). 
     The bacterial control using silver ions of JP 2007-85699 A, an electrolyzed water generation mechanism is installed on a raw water side of the ice making apparatus. The electrolyzed water generation mechanism generates silver ions by applying direct current to a pair of silver electrodes. An internal path and ice are sterilized by supplying the electrolyzed water (ice making water) containing silver ions into the ice making apparatus to make ice. 
     However, JP 2007-85699 A suggests the use of electrolytic raw water, that is, tap water obtained by performing dechlorination or the like as electrolytic solution. In addition, since the reaction is slow in silver ionized water, there are problems in that mold and bacteria are likely to occur in the apparatus during startup of the ice making apparatus, and slime due to the growth of mold and bacteria is likely to occur on a bottom surface of an ice making water tank. 
     SUMMARY 
     An object of the invention is to provide an electrolytic apparatus, an ice making apparatus incorporating the electrolytic apparatus, and an ice making method for solving the above-described problems of the prior art that suppress the growth of mold or bacteria in the ice making apparatus over a subsequent operation of the apparatus during startup of the ice making apparatus. 
     As a result of extensive studies on the above-described problems, the present inventors or the like have found the followings. 
     In the electrolytic apparatus, when a silver electrode is used in the anode, silver is dissolved as silver ions and reacts with chloride ions, nitric acid ions or the like of anion in the raw water, thereby producing silver salt such as silver chloride and silver nitrate. When the silver salt is silver chloride, most of silver chloride form insoluble colloidal salt due to low solubility. When the silver chloride is excessively generated, a precipitate is also formed. The electrolyzed water containing the insoluble colloidal silver chloride also has a function of realizing sterilization in a small amount, similarly to soluble silver ion electrolyzed water. However, since the reaction is slow, the time taken until mold and bacteria die is long. 
     In addition, since an oxidation-reduction potential of ozone is 2.07 V, ozone is generated by applying the potential of 2.07 V or more to the electrode using an inert electrode such as platinum or a platinum alloy in the anode to oxidize and electrolyze water. Electrolytic generation of ozone has been known for a long time, and ozone water obtained by dissolving ozone in water has been widely used. The electrolytic generation ozone water has been mainly used in the control of mold and bacteria such as sterilization, used in tap water, pool water or the like, and used in the control of mold and bacteria. 
     The inventors or the like configured an electrolytic apparatus in which three electrode plates are arranged in an order of an anode (I), a cathode (II), and an anode (III), a silver electrode is used in the anode (I), an inert electrode such as platinum and a platinum alloy is used in the cathode (II) and the anode (III), and an electrode pair of the anode (I)—the cathode (II) and an electrode pair of the cathode (II)—the anode (III) are set as electrical circuits for independently supplying electrolytic current, respectively. The inventions have found that when the apparatus is incorporated into an ice making apparatus, it is possible to generate ozone water during startup of the ice making apparatus, and generate electrolyzed water containing insoluble colloidal silver chloride during a subsequent operation, and as a result, it is possible to suppress growth of mold or bacteria in the ice making apparatus during startup of the ice making apparatus by ozone water, and it is possible to suppress subsequent growth of mold and bacteria by silver chloride colloidal water, and thus have accomplished the present invention. 
     To accomplish the above-described object, the invention is described below. 
     [1] An electrolytic apparatus comprising: 
     an electrolytic bath in which an anode (I) of a silver electrode—a cathode (II) of an inert electrode—an anode (III) of an inert electrode are arranged in this order in parallel to one another, and an electrode pair of the anode (I)—the cathode (II) and an electrode pair of the cathode (II)—the anode (III) have an electrical circuit configured to independently supply electrolytic current; 
     an electrolytic raw water supply pipe configured to supply electrolytic raw water into the electrolytic bath; and 
     an electrolyzed water extraction pipe configured to extract the electrolyzed water in the electrolytic bath to the outside. 
     [2] An electrolytic apparatus comprising: 
     an electrolytic bath in which an anode (I) of a silver electrode—a cathode (II) of an inert electrode—an anode (III) of an inert electrode are arranged in this order in parallel to one another, the cathode (II) partitions the interior of the cell into a space having an electrode pair of the anode (I)—the cathode (II) and a space having an electrode pair of the cathode (II)—the anode (III) in a liquid-tight manner, and the electrode pair of the anode (I)—the cathode (II) and the electrode pair of the cathode (II)—the anode (III) have an electrical circuit configured to independently supply electrolytic current; 
     an electrolytic raw water supply pipe configured to supply the electrolytic raw water between the electrode pair of the anode (I)—the cathode (II) and between the electrode pair of the cathode (II)—the anode (III) in the electrolytic bath; and 
     an electrolyzed water extraction pipe configured to extract the electrolyzed water between the electrode pair of the anode (I)—the cathode (II) and between the electrode pair of the cathode (II)—the anode (III) in the electrolytic bath to the outside. 
     [3] An electrolytic apparatus comprising: 
     an electrolytic bath in which an anode (I) of a silver electrode—a cathode (II) of an inert electrode—an anode (III) of an inert electrode are arranged in this order in parallel to one another, the cathode (II) partitions the interior of the cell into a space having an electrode pair of the anode (I)—the cathode (II) and a space having an electrode pair of the cathode (II)—the anode (III) in a liquid-tight manner, and the electrode pair of the anode (I)—the cathode (II) and the electrode pair of the cathode (II)—the anode (III) have an electrical circuit configured to independently supply electrolytic current; 
     a communicating pipe that connects one end side of the space having the electrode pair of the anode (I)—the cathode (II) and one end side of the space having the electrode pair of the cathode (II)—the anode (III) in the electrolytic bath; 
     an electrolytic raw water supply pipe configured to supply the electrolytic raw water to one of the other end side of the space having the electrode pair of the anode (I)—the cathode (II) and the other end side of the space having the electrode pair of the cathode (II)—the anode (III) in the electrolytic bath; and 
     an electrolyzed water extraction pipe configured to extract the electrolyzed water outward to the other side of the other end side of the space having the electrode pair of the anode (I)—the cathode (II) and the other end side of the space having the electrode pair of the cathode (II)—the anode (III) in the electrolytic bath. 
     [4] An electrolytic apparatus comprising: 
     an ice making apparatus housing; 
     an ice stocker attached to a bottom of the ice making apparatus housing; 
     an ice making water tank disposed above the ice stocker; 
     a water spray tank disposed above the ice making water tank, and having a through-hole formed through a bottom wall of the water spray tank; 
     a freezing pipe which is inserted into the through-hole of the water spray tank at an interval spaced from the inner wall of the through-hole at one end side of the freezing pipe, and disposed toward the upper surface of the ice making water tank at the other end side of the freezing pipe; 
     a water supply pipe configured to connect the ice making water tank and the water spray tank, and interposing a water supply pump configured to supply a predetermined amount of ice making water in the ice making water tank to the water spray tank; 
     an ice making water supply pipe configured to supply the ice making water to the ice making water tank; 
     a medium supplying means configured to alternately supply refrigerant or heat medium into the freezing pipe; and 
     the electrolytic apparatus according to any one of [1] to [3] interposed in the ice making water supply pipe and/or the water supply pipe. 
     [5] An ice making method using the ice making apparatus according to [4], wherein 
     during startup of the ice making apparatus, electric current is applied to the electrode pair of the cathode (II)—the anode (III) to generate ozone water, and after a predetermined time of the startup of the ice making apparatus, the generation of ozone water is stopped and electric current is applied to the electrode pair of the anode (I)—the cathode (II) to generate silver chloride colloidal water. 
     According to the invention, the electrolytic apparatus is configured such that three electrode plates are arranged in the order of the anode (I), the cathode (II), and the anode (III), the silver electrode is used in the anode (I), and an inert electrode such as platinum and a platinum alloy is used in the cathode (II) and the anode (III), and the electrolytic current is independently applied to the electrode pair of the anode (I)—the cathode (II) and the electrode pair of the cathode (II)—the anode (III), respectively. Accordingly, it is possible to supply ozone water, and silver-containing water at arbitrarily timing in a single electrolytic apparatus. When the electrolytic apparatus is incorporated into the ice making apparatus, ozone water of sterilization immediate effect can be generated during startup of the ice making apparatus, and the electrolyzed water containing insoluble colloidal silver chloride having sterilization slow-acting properties can be generated during the subsequent operation. Thus, it is possible to suppress growth of mold and bacteria in the ice making apparatus during startup of the ice making apparatus by ozone water, and suppress preventing the subsequent growth of mold and bacteria by silver chloride colloidal water. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic diagram illustrating a configuration of a positional relation among three electrode plates in one example of the electrolytic apparatus of the invention, and flows of electrolytic raw water and electrolyzed water; 
         FIG. 2  is a schematic diagram illustrating a configuration of a positional relation among three electrode plates in another example of the electrolytic apparatus of the invention, and flows of electrolytic raw water and electrolyzed water; 
         FIGS. 3A and 3B  are schematic diagrams illustrating a configuration of a positional relation among three electrode plates in still another example of the electrolytic apparatus of the invention, and flows of electrolytic raw water and electrolyzed water, and the flows of electrolytic raw water and electrolyzed water being in opposite directions to each other in  FIGS. 3A and 3B ; 
         FIG. 4  is a schematic diagram illustrating a configuration of a positional relation among three electrode plates in still another example of the electrolytic apparatus of the invention, and flows of electrolytic raw water and electrolyzed water; 
         FIG. 5  is a schematic explanatory diagram illustrating of an operation of the electrolytic apparatus of the invention based on the example of  FIG. 1 ; and 
         FIG. 6  is a schematic diagram illustrating a configuration of an example of an ice making apparatus of the invention incorporating the electrolytic apparatus of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, the present invention will be described in detail. 
     An electrolytic apparatus of the invention will be described with reference to examples of  FIGS. 1 to 4 . 
       FIG. 1  is a schematic diagram illustrating a configuration of a positional relation among three electrode plates in one example of the electrolytic apparatus of the invention, and flows of electrolytic raw water and electrolyzed water. In  FIG. 1 , an electrolytic apparatus  2  has an electrolytic bath  4 , an electrolytic raw water supply pipe  6 , and an electrolyzed water extraction pipe  8 . 
     In the electrolytic bath  4 , an anode (I) of a silver electrode—a cathode (II) of an inert electrode—an anode (III) of an inert electrode are arranged in this order in parallel to one another. An electrode pair of the anode (I)—the cathode (II) and an electrode pair of the cathode (II)—the anode (III) have an electrical circuit configured to independently supply electrolytic current, respectively. Electric current can be individually or simultaneously applied to the electrode pairs. As the inert electrode, it is possible to use platinum-based electrodes such as platinum or platinum alloy. 
     When raw water is taken in an R direction from the electrolytic raw water supply pipe  6 , when only the anode (I) of the silver electrode and the cathode (II) of the platinum-based electrode are applied with electric current, silver ions are generated, the silver ions react with chlorine ions in the raw water, and thus most of the silver ions form an insoluble silver chloride colloid. Meanwhile, when only cathode (II) of the platinum-based electrode and anode (III) of the platinum-based electrode are applied with electric current, oxygen and ozone are generated from the anode. In  FIG. 1 , reference numeral G is an arrow indicating a flow direction of the electrolyzed water. 
       FIG. 2  is a schematic diagram illustrating a positional relation among three electrode plates in another example of the electrolytic apparatus of the invention, and flows of electrolytic raw water and electrolyzed water. In  FIG. 2 , an electrolytic apparatus  12  has an electrolytic bath  14 , an electrolytic raw water supply pipe  16  including an electrolytic raw water supply main pipe  16   t  and branch pipes  16   a  and  16   b  thereof, and an electrolyzed water extraction pipe  18  including an electrolyzed water extraction main pipe  18   t  and branch pipes  18   a  and  18   b  thereof. In the electrolytic bath  14 , the anode (I) of the silver electrode—the cathode (II) of the inert electrode—the anode (III) of the inert electrode are arranged in this order in parallel to one another, and the interior of the electrolytic bath  14  is divided into a space having the electrode pair of the anode (I)—the cathode (II) and a space having the electrode pair of the cathode (II)—the anode (III) the by cathode (II) in a liquid-tight manner. 
     In the electrolytic apparatus  12  thus configured, water taken in the R direction passes through the space having the electrode pair of the anode (I)—the cathode (II) and the space having the electrode pair of the cathode (II)—the anode (III) by divided flows Ra and Rb, respectively. During passage, in the example of  FIG. 2 , silver ionized water and ozone water are generated, respectively, based on the same principle as the example of  FIG. 1 . 
     That is, in the electrolytic apparatus  12 , raw water is taken in the R direction from the electrolytic raw water supply pipe  16 , then, when the raw water passes through only the anode (I) of the silver electrode and the cathode (II) of the platinum-based electrode, silver ionized water (divided flow Ga) is generated from the divided flow Ra of the raw water R, the silver ions react with chloride ions in the raw water, and most of the silver ions form an insoluble silver chloride colloid. Meanwhile, when the electric current is applied only to cathode (II) of platinum-based electrode and anode (III) of the platinum-based electrode, electrolyzed water (divided flow Gb) containing oxygen and ozone is generated from the divided flow Rb of the raw water R. 
       FIGS. 3A and 3B  are schematic diagrams illustrating a configuration of a positional relation among three electrode plates in still another example of the electrolytic apparatus of the invention, and flows of electrolytic raw water and electrolyzed water. In both  FIGS. 3A and 3B , an electrolytic apparatus  22  and an electrolytic bath  24  are illustrated. 
     In the electrolytic bath  24 , the anode (I) of the silver electrode—the cathode (II) of the inert electrode—the anode (III) of the inert electrode are arranged in this order in parallel to one another, and the electrolytic bath  24  is divided into a space having the electrode pair of the anode (I)—the cathode (II) and a space having the electrode pair of the cathode (II)—the anode (III) by the cathode (II) in a liquid-tight manner. 
     The electrolytic apparatus  22  has the electrolytic bath  24 , a communicating pipe  26  that connects one end side of the space having the electrode pair of the anode (I)—the cathode (II) and one end side of the space having the electrode pair of the cathode (II)—the anode (III), a connecting pipe  28   a  attached to the other end side of the space having the electrode pair of the anode (I)—the cathode (II), and a connecting pipe  28   b  attached to the other end side of the space having the electrode pair of the cathode (II)—the anode (III). 
     In  FIGS. 3A and 3B , the flows of the electrolytic raw water and the electrolyzed water are in the opposite directions. 
     Therefore, in  FIG. 3A , raw water is taken in the R direction from the connecting pipe  28   a  of the space having the electrode pair of the anode (I)—the cathode (II), and the electric current is applied only to cathode (II) of the platinum-based electrode and anode (III) of the platinum-based electrode. After passing through the space having the electrode pair of the anode (I)—the cathode (II) in a Ra direction, the taken raw water R passes through the space having the electrode pair of the cathode (II)—the anode (III) in a Rb direction via the communicating pipe  26 . Electrolyzed water containing oxygen and ozone is generated from the raw water during passage in the Rb direction, and the electrolyzed water is extracted in a G direction via the connecting pipe  28   b  of the space having the electrode pair of the cathode (II)—the anode (III). In the example of  FIG. 3A , the connecting pipe  28   a  plays the role of an electrolytic raw water supply pipe, and the connecting pipe  28   b  plays the role of an electrolyzed water extraction pipe. 
     On the other hand, in  FIG. 3B , raw water is taken in the R direction from the connecting pipe  28   b  of the space having the electrode pair of the cathode (II)—the anode (III), and electric current is applied only to the anode (I) of the silver electrode and the cathode (II) of the platinum-based electrode. After passing through the space having the electrode pair of the cathode (II)—the anode (III) in the Rb direction, the taken raw water R passes through the space having the electrode pair of the anode (I)—the cathode (II) in the Ra direction via the communicating pipe  26 . Silver ionized water is generated from the raw water during passage in the Ra direction, the silver ions react with the chlorine ions in the raw water, and most of the silver ions form insoluble silver chloride colloid. The obtained silver chloride colloidal water is extracted in the G direction via the connecting pipe  28   a  of the space having the electrode pair of the anode (I)—the cathode (II). In the example of  FIG. 3B , the connecting pipe  28   b  plays the role of an electrolytic raw water supply pipe, and the connecting pipe  28   a  plays the role of an electrolyzed water extraction pipe. 
       FIG. 4  is a schematic diagram illustrating a configuration of a positional relation among three electrode plates in still another example of the electrolytic apparatus of the invention, and flows of electrolytic raw water and electrolyzed water. In  FIG. 4 , an electrolytic apparatus  32  has an electrolytic bath  34 , an electrolytic raw water supply pipe  36  including an electrolytic raw water supply main pipe  36   t  and branch pipes  36   a  and  36   b  thereof, a connecting pipe  38   a  of a space having an electrode pair of the anode (I)—the cathode (II), and a connecting pipe  38   b  of a space having an electrode pair of the cathode (II)—anode (III). In the electrolytic bath  34 , the anode (I) of the silver electrode-the cathode (II) of the inert electrode—the anode (III) of the inert electrode are arranged in this order in parallel to one another, and the interior of the electrolytic bath  34  is divided into the space having the electrode pair of the anode (I)—the cathode (II) and the space having the electrode pair of the cathode (II)—the anode (III) by the cathode (II) in a liquid-tight manner. 
     In the electrolytic apparatus  32  configured as described above, electric current is simultaneously applied to the electrode pair of the anode (I) of the silver electrode and the cathode (II) of the platinum-based electrode, and the electrode pair of the cathode (II) of the platinum based electrode and the anode (III) of the platinum-based electrode. Therefore, when the raw water taken in the R direction passes through the space having the electrode pair of the anode (I)—the cathode (II) and the space having the electrode pair of the cathode (II)—the anode (III) by the divided flows Ra and Rb, silver ionized water and ozone water are simultaneously generated and separately extracted. 
     That is, in the electrolytic apparatus  32 , when raw water is taken from the electrolytic raw water supply pipe  36  in the R direction, since electric current is applied to the anode (I) of the silver electrode and the cathode (II) of the platinum-based electrode, silver ionized water is generated from the divided flow Ra of raw water R, the silver ions react with the chlorine ions in the raw water, and most of the silver ions form an insoluble silver chloride colloid. The obtained silver chloride colloidal water is extracted in the Ga direction via the connecting pipe  38   a  of the space having the electrode pair of the anode (I)—the cathode (II). 
     Further, since electric current is also applied to the anode (II) of the platinum-based electrode and the cathode (III) of the platinum-based electrode, electrolyzed water containing oxygen and ozone is also generated from the divided flow Rb of raw water R, and extracted in the Gb direction via the connecting pipe  38   b  of the space having the electrode pair of the cathode (II)—the anode (III). 
     As illustrated in the examples of  FIGS. 1 to 4 , according to the electrolytic apparatus of the invention, it is possible to separately generate silver ionized water and ozone water in a single electrolytic bath, to generate mixed generation water of silver ions and ozone, or to separately generate silver ionized water and ozone water at the same time. 
       FIG. 5  is a schematic explanatory diagram illustrating the operation of the electrolytic apparatus of the invention based on the example of  FIG. 1 . 
     As illustrated in  FIG. 5 , in three electrode plates including the anode (I) of the silver electrode, the cathode (II) of the platinum-based inert electrode, and the anode (III) of the platinum-based inert electrode in the electrolytic bath  4 , the electrode pair of the anode (I)—the cathode (II), and the electrode pair of the cathode (II)—the anode (III) have an independent electrical circuit, respectively, and raw water is incorporated in the R direction from the electrolytic raw water supply pipe  6 . The raw water may be suitable for drinking in a dilute electrolyte solution, and may be, for example, tap water or the like. 
     When silver ionized water is collected as electrolyzed water, by turning on the electrical circuit between a wiring PI of the anode (I) and a wiring NIIa of the cathode (II) and turning off the electrical circuit between a wiring NIIb of the cathode (II) and a wiring PIII of the anode (III) to perform electrolysis, it is possible to extract only silver ionized water in the G direction from the electrolyzed water extraction pipe  8  as the electrolyzed water. 
     On the other hand, when the electrical circuit between a wiring NIIb of the cathode (II) and a wiring PIII of the anode (III) is turned on, and the electrical circuit between a wiring PI of the anode (I) and a wiring NIIa of the cathode (II) is turned off, ozone generation is obtained, and it is possible to extract electrolyzed water in the G direction from the electrolyzed water extraction pipe  8  as ozone water. 
     In  FIG. 5 , Ra is an arrow indicating a direction of flow of electrolytic raw water passing through the space having the electrode pair of the anode (I)—the cathode (II), and Rb is an arrow indicating a direction of flow of electrolytic raw water passing through the space having the electrode pair of the cathode (II)—the anode (III). 
       FIG. 6  is a schematic diagram illustrating a configuration of an example of the ice making apparatus of the invention incorporating the electrolytic apparatus of the invention. In  FIG. 6 , an ice making apparatus  42  includes: 
     an ice making apparatus housing  44 , 
     an ice stocker  46  attached to a bottom of the ice making apparatus housing  44 , 
     an ice making water tank  48  disposed above the ice stocker  46 , 
     a water spray tank  50  disposed above the ice making water tank  48 , and having a through-hole  51  formed through a bottom wall of the water spray tank  50 , 
     a freezing pipe  52  which is inserted into the through-hole  51  of the water spray tank  50  at an interval spaced from the inner wall of the through-hole  51  at one end side of the freezing pipe  52 , and disposed toward the upper surface of the ice making water tank  48  at the other end side of the freezing pipe  52 , 
     a water supply pipe  54  configured to connect the ice making water tank  48  and the water spray tank  50 , and interposing a water supply pump  56  configured to supply a predetermined amount of ice making water in the ice making water tank  48  to the water spray tank  50 , 
     an ice making water supply pipe  58  configured to supply the ice making water to the ice making water tank  48 , 
     a medium supplying means configured to alternately supply refrigerant or heat medium into the freezing pipe  52  (including refrigerant supplying means  60  and a heat medium supplying means  62  in  FIG. 6 ), and 
     the electrolytic apparatus  64  (interposed in the ice making water supply pipe  58  in  FIG. 6 ) interposed in the ice making water supply pipe  58  and/or the water supply pipe  54 . 
     An example of the ice making method of the invention using the ice making apparatus of the invention will be described below according to the example of  FIG. 6 . 
     As illustrated in  FIG. 6 , tap water applied to the ice making water supply pipe  58  from a faucet  66  is electrolyzed in the incorporated electrolytic apparatus  64  of the invention, converted to ice making water, and applied to the ice making water tank  48 . A water supply electromagnetic valve  68  is preferably provided in the ice making water supply pipe  58 . 
     In the electrolytic apparatus  64 , as described above, during startup of the ice making apparatus  42 , electric current is applied to the electrode pair of the cathode (II)—the anode (III) to generate ozone water, and the ozone water is used as the ice making water. After a predetermined period of time elapses from the startup of the ice making apparatus  42 , the generation of ozone water is stopped and electric current is applied to the electrode pair of the anode (I)—the cathode (II) to generate silver chloride colloidal water, and the silver chloride colloidal water is used as the ice making water. A predetermined time after the startup of the ice making apparatus  42  is preferably in a range of 30 seconds to 5 minutes, and in a range of ozone concentration of 0.3 ppm to 1.2 ppm. 
     The ice making water is stored in the ice making water tank  48 , and a predetermined amount thereof is applied to the water spray tank  50  provided above the ice making water tank  48  from the ice making water tank  48  by the water supply pump  56 . On the bottom wall of the water spray tank  50 , a through-hole  51  having an inverted trapezoidal cross-section including a through shaft to pass through the bottom wall, and one end of the freezing pipe  52  is inserted into the through-hole  51 . The other end of the freezing pipe  52  reaches the upper surface of the ice making water tank  48 . 
     A gap is formed between the through-hole  51  and one end of the freezing pipe  52  inserted thereto, and the ice making water in the water spray tank  50  flows down through the gap, and flows down along the surface of the freezing pipe  52 . The freezing pipe  52  is hollow tubing, and a sphere and a cylinder are continuous as a shape of the tubing. 
     Refrigerant and heat medium are alternately applied to the freezing pipe  52 . Ice making water flows down the surface of the freezing pipe  52  into which refrigerant such as cooling gas is conveyed and cooled, and freezes on the surface of the freezing pipe  52 . The refrigerant is produced by the refrigerant supplying means  60  placed on a shelf of the upper housing  44  of the ice making apparatus  42 , and conveyed into the freezing pipe  52  via a refrigerant conveying pipe (not illustrated). 
     When the sprayed ice making water is cooled on the surface of the freezing pipe  52  and a predetermined amount of ice  70  is grown, the water supply of the ice making water supply pipe  58  and the water supply pipe  54  is stopped. Thereafter, heat medium such as hot gas replacing the refrigerant is conveyed into the freezing pipe  52  to detach the ice  70  grown on the surface of the freezing pipe  52  from the freezing pipe  52  surface. Similarly to the refrigerant, the heat medium is produced by the heat medium supplying means  62  placed on the upper shelf of the housing  44  of the ice making apparatus  42 , delivered into the freezing pipe  52  via a heat medium conveying pipe (not illustrated), and replaced with the refrigerant. 
     The ice  70  detached from the surface of the freezing pipe  52  is stored in the ice stocker  46  disposed below the housing  44  of the ice making apparatus  42 . 
     Silver chloride colloid concentration in the electrolyzed water generated in the electrolytic apparatus  64  after a predetermined time of the startup of the ice making apparatus  42  is controlled by at least one of an electric conduction amount and an electric conduction time in the electrolytic apparatus  64 . The electric conduction amount and the electric conduction time of the electrolytic apparatus  64  are adjusted by a combination of a timer, current or the like starting from the electric conduction timing of the respective components of the ice making apparatus  42 , and the silver chloride colloid concentration of the electrolyzed water is preferably controlled to a range of 10 to 800 ppb. 
     The silver chloride colloid has a bactericidal action, and exhibits its effects at a low concentration. When the ice making water containing a predetermined amount of silver chloride colloid is sprayed and applied from the water spray tank  50 , silver chloride colloidal water flowing along the surface of the freezing pipe  52  is partially scattered to the periphery to sterilize the attachment surface attached to the surface of the inner wall of the housing  44 . In addition, when the ice  70  grown on the surface of the freezing pipe  52  is detached by heat medium, unfrozen silver chloride colloidal water is scattered to the periphery, and scattered to the top surface of the inner wall of the ice stocker  46  and the surface of the inner wall of the housing  44 , which contributes to the sterilization of the surfaces thereof. 
     In the above description, the electrolytic apparatus  64  is attached to the supply pipe  58 . However, the electrolytic apparatus  64  can be attached to any position of the water supply pipe  54  and the supply pipe  58  without being limited thereto. Furthermore, the electrolytic apparatus  64  may be attached to a plurality of positions. 
     A wall material in the housing  44  of the ice making apparatus  42 , and inner and outer wall surfaces of the water spray tank  50  and the ice making water tank  48  are preferably an antibacterial material. 
     REFERENCE SIGNS LIST 
     
         
           2 ,  12 ,  22 ,  32 ,  64 : electrolytic apparatus 
           4 ,  14 ,  24 ,  34 : electrolytic bath 
           6 ,  16 ,  36 : electrolytic raw water supply pipe 
           8 ,  18 ,  38 : electrolyzed water extraction pipe 
           16   t ,  36   t : electrolytic raw water supply main pipe 
           16   a ,  16   b ,  36   a ,  36   b  electrolytic raw water supply branch pipe 
           18   t : electrolyzed water extraction main pipe 
           18   a ,  18   b : electrolyzed water extraction branch pipe 
           26 : communicating pipe that connects a space having an electrode pair of the anode (I)—the cathode (II) and a space having an electrode pair of the cathode (II)—the anode (III) 
           28   a ,  38   a : connecting pipe of a space having an electrode pair of the anode (I)—the cathode (II) 
           28   b ,  38   b : connecting pipe of a space having an electrode pair of the cathode (II)—the anode (III) 
         I: anode of a silver electrode 
         II: cathode of an inert electrode 
         III: anode of an inert electrode 
         PI: wiring of the anode (I) 
         NIIa, NIIb: wiring of the cathode (II) 
         PIII: wiring of the anode (III) 
         G, Ga, Gb: arrow indicating a flow direction of electrolyzed water 
         R, Ra, Rb: arrow indicating a flow direction of electrolytic raw water 
           42 : ice making apparatus 
           44 : ice making apparatus housing 
           46 : ice stocker 
           48 : ice making water tank 
           50 : water spray tank 
           51 : through-hole 
           52 : freezing pipe 
           54 : water supply pipe 
           56 : water supply pump 
           58 : ice making water supply pipe 
           60 : refrigerant supplying means 
           62 : heat medium supplying means 
           66 : faucet 
           68 : water supply electromagnetic valve 
           70 : ice

Technology Classification (CPC): 2