Electrolyzing apparatus and electrolyzing method for electrolyzing flowing water containing chlorine ions

• US 5,954,939 A
• Filed: 08/05/1997
• Issued: 09/21/1999
• Est. Priority Date: 05/31/1994
• Status: Expired due to Term

• Current Assignee: Toto Limited
• Original Assignee: Toto Limited
• Inventors: Hayakawa, Makoto, Kiyohara, Masakatsu, Shono, Nobuhiro, Tabata, Kenji, Kanekuni, Nobuhiko, Kono, Shuhei
• Primary Examiner(s): Phasge, Arun S.
• Application Number:
  US08/906,259
• Time in Patent Office: 777 Days
• Field of Search: 205/742, 205/759, 204/228, 204/275, 204/278
• US Class Current: 205/742
• CPC Class Codes: C02F 1/46104 Devices therefor; Their operating or servicing
• CPC Class Codes: C02F 1/46109 Electrodes
• CPC Class Codes: C02F 1/4674 with halogen or compound of halogens, e.g. chlorine, bromine
• CPC Class Codes: C02F 2001/46133 characterised by the material
• CPC Class Codes: C02F 2001/46142 Catalytic coating
• CPC Class Codes: C02F 2201/4611 Fluid flow
• CPC Class Codes: C02F 2201/4613 Inversing polarity
• CPC Class Codes: C02F 2201/46145 Fluid flow
• CPC Class Codes: C02F 2201/46155 Heating or cooling
• CPC Class Codes: C02F 2201/4618 Supplying or removing reactants or electrolyte
• CPC Class Codes: C02F 2303/04 Disinfection

Abstract

An electrolyzing apparatus for flowing water containing chlorine ions has an electrolytic cell provided with at least one pair of electrodes, a passage formed between the electrodes, an inlet port and an outlet port communicating the passage, and a power supply for applying voltage across the electrodes.

Claims

1. An electrolyzing apparatus for producing water having bactericidal activity from flowing city water, well water, or industrial water, without adding chlorine compounds to the flowing eater, comprising:

non-barrier electrolytic cell;

at least two electrode plates separated by a distance of greater than or equal 0.2 mm and less than 0.5 mm, disposed within the cell and defining a passage therebetween;

a voltage sources connected to the electrode plates for supplying a voltage across the electrode plates at a current density of more than 500 A/m² and less than 1100 A/m² ;

an inlet port communicating with the passage for supplying flowing city water, well water, or industrial water to the passage, without adding electrolytes to the flowing water; and

an outlet port communicating with the passage for supplying water having bactericidal activity comprising electrolyzed flowing water from the passage without recirculation through said passage;

wherein one of said electrode plates is a positive electrode, another of said electrode plates is a negative electrode and at least the positive electrode is a chlorine-generating electrode, and

wherein said passage defined between the electrode plates has a cross-sectional area adjacent said outlet port 1.01 times or greater than a cross-sectional area of said passage adjacent said inlet port.

2. An electrolyzing apparatus according to claim 1, wherein said chlorine generating-electrode comprises a conductive material plate coated with a layer of chlorine-generating catalyst comprising platinum and iridium in an amount wherein the mole ratio of platinum to the sum of platinum and iridium is more than or equal to 70%.

3. An electrolyzing apparatus according to claim 2, wherein the thickness of said layer of chlorine-generating catalyst is greater than or equal to 0.1 μ

m and less than or equal to 1.0 μ

m.

4. An electrolyzing apparatus according to claim 1, wherein said chlorine-generating electrode comprises a conductive material plate coated with a layer of chlorine-generating catalyst comprising platinum, iridium and tantalum in an amount wherein the ratio of tantalum to the sum of platinum, iridium and tantalum is less than 30 weight %.

5. An electrolyzing apparatus according to claim 4, wherein the thickness of said layer of chlorine-generating catalyst is greater than or equal to 0.1 μ

m and less than or equal to 1.0 μ

m.

6. An electrolyzing apparatus according to claim 1, further comprising a plurality of spacers for separating said electrode plates and wherein said spacers comprise a material selected from polytetrafluoroethylene, polypropylene hexafluoride, trifluoroethylene, trifluorochloroethylene, tetrafluorosilane, and siloxane fluoride.

7. An electrolysing apparatus according to claim 1, further comprising a plurality of spacers for separating said electrode plates, wherein said spacers comprise a material containing a tetrafluoro radical.

8. An electrolyzing apparatus according to claim 1, wherein said electrode plates are coated with a non-conductive material at a portion adjacent said outlet port.

9. An electrolyzing apparatus according to claim 1, wherein said electrode plates are coated with a non-conductive material at a portion adjacent said outlet port.

10. A method for producing water having bactericidal activity by electrolyzing flowing city water, well water, or industrial water, without adding chlorine compounds to the flowing water, using an electrolyzing apparatus comprising:

a non-barrier electrolytic cell;

at least two electrode plates separated by a distance of greater than or equal to 0.2 mm and less than 0.5 mm, disposed within the cell and defining a passage therebetween;

a voltage source connected to the electrode plates for supplying a voltage across the electrode plates;

an inlet port communicating with the passage for supplying flowing city water, well water, or industrial water without adding salt to the flowing water; and

an outlet port communicating with the passage for supplying water having bactericidal activity comprising electrolyzed flowing water from the passage without recirculation through the passage;

wherein one of solid electrode plates is a positive electrode, another of said electrode plates is a negative electrode, and at least the positive electrode is a chlorine-generating electrode; and

wherein said passage defined between the electrode plates has a cross-sectional area adjacent said outlet port 1.01 times or greater than a cross-sectional area of said passage adjacent said inlet port,

said method comprising the steps of;

(1) supplying flowing city water, well water, or industrial water into the inlet port without adding electrolytes;

(2) applying voltage across said electrode plates at a current density of more than 500 A/m² and less than 1100 A/m² ; and

(3) electrolyzing the flowing water to produce water having bactericidal activity, and

(4) supplying the water having bactericidal activity from the outlet port without recirculating the water having bactericidal activity through the passage.

11. A method of claim 10, wherein said step of supplying flowing city water is continued until a prescribed length of time after said step of electrolyzing has stopped.

12. A method of claim 10, further comprising the step of reversing the polarity of said voltage once per 10 or so repetitions of electrolysis of said flowing water.

13. A method of claim 10, wherein said step of electrolyzing is carried out at a water temperature of more than room temperature and less than 50°

C.

14. An electrolysing apparatus according to claim 10, further comprising a plurality of spacers for separating said electrode plates, wherein said spacers comprise a material containing a tetrafluoro radical.

15. An electrolyzing apparatus according to claim 14, wherein said electrode plates are coated with a non-conductive material at a portion adjacent said outlet port.

16. An electrolyzing apparatus according to claim 10, wherein said electrode plates are coated with a non-conductive material at a portion adjacent said outlet port.

17. An electrolyzing apparatus for producing water having bactericidal activity from flowing city water, well water, or industrial water, without adding chlorine compounds to the flowing water, comprising:

a non-barrier electrolytic cell;

at least two electrode plates separated by a distance greater than or equal to 0.2 mm and less than 0.5 mm, disposed within the cell and defining a passage therebetween;

a voltage source connected to the electrode plates for supplying a voltage across the electrode plates at a current density of more than 500 A/m² and less than 1100 A/m² ;

an inlet port communicating with the passage for supplying flowing city water, well water, or industrial water to the passage, without adding electrolytes to the flowing water; and

an outlet port communicating with the passage for supplying water having bactericidal activity comprising electrolyzed flowing water from the passage without recirculation through said passage;

wherein one of said electrode plates is a positive electrode, another of said electrode plates is a negative electrode and at least the positive electrode is a chlorine-generating electrode, and

wherein said electrode plates are coated with a non-conductive material at a portion adjacent said inlet port and at a portion adjacent said outlet port.

18. An electrolysing apparatus according to claim 17, further comprising a plurality of spacers for separating said electrode plates, wherein said spacers comprise a material containing a tetrafluoro radical.

19. An electrolysing apparatus according to claim 18, wherein said passage defined between the electrode plates has a cross-sectional area adjacent said outlet port 1.01 times or greater than a cross sectional area of said passage adjacent said inlet port.

20. An electrolysing apparatus according to claim 17, wherein said passage defined between the electrode plates has a cross-sectional area adjacent said outlet port 1.01 times or greater than a cross sectional area of said passage adjacent said inlet port.

21. A method for producing water having bactericidal activity by electrolyzing flowing city water, well water, or industrial water containing a very small amount of chlorine ions, without adding electrolytes to the flowing water, using an electrolyzing apparatus comprising:

a non-barrier electrolytic cell;

at least two electrode plates separated by a distance of greater than or equal to 0.2 mm and less than 0.5 mm, disposed within the cell and defining a passage therebetween;

a voltage source connected to the electrode plates for supplying a voltage across the electrode plates;

an inlet port communicating with the passage for supplying flowing city water, well water, or industrial water without adding salt to the flowing water; and

an outlet port communicating with the passage for supplying water having bactericidal activity comprising electrolyzed flowing water from the passage without recirculation through the passage; and

wherein one of said electrode plates is a positive electrode, another of said electrode plates is a negative electrode, and at least the positive electrode is a chlorine-generating electrode, and

wherein said electrode plates are coated with a non-conductive material at a portion adjacent said inlet port and at a portion adjacent said outlet port,

said method comprising the steps of;

(1) supplying flowing city water, well water, or industrial water into the inlet port without adding electrolytes;

(2) applying voltage across said electrode plates at a current density of more than 500 A/m² and less than 1100 A/m² ; and

(3) electrolyzing the flowing water to produce water having bactericidal activity, and supplying the water having bactericidal activity from the outlet port without recirculating the water having bactericidal activity through the passage.

22. An electrolysing apparatus according to claim 21, further comprising a plurality of spacers for separating said electrode plates, wherein said spacers comprise a material containing a tetrafluoro radical.

23. An electrolysing apparatus according to claim 22, wherein said passage defined between the electrode plates has a cross-sectional area adjacent said outlet port 1.01 times or greater than a cross sectional area of said passage adjacent said inlet port.

24. An electrolysing apparatus according to claim 21, wherein said passage defined between the electrode plates has a cross-sectional area adjacent said outlet port 1.01 times or greater than a cross sectional area of said passage adjacent said inlet port.