U.S. patent application number 15/062619 was filed with the patent office on 2016-06-30 for electrolytic device and electrode.
This patent application is currently assigned to Kabushiki Kaisha Toshiba. The applicant listed for this patent is Kabushiki Kaisha Toshiba. Invention is credited to Wu Mei, Katsuyuki Naito, Hideo Oota, Norihiro Tomimatsu, Ryosuke Yagi, Masahiro YOKOTA, Norihiro Yoshinaga.
Application Number | 20160186337 15/062619 |
Document ID | / |
Family ID | 55533147 |
Filed Date | 2016-06-30 |
United States Patent
Application |
20160186337 |
Kind Code |
A1 |
YOKOTA; Masahiro ; et
al. |
June 30, 2016 |
ELECTROLYTIC DEVICE AND ELECTRODE
Abstract
According to one embodiment, an electrolytic device includes an
electrolytic cell including a first electrode, a second electrode
opposing the first electrode and a diaphragm provided between the
first electrode and the second electrode. The first electrode is
formed of a plate including a first surface opposing the diaphragm,
a second surface located on an opposite side to the diaphragm, and
first recess portions formed in the first surface with a first
pattern. The first recess portions include a bottom surface apart
from the first surface and through-holes opening to the second
surface of the first electrode and to a part of the bottom
surface.
Inventors: |
YOKOTA; Masahiro; (Fukaya,
JP) ; Oota; Hideo; (Tokyo, JP) ; Naito;
Katsuyuki; (Tokyo, JP) ; Yoshinaga; Norihiro;
(Kawasaki, JP) ; Mei; Wu; (Yokohama, JP) ;
Tomimatsu; Norihiro; (Mitaka, JP) ; Yagi;
Ryosuke; (Yokohama, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Kabushiki Kaisha Toshiba |
Minato-ku |
|
JP |
|
|
Assignee: |
Kabushiki Kaisha Toshiba
Minato-ku
JP
|
Family ID: |
55533147 |
Appl. No.: |
15/062619 |
Filed: |
March 7, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/JP2015/075626 |
Sep 9, 2015 |
|
|
|
15062619 |
|
|
|
|
Current U.S.
Class: |
204/252 ;
204/284 |
Current CPC
Class: |
C02F 2001/4619 20130101;
C02F 2001/46157 20130101; C25B 9/08 20130101; C02F 1/46109
20130101; C02F 1/4672 20130101; C25B 11/03 20130101; C02F
2201/46115 20130101; C02F 1/4674 20130101 |
International
Class: |
C25B 11/03 20060101
C25B011/03; C25B 9/08 20060101 C25B009/08 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 19, 2014 |
JP |
2014-191565 |
Claims
1. An electrolytic device comprising: an electrolytic cell
comprising a first electrode, a second electrode opposing the first
electrode and at least one diaphragm provided between the first
electrode and the second electrode, wherein the first electrode is
formed of a plate comprising a first surface opposing the
diaphragm, a second surface located on an opposite side to the
diaphragm, and first recess portions formed in the first surface
with a first pattern, the first recess portions include a bottom
surface apart from the first surface and through-holes each opening
to the second surface of the first electrode and to a part of the
bottom surface.
2. The electrolytic device of claim 1, wherein an area of the first
recess portions opened in the first surface of the first electrode
is 60% or larger than an area of the first surface.
3. The electrolytic device of claim 1, wherein an open aperture
ratio of the through-holes is 30% or less of the area of the first
surface of the first electrode.
4. The electrolytic device of claim 1, wherein an open area ratio
of the through-holes with respect to an area of the entire first
surface is a half or less, of an opening area ratio of the first
recess portions with respect to the area of the entire first
surface.
5. The electrolytic device of claim 1, wherein a depth of the first
recess portions is less than a half of a thickness of the first
electrode.
6. The electrolytic device of claim 5, wherein the depth of the
first recess portions is within 0.5 mm.
7. The electrolytic device of claim 1, wherein each of the first
recess portion includes a plurality of through-holes each opening
to the second surface and to a part of the bottom surface of the
first recess portion.
8. The electrolytic device of claim 1, wherein the first electrode
comprises second recess portion formed in the second surface with a
second pattern different from the first pattern, and a plurality of
parts of each second recess portion communicate with a respective
one of the first recess portions to form the plurality of
through-holes.
9. The electrolytic device of claim 8, wherein the first recess
portions extend in a first direction, respectively, and the second
recess portions open to the second surface and include an opening
dimension in the first direction, greater than a width of the first
recess portions, and a length of the first recess portions in the
first direction is longer than a width of the second recess
portions in the first direction, and a plurality of the first
recess portions communicate with a respective one of the second
recess portions to form the through-holes.
10. The electrolytic device of claim 9, wherein the first recess
portions are arranged in a width direction thereof at a first
pitch, and the second recess portions are arranged in a width
direction thereof at a second pitch greater than the first
pitch.
11. The electrolytic device of claim 10, wherein the first pitch of
the first recess portions is 0.8 mm or less.
12. The electrolytic device of claim 10, wherein the second pitch
of the second recess portions is 1 mm or greater.
13. The electrolytic device of claim 10, wherein a value obtained
by subtracting the opening width W1 of the first recess portions
from an arrangement pitch P1 of the first recess portions is 0.3 mm
or less.
14. The electrolytic device of claim 9, wherein a depth of the
second recess portions is greater than a half of the thickness of
the first electrode.
15. The electrolytic device of claim 9, wherein the second recess
portions extend in a second direction different from the first
direction.
16. The electrolytic device of claim 15, wherein a plurality of the
second recess portions communicate with a respective one of the
first recess portions to form respective ones of the
through-holes.
17. The electrolytic device of claim 14, wherein the first recess
portions extend continuously in the first direction from one end to
an other end of an effective region of the first electrode and the
second recess portions extend continuously in the second direction
from one end to the other end of the effective region of the first
electrode.
18. The electrolytic devices of claim 17, wherein the first recess
portions and the second recess portions extend linearly.
19. The electrolytic device of claim 17, wherein each of the first
recess portions is divided into plurality with gaps formed in the
first direction.
20. The electrolytic device of claim 18, wherein the second recess
portions are each divided into plurality with gaps formed in the
second direction.
21. The electrolytic device of claim 9, wherein the second recess
portions are constituted by through-holes penetrating the first
electrode.
22. The electrolytic device of claim 1, wherein the first recess
portions include a plurality of third recess portions which make
each adjacent pair of the first recess portions to communicate with
each other.
23. The electrolytic device of claim 1, wherein the first electrode
comprises a catalytic layer formed on the first recess portions
except for the first surface.
24. An electrode for use in an electrolytic device, formed in a
plate-shape, the electrode comprising: a first surface opposing a
diaphragm; a second surface located on an opposite side to the
first surface; and first recess portions formed in the first
surface with a first pattern; wherein the first recess portions
include a bottom surface apart from the first surface and
through-holes each opening to the second surface and to a part of
the bottom surface.
25. The electrode of claim 24, wherein an area of the first recess
portions opened in the first surface is 60% or larger than an area
of the first surface.
26. The electrode of claim 24, wherein an open aperture ratio of
the through-holes is 30% or less of an area of the first
surface.
27. The electrode of claim 24, wherein an open area ratio of the
through-holes with respect to an area of the entire first surface
is a half or less, of an opening area ratio of the first recess
portions with respect to the area of the entire first surface.
28. The electrode of claim 24, wherein a depth of the first recess
portions is less than a half of a thickness of the electrode.
29. The electrode of claim 28, wherein the depth of the first
recess portions is within 0.5 mm.
30. The electrode of claim 24, further comprising second recess
portions formed in the second surface with a second pattern
different from the first pattern, a plurality of locations of the
second recess portions communicate with the first recess portions
to form the through-holes.
31. The electrode of claim 24, wherein the first recess portions
open to the first surface and extend in a first direction, and the
second recess portions open to the second surface and having an
opening length greater than a width of the first recess portions in
a second direction crossing the first direction, and a length of
the first recess portion in the first direction is greater than a
width of the second recess portions in the first direction and a
plurality of the first recess portions are communicated with a
respective of one of the second recess portions to form the
through-holes.
32. The electrode of claim 24, wherein the first recess portions
include a plurality of third recess portions which make each
adjacent pair of the first recess portions to communicate with each
other.
33. The electrode of claim 24, further comprising a catalytic layer
formed on the first recess portions except for the first surface.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation application of PCT
Application No. PCT/JP2015/075626, filed Sep. 9, 2015 and based
upon and claiming the benefit of priority from Japanese Patent
Application No. 2014-191565, filed Sep. 19, 2014, the entire
contents of all of which are incorporated herein by reference.
FIELD
[0002] Embodiments described herein relate generally to an
electrolytic device and an electrode used for the electrolytic
device.
BACKGROUND
[0003] As an electrolytic device, an electrolyzed-water production
device for producing ionized alkaline water, ozone water, aqueous
hypochlorous acid or the like is conventionally known. As the
electrolyzed-water production device, a device comprising a
three-chamber electrolytic tank (electrolytic cell) has been
proposed. The three-chamber cell includes an electrolytic container
divided into three chambers, that is, an anode chamber, an
intermediate chamber and a cathode chamber by diaphragms. In such
an electrolytic device, for example, salt water is introduced into
the intermediate chamber, and water is introduced into the cathode
chamber and the anode chamber on the right and left sides. Thus,
the salt water in the intermediate chamber is electrolyzed by the
anode and the cathode to produce aqueous hypochlorous acid from
gaseous chlorine produced in the anode chamber and sodium hydroxide
solution in the cathode chamber. Hypochlorous acid thus produced
can be utilized as sterilizing solution and sodium hydroxide
solution as a cleaning solution.
[0004] However, an electrolytic device having such a three-chamber
cell involves reactions in a complicated way around the anode,
which proceed from chlorine ions to gaseous chloride and then to
hypochlorous acid. Here, if the reaction system does not take place
appropriately, competitive gaseous oxygen is produced and thus the
productivity of hypochlorous acid is reduced. Further, gaseous
chloride and hypochlorous acid produced here are strong oxidizers,
which may cause deterioration of diaphragms.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 is a block diagram schematically showing an
electrolytic device according to a first embodiment.
[0006] FIG. 2 is an exploded perspective view showing an
electrolytic cell of the electrolytic device according to the first
embodiment.
[0007] FIG. 3 is a sectional view of the electrolytic cell.
[0008] FIG. 4 is an expanded perspective view showing a first
electrode and an anode cover of the electrolytic cell.
[0009] FIG. 5 is a perspective view showing a first surface side of
the first electrode.
[0010] FIG. 6 is a perspective view showing a second surface side
of the first electrode.
[0011] FIG. 7 is a partially expanded perspective view showing the
first electrode.
[0012] FIG. 8 is a plan view of the first electrode as viewed from
the first surface side.
[0013] FIG. 9 is a sectional view of the first electrode and an
anion-exchange membrane, taken along line A-A of FIG. 8.
[0014] FIG. 10 is a sectional view of the first electrode and the
anion-exchange membrane, taken along line B-B of FIG. 8.
[0015] FIG. 11 is a partially expanded perspective view showing a
first electrode of an electrolytic device according to a first
modification.
[0016] FIG. 12 is a plan view of the first electrode according to
the first modification as viewed from the first surface side.
[0017] FIG. 13 is a sectional view of the first electrode and an
anion-exchange membrane, taken along line C-C of FIG. 12.
[0018] FIG. 14 is a sectional view of the first electrode and an
anion-exchange membrane, taken along line D-D of FIG. 12.
[0019] FIG. 15 is a partially expanded perspective view showing a
first electrode of an electrolytic device according to a second
modification.
[0020] FIG. 16 is a plan view of the first electrode according to
the second modification as viewed from the first surface side.
[0021] FIG. 17 is a sectional view of the first electrode and an
anion-exchange membrane, taken along line E-E of FIG. 16.
[0022] FIG. 18 is a sectional view of the first electrode and an
anion-exchange membrane, taken along line F-F of FIG. 16.
[0023] FIG. 19 is a partially expanded perspective view showing a
first electrode of an electrolytic device according to a third
modification.
[0024] FIG. 20 is a plan view of the first electrode according to
the third modification as viewed from the first surface side.
[0025] FIG. 21 is a sectional view of the first electrode and an
anion-exchange membrane, taken along line G-G of FIG. 20.
[0026] FIG. 22 is a sectional view of the first electrode and an
anion-exchange membrane, taken along line H-H of FIG. 20.
[0027] FIG. 23 is a partially expanded perspective view showing a
first electrode of an electrolytic device according to a fourth
modification.
[0028] FIG. 24 is a partially expanded perspective view showing a
first electrode of an electrolytic device according to a fifth
modification.
[0029] FIG. 25 is a partially expanded perspective view showing a
first electrode of an electrolytic device according to a sixth
modification.
[0030] FIG. 26 is a partially expanded perspective view showing a
first electrode of an electrolytic device according to a seventh
modification.
[0031] FIG. 27 is a plan view of the first electrode according to
the seventh modification as viewed from the first surface side.
[0032] FIG. 28 is a sectional view of the first electrode and an
anion-exchange membrane, taken along line I-I of FIG. 27.
[0033] FIG. 29 is a partially expanded perspective view showing a
first electrode of an electrolytic device according to an eighth
modification.
[0034] FIG. 30 is a plan view of the first electrode according to
the eighth modification as viewed from the first surface side.
[0035] FIG. 31 is a sectional view of the first electrode and an
anion-exchange membrane, taken along line J-J of FIG. 30.
DETAILED DESCRIPTION
[0036] Various embodiments will be described below with reference
to the accompanying drawings. In general, according to one
embodiment, an electrolytic device comprises an electrolytic cell
comprising a first electrode, a second electrode opposing the first
electrode and at least one diaphragm provided between the first
electrode and the second electrode. The first electrode is formed
of a plate comprising a first surface opposing the diaphragm, a
second surface located on an opposite side to the diaphragm, and
first recess portions formed in the first surface with a first
pattern. The first recess portions include a bottom surface apart
from the first surface and through-holes each opening to the second
surface of the first electrode and to a part of the bottom
surface.
[0037] Throughout the embodiments, common structural members are
designated by the same reference symbols, and the explanation
therefor will not be repeated. Further, the drawings are schematic
diagrams designed to assist the reader to understand the
embodiments easily. Thus, there may be sections where the shape,
dimensions, ratio, etc. are different from those of the actual
devices, but they can be re-designed as needed with reference to
the following explanations and publicly known techniques.
First Embodiment
[0038] FIG. 1 is a diagram briefly showing an electrolytic device
according to the first embodiment. In this embodiment, the
electrolytic device 10 is constituted as an electrolysis water
production device. The electrolytic device 10 comprises, as shown
in FIG. 1, a three-chamber electrolytic cell 11. The electrolytic
cell 11 is formed into a flat rectangle box, inside of which is
divided by an anion-exchange membrane 16 as a first diaphragm and a
cation-exchange membrane 18 as a second diaphragm into an
intermediate chamber 15a, and also an anode chamber 15b and a
cathode chamber 15c located on both sides of the intermediate
chamber 15a. A first electrode (anode) 14 is provided in the anode
chamber 15b so as to oppose the anion-exchange membrane 16. A
second electrode (cathode) 20 is provided in the cathode chamber
15c so as to oppose the cation-exchange membrane 18.
[0039] The electrolytic device 10 comprises an electrolyte supplier
19 which supplies an electrolyte, for example, saturated salt
water, to the intermediate chamber 15a of the electrolytic cell 11,
a water supplier 21 which supplies a solution to be electrolyzed,
for example, water, to the anode chamber 15b and the cathode
chamber 15c and a power supply 23 that applies positive and
negative voltages respectively to the first and second electrodes
14 and 20.
[0040] The electrolyte supplier 19 comprises a salt water tank 25
to produce saturated salt water, a supply pipe 19a which conveys
saturated salt water from the salt water tank 25 to a lower portion
of the intermediate chamber 15a, a liquid feed pump 29 provided in
the supply pipe 19a and a drainage pipe 19b which sends the
electrolyte which has flowed through the inside of the intermediate
chamber 15a from an upper portion of the intermediate chamber 15a
to the salt water tank 25.
[0041] The water supplier 21 comprises a water supply source (not
shown) which supplies water, a water supply pipe 21a which guides
water to lower portions of the anode chamber 15b and the cathode
chamber 15c from the water supply source, a first drainage pipe 21b
to discharge the water which has flowed through the anode chamber
15b from an upper portion of the anode chamber 15b, a second
drainage pipe 21c to discharge the water which has flowed through
the cathode chamber 15c from an upper portion of the cathode
chamber 15c and a gas-liquid separator 27 provided in the second
drainage pipe 21c.
[0042] The operation of the electrolytic device 10 configured as
described above, which actually electrolyzes salt water to produce
an acidic solution (aqueous hypochlorous acid and hydrochloric
acid) and alkaline water (sodium hydroxide) will now be
described.
[0043] As shown in FIG. 1, the liquid feed pump 29 is operated to
supply saturated salt water to the intermediate chamber 15a of the
electrolytic cell 11, and water to the anode chamber 15b and the
cathode chamber 15c. At the same time, a positive voltage and a
negative voltage are applied to the first electrode 14 and the
second electrode 20, respectively, from the power supply 23. Sodium
ions electrolytically dissociated in the salt water which has
flowed into the intermediate chamber 15a are attracted towards the
second electrode 20, pass through the cation-exchange membrane 18
and flow into the cathode chamber 15c. Then, in the cathode chamber
15c, water is electrolyzed by the second electrode 20 and gaseous
hydrogen and an aqueous solution of sodium hydroxide are obtained.
The aqueous solution of sodium hydroxide and gaseous hydrogen thus
produced flow out of the cathode chamber 15c into the second
drainage pipe 21c, and are then separated into an aqueous solution
of sodium hydroxide and gaseous hydrogen by the gas-liquid
separator 27. The aqueous solution of sodium hydroxide (alkaline
water) is discharged through the second drainage pipe 21c.
[0044] Meanwhile, chlorine ions electrolytically dissociated in the
salt water in the intermediate chamber 15a are attracted towards
the first electrode 14, pass through the anion-exchange membrane 16
and flow into the anode chamber 15b. Then, the chlorine ions give
electrons to the anode with the first electrode 14 to produce
gaseous chlorine. After that, the gaseous chlorine reacts with
water in the anode chamber 15b to produce hypochlorous acid and
hydrochloric acid. The acidic solution thus produced (aqueous
hypochlorous acid and hydrochloric acid) is discharged from the
anode chamber 15b through the first liquid drainage pipe 21b.
[0045] Next, the structure of the electrolytic cell 11 will now be
described in more detail. FIG. 2 is an exploded perspective view of
the electrolytic cell, and FIG. 3 is a sectional view thereof. As
shown in FIGS. 2 and 3, the electrolytic cell 11 comprises an
intermediate frame 22 of a rectangular frame shape, which functions
as a diaphragm, an anode cover (first cover member) 24 of a
rectangular plate shape having outer dimensions substantially equal
to those of the intermediate frame 22, which covers one side
surface of the intermediate frame, and a cathode cover (second
cover member) 26 of a rectangular plate shape having outer
dimensions substantially equal to those of the intermediate frame
22, which covers the other side surface of the intermediate
frame.
[0046] The anion-exchange membrane 16 is disposed between the
intermediate frame 22 and the anode cover 24, as a first diaphragm
to separate the intermediate chamber 15a and the anode chamber 15b
from each other, and the first electrode (anode plate) 14 is
disposed near the anion-exchange membrane 16 in the anode chamber
15b. The cation exchange membrane 18 is disposed between the
intermediate frame 22 and the cathode cover 26, as a second
diaphragm to separate the intermediate chamber 15a and the cathode
chamber 15c from each other, and the second electrode (cathode) 20
is disposed near the cation-exchange membrane 18 in the cathode
chamber 15c.
[0047] A first inlet 34 communicating with the intermediate chamber
15a is formed in a lower end of the intermediate frame 22 and a
first outlet 36 communicating with the intermediate chamber 15a is
provided in an upper end thereof. The supply pipe 19a and the
drainage pipe 19b are connected to the first inlet 34 and the first
outlet 36, respectively.
[0048] As shown in FIGS. 2 to 4, a plurality of linear ribs 33 are
provided on an inner surface of the anode cover 24, to extend in,
for example, the vertical direction (the second direction Y). The
ribs 33 are arranged parallel to each other while keeping a
predetermined gap between adjacent ones. Between each adjacent pair
of the ribs 33, a circulation groove 32a is provided to extend in
the vertical direction. Further, a pair of upper and lower side
grooves by which ends of each circulation groove 32a communicate
are formed in the inner surface of the anode cover 24. The anode
chamber 15b is defined by the circulation grooves 32a, the side
grooves and the anion-exchange membrane 16. In addition, the
circulation grooves 32a and the side grooves form flow paths for
water.
[0049] A second inlet 37 communicating with the lower end of the
circulation grooves 32a is formed in a lower portion of the anode
cover 24, and a second outlet 38 communicating with the upper end
of the circulation grooves 32a is formed in an upper portion of the
anode cover 24. The supply pipe 21a and the first drainage pipe 21b
are connected to the second inlet 37 and the second outlet 38,
respectively.
[0050] A plurality of ribs 35, circulation grooves 32b, and side
grooves are each formed on an inner surface of the cathode cover 26
so as to extend in the perpendicular direction (the second
direction Y). The circulation grooves 32b, the side grooves and the
cation-exchange membrane 18 defines the cathode chamber 15c.
Further, the circulation grooves 32b and the side grooves form a
flow path for water to flow.
[0051] A third inlet 39 communicating with the lower end of the
circulation grooves 32b is formed in a lower portion of the cathode
cover 26, and a third outlet 41 communicating with the upper end of
the circulation grooves 32a is formed in an upper portion thereof.
The supply pipe 21a and the second drainage pipe 21c are connected
to the third inlet 39 and the third outlet 41, respectively.
[0052] As shown in FIGS. 2 and 3, frame-shaped sealing materials 40
for preventing leakage are disposed respectively between structural
components, that is, between the peripheral portion of the anode
cover 24 and the peripheral portion of the first electrode 14;
between the peripheral portions of the first electrode 14 and the
anion-exchange membrane 16 and the intermediate frame 22; between
the intermediate frame 22 and the peripheral portions of the second
electrode 20 and the cation-exchange membrane 18; and between the
peripheral portion of the second electrode 20 and the peripheral
portion of the cathode cover 26.
[0053] A plurality of fixing bolts 50 are inserted through the
peripheral portions of these structural components from, for
example, the anode cover 24 side and the tip portions project from
the cathode cover 26. A nut 52 is screwed into the tip portion of
each fixing bolt 50. With the fixing bolts 50 and the nuts 52 as
fastening components, the peripheral portions of the structural
components are fastened respectively with each other to maintain
the water tightness of the intermediate chamber 15a, the anode
chamber 15b and the cathode chamber 15c.
[0054] As shown in FIGS. 2 and 3, the anion-exchange membrane 16
and the cation-exchange membrane 18 are each formed into a thin
rectangular plate having an outer size substantially equal to that
of the intermediate frame 22 and a thickness of about 100 to 200
.mu.m. The anion-exchange membrane 16 and the cation-exchange
membrane 18 each have characteristics of passing only specific
ions. A plurality of through-holes through which the fixing bolts
50 are inserted are formed in the peripheral portions of the
anion-exchange membrane 16 and the cation-exchange membrane 18.
[0055] The anion-exchange membrane 16 is disposed to oppose one
surface side of the intermediate frame 22, and the peripheral
portion thereof is tightly attached to the intermediate frame 22
through the sealing material 40. Similarly, the cation-exchange
membrane 18 is disposed to oppose the other surface side of the
intermediate frame 22 and the peripheral portion thereof is tightly
attached to the intermediate frame 22 through the sealing material
40. Note that the first diaphragm and the second diaphragm may be
formed from not only an ion-exchange membrane but a porous membrane
having water permeability.
[0056] The first electrode 14 and the second electrode 20 are each
formed from a metal plate having a thickness of about 1 mm, formed
into a rectangular shape having an outer size substantially equal
to that of the intermediate frame 22. The first electrode 14 and
the second electrode 20 each have a central portion (effective
region) where micro-through-holes for passing liquid are formed,
and a peripheral portion in which a plurality of through-holes
through which fixing bolts 50 are inserted are formed. The first
electrode 14 includes a contact terminal 14b projecting from a side
edge thereof. Similarly, the second electrode 20 includes a contact
terminal 20b projecting from a side edge thereof.
[0057] The first electrode 14 is arranged to oppose to and be
tightly contact with the anion-exchange membrane 16. The second
electrode 20 is arranged to oppose to and be tightly contact with
the cation-exchange membrane 18.
[0058] Next, the structure of the first electrode (anode) 14 will
be described in detail as a typical example of the electrodes.
[0059] FIG. 4 is an expanded perspective view of the first
electrode and the anode cover. FIG. 5 is a perspective view of the
first surface side of the first electrode. FIG. 6 is a perspective
view of the second surface side of the first electrode. FIG. 7 is a
partially expanded perspective view of the first electrode. FIG. 8
is a plan view of the first electrode as viewed from the first
surface side. FIG. 9 is a sectional view of the first electrode and
the anion-exchange membrane, taken along line A-A of FIG. 8. FIG.
10 is a sectional view of the first electrode and the
anion-exchange membrane, taken along line B-B of FIG. 8.
[0060] As shown in FIG. 4 to FIG. 7, the first electrode 14 has,
for example, a porous, mesh structure in which a great number of
recesses and through-holes are made in a matrix 17 of a rectangular
metal plate. The matrix 17 includes a first surface 17a and a
second surface 17b opposing substantially parallel to the first
surface 17a. The distance between the first surface 17a and the
second surface 17b, that is, the plate board thickness T, is, for
example 0.8 mm. The first surface 17a opposes the first diaphragm
16 and the second surface 17b opposes the anode cover 24. The
matrix 17 may be made from a metal such as titanium.
[0061] In the first surface 17a of the matrix 17, a first recess R1
having a first pattern is formed over the entire surface. In the
second surface 17b of the matrix 17, a second recess R2 having a
second pattern different from the first pattern is formed over the
entire surface.
[0062] In this embodiment, the first recess R1 of the first pattern
comprises a plurality of thin linear first recess portions 42
formed in the first surface 17a of the matrix 17 and the first
recess portions 42 are each opened in the first surface 17a. Each
of the first recess portions 42 includes a bottom surface (bottom
portion) 42a which is apart from the first surface 17a, that is,
recessed from the first surface 17a by a predetermined depth. The
second recess R2 of the second pattern comprises a plurality of
thick or coarse linear second recess portions 44 formed in the
second surface 17b of the matrix 17 and the second recess portions
44 are each opened to the second surface 17b. The first recess
portions 42 and the second recess portions 44 are formed in the
entire rectangular effective region excluding the peripheral
portion of the matrix 17. A plurality of first recess portions 42
communicate with one second recess 44 and each of the communicating
portions forms a through-hole 46. Each of the through-holes 46
opens to a part of the bottom surface 42a of the first recess
portion 42 and opens to the second surface 17b of the matrix 17.
The entire surface of the first electrode 14 is covered with an
iridium oxide catalyst. The iridium oxide catalyst produces a lower
overvoltage in the gaseous chlorine production than in the
competitive gaseous oxygen production, and if there are a certain
number of chlorine ions around the anode, gaseous chlorine is
selectively produced.
[0063] As shown in FIGS. 4 to 10, in this embodiment, the first
recess portions 42 are each formed into straight lines extending in
the first direction X, for example, a horizontal direction. The
first recess portions 42 are arranged to be parallel to one
another. The first recess portions 42 are each formed to be longer
than an opening width W3 of the second recess portions 44, which
will be described later. In this embodiment, the first recess
portions 42 each extend continuously from one end to the other end
of the effective region of the first surface 17a (central region of
the rectangular shape, excluding the peripheral portion on the
first surface). An opening width W1 of the first recess portions 42
is, for example, 0.4 mm, a pitch P1 of the first recess portions 42
in the arranging direction Y is 0.5 mm, a depth D1 of the first
recesses 42 is less than a half of the thickness T of the matrix
17, more specifically, for example, 0.1 to 0.2 mm. In this
embodiment, the first recess portions 42 are each formed so as to
widen from the bottom portion (bottom surface 42a) side toward the
first surface 17a, more specifically, to have substantially a
trapezoidal shape in cross section. The both side surfaces which
define each first recess 42 extend while inclining with respect to
the first surface 17a. With this structure, some of the first
recess portions 42 communicate with a plurality of second recess
portions 44 by a through-width W2 of 0.2 mm.
[0064] In this embodiment, the second recess portions 44 on the
second surface 17b side are formed in a straight line extending in
a direction crossing the first direction X, that is, for example, a
second direction Y orthogonal to the direction X. The second recess
portions 44 are arranged to be parallel to each other. The second
recess portions 44 each extend from one end to the other end of the
effective region (central region of the rectangular shape,
excluding the peripheral portion on the second surface) of the
second surface 17b. An opening width W3 of the second recess
portions 44 is sufficiently larger than the opening width W1 of the
first recess portions 42, for example, 2.4 mm, a pitch P2 of the
second recess portions 44 in the arranging direction X is 3 mm, and
a depth D2 of the second recess portions 44 is greater than a half
of the thickness T of the matrix 17, more specifically, 0.6 to 0.7
mm. In this embodiment, the second recess portions 44 are each
formed so as to widen from the bottom side toward the second
surface 17b, more specifically, to have substantially a trapezoidal
shape in cross section. The both side surfaces which define each
second recess 44 42 extend while inclining with respect to the
second surface 17b. With this structure, the second recess portions
44 communicate with a plurality of first recess portions 42 by a
through-width W4 of 1.2 mm.
[0065] The first electrode 14 configured as above can be produced
by the following procedure, for example. That is, the first surface
17a and the second surface 17b of the matrix 17 are etched to be
partially cut out, thus forming the first recess R1 of the first
pattern and the second recess R2 of the second pattern. The
cross-sections of the first recess portions 42 and the second
recess portions 44 may be various shapes, more specifically, not
only a trapezoidal but also rectangular, semicircular, elliptical,
arc-like and the like. Further, the angle made by the first recess
portions 42 and the second recess portions 44 crossing therewith is
not limited to right-angles, but may be any other angles.
[0066] With the structure, the first recess portions 42 and the
second recess portions 44 of the first electrode 14 communicate
respectively with each other at intersections to form a great
number of through-holes 46. The first surface 17a opposing the
first diaphragm 16 includes the most, more specifically, 80% of the
surface opened by the first recess portions 42, and the area opened
and made to communicate is set as low as 16% of the surface area of
the electrode. Further, in consideration of the collection of
bubbles from the through-holes 46, the water flow is set in the
width direction (the second direction Y) of the through-holes 46.
As described, in this electrode, the matrix 17 is etched from both
sides, namely, the first and second surfaces 17a and 17b, and
therefore it is possible to change the open aperture ratio in each
surface. Thus, this electrode can exhibit a function which cannot
be attained with the conventional electrode having the same open
aperture ratio in both surfaces, manufactured by, for example, a
die cut process. It is preferable here that the open area ratio of
the through-holes 46 formed by the first recess portions 42 and the
second recess portions 44 communicating with each other with
respect to the entire area of the first surface 17a be no more than
a half of the open area ratio of the first recess portions 42 to
the entire area of the first surface.
[0067] Note that in this embodiment, the second electrode (cathode)
20 is similar in structure to the first electrode 14.
[0068] As shown in FIGS. 3 and 4, the first electrode 14 is
disposed in a direction where the extending direction Y of the
second recess portions 44 and the extending direction of the
circulation grooves (flow paths) 32a of the anode cover 24
substantially coincide with each other. The second surface 17b of
the first electrode 14 opposes the inner surface of the anode cover
24 and is in contact with the tip end surfaces of the ribs 33. With
this structure, water supplied to the anode chamber 15b flows along
the circulation grooves 32a and the second recess portions 44 of
the first electrode 14, that is, in a direction crossing the first
recess portions 42 of the first electrode 14.
[0069] Further, as shown in FIGS. 3, 9 and 10, the first surface
17a of the first electrode 14 opposes and is tightly attached to
the first diaphragm 16. Here, since the first recess portions 42
are formed in about 80% of the effective region of the first
surface 17a, the bottom surfaces 42a of the first recess portions
42 are apart from the first diaphragm 16 and the first surface of
the first electrode 14 by a depth of the first recess portion 42,
which is 0.1 to 0.2 mm. As shown in FIG. 10, the main reaction
occurs at the bottom surfaces (bottom portions) 42a of the first
recess portions 42, slightly apart from the first diaphragm 16, and
hypochlorous acid, which is a produce, is collected from the tiny
gaps made by the first recess portions 42 through the through-holes
46 into the anode chamber 15b. Thus, it is possible to achieve high
production efficiency and prevention of degradation of the
diaphragm both at the same time.
[0070] According to the electrolytic device 10 of the first
embodiment, which employs the first electrode 14 having the
above-described structure, an outstanding advantageous effect can
be obtained as compared to the case of employing a conventional
electrode formed by stamping (punching process) or expanding after
making nicks (expand/lath processing). In other words, a great
number of first recess portions 42 are formed in the first surface
17a which opposes the first diaphragm 16 of the first electrode 14
and therefore the first electrode 14 and the first diaphragm 16 can
be set apart from each other by a slight distance without providing
a separate member such as a spacer. With this structure, it is
possible to improve the high production efficiency and the
anti-degradation of the diaphragm both at the same time.
[0071] With the conventional stamping process, an electrode is
basically formed to include only through-holes made from the first
to second surfaces 17a and 17b with the same open area. Therefore,
if the first electrode 14 and the first diaphragm 16 are attached
tightly to each other, the main reaction occurs on the first
surface 17a which opposes the first diaphragm 16. Here, the first
surface is tightly attached to the first diaphragm, a problem may
arise, in which the diaphragm 16 is degraded by reaction products.
Further, when the first surface and the first diaphragm are tightly
attached, another problem may arise, in which products produced by
the electrolytic reaction cannot be collected, thus degrading the
efficiency.
[0072] In this embodiment, the first recess portions 42 (first
recess R1) are formed in the first surface 17a, which is the main
reaction field, at an area ratio of high as 80%. With this
structure, reaction products are quickly collected through a slight
gap D1 (first recess portion 42) and through-holes 46 into the
circulation grooves 32a, thereby making it possible to suppress
degradation of the first diaphragm 16.
[0073] It is ideal that the first recess portions 42 have an open
area occupying ratio as high as possible, but in practice, the
above-described effect can be sufficiently exhibited if they occupy
60% or more of the effective region of the first surface 17a.
Further, it is more effective if the pitch P1 of arrangement of the
first recess portions 42 is finer to collect the products from the
portions thereof which are in contact with the first diaphragm 16.
In practice, the effect can be sufficiently exhibited if the pitch
P1 is 0.8 mm or less. It is ideal that the depth D1 of the first
recess portions 42 is less as possible, but in practice, the
above-described effect can be sufficiently exhibited if it is 0.5
mm or less. Further, if the minimum width of the region in the
first surface 17a of the first electrode 14 is formed, is set to
0.3 mm or less, that is, the value obtained by subtracting the
opening width W1 of the first recess portions 42 from the
arrangement pitch P1 of the first recesses 42 is 0.3 mm or less, it
becomes easy to collect the substances produced by the electrolytic
reaction from the first surface 17a tightly attached to the
diaphragm. Thus, the above-described effect can be exhibited.
[0074] One of the functions of the second recess portions 44 of the
first electrode 14 is to form the through-holes 46 for collecting
the products from the first recess portions 42 formed shallow at
high precision to the anode chamber 15b side. Another function of
the second recess portions 44 is to collect the current
electrolyzed by the first recess portions 42 at lower resistance.
To achieve this, the second recess portions 44 are formed to be
coarse linear dent portions which cross the first recess portions
42. By crossing the first recess portions 42 and the second recess
portions 44 perpendicularly with each other, the intersections of
the first recess portions 42 and the respective second recess
portions 44 communicate with each other to extract hypochlorous
acid or the like, produced in the first recess portions 42 from the
through-holes 46 to the anode chamber 15b side. Note that the area
ratio of the through-holes 46 with respect to the area of the first
electrode 14 is set as low as 16%. This is because the region of
the first recess portions 42, lost by the through-holes 46 should
be made as small as possible. As the area of the through-holes 46
becomes larger, the number of chlorine ions lost by diffusion
through the through-holes 46 increases. For this reason, the area
of the through-holes 46 should desirably be set within 30% of the
area of the electrode.
[0075] Further, in this embodiment, the first recess portions 42
and the second recess portions 44 are formed into a linear shape,
whose longitudinal directions cross each other orthogonally. With
this structure, one first recess portion 42 communicate with a
plurality of second recess portions 44 to form a through-hole 46,
thereby improving the drainage of the first recess portions 42
better than the case where the first recess portions 42 and the
second recess portions 44 communicate with each other one to one.
That is, a plurality of through-holes 46 are provided in one second
recess 44 without making a dead end, thus forming such a structure
for reaction products, especially, air bubbles to easily pass
through. The linear second recess portions 44 are arranged to
intersect perpendicularly with the first recess portions 42 at a
coarse pitch so as to set the ratio of the area of the
through-holes to as low as 16% while keeping the ratio of the open
area of the first recesses 42 as high as 80%. Thus, the lowering of
the concentration, which is caused by the diffusion of the
electrolyte from the through-holes 46, can be prevented without the
first diaphragm 16 being degraded by the reaction products.
[0076] The second recess portions 44 are arranged at a coarse pitch
P2 of several millimeters, for example, 3 mm, so that the volume of
the matrix 17 remains at large and the current produced by
electrolysis can be supplied at lower resistance. Further, the
intensity of the electrode itself can be maintained. In practice,
the pitch P2 is set to 1 mm or more to obtain a sufficient feed
resistance.
[0077] As described above, according to the first embodiment, it is
possible to provide a long-life and efficient electrolytic device
and an electrode, in which degradation of the diaphragm can be
suppressed.
[0078] Next, the electrodes of electrolytic devices according to
various modifications will be described.
[0079] Note that in the modifications described below, the elements
which are identical to those of the first embodiment are denoted by
the same reference symbols, and parts different from those of the
first embodiment will be mainly described in detail.
[0080] (First Modification)
[0081] FIG. 11 is a partially expanded perspective view of the
first electrode according to the first modification. FIG. 12 is a
plan view of the first electrode as viewed from the first surface
side. FIG. 13 is a sectional view of the first electrode and the
anion-exchange membrane, taken along line C-C of FIG. 12. FIG. 14
is a sectional view of the first electrode and the anion-exchange
membrane, taken along line D-D of FIG. 12.
[0082] As shown in FIG. 11 or FIG. 14, according to the first
modification, the basic specification of the first electrode 14 is
the same as that of the first embodiment shown in FIGS. 4 to 10
except that the second recess portions 44 of the second recess
portions R2 are formed thin to have an arrangement pitch P2 of 3
mm, as in the first embodiment, but an opening width W3 of 1.6 mm
and a through-width W4 of 0.4 mm.
[0083] With the above-described structure, the area ratio of the
through-holes 46 is decreased to low as about 5%, thereby making it
possible to further suppress the chlorine ions having passed
through the first diaphragm 16 to diffuse in the circulation
grooves 32a. Thus, the chlorine ion concentration in the first
surface 17a of the first electrode 14 is increased to suppress the
production of gaseous oxygen, thereby improving the production
efficiency of acidic solution.
[0084] (Second Modification)
[0085] FIG. 15 is a partially expanded perspective view of the
first electrode according to the second modification. FIG. 16 is a
plan view of the first electrode as viewed from the first surface
side. FIG. 17 is a sectional view of the first electrode and the
anion-exchange membrane, taken along line E-E of FIG. 16. FIG. 18
is a sectional view of the first electrode and the anion-exchange
membrane, taken along line F-F of FIG. 16.
[0086] As shown in FIGS. 15 to 18, according to the second
modification, a plurality of second recess portions 44 which
constitute the second recess R2 formed in the second surface 17b of
the first electrode 14 each extend in the second direction Y which
intersects the first direction X perpendicularly, but are divided
into a plurality of sections without being continuous in the second
direction. In other words, the second recess portions 44 of each
row contain a plurality of segments of second recess portions 44
arranged in the second direction Y at a predetermined gap. The
length of each segment of the second recess portions 44 in the
second direction Y is equal to or greater than a total of widths of
two or more of the first recess portions 42. Further, the length of
the first recess portions 42 is greater than the width W3 of the
second recess portions 44. With this configuration, the
intersections of the first recess portions 42 and the second recess
portions 44 communicate with each other to form a plurality of
through-holes 46. A plurality of first recess portions 42
communicate with one segment of the second recess portions 44.
[0087] According to the second modification having the
above-described structure, the second recess portions 44 of each
row is divided into a plurality of segments so that wide linear
portions remain between adjacent pairs of the segments of each
second recess. With this structure, the mechanical strength is
improved in all plane directions of the first electrode 14, and
also the anisotropy of the feed resistance of the first electrode
can be relaxed.
[0088] Note that in the first embodiment described above, the
second recess portions 44 are formed concurrently with the
circulation grooves 32a, but the first electrode 14 may be placed
in the direction in which the second recess portions 44 intersect
perpendicularly with the circulation grooves 32a.
[0089] (Third Modification)
[0090] FIG. 19 is a partially expanded perspective view of the
first electrode according to the third modification. FIG. 20 is a
plan view of the first electrode as viewed from the first surface
side. FIG. 21 is a sectional view of the first electrode and the
anion-exchange membrane, taken along line G-G of FIG. 20. FIG. 22
is a sectional view of the first electrode and the anion-exchange
membrane, taken along line H-H of FIG. 20.
[0091] According to the third modification, the first electrode 14
comprises a large number of first recess portions 42 formed in the
first surface 17a, which constitute the first recess R1. The second
recesses formed in the second surface 17b of the first electrode 14
are formed from the through-holes 47. That is, the through-holes 47
are opened in the first surface 17a and the second surface 17b of
the matrix 17. The through-holes 47 each have, for example, a
circular shape whose diameter is larger than the width W1 of the
first recess portions 42. In other words, the opening length of the
through-holes 47 in the second direction Y is grater than the width
W1 of the first recess portions 42. A plurality of first recess
portions 42 communicate with one through-hole 47.
[0092] Since high precision is required, the first recess portions
42 of the first electrode 14 are formed by etching or
photolithography, but the through-holes 47 as the second recesses
are not so highly precise and may be formed by the conventional
punch process.
[0093] (Fourth Modification)
[0094] FIG. 23 is a partially expanded perspective view of the
first electrode according to the fourth modification. According to
the fourth modification, a plurality of first recess portions 42
which constitute the first recess R1 formed in the first surface
17a of the first electrode 14 each extend in the first direction X,
but are divided into a plurality of sections without being
continuous in this direction. In other words, the first recess
portions 42 of each row contain a plurality of segments of first
recess portions 42 arranged in the first direction X at a
predetermined gap. The length of each segment of the first recess
portions 42 is greater than the width W3 of the second recess
portions 44. With this configuration, the intersections of the
first recess portions 42 and the second recess portions 44
communicate with each other to form a plurality of through-holes
46. A plurality of segments of first recess portions 42 communicate
with a respective second recess portion 44.
[0095] According to the fourth modification having the
above-described structure, the first recess portions 42 of each row
is divided into a plurality of segments so that linear portions
remain between adjacent pairs of the segments of each first recess.
With this structure, the mechanical strength is improved in all
plane directions of the first electrode 14, and also the anisotropy
of the feed resistance of the first electrode can be relaxed.
[0096] (Fifth Modification)
[0097] FIG. 24 is a partially expanded perspective view of the
first electrode according to the fifth modification. The shape of
the first recess portions 42 formed in the first surface 17a of the
first electrode 14 is not limited to linear, but may be in some
other shape. According to the fifth modification, the first recess
portions 42 formed in the first surface 17a of the first electrode
14 are not linear, but extend along the direction X while being
bent at two or more locations.
[0098] (Sixth Modification)
[0099] FIG. 25 is a partially expanded perspective view of the
first electrode according to the fifth modification. According to
the fifth modification, the first recess portions 42 which formed
in the first surface 17a of the first electrode 14 and constitute
the first recess R1 extending along the first direction X to be
curved or waved at two or more locations.
[0100] (Seventh Modification)
[0101] FIG. 26 is a partially expanded perspective view showing the
first electrode according to the seventh modification. FIG. 27 is a
plan view of the first electrode as viewed from the first surface
side. FIG. 28 is a sectional view of the first electrode and the
anion-exchange membrane, taken along line I-I of FIG. 27.
[0102] As shown in FIGS. 26 to 28, according to the seventh
modification, the first recess R1 formed in the first surface 17a
of the first electrode 14 include a plurality of third recess
portions 45 in addition to the first recess portions 42. The third
recess portions 45 are formed by forming a notch in at least one
part of a wall portion which separates adjacent pairs of first
recesses 42 from each other. The third recess portions 45 are each
opened in regions other than the through-holes 46 in the first
surface 17a, so as to make adjacent pairs of first recess portions
42 communicate with each other. In this modification, the third
recess portions 45 each extend over the most of the region between
two through-holes 46 adjacent in the first direction X.
[0103] According to the seventh modification having the
above-described structure, the area on the first surface 17a which
is brought into in contact with the diaphragm can be further
reduced by providing the third recess portions. Further, the main
reaction region of the electrode is the lower surfaces of the first
recesses R1 and the area of the reaction region can be expanded by
the third recess portions.
[0104] (Eighth Modification)
[0105] FIG. 29 is a partially expanded perspective view showing the
first electrode according to the eighth modification. FIG. 30 is a
plan view of the first electrode as viewed from the first surface
side.
[0106] FIG. 31 is a sectional view of the first electrode and the
anion-exchange membrane, taken along line J-J of FIG. 30.
[0107] As shown in FIGS. 29 and 30, according to the eighth
modification, the basic structure of the first electrode 14 is the
same as that of the seventh modification described above except
that the third recess portions 45 are intermittently formed at two
or more locations in the first direction X in the region between
two through-holes 46 adjacent in the first direction X. That is,
the third recess portions 45 are formed so that the wall portion
which separates the adjacent first recess portions 42 from each
other remain partially. In this modification, for example, four of
the third recess portions 45 are formed in the region between two
through-holes 46 adjacent in the first direction X. Further, the
third recess portions 45 are formed in one row along the second
direction Y.
[0108] In the eighth modification having the above-described
structure, the third recess portions are provided intermittently,
i.e., the length or width of each third recess portion is reduced,
and thus the amount of deformation of the diaphragm which may warp
along the first recesses R1 can be reduced. Therefore, it is
possible to set the positions of the diaphragm and the electrode
more precisely.
[0109] Moreover, according to the eighth modification, as shown in
FIG. 31, the first electrode 14 comprises a catalytic layer 54
formed on the first recess R1 except for the first surface 17a. In
other words, the catalyst is formed on the entire first electrode
14 but the first surface 17a, which is a region brought into
contact with the diaphragm. With this structure, the electrolytic
reaction is prohibited on the first surface in contact with the
diaphragm, thereby making it possible to prolong the life of the
diaphragm.
[0110] Note that the eighth modification is described for the case
where the third recess portions are arranged in line along the
second direction Y, but the arrangement is not limited to this. The
third recess portions may as well be arranged to be shifted from
each other in the first direction, or, for example, in a staggered
manner.
[0111] The present invention is not limited to the embodiments and
modifications described above but the constituent elements of the
invention can be modified in various manners without departing from
the spirit and scope of the invention. Various aspects of the
invention can also be extracted from any appropriate combination of
a plurality of constituent elements disclosed in the embodiments
and modifications. Some constituent elements may be deleted in all
of the constituent elements disclosed in the embodiments. The
constituent elements described in different embodiments may be
combined arbitrarily.
[0112] For example, the first electrode and the second electrode
are not limited to rectangular shapes, but various other forms may
be selected. Further, the material of each structural component is
not limited to that employed in the embodiments or modifications
discussed, but various other materials may be selected as needed.
The electrode structure discussed above may be applied not only to
the first electrode but also to the second electrode (cathode). The
electrolytic cell of the electrode device is not limited to a
three-chamber type, but it may as well be applied to a two-chamber-
or single-chamber type or any electrolytic cells with electrodes in
general. The electrolytes and product are not limited to salt or
hypochlorous acid, but may be developed into various electrolytes
and products.
* * * * *