U.S. patent application number 13/394482 was filed with the patent office on 2012-06-28 for electrolytic device.
This patent application is currently assigned to TOYO TANSO CO., LTD. Invention is credited to Makoto Hongu, Hiroshi Ohkubo, Osamu Yoshimoto.
Application Number | 20120160667 13/394482 |
Document ID | / |
Family ID | 43649121 |
Filed Date | 2012-06-28 |
United States Patent
Application |
20120160667 |
Kind Code |
A1 |
Yoshimoto; Osamu ; et
al. |
June 28, 2012 |
ELECTROLYTIC DEVICE
Abstract
An electrolytic apparatus includes an electrolyzer, a heater,
and a blower. The electrolyzer accommodates an electrolytic bath.
The heater is provided in the electrolyzer while being electrically
insulated from the electrolyzer. Similarly, the blower is provided
in the electrolyzer while being electrically insulated from the
electrolyzer. The heater is turned on so that a temperature of the
electrolyzer rises. The heater is turned off and the blower is
turned on so that a temperature of the electrolyzer falls. The
heater and the blower are switched between ON and OFF so that the
temperature of the electrolyzer is kept constant.
Inventors: |
Yoshimoto; Osamu; (Kagawa,
JP) ; Hongu; Makoto; (Osaka, JP) ; Ohkubo;
Hiroshi; (Kagawa, JP) |
Assignee: |
TOYO TANSO CO., LTD
Osaki-shi
JP
|
Family ID: |
43649121 |
Appl. No.: |
13/394482 |
Filed: |
September 2, 2010 |
PCT Filed: |
September 2, 2010 |
PCT NO: |
PCT/JP2010/005419 |
371 Date: |
March 6, 2012 |
Current U.S.
Class: |
204/274 |
Current CPC
Class: |
C25B 15/02 20130101;
C23F 2213/30 20130101 |
Class at
Publication: |
204/274 |
International
Class: |
C25B 9/00 20060101
C25B009/00; C25B 1/24 20060101 C25B001/24; C25B 15/02 20060101
C25B015/02 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 7, 2009 |
JP |
2009-205491 |
Claims
1. An electrolytic apparatus comprising: an electrolyzer that
accommodates an electrolytic bath; a heating unit that heats said
electrolyzer using its heat source electrically insulated from said
electrolyzer; and a cooling unit that cools said electrolyzer using
its heat dissipation source electrically insulated from said
electrolyzer.
2. The electrolytic apparatus according to claim 1, wherein said
heating unit includes a heater having a heating element that is
coated with an insulating film as said heat source, and said heater
is provided in contact with an outer surface of said
electrolyzer.
3. The electrolytic apparatus according to claim 1, wherein said
heating unit includes an infrared heating device that radiates
infrared rays as said heat source, and said infrared heating device
is spaced apart from said electrolyzer so as to be insulated
therefrom.
4. The electrolytic apparatus according to claim 1, wherein said
cooling unit includes a blower that blows air to said electrolyzer
as said heat dissipation source, and said blower is spaced apart
from said electrolyzer so as to be insulated therefrom.
5. The electrolytic apparatus according to claim 1, wherein said
cooling unit includes a cooling device having a cooling element
that is coated with an insulating film as said heat dissipation
source, and said cooling device is provided in contact with an
outer surface of said electrolyzer.
6. The electrolytic apparatus according to claim 1, wherein a first
chamber is provided in said electrolyzer, and a second chamber is
provided between said first chamber and said electrolyzer, and a
first electrode is arranged in said first chamber, and said
electrolyzer functions as a second electrode.
7. The electrolytic apparatus according to claim 1, further
comprising a controller that controls said heating unit and said
cooling unit so that a temperature of the electrolytic bath in said
electrolyzer is maintained within a predetermined target
temperature range.
8. The electrolytic apparatus according to claim 7, further
comprising a detector that detects a temperature of the
electrolytic bath in said electrolyzer, wherein said controller
stops an operation of said heating unit while operating said
cooling unit when the temperature detected by said detector rises
to a first temperature lower than an upper-limit value of said
target temperature range, and operates said heating unit while
stopping an operation of said cooling unit when the temperature
detected by said detector falls to a second temperature higher than
a lower-limit value of said target temperature range.
9. The electrolytic apparatus according to claim 8, wherein said
controller controls said heating unit and said cooling unit so that
a difference between the upper-limit value and the lower-limit
value of said target temperature range is within two degrees.
10. The electrolytic apparatus according to claim 1, wherein said
electrolyzer is an electrolyzer for fluorine generation.
Description
TECHNICAL FIELD
[0001] The present invention relates to an electrolytic apparatus
including an electrolyzer.
BACKGROUND ART
[0002] Conventionally, in processes for manufacturing
semiconductors, fluorine gases have been used in various
applications such as material cleaning and surface modification. In
this case, the fluorine gases themselves may be used. Various
fluoride-based gases such as NF.sub.3 (nitrogen trifluoride) gas,
NeF (neon fluoride) gas, and ArF (argon fluoride) gas that are
synthesized based on the fluorine gases may be used.
[0003] Electrolytic apparatuses that generate fluorine gases by
electrolyzing HF (hydrogen fluoride) have generally been used to
stably supply the fluorine gases. In such electrolytic apparatuses,
electrolytic baths composed of KF--HF (potassium-hydrogen fluoride)
based mixed molten salts are formed in electrolyzers. The
electrolytic baths in the electrolyzers are electrolyzed so that
fluorine gases are generated. In this case, temperatures of the
electrolytic baths in the electrolyzers are required to be kept in
predetermined ranges to make electrolytic conditions of the
electrolytic apparatuses constant.
[0004] In a molten salt electrolytic apparatus discussed in Patent
Document 1, for example, a hot water jacket is provided on a side
surface on the outer periphery of an electrolyzer. The hot water
jacket includes a hot water pipe and a heat insulating layer. The
hot water pipe is provided to surround the side surface on the
outer periphery of the electrolyzer. In the hot water pipe, a heat
medium heated by a hot water heating device is circulated. In the
electrolyzer, a thermometer is provided. The hot water heating
device heats a heat medium based on a temperature measured by the
thermometer, to keep the electrolytic bath in the electrolyzer at a
predetermined temperature.
[0005] [Patent Document 1] JP 2004-244724 A
SUMMARY OF INVENTION
Technical Problem
[0006] In an electrolyzer in an electrolytic apparatus, at least a
cover portion is required to be grounded to a ground having a
reference potential in preparation for discharges in the
electrolyzer by electric leakage and static electricity. In a hot
water heating device, electric power with large current is handled.
Therefore, the hot water heating device is required to be grounded
to a ground having a reference potential to ensure safety.
[0007] In this case, the cover portion of the electrolyzer is
electrically connected to the electrolyzer through an electrolytic
bath. When a heat medium has conductivity, a closed circuit
including the cover portion of the electrolyzer, the electrolytic
bath, the electrolyzer, the heat medium having conductivity, the
hot water heating device, and the ground is formed. When
electrolization is started using the electrolyzer forming the
closed circuit, a current due to a potential difference in the
electrolyzer flows in the closed circuit, and electrochemistry
corrosion occurs in a metal portion included in the closed
circuit.
[0008] In order to prevent such electrochemistry corrosion, Patent
Document 1 discusses a countermeasure using a piping at least a
part of which is insulated and a heat medium having high insulation
properties. However, a heat medium being an insulating solvent
(e.g., a fluorine-based solvent) and having such a large heat
capacity that a temperature of the electrolyzer can be adjusted
does not exist. Therefore, an example of the heat medium having a
relatively high electrical resistance and having a large heat
capacity is pure water. However, the pure water slightly has
electric conductivity. Therefore, the above-mentioned
electrochemistry corrosion in the metal portion is not completely
prevented.
[0009] An object of the present invention is to provide an
electrolytic apparatus capable of ensuring a heat capacity in which
a temperature of an electrolyzer can be sufficiently adjusted while
reliably preventing electrochemistry corrosion due to a potential
difference.
Solution to Problem
[0010] (1) According to an aspect of the present invention, an
electrolytic apparatus includes an electrolyzer that accommodates
an electrolytic bath, a heating unit that heats the electrolyzer
using its heat source electrically insulated from the electrolyzer,
and a cooling unit that cools the electrolyzer using its heat
dissipation source electrically insulated from the
electrolyzer.
[0011] In the electrolytic apparatus according to the aspect of the
present invention, the heat source of the heating unit is
electrically insulated from the electrolyzer, and the heat
dissipation source of the cooling unit is electrically insulated
from the electrolyzer. In this state, the electrolyzer is heated by
the heat source of the heating unit, and is cooled by the heat
dissipation source of the cooling unit.
[0012] In this case, the electrolyzer is directly heated and cooled
by the heat source and the heat dissipation source, unlike that in
heat exchange using a heat medium. Thus, a temperature of the
electrolyzer can be sufficiently adjusted.
[0013] A potential is not fed to the electrolyzer via the heat
source and the heat dissipation source. Therefore, electrochemistry
corrosion in the electrolytic apparatus due to the potential
difference in the electrolyzer can be reliably prevented. [0014]
(2) The heating unit may include a heater having a heating element
that is coated with an insulating film as the heat source, and the
heater may be provided in contact with an outer surface of the
electrolyzer.
[0015] In this case, the heating element of the heater is provided
in contact with the outer surface of the electrolyzer with the
insulating film interposed therebetween. Therefore, the
electrolyzer is directly heated by heat conduction from the heating
element of the heater to the electrolyzer. Thus, the electrolyzer
can be heated with high responsiveness. [0016] (3) The heating unit
may include an infrared heating device that radiates infrared rays
as the heat source, and the infrared heating device may be spaced
apart from the electrolyzer so as to be insulated therefrom.
[0017] In this case, the infrared rays are radiated from the
infrared heating device spaced apart from the electrolyzer to the
electrolyzer. Thus, the electrolyzer is directly heated by heat
radiation. The infrared heating device is reliably insulated from
the electrolyzer. [0018] (4) The cooling unit may include a blower
that blows air to the electrolyzer as the heat dissipation source,
and the blower may be spaced apart from the electrolyzer so as to
be insulated therefrom.
[0019] In this case, the blower spaced apart from the electrolyzer
blows air to the electrolyzer. Thus, the electrolyzer is directly
cooled by air circulation. The blower is reliably insulated from
the electrolyzer. [0020] (5) The cooling unit may include a cooling
device having a cooling element that is coated with an insulating
film as the heat dissipation source, and the cooling device may be
provided in contact with an outer surface of the electrolyzer.
[0021] In this case, the cooling element is provided in contact
with the outer surface of the electrolyzer with the insulating film
interposed therebetween. Thus, the electrolyzer is directly cooled
by absorption of heat from the electrolyzer to the cooling device.
Thus, the electrolyzer can be cooled with high responsiveness.
[0022] (6) A first chamber may be provided in the electrolyzer, and
a second chamber may be provided between the first chamber and the
electrolyzer, and a first electrode may be arranged in the first
chamber, and the electrolyzer may function as a second
electrode.
[0023] In this case, the electrolyzer electrically insulated from
an installation surface, the heat source, and the heat dissipation
source functions as a second electrode. Therefore, a stable and
accurate voltage can be applied between the first electrode and the
second electrode. [0024] (7) The electrolytic apparatus may further
include a controller that controls the heating unit and the cooling
unit so that a temperature of the electrolytic bath in the
electrolyzer is maintained within a predetermined target
temperature range.
[0025] In this case, the controller controls heating of the
electrolyzer by the heating unit and cooling of the electrolyzer by
the cooling unit. Thus, a temperature in the electrolyzer can be
stably and reliably kept within the target temperature range.
[0026] (8) The electrolytic apparatus may further include a
detector that detects a temperature of the electrolytic bath in the
electrolyzer, and the controller may stop an operation of the
heating unit while operating the cooling unit when the temperature
detected by the detector rises to a first temperature lower than an
upper-limit value of the target temperature range, and may operate
the heating unit while stopping an operation of the cooling unit
when the temperature detected by the detector falls to a second
temperature higher than a lower-limit value of the target
temperature range.
[0027] In this case, when the temperature of the electrolyzer rises
to the first temperature lower than the upper-limit value of the
target temperature range, the operation of the heating unit is
stopped while the cooling unit operates. Thus, the temperature of
the electrolyzer can be prevented from exceeding the upper-limit
value of the target temperature range due to overshoot.
[0028] When the temperature of the electrolyzer falls to the second
temperature higher than the lower-limit value of the target
temperature range, the heating unit operates while the operation of
the cooling unit is stopped. Thus, the temperature of the
electrolyzer can be prevented from being the lower-limit value or
less of the target temperature range due to undershoot.
[0029] Further, the heating unit is stopped while the cooling unit
operates, and the heating unit operates while the cooling unit is
stopped. Thus, an overshoot amount and an undershoot amount at the
temperature of the electrolyzer can be reduced. As a result, the
target temperature range can be reduced, and the temperature of the
electrolyzer can be kept substantially constant. [0030] (9) The
controller may control the heating unit and the cooling unit so
that a difference between the upper-limit value and the lower-limit
value of the target temperature range is within two degrees.
[0031] In this case, the temperature of the electrolyzer is kept
substantially constant. Therefore, an electrolyzation condition is
kept substantially constant. Thus, more stable electrolyzation can
be performed. [0032] (10) The electrolyzer may be an electrolyzer
for fluorine generation. Vapor pressure of a fluorine compound used
as the electrolytic bath greatly changes with temperature. In such
a case, the temperature of the electrolytic bath is also controlled
stably and with high accuracy. Therefore, a vapor of a fluorine
compound can be prevented from being released from the electrolytic
bath in the electrolyzer.
ADVANTAGEOUS EFFECTS OF INVENTION
[0033] According to the present invention, there can be provided an
electrolytic apparatus that controls a temperature of an
electrolytic bath in an electrolyzer stably and with high accuracy
in a low-cost and simple configuration.
BRIEF DESCRIPTION OF DRAWINGS
[0034] FIG. 1 is a schematic sectional view of an electrolytic
apparatus according to an embodiment of the present invention.
[0035] FIG. 2 is a schematic view on the outer side of mainly an
electrolyzer in the electrolytic apparatus illustrated in FIG.
1.
[0036] FIG. 3 is a flowchart illustrating a control operation of a
heater and a blower by a controller.
[0037] FIG. 4 illustrates results of temperatures of electrolytic
bathes in an inventive example and a comparative example.
[0038] FIG. 5 is a schematic view on the outer side of mainly an
electrolyzer in an electrolytic apparatus according to another
embodiment of the present invention.
[0039] FIG. 6 is a schematic view on the outer side of mainly an
electrolyzer in an electrolytic apparatus according to still
another embodiment of the present invention.
DESCRIPTION OF EMBODIMENTS
[0040] The embodiments of the present invention will be described
in detail referring to the drawings. The embodiments below describe
an electrolytic apparatus.
(1) Configuration of Electrolytic Apparatus
[0041] FIG. 1 is a schematic sectional view of an electrolytic
apparatus according to an embodiment of the present invention. FIG.
2 is a schematic view on the outer side of mainly an electrolyzer
in the electrolytic apparatus illustrated in FIG. 1.
[0042] The electrolytic apparatus 10 illustrated in FIG. 1 is a gas
generation apparatus that generates a fluorine gas. The
electrolytic apparatus 10 includes an electrolyzer 11. The
electrolyzer 11 includes an electrolyzer main body 11a, an upper
cover 11b, and an insulating member 11c.
[0043] The electrolyzer main body 11a and the upper cover 11b are
formed of a metal such as Ni (Nickel), Monel, pure iron, or
stainless steel or its alloy, for example.
[0044] The electrolyzer main body 11a has a bottom portion and four
side portions, and has an opening in its upper part. The insulating
member 11c is provided along upper end surfaces of the side
portions. The insulating member 11c is formed of an insulating
material such as resin. The upper cover 11b is arranged on the
insulating member 11c to close the opening of the electrolyzer main
body 11a. Thus, the insulating member 11c electrically insulates
the electrolyzer main body 11a and the upper cover 11b from each
other.
[0045] In the electrolyzer 11, electric power with large current is
handled. Discharges in the electrolyzer 11 by static electricity
are required to be prevented. Therefore, a ground wire S1 grounds
the upper cover 11b in the electrolyzer 11 to a ground E. Thus, an
electric shock or the like by electric leakage from the
electrolyzer 11 is prevented.
[0046] A plurality of supporting members 31 composed of an
insulating material support the electrolyzer 11 in a housing 32
composed of a conductive material. The supporting member 31 is
formed of Bakelite, for example. Wheels 33 composed of an
insulating material are attached to a bottom surface of the housing
32. In this manner, the electrolyzer 11 is electrically insulated
from the housing 32, and the housing 32 is electrically insulated
from an installation surface.
[0047] An electrolytic bath 12 composed of a KF--HF
(potassium-hydrogen fluoride) based mixed molten salt is formed in
the electrolyzer 11. A cylindrical partition wall 13 is provided
integrally with the upper cover 11b so that its part is immersed in
the electrolytic bath 12. The partition wall 13 is composed of Ni
or Monel, for example. In the electrolyzer 11, an anode chamber 14a
is formed inside the partition wall 13, and a cathode chamber 14b
is formed outside the partition wall 13.
[0048] An anode 15a is arranged to be immersed in the electrolytic
bath 12 within the anode chamber 14a. A low-polarizable carbon
electrode, for example, is preferably used as a material for the
anode 15a. A cathode 15b is formed on an inner surface of the
electrolyzer main body 11a. A hydrogen gas is mainly generated in
the cathode chamber 14b. Ni, for example, is preferably used as a
material for the cathode 15b.
[0049] An HF supply line 18a for supplying HF is connected to the
upper cover 11b. The HF supply line 18a is covered with a
temperature adjustment heater 18b. Thus, HF is prevented from being
liquefied in the HF supply line 18a. A liquid level detection
device (not illustrated) detects the height of a liquid level of
the electrolytic bath 12. When the height of the liquid level
detected by the liquid level detection device becomes lower than a
predetermined value, HF is supplied to the electrolyzer 11 through
the HF supply line 18a.
[0050] The electrolytic apparatus 10 includes a controller 23. The
controller 23 applies a voltage between the anode 15a and the
cathode 15b. Thus, the electrolytic bath 12 in the electrolyzer 11
is electrolyzed. Thus, a fluorinate gas is mainly generated in the
anode chamber 14a.
[0051] The upper cover 11b is provided with gas exhaust ports 16a
and 16b. An exhaust pipe 17a is connected to the gas exhaust port
16a, and an exhaust pipe 17b is connected to the gas exhaust port
16b. The gas exhaust port 16a communicates with the anode chamber
14a, and the gas exhaust port 16b communicates with the cathode
chamber 14b. A gas generated by the anode chamber 14a is discharged
from the gas exhaust port 16a through the exhaust pipe 17a, and a
gas generated by the cathode chamber 14b is discharged from the gas
exhaust port 16b through the exhaust pipe 17b.
[0052] The electrolyzer 11 includes a heater 21a and a blower 21b.
In the present embodiment, a sheathed heater is used as the heater
21a. The sheathed heater has a configuration in which an
electrically-heated wire is coated with an insulating film. The
sheathed heater can obtain a desired heat capacity using the
electrically-heated wire. The electrolyzer 11 can be quickly heated
by providing the heater 21a in contact with the electrolyzer 11.
The heater 21a is electrically insulated from the electrolyzer 11,
although provided in contact with the electrolyzer 11.
[0053] As illustrated in FIG. 2, the heater 21a is attached to
outer surfaces of the side portions of the electrolyzer main body
11a so as to have a meander shape. Thus, a contact area between the
heater 21a and the electrolyzer main body 11a increases. The heater
21a heats the electrolyzer 11 with heat conduction.
[0054] The blower 21b is spaced apart from the electrolyzer 11 so
as to be insulated therefrom, and blows air to the electrolyzer 11.
Thus, the blower 21b cools the electrolyzer 11 with air circulation
in the state of being electrically insulated from the electrolyzer
11.
[0055] The heater 21a and the blower 21b operate by electric power
supplied from a power supply device 21. The power supply device 21
is grounded to the ground E via a ground wire S2 to ensure
safety.
[0056] In the present embodiment, the insulating film provided in
the sheathed heater serving as the heater 21a electrically
insulates the heater 21a and the electrolyzer 11 from each other.
Air serving as an insulator electrically insulates the blower 21b
and the electrolyzer 11 from each other. In this case, if the upper
cover 11b and a power supply device 21 are grounded to the ground
E, to form a closed circuit, a current due to a potential
difference in the electrolyzer 11 does not flow through a metal
portion of the electrolytic apparatus. Thus, electrochemistry
corrosion in a metal portion of the electrolytic apparatus is
prevented.
[0057] The electrolytic apparatus 10 is provided with a temperature
sensor 22a that detects a temperature of the heater 21a and a
temperature sensor 22b that detects a temperature of the
electrolytic bath 12 in the electrolyzer main body 11a. In the
present embodiment, the temperature sensors 22a and 22b are
composed of a thermocouple.
[0058] The controller 23 controls the heater 21a and the blower 21b
based on a temperature of the electrolyzer 11 detected by the
temperature sensor 22a and a temperature of the electrolytic bath
12 detected by the temperature sensor 22b.
(2) Temperature Control Operation
[0059] An operation for controlling the temperature of the
electrolytic bath 12 in the electrolyzer 11 by the controller 23
will be described below.
[0060] The electrolytic bath 12 in the electrolyzer 11 assumes a
solid state at room temperature and under atmospheric pressure.
Therefore, the electrolytic bath 12 is required to be heated to not
less than 80.degree. C. nor more than 90.degree. C. and dissolved
in a liquid state to electrolyze the electrolytic bath 12.
[0061] When a current flows through the anode 15a, the cathode 15b,
and the electrolytic bath 12 during the electrolyzation, Joule heat
due to electric resistances of the anode 15a, the cathode 15b, and
the electrolytic bath 12 is generated. When the electrolytic bath
12 is dissolved, heat of dissolution is generated. Thus, the
temperature of the electrolytic bath 12 excessively rises. As a
result, vapor pressure of HF in the electrolytic bath 12 increases
so that HF is released from the electrolytic bath 12. In this case,
the purity of a fluorine gas taken out of the exhaust pipe 17a may
decrease, and the electrolyzation efficiency of HF may decrease.
Therefore, the temperature of the electrolytic bath 12 is required
to be maintained in an appropriate temperature range.
[0062] First, the controller 23 turns on the heater 21a. Thus, the
temperature of the electrolyzer 11 rises, and the temperature of
the electrolytic bath 12 in the electrolyzer 11 also rises. The
controller 23 controls ON and OFF of the heater 21a based on the
temperature detected by the temperature sensor 22a until the
electrolytic bath 12 is dissolved. The temperature of the
electrolyzer 11 (hereinafter referred to as a lower-limit
electrolyzer temperature) obtained when the electrolytic bath 12 is
dissolved is previously measured.
[0063] The controller 23 turns off the heater 21a when the
temperature detected by the temperature sensor 22a becomes an
upper-limit value (hereinafter referred to as an upper-limit
electrolyzer temperature) previously set to prevent the temperature
of the electrolyzer 11 from excessively rising.
[0064] When the electrolytic bath 12 is dissolved, the temperature
sensor 22b can detect the temperature of the electrolytic bath 12.
When electrolyzation is started, Joule heat or the like is
generated so that an amount of heat larger than an amount of heat
lost by natural heat dissipation is put into the electrolytic bath
12. Thus, the temperature of the electrolytic bath 12 rises even in
a state where the heater 21a is stopped.
[0065] The controller 23 controls ON and OFF of the heater 21a and
the blower 21b based on the temperature detected by the temperature
sensor 22b when the temperature detected by the temperature sensor
22a becomes the lower-limit electrolyzer temperature or more.
[0066] FIG. 3 is a flowchart illustrating a control operation of
the heater 21a and the blower 21b by the controller 23.
[0067] Hereinafter, an upper-limit value of a temperature range of
an electrolytic bath most suitable for electrolyzation is referred
to as a target upper-limit temperature, and a lower-limit value of
the temperature range of the electrolytic bath most suitable for
electrolyzation is referred to as a target lower-limit
temperature.
[0068] A temperature at which the heater 21a is turned off and the
blower 21b is turned on so that the temperature of the electrolytic
bath does not exceed the target upper-limit temperature is referred
to as a cooling start temperature, and a temperature at which the
heater 21a is turned on and the blower 21b is turned off so that
the temperature of the electrolytic bath does not decrease beyond
the target lower-limit temperature is referred to as a heating
start temperature. The cooling start temperature is set to a value
lower by a predetermined temperature (e.g., one degree) than the
target upper-limit temperature, and the heating start temperature
is set to a value higher by a predetermined temperature (e.g., one
degree) than the target lower-limit temperature.
[0069] In an initial state, the heater 21a is turned on, and the
blower 21b is turned off.
[0070] The controller 23 determines whether the temperature of the
electrolytic bath 12 detected by the temperature sensor 22b rises
to the cooling start temperature (step S1). If the temperature of
the electrolytic bath 12 does not rise to the cooling start
temperature, the controller 23 waits until the temperature of the
electrolytic bath 12 reaches the cooling start temperature. If the
temperature of the electrolytic bath 12 rises to the cooling start
temperature, the controller 23 turns off the heater 21a (step S2),
and turns on the blower 21b (step S3).
[0071] The controller 23 then determines whether the temperature of
the electrolytic bath 12 detected by the temperature sensor 22b
falls to the heating start temperature (step S4). If the
temperature of the electrolytic bath 12 does not fall to the
heating start temperature, the controller 23 waits until the
temperature of the electrolytic bath 12 reaches the heating start
temperature. If the temperature of the electrolytic bath 12 falls
to the heating start temperature, the controller 23 turns on the
heater 21a (step S5), and turns off the blower 21b (step S6), and
the processing returns to step S1.
[0072] In this manner, the temperature of the electrolytic bath 12
is kept between a target upper-limit temperature higher by a
predetermined temperature than the cooling start temperature and a
target lower-limit temperature lower by a predetermined temperature
than the heating start temperature.
(3) Effects of Embodiment
[0073] In the electrolytic apparatus 10 according to the present
embodiment, the electrolyzer 11 is supported by the supporting
member 31 to be electrically insulated from the housing 32. The
heater 21a and the blower 21b are electrically insulated from the
electrolyzer 11. In this state, the electrolyzer 11 is heated by
heat conduction from the heater 21a, and is cooled by air
circulation from the blower 21b.
[0074] In this case, a potential is not applied to the electrolyzer
11 via the heater 21a and the blower 21b. Therefore, the corrosion
in the electrolyzer 11 can be prevented by applying a stable
anticorrosion voltage to the electrolyzer 11. Thus, the maintenance
cost of the electrolyzer 11 can be reduced.
[0075] The electrolyzer 11 is heated by heat conduction, and is
cooled by air circulation. In this case, a heat medium having
insulation properties for heating and cooling the electrolyzer 11
is not required. Therefore, the electrolyzer 11 can be heated and
cooled in a low-cost and simple configuration.
[0076] Further, the electrolyzer 11 is directly heated and cooled
by heat conduction from the heater 21a and air circulation form the
blower 21b, unlike that in heat exchange using a heat medium. Thus,
the temperature of the electrolytic bath 12 in the electrolyzer 11
can be controlled stably and with high accuracy.
(4) Examples
[0077] In an inventive example and a comparative example, described
below, the electrolytic apparatus 10 illustrated in FIGS. 1 and 2
was used, to control the temperature of the electrolytic bath 12.
An electrolytic apparatus used in the comparative example had the
same configuration as that of the electrolytic apparatus 10
illustrated in FIGS. 1 and 2 except that the blower 21b was not
attached thereto.
[0078] In the inventive example and the comparative example, the
heating start temperature and the cooling start temperature of the
electrolytic bath 12 were respectively set to 85.degree. C. and
86.degree. C.
[0079] In the inventive example, when the temperature of the
electrolytic bath 12 detected by the temperature sensor 22b rose to
86.degree. C., the heater 21a was turned off while the blower 21b
was turned on so that the electrolytic bath 12 was forcedly cooled
by air blowing. When the temperature of the electrolytic bath 12
detected by the temperature sensor 22b fell to 85.degree. C., the
heater 21a was turned on while the blower 21b was turned off so
that the electrolytic bath 12 was heated.
[0080] On the other hand, in the comparative example, when the
temperature of the electrolytic bath 12 detected by the temperature
sensor 22b rose to 86.degree. C., the heater 21a was turned off
while the electrolytic bath 12 was naturally cooled. When the
temperature of the electrolytic bath 12 detected by the temperature
sensor 22b fell to 85.degree. C., the heater 21a was turned on, and
the electrolytic bath 12 was heated.
[0081] FIGS. 4 (a) and 4 (b) are diagrams respectively illustrating
results of the temperatures of the electrolytic bathes 12 in the
inventive example and the comparative example. In FIG. 4, the
horizontal axis indicates time, and the vertical axis indicates the
temperature of the electrolytic bath 12.
[0082] As illustrated in FIG. 4 (a), in the inventive example, a
variation in the temperature of the electrolytic bath 12 was
controlled within a range of two degrees for a period of 889
minutes. On the other hand, in the comparative example, a variation
in the temperature of the electrolytic bath 12 was four degrees or
more for a period of 865 minutes.
[0083] As apparent from the results of the inventive example and
the comparative example, the heater 21a as well as the blower 21b
was used so that the variation in the temperature of the
electrolytic bath 12 could be kept approximately constant.
(5) Another Embodiment
[0084] FIG. 5 is a schematic view on the outer side of mainly an
electrolyzer in an electrolytic apparatus according to another
embodiment of the present invention.
[0085] An electrolytic apparatus 10 illustrated in FIG. 5 differs
from the electrolytic apparatus 10 illustrated in FIGS. 1 and 2 in
that a plurality of infrared heating devices 21c are arranged
around an electrolyzer 11 in place of the heater 21a.
[0086] The plurality of infrared heating devices 21c are spaced
apart from the electrolyzer 11, to radiate infrared rays to the
electrolyzer 11. Thus, the plurality of infrared heating devices
21c heat the electrolyzer 11 by heat radiation in the state of
being electrically insulated from the electrolyzer 11.
[0087] FIG. 6 is a schematic view on the outer side of mainly an
electrolyzer in an electrolytic apparatus according to still
another embodiment of the present invention.
[0088] An electrolytic apparatus 10 illustrated in FIG. 6 differs
from the electrolytic apparatus 10 illustrated in FIGS. 1 and 2 in
that a plurality of cooling devices 21d are attached thereto in a
distributed manner in contact with outer surfaces of side portions
of an electrolyzer main body 11a in place of the blower 21b. The
cooling device 21d has a configuration in which a Peltier element
is insulated by being coated with a ceramic material, an insulating
film and the like. Thus, a plurality of cooling devices 21d cool
the electrolyzer 11 by performing a heat absorption operation in
the state of being electrically insulated from the electrolyzer
11.
[0089] The plurality of infrared heating devices 21c may be
provided in place of the heater 21a illustrated in FIGS. 1 and 2,
and the plurality of cooling devices 21d may be provided in place
of the blower 21b.
(6) Correspondences between Elements in the Claims and Parts in
Embodiments
[0090] In the following paragraphs, non-limiting examples of
correspondences between various elements recited in the claims
below and those described above with respect to various preferred
embodiments of the present invention are explained.
[0091] The heater 21a and the infrared heating device 21c are
examples of a heat source and a heating unit, the blower 21b and
the cooling device 21d are examples of a heat dissipation source
and a cooling unit, the electrically-heated wire of the sheathed
heater is an example of a heating element, the heater 21a is an
example of a heater, the Peltier element is an example of a cooling
element, the anode chamber 14a is an example of a first chamber,
the cathode chamber 14b is an example of a second chamber, the
anode 15a is an example of a first electrode, the cathode 15b is an
example of a second electrode, the controller 23 is an example of a
controller, and the temperature sensor 22b is an example of a
detector.
[0092] As each of various elements recited in the claims, various
other elements having configurations or functions described in the
claims can be also used.
INDUSTRIAL APPLICABILITY
[0093] The present invention is effectively applicable to an
electrolytic apparatus such as a gas generation apparatus.
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