Electrolytic gas converter and electric equipment using the same

Abstract

In an electrolytic gas converter for converting atmospheric moisture into ozone gas, oxygen gas or hydrogen gas, the electrolytic gas converter is provided with a unit for making control so that an electric current is supplied to the electrochemical device conjunctive body during a predetermined period of time after the start of the operation of gas conversion, the electric current being larger than that after the predetermined period of time passes. In addition, the control unit controls the current to flow periodically. Further, the electrolytic gas converter is provided with a unit for making control so that a predetermined constant current is supplied to the electrochemical device conjunctive body after the predetermined period of time passes since the operation of gas conversion is started.

Description

BACKGROUND OF THE INVENTION

[0001] The present invention relates to an electrolytic gas converter based on electrochemical reaction using a solid polymer electrolyte membrane, and more particularly relates to an electrolytic gas converter, such as an ozone generator, an oxygen generator, a hydrogen generator or a dehumidifier, in which a DC voltage is applied between an anode and a cathode opposed to each other through a solid polymer electrolyte membrane so that atmospheric moisture is converted into ozone gas, oxygen gas or hydrogen gas in accordance with electrochemical reaction.

[0002] FIG. 21 is a diagram showing the configuration of an ozone generator which is one of related-art electrolytic gas converters, disclosed in the Unexamined Japanese Patent Application Publication No. Hei 11-131276. In FIG. 21, an anode 1 has an anode catalyst layer on an anode substrate made of a conductive porous base material. A cathode 2 has a cathode catalyst layer on a cathode substrate made of a conductive porous base material. The anode 1 and the cathode 2 are disposed on the front and back surfaces of a solid polymer electrolyte membrane 3, and bonded thereto by thermo compression. Thus, an electrochemical device conjunctive body 8 is formed. The reference numeral 4 represents an anode terminal provided on the anode 1; 5, a cathode terminal provided on the cathode 2; 6, a DC power supply; and 7, a connection wire for connecting the DC power supply 6, the anode 1 and the cathode 2.

[0003] Incidentally, as the anode 1, for example, there is used an anode in which &bgr;-type or &agr;-type lead dioxide is thinly electrodeposited on an expanded metal substrate made of titanium and plated with platinum as undercoat. As the cathode 2, for example, there is used a cathode in which a solid polymer electrolyte obtained by liquefying carbon powder carrying platinum fine particles is fixedly attached as binder onto a porous carbon fiber substrate.

[0004] Next, description will be made on the operation. For example, when a voltage of 3 V is applied to the electrochemical device conjunctive body 8 by the DC power supply 6, atmospheric moisture is electrolyzed in the conjunction surface between the anode 1 and the solid polymer electrolyte membrane 3 in accordance with electrochemical reaction formulae (1) and (2). Thus, hydrogen ions are generated as soon as ozone gas, oxygen gas and electrons are generated.

2H2O→O2+4H++4e  (1)

3H2O→O3+6H++6e  (2)

[0005] The ozone gas and the oxygen gas generated thus flow out to the outside air through the porous anode 1. On the other hand, the generated hydrogen ions move to the cathode 2 through the solid polymer electrolyte membrane 3. In the conjunction surface between the cathode 2 and the solid polymer electrolyte membrane 3, the hydrogen ions react with oxygen gas in the air and the electrons introduced into the cathode 2 through the connection wire 7 so as to generate water. The water flows out to the outside air through the porous cathode 2.

[0006] Incidentally, when the electrochemical device conjunctive body 8 is used for oxygen gas generation or dehumidification, that is, when the electrolytic gas converter is an oxygen gas generator or a dehumidifier, for example, a porous expanded metal substrate made of titanium and plated with platinum is used as the anode 1 of the electrochemical device conjunctive body 8. In this case, oxygen is generated from the anode while water is released from the back of the cathode.

[0007] When the electrochemical device conjunctive body 8 is used for hydrogen gas generation, that is, when the electrolytic gas converter is a hydrogen gas generator, for example, a porous expanded metal substrate made of titanium and plated with platinum is used as each of the anode 1 and the cathode 2. In this case, hydrogen gas is generated in the cathode.

[0008] The related-art electrolytic gas converter is arranged as described above. When the electrolytic gas converter is operated intermittently in high humidity environment, the solid polymer electrolyte membrane 3 retains excessive moisture after the operation of gas conversion is suspended. When the operation of gas conversion is restarted, the resistance of the electrochemical device conjunctive body 8 is lowered significantly so that a voltage necessary for generation of gas by electrochemical reaction cannot be ensured. Thus, there is a problem that the gas generation of the electrochemical device conjunctive body 8 becomes unstable.

[0009] Particularly, in the case of ozone gas generation, when the voltage applied to the electrochemical device conjunctive body 8 (hereinafter referred to as “load voltage”) is lower than 3 V, ozone generation becomes unstable. Thus, there is a problem that the quantity of generated ozone gas is lowered significantly.

SUMMARY OF THE INVENTION

[0010] The invention is developed to solve these foregoing problems. It is an object of the invention to obtain an electrolytic gas converter in which in intermittent operation in high humidity environment, the quantity of converted gas can be prevented from being lowered significantly at the start of the operation of gas conversion, and the quantity of converted gas can be kept stable during the operation of gas conversion.

[0011] In addition, it is another object of the invention to provide electric equipment which has this electrolytic gas converter and in which the quantity of converted gas can be kept stable during the operation of gas conversion in intermittent operation in high humidity environment.

[0012] According to the invention, there is provided a first electrolytic gas converter including: an electrochemical device conjunctive body having an anode and a cathode each having a catalyst layer provided on a substrate made of a conductive porous base material, and a solid polymer electrolyte membrane disposed between the anode and the cathode, a DC voltage being applied to the electrochemical device conjunctive body so as to convert atmospheric moisture into ozone gas, oxygen gas or hydrogen gas; and a unit for making control so that an electric current flows into the electrochemical device conjunctive body during a predetermined period of time after start of operation of gas conversion, the electric current being larger than that after the predetermined period of time passes.

[0013] According to the invention, there is provided a second electrolytic gas converter in which in the first electrolytic gas converter, a unit is provided for making control so that an electric current is made to flow into the electrochemical device conjunctive body periodically during a predetermined period of time after start of operation of gas conversion, the electric current being larger than that after the predetermined period of time passes.

[0014] According to the invention, there is provided a third electrolytic gas converter in which in the first electrolytic gas converter, a unit is provided for making control so that a predetermined constant electric current flows into the electrochemical device conjunctive body after the predetermined period of time passes since the start of operation of gas conversion.

[0015] According to the invention, there is provided a fourth electrolytic gas converter including: an electrochemical device conjunctive body having an anode and a cathode each having a catalyst layer provided on a substrate made of a conductive porous base material, and a solid polymer electrolyte membrane disposed between the anode and the cathode, a DC voltage being applied to the electrochemical device conjunctive body so as to convert atmospheric moisture into ozone gas, oxygen gas or hydrogen gas; and a unit for making control so that a voltage low enough or an electric current small enough not to convert the moisture into the gas is applied or conducted to the electrochemical device conjunctive body during suspension of operation of gas conversion.

[0016] According to the invention, there is provided a fifth electrolytic gas converter in which in the fourth electrolytic gas converter, a unit is provided for making control so that a predetermined constant electric current flows into the electrochemical device conjunctive body during the operation of gas conversion.

[0017] According to the invention, there is provided a sixth electrolytic gas converter including: an electrochemical device conjunctive body having an anode and a cathode each having a catalyst layer provided on a substrate made of a conductive porous base material, and a solid polymer electrolyte membrane disposed between the anode and the cathode, a DC voltage being applied to the electrochemical device conjunctive body so as to convert atmospheric moisture into ozone gas, oxygen gas or hydrogen gas; and a unit for making control so that an electric current is made to flow into the electrochemical device conjunctive body in a case where a voltage applied to the electrochemical device conjunctive body is lower than a predetermined voltage, the electric current being larger than in another case where the voltage is higher than the predetermined voltage.

[0018] According to the invention, there is provided a seventh electrolytic gas converter in which in the sixth electrolytic gas converter, a unit is provided for making control so that a predetermined constant electric current is made to flow into the electrochemical device conjunctive body when a voltage applied to the electrochemical device conjunctive body is not lower than a predetermined voltage.

[0019] According to the invention, there is provided an eighth electrolytic gas converter in which in the first or sixth electrolytic gas converter, a unit is provided for making control so that a circuit connected to the electrochemical device conjunctive body is released during suspension of operation of gas conversion.

[0020] According to the invention, there is provided a ninth electrolytic gas converter in which in the any one of the first through eighth electrolytic gas converters, the electrochemical device conjunctive body is used as an ozone generating device, an oxygen generating device, a hydrogen generating device, or a dehumidifying device.

[0021] According to the invention, there is provided first electric equipment having any one of the first through eighth electrolytic gas converters.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIG. 1

[0023] FIG. 1 is a diagram for explaining a configuration of an electrolytic gas converter according to Embodiment 1 of the invention.

[0024] FIG. 2

[0025] FIG. 2 is a diagram concerned with Embodiment 1 of the invention and for explaining the operation of the electrolytic gas converter according to Embodiment 1.

[0026] FIG. 3

[0027] FIG. 3 is a diagram for explaining a configuration of an electrolytic gas converter according to Embodiment 2 of the invention.

[0028] FIG. 4

[0029] FIG. 4 is a diagram for explaining a configuration of an electrolytic gas converter according to Embodiment 3 of the invention.

[0030] FIG. 5

[0031] FIG. 5 is a diagram concerned with Embodiment 3 of the invention and for explaining the operation of the electrolytic gas converter according to Embodiment 3.

[0032] FIG. 6

[0033] FIG. 6 is a diagram for explaining a configuration of an electrolytic gas converter according to Embodiment 4 of the invention.

[0034] FIG. 7

[0035] FIG. 7 is a diagram for explaining a configuration of an electrolytic gas converter according to Embodiment 5 of the invention.

[0036] FIG. 8

[0037] FIG. 8 is a diagram for explaining another configuration of an electrolytic gas converter according to Embodiment 5 of the invention.

[0038] FIG. 9

[0039] FIG. 9 is a diagram for explaining a configuration of an electrolytic gas converter according to Embodiment 6 of the invention.

[0040] FIG. 10

[0041] FIG. 10 is a diagram for explaining a configuration of an electrolytic gas converter according to Embodiment 7 of the invention.

[0042] FIG. 11

[0043] FIG. 11 is a diagram for explaining another configuration of an electrolytic gas converter according to Embodiment 7 of the invention.

[0044] FIG. 12

[0045] FIG. 12 is a diagram for explaining a configuration of an electrolytic gas converter according to Embodiment 8 of the invention.

[0046] FIG. 13

[0047] FIG. 13 is a diagram for explaining a configuration of an electrolytic gas converter according to Embodiment 9 of the invention.

[0048] FIG. 14

[0049] FIG. 14 is a diagram for explaining a configuration of an electrolytic gas converter according to Embodiment 10 of the invention.

[0050] FIG. 15

[0051] FIG. 15 is a diagram concerned with Embodiment 10 of the invention and for explaining the relationship between a current and a voltage flowing into an electrochemical device conjunctive body.

[0052] FIG. 16

[0053] FIG. 16 is a diagram for explaining a configuration of an electrolytic gas converter according to Embodiment 11 of the invention.

[0054] FIG. 17

[0055] FIG. 17 is a diagram concerned with Embodiment 11 of the invention and for explaining the relationship between a current and a voltage flowing into an electrochemical device conjunctive body.

[0056] FIG. 18

[0057] FIG. 18 is a diagram for explaining a configuration of an electrolytic gas converter according to Embodiment 12 of the invention.

[0058] FIG. 19

[0059] FIG. 19 is a diagram concerned with Embodiment 12 of the invention and for explaining the relationship between a current and a voltage flowing into an electrochemical device conjunctive body.

[0060] FIG. 20

[0061] FIG. 20 is a diagram for explaining a configuration of an electrolytic gas converter according to Embodiment 13 of the invention.

[0062] FIG. 21

[0063] FIG. 21 is a diagram for explaining a configuration of a related-art electrolytic gas converter.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0064] (Embodiment 1)

[0065] An ozone generator will be chiefly described below as an electrolytic gas converter according to Embodiment 1 of the invention by way of example. FIG. 1 is a diagram for explaining the configuration of the electrolytic gas converter according to Embodiment 1 of the invention.

[0066] In FIG. 1, the reference numeral 1 represents an anode having a catalyst layer provided on a substrate made of a conductive porous base material; 2, a cathode having a catalyst layer provided on a substrate made of a conductive porous base material; 3, a solid polymer electrolyte membrane; 4, an anode terminal provided on the anode 1; 5, a cathode terminal provided on the cathode 2; 6, a DC power supply; 8, an electrochemical device conjunctive body formed by thermo compression bonding of the anode 1 and the cathode 2 which are disposed on the front and back surfaces of the solid polymer electrolyte membrane 3; 11, for example, an NPN-type transistor; 12, an emitter of the transistor 11; 13, abase; 14, a collector; 15, an electric current flowing between the emitter 12 and the base 13; 16, a collector current flowing into the collector 14; and 17, a resistor. The electrochemical device conjunctive body 8 is connected between the higher potential output side of the DC power supply 6 and the collector 14 of the transistor 11, with the emitter 12 connected to the other output side of the DC power supply 6. In addition, the resistor 17 is connected between the higher potential output side of the DC power supply 6 and the base 13 of the transistor 11.

[0067] In this embodiment, a unit is constituted by the transistor 11 and the resistor 17 so that the unit makes control to make a predetermined constant electric current flow into the electrochemical device conjunctive body 8.

[0068] The reference numeral 102 represents a resistor which is connected in parallel with the resistor 17 between the lower potential output side of the DC power supply 6 and the base 13 of the transistor 11. Thus, the resistor 102 constitutes a circuit A. The reference numeral 101 represents a circuit (for example, a timer) having a function to bring the circuit A into a closed state only for a predetermined time span. Working with the intermittent operation of the electrochemical device conjunctive body 8, the operation to bring the circuit A into the closed state is repeated only for the predetermined time span when the operation of gas conversion is restarted. The reference numeral 103 represents an electric current flowing into the circuit A.

[0069] In this embodiment, a unit is constituted by the resistor 102 and the timer 101, so that the unit makes control to make an electric current flow into the electrochemical device conjunctive body 8 during a predetermined period of time after the start of the operation of gas conversion, the electric current being larger than that after the predetermined period of time passes.

[0070] In addition, a unit is constituted by the transistor 11, the resistors 17 and 102, and the timer 101, so that the unit makes control in a manner such that an electric current larger than a predetermined constant electric current flows into the electrochemical device conjunctive body 8 during a predetermined period of time after the start of the operation of gas conversion, and then the predetermined constant electric current flows.

[0071] Next, description will be made on the operation.

[0072] First, description will be made on the steady operation after a predetermined period of time passes since the operation of gas conversion is started. In the steady operation, the timer 101 is in an opened state. In the circuit of FIG. 1, the electric current 15 having a value obtained by dividing the output voltage of the DC power supply 6 chiefly by the resistance value of the resistor 17 flows between the emitter 12 and the base 13 of the transistor 11. This current becomes constant without having any influence of the properties of the electrochemical device conjunctive body 8 provided on the collector 14 side of the transistor 11. Therefore, the constant current 16 obtained by multiplying the current 15 flowing between the emitter 12 and the base 13 by the amplification factor of the transistor 11 flows into the collector 14. Thus, a constant current flows into the electrochemical device conjunctive body 8. Incidentally, the value of the current supplied to the electrochemical device conjunctive body 8 can be set by properly selecting the transistor 11, the voltage value of the DC power supply 6 and the resistance value of the resistor 17.

[0073] Thus, the circuit of FIG. 1 allows a constant current to flow into the electrochemical device conjunctive body 8. Even if the outside air environment such as humidity changes on a large scale, the electrochemical device conjunctive body 8 can obtain a stable quantity of converted gas without generating excessive gas.

[0074] Next, description will be made on the time when the operation of gas conversion is started. In the circuit of FIG. 1, when the electrochemical device conjunctive body 8 is operated intermittently to restart the operation of gas conversion, the timer 101 is operated to bring the circuit A into the closed state only for a predetermined time span. Then, a base current in which the current flowing through the resistor 17 and the current 103 flowing through the resistor 102 are linked up flows into the base 13 of the transistor 11. As a result, a larger current flows into the electrochemical device conjunctive body 8 than that when the base current is only a current flowing through the resistor 17. After that, when the timer 101 switches to an opened state, only the current 15 flowing through the resistor 17 flows into the base 13 of the transistor 11. As described above, a predetermined constant current flows into the electrochemical device conjunctive body 8 by properly selecting the transistor 11, the voltage value of the DC power supply 6 and the resistance value of the resistor 17.

[0075] Thus, according to the circuit of FIG. 1, in the intermittent operation in the high humidity environment, the electric current flowing into the electrochemical device conjunctive body 8 can be increased only for a predetermined time span after the start of the operation of gas conversion. The load voltage on the electrochemical device conjunctive body 8 can be enhanced so that the quantity of generated ozone can be prevented from being lowered significantly at the start of the operation of gas conversion. In addition, after that, a predetermined constant electric current smaller than the current at the start of the operation of gas conversion can be supplied. Even if there is a change in the environmental conditions such as humidity, the quantity of generated ozone can be obtained efficiently and stably without generating excessive gas.

[0076] Next, description will be made on the operation of this embodiment along a specific example while comparison is made with a circuit shown in FIG. 2 which does not have the circuit A. In the constant current circuit shown in FIG. 2 which does not have the circuit A, setting is done so that the voltage (V0) of the DC power supply 6 is 5 V, and the predetermined constant current flowing into the electrochemical device conjunctive body 8 (the electrochemical reaction area formed by the anode and the cathode opposed to each other is 2.4 cm2) is 25 mA/cm2. An operating cycle of 2-hour running and 22-hour suspension is repeated in the high humidity environment of the temperature 25° C. and the relative humidity 90% so as to generate ozone. In this case, the load voltage (Vd) on the electrochemical device conjunctive body 8 is lower than 2 V at the start of the operation of gas conversion, and the quantity of generated ozone is lowered significantly.

[0077] On the other hand, in the circuit of FIG. 1 according to this embodiment, the timer 101 is set so that the circuit A would be brought into the closed state only for 5 minutes after the start of the operation of gas conversion. The resistor 102 is set so that the current 103 flowing into the circuit A would be twice as large as the current flowing through the resistor 17. As a result, a constant current of 75 mA/cm2 flowed into the electrochemical device conjunctive body 8 for 5 minutes after the start of the operation of gas conversion. After that, the timer 101 switched to the opened state so that only the current flowing through the resistor 17 flowed into the base 13 of the transistor 11. Thus, a constant current of 25 mA/cm2 flowed into the electrochemical device conjunctive body 8.

[0078] As a result, in the intermittent operation in the high humidity environment, the quantity of generated ozone is prevented from lowing significantly at the start of the operation of gas conversion, while a stable quantity of generated ozone could be obtained during the operation of gas conversion. In addition, since a predetermined constant current (25 mA/cm2) is supplied in this embodiment, the quantity of generated ozone could be kept efficient and more stable without generating excessive gas even if there is a change in the outside air environment such as humidity.

[0079] Incidentally, although FIG. 1 shows the case where an NPN transistor is used as the transistor 11, a PNP transistor may be used. In this case, there is some difference in how to connect, but similar effects can be obtained.

[0080] (Embodiment 2)

[0081] Although description in Embodiment 1 is made on the case where the transistor 11 is used, similar effects can be obtained using a resistor in place of the transistor 11.

[0082] FIG. 3 is a diagram for explaining the configuration of an electrolytic gas converter according to Embodiment 2 of the invention. In FIG. 3, the reference numerals 105 and 106 represent resistors respectively. The resistor 106 is connected in series between the anode of the DC power supply 6 and the anode 1 of the electrochemical device conjunctive body 8. That is, there is shown a characteristic as follows. When a large current attempts to flow into the electrochemical device conjunctive body 8, the load voltage (Vd) on the electrochemical device conjunctive body 8 is lowered by the resistor 106. On the contrary, when the current flowing into the electrochemical device conjunctive body 8 is lowered, the load voltage (Vd) on the electrochemical device conjunctive body 8 is increased by the resistor 1106. Accordingly, by setting the resistor 106 having a proper resistance value in advance, a current outputted from the DC power supply 6 to the electrochemical device conjunctive body 8 is made constant. Thus, generation of excessive ozone is prevented even if the humidity of the outside air is high.

[0083] In this embodiment, the circuit A constituted by the timer 101 and the resistor 105 is connected in parallel with the resistor 106 in the circuitry. A unit is constituted by the resistor 105 and the timer 101 so that the unit makes control to make a current flow for a predetermined period of time after the start of the operation of gas conversion, the current being larger than that after the predetermined period of time passes.

[0084] Next, description will be made on the operation. In the circuit of FIG. 3, the electrochemical device conjunctive body 8 is operated intermittently. When the operation of gas conversion is restarted, the timer 101 is operated to bring the circuit into the closed state only for a predetermined time span. In this case, an electric current has a value which is obtained in a manner so that the voltage obtained by subtracting the load voltage (Vd) on the electrochemical device conjunctive body 8 from the output voltage (V0) of the DC power supply 6 is divided by the parallel resistance constituted by the resistors 105 and 106. The thus obtained electric current flows into the electrochemical device conjunctive body 8. After that, when the timer 101 switches to the opened state, a current has a value obtained in a manner so that the voltage obtained by subtracting the load voltage (Vd) on the electrochemical device conjunctive body 8 from the output voltage (V0) of the DC power supply 6 is divided by the resistance value of the resistor 106. The thus obtained current flows into the electrochemical device conjunctive body 8.

[0085] Here, the resistance values of the resistors 105 and 106 are set so that the current flowing into the electrochemical device conjunctive body 8 will be approximately 75 mA/cm2 when the timer 101 is in the closed state, while the current flowing into the electrochemical device conjunctive body 8 will be approximately 25 mA/cm2 when the timer 101 is in the opened state.

[0086] In this case, because the change of the load voltage on the electrochemical device conjunctive body 8 has a complicated relationship to the current, the stability of the quantity of generated ozone is inferior to that in the circuit of FIG. 1. However, according to the circuit of FIG. 3, there is an advantage that the number of parts in the circuit is small so that the cost is inexpensive.

[0087] (Embodiment 3)

[0088] FIG. 4 is a diagram for explaining the configuration of an electrolytic gas converter according to Embodiment 3 of the invention.

[0089] In FIG. 4, the reference numeral 31 represents an AC input such as a commercial power source; 32, a rectifying circuit for constituting a full-wave rectifying circuit or the like; 33, a voltage smoothing capacitor; 34, a charge quantity limiting capacitor; and 35, a voltage limiting Zener diode. The charge quantity limiting capacitor 34 is connected in series between the AC input 31 and the rectifying circuit 32. The voltage smoothing capacitor 33 and the voltage limiting Zener diode 35 are connected in parallel with the electrochemical device conjunctive body 8.

[0090] In this embodiment, a unit is constituted by the rectifying circuit 32, the capacitors 33 and 34, and the voltage limiting Zener diode 35, so that the unit makes control to make a predetermined constant current flow into the electrochemical device conjunctive body 8.

[0091] The reference numeral 112 represents a capacitor, which is connected in parallel with the charge quantity limiting capacitor 34 between the AC input 31 and the rectifying circuit 32. Thus, a circuit B is constituted. The reference numeral 111 represents a circuit (such as a timer) having a function to bring the circuit B into the closed state only for a predetermined time span. Working with the intermittent operation of the electrochemical device conjunctive body 8, the operation to bring the circuit B into the closed state is repeated only for the predetermined time span when the operation of gas conversion is restarted.

[0092] In this embodiment, a unit is constituted by the capacitor 112 and the timer 111, so that the unit makes control to make an electric current flow into the electrochemical device conjunctive body 8 during a predetermined period of time after the start of the operation of gas conversion, the electric current being larger than that after the predetermined period of time passes.

[0093] Next, description will be made on the operation.

[0094] First, description will be made on the steady operation after the predetermined period of time passes since the operation of gas conversion is started. In the steady operation, the timer 111 is in the opened state. In the circuit of FIG. 4, when the AC input 31 is a 100 V commercial power source, an effective voltage of about 100 V is applied to the opposite ends of the charge quantity limiting capacitor 34 at intervals of 50 or 60 cycles. The quantity of charges corresponding to the change of voltage is transmitted to the rectifying circuit 32. Therefore, a current supplied to the rectifying circuit 32 is determined by the capacitance value of the charge quantity limiting capacitor 34. The current flowing into the electrochemical device conjunctive body 8 can be kept constant by setting the capacitance value of the charge quantity limiting capacitor 34 to be constant. At this time, by connecting the voltage limiting Zener diode 35 in parallel with the electrochemical device conjunctive body 8, the voltage applied to the electrochemical device conjunctive body 8 is restrained from being excessive.

[0095] Thus, according to the circuit of FIG. 4, the number of parts is reduced even in the case of an AC input, and a constant current can be made to flow into the electrochemical device conjunctive body 8. Thus, the electrochemical device conjunctive body 8 can obtain a stable quantity of converted gas without generating excessive gas even if there is a great change in the outside air environment such as humidity.

[0096] Next, description will be made on the time when the operation of gas conversion is started. In the circuit of FIG. 4, when the electrochemical device conjunctive body 8 is operated intermittently to restart the operation of gas conversion, the timer 111 is operated to bring the circuit into the closed state for a predetermined time span. In this case, a constant current determined by the parallel capacitance value of the capacitors 34 and 112 is supplied to the electrochemical device conjunctive body 8. After that, when the timer 111 switches to the opened state, a constant current determined by the capacitance value of only the capacitor 34 is supplied to the electrochemical device conjunctive body 8.

[0097] Thus, according to the circuit of FIG. 4, a constant current flowing into the electrochemical device conjunctive body 8 can be increased only for a predetermined period of time after the start of the operation of gas conversion. Thus, the load voltage on the electrochemical device conjunctive body 8 can be enhanced so that the quantity of generated gas can be prevented from being lowered significantly at the start of the operation of gas conversion. In addition, after that, a predetermined constant electric current smaller than the current at the start of the operation of gas conversion can be supplied. Even if there is a change in the environmental conditions such as humidity, the quantity of generated ozone can be obtained efficiently and stably without generating excessive gas.

[0098] Next, description will be made on the operation of this embodiment along a specific example while comparison is made with a circuit shown in FIG. 5 which does not have the circuit B. In the constant current circuit shown in FIG. 5 which does not have the circuit B, the capacitance value of the capacitor 34 is set so that the AC input is 100 V at 60 cycles, the voltage applied to the electrochemical device conjunctive body 8 by the voltage limiting Zener diode 35 is 5 V, and the constant current flowing into the electrochemical device conjunctive body 8 (the electrochemical reaction area formed by the anode and the cathode opposed to each other is 2.4 cm2) is 25 mA/cm2. An operating cycle of 2-hour running and 22-hour suspension is repeated in the high humidity environment of the temperature 25° C. and the relative humidity 90% so as to generate ozone. In this case, the load voltage on the electrochemical device conjunctive body 8 is lower than 2 V at the start of the operation of gas conversion, and the quantity of generated ozone is lowered significantly.

[0099] On the other hand, in the circuit of FIG. 4 according to this embodiment, the timer 111 is set so that the circuit B would be in the closed state for 5 minutes after the start of the operation of gas conversion. The charge capacitance values of the capacitors 34 and 112 are set so that the current flowing into the electrochemical device conjunctive body 8 would be approximately 75 mA/cm2 when the timer 111 is in the closed state, while the predetermined constant value flowing into the electrochemical device conjunctive body 8 would be approximately 25 mA/cm2 when the timer 111 is brought into the opened state.

[0100] As a result, the quantity of generated ozone is prevented from being lowered significantly at the start of the operation of gas conversion, while a stable quantity of generated ozone could be obtained during the operation of gas conversion. In addition, since a predetermined constant current (25 mA/cm2) is made to flow in this embodiment, the quantity of generated ozone could be kept efficient and more stable without generating excessive gas even if there is a change in the outside air environment such as humidity.

[0101] Incidentally, in the respective Embodiments 1 to 3, description is made on the case where the timers 101 and 111 are in the closed state only for 5 minutes. However, the duration of the closed state of the timers 101 and 111 may be longer or shorter. In this case, when the duration of the closed state of the timers 101 and 111 is longer, the time taken to reach a predetermined voltage becomes longer, but there is an advantage that the current made to flow into the electrochemical device conjunctive body 8 can be reduced. On the other hand, when the duration of the closed state of the timers 101 and 111 is shorter, it is necessary to increase the current supplied to the electrochemical device conjunctive body 8. However, there is an advantage that the time taken to reach a predetermined voltage becomes shorter.

[0102] In addition, in the respective Embodiments 1 to 3, description is made on the case where there is provided a unit for making control so that a constant current larger than a predetermined constant current is made to flow into the electrochemical device conjunctive body 8 for a predetermined period of time after the start of the operation of gas conversion. However, it will go well if the current is larger than the predetermined constant current, and the current does not have to be constant.

[0103] Furthermore, description is made on the case where there is provided a unit for making control so that a predetermined constant current is supplied after the predetermined period of time passes since the start of the operation of gas conversion. However, when there is little change in the environmental conditions such as humidity, the unit for making control so that a constant current is supplied may be not required.

[0104] (Embodiment 4)

[0105] FIG. 6 is a diagram for explaining the configuration of an electrolytic gas converter according to Embodiment 4 of the invention.

[0106] In FIG. 6, the reference numeral 300 represents a timer which can repeat a conduction state and a non-conduction state in a predetermined cycle within a predetermined operating time (for example, a timer constituted by a timer for determining the predetermined operating time, a vibrator for determining the cycle with in the predetermined operating time, and a vibrator for determining the conduction duration in the predetermined cycle).

[0107] In this embodiment, the timer 300 which can repeat a conduction state and a non-conduction state in a predetermined cycle within a predetermined operating time is used in place of the timer 101 which brings the circuit A into the closed state only for a predetermined time span as described in Embodiment 1. This embodiment is different from Embodiment 1 at such a point, but the other configuration is similar to that in FIG. 1 shown in Embodiment 1.

[0108] In this embodiment, a unit is constituted by the resistor 102 and the timer 300, so that the unit makes control to make an electric current flow into the electrochemical device conjunctive body 8 periodically for a predetermined period of time after the start of the operation of gas conversion, the electric current being larger than that after the predetermined period of time passes.

[0109] In addition, a unit is constituted by the transistor 11, the resistors 17 and 102, and the timer 300 so that the unit makes control to supply a predetermined constant current to the electrochemical device conjunctive body 8 after a current larger than the predetermined constant current is supplied periodically for a predetermined period of time after the start of the operation of gas conversion.

[0110] Next, description will be made on the operation, chiefly concerning the different point from Embodiment 1. In the circuit of FIG. 6, when the electrochemical device conjunctive body 8 is operated intermittently to restart the operation of gas conversion, the timer 300 is operated so that the circuit A repeats a cycle of a closed state and an opened state with a predetermined time span for a predetermined period of time. At this time, when the circuit A is in the closed state, a base current in which a current flowing through the resistor 17 and a current 103 flowing through the resistor 102 are linked up flows into the base 13 of the transistor 11. As a result, a larger current flows into the electrochemical device conjunctive body 8 than that when the base current is only a current flowing through the resistor 17. On the other hand, when the circuit A is in the opened state, only a current 15 flowing through the resistor 17 flows into the base 13 of the transistor 11. As a result, a large current and a small current flow into the electrochemical device conjunctive body 8 periodically during the operation of the timer 300. After that, when the timer 300 gets into suspension (opened state), the current flowing into the base 13 of the transistor 11 is only the current 15 flowing through the resistor 17. Thus, a predetermined constant current flows into the electrochemical device conjunctive body 8 by properly selecting the transistor 11, the voltage value of the DC power supply 6 and the resistance value of the resistor 17.

[0111] Thus, according to the circuit of FIG. 6, in the intermittent operation in the high humidity environment, a current flowing into the electrochemical device conjunctive body 8 can be increased periodically only for a predetermined time span since the operation of gas conversion is started. Thus, the quantity of generated gas is prevented from being lowered significantly at the start of the operation of gas conversion. In addition, after that, a predetermined constant current smaller than the current at the start of the operation of gas conversion can be supplied. Even if there is a change in the environmental conditions such as humidity, the quantity of generated ozone can be obtained efficiently and stably without generating excessive gas.

[0112] Further, in this embodiment, the current flowing into the electrochemical device conjunctive body 8 is increased periodically only for a predetermined time span since the operation of gas conversion is started. Thus, there can be also obtained an effect that the quantity of generated gas can be controlled for the predetermined time span more carefully than that when a constant current is supplied during a predetermined time span as described in Embodiment 1.

[0113] Next, description will be made on the operation of this embodiment along a specific example while comparison is made with the case shown in FIG. 2 which does not have the circuit A. In the constant current circuit shown in FIG. 2 which does not have the circuit A, setting is done so that the voltage (V0) of the DC power supply 6 is 5 V, and a predetermined constant current flowing into the electrochemical device conjunctive body 8 (the electrochemical reaction area formed by the anode and the cathode opposed to each other is 2.4 cm2) is 25 mA/cm2. An operating cycle of 2-hour running and 22-hour suspension is repeated in the high humidity environment of the temperature 25° C. and the relative humidity 90% so as to generate ozone. In this case, the load voltage (Vd) on the electrochemical device conjunctive body 8 is lower than 2 V at the start of the operation of gas conversion, and the quantity of generated ozone is lowered significantly.

[0114] On the other hand, in the circuit of FIG. 6 according to this embodiment, for example, setting is done so that the timer 300 would operate for 30 minutes after the start of the operation of gas conversion, while a cycle in which the circuit A is in the closed state for 2 minutes and in the opened state for 8 minutes would be repeated three times. At this time, when the circuit A is in the closed state, a constant current of 75 mA/cm2 flowed into the electrochemical device conjunctive body 8. When the circuit A is in the opened state, a constant current of 25 mA/cm2 flowed. After the timer 300 stopped its operation when 30 minutes passes, the current flowing into the base 13 of the transistor 11 is the current flowing only through the resistor 17. Thus, a constant current of 25 mA/cm2 flowed into the electrochemical device conjunctive body 8.

[0115] As a result, in the intermittent operation in the high humidity environment, the quantity of generated gas is prevented from being lowered significantly at the start of the operation of gas conversion. In addition, during the operation of gas conversion, even if there is a change in the outside air environment such as humidity, the quantity of generated ozone could be kept efficient and stable without generating excessive gas.

[0116] Incidentally, in the above embodiment, description is made on the case where the timer 300 which could repeat a conduction state and a non-conduction state in a predetermined cycle within a predetermined operating time is used in the electrolytic gas converter according to Embodiment 1 shown in FIG. 1, in place of the timer 101 for bringing the circuit A into the closed state only for a predetermined time span. However, the timer 300 which can repeat a conduction state and a non-conduction state in a predetermined cycle within a predetermined operating time may be used in the electrolytic gas converter according to Embodiment 2 or 3 shown in FIG. 3 or 4, in place of the timer 101 or 111 for bringing the circuit A into the closed state only for a predetermined time span. Also in this case, similar effects can be obtained.

[0117] (Embodiment 5)

[0118] FIG. 7 is a diagram for explaining the configuration of an electrolytic gas converter according to Embodiment 5 of the invention.

[0119] In FIG. 7, the reference numerals 121 and 122 represent switches respectively; 123, a constant voltage circuit for generating a constant voltage; and 124 and 125, resistors respectively.

[0120] In this embodiment, a unit is constituted by the switches 121 and 122, the constant voltage circuit 123, and the resistors 124 and 125 so that the unit makes control in a manner such that a voltage low enough or an electric current small enough not to generate ozone (not to convert moisture into gas) is applied or conducted to the electrochemical device conjunctive body 8 during the suspension of operation of gas conversion.

[0121] In addition, a unit is constituted by a transistor 11 and resistors 17 and 124 so that the unit makes control to supply a predetermined constant current to the electrochemical device conjunctive body 8 during the operation of gas conversion.

[0122] Furthermore, a unit is constituted by the transistor 11, the resistors 17, 124 and 125, the switches 121 and 122, and the constant voltage circuit 123, so that the unit makes control in a manner such that a constant current is supplied to the electrochemical device conjunctive body 8 during the operation of gas conversion, while a voltage low enough or an electric current small enough not to generate ozone (not to convert moisture into gas) is applied or conducted to the electrochemical device conjunctive body 8 during the suspension of operation of gas conversion.

[0123] Next, description will be made on the operation. In the circuit of FIG. 7, first when both the switches 121 and 122 are brought into the closed state at the time of the suspension of the operation of gas conversion of the electrochemical device conjunctive body 8, a voltage supplied from the constant voltage circuit 123 is applied to the electrochemical device conjunctive body 8 during the suspension of the operation of gas conversion. At this time, the voltage supplied from the constant voltage circuit 123 is set to a voltage low enough not to generate ozone. Thus, a small current flows into the electrochemical device conjunctive body 8.

[0124] Next, when both the switches 121 and 122 are brought into the opened state in order to restart the operation of gas conversion of the electrochemical device conjunctive body 8, the voltage supply from the constant voltage circuit 123 to the electrochemical device conjunctive body 8 is suspended. Thus, a predetermined constant current flows through the transistor 11 in the same manner as in the circuit shown in FIG. 2.

[0125] In such a manner, according to the circuit of FIG. 7, a voltage low enough not to generate ozone (not to convert moisture into gas) is applied during the suspension of the operation of gas conversion. Thus, a small current flows into the electrochemical device conjunctive body 8 so that the solid polymer electrolyte membrane 3 of the electrochemical device conjunctive body 8 is prevented from retaining excessive moisture. Accordingly, when the operation of gas conversion is restarted, a constant current can be made to flow into the electrochemical device conjunctive body 8 in the state where the load voltage on the electrochemical device conjunctive body 8 is prevented from being lowered significantly. As a result, in the intermittent operation in the high humidity environment, the quantity of generated ozone is prevented from being lowered significantly at the start of the operation of gas conversion. On the other hand, during the operation of gas conversion, the quantity of generated ozone can be obtained efficiently and stably without generating excessive gas even if there is a change in the environmental conditions such as humidity.

[0126] Next, description will be made on the operation of this embodiment along a specific example. Incidentally, the conditions of the intermittent operation and the conditions of the outside air environment are similar to those in Embodiment 1. In the circuit of FIG. 7, when the electrochemical device conjunctive body 8 is in the suspension of the operation of gas conversion, both the switches 121 and 122 are brought into the closed state so that a voltage of 1.5 V is supplied from the constant voltage circuit 123 to the electrochemical device conjunctive body 8. At that time, a current ranging from 10 mA/cm2 to 15 mA/cm2 flowed into the electrochemical device conjunctive body 8, but the generation of ozone is not recognized.

[0127] Next, the switches 121 and 122 are brought into the opened state in order to start the operation of gas conversion of the electrochemical device conjunctive body 8. Thus, a constant current of 25 mA/cm2 is made to flow through the transistor As a result, the quantity of generated ozone is prevented from being lowered significantly at the start of the operation of gas conversion, while a stable quantity of generated ozone could be obtained during the operation of gas conversion. In addition, since a predetermined constant current (25 mA/cm2) is made to flow during the operation of gas conversion, the quantity of generated ozone could be kept efficient and more stable without generating excessive gas even if there is a change in the outside air environment such as humidity.

[0128] Incidentally, a low voltage of, for example, 1.5 V is supplied from the constant voltage circuit 123 to the electrochemical device conjunctive body 8 during the suspension of the operation of gas conversion in FIG. 7. However, as shown in FIG. 8, a constant voltage diode 127 may be used in place of the constant voltage circuit 123.

[0129] In this case, the resistor 124 is set so that a current ranging from 10 mA/cm2 to 15 mA/cm2 will flow into the electrochemical device conjunctive body 8 when the switch 121 is in the closed state, while a constant current of 25 mA/cm2 will flow into the electrochemical device conjunctive body 8 when the switch 121 is in the opened state.

[0130] In the circuit of FIG. 8, the constant voltage diode 127 is designed to be made conductive if the switch 121 is brought into the closed state during the suspension of the operation of gas conversion, and, for example, the voltage exceeds 1.5 V. Thus, a current ranging from 10 mA/cm2 to 15 mA/cm2 can be made to flow into the electrochemical device conjunctive body 8 while the voltage is clamped to be 1.5 V. Next, when the operation of gas conversion is restarted, the switch 121 is brought into the opened state. Thus, a constant current of 25 mA/cm2 can be made to flow into the electrochemical device conjunctive body 8 through the transistor 11. In such a manner, according to the circuit of FIG. 8, effects similar to those in the circuit of FIG. 7 can be obtained with a simple circuit.

[0131] In addition, although an example using the constant voltage diode 127 is shown in FIG. 8, a Zener diode making conduction with a constant voltage similar to that in the diode 127 may be used. Also in this case, similar effects can be obtained.

[0132] (Embodiment 6)

[0133] Although description in Embodiment 5 is made on the case where the transistor 11 is used, similar effects can be also obtained when a resistor is used in place of the transistor 11.

[0134] FIG. 9 is a diagram for explaining the configuration of an electrolytic gas converter according to Embodiment 6 of the invention. In FIG. 9, the reference numeral 128 represents a resistor.

[0135] A resistor 128 is connected in series between the anode of the DC power supply 6 and the anode 1 of the electrochemical device conjunctive body 8. That is, there is shown a characteristic as follows. When a large current attempts to flow into the electrochemical device conjunctive body 8, the load voltage (Vd) on the electrochemical device conjunctive body 8 is lowered by the resistor 128. On the contrary, when the current flowing into the electrochemical device conjunctive body 8 is lowered, the load voltage (Vd) on the electrochemical device conjunctive body 8 is increased by the resistor 128. Accordingly, by setting the resistor 128 having a proper resistance value in advance, a current supplied from the DC power supply 6 to the electrochemical device conjunctive body 8 is made constant. Thus, generation of excessive ozone is prevented even if the humidity of the outside air is high.

[0136] In this embodiment, in the circuitry, a switch 122 is disposed between the resistor 128 and the electrochemical device conjunctive body 8, and a circuit constituted by a switch 121 and a constant voltage circuit 123 is connected in parallel with the electrochemical device conjunctive body 8. A unit is constituted by the switches 121 and 122 and the constant voltage circuit 123, so that the unit makes control in a manner such that a voltage low enough or an electric current small enough not to generate ozone (not to convert moisture into gas) is applied or conducted to the electrochemical device conjunctive body 8 during the suspension of operation of gas conversion.

[0137] Next, description will be made on the operation. In the circuit of FIG. 9, when the switches 121 and 122 are brought into the closed state and the opened state respectively at the time of the suspension of the operation of gas conversion of the electrochemical device conjunctive body 8, there is no supply from the DC power supply 6 and a voltage supplied from the constant voltage circuit 123 is applied to the electrochemical device conjunctive body 8. Incidentally, when the voltage supplied from the constant voltage circuit 123 is set to a voltage low enough not to generate ozone, for example, to a voltage of 1.5 V, a small current ranging from 10 mA/cm2 to 15 mA/cm2 flows into the electrochemical device conjunctive body 8 so that the load voltage on the electrochemical device conjunctive body 8 is prevented from being lowered significantly, in the same manner as in the case of FIG. 7.

[0138] Next, when the switches 121 and 122 are brought into the opened state and the closed state respectively in order to restart the operation of gas conversion of the electrochemical device conjunctive body 8, the voltage supply from the constant voltage circuit 123 to the electrochemical device conjunctive body 8 is suspended. Thus, a current flows from the DC power supply 6 through the resistor 128 to the electrochemical device conjunctive body 8. Incidentally, the resistance value of the resistor 128 is set so that the current flowing into the electrochemical device conjunctive body 8 is approximately 25 mA/cm2.

[0139] In this case, the change of the load voltage on the electrochemical device conjunctive body 8 is not proportional to the current but complicated. Thus, the stability of the quantity of generated ozone is inferior to that in the circuit of FIG. 7. According to the circuit of FIG. 9, however, there is an advantage that the number of parts in the circuit is reduced so that the cost is reduced.

[0140] (Embodiment 7)

[0141] FIG. 10 is a diagram for explaining the configuration of an electrolytic gas converter according to Embodiment 7 of the invention.

[0142] In FIG. 10, the reference numerals 131 and 132 represent switches respectively. The switch 132 is put into the opened state when the switch 131 is in the closed state, while the switch 132 is put into the closed state when the switch 131 is in the opened state. The reference numeral 133 represents a constant voltage circuit.

[0143] In this embodiment, a unit is constituted by the switches 131 and 132 and the constant voltage circuit 133, so that the unit makes control in a manner such that a voltage low enough or an electric current small enough not to generate ozone (not to convert moisture into gas) is applied or conducted to the electrochemical device conjunctive body 8 during the suspension of operation of gas conversion.

[0144] In addition, a unit is constituted by the rectifying circuit 32, the capacitors 33 and 34, and the voltage limiting Zener diode 35, so that the unit makes control to supply a predetermined constant current to the electrochemical device conjunctive body 8 during the operation of gas conversion.

[0145] Next, description will be made on the operation. In the circuit of FIG. 10, when the switches 131 and 132 are brought into the closed state and the opened state respectively at the time of the suspension of the operation of gas conversion of the electrochemical device conjunctive body 8, there is no voltage supply from the AC power source 31 and a voltage supplied from the constant voltage circuit 133 is applied to the electrochemical device conjunctive body 8 in the suspension of the operation of gas conversion. At this time, the voltage supplied from the constant voltage circuit 133 is set to a voltage low enough not to generate ozone. Thus, a small current flows into the electrochemical device conjunctive body 8.

[0146] Next, when the switches 131 and 132 are brought into the opened state and the closed state respectively at the start of the operation of gas conversion of the electrochemical device conjunctive body 8, the voltage supply from the constant voltage circuit 133 to the electrochemical device conjunctive body 8 is suspended. Thus, a predetermined constant current determined by the capacitor 34 is supplied during the operation of gas conversion.

[0147] In such a manner, according to the circuit of FIG. 10, a voltage low enough not to generate ozone is applied during the suspension of the operation of gas conversion so that a small current flows into the electrochemical device conjunctive body 8. Accordingly, a constant current can be supplied to the electrochemical device conjunctive body 8 in the state where the load voltage on the electrochemical device conjunctive body 8 is prevented from being lowered significantly. As a result, the quantity of generated ozone is prevented from being lowered significantly at the start of the operation of gas conversion. In addition, during the operation of gas conversion, the quantity of generated ozone can be obtained efficiently and stably without generating excessive gas even if there is a change in the environmental conditions such as humidity.

[0148] Next, description will be made on the operation of this embodiment along a specific example while comparison is made with the circuit shown in FIG. 5 which does not have the switches 131 and 132 and the constant voltage circuit 133. Incidentally, the conditions of the intermittent operation and the conditions of the outside air environment are similar to those in Embodiment 1 or 2. In the constant current circuit shown in FIG. 5 which does not have the switches 131 and 132 and the constant voltage circuit 133, the capacitance value of the capacitor 34 is set so that the AC input is 100 V at 60 cycles, the voltage applied to the electrochemical device conjunctive body 8 by the voltage limiting Zener diode 35 is 5 V, and a constant current flowing into the electrochemical device conjunctive body 8 is 25 mA/cm2. In this case, the load voltage on the electrochemical device conjunctive body 8 is lower than 2 V at the start of the operation of gas conversion, and the quantity of generated ozone is lowered significantly.

[0149] On the other hand, in the circuit of FIG. 10 according to this embodiment, the switches 131 and 132 are brought into the closed state and the opened state respectively at the time of the suspension of the operation of gas conversion of the electrochemical device conjunctive body 8. Thus, a voltage of 1.5 V is supplied from the constant voltage circuit 133 to the electrochemical device conjunctive body 8. At this time, a small current ranging from 10 mA/cm2 to 15 mA/cm2 flowed into the electrochemical device conjunctive body 8, but the generation of ozone is not recognized.

[0150] Next, the switches 131 and 132 are brought into the opened state and the closed state respectively in order to start the operation of gas conversion of the electrochemical device conjunctive body 8. The voltage supply from the constant voltage circuit 133 to the electrochemical device conjunctive body 8 is suspended. Thus, a constant current of 25 mA/cm2 determined by the capacitor 34 is supplied.

[0151] As a result, the quantity of generated ozone is prevented from being lowered significantly at the start of the operation of gas conversion. On the other hand, during the operation of gas conversion, a stable quantity of generated ozone could be obtained. In addition, since a predetermined constant current (25 mA/cm2) is supplied in this embodiment, the quantity of generated ozone could be kept efficient and more stable without generating excessive gas even if there is a change in the outside air environment such as humidity.

[0152] Incidentally, in FIG. 10, a low voltage, for example, 1.5 V is supplied to the electrochemical device conjunctive body 8 by the constant voltage circuit 133 during the suspension of the operation of gas conversion. However, as shown in FIG. 11, a constant voltage diode 137 may be used in place of the constant voltage circuit 133. In FIG. 11, the reference numeral 134 represents a capacitor disposed in parallel with the capacitor 34, constituting a circuit B together with the switch 132.

[0153] In this case, the capacitance value of the capacitor 34 is set so that a current ranging from 10 mA/cm2 to 15 mA/cm2 will be supplied to the electrochemical device conjunctive body 8 by the capacitor 34. In addition, the capacitance value of the capacitor 134 is set so that a constant current of 25 mA/cm2 will be supplied to the electrochemical device conjunctive body 8 by the parallel capacitance of the capacitors 34 and 134.

[0154] In the circuit of FIG. 11, the diode 137 is designed to make conduction if the voltage exceeds 1.5 V by way of example when the switches 131 and 132 are brought in the closed state and the opened state respectively during the suspension of the operation of gas conversion. Thus, a current ranging from 10 mA/cm2 to 15 mA/cm2 can be supplied to the electrochemical device conjunctive body 8 while the voltage is clamped to be 1.5 V. Next, when the operation of gas conversion is restarted, the switches 131 and 132 are brought into the opened state and the closed state respectively. Thus, a constant current of 25 mA/cm2 can be supplied to the electrochemical device conjunctive body 8 by the parallel capacitance of the capacitors 34 and 134.

[0155] In such a manner, according to the circuit of FIG. 11, effects similar to those in the circuit of FIG. 10 can be also obtained without using the constant voltage circuit 133.

[0156] In addition, although the case using the constant voltage diode 137 is shown in FIG. 11, a Zener diode making conduction with a constant voltage similar to that in the diode 137 may be used. Also in this case, similar effects can be obtained.

[0157] In the respective Embodiments 5 to 7, description is made on the case where a voltage of 1.5 V is applied to the electrochemical device conjunctive body 8 during the suspension of the operation of gas conversion. However, the voltage is not limited to this value, but it will go well if the voltage is low enough not to result in converting moisture into gas. In the case of an ozone generator, it is desired that the voltage is lower than 2 V. In this case, it is desired that a current smaller than 20 mA/cm2 is supplied to the electrochemical device conjunctive body 8.

[0158] (Embodiment 8)

[0159] FIG. 12 is a diagram for explaining the configuration of an electrolytic gas converter according to Embodiment 8 of the invention.

[0160] In FIG. 12, the reference numeral 141 represents a switch; 142, an amplifier; 143, a comparator; 144 and 145, resistors; 146, an inverter; and 147 and 148, resistors.

[0161] In this embodiment, a unit is constituted by the resistors 145, 147 and 148, the switch 141, the amplifier 142, the comparator 143 and the inverter 146, so that the unit makes control to supply an electric current to the electrochemical device conjunctive body 8 in the case where a voltage applied to the electrochemical device conjunctive body 8 is lower than a predetermined voltage, the electric current being larger than that in the case where the voltage is higher than the predetermined voltage.

[0162] In addition, a unit is constituted by the transistor 11 and the resistors 17 and 144 so that the unit makes control to supply a predetermined constant current to the electrochemical device conjunctive body 8.

[0163] Furthermore, a unit is constituted by the transistor 11, the resistors 17, 144, 145, 147 and 148, the switch 141, the amplifier 142, the comparator 143 and the inverter 146, so that the unit makes control to supply a predetermined constant current to the electrochemical device conjunctive body 8 in the case where a voltage applied to the electrochemical device conjunctive body 8 is higher than a predetermined voltage, and to supply an electric current larger than the predetermined constant current to the electrochemical device conjunctive body 8 when the voltage applied to the electrochemical device conjunctive body 8 is lower than the predetermined voltage.

[0164] Here, the amplifier 142 obtains a difference between two input signals supplied to its input terminals, and amplifies the difference. The comparator 143 compares the output of the amplifier 142 with a reference voltage VRef. When the output value of the amplifier 142 is not lower than the reference voltage VRef, an output signal of the comparator 143 becomes an L (low) level to thereby bring the switch 141 into the closed state. On the other hand, when the output value of the amplifier 142 is lower than the reference voltage VRef, the output signal of the comparator 143 becomes an H (high) level to thereby bring the switch 141 into the opened state. Incidentally, the reference voltage VRef is a voltage corresponding to a predetermined load voltage on the electrochemical device conjunctive body 8.

[0165] Next, description will be made on the operation. In FIG. 12, when the electrochemical device conjunctive body 8 is operated intermittently to restart the operation of gas conversion in the high humidity environment, the load voltage on the electrochemical device conjunctive body 8 becomes lower than the reference voltage VRef, for example, 2.5 V. Thus, the output of the comparator 143 becomes the H (high) level, and the switch 141 is brought into the opened state. Accordingly, a base current 15 obtained by dividing the DC power supply 6 substantially by the sum of the resistance value of the resistor 17 and the resistance value of the resistor 144 flows into the base 13 of the transistor 11. At this time, the resistance values of the resistors 17 and 144 are set so that a constant current flowing into the electrochemical device conjunctive body 8 will be, for example, 75 mA/cm2.

[0166] After that, when the load voltage on the electrochemical device conjunctive body 8 increases to exceed 2.5 V, the output signal of the comparator 143 becomes the L (low) level so that the switch 141 is brought into the closed state. When the switch 141 is brought into the closed state, a part of the base current 15 is bypassed through the resistor 145 and the switch 141. At this time, setting is done in advance so that a constant current of, for example, 25 mA/cm2 will flow into the electrochemical device conjunctive body 8.

[0167] Incidentally, the inverter 146 and the resistor 148 are provided to prevent the level of the output signal of the comparator 143 from changing again after it changes once. That is, once the output of the comparator 143 becomes the H (high) level, the inverter 146 serves to reduce the minus-side input of the comparator 143 to be lower than 2.5V.

[0168] In such a manner, according to the circuit of FIG. 12, in the intermittent operation in the high humidity environment, significant reduction in the quantity of generated gas at the start of the operation of gas conversion is prevented with precision. In addition, a stable quantity of generated ozone can be obtained during the operation of gas conversion. In addition, in this embodiment, a predetermined constant current (25 mA/cm2) is supplied when the voltage applied to the electrochemical device conjunctive body is not lower than a predetermined voltage. Accordingly, the quantity of generated ozone couldbe kept efficient andmore stablewithout generating excessive gas even if there is a change in the outside air environment such as humidity.

[0169] (Embodiment 9)

[0170] FIG. 13 is a diagram for explaining the configuration of an electrolytic gas converter according to Embodiment 9 of the invention.

[0171] In FIG. 13, the reference numeral 151 represents a switch; and 152, a capacitor. A comparator 143, an inverter 146 and resistors 147 and 148 operate equivalently to those in Embodiment 8 shown in FIG. 12. In addition, when the output signal of the comparator 143 becomes the L (low) level, the switch 151 is brought into the opened state. On the other hand, when the output signal of the comparator 143 becomes the H (high) level, the switch 151 is brought into the closed state. In addition, the capacitance of the capacitor 34 is set so that the value of a current flowing into the electrochemical device conjunctive body 8 will be a predetermined constant current value when the switch 151 is in the opened state.

[0172] In this embodiment, a unit is constituted by the capacitor 152, the switch 151, the comparator 143, the inverter 146, and the resistors 147 and 148, so that the unit makes control to supply an electric current to the electrochemical device conjunctive body 8 in the case where a voltage applied to the electrochemical device conjunctive body 8 is lower than a predetermined voltage, the electric current being larger than that in the case where the voltage is higher than the predetermined voltage.

[0173] In addition, a unit is constituted by the rectifying circuit 32, the capacitors 33 and 34, and the voltage limiting Zener diode 35, so that the unit makes control to supply a predetermined constant current to the electrochemical device conjunctive body 8.

[0174] Furthermore, a unit is constituted by the rectifying circuit 32, the capacitors 33, 34 and 152, the voltage limiting Zener diode 35, the switch 151, the comparator 143, the inverter 146, and the resistors 147 and 148, so that the unit makes control to supply a predetermined constant current to the electrochemical device conjunctive body 8 in the case where a voltage applied to the electrochemical device conjunctive body 8 is not lower than a predetermined voltage, and to supply an electric current larger than the predetermined constant current to the electrochemical device conjunctive body 8 in the case where the voltage applied to the electrochemical device conjunctive body 8 is lower than the predetermined voltage.

[0175] Next, description will be made on the operation. In the circuit of FIG. 13, when the electrochemical device conjunctive body 8 is operated intermittently to restart the operation of gas conversion, the load voltage on the electrochemical device conjunctive body 8 becomes lower than the reference voltage VRef, for example, 2.5 V. Thus, the output of the comparator 143 becomes the H (high) level, and the switch 151 is brought into the closed state. Accordingly, a constant current determined by the parallel capacitance values of the capacitors 34 and 152 flows into the electrochemical device conjunctive body 8. At this time, the capacitance values of the capacitors 34 and 152 are set so that a current of, for example, 75 mA/cm2 will flow into the electrochemical device conjunctive body 8.

[0176] After that, when the load voltage on the electrochemical device conjunctive body 8 increases to be not lower than 2.5 V, the output signal of the comparator 143 becomes the L (low) level so that the switch 151 is brought into the opened state. At this time, setting is done so that a constant current determined only by the capacitor 34, for example, 25 mA/cm2 will flow into the electrochemical device conjunctive body 8.

[0177] In such a manner, according to the circuit of FIG. 13, in the intermittent operation in the high humidity environment, significant reduction in the quantity of generated gas at the start of the operation of gas conversion is prevented with precision. In addition, a stable quantity of generated ozone can be obtained. In addition, in this embodiment, a predetermined constant current (25 mA/cm2) is supplied when the voltage applied to the electrochemical device conjunctive body is not lower than a predetermined voltage. Accordingly, the quantity of generated ozone could be kept efficient and more stable without generating excessive gas even if there is a change in the outside air environment such as humidity.

[0178] (Embodiment 10)

[0179] FIG. 14 is a diagram for explaining the configuration of an electrolytic gas converter according to Embodiment 10 of the invention.

[0180] In FIG. 14, the reference numeral 18 represents a resistor having a resistance value R1; and 19, a constant voltage diode which allows an electric current to be conducted when the voltage is not lower than a specified voltage, that is, an operating voltage (Vz). In addition, a portion C is a constant current circuit constituted by a DC power supply 6, a transistor 11 and a resistor 17.

[0181] In this embodiment, a unit is constituted by the resistor 18 and the constant voltage diode 19 (a portion D), so that the unit makes control to supply an electric current to the electrochemical device conjunctive body 8 in the case where a voltage applied to the electrochemical device conjunctive body 8 is lower than a predetermined voltage, the electric current being larger than that in the case where the voltage is higher than the predetermined voltage.

[0182] In addition, a unit is constituted by the transistor 11 and the resistor 17 so that the unit makes control to supply a predetermined constant current to the electrochemical device conjunctive body 8.

[0183] Furthermore, a unit is constituted by the transistor 11, the resistors 17 and 18, and the constant voltage diode 19, so that the unit makes control to supply a predetermined constant current to the electrochemical device conjunctive body 8 in the case where a voltage applied to the electrochemical device conjunctive body 8 is not lower than a predetermined voltage, and to supply an electric current larger than the predetermined constant current to the electrochemical device conjunctive body 8 in the case where the voltage applied to the electrochemical device conjunctive body 8 is lower than the predetermined voltage.

[0184] Next, description will be made on the operation. In the circuit of FIG. 14, when a load voltage Vd on the electrochemical device conjunctive body 8 is lower than a specified voltage at the start of the operation of gas conversion, the constant voltage diode 19 is brought into the closed state. Thus, a current flows through the electrochemical device conjunctive body 8 and the resistor 18 to the constant voltage diode 19 in this order. At this time, a current having the following current value flows into the electrochemical device conjunctive body 8. That is, the load voltage (Vd) on the electrochemical device conjunctive body 8 and the voltage (Vz) of the constant voltage diode 19 are subtracted from the voltage (V0) of the power supply 6. The voltage obtained thus is divided by the resistance value (R1) of the resistor 18. The current value obtained thus is added to the value of the constant current generated by the constant current circuit in the portion C. Thus, the value of the current flowing into the electrochemical device conjunctive body 8 is obtained. Accordingly, by setting the resistance value (R1) of the resistor 18 properly, as shown in FIG. 15, a current larger than the predetermined constant current generated by the constant current circuit in the portion C can be supplied to the electrochemical device conjunctive body 8 when the load voltage (Vd) on the electrochemical device conjunctive body 8 becomes lower than a predetermined voltage.

[0185] After that, when the load voltage (Vd) on the electrochemical device conjunctive body 8 increases to be not lower than the specified voltage, the constant voltage diode 19 is brought into the opened state. Thus, only the constant current circuit in the portion C operates. At this time, a current 15 has a value obtained by dividing the DC output voltage (VO) of the DC power supply 6 chiefly by the resistance value of the resistor 17. The thus obtained current 15 flows between the emitter 12 and the base 13 of the transistor 11 in the same manner as in the case of Related Art Technique 1. Thus, a predetermined constant current flows into the electrochemical device conjunctive body 8.

[0186] In such a manner, according to the circuit of FIG. 14, when the load voltage on the electrochemical device conjunctive body 8 is lower than a predetermined voltage, a current larger than a predetermined constant current can be supplied to the electrochemical device conjunctive body 8 as shown in FIG. 15. As a result, the load voltage on the electrochemical device conjunctive body 8 can be enhanced so that significant reduction in the quantity of generated gas at the start of the operation of gas conversion is prevented. In addition, a predetermined constant current can be supplied to the electrochemical device conjunctive body 8 when the load voltage on the electrochemical device conjunctive body 8 is not lower than the predetermined voltage. Accordingly, the quantity of generated ozone can be obtained efficiently and stably.

[0187] Next, description will be made on the operation of this embodiment along a specific example while comparison is made with the circuit shown in FIG. 2 which does not have the portion D. Incidentally, the conditions of the intermittent operation and the conditions of the outside air environment are similar to those in Embodiment 1 or 2. In the circuit of FIG. 14, the DC output voltage (V0) of the DC power supply 6 is set to 5 V, the operating voltage (Vz) of the constant voltage diode 19 is set to 2.5 V, and the resistance value of the resistor 18 is set to 5 &OHgr;.

[0188] In this case, when the load voltage on the electrochemical device conjunctive body 8 is lower than the operating voltage (Vz) of the constant voltage diode 19, for example, 2 V, a current of 75 mA/cm2 flowed into the electrochemical device conjunctive body 8. Even at the start of the operation of gas conversion, the voltage of the electrochemical device conjunctive body 8 exceeded 2 V, so that the quantity of generated ozone is prevented from being lowered significantly.

[0189] After that, when the load voltage on the electrochemical device conjunctive body 8 increased to be not lower than 2.5 V, the constant voltage diode 19 is brought into the opened state. Thus, only the constant current circuit in the portion C operated so that a constant current of 25 mA/cm2 flowed into the electrochemical device conjunctive body 8. Accordingly, a stable quantity of generated ozone is obtained.

[0190] In such a manner, according to the circuit of FIG. 14, in the intermittent operation in the high humidity environment, when the load voltage on the electrochemical device conjunctive body 8 is lower than a predetermined voltage, a current larger than a predetermined constant current can be supplied to the electrochemical device conjunctive body 8. As a result, the load voltage on the electrochemical device conjunctive body 8 can be enhanced so that significant reduction in the quantity of generated gas at the start of the operation of gas conversion is prevented. In addition, after that, a predetermined constant current smaller than that at the start of the operation of gas conversion can be supplied to the electrochemical device conjunctive body 8. Accordingly, a stable quantity of generated ozone can be obtained during the operation of gas conversion. In addition, in this embodiment, a predetermined constant current (25 mA/cm2) is supplied to the electrochemical device conjunctive body when the voltage applied to the electrochemical device conjunctive body is not lower than a predetermined voltage. Accordingly, the quantity of generated ozone can be kept efficient and more stable without generating excessive gas even if there is a change in the outside air environment such as humidity.

[0191] Incidentally, although an example using the constant voltage diode 19 is shown in FIG. 14, a Zener diode making conduction with a constant voltage similar to that in the diode 19 may be used. Also in this case, similar effects can be obtained.

[0192] (Embodiment 11)

[0193] FIG. 16 is a diagram for explaining the configuration of an electrolytic gas converter according to Embodiment 11 of the invention.

[0194] In FIG. 16, the reference numerals 50 and 51 represent resistors; 52, a constant voltage diode which makes conduction with a voltage not lower than a specified operating voltage (Vz); 53, a transistor; and 54, a diode. In addition, a portion E is a constant current circuit, which is the same as the circuit shown in FIG. 5.

[0195] In this embodiment, a unit is constituted by the resistors 50 and 51, the constant voltage diode 52, the transistor 53 and the diode 54, so that the unit makes control to supply an electric current to the electrochemical device conjunctive body 8 in the case where a voltage applied to the electrochemical device conjunctive body 8 is lower than a predetermined voltage, the electric current being larger than that in the case where the voltage is higher than the predetermined voltage.

[0196] In addition, a unit is constituted by the rectifying circuit 32, the capacitors 33 and 34, and the voltage limiting Zener diode 35, so that the unit makes control to supply a predetermined constant current to the electrochemical device conjunctive body 8.

[0197] Furthermore, a unit is constituted by the rectifying circuit 32, the capacitors 33 and 34, the voltage limiting Zener diode 35, the resistors 50 and 51, the constant voltage diode 52, the transistor 53 and the diode 54, so that the unit makes control to supply a predetermined constant current to the electrochemical device conjunctive body 8 in the case where a voltage applied to the electrochemical device conjunctive body 8 is not lower than a predetermined voltage, and to supply an electric current larger than the predetermined constant current to the electrochemical device conjunctive body 8 in the case where the voltage applied to the electrochemical device conjunctive body 8 is lower than the predetermined voltage.

[0198] Next, description will be made on the operation. In the circuit of FIG. 16, when the operating voltage (Vz) of the constant voltage diode 52 is, for example, set to 2.5 V, the load voltage on the electrochemical device conjunctive body 8 is lower than 2.5 V at the start of the operation of gas conversion. Accordingly, the constant voltage diode 52 is brought into the opened state. Thus, a current outputted from the circuit E through the resistor 50 is supplied to the electrochemical device conjunctive body 8 through the diode 54 in addition to a current through the transistor 53. Accordingly, as shown in FIG. 17, as the load voltage on the electrochemical device conjunctive body 8 is lower, the current flowing into the electrochemical device conjunctive body 8 increases.

[0199] After that, when the load voltage on the electrochemical device conjunctive body 8 increases to be not lower than 2.5 V, the constant voltage diode 52 is brought into the closed state. Thus, only the current through the transistor 53 flows into the electrochemical device conjunctive body 8 so that the load voltage on the electrochemical device conjunctive body 8 becomes substantially constant. At the same time, the value of the current flowing into the electrochemical device conjunctive body 8 also becomes substantially constant so that a stable quantity of generated ozone can be obtained.

[0200] In such a manner, according to the circuit of FIG. 16, when the load voltage on the electrochemical device conjunctive body 8 is lower than a predetermined voltage, a current larger than a predetermined constant current can be supplied to the electrochemical device conjunctive body 8 as shown in FIG. 17. As a result, the load voltage on the electrochemical device conjunctive body 8 can be enhanced so that significant reduction in the quantity of generated gas at the start of the operation of gas conversion is prevented. In addition, a predetermined constant current can be supplied to the electrochemical device conjunctive body 8 when the load voltage on the electrochemical device conjunctive body 8 is not lower than the predetermined voltage. Accordingly, a stable quantity of generated ozone can be obtained during the operation of gas conversion. In addition, in this embodiment, a predetermined constant current is supplied to the electrochemical device conjunctive body when the voltage applied to the electrochemical device conjunctive body is not lower than a predetermined voltage. Accordingly, the quantity of generated ozone can be kept efficient and more stable without generating excessive gas even if there is a change in the outside air environment such as humidity.

[0201] (Embodiment 12)

[0202] FIG. 18 is a diagram for explaining the configuration of an electrolytic gas converter according to Embodiment 12 of the invention.

[0203] In FIG. 18, the reference numeral 36 represent a resistor; and 37, a constant voltage diode which makes conduction with a voltage not lower than a specified voltage (Vz). In addition, a portion E is a constant current circuit, which is the same as the circuit shown in FIG. 5. A portion F is a circuit added in accordance with this embodiment.

[0204] In this embodiment, a unit is constituted by the rectifying circuit 32, the capacitors 33 and 34, the voltage limiting Zener diode 35, the resistor 36, and the constant voltage diode 37, so that the unit makes control to supply an electric current to the electrochemical device conjunctive body 8 in the case where a voltage applied to the electrochemical device conjunctive body 8 is lower than a predetermined voltage, the electric current being larger than that in the case where the voltage is higher than the predetermined voltage.

[0205] Next, description will be made on the operation. In the circuit of FIG. 18, when the load voltage (Vd) on the electrochemical device conjunctive body 8 is lower than the specified voltage, the constant voltage diode 37 is brought into the opened state. Thus, a constant current determined by the capacitor 34 flows into the electrochemical device conjunctive body 8. After that, when the load voltage on the electrochemical device conjunctive body 8 increases to be not lower than the specified voltage, the constant voltage diode 37 is brought into the closed state. Thus, the current is split to flow through the resistor 36 and the constant voltage diode 37 in this order. Accordingly, the current flowing into the electrochemical device conjunctive body 8 decreases gradually with a predetermined voltage, that is, the operating voltage (Vz) of the constant voltage diode 37 as a border, as shown in FIG. 19. At this time, the split current value decreases in proportion (the inclination is determined by the resistance value of the resistor 36) to the increase of the load voltage on the electrochemical device conjunctive body 8.

[0206] In such a manner, according to the circuit of FIG. 18, when the load voltage on the electrochemical device conjunctive body 8 is lower than a specified voltage, a large current can be supplied to the electrochemical device conjunctive body 8. On the other hand, when the load voltage on the electrochemical device conjunctive body 8 is higher than the specified voltage, a current smaller than the current when the load voltage on the electrochemical device conjunctive body 8 is lower than the specified voltage can be supplied to the electrochemical device conjunctive body 8. As a result, in the intermittent operation in the high humidity environment, significant reduction in the quantity of converted gas at the start of the operation of gas conversion is prevented with precision. In addition, a stable quantity of converted gas can be obtained during the operation of gas conversion.

[0207] Next, description will be made on the operation of this embodiment along a specific example while comparison is made with Related Art Technique 2. Incidentally, the conditions of the intermittent operation and the conditions of the outside air environment are similar to those in Embodiment 1 or 2. In the circuit of FIG. 18, for example, assuming that the operating voltage (Vz) of the constant voltage diode 37 is 2.5 V, the AC input is 100 V at 60 cycles, the voltage applied to the electrochemical device conjunctive body 8 by the voltage limiting Zener diode 35 is 5 V, the value of a constant current determined by the capacitor 34 is 75 mA/cm21 and the resistance value of the resistor 36 is 20 &OHgr;, the load voltage on the electrochemical device conjunctive body 8 is lower than 2.5 V at the start of the operation of gas conversion. Thus, a constant current of 75 mA/cm2 flows into the electrochemical device conjunctive body 8. As a result, a voltage exceeding 2V is applied to the electrochemical device conjunctive body 8 even at the start of the operation of gas conversion, so that the quantity of generated ozone is prevented from being lowered significantly.

[0208] After that, when the load voltage on the electrochemical device conjunctive body 8 increased to be not lower than 2.5 V, the current flowing into the electrochemical device conjunctive body 8 decreased so that the load voltage on the electrochemical device conjunctive body 8 became substantially constant. At the same time, the value of the current flowing into the electrochemical device conjunctive body 8 also became substantially constant. Accordingly, a stable quantity of generated ozone is obtained.

[0209] In such a manner, according to the circuit of FIG. 18, a large current can be supplied to the electrochemical device conjunctive body 8 when the operation of gas conversion is restarted. Thus, in the intermittent operation in the high humidity environment, significant reduction in the quantity of generated ozone at the restart of the operation of gas conversion is prevented with precision. In addition, after that, a small current can be supplied the electrochemical device conjunctive body 8 so that a stable quantity of generated ozone can be obtained.

[0210] Incidentally, although examples using the constant voltage diodes 137 and 52 are shown in Embodiments 11 and 12 shown in FIGS. 16 and 18 respectively, a Zener diode making conduction with a constant voltage similar to that in each of these constant voltage diodes may be used. Also in this case, similar effects can be obtained.

[0211] In addition, description in the respective Embodiments 5, 7 and 10 to 12 is made on the case where the operating voltage (Vz) of the constant voltage diode 127, 137, 19, 37, 52 is set to 2.5 V. The operating voltage (Vz) is not limited to this value, but may be set properly to make the load voltage on the electrochemical device conjunctive body 8 higher than 3 V.

[0212] In addition, description in the respective Embodiments 1 to 12 is made on the case where the voltage (VO) of the DC power supply 6 or the output voltage determined by the Zener diode 35 is set to 5 V. The voltage (VO) of the DC power supply 6 or the output voltage determined by the Zener diode 35 is not limited to this value, but may be combined properly with the operating voltage (Vz) of the constant voltage diode 127, 137, 19, 37, 52 so as to make the load voltage on the electrochemical device conjunctive body 8 higher than 3 V.

[0213] In addition, description in the respective Embodiments 1 to 10 is made on the case where a current flowing into the electrochemical device conjunctive body 8 in the steady condition or a current flowing into the electrochemical device conjunctive body 8 when the load voltage on the electrochemical device conjunctive body 8 is larger than a specified voltage is set to 25 mA/cm2. The current is not limited to this value, but may be set to be smaller or larger in accordance with a required quantity of generated ozone. Incidentally, when there is a limit in the capacity of the DC power supply 6, it is desired that the constant current density is as small as possible.

[0214] In addition, in the respective Embodiments 1 to 10 and 12, when the load voltage on the electrochemical device conjunctive body 8 is lower than a specified voltage, the current flowing into the electrochemical device conjunctive body 8 is set to 75 mA/cm2. The current is not limited to this value, but may be set properly to be larger than a constant current flowing in the steady condition. In this case, there is an advantage that a stable quantity of generated gas can be obtained in a short time if the current flowing into the electrochemical device conjunctive body 8 is increased. Thus, a larger current flows into the electrochemical device conjunctive body 8 so that the quantity of generated ozone increases.

[0215] In addition, description in Embodiments 1 to 12 is made on the case where the high humidity environment is 25° C. in temperature and 90% in relative humidity. The invention is not limited to this environment, but similar effects can be obtained in the case where environment has a higher temperature or humidity or in the case where environment has a lower temperature or humidity, on the contrary.

[0216] In addition, in Embodiments 1, 2, 4, 5, 6, 8 and 10, a primary battery such as a plurality of dry cells, a chargeable secondary battery, or a circuit having a function to convert an AC voltage into a DC voltage may be used as the DC power supply 6.

[0217] (Embodiment 13)

[0218] FIG. 20 is a diagram for explaining the configuration of an electrolytic gas converter according to Embodiment 13 of the invention. The invention associated with this embodiment is developed by finding the following fact. Control is made to block the electrochemical device conjunctive body 8 perfectly from a control circuit during the suspension of the operation of gas conversion. That is, control is made to release a circuit connected to the electrochemical device conjunctive body 8. Thus, stable performance can be obtained for a longer time.

[0219] In FIG. 20, the reference numeral 301 represents a relay; and 302, a relay switch. The other configuration is similar to that in FIG. 12 shown in Embodiment 8.

[0220] In this embodiment, a unit is constituted by the relay 301 and the relay switch 302, so that the unit makes control in a manner such that a circuit connected to the electrochemical device conjunctive body 8 is released during the suspension of the operation of gas conversion.

[0221] Next, description will be made on the operation. In the circuit of FIG. 20, at the start of the operation of gas conversion, the relay 301 operates as soon as the power supply 6 operates. Thus, the relay switch 302 is brought into the closed state (wire connection is connected) so that the circuit of FIG. 20 operates. After that, when the operation of the circuit of FIG. 20 is suspended, the relay 301 is suspended so that the relay switch 302 is brought into the opened state (wire connection is disconnected). Thus, by providing the relay 301 in the circuit, the electrochemical device conjunctive body 8 can be blocked perfectly from the circuit when the circuit of FIG. 20 is in suspension. That is, the circuit connected to the electrochemical device conjunctive body 8 is released during the suspension of the operation of gas conversion. Thus, stable performance could be obtained for a longer time.

[0222] Incidentally, description is made above on the case where the relay 301 and the relay switch 302 are provided in the electrolytic gas converter according to Embodiment 8 shown in FIG. 12 for making control so that the circuit connected to the electrochemical device conjunctive body 8 is released during the suspension of the operation of gas conversion. The invention is not limited to this case, but may be applied to another circuit having a circuit for controlling a voltage applied to the electrochemical device conjunctive body 8 or a current flowing into the electrochemical device conjunctive body 8. For example, in an electrolytic gas converter according to any one of Embodiments 1 to 4, or in an electrolytic gas converter according to any one of Embodiments 9 to 12, the relay 301 and the relay switch 302 may be provided to make control so that the circuit connected to the electrochemical device conjunctive body 8 is released during the suspension of the operation of gas conversion. In this case, similar effects can be obtained.

[0223] In addition, in a related-art electrolytic gas converter shown in FIG. 21 or an electrolytic gas converter shown in FIG. 2 or 6, the relay 301 and the relay switch 302 may be provided to make control so that the circuit connected to the electrochemical device conjunctive body 8 is released during the suspension of the operation of gas conversion. In this case, similar effects can be obtained.

[0224] Further, also in an electrolytic gas converter described in Embodiments 5 to 7 and having a unit for making control so that a voltage low enough or a current small enough not to convert moisture into gas is applied or conducted to the electrochemical device conjunctive body 8 during the suspension of the operation of gas conversion, there may be provided such a design that control is made so that the circuit connected to the electrochemical device conjunctive body 8 is released, for example, when the intermittent operation is stopped seasonally.

[0225] (Embodiment 14)

[0226] For example, when the electrochemical device conjunctive body 8 is installed as an ozone generating device in electric equipment such as an air conditioner, a refrigerator or a dish washer, a circuit according to the invention shown in FIG. 1, FIG. 3, FIG. 4 to FIG. 14, FIG. 16 or FIG. 18, is used. Then, the circuit allows a predetermined current to be supplied to the electrochemical device conjunctive body 8 so that the ozone concentration in such electric equipment becomes desired one. Thus, even in the intermittent operation in the high humidity environment, the quantity of generated gas can be prevented from being lowered significantly at the start of the operation of gas conversion, while a stable quantity of generated ozone can be obtained during the operation of gas conversion. Accordingly, predetermined ozone concentration can be obtained. In addition, the invention is not limited to such electric equipment. Also when the electrochemical device conjunctive body 8 is installed in a car, a cleaner, a food container or a refuse container, effects similar to those in the case can be obtained.

[0227] In addition, also when the electrochemical device conjunctive body 8 is used as a dehumidifying device, an oxygen generating device, or a hydrogen generating device, a circuit according to the invention shown in FIG. 1, FIG. 3, FIG. 4 to FIG. 14, FIG. 16 or FIG. 18, is used to supply a predetermined current to the electrochemical device conjunctive body 8. In this case, even in the intermittent operation in the high humidity environment, a stable quantity of converted gas can be obtained.

[0228] Incidentally, when the electrochemical device conjunctive body 8 is used as an ozone generating device, that is, when the electrolytic gas converter is an ozone generator, for example, an anode in which &bgr;-type or &agr;-type lead dioxide is thinly electrodeposited on an expanded metal substrate made of titanium and plated with platinum as undercoat is used as the anode 1 of the electrochemical device conjunctive body 8. As the cathode 2, for example, there is used a cathode in which a solid polymer electrolyte obtained by liquefying carbon powder carrying platinum fine particles is fixedly attached as binder onto a porous carbon fiber substrate.

[0229] In addition, when the electrochemical device conjunctive body 8 is used as an oxygen gas generating device or a dehumidifying device, that is, when the electrolytic gas converter is an oxygen gas generator or a dehumidifier, for example, a porous expanded metal substrate made of titanium and plated with platinum is used as the anode 1 of the electrochemical device conjunctive body 8. In this case, oxygen is generated from the anode while water is released from the back of the cathode.

[0230] In addition, when the electrochemical device conjunctive body 8 is used as a hydrogen generating device, that is, when the electrolytic gas converter is a hydrogen gas generator, for example, a porous expanded metal substrate made of titanium and plated with platinum is used as each of the anode 1 and the cathode 2. In this case, hydrogen gas is generated in the cathode.

[0231] As described above, according to the invention, there is provided a first electrolytic gas converter including: an electrochemical device conjunctive body having an anode and a cathode each having a catalyst layer provided on a substrate made of a conductive porous base material, and a solid polymer electrolyte membrane disposed between the anode and the cathode, a DC voltage being applied to the electrochemical device conjunctive body so as to convert atmospheric moisture into ozone gas, oxygen gas or hydrogen gas; and a unit for making control so that an electric current flows into the electrochemical device conjunctive body during a predetermined period of time after start of operation of gas conversion, the electric current being larger than that after the predetermined period of time passes. Accordingly, in the intermittent operation in the high humidity environment, the quantity of converted gas is prevented from being lowered significantly at the start of the operation of gas conversion, while a stable quantity of converted gas can be obtained during the operation of gas conversion.

[0232] Further, according to the invention, there is provided a second electrolytic gas converter in which in the first electrolytic gas converter, a unit is provided for making control so that an electric current is made to flow into the electrochemical device conjunctive body periodically during a predetermined period of time after start of operation of gas conversion, the electric current being larger than that after the predetermined period of time passes. Accordingly, in the intermittent operation in the high humidity environment, the quantity of converted gas is prevented from being lowered significantly at the start of the operation of gas conversion, while a stable quantity of converted gas can be obtained during the operation of gas conversion.

[0233] Further, according to the invention, there is provided a third electrolytic gas converter in which in the first electrolytic gas converter, a unit is provided for making control so that a predetermined constant electric current flows into the electrochemical device conjunctive body after the predetermined period of time passes since the start of operation of gas conversion. Accordingly, the quantity of converted gas can be obtained efficiently and stably without generating excessive gas even if there is a change in the environmental conditions. Thus, the stability of the quantity of converted gas is more improved.

[0234] Further, according to the invention, there is provided a fourth electrolytic gas converter including: an electrochemical device conjunctive body having an anode and a cathode each having a catalyst layer provided on a substrate made of a conductive porous base material, and a solid polymer electrolyte membrane disposed between the anode and the cathode, a DC voltage being applied to the electrochemical device conjunctive body so as to convert atmospheric moisture into ozone gas, oxygen gas or hydrogen gas; and a unit for making control so that a voltage low enough or an electric current small enough not to convert the moisture into the gas is applied or conducted to the electrochemical device conjunctive body during suspension of operation of gas conversion. Accordingly, in the intermittent operation in the high humidity environment, the quantity of converted gas is prevented from being lowered significantly at the start of the operation of gas conversion, while a stable quantity of converted gas can be obtained during the operation of gas conversion.

[0235] Further, according to the invention, there is provided a fifth electrolytic gas converter in which in the fourth electrolytic gas converter, a unit is provided for making control so that a predetermined constant electric current flows into the electrochemical device conjunctive body during the operation of gas conversion. Accordingly, the quantity of converted gas can be obtained efficiently and stably without generating excessive gas even if there is a change in the environmental conditions. Thus, the stability of the quantity of converted gas is more improved.

[0236] Further, according to the invention, there is provided a sixth electrolytic gas converter including: an electrochemical device conjunctive body having an anode and a cathode each having a catalyst layer provided on a substrate made of a conductive porous base material, and a solid polymer electrolyte membrane disposed between the anode and the cathode, a DC voltage being applied to the electrochemical device conjunctive body so as to convert atmospheric moisture into ozone gas, oxygen gas or hydrogen gas; and a unit for making control so that an electric current is made to flow into the electrochemical device conjunctive body in a case where a voltage applied to the electrochemical device conjunctive body is lower than a predetermined voltage, the electric current being larger than in another case where the voltage is higher than the predetermined voltage. Accordingly, in the intermittent operation in the high humidity environment, the quantity of converted gas is prevented from being lowered significantly at the start of the operation of gas conversion, while a stable quantity of converted gas can be obtained during the operation of gas conversion.

[0237] Further, according to the invention, there is provided a seventh electrolytic gas converter in which in the sixth electrolytic gas converter, a unit is provided for making control so that a predetermined constant electric current is made to flow into the electrochemical device conjunctive body when a voltage applied to the electrochemical device conjunctive body is not lower than a predetermined voltage. Accordingly, the quantity of converted gas can be obtained efficiently and stably without generating excessive gas even if there is a change in the environmental conditions. Thus, the stability of the quantity of converted gas is more improved.

[0238] Further, according to the invention, there is provided an eighth electrolytic gas converter in which in the first or sixth electrolytic gas converter, a unit is provided for making control so that a circuit connected to the electrochemical device conjunctive body is released during suspension of operation of gas conversion. Accordingly, a stable performance can be obtained for a longer time.

[0239] Further, according to the invention, there is provided a ninth electrolytic gas converter in which in the any one of the first through eighth electrolytic gas converters, the electrochemical device conjunctive body is used as an ozone generating device, an oxygen generating device, a hydrogen generating device, or a dehumidifying device. Accordingly, in the intermittent operation in the high humidity environment, the quantity of generated ozone, oxygen and hydrogen gas or the humidified quantity is prevented from being lowered significantly at the start of the operation of gas conversion, while a stable quantity of generated ozone, oxygen and hydrogen gas or a stable humidified quantity can be obtained during the operation of gas conversion.

[0240] Further, according to the invention, there is provided first electric equipment having any one of the first through eighth electrolytic gas converters. Accordingly, in the intermittent operation in the high humidity environment, the quantity of converted gas is prevented from being lowered significantly at the start of the operation of gas conversion, while a stable quantity of converted gas can be obtained during the operation.

Claims

1. An electrolytic gas converter comprising:

an electrochemical device conjunctive body having an anode and a cathode each having a catalyst layer provided on a substrate made of a conductive porous base material, and a solid polymer electrolyte membrane disposed between said anode and said cathode, a DC voltage being applied to said electrochemical device conjunctive body so as to convert atmospheric moisture into ozone gas, oxygen gas or hydrogen gas; and

a unit for controlling so that an electric current flows into said electrochemical device conjunctive body during a predetermined period of time after start of operation of gas conversion, the electric current being larger than that after the predetermined period of time passes.

2. The electrolytic gas converter according to claim 1, further comprising:

a unit for controlling so that an electric current flows into said electrochemical device conjunctive body periodically during a predetermined period of time after start of operation of gas conversion, the electric current being larger than that after the predetermined period of time passes.

3. The electrolytic gas converter according to claim 1, further comprising:

a unit for controlling so that a predetermined constant electric current flows into said electrochemical device conjunctive body after the predetermined period of time passes since the start of operation of gas conversion.

4. An electrolytic gas converter comprising:

an electrochemical device conjunctive body having an anode and a cathode each having a catalyst layer provided on a substrate made of a conductive porous base material, and a solid polymer electrolyte membrane disposed between said anode and said cathode, a DC voltage being applied to said electrochemical device conjunctive body so as to convert atmospheric moisture into ozone gas, oxygen gas or hydrogen gas; and

a unit for controlling so that a voltage low enough or an electric current small enough not to convert the moisture into the gas is applied or conducted to said electrochemical device conjunctive body during suspension of operation of gas conversion.

5. The electrolytic gas converter according to claim 4, further comprising:

a unit for controlling so that a predetermined constant electric current flows into said electrochemical device conjunctive body during the operation of gas conversion.

6. An electrolytic gas converter comprising:

an electrochemical device conjunctive body having an anode and a cathode each having a catalyst layer provided on a substrate made of a conductive porous base material, and a solid polymer electrolyte membrane disposed between said anode and said cathode, a DC voltage being applied to said electrochemical device conjunctive body so as to convert atmospheric moisture into ozone gas, oxygen gas or hydrogen gas; and

a unit for controlling so that an electric current flows into said electrochemical device conjunctive body in a case where a voltage applied to said electrochemical device conjunctive body is lower than a predetermined voltage, the electric current being larger than in another case where the voltage is higher than the predetermined voltage.

7. The electrolytic gas converter according to claim 6, further comprising:

a unit for controlling so that a predetermined constant electric current flows into said electrochemical device conjunctive body when a voltage applied to said electrochemical device conjunctive body is not lower than a predetermined voltage.

8. The electrolytic gas converter according to claim 1, further comprising:

a unit for controlling so that a circuit connected to said electrochemical device conjunctive body is released during suspension of operation of gas conversion.

9. The electrolytic gas converter according to claim 1, wherein said electrochemical device conjunctive body is used as an ozone generating device, an oxygen generating device, a hydrogen generating device, or a dehumidifying device.

10. Electric equipment comprising an electrolytic gas converter according to claim 1.

11. The electrolytic gas converter according to claim 4, further comprising:

a unit for controlling so that a circuit connected to said electrochemical device conjunctive body is released during suspension of operation of gas conversion.

12. The electrolytic gas converter according to claim 4, wherein

said electrochemical device conjunctive body is used as an ozone generating device, an oxygen generating device, a hydrogen generating device, or a dehumidifying device.

13. Electric equipment comprising an electrolytic gas converter according to claim 4.

14. The electrolytic gas converter according to claim 6, further comprising:

a unit for controlling so that a circuit connected to said electrochemical device conjunctive body is released during suspension of operation of gas conversion.

15. The electrolytic gas converter according to claim 6, wherein

said electrochemical device conjunctive body is used as an ozone generating device, an oxygen generating device, a hydrogen generating device, or a dehumidifying device.

16. Electric equipment comprising an electrolytic gas converter according to claim 8.