JP7209061B1 - ozone generator - Google Patents

Abstract

An object of the present invention is to determine an abnormality in which an actual ozone concentration deviates from a target concentration during feedback control. An ozone generator (1) includes an ozone supply section (5), a detection section (10), a control section (12), and an abnormality determination section (14). The ozone supply unit 5 supplies ozone to the external space 90 . The detector 10 detects the ozone concentration by an electrochemical method. The control unit 12 performs first control for feedback-controlling the ozone supply unit 5 so that the ozone concentration detected by the detection unit 10 approaches the target concentration, and performs first control when a determination condition is satisfied during execution of the first control. and a second control that stops the control. The abnormality determination unit 14 determines an abnormality based on the degree of change in the ozone concentration detected by the detection unit 10 from when the determination condition is met until a predetermined period of time elapses. [Selection drawing] Fig. 1

Description

The present invention relates to ozone generators.

Patent Literature 1 discloses an example of an ozone generator. This ozone generator performs feedback control based on a signal from an external ozone sensor so that the external ozone concentration in the external space of the ozone generator becomes a target external ozone concentration.
Further, Patent Document 2 discloses an example of an ozone sensor. This ozone sensor is an electrochemical sensor using the diaphragm polarography method, and quantifies ozone gas from the magnitude of the current flowing between the working electrode and the counter electrode.

JP 2019-099398 A JP 2020-16593 A

In the electrochemical gas sensor exemplified in Patent Document 2, not only ozone gas but also gases other than ozone gas may affect the magnitude of current flowing between the working electrode and the counter electrode. As a result, the ozone concentration measured by the sensor may deviate from the actual external ozone concentration. Therefore, when feedback control is performed as exemplified in Patent Document 1 using an electrochemical gas sensor exemplified in Patent Document 2, the actual external ozone concentration may deviate from the target external ozone concentration.

SUMMARY OF THE INVENTION An object of the present invention is to provide a technique capable of determining an abnormality in which the actual ozone concentration deviates from the target concentration during feedback control.

[1] An ozone generator of the present invention includes an ozone supply section, a detection section, a control section, and an abnormality determination section. The ozone supply unit supplies ozone to the external space. The detector detects the ozone concentration by an electrochemical method. The control unit performs first control for feedback-controlling the ozone supply unit so that the ozone concentration detected by the detection unit approaches the target concentration, and stops the first control when a determination condition is satisfied during execution of the first control. and a second control that causes the The abnormality determination unit determines an abnormality based on the degree of change in the ozone concentration detected by the detection unit from when a determination condition is established until a predetermined period elapses.

In this ozonizer, when the first control is stopped, the degree of change in the ozone concentration (detected concentration) detected by the detection unit differs depending on the actual ozone concentration. Therefore, the ozone generator can determine an abnormality in which the actual ozone concentration during feedback control deviates from the target concentration based on the degree of change.

[2] In the second control, the control section may control the ozone supply section to supply low-concentration ozone or stop the ozone supply section. The abnormality determination unit may determine the abnormality based on the degree of decrease in the ozone concentration detected by the detection unit after the determination condition is satisfied until the predetermined period elapses.

According to this configuration, it is possible to determine an abnormality while suppressing an increase in the ozone concentration in the external space.

[3] In the ozonizer of [2], the abnormality determination unit may determine that there is abnormality when determining that the degree of decrease exceeds a threshold value.

According to this configuration, it is possible to determine an abnormality in which the actual ozone concentration during feedback control is higher than the target concentration.

[4] In the ozone generator of [3], the control unit executes the first control when determining that the degree of decrease does not exceed the threshold, and the degree of decrease exceeds the threshold. feedback control of the ozone supply unit so that the concentration detected by the detection unit approaches a second target concentration lower than the target concentration, or causes the ozone supply unit to supply low-concentration ozone. Alternatively, third control may be executed to bring the ozone supply unit into a stopped state.

According to this configuration, when it is determined that the degree of decrease does not exceed the threshold, the first control is resumed, and when it is determined that the degree of decrease exceeds the threshold, the supply of ozone is reduced or stopped. can be made

[5] In the ozone generator of [4], when the control unit causes the ozone supply unit to supply low-concentration ozone in the third control, the larger the degree of decrease, the smaller the amount of supplied ozone. You may control the said ozone supply part so that it may become.

According to this configuration, the ozone supply amount can be reduced as the actual ozone concentration is estimated to be higher.

[6] The ozone generator may include a humidifying section that humidifies the external space.

According to this configuration, the ozone generator can also function as a humidifier.

According to the present invention, it is possible to determine an abnormality in which the actual ozone concentration during feedback control deviates from the target concentration.

FIG. 1 is a block diagram schematically showing the ozone generator of the first embodiment. FIG. 2 is a graph showing changes over time in ozone concentration after stopping the first control. FIG. 3 is a flow chart showing the process flow performed by the ozone generator.

1. First Embodiment 1-1. Configuration of Ozone Generator The ozone generator 1 shown in FIG. 1 is a device that generates ozone and supplies the ozone to an external space 90 outside itself. The ozone generator 1 includes a case 3, an ozone supply unit 5, a humidification unit 7, a detection unit 10, a control unit 12, an abnormality determination unit 14, an operation unit 16, and a display unit 18. there is

The case 3 accommodates an ozone supply unit 5 , a humidification unit 7 , a detection unit 10 , a control unit 12 , an abnormality determination unit 14 , an operation unit 16 , and a display unit 18 . A space outside the case 3 is a space outside the ozone generator 1 and is an external space 90 . The case 3 has an opening 3A. The gas existing in the external space 90 can be introduced into the detection section 10 through the opening 3A.

The ozone supply unit 5 generates ozone and supplies the generated ozone to the external space 90 . The ozone supply unit 5 has an ozone generator 5A, a fan 5B, and a supply pipe 5C. 5 A of ozone generators are apparatuses which generate ozone. A method for generating ozone by the ozone generator 5A is not limited. In this embodiment, the ozone generator 5A has an AC power supply (not shown) such as a transformer and an ozone generator (not shown). An AC power supply converts a DC voltage into an AC voltage. The ozone generator discharges (for example, dielectric barrier discharge) when an AC voltage converted by an AC power source is applied, and generates ozone using oxygen in a target gas (for example, air) introduced from the external space 90 as a raw material. generate. The amount of ozone generated by the ozone generator 5A is adjusted by adjusting the voltage applied to the ozone generator 5A (more specifically, the effective value of the AC voltage applied to the ozone generator). The amount of ozone generated increases as the voltage applied to the ozone generator (more specifically, the effective value of the AC voltage applied to the ozone generator) increases. 5 A of ozone generators send in the ozone which self generated to 5 C of supply pipes.

The supply pipe 5</b>C is a pipe that guides the ozone generated by the ozone generator 5</b>A to the external space 90 . The flow rate and flow velocity of the gas flowing through the supply pipe 5C are adjusted by the fan 5B.

The fan 5B is configured as a blower. The fan 5B includes, for example, a rotating body (not shown) having a plurality of blades, a power section (motor or the like not shown) that rotates the rotating body, and a drive circuit (not shown) that adjusts the rotation of the power section. and The drive circuit controls the number of revolutions of the rotating body to the number of revolutions instructed by the control section 12 . As the number of revolutions of the rotating body constituting the fan 5B increases, the flow rate and flow velocity of the gas flowing through the supply pipe 5C increase.

The amount of ozone supplied to the external space 90 by the ozone supply unit 5 is adjusted by adjusting at least one of the voltage applied to the ozone generator 5A and the rotation speed of the fan 5B.

The humidifying section 7 supplies water vapor or mist to the external space 90 outside the ozone generator 1 to humidify the external space 90 . The humidifying section 7 has a humidifying device 7A, a fan 7B, and a supply pipe 7C.

The humidifier 7A is a device that generates steam or mist. Various known methods can be adopted for the humidifier 7A to generate water vapor or mist. The humidifier 7A feeds the steam or mist generated by itself into the supply pipe 7C.

The supply pipe 7C is a pipe that guides the water vapor or mist generated by the humidifier 7A to the external space 90 outside the ozone generator 1 . The flow rate and flow velocity of the gas flowing through the supply pipe 7C are adjusted by the fan 7B.

The fan 7B is configured as a blower. The fan 7B includes, for example, a rotating body (not shown) having a plurality of blades, a power section (such as a motor not shown) that rotates the rotating body, and a drive circuit (not shown) that adjusts the rotation of the power section. , and the drive circuit controls the number of rotations of the rotating body to the number of rotations instructed by the control unit 12 . As the number of rotations of the rotating body constituting the fan 7B increases, the flow rate and flow velocity of the gas flowing through the supply pipe 7C increase.

When the humidifying device 7A generates water vapor or mist at a constant generation speed, the flow rate and flow velocity of the water vapor or mist flowing through the supply pipe 7C increase as the rotation speed of the fan 7B increases. Therefore, the controller 12 can adjust the supply speed of steam or mist (the amount of steam or mist supplied to the external space 90 per unit time) by adjusting the rotation speed of the fan 7B.

The detection unit 10 is an ozone sensor that detects ozone concentration by an electrochemical method. "Electrochemical method" is, for example, a constant potential electrolysis method. The detection unit 10 detects the ozone concentration of air introduced from the external space 90 . A signal indicating the ozone concentration (hereinafter also referred to as “detected concentration”) detected by the detection unit 10 is input to the control unit 12 and the abnormality determination unit 14, respectively.

The control unit 12 and the abnormality determination unit 14 are mainly composed of a microcomputer, for example, and have a CPU, a ROM, a RAM, and the like. The control unit 12 controls operations of the ozone supply unit 5 , the humidification unit 7 and the display unit 18 . The operation unit 16 is, for example, a push-type switch. The display unit 18 is, for example, an LED lamp, a liquid crystal display, or the like.

1-2. Operation of Ozone Generator The control unit 12 executes first control for feedback-controlling the ozone supply unit 5 so that the ozone concentration detected by the detection unit 10 approaches the target concentration.

The target density may be a predetermined fixed value, or may be a value set by a setting operation performed using the operation unit 16 . The target concentration is preferably higher from the viewpoint of inactivating viruses floating in the external space 90, but is preferably kept to a level that does not adversely affect the human body, for example, greater than 0 ppb (parts per billion) and 100 ppb. The following are preferable. In this embodiment, the target density is set to 50 ppb.

In the first control, the control unit 12 feedback-controls the ozone supply unit 5 by, for example, adjusting the voltage applied to the ozone generator 5A of the ozone supply unit 5 . In this embodiment, in the first control, the controller 12 keeps the rotational speed of the rotating body constituting the fan 5B constant, but it may be changed.

The control unit 12 executes second control to stop the first control when the determination condition is satisfied during the execution of the first control. Judgment conditions are not particularly limited. The determination condition may be, for example, that a second predetermined period (for example, 120 minutes) has elapsed since the first control was started. The second predetermined period may be a predetermined fixed value, may vary according to the ozone concentration or the like, or may be a value set by a setting operation performed using the operation unit 16. There may be. The second predetermined period may be determined based on the assumed upper limit value of the ozone concentration during execution of the first control. For example, if the upper limit value is assumed to be 160 ppb, the second predetermined period may be less than 200 minutes (for example, 120 minutes) so that the human body will not be affected even if the state of 160 ppb continues. As another example, the determination condition may be that a determination operation has been performed by the operation unit 16 .

The second control includes, for example, control to supply a constant amount of ozone, control to supply ozone with regular changes, control to stop the ozone supply unit 5, and the like. In the second control, the control unit 12 controls the ozone supply unit 5 to supply, for example, low-concentration ozone, or stops the ozone supply unit 5 . That is, in the second control, the control unit 12 controls the ozone supply unit 5 to supply a constant amount of low-concentration ozone, or controls the ozone supply unit 5 to supply low-concentration ozone with regular changes. control the unit 5 or stop the ozone supply unit 5;

"Low concentration" means an amount smaller than the amount of ozone supplied from the ozone supply unit 5 when the determination condition is satisfied during execution of the first control, and is a "predetermined value". or "a value determined based on the detected concentration". In this embodiment, it is assumed that gases other than ozone act on the positive side with respect to the detected concentration. Therefore, the "predetermined value" may be, for example, a value smaller than the ozone supply amount required to maintain the actual concentration at the target concentration in an environment where there is no influence of gases other than ozone. Also, the "value determined based on the detected concentration" may be, for example, 30% or less of the ozone supply amount supplied from the ozone supply unit 5 when the determination condition is satisfied during execution of the first control. The ozone supply amount supplied from the ozone supply unit 5 is correlated with the voltage applied to the ozone supply unit 5 when the rotation speed of the rotating body constituting the fan 5B is constant. It can be compared with the voltage applied to the ozone supply unit 5 when the determination condition is satisfied. In other words, the control unit 12 maintains the rotation speed of the rotating body that constitutes the fan 5B at the rotation speed when the determination condition is satisfied, and changes the voltage applied to the ozone supply unit 5 during execution of the first control. By setting the voltage to be 30% or less of the voltage applied to the ozone supply unit 5 when the determination condition is satisfied, the ozone supply amount supplied from the ozone supply unit 5 can be reduced to 30% or less.

The abnormality determination unit 14 determines abnormality based on the degree of change in the ozone concentration detected by the detection unit 10 from when the determination condition is met until a predetermined period of time elapses. Here, "abnormality" means "abnormality in which the actual ozone concentration during feedback control deviates from the target concentration". The detection unit 10 that detects the ozone concentration by the electrochemical method described above is also affected by gases other than ozone. For example, in the presence of a reducing gas having properties opposite to those of ozone, which is an oxidizing gas, it is assumed that the detection result of the detection unit 10 that detects the ozone concentration by an electrochemical method will be negatively affected. be. In this case, the detected concentration is lower than the actual ozone concentration (hereinafter also referred to as "actual concentration"). Therefore, when the controller 12 performs feedback control so that the detected concentration approaches the target concentration in the first control, the actual concentration becomes higher than the target concentration. The abnormality determination unit 14 can determine an abnormality that occurs in this manner. The predetermined period is a predetermined period, such as 10 minutes.

The abnormality determination unit 14 controls the ozone supply unit 5 to supply low-concentration ozone in the second control or stops the ozone supply unit 5 in the second control. Abnormality is determined on the basis of the degree of decrease after a predetermined period of time has elapsed. When the control unit 12 controls the ozone supply unit 5 to supply low-concentration ozone or stops the ozone supply unit 5 in the second control, the detected concentration decreases during execution of the second control. At this time, the degree of decrease in detected density tends to increase as the actual density increases. Therefore, the abnormality determination unit 14 can determine abnormality based on the degree of decrease in the detected density.

Further, the abnormality determination unit 14 determines that there is an abnormality when determining that the degree of decrease exceeds the threshold. As described above, when reducing gas exists, the actual concentration tends to be higher than the target concentration in the first control. Also, the higher the actual concentration, the greater the degree of decrease when the second control is executed. Therefore, when the second control is executed, when the reducing gas is present, the degree of decrease is lower than when the reducing gas is not present (that is, when the actual concentration matches the target concentration). becomes larger.

The abnormality determination unit 14 determines an abnormality by grasping in advance the degree of decrease after a predetermined period of time when the actual concentration when the determination condition is satisfied is an abnormal value. I can. FIG. 2 shows graphs G1, G2, and G3 based on actual measurements. G1 represents the change over time of the ozone concentration when the second control (here, stopping the ozone supply unit 5) is executed from the state where the actual concentration matches the target concentration (50 ppb). G2 represents the change over time of the ozone concentration when the second control is executed from the state where the actual concentration is 100 ppb. G3 represents the change over time of the ozone concentration when the second control is executed from the state where the actual concentration is 130 ppb. Let C1 be the degree of decrease from when the second control is started in a state where the actual density matches the target density until a predetermined period elapses. Let C2 be the degree of decrease from when the second control is started when the actual concentration is 100 ppb until a predetermined period elapses. Let C3 be the degree of decrease from when the second control is started when the actual concentration is 130 ppb until a predetermined period elapses.

The "threshold" mentioned above is a value larger than C1, and is set to C2 in this embodiment. When the actual concentration exceeds 100 ppb at the time when the determination condition is satisfied, as in G3 of FIG. 2, the degree of decrease exceeds the threshold value C2. For this reason, the abnormality determination unit 14 determines that the degree of decrease exceeds the threshold, and determines that there is an abnormality. Conversely, when the actual concentration does not exceed 100 ppb when the determination condition is satisfied, as in G1 of FIG. 2, the degree of decrease does not exceed the threshold C2. Therefore, the abnormality determination unit 14 determines that the degree of decrease does not exceed the threshold, and does not determine that there is an abnormality.

The control unit 12 executes the first control when it is determined that the degree of decrease does not exceed the threshold, and executes the third control when it is determined that the degree of decrease exceeds the threshold. The third control is feedback control of the ozone supply unit 5 so that the detected concentration approaches a second target concentration lower than the target concentration, or the ozone supply unit 5 is brought into a state of supplying low-concentration ozone, or This control is to stop the ozone supply unit 5 .

The third control may be control different from the second control, or may be the same control as the second control. That is, the control unit 12 may or may not change the content of control when shifting from the second control to the third control. As an example where the third control differs from the second control, for example, the ozone supply unit 5 may be stopped in the second control, and the ozone supply unit 5 may supply low-concentration ozone in the third control. As an example in which the third control is the same control as the second control, for example, the ozone supply unit 5 is controlled to supply low-concentration ozone in the second control, and the ozone supply unit 5 is changed to low-concentration ozone in the third control. of ozone may be maintained.

The control unit 12 and the abnormality determination unit 14 of the ozone generator 1 cooperatively execute the processing shown in FIG. 3 when the start condition is satisfied. The start condition is, for example, that the operation unit 16 performs a start operation.

The control unit 12 starts the above-described first control in step S10 when the start condition is satisfied. After starting the first control, the control unit 12 determines in step S11 whether or not the above-described determination condition is satisfied. When the control unit 12 determines that the determination condition is not satisfied (No in step S11), the process returns to step S11. In other words, the control unit 12 repeatedly determines whether the determination condition is satisfied until the determination condition is satisfied.

When the control unit 12 determines that the determination condition is satisfied (Yes in step S11), the control unit 12 stops the first control and starts the second control in step S12. The abnormality determination unit 14 starts the operation of the timer in step S13. In step S14, the abnormality determination unit 14 determines whether or not a predetermined period of time has elapsed based on the timer operated in step S13. When the abnormality determination unit 14 determines that the predetermined period has not passed (No in step S14), the process returns to step S14. In other words, the abnormality determination unit 14 repeatedly determines whether or not the predetermined period has elapsed until it determines that the predetermined period has elapsed.

If the abnormality determining unit 14 determines that the predetermined period has passed (Yes in step S14), in step S15 it determines whether the degree of decrease in the detected concentration exceeds the threshold. When the abnormality determination unit 14 determines that the degree of decrease in the detected concentration does not exceed the threshold value (No in step S15), the control unit 12 returns to step S10, stops the second control, and performs the first control. Start controlling. When the abnormality determination unit 14 determines that the degree of decrease in the detected concentration exceeds the threshold value (Yes in step S15), in step S16, the control unit 12 stops the second control and performs the third control. to start. That is, the control unit 12 executes the second control when the determination condition is satisfied during the execution of the first control, restarts the first control when the degree of decrease in the detected concentration does not exceed the threshold value, and increases the detected concentration. If the degree of decrease exceeds the threshold, the ozone supply unit 5 is set to supply low-concentration ozone, or the ozone supply unit 5 is stopped.

1-3. Effects of the Ozone Generator of the First Embodiment The following description relates to the effects of the ozone generator 1 of the first embodiment.
Since the detection unit 10 detects the ozone concentration by an electrochemical method, it may be affected by gases other than ozone (for example, cigarette smoke, incense, etc.). As a result, the detected concentration may deviate from the actual concentration. If the ozone supply unit 5 is feedback-controlled so that the detected concentration approaches the target concentration in this state, the actual concentration deviates from the target concentration. In order to determine such an abnormality, the ozone generator 1 executes the second control to stop the first control when the determination condition is satisfied during the execution of the first control. Then, the ozone generator 1 determines abnormality based on the degree of change in the detected concentration from when the determination condition is satisfied until a predetermined period elapses. The detection unit 10 that detects the ozone concentration by an electrochemical method has a characteristic that the higher the actual concentration, the more easily the detected concentration decreases. Therefore, when the first control is stopped, the degree of change in the detected density varies depending on the actual density. Based on this degree of change, the ozone generator 1 can determine an abnormality in which the actual concentration during feedback control deviates from the target concentration.

Further, in the second control, the ozone generator 1 controls the ozone supply unit 5 to supply low-concentration ozone or stops the ozone supply unit 5, and a predetermined period of time has elapsed since the determination condition was satisfied. Abnormality is determined based on the degree of decrease in the detected density. Therefore, the ozone generator 1 can determine an abnormality while suppressing an increase in the ozone concentration in the external space 90 .

Furthermore, the ozone generator 1 determines that it is abnormal when determining that the degree of decrease exceeds the threshold. Therefore, the ozone generator 1 can determine an abnormality in which the actual ozone concentration during feedback control is higher than the target concentration.

Further, if the ozone generator 1 determines that the degree of decrease does not exceed the threshold, it restarts the first control, and if it determines that the degree of decrease exceeds the threshold, it reduces the supply of ozone. or can be stopped.

Furthermore, the ozone generator 1 includes a humidifying section 7 . Therefore, the ozone generator 1 can also function as a humidifier.

<Other embodiments>
The present invention is not limited to the embodiments explained by the above description and drawings, and the following embodiments are also included in the technical scope of the present invention. In addition, various features of the embodiments described above and the embodiments described later may be combined in any way as long as they are consistent combinations.

In the above embodiment, an abnormality is determined when it is determined by the ozone generator that the degree of decrease in the detected concentration exceeds the threshold value, but an abnormality may be determined by another method. For example, an abnormality may be determined when it is determined that the degree of decrease in the detected density does not exceed the threshold. Gases other than ozone gas may include not only gases that negatively affect the detected concentration, but also gases that positively affect the detected concentration. When there is a gas that exerts a positive influence, the actual concentration is smaller than the detected concentration, so the degree of decrease is small. As a method for determining such an abnormality, it is conceivable to employ a configuration in which an abnormality is determined when it is determined that the degree of decrease in the detected density does not exceed a threshold value.

In the above embodiment, when the degree of decrease exceeds the threshold, the ozone generator is configured to perform common control regardless of the degree of excess in the third control. It may be configured to perform different control depending on the For example, the control unit of the ozone generator controls the ozone supply unit so that the ozone supply amount decreases as the degree of decrease increases when the ozone supply unit is caused to supply low-concentration ozone in the third control. good too. The method of determining the ozone supply amount is, for example, to store correspondence data indicating the correspondence relationship between the degree of decrease and the ozone supply amount set to decrease as the degree of decrease increases, and store this correspondence data and the actual degree of decrease. It may be a method of determining based on and. The correspondence data may be a table or an arithmetic expression.

In the above embodiment, the ozone supply section and the humidification section are configured separately, but the ozone supply section may include the humidification section. For example, the ozone supply unit may be configured to generate ozone water by electrolyzing raw material water and atomize or vaporize it. With this configuration, it is possible to humidify with the supply of ozone. As a configuration for atomizing or vaporizing the ozone water, the configuration of the humidifying section described in the above embodiment can be adopted. Further, although the ozone generator of the above embodiment has a configuration including a humidifying section, it may have a configuration without a humidifying section.

In the above embodiment, as the second control for stopping the first control, the ozone generator controls the ozone supply unit so as to supply low-concentration ozone or stops the ozone supply unit. may be configured. For example, the ozone generator may control the ozone supplier to supply ozone at a concentration higher than the target concentration. “High concentration” means that the amount of ozone supplied is larger than the amount of ozone supplied from the ozone supply unit 5 when the determination condition is satisfied during execution of the first control.

It should be noted that the embodiments disclosed this time should be considered as examples in all respects and not restrictive. The scope of the present invention is not limited to the embodiments disclosed this time, and includes all modifications within the scope indicated by the claims or within the scope equivalent to the claims. is intended.

DESCRIPTION OF SYMBOLS 1... Ozone generator 5... Ozone supply part 7... Humidification part 10... Detection part 12... Control part 14... Abnormality determination part 90... External space

Claims (6)

an ozone supply unit that supplies ozone to an external space;
a detection unit that detects ozone concentration by an electrochemical method;
a first control for feedback-controlling the ozone supply unit so that the ozone concentration detected by the detection unit approaches a target concentration; and stopping the first control when a determination condition is satisfied during execution of the first control. a second control that causes the
an abnormality determination unit that determines an abnormality based on the degree of change in the ozone concentration detected by the detection unit from when the determination condition is established until a predetermined period elapses;
Ozone generator with. wherein, in the second control, the control unit controls the ozone supply unit to supply low-concentration ozone or stops the ozone supply unit;
The ozone generator according to claim 1, wherein the abnormality determination unit determines the abnormality based on the degree of decrease in the ozone concentration detected by the detection unit from when the determination condition is established until the predetermined period elapses. . The ozonizer according to claim 2, wherein the abnormality determination unit determines that there is an abnormality when it determines that the degree of decrease exceeds a threshold value. The control unit executes the first control when it is determined that the degree of decrease does not exceed the threshold, and is detected by the detection unit when it is determined that the degree of decrease exceeds the threshold The ozone supply unit is feedback-controlled so that the concentration approaches a second target concentration lower than the target concentration, the ozone supply unit is brought into a state of supplying low-concentration ozone, or the ozone supply unit is stopped. 4. The ozone generator according to claim 3, wherein the third control is executed to bring the ozone generator into a state where the When the ozone supply unit is caused to supply low-concentration ozone in the third control, the control unit controls the ozone supply unit such that the greater the degree of decrease, the smaller the amount of ozone supplied. 5. The ozone generator according to 4. The ozone generator according to any one of claims 1 to 5, comprising a humidifying section that humidifies the external space.

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