JPH0825723B2 - Ozone generator - Google Patents

Description

The present invention relates to an ozone generator used for deodorization or sterilization in a refrigerator or the like.

<Prior Art> Conventionally, an ozone generator is arranged and used in a refrigerator in order to decompose an odor generated from food stored in a refrigerator and to sterilize the inside of the refrigerator. Ozone generators generally synthesize ozone from oxygen in the air by silent discharge.

However, the amount of ozone generated due to the silent discharge decreases as the humidity increases, as shown in FIG. Therefore, when the humidity inside the refrigerator is high, such as immediately after opening and closing the door of the refrigerator, silent discharge is less likely to occur due to dew condensation on the surface of the discharge electrode, and the ozone generation efficiency not only decreases. In addition, the amount of harmful NO _x is increased, which accelerates the corrosion of the equipment, and causes a problem of air pollution.

In order to solve this problem, a configuration is known in which a heater is arranged near the discharge electrode to dehumidify the raw material air near the electrode. With such a configuration, when the power is turned on, the heater is energized for, for example, about 3 minutes and then the silent discharge is started. After that, when the refrigerator door is opened, the silent discharge is stopped and the refrigerator door is closed. After being discharged, the silent discharge is generally restarted. In such a configuration, the discharge electrode is kept at a high temperature, dew condensation on its surface is prevented, and silent discharge for ozone generation is stably performed, so that ozone can be efficiently generated.

On the other hand, in the ozone generator, in order to reduce the generation of NO _x as much as possible, it is detected whether or not the silent discharge is being stably performed, and when the discharge is defective, the ozone generator is operated. There may be a case where an abnormality detection mechanism that stops the operation is provided. Abnormality detection by monitoring the silent discharge state described above is performed, for example, by monitoring the discharge current, and the predetermined abnormality detection in which the discharge current is lower than the value in the normal state (when stable silent discharge is performed) If it is less than the level, it is determined to be abnormal, and the power supply for silent discharge is stopped.

<Problems to be Solved by the Invention> FIG. 6 shows a temporal change in the discharge current when the humidity is high (90% and 95%) after the operation of the ozone generator is started. However, in order to simplify the explanation, FIG. 6 shows a case where the above abnormality detection mechanism is not operated, and the discharge current of the discharge current when the power for silent discharge is supplied to the discharge electrode immediately after the start of the operation is shown. The time change is shown. The curve l11 shows the case where the humidity is 90%,
Curve l12 shows the case where the humidity is 95%. Further, the abnormality detection level L in the abnormality detection mechanism is also shown at the same time.

With the start of operation of the ozone generator, the heater placed near the discharge electrode starts to be energized at the same time, and when the power for silent discharge is supplied in this state, the dew condensation on the electrode surface disappears with the passage of time. Moreover, since the humidity of the air near the electrodes decreases, the discharge current gradually increases. As a matter of course, the higher the humidity, the slower the increase in discharge current.

For example, when the humidity is 95% (curve l12), since the discharge current is below the abnormality detection level L in the period T31 until the time t31 after the start of operation, if the abnormality detection mechanism described above is included in the period T31. When the abnormality detection operation is started by the device, the device is determined to be in an abnormal state and the operation of the device is stopped. When the abnormality detection mechanism starts the abnormality detection operation after the time t31, the discharge current is higher than the abnormality detection level L, so that the abnormality state is not determined.

Therefore, in the conventional technique in which the remaining heat time by the heater immediately after the start of operation is constant, the heater is energized until the time t31, and then the abnormality detection mechanism is activated along with the supply of power to the discharge electrode. Even if the ozone generation operation can be performed normally, for example, if the constant energization time is set to be shorter than the length of the period T31, it is determined that the discharge state is abnormal and then There will be a problem that the driving will be stopped.

On the other hand, if an excessively long remaining heat time is set, the rise time for starting ozone generation due to silent discharge becomes long, and there is a problem that power is wasted by the heater.

Therefore, the present invention solves the above-mentioned technical problems, and makes it possible to properly stop the operation in the event of an abnormality and to allow the residual heat from the heater to satisfactorily respond to various situations. An object is to provide a generator.

<Means for Solving the Problems> An ozone generator of the present invention for achieving the above object is an ozone generator that generates ozone from raw material air by silent discharge, and is for discharge that causes the silent discharge. An electrode, a heater that heats the discharge electrode and dehumidifies the raw material air in the space near the discharge electrode, a high-voltage power supply that supplies a high voltage for discharge to the discharge electrode, and this high-voltage power supply discharges Abnormality detection means for starting an abnormality detection operation after starting to supply a high voltage for discharge to the discharge electrode, and outputting an abnormality detection signal when the discharge current in the discharge electrode is less than a predetermined value; When the signal is derived, while stopping the output of the high voltage for discharge from the high voltage power supply,
After a predetermined time, the high voltage power supply control means for outputting the high voltage for discharging to the high voltage power supply again and the control means for stopping the operation of the apparatus when the abnormality detection signal is output for a predetermined number of times are included.

<Operation> According to the above configuration, when a high voltage from the high-voltage power supply is supplied to the discharge electrode by the control of the high-voltage power supply control means, silent discharge does not satisfactorily occur, and the discharge current is low. An abnormality detection signal is output from the detection means. As a result, the high-voltage power supply control means temporarily stops the output of the high voltage from the high-voltage power supply, and restarts the supply of the high voltage after a predetermined time has elapsed.

In this way, when ozone generation by silent discharge is not started even when a high voltage is supplied, the high voltage is repeatedly supplied at predetermined time intervals. Therefore, the silent discharge in the discharge electrode is started when the condition of the electrode surface and the surrounding humidity become appropriate conditions for the discharge due to the heating by the heater. Can be set to an appropriate value corresponding to the state of the discharge electrode.

On the other hand, the operation of the device is not stopped immediately even if the abnormality detection means outputs the above abnormality detection signal, but the operation of the device is stopped when the output of the abnormality detection signal for a predetermined number of times is detected by the control means. To be done. Therefore, when the silent discharge cannot be started due to the residual heat of the heater for a relatively long time, it is finally determined that an abnormality has occurred, and the operation of the device is stopped.

<Examples> Detailed description will be given below with reference to the accompanying drawings showing examples.

FIG. 1 is a block diagram showing the electrical configuration of an ozone generator according to an embodiment of the present invention. This ozone generator
A high voltage for discharge is supplied from the high-voltage power supply 1 to the discharge electrode 3 provided in the ozonizer main body 2 to generate a silent discharge, and the air in the vicinity of the ozonizer main body 2 is used as a raw material to ozone the oxygen in the air. To generate ozone. The ozonizer main body 2 is provided with a heater 4 for evaporating water droplets attached to the surface of the discharge electrode 3 and dehumidifying the raw material air in the ozonizer main body 2.
Energization of the heater 4 is controlled by a heater control circuit 5.

The high-voltage power supply 1 is controlled by the power supply control circuit 6 to output a high voltage. When the high voltage power supply 1 supplies a high voltage to the discharge electrode 3, the discharge current flowing through the discharge electrode 3 is the discharge current detection circuit 7 connected to the high voltage power supply 1.
Is detected by The output of the discharge current circuit 7 is given to the abnormality detection circuit 8. The abnormality detection circuit 8 determines whether the discharge current is below a predetermined abnormality detection level based on the output of the discharge current detection circuit 7. Find out. When the discharge current is below the abnormality detection level,
An abnormality detection signal indicating that an abnormality has occurred in the ozonizer main body 2 is led to the line 9.

The abnormality detection signal derived on the line 9 is supplied to the power supply control circuit 6 and also to the counter 10 that counts the number of times the abnormality detection signal is output. The power supply control circuit 6 inhibits the high voltage output of the high voltage power supply 1 in response to the abnormality detection signal. The counter 10 overflows at a predetermined count value N (for example, 10).
The signal that indicates whether 10 is in the overflow condition is
An abnormality detection reset circuit is provided to the run / stop circuit 11 that switches the device between the operating state and the stopped state.
It is also given to 12.

Whenever the count value of the counter 10 changes, the abnormality detection reset circuit 12 resets the abnormality detection circuit 8 from the line 13 to reset the abnormality detection state when the counter 10 is not in the overflow state. Give a signal. In addition, the operation / stop circuit 11 switches the device between the operating state and the stopped state in response to turning on / off of the operation switch 14, and when the counter 10 overflows, the operation of the device is forced. Stop. A control means is configured to include the run / stop circuit 11 and the counter 10.

A control signal for instructing whether to operate or stop the device is derived from the run / stop circuit 11, and this control signal is input to the delay timer circuit 15. The delay timer circuit 15 starts its timing operation in response to a control signal instructing the start of operation, measures a predetermined time T1 (for example, 1.2 seconds), and when the predetermined time T1 expires, the high-voltage power supply A signal for generating a high voltage from 1 is supplied to the power supply control circuit 6. The reset signal from the abnormality detection reset circuit 12 is also input to the delay timer circuit 15, and when the reset signal is given in the operating state, the clocking operation is started in response to the input of the reset signal. Then, when the time of the predetermined time T1 has expired, a signal for generating a high voltage from the high voltage power supply 1 is given to the power supply control circuit 6. In this embodiment, the high-voltage power supply control means is configured to include the delay timer circuit 15 and the power supply control circuit 6.

The output of the delay timer circuit 15 is also given to the abnormality detection prohibition timer circuit 16 which prohibits the abnormality detection operation in the abnormality detection circuit 8 for a predetermined time T2 (for example, 1 second). As a result, the abnormality detection in the abnormality detection circuit 8 is prohibited during the period until the predetermined time T2 elapses after the delay timer circuit 15 outputs the signal instructing the generation of the high voltage. It is possible to prevent erroneous abnormality detection during the rising period of the discharge current immediately after the start of supply.

FIG. 2 is a timing chart for explaining the operation under normal conditions. 2 (a) shows the output signal of the run / stop circuit 11, FIG. 2 (b) shows the energized state of the heater 4, FIG. 2 (c) shows the operation of the high-voltage power supply 1, and FIG. Figure (d) shows the change of the discharge current flowing through the discharge electrode 3,
FIG. 2E shows the output of the abnormality detection circuit 8.

When the operation switch 14 is turned on at time t1 and the operation / stop circuit 11 derives a control signal for instructing the start of operation, the heater control circuit 5 starts energizing the heater 4 in response to this.

The delay timer circuit 15 responds to the control signal from the operation / stop circuit 11 and derives a signal for starting the output of the high voltage from the high voltage power source 1 after measuring the predetermined time T1 from the time t1. Then, as a result, the output of the high voltage from the high voltage power supply 1 is started at the time t2 after the elapse of the predetermined time T1 from the time t1.

As a result, when the silent discharge starts between the discharge electrodes 3 in the period from time t2, the discharge current detection circuit 7
The discharge current detected at 1 rapidly increases as indicated by reference numeral l1.

The abnormality detection circuit 8 performs the abnormality detection operation at time t3 when the predetermined time T2 measured by the abnormality detection prohibition timer circuit 16 has elapsed from time t2. At this time t3, since the discharge current is above the abnormality detection level LL, the second
As shown in FIG. 6E, the abnormality detection signal is not derived.

FIG. 3 is a timing chart for explaining the operation at the time of abnormality, and FIGS. 3 (a) to 3 (e) are operations corresponding to FIGS. 2 (a) to 2 (e), respectively. Is shown. When the operation switch 14 is turned on at time t11 and the operation / stop circuit 11 outputs a control signal for instructing the operation start, the heater control circuit 5 starts energizing the heater 4.

Then, the time t after the elapse of the predetermined time T1 from the time t11
In response to the signal from the delay timer circuit 15, the power supply control circuit 6 causes the high voltage power supply 1 to start outputting a high voltage.

However, when silent discharge cannot be generated due to abnormality such as dew condensation on the discharge electrode 3, the abnormality detection prohibition timer circuit 16 starts timing from time t12 as shown in FIG. 3 (d). Even after the elapse of the predetermined time T2, the discharge current flowing through the discharge electrode 3 does not increase, so that the abnormality detection circuit 8 detects the abnormality and derives the abnormality detection signal indicated by reference numeral 12 to the line 9. As a result, the count value of the counter 10 is incremented by 1. In response to the counting operation of the counter 10, the abnormality detection reset circuit 12 outputs a reset signal to the line 13, so that the abnormality detection state in the abnormality detection circuit 8 is reset at time t13.

In response to the reset signal from the abnormality detection reset circuit 12, the delay timer circuit 15 restarts counting the predetermined time T1. Then, at a time t14 after a lapse of a predetermined time T1 from the time t13, the high voltage from the high voltage power supply 1 is supplied to the discharge electrode 3 again. When the abnormality cannot be eliminated even by the heating by the heater 4 in the period until the second high voltage is supplied, and therefore the silent discharge cannot be generated, from the time t15 when the predetermined time T2 has elapsed from the time t14. Anomaly detection circuit 8
Even when an abnormality is detected by the
Since it has not reached LL, it is determined to be abnormal, and thus the abnormality detection signal indicated by reference numeral 13 is derived on the line 9.

Then, as with the operation during the period from time t12, the counter 1
The count value of 0 is increased by 1, and in response thereto, the abnormality detection reset circuit 12 derives the reset signal on the line 13.

When such an operation is repeatedly performed and the silent discharge cannot be started even when the high-voltage discharge electrode 3 is supplied a predetermined number of times N, the counter 10 counts the predetermined value N and overflows. In response to time t1
At 6, the start / stop circuit 11 stops the operation of the device.

As described above, when the silent discharge cannot be immediately generated by the high voltage supply, when the high voltage is repeatedly supplied to the discharge electrode 3 at a time interval of time (T1 + T2) and the high voltage is supplied N times. Even when the heater 4 is energized for a period of approximately N × (T1 + T2), if a silent discharge cannot be generated, it is finally determined that an abnormality has occurred. As a result, the operation of the device will be stopped.

Due to the above-described operation, when the electrode 3 is not condensed and the humidity of the raw material air in the region near the ozonizer 4 is sufficiently low, the heater 4 is operated for a short time (for example, a predetermined time T1). It is possible to start the silent discharge and quickly start the ozone generation after the energization to.

Further, since the high voltage is repeatedly supplied at relatively short time intervals (approximately (T1 + T2) time intervals), residual heat is generated by the heater 4 corresponding to the state of the discharge electrode 3 and the humidity of the raw material air. At this point, silent discharge can be generated, power is not wastefully consumed, and the rise time for ozone generation does not unnecessarily increase.

Furthermore, when the abnormal state cannot be eliminated by energizing the heater 4 for a relatively long time (approximately N × (T1 + T2) time), it is finally determined that an abnormality has occurred. The operation of the device will not be stopped by a slight abnormality that can be eliminated by the residual heat due to. As a result, the operation of the apparatus is stopped only when an abnormality that cannot be eliminated by the residual heat from the heater 4 occurs, and it is possible to prevent the operation from being mistakenly stopped in the case of a slight abnormality.

FIG. 4 is a graph showing the measurement results of the inventor of the present invention, which investigated the relationship between the state of the discharge electrode 3 and the residual heat time by the heater 4 required for stable discharge. For this measurement,
An ozone generation panel having a structure in which one discharge electrode was embedded in a dielectric and the other discharge electrode was formed on the surface was used. As the measurement conditions, when the ozone generating panel is immersed in water and the water on the panel surface is wiped off (measurement point A in FIG. 4), the ozone generating panel is cooled in a room at 5 ° C. The case of dew condensation (measurement point B in FIG. 4) and the case where the panel was immersed in water and taken out and the surface water was not wiped off (measurement point C in FIG. 4) were set. .

In FIG. 4, the diameter of the water droplets on the panel surface and the high voltage power supply from the high voltage power supply 1 are continuously supplied without any abnormality detection.
The result of measuring the relationship with the time required for the discharge current to exceed the abnormality detection level in the abnormality detection circuit 8 is shown. The state of the measurement point A corresponds to the case where the panel surface is wet, the state of the measurement point B corresponds to the state of dew condensation on the panel, and the state of the measurement point C corresponds to, for example, the cleaning of the panel. It corresponds to the condition that the panel surface is wet such as when the surface is not wiped off later. Therefore, in the state of measurement points A and B, abnormality detection is not performed and measurement point C
In this state, it is preferable to perform abnormality detection.

Therefore, in the ozone generator of this embodiment, it is preferable to select the above-mentioned predetermined times T1 and T2 and the predetermined number of times N, for example, as follows.

T1 = 1.2 (seconds) T2 = 1.0 (seconds) N = 10 If the values are selected in this way, the length of the period from time t11 to time t16 in FIG. 3 is approximately N × (T1 + T2) = 22 (seconds). ). As a result, in the case of the measurement points A, B, etc. in FIG. 4, a relatively short time interval (T1 + T2) = 2.2 (seconds) is opened while the heater 4 is energized, and high voltage is repeatedly supplied. By doing so, it is possible to provide the heater 4 with an optimum remaining heat time, and thereafter to start ozone generation by silent discharge. On the other hand, when the silent discharge cannot be generated even by supplying the high voltage for the predetermined number of times N, that is, for a relatively long time N × (T1 + T2) = 22 (seconds)
If the state of the electrode 3 cannot be brought to a state in which silent discharge can be generated by the residual heat of the device, the operation of the device is stopped. The device will be shut down as it happens.

The present invention is not limited to the above embodiment. For example, the predetermined time set in the above embodiment
T1, T2, the predetermined number of times N, etc. may be appropriately changed as necessary. Various other design changes can be made without departing from the scope of the present invention.

<Effects of the Invention> As described above, according to the ozone generator of the present invention, the silent discharge in the discharge electrode causes the condition of the surface of the electrode and the humidity around the electrode to give an appropriate condition for the discharge. As a result, the remaining heat time by the heater can be set to an appropriate value corresponding to the state of the discharge electrode. Thus, when the state of the discharge electrode is sufficient for a short residual heat time, silent discharge can be promptly started to generate ozone. Further, when a long remaining heat time is required, such a remaining heat time can be given to surely generate ozone by silent discharge. Therefore, there is an effect that it is possible to prevent wasteful power consumption in the heater.

On the other hand, when the control means detects the output of the abnormality detection signal for the predetermined number of times, the operation of the device is stopped, so that the silent discharge cannot be started even by the remaining heat of the heater for a relatively long time. In this case, the operation of the device can be stopped to prevent an accident from occurring.

Further, since the operation is stopped for the first time when the abnormality detection signal is output a predetermined number of times, the operation of the apparatus is not accidentally stopped in the case of a slight abnormality that can be eliminated by the residual heat from the heater.

[Brief description of drawings]

FIG. 1 is a block diagram showing an electrical configuration of an ozone generator of an embodiment of the present invention, FIG. 2 is a timing chart showing an operation at a normal time, FIG. 3 is a timing chart showing an operation at an abnormal time, FIG. 4 is a graph showing the measurement result of the relationship between the state of the discharge electrode 3 and the remaining heat time until stable discharge, FIG. 5 is a graph showing the relationship between humidity and ozone generation amount, and FIG. 6 is when humidity is high. FIG. 6 is a diagram showing a change in discharge current with respect to heating time by a heater in FIG. 1 ... High-voltage power supply, 3 ... Discharge electrode, 4 ... Heater, 6
...... Power supply control circuit, 7 ... Discharge current detection circuit, 8 ... Abnormality detection circuit, 10 ... Counter, 11 ... Run / stop circuit,
12 …… Abnormality detection reset circuit, 15 …… Delay timer circuit,
16 …… Abnormality detection prohibition timer circuit

Claims (1)

[Claims] 1. An ozone generator for generating ozone from raw material air by silent discharge, comprising: a discharge electrode (3) for generating the silent discharge; and a heating of the discharge electrode (3). The heater (4) for dehumidifying the raw material air in the space near the working electrode (3), the high-voltage power supply (1) for supplying a high discharge voltage to the discharge electrode (3), and the high-voltage power supply (1) An abnormality in which an abnormality detection operation is started after the high voltage for discharge is started to be supplied to the discharge electrode (3), and an abnormality detection signal is output when the discharge current in the discharge electrode (3) is less than a predetermined value. The detection means (8) and the output of the high voltage for discharge from the high voltage power supply (1) are stopped when the abnormality detection signal is derived, and after a predetermined time, the high voltage power supply (1) is restarted. The high voltage for discharge is output to That high-voltage power supply control means (6, 15)
And an ozone generating device comprising: a control means (10, 11) for stopping the operation of the device when the abnormality detection signal is output a predetermined number of times.