JP6465849B2 - Long-term static eliminator - Google Patents

Description

  The present invention relates to a static eliminator that simultaneously releases positive and negative ions.

Conventionally, a device provided with a plurality of electrode needles has been known as a static elimination device that simultaneously releases positive and negative ions.
As this type of device, positive DC high voltage is applied to half of the plurality of electrode needles, and negative DC high voltage is applied to the other half of the electrode needles, thereby generating positive and negative ions simultaneously. There was something that released it toward the static elimination object.
Such electrode needles wear and deteriorate due to corrosion or sputtering due to long-term use, but when the electrode needles deteriorate, the amount of ion generation decreases. In particular, the positive electrode needle to which a positive DC high voltage is applied is more likely to deteriorate than the negative electrode needle to which a negative DC high voltage is applied, and the amount of ion generation is significantly reduced accordingly. Are known. Therefore, if the usage time is increased, there is a difference in the amount of ions generated between the positive electrode needle and the negative electrode needle. As a result, there is a problem that the ion balance is lost.
If the ion balance is greatly disrupted, it may take time for static elimination, or the object to be neutralized may be reversely charged, and the target static elimination may not be achieved.

In order to solve such a problem, a static eliminator shown in Patent Document 1 is known.
In this conventional static eliminator, the electrode needles are divided into two groups.
Then, a first polarity pattern in which a positive DC high voltage is applied to the first group and a negative DC high voltage is applied to the second group and a second polarity pattern in which the polarity is reversed are alternately executed. At that time, the discharge current value of each group is detected. When the detected difference between the first and second groups of discharge current values is greater than a predetermined value, the first and second polarity patterns are switched.
As described above, when the deterioration of the electrode needles of one group progresses and the difference in the discharge current value between the first and second groups becomes larger than a predetermined value, the discharge currents of both groups are switched by switching the polarity pattern. The difference between the values is prevented from increasing, and the difference in the amount of ions generated is prevented from increasing.

Japanese Patent Laying-Open No. 2015-088427

The conventional apparatus detects the discharge current values of the first and second groups of electrode needles, and keeps the ion balance by preventing the difference from increasing.
However, the discharge current value changes not only when the tip of the electrode needle is corroded or shortened due to corrosion, but also when fine foreign matter adheres to the vicinity of the tip.

FIG. 4 is an enlarged view of the distal end side of the electrode needle 1, (a) is a new article, and (b) is a view showing a state in which the deterioration after use for a long time has progressed.
As shown in FIG. 4B, the tip 2 of the electrode needle 1 is worn and deformed due to long-time use, and its entire length is shortened. In such a worn and deteriorated electrode needle, the discharge state becomes unstable and the amount of ions generated decreases.
Furthermore, fine foreign matter 3 in the atmosphere is likely to adhere to the vicinity of the tip 2 due to the action of an electric field. However, the foreign material 3 is not fixed to the surface of the electrode needle 1 but is swayed or scattered from the surface and scattered.

As described above, when the foreign matter 3 is attached, the foreign matter 3 is shaken, the foreign matter 3 is detached or reattached in the vicinity of the tip 2, the discharge state is changed each time, and the discharge current value is slightly changed. Will do. The conventional static eliminator controls the polarity pattern switching timing based on the delicately changing discharge current value.
As described above, in the conventional static eliminator, the switching of the polarity pattern is controlled based on the discharge current value that changes slightly, so that the polarity pattern is frequently switched.
For example, if the foreign matter 3 adheres to the vicinity of the tip 2 of the electrode needle 1, or the attached foreign matter 3 leaves or reattaches, the deterioration state of the electrode needle itself does not change, but the discharge current The value may change and the polarity pattern may be switched. In particular, the longer the usage time becomes, the more frequently the polarity pattern is switched as the wear of the tip 2 of the electrode needle 1 due to sputtering or the influence of the foreign matter 3 adhering to the vicinity of the tip increases.

  The fact that the polarity pattern is frequently switched means that positive and negative DC high voltages are alternately applied to one electrode needle 1 in a short time, and the applied voltage rises at each switching. It will be. Since the rise of the applied voltage is inevitably delayed, if the switching frequency is increased, the rise of the applied voltage to the electrode needle 1 is delayed and the predetermined high voltage is not reached and is stable. Discharge cannot be sustained. As a result, there arises a problem that the amount of ions generated within a certain period of time decreases, and it takes time for static elimination.

  An object of the present invention is to provide a static eliminator capable of efficiently eliminating static charges while preventing a decrease in the amount of ions generated while preventing a loss of ion balance due to electrode needle deterioration.

This invention, a plurality of electrode needles to produce polarity of ions in response to high DC voltage applied is, a discharge portion which is divided into first and second group, the positive and negative DC with respect to the discharge section A positive / negative high voltage power supply unit that outputs a high voltage, a first polarity pattern in which a positive DC high voltage is applied to the first group and a negative DC high voltage is applied to the second group, and A second DC pattern in which a negative DC high voltage is applied to the first group and a positive DC high voltage is applied to the second group is alternately selected to generate a DC high voltage from the positive / negative high voltage power supply unit. And a control unit for outputting a voltage.
Then, the control unit includes conductive and function to measure the time elapsed from the start of the first or second polarity pattern for Gokuhari, the elapsed time is previously set between 12 to 24 hours Set When the time has been reached, the first polarity pattern and the second polarity pattern are switched, and thereafter, the function of switching the first polarity pattern and the second polarity pattern every 12 to 24 hours, and the first or second from the start of the polarity pattern of the output from the positive and negative high voltage power supply unit in the set time is interrupted, when the subsequent output from the positive and negative high voltage power supply unit is resumed, the upper Symbol polarity a function of maintaining the polarity pattern before the interruption until the elapse of the time difference between the elapsed time and the set time from when switching pattern until the interruption, or when switching the polarity pattern A function for selecting a polarity pattern different from that before the interruption without maintaining the polarity pattern before the interruption when the difference between the elapsed time until the interruption and the set time is equal to or shorter than the predetermined time. And .

According to the first aspect, the time during which the positive DC high voltage is applied to the electrode needles of the first and second groups can be made equal to the time during which the negative DC high voltage is applied. Therefore, it is possible to prevent the deterioration of only a specific group of electrode needles even in a continuous operation for a long time.
Moreover, the present invention, electrostatic elapsed time from start of use to measure the Gokuhari, when the elapsed time reaches the preset time between 12 to 24 hours, first in the first polarity pattern Switches between two polarity patterns. Thereafter, the first polarity pattern and the second polarity pattern are switched every 12 to 24 hours.
Therefore, for example, based on the experimental result of FIG. 3, when 0.005 [mm] is consumed, switching between the first polarity pattern and the second polarity pattern is performed. Under such switching, the maximum width of the electrode needle length imbalance is about 0.005 [mm]. In other words, when the electrode needle to which a positive voltage is applied is consumed by about 0.005 [mm], the voltage applied thereto is switched to the negative electrode, so that the electrode needle to which the positive voltage is applied and the negative electrode needle are negatively applied. The maximum difference in length from the electrode needle to which the voltage is applied is about 0.005 [mm].
As described above, since the unbalance between the length of the electrode needle to which a positive voltage is applied and the length of the electrode needle to which a negative voltage is applied can be suppressed to a range of 0.005 [mm], the ion balance is stabilized. be able to.
In addition, since the switching between the first polarity pattern and the second polarity pattern is performed every 12 to 24 hours, the influence of the rise of the voltage applied to each electrode needle can be ignored, and the ion balance is maintained efficiently. Ion generation becomes possible.
Further, by stopping the neutralization apparatus, even when the power output was interrupted, the positive for each electrode needle, it is possible to reduce the deviation of the application time of the negative DC high voltage, electrode needle degradation Bias can be reduced. As a result, ion balance can be maintained.

1 is a circuit diagram of a first embodiment of the present invention. It is a circuit diagram of a 2nd embodiment. It is the graph which showed the relationship between the discharge time and the change of the length of an electrode needle by the experimental result which confirms the deterioration state of the electrode needle by long-term use. It is an enlarged view of the front end side of an electrode needle, (a) is before use, (b) has shown the state which deteriorated.

The first embodiment shown in FIG. 1 is a static eliminator in which a discharge unit 7 is connected to a positive / negative high voltage power supply unit 4 that outputs a DC high voltage via switch circuits 5 and 6. The discharge part 7 includes a plurality of electrode needles 1a and 1b.
The electrode needles 1a and 1b are metal needle-like electrodes with sharp tips similar to the discharge electrode 1 shown in FIG. All the electrode needles 1a and 1b have the same shape.
However, the electrode needles 1 a and 1 b constituting the discharge unit 7 include a plurality of electrode needles 1 a connected to one switch circuit 5 as a first group A and a plurality of electrode needles 1 a and 1 b connected to the other switch circuit 6. The electrode needle 1b is a second group B. The total number of electrode needles 1a and 1b is not limited, but the number of electrode needles 1a and 1b constituting each group A and B is the same.
Further, a CPU 8 for controlling the switch circuits 5 and 6 is connected to the switch circuits 5 and 6.

The positive / negative high voltage power supply unit 4 includes a DC power supply and an amplifier circuit (not shown), and a positive output terminal 4a that outputs a positive DC high voltage and a negative output terminal that outputs a negative DC high voltage. 4b. These positive and negative output terminals 4 a and 4 b are connected to the switch circuits 5 and 6 by a positive voltage supply line 9 and a negative voltage supply line 10.
The switch circuit 5 is a switch circuit that connects the first group A to the positive voltage supply line 9 or the negative voltage supply line 10, and the switch circuit 6 connects the second group B to the positive voltage supply line 9 or A switch circuit connected to the negative voltage supply line 10.

Then, the CPU 8 controls the switch circuits 5 and 6 to switch the polarity of the voltage applied to the first and second groups A and B of the discharge unit 7 at preset time intervals.
Specifically, the switch circuit 5 connects the positive voltage supply line 9 and the first group A, and the switch circuit 6 connects the negative voltage supply line 10 and the second group B, and the switch circuit 5 switches the negative voltage supply line 10 and the first group A, and the switch circuit 6 alternately switches the second polarity pattern connecting the positive voltage supply line 9 and the second group B every set time. I have to.
That is, in this embodiment, the CPU 8 and the switch circuits 5 and 6 constitute the control unit of the present invention for switching the first and second polarity patterns.

As described above, since the polarity of the DC high voltage applied to the first and second groups A and B is switched every set time, the time during which the positive DC high voltage is applied to each group A and B. And the time during which the negative DC high voltage is applied can be made equal. Therefore, it can prevent that only the positive electrode needle deteriorates and ion balance is lost.
In addition, in the first embodiment, since the polarity pattern is not switched based on a slightly changing discharge current value as in the conventional static eliminator, the first and second polarity patterns are switched more frequently than necessary. Never done. Therefore, the influence of the delay of the rising of the applied voltage can be reduced, and efficient neutralization can be performed.
Furthermore, there is also an advantage that the structure can be simplified as compared with the conventional device because the means for detecting the discharge current value is not required.

The second embodiment shown in FIG. 2 is different from the first embodiment of FIG. 1 in the connection positions of the switch circuits 5 and 6 and the positive / negative high voltage power supply unit 4. However, the same code | symbol as FIG. 1 is used for the component which has the function similar to 1st Embodiment.
In the second embodiment, the power supply unit 4 is provided between the discharge unit 7 including the first and second groups A and B of the electrode needles 1 a and 1 b and the switch circuits 5 and 6.
The power supply unit 4 includes positive high voltage circuits 11 and 14 that output a positive DC high voltage, and negative high voltage circuits 12 and 15 that output a negative DC high voltage. Each high voltage circuit includes, for example, an amplifier circuit such as a Cockcroft-Walton circuit and an oscillation circuit, and outputs a DC high voltage.

The switch circuit 5 is connected to the positive high-voltage circuit 11 and the negative high-voltage circuit 12, and the output sides of the positive and negative high-voltage circuits 11 and 12 are first connected by a voltage supply line 13. Connected to group A.
On the other hand, the positive high voltage circuit 14 and the negative high voltage circuit 15 are connected to the switch circuit 6, and the output side of these positive and negative high voltage circuits 14 and 15 is connected to the second group B by the voltage supply line 16. It is connected to the.

Further, a CPU 8 is connected to the switch circuits 5 and 6, and the CPU 8 switches the switch circuits 5 and 6 at preset time intervals so that the positive and negative high voltage circuits 11, 12, 14 are switched. , 15 is output to switch the first and second polarity patterns.
The CPU 8 and the switch circuits 5 and 6 constitute a control unit of the present invention.

The specific operation of the first and second polarity patterns is as follows.
When the CPU 8 selects the first polarity pattern, the switch circuit 5 connects the CPU 8 and the positive high voltage circuit 11 to operate the positive high voltage circuit 11, and the switch circuit 6 is connected to the CPU 8. The negative high voltage circuit 15 is connected to the negative high voltage circuit 15 to operate. As a result, a positive DC high voltage is applied to the first group A via the voltage supply line 13 from the positive high voltage circuit 11, and the voltage supply line 16 from the negative high voltage circuit 15 to the second group B. A negative high DC voltage is applied via

Further, when a preset set time elapses after selecting the first polarity pattern, the CPU 8 controls the switch circuits 5 and 6 so that the second polarity pattern is executed.
In the second polarity pattern, a control signal output from the CPU 8 operates the CPU 8 and the negative high-voltage circuit 12 via the switch circuit 5 and also supplies a positive high-voltage circuit 14 via the switch circuit 6. To work. As a result, a negative DC high voltage is applied to the first group A from the negative high voltage circuit 12 via the voltage supply line 13, and a voltage from the positive high voltage circuit 14 is applied to the second group B. A positive DC high voltage is applied via the supply line 16.

As described above, also in the second embodiment, since the polarity of the DC high voltage applied to the first and second groups A and B is switched every set time, a positive DC high voltage is applied to each group A and B. Can be made equal to the time during which a negative high DC voltage is applied. Therefore, it can prevent that only the positive electrode needle deteriorates and ion balance is lost.
Further, the static eliminator of the second embodiment does not require a discharge current value detecting means, and therefore has an advantage that the device structure can be simplified as compared with the conventional case.

Below, the confirmation experiment which confirms the deterioration condition of the electrode needle | hook 1a, 1b by discharge is demonstrated.
This confirmation experiment was conducted using a plurality of electrode needles made of tungsten having a total length of 15 [mm] in a new state. The plurality of electrode needles are divided into two groups, +6 [kV] is applied to one group of electrode needles for discharge, and −6 [kV] is applied to the other group for discharge. The length was measured.

The result is as the graph shown in FIG. 3 which showed the change of discharge time and the length of an electrode needle. The solid line in FIG. 3 is a graph showing the change in the length of the negative electrode needle to which −6 [kV] is applied, and the broken line is the change in the length of the positive electrode needle to which +6 [kV] is applied. It is a graph. In addition, the length of the electrode needle shown in FIG. 3 is an average of the measured values of a plurality of electrode needles constituting each group.

From this result, the electrode needle of the negative electrode, after the discharge time has elapsed over 100 days was found that you do not change almost in length.
On the other hand, the electrode needle of the positive electrode was 14.75 [mm] when 50 days passed, and was 0.25 [mm] shorter than the new one. However, as is clear from FIG. 3, it was found that the electrode needle of the positive electrode hardly deteriorates after 50 days.
Therefore, the number of days after the 50th day when the progress of the deterioration of the positive electrode needles was excluded from the calculation of the average value, and the average deterioration state of the positive electrode needles for 50 days from the start of the discharge was calculated. As a result, it was found that the positive electrode needles were shortened by an average of 0.005 [mm] per day.
As described above, it was confirmed that the change amount of the positive electrode needle, which is easily deteriorated, is small in one day. Therefore, the above set time set in the CPU 8 is set to 1 day, that is, 24 hours to prevent the ion balance from being lost due to deterioration of the electrode needle .
If the set time is set to, for example, one day or half a day, the influence of the rising delay of the DC high voltage applied to the discharge unit 7 can be ignored, and the amount of ion generation is not insufficient.

Although details are omitted, the result of the above confirmation experiment using an electrode needle made of Inconel (registered trademark) instead of the electrode needle made of tungsten is almost the same as described above. The amount of change in length was about 0.005 [mm] per day, and the amount of change in the negative electrode needle was 0.002 [mm] per day.
From this result, it was found that even when an electrode needle made of Inconel (registered trademark) is used, it is not necessary to shorten the setting time for switching between the first and second polarity patterns.

Note that the static eliminator of the first and second embodiments may start any one of the first and second polarity patterns at the start of operation at any time. Or by randomly selecting and starting, it is possible to further reduce the bias of application time of positive and negative DC high voltage.
In addition, when the static eliminator is stopped and the output from the positive / negative high-voltage power supply unit 4 is interrupted within the set time, after the operation is resumed, the time is measured following the elapsed time before the interruption. The polarity pattern before the interruption may be maintained for the difference between the previous elapsed time and the set time. In this way, even if the static eliminator is stopped at any point in time, the time for which the first and second polarity patterns are maintained becomes equal, and the ion balance can be maintained more strictly.

However, if the remaining time up to the set time is very short when the operation of the static eliminator is interrupted, do not maintain the polarity pattern before the interruption and select a different polarity pattern from that before the interruption when the operation is resumed. Also good. Although the remaining time at the time of interruption is short, if the time measurement is continued from before interruption when operation is resumed, the polarity pattern will be switched in a short time. This is because there is a possibility that ion generation becomes unstable due to stabilization.

The set time set in the CPU 8 needs to be determined within a range in which the difference in the degree of deterioration of the electrode needles between the positive electrode group and the negative electrode group is not so large.
The deterioration of the electrode needle depends on the material of the electrode, the tip shape, the applied voltage value, the external environment, etc., and the set time may be set in accordance with them.

  Over a long period of time, it is possible to maintain the same deterioration state of the positive electrode needle and the negative electrode needle, and to maintain efficient charge removal.

A 1st group B 2nd group 1 Electrode needles 1a, 1b Electrode needles 4 Positive / negative high voltage power supply units 5, 6 (constituting control unit) Switch circuit 7 Discharging unit 8 (constituting control unit) CPU
11 Positive side high voltage circuit 12 Negative side high voltage circuit 14 Positive side high voltage circuit 15 Negative side high voltage circuit

Claims (1)

A plurality of electrode needles that generate ions of polarity according to the applied DC high voltage, the discharge unit divided into the first and second groups,
A positive / negative high voltage power supply unit that outputs positive and negative DC high voltages to the discharge unit;
A first polarity pattern in which a positive DC high voltage is applied to the first group and a negative DC high voltage is applied to the second group; and a negative DC high voltage is applied to the first group A control unit that alternately selects a second polarity pattern in which a positive DC high voltage is applied to the second group and outputs a DC high voltage from the positive / negative high voltage power supply unit,
And the control unit,
A function of measuring elapsed time, for each predetermined set time between 12 to 24 hours, a function of switching between the first polarity pattern and a second polarity pattern,
When the output from the positive / negative high voltage power supply unit is interrupted and then the output from the positive / negative high voltage power supply unit is resumed,
A function of maintaining the polarity pattern before the interruption until the time difference between the elapsed time from the switching of the polarity pattern to the interruption and the set time elapses;
When the difference between the elapsed time from the switching of the polarity pattern to the interruption and the set time is equal to or shorter than a predetermined time shorter than the set time, the polarity pattern before the interruption is not maintained, and The ability to select different polarity patterns ,
Long-term static eliminator with

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