JP2010055848A - Static eliminator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To maintain balance of a positive/negative ions generated amount due to wear of an electrode for ion generation in the case it is used for a long period. <P>SOLUTION: A corona discharge type static eliminator by direct current voltage is equipped with the static eliminator body, a positive discharge electrode which is installed at the static eliminator body and has a plurality of pieces of positive discharge needles to form positive ions when a positive voltage is applied, and a negative discharge electrode which is installed at the static eliminator body and has a singular or a plurality of pieces of negative discharge needles to form negative ions when a negative voltage is applied. So that there are more positive discharge needles than the negative discharge needles, and so that the positive ion amount of a piece of positive discharge needles is made less than the negative ion amount of a piece of negative discharge needles, by setting an absolute value of the positive voltage applied to the positive discharge electrode to be smaller than the absolute value of the negative voltage applied to the negative discharge electrode in advance, corona discharge is carried out. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a static eliminator that neutralizes and removes static electricity from an object by irradiating an electrostatically charged object with a large amount of positive and negative ions.

  Generally, a static eliminator generates ions by applying a high voltage generated by a high-voltage power supply to a discharge electrode for generating ions. Depending on the type of high voltage to be applied, the system is classified into an AC system, a DC system, and a pulsed DC system. For example, a DC type static eliminator generates positive / negative ions separately by generating positive / negative high voltages separately and applying them to discharge electrodes for generating ions.

However, when used for a long time, the positive / negative ion balance is deteriorated, and there is a problem that the efficiency of removing static electricity from the object is deteriorated.
Conventionally, this problem has been addressed as follows.

For example, in Patent Document 1, in a DC static eliminator in which a DC high voltage is applied to positive and negative discharge electrodes from positive and negative high voltage generation circuits to generate positive and negative ions, the positive discharge electrode side has a discharge current. The discharge current is detected by the detection resistor, and the positive high voltage generation circuit is feedback controlled so that the discharge current is constant. On the negative discharge electrode side, the ion current is detected by the ion detector, and the negative current is detected. The high voltage generation circuit is feedback-controlled so that positive and negative ion currents are balanced.
Thereby, in addition to achieving a highly accurate ion balance, it is possible to suppress a reduction in the charge removal performance. However, since a control circuit unit is required in addition to the positive and negative high voltage generation circuits, the number of circuit parts increases, the product becomes large, and the cost also increases.

In Patent Document 2, corona discharge is performed between the positive discharge needle and the negative discharge needle, and at the same time, corona discharge is performed between the positive discharge needle and the ground electrode and between the negative discharge needle and the ground electrode. If the ground electrode is formed into a pipe shape that can supply air, and a number of air injection holes are provided along the arrangement direction of the positive discharge needles and the negative discharge needles, positive and negative ions can be blown far away.
As a result, positive / negative ion balance can be achieved by a simple mechanical configuration instead of electrical ion balance control, and an increase in ion imbalance over time can be kept low even when used for a long time. However, providing a large number of air injection holes as a pipe that can supply air to the ground electrode requires a new and complicated mechanism, so this also increases the number of parts of the new mechanism and controls it. The part becomes larger.

Japanese Patent Laid-Open No. 2003-068497 JP 2001-035686 A

  However, it is examined whether the above problem can be solved without loading a new control circuit for generating positive / negative ions and a new mechanism.

  First, when the discharge electrode for generating ions is worn by discharge, the acute angle of the tip thereof becomes dull, and accordingly, ions are hardly generated. Here, it has been found that the discharge electrode for positive ions has a larger amount of wear than the discharge electrode for negative ions. Therefore, since the above-described DC type static eliminator has a structure in which ions are generated from the positive / negative individual discharge electrodes, when used for a long period of time, it is more positive for positive ions than for negative ion discharge electrodes. The amount of wear of the discharge electrode is large, and the amount of decrease of positive ions increases. As a result, there is a problem that the balance between positive / negative ions is deteriorated and the efficiency of removing static electricity from the object is deteriorated.

  However, although it is conceivable to select a material with low wear for the discharge electrode for generating ions, in reality, it is difficult to find an optimum material that is easy to process and meets the above-mentioned purpose.

  The problem to be solved by the present invention is to provide a static eliminator that balances positive / negative ions for a long period of time and prevents a reduction in static electricity removal efficiency of an object.

The invention according to claim 1 is a corona discharge type static eliminator using a DC voltage, and is provided in the static eliminator body and a plurality of positive discharges that are provided in the static eliminator body and generate positive ions when a positive voltage is applied. A positive discharge electrode having a needle, and a negative discharge electrode provided on the static eliminator body and having one or a plurality of negative discharge needles that generate negative ions when a negative voltage is applied to the positive discharge needle. The number of positive ions applied to the positive discharge electrode is set to be larger than the number of negative discharge needles and the amount of positive ions per positive discharge needle is smaller than the amount of negative ions of one negative discharge needle. Corona discharge is performed by setting the absolute value of the voltage to be smaller than the absolute value of the negative voltage applied to the negative discharge electrode in advance.
The static eliminator has a configuration in which the number of positive discharge needles is larger than the number of negative discharge needles, and the amount of positive ions generated is increased. However, a high voltage applied to the positive discharge needle is applied to the negative discharge needle. By making it smaller than the high voltage, the generation amount of both positive / negative ions is made the same. As a result, since the high voltage applied to the positive discharge needle is small, the wear amount of the positive discharge needle is reduced even when used for a long time, and the balance of the positive / negative ion generation amount can be maintained.

Further, according to a second aspect of the present invention, in the static eliminator according to the first aspect, the positive discharge needle or the negative discharge needle is formed with a plurality of protrusions on the plate electrode to which the high voltage is applied. It is characterized by.
As a result, a plurality of positive or negative discharge needles can be integrally formed by pressing or etching on the plate electrode, so that the quality of the discharge needles can be kept constant and the balance of the amount of ions generated can be maintained. It becomes.

Next, the invention according to claim 3 is the static eliminator according to claim 1 or 2, wherein the static eliminator has an air passage and an air passage opening that are provided in the static eliminator main body and eject the gas flow of the positive ions and the negative ions. Therefore, it is possible to diffuse ions to a space where ions are eliminated by a fan or compressor air.

  Finally, the invention according to claim 4 is the static eliminator according to claim 1 or 2, further comprising a positive electrode holder and a negative electrode holder for holding the positive discharge electrode and the negative discharge electrode, respectively. Since the positive discharge electrode and the negative discharge electrode are respectively connected by wire from the static eliminator body, and the corona discharge is performed by installing the positive electrode holder and the negative electrode holder in the vicinity of the space to be neutralized, Without using the blowing means, it is possible to remove the object using only the lines of electric force generated by the potential difference between the electrode and the object to be eliminated, that is, the flow of charges.

  According to the present invention, the number of positive discharge needles is greater than the number of negative discharge needles, and the high voltage applied to the positive discharge needles is smaller than the high voltage applied to the negative discharge needles. It becomes possible to maintain the balance of the positive / negative ion generation amount.

In the static eliminator comprising a plurality of positive discharge needles to which a positive DC high voltage is applied and one or a plurality of negative discharge needles to which a negative DC high voltage is applied, the number of the positive discharge needles is The best configuration is such that the number of high voltage applied to the positive discharge needle is larger than the number of negative discharge needles and is smaller than the high voltage applied to the negative discharge needle.

  FIG. 1 shows a first embodiment of the static eliminator of the present invention. The static eliminator 6 (here, since it is configured in the main body of the static eliminator has the same meaning) is composed of a high voltage generator 1 housing 6a, an ion generating air passage 6b and an ion outlet 6c. A positive high voltage is applied from 1 to the positive electrode generating discharge electrode 2a via the positive high voltage output line 5a, and corona discharge is generated by the discharge needles A, B and C at the tip of the electrode to generate positive ions. Let Similarly, for negative ions, a negative high voltage is applied from the high voltage generator 1 to the negative ion generating discharge electrode 2b via the negative high voltage output line 5b, and a corona discharge is generated by the discharge needle A at the tip of the electrode. To generate negative ions. The generated positive ions and negative ions are sent from the ion outlet 6c to the outside of the static eliminator 6 by using the air blown from the fan 7 to reduce static electricity of the object.

  The high voltage generator 1 used in the present invention boosts the input voltage applied between the + input lead wire 3 and the − input lead wire 4 with a piezoelectric transformer in the high voltage generator 1 to produce a positive high voltage. A positive high voltage is generated from the voltage output line 5a, and a negative high voltage is generated from the negative high voltage output line 5b.

Further, the high voltage generator 1 has an output voltage adjusting means, and the positive ion generating discharge electrode 2a and the negative ion generating discharge electrode 2b are in the range of +5 kV to +12 kV and −5 kV to −12 kV, respectively. The applied voltage can be varied, and the amount of positive / negative ions generated changes accordingly. In the first embodiment, the applied voltages to the positive ion generating discharge electrode 2a and the negative ion generating discharge electrode 2b are set to +7.4 kV and −8.0 kV, respectively, to thereby increase the generation amount of positive / negative ions. Same amount. Here, for the output voltage measurement, a high voltage probe HV-P30 manufactured by Iwatatsu Corporation was used.

Next, the fan 7 used in the static eliminator is a small fan having a size of 25 mm square and an air volume of about 0.04 m ³ / min.

  Further, a dust removal filter 8 of 25 mm square is installed at the air suction port of the air passage 6b for ion generation, and the mesh size of the filter 8 is 1.5 mm square and cannot pass through this mesh. Dust does not enter 6b.

  FIG. 2 shows a schematic diagram of a positive ion generating discharge electrode 2a used in the first embodiment, and FIG. 3 shows a negative ion generating discharge electrode 2b used in the first embodiment. The discharge electrodes 2a and 2b for generating ions are formed by processing a stainless steel plate having a thickness of 0.2 mm, and the discharge needles A, B, and C at the tip are sharpened so that the electric field is easily concentrated.

Generally, when the applied voltage is the same, if the number of discharge needles at the tip of the discharge electrode is increased, the amount of ions generated increases. Further, it is known that when the number of discharge needles is the same, the amount of generated ions increases as the applied voltage increases.

  In addition, when the positive / negative applied voltage is the same, the discharge needle of the discharge electrode 2a for generating positive ions has a greater amount of wear due to discharge when used for a longer time than the discharge needle of the discharge electrode 2b for generating negative ions. Many are known.

  FIG. 4 shows a conventional static eliminator. In this conventional example, the number of discharge needles of the positive ion generating discharge electrode 2a and the negative ion generating discharge electrode 2b is one, and the applied voltages to the main electrodes are the same as +8 kV and -8 kV.

  FIG. 5 is a graph showing the relationship between the number of positive discharge needles of Example 1 and the voltage applied to the positive discharge needles of the static eliminator of Example 1 and the conventional static eliminator. Here, with respect to the number of discharge needles of the first embodiment, the number of negative discharge needles of the discharge electrode 2b for negative ion generation is fixed to one as in the conventional example, and the positive number of discharge electrodes 2a for positive ion generation is positive. The number of discharge needles was changed to 2, 3, and 4. On the other hand, with respect to the voltage applied to the discharge electrode, the negative high voltage is not changed from the conventional example, but is fixed at −8 kV, and the positive high voltage is positive / negative for each number of positive discharge needles. The static elimination time was adjusted to be the same.

In addition, MODEL700A manufactured by Hugle Electronics Co., Ltd. is used as a charged plate monitor for measuring the static elimination time in this measurement, and positive charge static elimination time (time for reducing +5,000 V to +500 V), negative charge elimination time ( The time for reducing −5,000 V to −500 V) was measured. Here, the ions blown from the ion outlet 6c hit the center of the charged plate, and the distance between the ion outlet 6c and the charged plate monitor was set to 20 cm.

  As can be seen from FIG. 5, in the static eliminator of Example 1, the voltage applied to the positive ion generating electrode 2a is smaller than the +8.0 kV of the conventional static eliminator. In addition, it can be seen that as the number of positive discharge needles of the positive ion generating electrode 2a increases to 2, 3, and 4, the applied voltage decreases to +7.4 kV, +7.0 kV, and +6.7 kV. This is because the amount of wear after a long time per positive ion discharge electrode is larger than that of the negative ion discharge electrode, so that the amount of decrease in positive ions increases. Therefore, the positive / negative ion balance after a long time can be maintained by reducing the amount of positive ions generated by one discharge electrode for positive ions in advance. In the static eliminator of the first embodiment shown in FIG. 5, the number of positive discharge needles is set to 3, and the voltage applied to the positive ion generating electrode 2a is set to +7.0 kV.

Therefore, since the static eliminator of the first embodiment can set the applied voltage to the positive ion generating electrode 2a lower than that of the conventional static eliminator, the wear of the positive ion generating electrode 2a when used for a long period of time is reduced. Can be reduced. As a result, it is possible to maintain the balance of the positive / negative ion generation amount in the initial and long term.

  FIG. 6 shows a second embodiment of the static eliminator of the present invention. The static eliminator of the second embodiment is configured by forming the discharge needles of the positive ion generating electrode 2a and the negative ion generating electrode 2b of the static eliminator of the first embodiment with a stainless steel brush instead of a metal plate. As in Example 1, the number of discharge needles of the positive ion generating electrode 2a is larger than the number of discharge needles of the negative ion generating electrode 2b, and the same effect as in Example 1 can be obtained.

  FIG. 7 shows a third embodiment of the static eliminator of the present invention. Unlike the static eliminator of the first embodiment, the static eliminator of the third embodiment (comprising a static eliminator main body and positive and negative ion holders) does not have a blowing means such as the fan 7. Instead, both the positive high voltage output line 5a and the negative high voltage output line 5b from the high voltage generator 1 are made as long as about 3 m, and the positive ion generating electrode 2a and the negative ion generating electrode 2b are separately provided. The positive electrode generating discharge electrode holder 9a and the negative ion generating discharge electrode holder 9b are respectively installed.

  Here, the shape of the electrode holder is 15 mm × 20 mm × 30 mm, and the discharge electrode can be screwed. Moreover, it has a structure that prevents human fingers from entering through the air outlet.

Since the static eliminator of the third embodiment has the above-described structure, both the positive / negative electrodes can be installed in the vicinity of the space to be neutralized, and the target can be efficiently neutralized without a blowing means.

In addition, the static eliminator of the third embodiment is set to the number of positive discharge needles three and the applied voltage to the positive ion generating electrode 2a is +7.0 kV, similarly to the static eliminator of the first embodiment. The same effect as in Example 1 can be obtained.

  With the static eliminator of the present invention, it is possible to maintain a balance between positive / negative ion generation amounts due to wear of the ion generation electrode when used for a long period of time.

It is Example 1 of the static eliminator of this invention. It is the schematic of the discharge electrode 2a used for the present Example 1. FIG. It is the schematic of the discharge electrode 2b used for the present Example 1. FIG. This is a conventional static eliminator. 3 is a graph showing the relationship between the number of positive discharge needles of Example 1 and the voltage applied to the positive discharge needles. It is Example 2 of the static eliminator of this invention. It is Example 3 of the static eliminator of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... High voltage generator, 2a ... Discharge electrode for positive ion generation, 2b ... Discharge electrode for negative ion generation,
3 ... + input lead wire, 4 ...- input lead wire,
5a ... Positive high voltage output line, 5b ... Negative high voltage output line, 6 ... Static eliminator,
6a ... High voltage generator 1 housing, 6b ... Air path for ion generation, 6c ... Ion outlet,
DESCRIPTION OF SYMBOLS 7 ... Fan, 8 ... Dust removal filter, A, B, C ... Discharge needle 9a ... Discharge electrode holder for positive ion generation, 9b ... Discharge electrode holder for negative ion generation,
10a ... Positive ion outlet 10b ... Negative ion outlet

Claims (4)

  Corona discharge type static eliminator by DC voltage, a static eliminator body, a positive discharge electrode provided in the static eliminator body and having a plurality of positive discharge needles that generate positive ions when a positive voltage is applied; A negative discharge electrode having a single or a plurality of negative discharge needles that are provided in the static eliminator body and generate negative ions when a negative voltage is applied, and the number of positive discharge needles is greater than the number of negative discharge needles In addition, the absolute value of the positive voltage applied to the positive discharge electrode is set to the negative discharge so that the positive ion amount per positive discharge needle is smaller than the negative ion amount of one negative discharge needle. A static eliminator characterized in that corona discharge is set in advance smaller than the absolute value of a negative voltage applied to an electrode.   The static eliminator according to claim 1, wherein the positive discharge needle or the negative discharge needle has a plurality of protrusions formed on a plate electrode to which the high voltage is applied.   3. The static eliminator according to claim 1, further comprising an air passage and an air passage opening that are provided in the static eliminator main body and eject a gas flow of the positive ions and the negative ions. 4.   The static eliminator according to claim 1 or 2, further comprising a positive electrode holder and a negative electrode holder for respectively holding the positive discharge electrode and the negative discharge electrode, and the positive discharge electrode and the negative electrode holder from the static eliminator body, respectively. The discharge electrode is connected by wire, and the corona discharge is performed by installing the positive electrode holder and the negative electrode holder in the vicinity of the space to be neutralized.

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