JP2001035686A - Dc static eliminator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a DC static eliminator offering mechanically simplified construction, not for electric ion balance control purpose, permitting +/- ion balance and restricting the increase of ion unbalance with time in long-time use. SOLUTION: Corona discharge is generated between a plus discharge needle 4 and a minus discharge needle 5 and corona discharge is also generated at the same time between the plus discharge needle 4 and each of earth electrodes 6, 7 and between the minus discharge needle 5 and each of the earth electrodes 6, 7. The earth electrodes 6, 7 are formed in pipe shape capable of supplying air, to which a number of air nozzles are added along the arrangement of the plus discharge needle 4 and the minus discharge needle 5 to allow +/- ions to fly far away.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct current eliminator for applying positive and negative DC high voltages to positive and negative discharge needles to generate positive and negative ions to eliminate a charged material. .

[0002]

2. Description of the Related Art As a direct current static eliminator of this type, as described in Japanese Patent Application Laid-Open No. 5-299191, a positive electrode lead and a negative electrode lead are provided on a rod-like or long-plate-like insulating holder. And wire them side by side,
A plurality of discharge needles are alternately connected to the positive electrode lead and the negative electrode lead via current limiting resistors and positive and negative, respectively, and one end of the positive electrode lead and the negative electrode lead are connected to the positive and negative terminals of the DC high voltage generator. We already have one connected to the negative output.

In this conventional DC static eliminator, positive and negative voltage doubler rectifier circuits are used for the DC high voltage generator, and the number of stages of the negative side voltage doubler rectifier circuit is made smaller than that of the positive side voltage doubler rectifier circuit. The balance of plus and minus ions.

[0004] The DC neutralization system having such a structure has an excellent ability to generate positive and negative ions and an excellent ability to neutralize a charged material. However, the DC neutralization system has a negative side voltage doubler and a positive side voltage doubler. Even if an attempt is made to electrically balance ions due to the difference in the number of stages, if used for a long period of time, the amount of positive and negative ions generated by dust attached to the positive and negative discharge needles will be unbalanced, and the imbalance will elapse over time With the increase, the charged material may be charged in reverse.

On the other hand, Japanese Patent Application Laid-Open No. 8-321394 discloses that in order to achieve a positive / negative ion balance in an AC static eliminator, a discharge electrode to which a positive / negative AC high voltage is applied from an AC power supply is grounded. The electrodes are opposed to each other with a gap, and the test plate is opposed to non-contact. When the test plate becomes corroded by corona discharge between the discharge electrode and the ground electrode, it flows from the ground to the test plate. A technology that measures the current with a DC ammeter and operates the variable resistor of the ion balance adjustment unit according to the measured current value to adjust the level of the negative component of the AC high voltage applied to the discharge electrode It has been disclosed.

Conventionally, as described above, when the same applied voltage is used for plus and minus, the amount of generated negative ions is larger than that of positive ions. Therefore, in the case of the DC neutralizer and the case of the AC neutralizer, However, the ion balance is intended to be achieved by making the negative applied voltage lower than the positive applied voltage.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is not to control the ion balance electrically but to achieve a positive / negative ion balance by a simple mechanical structure, and to imbalance the ions even after long use. An object of the present invention is to provide a direct current static eliminator capable of suppressing an increase due to aging over time.

Although the present invention employs a mechanical ion balance system, the present invention does not refuse the electric ion balance control system. By using it together, the ion balance accuracy can be further improved. .

[0009]

According to the present invention, a plurality of positive discharge needles to which a positive DC high voltage is applied and a plurality of negative discharge needles to which a negative DC high voltage is applied are provided with a corona between them. Ground electrodes extending in the arrangement direction of the plus discharge needles and the minus discharge needles are alternately arranged on the insulating holder at intervals where discharge can occur, and corona discharge can be generated with respect to these plus and minus discharge needles. It is characterized by being held in an insulating holder at intervals.

As described above, when corona discharge is caused between the positive discharge needle and the minus discharge needle, corona discharge is also caused between the plus discharge needle and the ground electrode and between the minus discharge needle and the ground electrode. The amount of positive and negative ions is generally smaller for both plus and minus than when there is no ground electrode.However, even if the plus and minus discharge needles become dirty and the amount of ion generation becomes unbalanced, plus and minus Can be kept low.

In a preferred embodiment, the positive discharge needles and the negative discharge needles are alternately arranged in a line, and the ground electrodes are fixed to the insulating holder on both sides in parallel with the arrangement.

Further, the ground electrode is formed in a pipe shape capable of supplying air, and a large number of air injection holes are provided in the pipe along the arrangement direction of the positive discharge needles and the negative discharge needles.

[0013]

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIGS. 1 to 3 show a DC static eliminator according to a first embodiment of the present invention. In this DC static eliminator, an elongated printed board 2 is resin-coated in a rod-shaped insulating holder 1 having a U-shaped cross section.
A plurality of positive discharge needles 4 and a plurality of negative discharge needles 5 buried in the printed circuit board 3 at predetermined intervals alternately plus and minus are arranged in a line in the insulating holder 1. And the ground electrodes 6 and 7 are fixed to both sides of the insulating holder 1 in parallel with the arrangement of the discharge needles 4 and 5.

As shown in FIG. 3, a positive electrode lead 8 and a negative electrode lead 9 are printed on the surface of the printed circuit board 2 in parallel along both side edges thereof. Also, on the printed circuit board 2, a large number of conductive bushes 10 are implanted in a line at regular intervals on the center line between the two electrode leads 8,9. The opening of each conductive bush 10 faces the surface of the printed circuit board 2.

The conductive bushes 10 implanted in a row in this manner include a positive electrode lead 8 and a negative electrode lead 9.
Are alternately connected via a current limiting resistor 11 and in an order of arrangement. That is, the connection destinations of the odd-numbered conductive bushes 10 in the arrangement order are alternately changed to the positive electrode leads 9 and the even-numbered conductive bushes 10 are alternately changed to the negative electrode leads 9, one at each planting location. They are individually connected via current limiting resistors 11.

Then, the positive and negative discharge needles 4.5
Is connected to the positive electrode lead 8 and the negative electrode lead 9 via the current limiting resistor 11 and in accordance with the arrangement order by inserting a part into the conductive bush 10 in an alternately positive and negative arrangement.・ Minus is connected alternately. The positive discharge needles 4 and the negative discharge needles 5 are arranged at an interval at which corona discharge occurs between them.

The printed circuit board 2 having such a structure and embedded in the resin 3 has a positive / negative power cable in which the positive electrode lead 8 and the negative electrode lead 9 are pulled out from the end block 12 at one end of the insulating holder 1. 1
3 and 14 respectively. Then, a positive high voltage is applied to the positive discharge needle 4 and a negative high voltage is applied to the negative discharge needle 5 from a DC high voltage power supply (not shown) through the power cables 13 and 14. .

The positive and negative discharge needles 4 and 5 are arranged along the center line of the insulating holder 1, but are parallel to the arrangement and are provided on both sides with ground electrodes 6 which are conductive plates having an L-shaped cross section.・ 7 are arranged. Ground electrodes 6 and 7 on both sides
Are fixed to the end blocks 12 at both ends of the insulating holder 1 at regular intervals so as to face the plus and minus discharge needles 4 and 5 at the same interval. Corona discharge occurs between the electrodes 6 and 7 and between the minus discharge needle 5 and the ground electrodes 6 and 7 on both sides.

In such a DC eliminator,
When the negative power cables 13 and 14 are connected to a DC high-voltage power supply and a positive DC high voltage is applied to the positive discharge needle 4 and a negative DC high voltage is applied to the negative discharge needle 5 at the same time, the positive and negative discharge needles 4 5 and the corona discharge occurs between the positive discharge needle 4 and the ground electrodes 6 on both sides.
7 and between the negative discharge needle 5 and the ground electrodes 6 on both sides
• Corona discharges are also generated between them and 7. As a result, the amount of plus and minus ions generated is reduced as compared with the case where the ground electrodes 6 and 7 are not provided.

As shown in FIG. 4, the inventor of the present invention has applied a charging plate 1 to which a voltage has been applied and charged as an object to be neutralized.
7, the positive DC high voltage applied to the positive discharge needle 4 is fixed, and the negative DC high voltage applied to the negative discharge needle 5 is made variable. An experiment was conducted to measure the degree of static elimination by measuring the above. Charge plate 17 and plus / minus discharge needles 4
The distance to 5 was 100 mm.

The positive DC high voltage applied to the positive discharge needle 4 is set to +5.86 kV, and the negative DC high voltage applied to the negative discharge needle 5 is set to -5.00 kV.
7, the potential of the charging plate 17 and the ionic current flowing between the positive and negative discharge needles 4 and 5 were measured, and the measured values were measured for those with the ground electrodes 6 and 7 (the present invention) and those without the ground electrodes 6. As a result of the measurement, a result as shown in the graph of FIG. 5 was obtained.

From FIG. 5, it can be seen that the one having the ground electrodes 6 and 7 has about 60% less ion current than the one without the ground electrodes 6, and the addition of the ground electrodes 6 and 7 reduces the generation of ion quantity. .

However, the ion balance was improved as shown in FIG. FIG. 6 shows that the negative DC high voltage applied to the negative discharge needle 5 in the equivalent circuit of FIG. 4 is varied from -3.0 kV to -7.0 kV. At this time, the voltage is induced on the charging plate 17 by ion imbalance. Is measured by the electrostatic voltmeter 18.

From FIG. 6, when there is no ground electrode 6,7, when the voltage applied to the minus discharge needle 5 is -3.0 kV, the charging potential of the charging plate 17 becomes about +1200 V, and the applied voltage becomes -7. At 0 kV, the charging potential is about-
When the voltage becomes 1200 V and the applied voltage is -5.0 kV, it is understood that the charged potential is zero volt and the ion balance is maintained.

On the other hand, when the ground electrodes 6 and 7 are provided, when the voltage applied to the minus discharge needle 5 is -3.0 kV, the charging potential of the charging plate 17 is as low as about +250 V, and the applied voltage is -7. Even at 0 kV, the charging potential is about -2.
When the applied voltage is as low as 00 V and the applied voltage is −5.0 kV, the charging potential is zero volt, and it is understood that the ion balance is maintained.

From these results, when the ground electrodes 6 and 7 are provided, the voltage applied to the minus discharge needle 5 is -3.0 k
Even if the voltage changes from V to -7.0 kV, the voltage induced on the charging plate 17 can be suppressed from about +250 V to about -200 V. This means that even if the positive and negative discharge needles 4 and 5 become dirty and the amount of ion generation becomes unbalanced, the deviation of the amount of positive and negative ion generation can be suppressed by providing the ground electrode. It is shown that.

Next, a second embodiment shown in FIGS. In the second embodiment, the ground electrodes 6 and 7 on both sides are formed in a pipe shape, and
A large number of air injection holes 19 are connected to the positive and negative discharge needles 4.
5 are provided at predetermined intervals in the arrangement direction, and an air supply port 20 is provided at one end of each of the pipe-shaped ground electrodes 6 and 7 so that air can be supplied through an air hose 21. The direction of air injection from the air injection hole 19 is
The direction is the same as the direction of the positive and negative discharge needles 4 and 5.

When air is jetted from the many air jet holes 19 of the ground electrodes 6 and 7 in this manner, the plus and minus ions generated by the corona discharge as described above can be made to fly far away.

[0030]

As described above, according to the present invention, corona discharge is caused between the plus discharge needle and the minus discharge needle, and at the same time, between the plus discharge needle and the ground electrode, and between the minus discharge needle and the ground electrode. Since corona discharge occurs between
The amount of plus and minus ions generated is generally smaller for both plus and minus than when there is no ground electrode, but even if the plus and minus discharge needles become dirty and the amount of ions generated becomes unbalanced, plus and minus Since the deviation of the negative ion generation amount can be suppressed low, the ion balance state can be stably maintained.

If the ground electrode is formed in a pipe shape that can supply air, and a number of air injection holes are provided along the arrangement direction of the positive discharge needle and the negative discharge needle, positive and negative ions can be made to fly far away to remove static electricity. Can be improved.

[Brief description of the drawings]

FIG. 1 is a partially omitted perspective view of a first embodiment of the present invention.

FIG. 2 is a sectional view of the same.

FIG. 3 is a perspective view of a part of a printed circuit board according to the first embodiment.

FIG. 4 is an equivalent circuit diagram of a measurement method in which a charge plate is discharged and tested.

FIG. 5 is a graph showing a relationship between a case where a ground electrode is provided and a case where no ground electrode is provided, by measuring a relationship between a potential of a charging plate and an ion current between positive and negative discharge needles.

FIG. 6 shows a case where a negative DC high voltage applied to a negative discharge needle is varied, and a potential induced on a charging plate is measured by ion imbalance at this time, and a ground electrode is provided and a ground electrode is not provided. It is the graph which compared with FIG.

FIG. 7 is a partially omitted perspective view of a second embodiment of the present invention.

FIG. 8 is a plan view of the same.

FIG. 9 is a side view of the same.

FIG. 10 is a sectional view of the same.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulated holder 2 Printed circuit board 3 Resin 4 Positive discharge needle 5 Negative discharge needle 6.7 Ground electrode 8 Positive electrode lead 9 Negative electrode lead 10 Conductive bush 11 Current limiting resistor 12 End block 13.14 Power cable 17 Charging plate 18 Electrostatic potentiometer 19 Air injection hole 20 Air supply port 21 Air hose

Claims (3)

[Claims] 1. A plurality of positive discharge needles to which a positive DC high voltage is applied and a plurality of negative discharge needles to which a negative DC high voltage is applied are set to have an interval at which corona discharge can occur. While alternately arranging on the insulating holder,
A direct current static eliminator characterized in that a ground electrode extending in the arrangement direction of the positive discharge needle and the negative discharge needle is held in an insulating holder at an interval at which corona discharge can be generated with respect to the positive discharge needle and the negative discharge needle. 2. The method according to claim 1, wherein the positive discharge needles and the negative discharge needles are alternately arranged in a line, and the ground electrodes are fixed to the insulating holder on both sides in parallel with the arrangement.
2. The direct-current static eliminator according to 1. 3. The ground electrode according to claim 1, wherein a plurality of air injection holes are provided along a direction in which the positive discharge needles and the negative discharge needles are arranged. DC eliminator.