JPH07120560B2 - Static elimination electrode - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a static elimination electrode for generating ions by corona discharge to neutralize a charged object.

[0002]

2. Description of the Related Art FIG. 9 to FIG. 11 show a conventional general capacitive coupling type static elimination electrode. In this static elimination electrode, electrode needles a are individually fixed to the outer surface of the conductive ring b, and the conductive ring b is provided at a constant interval on the outer circumference of the high voltage cable e in which the core wire d is covered with an insulating material c. After fitting with, the insulating ring f is applied to the outer periphery of the fitting portion to embed the conductive ring b,
The embedded cylindrical body is supported by a pair of holders g, and two plate-like or rod-like (plate-like in the figure) ground electrodes h are installed between the holders g on both sides of the electrode needle a. It is a thing.

[0003]

However, this conventional static elimination electrode has the following problems because the ground electrode h is plate-shaped or rod-shaped. The corona discharge is unstable and there is a drawback that uneven charge removal occurs. Since the static elimination current (corona current) is smaller than the applied voltage, a high applied voltage is required to increase the static elimination current and improve the static elimination effect, and the risk of ignition is accordingly high. Comparing the capacitively coupled type and the resistively coupled type, the corona current is significantly higher in the resistively coupled type than in the capacitively coupled type even with the same applied voltage. Had to connect.

An object of the present invention is to eliminate such problems of the prior art, that is, to perform stable charge removal that does not become a flammable ignition source even if the charging potential is high, and to perform large charge removal even with a low applied voltage. Not only is it safe to obtain a current, but self-discharge can be induced from the ground electrode to increase the amount of generated ions, so even if the applied voltage is low, the static elimination performance can be dramatically improved compared to the conventional one. An object of the present invention is to easily provide a stable product as a resistance coupling type static elimination electrode.

[0005]

The present invention SUMMARY OF], in neutralizing electrode which a plurality of discharge electrode needles arranged at regular intervals, as the electric discharger, and sintering a mixture of carbon or the like electrically conductive ceramic Using an electrode needle with a predetermined resistance value,
Further, the ground electrode needles are arranged opposite to each other on both sides of each discharge electrode needle.

[0006]

Since the ground electrode is also a needle like the discharge electrode, the directivity of discharge between these electrodes is constant, and stable corona discharge can be obtained. Since the ground electrode is a needle, its small
Electric field (line of electric force) from a charged object easily closes at the tip
The electric field strength at the tip of the ground electrode increases,
Self-discharge is induced from the tip, and the ground electrode has a needle-shaped tip.
If the edge is small, the electric field from the charged object will
Also becomes easier to close, and self-discharge from the discharge electrode side occurs.
Get better Therefore, the error caused by such self-discharge is
When turned on, the static elimination performance can be improved. Electric discharger, since conductivity ceramic by sintering a mixture of carbon or the like in which remembering a predetermined resistance value, it is possible to suppress current
It is very easy to manufacture as a resistance coupling type static eliminator electrode and it can be provided at low cost, and the product quality can be stabilized.
In addition, the distance between the electrode needles can be made small, and since the structure is electrically stable and highly reliable, ignitable discharge can be suppressed.

[0007]

EXAMPLES Examples of the present invention will be described below. In FIG. 1 and FIG. 2, this static elimination electrode has a horizontal casing 1 made of plastic as an insulating holder, and a large number of discharge electrode needles 3 are planted on the bottom portion 2 of the casing 1 at regular intervals along the center line. Ground electrode needles 5 and 6 are similarly implanted at regular intervals on both sides of the discharge electrode needle 3.
The lower ends of these electrode needles 3, 4, 5 project from the outer bottom surface of the casing 1. The ground electrode needles 4 and 5 are arranged so as to be paired with the respective discharge electrode needles 3, one on each side of the ground electrode needles 3 and 5 facing each other at equal intervals.

The discharge electrode needle 3 is obtained by mixing a conductive ceramic such as SiC with an appropriate amount of carbon or the like in accordance with a designed resistance value, sintering the mixture into a thin rod shape, and sharply polishing the tip, and as a whole, it has a predetermined size. Has a resistance value. In this example, the ground electrode needles 4, 5
Is just metal.

A long convex portion 6 is formed on the inner bottom surface of the casing 1 along the center line. The discharge electrode needle 3 penetrates through the convex portion 6 and the high-voltage cable 7 installed on the convex portion 6.
Is connected to the conductor 8. The upper ends of the ground electrode needles 4 and 5 project into the casing 1 and are connected to the conductor 10 of the ground wire 9. The casing 1 is filled with an insulating mold 11, and the upper ends of the electrode needles 3, 4, 5 and the conductors 8, 11 are embedded in the insulating mold 11.

To use this static elimination electrode, a positive or negative high voltage is applied to all discharge electrode needles 3 via a high voltage cable 7, and all ground electrode needles 4 and 5 are grounded via a ground wire 9. To do. Since each discharge electrode needle 3 is a conductive ceramic having a predetermined resistance value, it is individually resistance-coupled to the conductor 8 of the high voltage cable 7 by its own resistance R as shown in the conceptual diagram of FIG. Has been done.
The ground electrode needles 4 and 5 on both sides of the discharge electrode needle 3 face each other at equal intervals, and since both the discharge electrode and the ground electrodes on both sides are needles, the discharge electrode needle 3 and A stable corona discharge is generated for each set between the ground electrode needles 4 and 5 on both sides.

The present inventors conducted the following experiment in order to confirm the effect of the present invention. FIG. 5 is a model diagram thereof, in which a metal flat plate 11 is opposed to the electrode needles 3, 4, and 5 with a gap G from the tip thereof, and a DC high voltage V is applied to the metal flat plate 11 to form a simulated charged object. While the AC high voltage Vd was applied to the needle 3 from the AC high voltage power supply 12 to generate the corona discharge, the static elimination current 1 flowing through the metal flat plate 11 was measured by the ammeter 13. In FIG. 6, the distance L between the discharge electrode needle 3 and the ground electrode needles 4 and 5 is 5 mm, and the applied AC high voltage Vd is 5 mm.
KV, the gap G is set to 1 cm, and the resistance value R is 100 MΩ when the discharge electrode needle 3 is resistively coupled as in the present embodiment.
200 MΩ, 300 MΩ, and electrostatic capacitance C in the case of capacitive coupling as shown in FIG. 4 is 6.4 pF, 9.0 pF, 1
5 is a graph showing the relationship between the negative charging potential V (KV) and the static elimination current I (μA) in each case with a stepwise change to 5.5 pF.

For comparison with the present invention, FIG. 7 is a model diagram in the case of conducting an experiment with only the discharge electrode needle 3 without the ground electrode needles 4 and 5. In the experiment of FIG. 7, the applied AC high voltage Vd and the interval G are 5 KV and 1 cm, which are the same as those described above, and the resistance value R is 200 M when the discharge electrode needle 3 is resistively coupled.
Ω, 350 MΩ, and capacitance C when capacitively coupled
Is gradually changed to 9.0 pF and 15.5 pF, and the negative charging potential V (KV) and the static elimination current I in each case are changed.
It is a graph showing the relationship of (μA).

As can be seen by comparing FIGS. 6 and 8,
In the case of the present invention, it was found that the degree of increase in the static elimination current I, which increases as the charging potential V increases, is extremely high.
This is because stable corona discharge can be obtained between the discharge electrode needle 3 and the ground electrode needles 4 and 5, and when the charging potential V becomes high, self-discharge occurs between the ground electrode needles 4 and 5 and the charged object. It is considered that the main factor is the generation of ions and the generation of ions due to the discharge. Further, when the discharge electrode needle 3 itself has a predetermined resistance value and is of the resistance coupling type as shown in FIG. 3, the stability becomes higher as the charging potential becomes higher than that of the capacitive coupling type as shown in FIG. It was also found to be advantageous in.

Further, although the experimental data are not shown concretely, in the case of the present invention, the degree of change of the static elimination current I with respect to the change of the interval G is large, and the AC high voltage V to be applied.
It was also found that the degree of change in the static elimination current I was large with respect to the change in d.

[0015]

As described above, the present invention has the following effects. Since the ground electrode is also a needle like the discharge electrode, the directivity of discharge between these electrodes is constant, and corona discharge occurs even at a low applied voltage, so stable static charge removal that does not become a flammable ignition source can be performed. . Even if the voltage application to the discharge electrode needle is interrupted, if the potential of the charged object is high, self-discharge occurs between the charged object and the ground electrode needle, and the charge is removed, which is safe. As electric discharger, since conductivity ceramic by sintering a mixture of carbon or the like was used as salicylic a predetermined resistance value, together with its production can be provided very easily and inexpensively as neutralizing electrode of the resistance linked In addition to stabilizing the product quality and making the distance between the electrode needles tighter, it is also possible to perform electrically stable and reliable static charge removal even when the charge potential of the static charge target is high. It is suitable as an explosion-proof electrode that can be suppressed.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a static elimination electrode according to an embodiment of the present invention.

FIG. 2 is a horizontal sectional view of the static elimination electrode.

FIG. 3 is a conceptual diagram of the above.

FIG. 4 is a conceptual diagram of a reference example of a capacitive coupling type.

FIG. 5 is a model diagram of an experimental example of the static elimination electrode according to the present invention.

FIG. 6 is a graph showing the experimental results of the above.

FIG. 7 is a model diagram of an experimental example using only a discharge electrode needle without a ground electrode needle.

FIG. 8 is a graph showing the experimental results of the above.

FIG. 9 is a side view of a conventional example.

FIG. 10 is a sectional view of the conventional example.

FIG. 11 is a side member showing the relationship between the high-voltage cable and the discharge electrode needle in the conventional example.

[Explanation of symbols]

 1 Casing (insulation holder) 3 Discharge electrode needle 4 Ground electrode needle 5 Ground electrode needle

Claims (1)

[Claims] 1. A static elimination electrode in which a plurality of discharge electrode needles are arranged at regular intervals, wherein each discharge electrode needle mixes carbon or the like with a conductive ceramic and sinters them to give a predetermined charge. A static eliminator having a resistance value, and ground electrode needles arranged on opposite sides of each discharge electrode needle, respectively.