JPH0512837B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a capacitively coupled charge eliminating electrode for eliminating or charging an object by applying an alternating current high voltage to an electrode needle.

[Conventional technology]

FIGS. 12 to 14 show conventional general static elimination electrodes using electrode needles. This static elimination electrode A
In this example, each electrode needle a is individually fixed to the outer surface of a conductive ring b, and the conductive ring b is fitted onto the outer periphery of a high voltage cable e whose core wire d is covered with an insulating material c. An insulating coating f is applied to the outer periphery of the joint part, and a conductive ring b is buried therein.The overall appearance is cylindrical, and a large number of electrode needles a are protruded in a line from the outer circumferential surface at predetermined intervals. It's taking shape. Usually, the static elimination electrode A is supported by a pair of holders g, and a ground electrode plate h is installed between these holders g.

[Problem to be solved by the invention]

However, this conventional static elimination electrode has the following problems. Since the number of parts and the number of assembly steps are large, the manufacturing process is laborious and time-consuming, and the cost is high.Since the conductive ring b is fitted to the outer periphery of the high-voltage cable e, the spacing between the electrode needles a and the length thereof are uneven. Due to its structure, mass production is not possible. The shape is limited to a cylinder. It cannot be downsized. There is little flexibility in specifications. In addition to the problems caused by the mechanical structure, the effective static elimination current is also small. The attenuation of the effective static elimination current is large when dust etc. adhere to the product. There was also a fundamental problem. To explain this point, the above-mentioned conventional structure can be represented by an equivalent circuit as shown in FIG. Here, the core wire d of the high-voltage cable e and the electrode needle a are capacitively coupled by the conductive ring b to form a capacitance Cp. An insulating coating f is applied to the outer periphery of the core wire d and the conductive ring b, but there is a capacitance Cg between the electrode needle a and the ground.
exists. In addition, the insulation coating f of this static elimination electrode A
There is an insulation resistance Rg1 between the insulating body covered all around and the ground, and an insulation resistance Rg2 between the electrode needle a and the ground.
exists respectively. These Cg, Rg1, and Rg2 have elements that reduce static elimination performance. That is, when this static elimination electrode is used for a long time, dust adheres to the insulating body. This dust deteriorates insulation resistance depending on the adhesion state and temperature.
This deterioration of insulation resistance can be expressed as Rg1 and Rg2. This deteriorated insulation resistance Rg1 is the same as when a conductive ring is further wrapped around the outer periphery of the insulation coating f, and between the electrode needle a and the conductive ring b used to obtain an integrated coupling capacitance. A capacitance Cg is formed. In this state, the impedance between the electrode needle a and the ground decreases due to the series impedance of Cg and Rg1 and the parallel impedance of Rg2, so the voltage Vp applied to the electrode needle a also decreases. Therefore, electrode needle a
If the high voltage Hv to be applied to is constant, the effective static elimination current will decrease. An object of the present invention is to provide a novel capacitively coupled charge eliminating electrode that can eliminate these conventional problems.

[Means to solve the problem]

The present invention not only has a large dielectric constant and is electrically stable, and can be easily reduced in size and weight as technology develops, it also has excellent mechanical strength, is easy to manufacture, and has recently become relatively inexpensive. Focusing on ceramic dielectric materials that have become available, we developed multiple electrode needles 6.
Each of these is individually implanted in a ceramic dielectric 4 in order to obtain a coupling capacity, and supported via each ceramic dielectric 4 on a common conductive plate 1 to which a high voltage is applied.

[Effect]

When a high voltage is applied to the conductive plate 1, a capacitance is generated by the ceramic dielectric 4 between it and the electrode needle 6, and a high voltage is induced in the electrode needle 6. The capacitance can be arbitrarily selected depending on the thickness of the conductive plate 1. The shapes of the conductive plate 1 and the ceramic dielectric 4 can be arbitrarily selected. FIG. 7 shows an equivalent circuit of the electrode structure according to the present invention. The conductive plate 1 and the electrode needles 6 are made of a ceramic dielectric plate 4.
are capacitively coupled to form an electrostatic capacitance Cp between them. Each electrode needle 6 is individually implanted in the ceramic dielectric 4 and surrounded by it. This means that the capacitance Cg and insulation resistance Rg1, which were problems in the conventional example described above, do not directly affect the electrode needle 6, but occur between the conductive plate 1 supporting the ceramic dielectric 4 and the ground. become. Therefore, only Rg2 generated when the insulation resistance deteriorates will affect the electrode needle 6.
There is less tendency for the effective static elimination current to decrease due to contamination.

【Example】

Embodiments of the present invention will be described in detail below with reference to the drawings. 1 and 2 show a charge eliminating electrode according to a first embodiment of the present invention. This charge-eliminating electrode has a horizontally long metal conductive plate 1 with a large number of circular mounting holes 2 formed in a line at regular intervals, and a short pipe-shaped ceramic dielectric body 4 with a circular flange 3 at one end. are fixed through the respective mounting holes 2, and the bases of electrode needles 6 are inserted into the shaft holes 5 of the ceramic dielectric 4, with their tips protruding from one end of the ceramic dielectric 4. The assembly consists of ceramic dielectric 4
This is done by inserting the electrode needle 6 into the shaft hole 5 in advance, and then inserting the ceramic dielectric 4 into the mounting hole 2 until the flange 3 abuts against the upper surface of the conductive plate 1. Therefore, a large number of electrode needles 6 are individually fixed on the conductive plate 1 at regular intervals through each ceramic dielectric 4, and when a high voltage is applied to the conductive plate 1, the ceramic dielectric Conductive plate 1 by body 4
Electrostatic capacitance is generated between the electrode needles 6 and the electrode needles 6, and a high voltage is induced in the electrode needles 6 all at once.For example, a bar-shaped ground electrode (not shown) is attached to the electrode needles 6 along the direction in which they are arranged. If they face each other, static electricity can be removed from the object by glow discharge or corona discharge. 3 and 4 show a second embodiment of the present invention, in which the conductive plate 1 is rectangular, and a large number of electrode needles 6 are individually implanted in the same ceramic dielectric material 4 as above.
They are arranged in multiple rows and fixed via ceramic derivatives 4. Therefore, if a plurality of ground electrodes 7 are arranged parallel to each other in the direction in which the electrode needles 6 are arranged,
By simply applying a high voltage to one conductive plate 1, static electricity can be removed from multiple rows at the same time. FIG. 5 shows a third embodiment, in which a conductive plate 1 is formed into a ring shape, and electrode needles 6 are fixed at regular intervals in the circumferential direction via a ceramic dielectric 4 in the same manner as described above. It can eliminate static electricity in a ring shape. In the fourth embodiment shown in FIG. 6, each electrode needle 6 is implanted in a plate-shaped ceramic dielectric material 4, and the ceramic dielectric material 4 is fixed on a conductive plate 1, so that a plurality of electrode needles 6 are fixed at a constant level. They are arranged and protruded on the conductive plate 1 with a ceramic dielectric 4 interposed therebetween at intervals of . In order to investigate the performance of the charge eliminating electrode according to the present invention,
The following experiments were conducted on the first embodiment shown in FIGS. 1 and 2 and the conventional example described above. <Measurement of effective static neutralization current>"Static electricity safety guidelines" (edited by the Industrial Safety Research Institute of the Ministry of Labor,
Using the measurement circuit shown in (published in 1978), a high DC voltage is applied to the simulated charged plate to charge it, and the distance between the simulated charged plate and the electrode needle is 5 cm, and a high voltage at a commercial frequency of 7KV is applied to the electrode needle. Then, the corona discharge current flowing through the simulated charged plate was measured. Note that the coupling capacitance in this case was 7.08 pF in the present invention and 7.13 pF in the conventional example. FIG. 8 shows the results of investigating the relationship between the voltage applied to the simulated charged plate and the corona discharge current in this experiment. Compared to the conventional example, the present invention has approximately
The effective static elimination current was 1.17 times higher, and about 1.31 times higher at +15KV. Furthermore, the effective neutralization current when charged at -5 KV was measured to be 0.21 μA/cm, which fully satisfies the standard value shown in the above-mentioned "Static Electricity Safety Guidelines". <Attenuation characteristics of effective static neutralization current> FIG. 9 shows the results of an experiment in which the attenuation characteristics of effective static neutralization current of the present invention and the conventional example were investigated. In this experiment, a high commercial frequency voltage of 8.5KV was applied to the electrode needle, and a corona discharge test was conducted continuously over a long period of time.A DC voltage of -5KV was applied to the simulated charged plate.
Measurements were made with the distance between the electrode needle and the simulated charged plate set at 50 mm. In the figure, HC and UC indicate ceramic dielectric materials. In the case of the present invention, compared to the conventional example,
The effective static elimination current after 2000 hours was approximately twice as high. <Measurement of ground short-circuit battery> Ten arbitrary electrode needles were selected from among the electrode needles, and the ground short-circuit current and the coupling capacity of the electrode needles were measured using the measurement circuit shown in FIG. The measurement results are shown in FIG. As can be seen from this figure, the ground short circuit current in the case of the present invention is 8 to 9 μA, which is about 1/2 lower than that in the conventional example.
In addition, the ground short-circuit current is 1/3 of the value shown in the "Structural Standards for Explosion-Proof Voltage Static Eliminator" in the "Static Electricity Safety Guidelines" above, reducing shock when the human body comes into contact with the electrode needle. Which indicates that. This is considered to be because, in the case of the present invention, each electrode needle is individually implanted in a ceramic dielectric material having an insulating function, so that each electrode needle has an independent structure.
It can also be seen that the coupling capacitance is stable despite the simple mounting structure in which the ceramic dielectric is fitted into the holes of the conductive plate.

【Effect of the invention】

In the present invention, each of the plurality of electrode needles is individually implanted in a ceramic dielectric material having a large relative dielectric constant, and is supported on a common conductive plate through each ceramic dielectric material, so that the following effects can be obtained. . The effective static elimination current is large and the static elimination performance is high. Even if dust adheres, the attenuation of the effective static elimination current is small, and static elimination performance can be maintained. It is much easier to manufacture than conventional methods, can be provided at a lower cost, and improves the quality of the product. Mass production is possible because the number of parts and assembly man-hours are small. Easy to downsize. You can freely choose the shape, specifications, etc. The spacing between electrode needles can be kept constant. By changing the thickness of the metal plate, the capacitance between the metal plate and the electrode needle can be adjusted, so static electricity can be removed or charged under optimal conditions. The electrode structure can be subdivided. Higher safety than before.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the first embodiment of the present invention, FIG. 2 is a perspective view of the same, FIG. 3 is a perspective view of the second embodiment, and FIG.
5 is a plan view of the third embodiment, FIG. 6 is a perspective view of the fourth embodiment, and FIG. 7 is an equivalent circuit diagram of the electrode according to the present invention. Furthermore, Fig. 8 is a line graph showing the measurement results of the effective static elimination current carried out to compare the present invention and the conventional example, Fig. 9 is a line graph showing the attenuation characteristics of the effective static neutralization current, and Fig. 10 is a line graph showing the attenuation characteristics of the effective static neutralization current. Schematic diagram of a measurement circuit that measures current, No. 11
The figure is a comparison diagram with the conventional example showing the measurement results. 12 to 15 show conventional examples,
FIG. 12 is a front view, FIG. 13 is a sectional view, FIG. 14 is a front view of a portion of the interior, and FIG. 15 is an equivalent circuit diagram thereof. 1... Metal plate, 4... Ceramic dielectric, 6...
...electrode needle.

Claims (1)

[Claims] 1. Each of the plurality of electrode needles is individually implanted in a ceramic dielectric material in order to obtain coupling capacity, and is supported via each ceramic dielectric material on a common conductive plate to which a high voltage is applied. Capacitively coupled static electricity removal electrode.