JP2001110590A - DC static eliminator - Google Patents

Abstract

(57) [Summary] [Problem] Even if the corona discharge current of one of the positive and negative polarities decreases, it does not affect the other polarity, and it is difficult for dust and the like to adhere to the discharge needle. Both provide a DC neutralizer capable of maintaining stable discharge for a long time. SOLUTION: A plus side discharge needle 5 and a minus side discharge needle 5 are provided.
The ground electrodes 12a and 12b are opposed to each other at an interval shorter than the distance between the plus and minus discharge needles. The ground electrodes 12a and 12b are formed in a plate shape and are opposed to each other in parallel. The ground electrode may be formed in a ring shape, and plus and minus discharge needles may be arranged at the center of the ring.

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 a positive or negative DC high voltage to positive or negative discharge needles to generate positive or negative ions and to neutralize a charged object. .

[0002]

2. Description of the Related Art As a direct current static eliminator of this type, as disclosed in JP-A-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 a current limiting resistor and positive and negative, and one end of the positive electrode lead and one end of 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.

In a DC static eliminator having such a structure, corona discharge is generated between positive and negative discharge needles to generate positive and negative ions at the same time to eliminate static electricity. In the case of static elimination, a strong electric field is generated between the positive and negative discharge needles and the charged object, so that it is possible to generate an amount of positive and negative ions necessary for static elimination of the charged object.

FIG. 1 is a schematic view of an experimental example, in which a DC voltage is applied to a charging plate 50 by a DC high-voltage power supply 51 to charge it positively or negatively. the discharge needle 5 of the static eliminator 52
3, the charging potential of the charging plate 50 and the effective discharging current are measured while applying a high DC or AC voltage to the charging plate 50 to eliminate the charge.

FIG. 2 shows the results of such an experiment performed on a conventional DC neutralizer and a general AC neutralizer having the above-described structure. The relationship between the charging potential of the charging plate 50 and the effective neutralizing current is shown in FIG. , Plus ions and minus ions.

As can be seen from FIG. 2, when the static eliminator 52 is close to the charging plate 50, the discharge needle 53 of the static eliminator 52 is discharged under the influence of the electric field due to the static electricity of the charging plate 50. Since a neutralization current corresponding to the charging potential flows, ions necessary for neutralizing the charging plate 50 are generated by the neutralizer 52.

[0008]

However, when a static eliminator is installed at a position far away from the charged object and the charged object is slowly discharged, as shown in FIG. The discharge needle is not affected by the electric field due to the static electricity of the charged object. Therefore, in this case, the corona discharge is generated only by the electric field between the plus and minus discharge needles due to the plus and minus DC high voltage, and the amount of plus and minus ions generated is the difference between the plus and minus discharge needles. It depends only on the electric field between them.

In the case of such static elimination, positive and negative DC high voltages are simultaneously applied to the positive and negative discharge needles, and the direction of the field lines of the electric field is always negative from the tip of the positive side discharge needle. Since the discharge needle is directed toward the tip of the side discharge needle, the discharge mechanism becomes a discharge mechanism in which dust or the like easily adheres to the discharge needle. If dust or the like adheres to one of the discharge needles and becomes contaminated, the corona discharge current decreases in both positive and negative directions. In FIG. 3, when there is no charged object, the positive corona discharge current + I and the negative corona discharge current -I always have the same value.

[0010] Once dust or the like adheres to the discharge needle and becomes contaminated, the corona discharge current rapidly decreases and thereafter attenuates to the minimum limit value required for static elimination in a short time. FIG. 4 (A)
And (B) show a negative discharge current characteristic (the aging time is on the horizontal axis and the discharge current is on the vertical axis). If there is no ground electrode for each of the plus and minus discharge needles, Once dust or the like adhered to one of the negative discharge needles, the positive and negative discharge currents rapidly decreased, and attenuated to 1 μm or less in about 400 hours.

An object of the present invention is to solve such a problem, and even if the corona discharge current of one of the positive and negative polarities decreases, it does not affect the other polarity, and the discharge needle has dust or the like. It is an object of the present invention to provide a DC neutralizer capable of maintaining stable discharge for a long time in both positive and negative directions, without being easily adhered.

[0012]

SUMMARY OF THE INVENTION The present invention provides an insulated electrode holder in which a positive discharge needle to which a positive DC high voltage is applied and a negative discharge needle to which a negative DC high voltage is applied are separated from each other. In the DC static eliminator protruding in, for each of the plus side discharge needle and the minus side discharge needle,
It is characterized in that ground electrodes are opposed to each other at intervals shorter than the distance between the plus and minus discharge needles.

With this arrangement, an electric field is generated between the positive and negative discharge needles, and at the same time, an electric field is generated between the positive and negative discharge needles and the respective ground electrodes. Since the distance between the ground electrode and the ground electrode is shorter, the electric field between the discharge needle and the ground electrode becomes stronger, and corona discharge mainly occurs between the discharge needle and the ground electrode.

As a result, even if the discharge current of one of the plus and minus discharge needles is reduced due to the adhesion of dust or the like, it hardly affects the discharge needle of the other pole. Also,
Even if dust and the like adhere to the discharge needle, the attached dust and the like are scattered due to the strong electric field between the discharge needle and the ground electrode.

In the discharge current characteristics shown in FIG. 4, when the ground electrode is not provided, the voltage is attenuated to 1 μm or less in about 400 hours as described above. If 1000 hours were required and 1 μm was taken as the limit value for static elimination, static elimination was possible about 2.5 times longer than the case without the ground electrode. Therefore, the interval for cleaning the discharge needles is also about 2.5 times longer.

If the ground electrode is provided, the corona discharge is also stabilized, so that the ion current can be generated at a high value as shown in the ion current characteristics of FIGS. 5 (A) and 5 (B). In this case, since the ion current is measured by setting the distance between the plus and minus discharge needles and the charged object at 100 mm, the plus and minus discharge needles are affected by the strong electric field of the charged object. It is in a state where it is. Therefore, although the characteristics are different from those of the corona discharge current, the ion current is larger both when plus and minus when there is no ground electrode than when there is no ground electrode.

The ground electrode may be in the form of a plate, and a pair of positive and negative discharge needles may be arranged in parallel on opposite sides thereof, or a pair of ground electrodes may be formed in a ring shape, and the positive and negative discharge needles may be formed at the center of the ring. Place each needle.

The height of the ground electrode is preferably higher than the heights of the positive and negative discharge needles in consideration of safety.

When the insulated electrode holder is formed in a ring shape so that it can be attached to the outlet of the fan, the plus side discharge needle and the minus side discharge needle protrude from the inner peripheral surface thereof, and the inner peripheral surface is grounded. Hold the electrode.

[0020]

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

FIG. 6 shows a fan-attached DC static eliminator which is used by being attached to a blow-off portion of a fan. This DC static eliminator A is composed of a circular ring-shaped insulating electrode holder 1 as a main body and four portions thereof. And a single-piece structure in which a discharge electrode portion 2 is provided. On the outer periphery of the electrode holder 1, a plate-shaped mounting flange portion 3, which forms a rectangular outline as a whole, is integrally provided. At four corners of the mounting flange 3, mounting holes 4 are provided. The direct current static eliminator A can be detachably screwed to the blowing surface of the fan by using the mounting holes 4, and the electrode holder 1 is mounted when mounted. It is located on the periphery of the fan outlet surface. The shape of the electrode holder 1 is not limited to a circle, but may be a square or a polygonal ring.

FIG. 7 shows the electrode structure of the discharge electrode section 2. A discharge needle 5 is fixedly penetrated through the electrode holder 1 at each discharge electrode portion 2, and the tip of each discharge needle 5 is directed toward the center of the ring of the electrode holder 1, and the base end of the discharge needle 5 is connected to the electrode holder 1. It protrudes slightly from the center of the circular recess 6 provided on the outer peripheral surface. The connection terminal 7 is fixed to the protruding portion. A cylindrical insulating socket 8 is fixed to the outer periphery of the electrode holder 1 with its base end fitted into the circular recess 6. The socket 8 receives a plug 10 provided at the tip of an electric wire 9 for external wiring and connects the discharge needle 5 to the electric wire 9.
Female screw 11 for screwing the male screw is provided.

On the inner peripheral surface of the ring-shaped electrode holder 1, a pair of ground electrodes 12a and 12b are arranged on both sides of each discharge needle 5 in parallel to face each other, and are so-called parallel electrodes. The pair of ground electrodes 12a and 12b are L-shaped metal plates, and project from the inner peripheral surface of the electrode holder 1 by being fixed in opposite directions and fixed to the inner peripheral surface of the electrode holder 1. 5 is higher than the protrusion height.
The distance between the pair of ground electrodes 12a and 12b is the distance between the discharge needles 5 (the distance between the discharge needles 5 at positions facing each other across the center of the ring of the electrode holder 1, and the distance between the adjacent discharge electrodes 5 in the circumferential direction of the electrode holder 1). (The distance between the discharge needles 5).

As a specific example, when a voltage of 7 kV is applied to the discharge needle 5, the height of the ground electrodes 12 a and 12 b protruding from the inner peripheral surface of the electrode holder 1 is determined with reference to the protruding point of the discharge needle 5. 10 mm, the distance between the pair of ground electrodes 12a and 12b is 20mm, and the inner diameter (diameter) of the electrode holder 1 is 105.
mm, and the interval between the discharge needles 5 is 80 mm.

Although the four discharge electrode portions 2 have the same structure as described above, they have an arrangement relationship having a phase difference of 90 degrees on the electrode holder 1. 1
In order to make the electrodes facing each other with the phase difference of 80 degrees the same polarity, the two discharge needles 5 facing each other are connected to the electrode holder 1.
The DC eliminator A has two positive and negative electrodes each, which are connected via an internal wiring wire 13 laid on the outer periphery of the DC eliminator. The connection may be made by printed wiring.

Further, even if the ground electrodes 12a and 12b are independent one by one,
As shown in FIG. 8, both ends of a strip-shaped metal plate 12 having spring properties are bent, and one end thereof is connected to the ground electrode 12 of one of the discharge electrode portions 2 as shown in FIG.
a, the other end may be the ground electrode 12b of the other discharge electrode 2. Further, the number of discharge needles 5 may be three or more for each of plus and minus, or may be one.

The DC eliminator A has the above-described structure, and
When positive and negative DC high voltages are simultaneously applied to the two discharge needles 5 on the positive side and the two discharge needles 5 on the negative side from the wires 9 for external wiring, the positive and negative discharge needles An electric field is generated between the positive and negative discharge needles 5 and the ground electrodes 12a and 12b at the same time as the electric field is generated between the discharge needles 5a.
Since the distance between the ground electrodes 12a and 12b is much shorter, the electric field between the discharge needle 5 and the ground electrodes 12a and 12b becomes stronger, and corona discharge is mainly caused by the discharge needle 5 and the ground electrodes 12a and 12b. 12b. The discharge is stable as described above, and is less susceptible to a change in discharge at another discharge needle 5.

Such a DC eliminator A is, for example, shown in FIGS.
If it is attached to the outlet of the fan F as shown in FIG. In the fan F of this figure, the fan body 14 is supported on the stand 15 so as to be tiltable, so that the blowing angle can be adjusted.

FIG. 12 shows another embodiment of the present invention. In the DC static eliminator B, a plus-side discharge needle 18 and a minus-side discharge needle 19 are implanted in parallel in a rod-shaped electrode holder 17 accommodated in a rectangular casing 16 at a predetermined interval.
The tips of the discharge needles 18 and 19 face the centers of circular window holes 20 and 21 provided on the front surface of the casing 16, respectively. Inside the window holes 20 and 21, ring-shaped ground electrodes 22 and 23 are fixed to the electrode holder 17 so as to surround the discharge needles 18 and 19, respectively.

A battery 24 is removably accommodated in the casing 16 and a circuit board 25 is provided. On the circuit board 25, a positive / negative DC voltage is supplied from the battery 24 as a power source by a positive discharge needle. In this embodiment, positive and negative voltage doubler rectifier circuits 26 and 27 and a transformer 28 and the like to be applied to the negative electrode 18 and the negative discharge needle 19 respectively are mounted.

In the case of this DC eliminator B as well, when a positive or negative DC high voltage is applied to the positive and negative discharge needles 18 and 19 simultaneously, the positive and negative discharge needles 18 At the same time, an electric field is generated between the plus and minus discharge needles 18 and 19 and the respective ground electrodes.
Since the distance between the ground electrodes 22 and 23 is much shorter,
The electric field between the discharge needles 18 and 19 and the ground electrodes 22 and 23 becomes stronger, and corona discharge is mainly caused by the discharge needles 18 and 19.
And between the ground electrodes 22 and 23.

[0032]

As described above, according to the present invention, the ground electrode is opposed to each of the plus-side discharge needle and the minus-side discharge needle at an interval shorter than the distance between the plus and minus discharge needles. Since the corona discharge occurs mainly between the discharge needle and the ground electrode on each of the plus side and the minus side, even if the corona discharge current of one of the plus or minus polarity decreases, the other polarity is affected. In addition to providing no discharge, dust and the like are unlikely to adhere to the discharge needle, and both plus and minus can maintain stable discharge for a long time.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an experimental example for measuring a relationship between a charging potential of a charging plate and an effective discharging current.

FIG. 2 is a graph showing a measurement result of a relationship between a charging potential and an effective static elimination current performed on a conventional DC static eliminator and a general AC static eliminator.

FIG. 3 is a schematic diagram showing a case where plus and minus discharge needles are separated to a place where the discharge needles are not affected by an electric field due to static electricity of a charged object.

FIG. 4 is a graph showing discharge current characteristics when a plus / minus discharge needle has and does not have a ground electrode.
(A) is a plus discharge current, and (B) is a minus discharge current.

FIGS. 5A and 5B are graphs showing ion electric current characteristics when a ground electrode is provided with and without a ground electrode with respect to positive and negative discharge needles. FIG. 5A shows a negative plus ion current, and FIG. 5B shows a positive ion current.

FIG. 6 is a perspective view showing a DC static eliminator according to one embodiment of the present invention.

FIG. 7 is a sectional view showing a structure of a discharge electrode portion of the DC eliminator.

FIG. 8 is a front view showing another example of the ground electrode.

FIG. 9 is a partially simplified front view showing a usage example in which the direct-current static eliminator of FIG. 6 is attached to a blowout portion of a fan.

FIG. 10 is a side view of the fan.

FIG. 11 is a rear view of the same.

FIG. 12 is a perspective view showing a DC static eliminator according to another embodiment of the present invention.

[Explanation of symbols]

 A DC neutralizer 1 Electrode holder 5 Discharge needle 12a / 12b Ground electrode 18/19 Discharge needle 22/23 Ground electrode

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Kazuo Nakajima 2-6-7 Nakamachi, Setagaya-ku, Tokyo Kasuga Electric Corporation Dormitory F-term (reference) 5G067 DA01 DA18 DA21

Claims (5)

[Claims] 1. A DC static eliminator in which a positive discharge needle to which a positive DC high voltage is applied and a negative discharge needle to which a negative DC high voltage is applied are separated from each other and protrude from an insulating electrode holder. A direct current static eliminator characterized in that a ground electrode is arranged to face each of the plus side discharge needle and the minus side discharge needle at an interval shorter than the distance between the plus and minus discharge needles. 2. The direct-current static eliminator according to claim 1, wherein the ground electrode has a plate-like shape, and a pair of positive and negative discharge needles are arranged in parallel on opposite sides thereof in parallel. 3. The direct-current static eliminator according to claim 1, wherein the ground electrode is formed in a ring shape, and plus and minus discharge needles are respectively arranged at the center of the ring. 4. The direct-current static eliminator according to claim 1, wherein the protruding height of the ground electrode is higher than the protruding heights of the positive discharge needle and the negative discharge needle. 5. An insulative electrode holder is formed in a ring shape so that it can be attached to a blow-off portion of a fan, and a plus side discharge needle and a minus side discharge needle protrude from an inner peripheral surface thereof. The direct-current static eliminator according to claim 1, wherein the electrode is held.