JP2006281135A - Dust collector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dust collector in which charged dust does not flow outwardly. <P>SOLUTION: The dust collector is provided with: a discharge part 2 with a discharge electrode 21 and a counter electrode 22 for charging the dust which has passed through the discharge electrode 21 by corona discharge; a catcher part 3 for catching the dust charged in the discharge part 2; and a high voltage generation circuit 5 being switched between a positive potential and a negative potential at a prescribed time interval and applying a high voltage to the discharge part 2. As for the high voltage generation circuit 5, the switching cycle of the positive potential and the negative potential is set to be less than the time for the dust to reach the catching part 3 from the discharge part 2 when an air amount passing through the discharge part 2 is maximum and is set by a voltage for which the center value of the application voltage is a positive value. Thus, the charged dust does not easily flow outwardly. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a dust collector that electrically collects dust by corona discharge and electrically collects it, and more particularly to prevention of outflow of charged dust.

  2. Description of the Related Art Conventionally, as this type of dust collector, a technique for adjusting a voltage applied to a discharge unit so that dust charged by the discharge unit is reliably collected by the collection unit is known. This is because the discharge part for charging dust contained in the air by corona discharge, the collection part for collecting charged dust provided downstream thereof, and the potential of the discharge part with respect to the potential of the collection part. Voltage application means for applying a high voltage by switching between a positive potential and a negative potential at a predetermined time interval.

Then, in order to make the positive total charge amount and the negative total charge amount of the charged dust equal, the voltage applying means equalizes the positive potential period and the negative potential period so that the positive voltage absolute value and the negative voltage amount are negative. The voltage is applied to the discharge part so as to be equal to the absolute voltage value (see Patent Document 1).
JP 2004230277 A

  However, in Patent Document 1, there is no problem in making the switching period equal to the positive potential period and the negative potential period, but there are various restrictions on determining the switching period. For example, if the switching cycle is extremely shortened, the charges are electrically neutralized before reaching the collection section, and dust cannot be collected.

  In addition, if the switching cycle is lengthened, there is a problem that the dust that is not collected by the collecting unit flows out to the outside of the dust collecting device and stains the wall near the dust collecting device. Furthermore, even if the same dust collector is used, there is a problem that bothersomeness that must be changed so as to set a switching cycle in accordance with the air volume when the air volume is different.

  Further, according to the above-mentioned Patent Document 1, it is described that the positive voltage absolute value and the negative voltage absolute value should be equal. However, the Journal of the Electrostatic Society (Vo1.25, No. 2 (2001) p.102-104), the corona discharge current tends to be larger at the negative potential, so that dust having a total charge amount with a biased polarity is generated, so that dust is generated outside the dust collector. There is a problem of leakage. Thereby, the wall etc. near the outside of the dust collector are likely to get dirty.

  In addition to the above, in a dust collector using a general filtration filter, there is a problem that the ventilation resistance is increased by using a fine mesh filter if it is configured to remove fine dust contained in the air. .

  Accordingly, an object of the present invention is to provide a dust collector that prevents the charged dust from flowing out of the dust collector.

In order to achieve the above object, the technical means described in claims 1 to 4 are employed. That is, in the first aspect of the invention, the discharge unit (2) having the discharge electrode (21) and the counter electrode (22), and charging the dust that has passed through the discharge electrode (21) by corona discharge, A collecting unit (3) for collecting dust charged by the discharging unit (2), and a voltage applying means for applying a high voltage to the discharging unit (2) by switching between a positive potential and a negative potential at predetermined time intervals ( 5) In a dust collector comprising:
The voltage application means (5) has a period of time for dust to reach the collection section (3) from the discharge section (2) when the air flow rate through the discharge section (2) is maximum. In addition to being set below, the center value of the applied voltage is set by a positive voltage.

  According to the present invention, since the absolute values of the corona discharge currents at the positive potential and the negative potential are equal, the positive total charge amount and the negative total charge amount of the charged dust are generated more equally. . Thereby, the charged dust is coarsened by attracting each other and collected in the collection unit (3). Therefore, it is difficult for the charged dust to flow out of the dust collector through the collecting portion (3).

  In addition, by setting the switching cycle to be equal to or less than the time for the dust to reach the collection unit (3) from the discharge unit (2), the above-described cycle does not become longer than this, so that the charged dust is collected by the collection unit ( It does not flow out of the dust collector through 3). Therefore, the wall near the outside of the dust collector is not soiled by the charged dust.

  In the second aspect of the present invention, the voltage applying means (5) is such that the voltage applied to the discharge part (2) is applied by any one of a sine wave, a rectangular wave, a triangular wave, or a mountain wave. It is a feature. According to the present invention, a high voltage of a high potential or a negative potential can be output to the discharge part (2) in any waveform.

  The invention according to claim 3 is characterized in that the collection part (3) is an electret filter that electrically collects the dust charged in the discharge part (2). According to the present invention, the charged dust can be reliably collected by the collecting part (3), and the dust charged positively or negatively by the discharge part (2) is coarsened before reaching the collecting part (3). Therefore, even if the collection part (3) is a filter with a coarse mesh, fine dust can be removed. And since the mesh by the side of a collection part (3) can be roughened, ventilation resistance can be made small.

  The invention according to claim 4 is characterized in that the discharge electrode (21) is formed in a needle shape. According to the present invention, the positive total charge amount and the negative total charge amount of the dust charged in the discharge part (2) can be more reliably generated.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows a corresponding relationship with the specific means of embodiment mentioned later.

  Hereinafter, a dust collector according to an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic diagram showing the overall configuration of the dust collector 1, FIG. 2 is a perspective view showing the detailed shape of the discharge unit 2, and FIG. 3 is a characteristic diagram showing the output characteristics of the applied voltage output from the high voltage generation circuit 5. is there.

  As shown in FIG. 1, the dust collector 1 of the present embodiment includes a housing 11 that forms an air passage, a blower 12 that causes an air flow in the housing 11, a discharge unit 2, a collection unit 3, and a voltage. The high voltage generation circuit 5 is an application means.

  The discharge unit 2 includes a discharge electrode 21 and a counter electrode 22, and a corona discharge is generated between the electrodes 21 and 22 by applying a high voltage between the electrodes 21 and 22. The dust, which is fine particles in the air that has passed through, is charged to a positive charge or a negative charge.

  Specifically, as shown in FIG. 2, the discharge electrode 21 is made of a conductive material and needle-like electrodes are formed at regular intervals, and the counter electrode 22 is made of a conductive material in a plate shape. . The discharge electrode 21 and the counter electrode 22 are configured by laminating a plurality of discharge electrodes 21 and a counter electrode 22 in the ventilation path with a constant discharge interval. The discharge electrode 21 side is connected to the positive side of the high voltage generation circuit 5 via the electric circuit 23, and the counter electrode 22 side is connected to the positive side of the high voltage generation circuit 5.

  The high voltage generating circuit 5 is voltage applying means for applying a high voltage (for example, about 5 to 10 KV) between the electrodes 21 and 22, and one end thereof is connected to a battery 51 serving as a DC power source. As shown in FIG. 3, the output characteristics of the high voltage generation circuit 5 of the present embodiment are switched between a positive potential and a negative potential at a predetermined time interval (cycle) as a first feature, and the absolute value of the applied voltage is The waveform of the applied voltage having a positive center value is output as a sine wave.

  In addition, as a second feature, the switching period between the positive potential and the negative potential is equal to or less than the time for dust to reach the collection unit 3 to be described later when the air volume passing through the discharge unit 2 is maximum. It is set as follows. Thereby, the dust which passed the discharge electrode 21 by the corona discharge which generate | occur | produces between both the electrodes 21 and 22 is charged by the positive or negative electric charge. These features will be described in detail later in the operation.

  The collection unit 3 of the present embodiment uses an electret filter that is disposed on the downstream side of the air flow of the discharge unit 2 and electrically collects dust charged by the discharge unit 2. As is well known, this electret filter is capable of collecting dust charged by the discharge part 2 effectively by the action of static electricity because the material fibers are electretized.

  Further, since this type of electret filter has a high dust collection performance with a small pressure loss, dust charged positively or negatively in the discharge unit 2 reaches the collection unit 3 as in this embodiment. By attracting each other and gathering together, the dust is coarsened, so that even an electret filter with a coarse mesh can collect fine dust.

  In other words, the charged dust can be reliably collected by the collecting unit 3 by combining the discharge unit 2 for charging the dust and the collecting unit 3 made of a relatively coarse electret filter.

  Next, the operation of the dust collector 1 having the above configuration will be described. Air flows into the housing 1 by operating the air blowing means 12. In the discharge unit 2, either a positive potential or a negative high voltage (center value is the positive side) is applied between the electrodes 21 and 22. As a result, corona discharge occurs between the electrodes 21 and 22.

  Dust passing through the discharge electrode 21 is charged positively or negatively by this corona discharge. Here, the high voltage output circuit 5 is set such that the cycle of the positive potential is equal to the cycle of the negative potential, and the center value of the applied voltage is shifted to the positive side even when the potential is positive or negative. The absolute values of the positive and negative discharge currents become equal. As a result, an equal number of dusts charged to either positive or negative are generated.

  In addition, since the switching period between the positive potential and the negative potential is set to be equal to or less than the time when the dust reaches the collecting unit 3 at the maximum air volume, the dust charged to the positive or negative charge is reduced. Before reaching the collection unit 3, they are attracted to each other and gathered to be coarsened and collected by the collection unit 3.

  Thereby, the dust charged to either positive or negative does not pass through the collection part 3. Accordingly, charged dust does not flow out of the dust collector 1. In addition, the electret filter of the type with which the mesh of the collection part 3 is coarse may be sufficient because it attracts and dusts each other before the charged dust reaches the collection part 3.

  In the present embodiment, the electret filter is used for the collection unit 3, but the present invention is not limited thereto, and a filtration type medium performance filter or high performance filter may be used. Moreover, you may arrange | position combining the discharge part 2 and the filtration type medium performance filter or a high performance filter in the dust collector using an ultrahigh performance HEPA filter. Furthermore, in the case of a dust collector using a filtration type medium performance filter or high performance filter alone, the discharge part 2 and the coarse dust filter may be disposed in combination.

  According to the dust collector 1 according to the above-described embodiment, the high voltage generation circuit 5 collects from the discharge unit 2 the switching cycle between the positive potential and the negative potential when the air volume passing through the discharge unit 2 is maximum. The time is set to be equal to or less than the time when the dust reaches the portion 3 and the center value of the applied voltage is set to a positive value.

  As a result, the absolute values of the corona discharge currents at the positive potential and the negative potential become equal, and as a result, the positive total charge amount and the negative total charge amount of the charged dust are generated more equally. Thereby, the charged dust is coarsened by attracting each other and collected by the collection unit 3. Therefore, it is difficult for the charged dust to flow out of the dust collector 1 through the collector 3.

  In addition, by setting the switching cycle to be equal to or less than the time for the dust to reach the collecting unit 3 from the discharge unit 2, the charged dust passes through the collecting unit 3 and does not collect the dust. It does not flow out of the device 1. Accordingly, the wall near the outside of the dust collector 1 is not soiled by charged dust.

  By using an electret filter that electrically collects dust charged by the discharge unit 2 in the collection unit 3, the charged dust can be reliably collected by the collection unit 3 and positive or negative by the discharge unit 2. Since the negatively charged dust is coarsened before reaching the collection unit 3, even if the collection unit 3 is a coarse filter, fine dust can be removed. And since the mesh by the side of the collection part 3 can be roughened, ventilation resistance can be made small.

  Further, since the discharge electrode 21 is formed in a needle shape, the corona discharge generated between the electrodes 21 and 22 is more stable, and the positive total charge amount and the negative charge amount of dust charged in the discharge unit 2 are reduced. It is possible to more reliably generate the total charge amount equally.

(Other embodiments)
In the above embodiment, the applied voltage applied between the electrodes 21 and 22 is output as a sine waveform by the high voltage generation circuit 5, but the present invention is not limited to this. The applied voltage having the waveform shown in a) to FIG. 4A is a rectangular wave, FIG. 4B is a triangular wave, and FIG. 4C is a mountain wave.

It is a mimetic diagram showing the whole dust collector 1 composition in one embodiment of the present invention. It is a perspective view which shows schematic shape of the discharge part 2 in one Embodiment of this invention. It is a characteristic view which shows the output voltage characteristic of the high voltage generation circuit 5 in one Embodiment of this invention. (A) thru | or (c) is a characteristic view which shows the output voltage characteristic of the high voltage generation circuit 5 in other embodiment.

Explanation of symbols

2 ... discharge part 3 ... collection part 5 ... high voltage generation circuit (voltage application means)
21 ... Discharge electrode 22 ... Counter electrode

Claims (4)

A discharge section (2) having a discharge electrode (21) and a counter electrode (22), and charging the dust that has passed through the discharge electrode (21) by corona discharge;
A collection unit (3) for collecting dust charged in the discharge unit (2);
In a dust collector comprising a voltage applying means (5) for applying a high voltage to the discharge part (2) by switching between a positive potential and a negative potential at predetermined time intervals,
The voltage application means (5) has a switching period between a positive potential and a negative potential from the discharge portion (2) to the collection portion (3) when the amount of air passing through the discharge portion (2) is maximum. The dust collector is set to be equal to or less than a time when dust reaches and is set by a voltage having a positive central value of the applied voltage.   The voltage applying means (5) is characterized in that the voltage applied to the discharge part (2) is applied by any one of a sine wave, a rectangular wave, a triangular wave, and a mountain wave. The dust collector described.   The dust collector according to claim 1, wherein the collection part (3) is an electret filter that electrically collects dust charged by the discharge part (2).   The dust collector according to any one of claims 1 to 3, wherein the discharge electrode (21) is formed in a needle shape.

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