JPH07132249A - Electrostatic air cleaner - Google Patents

Abstract

PURPOSE:To provide an electrostatic air cleaner in which a spark current generated between electrodes of the electrostatic air cleaner is restrained and which excels in safety. CONSTITUTION:In an electrostatic air cleaner consisting of a charge part 1 and a dust collecting part 2, a low voltage electrode 12 of the charge part 1 and a dust collecting electrode 22 of the dust collecting part 2 each are electrically isolated from a counter earth. A current limiter 4 is installed in an electric circuit between the low voltage electrode 12 and the dust collecting electrode 22, and the earth. DC high voltage is applied from a high voltage power source 3 is applied to between a discharge electrode 11 of the charge part and the earth, and between a high voltage electrode 21 of the dust collecting part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic air cleaner for removing dust floating in the atmosphere, and more particularly, it has a function of suppressing a spark current generated between both electrodes of a high voltage electrode and a low voltage electrode. And an electrostatic air purifier.

[0002]

2. Description of the Related Art As an air purifier that removes dust floating in the atmosphere, an electrostatic air purifier that efficiently removes cigarette smoke having a particularly small particle size is widely used.
The electrode configuration is a two-stage charging type in which a dust charging part is provided on the gas inflow side and a dust collecting part is provided on the downstream side. The dust charging unit applies a high DC voltage between the discharge electrode and the ground electrode to generate a corona discharge and gives an electric charge to the dust passing through the discharge field. The section forms a electric field by applying a DC high voltage between the high-voltage pole and the dust-collection pole facing each other with parallel flat plates maintaining a predetermined interval. The dust charged in the charging unit moves from the high pressure side toward the dust collecting electrode side by the action of the electric field in the dust collecting unit, is captured by the dust collecting electrode, and the purified air is discharged to the outside of the device.

Such an electrostatic air purifier is not only used as an air purifier alone, but also installed in the air inlet of a package type air conditioner to circulate in order to obtain a comfortable indoor environment. It is also used to remove dust in the air in addition to adjusting the temperature and humidity of the air to be used. The charging part aims to give an electric charge to the dust, so it is difficult for dust to adhere to the grounding electrode, but the dust collecting part positively attaches the charged dust to the collecting electrode. Dust adheres to and accumulates on the ground electrode, which narrows the distance between the high-voltage electrode and the dust-collecting electrode, and causes a spark to easily occur between the two electrodes. In addition, in order to improve the dust collection efficiency of the electrostatic air purifier, the voltage applied to the dust collection unit is usually increased until just before the spark is generated, which is a cause of the spark. When sparks occur, there are the following problems. Although the energy of the spark is substantially small, electromagnetic waves may be generated from the discharge part and may damage other electronic devices. Further, for safety of the device, it is desirable to suppress spark discharge as much as possible. Since it is difficult to completely prevent this spark from the viewpoint of the structure of the device, if a spark occurs, it is disclosed in, for example, JP-B-54-20692 or JP-A-5-31398 in order to suppress the scale as much as possible. As described above, when a spark occurs due to a high resistance in the high voltage circuit that energizes the high voltage pole of the dust collecting part from the high voltage power supply, there is a method to suppress the surge current by absorbing the surge voltage by the high resistance. Proposed.

[0004]

The above spark current suppressing method is effective in suppressing the energy supplied from the power source by the spark discharge. However, since the electrode configuration of the dust collecting part is composed of parallel flat plates with a predetermined interval,
The dust collecting part itself plays the role of an air condenser, and electric charges are always accumulated during operation. The disclosed spark current suppressing method has a problem that the spark current cannot be suppressed because the current due to the accumulated charges does not pass through the resistor when the spark occurs.

An object of the present invention is to provide an electrostatic air purifier excellent in safety that efficiently suppresses spark current energy generated between a high-voltage electrode and a dust collecting electrode.

[0006]

The above object can be achieved as follows. That is, an electrostatic air cleaner composed of a discharge electrode, a dust charging part composed of a low-pressure electrode facing the discharge electrode, and an electrode group composed of a dust collection part in which the electrodes of the high-voltage electrode and the collection electrode are opposed to each other by a parallel plate. In the container, the low-voltage electrode of the charging part and the dust-collecting electrode of the dust-collecting part are electrically insulated from the ground, and a current limiter is provided in the electric circuit between the low-voltage electrode and the dust-collecting electrode and the ground, and A high DC voltage is applied between the discharge electrode of the charging section and the ground, and between the high-voltage electrode of the dust collecting section and the ground.

[0007]

In the dust charging section, when a high DC voltage is applied between the discharge electrode and the ground, corona discharge occurs between the discharge electrode and the low voltage electrode. On the other hand, when a DC high voltage is applied between the high voltage electrode of the dust collecting part and the ground, an electrostatic field is generated between the high voltage electrode and the dust collecting electrode.
The dust particles in the air sucked into the charging portion are charged by corona discharge and are collected by the dust collecting electrode by the electric field action in the dust collecting portion. When the dust collecting electrode pollutes the dust collecting electrode and spark discharge occurs, the electric charge stored in the dust collecting electrode tries to flow instantaneously, but a current limiter provided between the dust collecting electrode and the ground, for example, When the inductance is used, a counter electromotive force is generated to absorb the spark current and the generation of electromagnetic waves due to the spark is suppressed. Since the potential of the low-voltage electrode of the charging part and the dust-collecting electrode of the dust-collecting part are usually the same, the same current limiter suppresses the spark current between the discharge electrode of the charging part and the low-voltage electrode. can do.

[0008]

Embodiment An embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an explanatory diagram of electrodes of the electrostatic air purifier of the present invention. Reference numeral 1 indicates a dust charging portion, and 2 indicates a dust collecting portion. Charging part 1
Is usually composed of a line-to-plate, a linear electrode is used for the discharge electrode 11, and a plate electrode is used for the low-voltage electrodes 12, 12 '. The dust collecting part 2 is composed of a high-voltage electrode 21 and dust collecting electrodes 22, 22 ', and the electrode shape thereof is a parallel plate electrode. As described above, the electrostatic air purifier has a plurality of sets of electrodes each including the discharge electrode 11, the low-voltage electrode 12, the high-voltage electrode 21, and the dust collection electrode 22 as a pair.

In the conventional electrode structure, the low voltage electrode 1 of the charging unit 1
2, and the dust collecting electrode 22 of the dust collecting portion 2 is a ground electrode, but the present invention is characterized in that the current limiter 4 is used between the low voltage electrode 12 and the dust collecting electrode 22 and the ground. is there. The current limiter 4 uses an inductance or a high resistance body. In the electrostatic air purifier, a high voltage power supply 3 for applying to the charging unit 1 and the dust collecting unit 2 is usually a voltage doubler rectifying power supply, and the voltage applied to the dust collecting unit is applied to the charging unit. An example in which ½ of the applied voltage is applied is shown. The generated voltage of the high voltage power supply 3 is not limited to the double voltage power supply. A high voltage terminal for direct current high voltage is connected to the discharge electrode 11 and the high voltage electrode 21 from the high voltage power source 3, while the low voltage terminal (earth) is connected to the low voltage electrode 1
2 and the dust collecting electrode 22 is connected to the ground side through the current limiter 4. First, the dust collecting action in such an electrode configuration will be described. Discharge electrode 11 and low-voltage electrodes 12, 12 '
When the air 5 containing dust is introduced into the corona discharge field by causing corona discharge between and, the dust is charged and then introduced into the dust collecting portion 2. In the dust collecting part 2, an electric field is formed between the high voltage electrode 21 and the dust collecting electrodes 22, 22 ', so that the charged dust is captured by the dust collecting electrodes 22, 22' by the Coulomb force and the air is purified. The clean air 6 is discharged outside the device. On the other hand, the high voltage electrode 21 and the dust collecting electrode 22 of the dust collecting unit 2,
The parallel plate electrode group composed of 22 'has the purpose of trapping dust, which acts as an air condenser and stores the electric charge supplied from the high voltage power source 3. Here, when a spark is generated between the high-voltage electrode 21 and the dust collecting electrode 22, all the electric charges stored between the electrodes are instantly discharged. At this time, the discharge of electric charge appears as a spark current, so it is necessary to suppress the discharge of this electric charge.

Next, the function and effect of the current limiter 4 of the present invention will be described in comparison with the conventional spark suppression method. FIG. 3 shows a conventional spark suppression method, that is, when a high resistance is provided between the high voltage power source 3 and the high voltage electrode 21, when a spark is generated between the high voltage electrode 21 and the dust collecting electrode 22, The oscilloscope shows changes in the current flowing from the pole 22 to the ground and the voltage applied to the high-voltage pole 21. on the other hand,
FIG. 4 shows a case where the current limiter 4 according to the present invention shown in FIG. 1 is used, the current flowing from the dust collecting electrode 22 to the ground through the current limiter 4 at the time of spark generation and the high voltage electrode 21 The change in the applied voltage is shown on the oscilloscope as described above. In the conventional spark suppression method, when the spark is generated, the current due to the charge accumulated in the dust collecting portion does not pass through the high resistance body, so that the spark current cannot be suppressed and a strong current flows. However, according to the present invention, as shown in FIG. 4, since the inductance (or high resistance) provided between the dust collecting electrode 22 and the ground absorbs the surge voltage, almost no current flows due to the spark, and the electromagnetic wave is generated. Hateful. In this case, since the low-voltage electrode 12 of the charging unit 1 and the dust-collecting electrode 22 of the dust-collecting unit 2 have the same potential, even if a spark occurs not only in the dust-collecting unit 2 but also in the charging unit 1, the current limiter Since 4 is provided on the ground side, there is an effect that the spark current can be suppressed.

FIG. 2 shows a spark current limiter 4 and a dust collector 2
A discharge tube 7 is provided in parallel with the spark current limiter 4 in order to protect the above. If the spark current limiter 4 is broken, a high voltage may be induced between the dust collecting electrode and the ground. In that case, the discharge tube 7 can discharge and protect. FIG. 5 is an explanatory diagram of a circuit that detects a current flowing through the discharge tube 7 and protects the high-voltage power supply. That is, since an abnormal current may flow from the power supply and the high-voltage power supply may be burnt out, voltage control such as lowering the voltage applied to the electrodes is performed. In this method, when a current flows through the discharge tube, the resistor 8 provided in the circuit detects the current and the oscillator 9 controls the voltage.

[0012]

According to the electrostatic air purifier of the present invention, the spark current can be almost completely suppressed, so that there is no electromagnetic interference to electronic equipment and the spark current is suppressed. Safe to.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of electrodes of an electrostatic air purifier according to the present invention.

FIG. 2 is an explanatory diagram of a spark current limiter according to the present invention.

FIG. 3 is a conventional spark current waveform diagram when a spark is generated.

FIG. 4 is an explanatory diagram of a spark current suppressing effect according to the present invention.

FIG. 5 is an explanatory diagram of high voltage power supply control when a spark occurs according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Dust charging part, 11 ... Discharge electrode, 12 ... Low voltage electrode, 2 ... Dust collecting part, 21 ... High voltage electrode, 22 ... Dust collecting electrode, 3 ... High voltage power supply, 4
... spark current limiter, 7 ... discharge tube, 9 ... oscillator.

Claims (5)

[Claims] 1. A static charging device comprising a discharge electrode, a charged portion of dust consisting of a low-voltage electrode facing the discharge electrode, and an electrode group consisting of a dust collecting part in which the electrodes of the high-voltage electrode and the dust collecting electrode face each other with a parallel plate. In an electric air purifier, a low-voltage electrode of the charging part and the dust-collecting electrode of the dust-collecting part are electrically insulated from a ground, respectively, and an electric circuit of the low-voltage electrode and the dust-collecting electrode and the ground is provided. A spark current limiter is provided in the electrostatic discharge device, and a high DC voltage is applied between the discharge electrode of the charging unit and the ground, and between the high voltage electrode of the dust collecting unit and the ground. Electric air purifier. 2. The electrostatic air purifier according to claim 1, wherein the spark current limiter is an inductor or a resistor. 3. An electrostatic air purifier having a circuit configuration in which the spark current limiter of claim 1 can be shared by a charging section and a dust collecting section. 4. The electrostatic air purifier according to claim 1, wherein discharge tubes are provided in parallel at both ends of the spark current limiter. 5. An electrostatic device comprising a current detection circuit flowing through the discharge tube according to claim 4, and means for detecting a current flowing through the discharge tube and controlling a high voltage applied to the charging section and the dust collecting section. Air purifier.