JPS5888048A - Electrostatic precipitator power supply - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power supply device for electrical industrial dust equipment, and more particularly to a power supply device for electrical industrial dust equipment suitable for collecting high-resistance dust with high efficiency.

2. Description of the Related Art Electrical industrial dust equipment is one type of equipment for separating and collecting solid or liquid fine particles (hereinafter referred to as dust) suspended in a gas such as a processing gas.

In general, electrical industrial dust equipment is provided with a dust collection electrode formed from a flat plate and a discharge electrode usually formed from a thin wire, etc., with a predetermined distance maintained between the dust collection electrode and the discharge electrode. By applying a voltage, an electric field accompanied by corona discharge is formed between the two electrodes. When processing gas is introduced into the electrical industrial dust equipment configured in this way, the dust in the processing gas is charged by ions generated by corona discharge, and the charged dust is deflected by the electric field and directed to the dust collecting electrode. It is attracted to the surface and collected.

The dust collected in this way is deposited in a layer on the surface of the dust collection electrode, but the dust with high resistivity (
In the case of high-resistance dust), the electric field strength in the dust layer is increased and reverse ionization discharge occurs, which may significantly reduce the dust collection performance. This reverse ionization phenomenon occurs when the ionic current generated by corona discharge at the discharge electrode flows into the dust layer on the surface of the dust collecting electrode, and the product of the current density ID and the resistivity ρ of the dust layer is the dielectric breakdown strength E of the dust layer. Nine times beyond, that is, ρゎ工. > E, and is generally thought to occur when the specific resistance of dust is 1011
High-resistance dust with a resistance of Ω or more is said to be a problem.

Therefore, as a method for efficiently collecting high-resistance dust, the electric current of the dust layer is A method has been proposed for suppressing the occurrence of back ionization by reducing the degree It-. At t9, the DC component voltage is set close to the corona start voltage at which corona discharge is sustained, so that the DC component discharge current is minute, and the superimposed AC component voltage value is controlled to provide the required voltage for charging the dust. By supplying an ionic current, the current density in the dust layer is reduced while ensuring the electric field strength and ionic current necessary for dust collection, thereby collecting high-resistance dust with high efficiency.

Conventionally, as a power supply device that generates a DC voltage on which an AC voltage is superimposed as described above, the one shown in Fig. 11 or Fig. 2 is known.

Items with the same reference numerals in Figures 1 and 2 have the same functions.

As shown in FIG. 1, an AC power source 3 is connected to the primary winding of a transformer 1 for generating DC voltage and the primary winding of a transformer 2 for generating AC voltage. The secondary winding of the transformer 1 is connected to a smoothing capacitor 5 via a rectifier circuit 4.

One side of the smoothing capacitor 5 is grounded, and the other side is connected to the discharge electrode 6 through the secondary winding of the transformer 2.

Dust collection electrode? Fi is grounded.

With this structure, the AC voltage boosted by the transformer 1 is rectified by the rectifier circuit 4, and the ripple current is removed by the smoothing converter 5 to become a DC voltage.

An alternating current voltage boosted by the transformer 2 is superimposed on this direct current voltage and is applied to the discharge electrode 6.

However, in the nine power supply devices described above, since DC voltage is applied to the low voltage output side of the secondary winding of the transformer 2, the entire transformer 2 must be lifted from the ground potential, and insulation equipment is required. It has the disadvantage of being expensive.

Therefore, the power supply device shown in FIG. 2 has been devised, which eliminates the need for the above-mentioned insulation equipment.

As shown, the DC voltage generating section is formed in the same manner as the conventional example shown in FIG. 1, and the high voltage side of the smoothing capacitor 5 is connected to the discharge electrode 6 through a resistor 8t. One end of the secondary winding of the transformer 2 for generating AC voltage is grounded, and the other end is connected to the discharge electrode 6 via the capacitor 9.

With this configuration, the low voltage side of the secondary winding of the transformer 2 is at ground potential, so the above-mentioned insulation equipment is not required. Further, as in the conventional example shown in the Is1 diagram, a DC voltage on which an AC voltage is superimposed can be applied to the discharge electrode 6.

However, in the conventional examples shown in FIGS. 1 and 2, transformers for DC voltage and AC voltage must be provided, which increases the equipment cost of the power supply device, and This has the disadvantage that the configuration is complicated.

SUMMARY OF THE INVENTION An object of the present invention is to provide a power supply device for an electric industrial device that can generate a DC voltage with an AC voltage superimposed thereon using a simple configuration and is highly economical.

The present invention provides a power source configured by connecting one end of an output terminal of a transformer to a dust collecting electrode and the other end to a discharge electrode via a capacitor, and connecting a rectifier in parallel between the dust collecting electrode and the discharge electrode. By making the device into a device, a DC voltage with an AC voltage superimposed can be generated with a simple configuration, and the device can be excellent in economical efficiency.

The present invention will be explained below using illustrated embodiments.

FIG. 3 shows the circuit configuration of one embodiment of the present invention. In the drawings, the same reference numerals as those in the conventional example shown in FIGS.

As shown in FIG. 3, an AC power source 3 is connected to the primary winding of the transformer 11. One end of the secondary winding of this transformer 11 is connected to the discharge electrode 6 via the capacitor 12, and the other end is grounded together with the dust collecting electrode 7. diode 13
An anode and a cathode are connected to a discharge electrode 6 and a dust collection electrode 7, respectively.

With this configuration, the AC voltage input from the AC power supply 3 is stepped up by the transformer 11, and an AC voltage having a peak value Vp is induced in the secondary winding. During the half cycle in which the output voltage on the anti-ground side of the secondary winding becomes positive, the capacitor 12 is charged through the diode 13 until its terminal voltage reaches the peak value Vp. Therefore, the charging voltage V is the voltage between the discharge electrode 6 and the dust collection electrode 7, which is the sum of the terminal voltage Wp of the capacitor 12 and the output voltage of the transformer 11. Applied as P. This charged direct voltage output AC voltage (peak value Vp) is superimposed.

In addition, since the above-mentioned peak value Vp matches the DC component voltage, vp is set to suppress reverse ionization in high resistance dust collection.
It is desirable to set the value close to the corona starting voltage value of the applied dust collector.

Therefore, according to this embodiment, a DC voltage on which AC voltage is superimposed can be supplied to electrical industrial equipment using a simple power supply device consisting of a single transformer, which significantly reduces equipment costs. High resistance dust can be collected with reduced and low cost equipment.

FIG. 5 shows a circuit configuration diagram of another embodiment to which the present invention is applied. Components with the same reference numerals as in the embodiment shown in FIG. 3 have the same structure and the same function.

In FIG. 5, the difference from the embodiment shown in FIG. 3 is as follows.
A mechanism is provided that can turn on and off the primary alternating current voltage of the transformer 11 at arbitrary intervals. That is, transformer 1
A thyristor 14 is inserted and connected to the primary side circuit of 1, and the dust on this thyristor 14 is the thyristor? It is connected to the l1lJ control circuit IV5.

Further, a voltage signal from the AC power supply 3 is input to the thyristor control circuit 15 .

Because of this configuration, the thyristor control circuit 1
5 is activated to control the conduction/disconnection of the thyristor 14, the primary voltage is intermittently applied to the transformer 11 and becomes K. As a result, a charging voltage having a waveform shown in FIG. 6 is applied between the discharge electrode 6 and the dust collection electrode 7 of the electrical dust device. As shown in the figure, when the cyrisk is cut off, only the terminal voltage of the capacitor 12 remains, and the corona discharge is stopped.

Therefore, for example, in the case of high-resistance dust with a specific resistance of 1018 Ω·■ or more, even if a small discharge current flows, reverse ionization may occur and dust collection may be inhibited, but according to this embodiment, By providing a pause time for corona discharge,
Since the emitted '11i'It flow can be controlled as desired, it is possible to suppress reverse ionization and collect dust with high efficiency even if it is high-resistance dust with a specific resistance of IQIIΩ or higher. be.

Note that the pause time of the corona discharge described above is mainly set according to the specific resistance of the dust, but if the body 1b time is too long, there will be a shortage of ions tm that charge the dust, and the average electric field strength will decrease significantly. Since this may result in a decrease in performance, the pause time for corona damage should be set in the range of 1 to 5 cycles for every 2 to 10 cycles of AC voltage.

As explained above, according to the present invention, it is possible to generate a DC voltage on which an AC voltage is superimposed with a simple configuration, and the equipment cost can be reduced. It can be fruitful from a social perspective.

[Brief explanation of the drawing]

Figures 1 and 2 are circuit configuration diagrams of a conventional power supply device, Figure 3 is a circuit configuration diagram of an embodiment of the present invention, and Figure 4 is a charging voltage waveform of the embodiment shown in Figure 3. 5 is a circuit configuration diagram of another embodiment of the present invention, and FIG. 6 is a diagram showing the charging voltage waveform of the embodiment shown in FIG. 6... 4 poles, 7... Dust electrode, 11... Transformer, 12... Capacitor, 13... Diode,
14... Thyrist j, 15... Thyristor control circuit. Figure 1 4' Figure 2 Figure 3 Figure 5

Claims (2)

[Claims] (1) In a power supply device for an electrical industrial dust equipment, which is provided to supply a charging voltage to a discharge electrode arranged in parallel with a dust collection electrode at a predetermined distance, one end of the output terminal is connected to the discharge electrode via a capacitor. A transformer connected to the round dust collecting electrode with its other end grounded and connected to the round dust collecting electrode; and a rectifier connected in parallel between the discharge electrode and the dust collecting electrode. Device power supply. (2) In a power supply device for an electrical industrial dust equipment which is intended to supply a charging voltage to a discharge electrode arranged in parallel with a dust collecting electrode at a predetermined distance, one end of the output terminal 0 is connected to the discharge electrode via a capacitor. a transformer connected to the dust collecting electrode with the other end grounded; a rectifier connected in parallel between the discharge electrode and the dust collecting electrode; 2 to 1O cycles of the primary AC voltage of the transformer; - for 1 to 5 cycles per cycle
1. A power supply device for electrical industrial equipment, comprising: a current interrupting control circuit for interrupting alternating current; and;