KR19980032006A - Pulse Charged Electrostatic Precipitator Circuit and Electrostatic Precipitator - Google Patents

Abstract

Its purpose is to provide an electrostatic precipitator circuit capable of generating a pulse waveform suitable for a pulse charged electrostatic precipitator. An input contact point, an output terminal to which a precipitator electrode is connected, and an accumulation capacitor connected between a ground potential and an input contact point are provided. And a recovery capacitor having a ground potential applied to one of the electrodes, a current having a first contact point and a second contact point connected to the common contact point and the common contact point having switching means, and the common contact point of the non-grounding electrode of the storage capacitor. A first current path connected between the first contact point and the output terminal including the series circuit of the inductor and the diode, and a non-grounded electrode of the output contact point and the recovery capacitor including the series circuit of the inductor and the diode. A second current path and a third current path for connecting the non-grounded electrode and the second contact of the recovery capacitor, including the series circuit of the inductor and diode. Pulse-charged electrostatic precipitator circuit and electrostatic precipitator.

Description

Pulse Charged Electrostatic Precipitator Circuit and Electrostatic Precipitator

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic precipitator, and more particularly, to a pulse charged type electrostatic precipitator.

The pulse charge method of the electrostatic precipitator has a great effect on the miniaturization of the precipitator. However, the pulse charge device is generally expensive, especially when the dust collector main body is below the medium scale, the price of the dust collector main body is not very expensive, and the advantage of the miniaturization of the dust collector main body is offset by the increase in the price of the charging device. It is often done. Therefore, the price reduction of a pulse charge apparatus is desired.

As the pulse power source for the electrostatic precipitator, those using semiconductor elements such as thyristors as the switch elements and those using rotating spark gaps are known.

5 illustrates a pulse power supply using a rotating sprocket gap according to the related art. Fig. 5A shows the circuit configuration, and Fig. 5B shows its electrical characteristics.

In Fig. 5A, a DC power supply DC is formed by a transformer and a diode bridge supplied with an AC current from the AC power supply. The positive pole of the DC power supply DC is grounded and is connected to one stop electrode of the rotary spark gap RSG ₃ through the impedance Z which is the negative pole.

The other electrode of the impedance (Z) of the rotating spark gap interconnection point (RSG ₃₎ is connected to one electrode of the storage capacitor (C _S), storage capacitor (C _S) of is grounded.

The rotary spark gap RSG ₃ forms a spark gap between the stationary electrode and the rotary electrode, which is rotated by the motor M. As shown in FIG. The other stationary electrode of the rotary spark gap RSG _{3 is} connected to the electrode of the dust collector electrode EP (called a discharge electrode) via an inductance L ₁₀ , and the other electrode of the dust collector electrode EP (dust collector electrode). Is grounded.

When the rotary spark gap RSG ₃ is conducted, an LC resonant circuit including an accumulation capacitor C _S , an inductance L ₁₀ , and a dust collector electrode EP is formed. The negative current accumulated in the storage capacitor C _S excites the resonant current in the LC resonant circuit.

Fig. 5B shows the characteristics of the rotary spark gap type pulse power supply shown in Fig. 5A. In the figure, the horizontal axis represents time t, and the vertical axis represents negative voltage of the dust collector electrode EP. During the period when the rotary spark gap RSG ₃ is conducting, a current having an inherent resonance frequency is excited in the LC resonance circuit. In the characteristic shown, the vibration period is several hundred Hz, and several cycles of vibration occur in this period.

When the rotary spark gap RSG ₃ is not conducting, the resonance current does not flow through the LC resonant circuit and the vibration is stopped. At this time, if the voltage remaining on the dust collector electrode EP is equal to or higher than the corona starting voltage, the charge accumulated in the dust collector electrode EP is reduced by the corona discharge, and the negative voltage of the dust collector electrode EP is exponentially increased. Lowers.

Thus, the rotary spark gap pulse power supply having the circuit configuration shown in Fig. 5A can form a single pulse waveform, and the rotary spka gap can only form a multiple pulse waveform having vibration for several cycles until it becomes non-conductive. none.

The voltage waveform desired for the electrostatic precipitator is a constant negative voltage of which the single pulse shape is a high negative voltage and the base voltage in other periods, and the voltage waveform shown in Fig. 5B is suitable as a pulse waveform for the electrostatic precipitator. Can't.

FIG. 5C shows an electronic circuit of thyristor and diode that can be used in place of the rotating spark gap RSG ₃ of FIG. 5A. This circuit is constructed by connecting the thyristor S ₁₀ and the diode D ₁₀ in anti-parallel. S ₁₀ is actually configured by connecting a plurality of thyristor elements in series to withstand high voltages.

When the thyristor S ₁₀ is conducted, the resonance current is excited to the LC resonant circuit as in the case of Fig. 5A. After the current flows in the forward direction of the thyristor S ₁₀ , the current flows in the forward direction of the diode D ₁₀ . When the thyristor S ₁₀ is not conducting in the period in which the current flows through the diode D ₁₀ , the resonance current flows only for one cycle and then does not flow thereafter.

However, in practice, many of the thyristor elements constituting the thyristor S ₁₀ do not become non-conductive, so that they cannot withstand the high voltage as a whole, and therefore, they cannot be completely conducted. As a result, the same vibration waveform as that of Fig. 5B appears, and the thyristor is more expensive than the rotary spark gap.

FIG. 6 is a circuit diagram of an electrostatic precipitator devised by the present inventors to solve the above problem and disclosed in a cylinder example of Japanese Patent Laid-Open No. 6-343898. A rotary spark gap (RSG ₄₎ in series with a diode (D ₁₂₎ is in parallel to the inserted by rotary spark gap (RSG ₄₎ and a diode (D ₁₂₎ a series circuit diode (D ₁₂₎ and a reverse diode (D ₁₃ ) Is connected.

Since the diodes D ₁₂ and D ₁₃ are connected in anti-parallel, the excited resonant current flows through the diode D ₁₂ in the half cycle, and the other half cycle flows through the diode D ₁₃ .

While the resonant current is a half cycle through the diode D ₁₃ , no current flows in the rotating spark gap RSG ₄ . At this time, the arc plasma generated in the rotary spark gap RSG ₄ disappears. In order to ensure the disappearance of the arc plasma, it may be sprayed on the gap portion where the arc plasma is generated.

The circuit configuration shown in Fig. 6 makes the rotary spark gap RSG ₄ non-conductive when the resonance current flows for half a period. However, when the forward voltage is generated again with respect to the diode D ₁₂ due to the oscillation by the LC resonant circuit, the rotary spark gap RSG ₄ recurminates.

In order to prevent re-ignition, the rotation electrode of the rotary spark gap RSG ₄ may be rotated at a sufficient angle before the second forward voltage is generated with respect to the diode D ₁₂ to obtain a gap length that does not spark. One way to do this is to make the tip speed of the rotating electrode more than a few hundred m / s.

As described above, it is difficult to manufacture a rotating spark gap that rotates at a high speed, and the driving power is increased, and the noise is increased because the tip of the rotating electrode exceeds the speed of sound.

An object of the present invention is to provide a circuit for an electrostatic precipitator that can generate a pulse waveform suitable for an electrostatic precipitator while using a low-cost rotary spark gap without re-ignition even if its rotation speed is low.

According to one aspect of the present invention, an input terminal to which a DC voltage is applied, an output terminal to which a dust collector electrode is connected, a storage capacitor having a ground potential at one electrode, and the other electrode connected to the input terminal; A recovery capacitor having a ground potential applied to an electrode of the first contact state; and a first conduction state connecting the common contact point and the first contact point as a current switching means having a common contact point, a first contact point and a second contact point; A second conduction state connecting the second contact point and a neutral state in which the common contact point is not connected to any of the first and second contacts, wherein the common contact point is formed by the current connected to the non-grounding electrode of the storage capacitor. A first current path connecting the first contact point and the output terminal, the second inductor and the second diode, comprising a switching means, a series circuit of the first inductor and the first diode. And a non-grounded electrode of the recovery capacitor, wherein the polarity of the electrode of the output terminal of the second die is opposite to the polarity of the first diode. A second current path and a series circuit of the third inductor and the third diode, wherein the non-grounding electrode of the recovery capacitor and the second contact are connected, and the polarity of the recovery capacitor side electrode of the third diode is An electrostatic precipitator circuit is provided having a third current path having a polarity opposite to that of the second diode.

The accumulation capacitor is charged through the input terminal. When the switching means for current is brought into the first conducting state, charge is transferred from the accumulation capacitor to the dust collector electrode connected to the output terminal via the first current path. Since the first diode is connected to the first current path, the electric charge flowing into the dust collector electrode does not flow back toward the accumulation capacitor. The charge accumulated in the dust collector electrode is transferred to the recovery capacitor via the second current path. Since the second diode is connected to the second current path, the charge accumulated in the recovery capacitor does not flow back toward the dust collector electrode.

The switching means for current is put into a neutral state in a period in which no current flows in the first current path. Thereafter, the gap of the contact forming the first conduction state is opened until the possibility of re-ignition is eliminated, and when the switching means for current is brought into the second conduction state, the charge accumulated in the recovery capacitor is accumulated via the third current path. Return to the capacitor Since the third diode is connected to the third current path, the charge returned to the accumulation capacitor does not flow back to the recovery capacitor.

According to another aspect of the present invention, an input terminal to which a DC voltage is applied, an output terminal to which a dust collector electrode is connected, a storage capacitor having a ground potential at one electrode and the other electrode connected to the input terminal; And a recovery capacitor having a ground potential applied to one electrode, a series circuit of a switch means, a first inductor, and a first diode, the first current connecting the non-grounded electrode of the storage capacitor and the output terminal. And a series circuit of a second inductor and a second diode, wherein the output terminal and the non-grounding electrode of the recovery capacitor are connected, and the polarity of the output terminal side electrode of the second diode is A circuit for an electrostatic precipitator having a second current path having a polarity opposite to that of a diode and an electrical resistance connected in parallel with the second diode is provided.

The accumulation capacitor is charged through the input terminal. When the switch means is closed, the charges charged in the accumulation capacitor move to the dust collector electrode connected to the output terminal via the first current path. The electric charge which flowed into the dust collector electrode is recovered to the recovery capacitor via the second current path without flowing back to the accumulation capacitor. The electric charge collected by the recovery capacitor leaks to the dust collector electrode little by little through electric resistance. This leakage current charges the dust collector capacitance and slowly raises the absolute value of the dust collector voltage. On the other hand, since corona discharge occurs in the dust collector electrode, the dust collector voltage becomes a voltage in which the leakage current and the krona current are balanced.

According to another aspect of the present invention, a DC power source in which a voltage output state and a non-output state are switched by an on-off control signal, a dust collector electrode having a ground potential at one electrode, and a ground potential at one electrode are given. The common capacitor, a storage capacitor in which the output voltage of the DC power supply is applied to the other electrode, a recovery capacitor in which the ground potential is applied to one electrode, and a current switching means having a common contact, a first contact, and a second contact; A first conduction state connecting the contact point and the first contact point, a second conduction state connecting the common contact point and the second contact point, and a neutral state not connecting the common contact point to any of the first and second contacts points; And the common contact includes the current switching means connected to the non-grounded electrode of the storage capacitor, a first inductor, a first diode, and a series circuit. A first current path connecting the ungrounded electrode of the dust collector electrode and a series circuit of the second inductor and the second diode, and connecting the ungrounded electrode of the dust collector electrode and the ungrounded electrode of the recovery capacitor, And a second current path having a polarity of the electrode of the dust collecting electrode side of the second diode having a polarity opposite to that of the first diode, and a series circuit of the third inductor and the third diode. A non-grounded electrode of the capacitor and the second contact, a third current path having a polarity opposite to that of the second diode, the polarity of the recovery capacitor side electrode of the third diode, and an output voltage of the DC power supply Is set to the non-output state, and the dust collector electrode, the storage capacitor and the first current are changed from the time when the switching means to the current is set to the first conducting state and the switching means to the current is made to the first conducting state. After about half a period of the LC resonance circuit resonance frequency formed by the resonant frequency has elapsed, the dust collector electrode, the recovery capacitor, and the second capacitor are changed from the time when the switching means to the current is neutral and the switching means to the rectification is neutral. After about half a period of the LC resonant circuit resonance frequency formed by the current path has elapsed, the control means for switching the current-switching means to the second conduction state over time and then the output voltage of the DC power supply to the output state. Electrostatic precipitator is provided.

1 is a graph showing a circuit configuration of an electrostatic precipitator circuit, a peripheral circuit thereof, and a precipitator electrode, and a time variation of a voltage of the electrostatic precipitator circuit according to the first embodiment;

2 is a diagram showing another configuration example of a switch in the circuit for electrostatic precipitator according to the first embodiment;

3 is a circuit configuration diagram of an electrostatic precipitator circuit, a peripheral circuit thereof, and a precipitator electrode according to a second embodiment;

4 is a view showing a part of the configuration of the electrostatic precipitator circuit according to the modification of the first and second embodiments;

Fig. 5 is a graph showing a circuit configuration of an electrostatic precipitator circuit and its peripheral circuit and a precipitator electrode according to the prior art, a graph showing the time variation of the voltage of the electrostatic precipitator circuit, and another example of the rotational spark gap portion of the electrostatic precipitator circuit. Shown,

6 is a diagram showing a circuit configuration of an electrostatic precipitator circuit, a peripheral circuit thereof, and a precipitator electrode according to the prior art.

* Description of the symbols for the main parts of the drawings *

20: rotating shaft 21: rod-shaped member

22: light shielding plate 23: rotation electrode position detection means

L: Inductor C: Capacitor

RSG: Rotating Sprocket Gap D: Diode

R: Resistance DC: DC Power

EP: Dust collector electrode S: Thyristor

CNT: Timing control means SW: Switch

PG: Electrostatic precipitator circuit RT: Rotating electrode

ST: stop electrode

Fig. 1A shows the circuit arrangement of the electrostatic precipitator circuit, its peripheral circuit and the precipitator electrode according to the first embodiment of the present invention. DC power supply DC is comprised by a transformer and the diode bridge connected to the secondary winding of a transformer. The primary winding of the transformer is connected to the AC power supply through thyristor S ₁ . Thyristor S ₁ is controlled by timing control means CNT. The positive pole of the DC power supply DC is grounded, and the negative pole is connected to the power input terminal Tin of the electric precipitator circuit PG through the inductor Li.

The dust collector electrode EP of the electrostatic precipitator is composed of electrodes facing each other, and a gas such as air to remove dust passes therebetween. One electrode (dust collecting electrode) of the dust collector electrode EP is grounded, and the other electrode (discharge electrode) is connected to the output terminal T _out of the electric dust collector circuit PG. The dust collector electrode EP has a capacitance C _EP .

The electrostatic precipitator circuit PG uses a current path connecting one of the storage capacitors C _S and the recovery capacitors C _R with one electrode grounded therebetween, and between these capacitors or between these capacitors and the output terminal T _out , respectively. It is configured to include.

The storage capacitor C _S is connected between the input terminal T _in and the ground line, and is charged by the DC voltage applied to the input terminal T _in . The non-grounded terminal of the storage capacitor C _S is connected to the movable contact To of the switch SW. The switch SW has two fixed contacts T ₁ and T ₂ capable of conducting with the movable contact To and is controlled by the timing control means CNT.

The fixed contact T ₁ of the switch SW is connected to the output terminal T _out through a series circuit of the inductor L ₁ and the diode D ₁ . The diode D ₁ has a forward direction in which a current flows from the output terminal T _out to the switch SW.

The output terminal T _out is connected to the non-grounded electrode of the recovery capacitor C _R through a series circuit of the inductor L ₂ and the diode D ₂ . The diode D ₂ has a forward direction in which a current flows from the recovery capacitor C _R to the output terminal T _out .

The non-pointed electrode of the recovery capacitor C _R is connected to the fixed contact T ₂ of the switch SW through a series circuit of the inductor L ₃ and the diode D ₃ . The diode D ₃ has a forward direction in which a current flows from the fixed contact T ₂ to the recovery capacitor C _R.

The non-grounded electrode of the storage capacitor C _S and the output terminal T _out are connected to the resistor R. The resistance value of the resistor R is about several tens of MΩ, and almost no current flows in the normal operating state. The interconnection point of the inductor L ₁ and the switch SW is grounded via the diode D ₄ . In the normal operating state, the diode D ₄ is not conducted because the interconnection point of the inductor L ₁ and the switch SW is a negative voltage.

When the switch SW is inserted into the fixed contact point T ₁ , an LC resonant circuit I ₁ composed of a storage capacitor C _S , an inductor L ₁ , and a dust collector electrode EP is formed, and the fixed contact point T ₂ is formed. ), LC resonant circuit (I ₃ ) consisting of recovery capacitor (C _R ), inductor (L ₃ ), and capacitor (C _R ) is formed. The LC resonant circuit I ₂ is formed by the dust collector electrode EP, the inductor L ₂ and the recovery capacitor C _R.

The accumulation capacitor C _S , the recovery capacitor C _R , and the dust collector electrode EP have almost the same capacitance. The inductance of the inductor L ₁ is selected such that, for example, the resonant frequency half period T ₁ of the LC resonant circuit I ₁ is about 10 Hz. In other words,

T ₁ = π (L ₁ C _S C _EP / (Cs + C _EP )) ^1/2 = about 10㎲

Is selected to be.

The inductance of the inductor L ₂ is selected such that, for example, the resonance frequency half period T ₂ of the LC resonant circuit I ₂ is about 100 Hz. In other words,

T ₂ = π (L ₂ C _EP C _R / (C _EP + C _R )) ^1/2 = about 10㎲

Is selected to be. In this case L ₂ is about 100 times L ₁ .

Next, the circuit operation of Fig. 1A will be described with reference to Fig. 1B.

FIG. 1B shows the voltage change over time of each capacitor of the electrostatic precipitator circuit PG of FIG. 1A and the ungrounded electrode of the precipitator electrode EP. The horizontal axis shows time, and the vertical axis shows negative voltage. Curves Vs, V _EP , and V _R denote voltages between the electrodes of the storage capacitor C _S , the dust collector electrode EP, and the recovery capacitor C _R , respectively.

Before the time t ₁ , the switch SW is in a non-transparent state. The accumulation capacitor C _S is charged up to the output voltage of the direct current power source DC, and becomes the initial value Vso of the voltage Vs. The absolute value of this voltage is sufficiently larger than the corona starting voltage of the dust collector electrode EP. At this time, negative charges are stored in the dust collector electrode EP by the operation until the time t ₁ . Since this negative charge is lost by the corona discharge, in the steady state, the voltage V _EP is almost the same as the corona starting voltage and becomes the initial value V _EPO .

When the voltage V _R becomes higher than the voltage V _EP (absolute value becomes small), the diode D ₂ conducts and a current flows from the recovery capacitor C _R to the dust collector electrode EP so that it is in a steady state. Therefore, the voltage V _R is slightly lower than the voltage V _EP (the absolute value is large) and becomes the initial value V _RO .

The timing control means CNT puts the thyristor S ₁ into the non-conductive state immediately before the time t ₁ .

At the time t ₁ , the switch SW of the timing control means CNT is put toward the fixed contact point T ₁ . An LC resonant circuit I ₁ is formed so that forward current of the diode D ₁ flows. In other words, the charges accumulated in the storage capacitor (C _S) flows into the dust collector electrode (EP). Therefore, the absolute value of the voltage Vs decreases and the absolute value of the voltage V _EP increases. Since the capacitance C _EP of the storage capacitor C _S and the dust collector electrode EP is almost the same, the amount of increase of the absolute value of the voltage V _EP is almost equal to the amount of decrease of the absolute value of the voltage Vs.

If there is no energy loss due to the electrical resistance, the absolute value of the voltage Vs is the voltage V _EP at the time t ₂ when the ring period T ₁ of the resonance frequency of the LC resonance circuit I ₁ has passed. Decreases to the initial value V _EP O, and the absolute value of the voltage V _EP increases to the initial value V _SO of the voltage Vs. At the time t ₂ , the current tries to flow back, but since the diode D ₁ is inserted, the reverse current does not flow.

When the absolute value of the voltage V _EP becomes larger than the absolute value of the voltage V _R , a portion of the negative charge accumulated in the dust collector electrode EP flows into the recovery capacitor C _R because the diode D ₂ conducts. . However, since approximately 10 times of the LC resonance circuit (I ₂₎ half period (T ₁₎ of the half period of the resonance frequency (T ₂₎ is (I ₁₎ to the LC resonant circuit, the resonance current is excited in the (I ₂₎ the LC resonance circuit is sufficiently long compared to the rise time of the time (T _1). Because of this change in time (t ₁ ~t ₂₎ voltage (V _EP) according to the current flowing (I ₂₎ to the LC resonant circuit, the period is extremely low.

After the time t ₂ , the current of the LC resonant circuit I ₁ does not flow, and the current flows only to the LC resonant circuit I ₂ . That is, the negative charge accumulated in the dust collector electrode EP moves to the recovery capacitor C _R. Thus, the absolute value of the voltage V _EP is reduced and the absolute value of the voltage V _R is increased. Since the capacitances of the dust collector electrode EP and the recovery capacitor C _R are almost the same, the amount of decrease of the absolute value of the voltage V _EP and the amount of increase of the absolute value of the voltage V _R become almost the same.

If there is no energy loss due to electrical resistance, a voltage (V _EP) the absolute value of the voltage (V _R) the initial value (V _RO) reduced to, and voltage (V _R) absolute value of the voltage (V _S) of the Increase to the initial value (V _SO ). When the half period T ₂ has elapsed and the time t ₃ is reached, since reverse bias occurs in the diode D ₂ , no current flows. At this point, the voltage (V _EP), so the absolute value decreases to the preset initial value of a value close to (V _EPO) (V _RO) and the pulse waveform fall of the voltage (V _EP) sharp, the base voltage is also flat ( flat).

After the time t ₂ , the timing control means CNT returns the switch SW to the neutral position. At this time, since almost no current flows through the switch SW, the switch SW can be easily turned off.

After the time t ₁ , since the thyristor S ₁ is in a non-conductive state, after the time t ₂ , the voltage V _S almost remains unchanged at the initial value V _EPO . After the time t ₃ , since the diodes D ₁ and D ₂ are both in a non-conducting state, the voltage V _EP and the voltage V _R maintain substantially constant values.

At time t ₄ , the timing control means CNT turns the switch SW toward the fixed contact point T ₂ . The LC resonant circuit I ₃ is formed so that the forward current of the diode D ₃ flows. In other words, the charge stored in the recovery capacitor C _R moves to the accumulation capacitor C _S. Thus, the absolute value of the voltage V _R decreases and the absolute value of the voltage V _S increases.

Since the capacitances of the storage capacitor C _S and the recovery capacitor C _R are almost the same, and the voltage V _S after the time t ₂ remains close to the initial value V _EPO , the loss due to the electrical resistance If absent, the absolute value of voltage V _R decreases to a value close to the initial value V _EPO . This value becomes the initial value (V _RO ) of the next pulse. The absolute value of the voltage V _S increases to almost the initial value V _SO .

After the time t ₁ , the absolute value of the voltage V _EP decreases little by little in accordance with the above-described voltage change by the inter-electrode corona discharge of the dust collector electrode EP. Therefore, when there is enough time from a time (t ₄ + t ₃₎ has elapsed, the voltage (V _EP) becomes approximately equal to the corona discharge starting voltage.

After the time t ₄ + t ₃ , the timing control means CNT puts the thyristor S ₁ in a conductive state. When the absolute value of the voltage V _S is lower than the initial value V _SO , the accumulation capacitor C _S is charged by the DC power supply DC, and the voltage V _S is restored to the initial value V _SO . . In this way, the voltages V _S , V _EP and V _R return to the same state as the time t ₁ .

The diode D ₄ shown in FIG. 1A prevents the accumulation capacitor C _S from being charged with reverse polarity due to an abnormal vibration when a spark occurs inside the dust collector electrode EP. The resistor R recovers the voltage V _EP to a normal base voltage within a few seconds after the spark is generated inside the dust collector electrode EP.

The voltage V _EP shown in FIG. 1B has a waveform in which a deceptive negative pulse voltage of time t _{1 to} t ₃ is superimposed on a DC base voltage almost equal to the corona discharge start voltage. That is, according to the first embodiment, it is possible to intermittently generate an almost ideal short pulse voltage in the pulse charged electrostatic precipitator.

FIG. 2 shows another configuration example of the switch SW of FIG. 1A.

2 (A) shows the case of using the rotary spark gap. The rotary spark gap RSG ₁ has four stop electrodes ST _{1 to} ST ₄ and two rotary electrodes RT ₁ and RT ₂ disposed at almost rectangular apex positions. The stop electrodes ST ₁ and ST ₂ are both connected to the contact point T _O of FIG. 1A, and the stop electrodes ST ₃ and ST ₄ are respectively fixed contacts of FIG. 1A. T ₁ ) and (T ₂ ). The two rotary electrodes RT ₁ and RT ₂ are connected to each other by a rod-shaped member 21 and electrically shorted, and a center thereof is attached to the rotation shaft 20. The rotation shaft 20 is disposed at the center of the rectangle having four stationary electrodes ST _{1 to} ST ₄ as a vertex.

When the rotary electrodes RT ₁ and RT ₂ approach the stationary electrode while rotating the circumference of the rotary shaft 20, a discharge is generated in the gap during this time, so that the electrodes become conductive. For example, when the rotary electrodes RT ₁ and RT ₂ approach the stop electrodes ST ₁ and ST ₃ , respectively, the contact T ₀ and the contact T _{1 become} conductive. This corresponds to a state in which the switch SW enters the fixed contact point T ₁ in FIG. 1A.

In this state, when the rotary electrodes RT ₁ and RT ₂ rotate clockwise to approach the stop electrodes ST ₄ and ST ₂ , the contact T ₀ and T _{2 become} conductive. This corresponds to a state in which the switch SW enters the fixed contact point T ₂ in FIG. 1A.

A fan-shaped light shielding plate 22 which is rotationally symmetrical with respect to the rotating side 20 is attached to the rod-shaped member 21. In the vicinity of the rotating shaft 20, a light source and a rotating electrode position detecting means 23 for receiving the light emitted from the light source to form and output a light detection signal are arranged. The light shielding plate 22 rotates together with the rotary electrodes RT ₁ , RT ₂ and the rod-shaped member 21 to shield the light path of the rotary electrode position detecting means 23.

The light blocking plate 22 is disposed so as to release the light blocking is after the Fig. 1 (B) shielding the optical path of the visual rotary electrode position detecting means (23) prior to (t _1), and the time (t ₁ + T _3). That is, the light shielding plate 22 has the optical path of the rotating electrode position detecting means 23 before the rotating electrodes RT ₁ and RT ₂ approach the stop electrodes ST ₁ and ST ₃ so that a spark is generated between the electrodes. Is blocked, and the light blocking is released after the rotation electrodes RT ₁ and ST ₂ approach the stop electrodes ST ₄ and ST ₂ by a time T ₃ from the time when the spark is generated.

The output signal of the rotating electrode position detecting means 23 is input to the timing control means CNT in Fig. 1A. The timing control means CNT makes the thyristor S ₁ in a non-conductive state during the period in which the optical path of the rotary electrode position detection means 23 is shielded.

FIG. 3 (A) shows a circuit configuration of the electrostatic precipitator circuit, its peripheral circuit and the precipitator electrode according to the second embodiment of the present invention, and FIG. 3 (B) shows the electrostatic precipitator circuit of FIG. 3 (A). The time variation of the ungrounded electrode voltage in each capacitor and dust collector of is shown.

The electrostatic precipitator circuit PG shown in FIG. 3 (A) removes the LC resonant circuit I _{3 of the} electrostatic precipitator circuit PG shown in FIG. 1A and replaces the diode D ₂ instead. The resistor R ₂ is connected in parallel to the circuit. Since there is no LC resonant circuit I ₃ , a rotating spark gap RSG ₂ having two stop electrodes is used instead of the switch SW of FIG. 1A. The rotary spark gap RSG ₂ has the same value as that except for the stop electrodes ST ₂ and ST _{4 of} the rotary spark gap RSG ₁ shown in FIG. _2A . Other configurations are the same as those of the electrostatic precipitator circuit shown in Fig. 1A.

Immediately after the time t ₁ of FIG. 3B, the period until the time t ₃ after the absolute value of the voltage V _EP becomes larger than the absolute value of the voltage V _R is the diode (A) of FIG. 3A. D ₂ ) is conducting. Therefore, in FIG. 3A, the voltages V _S , V _EP , and V _R are represented by the time (t _{1 to} t ₃ ) of FIG. 1B regardless of the presence or absence of the resistor R ₂ . The same change as the period of.

Corona of time (t ₃₎ Then, the diode (D ₂₎ when a reverse bias occurs across the resistance (R ₂₎ recovering capacitor (C _R) dust collector electrode (EP) and a negative charge from leaking into the little dust collector electrode (EP) of Consumed by discharge. The absolute value of the voltage (V _R) is gradually reduced. That is, after the voltage V _EP shows the short pulse waveform in the period corresponding to the time t _{1 to} t ₃ of FIG. 3B, the absolute values of the base voltages of the voltages V _R and V _EP are Slowly fall, this is the initial value of the next pulse (V _RO ), (V _EPO ).

When the electrostatic precipitator circuit PG shown in Fig. 3 is employed, the voltage generated at the precipitator electrode cannot be an ideal waveform in which short pulses are superimposed on the corona starting voltage. The call can be prevented.

In the above embodiment, the capacitances of the capacitors were made almost equal in order to make the change of the capacitor voltage almost equal when the charge was transferred between the storage capacitor C _S , the dust collector electrode EP, and the recovery capacitor C _R. The capacitance of the storage capacitor C _S , the dust collector electrode EP, and the recovery capacitor C _R should be set so as to decrease in this order. Since the charge accumulated in the storage capacitor C _S is transferred in the order of the dust collector electrode EP and the recovery capacitor C _R , the attenuation of the voltage can be compensated by setting the capacitance of each capacitor to be in the above relationship. . However, in the square t _{3 of} FIG. 1B, when | V _S || V _EP | becomes a negative charge from the accumulation capacitor C _S to the dust collector electrode EP, the time t It is preferable to set each capacitance so that it becomes | V _S || V _EP | in ₃ ).

Fig. 4A shows a part of the electrostatic precipitator circuit according to the modifications of the first and second embodiments. A resistor R ₃ is connected in series with the diode D ₄ , and the rest of the configuration is the same as in FIG. 1A or FIG. 3A. When the spark in the dust collector electrode (EP) caused accumulation capacitors accumulating electric charge, the switch (SW) of the (C _S) (the first embodiment) or the rotating spark gap _{(RGS. 2)} (second embodiment case), the inverter (L ₁ ), the diode D ₁ is discharged through the dust collector electrode EP. Since this discharge circuit has a capacitor and an inductor, the discharge current vibrates. Therefore, the accumulation capacitor C _S may be charged in reverse polarity. The diode D ₄ constitutes a bypass circuit so that the accumulation capacitor C _S is not charged in reverse polarity.

A diode-resistor inserted in series with the (D ₄₎ (R ₃₎ inhibits the growth of flowing a diode (D ₄₎ current. Resistance (R ₃₎ an increase in the current flowing through the diode (D ₄₎ is suppressed to reduce the heating value generated in the diode (D ₄₎ by. The resistance of the resistor R ₃ is, for example, about 10 to 100 Ω.

4A illustrates a case where a series circuit of a diode D ₄ and a resistor R ₃ is connected between an inductor L ₁ and a switch SW or a rotary spark gap RGS ₂ . The storage capacitor C _S side may be connected to other positions than L ₁ ).

For example, it may be connected between 4 as shown in (B), a diode (D ₄₎ and the ungrounded electrode and the ground potential of the storage capacitor (C _S) to a serial circuit of the resistor (R _3).

In the first and second embodiments, the case in which the half period T _{1 in} FIG. 1B is about 10 ms and T ₂ is about 100 ms is described, but other times may be used. However, long enough than the half period (T ₂₎ half period (T ₁₎ to a sufficiently high pulse voltage (V _EP), for example, it is preferably not less than 10 times. For example, when the capacitance of the storage capacitor C _S is about 0.9 to 1.1 times the capacitance of the dust collector electrode EP and the recovery capacitor C _R , the induction coefficient of the inductor L ₂ is set to the inductor L ₁ . It is better to use at least 10 times the induction coefficient.

If the time T ₁ is shortened to 0.1 ms and the time T ₂ is shortened to about 1 ms, long streamer corona is likely to occur at the dust collector electrode, and chemically active O radicals and OH radicals are generated in the collected gas. Easier These radicals oxidize SO ₂ in the gas to form H ₂ SO ₄ . NH ₃ may be injected into the dust collected to neutralize H ₂ SO ₄ to be recovered as (NH ₄ ) ₂ SO ₄ . In this way, relatively short pulse driving can be used as the desulfurization apparatus.

In addition, since H ₂ SO ₄ acts to lower the electrical resistance of the dust collected, reverse ionization by the high resistance dust film attached to the surface of the dust collector electrode can be suppressed.

Although the present invention has been described in accordance with the above embodiments, the present invention is not limited thereto. For example, it will be appointed to those skilled in the art that various changes, improvements, combinations, etc. are possible.

As described above, according to the present invention, the charge accumulated in the dust collector electrode is recovered to the recovery capacitor without being flowed back to the power source, whereby a short pulse voltage is applied to the dust collector electrode, and then a circuit for applying the pulse voltage can be easily opened. have. This makes it possible to apply a voltage having a waveform close to the abnormal waveform to the dust collector electrode.

Claims (11)

An input terminal to which a DC voltage is applied, An output terminal connected to the dust collector electrode, An accumulating capacitor, provided with one electrode at a ground potential, and the other electrode connected to the input terminal; A recovery capacitor in which a ground potential is given to one electrode; A current having a common contact, a first contact, and a second contact is a switching means, the first conducting state connecting the common contact and the first contact, and the second conducting state connecting the common contact and the second contact. And a switching means for switching to the current having a neutral state in which the common contact is not connected at any one of the first and second contacts, wherein the common contact is connected to a non-grounding electrode of the storage capacitor; A first current path comprising a series circuit of a first inductor and a first diode, the first current path connecting the first contact point and the output terminal; And a series circuit of a second inductor and a second diode, wherein the output terminal and the non-grounding electrode of the recovery capacitor are connected, and the polarity of the output terminal side of the second diode is the polarity of the first diode. With a second current having a polarity opposite to And a series circuit of a third inductor and a third diode, wherein the non-grounding electrode of the recovery capacitor and the second contact are connected, and the polarity of the recovery capacitor side electrode of the third diode is equal to that of the second diode. An electrostatic precipitator circuit comprising a third current path having a polarity opposite to that of the polarity. The electrostatic precipitator circuit according to claim 1, wherein an induction coefficient of the second inductor is 10 times or more of the first inductor induction coefficient. The method according to claim 1 or claim 2, wherein the current switching means are first and second stop electrodes connected to the first and second contacts, respectively; Third and fourth stop electrodes connected to the common contact point; And a rotating spark gap having a rotating electrode conducting between the first and third stop electrodes in a certain rotational position and conducting between the second and fourth stopping electrodes in a certain rotational position. Electrostatic precipitator circuit. The fourth current path according to any one of claims 1 to 3, further comprising a fourth current path connected between an interconnection point of the first current path and the first point or an ungrounded electrode of the storage capacitor and a ground potential. A fourth diode including a series circuit of a diode and a resistance element, and wherein the fourth diode is connected to a polarity through which current flows when the potential of the non-grounded electrode of the storage capacitor becomes reverse polarity to that of the DC voltage applied to the input terminal. An electrostatic precipitator circuit comprising: a four-current furnace. An input terminal to which a DC voltage is applied, An output terminal to which the dust collector electrode is connected, A storage capacitor, in which one electrode is given a ground potential, and the other electrode is connected to the input terminal; A recovery capacitor in which a ground potential is given to one electrode; A first current path comprising a series circuit of a switch electrode, a first inductor, and a first diode, and connecting the non-grounded electrode of the storage capacitor and the output terminal; And a series circuit of a second inductor and a second diode, wherein the output terminal and the non-grounded electrode of the recovery capacitor are connected, and the polarity of the output terminal side of the second diode is the polarity of the first diode. With a second current having a polarity opposite to And an electrical resistance connected in parallel with said second diode. The electrostatic precipitator circuit according to claim 5, wherein the induction coefficient of the second inductor is 10 times or more than the first inductor induction coefficient. The circuit for electrostatic precipitator according to claim 5 or 6, wherein the switch means is constituted by a rotary spark gap. 8. The third diode and the resistor according to any one of claims 5 to 7, wherein one end is connected to the first current path and the other end is connected to the ground potential at the storage capacitor rather than the first inductor. And a third current path having the third diode connected to a polarity through which the current flows when the potential of the storage capacitor ungrounded electrode becomes reverse polarity with a DC voltage applied to the input terminal. A circuit for an electric grounder, characterized in that. A DC power supply whose voltage output state and non-output state are switched by an on / off control signal, A dust collector electrode having a ground potential at one electrode, An accumulating capacitor in which a ground potential is given to one electrode and an output voltage of the DC power supply is given to the other electrode; A recovery capacitor in which a ground potential is given to one electrode; A means for switching to a current having a common contact, a first contact and a second contact, the first conducting state connecting the common contact and the first contact, the second conducting state connecting the common contact and the second contact, And a neutral state in which the common contact is not connected to any of the first and second contacts, wherein the common contact is switched to the current connected to the storage capacitor non-grounding electrode; A first current path comprising a series circuit of a first inductor and a first diode, and connecting the first contact point and the non-grounding electrode of the dust collector electrode; A series circuit of a second inductor and a second diode, the non-grounded electrode of the dust collector electrode and the non-grounded electrode of the recovery capacitor, A second current path having a polarity opposite to that of the first diode of the electrode of the folding electrode of the second diode; And a series circuit of a third inductor and a third diode, wherein the non-grounding electrode of the recovery capacitor and the second contact are connected, and the polarity of the recovery capacitor side electrode of the third diode is equal to that of the second diode. With a third current that is opposite to the polarity, After the output voltage of the DC power source is in a non-output state, the current collector electrode, the scale capacitor, and the first power source are set when the switching means for current is put into a first conducting state and the switching means for current is made into a first conducting state. The dust collector electrode, the recovery capacitor, and when the switching means for the current is made in a neutral state after about half a period of the LC resonance circuit resonance frequency formed by one current path, and the switching means for the current is made in a neutral state. After about half a period of the resonant frequency of the LC resonant circuit formed by the second current path, the control means for switching the current switching means to the second conduction state and the output voltage of the DC power source to the output state. Electrostatic precipitator, characterized in that provided. The method according to claim 9, wherein the current switching means First and second stop electrodes connected to the first and second contacts, respectively; Third and fourth stop electrodes connected to the common contact point; A rotating spring having a rotating electrode conducting between the first and third stop electrodes when the rotational angle from a reference position is in a certain range, and conducting between the second and fourth stopping electrodes when the rotational angle is in a different range; Consisting of large gaps, And a rotating electrode position detecting means for detecting a rotation angle from the reference position of the rotating electrode and sending a detection signal to the control means. The method according to claim 10, wherein the rotary electrode position detecting means, With a light source, An optical sensor receiving the light emitted from the light source and transmitting a light detection signal to the control means; And a light blocking plate attached to the rotating electrode to rotate together with the rotating electrode and shielding light emitted from the light source when the rotation angle of the rotating electrode is in a certain range.