JPS6136467B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to an electrostatic precipitator.

The conventional intermittent charging circuit for this type of device has a thyristor control circuit A as shown in the block diagram of FIG.
Thyristor B is intermittently fired by supplying an intermittent charging signal as shown in FIG. The dust collection electrode E is intermittently charged via the rectifier D.

However, in such a circuit, FIG.
Since the timing of T ₁ and T ₂ is not synchronized with the AC power supply, the charging time T ₁ depends on the settings of T ₁ and T ₂ .
As shown in Fig. 2B, the number of peaks of the charging current supplied to the dust collection electrode E during _T1 may be an even number or an odd number. As a result, a bias excitation phenomenon occurs in the transformer C, making it extremely difficult to set accurate times T ₁ and T ₂ , making it impossible to obtain a constant charging voltage and current, and using conventional indicators. However, it is difficult to display accurate operating conditions, and this is a problem in terms of reliability, high efficiency, and stability.

The present invention has been proposed in view of the above circumstances, and is an electrical system that improves reliability, high efficiency and stability, and makes it easy to set charging time and charging stop time, and to understand the operating status of charging voltage and current. For the purpose of providing a dust collector, a current control element such as a thyristor is controlled by an intermittent charging signal to intermittently obtain a DC high voltage from a power supply with a commercial frequency f, and apply this to a dust collection electrode. In electrostatic precipitators, intermittent charging time T ₁ synchronized with commercial frequency power supply
=1/f and an intermittent charging stop time T ₂ =nT ₁ (n is an integer).

An embodiment of the present invention will be explained with reference to the drawings.
Figure 3 is a block diagram showing the circuit, Figure 4 is an output waveform diagram of each part in Figure 3, Figure 5 is an enlarged view of the synchronizing signal generation circuit in Figure 3, and Figure 6 is the same as in Figure 5. It is an output waveform diagram of each part.

In the above figure, the same reference numerals as in FIG. 1 indicate the same members as in the same figure, and G is a synchronizing signal generation circuit inserted between the AC power source and the thyristor control device A, and the waveform shaping circuit G ₁ , G ₂ , counter G ₃ , T ₂
Consists of setting circuit _G4 .

In such a circuit, the waveform shaping circuit G ₁ generates an AC power supply waveform (a trigger signal at phase θ=0 in Figure 6B) as shown in Figure 6B, and the waveform shaping circuit G ₂ generates a trigger signal at phase θ = 0 in Figure 6B. As shown in Figure D, an intermittent charging signal D synchronized with the power supply is obtained by making a square wave pulse and counting this pulse with a counter _G3.Here , the setting circuit _G4 is configured to set the charging time T as shown in Figure D. ₁ = 1/f and a charging stop time T ₂ = nT ₁ (n is an integer) is set to output an intermittent charging signal D.

Therefore, in Fig. 3, when the intermittent charging signal (B in the figure) output from the thyristor control circuit A enters the gate of the thyristor B, the firing timing of the thyristor B becomes as shown in C in the figure, and the dust collecting electrode The current flowing through E becomes a current with a constant number of peaks as shown in D in the figure.

In the above embodiment, by fixing the charging time T ₁ = 1/f, the number of current peaks during the charging time T ₁ is two, and the charging stop time T ₂ is also an integral multiple of the power frequency, and the dust collecting electrode The intermittent charging is completely synchronized with the power supply.

As a result, alternating current will always flow through transformer C, eliminating the possibility of biased excitation, making it easier to set T ₂ , and since voltage and current flow at a constant cycle, T ₂ will be short. In other words, when the value is about 1/f or less and is close to the practical setting value, the indicator needle will not vibrate, and the use of the conventional indicator will not cause any practical problems.

In short, according to the present invention, an electrostatic precipitator is configured to control a current control element such as a thyristor using an intermittent charging signal to intermittently obtain a high DC voltage from a power source at a commercial frequency f and apply this to a precipitating electrode. , the intermittent charging time T ₁ synchronized with the commercial frequency power supply
By providing a synchronizing signal generation circuit for setting = 1/f and intermittent charging stop time T ₂ = nT ₁ (n is an integer), an electrostatic precipitator with improved performance is obtained.
The present invention is extremely useful industrially.

[Brief explanation of the drawing]

Fig. 1 is an intermittent charging circuit diagram of a known electrostatic precipitator, Fig. 2 is an output waveform diagram of each part of Fig. 1, Fig. 3 is a block diagram showing an embodiment of the present invention, and Fig. 4 is a diagram. FIG. 5 is an enlarged view of the synchronizing signal generation circuit of FIG. 3, and FIG. 6 is an output waveform diagram of each part of FIG. 5. A... Thyristor control circuit, B... Thyristor, C
...Transformer, D...Rectifier, E...Pullifier electrode, F...Branch circuit, G...Synchronizing signal generation circuit, _G1 , _G2 ...Waveform shaping circuit, _G3 ...Counter, _G4 ... _T2 setting circuit, T ₁ ...
Charging time, T ₂ ...Charging stop time, f...Commercial frequency.

Claims (1)

[Scope of Claims] 1. An electrostatic precipitator in which a current control element such as a thyristor is controlled by an intermittent charging signal to intermittently obtain a high DC voltage from a power source at a commercial frequency f and apply this to a precipitating electrode. An electrostatic precipitator comprising a synchronization signal generation circuit for setting an intermittent charging time T ₁ =1/f and an intermittent charging stop time T ₂ =nT ₁ (n is an integer) synchronized with a commercial frequency power source. Device.