JPS6127636Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention particularly relates to a power supply device for an electrostatic precipitator using an intermittent charging method.

Generally, an electric precipitator supplies a high voltage to the discharge electrode of the dust collection electrode part to charge dust etc. in the gas.
This device removes dust from the gas by attaching the dust to a dust collecting electrode. In such an electrostatic precipitator, when a high voltage is supplied from the power supply to the discharge electrode as described above, if a negative DC high voltage is continuously supplied, for example, a reverse ionization phenomenon will occur and the dust collection efficiency will decrease. There was an inconvenience caused by the decline.

Therefore, in recent years, intermittent charging type electrostatic precipitators that have solved these problems have been used. This intermittent charging type electrostatic precipitator usually uses an AC power source with a commercial frequency such as 60Hz, as shown in Figure 1.
The thyristor circuit 1 is configured such that an alternating current power supply AC is input from the thyristor circuit 1 to a rectifier circuit 3 via a transformer 2. Furthermore, this rectifier circuit 3 is connected to a rectifier 3a such as a diode.
and a coil 3b, which rectifies the AC power source (for example, with a half-wave rectified waveform) and connects it to the discharge electrode 4a of the dust collection electrode section 4.
Enter. Dust and the like in the gas are charged by this discharge (corona discharge) of the discharge electrode 4a. This dust and the like will adhere to the grounded dust collecting electrode 4b. The operation of the thyristor circuit 1 is controlled by the intermittent charging signal a from the control circuit 5, that is, the firing is controlled intermittently. A detection signal b is inputted to the control circuit 5 from the voltage detection circuit 6, and the level of the ignition control pulse, which is the intermittent charging signal a, is controlled in accordance with the signal b. This voltage detection circuit 6 detects the voltage of the AC power supply output to the secondary side of the transformer 2 in order to detect the discharge state of the discharge electrode 4a.

In this way, in an electrostatic precipitator, when an intermittent charging signal a as shown in FIG _. 2A is input from the control circuit 5 to the thyristor circuit ₁ , the signal a is The thyristor circuit 1 is controlled to fire intermittently. In addition, Figure 2A
The voltages V ₁ and V ₂ shown in are set by the detection signal b of the voltage detection circuit 6, etc., as described above. Therefore, the alternating current power supply AC is rectified only for a certain period of time at a certain period, and is supplied to the discharge electrode 4a of the dust collection electrode section 4.
, and intermittent charging will be performed. Therefore, occurrence of the above-mentioned reverse ionization phenomenon etc. can be prevented, and dust etc. can be separated and removed from the gas with high dust collection efficiency.

However, in the above-mentioned electrostatic precipitator,
Intermittent charging signal a of control circuit 5 (shown in FIG. 2A)
The timing of the rising period T ₁ and falling period T ₂ of is usually not synchronized with the AC power supply AC, so
As shown in FIG. 2B, the number of firings of the thyristor circuit 1 during period _T1 cannot be made constant.
Therefore, the number of peaks of the current waveform (for example, a half-wave rectified waveform) supplied to the dust collection electrode part 4 during the period _T1 of the intermittent charging signal a becomes an even number, an odd number, etc. . Further, since it is very difficult to accurately set the period T ₁ and period T ₂ of the intermittent charging signal a, it is impossible to accurately perform intermittent charging at a constant cycle. Therefore, positive or negative alternating current power is supplied to the primary side of the transformer in an unsteady manner, which adversely affects the entire device, such as the occurrence of biased excitation. In addition, since it is not possible to obtain regular periodic current and voltage, when the precipitator is operated, it is difficult to display the current and voltage with conventional indicators, making it difficult to grasp the operating status of the precipitator. There is.

This idea was made in view of the above circumstances, and is controlled by an intermittent charging signal to supply an AC power supply of a predetermined frequency to the dust collecting electrode section through a transformer and a rectifier only at a fixed period and for a fixed period of time. In a power supply device for an intermittent charging type electrostatic precipitator, the power supply device comprises a pulse generating means for generating a pulse signal synchronized with the AC power source, and a period setting circuit for setting a rising period and a falling period of the intermittent charging signal. , counts the pulse signals from the pulse generating means according to the setting value of the period setting circuit, and generates an intermittent charging signal having a rising period of an integral multiple of 1/2 and a falling period of an integral multiple of 1/2. The main purpose of the electrostatic precipitator is to improve the reliability of the electrostatic precipitator by preventing the occurrence of uneven excitation of the transformer and accurately performing intermittent charging at a constant cycle. An object of the present invention is to provide a power supply device for an electrostatic precipitator that allows easy understanding of the operating status when the device is operated.

An embodiment of this invention will be described below with reference to the drawings. FIG. 3 shows the configuration of the electrostatic precipitator according to this invention, and 7 is a periodic signal generating circuit (hereinafter referred to as a synchronous circuit). This synchronous circuit 7 inputs a rectified signal c to the control circuit 5 according to the input AC power supply AC. In response to this adjustment signal c, an intermittent charging signal a synchronized with the alternating current power source AC is input from the control circuit 5 to the thyristor circuit 1.

Specifically, such a synchronization circuit 7 is constructed as shown in FIG. That is, AC power supply AC
A first waveform shaping circuit 8 is provided which outputs a trigger signal t in response to zero displacement of the AC waveform as shown in FIG. This trigger signal t is shaped into a square wave pulse signal p by a second waveform shaping circuit 9 and inputted to a counter 10. The counter 10 counts the pulse signal p according to the signal s from the setting circuit 11 during the period T ₂ and inputs the adjustment signal c, which is its output signal, to the control circuit 5 . From this control circuit 5, for example, a counter 10 outputs m times in a period _T1 .
By counting the pulse signal p 2n times at _T2 , an intermittent charging signal a synchronized with AC as shown in FIG. 5 is output. In this case, the period of signal a
T ₁ and T ₂ are as follows: T ₁ = m×1/2 (1) T ₂ = n×1/ (2) where m, n: positive integer: AC frequency. In addition, other configurations of the electrostatic precipitator are the same as the above-mentioned No. 1.
Since it is the same as the figure, the same reference numerals are given and the explanation is omitted.

In such an electrostatic precipitator, when an AC power supply AC having a commercial frequency such as 60 Hz (shown in FIG. 6A) is turned on, the synchronous circuit 7 as described above is activated.
As a result of this operation, an intermittent charging signal a synchronized with an AC waveform as shown in FIG. 6B is input from the control circuit 5 to the thyristor circuit 1. When the intermittent charging signal a is input to the gate of this thyristor circuit 1, the firing timing is as shown in FIG. 6C,
Depending on the timing of this ignition control, the AC power supply
is input to the primary side of transformer 2. Then, the alternating current power AC is input from the secondary side of the transformer 2 to the rectifier circuit 3, and as a result, the output from the rectifier circuit 3 is shown in FIG. 6D.
A power source such as a half-wave rectifier as shown in the figure is connected to the dust collecting electrode section 4.
is input to the discharge electrode 4a. Due to the discharge (corona discharge) of the discharge electrode 4a, dust particles in the gas are charged and adhere to the dust collection electrode 4b, and the dust particles are separated and removed from the gas. Note that the operation of the voltage detection circuit 6 is similar to that shown in FIG. 1 above, so a description thereof will be omitted.

In this way, the dust collection electrode section 4 can be charged intermittently in accordance with the intermittent charging signal a from the control circuit 5, so that dust and the like can be separated and removed from the gas with high dust collection efficiency. Furthermore, in this case, the intermittent charging signal a can be adjusted for a period of time by adjusting the synchronizing signal 7.
T ₁ and T ₂ are set as shown in equations (1) and (2) above, and are power supply AC synchronization signals synchronized with zero displacement of the AC power supply AC. Therefore, the period T ₂ of the intermittent charging signal a is necessarily equal to the cycle 1/of the power supply AC.
The power supply during period T ₁ is set to an integer multiple of
Regardless of whether the number of peaks in the AC waveform is odd or even, the positive and negative voltages applied to the transformer 2 are symmetrical, and the occurrence of biased excitation of the transformer 2 can be prevented. Also,
Since the periods T ₁ and T ₂ of the intermittent charging signal a can be easily set as described above, intermittent charging with a constant period can be performed accurately. Therefore, when operating an electrostatic precipitator, it is possible to obtain current and voltage with a constant period. For example, if the period T ₂ is within a practical range (9 x 1 / or less), conventional instructions can be used. The meter needle no longer vibrates, making it easier to display current and voltage.

As detailed above, according to this invention, AC power at a predetermined frequency is supplied to the dust collecting electrode section via the transformer and rectifier at a fixed period and only for a fixed period of time under the control of an intermittent charging signal. A power supply device for an intermittent charging type electrostatic precipitator, comprising: a pulse generating means for generating a pulse signal synchronized with the AC power source; a period setting circuit for setting a rising period and a falling period of the intermittent charging signal; and a period setting circuit for setting a rising period and a falling period of the intermittent charging signal. means for counting pulse signals from the pulse generating means according to a setting value of the setting circuit and generating an intermittent charging signal having a rising period of an integral multiple of 1/2 and a falling period of an integral multiple of 1/2; Since the present invention is equipped with the above, it is possible to prevent the occurrence of biased excitation of the transformer, and to perform intermittent charging at a constant period accurately and easily. Therefore, it is possible to improve the overall reliability of the electrostatic precipitator, and to display the current and voltage in an intermittent charging state without using special means to understand the operating status when the electrostatic precipitator is operated. This can be easily done using an indicator or the like.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of a conventional electrostatic precipitator, Fig. 2 A and B are timing charts explaining its operation, and Fig. 3 is a schematic diagram of an electrostatic precipitator according to an embodiment of the present invention. FIG. 4 is a specific configuration diagram of a synchronization signal generation circuit according to an embodiment of this invention, and FIG.
The figure is a timing chart illustrating its operation, and FIG. 6 is a timing chart illustrating the operation of an electrostatic precipitator according to an embodiment of this invention. 1... Thyristor circuit, 2... Transformer, 3...
Rectifier circuit, 4... Dust collection electrode section, 3a... Diode, 3b... Coil, 4a... Discharge electrode, 4b...
...dust collection electrode.

Claims (1)

[Scope of Claim for Utility Model Registration] An intermittent charging method that is controlled by an intermittent charging signal and supplies AC power at a predetermined frequency to the dust collecting electrode part through a transformer and a rectifier only at a certain period and for a certain period of time. In a power supply device for an electrostatic precipitator, a pulse generating means for generating a pulse signal synchronized with the AC power supply, a period setting circuit for setting a rising period and a falling period of the intermittent charging signal, and a setting of the period setting circuit. and means for counting pulse signals from the pulse generating means according to the value, and generating an intermittent charging signal having a rising period of an integral multiple of 1/2 and a falling period of an integral multiple of 1/2. Characteristic electric precipitator power supply device.