SU1556757A1 - Apparatus for applying electric precipitator for gas cleaning with alternate voltage - Google Patents

Abstract

The invention relates to the electrical purification of gases in electrostatic precipitators (ESP) and makes it possible to increase the reliability of operation of the ESP. The ESP power source contains a thyristor controller 2, a high-voltage transformer 3 with a current sensor 4 in the high-voltage winding, an alternating voltage driver 5, a voltage sensor 6, a controller 7, a control unit 8 and a driver of 9 pulses, a separation unit 10, integrators 11, 12 voltages of positive and negative polarity with zero-feedback keys 13, 14, threshold elements / PE / 5, 16, OR 17 logic element, executive unit / IB / 18 of the 20-line electrode electrodes and indicator 19. Voltage proportion The total voltage on the ESP is supplied from sensors 6 to block 10, where it is divided into two channels. Signals of positive and negative polarities from the outputs of block 10 are fed to the integrators 11, 12 and the keys 13, 14. When the voltage of both polarities is formed on the EF, the integrators 11 and 12 alternately zeroate. From their conclusions, signals are fed to the inputs of PE 15 and 16, whose outputs through the OR element 17 are fed to input of IB 18. If both polarities are present, PE 15, 16 does not work, and IB 18 does not work. When one of the polarities disappears, P 15 or 16 and through the element OR 17 IB 18. The signal from IB 18 output includes the opening mechanism 20 and the indicator 19. From the other PE output 15 or 16, the signal about the disappearance of the voltage of one of the polarities is sent to the control unit 8 and the ESP passes unipolar power supply. 3 il.

Description

This invention relates to the electrical purification of gases in electrostatic precipitators, in particular to the purification of gases by alternating voltage.

The purpose of the invention is to increase the reliability of the device.

FIG. 1 depicts functional

scheme of the proposed device; in fig. 2 - timing diagrams for the operation of the device; in fig. 3 - timing diagrams explaining the operation of the control system in case of disappearance of one of the voltage polarities.

The power supply device of the electrostatic precipitator 1, with alternating voltage, contains a thyristor regulator 2, a high-voltage transformer 3, in the high-voltage winding of which the Current sensor 4 is turned on, an alternating voltage driver 5, an alternating voltage sensor 6, a regulator 7, a control unit 8, a pulse driver 9 , the polarity separation unit 10, the integrators 11 and 12 of the voltage of positive and negative polarity, respectively, the keys 13 and 14 of resetting the integrators, the threshold elements 15 and 16, the logical element OR 17, the executive unit 18, the indicator 19 and the electrode removal mechanism 20.

The alternating voltage driver 5 may consist of a diode bridge, the diagonal of which includes a high-voltage thyristor switch.

The device works as follows.

The control and regulation system consisting of blocks 7-9 generates signals to thyristor controller 2 and shaper 5 alternating voltage according to a given program, as a result of which alternating voltage is formed on the electrostatic precipitator, depending on the technological features of each specific dust and the design of the electrostatic precipitator, the duration and amplitude of each polarity of the voltage may differ.

From the voltage sensor 6, a voltage proportional to the voltage on the electrostatic precipitator is fed to the input of the polarity separation unit 10, in which the input signal is limited to a certain level and separated in two channels (positive and negative polarity). The limit level corresponds to the minimum operating voltage on the electro-filter.

The positive and negative polarity signals from the outputs of block 10 are fed to the inputs of the integrators I and 12 of the voltage of the respective polarities and controlled keys 13 and 14. The signal of positive polarity from the output of the block 10 includes a key 14 installed parallel to the integrator 12 of the negative field and nulls it, and the negative polarity signal includes a key 13 connected in parallel with the integrator 11 of the positive polarity channel and also null it. During normal operation of the device, when the voltage of both polarities is formed on the electrostatic precipitator, the integrators 11 and

with. 12, corresponding to the time to-t in FIG. 2

The constant times of the integrators are chosen such that the voltage at their outputs in the normal operating mode at the maximum operating duration of any voltage pitch on the electrostatic precipitator 1 does not exceed the threshold voltage, (/ op, at which threshold elements 15 and 16 are turned on .

The signals from the outputs of the integrators AND and 12 are fed to the inputs of the threshold elements 15 and 16, the outputs of which through the logic element OR 17 are fed to the input of the execution unit 18. In the presence of both polarities of the voltage supplying the electrostatic filter, the threshold elements 15 and 16 are not

0 is triggered, therefore, the execution unit 18 does not trigger, as a result of which there are no signals.

When a negative polarity voltage disappears on an electrostatic precipitator, the positive polarity voltage is formed in accordance with a given program, and from the time /: to h the positive polarity voltage on the electrostatic precipitator decreases exponentially with a constant

The change corresponds to the constant time of discharge of the electrostatic filter's own capacity through a voltage divider and active leaks. This voltage may decrease below the voltage of the beginning of the corona in the discharge gap of the electrostatic precipitator, as a result of which the efficiency of dust collection decreases sharply.

Since at time t there is no signal at the output of block 10 via the negative polarity channel, the key 13 does not work and the integrator 11 of the positive polarity channel does not zero, and the voltage at its output and input of the threshold element 15 continues to increase linearly.

At time tz, control unit 8 generates a signal for the formation of a positive polarity voltage and the positive polarity channel functions as described above.

At the moment F, the voltage at the input of the threshold element 15 reaches the threshold value Un0p, as a result of which the threshold element 15 and the executive unit 18 are triggered via the OR element 17. The response time tz of the threshold element 15 and the executive unit 18 depends on the setting of the integrator and the duration of application the voltage from the output of the block 10.

The signal from the output of the actuator unit 18 is applied to turn on the electrode extraction unit 20 and the indicator 19.

From another output of the threshold element 15, the signal on the disappearance of the negative polarity voltage enters the control unit 8, in which the channel of the control pulses of the negative polarity formation is blocked, as a result of which the electrostatic precipitator switches to a single-polar voltage.

When the positive polarity disappears, the device operates in the same way.

The economic effect from the introduction of the proposed device is due to the prevention of possible emergencies on the electrostatic precipitator when the voltage of one of the polarities disappears, which can be caused by simultaneous shedding of large volumes and masses of collected dust leading to the heaps of the hydraulic ash dumping bins, as well as an increase in the degree of purification when switching the electrostatic precipitator into a unipolar dietary mode without voltage dips during the absence of polarity.

Claims (1)

Invention Formula A device for supplying an alternating voltage to a gas cleaning electrostatic precipitator containing a thyristor regulator whose input is connected to an alternating voltage network and the output to the primary winding 0 high-voltage transformer, the first output of the secondary winding of which is connected to the first input of an alternating voltage generator, and the second output of the secondary winding of a high-voltage transformer is connected to the common bus through the current sensor, the output of the current sensor is connected to the first input of the regulator, the output of which is connected to the first input - control unit, the output of which is connected to the input of the pulse former, the first 0 the course of which is connected to the control input of the thyristor controller, and the second. - to the second input of an alternating voltage driver, the output of which is connected to the first extreme terminal of the divider , - voltage, the second extreme terminal of which is connected to the common bus, and the middle point of the voltage divider is connected to the second input of the controller, characterized in that, in order to increase reliability, it is equipped with integrators of positive and negative polarity with zeroing keys feedback, two threshold elements, an OR element, an executive unit of the electrode extraction mechanism, an indicator and a polarity separation unit, the input of which is connected 5 to the midpoint of the voltage divider, and outputs to the integrator inputs of positive and negative polarity, respectively; the control input of the zero key of the integrator of positive polarity is connected to the integrator input negative polarity, and a negative polarity zero integrator control input is connected to the positive polarity integrator input, the output of which is connected via the first threshold 5 is the element to the second input of the control unit and to the first input of the OR element, and the output of the negative polarity integrator is connected through the second threshold element to the third input of the control unit and to the second input of the OR element, the output of which is connected 0 to the executive unit of the electrode extraction mechanism and the indicator. ffwxadJ BoixodS 8khod5 Exit out: 7) 5