SU904784A1 - Alternating voltage supply apparatus for electric filter - Google Patents

Description

The invention relates to the dry cleaning of polluted gases from dust in electrostatic precipitators used in various industries.

Power supply devices for electrostatic precipitators are known to have an asymmetric alternating voltage of 50 Hz, the use of which, unlike traditional power supply devices with a voltage of one polarity, when trapping a high impedance electrostatic powder, weakens the reverse corona. This is due to the fact that the dust layer is periodically discharged by a positive half-wave voltage. The ratio of the amplitudes of the positive and negative half-voltages is regulated depending on the conductivity of the dust layer on the collecting electrodes. For this purpose, a half-wave rectifier shunted by an adjustable resistance 1 is connected in series with the electrostatic precipitator in the secondary circuit of a high-voltage transformer.

The disadvantages of this device are frequent recharging of dust particles, which leads to a decrease in the efficiency of its deposition on the collecting electrodes, and the impossibility of ensuring the maximum average voltage of the floor in the electrostatic precipitator.

The closest technical solution to the present invention is a device containing high-voltage power sources, high-voltage switches connected in series with a high-voltage rectifier.

1E of a constant voltage source control unit 2.

The disadvantages of this device include the difficulties associated with the commutation of a constant high voltage. At the moment of switching When the voltage polarity changes, the electrostatic precipitator remains charged until the voltage of the preceding polarity is high. A source

20 power, thus, connects to the electrostatic precipitator if there is a potential on the latter, the sign of which is opposite to the potential sign on the power source. Therefore

25 when an electrostatic precipitator is connected to a power source, an electric discharge occurs in the switches, which deteriorates the operating conditions of the switch. In addition, since the electrostatic precipitator

Claims (2)

30 is the charged capacity, then at. Recharging this capacitance causes a surge of current in the supply network. Recharging the electrofilter also leads to an increase in the energy consumed by the electrostatic precipitator to compensate for the residual charge on the electrostatic precipitator. The purpose of the invention is to protect switches from spark discharges and to reduce energy consumption. This goal is achieved by the fact that, in an electric filter power supply device, alternating voltage containing high-voltage sources of different polarities, high-voltage switches and a switch control unit, a control bit connected to the control block is connected to the output terminals. A controlled bit device can be connected via active resistance to facilitate its operation. The use of a controlled discharge allows the removal of the residual charge from the electrostatic precipitator at the moment of switching the polarity of the supply voltage. As a result, the connection of a constant-voltage source occurs at a zero potential on the electrostatic precipitator, which provides a spark-free connection of the switch to the electrostatic precipitator. Removing the residual charge from the electrostatic precipitator also provides a reduction in current surges in the supply network and a reduction in electricity consumption, since in this case it is not necessary to carry out the neutralization of the residual charge when the electrostatic filter is recharged. The presence of active resistance in the circuit of the controlled arrester will facilitate its operation, since most of the energy during the discharge of the capacitance, the electrostatic precipitator will be released in the active resistance. The magnitude of the active resistance R is selected in order to ensure the correct operation of the arrester, as follows: o - k RH R; Cj (p is the capacitance of the electrostatic precipitator; R, is the resistance of the spark in the discharge. FIG. 1 is a schematic diagram of the power supply device of the electrostatic precipitator by alternating voltage in FIG. 2, the operation diagram of the switches and the discharge device. The power supply electrofilt contains sources 1 and 2 DC voltage of positive and negative polarity, respectively, high-voltage switches 3 and 4 liters connecting sources 1 and 2 to the electrostatic precipitator 5, An electrical circuit is connected to the output terminal b of the power supply device The second discharge element 7 and the resistor 8, the control of the switches 3 and 4, the element 7 is carried out from the control unit 9. I ... The electrostatic precipitator power supply device works as follows. The switch 3 connects the constant voltage source 1 to the electrostatic precipitator 5 and remains on until time t (Fig. 2.6). During all this time, the electrostatic precipitator 5 is at a positive potential (Fig. 2, a). At time t, the switch 3 is disconnected, its contacts start diverging, and a signal is sent from the control unit 9 to turn on the switch 4 and the discharge element 7 (Fig. 2.c, d). The discharge element 7 short-circuits the capacity of the electrostatic precipitator 5, and since Saff R t, the electrostatic precipitator 5 is quickly discharged and by the time tj t when the switch contacts 4 are closed, the electrostatic precipitator 5 is at zero potential. After switching on the source 2, the electrostatic precipitator 5 until the moment tj is under the voltage of negative polarity. Next, the contacts of the switch 4 and 6 tons of the control unit 9 are unwound; the device can be used in power supply units of electrostatic precipitators for cleaning waste gases with the third group dust (10 Ωm), in power engineering (thermal power plants), chemical industry, ferrous and nonferrous metallurgy, etc. the interior construction materials and other sectors of the national economy. The invention The power supply device of the electrostatic precipitator is an alternating voltage containing high voltage sources of different polarities, high voltage switches and a switch control unit, which, in order to protect the switches from sparkles and reduce the amount of energy lost, The output of the electrostatic precipitator power supply is connected to a controllable discharge element connected to the control unit. FIG. one ft) “I 1. t I ( fw Sources of information taken into account in the examination 1.Patent of Germany 1206397, cl. 12e5, published. 05.11.63. 2. USSR author's certificate number 418220, cl. B 05 B 5/08, 07/15/68.