Electronic dust collector
|Electronic dust collector|
Usually, complex and cumbersome mechanical filters having low productivity are used to purify air from dust.
It is possible to increase the productivity and reduce the dimensions of the air purifying plants by using an electronic dust collector.
The principle of operation of such a dust collector is that the polluted air passes through a metal pipe 1, inside which are installed two wire grids 2 and 3, playing the role of a filter (Fig. 1).
Grid 2 is isolated from the box and is in relation to it under a constant positive voltage of 5.2 square meters. Grid z has a reliable electrical contact with the box (grounded). Particles of dust, passing through the first grid, acquire a strong electric charge, which causes them to settle on the grid of the second filter, which has a negative potential in relation to the first grid.
For cleaning large particles, an additional mechanical filter 4 is installed between the first and second filters. The dust-free clean air exits from the opposite hole in the tube, and the dust settles on the bottom near the second filter.
The device of an electronic dust collector is simple, but requires a constant voltage source of 5.2 square meters. It can be assembled according to the proposed scheme (see Figure 2). It is a rectifier of mains voltage, consisting of a step-up transformer Tp1 and a rectifier with a voltage doubling on diodes D1, D2 and capacitors C2, C3. Limitation of the output current to a safe value for a person of 5 mA is carried out by means of current-limiting resistors R1-R3, as well as an additional winding III, of the transformer Tr1 (together with the capacitor C1, it forms a ferroresonance stabilizing circuit). Its effect is that if the rectified current exceeds 5 mA, the voltage at the terminals of the winding II decreases.
The neon lamp L1 in this device plays the role of an indicator of the magnitude of the rectified voltage. It is connected in parallel with the resistor R1. Its resistance was chosen so that when the rectified voltage is 5.2 kV, the voltage drop across the resistor R1 is about 100 V, that is, sufficient to ignite the neon lamp. As dust accumulates on the second grid, there is an increase in the current consumed, this leads to a decrease in the output voltage. L1 lamp goes out, indicating that the dust collector needs cleaning.
You can only clean the device after turning off the power.
In the rectifier of the dust collector, silicon diode poles and high-voltage capacitors used in televisions are used. Transformer Тр1, with the purpose of increasing its electrical strength, is filled with epoxy resin. As diodes D1 and D2, you can use silicon high-voltage rectifier poles D1006-D1008.