Electronic dust collector
|Electronic dust collector|
Usually, complex and cumbersome mechanical filters with low productivity are used to remove dust from the air.
It is possible to significantly increase productivity and reduce the size of air-cleaning units 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 two wire grids 2 and 3 are installed, which play 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 kV. The grid z has reliable electrical contact with the duct (grounded). The dust particles, 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 with respect to the first grid.
To remove coarse particles, an additional mechanical filter 4 is installed between the first and second filters. Purified clean air escapes from the opposite opening of the pipe, and dust is deposited on the bottom near the second filter.
The device of the electronic dust collector is simple, but requires a source of constant voltage of 5.2 kV. It can be assembled according to the proposed scheme (see Fig. 2). It is a mains rectifier consisting of a step-up transformer Tr1 and a rectifier with voltage doubled on diodes D1, D2 and capacitors C2, C3. The output current is limited to a human-safe value of 5 ma using current limiting resistors R1-R3, as well as additional winding III, transformer Tr1 (together with capacitor C1, it forms a ferroresonant stabilizing circuit). Its action is reduced to the fact that in case of exceeding the rectified current of more than 5 ma, the voltage at the terminals of winding II decreases.
Neon lamp L1 in this device plays the role of a signaling device of the magnitude of the rectified voltage. It turns on parallel to the resistor R1. Its resistance is chosen in such a way that when the voltage is rectified at 5.2 kV, the voltage drop across resistor R1 is about 100 V, that is, sufficient for igniting a neon lamp. As dust accumulates on the second grid, an increase in current consumption occurs, which leads to a decrease in the output voltage. Lamp L1 goes out, indicating that the dust collector requires cleaning.
Cleaning the device can only be done after turning off the power.
The rectifier of the dust collector uses silicon diode columns and high-voltage capacitors used in televisions. Transformer Tr1, in order to increase its electric strength, is filled with epoxy resin. As diodes D1 and D2, you can use silicon high-voltage rectifying columns D1006-D1008.