working of electrostatic precipitator

Electrostatic precipitator is a device consisting of discharged wires and collecting plates which are used for removing the dust and smoke particles from air. 

This is done by applying high voltage electrostatic field. High voltage is supplied to the discharged wires which creates an electrostatic field between the wires and the collecting plate resulting in the ionization of the gas. The dust particles combine with the high amount of electrons and ions already present in the ionized gas. This combination leads to the polarization of the dust particles (most of the dust particles become negatively charged). Electrostatic forces are then applied to the present gas which migrates the negatively charged particles towards the positive electrode and get accumulated on the collecting plate. When the collection reaches a certain thickness on the plate, rapping system starts to work removing the particles from the collection plate with the help of vibration. These particles then fall into the hopper, ending the process of collection.