The Electrostatic Precipitator
The electrostatic precipitator is a device fitted to factory and power station chimneys to collect dust that would otherwise escape into the atmosphere as pollution. It consists of oppositely charge plates, over which waste gases containing pollutants and dust pass.
The gases pass through a negatively charged metal grid, becoming negatively charged. As the gases are blown over positively charged plates attached to the chimney wall, they are attracted to the plates. When they make contact with the plates, they become neutralised and may fall into dust collecting fittings. The collecting plates are anyway shaken periodically to remove dust. The gas that enters the atmosphere is then free of dust.