Electrostatic Phenomenon – Electrostatic phenomena is used for separation of smoke and other particles from the gases coming out the chimneys of various factories. In these chimneys a wire gauze is fixed between two metallic plates which are grounded (fig. 15.10).
Wire gauze is highly charged with positive charges. By electrostatic induction. Negative charges are induced on the inner surface of the metal plates.
When the gas containing smoke and other particles passes through the space surrounding the positively charged wire gauze, a positive charge is produced on these particles. These positively charged smoke and other particles are attracted by the plate due to the presence of negative charges on its surface. These particles on reaching the plate are deposited there. Thus, the smoke and other particles are removed from the gas coming out of the chimney.
Electrostatic is also being used in applying paints on the surfaces of different articles. In automobile industry electro-painting has acquired the status of a standard technology (fig. 15.11). The body of the car is earthed. When the particles of paint emerge out of the nozzle of the spray machine, they acquire a positive charge. When these positively charged particles reach near the body of the car, they induce negative charge on its surface due to electrostatic induction.
These negative charges attract the incoming positively charged paint particles. Due to this force of attraction, a very firm coating of the paint is formed on the surface of the car. This method is very effective, efficient and cheap. It also requires less paint as compared to other methods. Hence, it is being used to provide paint coating on refrigerators, metallic furniture and other articles.