Dangers and Applications of Electrostatic Charging
Situations Where Electrostatic Charging is a Hazard
Electrostatic charging can be dangerous in certain real-world contexts because sparks from discharge may ignite flammable materials or damage sensitive components. Examples include:
Fuel tankers and aircraft refuelling: As fuel flows, friction causes charge to build up. A spark could ignite fuel vapour, so grounding chains are used to safely discharge the charge.
Operating theatres: Surgeons and staff may generate static on synthetic clothing or flooring. A discharge could ignite anaesthetic gases.
Electronic components: Microchips and integrated circuits are extremely sensitive. A small discharge from a charged human body can destroy them.
Use of Electrostatic Charging in an Electrostatic Precipitator
Electrostatic precipitators are used in factories and power stations to reduce air pollution. Their working principle:
Charging the particles: Smoke and dust particles in flue gases are passed through a region of negatively charged wires. The particles pick up negative charges.
Collecting the particles: These charged particles are then attracted to large positively charged plates.
Removal: The plates are periodically shaken or tapped so that the collected dust falls into hoppers for disposal.
Electrostatic charging principles can be applied in other contexts:
Photocopiers and laser printers- A drum is given an electrostatic charge. Light or a laser removes the charge in certain areas, and toner particles (which are charged) stick only to the charged regions, forming the image.
Paint spraying (electrostatic painting)– The paint droplets are given given a charge (e.g. negative), and the object to be painted is given the opposite charge. This makes the paint spread evenly, reducing waste and giving a smooth coat even on irregular surfaces.