Electrostatic precipitators use high voltage to charge and collect small particles and droplets.  This method of filtration has several advantages such as constant flow, low pressure drop, and efficient filtration of sub-micron smoke and fumes.  Filters are washable, and are normally dip-cleaned. Maintenance schedules are dependent on the amount of solids collected, since liquids will drain by themselves.  

In days past, and before cartridge filtration had evolved, electrostatic precipitators were used for weld fume collection, since it was the best method of filtering the sub-micron dust. Nowadays, we mainly apply them to mist and oil smoke, except for a few special cases.  One such case is a company that manufactures special “nano-powders”, which are a uniform 0.003 microns in size (that is correct, 3.0 nanometers!)  This product is expensive, so a reliable, efficient process collector is needed to capture it.To our knowledge, no other technology exists to filter this material, but our electrostatic system has been on line for about 10 years now, and is still going strong! 

As stated above, nowadays, electrostatic systems are most often used to filter mist and oil smoke where we know the filters will drain.  This is where the system really shines.  One customer of ours has 15 units filtering mineral oil smoke on a 3-shift basis.  He drains over 1 gallon per week (per system) of collected oil, and has not had to service the filter cells for over 2 years!  Needless to say, everyone is pleased.

To sum it up, electrostatic precipitators fill a niche where high efficiency is needed to control submicron particles.