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.
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