Electrostatic Precipitation (ESP)

[DanHalen]

Hello I really like the forum here, and apologies for any redundancy in previous threads. I didn't find any answers in recently posted threads and didn't want to bump a thread that was too old.

 

I'm looking for a simple way to make a small electrostatic precipitator for use in a small enclosed box by giving a plate or interior of the box an electrostatic charge strong enough to hold on to dust-like particles of a relatively large size as far as particles go, about the size as some of the larger particles in household dust but with a little more density.

 

From what I perhaps incorrectly understand, metals aren't suitable for this purpose because of their conductivity. I am also aware of the obvious solution of rubbing a piece of fur or carpet on the surface, but I'm curious about automating and if possible maybe even adjusting the intensity of the electrostatic charge on the plate.

 

If anyone could help point me in the right direction, give me some tips on how to start, if this is even something that can be accomplished in an economic manner, I'd be very willing and happy to document its construction in this thread as a demonstration to others who, like me, are interested and less knowledgeable in this area.

 

Thanks!

[dirtyamerica]

I'm just guessing here but if you're looking for economy, using a cheap air filter will probably be more cost effective than building and paying for the electricity to run an ESP in your house.

 

I can only speak about ESP's based on my knowledge/experience of this application in the industrial setting where huge amounts of airflow would seriously be disrupted by a filter...along with other logistics.

 

Essentially, an ESP contains two types of plates: Discharge Electrodes, which give a charge to the airborne particulates and Collecting Electrodes, which attract the particulates via an oppositely charged static electrical force. The amperage through all of these electrodes are comparitively small compared to the voltage (read: static electricity). Once the particulates are collected on the proper electrode plates, they can be "rapped" off by automated hammers. The clumps of particulates fall to collection hoppers and are disposed of by other systems.

 

I've seen a commercial on tv once about a small, home unit that does the same thing except you have to turn it off and wipe the collecting electrodes off with a rag every so often.

 

I guess if you really wanted to impress your visitors you could follow an ESP up with a wet scrubber system, lol.

[1bobwhite]

DanHalen,

 

Just run the air past your computer intake fan and the crt monitor screen. They should clean up the air pretty good by the way they collect all the dirt.

 

Electrostatic air cleaners are used throughout industry and can do a fantastic job. They all have maintenance to be done. Someone has to clean them from time to time.

Metal plates may be used no problem, just keep them statically charged to one of the polarities. Make arrangements to momentarily reverse the polarities, or mechanically rap the plates, and the dirt will fall off to the bottom. Some of the dirt will not fall off because it is mixed with cooking oils and other aerosols that have precipitated onto the plates, and this will have to be washed off during your maintenance.

 

One cheap way from the old days of crt monitors, and still from cheap old tv's is to use the chassis with the flyback transformer circuit attached to the metal plates instead of the tube. Put the B+ on one plate, and the chassis ground to the other plate.

 

B+ averaged around 25,000 volts, and could deliver a nasty zap, so be careful.

 

Believe it or not but water droplets may be statically charged and attract particles, but you said cheap, and these aren't that, unless you want to construct one of Lord Kelvins thunderstorm chambers at home. It can be done, just Google Lord Kelvin's thunderstorm and check it out.

 

Good luck,

Bob.