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My Two DIY Electro-Static Precipitator (ESP) Designs

A project log for Household Electrically Enhanced Wet Scrubber

A household air purification unit for kitchens, labs, & smokers used to scrub fine particulates and VOC's out of the air.

Jimmy LockeJimmy Locke 10/20/2015 at 08:561 Comment

Tube ESP

As I yet again went back to the drawing board, I decided I would pursue a tried and true method in designing an electrostatic precipitator to deal with the sub micron particles along with any new design I'd come up with just in case the new idea didn't work as planned.

For my ionizing circuit, I was going to build a tube electrostatic precipitator that would either go before or after the wet scrubber as a separate stage. A tube electrostatic precipitator has a thin wire going axially through the center of a tube that is held at high voltage to produce corona that ionizes the air. Particulate laden air is passed through the tube and ionizes the particles such that it sticks to the walls of the tube.

Although I intended to do this originally but was stopped by the fact that these devices produce Ozone, I would make the design such that it would minimize Ozone production by using positive corona and then absorb any produced Ozone into the scrubbing liquid as well as the activated carbon stage at the end. The Ozone absorbed into the scrubbing liquid will help sterilize it and help oxidize any VOC's that enter it, the remainder of the Ozone should be absorbed by the activated carbon stage.

I purchased several round galvanized gutter downspout pipes from the hardware store and some steel wire. I rigged one of the pipes to run a single steel wire along the center of it and connected it to my high voltage circuit. As the pipe was energized, I shot the fog machine into one end. NO SMOKE CAME OUT THE OTHER END! As I turned the high voltage electricity off, the smoke started to pass through pipe. It was like magic! At last, I had a device that worked for sub micron particles!

Now it was time to cut up the pipe into sections so I can fit it into a housing. I used a general guideline that there needed to be 200-800 ft^2 of collection surface per 1000acfm. I approximated that my vacuum motor is providing roughly 100cfm. If I cut the 2inch diameter 10ft length pipes into five 2ft lengths, I could use five pipes go give me 25 pipes total with one pipe section giving me a little over 1 sq ft each. The total square footage of the collection surface being about 25ft^2 for 25 pipes. Electrostatic precipitators are quite bulky!

Electrified Activated Carbon ESP

As I thought to figure out how to incorporate the activated carbon stage as well as shrink this device, a new design came to me. I could combine the activated carbon stage and the electrostatic precipitator stage into one. Since activated carbon naturally has a large surface area, why not electrify it and use this as the electrostatic precipitator? My idea was to have sectional containers of activated carbon that is charged to a high voltage seperated by a small distance from which in between the carbon sections are ionizing grids charged to an opposite polarity to provide corona and ionization. As particulate laden air passes through the ionizing grids, the particles should adhere to the electrified activated carbon which acts as a collection surface for both particulates and VOC's (including any Ozone produced).

I thought to prototype this new electrified activated carbon design in addition to prototyping the tube electrostatic precipitator as I know at least this idea works reliably. Should one implementation fail, I could rely on the tried and true method.

Discussions

MR JIMOH wrote 03/12/2019 at 15:29 point

this is so awesome!

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