Making Cheap Electrostatic Air Cleaners

I had similar problem when the step daughter developed what the Dr. explained as a dust allergy. I asked him to write a prescription for an air cleaning device; generic. Then with the prescription (tax deduction) I bought a Princess Vacuum cleaner. These have a three stage filtering system, as vacuuming is occurring no dust will be allowed to escape the machine and you can leave it run for couple hours to filter the air of a space too. I've had it twenty years and it's lifetime warranty is effective but haven't needed yet.

Get a HEPA air filter unit. They do better than electrostatic air cleaners (I've had both). You can get small ones for a bit over $100 that are good for a single room or bigger units that will cover an entire house that has good air circulation.

Since you don't apparently run the forced air unit, a whole house system would be a waste.

HEPA filter replacement can cost $100 or more but they only need replacing every few years. Prefilters, cheaper, have to be replaced and or cleaned more frequently.

The HEPA filtered vacuum cleaner will not blow dust back into the air in any significant volume. You might find an adequate substitute to be a waxy cloth or a microfiber cloth with a sprayed on dusting wax (or whatever is in the dusting sprays you place on the cloth, not the furniture. You can get this stuff for dust mops you use on the floor too. Holds the dust until you was the mop head.

GA, guest. My experience parallels yours. We tried a large Honeywell electrostatic air filter in our central air conditioning just upstream from the air handler in the attic. Cross-sectional area is about 4 square feet. After a year or two of operation with recommended cleaning intervals it started spitting ozone. As time went by it got worse to the point where it was doing real harm to my wife's allergies and asthma. We replaced it with a brand new unit and the same cycle repeated only in a shorter time.

Then we found HEPA filters on the internet that were a direct drop in replacement for the removable metal filter cells in the Honeywell unit. Air quality is much better and my wife reports a significant improvement in her breathing. We actually run the fan part of the central system continuously about half the time usually at night. Also on the system air inlet we have always used the usual furnace filters except of a fairly high grade to rough filter the big stuff out of the air before it gets to the HEPA filters. This inlet area totals about 5.5 square feet between two grates. I usually vacuum out the front of these filters every couple of months and replace them twice a year.

Our house is in a particularly dusty mountain area in the Californai Coast range. The size is 1400 square feet and as California houses go I'd say it's about average in its ability to leak air from the outdoors. The air handler circulating fan Has a 1/3 HP motor running a squirrel cage blower. Use of it has a significant effect on our electric bill. And we still have to dust the furniture and venetian blinds pretty often. Our pellet stove for winter heating doesn't help this any.

One other comment about DIY approaches. The Honeywell filter power supplies run at about 8000 volts. You'd best know what you are doing. Don't try checking them with a good DVM.

Ed Weldon

Rhabe -- It's a good answer; but not because I think the OP should be taking the DIY approach. I just don't know enough to say that.

But you have given a lot of information on the subject that is interesting and informative to me and I suspect others of us.

I do think it's worthy of note that Honeywell developed those electrostatic air filters some 40 years ago when the health problems associated with ozone were not widely understood. I think they kept that product on the market for longer than they should have. I'm not sure; but I think they no longer sell those things into the residential market.

Ed Weldon

Hi,

I have an old one from Honeywell, (bought back in 1981) that we used to filter the air that entered a plastic tent. That was attached to and used to shield a lapping machine from outside dust that resulted in scratches.

I will have a look if there is an ozone removal filter built in.

Early laser printers had that filter. I did never take apart a new one younger than built 2000 or later).

RHABE

Honeywell still sells Electronic air Cleaners. They are approved by the American Lung Association. They are the only ones that I use. I have one in my own house.

The biggest problem with air cleaners is not the unit directly. Poor installation practices will cause poor performance as well as ozone problems. The other issue is maintenance. Proper cleaning at regular intervals is also required. I have seen air cleaners where the pre filter screens are missing and the main cells are so packed with dirt that you can not see through them.

Icarus - Thanks for you comments. They are interesting and instructive.

And they lead me to suspect that the issues I had were maintenance related. I paid a good bit of attention to this and followed the manufacturer's instructions relative to frequency of cleaning in the dishwasher. My suspicion is that something in the dishwashing process, either the detergent, the water or a combination of the two might have created a surface transfomation in the filter materials leading to increased conductivity and possible greater sensitivity to humidity changes.

We soften our well water, since it is fairly "hard". But softening doesn't remove the minerals. It just exchanges them for minerals that are more soluble in the water. There are times when the softening does not work as well as it could and under such conditions mineral deposition in the drying cycle of the dishwasher could have been a culprit. I have observed that over periods of years the everyday kitchen glassware develop what looks like an etching of the surface due to our particular dishwasher chemistry.

My question to you has to do with your water quality and the method you use to clean your main filter units, the ones with the high voltage wires. Would you take a few minutes to share your experience with such maintenance work?

Ed Weldon

looks like an etching of the surface due to our particular dishwasher chemistry.

Hi Ed Weldon,

I experienced the same but with very pure water (no hard water here locally but some dolomite (Ca-Mg(CO3)2) added by the supplier to bring down corrosive action on metals).

Our glasses developed a faint blue tint that was corrosion by a too strong dishwasher agent containing chloride.

The blue tint originates from interferometric principle of the etched surface - like anti-reflection coating on optics. The etched parts leave a glass with a leached surface, if blue then only with an optical thickness of a quarter wavelength or 0.1µm that is near a mechanical thickness of 70 nanometer!

If you want to remove the problems with your water then another type of water softening would be recommendable: complete ion exchange with two exchanger columns, one to be regenerated with muriatic acid the other one with caustic soda.

This will generated DI- water, not allowed to drink as very low in dissolved minerals!

So add what you think is essential for your health. Or mix with too hard water to get good drinkable water. Or mix with a small amount of ocean water to have the may be best mix of minerals suitable for our health.

A very happy New Year to you

RHABE

At first I would soak the elements and filters in a laundry tub filled with hot water and laundry detergent. This was back in the day when a lot of people smoked. I had to were gloves as the nicotine would float to the surface and any contact with skin would give you quite the buzz. Than hose them off.

Today I place my cells and filters in the dishwasher with regular dishwasher detergent and run a long power scrub cycle.

As for a water softener, I can not really propose any ideas; as where I live, the only people that have them are the ones gullible enough to buy one. Our potable water is not hard.

The ides that I do have are the following:

-what is your hot water temperature? Very hot water combined with an aggressive detergent will cause a film to form on your glass ware.

-what is the age and condition of your hot water tank? Is it full of mineral deposits? Is the sacrificial anode still there?

-are there any missing wires (ionising wires) on your cells

-are there any bent or deformed collector plates? Any change in the distance between these plates will cause problems or failure.

-when the cells and filters go back in they must be absolutely dry.

-here is the dumb question. Most air cleaners have two pre filters and two cell assembly's. I have come across instances where a person would pull the first filter and cell and not realize that there are more in the frame. Thus only one half of the unit is being cleaned.

-If your unit has a test button, after reassembly try it. If there is a sparking noise and the indicator light dimes or goes out good. No noise and there is a problem.

to make that electrostatic cleaner you need a cheap dc power supply 100vdc out add voltage doubler circuit 20 capacitors and 20 diodes to cascading it to a few thousand volts also tie negative to to neutral AC in or it will not work add a small tip antenna to the last stage of the doubler cascade careful the tip is hi-voltage you will notice dust collecting at any grounded wall outlet like inside the old TV's

have fun watch out for a shocking experience

I have a woodstove and a Honeywell electrostatic air filter and LOTS of dust in the house. I am thinking of converting to hepa filters. Easily obtainable and no ozone or power consumption.

Sounds like my cheapest, safest and most utility bill friendly option may well be to place 2 television sets a few inches apart, along with running a small hepa filter unit. I have all of these laying around here somewhere. If the hepa needs a new filter, i may just go to a box fan or 2 covered with paper towels, sprayed with enddust or something. How about some type of water filter setup, any ideas on that? maybe pull air through a tank of water, like a supersized fish bubbler? Remember, the goal here is CHEAP and effective. I have a small business, and it is the off season, unless there is another ice storm. $100 for a room sized unit wont cut it. Let alone replacement filters.

How about some type of water filter setup, any ideas on that?

Sure...

How about use a leaf blower or shop vac + tub of water

Scrubbers are very high energy for their job and the particle size it can remove is a function of the energy input - the higher the energy, the smaller the particle size removed.

Basically, it needs to form water drops about the size of the particles to be removed, hence the need for high pressure drop to form these droplets where water is in contact with the air/dust.

There was a design of venturi scrubber which had a flooded venturi throat through which the air was drawn ( as per conventional scrubber) and the drops were then electrostatically charged, getting the best of both types.

Apparently this type could collect well down into the sub micron range without incurring too great a pressure drop, by allowing larger drops to attract much smaller particles.

The Honeywell unit achieves 95% or so efficiency down to sub-micron and has very low pressure drop and power consumption - generally lower than a HEPA filter for the same flow rate. Of course the flow rates an es filter will handle are quite large and a suitable HEPA filter for this flow is big and expensive.

For most es domestic/commercial use, the flow rate through the filter is well below it's capacity.

Making one shouldn't be too hard. You need an array of charger wires run at high dc voltage (generally 2000 or so) then a grid of earthed plates to attract and collect the dust.

The collector plates need brushing or washing every so often to remove accumulated dust. The charger wires don't collect much but need an occasional clean. Otherwise, there is little maintenance required, and they should last a long time without trouble.