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A small DIY air purifier

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Re: A small DIY air purifier

#51

Post by insensible »

thehesiod wrote: post #22
kn100 wrote: post #6

This is a really cool project but frankly you can do it a lot cheaper. Find the cheapest box fan you can find, and find the cheapest HEPA filter you can, and strap the HEPA filter to the front. To improve air purification even futher, slap an activated carbon filter on the front too, and your air purifier now filters VoCs! For cheap Activated Carbon Filters, look into the kind used for Aquarium filters. They'll work…

know a way to get them to US reasonably? cost is like 10x when shipping to US :(

In the US, grab a basic 20" box fan and toss on a 20x20x1 furnace filter like this one:

https://www.homedepot.com/p/Honeywell-20-in-x-20-in-x-1-in-A...

For extra flow, set up a triangle with the fan on one side and 2 of these filters on the intake end as the other two sides, and duct tape some cardboard to seal the top and bottom.

Re: A small DIY air purifier

#52

Post by robryk »

adrianN wrote: post #26
ivanhoe wrote: post #18

if you don't mind a noise you could buy a 2nd hand vacuum cleaner with a built-in hepa or water filter (ideally also with adjustable speed to make it less noisy) and just let it run without a hose, sucking the air and pushing it through the filter...

If you don't mind the noise and wasting a kilowatt on something that can be done with two dozen watts.

The vacuum cleaner would have much larger airflow though. Would it still have higher energy usage per unit volume of air pumped?

If not, then cycling the vacuum on and off would actually Dave energy compared to the small fan setup.

Re: A small DIY air purifier

#54

Post by blablaguy »

there is also some other air filtering project on github. maybe a bit more powerful but more expensive and definitely more ugly. https://github.com/KarstenSiemer/Open-Airfilter

I don't really think airfilters in that size so much. They need to push a serious amount of air through the filters to be able to accommodate for natural air circulation. Some pc fans don't do the trick I'd suspect

Re: A small DIY air purifier

#55

Post by pritovido »

littlejohnny wrote: post #45

How about a 'filter' that can 'wash' the air with clean water. To me it appears to me the best possible solution to clean air in a confined space. To put it simply, air can be bubbled through the clean water, to scrub it of both particulate and chemical contaminants. No doubt the apparatus will lend itself to several technical challenges like noise and the need for periodic changes of the water. I believe such air pu…

They do exist.

The main problem of air washers is that it is not enough to change the water.

Fungus and spiders love the wet environment. Algae start growing if there is sunlight using just the dust particles on air as food. Also very bad bacteria like salmonella and others could grow if the water gets warm.

Re: A small DIY air purifier

#56

Post by ivanhoe »

adrianN wrote: post #26
ivanhoe wrote: post #18

if you don't mind a noise you could buy a 2nd hand vacuum cleaner with a built-in hepa or water filter (ideally also with adjustable speed to make it less noisy) and just let it run without a hose, sucking the air and pushing it through the filter...

If you don't mind the noise and wasting a kilowatt on something that can be done with two dozen watts.

That kW will move you more air in 30 minutes than PC ventilator can in a whole day, especially if you're trying to push it through hepa filter which is fairly thick and adds quite a resistance.

Re: A small DIY air purifier

#59

Post by Spooks »

marcinzm wrote: post #50
kn100 wrote: post #6

This is a really cool project but frankly you can do it a lot cheaper. Find the cheapest box fan you can find, and find the cheapest HEPA filter you can, and strap the HEPA filter to the front. To improve air purification even futher, slap an activated carbon filter on the front too, and your air purifier now filters VoCs! For cheap Activated Carbon Filters, look into the kind used for Aquarium filters. They'll work…

This may or may not work, cheap box fans aren't designed to push/pull air through obstructions (ie: low static pressure) and HEPA filters are giant obstructions. So instead of the air going through the filter it'll go through gaps, around the edges of the blades, etc. I used a cheap box fan for some DIY ventilation and the loss in airflow is massive after filter and ducting.

couldn't you easily test this by sticking your hand (wet it first) in the middle section of the filter and see if you feel any air coming through
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