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This instructable shows you how to make an air purifier to filter pollutants such as tobacco smoke, solder fumes and many other organic materials out of the air that you breathe.

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Step 1: Needed materials and Basic Idea

Picture of Needed materials and Basic Idea
How it works.JPG
Computer fan
Activated Carbon
Window screen
Modeler's plywood
Basswood or balsa
12 volt AC/DC converter

If you have enough modeler's plywood, then you can make the frame out of that, but to save money, I chose to glue my frame together with some balsa wood I had. I had everything but the activated carbon, which you can purchase at pet stores, already at my house.

The purifier works by drawing air through the carbon and forcing it out through the top. The picture below is a cutaway view. The carbon surrounds the purifier on four walls with the fan on the top. The large surface area allows the air to pass through slowly which cleans the air much better.

Step 2: Make the Frame

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This part is critical since it is what keeps your filter from falling apart, so cut and glue well. For the edges of the walls, I used 1/4x1/4 inch strip of balsa. To support the middle, I used 1/8x1/4 inch strip of balsa. Next, make 4 of both the inside and outside walls. You may need to cut some small squares of paper to stick in the corners for extra support.

After the walls dry, lay the window screen out on wax paper. Apply a thin strip of glue to one side of each wall and place onto the window screen. The wax paper will keep the glue, which will run through the screen, from sticking to your table.

After the glue dries, cut each wall away from the sheet of window screen.

Next, cut a 45 degree angle in two sides of the wall so that the four outside and four inside walls can be joined to each other. Make sure that the window screen is on the outside of the square. In the end, you should have two squares with four walls covered and two left open (for the top and bottom of the filter).
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hazimmzaidi3 months ago

did you make this product as a filter for vehicles?

Great Idea, One idea though:

You can buy these dryer sheets that are designed to give you clothes a nice smell, you should buy a box of them and tape them to the window screen.
Hatty (author)  Michael_Bell4 months ago

Activated carbon physically captures pollutants. Dryer sheets just mask odors.

Hi. Is it possible to use activated carbon as car smoke filters?
Hatty (author)  Angeeeeeeelika4 months ago


undrline1 year ago

I like this. Looks like I could make a less precise version out of anything, even popsicle sticks. I'm curious about the air flow, though. Especially after the carbon has settled, how hard is that fan working? I ask because I'd want to reverse the direction of the flow and make it flatter rather than cubed. Like you said, forced air is more difficult. Also, how often would the carbon need to be refreshed?

Hatty (author)  undrline4 months ago

The fan doesn't work very hard due to the large surface area of carbon. This allows the air to move slowly through the carbon which reduces the load on the fan. Making the filter flat is possible as long as you maximize the surface area of the carbon.

I replace the carbon about once per year.

beatbox.sir10 months ago

this is nice... and i could use it as a base research for my papers... thanks... but could a fan run in a 5 volts ac??

Hatty (author)  beatbox.sir4 months ago

All computer fans use DC and most 12 volts. If you want to use AC power, you need an AC fan.

drmzsz74 months ago
Would this work for scrubbing ammonia gases from pet litter?
Hatty (author)  drmzsz74 months ago

Yes. It will reduce the smell from a litter box.

Activated coconut carbon, Bentre provine, Vietnam

bettablue3 years ago
i have found something better than aquarium carbon.

you can buy surgical masks that have a type of active carbon material layered between two needle punched non-woven fabric they are great.

the needle punched fabric filters out dust
and the active carbon material can filter out bad smells
the surgical mask can also filter out viruses and bacteria so it works like a hepa filter! all you have to do is cut of the ear loops and the sides so the pleats open up then you can use it. it costs like £3.00 for 50 masks so it is so cheap and they last for about 1 month.
csatchell6 years ago
This device is exactly what I am looking for, but one question: How do you attach the 12 volt AC/DC converter to the fan wires?
Hatty (author)  csatchell6 years ago
There is just a positive and negative wire coming out of the fan and I hook that up to the positive and negative output of the power supply. Its as simple at that.
ah yes but be careful when doing so i would recomend getting all of your connections together and semi-permanently fastened BEFORE even plugging it in and i mean i know it is dc but what if the transformer where to break just then? ill tell you what you would have a positivie and a negative end of AC power going from one hand through your chest and heart, to the other
Hatty (author)  killprogram4 years ago
12 volts isn't really enough to break the skin and get into the body, so there really isn't much danger. But anytime you work with electricity you need to take precautions.
Wally_Z Hatty4 years ago
Well, you won't feel 12V. But if the amperage is high enough, it'll kill you if you let it arc across your heart.
12v cant arc across your body. The resistance of skin is too much. In any normal case, when working with 12v and under it is impossible to shock yourself unless you soak yourself in water for a few days.
If you actually READ what I wrote you will realize that I said "If the AMPERAGE is high enough, it'll kill you if you let it arc across your heart". Bad read^. AMPERAGE IS THE KEY WORD HERE. Google it if you don't know what that means.
You need voltage for amperage to kill!!!
I have put my fingers across a 12v 5a source and i didnt feel anything. You need at least 40 volts with moist skin to even feel anything.
Think of electricity like water. If you put your finger at the end of the faucet no water flows. This is like low voltage (pressure of water is low) and no amperage (there is no water coming out.) If you are using a hose, there is some water leakage because the pressure is higher so it means that amps are flowing. Basically you need some voltage to make amperage effective enough to kill.
30mA kills a person at 230v,
Ampere = Volts/Resistance, in this case 12v / 1000r (resistance of the skin)
Therefore Wally_Z's arguments are invalid.
Yeah yuo are rigth! V=R*I (V=Voltage in volts , R=resistance in omhs and I is current in amperes),WELL this is the OHM Law,and on the other side any DIELECTRIC have a constant, a point that change from not conductor to a conductor(For example the dialectric constant of the air is about 3 Kilovots(3000 vols)...so taht explain the spectaculr pictures of tesla or the ligting)..
THANK YOU!!!!!!!!!!!!!!!!!!!!!!!!!!
Some people need to know what they are talking about, SERIOUSLY!!!!
cut the wire open and solder the + to the red and _ to the black. If you cant tell which is + and - guess and if the fan doesnt work, switch the wires.
you might actually try three fans in line. say for argument's sake the first fan gives you one bar of pressure, a second in line would double that to about 2.3 bar of pressure and a third would then daouble that to about 4.6 bar. in theory that is.
gilbert20486 years ago
this could be good for a solder venting system
Hatty (author)  gilbert20486 years ago
It actually does work as a solder venting system. The only problem is that it doesn't suck in air at a high enough velocity to make it effective. Even though it does suck solder fumes in and filter them very well, most of the fumes just go straight to my nose. If I wanted to make one, I would probably only have one side of carbon, use a converging nozzle into the fan, and only use a .25" thick wall of carbon. This would allow for a much greater airflow and, hopefully, pull the fumes away from my face. But, since I don't solder much, I think I can do without it.
Chowmix12 Hatty5 years ago
Instead of 4 inlet vents try limiting it to 1 so that the air pressure is not 'diluted' and you will have greater suction towards four soldering station... And also, the fumes going to your face are harmless, after going through the filter...
increase venting CFMs (cubic feet per minute, flow rate) by making a grid of four fans to draw the air. or whatever amount is necessary. the air velocity through the filter should be 200 feet per minute, and big enough to catch all the fumes. quick calculation
thank you for that, and yes i would use a funnel as well
Hey. . . GREAT IDEA!!! I've been wanting something like that for a long time, I can't believe I didn't think of that!
XOIIO5 years ago
Can you cut charcoal filters, or does all the charcoal stuff come out?
MrHyde6 years ago
chamunks MrHyde5 years ago
I'm curious how you would use this turbine to create pressure or apply the turbine to this.  Maybe I'm just browsing instructables too late at night. 
By manually spinning the shaft of a tesla turbine th opposite effect is acheived and pressure is generated
cant you make carbon??? i saw in a science book you add something to sulfic acid and carbon is made :-\?
I dont think you can make carbon, unless you do some nuclear fission or fusion of lighter or heavier atomic nuclei. Carbon is an element.
oh i remember, if you put sugar into a thing of sulfuric acid, you can make carbon! thats all :-)
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