DIY air purifier inspired from cyclone technology built from simple starting material

This is a trial!


This is homemade and this is not made with any warranty of any kind in particular it is not sure that this device will work or that this device will not cause any damage.


I do not give any warranty about this device will work for you. Mine is only half working and therfore I expect your help to improve the design :)

The design of the wings of the computer fan is not appropriate apparently.

I tried to hack the computer fan by adding some extra without any significant improvement.

How to turn a computer fan into an impeller or turbine in an easy/simple way (in order to pushing the air into one direction only).

If anybody has a suggestion for such an improvement I would be very thankful.

Just a mention on the contents of this instructable-->attribution non commercial sharealike. You can re-use my texts and my pictures, modify or whatever, if you do so please cite the author, my work or even better put a link to this instructable.

I would appreciate your cooperation :) In addition if you have any comment or improvement that you would like to share with me please do it.

as usual:


plain text

safety issue or important notice


Step 1: Storyline

I was working on such an idea since I was living in a very dusty place where electric storage heaters were used.

I bought first an air purifier that was ionising the air, I felt a clear improvement but ionising sounds to me unhealthy on the long term.

However, I though that other ways can be investigated.

Basically you need in any case a fan that will allow you to catch the dust from air. The air free of dust is then released into the room.

I saw other purifiers methods with a filter (even a furniture in kit company from Sweden is proposing such a system).

I wanted a filter free method. I come to the cyclone technology which is known since a long time (and no.... a famous british company that is making vacuum cleaner without a bag did not invent it, they applied it to a novel range of activity, with my deep respect Sir! This was very clever!)

Different designs are known but mainly they always copy or adapt the same procedure. That you put one single cyclonic room or many smaller cyclonic rooms, you always try to achieve the same.

The following paragraph may not be right from the scientific point of view but this is my understanding.

Description of the cyclonic device (see the picture):

The air is propulsed into the funnel from the upper side loaded with dust particles, the air moves down by drawing a vortex around the central tube in the funnel like part. The volume on the upper part is bigger than on the lower part. As a consequence, the particles are accelerated. Locally the carrying air flow has increased gradually by travelling down in the funnel.

I depicted this to myself like when you played with a garden plastic hose, squeezing it more and more to see how the water flow becomes smaller and smaler, and more and more powerful.

At the bottom you find a bottleneck open onto a bigger room causing a sudden local decrease of air flow, where the dust is collected.

The dust particles carried out by the air flow kept moving down due to their inertia when suddently the air flow decreased.

The air moves further through the central tube -the chimney- before being released into the room free of dust.

Step 2: Conceptualisation

The idea

So from that point I thought how can I achieve something similar without the vortex around the chimney implied by the cyclone technology.

I wanted a straight design.

So what is needed:

-an air input

-a funnel where particles are accelerated

-a collecting chamber where the dust particles go down in a free fall manner

-an air output

From this idea, I draw two vertical side funnels where the air flow is blown through a bottle neck. At the entrance of the collecting chamber, the air flow dimish suddently and the dust particles by a free fall and because of the kinetic energy accumulated, those may be trapped.

At the bottle neck is found also the air ouput „chimney“. The air follows a vertical and then horizontal path as shown on the picture.

Step 3: ​ the Inventory: Everything You Need

-a PET bottle squarre

-a computer fan (DC current)

-a mobile telephone charger (DC current, check that the voltage and the intensity does not overcome the computer fan parameters)

-an electrician tape to protect wires

-condensed styropore foam

-a knife for meat (with large teeth) or better a styrofoam cutter (This is a heating filament I think)

(you can replace that by Polyurethane foam in spray, I do not describe this one)

-a scissor

-a claw to bare the wires of the old tel charger

-a clean place

-if you do not know electric work please let people with knowledge help you.

-if you are not 18 or more please do it under the supervision of an adult

Step 4: Mounting Instructions

Mounting instruction- the fan:

Danger: electric Hazard! Work safe!

A) take the charger and cut the cable close to the end, extract the copper wires with the special claw. You must have a red and a black hose for the two wires, if not you will need to test that.

B) plug the copper wire into the fan socket (the white box where the three wires are connected) the red wire against the red wire of the socket and the black against the black.

Try by plugging the charger, the fan must run.

If the wires are not coloured and the fan is not running you need to invert both wires you plug into the socket because only one current direction is here working (as it is DC current)

C)if the fan is blowing air then this part is ready. Protect the construction using the electrician tape

Mounting instruction- the funnel and the collecting chamber:

A) cut the PET bottle at 1/3 or ¼ from the neck with a scissor like one of the previous pictures

Danger you can cut yourselves

B) cut the styrofoam with the help of the knife so that you obtain two sides funnels formed by the styrofoam and the wall of the PET bottle.

This takes time to make it air tight on the sides and open where the funnels are (to allow the air flow going only along the funnels)

C) Hollow out the foam from below through the bottle neck. And then hollow out from the side (at 90° of the funnels. A diameter close to the bottle neck one is wished.

You just realised the air output chinmey. No air leakage is allowed here. So if you dig too much please glue it to make it tight with the appropriate glue (most glues are not appropriate and you will have a very bad surprise, better trying first on a trashed styrofoam part).

D) place the bottle neck on the other part of the PET bottle like on the picture.

E) make it air tight (with tape)

F) Shape a junction between the fan and the bottle neck out of styrofoam. It must be air tight

Step 5: Final Stage, Is It Running?

Do Not let it run when you are not in the room!

Final stage and improvements issues
mount the styrofoam junction onto the bottle neck. Mount the fan on the junction, being sure that the air is blown downwards.

You must obtain something like on the picture


I feel air is blown through the air output yipeeeeeeee! But, and yes but, the fan is blowing air also backwards. This is because the fan is not strong enough I suppose and my output chinmey is too narrow (I emphasize to make it big enough for that reason).

And this is a problem because then dust will not enter the system, it will be pushed away by the air bed resulting by this backdraft.

I put styrofoam small parts below the fan, inside the system to see if the dust may be collected. The point is yes it does!

-Maybe the computer fan design is not appropriate and must be modified. Indeed, I can imagine that dust is a problem for computer components, and it will be a big plus having a fan which blow air to cool down your computer and at the same time create a air wall at the entrance of the air as an hinderance to dust contamination.

Please feel free to share ideas and improvements, I am looking for that!

<p>Does it actually collect dust? Since the pm2.5 dust is really small, I believe you still need HEPA filter</p>
<p>hey can this be operated by battery</p>
<p>Very cool!</p>

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