Vacuum cleaner with pc fan possible?

[daredriven]

Hi! I would like to ask for some help regarding a project I am thinking of making. Well, the thing is, I would like to make a vacuum cleaner with just a couple of tupperware "boxes" 8sorry, I don't know how you english people refer them to...:P), some tape to prevent air leak and a 63 CFM pc fan. Is it possible? I have tried to do one but did not follow the physics principle and ended up with a vacuum cleaner that had a hard time sucking anything... Now, I have found an image from the inside of a vacuum cleaner and I am interested in knowing if it is feasible and if it will be powerfull enough to move water across some tubes (the water will never come into contact with the fan, as I have a separate compartment for it).
I really wanted to do this thing, as I really need a vacuum pump for school and buying a 75dB vacuum cleaner is not really the best course of action (having that thing making noise while explaining something to students is not really the best way). Thank you for your time and I hope you don't think I am crazy lol - I am a little, by the way.

 

[russ_watters]

Welcome to PF...

What you need to look into is the static pressure your fan can generate. That's where the suction comes from. Often times the static pressure is measured in inches of water column, meaning 1" of static pressure is enough to raise a column of water 1".

Looking at the spec sheets of a few fans, you'll find that an axial fan (one with blades that spin perpendicular to the direction of motion) doesn't produce much static pressure. A centrifugal blower is what you would need. But you'll also find that the size of fan you get to run on 12V is perhaps 1/1000th the power of a standard vacuum cleaner blower.

 

[yougene]

Could setting up multiple pc fans in-line double the static pressure?

I'm not an engineer( CS major ), I don't know much about dynamics but I'd like to know more about static pressure.

 

[russ_watters]

Yes, static pressure is additive for fans in series.

 

[rcgldr]

If it's ok to have the water in contact with the fan, then aquarium power head pumps are quiet and powerful. The big ones are virtual garden hoses. A link to some submergable pumps:

aquaclear.htm

I'm guessing that the venturi port on one of these would provide quite a good vacuum at moderate volume if you really need to draw air. You plug in a small plastic hose into the venturi port and it will draw air. The pump remains submerged, but the hose can lead to an air chamber.