DC Motor Air Pump

Hello Folks! How are you?

I need a air pump for my aquarium and I have tons of DC motors, I was thinking of buying one, but they are so noisy and its so much cooler to use old parts to build something. I found some projects here for water pumps using DC motors, but what I want is to build a system, using a DC motor that brings air from the outside through a small hose into my recipient, in this case my aquarium.
Have you guys/gals ever heard of something like that? is it possible?

kreoo (author) 3 years ago

That is very nice guys! Thank you for the input.

The main problem is not the noise, I think it would be nice to able to build one rather than buying one.

The step mpilchfamily mentioned seems to make sense, I will see if I can build such a project, but by the looks of it, it is no easy task, hehe.

Thank you! and if any of you have such a project ready or if you can do it, please share with the community Im sure skills such as building a pump with a dc motor can come handy for many people.

In my young years I hat a 800litre tank and was actually breeding some fish in there.
One of the big challenges was to get enough air in it, especially when you have a lot of smoking guests.

At first I got a sealed air pump that allowed for an intake hose to be connected, was very quite too but it failed within a year.

The next step was to use a venturi nossle on my water pump and this solution stayed in place for the lifetime of the tank.

With a proper external filter and pump setup I never had to worry about fresh air again, even added a little valve into the air hose as the venturi system was producing a bit too much.

Won't work as good with little pumps that can't provide proper pressure though.

The solutions for DC motors are IMHO useless as they are either very noisy or only for short time use, long time use requires constant repairs and parts replacements.
If a venturi system is no good to you, maybe a little airbrush compressor with an additional tank (old gas bottle) will do.
Compressor fills the pressure tank and shuts off for until the pressure drops too much.

These airbrush compressors are available in "silent" versions too.

If you think the commercial options are too noisy. A home made version won't even come close to matching the commercial options in silence.

It can be done. The motor will have to rotate a cam which can raise and lower a piston in a chamber. The piston has to have an air tight seal on the chamber and will need a couple of flap valves so on the down stroke the air can be drawn in through one valve while the other stays shut. Then on the up stroke the air is pushed through the other valve and not through the intake. It's fairly simple to make the valves out of some rubber. An old air mattress or rain coat would work. The hard part is the piston and cylinder with a good seal and making sure the motor can drive it. So it will have to be small further complicating things.

All the noise comes from the vibration created from the piston moving up and down in the cylinder. Causing the whole think the vibrate. You can insulate against the noise of the motor itself but the overall vibrations and the sound of the air moving through the valves is a different matter.