Does anybody know how to make an air pump for a aquarium out of stuff laying around your house?
YES USE THE CONCEPT OF A WINDMILL POWERING A PUMP! power of windmill=driveshaft to pump air/water
Er, it depends on what sort of stuff you have lying around.
A version that springs to mind requires a relatively-slow rpm motor (or geared motor), stiff wire (such as coathanger wire), a dead ball-point and a length of rubber tubing.
either that or a very small high cfm fan running in to the tubing, it would be quite hard to get just right though, you'd need a specific 'funnel' from fan to tubing and it would do a very limited depth...
That would be very hard to do in a way that would stop water flowing back in the even of a power cut.I was thinking about something like those peristaltic pumps that they use on kidney dialysis machines.
. Not hard at all. Anti-siphoning valves (check valves) are available at most aquarium supply stores. Or just mount the pump above the water level.
. I would not recommend a peristaltic pump for aquarium air. They can put up quite a bit of pressure (basically a positive-displacement pump), which can cause the air tubing to rupture or blow off of fittings, which in turn can lead to siphoning if the break is on the wrong side of the check valve.
Ah, but the question was about stuff lying about the house. Personally, I don't have a check-valve lying about the house.Hmm, I just had a look inside the air-pump for my old Biorb aquarium - it's a pair of non-return valves with a small chamber between. One side of the chamber is a flexible diaphragm pushed in and out by a vibrating solenoid. It could be fairly reproducible with a bit of work (although, I suspect, and version I make would be larger). It's probably easier / cheaper to buy an actual pump.
. OK. But they can be had for less than 2 USD. A lot cheaper than most fish and certainly cheaper than replacing flooring.
. That's how most of the pumps for home use are constructed. The generic name for the valves is "reed valve." Does the solenoid direct-drive the diaphragm on your pump? Most of the ones I've seen use a lever to drive the diaphragm, with a coil & permanent magnet driving the lever.
It's direct, and quite rapid - if I'd seen it running apart, before I saw it pumping, I would have said that it was running too quickly to pump efficiently.
> quite rapid
. Probably 50Hz (mains frequency, so 60Hz on the left side of the pond).
. Sounds like that arrangement would be more reliable (fewer moving parts) than the lever style I'm used to.
Since it is supposed to run, effectively, for years without stopping, that's probably why.
That could work, it seems like a safe bet aswell, either that or some form of archimedes screw pump could be formed from household materials.
Archimedes screws pump fluids (or granular solids) uphill - I can't see any way they could be used to pump air downhill...
I was thinking aerate the water and put it back in, taking water out and dropping it back in even dissolves a quantity of air in it, dropping it through a series of steps before the water would probably get a decent amount of air in.
I know it's kinda backwards thinking but it just seemed a nice simple option...
Maybe a super simple bellows pump, a platic bottle with some form of valve on one end and a motor driving an eccentric cam to push the bottle in and out.
No, it's simple - Wrap a tube around a central shaft (driven however you like) to make a helix, and arrange it at a fairly shallow angle (say, 30o above horizontal), rotating so that the open end of the tube dips down "face first" into the water. Every time the face dips in the water, it traps a bubble of air, which is pushed along the tube as the helix rotates.Every turn of the shaft would give a blup of air at the bottom of the helix.
You know I believe we've over thought this a little...
Oh! Yes, I can!Turns picture round in head... gosh - what an odd thing to do.
. I doubt if you can DIY an air pump that will be as small, efficient, quiet, and (most importantly) reliable as a store-bought one. They are very easy to rebuild, so make sure you get one that has spare parts (mainly the valves and diaphragm) available and your long-term costs will be lower.