Plans for simple air pump?

orb · Jul 7, 2004

I'm looking to buy an old windmill to use as a power source aerating a waste lagoon. Anyone have any plans or ideas on making an air pump using the up and down action that a windmill will provide?

Obviously a bellows style pump would be the easiest to construct but I'm worried about premature failure of the flexible air bag material. I think something along the lines of a bicycle pump on steroids might have a better chance of a longer service life.

What do you guys think?

Orb

BobReeves · Jul 7, 2004

Good idea for almost free energy... I would think it would be pretty easy to change the up-down motion to circular (steam engine) but depending on how large your lagoon is you may need allot of air volume. Not sure what you could use for a pump, maybe some sort of turbine with a small pulley. Put a large pulley on the windmill engine and hope it has enough horsepower to drive it.

bobodu · Jul 7, 2004

I remember seeing on the show Junkyard Wars where they used tires for bellows.You would have to use plate on each side of the tire.A couple of large check valves or some home flappers and you are on your way.

Darren · Jul 7, 2004

Using a bicycle pump as an example, it shouldn't be difficult to make a much larger version out of PVC pipe. The sucker rod on a windmill moves up and down so you'll mount the pipe vertically in line with the rod. You'll need to figure out what to use for valves. You'll need one to allow air at the bottom of the cylinder to only move out to the line to the pond and another on the piston to allow air into the cylinder on the upstroke and close on the down stroke.

The seal on the piston could be setup to leak air on the upstroke, filling the cyclinder, and have a tighter fit on the downstroke to capture and compress the air. With 8 or 10" pipe for a cylinder and enough stroke you could compress a lot of air. If the stroke is fairly short, go to a larger diameter pipe.

I wonder if the regular leather seals used for water would work to pump air if they were above ground? I'd find a diagram for the water pumping setup I expect they'd also need at least one valve. If I remember correctly those were cup shaped seals on the piston. They might have to be wet to work well.

You may not even need seals if you have a close fit between the piston and cylinder. It doesn't matter if a little air leaks past.

orb · Jul 7, 2004

Darren,

Your PVC pipe idea is exactly what I had in mind. This is not a high pressure system we are talking about, just something to move a lot of air volume.

I know someone out there has done this before and figured out all the parts, lengths and volumes; I just need to find that guy. I remember a while back someone posted a link to the Canadian version of our AG Extension service. On their web site they had plans for building all sorts of farm implements and buildings. Anyone know of a similar site for wind powered equipment?

TBAR · Jul 9, 2004

Why do you want to pump air? If you are just trying to turn the water over from bottom to top use a standard wind mill well pump and draw from the bottom of the lagoon and discharge at the surface. This would be alot easier than redesigning the wheel to pump air.

TBAR

Windmill Pic 1
Windmill Pic 2

dbelisle · Jul 10, 2004

If you are looking for check valves, look in a plumbing supply store for a sewer ejector check valve.

They will stop they the back flow of air as well as sewer and are under $20.00 for a two inch.

Darren · Jul 10, 2004

The problem might be the solids at the bottom of the lagoon if it's for manure storage.

have_blue · Jul 10, 2004

A 2 or 3 gallon garden hand pump sprayer comes to mind. It wouldn't last very long, but is cheap and would be a quick way to tell if it would work. Just drive a stake, strap the sprayer to it, and extend the hose to the lagoon or to a tub of water and see how it works. Also, study the air pump piston, O ring, cylinder, and the flapper valve inside the pump. They're very simple, and could probably be scaled up with PVC and a little ingenuity.