Homestead mailing list

[Bill Jones <billj AT harborside.com>]

Here's a picture of a Stauffer pump.  It costs $500 if you buy one of 
their windmills, $800 otherwise.  About 10 years ago I conceived of a 
way to lift water just by injecting pressurized air into a water-filled 
chamber, to drive it upward through a one-way check valve.  I knew what 
it had to do, but I didn't know how to make or acquire the necessary 
valves.  Later when I first went online, I learned that someone already 
made one:

http://www.airliftech.com/Windmill%20water%20pump.jpg

As of about 3 years ago, I found an easy to make the tube seal and 
refill with water, using a floating ball that presses against a hole in 
the top of the chamber when the chamber is filled with water, and stays 
there during pressurization.  Upon releasing the air pressure, the ball 
falls to the bottom and the chamber refills with water.  But I still 
couldn't figure out how to sense when the chamber is ready to refill 
again.  It's easy to make it cycle at a constant rate, but the rate 
needs to increase when the wind blows harder, producing more air from 
the compressor.

So yesterday I had an idea to put a second identical floating ball in 
the tube, with both balls large enough that they can't slide past each 
other.  Now as the water is forced out of the bottom of the chamber, the 
lower ball will ride downward along with the meniscus of the water, and 
when the chamber empties it will be forced against the bottom hole.  
This will cause the pressure in the air supply tube to increase, since 
the trapped air has nowhere to go, which can easily be sensed with a 
pressure switch!

The only remaining (easy) task is to come up with a circuit that will 
turn on a 3-way solenoid valve (or off, depending on which type of valve 
it is), to turn off the air pressure when the pressure switch cuts out, 
and then delay for a fixed length of time before resetting, to allow the 
top ball to fall and the chamber to refill.

The whole thing is less than $100 and you can make a compressor to run 
it from an old engine.  Our wind nearly always blows from the north in 
summer, clockwise around that offshore high pressure cell I talked 
about, so even a simple windmill that always points north would work 
fine, and it can have a simple belt drive connection.

Bill
S. Oregon coast