To: Homestead mailing list digest <homestead AT lists.ibiblio.org>
Subject: [Homestead] Well Pump Breakthrough
Date: Mon, 16 Oct 2006 01:30:29 -0700
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:
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
[Homestead] Well Pump Breakthrough,
Bill Jones, 10/16/2006