Sunday, May 24, 2009

the mini bomba


At some point Carlos brings in this weird looking rusty thing and tells us that we are going to make a small water pump out of it. He instructs me to take the thing apart, but damn is it rusted shut. I hand it back to him and he works his magic to persuade it apart. On one side there are two threaded openings for pipes and if you peep through the holes you can make out a small turbine which really just looks like a little plastic fan.

The turbine is connected to a mess of copper wires and magnets in the middle of the unit. At first i understood the whole thing to be a device for generating electricity, but further research uncovered that its a cast iron electric water pump (which, like any electrical motor, can be run in reverse to generate electricity, though this is not its primary use). Carlos cleared out all of the extraneous electrical jazz and told me to attach the rubber from a bike tire to the axle and mount the whole thing on an angle iron base.

The bike tire fit perfectly and attaching it was really pretty simple, it just took two pieces of wire twisted around it to hold it on there nice and snug.

After i cut the angle iron to the appropriate length it needed further modification- one side had to have a notch carved out so the screw holes would reach far down enough on the metal. And the pump had to have part of it grinded off so that it would make good contact.

I then drilled some holes and attached the pump to the angle iron.

Carlos decided to canabalize the blender i had made. After the presentation we did in Antigua it decided not to work as a blender. I suppose it was fated. Oh well. Saved us a lot of lead time on the pump, really all i had to do was chop off the table and cut the support beams near the drop outs.

I then welded the base of the pump to the rebar support arms that had orginally held the blender. (Actually, i think i did that first, then cut the rebar so that it wouldn't be all floppy while i was trying to weld)

You can see that the pump sits too high above the wheel, which, like the blender, it needs to make contact with in order to function. So by cutting the arms, i could move the whole unit down to make god contact and then weld it in place.

Ugly but it works.

Once this was all done Carlos took over and attached all of the necessary PVC components.

And then we gave it a go. The thing worked great, 7-10 gallons per minute, from a depth of 15 feet to a height of 36. Anneliese made the excellent point that this would work terrifically for a home greywater/rainwater catchement system.

It was really exciting to ride, and it felt very powerful. I think it was one of the most effective and useful design that i had my hand in the whole time that i was there. I also think that of the designs that i can make it holds the most practical promise for a north american audience (though the blender is definitely a crowd pleaser- i mean, who doesn't like chocolate strawberry banana smoothies?)

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