Sunday, June 24, 2007

Treadle Pump as of June 23


Today we tested what I'm going to call our first prototype pump, with the new molded leather seals I described earlier. If you've been watching, the first thing you notice is that the pump has grown quite a bit shorter. That's a good thing. The operator can now climb up on the pump without getting altitude sickness. The vertical supports for the treadle and the mast are now trimmed down to seventeen inches high. The pistons are shorter as well. The mast now has one crosspiece instead of two, and the nylon rope we used earlier has been replaced with steel cable. We decided we were wasting a lot of energy stretching the rope. There's little stretch now with the cable, and better performance as you might imagine. The new molded leather seals worked just great. They provided a superior seal compared to earlier seals, and did not lose their shape as I had feared when they got wet again. The pump is quite a bit lighter too with much of the unnecessary wood trimmed away. The reason you still see a lot of holes that don't need to be there is that we're reusing the wood from the earlier test frame. So, today was another good day. We still have a lot to do before the pump is ready to ship. We have to make it lighter, and easier to build, with fewer materials. We have to decide what to do about the check valves, which are the most expensive parts of the pump. At this point, the giant green loopy plumbing you see can also be reduced in size as well.

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