Sunday, July 15, 2007

Latest Tests, Mixed Results, Mostly Good

Well, the pump described in the last post was hooked up and wrung out a few days ago, with mixed results. I have mosly good news though.

The new plumbing worked just fine, as did the new check valves. I was holding my breath about the new valves. The easy up-and-down mast worked too. The new plywood braces were plenty rigid. That leaves the paraffin valves. Results there were less than stellar. Without going too much into the gory details, the paraffin seals were almost impossible to prime, and once primed, the upper seals, the ones that should provide a seal on the vacuum stroke, were excessivly leaky, and wouldn't hold their prime. After a half hour fighting with the balky seals, I retreated to the older molded seals, primed the pump, and everything else worked.

Except the pulleys. The pulleys that hold the cable that raises the treadles on each vacuum stroke have been something we've sort of neglected till now. We were using a pair of old brass pulleys that I had lying about from an attempt to hang a bird feeder where the squirrels couldn't get at it. That endeavor failed by the way. Anyway, the pulleys were too small for the task we had applied them to, and they didn't survive. All the vigorous jumping up and down I did while trying to use the paraffin based seals didn't help any.

The pulleys have since been replaced with three inch diameter pressed steel pulleys with a ball bearing in the center, intended to help raise a garage door. If you click on the photo, you should be able to see the new pulleys and get a better look at the metal bails that hold the mast.

We still have a working pump. In fact, plans are to take the pump to Jim's house, plumb it to his pond, and try to pump the pond dry. No, really, we're going to take advantage of the water his pond can supply to work the pump for as many hours as he and I can make ourselves pump, so as to identify any part that is prone to premature failure. We're also going to play some games involving feeding the pump sand and mud to see how the seals and check valves handle that. We've got some strainers to test as well. Until now, we've been pumping clear water.

There's been some preliminary talk about shipping this pump to Haiti. Should all this testing we've planned work out with no big setbacks, I hope this can happen. The sooner the better. The sooner we can manage to get a pump on the ground in Haiti, the sooner we'll know what works, what doesn't and what needs to be changed.

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