Freeplay invented a wind up torch & radio a couple of years ago and I think the mechanical power could be converted to create a thin film evaporation process in a freshwater maker. Small device as a required emergency unit in boats. No need for electricity. Can simply be wound up.-- leggless, Jan 18 2008 Trevor http://www.ogormans.co.uk/Bayliss.htm [po, Jan 18 2008] Lifestraw http://www.gizmag.com/go/4418/A half-baked device if ever I saw one, but it works. [DrCurry, Jan 18 2008] Look ma, no handle. http://www.greenhom...ter_filters/106608/ [2 fries shy of a happy meal, Jan 19 2008] Do you mean generating electricity for a sort of mini-still? I'm not sure, but I'd think there are better ways to do this. For one, you'd get much more power from a very small and cheap wind generator, or even a smallish solar panel (I would imagine).
Also, I wonder if heat-based evaporation is the most efficient? How about a system that compresses a volume of air (which will be moist if you're at sea) to drive condensation?-- MaxwellBuchanan, Jan 18 2008 You don't need electricity at all to purify water, whether from power lines, batteries or wind up devices.
The most elegant solution I've seen so far is an oversized drinking straw with a filter in it. For generating larger quantities, though, sunlight is the way to go. If you are looking at a place without sunlight, then I think you'd want a device you could hook up to a bicycle - pedalling a bicycle is much easier than cranking a crank.-- DrCurry, Jan 18 2008 You could use mechanical power from a Freeplay powerplant to pump water through a reverse osmosis membrane - that would work.-- 8th of 7, Jan 18 2008 Or you could cut out the middle man, technologically speaking, and pump the water through the membrane by hand (and that has been done).
(Still reading this as "Wind up Watermelon")-- DrCurry, Jan 18 2008 A filter won't help if the water is brackish or salt. Solar devices are the way to go, there. And they don't need constant cranking to keep working, either.-- elhigh, Jan 18 2008 //A filter won't help if the water is brackish or salt// No, but a reverse- osmosis membrane will. It is effectively a molecular filter.-- MaxwellBuchanan, Jan 18 2008 Yes, and water could be pumped through it. That could be made, and may already be.
The posted idea, on the other hand, is really a wish. Freeplay makes electricity, but the post mentions mechanical power, which isn't Freeplay at all. What is a "thin film evaporation process", anyhow? <Googles> <goggles> That's a high-tech process using heat or a vacuum. I don't see it working for a hand-held unit.-- baconbrain, Jan 18 2008 I've seen hand-pumped reverse osmosis purifiers on TV (so it must be real). I think the idea is meant to use a Freeplay-style generator to power an electric purifier (the penultimate sentence means, I presume, no need to provide power from an external electrical source). It's probably doable, just not very efficient.-- MaxwellBuchanan, Jan 18 2008 Actually, you could run the purifier from a wind generator, and it would still be a wind up watermaker.-- MaxwellBuchanan, Jan 18 2008 // or a vacuum //
You could use mechanical power from the freeplay unit to improve the efficency of a solar still using vacuum .....-- 8th of 7, Jan 18 2008 //a couple of years ago // 1991. Is that "a couple" after inflation?-- AbsintheWithoutLeave, Jan 19 2008 Seasonally adjusted ?-- 8th of 7, Jan 19 2008 random, halfbakery