>Desalinator is a must for such journeys How do reverse osmosis pumps work? And what do they cost? I live in South Africa where anything like this has to be imported and costs a bomb. Cheers Paul -------------------------------------------------------- Confidentiality notice: This e-mail and any files transmitted with it are solely intended for the use of the addressee(s) and may contain information that is confidential and privileged. If you receive this e-mail in error, please advise me by return e-mail immediately. Please also disregard the contents of the e-mail, delete it and destroy any copies immediately. *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
RO desalinators force salty water against a semipermeable membrane which has pores so small they prevent the passage of relatively large materials such as sodium ions, potassium ions, and chloride ions, while allowing the passage of smaller water molecules. The pressures required are quite high, so that either a high pressure powered pump is needed (e.g., units usable aboard ships) or a strong arm on a long lever (e.g., the hand-operated ones). About a liter an hour for the hand-operated ones. At home, you'd pay money for a four-hour workout ... Silt clogs them, so a pre-filter is a must They grow algae, which clogs them. They leak. But, nothing else will do the job. A pdf source ... more than you want to know ... : http://www.practical-sailor.com/newspics/charts/881water.pdf The Pur Survivor-06: http://www.safetycentral.com/survivor06.html (about $US 600) And, the Katadyn 35: http://www.katadyn.ch/site/sg/home/marine/ou_products/survivor__35/ Google can make you knowledgeable ... -- Dave Kruger Astoria, OR -- ----- Original Message ----- From: "Paul Ash" <AshP_at_sundaytimes.co.za> > How do reverse osmosis pumps work? And what do they cost? I live in South > Africa where anything like this has to be imported and costs a bomb. *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
> How do reverse osmosis pumps work? And what do they cost? I live in South > Africa where anything like this has to be imported and costs a bomb. Since Dave has already explained how do they work, I could tell "how do you work them" :-)... You pump, and pump, and pump. 1 liter per hour for PUR-06 (didn't see them cheaper than $500 new, but got mine for $150 - army write-offs, 6 yrs old). They exist in "military" modification, i.e. with extended levers, and used units are often sold with such levers. Pretty small, I keep it in a bag 6"*10". Pumping is easy, prescribed frequency 1 stroke per second can be maintained by alternating hands. But is is so boring... Doing this every day for 4 hours will drive your crazy - and it takes energy too. Incredible Timo Noko :-) has designed wind-operated PUR-06, photo can be found on his website. After you use it in real-life conditions, and then leave it for more than a few weeks, you have to either pump clean chlorinated fresh water through it (preferably, once a month), or fill it with "biocide" solution to prevent micro-organisms growth on the membrane. PUR-35 costs 3 or 4 times more, and is 2 or 3 times larger (but again, see T. Noko's modification with removable fiberglass lever), and can provide 3.5 or 4 liters an hour. It is said to be more difficult to pump, but it has longer lever, - so I don't know. I never tried it. It can be used with 12V motor, but is sold without a motor as well, with a handle for manual pumping. There is also PUR-40, which is said to be more sturdy than PUR-35 (and probably provides 4 liters an hour). With a motor the efficiency will be much higher - I don't remember the specs. They are made by "Recovery Engineering". *************************************************************************** PaddleWise Paddling Mailing List - Any opinions or suggestions expressed here are solely those of the writer(s). You must assume the entire responsibility for reliance upon them. All postings copyright the author. Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
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