Desalinators

Discussion in 'Gear Talk' started by ken_vandeburgt, Nov 3, 2011.

  1. ken_vandeburgt

    ken_vandeburgt Paddler

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  2. dr_penner

    dr_penner Paddler

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  3. ken_vandeburgt

    ken_vandeburgt Paddler

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    I was wondering about distillation solutions. Dave Winkworth's article is a good read but suggests there is not one available on the markets ...

    I wonder if it would be practical to build a solar still.
     
  4. MartinZ

    MartinZ Paddler

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    Hi Ken,

    I used a desalinator briefly a few years ago (this model). Very impressive but many non-field serviceable parts. For paddling in places where there's little water available I'd love to have one.

    I've played with solar stills and they seem to take all day sitting undistributed to make a quart of water.
     
  5. MartinZ

    MartinZ Paddler

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    I'm again thinking about purchasing a desalinator. I've heard that they can be purchased on EBay way below retail price but will need attention. Has anyone here purchased one this way? How hard was it to bring up to speed?

    Martin
     
  6. camshaft

    camshaft Paddler

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    I just wanted to comment that katadyn customer service is well below par. And personally myself will never be purchasing anything made by them. So just the idea of spending 600-800 dollars on a katadyn product makes me ill


    http://www.sciencebuddies.org/science-f ... p022.shtml


     
  7. Roy222

    Roy222 Paddler

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    A Desalinator can be a simple still.
    Ideally, a still could be put together from your cook wear and a few extra parts. A long condensation tube could be stowed in a kayak. The longer the condensation tube the more water can be condensed. If your not going to make Moonshine a bump box will not be needed. Be careful, steam can burn.

    Roy
     
  8. KayDubbya

    KayDubbya Paddler

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    Getting the salt out of sea water takes copious amounts of energy. There's no getting around it. Passive stills that use sunlight to condense water on a clear plastic film and drip back into a bucket can work but it's not practical for anything other than a true life or death survival situation. If you're planning on relying on seawater for an expedition, you'll probably want to set up several of them to collect any useful amount of water. Then pray that it's hot and sunny all day.

    Katadyn's portable solution is one of the few that can be stowed in a kayaker's gear but I have no personal experience with their systems. I have spoken to a couple of retailers who sell them and they basically advised that they are an unnecessary luxury item for 99% of paddlers. If you're planning a trans-Atlantic crossing they may be a useful item to have, but you're going to need a second person just to pump the handle on the unit while you paddle.

    For the price of 1 manual desalinator you could probably buy an EPIRB, several back-up batteries and lease a satellite phone. That would get you rescued faster than purifying a gallon of water through a manual desalinator.
     
  9. MartinZ

    MartinZ Paddler

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    I paddle mostly in the Sea of Cortez and have to carry all my water. On a 10 day trip, at 4 liters per day, that's 40 liters or four full droms. Along with 10 days worth of food, it can make for a fairly overloaded boat. The pumps I've tried didn't seem to require very much effort - the piston that builds up the necessary pressure is tiny. It seems like it could be done while sitting in a Crazy Creek Chair with a good book...
     
  10. KayDubbya

    KayDubbya Paddler

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    That's good to know. I suppose the advice I'd got was coming from the perspective of a Wet Coast paddler, where too little rain is rarely a problem...
     
  11. ken_vandeburgt

    ken_vandeburgt Paddler

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    That's an important point. I figured it would be like pumping a water filter, which is a good deal more effort than you are suggesting. The thought of doing that an hour a day is unpalatable.

    Has anyone field experience with the katadyn desalinator pumps?

    I note Gillet used one on his Hawaii sojorn but I wouldn't rely on anything he did as 'normal' experience.
     
  12. Tootsall

    Tootsall Paddler

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    I've never seen one so this is just a "shot in the dark" but I wonder if it wouldn't be possible to set one up so that it "pumps" while paddling...either through a cord attached to the paddle or possibly something linked to a foot brace. Just a bit of "blue sky" wondering...
     
  13. MartinZ

    MartinZ Paddler

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    I met a couple of fellas in Baja a few years back who were trying to figure out how to do that. They had already given up on pumping while paddling - the swing arm needed more clearance than their cockpits allowed. However, they were experimenting with a system that allowed them to use their feet while seated on the sand. It was an early version and looked a bit rough, but worked ...
     
  14. newfie in Alberta

    newfie in Alberta Paddler

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    http://www.instructables.com/id/How-to-make-a-still/

    All you need is a simple water distiller....better known for making moonshine but the principle is sound. Should be easy to make a small scaled down still that you can use over an open fire. Not sure if you have access to firewood at your campsites.
     
  15. ken_vandeburgt

    ken_vandeburgt Paddler

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    I got interested in desalinators when I started gathering information about kayaking in Sea of Cortez off the Baja Peninsula.

    The area is desert. My guide book has lots of pictures in which a paucity of trees and therefore driftwood, is evident. So a wood powered still wouldn't work very well.

    But the thought of a still does bring on another idea ... does anyone know the vapour point of sea water in a partial or near vacuum?
     
  16. newfie in Alberta

    newfie in Alberta Paddler

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    Not sure how well it would work to carry a small still, and a propane stove to fire it?
     
  17. JohnAbercrombie

    JohnAbercrombie Paddler

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    I think it would depend on how efficient your still was....

    My 'back of envelope' calculation shows that it would take about 2.5MJ of energy to heat and boil a kg of water.
    Propane contains about 50MJ/kg- I'd probably halve that to take the tank weight into consideration.

    So, somewhere around 10% efficiency (not only in heating but also including vapour capture) would be the break-even point where you might as well carry water rather than propane.
    10% doesn't sound very efficient, but even that might be difficult to attain under 'field conditions'.
    Interesting question....
     
  18. dr_penner

    dr_penner Paddler

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  19. camshaft

    camshaft Paddler

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    Interesting idea except for the huge bulk, but I guess in comparison hauling a crap load of water isn't light.



    http://www.youtube.com/watch?v=TMCR-ie9H_w

    Found it funny when they said, compact, lightweight,?
    Height ....... 13 inches (Packed)
    Diameter... 7.3 inches (Widest Point at Rim of Base)
    Capacity.... 57.5 fl. oz.
    Weight...... 2.67 lbs. 1211.09 grams