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Old 03-07-2008, 00:43   #1
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no energy input water maker

okay, we all think water makers need power. but there is a way around it. cost less than 200 bucks.

okay i guess i have you attention, so here we go. first go buy one of theseProduct Information Error Page

then take your good old fashioned collaspable 5 gallon water container, and enough tubing to go from the top of your mast down to the saloon or some where. fill the water container, hook up the tubing and hall it up the mast attached to your sail line. then take the tubing ( currently pinched off ) and hook it to the input of the RO filter. take the discharge line and put a shut off valve in it, and just crack the valve to get a good steady drip. run the discharge line to the bilges or over board. then figure out how many times a day you have to refill the container, you could run a tube up using a small bilge pump to refill it. but it should take a few hours to drain all the way. figure it will make 1 to 2 gallons of water per fill.

okay the reason it works is the home units only need 20 to 60 psi to work. a 40 foot mast will create 32 psi. also the concitrate does not need to flush as fast as they say, but the membrain will not last as long, but at 50 bucks (for the membrain) or so for a few months ( in housed rated 3 to 5 years ) is 5 to 10 gallons a day worth it

now there are ways to clean the install up that i will leave to you. this was tested on a web site i go ( non boating ) to and the guy was getting 3 gallons a day running the tubing from his second to first floor

edit also running the discharge line back up a few feet increases the pressure on the membrane but keeps the water flowing
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Old 03-07-2008, 00:47   #2
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there are other ways to do this too. one is a 10 gallon air tank modified with a fill fitting and an out put line. fill it with 8 gallons of water then use a bike pump, air compressor etc to pressurize it to 60 to 80 pis.

air tank like this btw HUSKY 11 Gallon Carry Tank - KT110003AV at The Home Depot
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Old 03-07-2008, 02:44   #3
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The "one of these" link does not work.
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Old 03-07-2008, 02:47   #4
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the link worked for me before now i am getting an update page

simple put it is a GE reverse osmosis system for under sink use in you house... cost 160
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Old 03-07-2008, 03:04   #5
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The "one of these" link does not work.
Neither do 80psi home R/O water treatment units (for desalination).

An R/O Desalination unit exerts a high pressure on the high concentration side of the membrane (input), usually 30–250 psi (2–17 bar ) for fresh and brackish water, and 600–1000 psi (40–70 bar) for seawater, which has around 350 psi (24 bar) natural osmotic pressure which must be overcome.

The pressure required is dependent on the concentration of the salt solution on the reject (concentrate) side of the membrane.
Sea water systems at 33,000+ PPM run at about 800+ PSI.
Under sink systems at home usually run at 50-70 PSI.

Saline Water Concentrations:
Fresh water - Less than 1,000 ppm
Slightly saline water - From 1,000 ppm to 3,000 ppm
Moderately saline water - From 3,000 ppm to 10,000 ppm
Highly saline water - From 10,000 ppm to 35,000 ppm (seawater)
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Old 03-07-2008, 03:35   #6
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a 40 foot mast will create 32 psi.
Sorry that doesn't compute. 40 ft of water column = 17.34 PSI. Will never push water through a salt water RO filter
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Old 03-07-2008, 03:46   #7
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Sorry that doesn't compute. 40 ft of water column = 17.34 PSI. Will never push water through a salt water RO filter
EXACTLY.

One foot of water at 62 degrees F = 0.433 PSI.
To find the pressure (in PSI) for any height of head (in feet), multiply the head by 0.433.

40 ft. head x 0.433 = 17.32 PSI

It takes a minimum of 600 psi to reject seawater. Most R/O desalinators operate at over 800 psi.
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Old 03-07-2008, 04:22   #8
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I totally agree Gord. Mine runs at 1000psi
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Old 03-07-2008, 06:06   #9
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According to the laws of irreverserable thermodynamics, the pressure required is exactly proportional to the concentration of whatever it is in the water you are trying to clean up. The under-the-sink units are dealing with concentrations of a few hundred ppm at most while seawater is 35,000 ppm. Nature says there ain't no free lunch.
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Old 03-07-2008, 14:45   #10
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okay so my pressure was wrong, opps i just quickly did the math wrong

as for the system working, if you say it wont then i will not convince you other wise. but i know what i have seen. which includes a system which you fill with dirty water, poor in a sugar consentrate on the fresh side and it gives 1 gallons per day with NO pressure. it was even tested with urine. let me see if i can find the link for it

edit here is a system that uses no pressure to desailenate water The World's Purest Salt Water Filter - HTI Main Website

if this system can use a sugar liquid to get salt water thru the membrain, you dont think some simple head pressure will work, just not at 10 gpm, more like 10 gpday. we are simply talking about enough water to drink not for showers, deck washing, etc. if i was doing a blue water crossing, on a sail boat i would be happy with 10 gpd for no energy input.
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Old 03-07-2008, 15:54   #11
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Yeah yeah, if the pressure was wrong, why did you tell people to do it? Obviously you've never seen it work, nor tried to go sailing with an extra 40+ pounds of dead weight up at the masthead. Filling a system with 'dirty water' isn't at all the saline as desalinating seawater.

Posting a link to the Seapack is pretty useless too. That's a one-shot emergency desalinator, it won't work for long. And it DOES REQUIRE ENERGY INPUT, it requires $100US of energy for ONE SHOT. Whether it takes gas, electricity, or money, it still requires "energy" up front. I can buy 100 gallons of water, in bottles, for the same money. That's way more effective.
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Old 03-07-2008, 16:17   #12
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i have seen this work, i just had the math i used for the mast height vrs pressure wrong. the test i saw the guy did it with one floor worth of head pressure ( he had the water on the second floor of his house ) so figure he had 15 feet of head pressure max

and your right i have not sailed with 40 lbs of weight up on the mast either. if it makes you feel better say you can use an old soda keg and use air pressure to supply pressure for the membrain. the air pressure can be from lots of sources, a bike pump, a compressor, or a co2 bottle. yes the compressor needs power so rule it out. a bike pump is people power, which is already on the boat any way. co2 is cheap and can be found any where. a small bottle like a 20 oz paint ball bottle would pressurize a 5 gallon keg many many times to 50 or 60 psi

we are not talking about tons of water here we are talking about enough water to live on, nothing more

also your right you can buy 100 gallons of water for 100 bucks but then you have to store 800 plus pounds of water on your boat, which at 10 gallons a day is only 10 days of water. which if you dilute salt water 50 % ( which is safe but nasty tasting ) you can get 20 days.

using the keg and paint ball air bottle, and a reverse osmosis filter would weigh less than 30 lbs, and give you several hundred gallons at 5 to 10 per day.

but i guess no one wants to think that anything less than a 2000 dollar system that can produce 10 gallons a min will work at all. i guess i will have to scrounge the parts up to make one

as for the seapak it is just showing pure water can move across the membrane at less than several hundred psi from a salt water source. and in my original post i did say the membrain will not last for the several years speced by GE for use in a house
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Old 03-07-2008, 17:24   #13
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edit also running the discharge line back up a few feet increases the pressure on the membrane but keeps the water flowing
That would REDUCE the pressure differential on either side of the membrane, not increase it.

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as for the seapak it is just showing pure water can move across the membrane
That's not pure water, it's sugar water. Expensive sugar water.

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but i guess no one wants to think that anything less than a 2000 dollar system that can produce 10 gallons a min will work at all. i guess i will have to scrounge the parts up to make one
I'd LOVE to see a cheap system that will work. You should definitely put one together and try it. That's how inventions are made. Getting an idea and trying it. You may find that people in here are wrong and it WILL work. You may find that people in here are right, and it won't. But in that case, maybe after getting hands on experience, you may find a way that will. So, go for it.

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Old 03-07-2008, 17:44   #14
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Like Dan says, go for it. Regardless of what you think you've seen--it hasn't been found yet. If someone invented a $200 desalinator that could provide water for four people (that's four gallons, minimum) per day, it would be red hot news and we'd find out about it sooner rather than later.

If your friend has done this and you've seen it--you are missing a huge opportunity, lock up your patent rights quickly and come back with a working demo system. It will be a sell out at twice that price!
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Old 03-07-2008, 17:47   #15
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Ok Scotty, this post started with an idea. It was debunked. Now you are desperately trying to talk it into working. Get out on the salt water and hoist the sails.
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