Anyone Tried Making your own Watermaker?

[jongleur]

General TT911 pressure washer pump

I was under the impression that the high pressure
pump must be a special sort of bronze, so as
to not poison yourself.

Anybody know? I can't remember, but it wasn't
just a regular high pressure pump. Seemed
pretty important at the time.

[Cheechako]

AFAIK it just has to be an alloy that doesnt degrade from salt water. Cant be any worse than Cu pipes commonly in a house.
You can get a Honda powered 2500psi pressure washer new for under $300, membrane and cannister and a few details and bob's your uncle? would this work? Probably less than $1k for the whole thing...

[hellosailor]

"Lets stick our heads together and make it work!"
The immutable laws of physics often are confused with illusory and limited sightings of them. However...

The USSR "lost" track of some 2000 strontium piles, used in aeronautical navigation beacons scattered across their hinterlands. These are basically a lump of radioactive material that emits substantial heat as it decays, which is used to generate electricity. But you can just as easily use the heat from any radioactive mass to boil water and distill it. Voila, all you need is a ball of something like that, sourced from the black market or otherwise, and you'll have a steam distillation water maker on your boat, good for somewhere between ten and a hundred years.
Probably already for sale on Alibaba.com.

I don't see electricity and electrical failures being a stopper, compared to the possible problems of "I broke my ___ when we capsized" or got thrown across the cabin.

On the other hand...those guys in Homeland Security, they have this real attitude about private possession of strontium piles. Kinda like the guys in Ghostbusters who were warned not to pull that switch...

[weavis]

Originally Posted by hellosailor

The USSR "lost" track of some 2000 strontium piles, used in aeronautical navigation beacons scattered across their hinterlands.

Well thats it then....... I'll start looking.

[socaldmax]

Originally Posted by weavis

So the average required pressure for forcing water through the membrane to remove sodium chloride is 68 bar.

hmm.

I think, I will have a look at the pump mechanism of an espresso coffee maker. If water can be de-salinated when hot, then that is a mechanism that will do it. If you boil water and use the heated water pressure through the pump, then 100 bar is easy to achieve.

hey! I like coffee. Sue me!

Yes it would require a heat source. Perhaps gas rather than electric. And it will make 8-10z a minute.

If you're going to boil it, might as well distill it and skip the whole filter thing. Navy ships boil water for onboard use, but they have plenty of heat to do it.

[socaldmax]

Originally Posted by Zanshin

Weavis - remember that only a small percentage of that hot water actual gets to become sweet water, most of it is bypass water and is ejected overboard! So a typical 20% recovery ratio means you've heated 80% of your water for naught.

That doesn't apply to distillation systems. If you're willing to scrape the sea salt out of the pot occasionally, you could boil all of the water out. Just take a 6 qt pressure cooker, attach a 25' stainless tube to the lid and coil it up. As the steam passes into the tube, it condenses back into hot water and exits into a clean jug or vessel. If you use a 5 or 6 gal SS stock pot and leave a gal. or 2 of room temp water in it and the coil is submerged in the water, it will condense just fine. It's just going to take X number of BTUs to boil X number of gallons of water. Waste heat from an engine would be nice to use, but it might be a lot of work making a heat exchanger for distilling.

[a64pilot]

It takes a tremendous amount of energy to change water to steam, unless you pull a vacuum on it first

[StuM]

Originally Posted by a64pilot

It takes a tremendous amount of energy to change water to steam, unless you pull a vacuum on it first

Good point, latent heat of evaporation of water is nearly 3 time that of alcohol. so it takes nearly three times as much energy to distil a gallon of water as it does a gallon of moonshine (and a higher termperature).

[socaldmax]

Originally Posted by a64pilot

It takes a tremendous amount of energy to change water to steam, unless you pull a vacuum on it first

Exactly.


Maybe we've been going at this all wrong. We need to use a 6 qt heated, sealed vessel, a condensation tube into a larger, 5 gal sealed vessel, with a vacuum pump hooked to the lid. Pull a vacuum on the larger vessel, which in turn pulls a vacuum on the smaller heated vessel, add a little heat and we get steam at a lower temp, like 100*.

[Lepke]

I have my own water maker made from components. I like my water taste better than any city water I have experienced. Some commercial fishermen make their own system with just a low pressure membrane running off engine driven salt water pump. Higher fresh water rates take higher pressure. You can make a 12v low pressure system for a few hundred dollars. You need a pump that delivers 50+psi. 80 psi is better. Membranes and housing can be bought on Amazon or Ebay. Filters add lifetime to your membrane and can make the water taste better. Membranes are designed for the water conditions, salt, fresh, brackish. Fresh water membranes only take about 94% of the salt out. A salt water membrane takes out about 98%. Some people just use fresh membranes and tell me they don't taste the salt.
My system uses a 20, 5 and 1 micron sediment filters and two carbon filters before the membrane and a post carbon filter and UV light after. Currently I use two membranes. You can get a starter system for about $150 on Ebay but would need a small inverter to run the UV light (that kills bacteria that gets past the filters/membrane) and a 12v pump that does at least 50psi. That would give you 50+ gallons/24 hour day. That's when the membrane is brand new. I have a power boat and have room, so run 4.5x20 filters and almost never have to change them when in the ocean. Bays and rivers are why I have so many sediment filters. I sized my system so I can make enough water at anchor by running the generator for an hour/day.

[colemj]

You cannot get sea water passed through an RO membrane at 50psi - at any flow rate. The osmotic pressure of sea water is ~400psi, which must be overcome for reverse osmosis to occur.

If you are in fresh water only, that is different, but your advice on parts for someone looking to run in seawater is incorrect.

Mark

[SV THIRD DAY]

Originally Posted by Dangerous Quote

Some people just use fresh membranes and tell me they don't taste the salt. .

I have to jump in here and correct one of the most DANGEROUS things I hear people say all the time about marine water makers and that is the idea/myth that if your water tastes good then it is safe to drink. We cruised with a couple in Mexico that were doing the “taste test” verification of their water maker. Their Basil started to die and their cat wouldn’t drink the water…but it tasted fine to them. When they finally tested the product water it was over 2500PPM!

The internet is abounding with conflicting information and flat our rumors, but the human taste buds can taste salt anywhere from 3000-5000PPM (depending on what source you want to believe). The World Health Organization says that 500PPM is the safe drinking water level and other sources say closer to 800PPM is ok. Your water maker could be producing water below your ability to taste the salt but still damaging to your body. If you are not checking your product water with a simple $25 hand held TDS meter then you are risking damaging your kidneys!

I've seen it all folks:
0.1GPM pumps feeding a clogged 40" membrane (too little flow for membrane surface area, but the guy he bought from told him it would work)

A 4.5GPM pump trying to be driven by a 0.5Hp motor (too much pump for the motor to drive...but it was a great price on Ebay)

Brass pumps that saved money that looked like Swiss cheese (look at the holes in the pump head valve seats in the photo below). This photo is for all the "Brass will work experts" out there. Will Brass work...sure it will...but not for long as this poor guy found out when their pressure washer brass water pump died in the South Pacific...

[hellosailor]

"but would need a small inverter to run the UV light (that kills bacteria that gets past the filters/membrane)"

The UV-C light will keep critters from growing in your freshwater tank, but the desalinator membrane itself should not be passing any bacteria or virus unless it has been punctured.

[Fix]

You can find 12 vdc UV sterilizers
Engine driven HP pump is the key to cheap,simple,reliable desalination onboard.

[socaldmax]

I'm in a different field (VHF race radios) but I see all of the same things Rich is talking about here. Guys want to try different radios, want to buy the radio and have me modify/program it for them, all in an effort to save less than $10. LOL

I explain to them that I started selling these radios because I paid too much the first time, for an inferior radio. I've done the homework, looked at everything in that segment of the market, and the one I sell is the best deal, in addition to being more powerful and cleaner sounding.

I really appreciate Rich (and others) spending the time to come on here and explain the mistakes and misunderstandings people are making, it's not as simple as it sounds to make something reliable in a salt water environment under that much pressure. A lot of things can fail, and they will when you least expect it.

Rich, I'm on a few Yahoo groups, trying to learn about different brands of boats, I figured it's the best place to hear about problems, whether isolated instances or systemic. Interestingly, whenever the topic of watermakers comes up, your name gets mentioned with the highest of recommendations for your honesty and customer service. You simply cannot buy that kind of advertising, and when I read those spontaneous endorsements it sticks in my mind, you have to really work hard to please people to that level of satisfaction.

I've driven 180 mi RT to a customer's house to diagnose his electrical problems that he blamed erroneously on the radio. I've shipped radios back to the mfr at my cost and gotten them repaired under warranty even though it was expired, driven 300 mi RT on several occasions to deliver packages at no charge, yet AFAIK, I've never received the kind of glowing endorsements you have gotten. I've just chalked it up to "that's how people are these days, no positive feedback for going above and beyond" so it's very encouraging to see that some people DO give excellent feedback for excellent service.

I'm just in the wrong business with the wrong clientele. LOL