watermakers from Jetwashers

bazobeleza said:
Being a Yorkshireman, inveterate tinkerer and all round tight git, I have decided to build my own watermaker. I have investigated this on the net its well documented, I find I can build a 40gph one for for about £1500 but........ I then heard about a dutch lad selling plans for using a jetwasher for the base but of course he wants his palm crossing in Guilders before he'll send you the plans.

My question is has anyone recently made a watermaker using a Karcher or similar and how did it perform.

I have a Karcher K7 that is surplus to requirements and needs a new hose has a performance spec about 3.75hp motor and 550l/hr (120 gph) at 2300psi so I think with a different (lower) pressure regulator at 1500psi the output could be increased probably to around 200 gph and a 12% conversion rate would give a watermaker of 24gph capacity

The mechanics of construction appear to be straightforward high pressure plumbing. There does appear to be a problem buying the RO pressure vessels in the UK as I've not yet found a supplier.

Input power isn't an issue, cost however is. Any advice will be gratefully received particularly on sourcing the RO bits in the uk.
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You are quite right, they can be used, just feed the output to the end of a membrane with a needle valve on a tee. Then open the needle valve fully to start. Then slowly close the valve till you get the required pressure and pipe the over flow away. In essence that is it. The rest of the stuff is just controls to automate the process. I have a Kew Hobby stripped of the plastic case in the garage, I was thinking about doing something like this. Here is a pic of a similar one https://www.google.co.uk/search?ei=...j33i160k1.0.ZDVqIZYZe74#imgrc=w13XHn2GcvwaOM:

Its heavy but if you want it to play with, offers?
Stu
 
skipper_stu said:
You are quite right, they can be used, just feed the output to the end of a membrane with a needle valve on a tee. Then open the needle valve fully to start. Then slowly close the valve till you get the required pressure and pipe the over flow away. In essence that is it. The rest of the stuff is just controls to automate the process. I have a Kew Hobby stripped of the plastic case in the garage, I was thinking about doing something like this. Here is a pic of a similar one https://www.google.co.uk/search?ei=...j33i160k1.0.ZDVqIZYZe74#imgrc=w13XHn2GcvwaOM:

Its heavy but if you want it to play with, offers?
Stu
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Stu, you've just replied to a post which is more than 5 years old, made by a poster who hasn't even visited the forum for over 4 years. This is what happens when people resurrect dead threads rather than starting new ones!
 
pvb said:
Stu, you've just replied to a post which is more than 5 years old, made by a poster who hasn't even visited the forum for over 4 years. This is what happens when people resurrect dead threads rather than starting new ones!
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I doubt very much he will be visiting the forum, he's in a nursing home after a severe stroke. Beleza (Nauticat 44) is up the Guadiana and I'm informed is for sale.
 
pvb said:
Stu, you've just replied to a post which is more than 5 years old, made by a poster who hasn't even visited the forum for over 4 years. This is what happens when people resurrect dead threads rather than starting new ones!
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Blinkin heck!
Its that man again, resurrecting
Stu
 
You can get them cheap, from a company in the UK, based in Lancashire, cant remember the name of them, but a google search will find them, they have everything you would need. Found them, Desal supplies, Rochdale, great people to deal with.
 
When one compares the number of people on a forum to the number of people posting, you realize that most are just seeking info rather than giving it. Thus the number of new posts , or how long its been since a new one was posted, says nothing about how actively it is being used.
So, if one has new info which was not posted in the original discussion, then why should those seeking info on any subject have to weed thru a lot of similar threads, for the same info. Simpler to just add to what has already been posted.
I post just to pass on what I have learned in over 40 years of boat building, mostly full time cruising , living board , and building and designing steel boats.


pvb said:
Stu, you've just replied to a post which is more than 5 years old, made by a poster who hasn't even visited the forum for over 4 years. This is what happens when people resurrect dead threads rather than starting new ones!
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If it vibrates, you are getting air in. Hard on pumps.
A friend, who made them for a living, said pressure washer pumps are far more solidly built than those made for water makers .He said Italian made ones were the best, US made ones were the worst.
He said 80% of water maker problems were with electric drive.
I use a belt drive off my main engine. No electric clutch .Easier to just use a turnbuckle tensioner, when I put the belt on, for occasional use.
Any 3 GPM pump with ceramic plungers will work .I didn't have room in my engine compartment, so I mounted my pump outside it, and made a removeable panel to run the belt thru.

QUOTE=skipper_stu;6202354]You are quite right, they can be used, just feed the output to the end of a membrane with a needle valve on a tee. Then open the needle valve fully to start. Then slowly close the valve till you get the required pressure and pipe the over flow away. In essence that is it. The rest of the stuff is just controls to automate the process. I have a Kew Hobby stripped of the plastic case in the garage, I was thinking about doing something like this. Here is a pic of a similar one https://www.google.co.uk/search?ei=...j33i160k1.0.ZDVqIZYZe74#imgrc=w13XHn2GcvwaOM:

Its heavy but if you want it to play with, offers?
Stu[/QUOTE]
 
Brent Swain said:
The 540 Gallon per day filtre I use, fits perfectly in a standard ,2 1/2 inch sch 40 stainless pipe, 40 inches long.
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since the thread is resurrected,
may I ask why a SW30-2540 equivalent membrane only does 540gpd whereas Dow chemicals present it in their litterature as a 700gpd membrane?

just posted a similar Q on this thread

cheers

V.
 
Brent Swain said:
If it vibrates, you are getting air in. Hard on pumps.
A friend, who made them for a living, said pressure washer pumps are far more solidly built than those made for water makers .He said Italian made ones were the best, US made ones were the worst.
He said 80% of water maker problems were with electric drive.
I use a belt drive off my main engine. No electric clutch .Easier to just use a turnbuckle tensioner, when I put the belt on, for occasional use.
Any 3 GPM pump with ceramic plungers will work .I didn't have room in my engine compartment, so I mounted my pump outside it, and made a removeable panel to run the belt thru.

QUOTE=skipper_stu;6202354]You are quite right, they can be used, just feed the output to the end of a membrane with a needle valve on a tee. Then open the needle valve fully to start. Then slowly close the valve till you get the required pressure and pipe the over flow away. In essence that is it. The rest of the stuff is just controls to automate the process. I have a Kew Hobby stripped of the plastic case in the garage, I was thinking about doing something like this. Here is a pic of a similar one https://www.google.co.uk/search?ei=...j33i160k1.0.ZDVqIZYZe74#imgrc=w13XHn2GcvwaOM:

Its heavy but if you want it to play with, offers?
Stu
Click to expand...
[/QUOTE]

I was presented with one of the first Dow Corning membranes in the late 70s in Africa in an RO machine. We tried to put River Congo Water through it, the pre filters werent good enough, we were told later by the rep we should have used diatomacious (sp) earth as a pre filter. Also no iron in contact with the feed water.
Stu
 
Brent Swain said:
When one compares the number of people on a forum to the number of people posting, you realize that most are just seeking info rather than giving it. Thus the number of new posts , or how long its been since a new one was posted, says nothing about how actively it is being used.
So, if one has new info which was not posted in the original discussion, then why should those seeking info on any subject have to weed thru a lot of similar threads, for the same info. Simpler to just add to what has already been posted.
I post just to pass on what I have learned in over 40 years of boat building, mostly full time cruising , living board , and building and designing steel boats.
Click to expand...

I see no useful purpose in responding to a thread which finished and died many years ago, especially as many of the posters are probably no longer active on these forums. What's even worse - and I guess is the core of my objection - is that it's not terribly obvious from the forum software that it is a dead thread. As a result, people jump in and respond to early posts in the dead thread, without looking at the dates those posts were made. It would make much more sense, if someone genuinely does have new information on a topic, to start a new thread and to reference the dead thread with a link so that people can read the dead thread if they're so minded.
 
pvb said:
I see no useful purpose in responding to a thread which finished and died many years ago, especially as many of the posters are probably no longer active on these forums. What's even worse - and I guess is the core of my objection - is that it's not terribly obvious from the forum software that it is a dead thread. As a result, people jump in and respond to early posts in the dead thread, without looking at the dates those posts were made. It would make much more sense, if someone genuinely does have new information on a topic, to start a new thread and to reference the dead thread with a link so that people can read the dead thread if they're so minded.
Click to expand...
Many cruise these sites looking for info, and the recently posted info was not in the previous posts. The rest is just as relevant today for those seeking info as it was 5 years ago.
 
A designer who claims to have designed the steel Amazons, a Graham Shannon design.


Pete7 said:
American yacht designer of some merit who seems to prefer long keel traditional designs. Sadly lost his son to pneumonia a few years ago.

Pete
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Where the intake comes thru my hull, I put a 3/4 inch stainless T on. That let me lead one side to my primary filtre and the other to another ball valve . That lets me open the ball valve and push a dowel thru the thru hull , any time, in the water, to keep it free of barnacles.
 
Brent Swain said:
If it vibrates, you are getting air in. Hard on pumps.
A friend, who made them for a living, said pressure washer pumps are far more solidly built than those made for water makers .He said Italian made ones were the best, US made ones were the worst.
He said 80% of water maker problems were with electric drive.

This does not fit with my experience. Cat make watermaker pumps and pressure washer pumps. They are the same thing. The only item that changes is the cylinder head. They are made in three basic materials. Brass, s/s and nickel bronze. S/s and bronze are chosen for watermakers for their resistance to seawater corrosion. All other parts on the piston pump are the same.
In my experience 12v watermakers are the least reliable. Due to their small 12v motors they employ complex energy recovery sustems and automatic controls. The simplest reliable high output watermaker would be a cat pump and a direct coupled 220v 1.5kw motor. Little to go wrong. No automatic controls just a needle valve to set the pressure and a derverter valve to select water tank or test pipe. Apart from the drive motor (available off the shelf worldwide) there are no other electrical parts.
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