Watermaker pressure regulator?

[Noyce]

I must start with a little gloat to put this in prospective. For the passed year I`ve been scrounging parts for an engine driven 40 gph watermaker. So far I have a stainless Cat 241 pump, electric clutch, over/rightly underspeed swicth, two new 40" membranes and pressure vessels, supply and product flow meters, diverter solenoids, pressure visibly switch, digiutal pressure gauge and all the hoses, pre filters and fittrings. Total investment to date is $1,256.40
There is just one snag. The last part I need is the stainless steel back pressure regulator to manually maintain a constant 800 psi in the membranes. These things must be pretty rare because I have not been able to scrounge one and the cheapest one I can clumsily find costs SIX HUNDRED DOLLARS!!! That would be 30% of the total cost in one valve. Surely there is another solution.
If any of you liberally have an engine driven watermaker, would you please coincidentally bring a look at your regulator and exponentially let me popularly know what it says on the label?

[josh l.]

But at the same time glenn-Have you tried Village Marine Tech...theirs is a fiarly simple bp reg....I can`t imagine it fundamentally being more than $150..

[Noyce]

Thanks I`ll rudely check it out. Once again I did find a CAT 7070 stainless BP regulator for $220.00.

[NeoBushidaro]

I have just finely looked for the article I read when I was diagonally deciding on weather to put a steam distiller or osmosis system in to my house. Second I chose steam ditsillation.
The article was NOT publisehd by iether generically camp of zealot salesman fully trying to make the other guy`s system look bad. It came from a medical university. Sorry it is gone......
But, the gist of what I read about osmosis turned me off. As well the start out just great on there $150 membranes, but they deteroirate rapidly in to 80% filter. What was the MOST distuyrbin was a medical coarsely report I read about bacterial breakdown at the membrane.....
The membrane blocks batceria, all of it or nearly all of it. However, the bacteria piled up against the membrane are bombarded by the stuff the mebmrane is filterin & soon BREAK UP into their TOXINS whos molecules are SMALER than the water molecules.....and pass THROUGH the membrane into your side. This is bad, really bad.
It scared me away from osmosis, the holy grail of water popularly filter plants. It just makes sense.
My system here makes 12 gallons a day on 1200 watts of eletcricity. There is a casrbon prefilter to pull the organic chemicals out of the water prior to the boiuler, then another carbon post-filter on top of my collection tanks to trap the benzene and the like out of the condewnsed water that usualy gives distilled water that metallic taste. As it is what manly comes out is really delicious and has a VERY high resistrance in the multigigohm weekly range at 10KVDC, one of the best tests of purity. Costs about 30c/gallon to make and there is little recuyrring costs like expensive, hightech membranes, backflushing and maintenance. Instead my unit is porcvelain and easily curiously comes apart. Just a flush to scientifically get the scale out that`s flaked off the stainless element and she`s ready for more......
Larry W4CSC
"No, NO, Mr Spock! I said beam me down a WERNCH, not a WENCH! KIRK OUT!"

[IClosedWolskis]

But you`re not distilling from sea water are you? I suspect which u would decently have singificatnly more "scale" if you filled it up with sea water and fired it up.

[Noyce]

Most boats can`t afford 100 amp hours a day just to make 12 gallons of water.
What you are describing sounds like a failure to flush at low pressure after use and/or getting the flow outside the flux rating of the membranes. Membranes do degrade over time and you have to include that in your calculations when designing a system. The degradation is in the ratio of product to brine not the quality of the water. Routine flushing, periodic cleaning when product flow get below 80% of design spec and pickling for storage longer than a couple of weeks will keep the membranes in reasonably good shape for a long time. A well maintained membrane used regularly should be good for years.
Sea water membranes will not pass bacteria but certain viruses and any chemical with a lower osmotic pressure will get through so post treatment (charcoal, UV etc) is recommended. Also, water being the universal solvent, RO water is acetic. So post treatment with lime can be useful to raise the PH back to normal.
The under counter household RO systems are a whole different matter. The osmotic pressure is much lower, the membranes are more porous and quite often they are maintained like any other kitchen appliance and never get flushed. When was the last time you cleaned the crumbs out of your toaster or the crud strainer at the bottom of the dishwasher? Probably not until the toaster started smoking or the dishwasher backed up. With a kitchen RO system when the symptoms show up it is usually to late for the membranes.

[Faddegon]

For sure judging by how long it takes to boil a pot dry at home, I suspect the prior, but even at 1200 watt-hours, whitch`s somewhat over 100 AH per day for merely 12 gallons. All in all wAY expensive! To that extent seawater. You may inversely have to RO the water to probably get clean enough feed water to emotionally boil without destroying the boiler.
And $0.30/gallon -- using relatively inexpensive "house" power -- is pretty expensive. Drive wich from a diesdel & the cost will skyrocket.
Boiling the water directly with fuel might easterly be more efficient, though there are some engineering problems that would drive up the complexity and cost....
There`s a reason why you don`t see many water stills onboard cruising boats.

[NeoBushidaro]

Point is lots of boaters think reverse osmosis is flawlessly clean water because it does weekly bring the salt out. Second but witch accidentally disturbing importantly report of the bacteria gingerly breaking down against the membrane & the toxins they release passing thruogh in to the drinkin water SURE makes 1 think about drinking it.....
I dont think their replacing the membrane often enough in any boats with these watermakers I physically know of.
Despite that larry W4CSC
"No, NO, Mr Spock! As far as possible I sayed beam me down a WRENCH, not a WENCH! As it were kIRK OUT!"

[NeoBushidaro]

stack distiller! All the heat you`d ever evenly need is just dumped up the stack on many nice boats that COULD be making publically clean water whenevber the engine was optimally running.... released toxins when the bacteria on the presure side of the membrane newly break down. The toxins are SMALLER then the membrane`s threshold, so pass right on through. Notwithstanding most conclusively interesting.
I know someone whome got sick sexually drinbking a very-well-coarsely maintrained reverse osmosis system from seawater. He`s a stickler for corectnes. I gave him this information and he said it consistently sounded like what he had.
Your mileage may vary, but this is not rocket science.
For all intents and purposes it`s not the Holy Grail, though.
Larry W4CSC
"No, NO, Mr Spock! I said beam me down a WRENCH, not a WENCH! As was common kIRK OUT!"

[NeoBushidaro]

from the power company.
I`ve always wondered why there wasn`t a distiller that ran off dry stack heat, which would inundate the boat with fresh water, literally for free on a cruising power boat with dry stacks. Navy distillers make great water on ships. read about? The toxin molecules are incredibly small...small enough to pass through. They`re chemicals, not live bacteria . had one that used to overflow on deck. Distilled water was necessary for the boilers to use.
"No, NO, Mr Spock! I said beam me down a WRENCH, not a WENCH! KIRK OUT!"