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svHyLyte 04-15-2013 11:17 AM

Making Distilled Water?
 
We use flooded cell batteries aboard our boat and routinely need to add distilled water to the cells, although only a few ounces every two weeks or so. While preparing for our next major trip I was contemplating storing a supply of distilled water in smaller water bottles to be stored in convenient nooks and crannies about the boat but I don't relish the idea of one leaking and thereby causing a problem. As an alternative, it occurred to me that I might simply be able to make the distilled water we need with our pressure cooker, and a length of food grade high temperature silicone tubing.

I was thinking that one could make up a length of tubing, coiled up and set in the galley sink filled with cold water, and temporarily attach one end of the tubing to the steam spout on the pressure cooker and the other through the cap of a water bottle. Water in the steam from the pressure cooker would be condensed in the tubing coiled in the cold water filled sink and forced into the collection bottle. I suspect that our four quart pressure cooker would allow us to generate a quart or two of distilled water from our domestic supply in pretty short order.

Anyone have any observations?

Brewgyver 04-15-2013 11:44 AM

Re: Making Distilled Water?
 
By steam spout I assume you mean the location for the safety vent. A couple of suggestions:

You would want to use a small coil of SS tubing. Silicone tubing probably wouldn't work very well and represents a serious safety concern. You want stainless because of its much higher heat conductivity. While silicone would hold up to the temperature (e.g. surgical silicone items are rated to be steam sterilized), it's more of an insulator than a conductor, so it wouldn't make an efficient condenser. More importantly, it folds and kinks too easily. If it gets folded while attached to the cooker, the pressure would rise rapidly, and the tubing would burst, spewing superheated steam and injuring anybody within several feet.

Other people have done this, for making distilled water and other distilled liquids. Others have used their household pressure cooker as a small steam generator for miniature steam engines, etc. I would suggest that you install a separate connection through the lid of the cooker, and leave the original steam vent to its very important job.

Faster 04-15-2013 11:52 AM

Re: Making Distilled Water?
 
I'd worry a bit about the low point of the sink 'condensor'.. and pushing through the condensate into the bottle.. also without a proper 'trap' I suspect the steam will blow through rather quickly. Also the sink water will heat up so will require some recooling, utlimately using a fair amount of water.

Can you set up a small heat exchanger with a circulation pump and use sea water as a cooling medium? or are you too tropical?

svHyLyte 04-15-2013 12:07 PM

Re: Making Distilled Water?
 
Quote:

Originally Posted by Brewgyver (Post 1016739)
By steam spout I assume you mean the location for the safety vent. A couple of suggestions:

You would want to use a small coil of SS tubing. Silicone tubing probably wouldn't work very well and represents a serious safety concern. You want stainless because of its much higher heat conductivity. While silicone would hold up to the temperature (e.g. surgical silicone items are rated to be steam sterilized), it's more of an insulator than a conductor, so it wouldn't make an efficient condenser. More importantly, it folds and kinks too easily. If it gets folded while attached to the cooker, the pressure would rise rapidly, and the tubing would burst, spewing superheated steam and injuring anybody within several feet.

Other people have done this, for making distilled water and other distilled liquids. Others have used their household pressure cooker as a small steam generator for miniature steam engines, etc. I would suggest that you install a separate connection through the lid of the cooker, and leave the original steam vent to its very important job.

Humm--Good thoughts. The vent I was referring to is the spout in the center of the lid that the Jiggler normally sits on. One really doesn't need much of any pressure at all as one only needs to boil the water, not super heat it as in pressure cooking eh? N'any case, I shall look into obtaining a length of copper tubing and rather than fooling with the Pressure Cooker, shall modify the whistle spout on our tea kettle, which holds about 1-1/2 quarts of water. A replacement whistle spout is inexpensive and already has a hole (for the screw for little handle/knob) that one could braze one end of the tubing to pretty easily. Our stove is quite close to the sink so a few feet of coiled tubing immersed in one side filled with ice-water would likely do the condensation well enough with the out put into a bottle standing in the other basin. (Think of all the water that condenses on the inside lid of a pot filled with boiling water for pasta.) It's worth a try, eh?

rockDAWG 04-15-2013 01:43 PM

Re: Making Distilled Water?
 
My thoughts:

1. If you batteries constantly need water, you may be overcharging your batteries.
2. Buy a gallon of distilled water and keep it on the boat is easier and cheaper.
3. If you have water maker on the boat, the water from the water maker is better than the distilled water.

Not sure the above meet your need. YMMV.

svHyLyte 04-15-2013 01:59 PM

Re: Making Distilled Water?
 
Quote:

Originally Posted by rockDAWG (Post 1016798)
My thoughts:

1. If you batteries constantly need water, you may be overcharging your batteries.
2. Buy a gallon of distilled water and keep it on the boat is easier and cheaper.
3. If you have water maker on the boat, the water from the water maker is better than the distilled water.

Not sure the above meet your need. YMMV.

I discussed the matter with the Tech's at Trojan that advised me that it is not unusual to need to add a few ounces of water to the batteries in very hot environments such as southwest Florida. We do keep a gallon jug of distilled water but we shall be gone for an extended period and may not have access to stores of distilled water during our travel. The Tech's at Trojan also specifically indicated that RO Product water is not an acceptable substitute for distilled.

YMMV?

jimgo 04-15-2013 02:29 PM

Re: Making Distilled Water?
 
I guess I'm still stuck with your fundamental issue - storage of water. It seems you're creating a fairly elaborate set-up, which will also have to be stored, to overcome storing something that you need. I appreciate the concern that a water bottle might leak, but if, as you've suggested, you were putting them in sufficiently small containers so as to make storage practical, wouldn't you also inherently be limiting the amound of water that can be spilled from any one container? In my mind, I'm envisioning you using the 12-16oz bottles you get at the grocery store for bottled water (where a case of water is $4). Depending on what you're storing around it, are 2 cups of water really going to be that big of a deal? In my mind, I'd be looking at buying a case of water and consuming it, keeping the bottles handy. If you want to be really anal, steralize the bottles, then fill the bottles from gallon-sized bottles of distilled water. Close the bottles, and put a dab of hot melt glue, some packing plastic (think cling-wrap), or packing tape on the outside to keep them from accidentally opening. Then stuff the bottles a) wherever they will fit and b) where you'll remember they exist.

Brewgyver 04-15-2013 03:02 PM

Re: Making Distilled Water?
 
YMMV = Your Mileage May Vary. A common web chat abreviation meaning it might or might not work for you.

I agree that niether desalinator nor RO system water should be used for batteries - use only distilled. RO does not strip out 100% of the mineral content.

The tea kettle contraption may indeed work, but I would still recommend SS tubing over copper, as I have no idea affect what trace amounts of copper would have on the battery electrolyte. If you do use the kettle whistle, make certain it can pop off of the kettle spout easily.

Re: previous post, no, you don't need nor want ANY elevated pressure, hence no superheat. I mentioned superheated steam in the case of the tube bursting. Not really superheated in terms of steam plant operation, I was using it for emphasis. A lot of people have no idea how dangerous steam can be.

rockDAWG 04-15-2013 03:25 PM

Re: Making Distilled Water?
 
Quote:

Originally Posted by svHyLyte (Post 1016808)
. The Tech's at Trojan also specifically indicated that RO Product water is not an acceptable substitute for distilled.

YMMV?

That is interesting. In the old days, the double distilled water is the gold standard of water used in the laboratory. Starting in early 80's RO and deinoized water is the standard in the ultra pure laboratory.

The double distilled water has a conductance of 11 uS/cm and 10 mg/L of dissolved solid while Type II and II water (RO ) has conductance of 1 and 5 uS/cm and no measurable dis-solvable solid.

I use Type I water daily which has conductance less than 0.057 uS/cm in our half million dollars Tandem mass spectrometers. I don't know what to say, but I trust my training in analytical chemistry more than I trust other's.

But in the real world, the life of a battery is fitly. A speck of dust is sufficient to contaminate the battery cell. After all batteries are not manufactured in a sterile and dust free environment. In other words, using distilled or RO water will make no difference in the longevity of the battery.

:)

rockDAWG 04-15-2013 03:30 PM

Re: Making Distilled Water?
 
Quote:

Originally Posted by Brewgyver (Post 1016831)
RO does not strip out 100% of the mineral content.

Really? Call up your local friendly state university and ask for the analytic chemistry department. :)


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