rubber bladder at -50C 4

[Gore]

Hi,

I have a potable water bladder 20,000 liter made in rubber base material.
It has an inlet and an outlet. It lays on the ground and it shall work between -50C to 50C.
What should be the way to protect the water from freezing and / or becoming to warm to be drunk.
Is there a special material (plastic) that could be glued to the rubber bladder?


Thank you

Gore

 

[MikeHalloran]

Move it indoors.


Mike Halloran
Pembroke Pines, FL, USA

 

[MintJulep]

What to use to keep water from freezing at -50C?

Heat. Lots of heat.

By the way, where is this thing with this range of temperatures?

 

[RossABQ]

I have to believe someone wrote a temp spec for the materials of the system that doesn't apply to the completed assembly.

 

[Gore]

Hi,

The temperature applies to the completed assembly. The system will work most of the time in a location with temperature from -20C to +50C.

Gore

 

[iainuts]

You say it has to be drunk? I assume that means this is potable water, so nothing can be added to the water. If that's the case, the only thing you can do is to maintain it between the freezing and boiling point, which means it must be insulated from the low temperature (obviously it won't boil at 50 C).

You can use Mike's suggestion, which is to put the bladder inside a building or a separate container (ISO container perhaps?) that is insulated and heated sufficiently to keep it from freezing.

Another option would be to put it inside a tank that was insulated. You might consider using a used cryogenic tank since the vacuum insulation would certainly be much more effective than foam insulation and much more durable as well. Cryo tanks have the inner vessel made of stainless steel so it's a good match for your potable water. They're not cheap even used at $50 to $100 k, but I suspect you'll find that even a small, heated building will cost that much, and the cryo tank will be very easy to heat (through fill/return pipes) and extremely inexpensive to heat.

FYI: Rough order magnitude calculation of heat used for a 20,000 liter cryo tank with -40 outside comes to about 100 to 200 watts.

 

[Darken99]

Gore,

Is there a vent to let air in as the water is removed? If there isn't it will start deforming as water is removed. Therefor the insulation you apply to the outside would need to be able to deform or the water wouldn't flow out.

If it doesn't need to be transported, an underground tank is an option. It could be placed below the permafrost so it would not freeze in the winter and would be drinkable in the summer. It would be the same as pumping water from a well.

 

[Gore]

Hi,

The bladder being made in rubber is deforms when water is removed.
I am wandering what type of insulation material could be added on the bladder.
The bladder will be used outside.
Recirculation of the water combined with a good insulation or insulation with electric heating could be OK.

Gore

 

[Darken99]

I can not think of a way you will get enough insulation while maintaining your rubber characteristics. What about a solid insulation shell around the bladder that doesn’t deform. As the bladder deforms, the shell maintains its shape. To heat the bladder you could use the same type of system that a water bed uses.

You need to balance setup and operating costs of maintaining your temperature. More insulation less operating cost.

 

[DrRTU]

If the water is potable, you cannot add a product to lower the freezing point. I worked on a project that had a non-potable 26,000 gallon bladder under a casino. I would recommend installing the bladder below the frost line and building an insulated structure above or enclose the bladder in an insulated structure. You will need inspection ports and you should check the rubber min./ max. temperature requirements and make sure you meet the UV light requirements.