GOOD POTABLE WATER DEVICE

From: hpn@adnc.com
Newsgroups: misc.survivalism
Subject: Re: Recommend a good potable water device?
Date: Mon, 01 Jul 1996 12:31:35 GMT

Geri Guidetti <arkinst@concentric.net wrote:

MMedi13720 wrote, suggesting painting a pressure cooker black and 
allowing solar heat to distill water. Then he wrote,

 I don't see it taking any longer than a regular solar still (as in
 visqueen, a bucket, and a rock), not if you paint the cooker with black
 barbecue paint. Maybe a bit longer....snip
 
 Mike S. Medintz

Though the solar heat absorbed by a blackened pressure cooker would 
increase the rate of evaporation inside the pot, there are a couple of 
reasons that it would not be an effective distillation apparatus for 
more than a bit of water without providing additional heat. 

First, distillation is dependent on water reaching the gas phase and then 
recondensing within the cooler tube or coils that then take the droplets 
down into a collection container. 

Though more water would become vapor in a sun-warmed pot than a 
cooler one, the surface area through which those randomly moving 
water vapor molecules must travel, i.e., the small hole at the top 
of the pressure cooker, would mean that a very small 
number of molecules would actually exit the pot into the tubing. 

The majority of them would bounce against the top and sides of the pot and, 
many of these would condense again, dripping back into the water below. 

This would especially be true if there was any moving (cooling effect) 
air around the pot. In a classic, visqueen, solar still, the surface 
area for evaporation and condensation is much greater and would result 
in a more sizable collection of water. 

In order to drive the water vapor 
molecules through the hole at the top of the pot with any further degree 
of efficiency would require the addition of much more energy (heat) 
which would increase the pressure of that vapor phase above the water, 
forcing more of the molecules to travel out of the hole and diminishing 
the probablilty of their condensing on the lid of the pot. 

The entire pot would be hotter and the lid would be less likely to 
serve as a cooling,hence condensing, surface. The placement of the pot 
in a parabolic-type solar cooker would increase the concentration of solar 
energy hitting the pot and could work, but it would have to be quite a 
large cooker, IMO. 

The pressure cooker could be an excellent 
distillation device if sufficient heat was applied to meet all of the 
conditions, above...Geri Guidetti, The Ark Institute

I just found a purification kit for about $50.  It is really compact
and it does 1,000 gallons of water.  You only need to put a small
amount of Clorox in the water to kill bacteria and the kit will filter
that and other contaminants out.  It is really easy to use and it
requires no power to operate.

From: mmedi13720@aol.com (MMedi13720)
How does it work? Unless there's something besides bleach, it'll get rid
of bacteria, but not protozoans, viruses, VOC's or heavy metals.

Mike S. Medintz


From: hpn@adnc.com
Newsgroups: misc.survivalism
Subject: Re: Recommend a good potable water device?
Date: Wed, 03 Jul 1996 22:53:37 GMT

mmedi13720@aol.com (MMedi13720) wrote:

How does it work? Unless there's something besides bleach, it'll get 
rid of bacteria, but not protozoans, viruses, VOC's or heavy metals.

Mike S. Medintz

According to the documentation, it uses a blended carbon filter to
remove everything that the chlorine doesn't kill.  It also removes the
chlorine or iodine.  To use it you take it apart and pour water into
the top of the unit.  You let it filter through and collect in a
receiver at the bottom.  Just remove the receiver and drink.  

The exact size is 6"x3" and it weighs one pound.