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Vacuum Pressure Solar Still


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This is a solar distiller for complete purification of water from any source, including sea water, grey / black water, or water which has been contaminated with heaby metals or other toxins which are not removed through Pasteurisation.

It consists of one metal drum (about 20 litres) painted white, another painted black (and wrapped in clear plastic for extra efficiency), two lengths of hose, a couple of two directional taps, a valve, a white board to reflect extra light onto the black drum and shade the white, and a small metal container to act as a boiler.

The process is:

  • Fill the black drum with water to be purified.
  • Set both taps so that the hose between the drums is open at both ends.
  • Have some water in the boiler, place candles or some other heat source on it till the water starts boiling.
  • Steam fills the two drums, forcing out the air.
  • When steam starts coming out the valve at the top take the heat off the boiler.
  • The steam condenses and pulls a vacuum in the drums, closing the valve.
  • As the drum heats in the sun the water starts boiling as the low pressure has dropped its boiling point to about 40-50 C.
  • The steam leaves the black drum and enters the white drum where it condeses into water. This can be actvely cooled with a wet cloth or similar.
  • The boiler will refill itself when the water level reaches it.
  • When enough water has collected in the white drum (you'll be able to see the level if you use clear hose), close the top tap and open the bottom one to drain the purified water into a container.
  • Close the bottom tap and open the top tap to suck water from the contaminated source into the black drum, refilling it.
  • Repeat. You may need to occasionally turn the whole device into the sun.


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Results / Field Data / Maintenance:

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