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DIY Water Distiller
I have been interested for some time in building a Water Distiller, as it can be used to purify water and to desalinate water. Both would be handy in a survival situation. Keep in mind that distilled water can also be used in soap making, for use in steam irons, and to refill lead-acid batteries.
The process of distilling water is called Thermo-Distillation, which means by heat. It removes the broadest range of contaminates of any water purifier, to include viruses, bacteria, cysts, and heavy metals. Real handy in an area like New Orleans, Louisiana, when they had their water badly contaminated. It is also my understanding that distillation can remove some radioactive materials (radionuclides), but not all. However, my thought is that even though you have removed some from the water, they do not disappear. Instead, they accumulate in the distiller and you will have to deal with them, and they are now in a concentrated form. How do you handle what is basically radioactive waste? I'm not sure, but this was not my reason for building a water distiller.
The concept of the Themo-Distillation is pretty simple. You place contaminated or salt water in a pressure cooking device. As the water boils, it creates steam. The steam travels through a tube to a coil that is placed in cold water. As the steam enters the coils, it condenses back to water that is now pure distilled water. Maybe an over simplification, but that's how it works.
I have seen various types of home-brew distillers in various articles and videos, but I had a few prerequisites for the distiller I wanted to build. I wanted it to be built as cheaply as possible using available materials and a little shop skill. I wanted it to be sturdy so it could be moved around and stored and not have it break apart. I wanted to be able to set it up easily for use, and then taken down easily for storage. Lastly, I wanted the pieces stack-able so it could be easily stored.
After some planning, it was determined that we would need a Pressure Cooker, Cooper Tubing, some brass fittings, Silicone High Temperature Tubing, and a Two Gallon Bucket with Lid. My wife, Denise, and I started ordering parts. Although we have a couple of pressure cookers, we didn't want to use one of our good Swiss ones, and wanted one that we could dedicate to the project. Denise was able to find a Presto 6-Quart Stainless Steel pressure cooker on eBay for $28.00, a real good find. I was able to find the Copper Tubing, fittings, and 2 Gallon Bucket with Lid at Home Depot. The only thing left was the Silicone High Temperature Tubing, which I was able to find at a Home Brewing Store.
This is the Pressure Cooker we found on eBay for $28.00.
I chose 3/8" O.D. Copper Coil for refrigeration because it was in a coil, which would make it easier for me to reconfigure the coils into a smaller coil when the time came. The coil provided me with twenty feet in length, which I felt should be more than adequate.
This shows how the Copper Coil came off the shelf at Home Depot.
Both the Copper Tubing, and brass fittings to attach the tubing to the top of the pressure cooker, had a 3/8" outside diameter, so I needed the Silicone High Temperature tubing with an inside diameter of 3/8". I figured I needed about six feet.
This is six feet of Silicone High Temperature Tubing purchased from a home brew shop.
When we finally had all the parts in hand, I headed for the shop to start making the Condenser Coil for the Cooler Tank. I had a two gallon bucket that had an inside diameter of 8" at the bottom and 9" at the top, and the height was 9-1/2". I wanted the condenser coil to be smaller than the 8" bottom diameter, and the coil that came out of the box started at 11". I began carefully reworking the coil so that they would have an outside diameter of approximately 7". My plan was to use two quart frozen juice bottles in the center to assist in cooling, and this size coil would allow for that, and still be an inch or so away from the walls of the bucket.
When I completed the coil, I wasn't happy. When you set the coil up on end on the bench, gravity came into play and the coils would slowly start collapsing down on themselves. I wanted the coils to stay a predetermined space from each other and do so in a permanent manner. I also didn't want to suspend the coil from the top of the bucket, as it was my feeling that they would still wiggle around, and I wanted this thing rock solid.
Back at the drawing board, I determined that if I made some type of frame where each coil could be attached at a specified distance, and somehow attach this frame to the bottom center of the bucket, it would be permanent and solid. Looking around I found some Punched Flat Bar made from zinc coated steel (available at Home Depot) and I thought this might just be what I was looking for. I was able to bend the flat bar into a "U" shape that would fit around the outside of the coils. I made sure that when I bent it, the holes on one side were slightly higher that the holes on the other. My idea was to use strong zip-ties to secure the coils to this "U" shaped frame. With the holes offset, this would ensure the coils continued in an upward spiral, which is necessary when the steam is condensed back to water and needs to flow down the coils. If one coil faces in an upward angle, or is higher that the one across from it, the water will not flow down, and this could also cause pressure to build up back to the pressure cooker.
The idea worked as planned, but it would not set upright in the bucket. So I riveted a cross bar, made from the leftover Punched Flat Bar, on the bottom of the "U" shaped frame and this solved the problem. The Condenser coil was now ready to mount permanently into the cooler bucket.
This is a top view of the completed Condenser Coil.
This is a side view of the Condenser Coil attached to the "U" shaped frame.
A bottom view of the Condenser Coil and the "X" shaped frame to keep the coil upright.
A view of the Condenser Coil next to the two gallon bucket it will be mounted in.
I needed to mount the condenser coil in the two gallon bucket in a manner where the outlet tube at the bottom would protrude from the side of the bottom of the bucket, and the inlet tube at the top protruded from the top side of the bucket. I didn't want the inlet tube to stick up above the top of the bucket because for storage, I wanted to be able to put the lid on the bucket and store the pressure cooker on top.
It was a little work, with some twisting and spinning, but I was able to get the outlet tube through an angled hole I made in the bottom side of the bucket. I then made a slot in the top side of the bucket so the inlet pipe could slide down into it. This required that I use a piece of Kydex to hold the inlet tube in place. This I simply riveted to the upper side of the bucket. Once everything was in place, I used a quick-set two-part Epoxy to both secure, and waterproof, the inlet and outlet pipe to the bucket. I still had a little wiggle, so I mixed up some more Epoxy and secured the "X" shaped frame to the inside bottom of the bucket. When it dried, nothing moved and I finally had what I wanted. I tested the Cooler Tank to ensure that it was watertight and it did not leak around the inlet or outlet tubing. It was watertight and ready to go.
This is a side view of the Condenser Coil mounted in the Cooler Tank.
This is a top view of the Condenser Coil mounted in the Cooler Tank.
This is the Inlet Tube of the Condenser Coil mounted in the Cooler Tank.
This is the Outlet Tube of the Condenser Coil mounted in the Cooler Tank.
Once the Cooling Tank was complete, we ran a solution of warm water and vinegar through it just to make sure the inside of the copper tubing was clean. It was then rinsed with more warm water.
Next, I had to remove the original pressure valve from the top center of the pressure cooker lid, as it was too small. I had to drill the original hole larger so I could replace replaced the original valve with a brass fitting that provided me with a 3/8" O.D. outlet to accommodate the Silicone High Temperature Tubing. Note that the brass fitting is not a pressure valve, just a straight through tube for the steam to escape. Pressure cookers can be dangerous, so you don't want pressure to build up in the cooker, so make sure that the straight through tube remains open and not clogged.
This shows the original Pressure Cooker lid with a pressure valve that was too small for the tubing I was using.
This is a close-up of the original valve on the Pressure Cooker lid.
Once the original valve was removed I enlarged the original hole to accommodate the brass tubing.
This shows the modified Pressure Cooker lid with the new, larger fitting for the 3/8" tubing.
A close-up view of the new "pass-through" valve.
This is a view looking straight through the copper tube attached to the lid, from the inside. As you can see,
it is not a pressure valve, just a straight tube. This prevents the build-up of pressure in the pressure
cooker, which is not what you want.
Once all the parts were completed, it was time to test the system. It should be noted, that prior to completing the project, we had filled two, two quart juice bottles, with water and placed them in the freezer. They would be used in the cooler tank to help keep the water cool.
The pressure cooker was set on the left burner on the stove and filled, two-thirds, with water. The cooler tank was placed on the counter to the right of the stove, which left an unused burner between the pressure cooker and the cooling tank. I knew the cooling tank would get hot once we started, so I didn't want to add any heat by setting it next to a hot burner.
I now cut a piece of the silicone high temperature tubing that would fit from the top of the pressure cooker to the inlet of the cooler tank. Another piece of tubing was cut to fit from the outlet of the cooler tank to a two quart bottle we placed on the floor below the cooler tank.
The pressure cooker was heated and as the water began to boil you could see steam starting to enter the tubing above the lid. At this point we placed one of the frozen bottles in the cooling tank and filled it with cold water. We watched the process and it continued with steam being sent to the cooler tank inlet, the steam was then condensed back to water which exited the outlet pipe, and ran down the tubing to the bottle on the floor.
Water frozen in a two quart bottle for use in the cooling tank.
Now I must warn you that watching this process is like watching grass grow. The water in the cooler tank started to heat up and we had to replace the frozen bottle with another one. After the second one melted, we just used cold water in the bottles. Keep in mind that the cooler tank does get hot as well as the inlet and outlet pipes, so be careful that you don't touch them.
This shows the system setup on the stove and counter.
This is another view showing the "catch bottle" on the floor.
A closer view of the two quart bottle set on the floor below the cooling tank to collect water.
It took two and one half hours to almost fill the two quart bottle on the floor. It was midnight at that point, so we shut the system, down, and went to bed. The bottom line is the system works for its intended purpose, but again, it is a slow process.
To store the system, we simply place the inlet and outlet hose in zip-closure freezer bags and store them inside the pressure cooker. We have rubber caps to place over the inlet and outlet of the cooler tank, as well as the outlet on the lid of the pressure cooker. We place the lid on the cooler tank and then place the pressure cooker on top. It can now be stored on a shelf until it is needed.
Water Distiller stacked and ready for storage.
In an emergency you would have a viable means to purify contaminated water and desalinate salt water. It is easy to set up and easy to store after use. The system is easy to build without a lot of technical knowledge required. Again, keep in mind that distilled water can also be used in soap making, for use in steam irons, and to refill lead-acid batteries.
However, the process takes time, which necessitates the use of a lot of fuel. It also requires a continued supply of cold water to keep the cooling tank cool. If the system could be setup outside near running water, you could use a small rocket stove made from bricks which would utilize only small pieces of wood. But it would require a continuous monitoring to keep the fire going and collecting water.
Because of the need for fuel and cooling water, I am now looking into building a Solar Distiller, which will utilize the sun for the heat, instead of fuel. When that project is completed we will report back with another article. Until then, we will continue testing the above distiller.
We hope you enjoyed this article and will help support our efforts by checking out our products. As always, Be Prepared To Survive!
Copyright © 2014 by John D. McCann