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Old 10-26-2009, 06:12 PM   #117
Ran D. St. Clair
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Join Date: Apr 2009
Posts: 212
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Toilet Testing

With some trepidation, I put my modified toilet together on the driveway for some initial testing. The bottom line is, it worked as advertised. I am not sure if it was thanks to my modifications, or in spite of them, but it seemed to work mostly fine.

I had it set up with a chimney of approximately the same length as it will use in the truck. It was up on blocks to allow inlet air through the fan in the bottom, and I had two 12V power supplies for electrical power. The propane was a standard 5 gallon tank with an off the shelf regulator and hose as sold for BBQ use. I also put a few cups of water in the rinse bag.

I started with about ½ cup of water to test the urine cycle. I pushed the button and it fired up as expected, the auger ran for about 20 seconds and then it fired up and ran the cycle for about 15 minutes. Nothing got hot at all. When it was done the outside of the insulated chimney pipe was only slightly warm. The auger input area was still dead cold, and slightly wet. I checked for air leaks around the toilet body itself and found a few tiny ones as expected. This is just fresh air blown into the toilet by the fan and not related to exhaust air. Mostly I was glad to see that my input fan was slightly pressurizing the toilet as I had expected.

Since it all went well, I decided to try a simulated poop test. I put in a paper liner, and dropped in a couple of slices of water soaked bread. (This was in my driveway after all.) I poured in a cup of water on top of it all just for good measure. I wanted to see the auger work so I slightly lifted the lid to peek under and found my first problem. The wet paper liner had wrapped around the auger and was just spinning, not making its way to the burn chamber. I poked it free just a bit and then restarted the cycle. This time it dragged the bread and paper back into the burn chamber leaving a few small crumbs behind. All of this makes me wonder if a paper liner is such a good idea.

The thing is very quiet, and it is sometimes hard to hear the squirrel cage blower or my fresh air input fan to know when it is burning. The ignition failed light came on for just an instant (meaning it lighted itself normally) and then it started to burn. There were about 4 burn cycles of about 8 minutes each followed by cooling cycles of about 4 minutes. The whole process took about 50 minutes.

I never saw any visible smoke or ash, only heat ripples from the chimney. There was no visible steam, though It was a nice day, about 75 degrees and dry, so I would not expect to see any. Throughout the waste cycle I would get occasional whiffs of something like toast. There was a light swirling wind in the area, so I was probably smelling the exhaust gasses from the chimney, not anything that would be noticed inside the truck.

With a waste cycle after a urine cycle it was pretty much up to full temperature by the end. I checked for heat all around and this is what I found: The outside of the insulated exhaust pipe was almost hot to the touch. I could hold onto it indefinitely, but it hurt a little. The outer plastic case was only slightly warm in the area above the fire box near the exhaust pipe. The inner exhaust pipe at the top was hot enough to burn me, but I could still grab it and hold on for a second without blisters. The exhaust gasses themselves were hot enough to burn me but I could hold my hand in the direct flow for a few seconds without getting burned.

I opened up the back access to the ash cleanout, but not the sliding door of the outer fire box. The sliding door and the outer fire box in general was hot to the touch, but I could still touch it for a second or two without getting burned. After the cycle was complete I opened the toilet lid and it was completely cold under the lid. The auger input pipe was warm to slightly hot near the fire box end but at the waste input end it was barely warm at all. There was enough radiant heat and airflow inside the auger pipe to dry it out, which is a good thing because dry stuff doesn’t smell.

After it was all done I shut it down to let it cool. Per the manual I shut off the gas first and was rewarded with an error light as expected. I then shut off the electrical power and disconnected everything. Several hours later I came back and it was almost completely cold. I opened up the back access to check for ash. The screw in plug came out perfectly clean and did not have any tendency for the threads to jam. I could see a few lumps of ash inside the fire box so I attempted to vacuum it out. There was one large lump about 3” long that was stuck to the bottom of the fire box and had to be broken free. The rest vacuumed out fairly easily, but the lump had to be extracted whole.

I examined the lump and found that it was fully desiccated, but not fully burned. There was still some structure of the toast inside. I don’t know if subsequent waste cycles would have broken it down further. I also don’t know if wet bread is a fair poop substitute. I do know that the fire box will fill up rather quickly if lumps like this aren’t completely burned over time. I am afraid the answer to that question will have to wait until it is mounted in the truck where I can do some real life testing.

In the mean time I am comfortable enough to go ahead and mount it in the truck when the time comes.

Be sure to check out all the various pictures under keyword "Stealth".

To be Continued…
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