Ok here is an experimental kit. This is a smaller version of the kiln i started experimenting with except it now has a bell and lower enclosure. I cant and won’t market this as in indoor processor. But here I am using this for primary heat. In this application Ive slowed down the process via how much air it gets. However over a 24 hour period Im expecting around 10 to 20 gallons of ready to run fuel. 20 gallons will sustain my RV off grid system pr day without solar.
Note the chains and how they mount to the grate. The chains are longer and anchor to the side of the fire tube and then more to the center of the grate. The concept is as this is full of fuel and you rotate the grate the chains will twist against the fuel ever so gently. Any char that is ready to break off these chains will bind on it and it should break off and fall through the grate. I think this idea could be expanded on as well. Very simple and much less complicated than other ideas Ive had.
Hi Matt , I Love your simple design of your modified rocket stove charcoal making heater. (RSCMH)
After looking at the pictures for some time and studying them. It looks to me like you are adjusting the air flow with the square tubing lever. I see a glowing of charcoal to the left of the lever like a adjustable slot. It also looks like the lever is used to twist the chains and lift the grate a little. Looking down into the inside fire tube it looks to me, by the flash of the camera that the grate is a dome shape disk, so the charcoal moves to the edge of the grate and the bell part of the fire tube. When the chains hang straight the edge of the grate disk seals to the bell contour. When the chain is twisted it opens up a gap for charcoal to pass by and fall into the bottom charcoal barrel. While the charcoal is cooling because of the lack of air it gives off even more heat.
What can I say but, this is simply genius. That is if I am understanding it correctly. Heck, it genuine genius if I don’t understand it correctly.
Do you have something to keep the wood from falling between fire tube and outer barrel of the stove when loading it with the wood blocks, or is the gap to close for wood to fall between? I see that you also designed it so you can take it a part for cleaning. Good job Matt on this design.
Bob
Hi Bob, yeah the square tube is just to shake the grate. Next version the lower cabinet will be sealed better with an intake damper. There is a chimney damper on now that controls flow.
The grate is just a tic tac toe configuration it is flat. The ring with slots is what that is welded too. I have since closed off the slots as it gets enough air without those slots and helps with back drafting when I throttle it down.
Your visualizat8on of the grate maybe an improvement to add.
Yes you can drop fuel in-between the fire tube and bell. Just got be careful but no big deal if you do drop something in there. It will eventually reduce to white ash.
Yeah this is why I posted to get others to think. Here is my idea; now how can you improve it?
Looking at the picture I think I can see what you are seeing with the dome. That is an illusion, that is just the bottom of the unit you are just looking through the grate and seeing the bottom.
Hi Matt,
In taking a look at this, I see chunks of uncharred wood falling through the gaps in the grate. May I suggest making the grate in the shape of a tipi so the wood is forced to the outside of the tube. Also weld some 3/8 or 1/2 bar stock along the perimeter of the tube. When the tipi grate is rotated, the charcoal and/or torrified wood must roll up against these bars where the charcoal is knocked off. If the wood has not fully charred, it will stay there until it finally gets charred and then can fall into the waiting bucket.
How do you keep oxygen from finding its way into the five gallon bucket of charcoal below the grate? Does the five gallon receiving bucket move up and down to maintain tight contact with the pyrolysis chamber?
Gary in PA
Nice!! Yeah I have been thinking sort of along those lines. Yes I can create the grate like that.
Yes some fuel can get past it, but its pretty easy to sort that out. Generally if the pieces are larger, they are either just large pieces and fall apart or they are not fully chared. I just chuck em back into the fire wood bin.
The oxygen is limited in the catch bucket and char starts to drop the heat forces out the oxygen. What little oxygen does get in there is not enough to really reduce the char very much. Plus fresh new char is dropping on the existing all the time basically shielding it. So oxygen exposure is also limited. This actually helps when those pieces that didn’t fully reduce drop in there, The char existing in there will keep heating it.
As for sealing the catch bucket: yes I shim it up to the grate to help seal it. This is only because this is indoors and I need to throttle it down. So without doing this it will back draft. However if used outside you no worry about that and this thing will be wide open. If you are operating it like a piece of equipment you can make lots of char very fast with this. You just keep loading it and then removing the catch and replace it with another. You can run this all day long like this. The one in the shop is much larger and we can run that a bit hotter. If we are paying attention and shaking the grate we make around 20 Gallons a day on that stove. So far with this little one Ive made around 5 to 8 gallons a day.
when you reload the fire and there is burning wood at the bottom of the stove, a lot of smoke must come out of the loading door?
I love your simple ways of solving problems that seem complex to me
I will try to find some time to build such a stove for my workshop this winter. I need dry coal and in my snowy climate it is quite difficult to make good coal in winter. thank you for sharing your ideas.
Thierry in Québec
Yes it does, you only want to load when its burned down to keep that to a minimum. I think if I add a second flu damper at the top, it might suck out the smoke. So only when you plan to open that door, you open that top damper up and then shut it back off once the door is closed.
