Ernie Wisner wrote:I try to make sure the burn tunnel is as short as possible. if i could get it on all the systems the burn tunnel would not be more than a third of the heat riser height. if you have no problem with a barrel column in the house. by all means make the heat riser a but taller I think ours at the moment is 44 inches. burns like a champ. the other thing i would suggest is that instead of pipe you use brick for the heat riser. steel pipe will burn out and while thats not a bad thing if you have your perlite and clay mix right it is annoying to clean out flakes of burned steel. Sides i found out you can get 1/2 fire bricks and they work a treat.
Well, usualy i'm not too bad at welding, and i thought about an insulated riser RMH pocket rocket mix.
Well, imagine, i would start with a stainless tube, quite tall, with another tube outside, keeping the perlite or else around the first one. Normal heat riser you'd say. Then i would weld a top chopped gaz bottle, off center to thoses tubes, so the wall of the gaz bottle, cut all the way to the bottom round part would just make it to the center tube of the heat riser, taking advantage of the curve to gently bring the flame to the inner tube. The gaz bottle would be the feed, and the shape between the two, bottle and heat riser, would be a cressent. There would be no burn tunel as such. Then i would make a colums of small barrells, to accomodate the heat riser, but i would make a slanted recess, to accomodate the feed tube. See what i mean?
Is there adverse effect of having no burn tunel in a rocket stove?
the burn tunnel is involved in the mixing of the smoke and air (one of the several reasons an all steel RMH doest work correctly). why dont you just make a pocket rocket? How big is the space you are heating?
I am confused as to what you are wanting to do. if you use steel or iron as the liner to the heat riser on an RMH it will burn out. stainless also burns out eventually but it takes a long time unless you push the system way over normal burn temps. masonry doesn't burn out but it takes bricks that these days are expensive new or you can use salvaged brick. cement does not work either even refractory cement cant handle 2500 to 3000 degrees in the hot zone of the heat riser for long. If you need a fast radiant heat system a pocket rocket works like a charm you will still burn the steel off the bottom of the feed tube but its easy to replace.
Folks please remember these stoves get really really hot. the barrel temps are low because we design them to be so you dont have to much danger in your house but thats still 500 degrees in the first third of the barrel.
Making a small change can give you a stove thats glowing red hot every time you light it. a bit more of a change and you can get it to burn white hot a touch over that temp the barrel fails and you have a live fire in your house. the system as its designed is as safe as we can make it and still heat the house. other configurations as i pointed out can get you better heats but the RMH is designed to heat a thermal mass not just act like a Franklin stove. if you want a thing like a franklin stove them look at the pocket rocket. its an easy build stove made out of pipe and a bucket, oil drum, barrel, culvert etc.
Well, i don't want a pocket rocket. What i like is the low exhaust temps and no smoke of the rocket stove.
The first one i built, http://www.permies.com/t/10367/stoves/Cyclone-rocket
Has weird features. But i use real thick steel. sometimes more than 1/4 inch. I haven't goten the feed tube to glow more than orange. No yellow yet I think in my design, the bottom gaz bottle acting as a cyclone protects the heat riser from burning too fast. Next one will have a heat riser made with the same tall gaz bottle which serves me of radiator for the moment. Burn tunel and feed tube gonna be gaz botles too. They're all in the 3 to 5mm thickness range. I don't know if the next one i make cyclonic or not. What i thought, in making what i described earlier, is to get the smallest footpring rocket i could. I'm trying to make an easily reproductable, long enough lasting stove, which has low exhaust temps, burns clean, and has the best removal of heat from exhaust gasses.