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Post by Donkey on Aug 31, 2008 13:08:21 GMT -8
You don't really need to have an upwards run in the bench.. It does no harm and perhaps to provide a more even heat to your bod. having it closer to the surface as it looses heat along the way may be a good strategy. If you cheat the barrel forward it will provide a larger gap in the front, encouraging the heat to flow through there more than the back.. The barrel could even touch the heat riser, effectively closing off the very back to flow. A heat reflector may be a good idea, though it might not be worth the extra work.. You just gotta figure that one based on yer own circumstance. I am curious to know how much such a thing would help, so if you do it, let us know.
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Post by chronictom on Aug 31, 2008 19:53:18 GMT -8
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Post by Donkey on Sept 3, 2008 13:02:23 GMT -8
Ah.. I advise you lengthen your heat risers. The Aprovecho style Rocket Stove is designed for countries where cooking on the ground is the cultural norm. If you plan on using this stove technology for heating ESPECIALLY, you need to think two and a half to three feet plus in height.. Benches with long runs and down-flows, etc. need the motive force a tall heat riser can provide.
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Post by chronictom on Sept 3, 2008 13:07:24 GMT -8
How long can the feed tubes be?
As in, if I were to drop the feed tube to riser through the floor (about a 2 foot drop) I could easily get the height for the riser, but the feed tube would also be that much longer.
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Post by Donkey on Sept 4, 2008 1:47:06 GMT -8
Real muscle comes (in these stoves) when there is a good deal of vertical separation between the cold air intake (assuming it's the feed box) and the top of the heat riser.
Sinking the thing in the floor could help somewhat, though longer feed tubes just complicate matters and make things hard to light. Some kind of under-air system could be just the ticket.. errrrr... peterberg's rocket bell has my gears churning...
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Post by chronictom on Sept 4, 2008 6:48:13 GMT -8
Just going by what I've been reading so far, I am curious about something.
If you have a secondary air feed, what stops the flames from creeping up the fuel in the feed tube?
If the only intake is the feed tube, it's sucking the air down past the fuel into the flames and out, keeping the fire at the ends.
no?
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Post by Donkey on Sept 4, 2008 17:31:44 GMT -8
Yep! I've not really found a solution that I actually like to this.. Using the feed tube as the air intake keeps it simple and it works. Looking at peterberg's stove got me thinking.. Not a surface thought, so I can't really spell it out yet.. I can feel movement down in the waters, perhaps an answer, perhaps more questions.. Dunno yet.
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Post by chronictom on Sept 5, 2008 11:54:32 GMT -8
Well, one of my thoughts when I seen his, was that the firebox was wrong (no offense peter), and it would be better to have a feed tube that is on the side that you can stick to vertical drop to feed, straighten out path to the riser, then go with the double bells on top?
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Post by peterberg on Sept 6, 2008 2:22:25 GMT -8
I'm a bit puzzled with your reaction, Tom. Of course the firebox is very wrong from the normal view. The goal was to have a firebox to load a complete batch in it, lit it on top and walk away.
The normal configuration is such that someone has to be around for a couple of hours to tend the system. Because the whole thing has to have the same 6" of whatever throughout, the feed tube is relatively small compared to the volume of fuel to burn each day. I wanted to avoid that, so I've segregated the pyrolysis of the fuel from the burning of the woodgas.
And to have the feed tube outside the bell is the same disadvantage. The open feed tube need to be the same as the burn tunnel etc. Keep in mind, the plan I am working on is a consumer product. Maybe only the rocket/fire chamber for sale, with detailed drawings of the rest to be built by a handy amateur. Could be done, I do think. The bell construction itself is very simple.
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Post by chronictom on Sept 6, 2008 7:16:31 GMT -8
I don't know why you would be puzzled, I explained my thoughts quite clearly. But I will flesh them out if you wish...
Steel door, steel grate, right off the bat, are not things I have laying around.
Secondly, your stove is closer, and moving even closer, to a masonry stove and not a rocket stove. At least, to the way I take it.
To me, the beauty of these stoves (rockets) are that they are mostly built with things you can find laying around by people who have nothing to start with. Your idea (although as I did say numerous times, I do like it), is moving towards (as you just said) a commercial type unit.
As for loading it up and walking away, that is what an airtight stove is for, I have two of them, no need to build anything. Yes, efficiency could be improved by adding bells and whistles (pun intended), but you would never make up for the energy that you put into it making those modifications.
I have sitting in my kitchen, a double walled airtight, CSA approved wood stove with an attached blower. I can load it up and let it run with only one of two fillings a day if I wished to.
Before I am done here, I will have at least 6 living buildings, as in buildings people live in, perhaps more. So when I judge if something is right or wrong (from my point of view, which is why I said I meant no offense to you), it is based on whether or not it is something that is relatively simple to build, and most importantly cheap.
The bell (and double bell) part of your design are a great idea, they add performance without adding much to the costs (if you weren't using commercial bricks), and as such can be incorporated into my plans.
The firebox, and ash box and under air vent, all involve much more work then is needed to get what I see as a very good performing stove already.
As for,
"Keep in mind, the plan I am working on is a consumer product. Maybe only the rocket/fire chamber for sale, with detailed drawings of the rest to be built by a handy amateur. Could be done, I do think."
EVERYONE, with a little coaching (such as the rocket stove book, and/or this board) can build the whole thing. Without buying either the firebox or the plans to the bells from you.
Out of curiosity... what cut of the profits are you sharing with donkey and the boards once you have finished picking his brains and selling what you learn?
(p.s., people should learn to accept statements such as 'no offense'... because when you don't, it almost always gets worse)
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Post by peterberg on Sept 6, 2008 8:43:58 GMT -8
Tom, you wrote among other things:
"The bell (and double bell) part of your design are a great idea, they add performance without adding much to the costs (if you weren't using commercial bricks), and as such can be incorporated into my plans."
Thank you for the compliment. You are welcome to use any of my ideas. They were published for that purpose.
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Post by chronictom on Sept 6, 2008 9:30:15 GMT -8
You're welcome, I meant it sincerely.
And even on the rest of it... I wasn't dissing the idea's themselves. You definately have something that could be a great thing, it is just getting away from the... 'here, go build this with crap laying around' part that I don't like, and thats just because I pride myself on being a cheap bastard... lol
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Post by Donkey on Sept 6, 2008 13:00:48 GMT -8
I like the "laying about for use" method myself as well.. Though peterberg's ideas can be used there as well with some modification. I can do fairly simply with cob and a few bits and pieces just about everything I've seen in his model so far..
I am glad, Peter that you have published your ideas here. I certainly don't do this for any money (at least not here on these boards) and the "open sourcing" of ideas just turns me on. Rocket Stoves are public domain and IMHO should remain so in their entirety. Let's keep it open, flowing and free.
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Post by chronictom on Sept 10, 2008 20:38:56 GMT -8
how long did you let those first two risers dry in the bucket before pulling them out?
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Post by Donkey on Sept 12, 2008 8:59:49 GMT -8
Just long enough to jell a bit and not slump. Depends.. The top one I took out too early and it deformed a little. In hot sunny, dry conditions, maybe all day, pop em out the next morning. Maybe a couple days..
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