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Inverted Down Draft Gasifier Prototype

 
pollinator
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Location: Western Washington
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Hey here is a design a buddy and I have been tinkering with a bit and I managed to steal a camera for a brief moment . I have all the stuff to scale this up to a large size but have decided to make a small portable one first. It is a pretty standard tube in tube made with junk I have salvaged from a foreclosed property. There is plenty more where it came from. I coupled this one together yesterday morning out of a piece of enameled stove pipe, a metal container for someones fancy booze, some 2x4 ends, a couple bolts, and metal piece from a dryer vent. I'm playing with a sliding flue to control airflow on the bottom

I am hoping someone here can advise on a good cheep (free? out of on site material?) way to gas seal the places where it joins. Currently short one set of appropriately sized bolt and nut so the center is hanging by a nail and off center - I'll get into town one of these days to get the 60 cent piece.

Fuel goes into center hopper and burns downwards. I will think about mass heat a slightly later date if this becomes a semi permanent fixture instead of a travel stove.

Hope images and writing are clear. First real rocket post here. Thanks all as always
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Landon Sunrich
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No takers?
 
gardener
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Location: Southern alps, on the French side of the french /italian border 5000ft elevation
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Landon, it doesn't seem even related to a rocket of any kind that i know. Pictures aren't that clear, and the principle behind is obscure to me. It could vaguely ressemble a sawdust stove.
 
Landon Sunrich
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Satamax,

Geez it took me forever to reply. Apologies - when I get frustrated with something I tend to drop it and move on to the next thing. Apologies for the poor pictures. I guess its not a "rocket" even though to me it resembles one. Its a wood gas stove. I've included a link to a 3 page PDF the first 2 pages are step by step instructions using a pop can and a bean can. The Third page is a diagram explaining the operating principles. I've built these small versions and am scaling up. It seems to me to be a very efficient burn which burns via pyrolysis so as to leave lots of char for the garden.

Link Here

Still looking for a good sealant recipe. I've monkeyed around with clay a bit but haven't found anything that works well yet.

Edit: I guess the technical name is an "Inverted Downdraft Gasifier"
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Principle of operation
 
Landon Sunrich
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Also, I just soak broken up twigs in old cooking oil for the starter. No need for the isopropyl and cotton balls
 
Posts: 244
Location: near Houston, TX; zone 8b
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There is a commercial version of this type of arrangement/design called a Wittus Twinfire.

To get a sealant which can stand up to the temps you may have to go with a commercial epoxy product.

I agree with Satamax, this is not a rocket stove.
 
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Location: Arcata, CA zone 9b
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When i visited All Power Labs (gasifier manufacturers in Berkeley) they talked about using stove cord coated with a graphite grease type substance for their high temp gasketry. They said it worked really well
 
Posts: 108
Location: Northern Ireland
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Hi Landon, Is this a passive design, ie do you have to force air through it with a fan etc, or does it go on its own? I've had a lot of success with TLUDs, even fairly small ones, running passively, using the height of the riser to pull both primary and secondary air through the system. I read somewhere that the downdraft can give you a cleaner blue flame burn - is this the case?
Thanks,
-Shane
 
Landon Sunrich
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Shane,

This is passive design. No moving parts (until I figure out my sliding flu air intake that is!). The guy who's egging me on is kinda an old hippie tinkerer genius who is quite insistent that the down draft is the way to go. Some of his stoves burn super super clean. Its like watching those intense blue gas rocket camping stoves. I haven't quite got one dialed in that well yet and my little can stove prototypes still burn an orange blue mix. I'll keep at it though, and hope that this one ends up the best one yet.
 
Shane McKee
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Thanks Landon - I do like the downdraft principle, as I understand you get a very nice clean burn indeed. It's the mechanics of how you get the downdraft though - maybe you could partially cap off the top? Looking forward to seeing your successful design in action
 
Landon Sunrich
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Shane McKee wrote: Looking forward to seeing your successful design in action



Man, me too. It's about time to get back on this one. But first I need to clear space. Grr.

So I don't speak Thai but I'm pretty confident after watching this video that I could do as well with suplies on hand.



I don't think I'd be satisfied with 'as well'. It look pretty smokey. I'd like to be able to run one inside (with a wall vent and fan to be sure). I know I've been taught NOT to burn the wood down to the end like they do here in the film but rather to cap the burn chamber once the gases burn off to cut off oxygen and switch it over to a slow charring burn.

Has anyone been fiddling with similar designs? Could one place a copper coil in that outside layer where they are packing the insulating ash or would one be better around the who sha-bang?
 
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