Ok Don! You win. Sketch first. Video later.
Have to go to sleep now. Midnight here. Tons of work at work this week.
A simplified sketch of major flows:
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I promised a boiler video. Here it is.
I expected 5 min when turning the camera off. It turned out 17 min. Don´t know how that happened. Time flyes when you´re having fun 
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Thanks Jan for the video. If a picture is worth a thousand words, your video is worth a million words!
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Hello JO,
A great presentation. The turbolator strips causing turbulence and enabling the heat exchanger to gather more heat was new to me and a very interesting event to keep in mind for future gasification adventures. The combustion tube shots were neat. Thanks for taking the time and posting this informative video of what I would call a bottom lit, downdraft wood furnace.
Pepe
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Thanks JO ,
Enjoyed the video very much 
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Exactly what I was looking for, I want to build one like this for my shop, thanks for posting! 
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Nothing to it. Just wanted to cheer you up with some glowing coals, snowstorms and all…
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That fire sure looks like it would make the house cozy. I heat by natural gas but we keep the thermostat low and at night while sitting around use the fireplace to raise the temperature a little. I know that my fireplace is probably the mouse inefficient use of wood. Insurance companies frown on wood furnaces.
What is happening over there this winter. I have never heard you say, but do you have a day job? I know you spend some time prepping wood for the winter. Are you able to work on you gasifier this winter.? TomC ( I will try to down load a picture and tell you a story about MY wood prepping this year.)
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Tom,
living in latitudes simular to Alaska and Siberia, winters are obviously dark. This winter was strange however, no snow and hardly freezing until christmas and then suddenly snow and around -30 C (-20 F) ever since. Today a couple inches of snow and a heat wave, -5 C (23 F).
I’ve worked full time for almost 30 years in a paper mill 10 miles from here. I work 3-shifts.( I tried another job for a couple of years in the middle, but that’s another story).
Yesterday morning I got home from working nights and I now have 4 days off. Working 7 in a row and 4 off all year around, 11 days vacation in the summer.
Days off, meaning work at home, of course. Same thing for most of us, I guess.
Apart from collecting a few bits and pieces of junk there has been no development on the gasifier since november.
But I promise that as soon as…
…temp is above freezing
…there is no rain or storm
…I’m not at work
…I don’t have to babysit granddaughter
…wife has no list (or she can’t see me)
…there are no visitors demanding coffee chatting
…no marragies or funerals…
…I’ll get the welder outside and plug it in.
I’m looking forward to your wood prepping story and pics.
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Nice informative video,i have a better view of the making in the gasifier type wood boiler heating designs,THANKS
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Jan-Ola
What happens if, at 90 C, the circulation pump was not working? (Eg in case of power failure)
Thierry
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Hello Thierry,
Primary air inlet will close by gravity and the fire will cool down in a few minutes. A little heat driven circulation still going on, just enough to keep the boiler from boiling.
I’ve had a few power outs over the years and it works.
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https://woodboilers.com/media/wysiwyg/Downloads/Product_Brochures/Solo_Plus_Brochure.pdf
I believe this is similar to what is being described.
Regards,
Garry Tait, Manitoba
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Hello Garry,
Yes, very simular. There are several commercial brands out there.
A word of advice though, if a may. Actually two:
- Don’t use a positive pressure system. Especially if mounted indoors. You risk CO and smell.
- Don’t use the “on/off” mode. You will tar up your system and eventually risk a chimney fire. Use a storage tank and full blast through out the whole burn.
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Hi Garry,
Thanks for posting the wood gasification boiler video. I picked up a couple more ideas for preheat. One I can semi try is pulling my inlet air through a shroud around my cooling tubes and in turn feeding that heated air into my present cyclone preheat arrangement.
My shroud would only surround the first 3 and hottest tubes. I’m sure I can reduce the size of my cooler as I can now hold my hand on the last 2 tubes as they are just warm during full operation. I know now that my firetube could be shorter, wasn’t sure about this when I started. Now to draw a preliminary design of a more compact unit. Fun! The single port air inlet (SPAI) feeds a circular manifold with 5 feeds to the nozzles.
Pepe
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Hey pepe, post some drawings and we could make some suggestion
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Very good work Richard. I’m piecing together a system myself, downdraft gasification, but aiming for continuous charcoal production and collection. Unfortunately the heating season is largely over, and it’s still in the shop. Like farming, there’s always next year… 
Jo: yes, I agree, a natural draft system is safer, and a sounder design, but otherwise essentially the same as what they illustrate. If pressurized air is introduced in the combustion chamber, that would be safer, and should eliminate smoke for start up, inducing a slight vacuum in the fire box.
Regards,
Garry Tait, Manitoba
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I highly recomend constant vacum mode. I always light up in downdraft mode.
Natural draft alone however has its downsides. Gloomy days or a cold chimney at lightup will often make you wish for better draft. Thats why I use a small squirrel fan on the chimney top. It’s fed by a motor dimmer from an old vacum cleaner. I can adjust to the vacum I choose.
If you want a maintenace free fan you can make your own ejector fan from two different size paint buckets. This way the fan always breathes only clean air and natural draft is still there with no restriction.
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A couple years back a DOW member told me that if you’re not handsome enough you can always brag about how cheap you are to get approval from the ladies.
Today I used some leftovers from gasifier builds to fabricate an ejector blower. Also to protect the motor I used flat roof tin which were leftovers from the rebak guards, which in turn were leftovers from when I built my porch roof 25 years ago.
Told my wife but I couldn’t tell if she was impressed or not 
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Hi Jo
I built an ejector a bit like yours. I am a little disappointed with its effectiveness. I can not create a vacuum sufficient to cause a torch in the combustion chamber of my boiler downdraft gasification . 
the vacuum seems to be too weak whatever the setting I make.
the chimney is 6 “in diameter and the ejector 8”. the fan is a 120-volt 12 ampere leaf-blower
Can I make a mistake somewhere?
I’m heating a greenhouse like Kristijan’s. the chimney is 20 feet horizontal vertical well 12 feet . can this produce too much restriction for an ejector fan?
Thierry
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