Okay, so now the hot exhaust goes around the upper hopper area chamber wall and out the exhaust pipe to the atmoisphere and also through the slot opening into the hopper and the hot gases cooks the wood down. Any positive pressure in the hopper gasifier can now go out these slots and out the exhaust pipe also while the engine is still running? What about all the tary gooye smokey stuff going back into the exhaust system?
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Bob, the exhaust gases only heat the lower part of the wood storage tank above the hot zone, the upper part is water-cooled, where the moist pyrolysis gases circulate and dry.
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Oh yes sorry, I mean the lower part of the hopper wood area. So the hot exhaust flows out on and around the wood when there is a negative flow in the hopper and down through the firetube correct?
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I hope the sketch explains the structure of the gasifier.
download the image and enlarge the details you are interested in
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Thank you Tone for this excelent drawing, on how your gasifier is built. I will have to say no one has ever built a gasifier like this one ever before. So well thought out on the design and all. The hot exhaust engine gases do two things, it heats your incoming air to the nozzles and helps with the pyrotizing of the hopper stored wood above the firetube. Your welding skills are very good. Looking forward to more videos.
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wow. It is common knowledge my fab skills are non-existent, but that is next level fab with all those pockets in there. Lots of places for leaksā¦ Otherwise, I really like the concept. How did you build the inner cylinders for the air, exhaust and water?
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Bob, youāre probably tired of these kinds of videosā¦ 
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I will give some more data on the tractorās performance, which refers to the previous video:
-slope with a slope of 25%
-total weight of the tractor and load approx. 3.5t
- gear ratio 1:50
- driving speed 8 km/h
- drive wheels 12.4 R28
from this data we can calculate, taking into account the friction in the gearbox and the friction of the wheels on the macadam surface, which is probably 20%: - torque 124 Nm
- engine power 31 hp
if I also give the factory data of this engine:
- torque 133Nm
- power 35 hp
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I love the scenery. Although I sped it up to 2x speed because in my mind Tone isnāt meant to drive slow, even while pulling a wagon. 
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Tone, I am never tired of seeing a video of a tractor running on Wood Gas, or any other piece of equipment. It is all good to watch and see it happening. DOW.
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I miss Toneās old recording equipment where it made the tractor sound like a bubble machine. 
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Production of gas without oxygen,ā¦ this happens when the engine is idling after a heavy load, ā¦ overpressure in the gasifier.
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Interesting. All due to the exhaust heat recovery I guess. My rigs die emediately from starvation when I shut the gasifier air inlet.
I wonder what would happen if you decide to run the tractor on fossil fuel. Would the gasifier start charing any wood left in the hopper? 
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JO, I was not used to such gas expansion with the previous gasifier, although it also created overpressure inside for a short time in a similar case, but here this situation lasts more than 5 minutes, well, when I load the engine again, the gas quality decreases and it takes some time (about 20-30 seconds) to get strong gas again. Probably the temperature of the charcoal below drops, at the first opportunity I will try to lower the middle nozzle lower to the restriction opening, where the gas velocity is the highest, here I think that there is still a small negative pressure, which is a condition for fresh air to enter and keep the charcoal active,ā¦
Fossil fuels are no longer an option for use with this tractor, except for propane to help with quick starting and moving around the yard.
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Tone, l belive with the design you are having, with all the heat recovery, there is enaugh gas produced via pyrolisis to sustain idle. But this way, the wood is turned to charcoal wich can not burn as it doesent take in oxigen due to overpressure of gas. This charcoal acumulates. When high gas demand takes place, the gasifier first has a lot of charcoal to digest first, wich, in adition to the bed being cooled down, also gives hydrogen poor gas. When the heat starts to add some steam and pyrolisis gas the gas quality increases. My theoryā¦
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Today before starting I opened the lower cover and emptied the contents, well, it was mostly fine charcoal and ash, now the grate holds the charcoal well. I also dismantled the lower nozzle to see the condition,ā¦ everything is fine. As I said, I installed this nozzle lower a few cm above the limiting opening.
The tractor then worked for more than 2 hours, you can feel the difference, at idle the operation is more stable, even with a sudden high load the gas is more constant,ā¦ the theory works.
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I took some pictures from this afternoon, ā¦ cleaning overgrown areas, ā¦ this equipment makes the job a lot easier.
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What? Did you drop the fuel on the ground?
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JO, I donāt have any more space under the roof, so Iām storing lower quality fuel here, Iām sorry, but there are surpluses, thereās already about 10 m3 here,ā¦ 
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Tone, do you consider your screw crusher superior to a Rebak crusher or a flail crusher in terms of efficiency? I donāt want to start a debate, I simply want your opinion. 
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