Hello Goran, here are the sketches of the hot zone, first a sketch of low loads, then medium and finally full power. The red area is colored where oxygen enters the carbon oxidation process, this enables the formation of CO and the conversion of other gases, here the coal glows white at a high temperature. Full power actually forms a ball of glowing area which is pushed down by the flow of gases.
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Very good drawing of the two hot lobes of charcoal, a top and bottom shaped like donuts, then both burn together, then one big round fiery ball of hot charcoal.
It looks like the bottom nozzle holes need to be small enough so they can not supply to much air at higher vacuums on the gasifier. To much and it would go into a over pull on the gasifier or turn into what we call a heart effect burning up good gases that have been already produce from above.
I would think there should be at least 8 in. or 20.3 cm of charcoal area around the bottom nozzle holes to make gases at high vacuum loads. To large of nozzle holes and the air will burn though the charcoal reserves.
I like the idea of a bottom nozzle holes having a air regulating valve of some sort.
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I dare not talk too much about the WK style, Mr. Wayne proves daily how well it works even with large air nozzles. I very much agree with Goran, who explains that with a small load, the air descends along the wall, where it is forced to go towards the middle before the restriction opening, and here it meets the glowing coal. The white-glowing layer of charcoal must stay below, slightly above the limiting opening, which, however, begins to expand upwards when needed. I think that the size of the pieces of wood is important for this style, which must be quite large, so narrow fire hoses are not suitable for this style, as the pieces of wood would get stuck. But if you intend to use small fuel, it is necessary to make a shorter (shallow) hearth. Here I am attaching a sketch for the comparison of two gasifiers, …
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Thanks Tone, that is the picture i imagined, therefore my thinking was faster jets reaching closer to the middle, would help, for half charred wood don’t reach to deep in a shallower firetube 
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And: please don’t leave me alone, i look forward to all input on this 
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I don’t understand what the darker red arrows are showing. Is that the moisture/tars?
Assuming you can’t change the draw (like on a generator), does this mean smaller nozzles (faster jets) are needed to help stop the center from collapsing and allowing the “half charred” wood to get too close to the exit?
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Those are concection currents that drive the hopper wood drying/pirolisis
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Goran, thank you for the invitation to the meeting, I will not delay, I will start a constructive debate right away…
JO and I tried a hearth with two levels of nozzles, both of us this construction worked out quite well, but when we look at the left sketch, we see that we need to keep glowing coals near the restriction opening, if we were to start making such a WK hearth now, I would install nozzles of small cross-section at the bottom, approx. 10 cm above the restriction opening, and slightly larger ones at the top. I think that this would be a guarantee to keep the coals glowing below, I would also install a system for shaking the grate. Such a heating pipe will not be picky about the shape and size of the fuel. 
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Excellant depiction Tone.
Overlook by most not-users is the factor of Idle levels of activity; versus High Loading levels of activity.
The active material core must expand and contract for this. Yet not let your dark-arrow upper gases bypass the core.
A significant diffnerce I over the shoulder have seen with WK users is the acceptance of large amounts of grate spilled char to keep their beds active and renewing. Freed up ash marching through out of the active core area.
Then like the WWII Imbert era pictures at a performance stopping point dumping; scraping it all more-or-less out: sorting; and putting the larger char chunks back in.
Your concept on yours is completely different. You want to convert up all possible chars in-place.
Ha! Ha! As Goren stated you putting air in so low is a NO-NO eye opener.
Could this be done on a larger demand V-8 system??
An unknown until proven.
But certainly should be able to be expanded up to a Volvo sized I-4.
Regards
Steve Unruh
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Yes Steve, that NO NO eye opener is got me thinking on my two not completed WK builds. Right now if can I find a way to put air in right below the restriction opening in the larger Charcoal reserves area. It needs to be 7" above the grate? With a regulated air at this point, humm it just might be possible, but adding to much air at a high vaccum pull could over pull the now active Charcoal reserves and start burning up the good gases pass the grate. But this would sure clear out a tight char bed going down the road, no need of a grate shaker.
With the flat grate and tubular cage and center nozzle with holes, it still needs 8" minimum to the edge of the grate. 17 " diameter grate. This can be done in a WK low part of the gasifier area. With a larger side hatch door for servicing and ash clean out.
I love it, when there is something new under the sun has been discovered.
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Here is a sketch of a WK fireplace with additional nozzles, if the fireplace had a diameter of 35 cm, the distance between the lower nozzles would be approx. 25 cm and they would be placed 10 cm above the restriction opening, let’s say that I would use 8 nozzles with a cross section of 4 mm at the bottom and 10 at the top nozzle with a cross section of approx. 6-8 mm. I would imagine that this unit could produce gas for a 2-4 liter engine without fear of tar gas getting through or a “hot leak”.
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I agree. I still run that same Mazda setup - 6 years in a few months. SS firetube welded to a mild-steel air-preheat shroud and housing, no grate, no gasifier cleanout door and only a cyclone to collect all the debrie. Lot’s of NO-NOs - but it works.
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On my WK firetube with 12" or 30.5 cm diameter and 12 nozzles. I have about 9 1/2" or 23.1 cm to a 7 1/2" or 19.0 cm restriction opening. Then from there down to 6" or 15.2 cm plate the opening that is 8" or 20.3 this is the bottom of the gasifier this hold the restriction pipe. The grate is about a 1" or 2.5 cm below that total firetube is 18 1/2" or 47 cm. Long standard size WK Firetube with a grate on chains hanging below it.
It seems your firetube would have to be a little longer.
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Bob, I had the feeling that the WK pipe is much longer than its diameter, for example in the ratio 4:3 = length: diameter. Goran expressed his desire above that he would like to have a gasifier that is not picky about the size and shape of the fuel, so it is good to have a wide pyrolysis area so that there is no clogging and as few narrowings as possible, so I will build a gasifier in one diameter from top to floor Trying double the size of the hot pipe turns out to work, but I have a feeling JO won’t be building this again. Why? Because when there is a greater load, the coal burns below and a void is created? The reason? Too large cross-section of the nozzles below, too narrow area, so the new fuel does not touch, too narrow area above for the pyrolysis process ??? Hmm,… if you look at the sketches of the Joni gasifier, it uses a very shallow area, similar to what I drew in the last sketch, and forcibly exhausts the high vapors, which at the same time allows for more intensive pyrolysis, which spreads upwards, the charcoal supply, … WK the pipe has a great potential to use different fuel even at low load, it is only necessary to adjust the size and position of the air openings, if you weld M16 nuts below and screw in allen screws 3-4 cm long with a 4mm hole, you can make an experiment, these openings you can easily plug if it doesn’t work well but I guarantee you won’t do that…
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Now we’re talking, Tone
I like it, can imagine it’s functioning principle.
I would add one more gas outlet, to spread the gas draft more evenly (just my old ideas)
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And since the comparison base is to a WK system . . .
Those with the HWWT book and access to Premium side full system pictures can appreciate the produced gasses flow going from mid-vehicle back to the rear bumper; then back to mid-vehicle. And only then; going up from to the engine of WayneK’s full Long-Passages system.
That will be impossible to do in a trunk mounted.
A one end of vehicle; bumper mounted.
Tones; WK’s; Ron Lemlers tractors side to side straddle mounted systems are all Long-Pass systems.
Joni’s vehicle system installed; is a Long-Pass too.
Additive factors can add up favorably overcoming individual imperfections.
“Team work; makes the Dream work.”
Far, far different then the make-it-all-fit onto a shipping pallet footprint of mine and others beginnings.
S.U.
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The one thing that made a big difference on my WK Gasifier was on the hopper cooling tubes was adding fins to the tubes. This condensed more water out of the hopper. So I think adding more tubes would be better. Wayne has done this on his builds. I get very little water in my back condensation tank after the cooling racks. It is more of a soot collection tank. But I do drain water out of my hay filter tank after a good run on wood. I drain lots of water out of the hopper water / tar condensation tank. My next build will have a bigger tank and closer to the bottom of the gasifier for a little more heat. Mine tank is to far from the heat in the cold winter months for the northern cold states. Building your gasifier for your climate you live in is a other factor we need to figure in when building.
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Tone, this last drawing of yours is pretty much spot on my thinking for a correction to my gasifier.
Even now - without the lower nozzles - the Volvo idles very well, with the gasifier producing maybe only 1hp of woodgas. Also, it delivers good gas asking 50 hp of woodgas.
BUT - suddely asking 50hp, after idling for a while, is the problem. It can take as much as 20-30 seconds of hard pulling until the gas is good enough for full power.
This is what I THINK is happening.
At idle, all the oxygen entering the nozzles is consumed in the nozzle area (one of your earlier drawings). Charcoal further down is pretty much dead - starved of oxygen and relativly speaking dead cold. It’s of no use at this point. All the needed reactions take place in the nozzle area.
When I suddenly go WOT, a huge amount of air is rushing out the nozzles and penetrates the fuel stock. The charbed below is suddenly overwelmed with CO2 and steam, but it lacks heat to convert all of it to CO and H2. Not until the entire char pile below managed to consume enough oxygen to start glowing white hot (another of your earlier drawings), it’s ready to handle the new, higher rate of CO2 and steam passing by.
I believe the reason a real WK manages to handle accelleration well, is the size of the nozzles. At idle lazy air pours down the wall of the firetube - keeping the heat up in the charcoal further down - rather than penetrating at nozzle level.
In my case adding a few extra nozzles further down is an easier fix, so that’s probably what’s going to happen.
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