Sean and Don,
In an ideal world I would water jet the TIG cup in half down the centerline and then hose clamp it to the end of the pipe. That would eliminate all the expansion stress issues.
You could also cut the cup with a diamond scroll saw blade:
Stephen
Sean and Don,
One last throught…Is your nozzle pointed at the exit pipe? That would likely help stretch the flame out in front of the tip and get the heat away from the metal parts. Otherwise, the gas will start to turn immediately at the end of the nozzle tip and retain more heat closer to the metal. This helped a lot in the Victorias.
Stephen
Don,
I can get it to flare after 3 to 5 mins once you get the generator going you can turn the vac off and the engine will pull the gas in Dan
So here are our results. Our square gasifier worked beautifully - thanks to Dan Hartman for an excellent workshop. It appears that our 30 gallon reserve will run the 27 hp Power Cube for 4 hours. Based on this success, we look forward to bulldozers running on char soon. Redirecting... See the bulldozer workshop coming up - http://opensourceecology.org/bulldozer-workshop/
Congratulations on a job well done. Marcin. I just went back to the first post on this thread and realized this is really your thread and I have been hi-jacking it big time. Sorry. 
Congrats Marcin looks good.
Alright, another convert to the dark side of wood (charcoal) 
Glad the workshop went well with good success. Keep it up!
Gary in PA
stephen,
The expansion slot might work if you use the spring action hose clamps. but you have to get it tightened back up to prevent air from coming out…
Ceramic stresses with heating and cooling cycles too so breakage is part of the game. I was just thinking shutting off the inlet, when it broke could save the iron from burning up, and give you kind of a notification that it happened so you didn’t have to guess.
So just a couple of tiny holes drilled in and a wire going through might hold it enough to keep tension on the return spring of a butterfly. (I was originally thinking just loop it over the end of the cup with grooves but you probably need tungsten wire to handle the heat.) In fact, it could almost be mated against a flat surface or one with a ridge in it with the guard over the top of it to help prevent the down pressure on it., then maybe some rtv stuff to try and seal it, but mostly to help it stick.
I enjoyed the workshop Marcin (but not the heat!) but I am wondering about the long term endurance of the metal box being only 8" thick.
When ever will it be obvious, that the combination of oxygen and white-glowing charcoal in direct contakt with metal is only giving destruction of whatever “superalloys”???
During past years, I have tried to make the point that keeping the metal nozzle on a “safe distance” away from the white-glowing char can prelong its working life far longer than these repeted directly in the char blowings!
A metal nozzle can withstand the hot return circulating gas alone, but NOT the direct physical contact with white-glowing char! It has manifold energy radiation compared to the return gas.
So, it is obvious that the only working orientation for the nozzle is direct or almost direct downward near the bottom of a cavity formed by a funnel or “roof” abowe it.
The back-streaming gases into this cavity are certainly trying to “avalanche” the slopes of the cavity, so the nozzle-tip should be kept higher than the normal 60 degree slopes into a cavity would suggest.
The cavity under the “roof” or funnel (umbrella) is an excellent place for taking out the gas, but the size (diameter) of it has to be sufficient to avoid char to be succed out aswell!
Somebody, who wants the nozzle duration prelonged?
Max
Max, I don’t like that you and I have misunderstandings, so let me see if I can “show” you, what I think you are describing. With a charcoal gasifier isn’t it best to remove the gas out of the top? I think you mention pulling the gas out of the cavity under the umbrella.
TomC
Hi, Tom!
Open Office drawings are not for free-hand drawing, I think.
Still, here is a sketch expressing the umbrella as a 60 degree cone.
The contour of the char under the bell is hard to render; the char slope under the bell and the blasting shaft excavation made by the air-blast.
The blast nozzle has to be trimmed from above, so the white-glowing charcoal does not touch it.
The gas can be taken out up from the bell through the outer tube as hot, or cooler through an extra opening in the lid.
The bell periphery has to be big enough, so the return gases are behaiving “gracefully” — not wildly!
Otherwise, the bell will be filled-up, and the nozzle gets no protection!
This is independent of which way the gases are finally taken out!
Max
Max, the diagram you shared with us would work well in my mind just for the nozzle requirements, (keeping the nozzle from the white hot char, and from being buried by the oncoming charcoal), but by taking the gas out from the top of the tank, seems to me that it allows the gas to cool off on the way through the charcoal to the top of the tank. however, how does one light the nozzle?
Hi, Robin!
Yes, it is a matter of choise; do you want steady output criteria (high), or do
you want varying criteria?
With the steady high temp output you can perhaps find a secondary use for the otherwise lost energy…
Heh… I would light the char! One way is to pull up the nozzle and drop down something burning; prelit char bits, a woodgas match, a diesel glow plug on extension, a suitable liquid burning with not too much noise…
All these under a slow sucking by a ventilator.
Another way is to have a special ignition tube in from the side of the vessel, ending near the region the air nozzle ”rules”. Use it the same way as you ignite a woodgas generator!
Max
Thanks for the ideas, Max, the last one makes good sense.
Robin!
Keep outside the cylindrical projection taken downward from the bell-perifery! Otherwise you disturb the bornating pitch!
Go down ~4" from the bell perimeter.
Hopefully, the bell diameter is no less than 3"!
Put a tight, greased, threaded cap on the lightning tube outside end, preferably tilting inwards – downward.
Max
Sounds like a good way to do it. Thanks!
Hi Max, I’ve been looking and thinking about the umbrella - nozzle arrangement and cannot see how it can possibly work as explained. The oxygen comming out of the nozzle will impact the charcoal located some distance from it causing the charcoal to oxidize. This of course makes a tremendous amount of heat and carbon dioxide. The nozzle is some distance from this heat which will protect it and this makes sense. The problem I see is if you take the gasses from this oxidation zone directly up an outer tube that is concentric with your air inlet, you will only get carbon dioxide.
I see this type of set up working IF the hot carbon dioxide is first run through a bed of charcoal to reduce it into carbon monoxide. This will happen if the hot gasses are draw off to the side or out the top of the charcoal reactor but not concentric with the air nozzle pipe. I might be missing something here so will look forward to your reply.
Gary in PA
From the very beginning, there are two output routes on the repertoire allowing easy sampling for comparison analysis.
The coaxial arrangement gives easy access to inspect the blasting nozzle tip, trim the height just above the char surface, aswell as for lightning exercises.
The outer coax tube is kept closed, if using the lid exit and visa versa.
The sketch represents a blasting injector nozzle tip — NOT a floppy “easy going” air inlet.
An easy floppy air stream will certainly give a local recirculation stream on the charcoal surface, with the supposition of creating mainly CO2 …
However, a blasting, high velocity air stream burns its way down into a “pitch” with high turbulence.
You can assist this from the start by poking a narrow and deep starting hole under the nozzle tip…
Using the bell as exit or not, does not prevent the reduced return gases from the routing up through the surrounding char, back to the bell and being succed with the air blast once again into the pitch…
Max
Ok, I did not know the sketch represented a nozzle blasting air into the charcoal bed. I was looking on it as you mention “easy going”. Blasting air into the char will force the carbon dioxide away from the oxidation area and into the surrounding charcoal where it will then be reduce to carbon monoxide. The key I missed was the high velocity of the incomming air.
Thanks for the clarification.
Gary in PA
