High, Jan!
28.12.2020
Almost! It seems that the decreasing in “inner” diameter decrease
with each step downward is still missing.
It should be a screw decreasing in diameter downwards as it turns around one circle-turn.
So starting from the “plane” bottom upwards, it should start with a smallish inner diameter, a little bigger than the restriction diameter.
Then taking 3 steps up with successively increasing height and inner diameter.
This very irregular “staircase” is for dislodging any possibility to establish any symmetrical vault, thus promoting flow.
Hopefully… cold try with wooden carwed bits… If the wooden “formationing” allowes cold fuel distribution, then burn it up and do it from metal and try again…
But, take into account, that cold, hard wood flows much more unwillingly than soft-surfaced char!
Max
Hi Jan, I have studied your build some and looked at the pictures of your wood in the hopper. At what temperature are you running going down the road in your hopper? Just looking at the wood left over in the hopper tells me you might be running your hopper to cold of a temperature.
Have you tried wrapping your gasifer in insulation blanket yet?
How longer can you hold your hand on the lower part of your gasifer and the lower part of your hopper after driving it. If you can’t hold your hand on it for like 5 seconds then you are losing valuable heat that needs to be inside the gasifer and not going to the atmosphere.
Just wrapping the area where your hopper is connected to the fire tube will help. I think your wood should be cook down, torified more.
This simple test could save you a lot of time rebuilding your unit.
Have you also tried different sizes of wood in length and diameter. It looks like you are using a Rebok cutting machine. Different sizes a shapes do not bridge as easily.
Your cone you made should have planty of heat under it so it can help cook the wood down and torified the wood.
More heat in the hopper. I am running my hopper at around 135 to 150 *f or 57 *c to 65.6 *c. This is with a full hopper of wood. My temperature probe is 12 in. Or 30 cm above my nozzles. When I reach 200 *f or 93 *c I am out of wood in the top part of the fire tube. The wood remaining in the hopper like yours is torified black almost to charcoal but not quit. I figured the top of the fire tube runs at the lowest 350 *f or 176.7 *c.
In the bottom of my hopper there is no sticky tar it is black chared.
So I say get more heat into that area first then go from there. Resizing wood. Ect…
Bob
Thanks for your answer Bob, I think you are right that wood is the biggest cause, when I drove on sawn wood the problem was less, needed to shake the car when the temperature rose.
The temperature is usually at 55-75 degrees C (131-137F).
When it rises above 95 degrees c (203f) I run out of wood or a hang.
I have the probe about 35cm above the nozzles, but I have a very small container, enough for about 25-30km.
I have started to insulate the gasifier, but need a little more sheet metal to cover the surface all the way up to the hopper.
I have also made angled nozzles as Kristijan and Joni suggested, tried today with the same wood that went wrong last time, but see no improvement yet.
At the bottom of the cone, the tar is charred even on my hopper.
I have sawed up the wood that I had on the platform last, and with it it works much better, I have a similar wood machine as you (I think) see page 331, but am starting to think that the knife is not sharp enough or that the wood was too old , had begun to rot, so it chipped.
Jan; I like the insulation you put around the reaction area. Hope you get more material and can put another layer of insulation over what you have. If you don’t insulate the hopper, at least get the second layer in the reduction area to extend up and cover the tapering part of the hopper. Keeping that area hot and dry will prevent wood from sticking in that area. TomC
Hi Jan, about your wood. It looks really clean cut wood. The wood I have is not. The way my chunker works it cuts the wood but it also fractures the wood. I have used wood that is been in the cherry wood branch pile for 10 years, very hard and dry. This cherry wood is a hard wood to begin with. I have chunked up poles they use for propping up the limbs in the orchards with fruit on them. It looked like your wood 1" to 2" or 2.5 cm to 5 cm. In diameter and 4" to 5" or 10.0 cm to 12.5 cm long.
When I used it I had bridging problems. I mixed in bigger and smaller pieces of cherry wood the bridging was solved.
Now I know your fire tube is small than mine. But my fuel is still in many different sizes and shapes, also it is fractured. For me this seems to work the best in my gasifer. Just keep working with your wood sizes.
Bob
This morning the throttle was so tight that I had to have a screwdriver and break it loose.
Now I have tried with the cone as JO, no slope at all at the bottom, seems to give more water in the container, good.
Insulated gasifier, and upwardly directed nozzles, have worse problems with hanging than usual. Hmm
Jan, I don’t know what to say. Since I’ve had very little problems with bridging, even with the tiny 8" gasifier, I don’t know what to suggest next.
Except, maybe if you go all the way and make an inner hopper wall. That would keep the entire wood pile warmer and the sweaty chunks slipprier.
Yes, you will sacrifice some hopper space, but…
Stuck throttle plate:
Yes, collapsed bridging is the most likely cause for making tary fumes, but not necessarely from your previous burn. This was a pretty cold morning. Could be frozen condensation, but it’s possible tary fumes, made a long time ago, still interfere with your throttle plate axle. The only thing I found, that can get rid of it, is either acetone or burn it with the torch.
I have my car in a heated garage so it does not freeze.
Do you have a picture of the one you had in Caddyn?
Yes it is strange, but I have had problems with the wood all the time, I have tried to get a little bigger pieces of wood as well, but it does not seem to help.
There is no tar on the wood container, but it starts on the cone.
Removed the bends on the nozzles today and then it went much colder in the wood container, but that is natural.
I had no problem with the wood today either, but did not go more than about 15km + 15km home, had the same wood that was in the container yesterday.
May probably start thinking about creating a new one.
I found it finally. This when I lifted it out to clean out debrie from the hopper gutter.
It’s made similar to my current setup - just a sheet from a barrel.
JO; What is that picture? It looks like a liner for your hopper. If that is correct, are thete holes in it, to let the gas go through to contact the cooler hopper wall and condense the vapor out? TomC
Jan, , On bridging-- the only time I had problems was with short trips. On my trip tp Argos, 300 miles and don’t recall how many stops for reloading, no problems.
Sticking throttle-- Yup! Did the ‘‘butter fly’’ stick or something else? Mine, the shaft was stuck in the throttle body. Had to tap the arm attached to the linkage (used hammer) until butter fly was open and then tap back closed. Repeat until free to move with hand. Some lube or acetone added helps. My problem started when I tried to clean the build up of soot with carberator cleaner. Don’t think my problem was tar. Did your butter fly ‘‘brake’’ loose or did you have to force it all the way open and then back close.? My guess, if it brakes loose it’s tar. TomC
I tried to clean the intake yesterday, it’s tar really sticky, have not had so much before.
When I look at JOs, I see no major difference, so I have to do or have something completely wrong. @TomC How high a hose do I need for a vacuum meter, 30 cm (11.5 ") is this enough?
Jan, You see no difference beyween you and JO. Are you talking about gasifier design or carbon build up on carberater? Manometer— if you are going to put the meter in the cab, I recommend using the one that requires a jar of water. I plug one end into what you want to read-- cooling rail, ash pit, hopper, filter. I ran the other end through the light mounted on the cab above the back window. That brought it in under the head liner. Ran under the liner to the front windshield. Then drop straight down to the jar sitting on the floor. Fasten a board about 2-3 inches by 30 inches to the dash behind of the plastic hose. Mark the board with inches or centameters as shown in my pictures. ----- If you want a portable manometer make it like the pther one I showed. Get a 3x36 inch board. Fasten one end of a clear plastic tube to the top face of the board. the run tube down to the bottom. Make a bend and go back up the face to the top. At the top fasten it, but then leave at least a yard/meter of tube hanging loose. This allows you to hold the board in one hand, and stick the loose end into a small hole for the reading. I have holes all over my system to use for checking vacuum at different points. I put plugs/ screws in the holes when running the system. Either should allow a 30 inch water vacuum reading.
JO, Great explanation of your hopper liner. I never thought of a cooler/condencer like that Your ‘‘signature’’ confused me a little. Two people on here have big wood piles—WK and you. I sure wish I could talk Max Gasman into using simple drawings.
