Hi Tom i used the blanket in the bottom of my home heating gasifier type wood stove, and even with no fire brick in front of it, when the bottom chamber is glowing red hot, 2" behind my blanket the paint is still sninny black. Though i think the blanket lost some of its density around ware the flame shoots out in my bottom burn chanber, i should add some fore brick on the sides. the dust and a 1/4" plate keeps bottom ok from the intence heat on my heating stove.
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Years ago I was playing with a oil fueled hot water heater/boiler. It was fun to see the white ceramic blocks turn red hot. To my amazement the blocks were soft material very similar to ceramic blankets. The fibers would quickly turn red hot to help combustion and the material was in much better shape than the rest of the tired stove.
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OK Tom, here is my experience with a ceramic fire tube.
I started with an 14 " diameter air tank 1/8" thick steel and added a 2" thick ceramic blanket so the interior tube ended up at about 10" for my 2.2 L engine and 8 1/2" nozzles. I did not coat the blanket with anything and do not have any problems with deterioration. The bottom of the fire tube above the restriction is also protected by the ash cone and the top area with the intense nozzle heat seems to put a black crust on the wool that helps protect it.
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Thank you Don; I was waitng for a report from you. I hope to get time to review the postings you put up along with the others that built with wool. TomC
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Wow! My wife put on such a feed for her family; I ate too much and couldn’t sleep so I had visions of wood gasifiers running around in my head.
My little experiment with just a fire tube and a restriction failed because of erosion at the nozzles. I know Mr. Wayne had that probllem as did others and corrected it with “heat sinks” under the nozzles. Can’t remember which trucks Mr. Wayne put the heat sinks in but I’m thinking Bob M. was one of the first, and I’m sure his daily driver got them. Are they holding up?? Are they working as “heat sinks” or are the sacraficial metal so the fire tube itself doesn’t erode?
Another thing that stirred my mind is for JO. I haven’t heard him say he has had any problem with his “grateless” experiment and more so, what about his ash pit “with no ash pit door”. If there is no ash pit door all the ash has to get caught in the cyclone?? As I remember the cyclone was only an old coffee pot and I don’t think it held much ash. How oftern are you emptying it? Any problems, and would you do that again?? TomC
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Good morning Mr. Tom .
Real glad to hear you had a great Thanksgiving , so did I 
On my 95 dakota I have heat sinks and nozzles that are tacked into place and can be pried lose if needed replacing .
The gasifier has near 20K miles on it now and the best I can tell from looking in the top they are holding up well.
On my v-10 work truck I have about 50K miles ( rough miles ) . Four years back I found a flaw in the burn tube and redid it. I put removable heat sinks and nozzles . Two and a half years ago I pulled them out and beefed them up some and put them back in . As of now the best I can tell from looking in the top all is well.
Keep in mind I use big nozzles and as many of them as practical . I want lazy air at the nozzle area to be sped up near the restriction where an ash cone has formed .
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You write that you have large and many nozzles, do you get the heat so you don’t have the tar anyway?Do you have a small restriction?
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[quote=“Jan, post:1249, topic:1225”]
You write that you have large and many nozzles, do you get the heat so you don’t have the tar anyway
Hello Jan
Plenty of heat but in the right places . Half million miles no tar .
Mid sized truck ( dodge dakota ) designed to run 60-70 mph has 7 1/2 inch restriction .
8000 pound full size pickup truck 50-60 mph 9 inch restriction .
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Thanks, then I have something to count on, and compare with my writings.
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Thank you Mr. Wayne for the come back. I was excited about how my truck ran with my 'sort of " WK gasifier, but In just 1-200 miles I was seeing spider cracks around the nozzles. I knew about the plates that some put around the nozzles and I didn’t want to do that because I am only running about a 9" fire tube and plated would make it smaller. Last night I remembered that you used 3/4 x 3/4 railroad spikes. Those wouldn’t have much affect on the tube diameter. Maybe if I can get out in that cold shop, I’ll pull the Imbert guts out and weld in some heat sinks and go back to the sort of WK design. Thanks again Mr. Wayne. Oh, I forgot. I am running 10 - 5/8ths diam nozzles— that is about the size of my second finger which is what you showed me the first time I asked you what diameter nozzles you use.
. TomC
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Hello Tom,
You’re right. All excess char and ash flow into the cyclone.
ALMOST two years of ALMOST every day driving with ALMOST no problems.
Advantages: Less maintence and no plugging. A tight charbed will clear up fast.
Disadvantages: Pulling too hard will sometimes make more char slip into the cyclone than I like.
Also, the gasifier has to be vacuumed from the top, twice a year or so. Heavy ash/slag (like sand) accumulates on the gasifier bottom.
The coffee pot was the collecting can on the Rabbit cyclone. The Mazda cyclone’s collector holds a little over a gallon. It’s good for 50-100 miles or so, depending on driving conditions. On longer trips most of the char is consumed and mostly soot/ash is collected. Short commute slips more char.
If I’d do it again? Maybe with a small bottom auger port on the gasifier housing, to be able to auger out the bottom slag. Also, I’d probably then make the lower housing a little wider to slow things down a bit.
BUT, my next gasifier will probably be more of a WK, with a low restriction and the char reserve inside the firetube. That’s where the heat is present.
With the Mazda gasifier’s char reserve exposed to the outer wall of the housing, it cools down quickly. With a sudden increase in power demand, it takes a while to heat the char and make it useful. I feel a lot more hesitation symptomes, compared to the Rabbit gasifier where the entire reduction zone is inside a double walled, ash insulated compartment.
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Hi Tom glad the Thanksgiving food gave you good visions of wood gasifiers running around in your head. Thats a good sign you will have you truck running on wood again.
My heat sinks are like Wayne’s Dodge Ram V-10. I also removed my heat sinks and beef them up on the edges so they could not warp. They have been holding up fine. My grate temperature runs as high as 1650 * f in the summer months. Cruising at 65 to 70 mph. and pushing it hard climbing hills. I am running 7 1/2 " at the restriction plate. I think the big heavy heat sinks also help in the turn down ratio in the fire tube.
Bob
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Good evening Wayne
Have a look at what my papers recommended for your figures.
Found out that Dakotan would be just over 5/8 inch and 7 nozzles.
Full size would be just over 45/64 inch and 7 nozzles.
Are these values close to the values you use, or are they far away?
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Hello Jan and good morning to you sir .
I think you may have an imbert type gasifier in mind . The gasifiers I build are a different animal . If I am building a gasifier for this truck the air holes or nozzles will be torch cut and be 5/8 - 3/4 inch diameter and 10 of them .
The restriction diameter and depth is adjustable to fit the driving habits, fuel size ect.
Are you aware the the air entering the nozzles are already near 1000 F ?
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Ok, you have a little lower speed on the air than imbert, much like a 2 stroke engine?
It is very good that you can raise the temperature to 1000f on incoming air, I think no one with imbert comes up to.
One small question, how does the amount of air work, when incoming air is so hot?
You can adjust the depth? the depth from the nozzles?
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Hi Jan, The hottest inlet temp I have recorded for my
imbert is 450 F out of the cyclone. It’s shown on my
you tube channel walk around firing.
Yes, the hotter the better! Pepe
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Hell Jan .
I don’t want to hijack Mr. Tom thread so I will be very brief.
The heat from the motor exhaust is sent to the gasifier incoming air as is the heat leaving the gasifier. Also the heat escaping through the walls of the burn tube is routed into the nozzle openings
This adjustment can’t be done on the fly but about a 15 min job with a cold gasifier . Can go from a small restriction to a larger on real quick . More time consuming to go from large to little .
For the gasifier to operate one needs time , temperature and turbulence . My gasifier gases has a lot of time and temperature but a lesser amount turbulence . To create turbulence one needs more vacuum from the motor . When the motor has to pull harder the cylinders fill with gas and oxygen less .
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Mr. Wayne, I will jump in with a question so you don’t feel you are intruding on my thread.
Jan; ‘‘when the incoming air is so hot’’? Interesting question. I think we all can invasion my 350 cuin. Chevy (can’t help myself-- I’m not a Dodge man ) at 2,000 rpm pumping air from outside through little nozzles at some 30 mps. Then the air speeds into a room where it meets with hot wood, and oxidize the wood. This adds ‘‘heat’’ expanding the air and adds more gases to the air. This air gas mix goes through another accelerating restriction, causing this air/gas to smash into red hot partially burnt wood (now being charcoal) , adding more temperature to the gas and chemically changing some of the structure of the air/gas(mostly now gases including much nitrogen). By now the air/gas is up to some 1200 deg.F.
Finally to the question. My 350 engine at 2000rpm pulls in X cu. Ft. of air at atmospheric temperature. By Boils Law, how many cu.Ft. is that at 1000 deg.f? Or is the air all a chain reaction thing where it enters at atmos. temp. goes through heat/chemical change and enters the engine back at atmos. temp.?
Hmmm! Maybe after all that blabber, I answered the question myself. TomC
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Jan, I think this has been discussed eatlier quite a bit.
I remember meassuring my preheat on the Rabbit gasifier. With a probe into the nozzle compartment through the light port I saw 300C+. I think we all agreed air had about three times its volume at that temp. This is one of the reasons I don’t quite follow Imbert charts.
On the other hand, with dry wood and lots of preheat, less air is consumed. This means less nitrogene - rich woodgas.
Why stepping on the pedal doesn’t increase power as you might expect. Going down the road I see myself often let the pedal up a bit - pulling less on the gasifier - but power stays pretty much the same.
When I experimented with vacuum guages on both sides of my oversized hayfilter, I discovered I only loose 1/6 of my vacuum. Anything that makes your system breathe easily helps.
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Yes, but you still suck in cold air and heat it on the way into the generator, will the airflow be greater?
So equal amount of cold air, but higher speed?
Excuse me, Tom.
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