Hi, Tom!
Is your current hearth still looking like this 03/15/ 2009 one?
Do you have a reacent drawing of the current one?
A drawing with measures makes commenting more meaningful…hopefully.
Max
what is the fast’est you can drive your truck with out running out of power.seems a bit low on reserve char.I am not knocking it though, its a fine work in progres like all gasifiers they have good qualitys in some ways , and not as good in other ways.
Max; Don’t have a drawing with dimensions so I will list the dimensions along with a drawing;
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Nozzles; number—5; nozzle diameters ---- .375 inches; nozzle tip circle— 9 in. location — 4.75 in. above the restriction
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Restriction; diameter — 4.25 in.
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Grate; location — 4.50 in. below restriction, construction — an 8 in. circle made of 3/8 in. rebar, with parallel bars attached to the bottom, spaced 3/8 in. apart.
2 Likes
Tom, Looks good to me buddy !! Your 5 nozzles will prevent you from going back into combustion mode but you may get starved on the hills and it is hilly in your area. I am running 8, 5/16" nozzles now with a 3.5 inch restriction but my 4.3 liter truck like yours pulling the gasifier trailer does around 65 on the flat in Illinois. My 2.2 liter truck does much better with the same trailer. I have been over 80 with it a few times on the flat but it revs over 4 grand on the gasifier and with just a 2 inch feed pipe instead of 3 inch. I have been hauling my new gasifer around for a week or better to see what is going to break before actually driving with it. The cyclone fell off a couple of days ago so I had to add some straps etc etc etc … It seems to be solid now … Next will be to see how all the tape holds up when I finally fire it on the road and then I will have to switch to steel. It is a big difference between testing a unit that is stationary and then running one down the road with flowing air to cool things off. It was 20 here this morning … Heater croaked in my office … I wouldn’t have gone to my office but I had to repair the controller for my solar and wind stuff. I imagine similar temp at your place but maybe a bit higher with lake effect … M
Hi Tom
One of my first Gasifier builds was similar in design to yours, but until I had joined DOW I did not realize the importance of the volume of your char bed, and the critical nature of pree heating the incoming air.
As to the blockages , pine seams to have a lot more resin in it than other species, so possibly glued things up.
Try add some charcoal to your wood fuel , to help dry and also reduce the time of converting wood to char.
Essentially making it a charcoal gasifier.
Hope this helps
Patrick
Tom Collins’s picture
Gasifier Dimensions
Hi, Tom!
There seems to be nothing wrong with the internal dimensions, but the general building style, does not take good care of the generated heat; you are burning extra wood just to keep the process going.
Your “cold” upper hearth seems to force you to use a narrowish restriction.
Building a heart inside retained ash, all the way down to the grate and preheating primary air makes a difference.
Having the whole process inside ash, but not flowing gas trough ash is saving heat, without disturbing the process.
Max
Thanks for taking interest in my problem. I totally agree with what you said about the char bed and pre-heating. I have thought about starting over again with a DOW design, but my time in the shop is very limited at my age / physical condition / and the climate up here in Wisconsin. Trying to see how I can increase the char depth with just modiste modification.
The pine I am using was “studs” out of a 75 year old barn that I’m tarring down — very dry.
I have some but very little air pre-heat around the fire tube. I do have a heat exchanger to add heat from the gas to the air coming into the gasifier. It is a “counter flow” heat exchanger. ( got the idea from the “naked mechanic” in Australia { he has since passed }) It is a 3" hot gas pipe inside a 4" air pipe with the gas going one direction and the air the other. Pictured below. I have since built a box around the heat exchanger to protect the air pipe from direct contact with the “wind” and I stuffed “some” insulation around the pipe ( not enough because I didn’t make the box large enough)
http://jamclasses.drbanjo.com/static/dimages/100_2193.JPG
Hi Tom, I ran a hopper full of chunks through my new machine stationary today at full pull to see what would burn up and what would hold … Made a few RTV repairs but it is ready to get hooked to the truck. Nice clean invisible gas flare out 4or 5 feet. I did the napkin test at 3 feet in the ripples … I had to re-braze my poker holder as one of them broke loose from about 50 miles of shakedown cruising … brrrrrrrrrrrrrrrrrrrrrrrrrrrr Mike
Hi Tom
How much space from the grate to the bottom of the barrel ?
Can you extend the fire tube barrel and then extend the fire tube its self ?
What diameter is the fire tube ?
I see that your hopper is a full barrel, you could sacrifice some of that hight.
Just ideas
Thanks Patrick
Max; I need a little more explanation about your comment.
Building a heart inside retained ash, all the way down to the grate and preheating primary air makes a difference.
Having the whole process inside ash, but not flowing gas trough ash is
Are you saying take out my “tar dam” and let the ash fill that space? I thought of adding a cone from the restriction to the grate, but that would be flowing the gas through the ash. When I clean out the ash pit, I see all that marble sized charcoal which I think is smaller than what other get, but I want to try for just ash.
Patric; It kind of sounds like you are saying build a WK gasifier to replace mine. Good idea, but not sure if I have the time. I keep looking at that “big” fire tube and thinking it is a lot of weight. I saw your post the other day on the one you are building for a 318 engine and it appeared to be made out of “thin” stainless flat stock and rolled into a tube after you put the nozzles and heat sinks on it. Did I see that correctly and you did state what type stainless but I didn’t see the thickness.
TomC
Hi Tom
I’m thinking of ways to modify what you already have to have a larger char caring capacity.
To try get some more heat could you weld a second baffle around you lower fire tube and divert the incoming air through there first then up to the nozzles ?
My fire tube is 316 stainless and 8mm thick- 5/16 in thick and ist for a 350 cdi chevy .
Thanks Patrick
Read it correctly it was 50 X 8 mm stock out of 316 stainless. Which for us metric handicapped means 2 X 5/16 or there abouts
Tomw
Edit
Sorry Patrick typing at the sametime as you
Ok. Patrick has got me thinking about doing a “sort of WK” gasifier— you probably have figured out by now that I can’t just copy something of someones… So, Mr. Wayne— I am running a 4.3L engine (I think that is about a 265cu in.) You have built a 12" dia. tube in 16 &18 in. and I’m not sure without looking back you may have built a 14" tube and I know you built a 10"dia tube. All these changes were because of different size engines. I am thinking along the lines of using a 12" tube that I have only shortening the height. Make it in the range of 10" tall. ( on the Chev, on the drivers side the undercarriage is full of gas tank, and on the passenger side sits the muffler, so I don’t think I can gain enough by cutting a large hole in the bed to sit the gasifier in.) Considering the smaller displacement— what do you think about a 12" dia by say 10 (?) tube. I know your 10" dia was for about the same displacement as mine, but I think you stuck with 16" height.TomC
When I look at my build right now, with the “tar shield” covering the nozzles, it resembles a WK fire tube of about 9" dia. by 4 1/4" from nozzle to “choke”. I don’t understand the theory between Embert and WK other than you are BIG on preheat, less on nozzle velocity, and larger char bed. For the larger char bed I would say a 12 x 10 tube would give about the same char bed as a 10 x 16 tube ( for the same restriction.) Which way would you go??TomC
What is the diameter of your outside barrel on the bottom Tom?
Good morning Mr. Tom
Here is the link where I tried to answer Don’s question , kinda similar to yours .
http://driveonwood.com/comment/32328#comment-32328
My tractor is a 152 cid and is operated at slow rpms ( 1000 -1500 ) usually.
If I were designing a gasifier for a V-6 truck I would use about the same gasifier for a V-8 if the trucks were about the same size , weight and profile . When driving the V-8 we may be driving at a slower rpm and will be using less throttle . Driving the V-6 one may be driving in a lower gear or at more throttle .
In short the smaller motor is having to work harder to do the same work as the bigger motor and the demands of the gasifier will be similar .
Ok friends.; Here is where I am at.---- I have a truck that I can drive. It obviously needs improvements to be competitive with the level of the WK design.
I can keep my truck as is and try building a WK design this winter.
I can keep my truck and build a new “business” part for my LaRosifier. If I modify the LaR, I have gleaned from Max’s comments that I should take out the “tar fence” and rely on the ash filling that area, of course the shape of a cone going from the nozzles to the restrictions. Thus gaining insulation in that area. Then I gather having char build up on the grate should allow the gas to go past the char with out going through it. (Max; is that what you had in mind??)
Then I got from Steve U ;; Insulate around the brake drums with alumina ceramic insulation. Good and easy fix. Then go with 10 or 11 smaller nozzles both in nozzle diameter and length of the protrusion of the nozzles. That will change the nozzle diameter if I just shorten what I have and I wonder if that’s wise as it is a dimension from the Embert design. Then encapsulate the air feed tube and gas exit tube. I kind of think I am doing that already in my counterflow heat exchanger. It is doable, but would require a new heat exchanger of the WK type.
Oh, and if I’m going to double the number of nozzles— should I move them up to near the bead area of the rim flange to get more distance from the nozzle to the restriction?
I know you are asking, “why don’t you just build a WK???” I can’t answer that only, I have spent almost 14 years on this project and just copy a design, even though I know it is proven and works. I really envy Don Manne’s build with the small vehicle and smaller gasifier. That was a copy (sort of) but yet he has an large amount of his own design.
Max and Steve I hope to hear back as to my interpretation of your suggestions. TomC
I have an understanding where you’re at Tom. There are so many creative minds on this site and everyone want the other to succeed no matter what is built. I tossed around a few ideas myself, I opted for the WK modified to a couple of other ideas. There are a lot of WK logged miles, not just by Wayne but about 50 other people?
My suggestion is take 1-3 hours out of your day Friday and log into the ‘Hangout’. There you will receive a lot of input and insight to weigh things out.
No matter what route you take, the end result is- you’ll be driving on wood.
I know how you feel. I have been experimenting with wood gas since the late 70’s when mother earth news built their truck and power plant. I spent a lot of time, and some money with limited success. After seeing Wayne’s system I started building. I think using a proven system will save a lot of time, money, and aggravation. I am putting my own spin on some parts, but keeping with the basic design. I am just thankful I found this site, with all it’s members willing to help one another. Like they say don’t try to reinvent the wheel. Al
Hi Tom
Here are some dimensions recommended buy Vesa Mikkonen’s book.
For a 4.3 lt engine running on wood, his design is very similar to yours
Diameter at nozzles 280 mm or 11 and 1/4 in
Nozzel diameter 12 mm or ½ in, 10 nozzles
Distance from nozzles to choker plate 150 mm or 6 in
Choker plate to grate 180mm or 7 in
Diameter of choker plate 160 mm or 6 in
Hope this helps
Thanks patrick
Thank you Patrick; I have got to find some place to store this in my computer. I like to be kind of original in what I build but I do try to stick with proven dimensions — such as the Embert. These dimensions appear to give me more of what I was thinking I need. It is all changes that are possible and still using the Rotor/Rim method of construction. I could cut 1"+ off from each of the nozzles I have for an 11"+ nozzle did. Then maybe add a new nozzle in-between each existing nozzle for a total of 10 nozzles. The existing nozzles are made of 1/2" pipe. To get the proper distance from the nozzles to the restriction, maybe I could place the new nozzles at 6" and leave the original at 4 3/4 in.(each one would be staggered from the last one) With the shorter nozzles, I could do away with my tar fence, which is something Max suggested if I read him correctly. And then wrap the brake drums in a ceramic insulation as Steve U. suggested. This gives me a lot of ideas. I really do thank all who have taken the time to post here and help me.Keep the ideas coming. I’m a ways away from starting a rebuild. ( I am building a hutch for my daughter in law) TomC