Sorry Bill but it isn’t anything that I want to brag about. You have heard me say I’m taring down an old barn. She wanted a hutch made out of old barn boards, with a " chicken wire" door. I was suppose to just cut the wood out for her to put together, but I found the boards were only rough sawed so no two were the same width or thickness. I had to put it together to know how big to actually make the next part. Talk about “hard” I am at the point of inlaying the hinges and I can hardly chisel that old wood.TomC
I like the sounds of that hutch even more now Tom.
I was going to suggest to you about selling that old barn wood. People pay good money for that. I’ve done wood working as a hobby in the past. I don’t envy you trying to work with it. I’m sure it will turn out as she wants. My daughter’s are the same way. Lure me in and then I end up doing it. hahaha Them girls know how to work their Dads.
I am still interested in a picture if you don’t mind.
“Leatherman’s” cats! Not too long lived…
The reduction tube can leave a generous ½" (half inch) open ring at the top; the vibrating gas-stream will keep the outside well stuffed with ash, soot and small stuff.
If you cannot lay your hands on a commercial “L”-flange, then perhaps rolling something alaike from a round-cornered angle iron.
This way you have two easy welding seams to do and no “blacksmithing” hammering glowing tube or plate.
The angle iron may need heating to bend without ripping, but the hammering part is mostly avoided.
Another way to do it, would be to make the hole diameter in the bottom plate 1.5" narrower than the reduction tube diameter, then saw up narrow stripes in the radius’ direction 1.5" long.
This means, that half the toe (0.75") “stays” inside the reduction tube diameter, and the outer part of each toe (also 0.75") stays outside the tube diameter. Each toe is = 1.5" long.
The plate is still all flat!
Then, bend each “toe” up with a good curve (even round) upward and weld them a bit above the tube end (plate and tube standing on same plane = welding table). The well-curved “toes” would then provide good elasticity for the rounded, gastight joint.
Neat seams, not too “bully”, otherwise the elasticity is lost.
The grate:
This flat grate is not heat insulated as vertical ones are, by an outer cylinder, etc. We need to keep a “furious” blow to avoid ash-settling and also let small char slip through.
To not slow down the gas stream too much, the reduction tube diameter
would be 6"-- 6.25". The flat iron ring then 7" diameter.
A deacent blow-out, if half the area is covered by the angle bars, and the “other” half is slots between them.
Meaning, ½" angle irons, and ½" slots between them.
Worthwile to observe, the ends of the angle irons MAY NOT be blown clean from ash in the ENDS! That’s destruction!
A stop triangle or something has to retain and protect the ash.
I gather, that everybody knows that the anglebars cannot be WELDED TO the the flat iron ring in both ends… either end or both, has to float ON a support giving sideways stability and keeping the “ditch” upward.
(Easy: One end through a hole in the ring, each second from either side, the other end welded)
Another methode to assemble the anglebars:
Perhaps neater and easier to do, cut 90 degree angles into the upper edge of the flat iron ring. Deep as the anglebars, projected in the direction of the bars, especially nearer the sides of the iron ring.
Weld only in one end! Each second alternating weld end.
This will keep the anglebars flat with the reduction tube bottomplate.
This may work, if not too much gas is leaking between the grate-ring and the reduction tube bottom-ring plate.
To assist in this, the grate-ring can be surrounded by a rectangular flat plate “pointwelded”, so that it can be hang up between two parallel anglebars, like a table-drawer.
The grate-drawer can then be drawn to either side and reached from an inspection door or hatch.
One end of the rectangle plate can be left longer IF one wishes to avoid to empty the reduction tube, while drawing the “grate-drawer” to the other side for inspection!
When this is digested and discussed, we go to air preheating?
Max
Ok Max; This is getting to be a much bigger project than I had anticipated. But the following is a revised drawing of my LaRotor with what I think are the changes you have suggested. One of the major changes that I don’t know how I am going to deal with is “opening the old restriction” to over 5 1/4 inches. That is going to mean removing the bolts that are holding the two rotors together. Where did you come up with a 5 1/4 in restriction? It has been many years ago that I did all the calculations for the 4.3L but I thought I had done it correctly at the time… Another thing that is getting to be a problem is the distance under the grate for the ash collection. Hopefully, if I end up getting “ash” instead of “slip char” I won’t need as much room. If I have to I can cut the tank that everything sits in and add a couple of inches to it— but again that is getting into a lot more work.
I do have a gasifier that has worked for several hundred miles. The biggest problem was the last trip out. In my tare down I did find a rather large (baseball) size “brand” sitting in the restriction. I don’t know if that was in there during the last run or it got pushed through the char when I was cleaning out the wood/char/ash.
Anyway, please look over my sketch and see if I have interpreted your suggestions correctly. TomC
What is your definition of a “brand”? Do you mean partially charred wood? If it is baseball sized, is that the size of the wood you are using or did one extra large one get in there somehow? That seems quite big for an imbert.
I’ll let Max answer this but don’t you need spaces between the grate angles?
Good drawing!
Modified Rotor
Hi, Tom!
Some details are very well perceived, some less…
You have made it clear, that you need more power; more heating in the upper end, easier flow, smaller losses, more effective reduction = more gas.
The new measures aim at that.
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The nozzles are NOT “two-stage”, as earlier described.
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Your sketch is not clear about what is “collected” at the restriction opening; please, clarify.
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The restriction tube building seems to be correctly received, but modified; the tube has “jumped up from the table”.
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The grate flat iron ring, and the “drawer” concept is also well perceived!
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But the grate bars have not any resemblance to my description.
…
In my two different descriptions of the grate, neither one puts the grate bars UNDER the flat iron ring!
In the first one they are put through holes in the iron ring.
In the second they are countersunk into the upper edge.
Please, re-read the description!
Max
Hi, Don!
I am equally interested to hear answeres on your questions; reveals where to go next…
Max
Hello Don; Yes, by “brand” I mean a piece of wood that is “partially” charred. And yes, it was on the large size, but I’m sure I have run pieces that large before. I aspire for “between a cigaret pack and a box of matches size”. Something I think Max said long ago. But I am not working with 1" x ? or 2" x ?, I am working with round limbs. So it is just an estimate on cigaret/matches theory. When cutting cow patties they are thicker than one inch and form nice “chunky” blocks. When I use the “chunkier” I get a lot of variation because the wood is so dry, that it “shattering”. Thus there is a portion that is “chips”. Not good but that is my reality.
And “Yes” I incorrectly drew my grate. Should have had 1/2" spaces between the angle irons. Ya caught me. Tom C
Max I think my sketch is doing the job. I sketched what I “thought” you were saying into something we could both look at and see my misinterpretation.
The Nozzles; My drawing was out of scale so the picture is not quite correct. I am shooting at 1/2" long cylinders with 1/4" inside diameter and I will chamfer the end where the air comes into the cylinder with a square cut off exiting face. They will be held in by knurling the outside for a tight slip in fit.
Restriction; The present restriction will have to be opened up to about a 6" diameter so it has no effect on what ever size we use for a new restriction. I was planning on stacking rings up to form an inverted “tea cup”. That won’t be necessary. If I set a 1/4" plate with a restrictions hole ( 5 1/4" Dis. ) on top of the present restrictor plate, I should ge the required 4" between the restriction and the nozzle height.
Restriction Tube; “jumped up from the table”??? I gather that you mean to put the bottom edge of the restrictor tube “plate” even with the bottom rotor disk’s lower surface. I’m not sure how I can fasten the plate to the brake drum there. I had thought I would put bolts through the rotor and the plate to hold the plate up. I hesitate to “weld” it to the cast iron brake drum. Brazing may be possible but with heavy castings I have had trouble getting enough heat into the cast. I do have the upper rotor welded to the tire rim and this is something I will have to check very closely when I take it apart.
“Then, bend each “toe” up with a good curve (even round) upward and weld them a bit above the tube end”?? “Above” the tube end. That would mean “inside” the tube, or “outside” the tube. Shouldn’t the “toe” be but welded to the face of the tube circle?
Grate; Wow! I really blew it. Your explanation was quite lengthy with several possible ways to make the one grate you discussed. I must have been asleep during that “class”. Sorry and thank you for catching it. I will leave a 1/2" space between each angle bar. My thought right now is to use the method where you put notches in the top of the ring, fill in the ends of the angle bars and weld every other bar at the opposite end.
TomC
Writing, reading, writing…
Hi,Tom!
The nozzles:
Chamfering is good, a rotating round file can make it even more trumpet-like. Hope the knurling lasts…
Restriction:
CORRECTION 11.24.2014:
The restriction = 5 1/4" NOT 6 1/4" !!!
" , then a short (~1 ½") long 5 1/4" tube-bit…"
If a hole 6 1/4" starts to “affect” the 4 or 6 bolts, keeping the rotors
together, then a short (~1 1/2") long 6 1/4" tube-bit could be fit into the
6 1/4" hole. To avoid slipping through, it has to get 4, or more “weld-butts”
on it at ~mid-height. Still removable!
In worst case, new bolt-holes, etc…
…
Reduction tube:
The reduction tube bottom plate is thought to be bolted to the lower rotor from below. I never put forward any other alternatives!
As a separate welding instruction for the bottomplate and the reduction tube I said:
Put the bottomplate on a weldingtable and the reduction tube STANDING ON THE (same) TABLE. Meaning, in the hole between the upbent toes.
(The tube cannot stand on the table, if you leave the toes inside!)
In your sketch, you have lifted up the tube from the table!
That was not meant to happen!
“… and weld them a bit ABOVE the tube end.” !!!
As the tube STANDS on the flat welding table, the toe-welding can only be done on the outside!
Is there still something unclear?
…
Grate:
This you seem to have got right!
A little hint:
Draw the EXACT center-lines of the bars on the iron-ring upperside, aligned with the “oppsite side”.
Then cut with an angle cutter and a 0.040" cutting disk a vertical cut on each centerline, aiming at the corresponding point on the “opposite side”.
Make the cut a good 1/2" deep, it will help to keep the rest of the cutting “on the spot”!
Max
I worked all day on the reduction tube and corresponding plate. I misunderstood about putting the reduction tube “inside” the bent up hole in the plate. I will have to heat it up again tomorrow and open the hole enough for the reduction tube to slide through and down to the welding table. I had a good fire going in my wood stove today so I used it for a “forge”. The last bottle of acetylene cost me $100 just for the refill so I was happy to try using the old “forge” method of heating and bending the steel. My reduction tube and plate are made out of 3/16 " instead of 1/8 " so it was a lot harder to form that I had hoped.
After 6 or 8 hours of standing on the cold cement, my feet are frozen. I put some chemical pads in my shoes that are suppose to keep your toes warm. If they worked I don’t know. I might have been in the house after 4 hours without them.
I will post pictures of each part as I get them finished for your scrutiny.TomC
Here are pictures of the reduction tube and plate. I had to put it in the fire one more time to try to straighten some warpage of the plate. ( took pictures while it was looking shiny) TomC
http://jamclasses.drbanjo.com/static/dimages/100_2368.JPG
http://jamclasses.drbanjo.com/static/dimages/100_2367.JPG
http://jamclasses.drbanjo.com/static/dimages/100_2365.JPG
May i ask what was the condition of the fire tube after takeing your unit apart. is your fire tube in good shape behind all the rotors,and how thick is your fire tube itself.Allso what is the toltal hights of your burn and housing below the hopper. THANKS TOM C
tags /
Reduction Tube and Plate
Hi, Tom!
You seem to have made a big job! The photos do not disclose the flatness of the bottom plate, that is the doer’s headache…
What is the inner diameter of the tube? 6" ?
Welding beads between the tube and the curve of the bottomplate are worrying, as they may prevent smooth flexing! Would not welding on the outside have been enough?
A bit ranting, but now you have to check if the tube-bottom really touches the same plane as the bottomplate…
Then, lining up holes for bolting to the lowest flange. The more bolts, the less leakage.
Patience,
Max
Good evening Max;
Yes the flatness of the lower plate is a problem. After I took the pictures I through the whole thing back in the furnace until most of it was red hot. Then I put it between two rotor-brake drums and sat them on a jack which I pushed under the truck and jacked up against the frame. They sat for a day and cooled. Still some warpage.( less than 1/16 " ) But I think if I put more bolts around when I attach it to the lower rotor, I can pull it up. That is the plan anyway.
Yes I made the tube 6". Working on the grate and have that at about 7 1/2 inches in diameter.
I only welded the plate on the outside. When I slit the hole in the bottom plate and bent the tabs up to accommodate the reduction tube. the opening between the tabs was a triangle. When welding the widest open part I suppose I did burn through, but by that time I was almost up to where I welded the tabs to the tube. I don’t think it changed much as far as adding a stress point.
Got above freezing today but I still had to go through a lot of wood because everything in the shop had soaked up the cold of the last 10 days. TomC
Kevin; I don’t actually have a “burn tube” in my present design. It is just a “tar fence” and I rely on the build up of char between the nozzles and the restriction to insulate the “fence”. Can’t tell you how thick it is but I would say less than 1/8 ". The condition was very good-- no problems found. The distance from the nozzles to the restriction is 4 1/2 inches. The hopper sits on the flat ring above the nozzles a couple of inches.
http://jamclasses.drbanjo.com/static/dimages/100_0976_1.JPG
Because i am new too the study of wood gasifiers, i see a vast difference in the designs, yours must be sort of a true imbert, and waynes says his is a mix between imbert and feema, The compactness of yours seems nice.The main thing is tar free fuel as sure as posible. happy modifying looks good and better.THANKS
Hi Tom,
There was a mention of loss of char bed a ways back. Let me refer you back to the imbert dimensions diagram as a standard. The reference line is taken as 1" above the centerline of the nozzles. One of the first questions I posed to SU waaaayy back was, “is H plus R the distance to the grate”? Yes was the reply. Initially, before I understood its purpose, I thought that was a huge pile and questioned it. However, I built to it with success. My grate is 13 1/8" from the C/L of the nozzles. With the grate only a couple inches below the restriction your char bed is relatively small and with that a short residence time for gases passing through the char bed expecting to be reduced chemically to burnable gas. It could be that not all the gas is being reduced thus diluting your “good” gas with “air” and humidity (moisture plume). I think this is what Wayne was essentially saying back a bit. You don’t need a cone, you need a very wide grate with 2" sides at the proper (imbert) level and your char bed will form its own hill of char, getting much bigger and deeper. I think increasing the size of your char bed would heat things up for you.
NOTE: On my drawing the R and the H need to be reversed.
That’s just my 2 cents worth. Hope it helps.
Pepe
Thank you for your input Pepe; It has been many years ago that I did the basic calculations for my engine. I have stuck with the same engine size though all of my work so haven’t had a occasion to go back and look at what I did or where some of the information came from. I do recognize the chart you posted and I do believe I followed the dimensions on line D
I have convinced myself that I got a partially charred chunk of wood about the size of a tennis ball all the way to the restriction and it was stopped the flow about 60% of the restriction. This would have given weak gas. Also, I think that the O2 instead of reacting as it should it was “burning” which cause high temperatures in my cooling rail. I have only taken the wood/char out of the gasifier. I haven’t taken it apart so IF we got a little Indian summer, I could load it up and give it another try. It had been working very well until the last trip out.
In the mean time Max Gasman has graciously offered some rather major changes. I am working on another combustion/reduction section that will conform to what I think Max is suggesting and hopefully be able to just exchange the two units out for a trial with the new dimensions. TomC
I am curious of your findings Tom. The more I learn about all this the more I realize how important wood sizing is. I like that you’ll be able to swap the new with the old and be able to see what the difference is.