[Gasification] First run of passive draft (TLUD) gasifier stove successful

[Jonathan F. Pratt]

I decided to share this with the list...

Just this evening I finally got around to building myself a passive draft 
woodgas stove.  I followed the same basic design as the other woodgas 
stoves.  Tom Reed has said he has had difficulty with natural draft 
prototypes.  He could never get any that were very clean burning.

The results on the first run for mine were extremely encouraging.  However, 
I used dry store bought woodchips.  But I got an extremely clean burn and 
did not even smell smoke just a few feet from the unit.

I kept thinking in my head how to get mass produced units for humanitarian 
aid that can be shipped somewhat compactly in bulk.  This unit has no fan 
and no batteries to deal with.

I built mine out of a 5 gal steel pail, and about a 2' section of stove 
pipe.  The steel pails are stackable and can be shipped compactly.  The 
stove pipe sections (from Home depot) can of course be shipped stacked in 
bulk and easily put together into cyliners by hand.  The only difficult part 
was cutting a hole out of the lid to slip the stove pipe section into.  I'm 
sure some kind of hole punch die can be made pretty easily to do this task 
much easier than I did it with a jigsaw with metal cutting blade.  I used 
the circular disc from cutting a hole in the lid as the bottom of the 
combustion chamber, drilling a few holes into it and the bottom of the stove 
pipe and using some steel wire to hold it onto the bottom of the pipe.

I drilled all the air holes with a 1/4" bit.  All in all the dimensions of 
this unit were very similar to the Phillips stove but without the 
thermocouple powered fan and the fire tube is longer extending down to only 
2" from the bottom of the 5 gal pail.  I painted both the combustion chamber 
and the inside of the steel pail in black stove paint for durability.  The 
stove pipe (combustion chamber extended above the lid about 2") I drilled 
airholes in the pipe just below the lid.  The pipe itself extending beyond 
the lid can be made to directly support a pot with a few extra brackets for 
support and/or more holes drilled in the section that sticks out the top of 
the lid for the flame to exit.

I got a decent amount of draft from the unit as you can see in the attached 
pictures.  It was very interesting to see a layer of swirling smoke UNDER 
the flames.  Because of the smoke I couldn't even see the woodchips 
underneith.  But as I said the flames consumed all of the smoke and only 
very seldom would I see a small puff of smoke escape the combustion chamber. 
Maybe I have had good luck with this one because of the stove paint.


Best Wishes,

Jonathan Pratt
President, iENERGY Inc.
www.woodgas-stove.com