[Stoves] FXJ Burner - 3 photos of work in progress w/ comments

[Jock Gill]

This is work in progress that I hope you will find interesting.  Perhaps it will give you some ideas for your own work.



I get this quality of result now from what I will call the FXJ Burner.

The whole system is very sensitive, at least in a 3 inch diameter TLUD.

Primary air: 18 ports made with a 3/32s drill bit.

Secondary air: 17 secondary air ports @ 5/16s.  An increase of just 1/16th of an inch made a huge difference.

System air:  Outer can with three ports made with a can opener with three additional ports drilled out at 5/16.  These ports are around the bottom of the outer can - formerly a pineapple juice can.  Note: This configuration was hard to start and had to be restarted after 5 monutes.  The solution is to slightly reduce the amount of air coming in from the bottom of the outer can. It will be more controllable if the can opener cuts are replaced with drilled holes.  I will try six, evenly spaced holes at 5/16ths and go from there.

Operating the reactor in an outside can with 6 system air supply holes around the bottom did not work well at all.  Switching to an outer can with only 3 system air supply holes worked very well. But still a bit "hot".  The system turns out to be very sensitive to the ratio of air coming in from the top vs the bottom.

Results from the above:

Fuel load: 150 grams of old wood pellets
Run time: ~ 51 minutes, give or take a bit. The restart made times approximate.
Charcoal yield:  just under 19%, rounds up to 19%.  
	(Smelled clean and washed off easily. Very little ash in the rinse water.)

There was was a period of about 13 minutes when orange flames were slightly to fully visible to slightly visible coming out of the top of the draft enhancing can.  That is, about 75% of the run was well behaved.  After the red/orange flames retreated back into the draft tube, the flames at the burner continued for another two [2] plus minutes as the pyrolysis completed and faded out.  There was an insignificant amount of smoke at the end of pyrolysis.

The new FXJ burner design is very simple.  It looks like this:



In use, all of the parts would be centered properly.  Clearly a shorter bolt could be used.  This one is 3 inches long and extends somewhat down into the fuel bed.  Both washers are 2 inches in diameter. Copper pipe is ¾ of an inch in diameter.  Placed inside the TLUD, this creates a very effective combustion chamber -- as you can see from the first photo.  




The bottom washer is positioned a little below the 17 secondary air ports [5/16ths].

The top of the FXJ extends into the bottom of the draft can.

Suffice it so say, this burner greatly reduced the quantity and amount of time red flames exited the top of the draft can, no flames were running up the side of the reactor can, essentially all of the flames were contained in the combustion chamber, the run time was extended nicely. All in all a nicely behaved natural draft system with no moving parts.

I really hope others will try this FXJ burner design and see what it can do for them.  Have any of you seen a burner like this before?

Thoughts?  Comments?  Suggestions?

Cheers,

Jock

Jock Gill
P.O. Box 3
Peacham,  VT 05862

Cell: (617) 449-8111

google.com/+JockGill

:> Extract CO2 from the atmosphere! <:

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