thomas rubino wrote:By using a piece of angle , held in place by the last two angled bricks. This would deflect possible sparks but not impede the airflow!
Is this correct ?
thomas rubino wrote:I am wondering if my primary air hole is large enough? I went with 5" wide by 1.25 tall = 6.25 " The secondary air is 1.75 x 3.5 = 6.12"
I am getting a complete burn with very little ash left at the end, so maybe those are the correct sizes? I believe I followed your parameters.
It just feels like it would burn even better with a larger primary air. Or would adding extra primary air change the burn to be less than optimal?
thomas rubino wrote:Hi All ;
Took the dragon out for a long flight this morning! Five loads of fuel later... We were cruising!
My shop was warmer than it has ever been! Admittedly it was in the 40's outside.
Barrel temps of 320 on the lower and 465 on the upper.
Brick bell temps were 120 near the barrel and 90's down at the floor. Those numbers would have continued to rise had I kept burning.
Exhaust stack, gas temperature , checked with a T & G dragon breath monitor, reached 145 F at the end of the last load.That is significantly lower than I was getting before with a single barrel.
That temperature would also have continued to rise.
After the last load went out. I fabricated a ceramic board plug to seal my primary air off when not burning. The secondary air just got a piece of cf board propped in front.
Both will help keep all that generated heat right there in my mass and not being sucked up the chimney.
thomas rubino wrote:
This same bell with an 8" J tube and 1 barrel ran flue gas temps of 250 + After it was warmed up.
I would hope a 7" batch can support one extra barrel over a J tube?
A 9" stove eh! Wow that's a big one. Peter suggested to me that an 8" might be to large.
Peter van den Berg wrote:The primary air is large enough, on average it's about 25% of a round riser, in your case 4.9" sq. That said, in my own 6" system the combined air inlet is 24.5% at most. My heater is presumably running with lower air excess and efficiency should be higher as a consequence. Yours will run fine as it is, given the low exhaust temperatures. Keep the thing running day by day until it's getting too warm outside, sensible conclusions about this setup can be drawn when running in period is done.