Fire box under cook chamber

[mortimersnerd]

I'm building a compact reverse flow smoker out of a 22 gallon compressor tank. Fire box will be 14"x14"x10". Since I'm trying to keep the footprint small I'm considering placing the fire box under the cook chamber, then connecting the two with a piece of 3x5 rectangular tube. I'd have the fire box intake at the bottom side on one end, and the connecting tube on the top in the opposite corner of the firebox. Is this a terrible idea? Not sure if the additional bend in the airflow will slow the air movement through the smoker too much.

[Pete Mazz]

Using that setup I would oversize the throat. The 3 x 5 tubing restricts airflow too much. Try to get something 4" wide if you can.

[Big T]

[Rodcrafter]

The only thing I would change is the air intakes would be on both ends, I would use something that could seal well like 2" valves. Then I would put 2 of those 3x5 tubes back to back in the center just long enough to weld them in place.

I said all the because you never know which way the wind is blowing, so you don't have to turn your smoker around. As for the 3x5 tube back to back will be a nice amount of air flow. Centering them will mean you don't have to have an full running fire to get the CC hot as you want. I would also put a BP above that opening.

jm2cw


Making memories.

[bbroper]

I did something similar and Gizmo suggested using a tapered chamber to connect the fire box to the CC. JMTCW

[mortimersnerd]

I could make that happen. What's the benefit of the tapered connection over a straight one?

[bbroper]

Here is from Gizmo...

I think the throat opening is partially based on the assumption that the FB is hooked directly to the CC. I don't think the calculations would quite directly apply from any standard pit calculator. Maybe start there as a best guesstimate.

Another trick might be to taper the transfer tube to help maintain flow rate like they do in HVAC ductwork. Put the larger end at the FB and the smaller end at the CC. It would act like a venturi in a carburetor. I would keep the CC opening area at the recommended throat size from the pit calc then enlarge the opening at the firebox some. How much is a guess but maybe 1.5 or 2 to 1 ratio (area) …. ?

[bbroper]

Here is what mine looks like.

Firebox connection