Proofing ESV Calculations for the 63.3 Gallon Tank.

[Malcolm B]

Hey everyone,

Much has changed since I last posted. I've been busy working away on the smoker, using your tips, calculations and ideas. I'm getting closer towards the end now. Just last weekend I installed the reverse flow baffle plate with a sloped drain away from the F.B.



So far, this is how it sits. The F.B. handle is unfinished as I'm planning on worrying about minor details like that later on.



This is the baffle plate. The drain is beneath the center-most part of the four plates. I haven't drilled the hole, yet.



This was taken of the F.B. inlets and door before it was welded to the tank. I haven't yet installed the upper air inlet, but still plan to.

So back to the topic at hand; I just want someone to check my calculations.

CC volume: 14622 Cid.
FB to CC opening: 58 Cid (calculated) 69 (actual) I made sure that the reverse flow opening to CC from underneath the baffle was at least the same volume as the FB to CC opening. I think it may be slightly larger actually.
ESV: 322 Cid (calculated) 380 Cid (based on 18% larger FB to CC opening).

If those are correct. I could use 35" of 3.75" (I.D.) pipe to get an ESV of around 386 Cid. I also plan to make a plenum for it, so the actual length will be much longer than 35", but that is from the top of the CC. Thanks in advance for the help!

 

[daveomak]

You could also use a 4" ID pipe 35" above the CC... Don't figure in the plenum... The ESV is based on friction from the pipe... Less friction is mobetta...

 

[Malcolm B]

Thanks Dave! 4" would look more proportionate too. I can do that.

Is 36" above the CC an ideal length or optimum flow? If the pipe were shortened by 6" or even 12" would it reduce the ability for an adequate draw?

 

[daveomak]

Yes... The height of the stack is what creates draft.. From the research, it appears 35-36" above the CC is what worked very well...
It's the diameter that determines the amount of friction in the stack.