help with reverse flow build. Will paypal you a case of beer ;)

[DennisC]

So im looking for someone to help me do a design, im a nutter when it comes to calculating all that stuff. So id rather donate some beer to the cause! if someone is bored in these quaranteen times.


So i got a 132 Gallon tank, i want to cut into 2. and make 2 smokers. reverse flow.
so 66 Gallon each. "roughly"

So the tanks will be
42.32 Inc long
21.65 diameter "

I will do the firebox as a square, as i got alot of plate to use.

The legs will be square Square bar.

i want to be able to put in 2 racks for meat.


Anyone up for the challenge :=)?

To draw the sketch and dimensions.

Case of beer up for grabs ;P

 

[sawhorseray]

PM daveomak , he might be able to help. RAY

 

[daveomak]

The diameter is 55" ???

 

[DennisC]

wops forgot to change that into ". that was CM:P so the diameter would be 21.65354331 "

 

[daveomak]

Standard Reverse Flow Smoker Calculator... by DaveOmak and others... Ready to use.. rev5.. 6/19/15.

Here's to "Alien BBQ" and the folks that first put the calculator together and "1728 Software Systems" for this great "Circle Calculator" and all the folks at "SmokingMeatForums", with a special shout out to Ribwizzard, that contributed their ideas and feedback while this thing was coming...

www.smokingmeatforums.com

The above tutorial is what I'll use to do the calculations.... Back in a bit....

 

[DennisC]

No rush going to work now. Ill be back on tomorrow :)

 

[daveomak]

So the tanks will be
42.32 Inc long
21.65 diameter "

Diameter X Diameter X 0.7854 X Length = Volume in cubic inches
21x21x.7854x42= 14,547 cu. in.
Volume in cubic inches X 0.004 = FB/CC opening in square inches
14547x.004 = 58 sq. in
Volume in cubic inches X 0.004 = Area under the RF plate in square inches
58 sq. in
Volume in cubic inches X 0.004 = Area required at the end of the RF plate in square inches
58 sq. in
Volume in cubic inches X 0.33 = minimum volume of the Fire Box
14547x.33= 4800 cu. in..
FB size....
20" wide at the CC...
16" tall at the CC....
20" length to accommodate fire wood...

ESV.. 14547 x 0.22 = 320 cu. in.
Stack.... 320 / ( .7854 x 4 x 4 ) = 11" tall stack... THAT WON'T WORK ..... make it 36" tall.... Taller is just fine...

FB/CC opening... ED...5"... mesure up from the bottom of the CC.... Draw a straight line at that point like AB... 90 deg. to OD.... The opening will be the green area... The outside of the CC should match the arc you draw of theFB..
Do the same on the FB side that faces the CC... Measure down 5" from the top of the FB... From the center of the top, where you measured down, draw an arc that has an 11.5" radius...
The CC should look like the circle with the green segment...
The green segment will be cut in the top of the end of the FB that faces the CC... They should match up...

Any of that make sense ??

Donate to your local food bank.... or Wounded Warriors....

Glad I could help.... I'm still here to answer any questions..

Dave...

 

[DennisC]

Think so will have a proper read tomorrow.
How would you attach the stack ? Just make like a triangle piece on the side of the CC? And what diameter on the stack ? And how big of an opening from CC to stack.

Also what about the vent on the FB how big should that be? Any chance you could draw a quick sketch for best vent option on FB?


And i thought about firebricks in the FB would that affect the size required ?

 

[daveomak]

4" exhaust stack ~36" above the CC...
air inlets to the FB, ~15 sq. in.. 20% upper .. 80% lower...
1" firebrick won't affect too much...

 

[DennisC]

Few more questions.
Volume in cubic inches X 0.004 = Area under the RF plate in square inches
58 sq. in
#This is the one that really baffles me. makes no sense to me#

Volume in cubic inches X 0.004 = Area required at the end of the RF plate in square inches
58 sq. in
# If my tank is 21" wide, how wide should the RF plate be? so it gets put the right height. #

Not sure how to calculate that. any other way you can tell me ? so this dummy here gets it.
and maybe a picture so i can see how its done aswell?

 

[DennisC]

Also a side question. If i choose to do a normal offset in one of them. Can i use the same size stack and firebox and openings and such?

 

[daveomak]

Few more questions.
Volume in cubic inches X 0.004 = Area under the RF plate in square inches
58 sq. in
#This is the one that really baffles me. makes no sense to me#
I shortened the calculation by omitting all the BS to get to that point ...

Volume in cubic inches X 0.004 = Area required at the end of the RF plate in square inches
58 sq. in
# If my tank is 21" wide, how wide should the RF plate be? so it gets put the right height. #

Not sure how to calculate that. any other way you can tell me ? so this dummy here gets it.
and maybe a picture so i can see how its done aswell?

Also a side question. If i choose to do a normal offset in one of them. Can i use the same size stack and firebox and openings and such?

For the RF plate width..... Look at the circle calculator.... Look for Chord AB in the answers column....

..

 

[sawhorseray]

You welds look gorgeous Dave, beautiful work. RAY

 

[DennisC]

ahhhh... we work in mm/cm/m here. So thats why it did confuse me abit trying to convert everything haha!
Looks good tho!


So if i will do a normal offset in one of them. Can i use the same dimensions for the firebox and openings and such? and stack size and so furth ?

 

[daveomak]

Yes....

 

[DennisC]

I have a Stainless steel plate 10mm "i think thats 25/64 ″
Would that work as RF plate? or is it to thick? and stainless steel? no go or ?

 

[daveomak]

SS expands a lot... I think more than steel... I would suggest using the same metals, for all the build, so they expand and contract the same.....

 

[DennisC]

Can i ask you another thing ? The exhaust how far up should it sit? or does that not matter? trying to figure out how far above the FB it should be. we cut the tank yesterday and work starts next week! :D

 

[daveomak]

I think the exhaust should pull from the center of the cooking zone in the CC,.

I would trim the stack flush with the interior of the CC..

 

[DennisC]

So we are getting closer to getting most done.

but baffle plates! how?
Anyone who can link how they did theirs? and how much room should there be at the end of the plate that can let the warmth up and back to the meat?

Also how thick should the metal be for the baffle plate?

but yeah please if someone could show some detailed pictures :D