Chimney Material (round or rectangular)

[mag1]

I was just checking pricing on Round tubing for a chimney, and slight sticker shock. Ok, I don't do much with steel. What do you guys use for your chimney's? I was looking at a Ø3 ID size, but in the 36" lenght or so. Are you better off using rectangular tubing, or what size walls? any input on Chimney design, material, etc...? I was basing this off Feldons #'s for a vertical RF. (this is on a vertical Tank design)

Thanks

[Sam3]

Round.
In my other life, I installed wood stoves, chimney's etc. A lot of them...
Hot air rises and does so in a "Swirling" motion. Round piping allows the warmer air to rise without restriction and creates a stronger draft more quickly.

[mag1]

OK, so round it is. Is there a particular type of tube, pipe you would want to us, wall thickness? Thanks

[Sam3]

For exterior (exposed), you would want insulated double wall "B" vent.

For lining an existing chimney, you would want a good grade of stainless. Double wall is great if you can do it. I'm sure if you google or ask a chimney pro, they could give you some more options.
There are certainly a lot more options available today than there were 30 years ago.

[mag1]

What about for a reverse flow smoker, all steel design, I'm not sure I would want an actual Chimney type Chimeny (Fire place type). I was thinking just Ø3.5" steel pipe in the 37" range. Here is a screen shot of what I'm designing up.

[Sam3]

My only concern would be the creosote build up due to the warm smoke cooling quickly, but I'm no expert with stick burners or design. Maybe someone with a little more knowledge could help.

[Richtee]

What about for a reverse flow smoker, all steel design, I'm not sure I would want an actual Chimney type Chimeny (Fire place type). I was thinking just Ø3.5" steel pipe in the 37" range. Here is a screen shot of what I'm designing up.

Yeah..why? 37" Awful long, really... Don't be too concerned with draw..as it's more a function of convection and air flow...wind direction. Airflow is key. there are formulas hmmm where is that site? Help anyone?

[mag1]

just talked to my buddie, we may just go ahead and switch it to a horizontal unit, if so, I'll basiclly copy the many other good horizontal designs out there. (the vertical is starting to look way to tippy, and by the time you get a good base, I think we will be close in size to the horizontal)
thanks all.

[Richtee]

Are we talking a stove here..or a smoker? I seem somewhat confused? Not unusual, but disconcerting.

[mag1]

Smoker, I figured it should be self exanitory being in the RF forum. No biggie, I'll figure it out.

[Richtee]

Smoker, I figured it should be self exanitory being in the RF forum. No biggie, I'll figure it out.

Well..the chimney thing threw me. I'm not the sharpest pencil in the box...

As I mentioned...exhaust is like the third thing to be concerned with. Just make it big. Perhaps the square Vs. round might matter. I don't know the laminar airflow characteristics here. I DO know you need to be more concerned with intake and internal flow. A big hole you can damper a bit is fine for the exhaust.

[mag1]

Perfect. Thanks for the info.

[Charcuteryan]

Wacha cookin? Sausages and sticks are a PIA in my horizontal. Id like a vert. I would skip the reverse part, i think thats a bunch of mumbo-jumbo. (Ill probably catch hell for that!)

[Richtee]

I would skip the reverse part, i think thats a bunch of mumbo-jumbo. (Ill probably catch hell for that!)

Ahem... INCOMING HELL!

Let's come up with a new name for them.. "infinite baffle". Because that's accurate... let the heat and smoke flow underneath the plate, evening out the heat... and flow back over on the way out. Superior design.

[Charcuteryan]

Ha! Yeah i understand if you have a side fire box. But a vert? Thats overcomplicated