Sqaure stack question

[kdfiter]

I building a reverse flow out of a 32 gallon air compressor tank ..I went to Feldons calculator and I put in 3.5" for a round stack and it said it should be 18.64 long ...I was going to use a 4" sqaure stack ..should I use the Same measurements or would it be shorter ..thanks fir any advice ..I did try finding some sort of calculator for sqaure stack and couldn't find any thing

 

[pete mazz]

https://planetcalc.com/6097/

 

[kdfiter]

Thank you ..I did the calculations and it said I need a 12 in stack ..thanks again

 

[civilsmoker]

I would recommend you use a 30inch stack (4" square is equal to 4" round when losses are considered), smaller smokers need oversized flow areas because of the higher friction.

 

[kdfiter]

30in stack ? I used feldon and it said I need 180 cu in in volume so I punched it in the sqaure stack cacultor and it say a 12 in stack are these cacultors off that much

 

[civilsmoker]

Yes they are off for smaller smokers. I am just finishing up a 33 gal compressor build with a 30" 4" round and I wouldn't go any smaller.

I would recommend you review the tutorial here cause it was developed not just on therory but adjusted based on actual builds

 

[kdfiter]

Thanks for the advice .I'll go with the longer

 

[kmmamm]

Any reason you wouldn't consider going with a 6" stack? The 6" will flow 3x more than a 4". It is a lot easier to tune (restrict) flow with the larger diameter stack than trying to increase the flow of a smaller diameter.

 

[kdfiter]

I was going to go with the 4" sqaure tubing because I had gotten it for free..I dont have any 6"

 

[kmmamm]

As good of reason as any. Keep in mind 4" is the outside diameter and the thicker the wall, the smaller the inside dimension will be. Couldn't hurt to check around to see if there are any 6" drops available before committing to the 4".

 

[kdfiter]

Thanks all for the good advice ..I welded the 4" sqaure on.. it's a 20 in stack (that's the longest I had) ..I'm gonna have to scrounge up another 10" to hit the 30" height ..I was thinking with the 6" that might be a little tougher to mount on to my smoker (-it's a smaller tank) here is a picture of the one I'm working now....ATTACH=full]377299[/ATTACH] ..

 

[civilsmoker]

The volume/length of a stack is about achieving the proper draft. The length allows for a pressure differential that aids in proper flow.

As an FYI, I have that same tank in my garage just waiting for my next build......