500 gallon RF Build revised

Discussion in 'Reverse Flow' started by nwbhoss, Mar 2, 2016.

  1. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    From post #8......    Looks like the stack that gave the best numbers was a 9" dia. x 39" above the CC....

    http://www.smokingmeatforums.com/t/...others-ready-to-use-rev5-6-19-15#post_1264161

    http://www.1728.org/circsect.htm

    Mark, afternoon.....   First, when looking at the tutorial for building a RF smoker, ONLY use the first post......  IGNORE the other posts for the build...

    The first post is a step by step how to calculate each number for the build....

    Gallons x 231 = 115,000 cubic inches..

    115,000 X 0.004 =  460 cu. in.  FB/CC opening / area under the RF plate / area at end of RF plate...

    115000 X 0.33 =  38,000 cu. in.  for the FB.... (24 x 40 pipe is 18,000 ) too small  (36x36x36 is a great size)

    115,000 X 0.001 = 115 sq. in. for the FB inlets...

    115,000 X ( .017 to .022 ) = 2,000 to 2,500 cu. in..  I lean toward the larger volume to insure good air flow..

    Exhaust Stack Volume ...

    2500  / 0.7854 = 3180 cu. in. / 81 (9x9) = 39" of stack ABOVE the Cook Chamber...   That's what I would use....

    FB/CC opening...

    Inside diameter of your tank is approx. 36" ...  use 18" for the radius.....

    16" segment height works well...   but it can be safely lowered to give more room where the food is cooked....  Because the diameter of the CC is wide, there is reduced friction.....  Also, if you slide the FB into the CC, that will reduce surface area and friction loss under the RF plate...

    I would slide the FB into the CC until it has passed the welded bead so you are now into the straight section of the tank...   That will make this build soooo much easier...  the RF plate will now be a rectangle, the friction will be reduced and I'm going to say the Segment Height can be reduced to 14", giving you 21" above the RF plate for food racks...    The RF plate width will then be 35"...  It can then be welded directly to the top plate on the FB for easy fitment and the FB will be 1" wider than the CC for easy fitment...

    For the air inlets to the FB, I would put ~20 sq. in. of opening directly across from the FB/CC opening ...

    I would put ~80-90 sq. in. about 4-5" above the floor of the FB and have the wood grate about 6-7" above the floor of the FB....
     
  2. nwbhoss

    nwbhoss Smoking Fanatic

    Thanks for doing my research for me again Dave. I hate that the numbers part if this stuff still baffles me. So I don't know if I can fit a 8" let alone 9" stack on the plenum I built (again poor planning on my part) and at 39" if I went with a smaller one I would be way too tall and inefficient I am sure. What about the option of 2 5" stacks? I could run one just like I have in the picture and a 90° elbow below it?
     
    Last edited: Aug 3, 2016
  3. Looks tight but an 8" may fit  Couldn't really tell from the pic.

    I calculate that a 500 gal. smoker needs a 48 -50 inch tall 8 inch stack

    Gary
     
  4. nwbhoss

    nwbhoss Smoking Fanatic

    I think I can fit a 8" with some modifications. I did not weld the top of the plenum to the smoker in case I needed to notch out to make the stack fit. The top of plenum actually enters into the cook chamber about 2" so I left myself some wiggle room
     
  5. With that size smoker bigger is better     a 10 inch would need to be around 32" tall       See what looks more appealing to you.  Maybe like Dave said a 9"       I think the 8" will be too tall and won't flow nearly as well.

    You are going to have a fine smoker when you are done

    Gary
     
  6. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    2 each 7" stacks would be close to 1   9" stack... a little over...  but then you have doubled the friction...
     
  7. Personally I think one 9 or 10 inch would give you a lot cleaner look

    Gary
     
  8. nwbhoss

    nwbhoss Smoking Fanatic

    Dave and Gary thank you very much for your educated opinions! I very much appreciate it! I did kind of weld myself into a corner and make the plenum too small to support a 10" stack. I may be able to do a 9" but after stopping at my local sandblasting place to set up an appointment to have it blasted I went to the steel/fab shop next door to see if they had any pipe and ended up getting a 8"x48"x1/4" pipe for free! 

    As long as the 8" pipe flows ok I will go with it, I know shorter would be better but I also have the issue of this smoker not being outside to deal with. I am putting it into a converted barn that I am turning into an outdoor kitchen for smoking and game processing. I think I am going to need the extra height to help vent the smoke out of the room, I am at crunch time now as I have a big party on the 20th and I need this smoker running for it. If I have temp problems from the stack being too small I will have to address that after the party. I may just hedge my bet and attach a flange to the plenum that can be easily removed and tack the pipe to it so if I need to change it out I can do so.

    Thanks again for your input! I could not have built this smoker without all the help I have received here!!!!!
     
  9. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    8 x 48 for FREE is good.....
     
  10. nwbhoss

    nwbhoss Smoking Fanatic

    And it's 1/4 inch wall not the cheap thin stuff I would have used.

    It's all loaded up and ready to head to the sandblaster today! He quoted me $300.00 to do the whole thing inside and out.
     
  11. nwbhoss

    nwbhoss Smoking Fanatic

    [​IMG]

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  12. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    Too bad you had to settle for a Duckworth....  That's what I settled on too....    What a great boat... [​IMG]
     
  13. Can't wait to see it blasted and painted.  One thing that concerns me is the ground clearance on the FB. You will have to careful going in and out of drives.

    Gary
     
  14. nwbhoss

    nwbhoss Smoking Fanatic

    The smoker is not staying on that trailer it was just so I could move it around in my shop. I am putting it on a stand in my barn that I am converting into a outdoor kitchen with stainless counters and sinks a fridge and I am going to build a small smokehouse for salmon out of one room. It will also have a butcher room for game with my band saw and grinders etc.
     
  15. nwbhoss

    nwbhoss Smoking Fanatic

    I love that boat!! One of the best purchases I ever made. It is getting a repower with a 200hp Yamaha soon and I am adding a offshore bracket.
     
  16. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    I built an offshore bracket for mine....  It's awesome.....  I'll send you some pics.....
     
  17. nwbhoss

    nwbhoss Smoking Fanatic

    I would love to see them!
     
  18. tjmitche

    tjmitche Smoke Blower

    The smoker is not staying on that trailer it was just so I could move it around in my shop. I am putting it on a stand in my barn that I am converting into a outdoor kitchen with stainless counters and sinks a fridge and I am going to build a small smokehouse for salmon out of one room. It will also have a butcher room for game with my band saw and grinders etc.

    Now that you've gotta send pics of!! :)
     
    Last edited: Aug 2, 2016
  19. nwbhoss

    nwbhoss Smoking Fanatic

    Will do! When its done it will have a cutting room for cleaning fish and processing game and butchering (I have raised pigs in the past and plan to again this time making all my own bacon and ham etc....) When I was kid we had a smokehouse for salmon and used racks attached to pulleys to hoist them up about 10 feet in the air (the house was 4'x4'x12' tall and build a small alder fire in the bottom to smoke. I plan to do something similar but with only 8ft ceilings it wont be exactly the same. My crab cooker will be in there as well 

    The big stick burner and my little propane smoker will be in one side and a large area to store wood for the stick burner. I have a truckload of Cherry a friend brought over from their Eastern Washington orchard sitting in there waiting now! He is going to bring me a load of apple as well. 

    It should be pretty cool when its done
     
  20. ahumadora

    ahumadora Smoking Fanatic

    Reading this post is getting me ramped up ready to work on the 2 x 500 gallons I have sitting at the shop.

    I had a crazy idea to cut the sides out of them and weld them together to make a 1000 gallon, That way I could use one big grate to slidebetween the 2 smokers,

    But I think it would be too much smoker for around here.

    At the moment I am working on another 250 gallon and should be close to done by Friday night.

    After that I will probably build a 100x80x180cm insulted vertical before I tackle the 500 gallons.


    The 250 Gallon I am building at the moment.

     
    Last edited: Aug 3, 2016

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