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  • Reverse flow Vertical

    Stumbled upon an oldie but goodie and I always wanted to ask BBQE a draft question.

    What is the main advantage of the exhaust being in the middle of the smoke chamber?

    I thought that you needed constant flow to avoid creosote buildup, have you had any issues with that?

    What is the temp difference between the top rack and the exhaust level?

    Would there be any advantage to have two sets of exhaust, I was thinking about one at the top shelf as well to help start a draft.

    I have to build another hybrid vertical for my oldest boy and have a real nice aluminum box to start with.

    Thanks
    Attached Files

  • #2
    Something tells me that if your exhaust is going to be that low, you would be choking the fire out..
    Ken


    I Should Have Been Rich Instead Of Being So Good Looking

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    • #3
      Right idea, needs tweaked a little.

      Need the size of the exhaust you are planning?

      Need the size of the draft openings you are planning?

      Dimensions would be good to help.

      I will see if I can model the exhaust exchange once I have dimensions. The exchange is important.

      Height gives you depth of smoke and density.
      Tour the New Rig Here!

      Sgt. USMC '79-'85

      S-M inmate number 12

      RIP ronP

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      • #4
        Hmmm...I don't have a modeling program, but I DO know that warm air wants to go up. Somthing's amiss there.
        In God I trust- All others pay cash...
        Check out the Mad Hunky and products at https://madhunkymeats.com or https://www.facebook.com/MadHunkyMeats
        Lang 60D, The Beast, 18 and 22 WSM, Brinkmann Backroads trailer, Weber 22 Kettle, gutted MB burning watts

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        • #5
          Originally posted by bbally View Post
          Right idea, needs tweaked a little.
          Take some notes, Dana...

          I won't even attempt to explain BBQ E's design, other than I KNOW it works and if I build another smoker, that's exactly the way I'll go about it. I had my smoker orginally venting right out the top, and had hell with even temp problems... I extended it down to the height of my bottom grate (using Dana's model design below), which would put it roughly where Dana has his, and it made one hell of a difference. I haven't had any issues with draft or snuffing out the fire.

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          • #6
            Originally posted by Texas-Hunter View Post
            Something tells me that if your exhaust is going to be that low, you would be choking the fire out..
            Originally posted by bbally View Post
            Right idea, needs tweaked a little.
            Originally posted by Richtee View Post
            Somthing's amiss there.
            Heh Heh Heh...wrong on all three accounts! This is the classic Backwoods design for a reverse flow vertical smoker, and I believe they do pretty well. Hot air does go upwards through the channels, and forces it's way down across the food to the exhaust...I know it sounds like WTF, but not only does it work, it works damn well. Jerod (Got14U) also built one modeled after this, and he has also reported awesome results.

            If you put an exhaust higher in the cabinet, you might as well build a UDS as it will not work the same as a true reverse flow vertical. Creosote has never been an issue. In fact, that cabinet smoker is a real power house! You can check out the entire thread at this link...

            http://www.smoked-meat.com/forum/showthread.php?t=6649
            BBQ Eng.

            The "Cow Girls" were adopted from the shelter, and found on petfinder.com.
            Adopt a homeless pet - http://www.petfinder.com
            I built the Iron Maiden - Iron Maiden Smoker Build

            Over 5000 unreadable posts...Photobucket can kiss my ass...they will never get a dime. I will not pay a ransom.

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            • #7
              Allright- I can accept that. Counter-intuitive it is tho. Sooo does it have/need a stack for draw to ensure good flow?
              In God I trust- All others pay cash...
              Check out the Mad Hunky and products at https://madhunkymeats.com or https://www.facebook.com/MadHunkyMeats
              Lang 60D, The Beast, 18 and 22 WSM, Brinkmann Backroads trailer, Weber 22 Kettle, gutted MB burning watts

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              • #8
                Originally posted by Richtee View Post
                Allright- I can accept that. Counter-intuitive it is tho. Sooo does it have/need a stack for draw to ensure good flow?
                Rich,

                I accept the fact that it is counter intuitive. In fact when I built mine, I structured the initial build so I could drill through the inside skin if it wasn't working properly, and add an outlet higher up...not only have I not had to do so, the design is so solid that I wouldn't change a thing. I do have a small stack on mine (more for asthetics than anything), but some of the backwoods smokers only have the stack the length of the back of the unit, not extending upward beyond the top of the smoker. Here are some pics of mine. I'm telling you, it is a whole lot of smoker for a smaller unit. I may be building another one with some super heavy wall stuff this summer...depending on what my neighbor wants to commission. Did you see the awesome metal buy that I stumbled into? http://www.smoked-meat.com/forum/showthread.php?t=11748





                Last edited by BBQ Engineer; 12-29-2010, 08:57 AM.
                BBQ Eng.

                The "Cow Girls" were adopted from the shelter, and found on petfinder.com.
                Adopt a homeless pet - http://www.petfinder.com
                I built the Iron Maiden - Iron Maiden Smoker Build

                Over 5000 unreadable posts...Photobucket can kiss my ass...they will never get a dime. I will not pay a ransom.

                Comment


                • #9
                  All I know is what NOT to do. Whisky Fish is the biggest fuel hog in the world. My stacks are at the top of my smoke chamber and if I wanna kill my temps, all I have to do is open those dampers. Doen't make my fire any hotter it just dumps my heat. Fortunately(for my ego) I built it before meeting you fantastic people. Had I seen Dana's design, there'd be 28 more cords of oak and 56 more bags of charcoal in this world
                  JT

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                  • #10
                    Great design! Do you use the water pan dry? How many butts will fit on one shelf? How long a burn time do you get and how many lbs of charcoal can you put in the basket?

                    Thanks,

                    Doug
                    www.nopigleftbehind.com
                    -----------------------------

                    Comment


                    • #11
                      Originally posted by gooose53 View Post
                      Great design! Do you use the water pan dry? How many butts will fit on one shelf? How long a burn time do you get and how many lbs of charcoal can you put in the basket?
                      Hey Doug,

                      I use the water pan filled...and this is a whole separate discussion topic in the much larger design question. I originally used a food service steam table pan, but man was that a PITA to clean up. So, I built an insert that fit a standard 1/2 size disposable foil pan. Here's where I figured out how much it affects performance. Originally I had a bit of clearance between the bottom of the pan and the insert baffle that it set inside. The temps were super hot compared to what I was used to. So I shortened the depth a bit so the foil pan contacted the bottom plate and Viola' it was back to what I had become accustomed to with the food service pan. So, this small alteration can give extreme flexibility...pan touches the bottom baffle, the water acts as a giant heat sink and stabilizes temps dramatically. More fuel is used, but man is it predictable. Water pan does not touch the bottom baffle, super efficient for charcoal usage, and you can really crank the internal temps for say, chicken or turkey which like a hotter smoker temp. In this mode, it must be dampered WAY WAY back, and charcoal use is really next to nothing...seriously.

                      I can fit a couple of butts on each shelf. I may build a much bigger one this summer that isn't double walled and insulated...but for me and the lovely and talented Mrs. Engineer, more than a single butt and I'm eating freezer leftovers for a long time.

                      My unit (without a side wall on the fire pan) can maybe hold a chimney and a half of charcoal. With the water pan touching the bottom of the baffle plate it will last 6-8 hours depending on the charcoal I use. If the water pan is elevated above the bottom baffle plate you have to damper it back so much, that at the end of your smoke, the charcoal would need to be snuffed out and you could use it in the next chimney to start the next fire. For the one I gave my brother with an actual basket for charcoal...it will hold more than you would ever need for a single smoke, even with the water pan contacting the baffle plate. You can also minion method the hell outta a smoker like this.

                      Hope this answers your questions.
                      BBQ Eng.

                      The "Cow Girls" were adopted from the shelter, and found on petfinder.com.
                      Adopt a homeless pet - http://www.petfinder.com
                      I built the Iron Maiden - Iron Maiden Smoker Build

                      Over 5000 unreadable posts...Photobucket can kiss my ass...they will never get a dime. I will not pay a ransom.

                      Comment


                      • #12
                        i'll have to keep that in mind about the water pan. the dimensions on my fridge smoker will call for a ss restaurant pan sitting directly on a commercial cookie sheet. i'll have to crank it up & mess around w/ heights for it.
                        brink vertical charcoal(the carp)
                        18" old smokey charcoal grill/smoker
                        cast iron Hibachi
                        22" Kettle w/ "Smoke-EZ" styled riser extension
                        & rotisserator
                        12x7 wells cargo vending trailer(mods in progress)
                        stuffer,slicer & more carp than i can fit in it...
                        Marshall amps & various awesome guitars,drums,P.A.,etc.recording studio.....

                        Blues-N-Cues Concessions & Catering
                        http://blues-n-cuesbbq.com/
                        my music recordings-
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                        • #13
                          As I said right idea, needs tweaked a little.

                          There is a difference between cooking food with something that gets hot and a properly engineered system, let me have the dimensions, I will let you know what the program spits out.
                          Tour the New Rig Here!

                          Sgt. USMC '79-'85

                          S-M inmate number 12

                          RIP ronP

                          Comment


                          • #14
                            Originally posted by BBQ Engineer View Post
                            Hey Doug,

                            I use the water pan filled...and this is a whole separate discussion topic in the much larger design question. I originally used a food service steam table pan, but man was that a PITA to clean up. So, I built an insert that fit a standard 1/2 size disposable foil pan. Here's where I figured out how much it affects performance. Originally I had a bit of clearance between the bottom of the pan and the insert baffle that it set inside. The temps were super hot compared to what I was used to. So I shortened the depth a bit so the foil pan contacted the bottom plate and Viola' it was back to what I had become accustomed to with the food service pan. So, this small alteration can give extreme flexibility...pan touches the bottom baffle, the water acts as a giant heat sink and stabilizes temps dramatically. More fuel is used, but man is it predictable. Water pan does not touch the bottom baffle, super efficient for charcoal usage, and you can really crank the internal temps for say, chicken or turkey which like a hotter smoker temp. In this mode, it must be dampered WAY WAY back, and charcoal use is really next to nothing...seriously.

                            I can fit a couple of butts on each shelf. I may build a much bigger one this summer that isn't double walled and insulated...but for me and the lovely and talented Mrs. Engineer, more than a single butt and I'm eating freezer leftovers for a long time.

                            My unit (without a side wall on the fire pan) can maybe hold a chimney and a half of charcoal. With the water pan touching the bottom of the baffle plate it will last 6-8 hours depending on the charcoal I use. If the water pan is elevated above the bottom baffle plate you have to damper it back so much, that at the end of your smoke, the charcoal would need to be snuffed out and you could use it in the next chimney to start the next fire. For the one I gave my brother with an actual basket for charcoal...it will hold more than you would ever need for a single smoke, even with the water pan contacting the baffle plate. You can also minion method the hell outta a smoker like this.

                            Hope this answers your questions.
                            It does thanks. The reason for the water pan empty question was I used a similar cooker a few times in comps and no water pan was needed. In fact the builder said it made it too moist in the cooker... never tested it.....took his word. I like the idea of reverse flow...I have a large pig cooker that is rv and it does a great job.
                            www.nopigleftbehind.com
                            -----------------------------

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                            • #15
                              Originally posted by bbally View Post
                              As I said right idea, needs tweaked a little.

                              There is a difference between cooking food with something that gets hot and a properly engineered system, let me have the dimensions, I will let you know.
                              Bob, I have to hand it to you…that barely sounded arrogant or dismissive at all! Imagine my embarrassment that I didn’t consult you when I began my build…I had no idea that you held the only copy of the perfect smoker design.

                              In all seriousness, really? You are suggesting that since you have a “program” that you are the only arbiter of what will work? I can assure you that as someone that accepts and rejects engineering “theoretical” designs for aircraft parts on a daily basis and for a living, in many instances what looks good on paper or on a modeling program doesn’t perform well at all in real world conditions. If I accepted theoretical designs only, I can guarantee you that you wouldn’t be able to have a decent conversation outdoors over the sound of aircraft hitting the ground. So I suggest that you lose the arrogance, take the theory of your “modeling program” with a grain of salt, and come back to earth to walk amongst the rest of us mere mortals. This may come as a shock, but you don’t hold the golden key…none of us do.
                              BBQ Eng.

                              The "Cow Girls" were adopted from the shelter, and found on petfinder.com.
                              Adopt a homeless pet - http://www.petfinder.com
                              I built the Iron Maiden - Iron Maiden Smoker Build

                              Over 5000 unreadable posts...Photobucket can kiss my ass...they will never get a dime. I will not pay a ransom.

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