propane burner in a reverse flow

Discussion in 'Reverse Flow' started by ribwizzard, May 13, 2013.

  1. Let me get some opinions. I need to install a propane burner in a reverse flow build. I was thinking something similar to this, but am worried about the accumulation of grease causing a bad grease fire. I was thinking about going ahead and cutting some slots that allow the grease to run to the bottom of the cooking chamber, and just installing drain valve right to bottom of the cooking chamber instead of piping it to the reverse flow plate. The slots would allow the grease to run out, but wont be big enough to really effect air flow. I do not want the burner under the reverse flow plate.

    Any thoughts or suggestions?

  2. jarjarchef

    jarjarchef Master of the Pit OTBS Member

    We have 6" grills at work that have a similar setup for the burners. We have to either put water or baking soda in the drip pan below them to keep it from catching fire. With you draining the grease it might help, but you still will have thin layer that might light with the puff of O2 you get by opening the CC door. I am by no means an expert, but these grills will light up quick if we forget either water or baking soda......

    Maybe build a temp installation with removable RF Plates and try it to see what happens.
  3. Well, I have thought about doing a preforated plate instead of a reverse flow plate, and mounting the pipe under it with a deflector inbetween.
  4. 05sprcrw

    05sprcrw Smoking Fanatic

    I would think that if your deflecting it with that peak, it would be similar to a regular grill. Is there a way to catch the drippings before they get down to the flame? Maybe just have to cook with a pan under the meat to catch it instead?
  5. Ive thought about using stainless angle for the grill surface but steering away from that.  Project is to build a well performing gas grill that will aslo perform well as a smoker.  I might have to move away from reverse flow in order to do that, but Im still trying to find a way to make it work. I have installed a gas burner under my reverse flow in my large pit, and it works good as a cooker, but this needs to work as a grill that can really sear steaks. And being smaller, space to fit everything in and make it work is also a problem.
  6. thechuck

    thechuck Smoke Blower

    I know this sounds a little crazy but here goes... if you're talking about your small smoker project RW, how about having the lower opposite FB end of the CC be removable with the different attachments built in. Various different ways to do this but whats in my mind is having roughly the last third of the end cap be a removable plate where you could take it off and slide out the rf plate (or possibly have it as one unit that slides out as a whole if you're talking a smaller scale) and then have a "propane attachment" that would have a separate end cap with a complete propane burner slide in. As in, the propane burner attachment endcap could have the gas fitting/hose attachment coming out to attach the bottle and the tube burner, along with top deflection plate and bottom grease deflection plate, that slides in as a unit. Of course you need certain brackets in places but overall would possibly give you the best of both worlds without having to change the whole unit.

    All this is making sense in my head along with the layout... hope you can picture it as well. If its not making sense I could throw together some sketches. Or if it's not feasible, then move along...  [​IMG]
  7. 05sprcrw

    05sprcrw Smoking Fanatic

    It may be a bit complicated but what if you had the rf plate hinge up so that it interlocks and acts like a regular cooker, and they can drop them down and out of the way when they want to grill, that would dump the drippings to the bottom away from the flame and allow direct heat?
  8. thechuck

    thechuck Smoke Blower

    Actually I take back the design I said (for the most part, still has its uses)... the reason I had it removable was to allow for the gas piping without having an always built in fitting. But you wouldn't need all that cause you essentially already have an opening, the FB. So why couldn't you have a drain on the bottom of the pipe, a removable RF plate, and a propane burner inset (and of course a grate for charcoal use). If the propane inset was a unit that you could place in after you pulled the RF plate out and have it sit on the same brackets. Have the pipe burner with attached heat deflector above it and if you're concerned about grease then have a thin v-plate below it that pushes the grease to the sides and then gaps to let it drain to the bottom of the pipe (as like what most gas grills with grease traps have). As part of the attachment, have your burner piped thru a plate that'll also close of the FB opening and then go thru the FB to a propane bottle, so no grease can get in there and no heat loss.

    You yourself said space was an issue in this small of a smoker/grill, so I think a perforated RF plate with the burner above it would start to encroach (sp?) on your rack/grill area, and increase the chances of a grease fire.
    Last edited: May 13, 2013
  9. This is a seperate build from the other, just wanted to clear that up.  It will be 16 inch diameter, 32 long cooking chamber with 16 inch firebox, simular to the others and Im using the same firebox design as the others. 

    Difference is , this one will primarily be a propane grill.  I was thinking going with a 28 x 3/4 inch pipe burner and high ( about 15psi ) regulator would allow for a single burner to crank it up pretty darn well, and I was going to plumb it in from the opposite end of the firebox. so as regulalor and ignition could all be n that end, and keep the bottle away from the firebox.  I'd like to stay away from a lot of removable parts, just becouse I dont want it to complicated.  But I want it to be able to fire up the propane grill regardless if the firebox is going or not.  and that also limits using attachments.

    I am on the same though as theChuck in as far as designing it to deflect the grease away from the burner, using v plates and such,   an easy fix would be to "pipe" the heat under the cooking chamber to the other end , basically using the bottom of the cooking chamber as the reverse flow plate, by welding a piece of chanel to the bottom, but I just dont think it would be very attractive.

    I'm going to have to get my head around how to design the v plates and where to deflect the grease to,  its just I dont have much experience making gas grills, I always bought those.  And they look like they keep a lot of distance between the burner and the cooking grate.
  10. thechuck

    thechuck Smoke Blower

    Do you plan on always having the burner hooked up and attached? Do you plan on having a damper or anything to block the FB opening when in grill use?

    I have a couple ideas that I may sketch up...
  11. Yes, there will be a dampner on the firebox opening, and this effects the reverse flow plate shape at that end, becouse it will need room for the dampner to open.  Id like the burner to stay attached. By going 3/4 stanless tubing, it will probably be welded in place.

    Id like to see your scetches of your ideals,   Thanks
  12. thechuck

    thechuck Smoke Blower

    Do you have "ideal" measurements all figured up already? FB opening (height), RF height and thickness, how far above the burner are the racks, etc...
  13. The firebox and dampner are set becouse Im just using one from the other builds. It puts the top of the dampner door 6 inches from bottom of the cooking chamber. That means the right 6 inches of the reverse flow plate has to be fairly flat to allow it to open all the way.

    Other than that, 3/4 pipe o.d. for burner, and Id like the cooking grate to sit dead center of the 15.5 diameter. so 7.75 from the bottom. less 1/2" for grate, leave 7.25 from bottom to fit burner and what ever plates I come up with, and I dont want the grate to sit right on the plate either.

    I know, its a lot of stuff to fit in a small 1/2 pie shape area, thats why I can get my head around it yet.
  14. thechuck

    thechuck Smoke Blower

    So the FB opening (half moon segment height) and dampner are 6" tall?!? or am I misunderstanding?
  15. [​IMG]
  16. thechuck

    thechuck Smoke Blower

    So if I understand... the damper door is 2" above the top of the 4" opening (6" total) and would hinge into the CC?
  17. I'm not seeing why you wouldn't be able to put a drain in the rf plate and route it out through the cc. If you use a big enough ball valve you'd be able to let the fodder fall through. Welded top and bottom, the only compromise to your rf would be the piece of pipe running vertically below it. If you segmented the rf plate angling towards the drain on four planes, you really shouldn't accumulate much grease, and being in four sections, each would be reasonably short/narrow not requiring too much pitch. Reflected heat might vary a bit I suppose, but I wouldn't think it would be much. If you're making your own burner, you could simply not drill the section in th cc not over the rf plate. Don't know if that helps or I'm not seeing the problem completely...
  18. Well, DoodleQ

    I might be overthinking it, but I do not want the burner so close to the grease, and if I install it inder the reverse flow plate, Im thinking it will get the plate hot enough to flame up the grease as well.

    I was looking at it again last night and Im thinking something like this. Diverting the heat from the firebox down both sides, and leaving the center for the burner assembly would allow the grease to run to the bottom of the cooking chamber and keep enough distance from the burner. The center section would be slotted just like a diverter on a gas grill.

  19. radioguy

    radioguy Smoking Fanatic


    Here is something along the lines that TheChuck suggested.  I'm not sure how complex you want to get.  This guy has a detachable burner assembly. 

    It amazing looks like your first picture.

    I'm not sure if that YouTube link will work, if not then search this subject

    Unique Design Barbecue Smoker- BBQ Pit - Gas Grill

    Hope this helps out
  20. thechuck

    thechuck Smoke Blower

    RadioGuy... that's very similar to my original idea! But I understand where RW is coming from in wanting it as simple and complete as possible... but I definitely see the benefit of separate attachments to create a specific unit as a whole.

    RW, I think we're close to the same page. I didn't get a chance to draw it up but your drawing is similar to what I was thinking (with a W or M shape for the RF plate). The damper door keeps throwing me off tho cause I don't know exactly how much it'll get in the way. On your current design, I'd still worry about your flame being that close to grease in that confined space even tho it has a drain. With your design above, I would almost move your burner up and have that top ^ be the actual deflector plate for the burner, then have another ^ (wouldn't have to be much of a peak/angle) at the very bottom with gaps/slots along the side. This would allow grease to drip down thru the slots into the underneath side of the plate so if it builds up at all while its draining, it'll have no direct source to a flame.

    Again... just ideas

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