Naturally Aspirated Ribbon Burner. Photo heavy.

[cbrianroll]

Great stuff guys!! This is very interesting. I like the idea of the burner letting off heat in a bigger area. The only thing im wondering is why the burners aren't even longer to cover more area. I've read the pdf on Wayne's site [blower powered)..are there any other good reads on narb setups so I can understand the relationship between plenum size and nozzlettes? Or is it all just trial and error? Thanks....

[Frosty]

Multiple outlet burners, of which the ribbon is only one shape, come in all different sizes and shapes. I made mine the size it is because it's just a little shorter than the chamber I was putting it in. Sized to fit the forge. 

An issue you might run into making the very long is uneven air fuel pressure to the outlets. The blown ribbons have a diffuser to even the pressure on the outlets. Plumbing the NA inducer into the side of the plenum evened it out nicely but I don't know how much wider would still burn evenly.

I experimented with holes drilled in 2"x4" sections screwed onto the plenum. This is how I determined how many outlets to use to balance fuel air mix velocity and flame front speed with a NA inducer's output without making too much back pressure. It's also how I determined putting the inducer on the side of the plenum diffused the fuel air evenly so I didn't need to incorporate an internal diffuser which reduced back pressure the NA inducer had to overcome.

Frosty The Lucky.

[Jbradshaw]

Is there a preferred forge shape for this type of burner? I imagine it doesn't need the swirl that a round shell will help produce. But a square interior seems to me to have a lot of wasted space in the upper corners. Maybe a "D" shaped interior? Or maybe it doesn't really matter?

[Frosty]

4 hours ago, Jbradshaw said:

Is there a preferred forge shape for this type of burner? I imagine it doesn't need the swirl that a round shell will help produce. But a square interior seems to me to have a lot of wasted space in the upper corners. Maybe a "D" shaped interior? Or maybe it doesn't really matter?

Good question. Probably, yes, no, maybe. 

I can only think of a couple circumstances where inducing a vortex in a furnace isn't desirable. A feature of solid fuel forges missing in gas forges is localized heat, everything in a gas forge gets HOT. 

However (Multiple Orifice Burners) can be virtually any shape, look at the burner on a gas range for example. Glass glory hole furnaces often use button or ring MOB burners as well as ribbons for different shape glory holes. I had to stop wanting to experiment with different shape MOBs, in fact I've forced myself to only consider ONE. . . For now. 

If you REALLY want even temp in a forge try  making the ribbon close to full length and rather than aiming the orifices straight through the block, angle them outwards like a shower head to aim the individual flames evenly. 

Also, I can't think of a good reason not to mount them where ever you want in the forge. I can think of no inherent reason to aim the flame at the floor, commercial forges often orient them parallel to the floor or lid. The Johnson Appliance forges we used in school shop classes had one top and bottom aimed opposite directions to induce a screaming strong vortex. I also have a Johnson Appliance 122A trench forge I had to buy in the lot or walk away from some real goodies. Anyway, it has 4 outlets parallel to and 2" above the floor. I've never fired it, they are notorious fuel hogs but if you need to heat commercial quantities of long stock these things are your huckleberry. And yes, you read correctly it's a MOB, a gun MOB.

Frosty The Lucky.

[Lou L]

Okay, I’m basically a kid in little league stepping up to the plate at the World Series right now...but I aim to do some experimentation and learn on the way.  I have been reading through the entirety of gas forges 101 and taking notes and have already read this thread and a number of others (at least ten) trying to collect information.

    After deciding that I want to build this burner design I considered an odd possibility.  I have a small 100 CFM  lower with relatively low static pressure sitting around doing nothing.  I think to myself, “Would it be possible to supercharge this burner by adding an air assist?”  Then I run into a comment by Mikey suggesting the same thing and I tweak a little.

I imagine that the lower pressure may not add the need for a diffuser but it may.  That aside, if I were to experiment with this idea, where would be the best place to introduce the air?

My first thought is to add a “Y” connection about two inches below the mig tip in the mixing tube.  

Then I imagine pumping air through copper tubing that enters through the current air intakes.

Is this idea complete nonsense?  Would the increase in air necessarily increase the LP consumption or can you increase air and maintian lower pressures from the propane tank?  Basically, I want to get a basis to determine whether or not I would be tilting at windmills here.

Lou

[Buzzkill]

The only reason I can see to "supercharge" a burner is to get more heat out of a smaller burner.  In order to maintain the desired forge atmosphere you have to add the right amount of air and fuel, so if you can get a neutral to slightly reducing flame at welding temps with natural aspiration it would seem to me to add a level of complexity that is unnecessary to the mix. 

Personally I'd do either NA or blown rather than a combination, but I'd be interested in seeing your results if you decide to tinker with the combo.  Someone with more knowledge in this area will have to answer the question about the best place to inject additional air, but my off the cuff reaction is that introducing air downstream of the mig tip will disrupt the natural induction of the gas stream and possibly at least partially defeat the purpose of that feature.

 

[Frosty]

Lou: I decided to make the NARB simply because I felt the need for a high static pressure blower to make a ribbon burner work was wrong. They didn't have enough outlets, the more outlets the lower the pressure necessary to push X amount of . . . whatever through it. I'll talk about why I think the real reason they require so much pressure below.

A naturally aspirated inducer like the T, Ron's EZ, Mikey's type 4, etc. are low pressure high volume.  John Emerling's gun ribbon burner (blown) burner needs high static pressure because there just aren't many outlets and if you've watched videos or seen pictures of one in operation you'll see it blowing a LOT of dragon's breath out of the forge. That says it's making a high velocity flame.

It's a balancing game. The more openings = more square inches of opening area means a slower lower pressure flow..Too slow and it back fires (burns in the plenum) because the flow velocity has fallen below the rate of propagation of the fuel air mix. Another, possibly the main reason the current gun multiple outlet burners require such high psi is because the diffuser is mounted so close to the pipe where the air is let into the plenum. It looks like it's almost blocking it. When I made the vertical inlet Plenum I put a much larger  diffuser half way across the plenum so it was was about 3/4" away from the air pipe. Worked a treat as a NA ribbon burner.

Then I put the inlet pipe on the side of the plenum so the flow wasn't aimed directly at the center burner nozzle outlets and it turned out they don't need a diffuser in that configuration. A happy coincidence is the T inducers lay flat on the forge aren't in the way, the air inlet ports are away from the forge doors and almost below them and there's zero chimney effect. SWEET.

Pick one Lou, Gun or NA. Mixing the two is only going to complicate things for no good reason. Sure putting a blower on one will force more fuel air mix per second into the forge so it will generate more BTUs per second. Good thing UNLESS the unburned mix is being forced out of the forge and burning in the air in front of it.

I honestly don't care what type, gun or NA a person uses, they both do exactly the same thing, EXACTLY, both have advantages and disadvantage. It's harder to build and tune a NA burner but when you get it right that's IT you don't have to mess with it again. More psi, more flame more gas draws the correct amount of air for a proper burn. Gun is easy to build, really easy but you have to tune it every time you want to change it's output. A little practice and it's easy to tune, really easy. The real difference is a gun is tied to electricity to run. That's it the only real difference.

 Just don't try mixing the two it isn't worth the headaches. Of course that's just my opinion I could be wrong.

Frosty The Lucky.

 

[Lou L]

My plan was to build your NARB design for use and then make a second one for playing/experimenting.  In fact, I will likely make the test one first just to get the process down.  

Question:  If I add a “Y” and then a 3” nipple to form the mixing tube, do you think that the added volume in the “Y” even when sealed off, would affect the output of the burner?  I will likely start by putting a gate on the “Y” to experiment with being able to control minute increases in air volume.  Then I may try blowing forced air in based on the results.  Either way, I assume you are dead right and I’m on a fool’s errand.  But, I’m going to learn a lot about burners in the process...I hope.

[WayneCoeArtistBlacksmith]

In my blown Ribbon Burner I have it mounted in the top, aimed straight down.  In a dimly lighted shop I can see the flames coming down about half way then half swirls to the right and half to the left so it appears that even with it aimed straight down I am getting the swirling effect.  I don't know if that would be true with a NARB.

Let me know if I can help you.

[Frosty]

Lou: Are you referring to a "Y" plumbing fitting? I didn't know about Ys they might well be worth experimenting with. I don't have a mental image of what you're talking about. I don't have a clear idea of how you plan on adding a blower to a T burner and still have a functioning burner. You need to draw me a picture of what you have in mind.

Wayne: My burners do that too it's easy to see when mounted lengthwise in a long forge. Currently they're mounted in a forge you access from the side so that swirl pattern is harder to see. My burner blocks have 3 rows of outlets, the center row flames go straight down and the flames to the sides swirl to the sides.

Does that sound like it?

Frosty The Lucky.

[Buzzkill]

2 hours ago, WayneCoeArtistBlacksmith said:

I don't know if that would be true with a NARB.

I see the same thing with my NARB pointed straight down at the floor. I only have 2 rows of outlets, but when I first light the forge I can clearly see the flames swirling on both sides of the forge.

[Frosty]

A little logical speculation tells me the pressure of the expanding gasses in the flames are seeking the  path of least resistance, away from the other flames. I can't say that IS what's happening but I'd put a few bucks on it 

Frosty The Lucky.

[Exo313]

Hey Frosty!

Did you ever try drilling out a piece of brick for your burner? Would some of the newer types of refractory brick work for this application?

[Frosty]

No.

It's fast and easy to cast the burner block, the mold is even adjustable so I can make it longer or shorter and I don't have to do anything special to connect the block and plenum, it's air tight as cast.

Maybe, let us know if you  try it.

Frosty The Lucky.

[Lou L]

Okay, Frosty, here is my ridiculous idea.  I have a 100 CFM blower that doesn’t have super high static pressure. I don’t believe it can power a regular ribbon burner but thought it might increase be fun to see if it offered increased ability for me to power a slightly larger burner or perhaps offer more tuning options.  We’ve already established that I am ignorant and this would be my way to play around with some 2x4’s, experiment and learn something.  I would make a regular burner using your formula first and use that once I get it right.

Then I may play around...

I found loads of options for every part I could imagine needing at great prices at supplyhouse.com.  Awesome web reseller so far and I even grabbed thread protectors (steel merchant couplers) super cheap.  It was better than playing games with the guys at the plumbing supply who didn’t even want to deal with me when I was buying the stuff for my bathroom remodel.  They only like contractors.

Anyway, I found a 2” wye in black iron and would attach that to the 1x1x3/4 Tee.  To that I would add a 4 or 6” nipple (thinking I may need more distance for the fuel air to mix.  I would weld nuts to the opening of each 1” opening on the tee to install governors.  I assume the governors would have to have holes in them so,it is impossible to completely shut off the draw of air through them.  The forced air would enter through the wye connector on the bottom of the burner.  

I love your NARB because it requires no power and no expensive blower.  But I figured it may be worthwhile to see if a cheap blower could be added to the design to any benefit.

Be prepared...my drawing looks like my five year old got his hands on the sketch app on the iPad.  That’s not far from true.  But I think the concept is clear enough.

It is obviously not to scale...  It is, in fact, embarrassingly bad.  But I figured it works good enough for the purpose.

I read Mikey’s post about fitting blowers in the shell and the effects of air gaps and realized that more air can often be a bad thing.  This could result in a fuel hog that burns dull red at best.  Feel free to tell me I’m tilting at windmills.  I wouldn’t share my dumb ideas with the pros if I wasn’t willing to hear that  

Lou

[Frosty]

I'll play Lou, I've been wrong so many times I'm used to it. I had to look up what a plumbing WYE is and discovered it's more of an adverb than an adjective. 

Two things:

One, the connection between the blower and the NA tube needs to be almost tangential so the blast (blown air) entrains air from the NA circuit rather than cause back pressure. Yes?  I don't see a WYE I think is acute enough but maybe?

Two, I think you're going to need a second propane jet or the blower is going to lean the mix till it won't burn at all. OR if the NA jet is large enough to supply the blower it'll be too rich to burn as a NA, probably just won't entrain enough or any air in the NA circuit at all. Just not enough velocity. The same thing in effect but two different causes. 

I think this is going to be an exercise in mating two kinds of burners and the real trick will be in making it an either or device. Do we use a barometer sensor to open the second jet when the blower kicks on or perhaps an anemometer that opens the second gas valve in increments depending on the blast metering the fuel for the correct ratio.

Does that make any sense? 

I use graph paper to make concept and working sketches it makes a big difference. I'm no sketch artist but I can make mechanical drawings. There's a BIG difference and graph paper makes it so you don't need a T square or triangles. 

This is going to be fun, I'll brainstorm with you, let you experiment and take credit. 

Frosty The Lucky.

 

[Daguy]

Has anyone experimented with using drinking straws to form the nozzlettes?  Seems they would be pretty easy to remove.  Or would the casting process deform or even crush them?

[jlpservicesinc]

4 hours ago, Frosty said:

 

This is going to be fun, I'll brainstorm with you, let you experiment and take credit. 

Frosty The Lucky.

 

I used to design intake and exhaust manifolds for turbo charged cars ( they run both NA and pressurized) .. and the complexity that comes with flow, corners , air velocity and intersections can be problematic.

The air/fuel ratios will be hard to control as it would act as a variable ventui system.. unless you can create a vacuum at the Y.

As pointed out there would need to be more fuel added for the blower or blown side of things..

More than likely you would have to change the location of the fuel injector/ orifices.

The blower would need to be on a staight tube running past the NA to act as a vacuum otherwise it would blow back up this other leg if it pressurized the burner block..

Dealling with a pressized system changes a lot of how air flows in a free environment..  the burner block would have to flow nearly the same amout of air being pushed into it or you would end up with air stacking or compressed looking for another escape route..  air can only be compressed if it has resistence..

While i think and feel with experimentation might yeild results..  the best option is to run a separate 2nd tube running it the burner in  Y..

Then choosing one or the other.. NA or Blown..

The NA has to have just the right air velocity (openings or holes) to work properly vs blown which  for a given a/f ratio can be made larger to flow the velocity to keep the dragons breath from running out of control...

Im not saying it cant be done..  i just have seen where the 2 different types of blown vs na play on different strategies and the fuel injectors for forges are very simple but also setup differently for each in terms of where located..

[Buzzkill]

1 hour ago, Daguy said:

Has anyone experimented with using drinking straws to form the nozzlettes?  Seems they would be pretty easy to remove.  Or would the casting process deform or even crush them?

I thought about it but did not try it.  Unless you packed the straws with something I think they would likely collapse. The refractory material I used wasn't flowable (much) when mixed properly and I tamped it into place before vibrating the mold.  If you can get by with just vibration then you might have a shot, but you do not want any voids in the finished burner block for obvious reasons.

[stockmaker]

2 hours ago, Daguy said:

Has anyone experimented with using drinking straws to form the nozzlettes?  Seems they would be pretty easy to remove.  Or would the casting process deform or even crush them?

I used drinking straws once, would not recommend it, they are too flimsy, it was a mess.  Keeping them vertical and in line while the refractory material was poured in was very difficult, and a couple of them lifted from the wood form. 

[Latticino]

2 hours ago, jlpservicesinc said:

Then choosing one or the other.. NA or Blown

I completely agree with this.  As Jennifer indicated the dynamics of each system are rather different, and an NA burner needs some very precise geometry to work properly as an inducer.  If you add a blower either upstream or downstream of the NA inducer it will disrupt this induction and more likely than not ruin both that operation and at best greatly reduce the air being supplied by the blower as well.  In fact, if the blower is connected downstream of the gas nozzle and there are two openings for the burner (one where the burner outlet is and one, or more, where the NA inlet is) there is nothing to keep the air gas mixture from exiting the assembly from both openings, which you really don't want.  The other potential issue with your location of blower is that if you turn it on after the NA burner gets going, and it isn't spark proof, you may have an air gas mixture inside the blower itself and have ignition there as well.

Honestly this is a really bad idea for a design and I would strongly recommend you don't experiment with it at all! 

If you have to add additional air to a NA burner, and you can't correctly modify the existing geometry by relocating the gas orifice, changing it's size, or adjusting the air inlet openings, I would suggest that you experiment with introducing some small amount of forced air into the same air opening as the NA burner uses.  This will work better with a design that has only a single air inlet port like the Ron Reil burner.

What you are proposing is nothing like Mikey's vortex burner design, which as far as I am aware is just a blown burner that uses a pancake style inline fan instead of a centrifugal blower (not to take away from his accomplishment, as there are subtleties in efficiency that he is introducing with this configuration).  As I read it, his design just has one opening for the forced air to enter, a port for the gas, and a burner outlet for the combined mixture.

[Frosty]

Alright, now we're brainstorming! 

Yes, I've used drinking straws and they don't collapse if you fill them with sand which is easy to empty when the block has set. It just pours out. Unfortunately the straws don't just peal out like I'd hoped. Crayons melt out and burn clean easily, straws make black burning plastic smoke so I went back to crayons. I couldn't find paper straws around here.

We're seeing the same basic problem with introducing a blower to a NA burner system. A turbocharger works as either because it's a transparent compressor, basically a high volume low pressure impeller fan. This could work if we use a single intake NA inducer like a Reil linear or a Side arm. This would allow the NA to draw intake air through the fan with minimum inhibition. O-K-A-Y so far. Turn on the blower however and it's a gun burner and the NA is an over complex gas jet. It could work if the connection between the two devices followed the 1:12 ratio to smooth the turbulence in NA mode. Once the blower fires up there's no reason for the NA system at all and in fact having the jet in that orientation inhibits good fuel air mixing.

While I think it CAN be done I don't see a good reason why it should as anything but an exercise.

I know I told Wayne I'd write the NARB for his site and haven't. Sorry Wayne. The block mold I've been using is a simple two half L screwed together from 2" x 2" lumber I sanded smooth. The Ls are screwed together more or less permanently. The foot of the L is the set distance about 5/15" wider than the square tubing I use for the plenum. The long section of the L is a a few inches longer so I can slide the halves back and forth to adjust the length to make the burner block I want to use. 

Using Kast-O-Lite 30 means using a serious release agent, the stuff sticks to plastic better than I'd expect, I found vegetable cooking "lard" works better than wax, spray PAM is useless as is spray pledge. Pledge is silicone not wax and Kastolite doesn't seem to think silicone is a problem to stick right through the stuff.

I haven't used LPS 3 though and that does leaves a persistent wax.

Frosty The Lucky.

[jlpservicesinc]

1 hour ago, Frosty said:

Alright, now we're brainstorming! 

Yes, I've used drinking straws and they don't collapse if you fill them with sand which is easy to empty when the block has set. It just pours out. Unfortunately the straws don't just peal out like I'd hoped. Crayons melt out and burn clean easily, straws make black burning plastic smoke so I went back to crayons. I couldn't find paper straws around here.

We're seeing the same basic problem with introducing a blower to a NA burner system. A turbocharger works as either because it's a transparent compressor, basically a high volume low pressure impeller fan. This could work if we use a single intake NA inducer like a Reil linear or a Side arm. This would allow the NA to draw intake air through the fan with minimum inhibition. O-K-A-Y so far. Turn on the blower however and it's a gun burner and the NA is an over complex gas jet. It could work if the connection between the two devices followed the 1:12 ratio to smooth the turbulence in NA mode. Once the blower fires up there's no reason for the NA system at all and in fact having the jet in that orientation inhibits good fuel air mixing.

While I think it CAN be done I don't see a good reason why it should as anything but an exercise.

I know I told Wayne I'd write the NARB for his site and haven't. Sorry Wayne. The block mold I've been using is a simple two half L screwed together from 2" x 2" lumber I sanded smooth. The Ls are screwed together more or less permanently. The foot of the L is the set distance about 5/15" wider than the square tubing I use for the plenum. The long section of the L is a a few inches longer so I can slide the halves back and forth to adjust the length to make the burner block I want to use. 

Using Kast-O-Lite 30 means using a serious release agent, the stuff sticks to plastic better than I'd expect, I found vegetable cooking "lard" works better than wax, spray PAM is useless as is spray pledge. Pledge is silicone not wax and Kastolite doesn't seem to think silicone is a problem to stick right through the stuff.

I haven't used LPS 3 though and that does leaves a persistent wax.

Frosty The Lucky.

From what I remember Frosty came up with the NARB to reduce the Dragons breath but still use a ribbon burner.. 

Ideally you would need a secondary air feeder and just add another fuel nozzle.. (a secondary jet)..  The problem again is getting the ribbon burner to flow enough air not to create pressure and send the air back up other NA tube..  

This is why having a 2 burner or 2 tube affair with their own fuel circuits would make it the easiest..  But  adding a secondary air injector to sweep across the ribbon burner might work even if it is NA..  Then you would only need to increase the fuel as you would no longer be running pressurized  air in the NA tube section.. 

Next question is how do you slow down the velocity enough not to have dragons breath spewing out the sides in wasted heat..   

I have often thought about doing a heat recirculated unit and this would cut down on fuel consumption..  and if setup correctly would induce a natural draft.. 

[Frosty]

I developed the NARB because there was a basic flaw in the blown ribbons as described by John Emerling. There is NO good reason to need high static pressure to make one work. That was an indication there was too much fuel air mix being fed into the outlets. I made the NARB as much to prove the point as anything, then it turned out to be a better burner than I'd been using for decades.

A NA induction device is high volume low static pressure so I just increased the number of outlets to reduce the necessary static pressure till it balanced out. Too few and stops it from working at all, too many and it burns back into the plenum and doesn't work. When I set out to make the thing work I wasn't thinking about how much better the low flame velocity would be for efficiency. Looking back it's obvious the longer the flame stays in the forge the more energy it can transfer to the liner and work. it's a big DUH but wasn't on my mind at all. 

I'm figure this is session as an exercise in "Can we MAKE it work?"

Frosty The Lucky.

[Exo313]

What about birthday candles? I'm thinking about trying them; one would think they would melt out rather easily. They also come in a couple different diameters, which appeals to my desire to tinker...