Burners 101

[Mikey98118]

Frosty,

A vortex feeding into a mixing tube will create that exact phenomenon I look forward to conversing about this with you tomorrow, but right now the brain has had enough.

[Frosty]

No Mike, your vortex makes a cyclonic flow in the tube it isn't what I'm calling a toroidal flow. If you've watched a smoke ring you've seen a toroidal flow. Now visualize it stretching in a tube so the jet is punching down the center but the return is on the skin of the tube.

I didn't have a very good view of what was happening but this is a FAIR description of what I saw with my experiments using smoke from the jet in a clear plastic tube back when.

It's a completely different flow from a vortex.

Frosty The Lucky.

[Mikey98118]

Okay,

But isn't it time for you to give readers your thoughts on the whys and hows of "T" burners, just to round off this thread? I consider your burner design to be an important resource, and therefor your thoughts about belong here, at least as much as the why-fores of my burner designs do.

After that, it's probably time to start a follow on thread on the "ins and outs" of forge design...

[Frosty]

The whys and hows of the T burner? Why? Because it works, How? pretty well? I'm not sure how to answer that Mike I think the main why is because I wanted to do some blacksmithing didn't want to burn wood or retort charcoal in the trailer court and good coal is pretty hard to come by. Not that coal would've been welcome in the trailer court either.

Charcoal briquettes work okay once you figure out how to work them but still not good. I started messing around with a gun burner and almost had a chip forge reinvented when one of my coffee shop buddies, Cruz, started giving me (the fabled papers) about induction devices. He was looking for ideas to file application patents and I've always been good at brainstorming so Cruz started giving me more and more stuff. He was wanting to make a device you could fill a car tire with using a small high pressure source through an inducer like a jet ejector he'd picked up for filling balloons.

Reading the pamphlets and related materials I got a handle on inducers. About that time the internet went public and I met Ron Reil. I already had a linear similar to Ron's way more developed design. a 3/4" x 2"  Bell reducer on a 3/4" x 6" nipple with a strip welded across the center. Having a lathe available the center was hollow threaded for the fuel hose on the top end and drilled for the gas jet on the other. the outside is threaded for the aluminum choke plate.

It works pretty darned well but boy what a PITA to make. Works isn't a typo it's still out in the shop. The second generation was even more of a PITA to make, I attached the threaded jet fitting choke plate part with an external mount it worked better but still a major PITA to make and I have pretty high level shop skills and a lathe. Ron was talking about trying to make reliable burners in only a day of labor as a goal. Anyone who's looked knows what his earlier burners are like, lots of fiddly hand work but they don't need a lathe and are good burners.

Reading all Cruz's papers over and over AND having access to the internet and patent servers it dawned on me "Jet Ejector" type induction devices are considerably more powerful inducers. A well made linear inducer has an induction ratio of upwards of 1:20 For every unit, call it cubic foot of primary fluid, propane in our application it will induce 20 cubic feet of air.

Propane has a nominal stoichiometric combustion ratio of 1:17.5 it wants 17.5 parts air for every part propane for a neutral burn and a linear inducer will exceed this ratio. Either detune the inducer or put a choke plate on it. Cool that's plenty of cushion to let a guy make one out of plumbing parts in his garage.

Reading further about Jet ejectors I find they induce around 1:27 holy mackerel that's a HUGE fudge factor and I started tinkering. I tried a number of things and made working burners. I finally settled on the plumbing T fitting as the easiest one to repurpose. The run openings were well balanced and at a clean 90* to the jet. My first functional T burner used 1/2" lamp rod and a cludge of fittings to attach the mig contact tip and propane hose. But it worked a treat was easy to tune and had me melting steel in the forge if I wasn't careful.

I think that about sums up your question Mike. Why is because I really wanted to blacksmith. The how is luck on my part, a friend laid the right info on me at the right time. Maybe more significantly I'm kind of lazy and a linear burner is just too much work.

It works well because it's a jet ejector, the T supplies combustion air from each side in an even balance for a smooth flow. A jet ejector can induce up to 27x the primary flow so it's even easier to achieve a neutral fuel air ratio. I just kept increasing the jet size till I got a flame I liked. The slower the primary fluid velocity the lower the induction ratio. Increase the diameter of a nozzle it will pass more fluid at the same psi. I increased the jet dia till the increase in fuel volume and decrease in velocity balanced where I wanted, just a bit rich so my steel doesn't scale in the forge.

I don't know if that answers your questions Mike, to my mind the only real significance to the T burner is it's ease in construction, basic tools and minimal shop skills is all it takes. We didn't invent anything you know, these things have been around for a long LONG time. Falling water was used to pump air into mines. Water falls were redirected into vertical shafts which supplied high pressure high volume air into mines where the air supply was used to pump water out. IIRC that trick was used by Rome and it wasn't new then. inducers were used in gas lights, ovens and stoves in what the 18th. century? 19th. for sure.

These things been around an awful long time I just adapted one to be easy to make and work with minimal fuss.

Frosty The Lucky.

[Mikey98118]

I just used hunches on every new burner I designed; it was only afterward that I figured out the whys and where-fores about them. I never knew that jet-ejectors had such a high induction value compared to linear burners: I just didn't like that big reducer sticking out the end of my forge, and figured I didn't need it because of other changes I'd made to the burner 
Nevertheless, there have been surprising parallels in our thought processes . Using MIG tips came naturally to me, because of the years I spent as a welder. Mixing tube lengths to diameters came straight out of Ron's burner pages, and worked out just a little better in my designs then 8:1 might have. As to the changes in flame nozzle shape; they were made necessary by higher mixture flows. I even thought about building a Vortex burner model in clear plastic, just as a  teaching tool; never did though.

Finally, all I need to do is look at one of the Chinese propane torches to see that I'm no part of a combustion engineer. Yet it is good for some of us to keep on studying this equipment, because all those clever engineers are muzzled by the penny anti limitations of out of control bean counters; kind of makes me smile to know that the Chinese are cursed with them too.

[Frosty]

I shared the commercial inducer ratios with Ron in the early days along with the flared tube. Ron is who misunderstood flaring the tube and just stuck a flared on the end.

It was pure luck Cruz dumped so much information on me or I'd still be muddling around trying to get something to work. Well, I still am I just have a good working model to fall back on when my next brainstorm turns out to be a stinkbug. I have my fingers crossed, my latest experiments are looking promising.

Funny you should say that about the Chinese. The abacus is an ancient Arabic(?) computer but evidence shows it may have originated in China. They were invented to assist accounting. They're a simple frame with BEANS strung between them. The accountants who used them were called "Bean Counters" BECAUSE they counted the beans on their abacus'.

I'm pretty sure the Chinese just shared the curse with us.

Frosty The Lucky.

[Mikey98118]

Gas Tubes

I should have added that as the gas jets get smaller the gas tubes they get mounted on can become smaller too. My first gas tubes were cut down to 4" long from cutting one end off of schedule #40 1/8" pipe nipples. Larry Zoeller discovered that  schedule #80 1/8" pipe nipples could be threaded directly into, saving a lot of extra steps. Because the heavier nipples  were almost 25 percent smaller inside diameters, they had better gas flow, allowing these gas tubes to be reduced from 4" to 3" long will increasing flow performance.

Later on I discovered that some of the smaller burner's gas jets could run on as little as 1/16" tubing for gas tubes.

[Johan]

Hello guys, I am in the process of building a propane forge. It is a square style mini forge with one burner. I am having issues with the burner. It is a Ron reil ez burner design. I have copied the design to exact specs, the only thing I have not done is flare the sleeve but I'm under the assumption that it isn't necessary. I may be wrong let me know haha. So the problem I am having is that when the burner is pointing down the flame starts sputtering and sounds like it wants to come backwards up the pipe, but when it's sideways it works perfectly fine. Here is a picture of the burner let me know what you guys think. Thanks

[Buzzkill]

What pressure does this happen at?  If you're around 3 psi or lower when this happens it will probably go away by increasing the pressure.  If you're already at 5 psi or higher then it may be a design or alignment issue.   Also, it's best if you tune the burner where you will be using it.  If you try to tune in open air and then put it in the forge you will probably have to tune it again as things like back pressure are different in the forge environment.

[Latticino]

Cross-post with Buzzkill:

Frosty and Mike will probably have good suggestions for you, as they are vastly more familiar with the operation of propane NA burners.  I have  a couple of recommendations for you though:

1. Tune your burner operation inside the forge and make sure that the outlet is not too close to the opposite wall or floor and you have reasonable door openings (personally I don't like to put burners pointing down to avoid the chimney effect and side-fire, but YMMV)
2. You may want to play with the length of your mixing tube (downstream of your reducer fitting).  I think the typical rule of thumb is around 8 pipe diameters in length
3. Include a cast burner block in your forge to set the mixing tube against instead of the flare (12 degree angle of expansion is usually a good rule of thumb for that).

[Johan]

Hey guys thanks for your input, I'm not exactly sure what psi I'm running the burner at but if I turn it up too high it shuts off. My regular goes up to 20 psi I think it's full flow/high pressure. I'm unable to test it in the forge yet because I'm waiting on some blanket still, will probably get to it this weekend. I bought some brass parts today to hook up a water hose. I will check alignment when I get off work tonight. Do you think a #57 hole is too big? What is a cast burner block? I'm going to attach a picture of the forge itself for you guys, it's 9" x 12" the chamber will end up being 5x4x12 after the brick and blanket go in. What's the positive/negative of a side mount instead of top mount burner?

[ThomasPowers]

Hot gasses rise.  Any that get re-run through the burner will create a LOT more Carbon Monoxide!  Also Hot gasses rise so when you turn off the burner you then have the possibility for the chimney effect to be roasting the burner fittings that generally stay cool during use.

[Buzzkill]

If by "shuts off" you mean it blows the flame out that is something that may not happen inside the forge due to back pressure.  Tapering your flare (flaring the sleeve) will help with that issue outside the forge though, as will the cast burner block with a ratio of 1:12 or less expansion inside the forge.  The relationship of the gas inlet orifice compared to the inside diameter of the burner tube is important.  If you have followed the instructions for the burner strictly and those are the tube diameter and bit size specified then that shouldn't be a problem as that is a known burner design.  I haven't built one of those specific burners, so I'll defer to someone who has for advice on the orifice size.

A cast burner block is literally just a block of castable refractory that you can place in your forge where the burner enters it.  It would be surrounded by insulation on all sides and should end up pretty much flush with the interior surface of your forge.  It's basically provides a flare on the end of your burner tube and takes the place of a stainless or other flare. It helps with flame stability and if it is cast out of a quality refractory should not deteriorate due to heat as quickly as a steel flare would.  It's not required for the burner and forge to function, but it's a nice feature with some benefits if you make one.  The only down side to that is it's almost impossible to change the aim of your burner if it's effectively part of the forge's hot face.

Based on the dimensions you have you should only require a 3/4" diameter burner and that should be plenty for the forge. Side vs. top mount is a matter of preference.  As you show it in the picture when you turn off your burner heat will travel up your burner tube.  It doesn't look like you are using any really heat sensitive materials in your burner or the fuel delivery lines close to the forge, so you just have to remember not to touch it after you shut the forge down - or you can remove it immediately after you are done.  Some people aim the flame at the floor because the floor tends to be a more durable material for both mechanical and thermal damage compared to the rest of the interior so it can take more abuse from the more or less direct flame impingement.  For a side mounted burner, especially in a curved forge, you tend to get more flame swirl, which some argue provides a more even heat and more complete combustion in the chamber.  I'm not sure anyone has ever definitively proven that one is "better" than the other, since different factors are at play in each one.

[Frosty]

Johan: What is the long piece of large diameter tubing you have on the end of your burner? I haven't looked at Ron's EZ plans in a long time but I don't recall him calling for anything like that.

I need to know more about your burner to be of much help.

What is the pipe nipple's dia. and length?

Is there a flare, if so what are it's dimensions?

Unless you're going to make a torch for use in open air there is NO good reason to tune a burner except IN THE FORGE.

Aligning the burner horizontally has the advantage of minimizing the chimney effect when you turn the fire off and makes using rubber propane hose less dangerous. In a forge with the dimensions you give us mounting it horizontally neat the top would cause a strong vortex in the chamber evening out the temperature.

More details please, we'll get it up and running.

Frosty The Lucky.

[Johan]

Thanks buzzkill I'll have to look into the burner block design. Hey frosty, the piece of pipe on the end of the burner is the sleeve that's supposed to be forged into a 1/8' flare at the end, the design has been improved since then and was said to not "require" a flare as long as your not running the forge over 25+ psi. The length of the nipple underneath is 8" - the thread on one end so around 7 1/4". As of now the burner has no flare but it transfers from 3/4" to 1" inside diameter with the sleeve on the end. I ran some water through it yesterday and in order to have the water exit through the center at the bottom the jet hole was way off center at the top, could this be caused by a bur? The 1/8 brass nipple running through the reducer might not be perfectly square so I'll take the file to the holes tonight and try and get it as good as I can. If I mount the burner horizontally do I need a hard firebrick on the side wall or is blanket sufficient?

[Johan]

Had some luck playing around with the burner, turns out it was majorly out of alignment. I mounted it in my unfinished forge just to test out the burner in an enclosed environment and it seemed to work great. I decided to mount it through the top, If I don't like the way it works I'm going to try the side mount and plug the top hole. Check out this video and let me know what you think about the gas/air ratio. Thanks for all your help guys. 

 

https://m.youtube.com/watch?v=KfIMDMSE46I

 

[Frosty]

A 3/4" burner tube should be 6" long, 7" max. That long thing on the end is NOT improving anything it's actually making it less efficient. I use a thread protector instead of the burner "flare" made popular some years ago but it barely extends the tube 1" in length. I don't know what you mean by 1/8' flare. 1/8' is 1 1/2" (inches).  I assume it's a typo and you mean 1/8" (inch) flare and that's not right either. It should be a MAX 1:12 or 12% taper.

The music is very distracting the sound of your burner says as much or more than how it looks. Your burner is running VERY rich. Lose that extra piece of pipe, if that doesn't lean it down drill a smaller jet hole. No, I don't know what drill # to use, I use mig contact tips for gas jets in my burners.

You also REALLY need to rethink the fuel supply, all those fittings, nipples and loops of hose are inviting an accident. Hose is a trip hazard and long nipples between multiple fittings are weak points with a lot of leverage against them. Clean it up for safety's sake.

Frosty The Lucky.

[Mikey98118]

The burner can always be improved; the first improvement I ever made to a Riel burner was to replace the side hole in its cross pipe with a MIG contact tip, and all the other improvements followed from that. Each improvement not only improve performance, but also changes everything else about how the burner operates; they are a balancing act. I would suggest you look for the MIG tip change section of Ron's burner pages; you obviously have the tool skills to pull it off; choice a schedule 80 1/8" pipe to run the 1/4-28 MIG tip thread into, and upgrade to a 2" reducer from the 1-1/2" reducer you are now using (if that is a 3/4" size burner)

I'm more interested in watching the forge build than in critiquing the burner itself, and wouldn't mind seeing you move the video and future videos and text over to the Forges 101 thread.

BTW, I liked your choice in music

the text should read "improves" and ""choose.

Third dry; the text should read "improves" and "choose". Time for a break...

 

[Mikey98118]

What about buying a burner?

There are only a few companies that sell burner supplies, and even lest who sell good burners . Chili Forge makes the best naturally astirated burner, at this time and costs less than the next best. Next comes the Hybrid burner family; I personally don't like Price, but his burners are almost as good as a Chili burner, and comes in more sizes.

That was the "A" list; short, wasn't it? Larry Zoeller's "Z" burner didn't quite make it, but deserves honorable mention; this is a very nice running burner for a very low price, and almost makes the "A" list for performance.

The "B" list comes from Devil Forge; an eBay supplier; they are low priced for what they are (as long as you don't also buy one of their useless foreign regulators),  and they perform adequately.

Every other naturally aspirated burner I've seen for sale so far is IMHO JUNK.

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[Johan]

That's a lot to take in lol I thought it was burning great but I guess that shows I don't know much hence why I'm on here. I will shorten the 3/4" nipple, but the burner doesn't even run without that sleeve on the end, from what I understand it needs some kind of transfer in diameter to get a good draft or however you call it. I'm going to play around with the fittings once I have everything set up, when I know where I'm going to place the fuel supply and so on, it's all just Jerry rigged temporarily. I do take safety pretty seriously, that's actually why I'm building a gas forge in the first place. I'm going to take another video of the burner closer up and with no music and you can be the judge of how it sounds. I will look into buying a 2" to 3/4" reducer if it does need more airflow and maybe put in a smaller jet hole. I kind of want to run it in the finished forge first and see if it runs any differently, better/worse. I finally managed to get ahold of some blanket and rigidizer so I'll be doing a little bit of work on it tonight, I'll update you guys as I go along. Thanks Mikey, classical music really helps me work keeps me focused. 

[Frosty]

Where did you hear you needed that much diameter change? Hey, Jerry rigged?! I resemble that remark! Actually doesn't get better than that so . . . Okay.

Read back in this thread where Mike is talking about reading the burner flame. He doesn't call it that but the info is there. Pale opaque blue flame is rich, just a bit ore and it'll have yellow in it. It's feathery nature is another though less positive sign. Mike covers it much better.

Jerry The Rigger.

[ThomasPowers]

I thought it was Jack, Jack the Rip...

[Johan]

Hahaha. I think I may have found the reason it's running rich. I have a 1" to 3/4" reducer instead of a 1 1/2". Back to the hardware store I go

[Frosty]

9 hours ago, ThomasPowers said:

I thought it was Jack, Jack the Rip...

It was close to RIP Jack but it's RIP Birch instead.

3 hours ago, Johan said:

Hahaha. I think I may have found the reason it's running rich. I have a 1" to 3/4" reducer instead of a 1 1/2". Back to the hardware store I go

Heh, heh, heh, the guys at the local hardware or in my case the HVAC supply and service place up the road will end up knowing you by name.

Frosty The Lucky.

[Mikey98118]

I think you're right; you need the larger reducer. 1-1/2" is big enough for the original burner design. You only need to upgrade to a 2"x3/4"" reducer if you are going to replace the side hole in the cross pipe with a MIG contact tip in the cross pipe; if you go with that upgrade, be sure to move the cross pipe back us far as you can toward the large opening of the reducer fitting. 
 

Gentle hint; you get the MIG tip to thread into the new cramped quarters with flat pliers, or a drilled wooden peg, via the smaller opening it faces toward.