Torch burning out in forge

[Venturi]

Hey I made a simple Ron reil type torch. It runs fine outside of my $350 furnace I just built but when inside it can only operate at lower psi. 

Upon observation I see the flame gradually leaving the torch nozzle then shooting back untill it shoots away one last time and goes out. I feel like this has to do with either my intake or exaughst. 

Can post pics of desired.

[Frozenforge]

A picture of the setup and a few more details, propane pressure, what type of regulator would be helpful.

[Venturi]

Burner is 1/8" brass tube for gas flow. It goes through a 1.5" × 3/4" bell reducer to a 12"×3/4" pipe and another 1.5inch reducer for the nozzle.

I drilled out a 1/16 inch hole for gas flow and not a #57   . this is most likley my problem. Perhaps the gas flow is too great and pushing away my flame in the forge? I would've bought a smaller bit but I'm so poor I owe the bank $...

thanks for the reply frozen.

forgot to mention I'm using a high pressure regulator from tractor supply. no real measurement of psi

[Frosty]

Welcome aboard. If you put your general location in the header you might be surprised how many live within visiting distance.

Download Ron's directions, pictures and all and FOLLOW them. You'll have a much better chance of success than just winging it. Just because there're flames coming out one end doesn't mean it's "running."

Seriously if you can't afford one lousy drill bit you certainly can't afford the craft.

Frosty The Lucky.

[Mikey98118]

Venturi,

It is hard to tell for sure from the photo,  but that looks like an armored cable covered gas hose leading to your burner; I heartily approve of that stuff used that way.

[Frosty]

Mike: Are we looking at an all primary zone torch? (More discussion and I'll have the terminology straight. I remember what you were saying just not the terms. It's a TBI, aphasia thing) After reading your posts about your burners, wave fronts, etc. and what's going on I'm thinking I may have stuck my foot in my mouth. . . again.

Frosty The Lucky.

[Mikey98118]

Frosty,

I see no stuck foot problem.

First, let's talk burner versus torch. Manufacturers and dealers usually call anything running out in the open air a torch, so I could get away with calling all my burners hand torches, since they are all tested for performance in the open air, and work well as hand torches. But they are all designed to be primarily used in heating equipment, so it is less confusing to call them burners, whether hand held, or installed.

Theoretically, we are talking about an all primary combustion zone torch/burner. However, the burners must be built correctly, and then carefully tuned to make that flame. Most readers can't resist "doing things their own way; just some 'minor' changes, you know?" Then too, an even larger percentage of readers don't follow directions about tuning the burners correctly, which begins with distance of the gas jet to the entrance of the mixing tube opening (; once that is done, the overhang on the flame nozzle is CRITICAL to burner performance, especially if the operator desires complete primary flame combustion.

Note: I called the elongated gas jets n my first book" accelerators" for good reason , but gas jet is the accepted term, and the difference they make is now accepted far and wide, so "gas jets" they are from now on.

If these two parameters are met. complete combustion from a neutral primary flame will result. In the real world this rarely happens, so I'm used to seeing a wisp of secondary flame most of the time. As a hot rodding mad scientist monomaniac, this disturbs me, but it makes no practical difference at all; especially when these burners are installed in heating equipment, because their flames actually change and improve inside a forge or furnace; you can see them elongate and their outline becomes smooth, instead of slightly jagged, as they appear in the open air.

I believe it is back-pressure from the equipment the burners are installed within that improves the flames, and although I had always assumed the refractory lining absorbing sound was the reason they ran so much quieter inside heating equipment, it just now occurs to me that the change in the flame is a more likely reason for this. Burner noise is created by turbulant flame; the smoother the flame the quieter it is. I never tumbled to that obvious conclusion before, because I hadn't experienced the drop in flame noise from Vortex burners, which make much smoother turbulent flames than my tube burners produce.

To explain my claim of quieter burners, we only have to remember that laminar flames, whether from air-fuel Bunsen burners, or from torches make so little noise that the sounds we associate with either tool are simply the sounds of gas flowing into the mixing tube(s); sounds which are normally drowned out by the flame noise from turbulent burner flames.

Don't you just love the obvious? Conclusions, floating around right under your nose can take years to be sniffed out; this one lay dormant for a decade and a half!

That should read oxy-fuel torches

I think most readers falsely assume that tuning is done with the sliding choke. What the choke is really for is cold start ups, when the flame nozzle isn't heated enough to assist with fuel combustion, and for running the burner rich at times, which otherwise couldn't be done with one of my burners.

[Frosty]

Torch or burner? A good place for a jargon term don't you think? something specific to our applications. Other wise being the junior etymologist I am Id point out a burner does nothing but burn something. Too general a term unless we've established the context. Torch, isn't that a kind of burner? Well, not the British (European?) flashlight kind of torch of course but anything from a hand held rush light to a Tiki torch to an oxy fuel torch to an oxygen lance?

A fun bit of something to argue about over after a couple single malts. However using the term torch for your burners seeing as they're designed to operate properly in open air I think that qualifies them as a member of the torch family of burners. Then again were I using one it'd be a torch outside an appliance and a burner when in one. That's me though.

I almost never just call a forge burner "Burner" till I've established the context: forge, melter, etc.

I guess in short so long as I know what a person's talking about they can call it what they like. . . within reason of course or I might call them.

When I mentioned the tertiary flame from Rex's burner the orange bits were only features of a tertiary flame. I can accept it's erosion of that grade stainless. The feathery transparent dark blue flame was however a tertiary flame.

I can go along with the hypothesis back pressure improves performance with these burners. I can't refute it without just flapping my gums and this is too enjoyable a series of conversations to mess up. Being contained in a chamber could well quieten them down as well but maybe not why you think. More in a bit.

I disagree about your hypotheses about burner noise, turbulence is rough not necessarily loud. A well tuned gas burner roars because it's a controlled explosion and where the sudden expansion of the gasses determines how loud and how the wave fronts are directed.

The T burner burns outside the burner all the expansion of combustion is uncontained except by the forge. You can hear one burner on my forge at the house apporx 100' away through the shop walls. Guys driving up the driveway have heard it when they make the turn call it 250' through the trees.

Loud is NOT a recommendation, it's wasted energy I'd really rather keep in the forge as heat.

Combustion with your burners is finished within an inch or two of the nozzle so all the explosively fast wave front is condensed in a small area has much less surface area to transfer energy to the air. It is also traveling straight ahead so most of the sonics are impacting the forge liner directly in front of the tube.

Okay, just reread your paragraph about laminar flames being quieter. I can't say ya or nay though I don't that's the case a Fisher or other tapered tube burner. The entire path down the tube from the throat to the nozzle is one long trailing edge turbulence and diminishing pressure zone. I always believed they were quiet because the air fuel mix was traveling so slowly.

I can certainly see why being contained would smooth your burner's flame seeing as it depends so heavily on a contained wave front. It's a logical assumption. Heck, mine burn wildly and they really benefit being enclosed.

Hmmmm. Most guys building gas burners tune them lean then choke to tune so that is indeed true for them. I fiddle with mine till it's burning how I want it without choking. The air fuel ratio curve is nearly flat it's close enough at any reasonable primary flow pressure.

What are you tuning by moving the nozzle sleeve (flare)? Mine burns fine cold not quite right but not off enough to adjust anything waiting for warm up.

Frosty The Lucky.

 

[Mikey98118]

Yes, varying the amount of overhang in straight-tube-and-spacer-ring burner nozzles has a huge effect on the flame, since, in effect, it is quite similar to changing the amount of taper in a flared nozzle.

As to your other comments, we is "going where angels fear to tread" now. Or to use a Star Trek term, you are now about to enter the Undiscovered Country, and your answers can only be found in a lot more research; at this point old Dr. Frankenburner is quite sensibly hiding under the table and waiting for some other victim to take on that challenge

Not all of my burners need choking at start up; some don't and others do. Since they are hand built, such differences aren't predictable, and since a choke must be installed to prevent overheating the burner from chimney affect, at shut down. I never tried to run that oddity down.

[Frosty]

 Lacking a better term right now I'll make this one up, "Telescoping tube extension?" Or?

My question was what does moving it do to tune the flame?

For instance, I know what moving the jet closer to or farther from the throat of the tube does and can describe it in detail.

Jer

[Mikey98118]

When you move this kind of flame nozzle outward, the flame softens, when you move it back toward the mixing tube edge you harden the flame; move it far enough forward and you not only get two flame envelopes but you can even soften the flame to reducing. Move it back far enough and you get a leaner and leaner oxygen rich flame, until it blows out completely. The effects on the flame are much stronger than the effects of gas jet spacing.  Consider nozzle overhang to be the crude setting and nozzle spacing to find the "sweet spot" a further refinement of that crude setting.