Reil/Wenig burner question

I built one pretty much copying Brian Booorman's design at

-Will

My experience is that tip size only determines mixture. If you have too large an orifice for your venturi, even with the choke fully open you'll never even get it neutral. (Mind this is affected by the flare, which adds a bit of back pressure. A short flare will burn much leaner than a proper one.) Too small an orifice and velocity will be slow because the intake will be so choked off with respect to the diameter of the burner tube.

A good flame is a short inner cone of blue color. Not a lazy green (or worse yet, yellow tip due to carbon burning) flame, which is too rich. A thin purple flame is lean, with a good burner you can push it very lean indeed without it blowing out. Others, particularly with bad flares or none at all, have a certain flame velocity and mixture limit: an open-end pipe can be used as a burner for very slow flames, and it can burn neutral. The low flame velocity is unstable and it might start fwooping. If it fwoops once too hard, the flame will kick up in the tube and burn near the intake (no good). At higher gas pressure, you have to reduce air flow (choke) to keep velocity down, otherwise the flame will blow off. So you add a flare, and suddenly this little pressure step at the end allows burning at very high velocities, even fully lean. The technical name is a flame holder, and if it's not holding the flame (at the shoulder formed between the end of the burner tube and the flare), you can know right there it's not burning right.

I suspect you could've done as well with the smaller tip, just at higher pressure and more choke. This boosts up the velocity, while giving more lean headroom (if you need an oxidizing atmosphere or extra flame temperature). It also reduces maximum power, as only so much propane is coming in.

Try. Typical sizes are #57 for a 1" pipe, .030 for 3/4", .022" for 1/2" conduit (no venturi needed), etc. I'd guess 1/16" for 1 1/2" pipe.

Bah, I've never made a proper flare in my life. I just bend some sheetmetal (24ga. works good) around a size smaller pipe then spring this on the burner tube. No taper, the step between inside of burner tube and flare (i.e., pipe thickness) holds the flame. (BTW, a perfectly smooth burner tube doesn't work. It needs the abrupt step.) I let it hang out about i.d. past the end. I'd never go with 2 x i.d., with a taper I suppose it might work but it's just too much hot sheetmetal. Wasteful of the heat and whatnot. However, anything shorter than i.d. will be unstable, burn extra lean, etc. Make sure it's easy to replace, it WILL turn to scale in half an hour, particularly if you're melting bronze or something.

Note: no flare is necessary if your furnace/forge's tuyere is a tight fit to the burner tube.

Tim

-- "I've got more trophies than Wayne Gretsky and the Pope combined!" - Homer Simpson Website @

Thanks for the thorough response. I had not picked up on the fact in my own reading that when properly working the flame actually burns inside the flare just off the "step" formed by the wall of the burner tube and the body of the flare. I (and a few others whose results I have been studying) have been trying to get the flame out of the burner tube and the flare.

Yeah, there are three modes of burning:

1. Back in the burner tube. It has a pulsating sound. Heats up the burner tube and generally burns bad.... no good.
2. After the shoulder, as mentioned. This is normal operation, and has a good loud burning sound.
3. After the flare. Mixture is too rich to burn at the shoulder, so burns at the first sight of more air, namely at the end of the flare.

You're welcome. :)

Tim

-- "I've got more trophies than Wayne Gretsky and the Pope combined!" - Homer Simpson Website @

I to have a through the large end of the reducer two holes for the gas line. Is the flame tip end flared ? This is important to keep it alive. Not to much, but an obvious flair helps. Once the furnace is hot the flame can't go out. While cold it can be tough.

Mart> I built one pretty much copying Brian Booorman's design at

Got it working. I settled on a Tweco drilled/reamed out to .063". This was the max size for a neutral flame at 25 psi with the choke fully open on my design. I made just a simple flare as you suggested - just a 2" length of slip-over SS pipe. The thing really roars and now wants all the air my choke can give it above 25 psi. It now runs consistently with control of the choke from a few psi all the way up to 35 psi. It does burn inside the flare now which gets red hot but the burner pipe stays cool. Next step is to ram the refractory in my completed furnace shell.

I've built several Reil burners, and find the following details useful:

Fuel gas is 1/8 inch pipe size, with a tee in the middle of the reducer bell. Both ends project through the bell; one end is capped and the other end connects to a 1/8 inch needle valve and then the supply hose. The nozzle is a 1/8 inch solid steel plug with a drilled orifice. Easy to change orifice sizes by switching plugs. Number 57-58-59 drill sizes seem to be ok for 1-1/2 inch pipe size - you can experiment until the flame looks good. Obviously, gas pressure affects this size. I find that 15 to 10 psi propane is ok for me. Dave .

Why 35psi.? I can melt cast iron with the Wenig Monster Burner using

Also note that open air testing is not a good indication of proper burner operation. I have seen burners that would not burn in open air do just fine in the furnace.

Ron Thompson On the Beautiful Florida Space Coast, right beside the Kennedy Space Center, USA

The ultimate result of shielding men from the effects of folly is to fill the world with fools.

--Herbert Spencer, English Philosopher (1820-1903)

And some furnaces don't burn right without the crucible in place. Ideally you should be capable of all three. :)

Tim

-- "I've got more trophies than Wayne Gretsky and the Pope combined!" - Homer Simpson Website @