Burner Tuning

[JosephPrivott]

Well, it happened. I finally got my act together and built a gas forge!

The Lowes hardware in town being what it is (certain words not fit for this forum), I was not able to find the appropriate parts for a burner, so I had to improvise. the basic idea is a Reil type.

I've got a 10psi reg on the 20lb tank, but am blind tuning it since I have no guage. I'll fix this as soon as I can. In the meantime, I've got a #60 orifice on the nipple, but am not seeing very good function in the forge itself. the parts are as follows:

1.25" to .5" reduction coupling
.5" x 8" Nipple
1/8" nipple with #60 orifice

I've not got a flare on it right now, but need to make one. I assume the flare should sit just behind some of the refractory (i've got insulating wool in a 6" chamber)

I tried a Zoeller style burner, but as is the case in both, they seem to benefit with the addition of even blowing in the tube. I planned on adding a blown system, but the atmospheric should work. What gives? I'll cut the burner body down if I have to, somebody let me know

Thanks

[ThomasPowers]

What kind of function are you seeing?

[JosephPrivott]

without using a blower from a vaccum, it appears to be a rich flame, I see yellows when the reg is cranked open. anywhere from that point to "off" is just a weaker burn, no oomph. when I blow in it, it's appearant it's starved or something

[NateDJ]

With out the flare the burner will not function properly. The flare allows the fuel to burn just at the end of the burner and not inside the burner. This allows the heat to be created where you need it as well as allowing for a more complete burn of the gas. The flare creates a low pressure point which draws the air fuel mixture down the pipe. It will be critical to your air supply.

[Frosty]

Joseph:

You're ratios are WAY off.

A .5" burner tube needs to be 4" + 1/4" - 0" long. The intake flare should be a .75" x .5" bell reducer and the jet would be something on the order of a #75-80 bit. I'm taking an educated guess at the jet dia as I experiment rather than trying to do the math. I'm not very good at math.

There is NO WAY yours will burn cleanly as it is. If tunable it's appropriate to heat a volume of about 175 cu/id.

I'd advise building one as per Ron's instructions and dimensions if you like a linear type burner. Or build an ejector type using the Sidearm, Porter or my "T" configurations. One word about my "T" configurations, I'm not having a lot of luck scaling the things down from 1" to 3/4", I'm getting a lot of variation from tube to tube and am having some real head scratching moments tuning them.

If you want a .5" burner Rex Price builds them that small and they work. Otherwise you'll need to experiment till you get one working. I'll be happy to help as I can.

Frosty

[JosephPrivott]

@Nate: sweet, I figured as much, jst didn't have the time at the moment. something about the zeal of burning something...

@Frosty: awesome. I'll implement your notes immediately. I may not have an 80 bit, but I've got something smaller than 60, so I'll use it for right now. i'll also trim the nipple down to 4.25" (that is the measurement you said right?)

[Frosty]

Between 4 and 4 1/4 is the ratio for length to dia of the tube Yes.

You'll probably want a smaller feed line to the jet as well as 1/8" will block a lot of the intake and may induce asymmetrical turbulence along with restrictions. Linear type burners don't like restrictions.

Frosty

[JosephPrivott]

http://www.youtube.com/watch?v=dgbKHOUk7dI

Well, here's an update.

The gasser works now. i'm seeing a little oxidation, and may need to increase my reducing tee's size to accomidate more airflow. I got a flare and welded it onto the burner. If it wears out I'll just replace the whole affair and redo it more precisely, now that I know what needs to be done.

Cost:
10" of 6" pipe- $26
8" black iron nipple
1.25" to .5" reducing coupling
4" 1/8" brass nipple
1/8 brass cap
1/8 brass female-female coupling
(all above sans pipe- ~$15)
insulating wool- $8

misc other expenses for drill bits- $10-15

[Frosty]

Where are you seeing the oxidization, in the forge or when you take it out?

If it's scaling up when you take it out, that's normal, if it's doing it in the forge then you want to either restrict the air intake or increase the gas jet dia.

If you're using it indoors then a little scaling is preferable to excess CO production. To eliminate oxidization for welding simply toss a piece of charcoal into the forge to absorb excess oxy.

Looking pretty good she is.

Well done.

Frosty

[JosephPrivott]

Thanks a lot Frosty, I also cut the tube down to 4.5" and used a #77 but for the nipple like you recommended. Your knowledge was invaluable for this, and it would not have come together as it did without you