Robert's Black Iron Pipe Burner

[lbas]

Robert,

(Referring to original your post) Nice looking burner, nice pic with the parts callout. Hope you'll post again after you've run it on a forge a few hours and can give us some figures and observations on that. I for one am interested.

Best,
lbas (life begins at sixty)

[kcrucible]

I saw Reil's design actually. It is based off a cross tube for the gas which is drilled to create a gas jet as a small pinhole in the tube. Furthermore it has a flat design where air flows straight through the tube rather than from the sides. I considered that but saw a couple of design problems.

First of all there is no way to adjust forward and backward jet placement in the tube. Once the holes are drilled then the jet is positioned and there is pretty much no going back. This prevents tuning the flame and certainly prevents the use of MIG tips as a jet because the jet would be too far in the bell reducer. My jet tip ends right about at the end of the nipple and it looks like I need to back it off a bit. Short of redrilling a new tube location, that cant be done with the Reil.

He has other designs that eliminate these problems and is functionally the same as yours, though without the expanded air intake chamber, just using slots in the tube wall (originally just a hole, but the text on the site describes the slot as an improvement, though there are no drawings indicating that.) Your design theoretically can draw in more air than his mongo series because of the larger intake area, but I suspect that your jet doesn't provide enough suction to require it in which case it'd be a little over-engineered. What pressure are you using? On the positive side, if you ever wanted more heat you could probably just swap out the 3/4" tube for a 1" tube (since you have the bushing anyway) and upgrade the tip for more fuel. Nice and flexible.

I built one based on the mongo principles but haven't had a chance to fire it up yet as I'm waiting for my regulator. My link also has embedded images to the original Reil burner and the Mini-Mongo. Kcrucible's Propane Burner


Anyone want to give me any feedback prior to firing this bad-boy up?


Yes, I know that forward/back adjustment will be difficult and consist of heating the solder to push the ejector in/out, but I believe that the placement should be ok as-is. Just blowing into the brass nipple (low PSI) with the choke fully open causes more air to exit than when I blow in when it's choked down, so I think the venturi is working properly. Edited August 1, 2010 by kcrucible

[maddog]

I like to try out my own designs and ignore accepted wisdom too. It can be fun, though the results are often disappointing. I do it anyway. I learn alot from my failures.

I don't mean to criticize, disparage, put down or talk down to anyone in any way when I say that, in this case, the current designs in atmospheric burners among the smithing community represent a wealth of valuable knowledge. Burner technology is crucial to smiths and they have thought about them a lot. Bear in mind that the smithing community is a cross section of society. Among those involved have been numerous engineers and at least one professional combustion engineer.

As far as I know there are basically four atmospheric designs currently in use. I rank them in order of performance with the best first.

Hybrid Trex
Michael Porter's jet ejector.
Zoeller Side Burner
Ron Reils Aussie burner.

I haven't tried the Trex. You have to buy it. I dont know if it outperforms Porter's design. From reports, it sounds like it. But I've made a lot of atmospheric burners, some my very own design which performed poorly, and I have made the other three.

Rons burner was the first serious attempt to come up with a high performance atmospheric burner and yes, it has the draw backs that Richard mentioned. The side arm is a big improvement, easy to build with mostly off the shelf parts.

I have just finished up a 3/4" Porter type burner and its a beast! But it takes at least a day to make, more if you haven't made one previously.

I've done a fair amount of research reading technical papers on burner technology and AFAIK, no one has analyzed or modeled small atmospheric burners of the type we use. Its too much work. It's only done for big industrial applications where serious money is involved.

However, there is now a body of well tested empirical knowledge and as Thomas says, real data trumps everything else. Burner design remains something of a black art but over time a number of dependable design rules have emerged. I thought I would list these in a later post. It might be useful to us to have the information in one place where it can be easily found. I would be very grateful if people would add their knowledge or correct what I have written.

[kcrucible]

I haven't tried the Trex. You have to buy it. I dont know if it outperforms Porter's design. From reports, it sounds like it. But I've made a lot of atmospheric burners, some my very own design which performed poorly, and I have made the other three.

Rons burner was the first serious attempt to come up with a high performance atmospheric burner and yes, it has the draw backs that Richard mentioned. The side arm is a big improvement, easy to build with mostly off the shelf parts.

I have just finished up a 3/4" Porter type burner and its a beast! But it takes at least a day to make, more if you haven't made one previously.

As far as I know, the Trex is basically just a pre-fabricated Porter burner. They worked in collaboration.

http://www.hybridburners.com/new-vertouri.html

The burners now available of the Venturi design, both to build yourself and to buy through HybridBurners, are light-years ahead of those available a few years ago. Over the past two years Mike Porter in Seattle, Rex, and I, have put in hundreds or perhaps even thousands of hours in design and testing to develop the full potential of Venturi burners. I was the least involved because I was critically ill for almost a year of that time, but kept connected with them via the Net. These burners now run very hot, much hotter than Damascus welding requires, and have a range from a cigarette lighter flame to a small jet engine, and they are instantly tunable across the full pressure range for an oxidizing/neutral/reducing flame by a slight adjustment of the choke. They are simple, clean, and independent of external power requirements of any kind.

The Trex is machined to precise specifications, so it probably gets a minor boost from accuracy in construction and repeatability/tweaking that most people won't be likely to get into off-the-shelf plumbing parts. That's not to say that you CAN'T do it, it's that it would take a great deal of effort for the small incremental improvement. As one example, the ratio between welding tip orifice and burner tube diameter... when we're dealing with a static pipe dimension we choose the closest orifice that we can find to get the width that balances proper mixing with maximizing velocity. Since the Trex machines its own tube, he can pick an orifice and construct a burner tube to optimize for it.



Michael Porter's jet ejector and the Trex are basically a refinement of the Ron Reil's Mongo. Scaled down, larger air intakes, etc. Ron mentions many of the adjustments that you can make to the Mongo in text, that Michael Porter impliments in his book. Ron deserves a huge amount of credit for initial concepts, which the other guys then refined and developed into an excellent technology.


Someone sent me a link to what is supposedly an engineering schematic of a version of the Porter design, in case anyone has CNC equipment, etc. Scroll down and click the prov burner link.

http://kcrucible.wordpress.com/gallery-of-fire/

[maddog]

kcrucible,

Ive looked at some of your stuff online and see you have been seriously interested in burner design for some time. For my primary forge, I prefer to use a blown system. It's a lot less fussy and gives you more options. But the atmospheric burners are very useful and way cool. They are also very useful as a general purpose heating torch in the shop. My gf wants a Raku Kiln so I thought I would start making a couple. Those will probably be sidearm design with off the shelf parts.

I wasnt aware that Porter was involved in the Trex design. Looking at the Trex, I see the air slots have round ends, which Porter is quite adamantly opposed to in his book, claiming that this induces turbulence. I am going to have to buy a Trex soon. After the time I spent making a Porter design, the price seems very reasonable

As one example, the ratio between welding tip orifice and burner tube diameter... when we're dealing with a static pipe dimension we choose the closest orifice that we can find to get the width that balances proper mixing with maximizing velocity. Since the Trex machines its own tube, he can pick an orifice and construct a burner tube to optimize for it.

Yeah thats my problem right now. In open air, the Porter burner needs a jet between 030 and 035. (I am at 7000'). The back pressure from a forge might make the 030 a good match, otherwise I will try to enlarge an 030 with a tip cleaning file.

Thank you for the drawing of the Trex. It will be very useful

[kcrucible]

I wasnt aware that Porter was involved in the Trex design. Looking at the Trex, I see the air slots have round ends, which Porter is quite adamantly opposed to in his book, claiming that this induces turbulence. I am going to have to buy a Trex soon. After the time I spent making a Porter design, the price seems very reasonable

I agree it's not that unreasonable given the amount of work it takes to approximate. It comes down to time vs money really.

I had rounded slot ends on my burner when I was having trouble. As one of many simultaneous changes (more intake area, tapered inward on the inlet cuts, and I made it squared off at the same time) the problem was reduced with the square end. I was having burnback issues, so I could see the behaviour of the air/flame at the end of the slot. Porter is right in that things were a LOT rougher with the rounded edges. If I wasn't having burnback that doesn't neccessarily mean that it would have caused any problem though... I think slower velocity but better mixing. It could be that Trex uses the better mixing to generate a shorter tube and makes up for the velocity loss in other ways.

Yeah thats my problem right now. In open air, the Porter burner needs a jet between 030 and 035. (I am at 7000'). The back pressure from a forge might make the 030 a good match, otherwise I will try to enlarge an 030 with a tip cleaning file.

Thank you for the drawing of the Trex. It will be very useful

I'm using the 045 with a 1" burner. That thing screams.... or more accurately, whistles. Haven't fired it up inside the forge yet... I should finally have time tomorrow!


I'm glad that you enjoyed my site. I enjoy the experimentation and trying to understand how it's all working, why it works, how it might be improved, etc. While I don't ave access to CNC equipment, I figured someone else may get some use from the engineering drawing. Apparently the original was linked here from some user's site and it's never online.