Can a Zoller type burner be increased in size with good results? That is, I'm thinking of building a larger burner with say, a 1-1/4'' pipe instead of the 3/4'' or would there be problems?

Lookup "Mongo Burner" and Ron Reil.   Also if really interested:

Gas Burners for Forges, Furnaces & kilns written by Michael Porter.

 

Should give you all the information you need.   More than one way to skin a cat.

 

-Bruno

Not sure about Zoeller's but I upped Frosty's "T" style from 3/4" to 1" and it works great. Seems like the difference in intake shouldn't be much of a factor. The important thing is the diameter to length ratio. I don't remeber what it is off hand but I'm pretty sure Frosty has it.

Well, I took the 3/4" design and scaled it down to 1/2" for a smaller Zoeller style burner - I love it!

 

I have a plan on building a larger than 3/4" Zoeller-style burner (I call it a Wye burner) when I have a larger forge.

So, it would seem I could go up or down in scale but the length of burner tube may need to be adjusted in order to tune the flame....anyone disagree with that?................Thanks all......... B)

IIRC, what is important is a 9:1 length to diameter ratio; needs to be long enough to allow complete mixing of the fuel/air.

That sounds real familiar, John, and if memory serves, my 1" burner is 9" long. I'll try to remember to measure tomorrow and update. I do remember reading somewhere that it can be too long also. Something about friction coefficient reducing the efficiency of the natural aspiration. In a nut shell; Too long and you'll need a blower to force it down the pipe ;)

Assuming these burners use the same orifice, like .035 I guess one with a1/2'' pipe would need even less pressure to operate than one with 3/4''.......

The reason for the larger upscaled burner is not for economy per say, they will be going in a big forge to create more BTU's than the smaller ones and I expect they will need more gas pressure. My 3/4'' units need 5 psi to make things start to happen right off and up to 15-20 psi when I want a real blast so I reckon a 1'' may need 7-8 psi at an idle........Would you say that is true Dodge?

change orifice size 

Keep the gas jet diameter in proportion to the pipe diameter and you should be OK.

 

If necessary, I use a drill in a pinvice to open up MIG tips to the desired size; it keeps the conical lead-in and maintains the discharge coefficient. A plain drilled hole without the lead-in will flow about 20% less gas than a mig tip.

 

Heat (BTU) output goes up with the area, not the diameter.

 

Adding a choke is a really good idea. The mixture adjustment gives control of the flame temperature. The gas pressure controls how much gas. The combination of the two controlls how hot your forge gets. Depending on the forge design, it can also control how much of the forge gets that hot.

Yes, the ratio is 9:1 of the inside diameter of the pipe to length.  I had mine too long and Frosty got me corrected, runs much hotter now.   So a 1.25 pipe would be 11.25 inchs long. 1.5 inch pipe 13.5 inches long.

Well, I decided not to go with 1 1/4'' pipe and went to 1'' with good results I think. Even with the smaller pipe I had to kick the orifice up to .050 and it still seems a little lean. I used a cast iron bell fitting (1''/1.25'')on the end and it helps to prevent flame out although mounting it will be a little more challinging. The blue flame cone gets up to 6'' long at 20 psi......

1" conduit connector (after you've pickled off the zinc) works well as a nozzle.

Well, I decided not to go with 1 1/4'' pipe and went to 1'' with good results I think. Even with the smaller pipe I had to kick the orifice up to .050 and it still seems a little lean. I used a cast iron bell fitting (1''/1.25'')on the end and it helps to prevent flame out although mounting it will be a little more challinging. The blue flame cone gets up to 6'' long at 20 psi......

 

Fit a choke to it and you'll be able to control the mixture/flame temperature all the way between whatever you've got and reducing/Heat-Treating.

Fit a choke to it and you'll be able to control the mixture/flame temperature all the way between whatever you've got and reducing/Heat-Treating.

 

I don't use much choke with a Wye burner (Z-burner) - but when I do I use a magnet and put it on the opening and slide across as necessary to block the air intake.

I use a magnet as well, I thought I was the only one doing that.