HI all, I know I'm a new member and this is an old thread but mostly I hope I'm not going to stir up a hornet's nest.
Ed: I assume you're using the same blown ribbon burner plans by John Emerling, published by ABANA and currently on Wayne Coe's web site. Or a version. yes? How many feet of dragon's breath is blowing out the ends of your forge?
Fuel burning OUTSIDE the forge is not only wasted money but is dangerous as putting your head in the oven. CO poisoning is cumulative and takes something like 80 times as long to flush from your blood as it takes to build.
I looked at the plans on Wayne's site and there are a couple basic design flaws that make it both inefficient and ineffective. There is no reason to put the diffusion plate to close to the air fuel inlet in the plenum. As called for in the plans it REQUIRES a blower with high static pressure to work at all.
The fuel air mix that gets to the plenum is moving at really high velocity meaning you have to pump a LOT OF FUEL through it to keep the flame from blowing off the outlet nozzles.
I've seen numerous videos posted by guys bragging about how hot their ribbon burner forges get and they do get hot. A few actually brag about the 3-4 FEET of flame blowing out the openings!
A ribbon burner is only one shape of multiple outlet burner and I won't change the term for purposes of discussion. They are common everywhere, from your gas range to glass artist's glory hole furnaces. They are everywhere and they are mostly "Naturally Aspirated" (NA) That means no blower supplying air. Commonly called "venturi" burners.
I put together NARB (Naturally Aspirated Ribbon Burner) to see if I was right and it was successful far beyond my expectations. I experimented with wood burner blocks, I only needed to watch test blocks burn for a few seconds to read the flame, wood lasted about 15 seconds before burning wood completely distorts the flame making it unreadable for propane flame properties. Make sense?
Prototyping in wood showed me that putting the intake directly above and inline with the outlets naturally made the center flames much larger and the outer ones burn back into the plenum for lack of velocity.
I mounted the inlet in the side of the plenum and eliminated the problem in any significant sense. The center flames are a little larger but not enough to make a difference. I don't do perfect, I'm a blacksmith and tinkerer.
I found the right number of crayon size outlets to balance the fuel air flow without requiring silly high pressure. What surprised me is how much better a T burner works screwed into a ribbon burner.
I use a thread protector on my T burners as a step flare rather than put a flare on them, I get thread protectors from the corner plumbing supply by the bucket to take them off their hands. I used one of my trusty hole saws to make the port in the plenum and welded a thread protector to it. I just screw a T burner on and light it up.
Testing the thing I discovered it is stable from stop to stop on my old 0-20psi regulator. The problem running silly low psi is there isn't enough flow through the nozzles to keep the burner block from reaching ignition temp of the fuel air mix causing it to burn back into the plenum. I've also run it to max psi on a 0-30 psi regulator and it maintains a smooth stable flame but holy moly!
If any of you wonder about my bonafides, I know my poop. I've been making NA burners for probably 30-35 years. If you've heard of the "Frosty T" burner. It's my burner, I'm that Frosty.
I hope I'm not breaking a rule but I'm just going to post the threads I started on Iforgeiron. The first one is about NARB and how I developed it. The second is a pair of NARBs in my latest too large propane forge. My next one will be very different but NARB fired. We can talk about forges too if you'd like.
Frosty.
https://www.iforgeiron.com/topic/480...r-photo-heavy/
https://www.iforgeiron.com/topic/48314-narb-lives/