chrisfrick Posted August 28, 2009 Share Posted August 28, 2009 Hi all, this is more a question for Frosty, being that I'm using his burner design for my first gasser (and I didn't even have to pump him for info! . My question is this: how far does the nozzle of the burner protrude into the forge? Should it be even with the inside refractory material, pulled out slightly, or just adjust the depth for best burn? BTW, the forge is being built out of a R134a refrigerant cylinder and it's going to have a single, 3/4" burner, insulated with kaowool/itc-100 (or equivalent). Quote Link to comment Share on other sites More sharing options...
Frosty Posted August 28, 2009 Share Posted August 28, 2009 I try not to poke the burner nozzle very far into the refractory. The farther into the forge it is the fster it burns up. I stabilize the Kaowool in the burner port by sopping it with Kaolin slip and then a coat of ITC-100 so it holds it's shape. If you aren't using a thread protector as a sacrificial nozzle improvised flare simply make a wood or cardboard 12:1 flare form and mold the kaolin wetted kaowool to it to make a burner flare. Hope this helps. Frosty Quote Link to comment Share on other sites More sharing options...
chrisfrick Posted August 28, 2009 Author Share Posted August 28, 2009 Okay, makes sense now. Thanks for the info, Frosty. I probably won't have all the materials together for about another month or so, but I'll definitely post pics when it's all done and runnin. Quote Link to comment Share on other sites More sharing options...
Frosty Posted August 29, 2009 Share Posted August 29, 2009 Glad to help. The flare ratio should've read 1:12 not the other way round. Basically around 12 degrees of taper. If you have any other questions just give a shout out. Looking forward to seeing another smokin HOT forge in action. Frosty Quote Link to comment Share on other sites More sharing options...
Charlotte Posted August 29, 2009 Share Posted August 29, 2009 One of the things that I've noticed on several of my forges is that, even when the metal of a burner is out side of the refactory and not touching, the reflected radiation from the forge at welding heat will eventually destroy the first half to one inch of the burner. Quote Link to comment Share on other sites More sharing options...
Frosty Posted August 30, 2009 Share Posted August 30, 2009 It sure will. I extend the life of the thread protectors I use for a sacrificial nozzle by dipping them in Kaolin slip. Frosty Quote Link to comment Share on other sites More sharing options...
John B Posted August 30, 2009 Share Posted August 30, 2009 Glad to help. The flare ratio should've read 1:12 not the other way round. Basically around 12 degrees of taper. If you have any other questions just give a shout out. Looking forward to seeing another smokin HOT forge in action. Frosty Hi Frosty, I am finally in possesion of most of the parts to make a "T" burner to your design, And just getting ready to try to make the burner flare, when i read the above quote. Can you clarify the 1:12 ratio please. I make that about a 5 degrees (4 deg 46 min 19 sec) inclusive, Where did the 12 Degrees come from ? or does it not really matter as there is quite a difference between the two dimensions Quote Link to comment Share on other sites More sharing options...
pkrankow Posted September 1, 2009 Share Posted September 1, 2009 (edited) I made some templates out of paper. I need to remake them when I get kaolin. They are funkier than you might think.ConeCalc or this onecardboard cone calculator Phil Edited September 1, 2009 by pkrankow added another link Quote Link to comment Share on other sites More sharing options...
Frosty Posted September 1, 2009 Share Posted September 1, 2009 A one in twelve ratio means that the diameter will double in twelve times it's length. For instance a 1" dia will taper up to 2" in 12". Or down to 1/2" in 6". When I set my lathe up to do it, it worked out to around 12* as close as I could see through my specs. I've heard 12* from others who make flares as well. I could be wrong I'm not good at math. Frosty Quote Link to comment Share on other sites More sharing options...
chrisfrick Posted September 1, 2009 Author Share Posted September 1, 2009 Okay, seems like I *might* have to pump Frosty for info after all. All this talk about the flare has confused me back to my original question--is the flare convergent (gets smaller at the end of the tube), or divergent (gets bigger at the end of the tube), is it on the actual burner tube, or built into either a mount on the forge, or part of the inside of the forge? Closeup pictures would help a great deal. Quote Link to comment Share on other sites More sharing options...
Frosty Posted September 2, 2009 Share Posted September 2, 2009 The flare is divergent at the end of the tube. Here's some basic info as to what a flare is, does and why in the hope it helps more than it hurts. There are gas burners with nozzles (convergent) ends intended to direct the flame in a long narrow jet. These are commonly used in arrays like an air curtain in large open furnaces to help contain the heat. We don't want this type burner but they're out there so don't be confused if you see one. And yes the same ratio applies just like a fire hose nozzle. The 1:12 ratio is the maximum rate you can expand or contract a tube and not induce turbulence in the fluid flow. (moving gas behaving like a fluid in this instance) Inducing random turbulence in an inducer hurts induction. These burners are adaptations of standard induction devices. The 1:12 ratio does a number of things but these two are the most important in our application. Most significantly, as the flame expands to fill the flare the vacuum increases in the tube behind it and induction of intake air is improved. Next, as the flame expands to fill the flare it slows down because there's more volume to fill. This helps keep the flame from jumping off the end of the burner. It also helps disperse it in the forge so it isn't a long cone impacting the far wall but an expanding fan at best or a short blunt cone as the norm. Taking as a gross fact that increasing the cross section of the burner tube in increments that don't induce too much turbulence is good for performance there are a number of things that will help, if not as much as a nice smooth 1:12 flare for the full length of the burner tube from throat to tip. The most popular half measure is the short tapered flare on the end. Next is making an approximation of a taper by stepping up the diameter in small increments. A thread protector screwed on the end is exactly that. Another is using the forge refractory liner as a step increase or better yet a tapered flare. I hope that didn't muddy the waters more than it helped. Frosty Quote Link to comment Share on other sites More sharing options...
chrisfrick Posted September 2, 2009 Author Share Posted September 2, 2009 Thanks TONS, Frosty--now I get it completely. Just waiting on some insulating materials, ITC-100 and some time to go do some welding/forging to make a stand. I'll definitely get back with some pics and notes. -Chris Quote Link to comment Share on other sites More sharing options...
Frosty Posted September 12, 2009 Share Posted September 12, 2009 Thanks TONS, Frosty--now I get it completely. Just waiting on some insulating materials, ITC-100 and some time to go do some welding/forging to make a stand. I'll definitely get back with some pics and notes. -Chris My pleasure Chris. I'll be looking forward to seeing pics of that bad boy in action. Frosty (who's gotten seriously behind checking posts) Quote Link to comment Share on other sites More sharing options...
tribal forge Posted September 13, 2009 Share Posted September 13, 2009 Frosty Think you can help me make a small gas burner for a gasser!/Selden Quote Link to comment Share on other sites More sharing options...
Frosty Posted September 14, 2009 Share Posted September 14, 2009 Frosty Think you can help me make a small gas burner for a gasser!/Selden You know I will Seldon! Frosty Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.