GuillaumeMarchand Posted July 16, 2023 Author Share Posted July 16, 2023 In fact, I already have the probe. And in the process of making the enclosure of the forge, I'll provide a hole with tee correct diameter. I might not make the hole in the insulation but I'll be ready if needed. The IR thermometer pointing the anvil is a good idea. I'll keep that in mind Quote Link to comment Share on other sites More sharing options...
GuillaumeMarchand Posted October 28, 2023 Author Share Posted October 28, 2023 Hi guys, A quick update: it's alive! This is the first fire as I just received the 3D printer nozzles. I'll give you some data next week after a few tests. But it works. Here with one burner, 6psi, 0.6mm injector 1/2'' burner and 15 minutes since ignition, it's around 1900°F Thank you all for your help. I'll keep you in touch with the further steps. Quote Link to comment Share on other sites More sharing options...
timgunn1962 Posted October 28, 2023 Share Posted October 28, 2023 Just a heads-up about the TM902C pyrometers. I had a batch of ten of them a few years ago that seemed "off". I have access to a calibrator at work. All ten behaved the same. Read correctly up to about 800 degC, but then started deviating as the temperature increased. I can't remember if they read high or low, but either they read 1370 degC at 1290 degC or vice versa. I'd had maybe a dozen or so TM902Cs before that, bought in ones and twos, which had all been boringly accurate over the full range when put on the calibrator. I've not bought any since. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted October 28, 2023 Share Posted October 28, 2023 Hi, Guillaume Love to see your use of sheet metal in forge construction. I just advice guys to use old gas cylinders, tin cans, and pots. But that is only because, sheet metal is very expensive for an American who doesn't live near a scrap yard, so learning how to use sheet metal isn't an inviting prospect these days. As to the photo showing the air entrances and gas tube on your burner. One of the earliest improvements made on burners, was to square up the forward and rear ends of slot shaped air openings. The second improvement was to bevel the forward and rear edges of those openings; both changes greatly increase air induction into tube burners. The result is way hotter burner flames. The thicker the tube wall the more important beveling is... Your gas tube looks way too long. While some tube length is needed to increase the speed of gas molecules leaving the gas orifice, how long that needs to be depends on orifice size; the smaller the gas orifice the shorter the gas tube needed. Also the smaller the inside diameter of the gas tube the smaller the tube can be. However, there is a "sweet spot" where the gas orifice is at the best distance away from the forward end of the air entrances to induce maximum air into the burner. I estimate that to be about 3/16" on that burner size. Are you employing a .3mm 3D printer nozzle as a gas orifice, or some other size? Quote Link to comment Share on other sites More sharing options...
GuillaumeMarchand Posted October 30, 2023 Author Share Posted October 30, 2023 On 10/28/2023 at 5:16 PM, timgunn1962 said: Just a heads-up about the TM902C pyrometers. I had a batch of ten of them a few years ago that seemed "off". I have access to a calibrator at work. All ten behaved the same. Read correctly up to about 800 degC, but then started deviating as the temperature increased. I can't remember if they read high or low, but either they read 1370 degC at 1290 degC or vice versa. I'd had maybe a dozen or so TM902Cs before that, bought in ones and twos, which had all been boringly accurate over the full range when put on the calibrator. I've not bought any since. That's interesting... As said before i'm color blind and don't easily trust what color I see in the forge, but during my second test, while the pyrometer said 1200°C, according to the color chart we all know, I would have said more like 1000°C. It seems that I shouldn't trust it. Thanks Quote Link to comment Share on other sites More sharing options...
GuillaumeMarchand Posted October 30, 2023 Author Share Posted October 30, 2023 On 10/28/2023 at 8:58 PM, Mikey98118 said: Hi, Guillaume Love to see your use of sheet metal in forge construction. I just advice guys to use old gas cylinders, tin cans, and pots. But that is only because, sheet metal is very expensive for an American who doesn't live near a scrap yard, so learning how to use sheet metal isn't an inviting prospect these days. You know, for a French it's very expensive too. I had the opportunity to gather scrap material over the years in my different jobs, and that's the amazing thing, all that crap append to match perfectly with this project. But yeah, buying all that stainless sheets and tubes would have be too expensive for me too. On 10/28/2023 at 8:58 PM, Mikey98118 said: As to the photo showing the air entrances and gas tube on your burner. One of the earliest improvements made on burners, was to square up the forward and rear ends of slot shaped air openings. The second improvement was to bevel the forward and rear edges of those openings; both changes greatly increase air induction into tube burners. The result is way hotter burner flames. The thicker the tube wall the more important beveling is... One of the guys on our french forum told me about that already, and I'm pretty sure he got it from you here. For now it seems to me that my burners swallows to much air because I had to reduce the air entrance as you may see on the pictures. On 10/28/2023 at 8:58 PM, Mikey98118 said: gas tube looks way too long. While some tube length is needed to increase the speed of gas molecules leaving the gas orifice, how long that needs to be depends on orifice size; the smaller the gas orifice the shorter the gas tube needed. Also the smaller the inside diameter of the gas tube the smaller the tube can be. However, there is a "sweet spot" where the gas orifice is at the best distance away from the forward end of the air entrances to induce maximum air into the burner. I estimate that to be about 3/16" on that burner size. Not knowing what length would fit, I started with the "10 times the diameter in length" ratio. So as the internal diameter of the tube is 15.9mm (5/8") I cut 160mm of tube. Regarding the position of the gas orifice you are correct, it's around 5mm. On 10/28/2023 at 8:58 PM, Mikey98118 said: Are you employing a .3mm 3D printer nozzle as a gas orifice, or some other size? I've tried 0.4, 0.5, 0.6 mm outside of the forge. In the forge the 0.6 seemed to work the best. Now, the guys here says that if I have to reduce the air intake it's because there is not enough gas and that I should try a larger injector diameter. For example 0.8mm, and open the air, resulting in a more powerfull but more balanced burner. Now you are talking of a 0.3mm injector and I'm lost. Anyway, I've received a bunch of 3D printer nozzle form 0.2 to 1mm if I remember well so it's no harm to try a smaller injector. Quote Link to comment Share on other sites More sharing options...
Mikey98118 Posted October 30, 2023 Share Posted October 30, 2023 Do not feel lost,Guillaume. Your friends have the right idea, but "the devil is in the details." I don't want to devil you, so I will admit that I got one of those details wrong; that would be the size of your burner. So, just ignore my question, and wrestle with less pesky details. If you're happy with the burner, than so am I Quote Link to comment Share on other sites More sharing options...
Frosty Posted October 30, 2023 Share Posted October 30, 2023 I have a couple suggestions to improve your burner's air fuel ratio. The farther back the jet is from the ends of the air ports the more air it will induce. Seeing as your jet hardware is a sliding sleave that adjustment looks really easy. Move it in SMALL increments at a time, Move, fire it up and observe, make notes and repeat if necessary. The length to ID ratio I learned from the brochures and paperwork I was gifted so many years ago says. Tube length should be 8x the ID, You can extend to to 9x the ID but it's not really much better and longer starts to degrade performance. 10x ID is over the line of reduced performance. Those should get you into fine tuning range. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
GuillaumeMarchand Posted October 30, 2023 Author Share Posted October 30, 2023 Ok thank you guys again for your help. I'll play with air and injector next time. I'll let you know the results Quote Link to comment Share on other sites More sharing options...
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