We have been on You Tube looking at the rotating blow through and reverbertory furnaces melting scrap iron in India . It appears most are using oil as you see the tanks being preheated. I have used crucibles with LP furnaces for years and have a lot of experience with that but we are pouring Iron molds large enough to need multiple crucible furnaces and having enough coordinated help is a big problem. In the old books I see a lot of talk of sweet crude but waste oil is everywhere and it appears hot enough to do the trick. I just have not figured out exactly what those guys in India are doing for a burner as I don't see a pump but maybe the elevated tank makes it work once a gas flame gets it hot enough to support combustion? Yesterday, I bumped into Windy Hill Foundry's very impressive Reverberatory furnace converted from a gear ladle that would pour 400lbs of iron and that would be more than we would ever need. I can see the fuel line in the back ground and it appears to go into the fan like the Campbell Housefield tilting furnaces back in the 30s but I really can't get a good look. From the fuel line I am suspeciouse it is propane? I would appreciate any thoughts on a burner either propane or used oil for a large direct contact furnace for melting scrap cast. I have went through every thread on here and while there are some amazing designs, most are for furnaces a little different than what I want to build. Thank you very much
Welcome. Might be helpful to post a link or two to the furnaces/burners you are looking at. Seems like there would be more to master in that furnace design rather than the oil burner. Can't say that I've seen any posts here or at the old AA forum on reverb iron for hobby casters.......most all crucible and Cupola. How much lbs are you looking to melt? It's not iron but Art's (Master53Yoda) bulk scrapper may be similar......propane start, switches to oil. https://forums.thehomefoundry.org/index.php?threads/building-new-furnace.3073/#post-55696 If you search Furnace or burner by Master53Yoda there will be threads with a lot of burner design and commentary. Here is his YT channel https://www.youtube.com/channel/UCOn4Bp7FC-n5yHvsXfd_yZg Best, Kelly
Clarke (Windy Hill) is never going to show how his burners work on YouTube. He told me he intentionally avoids it because someone burned themselves years ago trying to imitate his previous crucible furnace oil burner setup without really knowing what they were doing. He doesn't want to be responsible for someone else injuring themselves. Most of us here who use waste oil burners either use a siphon based atomizing nozzle (either a commercially available nozzle or a diy copy of same aka 'Kwiky' burner), or a drip injector type burner, potentially gravity fed (ie. "elevated tank makes it work once a gas flame gets it hot enough to support combustion" just as you mentioned. My waste oil burners work this way). The nozzles require compressed air to run the siphon; the drip burners, a preheated furnace (or external firebox). Check out some of the build threads here for more info. You might find some decent oil burner build videos on YouTube as well. In addition to @master53yoda 's furnace, I believe @Petee716 also has a reverb-like oil fired tilting furnace as well. Good luck! Jeff
My furnace uses 2 siphon nozzle burners with a pressurized tank oil delivery system, oil preheat to 160F, Currently I am manually firing the burners, I'm in the process of going to a Arduino menu driven burner control system. The oil burner is inside of a propane burner about 20kbtu that provides cold start. after about 5 minutes I can shut off the propane. My system has minimal Burner safety controls as the intent is continuous monitoring by the operator. If your furnace wont have someone attending at all times (cold Fire to Shut down) the large burners must have functional safety controls because the possibility is there for a major fire. One of my last resort measures is that all fuel sources are exterior of the Container that holds the foundry. worst case scenario, I can shut the doors on the Container and isolate the fire and fuel source. My furnace fires at about 6 gallons per hour waste oil, on high fire, that is based on 200lb aluminum load. I would think yours will fire higher then that. I will take pictures of the burner so there isn't any miss-understanding. The questions asked by AL203 would be necessary for a starting point Art B
Thank you for all the answers. I have been researching your replies like crazy. I really, really, like that design Windy Hill Foundry has and its obviously diesel with a large elecric motor running some kind of pump below the tank. I assume its an oil pump or maybe a hydraulic pump as it is a pretty big electric motor running it. He never gives a good view of the burner system but it is a shockingly small fan and looks like a 110 chord. I have used the Delevan burner tips with diesel and air but never got as hot of results as propane, I am wondering if pumping diesel with a high pressure pump would improve that? On something you are moving around from a chain hoist on a track, I would much rather use diesel or waste oil than LP. I am attaching some photos of the ones I was talking about on Youtube. The big blow through one is in India and a pretty high volume, the one on the ground is some art group and they were putting complete brake rotors in and melting so I was pretty impressed. I am really only needing a couple hundred pounds or a bit more on occasion. The fellow from Windy Hill says his tilting hanging furnaces pours pure iron as all the impurities catch on the back wall when tilted. I find that very attractive along with not needing those expensive crucibles. Thanks again to all that answered.
here are pictures of my furnace system, bear in mind that it is insulated for aluminum not iron. 1.5" wool with ceramic coating. The insulation system for Iron would need to be substantially heaver and have a hard castable for Iron scrap. My furnace size wise would handle about 175lbs aluminum in iron it would hold about 500 lb. It wouldn't be structurally capable of that weight. It also would need to reduce the volume of the scrap about 50% to provide sufficient volume for the oil to combust in the presence of the iron. So if we are looking at 250 lbs iron and a 1 hour melt time you would need approx 1.92 Mill BTU or about 13 gallons per hour of waste oil. This number is based on the formula below. Once the melt is complete the burners would need to cut back to about 2 gallons per hour for maintenance of the pool temp. Art B Total energy: (0.110 Btu/lb°F * (2800-70)°F) + 117.9 Btu + (0.146 Btu/lb°F * 100°F) ≈ 430 Btu/lb (approx.). Heat the metal needs to absorb. The last pic is firing at about 5 gallons per hour.
Master53yoda, I saw your Youtube vedeos and that is an amazing set up for what you are doing! I am looking into your burner suggestions real close. Thanks
Do you know if Pat Jorgensen is still around. I have been trying to find him but none of my emails are being answered. He has forgotten more about Iron refectories then I know. Iron insulation would be something we would need to discuss for a tilting furnace like mine. The bottom of my furnace is 1" wool ridgidized with sodium silicate. The top coat is 1" of sand, sodium silicate, ceramic slip,and stainless needles used in boiler linings for crack prevention. This handles up to about 2200F without breaking down. it also handles the abuse from loading full sized engine parts etc. But would not survive Iron temps. I haven't any experience with Iron temp refractories. Art B
In my crucible furnaces I always liked to use fire brick in everything but the lid, it doesn't last forever but my ramable refrectory never seemed to last as long, even the expensive stuff. There doesn't seem to be many people using the Ursutz burners but it sure looks like a few of those blow through furnaces in India are using them. Some mysterious cylinder with an oil tube and blower going in and impressive fire coming out into the furnace anyway. Some of them just look like hot oil drip systems from a gravity tank but still are impressive. Thanks
Clark's/Windy Hill Tilt is sort of a hybrid Cupola reverb, so you have to be willing to rebuild the expendable base for every pour like a Cupola. It is a practical solution to molten iron contact and trade against the cost of a large crucible which is of course expendable too after a number of pours. That's why I was asking what refractory you intended to use, because though there are many that can take the temp, though tolerating molten iron contact, residual slag and the general aftermath of the melt puts it in a separate class. I don't think he elaborated on the refractory he used for the reusable upper half, but was concerned about the cracking. This is a pretty classic problem with cylindrical furnaces. There was a former member here that went through a number of iterations of liner for his iron duty crucible furnace. The best result for him was making sections from phos-bonded plastic refractory. He used Blu-Ram but that's just one product/brand of same. Instead of fighting the inevitable cracking, he accepted it and the segments served as stress relief for the thermal growth/contraction. He used a well-tuned diesel burner because he didn't want to fight the inconsistencies of managing WMO or WVO. You can search the site here for Ursutz. There is some discussion. The NOBOX7 vids below and his others on YT contain more of the same. One other advantage of the reverb verses crucible furnace is you don't have to completely open the furnace to extract the crucible, which induces some rather large thermal shock which is hard on refractory. Segmental Thin Plastic Refractory/Wool Furnace Build 14" Dia Bore | The Home Foundry You might also have a look at NOBOX7's videos like the one below for some ideas. Reverberatory Tilting Hearth furnace built for Blake NOBOX7 weird furnace designs | The Home Foundry I think you'll end up burning a lot more fuel than your estimate because a furnace that size will likely have 100s of lbs of refractory that will need to be heated as well.....at least on the first heat, which may be all that is possible depending upon furnace design. Best, Kelly
My understanding if the Ursutz burner is that t they are vaporization chamber fire box. The fuel is only vaporized and raised in temp enough for ignition, the actual combustion happens outside of the burner. They would need sufficient combustion air supplied for combustion inside the furnace. Their physical size is designed to vaporize and ignite a given maximum amount of fuel, if that Maxim amount is exceeded they will flood and start pooling oil in the bottom of the chamber. They should turn down fuel rate well until they can't maintain combustion. That said they should work well enough as long as the are big enough to handle the amount of fuel that is being feed. Art B
Perhaps it's a misapplication of the term, but every example I have seen labeled as such actually has combustion as well. Might be a band aid for raising the temp in furnaces with insufficient combustion volume, but external combustion burners certainly will do that in those cases, and there's little chance of pooling fuel, at least once they are at operating temp. Best, Kelly
I think maybe i didn't describe the process correctly, The fuel does burn inside the chamber but the fuel burned is probably less then 10% of the BTU available the other 90 % is combusting in the furnace where it has room for combustion, The Ursutz burner would probably eliminate the need for the extra volume in the furnace needed for oil combustion as compared to a Gas fuel, as the oil is a vapor and has already absorbed the vaporization heat in the Ursutz burner. Thanks for bringing up any mistakes I make in my Descriptions. I looked at the video that NOBOX7 has The design of the refractory answers most of the Questions i was having. I would definitely use some kind of powered tilt on that furnace as I feel that the leverage bar method of tilting leaves to many chances for something to happen, also I'm 72 yers old and that is to much work. Art B
When I brought up the possible pooling in the Burner was because the calculated amount of fuel being feed was 13 gallons per hour. If the combustion in the burner doesn't generate enough heat in the burner volume to vaporize that much fuel, it would pool. Most of the Ursutz burners that i have seen are not vaporizing any where near that amount of fuel. Just my 2 cents worth( Maybe now a nickle due to no more Pennies beak made) Art B
That wasn't my intent, just making sure we were talking about the same thing. It's been a while since I looked at NOBOX7's videos. There are plenty of others out there on YT, but he does have some interesting and some very high-power burners, and many have combustion occurring within the burner. Many of those burners are metallic and operating at very high temperatures, which I'm sure would reduce them in fairly short order, but they could be made out of a refractory material. One thing that does confuse me is in some of his videos he suggests low flame temp for WMO and WVO, like only 2100F, which seems quite low to me. There was one I was looking for that was nautilus shaped, and IIRC, the fella claimed there was reverb within the burner itself.....couldnt find that one but it was very compact. I just bring this up for the OP since he expressed interest in oil burners and reverb furnaces. Some of these external burners have some potential advantages because you can easily contain pressurized combustion (more easily than in a foundry furnace), minimize heat loss, and raise the temperature of the air fuel considerably before entering the furnace, which may provide some additional leeway in furnace design. Best, Kelly
providing preheat on the combustion air definitionally would reduce the needed volume in the furnace, especially if your running lean fuel mixture. Which will typically generate a cooler flame temp. I have seen flames run 800 to 1000F cooler because of excess air on improperly tuned large boilers.. When I hear about the inability to melt iron or brass I think excess air is probably the underlying cause of not hot enough flame even when the fuel flow should be high enough to do the job. Art B.
