The best of the best burners!

Discussion in 'Burners and their construction' started by OMM, Jun 8, 2019.

  1. oldironfarmer

    oldironfarmer Silver Banner Member

    Like probably most everyone I've wanted an Ursutz burner. Trying to do that in the bottom of a furnace with a corbel or orifice plate has me wanting to build another furnace. When I first started on foundry work I read where several people claimed you always want to build a better furnace. I didn't understand it then but I do now.:eek::rolleyes:

    I believe an internal disc would approach flame temperature and be subject to failure. Refractory hot face with a cold side keeps sucking heat out of the hot face and thus cools it allowing it to survive. The disc internally to the furnace would have little cooling and would suffer much higher temperatures. Maybe someone will try it.
     
  2. OMM

    OMM Copper

    Black diamonds.
     
    Jason likes this.
  3. OMM

    OMM Copper

    I’m getting a little bit off topic, but I designed it after one of those rubber hose clamps stretched open. I’ve been in the trades too long. For many years as a Cyl, surface grinder. Industrial black diamonds have always been my go to for shaping thousands and thousands of grinding wheels. In one of the pictures there is about $100 of dust on that cardboard.
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  4. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    How much head room do you have above your crucible? Most folks have cylindrical furnace walls but you may have to make it fit your IFB wall segments more closely. Simple enough to cast a dense refractory disc 3/4"-1" thick with holes whatever/however you want and sit it on an IFB pedestal in the center. If you don't like it or it breaks, just remove it. An annular chamber with a 3"x3" square cross section maybe?

    You could leave it unsupported around the perimeter or if you were that concerned about it just loosely install a short thin soldier course of IFB around the perimeter of the furnace floor so the OD was also supported. If you cured it sensibly, it may still crack but not fall apart. My thought was as much for natural gas fired burner and flame distribution system. An oil burner may have some additional considerations. I'd imagine you could cast it in a morning's work if you set your mind to it. I think you-da man for the job!

    Best,
    Kelly
     
  5. oldironfarmer

    oldironfarmer Silver Banner Member

    Not sure, Kelly. I think I'd need to replace all my brick with 3,000F brick before doing a high temperature modification low in the furnace.

    My crucible is sitting on two half firebricks right now. I've got a couple of inches from the top of the crucible to the bottom of the arch, maybe 2-1/2. Not sure my burner tube is low enough.

    One issue with the disc with holes is voiding in case of flameout. With a brick corbel you still have the entire ring open, even if the opening is a narrow ring.

    Thinking about an Ursutz burner, I'm guessing something like 10 square inches of opening would be plenty. that would be a groove about 3/8" wide on a 10" diameter circle. Pretty narrow opening and would take a refractory disc on the plinth anyway.

    I just don't believe even 3,500F refractory would hold up to that service.

    Only one way to find out, I guess.
     
  6. PatJ

    PatJ Silver Banner Member

    I tried an oil-fired preheater just to see what sort of temperatures I could get, and I could not get very much delta T.
    I think 600 F is as hot as I could get, and I think you would need a large volume of air at least at 1,000 F.

     
  7. PatJ

    PatJ Silver Banner Member

    Here is the Urstuz patent.
    Did I post this already?

    Notice that it is made from refractory, not steel.
    Steel Ursutz's don't last any time at all.

    URSUTZ-BURNER.png
     
  8. oldironfarmer

    oldironfarmer Silver Banner Member

    Preheaters are used in industry to save fuel, but 600F is 20% of the way to 2,500F from 100F. So that's nothing to sneeze at. A lot of the engery to heat air is the humidity in the air. That can make a big difference in furnace temperature if you are burner limited.

    The best preheater cools the exhaust to heat the combustion air. A furnace with a stack just needs a double wall stack and draw the combustion air between the walls.
     
  9. OMM

    OMM Copper

    My 15,000lbs cast iron foundry that I frequent (and I just stop by yesterday to pick up a a couple pieces) I asked what they use in their furnace for fuel. His reply was coke. They use exhaust air and re-circulate it. But they also have scrubbers... to keep the emissions down. I’m not sure if this was mandated on him.

    They fire up the furnace every morning at 8 AM. Every day they start pouring at 2 PM. 5 PM graveyard shift comes in to clean up.
     
  10. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    You recently did an iron melt. What furnace did you use to do that?

    If you don't have the space that's a problem. Thought with your previous comments about the benefits of big fire boxes maybe suggested otherwise.

    I can't see why an array of holes of similar area around the disc would be any more or less a problem in this regard than a ring but I wasn't necessarily advocating for any particularly geometry thus my previous whatever remark.....holes, ring/slot, interrupted ring/slot, -whatever.

    Although I suspect there is benefit, I think achieving the kind of heat that exceeds the service temp of the 3500F (or even less) refractory is probably a bit optimistic because even if the atmosphere is approaching theoretical flame temp (doubtful), the refractory isn't.......and even if so, a good problem to have as opposed to not enough heat/energy potential....just dial it back. The whole premise is to shift any cool zones and promote more complete combustion and temperature rise before the region of the furnace where the crucible resides. If you have enough heat to melt iron and upper regions of the furnace wall and lid survive, why would simply moving that region to a lower point in the furnace pose a problem?

    Best,
    Kelly
     
  11. oldironfarmer

    oldironfarmer Silver Banner Member

    Interesting subject.

    Same furnace, I only have the one.
    I think I have the space.
    My burner is pointed downward, the bottom of my crucible is the hottest part of my furnace. I get mostly a 360 degree swirl before the flame rises.

    Wall brick is cooled by heat flow outward, even when it is well insulated, there is still heat loss. A ring with holes in it will not have as good cooling. The Ursutz burner melts crucibles because trapping the flame in a closed chamber lets it approach combustion temperatures. I believe if we put a chamber at the bottom of a furnace with gas outlets into the furnace we'll get a similar response. I'm a little worried about plinth failure too and have been thinking about plinth cooling. I feel better about a corbel surviving than anything which is fully within the chamber/furnace. Even with propane it is possible to get the temperature high.

    As I've said before the short heating cycle of a home melt prevents the refractory from fully coming up to temperature. A 24 hour melt would be much more severe on any furnace even with the same inputs. You have a good point, I keep thinking about long term operation and that just doe not happen.

    The iron melts are hard on my 2,600F refractory. I see the loose brick inside are fractured into about halfway up. They haven't fallen over but are surely close to the end of their life. But the iron melts around 2,300F. Capturing the flame before injection into the furnace will result in a high temperature area.

    My interest has not waned. I melted my 10 lbs of iron (tiny, I know) in about 45 minutes from a cold start.
     
  12. OMM

    OMM Copper

    I noticed a few guys using the Delavan siphon nozzle.

    Does anybody know which one is the favourite for a diesel and the favourite for motor oil?
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  13. PatJ

    PatJ Silver Banner Member

    I think most people use the 30609-11 (that is what I use).
    Although it is rated for a nonimal 1 gal/hr, that rating is derived from a 5 psi compressed air flow.

    A Delavan siphon nozzle I think has a 3:1 or 4:1 ratio of usage, and so a 30609-11 can achieve good atomization up to 4 gal/hr, and I have actually pushed 10 gal/hr through one and still gotten pretty decent atomization.

    I run 30 psi compressed air through my siphon nozzle, and use 15 psi on the fuel tank.
    The fuel flow through my burner is controlled by a needle valve, and not controlled by the 30 psi air pressure.
    Some people reduce the compressed air pressure, and perhaps use it to control fuel flow.
    I prefer to have a good compressed air flow (to make sure I get full atomization of the fuel), and use a pressurized fuel tank, and control with a needle valve, and that allows me to never have to adjust the burner once it has been started and initially tweeked.

    I have never heard of anyone using either/or for motor oil or diesel.
    You definitely need an inline fuel filter as a minimum with clean diesel fuel, and perhaps a screw-on fuel or oil filter with used motor oil, depending on how clean/dirty the oil is.
    If the used motor oil is relatively clean and free from solid materials, an inline fuel filter may also work, but I would probably go with a screw-on filter with waste oil.

    .
     
  14. OMM

    OMM Copper

    Thanks pat.
    I found three of these today for $7 ea. They were made and assembled for something. Needle valve, solenoid...
    But they are 30609-2.

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  15. Melterskelter

    Melterskelter Silver Banner Member

    I am using a .75 size and pressurize my diesel fuel to 8 pounds using a simple 12V automotive fuel pump. By pressurizing the supplied fuel it is easy to push 2.75 to 3 gal per hour through the nozzle. Atomization with compressed air is especially useful for starting the furnace as you need not first preheat using propane as you would with a common drip burner that does not atomize. However, once the furnace is hot you can use it basically as a drip burner by turning the compressed air way down from around 8-10 PSI at startup to probably zero (I am to try that with the next burn) and certainly 2 or 3 pounds which I have done. If you do not pressurize the fuel, the siphon nozzle won't siphon on zero air and will suck only 1 gallon or so per hour on 5 to 8 pounds atomizing air. Given the simplicity of a propane and oil drip burner, I think they deserve a close look. I will stay with my siphon as it is all set up and is convenient. But, if I were starting from scratch and knew then what I know now, I probably would go drip.

    As you can see from many recent posts, the position of the burner relative to the position of the crucible may play a very significant role in melt efficiency. This factor also was not evident to me on my first furnace build and not as clear as now on my second. Living and learning.

    Denis
     
  16. oldironfarmer

    oldironfarmer Silver Banner Member

    I have a 30609-11 I bought but never used because I built the drip while waiting on the spray nozzle.

    But you have the most expensive part, the 17147 nozzle adapter. The tip is about $12 and the adapter about $30. You can screw a larger nozzle into your adapter.

    And that looks like you have a needle valve on the inlet to your solenoid, very cool.
     
    Last edited: Jun 14, 2019
  17. OMM

    OMM Copper

    It also looks like it can be easily drilled out. The SNA.20 Number I think might be metric for the size of the orifice diameter. I just put a wire pin gauge and it reads 0.009”

    This is just a guess, but for 11 orifice size might be 0.040“
     
    Last edited: Jun 14, 2019
  18. oldironfarmer

    oldironfarmer Silver Banner Member

    Maybe, but I think it is a more complex part than that. Maybe not, you have nothing to lose.
     
  19. Petee716

    Petee716 Silver Banner Member

    The orafice in the acorn itself (orafice disk in Delevans drawing) might be a different size too. I use the 30609-11. Ill verify the sizes if I can find my wire guage unless OIF has his handy. Handy Andy.
    I didn't realize it at first but the nozzle actually comes apart into 2 pieces which would be helpful in drilling the 2 different diameters if you choose to.
    I start my furnace on deisel till its hot and then change fuel hoses at the burner and burn waste oil. I just hang my Deisel bucket up and run about 15 psi and let the air and gravity pull the fuel. I run my blower at pretty low speed with a router speed controller at that point. That will melt aluminum itself. When I switch to oil I run 20psi in the tank and about the same 20psi atomizing air. Once I'm well established on oil I open the needle valve up on the fuel and increase my air till I'm satisfied with the burn. It's a WAG really.
    During mid-melt last weekend I turned the compressed air off as Melterskelter is suggesting and went from a nice flame 3 inches out of the lid to a black sooty roaring orange flame about a foot high instantly. It was actually a little startling. I wasn't in a position to start fiddling with pressures and flows at that particular moment so I just turned the atomizing air back on and admired the black coating all over the furnace lid and melt surface. It is definitely worth revisiting though

    Pete
     
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  20. Melterskelter

    Melterskelter Silver Banner Member

    Pete,
    Next time sneak up on it. If you got sooty, that means you were very reducing, right? So maybe you needed to replace all that compressed air (20 PSI is a Lot More than I run—-not sayin it’s wrong, mind you) by running up your combustion air considerably. Perhaps go down to ten PSI and rebalance, then 5, 2, 0 rebalancing each time. I do not know that will work, but seems somewhat logical. If you’d get a big sooty flame, at least coat your skimmer so the iron doesn’t stick. ;-)

    Denis
     
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