A thin hotface medium/low mass beer keg (drum size) furnace for melting Iron

Discussion in 'Furnaces and their construction' started by PatJ, Aug 24, 2017.

  1. PatJ

    PatJ Silver

    I also saw a burner that was used on a WWII ship, and it had a small disk with spiraled grooves in it, and also large adjustable combustion vanes.


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  2. PatJ

    PatJ Silver

    I did not really want anything as complex as either of these two burners, but I did borrow a few ideas from each one.

    I originally considered using four mig tips in a pinwheel configuration, but that was getting too complex, and I wanted something that was all steel that would take a lot of heat without melting.

    I bought some stainless tubing the other day to use for making a rust-proof burner tube, and I used an online program to make templates for the cuttoffs/cutouts.
    The templates worked well, and the joint turned out quite tight.
    I welded the two pieces of pipe together using a nickel rod.

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    The inside of the pipe must be free from any burrs or obstructions so that the inner parts of the burner can slide into the burner tube.

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    I slit the end of the burner tube, heated it, and bent some vanes onto the end of it.

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    I made a piece to go in the center of the burner tube to hold the spin vanes, drilled a 0.5" hole through it, and streamlined both ends.
    I was going to use a steel brake line in the center, but it was not rigid enough to make a strong assembly, so I went with a 0.5" steel tube, and will use a steel brake line inside the 0.5" tube.

    I decided to make a simplified burner with similarities to the burner from the "Fire Assay" book, it use some type of cone at the end of the fuel tube that will distribute the fuel outward into the airstream.
    I made a cone with a 45 degree face, and cut six spiraled grooves into the sloping face with a Dremel and a cut-off disk.

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    I welded the cone to the vane support, with the point of the cone aligned with the through-hole in the vane support.
    I originally was going to leave perhaps an 1/8" gap between the end of the brake line and the cone, and then it occurred to me that it may divide the fuel flow better if the cone was actually touching the end of the brake line.
    The vane support will be fastened to the center tube with a setscrew.

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    I started making a paper template for the spin vanes what will go inside the burner tube and be attached to the vane support piece.
    Its a little tricky bending a curved piece like a vane in a piece of sheet metal.
    I may have to grind the outside diameter of the fins once I weld them in place.

    It would be nice to draw the vanes in 3D, and then somehow project them out on a flat surface, but I have no idea how to do that.

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    So far, there is nothing that will be permanently attached to the 0.5" tube, so should the vanes and cone arrangement not work, they can be removed, and Plan "B" can be installed.
    Don't ask me what Plan "B" is; I don't have one right now, so this better work.

    I tried to make the cone large enough to compress the air in the burner tube and increase the velocity where the air passes over the edges of the cone, with the intent being to get good mixing of the fuel and combustion air.

    If the cone diameter is too large, then there will not be sufficient combustion air flow, or the air will have such a high velocity that the flame will climb upwards along the back of the furnace at a nearly vertical angle.

    Hopefully I can get it assembled enough to test it tomorrow.
    If this works, I can finally kick the air compressor to the curb, but new ideas seldom work on the first try, so I am not going to count any chickens (or ducks) yet.

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    Last edited: Nov 18, 2018
    Tobho Mott likes this.

  3. That swirl chamber in the first photo looks interesting, I might try the shallow cone (second photo) on the exit side on my nozzle and see how it affects the spray cone pattern.
     
  4. PatJ

    PatJ Silver

    Those designs are quite interesting, and no doubt there are some useful features that could be borrowed from them.
     
  5. Your new prototype looks like it would work with high pressure fluid alone, as well as with airflow doing the atomization. It could be attached the garden hose to the 0.5" stainless tube with a hose clamp and give it a high pressure "water test". It looks like it'll have a serious flow rate even at low pressures.
     
  6. PatJ

    PatJ Silver

    Granted just using a drip tube that terminates at the end of the burner tube (like ironside's burner) is a simple way to do a drip-style oil burner, and it as ironsides video's show, his burner design works well.

    What I am looking to gain in this design is a drip-style burner that will start easily on diesel, and not need a propane preheat.
    I am also looking for a drip-style burner that atomizes better than the typical drip-style burner that is in common use now, with the idea that if it atomizes better, it will give a smoother burner that hopefully does not have any fluctuations in it, and also hopefully provides a more sensitivity/fine fuel adjustment.

    I am not sure if ironside's burner can start on diesel without a propane preheat, but I have seen him use a propane preheat.
    If I get good enough atomization, then this burner should start using diesel only.

    High pressure would not work with this configuration since the fuel flow would be too high.
    I am using the same 15 psi air pressure on the fuel tank, and the same flow rate, which is 3 gal/hr.
    I have not changed the fuel needle valve setting from my siphon nozzle setting.

    The idea is to be able to use either this drip-style burner or the siphon-nozzle burner in a plug-and-play fashion, without having to make any fuel flow or valving changes.

    I need to weld three stainless nuts on the burner tube, and use three screws to center the nozzle in the tube, and make the vanes, and an end cap, but could potentially try it out tomorrow if things don't get too busy.

    I am trying to keep things as modular as possible so that I can accommodate various types of nozzles/sprayers/vanes/cones etc. arrangements all in the same burner tube using the same 0.5" central tube.
    I think I could slide my existing siphon-nozzle interior into this burner tube if desired, but I will have to verify that, and will probably keep the siphon nozzle burner separate as a backup unit.

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    Last edited: Nov 18, 2018
  7. PatJ

    PatJ Silver

    I need some ideas on how to make the vanes that go inside the burner tube.
    I really don't have a good approach for making these.

    Anybody got any concepts on how to make these?
    I need some collective brainpower here.

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    Last edited: Nov 19, 2018
  8. Those ones you show as a cardboard template?. You could cut a series of thin sheet stainless washers and partially slot with a dremel and give each pie shaped segment a twist with pliers to the right blade pitch. A version with the blades attached on the outside rim may require extra slotting/holes to enable it to be twisted without resistance. Stacking multiple blades in alignment is possible but may not be necessary: thin blades work fine for turbines.


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  9. PatJ

    PatJ Silver

    This person seems to be doing what I want to do.
    I would use less pitch than this example, and I would use perhaps four or five blades, but you get it idea.

    So at 2:27 he projects the helix to a flat plane, and he gets a circle.
    So do I cut a circle in a piece of sheet metal? and when I stretch it out it fits the burner tube?
    Only one way to find out I guess and that is to cut one out and stretch it and see if it fits.

    I would guess that I can cut one out of card stock and try that first for a mock-up.



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  10. PatJ

    PatJ Silver

    Perhaps I am overthinking the length of the helix required, and maybe I just need some blades like are shown below, but I am going to try a multi-bladed helix if I can figure out how to fabricate it, and the reason is that I am trying to compress the airflow around the central 1.185" hub and increase its velocity so that the turbulence will give a good fuel/air mix.
    I feel like I may need more blades/turbulence because I don't have an atomizing nozzle to break up the fuel.

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  11. PatJ

    PatJ Silver

    I made a template on card stock using the inside diameter of the burner tube, and the outside diameter of the central hub, and the template is indeed a circular shape.
    This shape will spiral around the central point in a helix, but there are limits as too how long the helix can be stretched out until the template no longer fits the hub, and I think I need a steeper angle than what the template approach will provide.

    So I guess I will have to use the blade approach, or custom cut a template that will spiral around the hub at a high angle.

    I created the very rough spin-vane assembly for the first oil burner I made (photo below), but it is quite a crude affair hacked out of steel bar.
    I need vanes that are a little more refined than this example.

    I am guessing that a flat template for vanes at a steep angle would be more of an ellipsoidal shape.
    I guess I will draw an ellipse in CAD, print that out, and see if it spirals around the hub correctly.
    It may take some trial and error to get the right ellipse dimensions.
    I would guess that the minor axis dimensions would be equal to the O.D. of the hub and the I.D. of the burner tube.

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    Last edited: Nov 19, 2018
  12. PatJ

    PatJ Silver

    Here is some template work I just tried.
    Below is a circular template, and this shape can be stretched along a cylindrical shape as long as the angle of the helix is shallow.


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  13. PatJ

    PatJ Silver

    Here is an ellipsoidal template, with the major axis being a randomly selected 3" long, and the minor axis being equal to the I.D. of the burner tube and the O.D. of the hub.

    This is a much better fit when the angle of the helix is steep, especially when the last 3/8" or so of the template is trimmed off either side.

    I think this will work.
    The vanes will probably be welded onto the hub, so a precise fit is not required.
    I think the fit will be close, and the angle is about what I wanted to achieve.

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  14. PatJ

    PatJ Silver

    One question that I though of last night is will combustion begin inside the burner tube?
    This would be very bad if this happened, and would overheat the burner tube, or cause it to degrade badly over several melts.

    If the combustion does occur inside the burner tube, I will cut the fins off the end of the burner tube and let the ends of the spirals that are cut into the cone align with the end of the burner tube.
     
  15. You could achieve your helix by stacking several static sheet metal fan blades with spacer tubes in between, it wouldn't be a contiguous helix like you're after but the function should be the same. You could easily vary the helix pitch by adjusting each fan blade with needle nose pliers to try different settings.

    Regarding combustion in the tube: I do get combustion in the burner tube at the moment, I'd used 4" tube with the intention of lining it with 0.5-1" dense castable refractory but the tube doesn't get hot enough to discolour, the flames don't appear to contact the tube walls. Smaller diameter tube is going to be a different thing entirely, your new nozzle may act as a baffle and allow the flame front close to the nozzle.
     
  16. PatJ

    PatJ Silver

    I got the vanes and end cap made tonight.

    I started with a rough cardstock template, then refined the shape, cut a vane out of metal and bent it into a curved shape, refined it a bit more, made another card stock template from the refined metal vane, cut three more sheet metal vanes, discarded the first one, bent one to the shape needed, and bent the other two vanes to match the curve.

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    I tack welded the vanes onto the hub (the rods/welded just did not want to weld the thin sheet metal to the heavy hub, so the very sloppy tack welds; its times like this when you need a TIG).


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    Then I slowly ground the vanes down evenly until I had a light sliding fit into the burner tube.

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    And finally ground the welds off a bit and cleaned it up.


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    For a prototype it is good enough to use to check proof-of-concept.
    I think I am close to testing it.
    I believe I can temporary things together enough to perhaps try a test tomorrow, unless I overlooked something.
    If it doesn't work, I will use it as a paint mixer. :confused:
    It looks kind of exotic. If it doesn't work, I'll call it "art" and sell it for an absurd amount of money to someone foolish enough to buy it (trust me, those people are out there). ;)

    It has sort of a Buck Rogers spaceship look to it.
    For the newbies/spring chickens/johnny come latelys out there, the Buck Rogers TV show was the 50's version of Star Wars, and we watched it on one of those newfangled viewing boxes called a black and white television.
    The show was made in BC (before color).
    Now those were the days. :cool:
    Cars: No power brakes, no power steering, no air conditioning, AM radio, three-on-the-tree, steering wheel as big as a truck tire; but I digress into yesteryear, and we don't want to get off topic, lest we may never get back on again.

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    Last edited: Nov 20, 2018
  17. Peedee

    Peedee Silver

    Buck Rogers was the late 70's (As a young male I distinctly remember the female actors wore hot pants), but I agree, that does look very syfy. Look forward to the test.
     
  18. PatJ

    PatJ Silver

    From Wikipedia (referring to the black and white TV series):

    1950–1951 ABC television series
    The first version of Buck Rogers to appear on television debuted on ABC on April 15, 1950 and ran until January 30, 1951. There were a total of 36 black and white episodes in all (allowing for a 2-month summer hiatus).[1][24] Unfortunately, no episodes of the show survive today.

    I think there were later versions of the show also.
    I remember the outfits too, but they were quite tame (very tame) by today's standards (there are no standards today :D).

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  19. Peedee might be thinking of the Flash Gordon remake, the company I worked at had an accountant nicknamed "Ming the Merciless". To me it looks like a harpoon tip or some sort of armor penetrating projectile.
     
    Last edited: Nov 20, 2018
  20. PatJ

    PatJ Silver

    I remember Flash Gordon too, and I remember Ming very well.
    We watched a lot of westerns, sci-fi, army movies, and cartoons. I remember my parents had strict limits on our TV watching time, so we just walked to the nearest neighbors house that had a TV, and watched over there all day long (you do what it takes). And I remember one time my grandmother invited us over to her house to watch cartoons on Saturday morning on her big console COLOR TV.
    We had a B/W small TV, and I will never forget seeing cartoons for the first time in color; it was a sensory-shocking experience to say the least, and needless to say we were never happy with B/W again.

    If this burner does not work, I am going to try to get a patent for a drain pipe cleaning device.
    I think it has potential in the waste management business. :)
    I would call it the "Turbo-Blaster" or something like that. (Edit: Looks like there are a million trademarks with that name, I better come up with something unique. How about "Flash-Booster".) Edit02: That name is also taken. How about "Roto-burn". I don't think that name has been used. Edit03: Strike three, that name is out there. How about "Spiral-cone".
    Strike four: Here is is:
    https://www.amazon.com/NAVA-Stainless-Spiral-Atomization-Industrial/dp/B00MHNEJXW
    Ok, last try, how about the "Helix-Cone Oil Burner".

    Hopefully it will have potential in the oil burner world too.
    I am getting ready to try it out.
    Fingers crossed.
    I will try to get a video.

    Will it work?
    Place your bets now.
    My guess is that it has about a 25% chance of working correctly as configured.
    Prototype designs seldom work right out of the gate.

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    Last edited: Nov 20, 2018

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