How oil burners work.

Discussion in 'Burners and their construction' started by Ironsides, Jun 11, 2019.

  1. Ironsides

    Ironsides Silver

    I watched this amazing video on youtube. If any beginner is thinking of building an oil burner they should watch this video. It shows that liquids do not burn but the vapours or gas given of that liquid. It also shows that the liquid fuel has to be prepared so it will burn. ( spray bottle ) This holds true using a light oil or a heavy oil like waste motor oil. I wish I knew this when I started making oil burners as the first ones were failures.

     
    _Jason likes this.
  2. oldironfarmer

    oldironfarmer Silver Banner Member

    Pretty cool video. Of course it's only the vapors given off by wood which burns too, if you look closely at a match burning. If you ever try to light a brush pile using diesel it can be a struggle to get it to vaporize to light.

    Jet fuel and kerosene are the same thing just cleanliness and additive differences, he really didn't mention that. I've used discarded jet fuel in kerosene lanterns for years.

    I don't think No. 2 diesel and heating fuel are the same. Heating fuel is a little heavier material but obviously from the video you can't tell the difference by looking.

    I was surprised to see the gasoline burn. When I was in high school working in a filling station the mechanic liked to say gasoline would not burn and would throw a lit match in a bucket of gasoline. The match would go out every time. I can only suspect that the flame passed from a lean mixture just above the bucket to a rich mixture just below the rim and would be snuffed out. I've never tried that but like most people have seen the flame follow gasoline vapors when I was stupid.

    While the glass jars were great for visibility that was very unsafe if he had a flash fire while messing around.

    I really enjoyed the video.
     
  3. DavidF

    DavidF Administrator Staff Member Banner Member

    If someone wants to put together a "time" to complete combustion per the specific fuel @ the proper a/f ratio for the fuels maximum flame temp to the cfm of air required then calculate the required combustion area whiule of course considering the change in combustion time over temperature increase then we will know approximately how larger of a combustion chamber we would need for a given fuel....
    AHH Propane :D Now where is my beer ? ;);) :p:p:p:p:D
     
  4. PatJ

    PatJ Silver Banner Member

    I made the mistake of pouring a half a gallon of diesel on a smoldering fire that I was trying to get going.
    It made lots of smoke, and then WOOOOOOOOOSHHHHHHHHHHH, a ten foot flame that just missed my head.

    Never mess around with hot diesel, or diesel poured on something hot.
    That is why I would not use a preheater for diesel for a burner.
    In my forgetfulness I would no doubt blow myself off the planet.

    .
     
  5. DavidF

    DavidF Administrator Staff Member Banner Member

    Yea, time, fuel, temperature, Woosh!!! :D
     
  6. crazybillybob

    crazybillybob Silver Banner Member

    Been there done that......but was standing in the middle of the brush pile when it went WOOOOOOSSSSSSSSHHHHHH....... With 4 Gallons of it in a plastic jug in my hands. Very glad I was wearing my Brown pants that day! (buddies failed to tell me that this particular brush pile was built on the site of the brush pile they burnt that morning (Lots of hot coals). How I walked out without a scratch or singed hair on my head is a miracle!!!
     
  7. Chazza

    Chazza Copper

    As mentioned before, the fundamental principle of combustion, is that anything that burns, has to be converted to a gas, before that can happen.

    In a petrol engine the fuel is vapourised, either by carburettor or nozzle, and then relies on the heat of the engine to help the droplets convert to a gas; in a diesel engine it is the same deal, except that the heat of compressing air, converts the droplets to a gas. Volatility of the fuel in the video explains why some fuels ignited i.e. the petrol (gasoline) was already converting itself to a gas by evaporation.

    More importantly for we furnace users, is to consider what this potentially explosive gas that we have created, can do. Gasoline fumes have 5 x the explosive force of dynamite apparently! Propane (LPG) is worse; many tradesmen have been killed by LPG leaks in confined spaces. The last one I read about, was a plumber who kept a small LPG bottle in his work van over-night. When he opened the door in the morning, a spark from the interior light ignited the mixture blowing the van apart, killing himself and his father inside the house. Most of the windows in the neighbourhood were broken.

    A furnace with the lid on, is close to a bomb when the fuel has been vapourised and not yet ignited. If you use propane for warm-up be very, very careful about your lighting procedure. my suggestions are:
    • Always take the lid off the furnace before lighting.
    • Only use approved gas-fittings when constructing the propane part of the system. In Australia it is illegal to construct it yourself, only a gas-plumber is allowed to. Propane is very heavy and can pool on the floor, waiting for a spark to ignite it!
    • Get a good fire going in the furnace to ignite the gas, so that it cannot pool in there and create an explosion.
    • When adding waste oil, follow Andy's video on how he he lights and runs his furnace. Waste-oil gas will blow up as well, if it gets the chance!
    Be safe out there!

    Cheers Charlie
     
    Tobho Mott likes this.
  8. oldironfarmer

    oldironfarmer Silver Banner Member

    Well put, Charlie!

    When using propane everyone knows if you have a flameout you have to shut off fuel and open the furnace. At that point it needs to air out, or if you're daring, throw a lit wad of paper in and let it go WHOOSH.
     
  9. PatJ

    PatJ Silver Banner Member

    There was a guy on the other forum who built a siphon nozzle burner, and was trying to light it.
    He had no clue about how to go about adjusting an oil burner, and so he shut the lid and was jerking the valves around.
    The burner flamed out, then it relit (he may have relit it), and he launched his lid over the roof of his house (according to him).
    When in doubt, and if you are not familiar with an siphon nozzle burner, start it extra rich, so that it does not blow out when you turn on the combustion air blower.
    And don't close the lid until you are sure the burner is operating in a stable fashion (applies to any burner type).

    And for the drip type, they are prone to puddling fuel inside the furnace at first, especially if you are new to them like me and not sure exactly how to operate one.
    You don't want to suddenly flash the fuel in the bottom from a liquid to a vapor.

    .
     
    Petee716 likes this.
  10. Chazza

    Chazza Copper

    Excellent advice Pat and Andy!

    Having not built an oil-burner yet, I have been giving it some thought and I think this is one safe possibility for myself, given that my foundry is inside and attached to my main workshop, which I do not wish to destroy.

    • I already have a legal LPG (propane) burner and gas setup, which is portable and easily adaptable; this burner could be used to warm the new furnace via the tuyere and at the same time warm the crucible ,which will be sitting on the lid.
    • When the furnace is looking hot enough and the crucible warm enough, I can remove the lid and dump a generous handful, or two, of charcoal into the base of the furnace and allow it to catch fire.
    • The lid can be replaced immediately with a flame-trap, made of stainless or copper mesh to catch any sparks and stop the shed burning down.
    • The LPG burner is removed and the waste-oil burner inserted and the air blower started on very-low-speed to get the charcoal well alight.
    • Once the fire is going well the waste-oil is added with the flame trap still in place, until it is obvious that the charcoal has gone and it is safe to remove the trap and put the crucible and lid in place.
    As I only want to melt aluminium quickly, I think this will work provided that I can make a drip-burner that works. Charcoal is very easy to make and costs nothing other than a bit of effort.

    Any thoughts?

    Cheers Charlie
     
  11. Ironsides

    Ironsides Silver

    Hmmmmm I have broken the law making my own furnace and burner! I hang my head in shame!
     
    _Jason and Jason like this.
  12. Jason

    Jason Silver Banner Member

    Shame on you, you're such a rebel! lmao:D
     
  13. PatJ

    PatJ Silver Banner Member

    If that is the case, then you had best get in compliance immediately by sending that furnace and burner up this way.
    And since the castings were made with the same furnace and burner, you had best send those up with the equipment.
    I will send you my address.
    Finally I will get a working drip-style burner.
    God works in mysterious ways. :)

    .
     
  14. oldironfarmer

    oldironfarmer Silver Banner Member

    Seems like a lot of effort. I guess I'd try to put the propane burner on a branch of the drip oil burner. You can light the propane inside the furnace and warm the furnace with the crucible already in. Then when the furnace gets red turn in the oil and air and shut down the propane. I just have a tee off my burner tube for propane and it finds it's way to the furnace. If you can block the propane air completely you can start with the blower turned way down. It's really nice to turn in oil and let propane burn it initially.

    If you want to swap out burners I'd put the charcoal in when the furnace is cold. It will light right off and then will burn oil
     
    Chazza likes this.
  15. DavidF

    DavidF Administrator Staff Member Banner Member

    Sounds like you need to build a bigger burner as your current one has not attracted enough attention. Aim high, melt the moon!!! :D
     
  16. Petee716

    Petee716 Silver Banner Member

    I would just leave the propane on a little longer and skip the charcoal. What Andy suggested in his last post is a good way to go. The oil will be more likely to extinguish the charcoal. Then you'll have hot smoldering oil in an almost-hot-enough furnace, a lot of smoke, and a potential flash hazard, not to mention the inevitable sparks. Get your walls hot enough to do the job of vaporizing the oil with propane, introduce the oil either gradually or all at once depending on the effectiveness of your pre-heat, and you'll be up and running.
    As an aside, I've had pretty good luck making charcoal effectively but it's messy and can be hard on the lungs. I've moved on.

    Pete
     
    Chazza likes this.

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