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Oil Burner design

Posted: Sat May 05, 2012 11:22 am
by Alster370
Id like to use an oil burner for various hobbies that I do , but I need it to be very compact, and so I drew up this (very crude) design. Hopefully you get the design, as it works similar to aerosol cans in the way that the air pushes the fuel up the nozzle, mixing with it as the flow is restricted.
Image

Please let me know what you think 8)

Posted: Sat May 05, 2012 11:50 am
by Gippeto
Design is highly dependant on fuel type. What are you wanting to use as fuel?

What you've drawn might work with low viscosity/low flash point fuels...but would never light with waste oil.

Aside...assuming it works as planned, you've only atomized the fuel. You still need a burn tube to vaporize the fuel for combustion. Can't burn liquids...only vapours.

An old siphon burner project...

Image

Posted: Sat May 05, 2012 12:11 pm
by Alster370
A burn tube would be a piece of steel or copper that sits on top on the fuel nozzle and is preheated before lighting?

And yes I would hopefully like to get this design to work with sunflower oil or similar.

Posted: Sat May 05, 2012 12:34 pm
by Gippeto
Many ways to make a burn tube...the one shown was the last one I worked with. Flared at the inlet and tapered at the outlet, it was the quietest (still bloody loud) and smoothest running one I made. ~240000btu judging by fuel burn IIRC.

Not necessarily preheated...an ignition source will add heat which will vaporize "some" fuel and the resulting combustion will generate MORE heat, which will heat the tube up and help SUSTAIN the combustion when the ignition source is removed.

I don't happen to have any sunflower oil on hand :) ... but the residential oil burners that use a pump and atomizer nozzle (such as you drew) use ~300psi to atomize heating oil...which around here, is nothing more than diesel fuel with a red dye added.

Most waste oils need to be preheated and still require significant pressure for atomization. A good burner for waste oils is either the Turk burner , or the babington babington....the turk is significantly simpler to build, but the babington can run for longer periods of time without service.

Judging by the drawing you made, I'm thinking you should have a look at a Turk burner.

Posted: Sat May 05, 2012 3:03 pm
by Heimo
this along with this is what the people on the home foundry forum I am a member of uses to melt cast iron with waste motor oil....

Posted: Sat May 05, 2012 5:57 pm
by Gippeto
Yup...siphon burner. :)

The pic above is burning a mix of used auto oil and diesel...~50/50 IIRC.

If you add such to a gingery style furnace, the refractory acts in much the same way as the burn tube...providing heat for vaporization.

Posted: Sat May 05, 2012 9:02 pm
by Technician1002
I hear about the temperature of burning oil, and then hear the conspiracy theorists that say the 911 collapse was not from the fire.

With a proper draft, and in a confined space to prevent radiant heat loss, it burns pretty hot. It burns much hotter than it would in an open space.

Posted: Sun May 06, 2012 3:47 am
by Alster370
Could my design work with a <70% spirits? I happen to have a few litres on hand. :D Besides I doubt I could get sunflower oil to run with this design, especially at a small diameter.

besides my tyre compressor is very small and can only deliver about 8cfm IIRC.

Posted: Sun May 06, 2012 8:52 am
by Gippeto
Not saying it won't burn, but 70% is still 30% water. The water will steal heat from the reaction...99.9% would be best IMO, but you SHOULD try what you have on hand.

You might get it to light without a burn tube, but I have doubts about whether it will stay lit or burn well. You may have some degree of success if you look at the nozzles from hand held sprayers...you need to break the fuel into as small of droplets as possible....ie....make a fine mist out of it.

Should go without saying, but this is most definitely not something to muck around with inside the workshop....must be outdoors.

Posted: Sat May 12, 2012 3:06 am
by Alster370
would there be no worries using meths n an oil burner design? Like this for example : http://www.backyardmetalcasting.com/oilburners09.html

or a design where pressurised air pushes the fuel though the atomiser nozzle


Id be worried about the high flammability :?