Best Burner For Larger Furnace

Yes you can burn diesel in a drip oil burner. Mine uses an old Fire extinguisher as a tank, and the compressor pressurises it. I use 50:50 Diesel and waste oil, for the reasons Jason explained above. Diesel makes it flow better and more predictably, and doesn't need preheating. As a drip burner won't work into a cold furnace, and you are going to have a huge furnace, you will need a lot of propane preheating. For your application a kwiky sounds like a better option. Myfordboy has a good description if making one on his website.

 

I bought a deLaval siphon burner but built a drip burner first. I have no desire to use anything else. I just keep it adjusted so a little flame comes out the flue. It will burn anything flammable including gasoline, ATF, and transmission grease.

My furnace is basically half of a 55 gal drum and a small burner does just fine. I use a cheapy leaf blower which has 450 melts on it.

 

So, Andy, I think I read your post to mean you like the siphon burner? I guess I am dense, but thought there was some ambiguity.

I too use a nominally 1 gal per hour Delevan siphon pushing 2.5 gal per hour of diesel through it and use a small electric leaf blower stopped down with a shutter valve. It provides all the burning power my furnace can use as I could run it much harder. But if I run more air and fuel through the burner, the fuel does not have time to burn in the furnace. So, I just waste fuel and have a cool furnace.

I keep mine tuned a .18L per minute and use enough air to have a reddish flame (not bright yellow) extending a foot or slightly less out my 8 foot tall 6"I.D. muffler which sits on the furnace lid opening. I suspect that means you and I run a pretty similar air/fuel mix.

Denis

 

I see how my post was ambiguous.

I like my siphon burner but have never installed it. It's very shiny and pretty though.

What I use is a drip burner coming from an air pressurized fuel tank, through a filter then a good quality needle valve and a run of brake tubing to the end of the air tube. I start on propane and use a cheapo leaf blower through a knife valve. It just works too well for me. I run about 6" of yellow flame out the top of my furnace charge hole and can melt 2,600F brick. It melted cast iron very well for me.

Everybody has different criteria. I don't care about fuel flow, I do care about using free fuel. I don't mind fiddling with my propane on warmup nor do I mind occasionally adjusting the needle valve to get the right amount of flame out the top during different conditions. I burned a fair amount of stale gasoline and it does not burn as hot as motor oil. I also have contaminated diesel but most of what I burn is old motor oil and transmission fluid. In a hot furnace it all burns well with no smoke. Using propane to warm up I get very little smoke except when I mess up and do something like turn off the air.

 

Andy and Dennis, I would love to see video of both you lighting your furnaces from a cold start. I think I've seen both Jeff and Jason do a video of cold start up.

Maybe David could start a sticky thread and show us his cold start up with video. I don't think there's enough words to explain everything. I'll definitely join in with video.

 

Well, I will try to video it next time. Suffice it to say that I simply soak a blue paper towel with some diesel fuel, light it, and drop it into the furnace. Then I open up my combustion air to a very low setting---just a gentle breeze blowing through the burn tube and set my atomizing air on 10 pounds. Then I crack open the fuel on the burner and it just gently and quietly lights. No drama. Then I just open up the fuel and air alternately so as not to cause a lot of smoke. Smoke I could personally care less about, but I try to keep a visual low profile. After 20 to thirty seconds things are in the general range of burner setup and I close the lid. For the first five to ten minutes I make occasional adjustments to fuel and air since the furnace becomes more reactive and efficient as it warms up. Once it is getting good and red inside, I then have to make few if any adjustments. In the last ten to 20 minutes of a melt I do tweak the fuel/air mix for the hottest possible burn as the metal and flame are not that far apart in temp and 50 degrees hotter makes the burn significantly shorter than a slightly cooler furnace temp.

Denis

 

Dennis. Your full description above with a video would be awesome.

My description of cold lighting:

I have two burners. I pull one of them out of the furnace and hold close to it a handheld propane blowtorch. I introduce the air and then the diesel well pointing it into the top of the furnace open. Once it lights I have a flamethrower shooting into the top of the furnace... Now, I turn on the second torch burner that is installed in furnace. When the installed one holds the flame, I turn off the one in my hand and the propane blowtorch. I quickly install the second torch/burner turn on the air slowly and the diesel slowly. In about two minutes I can close the lid. 5 to 6 minutes later I can switch one of the torches over to WVO and the second torch about 30 seconds later.

I do to get a double pressure of extra lean on the switchover. I guess I need to show a video.

David would have to start a new sticky thread for diesel oil cold starts. Maybe he could even show us how he does it.

Maybe somebody could start a thread with videos with cold start switching to oil and then maybe David would sticky it here (and maybe join in with his own).

I personally found this the most difficult information found on the Internet. Jeff on this site gave a best description video.

I have gone against the grain....but, Bigger torches, don't always deliver bigger radiant BTU.

I actually find diesel to be the hottest fuel. But once the furnace is above 600°-ish Celsius, if you can push in the free WO or WVO it now becomes fun.

 

Here's one I made a while back. Note I don't use newspaper anymore. I just lay a lit match in the bottom of the furnace and let the propane find it. I'm not using a SS crucible either.



And one of the furnace operating on oil. I do find motor oil to be hotter than diesel with the drip burner.

 

Andy, thank you. I just learned something new from 14 minutes of your videos

 

Oh no!! You learned how bad I am?

 

The other question for you, Andy, is, when melting aluminum, do you intentionally run the furnace at less than maximum heat? Seems like it would make sense to do so as reducing the heat some would save wear and tear on the furnace but still provide a high difference in furnace temp over aluminum temp to provide rapid melting.

Denis

 

Not at all. I like how you reduced the inside bore with sacrificial brick. They look like they're loosely laid. As well, it looks like you found some kind of ceramic rope gasket to separate the furnace from the lid.

For fun I just dropped in 4 bricks to see what it looks like.

 

Those wide brick make it look pretty tight to me, interesting to see how it works.

My entire furnace is laid with loose brick. No mortar joints have cracked yet.

My supplier had one box of ceramic fiber rope. I asked for 20 ft and they charged me for twenty feet and gave me the box. I'm not sure how much is in there but I'm sure I could spare some if you can't find it.

 

My furnace is pretty much loose laid brick with mechanical straps (large hose clamps) lightly squeezing the bricks into a circle. Even the lid and bace on mine, are loose laid bricks with some mechanical strapping. I did mortar up a little extension flue (with some advice from some fine fellows here) with mechanical strapping again.

I'm thinking the sacrificial bricks for down the road (when I enter into the cast-iron). The pictures above are showing an A12. This is going to be my new aluminum crucible. When I go to cast iron, I might implement the sacrificial bricks with an A8.

Thank you very much for your kind offer. I might take you up on this, if I witness any destruction with a copper melt.

 

On my furnaces I have used siphon nozzles with a propane back burner. the propane burner is used to stabilize the flame on cold start or when i open the lids on the tilting furnaces. I also shut down the oil burners on the tilting furnace when I open the lids to reduce the heat when adding metal etc. the siphon nozzles respond without a lag or smoke, and can start and stop easily as well as having a large firing range based on feed and siphon pressure, they also lend themselves to control with servo operated valves..

If I'm understanding your process you will be melting and dipping out of the same melt pool. the metal temps will vary substantially depending on if there is unmelted metal in the pool, the reason I use a tilting furnace for melt and a separate crucible furnace for drossing and pouring temp stabilization is because the melting temp is about 200F lower then the pouring temp, this temp difference generates a marked viscosity change in the metal, if there is any unmelted metal in the pool the entire pool will be at the melt temp.... think about ice water as long as there is unmelted ice in the water the entire glass will be 32F

My system controls the burner firing rate based on furnace temps. With your system there will be a major firing rate difference between a melting operation and pool holding operation, my tilting furnace has a holding pool and holding firing rate is between 20 and 30% of the melting firing rate.

Burner efficiency is about the same from one style of burner to the next. if the fuel is at or above ignition temperature, is sufficiently atomized or vaporized, and there is enough mixed oxygen (combustion air), you will get 100% combustion defined by: on gas 0% CO, on oil 0% CO and no unburned vaporized oil (black smoke) excess combustion air ( reduces the flame temp and in our furnaces reduces the transfer of energy to the metal.. furnace efficiency on the other hand is measured by the amount of unused energy, flame rollout is unused energy and thus lower efficiency, it also represents more fuel then air or more fuel then furnace volume either case will normally increase flame temp. If it is more fuel then air, the area closer to the burner will not have flame and can cause a flame out.

My max firing rate is any flame exiting the furnace. on initial adjustment I'll increase fuel until i start getting flame rollout, I then increase combustion air, if the flame pulls back into the furnace it hasn't reached the max fuel or flame size, i keep increasing fuel and air until adding air increases the amount of flame rollout, this is the furnace max based on volume,I then back off fuel and air until I am just starting to get roll out. this adjustment is max firing for that furnace and fuel source. it will also generate the highest flame temp.

For me the reason for using siphon nozzle burners is mostly a firing rate automation issue.

I hope this takes some of the magic out of burners.

Art B

 

Well, seems like a pretty basic video, but here it is:



FWIW

Denis

 

Thanks Dennis. I tend to get the black billowing smoke for 30-ish seconds. I also find if I try to close the lid too quickly, I get a diesel flame out. I'll see if I can put a video together this weekend for critiquing.

 

446. My wife dying slowed me down a lot. I'm finally getting back to doing a little.

Yes and no. I run on motor oil with my leaf blower on low speed. I turn it up to high speed for cast iron. But for copper, brass, and bronze I leave it on low speed (and less oil to get flame out the flue). The ramp up rate for temperature gives me acceptable melt times for my operation. I usually melt as the furnace is warming up regardless of the charge in the crucible. I don't think the furnace gets more than 500F over the melting temperature before the charge is at pouring temperature.

Trying to think it through, I heat as fast as I can on low leaf blower air (which is plenty) and the cold crucible keeps the furnace from overheating.