Oil Burner for furnace

[awemawson]

I've been poking around an oil fired central heating boiler today (one of three in our 'establishment' ) and was thinking, if I scrap it what would be useful.

Now these boilers are all pretty standard and use a burner system that atomises oil and blows it through an ignition system into the guts of the heat exchanger. Now that burner is a bolt on easily removable unit that could be reused ....


.... in a FURNACE to melt metal. 

My furnace is sitting under tarpaulins  waiting to be re-comissioned - perhaps this would be a suitable source of lots of heat.

This particular one has an output of 25kW according to the blurb. How does this compare to the various home made burners people use?

Random web sourced picture of burner follows:


Andrew

[Meldonmech]

Hi Andrew

                  When I built my propane furnace, I needed to research the subject in detail before embarking on the project. There is a wealth of information on  " BackyardMetalcasting.com " that includes oil firing. Another useful site is " Alloy Avenue ".
I have taken apart several of the combi type oil central heating boilers, just for the diecast parts, to remelt. I am sure the fan will be useful, the rest I think would depend on what type of oil you use. Many of the furnaces I have read about use reclaimed oil, such as that from fish and chip shops, I think this would require different jets etc. than you have in a central heating oil burner. Having said that your unit could possibly be modified. After reading and digesting vast amounts of material, I found I had to carry out experiments using differing burner designs before a satisfactory result was achieved.
                                                                                                                                        Good Luck      Cheers David

[awemawson]

This one uses 28 second ch oil which is very similar to red diesel .... I keep a 5000 litres bowser of red for use with the tractor etc 

Some time back I had a 'Morgan No 5' oil fired crucible furnace that I mounted in a pit for safety. Now that WAS a beast - would melt up to 1 cwt of cast iron at a time - I seem to remember calculating from its diesel consumption that it had an input power of nearly 1/2 a megawatt 

Sadly that had to go when my neighbour sold the bottom of his garden for building and I ended up with someones kitchen 10 foot from my foundry 

Andrew

[chipenter]

Hi Andrew I am shure that it could be made to work , but your question should have been is it economicley viable , if you can slide it in under the radar under farm heating and can claim back VAT on it may be .

[vtsteam]

Sorry Andrew that I hadn't seen this when you posted it -- just found it reading up on foundry posts, as I hope to start casting again soon. Your original question was never answered, so here goes just my own experience with my waste oil burner.

The setup:

4" thick firebrick lining
chamber, about 7" diameter
homemade atomizing burner
time to melt an A6 crucible of cast iron scrap, about  1-1/2 hrs (from cold)
fuel, diesel with or without about 10% used motor oil
fuel consumed per melt, about 1-3/4 gallons (US measure) (from cold)

So say about 1.4 gallons/hr
Say 130,000 Btu/gal (US)

Fuel heat input = 182,000 Btu/hr
or 54 kW (fuel input)

You can make adjustments for efficiency of burner(s), burner actual power vs fuel potential , and efficiency of your planned furnace construction - and its size compared to mine, but at least you have a data point here.

[awemawson]

No problem Steve 

That particular one went for scrap with the boiler. I noticed a few weeks ago one of our Scandinavian contributors was using such a boiler burner - don't remember who - but it's obviously possible. I'll probably put out feelers with my 'oil boiler man' who has installed three boilers here and does our servicing - he owes me a favour, I'm storing four of his motor bikes while he moves house   

[DavidA]

Andrew,

...I keep a 5000 litres bowser of red for use with the tractor etc  ..

Don't get caught using your 'etc' on public roads.

Dave

[awemawson]

No way - they confiscate the vehicle as well as fining you!

I've been 'dipped' three times over the years - all in London - never would consider using Red on the road - not just the morals - the consequences are too large.

Once was just south of Tower Bridge - hardly agricultural. Last time was near my house in Bromley. I'd gone out to fill up, went round a large roundabout, through the police point unstopped and on to the filling station. Came out of the filling station and they stopped and dipped me 

[Jonfb64]

Check out Myford boys YouTube channel. He is currently building an oil fired furnace having completed an oil burner that looks easy to make. Colin Peck has also done one he has also done a book which is pretty handy.

Jon

[Zadig]

Andrew, I use a domestic pressure jet burner in my furnace and I love it to pieces. I think the last nozzle I bought was a .6gph with a narrow cone to stop impingement on the crucible. I have no problems getting to temps for all the bronzes and it might just be on the cusp for iron although I have never tried. I have used a 1gph nozzle in the past but it's too rich for my set up as it stands.

I'm using waste motor oil cut back with a bit of domestic heating kero. I've used veg oil but although it burns well it tends to gum up the pump when the burner is left for a few months without use. The controller was scrapped and replaced by three switches: fan on; pump on and ignition. I don't use a filter for the oil but probably should and might do in the future, but as yet I've not had any problems. They are clean and easy to use and I cannot recommend enough.

[appletree]

No way - they confiscate the vehicle as well as fining you!

I've been 'dipped' three times over the years - all in London - never would consider using Red on the road - not just the morals - the consequences are too large.

Once was just south of Tower Bridge - hardly agricultural. Last time was near my house in Bromley. I'd gone out to fill up, went round a large roundabout, through the police point unstopped and on to the filling station. Came out of the filling station and they stopped and dipped me 

Bit off subject years ago we had a flat back plant hire delivery truck (2.3 ltr PETROL Bedford CF) the powers that be pulled my mum over and requested to dip the tank. 
No problem she said, a couple of minutes later the guy came back and said you've wrecked my gear why didn't you say it was petrol, you didn't ask you just said can I dip your tank and I said yes.

[vtsteam]

Nice looking rig! 

It's similar to mine, except for the nice all-in-one burner unit.

On mine, the functions are all separate -- fan is a vacuum cleaner, pump is compressed air from compressor, and nozzle to atomize is made up from bits.

Ironman uses the simplest setup with no compressor or pump (I believe), and just the vacuum cleaner and tube drip injector. I'd like to try that at some point to see what the difference is, if any.

He preheats the furnace with propane to start on the larger furnace. This is necessary because the oil isn't atomized.

I just light with a torch because the oil is atomized. And yours has the ultimate convenience of electrical ignition plus high pressure atomiztion. Too bad it doesn't have a powerful enough fan to burn a higher gph with a neutral flame. A second smaller fan and tuyere might help if you wanted to melt iron, but then you're away from the nice all-in-one concept.

Hmm, you just started me thinking, if I added a spark plug and coil to mine.......

[awemawson]

Zadig, thanks for that - I certainly think it's the way to go for simplicity - my furnace is still under tarps awaiting re-installation.

(Do I spy a Clarkson T&C grinder lurking in the background of your shots ?)

[Zadig]

Thanks Steve. I might have a play with adding more air one day, even if it is just for curiosity. There is a big aperture on the rear of the burner which would be ideal for attaching another blower.

Andrew, yes it is a MK1. It is a little tired and wants the feed screw replacing. God knows how Clarkson ever used these things in a commercial environment without bellows and slide protectors. It gets used a lot but as usual, the repairs are on the "to do" list.