Thread: Oil burning shed heaters

Originally Posted by rovercare

Get the pics up!

Mine melted, I think when I buy a press I'll just press a mild steel plate concave and use that, just oxy it cherry red, should get it going, unfortunately time constraints wont see me playing heater games any time soon

Forget the oxy that's way to expensive to waste, if the plate is not to thick you should be able to light it the way you did with the ally dish, I used diesel and a rag for a wick, as I said before just a bit slower.

Press smesh get a big hammer and beat it into shape it doesn't have to be pretty.

Originally Posted by db65boxer

Forget the oxy that's way to expensive to waste, if the plate is not to thick you should be able to light it the way you did with the ally dish, I used diesel and a rag for a wick, as I said before just a bit slower.

Press smesh get a big hammer and beat it into shape it doesn't have to be pretty.

Oxy for speed!, more interested in being able to warm the shed of a nighttime after workies and get straight into working on the jobs, instead of shivering

This is a little one I knocked up in some spare time at work a couple of years ago to test the theory before going large scale with t hot water service.

Worked well other than the nasty fumes from the Gal gas bottle so it was canned and I made one from painted gas bottle and an air compressor receiver instead which I can't seem to find photo's of.

This one worked but the flew was too short, not enough draw, the second one had a longer flew and a taller chamber which worked very well but was trashed when OH&S came through, apparently it wasn't safe

I have also found the M/E Sanders heater (Sputnik) can be temperamental. Seems to be a very fine line with height, flue length, vaporizer sises/heat and oil metering. Mine takes up to 30minutes to get running stable at times

I like Ozzirt's pre burner idea a lot better.

Orright!
I am about to embark on a build of one of these critters.
Will start with Ozzirts design but.......
I am not actually building it (my boilermakers are) and they are pumping me for information.
So maybe Mr Ozzirt, you might like to fill me in with some answers to their questions....Please.

I have printed your drawing from a few pages ago and it seems clear but...(the side view link is bruck)

1. How 'airtight' does the pan and the lid need to be? (We have spent hours drawing Bernoullis principal and associated math on the whiteboard and ended up just yelling at each other - quite funny aside actually, I'm the engineer so just build it I said, it's magic....We're the tradies and it won't work they say ).

2. Detail as to the design and what's inside the primary pan is a little confusing (to me anyway). Are there any particular specs for the fuel feed trough?

3. Whilst I consider myself smart, the theory of these critters does my head in. Here's how I think it works: oil in the pan just plain ol' dirty burns, but when drawn through the secondary burner, the extra oxygen forces a cleaner hotter burn. But it actually should vapourise in the primary, not burn.....'pleeease explayn'.

4. Is there any reason I can't just weld the two rims together rather than use throughbolts?

5. I actually intend to adapt your fine design and use it to heat my pool! Any modifications or changes you'd recommend at the pre build stage to achieve this?

Regards and pardon the questions

Ralph

Originally Posted by Ralph1Malph

---snip---
I have printed your drawing from a few pages ago and it seems clear but...(the side view link is bruck)

Ta!,... I'd better look at that.

1. How 'airtight' does the pan and the lid need to be? (We have spent hours drawing Bernoullis principal and associated math on the whiteboard and ended up just yelling at each other - quite funny aside actually, I'm the engineer so just build it I said, it's magic....We're the tradies and it won't work they say ).

Righto Ralph, I'll do my best.
As airtight as possible without the need for gaskets etc. Mine was a good metal to metal fit, but now has a gap of about 1mm around 10cms of the pan edge (slight heat distortion) it still works OK. Any tradie worth his salt can build it and make it work,... considering that a Public Servant built one in about three nights after work and has been using it in his home for about four years now. [ame="http://www.youtube.com/watch?v=FvcgokYbpAg"]YouTube - ‪Waste oil heater‬‏[/ame]

2. Detail as to the design and what's inside the primary pan is a little confusing (to me anyway). Are there any particular specs for the fuel feed trough?

The feed/preheat trough is all that is in the pan, it should extend to the centre if possible, mine is slightly shorter, but still works OK. This has a twofold purpose, 1. It acts as an oil heater negating the use of a preheating coil, these are a pain, as they usually coke up when the heater is running at high temperatures and there is no convenient way to clean them. 2. It dribbles the oil into the centre of the pan where it gets the most heat, both from the primary burning and also radiated heat from the flame in the secondary burner above it.

3. Whilst I consider myself smart, the theory of these critters does my head in. Here's how I think it works: oil in the pan just plain ol' dirty burns, but when drawn through the secondary burner, the extra oxygen forces a cleaner hotter burn. But it actually should vapourise in the primary, not burn.....'pleeease explayn'.

Close,... The oil in the pan partially burns in a low oxygen environment providing heat that vapourises the remainder. This vapour in turn rises through the primary flame and radiated heat from above, forming a hot carbon rich vapour which in turn rises into the secondary burner where it is vigourously mixed with fresh air, this supports the secondary flame where most of the heat is generated.

4. Is there any reason I can't just weld the two rims together rather than use throughbolts?

Welding large cast steel parts can be problematic requiring pre heating and temperature control whilst the welding is done with low hydrogen electrodes or similar. It could also make your assembly/disassembly more difficult depending on how you are going to hold the rest of it together. It would also make the firebox assembly bloody heavy and awkward to handle, should you ever need to do any maintenance.

5. I actually intend to adapt your fine design and use it to heat my pool! Any modifications or changes you'd recommend at the pre build stage to achieve this?

Regards and pardon the questions

Ralph

I believe that there is already one being used in WA to heat a lap pool in the home of a paralegic gentleman somewhere down around Margaret River.

If you can find one use a large cast iron camp oven as a primary pan as the come with a close fitting lid, they are also cast iron and resist burning and distortion.
Drill all of your airholes undersize to start with and enlarge them as needed.
Use 15cm flue and a similar sized secondary burner tube, preferrably on old cylinder liner. They are soft and easy to work and also resistant to distortion.
The height of the secondary tube is not important, but for maximum efficiency it should be about "square" (similar height as the internal diameter)
One large row of holes near the bottom for radiant heat into the pan and another row about half way up. (32 holes x 10mm dia in each row) This combination seems to work well.

Not everyone is a masochist, and questions and answers may save you a lot of frustration.

Originally Posted by ozzirt

Ta!,... I'd better look at that.
As airtight as possible without the need for gaskets etc. Mine was a good metal to metal fit, but now has a gap of about 1mm around 10cms of the pan edge (slight heat distortion) it still works OK. Any tradie worth his salt can build it and make it work,... considering that a Public Servant built one in about three nights after work and has been using it in his home for about four years now. YouTube - ‪Waste oil heater‬‏
The feed/preheat trough is all that is in the pan, it should extend to the centre if possible, mine is slightly shorter, but still works OK. This has a twofold purpose, 1. It acts as an oil heater negating the use of a preheating coil, these are a pain, as they usually coke up when the heater is running at high temperatures and there is no convenient way to clean them. 2. It dribbles the oil into the centre of the pan where it gets the most heat, both from the primary burning and also radiated heat from the flame in the secondary burner above it.
Close,... The oil in the pan partially burns in a low oxygen environment providing heat that vapourises the remainder. This in turn rises through the primary flame and radiated heat from above, forming a hot carbon rich vapour which in turn rises into the secondary burner where it is vigourously mixed with fresh air, this forms the secondary flame wher most of the heat is generated.
Welding large cast steel parts can be problematic requiring pre heating and temperature control whilst the welding is done with low hydrogen electrodes or similar. It could also make your assembly/disassembly more difficult depending on how you are going to hold the rest of it together. It would also make the firebox assembly bloody heavy and awkward to handle
I believe that there is already one being used in WA to heat a lap pool in the home of a paralegic gentleman somewhere down around Margaret River.

Not everyone is a masochist, and questions and answers may save you a lot of frustration.

Thanks for replying so quickly.
I reckon I understand it all now so let the build begin!
Got most of the ingredients and if the proto works well, I'll use it to warm the rec area and the next one is destined for my pool! I reckon I'll just add a water jacket around the heat exchanger and use the pool filter to circulate it.

Funny to watch today, I was 'proving concept' to the skeptics who said I'd never get oil to burn simply with a kerchief soaked in waste thinners.
Well, I placed the soaked kerchief on the floor and lit it. Then grabbed a 300mm offcut piece of 50 mm gal steel pipe and placed it close to and over the burning kerchief.
I then dripped 100ml of cutting oil into the pipe...... instant proof of concept. We had a jetlike flame out the end of the pipe and the vapour ignited about 30mm out from the tube.

Got so hot the zink separated from the steel which went cherry red. Burnt for over 7 minutes on the soaked kerchief and 100ml of cutting oil!

The crowd was amazed in wonderment! I nonchalontly walked away and uttered to the tradies...just build it!

Cheers
Ralph

Build not going so well.
Can't get the draw right (maybe flue too short) and really have to get the lower chamber really burning hard before any sort of combustion happens.
Gunna fiddle around with the lower chamber tomorrow as I believe all the oil is burning there, not as it goes up the secondary chamber as it should.
Obviously, got a prob with air flow too, but we'll persevere.
There were moments of success but few and far between.

I'll endeavour to play by the rules and post a few pics tomorrow too.

Ralph