The No.12 is a large pressure stove designed to run on diesel. It was standard equipment on the Scorpion tank and the Saracen armoured car.

I bought one of these a few months ago on Ebay and forgot about it. I dusted it off yesterday and had a go at lighting it.

I filled it up with B100 and tried to light it following the printed instructions. This involves filling the little cup below the burner with fuel and lighting it to preheat the burner. I pumped the pressure up with the recommended 20 strokes. I opened the valve and I got just a sputtering yellow flame and a fair bit of black smoke.
I turned it off and let it cool before trying again. This time I gave it 30 strokes and used a gas blowtorch to preheat the burner. After about a minute I opened the valve and hey presto, a roaring blue flame! I put on the kettle and boiled up the water for my 11.00am coffee, very satisfying.
This stove is much more powerful than the average camping stove and I hope to be able to use it to heat my yellow grease before filtering and using in my burner/boiler.
It could also be used to heat oil prior to biodiesel conversion.

I have found that the cooker will maintain its blue roaring flame for about 15 minutes before turning yellow. What seems to be happening is the vapourizer pipe is cooling down after that time. To help the vapourizer retain its heat I made a cylinder of perforated aluminium which surrounds the vapourizer. This reflects heat back while allowing air to flow. It works a treat. I was able to run the cooker for an hour yesterday with no problems.
This modification could be used on any pressure lantern or stove with good effect.
Ill take some pictures and post them soon.

Looking foreward to the pictures.

Here is the picture of the No.12 cooker running on B100. Its very clean, no smell and certainly no smoke.
Im using it instead of a butane/propane gas ring to heat my glycerol/yellow grease prior to filtering and using in my alaska burner/boiler. It has the same output as the gas ring. it will heat 20 litres of oil to 50 degrees C in about 20 minustes

Was it something I said? Since I posted this information the selling price of No.12 cookers on Ebay seems to have gone from around 80 GBP to around 150 - 160 GBP.

I wonder what is different about that stove than one designed to run on gas. My guess is the jet is bigger. I have two Optimus 111B gas stoves that look just about the same but smaller. The operating parts seem to be the same concept. I also have some brass kerosene/diesel stoves that use the same ideas but different shape.

Wonder if one of the differences is the material the ring is made of.

In a diesel type.... the rings material may be chosen so it acts like the catalysit/Pinapple gizmo we have been discusion in other threads.

As it gets hot it helps the diesel further automize and burn better as its fumes exit the little holes in the ring.

In a gas burner your already burning fumes so the ring is not intended to do anything but evenly distribute the fumes.

My stoves that burn kerosene have the same ring as the gas ones. They both need to get hot enough to vaporise the fuel but the ring is there to keep in some heat from escaping to the side.

quote:

Originally posted by Raften:
My stoves that burn kerosene have the same ring as the gas ones. They both need to get hot enough to vaporise the fuel but the ring is there to keep in some heat from escaping to the side.

not sure we are talking about the same thing.

are you refering to the ring/bowl it sits in in the photo. Keeps the flame and heat limited to the burner area?

I'm calling the donut shaped or what ever it is that has the holes in it for the vapors to escape from and get ignited into a circlular ring... This unit is what I was refering to as "the ring"

Right you are Coach, it would be interesting if IMake could post some close up pics of that burner. After you pointed it out I can see the holes in the rim, quite different from what I have.

Sorry guys, but Ive been away for the St. Patricks holidays. Ill post a pic soon.

Here at last is the pictures I promised. The first is the burner itself. As you can see there is a little dish on the bottom for preheating with liquid fuel. i dont use it because I preheat with a gas torch.
The other picture is the sleeve that I have made to surround the burner. It both restricts the airflow to the burner and also reflects heat back at the burner maintaining the hotter temperature needed to vapourise biodiesel.

Ive had some private messages asking questions about the No12. Just so I dont have to answer the same questions over and over Ill post the replys here.
To light the burner fuelled with biodiesel, give the pump 30 strokes instead of the recommended 20. Preheat the lower part of the burner with a gas blowtorch ( butane, propane but not mapp gas) for 35-40 seconds. Smoke will start to issue from the burner. Turn the knob fully anti clockwise to clean the nozzle and then back a bit to open the nozzle. Light with the blowtorch flame. If the flame is yellow and smoky preheat fore another 10 seconds without turning the flame off. Adjust the knob to get the best blue flame. Pump a little more if necessary.

I use 10% kerosene in the bio which makes it a little easier to light but its not necessary.

Someone was proposing to build a small portable biodiesel processor and using a no.12 to heat the oil. This should work and in answer to the question about heating capactiy I use mine almost every day to heat 20 litres of wvo up to 50 degrees C and it takes 30 minutes.

Prices On Ebay are slowly going back down, one sold last night for 127 GBP.

My No.12 cooker has become an invaluable piece of equipment. I use it almost every day and a few days ago I used it for five hours continously to power my methanol recovery still. 2 litres of biodiesel recovered 5 litres of methanol which will be used to produce 25 litres of biodiesel, not a bad exchange.
It is far more economical to run than a gas ring. A 34kg cylinder of butane gas costs 30 euro here. About 3 euros worth of biodiesel does the same work.

I have noticed that in recent weeks the control valve on my burner has begun to leak a little. sometimes when the cooker is running I can see a small yellow flame from the valve and wisps of smoke. Tightening the nut on the valve helps but it comes back again. Today I decided to strip the valve to see what was wrong. I removed the nut and saw a rubber o ring around the shaft which was obviously the problem. it was very difficult to get the old o ring out so I simply put another one on top and replaced the nut The problem has dissappeared. The biodiesel had melted the rubber. The replacement was a metric 5 x 2mm in Viton.

I have built a new methanol recovery still which has 2 heat sources. First a 3000w immersion heater quickly brings the glycerol up to boiling point then a British army no 12 cooker, running on biodiesel, takes over and maintains the still at a gentle boil.
The capacity of the still is 40 litres and should yieild 8-10 litres of methanol in about 5-6 hours.
Im testing it this weekend and will post results and pictures.

My new 40litre methanol recovery still worked very well at the weekend. I heated up the glycerol with a 3kw immersion and then switched over to the no.12 cooker which maintained a steady low boil for 10 hours. The temp of the reflux head stayed between 72 and 75 degrees C and produced 8 litres of 90% methanol. I could have kept going and distilled more but it got so late I had to turn off and go to bed.
One problem arose. The needle valve in the burner broke when I turned off the burner. Its possible the the burner is not suited for burning for such long periods. Ill have to take it apart to see what went wrong.

I have just replaced the burner in my no 12 field cooker and it is up and running again. I suppose the lesson to be learned from this is that the no 12 cooker is not meant for running for 6 hours or more. A short cooking time of an hour or so is fine . Back to the drawing board with my still, in fact I have been using a small electric hotplate which works perfectly for hours and hours.

I notice that someone is selling a no. 12 on Ebay, complete with pans for a Buy it Now price of £69. I havent seen a price of less than £100 for nearly a year. if you want to grab a bargain the item number is 370246199974