David,

yes, I'll see if I can get such an aquarium pump, which runs at 12V. My needs seem to fall between the fan and the pump. Meanwhile, i will try a 60mm fan I bought yesterday. Its static pressure is not high, but it has more air capacity. I will try this today, with the 1mm jets in that copper tube drilled up to 2mm.

The fine, thing with this kind of mod, is that I will not destroy the original stove, and it can still work if the fan or the 12Volt fails.

Arne.

PS, 14.9.2017: That 60mm fan didn't work at all  -  way too low pressure.

Arne Kverneland wrote:

Origo 3000 alcohol burner with air injection  -  an experiment.

Any suggestion about that fan/air-pump?

Arne

  

BTW. I think you owe me an email :-)

Origo 3000 alcohol burner with air injection  -  an experiment.

Lately, I have been pondering on how to improve my Origo 3000 alcohol stove. The thing is, this stove is so simple, safe and reliable in use that I don’t want to throw it away.

Its big drawback is that it has an incomplete combustion when running at anything over the lowest setting: The flame is yellow, which is a typical sign of rich burn; plenty of fuel, but not enough oxygen. All other stoves running on a liquid fuel solves the task by turning the fuel into gas before injecting it into the air, but most of them need some sort of pressure.

Now I decided to try doing it the other way; injecting air into the rich flame to complete the combustion. This is how it is done in modern wood stoves/heaters, and the result is that the wood burns with a blue flame. The heaters stay clean, and so do the chimneys  -  and the heaters produce much more heat on a sack of wood.

Tonight I took a piece of copper tube with me to the harbour workshop and prepared it as on the photo below, with five 1mm holes in it, and the end closed (pinched flat) in the vice. This I took on board in Ingeborg, together with my car tyre pump. The two other photos below tell the story (sorry about the poor quality, I only had my old mobile phone). With the burner turned high, the flame was, as always, bright yellow. When I connected the tube to the pump and injected air into the flame, the flame instantaneously turned blue and intense, sounding like a gas flame. I only operated the pump very slowly. I bet the pressure was no higher than we can blow ‘by mouth’. I find this experience to be very encouraging: I will shape another tube into a circular shape with about twenty 1mm holes in it. This, hopefully will ensure that the whole flame gets enough air to stay blue all over.

Then is the challenge of finding a cheap and quiet 12V fan which draw little power. Anyway, if the battery is low, the Origo will work in ‘the old way’ without air injection.

Any suggestion about that fan/air-pump?

Arne

Yes, that modkit to make a primus burn alcohol made me too curious. Ethanol has a lot lower boil temperature than kerosene, so maybe it is some sort of flame damper of shield, which limits the heating of the burner? Or maybe it simply is a jet with a smaller (or bigger?) hole? Quite confusing this, since a volume of alcohol only produces about half the energy of what kerosene does.

Arne

Bruno Gouget wrote:

Here , a german (in german language!) site with a lot of spares .

Have good cooking !