I know about the Nansen stove and the modern version, but if you look carefully you will see that the system does have a large exhaust port as a large diameter vent right around the pot. The large diameter counters the narrow gap.
My experience with some of those older designs for kero stoves has been that they are considerably less powerful than the modern canister stove. I have found it very hard to get a kero flame as large as a butane flame: little over 2 kW (kero) vs 3.3 kW (canister). That might be a bit surprising, but I think it is due to the difference in the number of carbons in the molecules, and the difficulty of getting enough oxygen mixed in. So they generate less exhaust gas.
The converted milk boiler is an interesting idea. We would all love some test results and measurements – please!
Cheers








