[Stoves] two different manners to start a fire

[Crispin Pemberton-Pigott]

Dear Martin

That is a good observation:

>What is the minimal speed of air, to make the charcoal glow with the
self-ignition temperature of woodgas? Bright glowing charcoal ! 
>Interesting to know exactly -- to keep the Tluds from smoldering by
accelerating the air-flow up to that speed. Just a tiny area of bright glow
on the upper surface would be sufficient.

If even one jet from the secondary air were to be poi9nting down at the top
of the char bed, it could burn a little of the char to keep that flame
going.

I think the problem comes when the gas is being generated in one place and
the flame is burning somewhere else 'disconnected' from the pyrolyser.

If the flame is close-coupled then the ignition would be continuous. I have
suggested that people put a couple of holes a little under the top deck as a
way to burn a little of that char to keep the top surface hot enough to
ignite. Blowing on the top is also a possibility with no more air than
necessary. 

For stoves with the gas burning 'remote' then perhaps we can take a lesson
from the model airplane engine with hot coil ignition. It used to be that
cars used hot tube and hot coil ignition - no sparks at all. 

The idea is there is a retained heat igniter in the flame all the time, If
the flame puffs out, the glowing red metal relights it if combustible gas
reaches it within 1 or two seconds. 

Thanks for thinking
Crispin