[Stoves] Inverted top lit updraught

[ajheggie at gmail.com]

One for Peter Verhaart to comment on perhaps: we probably all know by now 
the genesis of the inverted down draught stoves which Ronal and Tom Reed 
expounded early on this list and  concurrently Paal was developing with 
his early Peko Pe and we understand how burning the pyrolysis offgas can 
offer very low particulates compared with  burning whole wood in a 
conventional updraught stove but is the same true of a down draught stove 
if the primary air is similarly controlled?

The advantage of stratified down draught ( i.e. where the air moves down 
through the charge of wood as that also descends through the grate)  
would seem to be that  the fire can be continually stoked. The 
disadvantage is all the extra pipe work and either needing a hot plate or 
sunken pots to maintain the chimney depression required to suck the 
primary air down.

Down draught devices are normally intended to gasify all the fuel, often 
with extra air supplied in the "throat" but what if one was not 
particularly concerned if a high char ash were left?

For the sake of staying on topic can we avoid the "b" word and just 
discuss the concept?

AJH