[Stoves] Pyrolysing side draft stove, 1982

Tom Miles tmiles at trmiles.com
Mon Jan 24 18:06:39 PST 2011

Alex, Crispin,

Interesting histories and experiences. If you remember the market for wood
stoves changed dramatically in about 10-15 years. There was a flush of "tin
wonders" right after 1973 and 1979 crises. 

Wood smoke became a problem in this time period. Our efforts to clean up
stoves resulted directly from a local study that found that 60% of the
respirable particulate - that would stay in the lungs and not come out - in
the air came from wood smoke. The rest came from other sources like

Then a decline after the oil prices receded in about 1985. I think that wood
pellet stoves actually took off starting in about 1985. I would imagine that
the market for stick wood boilers got started and then probably died in the
late 1980s. It seems to have resurrected only in the late 1990s when oil
rose again. That would make it tough to start a new company. More than one
wood boiler company has emerged and died in the last ten years.       

Another factor is that the design went through several hands. When this
happens people always have a better idea without necessarily knowing why
something is designed or built the way it is. It's amazing what gets built
wrong and then doesn't work. 


-----Original Message-----
From: stoves-bounces at lists.bioenergylists.org
[mailto:stoves-bounces at lists.bioenergylists.org] On Behalf Of Alex English
Sent: Monday, January 24, 2011 5:10 PM
To: Discussion of biomass cooking stoves
Subject: Re: [Stoves] Pyrolysing side draft stove, 1982


I helped install one of these in a big brick house in eastern Ontario 
back in the early winter of 81-82. It seemed to have all the answers but 
for a variety of reasons, not all of them were the stoves fault ( not 
unlike cooking stoves), it was a disaster. It ended up in court, the 
Jetstream was removed.

There is more at;



On 1/24/2011 7:43 PM, Crispin Pemberton-Pigott wrote:
> Dear Tom
> What a great backgrounder. I hope Jetmaster brings us new versions for
> the oddball fuels entering the market. That process of limiting air to
> high velocity jets is exactly what I found worked well in retaining a
> gas production zone at the bottom of the Vesto. That is why there are
> three 8mm holes near the bottom, instead of plain walls. I found that it
> is far less susceptible to flame-out in the gas burning zone immediately
> above the gas-producing zone.
> Personally I find it much better than the 'pure' pyrolysis approach
> where there is an advancing flame front for the reason that it works
> with wood instead of processed wood and chips and pellets. Even then,
> with homogenised fuels, it is better to have a couple of jets blowing
> onto the surface to keep a flame going immediately above: more reliable
> over wider fuel types.
> The idea of the air jets is that they can reach to the far side of the
> combustion chamber (observe and modify diameter to suit) and there
> should be enough of them so that some can be blocked by fuel and it will
> still work.
> What I saw in the patent drawings looks like a semi-gasifier, in the
> same combustion class as the Vesto and for similar reasons. Both are
> refuellable.
> Regards
> Crispin

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