On 21 Apr 2003 at 10:07, Alan Riach wrote:
 hotter "oven" of combusted
> material will be maintained in the smoker ensuring that it stays lit
> much better.
Hi all

The main purpose of a smoker is to produce smoke-and that is
an objective that the  vast majority of general combustion work
is aiming to prevent.  This suggests that changes designed to
make a smoker burn better or hotter may be running counter to
what is required.

A smoker needs to burn in a such a way that, when additional
air is supplied through the bellows, the resulting combustion is
relatively poor-judged by normal combustion standards-
liberating unburnt carbon particles in the outgoing airflow to
form the smoke.  This suggests that perhaps a low temperature,
smouldering type of combustion is required, rather than a hot,
burning fire.  It may be why a shredded and closely packed
smoker fuel, with a great deal of surface area combusting at the
same time, works better.

There appear to be some similarities with a cigarette
combustion.  In the unblown situation the cigarette smoulders
very slowly, but when a draft is applied, smoke and other
chemicals are liberated for a short duration, after which the
slow smouldering is resumed almost immediately.

Perhaps we need to take up James Fisher's proposal to design a
better smoker from scratch, based on sound physical principles.
My own limited experience of combustion suggests that this
may be a difficult activity-especially if a wide range of materials
is to be burnt.

On a related note, the analogy with cigarette combustion
makes me wonder if beekeepers should be concerned about the
possible effects of smoker-produced smoke on their health.  I
am pretty sure that smoke from most cellulose based fuels will
contain many of the unpleasant chemicals in tobacco smokes
that are accused of causing damage to health.

Mike Rowbottom


HARROGATE
North Yorks
UK

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