[Stoves] flue after burn

Crispin Pemberton-Pigott crispinpigott at gmail.com
Mon May 14 08:37:58 PDT 2012

Dear AJ

I had a look at this thing to see if there is a way to validate the claims.

This cannot be factually correct:

"Any smoke or particulate matter not burned in the firebox is compressed and
re-combusted within the cyclone chamber. This is optimised by both the cold
air intakes above and below the cowl. Once the cyclone establishes, the fire
is largely soot and smoke free."

In order for any stove to benefit from increased draft (which is the basic
function they are claiming) it would have to be applied to a stove that
lacked draft. It there was any fire actually taking place in the top of the
chimney (which seems really unlikely) it would probably be illegal.

If it is only acting like a choke at the top of the chimney (which looks
likely) is it reducing fuel consumption or delivering more heat from the
existing fuel? If it is slowing the burn it is doing so by reducing the
amount of draft, not increasing it. As both claims are made - that it is
increasing draft and that it is reducing the amount of fuel used - then one
of them excludes the other for probably 99% of stoves. Burns faster +
reduces fuel consumption and reduces the burn rate and increases efficiency
and burns the particle at the top of the chimney pushing that heat into the

Reducing smoke emissions might be no more than diluting it with more air so
it can't be seen. That seems unlikely though, as the burn time is claimed to
be 1.5 times longer. There is no additional heat from the two logs they
burned, they just burned it slower with the device attached, and the test
result says they were allowed to control the dampers differently for the two
tests, which means the device may have had no impact at all. There is
nothing in the device that created additional draft, is there? A tiny bit
more vertical height? There is certainly no combustion of particulates going
on at the top, as claimed.

The absence of numbers indicating a reduction in smoke is a bit odd. If it
reduced smoke there would be a happy announcement of a measurement before
and afterwards. It seems they think an increase in burn time is an increase
in efficiency, without stating what the efficiency is for the stove with or
without the cowl. 

The patent number claimed 09798186.4 is invalid according to

As the physics, function, efficiency and intellectual property are all
questionable, so is its value.

Crispin waking up to summer in Waterloo


Hi All

It seems a bit quiet here.

Now this may be a little off topic for cook stoves but I was passed this for


It all seems a bit improbable unless there is some sort of catalyst in the
device but even then it must represent a waste of fuel.

The video of it working is shown atop a clay chimney pot that already has
some air entry holes, presumably to prevent back draught in windy

Also note the colour of the smoke, it's black initially, suggesting just
adding a bit of secondary air at the fire would have done the job.


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