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kiln stacks and ventillation

updated fri 31 jan 97

 

Jonathan Kaplan on mon 13 jan 97

Just to add a small thing here...

Many kilns now using forced air have very short stacks that just go to the
top of the arch or so...reference some of the commercial gas downdraft
kilns as these are not dependant on the natural pull from a tall chimney.

My new car kiln is designed in such a way. On top of the stack is a
collection hood that entrains room air into the exhaust. The then vents
into a stainless Metalbestos system that exits the building through triple
wall stainless to the roof. It works very well and quite efficiently as the
stack drafts at low temperatures. We have adequate make up air into the
kiln area.

I remember at RISD during my undergrad years that the kilns all vented into
a massive horizontal collection plenum at then up to the roof where there
was an inline axial fan intorducing a forced draft condition that worked
quite well.

Jonathan


Jonathan Kaplan
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(aka "Scooter)
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Gavin Stairs on tue 14 jan 97

>Many kilns now using forced air have very short stacks that just go to the
>top of the arch or so...reference some of the commercial gas downdraft
>kilns as these are not dependant on the natural pull from a tall chimney.

In such an arrangement, beware of venting CO and other flue gases into the
room from an overpressure flue pipe. THIS IS DANGEROUS! You MUST ensure
that the flue is at VACUUM pressure with respect to the enclosed room. That
goes for the kiln itself, as well. Needless to say, the kiln room should be
adequately vented. A stack fan, or a tall stack will do this, but I suppose
that the fan must be relatively far from the kiln, and certainly heat
resistant along the lines of other posts. The designer must also be aware
that pottery kiln flue gases are often reducing and flammable, and may
introduce a heat load when air is induced into the flow.

Whatever you do with your flue, note that it will change the firing
behaviour of your kiln. You will have to relearn it, and you should have
sufficient dampers and vents to tune the system so it does what you want.

Bye, Gavin

Margaret Arial on fri 24 jan 97

you have a car kiln did you build it - or buy it how is the bottom of the
kiln designed to receive the burners and not melt the track assembly?