Nils Lou on thu 6 oct 11
For a downdraft kiln the best exit flue size will be the one that maximizes
heat retention while balancing the heated gas pressures escaping with
the ones entering, i.e., burner flame. If you have a double Venturi system
the exit flue that experientially I have found best is 32 to 40 square inch=
=3D
es.
exiting into an expanded flue box with its own exit flue into the chimney
matching the first one. It doesn't matter what the kiln volume is; it can b=
=3D
e
12 cubes or 200 cubes.
The relatively small exit flues cause a nice turbulence while speeding up t=
=3D
he
flow of gas exiting via the Venturi effect. The second Venturi lets the gas=
=3D
flow
equally into the expanded space of the chimney. This system adapts automati=
=3D
cally
to any size kiln.
Larger exit flues can work efficiently by well designed coupling to a corre=
=3D
ct
stack height and diameter. Usually with passive dampers speeding up or slow=
=3D
ing
down the exhaust flow.
nils lou
prof. of art
linfield college
http://nilslou.blogspot.com
douglas fur on tue 11 oct 11
Nils
You use the expression "well designed coupling to a correct
stack height and diameter." How do you go about designing those dimensions=
.
DRB
Seola Creek
On Thu, Oct 6, 2011 at 1:59 PM, Nils Lou wrote:
> For a downdraft kiln the best exit flue size will be the one that maximiz=
es
> heat retention while balancing the heated gas pressures escaping with
> the ones entering, i.e., burner flame. If you have a double Venturi syste=
m
> the exit flue that experientially I have found best is 32 to 40 square
> inches.
> exiting into an expanded flue box with its own exit flue into the chimne=
y
> matching the first one. It doesn't matter what the kiln volume is; it can
> be
> 12 cubes or 200 cubes.
> The relatively small exit flues cause a nice turbulence while speeding up
> the
> flow of gas exiting via the Venturi effect. The second Venturi lets the g=
as
> flow
> equally into the expanded space of the chimney. This system adapts
> automatically
> to any size kiln.
> Larger exit flues can work efficiently by well designed coupling to a
> correct
> stack height and diameter. Usually with passive dampers speeding up or
> slowing
> down the exhaust flow.
>
>
> nils lou
> prof. of art
> linfield college
> http://nilslou.blogspot.com
>
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