Earl Krueger on sun 25 apr 04
Recently several people suggested I consider using
forced air burners for a downdraft kiln. If I did, what
would be the _primary_ method of controlling the
oxidation/reduction level;
flue damper, or
shutter on air intake to the burner fan, or
fuel flow?
(Assume there is not a tall chimney inducing draft.)
This is not at all clear to me. Guess I gotta build
one so I can test..test..test...
Earl K...
Bothell, WA, USA
Dave Finkelnburg on sun 25 apr 04
Earl,
While gas flow will affect reduction/oxidation, you really use it to
control rate of temperature rise in a kiln. With that fixed, air flow
control determines the firing atmosphere.
IF you have an open burner port, you will use both the damper and the
fan damper to control air flow to the burner. Both are critical...it's
almost impossible to say one is primary. With my kiln, when I open the fan
dampers, I also open the flue damper, and vice versa. Only if you used a
closed burner port (common in industry, not common in studio kilns) would
you be able to control the air flow entirely with the fan damper.
If you had an Oxyprobe you could really see how the two adjustments work
together.
Dave Finkelnburg
----- Original Message -----
From: "Earl Krueger"
Sent: Sunday, April 25, 2004 10:22 AM
> Recently several people suggested I consider using
> forced air burners for a downdraft kiln. If I did, what
> would be the _primary_ method of controlling the
> oxidation/reduction level;
> flue damper, or
> shutter on air intake to the burner fan, or
> fuel flow?
Des & Jan Howard on mon 26 apr 04
Earl
On our forced air burner LPG kiln:
No chimney - damper slide sits on top of refractory casting in middle of kiln roof.
Burners are not sealed into burner blocks - burners go up to, but, not into
blocks, minimal gap around burners ~5 mm.
Blower (550 mm D x 60 mm) has a round biscuit tin sealed to its
air intake, a wooden disk sealed to the base of the tin & a concentric
slot cut into the disk, a plastic slide over the slot allows for very small adjustments.
Fuel flow, air intake & damper are all used as control methods.
Each is tweaked according to established procedures during a firing.
Des
Earl Krueger wrote:
> Recently several people suggested I consider using
> forced air burners for a downdraft kiln. If I did, what
> would be the _primary_ method of controlling the
> oxidation/reduction level;
> flue damper, or
> shutter on air intake to the burner fan, or
> fuel flow?
>
> (Assume there is not a tall chimney inducing draft.)
--
Des & Jan Howard
Lue Pottery
LUE NSW 2850
Australia
Ph/Fax 02 6373 6419
http://www.luepottery.hwy.com.au
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