Hank Ray on mon 6 jul 98
hello all....
though i can follow a firing schedule, and read the firing suggestions from
the alpine kiln book.... i can't get a "mental" picture of how a updraft
works.... i have looked at the little pictures in books with there arrows
showing the flow of fire..... but it just aint clickin' in my mind..... a
down draft i can picture... even though i have never seen one fired.... but
the updraft ???? how does it get heat to the ware in the middle?
why would the bottom hole be sucking while the top is blowing.....?????
if any of you can enlighten me with a little bit of theory..... that would be
great....
peace...
Hank......
Grimmer on tue 7 jul 98
Hank,
Think of an updraft kiln as a really wide chimney into which
one may load pots. The heated gasses of combustion rise
throught the kiln and exit through the flue in the top. In
general heat transfers from areas of greater heat (over the
burners) to areas of lesser heat (the pots and shelves)
through radiation, convection, and conduction, so it tends to
work out in the end. And you are correct: sometimes the pots
in the middle don't get the same heat treatment as the ones on
the outside. One of the reasons for the popularity of
downdraft kilns.
steve grimmer
marion illinois
Hank Ray wrote:
>
> ----------------------------Original message----------------------------
> hello all....
>
> though i can follow a firing schedule, and read the firing suggestions from
> the alpine kiln book.... i can't get a "mental" picture of how a updraft
> works.... i have looked at the little pictures in books with there arrows
> showing the flow of fire..... but it just aint clickin' in my mind..... a
> down draft i can picture... even though i have never seen one fired.... but
> the updraft ???? how does it get heat to the ware in the middle?
> why would the bottom hole be sucking while the top is blowing.....?????
>
> if any of you can enlighten me with a little bit of theory..... that would be
> great....
>
> peace...
> Hank......
Mike Gordon on tue 7 jul 98
Hi,
If you shut the damper down till flames come out of the peep holes you
are filling the inside of the kiln with flame. Thus it goes everywhere,
even to the middle.Then adjust the gas to keep a bluish orange flame out
the top so you still have temp increase. Any help? Mike
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