Tom King on thu 22 feb 07
Hello People,
Have looked at your conversations on preheating.
Thank you to those responding.
Looks like I am going to have to run with this
one alone. Applicability is going to be somewhat
system dependent. This kiln and burner combo feels
like it is hard to hold back in the early stages.
It is that factor that should lead my decision.
While the performance is satisfactory so far, I feel
like I am walking too near the edge of stressing
the shelves.
I have to admit also, that in my equation, operator
confidence is a factor. I do not want to experience
a costly exceedence there.
Last question. My original post questioned another
post which suggested that (that potter) experienced
a 600 degree difference in temp top to bottom when
they used a preheat burner. Has anyone ever paid
enough attention to this to know whether this normal
for them?
Thanks again,
Tom King
William & Susan Schran User on fri 23 feb 07
On 2/22/07 11:54 PM, "Tom King" wrote:
> Looks like I am going to have to run with this
> one alone. Applicability is going to be somewhat
> system dependent. This kiln and burner combo feels
> like it is hard to hold back in the early stages.
> It is that factor that should lead my decision.
> While the performance is satisfactory so far, I feel
> like I am walking too near the edge of stressing
> the shelves.
Tom,
Can't recall what type of shelves you're using, but cordierite/mullite
shelves can withstand a fair degree of thermal shock.
My small gas updraft gets to 1000=B0F in an hour, shelves are ok, even with
flames right on them.
--=20
William "Bill" Schran
wschran@cox.net
wschran@nvcc.edu
http://www.creativecreekartisans.com
=20
Snail Scott on fri 23 feb 07
At 11:54 PM 2/22/2007 -0500, you wrote:
>...(that potter) experienced
>a 600 degree difference in temp top to bottom when
>they used a preheat burner. Has anyone ever paid
>enough attention to this to know whether this normal
>for them?
Preheat or candling often does not=20
establish a good draw, especially in=20
downdraft designs. So yes, I often=20
see huge temperature discrepancies=20
in fuel kilns during preheat. It can
vary a lot from one kiln to another.=20
The main concern in my mind is to make=20
sure that the bottom (which is usually=20
the cold zone) isn't stone-cold when=20
the real firing starts. I'd like it=20
to be above 200=BAF at least.
-Snail
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