Lois on fri 22 oct 04
I have a 40 cu ft downdraft natural gas kiln with Ward power burners
(yes, Mel I built it myself:) I have no trouble firing or getting great
reduction. Just trying to understand.
I want to know more about the response to air.
I understand by opening fan flaps and adding air it increases the temp rise,
(like blowing on coals)
But what does the fan do? I know it increases the speed the air moves
through the kiln. The air only has one way out, so the extra speed does
what?
Cause more turbulence? Does this help even out, front to back and top to
bottom? Does it cause the temp to rise faster or slower by pushing the heat
out faster?
Can someone explain the mechanics of fire and air speed?
Wanting to understand a little more......
Lois Sharpe
Durham NC
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Snail Scott on sat 23 oct 04
At 12:18 PM 10/22/2004 -0400, you wrote:
>...But what does the fan do?...
>Cause more turbulence? Does this help even out, front to back and top to
>bottom? Does it cause the temp to rise faster or slower by pushing the heat
>out faster?
Forced-air burners do several things that aren't
within the repertoire of a venturi burner. One
is that it creates more pressure inside the kiln,
making the kiln less dependent on chimney height.
A forced-air kiln can even be a downdraft with no
chimney at all. Turbulence is another factor. It
can make it easier to move the heat around by
manipulating the airflow. 'Pushing heat through
faster' isn't what we want, but a good draft is
necessary to good combustion.
-Snail
Graeme Anderson on sun 24 oct 04
I think the use of a fan behind the burner increases the amount of air, and
therefore oxygen, going into the kiln for the gas to burn more efficiently,
and decrease the amount of reduction. I have done this occasionally with
an 8 cu. ft. gas kiln, with one burner.
Cheers. Graeme.
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