nikom chimnok on mon 24 nov 97
I realize this is a bit out of the realm of CLAYART, but I wonder if anyone
could suggest sources of information on how to build a continous kiln--the
kind with railroad tracks, that runs 24 hours a day.
I am writing from a pottery community in Thailand where in total we use
perhaps 150 wood-fired kilns. The end of this is in sight: no more trees.
Already there are a few 2.5 and 5 cubic meter car kilns fired with gas, but
these are toys, compared to what we normally use. Both their capital cost
and firing cost is outrageous, compared to the wood-burners. I think the
thing to do would be get a jump on the future, build a long kiln or two, and
do all the firing in one place. The energy savings would be tremendous, and
quality would go up too. We already have adjusted our claybody--down from a
48 hour firing to only 16 now.
If anyone has suggestions I would appreciate--especially from Taiwan or
Australia or someplace closer than America.
TIA
Nikom
koratpot@loxinfo.co.th
Gavin Stairs on tue 25 nov 97
Hi Nikom,
I read your message with something like a mixture of horror and hope. I
knew that Thailand was logging and damming everything in sight, but the
idea of there being no wood left... well, it reminds me of what England did
to its forests several hundred years ago. Do we really have to repeat all
the mistakes of our predecessors?
However, the idea of making a continuous kiln is super, if there is enough
ware to keep it going. A continuous kiln can be much more fuel efficient,
because the cost of heating the kiln itself is cut way down, and
reverberatory heating can recover some of the useful heat of the ware
itself as well. Unfortunately, design of these kilns is normally done by
highly skilled engineers who are specialists working for consulting firms.
It isn't beyond possibility to design and build one yourself, but it will
mean getting access to a good library, and learning some furnace design
from the ground up. Perhaps you may find a suitable expert to help you
through some kind of aid outfit like CIDA. Ask around at the embassies of
likely donors like Canada, the US, Australia, NZ, and various European and
Asian countries.
As for the design itself, it can be built very much the way an ordinary
arch kiln is built, or an extended car kiln. The tracks run underneath a
travelling cart which bears the kiln floor on it, so most of the floor
travels with the kiln. The tricky bit is to figure out the burner design,
the length of the kiln and the cross-section. You can build the kiln to
fire almost any schedule you want, but once the burners are set, it will be
difficult to alter the firing to something not planned for initially.
All of this can be done experimentally, if you can afford to reset things
more than once. The role of the expert is to get it right the first time,
and to contribute solutions to problems at the design stage rather than
after disasters. You will probably be recruiting a large segment of the
pottery makers in your community to support this thing, and they will
probably not want to risk several months of firings and income for tuning
and fixing.
I'm afraid that's about all I can contribute at this distance. Good luck
in your venture.
Gavin
stairs@echo-on.net
http://isis.physics.utoronto.ca/
416 530 0419 (home) 416 978 2735 (work)
Toronto, Ontario, Canada
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