[Stoves] Crispin´s kiln

[Tom Miles]

Peter,

That's a fun design. It's really more of a downdraft staged combustor. I've
worked with Russian and Japanese designs which burn chips that are very
similar. They can make a lot of removable char. I doubt that it could
maintain the 1100-1300C temperature required. I noted the comment about the
4 cone difference in temperature along the back will for the 100 ft3 kiln.
Crispin's requirement is for high temperature and uniform temperature
control. 

Kiln builders like Joe Finch
(http://www.amazon.com/Kiln-Construction-Brick-Approach/dp/0812219848 )
suggest that a kiln built to fire up 1150 C is a lot different than one
designed for 1300C. (In "pros and cons" he lists an advantage for wood
firing as: "Wood firing can satisfy one's pyromaniac tendencies!")    

Tom


-----Original Message-----
From: stoves-bounces at listserv.repp.org
[mailto:stoves-bounces at listserv.repp.org] On Behalf Of Peter Singfield
Sent: Thursday, July 05, 2007 6:19 PM
To: stoves at listserv.repp.org
Subject: Re: [Stoves] Crispin´s kiln


OK -- 

"Side Stroke" is a 

"Site for woodfire potters"

http://www.sidestoke.com/index.html

Much material be there!!

But what should be of interest is:

http://www.sidestoke.com/bourrybox/bourrybox.html

Check out the diagram.

The Bourry Box was designed by French ceramic industrialist Emile Bourry and
first described in his book "Traite des Industries Ceramiques" in 1897.
An English translation 'A Treatise of Ceramic Industries: A Complete Manual
for Pottery, Tile and Brick Manufacturers' was available from 1901. In a
Bourry Box kiln, the flames are pulled down by the kiln draft, so the fire
burns 'upside down'.

Your looking at 110 year old design -- Bottom lit down draft gasifier
specifically for firing a pottery kiln.

This might just be the answer??

Lot's more at the main site.

Peter/Belize

************appended text************

The bourry firebox works on the downdraft principle. The flames are pulled
down by the draft of the kiln, rather than rising as they do in an open
fire, so the fire burns upside down. In the diagram, logs at the bottom of
the stack have burned for the longest time, and fall onto the bed of embers
when they can no longer support themselves. New wood is added to the top of
the stack through the firebox door (coloured dark blue).

Air for combustion enters through the woodpile (primary air) and the
secondary air is adjusted to maintain the right proportion of air and fuel
for the oxidising, neutral or reducing kiln atmosphere required. The purpose
of the mousehole air is to keep the embers burning. If stoking is too
enthusiastic or the embers stop burning properly the entrance to the kiln
chamber will quickly clog up and the firebox will cease to operate
efficiently.

At the start of a firing a small fire is started on the floor of the ashpit,
where the embers later build up. When this fire is big enough, usually when
the temperature is in the 350 to 400 degrees C range, logs are introduced
across the hobs. After a transition period, the firebox starts to operate
properly, and all stoking is onto the hobs.