Civil Engineering Reference
In-Depth Information
Figure 8.10: Firing clay blocks that in themselves form the walls of the kiln.
Source: Khalili 1983
There is a hole in the roof and an air duct in the ground to feed the fire. A thick
layer of earth is placed over the whole building and a huge bonfire is then lit
inside the building. A door or hole in the roof is required so that the fire can be
loaded with wood. After a couple of days, firing is complete. The building then
needs a couple of days to cool down. The earth is removed, the windows are
knocked out and any cracks in the walls are filled.
The Hoffman kiln, unlike the charcoal kiln that has to be cooled after each fir-
ing, can be kept in continuous use. The firing zone can be simply moved from
chamber to chamber. Each chamber is firing for a set period before the heat
moves onto the next chamber. A complete rotation takes about three weeks. The
bricks are fired with sawdust or fine coal-dust sprinkled down through small
openings in the roof of the chambers. In modern brickworks where circular kilns
are still used, it is more usual to use oil as a fuel.
Search WWH ::




Custom Search