Periodic kiln and continous kiln
Periodic kiln
Before its invention, bricks and tiles were fired in so-called “periodic kilns”. This method was very
time-consuming because it is essential to ensure that ceramic materials are not heated up and cooled
down too fast. This meant that the fire had to be increased very slowly and carefully, and that the baked
bricks had to remain in the oven several days after the fire was extinguished. During this whole period,
the periodic oven could not be used to bake a new stack of bricks. Moreover, the structure itself had to
be heated up every time, and during the firing process most heat was lost through the chimney or the roof,
wasting large amounts of fuel.
Continuous (or Tunnel)
There are two types of continuous kilns:
Tunnel kiln – the bricks are moved through a stationary fire zone, like a train in a tunnel.
Continuous kiln – the bricks remain stationary and the fire moves through the kiln with assistance
or help of a chimney or by a suction fan.
Both types are long structures in which only the central portion is directly heated. The same result can
be achieved with both types of kilns.
The main difference is the tunnel kiln is more expensive to build however it saves on labour costs and
can be highly automated, bricks can be made and burnt without being touched by human hands.