A pottery kiln is a device used to heat the pottery until it hardens and is ready for glazing or other decorative work. There are several types of kilns, which are classified by their type of construction. Typical kilns are either updraft or downdraft and sprung-arched or catenary arched.
Updraft
In a domed updraft type, the flame is applied to the floor of the kiln at its center point, where it radiates through the kiln, providing heat to the pot in the main chamber. The exhaust escapes through the top of the kiln at its center point.
Downdraft
In a domed downdraft type, the fire is applied at the bottom of the kiln, but at the right side instead of beneath the kiln. The heat circulates through the main chamber before being funneled through the exhaust passageway that leads from the left-hand bottom of the kiln to the left-hand top where it is released.
Sprung Arch
In constructing a sprung-arched kiln, a form is used to shape the roof. The result is a domed roof located upon straight walls, similar to an upside down U.
Catenary Arch
A catenary arch supports itself, and features a gradual continuous slope. The shape is similar to an upside-down V.
Considerations
Either arch type can be mixed with either updraft or downdraft exhaust types. In selecting the combination, a variety of factors are taken into account, including the type of pottery being fired and the location of the kiln.
