Types of Brick Furnaces.

Burnt S A Bricks

INTRODUCTION
Brick furnaces also known as brick kilns are used to bake or burn clay products, they have been used for long period of time to produce ceramic products, bricks and tiles. They usually constructed outside a wide area of flat lands. They are circular, oval or rectangular in shapes and normally use firewood as fuel to harden up products inside.

Characteristics of a good brick furnace is that the bricks must be strong enough to withstand the heating and cooling process. They must be quite easy to build. They must be sturdy and strong enough to withstand the loading and unloading of products. They must not be affected by any change in weather and be for a long time. They must be built in such a way that they allow in air to aid in fueling and prevent entry of air at intervals.

The type of brick to be used for brick furnace construction is very vital, they have to be porous, a good insulator and a great thermal shock resistance and heat control. The sizes of brick furnace differs, some houses ledges inside where the products are lined for burning. Burning in brick furnace is a skill which requires a great experiment in order to produce perfect products.

TYPES AND CHARACTERISTICS OF BRICK FURNACES
The Bull’s Trench Kiln: this is mainly for firing up green bricks; the kiln is circular in shape made by digging a trench on a dry land. It is about 6-9m wide, 2-3m deep and 100-150m long with a movable chimney. The products to be fired are placed in rows of twos or threes bricks apart with openings in-between to allow fueling and air passage.
A connecting set of bricks is built across the width of the kiln and halfway up to steady the kiln. The top is settings of two bricks covered with brick dust. A large canvas is placed upright across the brick setting to prevent air from coming in from the wrong side of the chimneys. The trench can house up to 200-300 fired products at a time.

The Vertical Shaft Brick Kiln: this kiln was first developed in china to curb the problem of need for good quality bricks as a building material for houses. This type of kiln does not make use of firewood as fuel but a small amount is needed to fire up the kiln first. It mainly burns on coal dust as fuel. It is a kiln that can continuously burn for 24 hours. It is quite similar to Tunnel kiln but the bricks in this case move from top to the bottom of the vertical shaft. It advantages includes- the coal for fuel does not emit smoke but burns smoothly, the kiln can be operated even during rainy season, it has a low operating cost and does not require a full-fledged skilled operator to work it so far adequate training is provided.

The Tunnel Kiln: is a type of kiln that is mobile-ware kiln whereby the products to be heated are placed on carts through a long straight tunnel. Air is drawn from where the cart exits at the end of the kiln to cool the products. The firing process takes place at the center part of the tunnel. It is a modernized brick making system. The advantage includes its ability to heat up a great number of products, a great level of control over the firing process and produces products of great quality.

The Missouri Kiln: this is a kiln built in such a way that it gives access to mechanical objects like trucks and tractors for loading and unloading of the kiln in an effortless and quick method. The volume size ranges from 4m to 350m. It is not constructed to be too large for easy control. It is rectangular in shape, 7m wide and 11m long with the walls 250mm thick. The kiln is constructed to be adaptive to harsh weather.

The Beehive Kiln: they are circular in shapes with a roof shaped like a dome and constructed with ordinary bricks. The circular wall is in complete connection with the outside air. The advantages of this type of kiln is that they are quite easy to construct, they requires simple materials of few bricks, one steel for the dome top and no concrete foundation required, the life span is up to 6 years when it is on one site and the bricks can be dismantled with minimal loss and used again on another site, it gives even cooling to products because the walls are completely connected with the outside air, it is cheap and easy to maintain with little repair and no cracked walls.