tunnel klin کوره تونلی

Tunnel Brick Kiln

From Wikipedia, the free encyclopedia

The tunnel kiln is a type of the kilns used in various branches of the ceramic industry. The first tunnel kiln was invented in the year 1751 by a person named Vincennes and is currently used in the brick, pottery, refractory, and Chinese industries. This type of klin is in the category of continuous klins.

Tunnel Kiln Structure

The tunnel kiln is a long, narrow tunnel, that the floor of it has been rails, and the products pass through the heat and are cooked or sintered. Products must be mounted on special wagons to cross the tunnel kiln. The tunnel kiln consists of three stages of preheating, firing and cooling. In the simplest type of tunnel kiln, burners in the firing area will heat the klin air.

The air moves slowly toward the inlet of the tunnel (preheating). Transferring its heat to the wagons in this area, and finally leaving the exust. On the other hand, fresh air enters the tunnel outlet and cools slowly in the wagons passing the firing stage. Then gradually increasing the temperature to reach the firing area and providing the oxygen needed to burn the burners in the area. Of course, some of the heated air is directed out of the klin to be used in the dryer and sometimes to adjust the temperature of the production hall.

Typically, 60% of the klin length is firing area, 20% is preheating area and 20% is the cooling zone. The temperature of various klin zones is measured and adjusted through a thermocouple and control systems. The air inside the klin can be controlled in terms of oxidized, alkaline or neutral.

Benefits of Tunnel Kiln

The use of tunnel kilns compared to other types of kilns (traditional, Hoffman and alternating kilns) has some advantages, some of which can be described as follows:

  • Better control of kiln temperature and heat uniformity
  • Increase production quality
  • The qualitative similarity of products
  • Increase production speed
  • Reduce workers
  • Reducing energy consumption
  • Reducing the harmful effects of the environment

Usage of tunnel kiln in brick industries

Tunnel kiln is one of the most advanced types of kilns used in the brick industries. Raw bricks, which have already passed through the tunnel dryer and lost most of their water, enter the preheating zone and heat up to 350 degrees Celsius. The bricks then enter the firing area and depending on the type of raw material, are burned at a temperature of between 800 and 1100 ° C.

Disadvantages

In the old technology due to the use of refractory bricks, the klin could not be easily switched off and on. It took you about 20 days to warm up this type of klin. In this type of kiln it is not possible to repair the walls without turning it off. On the other hand, due to the chain-linking of the parts, the roofs of the arches may fall off if a part falls down. But today, with the use of newer refractory materials as well as more advanced roofing techniques and the use of flat roofs, these problems have been completely resolved in new tunnel kilns.