Introduction to Tunnel Kilns:
A tunnel kiln is a continuous firing device widely used in the
ceramics, brick, and glass industries. It is named for its unique
elongated structure and continuous production method.
The design of a tunnel kiln allows green bricks or other ceramic
products to move slowly through the kiln, passing through different
temperature zones to complete the firing process.
Structure of Tunnel Kilns:
1. A tunnel kiln typically consists of the following main parts:
(1) The main structural part of the tunnel kiln, usually an
elongated passage with tracks or rollers inside to support and move
the green bricks.
(2) The first zone that the green bricks enter after entering the
kiln body, where the temperature gradually increases to remove
moisture from the bricks.
2. Firing Zone: The core area of the tunnel kiln, with the highest temperature,
where the bricks are sintered.
3. Cooling Zone: The zone where the fired bricks are cooled down gradually to a
temperature suitable for unloading.
4. Combustion System: Provides the heat required for firing, usually including burners,
fuel supply systems, and exhaust systems.
5. Ventilation System: Controls the airflow inside the kiln to ensure complete combustion
and uniform temperature distribution.
6. Drive System: Used to move the green bricks through the kiln, usually including
motors, chain drives, or roller drive devices.
Working Principle of Tunnel Kilns:
1. The working principle of a tunnel kiln is based on a continuous
production mode.
2. Green bricks are placed on kiln cars, which enter the kiln body
via tracks or rollers.
3. The green bricks are gradually heated in the preheating zone to
remove excess moisture, and the exhaust gases from the kiln can be
recirculated to improve thermal efficiency.
4. The green bricks reach the highest temperature in the firing
zone and complete the sintering process.
5. The fired bricks are gradually cooled in the cooling zone to a
temperature suitable for unloading.
6. Kiln cars move continuously through the kiln, with new green
bricks entering and fired bricks being unloaded, achieving
continuous production.
Advantages of Tunnel Kilns:
Tunnel kilns have the following advantages:
1. Continuous production: Capable of large-scale continuous
production, improving production efficiency.
2. High thermal efficiency: Heat recovery in the preheating and
cooling zones improves thermal energy utilization.
3. Stable temperature control: Precise control of the temperature
distribution inside the kiln ensures consistent product quality.
4. High degree of automation: Can be equipped with automated
control systems to reduce manual intervention and improve
production stability.
5. Wide application range: Suitable for firing a variety of ceramic
products and bricks, with strong adaptability.
Applications of Tunnel Kilns:
Tunnel kilns are widely used in the following fields:
1. Ceramics industry: For firing ceramic products such as tiles and
sanitary ware.
2. Brick and tile industry: For firing clay bricks, cement bricks,
etc.
3. Glass industry: For firing and annealing glass products.
4. Refractory materials industry: For firing refractory bricks and
other refractory materials.
Maintenance and Care of Tunnel Kilns:
To ensure the efficient operation and long service life of tunnel
kilns, regular maintenance and care are necessary:
1. Regularly inspect the kiln body for cracks, deformations, or
other damage, and repair them in a timely manner.
2. Clean the combustion system regularly, including burners and
fuel supply systems, to ensure complete combustion.
3. Ensure that the ventilation ducts are unobstructed and check the
normal operation of fans.
4. Inspect the operation of the drive system, including motors,
chains, or roller drives, and lubricate and replace worn parts in a
timely manner.
5. Regularly calibrate temperature sensors and control systems to
ensure accurate temperature control.
