The "Breathing System" of a Tunnel Kiln Revealed
A red brick tunnel kiln is like a breathing behemoth, relying on fans to maintain its "body temperature" and "breathing rhythm." There are three main types of fans inside the kiln:
Exhaust Fans: Like the "lung capacity provider," responsible for expelling waste gases generated during firing and controlling the negative pressure inside the kiln.
Combustion Fans: Like the "oxygen transporter," providing sufficient air to the flames and affecting combustion efficiency.
Cooling Fans: Acting as "thermometers," controlling the temperature of the bricks exiting the kiln and preventing rapid cooling and cracking. When production needs to be increased, it's like accelerating the breathing of a runner; you must first identify which "respiratory organ" to adjust.
Which "breathing switch" should be activated when increasing production?
The core of increasing production is improving combustion efficiency, which requires adjusting two key fans simultaneously:
Prioritize adjusting the combustion fan: Increase the airflow by 10%-15% (depending on kiln conditions) to ensure more complete fuel combustion. Just like increasing the air intake of a stove makes the flames stronger.
Synchronous adjustment of the exhaust fan: Maintain the negative pressure inside the kiln at -15~-25Pa (empirical value) to prevent backflow of exhaust gases. Like adjusting the airflow of a range hood, it needs to exhaust quickly without sucking away the flames.
Special Note: Cooling fans usually do not need adjustment unless the bricks exiting the kiln are too hot.
The "Golden Rules" for Adjusting Fans: Remember three principles in actual operation:
Small, Slow Adjustments: Adjust no more than 5% at a time, observe for 2-3 hours before deciding whether to continue.
Temperature Monitoring: Focus on whether the firing zone temperature is stable at 950-1050℃ (ideal firing temperature for red bricks).
Energy Consumption Balance: Excessive increase in combustion airflow will lead to increased heat loss from exhaust, thus reducing thermal efficiency. Some brick factories have blindly increased combustion airflow, resulting in bricks with a "black core" phenomenon because excessively rapid combustion led to insufficient internal oxidation. Adjusting the fan is like tuning a stereo system; you need to find the most harmonious balance.
