Flame control at different sections is critical during firing in tunnel kilns. Improper heat will compromise product quality and production efficiency. Here, Yonghua Kiln shares practical flame observation skills.

Flame Observation and Adjustment Skills for Tunnel Kilns

Proper flame observation helps promptly tackle problems caused by improper heating.

1. Solutions for Excessively High Temperature

1. Cut down coal dosage in raw materials. For gangue bricks, reduce gangue and add more clay.

2. Speed up the feeding pace, though this may cause large black cores inside bricks.

3. Lower exhaust fan output and adjust feeding speed to reduce firing temperature.

2. Treatment for Low Temperature During Firing

Common causes include insufficient internal fuel, improper damper operation, or complete consumption of internal fuel in the low-temperature zone.

• If low temperature results from insufficient air: Raise dampers gradually to increase air volume. Avoid sudden large adjustments which may put out flames.

• If caused by excessive air: Lower dampers to reduce airflow, or stack bricks at the discharge end to restrict ventilation. Close waste heat dampers in the holding and cooling zone immediately.

3. Handling Overheating in the Firing Zone

The firing zone gets overheated when the brick temperature approaches the upper limit of the sintering range, with the brick color turning from deep yellow to pale yellow. This usually stems from poor flame control or excessive internal coal addition.

Countermeasures:

• Stop adding external coal and monitor flame conditions closely.

• For localized overheating, blow cold air through observation holes with low-volume fans. Strictly control the proportion of internal coal.

For more details, please feel free to contact us.