Brictec Summarizes Systematic Tunnel Kiln Maintenance System 
Based on Brick Plant EPC Project Management Experience and Actual Operation

The maintenance of a tunnel kiln in a clay fired brick plant is by no means limited to kiln cars, fans, burners, high-temperature bearings, etc. In fact, it is a comprehensive maintenance system integrating a complete thermal system, a mechanical maintenance system, and an automatic control system.
Systematic maintenance in the daily operation and management of a brick plant is the guarantee of normal production. Based on years of brick plant EPC project experience and observations, Brictec has found that many brick plants lack systematic daily maintenance standards and inspection checklists. Brictec has now compiled the core tunnel kiln maintenance system for reference.

I. Overview of the Tunnel Kiln Core Maintenance System
Tunnel kiln maintenance can be divided into six major systems:

1. Kiln Structure System
2. Combustion System (Burners)
3. Ventilation and Thermal System
4. Transmission and Transport System
5. Automatic Control System
6. Auxiliary Heat Utilization System (Drying Chamber, etc.)

II. Kiln Structure System (Most Easily Overlooked, but Most Critical)

1. Kiln Lining Refractory Materials
Key inspection points: Refractory brick falling off / cracking, insulation layer pulverization, arch crown sagging, expansion joint failure.
Common problems: Air leakage, increased heat loss.

2. Kiln Steel Structure
Inspection items: Steel structure deformation, weld cracking, proper thermal expansion compensation.

3. Kiln Door System (Kiln Head / Kiln Tail)
Key points: Sealing performance (very critical), air leakage condition, smooth operation of opening/closing mechanism.

III. Combustion System (Core)

1. Burner (Natural Gas / Heavy Oil / Pulverized Coal)
Maintenance focus: Nozzle carbon deposition / clogging, stable flame shape, normal ignition system.
Common problems: Flame deflection, excessively long/short flame, local overburning or underburning.

2. Fuel Supply System
Natural gas system: Pressure reducing valve, flow meter, pipeline sealing.
Heavy oil system: Heating system, filtration system, injection pressure.

IV. Ventilation and Thermal System (Determines Firing Quality)

1. Induced Draft Fan / Exhaust Fan
Inspection: Air flow stability, impeller dust accumulation, vibration.

2. Kiln Pressure System
Key control: Stable micro-negative pressure, preventing cold air backflow.

3. Air Duct System
Inspection: Blockage, air leakage, dust accumulation.

4. Temperature Measurement System
Includes: Thermocouples, temperature controllers.
Problems: Temperature drift, measurement point distortion.

V. Transmission and Transport System

1. Pusher / Puller
Inspection: Thrust stability, stroke control, chain wear.

2. Rail System
Key points: Rail levelness, gauge, local settlement.

3. Kiln Car Sealing System
Inspection: Kiln car sand seal, sealing plate.

VI. Automatic Control System (Core of Modern Brick Plants)

1. PLC Control System
Inspection: Program stability, signal feedback.

2. Sensor System
Includes: Temperature, pressure, flow.
Problem: Error accumulation → firing curve out of control.

3. Actuators
Examples: Electric valves, damper actuators.
Inspection: Response speed, accuracy.

VII. Drying System (Strongly Correlated)
Maintenance includes: Drying fans, hot air pipes, humidity control.

VIII. Easily Overlooked but Very Critical Points (Summary of Experience)

1. Air Leakage Management (Top Priority)
The biggest hidden dangers of a tunnel kiln: Kiln door, kiln car, kiln body cracks.

2. Temperature Curve Consistency
Not just "temperature is high enough", but: whether the curve is stable + whether it is repeatable.

3. Combustion Uniformity
Determines: Brick color, strength, cracks.