The rotary kiln is one of the most critical pieces of equipment in cement production. It endures significant thermal loads and operates under a continuous production system. This situation demands high standards for equipment quality and operational practices. The operational condition of the rotary kiln directly affects the normal functioning of the entire production process.
Working Principle of the Rotary Kiln
The rotary kiln's body is theoretically inclined at an angle of 3 to 4 degrees on the supporting rollers. The center lines of the rollers must be parallel to the center line of the kiln. As the kiln rotates, its weight creates a downward force, causing a slow descent. The hydraulic thrust rollers help maintain a stable "floating" state, preventing local wear between the roller and the kiln shell. However, in practice, the kiln may experience abnormal movements due to factors like uneven foundation settlement, cylinder bending, equipment wear, and manufacturing errors.
Consequences of Abnormal Movement
Abnormal movements can lead to several negative consequences:
- Temperature Increase: When the axial force on the rollers exceeds a certain limit, the thrust plates apply additional force to the bearing surfaces. This situation causes abnormal friction, leading to temperature increases. High temperatures can damage the oil film, resulting in poor lubrication and increased bearing temperatures.
- Local Wear: Uneven contact surfaces between the rollers and the kiln shell may result in localized wear. This wear can cause vibrations in the rollers and may lead to slower rotation. Increased axial force can cause severe dry friction between the bearing surfaces, leading to temporary stops in the rollers and harmful sliding instead of normal rolling.
- Hydraulic Thrust Roller Overload: Excessive downward force can overload the hydraulic thrust rollers, reducing their lifespan. Conversely, if the upward movement is too fast, it may damage the kiln’s tail seal, leading to serious accidents.
Solutions
To address abnormal movement in the rotary kiln, companies must pay close attention, identify the causes, and make necessary adjustments. Here are some practical strategies:
1. Comprehensive Inspection and Assessment
Begin with thorough inspections to identify which roller experiences the highest axial thrust. You can use the following methods:
- Observe Gaps: Record the gaps between the roller and the guiding iron to determine the axial force direction.
- Record Roller Axial Gaps: Check the gaps between the thrust plates and the bearing surfaces to assess the force on each roller.
- Lead Wire Method: Use lead wire to check contact conditions between rollers and the kiln shell. Compare the width of the pressed lead wire to determine if the roller axes align with the kiln centerline.
2. Adjusting Friction Coefficient
You can apply different lubricants to the roller surfaces to change the friction coefficient. This adjustment can help control the kiln's movement. While this method is quick, it is not a long-term solution.
3. Adjusting Roller Axes
Use various techniques, such as graphical methods or hand signals, to determine the direction of adjustments needed for roller axes. Be cautious to avoid creating an "eight" shape with the rollers, as this can lead to increased torque and wear.
Conclusion
By observing and recording data carefully, you can identify the underlying issues and implement targeted solutions to resolve abnormal movements in the kiln. Regular inspections and maintenance will ensure the rotary kiln remains in a proper "floating" state. This approach reduces failure rates, extends service life, lowers energy consumption, and ensures production efficiency, ultimately achieving significant economic benefits.For further information or professional support, please feel free to contact us. We look forward to providing you with quality services and solutions!
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