TL;DR
Excessive tire ovality flexes the kiln shell and cracks the refractory. Measure the tire stop position and the tire-to-shell gap, then adjust the tire position to correct ovality.
What you might see
- periodic knocking noise from tire area
- measured tire ovality above tolerance
- refractory brick cracking near tire position
- girth gear vibration correlated to kiln rotation
Likely causes
Loose tire fit on the shell allowing excessive migration and tire-shell gap increase
Shell temperature distortion from refractory damage creating local hot spots
Tire fillet pad wear reducing the contact bearing surface
Incorrect tire positioning during initial installation
Required tools
- IR thermometer
- Feeler gauge set
- Chalk or paint for marking
- Tape measure
- LOTO kit
Safety first
- Kiln shell surface remains extremely hot after a stop. Use IR thermometer before approaching and use thermal gloves.
- The kiln tire weighs several tonnes and could shift if the shell moves. Lock out all drives before any measurement near the tire.
- Thermal radiation from the kiln shell. Use radiant-heat PPE.
Procedure
- 1
Stop the kiln and cool it. Lock out all kiln drives.
Warning: Rotary kiln shells retain extreme heat. Allow adequate cooling before approaching the tire area and verify surface temperature with an IR thermometer. - 2
Measure the tire stop position (creep) by marking the tire and shell during a slow-speed rotation and measuring the relative offset after one full revolution.[1]
- 3
Measure the tire-to-shell pad gap at multiple points around the circumference using feeler gauges.[1]
- 4
Measure the tire outside diameter at several points to quantify the ovality.
- 5
If the tire stop exceeds the specification, consult the kiln documentation for the tire pad adjustment or replacement procedure.
- 6
Inspect refractory brickwork in the tire zone for cracking or loosening from the flexing action.
- 7
Report the measurements to a kiln alignment specialist. Tire correction often requires a planned full-length kiln alignment check.
Sources
FLSmidth FLSmidth ROTAX-2 Rotary Kiln general technical documentation, FLSmidth
FLSmidth ROTAX-2 rotary kiln maintenance documentation, tire and shell ovality inspection procedures (general)
More guides for FLSmidth FLSmidth ROTAX-2
How to detect and respond to refractory brick failure on a FLSmidth ROTAX-2 rotary kiln
A hot spot on the kiln shell means the refractory brick has failed in that zone. Stop the kiln immediately if the shell temperature exceeds the maximum safe value to prevent shell distortion.
How to detect and correct kiln thrust roller misalignment on a FLSmidth ROTAX-2
Excessive axial kiln migration means the support rollers are not skewed correctly to control axial float. Adjust the roller skew angle in small increments and monitor migration response.
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