TL;DR

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.

What you might see

kiln migrating axially beyond normal limits
tire flange contacting thrust roller flange
thrust roller bearing temperature elevated
one support station carrying more load than others

Likely causes

Tap to mark as ruled out

Support roller skew angle drifted from the design value during thermal cycling
Thrust roller bearing failure allowing uncontrolled axial movement
Uneven support station loading from a settling foundation causing the kiln axis to deflect
Excessive tire migration from loose tire fit amplifying the axial load on the thrust roller

Required tools

Precision level
IR thermometer
Bearing housing adjustment tools

Safety first

Never stand under the kiln tire or between the tire and support roller while the kiln is rotating.
Extreme thermal radiation from the kiln shell. Use radiant-heat PPE and maintain safe distance.

Procedure

6 steps · ~60 min

1
Record the kiln axial position from the position indicator over several days to establish the migration trend and rate.[1]
2
Measure the roller skew angle at each riding roller station using a precision level or the survey marks on the support frame.[1]
3
If the skew angle at one station deviates from the design value, adjust the roller bearing housing laterally in small increments (0.5 mm at a time) and observe the migration response.
4
Check the thrust roller bearing temperature with an IR thermometer during operation.
5
Inspect the contact face of the thrust roller and the tire flange for wear marks indicating active metal contact.
6
Contact a kiln alignment specialist if the migration rate exceeds the allowable limit or if multiple stations require adjustment simultaneously.

Sources

FLSmidth FLSmidth ROTAX-2 Rotary Kiln general technical documentation, FLSmidth
FLSmidth rotary kiln alignment and support station maintenance documentation (general)

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