Roller Press Bearing Temperature Troubleshooting for Cement Plants

Why roller press bearing temperature rises

A cement roller press operates under very high contact loads while the fixed and movable rollers must maintain a controlled gap and stable relative position. KHD’s current roller-press control philosophy emphasizes contact pressure, roller position, gap consistency and skew correction as core operating variables. Those variables matter during a temperature investigation because an abnormal mechanical or process load can appear first as a bearing-temperature trend before visible damage is obvious.

Do not diagnose from temperature alone. A warmer bearing can result from lubrication problems, contamination, poor load distribution, excessive skew, bearing damage, cooling or oil-flow restriction, seal friction, or an incorrect temperature signal. The useful question is therefore not simply “Is the temperature high?” but “Which bearing is changing, under what load condition, and what changed at the same time?”

Field troubleshooting sequence

1. Confirm the measurement. Compare the control-room value with a second verified measurement method where the plant procedure allows it. Inspect the sensor installation and cable condition before assuming a bearing fault.
2. Trend against load. Note feed rate, hydraulic pressure/contact pressure, roller gap, skew indication and motor load at the time temperature starts to climb.
3. Compare all bearing positions. A single hot bearing suggests a local lubrication, alignment, clearance, seal or bearing-condition issue. A similar rise at several bearings points more toward operating load, lubricant condition, cooling or environmental effects.
4. Inspect lubrication delivery. Verify the correct lubricant is being supplied in the required quantity and condition. Look for blocked lines, low reservoir level, pump problems, leaks, contamination, foaming or evidence that the wrong lubricant was added.
5. Check contamination. Water, cement dust and wear debris can change lubricant behavior and accelerate bearing distress. Sample oil or grease according to the plant condition-monitoring program when contamination is suspected.
6. Review roller gap and skew. KHD’s Rolcox control concept continuously monitors contact pressure and roller position because skew and uneven loading directly affect roller-press behavior. If the movable roller is consistently skewed, investigate feed distribution and mechanical freedom rather than compensating only with hydraulic settings.
7. Inspect feed distribution. Uneven feed across the roller width can concentrate grinding load on one side and create asymmetric machine response. Check the feeder, chute buildup and any skew-control or dosing device.
8. Check bearing housing and support condition. Look for looseness, movement, damaged fasteners, abnormal vibration, seal rubbing, misalignment evidence or localized discoloration.
9. Correlate with vibration. Rising temperature combined with changing vibration is more serious than a stable temperature offset. Review the same bearing’s vibration trend, spectrum or condition-monitoring alarm history if available.
10. Reload gradually after correction. Do not jump directly back to maximum throughput. Confirm that temperature, vibration, gap and skew remain stable as the press returns to normal load.

Diagnostic decision matrix

What not to do

• Do not over-lubricate a grease-lubricated bearing simply because the temperature is rising; excess grease can itself increase churning and heat.
• Do not reduce grinding pressure permanently without proving that load is the root cause.
• Do not change bearing clearance or disturb the housing alignment without the OEM procedure and correct measurement tools.
• Do not ignore a temperature sensor because production appears normal; verify the sensor and preserve the alarm history.
• Do not restart repeatedly after a trip without understanding the temperature trend and the mechanical condition.

Return-to-service acceptance

After the suspected cause is corrected, restart under controlled conditions and trend the repaired bearing together with the opposite bearing, roller gap, skew indication, hydraulic/contact pressure, feed rate and vibration. Accept the machine only when the temperature trend stabilizes within the OEM/plant operating envelope, lubrication is verified, abnormal vibration is absent and the roller returns to a stable gap and skew condition. Record the before-and-after values so the next shift has an engineering baseline rather than a verbal handover.

Engineering references

• KHD Humboldt Wedag — Roller Press
• KHD Humboldt Wedag — Rolcox roller press monitoring and control
• KHD Humboldt Wedag — Roller Press Scanner and maintenance planning