TL;DR

Excessive fall-through dust and hot particles under the grate mean worn or cracked grate plates. Schedule a grate plate inspection at the next kiln stop and replace damaged plates.

What you might see

cooler fall-through dust above normal
hot clinker particles in the under-grate dust
pressure loss in one grate zone
cooling efficiency declining per unit clinker

Likely causes

Tap to mark as ruled out

Normal thermal and abrasive wear of the cast grate plate over its service life
Grate plate cracking from thermal shock during kiln feed upsets
Clinker surges overloading the grate and causing plate-to-plate impact damage
Plate fasteners loosening and allowing plate displacement

Required tools

Confined-space entry equipment (gas monitor, harness, rescue line)
Wrench set for plate fasteners
Replacement grate plates and fasteners
LOTO kit

Safety first

Confined-space entry into the cooler requires a formal permit, atmospheric testing for oxygen and CO, and a standby rescue team.
Residual radiant heat inside the cooler after a kiln stop. Verify the temperature is safe before entry.
Cement dust explosion risk. No open ignition sources inside the cooler.

Procedure

8 steps · ~90 min

1
Coordinate grate plate inspection with the next planned kiln stop. The cooler must be empty and locked out.
Warning: The cooler interior will retain significant residual heat after a kiln stop. Allow adequate cooling time before entry and verify the temperature is below 50 degC before any confined-space entry.
2
Lock out all cooler drives, grate drives, cooling fans, and the kiln discharge chute.
3
Enter the cooler using the confined-space entry procedure. Confirm atmospheric oxygen level and CO below the alarm threshold.[1]
4
Inspect each grate plate row systematically. Mark cracked, worn through, or broken plates for replacement.[1]
5
Replace damaged plates with spares matching the same material grade and slot geometry.
6
Check the plate fasteners (bolts, pins) for looseness or damage. Replace any worn fasteners.
7
Before closing the cooler, clean out accumulated fall-through dust from the under-grate hoppers.
8
After restart, monitor under-grate fall-through dust rate for the first 48 hours to confirm the repair.

Sources

FLSmidth FLSmidth Cross-Bar Clinker Cooler general technical documentation, FLSmidth
FLSmidth Cross-Bar clinker cooler maintenance documentation, grate plate inspection and replacement procedures (general)

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