TL;DR
Worn refiner plates reduce refining intensity and increase specific energy consumption. Measure bar height with a depth gauge and replace when below the minimum height in the plate specification.
What you might see
- rising specific energy consumption for the same freeness target
- freeness harder to control, drifting high
- increased plate gap required to maintain the same power draw
- visible bar edge rounding on plate surface
Likely causes
Normal bar edge wear from fiber and filler abrasion over service hours
Accelerated wear from sand, grit, or reject contamination in the pulp
Incorrect plate selection for the furnish type causing faster bar erosion
Plate-to-plate contact events from gap vibration accelerating surface damage
Required tools
- Depth gauge (for bar height measurement)
- Torque wrench
- LOTO kit
- Cleaning brush
Safety first
- Refiner plates have sharp bar edges. Use cut-resistant gloves during plate handling and installation.
- Lock out and fully depressurize the refiner before opening the plate housing.
Procedure
- 1
Log the specific energy trend (kWh/t) versus freeness over the last 30 days. A rising specific energy for the same freeness target indicates plate wear.[1]
- 2
Shut down the refiner per LOTO procedure and allow the plate housing to cool before opening.
- 3
Open the plate housing and clean the plate surface of fiber deposits before measuring.
- 4
Measure bar height at five locations across the plate radius using a depth gauge. Record all readings.[1]
- 5
Compare readings to the minimum bar height in the plate specification sheet. Replace if any measurement is at or below the minimum.
- 6
Inspect the plate segment joints for cracking or loosening fasteners. Loose segments are a safety hazard and require immediate plate removal.
- 7
When installing new plates, verify torque on all fasteners to the specification before restarting.
Sources
Valmet Valmet OptiFiner Pro Refiner / Pulper general technical documentation, Valmet
Disk refiner plate wear measurement and replacement, general pulp refining practice (general)
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