Why Do Refiner Plates Fail Too Early? 7 Operating Details Paper Mills Should Check

Premature refiner plate damage is not always caused by plate quality.

Installation condition, segment orientation, startup procedures, refining clearance and foreign material entering the refining zone can all influence plate condition and refining results.

Understanding these factors can help paper mills identify operating problems before they develop into serious plate damage.

Refiner Plate Size Must Match the Equipment

Refiner plate dimensions vary considerably between machine types.

Typical metric diameters include:

Ø250 / Ø300 / Ø350 / Ø400 / Ø450 / Ø500 / Ø550 / Ø600 / Ø660 / Ø700 / Ø750 / Ø800 / Ø900 / Ø1000 / Ø1200 mm

Common inch sizes include:

12" / 14" / 16" / 20" / 24" / 26" / 28" / 30" / 34" / 36" / 42" / 48"

Dimensions alone are not enough. Segment configuration must also correspond to the specific refiner.

1. Clean Mounting Surface Is Essential

Before new segments are installed, the rotor and stator mounting surfaces should be inspected.

Bolt holes and segment seating areas must also be free from pulp buildup, corrosion, metal burrs and foreign particles.

After assembly, check:

Segment Seating + Flatness + Concentricity + Fastening

Installing new segments on an unsuitable mounting surface can compromise the entire plate assembly.

2.Rotor and Stator Patterns Must Follow the Designed Direction

Where a refiner plate uses separate Rotor and Stator Patterns, their positions should never be reversed.

Plate designs incorporating specific bar angles and pumping characteristics are especially sensitive to orientation.

Incorrect positioning can contribute to:

Unstable Stock Flow → Abnormal Power Demand → Poorer Refining → Higher Vibration

Always verify the manufacturer's designated Pumping Direction before startup.

3.Dry Running Is a Major Risk

High-speed plate contact without pulp and liquid between the refining surfaces generates frictional heat very quickly.

The damage sequence may develop as:

Bar Burning → Deformation → Chipping → Major Plate Damage

For this reason:

Never run the refiner dry.

Required stock and liquid conditions should be established before normal refining operation.

4.Avoid Aggressive Plate Gap Adjustment

During startup, the refiner should operate with an appropriate initial Plate Gap / Refining Gap.

After flow, consistency and machine conditions stabilize, loading can be increased gradually.

Rapidly closing the plate gap to raise °SR can negatively affect the refining process and plate condition.

Stable operation should come first.

5.Metal Contaminants Can Destroy Refining Bars

Metal fragments entering a high-speed refining zone can severely damage refiner plates.

Common risks include bolts, pieces of metal and welding slag.

An upstream Magnetic Separator / Magnet, together with suitable heavy-contaminant removal equipment, helps reduce this risk.

Foreign material control is therefore an important element of refiner plate protection.

6.Abnormal Wear Is a Diagnostic Signal

Uniform wear is generally expected during normal operation.

When wear becomes uneven, the pattern deserves investigation.

One-sided wear: inspect concentricity, bearings and installation.

Localized damage: investigate foreign objects and segment installation.

Rounded bar tops: refining efficiency may be decreasing.

Cracks or chipped bars: evaluate replacement immediately.

Unequal rotor/stator wear: review stock flow, plate pattern and operating gap.

Plate replacement should therefore be determined by actual condition and performance rather than service time alone.

7.Reaching the Same °SR Does Not Mean Achieving the Same Refining Result

The  Schopper-Riegler Degree (°SR) remains an important pulp parameter, but it should not be used alone.

Consider two plate patterns that both change pulp from:

20°SR → 35°SR

One may create greater fiber cutting, while another may promote fibrillation.

The final °SR is identical, yet paper strength and specific energy demand can differ considerably.

A broader evaluation should include:

Freeness + Fiber Length + Fines Content + Tensile Index + Tear Index + Burst Index + Specific Energy Consumption (kWh/t)

For practical mill evaluation, consider:

Plate Condition + Refining Quality + Energy Consumption

and:

Plate Wear → Fiber Development → Paper Strength → Energy Demand

This approach provides a more complete view of refiner plate performance.

 

For Single Disc Refiner Plates, Double Disc Refiner Plates, Conical Refiner Fillings, High Consistency Refiner Plates, Low Consistency Refiner Plates, Disperser Plates and Deflaker Plates, please contact:

Huatao Group
Website: www.papermakingtech.com
Email: market@huataogroup.com
WhatsApp / WeChat: +86 180 3376 3037   

 

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