Variable-Coated Refiner Filling Piece for Wear and Hydraulic Capacity

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Solution Overview

Problem

Rotary-type pulp refiners experience rapid wear of refiner bars due to abrasives in the pulp suspension, leading to frequent replacements and reduced hydraulic capacity, with existing wear-resistant coatings being expensive and prone to failure under severe conditions.

Innovation Solution

Refiner bars are coated with a variable coating that varies in thickness along the bar's length or height, focusing on areas needing maximum wear resistance and minimizing coating where it is less effective, thereby maintaining hydraulic capacity and extending service life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a uniform wear-resistant coating is applied to the leading surface of the bars, then wear resistance is improved, but the groove volume is reduced and hydraulic capacity is decreased

Engineering Contradiction:

Improvewear resistanceVSAvoidhydraulic capacity

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent applies a variable coating where the coating thickness varies along the bar length, with thicker coating at the leading surface where wear occurs and thinner or no coating at the trailing surface. This local differentiation provides wear resistance where needed while preserving groove volume and hydraulic capacity in the grooves.

Inventive Principle:

Principle #3Local quality

2Reliability

If hard coatings are applied to achieve desired hardness, then wear resistance is improved, but the bars become stiff and brittle and may fail under severe operating conditions

Engineering Contradiction:

Improvewear resistanceVSAvoidbar toughness

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent changes the coating parameters by using a variable thickness coating rather than uniform thickness. The coating transitions from thick at the leading surface to thin or absent at the trailing surface, providing wear resistance while maintaining bar flexibility and toughness under severe operating conditions.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If exotic alloys are used for coatings to achieve desired hardness, then wear resistance is improved, but manufacturing cost increases

Engineering Contradiction:

Improvewear resistanceVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies coating only where needed (thicker at the leading surface) rather than uniformly across the entire bar, reducing the total amount of expensive coating material required while maintaining adequate wear resistance in the critical wear areas.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS12454793B2Refiner filling piece having variably coated bars

Publication Date: 2025.10.28 AIKAWA FIBER TECH INC

AI summary

Disclosed is a refiner filling piece for a refiner having a rotor that rotates about an axis of rotation and cooperates with a stator to mechanically treat a pulp containing cellulosic fibers. The refiner filling piece is mountable to the rotor or the stator. The refiner filling piece comprises a base and a plurality of spaced-apart refiner bars, each refiner bar being defined by a bar length and a bar height. At least some of the refiner bars have a surface coated with a variable coating. The surface having the variable coating may be the leading surface of the bar.