Refining Segment Backflow Groove for Shive Reduction

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Solution Overview

Problem

Existing refining processes for lignocellulosic materials produce shives, which contaminate pulp quality and degrade refiner performance, necessitating a reduction in shive content without compromising pulp properties.

Innovation Solution

A refining segment with a backflow guide groove that collects and redirects backward-flowing fibrous material and shives back into the refining gap, enhancing the refining effect and reducing shive content.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If refiners process lignocellulose-containing fibrous material, then pulp is produced, but shives are generated that contaminate pulp and degrade refiner performance

Engineering Contradiction:
Improvepulp productionVSAvoidshive contamination
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The invention converts the harmful backward-flowing shives into a beneficial recirculating feedstock. By providing a recirculating feed groove that collects shives from the refining gap and redirects them as feed material, the system transforms contamination into a resource, enabling continuous refining without shive accumulation or quality degradation.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

Instead of discarding shives as waste or harmful byproduct, the invention recovers them through the recirculating feed groove system. The groove collects shives that would otherwise contaminate the pulp, and returns them to the refining process as feed material, achieving both contamination removal and resource recovery.

Inventive Principle:
Principle #34Discarding and recovering

2Productivity

If shives accumulate on refining surfaces, then refiner capacity decreases, but removing shives requires additional processing steps

Engineering Contradiction:
Improverefiner capacityVSAvoidprocessing steps
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The refiner system performs self-cleaning and self-recycling through the recirculating feed groove. The groove automatically collects shives from the refining gap and redirects them as feed material, eliminating the need for external cleaning mechanisms or additional processing steps to remove shives. The system serves itself by converting its own contamination into a functional feedstock.

Inventive Principle:
Principle #25Self-service

3Manufacturing precision

If refining is intensified to reduce shives, then pulp quality improves, but energy consumption increases

Engineering Contradiction:
Improvepulp qualityVSAvoidenergy consumption
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The recirculating feed groove enables continuous refining action by constantly returning shives as feed material. This continuous recirculation maintains consistent refining intensity without energy fluctuations, ensuring steady pulp quality improvement while avoiding the energy spikes that would result from intermittent intensive refining cycles.

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentEP4414500B1Refining segment
Publication Date: 2026.05.13 VALMET TECH OY
  • EP4414500B1 patent drawingFigure 1~3
  • EP4414500B1 patent drawingFigure 2
  • EP4414500B1 patent drawingFigure 4A~4B

AI summary

A refining segment (4) for a refiner (1) for refining lignocellulose-containing fibrous material. The refining segment comprises an inner end edge (20) and an outer end edge (21) opposite to the inner end edge, and a refining surface (5) comprising refining bars (25) and refining grooves (26) therebetween. The refining surface comprises at least one recess (27, 27', 27") extending from the outer end edge of the refining segment at least partly towards the inner end edge for forming at least partly at least one backflow guide groove (28) extending from the outer end edge of the refining segment at least partly towards the inner end edge. A volume of the at least one recess is arranged to decrease towards the inner end edge for providing the volume of the at least one backflow guide groove to decrease towards the inner end edge.