Refiner Blade Segment Geometry for Stable Flow and Low Vibration

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Solution Overview

Problem

Existing refiners for fibrous materials experience flow variations and vibrations due to inconsistent angles of incidence between rotor and stator openings, leading to inefficiencies in the refining process.

Innovation Solution

The blade segments are designed with side edges that deviate from the longitudinal axis, creating slit-like openings with varying angles of incidence, which stabilize the flow path and reduce vibrations by aligning the point of incidence away from the axial direction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the blade segment side edges are configured parallel to the longitudinal axis, then the structure is simple and easy to manufacture, but flow variations and vibrations occur due to inconsistent angles of incidence between rotor and stator openings

Engineering Contradiction:
Improveflow stabilityVSAvoidblade segment geometry
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The blade segment side edges are configured with asymmetric angles relative to the longitudinal axis. The first side edge forms a first angle and the second side edge forms a second angle, creating slit-like openings with varying angles of incidence. This asymmetric configuration stabilizes the flow path and reduces vibrations by ensuring consistent angular relationships between rotor and stator openings throughout the refining chamber.

Inventive Principle:
Principle #4Asymmetry

2Productivity

If the slit-like openings are aligned axially, then the flow path is direct, but flow pulse variations and vibrations increase due to inconsistent angles of incidence

Engineering Contradiction:
Improverefining efficiencyVSAvoidvibrations
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The angles of the blade segment side edges are specifically designed to create slit-like openings with optimized angles of incidence. By changing the angular parameters of the openings rather than using simple axial alignment, the flow path becomes more stable and consistent, reducing flow pulse variations and vibrations while maintaining efficient material flow through the refining chamber.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3919675B1Blade segment for a refiner
Publication Date: 2026.04.15 VALMET TECH OY
  • EP3919675B1 patent drawingFigure 1
  • EP3919675B1 patent drawingFigure 2~3
  • EP3919675B1 patent drawingFigure 4a~4b

AI summary

A blade segment (4, 8) for a refiner (1) for refining fibrous material. The blade segment (4, 8) comprises a first (20) and a second (21) end edge opposite to the first end edge in a direction of a longitudinal axis(LA) of the blade segment (4, 4a, 4b, 8, 8a, 8b), a first (22) and a second (23) side edge opposite to the first side edge, the first side edge and the second side edge extending between the first end edge and the second end edge, and a refining surface (5, 9) comprising blade bars (26) and blade grooves (27) therebetween on a front surface (25) of the blade segment (4, 8). Atleast one side edge (22, 23) comprises at least two edge portions (31, 33, 35, 41, 43, 45) arranged to deviate from the direction of the longitudinal axis (LA) of the blade segment (4, 4a, 4b, 8, 8a, 8b) and being connected by an elbow (32, 34, 42, 44) between each two edge portions (31, 33, 35, 41, 43, 45).