Complementary Refiner Plate Grooves for Stable Steam Evacuation

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Solution Overview

Problem

Conventional refiner plates in mechanical pulping systems experience inefficient steam flow and turbulence, leading to refiner instability and limited energy application due to abrupt groove depth changes and dams, which restrict steam evacuation and fiber treatment efficiency.

Innovation Solution

Implementing refiner plates with complementary groove profiles featuring smooth, wavy, and complementary depth transitions between opposing discs, facilitating laminar steam flow and controlled fiber retention through minimal groove depth variations and additional flow restrictors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional refiner plates with dams and abrupt groove depth changes are used, then fiber retention is improved, but steam flow efficiency deteriorates and turbulence increases

Engineering Contradiction:
Improvefiber retentionVSAvoidsteam flow efficiency
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The invention replaces abrupt groove depth changes with smooth, curved groove depth transitions. The groove depth varies gradually along the radial direction following a curved profile rather than sudden steps, which eliminates turbulence and improves steam flow efficiency while maintaining fiber retention capability.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The invention changes the groove depth parameter continuously along the radial direction instead of maintaining constant depth or abrupt changes. The groove depth transitions from deeper near the inner radius to shallower near the outer radius through a smooth curved profile, optimizing both steam flow and fiber retention.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If dams are added to grooves to restrict material flow, then fiber treatment efficiency is improved, but steam evacuation is restricted and mechanical stability deteriorates

Engineering Contradiction:
Improvefiber treatment efficiencyVSAvoidmechanical stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The invention replaces dams with smooth curved groove depth transitions that gradually change the groove depth along the radial direction. This eliminates the abrupt barriers created by dams, allowing steam to evacuate freely while still providing sufficient residence time for fiber treatment through the gradual depth variation.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The invention removes dams from the groove structure entirely and replaces their flow restriction function with smooth curved groove depth transitions. This extraction of the harmful dam element eliminates steam evacuation restrictions and mechanical instability while maintaining fiber treatment efficiency.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If groove depth varies abruptly in conventional plates, then fiber retention is enhanced, but steam flow becomes turbulent and energy application is limited

Engineering Contradiction:
Improvefiber retentionVSAvoidenergy application
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The invention uses smooth curved groove depth transitions instead of abrupt variations. The curved profile allows steam to flow laminarly through the grooves, eliminating turbulence and enabling more effective energy application to the fiber material while maintaining retention through the gradual depth change.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The invention implements continuous parameter change in groove depth along the radial direction through curved transitions. This gradual parameter variation optimizes both fiber retention and steam flow characteristics, enabling improved energy application without sacrificing retention performance.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enhances steam evacuation efficiency and mechanical stability by promoting laminar steam flow while ensuring thorough fiber treatment, reducing energy limitations and mechanical vibrations.

Implementation Method 1

facilitating laminar steam flow

Methodology Applied
Scientific EffectLaminar flow: Laminar Flow

Implementation Method 2

Due to the centrifugal forces caused by the relative rotation of the discs

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP2669427B1Set of refiner plates with complementary groove profiles
Publication Date: 2026.01.21 ANDRITZ INC
  • EP2669427B1 patent drawingFigure 1
  • EP2669427B1 patent drawingFigure 2
  • EP2669427B1 patent drawingFigure 3

AI summary

A set (300, 400) of plate segments, wherein the segments are preferably configured for a conical refiner, and wherein the set (300, 400) of plate segments comprises: a first plate segment (302, 402) including a refining face including a refining zone comprising rows of bars (350, 352) and grooves between the rows and the grooves include a first deep section at a first radius from a rotational axis of the first refiner plate segment and a first shallow section at a second radius, and a second plate segment (304, 404) including a refining face configured to oppose the refining face of the first plate segment (302, 402) when the set (300, 400) is mounted in a refiner, wherein the grooves have a second deep groove section at the second radius and a shallow section at the first radius.