Regular Defibration Surface for Wood Fiber Processing

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Solution Overview

Problem

Mechanical defibration of wood is energy-intensive due to excessive heat generation and lacks precise control over pressure pulses, as existing methods use irregular three-dimensional grinding surfaces with uncontrolled grit spacing and uniform grit characteristics.

Innovation Solution

A regular two-dimensional defibration surface with grinding grits positioned at predetermined distances and patterns, allowing for controlled pressure pulse amplitude and frequency, directing pulses along the fiber direction to optimize energy use and fiber deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If irregular three-dimensional grinding surfaces with random grit positioning are used, then the defibration process can be performed, but energy consumption is excessively high due to uncontrolled heat generation

Engineering Contradiction:
Improveenergy consumptionVSAvoidheat generation
Core Design Contradiction:
Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The invention changes the geometric parameters of the grinding surface from random three-dimensional irregularities to regular two-dimensional patterns with controlled grit spacing. This parameter transformation enables precise control over pressure pulse frequency and amplitude, reducing energy waste while maintaining effective defibration.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The regular periodic arrangement of grinding grits creates rhythmic pressure pulses at controlled intervals as the surface rotates. This periodic action pattern ensures consistent energy distribution across the wood surface, preventing energy concentration in specific areas and reducing overall energy consumption compared to random grit arrangements.

Inventive Principle:
Principle #19Periodic action

2Ease of operation

If irregular three-dimensional grinding surfaces are used, then fiber loosening can be achieved, but precise control over pressure pulse amplitude and frequency is lost

Engineering Contradiction:
Improvecontrol over pressure pulsesVSAvoidpressure pulse control
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The invention transforms the grinding surface from an irregular three-dimensional structure to a regular two-dimensional pattern where grit spacing, size, and arrangement are precisely controlled. This parameter standardization enables exact control over pressure pulse characteristics, allowing operators to adjust amplitude and frequency based on specific processing requirements.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The grinding surface is segmented into discrete, regularly spaced grit elements rather than being a continuous irregular surface. This segmentation allows each grit to function as an independent pressure application point, enabling precise control over the timing and magnitude of pressure pulses through controlled grit distribution patterns.

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If uniform grinding grit characteristics are used, then the surface structure is simple, but independent control of pressure pulses and fiber loosening is not possible

Engineering Contradiction:
Improveindependent control of pressure pulsesVSAvoidgrinding surface structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention applies local quality variation by creating different regions or patterns of grit arrangement on the grinding surface. Different areas can have varying grit densities, sizes, or spacing to target specific functional requirements - such as increased pressure pulse amplitude in certain zones or enhanced fiber loosening in other areas - while maintaining overall structural regularity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The regular patterned structure enables dynamic control of the defibration process through adjustable rotation speed and feed rate. The consistent geometric pattern allows the system to adapt to different operating conditions by modifying these parameters, providing versatility without requiring complex variable-geometry structures.

Inventive Principle:
Principle #15Dynamics

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

Significantly reduces energy consumption and improves fiber length and pulp quality by ensuring consistent pressure distribution and controlled fiber deformation, enhancing the efficiency of the defibration process.

Implementation Method 1

The friction between the grinding grits and the wood loosens fibers from the surface of the wood raw material

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

Pressure pulses cause deformations and generation of heat in the wood raw material and as a result of this the wood material becomes softer

Methodology Applied
Scientific EffectPressure pulses: Pressure Increase

Implementation Method 3

the frequency and amplitude of the pressure pulses formed in the defibration process can be controlled. Furthermore, the positioning of the grinding grits in the direction of the fiber makes it possible to direct the pressure pulses in a desired manner along the longitudinal direction of the fiber

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Data Source

PatentEP2013409B1Device and method for defibration of wood
Publication Date: 2017.09.20 MYLLYKOSKI
  • EP2013409B1 patent drawingFigure 1~3
  • EP2013409B1 patent drawingFigure 4a~4b
  • EP2013409B1 patent drawingFigure 5~6

AI summary

A device for mechanical defibration of wood comprises a defibration surface for processing of wood raw material and loosening of fibers, said defibration surface comprising grinding grits fastened on a metal base surface. The grits (1) fastened on the metal base surface (2) are positioned within a determined distance from each other on the base surface, so that they form a regular defibration surface.