Rotor Functional Surfaces for Stock Preparation

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Solution Overview

Problem

Existing fiber processing systems face inefficiencies in producing uniform fiber suspensions due to the presence of specks and paper particles that are difficult to break down, leading to fiber loss and entanglement, and require high energy consumption and ineffective material friction for further disintegration.

Innovation Solution

The implementation of rotors with functional surfaces that generate vortices and apply shear forces to specks and paper particles, breaking them down into individual fibers, while minimizing energy input and wear, by positioning these surfaces away from the main flow direction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If material friction is used for further disintegration of paper particles, then the process continues to break down particles, but the process becomes very ineffective, time-consuming, and associated with high energy consumption

Engineering Contradiction:
Improvedisintegration efficiencyVSAvoidenergy consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The rotor surface is segmented into multiple functional zones with different surface characteristics (smooth vs. rough areas) that perform different functions: the smooth areas handle high-speed particle breakdown while the rough areas provide friction-based refinement, allowing simultaneous operation of multiple disintegration mechanisms

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The surface roughness parameter of the rotor is changed by providing both smooth and rough areas on the rotor surface. The rough areas have increased surface friction coefficients that enhance mechanical friction disintegration of paper particles, directly addressing the inefficiency of conventional smooth-surface rotors

Inventive Principle:
Principle #35Parameter changes

2Productivity

If conventional smooth rotor surfaces are used, then energy consumption is lower, but the disintegration of specks and paper particles is ineffective and time-consuming

Engineering Contradiction:
Improveparticle breakdown efficiencyVSAvoidenergy consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

Different local areas of the rotor surface are given different qualities: smooth areas for low-friction high-speed operation and rough areas for high-friction particle breakdown. This local differentiation allows the rotor to provide enhanced particle disintegration only where needed, rather than increasing friction across the entire surface

Inventive Principle:
Principle #3Local quality

3Manufacturing precision

If the rotor processes paper particles extensively, then particle size is reduced, but remaining particles and specks still persist in the accept pulp requiring secondary processing

Engineering Contradiction:
Improvefiber suspension uniformityVSAvoidprocessing system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The rotor is designed to perform multiple functions within a single device: initial particle breakdown, speck disintegration, fiber separation, and suspension uniformity enhancement. This multi-functionality eliminates or reduces the need for separate secondary processing equipment, simplifying the overall system while achieving high manufacturing precision

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

This approach enhances the quality of fiber suspensions by increasing the proportion of free, isolated fibers, reduces fiber loss, and improves processing efficiency with lower energy consumption and reduced wear.

Implementation Method 1

Locally generated vortices cause specks and/or paper particles to slide along the functional surfaces

Methodology Applied
Scientific EffectVortex: Vortex Ring

Implementation Method 2

The specks or paper particles are subjected to friction and/or shear forces and are broken down into individual fibers

Methodology Applied
Scientific EffectShear force: Shear Stress

Implementation Method 3

The specks or paper particles are subjected to friction and/or shear forces and are broken down into individual fibers

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4367320B1Rotor for use in stock preparation
Publication Date: 2025.08.13 VOITH PATENT GMBH
  • EP4367320B1 patent drawingFigure 1~2
  • EP4367320B1 patent drawingFigure 3
  • EP4367320B1 patent drawingFigure 4a~4b

AI summary

The invention relates to rotating rotors, impellers and propellers, hereinbelow referred to as rotors (21), for use in a stock preparation plant (1). The rotors are partly or wholly provided with functional surfaces (41). The functional surfaces are elevations and depressions having dimensions of 0.15 mm to 5 mm from a peak to the trough. The functional surfaces improve the quality of the fiber suspension. • - Fiberization is improved with regard to paper particles and specks. • - The paper suspension is homogenized. • - Any slight fiber entanglements are treated. • - Linear particles are comminuted until undetectable. - The fibers are slightly fibrillated, thus contributing to an increase in strength of the paper. • - The paper fibers are cleaned and the cleaned fibers contribute to an increase in paper strengths. • - Hornified fibers are partially treated to reactivate the hornified OH groups. The activation of the OH groups contributes to an increase in strength of the paper. • - The increase in strength due to the treated paper fibers makes it possible to economize on chemicals.