Refining Apparatus with Annular Grooves for Pulp Processing

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Solution Overview

Problem

Existing beating arrangements for water-suspended cellulose fibers are inefficient due to rapid wear of grinding surfaces and suboptimal adaptation to fibrous materials, leading to excessive energy consumption and inadequate fiber treatment.

Innovation Solution

The grinding surfaces feature annular elevations and depressions arranged concentrically to the axis of rotation, with alternating elevations and depressions in the radial direction on both surfaces, and partially closed grooves with barriers to enhance fiber transfer and turbulence, maintaining treatment intensity while minimizing wear and preventing clogging.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional flat grinding surfaces are used, then the structure is simple and easy to manufacture, but the fiber treatment efficiency is low and wear occurs rapidly

Engineering Contradiction:
Improvefiber treatment efficiencyVSAvoidgrinding surface structure
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The grinding surface is segmented into multiple grinding bars arranged radially, with each bar containing grooves that divide the surface into distinct treatment zones. This segmentation increases the effective grinding area and improves fiber treatment efficiency while maintaining manageable complexity through modular design

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The grinding surface features localized variations in groove depth and bar height, creating regions with different grinding intensities. This local quality variation optimizes fiber treatment in different radial zones, allowing efficient processing without requiring complete redesign of the entire surface structure

Inventive Principle:
Principle #3Local quality

2Duration of action of moving object

If grinding bars with uniform height are used, then manufacturing is simple, but wear is excessive and treatment intensity is insufficient

Engineering Contradiction:
Improvegrinding surface lifespanVSAvoidgrinding bar fabrication
Core Design Contradiction:
Duration of action of moving objectVSEase of manufacture

Solution Approach 1:

The grinding bars are designed with varying heights that create dynamic treatment zones as fibers pass through the grinding gap. This dynamic structure optimizes contact between fibers and grinding surfaces, reducing excessive wear on any single area while extending overall component lifespan

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The groove depth and bar height parameters are strategically varied across the radial direction to optimize both wear distribution and treatment intensity. This parameter variation allows the structure to withstand prolonged operation while maintaining manufacturing feasibility through standardized production methods

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the distance between grinding bars is reduced to increase treatment intensity, then fiber processing improves, but clogging occurs more frequently

Engineering Contradiction:
Improvefiber processing efficiencyVSAvoidclogging resistance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The grinding surface is divided into multiple narrow grinding bars separated by grooves, creating numerous small treatment channels. This segmentation maintains high treatment intensity through increased surface area while the groove spacing prevents clogging by allowing fiber suspension to flow freely between bars

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The groove dimensions and bar spacing are locally optimized in different radial zones to balance treatment intensity and clogging resistance. In regions prone to clogging, wider spacing is provided while maintaining overall high efficiency through localized quality variations

Inventive Principle:
Principle #3Local quality

4Manufacturing precision

If energy consumption is increased to improve fiber treatment, then fiber properties improve, but operational costs increase

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

Solution Approach 1:

The segmented grinding surface with multiple bars and grooves increases the effective treatment area, allowing achieving the same fiber quality improvement with lower energy input per unit area. The distributed grinding action across multiple bars reduces the energy concentration required compared to conventional flat surfaces

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The varying groove depths and bar heights create optimized flow patterns that reduce energy losses. This parameter optimization ensures that energy is used efficiently for fiber treatment rather than being lost to turbulence and friction, achieving better fiber properties at lower energy consumption

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

This configuration significantly increases the efficiency of fiber treatment, reduces energy consumption, and optimizes the use of refining surfaces, leading to improved fiber properties and extended equipment lifespan.

Implementation Method 1

the grinding surfaces are formed by replaceable grinding assemblies screwed to the corresponding support surface

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

grinding cellulose fibers, i.e., virgin pulp and/or recycled paper fibers, in order to achieve the desired properties in the resulting fiber web

Methodology Applied
Scientific EffectAbrasion: Abrasion

Data Source

PatentEP3380668B1Refining apparatus
Publication Date: 2019.08.28 VOITH PATENT GMBH
  • EP3380668B1 patent drawingFigure 1~2
  • EP3380668B1 patent drawingFigure 3~6

AI summary

The invention relates to a refining assembly for refining water-suspended pulp fibers (1) between two coaxial refining surfaces (2, 3) which form a refining gap (6), rotate in relation to each other and are formed by refining bars (4) and grooves (5) extending therebetween, at least the essential directional component of the refining bars (4) extending radially in relation to the axis of rotation (7). In order make the refining process more efficient, the refining bars (4) have annular elevations (8) and depressions (9) that run concentrically to the axis of rotation (7) of the refining surfaces (2, 3), an annular elevation (8) of one refining surface (2, 3) protruding into an annular depression (9) in the opposite refining surface (3, 2).