Refiner Plate Jagged Sidewalls Energy Efficiency
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Solution Overview
Problem
Mechanical pulping processes face inefficiencies in energy transfer and fiber cutting, leading to reduced pulp strength and shorter refiner plate lifetimes due to narrow operating gaps between refiner plates, which compromise energy efficiency and operational longevity.
Innovation Solution
Development of refiner plates with a coarse bar and groove pattern, aggressive holdback angles, and serrated leading sidewalls to increase retention time and energy concentration within the refining zone, allowing for higher energy efficiency and longer plate life without reducing the gap between plates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the operating gap between refiner plates is reduced to improve energy efficiency, then energy transfer efficiency improves, but refiner plate lifetime is reduced due to excessive wear
Solution Approach 1:
The refiner plate features localized jagged leading sidewalls on specific bars rather than uniform modification across all bars. This local quality approach allows energy concentration at strategic locations where fibers enter the refining zone, improving energy transfer efficiency without requiring reduced operating gaps that would cause excessive wear across the entire plate surface.
Solution Approach 2:
The refiner plate is divided into multiple bars with differentiated functions - some bars have jagged leading sidewalls for aggressive fiber engagement and energy transfer, while other bars have smooth surfaces for reduced wear. This segmentation allows the plate to achieve high energy efficiency in specific zones without compromising overall plate lifetime.
2Use of energy by moving object
If the operating gap between refiner plates is reduced to increase compression ratio, then energy efficiency improves, but fiber cutting increases reducing pulp strength
Solution Approach 1:
Jagged leading sidewalls are applied only to specific bars in the refining zone where controlled fiber engagement is needed, rather than uniformly across all bars. This localized approach enables efficient energy transfer and fiber separation while minimizing excessive compression that would cause fiber cutting and strength loss.
Solution Approach 2:
The invention changes the geometric parameter of bar leading sidewalls from smooth to jagged, creating localized high-compression zones that efficiently separate fibers without requiring a reduced operating gap. This parameter change enables high energy efficiency while maintaining larger gaps that prevent excessive fiber cutting.
3Ease of manufacture
If conventional refiner plate designs are used with smooth bar surfaces, then manufacturing is simpler, but energy transfer efficiency is reduced due to friction losses
Solution Approach 1:
Rather than modifying all bar surfaces (which would complicate manufacturing), the invention applies jagged leading sidewalls only to specific portions of specific bars. This localized modification maintains relative manufacturing simplicity while significantly improving energy transfer efficiency by reducing friction losses at the critical fiber engagement points.
Solution Approach 2:
The bar surface is segmented into jagged leading sidewalls for high-energy fiber engagement and smooth other surfaces for reduced wear and simplified manufacturing. This segmentation achieves improved energy efficiency without requiring complete surface modification of all bars.
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
The solution achieves high energy efficiency, preserves fiber length, and extends the operational life of refiner plates by maintaining a larger gap between plates, while minimizing fiber cutting and maintaining pulp quality.
Implementation Method 1
raw fibrous material, typically wood or other lignocellulosic material, is fed through the middle of one of a refiners discs and propelled outwards by a strong centrifugal force created by the rotation of one or both discs
Implementation Method 2
a large portion of which is in an outer zone with bars having a jagged leading sidewall surface that increases the retention time of fibrous material in the outer zone
Data Source
Figure 1~2
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Figure 5~6
AI summary
A refiner plate for a mechanical refiner of lignocellulosic material including: a refining surface on a substrate, wherein the refining surface is adapted to face a refining surface of an opposing refiner plate; wherein the refining surface includes bars and grooves between the bars and the bars have at least a radially outer section in which the bars include a leading sidewall having an irregular surface in the outer section.