Conical Refiner Plate With Jagged Sidewalls
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Solution Overview
Problem
Conical refiners in mechanical pulping processes face inefficiencies due to high friction, leading to low energy efficiency (10-15%) and reduced operating life of refiner plates, as conventional designs focus on reducing the gap between plates to increase energy efficiency, which results in fiber cutting and pulp strength reduction.
Innovation Solution
Designing refiner plates with a curved and jagged outer section to increase retention time in the peripheral refining zone, allowing a wider operating gap while concentrating energy input, thereby enhancing energy efficiency and extending plate life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the operating gap between refiner plates is reduced to increase energy efficiency, then energy efficiency improves, but fiber cutting increases and pulp strength reduces
Solution Approach 1:
The refiner plate design implements local quality by creating different bar configurations in different radial zones. The inner zone has bars oriented to reduce friction and maintain fiber length, while the outer zone has bars oriented to increase compression and refining efficiency. This allows energy efficiency to be improved in the outer zone without compromising fiber quality in the inner zone.
Solution Approach 2:
The refiner plate is segmented into multiple radial zones with different bar orientations and configurations. Each zone is optimized for its specific function: the inner zone focuses on gentle feeding and fiber preservation, while the outer zone focuses on intensive refining and energy efficiency. This segmentation allows simultaneous optimization of conflicting requirements in different regions.
2Use of energy by moving object
If the operating gap between refiner plates is reduced to increase energy efficiency, then energy efficiency improves, but refiner plate wear rate increases and operating life reduces
Solution Approach 1:
The design applies local quality by orienting bars in the outer zone to maximize refining efficiency and energy effectiveness, while maintaining a sufficient operating gap in the inner zone to reduce friction and wear. This allows high energy efficiency where needed without subjecting the entire plate system to excessive wear conditions.
Solution Approach 2:
The refiner plate design incorporates dynamic bar orientations that adapt to the radial position and operating conditions. The bar angles are optimized for each radial zone to dynamically balance refining efficiency with wear reduction, allowing the system to maintain high energy efficiency while extending plate operating life through optimized local conditions.
3Use of energy by moving object
If friction between wood chips and refiner plates is reduced to improve energy efficiency, then energy efficiency improves, but fiber separation and development efficiency may be compromised
Solution Approach 1:
The refiner plate implements local quality by creating low-friction conditions in the inner zone for efficient fiber feeding and high-friction conditions in the outer zone for effective fiber separation and development. This allows energy efficiency to be improved through reduced friction in the feeding zone while maintaining productivity through controlled friction in the refining zone.
Solution Approach 2:
The refiner plate is segmented into functional zones with different surface characteristics and bar orientations. The inner zone is designed for low-friction feeding to improve energy efficiency, while the outer zone is designed for high-friction refining to maintain fiber separation efficiency. This segmentation resolves the contradiction by applying different friction characteristics to different functional regions.
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 design increases energy efficiency, maintains high fiber quality, and extends the operational life of refiner plates by shifting energy input to the periphery, allowing for reduced energy consumption and improved pulp production.
Implementation Method 1
The raw cellulosic material, typically wood or other lignocellulosic material (collectively referred to as wood chips), is fed through the middle of one of the refiners discs and propelled outwards by a strong centrifugal force created by the rotation of a rotor disc.
Implementation Method 2
Steam generated during refining displaces the wood chips through the conical zone.
Implementation Method 3
The refiner plates generally feature a pattern of bars and grooves, as well as dams, which together provide a repeated compression and shear actions on the wood chips. The compression and shear actions acting on the material separates the lignocellulosic fibers out of the raw material
Implementation Method 4
The refiner plates generally feature a pattern of bars and grooves, as well as dams, which together provide a repeated compression and shear actions on the wood chips.
Implementation Method 5
In the mechanical pulping process, a large amount of friction occurs, such as between the wood chips and the refiner plates. This friction reduces the energy efficiency of the process.
Data Source
AI summary
A refining plate segment for a mechanical refiner of lignocellulosic material including: a convex conical refining surface on a convex conical substrate of the plate, wherein the refining surface is adapted to face a concave conical refining surface of an opposing refiner plate, the convex conical refining surface including bars and grooves formed between adjacent bars, wherein an angle of each bar with respect to a reference line parallel to a rotational axis of the refiner increases at least 15 degrees and the angle is a holdback angle is 10 to 45 degrees at a periphery of the refining surface, and wherein the bars each include a leading sidewall having an irregular surface having protrusions extending outwardly from the sidewall toward a sidewall on an adjacent bar.