Refiner Plate Grooves Imparting Rotational Flow
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Solution Overview
Problem
Existing refiner discs suffer from feed material remaining too long in grooves, leading to incomplete refinement and the formation of eddy currents that trap material, reducing the effectiveness of the refining process.
Innovation Solution
The grooves are designed to impart a rotational flow to the feed material, using features such as half-helical shapes and oblique ridges to quickly move material out of the grooves and reduce turbulence, thereby minimizing eddy currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If dams are placed in the grooves to force feed material out, then material retention in grooves is reduced, but excessive turbulence and eddy currents are created that trap material
Solution Approach 1:
The groove sidewalls are formed with curved surfaces that guide material flow smoothly outward toward the bar ridges. The curved geometry eliminates sharp corners and abrupt transitions that generate eddy currents, while still effectively directing material out of the grooves and onto the bars for refining.
Solution Approach 2:
Instead of using protruding dams that block flow and create turbulence, the invention uses recessed curved surfaces that guide flow smoothly. The approach inverts the conventional dam structure by using contoured walls that facilitate rather than obstruct material movement, achieving the same goal of expelling material without generating harmful eddy currents.
2Ease of operation
If serrated or jagged sidewalls are used to move material from grooves, then material is forced out of grooves, but eddy currents form in the corners that capture and hold material
Solution Approach 1:
The groove sidewalls are formed with curved surfaces that guide material flow smoothly outward toward the bar ridges. The curved geometry eliminates sharp corners and abrupt transitions that generate eddy currents, while still effectively directing material out of the grooves and onto the bars for refining.
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 rotational flow design effectively prevents material from lingering in grooves, enhancing the refinement process by ensuring all material is subjected to compressive and shear forces, resulting in more efficient fiber separation and reducing material buildup.
Implementation Method 1
The grooves are configured to impart a rotational flow, e.g., a vortex, to the feed material flowing longitudinally through the groove. The rotational flow causes the feed material at the lowermost regions of the groove, to move toward the upper regions of the groove
Implementation Method 2
The crossing of bars create strong pulsating compressive and shear forces applied to the feed material between the bars
Implementation Method 3
The crossing of bars create strong pulsating compressive and shear forces applied to the feed material between the bars
Implementation Method 4
The compressions and shearing separate the feed material into fibers, such as separating wood chips into lignocellulosic fibers
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A refiner disc (14, 16) including: a refining zone on a front face of the disc (14, 16); refining bars (54, ...) in the refining zone; and grooves (52, ...) between the bars (54, ...), wherein each of the grooves (52, ...) include a rotation inducement element arranged on at least one sidewall of the groove (52, ...) and the rotation inducement element is configured to impart at helical flow of feed material flowing through the groove (52, ...).