Dammed Refiner Plate Segments for Lignocellulosic Material
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Mechanical refiners for lignocellulosic material face inefficiencies in hydraulic behavior, leading to increased power consumption, reduced pressure head, and unstable refining gaps due to inward flow within the shroud, which affects rotor balancing and refining performance.
Innovation Solution
The implementation of fully or partially dammed refiner plates with full height dams in grooves, controlling groove lengths, and optimizing the stator design to minimize inward flow and enhance hydraulic efficiency, including the use of logarithmic spiral bar designs to improve rotor-stator interaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional refiner plates with continuous grooves are used, then material flow is maintained, but hydraulic efficiency decreases and power consumption increases due to inward flow within the shroud
Solution Approach 1:
The continuous grooves in the refiner plate are segmented into discrete groove segments by dams, creating isolated chambers. This segmentation prevents the inward flow of material within the shroud region, eliminating the harmful hydraulic behavior that causes increased power consumption and reduced hydraulic efficiency while maintaining effective material flow through the refining gap.
2Ease of manufacture
If conventional refiner plates without dams are used, then manufacturing is simpler, but refining performance decreases due to unstable refining gaps and poor rotor balancing
Solution Approach 1:
Dams are added to segment the grooves into discrete sections, which stabilizes the refining gap by preventing material from flowing inward and causing fluctuations. This segmentation also improves rotor balancing by creating more uniform material distribution. The dams are integrated into the plate manufacturing process, adding minimal complexity while significantly improving refining performance and operational reliability.
3Productivity
If groove segments are made longer, then material flow is more continuous, but hydraulic efficiency decreases due to increased inward flow
Solution Approach 1:
The optimal groove segment length is determined by balancing two competing requirements: sufficient length to maintain continuous material flow and sufficient shortness to prevent inward flow that reduces hydraulic efficiency. Through parameter optimization, the groove segments are designed with specific length limits that achieve the best compromise between flow continuity and hydraulic efficiency, preventing energy loss while maintaining productive material movement through the refiner.
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 reduces energy consumption, enhances hydraulic efficiency, and stabilizes the refining gap, resulting in improved refining performance and balanced rotor operation in both low and medium consistency refiners.
Implementation Method 1
As one or both of the refiner plates rotate, centrifugal forces move the lignocellulosic material outwards through the gap and towards the periphery of the refiner plate.
Implementation Method 2
The dammed grooves on the surface of the refiner plate form segments of grooves, and each groove segment has a length of no more than about 30 mm
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Refiner plate segments (100) and refiner plates having fully dammed or partially dammed grooves (150, 180) on a major surface that may control flow behavior of lignocellulosic materials passing between refining plates in a refiner. The dammed grooves (150, 180) form groove segments, and each groove segment has a length of no more than about 30 mm or a subrange thereof.