Curved Side Edge Blade Segment for Disc Refiner Flow
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Solution Overview
Problem
Conventional disc refiner blade segments exhibit discontinuities at interfaces due to straight side edges, leading to disturbances in refining and pulp flow, and require precise tolerances to prevent pulp escape, while also needing reinforcements for structural strength.
Innovation Solution
The blade segment features curved side edges with a single radius of curvature, where one edge is concave and the other is convex, and the refining surface includes curved blade bars and grooves that adapt in width and depth to enhance pulp flow and structural integrity, allowing for larger manufacturing tolerances without pulp escape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If straight side edges are used for blade segments, then manufacturing is simpler, but discontinuities occur at interfaces causing disturbances in refining and pulp flow
Solution Approach 1:
The blade segment side edges are designed with curvature instead of straight lines. The first side edge has a first curvature and the second side edge has a second curvature, which eliminates discontinuities at the interfaces between adjacent blade segments. This curved design ensures continuous material flow through the refining elements without disturbances that would occur with straight-edged segments.
2Device complexity
If straight side edges are used for blade segments, then structural design is simpler, but precise tolerances are required to prevent pulp escape
Solution Approach 1:
The curved side edges with specific radii of curvature create a geometry that naturally accommodates manufacturing variations. The curvature allows for larger tolerances at the interfaces between blade segments while maintaining the integrity of the refining gap, preventing pulp escape without requiring extremely precise manufacturing tolerances.
Solution Approach 2:
The invention specifies particular ranges for the radii of curvature of the side edges (first radius between 5-50mm, second radius between 10-100mm) to optimize the balance between preventing pulp escape and allowing for practical manufacturing tolerances. These parameter specifications provide design flexibility while ensuring functional performance.
3Strength
If reinforcements are added to blade segments, then structural strength is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The curved side edge design with optimized radii of curvature inherently distributes mechanical stresses more effectively across the blade segment structure. This geometric optimization provides structural strength without requiring additional reinforcement elements, maintaining simplicity while ensuring durability under refining operations.
Data Source
AI summary
A blade segment of a disc refiner for refining fibrous material has an inner circumference and an outer circumference as well as a first side edge and a second side edge which connect the inner circumference and the outer circumference. The side edges are curved, with one convex and the other concave. The segment has a refining surface with blade bars and grooves which define a pumping direction. The side edges of the blade segment curve in the vicinity of the inner circumference in the pumping direction, and in the vicinity of the outer circumference in a non-pumping direction.