Refining Segment Backside Recirculation for Pressure Control
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Solution Overview
Problem
The control of pressure over multiple series-connected refiners in paper production is challenging, and there is a risk of fibrous material accumulating on the backside of refining segments, which can lead to instability and quality issues in the final product.
Innovation Solution
A novel refining segment design that recirculates a portion of the fibrous material through a space on the backside of the refining segment, allowing for pressure control and preventing material accumulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple refiners are connected in series to increase production volume, then productivity increases, but pressure control becomes challenging and device complexity increases
Solution Approach 1:
The refiner is divided into multiple refining segments arranged in series, allowing independent control of each segment while achieving overall high productivity. Each segment can be optimized for specific refining tasks, making the complex system more manageable.
Solution Approach 2:
A recirculation system acts as an intermediary between refining segments, allowing fibrous material to be circulated back through the system. This enables pressure balancing and improved control across multiple series-connected refiners without requiring complex external control mechanisms.
2Strength
If refining segments are designed with solid backside, then structural strength is improved, but fibrous material accumulates and gets trapped
Solution Approach 1:
The backside of the refining segment is designed with a porous structure instead of being solid. This allows fibrous material to pass through the backside, preventing accumulation and trapping while maintaining sufficient structural strength for operation.
Solution Approach 2:
The design allows fibrous material to move in an additional dimension by passing through the backside of the segment. This three-dimensional flow path prevents material accumulation that would occur with traditional solid backsides.
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 solution facilitates easier control of pressure over multiple refiners, prevents material accumulation, and improves the quality of the final product by maintaining hygiene and preventing color defects.
Implementation Method 1
recirculating a portion of the fibrous material to be refined through a space arranged on a backside of the refining segment
Data Source
AI summary
A refining segment (4, 8) for a refiner (1) for refining fibrous material has a body (20) with a front side (21) and a backside (22). The front side has a refining surface (5, 9) and the backside has a background surface (23). The refining segment has a first end edge (15) and a second end edge (16) opposite to the first end edge, and a first side edge (17) and a second side edge (18) opposite to the first side edge. The first side edge and the second side edge extend between the first end edge and the second end edge. The refining segment has backside support projections (29, 30) which project from the background surface and extend substantially along the first side edge and the second side edge without support projections extending substantially along the first end edge and the second end edge on the background surface.