Rotating Drum Sorting Section for Waste Paper Dissolution
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Solution Overview
Problem
Existing methods for dissolving fibrous materials, such as waste paper, result in high fiber losses, especially with difficult-to-dissolve materials, and often damage impurities due to aggressive processing.
Innovation Solution
The implementation of a sorting section with multiple axial zones of varying perforation sizes, followed by a post-dissolving stage with a sedimentation unit and additional sorting zones for comprehensive separation and minimization of fiber losses, allows for efficient separation of fine and coarse fractions and reduces fiber loss by subjecting only difficult materials to intensive processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If a single sorting zone with uniform perforation size is used, then the device complexity is low, but fiber losses are high for difficult-to-dissolve materials
Solution Approach 1:
The sorting section is divided into multiple sorting zones (first, second, and third sorting zones) with different perforation sizes arranged axially along the drum. Each zone handles different particle sizes, with the first zone having smaller openings for fine fractions, the second zone with larger openings for difficult-to-dissolve materials, and the third zone with intermediate openings. This segmentation allows selective processing that minimizes fiber losses while managing device complexity through modular zone design.
2Productivity
If aggressive pulping with rotors is used, then difficult fibrous materials are dissolved effectively, but impurities are destroyed and fiber damage occurs
Solution Approach 1:
Different levels of mechanical action are applied in different zones: the first sorting zone uses gentle screening with smaller perforations for easy-to-dissolve materials, the second sorting zone uses larger perforations and more intensive but localized action for difficult-to-dissolve materials, and the third sorting zone provides intermediate processing. This local differentiation of processing intensity ensures effective dissolution where needed while protecting materials that require less intensive treatment, thereby reducing overall fiber damage and impurity destruction.
3Manufacturing precision
If multiple sorting zones with varying perforation sizes are implemented, then fiber losses are minimized and separation quality is improved, but the device complexity increases
Solution Approach 1:
Multiple sorting zones are arranged axially along the length of the drum, utilizing the longitudinal dimension to create a sequential processing path. The first sorting zone with smaller perforations, the second zone with larger perforations, and the third zone with intermediate perforations are positioned at different axial locations. This spatial arrangement allows progressive separation of different particle sizes while maintaining a compact cylindrical structure, improving separation quality without excessive complexity increase.
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 minimizes fiber losses and protects easy-to-open materials by optimizing the separation process, ensuring high-quality fine fractions and efficient rejection of coarse materials, thereby enhancing the overall efficiency of the dissolving process.
Implementation Method 1
the fibrous material suspension is passed from the dissolving section into a sorting section of the drum, in which a division into at least one fine and at least one coarse fraction takes place
Implementation Method 2
While the fine fraction passes through the perforation, i.e. the sorting openings of the drum, the coarse fraction is rejected with the refuse
Data Source
Figure 1
AI summary
The invention relates to a method for dissolving fibrous materials (1), in particular waste paper, wherein the fibrous materials (1) are supplied to a dissolving section (2) of a rotating drum and mixed there with water, and the fibrous material suspension is directed from the dissolving section (2) into a sorting section of the drum in which a division into at least one fine fraction (11, 12, 13) and at least one coarse fraction (8, 14, 15) is carried out. The fiber losses in difficult-to-dissolve fibrous materials (1) are reduced in that the sorting section comprises multiple sorting zones (3, 4, 5) arranged axially adjacent to one another, wherein the size of the sorting openings of adjacent sorting zones (3, 4, 5) differs, the sorting section begins with a first sorting zone (3) with smaller sorting openings, and the fine fraction (12) of the adjoining second sorting zone (4) is directed into a secondary dissolving stage (7) with larger sorting openings.