Multi-Step Classification of Particulate Water Absorbent Resin
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Solution Overview
Problem
Conventional classification methods for particulate water absorbent resin, such as sieving and wind force classification, face challenges in efficiently producing desired particle diameters at low cost and high productivity, especially with larger production equipment, leading to issues like screen breakage, metal contamination, and incomplete fine powder removal.
Innovation Solution
A multi-step classification method using a combination of sieving and aerial current classification, with specific mesh sizes and differential pressures, to efficiently remove fine powder from particulate water absorbent resin, allowing for the use of smaller equipment in subsequent steps and maintaining high productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If classification by wind force is used for fine particles (≤300 μm), then classification efficiency is improved, but device size and cost increase significantly
Solution Approach 1:
The classification process is divided into multiple sequential steps: first classification (removing particles <150 μm), second classification (removing particles <106 μm), and third classification (removing particles <75 μm). Each step uses appropriately sized equipment for its specific task, avoiding the need for one large complex device to handle all classification requirements
Solution Approach 2:
The patent transitions from single-step classification to multi-step classification, adding the dimension of process stages. This allows using smaller, simpler devices in each stage rather than one large complex device, while achieving cumulative classification efficiency
2Manufacturing precision
If screen mesh size is reduced to remove fine powder, then classification precision is improved, but screen strength decreases leading to breakage and contamination
Solution Approach 1:
The screening process is segmented into multiple passes with different mesh sizes. The first pass uses a 150 μm mesh to remove most fine powder, the second pass uses a 106 μm mesh for finer particles, and the third pass uses a 75 μm mesh for ultra-fine particles. This segmentation allows each screen to operate at optimal strength-to-precision ratio
Solution Approach 2:
The patent applies partial classification at each stage rather than attempting complete fine powder removal in one step. The 150 μm mesh removes the majority of fine powder (excessive action for coarse fine particles), reducing the burden on subsequent finer meshes which then handle remaining particles with appropriate screen strength
3Device complexity
If single-step classification is used, then process simplicity is maintained, but fine powder removal is incomplete
Solution Approach 1:
The classification process is divided into three distinct classification steps, each targeting a specific particle size range. This segmentation enables complete fine powder removal by addressing different particle populations in sequence rather than attempting to remove all fine particles in one step
Solution Approach 2:
The patent introduces intermediate classification stages with mesh sizes of 150 μm and 106 μm between the initial and final classification steps. These intermediate stages act as mediators that progressively reduce particle size, making the final 75 μm classification more effective and complete
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 method enables the efficient production of particulate water absorbent resin with desired particle diameters at lower costs and higher productivity, even with larger production equipment, while minimizing the inclusion of fine powder and maintaining product performance.
Implementation Method 1
classification using an aerial current and buoyancy (classification by wind force)
Implementation Method 2
classification using an aerial current and buoyancy (classification by wind force)
Implementation Method 3
classification using a screen and gravity (classification by sieving)
Implementation Method 4
classification using a screen and gravity (classification by sieving)
Data Source
AI summary
A particulate water absorbent resin is obtained by polymerizing an unsaturated monomer so as to form a cross-linked polymer hydrogel and drying and pulverizing the cross-linked polymer hydrogel, and plural classification steps different from each other are carried out so as to remove fine powder. In this manner, the present invention provides the method for classification of particulate water absorbent resin which method allows particulate water absorbent resin having a desired particle diameter range to be efficiently obtained at low cost while securing the high productivity even in case where a larger production equipment is used.