Screen With Varying Cross-Sectional Apertures For Fibrous Suspension Sorting
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Solution Overview
Problem
Existing screens for treating fibrous suspensions in the paper and pulp industry face challenges in achieving optimal sorting effect and throughput while maintaining stability under hydraulic pressure, with current designs often compromising on either one or both due to rigid structure and limited screen opening sizes.
Innovation Solution
The screen openings are arranged with varying cross-sectional areas, with half being cylindrical and the other half conically expanding towards the inlet side, allowing for a larger open area without compromising stability, and featuring regular, alternating patterns of cylindrical and conical openings to enhance turbulence and sorting efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the screen openings are made larger to increase throughput, then the free screen area increases, but the sorting effect deteriorates
Solution Approach 1:
The screen openings have different cross-sectional areas at different locations: larger at the inlet side for high throughput and smaller at the outlet side for effective sorting. This local variation in opening size allows simultaneous achievement of both high productivity and good sorting effect.
Solution Approach 2:
The screen openings transition from a two-dimensional uniform pattern to a three-dimensional varying cross-section along the flow direction. This dimensional change allows the openings to provide both large inlet area for throughput and small outlet area for sorting precision.
2Measurement precision
If the screen openings are made smaller to improve sorting effect, then the sorting precision increases, but the throughput decreases
Solution Approach 1:
Different sections of the screen opening serve different functions: the larger inlet cross-section maximizes throughput while the smaller outlet cross-section ensures precise sorting. This local differentiation resolves the contradiction between quantity and quality of screening.
3Productivity
If the number of screen openings is increased to maximize free screen area, then the throughput increases, but the screen stability under hydraulic pressure decreases
Solution Approach 1:
The screen openings have varying cross-sectional parameters along their length, being larger at the inlet and smaller at the outlet. This parameter variation allows increased total open area for higher throughput while the smaller outlet dimensions and strategic positioning maintain structural stability under pressure.
4Productivity
If additional turbulence generators are added to increase throughput, then the productivity increases, but the device complexity and energy consumption increase
Solution Approach 1:
The conical screen openings themselves generate turbulence through their geometric shape, eliminating the need for separate turbulence generators. The varying cross-section creates natural flow disturbance that enhances throughput without additional components or energy consumption.
Solution Approach 2:
The turbulence-generating function is extracted from separate components and integrated into the geometry of the screen openings themselves. The conical shape inherently creates turbulence, removing the need for additional turbulence generators.
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 configuration increases throughput, improves sorting effect, and reduces energy consumption by minimizing the need for additional turbulence generators, while maintaining screen stability and allowing for cost-effective production methods like punching or laser cutting.
Implementation Method 1
This intensifies the turbulence on the inlet side of the screen, which leads to an increase in throughput.
Data Source
Figure 1~2
AI summary
The invention relates to a strainer for treating a fibrous material suspension suitable for producing a paper, cardboard, tissue, or other fibrous material web, having a plurality of strainer perforations (1, 2), the smallest cross-sectional areas of which are approximately of the same size. The sorting effect and the throughput are to be improved such that the cross-sectional areas of the strainer perforations (1, 2) on the inflow side have varying sizes.