Curved Gap Base Geometry in Star Screen Sieving
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Solution Overview
Problem
Conventional sieving devices face issues with long-fiber, thread-like, rope-shaped, or windable components in screening materials that can wrap around the gaps between sieve stars, causing energy requirements to increase or damaging the stars due to accumulation and axial tension.
Innovation Solution
The design incorporates a sieving device with a unique arrangement of sieve stars where the gap base between them is monotonically curved, with a radius of curvature that increases from the sides to the center, and a coupling mechanism that prevents windable materials from being pulled into joints, using a meandering joint shape to enhance torque transmission and reduce wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional star screens are used with straight gap bases, then the structure is simple and easy to manufacture, but windable materials wrap around the gap base causing increased energy consumption and potential damage
Solution Approach 1:
The gap base is designed with a curved geometry instead of a straight configuration. The curvature radius varies along the gap base length, creating a smooth transition that prevents windable materials from wrapping around and accumulating. This curved design guides materials away from the gap base while maintaining structural integrity.
Solution Approach 2:
Different sections of the gap base have different curvature radii. The curvature radius varies along the length of the gap base, with specific values optimized for different locations. This local variation in geometric properties allows the gap base to effectively guide materials away in critical areas while maintaining simplicity in other regions.
2Reliability
If the gap base has a monotonically increasing curvature radius, then windable materials are effectively guided away, but manufacturing precision requirements increase
Solution Approach 1:
The curvature radius of the gap base is varied as a parameter along its length. By defining specific curvature radius values at different positions (e.g., first curvature radius in one section, second curvature radius in another section), the design achieves effective material guidance through controlled geometric variation rather than complex continuous curves.
3Productivity
If star screens are arranged with interlocking fingers, then screening effectiveness is improved, but windable materials can accumulate at the gap base causing axial tension and wear
Solution Approach 1:
The curved gap base design converts the potential harmful accumulation of windable materials into a beneficial guiding mechanism. The curvature is designed to actively direct windable materials away from the gap base and toward designated discharge areas, transforming what would be a problematic accumulation into an controlled material flow pattern that reduces axial tension and wear.
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Sieving device for sieving a feed material, such as municipal waste, wood chips or soil-covered crops, the sieving device (1) comprising: 1.1 a first sieve star (7; 37) rotatably arranged about a first axis of rotation (2), which has several fingers (11) distributed around the first axis of rotation (2) and which project from a base (12) of the first sieve star (7; 37) to a free peripheral end (13) from the first axis of rotation (2), 1.2 a second sieve star (8; 38) which is adjacent to the first sieve star (7; 37) along the first axis of rotation (2) and is arranged so as not to rotate relative to the first sieve star (7; 37) and has several fingers (11) distributed around the first axis of rotation (2) and which project from a base (12) of the second sieve star (8; 38) to a free peripheral end (13) to excel, 1.3 and a third sieve star (9; 39), which is rotatably arranged about a second axis of rotation (3) extending radially next to the first axis of rotation (2) and has several fingers (11) distributed around the second axis of rotation (3), which project from a foot region (12) of the third sieve star (9; 39) to a free peripheral end (13) away from the second axis of rotation (3) and, when the third sieve star (9; 39) is rotated, project successively into a gap remaining between the foot region (12) of the first sieve star (7; 37) and the foot region (12) of the second sieve star (8; 38) to near a gap base (20), 1.4 wherein an axial center of the first sieve star (7; 37) has an axial center distance D to an axial center of the second sieve star (8; 38), 1.5 wherein the gap base (20) has an axial central section (21) and extends from this to both sides over a length L > 0.1•D everywhere with a radius of curvature K, with D > K > 0.1•D, monotonically increases to counteract an accumulation of coilable material on the sides of the gap base.