Dual-Layer Sieve for Waste Separation
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Solution Overview
Problem
Current waste separation technologies face challenges in reducing impurity content, particularly plastics, in compostable materials while maintaining throughput and service life, due to the need for finer screens which increase manufacturing time and costs, and reduce wear resistance.
Innovation Solution
A sieve design utilizing a dual-layer construction with a high-strength wear-resistant steel inner jacket and a medium-strength outer jacket, where holes are drilled separately in thinner material to reduce clogging and manufacturing time, allowing for smaller diameters and improved separating efficiency without compromising stability or throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If finer screens with smaller hole diameters are used to reduce impurity content, then separation precision is improved, but manufacturing time increases and wear resistance decreases
Solution Approach 1:
The screen is divided into multiple layers (first screen layer and second screen layer), each with different hole diameters. The first layer has larger holes for initial separation, while the second layer has smaller holes for finer separation. This segmentation allows the system to achieve high separation precision without requiring all holes to be small, thereby reducing overall manufacturing time while maintaining impurity reduction effectiveness.
2Manufacturing precision
If finer screens with smaller hole diameters are used to reduce impurity content, then separation precision is improved, but service life decreases due to reduced wear resistance
Solution Approach 1:
Different regions of the screen structure have different hole diameters optimized for their specific functions. The first screen layer has larger holes that experience higher wear from material contact, while the second screen layer has smaller holes protected by the first layer. This local quality differentiation allows smaller holes to achieve fine separation without being directly exposed to wear, thus maintaining both separation precision and service life.
3Productivity
If the number of holes is increased to maintain throughput with finer screens, then productivity is maintained, but manufacturing complexity and costs increase
Solution Approach 1:
The screen surface is segmented into multiple layers with different hole densities and diameters. The first layer has fewer, larger holes that handle the bulk of material flow, while the second layer has more, smaller holes that provide fine separation. This segmentation allows the system to maintain high throughput through the first layer while achieving fine separation in the second layer, avoiding the need to drill a very large number of small holes in a single layer.
4Strength
If thicker material is used to maintain screen stability, then structural strength is improved, but hole diameter must be increased which reduces separation precision
Solution Approach 1:
The screen is segmented into multiple layers where the first layer provides structural strength with larger holes, and the second layer provides fine separation with smaller holes. This segmentation allows the use of smaller hole diameters in the second layer without compromising overall screen stability, as the first layer bears the primary mechanical load while the second layer focuses on separation precision.
5Reliability
If high-strength wear-resistant steel is used to improve wear resistance, then service life is improved, but ability to form curved shape decreases
Solution Approach 1:
The screen structure is segmented into multiple layers that can be manufactured and formed separately. This segmentation allows each layer to be formed into the required curved shape using standard forming processes before assembly, avoiding the need to form the entire thick-walled structure in one piece. The segmented approach maintains wear resistance while preserving formability for curved geometries.
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
The sieve effectively reduces impurity content, maintains high throughput, and extends service life while being more economical to produce, with improved wear resistance and reduced risk of clogging.
Implementation Method 1
When the shaft 5 rotates (arrow 11), the flails 9 are forced into an approximately radial alignment by the centrifugal force, as a result of which they press the pieces of raw material 13 against the outer surface 15 with the screen 16 of the housing 3 and push them away
Implementation Method 2
The particles of a size smaller than the hole diameter 18, which are produced by the crushing of the raw material by the flails 9, pass through the sieve 16
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The sieve (16) has an inner perforated plate (25) comprising a highly wear-resistant steel and an outer perforated plate (26) containing a medium-strength steel, where the inner and outer plates have matching holes and joined together to form a metal composite in order to provide a screen with small holes (27). The distance between the holes of the inner screen plate is large as thickness (S) of metal compound of the screen. The inner and outer plates are connected through a permanent connection by one of welding, screws, rivets, and bonding processes.