Screw Separation Platforms With Double-Start Thread Control
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Solution Overview
Problem
Existing sorting systems face issues with long parts passing through gaps between shafts when dropping from a higher to a lower level, leading to inefficiencies and material wrapping around shafts.
Innovation Solution
A mechanical separation system using auger screws with a combination of double-start and single-start thread screws, inclined platforms, and a curtain of suspended elongated members to manage material flow and prevent long parts from passing through gaps, while ensuring efficient sieving and separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If materials drop from a higher level to a lower level on a conveyor, then material flow speed increases, but long parts pass through the gap between shafts causing sorting errors
Solution Approach 1:
The screw is divided into multiple sections along its axis, with each section having a different number of threads (e.g., first section with two threads, second section with three threads). This segmentation allows different parts of the same screw to handle different material types and flow rates, preventing long parts from passing through gaps while maintaining high-speed flow for appropriate materials.
Solution Approach 2:
Different sections of the screw are assigned different local qualities in terms of thread configuration. The first section has a coarser pitch suitable for bulk material flow, while the second section has a finer pitch for controlling long parts. This local differentiation resolves the contradiction by optimizing each section for its specific function.
2Device complexity
If traditional disc screens with shafts are used, then simple structure is achieved, but material wraps around shafts causing operational issues
Solution Approach 1:
Instead of using traditional disc screens where material can wrap around central shafts, the invention inverts the approach by using auger screws that convey material along their length. The spiral geometry of the auger prevents material from wrapping around the shaft, as material is contained within the spiral flights and moved forward by the rotating screw.
3Ease of manufacture
If uniform thread pitch is used on all screws, then manufacturing simplicity is maintained, but sieving efficiency for different material sizes is reduced
Solution Approach 1:
The screw thread is segmented into multiple sections with different pitch values along the axial direction. This allows the screw to handle multiple material sizes and types simultaneously, improving sieving efficiency without requiring multiple separate screws or complex assembly procedures.
Solution Approach 2:
The pitch parameter of the screw thread is changed along its length to optimize performance for different material characteristics. The first section has a first pitch value optimized for one type of material flow, while the second section has a second pitch value optimized for another type, allowing a single screw to perform multiple sieving functions.
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 system effectively prevents long parts from passing through gaps and enhances sieving efficiency by maintaining material agitation and separation quality, potentially eliminating the need for additional feeding conveyors and improving material retention.
Implementation Method 1
a platform (11a, 11b) comprising screws (20) providing a sieving surface for the materials to be sieved as the materials travel thereon, the screws each comprising a screw axis (32), the axes of the screws (20) being parallel and neighbor to one another, the screws (20) adapted to undergo a rotational movement
Implementation Method 2
the screws having a screw inclination along the screw axis resulting in a free end of the screws being higher than a supported end of the screws
Data Source
AI summary
A system for mechanical separation of materials comprising at least two platforms, each comprising screws undergoing a rotational movement, wherein the screws have a proximal end and a distal end, the distal end being free, wherein the screws of a first one of the at least two platforms all have a first inclination from the proximal end thereof to the distal end thereof; wherein the screws of a second one of the at least two platforms all have a second inclination from the proximal end thereof to the distal end thereof; the first inclination being different from the second inclination. The at least two platforms form a drop in-between along the main direction of travel. There is a double-start thread screw by the drop on the downstream platform that prevents long objects to pass through the screws and optionally a curtain of elongated members by the drop.