Post-Accelerator for Combine Harvester Straw Distribution
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Solution Overview
Problem
Existing crop residue chopping and distribution arrangements for combine harvesters have limited distribution width due to exclusive reliance on straw deflectors for lateral deflection, resulting in inefficient spreading of chopped material across the field.
Innovation Solution
Incorporating a post-accelerator downstream of the straw chopper with displaceable conveyor elements that can be rotated to provide an outward velocity component to the chopped material, enhancing distribution width and improving material flow by forcing air through the chopper housing, while the straw guide plates assist in further lateral deflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If only straw deflectors are used for lateral deflection of chopped material, then the device complexity is low, but the distribution width is limited
Solution Approach 1:
The post-accelerator is integrated within the straw chopper housing, with conveying elements nested within the rotor assembly. This allows the additional acceleration function to be incorporated without significantly increasing external dimensions or overall device complexity, while still achieving wider material distribution through the combined effect of chopping and post-acceleration
Solution Approach 2:
The post-accelerator conveying elements serve multiple functions: they accelerate the chopped material outward to increase distribution width, and simultaneously work within the existing housing structure. This multi-functionality allows the system to achieve wider distribution without adding separate dedicated deflection mechanisms
2Area of stationary object
If the post-accelerator conveying elements are angled outward, then the distribution width increases, but the manufacturing precision requirements increase
Solution Approach 1:
The conveying elements have different geometric configurations at different locations: the leading surfaces are angled outward at acute angles to provide lateral acceleration for wider distribution, while the trailing surfaces are configured to match the housing contours. This local differentiation optimizes performance while the modular design allows these varied geometries to be manufactured as standardized components
Solution Approach 2:
The conveying elements are designed to work dynamically with the rotating rotor, where the angled leading surfaces interact with chopped material during the acceleration phase. The geometry is optimized for the dynamic conditions of rotation and material ejection, allowing functional precision to be achieved through operational dynamics rather than requiring extremely tight manufacturing tolerances
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
Significantly increases the distribution width of chopped crop residues with minimal effort, optimizing the chopping and conveying processes by separating them spatially and reducing the reliance on straw deflectors for lateral deflection, thereby improving the overall efficiency of the distribution.
Implementation Method 1
The post-accelerator has conveying elements which can be rotated about an axis of rotation oriented parallel to the axis of rotation of the straw chopper, at least some of which comprise leading surfaces which enclose an acute angle directed outwards with the axis of rotation of the post-accelerator
Data Source
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AI summary
The arrangement (36) has straw guide plates (72) arranged downstream to a post-accelerator (54) for lateral deflection and wide distribution of chopped material over a field (54). The accelerator includes conveying elements (60, 60', 60'') movable in a rotation around a rotation axis, which is oriented parallel to a rotation axis of a straw shredder (40). A portion of running surfaces of the conveying elements has a point, outward angle (alpha) with the former rotation axis to provide outwardly directed velocity components to shredded particles that are discharged from the accelerator.