Harvester Cleaning Screen Movable Fan Airflow
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Solution Overview
Problem
Agricultural harvesters, such as sugarcane harvesters, face inefficiencies in removing trash from the flow of harvested crop due to the degradation of fan efficiency when dealing with high debris levels, leading to suboptimal separation of debris from clean billets.
Innovation Solution
A cleaning assembly positioned downstream of the chopper assembly, featuring a movable screen and fan configuration, where the fan generates airflow through the upstream side before the downstream side, effectively holding and removing trash from the screen as it moves along a travel path, maintaining efficiency and preventing clogging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a radial fan is used in the primary extractor assembly to remove trash from harvested crop, then the fan can effectively separate debris from billets under normal conditions, but the fan efficiency degrades significantly when high volumes of trash or debris flow through it
Solution Approach 1:
The cleaning assembly is divided into multiple screens arranged in series (first screen, second screen, third screen) that segment the trash removal process. Each screen handles a portion of the debris load, preventing any single fan from being overwhelmed by the total trash volume, thus maintaining fan efficiency while handling high debris quantities.
Solution Approach 2:
Multiple screens act as intermediaries between the high-volume debris flow and the fan. The screens capture and hold trash particles, allowing the fan to work with a reduced load of airborne debris rather than the full volume of trash, thereby maintaining fan efficiency under high debris conditions.
2Ease of manufacture
If a stationary screen is used in the cleaning assembly, then the structure is simple and easy to manufacture, but the screen becomes clogged with trash over time, reducing cleaning effectiveness
Solution Approach 1:
The screen is designed to be movable rather than stationary, capable of oscillating or moving back and forth across the airflow path. This dynamic motion prevents trash from accumulating and clogging the screen by continuously redistributing captured particles, maintaining cleaning effectiveness while keeping the structural design relatively simple.
Solution Approach 2:
The movable screen design allows the screen to self-clean by moving itself to dislodge accumulated trash. The motion of the screen through the airflow and against the trash buildup enables automatic clearing without requiring external cleaning mechanisms, maintaining reliability while avoiding complex additional systems.
3Productivity
If the fan is positioned to blow air through the cleaning assembly from upstream to downstream, then trash is effectively removed from the crop flow, but the screen requires continuous cleaning to prevent clogging
Solution Approach 1:
The screen's movable design, oscillating in response to airflow or mechanical actuation, provides self-cleaning capability that reduces the complexity of dedicated cleaning mechanisms. The dynamic motion allows the screen to clear itself during normal operation, maintaining high trash removal efficiency without requiring complex additional cleaning systems.
Solution Approach 2:
The screen cleaning function is integrated into the screen's own motion mechanism. As the screen moves back and forth during normal cleaning operation, it automatically clears accumulated trash, making the system self-sufficient and reducing the need for separate complex cleaning mechanisms while maintaining high productivity.
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 enhances trash removal efficiency, maintaining fan airflow capacity and reducing the need for secondary extractor assemblies by continuously cleaning the screen, ensuring clean billets are delivered to the elevator assembly with minimal debris.
Implementation Method 1
The fan is configured to generate a flow of air in a first direction such that the flow of air passes through the upstream side of the cleaning assembly before the downstream side of the cleaning assembly
Data Source
AI summary
A system for removing trash from a flow of harvested crop within an agricultural harvester may include a chopper assembly and a cleaning assembly downstream of the chopper assembly relative to the flow of harvested crop. An upstream side of the cleaning assembly may be positioned closer to the chopper assembly than a downstream side of the cleaning assembly. The cleaning assembly may include a screen and a fan, with the fan positioned at least partially between the upstream and downstream sides of the cleaning assembly. The fan may generate a flow of air in a first direction such that the flow of air passes through the upstream side before the downstream side of the cleaning assembly. Additionally, the screen may be movable along a travel path relative to the fan such that a portion of the screen is movable between the upstream and downstream sides of the cleaning assembly.