Air Guide Element Deflects Flow for Combine Harvester Cleaning
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Solution Overview
Problem
Current cleaning devices for combine harvesters face challenges in efficiently separating grain from chaff due to turbulence and non-homogeneous air flows, which affect the effectiveness of the separation process.
Innovation Solution
The implementation of a cleaning device with a drop step subjected to an obliquely upwards and backwards air flow, facilitated by a separate angular and/or concavely curved air guide element in the air duct, ensures improved separation by deflecting the air flow without significant turbulence, allowing contaminants to be blown upwards and grain to fall due to gravity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a horizontal air duct is used to supply air flow to the drop step, then the air flow can be delivered to the separation area, but turbulence and non-homogeneous air flow occur which reduce separation effectiveness
Solution Approach 1:
An air guide element is introduced as an intermediary component between the air duct and the drop step. This guide element has a specific geometry (angular and/or concavely curved) that actively shapes and directs the air flow, transforming it from a turbulent horizontal flow into a controlled obliquely upward and backward flow. The guide element mediates the transition and ensures homogeneous air flow distribution across the drop step surface, thereby improving separation effectiveness without requiring complex duct redesigns.
2Reliability
If the air flow is directed horizontally from the fan, then the duct structure is simple, but the air flow does not effectively separate grain and contaminants at the drop step
Solution Approach 1:
The air guide element serves as a relatively simple intermediary component that can be integrated into the existing duct structure. Its angular and/or concavely curved geometry provides the necessary flow direction change from horizontal to obliquely upward and backward without requiring complete duct redesign. This maintains structural simplicity while achieving the required flow pattern for effective separation.
Solution Approach 2:
The air guide element employs concave curvature in its design to smoothly redirect the air flow. The curved surface guides the air molecules in a controlled manner, preventing turbulence and ensuring homogeneous flow distribution. This curved geometry is more effective than sharp angular transitions and helps maintain flow stability while achieving the desired oblique upward and backward direction.
3Reliability
If no air guide element is used, then the device structure is simpler, but turbulence forms at the drop step reducing cleaning performance
Solution Approach 1:
The air guide element is positioned as an intermediary component within the air duct system, integrated in a manner that adds minimal structural complexity. It acts as a flow conditioning element that can be manufactured as a single piece or modular components, allowing easy installation and adjustment. The element's primary function is to condition the air flow before it reaches the drop step, ensuring turbulence-free operation while maintaining overall device simplicity.
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
This solution enhances the separation efficiency by ensuring a turbulence-free, controlled air flow that effectively separates grain and contaminants, improving the overall cleaning process in combine harvesters.
Implementation Method 1
At least one separate, preferably angular and/or concavely curved air guide element is arranged in the region of the duct directly adjacent to the drop step, which deflects the horizontal air flow coming in from the fan obliquely upwards and backwards during operation.
Implementation Method 2
The upward velocity component of the airflow provides improved separation of grain and contaminants at the drop stage because the contaminants are not only blown backwards but also to some extent upwards while the grain falls down due to gravity.
Data Source
Figure 1
Figure 2
AI summary
A cleaning device (46) for a combine harvester (10) comprises a conveyor floor (40) to the upper surface of which a mixture of grain and chaff can be fed during operation, a drop step (86) arranged at a rear end of the conveyor floor (40), and a blower (62) connected to the drop step (86) by an air channel (82). Within the area of the channel (82) directly adjacent to the drop step (86), a separate air guide element (114) is arranged, which deflects a horizontal airflow entering from the blower (62) obliquely upwards and backwards during operation.