Air Guide Element Curvature for Combine Harvester Sieve Flow
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Solution Overview
Problem
The existing cleaning devices for combine harvesters face inefficiencies in the fluidized bed phase of grain separation, leading to reduced separation quality and effectiveness, particularly in the rear sieve area where the air flow decreases, resulting in a shorter fluidized bed phase and less effective segregation.
Innovation Solution
The implementation of air guide elements with specific cross-sectional shapes and adjustable inclinations below the upper and lower sieves redirects the air flow to maintain a longer fluidized bed phase, enhancing the separation efficiency by ensuring consistent air flow through the sieves and minimizing slipstream effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If air baffles with sharp-edged sections are used to deflect air flow, then air flow deflection is improved, but flow separation and slipstream effects increase
Solution Approach 1:
The patent applies curvature principle by replacing sharp-edged air baffles with air guide elements that have curved surfaces. The end faces and side surfaces of the air guide elements are designed with specific radii of curvature to guide air flow smoothly around the elements, preventing flow separation and slipstream effects while maintaining effective air flow deflection for fluidized bed phase extension
2Manufacturing precision
If the fluidized bed phase is extended in the discharge direction, then separation quality is improved, but the device length increases
Solution Approach 1:
The patent applies parameter changes principle by modifying the air flow parameters through specially shaped air guide elements. By changing the geometry parameters (radii of curvature) of the air guide elements, the air flow is redirected to maintain fluidized bed conditions over a longer distance, effectively extending the fluidized bed phase without proportionally increasing the overall device length
3Reliability
If air flow is directed obliquely from below towards the sieves, then fluidized bed phase is created, but air flow decreases in the rear sieve area
Solution Approach 1:
The patent applies intermediary principle by introducing air guide elements as intermediate components between the air source and the sieves. These air guide elements act as mediators that redirect and distribute air flow, ensuring that sufficient air flow reaches the rear sieve areas to maintain the fluidized bed phase throughout the entire sieve length
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 improves the cleaning effect by extending the fluidized bed phase, increasing the separation quality and reducing contamination of grains with chaff or short straw, allowing for better utilization of available space and adaptability to varying operating conditions.
Implementation Method 1
The special cross-sectional shape of the air guide elements results in the effect that the air flow generated by the fan flows around the respective air guide element on both sides, with the air flow experiencing a different deflection through the respective air guide element on the bottom side than on the top side.
Implementation Method 2
The sieve arrangement is driven in an oscillating manner, with the oscillating movement serving to convey and loosen the crop on the sieves.
Implementation Method 3
A loosened, fluidized bulk layer forms on the sieve, in which the coherence of the individual particles is lost and the grains sink onto the sieve in a short time
Implementation Method 4
In the flight phase, separation due to gravity is essentially caused in the flow of material itself.
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The present invention relates to a cleaning device (4) for a combine harvester (1), comprising at least one blower (13), an oscillatingly driven sieve frame having at least one upper sieve (14) and one lower sieve (15) spaced apart from each other in the sieve frame, and at least one channel section (28) that directs an airflow provided by the blower from obliquely below towards the underside of the upper sieve and the lower sieve, wherein at least one air guide element (32, 40) is arranged below the lower sieve (15) and the upper sieve (14), which has opposing end faces (34, 42) free of tapered areas and at least one side face (33, 41) connecting them, which have different radii of curvature (R1, R2, R3) with respect to the cross-sectional center (M) of the air guide element (32, 40), wherein the The radii of curvature (R1, R3) of the end faces (34, 42) are larger,as the radius of curvature (R2) of at least one side surface (33, 41).,