Combine Harvester Airflow Segmentation for Cleaning Loss Reduction
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Solution Overview
Problem
The existing combine harvester's cleaning performance is hindered by additional air flows that are directed opposite to the grain separation direction, leading to increased cleaning losses due to grains being discharged with non-grain components, and the air flow does not effectively target the second fall stage between the conveyor floor and the upper sieve.
Innovation Solution
An air outlet opening is directed towards the first fall stage, providing an air flow that removes lighter non-grain components like chaff or short straw before they reach the conveyor floor, reducing the load on the cleaning device and enhancing grain purity and throughput by partially removing these components before they reach the upper sieve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If an air duct with air outlet opening on the underside of the return floor is used to provide additional air flow, then cleaning performance is improved, but grain is discharged over the upper sieve together with non-grain components leading to increased cleaning losses
Solution Approach 1:
The air flow system is segmented into two distinct functions: the cleaning fan provides air flow through the upper and lower sieves for cleaning, while a separate air outlet opening on the return floor provides additional air flow to support crop material. This segmentation prevents the harmful mixing of air flows and their adverse effects on grain discharge.
Solution Approach 2:
The return floor acts as an intermediary element that distributes crop material while being subjected to additional air flow from the air outlet opening. This intermediary structure enables the additional air flow to support crop material without directly interfering with the cleaning air flow through the sieves, thus preventing grain from being discharged with non-grain components.
2Productivity
If the air outlet opening is aligned on the upper sieve to provide additional air flow, then cleaning performance is improved, but the additional air flow is directed opposite to the separation direction of grains from material flow
Solution Approach 1:
Instead of directing the air outlet opening towards the upper sieve where it would create harmful counter-flow, the air outlet is inverted to open on the return floor above the conveyor floor. This inversion redirects the additional air flow to support crop material in the opposite direction, preventing it from opposing the grain separation direction and eliminating the harmful effect.
3Quantity of substance
If the air flow is directed in the opposite direction to the separation direction of grains, then additional air flow is provided, but grain is discharged over the upper sieve together with non-grain components
Solution Approach 1:
The additional air flow is locally applied to the return floor area where crop material is supported, rather than being uniformly distributed. This localized application ensures that the air flow supports crop material where needed without interfering with the grain separation process at the upper sieve, preventing grain from being discharged with non-grain components.
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 efficiency by reducing the load on the sieves due to non-grain components, increasing grain purity and throughput, and optimizing the air flow to effectively separate lighter components from the grain stream.
Implementation Method 1
an air flow LS directed towards the first fall stage 17 emerges from the at least one air outlet opening 21, which has the particular effect that the lighter non-grain components such as chaff or short straw are partially removed from the crop stream
Implementation Method 2
a first fall stage 17 is formed between the return floor 11 and the conveyor floor 9, along which crop material moves from the return floor to the conveyor floor in free fall
Implementation Method 3
a second fall stage 18 is formed between the conveyor floor 9 and the upper sieve 13, along which crop material arrives from the conveyor floor 9 in free fall onto the upper sieve 13
Data Source
Figure 1
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AI summary
The present invention relates to a combine harvester (1) comprising a threshing device (2), a conveying floor (9) arranged below the threshing device (2), a separating device (3) arranged downstream of the threshing device (2), a return floor (11) arranged below the separating device (3), which is arranged in a plane above the conveying floor (9) so that a first drop stage (17) is formed, along which crop material falls at least partially from the return floor (11) onto the conveying floor (9) in free fall, a cleaning device (4) comprising a cleaning blower (12) and at least one upper sieve (13) and a lower sieve (3), the sieve plane of which lies on a plane below the conveying floor (9) so that a second drop stage (18) is formed, along which crop material falls freely from the conveying floor (9) onto the upper sieve (12), and a control device (29).wherein at least one air outlet opening (21) is provided at the end of at least one air guide duct (19), from which an airflow (LS) directed towards the first drop stage (17) exits.