Asymmetric Chaffer Channels for Hillside Grain Distribution
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Solution Overview
Problem
Conventional combine harvesters face inefficiencies in grain distribution and cleaning on hillside conditions, leading to compromised performance and increased risk of grain loss, due to grain bouncing and uneven distribution across the chaffer.
Innovation Solution
The chaffer features longitudinal channels with asymmetric non-planar surfaces, concentrating grain towards the center and increasing the operational surface area, ensuring grain remains in contact with the channel surface despite lateral tilts, and includes a fan for airflow to lift discardable parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional planar chaffer channels are used, then the structure is simple and easy to manufacture, but grain bounces off the surface and distributes unevenly on hillside conditions
Solution Approach 1:
The chaffer channel cross-section is designed with an asymmetric non-planar surface where the downhill side has a greater surface area than the uphill side. This asymmetry compensates for the lateral tilt effect on hillside conditions, causing grain to settle more evenly across the channel width rather than bouncing to one side.
Solution Approach 2:
The chaffer channel surface is designed with a curved non-planar profile rather than a flat surface. This curvature increases the surface area and creates a more effective grain-contact surface that maintains grain retention and distribution under varying operational conditions including hillside tilts.
2Manufacturing precision
If the cleaning airstream speed is increased to improve grain cleanliness, then lighter material is better separated, but grain loss increases due to grain being carried out of the rear
Solution Approach 1:
The asymmetric non-planar chaffer surface performs preliminary grain concentration and settling before the material reaches the cleaning airstream. By pre-distributing grain evenly and keeping it settled on the chaffer surface, the system allows for more precise control of the cleaning airstream speed, achieving good separation without excessive grain loss.
3Manufacturing precision
If active levelling devices are used to compensate for hillside conditions, then grain distribution is maintained, but the device complexity and cost increase
Solution Approach 1:
The asymmetric non-planar chaffer channel design provides self-compensating grain distribution without requiring external active levelling devices. The geometric asymmetry inherently counteracts the lateral tilt effect, allowing the chaffer to self-regulate grain distribution under hillside conditions without additional complex mechanical systems.
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 design enhances grain distribution and retention on the chaffer, leading to improved efficiency and reduced grain loss during sidehill operations, maintaining effective cleaning and distribution to the lower sieve.
Implementation Method 1
a fan operable to cause an air flow through said chaffer for lifting up discardable part from the crop material and transporting it out of the combine harvester
Implementation Method 2
the crop material will remain in contact with the surface of the channel despite the lateral tilt
Data Source
AI summary
A cleaning mechanism of a combine harvester, for cleaning threshed and separated crop material, including a grain pan for receiving threshed and separated crop material and transporting the crop material rearwardly; a chaffer installed proximate the grain pan for receiving material from the grain pan where the chaffer includes a plurality of longitudinal channels with non-planar surfaces giving each channel a curved or trapezoidal cross section and at least two of the chaffer channels have an asymmetric non-planar surface with a greater part of the surface area facing the side portions of the chaffer; and a fan that causes an air flow through the chaffer to lift up discardable parts from the crop material and transport the discardable parts out of the combine harvester.