Adjustable Duct for Combine Harvester Fan Airflow Control
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Solution Overview
Problem
Current combine harvesters' cleaning systems face challenges in adjusting air flow volume and pressure effectively through ducts, leading to inadequate separation of grains and material other than grain (MOG), as existing adjustable deflectors fail to restrict air flow adequately.
Innovation Solution
Incorporating an hour-glass shaped duct with movable surfaces that can adjust the throat size to control air flow volume and pressure, using resilient materials and actuators to dynamically alter the duct's profile, allowing for precise regulation of air distribution between sieves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If adjustable deflectors are used to change air flow direction, then air flow direction can be adjusted, but air flow volume restriction is inadequate
Solution Approach 1:
The duct incorporates movable walls that can dynamically adjust their position to change the cross-sectional area of the duct passage. This dynamic adjustment allows the system to control both air flow direction and volume by moving the walls to different positions, resolving the contradiction between directional control and volume restriction.
Solution Approach 2:
The invention changes the geometric parameters of the duct by introducing movable walls that alter the duct's cross-sectional area. By adjusting the position of these walls, the system can modify both the direction and volume of air flow, thereby resolving the limitation of fixed deflectors that could only change direction without restricting volume.
2Ease of manufacture
If fixed duct geometry is used, then manufacturing is simple, but air flow volume and pressure cannot be regulated
Solution Approach 1:
The duct transitions from a fixed geometry to a dynamic structure with movable walls. These walls can be positioned at different locations along the duct to adjust the passage cross-sectional area, enabling regulation of air flow volume and pressure while maintaining a relatively simple manufacturing process for the duct structure itself.
Solution Approach 2:
The duct is segmented into sections with movable walls that can be independently adjusted. This segmentation allows different portions of the duct to be optimized for manufacturing simplicity while the movable sections provide the necessary adaptability for air flow regulation.
3Quantity of substance
If hour glass shape is formed in duct throat, then air flow volume is restricted, but duct complexity increases
Solution Approach 1:
Instead of forming a fixed hour glass shape that creates complex geometry, the invention uses movable walls to dynamically create the necessary restriction. The walls can be positioned to form an hour glass shape when needed, but are otherwise simple planar surfaces, thereby reducing overall duct complexity while maintaining the ability to restrict air flow volume when required.
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 air pressure and flow control, improving the separation efficiency of grains and MOG by adjusting the air flow volume and pressure, optimizing the cleaning process in combine harvesters.
Implementation Method 1
forming an hour glass shape in the throat area of one duct greatly affects the volume of air flow through that duct
Implementation Method 2
movable surfaces that can adjust the throat size to control air flow volume and pressure, using resilient materials and actuators to dynamically alter the duct's profile
Data Source
AI summary
A cleaning system for a combine harvester includes a fan, at least one duct having an interior passageway that is positioned to receive an air stream from the fan, and a surface defined within the interior passageway of the at least one duct that is configured to restrict a volume of the flow of air passing through the at least one duct and increase a pressure of the air stream passing through the duct.