Chaff Spreader Cross-Blown Airflow Plenum Design
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Solution Overview
Problem
Current chaff spreaders on agricultural harvesters face challenges in effectively distributing chaff due to its low density and high air resistance, with existing designs struggling to achieve a wide and uniform spread, especially when attempting to mix chaff with an air stream.
Innovation Solution
A spreader arrangement featuring a pair of counter-rotating spreader units with pneumatic sources and impellers, where airflow from one unit is routed to the other to create a controlled laminar flow, allowing chaff to be entrained in a shaped airflow for efficient lateral distribution, reducing the risk of nozzle clogging and requiring only one pair of hydraulic motors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If an air stream is introduced to entrain chaff in the spreader, then chaff distribution width is improved, but air bleeding out of the fan causes uncontrolled chaff blowing and reduces spreading precision
Solution Approach 1:
A plenum chamber is introduced as an intermediary component between the fan and the environment. The plenum captures and controls the air stream from the fan, directing it through a structured outlet arrangement rather than allowing uncontrolled bleeding. This mediator enables the air to entrain chaff effectively while maintaining precise control over the spreading pattern.
Solution Approach 2:
The air flow parameters are changed by routing the air through a plenum chamber that regulates pressure and flow direction. The outlet arrangement modifies the air stream characteristics, transforming uncontrolled bleeding into a controlled air curtain that enhances chaff distribution width while maintaining spreading precision.
2Stability of the object's composition
If airflow is routed cross-wise between opposed impellers, then chaff mixing and dispersion is improved, but system complexity increases
Solution Approach 1:
The plenum chamber merges the air streams from both opposed impellers into a single controlled outlet arrangement. This combining approach achieves effective chaff mixing and dispersion by utilizing the interaction between the two air streams while simplifying the overall routing complexity through a unified plenum structure.
Solution Approach 2:
The cross-flow arrangement allows each impeller's air stream to naturally assist in expelling chaff from the opposite impeller. The system uses its own internal air streams to achieve enhanced mixing and dispersion without requiring additional external components or complex control mechanisms.
3Area of stationary object
If conventional spreader designs are used, then structure is simple, but chaff spread width is insufficient for customer demands
Solution Approach 1:
The invention utilizes pneumatic principles by employing a fan-driven air stream routed through a plenum chamber to create a controlled air curtain. This pneumatic system entrains chaff particles and propels them laterally, significantly increasing spread width beyond what mechanical spreaders alone can achieve.
Solution Approach 2:
The invention adds a pneumatic dimension to the traditional mechanical spreading system. By introducing air flow as a third dimension of action (in addition to mechanical impeller rotation), the system achieves extended chaff distribution width while maintaining a relatively simple overall structure.
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
The solution enables a more controlled and efficient distribution of chaff across a wider area, improving uniformity and reducing the risk of airflow losses, while minimizing the risk of nozzle clogging and reducing the number of hydraulic motors needed.
Implementation Method 1
airflow from the first unit pneumatic source to the vicinity of the second unit impeller to aid residue expulsion therefrom
Implementation Method 2
creating an airflow to assist in dispersing the crop residue
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A spreader for a harvesting machine (10) includes a pair of counter-rotating spreader units (18, 20) each having an impeller (26, 28, 64, 66, 104) and a fan (38, 40, 76, 78, 106) supported on a common shaft. A plenum (50, 80) routes at least part of the airflow from a first fan to merge with chaff exiting the opposite impeller and at least a part of the airflow from the opposite fan to merge with chaff exiting the impeller on the machine side of the first fan. In one embodiment all airflow from a fan is ducted (52, 54) to an impeller on the opposite side, while a second embodiment commingles airflow from both fans in a plenum (80) from which portions of the mixed airflows is directed to the chaff exiting each impeller exit. In a third, embodiment an established airflow receives chaff from the impeller (104) on the side on which that airflow is generated.