Mixed Flow Fan Hub Design for Fruit Harvester Cleaning
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Solution Overview
Problem
Centrifugal cleaning fans used in fruit harvesters are noisy and lack mass flow characteristics, posing a disturbance in residential areas and inefficient in separating larger Material Other than Grapes (MOG) from the crop stream.
Innovation Solution
The implementation of a mixed flow fan system with a frustoconically shaped hub and blades that curve from the inlet to the outlet, allowing both axial and radial air flow, combined with intake ducts and optional material shredders, to enhance air pressure and flow rate while reducing noise and power requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If a centrifugal fan is used for cleaning, then pressure increase characteristics are improved, but mass flow characteristics deteriorate
Solution Approach 1:
The patent changes the fundamental operating parameters of the fan by transitioning from a centrifugal design to an axial fan design. This parameter change fundamentally alters the flow characteristics, achieving high mass flow rates while maintaining adequate pressure increase through the axial flow configuration and large diameter design.
2Stress or pressure
If a centrifugal fan is used for cleaning, then pressure increase characteristics are improved, but noise level worsens
Solution Approach 1:
The patent changes the fan type parameter from centrifugal to axial, which fundamentally alters the noise generation characteristics. The axial fan design with large diameter and high speed rotation produces lower noise levels compared to centrifugal fans, while still achieving the required pressure increase through optimized blade geometry and airflow path.
3Stress or pressure
If a centrifugal fan is used for cleaning, then pressure increase characteristics are improved, but power consumption worsens
Solution Approach 1:
The patent changes the fan configuration parameter from centrifugal to axial type, which improves the power efficiency for achieving the same pressure increase. The axial fan with large diameter and optimized blade design reduces the power consumption required to generate the necessary air pressure for cleaning operations.
4Reliability
If the fan is positioned above the cleaning area, then cleaning effectiveness is improved, but discharge direction becomes restricted
Solution Approach 1:
The patent makes the discharge system multi-functional by incorporating adjustable discharge chutes that can redirect the airflow in different directions. This allows the fan positioned above the cleaning area to maintain its effective cleaning position while providing versatile discharge direction control to accommodate different operational requirements and discharge MOG to various locations.
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 mixed flow fan system effectively removes larger MOG with improved mass flow and pressure characteristics, reducing noise and operational costs, and ensures efficient separation and discharge of crop materials.
Implementation Method 1
Each of the blades curves from the inlet end toward the outlet end, relative to a direction of rotation of the rotor, whereby air is blown during operation both axially and radially
Implementation Method 2
The at least one cleaning fan is configured as a mixed flow fan... the hub including a smaller diameter inlet end and a larger diameter outlet end
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A cleaning fan system (200, 300, 500, 600, 700) for use in a fruit harvester includes at least one cleaning fan (100) having an inlet (114) and an outlet (116). The cleaning fan system (200, 300, 500, 600, 700) is characterized in that the at least one cleaning fan (100) is configured as a mixed flow fan with a rotor (106) having a frustroconical shaped hub (124) and a plurality of blades (126). The hub (124) includes a smaller diameter inlet end (128) and a larger diameter outlet end (130). Each blade (126) is attached to the hub (124) and curves forward from the inlet end (128) toward the outlet end (130), relative to a direction of rotation (132) of the rotor (106), whereby air is blown during operation both axially and radially. At least one intake duct (202, 302, 502, 602, 702) includes at least one inlet (204, 304, 504, 604, 704) and an outlet (206, 306, 506, 606, 706). Each inlet (204, 304, 504, 604, 704) is positioned in association with an area to be cleaned on the fruit harvester, and the outlet (206, 306, 406, 506, 606, 706) is coupled with an inlet (114) of a corresponding cleaning fan (100).