Tandem Diffuser Blade Fan Design for Extended Throw Distance
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Solution Overview
Problem
Existing fan units face limitations in increasing throw distance due to the small safety distance between the contact protection and the fan, which restricts efficiency and compliance with Ecodesign Directive requirements, while also hindering the ability to achieve high throw distances.
Innovation Solution
The implementation of an additional guide device with guide vanes arranged on a rod-shaped carrier, attached to the protective grille, which allows for adjustable throw distances and improved airflow alignment, enabling higher throw distances while maintaining safety and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If guide vanes are installed downstream of the protective guard to increase throw distance, then the throw distance increases, but the safety distance between the protective guard and the fan must be reduced, which reduces fan unit efficiency
Solution Approach 1:
Instead of placing the guide vane inside the protective guard (which would require small ring spacing), the guide vane is inverted to be placed outside the protective guard. This reversal of the conventional arrangement allows the guide vane to extend the throw distance while the protective guard maintains its standard, more efficient ring spacing configuration.
Solution Approach 2:
The guide vane is designed to extend axially beyond the protective guard in the direction of airflow. This dimensional extension into the downstream space allows the guide vane to function effectively in reducing swirl and directing airflow axially, thereby increasing throw distance without interfering with the protective guard's optimal ring spacing.
2Length of moving object
If guide vanes are used to increase throw distance, then the throw distance increases, but the design must be customized for each fan size and protective grille type, increasing device complexity
Solution Approach 1:
The guide vane is designed with a universal mounting structure that can be adapted to different protective grille types and fan sizes. The guide vane includes mounting features that can interface with various protective grille configurations, allowing a single guide vane design to serve multiple fan unit variants, thereby reducing the need for customized guide vanes for each fan size.
3Reliability
If the ring spacing of the protective guard is reduced to maintain safety distance, then safety compliance is achieved, but the fan unit efficiency and throw distance are reduced
Solution Approach 1:
The conventional arrangement is inverted by placing the guide vane outside the protective guard rather than inside. This allows the protective guard to maintain larger, more efficient ring spacing for both safety compliance and fan efficiency, while the guide vane positioned downstream still achieves the throw distance extension through its axial airflow guidance function.
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 significantly enhances the throw distance of fan units, improves airflow distribution, and allows for compliance with Ecodesign Directive requirements, while also providing a cost-effective and simple retrofit option for existing units.
Implementation Method 1
These guide vanes reduce swirl and thus direct the airflow axially, thereby increasing the throw distance
Implementation Method 2
The additional guide vane significantly increases the throw distance of the fan unit according to the invention
Data Source
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AI summary
The fan unit has at least one fan housed in a housing (14). Provided in the housing (14) is a guide vane (23) assigned to the fan and having guide vanes (21) distributed over the circumference. A further guide device is assigned to the guide device (23), which lies in the flow path of the sucked-in air. With the additional guide vane, the range of the fan unit can be significantly increased, so that the requirements set by the Ecodesign Directive can be met without any problems.