Smoke Extraction Fan With Sinusoidal Blade Spacing
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Solution Overview
Problem
Existing smoke and vapour extraction fans face challenges in achieving high fluid dynamic efficiency, leading to low energy efficiency, increased noise, and high production costs due to complex geometries and component assembly issues, which result in reduced volumetric throughput and increased energy consumption.
Innovation Solution
A fan design featuring a diffuser with an impeller having blades arranged at variable distances, integrated with a compact diffuser structure and a one-piece motor shaft, optimizing air flow and reducing noise through sinusoidal blade spacing, and an increasing cross-section diffuser design to minimize head losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional fan designs with complex geometries are used to improve fluid dynamic efficiency, then energy efficiency improves, but manufacturing costs increase due to complex moulds and assembly
Solution Approach 1:
The patent integrates the motor shaft directly with the impeller to create a one-piece component, eliminating the need for separate coupling mechanisms and reducing assembly complexity. The diffuser is designed with an integrated structure that combines the motor housing, impeller housing, and discharge conduit into a single manufactured piece, thereby simplifying manufacturing while maintaining fluid dynamic efficiency
Solution Approach 2:
The patent optimizes geometric parameters of the diffuser and impeller through systematic variation of blade angles, diffuser vane configurations, and cross-sectional area gradients. These parameter optimizations achieve high fluid dynamic efficiency using standard manufacturing capabilities, avoiding the need for complex custom moulds while improving energy efficiency
2Productivity
If impellers with complex blade distributions are used to optimize fluid dynamic performance, then volumetric throughput improves, but noise increases due to turbulent vortices
Solution Approach 1:
The patent applies different blade distribution patterns to different sections of the impeller. The blades are arranged with variable spacing where the angular distance between adjacent blades varies according to a sinusoidal function, creating regions of different flow characteristics that reduce turbulent vortices while maintaining high volumetric throughput
Solution Approach 2:
The patent employs curved and sinusoidal blade profiles instead of straight radial blades. The blades follow smooth curved paths that guide airflow more gradually, reducing turbulence and vortex formation. The diffuser vanes also follow curved trajectories to smoothly transition flow from the impeller to the discharge conduit, minimizing noise-generating turbulence
3Volume of moving object
If the distance between fat-trap filters and fan extraction cross-section is reduced to compact the hood, then hood size decreases, but overall efficiency deteriorates due to adverse geometric effects
Solution Approach 1:
The patent repositions the motor and impeller assembly in three-dimensional space within the hood structure. The motor is mounted on the diffuser with its shaft extending axially through the impeller, allowing compact arrangement that maintains adequate flow paths. The diffuser is designed with an optimized three-dimensional geometry that provides sufficient development length for the air flow while minimizing the overall hood volume
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 enhances fluid dynamic efficiency, reduces noise, and lowers production costs by simplifying the fan's construction and assembly, resulting in a more efficient and quieter extraction system with improved volumetric throughput and energy performance.
Implementation Method 1
an impeller (3) having a body (20) with a plurality of blades (33) arranged at variable distances from each other, wherein said distance varies according to a sinusoidal function
Implementation Method 2
a diffuser (2) with an increasing cross-section from an inlet to a delivery conduit (5) from said diffuser (2) to its outlet (6)
Data Source
AI summary
A fan (1) for a smoke and/or vapor extraction system that includes an impeller (3) located within a diffuser or volute (2), the impeller (3) being driven by an electric motor (24); the impeller (3) having a body (20) having a flat part (21) from which a plurality of radially arranged blades (33) extend; these blades are separated from each other by a variable distance based on a periodic function. In addition to this, the diffuser (2) has an air delivery or discharge conduit (5) having a cross-section increasing from an inlet to its outlet (6).