Multi-Row Axial Diffuser for Compact Vacuum Cleaner Airflow
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Solution Overview
Problem
Existing vacuum cleaners face inefficiencies due to complex production tools and boundary layer separation in long air channels of axial diffusers, leading to increased flow resistance and losses, particularly in compact designs like handheld models where size and energy efficiency are critical.
Innovation Solution
The vacuum cleaner features an axial diffuser with vanes arranged in multiple consecutive rows, promoting a stable boundary layer and smooth deceleration of air flow by interrupting the flow surface and increasing the cross-sectional area, thereby minimizing losses and enhancing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the air channels in the axial diffuser are made long to achieve smooth deceleration of air, then the deceleration becomes smoother and losses are reduced, but the production tools become extremely complex and manufacturing difficulty increases
Solution Approach 1:
The diffuser is divided into multiple rows of vanes (at least two rows) arranged consecutively in the axial direction. This segmentation allows the flow surface to be interrupted, creating multiple shorter effective channels instead of one long channel, thereby simplifying production tools while maintaining smooth deceleration through staged pressure recovery.
2Productivity
If the cross sectional area of diffuser passages is increased to reduce flow resistance, then air flow efficiency improves, but boundary layer separation occurs resulting in increased losses
Solution Approach 1:
The diffuser passages are segmented into multiple rows of vanes with interrupted flow surfaces. This creates multiple shorter diffusion paths that increase cross-sectional area progressively without causing boundary layer separation, as each row resets the boundary layer before the next expansion stage.
Solution Approach 2:
The diffuser utilizes the circumferential dimension by arranging vanes in multiple rows around the axial direction. This multi-row circumferential arrangement allows progressive area increase in a controlled manner, distributing the expansion across multiple dimensions rather than a single long linear path.
3Loss of energy
If radially arranged diffusers are used to increase efficiency, then deceleration performance improves, but the vacuum cleaner diameter increases making it less compact
Solution Approach 1:
The patent employs an axial diffuser with curved vane surfaces that follow the axial flow direction. The vanes are arranged to create smooth curved flow paths that decelerate air efficiently in the axial direction, maintaining a compact cylindrical form factor while achieving effective diffusion through optimized curved geometries.
4Loss of energy
If vanes are arranged in multiple consecutive rows in the axial direction, then flow surface interruption promotes stable boundary layer and reduces separation, but device complexity increases
Solution Approach 1:
The diffuser is segmented into multiple rows of vanes (at least two rows) arranged consecutively in the axial direction. Each row contains vanes that extend between the inner and outer circumferential walls. This segmentation interrupts the flow surface, creating fresh boundary layers in each row that remain stable and attached, preventing separation while the modular row structure keeps manufacturing complexity manageable.
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 configuration reduces unwanted air flow separation and energy losses, achieving a more compact and efficient fan system with improved airflow distribution and reduced power requirements, suitable for both upright and handheld models.
Implementation Method 1
The air stream will follow the interrupted flow surface for a longer distance compared to a non-interrupted surface of the same length since the transition between the rows will promote a stable boundary layer along the vanes of the downstream row
Implementation Method 2
unwanted separation of the air flow from the flow surface will be avoided
Implementation Method 3
a diffuser is present for deceleration of air ejected from an impeller in a controlled manner, in this way transforming the dynamic pressure created by the impeller into static pressure
Data Source
Figure 1
Figure 2
Figure 3a~3b
AI summary
A vacuum cleaner comprising an electric motor, an impeller and an axial diffuser arranged on a common axis is provided. The impeller is connected to the electric motor and is arranged for rotation on the common axis to achieve a radial air flow. The radial air flow is redirected into an axial air flow. The diffuser passages are arranged between an inner circumferential wall and an outer circumferential wall, wherein the walls are coaxially arranged around the common axis. Each diffuser passage is delimited in a circumferential direction between the walls by vanes extending between the inner wall and the outer wall and in an axial direction extending substantially in parallel with the common axis. The vanes are arranged in at least two rows being consecutively arranged in the axial direction extending substantially in parallel with the common axis.