Electric Blower Sound Cover Annular Gap Design
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Solution Overview
Problem
Electric blowers face issues with noise emission and the risk of foreign particles being sucked in due to high inflow speeds, which can clog the air intake and increase noise levels.
Innovation Solution
A cover disk with a circumferential outer edge is used to form an annular gap between the disk and the fan spiral, reducing inflow speed and preventing particle ingestion, while an insulating element and specific design features like curvature and inclination further reduce noise emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a narrow inlet channel is used to supply air to the blower wheel, then the blower can achieve high flow velocities and efficient operation, but foreign particles are more likely to be drawn in and clog the air inlet
Solution Approach 1:
The inlet channel is transformed from a linear narrow passage to a three-dimensional voluminous space by introducing a hollow spherical body with multiple inlet openings distributed on its surface. This dimensional transformation allows air to enter from multiple directions and locations, effectively increasing the functional inlet area without compromising the blower's flow velocity requirements.
Solution Approach 2:
The single inlet channel is segmented into multiple inlet openings distributed across the surface of the spherical body. This segmentation allows the air intake function to be distributed across multiple locations, reducing the velocity requirement at each individual opening while maintaining overall air supply efficiency.
2Productivity
If the air inlet is exposed to the environment, then ambient air can be freely supplied to the blower wheel, but noise is directly emitted from the intake opening into the surroundings
Solution Approach 1:
A hollow spherical body is introduced as an intermediary element between the ambient environment and the blower wheel intake opening. This spherical intermediary contains the air inlet channels within its structure, allowing air to be supplied to the blower while preventing direct noise emission from the intake opening to the surroundings.
3Speed
If high flow velocities are maintained at the air inlet, then the blower operates efficiently, but foreign particles are more likely to be sucked in and cause clogging
Solution Approach 1:
The air intake system transitions from a one-dimensional narrow channel to a three-dimensional spherical structure with distributed inlet openings. This allows the same volumetric air flow to be achieved through multiple smaller openings, reducing the flow velocity at each opening and thereby reducing particle ingestion risk.
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 effectively minimizes noise emissions and reduces the risk of foreign particles being sucked in, resulting in a quieter and more reliable blower operation.
Implementation Method 1
a sound-absorbing element is positioned between the cover plate and the intake opening. This sound-absorbing element is, in particular, a sound-absorbing mat, which reduces the noise emission
Data Source
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AI summary
The invention relates to an electric blower with a blower coil (10) comprising a first axial end wall (20), a second axial end wall (22), and a blowing air outlet (11). An electric motor (30) is mounted on the first axial end wall (20) and drives a blower wheel (8) rotating within the blower coil (10). The blower wheel draws in ambient air through an intake opening (9) in the second axial end wall (22). A cover element (50) is arranged in front of the intake opening (9), the cover surface (52) of which is larger than the air inlet surface (42) of the intake opening (9). In order to draw in a large quantity of ambient air with low noise, the cover element (50) is designed as a cover disc (51), wherein an annular gap (54) is formed between the disc edge (53) and the blower spiral (10), which forms the inflow channel (80) for the direct access of ambient air.