Debris Blower Resonator Structure for High-Frequency Noise Attenuation
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Solution Overview
Problem
Debris blowers, including electric and internal combustion engine (ICE) models, generate significant noise, particularly at higher frequencies, which is objectionable and can lead to hearing loss without proper ear protection.
Innovation Solution
Incorporation of a resonant chamber with first and second sections of varying volumes forming an acoustic resonator to attenuate noise, combined with sound deadening coatings and insulators, to reduce noise emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a resonant chamber with acoustic resonator is added to attenuate noise, then noise attenuation is improved, but device complexity increases
Solution Approach 1:
The resonant chamber is integrated within the existing motor enclosure structure, with the acoustic resonator formed by partitioning the chamber into first and second sections. This nesting approach allows noise attenuation functionality to be incorporated without significantly increasing overall device complexity, as the resonator utilizes the existing spatial framework of the motor enclosure.
Solution Approach 2:
The resonant chamber is divided into first and second sections with different volumes to create the acoustic resonator. This segmentation allows the system to target specific frequency ranges for noise attenuation while maintaining a relatively simple overall structure. The partitioning into distinct sections enables optimized acoustic performance without requiring complex multi-component assemblies.
2Object-affected harmful factors
If the resonant chamber is divided into first and second sections with different volumes, then noise attenuation performance is improved, but manufacturing complexity increases
Solution Approach 1:
The first and second sections of the resonant chamber are designed with different volumes to create specific acoustic resonance characteristics. By varying the local volume in different sections of the same chamber, the system achieves optimized noise attenuation performance. This local quality differentiation can be implemented through simple geometric variations or partitions that are relatively straightforward to manufacture, such as internal dividers or differently sized cavity sections.
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 acoustic resonator effectively attenuates noise above 1 kHz, providing up to 18 dBA reduction, making the blower more desirable and safer for operators.
Implementation Method 1
The resonant chamber has first and second sections encompassing corresponding first and second volumes of different sizes. The different sizes are selected to form an acoustic resonator. The acoustic resonator attenuates noise from the blower over a selected attenuation frequency range.
Implementation Method 2
The acoustic resonator attenuates noise from the blower over a selected attenuation frequency range
Data Source
AI summary
A blower apparatus includes a fan and motor generating an airflow from an inlet end to an outlet end of the debris blower. The airflow defines an airflow axis and a cross-sectional plane normal to the airflow axis. An enclosure provides an airflow path towards the outlet end. A resonant chamber is proximate an airflow entrance end of the enclosure. The resonant chamber has first and second sections encompassing corresponding first and second volumes of different sizes. The different sizes are selected to form an acoustic resonator. The acoustic resonator attenuates noise from the blower over a selected attenuation frequency range.