Modular Hood Muffler With Active-Passive Noise Suppression
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Solution Overview
Problem
Existing fume extractor hoods suffer from high noise levels due to mechanical components and air flow turbulence, with previous solutions like active noise cancellation systems and muffler units being inefficient and not versatile enough for different hood types.
Innovation Solution
A modular muffler unit with a pentagonal cross-section, combining an active noise suppression system using loudspeakers and microphones with a control unit, and passive noise suppression using sound-absorbing materials, designed for easy installation on various hood types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If active noise cancellation systems are integrated into the hood, then noise suppression is improved, but the system complexity and lack of versatility worsen
Solution Approach 1:
The noise suppression system is divided into separate modular components: a muffler unit with active noise cancellation that can be independently installed and removed from the hood. This segmentation allows the noise suppression function to be added without complicating the overall hood system architecture, while maintaining versatility across different hood models.
Solution Approach 2:
The muffler unit acts as an intermediary component between the motor unit and the hood structure. It provides the active noise cancellation function as a separate module that interfaces with existing hood components without requiring integration into the hood's core structure, thus avoiding increased system complexity.
2Ease of manufacture
If conventional muffler designs with circular or square cross-sections are used, then manufacturing simplicity is improved, but noise suppression effectiveness worsens
Solution Approach 1:
The muffler unit employs a pentagonal cross-section instead of conventional circular or square shapes. This asymmetric geometry disrupts the propagation paths of turbulent air flow and noise waves, creating more effective noise suppression. The pentagonal shape with its five sides and angular transitions prevents the formation of coherent noise patterns that occur in symmetric geometries, thereby reducing noise transmission while remaining manufacturable.
3Adaptability or versatility
If the muffler unit is designed for easy installation, then adaptability to different hood types is improved, but structural integration may worsen
Solution Approach 1:
The muffler unit is designed as a universal module that can be installed on various types of hoods regardless of their specific configuration. It features standardized connection interfaces that accommodate different hood models, allowing the same muffler unit to serve multiple applications while maintaining stable structural integration through its fixed mounting system.
Solution Approach 2:
The muffler unit includes pre-configured fixed mounting elements and connection interfaces that are prepared in advance for installation. This preliminary preparation of mounting structures ensures that the unit can be quickly installed on different hood types without requiring custom structural modifications, thereby maintaining both versatility and structural stability.
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 muffler unit achieves significant noise cancellation, with up to 9.0 dBA reduction at the error microphone and a 3 dB improvement over square-section conduits, providing effective noise suppression without altering the hood's structure or aesthetics.
Implementation Method 1
passive noise suppression system comprising a sound-absorbing material arranged between said microphones
Implementation Method 2
active noise suppression system comprising at least one loudspeaker
Implementation Method 3
at least two microphones connected to a control unit
Data Source
Figure 1
Figure 1A
Figure 2~3
AI summary
A muffler unit (4) for fume extractor hood is disclosed, which comprises an active noise suppression system, comprising at least one loudspeaker (6), and at least two microphones (M1, M2) connected to a control unit (7), and a passive noise suppression system comprising sound-absorbent material (8) disposed between said microphones (M1, M2). The muffler module (4) comprises a conduit (40) with upper fixing means (41) and lower fixing means (42) designed to be removably fixed respectively to a motor unit (2) and to a conveyor plate (3) of a hood (1).