Active Muffler Duct for Server Chassis Noise Reduction
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Solution Overview
Problem
Existing noise reduction methods for blade chassis, particularly those using passive control measures, are inefficient and costly for low-frequency noise attenuation, as they require substantial materials and are ineffective in reducing noise from cooling fans which exceed safety standards.
Innovation Solution
An active muffler system combining passive noise reduction materials with an active noise control (ANC) system, featuring a duct with a blower and both passive and active noise reduction components, including microphones and speakers, to shift noise frequencies for absorption by passive materials, effectively reducing noise levels below and above 1000 Hz.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If passive noise control measures (absorptive materials, partitions, enclosures, barriers, silencers) are used to reduce low-frequency noise, then noise attenuation is achieved, but the solution becomes bulky, expensive, and ineffective
Solution Approach 1:
The patent replaces passive mechanical noise control systems (absorptive materials, partitions, enclosures, barriers, silencers) with an active noise control system that uses electronic signals. The system employs microphones to detect low-frequency noise, a DSP (digital signal processor) to generate anti-noise signals, and speakers to emit these signals, thereby eliminating the need for bulky passive control components while achieving effective low-frequency noise attenuation
Solution Approach 2:
The patent changes the approach from passive physical barriers to active electronic control by modifying the noise control parameter from physical structure to signal processing. The system dynamically adjusts the anti-noise signals based on real-time noise detection, enabling effective control of low-frequency noise without requiring the bulkiness associated with traditional passive measures
2Object-affected harmful factors
If passive noise control materials are used to reduce noise from cooling fans, then some noise reduction is achieved, but the materials required are substantial and the cost is high
Solution Approach 1:
The patent substitutes substantial quantities of passive noise control materials with an active noise control system consisting of microphones, DSP, and speakers. This electronic system targets the specific noise frequencies from cooling fans, providing effective noise reduction without requiring large volumes of absorptive materials or other passive control substances
3Object-affected harmful factors
If traditional passive control measures are used to attenuate low-frequency noise, then noise reduction is achieved, but the effectiveness is poor and the cost is high
Solution Approach 1:
The patent replaces expensive passive control measures with a more cost-effective active noise control system. The electronic system uses standard components (microphones, DSP, speakers) that are less expensive than substantial quantities of passive control materials, while providing superior effectiveness in attenuating low-frequency noise through electronic signal processing
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 active muffler system achieves up to 10 dBA reduction in separated tones and 5 dBA in frequency noise, providing a more efficient and cost-effective solution for noise reduction in blade chassis compared to traditional passive methods.
Implementation Method 1
Active Noise Control (ANC), on the other hand, can be very efficient and relatively cheaper in reducing low-frequency noise. Active Noise Control (ANC) is a technology using noise to reduce noise. It is based on the principle of superposition of sound waves. Generally, sound is a wave is travelling in space. If another, second sound wave having the same amplitude but opposite phase to the first sound wave can be created, the first wave can be totally cancelled.
Implementation Method 2
Passive noise control technology, which usually involves using absorptive materials or noise partitions, enclosures, barriers and silencers
Data Source
AI summary
An Active Muffler in the form of a duct having two open ends for conveying air from a within a cabinet to outside the cabinet. A fan or blower is incorporated in the duct. An Automatic Noise Control (ANC) unit is associated with the duct, and at least one microphone and at least one speaker are incorporated in to the duct for noise-reduction. An outer portion of the duct may be sound-absorbing material. the ANC unit may cause noise to be shifted to a frequency that can be absorbed by the sound-absorbing material.