Gas Detection Unit With Partition-Based Acoustic Isolation
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Solution Overview
Problem
Gas sensors in apparatuses with sound-emitting components, such as smart home devices, suffer from reduced detection accuracy due to resonance and vibration-induced noise, particularly affecting microstructure-based detectors.
Innovation Solution
The apparatus design includes a gas measurement unit demarcated by a partition with a hole, where the resonance frequency is set outside the frequency band of unwanted sound, using specific formulas to determine the hole's effective length and cross-sectional area, and positioning the vibration source and detector at nodal positions to minimize vibration transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the gas sensor is placed in the same housing as sound-emitting components, then the device can be miniaturized and integrated, but the detection accuracy degrades due to vibration-induced noise and resonance
Solution Approach 1:
The housing is divided into a sound-emitting section and a gas detection section by a partition wall. The partition includes a hole with specific acoustic impedance characteristics that allows gas molecules to pass through while blocking sound waves and vibrations, thus separating the gas sensor from vibration sources while maintaining device integration
Solution Approach 2:
The partition with the hole acts as an intermediary structure between the sound-emitting section and gas detection section. It selectively transmits gas molecules while blocking sound and vibration, enabling co-location of components without compromising detection accuracy
2Device complexity
If the resonance frequency of the gas detection space is set low, then the device structure can be simplified, but the detection accuracy decreases due to resonance with low-frequency sound from speakers and motors
Solution Approach 1:
The acoustic impedance of the partition is optimized by controlling the hole's cross-sectional area and length. This parameter optimization allows the partition to block low-frequency sound waves while maintaining gas permeability, enabling the gas detection space to have low structural complexity without resonating with motor and speaker frequencies
Solution Approach 2:
The hole in the partition has a curved surface design with specific radius of curvature. This curvature optimizes the acoustic impedance characteristics, enhancing the partition's ability to block sound while allowing gas passage, thus preventing resonance without complicating the structure
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 design significantly enhances the detection accuracy of gas sensors by reducing the impact of vibration-induced noise, allowing for precise gas concentration measurement.
Implementation Method 1
the partition includes a hole with a cross-sectional area S and a length L, and an acoustic impedance Z of the hole is 4000 kg/m2s or more
Implementation Method 2
a light source that emits light in a wavelength range of 3.0 μm to 5.0 μm; a detector that detects the light
Data Source
AI summary
Provided is an apparatus with a gas detection function capable of detecting a detection target gas with high accuracy. An apparatus with a gas detection function comprises: a housing (10); a vibration source (20); and a gas measurement unit (40) located inside the housing and demarcated by a partition, wherein the vibration source is located outside the gas measurement unit, the gas measurement unit includes a detector (41) located on a substrate (30), and a gas detection space (42) provided with a hole (43) through which a gas passes, and a frequency f expressed by the following Formula (1):f=c2πSVLFormula (1)is 500 Hz or more, where V is a volume of the gas detection space, S is a cross-sectional area of the hole, L is an effective length of the hole, and c is a sound speed.