Gas Sensor Vibrator with Segmented Piezoelectric Elements
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Solution Overview
Problem
Existing gas detection methods, such as those using Helmholtz resonance, face challenges in accurately measuring hydrogen gas concentrations due to diverging resonant frequencies between the gas and piezoelectric elements, leading to reduced sound pressure and detection difficulties, especially at high concentrations.
Innovation Solution
A gas sensor design incorporating a resonator with a vibrator featuring multiple vibrating bodies with differing frequency characteristics and a heater that outputs sound waves by resonance, allowing for enhanced detection of hydrogen gas across a wide concentration range by converting sound waves into electric signals for precise concentration calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single piezoelectric element is used to cause Helmholtz resonance in the gas container, then the device structure is simple, but the resonant frequency of the gas diverges from the piezoelectric element frequency at high hydrogen concentrations, reducing sound pressure and detection accuracy
Solution Approach 1:
The vibrator is divided into multiple piezoelectric elements (first and second piezoelectric elements) with different frequency characteristics. Each piezoelectric element operates at different frequency ranges, allowing the system to maintain resonance across a broader frequency spectrum and accurately detect hydrogen concentrations regardless of whether the resonant frequency shifts to high or low values.
Solution Approach 2:
The system changes the operating frequency parameters by selecting different piezoelectric elements based on the detection conditions. When hydrogen concentration is high, the system uses piezoelectric elements with lower resonant frequencies; when concentration is low, it uses elements with higher resonant frequencies, thereby adapting to the shifting resonant frequency of the gas and maintaining detection accuracy.
2Measurement precision
If the resonant frequency of the gas is much higher than the piezoelectric element frequency, then hydrogen concentration can be detected, but the sound pressure by Helmholtz resonance is reduced making it difficult to detect resonance
Solution Approach 1:
The system dynamically adjusts the driving frequency of the piezoelectric elements to match the resonant frequency of the gas. By continuously adapting the frequency of vibration to follow the gas resonant frequency, the system maintains strong resonance and sound pressure across all hydrogen concentration levels, making resonance always detectable.
Solution Approach 2:
The piezoelectric elements generate mechanical vibrations at frequencies that excite Helmholtz resonance in the gas container. By using multiple piezoelectric elements with different frequency characteristics, the system ensures that mechanical vibrations are always applied at the correct frequency to produce strong resonant sound pressure, overcoming the detection difficulty.
3Ease of manufacture
If a single frequency piezoelectric element is used, then the device is simple to manufacture, but it cannot effectively detect hydrogen across a wide concentration range
Solution Approach 1:
The vibrator is designed with multiple piezoelectric elements that can handle different frequency ranges, making the single device capable of detecting hydrogen across the entire concentration range from low to high levels. This multi-functional vibrator replaces the need for multiple separate detection devices, maintaining ease of manufacture while achieving broad adaptability.
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 increases the sensitivity and accuracy of hydrogen gas detection, enabling effective measurement across a broad concentration range, including both low and high concentrations, by utilizing a resonator with a vibrator that outputs sound waves across a wide frequency range, thereby improving detection capabilities.
Implementation Method 1
causing a gas inside a container provided with an opening to undergo Helmholtz resonance by being oscillated by one piezoelectric element disposed in the container
Implementation Method 2
oscillated by one piezoelectric element disposed in the container
Implementation Method 3
at least one converter that converts sound waves outputted from the at least one resonator to an electric signal
Implementation Method 4
a heater that heats a gas inside the at least one resonator, and that outputs sound waves by resonance of the at least one resonator
Data Source
AI summary
A gas sensor includes: at least one resonator; a vibrator provided on the at least one resonator; at least one converter that converts sound waves outputted from the at least one resonator to an electric signal; and a detection unit that detects a specific gas on the basis of the electric signal attained by conversion by the at least one converter, wherein the vibrator includes at least either one of: a plurality of vibrating bodies that have respectively differing frequency characteristics during vibration, that vibrate a gas inside the at least one resonator, and that output sound waves by resonance of the at least one resonator; and a heater that heats a gas inside the at least one resonator, and that outputs sound waves by resonance of the at least one resonator.