Photoacoustic Sensor Active Valve Gas Cell Sealing
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Solution Overview
Problem
Efficient and economic control of access to sample gases in photoacoustic sensors is challenging, affecting the accuracy and reliability of gas detection.
Innovation Solution
A photoacoustic sensor system incorporating a gas cell with an active valve, comprising a speaker with a permanent magnet, voice coil, and diaphragm, controlled by AC or DC signals to manage gas cell opening and sealing, ensuring precise sampling and detection periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a passive valve or manual control is used for gas cell access, then device complexity is reduced, but measurement precision and detection reliability deteriorate due to inability to maintain consistent sealing and sampling conditions
Solution Approach 1:
The patent replaces traditional mechanical valve control systems with an acoustic field-based control mechanism. By using acoustic waves to manipulate the gas cell access and sealing, the system eliminates complex mechanical moving parts while achieving precise control over gas sampling and detection phases, thereby improving measurement precision without proportionally increasing device complexity
Solution Approach 2:
The patent introduces an acoustic field as an intermediary between the control system and the gas cell access mechanism. This acoustic intermediary enables precise timing control of gas entry and sealing without requiring direct mechanical actuation, resolving the contradiction between measurement precision and device complexity by decoupling the control function from mechanical complexity
2Ease of operation
If the gas cell remains open continuously for sampling, then ease of operation is improved, but reliability deteriorates due to contamination and loss of sealed detection environment
Solution Approach 1:
The patent implements periodic opening and closing of the gas cell using acoustic control. The cell is opened periodically to allow gas sampling, then closed and sealed for the detection phase. This periodic action ensures the cell is open only when needed for sampling while maintaining a sealed environment during detection, thereby preserving both ease of operation and detection reliability
Solution Approach 2:
The patent performs preliminary gas sampling before sealing the gas cell for detection. By completing the sampling action beforehand and then sealing the cell, the system ensures that the detection environment is prepared and sealed in advance, preventing contamination during the detection phase while maintaining operational simplicity
3Reliability
If the gas cell is sealed during sampling, then reliability is improved by preventing contamination, but ease of operation worsens due to difficulty in introducing fresh sample gas
Solution Approach 1:
The patent uses acoustic field control to manage gas cell access, replacing complex mechanical sealing and opening mechanisms. The acoustic control allows the cell to be sealed during detection to maintain sample integrity while enabling easy introduction of fresh gas during sampling phases through acoustic actuation, resolving the contradiction between reliability and ease of operation
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 system effectively controls gas access, enhancing the signal-to-noise ratio and allowing for accurate analysis of gas properties and concentration by maintaining a sealed environment during detection, thereby improving the detection efficiency and reliability.
Implementation Method 1
The speaker may include a permanent magnet, a voice coil, and a diaphragm attached to the voice coil
Implementation Method 2
molecules of sample gases, when exposed to certain frequencies of radiant energy, to absorb the energy and reach higher levels of molecular vibration and rotation thereby to reach a higher temperature and pressure
Implementation Method 3
a detector to detect the sample gas within the gas cell to generate output electrical signals in response to acoustic signals generated by pressure fluctuations of the radiated sample gas caused by the radiation
Data Source
AI summary
Various embodiments of the application provide a photoacoustic sensor, which includes: a gas cell having an opening; a light source to generate a radiation to radiate sample gas within the gas cell; a detector to detect the sample gas within the gas cell, and to generate electrical signals in response to acoustic signals generated by pressure fluctuations of the radiated sample gas caused by the radiation; and an active valve having a speaker aligned with the opening of the gas cell. The speaker having a voice coil and a diaphragm attached to the voice coil. A control signal is applicable for the speaker to control access of the gas cell. During sampling, the control signal causes the voice coil of the speaker to repeatedly or constantly lift the diaphragm from contact with the opening of the gas cell to allow sample gas enter the gas cell. While during detecting, the spring force of the voice coil causes the diaphragm in tight contact with the opening of gas cell to seal the gas cell.