Stabilized Glow Plasma Control for Accurate Gas Mixture Measurement
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Solution Overview
Problem
Existing glow discharge optical emission spectroscopy (GD-OES) systems face challenges in maintaining stable glow plasmas at atmospheric pressure due to high gas flow rates, high gas concentrations, high voltages, and the high costs and energy intensity of noble carrier gases, leading to plasma quenching and instability, which affects gas analysis accuracy and efficiency.
Innovation Solution
The method involves controlling plasma operating conditions through real-time monitoring and dynamic resonant feedback control of electric fields, adjusting parameters such as electrode geometry, excitation frequency, and impedance to maintain a stable glow discharge within a desired operating range, using a plasma cell with dielectric barriers to shield electrodes and employing inert gases like nitrogen to reduce costs and energy demand.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional DC or RF power sources are used to sustain glow discharge, then the plasma can be maintained, but the discharge becomes inherently unstable and difficult to control
Solution Approach 1:
The system employs a feedback control mechanism where optical emissions from the plasma are monitored and used to adjust the excitation voltage dynamically. This closed-loop feedback stabilizes the glow discharge by automatically compensating for fluctuations in plasma conditions, eliminating the need for complex external control systems while maintaining reliable operation.
Solution Approach 2:
The invention transitions from conventional DC or RF power sources to an alternating excitation voltage operating in a resonant condition. This parameter change in the excitation method fundamentally alters the plasma behavior, enabling stable glow discharge through the resonant interaction between the alternating voltage and plasma particles, thereby improving reliability without increasing device complexity.
2Reliability
If high power is used to sustain the plasma, then the discharge can be maintained, but the stability and control of the glow discharge deteriorates
Solution Approach 1:
The system uses periodic alternating excitation voltage instead of continuous high power input. By applying energy in periodic cycles that resonate with the plasma, the system maintains stable glow discharge with reduced overall energy consumption. The resonant condition ensures efficient energy transfer during each cycle, avoiding the waste associated with continuous high-power application.
Solution Approach 2:
The plasma itself provides feedback through its optical emissions, which are monitored to automatically adjust the excitation parameters. This self-regulating mechanism allows the system to maintain stable discharge at optimized power levels without requiring external intervention or excessive energy input, enabling the plasma to self-stabilize at efficient operating conditions.
3Stability of the object's composition
If dynamic control of electric field is implemented to stabilise glow plasma, then emission stability improves, but the system complexity increases
Solution Approach 1:
The system implements feedback control by monitoring optical emissions and using this information to dynamically adjust the alternating excitation voltage. This feedback loop stabilizes the glow discharge emissions by automatically compensating for variations in plasma conditions, achieving high emission stability through an integrated control mechanism that does not significantly increase overall system complexity.
Solution Approach 2:
The alternating excitation voltage serves multiple functions simultaneously: it provides the primary energy input to sustain the plasma, creates resonant conditions for stable discharge, and acts as the control parameter that is dynamically adjusted based on feedback. This multi-functionality reduces the need for separate control components, thereby stabilizing emissions without proportionally increasing system complexity.
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 approach enables stable glow plasmas under varying conditions, allowing for accurate and efficient gas analysis with enhanced signal-to-noise recovery, reducing the need for vacuum systems and minimizing greenhouse gas production.
Implementation Method 1
generating an electric field within a plasma cell using an alternating excitation voltage to excite particles within the cell, to produce a glow discharge from a plasma in the plasma cell in a resonant condition
Implementation Method 2
produce a glow discharge from a plasma in the plasma cell in a resonant condition
Implementation Method 3
monitoring, in each excitation cycle of the alternating excitation voltage, one or more signals that correlate with glow discharge optical emissions from the plasma in the plasma cell
Data Source
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AI summary
Provided are methods, apparatus and systems for stabilisation of a glow discharge from a plasma. Also provided are methods, apparatus and systems for processing optical signals from a stabilised glow plasma with enhanced signal to noise recovery. A first method comprises: generating an electric field within a plasma cell using an alternating excitation voltage to excite particles within the cell, to produce a glow discharge from a plasma in the plasma cell in a resonant condition; monitoring, in each excitation cycle of the alternating excitation voltage, one or more signals that correlate with glow discharge optical emissions from the plasma in the plasma cell; and, in response to said monitoring, controlling one or more operating conditions for the plasma cell to maintain the glow discharge emissions from the plasma within a desired operating range in each excitation cycle of the alternating excitation voltage. A relatively stable glow discharge optical emission is maintained via dynamic resonant feedback control of operating conditions such as the electric field that is used to excite particles within the plasma cell. The stabilisation of the glow plasma can be used in glow discharge optical emission spectroscopy (GD-OES) for gas analysis and in other applications.