LIBS Analysis Chamber for Molten Metal Stirring
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Solution Overview
Problem
Existing methods for on-line analysis of molten metals, particularly highly oxidizable metals like silicon, face challenges in providing reliable and continuous monitoring due to surface oxidation and instability, limiting their effectiveness in maintaining representative surface composition for LIBS analysis.
Innovation Solution
A device with rotary mechanical stirring means and an analysis chamber is used to maintain a stationary surface for LIBS analysis, employing mechanical stirring blades and orifices to renew the surface and stabilize the molten metal's level, combined with inert gas blowing to prevent oxidation and enhance detection limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If surface analysis of molten metal is performed by LIBS technique, then rapid and direct analysis is achieved, but surface oxidation and nitriding lead to unrepresentative composition measurements
Solution Approach 1:
The patent applies preliminary action by continuously renewing the metal surface through mechanical stirring before analysis occurs. The stirring blades actively mix the molten metal and bring fresh, unoxidized material to the surface, ensuring the analyzed surface represents the bulk composition rather than being contaminated by surface reactions.
Solution Approach 2:
The patent implements an inert atmosphere by introducing noble gas (argon or nitrogen) through sparging devices that bubble through the molten metal. This creates a protective inert environment that prevents oxidation and nitriding of the metal surface, ensuring accurate composition measurements by LIBS technique.
2Measurement precision
If mechanical stirring is used to renew the surface, then representative composition is achieved, but surface stability and analysis reproducibility deteriorate
Solution Approach 1:
The patent applies periodic action by using controlled mechanical stirring at specific frequencies and durations. The stirring is performed in a rhythmic manner that continuously renews the surface to ensure representativeness, while the periodic nature allows the surface to stabilize between stirring cycles, maintaining reproducibility for LIBS analysis.
Solution Approach 2:
The patent implements continuity of useful action by maintaining constant or near-constant stirring during the analysis period. This continuous stirring ensures the surface remains representative of the bulk composition throughout the measurement process, while the controlled parameters maintain sufficient stability for reproducible analysis.
3Measurement precision
If inert gas sparging is used to prevent oxidation, then surface composition accuracy is improved, but surface instability increases due to bubble dynamics
Solution Approach 1:
The patent applies partial action by using moderate inert gas flow rates that are sufficient to prevent oxidation and maintain surface representativeness, but not so excessive as to create severe surface instability. The gas sparging is performed at optimized levels that balance protection from oxidation with maintenance of surface stability for analysis.
Solution Approach 2:
The patent implements parameter changes by optimizing the inert gas flow rate, bubble size, and sparging location to achieve the desired balance. By adjusting these parameters, the system prevents surface oxidation while minimizing surface disturbance, ensuring both accuracy and stability for LIBS analysis.
4Object-affected harmful factors
If remote analysis is performed to avoid heat damage, then device protection is achieved, but surface oxidation and nitriding occur
Solution Approach 1:
The patent implements inert atmosphere protection by introducing noble gas that forms a protective envelope over the molten metal surface. This inert environment prevents oxidation and nitriding reactions while allowing remote LIBS analysis to proceed without heat damage to the analytical equipment.
Solution Approach 2:
The patent uses the inert gas as an intermediary substance that sits between the molten metal and the atmosphere. This intermediary layer prevents harmful reactions by displacing oxygen and nitrogen, while allowing the laser analysis to penetrate through the gas to the metal surface without heat damage to the equipment.
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 solution enables continuous, reliable on-line monitoring of impurity concentrations in molten metals, ensuring accurate and stable surface analysis without the formation of invalidating slag or oxides, improving the detection limits and reducing analysis time and costs.
Implementation Method 1
the laser ablation of a material to create a plasma, then spectroscopic technology for the observation and analysis of the light spectrum of the plasma
Implementation Method 2
At the end of the laser pulse, the atomic and ionic species of the micro-plasma de-excite and then re-emit radiation that an analyzer, i.e. a spectrometer, captures
Data Source
AI summary
The main subject of the invention is a device (1), for analysing at least one oxidisable molten metal (2) using a LIBS technique, comprising LIBS analysing means (3), characterised in that it furthermore comprises mechanical rotary means (4, 5) for stirring a liquid bath of said at least one oxidisable molten metal (2), the mechanical stirring means (4, 5) comprising a central section (4), intended to be positioned above the liquid bath of said at least one oxidisable molten metal (2), containing an internal cavity (6) forming an analysis chamber, the central section (4) comprising a first end (4a) connected to the LIBS analysing means (3), and a plurality of mechanical stirring paddles (5) that are intended to be partially submerged in the liquid bath of said at least one oxidisable molten metal (2) and that are connected to a second end (4b) of the central section (4) opposite the first end (4a) of the central section (4), the LIBS analysing means (3) being configured to allow the surface (S) of said at least one oxidisable molten metal (2) located in the portion plumb with the internal cavity (6) of the central portion (4) to be analysed.