Composite Refractory Lance for Molten Metal LIBS Probing
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Solution Overview
Problem
Existing lances for real-time, continuous LIBS compositional measurement of molten materials at high temperatures suffer from low mechanical strength, thermal shock, corrosion, and chemical reactivity, with conventional materials like alumina, fused silica, and SiAlON II being insufficiently resistant to these conditions, and additional cooling mechanisms posing safety hazards.
Innovation Solution
A refractory lance assembly comprising a non-porous ceramic immersion tube and metal extension tube, encased by a shroud, which is resistant to high temperatures and thermal shock, and injectable with inert gas to mitigate fluid contamination, allowing for accurate optical probing of molten materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional materials like alumina, fused silica, and SiAlON are used for the lance, then the lance can withstand high temperatures, but the mechanical strength and resistance to thermal shock and corrosion are insufficient
Solution Approach 1:
The lance is constructed as a composite structure with a ceramic immersion tube (resisting thermal and chemical attack) coupled to a metal extension tube (providing mechanical strength). This composite approach allows each material to operate in its optimal performance range, resolving the contradiction between temperature resistance and mechanical strength.
Solution Approach 2:
The lance is divided into two distinct segments: an immersion tube for high-temperature exposure and an extension tube for mechanical support. This segmentation allows each part to be optimized for its specific function, with the immersion tube focusing on thermal/chemical resistance and the extension tube on mechanical strength.
2Reliability
If cooling mechanisms are added to protect the lance from thermal shock, then the lance durability improves, but safety hazards increase
Solution Approach 1:
Instead of adding cooling systems to manage thermal shock, the invention uses the thermal shock resistance of the ceramic material itself as the protective mechanism. The ceramic immersion tube is specifically selected for its ability to withstand rapid temperature changes without cracking, converting the harmful thermal shock into a non-issue through material selection.
3Reliability
If porous ceramics are used for the lance, then chemical reactivity is reduced, but fluid contamination through the lance increases
Solution Approach 1:
The immersion tube is made from non-porous ceramic material, which simultaneously provides chemical inertness and prevents fluid penetration. This eliminates the trade-off between chemical resistance and contamination, as the non-porous structure blocks both reactive species and fluid ingress.
4Productivity
If a lance is inserted into the melt for LIBS measurement, then real-time compositional measurement is enabled, but the lance is exposed to thermal shock and corrosion
Solution Approach 1:
The lance uses a composite construction where the ceramic immersion tube provides thermal and chemical resistance during melt insertion, while the metal extension tube provides mechanical strength. This allows the lance to be inserted into molten metal for real-time measurement without compromising structural integrity.
Solution Approach 2:
Different parts of the lance have different material properties optimized for their local environment: the immersion tube uses ceramic for thermal/chemical resistance where it contacts the melt, while the extension tube uses metal for mechanical strength where it provides structural support outside the melt.
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 refractory lance assembly provides stable, real-time compositional measurements of molten metals at temperatures up to 1500°C, maintaining structural integrity and reducing contamination, thus overcoming the limitations of conventional lances.
Implementation Method 1
the immersion tube is at least partially manufactured of a non-porous ceramic, which is substantially resistant to corrosion and thermal shock at temperatures of at least 1500° C.
Implementation Method 2
the immersion tube is at least partially manufactured of a non-porous ceramic, which is substantially resistant to corrosion and thermal shock at temperatures of at least 1500° C.
Implementation Method 3
The encasing volume is injectable with the inert gas to mitigate fluid contamination of the longitudinally extended composite tube and immersed melt surface via the coupling.
Implementation Method 4
LIBS involves repetitively emitting short, high energy laser pulses from a remote location towards a target spot of molten material to ablate or vaporise matter to form a plasma.
Implementation Method 5
The plasma emits electromagnetic radiation which is analyzed via a spectrometer, and, like other spectroscopic techniques, this analysis is correlated to elemental composition and/or concentrations through analysis of the spectral signature of the plasma.
Implementation Method 6
The plasma emits electromagnetic radiation which is analyzed via a spectrometer, and, like other spectroscopic techniques, this analysis is correlated to elemental composition and/or concentrations through analysis of the spectral signature of the plasma.
Data Source
AI summary
Described are various embodiments of a refractory lance assembly and a composite refractory lance. In one embodiment, a refractory lance assembly is provided that comprises: an immersion tube having an immersion tip immersible within a melt and an extension tube coupled at an opposed end thereof to form a longitudinally extended composite tube therewith defining an optical path therein, wherein said longitudinally extended composite tube is injectable, in use, with an inert gas to form and probe an immersed melt surface. The assembly further comprises a shroud longitudinally encasing the composite tube and injectable with inert gas to mitigate fluid contamination of the composite tube and immersed melt surface.