Induction Coil Priming for Ceramic Metal Filters
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Solution Overview
Problem
Ceramic foam filters used for purifying liquid metal face challenges in priming, leading to incomplete filling, higher liquid velocities, lower throughput, and reduced inclusion collection efficiency due to poor wetting characteristics and air entrapment, especially in filters with higher pore density and smaller window sizes.
Innovation Solution
A method utilizing a low frequency induction coil to generate a magnetic field that induces Lorentz forces, allowing for complete priming of ceramic foam filters without vacuum or gas pressure, enabling efficient priming of thicker filters and those with small window sizes, and allowing for filter media reuse by maintaining them hot between casting cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ceramic foam filter with higher pore density and smaller window size is used to improve filtration efficiency, then inclusion collection efficiency is improved, but priming difficulty increases and air entrapment worsens
Solution Approach 1:
The filter media is preheated to a temperature sufficient to melt frozen metal in the pores before reuse, and an induction coil is used to generate a magnetic field that induces Lorentz forces to force liquid metal into the filter pores during priming. These preliminary actions address the priming difficulty before filtration begins
Solution Approach 2:
The patent changes the temperature parameter of the filter media by heating it to improve wetting characteristics and reduce air entrapment. The induction coil introduces a magnetic field parameter that creates Lorentz forces to enhance metal penetration into the filter pores, making priming easier for high pore density filters
2Reliability
If metallostatic head is increased to improve priming efficiency, then complete filling of filter is achieved, but operational pressure drop increases
Solution Approach 1:
The patent replaces the purely mechanical metallostatic head pressure system with an electromagnetic system. An induction coil generates a magnetic field that induces Lorentz forces in the liquid metal, providing an alternative mechanism to force metal into the filter pores without relying solely on high gravitational head, thus reducing operational pressure drop while maintaining priming completeness
3Productivity
If filter media is preheated to improve flow and priming efficiency, then metal flow into filter is enhanced, but localized overheating can occur causing thermal damage
Solution Approach 1:
The patent substitutes thermal preheating with electromagnetic induction using an induction coil. The coil generates a magnetic field that induces eddy currents in the liquid metal, creating Lorentz forces that enhance metal flow and priming efficiency without requiring high temperatures that could cause thermal damage to the filter media or localized overheating
4Reliability
If vacuum system is used to improve priming of thick filters, then priming efficiency is improved, but device complexity increases
Solution Approach 1:
The patent replaces the vacuum system with an induction coil that generates a magnetic field. The induced Lorentz forces in the liquid metal provide the driving force for priming thick filters with small window sizes, achieving effective priming without the complexity of vacuum equipment while maintaining reliability
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 ensures complete priming with lower metallostatic heads, improves filtration efficiency, and allows for the reuse of filter media, reducing operational pressures and increasing the effectiveness of inclusion removal in liquid metal processing.
Implementation Method 1
A method utilizing a low frequency induction coil to generate a magnetic field that induces Lorentz forces, allowing for complete priming of ceramic foam filters
Implementation Method 2
an induction coil surrounding the filter element, wherein said induction coil is accommodated in a separator separating the induction coil from the liquid metal flow and configured to produce a magnetic field
Implementation Method 3
the media could be caused to self-heat due to the resistive (I 2R) heating of the current flow through the media
Data Source
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AI summary
An apparatus and method are described for effectively priming a non-electrically conductive filter for removal of solid inclusions from liquid metal. In one embodiment, the ceramic filter media is surrounded by a low frequency induction coil (1 -60 Hz) with its axis aligned in the direction of the net metal flow. The coil is positioned to enhance the heating of any metal frozen onto, or in the pores of, the filter element. In one embodiment, the coil is positioned in order to generate Lorentz forces, which act to cause heated metal to impinge on the upper surface of the filter element, enhancing the priming action. Once a filter equipped with such a coil has been primed, it can be kept hot or reheated, and subsequently reused during several batch tapping sequences.