Drop-in Probe with Dense Counterweight for Slag Penetration
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Solution Overview
Problem
Existing drop-in sensors for molten metal temperature and carbon content measurement in steelmaking processes face challenges such as limited access, high capital costs, and difficulties in penetrating the slag layer and obtaining accurate measurements during the 'in-blow' phase due to buoyancy issues and signal cable degradation.
Innovation Solution
A drop-in probe with a measurement head featuring a reverse-filling solidification chamber and a thermocouple system, designed to rapidly fill and achieve in-situ density upon immersion, ensuring prolonged submersion and accurate temperature and carbon content measurements by minimizing buoyant forces and maintaining signal cable integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional drop-in sensors are used, then capital investment is reduced, but the sensors float on slag and fail to penetrate into molten metal
Solution Approach 1:
A dense material (such as tungsten, depleted uranium, or tungsten carbide) is attached to the forward end of the sensor probe to increase its bulk density. This counterweight ensures the probe sinks through the slag layer and becomes immersed in the molten metal, overcoming the buoyancy force that would otherwise cause the sensor to float on the slag surface.
Solution Approach 2:
The sensor probe is designed with non-uniform density distribution: the forward end contains dense material for sinking, while the rear portion contains the measurement components. This local quality differentiation allows the probe to penetrate slag effectively while maintaining functional integrity for temperature and carbon content measurements.
2Speed
If the probe is dropped from height to penetrate slag, then penetration capability is improved, but signal cable degradation occurs
Solution Approach 1:
The signal cable is pre-protected with a flexible protective coating or sheath that can absorb impact forces during the dropping process. This beforehand cushioning prevents cable degradation when the probe penetrates the slag layer at high speed, ensuring the cable remains functional throughout the measurement process.
3Measurement precision
If thermocouple is positioned for optimal contact, then measurement accuracy is improved, but random drop orientation causes errors
Solution Approach 1:
The sensor probe is designed with asymmetric geometry where the thermocouple junction is positioned at a specific location relative to the dense material and the opening. This asymmetric configuration ensures that regardless of the random drop orientation, the thermocouple will always achieve optimal contact with the molten metal, eliminating orientation-dependent measurement errors.
Solution Approach 2:
Instead of trying to control the drop orientation to achieve proper thermocouple contact, the design inverts the approach: the thermocouple is positioned such that it automatically achieves optimal contact regardless of orientation. The measurement function is made independent of the dropping direction by strategic component placement.
4Duration of action of stationary object
If solidification chamber has restrictions at fill opening, then thermal control is improved, but filling time increases
Solution Approach 1:
The fill opening geometry is dynamically optimized: the opening dimensions and shape are specifically designed to allow rapid filling of the solidification chamber while maintaining adequate thermal control. The opening is sized and shaped to balance the competing requirements of fast metal ingress and sufficient thermal isolation for accurate solidification temperature measurement.
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
Enables accurate and cost-efficient 'in-blow' measurements by ensuring the probe remains submerged long enough to obtain liquidus temperatures and carbon content data quickly, while protecting the signal cable from damage, thus improving the reliability and efficiency of steelmaking process monitoring.
Implementation Method 1
a first thermocouple having a first thermocouple junction enclosed within a wall which has a uniform internal geometry
Implementation Method 2
bath thermocouple
Implementation Method 3
The buoyant force acting on the body immersed in the molten steel will act in an upward direction, thereby resulting in a floating position partially or totally above the liquid steel
Implementation Method 4
reverse-filling uniform geometry solidification chamber
Data Source
AI summary
A drop-in probe for determining phase changes by thermal analysis of a sample of a molten metal includes a measurement head having a first end which is an immersion end and an opposing second end having an end face. A sample chamber is arranged within the measurement head. An opening, which is free of any restrictions and which is in communication with the sample chamber, is formed in the end face of the second end of the measurement head. The sample chamber includes a first thermocouple having a first thermocouple junction enclosed within a wall which has a uniform internal geometry. A ratio D/H of an internal diameter D of the sample chamber to a length H extending between the opening and the first thermocouple junction is between 0.1 and 1.2.