Compact Molten Metal Probe for Fast Immersion Measurement

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Solution Overview

Problem

Existing measuring probes for molten metals are bulky, costly, and have long response times, leading to material contamination, high energy consumption, and unreliable measurements, especially in electric arc furnaces, where standard drop-in sensors cannot be used due to vessel design.

Innovation Solution

A compact, lightweight measuring probe with optimized wire diameter and carrier tube ratio, featuring individual wires and a metal body, allowing for accelerated immersion and reduced exposure time, enabling reliable measurements through available entry points without disturbing the metallurgical process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a heavy measuring head is used to pull the cable out and gain speed for immersion, then the probe can sink deep enough under the melt surface to obtain reliable measurement data, but the probe mass increases to 6-8 kg with high material costs

Engineering Contradiction:
Improvemeasurement reliabilityVSAvoidprobe mass
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The probe is divided into two separate components: a lightweight sensor unit that is dropped into the melt for measurement, and a separate carrier element that remains outside. This segmentation eliminates the need for a heavy measuring head, reducing probe mass while maintaining measurement reliability through the dedicated sensor design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sensor unit is extracted from the heavy carrier structure and dropped separately into the melt. Only the essential sensing components are immersed, while the supporting infrastructure remains outside, significantly reducing the mass that must be accelerated and immersed.

Inventive Principle:
Principle #2Taking out (Extraction)

2Duration of action of stationary object

If a thick cable with outer diameter 9-10 mm is used to withstand the molten metal environment for more than 10 s, then the cable can survive the required travel time and measurement duration, but the carrier tube dimensions and measuring head mass increase

Engineering Contradiction:
Improvecable withstand timeVSAvoidmeasuring head mass
Core Design Contradiction:
Duration of action of stationary objectVSWeight of moving object

Solution Approach 1:

The cable is extracted from the immersion path and kept outside the melt environment. The lightweight sensor unit is dropped without a heavy cable attached during immersion, eliminating the need for massive cable protection structures while the cable remains available for data transmission.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system is segmented so that the cable function is separated from the immersion function. The sensor unit operates independently during immersion, and the cable connects to it after or during the process, eliminating the need for the cable to be part of the heavy immersed structure.

Inventive Principle:
Principle #1Segmentation

3Speed

If the probe is dropped from a height of 10-20 m above the molten metal level, then the probe gains sufficient speed to sink deep under the melt surface, but the immersion point becomes unreliable and extra contaminating material is introduced

Engineering Contradiction:
Improveprobe immersion speedVSAvoidimmersion point controllability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The gravitational free-fall mechanism is replaced with an active acceleration system. The sensor unit is accelerated to the required speed through a controlled mechanism immediately before immersion, eliminating the long drop distance and providing precise control over the immersion point and speed.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The acceleration of the sensor unit is performed in advance through a controlled mechanism right before immersion. This preliminary acceleration achieves the necessary immersion speed without requiring a long drop, and the immersion point can be precisely controlled through the acceleration system's positioning capabilities.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4632375B1Measuring probe for molten metal
Publication Date: 2026.01.14 HERAEUS ELECTRO NITE INT NV
  • EP4632375B1 patent drawingFigure 1
  • EP4632375B1 patent drawingFigure 2~3
  • EP4632375B1 patent drawingFigure 4

AI summary

The present invention relates to a measuring probe for a molten metal, comprising a sensor unit adapted to determine at least one parameter of the molten metal, a signal line connected to the sensor und and a carrier element. The sensor unit comprises a sensing element and a metal body. The signal line comprises at least two wires and the inner diameter of the carrier tube is between 7 to 20 time the outer diameter of the wires. In a further aspect, the invention relates to a method to measure the at least one parameter of a metal melt.