Measuring Probe Quartz Inlet Channel Gas Bubble Elimination

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Solution Overview

Problem

Existing measuring probes for molten metal sampling face challenges in preventing gas bubble formation, especially during oxygen blowing processes in converters, which complicates sampling and affects sample quality due to varying metal density and inert gas injection, and require improved methods for efficient temperature and composition monitoring.

Innovation Solution

A measuring probe design featuring a quartz glass inlet channel with a specific length-to-diameter ratio (L/D² < 0.6 mm⁻¹) and a sample chamber surrounded by a foundry sand body, allowing for gas-bubble-free sampling, along with a vented design and electrochemical sensors for versatile parameter measurement, and a back pressure less than 20 mbar to enhance sampling efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a measuring probe is used for sampling molten metal during oxygen blowing, then temperature and composition monitoring is enabled, but gas bubble formation occurs in the sample due to varying metal density and inert gas injection

Engineering Contradiction:
Improvesampling accuracyVSAvoidgas bubble formation
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by optimizing the geometric parameters of the inlet channel, specifically the length-to-diameter ratio (L/D), to control fluid dynamics and eliminate gas bubble formation. By setting L/D ≥ 10, the channel design changes the flow parameters to ensure complete filling of the sample chamber without gas entrapment, thus resolving the contradiction between sampling accuracy and gas bubble formation

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The inlet channel acts as an intermediary element between the molten metal source and the sample chamber. This intermediate structure with specific geometric properties (L/D ≥ 10) mediates the flow of molten metal, allowing it to fill the sample chamber completely while preventing gas bubbles from entering, thus protecting sample quality

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the sample chamber is completely filled at low temperatures, then gas-free sampling is achieved, but the process becomes complex due to varying metal density and inert gas injection

Engineering Contradiction:
Improvesample qualityVSAvoidsampling process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent simplifies the sampling process by changing the geometric parameter of the inlet channel (L/D ratio ≥ 10), which inherently controls the filling behavior. This parameter optimization ensures that the sample chamber fills completely from the bottom up, automatically preventing gas bubble entrapment without requiring complex control mechanisms or procedures

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The inlet channel design enables self-service functionality where the geometric structure itself (L/D ≥ 10) automatically ensures gas-free sampling. The channel's dimensions cause the molten metal to fill the chamber in a controlled manner that inherently excludes gas bubbles, eliminating the need for external intervention or complex operational procedures

Inventive Principle:
Principle #25Self-service

3Reliability

If a quartz glass inlet channel with specific L/D ratio is used, then gas-bubble-free sampling is achieved, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvegas-free samplingVSAvoidinlet channel dimensional precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent specifies a minimum threshold for the L/D ratio (≥ 10) rather than requiring precise control of absolute dimensions. This approach allows manufacturers to achieve the required performance with reasonable tolerances, as long as the ratio condition is met, thus balancing reliability with manufacturing feasibility

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by specifying the L/D ratio condition specifically for the inlet channel region, while other parts of the measuring probe can have standard manufacturing tolerances. This localized requirement focuses precision efforts where they are most critical (the inlet channel geometry) without unnecessarily increasing precision requirements throughout the entire device

Inventive Principle:
Principle #3Local quality

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 solution enables high-quality, gas-free sampling with simplified removal of samples, improving the accuracy and efficiency of molten metal analysis in both converters and electric arc furnaces by minimizing bubble formation and ensuring reliable data collection during the blowing process.

Implementation Method 1

the length L of a region of the quartz glass tube that runs in the measuring head has a ratio to the square of a minimum diameter D, which the quartz glass tube has at least one point in it, having an inner region of L/D² < 0.6 mm⁻¹

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

a sample chamber surrounded by a foundry sand body

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 3

A measuring probe design featuring a quartz glass inlet channel with a specific length-to-diameter ratio (L/D² < 0.6 mm⁻¹) and a sample chamber surrounded by a foundry sand body, allowing for gas-bubble-free sampling, along with a vented design

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Implementation Method 4

electrochemical sensors for versatile parameter measurement

Methodology Applied
Scientific EffectElectrochemical reaction: Electrochemiluminescence

Data Source

PatentEP2397834B1Measuring probes for measuring and sampling with a metal melt
Publication Date: 2019.01.23 HERAEUS ELECTRO NITE INT NV
  • EP2397834B1 patent drawingFigure 1
  • EP2397834B1 patent drawingFigure 2
  • EP2397834B1 patent drawingFigure 3

AI summary

The measuring probe comprises a measuring head (9) made of ceramic, cement or steel, which is mounted on a lance. The measuring head supports a temperature sensor and a sample chamber. The sample chamber is partially surrounded by the measuring head, and has an inlet channel extending through the measuring head. The inlet channel is made of a silica glass pipe, and has an inner area extending in the measuring head.