Non-Contact Metal Strand Measurement via Light Pattern Projection

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Solution Overview

Problem

Current systems for measuring the geometric dimensions and weight of metal strands in continuous casting systems, particularly for billets or blooms, are not sufficiently accurate, reliable, or economically feasible, leading to production inefficiencies and potential defects in metal products.

Innovation Solution

A non-contact measurement device that projects light patterns onto metal strands and uses a correlative optical measurement method to determine geometric dimensions and speed, allowing for simultaneous measurement of multiple strands with high accuracy and low investment costs, while minimizing disruption to the continuous casting process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If contactless measurement methods are used for metal strands, then measurement reliability is improved, but measurement precision deteriorates

Engineering Contradiction:
Improvemeasurement reliabilityVSAvoidmeasurement precision
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent transitions from point-based laser Doppler velocity measurements to plane-based optical imaging measurements. By projecting light patterns onto the metal strand surface and capturing reflected images with cameras, the system measures geometric dimensions (width, height, diagonal) across two-dimensional cross-sections rather than single-point velocity data, thereby improving both reliability and precision simultaneously

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The system changes the measurement parameters from velocity-based indirect length calculation to direct geometric dimension measurement. By measuring width, height, and diagonal dimensions of the strand cross-section and calculating volume directly, the system achieves more precise and reliable measurements without the accumulation of errors inherent in indirect calculation methods

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If complex measurement systems are implemented, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improvemeasurement precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses optical imaging to create two-dimensional image copies of the metal strand cross-section. By capturing reflected light patterns with cameras and processing these images computationally, the system obtains precise geometric measurements without requiring physical contact or complex mechanical measurement apparatus, thereby achieving high precision with relatively simple device complexity

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The system replaces complex mechanical measurement systems with optical imaging and computational processing. Instead of using mechanical probes or contact-based dimensional measurement devices, the patent employs light projection and image capture to measure strand geometry, significantly simplifying the device while maintaining or improving measurement precision

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

3Reliability

If measurement systems are added to continuous casting plants, then measurement reliability is improved, but productivity deteriorates

Engineering Contradiction:
Improvemeasurement reliabilityVSAvoidproductivity
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent implements continuous non-contact optical measurement throughout the strand casting process. The measurement system operates continuously as the metal strand moves through the casting process, capturing images at multiple positions along the strand length without interrupting the continuous casting operation, thereby maintaining both high reliability and productivity

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The system introduces optical fields (light patterns) as intermediaries between the measurement system and the metal strand. This allows measurement data to be obtained without physical interaction that would slow down the process, enabling reliable measurements to be taken while the strand continues to move through the casting line at normal speed, thus preserving productivity

Inventive Principle:
Principle #24Intermediary (Mediator)

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 precise recording of geometric dimensions and weight of metal strands with high accuracy and reliability, reducing production defects and costs, and allowing for early detection of deviations from desired casting geometry without affecting the continuous casting process.

Implementation Method 1

at least one projection device (4) for projecting a light pattern (3) onto the metal strand (6)

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

at least one sensor (2) for generating a temporal sequence of two-dimensional images

Methodology Applied
Scientific EffectOptical detection: Photoelectric Effect

Implementation Method 3

From the spatial arrangement of the projection device (4) and the sensor (2) relative to the outlet region (18) as well as from the surface area (7) with the light pattern projected onto it, the evaluation unit (8) determines subsequently the geometric dimensions of the metal strand (6) at a plurality of positions along the longitudinal direction (XS) as well as a speed (VS) of the metal strand (6) in the production direction (X) using a correlative optical measuring method

Methodology Applied
Scientific EffectCorrelative optical measurement: Photogrammetry

Data Source

PatentEP4000761B1Contactless measuring of metal strands in a continuous casting plant
Publication Date: 2024.07.24 PRIMETALS TECH AUSTRIA GMBH
  • EP4000761B1 patent drawingFigure 1
  • EP4000761B1 patent drawingFigure 2
  • EP4000761B1 patent drawingFigure 3

AI summary

The invention relates to a device (1) and a method for the non-contact measurement of one or more metal strands (6, 6', 6") moving through a discharge area (18) of a continuous casting plant (11), particularly in billet or ingot format. The device (1) comprises projection devices (4, 4') for projecting light patterns (3, 3', 3", 3'''), sensors (2, 2') for generating temporal sequences (20, 20', 20") of two-dimensional images, and an evaluation unit (8). The sensors (2, 2') detect surface areas (7, 7', 7", 7''') of the metal strands (6, 6', 6") with the projected light patterns (3, 3', 3", 3''') in the images and transmit the sequences (20, 20', 20") to the evaluation unit (8).The evaluation unit (8) determines the geometric dimensions and a speed (VS, VS', VS") of the metal strands (6, 6', 6") based on the light patterns (3, 3', 3", 3''') detected in the images, for example by means of a correlative optical measurement method.