Side-View CCD Imaging for Electric-Resistance-Welded Pipe Molten State Monitoring

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Solution Overview

Problem

Existing methods for monitoring the state of electric-resistance-welded pipe production, such as those using cameras and fiber scopes, face challenges in accurately capturing the molten state and butting state due to issues like inverted V-shape welds and insufficient image resolution, leading to difficulties in controlling heat input and detecting defects like scale inclusion.

Innovation Solution

A system that uses relay lenses and an insulated container with a CCD camera and data processing system to capture high-definition images of the welded parts, analyze the molten state and butting state, and display results for improved control and defect detection, allowing for real-time monitoring and adjustment of welding parameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a camera is placed directly above the weld point to take still images, then the imaging system is simple to implement, but the butting state (inverted V-shape) cannot be distinguished from suitable states, making heat input state monitoring inaccurate

Engineering Contradiction:
Improveimaging system implementationVSAvoidheat input state monitoring accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent transitions from top-down imaging (single dimension) to side-view imaging (different dimension), allowing the imaging means to capture the butting state and molten pool shape from a lateral perspective, thereby distinguishing inverted V-shape welds from suitable weld configurations

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

2Ease of operation

If a fiber scope is used to obtain images of welded parts, then the imaging device can be positioned inside the pipe, but the image resolution is insufficient and images between fibers show clearance, creating a mesh state that obscures weld face details

Engineering Contradiction:
Improveimaging device positioningVSAvoidweld face state analysis accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent extracts the imaging means from the constrained fiber scope configuration and positions it externally at the side of the welded parts, eliminating the mesh artifact problem while maintaining internal observation capability through strategic positioning of the imaging device

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the fiber optic mechanical system with a direct digital imaging system (CCD camera) that captures high-resolution images of the welded parts from the side, providing superior image quality for analyzing molten state and butting configuration

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

3Measurement precision

If relay lenses are used to relay images from welded parts, then high-definition images can be obtained, but the container must be made of insulated material to prevent noise interference, increasing device complexity

Engineering Contradiction:
Improveimage definition qualityVSAvoidcontainer material requirements
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces a container made of heat-insulating material as an intermediary between the high-temperature welded parts and the imaging system, blocking thermal noise and electromagnetic interference while allowing optical signals to pass through, thus protecting the sensitive imaging and relay lens components

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

This system enables high-precision analysis and display of welding states, enhancing response control, productivity, and operator efficiency while reducing noise interference and improving the accuracy of defect detection in electric-resistance-welded pipe production.

Implementation Method 1

relay an image based on light emitted from the welded parts

Methodology Applied
Scientific EffectLight emission: Luminescence

Implementation Method 2

container containing said relay lenses and made at least in part by an insulated material

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP2221137B1Welded state monitoring device and method
Publication Date: 2020.01.22 NIPPON STEEL CORPORATION
  • EP2221137B1 patent drawingFigure 1(a)~1(b)
  • EP2221137B1 patent drawingFigure 2(a)~2(b)
  • EP2221137B1 patent drawingFigure 3

AI summary

A system and method for monitoring the molten state for enabling a molten state, butting state, or other state of electric-resistance-welded pipe on-line more accurately than in the past are provided. That is, a mirror 23 provided at a front end side inside a container 21 receives light emitted by the welded parts 5 of the tube-shaped steel strip 1 themselves through heat resistant glass 22 from the side direction and reflects the image of the welded parts 5 of the tube-shaped steel strip 1 in the direction of a relay lens 24 provided at a base end side of a relay lens unit 13. The relay lenses 24 relay the image of the welded parts 5 of the tube-shaped steel strip 1 to a conversion lens 12, then the conversion lens 12 forms that image on the imaging area of a CCD camera 11. Therefore, it is possible to capture the welded parts 5 of the tube-shaped steel strip 1 from the side direction by a resolution in accordance with the resolution of the CCD camera 11 and possible to obtain information of the welded parts 5 of the tube-shaped steel strip 1 more accurately than in the past and on-line.