Contactless Optical Inspection for Plastic Butt Welds

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Solution Overview

Problem

Existing manual visual assessment of butt welds in plastic pipes is time-consuming and inconsistent due to the human factor, while existing non-contact methods like ultrasonic testing are also labor-intensive and require cooling, hindering efficient pipeline installation.

Innovation Solution

A device comprising a support structure, lighting system, and a movable sensor, such as a digital camera, that inspects the weld seam and pipe ends contactlessly, allowing continuous recording and comparison against standards during the cooling process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If manual visual assessment is used to inspect butt welds, then inspection can be performed, but it is time-consuming and expensive

Engineering Contradiction:
Improveinspection qualityVSAvoidinspection time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces manual visual inspection with an automated optical measurement system that uses a sensor, lighting device, and evaluation unit to automatically capture and assess weld seam images, eliminating the need for manual intervention while maintaining inspection quality

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

Solution Approach 2:

The system performs self-assessment by automatically capturing images of the weld seam, evaluating them against predetermined criteria, and generating inspection results without requiring human specialists, thereby reducing both time and cost

Inventive Principle:
Principle #25Self-service

2Reliability

If ultrasonic sensor inspection is used to inspect weld seams, then internal fusion can be detected, but the process is very time-consuming and requires cooling

Engineering Contradiction:
Improveweld inspection accuracyVSAvoidinspection speed
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent replaces ultrasonic sensing with optical sensing that captures images of the weld seam surface, enabling rapid inspection without the cooling requirements and time constraints of ultrasonic methods while maintaining sufficient inspection accuracy for surface defects

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

Solution Approach 2:

The inspection system operates during the cooling process itself rather than requiring the weld to be completely cooled first, by capturing images at appropriate stages of the cooling process, thereby eliminating the waiting time required by ultrasonic methods

Inventive Principle:
Principle #10Preliminary action

3Reliability

If automated sensor inspection is implemented, then inspection consistency is improved, but device complexity increases

Engineering Contradiction:
Improveinspection consistencyVSAvoidinspection system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system uses a digital camera that can capture images under different lighting conditions and from different angles, allowing a single device to perform multiple inspection functions and reduce overall system complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The evaluation unit serves as an intermediary that processes images from the sensor and compares them against predetermined evaluation criteria, simplifying the complexity by centralizing the evaluation logic in a dedicated component rather than distributing it across multiple systems

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 rapid, consistent, and cost-effective quality inspection of butt welds without additional time expenditure, ensuring compliance with standards and detecting defects or contaminants.

Implementation Method 1

a lighting device (6), in particular as backlight, for illuminating the weld seam (9) or the pipe ends (5)

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

an electronic light-sensitive sensor (4), in particular a digital camera, for contactlessly inspecting and recording the weld seam (9) or pipe ends (5)

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentEP2963380B2Contactless inspection for butt welding
Publication Date: 2025.06.25 GEORG FISCHER ROHRLEITUNGSSYSTEME AG
  • EP2963380B2 patent drawingFigure 1
  • EP2963380B2 patent drawingFigure 2~3
  • EP2963380B2 patent drawingFigure 4~5

AI summary

Device and an associated method for non-contact inspection of a butt weld of plastic pipes and fittings comprising a support device, a light source and at least one sensor for checking the pipe ends or fitting ends to be welded and the weld seam, wherein the sensor is an electronic light-sensitive sensor, preferably a digital camera, and this serves for inspection.