Optical Thread Measurement for Small Diameter Pipes
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Solution Overview
Problem
Existing optical measurement techniques for internal threads, particularly in oil field pipes with small inner diameters, face challenges such as complex tactile centering, large installation space requirements, and difficulty in scanning conical threads efficiently, leading to long measurement times and reduced accuracy.
Innovation Solution
A compact optical measurement system comprising a confocal sensor and a galvo scanner, adjustable in multiple axes, is used to scan internal threads. This system includes a mirror that can be adjusted in two axes, allowing for efficient scanning of internal threads with a small inner diameter, and enables two-dimensional or three-dimensional thread profile creation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a confocal sensor is used to measure internal threads, then measurement precision is improved, but the device complexity and installation space requirements increase due to complex tactile centering mechanisms
Solution Approach 1:
The patent replaces complex mechanical tactile centering mechanisms with an optical centering approach. A camera captures images of the internal thread, and image processing algorithms automatically determine the thread center and geometry, eliminating the need for complex mechanical adjustment mechanisms while maintaining high measurement precision.
Solution Approach 2:
The patent creates an optical copy (image) of the internal thread using a camera instead of direct mechanical contact. This optical copy is then processed to extract thread parameters, avoiding the need for complex mechanical centering tools and reducing device complexity while maintaining measurement accuracy.
2Measurement precision
If multiple actuators are used to adjust the sensor position and orientation, then measurement accuracy is improved, but the installation space and device complexity increase
Solution Approach 1:
The patent employs a single multi-functional optical sensor unit that integrates multiple capabilities (distance measurement, image capture, focus adjustment) into one component. This universal sensor replaces multiple separate actuators and mechanisms, reducing installation space while maintaining the ability to accurately measure complex thread profiles through coordinated optical adjustments.
3Device complexity
If a fixed-angle sensor field of view is used, then device simplicity is maintained, but the ability to scan conical and undercut threads efficiently is reduced
Solution Approach 1:
The patent introduces dynamic adjustment capability to the sensor system, allowing the field of view angle and sensor orientation to be changed during operation. This enables efficient scanning of conical and undercut thread geometries by adapting the optical parameters to match the thread shape, significantly improving measurement productivity while maintaining reasonable device simplicity through software-controlled adjustments rather than complex mechanical systems.
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 system allows for accurate and efficient optical measurement of internal threads, particularly in pipes with small inner diameters, reducing measurement time and improving precision while being compact enough for use in constrained spaces.
Implementation Method 1
at least one further optical element which is adjustable relative to the optical sensor and which is arranged at a specific distance from the sensor in an optical axis on an optical bench and is designed to optically scan the internal thread
Implementation Method 2
The sensor is designed as a confocal sensor
Data Source
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AI summary
The invention relates to an arrangement (1) and a method for optical measurement of a thread, in particular for measurement of an internal thread (12) on a sleeve or on a sleeve end of a metal pipe (11), wherein the arrangement (1) comprises at least one optical sensor (5), at least one further optical element that can be adjusted relative to the optical sensor (5) and that is arranged on an optical bench (3) at a determined distance from the sensor along an optical axis (7) and is designed for optically scanning the internal thread (12), as well as means for acquiring and/or storing and/or evaluating the measurement data recorded by the sensor.