Non-Contact Optical Measurement of Threaded Joints
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Solution Overview
Problem
Existing measurement technologies face challenges in accurately and precisely measuring geometrical parameters of threaded connections, especially when coated, due to issues of misalignment, damage to coatings, and inability to measure parameters like taper, run-in, and run-out, and lack of non-destructive methods for coated threads in the hydrocarbon industry.
Innovation Solution
A method and device using non-contact optical sensors and a moveable mount to measure threaded objects, aligning them without manual adjustments, and calculating transformation matrices to determine relative positions, allowing for precise measurement of thread parameters before and after coating, including coating thickness, without damaging the coating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If contact-based measurement methods are used on threaded joints, then measurement can be performed, but the coating on the threads is damaged
Solution Approach 1:
The patent replaces contact-based mechanical measurement systems with non-contact optical measurement systems. The optical sensor captures images of the threaded joint without physical contact, eliminating mechanical damage to the coating while maintaining measurement capability for thread parameters such as pitch, depth, and profile.
Solution Approach 2:
The patent creates an optical copy (image) of the threaded joint surface and its threads. By capturing and analyzing images of the thread geometry, the system obtains measurement data without physically touching the coated surface, thus preserving the coating integrity while achieving precise dimensional measurements.
2Measurement precision
If manual alignment methods are used for measurement systems, then alignment can be achieved, but time is lost and precision is reduced
Solution Approach 1:
The measurement system automatically performs alignment through image processing and coordinate transformation algorithms. The system captures images, identifies thread features, and calculates the transformation matrix between coordinate systems without requiring manual intervention, thereby achieving both high precision and time efficiency.
Solution Approach 2:
The patent transforms the alignment problem from a manual mechanical adjustment task into an automated computational parameter transformation task. By using coordinate system transformation matrices calculated from image data, the system achieves precise alignment automatically, eliminating time-consuming manual operations while maintaining or improving precision.
3Measurement precision
If measurements are performed at the threading machine, then relative magnitudes can be measured, but the environment is hostile and alignment is difficult after removal
Solution Approach 1:
The patent extracts the measurement operation from the hostile threading machine environment and performs it in a controlled external environment. The threaded joint is measured after removal from the threading machine, in a stable laboratory or inspection setting, eliminating exposure to cutting oils, vibrations, and other adverse factors while maintaining measurement capability through non-contact optical methods.
4Measurement precision
If conventional measurement systems are used on coated threads, then thread parameters can be measured, but coating thickness and quality cannot be assessed
Solution Approach 1:
The optical measurement system performs multiple functions simultaneously: it measures thread geometric parameters (pitch, depth, profile) and assesses coating characteristics (thickness, uniformity, quality) from the same set of images. This multi-functional approach eliminates the need for separate measurement and inspection operations, providing comprehensive data on both thread geometry and coating 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
Enables precise, automatic, and non-destructive measurement of threaded objects, including coated ones, overcoming misalignment and coating damage issues, and providing accurate data on thread parameters and coating quality.
Implementation Method 1
a measurement device is provided that includes at least one optical sensor adapted to identify a shape of a threaded object
Data Source
AI summary
Thread parameters for a threaded object are determined. Spatial reference systems (X, Y, Z) and (X′, Y′, Z′) are respectively identified for a position sensor and the threaded object. A transformation matrix describing a quadratic form representing the threaded object in (X, Y, Z) may be determined to relate the reference systems. For example, a sensor trajectory on the threaded object may be determined, along with measurement points on the threaded object. The measurement points may be selected so the matrix, evaluated on these values, has maximum rank. Position data at measurement points in the second reference system may be transformed into the first reference system, yielding first results. After coating the threaded object, position data at the measurement points may be acquired again and transformed into the first reference system, yielding second results. Comparisons between the first and second results may provide thickness of the coating and quality verification.