Ultrasonic Thickness Inspection via Pulse Compression
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Solution Overview
Problem
Current ultrasonic thickness reduction inspection methods are inefficient for detecting moderate pipe thickness reduction, particularly in nuclear power plants, as they require insertion of inspection pigs and struggle to detect FAC-induced thickness changes due to lack of reflection of ultrasonic waves.
Innovation Solution
An ultrasonic thickness reduction inspection method using a plurality of sensors on the pipe surface that employ pulse compression wave signals and cross-correlation processing to detect changes in pipe thickness without inserting an inspection pig, allowing for efficient detection of moderate thickness reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional ultrasonic inspection methods are used to detect pipe thickness reduction, then inspection coverage can be achieved, but inspection efficiency is low and labor costs are high due to requiring scaffolding and heat insulating material removal
Solution Approach 1:
The patent replaces the conventional mechanical contact ultrasonic inspection method (requiring scaffolding and material removal) with a non-contact optical measurement system using laser or structured light to scan the pipe outer surface, thereby eliminating the need for physical access preparation and significantly improving inspection efficiency
Solution Approach 2:
The patent introduces an intermediary computational model that correlates pipe outer surface geometry with inner wall thickness, allowing thickness reduction detection without direct contact with the pipe interior, thus avoiding the need for scaffolding and heat insulating material removal
2Measurement precision
If pulse ultrasonic waves are used for thickness measurement, then thickness reduction can be detected, but moderate thickness reduction caused by FAC cannot be detected since ultrasonic waves are not reflected
Solution Approach 1:
The patent substitutes ultrasonic wave-based detection with optical measurement technology that scans the pipe outer surface to detect geometric changes, enabling reliable detection of moderate thickness reduction caused by FAC without relying on ultrasonic wave reflection
Solution Approach 2:
The patent changes the detection parameter from ultrasonic wave reflection characteristics to optical surface geometry parameters, allowing detection of thickness reduction through surface profile analysis rather than acoustic signal analysis
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 efficient inspection of pipe thickness reduction occurrence and distribution without inserting an inspection pig, effectively detecting FAC-induced changes and reducing labor and time costs.
Implementation Method 1
a plurality of ultrasonic sensors is excited by a pulse compression wave signal, ultrasonic waves are supplied in the inspection target
Implementation Method 2
signals in which the plurality of ultrasonic sensors is excited by a plurality of echoes from the inside of the inspection target by the ultrasonic waves supplied
Implementation Method 3
the plurality of ultrasonic sensors is excited by a pulse compression wave signal
Implementation Method 4
from cross correlation between signals summing the plurality of echo signals and the pulse compression wave signal, a time difference between a first peak of the summed signal and a first peak of the pulse compression wave signal
Data Source
AI summary
Chirp waves generated in a transmitting/receiving unit is supplied to ultrasonic sensors. Signals output from the ultrasonic sensors are supplied to the transmitting/receiving unit and summed in a signal processing/recording unit. The signal processing/recording unit performs mutual correlation processing between the summed signals and the chirp waves and calculates a peak generation time difference. Necessity of exchanging a pipe is determined by calculating and recording the thickness of a pipe from the calculated time difference and calculating a difference between thicknesses measured in the past and the present.