Eddy Current Sensor Position-Based Sampling for Steam Generator Tube Inspection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Eddy current sensors in steam generators are prone to damage during inspections due to rapid acceleration and deceleration, leading to costly replacements and inaccurate data collection, especially when not traveling at a consistent velocity, which complicates comparison with historical data and may require repeated inspections.
Innovation Solution
An improved method and system that accelerates and decelerates the eddy current sensor in a controlled manner, using an encoder to record signals at equally spaced locations along the tube, allowing for variable velocity without compromising data validity, and employing a drive mechanism with rollers and motors to minimize sensor impact and ensure accurate data collection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the eddy current sensor is rapidly accelerated from a standing stop to reach fixed velocity by the time it reenters the tube, then the detection pass can be performed at a fixed velocity with consistent data sampling, but the eddy current sensor can impact the tube sheet and bend, resulting in damage to the sensor
Solution Approach 1:
The patent applies dynamics by transitioning from fixed velocity sampling to variable velocity sampling. The system dynamically adjusts the sampling rate based on the actual probe velocity at any given moment, allowing the probe to accelerate and decelerate naturally while maintaining accurate data collection. This resolves the contradiction by enabling both high inspection speed and sensor durability without requiring rapid acceleration to fixed velocity.
Solution Approach 2:
The patent changes the parameter of velocity from a fixed constant to a variable parameter that fluctuates during inspection. By recording velocity information alongside eddy current data and using this variable velocity information to space data points equally along the tube length, the system eliminates the need for rapid acceleration to maintain consistent sampling, thereby protecting the sensor while preserving inspection productivity.
2Reliability
If the eddy current sensor travels at variable velocity through the tube, then the inspection can be performed without damaging the sensor, but the recorded data points are not equally spaced along the tube making comparison with historical data difficult
Solution Approach 1:
The patent transforms the data spacing from time-based to position-based by incorporating velocity measurements. The system records the actual velocity of the probe at each sampling moment and uses this information to calculate the physical distance between data points along the tube. This allows variable velocity operation while maintaining equally spaced data points in the final dataset, enabling accurate comparison with historical data while preserving sensor durability.
Solution Approach 2:
The system implements feedback by continuously monitoring probe velocity and using this information to adjust data sampling and spacing. The velocity measurements feed back into the data processing system, which then spaces the eddy current data points equally along the tube length based on actual travel distance. This feedback mechanism ensures measurement precision is maintained even though the sensor travels at variable velocity throughout the inspection.
3Device complexity
If fixed time interval sampling is used during detection pass, then data collection is simple and consistent, but the eddy current sensor must be maintained at fixed velocity which requires rapid acceleration and increases risk of sensor damage
Solution Approach 1:
The patent changes the sampling parameter from fixed time intervals to variable time intervals based on actual velocity. Instead of sampling at constant time intervals which requires fixed velocity, the system samples based on position along the tube using velocity information. This eliminates the need for rapid acceleration to maintain fixed velocity while keeping the sampling system relatively simple through the use of velocity-based triggering.
Solution Approach 2:
The system applies dynamics by making the sampling rate adaptive rather than static. The sampling frequency dynamically adjusts according to the probe's actual velocity, allowing the system to operate without maintaining fixed velocity. This dynamic approach eliminates the harmful acceleration impacts while preserving data collection consistency through position-based equal spacing of samples.
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 approach reduces sensor damage, minimizes radiological waste, and enhances data accuracy by allowing for reproducible and accurate eddy current signal recording, reducing the need for repeated inspections and associated costs.
Implementation Method 1
a probe having an eddy current sensor is moved through a tube of the steam generator while the response signal from the eddy current sensor is sampled and recorded
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method of employing an eddy current sensor to perform an inspection of a tube of a steam generator involves accelerating and decelerating the eddy current sensor in a predetermined fashion that substantially reduces the likelihood of damage to the eddy current sensor. The reduction of probe stresses reduces radiological waste and reduces radiation exposure to workers involved in changing damaged probes The recording of an eddy current signal at each of a plurality of equally spaced apart locations along the tube permits the velocity of the eddy current sensor to be varied without compromising the validity of the data that has been recorded. The inspection system employs an encoder that outputs a series of signals as the probe is advanced incremental distances within the tube of the steam generator, and eddy current sensor signals are recorded responsive to at least some to be signals from the encoder.