Steam Generator Insertion-Hole Blockage Rate Evaluation
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Solution Overview
Problem
The existing methods for evaluating the blockage rate of insertion holes in steam generators require frequent visual inspections and re-creation of evaluation curves, which are time-consuming and labor-intensive due to limited access and the complexity of the steam generator's internal structure, leading to inaccuracies and high costs.
Innovation Solution
A system that includes an evaluation-curve updating unit, blockage-evaluation-value calculating unit, estimated-blockage-rate calculating unit, and blocked-state assessing unit, which uses ECT waveforms and visual inspection data to create an updated evaluation curve, allowing for accurate and efficient assessment of blockage rates by interpolating missing data and predicting future blockage states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If visual inspection is performed every time the steam generator is inspected to re-create the evaluation curve, then the accuracy of the evaluation curve is improved, but the time and labor required increase considerably
Solution Approach 1:
The patent performs visual inspection and ECT measurement at the time of steam generator commissioning to establish an initial evaluation curve. This preliminary action allows the evaluation curve to be created once with high accuracy, eliminating the need for repeated visual inspections at subsequent inspection cycles. The evaluation curve is then used to assess blockage rates at later times without requiring re-creation.
Solution Approach 2:
The patent uses ECT (Eddy Current Testing) measurements as a non-contact copying method to assess blockage rates without physically entering the steam generator. The ECT probe measures electrical conductivity changes caused by scale deposition, creating a virtual representation of blockage conditions. This allows repeated assessments without repeated physical visual inspections, reducing time and labor while maintaining accuracy.
2Measurement precision
If visual inspection is performed to re-create the evaluation curve, then the accuracy of blockage rate evaluation is improved, but the device complexity and difficulty of access increase
Solution Approach 1:
The patent introduces ECT (Eddy Current Testing) as an intermediary measurement method between the external inspector and the internal blockage conditions. The ECT probe, accessible from external maintenance openings, measures electrical conductivity changes in the steam generator interior caused by scale deposition. This intermediary method eliminates the need for direct visual inspection inside the steam generator, overcoming the access difficulty while maintaining measurement accuracy.
Solution Approach 2:
The patent replaces the mechanical visual inspection system (requiring physical entry, cameras, and direct observation) with an electrical measurement system (ECT). The ECT probe measures blockage rates through electrical conductivity changes induced by eddy currents, substituting mechanical access requirements with electrical field penetration. This allows accurate blockage assessment through existing maintenance openings without complex mechanical inspection equipment.
3Reliability
If frequent visual inspections are performed, then the reliability of blockage rate assessment is improved, but the cost increases
Solution Approach 1:
The patent performs the comprehensive visual inspection and ECT measurement combination only at commissioning to establish the initial evaluation curve. This preliminary action captures the baseline blockage conditions and creates a reference for future assessments. Subsequent inspections can rely on this pre-established curve, eliminating the need for repeated expensive visual inspections while maintaining reliable blockage rate assessment through ECT measurements.
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 enables easy and accurate assessment of blockage rates, reducing the time and labor required for evaluations, lowering costs, and increasing the frequency of assessments, thereby improving the operational efficiency of steam generators.
Implementation Method 1
a method of estimating the blockage rate based on an eddy current testing signal acquired by using an eddy current testing (ECT)
Data Source
AI summary
An insertion-hole blockage-rate evaluation system is applied to a heat exchanger that includes a heat transfer tube and a tube support plate having an insertion hole formed therein for inserting the heat transfer tube therethrough. The tube support plate is displayed in a three dimensional manner in an elliptical diagram with a ratio between a long axis and a short axis being in a range from 1.0 to 2.0 inclusive, each of the tube support plates is serially arranged so as not to overlap on each other, and the insertion-hole blockage-rate evaluation system includes an imaging process of color-coding and displaying the diagram displayed in the three-dimensional elliptical shape according to a value of a blockage rate of the insertion hole acquired by checking the blockage rate of the insertion hole.