- 期刊
遙場渦電統檢測訊號分析準則建立之研究
A Study on the Signal Analysis for Remote Field Eddy Current Testing
摘要
於煉油及石化工廠中，換熱器是一重要且不可缺少之設備，但換熱器管束常因腐蝕而造成洩漏，輕者使產品品質不良或換熱效率不佳，重者會導致非計畫性停?或工安事故。所以歲修中換熱器管束的腐蝕檢測是很重要的一環，本研究主要針對目前常用於鐵磁性管束（如碳綱管）檢查方法之一的遙場渦電流檢測技術加以進一步的研究，對於管壁厚度因素對檢測結果之影響情形做一些測試，並對於應用於現場檢測時此因素所造成研判之困擾情形建立一訊號分析研判準則，藉以加速訊號研判速度及減少訊號分析疑惑。由結果得知管壁厚薄情形影響訊號評估準確度很大，所以現場檢測時應對被測管子之厚度與標準管之厚度差異多加注意，否則易造會較大評估誤差，而延誤管子須汰換時機或因過度評估而浪費汰換管子的時間及金錢。而經由現場檢測之分析研判的實際驗證，已證明本研究所提供之分析研判準則已可幫助現場檢測人員突破分析研判上之盲點。
並列摘要
The heat exchangers are important and necessary equipments in petrochemical plants. The leakage accident of a corroded tube bundle in heat exchangers will usually reduce the product’s quality. In worst condition, it may cause unexpected plant shutdown and personnel injury. Therefore the corrosion detection in tube bundle of a heat exchanger is very important. This study focused on the use of remote field eddy current testing technology to inspect carbon steel tube bundle. We studied the effects of tube wall thickness on the result of inspection and established the signal analysis criteria to avoid the problem induced by the tube wall thickness variation. Using these criteria we can reduce the uncertainty in signal evaluation and reduce the analysis time. The experimental results show that the variation of wall thickness will affect the accuracy in signal evaluation. Large error of evaluation will result if the wall thickness difference between the inspecting tube and the calibration tube is not accounted for. And this error of evaluation may either delay the optimum time for retiring corroded tubes or spend much needless money and time to retire the soundness tubes. Through testing in the field we have verified the usefulness of the signal analysis criteria established in this study. These criteria can help inspector to solve the above-mentioned torment and drawback.