基于交变漏磁的裂纹检测系统

交变漏磁检测技术结合了涡流检测和漏磁检测的优点,它可以实现对铁磁性材料表面裂纹的准确检测.文中介绍了交变漏磁检测的原理以及裂纹检测系统的软硬件设计.通过试验研究,依据检测的两路信号及其构成的缺陷环图,可以实现对裂纹缺陷的检测.     

管道外漏磁检测技术研究

为了防止管道在生产运行中发生严重的腐蚀导致泄漏,造成重大生命财产损失,依据管径尺寸不同、曲直走向不同和可拆卸程度不同等特点,将管道检测方法细化,基于漏磁检测原理,提出了适用于不同工况下的可变径磁化、整体磁化、局部磁化和直流磁化等管道外漏磁检测方法。设计出适用于大管径检测的可变径漏磁检测仪、适用于直管的整体磁化管道外漏磁检测仪、适用于小管径的局部磁化漏磁检测仪和适用于可拆卸管道的电磁磁化漏磁检测仪,研究4种检测方法对现场管道腐蚀缺陷进行检测的可行性。结果表明,管道外漏磁检测方法可以对管道进行检测和评价,也可以为管道的维修和管理提供决策依据。     

长输油气管道漏磁内检测技术

长输油气管道在油气能源运输中发挥着关键作用,被称为"能源血脉"。为保证管道的安全有效运行,应定期对管道进行检测。管道漏磁内检测技术是目前国内外长输油气管道内检测领域普遍应用的检测技术,该技术以管道管体已形成的体积缺陷为检测目的,可以准确检测出缺陷面积、程度、方位等信息。对油气管道漏磁内检测技术原理和影响因素等进行归纳总结,阐述了管道漏磁内检测中轴向励磁和周向励磁等关键技术的国内外研究现状,对国内外漏磁内检测器的检测能力进行对比,介绍了漏磁信号的处理方法及管道的完整性评价技术,最后提出了管道漏磁内检测行业的未来展望。     

漏磁传感器励磁结构影响因素分析及优化设计

漏磁检测中励磁结构的磁化能力是影响漏磁传感器缺陷检测能力的一个重要因素。根据交流漏磁检测原理,建立二维漏磁检测参数化有限元仿真模型,研究磁心的形状和尺寸、励磁线圈的位置和绕组长度、磁屏蔽层厚度等励磁结构参数对漏磁检测信号的影响。同时,将参数化有限元分析与遗传优化算法相结合,发展一种励磁结构尺寸参数的有限元模拟遗传优化设计方法,实现了漏磁传感器中磁极间距与磁极宽度等关键尺寸的优化。仿真及检测试验结果表明,传感器的励磁结构参数对漏磁检测结果具有很大影响,优化后的励磁结构可有效提高漏磁传感器的缺陷检测性能。提出的基于参数化有限元的遗传优化方法为漏磁检测中其余影响参数的优化提供了可行的参考方法。     

基于三维漏磁测量的腐蚀检测探头设计

在传统一维漏磁检测的基础上,为了获取更多特征信息以提高漏磁检测对缺陷的识别能力,提出了三维漏磁检测新方法.较传统一维检测,三维漏磁检测对信号采集系统有着更高的要求,本文适时提出了一种适应三维漏磁检测的磁场测量探头的设计方案,并已经在实验现场得到应用.     

高清晰度漏磁检测器的研制及应用

石油天然气管道输送在国民经济中占有极为重要的战略地位,为确保输油气管道的安全运行,国内外正在积极推行管道完整性管理的理念。管道检测是完整性管理的重要组成部分,工业发达的国家均高度重视油气管道检测技术的研究和应用。本文简要介绍了漏磁检测技术的原理,以及高清晰度漏磁检测器的系统结构。     

基于三维场测量的脉冲漏磁检测技术

漏磁检测广泛应用于铁磁性材料缺陷检测.脉冲漏磁检测技术是一种新型电磁无损检测技术.缺陷的定量评估是无损检测的重要步骤之一.运用有限元法对管道周向外壁缺陷的漏磁场进行瞬态分析,分析了缺陷脉冲漏磁场Bx、By和Bz三维分量的分布特点,最后给出了仿真结果和试验结果,试验结果和仿真有很好的一致性.试验结果表明:综合脉冲漏磁场的三维峰值扫描电压可以对缺陷的长度和宽度进行检测,而三维分量差分信号中的过零时间随缺陷的深度变化而变化,且不随缺陷宽度的改变而改变,由此可以检测缺陷的深度.三维脉冲漏磁检测系统使缺陷的定量检测有了可能.     

钻杆管体的漏磁检测

常见的井下钻具事故多是由于疏于检测致使有严重缺陷的钻具下井造成的。基于漏磁工作原理的探伤机,可以有效检测出存在缺陷的钻具,以减少事故隐患。本文系统探讨了漏磁检测技术在钻杆管体探伤过程中的应用问题。     

管道缺陷漏磁检测信号的仿真

漏磁检测是管道无损检测的常用方法,也是最有效方法之一.在检测管道的过程中,对于不同的缺陷会检测到不同的漏磁信号.通过建立管道检测的实体模型,对管道斜向裂纹缺陷所产生的漏磁信号运用ANSYS有限元软件进行模拟仿真,从仿真信号中的磁通密度纵横向矢量图中,直观地显示了漏磁场附近的特点,找到缺陷轮廓及参数.利用有限元可以分析出,缺陷漏磁场的峰值会随着裂纹的倾斜角度、宽度、深度、提离值的大小变化而变化,可以方便地建立大量大小不一形状不同的缺陷样本库,为缺陷的识别提供依据并为定量分析做准备,为进一步对漏磁场的研究打下基础.     

第1届上银优秀机械博士论文奖

钢管漏磁检测新原理及其应用作者:孙燕华毕业学校:华中科技大学指导教师:康宜华作为一种高效的无损检测方法,漏磁检测已被广泛应用于各种铁磁性材料的缺陷检测与评估中,特别在自动化钢管探伤上优势显著。迄今为止,漏磁检测研究已接近100年,随着探伤需求的增加,检测指标的提高,漏磁检测方法的深入研究和新原理的发现具有重要的理论意义,同时也是寻求钢管漏磁无损检测新方法的途径之一。     

State of the art of in-line nondestructive weld inspection of pipelines by ultrasonics

The in-line inspection of pipelines via the use of intelligent PIGs (pipeline inspection gages) that concerns the detection and sizing of metal loss (e.g., caused by corrosion) is a well-established technology for liquid pipelines as well as gas pipelines. Magnetic flux leakage and ultrasonic techniques are used for inspection. The application of conventional ultrasonic techniques is normally restricted to liquid lines because a liquid coupling medium is required. For reliable crack detection, only the ultrasonic technique has proven suitable. The cracking in pipelines is induced by fatigue crack growth and stress corrosion cracking in addition to manufacturing-related phenomena. The state of the art of in-line crack inspection is discussed, especially as regards typical examples of weld inspection. Special emphasis is placed on data evaluation and interpretation. The text was submitted by the authors in English.     

Prediction method of ball valve internal leakage rate based on acoustic emission technology

Valves on natural gas transmission pipelines are prone to internal leakage due to the influence of environment, transportation medium, misoperation and other factors. Therefore, timely and accurate detection of valve internal leakage is of great significance to the safe operation of the pipelines. As a non-destructive testing method, acoustic emission (AE) technology can be used for online detection of internal leakage of valve. In order to improve the accuracy of AE technology for detecting valve internal leakage, a ball valve internal leakage detection method based on acoustic emission technology is proposed. Firstly, the AE signal generated by the internal leakage of the ball valve is detected by AE sensor, and the AE signal is denoised by wavelet packet threshold denoising. Secondly, the characteristic parameters with high correlation with the internal leakage rate of the ball valve are selected by using the correlation coefficient method to form the sample feature set. Finally, the mathematical model between the internal leakage rate of the ball valve and the characteristic parameters is established by using the sparrow search algorithm to optimize the backpropagation neural network, and to predict the internal leakage rate of the ball valve. An experimental platform is built to verify that the proposed method can predict the internal leakage rate of the ball valve more accurately. It provides strong technical support for the safe operation of natural gas transmission pipelines.     

基于瞬态压力波法的输油管道泄漏检测技术研究

近年来,油管道泄漏事故频繁发生,为保障管道安全运行和将泄漏事故造成的危害减少到最小,需要研究泄漏检测技术以获得更高的泄漏检测灵敏度和定位精度。针对输油管道的特点,分析了瞬态压力波泄漏检测技术的定位原理以及影响准确定位的关键因素,对热油输送管道沿程瞬态压力波传播速度的变化进行了研究。另外利用信号奇异点与小波变换模极大值在多尺度上变化对应的性质,将小波变换应用到扑捉泄漏压力信号序列的特征拐点中,使压力波时间差更加精确,从而有效提高了输油管道泄漏检测的定位精度。     

基于图像处理的工业阀门气体泄漏监测法

目前监测工业阀门气体泄漏的方法多种多样,但是采用图像处理技术的比较少,虽然现场安装了工业摄像头,但是也只能在监控室进行人工监控。本文采用大恒图像提供的工业智能摄像机和云台组成的CCD光学监控系统,结合相关的分析软件进行在线监测,并且利用图像处理技术设计了相应的气泄漏监测系统。通过对阀门背景图像的采集,对图像进行增强、滤波等处理后能较好的识别、判断出阀门发生泄漏的情况,这为泄漏检测、监测的新技术奠定了一定的基础,也使图像技术更好、更广泛地应用于工业生产中。     

基于DSP和LabVIEW的管道大型漏磁检测系统开发

本文综述了国内外管道漏磁检测系统发展现状：针对目前存在的主要问题，鉴于数宇信号处理器以及虚拟仪器开发环境的特点，研究了利用DSP和LabVIEW开发管道漏磁检测的大型可视化系统的可行性，并提出了系统实现的几种方法。     

Numerical study on leakage detection and location in a simple gas pipeline branch using an array of pressure sensors

Pressure signals measured in gas pipelines provide useful information for monitoring the status of pipeline network operations. This study numerically investigates leakage detection and location in a simple gas pipeline branch using transient signals from an array of pressure sensors. A pipeline network simulation model was developed and used to predict one-dimensional compressible flow in gas pipelines. Two monitoring methods were tested for leakage detection and location; these include cross-correlation monitoring and pressure differential monitoring. The performance and reliability of the two monitoring methods were numerically assessed based on simulation results for a simple pipeline branch operation with a prescribed leakage rate (5% of total flow rate in the gas pipeline).     

输油管道泄漏远程诊断方法研究

针对石油输送管道泄漏监测与诊断实时性要求高、数据传输量大、诊断原因复杂的特点,提出了一套基于SCADA框架下的远程化管道泄漏诊断的解决方案,即利用动态数据交换技术构造数据采集模块,获取远程实时信息,实现远程测试分析。介绍了管道远程化泄漏监测的基本概念,分析了管道远程化泄漏诊断系统的结构,在监测控制级设计了一个嵌入式泄漏诊断包,与Modbus协议的RTU数据包交互诊断结果信息,再通过光纤网络,实现了管道泄漏的远程智能诊断。应用结果表明,该方法可实现管道运行状态的全过程监测,提高了泄漏诊断的自动化水平,获得了较高的漏点定位精度。     

越野输油管道防漏盗监测系统的设计与实现

近年来我国各地越野输油管道由于自然和人为等因素，漏盗现象时有发生，造成了巨大的经济损失和环境污染，建立一个能够及时发现并准确定位的越野输油管道监测系统尤为迫切。针对越野输油管道数据监测的特殊要求．设计了基于分布式结构的数据采集系统。该系统以工控机为上位机，单片机集成系统为下位机，利用市话网作为数据传输媒介，实现了实时性较好的越野管道监测与控制。     

Design and experimental research of internal leakage detection device of buried pipeline ball valve based on valve cavity pressure detection

Valve is a key control component in the oil and gas long-distance pipelines, and the internal leakage detection of the valve has important research significance and application value. In this paper, a new method for detecting internal leakage of the buried pipeline ball valve based on the pressure change of the valve cavity was proposed. Firstly, a simplified internal leakage model of ball valve was established, and the change law of valve cavity pressure under different openings was obtained by finite element simulation. Secondly, a set of detection device was designed based on the internal leakage principle of buried ball valve and an experimental platform of ball valve internal leakage was built. Then, the pressure signal of the ball valve cavity under different openings and different pressures was collected by the pressure sensor, and the relationship between the power source pressure, the opening and the time required for the valve cavity pressure to reach equilibrium was established. Finally, the internal leakage degree of ball valve was simulated by ball valve opening and the Back Propagation (BP) neural network was selected to invert the ball valve opening. The inversion results showed that the maximum relative error of the liquid and gas experiment were 13.4% and 19.1%, respectively. The inversion results also verified the feasibility of BP neural network in the inversion calculation of the internal leakage degree of the ball valve, which provides guidance for the study of the classification of the internal leakage degree. The experiment and inversion results show that the proposed method can realize the detection of the internal leakage of the buried ball valve, which provides application reference in practice.     

载荷作用下管道漏磁内检测信号定量化研究

管道漏磁内检测技术是国际公认的长输油气管道安全维护的最有效方法。为解决载荷作用下长输油气管道漏磁内检测信号定量化问题,本文基于J-A理论建立了改进的三维磁荷数学模型,分析了管道缺陷在内压作用下的磁力学效应对漏磁信号的影响规律,研究了外部载荷作用下缺陷尺寸对漏磁信号影响规律,并通过系统的实验验证了理论模型的正确性。研究结果表明：管道内压增加,材料磁化强度减小,漏磁信号径向分量和轴向分量呈指数函数下降规律;漏磁信号径向分量峰值和轴向分量极大值随着缺陷深度增加而增加,增长率逐渐降低,特征值分别变化6.5%和14.7%;径向分量峰值增长率随长度增加而逐渐降低,轴向极大值线性减小,特征值分别变化21.0%和36.8%,轴向分量对缺陷深度和长度变化更敏感。