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有效预防并解决长输压力管道在运行中发生的泄露和爆管故障是传输工程中的一大技术瓶颈。近几年,刚兴起的光纤传感技术在压力管道检漏方面的应用相比于传统检测方法有着诸多的优势。光纤传感监测管道泄露的技术主要分为分布式与准分布式两大类,结合国内外压力管道检漏技术的发展现状,分别论述分布式与准分布式光纤传感技术在压力管道检漏方面的应用。 相似文献
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介绍了一种基于直压检漏法和红外皂膜流量计技术设计的智能检漏泄漏量测试仪器,这种仪器兼备检漏测试和泄漏量测试的功能;通过分析可消除自然光直流干扰的皂膜检测调理电路的工作原理,简化了皂膜计的结构,并且论述了泄漏量检测原理、气路设计、硬件电路和软件设计,设计出检漏泄漏量测试为一体的高精度、便携式的检漏泄漏量测试仪器。 相似文献
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介绍基于LabVIEW软件开发平台的直压检漏系统组成及工作原理.建立了描述直压检漏系统被测容腔内气体压力、温度以及等效传热系数、漏率之间关系的数学模型.基于该模型并根据试验实际所测压力和温度数据获得等效传热系数和漏率在不同温度变化过程中的变化规律.试验结果表明,负压状态下被测容腔内气体压力、温度和泄漏量相互影响,微泄漏对容腔内气体的温度变化影响较小,容腔漏率随容腔内气体压力和温度升高而变小,随容腔内气体压力和温度降低而变大.等效传热系数随容腔内气体温度上升和容腔内外温差增大而减小,随容腔内气体温度下降和容腔内外温差减小而增大.本研究为直压检漏系统温度校正深入研究奠定了一定的基础. 相似文献
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煤矿井下工作环境恶劣,瓦斯抽采管道易受到碰撞、落煤坠砸等损伤而造成漏气,当巷道内空气大量进入管网系统后,管网内瓦斯抽采浓度可能远低于钻孔孔口浓度。针对该问题,提出了一种基于多元高斯声束模型的煤矿瓦斯抽采管网系统自更新检漏技术。采用多元高斯声束模型对漏气点声音进行加强处理,并分析煤矿井下抽采管网系统的主要漏气类型和噪声来源,建立漏气模型和噪声模型;将采集的声音样本与预存模型进行比对,判断是否存在漏气现象,并将使用环境中出现频率超过30%的声音样本自动存储为漏气模型,实现模型的自动更新,提高检漏准确性;基于自更新检漏技术研发了YJL40检漏仪,其主要部件包括探测头、金属软管、主机和报警器。利用自更新检漏技术及相应产品对高家庄煤矿的高、低负压抽采系统共计7 585m管道进行检漏,将检测出的漏气点进行有效封孔后,抽采终端瓦斯体积分数分别提高了37.1%和28%,验证了自更新检漏技术的有效性。 相似文献
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航天器的密封性能是极其重要的指标之一,利用压力变化方法进行舱体密封性检漏是保障其密封性的重要技术手段;设计研制小型压力变化检漏仪对满足航天器检漏设备小型集成化、高精度的迫切需求是十分重要的;以DSP为数据的核心处理器,分析绝压和差压具有温度补偿方法,设计基于485通信接口实现数字绝压传感器的数据采集,采用250Ω的高精度电阻接入电流环的方法实现差压传感器的信号调理,通过ADS1247高精度24位数模转换器实现差压信号的采集;并采用恒流供电和电阻比测量原理实现对两路热敏电阻温度传感器的测量;各信号经DSP中固化的压力变化检漏算法集中处理,得到被测物体的漏率值,检测结果通过LCD显示;所研制集绝压、差压和温度多参量监测于一体的检漏仪,经过温度、压力、检漏试验等测试,验证了其精度和检漏能力满足要求;研究结果表明:所研制的检漏仪小巧,精度高,可靠性高,可实现压力、温度、漏率等多参量的同时监测,漏率检测的最大相对误差为19.3%,相对不确定度小于2%,可有效地解决航天器泄漏检测的问题。 相似文献
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基于目前已经在石油输送管道中应用的SCADA系统,将信息融合技术应用于管道泄漏检测系统中;该方法应用管道泄漏时的多种特征信号,采用最优加权融合算法将多元信息综合处理,扩展了时间和空间上的检测范围,提高了泄漏检测系统的灵敏度和可靠性。在实验室用水泵和不锈钢管道组成的水循环系统进行了模拟实验,通过对比验证了信息融合检漏方法比单一检漏方法具有明显的优越性。 相似文献
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Water distribution networks (WDNs) are complex systems that are subjected to stresses due to a number of hydraulic and environmental loads. As a result, system leaks remain an unavoidable reality. Leaks which are not large enough to become visible at the street level can often go undetected for prolonged periods of time; the presence of smaller leaks can be concealed in system variability. The current paper addresses the problem of leak-detection and localization in WDNs, using a data-driven methodology which utilizes linear prediction (LP) theory. LP has a relatively simple mathematical formulation and has been shown in laboratory studies to effectively capture leak-induced signatures in fluid-filled pipes. In this paper, the performance of LP for leak-detection is verified, using field data in an operational WDN. In addition, a two-part localization approach is proposed which utilizes LP pre-processed data, in tandem with the traditional cross-correlation approach. Results of the field study show that the proposed method is able to perform both leak-detection and localization in full-scale systems using relatively short time signal lengths. This is advantageous in continuous monitoring situations as this minimizes data transmission requirements, which are one of the main impediments to full-scale implementation and deployment of leak-detection technology. In addition to the analysis results, a novel hydrant-mounted data-acquisition system is proposed, along with its unique hardware and software capabilities. 相似文献
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A method to manufacture two-dimensional bundles of optical single mode fibres is described in this article. Submicron translational alignment accuracy is being implemented by this method. An array of micro holes, each surrounded by four electrodes was produced using the Lithographie Galvanoformung Abformung process. Electrostatic fields between the electrodes and a metal coated optical single mode fibre inserted into such a hole were used to position the fibre inside the hole. By combining electrostatic movement and optical monitoring of the actual fibre position in a closed loop feedback alignment system high positioning accuracy can be realised. 相似文献
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A method to manufacture two-dimensional bundles of optical single mode fibres is described in this article. Submicron translational alignment accuracy is being implemented by this method. An array of micro holes, each surrounded by four electrodes was produced using the Lithographie Galvanoformung Abformung process. Electrostatic fields between the electrodes and a metal coated optical single mode fibre inserted into such a hole were used to position the fibre inside the hole. By combining electrostatic movement and optical monitoring of the actual fibre position in a closed loop feedback alignment system high positioning accuracy can be realised.
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An application of a multiple model nonlinear filtering technique is discussed for the detection of leaks in a heat-exchanger process. The results of simulation study and an experimental study on a laboratory heat-exchanger process are presented. A simple decision logic scheme (threshold crossing) is used to process the outputs of the leak-detection algorithm to indicate the status of the process, i.e. whether or not there is a leak. The results of the study provide preliminary indication of the feasibility of the proposed diagnostic technique to detect small leaks in an experimental heat-exchanger process. The study also indicates that the technique is robust in the midst of significant flow disturbances on the inlet water flow, using only simple models for processing of the outlet temperature data, but is sensitive to the aggregate heat transfer parameter used in the detection algorithm 相似文献
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Optimisation of the range of an optical fibre pH sensor using feed-forward artificial neural network
Faiz Bukhari Mohd Suah Musa Ahmad Mohd Nasir Taib 《Sensors and actuators. B, Chemical》2003,90(1-3):175-181
A broad range of optical fibre pH sensor based on immobilised bromophenol blue (BPB) immobilised on hydrophobic organic polymers Amberlite XAD 7 is presented in this paper. The reflectance spectra of the immobilised bromophenol blue were measured by using an optical fibre spectrophotometer. A back-propagation (BP) artificial neural network (ANN) model was used to analyse the optode response. The results showed that the use of ANN technique was very effective in broadening the limited dynamic response of the pH sensor (pH 2.00–5.00) to an extensive calibration response (pH 2.00–12.00). A network with 11 neurons in the hidden layer was tremendously accurate in predicting the response of the optical fibre pH sensor with an average error 0.02 pH for measuring unidentified buffer solution. 相似文献