光纤压差传感器

本文研究的一种实用的光纤压差传感器,通过共光源双膜片结构保证了稳定性,采用波纹膜片得到较高灵敏度.该传感器已用于充压检漏系统,其灵敏度达到56050mV/MPa.零漂小于0.1mV/h,热灵敏度漂移为0.013%/℃.     

光纤传感监测压力管道泄漏技术进展综述

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。     

一种基于物联网技术的氦质谱检漏系统

针对现有氦质谱检漏系统的技术缺陷,提出了一种基于物联网技术的氦质谱检漏系统的设计与实现方案。该系统综合了嵌入式与ZigBee、WiFi等物联网技术,由主控模块、采集模块、执行模块等组成;主控模块可实时整合氦质谱检漏仪与采集模块的数据信息,控制执行模块自动完成检漏流程,并利用灰度算法预测检漏信号的稳定时机,提高了检漏效率,测试结果验证了该方案的有效性。     

气密检漏泄漏量测试系统的设计

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。     

基于LabVIEW的直压检漏系统温度影响试验研究

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.     

煤矿瓦斯抽采管网系统自更新检漏技术研究

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。     

基于DSP的航天器压力变化检漏仪的设计

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。     

浙江义乌投资教育科研网

日前,AMP 公司在浙江义乌市教育科研网布线工程招标项目中成功中标。此科研网由义乌市教委统一实施,旨在改善及提高义乌市的教育科研硬环境,为各项先进的教育软件的应用提供配套的网络连接系统。AMP 的超五类110系统及光纤系统中标。其中 AMP 的光纤压接技术尤其引起用户的关注。此项目完工后将为义乌市教育科研院所提供一套有效的、快速的完善的网络连接系统。     

国外展望

采用光纤通讯技术的分布式检测系统美国巴顿仪表公司研制的分布式检测系统采用了智能变送仪表和光纤通讯设备。这种型号为DMX-1000的分布式检测系统由一部主站、手操通讯器、星形光耦合器以及智能化变送器组成。工作人员利用手操通讯器可远距离地调整变送器的工作范围、量程、阻尼常数以及输出信号的形式。它还可以加入一个标定输入来检校仪表。系统中包括各种检测流量、液位、温度、磁通量、绝对压力、表压及差压的变送器。除电磁流量变送器外,其它变送器均用电池供电。系统内的全部通讯是靠一根光缆、并采用多路转换     

基于信息融合算法的管道泄漏检测技术研究

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。     

A field implementation of linear prediction for leak-monitoring in water distribution networks

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.     

微弯光纤传感器位移灵敏度研究

根据光纤模式耦合理论,光纤微弯时光纤中的传输光有光功率损耗,对微弯光纤传感器出射光强进行分析、测量,实验得出了位移灵敏度与微弯周期的关系,对应用微弯光纤组成分布式光纤测试系统的传感器具有重要意义。     

虚拟仪器技术在光模块自动测试系统中的应用

研究了虚拟仪器技术在光通信产品参数测量过程中的应用。光模块是光纤通讯收发端光电转换器和电路控制嚣的组合，其作用是实现光／电信号的转换。采用虚拟仪器技术组建光模块测试系统具有开发周期短、成本低的特点．同时又具有很强的兼容性和扩展性，能够大大缩短光模块主要参数的测试时间、简化测试过程以及实现测试过程的自动化。     

基于双目视觉的光纤定位研究

本文介绍了一种在光纤对接系统中用于光纤粗定位的视觉子系统．文章以双目视 觉的应用为背景，详细论述了视觉系统的硬件配置和软件开发，包括系统标定、图象处理、 特征提取、三维计算的具体步骤．提出了改进的Hough变换算法，能够较为准确的定位图象 中的两根光纤．     

Two-dimensional monomode optical fibre array manufacture using microengineering techniques

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.     

Two-dimensional monomode optical fibre array manufacture using microengineering techniques

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.

     

Optimisation of the range of an optical fibre pH sensor using feed-forward artificial neural network

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.     

Leak detection in an experimental heat exchanger process: amultiple model approach

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     

EDS在配电自动化系统中的应用

通过对传统的光纤以太网通信方式的分析,根据配电自动化系统的特点,设计出用以太网设备服务器或交换机EDS代替光纤收发器或光端机的新型通信方案。侧重介绍了EDS的特点以及基于EDS的配电自动化系统光纤以太网的组网方法。研制的嵌入该新型通信方式的配电自动化系统产品已投入现场运行。实践证明,其性能优越,技术先进。     

井下胶带接头图像采集系统设计

针对现有胶带接头隐患检测方法存在漏检、误报等问题,设计了一种井下运输胶带接头的图像采集系统。该系统采用电感式接近开关实时检测金属胶带接头,并控制数字摄像机自动抓拍运输胶带接头处的图像,利用井下环网将图像传输到地面监控室,实现胶带接头图像的实时采集与处理,及时排除胶带接头可能出现的撕裂、脱扣等隐患。