Safety Studies on Hydraulic Proportional Valves With Electrical Position Feedback

The authors analysed a proportional valve with electrical position feedback for its failure behaviour. Severalfailures were introduced into the feedback loop, especially into the 2 solenoids and the inductive positiontransducer. The behaviour of the valve for square and ramp reference signals was recorded and systematicallyanalysed. It was shown that failures could be detected by monitoring the residual signal from the equipmentunder control or the residual signal from the sensor. It was possible to achieve the safe position within twice thenormal response time of the valve by switching off the current of both solenoids. The application of these resultsfor a new generation of safe proportional valves is discussed. The use of the results of these investigationsobviates the need for redundancy of the electrical position monitoring arrangement in a safe proportionalvalve.     

At-risk behaviour analysis and improvement study in an academic laboratory

Academic laboratories contain inherently substantial risk conditions that students could expose to chemical and physical hazards. Procedures and guidelines related to laboratory safety are commonly available for students to adhere. However, many injuries and accidents or even fatalities are reported due to students’ violated safety practices while working in the laboratory. There was no reported proactive method or systematic technique to monitor and control students’ at-risk behaviour in the laboratory. This paper presented a program known as laboratory at-risk behaviour and improvement system (Lab-ARBAIS) to monitor and control students’ at-risk behaviours in the laboratory. Lab-ARBAIS used computer database for data acquisition and analysis on students’ at-risk behaviours observed. Pre-program questions on students’ at-risk behaviours that frequently violated safety regulations were utilized by observers to give observation feedback. The collected feedback was analysed and the results were posted in students’ portal to allow everyone to acknowledge their safety habits and practices. The routine observations and posted results are to instill a psychology effect in student’s habitual safety practices by reminding them on their frequently violated safety regulations. The implementation of the Lab-ARBAIS program to chemical engineering laboratory as a case study had shown a significant improvement on students’ frequent at-risk behaviours. The Lab-ARBAIS can easily be adopted in any academic laboratories to manage students’ at-risk behaviours to ensure safe work environment. With minor enhancement, the Lab-ARBAIS can easily be extended to be used in industrial laboratories.     

Priority analysis for risk factors of equipment in a hydraulic turbine generator unit

Ensuring the safe operation of hydropower stations is one of the key challenges for electric generation. Clearly the safe operation of such systems can only be archived with proper and effective maintenance scheduling. The objective of this study is to analyze, rank and prioritize the risk factors responsible for equipment failures of a hydraulic turbine generator unit (HTGU) based on operating data and expert elicitation. Here a simple qualitative risk evaluation model is proposed able to consider seven typical failures in HTGU. The proposed tool is applied for the risk prioritization of equipment failures, e.g. shaft torsion, misalignment, rotating fault, axis bend, runner fault, water guide, and wicket gate of a hydropower station in China. The obtained results have been compared against the actual statistics of equipment failures of a hydropower station in China, considered showing good agreement. All of these results provide theoretical guidance for digitalization realization of equipment failures.     

高处作业人员位置与生理信号相关性分析

为对高处作业人员位置状态进行识别,加强对高处施工人员作业状态的监控,采用VR技术模拟高处作业,同时利用人-机-环同步平台,采集平地处、一级高处作业(取4 m为例)以及二级高处作业(8 m为例)情景下的6种生理信号数据,运用SPSS软件对生理信号进行数据分析.结果显示,不同高处作业人员对皮电信号(EDA)的时域具有显著性...     

有限空间作业人员生理状态监测设备研制

为监测有限空间作业人员异常生理状况,进而保障有限空间作业安全与作业人员生命健康,在分析手腕处6个测量位置信号质量的基础上,获得最佳信号采集位置,并结合事故成因,从光电容积脉搏波(PPG)信号中提取心率、脉搏周期、振幅等生理参数作为评价指标,研制一款针对有限空间特殊作业人群的手腕处脉动生理信息监测设备;并进行系统稳定性测...     

基于HHT的煤岩破裂微震信号分析

微震信号处理是目前研究微震监测技术应用领域中的一个重要课题,应用ESG微震监测系统采集煤巷炮掘过程中产生的煤岩破裂微震信号,针对所采集微震信号具有明显的持续时间短、突变快等特点,选用希尔伯特黄变换(HHT)对其进行处理。HHT包括EMD分解和Hillert变换两部分,微震信号经过EMD自适应分解得出9个IMF分量和一个残余分量,对各IMF分量进行Hillert变换做出Hillert谱,从Hillert谱中得出煤岩破裂微震信号频率响应主要集中在500-800Hz,用边际能量谱加以验证得出Hillert谱在应用中的准确性,为进一步认识煤岩破裂的机理和预测煤岩动力灾害提供了有效的技术途径。     

煤矿生产系统干扰事件的离散小波变换检测

小波变换常用于数字信号传输的噪声检测与处理,为了检测煤矿生产系统中的突发事件,将其模拟为数字信号传输中的干扰,构建系统稳态方程和对应的扰动方程,根据离散小波变换原理,将煤矿生产系统中的监测数据分解为近似部分和细节部分,再进行离散变换。采用多尺度边缘检测法,由光滑后的一阶和二阶导数检测出信号的模极大值点即为瞬态突变点。将A矿记录到的瓦斯浓度监控数据进行可行性分析后,在MATLAB的wavelet工具中对该瓦斯浓度监控数据作离散小波变换,找到四个瓦斯浓度瞬态突变点,那么这四个时刻发生了煤与瓦斯突出事件。结果表明该方法简单、实用性强。据此从计算机实时监控和现场技术防突方面提出应对煤矿干扰事件的措施。     

大落差输油管道局部高点水击压力预测方程研究

为预测大落差管道局部高点水击压力,避免在关阀、停泵等应急操作过程中因高点低压而使油品气化,采用OLGA软件水击计算模块分析介质流速、高点稳态压力、关阀时间、阀门位置对高点水击压力的影响机制,并结合国内某原油管道现场SCADA系统数据进行验证;采用通用全局优化算法(UGO)和列文伯格-马夸尔特法(LM)建立局部高点压力预测方程,相对误差在5%以内。研究结果表明：本文方程可实现大落差输油管道水击过程中局部高点水击压力的预测。研究结果可为大落差输油管道安全运行与管理提供参考。     

老虎台矿55002#掘进面通过F7-1断层前后微震事件的时空特征分析

冲击地压作为一种特殊的矿压显现形式,对抚顺矿业集团老虎台矿深部开采的安全生产造成了严重的影响,在该矿的实际生产中,地质条件是引发冲击地压发生的重要因素。鉴于微震监测系统是目前在煤矿井下监测冲击地压应用较为广泛的手段之一,本文利用波兰ARAM IS/MA微震监测系统对老虎台矿55002掘进工作面通过F7-1断层前后的微震特征信号进行连续观测,分别从时间和空间上研究此掘进面通过断层前后的微震特征,验证了一种典型的冲击地压发生时间前后的微震活动规律,并结合实际地质条件从位置上分析了微震事件与断层等地质构造之间的关系,进而根据空间分析结果圈定了重点防治冲击地压区域,使老虎台矿在该工作面掘进生产中提前采取相应的防范措施,顺利通过断层等地质构造异常区域,确保了安全生产。     

基于LabVIEW的水质微型站实时故障诊断专家系统

设计一种基于微试剂原位水质检测仪的多参数水质微型站监控系统。通过对水质检测流程合理分析以及各监控点反馈信号诊断,结合LabVIEW可视化编程技术、信号分析技术和测控技术,分别从硬件和软件方面,设计了一种基于多传感器数据融合的水质微型站监控感知的检测流程测控模型。现场应用结果表明,采用诊断专家系统的水质微型站监控系统满足水质测控的需求,极大提升系统的稳定性、安全性。     

Sizing pressure relief valves in flashing and two-phase service: an alternative procedure

In view of the greater accuracy of the ω HEM correlation and the resulting conservative PR valve sizing (relative to the traditional PR valve sizing methods), the ω HEM-based flow calculations are recommended for all situations where flashing or two-phase flow occurs within the PR valve. However, as with any correlation, the accuracy of the ω HEM correlation results drops as the system to which it is applied diverges from the data used to develop it. Analysis of 15 different systems representative of actual refinery streams indicate that for fluids with a wide boiling range and for very non-ideal systems such as those containing hydrogen, the HEM correlation underpredicts the mass flux significantly (i.e. overpredicts the PR valve size). Since the large deviations are on the conservative side, the procedure will result in excessively large PR valves that may cause problems because of chattering of the PR valves, but would not present potential for vessel failure. The majority of the deviations are a result of the fact that the simplifying assumptions built into the correlation for single component do not truly characterize the actual flashing behaviour of many multicomponent fluids. The alternative approach presented, in which the correlation parameter ω is based on the actual flashing behaviour, eliminates nearly all the deviations and significantly improves the results of the correlation regardless of the system analysed. For trouble systems (those containing more than 0.1 wt% hydrogen and for some multicomponent fluids with a nominal boiling range greater than 80°C (150°F), the alternative approach should be used to define the correlation parameter ω. Use of this alternative approach is valid for any system (and will improve the accuracy of the correlation) but does require an additional flash calculation. However, for other systems the original formulation of ω is adequate and can be used.     

电力变压器无线温度监测系统的研究

我国变配电用变压器数量众多、分布广泛,充分利用现有的无线电通讯技术、以太网等监测技术、可以构建一个安全可靠的变压器无线温度监测网。本文介绍了在配电变压器上安装无线温度监测系统,通过实时监测变压器的温度变化情况,及时发现变压器存在的缺陷或发生故障的位置,并通过中短距离无线网络转发方式,将信号传递至以太网,彻底解决现场监测配电变压器参数的困难,从而实现变压器数据的实时采集和传输,实现区域内乃至全国性的变配电变压器信息的汇集与监测体系。     

海洋平台振动监测技术试验研究

为保证海洋平台服役期间安全运行,以实验室海洋平台模型为研究对象,开展有关振动监测技术的试验研究。通过预制损伤等物理手段,模拟海洋平台模型完好与损伤状态。使用加载设备对平台模型加载,采集其在不同加载角度、频率与增益下的动力响应。对振动传感器校准后,利用传感器、信号调理仪以及信号采集软硬件设备,组成监测系统。分析试验数据,调整相关试验参数,选取最佳信号采集状态。选取双谱分析法对试验数据进行信号处理,得出平台模型完好与损伤状态的数据变化。结果表明:根据振动监测数据的双谱模量与频率分布,能够识别损伤。     

残矿回采地压安全预警系统的构建方法与应用研究

为提高矿山的安全生产水平,针对地下矿山复杂环境下残矿回采过程潜在的安全问题,并基于安全系统工程的观点与粗糙集理论的属性约简功能,提出残矿回采地压安全预警系统的构成内容与构建流程,建立地压监测数据的神经网络灰色Verhulst算法组合预测模型和安全评价模型。据此,构建国内某矿山残矿回采中段的地压安全预警系统,该地压安全预警系统为本矿山的残矿回采过程提供了安全保障。残矿回采地压安全预警系统能指导矿山循序渐进的构建符合残采系统工程实际的安全预警系统。     

基于马尔可夫的地面控制井下安全阀可靠性评估

为保障地面控制井下安全阀系统的安全运行，防止系统发生故障，建立了井下安全阀可修复系统的马尔可夫模型；针对系统设备构成复杂及共因故障等问题，基于β因子模型描述共因失效，同时将模型划分为3个独立模块，通过克罗内克积方法合并，评估系统可靠性；参照OREDA可靠性数据，定量求解井下安全阀系统可用度、可靠度以及稳态指标，研究模型中状态转移概率对系统稳态可用度的影响。研究结果表明:井下安全阀系统的可用度随时间增长而迅速到达稳态值；系统检修周期应小于2.5 a；根据可靠性分析结果，运营方应考虑系统经济与可靠性间的博弈关系，合理优化系统冗余结构与维修周期管理，防止井下安全阀系统失效。     

The influence of safety at work on safety at home and during leisure time

It has been argued that the effects of safety programmes extend to safety related behaviour outside the work environment. Data from studies of the behaviour of workers in three industries with a high focus on safety were examined in order to explore this argument. By means of data collected through a questionnaire, safe behaviour and emergency preparedness behaviour at home and during leisure time were measured in a case-control study. The findings indicate that workers in two of the three studies did not transfer safe behaviour from workplaces with a high focus on safety to home and leisure arenas. The safety consciousness acquired by workers at their workplaces in the absence of specially designed home and leisure time intervention projects seems to be insufficiently comprehensive or deep enough to influence safe behaviour in other arenas. While safe behaviour was not transferred, the emergency preparedness behaviour was. This indicates that the contextual and situational aspects of emergency preparedness are shared across risk arenas.     

Leadership and employees’ perceived safety behaviours in a nuclear power plant: A structural equation model

Leadership is considered an essential element in guaranteeing the safe running of organizations. The purpose of the present study is to find out how leader behaviours influence employees’ safety behaviours (perceived safety behaviours) in the nuclear field. In an attempt to answer this question, the authors of this research have considered the way this influence is exercised, taking into consideration some important factors like safety culture and safety climate. To achieve this, the empowerment leadership model, based on a behavioural approach to leadership, was used. The sample was made up of 566 employees from a Spanish nuclear power plant. The results indicated that when safety culture was strong, leader behaviour generated a higher safety climate among the members, which predicted their perceived safety behaviours. Support was found for a structural model linking leadership and safety behaviour to safety culture and safety climate. The implications of these findings for the theory of safety and the way they can be put into practice are outlined.     

电感性本质安全电路L/R的选择原则

基于电感性本质安全电路放电电流线性衰减模型,引入最小建弧电压的概念,得到了放电时间不含未知参数的表达式,利用电感电路的本质安全性能判别式,确定了电感电阻比L/R的选取原则.     

基于无线传感器网络的市政下水道可燃气体监测系统设计及应用

为防止下水道可燃气体积聚引发爆炸事故,利用无线传感器网络技术设计了市政下水道可燃气体监测系统.实测结果表明:气体传感器监测数据相对误差在2.0%以内,无线数据收发设备的年发送成功率达到98.0%,满足工程运用需求,系统具有较高的可靠性和稳定性.结合无线网络覆盖范围广、实时在线的特点,该系统实现了对不同区域下水道内可燃气体浓度的远程监测,为下水道的安全预警提供了有效依据.