膨胀机增压后冷却器泄漏处理措施

分析两起膨胀机增压后冷却器泄漏造成主体设备停运的故障,一起是由冷却器管道选材和冷却水处理不当引起,另一起是由制造质量不合格引起。介绍故障处理方法和从中获得的经验教训。     

热网系统故障诊断的探讨

热网故障给供热企业和居民都带来了很多麻烦,在系统正常运行状态下,系统允许泄漏量即系统允许补水量不应超过总循环水量的2%,否则视为系统泄漏故障。本文从几个方面论述了热网系统故障的诊断     

两起分子筛纯化系统阀门泄漏故障的分析与处理

介绍了两起分别由分子筛吸附器正流空气进口阀和再生气体出口阀泄漏引起的10000m~3/h空分设备分子筛纯化系统故障,阐述了具体的故障处理经过。     

分子筛纯化系统均压阀故障分析与在线修理

因为分子筛纯化系统均压阀泄漏,导致空压机的能耗增大。为降低故障处理的成本,采取在线修理,成功消除了泄漏故障。简述分子筛纯化系统均压阀发生泄漏的故障现象及原因分析过程,详细阐述在线修理的时间和方案以及处理效果。     

热网系统故障的排除及诊断

热网故障给供热企业和居民都带来了很多麻烦,在系统正常运行状态下,系统允许泄漏量即系统允许补水量不应超过总循环水量的2％。否则视为系统泄漏故障。系统泄漏主要是管道、阀门、散热器及其它设备破裂所致。系统的堵塞更加复杂,常因施工、运行不当,存留在管道中的砖、瓦、砂、石．灰、木、棉等堵塞系统。本文以热水供热系统为例从二个方面论述热水供热系统常见的故障及其排除方法,供大家参考。     

时频分析法在锅炉承压管线泄漏检测中的应用研究

准确检测锅炉承压管线泄漏是保障锅炉安全运行的关键技术,音频分析法是检测承压管线泄漏故障的主要手段,提出一种基于联合时频分析(Joint Time-Frequency Analysis, JTFA)研究锅炉背景声和承压管线泄漏声的时频特征,判定泄漏故障的方法。设计了由前置放大、程控滤波、增益补偿处理的双通道音频信号采集电路;采用快速傅里叶变换获取信号广义谱特征,采用程控滤波对采集信号加动态频率窗,再采用短时傅里叶变换对采集信号时间加窗,多角度分析信号的时频特征,以判定承压管线运行是否存在泄漏故障。相比于传统的RC滤波加快速傅里叶变换分析方法,这种动态加双窗的时频分析法能够提高泄漏信号采集的灵敏度和泄漏故障判定的准确性。     

RD-PCM管道防腐测试仪应用技术研究

泄漏是长输管道运行中的主要故障,通过对 RD-PCM 管道防腐测试仪的应用技术研究,较好地解决了输油管线的泄漏检测,能够及时监测泄漏故障和管线腐蚀程度,对于避免原油长时间泄漏、提高长输管道的现代化管理水平等有重要的意义,为企业挖潜降耗、保证安全生产提供了科学可靠的技术手段。     

制冷系统泄漏的原因分析与处理办法

制冷系统泄漏是空调制冷设备运行中较为常见的故障,一旦发生不仅会影响设备的正常使用,而且还可能造成压缩机的严重故障,从制冷系统的密封方式入手,分析了导致制冷系统密封失效的原因,以及不同工况下制冷系统泄漏的判断方法,在此基础上提出了一种处理制冷系统泄漏故障的作业方法及作业程序。     

电厂高压加热器泄漏主要原因及防范措施

加热器是发电厂的一种主要辅助设备,加热器发生故障,不仅影响发电厂的经济性,还常常直接威胁主机或其他设备的安全运行,甚至引起严重的设备损害事故,尤其是高压加热器管系泄漏等故障的频繁出现,仅次于锅炉爆管,而居于电厂故障的第二位．因此分析加热器泄漏原因,找出对策,尽可能减少泄漏具有十分重要的意义。     

高压断路器常见故障原因的分析与处理

通过对高压断路器拒分/合闸、误分/合闸、N2泄漏、液压机构压力异常以及液压机构漏油等故障的分析,指出了造成故障的原因并提出了相应的处理措施。对电力系统高压断路器故障的诊断和排除有很好的借鉴意义。     

一起空压机带水故障的处理

因级间冷却器泄漏,空压机带水而无法正常启动,在没有完全排除故障的情况下再次启动空压机,使空压机遭受了更大损伤。分析了冷却器泄漏的原因,阐述使空压机恢复正常运行工况的措施和平时操作中的预防措施。     

Performance investigation of a variable speed vapor compression system for fault detection and diagnosis

An experimental study has been performed to investigate the effect of four artificial faults on the performance of a variable speed vapor compression system. Experimental setup to test several artificial faults was made by modifying the conventional vapor compression test rig. Four major faults of compressor fault, condenser fault, evaporator fault, and refrigerant leakage, were implemented by observing the variation of cooling capacity. Two different rule-based modules for constant and variable speed operations were organized for an easy diagnosis of system faults. These two modules were applied differently as the cooling capacity satisfies the necessary air conditioning load. As a result, COP degradation due to the fault in a variable speed system is severer than that in a constant speed system.     

Decoupling features for diagnosis of reversing and check valve faults in heat pumps

Recently, a decoupling-based (DB) fault detection and diagnosis (FDD) method was developed for diagnosing multiple-simultaneous faults in air conditioners (AC) and was shown to have very good performance. The method relies on identifying diagnostic features that are decoupled (i.e., insensitive) to other faults and operating conditions. The current paper extends the DB FDD methodology to heat pumps. Heat pumps have all the same faults as occur for air conditioners with additional faults associated with components that accommodate heating mode, including reversing valve leakage and check valve leakage. Decoupling features were developed for these additional faults and laboratory evaluations were performed to evaluate diagnostic performance. It was found that check valve leakage could be detected and diagnosed before the heating capacity degradation reached 5% for a system with a fixed orifice expansion (FXO) device and 3% for the same system retrofit with a thermal expansion valve (TXV). Furthermore, the feature for check valve leakage is very insensitive to other faults and operating conditions. The decoupling feature for reversing valve leakage could successfully detect and diagnose faults for a TXV system before the heating capacity degraded 6% and was also insensitive to other faults and operating conditions. However, this feature did not work well for a system with an FXO in heating mode because the refrigerant exiting the evaporator and entering the reversing valve was typically a two-phase mixture. Fortunately, it was possible to diagnose this particular fault at many operating conditions in cooling mode for the system with an FXO.     

有限元漏磁仿真在异步电机非相邻断条故障检测中的应用

传统的电机电流特征分析(motor current signature analysis,MCSA)方法在进行异步电机转子非相邻断条故障诊断时容易出现误检。为此,提出一种基于漏磁检测的异步电机非相邻断条故障诊断方法。首先,在ANSYS@Maxwell-2D软件中对异步电机进行建模,针对电机健康、相邻断条、半极距断条以及全极距断条故障4种不同状态,在采样频率为10 kHz的条件下利用有限元法对电机进行漏磁分析,得出各状态的漏磁频谱。进一步,在相同条件下,利用实验测量得出异步电机定子电流频谱,并与相应的漏磁频谱进行对比。最后,通过频谱对比分析说明漏磁检测方法在异步电机转子非相邻断条故障诊断上的优越性。二维有限元分析与频谱对比分析结果表明:当异步电机转子断条间隔为半极距和全极距时,采用漏磁通频谱中的3sf_s和f_r+sf_s等特征信号可对故障进行有效识别;同时,在采用漏磁检测方法进行异步电机非相邻断条故障诊断时,f_r+sf_s谐波分量与电机负载水平关联性较小,相较于MCSA,漏磁检测方法的鲁棒性较高。所提方法可为异步电机其余电气故障的准确、鲁棒诊断提供参考。     

Fault detection in CMOS circuits by consumption measurement

Some testing problems in CMOS circuits are presented, including stuck-open and stuck-on faults, bridging faults, and excessive leakage in dynamic CMOS circuits. It is shown that the current consumption of a faulty CMOS circuit is several orders of magnitude greater than that of the fault-free circuit: hence, consumption measurement may be a suitable way of testing. Test by consumption measurement provides improved controllability and observability of some faults in comparison with the logic test     

Innovative thermoeconomic diagnosis of multiple faults in air conditioning units: Methodological improvements and increased reliability of results

Thermoeconomic faults diagnosis of air conditioning units is a pioneeristic approach to detect single or multiple faults and quantify their impact in terms of additional energy consumption. The poor reliability of conventional thermoeconomic approaches has been limiting the interest for practical applications of this technique. In this paper an improved thermoeconomic diagnosis is proposed and applied to a reference 120 kW_c air-cooled air conditioning system; a simulator is used to evaluate thermodynamic data under normal and faulty conditions. Four faults are individually or simultaneously imposed: fouling at condenser and evaporator, refrigerant undercharge and compressor valve leakage. For setting up the diagnostic tool only a few numerical or experimental tests are required; the results testify the procedure to be sufficiently reliable both when heavy or light faults are considered. Also, the performance of the diagnostic procedure slightly improves when the effects of “system level” faults like refrigerant undercharge are preliminarily filtered.     

电弧喷涂技术在转炉烟罩水冷壁防护上的应用

分析了转炉烟罩水冷壁的工况和漏水原因.根据其磨损、腐蚀、烧蚀、开裂等故障现象,应用电弧喷涂技术和适合的喷涂材料,先对烟罩水冷壁进行喷砂预处理,然后喷涂打底过渡层Al5Ni95 0.05～0.10 mm、工作涂层KBF3 0.20～0.40 mm,最后进行封孔处理.结果表明,在梅山炼钢厂转炉烟罩水冷壁表面喷涂保护涂层,减少了水冷壁表面的开裂、漏水,延长了其使用寿命.     

基于瞬时转速波动率的内燃机故障诊断方法研究

内燃机的瞬时转速包含着各个缸燃烧状态的重要信息,可以用于分析各个缸做功状态,诊断缸体点火相关故障,如燃料泄漏、气门泄漏和点火异常等故障。通过模型建立从理论上分析瞬时转速与气体压力扭矩、往复惯性力扭矩和阻力矩之间的关系,提出4个特征参数表征瞬时转速波动率波形及谐波特征,并通过仿真数据和实测故障数据证明瞬时转速波动率对于分析诊断内燃机点火故障的有效性,实现内燃机点火状态的早期预警。     

潜水电泵失效检测技术与方法

 按照潜水电泵80%～90%的失效或故障是由其机械密封和轴承的失效引起的实际情况,及潜水电泵其他故障的产生一般会引起电机电流增大的原理,提出通过检测机械密封和轴承是否失效、电流变化是否超标,来判断小型潜水电泵是否失效的检测方法。根据水泵机械密封主要是因端面过量磨损而产生泄漏,轴承则因润滑不良导致早期磨损而引起泵体振动的失效机理和特征,提出通过检测水泵密封腔的含水量和泵体振动加速度的大小来判别机械密封和轴承是否失效的方法和技术。研制开发了小型潜水电泵的失效检测系统,通过试验确定并验证了相应的失效判据。