局部投影降噪在往复压缩机故障诊断中的应用

往复压缩机的振动信号为典型的非线性、非平稳信号.提出利用局部投影法对振动信号降噪,提取关联维数,并与热力参数相结合诊断往复压缩机故障的方法.首先利用基于定量递归分析的局部投影降噪算法滤除振动信号中的噪声,然后提取关联维数,再根据热力参数计算气缸的压缩比,最后结合关联维数和压缩比,诊断压缩机的故障.结果表明:应用局部投影法降噪后振动信号的局部标度指数曲线存在明显的平台区,关联维数易收敛;在降噪后时域指标无明显变化的情况下,关联维数变化明显,基于局部投影法降噪后的关联维数更能有效地反映设备的故障状态变化.实例中诊断出的往复压缩机活塞磨损故障验证了这种方法的有效性.     

浅谈往复式压缩机振动原理及管路支架改进

本文从振动的基本原理着手,对往复式压缩机管路振动分析,总结出控制往复式压缩机管路振动的措施。     

基于混沌理论的往复式压缩机故障诊断

实测某往复压缩机气缸在正常、活塞体松动及拉缸工况下的振动信号,计算信号的关联维数、Kolmogorov熵及最大Lyapunov指数,并证明信号具有非线性。用奇异值分解(SVD)降噪法对信号进行降噪,通过奇异熵增量曲线选择降噪阶次,用互信息法求最佳延时,并用假近邻域法求最佳嵌入维数,同时用G-P算法、小数据量法求出关联维数、Kolmogorov熵及最大Lyapunov指数。计算结果表明,3种工况下的往复压缩机气缸振动信号均为非线性混沌信号,故障越严重,信号表现出的混沌特性越明显,可依据混沌指标对往复压缩机气缸的状态进行监测。     

往复式压缩机的电子计算机模拟和机理设计

本文介绍往复式压缩机电子计算机模拟和机理设计的发展情况,并从往复式压缩机的工作过程的描述入手,将机理设计的数学模型和常规设计的计算公式比较,论证了两者既有联系又有差别的关系,指出从经验或半经验设计向机理设计发展和过渡是往复式压缩机设计的发展趋势。     

往复式活塞氮氢气压缩机故障及排除

往复式压缩机是化工企业中非常重要的机械设备,往复式活塞氮氢气压缩机在现代化工企业中应用十分广泛,在企业生产中发挥着重要的作用。压缩机发生故障会造成生产效率的降低或者停产,甚至造成火灾或者其他安全事故,造成巨大的经济损失。该文对往复式活塞氮氢气压缩机的常见故障进行分析,并提出故障排除的方法,旨在保证生产的顺利进行,提高生产效率。     

往复式压缩机管道振动原因与减振措施

随着经济的发展和社会的进步,往复式压缩机在化工行业中的应用越来越广泛。往复式压缩机管道振动是常见的故障之一,通过理论分析和计算较详细地分析了压缩机管道振动的原因,并采取了较为有效的减振措施。     

浅谈往复式6M45压缩机气阀故障诊断及维修

往复式压缩机是根据工作时所需要压力的高低来工作,它可以分为单级是多级。并且为了使机器受载均衡,可以分为单列或是多列。在化工生产中往复式压缩机可以提高压力和输送介质的动力源,并且工作介质相当广泛。因此本章对往复式6M45压缩机气阀故障诊断进行了解和划分,并分析维修方案。     

TA-80型往复式空气压缩机结构动态特性分析

从数值和试验两方面对TA-80型往复式空气压缩机进行了模态分析。采用有限元软件ANSYS中MPC装配技术实现了压缩机的储气罐与曲轴箱及电机间的螺栓连接装配关系,并引入压缩机与刚性平面接触来模拟压缩机与地面的单边约束问题。研究结果表明数值计算结果与试验结果吻合较好,从而验证了有限元计算模型的正确性,所得结果可用于该型号往复式空气压缩机的故障诊断分析。     

往复式压缩机故障信息模糊二元树诊断方法研究

结合图论理论和局域波理论,提出了一种基于模糊图的往复式压缩机故障诊断方法.首先将往复式压缩机故障信号进行局域波时频处理,根据系统的故障状态-特征表,找出最大故障信息量特征群.基于图论理论建立最大故障信息量模糊图,通过对模糊图的分析,找出可以进行匹配的路径信息量最大的部件.该方法应用于某往复式压缩机故障诊断中,具有一定的工程实用性.     

二氧化碳往复式压缩机故障诊断及检修方法

本文以在役二氧化碳往复式压缩机为例,简单介绍了往复式压缩机在气、振动和噪声、密封泄漏、油压系统、排气温度和管道振动等六个方面常见故障进行了详细的分析,并针对故障的原因提出处理方法。     

Fault Diagnosis of Reciprocating Compressors Valve Based on Cyclostationary Method

The relationship between second-order cyclostationary method and time-frequency distribution is studied,and cyclic autocorrelation(CA) function is indicated to be one sort of special time-frequency distribution method.Furthermore,a fault diagnosis method for reciprocating compressors based on empirical mode decomposition (EMD) and CA function is proposed,and then it is applied to the fault diagnosis of reciprocating compressor valve.Firstly,the vibration signal of reciprocating compressor valve is decomposed by using EMD method,and several intrinsic mode functions (IMFs) are obtained.Secondly,the IMFs are evaluated by some denoising criterions to remove the noise and interfering ones.Finally,the CA functions of the remained IMFs are calculated,which will be used to reconstruct the CA function of the original vibration signal.Engineering application indicates that this method can sufficiently inhibit the cross-interference items of CA function.Therefore,more explicit working conditions of reciprocating compressor components can be achieved.     

Research on fault diagnosis method of piston rod based on harmonic wavelet and manifold learning

As the core part of reciprocating compressor,piston rod is easy to cause a serious accident when abrasion and breakage fault occur to it. Therefore,it is very important to monitor its running state. At present,a small number of reciprocating compressors have been installed on-line monitoring and diagnosis system,most of which can only monitor a single vertical subsidence of piston rod and it can't fully represent the running state of piston rod. Therefore,a method of monitoring the vertical and horizontal displacement of piston rod axis orbit is simultaneously used. In view of the characteristics that the piston rod axis orbit is disordered and difficult to extract features,purification of the axis orbit is carried out based on harmonic wavelet and then features are extracted such as vibration energy,natural frequency and the axis orbit envelope area. After that,a nonlinear local tangent space manifold learning algorithm is used to reduce the dimension of the features and obtain sensitive features. By analyzing the practical cases,the effectiveness of the method for fault monitoring and diagnosis of reciprocating compressor piston rod assembly has been verified. Finally,as BP neural network has the characteristics of solving complex nonlinear problems,the validity of the fault diagnosis method of reciprocating compressor piston rod based on harmonic wavelet and manifold learning is proved by actual case data analysis based on BP neural network.     

基于时频图像GLCM-HOG特征的往复压缩机故障诊断

往复压缩机的故障诊断技术能够为工业生产提供有效保障,针对传统方法诊断准确率不高的问题,提出了一种基于振动信号时频图像灰度共生矩阵-方向梯度直方图(GLCM-HOG)特征融合的往复压缩机故障诊断方法.首先,采用小波变换的方法处理往复压缩机的振动信号,生成时频图像;其次,利用灰度共生矩阵(GLCM)和方向梯度直方图(HOG)的方法提取时频图像特征,融合构建GLCM-HOG特征;最后,将融合特征输入支持向量机(SVM)进行分类,以判别往复压缩机的运行状态.实验结果表明,所提方法对设备的状态识别准确率可以达到92.33％,能够实现往复压缩机的准确诊断.     

A fault diagnosis method of reciprocating compressor based on sensitive feature evaluation and artificial neural network

A method combining information entropy and radial basis function network is proposed for fault automatic diagnosis of reciprocating compressors.Aiming at the current situation that the accuracy rate of reciprocating compressor fault diagnosis which depends on manual work in engineering is very low,we apply information entropy evaluation to select the sensitive features and make clear the corresponding relationship of characteristic parameters and failures.This method could reduce the feature dimension.Then,a complete fault diagnosis architecture has been built combining with radial basis function network which has the fast and efficient characteristics.According to the test results using experimental and engineering data,it is observed that the proposed fault diagnosis method improves the accuracy of fault automatic diagnosis effectively and it could improve the practicability of the monitoring system.     

往复式压缩机气阀阀片的动态气体力的测定方法和实验装置

本文提出了一种测量和计算往复式压缩机气阀阀片所受动态气体力的方法,首次在运转的往复式压缩机上测得了阀片所受动态气体力。还介绍了实验用气阀的设计、实验装置和有关的实验测试技术。     

局域波法和高阶统计量在压缩机气阀状态监测中应用

为解决传统信号处理方法分析非平稳时变信号的不足,提出了一种适用于往复式压缩机气阀状态特征提取的新方法.首先使用局域波法将实测信号分解为多个基本模式分量,经过希尔伯特变换得到各分量的时频谱;然后计算归一化后幅值信号的高阶统计量,这些统计量很好地反映了气阀的劣化过程.通过对现场工作的聚乙烯二次压缩机组合阀振动信号的分析,验证了该方法在往复压缩机状态监测中的有效性和实用性.     

往复式压缩机出口管线振动的分析与改造

某厂220×104t/a加氢处理装置在实际生产中发现加氢精制装置高分压力控制不稳,引起往复式压缩机出口管线振动。本文首先对往复式压缩机出口管线振动的原因进行分析,得出压力脉动为主要因素。然后,通过对管系的重要区段进行改造,将往复式压缩机采用的Ⅰ回Ⅰ,Ⅱ回Ⅱ的控制方案改为Ⅱ回Ⅰ的控制方案。并对改造前后的方案分别采用DDC控制系统进行动态模拟实验,得到高分压力随时间变化的关系图,并进行压力不均匀度计算。最后,对比二种方案高分压力随时间变化的关系图以及压力不均匀度,得出Ⅱ回Ⅰ的控制方案比Ⅰ回Ⅰ,Ⅱ回Ⅱ控制方案大大降低管线振动,使压力控制平稳。     

Research on gas leakage through suction valves of reciprocating compressor under varying load conditions

A research concerning the coupling conditions of gas leakage through suction valves and capacity regulation is performed in an industrial reciprocating compressor.Both internal flow and thermodynamic characteristic are discussed in detail.The results show that the capacity of compressor can be regulated steplessly by controlling suction valve closure moment.And then the quantitative relationship between the capacity load and the closing angle of suction valve is revealed.The capacity load and valve leakage rate show obvious different features in P-V diagrams,which makes it easier to define appropriate features for detecting cracked or broken reciprocating compressor valves under varying load conditions.A set of curves of compression work and discharge gas mass are obtained and a method for rating thermal performance of a compressor is presented using these curves.