One of the most important assemblies of electric rolling stock is a wheel-motor unit. Its faultless operation determines abilities of transport to fulfill their main functions.
One of the main requirements to the wheel-motor units is a set operational resource. Operation of rolling and sliding friction systems, such as ball- and roller-bearing assemblies, traction gears, commutator-and-brush device and other devices, which are the elements limiting the train resource in general, and depend on the vibration condition, quality of manufacture, repair and assembly.
It is reasonable to carry out the diagnostics of these facilities both during operation and maintenance with the required diagnostic depth.
Typical for these malfunctions is high level of noise, vibration, impact sound. By the deviations and higher levels of these parameters with the help of vibration analysis means it is possible to trace the defect development up to the moment when the usage of defected element is inexpedient or impossible in terms of operation.
Vibration analysis is based on the analysis of vibration process features changes, presupposing that the vibration signal of the operation unit contains all the information on the interactions of its details.
Basakin V.V. Analysis of malfunctions of wheel-motor units of motor-driven rolling stock for the purpose of their diagnostics // Nauka, obrazovanie, biznes (Science, education, business). - 2012. - pp. 136-140
The main purpose of condition monitoring systems (health monitoring systems) of piston compressors is maintenance of their safe and accident-free operation. The majority of modern piston compressor monitoring systems use direct measurement of structural parameters and thermodynamic process parameters. The quantity of structural parameters that can be measured by means of the sensors installed into assemblies does not guarantee sufficient control of technical condition of compressor assemblies and parts.
Measurement of compressor's thermodynamic parameters is an effective method of compressor's condition control in case the compressor squeezes technologically stable gases. Otherwise thermodynamic parameters mostly characterize technological working conditions of a compressor and not its technical condition.
The most effective monitoring covers condition of assemblies and details that are subject to frequent repairs. It should be noted that such assemblies and details determine safe exploitation of a compressor.
In order to reduce the cost of monitoring system's purchase and maintenance it is reasonable to measure the parameters of indirect processes, for example, vibration. Vibration sensors are easy to operate because they are mounted directly on a case of a compressor and its assemblies.
The paper presents data about repairs and faults of piston compressors at different oil-refining plants. On the basis of statistical data processing the most vulnerable assemblies and frequent faults are detected. In addition repair cost of a compressor is estimated. On the basis of the data obtained through processing the location of sensors to diagnose compressor assemblies and to detect defects by vibration parameters was detected.
The paper contains a block diagram of monitoring system of piston compressors based on a real-time condition monitoring system COMPACS® that has been functioning at oil-refining plants. Trends and parameters of vibration acoustic signals indicating emergence and development of compressor defects and malfunctions were analyzed. Emergence and development of defects and malfunctions in a compressor were illustrated by the analysis of trends and parameters of vibration acoustic signals. The analysis of data of COMPACS® monitoring system confirms high efficiency of compressor health monitoring systems that use vibratory (vibration acoustic) signals analysis.
Kostyukov V. N., Naumenko A.P. Choice of reciprocating compressors units for real time health monitoring // Condition Monitoring and Diagnostic Engineering Management (COMADEM-2011), pp. 824-833
Low objectiveness of condition assessment and lack of observability of hidden processes of condition degradation of potentially dangerous and critically important units, caused by the wear and inadequate actions of maintenance and repair personnel. These are the fundamental reasons of operational problems of the units.
Operational losses can be minimized by timely and purposeful maintenance on the basis of real-time condition monitoring results and usage of full resource of the units, eliminating unscheduled (emergency) shutdowns and repairs providing high level of safety and technical readiness.
The existing regulatory framework of international standards determines only the general approaches to the monitoring problem solving by measuring of parameters of different processes, including vibration measurement.
Joint usage of various methods of diagnostics and non-destructive testing for condition control of potentially dangerous and critically important units, on one hand, is a complicated and actual task, since it is necessary to develop a complex of diagnostic features based on various parameters of physical processes. On the other hand, various types of units demand specific decisions on choosing of the diagnostic methods and parameters.
The solution of this problem can be made on the basis of fundamental research works, adequate approbation of the decisions and the developed systems operation in real conditions of potentially dangerous and critically important units functioning.
Many years of DYNAMICS SPC experience in design, implementation and operation of real-time monitoring systems for dangerous production facilities without shutdown, demounting and decommissioning at Russian enterprises and abroad allowed to develop not only methodological bases and brand-new technological decisions and means of real-time condition monitoring, but, also, regulative-and-methodical documents, which determine the classification and main technical requirements to monitoring systems, operational norms of vibration for several types of machines and mechanisms, and principles of dangerous production facilities monitoring.
Kostyukov V. N., Naumenko A.P. Experience of monitoring systems design and operation // Monitoring – Nauka i bezopasnost’ (Monitoring - Science and Safety). - 2012. - pp.108-119
In the basis of diagnostics and monitoring of piston machines lies collection and processing of the data providing detection of defects and malfunctions of piston machines with a set depth of specification and reliability, as well as the danger rates.
Diagnostics and monitoring technology realization is based on the structure models of vibro-acoustic signals occurring if case of failure nucleation in assemblies and details of piston machines, combination of their diagnostic features (DF) of malfunctions and signal parameters (DPF) if case of failure nucleation, standard values of DF and DPF, vibro-acoustic signal transduction and vibro-acoustic signal parameter assessment.
One practical method of the technology realization and diagnostic and piston machines monitoring problems solution is implementation of the mentioned above methodological decisions which determine the knowledge base connecting DPF and condition of assemblies and details of piston machines into the algorithms of the COMPACS® diagnostic and monitoring system functioning.
The article deals with the principles of formation of the technology for diagnosing by vibroacoustic signal parameters and condition monitoring of piston machines. The methodology of diagnostic signal processing and the operating diagram of the system for technical diagnosing are considered. Particular attention has been paid to the structure and principle of operation of decision-making expert system.
Kostyukov V.N., Naumenko A.P. Basic principles of diagnostics and monitoring of piston machines // Bulletin of the Siberian office of Academy of Military Sciences. - 2011. - pp. 198-201
With the help of automatic systems for real-time diagnostics and monitoring COMPACS®, which cover a huge amount of machinery equipment on the dozens of Russian enterprises, wide-ranging researches were carried out. As the result, the database in the form of vibration parameter trends was created in order to discover connection patterns between the vibration parameter changes nature and condition degradation of units of different types.
There is an experimentally proved mathematic model of the vibration parameter trend, which confirms the exponential increase of the trend in a catastrophic wear state. The statistical features of vibration parameter trends are examined. It is ascertained that the values of vibration parameters and their growth rates with high reliability are subjected to the Weibull-Gnedenko law.
Classification of the vibration parameter trend and other diagnostic features measured by the real-time monitoring systems is conducted. It revealed the trends with slow, medium and fast growth rates, trends with monotonous, exponential, alternating and multimodal features. There are also trends characterized by high and low dispersion.
All the types of trends reflect different types of the developing faults and their danger level. This data allowed to evaluate the standards of vibration parameter s and their growth rates in the centrifugal pump-and-compressor units. The received results are the basis of several Russian Federal standards, concerning condition monitoring of hazardous production facilities.
Kostyukov V.N., Kostyukov A.V. Vibration parameter trend classification for the aims of real-time condition monitoring // Testing. Diagnostics. - 2011. - № 12. - pp.26-33
In order to provide stable, uninterruptible process of power production, one needs the constant condition control of the electric stations equipment. However, mainly, the general electric mechanisms - turbines – are equipped with the operational control and blocking systems. At the same time for the ensuring of a turbine operation it is necessary to use a few dozens of auxiliary equipment such as: different grinders, blowing fans, smoke-exhausters, feed, condensate, circulating, net pumps, coolers. Though, many auxiliary units are operated with no reserve and their sudden failure leads to the reduction of the amount of produced energy right up to full shutdown of the turbine.
Sudden failures are determined by the lack of constant automatic condition monitoring and diagnostics of auxiliary equipment. Usually, the vibration-diagnosing staff, which controls the equipment of thermoelectric power station by means of portable instruments, counts 2-3 members, and the number of the power station units is about several hundreds. In connection with that, the interval of the "manual" diagnostics of units exceeds the failure nucleation period, which leads to the sudden (from the operational personnel point of view) failure and faults of main units operation.
Equipping the auxiliary units of the power stations with systems of automatic diagnostics and condition monitoring COMPACS® is a real way to provide safe and reliable operation of electric stations.
The COMPACS® system ensures reliable diagnostics of the bearing defects, lubrication defects, technological process violations (cavitation, hydro-blows, etc.), defects of shaft centering and rotating parts balancing, poor fastening of pumps and electric motors, electro-magnetic defects, face seal failures more than 70% of which are caused by the high vibration rates of pumps and electric motors.
Kostyukov V.N., Tarasov E.V. Condition Monitoring and Automatic Diagnostics of the auxiliary equipment of the typical electric stations // Problems of vibration, vibration adjustment, vibration monitoring and diagnostics of the equipment of power plants. - 2011. - pp. 24-28
Low objectiveness of condition assessment and lack of observability of hidden processes of production facilities condition degradation, caused by the wear and inadequate action of the service and maintenance personnel are the fundamental reasons of troubles in hazardous production facilities operation. The operational losses can be reduced to the minimum by carrying out timely and purposeful maintenance based on the real-time condition monitoring results, using the full resource of the equipment, eliminate its unscheduled (emergency) shutdowns and unplanned repairs, providing high safety level and technical readiness coefficient.
The present regulatory base in the form of international standards determines only common approaches to solving the problems of monitoring, both with vibration measurement and different process parameters measurement.
The combined usage of various methods of diagnostics and non-destructive testing for condition control, on one hand, is a vital and complicated problem, due to a need to develop a complex of diagnostic parameters, based on parameters of various physical processes. On the other hand, each type of units requires particular method selection in terms of diagnostics and diagnostic parameters.
The solution of this problem can be found by means of fundamental research-and-development works, adequate testing of the offered solutions and operational practice of the developed systems in real conditions of functioning at operating plants.
Kostyukov V.N., Naumenko A.P., Boychenko S.N., Kostyukov A.V. State and perspective of development of real-time condition monitoring of production facilities // Problems of vibration, vibration adjustment, vibration monitoring and diagnostics of the equipment of power plants. - 2011. - pp. 29-34
Many years of researches in the field of condition monitoring and diagnostics of piston compressors have allowed to realize modern methodology and achievements in the field of piston machines condition monitoring and diagnostics, which allows to carry out automatic real-time monitoring and diagnostics on the basis of multivariate processing of the diagnostic signals and algorithms of automatic functioning of the expert decision support system:
real-time monitoring and diagnostics methodology is based on the measurement of the indirect processes’ parameters(acoustic vibrations), which requires not more than 5 sensors per cylinder, measurement of direct structural and thermodynamic parameters are also available;
algorithms of the real-time decision-making expert system with an automatic identification (diagnosing in a speed rates of diagnostic signals measurement) of more than 23 malfunctions of piston compressor assemblies and their danger rates, and also issuing of purposeful prescriptions to the personnel in order to conduct compensating actions;
scientifically grounded period of diagnosing allows to get static and dynamic errors of identification of less than 5% rate, which makes possible to carry out condition monitoring of critical equipment of the first class and other classes, as well as a production facility in general;
the COMPACS® real-time monitoring system has a distributed parallel-serial structure, requires much less amount of sensors and cable, and, consequently, less installation and maintenance costs, provides low cost of ownership and switches piston compressor operation to the condition-monitored one, ensuring high economic efficiency of implementation..
Kostyukov V.N., Naumenko А.P. Systems for real-time automatic condition monitoring and diagnostics of piston compressors // Mashinostroyenie i tekhnosfera XXI veka (Mechanical Engineering and Technosphere of the XXI Century). - 2011. - pp.91-99
A bearing is a main element, influencing work capacity of any machinery unit, since the reliability of the bearing sets a limit on the unit operation life.
The usage of the diagnostic means of machinery condition at all stages of its life: fabrication, mounting, operation, repair, allows timely detection of errors, elements of a low quality, elements which condition is critical or near critical, and to take proper measures in order to increase the reliability of the machinery.
The article dwells upon the issues of the diagnostics of the machinery, rolling bearings directly in operation.
Kostyukov V.N., Tarasov E.V. The research on the vibration-acoustic features of rolling bearings of high-voltage electric motors in operation // Glavniy Energetic (Chief power engineer). - 2011. - №8. - pp. 65-68
Observability of the machinery degradation process in real time allows to eliminate emergency repairs and carry out the scheduled condition-monitored repairs only, which ensures total elimination of emergencies.
Resource-saving is not only the reduction of material resources consumption, but, also, the reduction of labour and financial resources expenditures on elimination of accidents consequences, machinery break-downs and downtime losses. The real growth of the units’ run-to-failure period up to 2-5 years, which nowadays all companies demands from the plants, is impossible without implementation of the COMPACS® monitoring systems – basic element of safe resource-saving operation of petrochemical plants and refineries.
Highly reliable diagnostics can be proved each time after the shutdown and decommissioning of a unit by a personnel due to the system warning. This is a source of emergencies and losses elimination, the increase of run-to-failure time, with the usage of the full machinery resource, decrease of all kinds of expenses, substantial speeding-up of the commissioning process.
At the same time, the COMPACS® systems structure allows to configure its software and hardware easily in order to conduct monitoring of the different kind of the equipment – centrifugal, console and double-seat pumps, air- and gas-blowers, fans and air-cooling devices, centrifugal and piston compressors, etc.
Kostyukov V.N., Kostyukov A.V. Innovative systems of vibration-acoustic monitoring of the machinery condition - COMPACS // Neftepererabotka i neftechimiya (Refining and Petrochemistry). - 2011. - №8. - pp. 3-11