Safety level at piston compressors units operation is determined by the reliability of their condition control, trustworthiness and timeliness of malfunctions and their causes detection. Today there are a lot of technical means which are developed and produced for monitoring and diagnostics of piston compressors and generally offered by the foreign companies. However, a question of adequacy of carried-out measurements to real conditions of piston compressors is opened.
The article reveals criteria of the equipment condition. As a rule, there are four categories of such conditions: "good", "acceptable", "measures required" and "unacceptable".
The article dwells upon the choice criteria of diagnostic signals for condition monitoring, gives the sources of a vibroacoustic signal.
The methodology and algorithms of piston compressors diagnosing are revealed. The distinctions between systems for real-time monitoring and on-line monitoring are listed.
Kostyukov V.N., Naumenko A.P. The modern methods and means of condition monitoring and diagnostics of piston compressors. Part 1 // Maintenance and Repair ("Tekhnicheskoye obsluzhivanie i remont"). - 2010. - №1. - p. 28-35
Revolutionary increase the repair quality of motor driven rolling stock (MDRS) and simultaneously reduce duration and laboriousness of obligatory after-repair control is possible by means of automatic systems for comprehensive diagnostics with automatic expert system of malfunctions detection, excluding subjective diagnose errors and providing reliable assessment of the most complex and critical systems of an EMU-train.
The article describes the system for comprehensive diagnostics of EMU-train sections COMPACS®-EXPRESS-TR3, which includes 7 sub-systems for the diagnosing of the most complex and damageable assemblies and units – wheel-motor units, isolation of high-voltage electric circuits, pantographs, compressed-air braking system control circuits, power and auxiliary electric circuits.
Due to the usage of the sub-system for electric circuits diagnostics, which is the part of the COMPACS®-EXPRESS-TR3 system, for the first time a possibility to detect details and devices, which condition leads to the decrease of a train productiveness and deterioration of operation conditions of electric machinery and a switchgear, to make the personnel’s work to be aimed at the liquidation of the particular defects, and not all the probable malfunctions, increase of the particular elements’ repair quality, reduction of the train after-repair control and checkout operations in more than 6 times.
The developed methodology of electric circuits diagnostics on the basis of the COMPACS®-EXPRESS-TR3 system allows to make EMU-train electrics checkout faster and easy during the commissioning with the help of prompt, timely and qualitative assessment of control, power and auxiliary electric circuits’ condition.
Sizov S.V., Aristov V.P., Kostyukov V.N., Kostyukov Al.V., Kazarin D.V. Automatic diagnostics of motor driven rolling stock electric circuits // Railway transport ("Zheleznodorozhny transport"). - 2010. - №5. - p. 56-58
Safe and resource-saving operation of machinery is provided by the machinery degradation process control, which allows to carry out all condition-monitored repairs of units, according to the schedule providing 100% exception of emergency repairs. Resource-saving is to be defined as not only reduction of material recourses, but reduction of labour and financial expenses of the enterprise on elimination the consequences of emergency, breakdowns, and losses caused by production shutdown.
The key component of calculations of condition monitoring system economic efficiency and conversion to safe recourse-saving production operation is an increase of the production length. Cost of the addition products not only covers costs of systems acquisition and provides their payback within several days, but also is the main source of increase of repair fund means which are aimed at providing longer non-stop work of the equipment and units of refineries.
The only means in Russia, really providing safe and resource-saving operation of the equipment, is diagnostic and monitoring systems - COMPACS®, successfully operating at many Russian enterprises for already more than 20 years. The systems implementation gives a real increase in the run-to-failure operation periods of units up to 2-5 years, and that is a modern requirement for plants.
Ionova Yu.B., Kostyukov V.N., Kostyukov An.V., Boychenko S.N. COMPACS monitoring systems // Scientific and technological center of the Council of chief mechanical engineers. - 2010. - p. 258-262
Machinery health monitoring – is supervision of its operation process changes in order to warn the personnel about unit reaching its critical state. It allows to make the most of the sudden failures gradual, due to their early detection and timely prevention.
Real-time monitoring – RT-Monitoring has a few essential differences from on-line/off-line monitoring. They consist in a strict regulation of an monitoring interval at the level of 10... 20% of an interval of the fastest development of malfunctions of the industrial complexes equipment.
That becomes possible on the basis of automatic systems with functionally uncertain structure, which does not depend on the equipment construction for the wide class of industrial complex units and contains a multilevel expert system. This allows to implement systems for real-time diagnostics and monitoring in case of prior uncertainty, when types of bearings, number of impeller blades, etc., can be unidentified, as well as to minimize static and dynamic errors and risk of failure omission.
The article dwells upon the main propositions of real-time health monitoring and the differences from on-line and off-line monitoring. There given rated correlations for certainty indexes and monitoring systems speed rate identification. The necessity of diagnostic features changes speed usage is shown. Definitions of monitoring, equipment condition danger, static error, dynamic error, zero-monitoring are given.
Kostyukov V.N., Kostyukov Al.V. Real-time Condition Monitoring of Equipment // Testing. Diagnostics. - 2010. - №3. - pp. 43-50
The article dwells upon the criteria of the equipment condition. The selection of diagnostic methodology and parameters, which not only detects condition but allows to carry out diagnostics with the required operation conditions and maintenance depth. Among the big variety of measured parameters the most informative are acoustic vibrations, which sources are cinematic pair impacts (piston-cylinder, pin-sleeve, etc.)
The sources of vibration acoustic signals of piston machines are given in the article:
Unbalance of the moving and rotating masses – inertial force of reciprocal moving masses, centrifugal force of inertia and the moments of the force.
Gasdynamic processes – pressure force of gases, gas flow during an admission and release.
Impacts and friction between elements and details of assemblies and mechanisms.
The methodology and algorithms of diagnosing of piston machines in real-time monitoring systems are described in the article. Also, the article gives the examples of a proper response of vibroacoustic signals’ various parameters to the condition changes of various piston compressor assemblies.
Kostyukov V.N., Naumenko A.P. Analysis of modern methods and means for piston compressors monitoring and diagnostics. Part 2. Real-time monitoring systems // NDT world. - 2010. - №2. - pp. 28-35
Repair quality in a depot can be influenced by an after-repair control, carried out either by dint of simple tools and devices or within debugging by means of an EMU train testing under a contact wire in several different operating modes. Such approach presupposes substantial time expenditures, which count up to 30 % of the whole processing cycle, and the results are subjective due to different levels of executors’ qualification and responsibilities.
To change dramatically the actual situation and to increase the repair quality of motor driven rolling stock (MDRS) within a simultaneous reduction of an obligatory control duration and labour intensity, one can use automatic systems for comprehensive monitoring.
Well-known developments in the field of railway transport health diagnostics possess a low degree of a unit control procedures automation within diagnostics and diagnosis-making and are focused on a locomotive rolling stock (electric and diesel locomotives), which does not allow to use these developments for EMU-trains electrical circuits diagnostics due to considerable structural and principal differences from MDRS.
The article contains the results of development and industrial application at “Russian Railways” JSC of the comprehensive system for EMU-trains sections diagnostics COMPACS®-EXPRESS-TR3, which provides an off-line automatic reliable and complete MDRS health monitoring in the depot conditions.
Kazarin D.V. Condition monitoring of electrical circuits in commuter trains // World of Transport. - 2010. - № 2. - pp. 60-63
The article considers a scheme, implemented in COMPACS® system for piston compressors real-time health monitoring. There are practical examples of different vibroacoustic signals parameters reaction to changes in the piston compressor units health. Peculiarities and efficiency of monitoring and diagnostic systems implementation have been described as well.
Kostyukov V.N., Naumenko A.P. Contemporary methods and means of piston compressors condition monitoring and diagnostics. Part 2 // Chief Power Engineer. - 2010. - № 12. - pp. 46-54
The article considers state and prospects of contemporary methods and means for piston compressors health monitoring and diagnostics at hazardous continuous production facilities. There is a review of health monitoring principles, implemented in all the known monitoring systems. The equipment health criteria are described as well. The authors have carried out the diagnostic features selection for monitoring purposes and described the vibroacoustic signal sources. Methodology and algorithms of piston compressors diagnostics are also included in the article.
Kostyukov V.N., Naumenko A.P. Contemporary methods and means of piston compressors condition monitoring and diagnostics. Part 1 // Chief Power Engineer. - 2010. - № 11. - pp. 40-50
Monitoring purposes for technical objects are: a timely detection of incipient malfunctions, an observation of their development up to a critical state and a timely personnel warning on malfunctions occurrence in order to develop measures aimed at ensuring a maximal duration of the unit operation and a timely fault-free decommissioning for repair.
The monitoring time interval, starting with preparation for measurements and up to fulfillment of regulations, should be significantly shorter than the malfunctions development interval from the moment of detection to a critical level. Results of the units large-scale monitoring at petrochemical complexes show that the minimal intervals of malfunctions development up to critical levels do not exceed 10-20 minutes, but they can be significantly shorter – up to 3-5 minutes – due to the “human factor” adverse effect. The necessity to prevent accidents caused by such factors has determined emergence of automatic stationary systems for health monitoring of hazardous production facilities units, primarily in petrochemistry, metallurgy and railway transportation.
Thus, the radical difference between monitoring and diagnostics lies in necessity of taking into account the time factor. This gives us the following definition of the unit health monitoring (unit monitoring) - monitoring of the unit technical state (design of machine, unit, mechanism) for determination and prediction of entering the limiting state. Monitoring is diagnostics, expanded in time. The fundamental difference between health monitoring and parameters monitoring is the presence of the measured parameters interpreter in terms of the unit technical state (expert system for decision-making support on the unit health and further control).
Kostyukov V.N. Systems for real-time comprehensive health monitoring of equipment // NEFTEGAZ. - 2010. - pp. 44-45
A structural mathematical description of a vibroacoustic signal, obtained from a piston machine specific units with regard to a channel of vibroacoustic oscillations formation and distribution, is a diagnostic model. This model allows to select informative diagnostic features of malfunctions and defects.
The generalized structural model of the vibroacoustic signal, generated by different sources in the piston machine, is built in the presence and interaction of three main sources of vibro-acoustic oscillations in the unit, which are is identified by oscillations types: free damped, forced undamped, random broadband and narrowband oscillations.
In order to form the diagnosis-making algorithms, based on the vibroacoustic signal parameters and invariant to machines and mechanisms design, it is necessary to develop particular structural models of the vibroacoustic signal for a specific malfunction or defect on the basis of the generalized model.
Naumenko A.P. On some models of vibroacoustic signals structure in piston machines // Engine-2010. - 2010. - pp. 75-78