A mathematical description for structure of a vibro-acoustic signal, obtained from a piston compressor specific assemblies with regard to the channel of vibro-acoustic oscillations formation and propagation, is a diagnostic model. This model allows to select the informative diagnostic features of the assembly malfunctions and defects.
One of the piston compressor most "problematic" assemblies is its valve. Number of valves per one cylinder usually ranges from four to eight and more. The report considers the model of vibro-acoustic oscillations, which have been converted into an electrical signal by dint of a sensor, mounted directly on the piston compressor valve or next to the valves group.
When considering the model, it was found that with an appropriate choice of locations for the vibro-acoustic signals sensors (on the piston compressor appropriate assemblies) one can diagnose the malfunctions occurrence in a double-acting piston compressor assemblies according to correlation of the second and more high-and low-frequency harmonics levels in an envelope spectrum of vibro-acoustic signals. Taking into account a modulation degree high sensitivity to changes in a modulating signal parameters, compared with a direct spectrum signal, it is advisable to use the frequency range that corresponds to a carrier frequency in vibro-acoustic oscillations, generated by gas flow.
Thus, the presented model of the vibro-acoustic signal allows to determine the most informative vibro-acoustic components, which can be used as the diagnostic features parameters for malfunctions in valves and other piston compressor components and parts.
Naumenko A.P. Patterns for vibro-acoustic signals of piston machines // Science, education, business (“Nauka, obrazovanie, biznes”). - 2011. - pp. 114-120
Within limited financial resources, companies try to find ways to streamline all activities in order to achieve the best possible results at the lowest cost. Operation and repair of equipment in industrial enterprises play a leading role in solving this problem. Improving of the main and auxiliary personnel labor productivity, security and operational efficiency is of crucial importance, because there are no reserves, due to higher prices for products and expanding markets.
Operational efficiency of continuous production mostly depends on the amount of material and labor efforts for the equipment repair and on the amount of losses due to accidents and downtimes.
Growth of situational costs is induced by higher rate of material and labor resources waste due to lack of timely and targeted response to increase of the equipment wear rate caused by low observability of influencing factors in the conditions of a priori uncertainty.
The essence of technical management of hazardous continuous productions consists of early detection and purposeful influence on rate decreasing effect for material and labor resources waste during the equipment operation, which is provided by the monitoring systems implementation and effectiveness of the personnel actions in real time.
Kostyukov V.N., Kostyukov An.V., Makhutov N.A. Improving safety and operational efficiency of hazardous continuous productions // Monitoring and industrial risk management. Problems of diagnostics and non-destructive testing. - 2009. - pp. 53-65
Synthesis of diagnostic features, appropriate to the piston machines technical condition types, main failures and operation modes, arising both separately and simultaneously, and invariant to the machine construction - is an important issue. One step for this problem solution is to create the diagnostic signal model for the unit under test.
The most common model of the known is a batch action generalized model of a quasi-periodic vibroacoustic signal, proposed by V.N. Kostyukov.
This model shows that the frequency content of the low-frequency vibration spectrum and the vibroacoustic signal envelope, obtained by filtering in the high-frequency field and subsequent detection, are approximately equal. These spectra can be represented by an expansion in the characteristic frequencies, which can be divided into three groups. To evaluate the unit technical condition it is necessary to select and measure the components energy characteristics for each group.
This model describes large classes of the units under test failures. The model further development is the model, which describes the vibroacoustic signals with respect to their sources interaction, thus increasing the diagnosing accuracy and depth, but its use for developing the diagnostic algorithms is not obvious.
Therefore, it is advisable to consider a few examples of the vibroacoustic signal models when specific defects and failures occur, thus forming the piston compressors diagnostic features.
Naumenko A.P. Vibroacoustic model of the piston compressor diagnostic signal // Dynamics of systems, mechanisms and machines. - 2009. - pp. 39-44
The standard has been based on the Findings of Russian State Technical Supervision Service Committee, responsible for comprehensive monitoring systems for hazardous production facilities acceptance tests. The Committee has been created according to the Direction № R-20 from 2nd December, 2003, issued by deputy chief of Russian State Technical Supervision Service. These Findings compile a long experience in developing and implementation of real-time condition monitoring comprehensive systems for machinery and technological equipment of various industries hazardous facilities.
The standard is recommended for expert, design and industrial enterprises to help with selection and application of stationary piston compressor units in order to prevent technogenic accidents and to provide safe and resource-saving operation of equipment according to its actual technical condition.
The standard has been developed by DYNAMICS SPC: V.N. Kostyukov, A.P. Naumenko; SIU "RISCOM".
Condition monitoring of hazardous production facilities. Stationary piston compressor units of hazardous production facilities: operating vibration standards (STO 03-007-11) // Moscow: Compressor and chemical technics, 2012. - 18 p. ISBN 978-5-9902032-3-5
The tutorial considers theoretical and practical basis of machinery and mechanisms vibroacoustic analysis and malfunctions, as well as methods of vibroacoustic signals analysis.
The manual is intended for students who study disciplines ‘Automated systems for quality control and diagnostics’, ‘Methods of technical diagnostics’, ‘Vibration monitoring’ while their preparing to become specialists, masters and bachelors. The tutorial may be useful for post graduate students and specialists of non-destructive testing, who use the vibration analysis method for machinery condition monitoring and who design monitoring and diagnostic systems.
Kostyukov V.N., Naumenko A.P. Fundamentals of machinery vibroacoustic analysis and monitoring // Omsk: Publishing house of Omsk State Transport University, 2011. - 360p., ISBN 978-5-8149-1101-8
Automated Control System for Safe-Money-Saving Proactive Maintenance COMPACS® - ACS SMSPM™ COMPACS®
Accidents and breakdowns on railway transport have become more frequent, thus making seriously concerned about the infrastructure objects technical condition observation and control at different life-cycle levels.
Having synthesized more than 20 years experience of continuous hazardous production monitoring and diagnostics for petrochemical, metallurgical and mining industries, as well as experience of railway equipment diagnostics, DYNAMICS SPC develops actively the innovative technology of rolling-stock equipment technical state control, based on real-time condition monitoring - automated control system for safe-money-saving proactive maintenance COMPACS® - ACS SMSPM™ COMPACS®.
ACS SMSPM™ COMPACS® principal components are means of monitoring, diagnostics and integration:
systems for EMUs assemblies and units diagnostics at acceptance tests areas of workshops TR-2, TR-3 (COMPACS®-EXPRESS, COMPACS®-AGREGAT, COMPACS®-RPP);
systems for comprehensive diagnostics of EMUs sections at acceptance tests areas of workshops TR-2, TR-3 (COMPACS®-EXPRESS-TR3);
on-board systems for EMUs equipment technical condition monitoring (COMPACS®-EXPRESS-3);
diagnostic network Compacs-Net®, which unites monitoring and diagnostic systems and provides data submission to different operation and repair control levels.
In order to simplify the maintenance and technical support processes, all ACS SMSPM™ COMPACS® systems are built up on the base of common hardware and software, have a built-in function of sensors autodiagnostics and a general metrological base, including measuring channels verification/calibration methods.
An important feature of COMPACS® systems is a possibility of integration to the diagnostic network Compacs-Net®, implemented at the enterprise. Owing to Compacs-Net® the objective evidence about technical condition is available in real-time for the enterprise chiefs and actionees.
Looking ahead the means of control and diagnostics can be connected to Compacs-Net®, being located at the enterprises-manufacturers of componentry and equipment for rolling-stock and the infrastructure objects. This will allow to create a common information-diagnostic space for the effective technical condition control of railcar rolling-stock.
Kostyukov V.N. Innovative technologies of electric trains operation // Daily transport newspaper "Gudok". - 2012. - 12 July. - № 119 (25080)
The necessary completeness and depth of electric circuits diagnostics can be provided by means of resistance assessment of control circuits loops under consideration and high-voltage power and auxiliary circuits sections. Obviously, the current sensors mounting at each loop of control circuits is inexpedient, as in that case the diagnostic complex complication exceeds the diagnosed object complication in several times.
To determine the specified parameters with the minimal number of sensors and the diagnostic complex flow lines, a principle of control circuits functional-test diagnostics has been developed. The principle consists in determining of each branch diagnostic features through timely inclusion of the branch in the operational process. This inclusion is carried out by means of test impacts injection to the main and auxiliary inputs. The specific sequence of impacts makes them identical to working ones.
At the same time the high-voltage circuits switching units fulfill the assigned functions in the whole range of possible combinations. The use of additional inputs (impacts injection has not been foreseen by the operation working algorithm for these impacts) for test impacts injection even with functional impairment in the branches of control circuits, corresponding to the main inputs, allows to ensure the impact transfer to the actuator, thus performing their primary function.
Kostyukov Al.V., Kazarin D.V. The choice of diagnostic features for electric trains circuits // Nauka, obrazovanie, biznes (Science, education, business). - 2009. - pp. 189-194
Diagnostics of the rolling stock wheel-motor units is an urgent matter of today. Bearing assemblies of wheel-sets and wheel-motor units (WMUs) undergo enormous impact forces and their technical condition largely influences a train performance safety.
It is customary to use 6 vibration sensors which are mounted on the general bearing assemblies (axle bearings, reducer, traction motor). Nevertheless there is an opinion that such a number of sensors is abundant and only increases diagnostic operations time.
In order to determine capability of vibration sensors number reduction while diagnosing of an electric train wheel-motor units, studies on the mutual impact between different subjects diagnostic features have been carried out.
Zaycev А.V., Lagaev А.А., Kostyukov V.N. Capability determination of vibration sensors number reduction while diagnosing of an electric train wheel-motor units // Nauka, obrazovanie, biznes (Science, education, business). - 2009. - pp. 154-157
Operating safety level of units with piston compressors is determined by reliability of their technical condition monitoring, timeliness and accuracy of malfunctions and their causes detection. Nowadays there are numerous technical tools designed for piston compressors monitoring and diagnostics, which are developed and manufactured in different countries by various companies. However, it remains a pending issue if the measurements are adequate to the actual technical condition of piston compressors and to the risk magnitude of their safe operation. Although there is a document that defines the general requirements for critical industrial facilities monitoring systems, nevertheless even experts find it rather difficult to sort out the advertised systems capabilities. In this connection there is an urgent necessity to systematize the condition diagnosing and monitoring methods and means for piston compressors.
Almost all monitoring and diagnostic systems are characterized by:
determination methodology for technical condition of piston compressors units and components is based on measurement of direct structural and technological parameters (relative displacement, pressure, temperature) and implements an online technology;
expert systems use the values of direct structural and technological parameters;
parameters of indirect processes (vibroacoustic oscillations) are used to assess these parameters values without a diagnosis-making and detection of malfunctions and defects causes.
In the equipment vibration analysis system COMPACS® the methodology for real-time monitoring and diagnostics is based not only on the measurement of direct structural and technological parameters, but on the use of vibroacoustic oscillation parameters as well, there have been implemented algorithms of the expert decision support system with an autodetection (in the rate of diagnostic signals measurement) of more than 20 units malfunctions and defects and the degree of their danger.
Naumenko A.P. Analysis of modern methods and means of piston compressors condition monitoring and diagnostics // Nauka, obrazovanie, biznes (Science, education, business). - 2009. - pp. 107-115
EMUs electrical circuits are divided into low-voltage control circuits, high voltage power and auxiliary circuits and in general constitute a complex, multi-element, multiply object with feedback loops and a large number of parameters, and its reliable operation has a significant influence upon the security and uninterrupted functioning of the railway carryover conveyor.
A repair system, designed to maintain an acceptable reliability level of rolling-stock and based on the scheduled preventive principle, has already exhausted its resource of cheap, skilled labor force and is not currently able to provide a high level of safety, keeping to schedule and improving the transportation process quality while reducing costs. Lack of modern and reliable devices for technical condition monitoring is the main reason of EMUs defects and failures. According to the statistical accounting of «Russian railways» JSC, about 60% of these defects and failures occur in electrical circuits.
Achievement of a high efficiency and reliability in the technical condition assessment of complex objects is possible on the basis of technical diagnostics devices, which development and implementation is preceded by phases of the object study and the diagnostic algorithms synthesis.
Electrical circuits can be represented as a single discrete logic device, whose input, internal and output signals have two stable states, respectively, and for their analysis it is advisable to use the mathematical apparatus of logical algebra.
Kazarin D.V. Synthesis of algorithms for diagnostics of electric circuits // Omsk Research Journal. - 2009. - pp. 133-135