Researches of many years, experience of development, implementation, and operation of the systems for vibration analysis and condition monitoring of reciprocating compressors enabled to solve most scientific problems of development and practical use of the methods and principles of condition control, diagnosing and monitoring of the reciprocators by identification of technical condition of the objects according to initial information inherent in vibroacoustic signal. Practical solutions for the following problems have been found:
The set of diagnostic features corresponding with the forms of technical condition, major malfunctions (which emerge separately or at the same time) and operating practices of the reciprocators has been developed;
The standards for diagnostic features corresponding with the forms of technical condition and risk levels of malfunctions have been determined;
Automated systems for reciprocator condition monitoring, which enable accident-free operation, have been developed. In addition, they have been implemented at a number of Russian and foreign enterprises.
Naumenko A.P. Ensuring of safe operation of gas reciprocating compressors based on condition monitoring // Technical regulation and standardization. Risk management, industrial safety, control and monitoring: Proceedings of International Conference. - 2007. - p. 33-53
Long operation of various rotor machines is not allowed in case the number of revolutions is critical. During the start of electric motor, compressor and other machine equipment a critical number of revolutions should be passed as quickly as possible in order to eliminate the emergency.
Rotational velocity of machine equipment shafts is monitored by special devices called tachometers. DYNAMICS Scientific & Production Center (SPC) developed specialized explosion-protected remote tachometer for work in explosive zones where the use of ordinary tachometers is limited.
A remote tachometer is designed for use in the COMPACS® system for vibration analysis that is intended for condition monitoring of the equipment of refineries and petrochemical industries. This system is used for continuous monitoring of speed of motor shafts or any other equipment located in explosive zones.
Kostyukov V.N., Starikov V.A., Zub A.Y. Explosion-protected remote tachometer // Sensors and Systems. - 2007. - №10. - p. 47-48
Nowadays during schedule-based repair of MDRS in the depot conditions the pantograph parameters are often analyzed visually, by manual methods. At that an ordinary stop watch is used to measure the time of lifting and lowering of the pantographs, and a dial dynamometer is used to control static characteristic of pantograph pressing. More modern devices and systems are present primarily as single experimental samples.
Smart sensors equipped with microprocessors and wireless communication channels have become very popular recently. Modern smart sensors in comparison with traditional measuring devices ensure the following:
significant decrease in information distortion owing to digital signal transmission through communication channels;
increase of reliability owing to integral functions of self-diagnostics;
possibility of independent analysis of the measurement results through the algorithms for digital processing of the signals;
possibility of implementation of different algorithms for control of external devices, etc.
At the same time the use of smart sensors ensures significant reduction of costs owing to decrease in the cost of installation and maintenance, reduction of losses associated with minimizing of wired connections, decrease in human factor influence, etc.
The paper presents the results of creation and practical implementation of smart sensors system for automatic condition diagnostics of pantographs, which forms part of the COMPACS®-EXPRESS-TR3 (comprehensive system of smart sensors for electric multiple unit sections diagnostics) designed for diagnosing of wheel motor units, brake equipment, pantograph, electrical control circuits, power and auxiliary circuits, insulation of electric unit circuits.
Kostyukov V.N., Kostyukov Al.V., Starikov V.A. Condition monitoring of pantographs of motor driven rolling stock (MDRS) by the system of smart sensors // Sensors and Systems. - 2007. - №10. - p. 33-38
One of the main problems of diagnostics and monitoring of reciprocator condition is the analysis, selection and reasoning of diagnostic features set conforming to the types of technical condition and basic malfunctions of the reciprocators as well as creation and investigation of regulatory and procedural base of diagnostic features.
Fundamental methods of processing and analysis of reciprocator vibroacoustic signal may be divided into three groups:
analysis of variance of vibroacoustic signal in different frequency bands, for example, vibration acceleration, vibration velocity, vibration displacement (RMS value, amplitude);
amplitude-phase analysis, i.e. isolation by the time (shaft rotation angle) and the analysis of vibroacoustic signal parameters within the selected interval;
the signal isolation in the frequency range typical for particular element of the mechanism and the analysis of the parameters of the selected vibroacoustic signal.
On the basis of the model proposed in the article and in terms of well-known researches in the field of vibroacoustic diagnostics it is possible to state the following:
In general, vibroacoustic oscillations can be presented in the form of noise and periodic components.
Vibroacoustic signal at the sensor output is a superposition of oscillations of corresponding force actions and their mutually modulated components.
Such parameters of vibroacoustic oscillations as acceleration, velocity, displacement, and their variation in time during diagnostics are orthogonal diagnostic features of the malfunctions.
Naumenko A.P. Investigation of vibroacoustic parameters of the reciprocators // Engine-2007. - 2007. - p. 518-525
In the practice of vibration analysis and control the signals of vibration acceleration and vibration displacement are often not taken into account. They are considered to be interconnected with vibration velocity signal because these parameters are interrelated by differential-integral ratios. At the same time the search for orthogonal diagnostic characteristics and their use for evaluation of equipment condition is an actual problem because it significantly increases reliability of the diagnostics.
The results of fundamental investigations of vibration processes in machines and attached structures, which have been accomplished under the direction and with the participation of the authors, show that the development of various malfunctions of rotary machines causes diverse reaction of vibration acceleration, vibration velocity and vibration displacement parameters to these malfunctions. These cases indicate significant constriction of the range of diagnosing malfunctions when used only one of these parameters.
Thus, the problem of estimation of independence degree of the signals of vibration acceleration, vibration velocity and vibration displacement emerges.
Kostyukov V.N., Kostyukov Al.V. Orthogonality of the signals of vibration acceleration, vibration velocity and vibration displacement in vibration analysis problems // Engine-2007. - 2007. - p. 500-506
On the basis of the analysis of fundamental achievements in the field of theoretical and experimental investigations, which are aimed at determination of major defects and malfunctions of the reciprocators, and on the basis of the analysis of vibroacoustic signal parameters the problem of the reciprocator condition control has been stated. In addition, major challenges in the field of the diagnostics and condition monitoring of reciprocating compressors and internal combustion engines have been determined. The main sources of vibroacoustic oscillations of the reciprocators have been considered, the model of vibroacoustic signal has been proposed.
Naumenko A.P. Methodology of vibroacoustic analysis of the reciprocators // MSTU bulletin, special edition "Internal combustion engines". - 2007. - p. 85-93
The main challenges of the company services responsible for production maintenance are:
maximizing of process units run-to-failure period by eliminating of accidents and downtimes due to equipment failures;
minimizing of the stopping repair duration through targeted repairs of the equipment;
reduction of maintenance costs and losses by eliminating of inefficient unscheduled and schedule-based preventive repairs.
Thus, a key performance indicator of various technologies of equipment operation (equipment maintenance strategies) is the extent of their ability to solve each of the problems mentioned above.
The analysis of ten-year experience of operation of Automated Control Systems of Safe Resource-saving operation and Maintenance of equipment (ACS SRSM™) COMPACS® at eight largest petrochemical and oil-and-gas processing enterprises shows that COMPACS® is a reliable tool for protection from technogenic accidents, which are mainly caused by the mistakes of manufacturing personnel, and an indispensable tool for prompting of efficient decisions during the planning of the scope and terms of repairs, equipment replacement and estimation of its results.
The systems are an ideal tool for monitoring of performance discipline and workmanship of the personnel. They ensure observability of condition of manufactured, repaired and exploited equipment, controllability of its quality at all stages of life cycle, stability, safety and efficiency of production.
Kostyukov V.N., Kostyukov A.V. Resource-saving and safe operation of equipment - the strategy of XXI century // NEFTEGAZ. - 2007. - p. 36-37
The paper presents the results of development and application of the systems for diagnostics and monitoring of the quality of assembly and mounting of machines and assemblies, which are in general use at oil-and-gas enterprises. These systems are potentially productive for engineering because they are an effective tool of increasing the reliability and service life of the products without important reconstruction of industrial and technological basis and, consequently, huge expenditures. The advances have come about through the fact that the cost of diagnosed processes and equipment is way above the cost of the monitoring systems, which is especially important for a national economy today.
Kostyukov V.N., Boychenko S.N., Kostyukov Al.V., Kostyukov A.V. Monitoring of the quality of assembly, mounting and operation of units of fuel and energy complexes // Technologies of Fuel and Energy Complexes. - 2007. - №2. - p. 60-65
We offer a revolutionary approach to operation management which was developed in Russia and approved at the largest oil-and-gas enterprises of Russia and abroad. This approach is realised by means of human factor elimination from the process of technical state evaluation of equipment for control of its safe maintenance on the base condition monitoring in real time. It allows establishing an actual feedback from the sources of control - equipment of production complex and operating personnel. This technology is especially actual at present stage when essential increase of production processes at different branches of oil-and-gas complexes in the vast expanses of Siberia and the Far East is planned.
The given SM™-Technology is provided by implementation of Automatised Control Systems for Safe Maintenance and Resources Saving™ COMPACS® during all stages of lifetime of the equipment: from the development stage up to utilisation. Systems ensure monitoring of the equipment state and efficiency of the maintenance and operating personnel actions and represent in real time current information to the work places of technical personnel and engineering managers responsible for an operational multiplier of the enterprise business-process.
Kostyukov V.N., Kostyukov A.V. Increase of Oil-and-gas Enterprises Efficiency on the Basis of Safe Maintenance // World finance review. - 2007. - p. 48-49
Nowadays the problem of trouble-free, safe, observable operation of the reciprocator fleet (especially internal combustion engines and reciprocating compressors of oil-and-gas refining, chemical complexes) becomes urgent. In addition, that is a problem of the maximum resource exploitation solvable by development and implementation of the technology for diagnostics and monitoring of the reciprocator technical condition.
The result of technical diagnostics is the determination of values of structural parameters characterizing technical condition of the reciprocator, its units and parts. In order to estimate residual life in terms of the law of variation of controlled parameter during operation it is necessary to know its actual and limiting value. However, determination of actual value of many structural parameters is practically impossible in view of working reciprocator. Their determination during the reciprocator dismantling affects quality of the couplings of re-assembled reciprocator and changes the patterns of processes of interaction of parts in the couplings, which makes practical use of this method of data obtaining unacceptable. In this case, the diagnosing is carried out through indirect characteristics that are quantitatively evaluated by diagnostic characteristics. The analysis of the applicability of various methods for diesel engine (as an example) diagnosing shows that diesel engine malfunctions can be detected with the help of four basic methods: thermodynamic, parametric, spectral (‘metal in the medium’), vibroacoustic.
Considering the variety of primary transformers, secondary equipment and methods of the signal processing by all these methods we must conclude that the application of vibroacoustic method enables significant reduction of the costs of development, implementation and operation of the system for reciprocator technical diagnostics.
Naumenko A.P. The problems of reciprocator diagnostics // Nauka, obrazovanie, biznes (Science, education, business). - 2007. - pp. 84-92