The method of determining the polarization potential during corrosion surveys of underground pipelines

2020 ◽  
Vol 10 (2) ◽  
pp. 186-193
Author(s):  
Andrey А. Bolotov ◽  
Keyword(s):  
Cathodic Protection ◽  
Field Tests ◽  
Original Method ◽  
Polarization Potential ◽  
Operating Conditions ◽  
Measuring Instruments ◽  
Polarization Current ◽  
Protection Efficiency ◽  
Underground Pipelines ◽  
Experimental Use

Values of metal potentials, which exceed or equal to the potential at which the corrosion rate of the metal does not exceed 0.01 mm/year, in international practice, are a condition for the effectiveness of cathodic protection of underground pipelines. It is called polarization potential. The range of polarization potentials, which correspond to effective corrosion protection, was determined experimentally as a result of a large number of field tests in different operating conditions. The values of polarization potentials can vary from minus 0.65 V to minus 1.15 V, measured relative to copper sulfate electrode (C.S.E). There are cases during corrosion surveys of underground pipelines, when the measured values of polarization potentials with the help of measuring instruments, intended for this purpose, significantly exceed the maximum permissible value. The author offers an original method for determining the polarization potential based on the analysis of the dependence of the auxiliary electrode potential on the time after the interruption of the polarization current. The values of polarization potentials obtained using this technique are in the standard range. The method can be recommended for experimental use in corrosion surveys of underground pipelines in various operating conditions in order to confirm the compliance of the obtained results with the condition of cathodic protection efficiency.

scholarly journals On the pipeline polarization in the case of insulation delamination from its surface

2020 ◽  
Vol 2020 (1) ◽  
pp. 40-45
Author(s):  
V. V. Lukovych ◽  
Keyword(s):  
Current Density ◽  
Cathodic Protection ◽  
Polarization Potential ◽  
Polarization Current ◽  
Protection Zone ◽  
Average Value ◽  
The Earth ◽  
First Case ◽  
The Difference ◽  
Protection Potential

The cathodic protection parameters for two pipelines with a diameter of 1420 mm were calculated. The protection zone for the first pipeline is 6 km long and for the second one it is 5 km. The cathode station current is 12,9 A for the first pipeline and 4 A for the second one. There are a damage and detachment of pipeline insulation, andconsequently a thin layer of electrolyte is located in the detachment area between the metal surface and the insulation. Almost the entire surface of the pipeline has polarization potential. For the first pipeline, the values of the protection potential at neighboring measurement points change quite dramatically, the difference between them can reach tenths of a volt. The polarization current density at the ends of the protection zone is quite small, and accordingly the polarization potential is close to the corrosion potential. But in the vicinity of the drainage point, these values are much larger. The situation is almost the opposite for the second pipeline, where the cathode station current is 4 A. The current density is almost equally distributed throughout the protection zone, slightly larger at its ends. The polarization potential changes accordingly. Its values are larger than the first case. In the cathodic protection, the potential of the pipeline relative to ground zero is important. Its average value depends on the magnitude of the cathode station current. Its graph intersects the lower part of the protection potential graph in the first case and the middle of the graph in the second. The protection potential is the difference between the potential of the pipeline and the earth surface. In the first case, in the vicinity of the drainage point this difference is much larger inside compared to the ends of the zone. As a conclusion, in the practice of cathodic protection it is important to regulate the value of the cathode station current in order to achieve the optimum protection. Keywords: delamination, protection potential, polarization current density.

Sacrificial Protection Efficiency Calculations Based on the Results of Stochastically Simulating the Parameters

2021 ◽  
Vol 410 ◽  
pp. 566-571
Author(s):  
Svetlana S. Vinogradova ◽  
Ramilya F. Tazieva ◽  
Anna N. Akhmetova
Keyword(s):  
Operating Conditions ◽  
Oil Refining ◽  
Environmental Aspects ◽  
Protection Level ◽  
Protection Efficiency ◽  
Internal Surfaces ◽  
Protection Systems ◽  
Active Protection ◽  
Refining Processes ◽  
Sacrificial Protection

Unique corrosion conditions in oil refining processes lead to the necessity of using passive and active protection systems, aimed at preventing from damages and ensuring the correct operating conditions of machines. To prevent from the development of corrosion processes on the internal surfaces of horizontal settlers, sacrificial protection is used. Before installing such a protection, they usually calculate the number of protectors to be installed in parallel. Some inputs are stochastic by their nature, which should be considered in assessing the risk of non-achieving the required protection level. The probabilistic model proposed to calculate the parameters of sacrificial tank protection that allows performing an exploratory design based on considering various environmental aspects to decide on the efficiency of sacrificial protection and to assess the achievement of the required protection level.

scholarly journals Analysis of Capacitance to Ground Formulas for Different High-Voltage Electrodes

Energies ◽  
2018 ◽  
Vol 11 (5) ◽  
pp. 1090 ◽  
Author(s):  
Jordi-Roger Riba ◽  
Francesca Capelli
Keyword(s):  
High Voltage ◽  
Fem Simulation ◽  
Operating Conditions ◽  
Power Supplies ◽  
Measuring Instruments ◽  
Stray Capacitance ◽  
Analytical Formulas ◽  
Circular Rings ◽  
Available Information ◽  
Limited Scope

Stray capacitance can seriously affect the behavior of high-voltage devices, including voltage dividers, insulator strings, modular power supplies, or measuring instruments, among others. Therefore its effects must be considered when designing high-voltage projects and tests. Due to the difficulty in measuring the effects of stray capacitance, there is a lack of available experimental data. Therefore, for engineers and researchers there is a need to revise and update the available information, as well as to have useful and reliable data to estimate the stray capacitance in the initial designs. Although there are some analytical formulas to calculate the capacitance of some simple geometries, they have a limited scope. However, since such formulas can deal with different geometries and operating conditions, it is necessary to assess their consistency and applicability. This work calculates the stray capacitance to ground for geometries commonly found in high-voltage laboratories and facilities, including wires or rods of different lengths, spheres and circular rings, the latter ones being commonly applied as corona protections. This is carried out by comparing the results provided by the available analytical formulas with those obtained from finite element method (FEM) simulation, since field simulation methods allow solving such problem. The results of this work prove the suitability and flexibility of the FEM approach, because FEM models can deal with wider range of electrodes, configurations and operating conditions.

scholarly journals Test Results of a Polymer Radiator of MTZ-80 Tractor Cooling System

2020 ◽  
Vol 14 (1) ◽  
pp. 55-60
Author(s):  
O. N. Didmanidze ◽  
R. T. Khakimov ◽  
E. P. Parlyuk ◽  
N. A. Bol’shakov
Keyword(s):  
Heat Transfer ◽  
Steady State ◽  
Cooling System ◽  
Operating Mode ◽  
Aerodynamic Characteristics ◽  
Operating Conditions ◽  
Hydrodynamic Resistance ◽  
Measuring Instruments ◽  
Research Areas ◽  
In Series

Global car manufacturers wish to increase the number of manufactured products, reduce their cost and labor input. The choice of research areas, design and technological developments in radiator construction is an extremely important and urgent task, due to the mass production of radiators for tractors and automobiles on the one hand, and the favorable development prospects of these interrelated industries, on the other. (Research purpose) To substantiate theoretically and experimentally the use of a combined cooling system containing both aluminum and polymeric water radiators and similarly liquid-oil heat exchangers based on the four principles listed above on automobiles and tractors. (Materials and methods) The authors performed bench tests using a special wind tunnel to study the thermal and aerodynamic characteristics of a prototype tractor radiator with a polyurethane core. After reaching the steady-state operating mode of the installation, the experimental values were determined for the control and measuring instruments. (Results and discussion) The authors carried out measurements of all parameters of both coolants in series at each steady-state operating mode of the bench. They obtained the main indicators dependences (reduced heat transfer, aerodynamic and hydraulic drag) of the heat exchanger, close to the operating conditions of the vehicles. (Conclusions) A prototype MTZ-80 radiator with a polyurethane core has great prospects as a future alternative radiator. An increase by 10-15 percent in the radiator heat transfer is possible by using aluminum fi ns on the surface of the polyurethane plate. A 15-20 percent reduction in hydrodynamic resistance is achieved by increasing the diameter of the capillary throughput in a polyurethane plate and the number of plates themselves in the radiator cell.

scholarly journals Digital Data Processing Methods for Estimating Tractive Force of Tractors

2021 ◽  
Vol 31 (1) ◽  
pp. 127-142
Author(s):  
Vyacheslav F. Fedorenko ◽  
Vitaly E. Tarkivskiy ◽  
Nikolay P. Mishurov ◽  
Nikolay V. Trubitsyn
Keyword(s):  
Real Time ◽  
Strain Gauge ◽  
Impulse Noise ◽  
Median Filter ◽  
Digital Processing ◽  
Operating Conditions ◽  
Measuring Instruments ◽  
Important Indicator ◽  
Tractive Effort ◽  
Useful Signal

Introduction. When carrying out an energy assessment of agricultural machines and traction tests of tractors, the most important indicator is the value of the tractive effort. The existing methods for determining the tractive effort of tractors imply the use of specialized measuring instruments, such as strain gauges and devices for processing and displaying information. The accuracy of determining the tractive effort is significantly influenced by the physical and mechanical properties of soil. To process the useful signal during the measurement of tractive effort, the data stream of the strain gauge sensor must be subjected to additional digital filtering taking into account the operating conditions of the agricultural unit. Materials and Methods. The functions of changing the tractive effort obtained on the K-744R2 tractor in various gears have been analyzed. An algorithm for digital processing of the signal of a strain gauge force meter based on a median filter has been developed that makes it possible to increase the measurement accuracy. The advantage of the proposed method is the ability to cut off sharp short-term impulse noise and sharp fluctuations in the amplitude of the measured value. Results. A method for determining the amount of tractive effort using median signal processing has been proposed. A device for determining the tractive effort during testing of agricultural tractors and units has been developed. The choice of the main components of the device for determining the magnitude of the tractive effort has been substantiated. As a result of the research, a device for measuring and digital processing of the signal of a force meter based on a microcontroller and specialized software for processing initial data in real time was designed and manufactured. Discussion and Conclusion. The developed method makes it possible to exclude the negative effect of impulse noise arising in the process of measuring the tractive effort of the tractor. The proposed device for measuring the tractive effort of tractors is compatible at the level of the exchange protocol with existing devices, has a high speed of operation in real time, multi-channel operation.

Prevention of Low-Frequency Vibration of High-Capacity Steam Turbine Units

1997 ◽  
Author(s):  
H. Kanki ◽  
Y. Kaneko ◽  
M. Kurosawa ◽  
T. Yamamoto ◽  
Y. Yamamoto ◽  
...  
Keyword(s):  
High Pressure ◽  
High Capacity ◽  
Low Frequency ◽  
Field Tests ◽  
Operating Conditions ◽  
Squeeze Film ◽  
High Pressure Turbine ◽  
Solution Approach ◽  
Vibration Excitation ◽  
Low Frequency Vibration

Abstract The causes of low-frequency vibration (subsynchronous vibration) of a high pressure turbine were investigated analytically and also via vibration excitation tests on actual machines under operation. From the results, it was concluded that low-frequency vibrations may be caused by either the decrease of the rotor system damping or by external forces, such as flow disturbance in the control stage and the rubbing between the rotor and casing. After identifying the cause of the low-frequency vibration, appropriate countermeasures such as installation of a squeeze-film damper and modification of valve opening sequence were taken. Vibration measurements and vibration excitation tests for the high pressure turbine under actual operating conditions were carried out in order to verify the validity of the countermeasures. These field tests confirmed that the problems of low-frequency vibration can be solved completely by taking the appropriate countermeasure depending on the cause of the vibration. This paper presents some field experiences of low-frequency vibration and the effective solution approach.

Computer system for metrological testing of location sensors used to monitor the patient's condition in magnetotherapy

2021 ◽  
Author(s):  
S.G. Gurzhin ◽  
V.L. Nguyen ◽  
A.V. Shulyakov
Keyword(s):  
Personal Computer ◽  
Physiological State ◽  
Objective Assessment ◽  
Metrological Certification ◽  
Linear Displacement ◽  
Operating Conditions ◽  
The Body ◽  
Measuring Instruments ◽  
Virtual Device ◽  
The Law

Non-contact monitoring of vital signs of a person is a reliable and safe way of promptly obtaining objective diagnostic information about the current physiological state of a patient during surgical operations, physiotherapeutic procedures or during sleep. The absence of direct contact of the sensors with the patient's body makes it possible to exclude the influence of a number of interfering factors, such as a violation or weakening of contact, which can lead to a deterioration in the quality of signals from the output of the sensors, a long-term location of the sensors on the body can have a psychological effect on the patient, changing his condition and thereby distorting the treatment method, etc. In order for the results of monitoring and diagnostics to be reliable and guaranteed accurate, it is necessary to carry out periodic metrological certification of location sensors, especially since many of them are of foreign production and their characteristics are either not standardized or do not meet the requirements of their operating conditions. Therefore, the tasks of developing methods and means for carrying out metrological tests of non-contact sensors for medical purposes are becoming urgent. Purpose – to show the possibility of implementing automated metrological tests of location sensors for medical use based on a personal computer and publicly available standard hardware and software. A method has been developed and implemented for conducting metrological tests of location sensors based on a personal computer, a digital dynamic measure of linear displacement, virtual measuring instruments, laser and ultrasonic sensors, as well as determining conversion errors in the LabVIEW environment. As an exemplary measuring instrument, it is proposed to use a webcam with a virtual device for recording the law of displacement in the LabVIEW Vison Development application. Full-scale experiments have been carried out, in which, using a digital measure of linear displacement, it is possible to reproduce with high accuracy almost any law of displacement and to regulate its informative parameters. Real movement signals were received with the help of virtual devices, recorded by two location sensors and a web camera. The errors of the means of registration are determined in comparison with the given digital method and analytically the law of movement. Introduction of the developed method and hardware and software for metrological certification of sensors of diagnostic channels of the systems of complex magnetotherapy «Multimag» and «Relaxmag». Carrying out automated metrological tests of sensors will ensure prompt, reliable and objective control of their actual characteristics, which means it will increase the effectiveness of treatment due to the prompt and continuous monitoring of the patient's functional state and an objective assessment of a number of important indicators.

Prospects for Using Carbon Nanotubes in Precision Instrument Engineering

2020 ◽  
Vol 992 ◽  
pp. 770-774
Author(s):  
A. Golikov ◽  
V. Pankratov ◽  
M. Barulina
Keyword(s):  
Carbon Nanotubes ◽  
Temperature Effects ◽  
Operating Conditions ◽  
Measuring Instruments ◽  
Precision Instrument ◽  
Equivalent Thermal Conductivity ◽  
Precision Measuring ◽  
Microstructured Optical Fiber ◽  
Commercial Scale ◽  
Actual Operating

This research deals with the prospects for application of modern nanomaterials as exemplified by carbon nanotubes for development of new classes of precision measuring instruments or for significant improvement of the performance of existing sensors and systems based on sensors. Carbon nanotubes have been known since the end of the 20th century, but production of high-quality carbon nanotubes on a commercial scale has become possible relatively recently, owing, inter alia, to researches of Russian scientists. Carbon nanotubes have unique properties which hold much promise for their use in different areas of science and technology. Thus, use of nanotubes in precision instrument engineering can solve a number of problems, such as increase in reliability, accuracy, durability, weight and size reduction, etc. Fiber optic gyroscopes based on microstructured optical fiber are considered in this research as an example to demonstrate that use of carbon nanotubes allows significant reduction of the temperature differences in the fiber and that such reduction, in its turn, leads to lower dependence of the FOG characteristics on the temperature effects under actual operating conditions. A mathematical model of the equivalent thermal conductivity of a microstructured fiber loop, all or some channels of which are filled with carbon nanotubes, has been developed in this research. A comparative analysis has been made of the distribution of heat in coils with the considered and traditional fibers under different temperature effects – harmonic, random and stepped.

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