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Journal articles on the topic 'Control of leak tightness of equipment'
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1
Fokanov, A. N., V. F. Podurazhnaya, and A. V. Tebyakin. "Mass spectrometric study of the leak tightness of products made of technical sintered beryllium." Industrial laboratory. Diagnostics of materials 87, no. 4 (2021): 26–31. http://dx.doi.org/10.26896/1028-6861-2021-87-4-26-31.
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Beryllium products exhibiting a low level of absorption of the radiation energy are widely used in scientific instrumentation design (x-ray technology, radiation detectors, etc.). We present the results of studying the leak tightness of products (disks, plates) made of technical sintered beryllium of standard purity and foil obtained by «warm» rolling from high-purity beryllium. The relevant standards and requirements for testing are given. The leak tightness control was performed using mass spectrometric helium leak detectors with forevacuum backing pumps (oil and dry diaphragm pumps) and specialized vacuum equipment. The parameters of tightness of samples made of technical sintered beryllium were determined. The level of the helium signal during blowing was (0.6 – 7.4) × 10–11 Pa · m3/sec, which corresponds to the tightness standard of foreign analogues and matches the requirements of domestic manufacturers of x-ray equipment. The data spread tended to increase due to the growth of the background value. The obtained results can be used to improve high-tech equipment intended for flaw detection, medical devices, rapid analysis of ore raw materials, radiation safety equipment, etc.
2
Maslennikov, Aleksandr, Ilya Zubkov, and V. Pautov. "Optical chemical sensor for solving leak detection problems." MATEC Web of Conferences 212 (2018): 01030. http://dx.doi.org/10.1051/matecconf/201821201030.
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The main features of the construction of gas analytical leak detection systems are noted, from the point of view of the sensitive element and the test substance (gas) used in the leak tightness control. It is shown that when checking the tightness of functioning systems, the standard leak detection equipment is of little use because it is impossible, in most cases, to use the specific test gases necessary for its operation. The use of solid-state gas analytical sensors for the construction of leak detection systems for operating process equipment is proposed. It is shown that one of the most suitable is the optical chemical sensor because of its low sensitivity to the humidity of the carrier gas, which, in such a process of leak detection, is atmospheric air. The properties of the proposed sensor are investigated, which are most important when used in leak detection systems. These parameters are the dynamic characteristics of the sensor, which are determined depending on the operating temperature and pressure of the sensor. The obtained data showed the prospects of using the investigated sensor and also allowed to outline ways of improving and optimizing its design.
3
Leskin, Sergey, Dmitry Shvetsov, Evgeny Trykov, and Aleksey Puzakov. "Analysis of acoustic leak signals for enhancing sensitivity of control due to the creation of effective diagnostic indicators." Nuclear Energy and Technology 4, no. 2 (2018): 141–47. http://dx.doi.org/10.3897/nucet.4.30775.
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Acoustic leak control systems (for instance, SAKT) are used at present for controlling leak tightness of equipment and pipelines, as well as for detecting in timely manner coolant leaks from the primary cooling circuit of nuclear reactor installations (NRI) during operation of power unit on different power levels in the modes of normal operation and during disturbances of normal operation. Time averaged dispersion of acoustic signal is used as the main diagnostic indicator for detecting leaks in these systems. Sensitivity of this indicator is determined by the exceedance by the signal of the preset threshold value which is defined in accordance with the background. Here, background values of acoustic signal depend on the operational modes of the equipment and do not allow in many cases determining coolant leak during early stages of leak development. New approach to the formation of diagnostic indicators for detecting loss of sealing in the circuit during early stage of development of coolant leak is suggested. Methodology for obtaining diagnostic indicators is based on the processing in different frequency bands of acoustic signal accompanying coolant leakage from the pipeline using the method of principal components. Efficiency of the developed methodology of coolant leak detection is illustrated by processing acoustic signals for experimental facility modeling coolant leakage in case of loss of sealing of the circuit. Even in the presence of significant acoustic background sensitivity of the method allows detecting leaks with significantly lower flow rates (up to five times smaller) than the conventional processing of acoustic signals. Implementation of the developed methodology will not require significant expenditures for upgrading already existing leak control systems operated at present on different NPPs.
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Leskin, Sergey, Dmitry Shvetsov, Evgeny Trykov, and Aleksey Puzakov. "Analysis of acoustic leak signals for enhancing sensitivity of control due to the creation of effective diagnostic indicators." Nuclear Energy and Technology 4, no. (2) (2018): 141–47. https://doi.org/10.3897/nucet.4.30775.
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Acoustic leak control systems (for instance, SAKT) are used at present for controlling leak tightness of equipment and pipelines, as well as for detecting in timely manner coolant leaks from the primary cooling circuit of nuclear reactor installations (NRI) during operation of power unit on different power levels in the modes of normal operation and during disturbances of normal operation. Time averaged dispersion of acoustic signal is used as the main diagnostic indicator for detecting leaks in these systems. Sensitivity of this indicator is determined by the exceedance by the signal of the preset threshold value which is defined in accordance with the background. Here, background values of acoustic signal depend on the operational modes of the equipment and do not allow in many cases determining coolant leak during early stages of leak development. New approach to the formation of diagnostic indicators for detecting loss of sealing in the circuit during early stage of development of coolant leak is suggested. Methodology for obtaining diagnostic indicators is based on the processing in different frequency bands of acoustic signal accompanying coolant leakage from the pipeline using the method of principal components. Efficiency of the developed methodology of coolant leak detection is illustrated by processing acoustic signals for experimental facility modeling coolant leakage in case of loss of sealing of the circuit. Even in the presence of significant acoustic background sensitivity of the method allows detecting leaks with significantly lower flow rates (up to five times smaller) than the conventional processing of acoustic signals. Implementation of the developed methodology will not require significant expenditures for upgrading already existing leak control systems operated at present on different NPPs.
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Tsybrii, I. K., N. S. Koval, and Zh N. Issabekov. "Study of Tapered Threads Parameters Affecting the Quality of the Oil Pipeline Connection." Advanced Engineering Research 22, no. 3 (2022): 242–51. http://dx.doi.org/10.23947/2687-1653-2022-22-3-242-251.
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Introduction. With the growth in the production and transportation of gas and oil, the urgency of the problem of tightness of the connection of pipes of the oil and gas range increases. The most common are coupling and streamline threaded connections. Threads of the buttress type, conical trapezoidal, and triangular threads are used. The tightness of the connection depends directly on their quality. The production of pipes and couplings is influenced by many factors. Examples include technological heredity, rigidity of technological equipment, its setting and resetting. The required connection quality is provided by the quality of the elements. The assembly should take into account the possibility of complete interchangeability. The second recommended option is a group assembling. In all cases, control operations are mandatory. The paper presents the results of studies on the distribution of pipe and coupling thread quality parameters in the batch.Materials and Methods. Fragments (tubular parts) of casing pipes with trapezoidal thread and increased tightness (CPTT) and with trapezoidal thread of the buttress profile were studied. They were randomly selected from different batches. When measuring, the samples were fixed in the chuck of 1I611P lathe. The measuring instrument was a clock type 0 accuracy class indicator with a stand. Generally accepted statistical methods were used to evaluate the data obtained.Results. The experiments have found how the tightness of the connection through the method of complete interchangeability is affected by the radial runout of the surfaces of the thread profile tops, the pipe chamfers, and the sealing belt.Discussion and Conclusions. Significant deviations of the values of the thread parameters from the permissible ones were found, which might cause a leak in the connection. Obtaining a high-quality and reliable connection is possible when assembling by the method of incomplete or group interchangeability.
6
Borisenko, V. V., V. A. Zakharov, and K. V. Zakharov. "CONTROL OF THIN-WALLED SCREENS OF EPITAXIAL INSTALLATIONS BY THE EDDY CURRENT METHOD." Industrial laboratory. Diagnostics of materials 85, no. 6 (2019): 42–46. http://dx.doi.org/10.26896/1028-6861-2019-85-6-42-46.
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The results of testing thin-walled welded joints (high-temperature assemblies of epitaxial installations) obtained by electron-beam welding using the eddy current method are presented. The tightness of those parts and assemblies is controlled by vacuum and compression leak detection methods, based on increasing the test gas concentration on the one side of the test surface and sampling it for mass spectrometric analysis on the other side. Helium mass spectrometric leak detectors are now widely used in aerospace, electronics and chemical industries, as well as in the instrument making industry and scientific research. The eddy current method provides a high scanning speed and allows timely detection of the defects and prevention of the risk of accidental wear of thin-walled elements and parts of aerospace and petrochemical equipment. The goal of this work is to optimize the control of welded joints of thin (0.2 and 0.5 mm) tantalum screen using a VEKTOR-60D detector and eddy current method. The device provides the use of overhead or flow eddy current differential, tangential and absolute transducers operating at a frequency from 10 Hz to 20 MHz, as well as various dynamic transducers. The device is designed to control metal products, carbon plastics and composites for the presence of defects such as surface and subsurface cracks, discontinuities and homogeneity of materials. VEKTOR-60D allows one to get a simultaneous signal display on the flaw detector screen both in the amplitude-time and complex planes. The used sensors (PVDT-1000-2, PVD-200-2,3, and VP160A45) provided detection of the defects across the entire width of the weld and heat-affected zone in one pass along the welded joint. The defect of the welded joint of the tantalum screen was revealed as incomplete penetration (nonpenetration in the weld root) in accordance with the classification of GOST R ISO 6520-1–2012. The results proved that a VEKTOR-60D eddy current detector can be successfully used in monitoring defects in thin-walled welded joints.
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Guo, Zeyuan, Shaowei Hu, Wencan Jin, Yuxiao Ye, and Changxi Shan. "Application of Digital Twin in the Industry of Axial Hollow-Wall Pipes." Applied Sciences 13, no. 14 (2023): 8093. http://dx.doi.org/10.3390/app13148093.
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With the increasing demand for automation in agriculture, more and more researchers are exploring the application of digital twin in agricultural production. However, existing studies have predominantly focused on enhancing resource utilization efficiency and improving irrigation control systems in agricultural production through the implementation of digital twins. Unfortunately, there is a noticeable research gap when it comes to applying digital twins specifically to buried water conveyance pipelines within an agricultural irrigation infrastructure. Focusing on the long-term performance requirements of buried pipelines in agricultural irrigation and drainage, this study established a digital twin system for the industry of axial hollow-wall pipes with an outer diameter of 200 mm, specifically designed for this field of operation. The system was used to optimize the end-forming process of axial hollow-wall pipes, resulting in improved leak tightness under internal pressure and angular deflection of the pipes. The study suggests that the most effective method for the end-forming process of axial hollow-wall pipes is to heat the pipe for 60 s at the ambient temperature of 15 °C, with heating temperatures of 225 °C on both the inner and outer sides. Additionally, preheating the stamping equipment to 70 °C and controlling the cooling temperature, during pipe detachment, to between 35 °C and 45 °C is recommended. In terms of the leak tightness under internal pressure and angular deviation, the study found that increasing the thickness of the protruding end of the sealing ring to 16 mm, and shortening the chamfer length to 20 mm, while maintaining the same slope, can enhance the sealing effectiveness of the pipeline interface. The implementation of the digital twin system improves the production efficiency of the hollow pipe production line during the end-forming process, resulting in a yield rate of the pipe of up to 95% for qualified products. Moreover, the system provides intelligent closed-loop feedback which ensures the long-term operation and maintenance of the pipelines, making it easier to identify problems and implement design improvements. By doing so, it contributes to ensuring the long-term stability of related agricultural production.
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Сердобинцев, С. П., Н. С. Будченко, and Н. А. Долгий. "Automation of control and management of enhanced safety canned fish production." MORSKIE INTELLEKTUAL`NYE TEHNOLOGII), no. 4(50) (December 17, 2020): 76–80. http://dx.doi.org/10.37220/mit.2020.50.4.075.
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В статье рассматривается комплекс вопросов, способствующих повышению безопасности рыбных консервов как важнейшего показателя качества пищевого продукта и оптимизации расхода ресурсов. Показана целесообразность замены традиционного метода орошения блоков замороженной рыбы на электроконтактный способ, который существенного повышает производительность и улучшает качество размороженного сырья. Уменьшение ручного труда в рыбоконсервном производстве может быть достигнуто использованием роботов и робототехнических комплексов на стадиях приемки и порционирования сырья, фасования продукта, проверки герметичности и удаления негерметичных консервов. Применение системы технического зрения позволяет организовать непрерывный дистанционный контроль закаточного шва и изменять параметры настройки закаточной машины с целью достижения необходимой герметичности. Показано, что безопасность производства консервов может быть повышена облучением рабочих поверхностей продукта и оборудования ультрафиолетовым излучением. На безопасность консервов оказывают влияние практически все технологические операции рыбоконсервной линии. Анализ работ по технологии продуктов из гидробионтов и созданию автоматизированных консервных линий позволил выделить мероприятия по дальнейшему совершенствованию производства и хранения рыбных консервов. The article deals with a set of issues that contribute to improving the safety of canned fish as an important indicator of food quality and the resource consumption optimization. The utility of replacing the traditional method of irrigation of frozen fish blocks with an electric contact method is shown, the latter significantly increasing productivity and improving the quality of thawed raw materials. Reduction of manual labor in fish canning production can be achieved by using robots and robotic systems at the stages of acceptance and portioning of raw materials, product packaging, leak testing and removal of leaky canned food. The use of a technical vision system allows to organize continuous remote control of the sealing seam and change the settings of the sealing machine in order to achieve the necessary tightness. The safety of canned food production is shown to be increased by irradiating the working surfaces of the product and equipment with ultraviolet radiation. The safety of canned food is influenced by almost all technological operations of the fish canning line. The analysis of investigations into the technology of products from hydrobionts and the development of automated canning lines has allowed to identify measures to further improve the production and storage of canned fish.
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Bobrov, V. T., V. M. Bobrenko, and A. V. Gulshin. "ACOUSTIC EXPRESS METHOD FOR MEASURING ELASTIC METAL CONSTANTS OF HIGH-LOADED CONSTRUCTIONS WORKING IN EXTREME CONDITIONS. PART 1." Kontrol'. Diagnostika, no. 264 (June 2020): 46–63. http://dx.doi.org/10.14489/td.2020.06.pp.046-063.
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A review of contingencies related to the failure of potentially hazardous equipment of the aviation and space-rocket complexes showed that they lead to explosions, fires, deaths and destruction of infrastructure. The causes of accidents and disasters are errors in the selection of technical solutions and materials during design, imperfection of algorithms and software for flight control systems, malfunctions in on-board computers and security systems, navigation systems, engine failure, defects in components and assemblies. Examples of accidents and disasters related to technical failures leading to a violation of the tightness of the aircraft fuselage and depressurization of spacecraft are given. It is shown that the main types of damage to the units are corrosion damage, fatigue and metal wear. The conclusion is made about the negative impact of the “human factor” regarding the adoption of erroneous decisions, failure to comply with regulatory requirements and actions in extreme situations. There is a risk of fatigue cracks and degradation of the properties of stringer metal, landing gear struts, wing tail trim, fuel tanks, engine pylon flanges, and imperfect methods, equipment, and technology for monitoring fatigue defects of critical components and mechanisms of aircraft, helicopters, and space systems. It is shown that modern achievements are poorly used in research and development of physical methods and diagnostics of elastic constants of metals working under high pressure, their changes in conditions of wide temperature drops, cosmic vacuum, vibration and other influences. It is proposed to combine efforts with scientists and experts in the field of strength, resource assessment and operational safety of aviation and space technology.
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Bobrov, V. T., V. M. Bobrenko, and A. V. Gulshin. "ACOUSTIC EXPRESS METHOD FOR MEASURING ELASTIC METAL CONSTANTS OF HIGH-LOADED CONSTRUCTIONS WORKING IN EXTREME CONDITIONS. PART 1." Kontrol'. Diagnostika, no. 264 (June 2020): 46–63. http://dx.doi.org/10.14489/td.2020.06.pp.046-063.
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A review of contingencies related to the failure of potentially hazardous equipment of the aviation and space-rocket complexes showed that they lead to explosions, fires, deaths and destruction of infrastructure. The causes of accidents and disasters are errors in the selection of technical solutions and materials during design, imperfection of algorithms and software for flight control systems, malfunctions in on-board computers and security systems, navigation systems, engine failure, defects in components and assemblies. Examples of accidents and disasters related to technical failures leading to a violation of the tightness of the aircraft fuselage and depressurization of spacecraft are given. It is shown that the main types of damage to the units are corrosion damage, fatigue and metal wear. The conclusion is made about the negative impact of the “human factor” regarding the adoption of erroneous decisions, failure to comply with regulatory requirements and actions in extreme situations. There is a risk of fatigue cracks and degradation of the properties of stringer metal, landing gear struts, wing tail trim, fuel tanks, engine pylon flanges, and imperfect methods, equipment, and technology for monitoring fatigue defects of critical components and mechanisms of aircraft, helicopters, and space systems. It is shown that modern achievements are poorly used in research and development of physical methods and diagnostics of elastic constants of metals working under high pressure, their changes in conditions of wide temperature drops, cosmic vacuum, vibration and other influences. It is proposed to combine efforts with scientists and experts in the field of strength, resource assessment and operational safety of aviation and space technology.
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Yalçın, Barış Can, and Ahmet Koyun. "Linear matrix inequality-based model matching H2 output feedback control of a new leak tightness machine working based on hydrostatic pressure aging method." Transactions of the Institute of Measurement and Control 40, no. 5 (2017): 1711–25. http://dx.doi.org/10.1177/0142331217690224.
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Fluid leaks owing to broken pipes can be a serious problem for any hydraulic system. The main reasons for pipe breakage are spontaneously changing hydrostatic and hydrodynamic pressure values inside the pipe or faults occurring during the pipe manufacturing process. Therefore, different kinds of leak tightness tests are required in many standards for approval of the pipes used in both academic researches and industrial applications. Hydrostatic pressure aging is the most common method among leak tightness test procedures. However, conventional test machines cannot reach above 700 bar owing to their mechanical specifications. In this study, the design of a new leak tightness test machine that can reach above 1200 bar and its Linear matrix inequality-based model matching H2 output feedback control have been achieved. The efficacy of the test machine and proposed controller have been shown with both simulation and experimental results.
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Ulutaş, S., M. Wichern, and B. Bosseler. "Laboratory investigations on the quality of leak tests and visual inspections of wastewater connection pipes carried out by specialist contractors." Water Practice and Technology 17, no. 1 (2021): 91–101. http://dx.doi.org/10.2166/wpt.2021.095.
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Abstract In addition to stability and operational safety, leak tightness is the permanent functional objective of wastewater pipes. Tests to determine the tightness of wastewater pipes can in some cases produce results that are worthy of discussion. Therefore, laboratory tests were carried out by 29 specialist contractors to obtain results on the quality of leak tests and visual inspections of connection pipes. The results showed that different test errors can be observed for leak test methods (air overpressure, air underpressure and water pressure). However, only in the case of the water pressure tests did the observed test errors occasionally lead to incorrect test results, i.e. the ‘leaking pipe’ was tested as ‘test passed (tight)’. The investigations into the accuracy (trueness and precision) of the test methods showed that all test methods examined were sufficiently accurate to determine the tightness of the connection pipes. In general, correct test results were achieved if the expert testers did not make any serious test errors and the test equipment used functioned properly. In contrast, the investigations on the quality of visual inspection showed that the procedure is not sufficiently reliable to fulfil all normative requirements regarding damage detection and naming as well as damage classification.
13
Yudina, Z. A., M. I. Sinichenko, A. P. Ladigin, F. K. Sin'kovskiy, and A. D. Kuznetsov. "Valve for two-phase fluid loop." Spacecrafts & Technologies 5, no. 2 (2021): 82–88. http://dx.doi.org/10.26732/j.st.2021.2.03.
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Improvement of heat transfer efficiency of the spacecraft thermal control subsystem constitutes a relevant problem for today space industry. Two phase thermal control system presents the most suitable solution for this problem. Implementation of reliable thermal control loop elements constitutes one the major prerequisites for reliability of thermal control systems featuring the operating pressure of 4.8 MPa and ammonia as heat fluid. This paper presents the design and test results of manual valve and fill and drain valve to be operated within the spacecraft two phase thermal control subsystem. The paper provides considerations and detailed description of the technical solutions adopted to ensure compliance with the specification requirements such as operating pressure and plug seat leak tightness under the operating pressure and 160 open/close cycles. Valve plug torque selection criteria are described. The employed design and technical solutions as well as qualification test results have proven that the units designed feature outstanding combination of performances such as leak tightness, life cycle with ammonia as heat fluid.
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Makarov, V. A., and F. A. Korolev. "The leak detection process modeling." Journal of Physics: Conference Series 2373, no. 2 (2022): 022033. http://dx.doi.org/10.1088/1742-6596/2373/2/022033.
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Abstract The paper describes formalized description concept of the expiration gas process through product manufacturing defects in the control of tightness: Model Internal description based on the use of parameters of circuit theory and mathematical model of the external description made by means of functional expansions obtained on the basis of mathematical models experimental research of the implemented software package external description. A dynamic model of the outflow of gases through product defects is presented by the Wiener-Voltaire equations. The proposed method for studying the outflow of gases through product defects consists a simulation object whose input is subjected to an external action with constant other variable parameters and registration of the output signal. The experimental data are compared with the results of theoretical calculations based on the molecular model of the outflow process.
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Zhang, J., P. Arnold, J. Fydrych, P. Nilsson, M. Chorowski, and J. Polinski. "Seat leak tests and commissioning of control valves in the cryogenic distribution system of the ESS superconducting linac." IOP Conference Series: Materials Science and Engineering 1327, no. 1 (2025): 012016. https://doi.org/10.1088/1757-899x/1327/1/012016.
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Abstract The European Spallation Source (ESS) is a neutron-scattering facility which will use a pulsed 2.0 GeV proton beam generated in the linear accelerator (LINAC) for releasing high-energy neutrons in the ESS target station. The 2K superconducting linac comprises 13 spoke and 30 elliptical cryomodules. The cryogenic distribution system (CDS) connects the cryogenic plant with the 43 cryomodules through a 400 meters long cryogenic multi-transfer, 43 valve boxes and an endbox. The CDS consists of 373 control valves in total. There are 8 and 10 control valves in each elliptical and spoke valve boxes, respectively, and 3 valves in the end box. The control valves are used for regulating or blocking the process helium flows. The seat tightness of the CDS valves is crucial especially for warming up individual cryomodules, which is required for potential short-term maintenance or repair activities in the cryomodule while keeping the others in cryogenic conditions. What is more, leaks over valve seats might cause moisture or ice formation on room temperature uninsulated pipes for warmup and cooldown valves or add heat load to the cryogenic system. Valve initialization and leak tightness tests were firstly performed with warm helium in the second half of 2022 before the first CDS cooldown. The tests revealed many leaks above the specified acceptable leak rate of 10-4 mbarl/s with several of them reaching even 102 mbar.l/s. The major bulk of those leaks were fixed before and after the 2nd CDS cooldown that followed in 2023. This paper describes the seat leak test method and results, as well as the possible causes of the observed leaks, the taken solutions for repairing the insufficiently tight valves and the prevention for valve seat leak.
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Raunmiagi, Zygmunt, and Piotr Bielawski. "Identification of the Water-Cooled Fuel Injectors for Engines." Key Engineering Materials 588 (October 2013): 134–39. http://dx.doi.org/10.4028/www.scientific.net/kem.588.134.
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The fuel injector acts a double role: it is the valve of the pump supplying fuel to the combustion chamber and the device spraying a supplied dose. As the valve it may operate as a self-opening or self-closing valve, depending on the pressure produced by the fuel pump, or the valve controlled by external signals. Techniques and diagnosis methods for fuel injectors depend on a fuel injectors control system and construction details. For practical reasons the fuel injector is a sectional valve with a separated component called atomizer. Atomizers must be cooled. It is possible to cool with fuel or with external water-or oil-cooling system. In case of liquid-cooled fuel injectors, apart from malfunctions causes known from literature, decrease of the cooling efficiency may appear, as the effect of the penetration of fuel from injector to the cooling system of injector. There are no reports concerning detectability of fuel leakage into cooling liquid with known techniques and diagnosis methods of injection systems and fuel injectors. In the article there will be presented as follows: a connection of the atomizer and injector body as the place of fuel leakage into the cooling system, reasons for loss of leak tightness in connection of atomizer with the body of atomizer and methods applicable for the leak tightness analysis, mechanisms of injectors malfunction caused by the loss of leak tightness. The analysis of applied and possible methods of injectors diagnosis in the aspect of identification of said leakiness will be carried out.
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Alexopoulos, T., E. Gazis, S. Maltezos, et al. "Gas System for the ATLAS NSW Micromegas Detectors: Design Aspects and Advanced Validation Methods for their QA/QC." HNPS Proceedings 24 (April 1, 2019): 23. http://dx.doi.org/10.12681/hnps.1839.
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In this work we present the design aspects of the Gas Distribution System of NSW Micromegas detectors, simulation results and gas flow / pressure uniformity. We also describe the appropriate gas leak test methods, a conventional and an alternative one, being used in the Quality Assurance and Quality Control of the detectors. For the performance studies we used emulated leak branches based on medical needles. We also describe proposed upgrade stages combining the proposed competitive Flow Rate Loss method with the Lock-in Amplifier technique. Further, we describe the baseline setup for the Gas Tightness Station at BB5/CERN.
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Mladenov, Evlogi, Danail Gospodinov, and Rossen Radev. "Leak rate investigation of expanded polytetrafluoroethylene flat gasket." E3S Web of Conferences 413 (2023): 04011. http://dx.doi.org/10.1051/e3sconf/202341304011.
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This article examines expanded polytetrafluoroethylene (PTFE) flat gaskets used in the industry to seal flange connections that prevent mixing of working fluids and leakage of fluids into the environment. Expanded PTFE gaskets and existing solutions to improve tightness are reviewed. Using test equipment for measuring the mass of gas passed through the gasket per unit time, which is one of the main operating characteristics of the gasket, a comparison of the required contact stress applied to the gasket during installation to achieve the same leakage rates was made. An annular expanded PTFE gasket with locally increased density is presented. Comparative tests were conducted to determine the mass of helium gas passed through the gaskets when changing the density in the sealed area to the inner diameter of the gasket. The results of the tests carried out show an improvement in the sealing ability and indicate a reduction in the mass of passed gas with the application of a lower contact stress on the seal while increasing the density in the area of the inner diameter.
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Volkov, S. S., S. A. Korolev, and L. A. Shestel. "Development of Technology and Equipment for Ultrasonic Planimetric Welding of Polyethylene Products." Proceedings of Higher Educational Institutions. Маchine Building, no. 3 (708) (March 12, 2019): 21–30. http://dx.doi.org/10.18698/0536-1044-2019-3-21-30.
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The specifics of ultrasonic planimetric welding of polyethylene containers of irregular shape filled with foodstuff are considered in this work. A planimetric wave guide that can be used for welding polyethylene containers of a large diameter (up to 120 mm) and thickness ranging from 0.4 to 1.5 mm is proposed and implemented. The issue of obtaining high-quality leak-tight weld joints with stable mechanical properties on the surface of a polyethylene container exposed to corrosive environment is resolved. Various shapes of the working surface of the planimetric wave guide are developed, making it possible to weld containers with good appearance, durability and leak-tightness. A scheme for welding containers by a planimetric wave guide with an acoustic screen is proposed. The results of studies to determine the optimal parameters for the modes of ultrasonic planimetric welding are presented. The shape, material and position of the support in relation to the planimetric wave guide are defined. The technology and equipment for ultrasonic planimetric welding of polyethylene cans of a large diameter filled with various substances and foodstuff are developed. As the result of the research, all the studied liquids are divided into three groups depending on their influence on weldability.
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Zhang, Yue Rong, and Yong Wang. "Research on Leakage Fault Diagnosis and its Simulation for Control Valve of Mixed Gas." Advanced Materials Research 181-182 (January 2011): 316–19. http://dx.doi.org/10.4028/www.scientific.net/amr.181-182.316.
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The leak tightness of control valve may be broken more easily with high flow rate, so this paper considers a control valve of mixed gas as the research object to establish a mathematical model of leakage fault on results of a study on the mechanism of leakage faults. We obtain a method of extracting fault symptom through a simulation test of fault in order to form the foundation for a system of intelligent fault diagnosis and detection (IFDD) for the control valve.
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Aulas, S., A. Hlinnik, S. Stebounov, et al. "APPLICATION OF DYE LEAK TEST FOR GASTROINTESTINAL TRACT TIGHTNESS CONTROL IN BARIATRIC SURGERY." Medical Journal, no. 2(75) (2021): 38–43. http://dx.doi.org/10.51922/1818-426x.2021.2.38.
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The problem of obesity is widespread both in the Republic of Belarus and on a global scale. So, according to the WHO, 640 million people in the world suffer from obesity [6]. In the Republic of Belarus in 2015—2016.rasprostranennost' ozhireniya sredi vzroslogo naseleniya sostavlyala 24,5 % [5, 6]. Morbidnoye ozhireniye pri IMT >40 kg/m2, ili >35 kg/m2 pri nalichii soputstvuyushchey patologii, chasto okazyvayetsya refrakternym k konservativnym the prevalence of obesity among the adult population was 24.5 % [5, 6]. Morbid obesity with a BMI >40 kg/m2, or >35 kg/m2 in the presence of concomitant pathology, is often weight loss in patients is precisely surgical intervention [2]. Among the performed bariatric operations, interventions involving gastric resection or bypass surgery prevail. Thus, in the world, the share of gastric bypass surgery on a Roux-type loop is 41.9 %, sleeve gastrectomy is 32.6 %, and the share of mini-gastric bypass is 5.0 % [6]. One of the most common complications after the listed bariatric procedures is the failure of the gastric suture line or anastomoses. After gastric sleeve gastrectomy, the incidence of this complication reaches 3.9 %, and after Roux-en-Y loop gastric bypass surgery — up to 8 % [3,7]
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Bethune, Fred, and Frank Duncklee. "EMERGENCY PIPELINE SOURCE CONTROL & REPAIR." International Oil Spill Conference Proceedings 2008, no. 1 (2008): 963–67. http://dx.doi.org/10.7901/2169-3358-2008-1-963.
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ABSTRACT Oil Spill response and clean up generally involves deployment of personnel and equipment to contain and recover product. Seldom do response teams get involved in stopping the release of product from the source of the leak. This is due to the specialized nature of the task and the risk that is involved. However the possibility of a leak with discharge pressures of several hundred pounds is a reality on most pipelines around the world. This is due to the elevation changes as it traverses hills and valleys. There are valves to protect the line and minimize spill volume, however there is still the possibility of high static pressure after the line is shut in. This paper gives a brief review of the Trans Alaska Pipeline and changes that were made in the response plan to be able to better deal with controlling the source of a spill caused by a sabotage incident in 2001. It will give a brief description of equipment that is now used to minimize the safety risk and stop a leak quickly.
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Laine, Katariina. "Pressure difference in buildings with good air-tightness: control measurements after IAQ renovations." E3S Web of Conferences 172 (2020): 05001. http://dx.doi.org/10.1051/e3sconf/202017205001.
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Improving air tightness of structures prevents uncontrolled air leaks and it can be used to solve IAQ problems in buildings, usually in combination with other renovation methods. When improving air tightness, the airflow rates of mechanical ventilation usually need to be readjusted to correspond to the changed airtightness of the envelope. In optimal situation the supply- and exhaust air volumes are balanced and the pressure differential is close to zero Pascal. The article presents several buildings (n=7, built 1986-2005, renovated 2012-2019), where air tightness has been improved and the mechanical ventilation/pressure ratio has been adjusted as a part of other IAQ renovations. The pressure difference measurements (duration 7...14 days) have been done three times after renovation: right after the renovation, after 2 years and after 5 years. In addition, the long-term functionality of the air tightness renovation has been tested at the age of 5 years both with visual survey and with a tracer-gas leak test. After 5 years, the structures had remained airtight and the sealing materials were found to be durable. Pressure ratio needed some fine adjustment in 30 % of the renovated areas, where monitoring was made right after the renovation. At the age of 5 years the pressure ratio range was acceptable (-5...+5 Pa) and stable in approximately 85 % of the renovated areas. In these airtight buildings, the major effect to the pressure difference was caused by the mechanical ventilation system. Pressure difference adjustment and stability was possible to reach in all studied buildings with careful maintenance.
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Shekarchi, M., and G. Debicki. "Comportement thermohydrique d’une paroi en béton : influence du type de béton, influence du type de chargement." Canadian Journal of Civil Engineering 34, no. 10 (2007): 1364–70. http://dx.doi.org/10.1139/l07-106.
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Tests simulating “the accidental conditions” and the “test of heating,” without the contribution of humidity, have been carried out on test equipment that we designed and fabricated in the scope of this work. The tests have been carried out on laterally sealed and insulated cylindrical specimens of ordinary or high-performance concrete having a thickness of 1.3 m. Experimental results present temperature, pressure, and moisture distribution throughout the specimens and permit to characterize the hygrothermal behaviour of a concrete wall. The different aspects of the phenomena affecting a two-phase transfer (steam, water) in a porous medium are presented. Test results show that high-performance concrete exposed to an increase in temperature presents a particular hygrothermal behaviour, because of its microstructure, that is put into evidence, notably while looking at the role of the silica fume. The migration of water is not as rapid in high-performance concrete as in ordinary concrete, which is favourable for tightness. Numerical investigation consists of adapting a heat and mass transfer model, initially built for ordinary concrete, to the high-performance concrete used in this work.Key words: hygrothermal behavior, concrete wall, ordinary concrete, high-performance concrete, leak tightness, temperature distribution, pressure distribution, moisture distribution.
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Nowoświat, Artur, Iwona Pokorska-Silva, and Mateusz Konewecki. "Tightness of Single-Family Buildings Made in Prefabricated Wood Frame Technology." Energies 14, no. 15 (2021): 4500. http://dx.doi.org/10.3390/en14154500.
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The overall objective of the study is to determine the influence of various factors on the tightness of frame-based buildings. The study presents airtightness tests—Blow Doors Tests of single-family residential buildings made in the prefabricated wood frame technology. Primarily, the impact of selected quantitative and qualitative parameters on the determined quantity n50 was defined. For that purpose, correlation analyses were performed and the statistical hypothesis stating that there is no statistically significant linear relationship between n50 (a multiplication factor of air exchange in the building effected by pressure difference of 50 Pa) and the specified qualitative and quantitative parameters was verified. The hypothesis was verified using the F and χ2 statistics. The studies demonstrated that there are no grounds to reject the research hypothesis. The obtained results formulate a comprehensive conclusion that allows to test the tightness of buildings made in the prefabricated wood frame technology and makes the tightness results independent of many features of the examined building. Ultimately, the tightness results are only dependent on the leak of the examined object. They do not depend on roof structure, wall system, floor area, cubature, number of window openings, porch.
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Liu, Wen Xue, Zhao Hua Zhi, and Gen Li Shan. "The Study on Oil Pipeline Leakage Control Device." Advanced Materials Research 211-212 (February 2011): 325–29. http://dx.doi.org/10.4028/www.scientific.net/amr.211-212.325.
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In terms of the characteristics of the oil pipeline leaks, A kind of leak control equipment was developed in which the remote control walking system, the facilities to find and locate pipe and the institutions of oil leakage recovery were designed, the explosion proof problem was solved also. The equipment can effectively raise the maintainability speed of oil pipeline leakiness, reduce an oil product pollution of leakiness to environment, lower the worker's risk and minimize the loss of the oil product leakiness.
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Werkhoven, C., E. Granneman, E. Lindow, R. de Blank, S. Verhavcrbeke, and M. Heyns. "Contamination Control of Polysilicon Gates in a Vertical Reactor Cluster Tool." Journal of the IEST 36, no. 3 (1993): 33–36. http://dx.doi.org/10.17764/jiet.2.36.3.f7k41675403409pn.
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This paper demonstrates that defect control is greatly improved when using the protected environment of a vertical reactor cluster tool comprising a preclean station. The cluster tool investigated combines the established process stability of vertical reactors with new capabilities as native oxide removal, ultraclean wafer transport, and reactors shielded from enviromental contamination. An adequate combination of clean gas usage and leak tightness makes it possible to apply HF vapor etching effectively in order to control the properties of the silicon-silicon oxide interface. For different precleaning conditions, interface and bulk contamination was measured, the sources identified, and the effect of improvements monitored. To this end, several electrical parameters were determined, including the analysis of Qhd and Ehd. Quantitative TXRF and SIMS techniques were used to correlate the results with metallic and organic contamination.
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Yalçın, Barış Can, Zakir Torun, Muhammet Balcilar, and Ahmet Koyun. "Design and servo control of a leak tightness machine working based on hydrostatic pressure aging method." Proceedings of the Institution of Mechanical Engineers, Part I: Journal of Systems and Control Engineering 230, no. 9 (2016): 932–42. http://dx.doi.org/10.1177/0959651816658813.
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Gong, Jiahao, Qifu Wang, Bingxin Liu, Huimin Zhang, and Lin Gui. "A Novel On-Chip Liquid-Metal-Enabled Microvalve." Micromachines 12, no. 9 (2021): 1051. http://dx.doi.org/10.3390/mi12091051.
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A room temperature liquid metal-based microvalve has been proposed in this work. The microvalve has the advantages of easy fabrication, high flexibility, and a low leak rate. By designing a posts array in the channel, the liquid metal can be controlled to form a deformable valve boss and block the flow path. Besides, through adjustment of the pressure applied to the liquid metal, the microvalve can perform reliable switching commands. To eliminate the problem that liquid metal is easily oxidized, which causes the microvalve to have poor repeatability, a method of electrochemical cathodic protection has been proposed, which significantly increases the number of open/close switch cycles up to 145. In addition, this microvalve overcomes the shortcomings of the traditional microvalve that requires an alignment process to assemble all the parts. When the valve is closed, no leak rate is detected at ≤320 mbar, and the leak rate is ≤0.043 μL/min at 330 mbar, which indicates it has good tightness. As an application, we also fabricate a chip that can control bubble flow based on this microvalve. Therefore, this microvalve has great prospects in the field of microfluidics.
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Krapez, Jean-Claude, Javier Sanchis Muñoz, Christophe Mazel, et al. "Multispectral Optical Remote Sensing for Water-Leak Detection." Sensors 22, no. 3 (2022): 1057. http://dx.doi.org/10.3390/s22031057.
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Water losses from water distribution means have a high environmental impact in terms of natural resource depletion (water, energy, ecosystems). This work aims to develop an optical airborne surveillance service for the detection of water leaks (WADI—Water-tightness Airborne Detection Implementation) to provide water utilities with adequate and timely information on leaks in water transportation mains outside urban areas. Firstly, a series of measurement campaigns were performed with two hyperspectral cameras and a thermal infrared camera in order to select the most appropriate wavelengths and combinations thereof for best revealing high moisture areas, which are taken as a proxy for water leakage. The Temperature-Vegetation-Index method (T-VI, also known as Triangle/Trapezoid method) was found to provide the highest contrast-to-noise ratio. This preliminary work helped select the most appropriate onboard instrumentation for two types of aerial platforms, manned (MAV) and unmanned (UAV). Afterwards, a series of measurement campaigns were performed from 2017 to 2019 in an operational environment over two water distribution networks in France and Portugal. Artificial leaks were introduced and both remote sensing platforms successfully detected them when excluding the unfavorable situations of a recent rain event or high vegetation presence. With the most recent equipment configuration, known and unknown real leaks in the overflown part of a water transportation network in Portugal have been detected. A significant number of false alarms were also observed which were due either to natural water flows (groundwater exfiltration, irrigation runoff and ponds) or to vegetation-cover variability nearby water-distribution nodes. Close interaction with the water utilities, and ancillary information like topographic factors (e.g., slope orientation), are expected to reduce the false alarm rates and improve WADI’s methodology performance.
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Golinko, V. I., A. V. Pavlychenko, S. I. Cheberiachko, and O. O. Yavorska. "Determination of tightness of the filtering half-mask adhesion to a user’s face." Naukovyi Visnyk Natsionalnoho Hirnychoho Universytetu, no. 1 (February 28, 2022): 102–6. http://dx.doi.org/10.33271/nvngu/2022-1/102.
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Purpose. To determine the correlation between adhesion tightness of filtering half-masks and anthropometric indices of employees faces. Methodology. To study tightness of the half-mask adhesion to a users face, a coefficient of NaCl aerosol test was determined in accordance with the requirements by DSTU EN 149:2017 (EN 149:2001+A1:2009, IDT). Volunteers took part in the testing selected in keeping with the parametric table divided into 12 settings along the face length and across its width. The tests were carried out using Respi and Standart respirators produced in lots by SPE Standart ltd. Findings. It has been identified that the tested filtering half-masks correspond to the standards by DSTU EN 149:2017 (EN 149:2001+A1:2009, IDT) and provide adequate protection of respiratory organs of users against harmful aerosols. It has been demonstrated that the required half-mask adhesion to a face depends upon the obturator design, half-mask geometry, and stretching force of a headband. It has been proved that employees with small faces require the instrumental verification of the preferred half-mask while selecting respiratory protective equipment. In turn, for users with large faces quality control is quite sufficient by means of any suitable method described by DSTU EN 529:2006 (EN 529:2005, IDT). Individuals with large faces have demonstrated the greatest values of the tightness coefficient of filtering half-mask adhesion. Originality. It is represented by the scientific substantiation of the tightness coefficient of filtering half-mask adhesion upon the length and width of users faces. Practical value. Mathematical expressions have been derived making it possible to calculate the tightness coefficient of the half-mask adhesion relying upon the face size. The abovementioned will help assess preliminarily protective characteristics of respirators without specific laboratory equipment.
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Koroliov, A. V., P. Y. Pavlyshyn, and I. V. Bandurko. "Experimental Research of Valve Tightness at Different Closure Forces." Nuclear and Radiation Safety, no. 4(80) (December 3, 2018): 14–17. http://dx.doi.org/10.32918/nrs.2018.4(80).03.
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Power valves are installed on almost all the pipelines of nuclear power plants performing the functions of regulation and shutting off the flow, so its failure often leads to emergencies. A particularly large number of failures is observed in motor-operated valves. Incorrect setting of the limiting clutch leads either to incomplete closure of the valve or to rod failure. Therefore, the valves are equipment of a nuclear power plant, which often falls into repair shops. Failures leading to an increase of valve leakage are especially dangerous for nuclear power plants. In this case, leakage of high-pressure valves leads to erosion of the sealing surfaces, which only increases the leakage. Thus, it is very important to determine the optimum rotational value when the valve is closed. The lack of conditions for closure force in the standards for valve leakage complicates the issue.
 A bench that allows working in the air with a pressure up to 3.5 MPa was developed on valve rod to study dependence of valve leakage on the rotational moment. Four independent parameters were measured: air pressure in front of the valve under study, closure force of the valve, volume of air loss through the valve and leakage time. A standard stop valve with a nominal diameter of 15 mm and a nominal pressure of 64 atm was used for the study.
 The determined dependence of the leakage on torque value allows recommending a gentler mode of valve closure without significantly reducing its tightness. As a result of experimental data processing, a criterial equation is obtained linking a leakage rate, pressure drop on the valve and a rotational moment value. The received criterial equation will allow defining the compromise between valve closure force and permissible leak level according to regulatory requirements. The analysis of the “leakage/rotational moment” diagram showed the possibility to reveal the damaged valves. This possibility may be used during the incoming inspection of the valves supplied to NPP, which should significantly improve the reliability of their operation.
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Voronin, K. S., E. L. Chizhevskaya, M. Yu Zemenkova, and A. V. Medvedev. "CONTROL OF GAS PIPELINE OPERATION MODES AND LEAK DETECTION USING MACHINE LEARNING." Problems of Gathering Treatment and Transportation of Oil and Oil Products, no. 6 (December 19, 2024): 194–205. https://doi.org/10.17122/ntj-oil-2024-6-194-205.
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Machine learning methods are a modern tool for managing manufacturing enterprises with a wide range of applications. In particular, when selecting operating modes of leading equipment for complex technological processes, the use of machine learning allows optimizing the use of equipment capabilities, preventing incidents and emergency situations. The paper simulates steady-state operating modes of a gas pipeline with leaks using the standard technique described in STO Gazprom 2-3.5-051-2006, as well as using the same technique but dividing the pipeline into a large number of short sections, and solving differential equations of motion and gas temperature change using the finite difference method. An analysis of the possibility of using these methods to generate a large amount of data that will allow using machine learning models to detect leaks and localize them is made.
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Nosovsky, А., A. Guryev, R. Serafyn, and O. Ivaniuk. "Features of Primary-to-Secondary Leak Accident Management Using Control Valve on HPIS Pressure Side." Nuclear and Radiation Safety, no. 2(70) (May 20, 2016): 27–31. http://dx.doi.org/10.32918/nrs.2016.2(70).06.
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The features of primary-to-secondary leak accident progression with high pressure injection system (HPIS) flow control using a control valve (CV) compared with HPIS operation without CV were analyzed within the scope of the revised accident management strategy. The management strategy for primary-to-secondary leak accident designed for symptom-oriented emergency instructions of South Ukrainian NPP unit 3 was taken as a basic strategy. The evaluation of CV efficiency applied two modes for CV (pressurizer filling mode and supporting of margin to saturation in the primary system mode), which have been used depending on the stage of the accident (before and after level recovery in pressurizer). Research was carried out for the accident progression without any equipment failures and for the accident with the failures of emergency gas removal system valve in the fully open position. In addition, the experts performed comparative calculations of the integral leak flow for the different diameters of the leak for cases with using and without using CV for HPIS. The calculation results were shown that automated work of the CV can reduce integral leak flow and ensure an adequate margin to saturation in the primary system, but comes with the self-oscillations phenomenon.
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Ponomarenko, Serhii, Іryna Potapchuk, Oleksandr Zhevzhyk, Liudmyla Kabakova, and Anna Potapchuk. "Influence of the leakage in air supply networks on the efficiency of application of pneumatic backfill equipment." Mining of Mineral Deposits 17, no. 4 (2023): 83–92. http://dx.doi.org/10.33271/mining17.04.083.
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Purpose. Determining the influence of the degree of pneumatic energy losses in the non-hermetic air supply network on the efficiency of using installed equipment in the pneumatic method of waste utilization from mining and beneficiation of minerals. To achieve this purpose, a tightness control device was developed using the method of fixed volumes. Methods. Using the molecular-kinetic theory of gases, the thermodynamics and hydrodynamics laws, the characteristics of an open thermodynamic system under excess pressure and with a degree of a capillary-type leakage are investigated. Pneumatic energy losses in the pneumatic supply pipeline are determined by the mass of compressed air leaked due to its poor tightness. Findings. The peculiarities of the tightness control of hollow products by the method of fixed volumes have been summarized. The dependences of non-production losses of compressed air and the corresponding pressure drop on the geometric characteristics of the air supply pipeline, the leakage in supply pipeline, and the time of assessing the degree of leakage have been determined. Originality. For the first time, the relationship between the parameters of compressed air in an open thermodynamic system under excess pressure during air leakage and its heat exchange with the environment has been revealed. The influence of compressed air leakage in air supply networks on the efficiency of using vibration-pneumatic machines with an annular ejector in backfill technologies has been determined. Practical implications. The research results can be used to improve the existing or develop the new technological schemes of air supply equipment that use pneumatic energy at mining and metallurgical enterprises. Minimization of energy consumption can significantly expand the scope of application of pneumatic backfilling method.
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M., Ahmad Baballe, R. Dansharif A., Muhammad N.A., and Ibrahim A. "Water Sprinkler with LPG Detection, Notification, and Control System and GSM Module." Global Journal of Research in Education & Literature 2, no. 5 (2022): 155–63. https://doi.org/10.5281/zenodo.7240107.
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This system intends to show an automatic design that can detect, alert, and regulate gas leakage by employing an exhaust fan to remove gas from the area when there is a leak and a sprinkler to put out a fire in the event of a fire break-out. An alarm is triggered, an exhaust fan moves the gas outside, and a liquid crystal display (LCD) indicates how the system is functioning despite any distortions in the event of a gas leak. The Arduino UNO serves as the system's primary controller, and the buzzer serves as a notification device. In the case of a gas leak, notifications are sent via the GSM module to the registered cellphone number. The installation of a monitoring system for gas leaks in vulnerable areas is one of the steps done to stop accidents caused by this gas leak. The system uses a gas sensor (MQ) to find liquefied petroleum gas (LPG) leaks and a buzzer to notify nearby businesses, organizations, or individuals of the problem. The appliance is designed to be used in homes where running heaters and other natural gas or LPG-powered equipment can be challenging. For businesses or sectors that rely on natural gas or LPG for their operations, the system can also be used for other things.
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Fan, Wei Jun, Lang Bin Jin, Yi Lu, and Bin Guo. "Disquisition of Performance Testing Equipment for Vacuum Booster." Applied Mechanics and Materials 103 (September 2011): 422–26. http://dx.doi.org/10.4028/www.scientific.net/amm.103.422.
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Focusing on the present situation that the domestic research of vacuum booster performance testing is still at the starting stage, combined with vacuum booster performance testing requirements, a vacuum booster performance testing equipment based on VC++ was designed and realized. It consists of two independent modules, including pneumatic control module and software module. Motion control card was used to control load deflection by pulse output. Dates of displacement sensor, force sensor and pressure sensor were real-timely collected by high-speed data acquistion card. After the analysis of industrial control computer, the vacuum booster input-output characteristic, vacuum leak-proofness are contained. Experimental data shows that the equipment can accurately and truly detect the performance of the vacuum booster. Displacement accuracy can be achieved 0.1mm, force accuracy can be achieved 1N, pressure accuracy can be achieved 0.1kPa.
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Safonov, V. S., and A. G. Grechko. "On the Issue of Choosing Criteria of Standardization of Minimum Safe Distances for Cryogenic Semi-Isothermal Liquefied Natural Gas Tanks." Occupational Safety in Industry, no. 11 (November 2024): 43–49. https://doi.org/10.24000/0409-2961-2024-11-43-49.
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Currently, the industry of small- and medium tonnage liquefied natural gas is actively developing in the Russian Federation. One of the most crucial issues is the development of the appropriate regulatory and methodological framework based on the contemporary standard and legal regulation of safety in industry. Today, there is a qualitative difference in values of minimum permissible distances for semi-isothermal tanks of liquefied natural gas as adopted in Russian and international documentations (for the Russian documentation, significantly longer distances are adopted), which clearly indicates differences in accident scenarios adopted for consideration. The study analyzes the specific conditions of the destruction of ground-based single-wall cylindrical tanks used for drainage-free storage of liquefied hydrocarbon gases under an extreme external impact accompanied by explosive boiling of a thermodynalically superheated liquid and fireball generation. Materials and technologies, quality control methods and protection systems as well as the operating conditions applied for manufacturing of semi-isothermal cryogenic tanks actually exclude a possibility of a significant spontaneous breach of leak-tightness of the internal self-supporting container, which is proved by a complete absence of incidents for a more than 50-year period of their active use both in Russia and abroad. It has been demonstrated that, unlike single-wall tanks for typical cryogenic semi-isothermal tanks of liquefied natural gas with powder-vacuum or multilayered screen-vacuum thermal insulation, in normal operation modes the conditions of thermodynamic overheating of liquefied gas cannot be reached. Therefore, when minimum safe distances from stationary ground-based cylindrical thermally insulated tanks of liquefied natural gas are standardized, the scenario of a spontaneous breach of a leak-tightness of the internal container and a spill of full volume of stored product and BLEVE effect with the generation of a fireball must be prevented.
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Yang, Bo, Jianhui Yuan, Xiaoliang Wang, Jianwei Zhang, Wei Wu, and Mingyang Xie. "Air tightness detection method in parallel for aerospace: mechanical design, system modeling and optimum control." Journal of Physics: Conference Series 2764, no. 1 (2024): 012074. http://dx.doi.org/10.1088/1742-6596/2764/1/012074.
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Abstract To address the problems of high cost, complex operation, and low efficiency of existing equipment for aerospace, a simple but efficient multichannel air tightness detection device is designed. A physical system model is constructed for the process of inflation, deflation, and inflation with leakage. The expression between the inflation/deflation rate and the valve area is obtained. Through modeling the intersection and rotation of spatial curves, the relationship between the valve area and the valve core angle is derived, and the optimal valve core angle calculation method is proposed to achieve precise rate control of inflation and deflation. Simulation experiments and numerical analysis demonstrate the superiority of the proposed system scheme, the effectiveness of the control method, as well as the accuracy of the mathematical model. For the tested object of 0.3 L, the target pressure of 400 KPa, and the inflation and deflation rate of 75 Kpa/min, by using four channels with a 10 s interval for sequential operation and adjusting valves every 60 s, the efficiency of inflation and deflation is more than 3.5 times that of a single device with a single circuit. Its performance is not much different from real-time automatic control equipment, but the economy is greatly improved.
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Zhang, Wan, Ruihao Shen, Ning Xu, Haoran Zhang, and Yongtu Liang. "Study on Optimization of Active Control Schemes for Considering Transient Processes in the Case of Pipeline Leakage." Energies 13, no. 7 (2020): 1692. http://dx.doi.org/10.3390/en13071692.
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Pipeline leakage of crude oil, refined oil or other petroleum derivatives can cause serious damage to the environment, soil, and more importantly, pose a serious threat to personal safety. The losses can be minimized to a degree by active control. Therefore, timely and effective control measures should be taken to minimize the leak volume whenever a pipeline leaks. However, the complexity of pipeline hydraulic systems makes it difficult to optimize control schemes for pipeline hydraulic devices under leak conditions, and existing studies rarely consider complex transient processes. This paper aims to establish a mixed integer linear programming model considering transient processes, hydraulic constraints, equipment constraints and flow constraints, and develop a detailed control scheme of the devices by the branch and bound algorithm. Moreover, it is the objective of the model to figure out the most optimal control plan to minimize the leakage. Experiments on a real-world liquid pipeline have proved the practicability and high reliability of the model.
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Covas, D., H. Ramos, N. Graham, and C. Maksimovic. "Application of hydraulic transients for leak detection in water supply systems." Water Supply 4, no. 5-6 (2004): 365–74. http://dx.doi.org/10.2166/ws.2004.0127.
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The current paper reports the investigation of two transient-based techniques for leak detection in water pipe systems using physical data collected in the laboratory and in quasi-field conditions. The first is the analysis of the leak reflected wave during a transient event and the second is inverse transient analysis (ITA). This was approached through the development of an inverse transient analysis tool and the collection of transient data for the testing and validation of this model. Two experimental programmes were carried out at Imperial College and in cooperation with Thames Water for the validation and testing of these techniques. Evaluation of the presence, location and size of leaks was carried out using the collected data. Transient-based techniques have been shown to be successful in the detection and location of leaks and leak location uncertainties depended on the leak size and location, flow regime and location where the transient event was generated. These leak detection methods are very promising for identifying the general area of the trunk main with leakage, and can be combined with other leak location techniques (e.g. acoustic equipment) to more precisely pinpoint the leak position. Transient-based techniques are particularly important for the diagnosis, monitoring and control of existing water supply systems, not only to detect leaks, but also to better understand the causes of pipe bursts and accidents, particularly when these are due to natural transient events.
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Afonso, Rafael M., and Luís M. Alves. "Tube Joining by a Sheet Flange Connection." Journal of Manufacturing and Materials Processing 7, no. 1 (2022): 12. http://dx.doi.org/10.3390/jmmp7010012.
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Joining of tubes to tubes by means of plastic deformation at ambient temperature allows one to solve the main limitations produced by the necessity of joining thin-walled tubes of low-to-medium diameter size made from materials that are not suitable to be welded and/or have reduced contact interfaces. The new joining solution allows one to obtain permanent mechanical joints of tubes or pipes by means of an accessory lightweight sheet metal flange subjected to annular indentation and subsequent injection of its material towards the tube walls to produce a mechanical interlock between the different elements. The sheet-flange connection can then be utilized to affix the joined tube assembly to walls or other different structures and equipment, by means of fasteners or other joining accessories attached to the sheet flange. Similar or dissimilar material combinations can be easily and safely produced while guaranteeing levels of leak-tightness within the maximum internal operating pressure of the individual tubes. A combined numerical–experimental approach is employed to identify the operative parameters as well as to explain the deformation conditions. Pull-out loads and internal fluid pressure are applied to the manufactured joint to evaluate its behavior under typical operating conditions that it may be subjected to during its service life depending on the application.
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Aleksandrovich, S. I., I. A. Shevel, A. V. Brikov, I. V. Klimova, and S. P. Priymachuk. "The Algorithm for Assessment of Consequences of Failure of a Process Pipeline by the API RP 581 3rd Edition Methodology (Level 1)." Occupational Safety in Industry, no. 5 (May 2024): 59–68. http://dx.doi.org/10.24000/0409-2961-2024-5-59-68.
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The article considers the issue of the development of an algorithm for the assessment of the consequences of failure (CoF) of the process pipeline of the gas condensate stabilization system of a hazardous production facility. The assessment of the consequences of failure is one of the main components of a risk-oriented approach to the inspection of technical devices. In accordance with the API RP 581 3rd Edition methodology, the assessment is used for equipment ranking and designed to determine the priority of inspections. Inspection, in turn, is a tool to ensure integrity, i.e., the condition of equipment that ensures its leak-tightness, which undoubtedly is a necessary condition of industrial safety. The algorithm and the detailed procedure of calculation of failure consequences consisting of 13 basic stages have been provided. As an example, the calculation of failure consequences has been conducted by the API RP 581 3rd Edition methodology (Level 1). The basic stages and the results of calculation have been compared to the calculation methodologies of technical device failure consequences effective in Russia. The results of the comparative analysis of methodologies indicate their similarity as to the application of common methods of the analysis of accident scenarios, the use of similar initial data, and the focus on the reduction of equipment failure risk. At the same time, significant differences in indices and criteria of acceptable risk level have been detected. The results of the calculation indicated the conservatism of the API 581 3rd Edition methodology (Level 1). The application of calculation of failure consequences by the API RP 581 3rd Edition methodology (Level 1) in the field of risk-oriented approach to the inspection of technical devices is possible upon its adaptation to the standards generally accepted in Russia.
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Ha, Taekyung, and Hyunjung Shin. "Vacuum Leak Detection Method Using Index Regression and Correction for Semiconductor Equipment in a Vacuum Chamber." Applied Sciences 11, no. 24 (2021): 11762. http://dx.doi.org/10.3390/app112411762.
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In semiconductor manufacturing, fault detection is an important method for monitoring equipment condition and examining the potential causes of a fault. Vacuum leakage is considered one of the major faults that can occur in semiconductor processing. An unnecessary O2 and N2 mixture, a major component of the atmosphere, creates unexpected process results and hence drops in yield. Vacuum leak detection systems that are currently available in the vacuum industry are based on helium mass spectrometers. They are used for detecting the vacuum leakage at the sole isolation condition where the chamber is fully pumped but cannot be used for in situ detection while the process is ongoing in the chamber. In this article, a chamber vacuum leak detection method named Index Regression and Correction (IRC) is presented, utilizing common data which were gathered during normal chamber operation. This method was developed by analyzing a simple list of data, such as pressure, the temperature of the chamber body, and the position of the auto pressure control (APC), to detect any leakages in the vacuum chamber. The proposed method was experimentally verified and the results showed a high accuracy of up to 97% when a vacuum leak was initiated in the chamber. The proposed method is expected to improve the process yield of the chamber by detecting even small vacuum leakages at very early stages of the process.
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Liao, Xue Bing, Qing Bin Cui, Jie Lei, and Hui Qun Shan. "Development of the Self-Propelled-Gun’s Fire Extinguisher Bottle Test Equipment Based on Pump-Valve Combined Control Scheme." Applied Mechanics and Materials 575 (June 2014): 733–37. http://dx.doi.org/10.4028/www.scientific.net/amm.575.733.
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In this paper, according to the requirements of the self-propelled-gun’s fire extinguisher bottle test technology, using variable speed metering pump technology, a variable cain pressure predictive controller is developed. The experiment is done, and experiment results show that the method can improve response speed of pump-valve combined control, and leak detection and pressure test of various types of fire extinguisher bottle is solved effectively. The trial operation proves: this test equipment is high common, high stability and high integration.
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Szelka, Michał, Mariusz Woszczyński, Jerzy Jagoda, and Paweł Kamiński. "Wireless Leak Detection System as a Way to Reduce Electricity Consumption in Ventilation Ducts." Energies 14, no. 13 (2021): 3774. http://dx.doi.org/10.3390/en14133774.
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This article presents a proposal for a wireless diagnostic system for checking the air tightness of the ventilation network. The solution is designed to increase crew safety in underground mining plants and increase the energy efficiency of the ventube ventilation system. The system is based on sensors measuring the pressure inside the ventilation duct in relation to the barometric pressure in the immediate vicinity of the duct. The flow of diagnostic data is based on a cascade transfer. The data from the first sensor are transferred successively to the last one. Based on the prior calibration of alarm thresholds in each device, the leakage or factor influencing the increase of air flow resistance is located. The article presents the genesis of the creation and discusses the principle and purpose of the system. In the following chapters, the progress of work related to testing the system in laboratory, industrial, and underground conditions at the Velenje Premogovnik mine (Slovenia) is presented. The authors analyze the test results and indicate the directions of possible further work on improving the system. The proposed leak detection system is based on a network of pressure sensors that communicate with each other to clearly pinpoint the leak location. The system has been designed for operation in underground mining plants with limited space.
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Borushchak, L. O., and B. B. Vynnychuk. "IMPROVEMENT OF THE CONSTRUCTION AND COMPUTER DEVICE INVESTIGATION FOR THE PROCESSING OF BLOWOUT-PREVENTION HARDWARE EQUIPMENT." Scientific Bulletin of Ivano-Frankivsk National Technical University of Oil and Gas, no. 1(46) (June 26, 2019): 16–24. http://dx.doi.org/10.31471/1993-9965-2019-1(46)-16-24.
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The research deals with the problem of blowout equipment test for tightness before implementation. The indicated equipment includes a stem, a system of pipelines with valves and a control system. The classic test procedure requires a mobile pumping installation that provides a pressure of 35 MPa.The cost of such tests is rather high. For testing without a pump unit, a design of a device for increased tightness has been developed, including a sealing unit of the mouth from the main column and a piston unit for creating high pressure in the test volume. Generation of a high pressure occurs by lifting the piston with a winch, mounted on the well. Disadvantages of the previously proposed design of the device are as follows. There is a considerable friction between the steel moving parts of the sealing unit. Mostly these are the pairs of a plug and a cup, and a chuck and a cone. Tightness is provided by rubber ring sleeves. Exceedence of axial load on cones causes destruction of sealing rings. The authors of the article improved the design of the sealing unit in the following way: a ball thrust bearing was seated between the ends of the pressure plug and the bottom cup and as a result the sliding friction was replaced with sliding friction. On the outer surfaces of the opening cones in contact with clamping blades, it is proposed to paste a tissue antifriction material of type Nafthlene or equivalent. The friction coefficient in such pairs is next lower order than in steel to steel pairs. The computer model of the device has been created in the Solid Works environment. The computer researches of the loading process of components of the sealing unit in the simulation program based on the finite element method were performed. As a result of the research, recommended values of the axial force, required to create a screw pair of a stem and a plug for sufficient radial axial deformation of elastic cuffs with the simultaneous non-admission of their destruction were identified. Also, the design dimensions of the pressure cups of the device were optimized, namely, the mutual axial placement of the end face, which presses on the cone, and the tapered belt, compressing the sealing ring. The determination of these parameters by an experiment is a long and expensive process.
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Hong-Xia, Luo, Zhang Hui-lan, You Jian-Ping, and Yang Sha. "A Study on the Process of Donning and Doffing Personal Protective Equipment of Health Care Workers (HCWs) in China." Prehospital and Disaster Medicine 34, s1 (2019): s169. http://dx.doi.org/10.1017/s1049023x19003868.
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Introduction:Personal protective equipment (PPE) is a necessary item in the period of unknown and high risk emerging infectious disease. It is not only the necessary requirement of strict isolation but also the last line of defense to protect medical staff.Aim:To determine the frequency and sites of contamination of personnel during the process of using Chinese PPE.Methods:Recruit 56 health care workers (HCWs) who worked in front-line clinical to test PPE issued by the Chinese Center for Disease Control for preventing Ebola virus. Eight batches of HCWs were divided to conduct simulations of contaminated PPE removal using fluorescent lotion. Then the frequency and sites of contamination of personnel were recorded after removal of contaminated PPE. The method of visual observation was used to determine contamination.Results:The frequency of easily contaminated parts included: left hand and wrist (7 times), left calf (7 times), front chest center, left and right chest (6 times each), and left abdomen (5 times). Mistakes in the process of wearing PPE included: clothing touching the ground (20.00%), N95 air mask tightness not checked (13.33%), glove air-tightness not checked (4.44%), protective clothing zipper not checked (4.44%). Mistakes in doffing PPE included: clothes touching the ground or the inner surface is polluted (20.00%), the wrong method of removing N95 mask (14.44%), touching the pollution goggles mirror with hands (12.22%), incomplete washing steps, insufficient time and frequency of hand hygiene (11.11%).Discussion:It is necessary to carry out training on PPE donning and doffing for Chinese medical workers.
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Zhu, Huan, Le Qi, and Jing Shi. "Design and Research of a Certain Type of Automatic Alarm Equipment." Journal of Engineering System 2, no. 2 (2024): 18–23. http://dx.doi.org/10.62517/jes.202402204.
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Rapid detection of oxygen leaks in pipelines is crucial to prevent catastrophic accidents. This paper presents the design of an oxygen leakage detection and alarm instrument that converts ultrasonic signals, generated by gas escaping through small holes, into audible frequencies for headset use. This instrument is particularly suitable for ensuring the airtightness of oxygen supply systems for flight crews, engine startup supplemental oxygen systems, and four-station oxygen supply equipment. The design integrates ultrasonic principles, signal processing, computer control, and anti-jamming technologies to detect even minor leaks from a distance. The modular design includes components such as ultrasonic sensors, preamplifiers, filtering circuits, and microcontrollers, ensuring high detection sensitivity and reliability. The alarm system features light and sound alerts, enhancing maintenance efficiency and safety. This modern precision testing instrument significantly improves upon traditional leak detection methods like soapy water tests.
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Mel'nik, I. V., and S. B. Tugaj. "Investigation of the throughput of the dosing device gas leak for gas discharge electron gun." Electronics and Communications 16, no. 5 (2012): 25–30. http://dx.doi.org/10.20535/2312-1807.2011.16.5.246865.
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Model of capacity of valve with conic rod, which is used for control of beam current of high voltage glow discharge electron guns, is considered. Because of complicity of valve details geometry, mathematical model of dozed item is improved by suitable choosing of empirical coefficients and its approximation. On the base of modeling and experimental data analyzing of dependence of valve exploitation characteristics from geometry parameters of dozed item is provided. Obtained results can be used for simulation of stability of operation of high voltage glow discharge electron guns inconsisting of technological equipment