• Journal of Ocean Engineering and Technology
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• v.30 no.2
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• pp.100-108
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• 2016

A high-pressure ball valve was developed, and both the structural strength and sealing performance were assessed based on a nonlinear finite element analysis. Different parts were modeled with solid elements and assembled, taking into account both contact and sliding effects. Three different loading scenarios were analyzed, including a high-pressure closure test and fire and shell test conditions. The structural safety of each part was checked under each loading condition, and the sealing performance was also investigated to validate the performance of the valve.

• Journal of Ocean Engineering and Technology
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• v.28 no.2
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• pp.160-166
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• 2014

Because of industrial development, industrial facilities are becoming more complex and diversified. Plant industries are focused on productivity improvement, cost reduction, and product uniformity by simplifying production processes using automated control. Furthermore, plant industries require higher pressures and temperatures to improve energy efficiency. For this reason, the valves used in plants are operated under harsh conditions. Globe valves and gate valves are mainly used for high pressure these days. However, these valves have various problems, including low maintainability and high cost, due to structural problems. Therefore, butterfly and ball valve applications are increasing in industrial plants. This paper suggests a quadruple-offset butterfly valve that is applicable to bi-direction use, and the principle design parameters are suggested. The selected design parameters are an eccentric flange center line and shaft centerline(Offset 1), an eccentric seat centerline and disc shaft centerline(Offset 2), the angle between the flange centerline and seat wedge angle(Offset 3), the angle between the vertical direction of the disc shaft centerline and seat centerline(Offset 4), and the seat engagement angle. To analyze the interaction effect of the design parameters, ANOM and ANOVA were performed with an orthogonal array. The parameters were found to have effects in the following order: Offset 2, Offset 1, engagement angle, Offset 3, and Offset 4. The interaction between the parameters was insignificant.

• Journal of Biosystems Engineering
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• v.22 no.1
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• pp.41-48
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• 1997

A nondestructive quality inspection technique using acoustic impulse response method was studied to investigate the feasibility of egg shell inspection. An experimental system was built to generate impact force, to measure the response signal and to analyze the frequency spectrum. This system includes an impulse generating unit, an egg holding seat, a microphone with preamplifier, and a digital oscilloscope connected to Personal Computer by RS-232C interface. The factors such as impulse generating method, egg holding method, and sensor location were evaluated by analyzing the power spectrum density of the measured signal. The results obtained are summarized as follows : 1. From the sampled eggs, the proper conditions for detecting damaged eggs were found as followings; ceramic for the impact ball material, rubber for egg seat material, 20 degrees for an impact angle of pendulum, 10mm for the distance between egg and sensor, the sharp side for impacting part, and 180 degrees for the location of sensor. 2. Examination of the Fourier transformed analysis in beth normal and damaged eggs revealed that those factors such as the resonant frequency, a number of peak frequencies and the magnitude of power spectrum were important to detect damaged eggs.

• Korean Journal of Metals and Materials
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• v.50 no.6
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• pp.445-448
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• 2012

We studied the effect of temperature and reaction time by investigating the various temperatures and reaction times in the reduction of molybdenum oxide ($MoO_3$) to molybdenum (Mo) powder in hydrogen gas. We also studied the effect of the reaction of reduction according to the various hydrogen gas flow rates. We surveyed the reduction from molybdenum oxide to molybdenum powder in hydrogen gas and checked two temperature ranges, one from $400^{\circ}C$ to $600^{\circ}C$ and the other from $700^{\circ}C$ to $900^{\circ}C$. We found that the reaction ratio of molybdenum oxide increased with an increasing temperature and also increased with an increasing reaction time, but hydrogen gas did not influence the reduction ratio of molybdenum oxide. We examined molybdenum powders fabricated by ball milling for two hours, using with X-ray diffraction (XRD) and a scanning electron microscopy (SEM).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.2
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• pp.373-380
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• 2020

A valve product can be over-designed or too heavy. Finite element analysis was performed using ANSYS for two and three-dimensional ball valve models, and the ball weight was reduced by optimization within the allowable design criteria. The ball is structurally safe according to the computed stress values, which are within the material's admissible stress. The weight was reduced by about 22%, and the structural safety factor was 1.25. The structural safety of the seat insert and ring, which are used to prevent leakage, was confirmed through finite element analysis. It is shown that the two-dimensional analysis can result in similar values to the three-dimensional analysis for the axisymmetric structure. The redesign of the valve is not included in the results since such changes require a whole new design process, including all valve components.

• International Journal of Fluid Machinery and Systems
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• v.10 no.1
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• pp.40-46
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• 2017

Small valves including ball valves, gate valves and butterfly valves have been adopted in the fields of steam power generation, petrochemical industry, carriers, and oil tankers. Butterfly valves have normally been applied to fields where in narrow places installing the existing valves such as gate valves and ball valves have proven difficult due to the surrounding area and the heavier of these valves. Butterfly valves are used to control the mass flow of the piping system under low pressure by rotating the circular disk installed inside. The butterfly valve is benefitted by having simpler structure in which the flow is controlled by rotating the disc circular plate along the center axis, whereas the weight of the valve is light compared to the gate valve and ball valve above-mentioned, as there is no additional bracket supporting the valve body. The manufacturing company needs to acquire the performance and life test equipment, in the case of adopting the improving factors to detect leakage and damage on the seat of the valve disc. However, small companies, which are manufacturing the industrial valves, normally sell their products without the life test, which is the reliability test and environment test, because of financial and manpower problems. Furthermore, the failure mode analysis of the products failed in the field is likewise problematic as there is no system collecting the failure data on sites for analyzing the failures of valves. The analyzing and researching process is not arranged systematically because of the financial problem. Therefore this study firstly tried to obtain information about the failure data from the sites, analyzed the failure mode based on the field data collected from the customers, and then obtained field data using measuring equipment. Secondly, we designed and manufactured the performance and life test equipment which also have the real time monitoring system with the naked eye for the butterfly valves. The concept of this equipment can also be adopted by other valves, such as the ball valve, gate valve, and various others. It can be applied to variously sized valves, ranging from 25 mm to large sized valves exceeding 3000 mm. Finally, this study carries out the life test with square wave pressure, using performance and life test equipment. The performance found out that the failures from the real time monitoring system were good. The results of this study can be expanded to the other valves like ball valves, gate valves, and control valves to find out the failure mode using the real time monitoring system for durability and performance tests.

• 한국가스학회:학술대회논문집
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• 2006.11a
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• pp.245-250
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• 2006

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.6
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• pp.37-45
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• 2014

Ball valves are used as a key element in the process industries. The industrial development of valves has increased steadily, but continued improvement requires high design reliability and long service life. Currently, the development of high performance valves is not easy because of the lack of relevant technology in Korea. Valves are being imported at a level of up to 58 percent of the domestic market, which represents a value of almost 7 million US dollars. Therefore, in this work, the improvement of the design and performance of industrial valves has been studied in an attempt to achieve valves that will have longer service life and better output during operation. The structural stability was evaluated using the ANSYS FSI (Fluid-Structural Interaction) module. Moreover, to obtain maximum product reliability, torque analysis simulation was performed to compare and experimental results. The simulation results were used to predict the change in torque by changes in shape, thereby reducing the time and cost of manufacturing a number of prototypes for experimental validation.

• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.357-362
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• 2008

This study have goal with reverse engineering for petrochemistry of high pressure ball valve for localization. Ball valve for development accomplished with flow analysis based on provision of ANSI B16.34, ANSI B16.10, ANSI B16.25 In order to localize the petrochemistry high pressure control valve. Numerical simulation using CFD(Computational Fluid Dynamic) in order to predict a mass flow rate and a flow coefficient form flow dynamic point of view. The working fluid assumed the water($H_2O$). The valve inlet and outlet setup a pressure boundary condition. The outlet pressure was fixed by atmospheric pressure and calculated inlet velocity 5m/s. CFD solver used STAR-CCM+ which is commercial code. The result shows change of mass flow rate according to opening and closing angle of valve. Flow decrease observed open valve that equal percentage flow paten which is general inclination of ball valve. The structural analysis used ANSYS which is a commercial code. Stress analysis result of internal pressure in valve showed lower than yield strength. This is expect to need more detail design and verification for stem and seat structure.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.5
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• pp.961-967
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• 2007

Automatic water feeding system for chickens is the one of the most important devices at poultry farms. Chickens drink water directly from a water feeder nipple of the automatic water feeder. Check valve inside the water feeder nipple is open when they drink water and is closed otherwise. There are two types of nipples. One is the piston nipple, and the other is the ball nipple. Because the nipple stick in the ball nipple can move freely, the sloping mechanism of the ball nipple works well. but it has complicated mechanism. On the other hand, the piston nipple has very simple structure, but its movement is limited so it can move only up-and-down. To overcome those limitation, the piston nipple with sphere valve seat face (sphere face piston nipple) has been developed and is just distributed at domestic markets. The experimental performance test of the commercialized sphere piston nipple has been conducted, and compared with the performance of the ball nipple and the piston nipple which are domestic products. As the result, sphere piston nipple shows excellent performance compared to that of the piston nipple but its performance is similar to ball type nipple.