• Journal of the Korean Institute of Gas
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• v.21 no.6
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• pp.15-22
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• 2017

The pressure safety valve is very important device for securing the safety in the facilities which is operated by high pressure gases. The performance test should be periodically inspected by relate law because the failure of pressure safety valves might be main causes of serious accidents in the industrial fields. Shop test is mainly use for inspecting the performance test of pressure safety valves but the test method is not to be a solution for securing the safety. So, the development of alternative method is required. In this paper, there is a limit to securing the safety if the performance test is with just shop test. The limitation is checked from analysis result based on performance test results of pressure safety valves. The necessity for introducing the in-service test is reviewed to surmount the limitation. As a result, in-service test method should be developed and introduced to improve the inspection efficiency and economical loss. Also, it can be reduce the risk level.

• The Journal of the Acoustical Society of Korea
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• v.16 no.1E
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• pp.9-14
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• 1997

Check valves used in industrial and Nuclear Power Plant safety systems are susceptible to failure modes generally associated with wear of internal parts. Specifically, hinge pins, disc studs, pistons, and other mechanical parts may degrade over time, and in some cases, may which might produce a disabling event leading to plant or process shutdown. The primary diagnostic technique in the past has been to disassemble the valves. This procedure is costly, time consuming, and in the nuclear industry, it can lead to radiation exposure in some situations. Additionally repair and reassembly of a valve does not ensure proper operation. Non-intrusive diagnostic technologies including acoustics and magnetics with a digital signal analysis allow to evaluate check valve performance without a disassembly and is able to help the user detect degraded valve conditions.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.355-356
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• 2015

LS산전은 전기적 트리거 방식의 사이리스터(electrical-triggered thyristor)를 이용한 Static Var Compensator(이하 SVC) 개발에 성공했다. 개발된 SVC는 ${\pm}100MVar$ 급으로 과전압에 대한 자체 보호 기능을 내장하고 있으며 LS산전표준과 IEC 규격에 따라 성능이 검증되었다. 본 논문에서는 SVC 시스템의 핵심 구성품인 Thyristor Controlled Reactor (이하 TCR) / Thyristor Switched Capacitor (이하 TSC) Valve 개발 시험의 일부로 진행한 절연 시험에 대해 상세히 소개하고자 한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.446-452
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• 2016

Recently, heat resistant super alloys (which are wear-resistant, corrosion-resistant, and heat-resistant), have been used as the basic structural material in offshore and petrochemical plants. On the other hand, making valves from very expensive, high heat-resistant alloys increases the production cost and decreases its market competitiveness. To solve these problems, the technique of overlaying only those that flow on the fluid has been used as an effective method. Nevertheless, because the former technique of overlaying the ball is performed manually, it takes too much time and perfect welding is difficult to perform. To solve this problem, this study developed a robot automation system that can make uniformly overlay welding of the ball for ball-valves. The system consists of a 6-axis welding robot with a welding torch and additional 2 axes for the rotation of positioner, the controller, and a robot path OLP (Off-Line Programming). The CAD drawing data was entered in the Off-line program to obtain the robot teaching point and drive source. Overlay welding paths were implemented using Matlab. Through an automated overlaying system that implemented the OLP, the productivity rose 2.58 times, as the amount of time required for work decreased from 88 hours to 41 hours.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.12
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• pp.5704-5708
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• 2012

In this paper, the algorithm to determine the optimal condition of traverse grinding is proposed by using differential evolution algorithm(DEA). The cost function to determine the optimal grinding condition is designed with considering process cost, production rate, surface roughness. Also, the constraint conditions for grinding such as thermal damage effect, machine tool stiffness, wear parameter of grinding wheel, surface roughness are considered. The algorithm is implemented with LabView software which is widely used at the industrial field. The performance of proposed algorithm is verified by comparing with the result of genetic algorithm(GA) through computer simulation.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.23 no.55
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• pp.51-71
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• 2000

A case of company manufacturing industrial valves is studied. To survive the fierce competition in the low-volume, high-complexity production environment, the company needs accurate information on the cost of its products. Current cost accounting system which allocates production costs based on the weights of intermediates and final products cannot provide accurate cost information that managers really need. Data on the company's cost structure and production processes were reviewed and managers were interviewed before problems with the current costing system were identified. Activity-based costing (ABC) system as well as an improved traditional costing system is considered to replace the current system. A prototype of ABC system is developed to better represent the relationships among the cost drivers, activities, and products.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.1
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• pp.7-12
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• 2013

This paper proposed the optimal algorithm of grinding system and the method to realize it. The optimal function was proposed in order to design the optimal grinding process. DE(Differential Evolution) algorithm was used to obtain the selective optimal function. The realization of algorithm was implemented by LabView software used widely at industrial field and the proposed algorithm was verified for through computer simulation. The result of the proposed algorithm can be used for the guide line of the grinding process.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.2
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• pp.77-83
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• 2012

Effect of valve conductance on performance of vacuum system was simulated for optimum design of vacuum system. In this investigation, the feasibility of modeling mechanism for VacSimMulti simulator was proposed. Application specific design of vacuum system is required to meet the particular process conditions for various industrial implementations of vacuum equipments. Geometry and length, diameter of vacuum valve were modeled as simulation modeling variables for conductance effects. Series vacuum system was modeled and simulated with varied dimensions and structures of exhaust valves. Variation of valve diameter showed the more significant effects on vacuum characteristics than that of pipeline length variations. It was also observed that the aperture structure of valve had the superior vacuum characteristics among the modeled systems.

• Journal of the Korean Society of Safety
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• v.21 no.5 s.77
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• pp.12-16
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• 2006

This paper deals with the noise evaluation and noise reduction of a reciprocating air-compressor. The reciprocating air-compressor is widely used in the small and medium sized industrial firms, many employees exposed and irritated by their noise in the workplace. Thus, appropriate noise control actions should be taken to prevent hearing loss due to the its noise exposure. Lead-wrapping techniques are employed to identify the contribution of principal noise sources which are generally known to be motor, belts, suction valves, discharge valves, moving parts, and flow-induced noise caused by edges or discontinuities along the flow path including expansions, contractions, junctions and bends. As a result, the main noise sources of the air-compressor are categorized by the suction and discharge noise, valve noise, and compressed air tank noise. Based on the investigations, mufflers are designed to reduce both the suction and discharge noise and the compressed-air tank noise. Instead of the conventional valve plate, polyethylene resin is used the reduction of valve impact noise. In addition, attempts are made to reduce the valve noise propagation to the cylinder head and the compressor tank by using the insulation casings. As a result of the countermeasure plans, a noise reduction up to 10dB(A) could be achieved for the air-compressor.

• The KSFM Journal of Fluid Machinery
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• v.11 no.2
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• pp.13-19
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• 2008

Butterfly valves are widely used as control valves for industrial process. For the definition of optimum configuration of the valve, wide range of related studies has been actively conducted in the case of working fluids of water or air under the normal temperature. Recently, internal flow and performance characteristics of cryogenic butterfly valve for LNG carrier take a growing interest in the field of research and development. Therefore, present study is aimed to investigate the internal flow and performance characteristics of the cryogenic butterfly valve because the study result for the valve can be hardly found at present. Part 1 of this paper describes the study result of a butterfly valve model under the condition of the normal temperature. Succeeding Part 2 of this paper will describe the internal flow characteristics of a cryogenic butterfly valve for LNG carrier. The results of Part 1 show that pressure loss coefficients and flow rate coefficients obtained by the present experiment and CFD analysis agree well each other. Moreover, internal flow visualization for the valve by CFD analysis and PIV measurement have revealed complicated flow patterns of the internal flow field in detail.