• 한국재난정보학회 논문집
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• 제16권1호
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• pp.144-154
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• 2020

연구목적: 본 논문은 밸브의 누수 상태를 확인하기 위한 모니터링 시스템을 위하여 개발된 스마트 볼트의 적용성에 대한 기초 연구이다. 연구방법: 스마트 볼트에 내장된 변형률 센서와 가속도 센서를 이용하여 모의 누수 탐지 실험을 실시하였다. 연구결과: 스마트 볼트는 볼트 조임토크 기준에 부합하였으며 허용인장응력 범위 내에서 거동을 하여 상수도 체결부 적용에 부합되는 것으로 나타났다. 그리고 모의 누수 실험결과 밸브 누수 지점에선 60Hz 대역의 누수 신호가 탐지 되었으며, 메인관 누수에서는 상대적으로 고주파수 대역의 누수 신호도 탐지되었다. 결론: 모의 배관이 구속되지 않은 상태에서 전체적으로 연성진동이 이뤄진 것으로 보인다. 스마트 볼트를 통해 밸브 누수 신호의 감지에 대한 가능성을 확인하였다.

• 반도체디스플레이기술학회지
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• 제20권2호
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• pp.14-18
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• 2021

Electric Vehicle industry requires high technologies to stabilize apparatuses for the Coolant heater manufacturing. Vibrations of Leak Machine are one of the most critical factors for causing delivered of the defective product or poor inspection, which are the main reasons of the defects. In this study, the structure of the Leak Machine was analyzed through the experiment and the computer simulation to investigate the main reasons of the vibrations, and further to alter the design for the improved stability. And that design alterations were applied to the machine to identify the effects of those alterations. The result of the study shows that design alterations of the Leak Machine can effectively suppress about 97.8% of the vibrations, and further can improving the Inspection precision of the Coolant heater.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2019년도 춘계학술대회
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• pp.406-408
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• 2019

자동차에 사용되는 전동식 워터펌프에 적용되는 모터는 CANNED TYPE의 모터 구조이다. 모터의 구동 부품인 로터는 플라스틱 사출물의 격벽 구조 내에 위치하며, 부동액에 침수되어 있는 상태로 회전을 하게 된다. 플라스틱 사출물 격벽 구조 외부에 Stator가 위치되어 Rotor가 회전이 가능하도록 한다. Rotor의 구성은 Magnet와 Core, Shaft로 구성되며, Magnet와 Core의 경우 부품 특성상 수분 침투에 부식되는 재질이기 때문에 부품의 기밀 유지는 매우 중요하다. 차량에 장착된 상태에서는 120도의 환경조건에서 구동이 가능하여야 하며, 내부압력이 1 Bar 이상의 압력에도 누수가 없어야 한다. 본 논문에서는 이 조건을 만족하여 개발된 전동식 워터펌프의 불량을 검사하기 위하여 헬륨을 이용한 Leak 검사 자동화 시스템을 설계 및 구현하였다.

• 한국산업보건학회지
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• 제4권2호
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• pp.180-188
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• 1994

This study was designed to investigate qualitatively whether respirators now being used in workplaces tit workers iflfaces well or not. Leak sites were determined after exposing the subjects to fluorescent aerosol and were analyzed by gender, brand and manufacturing nation. The results were as follows ; 1. Among those leak sites which were classified into four areas(nose, cheek, lip and chin), test aerosol was mostly deposited on the nose and the cheek areas. 2. The mean number of leak sites observed from the female subjects were 2.3 while the number were 2.2 from the male subjects. The most frequently observed leak site was nose and followed by chin, lip and cheek in descending order of frequency. 3. Among different brands of respirators, different leak sites were observed. Test subjects wearing the Sand N brands were more heavily exposed than those of wearing the D and M brands. 4. No significant difference of the number of leak sites were found between Korean-made and American-made masks. However, the most frequent leak site observed for the Korean-made ones was the nose area while it was the chin area for the American-made ones. 5. Analyses of 97 leak sites by shape showed that 27(27.8%) were point types, 54(55.7%) diffuse types and 16(16.5%) streamline types. 6. Test subjects indicated that the facepieces of Korean-made respirators were harder and smaller in size than those of American-made one. The most comfortable respirator selected was the respirator by the N Co. and the most uncomfortable one was the respirator by the D Co. This study suggests that many half-mask respirators now being used in the workplaces may not fit to workers well. Therefore, when selecting respirators, employers are advised to test respirators if they fit to workers well. And manufacturers are recommended to produce effective and comfortable respirators tested qualitatively and quantitatively not only in the laboratory but also in the field.

• 한국가스학회지
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• 제20권5호
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• pp.40-49
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• 2016

지하 매설배관을 이용한 유체 수송 중 임의의 배관 위치에서 누설이 발생할 경우 육안 식별의 어려움으로 진동 센서 등을 이용하여 누설 위치를 탐지한다. 이러한 누설 위치 검출 시스템은 물과 같은 비 압축성 유체를 대상으로 센서 간의 신호 도달 시간차와 음파의 전파속도를 이용하여 검출하고 있다. 본 논문에서는 가스와 같은 압축성 유체의 누설 검출을 위한 시스템을 개발하고자 기존 검출 방법을 검토하고, 온도와 압력을 고려한 압축성 유체의 전파속도 식을 개선하고 압축 공기를 이용한 실험 장치를 구축하여 실험 수행을 통해 검증하였다. 검증 결과 매설배관 내 압축성 유체의 누설 위치 검출이 가능함을 확인하였으며, 가스 수송용 매설배관 내 누설 위치 검출 시스템 개발에 적용 가능함을 확인하였다.

• 대한임상독성학회지
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• 제4권2호
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• pp.122-127
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• 2006

Purpose: It is not easy to detect carbon monoxide (CO) leakage, and CO-intoxicated patients do not show a specific set of symptoms. The aims of this study are to clinically evaluate patients with CO gas intoxication from a CO leak at an underground shopping center, and to discuss the establishment of a disaster prevention plan. Methods: A total of 51 patients intoxicated by CO gas exposure in a gas disaster at a underground shopping center in Seoul on September 8, 2006 were enrolled in this study, and the patients' medical records were retrospectively reviewed. Results: The mean patient age was $29.4{\pm}6.3$. The initial mean COHb level was $14.98{\pm}6.97%$. The number of patients with COHb greater than 25% was three, and six patients experienced a syncopal attack. Only one patient-was treated with hyperbaric oxygen therapy. However, none of the patients complained of severe neurologic or cardiovascular symptoms. Conclusion: The symptoms of CO intoxication are non-specific and difficult to define, and the detection of CO leak-age is difficult. Thus, workplaces should be equipped with leakage sensors and automatic alarm systems and should have develop disaster prevention plans.

• 비파괴검사학회지
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• 제28권6호
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• pp.469-476
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• 2008

Condition based maintenance(CBM) for the preventive diagnosis of important equipments related to safety or accident in power plant is essential by using the suitable methods based on actual power plant conditions. To improve the reliability and accuracy of the measured value at the minute leak situation, and also to monitor continuously internal leak condition of power plant valve, the development of a diagnosis and monitoring technique using multi-measuring method should be performed urgently. This study was conducted to estimate the feasibility of multi-measuring method using three different methods such as acoustic emission(AE) method, thermal image measurement and temperature difference$({\Delta}T)$ measurement that are applicable to internal leak diagnosis for the power plant valve. From the experimental results, it was suggested that the multi-measuring method could be an effective way to precisely diagnose and evaluate internal leak situation of valve.

• Nuclear Engineering and Technology
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• 제51권1호
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• pp.155-162
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• 2019

To reduce the secondary damage caused by leakage accidents in plant piping systems, a constant surveillance system is necessary. To ensure leaks are promptly addressed, the surveillance system should be able to detect not only the leak itself, but also the location of the leak. Recently, research to develop new methods has been conducted using cameras to detect leakage and to estimate the location of leakage. However, existing methods solely estimate whether a leak exists or not, or only provide two-dimensional coordinates of the leakage location. In this paper, a method using multiple cameras to detect leakage and estimate the three-dimensional coordinates of the leakage location is presented. Leakage is detected by each camera using MADI(Moving Average Differential Image) and histogram analysis. The two-dimensional leakage location is estimated using the detected leakage area. The three-dimensional leakage location is subsequently estimated based on the two-dimensional leakage location. To achieve this, the coordinates (x, z) for the leakage are calculated for a horizontal section (XZ plane) in the monitoring area. Then, the y-coordinate of leakage is calculated using a vertical section from each camera. The method proposed in this paper could accurately estimate the three-dimensional location of a leak using multiple cameras.

• Nuclear Engineering and Technology
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• 제30권5호
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• pp.403-415
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• 1998

The CANDU 6 reactor assembly consists of an array of 380 pressure tubes, which are installed horizontally in a large cylindrical vessel, the Calandria, containing the low pressure heavy water moderator. The pressure tube is located inside the calandria tube and the annulus between these tubes, which forms a closed loop with $CO_2$ gas recirculating, is called the Annulus Gas System(AGS). It is designed to give an alarm to the operator even for a small pressure tube leak by a very sensitive dew point meter so that he can take a preventive action for the pressure tube rupture incident. To judge whether the operator action time is enough or not in the design of Wolsong 2,3 & 4, the Leak Before Break(LBB) assessment is required for the analysis of the pressure tube failure accident. In order to provide the required data for the LBB assessment of Wolsong Units 2, 3, 4, a series of leak detection capability tests was performed by injecting controlled rates of heavy water vapour. The data of increased dew point and rates of rise were measured to determine the alarm set point for the dew point rate of rise of Wolsong Unit 2. It was found that the response of the dew point depends on the moisture injection rate, $CO_2$ gas flow rate and the leak location. The test showed that CANDU 6 AGS can detect the very small leaks less than few g/hr and dew point rate of rise alarm can be the most reliable alarm signal to warn the operator. Considering the present results, the first response time of dew point to the AGS $CO_2$ flow rate is approximated.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2019년도 춘계학술논문요약집
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• pp.341-342
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• 2019