• 조명전기설비학회논문지
• /
• 제26권8호
• /
• pp.102-106
• /
• 2012

This paper was carried out to survey fire hazard and improvement at the drain pump in air-conditioners. Based on the results of analysis, the proposal of electrical accidents prevention and a construction improvement are as follows. A power connection of the drain pump has two types, an electrical outlet type and direct connection type at control board of air-conditioner. The electrical outlet types need a bulletin sign or education as malfunction of the drain pump include an additional accidents, current leakage and overflowing with water on the floor from breaker trip by exterior cause and breaker off by mistake of worker. On the other hand, the direct connection types prevent a power interruption as exterior cause, but it has some trouble, cut of ground cable and without protection device. Usually it doesn't work by electrician when air-conditioner and the drain pump power work. Therefore an education or countermeasures are recommended for not electrician. Generally malfunction of the drain pump causes accumulated materials into the tank. Even though the accumulated materials lead to an overheating and burning as failure of detector occur an idling, periodic inspection of the air-conditioner filter and the drain pump tank prevent the trouble.

• 한국산학기술학회논문지
• /
• 제8권5호
• /
• pp.1192-1200
• /
• 2007

도시유역의 강우 유출은 대부분 불투수지역인 도시유역의 유출 특성상 빠른 도달시간을 갖는다. 일반적으로 도시유역에서의 강우 유출은 배수펌프장으로 집수되어 하천으로 배제된다. 그러나 설계강우를 초과하는 호우가 발생하였을 때에는 배수펌프장의 용량을 초과하여 전량 하천으로 배제하기가 어려우며 따라서, 도시유역에서의 내수침수위험성이 증가하게 된다. 현행의 배수펌프장에서의 펌프 운영 기준은 배수펌프장의 집수정 또는 유수지의 수위에 따라서 가동되도록 구성되어있다. 그러나 최근 빈번히 발생하는 국지적 집중호우는 배수펌프장의 설계용량을 초과하는 경우가 대부분이며 배수펌프장이 제어할 수 없는 강우 유출은 도시유역에서의 내수침수를 발생시킨다. 본 연구에서는 도시 지하차도에서의 실제 내수침수 사례에 대한 모의를 통하여 당시 침수 발생의 요인을 분석하고 펌프 운영에 대한 변화를 통하여 배수펌프장 강제배제시설에 대하여 평가하였다.

• International Journal of Fluid Machinery and Systems
• /
• 제5권3호
• /
• pp.109-116
• /
• 2012

Water hammer pumps can effectively use the water hammer phenomenon for water pumping. They are capable of providing an effective fluid transport method in regions without a well-developed social infrastructure. The results of experiments examining the effect of the geometric form of water hammer pumps by considering their major dimensions have been reported. However, these conventional studies have not fully evaluated pump performance in terms of pump head and flow rate, common measures of pump performance. The authors have focused on the effects on the pump performance of various geometric form factors in water hammer pumps. The previous study examined how the hydrodynamic characteristics was affected by the inner diameter ratio of the drive and lift pipes and the angle of the drive pipe, basic form factors of water hammer pumps. The previous papers also showed that the behavior of water hammer pump operation could be divided into four characteristic phases. The behavior of temporal changes in valve chamber and air chamber pressures according to the air volume in the air chamber located downstream of the lift valve was also clarified in connection with changes in water hammer pump performance. In addition, the effects on water hammer pump performance of the length of the spring attached to the drain valve and the drain pipe angle, form factors around the drain valve, were examined experimentally. This study focuses on the form of the lift valve, a major component of water hammer pumps, and examines the effects of the size of the lift valve opening area on water hammer pump performance. It also clarifies the behavior of flow in the valve chamber during water hammer pump operation.

• International Journal of Fluid Machinery and Systems
• /
• 제4권4호
• /
• pp.367-374
• /
• 2011

Water hammer pumps can effectively use the water hammer phenomenon in long-distance pipeline networks that include pumps and allow fluid transport without drive sources, such as electric motors. The results of experiments that examined the effect of the geometric form of water hammer pumps by considering their major dimensions have been reported. In addition, a paper has also been published analyzing the water hammer phenomenon numerically by using the characteristic curve method for comparison with experimental results. However, these conventional studies have not fully evaluated the pump performance in terms of pump head and flow rate, common measures indicating the performance of pumps. Therefore, as a first stage for the understanding of water hammer pump performance in comparison with the characteristics of typical turbo pumps, the previous paper experimentally examined how the hydrodynamic characteristics were affected by the inner diameter ratio of the drive and lifting pipes, the form of the air chamber, and the angle of the drive pipe. To understand the behavior of the components attached to the valve chamber and the air chamber that affects the performance of water hammer pumps, the previous study also determined the relationship between the water hammer pump performance and temporal changes in valve chamber and air chamber pressures according to the air chamber capacity. For the geometry of components attached to the drain valve, which is another major component of water hammer pumps, this study experimentally examines how the water hammer pump performance is affected by the length of the spring and the angle of the drain pipe.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2001년도 봄 학술발표회 논문집
• /
• pp.551-558
• /
• 2001

The horizontal drain method is one of methods improving reclamation ground. This method reduces consolidation time by using drained installed horizontally, and negative pressure is applied on end of these drains by vacuum pump. But, effective negative pressure still wasn't evaluated in applying this method to reclamation ground. To estimate optimum negative pressure, soil box test that make a model the in-situ by installing horizontal drains in the center is performed pressing different vacuum pressure In the laboratory, and the variations in settlement and volume of drained water through the drains during consolidation process were measured. Also, water content with distance from drain and with depth is measured after the test.

• 한국산학기술학회논문지
• /
• 제8권1호
• /
• pp.110-115
• /
• 2007

도시지역의 우수관거는 최근 발생 빈도가 높은 국지적 집중호우에 대하여 배수기능 수행이 취약한 실정이며, 특히 저지대 역류 현상에 따른 침수피해는 도시 설계 및 관거 개량사업에 있어서 반드시 해결해야할 사항이다. 본 연구에서는 강우분석을 통한 도시유출특성을 고려하여 현행 우수관거의 설계빈도에 대한 통수능력을 검토하였으며, 방류하천의 계획홍수위 영향을 고려하여 관거 내 역류 및 저지대 침수량을 분석함으로써 도시유역의 원활한 내수배제를 위한 유수지 및 펌프장의 설치 여부 및 규모 산정을 위한 기초자료를 제공하였다.

• 한국안전학회지
• /
• 제33권6호
• /
• pp.136-143
• /
• 2018

In this study, we conducted a pilot study on the multiple spurious operations (MSO) analysis in the fire probabilistic safety assessment (PSA) of domestic nuclear power plant (NPP) to identify the degree of influence of the operator actions used in the MSO mitigation strategies. The MSO scenario of the domestic reference NPP selected for this study is refueling water tank (RWT) drain down event. It could be caused by spurious operations of the containment spray system (CSS) of the reference NPP. The RWT drain down event can be stopped by the main control room (MCR) operator actions for stopping the operation of CSS pump or closing the CSS motor operated valve if the containment spray actuation signal (CSAS) is spuriously actuated. Outside the MCR, it can be stopped by operator actions for closing the CSS manual valves or motor operated valve or stopping the operation of CSS pump. The quantification result of a fire PSA model that takes into account all recovery actions for the RWT drain down event lead to risk reduction by about 95%, compared with quantification result of fire PSA model without considering them. Among the various operator actions, the recovery action for the spurious CSAS operations and the operator action for the manual valve are identified as the most important operator actions. This study quantitatively showed the extent to which the operator actions used as MSO countermeasures have affected the fire PSA quantification results. In addition, we can see the rank of importance among the operator recovery actions in quantitative terms.

• 한국자동차공학회논문집
• /
• 제17권2호
• /
• pp.132-140
• /
• 2009

Recently, the interest in the development of high efficiency Diesel engine technology using alternative fuel has been on the rise and related studies are being performed. Therefore, the DME(Dimethyl Ether), an oxygen containing fuel as an alternative fuel for light oil that can be used for diesel engines since it generates very little smoke. But it is unavoidable that the modification of a fuel supply system in an engine to application of the DME fuel because of DME fuel properties. So, in this study, a DME high pressure pump for a common-rail fuel supply system has been composed and the test results of the pump have been presented. As the results of the tests, it is confirmed that DME pump inlet pressure, pump speed and common-rail pressure effects on the volumetric efficiencies of the pump. Finally, it is defined that the optimum plunger volume of a DME pump has to be extended to the minimum 150% compared to a Diesel pump plunger volume considering DME fuel properties and volumetric efficiencies characteristics at same specifications of the high pressure pump.

• 한국지반공학회지:지반
• /
• 제13권2호
• /
• pp.39-54
• /
• 1997

연약지반 개량공법으로 국내에서 생산된 플라스틱 보드 드레인(PBD)이 많이 사용되고 있으나 이들에 대한 물리적 성질 및 배수성능의 검증이 미약한 실정이다. 또한 PBD의 웰 레지스턴스(well resistance)에 크게 영향을 미치는 공기(기포)의 영향에 대한 인식이 부족하다고 판단된다. 따라서 본 연구에서는 대형 실험장치를 이용하여 먼저 국산 PBD를 중심으로 물리적 성질 및 배수성능 시험을 실시하여 제품의 질적 수준을 규명하고 대표적인 국외제품과 비교했다. 아울러 PBD재의 꺾임 부분에 누적된 공기(기포)가 통수능력에 지장을 초래하는 것을 재확인하였으며 현장에서 적용할 수 있는 진공펌프를 이용하여 필기(기포)를 제거시키므로써 통수능력의 회복이 가능하다는 것을 나타냈다.

• 한국산학기술학회:학술대회논문집
• /
• 한국산학기술학회 2011년도 춘계학술논문집 1부
• /
• pp.347-350
• /
• 2011

본 논문에서는 습식식각 설비의 Process 동작 간에 발생되는 설비의 비 가동 시간을 최소화하여 Throughput을 향상시키기 위하여 Monitoring 한 결과 Recipe 변경, 액 교환 발생, Tact 변경 등의 공정간 조건에 따라 대기시간이 발생(생산 지연시간 발생) 하는 것을 확인 하고 이를 개선하기 위한 연구이다. 연구 방법으로, Recipe Data 적용 시점을 약액 구간 처리 완료 시점에서 후속 기판이 대기하지 않고 연속 투입을 실시, Chamber Drain과 약액 Tank 전환이 동시에 이루어지고 액 교환 동작 중 Pump Spray의 연속성을 유지하는 무정지 액 교환 Sequence 적용, Tact 적용 시점을 전 기판 배출 확인 후 실시하는 것을 약액 구간 처리 완료 후 적용의 3가지 방법을 6시그마의 DMAIC 기법을 활용하였다. 연구 결과 개선 전 비 가동 시간이 설비 대당 1일 28분 시그마 Level 3.40 이었던 것을 개선 후 설비 대당 1일 17분 시그마 Level 5.3 으로 개선됨을 확인 할 수 있다.