• 제목/요약/키워드: Pipe insulation

검색결과 95건 처리시간 0.027초

국내 석면 고형시료 중 석면의 종류 및 함유량에 관한 연구 (A Study on Types and Contents of Asbestos in Bulk Samples)

  • 최호춘;안선희;홍좌령;전봉환;이용필;박정일
    • 한국산업보건학회지
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    • 제21권4호
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    • pp.201-208
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    • 2011
  • Objectives: According to the compliance of the asbestos-related regulation, every building has to be inspected for asbestos presence before its abatement work. This study was performed for identifying the types and contents of asbestos in building bulk samples. Materials and Methods: Bulk samples were collected during the asbestos inspection in 2010. We grouped the bulk samples into the regulated asbestos containing materials(RACM), presumed asbestos containing materials(PACM), and construction products. Additionally, the types of asbestos in all bulk samples were identified by polarization microscopy(PLM). Results: The RACMs were from building, house, pipe and facility. The RACMs were found mainly building (72.1%) and house (93.7%). The contents of chrysotile in building, house and facility were 66.9% (1-90%), 89.7% (2-90%) and 11.0% (2-90%), respectively. PACMs were surfacing material, thermal system insulation (TSI), and miscellaneous material. The miscellaneous materials that showed a high detection rate (79.2%) were ceiling, roofing and wall materials. Among them, the roofing materials had high chrysotile content(9.7%, 2-21%), followed by wall (8.7%, 2-21%) and ceiling (3.4%, 1-17%). In the construction products, asbestos was found mainly in slate (92.6%, 2-21%), including chrysotile. The slate had high asbestos content (9.7%, 2-21%), followed by cement flat board (8.7%, 2-19%) and textile (3.4%, 1-17%) Conclusions: Utilizing these results, it would be contributed to construct a useful ACM database and prevent from asbestos exposure to workers in the asbestos abatement and maintenance works.

감마선을 이용한 단열배관의 실시간 두께측정시스템 개발 (Development of Real-Time Thickness Measuring System for Insulated Pipeline Using Gamma-ray)

  • 장지훈;김병주;김기동;조경식
    • 비파괴검사학회지
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    • 제22권5호
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    • pp.500-507
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    • 2002
  • 본 연구에서는 감마선과 섬광체 및 광 다이오드로 구성된 64 채널의 선형 디텍터 어레이를 이용하여 보온재로 싸인 배관의 두께를 실시간으로 측정하는 시스템을 개발하였다. 본 측정시스템은 감마선원으로 Ir-192를 사용하였으며, 디텍터는 BGO 섬광체와 광다이오드로 구성하였다. Ir-192 방사선원은 배관의 한쪽 편에, 그리고 디텍터 어레이는 배관을 중심으로 그 반대편에 위치하며 컴퓨터로 제어되는 주행 시스템에 실려 배관을 따라 이송되는 동안 배관과 단열재를 투과한 방사선의 강도는 각 디텍터에서 측정된다. 측정된 디텍터 어레이의 출력은 증폭기에서 증폭된 후 케이블에 의해 컴퓨터로 전송되며 주행시스템이 진행하는 동안 컴퓨터는 수집된 신호를 분석 및 계산하여 실제의 두께를 나타내며 주사간격을 1mm로 할 경우의 최대 측정속도는 분당 120cm이다.

가스히터 보수주기 결정을 위한 히터내부 열전달 매체액 결빙현상 가시화에 관한 연구 (A Study on the Visualization of Ice-formation Phenomena of Bath Water to Decide Maintenance Period of Gas Heater)

  • 이정환;하종만;성원모
    • 한국가스학회지
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    • 제5권3호
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    • pp.1-8
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    • 2001
  • 본 연구는 한국가스공사에서 운영중인 천연가스 공급관리소의 가스히터를 대상으로 겨울철 히터 가동 중단시, 가스히터 내부의 열전달 매체액 (Bath Water)이 빙점에 도달하는 시간을 계산하여 보수주기에 대한 결정 및 동파 취약 부위에 대한 영향을 판단하기 위해 가스히터의 체적을 고려한 비선형 3차원 전산모사를 수행하였다. 이용된 시뮬레이터는 미국 FLUENT사의 FLUENT V 5.0으로서 열유체 유동해석 범용 Code이다. 본 문제는 열전도에 관한 문제로 에너지 방정식을 푸는 방식으로 진행되지만 가스히터의 체적을 고려한 3차원 계산을 수행하기 위해 현장의 가스히터 형상 및 축적을 거의 유사하게 모델링하였고 표면에서 공기에 의한 대류 (Convection)문제와 단열재 사이의 전달 (Conduction)문제, 히터내부 액체의 자연대류 (Natural Convection) 그리고 배관을 통한 열손실의 문제를 고려한 복합적인 열전달 현상을 분석하였다.

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중소규모 화학공장의 압력방출시스템에 대한 안전성 검토 (Review of Safety for Pressure-Relieving Systems of Small to Middle Scale Chemical Plants)

  • 임지표;진대영;마병철;강성주;정창복
    • 한국안전학회지
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    • 제30권6호
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    • pp.48-55
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    • 2015
  • A variety of safety issues were investigated for chemical reactors using a toluene solvent in case of a fire at small to middle scale chemical plants. The issues covered the operation of pressure-relieving valves and the subsequent discharges of the toluene to the atmosphere either directly or through an absorber, which represent the current practice at most small chemical plants. It was shown that the safety valve on the reactor may not operate within about twenty minutes after an external fire breaks out, but, once relieved, the toluene vapor released directly to the atmosphere may form a large explosion range on the ground. It was also shown that if the discharge is routed to an existing absorber used for the scrubbing of volatile organic compounds or dusts, the column may not operate normally due to excessive pressure drops or flooding, resulting in the hazardous release of toluene vapors. This study proposed two ways of alleviating these risks. The first is to ruduce the discharge itself from the safety valve by using adequate insulation and protection covers on the reactor and then introduce it into the circulation water at the bottom of the absorber through a dip linet pipe equipped with a ring-shaped sparger. This will enhance the condensation of toluene vapors with the reduced effluent vapors treated in the packing layers above. The second is to install a separate quench drum to condense the routed toluene vapors more effectively than the existing absorber.

열음향 냉장시스템 (II) : 제작 및 실험 (Thermoacoustic Refrigerating System, Part II : Implementation and Experiment)

  • 하재규;안철용;성굉모
    • 한국음향학회지
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    • 제14권6호
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    • pp.13-20
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    • 1995
  • 본 논문에서는 열음향 냉장시스템을 실제로 설계, 제작하고 그 동작을 확인하였다. 제작된 시스템은 4인치의 중음부 스피커로 구동되며 스피커 하우징, 챔버, 스택하우징, 스택, 열교환기, 가는관, 그리고 공명구로 구성되었으며 내부에 10기압의 He을 채워 실험하였다. 실행 중 온도하강측정을 위하여 T 타입의 열전쌍을 열교환기에 부착하였고, 내부음압측정용 콘덴서 마이크로폰을 장착하였다. 스피커의 열손상을 막고 고온 열교환기를 냉각시키기 위하여 냉각수를 공급하였다. 실제 실험을 위하여 제작된 열음향기관의 전기적인 임피던스를 측정하여 공진특성을 파악하였는데, 실험 결과 설계치와는 약간 다르게 340Hz로 구동하는 것이 효율적이었다. 이러한 해석을 기초로 실제 냉장실험을 수행한 결과 $30^\circ{C}$의 조건하에서 340Hz, 50W로 구동하였을 때 $16^\circ{C}$의 냉장효과를 관찰하였다. 관찰된 냉각효과와 설계치의 차이를 규명하기 위하여 제작된 열음향기관의 미비점을 고찰하였는 바, 냉각부의 단열이 제일 중요한 문제임을 파악하였으며 그외의 보완이 필요한 사항은 이후의 진행될 연구의 과제로서 제시하였다.

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자켓의 압력 및 두께 변화에 의한 진공 자켓 밸브의 유입 열량 변화에 관한 연구 (A Study on the Heat Flow Change of Vacuum Jacket Valve According to Pressure Change and Jacket Thickness)

  • 김시범;이권희;전락원;도태완
    • Journal of Advanced Marine Engineering and Technology
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    • 제35권2호
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    • pp.232-237
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    • 2011
  • 최근 초저온 밸브 관련 산업의 급속한 발전과 함께 초저온 밸브에 대한 지속적인 연구가 이루어지고 있고 특히, 기계, 조선, 반도체 및 디스플레이 산업, 항공 우주산업분야의 비약적인 발전과 사용자의 요구 등으로 인하여 초저온용 밸브의 고성능화가 되고 있는 추세이나, 진공 단열에 관한 초저온 응용 장비들에 대한 기술개발 및 연구는 미흡한 실정이다. 본 연구에서는 초저온용 진공자켓밸브의 스템 외부에 자켓 배관을 설치 한 후 낮은 압력을 유지함으로써 외부로부터 자켓 내부로의 유입 열전달량을 감소시키는 것에 주안점을 두었고, 효과적인 전열 제어를 위하여 외부로부터 자켓 내부로의 유입 열전달량을 감소시킬수 있는 자켓 내부의 압력과 자켓부의 두께 변화에 관한 열전달 특성을 3차원 수치해석적인 방법으로 연구하여 고찰하였다.

맨홀에 설치된 지역난방 열공급관 에어벤트의 전단부 파손 원인 규명 (Failure Analysis of Air Vent Connected with Heat Supply Pipeline Under Manhole)

  • 조정민;채호병;김희산;김정구;김우철;정준철;이수열
    • Corrosion Science and Technology
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    • 제19권4호
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    • pp.196-202
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    • 2020
  • The air vent connected to a heat supply pipeline in the district heating system has been used to eliminate the existing air in the pipe, which has a detrimental effect on corrosion durability and heat efficiency. Recently, the air vent installed under a manhole for 22 years was corroded and several pinholes were detected in the front-end of the air vent. To identify the cause of the failure, thickness reduction, corrosion products, and water quality were examined. The corrosion damage was significant at the outside of the front-end of the air vent where the insulator was covered. While a thin oxide layer was formed in the interior of the tube, the coarse and porous corrosion products consisting of magnetite and hematite were found externally. Water flowing into the thermal insulator was absorbed by the insulator following hydrolysis. The hydrolyzed insulator ejected the corrosion factors such as Cl-, SO42-, and NH4+. The findings suggest that the corrosion under insulation due to rain water is the main cause of the underlying failure in the air vent.

설비공학 분야의 최근 연구 동향 : 2013년 학회지 논문에 대한 종합적 고찰 (Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2013)

  • 이대영;김사량;김현정;김동선;박준석;임병찬
    • 설비공학논문집
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    • 제26권12호
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    • pp.605-619
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    • 2014
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2013. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of fluid machinery, pipes and relative parts including orifices, dampers and ducts, fuel cells and power plants, cooling and air-conditioning, heat and mass transfer, two phase flow, and the flow around buildings and structures. Research issues dealing with home appliances, flows around buildings, nuclear power plant, and manufacturing processes are newly added in thermal and fluid engineering research area. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results for general analytical model for desiccant wheels, the effects of water absorption on the thermal conductivity of insulation materials, thermal properties of Octadecane/xGnP shape-stabilized phase change materials and $CO_2$ and $CO_2$-Hydrate mixture, effect of ground source heat pump system, the heat flux meter location for the performance test of a refrigerator vacuum insulation panel, a parallel flow evaporator for a heat pump dryer, the condensation risk assessment of vacuum multi-layer glass and triple glass, optimization of a forced convection type PCM refrigeration module, surface temperature sensor using fluorescent nanoporous thin film. In the area of pool boiling and condensing heat transfer, researches on ammonia inside horizontal smooth small tube, R1234yf on various enhanced surfaces, HFC32/HFC152a on a plain surface, spray cooling up to critical heat flux on a low-fin enhanced surface were actively carried out. In the area of industrial heat exchangers, researches on a fin tube type adsorber, the mass-transfer kinetics of a fin-tube-type adsorption bed, fin-and-tube heat exchangers having sine wave fins and oval tubes, louvered fin heat exchanger were performed. (3) In the field of refrigeration, studies are categorized into three groups namely refrigeration cycle, refrigerant and modeling and control. In the category of refrigeration cycle, studies were focused on the enhancement or optimization of experimental or commercial systems including a R410a VRF(Various Refrigerant Flow) heat pump, a R134a 2-stage screw heat pump and a R134a double-heat source automotive air-conditioner system. In the category of refrigerant, studies were carried out for the application of alternative refrigerants or refrigeration technologies including $CO_2$ water heaters, a R1234yf automotive air-conditioner, a R436b water cooler and a thermoelectric refrigerator. In the category of modeling and control, theoretical and experimental studies were carried out to predict the performance of various thermal and control systems including the long-term energy analysis of a geo-thermal heat pump system coupled to cast-in-place energy piles, the dynamic simulation of a water heater-coupled hybrid heat pump and the numerical simulation of an integral optimum regulating controller for a system heat pump. (4) In building mechanical system research fields, twenty one studies were conducted to achieve effective design of the mechanical systems, and also to maximize the energy efficiency of buildings. The topics of the studies included heating and cooling, HVAC system, ventilation, and renewable energies in the buildings. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment is mostly focused on indoor environment and building energy. The main researches of indoor environment are related to infiltration, ventilation, leak flow and airtightness performance in residential building. The subjects of building energy are worked on energy saving, operation method and optimum operation of building energy systems. The remained studies are related to the special facility such as cleanroom, internet data center and biosafety laboratory. water supply and drain system, defining standard input variables of BIM (Building Information Modeling) for facility management system, estimating capability and providing operation guidelines of subway station as shelter for refuge and evaluation of pollutant emissions from furniture-like products.

대형 풍력터빈 절연커플링 시험장치 개발 및 평가 (Development and Evaluation for the Insulated Coupling Test Machine of a Large Wind Turbine)

  • 주성하;김동현;오민우;김수현;배준우;강종훈;이형우;김경희
    • 대한기계학회논문집B
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    • 제40권8호
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    • pp.543-556
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    • 2016
  • 본 연구에서는 5 MW 급 대형 풍력터빈 절연커플링의 시험평가 장치를 자체설계 개발하였다. 3 MW 급 대형 풍력터빈용 절연커플링에 대한 공인성능시험평가를 수행하고 시험장치에 대해서는 개발요구도, 장치설계, 기능적 고려사항, 구조진동해석 및 검토 결과를 제시하였다. 본 연구에서 고려한 대형 풍력용 절연커플링 모델과 같이 필라멘트와인딩 공법으로 제작된 두꺼운 유리섬유 복합재 파이프의 경우 shell 요소 기반의 유한요소 해석기법과 두께 효과를 정확하게 모델링 할 수 있는 복합재 적층형 3D solid 모델링 기법의 비교결과를 제시하였다. 또한 다수의 판스프링이 적층된 형태로 제작된 디스크팩 구조에 대한 효과적인 비선형 유한요소 해석기법을 제시하고 시험평가 결과와 비교 검증을 수행하였다.

MIRIS 우주관측카메라의 기계부 개발 (DEVELOPMENT OF THE MECHANICAL STRUCTURE OF THE MIRIS SOC)

  • 문봉곤;정웅섭;차상목;이창희;박성준;이대희;육인수;박영식;박장현;남욱원;;;양순철;이선희;이승우;한원용
    • 천문학논총
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    • 제24권1호
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    • pp.53-64
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    • 2009
  • MIRIS is the main payload of the STSAT-3 (Science and Technology Satellite 3) and the first infrared space telescope for astronomical observation in Korea. MIRIS space observation camera (SOC) covers the observation wavelength from $0.9{\mu}m$ to $2.0{\mu}m$ with a wide field of view $3.67^{\circ}\times3.67^{\circ}$. The PICNIC HgCdTe detector in a cold box is cooled down below 100K by a micro Stirling cooler of which cooling capacity is 220mW at 77K. MIRIS SOC adopts passive cooling technique to chill the telescope below 200 K by pointing to the deep space (3K). The cooling mechanism employs a radiator, a Winston cone baffle, a thermal shield, MLI (Multi Layer Insulation) of 30 layers, and GFRP (Glass Fiber Reinforced Plastic) pipe support in the system. Optomechanical analysis was made in order to estimate and compensate possible stresses from the thermal contraction of mounting parts at cryogenic temperatures. Finite Element Analysis (FEA) of mechanical structure was also conducted to ensure safety and stability in launching environments and in orbit. MIRIS SOC will mainly perform Galactic plane survey with narrow band filters (Pa $\alpha$ and Pa $\alpha$ continuum) and CIB (Cosmic Infrared Background) observation with wide band filters (I and H) driven by a cryogenic stepping motor.