• Title/Summary/Keyword: 2단계 개방 밸브

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Development of a Two-Step Main Oxidizer Shut-off Valve (2단계 개방 연소기 산화제 개폐밸브 개발)

  • Hong, Moongeun
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.45 no.8
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    • pp.704-710
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    • 2017
  • The supply of the liquid oxygen into a rocket combustor is simply controlled by the 'on' and 'off' positions of a main oxidizer shut-off valve. However, the partially opened position of a three-position valve can control and optimize the engine start transients by regulating the liquid oxygen flow rate during the start-up of the engine. In this paper, the design and performances of a three-position pneumatic poppet valve, which is intended to be employed in liquid rocket engines, have been presented.

Comparison Analysis of Ready to Use Time Depending on The Type of Public Fire Hydrant of Fire-fighting Water Facility (소방용수시설의 공설소화전 종류에 따른 사용 준비시간 비교분석)

  • Jeon, Jai-In;Kong, Ha-Sung
    • The Journal of the Convergence on Culture Technology
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    • v.5 no.4
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    • pp.87-92
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    • 2019
  • The purpose of this study is to investigate the preparation time of fire-fighting water for public fire hydrants and ground, underground fire hydrants. The equipment preparation time for stage 1 was 20.50 seconds for ground type and 24.67 seconds for underground type. The reason for this difference in preparation time is that an underground fire hydrant requires additional standpipes to connect to the main conduit of Paru and the underground hydrant, which open the manhole cover. Water tank Maintenance joint with water hose male coupling of the second stage was similar to that of the ground type of 48.50 seconds and underground water tipe of 49.00 seconds. This is because the operation of connecting the fire hose to the maintenance tank of the water tank car is the same. In the third stage, the water pipe connection was 43 seconds for ground type and 174.33 seconds for underground type. The reason why the time for connecting the water pipe to the fire hydrant is large difference is that the underground fire hydrant is opened by opening the manhole cover, After connecting the stand pipe to the fire hydrant, the additional process of connecting the water pipe to the stand pipe is required, which is considered to have greatly increased the time required. The opening of Water Control Valve and spindle Valve in the fourth stage was 66.50 seconds for the ground type and 78.83 seconds for the underground type. This difference is due to the fact that the spindle of the ground fire hydrant is located on the main body and can be easily opened, but the underground type is located next to the main body under the manhole and requires additional time to connect the opening equipment.

Analysis of Elastic Wave Based Leakage Detection Technology Using Accelerometers (가속도계를 이용한 탄성파 기반 누수탐지 기술 분석)

  • Choi, Kwangmook;Lee, Hohyun;Shin, Gangwook;Hong, Sungtaek
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.24 no.9
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    • pp.1231-1240
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    • 2020
  • Water pipes are laid on the ground, making it impossible to visually detect leaks due to aging of pipes, and technology to detect leaks in pipes is mainly used to detect leaks in pipes by detecting leaks. In this paper, two accelerometers were attached to both ends of the constant water piping to calculate the time difference between the acquired data to detect leakage points. The leak test of piping was performed by installing valves at 4.3m, 8.6m, and 12.9m points on piping 17.2m, and changing the development rate of valves to 30% and 70%. Leakage can be detected for pressure drop in piping, which is 30% and 70% open valve. It is very important to detect leakage in the early stage, and it is judged that detection of the initial leak point from the algorithm applied in this paper will be possible.