• Title/Summary/Keyword: MIL-STD-740-2

Search Result 4, Processing Time 0.018 seconds

Reduction of Fire Main Pipe System's Vibration Using Back Flow Prevent Globe Valve (역류방지 글로브 밸브를 이용한 소화 주관계의 진동개선)

  • Park, Mi-You;Han, Hyung-Suk;Lee, Seuk-Soo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 2009.04a
    • /
    • pp.518-523
    • /
    • 2009
  • Main source of URN(Underwater Radiated Noise) which is related to the ship's survivability is divided into two groups. Cavitation is main source of URN when the speed of ship is upper than CIS(Cavitation Inception Speed). But when the speed of ship is lower than CIS, main source of URN is structure-borne noise on the hull which is originated from propulsion system, pump system or transmitted vibration of pipe system. In this paper, to reduce the vibration of discharge pipe and valve system, back flow prevent globe valve and new rubber mount are applied to the ship. As the result of applying new valve and mount, the vibration is reduced drastically.

  • PDF

Reduction of Fire Main Pipe System's Vibration Using Back Flow Prevent Globe Valve (역류방지 글로브 밸브를 이용한 소화 주관계의 진동개선)

  • Park, Mi-You;Han, Hyung-Suk;Lee, Seuk-Soo
    • Transactions of the Korean Society for Noise and Vibration Engineering
    • /
    • v.19 no.6
    • /
    • pp.599-606
    • /
    • 2009
  • Main source of URN(underwater radiated noise) which is related to the ship's survivability is divided into two groups. Cavitation is the main source of URN when the speed of ship is upper than CIS(cavitation inception speed). But when the speed of ship is lower than CIS, the main source of URN is the structure-borne noise on the hull which is originated from propulsion system, pump system and trnasmitted vibration of the pipe system. In this paper, to reduce the vibration of discharge pipe and valve system, back flow prevent globe valve and new rubber mount are applied to the ship. As the result of applying new valve and mount, the vibration is reduced drastically.

Analysis for the Reduction of Tonal Noise in the Centrifugal Fan for the Ship Considering Structural and Electromagnetic Characteristics of the Fan-Motor System (팬-모터의 구조 및 전자기적 특성을 고려한 선박용 원심 팬의 순음 저감 분석)

  • Han, Hyung-Suk;Jang, Cheon-Ik;Lee, Sang-Gu;Koo, Ja-Hoon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • 2008.04a
    • /
    • pp.359-367
    • /
    • 2008
  • The maximum sound pressure level in a ship is restricted by the international standard such as MIL-Std. 740-1 in order to protect hearing ability for the crew on a ship. Especially, the noise of a fan system is restricted by the maximum level of the sound power according to the military specification such as MIL-F-1900A. In this paper, the reduction of tonal noise for the fan-motor system on a ship is described related to the electrical as well as structural problems. For the electrical problems, the difference of the magnetic flux caused by the variation of the air-gap is described related to the bad concentricity of the motor housing and the shaft-bearing. And for the structural problem, the resonance of the fan motor system is described.

  • PDF

Development of the Anti-vibration Base for the Onboard Equipment of the Naval Vessel Using Sandwitch Panel (샌드위치 패널을 이용한 함정탑재장비용 방진 베이스 개발)

  • Han, HyungSuk;Lee, KyoungHyun;Park, SungHo;Wi, YangHyun
    • Transactions of the Korean Society for Noise and Vibration Engineering
    • /
    • v.26 no.4
    • /
    • pp.365-374
    • /
    • 2016
  • The underwater radiated noise can be reduced by decreasing the structure borne noise of the on-board equipment. Therefore, the structure borne noise of the onborad installed equipment is strongly restricted by ROK navy with MIL-Std 740-2. Usually, the vibration transmissibility from the equipment to the hull of the ship is dependent on its mount characteristics. Even though the double mount structure is proper to apply for ship board application rather than single mount, it is not widely applied due to the weight and volume resriction of the ship. Therefore, in this research, the base using sandwitch panel which can act as double mount structure is suggested and its noise reduction capacity is verified with analytic calculation as well as experiment.