Transactions of the Korean Society of Mechanical Engineers A (대한기계학회논문집A)

The Korean Society of Mechanical Engineers (대한기계학회)
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Seat Tightness of Flexible Metal Seal of Butterfly Valve at Cryogenic Temperatures

초저온 버터플라이 밸브용 탄성 메탈실의 누설방지에 관한 연구

  • Received : 2010.12.10
  • Accepted : 2011.03.21
  • Published : 2011.06.01
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Abstract

For the development of butterfly valves used in liquefied natural gas (LNG) vessels, the seat tightness is one of the important factors to be taken into account in the valve-design process. An O-ring-type metal seal with a retaining ring showing good seat tightness at cryogenic temperatures has been widely used, despite the high manufacturing costs involved. As an alternative, a flexible solid metal seal offers not only sufficient tightness of the butterfly valve, meeting specification requirements, but also relatively low manufacturing costs. In this study, a design criterion to ensure the seat tightness of the butterfly valve using the flexible solid metal seal is proposed. The contact pressure can be calculated by the simulation of the frictional contact behavior between the surface of the metal seal and the valve disc. The geometry of the flexible solid metal seal is determined so that it satisfies the design criterion for sufficient seat tightness, and is verified by experiments according to BS6755 and BS6364.

LNG 선박에 사용되는 초저온용 버터플라이 밸브의 개발에 있어, 누설검증은 가장 중요한 설계공정 중 하나이다. 초저온에서 누설방지가 가능한 실로서 인코넬 스프링과 같은 탄성지지체가 포함된 O-링 형태의 메탈실이 널리 사용되고 있으나, 제작비가 고가인 단점을 갖고 있다. 이에 대한 대안으로 부가적인 탄성지지체 없이도 누설조건을 만족시키며, 제작비가 저렴한 탄성 메탈실의 개발이 요구되고 있다. 본 연구에서는 탄성 메탈실의 누설방지를 위한 설계조건을 정립하여, 초저온 및 고압환경에서 누설방지가 가능한 탄성 메탈실의 형상을 수치해석을 통해 고찰하였다. 아울러 이를 기반으로 시제품을 개발하고, 상온 및 초저온 상태에서 BS6755 및 BS6364 에 준하는 누설시험을 실시하여 누설여부를 확인하였다.

Keywords

References

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