고압에서 사용하려면 ? Bridgman: Re-entrant 형 실린더 개발 Newhall : Controlled clearance 형 실린더 개발 고압에서 문제점 : 피스톤 / 실린더 사이의 누출이 커져 낙하속도가 빠름
O-ring Seal ? The o-ring was invented in 1936 by a 72 year old Danish-born man, Niels Christensen. During the second world war, the US government "bought" critical war-related patents after finding out the big businesses were in violation of Christensen's patent right. Christensen got a lump sum payment of $75,000 for it. 1986.Jan Space Shuttle Challenger Disaster Viton O-ring failure because of cold weather Richard Feynman When an O-ring is frozen there is a TG point (transition to glass) point where it will not bounce back. The tiny leak when the flame reach it acted as a torch against external tank and booster.
Bridgman Seal ! The Bridgman seal seals a high pressure volume by the use of an unsupported area to create a higher pressure between two pistons. A viscous material such as copper or soap-stone is used in the generated higher pressure area to seal the intended pressure area.
초고압 측정 게이지 Manganin Wire : 84 % copper, 12 % Manganese, 4% Nickel Precision resistor 로 사용 Press. Coef.=2.3 x 10 –5 /MPa Cubic face-centered solid solution of Mn and Ni in Copper isotropic compressibility of the cubic lattice no permanent change 망가닌게이지 압저항게이지
망가닌 선 : 조성 : 86 Cu-12Mn-2 Ni 조성 : 86 Cu-12Mn-2 Ni 직경 : 0.12 mm 직경 : 0.12 mm 절연 : 이중 silk 절연 : 이중 silk 게이지의 제작 열처리 방법 : 질소 기체, 140 도, 48 시간 압력 처리 : 1.4 GPa 2 회 초기저항 : 96
Resonant Silicon Gauges (RSGs) Performance Considerations: Zero Instabilities — Short term (hours to days). Random “ Noise ”— Limits pressure resolution. Tilt Sensitivity — Causes “ zero ” shifts. Calibration Instabilities — Long term shifts (months to years). High accuracy: ±0.01%, with a maximum allowable input of 500 kPa (130 kPa- range model) RSG sensor detail K. Harada, K. Ikeda, H. Kuwayama, H. Murayama, Sensors and Actuators, 73 (1999) 261-266.