摘要 |
A high pressure multi-purpose seal for use with pressure vessels and other equipment requiring demountable access fittings withstands pressures thousands of times above atmospheric pressure at both cryogenic and elevated temperatures. The cryogenic high pressure seal comprises a stack of indium, brass and fluorocarbon plastic sealing rings disposed about an access opening in the pressure vessel. A gland nut type closure is tightened against the seal stack which compresses it and causes the indium rings to extrude and seal against the closure and pressure vessel walls. The seal exhibits negligible leakage and provides exceptional pressurization and depressurization cycle life at both high pressures and cryogenic temperatures. The instant invention also comprehends a high pressure seal suitable for use at elevated temperatures (370 DEG to 400 DEG Celsius or 700 DEG to 750 DEG Farenheit). Substitution of aluminum rings or rings of a material having similar temperature and stress characteristics for the indium rings and substitution of perfluorelastomer rubber rings for the fluorocarbon plastic rings extends the operational temperature range of the seal upward several hundreds of degrees.
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