| 摘要 |
A swivel joint for connecting together a pair of pipes and for transferring fluid between the pipes at ambient temperatures and at cryogenic temperatures. A cryogenic seal between the joint's relatively rotatable inner and outer elements prevents fluid leakage at cryogenic temperatures, and an ambient seal assembly between the joint elements provides a seal at ambient temperatures and prevents fluids from contacting the cryogenic seal. The ambient seal assembly includes an elastomeric O-ring retained in the outer element, and an annular sealing ring fastened to the inner element and spring-biased towards the O-ring. At ambient temperatures the sealing ring is held against the O-ring in a fluid-tight manner. As the temperature decreases, a plurality of rods or wires, or an annular sleeve, having a high coefficient degree of linear expansion, contracts and pulls the annular sealing ring away from the adjacent O-ring to prevent wear of, and other damage to, the O-ring at low temperatures.
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