Optimized connection assembly between two portions of a cryogenic line, comprising a double sealing barrier, a fluid expansion chamber and a detector for detecting the presence of the fluid in said chamber

A flange-connection assembly between two portions of a line for transporting a cryogenic fluid in an inner conduit of the line, the flange-connection assembly comprising:

• a first line portion, and
• a second line portion,
• the first line portion comprising a first connection flange arranged at one of its ends and configured to be held in contact with a second connection flange, arranged at one of the ends of the second line portion,
• at least one of said first connection flange and second connection flange comprising a first groove for positioning a first seal,
• said first groove being arranged around said inner conduit, and
• at least one of said first connection flange and second connection flange comprising a second groove for positioning a second seal,
• said second groove being arranged around said first groove for positioning the first seal and having a diameter greater than the diameter of the first groove,
• the first groove and second groove being configured such that the first seal and second seal, which are positioned therein, produce a sealed connection between the first and second connection flanges by isolating said inner conduit from the exterior of the line,
• at least one conduit opening out, at a first end, between the first groove and the second groove, and opening out, at a second end, into an expansion chamber for said cryogenic fluid,
• said expansion chamber located in one of the first connection flange and the second connection flange,
• the expansion chamber comprising an absorbent element and a detector for detecting a presence of said cryogenic fluid.