Device for sealing between two coaxial ducts and assembly

A sealing device comprising:

• an axially deformable tubular membrane having a first annular end and a second annular end,
• a first annular coupling ring fastened to the first end of the tubular membrane and having a lateral annular flange providing an axial annular attachment space, and
• a second coupling ring fastened to the second end of the tubular membrane and having a projecting lateral annular flange extending axially away from the first annular end of the tubular membrane and radially offset away from said axial annular attachment space relative to said lateral side of the tubular membrane;
• wherein the first annular coupling annular ring comprises an interior annular flange, an external annular flange offset radially relative to the interior annular flange and connecting annular portion connecting the exterior annular flange and the interior annular flange,
• wherein one of the interior and external annular flanges of the first annular coupling annular ring is fastened to the first end of the membrane and the other of the interior and external annular flanges delimits together with the membrane the axial annular attachment space, and
• wherein the axial annular attachment space is axially open on the side of the second annular end of the tubular membrane.