Joint for submarine connections

Rotatable coupling (60) for connecting pipes, said coupling comprising

• a first hollow female element (61) suited to be connected, for example, to a first portion (51) of a pipe or to a pipe fitting (202), and
• a second tubular male element (6) with a first end portion at least partially housed inside said first female element (61) so as to define an inner common space through which a fluid can flow, and with a second end portion suited to be connected to a second portion (52) of a pipe,
• said first and said second element (61, 6) being suited to be rotated with respect to each other, said second tubular male element (6) comprising a first abutment surface (6S),
• wherein said rotatable coupling (60) furthermore comprises a third tubular hollow element (12) housed inside said first female element and provided with a second abutment surface (1S) substantially opposite said first abutment surface (6S) in such a way as to define a first interspace (I),
• wherein said third hollow element is suited to be translated along a direction substantially orthogonal to said first and said second abutment surface (6S, 1S) between a closed configuration, in which said first and said second abutment surface (6S, 1S) are positioned at a minimal mutual distance from each other, and an open configuration, in which said first and said second abutment surfaces (6S, 1S) are positioned at a distance from each other that exceeds said minimal mutual distance,
• wherein at least one first elastic sealing element (B1) is interposed between said first and said second abutment surface (6S, 1S), and wherein with said third hollow element (12) in said closed configuration said first elastic sealing element (B1) is placed in contact with both said first abutment surface (6S) and said second abutment surface (1S)
• characterized in that the surface areas of the portions of the external surface of said first elastic sealing element (B1) respectively in contact with said first and with said second abutment surface (6S, 1S) are minimal when there is no fluid and increase when said first elastic sealing element (B1), which is in the shape of a ring in longitudinal cross section, is subjected to pressure by a fluid present inside said first interspace (I).