An arrangement of a biconical annular seal having a laid down V shaped cross-section, in an annular groove having a trapezoid shaped cross-section, a small base of the trapezoid corresponding to a cylindrical bottom of the groove and being radially inwardly open at a great base of the trapezoid. The seal includes a radially outer annular heel and two generally conical annular wings extending radially inwardly from the heel, an inner radial end of each wing being axially bearing against an associated wall of the groove. The seal is mounted in the groove such that the heel of the seal is located radially distal to a bottom of the groove.