Abstract: The valve (1) comprises a body (2) delimiting a conduit (4) and having a connection portion (6) where one end of the conduit (4) opens, the connection portion (6) being intended to be connected to the storage tank (100). In addition, said valve (1) comprises a clamping member (22) movably mounted on the connection portion (6) in order to keep the connection portion (6) attached to the storage tank (100), sealing member (10) able to rotate in the conduit (4) between a closed position in which the sealing member (10) seals the conduit (4) and an open position in which the sealing member (10) opens a passage through the conduit (4), two seats (24) interposed between the sealing member (10) and the valve body (2), and elastic return means configured to keep the seats (24) and the sealing member (10) pressed together. The conduit (4) has an angled portion (42) arranged between the connection portion (6) and the sealing member (10).