Filling head for a liquid tank

The filling head (100) comprises a filler pipe (104) that is used for insertion of a filling nozzle. A seal element is circulated diagonally around a longitudinal axis of the filler neck for sealing the filler pipe. The seal element is formed by a resilient annular disc with an insertion opening for insertion of the filling nozzle. The annular disc is provided with a reinforcement section for reinforcing the seal element around the insertion opening.