The dished only head can be used as an end cap or as an intermediate cap for two independent pressure chambers in a storage tank container. In any case, the thickness of the cylinder connected to the dished only head should not be less than the thickness of the head. Otherwise, a reinforcement section should be placed at the boundary between the head and the round grass for transition connection. The thickness of the cylinder reinforcement section should be greater than or equal to the thickness of the head, and the length of the reinforcement section on one side of the head or on both sides of the middle head should not be less than that of the special-shaped pipe.