A novel pressure control system is provided for maintaining a constant predetermined excess pressure in a fluid dispensing container, comprising a high-pressure plastic vessel having an inner chamber, a closed end and an open end, and a pressure control device with a valve, which pressure control device is mounted on the open end of the high-pressure vessel, whereas a passageway is provided from the inner chamber to the outside, which is controlled by the valve, wherein the high-pressure vessel is essentially spherical.