Filling device comprising - a filling spout comprising a globally tubular body having an inner passage with a longitudinal axis and an open lower axial end constituting the discharge aperture of the filling spout, the inner surface of the tubular body comprising a lower portion comprising a portion defining a main valve seat, - means of metering comprising a valve system (3, 6) mounted movably in the filling spout, and a control system able to longitudinally displace said valve system between a closed state wherein the valve system comes via a main closing portion of its exterior surface against the main seat in order to close the discharge aperture, and at least one open state wherein said main closing portion is separated from said main seat, said valve system comprising - a first tubular valve, called main valve, comprising a lower annular edge delimiting a lower aperture, called secondary aperture, its outer surface comprising a lower portion that extends to said lower edge and which comprises said main closing portion, its inner surface comprising a lower portion extending to said lower edge comprising a portion forming a valve seat, called secondary seat, and - a second cylindrical valve, called central valve, mounted movably in the main valve, and comprising a lower end edge, its outer surface comprising a low portion that extends to said lower end edge and which comprises a closing portion, called secondary closing portion, said control system being able to displace the main valve between a closed position, wherein its main closing portion is against the main seat, and at least one open position wherein its main closing portion is separated from the main seat, and able to displace the central valve between a closed position wherein its secondary closing portion is against the secondary seat and at least one open position wherein its secondary closing portion is separated from the secondary seat, said main valve comprising at least one opening guaranteeing a fluid communication between its inner passage and the inner passage of the spout, characterized in that said lower edge of the main valve is provided with radial grooves, exiting onto the inner surface of said main valve. - a filling spout comprising a globally tubular body having an inner passage with a longitudinal axis and an open lower axial end constituting the discharge aperture of the filling spout, the inner surface of the tubular body comprising a lower portion comprising a portion defining a main valve seat, - means of metering comprising a valve system (3, 6) mounted movably in the filling spout, and a control system able to longitudinally displace said valve system between a closed state wherein the valve system comes via a main closing portion of its exterior surface against the main seat in order to close the discharge aperture, and at least one open state wherein said main closing portion is separated from said main seat, - a first tubular valve, called main valve, comprising a lower annular edge delimiting a lower aperture, called secondary aperture, its outer surface comprising a lower portion that extends to said lower edge and which comprises said main closing portion, its inner surface comprising a lower portion extending to said lower edge comprising a portion forming a valve seat, called secondary seat, and - a second cylindrical valve, called central valve, mounted movably in the main valve, and comprising a lower end edge, its outer surface comprising a low portion that extends to said lower end edge and which comprises a closing portion, called secondary closing portion,