Filling valve having a liquid chamber, a gas chamber and a medium chamber, and filling machine comprising the same

A filling valve comprising:

• a hollow housing;
• a sliding valve assembly disposed in the hollow housing, said sliding valve assembly and said hollow housing forming a liquid chamber and a gas chamber;
• a liquid inlet which connects said liquid chamber with a liquid supply pipe;
• a gas inlet which connects said gas chamber with a gas supply pipe;
• wherein said sliding valve assembly comprises:
• a hollow valve rod provided with a through hole opening in said gas chamber at an upper end of said valve rod, said valve rod sliding with respect to the housing between an open position in which the valve rod opens an aperture in the housing, thereby allowing liquid to flow from the liquid chamber through said aperture, and a closed position in which the valve rod closes said aperture, and
• a sliding piston disposed in the housing between an open position in which a lower end of the piston is spaced from the upper end of the valve rod, thereby allowing gas to pass from the gas chamber to the through hole in the valve rod through the opening formed at the upper end of the valve rod, and a closed position in which the lower end of the piston contacts and seals the upper end of the valve rod.