Volumetric metering device for container filling machine

A metering device for a machine for filling containers with a product, comprising:

• a cylinder body defining a metering chamber, configured to be filled with the product;
• a piston inside the metering chamber and separating the metering chamber into a supply compartment and a metering compartment, with the piston including a passage that communicates between the supply compartment and the metering compartment in such a way as to allow passage of the product between the supply compartment and the metering compartment;
• a valve for closing the passage;
• and
• a mover that facilitates movement of the valve or of the piston along the length of the cylinder body, wherein the valve includes a driver arranged on either side of the piston in such a way that the movement respectively of the valve or of the piston along the length of the cylinder body in a discharge direction drives the movement respectively of the piston or of the valve in the discharge direction and the movement respectively of the valve or of the piston along the length of the cylinder body in a transfer direction opposite the discharge direction, drives the movement respectively of the piston or of the valve in the transfer direction.