A lower sealing valve unit for a charging system of a shaft furnace includes a housing having a pair of inlets and at least one outlet; a valve seat associated with each inlet; and a flap associated with each valve seat and adapted for, in a closed position, engaging the valve seat to sealingly close the inlet, each flap being supported by a pivotable shaft allowing displacement between the closed position and an open position off the associated valve seat, where a common structure, mounted to one side of the housing, includes a pair of drive mechanisms, each connected to one of the pivotable shafts for independent actuation thereof, the shafts passing coaxially though the housing side and being supported by the common structure.