Abstract: This disclosure relates to a method and apparatus for feeding material to a gas generator. A cell feeder is provided for preventing backflow of gases through the feeding apparatus from the gas generator. The cell feeder includes a housing having an axial passage extending therethrough defining a path of travel for material from an inlet opening to an outlet opening, first and second pistons mounted in the housing for compressing and transferring material received in the housing along the path from the inlet to the outlet, each of the pistons also alternately blocking and unblocking the path whereby material received within the housing will be compressed prior to the opening of the outlets, thereby preventing the backflow of gases.