Abstract: A sterilization container is provided with relatively large top and bottom apertures to allow hot steam to rapidly pervade the interior of the container through the top while flushing cool air out the bottom. The apertures are provided with pressure actuated valves with large cross sections to minimize impedance to gas flow when the valves are open. The pressure-sensitive elements of the valves are set such that the valves close to seal the apertures when the external pressure is at atmospheric, and rapidly open fully when the pressure begins to rise in the autoclave as steam is admitted at the start of a sterilization cycle. When the external pressure is returned to atmospheric at the end of the cycle, the pressure-actuated valves close to provide a sealed container for removal from the autoclave.