Fluid container, backflow free filling device and procedure to fill a fluid container

The container has filling device which is provided for filling a container with liquid. The filling device is provided with container filling opening (40) which connects the interior (13) of container with pre-chamber (30). A filter port (20) is arranged in a position facing the container filling opening so that liquid passing through the filter port enters into container through container filling opening. An outflow opening (50) is arranged below filter port along the direction of gravitational force, for removing liquid from pre-chamber.