A device (1) for closing a chamber of a container having an opening for accessing the chamber comprises a plunger, a plunger seat (11), a container carrier (13) and a spacer (12). The plunger seat (11) releasably holds the plunger in a predefined alignment. The container carrier (13) is arranged to be connected to the container in a predefined position and alignment in relation to the opening of the container. The spacer (12) is arranged to position and align the plunger seat (11) adjacent to and distant from the container carrier (13) such that the opening of the container is open when the container is connected to the container carrier (13).