Device (10) for achieving communication, via a coupling means, between a first chamber (1) and a second chamber (2). The coupling means comprises, on the same side as the first chamber (1), a first shut-off member (41), and, on the same side as the second chamber (2), a second shut-off member (4) comprising a second flange (52) forming a seat for a second removable shutter element (72). The coupling means further comprises means of sealed connection between two flanges (51) and (52). The second chamber (2) being defined by the inside of a flexible and sealed bag (15), the border of the mouth of which is connected in a sealed way to the second flange (52). When the coupling, means is in an uncoupled position, the flexible bag (15) comprises a band (15d) extending the bag (15) continuously beyond the second flange (52), defining a closed (15f) and sealed, but openable envelope (12) for protecting the second shut-off member (42).
