PURPOSE: To enable repetitive communication between isolated chambers by providing an annular connector and cutting device for the membrane that are provided with respective isolation membranes and capable of sealed slide of closed piece.

CONSTITUTION: An annular connector 5 in a confined chamber 1 is equipped with an inner wall 5A with a fixed cross-section that enables sealed slide of successive closure pieces 7 and 7X having a closure membrane 14 and 14. It also defines an annular cutting device 9B for an entrance-exit opening and the membrane 14 and 14, and another membrane adhered thereto. Each transfer machine 3 has a passageway's slot and a closure membrane 22. The two membranes 14 and closure membrane 22 have been so structured as to adhere to each other during the joining up of the confined chamber 1 and the transfer machine 3, and the adhered membranes 14 and 22 are cut by the annular cutting device 9B to define a discoid D with two at least peripherally joined. The discoid D is removed by the transfer machine 3 to form a passage, and a subsequent uncut closure piece 7X is installed in the connector 5 from the interior of the confined chamber 1 and replaced with the closure piece 7 to be removed.