A plastic tube is cut into two sections which are sealed closed by a sterile method wherein the tube is loaded into two clamping jaws which flatten the tube. The tube is cut through the flattened section and the cut ends are heated to their molten state. A wafer having wings is located between the cut ends with the wings penetrating the lumens to create an internal plug as the wings force the molten material inwardly. The plugs add to the strength of the resultant seal. If desired, the molten ends are pressed into a cavity which is cooled to a temperature below the molten temperature to seal the ends. The tubes are then removed from the cavity. When it is desired to connect individual tube sections the two tube sections are placed in clamp members in axial alignment slightly spaced from each other. The ends of the tube sections are melted by a melt/wipe process and the tube sections are then pressed into contact with each other to be welded into an integral tube. The same device is used for both the sterile disconnect and connect procedures.