An exhaust opening of a process chamber (12) contained in a vacuum chamber (11) is connected to an exhaust line (13) by a connector comprising a bellows (03) with one end which is connected to the exhaust line (13) fixed to a housing and its opposite end carrying a coupling tube (02) for connecting to a coupling ring (01) which surrounds the exhaust opening, the coupling tube (02) being elastically biased towards the same. The coupling tube (02) can be moved between a connected state where it is in contact with the coupling ring (01) and a disconnected state by an actuator reciprocatable in an axial direction perpendicular to the exhaust opening. To enable a gas-tight connection with the process chamber (12) the coupling tube (02) has lateral play such that it can align with the coupling ring (01) when a conical surface of the coupling tube (02) contacts a complementary conical surface on the coupling ring (01) in the connected state. The actuator comprises two rods (04) which extend through drill holes of an outward extending holding ring (05) of the coupling tube (02) and interact with the same in such a way that the lateral position of the coupling tube (02) is fixed in the disconnected state.