Abstract: In a rotary vacuum sealed wafer transport system for transporting semiconductive wafers between ambient atmosphere and subatmospheric pressure within a wafer processing station, the wafers, on a conveyor web pass through a slot in the vacuum chamber of the processing station. The evacuable envelope of the processing station has an external concave face portion intersecting with a generally planar face portion with the slot being positioned generally at the intersection of the concave and planar face portions. A deformable elastic roller, preferably pneumatically inflated, is disposed for rolling sealing engagement with the conveyor web and wafer and for wiping sealing engagement with portions of the planar and concave faces to provide a gas tight seal of the slot while permitting passage of the conveyor web with the wafers thereon into the evacuated wafer processing station. In a preferred embodiment, the conveyor web passes through input and output slots with pneumatic rollers sealing the pair of slots.