Abstract: A conveyor moves in a horizontal transport direction through a closing station and has plates forming a succession of transverse rows of cutouts each holding a respective vessel. A stationary main frame at the station is traversed by the conveyor extends. A secondary frame is carried by guides on the main frame for movement of the secondary frame between a use position in the main frame above the conveyor and a service position projecting transversely from the main frame and supported horizontally transversely offset from the conveyor. A plurality of respective sealing heads carried on the secondary frame can put covers on the vessels when the secondary frame is in the use position.