transferred with a suction die 12 to a packaging container the carrier strip 7 which has openings 8 each coinciding with one aperture 3 of the base plate 2 of each valve 1 is advanced incrementally in a horizontal plane the valves are disposed on its underside so that the inner ends of the valve channel 5 are accessible from above through the opening 8 and through the aperture 3 in the base plate 2 and the backing foil 4 forms a bottom a sealant delivery device 20 is disposed at one station along the delivery route of the carrier strip 7 it has a nozzle 21 in the form of a hollow needle pointing downward and ending just above the carrier strip 7 in the region of an opening 8 preferably the nozzle 21 ends not centrally but rather near the edge of the opening 8 of the carrier strip 7 or of the aperture 3 in the base plate 2 of a valve 1 so that a droplet 6 of sealant expressed by the nozzle 21 and dropped through the opening 8 and the aperture 3 onto the backing foil 4 of a valve 1 comes at least partly into contact with the edge of the aperture 3 of the base plate 2 that defines one end of the valve channel 5 for this purpose it may be useful to advance the carrier.