Abstract: An apparatus for flow-line treatment of articles has two chambers. The first chamber is a vacuum working chamber to treat articles in an artificial atmosphere. First transport means transport articles through the first chamber and at least one lock at the end of the chamber. Second transport means transport articles though the second chamber. The lock has a movable body with at least two cavities, installed inside an airtight shell. The movable body moves between a first position, in which one cavity connects with the first chamber and the first transport means extend into the cavity, and a second position, in which the cavity connects with the second chamber and the second transport means extend into the cavity. The at least two cavities are adjacent and similar and are provided with openings. Each cavity holds one carrier with articles. The first and second transport means provide simultaneous and antiparallel movement.