Process for operating freeze-drying plants having a chamber and loading and unloading devices, and appropriate plants of this type

The method involves using loading and unloading devices with transfer from a conveyor belt (6) by a transfer table (7). During loading of the superposed stands (4) the transfer table substantially retains its operating position and at least the area of the loading opening (2) above the transfer table is closed after the containers have been pushed by the slider (8) from the conveyor belt over the table to the stands. The area of the loading opening underneath the transfer table is closed in that the table in the last phase of its movement into its operating position rests on the lower edge of the opening. An independent claim is included for a freeze dryer unit with chamber containing superposed stands for the containers wherein the closing means (11,12) for the loading opening can be actuated so that when the transfer table is pushed in the area of the opening above same is closed.