Sealing mechanism for a double-lid seal structure

A seal structure for a double-lid system with an upper lid (chamber lid) for closing the opening of a first container (chamber) and a lower lid (drum lid) for closing the opening of a second container (drum), whereby the chamber lid is provided with a surrounding seal (chamber lid seal) and the corresponding opening of the drum is also provided with a circumferential seal (drum seal), the sealing mechanism being operable in such a way that the chamber lid seal and the drum seal fully retain their sealing capability with respect to both the chamber flange and the rim of the drum lid during all operations. To this end it is suggested that at least one of the two seals, preferably the drum seal, be provided with a closed annular cavity providing an air cushion at its radially inner end.