Patent ID: 8408417

Claim:
A tank comprising a storage space enclosed by a substantially fluid-tight tank wall, wherein the tank wall comprises: a curing material for causing the tank wall to pass from a first flexible state to a second substantially form-retaining shape, wherein the curing material of the tank has not yet cured and the tank wall is in a flexible state, wherein the tank wall is provided with a preformed opening for substantially fluid-tight co-action with a preformed closure, wherein the tank wall has an inner surface and an outer surface, wherein the opening of the tank wall is enclosed with a substantially form-retaining frame, said frame having two rings, a first ring on the inner side of the tank wall placed against the inner surface of the tank wall and a second ring on the outer side of the tank wall placed against the outer surface of the tank wall, said first ring and second ring being attached to each other, and wherein the first ring on the inner side of the tank wall is transparent to a source required for curing the curing material so that the tank wall becomes full hardened between the two rings.