the seal sandwich!
The seal sandwich is composed of:
A large seal,
the shower screen,
A round seal,
a round metal plate.
Without waiting any longer, here are Lucio's fantastic pictures!
This is the "naked" top of the coffee machine, with the inner tube attached to it:
The large rubber head seal - cut to fit the form - is slipped through to lay on the platform:
On this large seal, the shower screen placed, kept in place by a round rubber seal:
The sandwich is ready!!!