Composite seals

This invention concerns the area of annular composite seals particularly intended for being pressed between two surfaces to be applied tightly to each other, in a leak tight manner. Metal seals, particularly those of the type comprising a core made of a spiral spring and surrounded by a metal lining, are growing considerably in use at the present time, particularly because of their ability to withstand high temperatures and their life which is very superior to elastomer seals and they are being considered for use in applications linked to a relatively dangerous environment, for instance in the area of nuclear energy, where the techniques make use of highly toxic gases, acid solutions, and more generally different types of dangerous substances