Patent ID: 8163064

Claim:
A method for providing a leak-proof membrane element ( 1 ) for the selective separation or cleaning of gas of the type wherein a metal foil (membrane) ( 3 ) or such metal foil coated on one or both sides thereof with other materials (barrier/protective layers) ( 43 , 44 ), and being selectively permeable for specific gases, is deposited onto a supporting stock (substrate) ( 2 , 20 ) exhibiting a high gas flux and being made of metal, ceramic, polymer, or combinations thereof, and wherein connection means ( 4 , 21 , 34 ) are provided on the ends/edges of the substrate allowing the membrane element to be installed in a housing, characterized in that the method comprises: a) winding or depositing with overlapping joints ( 8 ) bands or flakes of the foil (pure metal foil or metal foil ( 3 ) partially coated with barrier/protective coatings) having a thickness of less than 10 micrometers on top of/on the outside of the substrate ( 2 , 20 ), b) then sealing the ends/edges of the substrate by fitting connection means ( 4 , 21 , 34 ) onto the substrate with the membrane, using a sealant material ( 7 , 25 ) between the substrate and connection means that does not let through undesired gases, c) then joining by diffusion bonding the overlapping joints ( 8 ) to a continuous, non porous membrane layer, by heating the substrate ( 2 , 20 ) coated with the metal foil ( 3 ) while having zero or a positive overpressure on the metal side.