Seal arrangement for adjoining walls of a propulsion nozzle of an engine

Apparatus for sealing first and second wall elements, one of said wall elements having an end face facing a surface of the other of said wall elements with a clearance therebetween, said one wall element having a slot therein which opens at said end face into said clearance, a sealing element movably supported in said slot and projecting therefrom to contact the surface of said other wall element and form a primary seal therewith, said one wall element forming chambers on opposite sides thereof which are sealed from one another by said primary seal and which are subjected to differential pressures, actuating means for pressing said sealing element against the surface of said other wall element, said actuating means comprising a pressure chamber in said one wall element, a plunger movably carried in said one wall element, said plunger being subjected to pressure in said pressure chamber, causing said plunger to bear against said sealing element to urge the sealing element against the surface of said other wall element, said sealing element projecting from said slot into said clearance and being subjected on opposite sides thereof to the pressure differential in said chambers to cause said sealing element to be urged by said pressure differential against a side surface of the slot to form a secondary seal thereat.