Systems and methods for high-temperature electric feedthroughs having beaded metallic gaskets

A sealing subassembly for isolating a ceramic electrical insulator from compressive stress within a high-temperature feedthrough, comprising:

• a ceramic washer;
• a first annular metallic gasket disposed on a first axial side of the ceramic washer;
• a second annular metallic gasket disposed on a second axial side of the ceramic washer;
• wherein each annular metallic gasket includes a circumferentially continuous axially projecting bead configured to:
• (a) concentrate compressive load along a narrow sealing band, and (b) provide elastic compliance during thermal cycling, thereby distributing axial loading across the ceramic washer and reducing fracture risk.

A method of maintaining sealing preload in an electric feedthrough exposed to repeated thermal cycling above 600° C., comprising:

• positioning a ceramic washer on a pass-thru stud;
• disposing a first beaded metallic gasket on a first axial side of the ceramic washer;
• disposing a second beaded metallic gasket on a second axial side of the ceramic washer;
• and
• applying axial compression such that circumferential beads of the beaded metallic gaskets plastically deform to establish a sealing interface and subsequently elastically deflect during thermal expansion and contraction to maintain axial preload.