Improved hermetic seals for casing structures, particularly applicable for insulating-casing structures utilized in connection with gas-type piston-flow circuit-interrupters, are provided including end metallic closure-plate members, which are hermetically sealed in a gas-tight manner to the ends of...http://www.google.es/patents/US3959577?utm_source=gb-gplus-sharePatente US3959577 - Hermetic seals for insulating-casing structures
