Metallic evacuated double-walled vessel and production method therefor

摘要

A method for making a metallic evacuated double-walled vessel consisting of metallic inner and outer vessels with an evacuated thermal insulating layer being formed by the space between the inner vessel and the outer vessel. In the present invention, a prior-to-sealing double-walled vessel is formed by forming a concavity in one of either the inner vessel and the outer vessel, and punching in the concavity an evacuation hole through which to carry out vacuum evacuation. A solid sealing hot charge is then disposed prior to vacuum heating at a position directly above the evacuation hole of the prior-to-sealing double-walled vessel with an interval of space being maintained between the sealing hot charge and the evacuation hole. The prior-to-sealing double-walled vessel is then placed inside a vacuum heating furnace, and vacuum evacuation of the cavity between the inner vessel and the outer vessel is carried out via the evacuation hole. The sealing hot charge is heated and melts, causing it to drop down onto the evacuation hole and the vicinity thereabout, filling the evacuation hole. The sealing hot charge then cools and hardens, vacuum sealing the vessel.