| 摘要 |
The welding of a tight envelope is performed in two stages (8, 9), with an intermediate sucking up by an appendage with holes (6, 7) to create a vacuum in an envelope and strengthen the insulation offered by the interlining (1). When the second weld (9) has been performed, the appendage having the hole may be withdrawn. An electric resistance seam weld is preferable. One can thereby use welding procedures under atmosphere and weld metallic envelopes.
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