Process and apparatus for welding a hollow structure, such as a container or a tube, with inerting of its internal structure
AssigneeL'Air Liquide, Societe Anonyme pour l'Etude et l'Exploitation des Procedes Georges Claude
InventorDes Topper
Life of this patent
Estimating the term…
Abstract
First and second sub-parts are brought into contact with each other so as to form an unwelded hollow structure defining an internal volume. The internal volume of the hollow structure is inerted by introducing an inerting gas mixture into the hollow structure, the inerting gas mixture comprising from 93% to 99.8% nitrogen and from 0.2% to 7% oxygen and being produced by air permeation by means of one or more membrane modules. The first and second sub-parts are arc welded together so as to form a welded hollow structure.
Claims20
Process for arc-welding at least a first sub-part with at least a second sub-part into a hollow structure defining an internal volume, the first and second sub-parts being made of a metal or a metal alloy, comprising the steps of:
- bringing at least the first and second sub-parts into contact with each other so as to form an unwelded hollow structure defining an internal volume;
- inerting at least part of the internal volume of the hollow structure by introducing an inerting gas mixture into the hollow structure, the inerting gas mixture comprising from 93% to 99.8% nitrogen and from 0.2% to 7% oxygen;
- and
- arc welding the first and second sub-parts together so as to form a welded hollow structure.
Apparatus for arc-welding at least a first sub-part with at least a second sub-part into a hollow structure defining an internal volume, the first and second sub-parts being made of a metal or of a metal alloy, comprising:
- holding means allowing at least the first and second sub-parts to be brought into contact with each other and held together so as to form an unwelded hollow structure defining an internal volume;
- inerting means allowing at least part of the internal volume of the hollow structure to be at least partially inerted by introducing an inerting gas mixture into the hollow structure, said inerting means including:
- permeation means comprising one or more permeation membranes producing an inerting gas mixture comprising from 90 to 99.8% nitrogen and from 0.2 to 10% oxygen from air;
- inerting-gas supply means allowing the inerting gas mixture to be introduced into the hollow structure;
- and
- welding means including at least one arc-welding torch, allowing at least the first and second sub-parts to be welded together so as to form a welded hollow structure.
Dependencies are inferred from the claim text.