Noble metal duct for conducting a glass melt and method for conducting a glass melt

A method of guiding and conditioning a glass melt, said method comprising the steps of:

• a) providing a double-walled noble metal duct, wherein said double-walled noble metal duct comprises an outer noble metal pipe and an inner noble metal pipe extending within the outer noble metal pipe, so that an inner space is formed within the inner noble metal pipe and an intermediate space is formed between the inner noble metal pipe and the outer noble metal pipe, said intermediate space having an upstream entrance for said glass melt, wherein said intermediate space has an upstream entrance through which said glass melt enters said intermediate space, but said intermediate space is closed at a downstream end thereof;
• b) conducting said glass melt through said inner space of said double-walled noble metal duct into the upstream entrance of the intermediate space so that said intermediate space fills with said glass melt;
• and
• c) removing bubbles formed on said outer noble metal pipe during the conducting of said glass melt through said inner space.

A method of producing a glass article devoid of polyvalent ions, said method comprising the steps of:

• a) providing a double-walled noble metal duct, wherein said double-walled noble metal duct comprises an outer noble metal pipe and an inner noble metal pipe extending within the outer noble metal pipe, so that an inner space is formed within the inner noble metal pipe and an intermediate space is formed between the inner noble metai pipe and the outer noble metal pipe, said intermediate space having an upstream entrance for said glass melt, wherein said intermediate space has an upstream entrance through which said glass melt enters said intermediate space, but said intermediate space is closed at a downstream end thereof;
• b) conducting said glass melt through said inner space of said double-walled noble metal duct to a glass outlet and into the upstream entrance of the intermediate space s that said intermediate space fills with said glass melt;
• and
• c) removing bubbles formed on said outer noble metal pipe from an intermediate space outlet during the conducting of said glass melt through said inner space and through the glass outlet;
• and
• d) making the glass article from the glass melt flowing out through the glass outlet.