Patent ID: 7454925

Claim:
A method of making glass comprising: heating a glass feed material to a first temperature within a first melting furnace to form a glass melt; flowing the glass melt from the first melting furnace to a second melting furnace separate from the first melting furnace through a connecting tube comprising a refractory metal, the connecting tube further comprising an inside surface and an outside surface disposed between a first end and a second end wherein the second end is concentric with the outside surface of the tube and the inside surface of the second end is in direct contact with the back wall of the second melting furnace and positioned proximate a first intermediate position along the length of the tube; heating the glass melt in the connecting tube to a second temperature at least substantially equal to the first temperature by flowing a current between the second end of the tube and a second intermediate position upstream of the first intermediate position, thereby electrically heating the tube at least within the back wall of the second furnace within which the connecting tube is inserted; and wherein the second end of the tube does not contact the outside of the tube at the first intermediate position.