Method and apparatus for delivering a cased glass stream

Abstract

Apparatus for forming a cased glass stream having an inner core glass surrounded by an outer casing glass includes a first orifice for receiving core glass from a first source. A second orifice is vertically spaced beneath and aligned with the first orifice, and is surrounded by an annular chamber that communicates with the second orifice through the gap between the first and second orifices. A spout delivers casing glass from a second source through a tube to the annular chamber in such a way that glass flows by gravity from the first and second sources through the orifices to form the cased glass stream. A plurality of gas burners are disposed in the spout above the glass pool. The casing glass delivery spout is configured for improved heat transfer to, and improved heat retention within, the casing glass pool within the spout. Specifically, the glass pool surface area is enlarged, and the glass pool depth is reduced. Free space above the glass pool is enlarged to accommodate gas flames from more burners, and to increase surface heat radiation into the glass pool. The housing that supports the spout is designed such that an annular spout support surface engages the spout radially outwardly of the spout opening(s) for reducing heat transfer to the housing from casing glass flowing through the opening.