Method and apparatus for delivering a cased glass stream having a raised and sealed orifice bushing

Apparatus for delivering a cased glass stream having an inner core glass surrounded by an outer casing glass includes a first or upper orifice ring (24) having at least one orifice (22) for receiving core glass, and a second or lower orifice ring (26) secured beneath the first orifice ring and having a second orifice (28) aligned with each first orifice. A chamber (30) for receiving casing glass is formed between the first and second orifice rings surrounding the second orifice. A bushing (58) is received in an opening in the second orifice ring to form each second orifice in the second orifice ring. The bushing has a first radially extending flange (62) supported on an upper surface (52) of the second orifice ring and a bushing end spaced upwardly from the first flange for admitting casing glass from the chamber to the second orifice. The first flange thus effectively spaces the bushing end above the surface of the second orifice ring, eliminating any need for the ceramic pedestal that can erode due to casing glass flow along the surface of the second orifice ring. The flange remains in firm facing abutment with the second orifice ring surface, reducing leakage of casing glass between the bushing and the opposing surface of the second orifice ring.