Method and apparatus for delivering a cased glass stream

In a method of forming a glass stream comprising a first inner layer and a second outer layer which includes providing a spout having a first generally vertical orifice, delivering molten glass from a first source through said first orifice, and delivering glass from a second source such that the glass from said second source provides an outer layer about the glass from the first source, the improvement comprising:

• providing a resistance heated tube assembly having an inlet end and an outlet end through which the glass flows from said second glass source for said outer layer,
• providing a second orifice in vertically spaced aligned relation below said first orifice,
• providing an annular chamber around said second orifice,
• positioning said tube assembly such that the inlet end receives glass from said second source and the outlet end delivers glass to said annular chamber,
• delivering glass from said first source through said first orifice to and through said second orifice,
• delivering glass from said second source from the outlet end of said resistance heated tube assembly to said annular chamber and between said first and second orifices such that said glass from said second source provides an outer layer to said glass from said first source, and glass flowing through said second orifice comprises said first inner layer and said second outer layer, and
• providing a casing about said first source and providing a generally vertical notch in said casing into which said outlet end of said tube assembly is positioned.

In an apparatus for forming a glass stream comprising a first inner layer and a second outer layer which includes a spout having a first generally vertical orifice, means for delivering molten glass from a first source through said first orifice, and means for delivering glass from a second source such that the glass from said second source provides an outer layer about the glass from the first source, the improvement comprising:

• a resistance heated tube assembly having an inlet end and an outlet end through which the glass flows from said second source for the outer layer,
• an electrically heated collar below said spout between said spout and said first orifice,
• a second orifice in vertically spaced relation below said first orifice,
• an annular chamber around said second orifice, said tube assembly being positioned such that the inlet end receives glass from said second source and the outlet end delivers glass to said annular chamber, such that glass from said first source is delivered through said spout, said first orifice and said second orifice in sequence, and glass from said second source flows from the outlet end of said resistance heated tube assembly to said annular chamber and between said first and second orifices such that said glass from said second source provides an outer layer to said glass from said first source, and glass flowing through said second orifice comprises said first inner layer and said second outer layer, and
• a casing about said electrically heated collar, said casing including a generally vertical notch in said casing in which said outlet end of said resistance heated tube assembly is disposed.

In an apparatus for forming a cased glass stream having an inner core glass surrounded by an outer casing glass, said apparatus including a spout for receiving core glass for a first source and delivering such glass through a first orifice, means forming a second orifice vertically spaced beneath and aligned with said first orifice with an annular chamber surrounding said second orifice and communicating with said second orifice through a gap between said first and second orifices, and means for delivering casing glass from a second source to said annular chamber such that glass flows by gravity through said orifices from said first and second sources to form said cased glass stream, the improvement in which said spout comprises:

• a reservoir for receiving and holding said core glass and having at least one lower opening of a first diameter,
• an orifice ring positioned beneath said reservoir and having at least one opening of second diameter less than said first diameter aligned with said at least one lower opening of said first diameter and forming said first orifice, and
• a collar of uniform inside diameter equal to said first diameter extending from said at least one lower opening to said orifice ring and thereby spacing said reservoir from said orifice ring so as to increase hydrostatic pressure on glass at said first orifice from said reservoir,
• said collar and said reservoir forming an abutment joint surrounding said at least one lower opening, and said apparatus further comprising means for cooling said joint so as to control leakage of glass through said joint, said cooling means comprising a hollow band surrounding said joint and means for delivering cooling air to said band, said band being circumferentially segmented around said collar for accommodating thermal expansion of said collar, clamp means for holding said band in place around said joint, and spring means for maintaining clamping pressure on segments of said band while accommodating expansion as a result of heating of said reservoir and collar.

In an apparatus for forming a cased glass stream having an inner core glass surrounded by an outer casing glass, said apparatus including a spout for receiving core glass for a first source and delivering such glass through a first orifice, means forming a second orifice vertically spaced beneath and aligned with said first orifice with an annular chamber surrounding said second orifice and communicating with said second orifice through a gap between said first and second orifices, and means for delivering casing glass from a second source to said annular chamber such that glass flows by gravity through said orifices from said first and second sources to form said cased glass stream, the improvement in which said spout comprises:

• a reservoir for receiving and holding said core glass and having at least one lower opening of a first diameter,
• an orifice ring positioned beneath said reservoir and having at least one opening of a second diameter less than said first diameter aligned with said at least one lower opening of said first diameter and forming said first orifice,
• a collar of uniform inside diameter equal to said first diameter extending from said at least one lower opening to said orifice ring and thereby spacing said reservoir from said orifice ring so as to increase hydrostatic pressure on glass at said first orifice from said reservoir, and
• a casing surrounding said reservoir, said casing having a notch through which extends said means for delivering casing glass from said second source to said annular chamber.