Method for delivering a glass stream for forming charges of glass

In a method of forming a glass stream comprising a first inner layer and a second outer layer which consists of providing a vertical orifice, delivering molten glass from a first glass source through said orifice, and delivering glass from a second glass source such that the glass from said second glass source provides an outer layer about the glass from the first glass source as it flows through said orifice, the improvement comprising the steps of:

• (a) providing a resistance heated tube assembly comprising a corrosion resistant electrically conductive tube portion having an inlet end and an outlet end through which the glass flows from said second glass source for the outer layer;
• (b) positioning said tube potion such that the inlet end receives glass from said second source and the outlet end delivers glass to said orifice;
• (c) providing a flange at each end of said tube portion of a material which is corrosion resistant and is electrically conductive;
• (d) securing said flanges to said ends of said tube portion such that said flanges are connected uniformly about the upper end and lower end of said tube portion and in an electrically continuous manner around said tube portion;
• and
• (e) resistance heating said flanges and tube portion by applying electric power to said flanges for distributing electrical power through said flanges and said tube portion to heat said tube portion uniformly around said tube portion.