초록 ▼

A method for delivering a glass stream having a first inner layer and a second outer layer, including a generally vertical orifice, and delivering glass from a second source such that the glass from the second source provides an outer layer about the glass from the first source as it flows through t

A method for delivering a glass stream having a first inner layer and a second outer layer, including a generally vertical orifice, and delivering glass from a second source such that the glass from the second source provides an outer layer about the glass from the first source as it flows through the orifice. A resistance heated tube assembly is made of platinum or material having similar resistance heating properties and extends from a glass source to an orifice through which the glass flows from a glass source for the inner layer. The tube assembly includes a tube portion having an inlet end that communicates with the source for the outer layer and an outlet end that communicates with the source. The tube portion has an axis positioned at any angle ranging between the horizontal and vertical but preferably has an axis which is more vertical than horizontal. Flanges are secured to the ends of the tube portion, and the flanges are connected to an electric power supply. The cross sectional thickness of the flanges is preferably greater than the thickness of the tube portion. Each flange includes an annular groove adjacent its respective end of the tube portion into which the end of the tube portion extends. The flanges are welded to the tube portion. Flange heater modules surround each end of the tube portion.

대표청구항 ▼

[ What is claimed is:] [1.] 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

[ What is claimed is:] [1.] 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.