Corning Incorporated
Apparatuses and methods for continuous production of glass tubing

Abstract:

An apparatus for producing composite glass tube with a plurality of glass layers includes a plurality of cylindrical containers of increasing inner dimensions concentrically arranged and stationary. Each cylindrical container includes a side wall, bottom wall, and a delivery ring. Adjacent cylindrical containers define an annular chamber, a flow control region, and an annular flow channel therebetween. The apparatus includes at least one flow control valve positioned in the flow control region and translatable relative to the adjacent cylindrical containers. Translation of the flow control valves relative to the cylindrical containers is operable to change an impedance to flow of molten glass through the flow control region, thereby modifying an overall flow rate or circumferential distribution of molten glass from the cylindrical containers. Systems and methods for producing composite glass tube using the apparatus are also disclosed.