Patent ID: 8006517

Claim:
A method for forming sheet glass using an apparatus, wherein the apparatus includes an inflow pipe for delivering molten glass, a trough for receiving molten glass that has sides attached to a wedged shaped sheet forming structure that has downwardly sloping sides converging at the bottom of the wedge such that a glass sheet is formed when molten glass flows over the sides of the trough, down the downwardly sloping sides of the wedged shaped sheet forming structure and meets at the bottom of wedge, and wherein the method comprises the steps of: providing a downcomer pipe connected to an end of the inflow pipe opposite the trough, wherein a bottom end of the downcomer pipe is located at or below a glass free surface in the inflow pipe and the downcomer pipe and the inflow pipe have a size and shape; and maintaining a glass temperature at the free surface above a glass liquidus temperature with at least one heater located at the top of the inflow pipe and/or the bottom of the downcomer pipe in an area of the free surface.