Abstract: Thermal convection currents in the headspace above a body of glass being formed into a continuous sheet of glass while supported on molten metal are controlled to prevent the development of surface distortion patterns in the upper surface of the glass being formed. This is accomplished by establishing a series of small convection cells at least adjacent the upper surface of the glass so that the characteristic convective cooling rate for the glass in the forming chamber is substantially diminished, particularly near the inlet end of the forming chamber.

Abstract: Flat glass is produced by advancing a layer of molten glass along the surface of molten metal while cooling it sufficiently to form a continuous sheet of glass which is lifted upwardly from the surface of a supporting pool of molten metal and conveyed from it for further processing. The molten metal substantially immediately beneath the location at which the glass is lifted upwardly from the pool of molten metal is cooled to a temperature below that of a surrounding molten metal in order to provide for the free release of the formed sheet of glass from the molten metal and to provide for the production of an extremely flat sheet of glass.