Abstract: Dark blue dyed furnace sight glass of soda-lime-silica further containing carbon and oxides of iron and cobalt with substantially no infrared transmission and which sight glass affords a view of details in the melting operation. Other ingredients may include K.sub.2 O, MgO, Al.sub.2 O.sub.3 or ZrO.sub.2.

Abstract: A phototropic multilayered glass sheet incorporating at least two interfacially laminated layers, one layer consisting of a nonphototropic carrier glass, and at least one other layer consisting of a phototropic glass. In manufacture, at least one of the glass streams is characterized by having a viscosity of less than 10.sup.7.6 d PAS at the location where the streams are brought together.

Abstract: The invention provides a method and apparatus for the manufacture of glass film having a thickness not in excess of 0.003 inches and accomplished by drawing the film through a narrow slot-like orifice. The walls of the orifice are defined by an electrically conductive, hot glass resistant metal and electrical currents are introduced into the metal walls of the orifice to effectively maintain the central portions of the orifice walls at a higher temperature than each of the two lateral end walls of the orifice, thereby producing a temperature differential in the drawn film on the order of 40.degree. F. between the edges of the film and the central portions of the film.

Abstract: A relatively thin layer of molten photochromic glass is formed on the surface of a relatively thick molten core glass of greater viscosity than that of the photochromic glass as such core glass is drawn into sheet form. The core glass is selected for its viscosity-temperature characteristics such that the core glass will support the photochromic surface glass during the temperature cycle required for developing the photochromic properties of such surface glass.

Abstract: A nozzle system is disclosed for the production of a wide band of flat plate glass in which the glass flows out of a nozzle orifice of a flat nozzle formed by two nozzle bars. One of the nozzle bars has a nozzle forming portion which is selectively elastically deformable. The other nozzle bar is of rigid construction. Deforming members are provided to selectively deform the one nozzle bar so as to reduce distortions occurring in the plate glass bands. The other nozzle bar is connected to an adjusting member for controlling an overall spacing with respect to the first nozzle bar so as to adjust overall glass thickness. A process computer may be employed to compare measuring values obtained from points along the deformable portion of the one nozzle bar with a model of a desired curvature stored in the computer.

Abstract: A free-falling curtain of molten glass that is uniform in thickness and temperature is formed by flowing the glass over the lip of a forehearth after conditioning the glass in said forehearth. The forehearth is constructed to provide an increasing rate of fall as the glass travels, flows from the furnace through the forehearth and progressively cools. The floor of the forehearth is essentially the mirror image of the viscosity versus temperature curve of the material being treated.Other molten materials that become viscous as they cool can also be treated by the method of my invention to provide a uniform falling curtain of said material.

Abstract: In the manufacture of sheet glass by drawing a ribbon of glass upwardly from a molten glass bath via a meniscus located at the glass surface in the drawing zone, a pool of molten material is contained in the bath beneath the drawing zone by a refractory member and the molten material pool is thermally conditioned to maintain a predetermined temperature profile in at least part of the drawing zone.

Abstract: The invention provides a method and apparatus for the manufacture of glass film having a thickness not in excess of 0.003 inches and accomplished by drawing the film through a narrow slot-like orifice. The walls of the orifice are defined by an electrically conductive, hot glass resistant metal and electrical currents are introduced into the metal walls of the orifice to effectively maintain the central portions of the orifice walls at a higher temperature than each of the two lateral end walls of the orifice, thereby producing a temperature differential in the drawn film on the order of 40.degree. F. between the edges of the film and the central portions of the film.