Abstract: A glass sheet tempering method and resultant glass sheet are disclosed as being provided by modulated quenching that initially cools the oppositely facing surfaces of a conveyed glass sheet at a first cooling station (14) with a first rate of heat transfer for a finite time to cool the surfaces from tempering temperature to below the strain point without cooling the center of the glass sheet below the strain point. Thereafter the oppositely facing surfaces of the conveyed glass sheet are cooled within a second cooling station (15) at a second rate of heat transfer less than the first rate to initially cool the center of the glass sheet below the strain point without corresponding surface cooling, and thereafter further cools the center and the sruface. The second rate of heat transfer is of a magnitude so that the surface temperature initially increases without going back substantially above the strain point prior to subsequently again cooling.

Abstract: A continuous regenerative tank-type glass melting furnace having a plurality of burner ports along each side in communication with a longitudinally extending plenum. Beneath and extending throughout the length of each plenum is a checkerbrick structure supported upon longitudinally extending arches carried by transverse walls. The walls divide the area beneath the checkerbricks into a plurality of chambers, each chamber being below a corresponding one of the ports. A tunnel joins each chamber to a common manifold connected to a reversing combustion air and exhaust gas system. Each tunnel is provided with a damper for varying its effective cross-sectional area, thereby permitting improved regulation of the flow distribution of exhaust gases and combustion air through the regenerators.

Abstract: A continuous tank-type glass melting furnace containing a bath of molten glass and having a waist section of reduced width whereat a submerged weir extends across the path of the molten glass bath flowing therethrough. The weir is located adjacent the floor of the waist section for modifying the flow path in the lower regions of the molten bath between the refining and conditioning zones of the furnace. Also, a surface barrier and stirrers may be provided in the waist section for improving the homogeneity of the molten bath.

Abstract: A method of and apparatus for directing and regulating the flow of combustion air to opposite ends of the regenerators of a regenerative tank-type glass melting furnace so as to minimize localized overheating and more uniformly heat the checkerworks of the regenerators, thereby improving the operating efficiency and prolonging the useful life thereof. To accomplish these ends, a substantial portion of the combustion air supplied to the regenerators is delivered to their downstream ends while a lesser portion is supplied to their upstream ends by ducts which include valves for cycling and a damper for apportioning the amount of combustion air flowing to opposite ends of the regenerators.