Patent ID: 7127918

Claim:
A method for heating glass sheets in preparation of tempering, said method comprising heating horizontal glass sheets with upper and lower convection blasting and upper and lower radiation heating, pressurizing convection heating air with a compressor and cleaning with a filter and adjusting the widthwise profile of upper convection heating by controlling the amount of convection air to be separately blasted to a plurality of widthwise parallel heating zones, wherein upper convection heating air is heated with air discharged from a furnace in a heat exchanger, through which the convection heating air is delivered into a furnace, the amount of air discharged from the furnace through the heat exchangers is substantially equal to the amount of air blasted into the furnace for convection heating, the widthwise profile of lower convection heating is adjusted by controlling the amount of convection air to be separately blasted to a plurality of widthwise parallel heating zones, and wherein the widthwise profiles of upper and lower convection heating are adjusted with profiling consistently with each other.