Abstract: A method and apparatus for heating glass sheets in preparation of tempering. A furnace (1) is provided with upper and lower convection blasting conduits (11, 14) extending lengthwise of the furnace. The furnace is also provided with upper and lower radiation heating elements (12, 16). The convection heating air is pressurized with a compressor (3), cleaned with a filter (4). The upper convection heating air is heated with air discharged from the furnace in a plurality of separate heat exchangers (7), through which the convection heating air is passed into the upper convection blasting conduits (11). The amount of air discharged from the furnace (1) through the heat exchangers (7) is substantially equal to that blasted into the furnace for convection heating.

Abstract: A method and apparatus for heating glass sheets in preparation of tempering. A furnace (1) is provided with upper and lower convection blasting conduits (11, 14) extending lengthwise of the furnace. The furnace is also provided with upper and lower radiation heating elements (12, 16). The convection heating air is pressurized with a compressor (3), cleaned with a filter (4). The upper convection heating air is heated with air discharged from the furnace in a plurality of separate heat exchangers (7), through which the convection heating air is passed into the upper convection blasting conduits (11). The amount of air discharged from the furnace (1) through the heat exchangers (7) is substantially equal to that blasted into the furnace for convection heating.

Abstract: The invention relates to an air-exhausting and pre-pressing apparatus for laminated glass sheets. In the manufacture of laminated windscreens, the glass sheets are carried on a conveyor in a substantially upright position through a heating tunnel. The suction tubes included in a suction track adjacent to the conveyor are coupled with suction rings surrounding the edges of the laminated glass sheets. A preheating station, a heating station, and a recooling station are set successively to define together a heating tunnel, the conveyor extending through the heating tunnel. The preheating station and the recooling station are linked with each other by at least two air circulation ducts for circulating air from the recooling station to the preheating station and from the preheating station back to the recooling station. The arrangement saves heating energy and achieves a uniform heating and cooling of glass sheets.