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 a method and apparatus for bending and tempering or heat-strengthening a bidirecdonally curved glass panel. A heated glass panel is curved in a main bending direction parallel to the advancing direction and in a sagging direction transversely to the advancing direction. Curving in the sagging direction is performed by bending conveyor rolls, the bending of which is effected by turning lever elements bearing-mounted for free rotation on the ends of the conveyor rolls. Between the outer ends of the lever elements is a push rod, whose length is quickly variable by means of an actuator.

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 for heating LowE glass panels in a tempering furnace (1) provided with rollers. LowE glass panels are carried on a conveyor constituted by rollers (2) into the tempering furnace and then the discussed glass panels are set in an oscillating motion within the tempering furnace for the duration of a heating cycle. This is followed by delivering the discussed glass panels into a tempering station (3). In the tempering furnace, the glass panels are heated by means of top and bottom radiation heating elements (4, 5), as well as by top and bottom convection heating elements (6, 7). In the early stage of a heating cycle the top glass surface is subjected to convection heating more powerful than that applied to the bottom surface and in the final stage of a heating cycle the bottom glass surface is subjected to convection heating more powerful than that applied to the top surface.

Abstract: A method for heating LowE glass panels in a tempering furnace (1) provided with rollers. LowE glass panels are carried on a conveyor constituted by rollers (2) into the tempering furnace and then the discussed glass panels are set in an oscillating motion within the tempering furnace for the duration of a heating cycle. This is followed by delivering the discussed glass panels into a tempering station (3). In the tempering furnace, the glass panels are heated by means of top and bottom radiation heating elements (4, 5), as well as by top and bottom convection heating elements (6, 7). In the early stage of a heating cycle the top glass surface is subjected to convection heating more powerful than that applied to the bottom surface and in the final stage of a heating cycle the bottom glass surface is subjected to convection heating more powerful than that applied to the top surface.

Abstract: The invention relates to an assembly in the annealing section of a glass tempering apparatus, comprising a glass sheet supporting rollers and cooling air blow boxes disposed above and below a glass sheet. A blast pressure applied to the bottom surface of a glass sheet may tend to pick up a glass sheet and float the sheet off contact with the rollers. In order to correct the situation without changing the cooling effects on the opposite surfaces of glass, the radiation absorption factor of surfaces below a glass sheet is higher than the absorption factor of surfaces above on the thermal radiation wavelengths of glass. Thus, the blast pressure on a top surface of the glass sheet has been increased with respect to the blast pressure on a lower surface of the glass sheet.

Abstract: The invention relates to a flow barrier in the annealing section of a glass tempering apparatus, said annealing section being provided with glass sheet supporting rollers (7) and cooling air blow boxes (1, 3) are disposed above and below a glass sheet, in addition to which there are, above the glass sheets, "false rolls" (8) in the form of a downward open trough, extending crosswise to the traveling direction of said glass sheets. The purpose of "false rolls" (8) is to increase a pressure applied to the top surface of a glass sheet in order to reduce the risk of a glass sheet becoming afloat. A flow along the trough, which increases towards the ends of the trough, results in a non-uniform tempering. The flow is cut off by fitting the trough with partitions (9) spaced from each other.

Abstract: A method for the prevention of the curving of glass sheets in the roller-equipped furnace of a horizontal tempering plant utilizes a substantially turbulent air flow over the upper surface of the glass sheet for intensifying the convection heat action applied to the upper surface of the glass sheet. The furnace is fitted with perforated pipes which are connected to a source of compressed air for blowing horizontal air jets above the upper surface of the glass sheet.