Abstract: A method for tempering substantially flat glass sheets. A glass sheet is heated to a tempering temperature and quenching is conducted by blasting cooling air to both surfaces of the glass sheet. The quenching of a top surface and a bottom surface of the glass sheet's both side lanes is commenced earlier or is performed at the early stage of quenching more effectively than the quenching of a top surface and a bottom surface of the glass sheet's middle lane. As a result, the compressive stress required for a desired tempering degree is established on both surfaces of the side lanes earlier than on both surfaces of the middle lane. In order to achieve this, the cooling air enclosures above and below a glass sheet are provided with a subarea of weakened cooling effect.

Abstract: A method and an apparatus for tempering glass sheets. A glass sheet is heated to a tempering temperature and quenching is conducted by blasting cooling air to both surfaces of the glass sheet. The quenching of a top surface and a bottom surface of the glass sheet's both side portions is commenced earlier or is performed at the early stage of quenching more effectively than the quenching of a top surface and a bottom surface of the glass sheet's intermediate portion. As a result, the compression stress required for a desired tempering degree is established on both surfaces of the side portions earlier than on both surfaces of the intermediate portion. In order to achieve this, the cooling air enclosures above and below a glass sheet are provided with a subarea of weakened cooling effect.

Abstract: A method and an apparatus for tempering glass sheets. A glass sheet is heated to a tempering temperature and quenching is conducted by blasting cooling air to both surfaces of the glass sheet. The quenching of a top surface and a bottom surface of the glass sheet's both side portions is commenced earlier or is performed at the early stage of quenching more effectively than the quenching of a top surface and a bottom surface of the glass sheet's intermediate portion. As a result, the compression stress required for a desired tempering degree is established on both surfaces of the side portions earlier than on both surfaces of the intermediate portion. In order to achieve this, the cooling air enclosures above and below a glass sheet are provided with a subarea of weakened cooling effect.

Abstract: The invention relates to a method of heating a glass sheet for tempering. It comprises conveying the glass sheet on top of rollers in a roller-hearth furnace, heating the glass sheet in the roller-hearth furnace to a transfer temperature at which the glass sheet is transferred into an air support furnace. The glass sheet, while resting on an air cushion, is carried on an air support table and the glass sheet is heated in the air support furnace to a tempering temperature. The transfer temperature is not lower than 620° C. and not higher than 675° C. and the tempering temperature is not lower than 650° C. and not higher than 720° C.

Abstract: The invention relates to a method of heating a glass sheet for tempering. It comprises conveying the glass sheet on top of rollers in a roller-hearth furnace, heating the glass sheet in the roller-hearth furnace to a transfer temperature at which the glass sheet is transferred into an air support furnace. The glass sheet, while resting on an air cushion, is carried on an air support table and the glass sheet is heated in the air support furnace to a tempering temperature. The transfer temperature is not lower than 620° C. and not higher than 675° C. and the tempering temperature is not lower than 650° C. and not higher than 720° C.

Abstract: An apparatus for conveying glass sheets on an air support table, which is included in a heating furnace and provided with blast apertures and exhaust apertures, and in which the blast apertures are connected to a plenum chamber present underneath the air support table. The exhaust apertures are connected to exhaust passages present inside the table. The exhaust passages have at least one of their ends provided with a gate/gates capable of being opened and closed, by means of which the flow of air from the exhaust passages' ends adjacent to the gate/gates can be completely or partially blocked.

Abstract: An apparatus for tempering glass sheets. A glass sheet is heated to a tempering temperature and quenching is conducted by blasting cooling air to both surfaces of the glass sheet. The quenching of a top surface and a bottom surface of the glass sheet's both side lanes is commenced earlier or is performed at the early stage of quenching more effectively than the quenching of a top surface and a bottom surface of the glass sheet's middle lane. As a result, the compressive stress required for a desired tempering degree is established on both surfaces of the side lanes earlier than on both surfaces of the middle lane. In order to achieve this, the cooling air enclosures above and below a glass sheet are provided with a subarea of weakened cooling effect.

Abstract: A method for tempering substantially flat glass sheets. A glass sheet is heated to a tempering temperature and quenching is conducted by blasting cooling air to both surfaces of the glass sheet. The quenching of a top surface and a bottom surface of the glass sheet's both side lanes is commenced earlier or is performed at the early stage of quenching more effectively than the quenching of a top surface and a bottom surface of the glass sheet's middle lane. As a result, the compressive stress required for a desired tempering degree is established on both surfaces of the side lanes earlier than on both surfaces of the middle lane. In order to achieve this, the cooling air enclosures above and below a glass sheet are provided with a subarea of weakened cooling effect.

Abstract: An apparatus for conveying glass sheets in an air support table, which is included in a heating furnace and provided with blast apertures and exhaust apertures, and in which the blast apertures are connected to a plenum chamber present underneath the air support table. The exhaust apertures are connected to exhaust passages present inside the table. The exhaust passages have at least one of their ends provided with gate/gates capable of being opened and closed, by means of which the flow of air from the exhaust passages' ends adjacent to the gate/gates can be completely or partially blocked.

Abstract: The mould construction for bending glass sheets includes a framework and support plates on vertical planes, the curvature of the upper edge of the plates essentially corresponding to the desired bending curvature of the glass sheet. On the upper edges of the support plates are slots and pipes forming the mould surface are positioned in the slots. The slots are dimensioned with play with respect to the pipes, but to lock the upward movement of the pipes from the slots. The support plates are supported on the framework in such a way that one end of the mould surface is lower than the other end. The difference in height, that is, the inclination of the mould surface, is dimensioned so as to effect the resting of the edge of the glass sheet placed on the mould against the end stoppers during the bending stage.