A tempering furnace for a glass sheet has a conveyor for the glass sheet, and first convection blow means over the conveyor to heat the glass sheet by hot air jets blown onto its top surface. With second convection blow means, pressurized air external to the tempering furnace may be led to second blow nozzles from which air is discharged as jets towards the bottom surface of the glass sheet. The heating effect of the air jets of the first convection blow means onto the glass sheet is adjustable by adjusting the feeding of electric current to electric elements inside blow enclosures, and the heating effect onto the glass sheet of the jets discharging from the second blow nozzles is adjustable by adjusting the blow pressure of feed pipes.

Smooth, heat-treated glass fragments are created by placing a plurality of heat-treated glass fragments into a tumbling or vibrating apparatus. Each heat-treated glass fragment is formed from glass that has been heated to a temperature of at least 1000° Fahrenheit and rapidly cooled to a temperature below 800° Fahrenheit. The plurality of glass fragments is then tumbled or vibrated for a predetermined period of time such that surfaces of the heat-treated glass fragments are smoother than prior to tumbling. The glass fragments are thereafter removed from the tumbling apparatus, resulting in smoothed, heat-treated glass fragments that have a slightly rounded, bead like-shape and are suitable for direct handling without hand protection. The glass fragments as are able to be provide radiant heat in the temperature range of 400° to 800° Fahrenheit. This temperature range and the use of the heat-treated glass fragments provides for a clean burning fire that virtually eliminates any soot and carbon monoxide while burning.

Smooth, heat-treated glass fragments are created by placing a plurality of heat-treated glass fragments into a tumbling or vibrating apparatus. Each heat-treated glass fragment is formed from glass that has been heated to a temperature of at least 1000° Fahrenheit and rapidly cooled to a temperature below 800° Fahrenheit. The plurality of glass fragments is then tumbled or vibrated for a predetermined period of time such that surfaces of the heat-treated glass fragments are smoother than prior to tumbling. The glass fragments are thereafter removed from the tumbling apparatus, resulting in smoothed, heat-treated glass fragments that have a slightly rounded, bead like-shape and are suitable for direct handling without hand protection. The glass fragments as are able to be provide radiant heat in the temperature range of 400° to 800° Fahrenheit. This temperature range and the use of the heat-treated glass fragments provides for a clean burning fire that virtually eliminates any soot and carbon monoxide while burning.

A method for controlling discharging of a glass plate in a glass plate tempering technology process is provided. After a glass plate is fed into a heating furnace, a monitoring unit monitors and performs filtering on a working parameter of a heating element in real time, and then transmits the filtered working parameter to a control unit. The control unit compares the filtered working parameter with a specified threshold. After the working parameter reaches a maximum value or a minimum value, and then reaches the specified threshold during a subsequent change, the control unit sends an instruction to a drive mechanism. The drive mechanism acts to move the glass plate out of the heating furnace directly or after a time delay, so as to complete a glass plate heating process. The present disclosure changes a conventional time-based control method, reduces energy consumption, and improves quality of a tempered glass.

A method for controlling discharging of a glass plate in a glass plate tempering technology process is provided. After a glass plate is fed into a heating furnace, a monitoring unit monitors and performs filtering on a working parameter of a heating element in real time, and then transmits the filtered working parameter to a control unit. The control unit compares the filtered working parameter with a specified threshold. After the working parameter reaches a maximum value or a minimum value, and then reaches the specified threshold during a subsequent change, the control unit sends an instruction to a drive mechanism. The drive mechanism acts to move the glass plate out of the heating furnace directly or after a time delay, so as to complete a glass plate heating process. The present disclosure changes a conventional time-based control method, reduces energy consumption, and improves quality of a tempered glass.

A strengthened glass sheet product as well as process and an apparatus for producing the product. The process comprises cooling the glass sheet by non-contact thermal conduction for sufficiently long to fix a surface compression and central tension of the sheet. The process results in thermally strengthened glass sheets having improved breakage properties.

A strengthened glass sheet product as well as process and an apparatus for producing the product. The process comprises cooling the glass sheet by non-contact thermal conduction for sufficiently long to fix a surface compression and central tension of the sheet. The process results in thermally strengthened glass sheets having improved breakage properties.

A glass tempering furnace and a method for heating a glass sheet. The glass sheet is heated in the glass tempering furnace by blowing heating air on the top surface of the glass sheet, and the blowing distance of the heating air from the top surface of the glass sheet is adjusted.

A glass tempering furnace and a method for heating a glass sheet. The glass sheet is heated in the glass tempering furnace by blowing heating air on the top surface of the glass sheet, and the blowing distance of the heating air from the top surface of the glass sheet is adjusted.

The present invention relates to a method for manufacturing tempered glass and, more specifically, to a method for manufacturing alkali-free glass which has the thickness of 2.0 mm or less into tempered glass by means of heat treatment and surface treatment using fluosilicic acid. To this end, the present invention provides a method for manufacturing tempered glass, the method comprising: a preparation step for preparing alkali-free glass; a surface treatment step for surface-treating the alkali-free glass by means of a surface treatment solution comprising fluosilicic acid and thereby generating on the surface of the alkali-free glass a porous SiO.sub.2-rich layer of which the coefficient of thermal expansion (CTE) is smaller than the CTE of the inner part of the alkali-free glass; and a heat treatment step for heat-treating the alkali-free glass that has been surface-treated and thereby generating compressive stress on the surface of the alkali-free glass.