SU499233A1 - The method of annealing the glass in Lera immediately after molding - Google Patents

Description

one

A method of annealing glass in a lera is known. Immediately after molding, it includes equalizing the temperature of the glass in the loading zone of the lehr, controlled cooling by convection and radiation in the critical cooling zone, and forced cooling in the discharge part of the lehr. In a known method, heated pelvis feeds with a closed-loop recirculation cycle into separate zones are used (and the temperature of the gases in each area is individually controlled, with both heating and cooling being carried out predominantly by convection.

The disadvantage of this method is the considerable time spent on equalizing the temperature of the glass in the process of heating and in the process of cooling due to the low TB glass conductivity.

In order to intensify the annealing process and improve the quality of the beets, the temperature equalization of the glass in the boot zone of the lehr is carried out by supplying gases heated to temperatures exceeding the glass temperature by less than 50 ° C, gases are produced at the end of the critical cooling zone, and heat extraction in the zone of critical cooling and in the discharge part of the lehr is carried out with the help of radiation coolers.

Heated to a temperature exceeding the glass temperature of not less than 50 ° C, the gases entering the boot part of the lehr, provide temperature equalization

glass throughout the volume while creating a thermal gas curtain in the zone of responsible cooling, which completely prevents the heat from being removed from the glass by convection.

In this case, the glass in the zones of responsible and rapid cooling is cooled by radiation with the help of radiation coolers. Since glass is a partially transparent material and has a high integral emissivity, heat is taken not only from the surface, but due to the process of multiple re-radiation throughout the volume. This allows for the same temperature gradients in thickness, i.e., without degrading the quality of the glass, to achieve a significant (not less than 7 times) increase in the rate of annealing of the glass at the critical cooling stage.

25

At the end of the Responsible Cooling zone, heated gases are sucked out and the glass enters the flow of cold gases, which move towards the glass from the discharge end of the lehr. It provides in

rapid cooling zone combined cooling and convection cooling process.

The drawing shows data on the maximum cooling rate at the critical cooling stage, both by convection and by radiation. Data is given for 4 mm thick glass. The maximal rate of cooling of the pane by radiation is at least a factor of higher than the rate of convection cooling at the same stage of annealing. At the stage of rapid cooling (below 340 ° C), the rate of radiative cooling is initially close to the rate of conventional cooling, and then rapidly increases. In this case, the cooling rate at the last stage of annealing with the use of radiation-convection cooling can be increased by 30% compared with pure convection cooling.

Claims (1)

Formula invented and The method eliminates glass in the lera immediately after molding, including equalizing the temperature of the glass in the loading area of the leer, controlled cooling by convection and radiation in the area of the responsible cooling, and forced cooling in the unloading part of the lera, that, in order to intensify the annealing process and improve the quality of the glass, the temperature of the glass in the leer loading zone is equalized by applying heat to the temperature exceeding the glass temperature by at least 50 ° C, gases, etc. They are sucked to the end of the zone of responsible cooling, and the selection of Tenla in the zone of responsible cooling and the unloading part of the lehr is carried out using radiation coolers. AH g rad / min LH 200 30ff 00 500 BOO 700 T, (.