Most manufacturers use horizontal tempering furnaces to produce tempered glass. As everyone knows, for horizontal tempering furnaces, temperature control has two basic requirements: first, the temperature difference between different parts of the glass surface cannot be too large, that is, uniform heating is required; second, the glass needs to be quickly heated to the required temperature.

　　The control of temperature during tempering is centered around these two core aspects.

　　I. Uniform Heating

　　1. Avoid the temperature difference between the upper and lower surfaces of the glass affecting the tempering effect. Too large a temperature difference between the upper and lower surfaces can easily cause the glass to become uneven, deformed, or even broken. During production, the following two points should be noted: First, the placement of glass in each furnace and the gaps between furnaces should be even; second, to ensure the uniformity and consistency of the roller temperature, avoid the roller temperature between glass plates being too high. If a gap appears longitudinally, this gap should be filled when placing the next furnace of glass.

　　2. When the glass first enters the furnace, the convective heating method should be increased, the upper and lower heat balances should be opened, and the high-temperature hot air circulation system in the furnace should be used for hot air circulation to effectively solve the problem of large temperature differences at various points on the glass.

　　In the latter half of the heating process, the temperature difference at various points on the glass is no longer obvious, and the main focus should be on increasing the heating speed. The various heat balances can be closed until the glass temperature is consistent with the set furnace temperature, and the heating process is completed.

　　3. If uneven edges are encountered on the glass, control can be implemented in two ways: On the one hand, increase the heat balance pressure in the furnace to increase heat convection, and then adjust the furnace's heat balance to reduce the temperature difference between the large central area and the edges of the glass; on the other hand, the heating time of the glass can be appropriately extended, thereby reducing the temperature difference between the center and the edges of the glass.

　　II. Heating Temperature

　　1. The thinner the tempered glass, the higher the heating temperature; the thicker the glass, the lower the heating temperature. Therefore, in terms of tempered glass technology, it is impossible to clearly state which temperature setting is optimal. The choice of temperature largely depends on the quality of the original glass and the process parameters adjusted by the operator. Process parameters can be found online and will not be elaborated here. In actual production, the heating temperature is controlled by adjusting the heating time, and every operator should master the calculation method for the heating time.

　　2. The bottom temperature measured by the heating system is not the roller temperature, but the average temperature of the heating element at the bottom of the tempering furnace after compensating for the heat absorbed by the roller glass. Therefore, the measured temperature is usually higher, slightly higher than the measured upper temperature, so the upper heating temperature is generally set higher than the lower heating temperature.

　　3. Avoid overloading the electric furnace. Under normal circumstances, there is always glass absorbing heat in the heating area of the central heating element of the electric furnace, and there is always glass present in this area. If the heat consumption in a certain area of the electric furnace exceeds the heating effect, the temperature in that area begins to drop until the temperature balance stops. Therefore, once the electric furnace is overloaded, it will cause the glass to break in the cooling section.

　　The above is a summary of the key points of temperature control in horizontal tempering furnaces. For more information, please continue to follow us.