Most tempering furnace manufacturers use continuous tempering furnaces to temper ordinary glass. In terms of temperature control using a continuous tempering furnace , there are basically two basic requirements. First, the temperature of each part of the glass surface must not differ too much, that is, to achieve uniform heating. Second, the glass must be quickly heated to the required temperature. .
The temperature control during the tempering process is based on these two core aspects.
First, even heating
1. To avoid the influence of the temperature difference between the upper and lower surfaces of the glass on the tempering effect of the glass. If the temperature difference between the upper and lower surfaces is too large, it will easily cause the unevenness, deformation and even breakage of the glass. In the production process, we have to do the following two points: First, the placement of the glass in each furnace and the interval time between the furnaces. Uniform; then, in order to ensure the uniformity and consistency of the roller temperature, to avoid the roller temperature between the glass plates being too high, if there is a gap in the vertical direction when the film is placed, this gap must be filled when the glass is placed in the furnace.
2. When the glass just enters the furnace body, the convection heating method should be increased at this time, the upper and lower thermal balance should be turned on, and the high temperature hot air circulation system in the furnace can be used to circulate the high temperature air in the furnace. Point temperature difference problem.
In the second half of the heating, the temperature difference between the various points of the glass is not obvious, and the heating speed should be mainly increased. Each thermal balance can be turned off until the glass temperature is consistent with the set furnace temperature, and the heating process is ended.
3. If the convexity and concaveness of the glass edge is encountered, we can control it from two aspects. On the one hand, it can increase the heat balance pressure in the furnace and increase the heat convection, thereby adjusting the heat balance in the furnace to reduce the middle and edge of the large area glass. On the other hand, the heating time of the glass can be prolonged appropriately, and the temperature difference between the middle and the edge of the glass can also be reduced.
Second, the heating temperature
1. The thinner the tempered glass, the higher the heating temperature, and the thicker the glass, the lower the heating temperature. Therefore, in the tempered glass process, it cannot be clearly specified which temperature setting is the best. To a great extent depends on the quality of the original glass and the process parameters adjusted by the operator. You can find the process parameters on the Internet, I will not describe them here. In actual production, the adjustment of the heating temperature is mainly achieved by adjusting the heating time. The basic calculation method of the heating time should be mastered by each operator.
2. The bottom temperature measured by the heating system is not the roller temperature, but the average temperature after the heating element at the bottom of the tempering furnace compensates the heat absorbed by the roller glass. due to this reason. The measured temperature is generally higher and higher than the measured upper temperature, so generally the upper heating is set higher than the lower heating temperature setting.
3. Avoid the overload of the electric furnace. Under normal operating conditions, in the heating area of the central heating element of the electric furnace, there is always glass that absorbs heat. There is always glass in this area of the electric furnace. The heat consumption in this area exceeds the heating effect, and the temperature in this area starts to decrease until the temperature is balanced. Therefore, once the electric furnace is overloaded, it will cause the glass to break in the cooling section.
The above is the basic requirement for temperature control of the continuous tempering furnace when tempering glass. I hope that everyone can produce according to the above when operating, and I hope it will be helpful to everyone.
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