With the continuous improvement of technological level, the tempering technology of glass has also been elevated to a higher level. Glass toughening technology originated around 1930 and has a development history of over 80 years, with significant improvements in its toughening technology. Relatively speaking, the tempering of glass during the glass processing process belongs to the subsequent process, and any losses or defective products that occur during the tempering stage will result in huge cost losses. Therefore, the tempering process should be taken seriously.
1. Glass toughening method
The so-called glass tempering is the process of heating and rapid cooling the glass to improve its mechanical properties. The principle is to quickly use cooling technology after heating the glass to make it have sufficient tensile stress and generate corresponding compressive stress on the entire surface. The tempering process effectively achieves the safety, high strength, and thermal stability characteristics required for glass, which can meet daily needs. The methods of glass tempering are divided into two types: physical tempering and chemical tempering. The principle of physical tempering is to heat the glass material using a heat transfer medium and rapidly cool it in the cooling medium. The methods can be divided into the following types based on different media:
1) Gas medium tempering method: The so-called gas medium generally uses air as the heat transfer medium, and at this time, the tempering furnace needs to reach a temperature of 600~700 ℃. Then cool the glass by blowing in air. Although this cooling method greatly reduces cooling costs, it has slow cooling speed and low cooling efficiency, which can easily lead to glass deformation.
2) Liquid medium tempering method: As the name suggests, liquid medium tempering method is the use of liquid to toughen and cool heated glass.
3) Particle tempering method: Using smaller alumina particles to cool the heated and softened glass particles. The cooling effect of this method is very good, and the quality of glass toughening is high, but the relative cost is also high.
Compared to physical methods, there are also chemical tempering methods. This method mainly involves changing the surface composition of glass through chemical methods to increase the compressive stress of glass and improve its mechanical properties. The glass tempered by this method is not prone to deformation and has good quality. But the efficiency is low and the cost is high.
2.Energy Saving and Key Technologies of Glass Tempering Equipment
With the improvement of technological level, glass toughening technology has developed rapidly. The widely used tunnel type tempering furnace is currently the most popular one. This type of tempering furnace has been widely sought after due to its high efficiency in heating larger glass. The tempering furnace is mainly composed of a front-end loading platform, a heating area, a tempering cooling area, a unloading platform, an operating platform, and an electrical control device. The heating method mainly adopts the form of full electric radiation heating, that is, the heating source mainly comes from the electric heating elements in the furnace. This requires controlling the distance between the heating element and the glass plate that needs to be heated, otherwise it can easily cause heat waste and energy waste. Based on the above, it is concluded that the energy consumption waste of glass toughening mainly occurs in the heating and cooling zones.
2.1 Adopting multi-station heating technology inside the glass tempering furnace
The application of multi station heating technology not only has significant energy-saving effects, but also greatly avoids the phenomenon of furnace explosion in the tempering furnace. The so-called glass tempering furnace station refers to the process of having glass of the same specification swing back and forth in their respective areas along the length direction of the furnace body, completing the preset time in their respective areas, and moving to the next station after heating the glass to the corresponding requirements. Although the manufacturing processes and structures of various tempering furnaces vary, there is not much difference in the required temperature for heating the glass out of the furnace. For multi-station tempering furnaces, it can greatly reduce the temperature difference inside the furnace, avoid the occurrence of glass cracking in the furnace, reduce heat loss, and have a great promoting effect on achieving energy conservation and emission reduction.
2.2 Adopting frequency conversion technology
Frequency conversion technology is often applied in fan blowing and ceramic roller drive, with relatively significant energy-saving effects. The blower using frequency conversion technology can not only quickly meet the requirements of cooling zone air volume during the glass tempering process, but also generate sufficient air pressure. This rapid cooling automatic air pressure and air volume regulation greatly saves electricity and reduces energy loss. The optimized matching of fan air volume, air pressure, and ceramic roller speed also improves the quality of glass toughening.
This article is excerpted from architectural glass and industrial glass. If reprinted, please indicate the source.
Slightly modified in this article
