Application of 6000 series frequency converter in tempering furnace

With the rapid development of science and technology, the use of tempered glass is more and more extensive, and its products are more and more abundant. In fact, tempered glass has already become the largest member of the glass deep-processing family. Tempered glass has become an indispensable important material in human life. .

I. Overview

With the rapid development of science and technology, the use of tempered glass is more and more extensive, and its products are more and more abundant. In fact, tempered glass has already become the largest member of the glass deep-processing family. Tempered glass has become an indispensable important material in human life. . Tempered glass obtains a large permanent stress through heating and quenching, so it is also called prestressed glass. If you want to eliminate this stress, you can only heat the glass again to near softening.

2. Working principle

1. The technological principle of glass tempering: the ordinary high-quality flat glass after cutting, grinding and washing is sent to the tempering furnace, and through heating (680℃~715℃) and quenching, a large permanent stress is generated in the glass— The surface is compressive stress, and the internal is tensile stress, that is, the glass produces a uniform and regularly distributed internal stress, thereby improving the strength and thermal stability of the glass.

Its production process is:

Original glass → Inspection → Cutting → Breaking → Washing → Drying → Tempering → Inspection → Packaging → Storage

The tempering process is:

Insertion → heating → quenching → slow cooling → unloading

2. Main features of tempered glass

1) High mechanical strength: When the tempered glass is subjected to external pressure such as load pressure, bending or impact, its stressed surface is subjected to compressive stress, while the other surface is subjected to tensile stress. As the load increases, this tensile stress is gradually reduced by the original compressive stress on the tempered glass surface, and it does not become a tensile stress until it is completely offset. Because the compressive strength of the glass is almost 10 times greater than the tensile strength, the glass not only strengthens the surface after tempering, but also transfers its weak links. Therefore, the compressive strength and bending strength of tempered glass are generally increased by 4 to 5 times, while the impact strength can be increased by 5 to 8 times.

2) Good thermal stability: The improvement of the thermal stability of tempered glass is just like the increase of mechanical strength, and it is also related to the size and distribution of internal stress. When the glass surface is rapidly heated, the inner layer is still in a cooling state, so that the heated surface is under compressive stress, and the inner layer is under tensile stress. When the temperature difference is too large and the tensile stress exceeds the tensile strength of the glass, the glass bursts. The original compressive stress of the tempered glass surface layer can offset some of the thermal expansion and relieve the tensile stress of the inner layer, so the thermal stability of the tempered glass can be increased by 1.5 to 2 times.

3) Strong safety: The cracking of the glass is caused by the crack defect as the starting point, which exceeds the tensile strength. Although the weak point (tensile stress zone) of tempered glass is in the center, there is usually no micro-crack defect, but under the conditions of high-speed impact and internal stones, a crack starting point will also be formed in the tensile stress layer, and the crack will be under the action of tensile stress It expands and spreads rapidly around, forming a group with many cracks and different sizes. Moreover, because the tempered glass bursts suddenly under the closed condition of compressive stress, the fragments are small honeycomb particles when broken, and they are uniform and non-sharp mesh particles, which are not easy to hurt people, so they have good safety performance and are safe A kind of glass.

3. System configuration

1. Composed of loading table, heating area, tempered cooling area, unloading area, control table and electric control cabinet. The loading table, heating area, cooling area and unloading table are driven by the cycloid pin wheel reducer to drive the chain drive. The tempered cooling area is rapidly cooled by the blower. The air duct is provided with upper and lower air grids to control the yield rate of glass tempering.

2. Electrical control system for horizontal rail tempering furnace

The electrical system of the horizontal rail tempering furnace is mainly composed of the loading table drive motor, heating zone drive motor, cooling zone drive motor, unloading table drive motor, heating and cooling fan motor, monitoring computer (HMI), PLC, inverter and various Field instrument sensor composition. The fully automatic horizontal orbital tempering furnace has manual, semi-automatic and automatic control methods. The start, stop and parameter setting of each unit of the tempering furnace are all done through HMI. At the same time, the HMI monitors the running status of the entire system. Alpha frequency converters play an important role as power drive components in the entire control system.