The difference between forced convection glass tempering furnace and ordinary glass tempering furnace

At present, the forced convection glass tempering furnace has been widely recognized in the industry, and compared with ordinary tempering furnaces, it is gradually gaining the favor of users. So, what should we pay attention to when choosing a tempering furnace? Today, we will introduce to you the differences between forced convection tempering furnaces and ordinary tempering furnaces?

1. Differences in heating technology for glass tempering furnaces

Forced convection glass tempering furnace: High temperature fans are installed on the upper and lower parts of the forced convection glass tempering furnace, which can accurately control the furnace temperature, making the heating of the upper and lower parts more uniform, truly achieving simultaneous operation of the upper and lower parts. The forced convection tempering furnace can be adjusted according to the actual needs of users, which is more in line with production needs. From design drawings to equipment installation and debugging, to later maintenance, it is very convenient.

Ordinary glass tempering furnace: Ordinary glass tempering furnaces all use radiation heating technology. In a radiation heating furnace, the heat absorbed on the surface of the glass mainly comes from the thermal radiation of the heating element, as well as a very small part from convective heat transfer, and a small part of convective heat transfer is caused by the relative movement of the glass and the hot air inside the furnace during its movement.

2. Differences in Convection Methods of Glass Tempering Furnaces

Forced convection glass tempering furnace: The convection method is directly related to the effectiveness of product use and is also the key to cost control. At present, there are two types of convection methods for forced convection tempering furnaces: upper semi convection and full convection.

2.1. Upper semi convective type: only forced convection heating is used for upper heating, while conventional radiation heating is used for lower heating. The heating temperature in the upper part is higher, making it easy to achieve uniform heating up and down. Suitable for tempering high-quality glass and various online and offline coated glass.

2.2. Full convection method: Compared with the traditional structure that uses an enlarged balance tube to enhance upper convection, although a mixed heating method of convection and radiation is used, there are still differences. The full convection method uses upper heating and lower forced convection heating, fundamentally solving a series of heating problems caused by the difference in radiation rates between the upper and lower layers of Low-E glass. In addition, some forced convection tempering furnaces on the market currently use smaller high-temperature convection fans, fewer convection fans, smaller side flow boxes of fans, higher fluid resistance, incomplete convection, and cross flow, which can affect the hot air circulation, reduce heating efficiency, and lower glass quality. After long-term use, the box will deform and other problems will occur.

Ordinary glass tempering furnace: uses radiation heating technology. In ordinary radiation furnace, the heat on the surface of the glass is mainly absorbed by the thermal radiation of the heating element, while convective heat transfer accounts for a small proportion. Due to the relative movement of glass with the hot air in the heating furnace during its movement, a convective heat transfer is formed. Therefore, the heat transfer in the upper layer of the heating furnace is relatively single, and the radiation heat transfer on the surface of the glass by the heater occupies a considerable proportion. Due to the relative movement between glass and the heated air during its movement, the convective heat transfer caused is very limited. Therefore, the heat transfer in the upper layer of the glass tempering furnace is related to the temperature of the heater surface and the emissivity (or blackness) of its glass.

3. Differences in heating systems

Forced convection glass tempering furnace: using "nickel soldering wire", its heating wire has the characteristics of uniform heating, good stability, long service life, and fast heating.

Ordinary glass tempering furnace: Many tempering furnaces use ordinary radiation furnace heating wires.

4. Differences in high-temperature convection curve control

Forced convection glass tempering furnace: The heating curve can be adjusted freely, and multiple heating zones can be set in any direction of the furnace width. Each heating zone is independently controlled, and different heating temperature curves can be flexibly generated.

Ordinary glass tempering furnace: The high-temperature convection curve control reflects the temperature control ability of the heating area of the furnace body. If the glass heating is uneven, it is easy to cause unqualified tempering and furnace explosion.

5. Differences in ceramic roller tracks

Forced convection glass tempering furnace: Select materials with smooth ceramic roller surface and good high-temperature resistance.

Ordinary glass tempering furnace: The ceramic roller of the ordinary tempering furnace is made by combining quartz and ceramics, which has good heat resistance and thermal stability. The heating and cooling process of the glass is carried out on the ceramic roller.

6. Differences in supporting auxiliary systems

Forced convection glass tempering furnace: Industrial electrical appliances and temperature module control are used to ensure the reliability of the system. The all nickel chromium stainless steel furnace liner and box material are controlled by industrial electrical appliances and temperature control modules to ensure the reliability of the system. The use of a tempering section wind pressure auxiliary control system reduces the dependence on operator experience, improves usage efficiency, and reduces the defect rate caused by human factors.

Ordinary glass tempering furnace: The selection of electrical products should be at a lower level, and the internal materials also vary greatly.

In summary, the difference between forced convection tempering furnace and ordinary tempering furnace can be distinguished from the six points mentioned above in the article. We hope it will be helpful to you! Of course, when choosing between the two, it is necessary to determine based on the market positioning of the product.