WO2024092951A1

WO2024092951A1 - Glass tempering heating furnace

Info

Publication number: WO2024092951A1
Application number: PCT/CN2022/136702
Authority: WO
Inventors: 解冰寒; 任志恒; 付超
Original assignee: 松山湖材料实验室; 中科卓异环境科技(东莞)有限公司
Priority date: 2022-11-01
Filing date: 2022-12-05
Publication date: 2024-05-10
Also published as: CN115650567B; CN115650567A

Abstract

The present application relates to the field of glass tempering, and relates to a glass tempering heating furnace. The heating furnace comprises a preheating section furnace body, a heating section furnace body, and a soaking section furnace body. In an advancing direction of glass, the preheating section furnace body is divided into multiple sections, and each section is provided with a smoke extraction port and a smoke injection interface; the smoke extraction port is used for extracting smoke of the preheating section; the smoke injection interface is used for feeding the extracted smoke into the furnace body; the heating section furnace body is provided with a plurality of infrared burners, and the infrared burners are porous medium burners; smoke of the heating section furnace body is extracted by means of the smoke extraction port of the preheating section, and the extracted smoke is fed into the preheating section furnace body by means of the smoke injection interface; a plurality of air ducts are arranged in the soaking section furnace body and are used for generating horizontally parallel airflow on the upper surface and the lower surface of the glass. The heating furnace in the present application can quickly and uniformly heat glass, can be suitable for tempering heating of common glass, and is particularly suitable for tempering requirements for coated glass and Low-E glass.

Description

Glass tempering heating furnace

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to the Chinese patent application with application number 202211358216.6 and name “Glass Tempering Heating Furnace” filed with the State Intellectual Property Office of China on November 1, 2022, the entire contents of which are incorporated by reference into this application.

Technical Field

The present application relates to the field of glass tempering, and in particular to a glass tempering heating furnace.

Background technique

As a transparent or translucent amorphous material, glass exhibits unique properties in the heat transfer process. Glass has a structure that is ordered in the short range and disordered in the long range. Glass is transparent or translucent to visible light and infrared light. When it receives external heat, it generates higher frequency electromagnetic radiation energy inside. This heat transfer process is called photon heat conduction. Photon heat conduction of transparent glass at room temperature accounts for about 10% of the total heat transfer. As the temperature rises, the effect of photon heat conduction increases, and volume radiation occurs inside the glass.

Ordinary transparent glass has a high emissivity and can absorb thermal radiation energy very well. Low-E glass can be made by coating the surface of ordinary glass with a film with low emissivity. The most notable characteristics of Low-E glass are high reflectivity for far-infrared radiation, low emissivity for near-infrared radiation, and high transmittance for visible light. This means that after Low-E glass is used in a building, the visible light part of the sunlight can be transmitted, playing a role in lighting, while most of the infrared radiation that can produce thermal effects is blocked outside the window. Due to the surface modification of Low-E glass, many technical problems will arise during the tempering and heating process.

Compared with ordinary glass, tempered glass is a safety glass. Tempered glass is actually a prestressed glass. In order to improve the strength of the glass, chemical or physical methods are usually used to form compressive stress on the glass surface. When the glass is subjected to external force, the surface stress is first offset, thereby improving the bearing capacity and enhancing the glass's own resistance to wind pressure, cold and heat, impact, etc.

Glass tempering is divided into "physical tempering" and "chemical tempering".

Physical tempering is a process in which ordinary flat glass is heated in a heating furnace to a temperature close to the softening temperature of the glass (600°C), and its internal stress is eliminated through its own deformation. The glass is then removed from the heating furnace and high-pressure cold air is blown to both sides of the glass with a multi-head nozzle to cool it quickly and evenly to room temperature, thereby producing tempered glass.

Chemical tempering improves the strength of glass by changing the chemical composition of the glass surface. It is generally tempered by ion exchange. The method is to immerse silicate glass containing alkali metal ions into molten lithium (Li ⁺ ) salt, so that the Na ⁺ or K ⁺ ions on the surface of the glass are exchanged with Li ⁺ ions, and a Li ⁺ ion exchange layer is formed on the surface. Since the expansion coefficient of Li ⁺ is smaller than that of Na ⁺ and K ⁺ ions, the outer layer shrinks less and the inner layer shrinks more during the cooling process. When cooled to room temperature, the glass is also in a state where the inner layer is under tension and the outer layer is under compression. The effect is similar to that of physical tempered glass.

The present application discusses the equipment involved in physical tempering, namely, a tempering heating furnace.

From the perspective of heat transfer, the heat transfer processes involved in the heating process of glass in the tempering furnace include "radiation heat transfer", "convection heat transfer" and "heat conduction".

Radiative heat transfer: Radiation is everywhere. When a piece of cold glass enters the heating furnace of the glass tempering furnace, various heating elements, furnace wall insulation materials, and ceramic rollers all emit radiant heat to heat the glass. Waves have two forms of "absorption + penetration" for the heated object. Only absorption can heat the object. From the spectral curve of the glass, due to the composition, the infrared transmission curve is in the form of "peaks and valleys", not a straight line. The corresponding "valley" is the wavelength range that the glass can absorb, and the wavelength that can be absorbed is not one.

Figure 12 is only the infrared transmission curve of a certain type of glass. Different types of glass have different curves. This requires that during the tempering and heating process of the glass, the wavelength of the wave radiated outward by the heat source should be a "wide-band" wave, covering the absorption wavelengths corresponding to different types of glass as much as possible. In fact, it also requires that the temperature of the heat source can be both very high and relatively low (compared to the resistance wire).

Convective heat transfer: In the production process of tempered glass, there are several types of convection heat transfer.

1. Natural convection: When there is a temperature difference in the furnace, the air flows naturally. When cold glass enters the heating furnace, the lower surface of the glass is heated by natural convection, and the upper surface of the glass forms an air screen due to the cold air. If there is no forced convection, the effect of natural convection heating is very small. The natural convection on the four sides of block flat glass has a significant effect, which generally causes the "hot edge" of the glass, making the edge temperature of the glass too high, thus affecting the optical imaging quality of the glass;

2. Forced convection with heat balance pipe: Generally, there is a heat balance air pipe near the heating element in the heating furnace. The compressed air in the air pipe is heated to become hot air and blown directly on the upper and lower surfaces of the glass. The heat balance gas heats the glass by forced convection on the one hand, and makes the temperature in the heating furnace uniform on the other hand; but when the glass is in a high-temperature softening state, the airflow with a certain speed and pressure will form "grain" on the surface of the softened glass, which is also the disadvantage of this forced convection;

3. Forced convection as the main heating method: Both gas heating furnaces and air cushion heating furnaces use forced convection as one of the main heating methods. With the rapid promotion of the market application of tempered Low-E glass, forced convection heating furnaces using high-temperature fans or compressed air have also been developed. The use of forced convection heating can shorten the glass heating time, improve production efficiency, make the glass temperature more uniform, and improve product quality.

Heat conduction: The upper surface of the glass does not contact the components in the furnace, only the lower surface contacts the ceramic roller. The ceramic roller is made of quartz as the main material and is made by adding auxiliary materials. Its thermal expansion coefficient is almost 0 and its thermal conductivity is also very low. The contact area between the ceramic roller and the glass is very small (theoretically it is line contact), so heat conduction is not the main method in the entire heat transfer process. Less than 10% of the heat absorbed by the glass in the heating furnace comes from heat conduction. However, in the early stage of the cold glass entering the furnace, the lower surface of the cold glass contacts the high-temperature ceramic roller, which will cause the glass to warp and shake. This needs to be noted.

At present, when the radiation tempering furnace in the industry heats the glass, its heat source comes from the electric heating elements on the top and bottom of the furnace, which are usually nickel-chromium resistance wires. There are two ways to install the electric heating elements. One is to be installed in a metal tube to radiate heat in the form of a radiation tube; the other is to be mounted on a heat-resistant ceramic tube, and the resistance wire directly radiates heat into the furnace. The glass is usually placed flat on a transmission roller made of heat-resistant ceramic as the main component, and is sent into the furnace by the rotation of the roller. In order to temper large-sized flat glass, the electric heating elements in the furnace are generally arranged as full as possible on the top and bottom of the furnace. When the glass is sent into the furnace at room temperature, it is subjected to the radiation heat transfer of the electric heating elements and the heat conduction of the transmission roller to the contacted glass. Since the furnace temperature is generally around 700℃, the temperature of the transmission roller is relatively high, and the glass obtains a large amount of heat through heat conduction, making the temperature of the lower surface of the glass higher than the temperature of the upper surface, causing uneven temperature distribution in the thickness direction of the glass plate, and the glass bends and the edges are upturned. At this time, gravity is concentrated in the middle of the glass plate, forming a roller mark. Uneven heating can also cause white spots to appear in the center of the glass, a problem that is more serious when tempering the substrate of laminated glass.

Low-E glass is coated on one side of ordinary glass. In order to avoid damage to the coating layer by the roller during tempering, the coated surface is sent into the tempering furnace with the coating facing up. From the perspective of heat transfer, in order to ensure that the glass is heated evenly, the heat transfer rate from the upper and lower surfaces of the glass to the inside of the glass is required to be consistent during heating. The electric heating element mainly heats the Low-E glass by radiation. Its infrared radiation projected onto the object will produce a significant thermal effect and is the main component of heat rays. The emissivity of Low-E glass is uneven, and the lower surface of the glass has a very high emissivity of about 0.90. After absorbing a large amount of heat, the temperature of the lower surface rises, and the effective thermal conductivity increases, allowing the heat to be further transferred to the inside. The emissivity on the coated side is generally between 0.10 and 0.23. The coating layer reflects a large amount of infrared radiation energy, making it difficult for thermal radiation to be transferred from the coated surface to the inside of the glass.

Currently in the industry, in order to evenly heat the glass surface, the surface of the glass must be completely covered with heating elements. This surface heating method is characterized by the need to apply at least 50% of the heat of the heat source to the surface of the heated object or the layer near the surface. Traditional heating methods have limitations. For example, using chromium-aluminum-cobalt metal wire resistance wire heating, the maximum load of the heater wall can only reach 60kW/㎡ at 1000℃, but the power density radiated by the full black radiator at the same temperature can reach 149kW/㎡. In traditional resistance wire heating, the heaters are arranged extremely densely, and this arrangement will shorten the service life of the heating element.

During the glass heating process, the maximum heating temperature of the traditional electric heating element nickel-chromium alloy is 1150℃, and the maximum heating temperature of iron-chromium alloy is 1400℃. Considering the furnace temperature and cost, most of the electric heating elements in the industry are made of nickel-chromium alloy. According to the corresponding relationship between the heat source temperature and the wavelength of radiation, the wavelength of the outward radiation at the heating temperature of 1150℃ is 2.04 microns. Considering the furnace temperature and the glass tempering temperature, the heating temperature of the resistance wire in the electric heating tempering furnace is lower than 1150℃, usually between 800 and 900℃, and the corresponding heat source radiation wavelength is 2.47 to 2.7 microns. This wavelength is actually relatively narrow, and not all glass absorption wavelengths are between 2.47 and 2.7 microns.

At present, the industry has gradually begun to use an infrared radiator to uniformly heat transparent glass to increase the glass heating speed and shorten the heating time. However, the disadvantage of this method is that it cannot ensure uniform radiation of the entire surface of the glass object, resulting in a projection of the intensity distribution of the infrared radiation source on the glass surface to be heated.

In order to solve the above problems, the glass industry has introduced "forced convection heat exchange technology" in the tempering furnace. Adding forced convection in the upper part of the roller tempering furnace is beneficial to the symmetrical heating of the glass. Moreover, for Low-E glass, the presence of the coating greatly increases the heating time, while adding forced convection can shorten the heating time and reduce the furnace temperature, which is very beneficial to reducing the loss of the film layer and improving production efficiency. It is unnecessary to add forced convection in the lower part. Originally, the roller tempering furnace, due to the inevitable roller heat transfer and natural convection in the lower part, heats the lower part too quickly, and the glass warps up to form white fog in the middle. More importantly, the middle part is heated too quickly. When the center of the glass is heated to the tempering temperature, the lower surface is overheated and too soft, causing pitting or roller marks on the lower surface of the glass, which is a headache. If forced convection is added to the lower part, this contradiction will be more prominent.

However, current glass tempering, especially coated glass and Low-E glass tempering, still has problems such as glass warping and shaking due to the rapid rise in temperature of the lower surface of the glass and the slow rise in temperature of the upper surface of the glass in the early stage of entering the furnace; the extremely dense distribution of heating elements in traditional electric heating tempering furnaces leads to a short lifespan and slow heating speed; and the infrared radiation heating technology currently introduced in tempering furnaces causes uneven heating and high energy consumption.

Summary of the invention

The purpose of the embodiments of the present application is to provide a glass tempering heating furnace.

The present application provides a glass tempering heating furnace, comprising:

The preheating furnace body has a feed inlet, and a main smoke exhaust port is arranged at the feed inlet; along the traveling direction of the glass, the preheating furnace body is divided into multiple sections, and each section is provided with a smoke extraction port and a smoke injection interface; the smoke extraction port is used to extract the smoke from the preheating section; the smoke injection interface is used to send the extracted smoke into the furnace body;

The heating section furnace body is provided with a plurality of infrared burners, and the infrared burners are porous medium burners; the smoke from the heating section furnace body is extracted through the smoke extraction port, and the extracted smoke is sent into the preheating section furnace body through the smoke injection interface.

The smoke exhaust port of the heating section is moved forward to the position of the feed port of the preheating section. On the one hand, the macroscopic flow of smoke from the heating section to the preheating section is constructed, and at the same time, it serves as the source of heat for the preheating section; on the other hand, the smoke exhaust port is separated from the heating section by a certain distance, which reduces the influence of smoke exhaust on the temperature field of the heating section. By setting up the preheating section furnace body, on the one hand, the smoke of the heating section furnace body is reused; on the other hand, the smoke is extracted by the smoke extraction port and sent back by the smoke injection interface, so as to realize the step-by-step heating of the glass in the preheating section furnace body. At the same time, the glass as a cold source continues to enter the preheating section furnace body, and the temperature of the drive roller of the preheating section furnace body will be much lower than that of the drive roller of the heating section furnace body. The heat of the preheating section furnace body of the present application comes from the smoke of the heating section furnace body, so that the deformation (upward) and shaking caused by the large temperature difference between the upper and lower surfaces of the glass when it enters the heating furnace due to the excessively high temperature of the drive roller can be well avoided. Optionally, the heating section furnace body adopts a porous medium combustion technology based on infrared radiation to construct a wide-band infrared heating section, so as to achieve rapid and uniform heating of the glass.

The glass tempering heating furnace of the present application is not only applicable to the tempering heating of ordinary glass, but is especially suitable for the tempering requirements of coated glass and Low-E glass.

In other embodiments of the present application, in the preheating section furnace body, multiple flue gas injection air knives can be arranged on the upper and lower sides of the drive roller along the direction of glass travel, and the multiple flue gas injection air knives on the upper and lower sides and the multiple drive rollers are staggered in the height direction; the smoke injection interface is used to send the extracted smoke into the multiple smoke gas injection air knives.

In other embodiments of the present application, the diameters of the air outlets of the multiple smoke injection air knives can be shrunk.

In other embodiments of the present application, an incrementer may be provided in the preheating furnace body, the incrementer having a channel of a venturi tube structure, and the channel is connected to the air outlets of a plurality of flue gas injection air knives.

In other embodiments of the present application, a plurality of infrared burners are staggeredly arranged on the upper and lower sides of the driving roller along the traveling direction of the glass.

In other embodiments of the present application, the infrared burner of the heating section furnace body may be a combustion component having a porous medium material.

In other embodiments of the present application, the porous medium material may be a SiC material, wherein the emissivity of the SiC material is 0.9.

In other embodiments of the present application, an airflow stirring device may be further provided in the heating section furnace body, and the airflow stirring device and the infrared burner may be spaced apart along the traveling direction of the glass.

In other embodiments of the present application, the glass tempering heating furnace may further include: a soaking section furnace body; the soaking section furnace body is arranged behind the heating section furnace body along the traveling direction of the glass; and a plurality of air ducts are arranged in the soaking section furnace body for generating horizontal parallel airflows on the upper and lower surfaces of the glass.

In other embodiments of the present application, the plurality of air ducts may be four independently controlled air ducts, wherein the four independently controlled air ducts are a first air duct, a second air duct, a third air duct and a fourth air duct.

The furnace body of the soaking section realizes forced convection by setting up air ducts for generating horizontal parallel airflow on the upper and lower surfaces of the glass, and ensures the temperature uniformity of the glass entering the rapid cooling process through the convection heat exchange of the airflow.

In other embodiments of the present application, the air duct may include a centrifugal fan and an air duct body; the centrifugal fan is used to rotate to suck in wind, and to throw out wind so that the wind flows in the air duct body and is blown out from the gaps between the drive rollers, horizontally and parallely passing over the upper and lower surfaces of the glass, completing heat exchange with the glass.

In other embodiments of the present application, the equalizing section furnace body may further include a heater, which is used to heat the air that has completed the heat exchange to a preset temperature; the air heated to the preset temperature is sucked in by the centrifugal fan again, and after being evenly stirred, it is blown out from the air duct to the upper and lower surfaces of the glass.

In other embodiments of the present application, the preheating section furnace body, the heating section furnace body and the soaking section furnace body can be equally divided into an upper furnace body and a lower furnace body; the upper furnace body is arranged above the driving roller, and the lower furnace body is arranged below the driving roller.

In other embodiments of the present application, the preheating section furnace body, the heating section furnace body and the soaking section furnace body may all be provided with a furnace body lifting device, and the furnace body lifting device is connected to the upper furnace body for lifting the upper furnace body.

The present application provides a glass tempering method, wherein the glass tempering method uses a glass tempering heating furnace according to an embodiment of the present application to perform a tempering process on the glass, and the glass tempering method comprises:

The glass runs on the transmission rollers and enters the preheating furnace body, where the product is preheated.

The glass enters the heating section furnace from the preheating section furnace, and the product temperature rises to 600-640°C. After reaching the set temperature, the glass continues to operate at the set temperature;

The glass enters the soaking section furnace from the heating section furnace, and the circulating gas passes over the upper and lower surfaces of the glass to heat the glass and make the temperature uniform.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

FIG1 is a schematic structural diagram of a glass tempering heating furnace provided in an embodiment of the present application;

FIG2 is a schematic structural diagram of a preheating section furnace body of a glass tempering heating furnace provided in an embodiment of the present application from a first perspective;

3 is a schematic structural diagram of a preheating section furnace body of a glass tempering heating furnace provided in an embodiment of the present application from a second perspective;

FIG4 is a schematic structural diagram of a preheating section furnace body of a glass tempering heating furnace provided in an embodiment of the present application from a third perspective;

FIG5 is a schematic diagram of the structure of the flue gas injection interface of the preheating section of the glass tempering heating furnace provided in an embodiment of the present application;

FIG6 is a schematic diagram of the enlarged structure of the flue gas injection interface and the incrementer of the preheating section of the glass tempering heating furnace provided in an embodiment of the present application;

FIG7 is a schematic structural diagram of a heating section furnace body of a glass tempering heating furnace provided in an embodiment of the present application from a first perspective;

FIG8 is a schematic structural diagram of a heating section furnace body of a glass tempering heating furnace provided in an embodiment of the present application from a second perspective;

FIG9 is a schematic structural diagram of a furnace body of a soaking section of a glass tempering heating furnace provided in an embodiment of the present application;

10 is a cross-sectional view of a single air duct of a furnace body of a soaking section of a glass tempering heating furnace provided in an embodiment of the present application in the width direction of the furnace body;

FIG11 is a flow field analysis diagram of the present application;

FIG12 is an infrared transmission curve of a certain type of glass.

Icons: 10-glass tempering heating furnace; 20-glass; 100-preheating furnace body; 101-driving roller; 102-preheating upper furnace body; 103-preheating lower furnace body; 120-main smoke exhaust port; 130-smoke exhaust port; 131-first smoke exhaust port; 132-second smoke exhaust port; 133-third smoke exhaust port; 134-fourth smoke exhaust port; 135-fifth smoke exhaust port; 136-sixth smoke exhaust port; 140-smoke injection interface; 141-first smoke injection interface; 142-second smoke injection interface; 143-third smoke injection interface; 144-fourth smoke injection interface; 150-smoke injection air knife; 151-air knife on the right side of the upper furnace body; 152- Wind knife on the left side of the upper furnace body; 153-air outlet; 160-increaser; 161-channel of the venturi tube structure; 162-contraction section; 163-gap; 164-exit; 200-heating section furnace body; 201-upper furnace body of the heating section; 202-lower furnace body of the heating section; 210-infrared burner; 220-air flow stirring device; 300-heating section furnace body; 310-air duct; 311-centrifugal fan; 312-air duct body; 320-heater; 330-upper furnace body of the heat-saturating section; 340-lower furnace body of the heat-saturating section; 350-first air duct; 360-second air duct; 370-third air duct, 380-fourth air duct; 400-furnace body lifting device.

Detailed ways

In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments.

Therefore, the following detailed description of the embodiments of the present application is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

1 to 11 , an embodiment of the present application provides a glass tempering heating furnace 10 , comprising: a preheating section furnace body 100 , a heating section furnace body 200 , and a soaking section furnace body 300 , which are sequentially arranged along the glass traveling direction.

Optionally, in some embodiments of the present application, the preheating stage furnace body 100 has a feed inlet, and a main smoke exhaust port 120 is arranged near the feed inlet.

In the related art, the main smoke exhaust port is usually set in the heating section, while in the present application, the smoke exhaust port of the heating section is moved forward to the feed port of the preheating section. On the one hand, the smoke is moved from the heating section to the preheating section as a source of heat for the preheating section; on the other hand, the influence of the smoke exhaust on the temperature field of the heating section is reduced.

Optionally, in some embodiments of the present application, the preheating furnace body is divided into multiple sections along the traveling direction of the glass, and each section is provided with a smoke extraction port 130 and a smoke injection interface 140; the smoke extraction port 130 is used to extract smoke from the preheating section. The smoke from the heating furnace body 200 is extracted through the smoke extraction port 130, and the extracted smoke is sent into the preheating furnace body 100 through the smoke injection interface 140.

Currently in the industry, the flue gas generated by the heating section of the glass tempering heating furnace is exhausted by setting a smoke outlet at the inlet of the furnace and connecting an external chimney to the "chimney effect".

The present application introduces the preheating furnace body 100 in front of the heating furnace body 200, sets the total smoke exhaust port 120 of the whole set of equipment at the entrance of the preheating furnace, and sets a smoke exhaust port 130 in each section of the preheating furnace body 100 along the direction of glass travel. The smoke in the furnace can be extracted from each smoke exhaust port 130 by a fan, and then the extracted smoke is sent into the furnace through the smoke injection interface 140 of each section, so as to construct the internal circulation of smoke in the preheating furnace body. In this way, the pressure in the furnace can be kept at the preset index of "micro positive pressure", and then the overall flow direction of the smoke in the furnace can be realized from the heating furnace body 200 to the preheating furnace body 100.

By setting up the preheating furnace body 100, on the one hand, the flue gas of the heating furnace body 200 is reused; on the other hand, the preheating furnace body 100 is divided into multiple sections, and the flue gas is extracted by the smoke outlet 130 and sent back by the flue gas injection interface 140, so as to realize the step-by-step heating of the glass in the preheating furnace body 100. At the same time, the heat of the preheating furnace body 100 comes from the flue gas of the heating furnace body 200. Considering the continuous entry of glass as a cold source, the temperature of the driving roller 101 of the preheating furnace body 100 will be much lower than the temperature of the driving roller 101 of the heating furnace body 200. In this way, the deformation (upward) and shaking caused by the large temperature difference between the upper and lower surfaces of the glass at the initial stage of entering the heating furnace due to the excessively high temperature of the driving roller 101 can be well avoided.

Conventional glass tempering heating furnaces in the related art need to solve the problem of warping and shaking of the glass caused by uneven heating of the glass in the initial stage in the heating section. The glass tempering heating furnace 10 of the present application is completely different from the conventional glass tempering heating furnace in the related art. It creatively sets up a separate preheating section furnace body 100, uses the flue gas in the heating section as a heat source, sets up a separate preheating section, reduces the temperature of the ceramic roller in the preheating section, and preheats the glass in the form of forced convection, thereby solving the problem of warping and shaking of the glass caused by uneven heating of the glass in the initial stage.

Optionally, in some embodiments of the present application, the preheating furnace body 100 is divided into three sections along the traveling direction of the glass. The preheating furnace body 100 is divided into an upper preheating furnace body 102 and a lower preheating furnace body 103. The upper preheating furnace body 102 is arranged above the driving roller 101, and the lower preheating furnace body 103 is arranged below the driving roller 101.

2-3, the preheating furnace body 100 is divided into "upper 1#" and "lower 1#" sections, "upper 2#" and "lower 2#" sections, "upper 3#" and "lower 3#" sections, a total of 6 sections. In each of the 6 sections, a smoke extraction port 130 is provided on the furnace body, and the smoke in the furnace is extracted by a fan, and then the extracted smoke is sent into the furnace through the smoke injection interface 140 of each section, thereby constructing the internal circulation of the smoke in the preheating furnace body 100.

Exemplarily, referring to Figures 2 and 3, in the preheating section furnace body 100, the upper 1# section is provided with a first smoking port 131, the lower 1# section is provided with a second smoking port 132, the upper 2# section is provided with a third smoking port 133, the lower 2# section is provided with a fourth smoking port 134, the upper 3# section is provided with a fifth smoking port 135, and the lower 3# section is provided with a sixth smoking port 136.

Optionally, taking the upper 1# section as an example, the first smoke extraction port 131 of the section is connected to the exhaust port of the smoke extraction fan, and the smoke in the furnace is extracted by the fan, and is divided into two through the pipeline, and is respectively sent to the first smoke injection interface 141 and the second smoke injection interface 142 of the upper 1# section. Similarly, the second smoke extraction port 132 set in the lower 1# section is connected to the exhaust port of the smoke extraction fan, and the smoke in the furnace is extracted by the fan, and is divided into two through the pipeline, and is respectively sent to the third smoke injection interface 143 and the fourth smoke injection interface 144 of the lower 1# section.

Optionally, in some embodiments of the present application, in the preheating section furnace body 100, along the direction of glass travel, a plurality of flue gas injection air knives 150 are provided on the upper and lower sides of the drive roller 101, and the multiple flue gas injection air knives 150 on the upper and lower sides and the multiple drive rollers 101 are staggered in the height direction; the flue gas injection interface 140 is used to deliver the extracted flue gas into the multiple flue gas injection air knives 150.

2-4 , in the illustrated embodiment, multiple flue gas injection air knives 150 are provided in the six sections of the preheating furnace body 100, namely, the "upper 1#" section and the "lower 1#" section, the "upper 2#" section and the "lower 2#" section, and the "upper 3#" section and the "lower 3#" section.

Optionally, in some embodiments of the present application, the diameters of the air outlets 153 of the plurality of smoke injection air knives 150 are shrunk.

By setting a plurality of flue gas jet air knives 150 with shrinking apertures of the air outlets 153 , this gradually decreasing structure can enable the ejected cooling medium (wind) to form a high flow rate and a jet state.

Optionally, in some embodiments of the present application, an incrementer 160 is disposed in the preheating furnace body 100 , and the incrementer 160 has a channel 161 of a venturi tube structure, and the channel is connected to the air outlets 153 of the plurality of flue gas injection air knives 150 .

6 and 11, by providing the increaser 160 with a channel 161 of a venturi tube structure, a venturi effect can be generated, forming an "incremental" effect, and amplifying the amount of air blown to the glass. The structure of the increaser 160 provided in the present application has been verified by flow field simulation analysis and actual experiments, and the application of the increaser 160 greatly enhances the heating effect.

In the related art, the smoke injection structure usually adopts the traditional "circular hole staggered arrangement type" and "slit type" smoke injection structure. The present application creatively develops a structure with an "incremental" effect to increase the amount of injected smoke and optionally improve the heating efficiency.

For example, referring to FIG. 5-FIG. 6, in the illustrated embodiment, the "incremental" structure of flue gas injection in the preheating section furnace body 100 is shown in FIG. 5 and FIG. 6. In the empty furnace heating stage, the drive roller 101 in the furnace is cold. In order to avoid the high-temperature flue gas from being directly sprayed onto the surface of the drive roller 101, the flue gas injection air knife 150 will not blow directly to the drive roller 101 but will be staggered and blow to the gap between the drive rollers 101. As shown in FIG. 5 and FIG. 6, the internal structure of the preheating section furnace body 100 mainly consists of: a drive roller 101, a right wind knife 151 of the upper furnace body, a left wind knife 152 of the upper furnace body, and an incrementer 160. The glass runs from left to right under the rotation of the drive roller 101. The fan extracts the flue gas in each section of the furnace, and sends the preheated flue gas into the flue gas injection air knife 150 through the flue gas injection interface 140 outside the furnace. The flue gas injection air knife 150, which is specially designed for structure, contracts at the outlet, and forms the cooling medium into a high-flow, injection state. An incrementer 160 is installed at a certain distance from the outlet of each smoke jet air knife 150. The incrementer 160 is specially designed to form an "incremental" effect, amplifying the air volume blowing toward the glass. After flow field simulation analysis and actual experimental verification, the application of the incrementer 160 greatly enhances the heating effect.

Optionally, referring to FIG. 6 , the flue gas ejected from the flue gas jet air knife 150 increases in velocity when passing through the contraction section 162 of the incrementer 160, and forms a low-pressure zone. Under the action of the low-pressure zone, the flue gas existing in the preheating furnace body 100 is sucked into the incrementer 160 from the gap 163 between the flue gas jet air knife 150 and the incrementer 160. The two streams of flue gas converge at the outlet 164 of the incrementer 160 and are ejected toward the heating surface of the glass 20. Thus, under the same flue gas fan power, a greater amount of flue gas can be ejected on the heating surface of the glass.

Optionally, in some embodiments of the present application, the heating section furnace body 200 is disposed behind the preheating section furnace body 100 along the traveling direction of the glass.

Optionally, in some embodiments of the present application, referring to Figures 7 and 8, the heating section furnace body 200 is divided into a heating section upper furnace body 201 and a heating section lower furnace body 202. The heating section upper furnace body 201 is arranged above the driving roller 101, and the heating section lower furnace body 202 is arranged below the driving roller 101.

Optionally, in some embodiments of the present application, the heating section furnace body 200 is provided with a plurality of infrared burners 210 , and the infrared burners 210 are porous medium burners.

The heating section furnace body 200 of the present application adopts porous medium combustion technology based on infrared radiation, and there are three heat exchange modes: convection, heat conduction and radiation, so that the temperature of the combustion area tends to be uniform and maintains a relatively stable temperature gradient. While the combustion is stable, it also has a high volumetric thermal intensity. Compared with free combustion, porous medium combustion has the advantages of high combustion rate, good combustion stability, large load adjustment range, large volumetric thermal intensity, small burner size, good gas adaptability, low pollutant emissions in flue gas, wider combustion limit, and combustible gas with very low calorific value.

In the art, conventional heating furnaces are traditional gas fuel combustion, mainly characterized by free flame combustion. This type of combustion requires a large space, the temperature gradient around the flame is large, and local high temperature is easily generated. When the temperature is higher than 1500°C, _NOx (nitrogen oxides) generation becomes obvious. Due to the high toxicity of _NOx (nitrogen oxides), reducing its emissions is also very important.

Compared with the conventional free flame combustion of conventional heating furnaces, the heating section furnace body 200 of the present application uses a porous medium combustion furnace to greatly improve the combustion effect. In the combustion process, the porous medium plays a key role. The porous medium material has the following characteristics: excellent heat transfer characteristics, forced gas flow in and out, separate and merge, enhanced convection, uniform temperature distribution, and can maintain a low temperature level, which can reduce pollutant emissions; the volume density is very small, that is, the thermal inertia is very small, it can heat up quickly at startup, and can quickly adapt to load changes. It can work in the temperature range of 800-1200℃ and other characteristics.

Optionally, in some embodiments of the present application, the infrared burner 210 of the heating section furnace body 200 described above uses a porous medium material as the main combustion component, and the gas burns in the porous medium material. Optionally, the porous medium material of the present application selects SiC, and the emissivity of SiC material is about 0.9, which is much higher than the emissivity of general metal alloy heating materials, and the radiation heating effect is better. The infrared burner 210 of the heating section furnace body 200 of the present application further improves the heating effect by using SiC as the porous medium material.

Optionally, the heating section furnace body 200 of the present application adopts an infrared burner with "porous medium combustion" technology as the core.

Optionally, in some embodiments of the present application, in the heating section furnace body 200 , a plurality of infrared burners 210 are staggeredly arranged on the upper and lower sides of the driving roller 101 along the traveling direction of the glass.

7 , in the illustrated embodiment, in the heating section furnace body 200 , each infrared burner 210 in the upper furnace body and each infrared burner 210 in the lower furnace body are staggered with each other in the traveling direction of the glass.

By staggering the plurality of infrared burners 210 on the upper and lower sides of the driving roller 101 in the heating section furnace body 200 along the glass traveling direction, the heating uniformity can be improved.

Optionally, in some embodiments of the present application, an airflow stirring device 220 is further provided in the heating section furnace body 200 , and the airflow stirring device 220 and the infrared burner 210 are spaced apart along the traveling direction of the glass.

The disadvantage of infrared radiation is that it cannot ensure uniform radiation of the entire surface of the glass object, resulting in a projection of the intensity distribution of the infrared radiation source on the glass surface to be heated. Therefore, the present application sets an airflow stirring device 220 in the heating section furnace body 200 to cooperate with the infrared burner 210. The airflow stirring device 220 is arranged at intervals from the infrared burner 210. The airflow stirring device 220 can stir the flue gas in the furnace, on the one hand, to avoid the local concentration of high-temperature flue gas in the furnace, resulting in uneven furnace temperature; on the other hand, the stirred flue gas flows at a certain speed on the glass surface, increasing the convective heat transfer.

For example, referring to FIG. 7 and FIG. 8 , in the illustrated embodiment, the main structure of the heating section furnace body 200 is shown in FIG. 7 and FIG. 8 , and the infrared burners 210 are arranged staggered in the direction of glass travel to avoid uneven temperature field caused by heat concentration. From the perspective of temperature control, the heating section furnace body 200 is divided into 4 zones, each zone is equipped with an air flow stirring device 220. From the top view of FIG. 8 , in the width direction of the furnace, the infrared burners 210 are arranged on both sides.

Optionally, in some embodiments of the present application, a plurality of air ducts 310 are provided in the soaking section furnace body 300 to generate horizontal parallel airflows on the upper and lower surfaces of the glass.

Glass "tempering" includes the process of "heating" and "cooling". If the uniformity of the glass surface temperature is not well guaranteed before the glass enters the rapid cooling process, it will cause serious quality problems in the rapid cooling process.

The disadvantage of infrared radiation is that it cannot ensure uniform radiation of the entire surface of the glass object, resulting in a projection of the intensity distribution of the infrared radiation source on the glass surface to be heated. Although the heating section furnace body 200 is provided with an air flow stirring device 220 to alleviate the uneven temperature of the glass surface during the heating stage, it is still a certain distance away from the high standard uniformity requirement.

As mentioned in the background technology, the current practice of peers in the industry is to equip the heating section with forced convection. In this practice, when the glass is in a high-temperature softening state, the airflow with a certain speed and pressure will form "textures" on the surface of the softened glass. This application solves this problem by setting up a soaking section and constructing a horizontal parallel airflow in the soaking section.

Alternatively, in addition to the above-mentioned disadvantages, forced convection has a relatively serious impact on the "porous medium burner" due to the high-speed airflow in the furnace for gas direct-fired heating.

The thermal conductivity of glass is very low. If you want to achieve temperature uniformity of glass within a specified time while meeting production capacity, you must find a way to increase the convective heat transfer efficiency/capacity. For airflow uniform heating technology, if you want to ensure the temperature uniformity of the product, you must meet one of the following two conditions:

(1) The airflow is sufficiently turbulent;

(2) Adequate level of airflow.

A sufficiently turbulent airflow requires a powerful fan to ensure it, and this airflow is not conducive to the stability of thin glass on the drive roller 101. In addition, the impurities in the insulation material and the furnace will be spread all over the furnace and the glass surface under the influence of the turbulent airflow, resulting in uncontrollable problems in the surface quality of the glass. In the industrial furnace industry, it is a very good practice to blow a fully uniform airflow horizontally and parallel to the workpiece surface, especially the workpiece surface with a very low thermal conductivity, to ensure the temperature uniformity of the workpiece heating process.

In this application, the forced convection of the "horizontal parallel airflow" is introduced into the soaking section furnace body 300 after the heating section furnace body 200, which is equivalent to the final heating + temperature adjustment process, and the power required is much less than the power of the heating section, which requires the power output of the heater to respond quickly and be continuously adjustable. In this application, the heat source of the soaking section furnace body 300 is an electric heating tube integrated box, and the electric heating integrated box is integrally inserted into the air duct.

Optionally, in some embodiments of the present application, referring to FIG. 9 and FIG. 10 , the soaking section furnace body 300 is divided into a plurality of sections in total. By way of example, it is divided into 4 sections in the figure, and an independent air duct 310 is provided in each section.

Optionally, in some embodiments of the present application, the above-mentioned air duct 310 includes a centrifugal fan 311 and an air duct body 312; the centrifugal fan 311 is used to rotate to inhale wind, and throw out wind so that the wind flows in the air duct body 312, and blows out from the gap between the drive rollers 101, horizontally and parallelly passing over the upper and lower surfaces of the glass, completing heat exchange with the glass.

Optionally, in some embodiments of the present application, the equalizing section furnace body 300 also includes a heater 320, which is used to heat the wind that has completed the heat exchange to a preset temperature; the wind heated to the preset temperature is sucked in by the centrifugal fan 311 again, and after being evenly stirred, it is blown out from the air duct body 312 to the upper and lower surfaces of the glass.

In the illustrated embodiment, referring to FIG9 and FIG10, the soaking section furnace body 300 has a total of 4 independently controlled air ducts, namely the first soaking section air duct 350, the second soaking section air duct 360, the third soaking section air duct 370, and the fourth soaking section air duct 380. The cross section of a single air duct in the width direction of the furnace body is shown in FIG10. The centrifugal fan 311 rotates at a high speed, and the wind is sucked in from the bottom opening of the impeller of the centrifugal fan 311 and thrown out from the tangential direction. The wind flows in the air duct body 312, blows out from the gap between the adjacent transmission rollers 101, and passes horizontally and parallelly over the upper and lower surfaces of the glass. The wind blown out of each section of the air duct can cover the glass surface passing through the section and complete heat exchange with the glass. The temperature of the wind that completes the heat exchange is reduced, and after being heated by the heater 320 in the soaking section furnace body 300, it reaches the specified temperature again. In fact, the temperature distribution of the wind heated by the heater 320 in the soaking section furnace body 300 is uneven, and this uneven wind cannot be blown directly to the glass. In the present application, the impeller of the centrifugal fan 311 also has a stirring function, which fully stirs and disperses the uneven wind after being heated by the heater 320 in the heat-saturating furnace body 300, so as to achieve temperature uniformity. The uniform wind is sent into the air duct body 312 again to complete the heating and temperature control of the glass.

Optionally, in some embodiments of the present application, the soaking section furnace body 300 is divided into an upper soaking section furnace body 330 and a lower soaking section furnace body 340; the upper soaking section furnace body 330 is arranged above the driving roller 101, and the lower soaking section furnace body 340 is arranged below the driving roller 101. The centrifugal fan 311 and the air duct body 312 are respectively arranged in the upper furnace body and the lower furnace body of each section of the soaking section furnace body 300.

By setting the preheating section furnace body 100, the heating section furnace body 200 and the soaking section furnace body 300 to be two-section, it is convenient to install or remove the drive roller 101 and maintain the equipment. Optionally, the drive roller 101 can be a ceramic roller commonly used in the art.

Optionally, in some embodiments of the present application, the above-mentioned preheating section furnace body 100, heating section furnace body 200 and soaking section furnace body 300 are all provided with a furnace body lifting device 400, and the furnace body lifting device 400 is connected to the upper furnace body for lifting the upper furnace body.

Some embodiments of the present application provide a glass tempering method, which uses the glass tempering heating furnace provided by any of the aforementioned embodiments to temper the glass.

For example, in some embodiments of the present application, using the glass tempering heating furnace provided in any of the aforementioned embodiments to temper glass includes the following steps:

Step S1, manually (or by automated device) laying out the glass in a single layer on the side distribution table and placing the products;

Step S2, the glass runs on the driving roller 101 and enters the preheating furnace body 100, where the product is preheated (the temperature is controlled within a certain range);

Step S3, the glass starts to enter the heating section furnace body 200, the product temperature rises to 600-640°C, and after reaching the set temperature, the glass continues to operate at the set temperature;

Step S4, the glass enters the equalizing furnace body 300 from the heating furnace body 200, and the circulating gas passes over the upper and lower surfaces of the glass to heat the glass and make the temperature uniform. The gas that has completed the heat exchange with the relatively low temperature and non-uniform temperature glass is circulated to the heater, and the temperature is raised and supplemented by the heating in the heater. After the strong stirring of the centrifugal fan impeller, the temperature of the non-homogenized gas is uniformized. After the action of the centrifugal fan and the air duct, it is blown to the upper and lower surfaces of the glass again.

After the temperature is raised and the temperature is uniform, the glass can enter the next process.

The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Industrial Applicability

The present application relates to the field of glass tempering, and to a glass tempering heating furnace. The heating furnace includes a preheating section furnace body, a heating section furnace body, and a soaking section furnace body. Along the traveling direction of the glass, the preheating section furnace body is divided into multiple sections, each section is provided with a smoke extraction port and a smoke injection interface; the smoke extraction port is used to extract the smoke from the preheating section; the smoke injection interface is used to send the extracted smoke into the furnace body; the heating section furnace body is provided with multiple infrared burners, and the infrared burners are porous medium burners; the smoke from the heating section furnace body is extracted through the smoke extraction port of the preheating section, and the extracted smoke is sent into the preheating section furnace body through the smoke injection interface; the soaking section furnace body is provided with multiple air ducts for generating horizontal parallel airflows on the upper and lower surfaces of the glass. The heating furnace of the present application can heat the glass quickly and evenly. It is not only suitable for the tempering heating of ordinary glass, but is especially suitable for the tempering requirements of coated glass and Low-E glass.

In addition, it is understood that the glass tempering heating furnace of the present application is reproducible and can be used in a variety of industrial applications. For example, the glass tempering heating furnace of the present application can be used in the field of glass tempering.

Claims

A glass tempering heating furnace, characterized by comprising:

The preheating furnace body has a feed inlet, and a main smoke exhaust port is arranged at the feed inlet; along the traveling direction of the glass, the preheating furnace body is divided into multiple sections, and each section is provided with a smoke exhaust port and a smoke injection interface;

The heating section furnace body is provided with a plurality of infrared burners, and the infrared burners are porous medium burners; the smoke of the heating section furnace body is extracted through the smoke extraction port, and the extracted smoke is sent into the preheating section furnace body through the smoke injection interface.
The glass tempering heating furnace according to claim 1 is characterized in that:

In the preheating section furnace body, along the direction of glass travel, multiple flue gas injection air knives are arranged on the upper and lower sides of the driving roller, and the multiple flue gas injection air knives on the upper and lower sides and the multiple driving rollers are staggered in the height direction; the flue gas injection interface is used to send the extracted flue gas into the multiple flue gas injection air knives.
The glass tempering heating furnace according to claim 2 is characterized in that:

The diameters of the air outlets of the multiple smoke jet air knives are shrunk.
The glass tempering heating furnace according to claim 3 is characterized in that:

An incrementer is arranged in the preheating section furnace body, and the incrementer has a channel with a venturi tube structure, and the channel is connected to the air outlets of the multiple flue gas injection air knives.
The glass tempering heating furnace according to any one of claims 1 to 4, characterized in that:

Along the traveling direction of the glass, a plurality of infrared burners are staggeredly arranged on the upper and lower sides of the driving roller.
The glass tempering heating furnace according to any one of claims 1 to 5, characterized in that:

The infrared burner of the heating section furnace body is a combustion component having a porous medium material.
The glass tempering heating furnace according to claim 6 is characterized in that:

The porous medium material is SiC material, wherein the emissivity of the SiC material is 0.9.
The glass tempering heating furnace according to any one of claims 5 to 7, characterized in that:

An airflow stirring device is also provided in the heating section furnace body, and the airflow stirring device is spaced apart from the infrared burner along the glass traveling direction.
The glass tempering heating furnace according to any one of claims 1 to 8, characterized in that the glass tempering heating furnace further comprises: a soaking section furnace body; along the traveling direction of the glass, the soaking section furnace body is arranged behind the heating section furnace body;

A plurality of air ducts are arranged in the soaking section furnace body, which are used to generate horizontal parallel airflows on the upper and lower surfaces of the glass.
The glass tempering heating furnace according to claim 9 is characterized in that the multiple air ducts are four independently controlled air ducts, wherein the four independently controlled air ducts are a first air duct, a second air duct, a third air duct and a fourth air duct.
The glass tempering heating furnace according to claim 9 or 10 is characterized in that:

The air duct includes a centrifugal fan and an air duct body; the centrifugal fan is used to rotate to inhale wind, and to throw out the wind so that the wind flows in the air duct body and is blown out from the gaps between the driving rollers, horizontally and parallelly passing over the upper and lower surfaces of the glass, completing heat exchange with the glass.
The glass tempering heating furnace according to claim 11, characterized in that:

The equalizing section furnace body also includes a heater, which is used to heat the wind that has completed the heat exchange to a preset temperature; the wind heated to the preset temperature is sucked in by the centrifugal fan again, and after being evenly stirred, it is blown out from the air duct body to the upper and lower surfaces of the glass.
The glass tempering heating furnace according to any one of claims 9 to 12, characterized in that:

The preheating section furnace body, the heating section furnace body and the soaking section furnace body are all divided into an upper furnace body and a lower furnace body; the upper furnace body is arranged above the driving roller, and the lower furnace body is arranged below the driving roller.
The glass tempering heating furnace according to claim 13 is characterized in that the preheating section furnace body, the heating section furnace body and the soaking section furnace body are all provided with a furnace body lifting device, and the furnace body lifting device is connected to the upper furnace body for lifting the upper furnace body.
A glass tempering method, wherein the glass tempering method uses the glass tempering heating furnace according to any one of claims 1 to 14 to perform a tempering process on the glass, and the glass tempering method comprises:

The glass runs on the transmission rollers and enters the preheating furnace body, where the product is preheated.

The glass enters the heating section furnace from the preheating section furnace, and the product temperature rises to 600-640°C. After reaching the set temperature, the glass continues to operate at the set temperature;

The glass enters the soaking section furnace from the heating section furnace, and the circulating gas passes over the upper and lower surfaces of the glass to heat the glass and make the temperature uniform.