Method and apparatus for laminating glass sheets

Abstract

The invention relates to a method for laminating glass sheets, wherein the sandwich structure sheet moving in a heating furnace on a roller is heated by double-sided hot air jets performed by several successive air blowing port sections; to prevent the formation of air bubbles in the finished laminated glass, when the rear edge of the sandwich structure sheet approaches the air blowing port section, the heating of the rear end of the sandwich structure sheet is prevented by switching off the hot air jet of at least one air blowing port section. The invention also relates to an apparatus for laminating glass sheets, comprising a heating furnace, a pair of press rollers, and a device for establishing position data on the sandwich structure sheet, the heating furnace is provided with a roller track, an air blower, heating resistors and air distribution ducts, above and below the roller track there are several successive air blowing boxes, at least one air blowing box is provided with a closing device, by means of which the air jet of the air blowing box towards the sandwich structure sheet can be reduced or prevented when the rear edge of the sandwich structure sheet approaches the air blowing box.

Description

Technical Field

[0001] This invention relates to methods and apparatus for laminating glass sheets. Background Technology

[0002] Laminated glass is used to strengthen glass, thereby improving its safety or providing different coatings or colors. In the lamination process, a plastic film is placed between two glass sheets. The plastic film is, for example, polyvinyl butyral (PVB), ethyl vinyl acetate (EVA), or SentryGlass. TM The most common plastic film thicknesses are 0.38 mm, 0.76 mm, and 1.52 mm. The assembly is heated, causing the plastic film to soften and adhere firmly to the glass sheet via chemical bonds. The plastic film is heated to the target temperature in a laminating furnace, and the temperature measured immediately after furnace treatment on the outer surface of the sandwich structure sheet is 60°C–80°C, depending on the thickness and composition of the sandwich structure sheet and the exact location of the measuring device. At the target temperature, the sandwich structure sheet passes between a pair of pressure rollers, which force air out of its material interface. The laminating furnace with its pressure rollers is also called an exhaust conveyor, and the purpose of using the exhaust conveyor is to remove air from between the material layers and bond the layers together to form a tight sandwich structure sheet. After laminating furnace treatment, air should not be allowed to be absorbed back between the material layers. Successful lamination is typically ensured by an autoclaving process after laminating furnace treatment, which aims to dissolve any remaining air uniformly within the plastic layers.

[0003] The pressure rollers remove air from the moving laminated sheet by compressing it, causing the air at the material interfaces within the laminate to become highly overcompressed and attempt to escape. The air attempts to escape in the opposite direction to the movement of the laminated sheet, which is guided by the compression and movement of the pressure rollers. Therefore, the air to be removed accumulates at the internal interfaces of the laminated sheet, gradually increasing at its rear edge. The ability of the rear edge of the laminated sheet to expel air from the interfaces is particularly important, although some air also escapes through the side edges. A common quality problem in the production of laminated glass is the formation of visible bubbles in the laminated sheet. Visible bubbles can be found immediately after lamination furnace processing or only after autoclaving. The cause of bubble formation is the unsuccessful expulsion of air during the lamination furnace processing described above. To date, the most common location for bubble formation is the rear edge region of the laminated sheet. When using tempered glass, this problem is more common in wide laminated sheets than in narrow laminated sheets, which have thin plastic layers rather than thick plastic layers and exhibit SentryGlass properties when two plastic layers are stacked one on top of the other. TMPlastic, not PVB, is used. For example, when the desired total thickness of the plastic is 1.52 mm and only the most common 0.76 mm thick plastic is available in stock, two layers of plastic are typically used, stacked one on top of the other. Therefore, to obtain a thick laminate layer, more than one plastic film must usually be added between the glass sheets to achieve the desired layer thickness. This can easily lead to the films adhering prematurely at the rear end of the sandwich structure sheet in the laminating furnace, further resulting in air bubbles forming between the film layers. The larger and longer the glass sheet to be laminated, the greater the bubble problem. The longer the sheet, the greater the distance the air must be expelled. The width of the glass being laminated is also a relevant factor, as air is also partially expelled through the sides of the sandwich structure sheet, not just the rear. Overheating the sandwich structure sheet during the lamination stage also leads to the same problem as bubble formation, because in this case, the films melt prematurely and adhere to each other or to the glass, and the remaining air between the layers cannot be expelled by compression with pressure rollers. The surface of the tempered glass sheet also presents additional challenges to lamination. The surface of tempered glass sheets is not completely smooth, but slightly wavy, which makes it easier for air bubbles to form in laminated glass. Cavities are more likely to remain between the wavy surface and the film, and it is not easy for air to be blown out.

[0004] Various attempts have been made to solve this problem.

[0005] In publication US8097107B2, an attempt was made to address this problem by heating the sandwich panel sheet so that the temperature at its front end is higher than that at its rear end to avoid premature sealing of the edges, which would impede the escape of air and moisture if the sandwich panel sheet were heated along its entire length and width. This heating variation along the longitudinal direction of the sandwich panel sheet is achieved by altering the on-time and output of a longitudinal radiant heating element that moves transversely to its direction, thereby heating the front end to a higher temperature than the rear end.

[0006] Publication EP2431172B1 discloses a method for manufacturing composite safety glass. In this method, a heater box module for heating the laminated sheet is used. The heater box module includes an upper heater box from which heat is discharged via an infrared emitter, and hot air is discharged toward the laminated glass via an upper circulating air system.

[0007] Publication FI100009B describes a method and apparatus for laminating glass sheets, wherein the laminated structure to be laminated is preheated to 30°C-45°C by radiant heat, and then subjected to a first pressing between a pair of rollers. Subsequently, the laminated structure is heated to a temperature of 60°C-85°C by double-sided hot air jetting, and then pressed between a second pair of pressure rollers.

[0008] Publication FI118003B describes a method and apparatus for laminating glass sheets, wherein the sandwich structure to be laminated is preheated with radiant heat, and then the sandwich structure is heated by a bilateral hot air shock wave that occurs simultaneously with the radiant heating.

[0009] However, none of the aforementioned solutions satisfactorily address the problem of preventing bubble formation. Summary of the Invention

[0010] The object of the present invention is a method and apparatus for laminating glass sheets, by which the occurrence of air bubbles can be reduced and thus the quality of the laminated glass can be improved.

[0011] The object of the present invention is achieved by a method for laminating glass sheets, in which at least one plastic film is disposed between glass sheets, and the resulting sandwich structure sheet is conveyed along a roller track to a heating furnace, wherein the sandwich structure sheet moving in the heating furnace is heated by double-sided hot air jetting performed by a plurality of consecutive air-blowing orifice sections, wherein the air jets exiting from the air-blowing orifices impact the sandwich structure sheet, and the heated sandwich structure sheet is conveyed between a pair of pressure rollers. In the heating furnace, when the rear edge of the sandwich structure sheet approaches the air-blowing orifice section, the hot air jetting of at least one air-blowing orifice section is cut off, reduced, or prevented from impacting the sandwich structure sheet.

[0012] Another object of the present invention is an apparatus for laminating glass sheets with a plastic film to form a sandwich structure sheet. The apparatus includes a heating furnace, a pair of pressure rollers, and means for establishing position data on the sandwich structure sheet. The heating furnace is provided with a roller track, at least one air blower, a heating resistor, and an air distribution duct. A plurality of consecutive air blowers are provided above and below the roller track. At least one air blower is provided with a sealing device, which reduces or prevents air jets from the air blower toward the sandwich structure sheet when the rear edge of the sandwich structure sheet approaches the air blower.

[0013] Preferred embodiments of the invention are disclosed in the dependent claims. Attached Figure Description

[0014] The invention will now be described in more detail with reference to the accompanying drawings, in which:

[0015] Figure 1 A cross-section of the device according to the invention, viewed from the side, is shown;

[0016] Figure 2 A cross-section of the device according to the invention, viewed from the end, is shown;

[0017] Figure 3 A cover plate of an air-blowing box according to one embodiment of the present invention is shown;

[0018] Figure 4 A baffle scheme for an air jet according to an embodiment of the present invention is shown; and

[0019] Figure 5 The closing of the air inlet of an air box with a perforated plate according to one embodiment of the present invention is shown. Detailed Implementation

[0020] Figure 1 A cross-section of the device according to the invention, viewed from its side, i.e., from direction z, is shown. The laminating furnace includes a heating device that also includes a convection blowing device. The convection blowing device includes a heating resistor, a blower, an air distribution duct, and a blowing box 2. The wall of the blowing box 2 facing the sandwich structure sheet G includes blowing orifices. Blowing boxes 2 are located above and below the sandwich structure sheet. The blowing boxes form several (at least two) consecutive blowing orifice sections in the furnace along the direction of movement of the sandwich structure sheet, wherein air jets exiting from the blowing orifices impact the sandwich structure sheet. Figure 1 In this furnace, continuous air-blowing orifice sections are formed by continuous air-blowing boxes 2. Separate continuous air-blowing orifice sections can also be formed in the furnace in different ways, for example by means of partition walls in the direction of movement of the sandwich structure sheet within a longer air-blowing box. The laminating furnace includes a roller track consisting of several rollers 3 that convey the sandwich structure sheet through the furnace at a traveling speed W during the heating process. The roller gap, i.e., the distance between the centers of the roller axes, is typically 100mm-300mm in the roller track. The air-blowing box is a rounded rectangle, and its length, with air-blowing orifices, covers the entire loading width of the furnace. The loading width is typically between 1m and 3.5m. The cross-section of the air-blowing box is, for example, circular or square, such as... Figure 1 As shown. The measured value of the blow molding box in the direction of movement (direction x) of the sandwich structure sheet is L2, which is preferably 50mm-150mm. The distance L1 between the blow molding boxes is preferably 50mm-200mm. Preferably, there is one blow molding box 2 above and below one roller gap. Figure 1 , Figure 2 and Figure 4 In the diagram, an arrow pointing outward from the air box 2 depicts the air jet exiting from the air outlet. The direction of the air jet is preferably perpendicular to the surface normal of the sandwich structure sheet, or at most at a 20-degree angle to the perpendicular line to the surface normal of the sandwich structure sheet.

[0021] The air blowing box, the multiple rows of air blowing orifices within the air blowing box, or at least a single section of air blowing orifices formed by the air blowing box, is preferably substantially parallel to the roller, i.e., substantially transverse to the direction of movement of the sandwich structure sheet. In the above context, "substantially" means a maximum angular difference of 15 degrees relative to the direction of the roller. The diameter of the air blowing orifice is 4mm-20mm, preferably 5mm-15mm. The shape of the air blowing orifice may also be non-circular, for example, a rounded rectangular gap. The air blowing distance from the air blowing orifice to the surface of the sandwich structure sheet is 30mm-200mm, preferably 50mm-150mm.

[0022] The heating resistor is omitted in the figure. The heating resistor is preferably a resistor package installed in an air distribution duct on the intake side of the air blower, through which the air drawn in by the air blower flows. The heating resistor can also be a separate, rounded rectangular resistor tube that radiates directly toward the upper and lower surfaces of the sandwich structure sheet. The heating resistor can also be other types of air heating devices.

[0023] The device according to the invention also includes a positioning device. A computer determines the position of the rear edge of the sandwich structure relative to the air box based on information provided by the positioning device, so that the jets can be cut off or reduced as planned. The positioning device may be, for example, a phototube, a servo motor of the roller track, or a pulse sensor connected to an actuator of the roller track.

[0024] Figure 2 A cross-section of a laminating furnace according to an embodiment of the invention, viewed from the end of the furnace, is shown. Rollers are not shown because the cross-section is taken at the blowing box. Air discharged from the blowing box 2 heats the sandwich structure sheet G on both surfaces as it travels through the furnace. An air blower 7 draws air from the furnace and blows the drawn air into the blowing box 2 through an air distribution duct 6 and through blowing orifices, where the air is discharged in a jet toward the sandwich structure sheet G.

[0025] The furnace temperature is preferably controlled within the range of 150°C to 250°C, measured from an air distribution duct equipped with thermocouples. A jet of warm air exiting from the air outlet impacts the surface of the sandwich structure sheet, conducting heat deeper into the sandwich structure from the sheet. Typically, the purpose of heating is to raise the plastic film in the sandwich structure to a bonding temperature of 55°C to 75°C. The heated sandwich structure sheet exits the furnace and passes almost immediately through a pair of pressure rollers 4 behind it. The pressure rollers force air out of the sandwich structure sheet from the interlayer interfaces.

[0026] In the heating furnace according to the invention, when the rear edge of the sandwich structure sheet approaches the impact line of the air jet from the air jet of the air jet row, the hot air jet from at least one air jet row is cut off or reduced, or the impact of the hot air jet with the sandwich structure sheet is prevented. At the moment of cutting off or reducing the hot air jet, the distance between the air jet box, the air jet row, or the air jet row and the impact point on the glass surface (this distance is parallel to the surface of the sandwich structure) is... Figure 1 Xi in the process. Continue cutting or reducing the spraying along the remaining length of the sandwich structure until the rear edge of the glass. This reduces heating in the rear edge region of the sandwich structure sheet in the length segment Xi starting from the rear end of the glass, i.e., lowers its temperature at the pair of pressure rollers. The purpose of reducing heating in the rear edge region of the sandwich structure sheet is to enhance air evacuation at the pair of pressure rollers, thereby mitigating or even eliminating the aforementioned bubble problem in laminated glass. Air evacuation is enhanced because there will be more air evacuation paths when the film is colder and less tightly adhered to the glass or another film. Even at the rear edge of the sandwich structure sheet in the pair of pressure rollers, the film temperature must be sufficient so that the material layers will adhere tightly to each other once the air is removed. This method aims to reduce the temperature of the plastic film in the rear edge region of the sandwich structure sheet by at least 1°C, preferably at least 3°C, at the end of heating relative to heating without this method. The target temperature reduction depends on the overheating level of the rear part of the sandwich structure. Importantly, the bonding temperature of the plastic film pressed by the pressure rollers must be sufficiently high. For example, even at the back of a sandwich structure sheet, the bonding temperature of the PVB film pressed by a pair of pressure rollers must be at least about 60°C, which is also a suitable minimum temperature for many other film materials.

[0027] Typically, this invention aims to reduce heating in the last half of the sandwich structure sheet. The purpose of reducing heating at the rear edge of the sandwich structure sheet is specifically to lower the temperature of the last 150 mm section of the rear edge, which tends to overheat relative to sections further away from the rear edge. Excessive overheating causes the films to adhere prematurely, preventing air from escaping between the glass and the films or between the two films during the pressing stage as the sandwich structure sheet travels through a pair of pressure rollers. One cause of the aforementioned overheating is the additional heat transfer zone along the thickness dimension of the sandwich structure at the edges. The most common sandwich structure sheet thickness ranges from 6 mm to 25 mm, but thicknesses can reach up to 150 mm. The further the aforementioned overheating effect extends from the rear end, the thicker the sandwich structure sheet. It can be noted that this effect extends particularly from the rear edge to the longitudinal section of the thickness dimension of the sandwich structure, and at least slightly to a section two to three times its length. At the rear edge of the sandwich structure, the temperature of the plastic film can be up to 20°C-30°C higher than that closer to the center of the sandwich sheet, where the temperature difference decreases rapidly as the rear edge is moved from the center of the glass length. This invention reduces this overheating in the rear edge region and thus attempts to prevent or reduce premature sealing of the edge at the rear end of the sandwich sheet, where air, especially moisture, tends to escape during pressing with a pair of pressure rollers.

[0028] Cutting off or reducing heating can be done in several ways.

[0029] The laminator includes a device for preventing overheating of the sandwich structure sheet. According to a preferred embodiment, the device for preventing overheating is one that prevents airflow towards the air outlet of the air blowing box. According to another preferred embodiment, the device for preventing overheating of the sandwich structure sheet is one that prevents the impact of air jets discharged from the air outlet of the air blowing box towards the sandwich structure on the sandwich structure sheet.

[0030] Figure 3 A scheme according to one embodiment is shown, wherein airflow is prevented from entering the blowing box by means of a baffle 8. In this way, the supply opening of the blowing box can be blocked when it is desired to prevent jetting from the blowing box toward the sandwich structure. By partially blocking the supply opening of the blowing box, the air jet discharged from the blowing box toward the sandwich structure can be reduced. The baffle 8 is preferably a flap valve, wherein rotation of the valve flap throttles the supply opening of the blowing box.

[0031] Figure 4 Another embodiment is shown in which the baffle 9 moves in front of the air jet to prevent the air jet exiting from the blowing orifice of the blowing box from impacting the sandwich structure. The baffle can also be localized, thus reducing the jet impact with the sandwich structure.

[0032] Figure 5 A third embodiment is shown, comprising a perforated plate 10 having holes similar to or larger than the air orifices within the air-blowing box. When it is desired to prevent jetting, the perforated plate moves in the Z direction, in which case the holes in the perforated plate are no longer located at the air orifices of the air-blowing box, but instead block them, thereby preventing jetting from the air-blowing box. Similarly, jetting can also be reduced only when the unperforated portion of the perforated plate partially blocks the air orifices.

[0033] The hot air jet can also be cut off or reduced in other ways than those described above. From the perspective of the invention, it is important that the actuator that cuts off or reduces the hot air jet is fast enough. The actuator preferably cuts off or reduces the hot air jet as needed in less than one second, more preferably in less than 0.5 seconds. The actuator is preferably electric or pneumatic. The upper and lower air boxes, or their baffles 8, baffles 9, or perforated plates 10, are preferably mechanically connected to each other so that the jets on the upper and lower surfaces of the sandwich structure sheet can be cut off simultaneously by a single actuator. If the upper and lower air boxes have the same supply opening, this can be accomplished using a single baffle 8.

[0034] In a preferred embodiment of the invention, in the heating furnace, at the latest when the rear edge of the sandwich structure sheet approaches a distance of up to 150 mm (i.e., Xi at most 150 mm), or at the distance of the air gap L1 in the air blowing box, at the air blowing orifice section, or at the impact line of the air jet from the air blowing orifice row on the surface of the sandwich structure sheet, the hot air jet directed at the sandwich structure sheet is cut off, reduced, or prevented from impacting the sandwich structure sheet. According to another preferred embodiment, when the rear edge of the sandwich structure sheet approaches the air blowing orifice section or the impact line of the air jet from the air blowing orifice row on the surface of the sandwich structure sheet at a maximum distance of half the length of the sandwich structure sheet, the hot air jet directed at the sandwich structure sheet is cut off, reduced, or prevented from impacting the sandwich structure sheet. According to another preferred embodiment, when the rear edge of the sandwich structure sheet approaches the air inlet section at a maximum distance corresponding to three times the thickness of the sandwich structure sheet or 450 mm, the hot air jet pointing towards the sandwich structure sheet is cut off, reduced, or prevented from impacting the sandwich structure sheet.

[0035] In this heating furnace, as described above, when the rear edge of the sandwich structure sheet approaches the air-blowing orifice section, the hot air jets from at least one air-blowing orifice section above and below the sandwich structure sheet are cut off, reduced, or prevented from impacting the sandwich structure sheet. Then, at least one air-blowing box above and below the sandwich structure sheet is provided with a sealing device. This ensures that there is no significant temperature difference between the upper and lower surfaces of the sandwich structure sheet in the rear edge region during pressure rolling. Cutting off, reducing, or preventing the impact of the aforementioned hot air jets preferably occurs simultaneously on both sides of the sandwich structure sheet. In this case, the air-blowing boxes with sealing devices are located at the same roll gap point in the heating furnace.

[0036] According to a preferred embodiment, the heating furnace includes a plurality of air-blowing orifice sections (e.g., air-blowing boxes). When the rear edge of the sandwich structure sheet approaches the air-blowing orifice sections, the hot air jets in at least two of the air-blowing orifice sections are cut off, reduced, or prevented from impacting the sandwich structure sheet. According to an even more preferred embodiment, the heating furnace includes at least eight consecutive air-blowing orifice sections. When the rear edge of the sandwich structure sheet approaches the air-blowing orifice sections, the hot air jets in at least half of the at least eight consecutive air-blowing orifice sections are cut off, reduced, or prevented from impacting the sandwich structure sheet. In this embodiment, at least half of the air-blowing boxes are provided with closure devices, by means of which the air jets from the air-blowing boxes toward the sandwich structure sheet can be reduced or prevented. According to a preferred embodiment, the measured value of the air-blowing orifice section of the air-blowing box provided with the closure device is at most 200 mm or one roller gap in the direction of movement of the sandwich structure sheet.

[0037] By this method, heating of the rear end of the sandwich structure sheet can preferably be reduced in more than one step. Then, when the rear edge of the sandwich structure sheet approaches a distance Xi from the air vent section, the impact of the hot air jet from one air vent section on the sandwich structure sheet is cut off (or reduced), and when the rear edge approaches a distance Xi-STEP from another air vent section, the impact of the hot air jet from the second air vent section on the sandwich structure sheet is cut off. Therefore, in the heating furnace, when the rear edge of the sandwich structure sheet approaches the air vent section at various distances, the hot air jets from at least two air vent sections are cut off, reduced, or prevented from impacting the sandwich structure sheet. The difference in distance STEP is preferably at least 1 cm. This method can also achieve heating variations at the rear end of the sandwich structure sheet in more than two steps.

[0038] As the rear edge of the sandwich structure sheet approaches, the jetting in the blow-through section can be progressively reduced, for example, by using a baffle that blocks airflow towards the blow-through section at a slower rate than usual within time (Xi-FULL) / W, where FULL is measured from the rear end of the glass, and the maximum reduction is desired. In this way, and in the manner described above, the temperature can be reduced more directly at the rear end rather than slightly closer to the center of the sandwich structure sheet; that is, the temperature at the rear end of the sandwich structure sheet can be controlled even more precisely.

[0039] In the heating furnace according to the invention, the injection pressure of the air jet, i.e., the air pressure difference between the air blowing box and the heating furnace, is preferably 10 Pa to 100 Pa, the air temperature is preferably 150 °C to 250 °C, and the travel speed of the sandwich structure is preferably 0.5 m / min to 6 m / min.

[0040] By using the method and furnace according to the invention, the formation of bubbles can be substantially prevented compared to current methods and furnaces on the market.

[0041] In the claims, laminated film refers to the plastic film used in the above description, but laminated film also covers other possible film materials besides plastic.

Claims

1. A method for laminating glass sheets, wherein at least one laminate is disposed between the glass sheets, and the resulting sandwich structure sheet is conveyed along a roller track to a heating furnace, wherein, The sandwich structure sheet moving in the heating furnace is heated by double-sided hot air jetting, which is performed by a plurality of consecutive air-blowing orifice sections. The air-blowing machine draws air from the furnace and blows the drawn air into an air-blowing box through an air distribution duct and through air-blowing orifices. The air jets exiting from the air-blowing orifices impact the sandwich structure sheet, and the heated sandwich structure sheet is conveyed between a pair of pressure rollers. In the heating furnace, when the rear edge of the sandwich structure sheet approaches the air-blowing orifice section, the hot air jetting in at least one air-blowing orifice section is cut off, reduced, or prevented from impacting the sandwich structure sheet.

2. The method according to claim 1, wherein, In the heating furnace, at the latest when the rear edge of the sandwich structure sheet approaches the air inlet section at a maximum distance of half the length of the sandwich structure sheet, the hot air jet of the at least one air inlet section is cut off, reduced, or prevented from impacting the sandwich structure sheet.

3. The method according to claim 1, wherein, In the heating furnace, at the latest when the rear edge of the sandwich structure sheet approaches the air inlet section at a maximum distance of 150 mm, the hot air jet from the at least one air inlet section is cut off, reduced, or prevented from impacting the sandwich structure sheet.

4. The method according to claim 1, wherein, In the heating furnace, at the latest when the rear edge of the sandwich structure sheet approaches the air inlet section at a maximum distance corresponding to three times the thickness of the sandwich structure sheet, the hot air jet from the at least one air inlet section is cut off, reduced, or prevented from impacting the sandwich structure sheet.

5. The method according to any one of claims 1 to 4, wherein, In the heating furnace, when the rear edge of the sandwich structure sheet approaches the air blowing orifice section, the hot air jets from the upper and lower air blowing orifice sections of the at least one sandwich structure sheet are cut off, reduced, or prevented from impacting the sandwich structure sheet.

6. The method according to any one of claims 1 to 4, wherein, The heating furnace includes multiple continuous air blowing orifice sections. When the rear edge of the sandwich structure sheet approaches the air blowing orifice section, the hot air jets in at least two of the air blowing orifice sections are cut off, reduced, or prevented from impacting the hot air jets with the sandwich structure sheet.

7. The method according to any one of claims 1 to 4, wherein, The air inlet section is a rounded rectangular air box that is substantially transverse to the direction of movement of the sandwich structure sheet, and the rounded rectangular air box includes one or more air inlet rows that are substantially transverse to the direction of movement of the sandwich structure sheet.

8. The method according to claim 1, wherein, In the heating furnace, the blowing pressure of the air jet is 100Pa-1000Pa, the air temperature is 150℃-250℃, and the traveling speed of the sandwich structure sheet is 0.5 m / min-6 m / min.

9. An apparatus for laminating glass sheets into sandwich structure sheets, the apparatus comprising a heating furnace, a pair of pressure rollers, and means for establishing position data on the sandwich structure sheet, wherein the heating furnace is provided with roller tracks, at least one air blower, a heating resistor, and an air distribution duct, and a plurality of consecutive air blowing boxes are arranged above and below the roller tracks, characterized in that, The at least one air blower draws air from the furnace and blows the drawn air into the air blowing box through the air distribution duct and through the air blowing orifice. The air jet discharged from the air blowing orifice impacts the sandwich structure sheet. The at least one air blowing box is provided with a sealing device. When the rear edge of the sandwich structure sheet approaches the air blowing box, the sealing device can reduce or prevent the air jet from the air blowing box towards the sandwich structure sheet.

10. The device according to claim 9, wherein, At least one air box above and below the sandwich structure sheet is provided with a sealing device, which reduces or prevents air jetting from the air box toward the sandwich structure sheet when the rear edge of the sandwich structure sheet approaches the air box.

11. The device according to claim 9, wherein, The heating furnace includes at least eight consecutive air-blowing boxes, at least half of which are equipped with a sealing device to reduce or prevent air jetting from the air-blowing boxes toward the sandwich structure sheet.

12. The device according to claim 9, wherein, The supply opening of the air box has a movable baffle (8), by means of which the airflow entering the air box can be reduced or prevented.

13. The device according to claim 10, wherein, A movable baffle (9) is provided outside the air blowing box, which can reduce or prevent the impact of the air jet discharged from the air blowing port of the air blowing box.

14. The device according to claim 10, wherein, A movable perforated plate (10) is provided inside the air blowing box, which can reduce or prevent the discharge of air jets from the air blowing port of the air blowing box.

15. The device according to claim 10, wherein, The measured value of the air inlet section of the air box equipped with a sealing device is at most 200 mm or one roller gap in the direction of movement of the sandwich structure sheet.

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