MXPA97008895A - Process and system to temperate vid - Google Patents

Abstract

A system for tempering glass sheets having a preheating zone in which several stacked glass sheets, vertically, in the car divided into compartments are heated together at a temperature below the tempering temperature, for example 650 degrees centigrade (for example 300 degrees Celsius). The preheated glass sheets move individually from the preheating zone to the heating zone. In the heating zone the glass sheets are heated up to the tempering temperature, they are inclined towards the vertical in a sharp angle and are supported by air mattresses between the two heating sheets. At the lower edge of the two heating sheets of the heating zone there is a transport device that supports the glass sheets simultaneously in its bottom part. The glass sheets heated to the tempering temperature are moved to the cooling zone having cooling sheets aligned parallel to the heating sheets and between which the glass sheet is placed for rapid cooling. The cooling sheets can also be placed on the sides of the glass sheet that is to be cooled quickly in order to cool it quickly. The rapidly cooled glass sheets, which still have a temperature of, for example, 300 degrees centigrade, are transported to the subsequent cooling zone in which they are cooled slowly to room temperature, then deposited in the compartmentalized carts. Because the glass sheets are placed in the cooling zone obliquely, and not horizontally, there are no problems with the support and transport of the glass sheets. The preliminary pre-heating of the glass sheets and the joint cooling of the glass sheets to room temperature after rapid cooling is a considerable energy saving since the heating and cooling energy in the preheating zone and in the preheating zone can be reduced. the cooling zone posteri

Description

Process and system for tempering glass The invention relates to a process having the characteristic of the introductory part of the preamble of claim 1. Furthermore, the invention relates to a system (device) with the features of the introductory part of the claim of the independent apparatus. The glass sheets are tempered by heating them to a temperature (tempering temperature) above 650 degrees Celsius and then rapidly cooling to a temperature that is below the critical temperature, for example less than 300 degrees centigrade, so such that the stresses that temper the glass are formed due to the impact by cooling. In known devices the cost to heat the glass sheets and the costs of the rapid cooling are very high. In particular, in the known devices considerable amounts of energy are required to operate the fan that provides the hot gases to heat the glass sheets. The aim of the invention is to improve the tempering of glass and the systems provided for this purpose in such a way that the cost in energy and time is reduced and still a good tempering of the glass is achieved.

# According to what is claimed in the invention this objective is achieved with the characteristics of the claimed main process. In relation to the proposed system (device) as claimed in the invention, the objective 5 is achieved with the features of the independent claim of the main apparatus. Large amounts of time and energy are saved, since in the invention, the glass sheets are heated JÉ previously, for example together and then warm up to the The tempering temperature preferably preferably required individually and in addition rapid cooling, to a temperature below the critical temperature, is preferably done individually, and then the glass sheets are cooled, for example together, to room temperature, 15 large quantities, because it is only necessary that the heating and cooling zones are short. The invention is based on finding that this is sufficient to temper the glass sheets if the temperature rise, from the tempering temperature, for example 650 degrees 20 centigrade, to a temperature below the critical temperature, for example about 300 degrees centigrade, is carried out rapidly to achieve the desired tempering effect. Then, the previous heating and cooling to room temperature can be done 25 slow manner without presenting any adverse effect in the tempering of the glass sheets. The adverse stresses of the non-uniform surface are avoided, which leads to undulations in the glass sheets that are formed in the known processes. Other details and features of the invention result from the following description of the system for annealing the glass sheets shown by means of the example in the drawings. Figure 1 shows the entire system in an oblique view and Figure 2 shows the heating and cooling zone in an enlarged view. The system, as claimed in the invention, shown in Figure 1 consists of four zones, specifically the previous heating zone 1, the heating zone 2, the cooling zone 3 and the area after the cooling 4. the preheating zone 1 which is housed in the closest chamber 5, the glass sheets 7 remain on shelves, for example trolleys divided into compartment 6, are preheated together and heated, for example, to a temperature of about 300 degrees Celsius. The trolleys divided into compartments 6 used in the preheating zone 1 can have a construction as is known from EP 603 151 A or EP 704 389 A. Only the side s rollers or the sleeve-shaped sliding parts of the trolleys divided into compartments 6 is made of a material resistant to temperature due to the tension of the 5 high temperature. As shown in Figure 1, the carriages divided into compartments 6 are guided to move on rails 8, aligned transversely to the compartments É) which hold the glass sheets 7 and which are provided in 10 the carriages, in such a way, that the previously heated glass sheet, selectively, 7 can be delivered to the reclining table 9, from which it is transported in the inclined position, which corresponds to the heating zone 2. from the preheating chamber 5 15 to the heating zone 2. The tilting table 8 advantageously is made with a fe-elaborated support surface as an air-cushion wall. According to one embodiment, between the preheating chamber 5 in which the glass sheets 7 are preheated together, and the heating zone 2 in which the glass sheets 7 are heated individually, for example to a temperature of 650 degrees centigrade, there may be other heating zone in which the glass sheets 7 are individually heated to a temperature between the temperature in the preheating chamber 5 and that of the heating zone 2. However, this embodiment is not shown in the drawings. An advantage of the pre-heating chamber, in which several sheets of glass 7 are heated together, is that the heating can be carried out slowly and, therefore, with a low energy consumption, since there is sufficient time for the pre-heating Thus, in the embodiment, it is shown that in chamber 5 there are several, for example, two cars divided into compartments 6 and that the car divided into compartment 6 which is loaded with glass sheets 7 and finally moves towards the chamber Preheating 5 only moves to the removal point provided below to tilt the table 9 when the cars divided into compartments 6, located at the point of removal, has been emptied. Then, a new car divided into compartments 6, which is filled with sheets of glass 7, is directed towards the waiting area of the preheating chamber 5 and the glass sheets 7 located therein are heated slowly. The heating zone 2 is shown in Figure 2 in more detail. In contrast to the known heating zones for heating the glass sheets in its tempering zone by heating 2, as claimed in the invention, it is aligned in such a way that the glass sheets 7 are aligned, not horizontally but inclined almost vertically. To do this, the heating zone 2 (as well as the cooling zone 3, downstream) is aligned with the inclined adjustment 11, for example in the form of pneumatic or hydraulic cylinders, so that the inclination of the zone of heating 2 or the glass sheets 7 located therein can be adjusted according to the requirements (size and thickness of the glass sheet). In this way, the transport and support problems of the glass sheets (deformation / sags) occurring in the heating zones with the horizontal glass sheets are avoided. For support at the lower edges of the glass sheets 7 there is a transport device 12 which, as shown in the embodiment., Can be a continuous conveyor belt or belt, but it can also be a transport device that it is done according to the principle described in DE 30 38 425 A, in which the horizontal support of the conveyor mechanisms can reach totally or partially the bottom part of the glass sheets 7 at its lower edge. Preferably, the supports that reach the bottom of the glass sheets 7, especially, when they reach the bottom part of the glass sheets in their entirety, are gripped or joined leaving one of the other in opposite or opposite chains. other elements of the continuous conveyor. In the embodiment, the heating zone 2 is shown, which has two opposite heating foils 15 which leave a space or separation between them for the glass sheets 7 to be heated and which can be heated in this way. For example, the heating system can be an electric heating system or a gas heating system. In the heating foils 15, which can additionally have a surface made to increase and support the emission of the heat radiation, having a series of orifices 16 that can be charged with pressurized air, by means of the chamber 17, of such that both sides of the glass sheet 7 located between the heating sheets 15, gas mattresses, especially air mattresses, are formed. Therefore, the glass sheet 7 touches one or another heating sheet 15, but is simply supported and transported at its lower edge by the transport mechanisms 12. An embodiment of the heating sheets 15 is conceived in the which the heating foil 15 located on top of the glass sheets 7 does not have holes 16, so that the heat is released for the most part by heat radiation from the upper heating foil 15 in the glass sheet 7 which is it's going to heat up Therefore, in the invention, the heating zone 2 can be made such that as the heating sheet 15 decreases the heat is first released in the glass sheet by radiation and convection, from the upper glass sheet 15 mainly by radiation. To supply the gas to the heating sheets 15 to form the air cushion, in compressed gas, suitably preheated, for example air, can be supplied to the chambers 17. But it is also possible to form the air cushion by the combustion of gases that are formed when the gas is burned, the combustion heat is used at the same time to heat the heating sheets 15. To adapt to different sizes of glass sheets, the heating sheets 15 can be divided into sections that extend, for example parallel to the transport device 12, therefore in the direction of transport, and which, depending on the length of the glass sheet 7 measured outside the transport device 12, can be started or started and stopped. This saves even more energy. The heating sheets 15 are also constructed in the device, in a manner not shown, such that the distance of the heating sheets 15 from each other can be changed to adapt to the thickness of the glass sheet to be temper. It is sufficient to do this, if the upper heating foil 15 is adjusted, for example, by means of hydraulic cylinders or similar servo-actuators, relative to the lowermost heating foil 15. Because the heating zone 2 is formed in accordance as claimed in the invention, the glass sheet 7, for example, is rapidly heated from the previous heating temperature of 300 degrees centigrade to the tempering temperature of for example 650 degrees centigrade mainly by radiation, supported by convection. Adjacent to the heating zone 2 there are cooling zones 3 which are made identical to the heating zone 2 in terms of the construction, and in this there are cooling sheets 20, through which, for example, a means of cooling flows (not shown). The outlet orifices 16 in the two cooling sheets 20 are charged with a corresponding cooled gas so that the now cold air mattresses, which were described above together with the heating zone 2, are formed and are located above and below. of the glass sheet 7 # to be cooled rapidly, or only under the glass sheet 7. The cooling sheets 20 are made in a similar way to move in relation to the other, so that 5 can approach each other or separate. This can also be used to place the cooling foils 20, briefly, on both surfaces of the glass sheets 7 while the air cushion is turned off and the transport 12 ato stops, in order to accelerate the cooling 10 fast for purposes of tempering the glass sheet 7. This approach is preferably used in thin glass sheets 7. For thicker glass sheets 7, it is often advantageous to provide cold air to the glass sheets 7, which are going to temper, usually by 15 both sides, and stop the glass sheets 7 in the area of the cooling zone 3. When the cooling sheets 20 are placed in the glass sheets 7, the transport 12, in the area of the cooling zone 2, stops to avoid a movement 20 relative between the glass sheet 7 and the transport 12. It should be noted that the transport 12 can be stopped in the area a of the heating zone 2 also if, for example, the glass sheets 7 are so large and / or thick ff that can not be heated up to the tempering temperature required in a continuous operation. After the cooling zone 3, the glass sheets 7, via the tilting table 25, reach the area 5 of subsequent cooling 4, which can be housed in a chamber and which likewise contains the compartmented trolleys 6 of the aforementioned type, in which the glass sheets 7 can be deposited by a kind of Is consignment in cars divided into compartments 6, 10 to then cool them to room temperature. At this point, it is not necessary that the power or cooling energy be greater, since there is enough time to cool down. Similarly, it is possible when the rear cooling zone 4 is housed in a chamber (see chamber__ in Figure 1). 15 illustrated that with broken or dotted line), supply hot air from the rear cooling zone 4 to F the previous heating zone 1 to save energy (pipes 26). The surfaces of the cooling sheets 20 facing the glass sheets 7 can be made to withstand the absorption of the heat radiation. For example, the surfaces of the cooling sheets 20 that are facing each other can be made interwoven or wavy to increase the area of the cooling sheets that absorb heat.

In the system claimed in the invention, the glass sheets 7 move, without being in a horizontal position, but inclined towards the vertical, for example, at an acute angle, through the heating zone and downstream towards the cooling zone 3, such that in the system, as claimed in the invention, the above problems do not arise, together with the support of the glass sheets 7 and their transport, which frequently leads to deformations of the sheets of glass. glass 7. By means of the transport devices 12 which engage the lower edge of the glass sheets 7, the latter can be moved at the desired speed through the heating zone 2 and the cooling zone 3, it is possible and really easy to stop the glass sheets 7, if necessary, in the heating zone 2 and / or in the cooling zone 3 for a short period of time; this is of special interest when in the cooling zone 3 the cooling sheets 20 are placed on both sides of the glass sheet 7 which is to be cooled rapidly. Thus, like the heating sheets 15, the cooling sheets 20 can also be divided into several zones in such a way that the area of the cooling sheets 20 that are activated to cool them can be adapted to the size of the glass sheet 7 that is going to cool quickly (its longitudinal extension is measured far from the means of transport). To avoid the need to continuously turn on and off the different zones of the heating sheets 15 and / or the cooling sheets 20, it is possible to proceed in such a way that the glass sheets 7 with the same or very similar length or height can be removed from the preheating zone 1 and sent in succession through the heating zone 2 and the cooling zone 3 The tempered glass sheets 7 can again be classified by consignment in the cooling zone 4. In summary, an embodiment of the invention is described below. A system for tempering glass sheets has a preheating zone 1 in which several sheets of glass 7 are stacked vertically, in the divided car in compartments 6 they are heated together to a temperature below the tempering temperature of, for example 650 degrees centigrade (for example 300 degrees Celsius). The preheated glass sheets 7 are directed, individually, from the preheating zone 1 to the heating zone 2. In the heating zone 2, the glass sheets 7 are heated up to the tempering temperature, where they are tilted at vertical direction until reaching an acute angle and being supported by air mattresses between the two heating sheets. At the lower edge of the two heating sheets of the heating zone 2 there is a transport device that supports the glass sheets 7 simultaneously at the bottom. The glass sheets 7 heated to the tempering temperature are moved to the cooling zone 3 having cooling sheets aligned parallel to the heating sheets and between which the glass sheet 7 is placed to be rapidly cooled. The cooling sheets can also be placed on the two sides of the glass sheet 7 to be tempered for the purpose of rapid cooling. The rapidly cooled glass sheets, which still have a temperature of, for example, 300 degrees centigrade, are transported to the rear cooling zone 4 in which they are slowly cooled to room temperature from where they are deposited in the compartmented cars. Because the glass sheets 7 are placed in the heating zone 2 and in the cooling zone 3 obliquely, and not horizontally, there are no problems with the support and transport of the glass sheets 7. The previous heating assembly of the glass sheets and the joint cooling of the glass sheets 7 up to the ambient temperature from their rapid cooling, saves considerable energy, since the energy for heating and for cooling in the previous heating zone 1 and in the rear cooling zone 4 can be slow.

Claims (34)

Claims

1. The process for tempering glass sheets in which the glass sheets are heated to a temperature above the tempering temperature and cooled to a temperature below the critical tempering temperature, characterized in that the glass sheets are preheated until the temperature close to the critical temperature, the sheets of glass previously heated in this way are heated to a temperature above the tempering temperature, the glass sheets are quickly cooled to a temperature below the critical temperature, and then the Glass sheets are cooled to room temperature.

2. The process according to claim 1, wherein the glass sheets are preheated together with several sheets of glass.

3. The process according to claim 1 or 2, in which the preheated glass sheets are individually heated to the temperature above the tempering temperature and cooled rapidly, also individually, from this temperature to the temperature below of the critical temperature.

4. The process according to claims 1 to 3, wherein the glass sheets are cooled together to room temperature for several glass sheets.

5. The process according to one of claims 1 to 4, wherein the glass sheets are aligned at an acute angle to their vertical when they are heated to the temperature above the tempering temperature and when they are rapidly cooled to the temperature below the critical temperature.

6. The process according to one of claims 1 to 5, wherein when the glass sheets are heated and cooled they are placed in a heating zone and a cooling zone bordered by heating sheets and cooling sheets respectively less from below by means of compressed gas mattresses and they are supported and transported on their horizontal edge.

7. The process according to one of claims 1 to 6, wherein the glass sheets to be tempered are heated to a temperature of about 650 degrees centigrade.

8. The process according to one of claims 1 to 7, wherein, during tempering, the glass sheets are rapidly cooled to a temperature below 300 degrees centigrade.

9. The process according to one of claims 1 to 8, wherein the glass sheets before being heated are preheated to a temperature above the tempering temperature up to the temperature of about 300 degrees centigrade.

10. The process according to claims 1 to 9, in which the gas pressure cushion is formed in the area of the heating zone by hot air or combustion gases.

11. The process according to one of claims 1 to 10, wherein the pressurized gas cushion is formed in the area of the cooled air cooling zone.

12. The process according to one of claims 1 to 11, wherein the sheets around the cooling zone are placed on the glass sheet on both sides to cool it rapidly.

13. The process according to one of claims 1 to 12, wherein the glass sheets are transported through the heating zone and / or the cooling zone at a rate that depends on the 5 thickness and optionally, it stops temporarily in the heating zone or in the cooling zone.

14. The process according to one of claims 1 to 13, wherein the hot air • 10 emitted from the rear cooling zone is used to heat the previous heating zone.

15. The process according to one of the claims 1 to 14, wherein the heating in The heating zone is preferably carried out by the convection caused by the compressed gas supported by radiation.

16. The device for executing the process according to claims 1 to 15, which has a heating zone and a cooling zone downstream, in which there are heating sheets or cooling foils that are separated from each other and which include an acute angle with respect to the vertical, and in 25 where in front of the heating zone is the pre-heating zone and after the cooling zone is the rear cooling zone.

17. The device according to the 5 claim 16, in which the mutual distance of the heating sheets in the heating zone and the mutual distance of the cooling sheets in the cooling zone can change. F 10

18. The device according to claim 16 or 17, wherein the lower edge of the heating sheets and at the lower edge of the cooling sheets there is a transport device.

19. The device according to one of claims 16 to 18, wherein the inclination of t- the heating sheets and the cooling sheets with respect to the vertical may change.

20. The device according to one of claims 16 to 19, wherein the preheating zone comprises the preheating chamber and wherein in the preheating chamber there are shelves for securing several sheets of glass that they are going to 25 suffer the previous heating at the same time.

21. The device according to one of the claims from 16 to 20, wherein the rear cooling zone optionally comprises a rear cooling chamber and in the rear cooling zone there are shelves to hold several sheets of glass that are going to cool at the same time.

22. The device according to one of the claims from 16 to 21, wherein at least in the heating sheets located under the glass sheets to be heated there are holes for the outlet of the compressed gas in order to form an air mattress between the heating sheet and the glass sheet to be heated.

23. The device according to one of claims 16 to 22, wherein the cooling sheet is placed under the glass sheet to be cooled, but preferably in two cooling sheets on the surfaces in front of the sheet There are holes in the glass to let the cooled gas out to form air mattresses between the cooling sheets and the glass sheet that is going to cool quickly.

24. The device according to one of claims 16 to 23, wherein the heating sheets are equipped with an electric heater.

25. The device according to one of claims 16 to 23, wherein the heating sheets are heated by the combustion of gases of at least one gas burner.

26. The device according to one of claims 16 to 25, wherein the combustion gases pass through the outlet orifices in the heating sheets.

27. The device according to one of the claims from 16 to 26, in which between the shelves for fastening the glass sheets in the preheating chamber and the heating zone there is a tilting table for rotating the glass sheets towards an oblique position of the heating zone.

28. The device according to one of claims 16 to 27, wherein in the rear cooling zone there is an inclination table for aligning the glass sheets from the inclined position of * the cooling zone to the position at which can be deposited in the compartments of the shelves in the subsequent cooling zone.

29. The device according to one of claims 16 to 28, wherein the shelves in the preheating chamber and / or the subsequent cooling chamber are made as carriages divided into compartments that move transversely towards the chamber. 10 transportation address.

30. The device according to one of claims 16 to 29, wherein there is a line that joins the ventilation openings of the chamber 15 subsequent cooling with the pre-heating chamber.

31. The device according to one of claims 16 to 30, wherein the heating sheets are divided into several sections that can be 20 heating independently of each other.

32. The device according to one of claims 16 to 31, wherein the sheets of the cooling zone are divided into several sections that can be cooled independently of one another. 25

33. The device according to claim 31 or 32, wherein the heating sheets and / or the cooling sheets are divided into sections in the form of bands extending parallel to the transport direction at the lower edge of the heating zone and / or the cooling zone.

34. The device according to one of claims 16 to 33, in which between the preheating zone in which several sheets of glass are preheated at the same time and the heating zone there is a device for additional heating of the sheets of glass individually. Process and system for tempering glass Summary A system for tempering glass sheets having a preheating zone in which several sheets of stacked glass, vertically, in the car divided into compartments are heated together at a temperature below the tempering temperature, for example 650 degrees centigrade (for example 300 degrees Celsius). The preheated glass sheets move individually from the preheating zone to the heating zone. In the heating zone, the glass sheets are heated up to the tempering temperature, are inclined towards the vertical at an acute angle and are supported by air mattresses between the two heating sheets. At the bottom edge of the two heating foils of the heating zone there is a transport device that supports the glass sheets simultaneously at its bottom part. The glass sheets heated to the tempering temperature are moved to the cooling zone having cooling sheets aligned parallel to the heating sheets and between which the glass sheet is placed for rapid cooling. The cooling sheets can also be placed on both sides of the glass sheet that is to be cooled quickly in order to cool it quickly. Rapidly cooled glass sheets which still have a temperature of, for example 300 degrees centigrade, are transported to the subsequent cooling zone in which they are cooled slowly to room temperature after they are deposited in compartmented cars. Because the glass sheets are placed in the heating zone and in the cooling zone obliquely, and not horizontally, there are no problems with the support and transport of the glass sheets. The initial preheating of the glass sheets and the joint cooling of the glass sheets to room temperature after the rapid cooling is a considerable energy saving since the heating and cooling energy in the pre-heating zone can be reduced. in the rear cooling zone. IFig 1)