Method and system for solidifying and / or hardening glass

Abstract

The invention relates to a method for solidifying and / or hardening glass, wherein the glass is brought into contact with a liquid salt. The method is characterized in that thermal energy is continuously transferred exclusively from the glass to be solidified and / or hardened to the liquid salt. The invention further relates to a system for solidifying and / or hardening flat glass.

Description

[0001] 1

[0002] Method and equipment for strengthening and / or hardening glass

[0003] The invention relates to a method for solidifying and / or hardening glass, in which glass objects are continuously brought into contact with a liquid salt.

[0004] The invention also relates to a system for solidifying and / or hardening glass, in which the glass is brought into contact with a liquid salt.

[0005] It is known that the breaking strength of glass can be increased by a process called thermal tempering (also commonly referred to as thermal hardening or annealing). In this process, the glass workpiece to be strengthened is heated in a furnace to approximately 680 °C and then rapidly quenched to room temperature. This quenching causes the surface to solidify, and the external dimensions of the component then change only minimally. Internal stresses are created within the glass workpiece, resulting in increased breaking strength.

[0006] From DD 1579 66, a method and a device for strengthening glass products by ion exchange are known. The glass products are strengthened by alkali ion exchange between the glass surface and molten alkali salts. For strengthening, hollow glass products with downward-facing openings or hollow glass products rotated or pivoted about a horizontal axis are sprinkled with the molten salt. The salt is continuously circulated and passed through perforated plates to create a cascade of rain for the glass products arranged in several layers. A disadvantage of this method is only economically viable when using comparatively expensive specialty glass.

[0007] From DE 1 5 10 202 02, a process for the production of hollow glass bodies with increased mechanical strength is known using the blow-blow and press-blow forming processes. The process is characterized by the addition of mist-like aqueous alkali metal salt solutions to the blowing compressed air in the pre- and / or final mold of the blow-blow forming process or in the final mold of the press-blow forming process.

[0008] From DE 1 1 2014 003 344 T5, a chemically tempered glass for flat panel displays of digital cameras, mobile phones, digital organizers, etc., is known. The chemically tempered glass has a pressure-resistant layer produced by an ion exchange process, wherein the glass has a surface roughness of 0.20 nm or higher and wherein the hydrogen concentration Y in the range to a depth X from an outermost surface of the glass satisfies the equation Y = aX + b at X = from 0.1 to 0.4 (pm). The glass is preheated to a temperature of 100°C and then immersed in molten salt.

[0009] From WO 2022 049205 Al, a flat glass sheet is known which is made from a base material that is an alkali-containing silicate glass. The flat glass sheet is characterized in that at least one surface layer is enriched in potassium and depleted in sodium and / or lithium, while an inner layer, in particular one directly adjacent to the surface layer, is neither enriched in potassium nor depleted in sodium and / or lithium, and that the flat glass sheet exhibits compressive stress down to a certain depth and tensile stress from that depth onwards, wherein the tensile stress increases with increasing depth up to a maximum tensile stress located in the inner layer, and / or wherein the tensile stress profile does not have a linear section as a function of depth, and / or wherein the tensile stress profile does not have a section in which the tensile stress is constant as a function of depth.

[0010] A chemical hardening process is known from US Patent 3,628,934 A. In this process, glass sheets are transported lying down in racks and immersed in a bath of molten potassium.

[0011] US patent 2019 / 055152 AI discloses a system for the thermal hardening of glass and glass-ceramics. In this system, glass sheets are guided between opposing fluid reservoirs. The fluid reservoirs have openings through which the fluid flows.

[0012] From CA 3 193 626 A1, a method for increasing the strength, in particular the flexural strength, of a glass article made from a glass material is known. The method includes the step of heating the glass article to a first temperature above the transformation temperature of the glass material, the step of shock-cooling the glass article to a second temperature below the transformation temperature of the glass material, and the step of carrying out an ion exchange process at the second temperature.

[0013] The object of the present invention is to provide a method which exhibits high process stability and process safety.

[0014] The problem is solved by a method of the type mentioned above, which is characterized in that heat energy is transferred to the liquid salt exclusively from the glass to be solidified and / or hardened.

[0015] A further object of the present invention is to provide a system that enables high process stability and process reliability. 3

[0016] The problem is solved by a system of the type mentioned above, which is characterized in that the system is designed in such a way that heat energy is continuously transferred exclusively from the glass to be solidified and / or hardened to the liquid salt.

[0017] In accordance with the invention, it was recognized that the conventional method for solidifying and / or hardening glass is disadvantageous, in which a heating device is not only used to initially melt the salt, but in particular to heat the already liquid salt during the solidifying and / or hardening process.

[0018] In particular, it was recognized that a constant temperature of the liquid salt is crucial for process stability and reliability. However, it has not yet been considered that conventional systems, where the glass is cooled with the salt, ultimately have two competing heat sources: the aforementioned heating device and the heat input from the glass itself. It has been shown that setting and maintaining a precise target temperature for the solidification and / or hardening process is problematic, even with a complex control system that balances and regulates these two heat sources simultaneously. In systems with a direct heating device, unpredictable temperature fluctuations can occur, leading to uneven solidification and / or hardening.The combination of the two heat sources can even lead to nonlinear effects and unexpected interactions, making the behavior of the control loop unpredictable.

[0019] Within the scope of the present invention, the phrase "heat energy is transferred to the liquid salt exclusively from the glass to be solidified and / or tempered" means that no additional heat is applied to the salt during the execution of the process or during operation of the system. This means that the already liquefied salt absorbs the heat energy relevant for the tempering and / or solidification process solely through contact with the glass objects to be solidified and / or tempered. Minor, unavoidable energy inputs from the environment, such as heat radiation from a ceiling lamp in the hall where the system is located, or diffuse heat radiation from other system components, are not relevant within the meaning of the invention. The crucial point is that no additional, specifically used heat source is provided to actively supply the liquid salt with energy.It should be clarified that the present invention does not preclude a heating source for liquefying the salt. Such a heating source may be present to bring the salt into the liquid state before the start of the process. However, this heating source is not in operation during the execution of the process according to the invention. The invention relates to a phase in which glass objects are brought into contact with already liquefied salt.

[0020] The inventive method, in which the heat energy is transferred exclusively from the glass to the liquid salt and no direct heating device is used for the salt (except for the initial melting of the salt), offers several advantages.

[0021] In particular, the target temperature of the liquid salt can be set and kept constant very precisely without the need for complex control systems. Rather, the system according to the invention can have a comparatively simple control loop by means of which the temperature of the liquid salt can be regulated precisely and reliably. In particular, the problem of having to control a loop with two heat sources is eliminated.

[0022] Furthermore, the inventive system, which does not require an additional heating device during the solidification and / or hardening process, has the particular advantage of increased reliability and reduced maintenance, since (except for the initial melting of the salt) fewer components are used during the solidification and / or hardening process that could potentially fail.

[0023] Furthermore, based on the present invention, a very high energy efficiency can be achieved in a particularly advantageous manner, which is explained in detail below.

[0024] In an advantageous embodiment, the temperature of the liquid salt is regulated in a control loop to a predetermined or predeterminable target temperature.

[0025] To maintain a constant temperature of the liquid salt, the control loop can include the following elements: A temperature sensor, which can be placed, for example, in a pipe carrying the liquid salt or directly in a basin containing the liquid salt. The temperature sensor measures the current temperature of the liquid salt and sends this information to a controller, typically an electronic one. The controller processes the temperature signal from the sensor and compares the measured temperature with the target temperature. Depending on the difference between the measured temperature and the target temperature, the controller adjusts a manipulated variable within the control loop, which will be discussed in more detail below.

[0026] The required target temperature depends in particular on the type of glass material. The required target temperature also depends on the shape and volume of the glass objects to be solidified and / or tempered.

[0027] The process is particularly advantageous when carried out with glass consisting of an alkali-containing silicate glass, especially an alkali-earth silicate glass, or an aluminosilicate glass, or a borosilicate glass. Aluminosilicate glass has the particular advantage that especially break-resistant flat glass parts can be obtained with the process according to the invention. Borosilicate glass and alkali-earth silicate glass also have the particular advantage that very break-resistant glass parts can be obtained with the process according to the invention. These types of glass are particularly well suited for obtaining especially break-resistant glass parts using the process according to the invention. However, there are no fundamental restrictions regarding the type of glass. The process according to the invention can be flexibly used with various types of glass.

[0028] Controlling the salt temperature to a precisely defined target temperature allows the process to be optimally adapted to the specific properties of the glass being processed. In particular, different types of glass have specific thermal requirements that can be ideally met through flexible and precise temperature control.

[0029] The target temperature of the liquid salt can advantageously be in a range of 50 Kelvin to 200 Kelvin below the transformation temperature of the glass material.

[0030] A further advantage of the invention is that the entire solidification and / or hardening process can take place in a continuous production line, enabling high processing capacity. The system according to the invention can advantageously be designed to allow a continuous processing process in which glass parts pass through the various stations of the system without interruption. This means that the system is capable of processing glass in a continuous flow. In particular, several glass objects can be within the system simultaneously. Specifically, several glass objects can be in different phases of the process at the same time. This significantly increases throughput, as the system operates continuously and new glass objects can always be added to the process while others are already being processed or have been completed.

[0031] In particular, it can be generally advantageous to provide that the glass to be solidified and / or tempered is brought into contact with the liquid salt in a continuous flow. In a preferred embodiment of the process according to the invention, the glass to be solidified and / or tempered is brought into contact with the liquid salt in a continuous flow. A continuous flow means that the glass objects are not only introduced into the salt bath individually or in batches, but that a constant flow of glass is provided in which new glass objects continuously enter the liquid salt and are removed again after the required residence time. This can be achieved, for example, by conveying the glass objects through a salt bath using a conveyor device.The conveying device can, for example, consist of a conveyor belt and / or racks in which the glass objects are held. It is also possible to guide the salt as a liquid stream past a fixed position where the glass objects are located, so that contact occurs through the movement of the salt. A combination of both principles is also conceivable, in which both the glass objects are moved and a flow of salt is generated. The continuous flow has the advantage of enabling a uniform and reproducible process in which a large number of glass objects can be solidified and / or tempered with consistent quality. Furthermore, it allows for particularly economical continuous production without interruptions and reduces energy consumption, as the liquid salt is used optimally due to the constant throughput.

[0032] The glass to be strengthened and / or tempered is brought into contact with the liquid salt for a treatment period. This treatment period can advantageously range from 5 minutes to 300 minutes, particularly from 15 minutes to 45 minutes. Especially with glass objects made from the aforementioned types of glass, this method can achieve both strengthening and tempering because thermal stress and ion exchange occur simultaneously in the surface layers of the glass objects.

[0033] In particular, a basin filled with liquid salt may be present, into which the glass is immersed for a period of time for a hardening and / or curing process. Alternatively or additionally, it is also possible, for example, that bringing the glass to be hardened and / or cured into contact with the liquid salt involves sprinkling it with the liquid salt. There are no fundamental restrictions regarding the method of bringing the glass to be hardened and / or cured into contact with the liquid salt.

[0034] To control the temperature of the liquid salt, especially to a predetermined or setpoint temperature, different process variables (alone or in combination) can act as control variables.

[0035] In an advantageous embodiment, the amount of glass to be solidified and / or tempered that is brought into contact with the liquid salt per unit of time acts as a 7

[0036] Control variable of the control loop. For example, it can be advantageous to have a controller that regulates the transport speed of a conveying device that feeds the glass to the liquid salt, in order to ultimately control the amount of glass to be solidified and / or tempered that is brought into contact with the liquid salt per unit of time. This enables precise adherence to the process parameters, resulting in uniform and controlled solidification and / or tempering of the glass.

[0037] Alternatively or additionally, it can be advantageous to use the amount of heat energy extracted from the liquid salt per unit of time as a control variable in the control loop. For example, heat energy can be extracted from the liquid salt using a heat exchanger. By using the amount of extracted heat energy as a control variable, the control loop can be precisely controlled. This enables precise adherence to the process parameters, resulting in uniform and controlled solidification and / or hardening of the glass.

[0038] Furthermore, the possibility exists to utilize the heat energy extracted from the salt for other purposes, particularly within the solidification or hardening process or in glass production, thereby increasing the overall energy efficiency of the plant. This extracted heat energy can, for example, be used to heat other process areas or for other purposes in the glass production cycle, which reduces overall costs and energy consumption. The reuse of heat energy advantageously reduces the plant's need for external energy.

[0039] For example, it may be advantageous to provide that at least part of the extracted heat energy is used to heat already manufactured glass that needs to be strengthened and / or tempered.

[0040] In a particularly flexible design, at least some of the extracted heat energy is converted into another form of energy, especially electrical energy. By converting the extracted heat energy into electrical energy, a portion of the energy demand of the process or the system itself can be met. This reduces dependence on external energy sources. Electrical energy, in particular, can be used flexibly, for example, to power components of the system. Of course, it is also possible to sell the generated electrical energy and / or feed it into a public or private power grid.

[0041] The glass to be solidified and / or hardened is preferably heated to a starting temperature and then brought into contact with the liquid salt. 8

[0042] Heating can be advantageously achieved, for example, by microwave irradiation and / or by transport through an oven. More generally, the system can include a heating device designed to heat the glass to an initial temperature required for the hardening and / or solidification process.

[0043] In a particularly advantageous implementation, the initial temperature acts as a control variable in the control loop. Using the initial temperature as a control variable enables precise control of the liquid salt temperature, leading to uniform and consistent process results.

[0044] The initial temperature is above the minimum temperature of the liquid salt and preferably above the target temperature of the liquid salt. The initial temperature can advantageously be in the range of 100 Kelvin to 300 Kelvin above the transformation temperature of the flat glass and / or in the range of 50 Kelvin below and 30 Kelvin above the Littleton point of the glass material. Particularly when processing alkali-alkaline earth silicate glass, the initial temperature can advantageously be in the range of 700 to 760 °C, and especially in the range of 720 to 740 °C. Correspondingly, the temperature of the molten salt, which can be, for example, molten sodium salt or molten potassium salt, can be in the range of 350 to 500 °C, and especially in the range of 390 to 450 °C or in the range of 420 to 440 °C.

[0045] The Littleton point is the temperature at which the viscosity r|IO 66 Pa s (Pascal times second) is the unit of measurement.

[0046] The target temperature can advantageously be at least 200 Kelvin and at most 550 Kelvin, and in particular at least 200 Kelvin and at most 450 Kelvin, below the initial temperature. In particular, the target temperature can also be advantageously in a range of 50 Kelvin to 200 Kelvin below the transformation temperature of the glass material, as already mentioned above. This is particularly advantageous for glass articles to be strengthened and / or tempered, which consist of an alkali-containing silicate glass, in particular an alkali-earth silicate glass, or an aluminosilicate glass, or a borosilicate glass.

[0047] The glass to be consolidated and / or tempered can consist, for example, of glass containers or flat glass parts. There are no fundamental restrictions regarding the type of glass parts that can be treated with the method according to the invention. Within the scope of this patent application, the terms "glass objects" and "glass parts" are used synonymously. 9

[0048] The method according to the invention is suitable for treating glass components for a wide variety of applications. The treated glass components can, for example, be used as flat glass panes in windows, doors, and facades to achieve increased safety. The treated glass components can be glass panes for vehicles, particularly motor vehicles. The treated glass components can be used, for example, as a protective layer for smartphones, tablets, laptops, and other electronic devices. Solar modules represent another field of application. The treated glass components can be used in solar modules to protect the sensitive photovoltaic cells from environmental influences such as hail, wind, and UV radiation. The treated glass components can, for example, be designed as bottles and / or food containers.

[0049] A system for carrying out the method according to the invention is particularly advantageous.

[0050] The system can advantageously be designed such that at least one line carrying liquid salt and / or at least one container holding liquid salt is thermally insulated. The insulation ensures uniform temperature conditions within the system, which increases process stability and leads to more consistent results. The thermal insulation also reduces the amount of heat lost from the system. By minimizing heat loss, the energy required to maintain the temperature is reduced. This lowers the energy costs for operating the system, as less additional energy is needed to keep the salt at the desired temperature. The insulation also protects adjacent system components from high temperatures. This prevents potential heat damage and extends the service life of the system components.

[0051] As already mentioned, the system can advantageously have a heat exchanger through which heat energy is extracted from the liquid salt.

[0052] A heat exchanger can, for example, be followed by an energy converter that transforms the extracted heat energy into another form of energy, particularly electrical energy. For instance, the energy converter could include a turbine that drives an electric generator.

[0053] The invention is shown in the drawing in an exemplary and schematic manner and is described below with reference to the figures, whereby identical or similarly functioning elements are usually provided with the same reference numerals even in different embodiments. Figure 10 shows:

[0054] Fig. 1 shows a first embodiment of a system according to the invention,

[0055] Fig. 2 shows a second embodiment of a system according to the invention,

[0056] Fig. 3 shows a third embodiment of a system according to the invention,

[0057] Fig. 4 shows a fourth embodiment of a system according to the invention,

[0058] Fig. 5 shows a fifth embodiment of a system according to the invention, and

[0059] Fig. 6 shows a sixth embodiment of a system according to the invention,

[0060] Figure 1 shows a first embodiment of a system 1 according to the invention. The system 1 is designed to receive glass objects 2 to be solidified and / or tempered from a glass production plant 3. Within the system 1, the glass objects 2 to be solidified and / or tempered are transported in a continuous flow to a basin 4 containing liquid salt 5.

[0061] The glass objects 2 are successively brought into contact with the liquid salt 5 by immersing them in the liquid salt 5. The glass objects 2 to be solidified and / or hardened are brought into contact with the liquid salt for a treatment period that is advantageously in the range of 5 minutes to 300 minutes, and particularly in the range of 15 minutes to 45 minutes. After the treatment period, the glass objects 2 are removed from the basin 4 and any adhering salt residues are removed in a cleaning device (not shown in Figure 1).

[0062] Basin 4 is connected to a heat exchanger 6 through which liquid salt 5 is continuously passed. Liquid salt 5 is continuously drawn from basin 4 and returned to basin 4 after passing through the heat exchanger 6.

[0063] In the heat exchanger 6, heat is transferred from the liquid salt 5 to another medium 7 (for example, water), which also flows through the heat exchanger 6. This causes the liquid salt 5 to cool down as it passes through the heat exchanger 6, since it releases heat to the other medium 7 in the heat exchanger 6.

[0064] The flowing medium 7 drives a turbine 8, which is connected to a heat exchanger 6. The turbine 8 can, for example, be a steam turbine. The mechanical 11

[0065] The energy of the turbine 8 is converted into electrical energy by means of a generator 9, which is connected downstream of the turbine 8 in terms of its drive system.

[0066] The electrical energy generated by generator 9 is transferred to the glass production plant 3. In this way, it is advantageously achieved that the glass production plant 3 has to draw less electrical energy from a public power grid 10.

[0067] Within the system, heat energy is continuously transferred exclusively from the glass 2 to be solidified and / or hardened to the liquid salt 5, whereby the liquid salt 5 always has a temperature above a predetermined or predeterminable minimum temperature.

[0068] The temperature of the liquid salt is regulated in a control loop of the system to a predetermined or predeterminable target temperature.

[0069] The control loop includes a temperature sensor 11, which is placed in the basin 4 containing the liquid salt 5. Alternatively, the temperature sensor 11 could, for example, be located in the supply line to the heat exchanger 6. The temperature sensor 11 measures the current temperature of the liquid salt 5 and transmits this information to an electronic controller 12. The controller processes the temperature signal from the temperature sensor 11 and compares the measured temperature with the setpoint temperature. Depending on the difference between the measured temperature and the setpoint temperature, the controller 12 controls a valve 13 in the secondary circuit of the heat exchanger 6, which contains the medium 7. Specifically, the controller 12 uses the valve 13 to control the amount of medium 7 that flows to the turbine 8 per unit of time.

[0070] In this embodiment, the amount of heat energy extracted from the liquid salt 5 per unit of time acts as a control variable of the control loop.

[0071] Figure 2 shows a second embodiment of a system 1 according to the invention. The system 1 is designed to receive glass objects 2 to be solidified and / or tempered from a glass production plant 3. Within the system 1, the glass objects 2 to be solidified and / or tempered are transported in a continuous flow to a basin 4 containing liquid salt 5.

[0072] The glass objects 2 are successively brought into contact with the liquid salt 5 by immersing them in the liquid salt 5. The glass objects 2 to be solidified and / or hardened are brought into contact with the liquid salt for a treatment period that is advantageously in the range of 5 minutes to 300 minutes, 12 particularly in the range of 15 minutes to 45 minutes. After the treatment period, the glass objects 2 are removed from the basin 4 and any adhering salt residues are removed in a cleaning device (not shown in Figure 2).

[0073] Basin 4 is connected to a heat exchanger 6 through which liquid salt 5 is continuously passed. Liquid salt 5 is continuously drawn from basin 4 and returned to basin 4 after passing through the heat exchanger 6.

[0074] In the heat exchanger 6, heat is transferred from the liquid salt 5 to another medium 7 (for example, water), which also flows through the heat exchanger 6. This causes the liquid salt 5 to cool down as it passes through the heat exchanger 6, since it releases heat to the other medium 7 in the heat exchanger 6.

[0075] The flowing medium 7 drives a turbine 8, which is connected to a heat exchanger 6. The turbine 8 can, for example, be a steam turbine. The mechanical energy of the turbine 8 is converted into electrical energy by means of a generator 9, which is connected downstream of the turbine 8.

[0076] The electrical energy generated by generator 9 is transferred to the glass production plant 3. In this way, it is advantageously achieved that the glass production plant 3 has to draw less electrical energy from a public power grid 10.

[0077] Within the system, heat energy is continuously transferred exclusively from the glass 2 to be solidified and / or hardened to the liquid salt 5, whereby the liquid salt 5 always has a temperature above a predetermined or predeterminable minimum temperature.

[0078] The temperature of the liquid salt is regulated in a control loop of the system to a predetermined or predeterminable target temperature.

[0079] The control loop includes a temperature sensor 11, which is placed in the basin 4 containing the liquid salt 5. Alternatively, the temperature sensor 11 could, for example, be located in the supply line to the heat exchanger 6. The temperature sensor 11 measures the current temperature of the liquid salt 5 and transmits this information to an electronic controller 12. The controller processes the temperature signal from the temperature sensor 11 and compares the measured temperature with the setpoint temperature. Depending on the difference between the measured temperature and the setpoint temperature, the controller 12 controls the transport speed of a transport device 14, which feeds the glass 2 to the liquid salt 5. In this 13

[0080] In this embodiment, the amount of glass 2 to be solidified and / or hardened that is brought into contact with the liquid salt per unit of time acts as a control variable of the control loop.

[0081] Figure 3 shows a third embodiment of a system 1 according to the invention.

[0082] The system 1 includes a heating device 15 in which the glass 2 to be solidified and / or hardened is heated to an initial temperature before it is brought into contact with the liquid salt.

[0083] Within the system 1, the glass objects 2 to be solidified and / or hardened are transported in a continuous stream to a basin 4 which contains liquid salt 5.

[0084] The glass objects 2 are successively brought into contact with the liquid salt 5 by immersing them in the liquid salt 5. The glass objects 2 to be solidified and / or hardened are brought into contact with the liquid salt for a treatment period that is advantageously in the range of 5 minutes to 300 minutes, and particularly in the range of 15 minutes to 45 minutes. After the treatment period, the glass objects 2 are removed from the basin 4 and any adhering salt residues are removed in a cleaning device (not shown in Figure 3).

[0085] The heating device 15 includes a preheating oven 16 and a main oven 17. The glass objects 2 to be solidified and / or tempered first pass through the preheating oven 16 in which they are preheated to a first temperature, and then through the main oven 17 in which they are heated from the first temperature to the final temperature.

[0086] The main furnace 17 is electrically powered and draws its electrical energy from a public power grid.

[0087] Basin 4 is connected to a heat exchanger 6 through which liquid salt 5 is continuously passed. Liquid salt 5 is continuously drawn from basin 4 and returned to basin 4 after passing through the heat exchanger 6.

[0088] In the heat exchanger 6, heat is transferred from the liquid salt 5 to another medium 7 (for example, water), which also flows through the heat exchanger 6. This causes the liquid salt 5 to cool down as it passes through the heat exchanger 6, since it is in the 14

[0089] Heat exchanger 6 transfers heat to the other medium 7.

[0090] The preheating furnace 16 is connected to the heat exchanger 6 and receives heat energy via the medium 7.

[0091] The temperature of the liquid salt is regulated in a control loop of the system to a predetermined or predeterminable target temperature.

[0092] The control loop includes a temperature sensor 11, which is placed in the basin 4 containing the liquid salt 5. Alternatively, the temperature sensor 11 could, for example, be located in the supply line to the heat exchanger 6. The temperature sensor 11 measures the current temperature of the liquid salt 5 and transmits this information to an electronic controller 12. The controller processes the temperature signal from the temperature sensor 11 and compares the measured temperature with the setpoint temperature. Depending on the difference between the measured temperature and the setpoint temperature, the controller 12 controls a valve 13 in the secondary circuit of the heat exchanger 6, which contains the medium 7. Specifically, the controller 12 uses the valve 13 to control the amount of medium 7 that flows to the preheating furnace 16 per unit of time.

[0093] In this embodiment, the amount of heat energy extracted from the liquid salt 5 per unit of time acts as a control variable of the control loop.

[0094] Figure 4 shows a fourth embodiment of a system 1 according to the invention.

[0095] The system 1 includes a heating device 15 in which the glass 2 to be solidified and / or hardened is heated to an initial temperature before it is brought into contact with the liquid salt.

[0096] Within the system 1, the glass objects 2 to be solidified and / or hardened are transported in a continuous stream to a basin 4 which contains liquid salt 5.

[0097] The glass objects 2 are successively brought into contact with the liquid salt 5 by immersing them in the liquid salt 5. The glass objects 2 to be solidified and / or hardened are brought into contact with the liquid salt for a treatment period that is advantageously in the range of 5 minutes to 300 minutes, and particularly in the range of 15 minutes to 45 minutes. After the treatment period, the glass objects 2 are removed from the basin 4 and any adhering salt residues are removed in a cleaning device (not shown in Figure 4).

[0098] The heating device 15 includes a preheating oven 16 and a main oven 17. The glass objects 2 to be solidified and / or tempered first pass through the preheating oven 16 in which they are preheated to a first temperature, and then through the main oven 17 in which they are heated from the first temperature to the final temperature.

[0099] The main furnace 17 is electrically powered and draws its electrical energy from a public power grid.

[0100] Basin 4 is connected to a heat exchanger 6 through which liquid salt 5 is continuously passed. Liquid salt 5 is continuously drawn from basin 4 and returned to basin 4 after passing through the heat exchanger 6.

[0101] In the heat exchanger 6, heat is transferred from the liquid salt 5 to another medium 7 (for example, water), which also flows through the heat exchanger 6. This causes the liquid salt 5 to cool down as it passes through the heat exchanger 6, since it releases heat to the other medium 7 in the heat exchanger 6.

[0102] The preheating furnace 16 is connected to the heat exchanger 6 and receives heat energy via the medium 7.

[0103] The temperature of the liquid salt is regulated in a control loop of the system to a predetermined or predeterminable target temperature.

[0104] The control loop includes a temperature sensor 11, which is placed in the basin 4 containing the liquid salt 5. Alternatively, the temperature sensor 11 could, for example, be located in the supply line to the heat exchanger 6. The temperature sensor 11 measures the current temperature of the liquid salt 5 and transmits this information to an electronic controller 12. The controller processes the temperature signal from the temperature sensor 11 and compares the measured temperature with the setpoint temperature. Depending on the difference between the measured temperature and the setpoint temperature, the controller 12 controls the temperature of the main furnace 17.

[0105] In this embodiment, the initial temperature of the glass objects 2 acts as a control variable of the control loop.

[0106] Figure 5 shows a fifth embodiment of a system 1 according to the invention. The system 1 is designed to separate glass objects 2 to be solidified and / or hardened from a 16

[0107] Glass production plant 3 is received. Within plant 1, the glass objects 2 to be solidified and / or hardened are transported in a continuous stream to a basin 4 containing liquid salt 5.

[0108] The glass objects 2 are successively brought into contact with the liquid salt 5 by immersing them in the liquid salt 5. The glass objects 2 to be solidified and / or hardened are kept in contact with the liquid salt for a treatment period that is advantageously in the range of 5 minutes to 300 minutes, and particularly in the range of 15 minutes to 45 minutes. After the treatment period, the glass objects 2 are removed from the basin 4 and any adhering salt residue is removed in a cleaning device (not shown in Figure 5).

[0109] Basin 4 is connected to a heat exchanger 6 through which liquid salt 5 is continuously passed. Liquid salt 5 is continuously drawn from basin 4 and returned to basin 4 after passing through the heat exchanger 6.

[0110] In the heat exchanger 6, heat is transferred from the liquid salt 5 to another medium 7 (for example, water), which also flows through the heat exchanger 6. This causes the liquid salt 5 to cool down as it passes through the heat exchanger 6, since it releases heat to the other medium 7 in the heat exchanger 6.

[0111] The flowing medium 7 drives a turbine 8, which is connected to a heat exchanger 6. The turbine 8 can, for example, be a steam turbine. The mechanical energy of the turbine 8 is converted into electrical energy by means of a generator 9, which is connected downstream of the turbine 8.

[0112] The electrical energy generated by generator 9 is transferred to the glass production plant 3. In this way, it is advantageously achieved that the glass production plant 3 has to draw less electrical energy from a public power grid 10.

[0113] Within the system, heat energy is continuously transferred exclusively from the glass 2 to be solidified and / or hardened to the liquid salt 5, whereby the liquid salt 5 always has a temperature above a predetermined or predeterminable minimum temperature.

[0114] The temperature of the liquid salt is regulated to a predetermined or predeterminable target temperature in a control loop of the system (not shown in detail in this figure). 02.09.2025

[0115] 084A0016W0

[0116] 17

[0117] The electrical energy generated by the generator 9 is directed to a control device 18 of a heating device 19. In this way, it is advantageously achieved that the heating device 19 has to draw less electrical energy from a public power grid to heat the glass objects 2 to the initial temperature.

[0118] Figure 6 shows a sixth embodiment, which is essentially constructed in the same way as the fifth embodiment. However, in addition, some of the electrical energy generated by the generator 9 is used to operate a cleaning device 20, which removes adhering salt 5 from the glass objects 2 that have been taken from the basin 4.

[0119] 18

[0120] List of reference symbols:

[0121] 1 Annex

[0122] 2 Glass / glass objects

[0123] 3 Glass production plant

[0124] 4 pools

[0125] 5 liquid salt

[0126] 6 heat exchangers

[0127] 7 Medium

[0128] 8 Turbine

[0129] 9 Generator

[0130] 10 public electricity grid

[0131] 1 1 Temperature sensor

[0132] 12 regulators

[0133] 13 valve

[0134] 14 Transport device

[0135] 15 Heating device

[0136] 16 Preheating oven

[0137] 17 Main furnace

[0138] 18 Control device

[0139] 19 Heating device

[0140] 20 Cleaning device

Claims

19 Patent claims 1. A method for strengthening and / or hardening glass, in which glass objects (2) are continuously brought into contact with a liquid salt (5), characterized in that heat energy is transferred to the liquid salt (5) exclusively from the glass (2) to be strengthened and / or hardened.

2. Method according to claim 1, characterized in that the temperature of the liquid salt is regulated in a control loop to a predetermined or predeterminable target temperature.

3. Method according to claim 2, characterized in that the target temperature is in a range of 50 Kelvin to 200 Kelvin below the transformation temperature of the glass material.

4. Method according to one of claims 1 to 3, characterized in that the glass (2) to be solidified and / or hardened is brought into contact with the liquid salt (5) in a continuous flow.

5. Method according to one of claims 1 to 5, characterized in that the glass (2) to be solidified and / or hardened is brought into contact with the liquid salt (5) for a treatment period in the range of 5 minutes to 300 minutes, in particular in the range of 15 minutes to 45 minutes.

6. Method according to one of claims 2 to 5, characterized in that the amount of glass (2) to be solidified and / or hardened, which is brought into contact with the liquid salt (5) per unit of time, acts as a control variable of the control loop.

7. Method according to one of claims 1 to 6, characterized in that the amount of heat energy extracted per unit of time from the liquid salt (5) acts as a control variable of the control loop.

8. Method according to one of claims 1 to 7 or according to the preamble of claim 1, characterized in that heat energy is extracted from the liquid salt (5), in particular by means of a heat exchanger.

9. Method according to claim 8, characterized in that the extracted heat energy is used to produce further glass (2) to be solidified and / or tempered and / or glass objects.

10. Method according to claim 8 or 9, characterized in that the extracted heat energy is used to heat already produced glass (2) to be solidified and / or tempered. 20 1. Method according to one of claims 8 to 10, characterized in that the extracted heat energy is converted into another form of energy, in particular into electrical energy.

12. Method according to one of claims 1 to 1 1 , characterized in that the glass (2) to be solidified and / or hardened is heated to an initial temperature and then brought into contact with the liquid salt (5).

13. Method according to claim 12, characterized in that the output temperature functions as a control variable of the control loop.

14. Method according to claim 12 or 13, characterized in that a. the initial temperature is in a range of 100 Kelvin to 200 Kelvin above the transformation temperature of the glass, and / or that b. the initial temperature is in a range of 50 Kelvin below and 30 Kelvin above the Littleton point of the glass material.

15. Method according to claim 13 or 14, characterized in that the heating is carried out by irradiating the glass (2) with microwaves.

16. Method according to one of claims 13 to 15, characterized in that the heating is carried out using an oven.

17. Method according to one of claims 2 to 16, characterized in that the target temperature is at least 200 Kelvin and at most 450 Kelvin, in particular at least 200 Kelvin and at most 350 Kelvin, below the initial temperature.

18. Method according to one of claims 2 to 17, characterized in that the glass (2) to be consolidated and / or tempered consists of glass containers or flat glass parts.

19. Apparatus for carrying out a method according to any one of claims 1 to 18.

20. Plant for solidifying and / or hardening glass, in which the glass articles (2) are brought into contact with a liquid salt (5), characterized in that the plant is designed in such a way that heat energy to the liquid salt (5) is transferred exclusively from the glass (2) to be solidified and / or hardened.

21. System according to claim 19 or 20, characterized in that the system has a control loop in which the temperature of the liquid salt (5) is regulated to a predetermined or predeterminable target temperature. 21 22. System according to claim 21, characterized in that the target temperature is in a range of 50 Kelvin to 200 Kelvin below the transformation temperature of the glass material.

23. Plant according to one of claims 19 to 22, characterized in that at least one line carrying liquid salt (5) and / or at least one container containing liquid salt (5) of the plant are thermally insulated.

24. Plant according to one of claims 19 to 23, characterized in that the plant has a transport device (14) which transports the glass (2) to be solidified and / or hardened in a continuous flow to the liquid salt (5).

25. System according to one of claims 19 to 24, characterized in that the system brings the glass (2) to be solidified and / or hardened into contact with the liquid salt (5) for a treatment period which is in the range of 5 minutes to 300 minutes, in particular in the range of 15 minutes to 45 minutes.

26. System according to one of claims 20 to 25, characterized in that the amount of glass (2) to be solidified and / or hardened, which is brought into contact with the liquid salt (5) per unit of time, acts as a control variable of the control loop.

27. System according to one of claims 20 to 26, characterized in that the amount of heat energy extracted per unit of time from the liquid salt (5) acts as a control variable of the control loop.

28. System according to one of claims 19 to 27 or according to the preamble of claim 20, characterized in that the system has a heat exchanger (6) through which heat energy is extracted from the liquid salt (5).

29. System according to claim 28, characterized in that an energy converter is connected downstream of the heat exchanger (6) in terms of drive technology, which converts the extracted heat energy into another form of energy, in particular into electrical energy.

30. System according to claim 29, characterized in that the energy converter has a turbine (8).

31. System according to claim 29 or 30, characterized in that the energy converter has an electric generator (9).

32. System according to one of claims 19 to 31, characterized in that the system has a heating device (15, 19) in which glass (2) to be solidified and / or hardened is heated to an initial temperature before it is brought into contact with the liquid salt (5). 22 33. System according to claim 32, characterized in that the output temperature functions as a control variable of the control loop.

34. System according to claim 32 or 33, characterized in that the heating device (15, 19) receives at least a part of the heat energy extracted from the liquid salt (5) directly or indirectly.

35. System according to one of claims 32 to 34, characterized in that the heating device (15, 19) heats the glass (2) to be solidified and / or hardened to an initial temperature.

36. System according to claim 35, characterized in that a. the initial temperature is in a range of 100 Kelvin to 200 Kelvin above the transformation temperature of the glass, and / or that b. the initial temperature is in a range of 50 Kelvin below and 30 Kelvin above the Littleton point of the glass material.

37. System according to one of claims 32 to 36, characterized in that the heating device (15, 19) has a microwave generator.

38. System according to one of claims 32 to 37, characterized in that the heating device (15, 19) comprises an oven.

39. System according to one of claims 21 to 38, characterized in that the setpoint temperature is at least 200 Kelvin and at most 450 Kelvin, in particular at least 200 Kelvin and at most 350 Kelvin, below the output temperature.

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