Glass or glass-ceramic article and plant for its manufacture

Abstract

Strength-enhanced glass or glass-ceramic article manufactured by the following steps: a) Providing an article made of glass or glass ceramic (glass or glass ceramic article) with a temperature in the range from 300°C to 750°C, preferably 350°C to 500°C, but in any case below a softening point (Littleton point) of the glass or glass ceramic, in particular by means of a heating cascade which comprises a number of, in particular 2 to 30, preferably 3 to 20, and particularly preferably 4 to 15, respective discrete receiving spaces, preferably each heated to a certain predetermined elevated temperature, wherein the respective next receiving space has a higher temperature than the respective preceding receiving space; b) providing a molten salt or salt solution containing exchange ions; c) subsequently applying the molten salt or salt solution to at least a first region of the glass or glass-ceramic article; d) subsequent heating, in particular superheating, of the surface of the glass or glass-ceramic article in the first region of the applied salt melt or salt solution for a period of time in the range from 1 s to 5 min, preferably 3 s to 40 s and particularly preferably 4 s to 20 s, to a temperature close to the softening point, in particular to a temperature of 20°C to 200°C, preferably 30°C to 150°C and particularly preferably 50°C to 100°C above a softening point (Littleton point) of the glass and / or the glass or glass-ceramic article; e) subsequent dry removal of salt present on the surface of the glass or glass-ceramic article, preferably by blowing with warm gas, preferably with air having a temperature in the range from 200°C to 500°C, preferably at 230°C to 400°C and particularly preferably at 250°C to 350°C; f) subsequent cooling of the glass or glass-ceramic article over a period of time in the range from 3 minutes to 30 minutes, preferably from 4 minutes to 20 minutes and particularly preferably from 5 minutes to 10 minutes to a temperature below 300°C, preferably below 200°C and particularly preferably below 150°C, in particular to a temperature between room temperature and 90°C±5K, in particular by means of a cooling cascade which comprises a number of, in particular 2 to 30, preferably 3 to 20, and particularly preferably 4 to 15, respective discrete receiving spaces, each preferably heated to a certain predetermined elevated temperature, wherein the respective next receiving space has a lower temperature than the respective preceding receiving space.

Description

[0001] The invention relates to a strength-enhanced glass or glass-ceramic article according to the preamble of claim 1 and to a plant for its production according to the preamble of claim 15.

[0002] It is known from the prior art that the mechanical strength of glass and / or glass-ceramic objects can be improved by subjecting them to a strength-enhancing process. For this purpose, the prior art uses an ion exchange process for the glass or glass-ceramic objects or products to be strengthened, which is sometimes also referred to as chemical hardening. In such an ion exchange process, small alkali ions of the glass or glass-ceramic, usually sodium ions and sometimes lithium ions, which are located close to the surface of the product to be strengthened and thus usually also hardened, are replaced by larger ions, usually potassium ions. This process is also referred to as "crowding" or "ion stuffing."The exchange of ions occurs at the same points in the glass network of the glass and / or glass-ceramic article without significantly changing the silicon-oxygen bonds of the original network structure. Furthermore, the exchange takes place at temperatures below the glass transition temperature Tg of the glass of a particular glass and / or glass-ceramic article. This is a thermally activated interdiffusion process. The ion exchange near the surface of the glass and / or glass-ceramic article creates compressive stress, which leads to strengthening of the glass and / or glass-ceramic article. As with thermal tempering of glass products, strengthening occurs through the buildup of residual compressive stress in the glass down to a certain depth below the surface of the glass and / or glass-ceramic article.This residual compressive stress in the glass is balanced by a tensile stress state in the inner layers of the product. This type of chemical hardening, or tempering, of the glass can increase the impact strength, fracture strength, scratch resistance, flexural strength, and thermal shock resistance of the respective glass and / or glass-ceramic article.

[0003] According to the state of the art, chemical hardening is typically achieved by immersing the glass and / or glass-ceramic article in a molten alkali salt. During the immersion, the alkali ions of the glass or glass-ceramic are exchanged for the larger alkali ions of the molten salt.

[0004] Furthermore, it is known from the prior art that an ion exchange of alkali ions by, for example, silver and / or copper ions can not only strengthen a glass object but also produce a coloration near the surface of the glass object.

[0005] For example, US Pat. No. 3,615,322 A describes a combination of an ion exchange process for glass articles with a flame treatment. After the forming process, soda-lime glasses are exposed to copper chloride vapor for, say, two hours to undergo ion exchange with the sodium ions in the glass. This results in the formation of sodium chloride on the surface of the glass article, which is washed off with water after the glass article has cooled. After the glass article is reheated, it is fire polished, which can significantly increase the strength of the glass article. As an alternative to copper chloride, the use of copper iodide or copper sulfate is suggested.The use of copper iodide is particularly advantageous because the sodium iodide formed during ion exchange has such a high vapor pressure that fire polishing can be carried out directly after the ion exchange, during which the sodium iodide salt residues evaporate.

[0006] From WO 2022 / 049 206 A1, it is known that, prior to ion exchange, glass products are briefly preheated in a furnace to temperatures up to 50 Kelvin above the softening point of the respective glass article. They are then immersed in a significantly colder salt bath serving as a cooling agent, or sprayed or sprinkled with a salt mist serving as a cooling agent. To prevent deformation of the glass products, the minimum wall thickness limits the duration of the heat treatment.

[0007] Previously known methods for improving the strength of glass and / or glass-ceramic objects through an ion exchange process have numerous disadvantages. A significant disadvantage of known methods is that neither the temperature nor the duration of the actual exposure time can be specifically controlled in the contact zone between the medium containing the exchange ions and the glass and / or glass-ceramic object. This is because immersing a glass and / or glass-ceramic object in a molten alkali salt either requires the glass and / or glass-ceramic object to first be cooled to the temperature of the molten alkali salt, as described, for example, in WO 2022 / 049 206 A1, or to first be heated to the temperature of the molten alkali salt in order for an ion exchange process to even begin.The same disadvantage also occurs, for example, if, instead of an immersion bath, a heated glass and / or glass-ceramic object is sprayed or sprinkled with a molten salt or a salt solution containing the exchange ions, since in this case, too, the glass and / or glass-ceramic object cools down, which in any case leads to poor controllability of the actual ion exchange process and a generally very long contact time, sometimes lasting several hours, between the glass and / or glass-ceramic object and the ion exchange salt.

[0008] Another significant disadvantage of previous methods for improving the strength of glass and / or glass-ceramic objects is that a large amount of washing water is required to remove salt residues when cleaning the glass and / or glass-ceramic objects, which in turn leads to a very large amount of brine, which in turn has to be disposed of or treated at great expense.

[0009] When using copper iodide vapor for ion exchange, as described, for example, in US Pat. No. 3,615,322, the disadvantage of a very long reaction time of several hours coincides with the difficulty of not only completely extracting the aggressive copper iodide vapor but also disposing of it properly. Furthermore, using copper iodide for ion exchange is not only expensive but also leads to surface discoloration of the glass object.

[0010] Another significant disadvantage of existing ion exchange processes for strengthening glass and glass objects is that it has not been possible to treat glass objects only on one side, e.g. to subject bottles or other containers or even pipes, for example, to an ion exchange process only on their outside, while the side of a respective glass surface opposite the treated side remained untreated.

[0011] The object of the invention is to offer a glass or glass-ceramic article with increased strength, while avoiding the above-mentioned problems, which is produced using a process which, compared to the previously known prior art, is easily controllable with regard to a contact time between the ion exchange medium and the glass or glass-ceramic article and a contact temperature at a contact surface between the ion exchange medium and the glass or glass-ceramic article, and which is suitable for glass or glass-ceramic articles with wall thicknesses of less than 2 mm. As well as an improved cleaning of the glass or glass-ceramic article compared to the previous prior art for freeing the glass or glass-ceramic article of ion exchange medium, in particular salt. Furthermore, the object of the invention is to provide a system for the efficient production of the glass or glass-ceramic article.

[0012] This object is achieved by a strength-enhanced glass or glass-ceramic article according to claim 1 and by a system according to claim 15.

[0013] In particular, the problem is solved by a strength-enhanced article made of glass or glass ceramic, i.e. a glass or glass ceramic article, which is manufactured by the following steps: a) Providing an article made of glass or glass ceramic, ie a glass or glass ceramic article with a temperature in the range from 300°C to 750°C, preferably 350°C to 500°C, but in any case below a softening point (Littleton point) of the glass or glass ceramic, in particular by means of a heating cascade which comprises a number of, in particular 2 to 30, preferably 3 to 20, and particularly preferably 4 to 15, respective discrete receiving spaces, each preferably heated to a certain predetermined elevated temperature, wherein the next receiving space in each case has a higher temperature than the previous receiving space in each case; b) providing a molten salt or salt solution containing exchange ions; c) subsequently applying the molten salt or, where appropriate, salt solution to at least a first region of the glass or glass-ceramic article; d) subsequent heating, in particular superheating, of the surface of the glass or glass-ceramic article in the first region of the applied salt melt for a period of time in the range from 1 s to 5 min, preferably 3 s to 40 s and particularly preferably 4 s to 20 s, to a temperature close to the softening point, in particular to a temperature of 20°C to 200°C, preferably 30°C to 150°C and particularly preferably 50°C to 100°C above a softening point (Littleton point) of the glass and / or the glass or glass-ceramic article; e) subsequent dry removal of salt present on the surface of the glass or glass-ceramic article, preferably by blowing with warm gas, preferably with air at a temperature in the range of 200°C to 500°C, preferably at 230°C to 400°C and particularly preferably at 250°C to 350°C; and f) subsequent cooling of the glass or glass-ceramic article over a period of time in the range from 3 minutes to 30 minutes, preferably from 4 minutes to 20 minutes and particularly preferably from 5 minutes to 10 minutes to a temperature below 300°C, preferably below 200°C and particularly preferably below 150°C, in particular to a temperature between room temperature and 90°C±5K, in particular by means of a cooling cascade which comprises a number of, in particular 2 to 30, preferably 3 to 20, and particularly preferably 4 to 15, respective discrete receiving spaces, each preferably heated to a certain predetermined elevated temperature, wherein the respective next receiving space has a lower temperature than the respective preceding receiving space.

[0014] A key aspect of the invention is that a glass or glass-ceramic article is provided at a temperature in the range of 300°C to 750°C, preferably 350°C to 500°C, i.e., at a temperature that has the same temperature range as the molten salt containing the exchange ions. By providing a glass and / or glass-ceramic article preheated to such a temperature, a direct application of a molten salt in the same temperature range is possible without thermal stresses occurring in the glass and / or glass-ceramic article.

[0015] Another important point is that although the glass or glass-ceramic article is heated to an elevated temperature, this elevated temperature remains below a softening point of the treated glass or glass-ceramic, also known as the Littleton point, so that the geometry and structure of the glass or glass-ceramic article are retained. Heating the glass or glass-ceramic article to an elevated temperature below the softening point serves to thermally precondition the glass or glass-ceramic article and thus avoid thermal shock, but not to carry out ion exchange, which, as is known from the prior art, does occur at this temperature, but not at a significant rate that would be useful for producing the glass or glass-ceramic article according to the invention.

[0016] In this context, it should also be noted that the terms object made of glass or glass-ceramic and glass or glass-ceramic object are used synonymously in this patent application.

[0017] Due to the fact that the molten salt is essentially at the same temperature as the glass or glass-ceramic object, the molten salt can be applied particularly well to the surface of the glass or glass-ceramic object to be treated and, if desired or necessary, can be distributed in a targeted manner, perhaps in a pattern, or for example along a seam. This is possible because the consistency of the molten salt is essentially retained when applied to the surface of the glass or glass-ceramic object to be treated, i.e. it remains spreadable or flowable, for example, and does not solidify on the surface of the glass or glass-ceramic object due to sudden cooling or, in the opposite case, liquefied and possibly dripping on the surface of the glass or glass-ceramic object due to sudden heating.

[0018] An important point here is that for preheating the glass and / or glass-ceramic object to be treated, both the heat available from the shaping of the glass and / or glass-ceramic object and the heat emitted by the container of the molten salt or the molten salt itself can be advantageously used. Thus, according to the invention, it is possible to subject a just-manufactured glass and / or glass-ceramic object to an inventive increase in its strength. A further advantage is that it is possible to utilize the process heat available from the provision of molten salt to temper the glass and / or glass-ceramic object to be treated to an optimal temperature.This can be achieved, for example, by placing the glass and / or glass-ceramic object to be treated on the rim or rim of the container containing the molten salt when use of the molten salt is not required during one or more process steps. In such a case, the top of the container containing the molten salt can be closed with a lid. In this case, the lid not only counteracts heat loss from the molten salt, but its top can also be used as a base for glass and / or glass-ceramic objects to be treated subsequently. The glass and / or glass-ceramic object to be treated can thus be placed in a waiting position on the lid or rim of the container containing the molten salt and, in the time elapsed until its further treatment, can reach the temperature required for its further treatment.

[0019] According to a particularly preferred embodiment of the invention, the heating of the glass or glass-ceramic article is carried out by means of a heating cascade which comprises a number of, in particular 2 to 30, preferably 3 to 20, and particularly preferably 4 to 15, respectively discretely arranged receiving spaces, preferably each tempered to a certain predetermined elevated temperature, wherein the respective next receiving space of the heating cascade has a higher temperature than the respective preceding receiving space of the heating cascade.

[0020] In terms of plant technology, the heating cascade consists of a number of receiving spaces, which are designed, for example, as containers that are open at the top and preferably have insulating side walls, and which are kept at an essentially constant temperature inside.

[0021] Within the heating cascade, the individual receiving spaces, or containers, are arranged so that the coolest container is located at the beginning of the heating cascade, and each subsequent container within the heating cascade has a higher temperature than the preceding container. The temperature steps between the individual containers can be freely selected; in the case of small temperature steps between the individual successive containers, the heating cascade comprises correspondingly more containers, or receiving spaces.

[0022] Typically, the respective temperature steps, i.e., temperature differences between the individual containers, are in the range from 50K to 200K, whereby the temperature steps between the individual receiving spaces can be identical or different. Within the scope of the invention, it has been shown that it can be expedient to select the temperature steps from one receiving space of the heating cascade to the respective subsequent receiving space of the heating cascade to be rather larger in a lower temperature range up to approximately 400°C to 500°C, i.e., in the range from 100K to 200K, and to be rather smaller in a temperature range beyond this, i.e., in the range from 50K to 100K.

[0023] According to the process, the glass and / or glass-ceramic objects to be treated are first placed in a first receiving chamber of the heating cascade for heating, where the glass and / or glass-ceramic objects reach the temperature set in this first receiving chamber of the heating cascade. For this purpose, the glass and / or glass-ceramic objects are placed in the receiving chamber and left there for a certain period of time, which, depending on the shape and size of the glass and / or glass-ceramic object to be treated, can range from a few seconds to a few minutes.

[0024] As soon as the glass and / or glass-ceramic object to be treated has essentially reached the temperature of this first receiving chamber of the heating cascade, the glass and / or glass-ceramic object to be treated is transferred to the next receiving chamber of the heating cascade, which has a higher temperature than the previous receiving chamber of the heating cascade. Analogous to the previous container of the heating cascade, the glass and / or glass-ceramic object to be treated is left in this second receiving chamber of the heating cascade until the glass and / or glass-ceramic object has again reached the temperature of this second receiving chamber of the heating cascade.The glass and / or glass-ceramic object to be treated is then transferred to the next receiving chamber, which is again heated to a higher temperature inside the container. It is left there until the desired temperature is reached, and then transferred to the next receiving chamber, again at a higher temperature. This procedure is repeated until the glass and / or glass-ceramic object to be treated has reached the elevated temperature required for the subsequent process.

[0025] According to the invention, each receiving chamber or container of the heating cascade is operated in such a way that the heat transfer to the glass and / or glass-ceramic object introduced into the receiving chamber is as optimal as possible. For this purpose, if the initial temperature of the glass and / or glass-ceramic object to be treated is, for example, in the range of room temperature ± 20°C, or generally below approximately 80°C, water with a temperature close to, but below, the boiling point of water is preferably used in a first receiving chamber.

[0026] At higher temperatures, i.e. temperatures above the boiling point of water, each receiving chamber of the heating cascade can contain a different medium that ensures good temperature transfer to the glass and / or glass-ceramic object, such as liquid tin or an inert gas. The respective receiving chamber can be heated in a conventional way, for example electrically, by induction or by means of infrared radiators. If gas is used, such as air, the heating of the gas or the air can also take place outside the actual receiving chamber of the heating cascade. The gas or the air heated to the desired temperature can then be introduced into the receiving chamber, for example by blowing it in.

[0027] According to a further preferred embodiment of the invention, the glass and / or glass-ceramic object to be treated is thermally insulated from the environment during each transfer from one receiving space to the next receiving space of the heating cascade. According to the invention, this is preferably achieved by the glass and / or glass-ceramic object, which according to the invention is preferably conveyed from above into a respective receiving space and upwards out of the respective receiving space, being placed essentially directly and without delay into a sleeve with temperature-insulation on its side walls during the course of the glass and / or glass-ceramic object being conveyed out of the respective container.

[0028] In order to move the glass and / or glass ceramic object to be treated into the next receiving chamber, the glass and / or glass ceramic object is removed from its respective sleeve and simultaneously moved into the desired receiving chamber.

[0029] According to the invention, such a sleeve is either uniformly shaped, ie circular or oval, or is adapted with regard to its outer contour to the glass and / or glass-ceramic article to be treated.

[0030] The glass and / or glass ceramic object to be treated is held by a holding device according to the invention.

[0031] The sleeve, which is designed to be open in a respective direction of movement of the glass and / or glass-ceramic object into the sleeve or out of the sleeve, at least at the end at which the glass and / or glass-ceramic object is moved into or out of the sleeve, can be completely or partially closed at its opposite end for better temperature insulation, wherein the holding device can engage in the sleeve in such a way that the glass / or glass-ceramic object can be moved out of the sleeve and back by means of the holding device, for example in a telescopic manner.

[0032] According to a further advantageous embodiment of the invention, the sleeve can also be designed as an inverted spring basket, i.e. with an opening facing downwards, wherein the spring basket can be composed of retractable segments or partial sleeves or spring elements which do not require the glass and / or glass ceramic object to be treated to be moved out of the sleeve when the glass and / or glass ceramic object is to be moved into a respective receiving space of the heating cascade, but that the spring basket is retracted, releasing the glass and / or glass ceramic object, to such an extent that the glass and / or glass ceramic object to be treated, held on the holding device and with the sleeve or spring basket retracted, dips into the receiving space of the heating cascade and assumes the desired temperature there.

[0033] In this context, it should be noted that the sleeve can, if desired, accommodate, i.e. enclose, one or more glass and / or glass-ceramic objects to be treated, for example when not only one glass and / or glass-ceramic object is to be treated individually, but a large number of glass and / or glass-ceramic objects are to be treated simultaneously.

[0034] If a large number of glass and / or glass-ceramic objects are to be treated in parallel and synchronously, ie essentially at the same time, these glass and / or glass-ceramic objects can be held either individually and separately by a holding device or by a common holding device.

[0035] According to a further advantageous embodiment of the invention, the sleeve can be insulated purely passively, for example by a double wall, or alternatively or additionally provided with a heater to ensure that the temperature of the glass and / or glass-ceramic article, which is surrounded by the sleeve during a transfer from one receiving space of the heating cascade to a next receiving space of the heating cascade, is maintained as precisely and constantly as possible.

[0036] A significant advantage of the sleeve according to the invention is that the glass and / or glass-ceramic article located within the sleeve, i.e., surrounded by the sleeve, is protected from external environmental influences that may not be controllable. A further additional advantage of the sleeve according to the invention is that the glass and / or glass-ceramic article located within the sleeve, i.e., surrounded by the sleeve, is also protected from mechanical influences.

[0037] A further essential point of the invention is that the salt melt applied to the glass or glass-ceramic article is subsequently heated together with the surface of the glass or glass-ceramic article to which the salt melt is applied, to a temperature close to the softening point, in particular to a temperature of 20°C to 200°C, preferably 30°C to 150°C and particularly preferably 50°C to 100°C above a softening point (= Littleton point) of the glass and / or the glass or glass-ceramic article.

[0038] According to the invention, this heating takes place very quickly, ie in a booster-like manner, for a period of 1 second to a maximum of 5 minutes, but preferably significantly shorter, ie for a period of 3 seconds to 40 seconds and particularly preferably only for a period of 4 seconds to 20 seconds.

[0039] The essential advantage associated with this is that, according to the invention, neither the molten salt cools the surface of the glass or glass-ceramic article to be treated nor vice versa, but that due to the very rapid heating of the entire contact zone of glass and molten salt, a softening of both glass and salt occurs, which leads to a massive increase in the speed of ion exchange between glass and salt, whereby a penetration depth of exchange ions from the salt into the glass is increased and can be specifically controlled by varying both the time and the heating or superheating temperature.

[0040] This means that it is possible according to the invention to precisely influence the diffusion rate of ions by precisely adjusting the temperature over time and space, and in this way to subject a glass or glass-ceramic object to a stronger ion exchange process in certain areas and to a lower ion exchange process in other areas.

[0041] The terms stronger ion exchange process and lower ion exchange process refer to a deeper or lower penetration depth of the exchange ions into the glass to be treated as well as to an exchange ion density to be achieved in the treated glass and the speed of the ion exchange process.

[0042] In this way, it is possible according to the invention, for example, to subject a bottle whose wall thickness varies from the neck down to its base to an ion exchange process in a differentiated manner across its height and according to respective wishes or needs. The neck or the base of the bottle can, for example, remain untreated, while a lateral area above the base is subjected to an ion exchange process that is strong, for example, in terms of penetration depth and ion exchange density, and thus to a significant increase in strength. In this way, for example, a base with grooves can remain untreated to prevent unwanted smoothing of the grooves, while a slightly bulbous side wall of the bottle, which, in a combination with other bottles, rests against these other bottles and is subject to possible impact and friction loads, can be subjected to a significant increase in strength.

[0043] Another important aspect of the process is that salt is removed from the treated surface of the glass or glass-ceramic article after performing an ion exchange process, not by a washing process, but by means of a dry cleaning process. According to the invention, this dry cleaning process is preferably carried out by blowing off excess salt remaining on the surface of the glass or glass-ceramic article, preferably using a warm or hot air blower.

[0044] Such a dry cleaning process for removing residual salt from the surface of the treated glass or glass-ceramic article, which is used according to the invention, offers numerous advantages. For example, the salt blown off the surface of the treated glass or glass-ceramic article by a blower can be easily collected and fed into a disposal container or returned to the molten salt bath. Due to the relatively low proportion of returned salt, the composition of the molten salt bath does not change significantly when the blown-off salt is returned to the molten salt bath. This can be monitored.A further significant advantage of the dry cleaning method used according to the invention is that, unlike in a washing process, before cleaning the surface of the glass or glass-ceramic object, it is not necessary to wait until the glass or glass-ceramic object has cooled down in order to avoid any temperature-related stresses and the associated damage and possibly fractures in a matrix of the glass or glass-ceramic object, but rather the cleaning of the surface of the glass or glass-ceramic object can begin immediately after completion of the ion exchange process, i.e. immediately after switching off the heating device required for heating and overheating the surface of the glass or glass-ceramic object, for example the burner.With the invention, any temperature-related stresses are not to be feared, as the hot air used can be precisely adjusted to the temperature of the glass or glass-ceramic object being treated. Furthermore, the hot air temperature can be deliberately lowered during the cleaning process to simultaneously cool the still-hot glass or glass-ceramic object, thereby increasing the cycle rate of the process and reducing the subsequent cooling time.

[0045] According to a further preferred embodiment of the invention, the subsequent cooling of the glass or glass-ceramic article to a temperature below 300°C, preferably below 200°C and particularly preferably below 150°C, in particular to a temperature between room temperature and 90°C±5K, is preferably carried out by means of a cooling cascade which comprises a number of, in particular 2 to 30, preferably 3 to 20, and particularly preferably 4 to 15, respective discrete receiving spaces, each preferably heated to a certain predetermined elevated temperature, wherein the respective next receiving space has a lower temperature than the respective preceding receiving space.

[0046] According to the invention, this cooling cascade is constructed essentially inversely to the heating cascade and functions accordingly. The cooling cascade also has a number of receiving spaces, which can be designed as open-topped containers, into which the glass and / or glass-ceramic object to be treated is placed and, after its temperature has adjusted to the temperature within the receiving space of the cascade, is removed again, for example, by moving it. After the glass and / or glass-ceramic object to be treated has reached the desired temperature in the respective container of the cooling cascade, the glass and / or glass-ceramic object is transferred, if desired again using a sleeve constructed analogously to the heating cascade, to the next cooler container of the cooling cascade and left there again until its temperature has adjusted. The time periodthe respective glass and / or glass-ceramic object or, in the case of simultaneous treatment of several glass and / or glass-ceramic objects, the plurality of these glass and / or glass-ceramic objects is left in containers of the cooling cascade, is in accordance with the invention in each case approximately within the same time window as a corresponding heating step in the heating cascade in the same temperature range, so that glass and / or glass-ceramic objects to be treated can be subjected to a continuous process in which a further glass and / or glass-ceramic object is handled immediately after a first glass and / or glass-ceramic object, and then another, and then another, respectively, next glass and / or glass-ceramic object, since the respective process steps for heating the glass and / or glass-ceramic object run "backward synchronously" with the respective process steps for cooling the glass and / or glass-ceramic object.

[0047] According to one embodiment of the invention, the temperature steps during the cooling of the treated glass and / or glass-ceramic article and the number of receiving spaces or containers in the cooling cascade essentially correspond to the temperature steps during the heating in reverse order and the number of receiving spaces or containers in the heating cascade.

[0048] At this point, it should be noted that the use of such a heating cascade and cooling cascade according to the invention as described above offers numerous advantages over previous methods in which an object to be treated passes through various temperature zones on a conveyor belt during heating and / or cooling. These advantages include, among other things, a significantly more homogeneous process and temperature control, and are also due to the fact that the glass and / or glass-ceramic object to be treated is not exposed to any unwanted and even detrimental convection. Correct temperature maintenance is possible with significantly greater precision using the heating cascade and cooling cascade according to the invention, and, when using a sleeve, also using the sleeve itself. This has an extremely positive effect on the speed, duration, and thus precision of the ion exchange following the heating phase.

[0049] According to one embodiment of the invention, the preheated glass or glass ceramic article is coated in step c), ie for applying the molten salt to at least a first region of the glass or glass ceramic article, by dipping into a molten salt, ie a so-called dip coating, wherein an immersion time is between 5 s and 24 hrs, preferably between 5 s and 30 min and particularly preferably between 5 s and 15 min.

[0050] Alternatively and / or additionally, the preheated glass or glass-ceramic article can be coated according to the invention by spraying with a molten salt or salt solution.

[0051] Immersion in a molten salt solution is particularly preferred according to the invention, since immersing a glass or glass-ceramic object in a molten salt solution or salt solution, for example, held at its upper end by a gripper, is particularly easy to perform and results in a very homogeneous coating of the glass or glass-ceramic object to be treated. Furthermore, when immersing a glass or glass-ceramic object in a molten salt solution, there is no need to worry about contamination of the surrounding area, as might be the case when spraying the glass or glass-ceramic object due to salt medium bouncing off or being deflected from the surface of the glass or glass-ceramic object.When a glass or glass-ceramic object is immersed in a molten salt or salt solution and then removed from the molten salt or salt solution, the most that can happen is that some molten salt or salt solution drips from the glass or glass-ceramic object, whereby this molten salt or salt solution would then simply drip back into the molten salt or salt solution without leaving any contamination.

[0052] At this point, it should be explicitly noted that a full-surface coating of the glass or glass-ceramic object to be treated does not automatically mean that the glass or glass-ceramic object is treated over its entire surface during an ion exchange process. Rather, a very important aspect of the invention is that the method allows for the application of heat, in particular superheating, to specific areas of such a fully coated glass or glass-ceramic object in such a way that an ion exchange process is initiated on a significant scale within the process time.In this case, a significant degree of ion exchange refers to a degree of ion exchange that actually leads to strengthening of the glass or glass-ceramic article; a simple ion exchange that occurs purely through glass / salt contact without additional heating, in particular overheating, of the glass / salt contact zone by simple diffusion is not considered an ion exchange process within the scope of this invention.

[0053] Furthermore, it should be noted that, as mentioned above, the application of a molten salt or salt solution to the preheated glass or glass-ceramic object to be treated is also possible by spraying. This can be advantageous, for example, if a specific area, such as a single seam in the glass or glass-ceramic object, is to be treated. In such a case, the molten salt or salt solution would be applied according to the invention only to the area of ​​the glass or glass-ceramic object actually to be treated, which would advantageously reduce, for example, the amount of molten salt or salt solution required.

[0054] It should be noted here that, for the purposes of this invention, the term "salt solution" refers to an aqueous salt solution. The water content of the salt solution is extremely low and evaporates immediately during the application process, leaving only the salt containing the exchange ions on the glass or glass-ceramic object to be treated.

[0055] According to the invention, the exchange ions are potassium ions and a salt used for the ion exchange is a potassium salt, preferably potassium nitrate, wherein according to a preferred embodiment of the invention the salt comprises one or more of the following salts as additive(s): K2CO3, Na2CO3, KHCO3, NaHCO3, KPO3, K3PO4, Na3PO4, K2SO4, Cl, KBr, KCl.

[0056] According to the invention, by using one or more of these additives, it is possible to adjust the melting temperature and the ion exchange behavior of the ion exchange salt and to adapt it to the glass of the glass and / or glass-ceramic article to be treated.

[0057] Furthermore, according to the invention, the ion exchange salt or the molten salt can contain solid components, in particular KCl, K2CO3, K2SO4 or colloidal SiO2, which are present in a non-molten state at a temperature t in the range of 334°C ≤ t ≤ 400°C and serve to adjust the fluidity and viscosity of the molten salt, thus enabling the adhesion of a salt film forming from the molten salt to the glass or glass-ceramic article to be adjusted. Furthermore, by using the aforementioned solid additives, it is possible to form a eutectic of the salt composition, which ensures that all substances relevant for ion exchange, in particular the potassium salt and the carbonates and phosphates necessary for adjusting the melting temperature and the ion exchange behavior, simultaneously transition into a liquid state with a predefined viscosity.

[0058] According to the invention, the surface of the glass or glass-ceramic article is overheated by means of a burner, in particular a gas burner, laser, IR heating, inductive heating or by immersion in a tin melt superheated to a temperature of 400°C to 750°C, preferably 400°C to 650°C, and / or by spraying with liquid tin superheated to a temperature of 400°C to 750°C, preferably 400°C to 650°C.

[0059] Gas burners have proven particularly advantageous in this regard, as they are lightweight and versatile. One advantage of these gas burners is that they can be easily targeted locally and, if necessary, can also be used in pulsed mode by switching the gas supply on and off. Furthermore, the use of one or more lasers to heat the contact zone between glass and salt, as well as the contact materials themselves, has proven extremely advantageous, as a laser can be used to "track" precisely defined areas and thus heat-treat them. The latter is particularly useful when only individual points or lines, such as a seam on a glass or glass-ceramic object, are to be subjected to an ion exchange process.

[0060] According to a further advantageous embodiment of the invention, step d) of the method, ie heating the contact zone of glass and salt as well as the contact materials themselves, can be carried out with simultaneous cooling of a surface of the glass or glass-ceramic article opposite the surface to be heated or, in particular in the case of a hollow body, an inner surface.

[0061] Another important point of the invention is that it is possible according to the invention to precisely control the temperature in a respective dedicated contact zone of glass and salt on the glass or glass ceramic article to be treated and to create different temperature zones in a small area, i.e. with a minimum distance of optimally 5 mm, in order to create regular profiles on the glass or glass ceramic article with a different ion exchange rate and thus exchange ion density and penetration depth of exchange ions.

[0062] This is possible according to the invention in that the intensity, the duration and also the temperature, which is generated on the glass or glass-ceramic object to be treated at specific points, over a large area or in a line, can be precisely regulated and adjusted. In this way, it is also possible to subject very thin glasses to an ion exchange process on one side by simultaneously exposing the other side of the thin glass to warm gas, which, however, has a cooler temperature than the temperature in a reaction zone, i.e. the contact zone between glass and salt during the ion exchange process. Such cooling is possible not only on the opposite side of the glass, but optionally also adjacent to a respective reaction zone.In this way, it is advantageously possible according to the invention to shift previous wall thickness restrictions, or thickness restrictions, with regard to carrying out an ion exchange process towards significantly smaller glass thicknesses.

[0063] According to one embodiment of the invention, the entire surface of the glass or glass-ceramic article can be coated with a salt film and the surface can then be overheated over the entire area or in partial areas.

[0064] Alternatively, it is possible according to the invention to coat the surface of the glass or glass-ceramic article only partially with a salt film, for example by means of a stencil or mask, and then to overheat the surface over the entire area or in partial areas.

[0065] Furthermore, it is possible according to the invention that the superheating of the surface of the glass or glass-ceramic article is repeated after cooling, wherein the cooling is carried out by natural convection and / or forced convection and / or by immersion in the molten salt and / or spraying with the molten salt.

[0066] Furthermore, the composition of the molten salt can be changed for repeated immersion and / or spraying with the molten salt in order to optimize a near-surface ion profile, or ion exchange profile, of the glass surface of the glass or glass-ceramic article.

[0067] According to the invention, the glass or glass-ceramic article is a glass product made of inorganic, non-metallic glass, preferably of oxidic glass, preferably of silicate glass or borosilicate glass or phosphate glass or zinc aluminosilicate phosphate, wherein the silicate glass is preferably aluminosilicate glass or alkali silicate glass, preferably alkali-alkaline earth silicate glass, in particular soda-lime glass.

[0068] Furthermore, the object of the invention is achieved by a plant for producing a glass or glass-ceramic article 20 with increased strength, wherein the plant is particularly suitable for carrying out a method according to the above embodiments.

[0069] The system according to the invention has the following essential components: - at least one holding device for holding the glass or glass-ceramic object, wherein the at least one holding device is movable at least in the vertical direction between an uppermost position and a lowermost position, preferably along a guide or rail (60), and optionally rotatable about a vertical axis of rotation and / or pivotable about a vertical pivot axis and further optionally translatory or rotatable from one position to a next position; - a number of, in particular 2 to 30, preferably 3 to 20, and particularly preferably 4 to 15, respective discrete receiving spaces, preferably each tempered to a certain predetermined elevated temperature, wherein the respective next receiving space has a higher temperature than the respective preceding receiving space; - a number of, in particular 2 to 30, preferably 3 to 20, and particularly preferably 4 to 15, respective discrete receiving spaces, preferably each tempered to a certain predetermined elevated temperature, wherein the respective next receiving space has a lower temperature than the respective preceding receiving space; - a heatable container for holding a molten salt or a salt solution, the container being arranged below the holding device; - a heating device arranged vertically between the uppermost position of the holding device and the container; and - a cleaning device arranged vertically between the uppermost position of the holding device and the container, preferably above the heating device, - and, if appropriate, a heatable container for holding a cooling molten salt, preferably approximately at the level of the heatable container for holding a molten salt or salt solution; - and optionally a heatable container for holding a tin melt, preferably approximately at the level of the heatable container (30) for holding a salt melt or salt solution.

[0070] According to the invention, the cooling salt melt can be used in a first cooling step as long as the glass and / or glass-ceramic article still has a temperature that is above the temperature of the cooling salt melt and can be cooled therein.

[0071] According to a preferred embodiment of the invention, the system for transferring the glass or glass-ceramic article from one receiving space into a respective downstream receiving space in the heating cascade and / or in the cooling cascade preferably has a substantially temperature-insulated transfer device, preferably in the form of a sleeve, for example in the form of a spring basket.

[0072] An important aspect of the system according to the invention lies in particular in the arrangement of its components, which are arranged essentially vertically relative to one another. This allows the holding device, which is designed to hold a glass or glass-ceramic object, for example, by clamping it around a non-treated area of ​​the glass or glass-ceramic object, to be able to move the glass or glass-ceramic object through the various treatment positions defined by the components of the system according to the invention by simply moving it upwards or downwards, to increase the strength of the glass or glass-ceramic object through an ion exchange process.

[0073] For this purpose, the system according to the invention comprises a holding device for holding the glass or glass-ceramic object, for example, a bottle, wherein the bottle is clamped by the holding device, for example, at its spout end. The bottle is thus firmly fixed to the holding device and can be rotated about this axis of rotation and moved up and down in the vertical direction by the holding device, which in turn is rotatable about a vertical axis of rotation, namely in particular about the vertical axis of rotation of the held object, for example, the bottle.

[0074] For this purpose, the holding device comprises at least two holding jaws which can be brought closer together, i.e. closed, to hold the glass or glass-ceramic object and can be moved away from each other, i.e. opened, to release the glass or glass-ceramic object.

[0075] The holding device itself is preferably located on a holding arm that is connected to a rail for up and down movement. The holding arm can be moved up and down along the rail and pivoted laterally if necessary. According to the invention, both the upward and downward movements of the holding arm, and thus of the holding device, as well as the pivoting movement of the holding arm, are performed by servomotors.

[0076] According to a particularly preferred embodiment of the invention, the system according to the invention comprises a plurality of holding devices, each of which is arranged linearly or offset next to one another and, as a whole, defines a so-called beam gripper. This beam gripper thus comprises a plurality of holding devices that can be moved synchronously with one another in a rotational and / or translational manner.According to the invention, each of these holding devices can hold a glass or glass ceramic object and feed this glass or glass ceramic object to different stations for carrying out the process, such as a heating station, a cooling station, a salt coating station, a boost station in which the glass or glass ceramic object is heated on its outermost surface to a temperature above the softening point of the glass or glass ceramic from which the glass or glass ceramic object is made, a cleaning station, a testing station or a final treatment station, i.e. a station after which the completely treated glass or glass ceramic object is discharged from the process.

[0077] According to one embodiment of the invention, the individual holding devices defining the beam gripper can each be moved separately and independently of one another in the vertical direction and / or rotationally and / or inclinably. Alternatively, it is possible for the entire beam gripper to be moved, not each holding device individually, with respect to a vertical movement and / or an inclining movement. In the latter case, only the rotational movement with which the respective glass or glass-ceramic object held by a respective holding device is then still carried out by the holding device, so that in principle each glass or glass-ceramic object held on the beam gripper by a holding device can be moved rotationally around the axis of rotation of the respective holding device independently of the other glass or glass-ceramic objects held on the beam gripper.

[0078] The provision of such beam grippers has the significant advantage according to the invention that not only one glass or glass-ceramic object can be "guided through the process," but rather a large number of glass or glass-ceramic objects can be simultaneously processed. In this way, the productivity of the process can be massively increased, so that by means of the process and using the system according to the invention, it is possible to achieve an output of 50 to 200 strength-enhanced glass or glass-ceramic objects per minute.

[0079] According to the invention, achieving such a high output is possible in that the respective bar grippers are arranged on a transport device which transports a respective bar gripper with the glass or glass ceramic objects attached thereto from one treatment station to the next treatment station.

[0080] This transport device can be designed either as a linear transport device which picks up a predetermined number of glass or glass-ceramic objects at a starting point by means of a bar gripper, wherein the predetermined number results from the number of holding devices arranged on the respective bar gripper.

[0081] After the glass or glass ceramic objects have been picked up by the beam gripper, or rather the holding devices arranged on the beam gripper and guided by the beam gripper, the glass or glass ceramic objects are fed to a respective station, for example a heating station, and treated there while hanging from the beam gripper, i.e. for example, immersed in a heated water bath or a salt bath, so that, in the case of a salt bath, the outside of the glass or glass ceramic object is wetted with salt, but the inside of the glass or glass ceramic object remains free of salt. By guiding the glass or glass ceramic object by means of the holding device, or rather by means of the beam gripper, the vertical movement can be precisely controlled when the glass or glass ceramic object is immersed in a medium, so that it is possible to leave the inside of a hollow glass or glass ceramic object free of medium.

[0082] According to an alternative embodiment, it is also possible for a respective glass or glass ceramic object to be placed in a respective station by the beam gripper, or the holding device holding the glass or glass ceramic object, for example when heating or cooling of the glass or glass ceramic object is caused essentially purely by the atmosphere prevailing in a station and the glass or glass ceramic object is not exposed to any force acting on the glass or glass ceramic object, for example by a fan or the buoyancy of a medium into which the glass or glass ceramic object is immersed, for example.

[0083] According to the invention, the glass or glass-ceramic object can be placed in such a station, in which the glass or glass-ceramic object is placed by a bar gripper or a holding device attached thereto, and then gripped in a next step by another bar gripper or a holding device attached to the other bar gripper, and then subsequently conveyed to another station. In this way, it is possible to transfer a glass or glass-ceramic object from one transport device to another transport device.Such a procedure is extremely advantageous according to the invention since it makes it possible to release the first transport device so that the first transport device is available to receive a further batch of glass or glass-ceramic articles after the bar gripper has been returned to its starting position, while the previous batch of glass or glass-ceramic articles is fed by the second transport device to one or more further stations.

[0084] A significant advantage of using multiple transport devices according to the invention is that, among other things, speed-determining steps of the process, such as heating or cooling the glass or glass-ceramic article, can be divided into several stations in this way without disrupting the timing of the process and thus the achievement of a potentially very high output.

[0085] As mentioned above, a transport device can be designed such that the glass or glass-ceramic objects to be treated are conveyed linearly from one station to the next station; alternatively, however, it is also possible according to the invention to design a transport device as a rotary table, in which glass or glass-ceramic objects to be treated can be held and conveyed either tangentially or radially on respective beam grippers attached to the rotary table.

[0086] In this case, it has proven advantageous according to the invention if a rotary table, on which the glass or glass ceramic objects to be treated are held tangentially, is designed to be multi-angular, ie preferably hexagonal or octagonal, wherein a respective bar gripper is then arranged adjacent to a further bar gripper on a respective edge of the hexagon or octagon.

[0087] In the case of a rotary table in which the respective glass or glass-ceramic objects are arranged radially, the respective bar grippers holding the glass or glass-ceramic objects are accordingly arranged radially on the rotary table and preferably extend radially outwards from the center of the rotary table in the form of a six-pointed or eight-pointed star.

[0088] If a rotary table is used for the process, the glass or glass ceramic objects held by the respective holding devices on a respective beam gripper of the rotary table are advantageously not set down, but remain on the respective beam gripper or the holding devices arranged on the beam gripper for all process steps that are carried out by means of this rotary table transport device.

[0089] At this point, it should be noted that, according to the invention, each "edge" or "beam" of the rotary table, which is each realized by a beam gripper, can be equipped with glass or glass-ceramic objects according to the number of holding devices arranged on the respective beam gripper, which, in the case of the use of a rotary table, are all guided at the same timing and treated in the respective stations.

[0090] In this context, it should also be noted that different transport devices, i.e., both linear and rotary transport devices, can be used for a complete process run. For example, the respective heating and cooling steps, which each proceed at a relatively slow speed, can be implemented using respective rotary tables, each of which relatively slowly transports a large number of glass or glass-ceramic objects through the respective heating and cooling stations, while the rapid steps of applying a molten salt and subsequent heating and, if necessary, cleaning are carried out using a linear transport device.

[0091] In an extremely advantageous manner, the process can be carried out without any downtime, since the individual holding devices on the beam grippers and the individual transport devices enable individual gripping and further transport of the glass or glass-ceramic objects.

[0092] A further advantage of the invention is that, due to the independently acting holding devices on the beam grippers, different glass or glass-ceramic objects can be treated with regard to weight, size and geometry, since the method can be easily and very quickly adapted to the different requirements of the glass or glass-ceramic objects, for example due to their different glass thicknesses and / or geometries.

[0093] A further advantage of the fact that the glass or glass-ceramic objects to be treated are held by respective holding devices is that they are firmly fixed to their respective holding devices, and rattling, falling over, or bumping into each other, as is the case, for example, when transporting glass or glass-ceramic objects on conveyor belts, is extremely advantageously eliminated according to the invention. This is particularly advantageous because, due to the system design according to the invention, disruptions to the process flow are at least minimized and, in the best case, virtually eliminated.

[0094] A further advantage of the method and the system according to the invention is that, due to the rapid changeover of the process parameters required for the process due to different geometries, types of glass, sizes and / or weights of the glass or glass-ceramic objects to be treated, even small batch sizes can be treated in an economically viable manner. Another important point of the system according to the invention is that the heatable container for holding a molten salt or, if appropriate, a salt solution is arranged spatially below the holding device, in particular the holding device in a working position.In this way, it is possible to hold a glass or glass-ceramic object with the holding device and, by moving it downwards, lower it into the interior of the heatable container so that the glass or glass-ceramic object is partially or completely immersed in the molten salt or salt solution contained in the container. The term "completely" in this context means that the glass or glass-ceramic object is immersed so far into the molten salt or salt solution that the holding device holding the glass or glass-ceramic object is still above the molten salt or salt solution.Since the level of the molten salt or salt solution increases due to displacement by the glass or glass-ceramic object when the glass or glass-ceramic object is immersed in the molten salt or salt solution, according to one embodiment of the invention, a sensor or other device is provided which prevents the molten salt or salt solution from touching the holding device or possibly overflowing from the container.

[0095] A further advantage of the invention, which is associated with the fact that the holding device is located in a working position exclusively at least above a bottom of the container and otherwise above the container, is also that when the glass or glass-ceramic object is moved out of the molten salt or salt solution, any salt dripping from the glass or glass-ceramic object drips back into the container and does not contaminate the surroundings of the container.

[0096] A further important point of the invention is that the heating device provided according to the invention is arranged in the vertical direction between the uppermost position of the holding device and the container, namely in particular the upper edge of the container, so that the glass or glass-ceramic article coated with molten salt or salt solution can be subjected to heat, namely to initiate and carry out the ion exchange process, immediately and essentially without heat loss after the glass or glass-ceramic article has left the container, or the molten salt or salt solution, and has been freshly coated with the ion exchange salt.

[0097] Similarly, another important point of the invention is that the cleaning device is also arranged vertically between the uppermost position of the holding device and the container, i.e. again an upper edge of the container, so that salt which falls off the glass or glass-ceramic object after carrying out the ion exchange process in the course of cleaning the surface of the glass or glass-ceramic object can fall back into the container.

[0098] According to a preferred embodiment of the invention, the container has a lid which can preferably be opened and closed in a horizontal direction and which, in the closed state, preferably has or forms a support surface on an upper side.

[0099] The lid of the container can thus advantageously be used as a storage area for a glass or glass-ceramic object to be treated, on which the glass or glass-ceramic object is in a waiting position before being gripped by the holding device. In this waiting position, the glass or glass-ceramic object is tempered by the heat rising from the container. After the glass or glass-ceramic object has been gripped by the holding device of the system according to the invention, the glass or glass-ceramic object is lifted from the lid of the container in such a way that the glass or glass-ceramic object no longer touches the lid of the container, so that the lid of the container can be opened and the glass or glass-ceramic object can be immersed in the molten salt or salt solution for coating with ion exchange salt.

[0100] According to the invention, the heating device comprises at least one burner, in particular a gas burner, and / or at least one laser and / or at least one infrared heater and / or at least one inductive heater and / or a container for receiving liquid tin heated to a temperature of 400°C to 750°C, preferably 400°C to 650°C.

[0101] During the process, this container with liquid tin can be used as an immersion bath for the glass or glass-ceramic object to be treated. In addition, tin can be taken from the container with liquid tin in order to spray the glass or glass-ceramic object to be treated with superheated liquid tin. According to the invention, spraying with liquid tin or dipping in liquid tin can serve both to precondition the glass or glass-ceramic object to be treated, i.e. to heat it to the initial process temperature of 300°C to 750°C, preferably 350°C to 500°C, and to post-treat the glass or glass-ceramic object after the actual ion exchange process and, if appropriate, after cleaning the glass or glass-ceramic object and, depending on the process temperature, to cool it down in a deliberate and controlled manner during the ion exchange and during cleaning.

[0102] In addition, the salt-coated glass or glass-ceramic article can also be immersed in the container containing liquid tin or sprayed with liquid tin to carry out the ion exchange process. The latter can be particularly advantageous when treating very thin glass or glass-ceramic articles, since the temperature during the ion exchange process when using liquid tin can be lower due to the very high heat transfer coefficient resulting from the use of liquid tin than, for example, with flame treatment, where a flame temperature can be in the range of 1300°C to 1400°C, or with heating by infrared or induction. This advantageously prevents any deformation of the glass or glass-ceramic article, or even eliminates the risk of such deformation.

[0103] According to one embodiment of the invention, the heating device can be formed from a plurality of heating elements arranged to form at least one, preferably two, linear and / or an optionally curved surface forming heating element array(s).

[0104] According to the invention, the heating elements of the heating device can be electronically controlled individually and / or in dependence on one another with regard to position, intensity, heating temperature and, if necessary, pulsed, duty cycle.

[0105] In this way, it is possible in an extremely advantageous manner to apply heat to specific individual positions on the glass or glass-ceramic object to be treated or to heat larger areas evenly or even specifically unevenly in order to initiate and effect an ion exchange reaction or an ion exchange process.

[0106] A respective heating element array can, for example, be approximated to the outer shape of the glass or glass-ceramic object and in this way, for example, “simulate” the cylindrical body on the one hand and the conical neck of a bottle on the other hand in order to apply a predefined temperature profile to both the body and the neck of the bottle.

[0107] The heating element array can comprise individual heating elements arranged in a substantially vertical direction, each of which can be controlled separately. Furthermore, it is also possible to provide several rows of heating elements arranged in a substantially vertical direction, wherein these rows can be aligned substantially parallel to one another and, if necessary, arranged opposite one another, so that the glass or glass-ceramic object to be heated can be heated from two or more sides simultaneously.

[0108] For this purpose, the individual heating elements can be located on individual support arms, each of which can be moved independently of one another, so that the individual heating elements can be functionally combined to form different heating element arrays.

[0109] Furthermore, the holding arms of the individual heating elements can also move the heating elements from a working position to a rest position, whereby the rest position, in which the heating elements are moved to an outer position, enables vertical movement of even large glass or glass-ceramic objects.

[0110] Furthermore, as mentioned above, the system according to the invention also comprises a cleaning device, namely a dry cleaning device, wherein the cleaning device comprises a stripping device and / or a blower device, in particular a hot gas blower device.

[0111] According to a preferred embodiment of the invention, the dry cleaning device is provided in the form of a blower cleaning system, which can optionally be equipped with a suction device to convey salt removed from the glass or glass-ceramic object by airflow into a collecting container. The salt removed from the glass or glass-ceramic object can then, depending on the desired composition, optionally be returned to the molten salt or salt solution containing the ion exchange salt.

[0112] In this context, it should also be noted that, according to one embodiment of the invention, the glass or glass-ceramic object to be cleaned can be surrounded by a type of apron during the cleaning process using gas, preferably compressed air, which prevents the blown-off salt from contaminating the environment. The apron can be open at the top and / or bottom, allowing a suction device to act on a respective opening as desired.

[0113] Furthermore, the dry cleaning device used according to the invention can also comprise a stripping device, which can optionally be used when the glass or glass-ceramic article has already largely cooled down. It should be noted that such a stripping device is merely an optional feature of the system according to the invention.

[0114] Furthermore, according to a further embodiment of the invention, a funnel device is provided above the opening of the container, which funnel device can optionally be displaced and / or pivoted or attached in any other way, which is particularly advantageous when falling salt is to be collected in a collecting container or optionally fed to the container containing the molten salt or salt solution.

[0115] According to an alternative embodiment of the invention, a collecting cup or collecting tray can be provided below the dry cleaning device, which in the case of fan cleaning can also function as fan cooling, instead of a funnel device, in order to collect salt falling from the glass or glass-ceramic object during the cleaning and cooling process and to supply it for further recycling or disposal.

[0116] According to the invention, such a collecting tray or cup can be pivoted or otherwise positioned beneath the glass or glass-ceramic object to be cleaned when the cleaning and cooling process step according to the invention is carried out. Subsequently, the collecting tray or cup can be removed again, so that the holding device can be lowered in a direction, particularly in a purely vertical direction, from its maximum height until the glass or glass-ceramic object can be immersed in the salt bath or tin bath.

[0117] According to a particularly preferred embodiment of the invention, the system can have a plurality, in particular between five and thirty, preferably between ten and twenty, holding devices, which are movable, preferably synchronously, along the guide or rail and optionally rotatable about a vertical axis of rotation, preferably synchronously, and / or optionally pivotable about a vertical pivot axis, preferably synchronously, wherein in particular each holding device is / are assigned a heating device and optionally a cleaning device, and wherein the heatable container for holding a molten salt or salt solution and optionally the heatable container for holding a molten tin are each designed in a trough-like manner, in particular oblong or oval, and are arranged below the plurality of holding devices.

[0118] In this way, it is possible according to the invention to treat not just one glass or glass-ceramic object during an ion exchange process cycle, but a large number of glass or glass-ceramic objects simultaneously, depending on the number of holding devices. Each glass or glass-ceramic object is held by its own holding device and can simultaneously be moved and / or rotated vertically along the guide or rail. For this purpose, the individual holding devices are attached to a common holding arm, which in turn is connected to the guide or rail. Each holding device itself is designed such that the object it holds can be rotated at least about a vertical axis. The entire holding arm, to which the individual holding devices are attached, can in turn be pivoted and, if necessary, moved translationally.In this way, it is possible to simultaneously immerse all glass or glass-ceramic objects attached to the holding devices in a common tin bath and / or simultaneously in a common molten salt bath or remove them again from it. Furthermore, they can be simultaneously subjected to the heating device according to the invention for carrying out the ion exchange process, and subsequently to a cleaning and cooling process that is individual for each glass or glass-ceramic object or common for all attached glass or glass-ceramic objects. In this way, the cycle rate of the process can be significantly increased using this advantageous embodiment of the invention.

[0119] According to a further embodiment of the invention, the holding device(s), the heating device(s) and the cleaning and cooling device(s) as well as, if appropriate, the container(s) for receiving molten salt or tin and, if appropriate, the funnel device are designed as an associated system unit.

[0120] Such a system unit offers a significant advantage according to the invention, namely an extremely compact design of the system, which makes it possible to arrange several of these systems essentially parallel to one another and to feed them with glass or glass-ceramic objects to be treated in combination with at least one feed belt, for example a conveyor belt, from which a robot picks up the glass or glass-ceramic objects to be treated and places each one on the lid of the container containing the molten salt or salt solution, from where further treatment takes place in the manner described above, in that the holding device in turn picks up the glass or glass-ceramic object to be treated and feeds it to further treatment, namely initially coating with ion exchange salt, a subsequent heat treatment, in particular fire polishing, and subsequent dry cleaning.Following this ion exchange process and subsequent dry cleaning, the holding device of the system according to the invention can pivot outward and place the glass or glass-ceramic article, with its strength improved, on a discharge belt, again for example a conveyor belt. In this way, the invention makes it possible to treat a large number of glass or glass-ceramic articles simultaneously or virtually simultaneously, achieving a very high cycle rate in the strength optimization of glass articles.

[0121] In this context, it should also be noted that the method and the device, i.e. system, according to the invention, unlike methods and systems known from the prior art, are eminently suitable for subjecting only one side of a glass or glass-ceramic article, for example an outer side or only one side of a flat glass article or only one side of a tube, to an ion exchange process. In the same way, however, it is also possible with the method and the system according to the invention to subject the inside of hollow bodies made of glass or glass-ceramic to an ion exchange process, as long as the hollow body has an access opening, such as a bottle or a tube, through which a molten salt can be poured or sprayed into the interior of the hollow body.Due to the attachment of the heating elements used according to the invention to support arms, it is possible to insert the respective heating elements into the interior of a hollow body coated with ion exchange salt and to heat the hollow body from the inside in such a way that an ion exchange process is initiated and carried out. Subsequently, any remaining salt can be blown out of the hollow body treated on its inside.

[0122] Furthermore, it should be noted that the holding device according to the invention, as mentioned above, is rotatable about a vertical axis in order to rotate the glass or glass-ceramic article held by the holding device about its vertical axis. Such a rotational movement can take place as a rotary movement or as an oscillating movement, the latter being particularly useful during fire polishing, i.e., heat treatment, when glass or glass-ceramic articles whose axial extent deviates from a round shape and is, for example, oval or angular are to be subjected to the ion exchange process.

[0123] Furthermore, it should be noted that the device according to the invention comprises a station for quality inspection of the glass and / or glass-ceramic object to be treated, which is arranged on the system side between a feed station for the glass and / or glass-ceramic object to be treated and the first receiving space of the heating cascade. At this quality inspection station, a glass and / or glass-ceramic object to be treated is non-destructively inspected for any quality defects, such as inclusions or surface defects, and is rejected if such defects are present.

[0124] Furthermore, the device according to the invention further comprises, upstream of a discharge station, a station for applying a surface protective layer, for example made of wax, to a finished treated glass and / or glass ceramic article in order to protect the finished glass and / or glass ceramic article from possible damage, for example by impact.

[0125] Further embodiments of the invention emerge from the subclaims.

[0126] The invention is described below using exemplary embodiments, which are explained in more detail with reference to the figures. Herein: Fig. 1 a schematic representation of a system according to the invention; Fig. 2 a schematic representation of a first embodiment of a linear transport device according to the invention in perspective view; Fig. 3 a schematic representation of the embodiment of a linear transport device according to the invention according to Fig. 2 in side view; Fig. 4 a schematic representation of a detailed view of the embodiment of the linear transport device according to the invention according to Fig. 3; Fig. 5 a schematic representation of a further embodiment of a tangential transport device according to the invention in side view; Fig. 6 a schematic representation of the embodiment of a tangential transport device according to the invention according to Fig. 5 in perspective view; Fig. 7 is a schematic side view of another embodiment of a radial transport device according to the invention; Fig. 8 a schematic representation of the embodiment of a radial transport device according to the invention according to Fig. 7 in perspective view.

[0127] In the following description, the same reference numbers are used for identical and equivalent parts.

[0128] Fig. 1 shows a schematic representation of a system 100 according to the invention for increasing the strength of glass using an ion exchange process. The system 100 according to the invention has a holding device 10 that is rotatable about a vertical axis of rotation 22 in order to be able to rotate a glass or glass-ceramic object 20 held by the holding device 10 about its vertical axis. The holding device 10 is fastened by means of a holding arm 26 to a guide, or rail 60, by means of which the holding device 10 can be moved in the vertical direction parallel to a lifting / pivoting axis 24. According to an optional embodiment, the holding arm 26 can be pivoted together with the holding device 10 about the pivoting axis 24.

[0129] Below the holding device 10 there is a container 30 which, according to Fig. 1 has a two-part cover 32, the upper side of which can serve as a support surface 34.

[0130] Furthermore, the system 100 according to the invention has Fig. 1 a heating device 40 comprising a plurality of heating elements 44 attached to support arms 42, which according to Fig. 1 are arranged in a substantially linear vertical heating element array. The holding arms 42 of the heating elements 44 are individually pivotable; the heating elements 44 themselves are electronically controllable independently of one another with regard to their position, intensity, heating temperature, and duty cycle.

[0131] A collecting cup is arranged below the heating device 40 to collect any salt falling from the glass or glass-ceramic object.

[0132] Furthermore, the system 100 according to the invention has a cleaning device 50, which simultaneously serves as a cooling device and according to Fig. 1 is arranged below the heating device 40 and comprises a blower in the form of a nozzle 54, with which salt adhering to the glass or glass-ceramic object 20 after an ion exchange process can be blown off for cleaning.

[0133] As further stated Fig. 1, the two-part lid 32 of the container 30 can be opened by means of an opening mechanism 90 in order to lower a glass or glass-ceramic object 20, which is fastened to the holding device 10 or is held by the holding device 10, into a molten salt (not shown) located in the container 30, so that the glass or glass-ceramic object 20 is coated with the molten salt.

[0134] Fig. Figure 2 shows a schematic perspective view of a first embodiment of a linear transport device according to the invention, in which a bar gripper 110 can be guided along its suspension in a linear direction over several stations. A plurality of holding devices are arranged on the bar gripper 110, with which a corresponding plurality of, in this case, fourteen bottles 20 are held, which can be moved to the respective processing stations by means of the bar gripper.

[0135] Fig. 3 shows a schematic representation of the embodiment of the linear transport device according to the invention according to Fig. 2 in side view and

[0136] Fig. 4 shows a schematic representation of a detailed view of the embodiment of the linear transport devices 120 according to the invention according to Fig. 3, in which the lifting axis 24, with which the glass or glass-ceramic object 20, in this case a bottle, can be moved in the vertical direction and rotated about the rotation axis 22.

[0137] Fig. Fig. 5 shows a schematic representation of another embodiment of a tangential transport device 120 according to the invention in side view, which in Fig. 6 is shown in perspective view. It can be seen that the respective beam grippers 110 are arranged along the respective edges of the transport device 120. According to Fig. 6, the connections of the respective beam grippers 110 to the rotary frame, with which the rotary table can be moved, are omitted for clarity. The respective glass or glass-ceramic objects 20 are located below the beam grippers 110 and are held by respective holding devices, not designated in more detail. The transport device 120 according to the Fig. 5 and Fig. The embodiment of the invention shown in Figure 6 is designed in the shape of a hexagon and accordingly has six bar grippers 110, which are each arranged adjacent to one another along the outer edges of the hexagon.

[0138] Fig. Fig. 7 shows a schematic representation of a further embodiment of a radial transport device 120 according to the invention in plan view, this embodiment in Fig. 8 in perspective view. The respective beam grippers 110 extend radially outwards from the center of the transport device 120. As shown in the Fig. 7 and Fig. 8, the transport device 120 according to this embodiment has a total of eight bar grippers 110 in a symmetrical alignment, under which respective glass or glass ceramic objects 20 are held by respective holding devices not designated in more detail. Example 1:

[0139] A drinking bottle made of soda-lime glass with a volume of 600 ml and a mass of 415 g is preheated from room temperature to 450°C in a muffle furnace in one hour. The bottle is transferred to a robot gripper arm and immersed in a 430°C hot potassium nitrate melt. The bottle is immersed only far enough so that no molten salt runs into the bottle (one-sided ion exchange). After a holding time of 10 s, the gripper arm removes the bottle from the salt bath at a speed of 3 m / min. The bottle with the salt film is immediately superficially superheated to approximately 620°C in 20 s using an arrangement of four natural gas burners. During the flame treatment, the bottle rotates at 5 rpm to ensure the most even heating possible. The robot arm then pulls the bottle three times through a ring nozzle pressurized with hot air to blow off the salt film.The drawing speed is 3 m / min, and the cleaning air has a temperature of 450°C. Immediately afterward, the robot arm places the bottle in a cooling oven. Example 2:

[0140] In order to increase the depth of the ion exchange and thus the increase in strength, the process is carried out analogously to Example 1, but after the flame treatment, the bottle is immersed in the salt bath again, pulled out again immediately after the immersion process and the flame treatment is repeated before the salt film is cleaned off.

[0141] In terms of the process, the glass or glass ceramic object 20, in this case a bottle, can also be preheated on a feed belt, i.e. a conveyor belt, in a heating channel to a temperature of 430°C and then picked up from the conveyor belt by a robot and placed on the support surface 34 of the lid 32 of the container 30. The glass or glass ceramic object 20, i.e. in this case the bottle, is then gripped at its upper open end by the holding device 10 and moved downwards along the rail 60 until the glass or glass ceramic object 20 is immersed in the molten salt to just below the holding device 10, wherein before a downward movement of the bottle or during the downward movement of the bottle, the lid 32 of the container 30 has opened so that the molten salt is accessible from above. After the bottle, or the glass or glass ceramic object 20, has been filled with the molten salt, i.e.Once the glass or glass-ceramic article 20 has been coated with the ion exchange salt, the glass or glass-ceramic article 20 is withdrawn from the molten salt and the container 30 by the holding device 10 and positioned between the holding arms 80, or rather the heating elements 90, which are fastened to the holding arms 80, in such a way that the heating elements 90, by heating and overheating the salt adhering to the glass or glass-ceramic article 20 as well as the surface of the glass or glass-ceramic article 20 itself, i.e., therefore, the contact surface between glass and salt as well as the reaction components themselves, cause an ion exchange process to be initiated and take place. This ion exchange process takes place at a temperature of 430°C for a period of 0.5 minutes.Immediately following the ion exchange process, according to the invention, a fire polish is carried out in the same position for 20 seconds, during which a surface temperature of greater than 700°C, preferably 800°C, is reached on the surface of the glass or glass-ceramic object. This is followed, optionally, by a further immersion, or optionally several times, of the glass or glass-ceramic object 20 into the salt bath, which has a temperature of 430°C, followed by an optional further fire polish, again at a surface temperature of greater than 700°C. After the fire polishing, a dry cleaning takes place by blowing hot air onto the glass or glass-ceramic object 20, which blows off any salt adhering to it. Simultaneously with the blowing off of salt, the glass or glass-ceramic object is cooled, which is then continued in a controlled and rapid manner on a cooling belt.It should be noted at this point that the method described above is scalable with the aid of a robot, allowing simultaneous and parallel treatment of 10, 20, or more glass or glass-ceramic objects. Control of the components, such as the holding device 10, heating device 40, heating elements 90, as well as the associated process steps, such as opening and closing the container 30, raising and lowering the holding device 10, pivoting the holding arms 70 and 80, and controlling the cleaning device 50, is carried out electronically according to the invention.

[0142] At this point, it should be noted that all parts described above, viewed individually and in any combination, particularly the details shown in the drawings, are claimed as essential to the invention. Modifications to these are familiar to those skilled in the art. List of reference symbols 10 Holding device 20 glass or glass-ceramic object 22 axis of rotation 24 Lifting axis / swivel axis 26 Holding arm 30 containers 32 lids 34 support surface 40 Heating device 42 Holding arm 44 heating elements 50 Cleaning device / cooling device 52 Holding arm 54 nozzle 60 rail 70 collecting cup 80 frame 90 Opening mechanism 100 system 110 beam grabs 120 Transport device QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 3 615 322 A [0005, 0009] WO 2022 / 049 206 A1 [0006, 0007]

Claims

[1] Strength-enhanced glass or glass-ceramic article manufactured by the following steps: a) Providing an article made of glass or glass ceramic (glass or glass ceramic article) with a temperature in the range from 300°C to 750°C, preferably 350°C to 500°C, but in any case below a softening point (Littleton point) of the glass or glass ceramic, in particular by means of a heating cascade which comprises a number of, in particular 2 to 30, preferably 3 to 20, and particularly preferably 4 to 15, respective discrete receiving spaces, preferably each heated to a certain predetermined elevated temperature, wherein the respective next receiving space has a higher temperature than the respective preceding receiving space; b) providing a molten salt or salt solution containing exchange ions; c) subsequently applying the molten salt or salt solution to at least a first region of the glass or glass-ceramic article; d) subsequent heating, in particular superheating, of the surface of the glass or glass-ceramic article in the first region of the applied salt melt or salt solution for a period of time in the range from 1 s to 5 min, preferably 3 s to 40 s and particularly preferably 4 s to 20 s, to a temperature close to the softening point, in particular to a temperature of 20°C to 200°C, preferably 30°C to 150°C and particularly preferably 50°C to 100°C above a softening point (Littleton point) of the glass and / or the glass or glass-ceramic article; e) subsequent dry removal of salt present on the surface of the glass or glass-ceramic article, preferably by blowing with warm gas, preferably with air having a temperature in the range from 200°C to 500°C, preferably at 230°C to 400°C and particularly preferably at 250°C to 350°C; f) subsequent cooling of the glass or glass-ceramic article over a period of time in the range from 3 minutes to 30 minutes, preferably from 4 minutes to 20 minutes and particularly preferably from 5 minutes to 10 minutes to a temperature below 300°C, preferably below 200°C and particularly preferably below 150°C, in particular to a temperature between room temperature and 90°C±5K, in particular by means of a cooling cascade which comprises a number of, in particular 2 to 30, preferably 3 to 20, and particularly preferably 4 to 15, respective discrete receiving spaces, each preferably heated to a certain predetermined elevated temperature, wherein the respective next receiving space has a lower temperature than the respective preceding receiving space. [2] Glass or glass-ceramic article according to claim 1, characterized bythat the preheated glass or glass-ceramic article is coated in step c) by dipping into a molten salt (dip coating), wherein an immersion time is between 5 s and 24 hrs, preferably between 5 s and 30 min and particularly preferably between 5 s and 15 min. [3] Glass or glass-ceramic article according to claim 1, characterized by that the preheated glass or glass-ceramic object is coated by spraying it with a molten salt or salt solution. [4] Glass or glass-ceramic article according to one of the preceding claims, characterized by that the exchange ions are potassium ions and a salt used for the ion exchange is a potassium salt, preferably potassium nitrate (KNO3), wherein the salt preferably contains one or more of the following salts as additive(s): K2CO3, Na2CO3, KHCO3, NaHCO3, KPO3, K3PO4, Na3PO4, K2SO4, KI, KBr, KCl. [5] Glass or glass-ceramic article according to one of the preceding claims, characterized by that the salt melt contains solid components, in particular KCl, K2CO3, K2SO4, or colloidal SiO2, at a temperature t in the range of 334°C ≤ t ≤ 400°C. [6] Glass or glass-ceramic article according to one of the preceding claims, characterized by that the superheating of the surface of the glass or glass-ceramic article is carried out by means of a burner, in particular a gas burner, laser, IR heating, induction heating or by immersion in a tin melt heated to a temperature of 400°C to 750°C, preferably 400°C to 650°C, and / or by spraying with liquid tin heated to a temperature of 400°C to 750°C, preferably 400°C to 650°C. [7] Glass or glass-ceramic article according to one of the preceding claims, characterized bythat step d) is carried out with simultaneous cooling of a surface of the glass or glass-ceramic article opposite the surface to be heated or, in particular in the case of a hollow body, an inner surface. [8] Glass or glass-ceramic article according to one of the preceding claims, characterized by that the entire surface of the glass or glass-ceramic object is coated with a salt film of the molten salt or salt solution and then the surface is overheated over the entire area or in parts of it. [9] Glass or glass-ceramic article according to one of the preceding claims 1 to 6, characterized by that the surface of the glass or glass-ceramic object is only partially coated with a salt film, for example by means of a stencil or mask, and then the surface is overheated over the entire area or in parts of it. [10] Glass or glass-ceramic article according to one of the preceding claims, characterized by that the superheating of the surface of the glass or glass-ceramic article is repeated after cooling, the cooling being carried out by natural convection and / or forced convection and / or by immersion in the molten salt and / or spraying with the molten salt. [11] Glass or glass-ceramic article according to claim 10, characterized by that upon repeated immersion in the molten salt and / or spraying with the molten salt, the composition of the molten salt is changed in order to optimize a near-surface ion profile of the glass surface of the glass or glass-ceramic article. [12] Glass or glass-ceramic article according to claim 1, characterized bythat the glass or glass-ceramic article is a glass product made of inorganic, non-metallic glass, preferably of oxidic glass, preferably of silicate glass or borosilicate glass or phosphate glass or zinc-aluminosilicophosphate glass, and wherein the silicate glass is preferably aluminosilicate glass or alkali silicate glass, preferably alkali-alkaline earth silicate glass, in particular soda-lime glass. [13] Glass or glass-ceramic article according to one of the preceding claims, characterized by that providing the article made of glass or glass ceramic with a temperature in the range of 300°C to 750°C, preferably 350°C to 500°C, but in any case below a softening point (Littleton point) of the glass or glass ceramic, - by immersing the glass or glass-ceramic article in a molten tin heated to a temperature of 300°C to 750°C, preferably 350°C to 500°C; or - by spraying with liquid tin heated to a temperature of 300°C to 750°C, preferably 350°C to 500°C; or - by a step-by-step, successive positioning of the glass or glass-ceramic object in, in particular 2 to 30, preferably 3 to 20, and particularly preferably 4 to 15, respective discrete receiving spaces, preferably each heated to a certain predetermined elevated temperature, wherein the next receiving space in each case has a higher temperature than the previous receiving space, wherein preferably a first receiving space, preferably using tempered water, is used to heat the glass or glass-ceramic object to a temperature below a boiling point of water and subsequent receiving spaces are used to further successively increase the temperature of the glass or glass-ceramic object up to the desired final temperature. [14] Glass or glass-ceramic article according to one of the preceding claims, characterized by that a transfer of the glass or glass-ceramic article in the heating cascade and / or in the cooling cascade is carried out in a substantially temperature-insulated environment, preferably by means of a sleeve, for example in the form of a spring basket. [15] Plant for producing a glass or glass-ceramic article (20) with increased strength according to one of the preceding claims, with - at least one holding device (10) for holding the glass or glass-ceramic object (20), wherein the at least one holding device (10) is movable at least in the vertical direction between an uppermost position and a lowermost position, preferably along a guide or rail (60), and optionally rotatable about a vertical axis of rotation (22) and / or pivotable about a vertical pivot axis (24) and further optionally translatory or rotatable from one position to a next position; - a number of, in particular 2 to 30, preferably 3 to 20, and particularly preferably 4 to 15, respective discrete receiving spaces, preferably each tempered to a certain predetermined elevated temperature, wherein the next receiving space in each case has a higher temperature than the previous receiving space in each case; - a number of, in particular 2 to 30, preferably 3 to 20, and particularly preferably 4 to 15, respective discrete receiving spaces, preferably each tempered to a certain predetermined elevated temperature, wherein the respective next receiving space has a lower temperature than the respective preceding receiving space; - a heatable container (30) for holding a molten salt or salt solution, wherein the container (30) is arranged below the holding device (10); - a heating device (40) arranged vertically between the uppermost position of the holding device (10) and the container (30); and - a cleaning device (50) arranged vertically between the uppermost position of the holding device (10) and the container (30), - and optionally a heatable container for holding a cooling salt melt, preferably approximately at the level of the heatable container (30) for holding a salt melt or salt solution; - and optionally a heatable container for holding a tin melt, preferably approximately at the level of the heatable container (30) for holding a salt melt or salt solution. [16] Plant according to claim 15, characterized by that the system for transferring the glass or glass-ceramic article from a receiving space into a respective downstream receiving space in the heating cascade and / or in the cooling cascade preferably has a substantially temperature-insulated transfer device, preferably in the form of a sleeve, for example in the form of a spring basket. [17] Installation according to one of the preceding claims 15 to 16, characterized bythat the container (30) and optionally the container for receiving the cooling salt melt has a lid (32) which can preferably be opened and closed in the horizontal direction and which, in the closed state, preferably has or forms a support surface (34) on an upper side. [18] Installation according to one of the preceding claims 15 to 17, characterized by that the heating device has at least one burner, in particular a gas burner, and / or at least one laser and / or at least one infrared heater and / or at least one inductive heater and / or a container with liquid tin heated to a temperature of 400°C to 750°C, preferably 400°C to 650°C. [19] Installation according to one of the preceding claims 15 to 18, characterized by that the heating device is formed from a plurality of heating elements which are arranged to form at least one, preferably two, linear and / or planar heating element array(s). [20] Installation according to one of the preceding claims 15 to 19, characterized by that the heating elements of the heating device can be electronically controlled individually and / or in dependence on one another with regard to position, intensity, heating temperature and, if necessary, pulsed, duty cycle. [21] Installation according to one of the preceding claims 15 to 20, characterized by that the cleaning device (50) has a scraping device and / or a blower device, in particular a hot gas blower device. [22] Installation according to one of the preceding claims 15 to 21, characterized by that a substantially horizontally displaceable and / or pivotable funnel device is provided above an opening of the container (30). [23] Installation according to one of the preceding claims 15 to 22, characterized byin that the system has a plurality of, in particular between 5 and 30, preferably between 10 and 20, holding devices (10) which together form a beam gripper (110) and are movable, preferably synchronously, in particular along the guide or rail (60) and, if appropriate, rotatable about a vertical axis of rotation (22), preferably synchronously, and / or if appropriate, pivotable about a vertical pivot axis (24), preferably synchronously, wherein in particular each holding device (10) and / or each beam gripper (110) is / are assigned a heating device (40) and, if appropriate, a cleaning device (50), and wherein the heatable container (30) for holding a molten salt or salt solution and, if appropriate, the heatable container for holding a molten tin is / are each designed in the manner of a trough, in particular oblong and / or oval, and is / are arranged below the plurality of holding devices (10). [24] Installation according to one of the preceding claims 15 to 23, characterized by that the at least one holding device (10), the heating device (40) and the cleaning device (50) and optionally the container (30) and the funnel device and / or optionally the container for the cooling salt melt and / or optionally the container for the tin melt are designed as an associated system unit (100).

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