Method for determining batch thickness in an all-electric glass tank

Abstract

This invention provides a method for detecting and evaluating data on batch coatings and / or glass melts in an all-electric cold-top melting tank for melting glass, as well as the use of this method in a glass manufacturing method. [Solution] Data or a topography map is detected at regular time intervals during tank operation, the temporal changes in the topography are evaluated, and a global topography is created. Data from sensor 160 can be detected during the batch feeding process. Furthermore, the batch coating topography that is optimal for each melting process can be determined and this topography can be used to control the local feed amount.

Description

Technical Field

[0001] The present invention relates to a method for detecting and evaluating data on batch coating and / or glass melt, particularly in an all-electric cold top melting tank for melting glass, and to the use of this method in a method for producing glass.

[0002] Technical Background / Prior Art In order to reduce CO2 emissions in glass production, all-electric melting tanks are increasingly being used in the production of glass and glass ceramics.

[0003] In an all-electric melting tank, generally, the entire free surface of the glass melt is covered with a batch. This closed batch coating thermally separates the glass melt from the upper furnace (Oberofen), whereby the surface temperature of the glass melt is reduced from about 1400 °C to 1650 °C to about 200 °C to 400 °C. On the one hand, this maximizes the melting performance and significantly improves the energy efficiency of the melting tank. The significantly cooler upper furnace further reduces the risk to the devices provided in the upper furnace, such as the feeding machine, and the upper furnace materials, or reduces the requirements for the structure of the upper furnace with respect to heat load resistance.

[0004] Therefore, during operation of an all-electric melting tank, means are usually taken to ensure a closed batch coating across the entire surface of the melting tank. For this purpose, the thickness of the batch coating is measured locally and the batch feed is correspondingly adapted.

[0005] It is possible to manually determine the batch thickness (temporally and spatially) at individual points by means of a rabbling rod with a rod through a side feed opening. This measurement method has risks for humans and for the process when the electric tank heating is on, and also requires the use of personnel. Furthermore, the batch thickness can only be measured locally and relatively inaccurately at just one location.

[0006] Since the batch coating temperature depends on the batch coating thickness, the batch coating thickness can be determined from the measured temperature. International Publication No. 8002833 and U.S. Patent No. 3980460 describe a movable feeder for a cold-top tank in which the batch coating temperature is measured by an IR sensor or thermal sensor. If an excessively high temperature of the batch coating is detected at an individual point, a relatively large batch is added to the batch coating at that point.

[0007] In the prior art, there are methods for maintaining a constant glass level by measuring the distance between the batch covering and the feeder, thereby determining the height of the glass level in the melting tank, and controlling the feed rate. For example, U.S. Patent No. 4,194,077 and U.S. Patent No. 4,302,623 describe movable feeders for cold-top tanks, each equipped with an ultrasonic sensor at its end for measuring the distance to the batch covering.

[0008] Conventional technologies have not considered it necessary to further collect data on batch coating for the operation of the melting tank. At the same time, the increasing importance of electric melting tanks has created a need to optimize the operation of such tanks.

[0009] Problems of the invention Therefore, the object of the present invention was to provide a method for optimizing the operation of an all-electric melting tank, particularly one that can respond to the melting process and its fluctuations by locally and temporally adapted feed rates and selectively locally and temporally adapted melting rates, and to provide a stable and energy-efficient method for manufacturing glass.

[0010] Brief description of the invention In particular, the present invention provides a method for detecting and evaluating data on batch coating, optionally molten glass, and optionally glass level, in a preferably all-electric cold-top melting tank for melting glass, the following steps: - The step of preparing at least one sensor 160 for non-contact detection of data about the batch coating 150 at at least the end of the arm 120 of the feed machine into which the batch is added to the glass molten, -(a) repeatedly detect and store data about the batch coating 150 by at least one sensor 160 while the melting tank 100 is in operation, (2) detect data from at least 10 different positions on the batch coating, preferably at least 100 different positions, and associate the data with the positions of the arm 120 or the end of the sensor 160, The present invention relates to a method comprising the steps of processing detected data to create a topographic map of a batch covering 150, preferably a global topographic map and / or preferably an optimal topography.

[0011] The present invention further relates to the use of a specific method according to the present invention for controlling batch equipment in a glass manufacturing method. [Brief explanation of the drawing]

[0012] [Figure 1] This figure schematically shows a cross-section of a cold-top melting tank for carrying out the method according to the present invention. [Figure 2] This is a schematic plan view showing the arm of a feed machine for carrying out the method according to the present invention. [Figure 3] This diagram schematically shows the measurement of batch coating, or the topography of a batch coating that will be created. [Figure 4] This figure schematically shows a cross-section of a cold-top melting tank equipped with an additional microwave heating section for carrying out the method according to the present invention.

[0013] Detailed description of the invention The present invention relates to a method for detecting and evaluating data on batch coating and / or glass levels in an all-electric cold-top melting bath, particularly for melting glass, and for utilizing this data in an optimized melting process. Here, data relating to both spatial and temporal variations in batch thickness can be identified and processed, and a batch coating topography can be created.

[0014] The term “topography” is understood here as a description or representation of the three-dimensional structure of the batch coating surface (see Figure 3). The term “global topography” is understood as the topography of the batch coating surface that changes during the melting process. The term “optimal topography” is understood as the topography of the batch coating that can be identified by the method according to the present invention and that enables the most stable process and / or best glass quality for a particular melting process.

[0015] Within the framework of this invention, it has been recognized that the operation of an all-electric coldtop tank can be improved and stabilized by extensively detecting and evaluating data regarding batch coating and glass levels. Furthermore, by extensively detecting and evaluating data regarding batch coating and glass levels, the operation of the all-electric coldtop tank can be monitored, and in particular, local melting rates can be determined, thereby allowing for estimation of the flow inside the tank.

[0016] For example, it has been confirmed that batch coating topography can predict the flow within the molten glass located beneath it. While such flow cannot be directly measured during the operation of the molten tank, it plays a significant role in the energy efficiency of the tank, the wear of the tank components, and the quality of the glass.

[0017] For example, high-temperature glass flow can cause locally different melting rates, or gas formation during the melting process can lead to the formation of "volcanoes," i.e., the outflow of gases released from the molten material. Such effects can worsen the energy efficiency of the tank, affect the glass flow, and in turn, potentially lead to rapid short circuits and, consequently, poor glass quality.

[0018] Knowing the batch coverage topography allows batch feed amounts to be adapted spatially and temporally to these processes, thereby influencing them. For example, the following is possible: - In regions with higher melting rates, a higher feed rate can be set, and in regions with lower melting rates, a lower feed rate can be set. -The selective microwave heating section allows for the desired additional modification of the batch in the glass molten material in regions with lower melting rates. In regions with increased or high melting rates, the selective microwave heating can be reduced, or the microwave heating section can be switched off completely. -A predetermined thickness pattern (which is not uniform everywhere) can be maintained constant over time. For example, a hexagonal pattern can be set for thin batch coating areas, with spacings optimized for the glass viscosity and evaporation rate, and allowing released gases to flow out of the molten material. -Here, the optimal batch thickness topography found can be kept constant over time.

[0019] Within the framework of this invention, it has been confirmed that, for a stable process, in addition to the spatially defined thickness of the batch thickness, it is also important that the defined local thickness of the batch coating remains constant over time.

[0020] Thus, what is specified by the method according to the present invention is, in particular in an all-electric cold-top melting tank, to detect data on the overall batch coating and / or the glass level and / or the glass melt non-contact. The required data is evaluated to create a topographic map of the batch coating and preferably a global topographic map and / or an optimal topography. Data or topographic maps are detected at regular time intervals during the operation of the tank, the temporal change of the topography is evaluated, and a global topography is created. Furthermore, the topography of the batch coating that is optimal for each melting process is determined and this topography is used to control the local feed rate.

[0021] A cold-top melting tank is understood to be a continuously operating melting tank for glass, in which, during operation, the batch is not heated from the upper furnace of the tank. What this means is that the batch is not heated by a burner or other heat source acting on the batch from above on the melt. However, optionally, by means of the microwave heating unit (190), the batch on the melt can be locally assisted during melting and reformed into the glass melt. However, the emission of the microwave output is carried out "from below", i.e., in the boundary layer between the batch and the glass melt, rather than "from above", i.e., in the boundary layer between the batch and the air / gas.

[0022] A schematic cross-section of such a cold-top melting tank 100 is shown in FIGS. 1 and 4. The energy for melting the batch 150 and heating the glass melt 180 is introduced into the glass melt 180 only by the electrodes 110 in FIG. 1. The energy for melting the batch 150 and heating the glass melt 180 is introduced into the glass melt 180 by the electrodes 110 and the microwave heating unit 190 in FIG. 4.

[0023] The batch 130 to be fed is applied to the surface of the glass melt 140 via the arm 120 of the feeding machine. In order to efficiently utilize the introduced heat, the batches fed to the surface of the glass melt 140 form a continuous batch lag 150. The arm 120 of the feeding machine can move substantially over the entire surface of the glass melt 140, as shown, for example, in FIG. 2, and add the batch 130 to be fed to the surface of the glass melt 140 or to an existing batch coating 150.

[0024] At least at the end of the arm 120 of the feeding machine, at least one sensor 160 for non-contact measurement of the batch coating and / or the glass level is attached.

[0025] For this purpose, at least one sensor for detecting point data can be used, and such a sensor for detecting point data can be selected from the group consisting of a radar sensor, an ultrasonic sensor, a laser triangulation sensor, a laser (time-of-flight sensor), or a combination thereof. The punctiform measurement values obtained by such sensors can be used directly to create a topographic map.

[0026] Furthermore, in addition to or instead of one or more point sensors, it is possible to use at least one sensor for detecting the distance between surfaces. Such a sensor for detecting a surface can be selected from the group consisting of, for example, a laser scanner, a 3D camera (time-of-flight, LIDAR), laser triangulation with a line pattern, an IR camera, a photogrammetric sensor, or a combination thereof. The obtained surface data can be used to create a topographic map directly or by joining overlapping partial surface data.

[0027] A combination of at least one sensor for detecting point data and at least one sensor for detecting surface data can also be used, and the obtained data can be used to create a topographic map.

[0028] According to one embodiment of the present invention, one or more sensors may be housed in a water-cooled and / or air-cooled housing.

[0029] Sensor data can be detected during the batch feeding process. Alternatively or additionally, the arm 120 may move across the surface of the glass molten material 180 to record measurement data only by a sensor 160 attached to the end of the arm 120, for example, without feeding a batch.

[0030] The obtained measurement data is processed along with the position of each arm 120 to preferably create a batch coating topography (see Figure 3). Such topography is identified at regular intervals, and changes in the topography are used to identify the optimal batch coating topography. During operation, each identified topography is compared to a designated optimal batch coating topography, and the optimal batch feed amount for each position is identified and added. Furthermore, deviations in the growth of the batch coating topography can be used to identify problems in the process control of the melting tank at an early stage.

[0031] According to one embodiment of the present invention, at least one microwave heating section can be prepared. This at least one microwave heating section can generate energy in the form of a microwave beam, and the generated microwave beam captures at least a portion of the transition area between the batch and the crude molten material (Rauschmelze). Crude molten material is a technical term in glass technology and refers to the molten material before refining. It is the initial molten liquid phase in which all the raw materials have transitioned to a liquid state, but still contains bubbles.

[0032] The microwave beam is coupled to the upper region immediately below the batch coating, and therefore to the melting reaction zone, where the temperature is increased, accelerating melting, in particular, compared to, or even more than, a similar method that does not use a microwave beam. The advantage of this is that the batch coating can be reduced locally and as intended, especially in the lower temperature zone where the batch coating does not melt so rapidly, or in the zone where more batches are added.

[0033] Preferably, at least one microwave heating element is mounted on at least one end of the arm 120 of the feed machine into which the batch of molten glass is added. This allows at least one microwave heating element to be moved across the entire surface of the batch coating, thereby enabling efficient and intended irradiation of localized areas.

[0034] According to one preferred embodiment, a microwave heating unit generates a microwave beam at a frequency higher than 500 MHz and lower than 6 GHz, particularly lower than 3 GHz, preferably 2.45 GHz or less, or 915 MHz or less. The microwave heating unit and batch melting by the microwave beam are known to those skilled in the art, for example, from International Publication No. 2021 / 175506.

[0035] The present invention further relates to the use of a specific method according to the present invention for controlling batch equipment in a glass manufacturing method.

[0036] The present invention further relates to the use of a specific method according to the present invention for controlling at least one microwave heating section in a glass manufacturing method.

[0037] For example, it is possible to avoid locally different melting rates and "volcano" formation caused by glass flow in high-temperature glass and gas formation during the melting process, and to improve the energy efficiency of the tank.

[0038] Furthermore, by controlling the localized thickness of the batch coating, it is possible to influence the glass flow and avoid short-circuit paths in the molten glass, thereby improving glass quality.

[0039] Furthermore, the data detected and processed by the method according to the present invention can be used in combination with artificial intelligence to detect anomalies in the melting process, for example. Thus, it is possible to identify abnormal conditions, and even critical conditions, in the molten glass, and to warn of these conditions early before they occur in the process. [Explanation of symbols]

[0040] 100 Cold Top Melting Tanks 110 electrodes 120 Batch Feeder 130 Batch feeder on conveyor belt 140 Surface of molten glass 150 batch coating 160 sensors 170 Discharge section 180 Molten glass 190 Microwave heating section

Claims

1. A method for detecting and evaluating data on batch coating in an all-electric cold-top melting tank for melting glass, and optionally on the molten glass and optionally on the glass level, The steps include: preparing at least one sensor (160) for non-contact detection of data about the batch coating (150) at at least the end of the arm (120) of a feed machine into which the batch is added to the molten glass; (a) During the operation of the melting tank (100), data about the batch covering (150) is repeatedly detected and stored by at least one of the sensors (160), and (2) data is detected at least 10 different positions on the batch covering, preferably at least 100 different positions, and the data is associated with the positions of the ends of the arm (120) or the sensor (160), respectively. The steps include processing the detected data to create a topographic map of the batch covering (150), preferably a global topographic map and / or preferably an optimal topography, A method of having.

2. The method according to claim 1, wherein at least one sensor (160) is used to detect point data, the sensor (160) is selected from a group consisting of radar, ultrasound, laser triangulation, laser (time-of-flight, LiDAR), or a combination thereof, and / or the obtained point measurements are directly used to create the topographic map.

3. The method according to claim 1, wherein a sensor (160) is used to detect a surface, the sensor (160) is selected from a group consisting of a laser scanner, a 3D camera (time-of-flight, LiDAR), laser triangulation by line pattern, an IR camera, photogrammetry, or a combination thereof, and / or the obtained surface data is used to create the topography map, either directly or by stitching together overlapping partial surface data.

4. The method according to any one of claims 1 to 3, using at least one sensor for detecting point data and a sensor for detecting surface data, and using the data to create the topography map.

5. The method according to any one of claims 1 to 4, wherein the data is detected during the batch feed process and / or simultaneously without performing a batch feed.

6. Furthermore, the method according to any one of claims 1 to 5, wherein data on the glass level and / or data on the molten glass are detected and processed.

7. The method according to any one of claims 1 to 6, wherein one or more sensors are housed in a water-cooled and / or air-cooled housing.

8. The method according to any one of claims 1 to 7, wherein at least one microwave heating section is prepared.

9. The method according to claim 8, wherein at least one microwave heating unit is attached to at least one end of the arm (120) of a feed machine to which the batch is added to the molten glass.

10. Use of a specific method according to any one of claims 1 to 9 for controlling batch equipment in a glass manufacturing method.

11. Use of a specific method according to any one of claims 1 to 9 for controlling at least one of the microwave heating sections in a method for manufacturing glass.

12. The use according to claim 10 or 11, which allows for setting locally smaller batch thicknesses and / or larger batch thicknesses.

13. The use according to claim 10, 11, or 12, which involves setting the optimal topography of the batch coating as determined by the method according to any one of claims 1 to 9.

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