Immersion tube cooling and method for operating an immersion tube cooling

Abstract

The invention relates to a dip tube cooling system (1) and a method for operating a dip tube cooling system (1) for lowering the casting temperature of a melt (A) in continuous casting plants, comprising a container (3) which at least partially encloses an unclaimed dip tube (2) in the axial direction, wherein a channel (4) is formed between the container (3) and the dip tube (2), wherein the container (3) is provided at a first end with a fluid inlet (3.1) and at a second end with a fluid outlet (3.2) for cooling the melt (A) conveyed in the dip tube (2).

Description

Area:

[0001] The present invention relates to an immersion tube cooling system and a method for operating an immersion tube cooling system with high throughputs or casting speeds, thin dimensions and / or in casting and rolling plants. State of the art:

[0002] In certain continuous casting plants, such as those with large ladles, the necessary superheating of the melt causes the melt to enter the mold too hot during pouring. Toward the end of casting, the surface-to-volume ratio of the melt in the ladle increases in favor of the surface area. This leads to accelerated cooling of the melt. As the melt level in the ladle decreases, the temperature of the melt approaches the ideal casting temperature.

[0003] In the following, the term melt essentially defines steel melts, whereby both the method and the device are also fundamentally suitable for lowering the casting temperature of non-ferrous metal melts.

[0004] From the prior art, immersion tube cooling systems and methods for operating immersion tube cooling systems are known, the function of which is to lower the casting temperature of the melts in order to have a desired degree of solid content, e.g. nuclei for crystallization during solidification, in the melt before the melt is filled into the mold.

[0005] For example, WO 2011 / 117296 A1 discloses a method for casting a melt and a suitable dip tube for a continuous casting plant. The aim of WO 2022 / 117296 A1 is to create a method and a dip tube that can produce a cast product with a homogeneous, fine microstructure and a low degree of segregation.

[0006] To do this, the melt flowing from a ladle is cooled in the immersion tube so that the melt has the desired solids content upon exiting the immersion tube. The melt is cooled using heat pipes or a thermosiphon connected to the immersion tube.

[0007] A distinction is made between two types of heat pipes: the heat pipe and the two-phase thermosiphon. The basic operating principle is the same for both designs. The return transport of the fluid occurs passively in both designs, thus requiring no auxiliary means such as a circulation pump. Heat pipes or thermosiphons typically consist of hermetically sealed tubes or another closed structure.

[0008] A first end of the dip tube is in contact with the heat source, causing the liquid fluid in contact with the outer wall of the dip tube to evaporate. The vapor flows through the dip tube to the second end of the dip tube, either vertically inclined at an acute angle or by utilizing the capillary effect, transported back to the end in contact with the heat source.

[0009] A disadvantage of the immersion tube cooling proposed in WO 2011 / 117296 A1, however, is that the use of heat pipes or a thermosiphon is complex and these only cool a small surface of the immersion tube. Consequently, efficient cooling is only possible with a limited volume flow of melt. To achieve surface cooling of the immersion tube, a large number of heat pipes or thermosiphons are necessary. Another disadvantage is that adjusting the dissipated heat is hardly possible or impossible, and cooling occurs passively. Consequently, the method and device do not allow the melt at the outlet of the immersion tube to a specific and constant temperature, while the temperature of the melt at the inlet of the immersion tube changes. Furthermore, the device can only be operated with a liquid coolant. Object of the invention:

[0010] Based on this, the present invention is based on the object of reducing the high temperature of the melt prevailing at the start of casting as quickly as possible by simply cooling the immersion tube with gas or water, and of achieving a constant temperature of the melt during the pouring process into the mold. Furthermore, a user-friendly and structurally simple immersion tube cooling system is to be created. Invention:

[0011] The problem is solved by the features of independent claim 1 and the subordinate claims 14, 15, and 16. Further advantageous embodiments of the invention are presented in the dependent claims. The features listed individually in the dependent claims can be combined with one another in a technologically expedient manner and can define further embodiments of the invention.

[0012] The immersion tube cooling system according to the invention for lowering the casting temperature of a melt in continuous casting plants comprises a container which at least partially encloses an unstressed immersion tube in the axial direction, wherein a channel is formed between the container and the immersion tube, wherein the container is formed at a first end with a fluid inlet and at a second end with a fluid outlet for cooling the melt conveyed in the immersion tube.

[0013] The numerical terms used below ("first", "second", ...) primarily serve (only) to distinguish between multiple similar objects, quantities, or processes and, in particular, do not necessarily specify a dependency and / or sequence of these objects, quantities, or processes. Should a dependency and / or sequence be required, this is explicitly stated here or will be obvious to the person skilled in the art upon studying the specifically described embodiment.

[0014] The invention offers the advantage over the prior art that a large amount of heat can be dissipated through the large-area cooling provided by the container surrounding the immersion tube and through which the fluid flows. As a result, the volume flow of the melt and thus the casting speed can be increased. Furthermore, the invention offers the advantage that the proposed immersion tube cooling system creates a structurally simple device.

[0015] Advantageous embodiments of the immersion tube cooling are shown in the dependent claims 2 to 13.

[0016] Preferably, the container is formed from at least two interconnected shells. The at least two shells are defined such that they each surround the dip tube in sections in the circumferential direction. When viewed together, the two shells surround the dip tube 360°, whereby the respective circumferential section of the shells can be greater or less than 180°. Furthermore, a division into more than two shells is also conceivable, which, in combination, also completely surround the dip tube in the circumferential direction.

[0017] Preferably, at least one of the shells is made of aluminum or an aluminum alloy. Aluminum and its alloys are good thermal conductors, so that heat energy can be transferred from the fluid to the metal, and in turn from the metal to the outside air, via the outer surface of the immersion tube cooling system. The use of aluminum or another metal with good thermal conductivity thus increases the cooling performance of the immersion tube cooling system. It is essential that the dimensions of the shells and the fluid quantities are adapted to the respective casting conditions in order to achieve the best possible cooling.

[0018] In an alternative embodiment of the container to the shells, the container is designed as a cooling sleeve. The second embodiment of the container differs from the embodiment of the container comprising at least two shells in that the immersion tube cooling is formed by a tubular cooling sleeve, which also surrounds the immersion tube and forms a channel between it and the immersion tube. Like the shells, the cooling sleeve itself is made of a material with good heat conduction, such as aluminum or an aluminum alloy, or a copper alloy.

[0019] According to the second embodiment, the container formed from the cooling sleeve is airtight and / or liquid-tight at both of its axial ends, with the container having the fluid inlet at one end and the fluid outlet at the opposite end. In other words, the container according to the second embodiment is completely closed, but has a fluid inlet at one end, when viewed in the axial direction, starting from the flow direction of the dip tube, and a fluid outlet at an opposite end. The fluid inlet and fluid outlet can also be arranged differently on the container in a physically more favorable position relative to one another. Since the cooling sleeve is closed at both axial ends, a clamping device is not necessary, as it is arranged on the dip tube via the closed ends.

[0020] Depending on the fluid, it should be noted that a fluid can partially evaporate during the cooling process within the immersion tube cooling system. In order to keep the gas volume fraction in the channel formed by the space between the immersion tube and the container partially enclosing it as low as possible and thus maintain a constant cooling performance, it is technically advantageous if the fluid inlet is located as far down as possible into the immersion tube cooling system and the fluid outlet is located as high up as possible from the immersion tube cooling system. This arrangement of the fluid inlet and outlet ensures that the resulting gas phase is continuously removed within the immersion tube cooling system. With gas cooling, phase formation is not to be expected, so that from a physical point of view, several options are available for the arrangement of the fluid inlet and outlet.

[0021] Preferably, a turbulence generator is arranged radially inside one of the shells. The turbulence generator creates turbulence in the fluid flowing through the container and along the dip tube. This turbulence provides an increased cooling effect and thus increases the efficiency of the dip tube cooling.

[0022] Preferably, two adjacent shells have a hinge in the region of a first contact area and a positive or non-positive connection option, preferably a screw connection, for connecting the adjacent shells in the region of a second contact area. The positive or non-positive connection option, in particular in the form of a screw connection, is not limited to two shells. The hinge connects the shells to one another in a hinged manner and can thus be subsequently arranged around an immersion tube. To simplify subsequent installation or disassembly in the event of a changed manufacturing process, the screw connections preferably have a wing nut. The screw connection in the form of wing nuts offers the advantage over a conventional nut-screw connection that no tools are required to install the immersion tube cooling system on the immersion tube.This speeds up installation and removal. The torque applied manually to the wing nuts is sufficient to ensure a permanent attachment of the immersion tube cooling system to the immersion tube.

[0023] Preferably, the shells each have a radially inwardly directed clamping device with which they rest against the outer surface of the dip tube when installed. Furthermore, the clamping devices are preferably arranged in the axial direction at the respective ends of the shells for preferably form-fitting fixing of the shells to the dip tube. When the wing nuts are tightened, the shells are pressed or clamped against the dip tube by the clamping device so that the shells sit firmly on the outer surface of the dip tube. Slipping of the shells along the dip tube is thus impossible. Since the dip tube heats up considerably due to the melt flowing through it, the clamping devices are preferably made of a high-temperature-resistant material.

[0024] The fluid is a gas or a liquid. The gas can be air or nitrogen, for example, while the liquid can be water or a specific coolant. A combination of a liquid and a gas is also conceivable.

[0025] To prevent the gaseous and / or liquid fluid from accidentally escaping from the container, the shells are preferably designed to be airtight and / or liquid-tight in their contact areas on the hinge side and in their contact areas on the screw connection side.

[0026] Preferably, the container formed from the shells is airtight and / or liquidtight at one end and open at another end when viewed in the axial direction. Particularly preferably, the container has the fluid inlet at its airtight and / or liquidtight end, with the other open end of the container preferably being designed as a fluid outlet. In other words, the container is bucket-shaped, with the fluid inlet at the level of the bucket bottom. The opening of the bucket, however, represents the fluid outlet. Alternatively or additionally, further openings can also be arranged in the end of the container facing away from the fluid inlet.

[0027] The container and / or the immersion tube are preferably tubular in the axial direction, with the container and the immersion tube preferably being arranged coaxially with each other. To achieve constant and even use of the fluid in the cooling system, the container and / or the immersion tube are tubular in the axial direction and arranged coaxially with each other. A coaxial arrangement of the container in the form of the shells or the cooling sleeve relative to the immersion tube leads to constant cooling of the outer surface of the immersion tube and thus avoids stresses in the immersion tube.

[0028] The immersion tube cooling system preferably comprises a sensor and / or a control system that regulates the fluid flow rate based on the measured volume flow and the melt temperature. The amount of gas or liquid flowing through the channel between the immersion tube and the container is adjusted to the current casting situation. The channel preferably has a clear width of 20 mm to 100 mm, particularly preferably between 30 mm and 80 mm, depending on the required fluid flow rate and the available pump or blower.

[0029] A sensor system according to the invention can measure the required values ​​directly or derive them indirectly from other measured values ​​using suitable process models. Process models can be statistical, analytical, or self-learning, for example.

[0030] The sensors will accordingly determine the volume flow, e.g. measured by magnetic-inductive methods, as well as the temperature of the melt and from this determine the required cooling. The fluid quantity is constantly adjusted as a function of the currently measured casting parameters such as volume flow and temperature of the melt. As an alternative to the volume flow of the melt, the mass flow of the melt is also conceivable as a further or alternative casting parameter. The average flow velocities of the melt in the dip tube are preferably between 0.1 m / s and 1 m / s, further preferably between 0.3 m / s and 0.7 m / s and particularly preferably around 0.5 m / s. The aim is a maximum cooling of the melt of around 15 K, depending on the geometry of the dip tube, the casting performance, the amount of fluid and its temperature. A turbulent flow of the fluid around or along the dip tube is preferred.

[0031] As an alternative to measuring the melt temperature and flow rate, the fluid flow rate is adjusted using a predefined cooling strategy with setpoints. Such a fluid flow rate adjustment is interpolated from previous tests or known empirical values ​​and, if necessary, extrapolated. Measurement of the melt flow rate and temperature is then no longer necessary.

[0032] The melt will have its highest temperature at the beginning of the casting process. Thus, at the beginning of the casting process, i.e. when the ladle is completely full, the melt entering the dip tube is cooled to its maximum by the dip tube cooling system in order to achieve the desired lower melt temperature. As the casting process progresses, the melt cools slightly even before entering the dip tube. Thus, in order to achieve a constant melt temperature as it exits the dip tube and to establish a globular structure, the cooling capacity of the dip tube cooling system is reduced by the amount of melt cooling. To save energy costs, it is advantageous to select the melt temperature at the beginning so that cooling of the melt is no longer necessary at the end of the casting process in order to achieve a homogeneous temperature of the melt flowing into a mold throughout the entire casting process.

[0033] Furthermore, the invention discloses a system comprising a dip tube and a dip tube cooling system according to one of claims 1 to 13, for lowering the casting temperature of a melt flowing through the dip tube, wherein Heat can be transferred from the immersion tube to a fluid flowing through the container; and the quantity of fluid flowing through the container can be regulated or controlled depending on the heat to be dissipated by the immersion tube; and the outer surface of the immersion tube has a surface enlargement that differs from a round diameter, preferably by ribs.

[0034] Increasing the surface area of ​​the immersion tube leads to increased convection between the outer surface of the immersion tube and the fluid being used. A ribbed outer surface of the immersion tube is particularly suitable for this purpose. The ribs extend in the axial direction and thus ensure an increase in the surface-to-volume ratio. However, increasing the surface area of ​​the immersion tube is not limited to ribs. Other design options are also conceivable that lead to a larger surface-to-volume ratio and thus to increased heat transfer from the immersion tube to the fluid.

[0035] To achieve optimal cooling of the immersion tube with the immersion tube cooling system, the immersion tube has a length between 800 mm and 2000 mm, particularly preferably between 900 mm and 1400 mm. The average inner diameter of the immersion tube is preferably between 30 mm and 100 mm, with the inner diameter particularly preferably being between 50 mm and 90 mm. The outer diameter is preferably between 80 mm and 180 mm, and particularly preferably between 90 mm and 130 mm.

[0036] The material of the immersion tube should be optimized for thermal conduction and the stresses arising from the temperature gradient. An Al2O3-based ceramic matrix with an Al2O3 content of > 75% to 85% (wt%) is advantageous. The remainder is made up of oxides or nitrides of boron, zirconium, and / or silicon, as well as unavoidable impurities.

[0037] In addition to the device, the invention also comprises a method according to the invention for operating a dip tube cooling system for lowering the casting temperature of the melt in continuous casting plants according to one of claims 1 to 14, in which the following steps are carried out: a. Introducing the fluid into the vessel via the fluid inlet and allowing the fluid to flow through the vessel; b. Cooling the immersion tube through which the melt flows by means of the fluid introduced and flowing along the outer wall of the immersion tube; c. Discharging the heated fluid from the vessel via the fluid outlet; d. Adjusting the fluid flow rate to the current casting situation based on the casting parameters. e. While steps a. to c. are being carried out, the fluid quantity is adjusted to the current casting situation based on the casting parameters.

[0038] To ensure consistent quality in continuous casting, it is first necessary to keep the temperature of the melt constant during pouring into the mold. In certain continuous casting plants, for example, those with large ladles, the necessary superheating of the melt causes the melt to enter the mold too hot during pouring. As the melt level in the ladle decreases, the temperature of the melt approaches the ideal casting temperature. Towards the end of the casting, the surface-to-volume ratio of the melt increases, favoring the surface area.

[0039] Preferably, the casting parameters are determined continuously from the volume flow and the temperature of the melt, wherein the volume flow of the fluid is preferably reduced, preferably proportionally, as the volume flow and the temperature of the melt decrease.

[0040] By measuring and / or controlling the volume flow and temperature of the melt and the associated regulated and / or controlled cooling of the melt, a homogeneous temperature of the melt can be achieved during the pouring process into the mold. Accordingly, the amount of fluid is proportionally reduced using variable casting parameters, according to step d. Alternatively, the required cooling flow is preferably set in advance and without measurement, with maximum cooling of the immersion tube by the fluid then preferably occurring at the start of casting, medium cooling of the immersion tube by the fluid towards the middle of casting, and no cooling of the immersion tube by the fluid at the end of casting.

[0041] Preferably, the fluid is cooled in an unused heat exchanger downstream of the fluid outlet and, after cooling, fed back into the vessel via the fluid inlet. Alternatively, fresh fluid is preferably used to cool the immersion tube. A closed cooling circuit is preferable for cooling by liquid, whereas an open cooling circuit is preferable for cooling by air, for example. However, a closed cooling circuit is also possible when using nitrogen or other gases, including air.

[0042] The following six figures are attached to the description: Fig. 1: Schematic representation of an immersion tube cooling system Fig. 2: Schematic cross-sectional view of the immersion tube cooling system Fig. 3: Schematic cross-sectional view of an immersion tube cooling system according to a second embodiment Fig. 4: Schematic representation of the immersion tube cooling system according to the second embodiment

[0043] The invention is described in detail below with reference to the figures mentioned in the form of exemplary embodiments. In all figures, identical technical elements are designated by identical reference numerals.

[0044] Fig. 1 shows a schematic representation of an immersion tube cooling system 1 according to the invention for lowering the casting temperature of melt A in continuous casting plants with high throughputs or casting speeds, thin dimensions, or in continuous casting-rolling plants. The immersion tube cooling system 1 is formed from two shells 3.3, each with a circumference of 180°. The shells 3.3 themselves are made of a material with good heat conductivity, such as aluminum (Al) or an aluminum alloy.

[0045] According to Fig. 2The shells 3.3 are provided with a hinge 3.6 on their mutually contacting longitudinal contact surfaces on a first side and with screw connections 3.7 on the parallel and opposite second side. The hinge 3.6 connects the shells 3.3 to one another in a hinged manner, allowing them to be subsequently arranged around an immersion tube 2. To simplify subsequent installation or disassembly in the event of a change in the manufacturing process, the screw connections 3.7 are designed as wing nuts.

[0046] Immersion tubes 2 typically consist of a refractory mix of aluminum oxide (Al 2 O 3 ), silicon oxide (SiO 2 ), zirconium dioxide (ZrO 2 ), potassium oxide (CaO), magnesium oxide (MgO), and carbon (C). To increase the heat transfer from the melt A to the fluid B or to the gas, a refractory material with higher thermal conductivity can be deliberately selected.

[0047] The two shells 3.3 are each provided with star-shaped clamping devices 5 on their inner sides. The clamping devices 5 are arranged in the axial end regions of the respective shell 3.3, pointing radially inward. When the screw connections 3.7 are tightened, the shells 3.3 are pressed or clamped against the immersion tube 2 by the star-shaped clamping devices 5 made of high-temperature-resistant material, so that the shells 3.3 sit firmly on the immersion tube 2. Slipping of the shells 3.3 is thus impossible. After installation, the shells 3.3 are arranged coaxially around the immersion tube 2 and form a tube themselves. Although not shown in the figures, the shells 3.3 are sealed airtight and / or liquid-tight at the top. Also not shown in the figures, the shells 3.3 are also sealed on all contact surfaces, such as in the area of ​​the screw connection 3.7 and in the area of ​​the hinge 3.6 and in the upper contact area to the immersion tube 2 are also sealed air-tight and / or liquid-tight.

[0048] The immersion tube cooling system 1, formed by the shells 3.3, forms a channel 4 in the form of an annular gap between itself and the immersion tube 2. Channel 4 is designed to be flowed through by a fluid B, which cools the melt A via the outer surface of the immersion tube 2. According to the first embodiment, fluid B is a gas, for example, air or nitrogen. Channel 4 has a clear width of 30 mm - 80 mm, for example, depending on the required gas throughput and available fan.

[0049] In the axially upper region of the immersion tube cooling 1 formed from the shells 3.3, a fluid inlet 3.1 is formed, into which the fluid B is blown in the form of air or gas by a fan (not shown).

[0050] The annular channel 4 formed by the shells 3.3 is flowed through by cold gas B, which is blown in through the fluid inlet 3.1. The aim is to convey as much and as cool as possible through the channel 4. The temperature of the blown-in gas can be, for example, 0 - 20°C. The heated gas can be blown in radially directly below the tundish dip tube connection (not shown) and then flows either coaxially out of the annular channel 4 of the shells 3.3 around the dip tube 2, which then forms a fluid outlet 3.2, or, although not shown, the gas is discharged radially outwards through holes in the walls of the shells 3.3 as further fluid outlets 3.2. Furthermore, additional turbulence generators 3.5 in the channel 4 support the convective heat transport from the dip tube 2 to the surrounding gas.By using gas as coolant, no wear on the outside of the immersion tube 2 is to be expected even at high volume flows.

[0051] To further increase the cooling effect, the surface area of ​​the immersion tube 2 can be enlarged. This can be achieved, for example, by adding additional cooling fins (not shown) to the outer surface of the immersion tube 2. In principle, the cooling effect can be increased by increasing the volume-to-area ratio in favor of the surface area. Under this premise, various geometric designs of the immersion tube 2 and the immersion tube cooling system 1 are conceivable. The shape must generally be adapted to the cooling situation and is limited only by the manufacturing expertise of the refractory supplier.

[0052] Fig. 3shows a schematic cross-sectional view of an immersion tube cooling system 1 according to the invention according to a second embodiment, for lowering the casting temperature of the melt A in continuous casting plants with high throughputs or casting speeds, thin dimensions or in endless casting-rolling plants. The second embodiment differs from the first embodiment in that the immersion tube 2 is cooled with a liquid fluid B. In principle, the structure of the immersion tube cooling system 1 of the second embodiment is very similar to that of the first embodiment. The second embodiment differs from the first embodiment primarily in that the immersion tube cooling system 1 is formed from a tubular cooling sleeve 3.4, which also coaxially surrounds the immersion tube 2.

[0053] The cooling sleeve 3.4 itself consists of a material with good heat conduction, such as aluminum (Al) or an aluminum alloy, which completely encloses the immersion tube 2.

[0054] As in Fig. 4 As shown, the cooling sleeve 3.4 is sealed airtight and / or liquid-tight in the axially upper and lower contact areas with the immersion tube 2. This eliminates the need for clamping devices on the inside of the cooling sleeve 3.4 to hold it coaxially around the immersion tube 2.

[0055] Like the shells 3.3, the cooling sleeve 3.4 and the immersion tube cooling 1 form an annular channel 4 between them. Channel 4 has a clear width of 30 mm - 80 mm, for example, depending on the required fluid flow rate and available pump.

[0056] A fluid inlet 3.1 is formed in the axially upper region of the immersion tube cooling system 1 formed by the cooling sleeve 3.4. The liquid fluid B flows through the annular channel 4 formed by the cooling sleeve 3.4 and the immersion tube 2, and is fed to the annular channel 4 through the fluid inlet 3.1. As with the first embodiment, the aim is to convey as much and as cool a fluid B as possible through the annular channel 4. The temperature of the introduced liquid fluid B can be, for example, 5 to 20°C. It should be noted that most liquids have a higher heat capacity than gases, which means that a liquid-operated immersion tube cooling system 1 can be smaller than a gas-operated immersion tube cooling system 1 while maintaining the same cooling capacity.

[0057] The fresh liquid fluid B can be pumped radially into the annular channel 4 via the fluid inlet 3.1 directly below the tundish immersion tube connection, which is located at a first end of the immersion tube cooling system 1. At the second end of the immersion tube cooling system 1, the fluid B exits the immersion tube cooling system 1 through the fluid outlet 3.2 and is fed, for example, to a heat exchanger (not shown). After passing through the heat exchanger, the cooled fluid B is made available again to the immersion tube cooling system 1 via the fluid inlet 3.1 by means of the pump (not shown).

[0058] Depending on the choice of liquid B, it should be noted that liquids can partially evaporate during the cooling process within the immersion tube cooling system 1. In order to keep the gas volume fraction in the annular channel 4 as low as possible and thus maintain a constant cooling performance, it is technically advantageous if the fluid inlet 3.1 is located as far down as possible into the immersion tube cooling system 1 and the fluid outlet 3.2 is located as far up as possible from the immersion tube cooling system 1. This arrangement of the fluid inlet 3.1 and the fluid outlet 3.2 ensures continuous removal of the resulting gas phase within the immersion tube cooling system 1.

[0059] Even in the second embodiment, although not shown, it is conceivable that additional turbulence generators in the annular channel 4 increase the convective heat transport from the immersion tube 2 to the surrounding, essentially liquid fluid B. Reference symbol Meaning 1 Immersion tube cooling 2 dip tube 3 container 3.1 Fluid inlet 3.2 Fluid outlet 3.3 Peel 3.4 Cooling cuff 3.5 Turbulence generator 3.6 hinge 3.7 screw connection 4 channel 5 clamping device A melt B Fluid

Claims

1. Immersion tube cooling (1) for lowering the casting temperature of a melt (A) in continuous casting plants, comprising a container (3) which at least partially encloses an unstressed immersion tube (2) in the axial direction, - wherein a channel (4) is formed between the container (3) and the immersion tube (2); and - the container (3) is formed at a first end with a fluid inlet (3.1) and at a second end with a fluid outlet (3.2) for cooling the immersion tube (2) and thus the melt (A) conveyed in the immersion tube (2).

2. Immersion tube cooling (1) according to claim 1, characterized in that the container (3) is formed from at least two interconnected shells (3.3).

3. Immersion tube cooling (1) according to claim 2, characterized in that at least one of the shells (3.3) is made of aluminum or an aluminum alloy.

4. Immersion tube cooling (1) according to one of the preceding claims, characterized in thata turbulence generator (3.5) is arranged radially on the inside of at least one of the shells (3.3).

5. Immersion tube cooling (1) according to one of the preceding claims, characterized in that - two adjacent shells (3.3) have a hinge (3.6) in the region of a first contact area; and - the shells (1.2) have a positive or non-positive connection option, preferably a screw connection (3.7), for connecting adjacent shells in the region of a second contact area.

6. Immersion tube cooling (1) according to claim 5, characterized in that the screw connection (3.7) has a wing nut.

7. Immersion tube cooling (1) according to one of the preceding claims, characterized in that the shells (3.3) each have a radially inwardly directed clamping device (5) with which they rest, preferably in a form-fitting manner, on the outer surface of the immersion tube (2) in the installed state.

8. Immersion tube cooling (1) according to claim 7, characterized in that the clamping devices (5) are arranged in the axial direction at the respective ends of the shells (3.3) for fixing the shells (3.3) to the immersion tube (2), preferably in a form-fitting manner.

9. Immersion tube cooling (1) according to one of claims 7 or 8, characterized in that the clamping devices (5) are made of a high-temperature-resistant material.

10. Immersion tube cooling (1) according to one of claims 5 to 9, characterized in that the shells (3.3) are designed to be air-tight and / or liquid-tight in their contact areas on the hinge side (3.6) and in their contact areas on the screw connection side (3.7).

11. Immersion tube cooling (1) according to one of claims 2 to 10, characterized in that - the container (3) formed from the shells (3.3) is airtight and / or liquid-tight at one end when viewed in the axial direction; and - the container (3) is open at another end.

12. Immersion tube cooling (1) according to claim 11, characterized in that - the container (3) has the fluid inlet (3.1) at its air-tight and / or liquid-tight end; and - the other open end of the container (3) is designed as a fluid outlet (3.2).

13. Immersion tube cooling (1) according to one of the preceding claims, characterized in that - the container (3) and / or the dip tube (2) are tubular in the axial direction; and - the container and the dip tube are arranged coaxially to one another.

14. System comprising an immersion tube (2) and an immersion tube cooling system (1) according to one of claims 1 to 13, for lowering the casting temperature of a melt (A) flowing through the immersion tube and a control or regulating device for the mass flow of the fluid (B), wherein - heat can be transferred from the immersion tube (2) to a fluid (B) flowing through the container (3); and - the quantity of fluid (B) flowing through the container can be regulated or controlled depending on the heat to be dissipated by the immersion tube; and - the outer surface of the immersion tube (2) has an enlarged surface area which differs from a round diameter, preferably by means of ribs.

15. System comprising an immersion tube (2) and an immersion tube cooling system (1) according to one of claims 1 to 13 and a continuous casting plant for lowering the casting temperature of a melt (A) flowing through the immersion tube and a control or regulating device for the mass flow of the fluid (B), wherein - heat can be transferred from the immersion tube (2) to a fluid (B) flowing through the container (3); and - the quantity of fluid (B) flowing through the container can be regulated or controlled depending on the heat to be dissipated by the immersion tube; and - the outer surface of the immersion tube (2) has an enlarged surface area which differs from a round diameter, preferably by means of ribs.

16. A method for operating a dip tube cooling system (1) for lowering the casting temperature of the melt (A) in continuous casting plants according to one of claims 1 to 14, in which the following steps are carried out: a) introducing the fluid (B) into the container (3) via the fluid inlet (3.1) and allowing the fluid (B) to flow through the container (3); b) cooling the dip tube (2) through which the melt (A) flows by the fluid (B) introduced and flowing along the outer wall of the dip tube (2); c) discharging the heated fluid (B) from the container (3) via the fluid outlet (3.2); d) adapting the volume flow of the fluid to the current casting situation based on the casting parameters 17. Method according to claim 16, characterized in that - the casting parameters are continuously determined from the volume flow and the temperature of the melt (A); and - as the volume flow and the temperature of the melt (A) decrease, the volume flow of the fluid (B) is reduced, preferably proportionally.

18. Method according to claim 17, characterized in that - at the start of casting, maximum cooling of the immersion tube (2) by the fluid (B) takes place, with medium cooling of the immersion tube (2) by the fluid (B) taking place towards the middle of casting; and - at the end of casting, no cooling of the immersion tube (2) by the fluid (B) takes place.

19. Method according to one of claims 16 to 18, characterized in that the fluid (B) is cooled in an unused heat exchanger downstream of the fluid outlet (3.2) and, after cooling, is fed back to the container (3) via the fluid inlet (3.1).

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