System, furnace snout therefor and snout mouthpiece for said furnace snout

Abstract

A system (1), in particular a hot-dip galvanizing system for metal sheet or strip (S), a furnace snout (4) therefor, and a snout mouthpiece (6) for the furnace snout (4), which connects the furnace (2) to a molten metal bath (3), in particular a zinc alloy bath, are disclosed, wherein the snout mouthpiece (6) is configured for immersion into the molten metal bath (3). In order to enable easy handling with long service lives, it is proposed that the snout mouthpiece (6) is configured for releasably connecting to a snout main body (5) of the furnace snout (4).

Description

[0001] The system, the furnace nozzle for it, and the nozzle mouthpiece for this furnace nozzle.

[0002] Technical field

[0003] The invention relates to a plant, in particular a hot-dip galvanizing plant for sheet metal or strip metal, a furnace nozzle for this purpose and a nozzle mouthpiece for this furnace nozzle for connecting the furnace to a molten metal bath, in particular a zinc alloy bath, wherein the nozzle mouthpiece is designed for immersion in the molten metal bath.

[0004] State of the art

[0005] In hot-dip galvanizing plants, it is common practice to connect a continuous furnace to a zinc alloy bath via a stainless steel furnace nozzle, creating a gas-tight seal. The nozzle of the furnace is immersed in the zinc alloy bath. This nozzle is subjected to high temperatures, chemical corrosion, and mechanical stress, often necessitating replacement of the furnace nozzle.

[0006] Description of the invention

[0007] Therefore, starting from the prior art, the invention aims to create a nozzle mouthpiece that facilitates the maintenance of the oven nozzle while maintaining high stability.

[0008] The invention solves the stated problem by the features of claim 1. By designing the nozzle tip for detachable connection to a main body of the furnace nozzle, the stability of the entire furnace nozzle can be significantly improved. Thus, if necessary, only the tip needs to be replaced, while the main body of the nozzle continues to be used, which noticeably reduces operating costs. Furthermore, this modular design allows for more flexible adaptation of the furnace nozzle to the respective molten metal bath, so that the thermal, chemical, and mechanical stresses during immersion in the melt can be optimally taken into account.

[0009] For example, such increased resistance to extreme thermal stresses of several hundred to over 1500 °C can be achieved. At the same time, resistance to chemical influences, such as corrosion from the molten metal and its flow, can be significantly improved. Mechanical stresses such as abrasion, caused by direct contact with the melt and slag, can also be better managed by selecting a suitable material. Since this material selection is limited to the replaceable nozzle, more expensive materials can be used without significantly increasing the overall costs. Furthermore, maintenance is reduced, as it is primarily limited to replacing the nozzle, which contributes to long-term cost optimization of the entire furnace nozzle.

[0010] For example, the nozzle nozzle has a support body made of a ceramic fiber composite material. This ceramic fiber composite offers high strength and resistance to high temperatures and chemical stresses. Furthermore, this material ensures a uniform distribution of forces and stresses within the support body, which serves as the load-bearing base for the nozzle nozzle, thus improving its stability. For immersion in a molten metal bath, it can be particularly advantageous if the ceramic fiber composite material uses a ceramic matrix selected from the group consisting of Al₂O₃, CaSiO₃, 3Al₂O₃, 2SiO₂ (Nullite), Si₃N₄, SiC, ZrSiO₄, and mixtures thereof. These materials are characterized by high strength, low density, and excellent temperature and wear resistance.

[0011] For example, the use of Al₂O₃ (aluminum oxide) in ceramic fiber composites offers the advantage of exceptionally high hardness and temperature resistance, which can lead to high mechanical strength and resistance to wear and corrosion. In comparison, CaSiO₃ (calcium silicate) is characterized by its comparatively low thermal expansion, which provides shock resistance to surface waves in the molten metal bath. Mixtures of Al₂O₃ and CaSiO₃ combine the mechanical strength and temperature resistance of aluminum oxide with the thermal shock resistance of calcium silicate, which can further improve the stability of the furnace nozzle.

[0012] Preferably, the ceramic fiber composite material comprises fibers selected from the group consisting of Al2O3 fibers, SiO2 fibers, B2O3 fibers, carbon fibers, basalt fibers and mixtures thereof.

[0013] This gives the ceramic fiber composite outstanding advantages in terms of strength, stiffness, and thermal stability. Aluminum oxide (Al₂O₃) fibers ensure high mechanical strength and temperature resistance, while silicon dioxide (SiO₂) provides excellent thermal insulation and chemical resistance. This advantageous thermal insulation is also known from B₂O₃ fibers. Carbon fibers offer, among other things, comparatively high mechanical, thermal, and chemical stability. Basalt fibers are characterized by comparatively high temperature resistance and good resistance to corrosion. Blends of these materials allow for precise tailoring of properties, such as optimized thermal conductivity or improved fracture toughness.Strength, stiffness and thermal stability of the proboscis mouthpiece can be further improved if the fibers are present in the form of a knitted, woven, braided or non-woven fabric, especially arranged in layers on top of each other, in the fiber composite material.

[0014] For example, a ceramic fiber composite material with a ceramic matrix made of CaSiO3 and with fibers made of SiO2 fibers can prove to be particularly resistant to mechanical, thermal and / or chemical stresses.

[0015] For example, the nozzle tip has a boron nitride surface coating, particularly a hexagonal one. This combines the mechanical advantages of a lightweight and stable base material with the chemical stability provided by boron nitride (BN), which can further improve the nozzle tip's suitability for immersion in a melt bath. Furthermore, a hexagonal boron nitride surface coating can reduce surface adhesion, further minimizing build-up on the nozzle tip and thus increasing the furnace nozzle's stability. Preferably, the boron nitride surface coating is applied to the carrier body.

[0016] The nozzle mouthpiece according to the invention is particularly suitable for an oven nozzle.

[0017] Preferably, the nozzle mouthpiece is detachably and floatingly attached to the main body of the nozzle. This attachment can, for example, be inclined, e.g., transversely, to a longitudinal direction of the furnace nozzle.

[0018] This design allows the nozzle tip to move more freely under temperature fluctuations or other stresses, thus increasing the service life of the furnace nozzle. Furthermore, this design can also facilitate a more even distribution of forces and stresses within the furnace nozzle, which can improve the overall performance and durability of the system. It is conceivable that the furnace nozzle incorporates a clamping device that detachably connects the nozzle tip to the main nozzle body. This would, among other things, simplify handling and allow for precise adjustment of the nozzle tip's position on the main nozzle body, ensuring a stable, gas-tight connection between the nozzle tip and the main nozzle body.

[0019] A further improvement in the design of the furnace nozzle can be achieved if the clamping device incorporates a linear guide that supports the nozzle tip in a floating manner along its guide track on the main nozzle body. For example, the linear guide could be a linear sliding guide.

[0020] The floating bearing along the linear guide's track enables a more flexible and / or precise compensating movement, which compensates for tolerances and inaccuracies in alignment. This, for example, reduces stresses within the entire structure more precisely and contributes to a longer service life of the furnace nozzle.

[0021] Preferably, the clamping device includes a spring that supports the nozzle tip on the main nozzle body under spring preload in the longitudinal direction of the furnace nozzle. The spring ensures a constant preload, thereby preventing unwanted play and, among other things, guaranteeing a gas-tight connection between the nozzle tip and the main nozzle body.

[0022] The above can be further improved, for example, by providing at least one clamping device on each outer surface of the furnace nozzle.

[0023] Handling during assembly and maintenance of the furnace nozzle can be further simplified if the clamping device incorporates a toggle clamp, particularly a horizontal one, or a locking clamp. The connection between the nozzle body and the nozzle tip can be improved, for example, if the nozzle body terminates at a flange projecting laterally, to which the nozzle tip connects. This can be advantageous when the nozzle body and nozzle tip undergo differing thermally induced dimensional changes, as it helps to absorb relative movements between them.

[0024] For example, differences in thermal expansion between these two connecting parts can be better compensated for if the main nozzle body has a groove into which the nozzle tip engages with lateral play relative to the groove. This also allows for a more effective minimization of stresses caused by thermal expansion, as the lateral play ensures limited, controlled movement of the nozzle tip within the groove. The functionality of the connection is maintained while simultaneously reducing material fatigue and structural damage caused by temperature fluctuations.

[0025] The gas-tight connection of the nozzle tip to the main nozzle body described above can be reliably ensured if at least one high-temperature seal, in particular a ceramic seal, fiberglass seal, Al2O3 seal and / or graphite seal, is provided between the main nozzle body and the nozzle tip.

[0026] This seal between the main body of the nozzle and the nozzle tip can be further improved if a nitrogen curtain exists between two high-temperature seals.

[0027] The nozzle or furnace nozzle according to the invention is particularly suitable for a plant, especially a hot-dip galvanizing plant for sheet metal or strip, for example made of steel. For this purpose, the plant can, for example, comprise a furnace and a molten metal bath, wherein the furnace nozzle connected to the furnace immerses its nozzle into the molten metal bath. The furnace can, for example, be a continuous furnace. The molten metal bath can, for example, be a zinc alloy bath.

[0028] Brief description of the drawings

[0029] The figures illustrate the invention in more detail using an exemplary embodiment.

[0030] Fig. 1 shows a side view of a hot-dip galvanizing plant with a furnace nozzle and a metal molten bath.

[0031] Fig. 2 shows a front view of the system according to Fig. 1.

[0032] Fig. 3 shows an enlarged sectional view of a detachable connection between a nozzle mouthpiece and a nozzle main body of the furnace nozzle shown in Fig. 1 and

[0033] Fig. 4 shows an enlarged sectional view of the nozzle mouthpiece of the furnace nozzle shown in Fig. 1, immersed in the molten metal bath.

[0034] Method for implementing the invention

[0035] Figures 1 and 2 show part of a plant 1, namely a hot-dip galvanizing plant for a steel strip S. This plant 1 comprises a furnace 2, namely a continuous furnace, a molten metal bath 3, namely a zinc alloy bath, and a furnace nozzle 4. The furnace nozzle 4 connects the furnace 2 to the molten metal bath 3 in a gas-tight manner to prevent atmospheric contact between the steel strip S or sheet.

[0036] The furnace nozzle 4 shown as an example has a multi-part, namely – as shown in Figs. 1 and 2 – two-part main nozzle body 5 made of steel. The two-part main nozzle body 5 shown as an example is divided into a connecting piece 5a and a nozzle channel section 5b, which may be connected to the furnace via a flange piece (not shown in detail).

[0037] In addition, the furnace nozzle 4 has a nozzle mouthpiece 6 which connects to the main nozzle body 5 and immerses in the metal molten bath 3 or is designed to do so.

[0038] The main body of the nozzle 5, which connects to the furnace 2, is often referred to as the upper section of the furnace nozzle 4, as this upper section is located outside the molten metal bath. Accordingly, the nozzle mouthpiece 6, the section of the furnace nozzle 4 that extends into the molten metal bath, is referred to as the lower section.

[0039] The main nozzle body 5 is – in the exemplary embodiment – ​​a hollow body with a preferably rectangular cross-section. The nozzle nozzle 6 is – in the exemplary embodiment – ​​also a hollow body with a preferably rectangular cross-section. The metal strip S or sheet runs inside these hollow bodies.

[0040] The nozzle mouthpiece 6 is detachably connected to the main nozzle body 5 in order to make it easy to replace and to adapt its material to the respective metal melting bath 3.

[0041] For example, the support body 7 of the trunk mouthpiece 6 consists, at least in sections, of a material different from the support of the trunk main body 5.

[0042] In the exemplary embodiment, the support body 7 is made of a ceramic fiber composite material, as can be seen in Fig. 4. This makes the nozzle 6 particularly well suited for immersion in the molten metal bath 3, since the support body 7, as the supporting base of the nozzle 6, offers high strength and resistance to high temperatures and chemical stresses. This is especially true regarding deposits of zinc dust 8a, oxide layers 8b, and other particles 8c.

[0043] It is conceivable that the ceramic fiber composite material has a ceramic matrix selected from the group consisting of Al₂O₃, CaSiO₃, 3Al₂O₃, 2SiO₂ (Nullilite), Si₃N₄, SiC, ZrSiO₄, and mixtures thereof. Al₂O₃ and CaSiO₃ have proven to be particularly robust as ceramic matrices. CaSiO₃ has also proven to be a preferred ceramic matrix for one-piece fabrication. The chamfers for the ceramic fiber composite material could be selected from the group consisting of Al₂O₃ fibers, SiO₂ fibers, B₂O₃ fibers, carbon fibers, basalt fibers, and mixtures thereof, in order to further improve the stability of the nozzle mouthpiece 6. AI2O3 fibers or SiO2 fibers can retain their strength even at high temperatures and are also particularly resistant to chemical stresses, for example to different slags.In particular, SiO2 fibers are distinguished by their high resistance to abrasion and wear, combined with comparatively good compatibility with the ceramic matrix, for example CaSiO3, leading to an increased service life and performance of the furnace nozzle 4. Preferably, the furnace nozzle 4 shown in Figures 1 to 4 comprises a ceramic fiber composite material with a ceramic matrix of CaSiO3 and with fibers made of SiO2 fibers.

[0044] An additional advantage is that these fibers are present in the form of a layered fabric arranged on top of each other in the fiber composite material.

[0045] Furthermore, build-up is further reduced by applying a hexagonal boron nitride surface coating 9 directly to the ceramic fiber composite material of the nozzle tip 6. This coating is applied, for example, to the outer and inner surfaces as well as the free end face of the nozzle tip 6 and / or, for example, at least over the entire surface of those sections of the nozzle tip 6 that are immersed in the molten metal bath 3. In addition, there is a special connection between the nozzle tip 6 and the main nozzle body 5. The nozzle tip 6 is not only detachably but also floatingly attached to the main nozzle body 5. This allows for a certain degree of movement between the main nozzle body 5 and the nozzle tip 6, which prevents stresses at the connection caused by the attachment.This in turn significantly increases the stability of the furnace nozzle 4, especially if, according to the invention, different materials are used for the main nozzle body 5 and the nozzle mouthpiece 6, resulting in different thermal expansions that need to be accommodated.

[0046] It is also advantageous that the furnace nozzle 4 has several clamping devices 10 that detachably connect the nozzle body 5 and the nozzle outlet 6, as can be seen in Figures 1 to 3. This improves the detachable connection and also facilitates the replacement or maintenance of the nozzle outlet 6. The clamping devices 10 are designed as horizontal locking clamps and are provided on all four outer surfaces 4a, 4b, 4c, 4d of the wall of the furnace nozzle 4. Thus, in the exemplary embodiment, there are four clamping devices 10 each on the wide outer surfaces 4a, 4b and one clamping device 10 each on the narrow outer surfaces 4c, 4d. A stable connection between the nozzle body 5 and the nozzle outlet 6 is thereby created.

[0047] Furthermore, the clamping devices 10 are specially designed. These clamping devices 10 feature a linear guide 11, namely a linear sliding guide. In Fig. 3, for example, this linear guide 11 has an undercut guide geometry – in this embodiment, this linear guide 11 is designed as a dovetail guide. Other guide geometries are conceivable, for example, a T-slot guide, etc., which has not been shown.

[0048] The linear guide 11 has a guide rail 11a as the first fixed guide element and a sliding element 11b engaging in this guide rail 11a as the second movable guide element. This allows the linear guide 11 to create a floating connection between the main nozzle body 5 and the nozzle nozzle 6 along the guide path of the linear guide 11.

[0049] Furthermore, the clamping device 10 has a spring 12 which supports the nozzle tip 6 on the main nozzle body 5 under spring preload in the longitudinal direction L of the furnace nozzle 4. The spring 12 ensures a stable positioning of the nozzle tip 6 on the main nozzle body 5, thus guaranteeing a gas-tight connection.

[0050] This also applies to overlap areas resulting from a flange 13 projecting laterally from the main body of the nozzle 5, to which the nozzle mouthpiece 6 is connected.

[0051] The flange 13 also has a groove 14 with two high-temperature seals 15. The nozzle 6, specifically the support body 7, projects into this groove 14 with lateral clearance. The nozzle 6 also bears against these high-temperature seals 15.

[0052] This ensures a particularly stable and gas-tight detachable connection between the main body of the nozzle 5 and the nozzle mouthpiece 6 of the furnace nozzle 4.

[0053] As can be seen in Fig. 3, the second guide element carries a locking element 10a of the clamping device 10, to which a clamping element 10b of the clamping device 10, for example U-shaped, is detachably connected. A clamping lever 10c, which has a handle at its free end and is movably connected to the main body of the nozzle 5 via a pivot bearing 17, serves to pivot the clamping element 10b. The clamping element 10b is pivotably mounted on the clamping lever 10c between the pivot bearing 17 and the handle.

[0054] It is generally accepted that "in particular" can be translated into English as "more particularly". A feature preceded by "in particular" is to be considered an optional feature that can be omitted and therefore does not constitute a limitation, for example, of claims. The same applies to "preferably", which is translated into English as "preferably".

Claims

Patent claims:

1. Nozzle mouthpiece for a furnace nozzle (4) connecting a furnace (2) with a metal melting bath (3), in particular a zinc alloy bath, wherein the nozzle mouthpiece (6) is designed for immersion in the metal melting bath (3), characterized in that the nozzle mouthpiece (6) is designed for detachable connection with a nozzle main body (5) of the furnace nozzle (4).

2. Trunk mouthpiece according to claim 1, characterized in that the trunk mouthpiece (6) has a support body (7) made of a ceramic fiber composite material.

3. Proboscis mouthpiece according to claim 2, characterized in that the ceramic fiber composite material comprises as a ceramic matrix selected from the group consisting of Al2O3, CaSiO3, 3Al2O3 2SiO2 (Nullite), Si3N4, SiC, ZrSiO4 and mixtures thereof, and / or that the ceramic fiber composite material comprises as fibers selected from the group consisting of Al2O3 fibers, SiO2 fibers, B2O3 fibers, carbon fibers, basalt fibers and mixtures thereof.

4. Proboscis mouthpiece according to claim 2 or 3, characterized in that the fibers are present in the form of a knitted, woven, braided or laid fabric in the fiber composite material, in particular arranged in layers one above the other, and / or that the ceramic matrix consists of CaSiO3 and the fibers of SiO2 fibers.

5. Prong nozzle according to one of claims 1 to 4, characterized in that the prong nozzle (6) has a boron nitride surface coating (9), in particular a hexagonal one, which is provided in particular on the carrier body (7).

6. Oven nozzle with a nozzle mouthpiece (6) according to one of claims 1 to 5.

7. Oven nozzle according to claim 6, characterized in that the nozzle mouthpiece (6) is detachably and floatingly attached to the main body (5) of the oven nozzle (4), in particular inclined, for example transversely, to a longitudinal direction (L) of the oven nozzle (4).

8. Oven nozzle according to one of claims 6 to 7, characterized in that the oven nozzle (4) has a clamping device (10) which detachably connects the nozzle mouthpiece (6) with the nozzle main body (5).

9. Oven nozzle according to claim 8, characterized in that the clamping device (10) has a linear guide (11), in particular a linear sliding guide, which supports the nozzle mouthpiece (6) floatingly on the nozzle main body (5) along its guide path.

10. Oven nozzle according to claim 8 or 9, characterized in that the clamping device (10) has a spring (12) which supports the nozzle mouthpiece (6) on the nozzle main body (5) under spring preload in the longitudinal direction (L) of the oven nozzle (4).

11. Oven nozzle according to one of claims 6 to 10, characterized in that at least one clamping device (10) is provided on each outer surface (4a, 4b, 4c, 4d) of the oven nozzle (4).

12. Oven nozzle according to one of claims 11, characterized in that the clamping device (10) has a, in particular horizontal, toggle lever clamp or locking clamp.

13. Oven nozzle according to any one of claims 6 to 12, characterized in that the main nozzle body (5) terminates at a flange (13) projecting laterally from it, to which the nozzle mouthpiece (6) is connected.

14. Oven nozzle according to any one of claims 6 to 13, characterized in that the main nozzle body (5) has a groove (14) into which the nozzle mouthpiece (6) projects with lateral clearance to the groove (14).

15. Oven nozzle according to one of claims 6 to 14, characterized in that at least one high temperature seal (15a, 15b), in particular a ceramic seal, glass fiber seal, Al2O3 seal and / or graphite seal, is provided between the nozzle main body (5) and the nozzle mouthpiece (6).

16. Oven nozzle according to claim 15, characterized in that a nitrogen curtain (16) is provided between two high-temperature seals (15a, 15b) for sealing.

17. Plant, in particular hot-dip galvanizing plant for metal sheet or strip (S), with a nozzle nozzle (6) according to one of claims 1 to 5 or with a furnace nozzle (4) according to one of claims 6 to 16.

18. Plant according to claim 17, characterized in that the plant (1 ) comprises a furnace (2), in particular a continuous furnace, and a metal melting bath (3), in particular a zinc alloy bath, wherein the furnace nozzle (4) adjoining the furnace (2) immerses its nozzle mouthpiece (6) in the metal melting bath (3).

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