Snout device

Abstract

To provide a snout device that can suppress solidification of metal vapor to both of the expansion pipe and internal cylinder with a simple method.SOLUTION: A snout device includes: first and second cylindrical snouts configured to allow a heat-treated belt-like metal plate to pass therethrough; a plating tank configured to store a molten metal into which a metal plate is immersed; an expansion pipe configured to connect the first snout to the second snout; an internal cylinder installed on an inside of the expansion pipe so as to cover at least part of an inner peripheral surface of the expansion pipe; and a supply part configured to supply an inert gas having a temperature that is higher than a melting point of the molten metal into an internal space between the expansion pipe and the internal cylinder.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a snout device in a continuous molten metal plating line. [Background technology]

[0002] Patent Document 1 discloses a continuous hot-dip plating apparatus including a heat treatment furnace for continuously heat-treating a strip-shaped metal sheet, a plating tank in which the heat-treated metal sheet is immersed in molten metal, and a snout that extends to connect the heat treatment furnace and the plating tank and through which the heat-treated metal sheet can pass toward the plating tank. The lower end of the snout is immersed in the molten metal in the plating tank, and a non-oxidizing atmosphere is maintained from the heat treatment furnace to the snout. A bellows-shaped expansion tube is provided midway through the snout to absorb the expansion and contraction of the snout due to thermal expansion. A heat insulating member and an electric heater are provided on the outer periphery of the expansion tube. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-095598 Summary of the Invention [Problem to be solved by the invention]

[0004] Meanwhile, metal vapor is generated from the surface of the molten metal due to evaporation of the molten metal. If the evaporated metal adheres to the bellows on the inner surface of the expansion tube and solidifies, the solidified metal may fall into the expansion tube, possibly leading to damage to the expansion tube. Also, a metal plate moving inside the snout may unintentionally break and get caught on the expansion tube, possibly leading to damage to the expansion tube. For this reason, an inner tube is sometimes provided inside the expansion tube to protect it.

[0005] However, while an electric heater provided on the outer periphery of the expansion tube as in Patent Document 1 can heat the expansion tube and suppress solidification of metal vapor on the expansion tube, it does not heat the inner tube, which has led to concerns about solidification of metal vapor on the inner tube.

[0006] Therefore, the present disclosure describes a snout device that can suppress solidification of metal vapor on both the expansion tube and the inner tube using a simple method. [Means for solving the problem]

[0007] An example of a snout device includes cylindrical first and second snouts configured to allow a heat-treated strip-shaped metal plate to pass through, a plating tank configured to store molten metal in which the metal plate is immersed, an expandable tube configured to connect the first and second snouts, an inner tube provided inside the expandable tube so as to cover at least a portion of the inner surface of the expandable tube, and a supply unit configured to supply an inert gas at a temperature higher than the melting point of the molten metal to the internal space between the expandable tube and the inner tube. Effect of the Invention

[0008] According to the snout device of the present disclosure, it is possible to suppress solidification of metal vapor on both the expansion tube and the inner tube by a simple method. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic cross-sectional side view of an example of a snout device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] In the following description, the same elements or elements having the same functions are designated by the same reference numerals, and duplicated descriptions will be omitted. In this specification, when referring to the top, bottom, right, and left of the figure, the directions of the reference numerals in the figure are used as the reference.

[0011] [Snout device configuration] The configuration of the snout device 1 will be described with reference to Fig. 1. The snout device 1 is provided, for example, in a continuous hot-dip galvanizing line, and is configured to continuously pass a strip-shaped steel sheet M (metal sheet) through molten metal to apply metal plating to the entire surface of the steel sheet M. As shown in Fig. 1, the snout device 1 includes a continuous annealing furnace 10, a snout section 20, an expandable tube 30, an inner cylinder 40, a heater 50 (heating section), a heat insulating material 60, a plating tank 70, a supply device 80 (supply section), an exhaust device 90 (exhaust section), and a recovery device 100 (recovery section).

[0012] The continuous annealing furnace 10 has a function of annealing (heat treating) the steel sheet M while continuously transporting the steel sheet M by the transport rolls 11. Annealing is a process for removing strain remaining inside the steel sheet M due to the rolling process on the upstream side. In the continuous annealing furnace 10, the steel sheet M is heated, for example, to about 800°C to 900°C. The interior of the continuous annealing furnace 10 is filled with an inert gas. As a result, a non-oxidizing atmosphere is maintained inside the continuous annealing furnace 10. In this specification, the inert gas includes, for example, nitrogen gas, carbon dioxide gas, argon gas, helium gas, etc.

[0013] The snout portion 20 extends obliquely downward as a whole from the continuous annealing furnace 10 toward the plating bath 70. The snout portion 20 includes cylindrical snouts 21 and 22. In the example of Fig. 1, the snouts 21 and 22 each have a rectangular cylindrical shape.

[0014] An upper end of the snout 21 (first snout) is connected to the outlet of the continuous annealing furnace 10. Therefore, the steel sheet M discharged from the outlet of the continuous annealing furnace 10 can pass through the inside of the snout 21. A lower end of the snout 21 is connected to an upper part of the expansion pipe 30.

[0015] The upper end of the snout 22 (second snout) is connected to the lower part of the expansion tube 30. The lower end of the snout 22 is immersed in the molten metal L in the coating tank 70. Therefore, the lower end of the snout 22 is sealed by the molten metal L, and the inside of the snout portion 20 communicating with the continuous annealing furnace 10 is also made into a non-oxidizing atmosphere by the inert gas. In other words, the snout portion 20 is configured to guide the steel sheet M to the molten metal L in the coating tank 70.

[0016] The telescopic tube 30 is configured to connect the snout 21 and the snout 22. The telescopic tube 30 includes a tube body 31, an upper end plate 32, and a lower end plate 33.

[0017] The tube body 31 is bellows-shaped and is configured to be expandable and contractible. Therefore, the tube body 31 can absorb the expansion and contraction of the snouts 21, 22 due to thermal expansion. The tube body 31 is tubular and larger than the outer shapes of the snouts 21, 22, and surrounds the lower end of the snout 21 and the upper end of the snout 22. In the example of FIG. 1, the tube body 31 is tubular, similar to the snouts 21, 22.

[0018] The upper end plate 32 is attached to the opening at the upper end of the tube body 31 so as to cover the opening. The upper end plate 32 has an annular shape with a through hole in the center. The inner peripheral edge of the through hole in the upper end plate 32 is connected to the lower end edge of the snout 21. Therefore, the tube body 31 and the snout 21 communicate with each other while maintaining airtightness.

[0019] The lower end plate 33 is attached to the opening at the lower end of the tube body 31 so as to cover the opening. The lower end plate 33 has an annular shape with a through hole in the center. The inner peripheral edge of the through hole in the lower end plate 33 is connected to the upper edge of the snout 22. Therefore, the tube body 31 and the snout 22 communicate with each other while maintaining an airtight seal.

[0020] The inner cylinder 40 includes an upper inner cylinder 41 and a lower inner cylinder 42. The upper inner cylinder 41 and the lower inner cylinder 42 each have a cylindrical shape. In the example of FIG. 1, the upper inner cylinder 41 and the lower inner cylinder 42 each have a rectangular cylindrical shape, similar to the snouts 21 and 22.

[0021] The upper end of the upper inner tube 41 is attached near the through hole of the upper end plate 32. The lower end of the lower inner tube 42 is attached near the through hole of the lower end plate 33. The lower end of the upper inner tube 41 and the upper end of the lower inner tube 42 are separated from each other in a cross direction that crosses the extending direction of the upper inner tube 41 and the lower inner tube 42. As illustrated in FIG. 1, the upper inner tube 41 may be located outside (on the tube main body 31 side) than the lower inner tube 42. Therefore, the internal space V between the telescopic tube 30 and the inner tube 40 (the space surrounded by the tube main body 31, the upper end plate 32, the lower end plate 33, the upper inner tube 41, and the lower inner tube 42) communicates with the inside of the snouts 21, 22 in the separated area between the upper inner tube 41 and the lower inner tube 42.

[0022] The lower end of the upper inner tube 41 and the upper end of the lower inner tube 42 overlap each other near the center in the extension direction of the tube main body 31 when viewed from the intersecting direction. That is, the upper inner tube 41 covers the region of the inner circumferential surface of the tube main body 31 from the upper end of the tube main body 31 to near the center in the extension direction. The lower inner tube 42 covers the region of the inner circumferential surface of the tube main body 31 from the lower end of the tube main body 31 to near the center in the extension direction. That is, the inner tube 40 covers at least a portion of the inner circumferential surface of the telescopic tube 30.

[0023] The heater 50 is provided on the outer periphery of the tube body 31 and configured to heat the tube body 31. The heater 50 is not fixed to the bellows of the tube body 31 and may be independent of the expansion and contraction of the bellows of the tube body 31. The heater 50 may have a cylindrical shape so as to surround the outer periphery of the tube body 31. In the example of FIG. 1, the heater 50 has a square cylindrical shape like the tube body 31. The heater 50 may be, for example, an electric heater.

[0024] The heat insulating material 60 is provided on the outer periphery of the heater 50 and is configured to suppress the heat for heating the tube body 31 from dissipating to the outside. The heat insulating material 60 is not fixed to the bellows of the tube body 31 and may be independent of the expansion and contraction of the bellows of the tube body 31. The heat insulating material 60 may have a cylindrical shape so as to surround the outer periphery of the tube body 31. In the example of FIG. 1, the heat insulating material 60 has a square cylindrical shape like the tube body 31.

[0025] The plating tank 70 is, for example, a bottomed rectangular cylinder that is open upward and is configured to be able to store molten metal L inside. The molten metal L may be, for example, zinc in a molten state heated to about 400°C to 600°C. The steel sheet M discharged from the lower end of the snout 22 is immersed in the molten metal L, and is transported upward while changing direction by transport rolls 71 arranged in the plating tank 70, and exits the plating tank 70. During this process, the entire surface of the steel sheet M is plated with metal.

[0026] The supply device 80 is configured to supply an inert gas to the internal space V. The supply device 80 includes a gas source 81, a blower 82, and a heating unit 83. The gas source 81 stores an inert gas.

[0027] The blower 82 is configured to send the inert gas from the gas source 81 to the internal space V through the pipe D1.

[0028] The downstream end of the pipe D1 may be connected to at least one of the upper end plate 32 and the lower end plate 33. In the example of Fig. 1, the downstream end of the pipe D1 is connected to two points of the upper end plate 32. In this case, the lower end of the upper inner tube 41 is located outside the upper end of the lower inner tube 42, and the lower end of the upper inner tube 41 overlaps with the upper end of the lower inner tube 42 while being separated from it in the intersecting direction. Therefore, the inert gas supplied from the upper end plate 32 to the internal space V flows through the entire tube body 31, collides with the lower end plate 33, changes its direction by 180°, and flows from the separation area between the upper inner tube 41 and the lower inner tube 42 into the inside of the snouts 21, 22.

[0029] The heating unit 83 is configured to heat the inert gas flowing through the pipe D1 to a temperature higher than the melting point of the molten metal L. The heating unit 83 may be, for example, an electric heater. When the molten metal L is zinc, the heating unit 83 may heat the inert gas to 420°C or higher. When the molten metal L is an alloy of zinc and aluminum, the heating unit 83 may heat the inert gas to about 420°C to 660°C, although this may vary depending on the mixing ratio of these.

[0030] The exhaust device 90 is configured to exhaust gas from within the snouts 21 and 22 to the outside through the pipe D2. The exhaust device 90 may be, for example, an exhaust blower. The exhaust flow rate of the gas by the exhaust device 90 may be set to be equal to or greater than the supply flow rate of the inert gas to the internal space V by the supply device 80. As illustrated in FIG. 1, the upstream end of the pipe D2 may be connected to the downstream side (snout 22) of the telescopic tube 30 and the inner tube 40. Alternatively, although not shown, the upstream end of the pipe D2 may be connected to the upstream side (snout 21) of the telescopic tube 30 and the inner tube 40.

[0031] The recovery device 100 is configured to recover metal vapor contained in the gas exhausted by the exhaust device 90. The recovery device 100 may be, for example, a cooler using a water-cooled pipe or the like. The recovery device 100 may cool the gas passing through the cooler and condense the metal vapor contained in the gas, thereby separating and recovering the metal from the gas.

[0032] [Effect] According to the above example, an inert gas having a temperature higher than the melting point of the molten metal L is supplied to the internal space V between the telescopic tube 30 and the inner tube 40. Therefore, the telescopic tube 30 and the inner tube 40 are heated to a temperature higher than the melting point of the molten metal L. Therefore, even if metal vapor generated by evaporation of the molten metal L reaches the surface of the telescopic tube 30 or the inner tube 40, the metal vapor does not solidify. As a result, it is possible to suppress solidification of metal vapor on both the telescopic tube 30 and the inner tube 40 by the simple method of supplying a high-temperature inert gas.

[0033] According to the above example, the supply device 80 can supply the inert gas to the internal space V from multiple points of the expandable tube 30. In this case, the internal space V is easily filled with the inert gas. This promotes heating of the expandable tube 30 and the inner tube 40 by the inert gas. This makes it possible to further suppress solidification of metal vapor in both the expandable tube 30 and the inner tube 40.

[0034] According to the above example, the supply device 80 can supply the inert gas at 420°C or higher to the internal space V. In this case, when the molten metal L is zinc, the temperature of the inert gas exceeds the melting point of zinc. Therefore, it is possible to suppress the solidification of zinc vapor on both the expandable tube 30 and the inner tube 40.

[0035] According to the above example, the supply device 80 can supply nitrogen as an inert gas to the internal space. In this case, since nitrogen is generally inexpensive, it is possible to suppress solidification of metal vapor on both the expansion pipe 30 and the inner cylinder 40 at low cost.

[0036] According to the above example, the heat insulating material 60 can be provided on the outer periphery of the expansion pipe 30. In this case, the expansion pipe 30 heated by the inert gas is less likely to cool down due to the heat insulating material 60. Therefore, it is possible to further suppress solidification of metal vapor on the expansion pipe 30.

[0037] According to the above example, the heater 50 can be provided on the outer periphery of the expandable tube 30. In this case, the expandable tube 30 is heated by the heater 50 in addition to the inert gas. Therefore, it is possible to further suppress solidification of metal vapor on the expandable tube 30.

[0038] According to the above example, the exhaust device 90 can exhaust gas from inside the snouts 21, 22. In this case, fumes (metal vapor containing fine metal dust) are exhausted to the outside through the exhaust device 90 before solidifying in the telescopic tube 30 and the inner tube 40. Therefore, it is possible to further suppress solidification of metal vapor on both the telescopic tube 30 and the inner tube 40.

[0039] According to the above example, the recovery device 100 can recover metal vapor contained in the gas exhausted by the exhaust device 90. In this case, the exhaust gas from which the metal vapor has been recovered by the recovery device 100 is discharged to the outside of the snout device 1. As a result, the metal vapor is removed from inside the snouts 21, 22, making it difficult for the metal vapor to reach the surfaces of the expandable tube 30 and the inner tube 40. This makes it possible to further suppress solidification of the metal vapor on both the expandable tube 30 and the inner tube 40.

[0040] [Variations] The disclosure in this specification should be considered to be illustrative and not restrictive in all respects. Various omissions, substitutions, modifications, etc. may be made to the above examples without departing from the scope of the claims and the gist thereof.

[0041] (1) Although not shown, the upper inner tube 41 may be located inside (toward the steel plate M) the lower inner tube 42. In this case, the downstream end of the pipe D1 may be connected to the lower end plate 33. Since the lower end of the upper inner tube 41 is located inside the upper end of the lower inner tube 42 and the lower end of the upper inner tube 41 overlaps with the upper end of the lower inner tube 42 while being spaced apart in the intersecting direction, the inert gas supplied from the lower end plate 33 to the internal space V flows through the entire tube body 31, collides with the upper end plate 32, changes its direction by 180°, and flows from the separated region between the upper inner tube 41 and the lower inner tube 42 into the inside of the snouts 21, 22.

[0042] (2) The inner tube 40 may include one of the upper inner tube 41 and the lower inner tube 42. When the inner tube 40 includes the upper inner tube 41 but does not include the lower inner tube 42, the lower end of the upper inner tube 41 may extend to the vicinity of the lower end plate 33 so as not to abut against the lower end plate 33. In this case, the downstream end of the piping D1 may be connected to the upper end plate 32. When the inner tube 40 includes the lower inner tube 42 but does not include the upper inner tube 41, the lower end of the lower inner tube 42 may extend to the vicinity of the upper end plate 32 so as not to abut against the upper end plate 32. In this case, the downstream end of the piping D1 may be connected to the lower end plate 33.

[0043] (3) The snout device 1 does not need to include the heater 50. In this case, the heat insulating material 60 may be provided on the outer periphery of the cylindrical body 31 and configured to suppress the heat of the inert gas for heating the cylindrical body 31 from dissipating to the outside.

[0044] (4) The snout device 1 does not have to include the insulating material 60, or does not have to include both the heater 50 and the insulating material 60.

[0045] (5) The snout device 1 does not necessarily have to include the recovery device 100. The snout device 1 does not necessarily have to include the exhaust device 90.

[0046] [Other examples] Example 1. An example of a snout device includes a cylindrical first snout and a second snout configured to allow a heat-treated strip-shaped metal plate to pass through, a plating tank configured to store molten metal in which the metal plate is immersed, a telescopic tube configured to connect the first snout and the second snout, an inner tube provided inside the telescopic tube so as to cover at least a part of the inner circumferential surface of the telescopic tube, and a supply unit configured to supply an inert gas having a temperature higher than the melting point of the molten metal to an internal space between the telescopic tube and the inner tube. In this case, an inert gas having a temperature higher than the melting point of the molten metal is supplied to the internal space between the telescopic tube and the inner tube. Therefore, the telescopic tube and the inner tube are heated to a temperature higher than the melting point of the molten metal. Therefore, even if the metal vapor generated by the evaporation of the molten metal reaches the surface of the telescopic tube or the inner tube, the metal vapor does not solidify. As a result, it is possible to suppress the solidification of the metal vapor on both the telescopic tube and the inner tube by the simple method of supplying a high-temperature inert gas.

[0047] Example 2 In the device of Example 1, the supply unit may be configured to supply the inert gas to the internal space from multiple points of the expansion tube. In this case, the internal space between the expansion tube and the inner tube is easily filled with the inert gas. This promotes heating of the expansion tube and the inner tube by the inert gas. This makes it possible to further suppress solidification of metal vapor on both the expansion tube and the inner tube.

[0048] Example 3 In the apparatus of Example 1 or Example 2, the supply unit may be configured to supply an inert gas at 420°C or higher to the internal space. In this case, when the molten metal is zinc, the temperature of the inert gas exceeds the melting point of zinc. Therefore, it is possible to suppress solidification of zinc vapor on both the expansion pipe and the inner cylinder.

[0049] Example 4 In any of the devices of Examples 1 to 3, the supply unit may be configured to supply nitrogen as the inert gas to the internal space. In this case, since nitrogen is generally inexpensive, it is possible to suppress solidification of metal vapor on both the expansion pipe and the inner cylinder at low cost.

[0050] Example 5 Any of the devices of Examples 1 to 4 may further include a heat insulating material provided on the outer periphery of the expansion pipe. In this case, the expansion pipe heated by the inert gas is less likely to cool due to the heat insulating material. Therefore, it is possible to further suppress solidification of metal vapor on the expansion pipe.

[0051] Example 6 Any of the devices of Examples 1 to 5 may further include a heating unit provided on the outer periphery of the expansion tube. In this case, the expansion tube is heated by the heating unit in addition to the inert gas. Therefore, it is possible to further suppress solidification of metal vapor on the expansion tube.

[0052] Example 7 Any of the devices of Examples 1 to 6 may further include an exhaust unit configured to exhaust gas from inside the first snout or the second snout. In this case, fumes (metal vapor containing fine metal dust) are exhausted to the outside through the exhaust device 90 before solidifying in the telescopic tube 30 and the inner tube 40. Therefore, it is possible to further suppress solidification of metal vapor on both the telescopic tube and the inner tube.

[0053] Example 8 The device of Example 7 may further include a recovery section configured to recover metal vapor contained in the gas exhausted by the exhaust section. In this case, the exhaust gas from which the metal vapor has been recovered by the recovery section is discharged to the outside of the snout device. As a result, the metal vapor is removed from inside the snout, making it difficult for the metal vapor to reach the surfaces of the telescopic tube and the inner tube. This makes it possible to further suppress solidification of the metal vapor on both the telescopic tube and the inner tube. [Explanation of symbols]

[0054] 1...snout device, 20...snout portion, 21...snout (first snout), 22...snout (second snout), 30...expansion tube, 40...inner tube, 50...heater (heating portion), 60...insulation material, 70...plating tank, 80...supply device (supply portion), 90...exhaust device (exhaust portion), 100...recovery device (recovery portion), L...molten metal, M...steel plate (metal plate), V...internal space.

Claims

1. A cylindrical first snout and a cylindrical second snout configured to allow a heat-treated band-shaped metal plate to pass therethrough; a plating tank configured to store molten metal in which the metal plate is immersed; a telescopic tube configured to connect the first snout and the second snout; an inner tube provided inside the telescopic tube so as to cover at least a portion of an inner circumferential surface of the telescopic tube; a supply unit configured to supply an inert gas having a temperature higher than the melting point of the molten metal to an internal space between the telescopic tube and the inner cylinder.

2. The apparatus of claim 1 , wherein the supply is configured to supply the inert gas to the interior space from a plurality of locations on the telescopic tube.

3. The apparatus of claim 1 or 2, wherein the supply is configured to supply the inert gas at 420° C. or higher to the interior space.

4. 3. The apparatus according to claim 1 or 2, wherein the supply is configured to supply nitrogen as the inert gas to the interior space.

5. The apparatus of claim 1 or 2, further comprising a thermal insulator provided on an outer periphery of the expansion tube.

6. The device according to claim 1 or 2, further comprising a heating section provided on an outer periphery of the expansion tube.

7. The apparatus of claim 1 or 2, further comprising an exhaust configured to exhaust gas from an interior of the first snout or an interior of the second snout.

8. The apparatus of claim 7 , further comprising a recovery section configured to recover metal vapor contained in the gas exhausted by the exhaust section.

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