Shaft cooler for shaft-type electric furnace

Abstract

To provide a shaft cooler of shaft type electric furnace in which water leakage hardly occurs and which can extend the service life of a preheating shaft.SOLUTION: A shaft cooler 32 is provided in a lower part of a preheating shaft that preheats a cold iron source using exhaust gas of a shaft type electric furnace and includes a water-cooling structure, where a first wall part 321 disposed on contra-furnace side being an opposite side of a furnace body of the shaft type electric furnace includes at least one cooling panel selected from a jacket cooler panel, a spray panel, and a non-water-cooling panel. The jacket cooling panel is a cooling panel which is flat on the inner face side and includes a cooling channel where cooling water flows therein. The spray panel is a cooling panel which includes a flat plate-like member disposed on the inner face side and plural nozzles 51 that jet cooling water to the outer face of the plate-like member. The non-water-cooling panel is a cooling panel including no water-cooling structure.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a shaft cooler for a shaft-type electric furnace. [Background technology]

[0002] A shaft-type electric furnace is a highly energy-efficient electric furnace because it preheats a cold iron source, such as scrap, by utilizing the sensible heat of exhaust gas in a preheating shaft when melting the cold iron source. For example, Patent Document 1 discloses an electric furnace (melting furnace) having a preheating shaft as a shaft-type electric furnace. In the shaft-type electric furnace described in Patent Document 1, high-temperature exhaust gas generated during the melting process is discharged through the preheating shaft. At this time, by supplying a cold iron source, such as scrap to be melted, to the melting chamber through the preheating shaft, the cold iron source in the preheating shaft can be preheated by the generated exhaust gas. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-241889 Summary of the Invention [Problem to be solved by the invention]

[0004] In a shaft-type electric furnace such as that described in Patent Document 1, the portion below the preheating shaft is called a shaft cooler. Since high-temperature exhaust gas passes through this shaft cooler, tube coolers are generally provided on the wall surfaces surrounding it on all four sides. Although tube coolers have excellent cooling efficiency, their cross-sectional shape perpendicular to the extension direction is circular, making it difficult to control their wall thickness. As the wall thickness of a tube cooler becomes thinner, it becomes more susceptible to cracks caused by collisions with the cold iron source, raising concerns about water leakage. To enhance cooling capacity, the water pressure flowing through the tube cooler is high, and if a water leak occurs, the amount of water leakage will be large. Furthermore, the increased frequency of repairs shortens the service life of the shaft cooler itself, resulting in long production shutdowns. Furthermore, because the cross-sectional shape of a tube cooler is circular, it is difficult to repair by welding if the wall thickness becomes thin or if a crack occurs.

[0005] Therefore, the present invention has been made in consideration of the above-mentioned problems, and aims to provide a shaft cooler for a shaft-type electric furnace that is less likely to cause water leakage and can extend the service life of the preheating shaft. [Means for solving the problem]

[0006] According to one aspect of the present invention, there is provided a shaft cooler having a water-cooled structure and provided at the bottom of a preheating shaft that preheats a cold iron source using exhaust gas from an electric furnace, wherein a first wall portion provided on the opposite side of the electric furnace body, i.e., the counter-furnace side, has at least one type of cooling panel selected from a jacket cooler panel, a spray panel, and a non-water-cooled panel, the jacket cooler panel having a flat inner surface and a cooling path through which cooling water flows, the spray panel having a flat plate-shaped member provided on the inner surface and a plurality of nozzles that spray cooling water onto the outer surface of the plate-shaped member, and the non-water-cooled panel is a cooling panel that does not have a water-cooled structure. [Effects of the Invention]

[0007] According to one aspect of the present invention, there is provided a shaft cooler for a shaft-type electric furnace that is less susceptible to water leakage and can extend the service life of the preheating shaft. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic cross-sectional view showing a shaft-type electric furnace according to one embodiment of the present invention. [Figure 2] 2A and 2B are schematic diagrams showing a shaft cooler, in which (A) is a plan view and (B) is a cross-sectional view taken along line II in FIG. 2A. [Figure 3] 3A and 3B are schematic diagrams showing a jacket cooler, in which (A) is a front view and (B) is a cross-sectional view taken along line II-II in FIG. 3A. [Figure 4] 4A and 4B are schematic diagrams showing a spray cooler, in which (A) is a front view and (B) is a cross-sectional view taken along line III-III in FIG. 4A. [Figure 5] 5A and 5B are schematic diagrams showing a non-water-cooled panel, in which (A) is a front view and (B) is a cross-sectional view taken along line IV-IV in FIG. 5A. [Figure 6] 6A and 6B are schematic diagrams showing a tube cooler, in which (A) is a front view and (B) is a cross-sectional view taken along line VV in FIG. 6A. DETAILED DESCRIPTION OF THE INVENTION

[0009] In the following detailed description, numerous specific details are set forth to illustrate embodiments of the present invention in order to provide a thorough understanding of the present invention. However, it will be apparent that one or more embodiments may be practiced without such specific details. Also, for the sake of clarity, the drawings may depict well-known structures and devices in simplified form. <Shaft cooler for shaft-type electric furnace> 1 to 6, a shaft cooler 32 of a shaft-type electric furnace 1 according to one embodiment of the present invention will be described. In the drawings, the x-axis, y-axis, and z-axis are mutually perpendicular, the x-axis and y-axis are axes parallel to the horizontal direction, and the z-axis is an axis parallel to the vertical direction. As shown in FIG. 1, the shaft-type electric furnace 1 is an electric furnace that produces molten iron by arc-melting a cold iron source such as scrap, and includes a melting chamber 2 and a preheating shaft 3.

[0010] The melting chamber 2 includes a furnace body 21, an electrode 22, and a pusher 23. The furnace body 21 has an inclined portion 211 on the negative x-axis side, which is the pusher 23 side. In this melting chamber 2, a cold iron source is introduced into the inclined portion 211 through the preheating shaft 3. The introduced cold iron source is pushed toward the positive x-axis side of the furnace body 21 by the pusher 23. The introduced cold iron source is then melted by arc melting using the electrode 22. A tapping port (not shown) for discharging molten iron is provided on the positive y-axis side of the furnace body 21, and a slag discharge port (not shown) for discharging slag is provided on the negative y-axis side of the furnace body 21. For this reason, in the shaft-type electric furnace 1, the positive y-axis side is also referred to as the tapping side, and the negative y-axis side is also referred to as the slag discharge side.

[0011] The preheating shaft 3 is a shaft-type preheating device extending in the vertical direction that uses exhaust gas from the shaft-type electric furnace 1 to preheat the cold iron source to be fed into the shaft-type electric furnace 1. The preheating shaft 3 has a shaft main body 31 provided on the upper side, which is the positive side of the z axis, and a shaft cooler 32 provided on the lower side, which is the negative side of the z axis. The shaft body 31 has a cold iron source inlet 311 and an exhaust port 312 on its upper side, which is the positive side of the z-axis. The cold iron source inlet 311 is an opening through which the cold iron source is introduced from above, and the cold iron source is supplied into the preheating shaft 3 through the cold iron source inlet 311. The exhaust port 312 is connected to an exhaust gas exhaust path (not shown), and exhaust gas generated from the furnace body 21 when the cold iron source is arc-melted is exhausted into this exhaust gas exhaust path.

[0012] The shaft cooler 32 is a rectangular cylindrical member provided below the preheating shaft 3 and is configured separately from the shaft body 31 to protect the shaft body 31 from high-temperature exhaust gas. As shown in FIG. 2 , the shaft cooler 32 has four surrounding walls: a first wall 321, a second wall 322, a third wall 323, and a fourth wall 324. The first wall 321 is a wall provided on the opposite side of the furnace body 21, which is the negative x-axis side (hereinafter also referred to as the "anti-furnace side"). The second wall 322 is a wall provided on the furnace body 21 side, which is the positive x-axis side (hereinafter also referred to as the "furnace side"). In other words, the first wall 321 and the second wall 322 are provided substantially opposite each other in the x-axis direction. In this embodiment, as shown in Fig. 2(B), the second wall portion 322 is formed so that its upward extension direction is inclined toward the negative x-axis direction with respect to the z-axis direction when viewed in a cross section perpendicular to the y-axis direction. The third wall portion 323 is a wall portion provided on the slag discharge side, and the fourth wall portion 324 is a wall portion provided on the steel tapping side. In other words, the third wall portion 323 and the fourth wall portion 324 are provided opposite each other in the y-axis direction, which is perpendicular to the opposing direction of the first wall portion 321 and the second wall portion 322.

[0013] The first wall portion 321 is made up of at least one type of cooling panel selected from a jacket cooler panel 4, a spray panel 5, and a non-water-cooled panel 6. The cooling panel is a member that forms each of the first wall portion 321 to the fourth wall portion 324, and each wall portion is formed by one cooling panel or two or more cooling panels lined up in the in-plane direction on the inner surface. As shown in Fig. 3, the jacket cooler panel 4 is a water-cooled cooling panel having a cooling path through which cooling water flows, and at least the inner surface is made of a metal such as iron (steel). The inner surface of the jacket cooler panel 4 refers to the surface facing the interior of the cylindrical shaft cooler 32, and in Fig. 3, it is the surface on the back side of Fig. 3(A) and the surface on the right side of Fig. 3(B). The cooling water path is preferably formed over almost the entire surface of the jacket cooler panel 4. The cooling water is supplied from a supply port 41 of the jacket cooler panel 4, flows inside the jacket cooler panel 4, and is discharged from a discharge port 42. At least the inner surface of the jacket cooler panel 4 is flat.

[0014] As shown in FIG. 4, the spray panel 5 is a water-cooled cooling panel having a plurality of nozzles 51 for spraying cooling water, and at least the inner surface is made of a metal such as iron (steel). The inner surface of the spray panel 5 refers to the inner surface of the cylindrical shaft cooler 32, which in FIG. 4 is the back surface in FIG. 4(A) and the right surface in FIG. 4(B). The spray panel 5 is made of a metal plate-shaped member 52 with a flat inner surface, and performs cooling by spraying cooling water onto the outer surface of the plate-shaped member 52 from a plurality of nozzles 51 provided on the outside of this plate-shaped member 52. After hitting the plate-shaped member 52, the cooling water sprayed from the plurality of nozzles 51 passes through a cavity inside the spray panel 5 and is discharged from an outlet (not shown) provided at the bottom.

[0015] As shown in Fig. 5, the non-water-cooled panel 6 is a plate-shaped non-water-cooled cooling panel made of metal such as iron (steel). Unlike cooling panels such as the jacket cooler panel 4, spray panel 5, and tube panel, which use cooling water for cooling, the non-water-cooled panel 6 does not use cooling water and is mainly cooled by air. At least the inner surface of the non-water-cooled panel 6 is flat. The inner surface of the non-water-cooled panel 6 is the surface facing the inside of the cylindrical shaft cooler 32, and in Fig. 5, it is the surface on the back side in Fig. 5(A) and the surface on the right side in Fig. 5(B).

[0016] The first wall portion 321 is made of at least one type of cooling panel selected from the jacket cooler panel 4, the spray panel 5, and the non-water-cooled panel 6. In this case, the entire surface of the first wall portion 321 may be made of a single cooling panel, or multiple cooling panels may be arranged in the y-axis or z-axis direction. The first wall portion 321 may also be made of a combination of two or more types of cooling panels. In this case, the first wall portion 321 may be made of two or more types of cooling panels arranged in the in-plane direction of the inner surface, or in the y-axis or z-axis direction.

[0017] Moreover, the first wall portion 321 is preferably made of at least one type of cooling panel selected from the spray panel 5 and the non-water-cooled panel 6, and more preferably made of the non-water-cooled panel 6. In conventional shaft coolers for preheating shafts, a tube cooler panel 7 shown in FIG. 6 has been used as the cooling panel forming each wall. The tube cooler panel 7 is a cooling panel formed by laying metal tubes, such as iron (steel), with a circular cross section. The tube cooler panel 7 performs cooling by allowing cooling water, supplied from a supply port 71 and discharged from a discharge port 72, to flow through the tubes. The tube cooler panel 7 has high cooling capacity because it can pass high-pressure cooling water. However, because the tubes in the tube cooler panel 7 have a circular cross section, the inner surface of the cylindrical shaft cooler 32, which is the back surface in FIG. 6(A) and the right surface in FIG. 6(B), is not flat. This makes it difficult to repair if the wall thickness becomes thin or if cracks occur.

[0018] Among the various cooling panels described above, the cooling capacity increases in the following order: non-water-cooled panel 6, spray panel 5, jacket cooler panel 4, and tube cooler panel 7. Furthermore, the ease of maintenance, such as ease of repair by welding, increases in the following order: tube cooler panel 7, jacket cooler panel 4, spray panel 5, and non-water-cooled panel 6. In particular, the jacket cooler panel 4, spray panel 5, and non-water-cooled panel 6 have flat inner surfaces where thinning and cracking may occur, making repair easier than with the tube cooler panel 7. Furthermore, the jacket cooler panel 4, spray panel 5, and non-water-cooled panel 6 have flat inner surfaces that come into contact with the cold iron source, making it easier to control the wall thickness than with a tube cooler. Therefore, the wall thickness can be appropriately controlled, and thin portions are less likely to occur, resulting in excellent impact resistance.

[0019] Because the first wall portion 321 is located on the opposite side of the furnace body 21, it has a lower thermal load than the other wall portions. Therefore, there is no problem in using cooling panels with low cooling capacity, such as the spray panel 5 or the non-water-cooled panel 6. Furthermore, because such panels are easy to maintain and repair, it is preferable to use at least one type of cooling panel selected from the spray panel 5 and the non-water-cooled panel 6, and it is more preferable to use the non-water-cooled panel 6. When the spray panel 5 is used for the first wall portion 321, the water pressure of the cooling water flowing through the cooling panel is lower than that of the jacket cooler panel 4 or the tube cooler panel 7. Therefore, even if a crack occurs, the amount of cooling water leaking is reduced. Furthermore, if the crack is small, the water leakage is not a problem, so immediate repair is not required. Furthermore, when the non-water-cooled panel 6 is used for the first wall portion 321, water leakage from the first wall portion 321 can be prevented because the cooling panel does not have a water-cooled structure. Furthermore, even if a crack occurs, immediate repair is not required.

[0020] The second wall 322 is made of a jacket cooler panel 4 shown in FIG. 3 . The second wall 322 may consist of a single jacket cooler panel 4 or multiple jacket cooler panels 4. Because the second wall 322 is located on the furnace side (i.e., the furnace body 21), it is subject to a higher thermal load than the other wall sections. Therefore, if a spray panel 5 or a non-water-cooled panel 6 is used, the panel may not be able to withstand the thermal load and may be prone to deformation or cracking. Although the jacket cooler panel 4 has a lower cooling capacity than the tube cooler panel 7, the inventors applied it to the second wall 322 and confirmed that the cooling capacity was sufficient. Therefore, by using the jacket cooler panel 4 for the second wall 322, impact resistance and maintainability can be improved while maintaining cooling capacity.

[0021] The third wall portion 323 and the fourth wall portion 324 may be composed of at least one type of cooling panel selected from the jacket cooler panel 4 shown in FIG. 3, the spray panel 5 shown in FIG. 4, and the non-water-cooled panel 6 shown in FIG. 5. The third wall portion 323 and the fourth wall portion 324 have a higher thermal load than the first wall portion 321 and a lower thermal load than the second wall portion 322. Therefore, to achieve both ease of maintenance and cooling capacity, it is preferable to use the jacket cooler panel 4 or the spray panel 5 as the cooling panel. Furthermore, the third wall portion 323 and the fourth wall portion 324 have a higher thermal load on the furnace side and a lower thermal load on the opposite side. Therefore, it is preferable to use different types of cooling panels on the furnace side and the opposite side. In this case, it is preferable to use the spray panel 5 on the furnace side and the non-water-cooled panel 6 on the opposite side. In this case, for example, the region of approximately 50% of the length of the third wall portion 323 and the fourth wall portion 324 in the x-axis direction on the positive x-axis side may be defined as the furnace side region, and the other region on the negative x-axis side may be defined as the anti-furnace side region.

[0022] In the preheating shaft 3 configured as described above, the cold iron source is introduced through the cold iron source introduction port 311. The introduced cold iron source is stacked on the inclined portion 211 through the preheating shaft 3. The stacked cold iron source is then gradually pushed out from below by the pusher 23, and supplied into the furnace body 21. In addition, in the preheating shaft 3, high-temperature exhaust gas generated in the furnace body 21 passes through the shaft cooler 32 and the inside of the shaft main body 31, and is discharged from the exhaust port 312. At this time, the introduced cold iron source is in the flow path of the exhaust gas, and this cold iron source is preheated.

[0023] <Modification> Although the present invention has been described above with reference to specific embodiments, it is not intended that the invention be limited by these descriptions. By referring to the description of the present invention, other embodiments of the present invention that include various modifications in addition to the disclosed embodiments will be apparent to those skilled in the art. Therefore, it should be understood that the embodiments of the invention set forth in the claims also encompass embodiments that include these modifications described herein, either alone or in combination.

[0024] For example, in the above embodiment, the inner surfaces of the jacket cooler panel 4, the spray panel 5, and the non-water-cooled panel 6 are made of a metal such as iron (steel), but the present invention is not limited to such an example. The material of the inner surfaces of the jacket cooler panel 4, the spray panel 5, and the non-water-cooled panel 6 is not particularly limited as long as it has heat resistance and impact resistance sufficient for practical use of the preheating shaft 3. In addition to heat resistance and impact resistance, from the viewpoint of manufacturing costs, the material is preferably iron (steel).

[0025] Furthermore, the shaft cooler 32 may have a first wall portion 321 made of at least one type of cooling panel selected from the jacket cooler panel 4, the spray panel 5, and the non-water-cooled panel 6, while the second wall portion 322 to the fourth wall portion 324 may be made of the tube cooler panel 7. As described above, all of the wall portions of conventional shaft coolers are made of the tube cooler panel 7. Therefore, by making at least the first wall portion 321, which has the smallest thermal load, made of at least one type of cooling panel selected from the jacket cooler panel 4, the spray panel 5, and the non-water-cooled panel 6, water leakage in the first wall portion 321 is reduced, and the service life of the first wall portion 321 can be extended. In particular, as shown in FIG. 2(B), the lower side of the first wall portion 321 is often inclined relative to the vertical direction when viewed from the y-axis direction. Therefore, the first wall portion 321 is more likely to come into contact with a cold iron source added from above than other wall portions, making it a location prone to cracking. However, by changing the cooling panel of at least the first wall portion 321 as described above, water leaks and cracks are less likely to occur in areas that are likely to come into contact with falling or stacked cold iron sources. This also extends the life of the preheating shaft 3 as a whole. The shaft cooler 32 has a water-cooled structure in at least a portion of at least one of its walls, and preferably, at least a portion of the second wall portion 322 has a water-cooled structure. Having a water-cooled structure means that the cooling panel is a cooling system that uses cooling water, such as the tube cooler panel 7, jacket cooler panel 4, or spray panel 5. Not having a water-cooled structure means that the cooling panel is a cooling system that does not use cooling water, such as the non-water-cooled panel 6.

[0026] <Effects of the embodiment> (1) The shaft cooler 32 of the shaft-type electric furnace 1 according to one embodiment of the present invention is a shaft cooler 32 having a water-cooled structure and provided at the bottom of the preheating shaft 3, which preheats a cold iron source using exhaust gas from the shaft-type electric furnace 1. The first wall portion 321 provided on the opposite side of the shaft-type electric furnace 1 from the furnace body 21 has at least one type of cooling panel selected from a jacket cooler panel 4, a spray panel 5, and a non-water-cooled panel 6. The jacket cooler panel 4 is a cooling panel with a flat inner surface and a cooling path through which cooling water flows. The spray panel 5 is a cooling panel having a flat plate-like member 52 provided on the inner surface and a plurality of nozzles 51 that spray cooling water onto the outer surface of the plate-like member 52. The non-water-cooled panel 6 is a cooling panel that does not have a water-cooled structure. According to the above configuration (1), it is possible to suppress water leakage and damage to the first wall portion 321, and it is possible to extend the life of the preheating shaft 3.

[0027] (2) In the configuration of (1) above, the first wall portion 321 is made of at least one type of cooling panel selected from the spray panel 5 and the non-water-cooled panel 6. According to the above configuration (2), water leakage is less likely to occur than in the above configuration (1). (3) In the configuration of (1) above, the first wall portion 321 is made of a non-water-cooled panel 6. According to the above configuration (2), the first wall portion 321 is made of the non-water-cooled panel 6 that does not have a water-cooling structure, so that water leakage does not occur in the first wall portion 321.

[0028] (4) In any of the above configurations (1) to (3), the second wall portion 322, which is provided on the furnace side, i.e., the furnace body 21 side of the shaft type electric furnace 1, and which faces the first wall portion 321, is made of a jacket cooler panel 4. According to the above configuration (4), by applying the jacket cooler panel 4 to the second wall portion 322, which has the greatest thermal load, it is possible to obtain the necessary cooling capacity while improving impact resistance and making repairs easier compared to when a tube cooler panel 7 is applied.

[0029] (5) In any of the configurations (1) to (4) above, the third wall portion 323 and the fourth wall portion 324, which are provided on the slag discharge side and the steel tapping side of the shaft-type electric furnace 1, respectively, and which face each other, have at least one type of cooling panel selected from the jacket cooler panel 4, the spray panel 5, and the non-water-cooled panel 6. According to the configuration (5) above, the third wall portion 323 and the fourth wall portion 324 can have improved impact resistance while still obtaining the necessary cooling capacity, and furthermore, can be easily repaired.

[0030] (6) In the configuration of (5) above, the third wall portion 323 and the fourth wall portion 324 are made up of spray panels 5 on the furnace side, which is the furnace body side of the shaft-type electric furnace 1, and non-water-cooled panels 6 on the opposite furnace side. According to the above configuration (6), by providing the spray panel 5 on the furnace side where the thermal load is large and the non-water-cooled panel 6 on the opposite side of the furnace where the thermal load is small, it is possible to achieve both cooling capacity and ease of maintenance. [Example]

[0031] As an example, the inventors modified the third wall portion 323, as in the above embodiment, by modifying the furnace side, which is the furnace body side of the shaft-type electric furnace 1, to a spray panel 5 and the opposite furnace side to a non-water-cooled panel 6, and compared the drainage temperature with that of the fourth wall portion 324, which uses a tube cooler panel.

[0032] As a result of the example, when the temperature difference between the supply water temperature and the discharge water temperature during operation was investigated for the third wall portion 323 and the fourth wall portion 324, the average temperature difference for the third wall portion 323 was 7.9°C and the average temperature difference for the fourth wall portion 324 was 8.8°C, confirming that the cooling capacity was at the same level. Furthermore, during a one-year use period, there was zero water leakage and wear on the spray panel 5, confirming that the service life is longer than that of the tube panel. [Explanation of symbols]

[0033] 1 Shaft-type electric furnace 2 Melting chamber 21 Furnace body 211 Slope 22 electrodes 23 Pusher 3 Preheating shaft 31 Shaft body 311 Cold iron source inlet 312 Exhaust port 32 Shaft cooler 321 1st wall section 322 2nd wall section 323 Third wall section 324 4th wall 4 Jacket Cooler Panel 41 Supply port 42 Outlet 5 Spray Panel 51 nozzles 52 Plate-shaped member 6 Non-water-cooled panels 7 Tube Cooler Panel

Claims

1. A shaft cooler for a shaft-type electric furnace, which is provided at a lower part of a preheating shaft that preheats a cold iron source using exhaust gas from the shaft-type electric furnace and has a water-cooling structure, a first wall portion provided on the opposite side of the shaft-type electric furnace body, i.e., the opposite side of the furnace body, having at least one type of cooling panel selected from a jacket cooler panel, a spray panel, and a non-water-cooled panel; The jacket cooler panel is a cooling panel having a flat inner surface and a cooling path through which cooling water flows, The spray panel is a cooling panel having a flat plate-like member provided on an inner surface side and a plurality of nozzles for spraying cooling water onto an outer surface of the plate-like member, the non-water-cooled panel is a cooling panel that does not have a water-cooling structure, The shaft cooler of a shaft-type electric furnace, wherein the first wall portion is made of the non-water-cooled panel.

2. 2. The shaft cooler of claim 1, wherein a second wall portion provided on the furnace side, which is the furnace body side of the shaft electric furnace, and facing the first wall portion is made of the jacket cooler panel.

3. 3. The shaft cooler of claim 1, wherein a third wall portion and a fourth wall portion, which are respectively provided on the slag discharge side and the steel tapping side of the shaft type electric furnace and which face each other, have at least one type of cooling panel selected from the jacket cooler panel, the spray panel, and the non-water-cooled panel.

4. 4. The shaft cooler of claim 3, wherein the third wall portion and the fourth wall portion are made of the spray panel on the furnace side, which is the furnace body side of the shaft type electric furnace, and the non-water-cooled panel on the opposite furnace side.

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