Furnace top cover and induction furnace

Abstract

To provide a furnace top cover of reducing breakage such as cracking caused by expansion in a furnace top cover, and an induction furnace with the furnace top cover installed.SOLUTION: A furnace top cover 1 comprises a cover member 10 and an engagement part 2 in which at least a part is formed at the cover member 10, and which can be engaged with a furnace body 51 of an induction furnace 50. The cover member 10 comprises a tap hole recessed part 3 which can be fitted with a tap hole 52, a bottom face 5 as an installation face to a furnace top part 70, an outer circumferential wall 6 facing an inner circumferential face of the furnace body 51 in a built-in state to the furnace top part 70 and an inner circumferential wall 8 which forms an opening 7 to match the furnace top part 70. The engagement part 2 at least lies between the tap hole recessed part 3 and the bottom face 5. When the engagement part 2 is engaged with the furnace body 51, the relative movement of the furnace top cover 1 in a first direction is regulated with respect to the furnace body 51. When the engagement part 2 is separated from the furnace body 51, the furnace top cover 1 is separable from the furnace body 51 and can open the inside of the induction furnace 50.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a furnace top cover that can be installed in the top portion of an induction furnace, and an induction furnace having a furnace top cover installed therein. [Background technology]

[0002] Conventionally, induction furnaces have had problems associated with high temperatures generated when melting metal placed in a crucible or other shaped refractory material when it is used. When melting metal in a crucible, the crucible becomes hot, and the top of the furnace also becomes hot, which can cause problems such as the crucible or sleeve material inside the furnace expanding and cracking. In particular, it is anticipated that the problem will be that the tapping port will rise up as the sleeve material expands, making it difficult to properly tap the molten metal.

[0003] In order to solve this problem, a furnace top cover for cooling the furnace top of a crucible-type induction furnace has been proposed. For example, according to Patent Document 1, as shown in FIG. 20, a furnace top cover 820 is composed of a cylindrical body 822 made of steel attached to the side of a ring-shaped body 821 made of a thin steel material having a cavity 820a. The cavity 820a is used as a water passage port for cooling water, and has an inlet part 823 and an outlet part 824 for cooling water, and is partitioned at a predetermined interval by a partition plate 825 having a reinforcing function. In this case, the partition plate 825 has two water passage ports 826 at a predetermined height from the bottom. The ring-shaped body 821 extends so as to cover the tapping port, and the cavity of this extension part communicates with the cavity of the ring-shaped body 821 through a water passage port 827.

[0004] According to this configuration, the cavity 820a spreads throughout the inside of the ring-shaped body 821, and the cooling water spreads throughout the cavity 820a. In a crucible-type induction furnace, the part to be cooled is the part close to the inner circumference which is likely to become hot, and in this case, the refractory bricks are also included in the cooling target. For the sake of explanation, the reference numerals in Fig. 20 are different from those in the drawing in Patent Document 1, but the components and their functions are similar. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Practical application 156003-156003 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the conventional example, the cavity 820a extends from the inner circumference to the outer circumference, far from the inner circumference of the crucible-type induction furnace, and the cooling water extends to the outer circumference. Therefore, the cooling water spreads to areas other than the area that is originally intended to be cooled, and it is expected that the cooling effect will decrease. In addition, in the configuration of the conventional example, the cooling water does not reach the periphery of the tapping hole, so the cooling effect around the tapping hole cannot be expected. Therefore, the problem of the tapping hole floating up is not solved at all.

[0007] The object of the present invention is to solve the problems of the related art and to provide a furnace top cover that reduces damage such as cracks caused by expansion of the furnace top, including the tapping hole, and an induction furnace incorporating such a furnace top cover. [Means for solving the problem]

[0008] A furnace top cover according to a first aspect of the present invention is capable of being installed in the top portion of a cylindrical induction furnace, and comprises a cover member and an engaging portion formed at least in part in the cover member and capable of engaging with an engaged portion of the furnace body of the induction furnace, the cover member comprises a tapping hole recess to which a tapping hole can be attached, a bottom surface which is an installation surface for the furnace top portion, an outer peripheral wall which faces an inner peripheral surface of the furnace body when installed in the furnace top portion, and an inner peripheral wall which forms an opening, and the cover member is made of a shaped refractory material. a cylindrical central axis of the induction furnace and an opening central axis of the opening are approximately collinear, a direction along the cylindrical central axis is a first direction, and a direction perpendicular to the first direction is a second direction, the engaging portion is located at least between the tapping port recess and the bottom surface, and when the engaging portion engages with the furnace body, relative movement in the first direction with respect to the furnace body is restricted, and when the engaging portion moves away from the furnace body, it can be separated from the furnace body, and the inside of the induction furnace can be opened.

[0009] According to this, the engagement portion of the furnace cover is at least between the tap hole recess and the bottom surface, and when the engagement portion engages with the furnace body, the relative movement in the first direction with respect to the furnace body is restricted. Therefore, even if the temperature around the furnace top becomes high and the furnace top expands, the furnace cover can suppress cracks and lifting of the furnace top. Since the engagement portion is formed at least between the tap hole recess and the bottom surface, the tap hole is suppressed from lifting.

[0010] When the engaging portion is separated from the furnace body, the furnace top cover can be separated from the furnace body, and the inside of the induction furnace can be opened. Therefore, when repairing the inside of the induction furnace or replacing internal parts, etc., the internal parts inside the furnace can be easily removed by removing the furnace top cover.

[0011] Furthermore, since the cover member is made of shaped refractory material, it is possible to suppress the application of induction heating, thereby reducing energy loss and allowing the metal in the furnace to be melted efficiently.

[0012] Furthermore, the furnace top cover may include a split cover member divided into several parts in a circumferential direction centered on the opening central axis, and the engaging portion may be a convex portion protruding in the second direction from the outer peripheral wall of each of the split cover members, and each of the split cover members may be moved in different directions in a radial direction centered on the cylindrical central axis, so that the convex portion can engage with the engaged portion formed on the inner peripheral surface of the furnace body.

[0013] In this case, the split cover member can be moved in different radial directions around the central axis of the cylinder so that the protrusions can engage with the engagement parts formed on the inner circumferential surface of the furnace body. Therefore, since the protrusions can engage with the engagement parts over the circumferential direction, the split cover member can further suppress cracks and lifting of the furnace top.

[0014] In addition, the furnace top cover is provided with an auxiliary cover member that is attached to the gap that occurs between the split cover members adjacent to the circumferential direction when the split cover members are assembled into the furnace top portion, and covers a portion of the furnace top portion, and the auxiliary cover member may be formed from a shaped refractory material and may be in at least partial contact with the circumferentially adjacent split cover members or have a gap of less than a predetermined amount.

[0015] In this case, since the furnace top portion is covered in the circumferential direction by the split cover member and the auxiliary cover member, the furnace top cover can better suppress cracks and lifting up of the furnace top portion.

[0016] In addition, the auxiliary cover member of the furnace top cover may have side surfaces in the circumferential direction that are parallel to each other along the radial direction when assembled to the furnace top part. In this case, the auxiliary cover member can be assembled to the furnace top part by moving it in the radial direction when the split cover member is assembled to the furnace top part.

[0017] Furthermore, when the auxiliary cover member and the split cover member are assembled into the furnace top portion, the split cover side surface of the split cover member that is adjacent to and faces the auxiliary cover member in the circumferential direction is parallel to the auxiliary cover side surface, and the auxiliary cover side surface and the split cover side surface may be in contact with each other including surface contact or have a gap of a predetermined amount or less.

[0018] In this case, the auxiliary cover member and the split cover member that are adjacent and facing each other in the circumferential direction can contact each other or have a gap of a predetermined amount or less because the auxiliary cover side and the split cover side are parallel. Therefore, since the split cover member and the auxiliary cover member continuously cover the furnace top part in the circumferential direction, the furnace top cover can suppress cracks and lifting in the entire circumferential direction.

[0019] Furthermore, the furnace top cover may include an auxiliary cover outer wall that faces the inner surface of the furnace body when the auxiliary cover member is incorporated into the furnace top portion, and an auxiliary convex portion that protrudes in the second direction from the auxiliary cover outer wall, and the auxiliary cover member may be capable of engaging with the engageable portion formed on the inner surface of the furnace body by moving the auxiliary cover member in the radial direction when the split cover member is incorporated into the furnace top portion.

[0020] In this case, when the split cover member is assembled into the furnace top portion, the auxiliary convex portion can engage with the engaged portion of the furnace body, so that the split cover member and the auxiliary cover member can better suppress cracks and lifting up of the furnace top portion.

[0021] In addition, the furnace top cover may be configured so that the auxiliary cover member has an auxiliary side convex portion protruding in the second direction on the auxiliary cover side surface, and the split cover member has a split cover recess on the split cover side surface, and the auxiliary cover member is capable of engaging with the split cover recess by moving it in the radial direction when the split cover member is assembled into the furnace top portion.

[0022] In this case, when the auxiliary cover member is assembled into the furnace top portion, it can be moved radially so that the auxiliary side convex portion can engage with the split cover concave portion. Therefore, by integrating the auxiliary cover and the split cover, cracks and lifting up of the furnace top portion can be further suppressed.

[0023] Furthermore, the furnace top cover may have an engaging portion that includes an engaging recess and an engaging member, the engaging recess being a recess formed from the outer peripheral wall of the cover member to halfway along the inner peripheral wall in the second direction, and the engaging member being capable of engaging with the engaged portion that is formed penetrating from the outer peripheral surface of the furnace body to the inner peripheral surface in the second direction, and the engaging recess.

[0024] In this case, the engaging member can be inserted from the outer circumferential surface of the furnace body to engage with the engaged portion and the engaging recess of the furnace body. Therefore, the furnace top cover can be assembled to the furnace top with a simple construction work, and cracks and lifting of the furnace top can be suppressed.

[0025] The induction furnace of the second aspect of the present invention comprises the furnace top cover, the furnace body, a sleeve material installed inside the furnace body, an amorphous refractory material filling the space between the inside of the furnace body and the sleeve material, and the tapping outlet, at least a portion of the furnace top cover is incorporated between the sleeve material and the tapping outlet, and when the engaging portion is engaged with the engaged portion, the relative movement of the top cover in the first direction with respect to the furnace body is restricted, and when the engaging portion is released from the engaged state with the engaged portion, the top cover can be separated from the furnace body together with the tapping outlet, and the sleeve material can be removed from inside the furnace body.

[0026] In this case, when the engaging portion engages with the engaged portion formed on the furnace body, the relative movement of the furnace top cover in the first direction with respect to the furnace body is restricted. Therefore, the induction furnace can suppress cracks and lifting of the furnace top cover.

[0027] Furthermore, when the engaging portion is released from the engaged state with the engaged portion, the furnace top cover can be separated from the furnace body together with the tap hole, and the sleeve material can be removed from inside the furnace body. Therefore, the induction furnace can easily perform repair work inside the furnace body or replace internal parts. [Brief description of the drawings]

[0028] [Figure 1] FIG. 1 is a cross-sectional view showing a perspective view of an induction furnace 50a of the present invention in which a furnace top cover 1a of a first embodiment of the present invention is assembled. [Diagram 2] 1 and is a cross-sectional view taken along a cylindrical central axis C1. [Diagram 3] FIG. 3 is a view seen from the direction A in FIG. [Figure 4] FIG. 2 shows the furnace body 51 with the tapping hole 52 and the furnace top cover 1a removed. [Diagram 5] 5 is a diagram showing a state in which a sleeve material 55 inside the furnace body 51 is being attached and detached from the state shown in FIG. 4. FIG. [Figure 6] 1A and 1B are diagrams showing a first divided cover member 20a, a second divided cover member 20b, and an auxiliary cover member 23a in a furnace cover 1a according to a first embodiment of the present invention, where (a) is a perspective view and (b) is a plan view. [Figure 7] This is a figure corresponding to view A in Figure 2, showing the procedure for assembling the first split cover member 20a and the second split cover member 20b into the furnace top portion 70 in the furnace top cover 1a of the first embodiment of the present invention, where (a) shows the furnace top portion 70 before the first split cover member 20a and the second split cover member 20b are assembling, (b) shows the state in which the first split cover member 20a and the second split cover member 20b are placed on the furnace top portion 70, and (c) shows the state in which the first split cover member 20a and the second split cover member 20b have been moved radially and the auxiliary cover member 23 has been further assembling. [Figure 8]8A and 8B are cross-sectional views corresponding to FIG. 7, where (a) is a cross-sectional view showing section II in FIG. 7, (b) is a cross-sectional view showing section II-II in FIG. 7, showing the state before the tapping port 52 is installed, and (c) shows the state after the tapping port 52 is installed in comparison to (b). [Figure 9] This is a diagram showing a furnace top cover 1b of the second embodiment of the present invention, showing a first divided cover member 20a, a second divided cover member 20b, and an auxiliary cover member 23b, where (a) is an oblique view and (b) is a plan view. [Figure 10] This is a figure showing a furnace top cover 1b of the second embodiment of the present invention, showing the procedure for further incorporating the auxiliary cover member 23b from the state shown in Figure 7(b), where (a) shows the state in which the auxiliary cover member 23b is inserted between the first split cover member 20a and the second split cover member 20b and moved in the directions of the arrows U1 and U2, and (b) shows the state in which the auxiliary cover member 23b has been incorporated. [Figure 11] 10(a) is a cross-sectional view showing the section III-III in FIG. 10(a), and FIG. 10(b) is a cross-sectional view showing the section IV-IV in FIG. 10(b). [Figure 12] This figure shows the furnace top cover 1c of the third embodiment of the present invention, and corresponds to view A in Figure 2, showing the procedure for assembling the third split cover member 20c, the fourth split cover member 20d and the auxiliary cover member 23c into the furnace top section 70, where (a) shows the third split cover member 20c and the fourth split cover member 20d, (b) shows the state in which the third split cover member 20c and the fourth split cover member 20d are placed on the furnace top section 70 and moved in the radial directions of arrows H1 and H2, and (c) shows the state in which the third split cover member 20c is rotated in the direction of arrow R1, the fourth split cover member 20d is rotated in the direction of arrow R2, and then the auxiliary cover member 23c is moved in the radial direction of arrow U1 to be assembled. [Figure 13] 13 is a plan view showing the fifth divided cover member 20e, the sixth divided cover member 20f, and the seventh divided cover member 20g of a top cover 1d according to a fourth embodiment of the present invention. FIG. [Figure 14]This is a figure corresponding to view A in Figure 2, showing the procedure for assembling the fifth split cover member 20e, the sixth split cover member 20f, and the seventh split cover member 20g, as well as the auxiliary cover member 23d, into the furnace top section 70 in the furnace cover 1d of the fourth embodiment of the present invention, where (a) shows the state in which the fifth split cover member 20e is moved radially in the direction of arrow D1 to be assembled, (b) shows the state in which the sixth split cover member 20f is then moved radially in the direction of arrow D2 to be assembled, and (c) shows the state in which the sixth split cover member 20f is rotated in the direction of arrow R1, the seventh split cover member 20g is moved radially in the direction of arrow D3 and then rotated in the direction of arrow R2, and the auxiliary cover member 23d is moved radially in the direction of arrow H2 to be assembled. [Figure 15] 13A and 13B are diagrams showing a furnace top cover 1e of the fifth embodiment of the present invention, illustrating an eighth split cover member 20h, a ninth split cover member 20j, and an auxiliary cover member 23e, in which (a) is an oblique view and (b) is a plan view. [Figure 16] 10A and 10B are views showing a furnace top cover 1e according to a fifth embodiment of the present invention, and show a furnace top cover 1b according to the second embodiment. [Figure 17] 16(a) is a cross-sectional view showing the cross section VV in FIG. 16(a), and FIG. 16(b) is a cross-sectional view showing the cross section VI-VI in FIG. 16(b). [Figure 18] FIG. 13 is a cross-sectional view showing a furnace top cover 1f according to a sixth embodiment of the present invention and an induction furnace 50e in which the furnace top cover 1f is incorporated, which corresponds to FIG. 2 of the first embodiment. [Figure 19] 13A and 13B are diagrams showing a cover member 10f in a furnace top cover 1f according to a sixth embodiment of the present invention, in which (a) is a perspective view and (b) is a plan view. [Figure 20] FIG. 1 is a plan view showing a conventional furnace top cover 820. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] Hereinafter, a furnace top cover 1 and an induction furnace 50 embodying the present invention will be described with reference to the drawings. The description of the embodiment of the invention and the drawings to which reference is made are used to explain technical features that may be adopted by the present invention. The present invention is not limited thereto. The configurations shown in the drawings are merely illustrative examples and are not intended to limit the scope of the present invention.

[0030] <Configuration of induction furnace 50> First, with reference to Figs. 1 to 4, an outline of the configuration of the induction furnace 50 in which the furnace top cover 1 is incorporated will be described. The induction furnace 50 will be described taking a crucible-type induction furnace as an example. As shown in Figs. 1 and 2, the induction furnace 50 is formed in a cylindrical shape, and the center of the cylinder is the central axis C1 of the cylinder. The direction along the central axis C1 of the cylinder is the first direction, and the direction perpendicular to the first direction is the second direction. Assuming that the first direction is a direction along the vertical direction, the first direction is the up-down direction, and the upper side and the lower side are defined. The furnace top cover 1 is installed on the upper side of the furnace top part 70. The furnace top cover 1 is formed in a doughnut shape in a planar direction expanding in the second direction. In the second direction, the side facing the central axis C1 of the cylinder is the inside, and the opposite side is the outside.

[0031] As shown in Figures 1 and 2, inside the induction furnace 50, a sleeve material 55 is attached around the cylindrical central axis C1, and an inner bottom material 61 is formed at the bottom, forming a container (crucible) for pouring, melting, and holding materials. The material is, for example, a light metal material such as aluminum, or a metal material such as cast iron. The sleeve material 55 is covered with a back material 56, and a coil 57 is formed on the outside, fixed with coil cement 58. The coil 57 is covered with a yoke 59, and an outer shell is formed with a steel plate 60.

[0032] The sleeve material 55 is a shaped material, and the back material 56 is an unshaped material. The material of the sleeve material 55 is a refractory material such as alumina, silica, magnesia, etc. The back material 56 is powdered alumina, silica, magnesia, etc., and is inserted between the sleeve material 55 and the coil cement 58 and hardened. The inner bottom material 61 is an unshaped material with the same components as the sleeve material 55, and is also made of the same material. Above the coil cement 58, the coil presser 54 is formed from a shaped material.

[0033] The induction furnace 50 is formed with a tapping hole 52 for pouring the molten metal in the crucible on the upper side. As will be described later, the furnace top cover 1 is provided with a tapping hole recess 3 to which the tapping hole 52 can be attached.

[0034] A base material 62, which is an amorphous material similar to the back material 56, is formed on the lower side of the inner bottom material 61, and further below that, a bottom plate brick 63 is formed. Toward the upper side of the steel plate 60, an iron plate stage 64 is formed in a direction expanding in the planar direction.

[0035] 4 shows the furnace body 51 with the top cover 1 removed. The furnace body 51 and its internal parts, etc. of the induction furnace 50 are defined as follows. The furnace body 51 is composed of an outer shell formed of steel plates 60, an iron plate stage 64, a coil 57 fixed by coil cement 58, a yoke 59 covering the coil 57, a bottom plate brick 63, and a coil retainer 54. The internal parts of the furnace body 51 are the top cover 1, a sleeve material 55, a back material 56, an inner bottom material 61, and a base material 62.

[0036] In the induction furnace 50, the metal material to be melted is put into a crucible formed by a sleeve material 55 and an inner bottom material 61. When an alternating current is applied to the coil 57, a magnetic field is generated in the crucible, and an electric current flows through the metal material put in due to electromagnetic induction, and the metal material itself generates heat and melts due to its electrical resistance. The temperature when the metal melts is about 1500 degrees Celsius. This heat causes the inside of the crucible to become hot, and the temperature rise is particularly rapid near the crucible, with the sleeve material 55 rising the most. Therefore, the upper part of the sleeve material 55 in the furnace top 70 is prone to expansion, cracks, etc. If the sleeve material 55 expands and directly affects the tapping port 52, the tapping port 52 will rise up and cause problems when tapping.

[0037] If the cover member 10 forming the furnace top cover 1 were made of a metal material, induction heating would occur, causing the temperature to rise and leading to a loss of energy for melting the metal in the crucible. The furnace top cover 1 of the present invention solves the above problems.

[0038] <Configuration common to all embodiments of the furnace top cover 1> Next, a configuration common to each embodiment of the furnace top cover 1 according to the first aspect of the present invention will be described. The description will be made with reference to Figs. 1 to 6 showing the furnace top cover 1a of the first embodiment. The furnace top cover 1 can be incorporated into the furnace top section 70 of a cylindrical induction furnace 50. The furnace top cover 1 comprises a cover member 10 and an engagement section 2 at least a part of which is formed in the cover member 10 and can engage with the furnace body 51 of the induction furnace 50.

[0039] As shown in the examples of Figures 2 and 6, the cover member 10 includes a recess 3 for a tapping port to which a tapping port 52 can be attached, a bottom surface 5 which is a surface to be installed on the furnace top 70, an outer peripheral wall 6 which faces the inner peripheral surface of the furnace body 51 when assembled to the furnace top 70, and an inner peripheral wall 8 which forms an opening 7. As shown in Figures 2 and 4, the inner peripheral surface of the coil holder 54 corresponds to the inner peripheral surface of the furnace body 51 in the furnace top 70, and forms the furnace top opening 71. The cover member 10 is formed of a shaped refractory. Examples of the shaped refractory include silica bricks, clay bricks, zirconia bricks, high alumina bricks, magnesia bricks, magnesia chrome bricks, magnesia carbon bricks, and alumina carbon bricks, and other materials may be used. The shaped refractory includes ceramics.

[0040] As shown in Figures 1 and 2, the cylinder central axis C1 of the induction furnace 50 and the opening central axis C2 of the opening 7 are substantially on the same line. The direction along the cylinder central axis C1 is defined as a first direction, and the direction perpendicular to the first direction is defined as a second direction. The engagement portion 2 is located at least between the tap hole recess 3 and the bottom surface 5. When the engagement portion 2 engages with the furnace body 51, the relative movement of the furnace top cover 1 with respect to the furnace body 51 in the first direction is restricted. When the engagement portion 2 moves away from the furnace body 51, the furnace top cover 1 can be separated from the furnace body 51, and the inside of the induction furnace 50 can be opened.

[0041] As shown in FIG. 2, the bottom surface 5 of the cover member 10 of the furnace top cover 1 contacts the sleeve material 55 and the back material 56 via mortar 53, patching material, wet powder material, etc., or directly without mortar 53, etc. The outer peripheral wall 6 and the inner peripheral surface of the coil holder 54 forming the furnace top opening 71 are simply opposed to each other, and no adhesive such as mortar 53 is used. Similarly, no adhesive such as mortar 53 is used between the engaging portion 2 and the engaged portion 65 formed on the furnace body 51, or the engaged portion 66 shown in FIG. 18 described later. Therefore, when the engaging portion 2 is separated from the furnace body 51, the furnace top cover 1 can be removed from the furnace body 51 by simply peeling off the mortar between the sleeve material 55 and the back material 56.

[0042] <Repairs and part replacements inside furnace body 51> With reference to Figs. 4 and 5, the case of repairing the inside of the furnace body 51 or replacing the internal parts will be described. The induction furnace 50 is in a harsh environment where the inside of the furnace body 51 is exposed to high temperatures, and therefore the internal structures or parts may be damaged and repairs or the like may be required. Taking Fig. 2 as an example, the sleeve material 55, the inner bottom material 61, and the furnace top cover 1 are directly exposed to the high-temperature molten metal. In addition to the parts directly exposed to the molten metal, the parts that may need to be replaced or repaired may include the adjacent back material 56, the base material 62, and even the coil cement 58. The furnace top cover 1 of the present invention can be removed from the furnace body 51, so that the inside of the furnace body 51 can be repaired, parts can be replaced, and the like.

[0043] As shown in Figure 5, when the sleeve material 55 is removed from the state shown in Figure 4, the back material 56, inner bottom material 61, and base material 62, which are amorphous refractories, turn into powder and remain inside the furnace body 51, but can be scraped out to the outside. Then, the inside of the furnace body 51 becomes exposed, making it possible to repair the coil cement 58, etc. If the sleeve material 55 is damaged, it is replaced and applied to the furnace body 51.

[0044] <Effects of the configuration common to all embodiments of the furnace top cover 1> The above-described common configuration of the top cover 1 provides the following effects. As shown in Fig. 1 to Fig. 6 as an example, the top cover 1 has an engagement portion 2 located at least between the tap hole recess 3 and the bottom surface 5, and when the engagement portion 2 engages with the furnace body 51, the relative movement in the first direction with respect to the furnace body 51 is restricted. Therefore, the top cover 1 can suppress cracks and lifting of the furnace top portion 70 even if the furnace top portion 70 and its surroundings become hot and expand. Since the engagement portion 2 is formed at least between the tap hole recess 3 and the bottom surface 5, the tap hole 52 is suppressed from lifting.

[0045] In addition, since the cover member 10 is made of shaped refractory material, it is possible to suppress the application of induction heating, thereby reducing energy loss and allowing the metal in the furnace to be melted efficiently.

[0046] 4 and 5, when the engaging portion 2 is separated from the furnace body 51, the furnace top cover 1 can be separated from the furnace body 51, and the inside of the induction furnace 50 can be opened. Therefore, when repairing or replacing the inside of the induction furnace 50, the structure inside the furnace can be easily removed by removing the furnace top cover 1.

[0047] Induction furnaces 50 may be manufactured in a factory including the internal parts of the furnace body 51 and distributed, or may be shipped from the factory with only the furnace body 51, and the internal parts of the furnace body 51 may be installed at the site where the furnace is to be used. The furnace top cover 1 of the present invention is particularly effective in the latter case, since it can be assembled to the furnace body 51.

[0048] Furthermore, when repairs are required inside the furnace body 51, the entire induction furnace 50 does not need to be transported to the factory, and the work can be done at the site where it is used. When internal parts of the furnace body 51 need to be replaced, only the replacement parts can be transported from the factory, and the work can be carried out at the site where it is used, and the furnace top cover 1 can be installed.

[0049] <<Configuration and effects common to multiple embodiments of the furnace top cover 1>> Next, the configuration and effects common to a plurality of embodiments of the furnace top cover 1 according to the first aspect of the present invention will be described. Note that the description of the common configuration and effects already described will be omitted.

[0050] <Configuration common to the furnace top cover 1a of the first embodiment to the furnace top cover 1e of the fifth embodiment> A configuration common to the top cover 1a of the first embodiment according to the first aspect of the present invention to the top cover 1e of the fifth embodiment will be described. As shown in FIG. 6 and other figures, the cover member 10 of the top cover 1 is provided with a plurality of divided cover members 20 in the circumferential direction centered on the opening central axis C2. The engagement portion 2 is a convex portion 11 protruding in the second direction from the outer peripheral wall 6 of each divided cover member 20. As shown in FIG. 7, FIG. 10, FIG. 12, FIG. 14, and FIG. 16, each divided cover member 20 can be moved in different directions in the radial direction centered on the cylindrical central axis C1, so that the convex portion 11 can engage with a groove portion, which is an engaged portion 65 formed on the inner peripheral surface of the furnace body 51. As shown by the dashed lines in FIG. 4, FIG. 7, and FIG.

[0051] 6, 7, 9, 10, 12, 14, and 16, the furnace top cover 1 includes an auxiliary cover member 23 that is attached to a gap generated between adjacent split cover members 20 in the circumferential direction when the split cover members 20 are assembled into the furnace top portion 70, and covers a part of the furnace top portion 70. The auxiliary cover member 23 is formed of a shaped refractory material, and at least a part of the auxiliary cover member 23 is in contact with the split cover members 20 adjacent in the circumferential direction, or has a gap of a predetermined amount or less.

[0052] Furthermore, as shown in Figures 6, 7, 9, 10, 12, 14, and 16, when the auxiliary cover member 23 of the furnace top cover 1 is assembled into the furnace top portion 70, the circumferential side surfaces are auxiliary cover side surfaces 24 that are parallel to each other along the radial direction.

[0053] 6, 7, 9, 10, 12, 14, and 16, when the auxiliary cover member 23 and the split cover member 20 are assembled into the furnace top portion 70, the split cover side surface 14 of the split cover member 20 adjacent to and facing the auxiliary cover member 23 in the circumferential direction is parallel to the auxiliary cover side surface 24. The auxiliary cover side surface 24 and the split cover side surface 14 are in contact with each other, including surface contact, or have a gap of a predetermined amount or less.

[0054] <Effects of the configuration common to the furnace top cover 1a of the first embodiment to the furnace top cover 1e of the fifth embodiment> The above-described configuration provides the following effects. As shown in Figures 7, 10, 12, 14, and 16, the split cover member 20 can be moved in different directions in the radial direction around the cylindrical central axis C1, so that the convex portion 11 can engage with the groove portion, which is the engaged portion 65 formed on the inner circumferential surface of the furnace body 51. Therefore, the furnace top cover 1 can further suppress cracks and lifting of the furnace top portion 70, since the convex portion 11 can engage with the groove portion, which is the engaged portion 65, over the circumferential direction.

[0055] Moreover, each of the split cover members 20 is more compact and lightweight than when they are formed as one piece, making them easier to transport and handle. The protrusions 11, which are the engaging portions 2, are formed as one piece on the outer peripheral wall 6 of the split cover members 20, eliminating the need to prepare engaging parts, making it possible to reduce costs. Furthermore, the furnace top cover 1 is formed only from shaped refractories, making it less likely to be dielectrically heated.

[0056] Furthermore, as shown in FIG. 6 etc., the furnace top portion 70 is covered in the circumferential direction by the split cover member 20 and the auxiliary cover member 23, so that the furnace top cover 1 can further suppress cracks and lifting of the furnace top portion 70.

[0057] In addition, the split cover member 20 and the auxiliary cover member 23 can be easily removed from the furnace body 51. In the example shown in Fig. 7 etc., the split cover member 20 can be removed by first removing the auxiliary cover member 23, and then moving it in the opposite direction to that in which it was assembled. Details will be described in each individual embodiment.

[0058] 6 and other figures, the auxiliary cover member 23 of the furnace top cover 1 has circumferential side surfaces 24 that are parallel to each other along the radial direction, so that with the split cover member 20 assembled to the furnace top portion 70, it can be moved radially to be assembled to the furnace top portion 70. As will be described later, if the auxiliary cover member 23 has an auxiliary protrusion 27, the auxiliary protrusion 27 can be engaged with the groove portion, which is the engaged portion 65, by moving it radially.

[0059] 6, the auxiliary cover member 23 and the split cover member 20, which are adjacent and opposed in the circumferential direction, can be in contact with each other, including surface contact, or have a gap of a predetermined amount or less, because the auxiliary cover side surface 24 and the split cover side surface 14 are parallel. Therefore, in the furnace top cover 1, the split cover member 20 and the auxiliary cover member 23 continuously cover the furnace top portion 70 in the circumferential direction, so that cracks and lifting in the furnace top portion 70 can be suppressed in the entire circumferential direction.

[0060] <Configurations and effects common to the furnace top cover 1b of the second embodiment to the furnace top cover 1e of the fifth embodiment> Next, the configuration common to the second embodiment of the furnace top cover 1b to the fifth embodiment of the furnace top cover 1e according to the first aspect of the present invention will be described. As shown in Fig. 9, the auxiliary cover member 23 of the furnace top cover 1 has an auxiliary cover outer peripheral wall 26 that faces the inner peripheral surface of the furnace body 51 when assembled into the furnace top part 70, an auxiliary convex part 27 that protrudes from the auxiliary cover outer peripheral wall 26 in the second direction, and auxiliary cover side surfaces 24 that are parallel to each other in the circumferential direction.

[0061] As shown in Figure 10, the auxiliary cover member 23 can be moved radially with the split cover member 20 assembled into the furnace top portion 70, so that the auxiliary protrusion 27 can engage with a groove portion, which is an engagement portion 65 formed on the inner surface of the furnace body 51.

[0062] The above-described configuration provides the following effects. When the split cover members 20 are assembled into the furnace top section 70, the auxiliary convex portion 27 of the auxiliary cover member 23 of the furnace top cover 1 can engage with the groove portion, which is the engaged portion 65 of the furnace body 51. Therefore, the split cover members 20 and the auxiliary cover member 23 of the furnace top cover 1 can further suppress cracks and lifting of the furnace top section 70.

[0063] <<Configurations and Effects Unique to Each Embodiment>> Next, the configurations and effects unique to each of the furnace top cover 1a of the first embodiment to the furnace top cover 1f of the sixth embodiment according to the first aspect of the present invention will be described. Note that the description of the common configurations and effects already described will be omitted.

[0064] <Configuration of the furnace top cover 1a of the first embodiment> With reference to Fig. 6 to Fig. 8, the furnace top cover 1a of the first embodiment according to the first aspect of the present invention will be described. The furnace top cover 1a includes two divided cover members 20, a first divided cover member 20a, a second divided cover member 20b, and two auxiliary cover members 23a. As shown in Fig. 6, the first divided cover member 20a and the second divided cover member 20b have a half-moon shape with a concave inner side in a plan view. As shown in Fig. 7(c), the two auxiliary cover members 23a have a symmetrical shape with respect to the cylindrical central axis C1 when assembled into the furnace top part 70. As shown in Fig. 6(b) and Fig. 7(c), the first divided cover member 20a and the second divided cover member 20b are formed so that the divided cover side surfaces 14 in the circumferential direction are parallel to each other along the radial direction when assembled into the furnace top part 70. The auxiliary cover member 23a is formed with the auxiliary cover side surface 24 described above.

[0065] 7(c), the auxiliary cover member 23a has a shape corresponding to the gap between the first divided cover member 20a and the second divided cover member 20b when assembled into the furnace top portion 70. That is, the auxiliary cover member 23a is attached so as to cover the gap occurring in the furnace top portion 70.

[0066] As shown in Fig. 6, the first split cover member 20a is formed with a recess 3 for a tap outlet to which a tap outlet 52 can be attached. The first split cover member 20a and the second split cover member 20b are formed with a protrusion 11, which is an engagement portion 2, extending from the outer peripheral wall 6 in the second direction. The auxiliary cover member 23a is not formed with the auxiliary protrusion 27 formed in other embodiments.

[0067] As shown in FIG. 6(b), the convex portions 11 of the first and second split cover members 20a and 20b protrude from the outer peripheral wall 6 toward the left and right sides as shown in the figure, respectively, but do not protrude in the vertical direction as shown in FIG. 7(b). As shown in FIG. 7(b), when the first and second split cover members 20a and 20b are brought into contact with each other at their circumferential side surfaces, the outer contour of the convex portion 11 is formed within the range of the furnace top opening 71. The amount by which the convex portion 11 protrudes from the outer peripheral wall 6 is equal to or less than the depth of the groove portion, which is the engaged portion 65 formed in the furnace body 51. Since the convex portion 11 is formed as described above, the split cover member 20 can be assembled into the furnace top 70 as described below.

[0068] Next, a procedure for assembling the furnace top cover 1a into the furnace top section 70 will be described. As shown in Fig. 4 and Fig. 7(a), the furnace top cover 1a is assembled into the furnace top opening 71 formed by the coil retainer 54 in the furnace top section 70.

[0069] First, as shown in Fig. 7(b), the first split cover member 20a and the second split cover member 20b are inserted into the furnace top opening 71. Next, the first split cover member 20a and the second split cover member 20b are moved in the radial directions of arrows H1 and H2, respectively, to engage the convex portion 11 with the groove portion that is the engaged portion 65, resulting in the state shown in Fig. 7(c).

[0070] Next, the two auxiliary cover members 23a are attached to the gap between the first divided cover member 20a and the second divided cover member 20b. At this time, the auxiliary cover members 23a do not need to be engaged with the groove portion, which is the engaged portion 65 of the furnace body 51, so they can be attached from above in the first direction.

[0071] FIG. 8 shows a cross section II in FIG. 7(b) and a cross section II-II in FIG. 7(c). As shown in FIG. 8(a), the first split cover member 20a and the second split cover member 20b are inserted into the furnace top opening 71 from above and placed on the furnace top 70. Next, as shown in FIG. 8(b), the convex portion 11 is engaged with the groove portion which is the engaged portion 65, and the tapping port 52 is attached to the tapping port recess 3 as shown in FIG. 8(c). In the stage moving from FIG. 8(a) to FIG. 8(b), mortar 53 or the like may be interposed between the bottom surface 5 of the split cover member 20 and the furnace top 70. The mortar 53 is for filling the gap between the bottom surface 5 and the furnace top 70. In addition, an adhesive effect can be expected. Mortar 53 or the like may also be interposed between the auxiliary cover member 23 and the furnace top 70.

[0072] When removing the top cover 1a from the top portion 70, the removal is performed in the reverse order to the procedure described above. That is, first, the auxiliary cover member 23a is removed, then either the first divided cover member 20a or the second divided cover member 20b is moved radially to remove it, and then the other is moved radially to remove it.

[0073] <Effects of the furnace top cover 1a of the first embodiment> The above-described configuration has the following advantages: The furnace top cover 1a includes the first divided cover member 20a, the second divided cover member 20b, and the two auxiliary cover members 23, which cover the entire circumference of the furnace top portion 70, and therefore cracks and lifting of the furnace top portion 70 can be suppressed.

[0074] Moreover, the cover member 10 is easily assembled by simply inserting the two split cover members 20 into the furnace top opening 71 and moving them in the radial directions of the arrows H1 and H2. The directions of the arrows H1 and H2 are 180 degrees opposite each other, so that the angle adjustment during movement is easy. Moreover, the auxiliary cover member 23 can be attached from above in the first direction, so that the assembly is easy.

[0075] In the first embodiment, the furnace cover 1a is described as being provided with the auxiliary cover member 23a, but the auxiliary cover member 23 may be omitted. The circumferential gap between the first divided cover member 20a and the second divided cover member 20b is generated by the amount of movement when the convex portion 11 is engaged with the groove portion, which is the engaged portion 65, and accounts for a small proportion of the gap relative to the entire circumferential direction. Therefore, even if the auxiliary cover member 23 is not present, the furnace cover 1a can suppress cracks and lifting in the furnace top portion 70 throughout the entire circumferential direction.

[0076] In addition, the auxiliary cover member 23a has been described as having auxiliary cover side surfaces 24 whose circumferential side surfaces are parallel to each other along the radial direction, but they do not necessarily have to be parallel. If the gap between the first divided cover member 20a and the second divided cover member 20b is not formed parallel along the radial direction, the auxiliary cover member 23a may be formed to match the shape of the gap. Since the auxiliary protrusion 27 of the other embodiments is not provided, there is no need to move it in the radial direction when assembled, and there is a degree of freedom in the planar shape.

[0077] <Configuration of the furnace top cover 1b of the second embodiment> Next, referring to Fig. 9 to Fig. 11, a furnace top cover 1b of a second embodiment according to the first aspect of the present invention will be described. The furnace top cover 1b differs from the furnace top cover 1a in the configuration of the auxiliary cover member 23. Unlike the auxiliary cover member 23a, the auxiliary cover member 23b has an auxiliary protrusion 27 protruding in the second direction from the auxiliary cover outer peripheral wall 26. The auxiliary protrusion 27 has a shape and dimensions that allow it to be inserted into the groove portion, which is the engaged portion 65 in the furnace body 51. The auxiliary protrusions 27 in the other embodiments are similar.

[0078] As shown in Fig. 9, the furnace top cover 1b includes two auxiliary cover members 23b in addition to the first and second divided cover members 20a and 20b similar to those of the furnace top cover 1a. The two auxiliary cover members 23b are symmetrical with respect to the cylindrical central axis C1 when assembled into the furnace top section 70. The auxiliary cover members 23b are formed with dimensions corresponding to the circumferential gap that occurs when the first and second divided cover members 20a and 20b are assembled into the furnace top section 70. As shown in Fig. 9, the circumferential side surfaces of the auxiliary cover members 23b are the auxiliary cover side surfaces 24, which are parallel to each other and also parallel to the opposing divided cover side surfaces 14.

[0079] The procedure for assembling the auxiliary cover member 23b will be described with reference to Figures 10 and 11. Figures 10(a) and 11(a) are views corresponding to the state of Figure 7(c). The figure shows the state in which the auxiliary cover member 23b is inserted into the furnace top portion 70 from above after the first divided cover member 20a and the second divided cover member 20b are assembled into the furnace top portion 70. Next, the two auxiliary cover members 23b are moved in the directions of arrows U1 and U2 in the radial direction as shown in Figure 10(a), respectively, and the auxiliary protrusions 27 are engaged with the groove portion, which is the engaged portion 65, as shown in Figure 11(b). The auxiliary cover side surfaces 24 of the auxiliary cover member 23b are parallel to each other along the radial direction, so that they can move in the directions of arrows U1 and U2 in the radial direction relative to the gap between the first divided cover member 20a and the second divided cover member 20b.

[0080] Figures 10(b) and 11(b) show the state in which the auxiliary cover member 23b is assembled into the furnace top section 70. The auxiliary cover side surface 24 of the auxiliary cover member 23b is in surface contact with the respective divided cover side surfaces 14 of the first divided cover member 20a and the second divided cover member 20b. The directions of the arrows H1 and H2 shown in Figure 7(b) are perpendicular to the directions of the arrows U1 and U2 shown in Figure 10(a). When removing the furnace top cover 1b from the furnace top section 70, the procedure described above is reversed.

[0081] <Effects of the furnace top cover 1b of the second embodiment> The above-described configuration provides the following effects. As shown in Fig. 10, when the furnace top cover 1b is assembled to the furnace top section 70, the auxiliary cover member 23b fills in the circumferential gaps and engages with the furnace body 51, covering the entire circumferential area without gaps and further suppressing cracks and lifting in the furnace top section 70. Note that the auxiliary cover side surface 24 and the split cover side surface 14 of the auxiliary cover member 23b and the first and second split cover members 20a and 20b do not necessarily need to be in contact with each other, and there may be a gap of a predetermined amount or less that takes into account dimensional errors of each part, deformation such as warping, assembly errors, and the like.

[0082] In addition, the directions of arrows H1 and H2 in which the first and second split cover members 20a and 20b are moved when assembling them are perpendicular to the directions of arrows U1 and U2 in which the auxiliary cover member 23b is moved, making it easy to adjust the angle during construction.

[0083] <Configuration of the furnace top cover 1c of the third embodiment> Next, referring to Fig. 12, a furnace cover 1c of a third embodiment according to the first aspect of the present invention will be described. The furnace cover 1c includes a third divided cover member 20c, a fourth divided cover member 20d, and one auxiliary cover member 23c. The third divided cover member 20c and the fourth divided cover member 20d have different shapes of side surfaces in the circumferential direction from the first divided cover member 20a and the second divided cover member 20b. As shown in Fig. 12(c), the side surfaces in the circumferential direction of the auxiliary cover member 23c are the auxiliary cover side surfaces 24, which are parallel to each other and also parallel to the opposing divided cover side surfaces 14.

[0084] With reference to FIG. 12, the procedure for assembling the top cover 1c into the furnace top 70 will be described. FIG. 12(a) shows the planar shapes of the third and fourth split cover members 20c and 20d. As shown in FIG. 12(b), when the third and fourth split cover members 20c and 20d are inserted into the furnace top opening 71, the circumferential side surfaces of the third and fourth split cover members 20c and 20d do not come into surface contact with each other, but only partially come into contact with each other. As with the first and second split cover members 20a and 20b, the outer contour of the convex portion 11 is formed within the range of the furnace top opening 71. After being inserted into the furnace top opening 71, the third and fourth split cover members 20c and 20d are moved in the radial directions of the arrows H1 and H2, respectively, to engage the convex portion 11 with the groove portion, which is the engaged portion 65.

[0085] Next, as shown in FIG. 12(c), the third split cover member 20c is rotated in the direction of the arrow R1, and the fourth split cover member 20d is rotated in the direction of the arrow R2, so that one of the circumferential side surfaces is in surface contact with the other. At this time, the other circumferential side surfaces are formed to be parallel to each other. Next, the auxiliary cover member 23c is inserted into the gap between the third split cover member 20c and the fourth split cover member 20d, and moved in the direction of the arrow U1 in the radial direction to engage the auxiliary protrusion 27 with the groove portion that is the engaged portion 65. The other circumferential side surface becomes the split cover side surface 14, and is in surface contact with the auxiliary cover side surface 24. The auxiliary cover side surfaces 24 of the auxiliary cover member 23c are parallel to each other. The auxiliary cover member 23c can be moved in the direction of the arrow U1 in the radial direction relative to the gap between the third split cover member 20c and the fourth split cover member 20d, so that the auxiliary protrusion 27 can be engaged with the groove portion that is the engaged portion 65 of the furnace body 51. When removing the furnace top cover 1c from the furnace top portion 70, the above-described procedure is carried out in reverse.

[0086] <Effects of the furnace top cover 1c of the third embodiment> The above-described configuration has the following effects. As shown in FIG. 12, the cover member 10 of the furnace top cover 1c is composed of two split cover members 20 and one auxiliary cover member 23c, so the number of parts is small. In the process of assembling the split cover members 20 into the furnace top section 70, the split cover members 20 are moved in the rotational direction, so that the single auxiliary cover member 23c can fill gaps that occur in the circumferential direction. This reduces the cost of parts management, etc., and reduces the labor required for assembling the split cover members into the furnace top section 70, and can suppress cracks and lifting in the furnace top section 70 in the entire circumferential direction.

[0087] The auxiliary cover member 23c fills the circumferential gap between the third split cover member 20c and the fourth split cover member 20d, and furthermore, the auxiliary protrusion 27 engages with the groove portion which is the engaged portion 65, thereby covering the entire circumferential direction without any gaps, and further suppressing cracks and lifting in the furnace top portion 70. Note that the auxiliary cover side surface 24 and the split cover side surface 14 of the auxiliary cover member 23c, the third split cover member 20c, and the fourth split cover member 20d do not necessarily need to be in contact with each other, and there may be a gap of a predetermined amount or less that takes into account dimensional errors of each part, deformation such as warping, assembly errors, and the like.

[0088] In addition, the assembling work of the auxiliary cover member 23c is performed easily because the directions of arrows H1 and H2, which are used to move the third and fourth split cover members 20c and 20d when assembling them, are perpendicular to the direction of arrow U1, which is used to move the auxiliary cover member 23c, making angle adjustments, etc., during construction easy.

[0089] In the furnace top cover 1a of the first embodiment to the furnace top cover 1c of the third embodiment described above, the split cover members 20 are placed on the furnace top opening 71 at the same time and then assembled, but the present invention is not limited to this. For example, the split cover members 20 may be placed on the furnace top opening 71 one by one in order and assembled into the furnace body 51. In this case, the degree of freedom of the range in which the split cover members 20 can be placed is greater than when multiple split cover members 20 are placed on the furnace top opening 71 at the same time, so the shape of the split cover members 20 in the planar direction may be changed.

[0090] <Configuration of the furnace top cover 1d according to the fourth embodiment> Next, referring to Figures 13 and 14, a fourth embodiment of the furnace cover 1d according to the first aspect of the present invention will be described. As shown in Figure 13, the furnace cover 1d includes a fifth divided cover member 20e, a sixth divided cover member 20f, a seventh divided cover member 20g, and one auxiliary cover member 23d. The fifth divided cover member 20e to the seventh divided cover member 20g are all fan-shaped. As shown in Figure 14(c), the circumferential side surfaces of the auxiliary cover member 23d are the auxiliary cover side surfaces 24, which are parallel to each other and also parallel to the opposing divided cover side surfaces 14.

[0091] The furnace top cover 1d differs from the other embodiments already described in the movement direction when the split cover member 20 is assembled. The procedure for assembling the furnace top cover 1d to the furnace top section 70 will be described with reference to FIG. 14(a). First, as shown in FIG. 14(a), the fifth split cover member 20e is inserted into the furnace top section opening 71 and moved in the direction of the arrow D1 in the radial direction to engage the convex portion 11 with the groove portion that is the engaged portion 65. Next, as shown in FIG. 14(b), the sixth split cover member 20f is inserted into the furnace top section opening 71 while tilting it and moved in the direction of the arrow D2 in the radial direction to engage the convex portion 11 with the groove portion that is the engaged portion 65.

[0092] 14(c), the sixth split cover member 20f is rotated in the direction of arrow R1 so that the circumferential side surface comes into contact with the fifth split cover member 20e. Next, the seventh split cover member 20g is inserted into the furnace top opening 71 at an angle, and then moved in the radial direction of arrow D3 so that the protrusion 11 engages with the groove portion that is the engaged portion 65. Next, the seventh split cover member 20g is rotated in the direction of arrow R2 so that the circumferential side surface comes into contact with the fifth split cover member 20e.

[0093] Furthermore, auxiliary cover member 23d is inserted into the gap between sixth divided cover member 20f and seventh divided cover member 20g, and while moving it in the radial direction of arrow H2, auxiliary protrusion 27 is engaged with the groove portion which is engaged portion 65. As shown in Fig. 14(c), auxiliary cover member 23d, like auxiliary cover member 23b and auxiliary cover member 23c, includes auxiliary cover outer peripheral wall 26, auxiliary protrusion 27, and auxiliary cover side surface 24. Since auxiliary cover side surface 24 of auxiliary cover member 23d are parallel to each other along the radial direction, it is movable in the radial direction of arrow H2 relative to the gap between sixth divided cover member 20f and seventh divided cover member 20g.

[0094] <Effects of the furnace top cover 1d of the fourth embodiment> The above-described configuration provides the following effects. As shown in Fig. 14, the split cover member 20 and the auxiliary cover member 23d of the top cover 1d can be assembled while moving them in the diagonal radial directions from arrow D1 to arrow D3 and in the direction of arrow H2, respectively, to cover the top section 70 without any gaps in the circumferential direction. Therefore, the top cover 1d can suppress cracks and lifting in the top section 70 in the entire circumferential direction. The gap between the auxiliary cover side surface 24 of the auxiliary cover member 23d and the split cover side surface 14 of the split cover member 20 in the circumferential direction is the same as that of the top cover 1b and the top cover 1c.

[0095] <Configuration of the furnace top cover 1e according to the fifth embodiment> Next, a fifth embodiment of the top cover 1e will be described with reference to Figures 15 to 17. The top cover 1e differs from the top cover 1b in the following respects. In the top cover 1e, the auxiliary cover member 23e has an auxiliary side protrusion 28 that protrudes in the second direction from the auxiliary cover side surface 24. The eighth split cover member 20h and the ninth split cover member 20j have a split cover recess 29 on the split cover side surface 14. When the auxiliary cover member 23e is moved radially with the eighth split cover member 20h and the ninth split cover member 20j assembled to the top section 70, the auxiliary side protrusion 28 can engage with the split cover recess 29.

[0096] As shown in Fig. 15, auxiliary side protrusion 28 is formed at the same height in the first direction as auxiliary protrusion 27, and is formed in a rib shape along the second direction. As shown in Fig. 15 and Fig. 17, split cover recess 29 is formed in a groove shape so that auxiliary side protrusion 28 can be engaged therewith.

[0097] The procedure for attaching the auxiliary cover member 23e will be described with reference to Figures 16 and 17. The auxiliary cover member 23e has an auxiliary-side protrusion 28 formed on the auxiliary cover member 23b, so there are restrictions when attaching it from the first direction. As shown in Figures 16(a) and 17(a), when attaching the auxiliary cover member 23e from the top to the bottom in the first direction, it is necessary to insert it into an area where the eighth divided cover member 20h and the ninth divided cover member 20j are not present, i.e., inside the inner circumferential wall 8.

[0098] One of the two auxiliary cover members 23e is inserted to the height of the furnace top 70, and then moved in the radial direction U1 while inserting the auxiliary side protrusion 28 into the split cover recess 29. Next, the other auxiliary cover member 23e is inserted in the same manner and moved in the radial direction U2. Depending on the dimensional relationship between the inner peripheral wall 8 and the auxiliary cover member 23c, it may be necessary to attach each of the two auxiliary cover members 23e one by one. To remove the auxiliary cover member 23e and the eighth and ninth split cover members 20h and 20j from the furnace top 70, the procedure described above can be carried out in reverse.

[0099] In addition, an example has been shown in which the auxiliary side convex portion 28 is formed in the auxiliary cover member 23e and the split cover concave portion 29 is formed in the eighth split cover member 20h, etc., compared to the top cover 1b, but it may also be formed in any of the other embodiments, such as the top cover 1a, top cover 1c, and top cover 1d.

[0100] <Effects of the furnace top cover 1e of the fifth embodiment> The above-described configuration provides the following effects. When the eighth and ninth divided cover members 20h and 20j are assembled to the furnace top section 70, the auxiliary cover member 23e can be moved radially so that the auxiliary side protrusions 28 can engage with the eighth and ninth divided cover members 20h and 20j. Thus, by integrating the auxiliary cover member 23e with the eighth and ninth divided cover members 20h and 20j, cracks and lifting of the furnace top section 70 can be further suppressed.

[0101] <Configuration of the furnace top cover 1f of the sixth embodiment> Next, referring to Figures 18 and 19, a furnace top cover 1f of a sixth embodiment according to the first aspect of the present invention will be described. The furnace top cover 1f has a configuration different from other embodiments. The engagement portion 2 of the furnace top cover 1f includes an engagement recess 21 and an engagement member 22. As shown in Figures 18 and 19(b), the engagement recess 21 is a recess formed from the outer peripheral wall 6 to the middle of the inner peripheral wall 8 of the cover member 10f in the second direction. The engagement member 22 can engage with the engagement hole, which is the engaged portion 66 formed penetrating from the outer peripheral surface to the inner peripheral surface of the furnace body 51 in the second direction, and the engagement recess 21.

[0102] 18, the engaging member 22 is, for example, a bolt. The engaging recess 21 is, for example, formed with a female thread into which the bolt can be screwed. The engaging member 22 may be a press-fit pin other than a bolt. In that case, the engaging recess 21 is formed with a hole diameter that holds the press-fit pin.

[0103] The procedure for assembling the top cover 1f into the top section 70 will be described. First, the top cover 1f is inserted into the top opening 71 from above in the first direction. Next, as shown in FIG. 18, the engaging member 22 is engaged with the engaging hole and engaging recess 21, which are the engaged portion 66 of the furnace body 51. Next, the tapping hole 52 is attached to the tapping hole recess 3. The top cover 1f can be removed from the top section 70 by removing the engaging member 22 from the engaging recess 21 and the engaging hole, which is the engaged portion 66. By removing the top cover 1f from the top section 70, the inside of the induction furnace 50e can be opened and internal parts can be replaced, repaired, etc.

[0104] <Effect of the furnace top cover 1f of the sixth embodiment> The above-described configuration provides the following effects. The furnace top cover 1f can be engaged with the furnace body 51 and the engagement recess 21 by inserting the engagement member 22 from the outer peripheral surface of the furnace body 51, so that cracks and lifting of the furnace top part 70 can be suppressed by simple construction work. In addition, the furnace top cover 1f can be easily removed from the furnace top part 70, so that parts inside the furnace body 51 can be easily replaced and internal repairs can be easily performed. Furthermore, since the engagement recess 21 is a recess that opens from the outer peripheral wall 6 and is formed halfway through the inner peripheral wall 8, even if the engagement member 22 is made of metal, it does not come into contact with the molten metal in the furnace, so induction heating is reduced. The engagement member 22 may be made of non-metallic material such as ceramics.

[0105] <Configuration of induction furnace 50> Next, an induction furnace 50 according to a second aspect of the present invention will be described. As already explained, the induction furnace 50 includes a furnace top cover 1, a furnace body 51, a sleeve material 55 installed inside the furnace body 51, a back material 56 which is an unshaped refractory material filling the gap between the coil cement 58 forming the inner circumference of the furnace body 51 and the sleeve material 55, and a tapping hole 52, as shown in FIG. 2 etc. Note that the furnace top cover 1 includes the furnace top cover 1a to the furnace top cover 1f of all the embodiments.

[0106] At least a portion of the top cover 1 is fitted between the sleeve material 55 and the tap hole 52. When the engaging portion 2 engages with the engaged portions 65, 66 formed on the furnace body 51, the top cover 1 is restricted from moving relative to the furnace body 51 in the first direction. When the engaging portion 2 is released from the engaged state with the engaged portion 65 or the engaged portion 66, the top cover 1 can be separated from the furnace body 51 together with the tap hole 52, and the sleeve material 55 can be removed from inside the furnace body 51.

[0107] <Effect of the configuration of induction furnace 50> The above-described configuration provides the following advantages. When the engaging portion 2 of the induction furnace 50 engages with the engaged portions 65, 66 formed on the furnace body 51, the relative movement of the furnace top cover 1 with respect to the furnace body 51 in the first direction is restricted. This makes it possible to suppress cracks and lifting of the furnace top portion 70.

[0108] Furthermore, in the induction furnace 50, when the engaging portion 2 is released from the engaged state with the engaged portions 65, 66, the furnace top cover 1 can be separated from the furnace body 51 together with the tapping port 52, and the sleeve material 55 can be removed from inside the furnace body 51. Therefore, repair work inside the furnace body 51 or replacement of internal parts can be easily performed. [Explanation of symbols]

[0109] 1, 1a, 1b, 1c, 1d, 1e, 1f Furnace cover 2 Engagement part 3. Tap hole recess 5 Bottom 6 Outer wall 7 aperture 8 Inner wall 10, 10f Cover member 11 Convex 14 Split cover side 20 Split cover member 21 Engagement recess 22 Engagement member 23, 23a, 23b, 23c, 23d, 23e Auxiliary cover members 24 Auxiliary cover side 26 Auxiliary cover outer wall 27 Auxiliary protrusion 28 Auxiliary side convex part 29 Split cover recess 50, 50a, 50e induction furnace 51 Furnace body 52 Tap hole 55 Sleeve material 65 Engaged part 66 Engaged part 70 Furnace top C1 Cylinder central axis C2 Opening center axis

Claims

1. It can be installed in the top of a cylindrical induction furnace, A cover member; At least a portion of the cover member is provided with an engaging portion that can be engaged with an engaged portion of a furnace body of the induction furnace, The cover member is a recess for a tapping outlet into which a tapping outlet can be attached; A bottom surface which is a surface to be placed on the top of the furnace; In the state where the furnace top is installed, An outer peripheral wall facing the inner peripheral surface of the furnace body; An inner circumferential wall defining an opening; The cover member is formed of a shaped refractory material, a cylindrical central axis of the induction furnace and a central axis of the opening of the opening are substantially collinear; A direction along the cylinder central axis is a first direction, and a direction perpendicular to the first direction is a second direction, The engagement portion is located at least between the tap hole recess and the bottom surface, When the engaging portion engages with the furnace body, the relative movement in the first direction with respect to the furnace body is restricted, A furnace top cover that can be separated from the furnace body when the engagement portion moves away from the furnace body, thereby opening the inside of the induction furnace.

2. The cover member includes a divided cover member divided into a plurality of parts in a circumferential direction around the opening central axis, The engaging portion is a convex portion protruding in the second direction from the outer circumferential wall of each of the split cover members, A furnace top cover as described in claim 1, wherein each of the split cover members can be moved in different directions in a radial direction centered on the cylindrical central axis, so that the convex portion can engage with the engaging portion formed on the inner surface of the furnace body.

3. When the split cover member is assembled into the furnace top portion, An auxiliary cover member is provided which is attached to a gap generated between adjacent split cover members in the circumferential direction and covers a part of the furnace top portion, The furnace top cover according to claim 2 , wherein the auxiliary cover member is formed of a shaped refractory material, and at least a portion of the auxiliary cover member is in contact with the divided cover members adjacent in the circumferential direction or has a gap of a predetermined amount or less.

4. A furnace top cover as described in claim 3, wherein when the auxiliary cover member is assembled into the furnace top portion, the circumferential side surfaces are auxiliary cover side surfaces that are parallel to each other along the radial direction.

5. With the auxiliary cover member and the split cover member assembled to the furnace top portion, In the circumferential direction, a split cover side surface of the split cover member adjacent to and facing the auxiliary cover member is parallel to the auxiliary cover side surface, The furnace top cover according to claim 4 , wherein the auxiliary cover side surface and the divided cover side surface are in contact with each other including surface contact or have a gap of a predetermined amount or less.

6. The auxiliary cover member is An auxiliary cover outer peripheral wall that faces the inner peripheral surface of the furnace body when assembled to the furnace top portion; an auxiliary protrusion protruding from an outer peripheral wall of the auxiliary cover in the second direction; The furnace top cover as described in claim 5, wherein the auxiliary cover member is capable of engaging with the engaging portion formed on the inner surface of the furnace body by moving the auxiliary cover member in the radial direction while the split cover member is assembled to the furnace top portion, so that the auxiliary convex portion can engage with the engaging portion formed on the inner surface of the furnace body.

7. The auxiliary cover member includes an auxiliary side protrusion protruding in the second direction on a side surface of the auxiliary cover, The split cover member includes a split cover recess on a side surface of the split cover, The furnace top cover as described in claim 6, wherein the auxiliary cover member is capable of engaging with the auxiliary side convex portion in the split cover concave portion by moving the auxiliary cover member in the radial direction while the split cover member is assembled in the furnace top portion.

8. The engaging portion includes an engaging recess and an engaging member. The engagement recess is a recess formed from the outer circumferential wall to a middle of the inner circumferential wall of the cover member in the second direction, A furnace top cover as described in claim 1, wherein the engaging member is capable of engaging with the engaged portion formed penetrating from the outer peripheral surface to the inner peripheral surface of the furnace body in the second direction, and with the engaging recess.

9. A furnace top cover according to any one of claims 1 to 8; The furnace body, A sleeve material installed inside the furnace body; A castable refractory material filling a gap between the inner periphery of the furnace body and the sleeve material; The tapping hole is provided, At least a portion of the furnace top cover is fitted between the sleeve material and the tap hole, When the engaging portion is engaged with the engaged portion, The furnace top cover is restricted in its relative movement in the first direction with respect to the furnace body, When the engaging portion is released from the engaged state with the engaged portion, The induction furnace has a top cover that can be separated from the furnace body together with the tapping port, and the sleeve material can be removed from inside the furnace body.

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