Electric furnace unit and electric furnace

Abstract

To provide electric furnace units and an electric furnace which enable flexible design and partial exchange after installation of an electric furnace.SOLUTION: Electric furnace units (10) form a side face of an electric furnace (1) by being laminated, and comprise: two first side face parts (101) facing each other in a first direction (x axis direction) vertical to a lamination direction; and two second side face parts (102) connected with the two first side face parts (101) and provided with electric heaters inside the furnace.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an electric furnace unit and an electric furnace. [Background technology]

[0002] Electric heaters are sometimes used as the heat source of heat treatment furnaces for heat-treating glass, ceramics, and various metal materials. An electric heater generates heat when an electric current flows through it, and includes a pair of heater terminals and a heating element such as a heating wire connected between the heater terminals. A furnace whose heat source is an electric heater is called an electric furnace.

[0003] For example, Patent Document 1 discloses a diffusion furnace having a configuration in which vertical or spiral grooves are provided on the inner surface of a cylindrical furnace, and electric heating wires such as nichrome wires formed in a wavy shape or in a spiral shape along the inner surface of the furnace are arranged in these grooves. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2004 / 049414 Summary of the Invention [Problem to be solved by the invention]

[0005] Conventional electric furnaces are designed to have their own size and cannot flexibly accommodate design changes. Also, when a heating element of a conventional electric furnace breaks down, the entire furnace needs to be repaired.

[0006] An object of the present disclosure, made in consideration of the above circumstances, is to provide an electric furnace unit and an electric furnace that enable flexible design and partial replacement after the electric furnace is installed. [Means for solving the problem]

[0007] An electric furnace unit according to one embodiment of the present disclosure includes: An electric furnace unit that is stacked to form a side surface of an electric furnace, Two first side surface portions opposed to each other in a first direction perpendicular to the stacking direction; and two second side portions connected to the two first side portions and provided with electric heaters on the inside of the furnace.

[0008] Moreover, an electric furnace according to an embodiment of the present disclosure includes: The electric furnace unit is constructed by stacking the above electric furnace units. Effect of the Invention

[0009] According to the present disclosure, it is possible to provide an electric furnace unit and an electric furnace that allow for flexible design and partial replacement after the electric furnace is installed. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram showing a configuration example of an electric furnace according to one embodiment. [Diagram 2] FIG. 2 is a diagram showing a configuration example of a portion of an electric furnace unit according to one embodiment. [Diagram 3] FIG. 3 is a diagram showing a configuration example of a portion of an electric furnace unit according to one embodiment. [Figure 4] FIG. 4 is a diagram showing a configuration example of a portion of an electric furnace unit according to one embodiment. [Diagram 5] FIG. 5 is a diagram showing a configuration example of a portion of an electric furnace unit according to one embodiment. [Figure 6] FIG. 6 is a diagram showing a configuration example of a portion of an electric furnace unit according to one embodiment. [Figure 7] FIG. 7 is a diagram for explaining a replaceable electric heater. [Figure 8A] FIG. 8A is a diagram for explaining a method for fixing a replaceable electric heater. [Figure 8B] FIG. 8B is a diagram for explaining a method for fixing a replaceable electric heater. [Figure 9A]FIG. 9A is a diagram for explaining a hanger pin that reduces deformation. [Figure 9B] FIG. 9B is a diagram for explaining a hanger pin that reduces deformation. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an electric furnace unit and an electric furnace according to an embodiment of the present disclosure will be described with reference to the drawings. In each drawing, the same or corresponding parts are given the same reference numerals. In the description of this embodiment, the description of the same or corresponding parts will be omitted or simplified as appropriate.

[0012] Fig. 1 is a schematic diagram showing a configuration example of an electric furnace 1 according to this embodiment. The left diagram in Fig. 1 shows the side of the electric furnace 1. The electric furnace 1 further has a bottom and a top, and the inside is heated by a heater to a high temperature (1200°C as an example). The heat source of the electric furnace 1 is an electric heater 11 (see Fig. 3).

[0013] In this embodiment, the electric furnace 1 heats chemical products. However, the electric furnace 1 may heat-treat products or materials other than chemical products (e.g., metal materials). The width W of the electric furnace 1 is, for example, 1.5 m. The depth D of the electric furnace 1 is, for example, 2.2 m. The height Ht of the side of the electric furnace 1 is, for example, 12.6 m. However, the width W, depth D, and height Ht of the electric furnace 1 are not limited to these values.

[0014] Here, as shown in Fig. 1, Cartesian coordinates corresponding to the width, depth, and height directions of the electric furnace 1 are set. The z-axis direction is a direction parallel to the height direction of the electric furnace 1 and corresponds to the stacking direction described below. The x-axis direction is a first direction perpendicular to the z-axis direction (stacking direction) and corresponds to the width direction of the electric furnace 1. The y-axis direction is a second direction perpendicular to the stacking direction and the first direction and corresponds to the depth direction of the electric furnace 1.

[0015] In the following, positional relationships may be explained using the terms x-axis, y-axis, and z-axis. In addition, in the drawings from Figure 2 onwards, the viewpoint direction is indicated using the same Cartesian coordinates as in Figure 1.

[0016] 1, the electric furnace 1 according to this embodiment is configured by stacking electric furnace units 10. The stacking direction, i.e., the direction in which the electric furnace units 10 are piled up, is the height direction of the electric furnace 1 (z-axis direction).

[0017] The height Hu of the electric furnace unit 10 is, for example, 2.1 m. The side of the electric furnace 1 is formed by stacking, for example, six electric furnace units 10. However, the height Hu of the electric furnace unit 10 is not limited to this value. Furthermore, the number of electric furnace units 10 stacked is not limited to a specific number. The width W and depth D of the electric furnace unit 10 are the same as those of the electric furnace 1.

[0018] The electric furnace unit 10 has two first side portions 101 facing each other in a first direction (x-axis direction). The electric furnace unit 10 also has two second side portions 102 connected to the two first side portions 101 and provided with electric heaters 11 on the inside of the furnace. The two second side portions 102 face each other in a second direction (y-axis direction). The detailed configurations of the first side portion 101 and the second side portion 102 will be described later.

[0019] Since the electric furnace 1 according to this embodiment is constructed by stacking electric furnace units 10 having the same structure, the height Ht can be flexibly changed in units of the height Hu of the electric furnace unit 10. Therefore, flexible design is possible even when changes are made midway.

[0020] In addition, since the electric furnace units 10 have the same structure, if a failure occurs in the electric heater 11 of the electric furnace 1 after installation, it is possible to replace the failed electric furnace unit 10. In other words, partial replacement is possible after the electric furnace 1 is installed.

[0021] The electric furnace unit 10 will be described in detail below. Figures 2 to 6 are diagrams showing examples of the configuration of a portion of the electric furnace unit 10.

[0022] FIG. 2 is a view of the second side portion 102 of the electric furnace unit 10 from the outside of the furnace toward the inside of the furnace (specifically, toward the positive direction of the y-axis). FIG. 3 is a view of the second side portion 102 of FIG. 2 from the inside of the furnace toward the outside of the furnace (specifically, toward the negative direction of the y-axis). FIG. 4 is a view of a part of the electric furnace unit 10 including the second side portion 102 of FIG. 2, viewed from above to below in the stacking direction (toward the negative direction of the z-axis). FIG. 5 is a view of a cross section including the hanging ring 20 of the second side portion 102 of FIG. 2, viewed toward the negative direction of the x-axis. FIG. 6 is a view of a cross section including the condensation receiver 24 of the second side portion 102 of FIG. 2, viewed in the opposite direction to FIG. 5 (toward the positive direction of the x-axis). In the following description, FIG. 2 to FIG. 6 are appropriately referred to.

[0023] As shown in Fig. 3, the electric furnace unit 10 is provided with an electric heater 11 on the furnace inner side of the second side portion 102. The electric heater 11 generates heat when a current of, for example, 400 A flows through it. The heating element of the electric heater 11 may be made of, for example, an Fe-Cr-Al alloy. Since the heating element of the electric heater 11 is made of an Fe-Cr-Al alloy having high oxidation resistance, surface oxidation when used at high temperatures in an air atmosphere can be suppressed, and heat generation stability and durability can be improved.

[0024] As the Fe-Cr-Al based alloy, for example, Pyromax (registered trademark) "PX-D", "PX-DS", "PX-C" and "PX-PMD" manufactured by Riken Environmental Systems Co., Ltd. can be used.

[0025] Here, the above "PX-D" is an Fe-Cr-Al alloy containing 23 wt% Cr and 5.5 wt% Al. The above "PX-DS" is an Fe-Cr-Al alloy containing 23 wt% Cr and 6 wt% Al. The above "PX-C" is an Fe-Cr-Al alloy containing 26 wt% Cr and 7.5 wt% Al. The above "PX-PMD" is an Fe-Cr-Al alloy containing 23 wt% Cr, 6.0 wt% Al, and other trace elements, and is manufactured using powder metallurgy and hot extrusion processing.

[0026] The second side portion 102 comprises a unit frame 12 which forms the surface on the outside of the furnace, and a heat insulating material 13 provided between the unit frame 12 and the electric heater 11. The unit frame 12 is a plate-shaped part made of metal such as iron. The heat insulating material 13 suppresses the transfer of heat to the outside of the furnace in order to retain the heat generated by the electric heater 11 inside the furnace. The heat insulating material 13 may be an inorganic fiber heat insulating material (cotton-like ceramic fiber as an example), but is not limited to a specific material as long as it can withstand use at high temperatures.

[0027] Here, the heat insulating material 13 is omitted in Fig. 3, but as shown in Fig. 5, the heat insulating material 13 is provided without any gap between the unit frame 12 and the electric heater 11. The heat insulating material 13 has a thickness of 300 mm as an example, but is not limited to this value.

[0028] 3, the electric heater 11 is fixed by a hanger pin 14 inserted into the thermal insulation material 13, and is bent at the position of the hanger pin 14. By bending the electric heater 11 at the position of the hanger pin 14, the length of the heating element is ensured within the limited surface of the second side portion 102, and sufficient heat is generated to heat the inside of the furnace to a high temperature.

[0029] Here, the hanger pin 14 may be made of the above-mentioned "PX-D", "PX-PMD", etc., which have high resistance to deformation due to heat. The hanger pin 14 may also be made of SUS (Steel Use Stainless).

[0030] As described above, a high current of, for example, 400 A flows through the electric heater 11. Therefore, unlike the case where a gas heater or the like is used, a leakage current prevention measure is required to prevent the current flowing inside the furnace from leaking outside the furnace.

[0031] 5 and 6, in this embodiment, the second side portion 102 includes an insulating plate 16 between the unit frame 12 and the hanger pin 14. The insulating plate 16 is attached to the furnace inner side of the unit frame 12 by a mounting plate 17 according to the position of the hanger pin 14. The insulating plate 16 is made of an insulator and prevents current from leaking outside the furnace via the hanger pin 14.

[0032] Furthermore, the hanger pin 14 may be inserted into the insulation material 13 via an insulating hanger 15 (insulating washer). The insulating hanger 15 is made of an insulator. Even if a leakage current occurs, the leakage current does not enter the insulation material 13 due to the insulating hanger 15, but flows along the end of the hanger pin 14 located inside the furnace from the insulating hanger 15, and then flows through the surface portion inside the furnace. This configuration of the second side portion 102 makes it possible to prevent the current from leaking outside the furnace via the hanger pin 14.

[0033] Here, as described above, the heat insulating material 13 may be, for example, cotton-like ceramic fiber. Air heated by the heat in the furnace may cool inside the heat insulating material 13, causing condensation. If the heat insulating material 13 contains a large amount of moisture, there is a risk that the electric current flowing through the furnace may leak outside the furnace through the heat insulating material 13.

[0034] As shown in Fig. 6, in this embodiment, the second side portion 102 is provided with a condensation receiver 24 that is inserted into the insulation 13 and exposed outside the furnace. Condensation generated inside the insulation 13 flows down the condensation receiver 24 to the outside of the furnace and then flows down the wall outside the furnace. In other words, condensation generated inside the insulation 13 is discharged to the outside of the furnace by the condensation receiver 24. Therefore, the insulation 13 does not contain a large amount of moisture inside, and electric leakage through the insulation 13 can be prevented.

[0035] Here, the condensation receiver 24 may be made of metal such as stainless steel, and is disposed inside the insulation material 13 so as not to come into contact with the hanger pins 14. The insulation material 13 may be divided into a plurality of blocks in accordance with the shape of the electric heater 11. In this case, it is preferable to insert an individual condensation receiver 24 into each of the divided blocks of the insulation material 13 in order to enhance the effect of condensation discharge.

[0036] 2 and 6, the heater terminal 21 is exposed outside the furnace at the second side portion 102. The heater terminal 21 is electrically connected to an end of the electric heater 11. The heater terminal 21 and the end of the electric heater 11 may be connected via a conductor passing through the inside of the thermal insulation material 13.

[0037] The heater terminals 21 are connected to electrical wiring 23 outside the electric furnace 1 using crimp terminals 22. In other words, the electric heater 11 can be wired in the air by using the heater terminals 21 exposed outside the furnace. With this configuration of the electric furnace unit 10, when replacing a broken portion of the electric furnace unit 10, the effort of rewiring is reduced and repairs can be made quickly.

[0038] 4, the first side portion 101 of the electric furnace unit 10 may be configured by removing components related to the electric heater 11 from the second side portion 102. Specifically, the first side portion 101 includes a furnace body frame 18 that is the surface on the outside of the furnace, and a heat insulating material 13 provided on the furnace inside of the furnace body frame 18.

[0039] The furnace body frame 18 corresponds to the unit frame 12 of the second side portion 102, and may be a plate-shaped part made of metal such as iron. The furnace body frames 18 of the two opposing first side portions 101 and the unit frames 12 of the two opposing second side portions 102 form a skeleton of the electric furnace unit 10. The skeleton supports the electric furnace units 10 stacked on top and the top. Of the furnace body frame 18 and the unit frame 12 that form the skeleton, the furnace body frame 18 may be configured to have a higher strength than the unit frame 12. As an example, the furnace body frame 18 may be formed thicker than the unit frame 12.

[0040] Further, the heat insulating material 13 on the first side surface portion 101 and the heat insulating material 13 on the second side surface portion 102 surround the electric heater 11 and the space inside the furnace from all sides, forming an airtight structure that maintains the temperature inside the furnace.

[0041] The electric furnace unit 10 may be provided with an attachment rib 19 at the connection between the furnace body frame 18 and the unit frame 12. The attachment rib 19 fits with a part provided at the bottom of the electric furnace unit 10 or the top part stacked on top. This allows easy positioning when assembling the electric furnace 1 (stacking the electric furnace units 10).

[0042] 5, a hanging ring 20 may be provided on the furnace body frame 18 or the unit frame 12. The hanging ring 20 has a shape that allows it to be easily hung by, for example, the hook of a crane. In other words, by providing the hanging ring 20, the electric furnace unit 10 can be easily lifted and moved by a crane. Such a configuration of the electric furnace unit 10 allows the assembly of the electric furnace 1 to proceed efficiently.

[0043] As described above, the electric furnace unit 10 and the electric furnace 1 according to the present embodiment have the above-mentioned configuration, which allows for flexible design and partial replacement of the electric furnace after installation.

[0044] Although the embodiments of the present disclosure have been described based on the drawings and examples, it should be noted that those skilled in the art can easily make various modifications or corrections based on the present disclosure. Therefore, it should be noted that these modifications and corrections are included in the scope of the present disclosure.

[0045] For example, the hanger pin 14 may have a function not only to fix and bend the electric heater 11, but also to compress and fix the heat insulating material 13 to the outside of the furnace. By compressing the heat insulating material 13, the sealing effect (thermal insulation) that maintains the temperature inside the furnace can be improved.

[0046] The heat insulating material 13 may be constructed by stacking a plurality of heat insulating material parts (for example, heat insulating material 13 formed into blocks) in the z-axis direction. In this case, the upper and lower heat insulating material parts may have a step or the like for fitting into each other, making it easy to position them. When the heat insulating material parts are stacked, they may be compressed in the z-axis direction to further improve the heat insulating properties.

[0047] Also, the hanger pin 14 may be configured so that the electric heater 11 is replaceable. FIG. 7 is a diagram for explaining a replaceable electric heater 11. First, as a method for providing the electric heater 11 in the furnace, a ceramic material 31 and an insulating hanger 15 may be attached to the hanger pin 14, and the electric heater 11 may be suspended, so that the electric heater 11 and the furnace body are insulated from each other. Then, in order to fix the position of the electric heater 11, a removable fixing pin 32 may be used at the end of the hanger pin 14 on the inside of the furnace. The electric heater 11 may deteriorate or deform due to long-term use at high temperatures, but the configuration of the hanger pin 14 using the fixing pin 32 allows only the electric heater 11 to be replaced, thereby reducing costs. Also, the fixing pins 32 may be configured so that the fixing pins 32 are connected to each other between adjacent hanger pins 14. In this case, the rotation of the hanger pins 14 can be prevented. Here, as shown in FIG. 8A, a cap 33 may be used instead of the fixing pin 32. The cap 33 has a screw inside. Also, as shown in Fig. 8B, a lock washer 34 may be used. Here, Fig. 8A and Fig. 8B correspond to partial area PA in Fig. 7. In this way, the hanger pin 14 has a removable member (specific examples include the fixing pin 32, the cap 33, or the lock washer 34) for fixing the position of the electric heater 11 inside the furnace, so that only the electric heater 11 can be replaced.

[0048] 9A and 9B, the hanger pin 14 may have a reinforcing member 35 therein to further reduce deformation. The reinforcing member 35 is, for example, ceramic (specific examples of materials include alumina, mullite, SiC, and zirconia), but is not limited thereto. The position of the reinforcing member 35 inserted into the hanger pin 14 is fixed by a metal cover 36 so as not to move. As shown in FIG. 9A, the reinforcing member 35 may be inserted into the entire hanger pin 14. As shown in FIG. 9B, the reinforcing member 35 may be inserted into a part of the hanger pin 14 (specific example, only the inside of the furnace). [Explanation of symbols]

[0049] 1 Electric furnace 10 Electric furnace unit 11 Electric heater 12 Unit Slots 13. Insulation 14 Hanger pin 15 Insulating Hanger 16 Insulating plate 17 Mounting plate 18 Furnace frame 19 Mounting rib 20 Hanging Rings 21 Heater terminal 22 Crimp terminal 23 Electrical wiring 24 Condensation catcher 31 Ceramic Materials 32 Fixing pin 33 Cap 34 Lock washer 35 Reinforcement members 36 metal lid 101 first side portion 102 Second side part

Claims

1. An electric furnace unit that is stacked to form a side surface of an electric furnace, Two first side surface portions opposed to each other in a first direction perpendicular to the stacking direction; and two second side portions connected to the two first side portions and having electric heaters provided inside the furnace.

2. The second side portion includes a unit frame that is a surface on the outside of the furnace, and a heat insulating material provided between the unit frame and the electric heater, 2. The electric furnace unit according to claim 1, wherein the electric heater is fixed by a hanger pin inserted into the insulating material and is bent at the position of the hanger pin.

3. The electric furnace unit according to claim 2 , wherein the second side portion includes an insulating plate between the unit frame and the hanger pin.

4. The electric furnace unit according to claim 2 or 3, wherein the second side portion is provided with a condensation receiver that is inserted into the insulation material and exposed outside the furnace.

5. 4. The electric furnace unit according to claim 2 or 3, wherein the second side portion is provided with a heater terminal exposed outside the furnace and electrically connected to an end of the electric heater.

6. The first side portion includes a furnace body frame that is a surface on the outside of the furnace, and a heat insulating material provided on the furnace inside of the furnace body frame, 4. The electric furnace unit according to claim 2 or 3, wherein a hanging ring is provided on the furnace body frame or the unit frame.

7. 4. The electric furnace unit according to claim 2, wherein the hanger pin has a removable member for fixing the position of the electric heater inside the furnace.

8. 4. The electric furnace unit according to claim 2 or 3, wherein the hanger pin has a reinforcing member therein.

9. An electric furnace constructed by stacking the electric furnace units according to any one of claims 1 to 3.

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