heating furnace

Abstract

When heat-treating a powdered material by inserting a ceramic inner tube into a metal heating tube, the reduction in the amount of material recovered from the heating furnace is suppressed. [Solution] The heating furnace 1 comprises a heating tube 10, an inner tube 15, a biasing member 65, and stoppers 68 and 69. The heating tube 10 is made of a metal material. The inner tube 15 is placed inside the heating tube 10. The inner tube 15 has a transport space 15a formed inside through which the workpiece A is transported. The inner tube 15 is made of a ceramic material. The biasing member 65 is placed on at least one of the longitudinal sides of the inner tube 15. The biasing member 65 biases the inner tube 15 in the longitudinal direction. The stoppers 68 and 69 restrict the inner tube 15 from separating from the heating tube 10.

Description

Technical Field

[0001] The present invention relates to a heating furnace.

Background Art

[0002] Japanese Patent Application Laid-Open No. 2016-38140 discloses a rotary kiln in which tires are provided on the outer peripheral portions of one end and the other end of a rotating cylinder, and each tire is placed on a roller so that the rotating cylinder can rotate and is installed substantially horizontally, and the processing raw material introduced into the rotating cylinder is heated from the outside of the rotating cylinder. The rotating cylinder includes an outer cylinder made of heat-resistant steel, an inner cylinder formed by connecting a plurality of short cylindrical bodies made of ceramics or graphite, and a C-ring having a right-angled triangular cross-sectional shape. A plurality of ring grooves are formed on the inner peripheral surface of the outer cylinder. A male screw and a ring groove are formed on the outer peripheral surface of one end of each short cylindrical body. The ring groove formed in the short cylindrical body is adjacent to the male screw. The ring groove of the short cylindrical body has a right-angled triangular cross-sectional shape. The hypotenuse of this right-angled triangle forms the bottom surface of the ring groove of the short cylindrical body. The depth of the ring groove of the short cylindrical body gradually decreases from one end side to the other end side. A female screw is formed on the inner peripheral surface of the other end of each short cylindrical body. By screwing the male screw of one short cylindrical body into the female screw of another short cylindrical body, a plurality of short cylindrical bodies are connected to form an inner cylinder. The C-ring is fitted into the ring groove of the outer cylinder so that the bottom side in the right-angled triangular cross-sectional shape of the C-ring abuts against the bottom surface of the ring groove of the outer cylinder. The inner cylinder is fitted into the outer cylinder. The hypotenuse in the right-angled triangular cross-sectional shape of the C-ring is press-fitted against the bottom surface of the ring groove of the short cylindrical body. One end of the outer cylinder is hooked to one end of the rotating cylinder.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The inventors have found that when a ceramic inner tube is inserted into a metal heating tube and a powdered material is heat-treated, the amount of the material recovered from the heating furnace may decrease. [Means for solving the problem]

[0005] The heating furnace disclosed herein comprises a heating tube made of a metal material, a furnace body that covers the heating tube and forms a heating space between itself and the heating tube, an inner tube made of a ceramic material disposed inside the heating tube and having a transport space formed inside for transporting the material to be processed, a biasing member disposed on at least one of the longitudinal sides of the inner tube and biasing the inner tube in the longitudinal direction, and a stopper that restricts the inner tube from separating from the heating tube. With this heating furnace, it is possible to suppress a decrease in the amount of powdery material recovered from the heating furnace. [Brief explanation of the drawing]

[0006] [Figure 1] Figure 1 is a schematic diagram of a heating furnace. [Figure 2] Figure 2 is a cross-sectional view taken along line II-II in Figure 1. [Figure 3] Figure 3 is a schematic cross-sectional view showing the inside of a heating tube in a reference example. [Figure 4] Figure 4 is a schematic cross-sectional view showing the inside of a heating tube during the heat treatment of an object to be processed, as shown in the reference example. [Figure 5] Figure 5 is a schematic diagram showing the inside of a heating tube according to one embodiment. [Figure 6] Figure 6 is a schematic enlarged view showing the vicinity of the front end of a heating tube according to one embodiment. [Figure 7] Figure 7 is a schematic enlarged view showing the vicinity of the rear end of a heating tube according to one embodiment. [Modes for carrying out the invention]

[0007] Hereinafter, an embodiment of the technology disclosed herein will be described with reference to the drawings. Naturally, the embodiment described herein is not intended to particularly limit the present invention. Furthermore, components and parts that perform the same function will be appropriately denoted by the same reference numerals, and redundant descriptions will be omitted as appropriate. In the drawings, the reference numerals F, Rr, L, R, U, and D represent front, back, left, right, top, and bottom, respectively. These directions are defined solely for the convenience of explanation and do not limit the present invention unless otherwise specified.

[0008] Figure 1 is a schematic diagram of the heating furnace 1. In Figure 1, the inside of the heating tube 10 is schematically shown. In Figure 1, the direction in which the material to be processed A is conveyed is indicated by a white arrow. In the configuration shown in Figure 1, the material to be processed A is conveyed from rear to front. In the heating furnace 1, the powdered material to be processed A is heat-treated. As shown in Figure 1, the heating furnace 1 comprises a heating tube 10, a furnace body 20, a drive mechanism 30, a material supply unit 40, a material recovery unit 45, and a heating device 50. The heating furnace 1 shown in Figure 1 is a so-called rotary kiln that heats the material to be processed A while rotating the heating tube 10.

[0009] The heating tube 10 is inserted into the furnace body 20. The heating tube 10 is cylindrical and extends in the front-rear direction. In the configuration shown in Figure 1, the rear end 11 and front end 12 of the heating tube 10 protrude from the furnace body 20. The rear end 11 and front end 12 of the heating tube 10 are open. The heating tube 10 is rotated by the drive mechanism 30 around a rotation axis W set along the direction in which the workpiece A is transported. The dimensions of the heating tube 10, such as the inner diameter, outer diameter, and length, can be appropriately changed according to the processing conditions of the workpiece A. The heating tube 10 may have flanges or the like, and may not be a perfect cylinder in all details.

[0010] The heating tube 10 is made of a metal material. In this embodiment, stainless steel material such as SUS310 or SUS316 is used for the heating tube 10. However, heat-resistant cast steel or the like may also be used for the heating tube 10.

[0011] In the configuration shown in Figure 1, the heating tube 10 is depicted as extending horizontally in the front-to-back direction, but in reality, a predetermined angle of gradient may be set. The heating tube 10 may be positioned so that the rear end 11 is higher than the front end 12. This allows the material to be processed A to be transported from rear to front in accordance with the rotation of the heating tube 10. From this perspective, the heating tube 10 may be installed with a gradient of, for example, an angle of 0.5 to 1 degree. With a gradient of 0.5 to 1 degree, the powdery material to be processed A is less likely to slide off, and the powdery material to be processed A is easily transported at an appropriate speed in accordance with the rotation of the heating tube 10. Therefore, by adjusting the rotation speed of the heating tube 10, the time that the material to be processed A remains inside the heating tube 10 can be adjusted. The angle of the gradient is not limited to the above, and an appropriate angle, for example, an angle of 0.3 to 5 degrees, may be selected.

[0012] The furnace body 20 surrounds the heating tube 10. In the configuration shown in Figure 1, the length of the furnace body 20 in the front-to-back direction is shorter than the length of the heating tube 10 in the longitudinal direction. A heating space 20a is formed between the furnace body 20 and the heating tube 10. That is, heating spaces 20a are formed above, below, and to the left and right of the heating tube 10. The furnace body 20 is made of a material that has heat resistance and heat insulation properties. The furnace body 20 may be made of materials such as refractory bricks, refractory blocks, castable refractories, or ceramic fiberboards.

[0013] Figure 2 is a cross-sectional view taken along line II-II of Figure 1. As shown in Figures 1 and 2, the furnace body 20 has a bottom wall 21, a pair of side walls 22, a top wall 23, a rear wall 24, and a front wall 25. The thickness of each wall of the furnace body 20 is set to a thickness sufficient to adequately insulate the heat inside the heating space 20a. Partitions 27 may be provided inside the furnace body 20 to divide the heating space 20a into multiple spaces along the front-to-back direction. Although not shown, the perimeter of the furnace body 20 may be covered with a metal (e.g., stainless steel) outer wall.

[0014] The bottom wall 21 and side walls 22 are approximately rectangular parallelepipeds in shape. As shown in Figure 2, the length of the bottom wall 21 in the left-right direction is greater than the outer diameter of the heating tube 10. A pair of side walls 22 extend upward from the left and right ends of the bottom wall 21. The upper ends of the side walls 22 reach approximately the center of the heating tube 10. A top wall 23 rests on the upper ends of the pair of side walls 22. The top wall 23 is semicircular (arch-shaped). Both left and right ends of the top wall 23 are supported by the pair of side walls 22. The shape of the top wall 23 is not particularly limited and may be formed horizontally (parallel to the bottom wall 21).

[0015] As shown in Figure 1, the rear wall 24 extends upward from the rear end of the bottom wall 21. The front wall 25 extends upward from the front end of the bottom wall 21. A through hole 24a is formed in the rear wall 24. A through hole 25a is formed in the front wall 25. The through holes 24a and 25a are approximately circular in shape. The heating tube 10 is inserted through the through holes 24a and 25a.

[0016] The drive mechanism 30 rotates the heating tube 10. As shown in Figure 1, the drive mechanism 30 is located outside the furnace body 20. In this embodiment, the drive mechanism 30 rotates only the heating tube 10 of the furnace body 20 and the heating tube 10. The drive mechanism 30 rotates the heating tube 10 about the axis of rotation W.

[0017] The drive mechanism 30 comprises a sprocket 31, a pair of tires 32 and 33, and a pair of rollers 34 and 35. The sprocket 31 is positioned behind the furnace body 20. The sprocket 31 is mounted along the outer surface of the heating tube 10. Although not shown, a chain is wound around the sprocket 31. The chain is driven by a drive device (not shown). The driving force of the drive device is transmitted to the heating tube 10 via the chain and the sprocket 31.

[0018] The tire 32 is arranged behind the sprocket 31. The tire 33 is arranged in front of the furnace body 20. The pair of tires 32 and 33 are formed in an annular shape. The pair of tires 32 and 33 are attached along the outer peripheral surface of the heating pipe 10. The tire 32 is rotatably supported by the roller 34. The tire 33 is rotatably supported by the roller 35. The heating pipe 10 rotates on the rollers 34 and 35 via the tires 32 and 33.

[0019] The material supply unit 40 is connected to the rear end 11 of the heating pipe 10. The material supply unit 40 supplies the workpiece A into the heating pipe 10. In the form shown in FIG. 1, the material supply unit 40 has a hopper 41 and a screw feeder 42. The hopper 41 contains the workpiece A before processing. The screw feeder 42 is connected to the hopper 41. The discharge port 42a of the screw feeder 42 is inserted into the heating pipe 10. The screw feeder 42 supplies the workpiece A contained in the hopper 41 into the heating pipe 10. In the form shown in FIG. 1, the rear end 11 of the heating pipe 10 is covered by a duct 43 for dust collection. However, the rear end 11 of the heating pipe 10 may not be covered by the duct 43.

[0020] The material recovery unit 45 is connected to the front end 12 of the heating pipe 10. In the material recovery unit 45, the workpiece A discharged from the inside of the heating pipe 10 is recovered. In the form shown in FIG. 1, the material recovery unit 45 is a rectangular container that covers the front end 12 of the heating pipe 10. An opening 45a is provided at the lower part of the material recovery unit 45. The workpiece A discharged from the inside of the heating pipe 10 into the material recovery unit 45 is appropriately discharged from the opening 45a of the material recovery unit 45 and recovered.

[0021] The heating device 50 heats the heating space 20a. In the form shown in FIG. 1, the heating furnace 1 includes 16 heating devices 50. The heating devices 50 are arranged inside the heating space 20a. In the form shown in FIG. 1, 8 heating devices 50 are arranged below the heating tube 10, and the remaining 8 heating devices 50 are arranged above the heating tube 10. Note that the type of the heating device 50 is not particularly limited and can be appropriately selected according to the heating conditions of the workpiece A, etc. The heating device 50 may be, for example, a burner or an electric heater. When a burner is used as the heating device 50, the heating furnace 1 may include a fuel supply pipe for supplying fuel gas to the heating space 20a and an air supply pipe for supplying air to the heating space 20a. Also, the arrangement of the heating device 50 is not particularly limited. For example, the heating device 50 may be arranged on the side of the heating tube 10. The number and output of the heating device 50, etc. can be appropriately set according to the processing conditions of the workpiece A. By changing the number and output of the heating device 50, etc., the workpiece A can be processed under various processing conditions.

[0022] Although not shown in the figure, the furnace body 20 may be provided with a temperature sensor for measuring the temperature of the heating space 20a. As this temperature sensor, for example, a thermocouple, etc. can be used. Thereby, since the heating device 50 can be controlled according to the temperature of the heating space 20a, the heating space 20a can be heated to a desired temperature.

[0023] By the way, when the workpiece A is supplied into the heating tube 10 and the workpiece A is heat-treated in a state where the heating tube 10 and the workpiece A are in contact, there is a possibility that impurities such as metal ions and metal oxides derived from the metal material used for the heating tube 10 may be mixed into the workpiece A. For example, when the workpiece A after the heat treatment is used as the active material of a battery, it is not preferable for such impurities to be mixed into the workpiece A. Depending on the type and use of the workpiece A, etc., there may be a case where it is desired to perform the heat treatment of the workpiece A without bringing the heating tube 10 and the workpiece A into contact.

[0024] Figure 3 is a schematic cross-sectional view showing the inside of a heating tube 10 according to a reference example. As shown in Figure 3, the heating furnace 1 is equipped with an inner tube 15. In Figure 3, the inside of the inner tube 15 is shown in a cross-sectional view. The inner tube 15 is made of a ceramic material. For example, alumina is used for the inner tube 15. However, materials other than alumina may be used for the inner tube 15. For example, the inner tube 15 may be made of zirconia or silicon carbide. The inner tube 15 is inserted into the heating tube 10 and is positioned inside the heating tube 10. The inner tube 15 is formed in a cylindrical shape and extends in the front-to-back direction. In the configuration shown in Figure 3, at room temperature, the longitudinal length of the inner tube 15 is equal to the longitudinal length of the heating tube 10. Here, "equal" includes cases where they are exactly equal and cases where they are approximately equal. The outer diameter of the inner tube 15 is about 2 mm to 5 mm smaller than the inner diameter of the heating tube 10.

[0025] A transport space 15a is formed inside the inner tube 15, through which the material to be processed A is transported. A supply port 16a is formed at the rear end 16 of the inner tube 15. The discharge port 42a of the screw feeder 42 is inserted into the inner tube 15 from the supply port 16a. A discharge port 17a is formed at the front end 17 of the inner tube 15. The discharge port 17a is covered by the material recovery section 45. As a result, the material to be processed A is heated in the transport space 15a formed inside the inner tube 15. Therefore, the material to be processed A can be heated without the heating tube 10 coming into contact with the material to be processed A.

[0026] However, according to the inventors' findings, when a workpiece A is heat-treated by inserting a ceramic inner tube 15 into a metal heating tube 10, as shown in the configuration in Figure 3, the amount of workpiece A recovered in the material recovery section 45 may decrease. The inventors believe the reason for this is as follows.

[0027] Figure 4 is a schematic cross-sectional view showing the inside of the heating tube 10 when the workpiece A is being heat-treated, according to a reference example. When the workpiece A is being heat-treated, the heating tube 10 and the inner tube 15 are heated together with the workpiece A by the heating device 50. As a result, the heating tube 10 and the inner tube 15 expand due to heat. However, since the heating tube 10 and the inner tube 15 are made of different materials, their coefficients of thermal expansion are different. Therefore, there may be a difference between the amount of thermal expansion of the heating tube 10 and the amount of thermal expansion of the inner tube 15. Specifically, in this embodiment, the heating tube 10 is made of a metal material, and the inner tube 15 is made of a ceramic material. Since the coefficient of thermal expansion of the ceramic material is smaller than that of the metal material, the amount of thermal expansion of the inner tube 15 may be smaller than that of the heating tube 10. Therefore, as shown in Figure 4, a gap 18 may occur between the rear end 11 of the heating tube 10 and the rear end 16 of the inner tube 15. The material to be processed A may become trapped in the gap 18, making it impossible to discharge the material to be processed A from inside the heating tube 10.

[0028] Figure 5 is a schematic diagram showing the inside of the heating tube 10 according to this embodiment. Figure 6 is a schematic enlarged view showing the vicinity of the front end 12 of the heating tube 10 according to this embodiment. Figure 7 is a schematic enlarged view showing the vicinity of the rear end 11 of the heating tube 10 according to this embodiment. In the configuration shown in Figure 5, at room temperature, the longitudinal length of the inner tube 15 is shorter than the longitudinal length of the heating tube 10. The longitudinal length of the inner tube 15 may be, for example, about 50 mm to 100 mm shorter than the longitudinal length of the heating tube 10. As shown in Figures 5 to 7, the heating furnace 1 includes a sleeve 60, a biasing member 65, and stoppers 68 and 69.

[0029] As shown in Figure 5, the sleeve 60 is positioned on the longitudinal outer side of the inner pipe 15. In the configuration shown in Figure 5, the sleeve 60 is positioned on the discharge side of the material to be processed A, on one of the longitudinal sides of the inner pipe 15. That is, in the configuration shown in Figure 5, the sleeve 60 is positioned on the front side of the inner pipe 15. The sleeve 60 is in contact with the front end 17 of the inner pipe 15. The sleeve 60 may be formed from a single component with the inner pipe 15, or from separate components. If the inner pipe 15 and the sleeve 60 are formed from separate components, the sleeve 60 may or may not be joined to the inner pipe 15. The sleeve 60 may be made of a ceramic material, or from a metallic material.

[0030] As shown in Figure 6, the sleeve 60 has a cylindrical portion 62 and a flange portion 64 provided at one end of the cylindrical portion 62. The cylindrical portion 62 is formed in a cylindrical shape and extends in the front-rear direction. The cylindrical portion 62 extends from the inside of the heating tube 10 to the outside of the heating tube 10. The other end of the cylindrical portion 62 is positioned further outward in the longitudinal direction of the heating tube 10 than the stopper 68. In the configuration shown in Figure 5, the front end of the cylindrical portion 62 is located in front of the stopper 68. In this embodiment, the inner diameter of the cylindrical portion 62 is equal to the inner diameter of the inner tube 15.

[0031] In the configuration shown in Figure 6, the flange portion 64 is provided at the rear end of the cylindrical portion 62. The flange portion 64 protrudes radially outward from the cylindrical portion 62 toward the heating tube 10. The flange portion 64 is in contact with the front end 17 of the inner tube 15.

[0032] The biasing member 65 biases the inner tube 15 in the longitudinal direction of the inner tube 15. In the configuration shown in Figure 5, the biasing member 65 biases the inner tube 15 toward the rear. In the configuration shown in Figure 5, the biasing member 65 is a compression coil spring.

[0033] The biasing member 65 is located on at least one of the longitudinal sides of the inner tube 15. In the configuration shown in Figure 5, the biasing member 65 is located on the discharge side of the material to be processed A on the longitudinal side of the inner tube 15. That is, in the configuration shown in Figure 5, the biasing member 65 is located in front of the inner tube 15. The biasing member 65 is located inside the heating tube 10. The biasing member 65 is located around the cylindrical portion 62. In the configuration shown in Figure 6, the biasing member 65 is located so as to be wrapped around the cylindrical portion 62. In the front-rear direction, the biasing member 65 is located between the flange portion 64 and the restricting portion 68b of the stopper 68.

[0034] The stoppers 68 and 69 are components that restrict the inner tube 15 from separating from the heating tube 10. In the configuration shown in Figure 5, the stoppers 68 and 69 are arranged on both sides in the longitudinal direction of the heating tube 10. In the configuration shown in Figure 5, two stoppers 68 are arranged on the front side of the heating tube 10, and two stoppers 69 are arranged on the rear side of the heating tube 10. In the configuration shown in Figure 5, the stoppers 68 and 69 are formed in an L-shape.

[0035] As shown in Figure 6, the stopper 68 has a base 68a and a restricting portion 68b. The base 68a extends in the front-rear direction. The rear end of the base 68a is fixed to the tire 33. The base 68a may be fixed to the tire 33, for example, using screws. The front end of the base 68a is positioned in front of the front end 12 of the heating tube 10. One end of the restricting portion 68b is connected to the front end of the base 68a. The restricting portion 68b extends along the radial direction of the heating tube 10. The other end of the restricting portion 68b is positioned radially inward of the heating tube 10 beyond the inner circumferential surface 14 of the heating tube 10. When viewed from the front, the other end of the restricting portion 68b overlaps with the biasing member 65 and the flange portion 64 of the sleeve 60. The biasing member 65 is in contact with the stopper 68.

[0036] As shown in Figure 7, the stopper 69 has a base 69a and a restricting portion 69b. The base 69a extends in the front-rear direction. The front end of the base 69a is fixed to the tire 32. The base 69a may be fixed to the tire 32, for example, using screws. The rear end of the base 69a is located behind the rear end 11 of the heating tube 10. One end of the restricting portion 69b is connected to the rear end of the base 69a. The restricting portion 69b extends along the radial direction of the heating tube 10. The other end of the restricting portion 69b is located radially inward of the heating tube 10, relative to the inner circumferential surface 14 of the heating tube 10. When viewed from the rear, the other end of the restricting portion 69b overlaps with a portion of the inner tube 15. The rear end 16 of the inner tube 15 contacts the restricting portion 69b.

[0037] As described above, the heating furnace 1 according to this embodiment includes a biasing member 65 and stoppers 68 and 69. The biasing member 65 is positioned in front of the inner tube 15 and biases the inner tube 15 toward the rear. The stoppers 68 and 69 restrict the inner tube 15 from separating from the heating tube 10.

[0038] In the heating furnace 1 of this embodiment, the inner tube 15 is biased backward by the biasing member 65. As a result, even when there is a difference between the amount of thermal expansion of the heating tube 10 and the amount of thermal expansion of the inner tube 15, the rear end 16 of the inner tube 15 is pressed against the stopper 69. Therefore, no gap is created between the rear end 11 of the heating tube 10 and the rear end 16 of the inner tube 15. Consequently, the heating furnace 1 of this embodiment can prevent the material to be processed A from entering the gap between the heating tube 10 and the inner tube 15. This can suppress a decrease in the amount of material to be processed A recovered in the material recovery section 45.

[0039] According to this embodiment, the heating furnace 1 includes a sleeve 60 positioned on the longitudinal outside of the inner tube 15. The sleeve 60 has a cylindrical portion 62 and a flange portion 64. The cylindrical portion 62 extends from the inside of the heating tube 10 to the outside of the heating tube 10. The flange portion 64 is provided at the rear end of the cylindrical portion 62 and contacts the front end 17 of the inner tube 15. The biasing member 65 is positioned around the cylindrical portion 62 and between the flange portion 64 and the stopper 68. As a result, the workpiece A moves from rear to front through the sleeve 60. The biasing member 65 is positioned outside the sleeve 60. Therefore, the biasing member 65 does not come into contact with the workpiece A. Wear of the biasing member 65 can be suppressed.

[0040] According to this embodiment, the sleeve 60 and the biasing member 65 are positioned on the side of the inner tube 15 where the workpiece A is discharged. As a result, when the workpiece A is discharged from inside the heating tube 10, it passes through the sleeve 60. Therefore, the workpiece A is discharged from inside the heating tube 10 without hitting the stopper 68. This makes it easier to discharge the workpiece A from inside the heating tube 10. In addition, wear on the stopper 68 can be suppressed.

[0041] According to this embodiment, the biasing member 65 is a compression coil spring. This allows the inner tube 15 to be biased towards the stopper 69 with a simple configuration.

[0042] The above describes one embodiment of the proposed technology. However, the above-described embodiment is merely an example, and the technology can be implemented in other ways.

[0043] In the above embodiment, the stopper 68 was fixed to the tire 33 of the drive mechanism 30, and the stopper 69 was fixed to the tire 32. However, the method of fixing the stoppers 68 and 69 is not limited to this. The stoppers 68 and 69 may be fixed to the furnace body 20, for example, or to the heating tube 10. In this way, if the stoppers 68 and 69 are fixed to a part other than the drive mechanism 30, the heating furnace 1 does not need to be equipped with the drive mechanism 30.

[0044] In the above embodiment, the material supply unit 40 had a hopper 41 and a screw feeder 42. However, the material supply unit 40 is not limited to the configuration of the above embodiment. The material supply unit 40 may have, for example, a chute or a vibrating feeder instead of the screw feeder 42.

[0045] In the above embodiment, the biasing member 65 was positioned in front of the inner pipe 15. However, the biasing member 65 may be positioned behind the inner pipe 15. The biasing member 65 may be positioned both in front of and behind the inner pipe 15. Also, in the above embodiment, the sleeve 60 was positioned in front of the inner pipe 15. However, if the biasing member 65 is positioned behind the inner pipe 15, the sleeve 60 may be positioned behind the inner pipe 15. If the biasing member 65 is positioned both in front of and behind the inner pipe 15, the sleeve 60 may be positioned both in front of and behind the inner pipe 15.

[0046] In the above embodiment, the biasing member 65 was a compression coil spring. However, the type of biasing member 65 is not limited to this. The biasing member 65 may be a member made of rubber material. In this case, the biasing member 65 biases the inner tube 15 by the elastic force of the rubber.

[0047] The technologies disclosed herein have been described in detail above. Unless otherwise specified, the embodiments and other details mentioned herein do not limit the present invention. Furthermore, the technologies disclosed herein can be modified in various ways, and each component and each process mentioned herein may be omitted or combined as appropriate, unless no particular problems arise. This specification also includes the disclosures described in the following sections.

[0048] Section 1: A heating tube made of metal material, A furnace body that covers the periphery of the heating tube and forms a heating space between itself and the heating tube, An inner tube made of ceramic material is placed inside the heating tube, and a transport space is formed inside through which the object to be processed is transported. A biasing member is provided on at least one of the longitudinal sides of the inner tube, which biases the inner tube in the longitudinal direction. A stopper that restricts the inner tube from separating from the heating tube, A heating furnace equipped with the following features.

[0049] Section 2: The inner tube is provided with a sleeve positioned on the longitudinally outer side, The aforementioned sleeve is A cylindrical portion extending from the inside of the heating tube to the outside of the heating tube, A flange portion is provided at one end of the cylindrical portion and contacts the end of the inner pipe. It has, The heating furnace according to item 1, wherein the biasing member is arranged around the cylindrical portion and between the flange portion and the stopper.

[0050] Section 3: The heating furnace according to claim 1 or 2, wherein the sleeve and the biasing member are arranged on the side of the inner tube in the longitudinal direction that discharges the material to be processed.

[0051] Section 4: The heating furnace according to any one of claims 1 to 3, wherein the biasing member is a compression coil spring.

[0052] Section 5: A heating furnace according to any one of claims 1 to 4, comprising a drive mechanism for rotating the heating tube. [Explanation of Symbols]

[0053] 1 Furnace 10 heating tube 15 Inner pipe 15a Conveying space 20 Furnace body 20a heating space 30 Drive mechanism 60 sleeves 62 Cylindrical part 64 Flange section 65. Biasing member 68, 69 Stopper A. Workpiece to be processed

Claims

1. A heating tube made of metal material, A furnace body that covers the periphery of the heating tube and forms a heating space between itself and the heating tube, An inner tube made of ceramic material is placed inside the heating tube, and a transport space is formed inside through which the object to be processed is transported. A biasing member is provided on at least one of both sides in the longitudinal direction of the inner tube, and biases the inner tube in the longitudinal direction. A stopper that restricts the inner tube from separating from the heating tube, A heating furnace equipped with the following features.

2. The inner tube is provided with a sleeve positioned on the longitudinally outer side, The aforementioned sleeve is A cylindrical portion extending from the inside of the heating tube to the outside of the heating tube, A flange portion is provided at one end of the cylindrical portion and contacts the end of the inner pipe. It has, The heating furnace according to claim 1, wherein the biasing member is arranged around the cylindrical portion and between the flange portion and the stopper.

3. The heating furnace according to claim 2, wherein the sleeve and the biasing member are arranged on the side of the inner tube in the longitudinal direction that discharges the workpiece.

4. The heating furnace according to claim 1, wherein the biasing member is a compression coil spring.

5. The heating furnace according to claim 1, further comprising a drive mechanism for rotating the heating tube.

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