Heating furnace

Abstract

To provide a technique which can suppress variations in an amount of heat applied to objects to be treated within a temperature maintenance space.SOLUTION: A heating furnace heats each object to be treated. The heating furnace comprises: a carry-in port; a carry-out port; a furnace body which has a furnace inner space extending in a conveyance direction from the carry-in port to the carry-out port; and a conveyance apparatus in which the object to be treated can be mounted on a conveyance face, and which conveys the object to be treated in the conveyance direction. The furnace inner space comprises: a preheating space which is communicated with the carry-in port, and in which the object to be treated is preheated; a temperature maintenance space which is communicated with the preheating space, and in which the object to be treated is heated and a temperature thereof is fixedly maintained; and a cooling space which is communicated with the temperature maintenance space and the carry-out port, and in which the object to be treated is cooled. When the furnace body is cut along a face orthogonal to the conveyance direction, a cross sectional area of the temperature maintenance space is larger than a cross sectional area of the preheating space.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The technology disclosed in this specification relates to a heating furnace. [Background technology]

[0002] Patent Document 1 discloses a heating furnace. The furnace body of the heating furnace has an inlet, an outlet, and an internal space extending in the conveying direction from the inlet to the outlet. The internal space includes a preheating space communicating with the inlet, a temperature maintenance space communicating with the preheating space, and a cooling space communicating with the temperature maintenance space and the outlet. When the furnace body is cut along a plane perpendicular to the conveying direction, the cross-sectional area of ​​the temperature maintenance space is smaller than the cross-sectional area of ​​the preheating space. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2023-507663 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned heating furnace, the volume of the atmospheric gas in the temperature maintenance space is small, so that the atmosphere in the temperature maintenance space is easily subject to large fluctuations due to external disturbances, which makes it easy for the temperature in the temperature maintenance space to vary, resulting in variation in the amount of heat applied to the workpiece in the temperature maintenance space.

[0005] This specification discloses a technique that can suppress variations in the amount of heat applied to an object to be treated in a temperature-maintaining space. [Means for solving the problem]

[0006] In a first aspect of the technology disclosed herein, a heating furnace heats a workpiece. The heating furnace includes a furnace body having an inlet, an outlet, and an internal space extending in a transport direction from the inlet to the outlet, and a transport device on which the workpiece can be placed and which transports the workpiece in the transport direction. The internal space includes a preheating space communicating with the inlet and preheating the workpiece, a temperature maintenance space communicating with the preheating space and heating the workpiece, the temperature of the temperature maintenance space being maintained constant, and a cooling space communicating with the temperature maintenance space and the outlet and cooling the workpiece. When the furnace body is cut along a plane perpendicular to the transport direction, the cross-sectional area of ​​the temperature maintenance space is larger than the cross-sectional area of ​​the preheating space.

[0007] With the above configuration, when the furnace body is cut along a plane perpendicular to the conveying direction, the atmosphere in the temperature maintaining space is less likely to fluctuate due to disturbances, and temperature variations in the temperature maintaining space are less likely to occur, compared to a configuration in which the cross-sectional area of ​​the temperature maintaining space is smaller than the cross-sectional area of ​​the preheating space, thereby making it possible to suppress variations in the amount of heat applied to the workpieces in the temperature maintaining space. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram of a heating furnace according to a first embodiment. [Figure 2] FIG. 2 is a schematic diagram of a preheating space of the heating furnace of the first embodiment and its vicinity. [Figure 3] 1 is a schematic diagram of a heating furnace according to a first embodiment cut along a plane perpendicular to the conveying direction. [Figure 4] FIG. 2 is a schematic diagram of the cooling space of the heating furnace of the first embodiment and its vicinity. [Figure 5] FIG. 10 is a schematic diagram of a heating furnace according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] The main features of the embodiments described below are listed below. Note that the technical elements described below are independent technical elements that exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing.

[0010] In a second aspect of the technology disclosed in this specification, when the furnace body in the first aspect is cut along a plane perpendicular to the transport direction, the cross-sectional area of ​​the temperature maintaining space is larger than the cross-sectional area of ​​the cooling space. This configuration makes it possible to prevent atmospheric gas in the temperature maintaining space from flowing into the cooling space, thereby making it easier to adjust the temperature of the cooling space.

[0011] In a third aspect of the technology disclosed in the present specification, when the furnace body in the second aspect is cut along a plane perpendicular to the conveying direction, the cross-sectional area of ​​the cooling space is smaller than the cross-sectional area of ​​the preheating space. With the above configuration, it is possible to more easily adjust the temperature of the cooling space.

[0012] In a fourth aspect of the technology disclosed in this specification, when the furnace body is cut along a plane perpendicular to the transport direction in the second or third aspect, the height of the temperature maintaining space is 1.1 times or more the height of the cooling space. This configuration can further prevent atmospheric gas in the temperature maintaining space from flowing into the cooling space, making it easier to adjust the temperature of the cooling space.

[0013] In a fifth aspect of the technology disclosed in this specification, in the fourth aspect, the height of the cooling space gradually decreases toward the outlet. This configuration can prevent the ambient gas in the temperature maintenance space from flowing deep into the cooling space. This makes it easier to adjust the temperature of the cooling space.

[0014] In a sixth aspect of the technology disclosed in this specification, in the fifth aspect, the cooling space includes a first cooling space having a first height, and a second cooling space communicating with the first cooling space, disposed in the transport direction relative to the first cooling space, and having a second height. The second height is 0.9 times or less of the first height. The length of the first cooling space in the transport direction and the length of the second cooling space in the transport direction are each equal to or greater than the length of the workpiece in the transport direction. This configuration can prevent ambient gas in the temperature maintenance space from flowing to the second cooling space. This makes it easier to adjust the temperature of the cooling space.

[0015] In a seventh aspect of the technology disclosed in this specification, in any one of the fourth to sixth aspects, when the furnace body is cut along a plane perpendicular to the conveying direction, the furnace width of the temperature maintaining space is larger than the furnace width of the cooling space. This configuration makes it easier to adjust the temperature of the cooling space.

[0016] In an eighth aspect of the technology disclosed herein, in any one of the first to seventh aspects, the preheating space includes a first preheating space. When the furnace body is cut along a plane perpendicular to the transport direction, the height of the temperature maintaining space is 1.1 times or more the height of the first preheating space. This configuration makes it more difficult for temperature variations to occur in the temperature maintaining space. This makes it possible to further suppress variations in the amount of heat applied to the workpiece in the temperature maintaining space.

[0017] In a ninth aspect of the technology disclosed in this specification, in the heating furnace of the eighth aspect described above, the preheating space further includes a second preheating space communicating with the first preheating space and the temperature maintaining space. The height of the second preheating space gradually increases toward the temperature maintaining space. The length of the second preheating space in the transport direction is equal to or greater than the length of the workpiece in the transport direction. With the above configuration, ambient gas in the temperature maintaining space easily flows through the second preheating space to the first preheating space. This allows the heat from the temperature maintaining space to increase the temperature of the first preheating space and the second preheating space.

[0018] In a tenth aspect of the technology disclosed herein, in the eighth or ninth aspect described above, when the furnace body is cut along a plane perpendicular to the transport direction, the furnace width of the temperature maintaining space is greater than the furnace width of the preheating space. This configuration makes it more difficult for temperature variations to occur in the temperature maintaining space. This further reduces variations in the amount of heat applied to the workpiece in the temperature maintaining space.

[0019] In an eleventh aspect of the technology disclosed in this specification, in any one of the first to tenth aspects, the cross-sectional area of ​​the temperature maintaining space is constant in the transport direction. With this configuration, temperature variations in the temperature maintaining space are less likely to occur. This makes it possible to further suppress variations in the amount of heat applied to the workpiece in the temperature maintaining space.

[0020] (First Example) The heating furnace 10 of the first embodiment shown in FIG. 1 heats a workpiece 2. The workpiece 2 includes a sagger 4. The sagger 4 has a roughly rectangular box shape. The sagger 4 accommodates the workpiece body inside. The workpiece body is, for example, a powder of raw material for ceramic capacitors, a positive electrode material or a negative electrode material for lithium-ion batteries, or the like.

[0021] The heating furnace 10 includes a furnace body 12 and a conveying device 14 .

[0022] The furnace body 12 is an elongated, heat-insulating structure. The interior of the furnace body 12 is filled with atmospheric gas. The atmospheric gas is, for example, nitrogen gas. The furnace body 12 has an inlet 18, an outlet 20, and an internal furnace space 22. The inlet 18 is located at one longitudinal end of the furnace body 12. The outlet 20 is located at the other longitudinal end of the furnace body 12. The internal furnace space 22 is connected to a first space 23 via the inlet 18 and to a second space 24 via the outlet 20. The first space 23 and the second space 24 are connected to spaces outside the furnace body 12. In a modified example, the first space 23 and the second space 24 may not be formed. In this configuration, the internal furnace space 22 may be connected to spaces outside the furnace body 12 via the inlet 18 and the outlet 20, respectively.

[0023] The conveying device 14 is, for example, a roller-type conveying device. In a modified example, the conveying device 14 may be a pusher-type conveying device equipped with a pusher that pushes a conveying plate or a carriage equipped with wheels. The conveying device 14 includes a plurality of rollers 26 aligned in the longitudinal direction of the furnace body 12. Both ends of the rollers 26 are rotatably supported. The rollers 26 are rotated by a driving device (not shown). The workpiece 2 can be placed on a conveying surface 28 of the conveying device 14. Note that a single workpiece 2 may be placed on the conveying surface 28, or multiple workpieces 2 may be placed on the conveying surface 28 in a vertically stacked state. The conveying surface 28 is a surface that includes the upper ends of the rollers 26 and is aligned along the conveying direction D1. The conveying device 14 conveys the workpiece 2 in the conveying direction D1 by rotating the rollers 26 with the workpiece 2 placed on the conveying surface 28. As a result, the workpiece 2 is carried from the first space 23 into the furnace space 22 through the carry-in port 18, passes through the furnace space 22, and then is carried out into the second space 24 through the carry-out port 20. The transport direction D1 is approximately the same as the longitudinal direction of the furnace body 12.

[0024] The furnace space 22 includes a preheating space 32, a temperature maintaining space 34, and a cooling space 36. The preheating space 32, the temperature maintaining space 34, and the cooling space 36 are arranged in this order in the conveying direction D1.

[0025] The preheating space 32 is in communication with the carry-in entrance 18. A plurality of heaters (not shown) are arranged in the preheating space 32. The temperature of the preheating space 32 increases from the carry-in entrance 18 toward the carry-out exit 20 (i.e., toward the conveying direction D1). The preheating space 32 preheats the workpiece 2 (i.e., the workpiece body) as the workpiece 2 passes through the preheating space 32. When the workpiece body is preheated, gas is generated from the workpiece body.

[0026] The furnace body 12 has a first exhaust port 40, and the preheating space 32 is in communication with the first exhaust port 40. The first exhaust port 40 is located, for example, near the carry-in entrance 18. The first exhaust port 40 penetrates the ceiling wall 12a of the furnace body 12. The preheating space 32 is provided with a plurality of air supply pipes (not shown) for supplying atmospheric gas. After being supplied to the preheating space 32 from the plurality of air supply pipes, the atmospheric gas flows through the preheating space 32 in the direction opposite to the transfer direction D1 and is discharged from the first exhaust port 40 to the space outside the furnace body 12. The atmospheric gas is also discharged to the space outside the furnace body 12 together with gas generated from the workpiece body.

[0027] The temperature maintaining space 34 is in communication with the preheating space 32. A plurality of heaters (not shown) are arranged in the temperature maintaining space 34. The temperature of the temperature maintaining space 34 is maintained substantially constant. The temperature of the temperature maintaining space 34 is higher than the temperature of the preheating space 32. The temperature maintaining space 34 heats (i.e., bakes) the workpiece 2 as it passes through the temperature maintaining space 34.

[0028] A plurality of air supply pipes (not shown) that supply atmospheric gas are arranged in the temperature maintaining space 34. After being supplied to the temperature maintaining space 34 from the plurality of air supply pipes, the atmospheric gas flows through the temperature maintaining space 34 in the direction opposite to the conveying direction D1 and is discharged into the preheating space 32. This allows the heat from the temperature maintaining space 34 to raise the temperature of the preheating space 32.

[0029] The cooling space 36 is in communication with both the temperature maintaining space 34 and the discharge port 20. A plurality of cooling pipes (not shown) through which a refrigerant can pass are arranged in the cooling space 36. The temperature of the cooling space 36 decreases toward the discharge port 20 (i.e., toward the conveying direction D1). The temperature of the cooling space 36 is lower than the temperature of the temperature maintaining space 34. The cooling space 36 cools the workpiece 2 as the workpiece 2 passes through the cooling space 36.

[0030] The furnace body 12 has a second exhaust port 42, and the cooling space 36 is in communication with the second exhaust port 42. The second exhaust port 42 is arranged, for example, near the discharge port 20. The second exhaust port 42 penetrates the ceiling wall 12a of the furnace body 12. A plurality of air supply pipes (not shown) that supply atmospheric gas are arranged in the cooling space 36. The atmospheric gas is supplied to the cooling space 36 from the plurality of air supply pipes, then flows through the cooling space 36 in the transfer direction D1 and is discharged from the second exhaust port 42 to a space outside the furnace body 12.

[0031] 2, the preheating space 32 includes a first preheating space 50 and a second preheating space 52. The first preheating space 50 and the second preheating space 52 are arranged in this order in the conveying direction D1. The first preheating space 50 communicates with both the carry-in entrance 18 and the first exhaust port 40. The second preheating space 52 communicates with both the first preheating space 50 and the temperature maintaining space 34.

[0032] The length L1 of the first preheating space 50 in the conveying direction D1 is longer than the length L0 of the workpiece 2 in the conveying direction D1. The height H1 of the first preheating space 50 (i.e., the distance between the ceiling wall 12a and the floor wall 12b of the furnace body 12 in the vertical direction) is approximately constant in the conveying direction D1. Furthermore, the height H11 from the conveying surface 28 to the ceiling wall 12a in the first preheating space 50 is approximately constant in the conveying direction D1. Furthermore, the height H12 from the conveying surface 28 to the floor wall 12b in the first preheating space 50 is approximately constant in the conveying direction D1. As shown in FIG. 3, when the furnace body 12 is cut along a plane perpendicular to the conveying direction D1, the furnace width W1 of the first preheating space 50 is approximately constant in the conveying direction D1. Note that in FIG. 3, the first preheating space 50 is illustrated by a dashed line. The cross-sectional area of ​​the first preheating space 50 is approximately constant in the conveying direction D1.

[0033] As shown in FIG. 2 , the length L2 of the second preheating space 52 in the conveying direction D1 is longer than the length L0 of the workpiece 2 and shorter than the length L1 of the first preheating space 50. When the furnace body 12 is cut along a plane perpendicular to the conveying direction D1, the height H2 of the second preheating space 52 (i.e., the distance between the ceiling wall 12a and the floor wall 12b of the furnace body 12 in the vertical direction) is equal to or greater than the height H1 of the first preheating space 50. The height H2 of the second preheating space 52 gradually increases from the first preheating space 50 toward the temperature maintaining space 34. When the furnace body 12 is cut along a plane perpendicular to the conveying direction D1, the height H21 from the conveying surface 28 to the ceiling wall 12a in the second preheating space 52 is equal to or greater than the height H11 of the first preheating space 50. The height H21 of the second preheating space 52 gradually increases from the first preheating space 50 toward the temperature maintaining space 34. When the furnace body 12 is cut along a plane perpendicular to the conveying direction D1, the height H22 from the conveying surface 28 to the floor wall 12b in the second preheating space 52 is approximately the same as the height H12 of the first preheating space 50. The height H22 of the second preheating space 52 is approximately constant in the conveying direction D1. As shown in FIG. 3, when the furnace body 12 is cut along a plane perpendicular to the conveying direction D1, the furnace interior width W2 of the second preheating space 52 is approximately the same as the furnace interior width W1 of the first preheating space 50. The furnace interior width W2 of the second preheating space 52 is approximately constant in the conveying direction D1. When the furnace body 12 is cut along a plane perpendicular to the conveying direction D1, the cross-sectional area of ​​the second preheating space 52 is equal to or greater than the cross-sectional area of ​​the first preheating space 50. The cross-sectional area of ​​the second preheating space 52 increases toward the conveying direction D1.

[0034] As shown in FIG. 2, the length L3 of the temperature maintaining space 34 in the conveying direction D1 is longer than the length L0 of the workpiece 2. The length L3 of the temperature maintaining space 34 is also longer than the length L2 of the second preheating space 52. The height H3 of the temperature maintaining space 34 (i.e., the distance between the ceiling wall 12a and the floor wall 12b of the furnace body 12 in the vertical direction) is approximately constant in the conveying direction D1. When the furnace body 12 is cut along a plane perpendicular to the conveying direction D1, the height H3 of the temperature maintaining space 34 is higher than the height H1 of the first preheating space 50 and is approximately the same as the height H2 of the second preheating space 52 at the boundary between the second preheating space 52 and the temperature maintaining space 34. The height H3 of the temperature maintaining space 34 is 1.1 times or more the height H1 of the first preheating space 50. The height H31 from the conveying surface 28 to the ceiling wall 12a in the temperature maintaining space 34 is approximately constant in the conveying direction D1. When the furnace body 12 is cut along a plane perpendicular to the conveying direction D1, the height H31 of the temperature maintaining space 34 is higher than the height H11 of the first preheating space 50 and is approximately the same as the height H21 of the second preheating space 52 at the boundary between the second preheating space 52 and the temperature maintaining space 34. The height H32 from the conveying surface 28 to the floor wall 12b in the temperature maintaining space 34 is approximately constant in the conveying direction D1. When the furnace body 12 is cut along a plane perpendicular to the conveying direction D1, the height H32 of the temperature maintaining space 34 is approximately the same as the height H12 of the first preheating space 50 and the height H22 of the second preheating space 52. In a modified example, the height H32 may be different from the height H12 and the height H22. In this configuration, the height H31 of the temperature maintaining space 34 may be the same as or different from the height H11 of the first preheating space 50 and the height H21 of the second preheating space 52. As shown in FIG. 3, when the furnace body 12 is cut along a plane perpendicular to the conveying direction D1, the furnace interior width W3 of the temperature maintaining space 34 is larger than the furnace interior width W1 of the first preheating space 50 and the furnace interior width W2 of the second preheating space 52. The furnace interior width W3 of the temperature maintaining space 34 is substantially constant in the conveying direction D1. When the furnace body 12 is cut along a plane perpendicular to the conveying direction D1, the cross-sectional area of ​​the temperature maintaining space 34 is larger than the cross-sectional area of ​​the first preheating space 50 and the cross-sectional area of ​​the second preheating space 52. The cross-sectional area of ​​the temperature maintaining space 34 is 1.1 times or more the cross-sectional area of ​​the first preheating space 50. The cross-sectional area of ​​the temperature maintaining space 34 is substantially constant in the conveying direction D1.

[0035] 4, the cooling space 36 includes a first cooling space 60, a second cooling space 62, and a third cooling space 64. The first cooling space 60, the second cooling space 62, and the third cooling space 64 are arranged in this order in the transfer direction D1. The first cooling space 60 communicates with the temperature maintenance space 34. The second cooling space 62 communicates with the first cooling space 60. The third cooling space 64 communicates with the second cooling space 62, the discharge port 20, and the second exhaust port 42.

[0036] The length L4 of the first cooling space 60 in the conveying direction D1 is longer than the length L0 of the workpiece 2. The length L4 of the first cooling space 60 is longer than the length L2 of the second preheating space 52 and shorter than the length L1 of the first preheating space 50 and the length L3 of the temperature maintaining space 34. The height H4 of the first cooling space 60 (i.e., the distance between the ceiling wall 12a and the floor wall 12b of the furnace body 12 in the vertical direction) is approximately constant in the conveying direction D1. The height H4 of the first cooling space 60 is the largest within the cooling space 36. When the furnace body 12 is cut along a plane perpendicular to the conveying direction D1, the height H4 of the first cooling space 60 is equal to or less than the height H1 of the first preheating space 50 and is shorter than the height H2 of the second preheating space 52 and the height H3 of the temperature maintaining space 34. The height H3 of the temperature maintaining space 34 is 1.1 times or more the height H4 of the first cooling space 60. Therefore, a step 68 is formed between the temperature maintaining space 34 and the first cooling space 60. This prevents the ambient gas in the temperature maintaining space 34 from flowing into the first cooling space 60. The height H41 from the conveying surface 28 to the ceiling wall 12a in the first cooling space 60 is substantially constant in the conveying direction D1. When the furnace body 12 is cut along a plane perpendicular to the conveying direction D1, the height H41 of the first cooling space 60 is equal to or less than the height H11 of the first preheating space 50 and is lower than the height H21 of the second preheating space 52 and the height H31 of the temperature maintaining space 34. The height H42 from the conveying surface 28 to the floor wall 12b in the first cooling space 60 is substantially constant in the conveying direction D1. When the furnace body 12 is cut along a plane perpendicular to the conveying direction D1, the height H42 of the first cooling space 60 is substantially the same as the height H32 of the temperature maintaining space 34. As shown in FIG. 3, when the furnace body 12 is cut along a plane perpendicular to the conveying direction D1, the furnace interior width W4 of the first cooling space 60 is smaller than the furnace interior width W1 of the first preheating space 50, the furnace interior width W2 of the second preheating space 52, and the furnace interior width W3 of the temperature maintaining space 34. Note that in FIG. 3, the first cooling space 60 is illustrated by a dashed line. The furnace interior width W4 of the first cooling space 60 is substantially constant in the conveying direction D1. When the furnace body 12 is cut along a plane perpendicular to the conveying direction D1, the cross-sectional area of ​​the first cooling space 60 is the largest within the cooling space 36. The cross-sectional area of ​​the first cooling space 60 is substantially constant in the conveying direction D1.The cross-sectional area of ​​the first cooling space 60 is equal to or smaller than the cross-sectional area of ​​the first preheating space 50 and smaller than the cross-sectional areas of the second preheating space 52 and the temperature maintaining space 34. Therefore, in the furnace body 12, the cross-sectional area of ​​the temperature maintaining space 34 is larger than the cross-sectional areas of the preheating space 32 and the cooling space 36. Therefore, even when the ambient gas flows through the temperature maintaining space 34, the atmosphere within the temperature maintaining space 34 is less likely to fluctuate, and temperature variations within the temperature maintaining space 34 are less likely to occur. This makes it possible to suppress variations in the amount of heat applied to the workpiece 2 within the temperature maintaining space 34. Furthermore, when the cross-sectional area of ​​the first cooling space 60 is smaller than the cross-sectional area of ​​the preheating space 32, the ambient gas within the temperature maintaining space 34 flows more easily through the preheating space 32. This makes it easier to adjust the temperature of the first cooling space 60. The cross-sectional area of ​​the temperature maintaining space 34 is 1.1 times or more the cross-sectional area of ​​the first cooling space 60. The cross-sectional area of ​​the first preheating space 50 is equal to or greater than the cross-sectional area of ​​the first cooling space 60 .

[0037] As shown in FIG. 4, the length L5 of the second cooling space 62 in the conveying direction D1 is longer than the length L0 of the workpiece 2 and is approximately the same as the length L4 of the first cooling space 60. The height H5 of the second cooling space 62 (i.e., the distance between the ceiling wall 12a and the floor wall 12b of the furnace body 12 in the vertical direction) is approximately constant in the conveying direction D1. When the furnace body 12 is cut along a plane perpendicular to the conveying direction D1, the height H5 of the second cooling space 62 is lower than the height H4 of the first cooling space 60. The height H5 of the second cooling space 62 is 0.9 times or less the height H4 of the first cooling space 60. The height H51 from the conveying surface 28 to the ceiling wall 12a in the second cooling space 62 is approximately constant in the conveying direction D1. When the furnace body 12 is cut along a plane perpendicular to the conveying direction D1, the height H51 of the second cooling space 62 is lower than the height H41 of the first cooling space 60. The height H51 of the second cooling space 62 is 0.9 times or less the height H41 of the first cooling space 60. The height H52 from the conveying surface 28 to the floor wall 12b in the second cooling space 62 is approximately constant in the conveying direction D1. When the furnace body 12 is cut along a plane perpendicular to the conveying direction D1, the height H52 of the second cooling space 62 is approximately the same as the height H42 of the first cooling space 60. As shown in FIG. 3, when the furnace body 12 is cut along a plane perpendicular to the conveying direction D1, the furnace interior width W5 of the second cooling space 62 is approximately the same as the furnace interior width W4 of the first cooling space 60. The furnace interior width W5 of the second cooling space 62 is approximately constant in the conveying direction D1. When the furnace body 12 is cut along a plane perpendicular to the conveying direction D1, the cross-sectional area of ​​the second cooling space 62 is smaller than the cross-sectional area of ​​the first cooling space 60. The cross-sectional area of ​​the first cooling space 60 is larger than the cross-sectional area of ​​the second cooling space 62. The cross-sectional area of ​​the second cooling space 62 is approximately constant in the transfer direction D1.

[0038] As shown in FIG. 4, the length L6 of the third cooling space 64 in the conveying direction D1 is longer than the length L0 of the workpiece 2, the length L4 of the first cooling space 60, and the length L5 of the second cooling space 62. The sum of the lengths L4, L5, and L6 (i.e., the length of the cooling space 36 in the conveying direction D1) is longer than the length of the preheating space 32 in the conveying direction D1 (i.e., the sum of the lengths L1 and L2) and the length L3 of the temperature maintaining space 34. The height H6 of the third cooling space 64 (i.e., the distance between the ceiling wall 12a and the floor wall 12b of the furnace body 12 in the vertical direction) is approximately constant in the conveying direction D1. The height H6 of the third cooling space 64 is lower than the height H5 of the second cooling space 62. The height H6 of the third cooling space 64 is 0.9 times or less the height H5 of the second cooling space 62. Therefore, the height of the cooling space 36 gradually decreases in the conveying direction D1 (i.e., toward the discharge port 20). The height H61 from the conveying surface 28 to the ceiling wall 12a in the third cooling space 64 is approximately constant in the conveying direction D1. When the furnace body 12 is cut along a plane perpendicular to the conveying direction D1, the height H61 of the third cooling space 64 is lower than the height H51 of the second cooling space 62. The height H61 of the third cooling space 64 is 0.9 times or less the height H51 of the second cooling space 62. The height H62 from the conveying surface 28 to the floor wall 12b in the third cooling space 64 is approximately constant in the conveying direction D1. When the furnace body 12 is cut along a plane perpendicular to the conveying direction D1, the height H62 of the third cooling space 64 is approximately the same as the height H52 of the second cooling space 62. As shown in FIG. 3, when the furnace body 12 is cut along a plane perpendicular to the conveying direction D1, the furnace interior width W6 of the third cooling space 64 is approximately the same as the furnace interior width W5 of the second cooling space 62. The furnace in-width W6 of the third cooling space 64 is approximately constant in the conveying direction D1. When the furnace body 12 is cut along a plane perpendicular to the conveying direction D1, the cross-sectional area of ​​the third cooling space 64 is smaller than the cross-sectional area of ​​the second cooling space 62. Therefore, the cross-sectional area of ​​the third cooling space 64 is the smallest in the cooling space 36 and also the smallest in the furnace body 12. The cross-sectional area of ​​the second cooling space 62 is larger than the cross-sectional area of ​​the third cooling space 64. The cross-sectional area of ​​the third cooling space 64 is approximately constant in the conveying direction D1.

[0039] (effect) In the first embodiment described above, when the furnace body 12 is cut along a plane perpendicular to the conveying direction D1, the cross-sectional area of ​​the temperature maintaining space 34 is larger than the cross-sectional area of ​​the preheating space 32. With this configuration, when the furnace body 12 is cut along a plane perpendicular to the conveying direction D1, the atmosphere in the temperature maintaining space 34 fluctuates less due to disturbances, and temperature variations in the temperature maintaining space 34 are less likely to occur, compared to a configuration in which the cross-sectional area of ​​the temperature maintaining space 34 is smaller than the cross-sectional area of ​​the preheating space 32. This makes it possible to suppress variations in the amount of heat applied to the workpiece 2 in the temperature maintaining space 34.

[0040] (Correspondence) The height H4 is an example of a "first height." The height H5 is an example of a "second height."

[0041] (Second Example) In the second embodiment, only the differences from the first embodiment will be described. As shown in FIG. 5, the preheating space 32 includes only the first preheating space 50, i.e., it does not include the second preheating space 52 of the first embodiment. The length L1 of the first preheating space 50 corresponds to the length of the preheating space 32 in the conveying direction D1. The first preheating space 50 communicates with both the carry-in entrance 18 and the temperature maintaining space 34. Because the height H3 of the temperature maintaining space 34 is greater than the height H1 of the first preheating space 50, a step 100 is formed between the temperature maintaining space 34 and the first preheating space 50.

[0042] Furthermore, the cooling space 36 only includes the first cooling space 60, i.e., it does not include the second cooling space 62 and the third cooling space 64 of the first embodiment. The first cooling space 60 communicates with both the temperature maintaining space 34 and the discharge port 20. The length L4 of the first cooling space 60 corresponds to the length of the cooling space 36 in the conveying direction D1, and is longer than both the length L3 of the preheating space 32 and the temperature maintaining space 34 in the conveying direction D1.

[0043] (Variation) In one embodiment, the cooling space 36 may not include the third cooling space 64. The cooling space 36 may further include N cooling spaces, where N is a natural number.

[0044] In one embodiment, when the furnace body 12 is cut along a plane perpendicular to the conveyance direction D1, the cross-sectional area of ​​the cooling space 36 may be substantially the same as the cross-sectional area of ​​the preheating space 32.

[0045] In one embodiment, when the furnace body 12 is cut along a plane perpendicular to the conveying direction D1, at least one of the cross-sectional areas of the first preheating space 50, the temperature maintenance space 34, the first cooling space 60, the second cooling space 62, and the third cooling space 64 may change in the conveying direction D1.

[0046] In one embodiment, when the furnace body 12 is cut along a plane perpendicular to the conveying direction D1, at least one of the furnace interior widths W1, W2, W3, W4, W5, and W6 may vary in the conveying direction D1. Alternatively, the furnace interior widths W1, W2, W3, W4, W5, and W6 may be substantially the same.

[0047] In one embodiment, at least one of the heights H1, H3, H4, H5, and H6 may vary in the conveying direction D1. Also, at least one of the heights H11, H31, H41, H51, and H61 may vary in the conveying direction D1. Furthermore, at least one of the heights H12, H22, H32, H42, H52, and H62 may vary in the conveying direction D1.

[0048] Although specific examples of the technology disclosed in this specification have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples exemplified above. Furthermore, the technical elements described in this specification or drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technology exemplified in this specification or drawings simultaneously achieves multiple objectives, and achieving one of those objectives itself has technical utility. [Explanation of symbols]

[0049] 2: Processing object 10:Heating furnace 12:Furnace body 12a: Ceiling wall 14:Transportation device 18: Loading entrance 20: Exit 22: Furnace space 28:Transport surface 32: Preheating space 34:Temperature maintenance space 36: Cooling space 50: First preheating space 52: Second preheating space 60: 1st cooling space 62:Second cooling space 64:Third cooling space D1: Transport direction H1, H2, H3, H4, H5, H6, H11, H12, H21, H22, H31, H32, H41, H42, H51, H52, H61, H62: Height L1, L2, L3, L4, L5, L6: Length W1, W2, W3, W4, W5, W6: Furnace width

Claims

1. A heating furnace for heating a workpiece, a furnace body having a loading entrance, a loading exit, and an interior space extending in a transport direction from the loading entrance to the loading exit; The object to be processed can be placed on a conveying surface, and a conveying device that conveys the object to be processed in the conveying direction is provided, The furnace space is a preheating space communicating with the inlet and preheating the object to be treated; a temperature maintaining space communicating with the preheating space, for heating the object to be treated, the temperature of the temperature maintaining space being maintained constant; a cooling space communicating with the temperature maintaining space and the discharge port, for cooling the object to be treated; A heating furnace, wherein when the furnace body is cut along a plane perpendicular to the conveying direction, the cross-sectional area of ​​the temperature maintaining space is larger than the cross-sectional area of ​​the preheating space.

2. 2. The heating furnace according to claim 1, wherein when the furnace body is cut along a plane perpendicular to the conveying direction, the cross-sectional area of ​​the temperature maintaining space is larger than the cross-sectional area of ​​the cooling space.

3. The heating furnace according to claim 2 , wherein when the furnace body is cut along a plane perpendicular to the conveying direction, the cross-sectional area of ​​the cooling space is smaller than the cross-sectional area of ​​the preheating space.

4. 3. The heating furnace according to claim 2, wherein when the furnace body is cut along a plane perpendicular to the conveying direction, the height of the temperature maintaining space is 1.1 times or more the height of the cooling space.

5. The heating furnace according to claim 4 , wherein the height of the cooling space decreases stepwise toward the discharge outlet.

6. The cooling space is a first cooling space having a first height; a second cooling space that is in communication with the first cooling space, is disposed in the transfer direction relative to the first cooling space, and has the second height; the second height is equal to or less than 0.9 times the first height, The heating furnace according to claim 5 , wherein the length of the first cooling space in the transport direction and the length of the second cooling space in the transport direction are each equal to or greater than the length of the workpiece in the transport direction.

7. 5. The heating furnace according to claim 4, wherein when the furnace body is cut along a plane perpendicular to the conveying direction, the width of the temperature maintaining space is larger than the width of the cooling space.

8. The preheating space includes a first preheating space, 2. The heating furnace according to claim 1, wherein when the furnace body is cut along a plane perpendicular to the conveying direction, the height of the temperature maintaining space is 1.1 times or more the height of the first preheating space.

9. the preheating space further includes a second preheating space communicating with the first preheating space and the temperature maintenance space; The height of the second preheating space gradually increases toward the temperature maintaining space, The heating furnace according to claim 8 , wherein the length of the second preheating space in the transport direction is equal to or greater than the length of the workpiece in the transport direction.

10. 9. The heating furnace according to claim 8, wherein when the furnace body is cut along a plane perpendicular to the conveying direction, the width of the temperature maintaining space is larger than the width of the preheating space.

11. The heating furnace according to claim 1 , wherein the cross-sectional area of ​​the temperature maintaining space is constant in the conveying direction.

Images