Heat treatment furnace

Abstract

To improve the heat treatment capacity of a heat treatment furnace while suppressing the temperature increase of an object to be treated.SOLUTION: A heat treatment furnace comprises: a furnace body provided with a carry-in port, a carry-out port and a treatment chamber; a conveyance device conveying a sheet-shaped object W to be treated bridged from the carry-in port to the carry-out port; and a heating device heating the object W conveyed within the treatment chamber by the conveyance device. The heating device comprises one or more heaters (26a, 26b, 28) provided with a heat generating part(s) 27 radiating electromagnetic waves in an infrared region to the object W to be treated. The one or more heaters are arranged along a conveyance passage of the object W to be treated. Each heat generating part 27 is placed in parallel with the surface or the rear face of the object W to be treated, and stretches in a width direction (Y direction) of the object W to be treated orthogonal to the conveyance passage. Provided that the dimension in the width direction of the object W to be treated is defined as Wd, and the dimension in the width direction of each heat generating part 27 is defined as Hd, Wd / Hd reaches the range of 0.20 to 0.80.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The technology disclosed in this specification relates to a heat treatment furnace that performs heat treatment on a workpiece. [Background technology]

[0002] In the heat treatment furnace disclosed in Patent Document 1, the workpiece is suspended from an inlet through a treatment chamber to an outlet. The workpiece is loaded into the treatment chamber from the inlet, heat-treated while being transported within the treatment chamber, and then transported out through the outlet. In this heat treatment furnace, the workpiece is guided by multiple guide rollers arranged within the treatment chamber, and is transported along a predetermined transport path within the treatment chamber. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2014 / 163175 Summary of the Invention [Problem to be solved by the invention]

[0004] In this type of heat treatment furnace, improvement of heat treatment capacity (e.g., dehydration rate in a drying furnace) is required to improve productivity. Furthermore, from the perspective of decarbonization, heat treatment furnaces with superior energy-saving performance are required. Generally, to improve heat treatment capacity, it is considered to increase the heater output and apply a large amount of thermal energy to the workpiece. However, simply increasing the heater output may cause the temperature of the workpiece to rise too much, resulting in deterioration of the quality of the workpiece. Furthermore, even if increasing the heater output improves heat treatment capacity, energy-saving performance will decrease if the thermal energy from the heater cannot be used efficiently for heat treatment. This specification discloses technology related to a heat treatment furnace that improves heat treatment capacity while suppressing a rise in the temperature of the workpiece and has excellent energy-saving performance. [Means for solving the problem]

[0005] The heat treatment furnace disclosed herein includes a furnace body, a transport device, and a heating device. The furnace body includes an inlet, an outlet, and a treatment chamber disposed between the inlet and the outlet. The transport device transports a sheet-like workpiece, suspended between the inlet and the outlet, from the inlet through the treatment chamber to the outlet. The heating device is disposed in the same space as the workpiece within the treatment chamber and heats the workpiece transported by the transport device. The heating device includes one or more heaters having a heat generating portion that radiates electromagnetic waves in the infrared region toward the workpiece. The one or more heaters are disposed along the transport path of the workpiece. The heat generating portion is disposed parallel to the front or back surface of the workpiece and extends in the width direction of the workpiece, perpendicular to the transport path. When the width dimension of the workpiece is Wd and the width dimension of the heat generating portion is Hd, Wd / Hd is in the range of 0.20 to 0.80.

[0006] In the heat treatment furnace, the heater of the heating device includes a heat-generating portion that radiates infrared electromagnetic waves toward the workpiece. Therefore, the workpiece can be irradiated with electromagnetic waves of an infrared wavelength suitable for heat treatment. Furthermore, the widthwise dimension of the heater's heat-generating portion is optimized for the widthwise dimension of the workpiece. That is, Wd / Hd is in the range of 0.20 to 0.80. This allows the electromagnetic waves radiated from the heat-generating portion to be effectively used for the heat treatment of the workpiece, reducing the amount of electromagnetic waves used for purposes other than heat treatment. This improves heat treatment capacity while suppressing temperature increases in the workpiece, and also improves energy-saving performance. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a vertical cross-sectional view of a heat treatment furnace according to a first embodiment. [Figure 2] Cross-sectional view of line II-II in Figure 1. [Figure 3] FIG. 2 is a cross-sectional view of the heater according to the first embodiment. [Figure 4] FIG. 2 is a cross-sectional view of an air intake pipe according to the first embodiment. [Figure 5]FIG. 2 is a diagram schematically showing the relationship between the dimensions inside the furnace, the width direction dimension of the workpiece, and the dimensions of the heater. DETAILED DESCRIPTION OF THE INVENTION

[0008] In the heat treatment furnace disclosed in this specification, Wd / Hd may be in the range of 0.25 to 0.65. Furthermore, Wd / Hd may be in the range of 0.30 to 0.50. With this configuration, it is possible to further improve energy-saving performance while improving heat treatment capacity.

[0009] In the heat treatment furnace disclosed herein, the furnace body may include a pair of side walls spaced apart in the width direction. The heat generating unit may include a first end portion disposed on one side of the pair of side walls and a second end portion disposed on the other side of the pair of side walls. When the distance between the first end portion and one of the pair of side walls is Ld1, Wd / Ld1 may be in the range of 0.32 to 0.74. When the distance between the second end portion and the other of the pair of side walls is Ld2, Wd / Ld2 may be in the range of 0.20 to 0.33. This configuration provides an appropriate distance between the heat generating unit and the side walls. The electromagnetic waves emitted from the heat generating unit are effectively used for heat treatment of the workpiece, improving heat treatment capacity and energy saving performance. Furthermore, the amount of electromagnetic waves used for purposes other than heat treatment can be reduced, thereby preventing the side walls from being heated to high temperatures by the electromagnetic waves emitted from the heat generating unit. As a result, it is possible to prevent the object from being heated by radiation from the sidewall (that is, to prevent the temperature of the object from increasing).

[0010] In the heat treatment furnace disclosed in this specification, Wd / Ld1 may be in the range of 0.35 to 0.55, and Wd / Ld2 may be in the range of 0.23 to 0.25. With this configuration, it is possible to further improve energy-saving performance while improving the heat treatment capacity.

[0011] The heat treatment furnace disclosed in this specification may further include a plurality of guide rollers disposed within the treatment chamber for guiding the workpieces transported by the transport device. The transport path may be defined by the plurality of guide rollers. With this configuration, the length of the transport path within the treatment chamber can be increased, thereby improving the efficiency of heat treatment of the workpieces.

[0012] In the heat treatment furnace disclosed herein, the workpiece may include a sheet-like film and a paste applied to at least one of the front and back surfaces of the film. The heating device may remove moisture contained in the paste. Because the film has a small dimension in the thickness direction, an increase in the film temperature can cause deterioration in the film quality. Therefore, by using the heat treatment furnace disclosed herein, it is possible to improve the heat treatment capacity (moisture removal rate) while suppressing an increase in the film temperature. [Example]

[0013] A heat treatment furnace 10 according to Example 1 will be described. The heat treatment furnace 10 of this example is a drying furnace (dehydration device) that removes moisture from a workpiece W (an example of an object to be treated). The workpiece W is a sheet that extends continuously in the longitudinal direction, such as a film used in liquid crystal displays, organic electroluminescence (EL) displays, batteries, etc. Such films (sheets) may contain moisture in the film itself, or, if the film is coated with a coating layer, the coating layer may contain moisture. For this reason, the moisture contained in the film is first removed, and then the dehydrated film is cut to a desired size to produce a final product. The heat treatment furnace 10 of this example can be used to remove moisture from such sheets.

[0014] The configuration of the heat treatment furnace 10 will be described below with reference to the drawings. As shown in Figures 1 and 2, the heat treatment furnace 10 includes a rectangular parallelepiped furnace body 12, a transport device 20 that carries the workpieces W into and out of the furnace body 12, heating devices (26, 28) that heat the workpieces W, and an air supply device (38, etc.) that supplies cooling gas to the surface of the workpieces W.

[0015] The furnace body 12 includes a lower wall 13, an upper wall 14 facing the lower wall 13, side walls 17 and 18 (see FIG. 2) connected at one end to the lower wall 13 and at the other end to the upper wall 14, and an entrance side wall 15 and an exit side wall 16 that close the ends of a processing chamber (19a, 19b) surrounded by these walls 13, 14, 17, and 18.

[0016] The bottom wall 13 is a rectangular plate in a plan view and is disposed below the processing chambers (19a, 19b). As shown in FIG. 1, the bottom wall 13 is provided with a plurality of exhaust ports 13a at approximately regular intervals in the x direction. Of the plurality of exhaust ports 13a, five exhaust ports 13a located in the center are disposed in positions facing guide rollers 24, which will be described later. Of the plurality of exhaust ports 13a, the exhaust port 13a located at one end in the x direction is disposed in a position close to the loading side wall 15. Of the plurality of exhaust ports 13a, the exhaust port 13a located at the other end in the x direction is disposed in a position close to the unloading side wall 15. Each of the plurality of exhaust ports 13a is connected to an exhaust fan 13b. When the exhaust fan 13b is operated, the ambient gas in the processing chambers (19a, 19b) is exhausted to the outside of the processing chambers (19a, 19b).

[0017] The upper wall 14 is a plate material having the same shape as the lower wall 13 and is disposed above the processing chambers (19a, 19b). Similar to the lower wall 13, the upper wall 14 is also provided with a plurality of exhaust ports 14a at approximately regular intervals in the x direction. Each of the exhaust ports 14a is disposed opposite a corresponding one of the exhaust ports 13a. Each of the exhaust ports 14a is connected to an exhaust fan 14b. When the exhaust fan 14b is operated, the ambient gas within the processing chambers (19a, 19b) is exhausted to the outside of the processing chambers (19a, 19b).

[0018] An inlet 15a is provided in the loading sidewall 15, and an outlet 15b is formed in the unloading sidewall 16. The inlet 15a and the outlet 15b are positioned at the same height and face each other. As is clear from FIG. 1, the processing chambers (19a, 19b) are disposed between the inlet 15a and the outlet 15b.

[0019] The inner surfaces of the walls 13, 14, 15, 16, 17, and 18 constituting the furnace body 12 (i.e., the surfaces facing the processing chambers (19a, 19b)) are mirror-finished. As a result, the reflectance of these surfaces for electromagnetic waves in the infrared region (more specifically, electromagnetic waves emitted by the heaters 26 and 28, which will be described later) is 50% or more. This allows the electromagnetic waves emitted by the heaters 26 and 28 to be efficiently irradiated onto the workpiece W.

[0020] The conveying device 20 includes an inlet roller 21 arranged outside the furnace body 12 near the inlet 15a, an outlet roller 25 arranged outside the furnace body 12 near the outlet 16a, and a plurality of guide rollers (22a, 22b, 22c, 24) arranged within the processing chamber (19a, 19b).

[0021] The workpiece W is wound around the carry-in entrance rollers 21. The workpiece W wound around the carry-in entrance rollers 21 is stretched from the carry-in entrance 15a through the processing chambers (19a, 19b) to the carry-out exit 16a. Specifically, the workpiece W is stretched from the carry-in entrance rollers 21 through the carry-in entrance 15a onto the guide rollers (22a, 22b, 22c, 24), and further stretched from the guide rollers (22a, 22b, 22c, 24) through the carry-out exit 16a onto the carry-out exit rollers 25.

[0022] The discharge outlet rollers 25 are rollers that wind up the workpiece W that is discharged from the processing chambers (19a, 19b). A drive unit (not shown) is connected to the discharge outlet rollers 25, and the drive unit drives the discharge outlet rollers 25 to rotate. When the discharge outlet rollers 25 rotate, the workpiece W wound around the discharge inlet rollers 21 is sent out into the processing chambers (19a, 19b). The workpiece W sent out from the discharge inlet rollers 21 is guided by the guide rollers (22a, 22b, 22c, 24) and moves along a predetermined transport path within the processing chambers (19a, 19b), and is sent out from the discharge outlet 16a to the outside of the processing chambers (19a, 19b) and wound up by the discharge outlet rollers 25. In other words, the guide rollers (22a, 22b, 22c, 24) define the transport path of the workpiece W within the processing chambers (19a, 19b).

[0023] The guide rollers (22a, 22b, 22c, 24) include a plurality of upper guide rollers (22a, 22b, 22c) arranged near the upper wall 14 and a plurality of lower guide rollers 24 arranged near the lower wall 13. In this embodiment, contact rollers that come into contact with the workpiece W are used as the guide rollers (22a, 22b, 22c, 24), but non-contact rollers that guide the workpiece W without contacting it can also be used.

[0024] The upper guide rollers (22a, 22b, 22c) are arranged at regular intervals in the x direction. Specifically, the upper guide roller 22a is arranged adjacent to the carry-in entrance 15a, and the upper guide roller 22c is arranged adjacent to the carry-out exit 16a. The multiple guide rollers 22b are arranged at equal intervals between the upper guide roller 22a and the upper guide roller 22c. The upper guide rollers (22a, 22b, 22c) are positioned at the same height.

[0025] Each of the multiple lower guide rollers 24 is disposed at a fixed interval in the x direction, similar to the upper guide rollers (22a, 22b, 22c). The interval in the x direction between adjacent lower guide rollers 24 is the same as the interval in the x direction between the upper guide rollers (22a, 22b, 22c). The positions of the multiple lower guide rollers 24 in the x direction are the center positions of the adjacent upper guides (22a, 22b, 22c). The positions of the multiple lower guide rollers 24 in the height direction are the same.

[0026] As described above, because the upper guide rollers (22a, 22b, 22c) and the lower guide rollers 24 are arranged, the workpiece W transported in the x direction from the carry-in entrance 15a is transported downward by the upper guide rollers 22a, then transported upward by the lower guide rollers 24, and thereafter repeatedly transported up and down by the upper transport rollers 22b and the lower transport rollers 24. Then, the workpiece W transported upward from the lower transport rollers 24 arranged closest to the carry-out exit 16a is transported toward the carry-out exit 16a by the upper guide rollers 22c. In this way, by repeatedly transporting the workpiece W up and down within the processing chambers (19a, 19b), the space within the processing chambers (19a, 19b) can be effectively utilized, and the processing time for drying the workpiece W can be secured. As is clear from FIG. 1, the processing chambers (19a, 19b) are divided into an upper processing chamber 19a provided on the upper wall 14 side and a lower processing chamber 19b provided on the lower wall 13 side by the workpiece W suspended on the guide rollers (22a, 22b, 22c, 24).

[0027] The heating device is disposed in the processing chamber (19a, 19b) and heats the workpiece W transported by the transport device 20. The heating device includes first heaters (26a, 26b) disposed near the guide rollers (22a, 22b, 22c, 24) and a second heater 28 disposed at a height between the upper guide rollers (22a, 22b, 22c) and the lower guide roller 24. As shown in FIG. 1, the first heaters (26a, 26b) and the second heater 28 are disposed along the transport path of the workpiece W.

[0028] The first heaters (26a, 26b) include a plurality of first upper heaters 26a arranged above the upper guide rollers (22a, 22b, 22c) and a plurality of first lower heaters 26b arranged below the lower guide rollers 24. Each of the first upper heaters 26a is arranged opposite a corresponding upper guide roller (22a, 22b, 22c), and each of the first lower heaters 26b is arranged opposite a corresponding lower guide roller 24. Therefore, the workpiece W is positioned between the first upper heater 26a and the upper guide rollers (22a, 22b, 22c), and is directly heated by the first upper heater 26a. Similarly, the workpiece W is positioned between the first lower heater 26b and the lower guide roller 24, and is directly heated by the first lower heater 26b.

[0029] Two second heaters 28 are arranged below each of the upper guide rollers (22a, 22b, 22c) with a gap in the z direction. Two second heaters 28 are arranged above each of the lower guide rollers 24 with a gap in the z direction. Therefore, eleven second heaters 28 are arranged with a gap in the x direction, and two second heaters 28 are arranged with a gap in the y direction. As is clear from the figure, the second heaters 28 are arranged at positions facing the workpiece W stretched over the upper guide rollers (22a, 22b, 22c) and the lower guide roller 24 (i.e., near the midpoint between adjacent guide rollers in the conveying direction of the workpiece W). Since the second heater 28 extends in the axial direction of the guide rollers (22a, 22b, 22c, 24), the entire width of the workpiece W stretched between the upper guide rollers (22a, 22b, 22c) and the lower guide roller 24 is heated by the second heater 28.

[0030] As shown in FIG. 2, the first heaters (26a, 26b) and the second heater 28 each extend through the sidewall 18 into the processing chamber (19a, 19b). The first heaters (26a, 26b) and the second heater 28 are each disposed parallel to the guide rollers (22a, 22b, 22c, 24) and extend in the axial direction (Y direction) of the guide rollers (22a, 22b, 22c, 24). The first heaters (26a, 26b) and the second heater 28 each include a heat-generating portion 27 that emits electromagnetic waves (thermal energy) in the infrared region and a non-heat-generating portion 29 that does not emit electromagnetic waves (thermal energy) in the infrared region. In other words, the heat-generating portion 27 contributes to the heat treatment of the workpiece W, while the non-heat-generating portion 29 does not contribute to the heat treatment of the workpiece W. In the heaters (26a, 26b, 28), the position in the axial direction (Y direction) at which thermal energy is radiated can be adjusted by adjusting the position of the heat generating portion 27 in the axial direction (Y direction).

[0031] As is clear from FIG. 2 , in the heaters (26a, 26b, 28), the heat-generating portion 27 is located in the middle in the axial direction, and the non-heat-generating portions 29 are located at both ends in the axial direction. That is, the heat-generating portion 27 is disposed between the two non-heat-generating portions 29. In this embodiment, the position of the heat-generating portion 27 is adjusted so as to face the workpiece W guided by the guide rollers (22a, 22b, 22c, 24). Specifically, the position is adjusted so that the center of the width direction (Y direction) of the workpiece W coincides with the center of the width direction (Y direction) of the heat-generating portion 27. Therefore, the heat-generating portion 27 is disposed parallel to the front or back surface of the workpiece W and faces the front or back surface of the workpiece W, and radiates electromagnetic waves (thermal energy) in the infrared region to the front or back surface of the workpiece W.

[0032] In this embodiment, where Wd is the width (Y direction) dimension of the workpiece W and Hd is the width (Y direction) dimension of the heat generating part 27, the ratio Wd / Hd is adjusted to be in the range of 0.20 to 0.80. That is, by setting Wd / Hd to 0.80 or less, the width (Y direction) dimension Hd of the heat generating part 27 is set to an appropriate length relative to the width (Y direction) dimension Wd of the workpiece W. This allows the heat generating part 27 to heat the entire width of the workpiece W, preventing uneven heating of the workpiece W in the width direction. Conversely, if Wd / Hd is set to be greater than 0.80, the edge of the workpiece W may not be heated sufficiently, and moisture may not be removed from the edge of the workpiece W. In such a case, measures such as lengthening the transport path for the workpiece W or reducing the transport speed may be required, resulting in a decrease in the energy-saving performance of the heat treatment furnace. On the other hand, by setting Wd / Hd to 0.2 or more, the widthwise (Y-direction) dimension Hd of the heat generating portion 27 does not become too much longer than the widthwise (Y-direction) dimension Wd of the workpiece W. This allows the electromagnetic waves radiated from the heat generating portion 27 to be effectively used for heat treatment of the workpiece W, improving the energy-saving performance of the heat treatment furnace. Furthermore, it is possible to prevent the furnace body 12 (specifically, the inner wall surfaces of the lower wall 13, upper wall 14, side walls 17, 18, entrance side wall 15, and exit side wall 16) from becoming too hot due to the electromagnetic waves radiated from the heat generating portion 27. Since it is possible to prevent the inner wall surfaces of the furnace body 12 from becoming too hot, it is possible to prevent the workpiece W from being heated by radiation from the inner wall surfaces of the furnace body 12, and therefore to prevent the workpiece W from becoming too hot. Note that Wd / Hd may be in the range of 0.25 to 0.65, or may be in the range of 0.30 to 0.50. By setting the numerical value range in this way, effective use of the electromagnetic waves emitted from the heat generating portion 27 is promoted, and energy saving performance can be further improved while improving the heat treatment capacity.

[0033] Furthermore, if the distance between the heat generating portion 27 and the side wall 17 (i.e., the side wall 17 on the side where the heaters (26a, 26b, 28) penetrate) (more specifically, the distance from the end (end in the -Y direction) of the heat generating portion 27 on the side wall 17 side to the side wall 17) is Ld1, Wd / Ld1 is adjusted to a range of 0.32 to 0.74. Similarly, if the distance between the heat generating portion 27 and the side wall 18 (i.e., the side wall 18 on the side where the heaters (26a, 26b, 28) do not penetrate) (more specifically, the distance from the end (end in the +Y direction) of the heat generating portion 27 on the side wall 18 side to the side wall 18) is Ld2, Wd / Ld2 is adjusted to a range of 0.20 to 0.33. In other words, by setting Wd / Ld1 to 0.32 or more, the distance between the heat generating portion 27 and the side wall 17 will not be too long. This prevents the furnace body 12 from becoming too large, and prevents a deterioration in thermal efficiency (i.e., a decrease in energy-saving performance). Furthermore, by setting Wd / Ld1 to 0.74 or less, the distance between the heat generating portion 27 and the side wall 17 does not become too short. This prevents the furnace body 12 (specifically, the inner wall surface of the side wall 17) from becoming too hot due to electromagnetic waves radiated from the heat generating portion 27. As a result, the workpiece W is prevented from being heated by radiation from the inner wall surface of the furnace body 12, and the workpiece W is prevented from becoming too hot. Similarly, by setting Wd / Ld2 to 0.20 or more, the distance between the heat generating portion 27 and the side wall 18 does not become too long. Furthermore, by setting Wd / Ld1 to 0.33 or less, the distance between the heat generating portion 27 and the side wall 17 does not become too short. This allows the electromagnetic waves radiated from the heat generating portion 27 to be effectively used for heat treatment of the workpiece W, improving energy-saving performance while improving heat treatment capacity.

[0034] As is clear from the above numerical ranges, the distance Ld1 from the side wall 17 to the heat generating portion 27 and the distance Ld2 from the side wall 18 to the heat generating portion 27 may be the same, or the distance Ld1 from the side wall 17 to the heat generating portion 27 may be shorter than the distance Ld2 from the side wall 18 to the heat generating portion 27. For example, in this embodiment, the ends of the heaters (26a, 26b, 28) on the side wall 17 side are located outside the furnace body 12, and a refrigerant (e.g., air) is supplied outside the furnace body 12 (see FIG. 2). As will be described later, the heaters (26a, 26b, 28) have a double-pipe structure including an inner pipe 32 and an outer pipe 34, and the refrigerant is supplied to a space 36 between the inner pipe 32 and the outer pipe 34 (see FIG. 3). Supplying the refrigerant to the heaters (26a, 26b, 28) outside the furnace body 12 prevents the refrigerant from excessively lowering the temperature inside the furnace and reducing the heat treatment capacity. Here, when the heat generating portion 27 is located at the center of the heaters (26a, 26b, 28) in the axial direction, the heat generating portion 27 is located near the side wall 17, and the distance Ld1 from the side wall 17 to the heat generating portion 27 is shorter than the distance Ld2 from the side wall 18 to the heat generating portion 27. The refrigerant supplied to the heaters (26a, 26b, 28) can be discharged from the end on the side wall 17 side.

[0035] Here, when the distance Ld1 from the side wall 17 to the heat generating portion 27 is shorter than the distance Ld2 from the side wall 18 to the heat generating portion 27, Wd / Ld1 may be in the range of 0.35 to 0.55, and Wd / Ld2 may be in the range of 0.23 to 0.25. By adjusting Wd / Ld2 to these ranges, the electromagnetic waves emitted from the heat generating portion 27 are more effectively used for the heat treatment of the workpiece W, thereby further improving the energy-saving performance of the heat treatment furnace 10. Note that when the end supplying the coolant to the heaters (26a, 26b, 28) is the end on the side wall 18 side, the end on the side wall 18 side may be positioned outside the furnace body 12 and the heat generating portion 27 may be positioned near the side wall 18, so that the distance Ld2 from the side wall 18 to the heat generating portion 27 is shorter than the distance Ld1 from the side wall 17 to the heat generating portion 27. In this case, Wd / Ld1 may be in the range of 0.20 to 0.33, preferably 0.23 to 0.25, and Wd / Ld2 may be in the range of 0.32 to 0.74, preferably 0.35 to 0.55. In addition, both the end of the heater (26a, 26b, 28) that supplies the refrigerant and the end that discharges the refrigerant may be located inside the furnace body 12.

[0036] The first heaters (26a, 26b) are known wavelength-controllable heaters that emit electromagnetic waves in the infrared region, and the heat generating portion 27 of the first heaters (26a, 26b) and the heat generating portion 27 of the second heater 28 have the same structure. Therefore, the structure of the heat generating portion 27 of the second heater 28 will be briefly described here.

[0037] As shown in FIG. 3 , the second heater 28 includes a filament 30, an inner tube 32 that houses the filament 30, and an outer tube 34 that houses the inner tube 32. The filament 30 is a heating element made of, for example, tungsten, and is supplied with power from an external power source (not shown). When power is supplied to the filament 30 and it reaches a predetermined temperature (e.g., 1200 to 1700°C), the filament 30 emits electromagnetic waves, including infrared rays. The inner tube 32 is made of an infrared-transmitting material that transmits only electromagnetic waves in a specific wavelength range (infrared range in this embodiment) of the electromagnetic waves emitted from the filament 30. By appropriately selecting the infrared-transmitting material for the inner tube 32, the wavelength of the electromagnetic waves emitted from the filament 30 to the outside of the inner tube 32 can be adjusted to a desired wavelength. The outer tube 34 is also made of the same infrared-transmitting material as the inner tube 32. Therefore, the electromagnetic waves that pass through the inner tube 32 pass through the outer tube 34 and are radiated to the outside. The space 36 between the inner tube 32 and the outer tube 34 serves as a refrigerant flow path through which a refrigerant (e.g., air) flows. By supplying the refrigerant to the space 36 (i.e., the refrigerant flow path), the temperature of the outer tube 34 is prevented from becoming too high. This prevents the workpiece W from overheating. Note that a wavelength-controllable heater that emits electromagnetic waves in the infrared region is disclosed in detail in, for example, Japanese Patent No. 4790092.

[0038] The air supply device includes a plurality of air supply pipes 38 extending in the y direction within the processing chambers (19a, 19b) and an air supply fan (not shown) disposed outside the processing chambers (19a, 19b) and supplying cooling gas to the plurality of air supply pipes 38. As shown in FIG. 4, the air supply pipes 38 are formed with two circumferential outlets 39a, 39b. Therefore, the cooling gas supplied from the air supply fan to the air supply pipes 38 is injected into the processing chambers (19a, 19b) from the outlets 39a, 39b. In this embodiment, the orientation of the air supply pipes 38 is adjusted so that the direction of injection of the cooling gas injected from the outlets 39a, 39b is perpendicular to the surface of the workpiece W. As shown in FIG. 4, the outlets 39a, 39b are disposed opposite each other across the axis of the air supply pipes 38. Therefore, when workpieces W are located on both the carry-in entrance 15a side and the carry-out exit 16a side of the air supply pipe 38, the cooling gas ejected from the nozzle holes 39a of the air supply pipe 38 is ejected onto one of the workpieces W, and the cooling gas ejected from the nozzle holes 39b of the air supply pipe 38 is ejected onto the other workpiece W. Also, as shown in Fig. 2, the nozzle holes 39a, 39b of the air supply pipe 38 are formed in plurality and spaced apart in the y direction. Therefore, the cooling gas ejected from the nozzle holes 39a, 39b is ejected onto the entire width of the workpiece W (y direction).

[0039] As shown in FIG. 1, two air supply pipes 38 are arranged below each of the upper guide rollers (22a, 22b, 22c) with a gap in the z direction. Also, two air supply pipes 38 are arranged above each of the lower guide rollers 24 with a gap in the z direction. As is clear from FIG. 1, the air supply pipes 38 are arranged at positions different from the positions at which the first heaters (26a, 26b) and the second heater 28 are arranged. Specifically, the second heaters 28 and the air supply pipes 38 are arranged alternately with equal gaps in the z direction (transport direction). As described above, the processing chambers (19a, 19b) are divided into the upper processing chamber 19a and the lower processing chamber 19b by the workpiece W stretched over the guide rollers (22a, 22b, 22c, 24), and an air supply pipe 38 is arranged in each of the upper processing chamber 19a and the lower processing chamber 19b.

[0040] The cooling gas supplied to the gas supply pipe 38 may be, for example, an inert gas, nitrogen, or Ar gas. The atmospheric gas in the processing chambers (19a, 19b) is adjusted by the gas injected into the processing chambers (19a, 19b) from the gas supply pipe 38. In this embodiment, in order to remove moisture contained in the workpieces W, the atmospheric gas in the processing chambers (19a, 19b) is adjusted to a gas having a dew point of 0°C or less. Note that the cooling gas may be air having a dew point of 0°C or less.

[0041] The controller 44 is configured by a processor equipped with a CPU, ROM, and RAM, and controls the conveying device 20, the heating devices (26, 28), and the air supply device. Specifically, the controller 44 controls the conveying speed and tension of the workpiece W by controlling the conveying device 20, controls the heating devices (26, 28) to control the amount of heat applied to the workpiece W, and controls the flow rate and speed of the cooling gas sprayed from the air supply pipe 38 to the workpiece W by controlling the air supply device.

[0042] The heat treatment furnace 10 is provided with a threading device for setting the workpiece W wound around the inlet rollers 21 onto the outlet rollers 25. As shown in FIG. 1, the threading device includes a chain 42 that circulates through the inside and outside of the treatment chambers (19a, 19b) and a drive device (not shown) that drives the chain 42. Like the workpiece W stretched across the guide rollers (22a, 22b, 22c, 24), the chain 42 extends from the inlet 15a to the outlet 16a while changing direction in the vertical direction, and then returns to the inlet 15a by passing from the outlet 16a outside the treatment chambers (19a, 19b). As shown in FIG. 1, the path along which the chain 42 is stretched intersects with the path along which the workpiece W is stretched (i.e., the transport path of the workpiece W) at multiple points. The position at which the chain 42 is positioned is on the outside of the width direction (y direction) of the workpiece W, so there is no interference between the chain 42 and the workpiece W (see FIG. 2). To set the workpiece W on the discharge-outlet rollers 25 using the threading device, first, the workpiece W wound around the discharge-inlet rollers 21 is clamped by a clamp (not shown) attached to the chain 42. Next, the drive device circulates the chain 42, and the workpiece W is sent out from the discharge-inlet rollers 21. As a result, the workpiece W held by the clamp on the chain 42 moves together with the chain 42 within the processing chamber (19a, 19b) and moves to the discharge-outlet 16a. Once the workpiece W has reached the discharge-outlet 16a, the clamp is operated to release the workpiece W from the chain 42, and the workpiece W is set on the discharge-outlet rollers 25. Finally, the exit rollers 25 are rotated to apply tension to the workpiece W, so that the workpiece W is stretched from the entrance 15a to the exit 16a via the guide rollers (22a, 22b, 22c, 24).

[0043] Next, a process for removing moisture from the workpiece W using the heat treatment furnace 10 described above will be described. First, cooling gas is supplied from the air supply pipe 38 into the treatment chambers (19a, 19b) to adjust the interior of the treatment chambers (19a, 19b) to a predetermined atmosphere. Next, the controller 44 drives the transfer device 20 to transfer the workpiece W from the inlet 15a through the treatment chambers (19a, 19b) to the outlet 16a. At this time, the controller 44 controls the heating devices (26, 28) to irradiate the workpiece W with electromagnetic waves in the infrared range and to eject cooling gas from the air supply pipe 38 onto the surface of the workpiece W. When the heating devices (26, 28) irradiate the infrared electromagnetic waves, the moisture contained in the workpiece W absorbs the irradiated electromagnetic waves, and the moisture evaporates. The moisture evaporated from the workpiece W is removed from the surface of the workpiece W by the cooling gas ejected from the air supply pipe 38. The atmospheric gas containing the moisture removed from the surface of the workpiece W is exhausted to the outside of the processing chamber (19a, 19b) through the exhaust port 13a in the lower wall 13 and the exhaust port 14a in the upper wall 14. The moisture is removed from the workpiece W while it is transported from the carry-in port 15a to the carry-out port 16a. The workpiece W from which the moisture has been removed is taken up by the carry-out port rollers 25.

[0044] Here, an example of the measurement results of the heat treatment capacity and energy-saving performance when heat treating the workpiece W using the heat treatment furnace 10 according to this embodiment will be described with reference to Table 1. As shown in Table 1, for a width dimension of the workpiece W of 120 mm, the heater heat generation length Hd was varied from 120 mm to 1100 mm, the distance Ld1 from the side wall 17 to the heat generating portion 27 was varied from 8 mm to 403 mm, and the distance Ld2 from the side wall 18 to the heat generating portion 27 was varied from 20 mm to 605 mm. The total length of the heater was 984 mm, and the effective furnace dimension Td was 1128 mm. The heating time of the workpiece W was set to 15 seconds, and the intake air volume was adjusted so that the temperature of the workpiece W was 150°C. As shown in the experimental results, in Comparative Examples 1 and 2, the dehydration rate was 50%, but the input energy to the heater needed to be increased, resulting in a decrease in energy-saving performance. In Comparative Example 3, the input energy to the heater was reduced, but the dehydration rate was reduced to 30%. In particular, dehydration was insufficient at the ends of the workpiece W. On the other hand, in Examples 1 to 6, the dehydration rate was 30% or more while reducing the input energy to the heater. In particular, in Examples 3 and 4, the dehydration rate was 50% or more while reducing the input energy to the heater, thereby achieving both a high dehydration rate and energy-saving performance.

[0045] [Table 1]

[0046] In the heat treatment furnace 10 described above, the widthwise dimension of the heat generating portion 27 of the heater (26a, 26b, 28) is adjusted to be appropriate for the widthwise dimension of the workpiece W. Furthermore, the distance from the heat generating portion 27 of the heater (26a, 26b, 28) to the sidewall (17 and / or 18) is adjusted to be appropriate. This allows the electromagnetic waves emitted from the heat generating portion 27 of the heater (26a, 26b, 28) to be efficiently used to remove moisture from the workpiece W, improving the dehydration rate of the workpiece W (the heat treatment capacity of the heat treatment furnace 10) and improving the energy-saving performance of the heat treatment furnace 10. Furthermore, the electromagnetic waves emitted from the heat generating portion 27 are prevented from becoming too hot on the inner wall surface of the furnace body 12, thereby suppressing the temperature rise of the workpiece W. This prevents quality deterioration due to the temperature rise of the workpiece W, while improving the heat treatment capacity and energy-saving performance of the heat treatment furnace 10.

[0047] In the above embodiment, the heat generating portion 27 of the first heater (26a, 26b) and the heat generating portion 27 of the second heater 28 are the same in length, but this is not a limitation. That is, the length of the heat generating portion of the heater may be different depending on the location in the processing chamber. For example, as shown in FIG. 1, the first heater (26a, 26b) is disposed between the guide rollers (22a, 22b, 22c, 24) and the upper wall 14 or the lower wall 13, while the second heater 28 is disposed between the entrance side wall 15 and the exit side wall 16. As is clear from the drawing, the first heater (26a, 26b) is disposed close to the upper wall 14 or the lower wall 13, and the second heater 28 is disposed far from the entrance side wall 15 and the exit side wall 16. Therefore, the length of the heat generating portion 27 of the first heater (26a, 26b) may be shorter than the length of the heat generating portion 27 of the second heater 28. This may reduce the heat energy radiated from the heat generating portion 27 of the first heater (26a, 26b), suppress heating of the upper wall 14 or the lower wall 13, and suppress a rise in the temperature of the workpiece W. On the other hand, the heat energy radiated from the heat generating portion 27 of the second heater 28 may be increased to improve the dehydration rate of the workpiece W.

[0048] In the above embodiment, the guide rollers (22a, 22b, 22c, 24) are used to switch the transport direction of the workpiece W between up and down, but this is not a limitation. For example, the guide rollers within the processing chamber may be eliminated, and the workpiece may be transported linearly within the processing chamber from the carry-in entrance rollers to the carry-out exit rollers.

[0049] Furthermore, in the above embodiment, the length of the heat generating portion 27 of the heaters (26a, 26b, 28) is constant, but the length of the heat generating portion may be variable depending on the width dimension of the workpiece W. For example, filaments of different lengths may be installed, and the length of the heat generating portion may be changed by changing the filament to which power is supplied.

[0050] The technical elements described in this specification or drawings may 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 technologies illustrated in this specification or drawings simultaneously achieve multiple objectives, and achieving one of those objectives is itself technically useful. [Explanation of symbols]

[0051] 10: Heat treatment furnace 12:Furnace body 13: Lower wall 14: Upper wall 15: Carry-in side wall 16: Carry-out side wall 17,18: Side wall 19a, 19b: Processing chamber 20: Transport device 22a, 22b, 22c, 24 ; guide rollers 26a, 26b: First heater 27: Heat generating part 28: Second heater 29: Non-heat-generating part 30: Filament 32: Inner tube 34:Outer tube 36: Space 38: Air supply pipe 39a:Blowout hole 42: Chain 44: Controller W: Work (processing object)

Claims

1. a furnace body including a loading port, a loading port, and a processing chamber disposed between the loading port and the loading port; a conveying device that conveys a sheet-like object to be processed, which is stretched from the inlet to the outlet, from the inlet through the processing chamber to the outlet; a heating device that is arranged in the same space as the space in the processing chamber where the workpiece is transported, and that heats the workpiece transported by the transport device, the heating device includes one or more heaters each having a heat generating portion that radiates electromagnetic waves in the infrared region toward the workpiece; the one or more heaters are arranged along a transport path of the workpiece, the heat generating portion is disposed parallel to the front or rear surface of the workpiece and extends in a width direction of the workpiece that is perpendicular to the transport path, The center of the workpiece in the width direction and the center of the heat generating portion in the width direction coincide with each other, A heat treatment furnace, wherein Wd / Hd is in the range of 0.20 to 0.80, where Wd is the dimension of the workpiece in the width direction and Hd is the dimension of the heat generating portion in the width direction.

2. 2. The heat treatment furnace according to claim 1, wherein the Wd / Hd is in the range of 0.25 to 0.

65.

3. 2. The heat treatment furnace according to claim 1, wherein the Wd / Hd is in the range of 0.30 to 0.

50.

4. The furnace body includes a pair of side walls spaced apart in the width direction, the heat generating portion has a first end portion disposed on one side of the pair of side walls and a second end portion disposed on the other side of the pair of side walls, When the distance between the first end portion and one of the pair of side walls is Ld1, Wd / Ld1 is in the range of 0.32 to 0.74, 2. The heat treatment furnace according to claim 1, wherein when the distance between the second end and the other of the pair of side walls is Ld2, Wd / Ld2 is in the range of 0.20 to 0.

33.

5. The Wd / Ld1 is in the range of 0.35 to 0.55, 5. The heat treatment furnace according to claim 4, wherein the Wd / Ld2 is in the range of 0.23 to 0.

25.

6. a plurality of guide rollers disposed within the processing chamber and configured to guide the object to be processed transported by the transport device; 6. The heat treatment furnace according to claim 1, wherein the transport path is defined by the plurality of guide rollers.

7. the object to be processed comprises a sheet-like film and a paste applied to at least one of the front and back surfaces of the film, The heat treatment furnace according to claim 6 , wherein the heating device removes moisture contained in the paste.

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