TW201510451A - Drying furnace - Google Patents

Abstract

A drying furnace (10) provided with: an infrared-ray heater (30); a selectively reflective layer (37) that is positioned, within a furnace body (12), between a filament (31) and a coating film (82), reflects at least part of an infrared ray having a wavelength of less than 2[mu]m, and transmits at least part of an infrared ray having a wavelength of 2-4[mu]m; and an infrared-ray absorbing plate (70) that is positioned within the furnace body (12) at the opposite side of the filament (31) to the selectively reflective layer (37), and can absorb at least part of an infrared ray having a wavelength of less than 2[mu]m. The infrared-ray heater (30) includes a second outer tube (35) that transmits at least part of an infrared ray having a wavelength of 2-4[mu]m, and surrounds the filament (31). At least one of the inner peripheral surface and the outer peripheral surface of the second outer tube (35) includes the selectively reflective layer (37) in a region containing the opposite side of the filament (31) to the infrared-ray absorbing plate (70).

Description

Drying furnace

The present invention relates to a drying oven.

Conventionally, a drying furnace that dries a drying target such as a coating film using an infrared heater has been known. For example, Patent Document 1 describes a drying furnace using an infrared heater including a heating element, an inner tube surrounding the heating element, and an outer tube. In this drying furnace, the inner tube and the outer tube of the infrared heater function as a filter that transmits infrared rays having a wavelength of 3.5 μm or less and absorbs infrared rays having a wavelength exceeding 3.5 μm. The infrared ray having a wavelength of 3.5 μm or less is excellent in the performance of cutting hydrogen bonds, and infrared rays of this wavelength are radiated to a drying target, and drying can be performed efficiently.

[Prior patent documents]

[Patent Literature]

[Patent Document 1] Japanese Patent No. 4790092

However, in the case of drying in a drying oven using such an infrared heater, infrared rays having a wavelength of less than 2 μm may be emitted from the infrared heater. When the infrared ray having a wavelength of less than 2 μm is emitted, the infrared ray may cause overheating, for example, in the furnace body or the drying target of the drying furnace. When the dry object becomes overheated, for example, a large amount of cooling is required. Air is supplied, and there is a case where the energy consumed during drying increases.

The present invention has been developed in order to solve such a problem, and its main object is to further suppress overheating of a drying object caused by infrared rays having a wavelength of less than 2 μm from an infrared heater.

The drying furnace of the present invention comprises: a furnace body for drying the drying object; an infrared heater disposed in the furnace body and having a heating element for radiating electromagnetic waves containing infrared rays; and the selective reflector is attached to the furnace The body is disposed between the heating element and the object to be dried, and reflects at least a part of infrared rays having a wavelength of less than 2 μm, and transmits at least a part of infrared rays having a wavelength of 2 μm to 4 μm; and the infrared absorber is disposed in the furnace body. At least a part of the infrared rays having a wavelength of less than 2 μm can be absorbed on the side opposite to the selective reflection system when viewed from the heat generating body.

In the drying furnace of the present invention, when an electromagnetic wave containing infrared rays is radiated from the heat generating body of the infrared heater, the infrared rays having a wavelength of less than 2 μm in the electromagnetic wave are reflected by the selected reflector in the direction of the drying target. Therefore, it is possible to suppress infrared rays having a wavelength of less than 2 μm from reaching the object to be dried in a straight line. Further, the infrared ray reflected by the selected reflector is radiated from the selective reflector to the heat generating body side, but is absorbed by the infrared absorbing body. Therefore, it is also possible to suppress the infrared rays reflected by the selected reflector from being reflected by the furnace body or the like to reach the drying target side. According to the above, it is possible to further suppress overheating of the drying target caused by infrared rays having a wavelength of less than 2 μm from the infrared heater. Further, since the infrared ray having a wavelength of 2 μm to 4 μm radiated from the infrared heater can be passed to the object to be dried after passing through the selection of the reflector, the object to be dried can be dried by the infrared ray. In this case, The reflection system is selected to transmit at least a part of the infrared rays having a wavelength of from 2 μm to 3.5 μm. Infrared rays having a wavelength of 3.5 μm or less are excellent in the performance of hydrogen bonding in molecules such as water or solvent, so that the infrared rays are transmitted by selecting a reflector, and the object to be dried can be dried more efficiently. Further, it is also possible to select not only the infrared ray having a wavelength of less than 2 μm but also at least a part of the electromagnetic wave having a wavelength shorter than the infrared ray of less than 0.7 μm. In this case, the infrared absorbing system may also absorb at least a part of electromagnetic waves having a wavelength shorter than infrared rays and less than 0.7 μm. Further, the selective reflector and the infrared ray absorbing system may be in the form of a layered (film-like) formed on the surface of another member, or may be in the form of an independent member.

In this case, it is preferable that the transmittance of infrared rays having a reflection system wavelength of 2 μm to 4 μm is higher than that of infrared rays having a wavelength of less than 2 μm. In addition, "the transmittance of infrared rays having a wavelength of 2 μm to 4 μm is higher than the transmittance of infrared rays having a wavelength of less than 2 μm", which is a total transmittance of infrared rays having a wavelength of 2 μm to 4 μm than that of infrared rays having a wavelength of less than 2 μm. In addition to the higher case, the range of the wavelength higher than the total transmittance of infrared rays having a wavelength of less than 2 μm is included in the range of 2 μm to 4 μm. For example, the total transmittance of infrared rays having a wavelength of less than 2 μm may be 20% or less, and the total transmittance of infrared rays having a wavelength of 2 μm to 4 μm may be 80% or more. Further, it is also possible to select a reflector having a total transmittance of 80% or more of infrared rays having a wavelength of 2 μm to 3.5 μm.

In the drying furnace of the present invention, the infrared heater may have a tubular member that transmits at least a part of infrared rays having a wavelength of 2 μm to 4 μm and surrounds the heat generating body, and the tubular member is at least one of an inner peripheral surface and an outer peripheral surface. in The selective reflection body is included in a region on the side opposite to the infrared absorption system when viewed from the heat generating body. In this manner, the selective reflector is not disposed in the furnace as a member different from the infrared heater, and the overheating of the drying target caused by the infrared rays having a wavelength of less than 2 μm from the infrared heater can be further suppressed.

In this case, the infrared heater includes: a first tube that transmits at least a part of infrared rays having a wavelength of 2 μm to 4 μm and surrounds the heat generating body; and a second tube that surrounds the heat generating body and the tubular portion of the first tube In the at least one of the inner circumferential surface and the outer circumferential surface, the first tube has a reflection layer that reflects at least a part of infrared rays having a wavelength of 2 μm to 4 μm in a region on the side opposite to the drying target when viewed from the heating element. . In this manner, the infrared ray having a wavelength of 2 μm to 4 μm reflected from the electromagnetic wave radiated from the heat generating body of the infrared heater in the opposite direction to the drying target is reflected by the reflective layer. Therefore, the infrared rays of this wavelength can be efficiently irradiated to the object to be dried, and the drying efficiency is improved.

The drying furnace of the present invention may further include a partition wall in which a space in which the infrared heater is disposed and a space in which the object to be dried is disposed, and at least a part of infrared rays having a wavelength of 2 μm to 4 μm are transmitted through the furnace body. The partition has the selective reflector. In this way, since the space in which the infrared heater is disposed is separated from the space in which the object to be dried is disposed, even in the space of the former, the object in the space, the furnace body facing the space, or the like, the infrared light having a wavelength of less than 2 μm In the case of overheating, it is difficult for the dry object to become overheated. Therefore, it is possible to further suppress overheating of the object to be dried due to infrared rays having a wavelength of less than 2 μm from the infrared heater. Here, "the partition has the selective reflector" means a case where the entire partition is a selective reflector. Further, the partition wall may be a one having a selective reflector on the entire surface.

In the drying furnace of the present invention including the form of the above-mentioned partition wall, the furnace system may have the infrared absorber on the inner peripheral surface. In this manner, the infrared absorbing body is not disposed as an independent member in the furnace body, and the infrared ray absorbing body absorbs the infrared ray reflected by the selected reflector.

In the drying furnace of the present invention, the infrared absorbing system may have a refrigerant flow path through which the refrigerant can flow. In this manner, since the infrared absorber can be cooled by the refrigerant, the infrared absorber can be further prevented from absorbing infrared rays and becoming overheated, and the adverse effect of the overheating of the infrared absorber on the object to be dried (for example, overheating of the object to be dried) can be further suppressed.

10, 110‧‧‧ drying oven

12‧‧‧ furnace body

12a‧‧‧ Space

13‧‧‧ front end

14‧‧‧ rear end face

15, 16‧‧‧ openings

17, 18‧‧‧ Roll

19‧‧‧Transportation

20‧‧‧ gas supply

21‧‧‧Air supply fan

22‧‧‧ tube structure

23‧‧‧ gas supply port

25‧‧‧Exhaust device

26‧‧‧Exhaust fan

27‧‧‧ tube structure

28‧‧‧Exhaust port

30, 130‧‧‧ Infrared heater

31‧‧‧ filament

31a‧‧‧Electric wiring

32‧‧‧Inside

33‧‧‧ heater body

34‧‧‧1st outer tube

35‧‧‧2nd outer tube

36‧‧‧reflective layer

37, 137‧‧‧Select reflective layer

39‧‧‧Refrigerant flow path

40‧‧‧Cap

42~43‧‧‧Cylinder

44‧‧‧ Cover

45‧‧‧ bracket

47‧‧‧Wiring pull out

48‧‧‧ Fluid inlet and outlet

49‧‧‧temperature sensor

50‧‧‧Power supply

60‧‧‧1st refrigerant supply source

61‧‧‧Opening and closing valve

62‧‧‧Flow adjustment valve

65‧‧‧2nd refrigerant supply source

66‧‧‧Opening and closing valve

67‧‧‧Flow adjustment valve

70‧‧‧Infrared absorption board

78‧‧‧ Fluid inlet and outlet

79‧‧‧Refrigerant flow path

80‧‧‧Sheet

82‧‧·coating film

90‧‧‧ Controller

170‧‧‧Infrared absorption layer

185‧‧‧ partition

Fig. 1 is a longitudinal sectional view of the drying furnace 10.

Fig. 2 is a cross-sectional view along the line A-A showing a cross section of the infrared heater 30 and the infrared absorbing plate 70 of Fig. 1.

Fig. 3 is an explanatory view showing an example of wavelength characteristics of infrared rays radiated from the infrared heater 30.

Fig. 4 is a longitudinal sectional view of a drying furnace 110 according to a modification.

Next, an embodiment of the present invention will be described using the drawings. Fig. 1 is a longitudinal sectional view showing a drying furnace 10 according to an embodiment of the present invention. The drying furnace 10 performs drying of the coating film 82 to be dried, which is applied to the sheet 80 by infrared rays, and includes a furnace body 12, a gas supply device 20, an exhaust device 25, an infrared heater 30, and an infrared absorption plate 70. And controller 90. Further, the drying furnace 10 includes a roller 17 disposed in front of the furnace body 12 (on the left side of FIG. 1), and is provided on The roller 18 behind the furnace body 12 (on the right side of Fig. 1). This drying furnace 10 is constituted by a roll-to-roll drying furnace in which the sheet 80 on which the coating film 82 has been formed is continuously conveyed by the rollers 17 and 18 and dried.

The furnace body 12 is used to dry the coating film 82. The furnace body 12 is a heat insulating structure having a substantially rectangular parallelepiped shape, and has a space 12a for a space inside the furnace, and an opening 15 formed in the front end surface 13 and the rear end surface 14 of the furnace body, respectively, and opening and exiting from the outside to the space 12a. 16. The length of the furnace body 12 from the front end surface 13 to the rear end surface 14 is, for example, 2 to 10 m. The furnace body 12 includes a handling passage 19 that is a passage from the opening 17 to the opening 18. The conveyance path 19 penetrates the furnace body 12 in the horizontal direction. The sheet 80 on which the coating film 82 is applied on one side gradually passes through the conveyance path 19.

The air supply device 20 is a device that supplies (steams) fluid to the surface side of the sheet 80 to cool the coating film 82 or the sheet 80 in the furnace body 12. The air supply device 20 includes an air supply fan 21, a pipe structure 22, and an air supply port 23. The air supply fan 21 is attached to the pipe structure 22, and supplies a fluid to the inside of the pipe structure 22. The flow system can cool the cold air of the sheet 80, for example, air at normal temperature or below 50 °C. The air supply fan 21 can adjust the flow rate or temperature of the fluid. The pipe structure 22 serves as a passage for the fluid from the air supply fan 21. The pipe structure 22 forms a passage from the ceiling of the furnace body 12 to the inside of the furnace body 12 from the air supply fan 21. The air supply port 23 is a supply port of the fluid from the air supply fan 21 to the furnace body 12. The air supply port 23 is provided at the end of the furnace body 12 on the side of the opening 16 on the carrying-out side of the sheet 80, and is horizontally opened toward the opening 15 side of the loading side. Thereby, the air supply device 20 supplies the fluid in a direction opposite to the conveyance direction of the sheet 80 (in the left direction of the first drawing).

The exhaust unit 25 is a device that discharges the ambient gas in the furnace body 12. The exhaust device 25 includes an exhaust fan 26, a pipe structure 27, and an exhaust port 28. The exhaust port 28 is provided in the furnace body 12 at the end on the opening 15 side of the loading side of the sheet 80, and is horizontally opened toward the opening 16 side of the carry-out side. The exhaust port 28 is attached to the pipe structure 27, and is sucked into the atmosphere of the furnace body 12 (air supply from the air supply device 20 mainly flowing along the surface of the coating film 82) and guided into the pipe structure 27 . The pipe structure 27 serves as a flow path of the ambient gas from the exhaust port 28 to the exhaust fan 26. The pipe structure 27 forms a passage that passes through the ceiling of the furnace body 12 from the exhaust port 28 to the exhaust fan 26. The exhaust fan 26 is attached to the pipe structure 27 and discharges the atmosphere inside the pipe structure 27.

The infrared heater 30 is a device that irradiates infrared rays to the coating film 82 that has passed through the furnace body 12, and a plurality of them are mounted in the vicinity of the ceiling of the space 12a in the furnace body 12. In the present embodiment, the infrared heater 30 is disposed substantially evenly from the distal end surface 13 side to the rear end surface 14 side (in the present embodiment, six branches). The plurality of infrared heaters 30 have the same configuration and are mounted such that their longitudinal directions are orthogonal to the conveyance direction of the coating film 82. Hereinafter, the configuration of one infrared heater 30 will be described.

Fig. 2 is a cross-sectional view along the line A-A showing a cross section of the infrared heater 30 and the infrared absorbing plate 70 of Fig. 1. Further, the cross section shown in Fig. 2 is cut into a surface that passes through the center line of the heater body 33. As shown in FIGS. 1 and 2, the infrared heater 30 includes a heater body 33 formed to surround the tungsten filament 31 with the inner tube 32, and is disposed outside the heater body 33 to surround the inner tube 32. The first outer tube 34 formed in the manner and the second outer side formed on the outer side of the first outer tube 34 and surrounding the first outer tube 34 The tube 35 and the cap 40 are attached to both ends of these members (Fig. 2). The space between the first outer tube 34 and the second outer tube 35 serves as a refrigerant flow path 39 through which a refrigerant (for example, air) can flow. Further, the infrared heater 30 includes a temperature sensor 49 (see FIG. 2) that detects the surface temperature of the second outer tube 35. The temperature sensor 49 is disposed on the side of the coating film 82 in the second outer tube 35 as shown in Fig. 2 (the lower side of Fig. 1 and Fig. 2). Further, the inner tube 32, the first outer tube 34, and the second outer tube 35 are arranged concentrically, and the filament 31 is located at the center of the circle.

The heater body 33 is supported by a bracket 45 whose both ends are disposed inside the cap 40. The heater main body 33 supplies electric power to the filament 31 from a power supply source 50 (see FIG. 2) disposed outside the furnace body 12. When the filament 31 is heated to a predetermined temperature (for example, 1200 to 1700 ° C), the radiation includes Infrared electromagnetic waves. The electromagnetic wave radiated by the filament 31 is not particularly limited, and is, for example, a peak wavelength in an infrared region (a region having a wavelength of 0.7 μm to 8 μm) or a near-infrared region (a region having a wavelength of 0.7 μm to 3.5 μm). In the present embodiment, an electromagnetic wave having a radiation peak wavelength of around 3.5 μm is used. The inner tube 32 is a tube having a circular cross section surrounding the filament 31, and is formed by a material that absorbs a part of electromagnetic waves radiated from the filament 31 and transmits infrared rays. Examples of the infrared ray transmissive material used for the inner tube 32 include yttrium, lanthanum, sapphire, calcium fluoride, yttrium fluoride, zinc selenide, zinc sulfide, sulphur selenide glass, and translucent alumina ceramics. There are quartz glass that allows infrared rays to pass through. In the present embodiment, the inner tube 32 is formed of quartz glass which absorbs infrared rays having a wavelength of more than 4 μm as one of electromagnetic waves and transmits infrared rays having a wavelength of 4 μm or less. Further, the inside of the inner tube 32 is a vacuum environment or a halogen atmosphere. The electric wiring 31a connected to the filament 31 is disposed through the cap The wiring pull-out portion 47 of 40 is airtightly pulled to the outside and connected to the power supply source 50. As shown in Fig. 2, the cap 40 is formed by integrally forming a disk-shaped cover 44 with the cylindrical portions 42 and 43 which are erected on the cover 44. The left and right ends of the first outer tube 34 and the second outer tube 35 are fixed to the cylindrical portions 42 and 43, respectively.

The first outer tube 34 and the second outer tube 35 are tubes formed by the above-described infrared ray transmissive material. In the present embodiment, the first outer tube 34 and the second outer tube 35 are formed of a quartz glass material that absorbs infrared rays having a wavelength of more than 4 μm and transmits infrared rays having a wavelength of 4 μm or less, similarly to the inner tube 32. Further, the first outer tube 34 and the second outer tube 35 can be cooled to, for example, 200 ° C or lower by the refrigerant flowing through the refrigerant flow path 39.

A reflective layer 36 is formed on the outer peripheral surface of the first outer tube 34. The reflection layer 36 is formed on the outer peripheral surface of the first outer tube 34 and includes a region on the side opposite to the coating film 82 (the upper side in the first drawing) when viewed from the filament 31, and is provided to cover only a part of the periphery of the filament 31. . In the present embodiment, the reflective layer 36 is completely covered with the upper half of the first outer tube 34. The reflective layer 36 is configured such that the filament 31 is located at a central position of a circle including an arc of its cross section. The reflective layer 36 is formed by an infrared reflective material that reflects at least a portion of the infrared rays emitted from the electromagnetic waves emitted from the filament 31. Examples of the infrared reflective material include gold, platinum, aluminum, and the like. In the present embodiment, the reflective layer 36 is formed of a material that reflects at least a part of infrared rays having a wavelength of 2 μm to 4 μm. The reflective layer 36 is formed by forming a film of the infrared reflecting material on the surface of the first outer tube 34 by a film forming method using coating drying, sputtering, CVD, or thermal spraying. Further, the reflective layer 36 faces the refrigerant flow path 39 and is cooled by the refrigerant flowing through the refrigerant flow path 39.

A selective reflection layer 37 is formed on the outer circumferential surface of the second outer tube 35. this The selective reflection layer 37 is disposed between the filament 31 and the coating film 82 in the space 12a of the furnace body 12. More specifically, the selective reflection layer 37 is formed on the outer peripheral surface of the second outer tube 35 and includes a region on the same side as the coating film 82 (the lower side in the first drawing) when viewed from the filament 31, and is provided only to be coated. A portion of the circumference of the filament 31. In the present embodiment, the selective reflection layer 37 is formed by completely covering the lower half of the second outer tube 35. The selective reflection layer 37 is configured such that the filament 31 is located at a center position of a circle including a circular arc of its cross section. The selective reflection layer 37 is formed by reflecting a selective reflection material that transmits at least a part of the infrared rays having a wavelength of less than 2 μm from the electromagnetic wave radiated from the filament 31 and transmits at least a part of the infrared rays having a wavelength of 2 μm to 4 μm. Thereby, the reflection layer 37 is selected to function as a filter that selectively transmits infrared rays having a wavelength of 2 μm to 4 μm. The selective reflection layer 37 is preferably one having a transmittance of infrared rays having a wavelength of from 2 μm to 4 μm and a transmittance of infrared rays having a wavelength of less than 2 μm. In the present embodiment, the selective reflection layer 37 has a total transmittance of 20% or less of infrared rays having a wavelength of less than 2 μm, and a total transmittance of infrared rays having a wavelength of 2 μm to 4 μm of 80% or more. Further, the selective reflection layer 37 may be such that electromagnetic waves having a wavelength exceeding 4 μm are transmitted, or electromagnetic waves having a wavelength exceeding 4 μm may be used. In the former case, the selective reflection layer 37 functions as a low-pass filter, and in the latter case, the selective reflection layer 37 functions as a band-pass filter. In the present embodiment, the selective reflection layer 37 is made to transmit electromagnetic waves having a wavelength exceeding 4 μm. The selective reflection layer 37 which can reflect electromagnetic waves in a specific wavelength region in this manner is selected, for example, by a film formation method in which a coating film containing a cholesteric liquid crystal material is applied onto the surface of the second outer tube 35 and dried and hardened. The reflective material is formed into a film and formed. Further, the film of the condensed liquid crystal may be gradually applied layer by layer to form a selective reflection material composed of a plurality of cholesteric liquid crystal layers as the selective reflection layer 37. turn off The formation of such a selective reflection material is described in, for example, Japanese Laid-Open Patent Publication No. 2012-181359.

The refrigerant flow path 39 is a space between the first outer tube 34 and the second outer tube 35, and the refrigerant can flow through the fluid inlet and outlet 48 provided in the cap 40. The refrigerant is a fluid such as air. The fluid inlet and outlet 48 is connected to a first refrigerant supply source 60 disposed outside the furnace body 12. The refrigerant supplied from the first refrigerant supply source 60 flows into the refrigerant flow path 39 from one of the fluid inlets and outlets 48, flows through the refrigerant flow path 39, and flows out from the other fluid inlet and outlet 48. The refrigerant flowing through the refrigerant flow path 39 functions to lower the temperature of the second outer tube 35 on the outer surface of the infrared heater 30 or the temperature of the first outer tube 34 or to adjust to an arbitrary temperature.

The infrared ray absorbing plate 70 is a member that absorbs the substantially rectangular parallelepiped of the infrared ray emitted from the infrared ray heater 30, and is mounted between the ceiling of the space 12a in the furnace body 12 and the infrared ray heater 30. In the present embodiment, six infrared ray absorbing plates 70 are disposed, and each of the infrared absorbing plates 70 is in one-to-one correspondence with the infrared ray heater 30, and is mounted between the corresponding infrared heater 30 and the ceiling of the furnace body 12. In other words, the infrared ray absorbing plate 70 is disposed on the side opposite to the selective reflection layer 37 when viewed from the filament 31 of the infrared heater 30 in the space 12a of the furnace body 12 (the upper side of the first drawing and the second drawing). The plurality of infrared absorbing plates 70 have the same configuration, and are mounted in the direction in which the growth direction is orthogonal to the conveyance direction. Hereinafter, the configuration of one infrared absorbing plate 70 will be described.

As shown in FIG. 1, the infrared ray absorbing plate 70 is formed such that the width in the front-rear direction (the width on the left and right in the first drawing) is larger than the outer diameter of the infrared heater 30. Further, the infrared absorbing plate 70 is disposed to cover the infrared heater 30 The region on the opposite side of the coating film 82 (the region directly above the infrared heater 30 in FIGS. 1 and 2). The infrared absorbing plate 70 is formed of an infrared absorbing material that can absorb at least a part of infrared rays having a wavelength of less than 2 μm. The infrared absorbing material used for the infrared ray absorbing plate 70 is, for example, a Si-SiC composite material (yttrium-impregnated SiC) obtained by immersing the melted Si in a porous body containing SiC. The infrared ray absorbing plate 70 is hollow inside, and the internal space becomes the refrigerant flow path 79. The refrigerant flow path 79 is a refrigerant that can flow through the fluid inlet and outlet 78 provided at two places of the infrared absorption plate 70. The refrigerant may be any fluid, and for example, a gas such as air may be used, or a liquid such as water may be used. In the present embodiment, the refrigerant is water. The fluid inlet and outlet 78 is connected to a second refrigerant supply source 65 disposed outside the furnace body 12. The refrigerant supplied from the second refrigerant supply source 65 flows into the refrigerant flow path 79 from one of the fluid inlets and outlets 78, flows through the refrigerant flow path 79, and flows out from the other fluid inlet and outlet 78. The refrigerant that has flowed through the refrigerant flow path 79 functions to lower the temperature of the infrared absorbing plate 70 that is heated to absorb infrared rays. Further, the infrared ray absorbing plate 70 can be cooled to, for example, 200 ° C or lower by the refrigerant flowing through the refrigerant flow path 79.

The sheet 80 is not particularly limited, and is, for example, a sheet made of a resin. In the present embodiment, a film made of a PET film is used. The sheet 80 is not particularly limited, and is, for example, 10 to 100 μm in thickness and 200 to 1000 mm in width. Moreover, the coating film 82 is applied to the upper surface of the sheet 80, and is used as a film for MLCC (Laminated Ceramic Capacitor), for example, after drying. The coating film 82 is, for example, a ceramic powder or a metal powder, an organic binder, and an organic solvent. The thickness of the coating film 82 is not particularly limited and is, for example, 20 to 1000 μm.

The controller 90 is constructed as a CPU-centric microprocessor. to make. The controller 90 outputs a control signal to the air supply fan 21 or the exhaust fan 26, controls the temperature and the air volume of the fluid supplied from the air supply port 23, or the row of the ambient gas of the control space 12a from the exhaust port 28. Gas volume. Further, the controller 90 inputs the temperature of the second outer tube 35 detected by the temperature sensor 49 of the thermocouple or outputs a control signal to the piping provided to the first refrigerant supply source 60 and the fluid inlet/outlet 48. The on-off valve 61 and the flow rate adjustment valve 62 in the middle or the flow rate of the refrigerant flowing through the refrigerant flow path 39 of the infrared heater 30 are individually controlled (refer to FIG. 2). In the same manner, the controller 90 outputs a control signal to the on-off valve 66 and the flow rate adjustment valve 67 provided in the middle of the pipe connecting the second refrigerant supply source 65 and the fluid inlet and outlet 78, or individually controls the refrigerant flow in the infrared absorption plate 70. The flow of refrigerant flowing on the road 79. Further, the controller 90 outputs a control signal for adjusting the magnitude of the power supplied from the power supply source 50 to the filament 31 to the power supply source 50, and individually adjusts the filament temperature of the infrared heater 30. Further, the controller 90 can adjust the passage time of the sheet 80 and the coating film 82 in the furnace body 12 or the tension acting on the sheet 80 and the coating film 82 by controlling the number of rotations of the roller 17 and the roller 18.

Next, a state in which the coating film 82 is dried using the drying furnace 10 configured as described above will be described. First, the controller 90 rotates the roller 17 and the roller 18 to start carrying the sheet 80. Thereby, the sheet 80 is gradually loosened from the roller 17 disposed at the left end of the drying furnace 10. Further, the sheet 80 is applied onto the upper surface of the coating film 82 by an applicator (not shown) just before being carried into the furnace body 12 from the opening 15. Then, the sheet 80 to which the coating film 82 has been applied is transferred into the furnace body 12. At this time, the controller 90 controls the air supply fan 21, the exhaust fan 26, the power supply source 50, the first refrigerant supply source 60, and the second refrigerant supply source 65. Thereby, the sheet 80 passes through the furnace body Between the spaces 12a of 12, the coating film 82 formed on the upper surface of the sheet 80 is dried by being irradiated with infrared rays from the infrared heater 30. At the same time, the cold air from the air supply device 20 cools the coating film 82 or the sheet 80, or removes the solvent evaporated from the coating film 82. Further, the controller 90 controls the temperature or flow rate of the air supply fan 21 so that the temperature of the sheet 80 becomes a predetermined value (for example, 60 ° C, 50 ° C, 45 ° C, or the like) of the glass transition point (about 70 ° C) of the PET film. This temperature or flow rate can also be determined in advance. Alternatively, the temperature or flow rate may be controlled to a temperature below the glass transition point by controlling the temperature or flow rate to a temperature of the sheet 80 based on, for example, the temperature detected by the temperature sensor disposed on the sheet 80 or within the furnace body 12. In this manner, the coating film 82 is dried and becomes a film in a state where the temperature of the sheet 80 is still maintained below the glass transition point, and is then carried out from the opening 16. Next, this film (coating film 82) is wound together with the sheet 80 on the roller 18 provided at the right end of the furnace body 12. Then, the film is peeled off from the sheet 80, cut into a predetermined shape, and laminated to produce MLCC.

Here, the infrared rays emitted from the infrared heater 30 when the coating film 82 is dried will be described. Fig. 3 is an explanatory view showing an example of wavelength characteristics of infrared rays radiated from the infrared heater 30. As described above, the infrared heater 30 radiates infrared rays (solid line in Fig. 3) having a peak wavelength of about 3.5 μm from the filament 31. Here, the infrared rays include infrared rays having a wavelength of 2 μm to 4 μm or infrared rays having a wavelength of less than 2 μm. Further, since the infrared heater 30 has the inner tube 32, the first outer tube 34, and the second outer tube 35 formed by the infrared ray transmissive material described above, the infrared ray having a wavelength region exceeding 4 μm is absorbed by the tubes (third) Area A of the figure. Further, the infrared heater 30 is provided with a selective reflection layer formed by the above-mentioned selective reflection material between the filament 31 and the coating film 82. 37. Therefore, in the infrared rays having a wavelength of less than 2 μm, the radiation in the direction of the coating film 82 (the direction below the first drawing) is reflected by the selective reflection layer 37 (region B in Fig. 3). The infrared ray reflected by the selective reflection layer 37 is radiated from the selective reflection layer 37 to the filament 31 side (the direction above the first drawing), but is absorbed by the infrared absorbing plate 70. Thereby, the infrared rays which reach the coating film 82 or the sheet 80 from the infrared heater 30 become a component having a wavelength of more than 4 μm or a component having a wavelength of less than 2 μm. Further, in the electromagnetic wave radiated from the filament 31 in the direction opposite to the coating film 82 (the direction in the upper direction of the first drawing), the infrared ray having a wavelength of 2 μm to 4 μm is reflected by the reflective layer 36 and then emitted toward the coating film 82 side. The ratio of the components of the infrared ray heater 30 reaching the coating film 82 or the sheet 80 having an infrared ray wavelength of 2 μm to 4 μm is higher.

Here, the correspondence between the constituent elements of the present embodiment and the constituent elements of the present invention will be clarified. The furnace body 12 of the present embodiment corresponds to the furnace body of the present invention, the filament 31 corresponds to a heating element, the infrared heater 30 corresponds to an infrared heater, the selective reflection layer 37 corresponds to a selective reflector, and the infrared absorption plate 70 corresponds to infrared absorption. body. Further, the second outer tube 35 corresponds to the tubular member and the second tube, the first outer tube 34 corresponds to the first tube, and the refrigerant flow path 79 corresponds to the refrigerant flow path. The coating film 82 corresponds to a drying target.

The drying furnace 10 of the present embodiment described above includes a selective reflection layer 37 which is disposed between the filament 31 and the coating film 82 in the furnace body 12 and reflects at least a part of the infrared rays having a wavelength of less than 2 μm and has a wavelength At least a part of the infrared rays of 2 μm to 4 μm are transmitted; and the infrared ray absorbing plate 70 is disposed in the furnace body 12 at a side opposite to the selective reflection layer 37 when viewed from the filament 31, and can absorb at least a part of infrared rays having a wavelength of less than 2 μm. . Therefore, infrared rays having a wavelength of less than 2 μm can be suppressed from reaching the coating film 82 in a straight line from the filament 31. side. Further, by having the infrared ray absorbing plate 70, the infrared ray reflected by the selective reflection layer 37 can be prevented from being reflected by the furnace body 12 or the like and reaching the coating film 82 side. Thereby, overheating of the coating film 82 can be further suppressed. In addition, when the infrared ray having a wavelength of less than 2 μm reaches the side of the coating film 82, for example, the coating film 82 or the sheet 80 is overheated, and the sheet 80 is deformed, which may adversely affect the coating film 82. In the drying furnace 10 of the present embodiment, the influence of the infrared rays from the infrared heater 30 having a wavelength of less than 2 μm on the coating film 82 can be further suppressed. Further, when the sheet 80 or the coating film 82 is overheated, for example, the amount of cold air from the air supply fan 21 required to maintain the coating film 82 at a predetermined temperature or lower or to hold the sheet 80 below the glass transition point is increased. Can be suppressed. Thereby, the energy consumption during drying can be further reduced. Further, in the drying furnace 10, the infrared rays having a wavelength of 2 μm to 4 μm radiated from the infrared heater 30 can pass through the selective reflection layer 37 to reach the side of the coating film 82, so that the coating film 82 can be dried by the infrared rays.

Further, the infrared heater 30 has a second outer tube 35 that transmits at least a part of infrared rays having a wavelength of 2 μm to 4 μm and surrounds the filament 31, and the second outer tube 35 is included in at least one of the inner peripheral surface and the outer peripheral surface. The region opposite to the infrared ray absorbing plate 70 when the filament 31 is viewed has a selective reflection layer 37. Therefore, the selective reflection layer 37 is not disposed in the furnace body 12 as a member different from the infrared heater 30, and the influence of the infrared rays from the infrared heater 30 having a wavelength of less than 2 μm on the coating film 82 can be further suppressed. .

Further, the infrared heater 30 has a first outer tube 34 that transmits at least a part of infrared rays having a wavelength of 2 μm to 4 μm and surrounds the filament 31, and a second outer tube 35 that surrounds the filament 31 and the first outer tube 34; The outer tube 34 is at least one of the inner circumferential surface and the outer circumferential surface, and when viewed from the filament 31, The region on the opposite side of the coating film 82 has a reflection layer 36 that reflects at least a part of infrared rays having a wavelength of 2 μm to 4 μm. Therefore, infrared rays having a wavelength of 2 μm to 4 μm from the electromagnetic wave radiated from the filament 31 in the opposite direction to the coating film 82 can be reflected. Thereby, the infrared rays of this wavelength can be efficiently irradiated onto the coating film 82, and the drying efficiency can be improved.

Further, the infrared ray absorbing plate 70 has a refrigerant flow path 79 through which the refrigerant can flow. Therefore, the infrared ray absorbing plate 70 can be cooled by the refrigerant, and the infrared ray absorbing plate 70 can be further suppressed from being overheated by absorbing infrared rays. Thereby, the adverse effect of the overheating of the infrared absorbing plate 70 on the coating film 82 can be further suppressed.

The present invention is not limited to the above-described embodiments, and of course, it can be implemented in various forms as long as it falls within the technical scope of the present invention.

For example, in the above embodiment, the selective reflection layer 37 is formed on the second outer tube 35 of the infrared heater 30. However, the present invention is not limited thereto, and the selective reflection layer 37 is disposed in the furnace body 12 so as to be located between the filament 31 and the coating film. 82 between. Fig. 4 is a longitudinal sectional view of a drying furnace 110 according to a modification. The drying device 110 is different from the infrared heater 130 and the infrared heater 30 except that the selective reflection layer 37, the partition wall 185 and the selective reflection layer 137, and the infrared absorption layer 170 including the infrared absorption panel 70 are replaced, and dried. The configuration of the furnace 10 is the same. Therefore, the same constituent elements as those of the drying furnace 10 among the constituent elements of the drying furnace 110 are denoted by the same reference numerals as those of the drying furnace 10, and the description thereof will be omitted. As shown in FIG. 4, the partition 185 is provided inside the furnace body 12, and horizontally partitions the space provided in the space of the infrared heater 30 and the space in which the coating film 82 is disposed in the space 12a of the furnace body 12. . The partition wall 185 transmits at least a part of infrared rays having a wavelength of 2 μm to 4 μm, and is made of the same quartz as, for example, the inner tube 32. The above-mentioned infrared ray transmissive material such as glass is formed. A selective reflection layer 137 is formed on the surface (the upper surface of Fig. 4) of the partition wall 85 on the side of the infrared heater 30. The selective reflection layer 137 is formed by the same selective reflection material as the selective reflection layer 37 described above. The infrared ray absorbing layer 170 is disposed on a surface of the inner circumferential surface of the furnace body 12 opposite to the selective reflection layer 137 (the upper side in FIG. 4) when viewed from the filament 31. The infrared ray absorbing layer 170 is formed by applying, for example, a material such as a black body paint that absorbs at least a part of infrared rays having a wavelength of less than 2 μm to the inner peripheral surface of the furnace body 12 and drying it. In the drying furnace 110, as in the above-described embodiment, the infrared ray having a wavelength of less than 2 μm can be prevented from reaching the side of the coating film 82 from the filament 31 by the selective reflection layer 137. Further, the infrared ray absorbing layer 170 can suppress the infrared rays reflected by the selective reflection layer 137 from being further reflected in the furnace body 12 or the like. Further, since the intervening wall 185 separates the space in which the infrared heater 30 is disposed and the space in which the coating film 82 is disposed, even the space in which the infrared heater 30 is disposed, the object in the space, the furnace body 12 facing the space, and the like When the wavelength is less than 2 μm of infrared rays and becomes superheated, it is difficult for the coating film 82 or the sheet 80 to become overheated. Therefore, the influence on the coating film 82 caused by the infrared rays having a wavelength of less than 2 μm from the infrared heater 30 can be more suppressed. Further, since the infrared ray absorbing layer 170 is formed on the inner peripheral surface of the furnace body 12, the independent member such as the infrared absorbing plate 70 is not disposed in the furnace body 12, and can be absorbed by the infrared absorbing body by the selective reflection layer 137. Infrared. Further, the infrared absorbing layer 170 is different from the infrared absorbing plate 70 and does not have a refrigerant flow path, but it is not always necessary to cool the infrared absorbing layer 170. This is because the space is separated by the borrowing wall 185, and even if the infrared absorbing layer 170 itself becomes overheated, the influence on the space on the side of the coating film 82 is small. In the drying furnace 110 of FIG. 4, the infrared heater 130 may also include the same as the infrared heater 30. The infrared absorbing plate 70 may be disposed in the furnace body 12 by the reflection layer 37.

In the above embodiment, the selective reflection layer 37 is formed on the outer circumferential surface of the second outer tube 35, but may be formed on the inner circumferential surface. Further, the selective reflection layer 37 is formed by directly forming a selective reflection material on the surface of the second outer tube 35, but the invention is not limited thereto. For example, a selective reflection film produced by forming a selective reflection material on a resin film as a substrate may be prepared, and then bonded to the surface of the second outer tube 35. In this case, it is preferred that the base system for selecting the reflective film is such that at least a portion of the infrared rays having a wavelength of 2 μm to 4 μm are transmitted. In the drying oven 110 of Fig. 3 described above, a selective reflection film may be used in the same manner as the selective reflection layer 137. Alternatively, instead of selectively selecting the reflective layers 37, 137, a separate member composed of the selective reflective material may be disposed between the filament 31 and the coating film 82 in the furnace body 12.

In the above embodiment, the reflective layer 36 is formed on the outer peripheral surface of the first outer tube 34, but may be formed on the inner peripheral surface. Also, those that do not include the reflective layer 36 may be employed.

In the above embodiment, the infrared ray absorbing plate 70 is disposed for each of the infrared heaters 30, but the invention is not limited thereto. For example, an infrared ray absorbing plate 70 may be disposed to cover the opposite side of the plurality of infrared heaters 30 from the selective reflection layer 37. Further, the drying furnace 10 may include an infrared absorbing layer 170 instead of the drying furnace 110 of the infrared absorbing plate 70.

In the above-described embodiment, the inner tube 32, the first outer tube 34, and the second outer tube 35 are formed of quartz glass that absorbs infrared rays having a wavelength of more than 4 μm and transmits infrared rays of 4 μm or less. However, the wavelength is 2 μm. At least a part of the infrared rays of 4 μm can be transmitted. For example, the inner tube 32, the first tube Any one or more of the outer tube 34 and the second outer tube 35 are made of infrared rays having an absorption wavelength of more than 3.5 μm and infrared rays having a wavelength of 3.5 μm or less. Similarly, the selective reflection layer 37 is formed by transmitting at least a part of infrared rays having a wavelength of 2 μm to 4 μm, but at least a part of infrared rays having a wavelength of 2 μm to 3.5 μm may be used. The infrared ray having a wavelength of 3.5 μm or less is excellent in the performance of hydrogen bonding in molecules such as water or solvent, so the inner tube 32, the first outer tube 34, the second outer tube 35, and the selective reflection layer 37 are used. The infrared rays are transmitted, and the coating film 82 can be dried more efficiently.

In the above-described embodiment, the filament 31 is an electromagnetic wave having a radiation peak wavelength of about 3.5 μm. However, the filament 31 is not limited to a region where the peak wavelength is in the range of 2 μm to 4 μm, and the peak wavelength may be in a region of less than 2 μm or more than 4 μm. In this case, the infrared rays having a wavelength of less than 2 μm or the infrared rays having a wavelength of more than 4 μm are prevented from reaching the coating film 82 by the inner tube 32, the first outer tube 34, the second outer tube 35, and the selective reflection layer 37. In other words, even when the peak wavelength of the electromagnetic wave radiated from the filament 31 is not in the region of 2 μm to 4 μm, the inner tube 32, the first outer tube 34, the second outer tube 35, and the selective reflection layer 37 can be used to reach The peak wavelength of the electromagnetic wave of the coating film 82 becomes 2 μm to 4 μm. However, in order to improve the drying efficiency, it is preferable that the peak wavelength of the electromagnetic wave radiated from the filament 31 is in the range of 2 μm to 4 μm.

In the above embodiment, the coating film 82 is used as a film for MLCC, but the invention is not limited thereto. For example, it can also be used as a film for LTCC (Low Temperature Baking Ceramic) or other green sheets. Alternatively, the coating film 82 may be used as a coating film for a battery electrode such as a lithium ion secondary battery. In this case, the coating film 82 may also be made of an electrode material (positive electrode active material or negative electrode active material), a binder, An electrode material paste which is kneaded together with a conductive material and a solvent is applied to the sheet 80. In the case where the coating film 82 is a coating film for an electrode for a battery, the sheet 80 may be a metal sheet such as aluminum or copper. Further, depending on the material of the coating film 82 or the sheet 80, the temperature of the air blown from the air supply fan 21 may be appropriately changed, and the air blower may be used, for example, in the range of 40 to 400 °C.

The present patent application is based on Japanese Patent Application No. 2013-083032, filed on Jan.

[Industrial Applicability]

The present invention can be utilized in industries in which drying of a drying target such as a coating film is required, for example, a ceramic industry for producing MLCC or LTCC, a battery industry for producing an electrode coating film for a lithium ion secondary battery, and the like.

10‧‧‧ drying oven

12‧‧‧ furnace body

12a‧‧‧ Space

13‧‧‧ front end

14‧‧‧ rear end face

15‧‧‧ openings

16‧‧‧ openings

17‧‧‧ Roll

18‧‧‧ Roll

19‧‧‧Transportation

20‧‧‧ gas supply

21‧‧‧Air supply fan

22‧‧‧ tube structure

23‧‧‧ gas supply port

25‧‧‧Exhaust device

26‧‧‧Exhaust fan

27‧‧‧ tube structure

28‧‧‧Exhaust port

30‧‧‧Infrared heater

31‧‧‧ filament

32‧‧‧Inside

33‧‧‧ heater body

34‧‧‧1st outer tube

35‧‧‧2nd outer tube

36‧‧‧reflective layer

37‧‧‧Selecting the reflective layer

39‧‧‧Refrigerant flow path

70‧‧‧Infrared absorption board

79‧‧‧Refrigerant flow path

80‧‧‧Sheet

82‧‧·coating film

90‧‧‧ Controller

Claims (6)

A drying furnace comprising: a furnace body for drying a drying object; an infrared heater disposed in the furnace body and having a heating element for emitting electromagnetic waves containing infrared rays; and selecting a reflector body disposed in the furnace body Between the heating element and the object to be dried, at least a part of infrared rays having a wavelength of less than 2 μm are reflected, and at least a part of infrared rays having a wavelength of 2 μm to 4 μm are transmitted; and an infrared absorber is disposed in the furnace body. When the heating element is observed, it is opposite to the selective reflection system, and at least a part of infrared rays having a wavelength of less than 2 μm can be absorbed. The drying furnace according to claim 1, wherein the infrared heater has a tubular member that transmits at least a part of infrared rays having a wavelength of 2 μm to 4 μm and surrounds the heat generating body; the tubular member is inner circumferential surface and outer circumferential surface At least one of the selected reflectors is provided in a region on the side opposite to the infrared absorbing system when viewed from the heat generating body. The drying furnace according to claim 2, wherein the infrared heater has a first tube that transmits at least a part of infrared rays having a wavelength of 2 μm to 4 μm and surrounds the heating element; and the second tube surrounds the heat generation And a tubular member of the first tube; the first tube has at least one of an inner circumferential surface and an outer circumferential surface having a reflection wavelength of 2 μm in a region on the opposite side of the drying target when viewed from the heating element. A reflective layer of at least a portion of the infrared rays of 4 μm. The drying furnace according to any one of claims 1 to 3, further comprising a partition wall in which a space in which the infrared heater is disposed and a space in which the drying object is disposed are arranged and the wavelength is At least a portion of the infrared rays of 2 μm to 4 μm are transmitted; the partition wall has the selective reflector. A drying oven according to the fourth aspect of the invention, wherein the furnace system has the infrared absorber on an inner circumferential surface. The drying furnace according to any one of claims 1 to 3, wherein the infrared absorbing system has a refrigerant flow path through which a refrigerant can flow.