Drying device

Abstract

A drying device according to the present invention comprises: a first detection unit (5) that detects infrared rays, which have a wavelength outside the infrared absorption wavelength range, from vapor generated from a heated object (4); and a second detection unit (6) that detects infrared rays, which have a wavelength in only the infrared absorption wavelength range, from the vapor generated from the heated object. The drying device can carry out drying while ascertaining, for example, a transition in the amount of decrease (i.e., the evaporation amount) of a solvent in the object to be heated from an initial stage of drying to a final stage of drying.

Description

drying equipment

[0001] The present disclosure relates to a drying device that dries an object to be heated while grasping the temperature and amount of steam of the object to be heated.

[0002] In the manufacturing process of electronic devices, batteries, ceramic products, etc., there is a process of applying a coating film to a substrate and drying it. In a general drying process, it is required to dry the coating film as quickly as possible to improve productivity.

[0003] However, if drying is carried out too quickly, especially during the drying period from the initial stage to the final stage, problems such as segregation of the components in the coating film can occur, reducing the adhesion between the substrate and the coating film, and causing wrinkles or cracks in the dried coating film. Therefore, it is important to balance productivity and quality by monitoring the amount of vapor from the coating film and the drying state with a measuring instrument, etc., and drying as quickly as possible without affecting quality.

[0004] Patent Document 1 discloses a drying device that dries an object to be heated while measuring the state of the object to be heated using a measuring device.

[0005] FIG. 6 is a schematic diagram of the drying device described in Patent Document 1.

[0006] In the drying device 101, the object 102 to be heated is transported from the entrance to the exit along guide rolls 106 inside the drying device 101. The object 102 to be heated is dried using a drying nozzle 103 while the temperature of the object 102 is measured using multiple temperature measuring devices 104 installed at the top of the drying device 101. When most of the solvent in the object 102 to be heated has evaporated and the drying reaches the end, the temperature of the object 102 to be heated rises. The drying device detects the temperature rise using the temperature measuring device 104 and controls the height of the drying nozzle 103 using a control unit 105 to adjust the heating intensity.

[0007] Patent No. 5924570

[0008] The drying device of Patent Document 1 only measures the temperature of the object 102 to be heated, and can only determine the final stage of drying when the temperature of the object 102 rises. This drying device cannot quantitatively determine how quickly the object 102 is drying from the initial stage to the final stage of drying, which affects quality. Therefore, during the drying period from the initial stage to the final stage of drying, it is difficult to increase the drying speed due to concerns about a decrease in quality, and productivity decreases.

[0009] The present disclosure aims to provide a drying device that can perform a drying process that balances productivity and quality by determining the temperature of the object to be heated and the amount of steam generated from the object to be heated, thereby enabling the object to be dried while deriving the trend in the amount of solvent reduction (i.e., evaporation amount) in the object to be heated during the drying period.

[0010] According to one aspect of the present disclosure, there is provided a drying device that dries an object to be heated while grasping the temperature of the object to be heated and the amount of steam generated from the object to be heated, and the drying device comprises: a heating means that heats the object to be heated within a drying chamber that stores the object to be heated; a first detection unit that is arranged opposite the object to be heated within the drying chamber and detects infrared rays with wavelengths outside the infrared absorption wavelength range of the steam generated from the object to be heated; a second detection unit that is arranged opposite the object to be heated within the drying chamber and detects infrared rays with wavelengths only within the infrared absorption wavelength range of the steam generated from the object to be heated; a calculation unit that calculates the temperature of the object to be heated and the amount of steam generated from the object to be heated from the values ​​of the first detection unit and the second detection unit; and a control unit that controls the heating means based on the calculation results of the calculation unit.

[0011] As described above, the drying apparatus according to the above aspect of the present disclosure includes a first detector that detects infrared rays having wavelengths outside the infrared absorption wavelength range of the vapor generated from the object to be heated, and a second detector that detects infrared rays having wavelengths only within the infrared absorption wavelength range of the vapor generated from the object to be heated. Such a drying apparatus can dry the object to be heated while monitoring the progress of the reduction in the amount of solvent (i.e., the evaporation amount) in the object to be heated, for example, from the initial stage to the final stage of drying, thereby achieving both high productivity and high quality.

[0012] Schematic configuration diagram of a drying device according to a first embodiment of the present disclosure. Control configuration diagram of a drying device according to a first embodiment of the present disclosure. Illustrative diagram of infrared detection wavelength ranges of a first detection unit and a second detection unit when the steam is water. Illustrative diagram of a drying profile from the initial stage to the final stage of drying of an object to be heated. Illustrative configuration diagram of a drying device according to a second embodiment of the present disclosure. Illustrative configuration diagram of a conventional drying device.

[0013] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0014] 1 and 2 are a schematic configuration diagram and a control configuration diagram of a drying device 1 according to a first embodiment of the present disclosure.

[0015] The drying device 1 is disposed in a drying chamber 2 and heats and dries an object 4 to be heated. The drying device 1 includes a heating means (or heating device) 3, a first detection unit 5, a second detection unit 6, and a control unit 8. The first detection unit 5 and the second detection unit 6 each detect infrared rays in different wavelength regions emitted from the object 4 to be heated. As will be described later, the calculation unit 7 calculates the temperature of the object 4 to be heated and the amount of steam generated from the object 4 to be heated. The control unit 8 determines the temperature of the object 4 to be heated and the amount of steam in the object 4 based on the calculation results of the calculation unit 7 and controls the heating means 3.

[0016] The heating means 3 is, for example, a hot air nozzle, a heater, or a microwave oscillator.

[0017] The first detector 5 is disposed in the drying chamber 2 so as to be able to face the object 4 to be heated, and detects infrared rays having wavelengths outside the infrared absorption wavelength range of the steam generated from the object 4 to be heated.

[0018] The second detector 6 is disposed in the drying chamber 2 so as to be able to face the object 4 to be heated, and detects infrared rays having a wavelength in the infrared absorption wavelength range of the steam generated from the object 4 to be heated.

[0019] Here, the first detection unit 5 and the second detection unit 6 being arranged so as to be able to face the object to be heated 4 within the drying chamber 2 does not necessarily mean that they are arranged to face each other perpendicularly to the conveying direction of the object to be heated 4, but also includes that they are arranged to face each other diagonally to the conveying direction, as long as they can detect the area near the surface of the object to be heated 4.

[0020] As an example of infrared detection by the first detection unit 5 and the second detection unit 6, a case where the steam generated from the heated object 4 is water will be described. Generally, the heated object 4 is heated to a temperature of several tens of degrees Celsius to approximately 100°C during the drying process to dry. As shown in FIG. 3 , infrared rays emitted from a radiator follow Planck's law of radiation. Under Planck's law, the wavelength and spectrum of spectral radiant energy are determined by the temperature of the radiator (FIG. 3 shows the radiator at 100°C). The infrared energy at each wavelength of the infrared rays radiated from the heated object 4 is determined by the product of the spectrum and the emissivity of the heated object 4 at each wavelength. When the temperature of the radiator is lower than 100°C, the peak of the spectrum shifts to the longer wavelength side. When the temperature of the radiator (heated object 4) is between several tens of degrees Celsius and 100°C, the wavelength of the peak infrared energy of the radiated infrared rays is approximately 8 to 10 μm. When the steam generated from the heated object 4 is water, the infrared absorption wavelength of the steam is in the range of 2.5 to 2.9 μm or 5.0 to 7.7 μm. Setting the infrared detection wavelength range to a wavelength range with high infrared energy improves measurement accuracy. From the perspective of improving measurement accuracy, the wavelength range of the infrared detected by the second detection unit 6 is preferably set to 5.0 to 7.7 μm. Furthermore, since the wavelength range of the infrared detected by the first detection unit 5 is outside the infrared absorption wavelength range of the steam, it is considered to be set to approximately 3.0 to 5.0 μm or approximately 8.0 to 12.0 μm. From the perspective of the temperature of the radiator (heated object 4) (e.g., from several tens of degrees Celsius to approximately 100°C), the wavelength range of the infrared detected is preferably set to approximately 8.0 to 12.0 μm, which improves measurement accuracy. Similarly, even if the steam generated from the heated object 4 contains a component other than water, the wavelength range of the infrared rays detected by the first detection unit 5 and the second detection unit 6 is set to match the infrared absorption wavelength range of the steam component.

[0021] In this embodiment, in the infrared detection wavelength ranges of the first detection unit 5 and the second detection unit 6, a non-detection region ND is provided in a portion of the wavelength range outside the infrared absorption wavelength range adjacent to the infrared absorption wavelength range, where both the first detection unit 5 and the second detection unit 6 do not detect. This prevents the first detection unit 5 and the second detection unit 6 from erroneously detecting infrared rays of wavelengths outside the ranges they are intended to detect. In other words, the non-detection region ND is provided between the infrared detection wavelength range of the second detection unit 6 and the infrared detection wavelength range of the first detection unit 5. This non-detection region ND prevents the first detection unit 5 and the second detection unit 6 from erroneously detecting infrared rays. The width of the non-detection region ND is desirably set to 0.1 μm or more and 15 μm or less, taking into account the wavelength control resolution of a means for transmitting or blocking infrared rays in a specific wavelength range, such as a bandpass filter or metamaterial described below, and the wavelength range of the infrared spectrum emitted from the heated object 4.

[0022] As an example, when the vapor is water, the infrared detection wavelength range of the first detection unit 5 is 8.0 to 12.0 μm, the infrared detection wavelength range of the second detection unit 6 is 5.0 to 7.7 μm, and the width of the non-detection region ND is 0.3 μm.

[0023] As an example of a means by which the first detection unit 5 and the second detection unit 6 each detect only a specific infrared wavelength range, a bandpass filter that transmits only infrared rays in a specific wavelength range and blocks (reflects) infrared rays in other wavelength ranges can be installed within the field of view of the infrared detector, thereby making it possible to detect only infrared rays in a specific wavelength range.

[0024] A method for calculating the amount of steam generated from the object to be heated 4 using the infrared rays detected by the first detection unit 5 and the second detection unit 6 will be described below.

[0025] Before the object 4 is dried, a thermocouple is used to directly measure the temperature of the object 4, as in a typical infrared sensor. The emissivity of the object 4 is set based on the outputs of the first and second detection units 5 and 6. When the object 4 is placed in the drying chamber 2, it is heated by the heating means 3 located above the drying chamber 2, causing steam to be generated from the object 4. The first and second detection units 5 and 6, located above the object 4 and facing the object 4, respectively, detect infrared rays of different wavelengths emitted from the object 4. The first detection unit 5 detects infrared rays of wavelengths that are not absorbed by the steam generated from the object 4, thereby enabling accurate measurement of the temperature of the object 4 without the problem of reduced infrared detection accuracy due to steam, which is a problem with typical infrared thermometers. Furthermore, the calculation unit 7 can derive an infrared spectrum from the temperature of the object 4 measured by the first detection unit 5 and Planck's radiation law. Based on the infrared spectrum, the calculation unit 7 can estimate the infrared energy radiated from the object 4 in the infrared detection wavelength range of the second detection unit 6. Simultaneously with the measurement by the first detector 5, the second detector 6 measures the infrared energy radiated from the object 4 and attenuated by the steam generated from the object 4. The degree of attenuation of infrared light by steam is expressed by the Lambert-Beer law as follows: １０ (I １ / I ０ ) = abc (where I ０ : infrared energy radiated from the object to be heated 4, I １ : infrared energy attenuated by vapor, a: absorption coefficient [m ２ / g], b: distance [m], c: concentration [g / m ３ ]). The absorption coefficient of the vapor substance, which is a literature value or has been previously determined by experiment, the distance from each of the first detection unit 5 and the second detection unit 6 to the heated object 4, and the spot diameter of the detection range of each of the first detection unit 5 and the second detection unit 6 are input into the calculation unit 7. Then, the calculation unit 7 can calculate the amount of vapor generated from the heated object 4 from the ratio between the infrared energy estimated from the temperature measured by the first detection unit 5 and the infrared energy measured by the second detection unit 6.

[0026] 4 is a graph of a drying profile showing the change over time in the amount of steam generated from the object 4 and the change in the amount of solvent in the object 4. Since the amount of steam generated from the object 4 is proportional to the amount of solvent lost (i.e., the amount of evaporation) in the object 4, the integral of the total amount of steam in the graph of FIG. 4 corresponds to the initial amount of solvent in the object 4. The amount of solvent lost (i.e., the amount of evaporation) in the object 4 in each drying section can be calculated from the ratio of the integral of the total amount of steam to the integral of the amount of steam in each drying section. Therefore, although it depends on the object 4, a drying profile can be implemented that improves productivity as much as possible while maintaining quality, such as by drying slowly in a drying section that affects quality (e.g., the middle drying section D2 in the graph of FIG. 4) and drying quickly in the other drying sections D1 and D3.

[0027] In addition to using the bandpass filters described above, metamaterial structures can be used as a means for the first detection unit 5 and the second detection unit 6 to detect only a specific infrared wavelength range. In recent years, active research has been conducted on metamaterials, which microfabricate the surface structure of an infrared detection unit to control the infrared absorption spectrum of the infrared detection unit. Examples of structures used to control absorption wavelengths include a structure in which metal holes or protrusions are periodically arranged in a two-dimensional plane on two thin film layers of metal and dielectric, or a layered structure in which two types of dielectrics with different refractive indices are alternately stacked on a metal layer. In this way, by designing the microstructure of the surface of the infrared detection unit, it is possible to detect infrared rays with a wavelength distribution that has a narrow band peak at any wavelength.

[0028] As described above, the drying device 1 according to the first embodiment of the present disclosure includes a first detector 5 that detects infrared rays in an infrared wavelength range that is not absorbed by the steam generated from the object 4 to be heated, and a second detector 6 that detects infrared rays in an infrared wavelength range that is absorbed by the steam. This configuration allows the object 4 to be dried while monitoring the temperature of the object 4 and the amount of steam generated from the object 4. Therefore, for example, the object 4 can be dried while monitoring the amount of steam generated from the object 4 from the beginning to the end of drying, which affects product quality. In other words, the object 4 can be dried while monitoring the progress of the reduction in the amount of solvent (i.e., the evaporation amount) in the object 4 from the beginning to the end of drying, thereby achieving both high productivity and high quality.

[0029] FIG. 5 is a schematic diagram of a drying apparatus 1 according to a second embodiment of the present disclosure. Within a drying chamber 2, multiple drying units 10, each consisting of a heating means 3, a first detector 5, and a second detector 6, are arranged along the conveying direction A of the objects 4. A conveying unit 9, such as a belt conveyor, sequentially conveys the objects 4 to the drying units 10 within the drying chamber 2. A calculation unit 7 calculates the temperature and amount of steam of the objects 4 heated by the heating means 3 of each drying unit 10 based on the detection data of the first detector 5 and the second detector 6 of each drying unit 10. The detection data of each detector 5 and 6 is extracted over time in accordance with the conveying speed of the objects 4, and the calculation unit 7 calculates the amount of steam generated in each drying unit 10 for each individual object 4. This allows the calculation unit 7 to grasp the transition in the amount of steam generated from the objects 4 from the entrance to the exit of the drying apparatus 1, and to derive a drying profile from the initial stage of drying to the final stage of drying. Therefore, based on the calculation results of the calculation unit 7 for the drying unit 10 on the entrance side of the conveying direction A and a predetermined drying profile stored in advance, the control unit 8 can control the heating by the heating means 3 of the drying unit 10 on the exit side of the conveying direction A adjacent to the drying unit 10 on the entrance side of the conveying direction A so as to reduce the difference between the calculation results and the predetermined drying profile.

[0030] As described above, according to the drying device 1 of the second embodiment of the present disclosure, each drying unit 10 is provided with a first detector 5 that detects infrared rays in an infrared wavelength range that is not absorbed by the steam generated from the object 4 to be heated, and a second detector 6 that detects infrared rays in an infrared wavelength range that is absorbed by the steam. This configuration allows each drying unit 10 to dry the object 4 while grasping the temperature of the object 4 and the amount of steam generated from the object 4. Therefore, for example, the object 4 can be dried while grasping the amount of steam generated from the object 4 from the beginning to the end of drying, which affects product quality. In other words, each drying unit 10 can dry the object 4 while grasping the progress of the reduction in the amount of solvent (i.e., the evaporation amount) in the object 4 from the beginning to the end of drying, thereby achieving both high productivity and high quality.

[0031] It should be noted that any of the various embodiments or modifications described above can be appropriately combined to achieve the effects of each. In addition, combinations of embodiments, combinations of examples, or combinations of embodiments and examples are possible, and combinations of features from different embodiments or examples are also possible.

[0032] (Additional Notes) The above description of the embodiments discloses the following techniques.

[0033] (Technology 1) A drying device that dries an object to be heated while keeping track of the temperature of the object to be heated and the amount of steam generated from the object to be heated, comprising: a heating means that heats the object to be heated within a drying chamber that stores the object to be heated; a first detection unit that is arranged in the drying chamber so as to be able to face the object to be heated and that detects infrared rays with wavelengths outside the infrared absorption wavelength range of the steam generated from the object to be heated; a second detection unit that is arranged in the drying chamber so as to be able to face the object to be heated and that detects infrared rays with wavelengths only within the infrared absorption wavelength range of the steam generated from the object to be heated; a calculation unit that calculates the temperature of the object to be heated and the amount of steam generated from the object to be heated from the value of the first detection unit and the value of the second detection unit; and a control unit that controls the heating means based on the calculation result of the calculation unit.

[0034] (Technology 2) The drying device according to Technology 1, wherein a surface of each of the first detection unit and the second detection unit has a metamaterial structure.

[0035] (Technology 3) The drying device according to Technology 1 or 2, wherein in the infrared detection wavelength range of the first detection unit and the second detection unit, a non-detection region that is not detected by both the first detection unit and the second detection unit is included in a part of the wavelength region outside the infrared absorption wavelength region adjacent to the infrared absorption wavelength region.

[0036] (Technology 4) The drying device according to Technology 3, wherein the vapor is water, the infrared detection wavelength region of the first detection unit is 8.0 to 12.0 μm, the infrared detection wavelength region of the second detection unit is 5.0 to 7.7 μm, and a width of the non-detection region is 0.3 μm.

[0037] (Technology 5) A drying device according to any one of Technologies 1 to 4, wherein a plurality of drying units, each of which is composed of the heating means, the first detection unit, and the second detection unit of the drying device, are arranged in the drying chamber along the conveying direction of the object to be heated, and the calculation unit of the drying device calculates the temperature of the object to be heated in each drying unit and the amount of steam generated from the object to be heated from the values ​​of the first detection unit and the second detection unit of each drying unit, and the control unit of the drying device controls the heating means of the drying unit on the outlet side of the conveying direction adjacent to the drying unit on the entrance side of the conveying direction based on the calculation result of the calculation unit for the drying unit on the entrance side of the conveying direction and a drying profile.

[0038] The heating device includes a first detector that detects infrared rays having wavelengths outside the infrared absorption wavelength range of the vapor generated from the object to be heated, and a second detector that detects infrared rays having wavelengths only within the infrared absorption wavelength range of the vapor generated from the object to be heated. By configuring the device in this way, it is possible to dry the object while monitoring the progress of the reduction in the amount of solvent (i.e., the evaporation amount) from the initial stage of drying to the final stage of drying, thereby achieving both high productivity and high quality.

[0039] The drying device according to the above aspect of the present disclosure can dry an object while monitoring the temperature and steam volume of the object from the initial stage to the final stage of drying, thereby achieving both productivity and quality. Therefore, the above aspect of the present disclosure can be applied to heat treatment devices such as drying furnaces in the manufacturing process of industrial products or home appliances or electronic components.

[0040] REFERENCE SIGNS LIST 1 Drying device 2 Drying chamber 3 Heating means 4 Object to be heated 5 First detection section 6 Second detection section 7 Calculation section 8 Control section 9 Conveying section 10 Drying unit 101 Drying device 102 Object to be heated 103 Drying nozzle 104 Temperature measuring device 105 Control section 106 Guide roll ND Non-detection area

Claims

1. A drying device that dries a heated object while keeping track of the temperature of the heated object and the amount of steam generated from the heated object, comprising: a heating means for heating the heated object within a drying chamber that stores the heated object; a first detection unit that is arranged in the drying chamber so as to be able to face the heated object and detects infrared rays having a wavelength outside the infrared absorption wavelength range of the steam generated from the heated object; a second detection unit that is arranged in the drying chamber so as to be able to face the heated object and detects infrared rays having a wavelength only within the infrared absorption wavelength range of the steam generated from the heated object; a calculation unit that calculates the temperature of the heated object and the amount of steam generated from the heated object from the value of the first detection unit and the value of the second detection unit; and a control unit that controls the heating means based on the calculation result of the calculation unit.

2. The drying device according to claim 1, wherein a surface of each of the first detection portion and the second detection portion has a metamaterial structure.

3. A drying device as described in claim 1, wherein in the infrared detection wavelength range of the first detection unit and the second detection unit, a portion of the wavelength range outside the infrared absorption wavelength range adjacent to the infrared absorption wavelength range has a non-detection region that is not detected by both the first detection unit and the second detection unit.

4. The drying device according to claim 3, wherein the steam is water, the infrared detection wavelength range of the first detection unit is 8.0 to 12.0 μm, the infrared detection wavelength range of the second detection unit is 5.0 to 7.7 μm, and the width of the non-detection area is 0.3 μm.

5. The drying device described in claim 1, wherein a plurality of drying units each consisting of the heating means, the first detection unit, and the second detection unit of the drying device are arranged in the drying chamber along the transport direction of the heated object, and the calculation unit of the drying device calculates the temperature of the heated object in each drying unit and the amount of steam generated from the heated object from the respective values ​​of the first detection unit and the second detection unit of each drying unit, and the control unit of the drying device controls the heating means of the drying unit on the exit side of the transport direction adjacent to the drying unit on the entrance side of the transport direction based on the calculation result of the calculation unit for the drying unit on the entrance side of the transport direction and a drying profile.

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