Hot air type dryer

Abstract

To provide a hot air type dryer excellent in environment friendliness, energy efficiency and safety, capable of adopting a heater heating system and suppressing heating energy required for obtaining a proper temperature and amount of heating hot air generated by heater heating due to its configuration of circulating and mixing exhaust hot air.SOLUTION: The hot air type dryer comprises a hot air generator 5 configured to control mixed hot air at an intended temperature, the mixed hot air being prepared by mixing heater heated hot air generated by heating sucked air by a heater 6 with exhaust hot air circulated from a drying chamber 3, to deliver it to a hot air delivery unit 4 present in the drying chamber 3.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a drying device provided in a coating device configured to transport a film-shaped object to be coated (substrate) to a nozzle section that ejects a coating liquid from, for example, a slit-shaped tip discharge hole, and to a hot air drying device in which the film-shaped substrate after coating is transported and passed through a drying chamber section configured to heat the substrate with hot air, thereby drying the coating film on the substrate surface. [Background technology]

[0002] The hot air drying device installed in the coating device transports and passes through a film-like substrate having a surface coated with a coating liquid by the coating device and discharged from the coating device, and dries the coating film on the surface of the substrate using hot air and heat from a heater section that is further installed.

[0003] Such a hot air drying device is configured to have a long drying chamber length, with multiple main body sections (divided drying chamber forming sections) arranged side by side on the left and right, which transport and pass a film-like substrate via transport inlet and outlet sections provided on the left and right. Within each drying chamber forming section that constitutes this drying chamber, for example, multiple support rollers are arranged side by side in the horizontal direction, and the film-like substrate is passed over these support rollers. While the film-like substrate is taken up and transported horizontally, the coated surface (coating film) of the substrate is dried using hot air from a hot air blowing section and heat from a heater section that is further provided, or hot air blowing sections are provided above and below, and the coating film is dried using a floating drying method while the substrate is transported and passed without contact.

[0004] In addition, such a hot air type drying device is configured to include a hot air generating section that sends hot air generated by heating to a desired temperature to the hot air delivery section provided in such a drying chamber.

[0005] If this hot air generating section were simply configured to heat the air (outside air) drawn in by the air blowing section (draw-in fan) in the heater section to generate hot air, and then blow this air out to the hot air blowing section through a duct, it would require a large amount of heating energy and be inefficient, so in this case all or part of the exhaust hot air from the drying chamber is branched off from the exhaust pipe and circulated, and this is reheated or mixed with the drawn-in outside air and heated to generate hot air of the desired temperature, which is then sent again to the hot air blowing section of the drying chamber.

[0006] In addition, depending on the coating liquid applied to the substrate, there is a risk of generating dangerous gases such as flammable gases during drying, and therefore the exhaust hot air may contain such dangerous gases in dangerous concentrations or above. Therefore, it is not preferable to use a heater section to heat the exhaust hot air exhausted from the drying chamber or a mixture of this exhaust hot air and outside air.

[0007] For this reason, conventionally, the heat source of the hot air generating section that heats the circulated exhaust hot air has been a steam-type heat exchanger in which steam heated by a boiler is passed through a heat exchange tube, and the exhaust hot air is blown through this tube to heat it by heat exchange.

[0008] However, in recent years, there has been an increasing demand to reduce CO2 emissions in order to prevent global warming, and there is a growing demand to change the configuration of the hot air in the drying equipment from heat exchange heating using a steam heat exchanger that requires boiler heating to heater heating using an electric heater unit.

[0009] Therefore, the applicant engaged in research and development of a drying device that would solve these problems and also meet these demands, and the present inventor created the present invention. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] JP 2020-118363 A [Patent Document 2] JP 2022-163891 A Summary of the Invention [Problem to be solved by the invention]

[0011] The present invention solves these problems and meets these demands. The hot air of the desired temperature that is sent to the hot air exhaust section of the drying chamber is heated and generated by an electric heater, thereby responding to the demand for CO2 reduction and realizing an environmentally friendly drying device. In addition, since the hot air of the desired temperature is generated by mixing the drawn-in air heated by a heater with the circulated exhaust hot air, energy efficiency is improved and electricity is saved, making it more environmentally friendly. Moreover, even in the case of a drying device that dries a coating film that may produce dangerous gases such as flammable gases during drying, the exhaust hot air contained therein is not heated, but the air taken in (outside air) is heated by a heater, so this is a hot air type drying device with a hot air generating section that is also safe. [Means for solving the problem]

[0012] The gist of the present invention will now be described with reference to the accompanying drawings.

[0013] The present invention relates to a hot air drying device in which a film-like substrate 2, which has been coated with a coating liquid by a coating device 1 and is delivered from the coating device 1, is transported and passed through a drying chamber 3, and a hot air delivery section 4 is provided in the drying chamber 3 for delivering hot air for drying the coating liquid applied to the substrate 2. The hot air generation section 5 is provided for generating hot air to be delivered to the hot air delivery section 4 of the drying chamber 3 and delivering the hot air to the hot air delivery section 4. The hot air generation section 5 for delivering hot air to at least the hot air delivery section 4 on the upstream side of the transport of the substrate 2 in the drying chamber 3 is provided with a heater heating generation section 7 for heating drawn-in air with a heater section 6 and generating hot air, This hot air type drying device is characterized in that it is configured to include a mixing section 8 that mixes heater-heated hot air generated in a heater heating generation section 7 with exhaust hot air exhausted from the drying chamber section 3 and delivers the mixed hot air, and an air blowing section 9, and the mixed hot air drawn in and mixed by the air blowing section 9 is delivered to the hot air delivery section 4 of the drying chamber section 3, and is provided with a hot air temperature control section C that controls the heating degree of the heater section 6 or the air blowing degree of the air blowing section 9 in accordance with the mixing ratio of the heater-heated hot air and the exhaust hot air so that the temperature of the mixed hot air becomes a desired temperature.

[0014] The hot air generating section 5 draws in and mixes the heater-heated hot air generated by the heater heating generating section 7 and the exhaust hot air exhausted from the drying chamber section 3 by using negative air pressure, and the air blowing section 9 is provided at a position where the drawn-in and mixed mixed hot air is blown out to the hot air blowing section 4 of the drying chamber section 3, so that the exhaust hot air is not heated by the heater section 6 of the heater heating generating section 7. This is characterized in that the hot air drying device according to the present invention is characterized in that the air blowing section 9 is provided at a position where the drawn-in and mixed mixed hot air is blown out to the hot air blowing section 4 of the drying chamber section 3, so that the exhaust hot air is not heated by the heater section 6 of the heater heating generating section 7.

[0015] The drying device according to claim 1 is further characterized in that a temperature sensor 10 is provided for detecting the temperature of the mixed hot air discharged to the hot air discharge section 4 of the drying chamber section 3, and the hot air temperature control section C is configured to control the heating intensity of the heater section 6 based on the temperature detected by this temperature sensor 10.

[0016] The drying chamber section 3 is configured such that a plurality of drying chamber forming sections 11 are arranged in parallel in the transport direction of the base material 2, and the downstream hot air generating section 12 that generates hot air and sends it to the hot air sending section 4 provided in the drying chamber forming section 11 on the downstream side of the transport is not the hot air generating section 5, but is configured to include a circulating mixing heater heating generating section 13 that heats a mixed hot air, which is a mixture of the drawn-in air and the exhaust hot air exhausted from the drying chamber section 3, in the heater section 6 to generate heater-heated mixed hot air, and the air blowing section 9, and the heater-heated mixed hot air generated in the circulating mixing heater heating generating section 13 is configured to be sent to the hot air sending section 4 provided in the drying chamber forming section 11 on the downstream side of the transport.

[0017] The present invention relates to a hot air drying device as described in claim 4, characterized in that it is configured to include a gas sensor 14 for detecting the degree to which the exhaust hot air contains flammable gas. Effect of the Invention

[0018] Since the present invention is configured as described above, the hot air of the desired temperature that is sent to the hot air exhaust section of the drying chamber is heated and generated by an electric heater section, thereby responding to the demand for CO2 reduction and realizing an environmentally friendly drying device. In addition, since the hot air of the desired temperature is generated by mixing the drawn-in air heated by a heater with the circulated exhaust hot air, energy efficiency is improved and electricity is saved, making it more environmentally friendly. Moreover, even if the present invention is a drying device for drying a coating film that may produce dangerous gases such as flammable gases during drying, the exhaust hot air contained therein is not heated but the air taken in (outside air) is heated by a heater, making it a hot air type drying device with a hot air generating section that is also safe. [Brief description of the drawings]

[0019] [Figure 1] FIG. 2 is a side view for explaining the schematic configuration of the present embodiment. [Diagram 2]1 is an explanatory diagram of a hot air generating section that generates hot air to be sent to a hot air delivery section of a drying chamber forming section on the upstream side of the conveying direction of the drying chamber in this embodiment. FIG. [Diagram 3] 1 is an explanatory diagram of a downstream hot air generating section that generates hot air to be sent to the hot air blowing section of the drying chamber forming section on the downstream side of the conveyance of the drying chamber section in this embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] A preferred embodiment of the present invention will be briefly described below with reference to the drawings to illustrate the operation of the present invention.

[0021] For example, a film-like substrate 2 that has been coated by a coating device 1 is conveyed through a drying chamber 3, whereby the coating film formed on the surface is dried.

[0022] That is, for example, when the substrate 2 with a coating on its upper surface is picked up and transported through the drying chamber 3, the coating film on the upper surface is dried by the heat of the hot air blown out from the hot air blowing section 4 provided in the drying chamber 3.

[0023] The hot air sent from the hot air delivery section 4 into the drying chamber 3 is heated and generated in the hot air generation section 5, and is sent into the drying chamber 3 via the hot air delivery section 4 by the air sending section 9 (blower device or fan device).

[0024] In the present invention, outside air is drawn into the heater heating generation section 7 of the hot air generation section 5 by an air blower 9 such as an intake fan, this outside air is heater-heated by an electric heater section 6 of the heater heating generation section 7, and this heater-heated hot air and the exhaust hot air exhausted from the drying chamber section 3 (all or part of the exhaust hot air) are drawn into the mixing section 8 at a predetermined mixing ratio via the valve 21 and merged and mixed, and this mixed hot air is then blown out to the hot air delivery section 4 and delivered into the drying chamber section 3 via the hot air delivery section 4.

[0025] Therefore, in the present invention, the heat source (heat source of the hot air generating section 5) for obtaining the desired temperature and specified amount of hot air to be sent to the hot air discharge section 4 of the drying chamber 3 is configured to be heated by an electric heater section 6 without using a steam heat exchanger that requires boiler heating, thereby making it possible to realize an environmentally friendly drying device that can meet the demand for CO2 reduction.

[0026] In addition, since the drawn-in air is mixed with the heated air heated by the heater and the circulated exhaust hot air, the temperature and amount of the heated air can be reduced, energy efficiency can be improved, and electricity can be saved, making the hot air generating unit 5 even more environmentally friendly.

[0027] Furthermore, even when drying a coating film in which there is a risk of generating dangerous gases such as flammable gases during drying in the exhaust hot air, which is mixed to increase efficiency, the hot air generating section 5 is configured to not heat the exhaust hot air but to heat the drawn-in outside air with a heater, resulting in a hot air generating section 5 that is excellent in safety and can employ the heater heating method.

[0028] For example, the electrode film of a lithium ion battery is formed by coating the upper surface of a substrate 2 such as aluminum or copper foil with an electrode film and drying it. When drying this electrode film, as the binder in the electrode film (the substance that bonds the electrode film to the substrate) dries, there is a possibility that flammable and dangerous gases will be generated. To ensure that this concentration does not reach a dangerous level, a gas sensor must be installed to monitor it, and the amount of exhaust hot air circulated must be controlled based on this monitoring. For this reason, in the past, a steam type heat exchanger heated by a boiler was used instead of heater heating. However, in the present invention, since the exhaust hot air is not heated even when drying such a coating film, a heater heating method can be used. Therefore, a large amount of exhaust hot air can be circulated and mixed. Furthermore, as a result, the heating energy required to obtain the temperature and amount of heater heated hot air to be mixed with the exhaust hot air can be reduced. This makes it possible to realize a hot air drying device equipped with an innovative hot air generating unit that is excellent in environmental friendliness, energy efficiency, and safety. EXAMPLES

[0029] A specific embodiment of the present invention will now be described with reference to the drawings.

[0030] In this embodiment, the present invention is applied to a drying device provided in a coating device 1 in which a film-like object to be coated (substrate 2) is pulled out from a take-up roll 15 and transported via an opposing support roller 17 that faces a nozzle portion 16 of the coating device 1, a coating liquid is ejected from an ejection hole at the tip of the nozzle portion 16 to coat one side (top surface) of the film-like substrate 2 supported by the opposing support roller 17, and the coated film-like substrate 2 is then transported horizontally through a drying chamber portion 3 of the drying device to be dried and wound up around a recovery roll 18.

[0031] That is, the drying device in this embodiment is provided downstream of the film coating device 1 configured to coat the upper surface of the substrate 2 with the coating liquid in the form of a film by transporting the film-like substrate 2 facing the nozzle portion 16 toward the nozzle portion 16 while ejecting the coating liquid from the tip outlet hole of the nozzle portion 16, and is configured to transport the film-like substrate 2 having its upper surface coated by the coating device 1 and dry the coating film.

[0032] Specifically, although not shown, the configuration is such that the drying chamber section 3 is configured with multiple main body sections (drying chamber forming sections 11) arranged side by side on the left and right, through which the film-like substrate 2 is transported and passed via left and right transport entrance / exit sections, and (although the illustration is simplified) a number of support rollers 19 are provided at intervals within this drying chamber section 3 to support the substrate 2, and hot air blowing sections 4 are provided above and below the substrate 2 that is transported while supported by these support rollers 19, thereby drying it with hot air.

[0033] Specifically, a large number of support rollers 19 are horizontally arranged in parallel inside the drying chamber 3, the film-like substrate 2 is passed over these support rollers 19, and while this film-like substrate 2 is taken up and transported horizontally, the coated surface (coating film) on the upper surface of this substrate 2 is dried by the heat of hot air from the hot air blowing unit 4. Note that it is also possible to provide hot air blowing units above and below and transport the substrate without contacting it while drying the coated surface (coating film) by a floating drying method.

[0034] In this embodiment, hot air blowing sections 4 are provided at the bottom and top between each of the support rollers 19 in the drying chamber 3. As in the drying device having the configuration shown in the above-mentioned prior patent document developed by the applicant, the hot air blowing section 4 located below the support roller 19 is provided with a Coanda nozzle section 20 that produces a Coanda effect, that is, a force that blows hot air in a specified direction to pull the substrate 2 downward, thereby pressing the substrate 2 against the support roller 19.

[0035] In this embodiment, the drying chamber 3 is configured to include a hot air generating section 5 that generates hot air to be sent to each hot air sending section 4 of each drying chamber forming section 11 and sends the hot air to the hot air sending section 4.

[0036] Specifically, the hot air generating section 5 which sends hot air to the hot air discharging section 4 on the upstream side of the transport of the substrate 2 in each drying chamber forming section 11 of the drying chamber section 3, i.e., the hot air discharging section 4 in the drying chamber forming section 11 on the upstream side of the transport where flammable gas may be generated until the coating film is dried to a certain extent, has a route configuration consisting of a heater heating generating section 7 which heats the air (outside air) drawn in using an electric heater section 6 to generate hot air, a mixing section 8 (in this embodiment, a simple pipe confluence section) which draws in and mixes the heater-heated hot air generated by the heater heating generating section 7 and the exhaust hot air exhausted from the drying chamber section 3 and blows out this mixed hot air, an air blowing section 9 for drawing in and blowing out this blowing negative pressure, and a filter 22, and the mixed hot air of the desired temperature drawn in and mixed by the air blowing section 9 is blown out in this manner via the filter 22 to the hot air blowing section 4 at each location in the drying chamber section 3.

[0037] To explain further, in the hot air generating section 5 of this embodiment, the heater-heated hot air generated in the heater heating generation section 7 and exhaust hot air which is obtained by branching off a portion of the exhaust hot air exhausted from the drying chamber section 3 and drawing in a predetermined amount of it through a valve 21 are drawn in and mixed into a mixing section 8 by the negative air blowing pressure, and the blowing section 9 is provided at a piping position where this drawn in and mixed mixed hot air is blown out to the hot air delivery section 4 of the drying chamber section 3, so that the exhaust hot air which may contain flammable gases, etc. cannot be heated by the heater section 6 of the heater heating generation section 7.

[0038] In addition, this embodiment is configured to include a hot air temperature control unit C that controls the valve 21, the heating degree of the heater unit 6 (amount of heater heating power) or the blowing degree of the blower unit 9 (fan rotation speed) according to the mixing ratio of the heater heated hot air and the exhaust hot air so that the temperature of the mixed hot air sent to each hot air delivery unit 4 is the desired temperature, for example 120°C, and a specified flow rate.

[0039] Specifically, the configuration may include a control unit that controls all of these, but in this embodiment, for example, the adjustment settings of the valve 21 that circulates the exhaust hot air and the adjustment settings of the rotation speed of the blower unit 9 are set by manual input, and the heating intensity of the heater unit 6 is controlled according to the mixture ratio based on the temperature of the temperature sensor 10 that detects the temperature of the mixed hot air sent to the hot air delivery unit 4, and feedback control is performed to achieve the desired temperature.

[0040] For example, to improve energy efficiency, the amount of outside air to be heated by the heater can be reduced to 10% or 20% by setting the mixture rate of the circulated exhaust hot air to 90% or 80%, and because this exhaust hot air is 90°C to 80°C and can be circulated and mixed in a specified amount, the degree of heating of the drawn-in outside air by the heater section 6 can be reduced. However, as the amount of drawn-in outside air decreases, the temperature of the mixed hot air must be raised to 120°C, so the output of the heater section 6 must be increased so that the temperature of the heater-heated hot air becomes quite high, and it is difficult to increase the mixture rate of the exhaust hot air too much. These are studied and adjusted, and the above-mentioned sections are configured to be set or controlled.

[0041] In this embodiment, taking these factors into consideration, the hot air temperature is set and controlled according to the desired temperature, flow rate, and mixing ratio, and in this embodiment, the hot air temperature control unit C is configured to control the heating intensity of the heater section 7 based on the temperature sensor 10.

[0042] Therefore, by simply controlling the heating intensity (heater heating power) of the heater section 3, hot air of the desired temperature and flow rate can be supplied efficiently and easily, making it possible to realize a hot air generating section 5 that is energy efficient and has excellent environmental friendliness and safety, as described above.

[0043] In addition, in this embodiment, as described above, a temperature sensor 10 is provided for detecting the temperature of the mixed hot air that is blown out to the hot air blowing section 4 of the drying chamber section 3, and the hot air temperature control section C is configured to control the heating intensity (heater heating power) of the heater section 6 based on the temperature detected by this temperature sensor 10, thereby enabling stable temperature control (temperature management) and maintaining the drying performance of the hot air drying device.

[0044] In this embodiment, the drying chamber section 3 has a configuration in which a plurality of drying chamber forming sections 11 are arranged in parallel in the conveying direction of the base material 2, and the downstream hot air generating section 12 that generates hot air in the hot air delivery section 4 provided in the drying chamber forming section 9 on the downstream side of conveyance and sends it to the hot air delivery section 4 is not the hot air generating section 5, but a heater section 6 (hot air generating section 7) that generates hot air to be sent to the drying chamber forming section 11 on the downstream side of conveyance, i.e., the drying end side, because drying has progressed sufficiently and there is no risk of containing a dangerous concentration or more of flammable gas. The air blowing section 9 is provided with a hot air temperature control section C which controls the valve 21 and the heating degree (heater heating power amount) of the heater section 6 or the blowing degree (fan rotation speed) of the blowing section 9 according to the mixing ratio of outside air and the exhaust hot air, similar to the hot air generating section 5. The heater-heated mixed hot air of the desired temperature generated by the circulating mixing heater heating generating section 13 is sent to the hot air blowing section 4 provided in the drying chamber forming section 9 on the downstream side of the conveying direction.

[0045] That is, in order to further increase energy efficiency, the downstream hot air generating section 12 which generates the hot air to be sent to the drying chamber forming section 11 on the drying end side is configured to heat the mixed hot air, which is a mixture of exhaust hot air and outside air, with a heater and send the hot air of the desired temperature to the hot air delivery section 4. This makes it possible to realize a hot air type dryer with even better energy efficiency.

[0046] In addition, in this embodiment, both the hot air generating section 5, which sends hot air to the hot air delivery section 4 on the upstream side of the transport, and the downstream hot air generating section 12, which sends hot air to the hot air delivery section 4 on the downstream side of the transport, are equipped with a gas sensor 14 for detecting the degree to which the exhaust hot air contains flammable gases, thereby monitoring the content of flammable gases and the like to ensure safety.

[0047] Incidentally, the present invention is not limited to the present embodiment, and the specific configuration of each component can be designed as appropriate. [Explanation of symbols]

[0048] 1 Coating device 2 Base material 3 Drying room 4 Hot air outlet section 5 Hot air generation section 6 Heater section 7 Heater heating unit 8 Mixing section 9 Blower 10 Temperature Sensor 11 Drying chamber forming section 12 Downstream hot air generation section 13 Circulating mixing heating generation section 14 Gas Sensor 15 Winding roll 16 Nozzle section 17 Support roller 18 Collection Roll 19 Support roller 20 Coanda nozzle part 21 Valve 22 Filters

Claims

1. A hot air drying device comprising: a drying chamber section through which a film-like substrate is conveyed and passed after being coated with a coating liquid by a coating device and discharged from the coating device; and a hot air delivery section that delivers hot air to dry the coating liquid applied to the substrate; A hot air generating unit is provided to generate hot air to be sent to the hot air sending section of the drying chamber and send the hot air to the hot air sending section, The hot air generating section which sends hot air to the hot air delivery section at least on the upstream side of the transport of the base material in the drying chamber is configured to include a heater heating generation section which heats air drawn in with a heater section to generate hot air, a mixing section which mixes the heater heated hot air generated by the heater heating generation section with exhaust hot air exhausted from the drying chamber and delivers mixed hot air, and an air blowing section, and the mixed hot air drawn in and mixed by the air blowing section is delivered to the hot air delivery section of the drying chamber, A hot air drying device characterized in that it is configured to include a hot air temperature control unit that controls the heating degree of the heater section or the blowing degree of the blower section in accordance with a mixing ratio of the heater-heated hot air and the exhaust hot air so that the temperature of the mixed hot air becomes a desired temperature.

2. The hot air drying device according to claim 1, characterized in that the hot air generating section draws in and mixes the heater-heated hot air generated by the heater heating generating section and the exhaust hot air exhausted from the drying chamber section by using a negative air pressure, and the air blowing section is provided at a position where it blows and delivers the drawn-in and mixed mixed hot air to the hot air delivery section of the drying chamber section, so that the exhaust hot air is not heated by the heater section of the heater heating generating section.

3. The drying device according to claim 1, characterized in that a temperature sensor is provided for detecting the temperature of the mixed hot air delivered to the hot air delivery section of the drying chamber, and the hot air temperature control section is configured to control the heating intensity of the heater section based on the temperature detected by the temperature sensor.

4. The drying chamber section is configured such that a plurality of drying chamber forming sections are arranged in parallel in the transport direction of the base material, and the downstream hot air generating section that generates hot air at the hot air delivery section provided in the drying chamber forming section on the downstream side of the transport and sends it to the hot air delivery section is not the hot air generating section, but is configured to include a circulating mixing heater heating generation section that heats a mixed hot air obtained by mixing the drawn-in air and the exhaust hot air exhausted from the drying chamber section with the heater section to generate heater-heated mixed hot air, and the air blowing section, and the heater-heated mixed hot air generated by the circulating mixing heater heating generation section is sent to the hot air delivery section provided in the drying chamber forming section on the downstream side of the transport.

5. 5. The hot air drying device according to claim 4, further comprising a gas sensor for detecting the amount of flammable gas contained in the exhaust hot air.

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