Surface fluid heating device

Abstract

To provide a planar fluid heating device in which a fluid contacts a heat-generating part with a large area.SOLUTION: A planar fluid heating device includes a first thermoplastic resin substrate, a second thermoplastic resin substrate, and a channel formed by fusion bonding between the first and second thermoplastic resin substrates, and a planar heating element having a resistance heating coating layer is embedded in the first thermoplastic resin substrate.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a planar fluid heating device. [Background technology]

[0002] Sheet heating elements having a resistive heating layer formed by coating with a heat-generating paint containing conductive particles such as carbon black and a binder resin are used in various fields such as floor heating, defrosting, melting snow on stairs, pipe heaters, etc. For example, the present inventors have proposed in Patent Document 1 a sheet heating element that can efficiently perform stable heating with less temperature unevenness during heating, and in Patent Document 2 a water-based heat-generating paint capable of generating heat at a higher temperature than conventional ones, and a sheet heating element using the same. Fluid heating devices that use such sheet heating elements to heat fluids such as liquids and gases are known, and are usually formed by wrapping a sheet heating element around the outer surface of a pipe. However, such conventional sheet heating elements have a ratio of the circumference, which is the heat generating part, to the cross-sectional area of ​​the pipe (where r is the radius, and is expressed as 2πr / πr 2 = 2 / r) and heat efficiently, the only way is to make the pipes thinner, but making the pipes thinner reduces the fluid transportability.

[0003] In addition, heating devices are used to culture microorganisms and human-derived cells within a specific temperature range (for example, for human-derived cells, this is around 37°C, and cells are destroyed at temperatures above 42°C). In order to prevent contamination (contamination due to the introduction and proliferation of unwanted bacteria during culture), there is a demand for heating devices that can be used only once (single-use), and therefore inexpensive. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2016-110757 A [Patent Document 2] Patent No. 6927612 Summary of the Invention [Problem to be solved by the invention]

[0005] The object of the present invention is to provide a planar fluid heating device in which the area over which the fluid comes into contact with a heat generating portion is large. [Means for solving the problem]

[0006] The present invention is intended to solve the above problems, and the specific means are as follows: 1. A liquid crystal display device having a first thermoplastic resin substrate, a second thermoplastic resin substrate, and a flow path formed by fusion between the first and second thermoplastic resin substrates, A planar fluid heating device, comprising: a planar heating element having a resistive heating coating layer embedded in the first thermoplastic resin base. 2. The first and second thermoplastic resin substrates are made of polyethylene; The planar fluid heating device according to 1., wherein the planar heating element comprises a paper substrate coated with the resistive heating coating layer. 3. The planar fluid heating device according to 1 or 2, further comprising a flow-impeding portion formed by fusion between the first and second thermoplastic resin substrates. 4. The planar fluid heating device according to claim 3, wherein the flow impeding portion is formed on a non-heating area of ​​the planar heating element. 5. The flow inhibition portion is formed in a pair of combs facing each other such that the teeth of one comb are located between the adjacent teeth of the other comb, 5. The planar fluid heating device according to 3. or 4., wherein the comb teeth are tapered. 6. The planar fluid heating device according to any one of 1. to 5., wherein the length of the flow path is 1.4 times or more the length of a straight line connecting the inlet and the outlet. Effect of the Invention

[0007] The planar fluid heating device of the present invention is planar, and the area in which the fluid comes into contact with the heat generating portion is large, so that efficient heating can be achieved. The planar fluid heating device of the present invention, which is mainly made of paper and polyethylene, is unlikely to cause delamination because the paper and polyethylene can be firmly fused together. The planar fluid heating device of the present invention, which is mainly made of paper and polyethylene, is very inexpensive and can be sterilized by gamma ray irradiation, so it can be suitably used for heating culture solutions and infusions for microorganisms and cells, and can also be suitably used for single-use purposes. The planar fluid heating device of the present invention can control the shape of the flow path by forming a flow inhibition portion. In particular, in the planar fluid heating device of the present invention, in which the flow inhibition portion is formed in a pair of combs facing each other such that one comb tooth is located between the adjacent comb teeth of the other comb, and the comb teeth are tapered, bubbles can be easily removed when liquid or sol is flowed as a fluid, so that dry heating can be prevented and abnormal heating of the planar heating element can be prevented. [Brief description of the drawings]

[0008] [Figure 1] 1 is an exploded view of a planar fluid heating device according to a first embodiment of the present invention; [Diagram 2] 1 is a schematic diagram of a planar fluid heating device according to a first embodiment of the present invention; [Diagram 3] 1 is a schematic diagram of a planar heating element provided in a planar fluid heating device according to a first embodiment of the present invention; [Figure 4] 1 is a diagram showing a state in which a fluid flows in a planar fluid heating device according to a first embodiment of the present invention; [Diagram 5] FIG. 4 is a schematic diagram of a planar fluid heating device according to a second embodiment of the present invention. [Figure 6] 4 is a schematic diagram of a planar heating element provided in a planar fluid heating device according to a second embodiment of the present invention. FIG. [Figure 7] FIG. 4 is a diagram showing a state in which a fluid flows when a planar fluid heating device according to a second embodiment of the present invention is suspended. [Figure 8] FIG. 4 is a schematic diagram of a planar fluid heating device according to a third embodiment of the present invention. [Figure 9] 4 is a schematic diagram of a planar heating element provided in a planar fluid heating device according to a third embodiment of the present invention. FIG. [Figure 10]FIG. 4 is a diagram showing a state in which a fluid flows in a planar fluid heating device according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] "First embodiment" Figures 1 and 2 are exploded views and schematic diagrams of a planar fluid heating device 100 which is a first embodiment of the present invention, Figure 3 is a schematic diagram of the planar heating element 14 provided in the planar fluid heating device 100, and Figure 4 shows the flow of fluid in the planar fluid heating device 100.

[0010] The planar fluid heating device 100 has a first thermoplastic resin base 11, a second thermoplastic resin base 12, a flow path 13 formed therebetween by fusion, and a planar heating element 14 embedded in the first thermoplastic resin base 11. The first thermoplastic resin base 11 and the second thermoplastic resin base 12 are integrated by fusion to form the planar fluid heating device 100. A plurality of flow inhibition parts 133 are provided by fusion between the first thermoplastic resin base 11 and the second thermoplastic resin base 12. The flow channel 13 is formed so as to bend back four times from the inlet 131 to the outlet 132 by the flow inhibition parts 133.

[0011] The first thermoplastic resin base 11 comprises a first thermoplastic resin sheet 111 and a second thermoplastic resin sheet 112, and the first thermoplastic resin sheet 111 / sheet heating element 14 / second thermoplastic resin sheet 112 are laminated in this order from the side furthest from the second thermoplastic resin base 12. The first and second thermoplastic resin sheets 111, 112 are integrated by being thermally fused with the sheet heating element 14 sandwiched therebetween to form the first thermoplastic resin base 11. The sheet heating element 14 includes a paper substrate 141 and a resistive heating coating layer 142 formed on the paper substrate 141. The resistive heating coating layer 142 is provided so as to be on the flow path 13 side.

[0012] "Thermoplastic resin base, thermoplastic resin sheet" The first and second thermoplastic resin substrates 11 and 12, as well as the first thermoplastic resin sheet 111 and the second thermoplastic resin sheet 112, are all made of a thermoplastic resin. There is no particular limitation on the thermoplastic resin, and polyethylene, polypropylene, polystyrene, polyester, polycarbonate, polyamide, polyimide, acrylic resin, fluororesin, etc. can be used, and different types of thermoplastic resins that can be thermally fused to each other can also be used in combination. Among these, it is preferable to use polyethylene, which is inexpensive and can be sterilized by gamma ray irradiation, or polypropylene and fluororesin, which can be sterilized by autoclave. As the polyethylene, high density polyethylene (HDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), etc. can be used without any particular limitation. As the fluororesin, PTFE, PFA, FEP, etc. can be used without any particular limitation.

[0013] The first thermoplastic resin substrate 11 is formed by laminating a first thermoplastic resin sheet 111, a sheet heating element 14 and a second thermoplastic resin sheet 112 in this order. In the first thermoplastic resin substrate 11, the first thermoplastic resin sheet 111 and the second thermoplastic resin sheet 112 may have the same thickness or different thicknesses. The first thermoplastic resin sheet 111 and the second thermoplastic resin sheet 112 may have different thicknesses in different parts. For example, the part on the resistance heating coating layer 142 may be thinner than the other parts. In particular, the first and second thermoplastic resin sheets 111 and 112, particularly the first thermoplastic resin sheet 111 located on the flow path 13 side, are preferably thin from the viewpoint of heat transfer, but if they are too thin, their strength decreases and they become easily torn. Therefore, the part on the resistance heating coating layer 142 of the first thermoplastic resin sheet 111 is preferably 100 μm or more. In addition, if the thickness of the first and second thermoplastic resin sheets 111 and 112 is too thin compared to the step generated inside by the embedded planar heating element 14, holes may be formed because they cannot follow the step during heat fusion. Therefore, the thickness of the first and second thermoplastic resin sheets 111, 112 is preferably 0.8 times or more, more preferably 1.0 times or more, and even more preferably 1.2 times or more of the step that exists inside when sealing the sheet heating element 14. Note that the sheet heating element 14 may not have a uniform thickness overall because lead wires, thermocouple cords, etc. are connected to it.

[0014] In the planar fluid heating device 100, in order to prevent defects such as cracks from occurring in the resistance heating coating layer 142 of the planar heating element 14, it is not preferable that the first thermoplastic resin base 11 in which the planar heating element 14 is embedded is significantly deformed. By using a material having flexibility and suppleness as the second thermoplastic resin base 12 and fusing the second thermoplastic resin base 12 to the first thermoplastic resin base 11 in a state where there is a margin, even if pressure from the fluid is applied, the second thermoplastic resin base 12 can be deformed to expand and reduce the pressure, so that deformation of the first thermoplastic resin base 11 can be suppressed. Therefore, the thickness of the second thermoplastic resin base 12 is preferably 800 μm or less, and more preferably 500 μm or less. Moreover, if it is too thin, tears and holes are likely to occur during fusing, so the thickness is preferably 100 μm or more. The thickness of the second thermoplastic resin base 12 is preferably 80% or less of the thickness of the first thermoplastic resin base 11, and more preferably 60% or less. Furthermore, the area of ​​the second thermoplastic resin substrate 12 facing the flow path 13 is preferably 1.02 times or more, and more preferably 1.05 times or more, the area of ​​the first thermoplastic resin substrate 11 facing the flow path 13. If this area ratio becomes too large, the ratio of the length of the heat generating portion to the cross-sectional area of ​​the flow path 13 becomes small, so this area ratio is preferably 1.5 times or less, more preferably 1.4 times or less, even more preferably 1.25 times or less, and even more preferably 1.15 times or less.

[0015] "Surface heating element" The sheet heating element 14 comprises a paper substrate 141 and a resistive heating coating layer 142 formed on the paper substrate 141 . Conductive sections 143a, b are provided on both sides of the paper base material 141 with non-coated sections between them and the resistive heating coating layer 142, and a pair of comb-shaped electrodes 144a, b are formed from the conductive sections 143a, b toward the resistive heating coating layer 142, facing each other such that one electrode is located between adjacent electrodes. Lead wires 145a, b are connected to the conductive sections 143a, b. The comb-shaped electrodes 144a, b only need to be in contact with the resistive heating coating layer 142, and can also be formed between the paper base material 141 and the resistive heating coating layer 142.

[0016] "Paper base material" The paper base material 141 can be any paper that can be used without particular limitations as long as the heat-generating paint can be applied onto its surface to form a uniform resistance heating coating layer 142, but uncoated paper is preferred because it has excellent adhesion to the resistance heating coating layer 142 and the first and second thermoplastic resin sheets 111, 112. The basis weight of the paper base material 141 is 40 g / m 2 More than 300g / m 2 The basis weight of the paper base material 141 is preferably 40 g / m or less. 2 If the thickness is less than 300g / m, the heat-generating paint may bleed through to the other side. 2 If this value exceeds the limit, the paper base material 141 will become too rigid, and when force is applied to cause the paper base material 141 to bend, etc., the ends of the paper base material 141 may be prone to peeling off from the first and second thermoplastic resin sheets 111, 112 or tearing of the first and second thermoplastic resin sheets 111, 112.

[0017] Resistance heating coating layer The resistive heating coating layer 142 is formed by applying a heat-generating paint containing at least a conductive material and a binder resin onto the paper substrate 141 and drying it. The heat-generating paint may be either water-based or organic solvent-based, but water-based paint is preferred because it places less strain on workers and the environment, and is safer with no risk of fire or explosion.

[0018] The conductive material can be any of those conventionally used in resistance heating coating layers without any particular limitations, and examples of such conductive materials include carbon-based conductive materials such as carbon black, graphite, carbon nanotubes, fullerenes, and carbon fibers; metal-based conductive materials such as gold, silver, copper, and nickel; and ceramic-based conductive materials such as tungsten carbide, titanium nitride, zirconium nitride, and titanium carbide. Of these, carbon-based conductive materials are preferred because they have small particle sizes and are inexpensively available. The conductive materials can be used alone or in combination of two or more types. The conductive material is preferably contained in a proportion of 30 parts by weight or more and 70 parts by weight or less per 100 parts by weight of the solid content of the resistance heating coating layer.

[0019] The binder resin can be used without any particular limitation as long as it can be dissolved or dispersed in the heat-generating coating material, and for example, one or a mixture of two or more of polyimide resin, silicone resin, polyamide resin, polyurethane resin, polyester resin, acrylic resin, vinyl resin, epoxy resin, etc. Among these, one or more of polyimide resin, silicone resin, and polyamide resin are preferred because of their excellent heat resistance. The binder resin is preferably contained in an amount of 15 parts by weight or more and 50 parts by weight or less per 100 parts by weight of the solid content of the resistance heating coating layer.

[0020] When the heat-generating paint is an aqueous paint, it is preferable that the paint contains water-swellable synthetic mica. The water-swellable synthetic mica takes up water between its layers and swells. An aqueous paint containing swollen mica exhibits thixotropy, that is, the viscosity decreases when shear stress is applied and increases when the stress is no longer applied. Therefore, an aqueous heat-generating paint containing water-swellable synthetic mica is easy to apply and does not drip easily after application, making it easy to form a uniform resistance heat-generating coating layer. When water-swellable synthetic mica is contained, it is preferable that the water-swellable synthetic mica is contained in a ratio of 3 parts by weight or more and 40 parts by weight or less per 100 parts by weight of the solid content of the resistance heating coating layer.

[0021] The water-swellable synthetic mica preferably has an average particle size (median size) of 2 μm or more and 20 μm or less, which is derived from the volume distribution measured by the laser diffraction scattering method. If the average particle size is within the above range, the dispersibility and coatability in the water-based heat-generating paint are excellent, and a uniform coating film (resistance heat-generating coating layer) is easily formed. The average particle size is more preferably 2 μm or more and 10 μm or less.

[0022] The heat-generating coating material may contain additives such as dispersants, leveling agents, antifoaming agents, and hardeners, within limits that do not impair the effects of the present invention. The solids concentration of the heat-generating paint is adjusted so that the viscosity is suitable for the coating method, etc. The solids concentration can be, for example, about 5% by weight or more and 50% by weight or less, depending on the viscosity required for the coating method, etc.

[0023] The resistive heating coating layer 142 is formed by applying a heat-generating paint onto the paper substrate 141 and drying it. The resistive heating coating layer 142 may be formed from a single heat-generating paint, or may be formed by applying multiple types of heat-generating paint with different compositions. The resistive heating coating layer 142 may be a single layer or multiple layers that are at least partially overcoated. Since the resistive heating coating layers 142 are connected in parallel, the higher the resistance value, the lower the heat generation temperature, and the lower the resistance value, the higher the heat generation temperature. By adjusting the composition of the heat-generating paint, the thickness of the resistive heating coating layer, the spacing of the comb-shaped electrodes, etc., the resistive heating coating layer 142 can be divided into low resistance regions and high resistance regions, allowing the heat generation temperature to be different for each region.

[0024] The resistive heating coating layer 142 is connected to comb-shaped electrodes 144a and 144b formed of conductive ink, conductive parts 143a and 143b, and lead wires 145a and 145b connected to the conductive parts 143a and 143b by conductive paste, and is energized by connecting the other ends of the lead wires 145a and 145b to an external power source. As the conductive ink and conductive paste, known materials can be used, and for example, materials containing conductive particles such as copper or silver that satisfy the desired properties such as coating property, adhesion, and fixation can be used. As the lead wires 145a and 145b, known materials can be used, and for example, metal wires such as copper wire, nickel wire, copper-plated nickel twisted wire, copper-plated aramid fiber, etc. can be used without any particular restrictions, but it is preferable that the lead wires 145a and 145b are an aggregate of multiple fibers because they can be crushed and flattened by the pressure during heat fusion in the manufacturing process. The method for energizing the resistive heating coating layer 142 is not limited, and known methods can be used, and for example, conductive adhesive tape can be used instead of the conductive paste, and electricity can also be passed wirelessly. When the lead wires 145a and b are used, the lead wires 145a and b may be led from different locations or from the same location to the outside of the first thermoplastic resin base 11. When a temperature sensor such as a thermocouple is sealed inside the first thermoplastic resin base 11, the cord of this sensor may also be led from either different locations or the same location to the outside. When a temperature sensor is installed, the measurement location is not particularly limited, but it can be measured at one or more of the inlet, outlet, midway through the flow path, etc., and it is preferable to measure at the outlet.

[0025] Since the resistive heating coating layer 142 generates heat when electricity is passed through it, the region of the resistive heating coating layer 142 sandwiched between the opposing comb-shaped electrodes 144a, b is the heat generating region. The regions other than this heat generating region are the non-heat generating regions of the sheet heating element 14, specifically the non-coated parts where the resistive heating coating layer 142 is not applied and the comb-shaped electrodes 144a, b formed on the resistive heating coating layer 142 are the non-heat generating regions. The comb-shaped electrodes 144a, b on the resistive heating coating layer 142 are non-heat generating regions because electricity passes through the comb-shaped electrodes 144a, b, which have a low resistance, and does not pass through the resistive heating coating layer 142, which has a high resistance.

[0026] The paper base material 141 has a non-heat generating area adjacent to the heat generating area of ​​the resistance heating coating layer 142. Thermoplastic resins may undergo deformation such as expansion / contraction due to heat, but the non-heat generating area provided adjacent to the heat generating area functions as a support that suppresses deformation of the thermoplastic resin. Therefore, the planar fluid heating device of the present invention can suppress thermal deformation of the thermoplastic resin base or thermoplastic resin sheet, and suppress deformation of the planar fluid heating device itself. Also, the paper base material 141 can have an opening by hollowing out at least a part of the non-heat generating region. The first thermoplastic resin base 11 is less likely to deform because the sheet heating element 14 is embedded therein, but the portion not including the paper base material 141 can deform to some extent. By providing an opening in the paper base material 141, a part of the first thermoplastic resin base 11 becomes more easily deformable, and pressure from the fluid can be alleviated, preventing tearing and liquid leakage. For example, when an opening is provided in the paper base material 141, it can be provided between the resistive heating coating layer 142 and the conductive parts 143a, b.

[0027] "Flow path" The flow path 13 is formed by fusing the first thermoplastic resin substrate 11 and the second thermoplastic resin substrate 12. At this time, the first thermoplastic resin substrate 11 and the second thermoplastic resin substrate 12 are fused to form a flow hindering portion 133, so that the flow path 13 can be formed in a desired shape. Note that the flow path 13 and the flow hindering portion 133 can also be formed by sandwiching an intermediate substrate, at least the surface of which is made of a thermoplastic resin and has a flow path pattern, between the first thermoplastic resin substrate 11 and the second thermoplastic resin substrate 12 and heat fusing the respective substrates at their interfaces. In the planar fluid heating device 100 of the first embodiment, the first thermoplastic resin base 11 and the second thermoplastic resin base 12 are fused to each other on the comb-shaped electrodes 144a, b which are non-heat generating regions, thereby forming a plurality of flow inhibition portions 133. By forming the flow inhibition portions 133 on the comb-shaped electrodes 144a, b which are non-heat generating regions, the flow inhibition portions 133 are not heated to a high temperature, and therefore it is possible to prevent holes from being formed in the flow path due to deformation of the flow inhibition portions 133, etc.

[0028] The shape and length of the flow path 13 are not particularly limited, and can be adjusted by the shape and position of the flow inhibition portion 133, and branching and merging are also possible. The length of the flow path 13 is preferably 1.4 times or more the length of the straight line connecting the inlet 131 and the outlet 132. By lengthening the flow path 13, the time for which the fluid is heated can be increased, and the fluid can be heated efficiently. The length of the flow path 13 is more preferably 2 times or more the length of the straight line connecting the inlet 131 and the outlet 132, further preferably 4 times or more, and even more preferably 6 times or more. Here, the length of the flow path means the shortest distance connecting the inlet and the outlet within the flow path, and when there are multiple flow paths due to branching or the like, means the average value of the shortest distances of each flow path.

[0029] The flow channel 13 preferably has a ratio of the maximum width to the minimum width (maximum width / minimum width) over the entire length of the flow channel of 2.0 or less. If the difference in flow channel width is large, fluid may accumulate in the narrow portion, increasing the pressure and causing breakage. This ratio is more preferably 1.8 or less, even more preferably 1.5 or less, and even more preferably 1.3 or less. The width of the flow channel means the shortest distance between one side of the flow channel and the opposing other side.

[0030] Furthermore, the resistive heating coating layer can be patterned into regions of different resistance and the desired locations can be made hotter or colder, allowing the temperature to be adjusted at each desired location in the flow path. For example, by making the inlet side colder, the flow can be gradually heated, preventing a sudden increase in temperature. On the other hand, by making the inlet side hotter, the desired temperature can be reached more quickly, and the desired temperature can be maintained for a longer period of time.

[0031] "Second embodiment" A planar fluid heating device 200 according to a second embodiment of the present invention and a planar heating element 24 provided in the planar fluid heating device 200 according to the second embodiment are shown in Figures 5 and 6. In this specification, the same members as those in the first embodiment are denoted by the same reference numerals. In the planar fluid heating device 200, the comb-like electrodes 244a, b of the planar heating element 24 are formed in a tapered shape that becomes thinner toward the tip, and the opposing comb-like electrodes 244a, b are formed so that opposing sides are parallel. By forming the tapered comb-like electrodes 244a, b so that opposing sides are parallel, the width of the resistive heating coating layer 242 between the comb-like electrodes 244a, b becomes the same and the resistance value also becomes the same, so that it is possible to prevent current from concentrating in low resistance parts and causing abnormal heating.

[0032] In addition, in the planar fluid heating device 200, a tapered flow inhibition portion 233 is formed by fusing the first thermoplastic resin base and the second thermoplastic resin base on the tapered comb electrodes 244a, b, which are non-heat-generating areas. FIG. 7 shows the flow of fluid in the planar fluid heating device 200. As shown in FIG. In a planar fluid heating device, when liquid, sol, etc. are caused to flow, they are generally caused to flow from below to above. When the planar fluid heating device 200 is suspended and fluid is allowed to flow from below to above, the upper surface of the flow path 23 (the lower surface of the flow obstruction section 233) is inclined upward in the flow direction, so that bubbles can easily escape with the flow and dry-burning, in which the heat generating area is heated while covered in gas, can be prevented.

[0033] "Third embodiment" A planar fluid heating device 300 according to a third embodiment of the present invention and a planar heating element 34 provided in the planar fluid heating device 300 according to the third embodiment are shown in FIGS. 8 and 9, respectively. The sheet heating element 34 is formed by dividing the resistive heating coating layer 342, with non-coated areas between them. The non-coated areas are naturally non-heat generating regions, and flow inhibition areas 333 are formed on the non-coated areas with slits between them, and the slits are alternately opened on adjacent non-coated areas. The planar fluid heating device 300 has two inlets 331 and one outlet 332, and the fluids are mixed uniformly while flowing through the flow path 33 by passing through slits provided so as to open alternately on adjacent non-coated areas. Therefore, the planar fluid heating device 300 can be suitably used as a flow reactor.

[0034] The planar fluid heating device of the present invention is not limited to the above-mentioned first to third embodiments. For example, a flow path for heating the same or another fluid or a heat insulating layer containing air can be formed by fusing a third thermoplastic resin substrate to at least one surface of the surface fluid heating device. Furthermore, a flow path for cooling can be formed by providing another flow path downstream after the end of heating and passing a fluid that exchanges heat with the heated fluid.

[0035] There is no particular limitation on the use of the planar fluid heating device of the present invention, and the fluid to be heated therein may be any fluid that flows, and is not limited to liquid, but may also be gas or sol. For example, since the melting point of polyethylene is about 95 to 140°C, when polyethylene is used as a thermoplastic resin, it can be used in applications where the heating temperature is lower than that, and can be used as a planar fluid heating device for heating cell or microbial culture solutions, a flow reactor, or a planar fluid heating device for preventing condensation of exhaust gas containing a lot of moisture. EXAMPLES

[0036] "Example 1" An aqueous heat-generating paint containing carbon black and polyimide resin was mixed with water-swellable synthetic mica (average particle size 5 μm or less) and deionized water, and stirred for 6 minutes using a planetary mixing and degassing device (Kurashiki Boseki Co., Ltd., Mazerustar KK-1000W) using a standard mixing and degassing program for high-viscosity materials to prepare an aqueous heat-generating paint containing 37.2% by weight of carbon black, 33.9% by weight of polyimide resin, 8.0% by weight of water-swellable synthetic mica, and 20.8% by weight of water. The prepared water-based heat-generating paint was applied to a paper substrate (Kent paper (uncoated paper) Be051, manufactured by Sugako Kogyo Co., Ltd., basis weight 43 g / m 2 A doctor blade was used to apply a coating of 150 mm wide, approximately 210 mm long and 20 μm thick to the widthwise center of the paper substrate, which was then baked at 200° C. for 1 hour to form a resistance heating coating layer. Next, silver paste was applied to both sides of the paper substrate in the widthwise direction in a width of 5 mm, and six silver paste lines were applied in total, three lines each with a width of 5 mm and 50 mm intervals, from the silver paste-coated areas on both sides to the other end of the resistance heating coating layer, and then the coating was baked at 100° C. for 30 minutes and then at 150° C. for 30 minutes to form a conductive part and a comb-shaped electrode.

[0037] The part of the resistive heating coating layer that contained the heat generating region was sandwiched from above and below with thermoplastic resin sheets made of 200 μm thick polyethylene, and then heat-sealed for 10 minutes at 130° C. with a silicone rubber sponge cushioning material in between. As a result, almost the entire surface of the paper base material was embedded in the thermoplastic resin sheets. A flame-retardant polyethylene-coated lead wire was connected to the exposed conductive part with Ag paste and fixed with polyethylene tape. A fluororesin-coated K-type thermocouple sensor was also fixed with polyethylene tape at the location where the outlet was to be installed. The lead wire and thermocouple cord were made to pass through the same polyethylene tube. The part including the lead wire exposed from these thermoplastic resin sheets was sandwiched from above and below with thermoplastic resin sheets made of 500 μm thick polyethylene, and heat-sealed at 130°C for 10 minutes with a silicone rubber sponge cushioning material in between. As a result, the entire surface of the sheet heating element was embedded, and a first thermoplastic resin substrate was obtained.

[0038] A second thermoplastic resin substrate made of polyethylene and 200 μm thick was thermally fused to the first thermoplastic resin substrate around its outer periphery excluding the inlet and outlet and onto the comb-shaped electrodes so that the area ratio (second / first) facing the flow path was 1.1 times that of the first thermoplastic resin substrate, thereby obtaining a planar fluid heating device as shown in Figure 2. [Explanation of symbols]

[0039] Planar fluid heating device 100, 200, 300 First thermoplastic resin substrate 11 First thermoplastic resin sheet 111 Second thermoplastic resin sheet 112 Second thermoplastic resin substrate 12 Channels 13, 23, 33 Inlet 131, 331 Outlet 132, 332 Flow obstruction part 133, 233, 333 Sheet heating element 14, 24, 34 Paper base material 141 Resistance heating coating layer 142, 242, 342 Conductive part 143a, b Comb-shaped electrodes 144a, b, 244a, b Lead wire 145a, b

Claims

1. A thermoplastic resin substrate includes a first thermoplastic resin substrate, a second thermoplastic resin substrate, and a flow path formed between the first and second thermoplastic resin substrates by fusion bonding; A planar fluid heating device, comprising: a planar heating element having a resistive heating coating layer embedded in the first thermoplastic resin base.

2. the first and second thermoplastic resin substrates are made of polyethylene; 2. The planar fluid heating device according to claim 1, wherein the planar heating element comprises a paper substrate coated with the resistive heating coating layer.

3. 3. The planar fluid heating device according to claim 1, further comprising a flow-impeding portion formed by fusion between said first and second thermoplastic resin substrates.

4. 4. The planar fluid heating device according to claim 3, wherein the flow obstruction portion is formed on a non-heat generating region of the planar heating element.

5. the flow inhibition portion is formed in a pair of combs facing each other such that one comb tooth is located between adjacent comb teeth of the other comb, 5. The planar fluid heating device according to claim 3, wherein the comb teeth are tapered.

6. 6. The planar fluid heating device according to claim 1, wherein the length of the flow path is at least 1.4 times the length of a straight line connecting the inlet and the outlet.

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