Heat exchanger

Abstract

The aim is to provide a heat exchanger that can suppress the flow of the fluid being processed, prevent gas from accumulating in the heat transfer section, decompose and clean well, and also allow for coating and lining. The heat exchanger has two flow paths, a first flow path (11) and a second flow path (21), formed concentrically between an inner cylinder (10) and an outer cylinder (20). A spiral heat transfer body (41) is disposed between the inner cylinder (10) and the outer cylinder (20), and the spiral heat transfer body (41) has a roughly triangular cross-sectional shape in an axial sectional view. The space is divided into the first flow path (11) and the second flow path (21) by the spiral heat transfer body (41), and heat exchange occurs between a first fluid (F1) flowing through the first flow path (11) and a second fluid (F2) flowing through the second flow path (21) via the spiral heat transfer body (41).

Description

Technical Field

[0001] This invention relates to a heat exchanger, the purpose of which is to heat or cool liquids, particularly suspensions containing dispersed solids, high-viscosity liquids, or fluids containing vapors, using fluids such as refrigerants, heat transfer media, or steam. Background Technology

[0002] In chemical and food manufacturing processes, as well as in the production of colorants and inkjet printers, there are frequent requirements for rapid cooling and high-speed heating. Furthermore, there is a need to minimize the necessary installation space, resulting in smaller equipment sizes and demanding high-performance heat exchangers. Additionally, heat exchangers with low adhesion, excellent cleanability, pressure resistance, corrosion resistance, and low cost are required.

[0003] Previously, as disclosed in Patent Document 1, heat exchangers were known to have a spiral heat transfer tube disposed in the space formed between the inner cylinder and the outer cylinder, wherein the heat transfer tube is a flow path of one side, and the spiral space sandwiched between the heat transfer tubes in the space is a flow path of the other side, thereby achieving efficient heat exchange between the fluids of one side and the other side.

[0004] However, while the heat exchanger described in Patent Document 1 achieves miniaturization and high performance, the space between the circular cross-section spiral heat transfer tube and the inner or outer circumferential surface of the outer cylinder becomes narrow. This narrow section is prone to blockage or adhesion, and even if the inner and outer cylinders are separated, the narrow section will not disappear unless the spiral heat transfer tube is also separated. Therefore, cleaning is difficult when adhesion occurs in this narrow section, making it impossible to easily confirm whether cleaning has been performed. Furthermore, applying a coating or lining inside the spiral heat transfer tube is practically impossible, and it is also difficult to apply a corrosion-resistant coating or lining in other flow paths due to its structure. Improvements are required from the perspective of corrosion resistance. In particular, it is practically impossible to coat or line the heat transfer tube with corrosion-resistant materials, and even if it were possible, poor mass production and impracticality from a cost perspective would be unavoidable.

[0005] Furthermore, when a suspension containing particles flows through the spiral space formed between the inner and outer cylinders and sandwiched between the heat transfer tubes, and heat exchange occurs between the suspension and the heat medium flowing inside the heat transfer tubes, the suspension sometimes remains in the gap between the heat transfer tubes, i.e., the spiral space. When heat exchange occurs with evaporation, its vapor remains in the heat transfer section, hindering heat exchange and causing it to evaporate.

[0006] Patent document 2 describes a heat exchanger characterized by forming a liquid-side heat transfer tube with a roughly triangular cross-sectional shape into a spiral shape, and arranging a refrigerant-side heat transfer tube in a spiral shape around its outer periphery, thereby connecting the liquid-side heat transfer tube and the refrigerant-side heat transfer tube. However, the heat transfer area is too small, making it suitable only for water heaters and the like, and it cannot achieve miniaturization, easy cleaning, high performance, or low cost.

[0007] Patent Document 3 describes a heat exchanger comprising: a first flow path forming member having a container shape; and a second flow path forming member disposed inside the first flow path forming member in a manner detachable from the first flow path forming member. The diameter of the inner circumferential surface of the container-shaped peripheral wall of the first flow path forming member gradually decreases from the top to the bottom, and a first flow path for heat exchange liquid to flow is formed in the peripheral wall. A spiral second flow path is formed between the inner circumferential surface of the first flow path forming member and the outer circumferential surface of the second flow path forming member, and the second flow path is for the flow of the heat exchanged liquid that exchanges heat with the heat exchange liquid through these inner and outer circumferential surfaces.

[0008] However, as the flow path gradually decreases, the flow velocity through the heat transfer surface also gradually changes, making it difficult to apply to general industry. Furthermore, in the case of heat exchange accompanied by boiling, there are many gas retention sites, which can easily lead to evaporation.

[0009] Prior art literature

[0010] Patent documents

[0011] Patent Document 1: Japanese Patent Application Publication No. 2002-147976

[0012] Patent Document 2: Japanese Patent Application Publication No. 2013-24536

[0013] Patent Document 3: Japanese Patent Application Publication No. 2015-81716 Summary of the Invention

[0014] The problem that the invention aims to solve

[0015] In view of the above, the objective of the present invention is to provide a heat exchanger having a structure suitable for suppressing the fluid being processed and causing gas to stagnate in the heat transfer section.

[0016] Another objective of this invention is to provide a heat exchanger with good cleanability.

[0017] Another objective of the present invention is to provide a heat exchanger capable of decomposition.

[0018] In addition, the present invention aims to provide a heat exchanger that can also be coated or lined.

[0019] Solution for solving the problem

[0020] The heat exchanger of the present invention has two flow paths, a first flow path and a second flow path, arranged in a spiral pattern within a space formed between a concentric inner cylinder and an outer cylinder. Heat exchange occurs between a first fluid flowing through the first flow path and a second fluid flowing through the second flow path via a heat transfer body. The heat transfer body is characterized in that it is spirally arranged and has a roughly triangular cross-sectional shape in an axial sectional view. The space is divided into the first flow path and the second flow path by the heat transfer body, and the heat exchange occurs via the heat transfer body.

[0021] The heat exchanger of the present invention has a spirally arranged heat transfer body disposed in a space formed between a concentric inner cylinder and an outer cylinder. The space is divided into a first flow path and a second flow path by the heat transfer body. Heat exchange occurs between a first fluid flowing through the first flow path and a second fluid flowing through the second flow path via the heat transfer body. The inner cylinder, the outer cylinder, and the heat transfer tube are assembled in a manner that allows them to be separated into a side where the outer cylinder is located and a side where the inner cylinder is located. In the state of being separated into a side where the outer cylinder is located and a side where the inner cylinder is located, the flow path forming surface of the first flow path is separated into a side where the outer cylinder is located and a side where the inner cylinder is located. Furthermore, all surfaces of the flow path forming surface of the first flow path are directly exposed without being obstructed by other parts when viewed from a radial direction orthogonal to the axial direction.

[0022] It is preferable for at least one of the inner and outer cylinders to be circular in axial cross-sectional view. This allows for the generation of a spiral convection flow in the first fluid flowing through the heat transfer medium, which has a generally triangular cross-sectional shape, and the first flow path defined by the inner or outer cylinder.

[0023] Furthermore, it is also appropriate that the ratio (λ / μ) of the maximum flow path width (λ) of the first flow path in the radial direction to the minimum flow path width (μ) of the first flow path is 2 or more (2 < λ / μ < ∞). Thus, compared to axial flow toward the inner or outer cylinder, the flow toward the spiral direction can be increased, and the overall flow direction of the first fluid as a whole can be spiral.

[0024] Furthermore, the present invention can be implemented with the following structure: the heat transfer body is fixed to either the side where the outer cylinder is located or the side where the inner cylinder is located, but not fixed to either the side where the outer cylinder is located or the side where the inner cylinder is located, and has a three-dimensional shape portion having at least one bent portion that can form a space for fluid flow on both its inner and outer surfaces, wherein the outer angle of all the bent portions appearing on the flow path constituting the first flow path is 90 degrees or more.

[0025] Furthermore, the present invention can be implemented with the following structure: the first flow path and the second flow path based on the heat transfer body do not have horizontal portions where the first fluid and the second fluid may accumulate.

[0026] In addition, the present invention can be implemented in the following structure: the first flow path and the second flow path are respectively spirally wound, and there is no gap between the axially adjacent wound portions or there is a gap of less than 4 mm in the radial direction.

[0027] In addition, the present invention can be implemented with the following structure: the cross-sectional shape of the first flow path and the second flow path in the axial sectional view is approximately triangular with a vertex angle θ of 30 degrees or more and 125 degrees or less.

[0028] In addition, the present invention can be implemented in the following structure: the side where the inner cylinder is located and the side where the outer cylinder is located are assembled such that they can be separated by moving along the axial direction without rotating, and the heat transfer body does not interfere with other parts when moving along the axial direction.

[0029] In addition, the present invention can be implemented with the following structure: the cross-sectional shape of the first flow path and the second flow path in the axial sectional view is a general triangle having two inclined planes, a bottom surface and a top surface, wherein the axial length (a) of the top surface is shorter than the axial length (b) of the inclined planes.

[0030] Furthermore, the present invention can be implemented in a structure in which the top of at least one of the first flow path and the second flow path has a length (a) in the axial direction, and the cross-sectional area of ​​the flow path is increased compared to the case where the top is a vertex without a length (a) in the axial direction.

[0031] In addition, the present invention can be implemented with a structure in which the space formed between the concentrically arranged inner cylinder and the outer cylinder has a plurality of concentric spaces.

[0032] Furthermore, the present invention can be implemented with the following structure: at least one of the flow path for the first fluid to flow, including the first flow path, and the flow path for the second fluid to flow, including the second flow path, is coated with a corrosion-resistant material. Preferably, the corrosion-resistant material coating is one of glass lining, fluoropolymer coating, or ceramic coating.

[0033] The effects of the invention

[0034] The present invention provides a heat exchanger having a structure suitable for suppressing the fluid being processed and generating gas retention in the heat transfer section.

[0035] The present invention provides a heat exchanger with good cleanability.

[0036] The present invention provides a heat exchanger with a structure that is easily decomposed.

[0037] The present invention can provide a heat exchanger that can also be coated or lined.

[0038] More specifically, processes in chemical and food manufacturing, as well as in the production of colorants or inkjet printers, often involve rapid cooling or high-speed heating. The materials being processed—the fluids—are typically high-viscosity liquids, suspensions containing particulates, and often contain adhering substances. Furthermore, when using heat exchangers for heating operations accompanied by evaporation, the thermal conductivity drops to a low order of magnitude, similar to the single-phase flow of the generated gas, when gas stagnation occurs. This phenomenon, known as evaporation, occurs because the liquid film flowing along the heat transfer surface evaporates and disappears, allowing the gas phase to directly contact the heat transfer surface. Additionally, heat exchangers need to be reliably scaled up; high performance is a given, but even large-scale operations require computational considerations.

[0039] To address these issues, a heat exchanger is provided that, even if the flow rate of the fluid being processed is increased by re-examining the relationship between the flow rate and pressure loss, the pressure loss will not be excessive. In particular, it is highly effective and produces less fouling or adhesion when the fluid being processed is a high-viscosity liquid or a easily settling suspension.

[0040] In addition, by making the cross-sectional shape of the heat transfer body roughly triangular, there is no liquid accumulation or gas accumulation, and the heat transfer area can be increased. The design also has a degree of freedom to choose a roughly triangular shape for the cross-section of the heat transfer body according to the physical properties of the fluid being processed.

[0041] In addition, the amount of fluid being processed is small, and it is easy to rapidly heat or cool it in emergencies. At the same time, the amount of heat medium or refrigerant is also small. Therefore, it is possible to achieve miniaturization, high performance, and easy control of the equipment.

[0042] Because of its very simple structure, this structure is easy to disassemble or assemble, and can be coated or lined with corrosion-resistant materials. Attached Figure Description

[0043] Figure 1 This is an axial sectional view of the heat exchanger according to the first embodiment of the present invention.

[0044] Figure 2 This is an enlarged sectional view of the main part showing the inner and outer cylinders separated.

[0045] Figure 3 This is an axial sectional view of the heat exchanger according to the second embodiment of the present invention.

[0046] Figure 4(A) to (F) are axial sectional views of the main parts of a modified example of the heat exchanger according to an embodiment of the present invention. Detailed Implementation

[0047] The heat exchanger according to an embodiment of the present invention will now be described with reference to the accompanying drawings. Furthermore, Figure 2 , Figure 4 The center lines recorded in (A) to (F) represent the axial direction.

[0048] (The fluid that undergoes heat exchange)

[0049] In this embodiment, the fluid intended for heat exchange will be described as the first fluid F1. Heat exchange involves the exchange of thermal energy between two fluids, so a master-slave distinction is not necessary; however, it is often performed for the purpose of heating or cooling a specific fluid. Therefore, in this embodiment, the fluid to be heated or cooled will be described as the first fluid F1. The fluid that exchanges heat with the first fluid F1 will be described as the second fluid F2. Furthermore, another fluid that exchanges heat with the first fluid F1 will be described as the third fluid F3.

[0050] The first fluid F1 can be any fluid such as gas, liquid, suspension, or highly viscous liquid. The second fluid F2 and the third fluid F3 can be heat transfer media such as water vapor, warm water, cold water, or nitrogen. However, the types of these fluids should not be fixed; the first fluid F1 can be used as the heat transfer media, or the second fluid F2 and the third fluid F3 can be used as fluids for heat exchange.

[0051] (Summary of the first embodiment)

[0052] Figure 1 The heat exchanger of the first embodiment shown has an inner cylinder 10 and an outer cylinder 20 arranged concentrically, and may, if necessary, have a third cylinder 30 arranged concentrically inside the inner cylinder 10.

[0053] A heat transfer element 41 is arranged in a spiral manner on the inner circumferential surface of the outer cylinder 20.

[0054] The space between the inner cylinder 10 and the outer cylinder 20 is divided into two spaces by the heat transfer body 41. The inner side (inner side in the radial direction) of the heat transfer body 41 in the two divided spaces forms the first flow path 11, which is the flow path of the first fluid F1, and the outer side (outer side in the radial direction) of the heat transfer body 41 in the two divided spaces forms the second flow path 21, which is the flow path of the second fluid F2.

[0055] The heat transfer element 41 is fixed to the inner circumferential surface of the outer cylinder 20 by welding or other means to maintain airtightness and liquid tightness. This divides the space between the inner cylinder 10 and the outer cylinder 20 into a first flow path 11 and a second flow path 21, so that the first fluid F1 and the second fluid F2 do not mix. The first flow path 11 and the second flow path 21 form a spiral flow path. Heat exchange occurs between the first fluid F1 and the second fluid F2 through the heat transfer element 41.

[0056] The inner cylinder 10 and the outer cylinder 20 are assembled in a separable manner, such as... Figure 2 As shown, in the separated state, the heat transfer element 41 and the outer cylinder 20 are separated from the inner cylinder 10. In this separated state, the flow path forming surface of the first flow path 11 is defined as the inner cylinder 10 side and the outer cylinder 20 side.

[0057] In this example, the space between the inner cylinder 10 and the third cylinder 30 forms a third flow path 31 for the third fluid F3, through which heat exchange occurs between the first fluid F1 and the third fluid F3. Furthermore, since the flow path body 42 is fixed to the outer circumferential surface of the third cylinder 30 in a spiral shape, the third flow path 31 also becomes a spirally surrounding flow path.

[0058] (Fixing and separating the cylinder)

[0059] The inner cylinder 10, outer cylinder 20, and third cylinder 30 are fixed at the flange 40 at the upper end of the cylinders in a separable manner. In this example, the two flanges 40 overlap and sandwich the sealing member, and are assembled separately using a detachable fixing member (not shown) such as bolts, thus becoming a single unit. The upper ends of the inner cylinder 10 and the third cylinder 30 (detachable as needed) are fixed to the upper flange 40, and the upper end of the outer cylinder 20 (detachable as needed) is fixed to the lower flange 40. By separating the upper and lower flanges 40, the inner cylinder 10 and the outer cylinder 20 can be separated. Alternatively, the inner cylinder 10 and the third cylinder 30 can also be separated by making at least one of them detachable from the upper flange 40.

[0060] As described above, the heat transfer element 41 is fixed to the inner circumferential surface of the outer cylinder 20 by welding or the like. Therefore, when the heat exchanger is disassembled by detaching the flange portion 40, the heat exchanger is separated into the outer cylinder 20 with the heat transfer element 41 fixed to its inner circumferential surface, the inner cylinder 10, and the third cylinder 30 with the flow path 42 on its outer circumferential surface. At this time, since there is no object interfering with the heat transfer element 41, the outer cylinder 20 with the heat transfer element 41 and the lower flange portion 40 can be pulled downwards as shown in the figure.

[0061] (Regarding heat transfer element 41)

[0062] The heat transfer element 41 travels axially between the inner cylinder 10 and the outer cylinder 20 in a spiral shape. Figure 1 and Figure 2 As shown, in the axial sectional view, the cross-sectional shape is approximately triangular. In this embodiment, the heat transfer element 41 is fixed to the inner circumferential surface of the outer cylinder 20 by welding or the like.

[0063] Regarding the apex angle θ of the approximate triangle in the axial cross-sectional view of the heat transfer body 41, as the apex angle θ increases, the cross-sectional area (flow path area) of the first flow path 11 and the second flow path 21 increases, but the number of rotations of the spiral per unit axial length of the inner cylinder 10 and the outer cylinder 20 decreases. Furthermore, as the apex angle θ moves away from 90 degrees, the narrower portions of the first flow path 11 and the second flow path 21 increase, thus increasing the likelihood of fluid blockage. Considering these factors, an apex angle θ of 30 degrees or more and 125 degrees or less is more appropriate.

[0064] In addition, relative to the vertex angle θ of the above approximate triangle, the exterior angle (360-θ) should be above 90 degrees, above 235 degrees and below 330 degrees.

[0065] In a mathematical sense, the two hypotenuses of a triangle intersect at the vertex. However, in industrial production contexts such as metal sheet processing, the triangle typically forms an arc at the vertex or a cross-sectional shape with length in the axial direction. Therefore, the term "approximate triangle" should be understood to encompass not only the mathematical meaning of a triangle but also the shape inherent in these industrial production processes. Thus, the vertex angle θ of an approximate triangle should be understood as representing the intersection of the two hypotenuses and the intersection of their extensions. Furthermore, in the case of a cross-sectional shape with length in the axial direction, as this axial length increases, the likelihood of the first fluid F1 becoming blocked between the heat transfer body 41 and the outer circumference of the inner cylinder 10 increases. Therefore, it is more appropriate for this axial length to be shorter than the axial length of one hypotenuse.

[0066] Next, since heat exchange occurs between the first fluid F1 and the second fluid F2 via the heat transfer element 41, the thickness t of the heat transfer element 41 is preferably 0.2 mm to 3 mm, more preferably 0.5 mm to 2 mm, considering the efficiency of heat exchange. The thicknesses of the inner cylinder 10, outer cylinder 20, and third cylinder 30 can also be the same. However, they can also be modified to ensure the strength of the inner cylinder 10, outer cylinder 20, and third cylinder 30 as structural members, and are not limited thereto.

[0067] The heat transfer element 41 can also be described as being composed of a three-dimensional shape portion 43 having at least one bent portion (in addition to a straight line bent at an angle, a curved portion including an arc-shaped portion is also referred to as a bent portion). The three-dimensional shape portion 43 has the following shape: having at least one bent portion, it can form spaces (first flow path 11 and second flow path 21) for fluid flow on both its inner and outer surface sides. Specifically, the three-dimensional shape portion 43 is a strip-shaped body having the shape of dividing a polygonal prism or cylinder along its axial direction. In this example, the three-dimensional shape portion 43 is a strip-shaped body having the shape of dividing a quadrangular prism along its axial direction on the diagonal of a quadrilateral cross-section. The three-dimensional shape portion 43 is wound around the inner circumferential surface of the outer cylinder 20, and its upper and lower end edges 46 are fixed to the inner circumferential surface of the outer cylinder 20. It is more appropriate for the external angle θo formed by the three-dimensional shape portion 43 of the upper and lower end edges 46 and the inner circumferential surface of the outer cylinder 20 to be 90 degrees or more, and more preferably 105 ≤ θo ≤ 160. Furthermore, when the three-dimensional shape portion 43 of the end edge 46 is bent, it is the angle formed by its tangent and the inner circumferential surface of the outer cylinder 20.

[0068] In addition, the outer angle of the bent portion of the three-dimensional shape part 43 refers to the outer angle (360-θ) relative to the vertex angle θ of the above-mentioned approximate triangle and the outer angle θo formed by the three-dimensional shape part 43 of the upper and lower end edges 46 and the inner circumferential surface of the outer cylinder 20.

[0069] (Regarding the first path 11)

[0070] The first flow path 11 forms a flow path with a roughly triangular cross-sectional shape. It is the flow path of the first fluid F1, which is the main object of heat exchange, in the space between the heat transfer body 41 that spirals around the inner circumference of the outer cylinder 20 and the outer circumference of the inner cylinder 10.

[0071] The first flow path 11 is defined by the following: a bottom surface 12 formed by the outer peripheral surface of the inner cylinder 10; two inclined surfaces, a first inclined surface 13 and a second inclined surface 14; and a top 15 between the first inclined surface 13 and the second inclined surface 14. The top 15 is formed by the inner peripheral surface of the outer cylinder 20, and this part becomes the axial space between the spiral portions of the heat transfer element 41. In addition, if the heat transfer element 41 is made into a denser spiral shape in order to avoid creating this axial space, the top 15 becomes a point-like vertex with no length in the axial cross-sectional shape.

[0072] In this embodiment, the inner cylinder 10 is a circular cylindrical body in the axial sectional view, and its outer circumferential surface is a smooth, cylindrical outer circumferential surface. Similarly, in this example, the outer cylinder 20 is also a circular cylindrical body in the axial sectional view, and its inner circumferential surface is a smooth, cylindrical cylindrical surface.

[0073] If the axial length (a) of the top 15 is increased, the cross-sectional area (flow path area) of the first flow path 11 can be increased. However, even if it is increased, the area of ​​the heat transfer body 41, which is directly related to heat exchange, remains unchanged, so the overall heat exchange rate may be reduced. Therefore, it is preferable that the axial length (a) of the top 15 is shorter than the axial length (b) of the inclined surfaces 13 and 14.

[0074] In the axial cross-sectional view, it is preferable that the first inclined surface 13 and the second inclined surface 14 are straight, but they can also be curved, such as bow-shaped. However, it is preferable that the flow paths (first flow path 11 and second flow path 21) with the above-mentioned cross-sectional shape be approximately triangular, as this shape eliminates the possibility of accumulation of the processed fluids or gases, such as the first fluid F1 and the second fluid F2. Unless there is a particular purpose, it is best to avoid providing, for example, flat horizontal portions or recesses in a part of the flow path.

[0075] Furthermore, in this example, such as Figure 2 As shown, a gap (μ) is provided on the base side of the first flow path 11, which has a generally triangular cross-section in the axial direction. In other words, a space is provided between the end of the inner circumference side of the first inclined surface 13 and the bottom surface 12, and a space is provided between the end of the inner circumference side of the second inclined surface 14 and the bottom surface 12. This gap (μ) may be omitted; if it is provided, a gap (μ) of 4 mm or less is preferable. Furthermore, in other words, a gap (μ) is provided between the axially adjacent surrounding portions of the spirally wound first flow path 11, that is, between the axially adjacent generally triangular cross-sectional shapes. This gap (μ) may also be omitted; if it is provided, a gap (μ) of 4 mm or less in the radial direction is suitable.

[0076] By setting this gap (μ), the separation of the outer cylinder 20 and the inner cylinder 10 can proceed smoothly in the case of a decomposition heat exchanger. However, if the gap is too large, the first fluid F1 will not flow in a spiral shape, and the amount of fluid flowing through the axial short circuit will increase, which may reduce the efficiency of heat exchange.

[0077] The gap (μ) can be understood as the maximum flow path width (μ) of the first flow path 11 in the radial direction, and the length between the top 15 and the bottom 18 of the first flow path 11 defines the maximum flow path width (λ) of the first flow path 11 in the radial direction. Here, it is more appropriate for the ratio (λ / μ) of the maximum flow path width (λ) to the minimum flow path width (μ) of the first flow path 11 to be 2 or more, preferably 10 or more. In the absence of the aforementioned gap μ (in other words, when the heat transfer body 41 is in contact with the inner cylinder 10), μ = 0, λ / μ = ∞.

[0078] Furthermore, the description of the heat transfer element 41, such as the apex angle θ of the approximate triangle in the axial sectional view, also applies to the first flow path 11.

[0079] Assume that various fluids, such as gas, liquid, suspension, and highly viscous liquid, flow through the first flow path 11 as the first fluid F1. Depending on the type of fluid, highly viscous substances (highly viscous materials) or easily settling suspensions may adhere to the first flow path 11. In this embodiment, the first flow path 11 has an approximately triangular axial cross-section and does not have any narrow sections that would prevent passage, thus creating a structure capable of suppressing the adhesion of highly viscous substances (highly viscous materials) and easily settling suspensions.

[0080] In addition, when disassembling and cleaning, as long as the inner cylinder 10 and the outer cylinder 20 are separated, the outer circumferential surface of the inner cylinder 10 will naturally be exposed, and the entire heat transfer body 41 with an axial cross section of approximately triangular shape will also be exposed together with the inner circumferential surface of the outer cylinder 20.

[0081] In other words, the flow path forming surface of the first flow path 11 is defined as the inner circumferential surface of the outer cylinder 20 and the surface inside the heat transfer body 41 in the radial direction on the outer cylinder 20 side, and as the outer circumferential surface of the inner cylinder 10 on the inner cylinder 10 side. All these surfaces are configured to be directly exposed without being obstructed by other parts when viewed from a radial direction orthogonal to the axial direction.

[0082] Therefore, it is possible to clean every corner of the first flow path 11, and it is also easy to confirm the state when cleaning is completed. In contrast, in the heat exchanger described in Patent Document 1 above, the space between the circular cross-section spiral heat transfer tube and the inner circumferential surface of the outer cylinder or the outer circumferential surface of the inner cylinder must become narrow. Even if the inner cylinder and the outer cylinder are separated, if the spiral heat transfer tube is not separated, when viewed from the radial direction, the back half of the spiral heat transfer tube is obscured by the front half and is not directly exposed. As a result, it is difficult to clean every corner, and it is not easy to confirm the cleaning status.

[0083] The material of each surface of the first fluid F1, such as the first flow path 11, can be selected from metals or the like, depending on the type of the first fluid F1. Furthermore, it is preferable to coat its surface with a corrosion-resistant material. Examples of corrosion-resistant coatings include glass enamel, fluoropolymer coatings, and ceramic coatings. In this case, as long as the heat transfer element 41 is fixed to the inner circumferential surface of the outer cylinder 20 by welding or the like, and the same coating is applied to the outer circumferential surface of the inner cylinder 10 before inserting the inner cylinder 10 into the outer cylinder 20 for assembly, the entire inner surface of the first flow path 11, i.e., the entire flow path constituting surface of the first flow path 11, can be reliably coated.

[0084] (Regarding the second flow path 21)

[0085] The space outside the heat transfer body 41 in the radial direction (in other words, the space between the heat transfer body 41 and the inner circumferential surface of the outer cylinder 20) forms a second flow path 21 with an approximately triangular axial cross-sectional shape. This second flow path 21 is defined by: a bottom surface 22 formed by the inner circumferential surface of the outer cylinder 20; two inclined surfaces, a first inclined surface 23 and a second inclined surface 24; and a top 25 between the first inclined surface 23 and the second inclined surface 24. The top 25 can be a point-like vertex with no length in the axial cross-sectional shape, or it can be a straight or curved top with length in the axial cross-sectional shape. When the top 25 is set to be a straight or curved top with length in the axial cross-sectional shape, it is preferable that the axial length (a) of the top 25 is shorter than the axial length (b) of the inclined surfaces 23 and 24. It is more appropriate for the first inclined surface 23 and the second inclined surface 24 to be straight in the axial cross-sectional view, but they can also be curved, such as bow-shaped curves.

[0086] Furthermore, the description of the heat transfer element 41, such as the apex angle θ of the approximate triangle in the axial sectional view, also applies to the second flow path 21.

[0087] Unlike the first flow path 11, the second flow path 21 is a closed space in the axial cross-sectional view. Therefore, it remains closed by separating only the inner cylinder 10 and the outer cylinder 20. However, the second flow path 21 usually allows hot media such as water vapor, warm water, cold water, and nitrogen to pass through as the second fluid F2. Therefore, unlike the first flow path 11, the possibility of fluids adhering is small.

[0088] (Regarding the third flow path 31)

[0089] A spirally extending plate-shaped flow path body 42 is fixed to the outer circumferential surface of the third cylinder 30 by welding or the like, thereby making the third flow path 31 a spiral space. The circumferential direction of the third flow path 31 can be the same as or different from the circumferential direction of the first flow path 11 and the second flow path 21 (e.g., clockwise and counterclockwise).

[0090] As long as the inner cylinder 10 and the third cylinder 30 are not separated, the third flow path 31 remains closed. However, since the third flow path 31 usually allows hot media such as water vapor, warm water, cold water, and nitrogen to pass through as the third fluid F3, it is less likely to have fluids adhering to it than the first flow path 11.

[0091] (Regarding inflows and outflows)

[0092] The inner cylinder 10, outer cylinder 20, and third cylinder 30 each have a dome-shaped bottom 18, bottom 28, and bottom 34, respectively. The space between the bottom 18 of the inner cylinder 10 and the bottom 28 of the outer cylinder 20 is connected to the lower part of the spiral first flow path 11, and the space between the bottom 18 of the inner cylinder 10 and the bottom of the third cylinder 30 is connected to the lower part of the spiral third flow path 31.

[0093] Figure 1 The lower end of the first flow path 11 is connected to the external flow path via the inlet portion 16. In this example, the inlet portion 16 is configured to have a connecting pipe installed in a through hole opening into the bottom 28 of the outer cylinder 20. The upper end of the first flow path 11 is connected to the external flow path via the outlet portion 17. In this example, the outlet portion 17 is configured to have a connecting pipe installed in a through hole opening into the flange portion 40. The first fluid F1 flows into the spiral-shaped first flow path 11 from the inlet portion 16, rises while spiraling, and flows out to the outside from the outlet portion 17.

[0094] Next, the upper end of the second flow path 21 is connected to the external flow path via the inlet 26. In this example, the inlet 26 is configured to have a connecting pipe installed in the through hole opening into the outer cylinder 20. The lower end of the second flow path 21 is connected to the external flow path via the outlet 27. In this example, the outlet 27 is configured to have a connecting pipe installed in the through hole opening into the outer cylinder 20. The second fluid F2 flows from the inlet 26 into the spiral-shaped second flow path 21, descends in a spiral shape, and flows out from the outlet 27 to the outside.

[0095] Next, the upper end of the third flow path 31 is connected to the external flow path via the inlet 32. In this example, the inlet 32 ​​is configured to have a connecting pipe installed in a through hole opening into the flange 40. The lower end of the third flow path 31 is connected to the external flow path via the outlet 33. In this example, the outlet 33 is configured to have a connecting pipe installed in a through hole opening into the center of the bottom 34, the connecting pipe extending axially within the cylindrical space inside the third cylinder 30 to a height approximately the same as the outlet 17 of the first flow path 11 and the inlet 26 of the second flow path 21. The third fluid F3 flows from the inlet 32 ​​into the spiral-shaped third flow path 31, descends in a spiral shape, and flows outward from the outlet 33.

[0096] In addition, the inflow and outflow sections of each flow path can also be implemented in reverse.

[0097] The materials for each surface along the passage paths of the second fluid F2 and the third fluid F3, such as the second flow path 21 and the third flow path 31, can be selected from metals or the like, depending on the types of the second fluid F2 and the third fluid F3. However, it is also preferable to pre-coat the surfaces with a corrosion-resistant material. Examples of corrosion-resistant coatings include glass enamel, fluoropolymer coatings, and ceramic coatings.

[0098] (Second Implementation)

[0099] Figure 3This is an axial sectional view of the heat exchanger according to the second embodiment. The heat exchanger of this embodiment differs from that of the heat exchanger of the first embodiment in that the third cylinder 30 is disposed outside the outer tube 20. In the following description, the differences will be the focus; for matters not described herein, the description of the first embodiment above applies.

[0100] In the heat exchanger of this second embodiment, the inner cylinder 10, outer cylinder 20, and third cylinder 30 are arranged concentrically towards the outer side in the radial direction. The upper end of the inner cylinder 10 and the heat transfer element 41 (which can be removed as needed) is mounted on the upper flange 40, and the upper end of the outer cylinder 20 (which can be removed as needed) is mounted on the lower flange 40. The two flanges 40 can be joined together vertically. The upper end of the third cylinder 30 is joined to the outer peripheral surface near the upper end of the outer cylinder 20 by welding or the like, and the lower end of the third cylinder 30 is joined to the outer peripheral surface of the bottom 28 of the outer cylinder 20 by welding or the like.

[0101] The space on the inner surface of the heat transfer body 41, in other words, the space between the heat transfer body 41 and the inner cylinder 10, becomes the second flow path 21. The space on the outer surface of the heat transfer body 41, in other words, the space between the heat transfer body 41 and the outer cylinder 20, becomes the first flow path 11. The space between the outer cylinder 20 and the third cylinder 30 becomes the third flow path 31.

[0102] The heat transfer element 41 has a generally triangular cross-sectional shape in the axial cross-section, and the three-dimensional parts 43 are connected to each other via flat cylindrical parts 44. In other words, as a whole, the heat transfer element 41 is also cylindrical, and the shape of the cylindrical wall is a concave-convex shape with three-dimensional parts 43 and flat parts 44, which are spirally wrapped around each other and travel along the axial direction.

[0103] (Regarding each flow path)

[0104] The first flow path 11 is defined by the bottom surface 12 formed by the inner circumferential surface of the outer cylinder 20, the two inclined surfaces 13 and 14, and the top 15 between the first inclined surface 13 and 14. The top 15 is formed by a flat portion 44, which is a linear top with length in the axial cross-sectional shape, but it can also be a point-like vertex without length.

[0105] The second flow path 21 is defined by a bottom surface 22, two inclined surfaces 23 and 24, and a top surface 25 between the first inclined surface 23 and the second inclined surface 24. The bottom surface 22 is formed by the outer peripheral surface of the inner cylinder 10. The top surface 25 can be a point-like vertex with no length in the axial cross-sectional shape, or it can be a line-like top with length.

[0106] A spirally extending plate-shaped flow path body 42 is fixed to the inner circumferential surface of the third cylinder 30 by welding or the like, thereby making the third flow path 31 a spiral space. The circumferential direction of the third flow path 31 can be the same as or different from the circumferential direction of the first flow path 11 and the second flow path 21 (e.g., clockwise and counterclockwise).

[0107] (Regarding inflows and outflows)

[0108] The outer cylinder 20, the third cylinder 30 and the heat transfer body 41 have dome-shaped bottoms 28, 34 and 45 respectively, but the inner cylinder 10 does not have a dome-shaped bottom. Its bottom end is fixed to the inner surface of the bottom 45 of the heat transfer body 41 by welding or the like.

[0109] The lower end of the first flow path 11 is connected to the external flow path via the inlet 16. In this example, the inlet 16 is implemented as a structure in which a connecting pipe is installed in a through hole that opens into the bottom 28 of the outer cylinder 20.

[0110] The upper end of the first flow path 11 is connected to an external flow path via the outlet 17. In this example, the outlet 17 is configured to have a connecting pipe installed in a through hole opening in the flange 40. The first fluid F1 flows into the spiral first flow path 11 from the inlet 16 and rises spirally, then flows out from the outlet 17 to the outside.

[0111] Next, the upper end of the second flow path 21 is connected to the external flow path via the inlet 26. In this example, the inlet 26 is configured to have an L-shaped bent connecting pipe installed in a through hole opening into the inner wall surface near the upper end of the inner cylinder 10. The lower end of the second flow path 21 is connected to the external flow path via the outlet 27. In this example, the outlet 27 is configured to have an L-shaped bent connecting pipe installed in a through hole opening into the inner wall surface near the lower end of the inner cylinder 10, the bent connecting pipe extending inside the cylindrical space inside the inner cylinder 10 until its axial position is approximately the same height as the inlet 26.

[0112] The second fluid F2 flows into the spiral-shaped second flow path 21 from the inlet 26, descends while spiraling, and flows out to the outside from the outlet 27.

[0113] Next, the upper end of the third flow path 31 is connected to the external flow path via the inlet 32. In this example, the inlet 32 ​​is configured such that a connecting pipe is installed in a through hole opening near the upper end of the outer peripheral surface of the third cylinder 30. The lower end of the third flow path 31 is connected to the external flow path via the outlet 33. In this example, the outlet 33 is configured such that a connecting pipe is installed in a through hole opening near the lower end of the bottom 34 of the third cylinder 30. The third fluid F3 flows from the inlet 32 ​​into the spiral-shaped third flow path 31, descends in a spiral shape, and flows out from the outlet 33 to the outside.

[0114] In addition, the inflow and outflow sections of each flow path can also be implemented in reverse.

[0115] (Separation of the cylinder)

[0116] When the heat exchanger is disassembled by releasing the detachable connecting members (not shown) such as bolts on the upper and lower flanges 40, it can be separated into an outer cylinder 20 with the third cylinder 30 attached, an inner cylinder 10, and a heat transfer element 41. The outer cylinder 20 with the third cylinder 30 attached and the lower flange 40 can be pulled downwards as shown in the figure. As a result, the first flow path 11 is separated into two states, inner and outer, with the flow path forming surface of the first flow path 11 separated into an inner cylinder 10 side and an outer cylinder 20 side. The flow path forming surface of the first flow path 11 is defined as the inner circumferential surface of the outer cylinder 20 on the outer cylinder 20 side and the radially outer surface of the heat transfer element 41 on the inner cylinder 10 side. All these surfaces are configured to be directly exposed without being obstructed by other parts when viewed from a radial direction orthogonal to the axial direction. Therefore, as in the first embodiment, the first flow path 11 becomes extremely easy to clean.

[0117] In the first embodiment, the outer angle θo is the angle formed by the three-dimensional shape portion 43 and the outer cylinder 20. In this embodiment, the outer angle θo is the angle formed by the three-dimensional shape portion 43 and the flat portion 44. In either case, since the outer angle θo is an obtuse angle of 90 degrees or more, in the separated state, the open portion is without any narrow parts. Therefore, cleaning the first flow path 11 is extremely simple, and the cleaning status is easy to confirm.

[0118] (about Figure 4 )

[0119] In addition to the embodiments described above, the present invention can be implemented with various modifications. (See also...) Figure 4 Explain these examples of changes.

[0120] Heat transfer element 41 can be as Figure 4 As shown in (A), it is disposed on the outer peripheral surface of the inner cylinder 10, or as shown in [A], it can also be disposed on the outer peripheral surface of the inner cylinder 10. Figure 4 (B) is arranged on the inner circumferential surface of the outer cylinder 20. Alternatively, the heat transfer element 41 may not have the flat portion 44 and the three-dimensional portion 43 may be fixed on the circumferential surface of the cylinder, or it may have both the three-dimensional portion 43 and the flat portion 44 and be cylindrical in shape.

[0121] like Figure 4 As shown in (A), the radial width S of the space between the inner cylinder 10 and the outer cylinder 20 is preferably 4 mm to 75 mm, and more preferably 10 mm to 50 mm.

[0122] Should Figure 4(B) can also be considered a variation of the second embodiment. In the second embodiment, the top 25 of the heat transfer body 41 faces the outer peripheral surface of the inner cylinder 10. In contrast, in this variation, the top 25 of the heat transfer body 41 faces the inner peripheral surface of the outer cylinder 20. In this example, a gap (d) is provided between the outer peripheral surface of the flat portion 44 of the heat transfer body 41 and the inner peripheral surface of the outer cylinder 20. In other words, a space is provided between the end edge 46 of the three-dimensional shape portion 43 and the inner peripheral surface of the outer cylinder 20. This gap (d) can also be omitted, but it is more appropriate for the gap (d) to be 3 mm or less. In other words, a gap (d) is provided between the axially adjacent surrounding portions of the spiral-shaped second flow path, that is, between the axially adjacent approximately triangular cross-sectional shapes and approximately triangular cross-sectional shapes. This gap (d) can also be omitted, and when a gap (d) is provided, it is suitable to set it to 3 mm or less in the radial direction. By setting this gap (d), the second flow path 21 can be enlarged. Conversely, if the gap is too large, the second fluid F2 will not flow in a spiral shape but will instead pass through a short circuit in the axial direction, resulting in a larger amount of fluid flowing, which may reduce the efficiency of heat exchange.

[0123] Next, the third tube 30 can be as follows Figure 4 As shown in (C), it is configured and fixed to the outside of the outer cylinder 20, or as shown in (C). Figure 4 (D) The configuration is fixed inside the inner cylinder 10. Alternatively, the third cylinder 30 can be omitted and the first flow path 11 and the second flow path 21 can be used instead.

[0124] like Figure 4 As shown in (E), two sets of heat transfer bodies 41 can also be used. In this case, it can be represented that one heat transfer body 41 is fixed to the outer circumferential surface of the inner cylinder 10 and the other heat transfer body 41 is fixed to the inner circumferential surface of the outer cylinder 20. If the space between the two sets of heat transfer bodies 41, 41 forms a first flow path 11 for the flow of the first fluid F1, then when the inner cylinder 10 and the outer cylinder 20 are separated, the first flow path 11 becomes a separate state of inner and outer, and the flow path forming surface of the first flow path 11 is defined as the inner cylinder 10 side and the outer cylinder 20 side. The flow path forming surface of the first flow path 11 is defined as the surface inside the heat transfer body 41 in the radial direction on the outer cylinder 10 side, and the surface outside the heat transfer tube 41 in the radial direction on the inner cylinder 20 side. These surfaces are configured to be directly exposed without being obstructed by other parts when viewed from a radial direction orthogonal to the axial direction.

[0125] The space between one heat transfer element 41 and the inner cylinder 10, and the space between the other heat transfer element 41 and the outer cylinder 20, constitute the second flow path and the third flow path. Additionally, in Figure 4 In (E), the two sets of heat transfer bodies 41 are arranged with the tops of the roughly triangular axial cross sections facing each other, but the spacing between them can also be staggered, etc.

[0126] Figure 4 (F) is a variation of the second embodiment, in which a fourth cylinder 50 can be concentrically arranged further inside the inner cylinder 10, and a heat transfer element 41 can be arranged in the space between the inner cylinder 10 and the fourth cylinder 50, thus allowing for the arrangement of multiple heat transfer elements 41. In the concentrically arranged inner cylinder 10 and fourth cylinder 50, from the perspective of their radial inward / outward relationship, the inner cylinder 10 is positioned further outward than the fourth cylinder 50, and the fourth cylinder 50 is positioned further inward than the inner cylinder 10. Therefore, the inner cylinder 10 corresponds to the outer cylinder 20, and the fourth cylinder 50 corresponds to the inner cylinder 10. Thus, Figure 4 (F) is a structure in which two concentric spaces are formed between the inner cylinder 10 and the outer cylinder 20, and multiple spaces formed between the concentric inner cylinder and the outer cylinder are concentrically arranged.

[0127] In any of the above examples, the inner cylinder 10 side and the outer cylinder 20 side are designed to be assembled in a manner that allows them to be separated solely by axial (vertical) movement without rotation, and the heat transfer element 41 is sized to not interfere with other parts when moving axially (vertically). Specifically, in the case of a cylindrical inner cylinder 10 and outer cylinder 20 with a fixed radius, if the heat transfer element 41 is fixed to the inner cylinder 10 side, the maximum outer diameter of the heat transfer element 41 is set to be smaller than the inner diameter of the outer cylinder 20. Furthermore, when the heat transfer element 41 is fixed to the outer cylinder 20 side, the minimum inner diameter of the heat transfer element 41 is set to be larger than the outer diameter of the inner cylinder 20. Additionally, the present invention can also be implemented in which the inner cylinder 10 and the outer cylinder 20 are approximately conical cylinders whose radii vary with axial orientation. In this case, if the inner cylinder 10 can be separated from the outer cylinder 20 by moving the inner cylinder 10 upwards as shown in the figure, then with the heat transfer element 41 fixed to the inner cylinder 10 side, the maximum outer diameter of the heat transfer element 41 in each section orthogonal to the axial direction is set to be smaller than the inner diameter of the outer cylinder 20 above that section. Conversely, if the heat transfer element 41 is fixed to the outer cylinder 20 side, the minimum inner diameter of the heat transfer element 41 in each section orthogonal to the axial direction is set to be larger than the outer diameter of the inner cylinder 20 above that section.

[0128] Explanation of reference numerals in the attached figures

[0129] F1 First Fluid

[0130] F2 Second Fluid

[0131] F3 Third Fluid

[0132] 10 Inner cylinder

[0133] 11 First flow path

[0134] 12 Bottom

[0135] 13 First inclined plane

[0136] 14 second slope

[0137] 15 Top

[0138] 16. Inflow section

[0139] 17 Outflow part

[0140] 18 Bottom

[0141] 20 outer cylinder

[0142] 21 Second Flow Path

[0143] 22 Bottom

[0144] 23 First inclined plane

[0145] 24 second slope

[0146] 25 Top

[0147] 26 Inflow section

[0148] 27 Outflow part

[0149] 28 Bottom

[0150] 30 Third tube

[0151] 31 Third Flow Path

[0152] 32 Inflow section

[0153] 33 Outflow part

[0154] 34 Bottom

[0155] 40 Flange portion

[0156] 41 Heat transfer element

[0157] 42 flow path body

[0158] 43. Three-dimensional shape section

[0159] 44 Flat sections

[0160] 45 Bottom

[0161] λ Maximum flow path width of the first flow path

[0162] μ gap (minimum flow path width of the first flow path)

[0163] d gap

Claims

1. A heat exchanger, a heat transfer body is arranged in a spiral shape in a space formed between a concentric inner cylinder and an outer cylinder, the space is divided into a first flow path and a second flow path by the heat transfer body, heat exchange is performed between a first fluid flowing in the first flow path and a second fluid flowing in the second flow path via the heat transfer body, characterized in that the inner cylinder, the outer cylinder and the heat transfer body are assembled in a manner that can be separated into a side where the outer cylinder is present and a side where the inner cylinder is present, in a state where the side where the outer cylinder is present and the side where the inner cylinder is present are separated, a flow path constituting surface that defines the first flow path is separated into the side where the outer cylinder is present and the side where the inner cylinder is present, and all surfaces of the flow path constituting surface that defines the first flow path are directly exposed without being obstructed by other portions when viewed in a radial direction that is orthogonal to an axial direction, the first flow path and the second flow path are each a flow path that is arranged in a spiral shape, a ratio (λ / μ) of a maximum flow path width (λ) of the first flow path in the radial direction to a minimum flow path width (μ) of the first flow path is 2 or more (2≤λ / μ<∞).

2. The heat exchanger according to claim 1, characterized in that the heat transfer body is fixed to either one of the side where the outer cylinder is present and the side where the inner cylinder is present, is not fixed to the other one of the side where the outer cylinder is present and the side where the inner cylinder is present, and has a three-dimensional shaped portion that has at least one bent portion and can form a space in which a fluid can flow on both an inner surface side and an outer surface side thereof, all of the bent portions present on the flow path constituting surface that defines the first flow path have an outer angle of 90 degrees or more.

3. The heat exchanger according to claim 1 or 2, characterized in that the first flow path and the second flow path do not have a horizontal portion in which the first fluid and the second fluid are likely to be accumulated.

4. The heat exchanger according to claim 1 or 2, characterized in that a gap of 4 mm or less is present in the radial direction between adjacent winding portions in the axial direction of the first flow path.

5. The heat exchanger according to claim 1 or 2, characterized in that the first flow path and the second flow path have a cross-sectional shape that is a substantially triangular shape having an apex angle (θ) of 30 degrees or more and 125 degrees or less in an axial cross-sectional view.

6. The heat exchanger according to claim 1 or 2, characterized in that the side where the inner cylinder is present and the side where the outer cylinder is present are assembled so as to be separable by movement in the axial direction without rotation, and the heat transfer body does not interfere with other portions when moved in the axial direction.

7. The heat exchanger according to claim 1 or 2, characterized in that the first flow path and the second flow path have a cross-sectional shape that is a substantially triangular shape having two inclined surfaces, a bottom surface and an apex portion, and an axial length (a) of the apex portion is shorter than an axial length (b) of the inclined surfaces.

8. The heat exchanger according to claim 7, characterized in that The top portion of at least either one of the first flow path and the second flow path has a length (a) in the axial direction, and the cross-sectional area of the flow path is larger than that of a case where the top portion has no length (a) in the axial direction.

9. The heat exchanger according to claim 1 or 2, wherein The space formed between the inner tube and the outer tube arranged concentrically has a plurality of portions concentrically.

10. The heat exchanger according to claim 1 or 2, wherein At least either one of a through flow path for the first fluid including the first flow path and a through flow path for the second fluid including the second flow path is implemented with a coating layer using a corrosion-resistant material.

11. The heat exchanger according to claim 10, wherein The coating layer using a corrosion-resistant material is one of a glass lining or a fluororesin coating layer, a ceramic coating layer.

12. The heat exchanger according to claim 3, wherein A gap in the radial direction is provided between adjacent ring portions in the axial direction of the first flow path.

13. The heat exchanger according to claim 3, wherein The first flow path and the second flow path have a cross-sectional shape in an axial cross-sectional view that is a substantially triangular shape with an apex angle (θ) of 30 degrees or more and 125 degrees or less.

14. The heat exchanger according to claim 4, wherein The first flow path and the second flow path have a cross-sectional shape in an axial cross-sectional view that is a substantially triangular shape with an apex angle (θ) of 30 degrees or more and 125 degrees or less.

15. The heat exchanger according to claim 3, wherein The first flow path and the second flow path have a cross-sectional shape in an axial cross-sectional view that is a substantially triangular shape having two inclined surfaces, a bottom surface, and a top portion, the axial length (a) of the top portion being shorter than the axial length (b) of the inclined surfaces.

16. The heat exchanger according to claim 4, wherein The first flow path and the second flow path have a cross-sectional shape in an axial cross-sectional view that is a substantially triangular shape having two inclined surfaces, a bottom surface, and a top portion, the axial length (a) of the top portion being shorter than the axial length (b) of the inclined surfaces.

17. The heat exchanger according to claim 5, wherein The first flow path and the second flow path have a cross-sectional shape in an axial cross-sectional view that is a substantially triangular shape having two inclined surfaces, a bottom surface, and a top portion, the axial length (a) of the top portion being shorter than the axial length (b) of the inclined surfaces.

18. The heat exchanger according to claim 6, wherein The first flow path and the second flow path have a cross-sectional shape in an axial cross-sectional view that is a substantially triangular shape having two inclined surfaces, a bottom surface, and a top portion, the axial length (a) of the top portion being shorter than the axial length (b) of the inclined surfaces.

19. The heat exchanger according to claim 3, wherein The space formed between the inner tube and the outer tube arranged concentrically has a plurality of portions concentrically.

20. The heat exchanger according to claim 4, wherein The space formed between the inner tube and the outer tube arranged concentrically has a plurality of portions concentrically.

21. The heat exchanger according to claim 5, wherein the space formed between the inner tube and the outer tube arranged concentrically has a plurality of the spaces concentrically.

22. The heat exchanger according to claim 6, wherein the space formed between the inner tube and the outer tube arranged concentrically has a plurality of the spaces concentrically.

23. The heat exchanger according to claim 7, wherein the space formed between the inner tube and the outer tube arranged concentrically has a plurality of the spaces concentrically.

24. The heat exchanger according to claim 8, wherein the space formed between the inner tube and the outer tube arranged concentrically has a plurality of the spaces concentrically.

25. The heat exchanger according to claim 3, wherein at least either one of a through flow path for the first fluid including the first flow path and a through flow path for the second fluid including the second flow path is implemented with a coating layer using a corrosion-resistant material.

26. The heat exchanger according to claim 4, wherein at least either one of a through flow path for the first fluid including the first flow path and a through flow path for the second fluid including the second flow path is implemented with a coating layer using a corrosion-resistant material.

27. The heat exchanger according to claim 5, wherein at least either one of a through flow path for the first fluid including the first flow path and a through flow path for the second fluid including the second flow path is implemented with a coating layer using a corrosion-resistant material.

28. The heat exchanger according to claim 6, wherein at least either one of a through flow path for the first fluid including the first flow path and a through flow path for the second fluid including the second flow path is implemented with a coating layer using a corrosion-resistant material.

29. The heat exchanger according to claim 7, wherein at least either one of a through flow path for the first fluid including the first flow path and a through flow path for the second fluid including the second flow path is implemented with a coating layer using a corrosion-resistant material.

30. The heat exchanger according to claim 8, wherein at least either one of a through flow path for the first fluid including the first flow path and a through flow path for the second fluid including the second flow path is implemented with a coating layer using a corrosion-resistant material.

31. The heat exchanger according to claim 9, wherein at least either one of a through flow path for the first fluid including the first flow path and a through flow path for the second fluid including the second flow path is implemented with a coating layer using a corrosion-resistant material. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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