Heat exchanger

Abstract

To provide a heat exchanger that can restrain mixing of a first fluid and a second fluid.SOLUTION: A heat exchanger comprises a first honeycomb structure 10, a first cylindrical member 20, and a second honeycomb structure 30. The first honeycomb structure 10 comprises: an outer peripheral wall 11; and a partition wall 13 arranged inside the outer peripheral wall 11, and partitioning and forming a plurality of cells 12 serving as flow passages for a first fluid. The first cylindrical member 20 is fitted to the outer peripheral wall 11 of the first honeycomb structure 10. The second honeycomb structure 30 comprises: an outer peripheral wall 31; an inner peripheral wall 35; and a partition wall 33 arranged between the outer peripheral wall 31 and the inner peripheral wall 35, and partitioning and forming a plurality of cells 32 serving as flow passages for a second fluid. The inner peripheral wall 35 is fitted to the first cylindrical member 20.SELECTED DRAWING: Figure 1A

Description

[Technical Field]

[0001] The present invention relates to a heat exchanger. [Background technology]

[0002] Heat exchangers that use heat sources such as exhaust gas to preheat fuel air or steam have been introduced into various systems. For example, there are heat exchangers that preheat combustion air using exhaust gas from boilers used in thermal power plants as a heat source, and heat exchangers that generate and preheat steam using exhaust gas from fuel cells as a heat source. Systems that incorporate such heat exchangers are known to be effective in reducing energy consumption because they reuse waste heat energy from exhaust gas and other sources.

[0003] Patent Document 1 proposes a heat exchanger for use in the above technology, which includes a heat collection section formed as a honeycomb structure having a plurality of cells that penetrate from one end to the other and serve as a flow path for a first fluid, and partition walls that are primarily made of ceramic and that separate the plurality of cells; a heat transfer section that has an outer peripheral wall that is primarily made of ceramic and is provided on the periphery of the heat collection section, and that mediates the transfer of heat between the first fluid and the second fluid while separating the first fluid from a second fluid flowing on the outer periphery of the heat collection section by the outer peripheral wall; and an intermediate wall that is primarily made of ceramic and is thicker than the partition wall, and that surrounds a central cell of the plurality of cells to separate the central cell from the remaining peripheral cells.

[0004] Furthermore, as a heat exchanger particularly suitable for heat exchange between gases, Patent Document 2 proposes a heat exchanger having a ceramic structure whose main component is ceramic, which has a three-dimensional mesh structure having partition walls and / or communicating pores that define cells in 2 x 2 or more rows that form a first fluid circulation section, which is a first flow path, and partition walls and / or the three-dimensional mesh structure that define multiple cells that form a second fluid circulation section, which is a flow path for a second fluid, on its periphery via intermediate walls, and an outer periphery of the three-dimensional mesh structure, and at least one pair of inlet sections through which the second fluid flows into the second fluid circulation section from the outside and outlet sections that discharge the second fluid that has flowed into the second fluid circulation section to the outside are provided on a part of the outer periphery wall. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-189229 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-042934 Summary of the Invention [Problem to be solved by the invention]

[0006] In both of the heat exchangers of Patent Documents 1 and 2, a flow path for a first fluid and a flow path for a second fluid are separated by an intermediate wall. However, because the intermediate wall is made of a material whose main component is ceramic, there is a concern that each fluid may flow into a different flow path through the pores in the intermediate wall, resulting in the fluids becoming mixed together.

[0007] The present invention has been made to solve the above-mentioned problems, and has an object to provide a heat exchanger that can suppress mixing of a first fluid and a second fluid. [Means for solving the problem]

[0008] The present inventors have found that the above-mentioned problems can be solved by disposing a tubular member between two types of honeycomb structures, and have thus completed the present invention. That is, the present invention is exemplified as follows.

[0009] [1] A first honeycomb structure having an outer peripheral wall and partition walls disposed inside the outer peripheral wall and defining a plurality of cells that serve as flow paths for a first fluid; a first cylindrical member fitted to the outer peripheral wall of the first honeycomb structure; a second honeycomb structure having an outer peripheral wall, an inner peripheral wall, and partition walls disposed between the outer peripheral wall and the inner peripheral wall to define a plurality of cells serving as flow paths for a second fluid, the inner peripheral wall of the second honeycomb structure being fitted into the first cylindrical member; A heat exchanger comprising:

[0010] [2] The heat exchanger described in [1], further comprising a thermal conductive material arranged between the first honeycomb structure and the first tubular member and / or between the second honeycomb structure and the first tubular member.

[0011] [3] A heat exchanger according to [1] or [2], wherein, in the axial direction of the first honeycomb structure and the second honeycomb structure, both end faces of the second honeycomb structure are located more inward than both end faces of the first honeycomb structure.

[0012] [4] A heat exchanger described in any one of [1] to [3], wherein, in the axial direction of the first honeycomb structure and the second honeycomb structure, both end portions of the first tubular member are positioned outside both end faces of the first honeycomb structure and the second honeycomb structure.

[0013] [5] A heat exchanger according to any one of [1] to [4], wherein in a cross section perpendicular to the direction in which the cells of the first honeycomb structure and the second honeycomb structure extend, the partition walls have first partition walls extending in the circumferential direction and second partition walls extending in the radial direction.

[0014] [6] The heat exchanger according to any one of [1] to [5], wherein the second honeycomb structure is divided into a plurality of sections in a cross section perpendicular to the direction in which the cells of the second honeycomb structure extend.

[0015] [7] The heat exchanger according to any one of [1] to [6], wherein the first honeycomb structure and / or the second honeycomb structure is mainly composed of ceramics.

[0016] [8] The heat exchanger according to [7], wherein the ceramic is mainly composed of silicon carbide.

[0017] [9] The heat exchanger according to any one of [1] to [8], wherein the first cylindrical member is made of a metal material.

[0018]

[10] The heat exchanger according to any one of [1] to [9], wherein at least one end of the first cylindrical member is reduced in diameter or expanded in diameter.

[0019]

[11] A heat exchanger described in any one of [1] to

[10] , further comprising a second tubular member fitted to at least a portion of the outer wall of the second honeycomb structure, the second tubular member having an inlet and an outlet for the second fluid.

[0020]

[12] The heat exchanger according to

[11] , further comprising a heat insulating material disposed between the second honeycomb structure and the second tubular member.

[0021]

[13] The heat exchanger according to any one of [1] to

[12] , wherein the flow direction of the first fluid and the flow direction of the second fluid are opposite to each other.

[0022]

[14] The heat exchanger according to any one of [1] to

[13] , wherein the first honeycomb structure further has an inner peripheral wall that defines a hollow region inside the first honeycomb structure, the hollow region serving as a flow path for a third fluid.

[0023]

[15] A heat exchanger as described in

[14] , further comprising a third tubular member fitted to at least a portion of the inner peripheral wall of the first honeycomb structure, the third tubular member having an inlet and an outlet for the third fluid. [Effects of the Invention]

[0024] According to the present invention, it is possible to provide a heat exchanger that can suppress mixing of a first fluid and a second fluid. [Brief explanation of the drawings]

[0025] [Figure 1A] 1 is a cross-sectional view parallel to the extending direction of cells of a heat exchanger according to a first embodiment of the present invention. [Figure 1B] 1B is a cross-sectional view of the heat exchanger of FIG. 1A taken along line aa'. [Figure 2A] 4 is a cross-sectional view perpendicular to the direction in which the cells of another heat exchanger according to the first embodiment of the present invention extend. FIG. [Figure 2B] 4 is a cross-sectional view perpendicular to the direction in which the cells of another heat exchanger according to the first embodiment of the present invention extend. FIG. [Figure 3A] 4 is a cross-sectional view parallel to the extending direction of the cells of another heat exchanger according to the first embodiment of the present invention. FIG. [Figure 3B] 4 is a cross-sectional view parallel to the extending direction of the cells of another heat exchanger according to the first embodiment of the present invention. FIG. [Figure 4A] FIG. 4 is a cross-sectional view parallel to the extending direction of the cells of a heat exchanger according to a second embodiment of the present invention. [Figure 4B] FIG. 4B is a cross-sectional view of the heat exchanger of FIG. 4A taken along line bb'. [Figure 5] FIG. 6 is a cross-sectional view parallel to the extending direction of the cells of a heat exchanger according to a third embodiment of the present invention. [Figure 6] FIG. 10 is a cross-sectional view parallel to the extending direction of the cells of another heat exchanger according to the third embodiment of the present invention. [Figure 7A] FIG. 10 is a cross-sectional view parallel to the extending direction of the cells of a heat exchanger according to a fourth embodiment of the present invention. [Figure 7B] FIG. 7B is a cross-sectional view of the heat exchanger of FIG. 7A taken along line cc'. [Figure 8A] FIG. 10 is a cross-sectional view parallel to the extending direction of the cells of another heat exchanger according to the fourth embodiment of the present invention. [Figure 8B] FIG. 8B is a cross-sectional view of the heat exchanger of FIG. 8A taken along line dd'. DETAILED DESCRIPTION OF THE INVENTION

[0026] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following embodiments, and it should be understood that modifications and improvements made to the following embodiments based on the ordinary knowledge of those skilled in the art without departing from the spirit of the present invention are also within the scope of the present invention.

[0027] <Embodiment 1> Fig. 1A is a cross-sectional view parallel to the extension direction of the cells of the heat exchanger according to the first embodiment of the present invention, and Fig. 1B is a cross-sectional view of the heat exchanger of Fig. 1A taken along line a-a' (a cross-sectional view perpendicular to the extension direction of the cells of the heat exchanger of Fig. 1A). 1A and 1B, the heat exchanger according to the first embodiment of the present invention includes a first honeycomb structure 10, a first tubular member 20, and a second honeycomb structure 30. The first honeycomb structure 10 has an outer peripheral wall 11 and partition walls 13 disposed inside the outer peripheral wall 11 to define a plurality of cells 12 serving as flow paths for a first fluid. The first tubular member 20 is fitted to the outer peripheral wall 11 of the first honeycomb structure 10. The second honeycomb structure 30 has an outer peripheral wall 31, an inner peripheral wall 35, and partition walls 33 disposed between the outer peripheral wall 31 and the inner peripheral wall 35 to define a plurality of cells 32 serving as flow paths for a second fluid. The inner peripheral wall 35 of the second honeycomb structure 30 is fitted to the first tubular member 20. A heat exchanger having such a structure has a first tubular member 20 arranged between a first honeycomb structure 10 through which a first fluid flows and a second honeycomb structure 30 through which a second fluid flows, thereby suppressing mixing of the first fluid and the second fluid. In this specification, the term "heat exchanger" refers to a device or component used to exchange thermal energy between two different fluids (e.g., a first fluid and a second fluid). When the term "heat exchanger" refers to a device, it may further include known components necessary to configure the device.

[0028] (First honeycomb structure 10) The first honeycomb structure 10 has an outer peripheral wall 11 and partition walls 13 disposed inside the outer peripheral wall 11 and defining a plurality of cells 12 that serve as flow paths for a first fluid. The flow paths for the first fluid extend from one end face 14a to the other end face 14b. The shape of the first honeycomb structure 10 is not particularly limited, and in a cross section perpendicular to the extension direction of the cells 12, it can be circular as shown in FIG. 1B, as well as elliptical, rectangular, or other polygonal shapes. The shape of the cells 12 is not particularly limited, and in a cross section perpendicular to the direction in which the cells 12 extend, they may be rectangular as shown in FIG. 1B, or may be circular, elliptical, triangular, hexagonal, or other polygonal.

[0029] 1B, the partition walls 13 preferably have first partition walls 13a extending in the circumferential direction and second partition walls 13b extending in the radial direction in a cross section perpendicular to the extension direction of the cells 12 of the first honeycomb structure 10. With this configuration, heat exchange between the first fluid flowing through the cells 12 of the first honeycomb structure 10 and the second fluid flowing through the cells 32 of the second honeycomb structure 30 can be efficiently performed.

[0030] The thickness of the partition walls 13 is not particularly limited, but is preferably 0.05 to 1.0 mm, and more preferably 0.2 to 0.6 mm. By making the thickness of the partition walls 13 0.05 mm or more, it is possible to ensure sufficient mechanical strength of the first honeycomb structure 10. Furthermore, by making the thickness of the partition walls 13 1.0 mm or less, it is possible to suppress problems such as an increase in pressure loss due to a decrease in opening area and a decrease in heat recovery efficiency due to a decrease in contact area with the first fluid.

[0031] Although there are no particular limitations on the thickness of outer peripheral wall 11, it is preferable that the thickness be greater than the thickness of partition wall 13. This configuration can increase the strength of outer peripheral wall 11, which is prone to damage (for example, cracks, fractures, etc.) due to external impacts, thermal stress caused by the temperature difference between the first fluid and the second fluid, and the like. The thickness of the outer peripheral wall 11 is not particularly limited and may be adjusted appropriately depending on the application, etc. For example, the thickness of the outer peripheral wall 11 is preferably 0.1 mm to 10 mm, more preferably 0.5 mm to 5 mm, and even more preferably 1 mm to 3 mm.

[0032] The first honeycomb structure 10 (the outer peripheral wall 11 and the partition walls 13) is mainly composed of ceramics. "Mainly composed of ceramics" means that the mass ratio of ceramics to the mass of all components is 50 mass % or more. By using ceramics, it is possible to suppress rust and deformation while achieving weight reduction.

[0033] The ceramic is not particularly limited, but is preferably composed primarily of silicon carbide (SiC). Examples of ceramics containing silicon carbide (SiC) as the main component include Si-impregnated SiC, (Si+Al)-impregnated SiC, metal composite SiC, recrystallized SiC, Si3N4, and SiC. Among these, it is preferable to use Si-impregnated SiC and (Si+Al)-impregnated SiC because they can be produced inexpensively and have high thermal conductivity.

[0034] The porosity of the outer peripheral wall 11 and the partition walls 13 is not particularly limited, but is preferably 10% or less, more preferably 5% or less, and even more preferably 3% or less. By setting the porosity of the outer peripheral wall 11 and the partition walls 13 to 10% or less, the thermal conductivity can be improved. Here, the term "porosity" in this specification refers to the porosity measured by mercury intrusion porosimetry in accordance with JIS R1655:2003.

[0035] The cell density (i.e., the number of cells 12 per unit area) of the first honeycomb structure 10 in a cross section perpendicular to the extending direction of the cells 12 is not particularly limited, but is preferably 4 to 320 cells / cm. 2 The cell density is 4 cells / cm 2 By setting the cell density to the above, it is possible to sufficiently secure the strength of the partition walls 13, and in turn the strength and effective GSA (geometric surface area) of the first honeycomb structure 10 itself. 2 By setting the above, it is possible to suppress an increase in pressure loss when the first fluid flows.

[0036] The isostatic strength of the first honeycomb structure 10 is not particularly limited, but is preferably 100 MPa or more, more preferably 150 MPa or more, and even more preferably 200 MPa or more. By making the isostatic strength of the first honeycomb structure 10 100 MPa or more, the durability of the first honeycomb structure 10 can be improved. Here, the "isostatic strength" in this specification can be measured in accordance with the method for measuring isostatic strength specified in JASO standard M505-87, an automotive standard issued by the Society of Automotive Engineers of Japan.

[0037] The diameter (outer diameter) of the outer wall 11 of the first honeycomb structure 10 in a cross section perpendicular to the extension direction of the cells 12 is not particularly limited, but is preferably 20 to 200 mm, more preferably 30 to 150 mm. By setting the diameter in this range, it is possible to improve the heat recovery efficiency. When the outer wall 11 is not circular, the diameter of the outer wall 11 is defined as the diameter of the largest inscribed circle inscribed in the cross-sectional shape of the outer wall 11.

[0038] The thermal conductivity of the first honeycomb structure 10 is not particularly limited, but is preferably 50 W / (m·K) or more, more preferably 100 to 300 W / (m·K), and even more preferably 120 to 300 W / (m·K) at 25° C. By setting the thermal conductivity of the first honeycomb structure 10 within this range, the thermal conductivity is improved, and therefore heat exchange between the first fluid flowing through the cells 12 of the first honeycomb structure 10 and the second fluid flowing through the cells 32 of the second honeycomb structure 30 can be efficiently performed. Here, the term "thermal conductivity" in this specification refers to a value measured by the laser flash method (JIS R1611:2010).

[0039] (Second honeycomb structure 30) The second honeycomb structure 30 has an outer peripheral wall 31, an inner peripheral wall 35, and partition walls 33 disposed between the outer peripheral wall 31 and the inner peripheral wall 35 to define a plurality of cells 32 that serve as flow paths for the second fluid. The flow paths for the second fluid extend from one end face 34a to the other end face 34b.

[0040] Both end faces 34a, 34b of the second honeycomb structure 30 are preferably located more inward than both end faces 14a, 14b of the first honeycomb structure 10 in the axial direction (the direction in which the cells 12, 32 extend) of the first honeycomb structure 10 and the second honeycomb structure 30. With this configuration, it becomes easier to provide an inlet (for example, the end face 34b) and an outlet (for example, the end face 34a) for the second fluid flowing through the second honeycomb structure 30, avoiding the flow of the first fluid.

[0041] The second honeycomb structure 30 may be divided into a plurality of parts in a cross section perpendicular to the extension direction of the cells 32. Dividing the second honeycomb structure 30 into a plurality of parts makes it easier to manufacture the heat exchanger. 2A and 2B show cross-sectional views perpendicular to the cell extension direction of a heat exchanger including a second honeycomb structure 30 divided into multiple pieces. Fig. 2A shows an example of a heat exchanger including a second honeycomb structure 30 divided into four pieces, and Fig. 2B shows an example of a heat exchanger including a second honeycomb structure 30 divided into two pieces. The number of divisions of the second honeycomb structure 30 is not particularly limited, but is typically 2 to 10. The sizes of the individual divided second honeycomb structures 30 may be the same or different.

[0042] The outer shape of the second honeycomb structure 30 (the shape of the outer wall 31) is not particularly limited, and in a cross section perpendicular to the extension direction of the cells 32, it can be circular as shown in Figure 1B, as well as elliptical, rectangular, or other polygonal shapes. The inner shape (shape of the inner peripheral wall 35) of the second honeycomb structure 30 is not particularly limited, and in a cross section perpendicular to the extension direction of the cells 32, it can be circular as shown in Figure 1B, as well as elliptical, rectangular, or other polygonal shapes. The outer and inner shapes of the second honeycomb structure 30 may be the same or different, but are preferably the same from the viewpoint of resistance to external impacts, thermal stress, etc. When the second honeycomb structure 30 is divided into a plurality of pieces, the outer and inner shapes of the second honeycomb structure 30 refer to the outer and inner shapes of the divided second honeycomb structures 30 when assembled. The shape of the cells 32 is not particularly limited, and in a cross section perpendicular to the direction in which the cells 32 extend, the shape may be a rectangle as shown in FIG. 1B, a circle, an ellipse, a triangle, a hexagon, or any other polygon.

[0043] 1B, in a cross section perpendicular to the extension direction of the cells 32 of the second honeycomb structure 30. It is preferable that the partition walls 33 have first partition walls 33a extending in the circumferential direction and second partition walls 33b extending in the radial direction. With this configuration, heat exchange between the first fluid flowing through the cells 12 of the first honeycomb structure 10 and the second fluid flowing through the cells 32 of the second honeycomb structure 30 can be efficiently performed.

[0044] The thickness of the partition walls 33 is not particularly limited, but is preferably 0.05 to 1.0 mm, and more preferably 0.2 to 0.6 mm. By making the thickness of the partition walls 33 0.05 mm or more, it is possible to ensure sufficient mechanical strength of the second honeycomb structure 30. Furthermore, by making the thickness of the partition walls 33 1.0 mm or less, it is possible to suppress problems such as an increase in pressure loss due to a decrease in the opening area and a decrease in heat recovery efficiency due to a decrease in the contact area with the second fluid.

[0045] Although there are no particular limitations on the thickness of the outer peripheral wall 31 and the inner peripheral wall 35, they are preferably larger than the thickness of the partition wall 33. This configuration can increase the strength of the outer peripheral wall 31 and the inner peripheral wall 35, which are prone to damage (for example, cracks, fractures, etc.) due to external impacts, thermal stress caused by the temperature difference between the first fluid and the second fluid, and the like. The thickness of the outer peripheral wall 31 and the inner peripheral wall 35 is not particularly limited and may be adjusted appropriately depending on the application, etc. For example, the thickness of the outer peripheral wall 31 and the inner peripheral wall 35 is preferably 0.1 mm to 10 mm, more preferably 0.5 mm to 5 mm, and even more preferably 1 mm to 3 mm.

[0046] The second honeycomb structure 30 (the outer peripheral wall 31, the inner peripheral wall 35, and the partition walls 33) is mainly composed of ceramics. "Mainly composed of ceramics" means that the mass ratio of ceramics to the mass of all components is 50 mass% or more. By using ceramics, it is possible to reduce the weight while suppressing rust and deformation.

[0047] The ceramic is not particularly limited, but is preferably composed primarily of silicon carbide (SiC). Examples of ceramics containing silicon carbide (SiC) as the main component include Si-impregnated SiC, (Si+Al)-impregnated SiC, metal composite SiC, recrystallized SiC, Si3N4, and SiC. Among these, it is preferable to use Si-impregnated SiC and (Si+Al)-impregnated SiC because they can be produced inexpensively and have high thermal conductivity.

[0048] The porosity of the outer peripheral wall 31, the inner peripheral wall 35, and the partition walls 33 is not particularly limited, but is preferably 10% or less, more preferably 5% or less, and even more preferably 3% or less. By setting the porosity of the outer peripheral wall 31, the inner peripheral wall 35, and the partition walls 33 to 10% or less, the thermal conductivity can be improved.

[0049] The cell density (i.e., the number of cells 32 per unit area) of the second honeycomb structure 30 in a cross section perpendicular to the extending direction of the cells 32 is not particularly limited, but is preferably 4 to 320 cells / cm. 2 The cell density is 4 cells / cm 2 By setting the cell density to the above, it is possible to sufficiently secure the strength of the partition walls 33, and in turn the strength and effective GSA (geometric surface area) of the second honeycomb structure 30 itself. 2 By setting the above, it is possible to suppress an increase in pressure loss when the second fluid flows.

[0050] The isostatic strength of the second honeycomb structure 30 is not particularly limited, but is preferably 100 MPa or more, more preferably 150 MPa or more, and even more preferably 200 MPa or more. By making the isostatic strength of the second honeycomb structure 30 100 MPa or more, the durability of the second honeycomb structure 30 can be improved.

[0051] The diameter (outer diameter) of the outer wall 31 of the second honeycomb structure 30 in a cross section perpendicular to the extension direction of the cells 32 is not particularly limited, but is preferably 30 to 400 mm, more preferably 40 to 300 mm. By setting the diameter in this range, it is possible to improve the heat recovery efficiency. When the outer wall 31 is not circular, the diameter of the outer wall 31 is defined as the diameter of the largest inscribed circle inscribed in the cross-sectional shape of the outer wall 31. Furthermore, the diameter (inner diameter) of the inner peripheral wall 35 of the second honeycomb structure 30 in a cross section perpendicular to the extension direction of the cells 32 is not particularly limited, but is preferably 20 to 200 mm, more preferably 30 to 150 mm. When the cross-sectional shape of the inner peripheral wall 35 is not circular, the diameter of the inner peripheral wall 35 is defined as the diameter of the largest inscribed circle inscribed in the cross-sectional shape of the inner peripheral wall 35. In addition, when the second honeycomb structure 30 is divided into multiple pieces, the diameters of the outer wall 31 and the inner wall 35 mean the diameters of the outer wall 31 and the inner wall 35 when the divided second honeycomb structures 30 are assembled together.

[0052] The thermal conductivity of the second honeycomb structure 30 is not particularly limited, but is preferably 50 W / (m·K) or more, more preferably 100 to 300 W / (m·K), and even more preferably 120 to 300 W / (m·K) at 25° C. By setting the thermal conductivity of the second honeycomb structure 30 within this range, the thermal conductivity is improved, and therefore heat exchange between the first fluid flowing through the cells 12 of the first honeycomb structure 10 and the second fluid flowing through the cells 32 of the second honeycomb structure 30 can be efficiently performed.

[0053] (First cylindrical member 20) The first cylindrical member 20 is disposed between the outer peripheral wall 11 of the first honeycomb structure 10 and the inner peripheral wall 35 of the second honeycomb structure 30 . The first cylindrical member 20 is a cylindrical member having two ends 21a and 21b, and allows the first fluid to flow inside.

[0054] Both end portions 21a, 21b of the first cylindrical member 20 are preferably located outside both end faces 14a, 14b of the first honeycomb structure 10 and both end faces 34a, 34b of the second honeycomb structure 30 in the axial direction (the direction in which the cells 12, 32 extend) of the first honeycomb structure 10 and the second honeycomb structure 30. With this configuration, it becomes easy to provide an inlet (for example, the end portion 21a) and an outlet (for example, the end portion 21b) for the first fluid flowing inside the first cylindrical member 20, avoiding the flow of the second fluid.

[0055] From the viewpoints of thermal conductivity and manufacturability, the first cylindrical member 20 is preferably made of a metal material. Examples of metals that can be used include stainless steel, titanium alloys, copper alloys, aluminum alloys, brass, nickel alloys, steel, lead, and lead alloys. Among these, stainless steel is preferred because of its low cost and high durability and reliability. Furthermore, to improve the corrosion resistance of the first cylindrical member 20, the first cylindrical member 20 may be subjected to a surface treatment such as a fluororesin lining or FRP lining.

[0056] From the viewpoint of stably suppressing mixing of the first fluid and the second fluid, the thickness of the first cylindrical member 20 is preferably 0.1 mm or more, more preferably 0.5 mm or more, and even more preferably 1 mm or more. From the viewpoints of cost, volume, weight, etc., the thickness of the first cylindrical member 20 is preferably 50 mm or less, more preferably 40 mm or less, and even more preferably 30 mm or less.

[0057] At least one of the ends 21a, 21b of the first cylindrical member 20 may be reduced or increased in diameter. Fig. 3A shows an example in which both ends 21a, 21b of the first cylindrical member 20 are increased in diameter, and Fig. 3B shows an example in which both ends 21a, 21b of the first cylindrical member 20 are reduced in diameter. Figs. 3A and 3B are cross-sectional views parallel to the extension direction of the cells 12, 32. By reducing or increasing the diameter of both ends 21a, 21b of the first cylindrical member 20, advantageous effects can be obtained in terms of manufacturing, such as making it easier to connect to other members. Although FIGS. 3A and 3B show examples in which both end portions 21a, 21b have a reduced diameter or an increased diameter, one of end portions 21a, 21b may have a reduced diameter or an increased diameter.

[0058] (First fluid and second fluid) The first fluid and the second fluid are not particularly limited and may be gas, liquid, etc. Typically, the first fluid and the second fluid are gas. For example, the first fluid is an exhaust gas emitted in the industrial field, and the second fluid is various gases that require heating. It is preferable that the flow direction of the first fluid and the flow direction of the second fluid are opposite to each other, which can improve the efficiency of heat exchange between the first fluid and the second fluid.

[0059] (Heat exchanger manufacturing method) The method for producing the heat exchanger is not particularly limited, and the heat exchanger can be produced according to a method known in the art. For example, the heat exchanger can be produced according to the method described below. First, each honeycomb structure (the first honeycomb structure 10 and the second honeycomb structure 30) is fabricated. Each honeycomb structure is fabricated as follows. First, a clay containing ceramic powder is extruded into a desired shape to fabricate a honeycomb formed body. At this time, by selecting an appropriate type of die and jig, the shape and density of the cells 12, 32, the shape and thickness of the outer peripheral walls 11, 31, the partition walls 13, 33, and the inner peripheral wall 35, etc. can be controlled. In addition, the above-mentioned ceramics can be used as the material for the honeycomb formed body. For example, when manufacturing a honeycomb formed body mainly composed of a Si-impregnated SiC composite material, a predetermined amount of SiC powder is added with a binder and water and / or an organic solvent, and the resulting mixture is kneaded to form a clay, which is then molded to obtain a honeycomb formed body of a desired shape. The resulting honeycomb formed body is then dried, and metal Si is impregnated into the honeycomb formed body and fired in a reduced pressure inert gas or vacuum, thereby obtaining each honeycomb structure.

[0060] Next, the first honeycomb structure 10 is inserted into the first cylindrical member 20, and the first cylindrical member 20 is fitted into the outer peripheral wall 11 of the first honeycomb structure 10 to obtain a bonded body of the first honeycomb structure 10 and the first cylindrical member 20. Next, this bonded body is inserted into the inside of the inner peripheral wall 35 of the second honeycomb structure 30, and the first cylindrical member 20 of the bonded body is fitted into the inner peripheral wall 35 of the second honeycomb structure 30. The arrangement and fitting order of the components are not limited to those described above, and may be changed as appropriate within the scope of manufacturability.

[0061] <Embodiment 2> Fig. 4A is a cross-sectional view parallel to the extension direction of the cells of the heat exchanger according to embodiment 2 of the present invention, and Fig. 4B is a cross-sectional view taken along line bb' of the heat exchanger of Fig. 4A (a cross-sectional view perpendicular to the extension direction of the cells of the heat exchanger of Fig. 4A). 4A and 4B, components denoted by the same reference numerals as those in the above figures indicate the same components, and detailed description thereof will be omitted.

[0062] The heat exchanger according to the second embodiment of the present invention further includes a heat conductive material 40 disposed between the first honeycomb structure 10 and the first cylindrical member 20 and / or between the second honeycomb structure 30 and the first cylindrical member 20. With this configuration, the heat exchange efficiency between the first fluid flowing through the cells 12 of the first honeycomb structure 10 and the second fluid flowing through the cells 32 of the second honeycomb structure 30 can be improved. 4A and 4B show an example in which the heat conductive material 40 is arranged both between the first honeycomb structure 10 and the first tubular member 20 and between the second honeycomb structure 30 and the first tubular member 20, but the heat conductive material 40 may also be arranged between the first honeycomb structure 10 and the first tubular member 20 or between the second honeycomb structure 30 and the first tubular member 20.

[0063] The thermally conductive material 40 is not particularly limited as long as it is a material having thermal conductivity, and examples thereof include a graphite sheet and a thermally conductive resin sheet.

[0064] The heat exchanger according to the second embodiment of the present invention can be manufactured in accordance with a method known in the art. Specifically, when arranging and fitting each member, a heat conductive material 40 may be disposed between the first honeycomb structure 10 and the first cylindrical member 20 and / or between the second honeycomb structure 30 and the first cylindrical member 20.

[0065] <Embodiment 3> FIG. 5 is a cross-sectional view parallel to the extending direction of the cells of the heat exchanger according to the third embodiment of the present invention. In FIG. 5, components denoted by the same reference numerals as those in the above figures indicate the same components, and detailed description thereof will be omitted.

[0066] The heat exchanger according to the third embodiment of the present invention further includes a second cylindrical member 50 fitted to at least a part of the outer peripheral wall 31 of the second honeycomb structure 30. The second cylindrical member 50 also has an inlet 51 and an outlet 52 for the second fluid. With this configuration, it becomes easy to provide the inlet 51 and the outlet 52 for the second fluid away from the flow of the first fluid.

[0067] From the viewpoint of manufacturability, the second cylindrical member 50 is preferably made of a metal material. Examples of metals that can be used include stainless steel, titanium alloys, copper alloys, aluminum alloys, brass, nickel alloys, steel, lead, and lead alloys. Among these, stainless steel is preferred because of its low cost and high durability and reliability. Furthermore, to improve the corrosion resistance of the second cylindrical member 50, the second cylindrical member 50 may be subjected to a surface treatment such as a fluororesin lining or FRP lining.

[0068] From the viewpoint of durability, the thickness of the second cylindrical member 50 is preferably 0.1 mm or more, more preferably 0.5 mm or more, and even more preferably 1 mm or more. From the viewpoints of cost, volume, weight, etc., the thickness of the second cylindrical member 50 is preferably 50 mm or less, more preferably 40 mm or less, and even more preferably 30 mm or less.

[0069] 6, a heat insulating material 60 may be further disposed between the second honeycomb structure 30 and the second tubular member 50. By providing the heat insulating material 60, heat radiation from the second tubular member 50 to the external space can be suppressed, and therefore the heat exchange efficiency between the first fluid flowing through the cells 12 of the first honeycomb structure 10 and the second fluid flowing through the cells 32 of the second honeycomb structure 30 can be improved. FIG. 6 is a cross-sectional view taken along a line parallel to the direction in which the cells of the heat exchanger extend.

[0070] The heat insulating material 60 is not particularly limited as long as it is a material having heat insulating properties, and examples thereof include glass wool, rock wool, and cellulose fiber.

[0071] The heat exchanger according to the third embodiment of the present invention can be manufactured in accordance with a method known in the art. Specifically, the second cylindrical member 50 is fitted to the outer wall 31 of the second honeycomb structure 30. The arrangement of the members and the fitting order are not limited to those described above and may be changed as appropriate within the range of feasibility of manufacturing. The fitting method may be the same as that described above.

[0072] <Embodiment 4> Fig. 7A is a cross-sectional view parallel to the extension direction of the cells of a heat exchanger according to embodiment 4 of the present invention, and Fig. 7B is a cross-sectional view of the heat exchanger of Fig. 7A taken along line c-c' (a cross-sectional view perpendicular to the extension direction of the cells of the heat exchanger of Fig. 7A). 7A and 7B, components denoted by the same reference numerals as those in the above figures indicate the same components, and detailed description thereof will be omitted.

[0073] In the heat exchanger according to the fourth embodiment of the present invention, the first honeycomb structure 10 further includes an inner peripheral wall 15 that defines a hollow region inside the first honeycomb structure 10, which serves as a flow path for the third fluid. With this configuration, heat exchange between the first fluid and the third fluid can be performed through the inner peripheral wall 15.

[0074] The thickness of the inner circumferential wall 15 is not particularly limited, but is preferably larger than the thickness of the partition wall 13. This configuration can increase the strength of the inner circumferential wall 15, which is prone to damage (for example, cracks, fractures, etc.) due to thermal stress caused by the temperature difference between the first fluid and the third fluid. The thickness of the inner peripheral wall 15 is not particularly limited and may be adjusted appropriately depending on the application, etc. For example, the thickness of the inner peripheral wall 15 is preferably 0.1 mm to 10 mm, more preferably 0.5 mm to 5 mm, and even more preferably 1 mm to 3 mm.

[0075] The shape of the inner peripheral wall 15 is not particularly limited, and may be a circle as shown in Fig. 7B, an ellipse, a rectangle, or another polygon, etc., in a cross section perpendicular to the extension direction of the cells 12. The shapes of the outer peripheral wall 11 and the inner peripheral wall 15 may be the same or different, but are preferably the same from the viewpoint of resistance to thermal stress, etc. Furthermore, the diameter (inner diameter) of the inner peripheral wall 15 in a cross section perpendicular to the extension direction of the cells 12 is not particularly limited, but is preferably 150 mm or less, more preferably 100 mm or less. When the cross-sectional shape of the inner peripheral wall 15 is not circular, the diameter of the inner peripheral wall 15 is defined as the diameter of the largest inscribed circle inscribed in the cross-sectional shape of the inner peripheral wall 15.

[0076] The third fluid is not particularly limited and may be a gas, a liquid, etc. A typical third fluid is a gas, for example, any gas that requires heating. It is preferable that the flow direction of the first fluid and the flow direction of the third fluid are opposite to each other, which can improve the efficiency of heat exchange between the first fluid and the third fluid.

[0077] The heat exchanger according to the fourth embodiment of the present invention may further include a third cylindrical member 70 fitted to at least a part of the inner peripheral wall 15 of the first honeycomb structure 10. Here, Figure 8A shows a cross-sectional view parallel to the extension direction of the cells of a heat exchanger equipped with a third cylindrical member 70, and Figure 8B shows a cross-sectional view of the heat exchanger of Figure 8A taken along line dd' (a cross-sectional view perpendicular to the extension direction of the cells of the heat exchanger of Figure 8A). 8A and 8B, the heat exchanger further includes a third cylindrical member 70 fitted to at least a part of the inner peripheral wall 15 of the first honeycomb structure 10. The third cylindrical member 70 has an inlet 71 and an outlet 72 for the third fluid. With this configuration, it is possible to stably suppress mixing of the first fluid and the third fluid.

[0078] The inlet (end) 71 and outlet (end) 72 of the third cylindrical member 70 are preferably located outside both end portions 21a, 21b of the first cylindrical member 20 in the axial direction of the first cylindrical member 20 and the third cylindrical member 70. With this configuration, the inlet 71 and outlet 72 for the third fluid can be easily provided away from the flow of the first fluid.

[0079] From the viewpoints of thermal conductivity and manufacturability, the third cylindrical member 70 is preferably made of a metal material. Examples of metals that can be used include stainless steel, titanium alloys, copper alloys, aluminum alloys, brass, nickel alloys, steel, lead, and lead alloys. Among these, stainless steel is preferred because of its low cost and high durability and reliability. Furthermore, to improve the corrosion resistance of the third cylindrical member 70, the third cylindrical member 70 may be subjected to a surface treatment such as a fluororesin lining or FRP lining.

[0080] From the viewpoint of stably suppressing mixing of the first fluid and the third fluid, the thickness of the third cylindrical member 70 is preferably 0.1 mm or more, more preferably 0.5 mm or more, and even more preferably 1 mm or more. From the viewpoints of cost, volume, weight, etc., the thickness of the third cylindrical member 70 is preferably 50 mm or less, more preferably 40 mm or less, and even more preferably 30 mm or less.

[0081] The third cylindrical member 70 may have at least one end (the inlet 71, the outlet 72) reduced or enlarged in diameter. By reducing or enlarging the diameter of the end of the third cylindrical member 70, advantageous effects can be obtained in terms of manufacturing, such as making it easier to connect to other members.

[0082] The heat exchanger according to the fourth embodiment of the present invention can be manufactured in accordance with a method known in the art. Specifically, it can be manufactured in the same manner as the heat exchanger according to the first embodiment of the present invention, except that a honeycomb formed body is manufactured by selecting a die and a jig of an appropriate shape so as to obtain a first honeycomb structure 10 having an inner peripheral wall 15. When the third cylindrical member 70 is provided, the third cylindrical member 70 can be fitted to the inner peripheral wall 15 of the first honeycomb structure 10. The arrangement and fitting order of the respective members are not limited to those described above and can be changed as appropriate within the range that allows manufacturing. The fitting method can be the same as that described above. [Explanation of symbols]

[0083] 10 First honeycomb structure 11 Peripheral wall 12 cells 13 Bulkhead 13a 1st bulkhead 13b 2nd bulkhead 14a, 14b end face 15 Inner wall 20 First cylindrical member 21a, 21b end 30 Second honeycomb structure 31 Outer wall 32 cells 33 Bulkhead 33a 1st bulkhead 33b 2nd bulkhead 34a,34b end face 35 Inner wall 40 Thermal Conductive Materials 50 second cylindrical member 51 Inlet 52 Outlet 60 Insulation 70 Third cylindrical member 71 Inlet 72 Outlet

Claims

1. a first honeycomb structure having an outer peripheral wall and partition walls disposed inside the outer peripheral wall to define a plurality of cells that serve as flow paths for a first fluid; a first cylindrical member fitted to the outer peripheral wall of the first honeycomb structure; a second honeycomb structure having an outer peripheral wall, an inner peripheral wall, and partition walls disposed between the outer peripheral wall and the inner peripheral wall to define a plurality of cells serving as flow paths for a second fluid, the inner peripheral wall of the second honeycomb structure being fitted into the first cylindrical member; A heat exchanger comprising:

2. The heat exchanger according to claim 1 , further comprising a thermally conductive material disposed between the first honeycomb structure and the first tubular member and / or between the second honeycomb structure and the first tubular member.

3. 3. The heat exchanger according to claim 1, wherein, in the axial direction of the first honeycomb structure and the second honeycomb structure, both end faces of the second honeycomb structure are located more inward than both end faces of the first honeycomb structure.

4. 3. A heat exchanger as described in claim 1 or 2, wherein, in the axial direction of the first honeycomb structure and the second honeycomb structure, both end portions of the first tubular member are located outside both end faces of the first honeycomb structure and the second honeycomb structure.

5. 3. A heat exchanger as described in claim 1 or 2, wherein in a cross section perpendicular to the direction in which the cells of the first honeycomb structure and the second honeycomb structure extend, the partition walls have first partition walls extending circumferentially and second partition walls extending radially.

6. 3. The heat exchanger according to claim 1, wherein the second honeycomb structure is divided into a plurality of sections in a cross section perpendicular to the direction in which the cells of the second honeycomb structure extend.

7. 3. The heat exchanger according to claim 1, wherein the first honeycomb structure and / or the second honeycomb structure is mainly composed of ceramics.

8. 8. The heat exchanger according to claim 7, wherein the ceramic is mainly composed of silicon carbide.

9. The heat exchanger according to claim 1 or 2, wherein the first cylindrical member is made of a metal material.

10. The heat exchanger according to claim 1 or 2, wherein at least one end of the first cylindrical member is reduced in diameter or expanded in diameter.

11. 3. The heat exchanger according to claim 1, further comprising a second cylindrical member fitted to at least a portion of the outer wall of the second honeycomb structure, the second cylindrical member having an inlet and an outlet for the second fluid.

12. The heat exchanger according to claim 11 , further comprising a heat insulating material disposed between the second honeycomb structure and the second tubular member.

13. The heat exchanger according to claim 1 or 2, wherein a flow direction of the first fluid and a flow direction of the second fluid are opposite to each other.

14. 3. The heat exchanger according to claim 1, wherein the first honeycomb structure further has an inner peripheral wall defining a hollow region therein that serves as a flow path for a third fluid.

15. The heat exchanger according to claim 14, further comprising a third cylindrical member fitted to at least a portion of the inner peripheral wall of the first honeycomb structure, the third cylindrical member having an inlet and an outlet for the third fluid.

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