JP6012809B2 - Thermal conduction member - Google Patents

Description

  The present invention relates to a heat conducting member in which a cylindrical ceramic body is covered with a metal tube.

  By exchanging heat from a high temperature fluid to a low temperature fluid, heat can be effectively utilized. For example, there is a heat recovery technique for recovering heat from a high-temperature gas such as combustion exhaust gas from an engine. As the gas / liquid heat exchanger, a tube-type heat exchanger with fins such as an automobile radiator or an air conditioner outdoor unit is generally used. However, in order to recover heat from a gas such as automobile exhaust gas, a general metal heat exchanger has poor heat resistance and is difficult to use at high temperatures. Therefore, a heat-resistant metal or ceramic material having heat resistance, thermal shock resistance, corrosion resistance, or the like is suitable. However, refractory metals have problems such as high price and difficulty in processing, high density and heavyness, and low heat conduction.

  Therefore, a heat recovery technique using a ceramic material has been developed. For example, there is a technique for performing heat exchange using a cylindrical ceramic body. In this case, heat exchange is performed by circulating the first fluid inside the cylindrical ceramic body and circulating the second fluid outside. When heat is exchanged between a gas and a liquid using a cylindrical ceramic body, it is necessary to shield the cylindrical ceramic body so that the cylindrical ceramic body does not leak and the two fluids do not mix.

  Thus, a technique for recovering heat by integrating a ceramic honeycomb structure, which is a cylindrical ceramic body, and a metal substrate (metal tube) is disclosed (for example, Patent Document 1).

JP-A-9-327627

  However, when the ceramic honeycomb structure and the metal substrate (metal tube) are integrated, the thermal expansion coefficient differs between the honeycomb structure and the metal substrate (metal tube). In some cases, the degree of expansion or contraction differs greatly between the material (metal tube) and the honeycomb structure, and in such a case, excessive stress is generated in the honeycomb structure.

  In particular, when joining by brazing, molten metal joining, or the like, the cylindrical ceramic body or the metal tube can be chemically bonded to the metal provided in these gaps. In the case of such a joining form, heat transfer characteristics can be made very good, but a large thermal (residual) stress is applied during cooling due to the difference in thermal expansion coefficient between ceramics and metal. Also, when at least a part of the product becomes hot, such as when used for heat recovery purposes, it becomes complicated because the stress state is compounded, and it is damaged by repeated heat cycles. Problems are likely to occur. In particular, measures are required for the longitudinal direction (axial direction).

  There is also a method of integrating the cylindrical ceramic body and the metal tube by shrink fitting, but for the cylindrical ceramic body and the cylindrical metal tube, the outer and inner diameter tolerances must be managed accurately. However, there is a disadvantage that the processing of ceramics is essential and the cost is high. In addition, in the case of shrink fitting, since there is no chemical bonding, the heat transfer characteristics are not as good as those of brazing or molten metal bonding.

  The object of the present invention is to reduce the thermal stress caused by the difference in the thermal expansion coefficient between ceramic and metal while maintaining a good thermal bonding state when the cylindrical ceramic body is covered with a metal tube. An object of the present invention is to provide a heat conduction member having high exchange efficiency and high durability.

  The present invention solves the above problems. Specifically, the present invention is the following heat conducting member.

[1] A cylindrical ceramic body having a flow path that passes from one end face to the other end face and through which a first fluid that is a heating body flows, and an outer peripheral wall is provided on the outer periphery thereof, and the cylindrical ceramics A metal tube having an annular pleat surrounding the outer peripheral surface of the cylindrical ceramic body and being fitted to the outer peripheral surface of the cylindrical ceramic body; and the cylindrical ceramic body being sandwiched between the cylindrical ceramic body and the metal tube A body and an intermediate material joined to the metal tube, wherein the metal tube has a pleated portion protruding outward, and a filler in a gap between the inner surface of the pleated portion of the metal tube and the intermediate material. The filler is expanded graphite, and the intermediate material is made of a metal formed by casting with a molten metal, or the filler is ceramic fiber of alumina or silica, and the intermediate material is wax Made of wood, front The first fluid is circulated inside the cylindrical ceramic body, the second fluid having a temperature lower than that of the first fluid is circulated on the outer peripheral surface side of the metal tube, and the first fluid and the second fluid are circulated. A heat conduction member that exchanges heat with a fluid.

[2] The heat conducting member according to [1], wherein the cylindrical ceramic body is a honeycomb structure including partition walls, and a plurality of cells serving as fluid flow paths are defined by the partition walls.

  The heat conducting member of the present invention is highly resistant to cracking and cracking in the cylindrical ceramic body.

It is a perspective view showing typically one embodiment of the heat conduction member of the present invention. It is a schematic diagram of the A-A 'cross section in FIG. It is a figure explaining an example of the method for manufacturing the heat conductive member shown by FIG. It is sectional drawing which shows typically other embodiment of the heat conductive member of this invention. It is a figure explaining an example of the method for manufacturing the heat conductive member shown by FIG. FIG. 6 is a schematic diagram of a B-B ′ cross section in FIG. 5. It is the schematic diagram which looked at another embodiment of the heat conductive member of this invention from the one end surface of the axial direction. It is a schematic diagram which shows the heat exchanger containing the heat conductive member of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the following embodiments, and changes, modifications, and improvements can be added without departing from the scope of the present invention.

  The heat conducting member of the present invention is fitted to a cylindrical ceramic body having a flow path through which a first fluid as a heating body flows from one end surface to the other end surface, and an outer peripheral surface of the cylindrical ceramic body. And a metal tube having an annular pleat surrounding the outer periphery of the cylindrical ceramic body, and an intermediate material joined to the cylindrical ceramic body and the metal tube while being sandwiched between the cylindrical ceramic body and the metal tube. The heat conducting member of the present invention causes the first fluid to flow inside the cylindrical ceramic body, and the second fluid having a temperature lower than that of the first fluid to circulate on the outer peripheral surface side of the metal tube. Heat exchange with the second fluid. In the heat conducting member of the present invention, the first fluid and the second fluid can be prevented from being mixed by joining and integrating the metal tube and the cylindrical ceramic body via an intermediate material. it can.

  In the heat conducting member of the present invention, since the metal tube has a pleat portion, it can expand and contract along the axial direction (the direction connecting one end surface and the other end surface). Therefore, in the heat conducting member of the present invention, the metal tube can freely move along the axial direction by the action of the pleats even when the expansion and contraction in the metal tube is different from the expansion and contraction in the cylindrical ceramic body or intermediate material. Therefore, it is difficult to apply a large stress from the metal tube to the cylindrical ceramic body. As a result, the heat conductive member of the present invention is less likely to crack or crack in the cylindrical ceramic body.

  Moreover, in the metal tube with which the heat conductive member of this invention is provided, the pleat part may be one piece or plural pieces. In addition, when there are a plurality of pleat portions, it is possible to adopt a mode in which the degree of expansion and contraction of the metal tube is different at each position along the axial direction, so that the metal tube can be further expanded and contracted. As a result, it is difficult to apply a large stress from the metal tube to the intermediate material or the cylindrical ceramic body. In the heat conductive member of the present invention, the metal tube may have a bellows structure in which the pleats are repeatedly formed along the axial direction. Thus, when the metal tube has a bellows structure, even when the expansion and contraction in the metal tube is different from the expansion and contraction in the cylindrical ceramic body or the intermediate material, the metal tube is greatly increased from the metal tube to the cylindrical ceramic body. Stress is further suppressed, and as a result, cracks and cracks are further less likely to occur in the cylindrical ceramic body.

  In the heat conducting member of the present invention, the metal tube may have a configuration in which the pleat portion protrudes outward. Alternatively, the metal tube may have a shape in which the fold portion is recessed inward. Next, these two pleat portions will be described with specific examples.

  First, a form in which the pleat portion protrudes outward will be described. FIG. 1 is a perspective view schematically showing one embodiment of a heat conducting member of the present invention. This heat conducting member 10 penetrates from one end surface 2 to the other end surface 2 and has a cylindrical ceramic body 11 having a flow path through which a first fluid as a heating body flows, and an outer peripheral surface of the cylindrical ceramic body 11 A metal tube 12 fitted to 7h, and an intermediate member 13 joined to the cylindrical ceramic body 11 and the metal tube 12 while being sandwiched between the cylindrical ceramic body 11 and the metal tube 12. Then, the first fluid and the second fluid are circulated inside the cylindrical ceramic body 11 and the second fluid having a temperature lower than that of the first fluid is circulated on the outer peripheral surface 12 h side of the metal tube 12. Heat exchange with the fluid can be performed.

  Further, in the heat conducting member 10, the metal tube 12 has an annular pleat 15 surrounding the outer periphery of the cylindrical ceramic body 11. The pleat portion 15 is formed by the metal tube 12 being bent toward the outer peripheral side and protruding. By this pleat 15, the metal tube 12 can be expanded and contracted along the axial direction (the direction connecting the one end surface 2 and the other end surface 2).

  2 is a schematic diagram of the A-A ′ cross section in FIG. 1 (the position of this cross section is indicated by a dotted line on the outer peripheral surface 12 h of the metal tube 12 in FIG. 1). As shown in the drawing, when the heat conducting member 10 is viewed from a cross-section of the cut along the axial direction (the direction in which the central axis 20 extends), the pleat 15 is formed on the one end face 2 with the top (peak) as a boundary. The side surface and the other end surface 2 side face each other. When stress along the axial direction is applied to the metal tube 12, the pleat portion 15 can expand and contract while opening or closing between two surfaces facing the top (peak). Further, the inner surface 15s of the pleat portion 15 has a portion that is not joined to the intermediate member 13, and the inner surface 15s of the pleat portion 15 that is not joined to the intermediate member 13 has two surfaces facing the top (peak) as a boundary. It is the inside. In other words, in the intermediate member 13, there is a portion that is not joined to the metal tube 12 in a region sandwiched between the two surfaces of the pleat portion 15. When the intermediate member 13 expands and contracts at the unbonded portion, the metal tube 12 can continue to maintain the bonded state with the intermediate member 13 by changing the degree of opening of the two surfaces of the pleat portion 15.

  In the heat conducting member 10, the pleat portion 15 changes the degree of opening of the two surfaces, thereby suppressing a large stress from being applied from the metal tube 12 to the intermediate material 13 and the cylindrical ceramic body 11. When the intermediate material 13 and the cylindrical ceramic body 11 are stretched, the metal tube 12 itself is also stretched by the action of the pleats 15, so that the stress for contracting the intermediate material 13 and the cylindrical ceramic body 11 is exerted. I'm keeping you from joining. Further, when the intermediate material 13 and the cylindrical ceramic body 11 contract, the metal tube 12 itself contracts by the action of the pleats 15, thereby trying to extend the intermediate material 13 and the cylindrical ceramic body 11. The application of stress is suppressed. As described above, in the present heat conductive member 10, even when the expansion and contraction in the metal tube 12 is different from the expansion and contraction in the cylindrical ceramic body 11 and the intermediate material 13, the metal tube 12 is operated by the function of the folds 15. Since it expands and contracts freely along the axial direction, a large stress is hardly applied from the metal tube 12 to the cylindrical ceramic body 11. As a result, the heat conducting member 10 is less likely to crack or crack in the cylindrical ceramic body 11.

  In the case where the pleat portion 15 protrudes outward as in the metal tube 12 included in the heat conducting member 10, the pleat portion 15 may be one or plural. Further, when there are a plurality of pleat portions 15, there may be a portion that is not joined to the intermediate member 13 on the inner surface of each pleat portion 15. When the number of non-joined portions between the metal tube 12 and the intermediate material 13 increases as described above, the stress relaxation action by the pleats 15 as described above increases, so that the intermediate material 13 and the cylindrical ceramic body 11 from the metal tube 12 are increased. It becomes difficult to apply a large stress to.

  Further, the height of the pleat portion 15 is preferably 0.1 mm to 20 mm, more preferably 1 mm to 10 mm, and particularly preferably 1 mm to 5 mm. Further, the width of the pleat portion 15 is preferably 0.1 mm to 20 mm, more preferably 1 mm to 10 mm, and particularly preferably 1 mm to 5 mm. If the height of the pleat portion 15 and the width of the pleat portion 15 are smaller than 0.1 mm, the stress relaxation action by the pleat portion 15 may not be sufficiently obtained, and if it exceeds 20 mm, the heat conduction efficiency is reduced. It is not preferable. In addition, the height of the pleat portion 15 means the height from the smooth surface of the outer peripheral surface of the metal tube 12 to the top (peak) of the pleat portion 15. Further, the width of the pleat portion 15 means the width of the pleat portion 15 at a position half the height of the pleat portion 15 from the smooth outer peripheral surface of the metal tube 12.

  Further, in the case where the pleat portion 15 protrudes outward like the metal tube 12 provided in the heat conducting member 10, the metal tube 12 has a bellows in which the pleat portion 15 is repeatedly formed along the axial direction. It may be a structure. In the case where the metal tube 12 has a bellows structure, the metal tube 12 can be expanded and contracted even more freely even if the metal tube 12 is kept in the joined state with the intermediate member 13. Thus, when the metal tube 12 has a bellows structure, even when the expansion and contraction in the metal tube 12 is different from the expansion and contraction in the cylindrical ceramic body 11 and the intermediate member 13, the metal tube 12 is cylindrical. It is further suppressed that a large stress is applied to the ceramic body 11, and as a result, cracks and cracks are more unlikely to occur in the cylindrical ceramic body 11.

  In the present heat conductive member 10, the intermediate material 13 can be formed by melting a metal to produce a molten metal, filling the molten metal in a gap between the metal tube 12 and the cylindrical ceramic body 11, and solidifying the molten metal. it can. FIG. 3 is a schematic diagram showing an example of a method for manufacturing the heat conducting member 10, specifically, a method of filling the gap between the metal tube 12 and the cylindrical ceramic body 11 with the molten metal 80. As shown in the drawing, when the molten metal 80 flows into the gap between the metal tube 12 and the cylindrical ceramic body 11, the molten metal 80 is ejected in the longitudinal direction from one end surface 2 in the axial direction to the other end surface 2. By doing so, the molten metal 80 can be filled. At this time, the cylindrical ceramic body 11 was inserted into the metal tube 12 and placed on a table 72 for injecting the molten metal 80 with both end faces 2 of the cylindrical ceramic body 11 closed with lids 71. Thereafter, the molten metal 80 may be injected into the gap between the metal tube 12 and the cylindrical ceramic body 11.

  Further, in the case where the pleat portion 15 protrudes outward like the metal tube 12 provided in the heat conducting member 10, the gap 19 between the inner surface 15s of the pleat portion 15 of the metal tube 12 and the intermediate member 13 is filled. It is also a preferable aspect to provide a material. In particular, when the filler is made of a soft material, the stress relaxation effect by the pleats 15 can be exhibited while maintaining the heat exchange efficiency. Examples of the filler that can be used in the heat conductive member 10 of the present invention include expanded graphite or a material made of ceramic fibers such as alumina, carbon, silica, and the like.

  Next, the form in which the pleats are recessed inward will be described. FIG. 4 is a schematic cross-sectional view of another embodiment of the heat conducting member of the present invention. This figure shows that the present heat conducting member 40 penetrates from one end face 32 to the other end face 32 and has a cylindrical ceramic body 41 having a flow path through which a first fluid as a heating body flows, and a cylindrical ceramic body. And a metal tube 42 fitted to the outer peripheral surface 37h of 41, and an intermediate member 43 joined to the cylindrical ceramic body 41 and the metal tube 42 while being sandwiched between the cylindrical ceramic body 41 and the metal tube 42.

  Further, in the present heat conducting member 40, the metal tube 42 has an annular pleat 45 surrounding the outer periphery of the cylindrical ceramic body 41. The pleat portion 45 is formed by the metal tube 42 being bent inward and recessed. By this pleat 45, the metal tube 42 can expand and contract along the axial direction (the direction connecting the one end face 32 and the other end face 32).

  Further, as shown in the figure, the pleat portion 45 has a groove shape when the heat conducting member 40 is viewed from a cross-section of the cut along the axial direction (the direction in which the central axis 50 extends). The surface (side surface 45s) on the side of one end surface 32 and the surface (side surface 45s) on the side of the other end surface 32 face each other with the bottom of the groove shape as a boundary. When stress along the axial direction acts on the metal tube 42, the pleat 45 can expand and contract while opening or closing between two surfaces (side surfaces 45 s) facing the groove-shaped bottom.

  In the present heat conductive member 40, by changing the degree of opening of the two side surfaces 45s where the groove-shaped pleat portions 45 face each other, it is possible to suppress a large stress from being applied to the intermediate material 43 and the cylindrical ceramic body 41 from the metal tube 42. ing. When the intermediate material 43 and the cylindrical ceramic body 41 are extended, the metal tube 42 itself is extended by the action of the pleats 45, so that a stress for contracting the intermediate material 43 and the cylindrical ceramic body 41 is exerted. I'm keeping you from joining. Further, when the intermediate material 43 and the cylindrical ceramic body 41 contract, the metal tube 12 itself contracts by the action of the pleats 45 so as to extend the intermediate material 43 and the cylindrical ceramic body 41. The application of stress is suppressed. As described above, in the present heat conductive member 40, even when the expansion / contraction magnitude of the metal tube 42 is different from the expansion / contraction magnitude of the cylindrical ceramic body 41 or the intermediate member 43, the metal tube 42 is operated by the function of the fold 45. Since it expands and contracts freely along the axial direction, a large stress is not easily applied from the metal tube 42 to the cylindrical ceramic body 41. As a result, the heat conductive member 40 is less likely to crack or crack in the cylindrical ceramic body 41.

  In the case where the pleat portion 45 is recessed inward as in the metal tube 42 provided in the heat conducting member 40, the pleat portion 45 may be one or plural. When the number of the pleat portions 45 increases, the stress relieving action by the pleat portions 45 as described above increases, so that it is difficult for large stress to be applied from the metal tube 42 to the intermediate member 43 and the cylindrical ceramic body 41.

  Moreover, the depth of the pleat 45 is preferably 0.1 mm to 20 mm, more preferably 1 mm to 10 mm, and particularly preferably 1 mm to 5 mm. Further, the width of the pleat portion 45 is preferably 0.1 mm to 20 mm, more preferably 1 mm to 10 mm, and particularly preferably 1 mm to 5 mm. If the height of the pleat portion 45 and the width of the pleat portion 45 are smaller than 0.1 mm, the stress relaxation action by the pleat portion 45 may not be sufficiently obtained, and if it exceeds 20 mm, the heat conduction efficiency is lowered. It is not preferable. The depth of the pleat portion 45 means the depth from the smooth surface of the outer peripheral surface of the metal tube 42 to the bottom portion of the pleat portion 45. The width of the pleat portion 45 means the width of the pleat portion 45 at a position that is half the depth of the pleat portion 45 from the smooth outer peripheral surface of the metal tube 42.

  In this heat conducting member 40, the intermediate material 43 can be formed by melting a metal to produce a molten metal, filling the molten metal in the gap between the metal tube 12 and the cylindrical ceramic body 11, and solidifying the molten metal. it can. FIG. 5 is a schematic view showing an example of a method for manufacturing the heat conducting member 40, specifically, a method of filling the gap between the metal tube 12 and the cylindrical ceramic body 11 with the molten metal 80. FIG. 6 is a schematic diagram of a B-B ′ cross section in FIG. 5. As shown in the drawing, when the molten metal 80 flows into the gap between the metal tube 42 and the cylindrical ceramic body 41, an inflow port 85 is provided on the side surface of the metal tube 42, and the tube is placed inside the metal tube 42. The molten metal 80 may be injected into the gap between the metal tube 12 and the cylindrical ceramic body 11 from the inlet 85 with the cylindrical ceramic body 11 inserted. In this heat conducting member 40, the bottom of the pleat portion 45 of the metal tube 42 is in contact with the outer peripheral surface 37h of the cylindrical ceramic body, so that the flow of the molten metal 80 is blocked by the pleat portion 45. In such a case, at least one inflow port 85 is provided in each of the regions sandwiched between the folds 45, and the molten metal 80 is inserted into the gap between the metal tube 12 and the cylindrical ceramic body 11 from each inflow port 85. Inject. If a vent is provided in addition to the inlet 85 in the metal pipe 42, air existing in the gap between the metal pipe 12 and the cylindrical ceramic body 11 can be discharged when the molten metal 80 is injected. It becomes easy to pour the molten metal 80.

  Next, the cylindrical ceramic body and the metal tube provided in the heat conducting member of the present invention will be described with reference to FIG. 2 (heat conducting member 10) (Note that the form like the heat conducting member 40 shown in FIG. 4). Also, the contents described below can be applied).

  The cylindrical ceramic body 11 preferably has a thermal conductivity of 100 W / m · K or more. More preferably, it is 120-300 W / m * K, More preferably, it is 150-300 W / m * K. By setting it as this range, heat conductivity becomes favorable and the heat | fever in the cylindrical ceramic body 11 can be discharge | released to the outer side of the metal tube 12 efficiently.

  The cylindrical ceramic body 11 is preferably made of ceramics having excellent heat resistance, and considering heat conductivity in particular, it is preferable that SiC (silicon carbide) having high thermal conductivity is the main component. The main component means that 50% by mass or more of the cylindrical ceramic body 11 is SiC (silicon carbide).

  However, the entire cylindrical ceramic body 11 does not necessarily need to be composed of SiC (silicon carbide), and SiC (silicon carbide) may be included in the main body. That is, the cylindrical ceramic body 11 is preferably made of a ceramic containing SiC (silicon carbide).

  Moreover, even if it is SiC (silicon carbide), in the case of a porous body, high thermal conductivity cannot be obtained. Therefore, it is preferable to impregnate silicon in the process of producing the cylindrical ceramic body 11 to obtain a dense structure. High heat conductivity can be obtained by using a dense structure. For example, in the case of a porous body of SiC (silicon carbide), the thermal conductivity is about 20 W / m · K, but it can be made about 150 W / m · K by using a dense body.

As the cylindrical ceramic body 11, Si-impregnated SiC, (Si + Al) -impregnated SiC, metal composite SiC, recrystallized SiC, Si ₃ N ₄ , SiC, or the like can be adopted, but a high heat exchange rate can be obtained. Si-impregnated SiC and (Si + Al) -impregnated SiC can be employed to obtain a dense structure. Si-impregnated SiC has a structure in which the SiC particle surface is surrounded by solidified metal silicon melt and SiC is joined together through metal silicon, so that silicon carbide is shielded from the atmosphere containing oxygen, preventing oxidation. Is done. Furthermore, SiC has the characteristics of high thermal conductivity and easy heat dissipation, but SiC impregnated with Si is densely formed while exhibiting high thermal conductivity and heat resistance, and has sufficient strength as a heat transfer member. Indicates. That is, the cylindrical ceramic body 11 made of a Si—SiC-based [Si-impregnated SiC, (Si + Al) -impregnated SiC] material has excellent heat resistance, thermal shock resistance, oxidation resistance, and corrosion resistance against acids and alkalis. In addition to showing properties, it exhibits high thermal conductivity.

  The cylindrical ceramic body 11 is formed of ceramics in a cylindrical shape and has a fluid flow path penetrating from one end surface 2 in the axial direction to the other end surface 2. The cylindrical shape is not limited to a cylindrical shape (columnar shape), but may be a prismatic shape having a quadrangular cross section perpendicular to the axial (longitudinal) direction or other polygonal shape.

  FIG. 7 schematically shows an embodiment in which the honeycomb structure 1 in which a large number of cells are formed is used as the cylindrical ceramic body 11. The cylindrical ceramic body 11 is preferably a honeycomb structure 1 that has partition walls 4 and a plurality of cells that serve as fluid flow paths are partitioned by the partition walls 4. By having the partition wall 4, heat from the fluid flowing through the inside of the cylindrical ceramic body 11 can be efficiently collected and transmitted to the outside. The honeycomb structure 1 (tubular ceramic body 11) shown in FIG. 7 has an outer peripheral wall 7 on the outer periphery thereof.

  When the cylindrical ceramic body 11 is formed as the honeycomb structure 1 in which a plurality of cells 3 serving as flow paths are partitioned by the partition walls 4, the cell shape may be a circle, an ellipse, a triangle, a quadrangle, other polygons, etc. A desired shape may be selected as appropriate from the above.

The cell density of the honeycomb structure 1 (that is, the number of cells per unit cross-sectional area) is not particularly limited, and may be appropriately designed according to the purpose, but is 25 to 2000 cells / in 2 (4 to 320 cells / cm ² ) is preferable. When the cell density is smaller than 25 cells / square inch, the strength of the partition walls 4, and consequently the strength of the honeycomb structure 1 itself and the effective GSA (geometric surface area) may be insufficient. On the other hand, if the cell density exceeds 2000 cells / square inch, the pressure loss when the heat medium flows may increase.

  The number of cells per honeycomb structure 1 is preferably 1 to 10,000, and particularly preferably 200 to 2,000. If the number of cells is too large, the honeycomb itself becomes large, so the heat conduction distance from the first fluid side to the second fluid side becomes long, the heat conduction loss becomes large, and the heat flux becomes small. In addition, when the number of cells is small, the heat transfer area on the first fluid side becomes small, the heat resistance on the first fluid side cannot be lowered, and the heat flux becomes small.

  The thickness (wall thickness) of the partition walls 4 of the cells 3 of the honeycomb structure 1 may be appropriately designed according to the purpose, and is not particularly limited. The wall thickness is preferably 50 μm to 2 mm, and more preferably 60 to 500 μm. If the wall thickness is less than 50 μm, the mechanical strength may be reduced, and damage may be caused by impact or thermal stress. On the other hand, if it exceeds 2 mm, there is a possibility that problems such as a decrease in the cell volume ratio on the honeycomb structure side, an increase in fluid pressure loss, and a decrease in the heat exchange rate through which the heat medium permeates may occur.

The density of the partition walls 4 of the cells 3 of the honeycomb structure 1 is preferably 0.5 to ⁵ g / cm ³ . When it is less than 0.5 g / cm ³ , the partition wall 4 has insufficient strength, and the partition wall 4 may be damaged by pressure when the first fluid passes through the flow path. On the other hand, if it exceeds 5 g / cm ³ , the honeycomb structure 1 itself becomes heavy, and the characteristics of weight reduction may be impaired. By setting the density within the above range, the honeycomb structure 1 can be strengthened. Moreover, the effect which improves heat conductivity is also acquired.

  As the metal tube 12, one having heat resistance and corrosion resistance is preferable. For example, a SUS tube, a copper tube, a brass tube, or the like can be used.

  Moreover, about the thickness of the metal pipe 12, 0.1 mm-2 mm are preferable, and 0.15-1.0 mm is more preferable. If it is smaller than 0.1 mm, welding or processing becomes difficult, which may increase the cost. If it is larger than 2 mm, the stress relaxation action by the pleats 15 may not be sufficiently obtained.

  Next, the manufacturing method of the heat conductive member 10 (refer FIG. 7) of one Embodiment of this invention is demonstrated. First, a clay containing ceramic powder is extruded into a desired shape to produce a honeycomb formed body. As the material of the honeycomb structure 1, the above-described ceramics can be used. For example, when manufacturing the honeycomb structure 1 mainly composed of a Si-impregnated SiC composite material, a predetermined amount of C powder, SiC powder, binder Then, water or an organic solvent is kneaded to form a clay and molded to obtain a honeycomb molded body having a desired shape.

  Then, the honeycomb formed body is dried and subjected to Si impregnation firing, whereby the honeycomb structure 1 in which a plurality of cells 3 serving as gas (fluid) flow paths are partitioned by the partition walls 4 can be obtained.

  Subsequently, the metal is melted to produce a molten metal, and this molten metal is filled in the gap between the metal tube 12 and the honeycomb structure 1, and then the molten metal is solidified, so that the intermediate material 13 is made into the metal tube 12 and the honeycomb structure. 1 can be provided. When the molten metal is used as described above, the bonding between the metal tube 12 and the honeycomb structure 1 through the intermediate material 13 can be strengthened. In addition, the molten state referred to in this specification is not only a completely molten state, but also a semi-molten state (a state in which solid is solid-liquid coexistence), a semi-solid state (once a liquid is used once, then it becomes liquid-solid coexistence) Including semi-solids).

  As a method of filling the gap between the metal tube 12 and the honeycomb structure 1 with a molten metal, gravity casting, low pressure casting, die casting (high pressure casting) or the like can be used. Die-casting is excellent in cycle time (cost), and it is easy to fill molten metal in a narrow gap. In addition, the low pressure casting has a long cycle time but is excellent in quality, material yield and the like.

  Alternatively, a brazing material may be used as the intermediate material 13. In this method, the inner surface of the metal tube 12 and the outer peripheral surface 7 h of the honeycomb structure 1 are brazed. The honeycomb structure 1 is covered with a metal tube 12 and a gap between the honeycomb structure 1 and the metal tube 12 is filled with a brazing material. As the brazing material, a silver brazing material, a copper brazing material, a brass brazing material, an aluminum brazing material, a Ni brazing material, or the like can be used. The brazing material can be a paste or a sheet. If it does not enter at room temperature, the metal tube 12 may be warmed. Then, brazing is performed by raising the temperature above the solidus temperature of the brazing material in a vacuum. At that time, the metal tube 12 may be brazed in a state compressed and corrected with a mold from the outside. The brazing material filled in the gap becomes the intermediate material 13 by heating and cooling, and the metal tube 12 and the honeycomb structure 1 are joined.

  In addition, in the case where the pleat portion 15 protrudes to the outside of the metal tube 12, the pleat portion 15 is recessed on the inner surface of the metal tube 12. A filler may be put in the recessed portion in advance, and then the metal tube 12 and the honeycomb structure 1 may be joined via the intermediate material 13. With this method, it is possible to manufacture the heat conducting member 10 including a filler in the gap between the inner surface 15s of the pleat portion 15 of the metal tube 12 and the intermediate member 13.

  FIG. 8 shows a schematic perspective view of an embodiment of the heat exchanger 30 including the heat conducting member 10 of the present invention. As shown in FIG. 8, the heat exchanger 30 is formed by the heat conducting member 10 (honeycomb structure 1 + intermediate material 13 + metal tube 12) and the casing 21 including the heat conducting member 10 inside. The cells 3 of the honeycomb structure 1 of the cylindrical ceramic body 11 serve as the first fluid circulation part 5 through which the first fluid flows. The heat exchanger 30 is configured such that a first fluid having a temperature higher than that of the second fluid flows in the cells 3 of the honeycomb structure 1. In addition, an inlet 22 and an outlet 23 for the second fluid are formed in the casing 21, and the second fluid circulates on the outer peripheral surface 12 h of the metal tube 12 of the heat conducting member 10.

  That is, the second fluid circulation portion 6 is formed by the inner surface 24 of the casing 21 and the outer peripheral surface 12 h of the metal tube 12. The second fluid circulation part 6 is a second fluid circulation part formed by the casing 21 and the outer peripheral surface 12h of the metal tube 12, and includes the first fluid circulation part 5, the partition wall 4 of the honeycomb structure 1, and the intermediate material. 13, which is separated by the metal pipe 12 and can conduct heat, receives heat of the first fluid flowing through the first fluid circulation portion 5 through the partition wall 4, the intermediate material 13, and the metal pipe 12, and circulates the first fluid. Heat is transferred to the heated object which is the second fluid. The first fluid and the second fluid are completely separated, and these fluids are configured not to mix.

  The first fluid circulation portion 5 is formed as a honeycomb structure, and in the case of the honeycomb structure, when the fluid passes through the cell 3, the fluid cannot flow into another cell 3 by the partition wall 4, and the honeycomb structure The fluid travels linearly from one inlet to the outlet. Moreover, the honeycomb structure 1 in the heat exchanger 30 of the present invention is not plugged, so that the heat transfer area of the fluid is increased and the size of the heat exchanger 30 can be reduced. Thereby, the amount of heat transfer per unit volume of the heat exchanger 30 can be increased. Furthermore, since it is not necessary to process the honeycomb structure 1 such as forming plugged portions or forming slits, the heat exchanger 30 can reduce the manufacturing cost.

  It is preferable that the heat exchanger 30 circulates the first fluid having a temperature higher than that of the second fluid and conducts heat from the first fluid to the second fluid. When gas is circulated as the first fluid and liquid is circulated as the second fluid, heat exchange between the first fluid and the second fluid can be performed efficiently. That is, the heat exchanger 30 of the present invention can be applied as a gas / liquid heat exchanger.

  The heating element that is the first fluid to be circulated through the heat exchanger 30 of the present invention having the above configuration is not particularly limited as long as it is a medium having heat. For example, if it is gas, the exhaust gas of a motor vehicle etc. are mentioned. In addition, the medium to be heated, which is the second fluid that takes heat from the heating body (exchanges heat), is not particularly limited as a medium, as long as the temperature is lower than that of the heating body.

  Moreover, when the 1st fluid (high temperature side) distribute | circulated to the heat exchanger 30 (refer FIG. 8) is waste gas, the wall surface (partition wall) inside the cell 3 of the honeycomb structure 1 which a 1st fluid (high temperature side) passes through In 4), a catalyst is preferably supported. This is because in addition to the role of exhaust gas purification, reaction heat (exothermic reaction) generated during exhaust gas purification can also be exchanged. Noble metals (platinum, rhodium, palladium, ruthenium, indium, silver, and gold), aluminum, nickel, zirconium, titanium, cerium, cobalt, manganese, zinc, copper, zinc, tin, iron, niobium, magnesium, lanthanum, samarium, It is preferable to contain at least one element selected from the group consisting of bismuth and barium. These may be metals, oxides, and other compounds.

  The supported amount of the catalyst (catalyst metal + support) supported on the partition walls 4 of the cells 3 of the first fluid circulation part 5 of the honeycomb structure 1 through which the first fluid (high temperature side) passes is 10 to 400 g / It is preferable that it is L, and if it is a noble metal, it is still more preferable that it is 0.1-5 g / L. If the supported amount of the catalyst (catalyst metal + support) is less than 10 g / L, the catalytic action may not be easily exhibited. On the other hand, if it exceeds 400 g / L, the pressure loss increases and the manufacturing cost may increase.

  The heat conducting member of the present invention can be used for heat exchange between a heated body (high temperature side) and a heated body (low temperature side).

1: honeycomb structure, 2: end face (in axial direction), 3: cell, 4: partition, 5: first fluid circulation part, 6: second fluid circulation part, 7: outer peripheral wall, 7h: (tubular ceramics) Of the body, 10: heat conducting member, 11: cylindrical ceramic body, 12: metal tube, 12h: outer surface of (metal tube), 13: intermediate material, 15: pleat portion, 15s: (please portion) ) Inner surface, 19: gap, 20: central axis, 21: casing, 22: inlet of (second fluid), 23: outlet of (second fluid), 24: inner surface of (casing), 30: heat Exchanger, 32: end surface (in the axial direction), 37h: outer peripheral surface (of the cylindrical ceramic body), 40: heat conducting member, 41: cylindrical ceramic body, 42: metal tube, 43: intermediate material, 45: pleats Part, 45s: side surface (of the pleat part), 49: gap, 50: central axis, 71: lid, 72: stand, 80: Yu, 85: inlet.

Claims (2)

A cylindrical ceramic body that has a flow path through which a first fluid that is a heating body flows, from one end face to the other end face;
A metal tube having an annular pleat that fits around the outer peripheral surface of the outer peripheral wall of the cylindrical ceramic body and surrounds the outer periphery of the cylindrical ceramic body;
An intermediate material joined to the cylindrical ceramic body and the metal tube while being sandwiched between the cylindrical ceramic body and the metal tube,
The metal tube has the pleat portion protruding outward,
Having a filler in the gap between the inner surface of the pleated portion of the metal tube and the intermediate material,
The filler is expanded graphite, and the intermediate material is made of a metal formed by casting with a molten metal, or
The filler is an alumina or silica ceramic fiber, and the intermediate material is made of a brazing material,
The first fluid is circulated in the cylindrical ceramic body, the second fluid having a temperature lower than that of the first fluid is circulated on the outer peripheral surface side of the metal tube, and the first fluid and the second fluid are circulated. A heat conduction member that exchanges heat with a fluid.   2. The heat conducting member according to claim 1, wherein the cylindrical ceramic body is a honeycomb structure including partition walls, and a plurality of cells serving as fluid flow paths are defined by the partition walls.

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