Three-phase type honeycomb heater

Abstract

To provide a three-phase type honeycomb heater which improves heat efficiency and heat exchange efficiency.SOLUTION: A three-phase type honeycomb heater comprises: a honeycomb structure 1 including an outer peripheral wall and a partition wall 102 disposed inside of the outer peripheral wall and defining and forming a plurality of cells 101 forming a passage extending from one end face to the other end face; a first electrode which is connectable to a first phase output terminal (R) of a three-phase AC power supply circuit; a second electrode which is connectable to a second phase output terminal (S) of the three-phase AC power supply circuit; and a third electrode which is connectable to a third phase output terminal (T) of the three-phase AC power supply circuit. The honeycomb structure includes: slits 103 disposed so as to specify an electrification path for star-connecting a first electrode 201, a second electrode 202, and a third electrode 203 on the outer peripheral wall and / or the partition wall; and a connection section 104 which mutually connects the first electrode 201, the second electrode 202, and the third electrode 203.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a three-phase honeycomb heater. [Background technology]

[0002] A known conventional three-phase heating element is one made of silicon carbide material. For example, Patent Document 1 (JP 2001-257056 A) describes a three-phase silicon carbide heating element made of cylindrical reaction-sintered silicon carbide with a relative density of 90% or more, characterized in that the heating portion has a structure in which three grooves arranged at 120° intervals are cut spirally, the end portion has a structure in which three grooves arranged at 120° intervals are cut straight, and the electrode portion has a structure in which an insulating refractory material is inserted on the inner diameter side and fixed from the outer diameter side by a metal electrode plate.

[0003] Furthermore, Patent Document 2 (JP 08-250263 A) describes a three-phase silicon carbide heating element which is produced by casting a slurry containing silicon carbide and which includes a heating portion having a central heating portion and two end heating portions, and a tip portion for connecting the central heating portion and the two end heating portions, wherein the tip portion is formed in a W-shape and the central heating portion and the two end heating portions are arranged in one plane.

[0004] As an advantage of three-phase heating elements, for example, Patent Document 1 discloses that "because they can be used directly with a three-phase power source, compared to ordinary single-phase heaters, there is no need for a device to convert to single-phase power, which reduces the cost of the power supply, and it is easier to maintain balance between the phases, which leads to energy savings. In addition, because they are single-terminal type, they can be easily set up by hanging them from the ceiling or side wall of the heating furnace, and they also have the advantage of requiring less wiring capacity."

[0005] On the other hand, it has been proposed to generate heat by passing electricity through a honeycomb structure used as a catalyst carrier, etc. For example, Patent Document 3 (JP-A-07-085952) describes a three-phase honeycomb heater in which a heater body is formed using conductive ceramics as a main component and heater through-holes are provided in the heater body, and the heater body is characterized in that cut grooves are provided in the heater body to change the effective length and effective width of the heater body and thereby change the resistance value. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-257056 [Patent Document 2] Japanese Patent Application Publication No. 08-250263 [Patent Document 3] Japanese Patent Application Publication No. 07-085952 Summary of the Invention [Problem to be solved by the invention]

[0007] The three-phase heating elements disclosed in Patent Documents 1 and 2 have high heat generation efficiency, but do not have a cell flow path structure and therefore have limited heat exchange efficiency. Therefore, there is a need for a three-phase heating element with a structure different from the conventional one.

[0008] The present invention has been completed in view of the above problems, and an object of one embodiment is to provide a three-phase honeycomb heater having high heat generation efficiency and heat exchange efficiency. [Means for solving the problem]

[0009] As a result of intensive research, the present inventors have found that the above-mentioned problems can be solved by providing a plurality of electrodes in a three-phase honeycomb heater having a honeycomb structure and further arranging slits so as to define current paths for connecting a three-phase AC power supply circuit. The present invention has been completed based on the above findings, and is exemplified below.

[0010] Item 1. A honeycomb structure including an outer peripheral wall and partition walls disposed inside the outer peripheral wall and defining a plurality of cells that form flow paths extending from one end face to the other end face; a first electrode connected to the outer wall and connectable to a first phase output terminal (R) of a three-phase AC power supply circuit; a second electrode connected on the outer peripheral wall at a distance from the first electrode and connectable to a second phase output terminal (S) of a three-phase AC power supply circuit; a third electrode on the outer peripheral wall, the third electrode being connected to the first electrode and the second electrode at a distance from each other and connectable to a third-phase output terminal (T) of the three-phase AC power supply circuit; The honeycomb structure a slit arranged in the outer peripheral wall and / or the partition wall so as to define a current path for connecting the first electrode, the second electrode, and the third electrode in a star-shaped connection; a connection portion connecting the first electrode, the second electrode, and the third electrode to one another; A three-phase honeycomb heater equipped with:

[0011] Item 2. A three-phase honeycomb heater according to item 1, wherein the electrical resistances of the three current paths from the connection portion to the outer peripheral wall to which the first electrode, the second electrode, and the third electrode are connected are equal.

[0012] Item 3. A three-phase honeycomb heater according to item 2, wherein the lengths of the three current paths from the connection portion to the outer peripheral wall to which the first electrode, the second electrode, and the third electrode are connected are equal.

[0013] Item 4. The three-phase honeycomb heater according to any one of Items 1 to 3, wherein the honeycomb structure has a first side surface and a second side surface facing the first side surface on the outer wall, the slits extend from the first side surface as a base end toward the second side surface, and the slits extend in a direction parallel to the extension direction of the cells, the connecting portions are disposed on the second side surface side, and the first electrode, the second electrode, and the third electrode are disposed on the first side surface.

[0014] Item 5. The honeycomb structure has a first side surface and a second side surface facing the first side surface on the outer peripheral wall, 4. The three-phase honeycomb heater according to any one of items 1 to 3, wherein the slits extend in the first direction and the second direction, where directions perpendicular to each other in a cross section perpendicular to the cell extension direction are defined as a first direction and a second direction, and the heater has a plurality of slits extending in parallel to the cell extension direction, and the connection portion is disposed inside the honeycomb structure.

[0015] Item 6. A honeycomb structure including an outer peripheral wall and partition walls disposed inside the outer peripheral wall and defining a plurality of cells that form flow paths extending from one end face to the other end face; a first electrode connected to an outer peripheral wall of the honeycomb structure and connectable to a first phase output terminal (R) of a three-phase AC power supply circuit; a second electrode connected to an outer peripheral wall of the honeycomb structure at a distance from the first electrode and connectable to a second phase output terminal (S) of a three-phase AC power supply circuit; a third electrode connected to an outer peripheral wall of the honeycomb structure at a distance from the first electrode and the second electrode, and connectable to a third-phase output terminal (T) of a three-phase AC power supply circuit; a fourth electrode connected to an outer peripheral wall of the honeycomb structure and spaced apart from the first electrode, the second electrode, and the third electrode, and connectable to a first phase output terminal (R) of a three-phase AC power supply circuit; The honeycomb structure A three-phase honeycomb heater having slits arranged in the outer wall and the partition walls to define current paths having a first current path, a second current path, and a third current path for connecting a first electrode, a second electrode, a third electrode, and a fourth electrode in a delta connection.

[0016] Item 7. The three-phase honeycomb heater according to Item 6, wherein the current paths include a first current path between the first electrode and the second electrode, a second current path between the second electrode and the third electrode, and a third current path between the third electrode and the fourth electrode, and the first current path, the second current path, and the third current path have equal electrical resistances.

[0017] Item 8. The three-phase honeycomb heater according to Item 7, wherein the current paths include a first current path between the first electrode and the second electrode, a second current path between the second electrode and the third electrode, and a third current path between the third electrode and the fourth electrode, and the first current path, the second current path, and the third current path have the same length.

[0018] Item 9. The honeycomb structure has a first side surface and a second side surface facing the first side surface on the outer peripheral wall, The slit is When directions orthogonal to each other in a cross section perpendicular to the extension direction of the cell are defined as a first direction and a second direction, a first slit extends along the first direction from the first side surface as a base end and has a tip end on the second side surface side; a second slit spaced apart from the first slit in a second direction, the second slit extending along the first direction with the second side surface as a base end and having a tip end on the first side surface side; Equipped with 9. The three-phase honeycomb heater according to any one of items 6 to 8, wherein the first slits and the second slits are alternately arranged in the second direction in a cross section perpendicular to the cell extension direction, thereby allowing current to alternately flow in the first direction and the second direction along the outer peripheral wall and / or the partition wall.

[0019] Item 10. The honeycomb structure has a first side surface and a second side surface facing the first side surface on the outer peripheral wall, The slit is When directions perpendicular to each other in a cross section parallel to the extension direction of the cell are defined as a first direction and a second direction, a first slit extends along the first direction from the first side surface as a base end and has a tip end on the second side surface side; a second slit spaced apart from the first slit in a second direction in a cross section parallel to the extending direction of the cell, the second slit extending along the first direction with the second side surface as a base end and having a tip on the first side surface side; Equipped with 9. The three-phase honeycomb heater according to any one of items 6 to 8, wherein the first slits and the second slits are alternately arranged in the second direction in a cross section parallel to the cell extension direction, thereby allowing current to alternately flow in the first direction and the second direction along the outer peripheral wall and / or the partition wall.

[0020] Item 11. A three-phase honeycomb heater according to item 9, wherein the first electrode, the second electrode, the third electrode, and the fourth electrode are connected on the first side surface.

[0021] Item 12. A three-phase honeycomb heater according to item 10, wherein the first electrode, the second electrode, the third electrode, and the fourth electrode are connected on the first side surface.

[0022] Item 13. The three-phase honeycomb heater according to Item 9, wherein the first electrode, the second electrode, the third electrode, and the fourth electrode are disposed on the first side surface or the second side surface so that, in a cross section perpendicular to the extension direction of the cells, one current path is defined as a path in which current flows in a first direction along the outer peripheral wall and / or the partition wall, then in a second direction, and then in the first direction, and one or more first current paths, one or more second current paths, and one or more third current paths are provided.

[0023] Item 14. The three-phase honeycomb heater according to Item 10, wherein the first electrode, the second electrode, the third electrode, and the fourth electrode are disposed separately on the first side surface or the second side surface so that, in a cross section parallel to the extension direction of the cells, one current path is defined as a path in which current flows in a first direction along the outer peripheral wall and / or the partition wall, then in a second direction, and then in the first direction, and one or more first current paths, second current paths, and third current paths are provided. [Effects of the Invention]

[0024] According to one embodiment of the present invention, a three-phase honeycomb heater having high heat generation efficiency and heat exchange efficiency can be provided. [Brief explanation of the drawings]

[0025] [Figure 1A]1 is a perspective view showing a honeycomb structure 1 according to one embodiment of the present invention. [Figure 1B] 1B is a cross-sectional view of the honeycomb structure 1 of FIG. 1A taken along a cross section perpendicular to the cell extension direction. [Figure 2A] 1 is a perspective view showing a honeycomb structure 1 according to one embodiment of the present invention. [Figure 2B] 2B is a cross-sectional view of the honeycomb structure 1 of FIG. 2A taken along a cross section perpendicular to the cell extension direction. [Figure 3] 3A and 3B are schematic diagrams showing the structure of a three-phase honeycomb heater 20 according to one embodiment of the present invention. Fig. 3A is a cross-sectional view of the three-phase honeycomb heater 20 when observing a cross section perpendicular to the cell extension direction, and Fig. 3B is a side view of the three-phase honeycomb heater 20 in a direction parallel to the cell extension direction. [Figure 4] Figure 4 is a schematic diagram showing the structure of a three-phase honeycomb heater 30 according to another embodiment of the present invention. Figure 4(A) is a cross-sectional view of the three-phase honeycomb heater 30 when observing a cross section perpendicular to the cell extension direction, and Figure 4(B) is a side view of the three-phase honeycomb heater 30 in a direction parallel to the cell extension direction. [Figure 5] FIG. 5 is a schematic diagram showing three current paths in the three-phase honeycomb heater 30 in the embodiment shown in FIG. [Figure 6] 6A and 6B are schematic diagrams showing the structure of a three-phase honeycomb heater 40 according to another embodiment of the present invention. Fig. 6A is a cross-sectional view of the three-phase honeycomb heater 40 when observing a cross section perpendicular to the cell extension direction, and Fig. 6B is a side view of the three-phase honeycomb heater 40 in a direction parallel to the cell extension direction. [Figure 7] FIG. 7 is a schematic diagram showing three current paths in the three-phase honeycomb heater 40 in the embodiment shown in FIG. 6. [Figure 8] 8A and 8B are schematic diagrams showing the structure of a three-phase honeycomb heater 50 according to one embodiment of the present invention. Fig. 8A is a cross-sectional view of the three-phase honeycomb heater 50 when observing a cross section perpendicular to the extension direction of the cells 102, and Fig. 8B is a side view of the three-phase honeycomb heater 50 in a direction parallel to the extension direction of the cells 102. [Figure 9] 9A and 9B are schematic diagrams showing the structure of a three-phase honeycomb heater 60 according to another embodiment of the present invention. Fig. 9A is a cross-sectional view of the three-phase honeycomb heater 60 when observing a cross section perpendicular to the cell extension direction, and Fig. 9B is a side view of the three-phase honeycomb heater 60 in a direction parallel to the cell extension direction. [Figure 10] 10A and 10B are schematic diagrams showing the structure of a three-phase honeycomb heater 70 according to still another embodiment of the present invention. Fig. 10A is a cross-sectional view of the three-phase honeycomb heater 70 when observing a cross section perpendicular to the cell extension direction, and Fig. 10B is a side view of the three-phase honeycomb heater 70 in a direction parallel to the cell extension direction. [Figure 11] 11A and 11B are schematic diagrams showing the structure of a three-phase honeycomb heater 70 according to still another embodiment of the present invention. Fig. 11A is a cross-sectional view of the three-phase honeycomb heater 80 when observing a cross section perpendicular to the extension direction of the cells 102, and Fig. 11B is a side view of the three-phase honeycomb heater 80 in a direction parallel to the extension direction of the cells 102. [Figure 12] 12A and 12B are schematic diagrams showing the structure of a three-phase honeycomb heater 70 according to still another embodiment of the present invention. Fig. 12A is a cross-sectional view of a three-phase honeycomb heater 90 taken along a line perpendicular to the cell extension direction, and Fig. 12B is a side view of the three-phase honeycomb heater 90 taken along a line parallel to the cell extension direction. [Figure 13] 13A and 13B are schematic diagrams showing the structure of a three-phase honeycomb heater 21 according to still another embodiment of the present invention. Fig. 13A is a cross-sectional view of the three-phase honeycomb heater 21 when observing a cross section perpendicular to the cell extension direction, and Fig. 13B is a side view of the three-phase honeycomb heater 21 in a direction parallel to the cell extension direction. DETAILED DESCRIPTION OF THE INVENTION

[0026] Next, embodiments of the present invention will be described in detail with reference to the drawings. It should be understood that the present invention is not limited to the following embodiments, and that appropriate design changes and improvements may be made based on the ordinary knowledge of those skilled in the art without departing from the spirit of the present invention.

[0027] (1. Honeycomb structure) Fig. 1A is a perspective view showing a honeycomb structure 1 that can be used in one embodiment of the present invention. Fig. 1B is a cross-sectional view of the honeycomb structure 1 of Fig. 1A when a cross section perpendicular to the cell extension direction is observed. Fig. 2A is a perspective view showing a honeycomb structure 1 that can be used in another embodiment of the present invention. Fig. 2B is a cross-sectional view of the honeycomb structure 1 of Fig. 2A when a cross section perpendicular to the cell extension direction is observed.

[0028] The honeycomb structure 1 includes a peripheral wall 100, partition walls 101 disposed inside the peripheral wall 100 to define a plurality of cells 102 that form flow paths extending from one end face to the other end face, and a plurality of slits 103 arranged apart from each other in a cross section perpendicular to the extension direction of the cells 102 so as to restrict current paths between the peripheral wall 100 and each other. From the viewpoint of maintaining the strength of the honeycomb structure 1, the thickness of the peripheral wall 100 is preferably greater than the thickness of the partition walls 101.

[0029] 1A and 1B, in a cross section of the honeycomb structure 1 perpendicular to the extension direction of the cells 102, when directions orthogonal to each other are a first direction (FD, vertical direction in the drawing) and a second direction (SD, horizontal direction in the drawing), the honeycomb structure 1 includes a plurality of slits 103, each of which includes a first slit 103a having a base end at one end in the first direction FD and a tip end at the other end, and a second slit 103b spaced apart from the first slit 103a in the second direction SD and having a base end at the other end in the first direction FD and a tip end at the one end. In the illustrated embodiment, three first slits 103a and two second slits 103b are provided.

[0030] 2A and 2B, in a cross section of the honeycomb structure 1 parallel to the extension direction of the cells 102, when directions perpendicular to each other are defined as a first direction (FD, vertical direction in the drawings) and a second direction (SD, horizontal direction in the drawings), the honeycomb structure 1 includes a plurality of slits 103, each of which includes a first slit 103a having a base end at one end in the first direction FD and a tip end at the other end, and a second slit 103b spaced apart from the first slit 103a in the second direction SD and having a base end at the other end in the first direction FD and a tip end at the one end. In the illustrated embodiment, three first slits 103a and two second slits 103b are provided.

[0031] The ratio of the length in the first direction FD of each slit 103 to the length in the first direction FD from the tip of each slit 103 to the outer surface of the peripheral wall 100 on the other end side of the honeycomb structure 1 is preferably 3:1 or more, more preferably 6:1 or more, and even more preferably 9:1 or more, from the viewpoint of improving uniform heat generation. Furthermore, from the viewpoint of ensuring the mechanical strength of the honeycomb structure 1, the ratio is preferably 18:1 or less, more preferably 15:1 or less, and even more preferably 12:1 or less. Therefore, the ratio is, for example, preferably 3 to 18:1, more preferably 6 to 15:1, and even more preferably 9 to 12:1.

[0032] The honeycomb structure 1 is restricted by the first slits 103a and the second slits 103b, and thus a current path is formed for connecting with a predetermined wire when a current is applied to the honeycomb structure 1. The current path will be described in detail later.

[0033] 1A and 1B and 2A and 2B, the first slits 103a and the second slits 103b are arranged parallel to each other and spaced apart equally in the second direction SD. The first slits 103a and the second slits 103b are arranged alternately in the second direction SD. The first slits 103a and the second slits 103b have the same length in the first direction FD. However, in other embodiments of the present invention, the location, direction, and length of the slits 103 may be changed. This will be explained in more detail below.

[0034] The shape of the cells 102 of the honeycomb structure 1 is not particularly limited, and may be polygonal (such as a square, pentagon, hexagon, heptagon, or octagon), circular, or oval in a cross section perpendicular to the extension direction of the cells 102. These shapes may be a single shape or a combination of two or more shapes. Among these shapes, a square or hexagon is preferable. By providing cells 102 with such a shape, it is possible to reduce pressure loss during air circulation. Note that FIGS. 1 and 2 show an example of a honeycomb structure 1 in which the outer shape of the cross section and the shape of the cells 102 are square in a cross section perpendicular to the extension direction of the cells 102.

[0035] The thickness of the partition walls 101 that separate the cells 102 is not particularly limited, but is, for example, 70 μm to 500 μm. The number of the cells 102 in a cross section perpendicular to the extending direction of the cells 102 is not particularly limited, but is, for example, 15 cells / cm 2 ~150 cells / cm 2 The thickness of the partition wall 101 refers to the length of a line segment that crosses the partition wall 101 when the line segment connects the centers of gravity of adjacent cells 102 in a cross section perpendicular to the extension direction of the cells 102. The thickness of the partition wall 101 and the number of cells 102 can be measured using, for example, a digital microscope.

[0036] The aperture ratio of the honeycomb structure 1 is not particularly limited, but is, for example, 65 to 90%. Here, the aperture ratio of the honeycomb structure 1 refers to the ratio of the aperture area per unit area in a cross section perpendicular to the extension direction of the cells 102 of the honeycomb structure 1. Specifically, the aperture ratio of the honeycomb structure 1 is the ratio of the total aperture area of ​​the cells 102 to the total area of ​​the cross section perpendicular to the extension direction of the cells 102 of the honeycomb structure 1 (including the partition walls 101, the openings of the cells 102, the slits 103, and the outer peripheral wall 100; if electrodes or electrode layers described below are provided, these are not taken into consideration). The aperture ratio of the honeycomb structure 1 can be measured, for example, using a digital microscope.

[0037] The hydraulic diameter of the cells 102 of the honeycomb structure 1 is, for example, 0.7 mm to 1.8 mm. Here, the hydraulic diameter of the cells 102 of the honeycomb structure 1 is calculated by multiplying the perimeter (unit: mm) surrounded by the partition walls 101 and the cross-sectional area of ​​the cells 102 (unit: mm 2 ) and is calculated by the formula: 4×(cross-sectional area) / (perimeter). The perimeter surrounded by the partition walls 101 and the cross-sectional area of ​​the cell 102 can be measured by, for example, a digital microscope.

[0038] In the embodiment shown in FIGS. 1, 2A, and 2B, the shape of the peripheral wall 100 in a cross section perpendicular to the extension direction of the cells 102 is rectangular, but it may be other polygonal shapes, circular, or other shapes. The thickness of the peripheral wall 100 is, for example, 0.5 mm to 5 mm. A heating element can be formed by electrically connecting a plurality of honeycomb structures 1 having different shapes and sizes. Here, the thickness of the peripheral wall 100 is defined as the thickness in the direction normal to the tangent of the peripheral wall 100 at a measurement point when the portion of the peripheral wall 100 whose thickness is to be measured is observed in a cross section perpendicular to the extension direction of the cells 102. The thickness of the peripheral wall 100 can be measured, for example, using a digital microscope.

[0039] The difference between the average thickness of the outer peripheral wall 100 and the average thickness of the partition walls 101 can be, for example, 100 to 1200 μm, and typically 200 to 800 μm. The average thickness of the outer peripheral wall 100 refers to the average value when the thickness of the outer peripheral wall 100 is measured at 10 positions without bias. The average thickness of the partition walls 101 refers to the average value when the thickness of the partition walls 101 is measured at 10 positions without bias.

[0040] The volume resistivity of the honeycomb structure 1 is, for example, 0.001 Ω·cm or more, preferably 0.01 Ω·cm or more, and more preferably 0.1 Ω·cm or more. Such a volume resistivity can suppress problems such as excessive current flow depending on the applied voltage. On the other hand, the volume resistivity of the honeycomb structure 1 is, for example, 200 Ω·cm or less, and preferably 100 Ω·cm or less. Such a volume resistivity can generate sufficient heat when current is applied. The volume resistivity is a value measured at 25°C using a four-terminal method.

[0041] The honeycomb structure 1 may be mainly composed of ceramics. Preferably, the honeycomb structure 1 is mainly composed of conductive ceramics. When the honeycomb structure 1 is mainly composed of ceramics, it means that the honeycomb structure 1 contains 80 mass % or more, preferably 90 mass % or more, of ceramics as a whole. The ceramics may be selected from the group consisting of oxide ceramics such as alumina, mullite, zirconia, and cordierite, and non-oxide ceramics such as silicon carbide (SiC), silicon nitride, and aluminum nitride. Examples of conductive ceramics include metal compounds such as metal silicides such as silicon carbide, tantalum silicide (TaSi2), and chromium silicide (CrSi2).

[0042] In one embodiment, the honeycomb structure 1 is made of a material containing silicon carbide. The honeycomb structure 1 is preferably made of a material containing a silicon carbide material or a carbon-silicon carbide composite material as a main component. When the honeycomb structure 1 is said to contain a silicon carbide material or a carbon-silicon carbide composite material as a main component, it means that the honeycomb structure 1 contains 80 mass % or more, preferably 90 mass % or more of the silicon carbide material or the carbon-silicon carbide composite material as a whole.

[0043] The silicon carbide material may be a material impregnated with silicon (silicon-impregnated silicon carbide). The silicon-silicon carbide composite material may be a material in which multiple silicon carbide particles are bonded together by metallic silicon. In the silicon-silicon carbide composite material, the silicon carbide particles may function as aggregate, and the silicon may function as a binder. By using such a material, the above-mentioned volume resistivity can be satisfactorily achieved. The volume resistivity of the honeycomb structure 1 can also be controlled by adjusting its porosity.

[0044] The honeycomb structure 1 can be obtained by drying and firing a formed body obtained by forming a forming material containing ceramic raw materials. When the honeycomb structure 1 is made of the silicon-silicon carbide composite material, the forming material can contain silicon carbide (e.g., silicon carbide powder) and metallic silicon (e.g., metallic silicon powder). Examples of other raw materials that can be contained in the forming material include a binder, a dispersion medium, and an additive.

[0045] Typically, the honeycomb structure 1 can be used as a catalyst carrier, and a catalyst can be supported on the partition walls 101. For example, CO, NO, etc. in a fluid (e.g., gas) passing through the cells 102 x It is possible to convert hydrocarbons and the like into harmless substances through a catalytic reaction. The catalyst may preferably contain a noble metal (e.g., platinum, rhodium, palladium, ruthenium, indium, silver, gold), aluminum, nickel, zirconium, titanium, cerium, cobalt, manganese, zinc, copper, tin, iron, niobium, magnesium, lanthanum, samarium, bismuth, barium, and combinations thereof.

[0046] (2. Three-phase honeycomb heater: star-type connection) Fig. 3 is a schematic diagram showing the structure of a three-phase honeycomb heater 20 according to one embodiment of the present invention. Fig. 3(A) is a cross-sectional view of the three-phase honeycomb heater 20 when observing a cross section perpendicular to the extension direction of the cells 102, and Fig. 3(B) is a side view of the three-phase honeycomb heater 20 in a direction parallel to the extension direction of the cells 102.

[0047] In the embodiment shown in FIG. 3, the three-phase honeycomb heater 20 has: A honeycomb structure (1) including an outer peripheral wall (100) and partition walls (101) disposed inside the outer peripheral wall (100) and defining a plurality of cells (102) that form flow paths extending from one end face to the other end face; a first electrode 201 connected to the outer peripheral wall 100 and connectable to a first phase output terminal (R) of a three-phase AC power supply circuit (not shown); a second electrode 202 connected on the outer peripheral wall 100 at a distance from the first electrode 201 and connectable to a second phase output terminal (S) of a three-phase AC power supply circuit; a third electrode 203 connected on the outer peripheral wall 100 and spaced apart from the first electrode 201 and the second electrode 202, and connectable to a third phase output terminal (T) of a three-phase AC power supply circuit; The honeycomb structure 1 is a slit 103 arranged in the outer peripheral wall 100 and / or the partition wall 101 so as to define a current path (in the direction of the arrow in the drawing) for connecting the first electrode 201, the second electrode 202, and the third electrode 203 in a star-shaped wiring configuration; and a connection portion 104 that connects the first electrode 201, the second electrode 202, and the third electrode 203 to one another.

[0048] The honeycomb structure 1 has an outer wall 100 having a first side surface 105 and a second side surface 106 opposite to the first side surface 105, and has a plurality of slits 103 extending from the first side surface 105 as a base end toward the second side surface 106 and extending in a direction parallel to the extension direction of the cells 102, a connection portion 104 arranged on the second side surface 106 side, and a first electrode 201, a second electrode 202, and a third electrode 203 arranged on the first side surface 105.

[0049] The configuration of the three-phase AC power supply circuit is not particularly limited, and any general three-phase AC power supply circuit can be used. By connecting the first electrode 201, the second electrode 202, and the third electrode 203, which are spaced apart from each other, on the outer peripheral wall 100, a so-called star-connected current path is formed, and a connection portion 104 is formed where these electrodes are electrically connected to each other. By transmitting power using a three-phase AC power supply circuit, the power that can be transmitted per unit time is increased (ideally by √3 times) compared to when a conventional single-phase AC power supply circuit is used, thereby significantly improving heat generation efficiency. Furthermore, since the honeycomb structure 1 is configured as a heating element, the heat exchange area is significantly increased compared to conventional silicon carbide heating elements, resulting in high heat exchange efficiency. Therefore, when configured as a heater, there is also the advantage that it can be made smaller than conventional heaters.

[0050] The current paths indicated by arrows in the drawing are intended to roughly show the current flow, and in reality, current flows through all of the outer peripheral walls 100 and partition walls 101. The connection portions 104 are naturally formed by passing current through the honeycomb structure 1, and do not need to be made of a material or have a structure different from that of the other portions. The first electrode 201, the second electrode 202, and the third electrode 203 can be connected to the first-phase output terminal (R), the second-phase output terminal (S), and the third-phase output terminal (T) of the three-phase AC power supply circuit in any combination, and are not necessarily limited to the combinations shown in the drawing. These explanations are similarly applicable to other embodiments of the present invention.

[0051] From the viewpoint of more uniform heat generation during current flow, it is preferable that the electrical resistances of the three current paths from the connection part 104 to the outer peripheral wall 100 to which the first electrode 201, the second electrode 202, and the third electrode 203 are connected are equal. The electrical resistance of the current paths can be adjusted by changing the length of each current path, the cross-sectional area of ​​the surface perpendicular to the current flow direction, and the material.

[0052] Similarly, from the viewpoint of more uniform heat generation during current flow, it is preferable that the lengths of the three current paths from the connection portion 104 to the outer peripheral wall 100 to which the first electrode 201, the second electrode 202, and the third electrode 203 are connected are equal. When the honeycomb structure 1 has a homogeneous composition and the cross-sectional areas of the faces perpendicular to the current flow direction are equal, the fact that the lengths of the three current paths are equal also means that the electrical resistances of the current paths are equal, making it easier to achieve uniform heat generation.

[0053] In this specification, the length of the current-carrying path refers to the length of the center line of each current-carrying path from the first electrode 201, the second electrode 202, and the third electrode 203 to the connection portion 104. When the geometric shapes of the portions of the honeycomb structure 1 constituting each current-carrying path are identical or symmetrical, the lengths of the current-carrying paths may be considered to be equal. Furthermore, the term "equal" in the length of the current-carrying path means that the length of each current-carrying region is within a range of ±10% of the average length of all the current-carrying paths. The electrical resistance of each current-carrying path is a value measured at 25°C using a four-terminal method.

[0054] 3(A) and 3(B), the current path from the connection portion 104 to the outer peripheral wall 100 to which the second electrode 202 is connected is considered to be slightly shorter than the other two current paths. Other embodiments of star-shaped connections will be described below by way of example.

[0055] The first electrode 201, the second electrode 202, and the third electrode 203 may each be formed as an electrode terminal. When the honeycomb structure 1 is viewed from the extension direction of the cells 102, the first electrode 201, the second electrode 202, and the third electrode 203 are disposed at the center of the honeycomb structure 1. However, the first electrode 201, the second electrode 202, and the third electrode 203 may be disposed on one side or both sides of the center of the honeycomb structure 1. Note that, in order to equalize the electrical resistance of each current path and improve heat generation uniformity, the first electrode 201, the second electrode 202, and the third electrode 203 are preferably connected to the end of each current path. In the example of FIG. 3, the first electrode 201, the second electrode 202, and the third electrode 203 are preferably connected to the first side surface 105 so as to be as close as possible to the base ends of the three current paths separated by the two slits 103.

[0056] In the illustrated example, cylindrical electrode terminals are provided as the first electrode 201, the second electrode 202, and the third electrode 203, but the shape and size of the electrode terminals are not particularly limited. For example, the electrode terminals may be shaped like a rectangular pillar or comb teeth. Although not illustrated, the first electrode 201, the second electrode 202, and the third electrode 203 may be configured by forming an electrode layer on the outer wall 100 of the honeycomb structure 1 and providing the electrode terminals via this electrode layer. The thickness of the electrode layer is, for example, 100 μm to 5 mm.

[0057] The volume resistivity of the first electrode 201, the second electrode 202, and the third electrode 203 varies depending on their configuration and materials, but the lower the volume resistivity, the better, and is typically 0.01 Ω cm or less. The volume resistivity is a value measured at 25°C by the four-terminal method.

[0058] The first electrode 201, the second electrode 202, and the third electrode 203 may be made of any appropriate material. Examples of materials that can be used for the first electrode 201, the second electrode 202, and the third electrode 203 include metals, conductive ceramics, and composites (cermets) of metals and conductive ceramics. Examples of metals include Cr, Fe, Co, Ni, Si, and Ti. These may be used alone or in combination of two or more. When two or more types are used in combination, an alloy of two or more metals may be used. Examples of conductive ceramics include metal compounds such as silicon carbide, metal silicides such as tantalum silicide (TaSi2), and chromium silicide (CrSi2). Specific examples of composites (cermets) of metals and conductive ceramics include composites of metal silicon and silicon carbide, and composites of the above metal silicides, metal silicon, and silicon carbide. Specific examples of composites (cermets) of metals and conductive ceramics include composites in which one or more of the above metals are added with one or more insulating ceramics such as alumina, mullite, zirconia, cordierite, silicon nitride, and aluminum nitride, from the viewpoint of reducing thermal expansion.

[0059] When the electrode terminals constituting the first electrode 201, the second electrode 202, and the third electrode 203 are made of a metal, the electrode terminals preferably have a comb-like shape. When the electrode terminals are made of a conductive ceramic or a composite material (cermet) of a metal and a conductive ceramic, the electrode terminals preferably have a cylindrical or rectangular columnar shape. When the electrode terminals are made of a conductive ceramic or a composite material (cermet) of a metal and a conductive ceramic, metal parts may be joined to both ends of the electrode terminals. The ceramic electrode terminals and the metal parts can be joined by, for example, crimping, welding, or using a conductive adhesive. Examples of materials for the metal parts include conductive metals such as iron alloys and nickel alloys.

[0060] It is preferable that at least a part of the first electrode 201, the second electrode 202, and the third electrode 203 is made of the same material as that of the honeycomb structure 1. With such a configuration, the difference in thermal expansion coefficient between the honeycomb structure 1 and the first electrode 201, the second electrode 202, and the third electrode 203 can be reduced, thereby increasing the bonding strength therebetween. This can also contribute to improving productivity. The volume resistivity of the first electrode 201, the second electrode 202, and the third electrode 203 can also be controlled by adjusting their porosity.

[0061] The above description of electrodes and electrode layers may also be applied to other embodiments of the present invention.

[0062] Figure 4 is a schematic diagram showing the structure of a three-phase honeycomb heater 30 according to another embodiment of the present invention. Figure 4(A) is a cross-sectional view of the three-phase honeycomb heater 30 when observing a cross section perpendicular to the cell extension direction, and Figure 4(B) is a side view of the three-phase honeycomb heater 30 in a direction parallel to the cell extension direction. Note that enlarged views of the partition walls and cells are omitted.

[0063] The honeycomb structure 1 has a first side surface 105 and a second side surface 106 facing the first side surface 105 on the peripheral wall 100, and when directions perpendicular to each other in a cross section perpendicular to the cell extension direction are defined as a first direction FD and a second direction SD, the honeycomb structure 1 has a plurality of slits 103 extending in the first direction FD and the second direction SD and extending parallel to the cell extension direction, and connection portions 104 are arranged inside the honeycomb structure 1. That is, each of the plurality of slits 103 has both a portion extending in the first direction FD and a portion extending in the second direction SD, and the connection portions 104 are inside the honeycomb structure 1 and are separated from the peripheral wall 100.

[0064] 4, three slits 103 are arranged in a spiral shape, and a first electrode 301, a second electrode 302, and a third electrode 303 are arranged near the base end of each slit 103. As a result, the first electrode 301 and the second electrode 302 are arranged on the second side surface 106 of the honeycomb structure 1, and the third electrode 303 is arranged on the first side surface 105 of the honeycomb structure 1.

[0065] FIG. 5 is a schematic diagram showing three current paths in the three-phase honeycomb heater 30 in the embodiment shown in FIG. 4. If the intersection of the three current paths formed by the three slits 103 is defined as a connection 104, current paths are formed from the first electrode 301, the second electrode 302, and the third electrode 303 to the connection 104 in the order of the circled numbers 1 to 8. These current paths are connected by black lines in FIG. 5 for ease of understanding. However, as described above, in reality, current flows through all of the outer peripheral walls 100 and partition walls 101. Therefore, when referring to the length of a current path in the first embodiment, this length refers to the length of the center line of each current path from the contact portion between each electrode and the honeycomb structure 1 to the connection 104. Furthermore, when the geometric shapes of the portions of the honeycomb structure 1 constituting each current path are identical or symmetrical, the lengths of the current paths may be considered to be equal. It should be noted that the notation of each cell in FIG. 5 is conceptual, and the honeycomb structure 1 is not actually configured in a divided manner.

[0066] Fig. 6 is a schematic diagram showing the structure of a three-phase honeycomb heater 40 according to yet another embodiment of the present invention. Fig. 6(A) is a cross-sectional view of the three-phase honeycomb heater 40 when observing a cross section perpendicular to the cell extension direction, and Fig. 6(B) is a side view of the three-phase honeycomb heater 40 in a direction parallel to the cell extension direction. Note that enlarged views of the partition walls and cells are omitted.

[0067] The honeycomb structure 1 has a first side surface 105 and a second side surface 106 facing the first side surface 105 on the peripheral wall 100, and when directions perpendicular to each other in a cross section perpendicular to the cell extension direction are defined as a first direction FD and a second direction SD, the honeycomb structure 1 has a plurality of slits 103 extending in the first direction FD and the second direction SD and extending parallel to the cell extension direction, and connection portions 104 are arranged inside the honeycomb structure 1. That is, each of the plurality of slits 103 has both a portion extending in the first direction FD and a portion extending in the second direction SD, and the connection portions 104 are inside the honeycomb structure 1 and are separated from the peripheral wall 100.

[0068] 6, three slits 103 are arranged in a spiral shape, and a first electrode 401, a second electrode 402, and a third electrode 403 are arranged near the base end of each slit 103. As a result, the first electrode 401 and the second electrode 402 are arranged on the second side surface 106 of the honeycomb structure 1, and the third electrode 403 is arranged on the first side surface 105 of the honeycomb structure 1.

[0069] FIG. 7 is a schematic diagram showing three current paths in the three-phase honeycomb heater 40 in the embodiment shown in FIG. 6. If the intersection of the three current paths formed by the three slits 103 is defined as a connection portion 104, current paths are formed from the first electrode 401, the second electrode 402, and the third electrode 403 to the connection portion 104 in the order of the circled numbers 1 to 16. For ease of understanding, these current paths are connected by black lines in FIG. 7, but as described above, in reality, current flows through all of the outer peripheral walls 100 and partition walls 101. It should be noted that the notation of each cell in FIG. 7 is conceptual and does not actually indicate that the honeycomb structure 1 is divided into sections.

[0070] (3. Three-phase honeycomb heater: Delta connection) Fig. 8 is a schematic diagram showing the structure of a three-phase honeycomb heater 50 according to one embodiment of the present invention. Fig. 8(A) is a cross-sectional view of the three-phase honeycomb heater 50 when observing a cross section perpendicular to the extension direction of the cells 102, and Fig. 8(B) is a side view of the three-phase honeycomb heater 50 in a direction parallel to the extension direction of the cells 102.

[0071] In the embodiment shown in FIG. 8, the three-phase honeycomb heater 50 has: A honeycomb structure (1) including an outer peripheral wall (100) and partition walls (101) disposed inside the outer peripheral wall (100) and defining a plurality of cells (102) that form flow paths extending from one end face to the other end face; a first electrode 501 connected to an outer peripheral wall of the honeycomb structure 1 and connectable to a first phase output terminal (R) of a three-phase AC power supply circuit; a second electrode 502 connected to the outer peripheral wall 100 of the honeycomb structure 1 at a distance from the first electrode 501 and connectable to a second phase output terminal (S) of a three-phase AC power supply circuit; a third electrode 503 connected to the outer peripheral wall 100 of the honeycomb structure 1 at a distance from the first electrode 501 and the second electrode 502, and connectable to a third phase output terminal (T) of a three-phase AC power supply circuit; a fourth electrode 504 connected to the outer peripheral wall 100 of the honeycomb structure 1 at a distance from the first electrode 501, the second electrode 502, and the third electrode 503, and connectable to a first phase output terminal (R) of a three-phase AC power supply circuit; The honeycomb structure 1 is The device is provided with slits 103 arranged in the outer wall 100 and the partition wall 101 to define a current path having a first current path 5012, a second current path 5023, and a third current path 5034 for connecting the first electrode 501, the second electrode 502, the third electrode 503, and the fourth electrode 504 in a delta-type wiring.

[0072] The honeycomb structure 1 has a first side surface 105 and a second side surface 106 opposite the first side surface 105 on the outer wall 100, and the slits 103 have a first slit 103a that extends along the first direction FD from the first side surface 105 and has a tip on the second side surface side, when the directions perpendicular to each other in a cross section perpendicular to the extension direction of the cells 102 are defined as a first direction FD and a second direction SD, and a second slit 103b that is spaced apart from the first slit 103a in the second direction SD, extends along the first direction FD from the second side surface 106 and has a tip on the first side surface 105 side, and the first slits 103a and the second slits 103b are arranged alternately in the second direction SD in the cross section perpendicular to the extension direction of the cells 102, thereby allowing current to flow alternately in the first direction FD and the second direction SD along the outer wall 100 and / or the partition wall 101.

[0073] In the embodiment shown in Fig. 8, the first slits 103a and the second slits 103b are arranged parallel to each other and at equal intervals in the second direction SD. The first slits 103a and the second slits 103b are arranged alternately in the second direction SD. The first slits 103a and the second slits 103b have the same length in the first direction FD. In the embodiment shown in Fig. 8, three first slits 103a and two second slits 103b are provided.

[0074] 8, the first electrode 501, the second electrode 502, the third electrode 503, and the fourth electrode 504 are connected on the first side 105. In other embodiments of the invention, the first electrode 501, the second electrode 502, the third electrode 503, and the fourth electrode 504 may be connected on the second side 106.

[0075] The configuration of the three-phase AC power supply circuit is not particularly limited, and any known three-phase AC power supply circuit can be used. A first electrode 501, a second electrode 502, a third electrode 503, and a fourth electrode 504, which are spaced apart from one another, are connected to the outer peripheral wall 100, forming a current path with a so-called delta connection. By transmitting power using a three-phase AC power supply circuit, the amount of power that can be transmitted per unit time increases (by √3 times in an ideal state) compared to when a conventional single-phase AC power supply circuit is used, resulting in a significant improvement in heat generation efficiency. Furthermore, since the honeycomb structure 1 is configured as a heating element, the heat exchange area is significantly increased compared to conventional silicon carbide heating elements, resulting in high heat exchange efficiency. Therefore, when configured as a heater, it has the advantage of being more compact than conventional heaters.

[0076] The star-type connection applied in the first embodiment of the present invention essentially becomes a single-phase AC power supply circuit (i.e., the output drops to 1 / 2) when one of the three phases is damaged and cannot be energized, but the delta-type connection provided in the second embodiment of the present invention can maintain 2 / 3 of the original output even when one of the three phases is damaged and cannot be energized. Therefore, the second embodiment of the present invention is more preferable in that it can generate heat at a relatively high output even when part of the three-phase AC power supply circuit fails.

[0077] The first current path 5012, the second current path 5023, and the third current path 5034 indicated by arrows in the drawing are intended to roughly indicate the current flow, and in reality, current flows through all of the outer peripheral walls 100 and the partition walls 101. The first electrode 501, the second electrode 502, and the third electrode 503 can be connected in any combination to the first-phase output terminal (R), the second-phase output terminal (S), and the third-phase output terminal (T) of the three-phase AC power supply circuit, and the first electrode 501 and the fourth electrode 504 are not necessarily limited to the combinations shown in the drawing, as long as they are connected to the same output terminal. These explanations apply similarly to other embodiments of the present invention.

[0078] From the viewpoint of more uniform heat generation during current flow, when the current paths are a first current path 5012 between the first electrode 501 and the second electrode 502, a second current path 5023 between the second electrode 502 and the third electrode 503, and a third current path 5034 between the third electrode 503 and the fourth electrode 504, it is preferable that the electrical resistances of the first current path 5012, the second current path 5023, and the third current path 5034 are equal. The electrical resistance of the current paths can be adjusted by changing the length of each current path, the cross-sectional area of ​​the surface perpendicular to the current flow direction, and the material of each current path.

[0079] Similarly, from the viewpoint of achieving more uniform heat generation during current application, when the current paths are a first current path 5012 between the first electrode 501 and the second electrode 502, a second current path 5023 between the second electrode 502 and the third electrode 503, and a third current path 5034 between the third electrode 503 and the fourth electrode 504, it is preferable that the lengths of the first current path 5012, the second current path 5023, and the third current path 5034 are equal. When the honeycomb structure 1 has a homogeneous composition and the cross-sectional areas of the surfaces perpendicular to the current application direction are equal, the equal lengths of the three current paths also mean that the electrical resistances of the current paths are equal, which facilitates uniform heat generation. These current paths are indicated by arrows in FIG. 8 for ease of understanding. However, as described above, in reality, current flows through all of the outer peripheral wall 100 and the partition walls 101. Therefore, in the second embodiment, when referring to the length of the current path, the length of the current path refers to the length of the center line of each current path, and can include the length of each current path being within ±10% of the average length of all the current paths. Furthermore, if the geometric shapes of the parts of the honeycomb structure 1 that make up each current path are identical or symmetrical, the lengths of the current paths may be considered to be equal. Furthermore, the length of the current path being "equal" means that the length of each current path is within ±10%. The electrical resistance of each current path is a value measured at 25°C using the four-terminal method.

[0080] 8, when a current path in which a current flows in the first direction FD along the outer peripheral wall 100 and / or the partition wall 101, then in the second direction SD, and then again in the first direction FD is defined as one path, it is preferable that the number of paths for each of the first current path 5012, the second current path 5023, and the third current path 5034 is one or more. In a preferred embodiment of the present invention, the first electrode 501, the second electrode 502, the third electrode 503, and the fourth electrode 504 can be disposed on the first side surface 105 or the second side surface 106 of the honeycomb structure 1 so that the first current path 5012, the second current path 5023, and the third current path 5034 have even more paths. With regard to the embodiment shown in FIG. 8, by increasing the number of first slits 103a and second slits 103b while maintaining the positional relationship between the first electrode 501, the second electrode 502, the third electrode 503, and the fourth electrode 504, it is possible to increase the number of paths of the first current path 5012, the second current path 5023, and the third current path 5034.

[0081] Fig. 9 is a schematic diagram showing the structure of a three-phase honeycomb heater 60 according to another embodiment of the present invention. Fig. 9(A) is a cross-sectional view of the three-phase honeycomb heater 60 when observing a cross section perpendicular to the cell extension direction, and Fig. 9(B) is a side view of the three-phase honeycomb heater 60 in a direction parallel to the cell extension direction. Enlarged views of the partition walls and cells are omitted. Explanation of the configuration common to the embodiment of Fig. 8 is also omitted.

[0082] In the embodiment shown in FIG. 9 , the first current path 6012 between the first electrode 601 and the second electrode 602, the second current path 6023 between the second electrode 602 and the third electrode 603, and the third current path 6034 between the third electrode 603 and the fourth electrode 604 are the longest, the second current path 6023 is the next longest, and the third current path 6034 is the shortest. Counting the number of paths, the first current path 6012 has five paths, the second current path 6023 has three paths, and the third current path 6034 has one path. However, because these current paths form a delta connection, the advantages of the present invention can be obtained. Furthermore, by changing the material of the honeycomb structure 1 included in the first current path 6012, the second current path 6023, and the third current path 6034, the electrical resistances of these current paths can be made equal.

[0083] Figure 10 is a schematic diagram showing the structure of a three-phase honeycomb heater 70 according to yet another embodiment of the present invention. Figure 10(A) is a cross-sectional view of the three-phase honeycomb heater 70 when observing a cross section perpendicular to the cell extension direction, and Figure 10(B) is a side view of the three-phase honeycomb heater 70 in a direction parallel to the cell extension direction. Note that enlarged views of the partition walls and cells are omitted.

[0084] In the three-phase honeycomb heater 70 shown in Fig. 10, a first electrode 701 and a third electrode 703 are connected on a first side surface 105, and a second electrode 702 and a fourth electrode 704 are connected on a second side surface 106. Four first slits 103a and four second slits 103b are provided. As a result, a first current path 7012, a second current path 7023, and a third current path 7034 having equal lengths are formed.

[0085] Other configurations of the three-phase honeycomb heater 70 shown in FIG. 10 are similar to those of the three-phase honeycomb heater 50 shown in FIG. 8, so further detailed description will be omitted.

[0086] Fig. 11 is a schematic diagram showing the structure of a three-phase honeycomb heater 70 according to yet another embodiment of the present invention. Fig. 11(A) is a cross-sectional view of the three-phase honeycomb heater 80 when observing a cross section perpendicular to the extension direction of the cells 102, and Fig. 11(B) is a side view of the three-phase honeycomb heater 80 in a direction parallel to the extension direction of the cells 102.

[0087] In the three-phase honeycomb heater 80 shown in FIG. 11, the honeycomb structure 1 has a first side surface 105 and a second side surface 106 facing the first side surface 105 on the outer peripheral wall 100, and the slits 103 are formed as follows: first slits 103a extending along the first direction FD from the first side surface 105 and having a tip on the second side surface 106 side when directions perpendicular to each other in a cross section parallel to the extension direction of the cells 102 are defined as a first direction FD and a second direction SD; and a second slit 103b spaced apart from 103a in the second direction SD, extending along the first direction FD from the second side surface 106 as a base end and having a tip on the first side surface 105 side, the first slits 103a and the second slits 103b being arranged alternately in the second direction SD in a cross section parallel to the extension direction of the cell 102, thereby enabling current to flow in the first direction FD and the second direction SD along the outer wall 100 and / or the partition wall 101 in a repeated sequence.

[0088] That is, in the three-phase honeycomb heater 80 of the embodiment shown in Fig. 11, the direction in which the first slits 103a and the second slits 103b are arranged is different from the direction in which the first slits 103a and the second slits 103b are arranged in the three-phase honeycomb heater 50 of the embodiment shown in Fig. 8. However, even with this configuration of the first slits 103a and the second slits 103b, it is possible to define in the outer wall 100 and the partition wall 101 an electric current path having a first electric current path 8012, a second electric current path 8023, and a third electric current path 8034 for connecting the first electrode 801, the second electrode 802, the third electrode 803, and the fourth electrode 804 in a delta connection.

[0089] 11, when a current path in which a current flows in the first direction FD along the outer peripheral wall 100 and / or the partition wall 101, then in the second direction SD, and then again in the first direction FD is defined as one path, the number of paths for the first current path 8012, the second current path 8023, and the third current path 8034 is each one path. In a preferred embodiment of the present invention, the first electrode, the second electrode, the third electrode, and the fourth electrode can be disposed on the first side surface or the second side surface of the honeycomb structure 1 so that the first current path, the second current path, and the third current path have an even greater number of paths. With regard to the embodiment shown in FIG. 11, by increasing the number of first slits 103a and second slits 103b while maintaining the positional relationship between the first electrode 801, the second electrode 802, the third electrode 803, and the fourth electrode 804, it is possible to increase the number of paths of the first current path 8012, the second current path 8023, and the third current path 8034 when the current path is considered to be one path.

[0090] Other configurations of the three-phase honeycomb heater 70 shown in FIG. 11 are similar to those of the three-phase honeycomb heater 50 shown in FIG. 8, so further detailed description will be omitted.

[0091] Fig. 12 is a schematic diagram showing the structure of a three-phase honeycomb heater 70 according to yet another embodiment of the present invention. Fig. 12(A) is a cross-sectional view of a three-phase honeycomb heater 90 when observing a cross section perpendicular to the cell extension direction, and Fig. 12(B) is a side view of the three-phase honeycomb heater 90 in a direction parallel to the cell extension direction. Enlarged views of the partition walls and cells are omitted.

[0092] In the three-phase honeycomb heater 90 shown in Fig. 12, a first electrode 901 and a third electrode 903 are connected on a first side surface 105, and a second electrode 902 and a fourth electrode 904 are connected on a second side surface 106. Four first slits 103a and four second slits 103b are provided. As a result, a first current path 9012, a second current path 9023, and a third current path 9034 having equal lengths are formed.

[0093] Other configurations of the three-phase honeycomb heater 90 shown in FIG. 12 are similar to those of the three-phase honeycomb heater 50 shown in FIG. 8, and therefore further detailed description will be omitted.

[0094] Fig. 13 is a schematic diagram showing the structure of a three-phase honeycomb heater 21 according to yet another embodiment of the present invention. Fig. 13(A) is a cross-sectional view of the three-phase honeycomb heater 21 when observing a cross section perpendicular to the cell extension direction, and Fig. 13(B) is a side view of the three-phase honeycomb heater 21 in a direction parallel to the cell extension direction. Note that enlarged views of the partition walls and cells are omitted.

[0095] The embodiment shown in FIG. 13 differs from the embodiment shown in FIG. 8 in that the three-phase honeycomb heater 21 includes two honeycomb structures 11 and 12. Specifically, two honeycomb structures 11 and 12, each having a structure similar to that of the honeycomb structure 1 of the embodiment shown in FIG. 8, are joined via a conductive joint 107. A first electrode 211, a second electrode 212, a third electrode 213, and a fourth electrode 214 are connected to a first side surface 105 of the honeycomb structure 12. As a result, a first current path 2112, a second current path 2123, and a third current path 2134 are formed. Note that, since the thickness of the conductive joint 107 accounts for a very small proportion of the second current path 2123, the lengths of the first current path 2112, the second current path 2123, and the third current path 2134 can be considered to be substantially equal. Furthermore, since the effect of the electrical resistance of the conductive joint 107 is small, the electrical resistances of the first current path 2112, the second current path 2123, and the third current path 2134 can be considered to be substantially equal.

[0096] Various materials can be used for the conductive joints 107. For example, the same materials as those for the first electrode 211, the second electrode 212, the third electrode 213, and the fourth electrode 214, such as metals, conductive ceramics, or composites of metals and conductive ceramics (cermets), can be used for the conductive joints 107. Examples of metals include Cr, Fe, Co, Ni, Si, and Ti. The conductive joints 107 may be provided in at least a portion of the region where the honeycomb structures 11 and 12 face each other. The volume resistivity of the conductive joints 107 is preferably equal to or lower than the volume resistivity of the honeycomb structures 11 and 12. Furthermore, the conductive joints 107, the honeycomb structures 11 and 12, the first electrode 211, the second electrode 212, the third electrode 213, and the fourth electrode 214 are preferably made of the same material. This configuration can reduce the difference in thermal expansion coefficient among the conductive joint 107, the honeycomb structures 11 and 12, the first electrode 211, the second electrode 212, the third electrode 213, and the fourth electrode 214, thereby increasing the bonding strength therebetween. This can also contribute to improving productivity.

[0097] In a cross section perpendicular to the cell extension direction, the thickness of the conductive joint 107 is not particularly limited, but can be, for example, 500 μm to 5 mm. The thickness of the conductive joint 107 can correspond to the distance between the honeycomb structure 11 and the honeycomb structure 12. [Industrial Applicability]

[0098] The honeycomb structure and the three-phase honeycomb heater according to the embodiment of the present invention can be used, for example, as a catalyst carrier on which a catalyst is supported. [Explanation of symbols]

[0099] 1 Honeycomb structure 100 Peripheral wall 101 Bulkhead 102 cells 103 Slit 103a First slit 103b Second slit 104 Connection 105 First aspect 106 Second aspect 20 Three-phase honeycomb heater 201 1st electrode 202 2nd electrode 203 3rd electrode 30 Three-phase honeycomb heater 301 1st electrode 302 2nd electrode 303 3rd electrode 40 Three-phase honeycomb heater 401 1st electrode 402 2nd electrode 403 3rd electrode 501 1st electrode 502 2nd electrode 503 3rd electrode 504 4th electrode 5012 First current path 5023 Second energized path 5034 Third current path 60 Three-phase honeycomb heater 601 1st electrode 602 2nd electrode 603 3rd electrode 604 4th electrode 6012 First current path 6023 Second current path 6034 Third current path 70 Three-phase honeycomb heater 701 1st electrode 702 2nd electrode 703 3rd electrode 704 4th electrode 7012 First current path 7023 Second energized path 7034 Third current path 80 Three-phase honeycomb heater 801 1st electrode 802 2nd electrode 803 3rd electrode 804 4th electrode 8012 First current path 8023 Second current path 8034 Third current path 90 Three-phase honeycomb heater 901 1st electrode 902 2nd electrode 903 3rd electrode 904 4th electrode 9012 First current path 9023 Second energized path 9034 3rd current path 21 Three-phase honeycomb heater 11 Honeycomb structure 12 Honeycomb structure 107 Conductive joints 211 1st electrode 212 2nd electrode 213 3rd electrode 214 4th electrode 2112 First energized path 2123 Second energized path 2134 Third energized path

Claims

1. a honeycomb structure including an outer peripheral wall and partition walls disposed inside the outer peripheral wall to define a plurality of cells that form flow paths extending from one end face to the other end face; a first electrode connected to the outer peripheral wall and connectable to a first phase output terminal (R) of a three-phase AC power supply circuit; a second electrode connected on the outer peripheral wall and spaced apart from the first electrode, the second electrode being connectable to a second phase output terminal (S) of the three-phase AC power supply circuit; a third electrode on the outer peripheral wall, the third electrode being connected to the first electrode and the second electrode and spaced apart from each other, and connectable to a third-phase output terminal (T) of the three-phase AC power supply circuit; The honeycomb structure is a slit arranged in the outer peripheral wall and / or the partition wall so as to define a current path for connecting the first electrode, the second electrode, and the third electrode in a star-shaped connection; a connection portion connecting the first electrode, the second electrode, and the third electrode to one another; A three-phase honeycomb heater equipped with:

2. 2. The three-phase honeycomb heater according to claim 1, wherein the electrical resistances of three current paths from the connection portion to the outer peripheral wall to which the first electrode, the second electrode, and the third electrode are connected are equal.

3. 3. The three-phase honeycomb heater according to claim 2, wherein three current paths from the connection portion to the outer peripheral wall to which the first electrode, the second electrode, and the third electrode are connected have equal lengths.

4. The honeycomb structure has a first side surface and a second side surface opposite to the first side surface on the outer wall, the slits have a base end at the first side surface, extend toward the second side surface, and have a plurality of slits extending in a direction parallel to the extension direction of the cells, the connection portion is arranged on the second side surface side, and the first electrode, the second electrode, and the third electrode are arranged on the first side surface.

5. The honeycomb structure has a first side surface and a second side surface facing the first side surface on the outer wall, The three-phase honeycomb heater according to any one of claims 1 to 3, wherein when directions perpendicular to each other in a cross section perpendicular to the extension direction of the cells are defined as a first direction and a second direction, the slits extend in the first direction and the second direction and have a plurality of slits extending parallel to the extension direction of the cells, and the connection portion is arranged inside the honeycomb structure.

6. a honeycomb structure including an outer peripheral wall and partition walls disposed inside the outer peripheral wall to define a plurality of cells that form flow paths extending from one end face to the other end face; a first electrode connected to an outer peripheral wall of the honeycomb structure and connectable to a first phase output terminal (R) of a three-phase AC power supply circuit; a second electrode connected to an outer peripheral wall of the honeycomb structure apart from the first electrode and connectable to a second phase output terminal (S) of the three-phase AC power supply circuit; a third electrode connected to an outer peripheral wall of the honeycomb structure at a distance from the first electrode and the second electrode, and connectable to a third phase output terminal (T) of the three-phase AC power supply circuit; a fourth electrode connected to an outer peripheral wall of the honeycomb structure and spaced apart from the first electrode, the second electrode, and the third electrode, and connectable to a first phase output terminal (R) of the three-phase AC power supply circuit, The honeycomb structure is a three-phase honeycomb heater comprising slits arranged in the outer peripheral wall and the partition walls to define current paths having a first current path, a second current path, and a third current path for connecting the first electrode, the second electrode, the third electrode, and the fourth electrode in a delta connection.

7. 7. The three-phase honeycomb heater according to claim 6, wherein the current paths include the first current path between the first electrode and the second electrode, the second current path between the second electrode and the third electrode, and the third current path between the third electrode and the fourth electrode, and the first current path, the second current path, and the third current path have equal electrical resistances.

8. 8. The three-phase honeycomb heater according to claim 7, wherein the current paths include the first current path between the first electrode and the second electrode, the second current path between the second electrode and the third electrode, and the third current path between the third electrode and the fourth electrode, and the first current path, the second current path, and the third current path have equal lengths.

9. The honeycomb structure has a first side surface and a second side surface facing the first side surface on the outer wall, The slit is When directions orthogonal to each other in a cross section perpendicular to the extension direction of the cell are defined as a first direction and a second direction, a first slit extends along the first direction from the first side surface as a base end and has a tip end on the second side surface side; a second slit spaced apart from the first slit in the second direction, the second slit extending along the first direction from the second side surface as a base end and having a tip end on the first side surface side; Equipped with The three-phase honeycomb heater according to any one of claims 6 to 8, wherein the first slits and the second slits are alternately arranged in the second direction in a cross section perpendicular to the extension direction of the cells, thereby allowing current to flow in the first direction and the second direction along the outer peripheral wall and / or the partition walls in a repeated sequence.

10. The honeycomb structure has a first side surface and a second side surface facing the first side surface on the outer wall, The slit is When directions orthogonal to each other in a cross section parallel to the extension direction of the cell are defined as a first direction and a second direction, a first slit extends along the first direction from the first side surface as a base end and has a tip end on the second side surface side; a second slit spaced apart from the first slit in the second direction in a cross section parallel to the extending direction of the cell, the second slit extending along the first direction with the second side surface as a base end and having a tip end on the first side surface side; Equipped with The three-phase honeycomb heater according to any one of claims 6 to 8, wherein the first slits and the second slits are alternately arranged in the second direction in a cross section parallel to the extension direction of the cells, thereby allowing current to flow in the first direction and the second direction along the outer peripheral wall and / or the partition walls in a repeated sequence.

11. 10. The three-phase honeycomb heater according to claim 9, wherein the first electrode, the second electrode, the third electrode, and the fourth electrode are connected on the first side surface.

12. The three-phase honeycomb heater according to claim 10, wherein the first electrode, the second electrode, the third electrode, and the fourth electrode are connected on the first side surface.

13. 10. The three-phase honeycomb heater according to claim 9, wherein the first electrode, the second electrode, the third electrode, and the fourth electrode are arranged on the first side surface or the second side surface so that, in a cross section perpendicular to the extension direction of the cells, one current path is defined as a current path in which a current flows in the first direction along the outer peripheral wall and / or the partition wall, then in the second direction, and then in the first direction, and one or more current paths are provided for each of the first current path, the second current path, and the third current path.

14. 11. The three-phase honeycomb heater according to claim 10, wherein the first electrode, the second electrode, the third electrode, and the fourth electrode are arranged separately on the first side surface or the second side surface so that, in a cross section parallel to the extension direction of the cells, when a current path in which a current flows in the first direction along the outer peripheral wall and / or the partition wall, then flows in the second direction, and then flows in the first direction is defined as one path, the first current path, the second current path, and the third current path each have one or more paths.

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