Honeycomb structure, method for manufacturing same, and arrangement structure of honeycomb structures

Abstract

To provide a honeycomb structure arranged inside a radiant tube, which has a simple structure but has a high working effect as a heat transfer promotion body or a heat storage body.SOLUTION: In this invention, the configuration of a ceramic honeycomb structure 1 with multiple cells 15 demarcated by bulkheads 11 extending in a single direction has a through hole 21 penetrating parallel to the cell axis. The through-hole 21 has an opening area in the transverse section perpendicular to the cell axis that is larger than the opening area of the cell 15, and the opening center P is located at the outer edge 10p where the distance from the center point C in the transverse section is more than half of the distance R between the center point C and the outer circumference, and in the inner space of the through-hole 21, the cross section of the bulkhead 11 is exposed and the cell 15 is open.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a honeycomb structure disposed inside a radiant tube as a heat transfer promoter or a heat storage body, a method for manufacturing the same, and an arrangement structure of the honeycomb structure.

Background Art

[0002] A radiant tube heater is a device that circulates a gas heated by a burner or the like inside a tube (radiant tube) made of metal or ceramic to heat the tube, and indirectly heats an object to be heated by radiant heat from the heated tube.

[0003] However, when the heated gas (hereinafter referred to as "heating gas") flows through the tube, since the frictional resistance acts near the inner wall surface of the tube and it is difficult for the gas to flow, the heating gas easily flows near the center of the tube, and it is difficult for heat to be transferred to the tube. In addition, the temperature of the heating gas flowing near the inner wall surface of the tube decreases due to heat exchange with the inner wall surface. For this reason, there has been a problem that the tube cannot be sufficiently heated as the distance from a heating source such as a burner increases.

[0004] Therefore, conventionally, a heat transfer promoter has been disposed at a position away from the heating source inside the radiant tube. The heat of the heating gas flowing through the tube is recovered by the heat transfer promoter, and heat is transferred from the heat transfer promoter to the tube, so that heat transfer from the heating gas to the radiant tube can be promoted.

[0005] The present applicant has proposed to dispose a honeycomb structure including a plurality of cells partitioned by partition walls extending in a single direction and arranged in a row as such a heat transfer promoter (see Patent Documents 1 and 2). Since the honeycomb structure has a large surface area and a large area in contact with the heating gas, it has the advantages of efficiently recovering the heat of the heating gas and having a large area for radiating heat toward the inner wall surface of the tube.

[0006] In addition, the honeycomb structures of Patent Documents 1 and 2 have a structure that is more likely to radiate heat toward the inner wall surface of the tube. Specifically, in the honeycomb structure of Patent Document 1, at least one of both end faces is inclined with respect to a plane orthogonal to the axial direction of the tube, so that the heat radiated from the end face can be efficiently transmitted to the tube. Further, the honeycomb structure of Patent Document 2 is a honeycomb structure in which a plurality of segments having a honeycomb structure are joined, and the segments are joined such that the extending directions of the cell axes of two or more segments are different. With such a configuration, since the gas that has passed through the honeycomb structure travels in different directions within the tube, turbulence can be generated in the gas flow, and the gas can be circulated even in the vicinity of the inner wall surface of the tube where the gas is difficult to flow due to frictional resistance, and the heat of the heated gas can be efficiently transmitted to the radiant tube.

[0007] However, while the honeycomb structures of Patent Documents 1 and 2 can efficiently transmit the heat of the heated gas to the tube, there was room for improvement in that the structure was complex and thus time-consuming to manufacture.

[0008] On the other hand, there are regenerative radiant tube heaters. This is a heater in which the gas flow direction is switched at predetermined time intervals so that the gas is alternately circulated through the same heat exchange section when the gas heated to a high temperature by the combustion of the burner is discharged and when new gas is supplied for the combustion of the burner. A heat storage body is disposed inside the heat exchange section, and the heat of the discharged heated gas is recovered by the heat storage body, and this heat is used to preheat the new gas supplied for the combustion of the burner. Such regenerative radiant tube heaters include a type that uses a pair of burners combined with the heat exchange section and a type that switches the gas flow direction with a single burner.

[0009] As a heat storage body of a regenerative radiant tube heater, solid balls are used, while a honeycomb structure may be used (see Patent Document 3). However, as described above, since frictional resistance occurs near the inner wall surface of the tube and it is difficult for gas to flow, the gas easily flows near the center of the tube, and the heated gas that has flowed through the vicinity of the center directly advances as it is and easily passes only through the vicinity of the center of the honeycomb structure. As a result, only the vicinity of the center of the honeycomb structure is partially used as a heat storage body, and there is a problem that the advantage of the honeycomb structure having a very large specific surface area cannot be fully utilized. Therefore, a honeycomb structure with high acting effects as a heat transfer promoter or a heat storage body has been desired without complicating the structure.

Prior Art Documents

Patent Documents

[0010]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0011] Therefore, in view of the above situation, the present invention provides a honeycomb structure disposed inside a radiant tube, which has a simple configuration and high acting effects as a heat transfer promoter or a heat storage body, a method for manufacturing the same, and an arrangement structure of the honeycomb structure.

Means for Solving the Problems

[0012] To solve the above problems, the honeycomb structure according to the present invention is "a ceramic honeycomb structure including a plurality of cells partitioned by partition walls extending in a single direction and arranged in a row It is a honeycomb structure for arranging as a heat transfer promoter or a heat storage body inside the tube of a radiant tube heater and It has a through-hole penetrating the honeycomb structure parallel to the cell axis which is the extending direction of the cells, and the through-hole has an opening area in a cross-section perpendicular to the cell axis, which is A plurality of larger than the opening area of the cells, Are circular holes and the center of the opening is located at an outer edge portion where the distance from the center point of the cross-section is one-half or more of the distance between the center point and the outer periphery, and the cross-section of the partition wall is exposed in the internal space of the through-hole, and the cells are open in the internal space.

[0013] The honeycomb structure of this configuration has a through-hole penetrating parallel to the cell axis. Since the opening area of the through-hole in the cross-section is larger than the opening area of the cells, when the honeycomb structure is arranged in a tube through which heated gas flows, the gas preferentially flows through the through-hole while flowing through the cells. And the center of the opening of the through-hole is located at the outer edge portion in the cross-section. Therefore, the heated gas preferentially flows through the outer edge portion in the honeycomb structure.

[0014] Therefore, when the honeycomb structure is arranged as a heat transfer promoter inside the radiant tube, the heated gas easily flows through the through-holes at the outer edge portion, and the heat of the heated gas is well recovered at the outer edge portion of the honeycomb structure. Since the outer edge portion close to the inner wall surface of the tube in the honeycomb structure is well heated, the heat recovered from the heated gas can be well transferred to the tube. On the other hand, when the honeycomb structure is arranged as a heat storage body in the regenerative radiant tube, the heated gas also easily flows through the through-holes at the outer edge portion, and the heat of the heated gas is well recovered at the outer edge portion of the honeycomb structure. As a result, in the conventional honeycomb structure, a large amount of heat can be stored even at the outer edge portion where the function as a heat storage body could not be fully exerted because the gas flow was difficult, and the function as a heat storage body can be exerted overall in the honeycomb structure.

[0015] In addition, in the honeycomb structure of this configuration, the cross-section of the partition wall is exposed in the internal space of the through-hole, and the cells are open. In such a configuration, the inner surface of the cell and the cross-section of the partition wall constitute the inner peripheral surface of the through-hole, and the surface area is extremely large. Therefore, the contact area between the heating gas flowing through the through-hole and the honeycomb structure becomes extremely large, and the heat of the heating gas can be sufficiently recovered.

[0016] The honeycomb structure of the above configuration can be manufactured by the following manufacturing method. That is, "Through the process of extrusion molding a ceramic raw material, a molded body having a honeycomb structure provided with a plurality of cells partitioned by partition walls extending in a single direction and arranged in a row is formed, Before or after firing the molded body, a through-hole penetrating parallel to the cell axis, which is the direction in which the cells extend, is formed by punching, The through-hole With , The opening area in the cross-section, which is a cross-section orthogonal to the cell axis There are a plurality of is larger than the opening area of the cell Circular holes and is formed such that the opening center is located at an outer edge portion where the distance from the center point of the cross-section is one-half or more of the distance between the center point and the outer periphery. " This is the manufacturing method. By this Manufacture a honeycomb structure for arranging as a heat transfer promoter or a heat storage body inside the tube of a radiant tube heater

[0017] When extruding a honeycomb structure made of ceramics, a mold corresponding to the cross-sectional shape is manufactured, and a kneaded material made of a ceramic raw material is extruded from this mold. Therefore, when attempting to manufacture a honeycomb structure having through holes penetrating in a direction parallel to the cell axis, it may be conceivable to provide a hole-shaped portion for forming the through holes in the extrusion mold. However, in that case, the inner peripheral surface of the through holes formed by extrusion molding is similar to the inner peripheral surface of a cylinder and the surface area is not large. On the other hand, in this manufacturing method, after forming a molded body having a honeycomb structure by extrusion molding, before or after firing the molded body, through holes are formed by punching. Therefore, the partition walls partitioning the cells are partially cut away, the cross section of the partition wall is exposed in the internal space of the through holes, and the cells are open in the internal space, and a honeycomb structure having a very large contact area with the heating gas flowing through the through holes can be manufactured.

[0018] Also, since through holes are formed by punching a molded body or a fired body having a honeycomb structure, a honeycomb structure having a simple configuration and a high effect as a heat transfer promoter or a heat storage body can be easily manufactured.

[0019] The honeycomb structure according to the present invention, instead of the above configuration, "is a ceramic honeycomb structure including a plurality of cells partitioned by partition walls arranged in a row extending in a single direction, It is a honeycomb structure for arranging as a heat transfer promoter or a heat storage body inside the tube of a radiant tube heater wherein, it has a through groove penetrating the honeycomb structure in parallel with the cell axis which is the direction in which the cells extend, the through groove, has an opening area in a cross-sectional plane which is a cross-section orthogonal to the cell axis A plurality of larger than the opening area of the cells, Are arcuate grooves and, opens at the outer periphery of the cross-sectional plane, and the cross section of the partition wall is exposed in the inner space of the through groove, and the cells are open in the inner space" can also be used.

[0020] The honeycomb structure of this configuration has through-grooves penetrating parallel to the cell axis. Since the opening area of the through-grooves in the cross-section is larger than the opening area of the cells, when the honeycomb structure is disposed in a tube through which heated gas flows, the gas preferentially flows through the through-grooves while flowing through the cells. And since the through-grooves open at the outer periphery in the cross-section, the heated gas preferentially flows through the outer peripheral side of the honeycomb structure.

[0021] Therefore, when the honeycomb structure is disposed as a heat transfer promoter inside the radiant tube, the heated gas easily flows through the through-grooves on the outer peripheral side, and the heat of the heated gas is well recovered near the outer periphery of the honeycomb structure. Since the outer periphery near the inner wall surface of the tube in the honeycomb structure is well heated, the heat recovered from the heated gas can be well transferred to the tube.

[0022] On the other hand, even when the honeycomb structure is disposed as a heat storage body inside the regenerative radiant tube, the heated gas easily flows through the through-grooves on the outer peripheral side, and the heat of the heated gas is well recovered near the outer periphery of the honeycomb structure. As a result, in the conventional honeycomb structure, a large amount of heat can be stored even in the outer periphery where the action as a heat storage body could not be fully exerted because the gas was difficult to flow, and the action as a heat storage body can be exerted on the honeycomb structure as a whole.

[0023] In addition, in the honeycomb structure of this configuration, the cross-section of the partition wall is exposed in the inner space of the through-groove, and the cells are open. In such a configuration, the inner surface of the cell and the cross-section of the partition wall constitute the inner surface of the through-groove, and the surface area is extremely large. Therefore, the contact area between the heated gas flowing through the through-groove and the honeycomb structure becomes extremely large, and the heat of the heated gas can be sufficiently recovered.

[0024] Furthermore, when the honeycomb structure is used as a heat transfer promoter, the outer peripheral surface is a surface that radiates heat toward the inner wall surface of the tube. However, since the surface area of the inner surface of the through-groove that opens at the outer periphery is extremely large, the area that radiates heat toward the inner wall surface of the tube is also extremely large, and there is an advantage that a large amount of heat is transferred to the tube.

[0025] The honeycomb structure having the above-mentioned through grooves can be manufactured by the following manufacturing method. "By subjecting a ceramic raw material to a process of extrusion molding, a honeycomb-structured molded body is formed having a plurality of cells separated by partition walls arranged in a row extending in a single direction, Before or after firing the molded body, a through groove is formed by hollowing out the molded body so as to penetrate the molded body in a direction parallel to a cell axis, which is the extension direction of the cells; The through groove With , Opening area in a cross section perpendicular to the cell axis There are a plurality of The opening area of the cell is larger than the opening area of the cell. Arcuate grooves At the same time, The cross section is formed so as to have an opening at the outer periphery. By this Manufacture a honeycomb structure for arranging as a heat transfer promoter or a heat storage body inside the tube of a radiant tube heater " This is the manufacturing method.

[0026] In this manufacturing method, instead of providing a cutout portion for forming the through groove in the extrusion mold, a molded body having a honeycomb structure is formed by extrusion molding, and then the through groove is formed by hollowing out the molded body before or after firing. Therefore, the partition walls dividing the cells are partially cut away, and the cross section of the partition wall is exposed in the inner space of the through groove, and the cells are opened in the inner space, so that a honeycomb structure having an extremely large contact area with the heated gas flowing through the through groove can be manufactured.

[0027] Furthermore, since the through grooves are formed by hollowing out a molded body or fired body having a honeycomb structure, a honeycomb structure that has a simple configuration but has a high function as a heat transfer promoter or heat storage body can be easily manufactured.

[0028] In addition to the above configuration, the honeycomb structure having the through holes or through grooves has the following features: The honeycomb structure can be configured as "a plurality of segments each having a honeycomb structure including a plurality of cells partitioned by partition walls extending in a single direction and arranged in a row are joined together."

[0029] In this configuration, since the honeycomb structure is formed by joining a plurality of segments, the degree of freedom in the size of the honeycomb structure is high.

[0030] The honeycomb structure having such a configuration is manufactured by the following manufacturing method. That is, "The molded body is a molded body of a segment having a honeycomb structure including a plurality of cells partitioned by partition walls extending in a single direction and arranged in a row, and a plurality of the segments are joined before or after firing the molded body." This is the manufacturing method.

[0031] The order of "formation of through holes or through grooves" performed before or after firing the molded body and "joining of segments" performed before or after firing the molded body does not matter. That is, after firing the molded body of the segment, formation of through holes or through grooves may be performed and then joining may be carried out, or joining of segments may be carried out and then formation of through holes or through grooves may be performed. Alternatively, after forming through holes or through grooves in the molded body of the segment, it may be fired and then joined, or joined and then fired. Or, after joining the molded body of the segment, formation of through holes or through grooves may be performed after firing, or formation of through holes or through grooves may be performed and then fired.

[0032] Next, the arrangement structure of the honeycomb structure according to the present invention is "the honeycomb structure described above is arranged as a heat transfer promoter or a heat storage body inside the tube of a radiant tube heater."

[0033] Since the honeycomb structure has through holes in its outer edge portion, through grooves on its outer peripheral side, or both, when it is arranged as a heat transfer promoter inside the radiant tube, as described above, it is easy to transfer the heat of the heating gas to the tube. Further, when it is arranged as a heat storage body inside the radiant tube, as described above, the function as a heat storage body can be exerted on the honeycomb structure as a whole.

Advantages of the Invention

[0034] As described above, according to the present invention, there can be provided a honeycomb structure arranged inside a radiant tube, which has a simple structure and high effects as a heat transfer promoter or as a heat storage body, a method for manufacturing the same, and an arrangement structure of the honeycomb structure.

Brief Description of the Drawings

[0035]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0036] Hereinafter, a honeycomb structure which is a specific embodiment of the present invention and a method for manufacturing the same will be described with reference to the drawings. The honeycomb structure of the present embodiment is for forming an arrangement structure in which a honeycomb structure is arranged as a heat transfer promoter or a heat storage body in a tube of a radiant tube heater.

[0037] The honeycomb structure of the present embodiment is manufactured by a manufacturing method including a "forming" step, at least one of a "through-hole forming" step and a "through-groove forming" step, and a "firing" step. Further, as an optional step, a manufacturing method including a "joining" step can be adopted.

[0038] In the "forming" step, a kneaded material obtained by mixing a ceramic raw material with water or a binder is extruded from a mold to form a formed body having a honeycomb structure. The outer shape of the formed body can be cylindrical, elliptical columnar, or prismatic. The cross-sectional shape of the cells can be polygonal such as square, triangular, or hexagonal.

[0039] The material of the ceramics is not particularly limited, and examples thereof include silicon carbide, alumina, cordierite, and mullite. Since silicon carbide has a high thermal conductivity, it is suitable for use as a heat transfer promoter. In addition, since silicon carbide has a small thermal expansion coefficient in addition to a high thermal conductivity, it is excellent in thermal shock resistance and is suitable for use as a heat storage body that repeats heating and cooling.

[0040] In the "firing" step, heating is performed at a temperature lower than the melting point for a predetermined time to sinter the ceramic particles. Oxide ceramics such as alumina, cordierite, and mullite are fired in an oxidizing atmosphere, and non-oxide ceramics such as silicon carbide are fired in a non-oxidizing atmosphere such as a nitrogen gas atmosphere, an inert gas atmosphere, or a mixed atmosphere thereof.

[0041] The "joining" process is a process of joining a plurality of segments with a joining material, and the details are the same as those of the "through-hole forming" process and the "through-groove forming" process described later, and it is carried out before or after the firing process after the forming process. Regardless of the order of the "joining" process, the "through-hole forming" process, and the "through-groove forming" process, each process can be carried out in the following order. (1) "Forming" → "Firing" → "Through-hole forming and through-groove forming" → "Joining" (2) "Forming" → "Firing" → "Joining" → "Through-hole forming and through-groove forming" (3) "Forming" → "Through-hole forming and through-groove forming" → "Firing" → "Joining" (4) "Forming" → "Through-hole forming and through-groove forming" → "Joining" → "Firing" (5) "Forming" → "Joining" → "Firing" → "Through-hole forming and through-groove forming" (6) "Forming" → "Joining" → "Through-hole forming and through-groove forming" → "Firing"

[0042] (1) to (3) In the process order, since the joining process is carried out after the firing process, it is suitable for the case of exerting an action of relaxing the thermal stress on the layer of the joining material. As the joining material in such a case, a joining material obtained by mixing ceramic powder, inorganic fiber, and a binder (an inorganic binder such as colloidal silica, and / or an organic binder such as carboxymethyl cellulose) can be used.

[0043] On the other hand, in the process order of (4) to (6), since the firing process is carried out after the joining process, a joining material that can be fired under the same conditions as the honeycomb-structured formed body is used. For example, like the technology of Patent No. 5180942 proposed by the applicant of the present application, a joining material that becomes a ceramic sintered body by firing and is integrated with the segment having a honeycomb structure by sintering can be used.

[0044] The "through-hole forming" process and the "through-groove forming" process are carried out after the forming process and before or after the firing process, and are processes of punching out a formed body or a sintered body having a honeycomb structure so as to penetrate parallel to the cell axis. By punching out, the partition walls that partition the cells are partially removed. At this time, when punching out so that the cutting of the partition wall does not reach the outer peripheral wall, a through-hole is formed. On the other hand, when punching out so that the cutting of the partition wall reaches the outer peripheral wall, a through-groove that opens on the outer periphery is formed.

[0045] For example, like the honeycomb structure body 1 shown in Fig. 1(a), when a formed body or a sintered body having a honeycomb structure including a plurality of cells 15 partitioned by partition walls 11 arranged in a single direction and extending in a row is punched out so that the cutting of the partition walls 11 does not reach the outer peripheral wall 13, through-holes 21 are formed. At this time, as shown in Figs. 1(a) and (b), the through-holes 21 are formed such that the opening center P of the through-holes 21 is located at the outer edge portion 10p in the cross section (a section orthogonal to the cell axis). The outer edge portion 10p is a range in which the distance from the center point C is one-half or more of the distance R between the center point C and the outer periphery in the cross section (the hatched portion in Fig. 1(b)). Here, in the cross section, the line at a distance of R / 2 from the center point C is indicated by L.

[0046] Also, the size of the through-hole 21 is set such that the opening area of one through-hole 21 in the cross section is larger than the opening area of one cell 15. Here, the case where four through-holes 21 are formed at equal angular intervals with respect to the central axis in a columnar formed body or sintered body is illustrated.

[0047] In the internal space of the through-hole 21 formed by punching out, as shown in Fig. 1(c), the cross section of the partition wall 11 is exposed and the cell 15 is open.

[0048] When the honeycomb structure 1 having the above configuration is arranged as a heat transfer promoter inside the radiant tube, the heating gas easily flows through the through holes 21 in the outer edge portion 10p, and the heat of the heating gas is well recovered at the outer edge portion 10p of the honeycomb structure 1. In the honeycomb structure 1, since the outer edge portion 10p close to the inner wall surface of the tube is well heated, the heat recovered from the heating gas can be well transmitted to the tube.

[0049] On the other hand, even when the honeycomb structure 1 is arranged as a heat storage body inside the radiant tube, the heating gas easily flows through the through holes 21 in the outer edge portion 10p, and the heat of the heating gas is well recovered at the outer edge portion 10p of the honeycomb structure 1. As a result, in the conventional honeycomb structure, a large amount of heat can be stored even in the outer edge portion 10p where the function as a heat storage body could not be sufficiently exerted because the gas did not easily flow, and the function as a heat storage body can be exerted as a whole in the honeycomb structure 1.

[0050] Further, in the honeycomb structure 1, since the cross section of the partition wall 11 is exposed in the internal space of the through hole 21 and the cells 15 are open, the surface area is extremely large. Therefore, the contact area between the heating gas flowing through the through hole 21 and the honeycomb structure 1 becomes extremely large, and the heat of the heating gas can be sufficiently recovered.

[0051] In the honeycomb structure 1, the opening center P of the through hole 21 is located at the outer edge portion 10p, but the inside of the through hole 21 slightly extends over the line L. That is, it is an example in which a part of the through hole 21 is inside the outer edge portion 10p. On the other hand, as shown in FIGS. 2(a) and (b), the honeycomb structure 1b can be formed in which the entire through hole 21 is located at the outer edge portion 10p. Here, the case where eight through holes 21 are formed at equal angular intervals with respect to the central axis in a columnar molded body or fired body is exemplified. Even with such a configuration, the same operational effects as those of the honeycomb structure 1 are exhibited.

[0052] The number of through-holes 21 per honeycomb structure is not limited to the number exemplified for the honeycomb structures 1 and 1b. Further, although the honeycomb structures 1 and 1b are integral, a honeycomb structure manufactured through the bonding process described above as an optional step can be configured to have the through-holes 21. As an example, FIG. 3 shows a honeycomb structure 1c having a columnar outer shape similar to that of the honeycomb structure 1b, with eight through-holes 21 formed at equal angular intervals with respect to the central axis.

[0053] The honeycomb structure 1c is formed by joining a plurality of prismatic segments 30 having a honeycomb structure with a bonding material 33 and then processing the outer shape into a columnar shape. Even with such a configuration, the honeycomb structure 1c exhibits the same effects as the honeycomb structures 1 and 1b. In addition, since it is a joined body of a plurality of segments 30, there is an advantage of high degree of freedom in size.

[0054] In the above, the honeycomb structures 1, 1b, and 1c having the through-holes 21 were shown. Next, a honeycomb structure having a through-groove is shown. The honeycomb structure having a through-groove may be integral or a joined body formed by joining segments. As an example, FIGS. 4(a) and (b) show a honeycomb structure 1d which is a joined body of a plurality of segments 30 and has a through-groove 22. When a honeycomb structure formed body or fired body having a plurality of cells 15 partitioned by partition walls 11 arranged in a single direction and extending in a row is hollowed out so that the excision of the partition walls reaches the outer peripheral wall 13, a through-groove 22 opening at the outer periphery is formed. The size of the through-groove 22 is set such that the opening area of one through-groove 22 in the cross-section is larger than the opening area of one cell 15.

[0055] In the inner space of the through-groove 22 formed by hollowing out, as shown in FIG. 4(b), the cross-section of the partition wall 11 is exposed and the cells 15 are open. Here, although a case is exemplified in which a plurality of prismatic segments 30 having a honeycomb structure are joined with a bonding material 33 and then the outer shape is processed into a columnar shape, and eight through-grooves 22 are formed at equal angular intervals with respect to the central axis, the number thereof is not particularly limited.

[0056] The honeycomb structure 1d with such a configuration has a through groove 22 penetrating parallel to the cell axis, and since the opening area of the through groove 22 in the cross section is larger than the opening area of the cell 15, when the honeycomb structure is disposed in a tube through which a heating gas flows, the gas preferentially flows through the through groove 22 while flowing through the cell. And since the through groove 22 opens at the outer periphery in the cross section, the heating gas preferentially flows through the outer peripheral side in the honeycomb structure 1d.

[0057] Therefore, when the honeycomb structure 1d is disposed as a heat transfer accelerator inside the radiant tube, the heating gas easily flows through the through groove 22 on the outer peripheral side, and the heat of the heating gas is well recovered near the outer periphery of the honeycomb structure 1d. Since the outer periphery near the inner wall surface of the tube in the honeycomb structure 1d is well heated, the heat recovered from the heating gas can be well transmitted to the tube.

[0058] On the other hand, when the honeycomb structure 1d is disposed as a heat storage body inside the regenerative radiant tube, the heating gas easily flows through the through groove 22 on the outer peripheral side, and the heat of the heating gas is well recovered near the outer periphery of the honeycomb structure 1d. As a result, in the conventional honeycomb structure, much heat can be stored even in the outer periphery where the action as a heat storage body could not be sufficiently exerted because the gas hardly flowed, and the action as a heat storage body can be exerted on the honeycomb structure 1d as a whole.

[0059] In addition, in the honeycomb structure 1d, the cross section of the partition wall 11 is exposed in the inner space of the through groove 22, and since the cell 15 is open, the surface area is extremely large. Therefore, the contact area between the heating gas flowing through the through groove 22 and the honeycomb structure 1d becomes extremely large, and the heat of the heating gas can be sufficiently recovered.

[0060] Furthermore, when the honeycomb structure 1d is used as a heat transfer promoter, the outer peripheral surface is a surface that radiates heat toward the inner wall surface of the tube. However, since the surface area of the inner surface of the through groove 22 that opens on the outer periphery is extremely large, the area that radiates heat toward the inner wall surface of the tube is also extremely large, and there is an advantage that a large amount of heat is transferred to the tube.

[0061] As described above, the preferred embodiments of the present invention have been described. However, the present invention is not limited to the above-described embodiments, and various improvements and design changes can be made without departing from the gist of the present invention as shown below.

[0062] For example, it can be a honeycomb structure having both through holes and through grooves. As a result, it becomes a honeycomb structure having both the action of the honeycomb structure having the through hole 21 exemplified using the honeycomb structures 1, 1b, and 1c and the action of the honeycomb structure having the through groove 22 exemplified using the honeycomb structure 1d.

[0063] Also, like the honeycomb structures 1e and 1f illustrated in FIGS. 5(a) and 5(b), it can be configured to have a through hole 25 that is not located at the outer edge portion. Here, the case where the opening center of the through hole 25 coincides with the center point in the cross section is shown. Such a honeycomb structure having the through hole 25 is suitable for use as a heat storage body of a regenerative radiant tube heater. In a regenerative radiant tube heater, since a heat storage body is disposed at the position where the burner is inserted, the inner cylinder into which the burner is inserted can be inserted into the central through hole 25.

[0064] Note that the honeycomb structure 1e is an example having a through groove 22 that opens on the outer periphery in addition to the through hole 25, and the honeycomb structure 1f has a through hole 21 whose opening center is located at the outer edge portion in addition to the through hole 25, and is an example having through holes of different sizes as the through hole 21. Although the case where a plurality of segments 30 are joined by a joining material 33 is illustrated for both, they may be integrally formed.

[0065] Further, a coating may be applied to the outer surface of the honeycomb structure including at least one of the through holes 21 and the through grooves 22. Examples of the coating agent include those for the purpose of increasing the emissivity, those for the purpose of increasing the strength, and those for the purpose of suppressing oxidation when the honeycomb structure is made of non-oxide ceramics. Such coating can be performed by applying or spraying the coating agent onto the outer surface of the honeycomb structure. Alternatively, it can be performed by impregnating the honeycomb structure with the coating agent.

Explanation of Reference Numerals

[0066] 1, 1b, 1c, 1d, 1e, 1f Honeycomb structure 10p Outer edge portion 11 Partition wall 15 Cell 21 Through hole 22 Through groove 30 Segment 33 Bonding material C Center point (center point in the cross section) P Opening center (opening center of the through hole)

Claims

1. A honeycomb structure made of ceramics, comprising a plurality of cells partitioned by partition walls arranged in a single direction and extending in a row, which is a honeycomb structure for being arranged as a heat transfer promoter or a heat storage body inside a tube of a radiant tube heater, having a through-hole penetrating the honeycomb structure in parallel with the cell axis which is the extending direction of the cells, the through-hole being a circular hole having an opening area in a cross-section perpendicular to the cell axis that is larger than the opening areas of the plurality of cells, and having an opening center located at an outer edge portion where the distance from the center point of the cross-section is equal to or more than one half of the distance between the center point and the outer periphery, wherein the cross-section of the partition wall is exposed in the internal space of the through-hole and the cells are open in the internal space characterizing the honeycomb structure.

2. A honeycomb structure made of ceramics, comprising a plurality of cells partitioned by partition walls arranged in a single direction and extending in a row, which is a honeycomb structure for being arranged as a heat transfer promoter or a heat storage body inside a tube of a radiant tube heater, having a through-groove penetrating the honeycomb structure in parallel with the cell axis which is the extending direction of the cells, the through-groove being an arc-shaped groove having an opening area in a cross-section perpendicular to the cell axis that is larger than the opening areas of the plurality of cells, and opening at the outer periphery of the cross-section, wherein the cross-section of the partition wall is exposed in the inner space of the through-groove and the cells are open in the inner space characterizing the honeycomb structure.

3. The honeycomb structure is formed by joining a plurality of segments each having a honeycomb structure comprising a plurality of cells partitioned by partition walls arranged in a single direction and extending in a row characterizing the honeycomb structure according to Claim 1 or Claim 2.

4. Through a process of extrusion molding a ceramic raw material, a molded body having a honeycomb structure comprising a plurality of cells partitioned by partition walls arranged in a single direction and extending in a row is formed, before or after firing the molded body, a through-hole penetrating in parallel with the cell axis which is the extending direction of the cells is formed by punching, the through-hole being a circular hole having an opening area in a cross-section perpendicular to the cell axis that is larger than the opening areas of the plurality of cells, and By forming the opening center to be located at an outer edge portion where the distance from the center point of the cross-section is equal to or greater than half of the distance between the center point and the outer periphery, manufacturing a honeycomb structure for placement as a heat transfer promoter or a heat storage body within a tube of a radiant tube heater A method for manufacturing a honeycomb structure, characterized by the above.

5. Through a process of extrusion molding a ceramic raw material, a molded body having a honeycomb structure provided with a plurality of cells partitioned by partition walls extending in a single direction and arranged in a row is formed, before or after firing the molded body, a through groove penetrating parallel to the cell axis, which is the direction in which the cells extend, is formed by punching, The through groove is formed as an arcuate groove having an opening area in a cross-section perpendicular to the cell axis that is larger than the opening areas of the plurality of cells, and formed to open at the outer periphery of the cross-section, manufacturing a honeycomb structure for placement as a heat transfer promoter or a heat storage body within a tube of a radiant tube heater A method for manufacturing a honeycomb structure, characterized by the above.

6. The molded body is a segmented molded body having a honeycomb structure provided with a plurality of cells partitioned by partition walls extending in a single direction and arranged in a row, before or after firing the molded body, a plurality of the segments are joined A method for manufacturing a honeycomb structure according to claim 4 or claim 5, characterized by the above.

7. The honeycomb structure according to any one of claims 1 to 3 is arranged as a heat transfer promoter or a heat storage body within a tube of a radiant tube heater An arrangement structure of a honeycomb structure, characterized by the above.

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