JP6993954B2 - Manufacturing method of heat exchanger and heat exchanger - Google Patents

Description

The present invention relates to a method for manufacturing a heat exchanger and a heat exchanger.

As a heat exchanger that recovers heat from high-temperature exhaust gas and wastewater, a honeycomb structure having a plurality of cells partitioned by a single axially extending partition wall has been proposed. (For example, see Patent Document 1). In the heat exchanger described in Patent Document 1, a slit is formed by removing the partition wall after manufacturing the honeycomb structure.

Japanese Unexamined Patent Publication No. 2016-6373

However, in the heat exchanger described in Patent Document 1, there is a problem that the efficiency of heat exchange is lowered because pressure loss due to the internal structure occurs. Further, if the number of cells is increased in order to increase the heat transfer area, the pressure loss becomes larger, and the efficiency of heat exchange becomes lower due to the difference in the flow rate of each cell.

Therefore, the present invention has been made focusing on the above-mentioned problems, and an object of the present invention is to provide a method for manufacturing a heat exchanger and a heat exchanger capable of increasing the efficiency of heat exchange.

According to one aspect of the present invention, a square tubular frame extending in the first axial direction and a direction formed inside the frame, extending in the first axial direction and orthogonal to the first axial direction. A plurality of partition walls forming a plurality of square tubular cells by being arranged at regular intervals in the second axis direction and the third axis direction which are orthogonal to each other, and the second axis among the plurality of cells. A plurality of first slits formed by removing the partition wall on the first end face side of one of the pair of end faces in the first axis direction of the plurality of first cells arranged in every other row in the direction, and the plurality of first cells. The partition wall on the other second end face side of the pair of end faces in the uniaxial direction of the plurality of second cells arranged in the row in the second axial direction different from the row of the plurality of first cells in the cell. A molding step of molding a molded body having a plurality of second slits formed by removing the above with a ceramic raw material, and a firing step of obtaining a heat exchanger of the ceramic sintered body by firing the molded body. In the molding step, the opening area or opening width of the plurality of first slits and the plurality of second slits at the position where the partition wall is provided, and the plurality of first slits and the plurality of first slits. The opening area or opening width of the two slits at the position where the partition wall is not provided, the length of each of the plurality of first slits and the plurality of second slits in the third axial direction, and the plurality of cells. The shape of the molded body is determined in advance from the relationship between the length of each in the third axial direction and the design efficiency of heat exchange, and after molding the frame and the partition wall, the above-mentioned first cell of the plurality of cells is described. Provided is a method for manufacturing a heat exchanger, which comprises removing the partition wall on the first axial direction side and the partition wall on the second axial direction side of the plurality of second cells to form the molded body. To.

According to one aspect of the present invention, it is a heat exchanger of a ceramic sintered body, which is a square tubular frame extending in the first axial direction and is formed inside the frame and is formed in the first axial direction. A plurality of partition walls extending and forming a plurality of square tubular cells by being arranged at regular intervals in the second axis direction and the third axis direction which are orthogonal to the first axis direction and are orthogonal to each other. And, the partition wall on the first end face side of one of the pair of end faces in the first axis direction of the plurality of first cells arranged in every other row in the second axis direction among the plurality of cells is removed. A pair of end faces in the uniaxial direction of the first slit formed and a plurality of second cells arranged in a row in the second axial direction different from the row of the plurality of first cells among the plurality of cells. It is characterized by having a plurality of second slits formed by removing the partition wall on the other second end face side, and satisfying the equation (1) according to the degree of achievement η of the design efficiency of heat exchange. A heat exchanger is provided.

η: Achievement of heat exchange design efficiency (-)
L / d: Number of cells L: Length of the first slit and the second slit in the third axis direction (mm)
d: Length (mm) of each of the plurality of cells in the third axis direction
A': Opening area (mm ² ) at the position where the partition walls of the first slit and the second slit are provided.
A: Opening area (mm ² ) at the position where the partition walls of the first slit and the second slit are not provided.

According to one aspect of the present invention, there is provided a method for manufacturing a heat exchanger and a heat exchanger capable of increasing the efficiency of heat exchange.

It is a perspective view which shows the heat exchanger which concerns on 1st Embodiment of this invention. It is a drawing which shows the heat exchanger which concerns on 1st Embodiment, (A) is a front view, (B) is a rear view. It is sectional drawing in the center in the x-axis direction which shows the heat exchanger which concerns on 1st Embodiment. It is a partial cross-sectional view on the x-axis positive direction side which shows the heat exchanger which concerns on 1st Embodiment, and is the line arrow view | FIG. It is a partial cross-sectional view which shows the heat exchanger which concerns on 1st Embodiment, (A) is a view | FIG. .. It is sectional drawing which shows the heat exchanger which concerns on 1st Embodiment, (A) is sectional drawing of 1st cell, (B) is sectional drawing of 2nd cell. It is explanatory drawing which shows the manufacturing method of the heat exchanger which concerns on 1st Embodiment, (A) is a perspective view of a molded body 71, (B) is a perspective view of a molded body 72, (C) is a molding. It is a perspective view of the body 73. It is a perspective view which shows the heat exchanger which concerns on 2nd Embodiment of this invention. It is a drawing which shows the heat exchanger which concerns on 2nd Embodiment, (A) is a front view, (B) is a rear view. It is sectional drawing which shows the heat exchanger which concerns on 2nd Embodiment, (A) is sectional drawing of 1st cell, (B) is sectional drawing of 2nd cell. It is explanatory drawing which shows the manufacturing method of the heat exchanger which concerns on 2nd Embodiment, (A) is a perspective view of a molded body 71, (B) is a perspective view of a molded body 72, (C) is a molding. It is a perspective view of the body 73. It is a graph which shows the result of an Example.

In the following detailed description, many specific details are described by way of illustration of embodiments of the invention to provide a complete understanding of the invention. However, it is clear that one or more embodiments can be implemented without the description of such particular details. Also, the drawings are schematic representations of well-known structures and equipment for the sake of brevity.

<First Embodiment>
(Heat exchanger)
First, the heat exchanger 1 according to the first embodiment will be described with reference to FIGS. 1 to 6. The heat exchanger 1 is a ceramic sintered body that recovers heat from high-temperature exhaust gas, wastewater, and the like. As shown in FIGS. 1 and 2, the heat exchanger 1 includes a frame body 2, a partition wall 3, a first slit 41, a second slit 42, a first sealing portion 51, and a second sealing portion. A 52, a first opening 61, and a second opening 62 are provided.

The height direction of the frame 2 is parallel to the x-axis direction (first axis direction), and the side surface of the frame 2 is in the y-axis direction (third axis direction) or the z-axis direction (third axis direction) in a rectangular cross section orthogonal to the x-axis direction. It has a square tubular shape extending in the biaxial direction). In the drawings, the x-axis, y-axis, and z-axis are axes orthogonal to each other.
As shown in FIG. 3, the partition wall 3 is a wall formed so as to extend in the x-axis direction inside the frame body 2, and is arranged in rows at regular intervals in the y-axis direction and the z-axis direction, respectively. It is formed in a grid pattern. The inside of the frame body 2 is partitioned by the partition wall 3 in a grid pattern, and each of the partitioned areas is referred to as a cell 31. That is, the heat exchanger 1 has a plurality of cells 31 provided side by side in the y-axis direction and the z-axis direction inside. The length of the cell 31 in the z-axis direction, which is the spacing in the z-axis direction of the partition wall 3, is referred to as d, and the length of the cell 31 in the y-axis direction, which is the spacing in the y-axis direction of the partition wall 3, is referred to as w. Further, as will be described later, it is preferable that the length d in the z-axis direction of the cell 31 is larger than the length w in the y-axis direction.

As shown in FIG. 4, the first slit 41 extends in the z-axis direction by removing a plurality of partition walls 3 arranged in the z-axis direction on the x-axis positive direction side inside the heat exchanger 1. It is a region (space) formed by. The first slit 41 is formed in every other row of the rows arranged in the y-axis direction among the plurality of cells 31.
The second slit 42 extends in the z-axis direction like the first slit 41 by removing a plurality of partition walls 3 arranged in the z-axis direction on the x-axis negative direction side inside the heat exchanger 1. It is a region (space) formed by. The second slit 42 is formed in a row of the plurality of cells 31 in which the first slit 41 is not formed for the rows arranged in the y-axis direction. Further, the cell 31 in which the first slit 41 is formed is referred to as a first cell 311 and the cell 31 in which the second slit 42 is formed is referred to as a second cell 312. Inside the heat exchanger 1, the first cell 311 is formed. And the second cell 312 are formed side by side alternately in the y-axis direction, one row at a time, as shown in FIGS. 2 (A) and 2 (B).

In the first slit 41 and the second slit 42 (hereinafter, also simply referred to as “slit”), the partition walls 3 arranged in the z-axis direction are not completely removed in the y-axis direction, and the molding accuracy at the time of processing described later is described. Depending on the situation, it is removed with a part left. That is, the first slit 41 and the second slit 42 have a shape in which the inner wall surface protrudes inward from the position where the partition wall 3 is not provided at the y-axis direction position where the partition wall 3 is provided. The width in the axial direction is narrow. Therefore, the area of the opening region in the xy cross section at the z-axis direction position where the partition wall 3 of each slit is not provided is xy at the z-axis direction position where the partition wall 3 of each slit is provided. The area of the opening area in the cross section becomes smaller. In the example shown in FIG. 5, FIG. 5A shows a partial cross-sectional view at a position where the partition wall 3 is provided, and FIG. 5B shows a partial cross-sectional view at a position where the partition wall 3 is not provided. As shown in FIG. 5A, at the position where the partition wall 3 is provided, the opening region of the first slit 41 is defined as a rectangular region having a length a in the x-axis direction and a length b ₁ in the y-axis direction. .. Further, as shown in FIG. 5B, at the position where the partition wall 3 is not provided, the opening region of the first slit 41 has a length a in the x-axis direction and a length b ₂ (b ₂ ) in the y-axis direction. > B ₁ ) is defined as a rectangular area. The x-axis negative side end of the opening region at the position where the partition wall 3 is not provided is the same as the x-axis negative side end of the opening region at the position where the partition wall 3 is provided.

As shown in FIG. 2A, the first sealing portion 51 is the first cell 311 provided with the first slit 41 among the end faces (first end faces) on the x-axis positive direction side of the frame body 2. It is provided by sealing the opening area. That is, in the first cell 311, with respect to the pair of end faces in the x-axis direction, the end faces on the positive direction side of the x-axis are sealed via the first slit 41, and the end faces on the negative direction side of the x-axis are opened.
As shown in FIG. 2B, the second sealing portion 52 is the second cell 312 provided with the second slit 42 among the end faces (second end faces) on the negative side of the x-axis of the frame body 2. It is provided by sealing the opening area. That is, in the second cell 312, with respect to the pair of end faces in the x-axis direction, the end faces on the negative direction side of the x-axis are sealed via the second slit 42, and the end faces on the positive direction side of the x-axis are opened.

A plurality of first openings 61 are formed side by side in the y-axis direction at a position on the x-axis positive direction side of the side surface of the frame body 2 on the z-axis positive direction side where the first slit 41 is formed. The first opening 61 has the same shape and area as the opening region of the first slit 41 at the position where the partition wall 3 is provided.
A plurality of second openings 62 are formed side by side in the y-axis direction at positions on the x-axis negative direction side of the side surface of the frame body 2 on the z-axis positive direction side where the second slit 42 is formed. The second opening 62 has the same shape and area as the opening region of the second slit 42 at the position where the partition wall 3 is provided.

In the heat exchanger 1 according to the first embodiment, fluids having different temperatures (high temperature fluid and low temperature fluid) are allowed to flow into the first cell 311 and the second cell 312 from both end faces in the x-axis direction, respectively. Heat exchange of fluid. At this time, in the first cell 311, one of the fluids flows in from the opening on the negative side of the x-axis and flows out from the first opening 61. On the other hand, in the second cell 312, the other fluid flows in from the opening on the positive direction side of the x-axis and flows out from the second opening 62. Then, heat exchange of the fluid flowing into the first cell 311 and the second cell 312 is performed through the partition wall 3.

Further, the heat exchanger 1 has a first area A'(mm ² ), a second area A (mm ² ), a length d (mm) of the cell 31 in the z-axis direction, and a first slit 41 and a second slit. It is preferable that the length L (mm) of 42 in the z-axis direction satisfies the following equation (1). The first area A'is the opening area of the xy cross section at the position where the partition wall 3 of the first slit 41 and the second slit 42 is provided. The first area A'is the opening area of the xy cross section of each slit of the first slit 41 and the second slit 42 at the position in the z-axis direction where the partition wall 3 is provided, and is a in FIG. 5 (A). It is _an area obtained by × b1. Further, the second area A is the opening area of the cross section of each slit at the position in the z-axis direction in which the partition wall 3 is not provided, and is the area obtained by a × b ₂ in FIG. 5 (B). As shown in FIG. 6, the length d of the cell 31 in the z-axis direction is the distance between adjacent cells 31 in the z-axis direction or between the center of the cell 31 and the edge of the frame 2 in the z-axis direction. Further, the length L of the first slit 41 and the second slit 42 in the z-axis direction is the distance between the centers of both end walls of the frame body 2 in the z-axis direction in the z-axis direction, as shown in FIG. Further, in the present embodiment, the shapes and dimensions of the plurality of cells 31 are the same, and the shapes and dimensions of the first slit 41 and the second slit 42 are also the same. That is, the length d, the first area A'and the second area A are the same in any cell 31 or any slit. Since the frame body 2 and the cell 31 have the same thickness in the present embodiment, the length L is a value obtained by multiplying the length d by the number of cells 31 in the z-axis direction by an integer. In addition, in the equation (1), η indicates the degree of achievement of the design efficiency of heat exchange, and the first slit 41 with respect to the heat recovery rate when the drift in the first slit 41 and the second slit 42 is not taken into consideration. And the ratio of the heat recovery rate when the drift in the second slit 42 is taken into consideration. That is, η indicates how much the efficiency is reduced due to the drift. The degree of achievement η of the heat exchange design efficiency is preferably 0.90 or more, and more preferably 0.95 or more. That is, the left side of the equation (1) is preferably 0.90 or more, and more preferably 0.95 or more. In the equation (1), the ratio (A'/ A) of the first area A'to the second area A is in the range of 0 to 1. Therefore, since the exponential part of Eq. (1) always shows a negative value, the smaller (L / d) and the larger (A' / A), the larger the value on the left side of Eq. (1). You can see that.

In the heat exchanger 1 according to the first embodiment, the value (L / d) obtained by dividing the length L of the first slit 41 and the second slit 42 in the z-axis direction by the cell length d in the z-axis direction, that is, , The degree of achievement of heat exchange design efficiency is adjusted by adjusting the number of cells (L / d) in the z-axis direction and the ratio of the first area A'to the second area A (A'/ A). In this adjustment method, as will be described later, the upper limit of the ratio (A'/ A) is determined by the molding accuracy at the time of manufacturing. Therefore, in a normal case, the number of cells (L / d) is determined according to the molding accuracy. .. The number of cells (L / d) corresponds to the number of partition walls 3 provided in the z-axis direction of the heat exchanger 1, that is, the number of irregularities after removing the partition walls 3 in each slit. Further, usually, the length of the cell 31 in the y-axis direction is determined in advance according to conditions such as the molding accuracy of the heat exchanger 1 and the pressure loss according to the type of fluid, and the pressure loss does not become a problem. It is preferable to make it smaller. Then, in a normal case, in order to make the degree of achievement η of the heat exchange design efficiency 0.90 or more, the cross-sectional shape orthogonal to the x-axis direction of the cell 31 is z rather than the length w in the y-axis direction. It is preferable that the length d in the axial direction is a long rectangular shape. In the conventional heat exchanger as shown in Patent Document 1, the cross-sectional shape of the cell is square from the viewpoint of simplicity of manufacturing and design and strength. However, in the first embodiment, the number of cells (L / d) in the z-axis direction is determined so as to satisfy the equation (1), and the cross-sectional shape is preferably in the z-axis direction rather than the length w in the y-axis direction. By forming a rectangle having a long length d, it is possible to suppress the occurrence of drift due to the unevenness of the inner surface of the slit that occurs during slit processing, and it is possible to improve the degree of achievement of the design efficiency of heat exchange.

Further, in the first embodiment, by forming the first opening 61 and the second opening 62 on the same side surface, the fluid passing through the first cell 311 and the fluid passing through the second cell 312 are in the z-axis direction. The difference in flow rate due to the difference between the two can be reduced. The closer the cell 31 is to the opening through which the fluid flows, the higher the flow rate. For example, in the cell 31 of the first embodiment, the cell 31 on the z-axis positive direction side, which is the side on which the first opening 61 and the second opening 62 are provided, is more than the cell 31 on the z-axis negative direction side. The flow rate of the flowing fluid increases. Further, even when a drift occurs, if the cell 31 has the same z-axis direction, the change in the flow rate due to the drift is the same, so that the fluid passing through the first cell 311 and the fluid passing through the second cell 312 are the same. The difference in flow rate due to the difference in the z-axis direction with and can be reduced. As a result, heat exchange can be performed more effectively.
The heat exchanger 1 according to the first embodiment may be used alone when it is actually used, and a plurality of heat exchangers 1 may be used alone in the x-axis direction and the y-axis direction depending on the intended use. And may be used as an aggregate arranged in at least one of the z-axis directions.

(Manufacturing method of heat exchanger)
Next, a method for manufacturing the heat exchanger 1 according to the first embodiment will be described. In the present embodiment, first, referring to FIG. 7, a molded body 7 having the same shape as the heat exchanger 1 is molded from the ceramic raw material (molding step). The ceramic raw material becomes ceramics by firing. The ceramics used as the heat exchanger 1 are not particularly limited as long as they can be applied to the environment in which the heat exchanger 1 is used. For example, as the ceramics used as the heat exchanger 1, one of ceramics such as silicon carbide, silica, alumina, silicon nitride, boron nitride, magnesia, zirconia, titania, hafnia, yttria, and lanthana should be used alone. Or you can use two or more of them together. It is preferable to use silicon carbide because it has excellent heat resistance. When silicon carbide is used as the ceramics of the heat exchanger 1, as the ceramic raw material, a raw material containing silicon carbide powder or a raw material containing a silicon source and a carbon source for producing silicon carbide can be used. When a silicon source for producing silicon carbide and a raw material containing a carbon source are used, firing is performed while reacting and generating silicon carbide at the time of firing.

In the molding step, first, the number of the first area A', the second area A, and the partition wall 3 in the z-axis direction of the heat exchanger 1 is determined according to the degree of achievement η of the heat exchange design efficiency. .. The number of cells is obtained by dividing by the length d of the cells including the partition wall (L / d) when the length in the z-axis direction is fixed. The degree of achievement η of the heat exchange design efficiency is a value determined by the above equation (1). In order to increase the degree of achievement η of the design efficiency of heat exchange, increase the ratio (A'/ A) of the first area A'to the second area A, or decrease the number of cells (L / d). There is a need.

In order to increase the ratio (A'/ A), it is necessary to increase the first area A', and the upper limit is determined according to the molding accuracy in the molding step. That is, the ratio (A'/ A), that is, the first area A'is preferably set to a value as large as possible according to the molding accuracy. When the first slit 41 and the second slit 42 are formed by removing the partition wall 3 as described later, it is difficult to form the inner surface between the cells 31 arranged in the z-axis direction in each slit flat. Yes, it is inevitable that unevenness will occur. However, this unevenness causes the drift of the fluid in the heat exchanger 1 after firing. Therefore, from the viewpoint of improving the efficiency of heat exchange, it is effective to reduce the unevenness, that is, to increase the ratio (A'/ A) (approach 1).

In order to reduce the number of cells (L / d), the length L of the first slit 41 and the second slit 42 is determined by the size of the heat exchanger 1 itself, so that the z-axis of the cell 31 It is necessary to increase the length d in the direction. If the length d of the cell 31 in the z-axis direction is made too large, the strength of the heat exchanger 1 will decrease. Therefore, the upper limit of the length d is determined according to the required strength and material. Since it is preferable to increase the length d, the cross-sectional shape of the cell 31 orthogonal to the x-axis direction is a rectangle in which the length d in the z-axis direction is longer than the length w in the y-axis direction. Is preferable. The length w of the cell 31 in the y-axis direction is the distance between adjacent cells 31 in the y-axis direction or the center between the cell 31 and the end wall of the frame 2 in the y-axis direction, similarly to the length d. Defined.

In the molding step, after determining the shape conditions of the heat exchanger 1, as shown in FIG. 7A, the molded body 71 (7) in which the frame body 2 and the partition wall 3 are integrally formed using a ceramic material. ) Is formed. At this time, the molded body 71 formed has a shape in which the first slit 41 and the second slit 42 are not formed, and the partition wall 3 and the frame body 2 are formed to have the same length in the x-axis direction in the longitudinal direction. Will be done. The length d of the cell 31 of the molded body 71 in the z-axis direction and the length L of the first slit 41 and the second slit 42 in the z-axis direction are predetermined lengths as described above.

Next, as shown in FIG. 7B, the partition walls 3 arranged in the z-axis direction on both sides of the x-axis are removed to form the first slit 41 and the second slit 42, and the molded body 72 is formed. (7) is formed. At this time, the first slit 41 is formed by removing the partition walls 3 arranged in the z-axis direction on the x-axis positive direction end face side of the row of the first cell 311 of the molded body 71. Further, the second slit 42 is formed by removing the partition wall 3 arranged in the z-axis direction on the x-axis negative direction end face side of the row of the second cell 312 of the molded body 71. The first area A', which is the area of the opening region of the partition wall 3 formed by the removal, has a predetermined size as described above. When the partition wall 3 of the molded body 71 is removed as in the present embodiment, the partition wall 3 before firing is removed, so that the partition wall 3 is removed as compared with the case where the partition wall after firing is removed as in Cited Document 1, for example. Can be removed with high accuracy, and the ratio (A'/ A) can be increased. Further, at this time, as shown in FIG. 7B, the position where the first slit 41 and the second slit 42 are formed on the end face of the frame body 2 on the positive direction side of the z-axis is set along with the removal of the partition wall 3. The first opening 61 and the second opening 62 are formed by removing the first slit 41 and the second slit 42 in the same manner as in the shape of the first slit 41 and the second slit 42.

Further, as shown in FIG. 7C, a first sealing portion 51 made of a ceramic raw material and a first sealing portion 51 made of a ceramic raw material are provided on the end faces on the side where each slit of the row in which the first slit 41 and the second slit 42 are formed are formed. 2 By providing the sealing portion 52, the molded body 73 (7) is molded. The molded molded body 73 has the same shape as the heat exchanger 1 shown in FIGS. 1 and 2. The first sealing portion 51 and the second sealing portion 52 are preferably made of the same material as the frame body 2 and the partition wall 3, but may be made of other ceramic raw materials. The molding process is completed by molding the molded body 73.

After the molding step, the molded body 7 formed in the molding step is fired to obtain a heat exchanger 1 which is a sintered body. In the firing of the molded body 7, conditions such as the firing atmosphere, firing temperature and time are appropriately set according to the type of the ceramic raw material. For example, when silicon carbide is used as the ceramic raw material of the heat exchanger 1, firing is performed in a non-oxidizing atmosphere. The non-oxidizing atmosphere is an inert gas atmosphere such as argon or helium, a nitrogen gas atmosphere, a mixed gas atmosphere thereof, or a vacuum atmosphere.

After the firing, if necessary, it may be coated with an antioxidant and heat-treated. Antioxidants are those that become silicic acid-based glass by heating, and in addition to silicon dioxide, alkali metal components such as sodium oxide, potassium oxide, and potassium carbonate, alkaline earth metal components such as calcium oxide and calcium carbonate, and silicon ( It can contain (single silicon), boron oxide, aluminum oxide, aluminum hydroxide and the like. The antioxidant becomes an antioxidant layer of silicic acid-based glass that adheres to the surface of the partition wall 3 by being heated during firing. Here, since the alkali metal component and the alkaline earth metal component melt or soften silicon dioxide under heating, the adhesion and permeability to the partition wall can be adjusted by their contents. Further, the coefficient of thermal expansion of the silicic acid-based glass can be adjusted by the content of boron oxide. In addition, the strength of the silicate-based glass can be adjusted by the content of aluminum oxide or aluminum hydroxide (which becomes aluminum oxide when heated).

<Second Embodiment>
(Heat exchanger)
Next, the heat exchanger 1 according to the second embodiment will be described. The heat exchanger 1 according to the second embodiment is a ceramic sintered body that recovers heat from high-temperature exhaust gas, wastewater, or the like, as in the first embodiment. As shown in FIGS. 8 to 10, the heat exchanger 1 includes a frame body 2, a partition wall 3, a first slit 41, a second slit 42, a third slit 43, a fourth slit 44, and a first. It includes a 1-sealing portion 51, a 2nd sealing portion 52, a 3rd sealing portion 53, and a 4th sealing portion 54.

The frame body 2 and the partition wall 3 are the same as those in the first embodiment. That is, inside the square cylindrical frame 2 extending in the x-axis direction, the frame body 2 extends in the x-axis direction and is arranged in rows at regular intervals in the y-axis direction and the z-axis direction, and a plurality of partition walls 3 are provided. By doing so, a plurality of cells 31 are formed. Then, as in the first embodiment, the plurality of rows of the plurality of cells 31 arranged in the z-axis direction are alternately referred to as the first cell 311 and the second cell 312 in the y-axis direction. The first cell 311 and the second cell 312 are cells 31 through which fluids having different temperatures flow.

The first slit 41 is a region formed extending in the z-axis direction by removing a plurality of partition walls 3 arranged in the z-axis direction on the x-axis positive direction side inside the heat exchanger 1. , The same as that of the first embodiment. The first slit 41 is formed in the first cell 311 which is every other row of the rows arranged in the z-axis direction among the plurality of cells 31.
The second slit 42 is a region formed extending in the z-axis direction by removing a plurality of partition walls 3 arranged in the z-axis direction on the x-axis negative direction side inside the heat exchanger 1. , The same as that of the first embodiment. The second slit 42 is formed in the second cell 312, which is a row in which the first slit 41 is not formed among the plurality of cells 31.

The third slit 43 is a region formed extending in the z-axis direction by removing a plurality of partition walls 3 arranged in the z-axis direction on the x-axis negative direction side inside the heat exchanger 1. , The first slit 41 is formed in the first cell 311 which is the cell 31 in which the first slit 41 is formed.
The fourth slit 44 is a region formed extending in the z-axis direction by removing a plurality of partition walls 3 arranged in the z-axis direction on the x-axis positive direction side inside the heat exchanger 1. , The second slit 42 is formed in the second cell 312, which is the cell 31 in which the second slit 42 is formed.

The first slit 41 to the fourth slit 44 are formed by removing the cell 31 in the same manner, and have the same shape and dimensions. That is, the first slit 41 to the fourth slit 44 are formed by similarly removing the plurality of partition walls 3 arranged in the z-axis direction on both the positive and negative end surface sides of the cell 31 in the x-axis direction. To.

The first sealing portion 51 is provided by sealing the end face on the x-axis positive direction side of the frame body 2 on the z-axis negative direction side of the opening region of the first cell 311 provided with the first slit 41. ..
The second sealing portion 52 is provided by sealing the end face on the negative side of the x-axis of the frame body 2 on the negative side of the z-axis of the opening region of the second cell 312 provided with the second slit 42. .. The length in the z-axis direction in which the second sealing portion 52 is provided is the same as the length in the z-axis direction in which the first sealing portion 51 is provided.

The third sealing portion 53 is provided by sealing the z-axis positive direction side of the opening region of the first cell 311 provided with the first slit 41 among the end faces on the x-axis negative direction side of the frame body 2. ..
The fourth sealing portion 54 is provided by sealing the z-axis positive direction side of the opening region of the second cell 312 provided with the second slit 42 among the end faces of the frame body 2 on the x-axis positive direction side. .. The length in the z-axis direction in which the fourth sealing portion 54 is provided is the same as the length in the z-axis direction in which the third sealing portion 53 is provided.

Further, as shown in FIG. 9, the region in the z-axis direction sealed by the third sealing portion 53 and the fourth sealing portion 54 is sealed by the first sealing portion 51 and the second sealing portion 52. It is preferable to set the region excluding the region on the positive direction side of the z-axis. That is, the region sealed by the third sealing portion 53 and the fourth sealing portion 54 and the region sealed by the first sealing portion 51 and the second sealing portion 52 are superimposed in the z-axis direction. It is preferable not to do so. This is because the opening area on the entry side or the exit side of the heat exchanger 1 is reduced, which leads to an increase in pressure loss. Further, the length of the region sealed by the first sealing portion 51 and the second sealing portion 52 in the z-axis direction is the length of the region sealed by the third sealing portion 53 and the fourth sealing portion 54. It is preferably longer than the length in the z-axis direction. The cell 31 in contact with the z-axis direction has a space internally connected in the z-axis direction by each slit, but the cell 31 that seals the entry side of the fluid passes through as compared with the cell 31 that does not seal the entry side. It is possible that the flow rate of the fluid will decrease. Therefore, from the idea of reducing the number of cells 31 having a small passing flow rate as much as possible to improve efficiency, it is preferable to use the region ratio as described above.

That is, in the heat exchanger 1 according to the present embodiment, the first cell 311 opens through the first slit 41 on the z-axis positive direction side and the fourth slit on the z-axis negative direction side with respect to the end face on the x-axis positive direction side. The second cell 312 is opened through 44. Further, in the heat exchanger 1, the second cell 312 is opened through the second slit 42 on the z-axis positive direction side and the first through the third slit 43 on the z-axis negative direction side with respect to the end face on the x-axis negative direction side. The cell 311 is opened.

Further, in the heat exchanger 1, the number of cells (L / d) in the z-axis direction of the first area A', the second area A, and the cell 31 is the same as that of the first embodiment. It is preferable to meet. The first area A'and the second area A are the same in all the slits of the first slit 41 to the fourth slit 44.

In the heat exchanger 1 according to the second embodiment, fluids having different temperatures are allowed to flow into the first cell 311 and the second cell 312 from the z-axis negative direction sides of both end faces in the x-axis direction, thereby causing these two fluids. Heat exchange. At this time, in the first cell 311 as shown in FIG. 10A, the fluid flows in from the opening formed on the z-axis negative direction side of the x-axis negative side end face, and the z of the x-axis positive side end face is z. The fluid flows out from the opening formed on the positive side of the axis. On the other hand, in the second cell 312, as shown in FIG. 10B, the fluid flows in from the opening formed on the z-axis negative direction side of the x-axis positive side end face, and the z-axis of the x-axis negative side end face. The fluid flows out from the opening formed on the positive side. Then, heat exchange of the fluid flowing into the first cell 311 and the second cell 312 is performed through the partition wall 3.

Here, the heat exchanger that recovers heat from high-temperature exhaust gas, wastewater, or the like, such as the heat exchanger 1 according to the first embodiment or the second embodiment, is made of ceramics. However, since the casing that houses the heat exchanger is usually made of metal, contact surfaces of different materials are generated. For this reason, in the inlet and outlet parts where the fluid of the heat exchanger flows in and out, leaks and damage may occur unless a sealing method is taken in consideration of the difference in elongation between the two materials especially when the temperature rises. Become. As a sealing method at such a portion, a method of sandwiching a sealing material between materials and applying surface pressure is generally adopted. And, in order to exhibit sufficient sealing property, the magnitude of the surface pressure applied to the sealing portion is important. In a conventional heat exchanger as described in Patent Document 1, since the inflow direction and the outflow direction of the fluid are oriented in different directions, it is necessary to apply loads in different directions in the ingress and out directions. there were. Further, since the heat exchanger having a honeycomb structure has a structure having a plurality of cells like a bundle of thin tubes, it is strong against a load in a direction parallel to the extending direction of the cells, but a load in a vertical direction. Will be weak. In addition, since ceramics typified by SiC are brittle materials, there is a risk of cracking if a strong load is applied. This also applies to the case of the heat exchanger 1 according to the first embodiment, with respect to the side surfaces in the vicinity of the first opening 61 and the second opening 62 when sealing the discharge direction of the fluid. , It is necessary to apply a load in the direction perpendicular to the cell, which is the direction weak against the load, and seal it. For this reason, there is a possibility that damage due to the load being too strong or leakage due to the load being made too small due to concern about damage may become a problem. Further, when the heat exchangers described in Patent Document 1 are provided with openings on the two opposite side surfaces, the heat exchangers need to be suppressed in the biaxial direction, which complicates the casing and increases the cost. It causes complicated assembly.

On the other hand, in the heat exchanger 1 according to the second embodiment, since the inflow direction and the discharge direction of the fluid are parallel to each other, the load direction is one axis when the heat exchanger 1 is sealed. The direction is parallel to. Further, this load direction is the extension direction of the cell that is structurally strong against the load. Therefore, as compared with the heat exchanger 1 according to the first embodiment and the heat exchanger described in Patent Document 1, a larger load can be applied to the seal portion, and the heat recovery rate due to the reduction in the leak rate can be applied. Can be improved. In addition, it can be expected that the material cost will be reduced due to the wider selection of sealing materials, the manufacturing cost will be reduced due to the small size and simple structure of the casing, and the work at the time of installation will be omitted.

Further, in the heat exchanger 1 according to the second embodiment, as shown in FIG. 10, the flow path of the fluid flowing through the first cell 311 and the flow path of the fluid flowing through the second cell 312 are the same as in the first embodiment. However, if the z-axis direction is the same, the same applies. Therefore, it is possible to reduce the difference in flow rate due to the difference in the z-axis direction between the fluid passing through the first cell 311 and the fluid passing through the second cell 312. As a result, heat exchange can be performed more effectively as in the first embodiment.

(Manufacturing method of heat exchanger)
Next, with reference to FIG. 11, a method for manufacturing the heat exchanger 1 according to the second embodiment will be described. In the present embodiment, first, a molded body 7 having the same shape as the heat exchanger 1 is molded from the ceramic raw material (molding step). In the molding step, first, as in the first embodiment, the first area A'of the heat exchanger 1, the second area A, and the z-axis direction of the cell 31 are determined according to the degree of achievement η of the heat exchange design efficiency. Determine the number of cells (L / d) in.

In the molding step, after determining the shape conditions of the heat exchanger 1, as shown in FIG. 11A, the molded body 71 (7) in which the frame body 2 and the partition wall 3 are integrally formed using a ceramic material. ) Is formed. At this time, the molded body 71 formed has a shape in which the first slit 41 to the fourth slit 44 are not formed, and the partition wall 3 and the frame body 2 are formed to have the same length in the x-axis direction in the longitudinal direction. Will be done. The length d of the cell 31 of the molded body 71 in the z-axis direction and the length L of the first slit 41 and the second slit 42 in the z-axis direction are predetermined lengths as described above.

Next, as shown in FIG. 11B, the partition walls 3 on both ends in the x-axis direction are removed to form the first slit 41 to the fourth slit 44, and the molded body 72 (7) is formed. At this time, the first slit 41 and the third slit 43 are formed by removing the partition wall 3 extending in the y-axis direction on the x-axis positive direction end face side and the negative direction end face side of the row of the first cell 311 of the molded body 71. Will be done. The second slit 42 and the fourth slit 44 are formed by removing the partition wall 3 extending in the y-axis direction on the x-axis negative direction end face side and the positive direction end face side of the row of the second cell 312 of the molded body 71. The first area A', which is the area of the opening region of the partition wall 3 formed by removal, has a predetermined size as described above.

Further, as shown in FIG. 11C, the z-axis negative direction side of the end surface on which the first slit 41 and the second slit 42 are formed, and the z of the end surface on which the third slit 43 and the fourth slit 44 are formed. The molded body 73 (7) is molded by providing the first sealing portion 51 to the fourth sealing portion 54 made of ceramic raw materials on the positive direction side of the shaft. The molded molded body 73 has the same shape as the heat exchanger 1 shown in FIGS. 8 to 10. The first sealing portion 51 to the fourth sealing portion 54 are preferably made of the same material as the frame body 2 and the partition wall 3, but may be made of other ceramic raw materials. The molding process is completed by molding the molded body 73.
After the molding step, as in the first embodiment, the molded body 7 formed in the molding step is fired to obtain a heat exchanger 1 which is a sintered body. In the firing of the molded body 7, conditions such as the firing atmosphere, firing temperature and time are appropriately set according to the type of the ceramic raw material. For example, when silicon carbide is used as the ceramic raw material of the heat exchanger 1, firing is performed in a non-oxidizing atmosphere.

<Modification example>
Although the present invention has been described above with reference to specific embodiments, it is not intended to limit the invention by these explanations. By reference to the description of the invention, one of ordinary skill in the art will appreciate the disclosed embodiments as well as other embodiments of the invention including various modifications. Therefore, it should be understood that the embodiments of the invention described in the claims also include embodiments including these variations described herein alone or in combination.

For example, in the above embodiment, the equation (1) is used, but the present invention is not limited to this example. As described above, the unevenness generated on the inner surface of each slit because the partition wall 3 cannot be completely removed in the molding process causes the efficiency of heat exchange in the heat exchanger 1 to decrease. Therefore, when trying to adjust the efficiency of heat exchange, it is effective to adjust the size and number of the unevenness, and in order to improve the efficiency, the unevenness may be reduced and the number may be reduced. For example, in the heat exchanger 1 according to the first embodiment, the ratio (A'/ A) is such that if the thickness of the first sealing portion 51 and the second sealing portion 52 is constant in the z-axis direction, each slit Corresponds to the ratio of the opening width, which is the length in the y-axis direction, to the position where the partition wall 3 is provided and the position where the partition wall 3 is not provided. That is, the ratio of the opening width may be used instead of the ratio (A'/ A) in the formula (1). Further, when determining the shape of the heat exchanger 1, the cross-sectional shape orthogonal to the x-axis direction of the cell 31 has a length in the z-axis direction rather than a length in the y-axis direction without using the equation (1). It may have a long rectangular shape. In this case, the upper limit of the length of the cross section of the cell 31 in the z-axis direction is determined according to the strength required for the heat exchanger 1 as in the above embodiment. By doing so, it is possible to suppress the occurrence of drift of the fluid passing through the slit and improve the efficiency of heat exchange, as compared with the case where a heat exchanger having a square cross-sectional shape of the cell is manufactured with the same molding accuracy. Can be improved.

Further, in the above embodiment, the first area A'and the second area A of the first slit 41 to the fourth slit 44 are the same, but the present invention is not limited to this example. The first area A'and the second area A may be different depending on the difference in the slits and the position of the slits in the z-axis direction. In this case, as the first area A'and the second area A used in the equation (1), those obtained by averaging the first area A'and the second area A at each position can be used.
Further, in the above embodiment, the thickness of the frame 2 and the thickness of the cell 31 are the same, but the present invention is not limited to this example. For example, the frame body 2 and the cell 31 may have different thicknesses. In this case, the length L may be defined according to the thickness of the cells 31 so that (L / d) is the number of cells in the z-axis direction regardless of the thickness of the frame body 2.

Next, the examples carried out by the present inventors will be described. In the embodiment, for the heat exchanger 1 similar to the first embodiment, the number of cells (L / d) and the ratio (A'/ A) are changed, respectively, and the degree of achievement η of the heat exchange design efficiency is changed. Asked. In the embodiment, the degree of achievement η of the heat exchange design efficiency is the calculated value of the heat recovery rate when the influence of the drift due to the unevenness of the first slit 41 and the second slit 42 is taken into consideration. 2 It is a value divided by the calculated value of the heat recovery rate when there is no unevenness on the inner surface of the slit 42.

The results of the examples are shown in FIG. In FIG. 12, the horizontal axis indicates the number of cells (L / d), and the vertical axis indicates the degree of achievement η of the heat exchange design efficiency. Further, α is a ratio (A'/ A). As shown in FIG. 12, the degree of achievement η of the heat exchange design efficiency increases as the number of cells (L / d) decreases, and the heat exchange design efficiency increases as the ratio (A'/ A) increases. It was confirmed that the achievement level η of was improved. In addition, it was confirmed that this calculation result can be reproduced accurately by using the relation of the equation (1). That is, in order to control the degree of achievement η of the heat exchange design efficiency, it is effective to adjust the number of cells (L / d) and the ratio (A'/ A), and it is effective to use the equation (1). It was confirmed that the achievement degree η of the design efficiency of the target heat exchange can be obtained by making this adjustment.

1 Heat exchanger 2 Frame body 3 Partition 31 Cell 311 1st cell 312 2nd cell 41 1st slit 42 2nd slit 43 3rd slit 44 4th slit 51 1st sealing part 52 2nd sealing part 53 3rd Sealing part 54 4th sealing part 61 1st opening 62 2nd opening 7,71,72,73 Molded body

Claims (5)

A square tubular frame extending in the first axial direction, a second axial direction formed inside the frame, extending in the first axial direction, orthogonal to the first axial direction, and orthogonal to each other. A plurality of partition walls forming a plurality of square tubular cells by arranging them in rows at regular intervals in the third axis direction, and a plurality of cells arranged in every other row in the second axis direction among the plurality of cells. A plurality of first slits formed by removing the partition wall on the first end face side of one of the pair of end faces in the first axial direction of the first cell, and the plurality of first cells among the plurality of cells. A plurality of second cells arranged in a row in the second axis direction different from the row of cells, formed by removing the partition wall on the other second end face side of the pair of end faces in the first axis direction. The molding process of molding the molded body having the second slit of the above with a ceramic raw material, and
A firing step of obtaining a heat exchanger of a ceramic sintered body by firing the molded body,
Equipped with
In the molding step, the opening area or opening width of the plurality of first slits and the plurality of second slits at a position where the partition wall is not provided, and the plurality of first slits at a position where the partition wall is provided. The opening area or opening width of the slit and the plurality of second slits, the length of each of the plurality of first slits and the plurality of second slits in the third axial direction, and the first of the plurality of cells. From the relationship between the length in the triaxial direction and the heat exchange design efficiency, the shape of the molded body is determined in advance so as to satisfy the equation (1) according to the achievement degree η of the heat exchange design efficiency, and the frame body. And, after molding the partition wall, the partition wall arranged in a row in the second axial direction on the first end face side of the plurality of first cells, and the second end face side of the plurality of second cells. The partition wall arranged in a row in the biaxial direction is removed to form the molded body, and the molded body is formed.
A method for manufacturing a heat exchanger , wherein the degree of achievement η of the heat exchange design efficiency is 0.90 or more .

η: Achievement of heat exchange design efficiency (-)
L / d: Number of cells L: Length (mm) of each of the plurality of first slits and the plurality of second slits in the third axis direction.
d: Length (mm) of each of the plurality of cells in the third axis direction
A': Each opening area (mm ² ) at the position where the partition walls of the plurality of first slits and the plurality of second slits are provided.
A: Each opening area (mm ² ) at a position where the partition walls of the plurality of first slits and the plurality of second slits are not provided. In the molding step, when determining the shape of the molded body, the cross-sectional shape of the plurality of cells orthogonal to the first axial direction is longer in the third axial direction than the length in the second axial direction. The method for manufacturing a heat exchanger according to claim 1, wherein the heat exchanger has a long rectangular shape. In the molding process,
A plurality of first sealing portions for sealing the first end faces of the plurality of first cells, and a plurality of first sealing portions.
A plurality of second sealing portions for sealing the second end faces of the plurality of second cells, and a plurality of second sealing portions.
An opening formed on the end face on the third axial direction side of the frame, on the first end face side of the region where the first cell is formed and on the second end face side of the region where the second cell is formed. Department and
The method for producing a heat exchanger according to claim 1 or 2 , further comprising forming the molded body. In the molding process,
A plurality of third slits formed by removing the partition wall on the second end surface side of the plurality of first cells, and a plurality of third slits.
A plurality of fourth slits of the plurality of second cells formed by removing the partition wall on the first end face side, and a plurality of fourth slits.
A plurality of first sealing portions for sealing the unidirectional side of the first end surface of the plurality of first cells parallel to the third axial direction.
A plurality of second sealing portions for sealing the one-way side of the second end surface of the plurality of second cells.
A plurality of third sealing portions for sealing the other direction side opposite to the one direction side of the second end surface of the plurality of first cells.
A plurality of fourth sealing portions for sealing the other direction side of the first end surface of the plurality of second cells.
The method for producing a heat exchanger according to any one of claims 1 or 2 , further comprising forming the molded body. It is a heat exchanger of a ceramic sintered body.
A square cylindrical frame extending in the first axis direction,
It is formed inside the frame, extends in the first axial direction, and is arranged at regular intervals in the second axial direction and the third axial direction which are orthogonal to the first axial direction and are orthogonal to each other. With multiple partition walls that form multiple cells in the shape of a square tube,
It is formed by removing the partition wall on the first end face side of one of the pair of end faces in the first axis direction of the plurality of first cells arranged in every other row in the second axis direction among the plurality of cells. With multiple first slits
Of the plurality of cells, the other second end face side of the pair of end faces in the first axis direction of the plurality of second cells arranged in the row in the second axis direction different from the row of the plurality of first cells. A plurality of second slits formed by removing the partition wall of the
Have,
According to the degree of achievement η of the design efficiency of heat exchange, the equation (1) is satisfied.
A heat exchanger characterized in that the degree of achievement η of the design efficiency of heat exchange is 0.90 or more .

η: Achievement of heat exchange design efficiency (-)
L / d: Number of cells L: Length (mm) of each of the plurality of first slits and the plurality of second slits in the third axis direction.
d: Length (mm) of each of the plurality of cells in the third axis direction
A': Each opening area (mm ² ) at the position where the partition walls of the plurality of first slits and the plurality of second slits are provided.
A: Each opening area (mm ² ) at a position where the partition walls of the plurality of first slits and the plurality of second slits are not provided.

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