JP7790167B2 - Laminate and heat exchanger - Google Patents

Description

The present invention relates to a laminate that can be used in a heat exchanger, and a heat exchanger equipped with the laminate.

One type of heat exchanger is a stacked microchannel heat exchanger. A stacked microchannel heat exchanger is formed, for example, by a laminate consisting of alternately stacked heat transfer plates with high-temperature fluid channels and heat transfer plates with low-temperature fluid channels, sandwiched between floor and ceiling panels. The floor, heat transfer plates, and ceiling panels are each integrated by diffusion bonding. For example, the floor, heat transfer plates, and ceiling panels are each stacked in advance, and then the floor, heat transfer plates, and ceiling panels are pressurized and heated from above and below in a vacuum using a pressure jig, thereby eliminating the interfaces and forming an integrated laminate (see, for example, Patent Document 1).

In some cases, external piping communicating with the high-temperature or low-temperature fluid flow path is bonded to the top surface (ceiling plate) of the laminate. During the diffusion bonding process, the floor plate, heat transfer plate, and ceiling plate are each pressed from above and below using a pressure jig. However, if external piping is placed on the top surface of the laminate, the external piping gets in the way, making it difficult to uniformly press the floor plate, heat transfer plate, and ceiling plate with the pressure jig. For this reason, the external piping is bonded to the laminate after the integrated laminate is formed. One method for bonding external piping to the laminate is flame brazing (torch brazing), in which the members to be joined are heated with a burner flame (see, for example, Patent Document 2).

Japanese Patent Application Laid-Open No. 2018-096666 Japanese Patent Application Laid-Open No. 2021-134946

In the above-mentioned brazing process, for example, a ceiling panel with a hole for inserting the external piping is laminated together with a floor panel and a heat transfer plate, and a laminate is formed by diffusion bonding. This results in a laminate with a hole for inserting the external piping on the top surface of the laminate. The external piping is then inserted into the hole, and brazing material is placed at the joint between the external piping and the hole. After that, the external piping and the laminate near this joint are heated with a burner. This melts the brazing material and flows into the gap between the external piping and the hole, and the external piping and the laminate are then joined by cooling.

However, the heat capacity of the external piping may be smaller than that of the laminate, which is the base material. For example, if the external piping and the laminate are made of the same material, stainless steel, and the same amount of heat is applied to parts with the same specific heat, the temperature of the laminate, which has a larger mass, will rise more slowly than that of the external piping. Therefore, when the external piping and the laminate are heated with a burner, the temperature of the external piping will quickly reach the melting temperature of the brazing material, but the temperature of the laminate may not rise sufficiently to a temperature where brazing is possible.

As a result, the brazing material may not flow sufficiently between the external piping and the laminate, resulting in a poor bond between the two. One method involves using a burner to continue heating the external piping and the laminate until the temperature of the laminate reaches a sufficient temperature for brazing. However, this method requires long periods of burner heating, which can lead to deformation of the external piping or the laminate, or to overheating, which can cause the brazing material to oxidize or flow too much, resulting in poor brazing.

In light of the above circumstances, the object of the present invention is to provide a laminate that allows for good brazing when joining the base material laminate to external piping by brazing, and a heat exchanger equipped with such a laminate.

In order to achieve the above-mentioned object, one embodiment of the present invention provides a laminate comprising a protective plate and a heat transfer plate including a heat exchange area in which a flow path is formed, and the protective plate and the heat transfer plate are joined by diffusion bonding.
The protective plate is
a main body plate portion that covers at least the heat exchange area in a stacking direction in which the protection plate and the heat transfer plate are stacked;
the main body plate portion is separated from the annular portion by a slit portion;
a rib portion connecting the annular portion and the main body plate portion,
The annular portion has a hole, and the hole communicates with the flow path.

This type of laminate allows for good brazing when joining the base material laminate to external piping by brazing.

In the above-described laminate, the protective plate has a first main surface joined to the heat transfer plate, a second main surface opposite the first main surface, and a side surface connected to the first main surface and the second main surface, and the protective plate may be provided with an open hole on the side surface that connects the slit portion to the outside of the laminate.

This type of laminate allows for better brazing when joining the base laminate and external piping by brazing.

In the above-mentioned laminate, the protective plate may include a first protective plate portion laminated on the heat transfer plate in the stacking direction, and a second protective plate portion laminated on the first protective plate portion in the stacking direction, and the open hole may be provided in the second protective plate portion.

This type of laminate allows for better brazing when joining the base laminate and external piping by brazing.

In the above laminate, the hole in the protective plate may be provided with a locking portion that stops the insertion of the external piping partway through the hole when the external piping is inserted into the hole.

This type of laminate allows for better brazing when joining the base laminate and external piping by brazing.

In the above laminate, the hole may include a first hole formed in the first protective plate and a second hole formed in the second protective plate, and the inner diameter of the first hole may be smaller than the inner diameter of the second hole.

This type of laminate allows for better brazing when joining the base laminate and external piping by brazing.

In the above-mentioned laminate, the second protective plate portion may be formed from a plurality of plate-shaped members, and at least one of the plurality of plate-shaped members may be provided with a discharge groove that communicates with the slit portion.

This type of laminate allows for better brazing when joining the base laminate and external piping by brazing.

In the above-mentioned stack, each of the plurality of plate-like members includes, in the stacking direction, at least a first main body plate portion covering the first heat exchange area and the second heat exchange area, a first annular member separated from the first main body plate portion by a slit portion, and a first rib member connecting the first annular member and the first main body plate portion. The thickness of the first rib member is thinner than the thickness of the first main body plate portion, and the discharge groove may be formed by thinning a portion of the main body plate portion, with the first rib member connecting to the portion.

This type of laminate allows for better brazing when joining the base laminate and external piping by brazing.

In the above-mentioned laminate, the discharge groove may be formed on the first protective plate portion and on the first protective plate portion side of the plate member of the plurality of plate members that is joined to the first protective plate portion.

This type of laminate allows for better brazing when joining the base laminate and external piping by brazing.

In the above-mentioned stack, the discharge groove may be provided in at least two of the plurality of plate-like members that are joined to each other in the stacking direction, and the discharge grooves provided in the at least two plate-like members may face each other in the stacking direction.

This type of laminate allows for better brazing when joining the base laminate and external piping by brazing.

The above-mentioned laminate may have multiple rib portions.

This type of laminate allows for better brazing when joining the base laminate and external piping by brazing.

In order to achieve the above object, a heat exchanger according to one aspect of the present invention comprises:
The laminate;
an external pipe inserted into the hole;
a bonding material provided between the external pipe and the annular portion.

With this type of heat exchanger, good brazing can be achieved when joining the base material, the laminate, to the external piping by brazing.

As described above, the present invention provides a laminate that allows for good brazing when joining the base material laminate to external piping, and a heat exchanger equipped with the laminate.

FIG. 1 is a schematic perspective view of a laminate according to an embodiment of the present invention. FIG. 2 is a schematic plan view of a laminate according to the present embodiment. FIG. 1 is a schematic perspective view showing a heat exchanger according to an embodiment of the present invention. FIG. 10 is a schematic cross-sectional view showing a state in which an external pipe is joined to a hole portion. 5A and 5B are schematic perspective views of a heat transfer plate included in the heat transfer portion of the laminate, and Fig. 5C is a schematic perspective view of a protection plate portion forming a floor plate of the laminate. FIG. 2 is a schematic perspective view of a protective plate portion that forms a ceiling plate of the laminate. 1A is a schematic diagram illustrating the operation of a comparative example, and FIG. 1B is a schematic diagram illustrating the operation of this embodiment. 10 is a schematic perspective view showing an example in which an open hole that connects a slit portion to the outside of the laminate is provided on the side surface of the ceiling plate. FIG. 9 is a schematic cross-sectional view of the laminate cut in the Z-axis direction along the dashed dotted line L1 in FIG. 8 . 1A is a schematic perspective view of a plate-shaped member, and FIG. 1B is a schematic cross-sectional view of the plate-shaped member cut in the Z-axis direction along a dashed line L1 in FIG. 1A. 10A and 10B are schematic diagrams showing the function of a laminate provided with open holes. 1A is a schematic perspective view showing an example in which a discharge groove is formed on the main surface of a plate-like member that will be the lower surface of the laminate. 1B is a schematic perspective view showing an example in which an area A of the plate-like member surrounded by dashed lines L2 and L3 shown in FIG. 1A has been removed. A schematic oblique view showing a ceiling board in which a plate-shaped member having a discharge groove formed on the upper surface side of the stack and a plate-shaped member having a discharge groove formed on the lower surface side of the stack are joined in the stacking direction. FIG. 10 is a schematic plan view showing an example in which a plurality of rib portions are provided around an annular portion.

Embodiments of the present invention will be described below with reference to the drawings. Furthermore, identical components or components with identical functions may be assigned the same reference numerals, and after describing those components, further description may be omitted as appropriate. Furthermore, the numerical values shown below are examples and are not limited to these examples.

Figure 1 is a schematic perspective view of a laminate according to this embodiment. The laminate 1 shown in Figure 1 is applied, for example, to a laminate-type microchannel heat exchanger. The laminate 1 includes a heat transfer section 2, a floor plate 3, and a ceiling plate 4. The heat transfer section 2 is provided between the floor plate 3 and the ceiling plate 4. The laminate 1 has a substantially rectangular parallelepiped shape. In Figure 1, the side with the ceiling plate 4 is referred to as the upper side, and the side with the floor plate 3 is referred to as the lower side. The floor plate 3 and the ceiling plate 4 are also collectively referred to as protective plates. In the following description, the protective plates will be referred to as the floor plate or the ceiling plate.

The laminate 1 has a principal surface 1u (upper surface), a principal surface 1d (lower surface) opposite to the principal surface 1u, and a side surface 1w connecting the principal surface 1u and the principal surface 1d. The laminate 1 has four side surfaces 1w. The heat transfer section 2 is formed by stacking a heat transfer plate 21A having a flow path (described below) formed therein and a heat transfer plate 21B having a flow path formed therein in the stacking direction (the direction in which the floor plate 3, heat transfer plate 21A, heat transfer plate 21B, and ceiling plate 4 are stacked).

In the laminate 1, holes 2ha-2hd are formed on the main surface 1u. The direction from hole 2ha to hole 2hc and the direction from hole 2hb to hole 2hd are approximately perpendicular. Holes 2ha and 2hc communicate with, for example, a flow path provided in heat transfer plate 21B (described below). Holes 2hb and 2hd communicate with, for example, a flow path provided in heat transfer plate 21A (described below). Details of holes 2ha-2hd will be described below.

In the laminate 1, a floor plate 3 is provided below the heat transfer section 2, and a ceiling plate 4 is provided above the heat transfer section 2. The floor plate 3 includes multiple protective plate portions 31 (for example, two to six, or seven or more; six in Figure 1) stacked in the stacking direction. The ceiling plate 4 includes protective plate portions 41 (first protective plate portions) and protective plate portions 42 (second protective plate portions) stacked in the stacking direction. The protective plate portions 42 further include multiple plate-like members 420 (for example, two to five, or six or more; five in Figure 1). Each of the protective plate portions 31, 41, and 42 is formed from a metal plate, for example, stainless steel.

Each of the multiple protective plate portions 31, the heat transfer plates 21A and 21B that are alternately stacked, the protective plate portions 41, and the multiple plate-like members 420 are joined together by diffusion bonding in the stacking direction. That is, all of the protective plate portions and all of the heat transfer plates included in the stacked body 1 are joined by diffusion bonding in the stacking direction. Note that the floor plate 3 and the ceiling plate 4 are not limited to being made of multiple metal plates, and may each be formed from a single metal plate. Furthermore, after diffusion bonding, the dashed lines aligned in the stacking direction (dashed lines indicating the boundaries between the multiple protective plates and the heat transfer plates) may disappear.

Four spaces 260, 270, 280, and 290 extending in the stacking direction are formed inside the heat transfer section 2 of the laminate 1. If the stacking direction is defined as the Z-axis direction, the direction from space 260 to space 280 as the X-axis direction, and the direction from space 270 to space 290 as the Y-axis direction, then of the four spaces 260, 270, 280, and 290, one of two spaces aligned in the Y-axis direction, space 270, is connected to hole 2hb, and the other space 290 is connected to hole 2hd. Furthermore, of the two spaces 260, 280 aligned in the X-axis direction, one space 260 is connected to hole 2ha, and the other space 280 is connected to hole 2hc.

Figure 2 is a schematic plan view of the laminate according to this embodiment. Figure 2 shows the laminate 1 as viewed from the main surface 1u in the Z-axis direction.

The ceiling board 4 has a main body plate portion 400, four annular portions 412, 422, 432, and 442, a rib portion 413 connecting the main body plate portion 400 and the annular portion 412, a rib portion 423 connecting the main body plate portion 400 and the annular portion 422, a rib portion 433 connecting the main body plate portion 400 and the annular portion 432, and a rib portion 443 connecting the main body plate portion 400 and the annular portion 442. A slit portion 414 is provided between the main body plate portion 400 and the annular portion 412. A slit portion 424 is provided between the main body plate portion 400 and the annular portion 422. A slit portion 434 is provided between the main body plate portion 400 and the annular portion 432. A slit portion 444 is provided between the main body plate portion 400 and the annular portion 442.

The main body plate portion 400 covers at least the heat exchange areas (described below) of heat transfer plates 21A and 21B in the stacking direction. The annular portion 412 is separated from the main body plate portion 400 by a slit portion 414. The annular portion 422 is separated from the main body plate portion 400 by a slit portion 424. The annular portion 432 is separated from the main body plate portion 400 by a slit portion 434. The annular portion 442 is separated from the main body plate portion 400 by a slit portion 444.

Annular portion 412 has hole 2ha. Hole 2ha communicates with a flow path provided in heat transfer plate 21B via space 260. Annular portion 422 has hole 2hb. Hole 2hb communicates with a flow path provided in heat transfer plate 21A via space 270. Annular portion 432 has hole 2hc. Hole 2hc communicates with a flow path provided in heat transfer plate 21B via space 280. Annular portion 442 has hole 2hd. Hole 2hd communicates with a flow path provided in heat transfer plate 21A via space 290.

The laminate 1 shown in Figures 1 and 2 is applied, for example, to a heat exchanger 10 (stacked microchannel heat exchanger) shown in Figure 3. Figure 3 is a schematic perspective view showing a heat exchanger according to this embodiment. In the heat exchanger 10, external pipes 101, 102, 103, and 104 are joined to the main surface 1u of the laminate 1 by, for example, brazing. Each of the external pipes 101, 102, 103, and 104 may be applied to a refrigerant pipe that is directly connected to a refrigerant circuit, or may be applied as part of a joint (piping portion) for connecting a refrigerant pipe connected to the refrigerant circuit to a heat exchanger.

For example, external pipe 101 is inserted into hole 2ha and joined to hole 2ha by brazing. External pipe 102 is inserted into hole 2hb and joined to hole 2hb by brazing. External pipe 103 is inserted into hole 2hc and joined to hole 2hc by brazing. External pipe 104 is inserted into hole 2hd and joined to hole 2hd by brazing.

For example, when a high-temperature fluid flows into the stack 1 from the external pipe 102, the high-temperature fluid passes through the heat transfer section 2 via the space 270 and then flows out of the external pipe 104 via the space 290. On the other hand, when a low-temperature fluid flows into the stack 1 from the external pipe 103, the low-temperature fluid passes through the heat transfer section 2 via the space 280 and then flows out of the external pipe 101 via the space 260.

Figure 4 shows a schematic cross section of the state in which external piping is joined to the hole. Figure 4 is a schematic cross section of the laminate cut in the Z-axis direction along the dashed line L1 in Figure 3. Of the hole portions 2ha, 2hb, 2hc, and 2hd, Figure 4 shows hole portion 2ha and the structure surrounding hole portion 2ha. The cross-sectional structure shown in Figure 4 also applies to hole portions 2hb, 2hc, and 2hd and the respective surrounding structures of hole portions 2hb, 2hc, and 2hd.

As shown in FIG. 4, the external pipe 101 is inserted into the hole 2ha. In the heat exchanger 10, a bonding material 405, which is a brazing material such as silver brazing, is provided between the external pipe 101 and the annular portion 412. By inserting the external pipe 101 into the hole 2ha, the external pipe 101 is connected to the space 260.

As shown in Figures 4 and 2, the annular portion 412 has a predetermined length (height) in the Z-axis direction and is, for example, cylindrical. The shape of the annular portion 412 also applies to each of the annular portions 422, 432, and 442. The rib portion 413 has a predetermined length (height) in the Z-axis direction and is columnar (rectangular bar-like). The shape of the rib portion 413 also applies to each of the rib portions 423, 433, and 443. The slit portion 414 is formed by connecting slit portions 414a (Figure 6(a)), described below, in the stacking direction. The slit portion 414 has a predetermined length (height) in the Z-axis direction and is a space formed along the outer periphery of the annular portion 412. The shape of the slit portion 414 also applies to each of the slit portions 424, 434, and 444.

In addition, hole 2ha is provided with a locking portion 205 that stops the external pipe 101 from being inserted into hole 2ha when the external pipe 101 is inserted into hole 2ha. For example, hole 2ha has hole 201a (first hole) formed in protective plate 41 and hole 202a (second hole) formed in protective plate 42. Here, the inner diameter R1 of hole 201a is smaller than the inner diameter R2 of hole 202a and the outer diameter R3 of the external pipe 101. This creates a step between protective plate 41 and protective plate 42 stacked on protective plate 41. The portion of protective plate 41 that protrudes from protective plate 42 toward the center of hole 2ha functions as a locking portion that stops the external pipe 101 from being inserted into hole 2ha. Note that such a protruding portion is not limited to the protective plate portion 41, but may also be provided, for example, on any of the protective plate portions 42 above the protective plate portion 41.

Figures 5(a) and (b) are schematic perspective views of heat transfer plates included in the heat transfer section of the laminate. Figure 5(a) shows heat transfer plate 21A included in heat transfer section 2, and Figure 5(b) shows heat transfer plate 21B included in heat transfer section 2. Figure 5(c) is a schematic perspective view of a protective plate portion that forms the floor plate of the laminate.

The heat transfer plate 21A shown in FIG. 5(a) is formed from a metal plate having a predetermined thickness and a rectangular planar shape. The heat transfer plate 21A has through holes 26, 27, 28, and 29 formed along the inside of each of its four sides. The heat transfer plate 21A also includes a heat exchange area (first heat exchange area). For example, the heat transfer plate 21A has a groove 255, multiple grooves 250, and groove 256 that form a flow path for a high-temperature fluid formed on the main surface of the heat transfer plate 21A that faces the main surface 1u of the laminate 1. Each of the multiple grooves 250 is connected to groove 255 and groove 256. Grooves 255, 250, and 256 are formed on the main surface of the heat transfer plate 21A by, for example, half-etching.

Multiple grooves 250 are formed along the X-axis direction. Grooves 255 and 256 are formed along the Y-axis direction. One end of groove 255 communicates with through-hole 27. One end of groove 256 communicates with through-hole 29. In other words, between the through-holes 27 and 29 provided at both ends in the Y-axis direction, multiple grooves 250, 255, and 256 are formed, connecting through-hole 27 and through-hole 29. Groove 255, multiple grooves 250, and groove 256 form the heat exchange area of heat transfer plate 21A.

The heat transfer plate 21B shown in FIG. 5(b) is formed from a rectangular metal plate having a predetermined thickness and the same planar shape as the heat transfer plate 21A. The heat transfer plate 21B has through holes 26, 27, 28, and 29 formed along the inside of each of its four sides. The heat transfer plate 21B also includes a heat exchange area (second heat exchange area). For example, the heat transfer plate 21B has grooves 251 formed on the main surface on the side of the main surface 1u of the laminate 1, which form the heat exchange area and a flow path for the low-temperature fluid. The grooves 251 are formed on the main surface of the heat transfer plate 21B by, for example, half-etching. The multiple grooves 251 are formed along the X-axis direction. One end of the groove 251 communicates with the through hole 26, and the other end communicates with the through hole 28.

That is, between the through holes 26 and 28 provided at both ends in the X-axis direction, multiple grooves 251 are formed that connect the through holes 26 and 28. The multiple grooves 251 form the heat exchange area of the heat transfer plate 21B.

In the heat transfer section 2 of the laminate 1, heat transfer plates 21A and 21B are joined alternately in the stacking direction, so that through holes 26 in heat transfer plates 21A and through holes 26 in heat transfer plates 21B are alternately connected in the stacking direction. This forms space 260. Through holes 27 in heat transfer plates 21A and through holes 27 in heat transfer plates 21B are alternately connected in the stacking direction. This forms space 270. Through holes 28 in heat transfer plates 21A and through holes 28 in heat transfer plates 21B are alternately connected in the stacking direction. This forms space 280. Through holes 29 in heat transfer plates 21A and through holes 29 in heat transfer plates 21B are alternately connected in the stacking direction. This forms space 290.

The protective plate portion 31 shown in Figure 5 (c) forms the floor plate 3. The protective plate portion 31 is formed from a rectangular metal plate having a predetermined thickness and a planar shape identical to that of the heat transfer plate 21A. The thickness of the protective plate portion 31 may or may not be the same as that of the heat transfer plates 21A and 21B.

Figures 6(a) and (b) are schematic perspective views of the protective plate portion that forms the ceiling plate of the laminate. Figure 6(a) shows one plate member 420 of the multiple plate members 420 that form the protective plate portion 42 of the ceiling plate 4. The plate member 420 is formed from a rectangular metal plate with a predetermined thickness and the same planar shape as the heat transfer plate 21A. The thickness of the plate member 420 may or may not be the same as the thickness of the heat transfer plates 21A and 21B.

The plate-shaped member 420 includes a main body plate portion 400b, four annular members 412a, 422b, 432c, and 442d, a plate-shaped rib member 413a connecting the main body plate portion 400b and the annular member 412a, a plate-shaped rib member 423b connecting the main body plate portion 400b and the annular member 422b, a plate-shaped rib member 433c connecting the main body plate portion 400b and the annular member 432c, and a plate-shaped rib member 443d connecting the main body plate portion 400b and the annular member 442d. In the plate-shaped member 420, the main body plate portion 400b covers at least the heat exchange area of the heat transfer plate 21A and the heat exchange area of the heat transfer plate 21B in the stacking direction. In this embodiment, the main body plate portion 400b is the first main body plate portion, each of the four annular members 412a, 422b, 432c, and 442d is the first annular member, and each of the rib members 413a, 423b, 433c, and 443d is the first rib member.

A slit portion 414a is provided between the main body plate portion 400b and the annular member 412a. The annular member 412a is separated from the main body plate portion 400b by the slit portion 414a. A slit portion 424b is provided between the main body plate portion 400b and the annular member 422b. The annular member 422b is separated from the main body plate portion 400b by the slit portion 424b. A slit portion 434c is provided between the main body plate portion 400b and the annular member 432c. The annular member 432c is separated from the main body plate portion 400b by the slit portion 434c. A slit portion 444d is provided between the main body plate portion 400b and the annular member 442d. The annular member 442d is separated from the main body plate portion 400b by the slit portion 444d. The annular member 412a has a hole portion 202a. The annular member 422b has a hole 202b. The annular member 432c has a hole 202c. The annular member 442d has a hole 202d.

Figure 6(b) shows the protective plate portion 41 of the ceiling plate 4. The protective plate portion 41 is formed from a rectangular metal plate having a predetermined thickness and the same planar shape as the heat transfer plate 21A. The thickness of the protective plate portion 41 may or may not be the same as the thickness of the heat transfer plates 21A and 21B. The protective plate portion 41 has a main plate portion 400a and four hole portions 201a, 201b, 201c, and 201d. The main plate portion 400a covers at least the heat exchange area of the heat transfer plate 21A and the heat exchange area of the heat transfer plate 21B in the stacking direction. The protective plate portion 41 does not have an annular portion or a slit. Furthermore, the inner diameter of hole 201a is smaller than the inner diameter of hole 202a, the inner diameter of hole 201b is smaller than the inner diameter of hole 202b, the inner diameter of hole 201c is smaller than the inner diameter of hole 202c, and the inner diameter of hole 201d is smaller than the inner diameter of hole 202d.

Multiple protective plate sections 31 are stacked in the stacking direction, and heat transfer plates 21A and 21B are stacked alternately on top of these. Furthermore, protective plate sections 41 and multiple plate-like members 420 are stacked on top of these, and each is bonded by diffusion bonding to form the stack body 1 shown in Figure 1.

In the ceiling panel 4, the annular ring members 412a formed on each of the multiple plate-like members 420 are joined in the stacking direction to form the cylindrical annular portion 412, the annular ring members 422b formed on each of the multiple plate-like members 420 are joined in the stacking direction to form the cylindrical annular portion 422, the annular ring members 432c formed on each of the multiple plate-like members 420 are joined in the stacking direction to form the cylindrical annular portion 432, and the annular ring members 442d formed on each of the multiple plate-like members 420 are joined in the stacking direction to form the cylindrical annular portion 442.

In addition, in the ceiling board 4, the rib members 413a formed on each of the multiple plate-shaped members 420 are joined in the stacking direction to form the rib portion 413, the rib members 423b formed on each of the multiple plate-shaped members 420 are joined in the stacking direction to form the rib portion 423, the rib members 433c formed on each of the multiple plate-shaped members 420 are joined in the stacking direction to form the rib portion 433, and the rib members 443d formed on each of the multiple plate-shaped members 420 are joined in the stacking direction to form the rib portion 443.

In addition, in the ceiling board 4, the slit portions 414a formed on each of the multiple plate-like members 420 are joined in the stacking direction to form the slit portion 414, the slit portions 424b formed on each of the multiple plate-like members 420 are joined in the stacking direction to form the slit portion 424, the slit portions 434c formed on each of the multiple plate-like members 420 are joined in the stacking direction to form the slit portion 434, and the slit portions 444d formed on each of the multiple plate-like members 420 are joined in the stacking direction to form the slit portion 444.

The operation of this embodiment will now be described. Figure 7(a) is a schematic diagram illustrating the operation of a comparative example, and Figure 7(b) is a schematic diagram illustrating the operation of this embodiment. Figures 7(a) and (b) show the state when the external pipe 101 is inserted into the hole 2ha, and the hole 2ha and the external pipe 101 are joined with the joining material 405 by flame brazing (torch brazing, hereinafter simply referred to as brazing) using a burner flame as the heat source. The operation when the external pipe 101 is brazed to the hole 2ha in this embodiment also applies to the operation when the external pipe 102 is brazed to the hole 2hb, the operation when the external pipe 103 is brazed to the hole 2hc, and the operation when the external pipe 104 is brazed to the hole 2hd.

In the comparative example shown in Figure 7(a), the annular portion 412 and the slit portion 414 are not provided. Therefore, when the external pipe 101 and the laminate 1 are heated with the burner 500 during brazing, the temperature of the external pipe 101 quickly reaches the melting temperature of the joining material 405, but the temperature of the laminate 1 may not quickly reach the melting temperature of the joining material 405. This is because the heat capacity of the laminate 1, which is the base material of the external pipe 101, is greater than the heat capacity of the external pipe 101.

If brazing is attempted in this state, the bonding material 405 may not flow sufficiently between the external pipe 101 and the hole 2ha, which could result in a poor bond between the external pipe 101 and the laminate 1. One way to address this is to continue heating the laminate 1 until the temperature of the laminate 1 reaches the melting temperature of the bonding material 405. However, this method not only unnecessarily lengthens the heating time, but also has the risk of deformation of the external pipe 101 or the laminate 1 due to overheating. There is also a risk of the bonding material 405 oxidizing or flowing too much, resulting in poor brazing.

In contrast, in the present embodiment shown in FIG. 7(b), an annular portion 412 is formed with a hole 2ha. Furthermore, the annular portion 412 is separated from the main body plate portion 400 by a slit portion 414. Therefore, when the external pipe 101 and the annular portion 412 are heated with the burner 500, the temperature of the external pipe 101 reaches the melting temperature of the bonding material 405 more quickly than when the slit portion 414 is not provided, and the temperature of the annular portion 412 also reaches the melting temperature of the bonding material 405 more quickly. This is because the annular portion 412 is separated from the main body plate portion 400 by the slit portion 414, and the slit portion 414 prevents the heat used to heat the external pipe 101 and the annular portion 412 from escaping to the main body plate portion 400, which has a larger heat capacity.

Therefore, when the external pipe 101 and the annular portion 412 are heated with the burner 500, both the external pipe 101 and the annular portion 412 reach the melting temperature of the joining material 405 more quickly than if the slit portion 414 were not provided. As a result, the joining material 405 flows sufficiently between the external pipe 101 and the hole 2ha. This more reliably joins the external pipe 101 and the annular portion 412 with the joining material 405. Furthermore, because the temperature of the annular portion 412 quickly reaches the melting temperature of the joining material 405, the heating time is not unnecessarily extended. As a result, deformation of the external pipe 101 or the laminate 1 due to overheating is less likely to occur. Furthermore, oxidation of the joining material 405 and poor brazing due to excessive flow of the joining material 405 are less likely to occur.

Furthermore, according to this embodiment, there is no need to previously join the external piping 101 to the ceiling plate 4 before forming the stack 1 by diffusion bonding. This allows the metal plates stacked in the stacking direction to be reliably pressed from above and below using a pressure jig, allowing the stack 1 to be stably formed using diffusion bonding.

When brazing the external pipe 101 to the hole 2ha, flux may be used in addition to the bonding material 405 to ensure a good bond. However, if flux remains on the joint after the external pipe 101 is brazed to the hole 2ha, there is a risk that the flux may corrode the part where the flux is attached. For this reason, it is desirable to remove any remaining flux from the laminate 1 after brazing.

For example, when flux is applied to the external pipe 101 or the annular portion 412, the flux may flow into the slit portion 414 near the external pipe 101. If the flux is left in the slit portion 414, the inner wall of the slit portion 414 may be corroded by the flux. For this reason, it is desirable to remove any remaining flux from the slit portion 414. However, if the flux penetrates deep into the slit portion 414, it will be difficult to remove the flux from the slit portion 414 even if cleaning or air blowing is attempted.

In contrast, in this embodiment, an open hole is provided on the side of the ceiling plate 4 of the laminate 1, connecting the slit portion 414 to the outside of the laminate 1. This open hole makes it possible to remove flux remaining in the slit portion 414.

Figure 8 is a schematic perspective view showing an example in which an open hole is provided on the side of the ceiling plate, connecting the slit portion with the outside of the stack. Figure 8 shows a schematic diagram of the case in which the ceiling plate 4 is separated from the heat transfer portion 2 in the stacking direction. Of the annular portions 412-442, Figure 8 shows annular portion 412 and the side surface 4w near annular portion 412, but this structure also applies to annular portions 422, 432, and 442 and the side surfaces near each of annular portions 422, 432, and 442. Figure 9 is a schematic cross-sectional view of the stack cut in the Z-axis direction along the dashed dotted line L1 in Figure 8. In addition to the stack 1, Figure 9 also shows the external piping 101.

As shown in Figure 8, the ceiling board 4 has a main surface 4d (first main surface) joined to the heat transfer plate, and a main surface 4u opposite the main surface 4d, which serves as the main surface 1u of the laminate 1. The ceiling board 4 also has a side surface 4w that is part of the side surface 1w and is continuous with the main surface 4d and the main surface 4u.

The ceiling plate 4 includes, in the stacking direction, a protective plate portion 41 stacked on the heat transfer plate 21B and a protective plate portion 42 stacked on the protective plate portion 41. The protective plate portion 42 is formed by a plurality of plate-shaped members 420.

At least one open hole 4h is provided in the protective plate portion 42. The open hole 4h is formed by a pair of plate-shaped members 420 that are diffusion-bonded in the stacking direction. Each open hole 4h is open on the side surface 4w and communicates with the slit portion 414.

Figures 10(a) and (b) show a plate-shaped member 420 selected from the multiple plate-shaped members 420 shown in Figures 8 and 9. Here, Figure 10(a) shows a schematic perspective view of the plate-shaped member 420, and Figure 10(b) shows a schematic cross-sectional view of the plate-shaped member cut in the Z-axis direction along the dashed dotted line L1 in Figure 10(a).

For example, in the plate-shaped member 420, the thickness d2 of the rib member 413a is formed thinner than the thickness d1 of the main plate portion 400b. For example, the thickness d2 is half the thickness d1. Furthermore, the plate-shaped member 420 is formed with a discharge groove 420t that communicates with the slit portion 414a. This slit portion 414a is connected in the stacking direction to form the slit portion 414 shown in Figures 8 and 9, and therefore the discharge groove 420t communicates with the slit portion 414.

The discharge groove 420t is formed by thinning a portion of the main plate portion 400b. The discharge groove 420t is formed on the side of the plate-shaped member 420, on the main surface 1u side, which is the upper surface of the laminate 1. The thinned portion of the main plate portion 400b becomes the bottom 420p of the discharge groove 420t, and the bottom 420p is connected to the rib member 413a. The thickness d3 of the bottom 420p of the discharge groove 420t is formed to be the same as or approximately the same as the thickness d2 of the rib member 413a. The rib member 413a and the bottom 420p are formed, for example, by half-etching.

The discharge groove 420t is provided in at least one of the multiple plate-like members 420 stacked in the stacking direction. After diffusion bonding, the discharge groove 420t is covered by the plate-like member 420 directly above it, forming an open hole 4h. In other words, at least one open hole 4h is formed in the side surface 42w of the protective plate portion 42. Note that while Figures 8 and 9 show an example in which a discharge groove 420t is provided in each of the multiple plate-like members 420, this example is not limiting.

Figure 11 is a schematic diagram showing the function of a laminate with open holes. Figure 11 shows one of the plate-shaped members 420 included in the protective plate portion 42 of the laminate 1 after diffusion bonding.

For example, when external piping 101 is brazed to hole 2ha with joining material 405, flux is also used. After brazing, any flux that has entered slit 414 is removed by washing with warm water or by blowing air through slit 414. Any flux remaining inside slit 414 flows out of laminate 1 through open hole 4h connected to slit 414 (arrow). As a result, flux does not remain in slit 414 in laminate 1, reliably avoiding corrosion caused by flux.

Furthermore, in any of the multiple plate-like members 420, the discharge groove 420t is not limited to being formed on the main surface 1u side, which is the upper surface of the laminate 1, but may also be formed on the main surface 1d side, which is the lower surface of the laminate 1.

Figure 12(a) is a schematic perspective view showing an example in which a discharge groove is formed on the main surface of a plate-shaped member that will become the lower surface of the laminate. Figure 12(b) is a schematic perspective view of the plate-shaped member 420 shown in Figure 12(a) cut along dashed lines L2 and L3, with a portion of the plate-shaped member 420 (the portion indicated by arrow A) removed.

As shown in FIG. 12(a), the discharge groove 420t is formed in the protective plate 41 and the plate-shaped member 420 joined to the protective plate 41. Here, in the plate-shaped member 420, the discharge groove 420t is formed on the protective plate 41 side. Here, in the embodiment shown in FIGS. 8 to 11, the bottom 420p illustrated in FIG. 10 is located between the protective plate 41 and the open hole 4h above the protective plate 41. Therefore, a step is formed between the protective plate 41 and the discharge groove 420t. In contrast, with the structure shown in FIG. 12(a), the protective plate 41 and the rib member 413a of the plate-shaped member 420 do not form a step as in the embodiment shown in FIGS. 8 to 11. Therefore, the flux does not overcome the step and is more smoothly discharged to the outside of the laminate 1 through the open hole 4h (arrow), as shown in FIG. 12(b).

In addition, the discharge grooves 420t provided on the plate-like members 420 may be arranged opposite each other in the stacking direction. For example, a plate-like member 420 having a discharge groove 420t formed on the main surface 1u, which is the upper surface of the laminate 1, and a plate-like member 420 having a discharge groove 420t formed on the main surface 1d, which is the lower surface of the laminate 1, are joined together in the stacking direction.

Figure 13 is a schematic perspective view showing a ceiling board in which a plate-shaped member with a discharge groove formed on the upper surface of the stack and a plate-shaped member with a discharge groove formed on the lower surface of the stack are joined in the stacking direction.

As shown in FIG. 13, of the multiple plate-shaped members 420, at least two plate-shaped members 420 that are joined to each other in the stacking direction are provided with discharge grooves 420t. The discharge grooves 420t provided in these two plate-shaped members 420 face each other in the stacking direction. As a result, the height of the open hole 4h in the stacking direction is twice as high as when the discharge grooves 420t are not facing each other.

This reduces the flow resistance of the open holes 4h to the flux, allowing the flux to be more smoothly released to the outside of the laminate 1 through the open holes 4h.

Furthermore, multiple rib portions (for example, four) may be provided around the annular portion. For example, Figure 14 is a schematic plan view showing an example in which multiple rib portions 413 are provided around the annular portion 412. The planar structure shown in Figure 14 also applies to each of the annular portions 422 to 442.

With this structure, the annular portion 412 is connected to the main body plate portion 400 by multiple rib portions 413. This allows the annular portion 412 to be more firmly supported by the main body plate portion 400. Furthermore, the rib members 413a that form each of the multiple rib portions 413 are thinned using a half-etching technique. This creates gaps between adjacent rib members 413a in the stacking direction. This allows flux to pass through these gaps and then be released to the outside of the laminate 1 through the open holes 4h.

The above describes an embodiment of the present invention, but the present invention is not limited to the above embodiment and various modifications can be made. The structure for joining the external pipes 101-104 to the laminate 1 has been described only in terms of joining the external pipes 101-104 to the ceiling panel 4. Any of the external pipes 101-104 may be joined to the laminate 1 from the floor panel 3 side, not just the ceiling panel 4. For example, any of the following sets of annular portion 412, rib portion 413, and slit portion 414; annular portion 422, rib portion 423, and slit portion 424; annular portion 432, rib portion 433, and slit portion 434; and annular portion 442, rib portion 443, and slit portion 444 may be provided on the floor panel 3. Furthermore, the rib member 413a and the discharge groove 420t do not have to be in the same position, as long as the annular portion 412a and the main body plate portion 400b are connected and the slit portion 414a and the discharge groove 420t are in communication. Furthermore, the external pipes 101-104 and the laminate 1 may be made of different materials; for example, the external pipes 101-104 may be copper pipes and the laminate 1 may be a stainless steel laminate. Each embodiment is not limited to being an independent form, and can be combined as far as technically possible.

1... Laminated body 1u, 1d, 4u, 4d... Main surface 1w, 4w... Side surface 2... Heat transfer part 2ha, 2hb, 2hc, 2hd... Hole part 3... Floor plate 4... Ceiling plate 4h... Open hole 10... Heat exchanger 21B, 21A... Heat exchanger plate 26, 27, 28, 29... Through hole 31, 41, 42... Protective plate part 42w... Side surface 101, 102, 103, 104... External piping 201a, 201b, 201c, 201d, 202a, 202b, 202c, 202d... Hole 205... Locking part 250, 251, 255, 256... Groove 260, 270, 280, 290... Space 400, 400a, 400b...Body plate part 405... Bonding material 412, 422, 432, 442... Annular portion 412a, 422b, 432c, 442d... Annular member 413, 423, 433, 443... Rib portion 413a, 423b, 433c, 443d... Rib member 414, 424, 434, 444... Slit portion,
414a, 424b, 434c, 444d...slit portion 420...plate-shaped member 420p...bottom portion 420t...discharge groove 500...burner

Claims (10)

A protective plate,
a heat transfer plate including a heat exchange area in which a flow path is formed;
A laminate in which the protective plate and the heat transfer plate are bonded by diffusion bonding,
The protective plate is
a first main surface joined to the heat transfer plate, a second main surface opposite to the first main surface, and a side surface connected to the first main surface and the second main surface;
a main body plate portion that covers at least the heat exchange area in a stacking direction in which the protection plate and the heat transfer plate are stacked;
an annular portion provided on the main body plate portion with a slit portion therebetween;
a rib portion connecting the annular portion and the main body plate portion,
the annular portion has a hole, the hole communicates with the flow path;
The protective plate has an open hole on the side surface that connects the slit portion to the outside of the laminate.
Laminate. 2. The laminate according to claim 1,
The protective plate is
a first protective plate portion stacked on the heat transfer plate in the stacking direction;
a second protective plate portion stacked on the first protective plate portion in the stacking direction,
the second protective plate portion is provided with the open hole. 3. The laminate according to claim 2 ,
The hole of the protective plate is provided with a locking portion that stops the insertion of the external pipe halfway through the hole when the external pipe is inserted into the hole. The laminate according to claim 2 or 3 ,
the hole portion has a first hole portion formed in the first protective plate portion and a second hole portion formed in the second protective plate portion, and the inner diameter of the first hole portion is smaller than the inner diameter of the second hole portion. The laminate according to any one of claims 2 to 4 ,
The second protective plate portion is formed of a plurality of plate-shaped members,
a groove portion communicating with the slit portion and forming the open hole is provided in at least one of the plurality of plate-like members. 6. The laminate according to claim 5 ,
Each of the plurality of plate-like members is
a first main body plate portion covering at least the heat exchange area in the stacking direction;
a first annular member provided with a slit portion separated from the first main body plate portion;
a first rib member that connects the first annular portion and the first main body plate portion and forms the rib portion by joining the plurality of plate-like members in the stacking direction ,
The thickness of the first rib member is thinner than the thickness of the first main body plate portion,
the groove portion is formed by thinning a portion of the main body plate portion,
The first rib member and the portion are connected to each other. 7. The laminate according to claim 6 ,
a laminate including the first protective plate portion, and the groove portion being formed on a side of the first protective plate portion of one of the plurality of plate-like members that is joined to the first protective plate portion. The laminate according to claim 6 or 7 ,
The groove portion is provided in at least two of the plurality of plate-shaped members that are joined to each other in the stacking direction,
the grooves provided in the at least two plate-like members face each other in the stacking direction. The laminate according to any one of claims 1 to 8 ,
A laminate having a plurality of the rib portions. A laminate according to any one of claims 1 to 9 ;
an external pipe inserted into the hole;
a bonding material provided between the external piping and the annular portion.