Heat exchanger

Abstract

[Problem] To provide a heat exchanger that makes it possible to determine, using a more rapid method, whether fluid outlet / inlet ports and fluid flow passages, which should be separated by isolating portions formed in metal plates stacked in a stacked-type heat exchanger, are in communication with one another. [Solution] A plurality of first metal plates and a plurality of second metal plates are stacked alternately. Each of the plurality of first metal plates is provided with: a first flow path through which a first fluid flows; a first outlet / inlet port and a second outlet / inlet port; a first through-hole and a second through-hole that allow a second fluid to pass through; a first isolating portion that separates the first flow path and the first through-hole; and a second isolating portion that separates the first flow path and the second through-hole. Each of the plurality of second metal plates is provided with: a second flow path through which the second fluid flows; a third outlet / inlet port and a fourth outlet / inlet port; a third through-hole and a fourth through-hole that allow the first fluid to pass through; a third isolating portion that separates the second flow path and the third through-hole; and a fourth isolating portion that separates the second flow path and the fourth through-hole. A groove is formed in at least one of the first isolating portion, the second isolating portion, the third isolating portion, and the fourth isolating portion.

Description

heat exchanger

[0001] The present invention relates to a stacked heat exchanger.

[0002] There is a heat exchanger in which flow channels are formed in multiple metal plates, which are stacked and bonded by diffusion bonding (see, for example, Patent Document 1). The metal plates have a flow channel for high-temperature fluid on one side, a flow channel for low-temperature fluid on the other side, and an inlet and outlet for the high-temperature fluid and an inlet and outlet for the low-temperature fluid that penetrate the metal plates.

[0003] The metal plate further has a separator formed between the low-temperature fluid inlet and the high-temperature fluid flow path, a separator formed between the low-temperature fluid outlet and the high-temperature fluid flow path, a separator formed between the high-temperature fluid inlet and the low-temperature fluid flow path, and a separator formed between the high-temperature fluid outlet and the low-temperature fluid flow path, which prevent the low-temperature fluid from entering the high-temperature fluid flow path or prevent the high-temperature fluid from entering the low-temperature fluid flow path.

[0004] If any of the separators were to be scratched for some reason, and the inlet or outlet for the low-temperature fluid were to become connected to the flow path for the high-temperature fluid, or the inlet or outlet for the high-temperature fluid and the flow path for the low-temperature fluid, the flow paths for the high-temperature fluid would become connected inside the heat exchanger, causing the high-temperature and low-temperature fluids to mix, making the heat exchanger unusable. To eliminate such heat exchangers, leak tests are conducted on the above-mentioned heat exchangers to check the bonding condition of the metal plates.

[0005] For example, one of the two inlets and outlets (outlet and inlet) for the low-temperature fluid is blocked, the other is connected to a vacuum pump and a leak detector, and one of the two inlets and outlets (outlet and inlet) for the high-temperature fluid is blocked. After reducing the pressure inside the low-temperature fluid flow path using a vacuum pump, a test gas (e.g., He) is injected into the other of the two inlets and outlets (outlet and inlet) for the high-temperature fluid, and the presence or absence of a leak is detected using a leak detector. Furthermore, the blocked side and the test gas injection side of one of the inlets and outlets for the high-temperature fluid are switched, and the presence or absence of a leak is detected in the same way. If a leak is detected, the test gas will leak into the low-temperature fluid flow path, and this can be detected by the leak detector, indicating the presence of a leak between the low-temperature fluid flow path and the high-temperature fluid flow path. Alternatively, one of the two inlets and outlets (outlet and inlet) for the high-temperature fluid is blocked, the other is connected to a vacuum pump and a leak detector, and one of the two inlets and outlets (outlet and inlet) for the low-temperature fluid is blocked. After reducing the pressure inside the high-temperature fluid flow path with a vacuum pump, a test gas (e.g., He) is injected into one of the two low-temperature fluid inlets (outlet and inlet), and the presence or absence of a leak is detected with a leak detector. The presence or absence of a leak is then similarly detected for the other low-temperature fluid outlet. If a leak is found, the test gas will leak into the high-temperature fluid flow path, and this will be detected by the leak detector, indicating that there is a leak between the high-temperature fluid flow path and the low-temperature fluid flow path.

[0006] Japanese Patent Application Laid-Open No. 2018-096581

[0007] However, in such a leak test method, the distance between the point where the test gas is injected and the point where the test gas is detected is inevitably long.

[0008] This lengthens the detection time from when the test gas is injected until the test gas is detected. As a result, the leak detection response slows down, and there is a higher possibility that a leak will not be detected even though it is actually present, resulting in a latent defect occurring in which a product that was deemed good turns out to be defective at the stage of use. Furthermore, the longer detection time requires a large amount of test gas, which increases the inspection cost. This problem is particularly noticeable in stacked heat exchangers (stacked microchannel heat exchangers) that have many fine flow paths formed inside them.

[0009] In view of the above circumstances, an object of the present invention is to provide a heat exchanger that enables a quicker determination of whether a fluid inlet / outlet and a fluid flow path, which should be separated by an isolation portion formed on the stacked metal plates, are connected to each other in a stacked heat exchanger.

[0010] To achieve the above object, one aspect of the present invention provides a heat exchanger in which a plurality of metal plates are stacked and joined together. The plurality of metal plates includes a plurality of first metal plates and a plurality of second metal plates, and the first metal plates and the second metal plates are alternately stacked. Each of the first metal plates is provided with a first flow path through which a first fluid flows, a first inlet / outlet and a second inlet / outlet connected to the first flow path, a first through hole and a second through hole through which a second fluid passes, a first isolation portion separating the first flow path from the first through hole, and a second isolation portion separating the first flow path from the second through hole. Each of the plurality of second metal plates is provided with a second flow path through which the second fluid flows, a third inlet and a fourth inlet connected to the second flow path, a third through hole and a fourth through hole through which the first fluid passes, a third isolation portion separating the second flow path from the third through hole, and a fourth isolation portion separating the second flow path from the fourth through hole. In a stacked block main body in which the plurality of first metal plates and the plurality of second metal plates are alternately stacked, at least one of the first isolation portion, the second isolation portion, the third isolation portion, and the fourth isolation portion has a groove whose one end is open to the outside of the stacked block main body.

[0011] With such a heat exchanger, it is possible to more quickly determine whether the fluid inlet and outlet ports are connected to the fluid flow path, as they are separated by a separator formed in the laminated metal plates.

[0012] In the heat exchanger, the other end of the groove may be open to the outside of the laminated block body.

[0013] With such a heat exchanger, it is possible to more quickly determine whether the fluid inlet and outlet ports are connected to the fluid flow path, as they are separated by a separator formed in the laminated metal plates.

[0014] In the above heat exchanger, the groove may be formed in at least one of the following: between the first isolation portion and the second metal plate in contact with the first isolation portion; between the second isolation portion and the second metal plate in contact with the second isolation portion; between the third isolation portion and the first metal plate in contact with the third isolation portion; and between the fourth isolation portion and the first metal plate in contact with the fourth isolation portion.

[0015] With such a heat exchanger, it is possible to more quickly determine whether the fluid inlet and outlet ports are connected to the fluid flow path, as they are separated by a separator formed in the laminated metal plates.

[0016] As described above, the present invention provides a heat exchanger that makes it possible to more quickly determine whether a fluid inlet / outlet and a fluid flow path that should be separated by an isolation section formed on the stacked metal plates are connected in a stacked heat exchanger.

[0017] FIG. 1 is a schematic perspective view showing a heat exchanger of the present embodiment. FIG. 2 is a schematic perspective view showing metal plates forming a laminated block body before diffusion bonding. FIG. 3(a) is a schematic perspective view showing metal plates forming a ceiling plate before diffusion bonding, and FIG. 3(b) is a schematic perspective view showing metal plates forming a floor plate before diffusion bonding. FIG. 4 is a schematic perspective view showing a part of a laminated block body. FIG. 5 is a schematic perspective view showing a part of a laminated block body according to a comparative example. FIG. 6 is a diagram showing an outline of a leak test using He gas in a comparative example. FIG. 7 is a schematic perspective view showing a state in which a scratch is formed in a second isolation portion of a metal plate of the present embodiment. FIG. 8 is a diagram showing an example of an outline of a leak test using He gas in the present embodiment. FIG. 9 is a diagram conceptually showing the relationship between the time after injecting a test gas into a heat exchanger and the amount of leakage of the test gas.

[0018] Hereinafter, embodiments of the present invention will be described with reference to the drawings. X, Y, and Z axis coordinates may be used in each drawing. In addition, the same reference numerals may be used to designate identical components or components having the same functions, and after describing the components, the description may be omitted as appropriate.

[0019] (Heat Exchanger) Fig. 1 is a schematic perspective view showing a heat exchanger of this embodiment. The heat exchanger 1 shown in Fig. 1 is a stacked heat exchanger (stacked microchannel heat exchanger) in which multiple metal plates are stacked and joined. The heat exchanger 1 includes a stacked block body 2, a ceiling panel 3, and a floor panel 4.

[0020] The laminated block body 2 includes a plurality of metal plates 21 (first metal plates) and a plurality of metal plates 22 (second metal plates). The laminated block body 2 is sandwiched between a ceiling plate 3 (third metal plate) and a floor plate 4 (fourth metal plate) in the stacking direction of the heat exchanger 1. The laminated block body 2 is a block body in which a plurality of metal plates 21 and a plurality of metal plates 22 are alternately stacked and bonded by diffusion bonding. Examples of diffusion bonding include solid-state bonding, hot pressure welding, and cold pressure welding. Because high-temperature fluid and low-temperature fluid exchange heat in the laminated block body 2, the metal plates 21 and 22 may also be referred to as heat transfer plates. In the example of FIG. 1 , the metal plate 22 is located in the uppermost layer of the laminated block body 2. The metal plate 21 may also be located in the uppermost layer of the laminated block body 2.

[0021] The ceiling panel 3 is made up of a plurality of stacked metal plates 30. The floor panel 4 is made up of a plurality of stacked metal plates 40. The ceiling panel 3 and the laminated block main body 2 are joined by diffusion bonding. The floor panel 4 and the laminated block main body 2 are joined by diffusion bonding. The ceiling panel 3 may be formed from a single metal plate having the same thickness as the thickness of the stacked metal plates 30, and the floor panel 4 may be formed from a single metal plate having the same thickness as the thickness of the stacked metal plates 40. Note that the joining by diffusion bonding is performed after the metal plates that form the ceiling panel 3, the laminated block main body 2, and the floor panel 4 have been stacked.

[0022] When the metal plate 22 is located in the top layer of the stacked block body 2, the ceiling plate 3 functions as a blocking plate that closes the flow paths, inlet / outlet ports, and through holes (which will be described later) provided in the metal plate 22 from the stacking direction.

[0023] The heat exchanger 1 has an upper surface 1u formed on the ceiling panel 3 side, a lower surface 1d formed on the floor panel 4 side, and a side surface 1w connected to the upper surface 1u and the lower surface 1d. An inlet / outlet pipe 53, an inlet / outlet pipe 54, an inlet / outlet pipe 55, and an inlet / outlet pipe 56 are provided on the upper surface 1u. For example, when the heat exchanger 1 is used as a condenser, the inlet / outlet pipe 53 serves as an inlet pipe for a low-temperature fluid (e.g., water), and the inlet / outlet pipe 54 serves as an outlet pipe for the low-temperature fluid. The inlet / outlet pipe 55 serves as an outlet pipe for a high-temperature fluid (e.g., a refrigerant), and the inlet / outlet pipe 56 serves as an inlet pipe for the high-temperature fluid. The inlet / outlet pipe 53 is inserted into an insertion hole 530 provided in the ceiling panel 3, the inlet / outlet pipe 54 is inserted into an insertion hole 540 provided in the ceiling panel 3, the inlet / outlet pipe 55 is inserted into an insertion hole 550 provided in the ceiling panel 3, and the inlet / outlet pipe 56 is inserted into an insertion hole 560 provided in the ceiling panel 3.

[0024] Headers 23, 24, 25, and 26 are formed at the four corners of the heat exchanger 1, penetrating the ceiling plate 3 and the laminated block main body 2 in the stacking direction. Header 23 communicates with inlet / outlet pipe 53. Header 24 communicates with inlet / outlet pipe 54. Header 25 communicates with inlet / outlet pipe 55. Header 26 communicates with inlet / outlet pipe 56. Headers 25 and 26 are connected to flow paths (described later) provided in metal plate 21. Header 23 and 24 are connected to flow paths (described later) provided in metal plate 22.

[0025] In the drawings of this embodiment, solid lines are drawn at the boundaries between the metal plates stacked in the stacking direction, but these solid lines may disappear without being visible in the diffusion-bonded heat exchanger 1. The Z-axis direction shown in the drawings corresponds to the stacking direction of the heat exchanger 1, the X-axis direction is approximately perpendicular to the Z-axis direction and corresponds to the direction from the inlet / outlet pipe 55 toward the inlet / outlet pipe 53, and the Y-axis direction is approximately perpendicular to the Z-axis direction and the X-axis direction and corresponds to the direction from the inlet / outlet pipe 55 toward the inlet / outlet pipe 54.

[0026] The metal plates 21, 22, 30, and 40 have high thermal conductivity and are made of the same material, such as aluminum, stainless steel, copper, an aluminum alloy, titanium, or a magnesium alloy.

[0027] 2(a) and 2(b) are schematic perspective views showing the metal plates forming the laminated block body before diffusion bonding, where Fig. 2(a) shows metal plate 21 and Fig. 2(b) shows metal plate 22.

[0028] As shown in FIG. 2A , the metal plate 21 has a rectangular planar shape, and is provided with a partition wall 211 (first partition wall), a plurality of protrusions 212 (first protrusions) protruding from the partition wall 211, and an outer periphery (first side wall portion) 213 surrounding the partition wall 211. The protrusions 212 have, for example, a circular shape when viewed from above. In the metal plate 21, there is a step between the partition wall 211 and the outer periphery 213, and the thickness of the partition wall 211 is formed thinner than the thickness of the outer periphery 213. In other words, a recess 216 is formed in the metal plate 21 by the partition wall 211 and the outer periphery 213. The recess 216 is surrounded by the outer periphery 213.

[0029] The metal plate 21 also has end faces 21e1, 21e2, 21e3, and 21e4. End face 21e2 is continuous with and intersects with end face 21e1. End face 21e3 is continuous with and intersects with end face 21e2. End face 21e4 is continuous with and intersects with end face 21e3. Furthermore, end face 21e1 is continuous with and intersects with end face 21e4. End face 21e1 is located on the opposite side of end face 21e3. End face 21e2 is located on the opposite side of end face 21e4.

[0030] By providing the partition wall 211 with the plurality of protrusions 212, each of the spaces between the plurality of protrusions 212 on the partition wall 211 (the spaces between adjacent protrusions 212 in the XY plane) becomes a flow path 215 (first flow path) of the metal plate 21. The flow path 215 is formed in the recess 216. The flow path 215 is formed by, for example, half-etching. The partition wall 211 and the plurality of protrusions 212 are provided on, for example, each of the plurality of metal plates 21 included in the laminated block main body 2.

[0031] A first inlet / outlet (through hole) 261, a second inlet / outlet (through hole) 251, a first through hole 231, and a second through hole 241 are provided at four corners of the metal plate 21. Each of the second inlet / outlet 251 and the first inlet / outlet 261 is connected to the flow path 215 and functions as an inlet / outlet header communicating with the flow path 215. Furthermore, a first isolation portion (seal portion) 2310 is provided in the metal plate 21 to surround the first through hole 231. The first isolation portion 2310 is formed continuously from the outer circumferential portion 213 on the flow path 215 side of the first through hole 231. The first isolation portion 2310 separates the flow path 215 and the first through hole 231. By providing the first isolation portion 2310 between the first through hole 231 and the flow path 215, the first through hole 231 and the flow path 215 are separated from each other. Furthermore, a second isolation portion (seal portion) 2410 is provided in the metal plate 21 so as to surround the second through hole 241. The second isolation portion 2410 is formed continuously from the outer peripheral portion 213 on the flow path 215 side of the second through hole 241. The second isolation portion 2410 separates the flow path 215 from the second through hole 241. By providing the second isolation portion 2410 between the second through hole 241 and the flow path 215, the second through hole 241 and the flow path 215 are separated from each other.

[0032] Furthermore, a groove 2311 (first groove) is formed in the first isolation portion 2310 of the metal plate 21 so as to surround the first through-hole 231. Figure 2(a) shows a cross section of the groove 2311 (cross section along the A1-A2 cross section line) at the position indicated by arrow C1. For example, one end 2311a of the groove 2311 is open at the end surface 21e1 of the metal plate 21, and the other end 2311b of the groove 2311 is open at the end surface 21e2 of the metal plate 21.

[0033] Further, a groove 2411 (second groove) is formed in the second isolation portion 2410 of the metal plate 21 so as to surround the second through-hole 231. For example, one end 2411a of the groove 2411 is open at the end face 21e3 of the metal plate 21, and the other end 2411b of the groove 2411 is open at the end face 21e4 of the metal plate 21.

[0034] For example, when the heat exchanger 1 ( FIG. 1 ) is used as a condenser, in the metal plate 21, the first inlet / outlet 261 serves as an inlet for a high-temperature fluid (first fluid), the high-temperature fluid flows through the flow path 215, and the second inlet / outlet 251 serves as an outlet for the high-temperature fluid. Also, a low-temperature fluid (second fluid) passes through each of the first through-hole 231 and the second through-hole 241.

[0035] As shown in FIG. 2( b ), the metal plate 22 has a rectangular planar shape, and is provided with a partition wall 221 (second partition wall), a plurality of protrusions 222 (second protrusions) protruding from the partition wall 221, and an outer periphery (second side wall portion) 223 surrounding the partition wall 221. The protrusions 222 have, for example, a circular shape when viewed from above. In the metal plate 22, there is a step between the partition wall 221 and the outer periphery 223, and the thickness of the partition wall 221 is thinner than the thickness of the outer periphery 223. In other words, a recess 226 is formed in the metal plate 22 by the partition wall 221 and the outer periphery 223. The recess 226 is surrounded by the outer periphery 223.

[0036] The metal plate 22 also has end faces 22e1, 22e2, 22e3, and 22e4. End face 22e2 is continuous with and intersects with end face 22e1. End face 22e3 is continuous with and intersects with end face 22e2. End face 22e4 is continuous with and intersects with end face 22e3. Furthermore, end face 22e1 is continuous with and intersects with end face 22e4. End face 22e1 is located on the opposite side of end face 22e3. End face 22e2 is located on the opposite side of end face 22e4.

[0037] By providing the plurality of protrusions 222 on the partition wall 221, each of the spaces between the plurality of protrusions 222 on the partition wall 221 (the spaces between adjacent protrusions 222 in the XY plane) becomes a flow path 225 (second flow path) of the metal plate 22. The flow path 225 is formed in the recess 226. The flow path 225 is formed by, for example, half-etching. The partition wall 221 and the plurality of protrusions 222 are provided on, for example, each of the plurality of metal plates 22 included in the laminated block main body 2.

[0038] A third inlet / outlet (through hole) 232, a fourth inlet / outlet (through hole) 242, a third through hole 262, and a fourth through hole 252 are provided at the four corners of the metal plate 22. The third inlet / outlet 232 and the fourth inlet / outlet 242 are each connected to the flow path 225 and function as an inlet / outlet header communicating with the flow path 225. A third isolation portion (seal portion) 2620 is provided in the metal plate 22 to surround the third through hole 262. The third isolation portion 2620 is formed continuously from the outer circumferential portion 223 on the flow path 225 side of the third through hole 262. The third isolation portion 2620 separates the flow path 225 and the third through hole 262. By providing the third isolation portion 2620 between the third through hole 262 and the flow path 225, the third through hole 262 and the flow path 225 are separated from each other. Furthermore, a fourth isolation portion (seal portion) 2520 is provided in the metal plate 22 so as to surround the fourth through hole 252. The fourth isolation portion 2520 is formed continuously from the outer peripheral portion 223 on the flow path 225 side of the fourth through hole 252. The fourth isolation portion 2520 separates the flow path 225 from the fourth through hole 252. By providing the fourth isolation portion 2520 between the fourth through hole 252 and the flow path 225, the fourth through hole 252 and the flow path 225 are separated from each other.

[0039] Furthermore, a groove 2521 (fourth groove) is formed in the fourth isolation portion 2520 of the metal plate 22 so as to surround the fourth through-hole 252. A cross section (cross section along the B1-B2 cross section line) of the groove 2521 at the position indicated by arrow C2 is shown in FIG. 2( b ). For example, one end 2521 a of the groove 2521 is open at the end surface 22 e 1 of the metal plate 22, and the other end 2521 b of the groove 2521 is open at the end surface 22 e 4 of the metal plate 22.

[0040] Furthermore, a groove 2621 (third groove) is formed in the third isolation portion 2620 of the metal plate 22 so as to surround the third through-hole 262. For example, one end 2621a of the groove 2621 is open at the end surface 22e3 of the metal plate 22, and the other end 2621b of the groove 2621 is open at the end surface 22e2 of the metal plate 22.

[0041] For example, when the heat exchanger 1 ( FIG. 1 ) is used as a condenser, in the metal plate 22, the third inlet / outlet 232 serves as an inlet for a low-temperature fluid (second fluid), the low-temperature fluid flows through the flow path 225, and the fourth inlet / outlet 242 serves as an outlet for the low-temperature fluid. Also, a high-temperature fluid (first fluid) passes through each of the third through-hole 262 and the fourth through-hole 252.

[0042] In the laminated block main body 2 (Figure 1), metal plates 21 (Figure 2(a)) and metal plates 22 (Figure 2(b)) are stacked alternately, so that a passage formed by groove 2311 is formed between the first isolation portion 2310 and the second metal plate 22 in contact with the first isolation portion 2310, a passage formed by groove 2411 is formed between the second isolation portion 2410 and the metal plate 22 in contact with the second isolation portion 2410, a passage formed by groove 2621 is formed between the third isolation portion 2620 and the metal plate 21 in contact with the third isolation portion 2620, and a passage formed by groove 2521 is formed between the fourth isolation portion 2520 and the metal plate 21 in contact with the fourth isolation portion 2520.

[0043] Furthermore, in the laminated block main body 2 ( FIG. 1 ), it is not necessary for both the groove 2311 and the groove 2411 to be formed in all of the multiple metal plates 21, and it is not necessary for both the groove 2521 and the groove 2621 to be formed in all of the multiple metal plates 22. That is, it is sufficient that a groove is formed in at least one of all of the isolation portions (the multiple first isolation portions 2310, the multiple second isolation portions 2410, the multiple third isolation portions 2620, and the multiple fourth isolation portions 2520) formed in the laminated block main body 2. However, if a groove is formed in all of the isolation portions formed in the laminated block main body 2, scratches formed in any of the isolation portions formed in the laminated block main body 2 can be detected more accurately.

[0044] In addition, it is not necessary for both the one end 2311a and the other end 2311b of the groove 2311 to be open to the end face of the metal plate 21, as long as either the one end 2311a or the other end 2311b is open to the end face of the metal plate 21. In addition, it is not necessary for both the one end 2411a and the other end 2411b of the groove 2411 to be open to the end face of the metal plate 21, as long as either the one end 2411a or the other end 2411b is open to the end face of the metal plate 21. In addition, it is not necessary for both the one end 2521a and the other end 2521b of the groove 2521 to be open to the end face of the metal plate 22, as long as either the one end 2521a or the other end 2521b is open to the end face of the metal plate 22. Furthermore, in the groove 2621, it is not necessary for both one end 2621a and the other end 2621b to be open to the end surface of the metal plate 22; it is sufficient if either one end 2621a or the other end 2621b is open to the end surface of the metal plate 22.

[0045] Furthermore, by alternately stacking the plurality of metal plates 21 and the plurality of metal plates 22 in the stacking direction, the first through hole 231 provided in the metal plate 21 and the third inlet / outlet 232 provided in the metal plate 22 are connected in the stacking direction to form the header 23 in the stacked block main body 2. Furthermore, the second through hole 241 provided in the metal plate 21 and the fourth inlet / outlet 242 provided in the metal plate 22 are connected in the stacking direction to form the header 24 in the stacked block main body 2. Furthermore, the second inlet / outlet 251 provided in the metal plate 21 and the fourth through hole 252 provided in the metal plate 22 are connected in the stacking direction to form the header 25 in the stacked block main body 2. Furthermore, the first inlet / outlet 261 provided in the metal plate 21 and the third through hole 262 provided in the metal plate 22 are connected in the stacking direction to form the header 26 in the stacked block main body 2.

[0046] FIG. 3(a) is a schematic perspective view showing a metal plate forming a ceiling panel before diffusion bonding, and FIG. 3(b) is a schematic perspective view showing a metal plate forming a floor panel before diffusion bonding.

[0047] As shown in FIG. 3( a), the metal plate 30 is a metal plate having a rectangular planar shape. Also, as shown in FIG. 3( b), the metal plate 40 is a metal plate having a rectangular planar shape. Here, a through hole 331, a through hole 341, a through hole 351, and a through hole 361 are provided at the four corners of the metal plate 30 shown in FIG. 3( a). By stacking a plurality of metal plates 30, the through holes 331 provided in the metal plates 30 are connected in the stacking direction to form an insertion hole 530 for the inflow / outflow pipe 53 in the ceiling panel 3. Furthermore, the through holes 341 provided in the metal plates 30 are connected in the stacking direction to form an insertion hole 540 for the inflow / outflow pipe 54 in the ceiling panel 3. Furthermore, the through holes 351 provided in the metal plates 30 are connected in the stacking direction to form an insertion hole 550 for the inflow / outflow pipe 55 in the ceiling panel 3. Furthermore, the through holes 361 provided in the metal plates 30 are connected in the stacking direction to form insertion holes 560 for the inflow / outflow pipes 56 in the ceiling plate 3 .

[0048] For example, when the heat exchanger 1 is used as a condenser, the through-hole 331 forms an insertion hole 530 for the inflow / outflow pipe 53 through which the low-temperature fluid flows in, the through-hole 341 forms an insertion hole 540 for the inflow / outflow pipe 54 through which the low-temperature fluid flows out, the through-hole 361 forms an insertion hole 560 for the inflow / outflow pipe 56 through which the high-temperature fluid flows in, and the through-hole 351 forms an insertion hole 550 for the inflow / outflow pipe 55 through which the high-temperature fluid flows out. Here, for example, the low-temperature fluid is water, and the high-temperature fluid is a refrigerant that changes phase between gas and liquid.

[0049] Fig. 4 is a schematic perspective view showing a part of the laminated block body, illustrating, as an example, the vicinity of the second through-hole 241 of one of the metal plates 21, with the metal plate 22 above that metal plate 21 removed.

[0050] 4 , a groove 2411 is formed in the second isolation portion 2410 of the metal plate 21 so as to surround the second through-hole 241. One end 2411a of the groove 2411 is open to the outside of the laminated block main body 2, and the other end 2411b of the groove 2411 is open to the outside of the laminated block main body 2. Similarly, one end 2311a of the groove 2311 of the metal plate 21 is open to the outside of the laminated block main body 2, and the other end 2311b is open to the outside of the laminated block main body 2; one end 2521a of the groove 2521 of the metal plate 22 is open to the outside of the laminated block main body 2, and the other end 2521b is open to the outside of the laminated block main body 2; and one end 2621a of the groove 2621 of the metal plate 22 is open to the outside of the laminated block main body 2, and the other end 2621b is open to the outside of the laminated block main body 2. As described above, the second through hole 241 provided in the metal plate 21 and the fourth inlet / outlet 242 provided in the metal plate 22 are connected in the stacking direction to form the header 24 in the stacked block main body 2.

[0051] (Function) Before describing the function of the heat exchanger 1 of this embodiment, the function of a heat exchanger according to a comparative example will be described. In the heat exchanger according to the comparative example, the metal plate 21 does not have the grooves 2311 and 2411, and the metal plate 22 does not have the grooves 2521 and 2621.

[0052] In metal plate 21, scratches may occur on the surface of first isolation portion 2310 or the surface of second isolation portion 2410 when handling the metal plate during etching, when stacking the metal plates, etc. Similarly, in metal plate 22, scratches may occur on the surface of fourth isolation portion 2520 or the surface of third isolation portion 2620.

[0053] For example, Figures 5(a) and (b) are schematic perspective views showing a portion of a laminated block main body according to a comparative example. Figure 5(a) shows a state in which no groove 2411 is provided in the second isolation portion 2410 of the metal plate 21, and further, a scratch 2415 is formed. The scratch 2415 spans the second isolation portion 2410 and reaches from the flow path 215 of the metal plate 21 to the header 24. When such a scratch 2415 is formed, even if it is a minute scratch with a shallow depth and a narrow width, as shown in Figure 5(b), the high-temperature fluid flowing through the flow path 215 of the metal plate 21 flows out into the header 24 through the scratch 2415, and the high-temperature fluid flowing through the flow path 215 mixes with the low-temperature fluid flowing through the header 24. Alternatively, conversely, the low-temperature fluid flowing through the header 24 may flow into the flow passage 215 of the metal plate 21 through the flaw 2415 , and the low-temperature fluid flowing through the header 24 may mix with the high-temperature fluid flowing through the flow passage 215 .

[0054] A leak test using He gas is an effective means for detecting the presence of such scratches 2415. In particular, in a diffusion-bonded heat exchanger, the scratches 2415 cannot be seen from the outside, so a leak test using He gas works effectively.

[0055] For example, Fig. 6 is a diagram showing an outline of a leak test using He gas in a comparative example. As shown in Fig. 6, an inlet / outlet pipe 54 connected to the header 24 is evacuated by a vacuum pump P. He gas as a test gas is then injected through an inlet / outlet pipe 56 connected to the header 26. Note that the inlet / outlet pipe 53 (Fig. 1) and the inlet / outlet pipe 55 (Fig. 1) are both closed. Also, in Fig. 6, the protrusions 212 of the metal plate 21 and the protrusions 222 of the metal plate 22 are omitted.

[0056] Here, the header 26 is in communication with the flow path 215 of the metal plate 21. If a scratch 2415 is formed in the second isolation portion 2410 of the metal plate 21, the scratch 2415 will become a leak path, causing He gas that has reached the flow path 215 to leak into the header 24. When the He gas reaches the inlet / outlet pipe 54, the He gas is detected by the leak detector D connected between the vacuum pump P and the inlet / outlet pipe 54. In other words, if the leak detector D detects He gas, it means that a scratch 2415 has been formed in the second isolation portion 2410 of any of the multiple metal plates 21.

[0057] However, in the comparative example, the He gas injected into the inlet / outlet pipe 56 passes through the inlet / outlet pipe 56, the header 26, the flow path 211 in the metal plate 21, the scratch 2415, the header 24, and the inlet / outlet pipe 54. This inevitably increases the distance between the point where the test gas is injected (the inlet of the inlet / outlet pipe 56) and the point where the test gas is detected (the leak detector D).

[0058] This lengthens the detection time from the injection of He gas to the detection of He gas. As a result, the response of the leak detection becomes slow, and there is a high possibility that a leak may actually exist but not be detected, resulting in a latent defect occurring, where a product deemed to be good is found to be defective during use. In particular, in the case of a stacked microchannel heat exchanger made up of multiple metal plates with fine flow paths, the presence of numerous fine flow paths within the heat exchanger results in a narrow and long path through which He gas must pass for leak detection. This increases the flow resistance experienced by the He gas as it flows through the path, potentially making it difficult to accurately detect the presence or absence of a leak. Furthermore, the longer detection time requires a large amount of test gas, resulting in increased testing costs.

[0059] 7( a) and 7(b) show a state in which a scratch 2415 is formed in the second isolation portion 2410 of the metal plate 21 of this embodiment. For example, when the scratch 2415 is formed in the second isolation portion 2410 of the metal plate 21 as shown in FIG. 7(a), as shown in FIG. 7(b), a path 21p is formed that allows He gas to flow from the outside (side surface 1w) of the laminated block main body 2 to the header 24 via the other end 2411b of the groove 2411, the groove 2411, and the scratch 2415. Alternatively, a path can be formed that allows He gas to flow from one end 2411a of the groove 2411 to the header 24 via the groove 2411 and the scratch 2415.

[0060] FIG. 8 is a diagram showing an example of an outline of a leak test using He gas in this embodiment. Here, the inlet / outlet pipe 53 ( FIG. 1 ), the inlet / outlet pipe 55 ( FIG. 1 ), and the inlet / outlet pipe 56 ( FIG. 1 ) are all closed. In the heat exchanger 1 of this embodiment, a path 21p is formed that allows He gas to flow from the other end 2411b of the groove 2411 of the heat exchanger 1 to the header 24. As a result, as shown in FIG. 8 , for example, He gas can be injected from the other end 2411b of the heat exchanger 1 by spraying He gas onto the other end 2411b of the second groove 2411 exposed on the side surface 1w of the heat exchanger 1.

[0061] The He gas injected from the other end 2411b of the heat exchanger 1 passes through the path 21p, the header 24, and the inlet / outlet pipe 54. Therefore, the distance between the point where the test gas is injected (the other end 2411b) and the point where the test gas is detected (the leak detector D) is shorter than in the comparative example.

[0062] This shortens the detection time from when He gas is injected until it is detected. As a result, the response of leak detection improves, leaks can be detected more reliably, and the occurrence of latent defects can be further reduced. Furthermore, the shorter detection time requires only a small amount of test gas, which helps prevent increases in inspection costs.

[0063] For example, Fig. 9 shows the relationship between the time (horizontal axis) after the test gas is injected into the heat exchanger and the amount of leaked test gas (vertical axis). As shown in Fig. 9, the time until He gas is detected is shorter in this embodiment than in the comparative example.

[0064] Thus, according to this embodiment, in a stacked heat exchanger 1, it is possible to more quickly determine whether the fluid inlet / outlet and the fluid flow path are connected by a scratch so that they are separated by a separating section formed on the stacked metal plates.

[0065] Although the embodiments of the present invention have been described above, it is needless to say that the present invention is not limited to the above-described embodiments and various modifications can be made. Each embodiment is not limited to an independent form, and can be combined as far as technically possible.

[0066] DESCRIPTION OF SYMBOLS 1...Heat exchanger 1u...Upper surface 1d...Lower surface 1w...Side surface 2...Laminated block main body 3...Ceiling plate 4...Floor plate 21...Metal plate (first metal plate) 21e1, 21e2, 21e3, 21e4, 22e1, 22e2, 22e3, 22e4...End surface 21p...Path 22...Metal plate (second metal plate) 23, 24, 25, 26...Header 30, 40...Metal plate 53, 54, 55, 56...Inlet / outlet pipes 211, 221...Partition wall 212, 222...Protrusion 213, 223...Outer periphery 215...Flow path (first flow path) 216, 226...Recess 225...Flow path (second flow path) 231...First through hole 232...Third inlet / outlet 241...Second through hole 242...Fourth inlet / outlet 251...Second inlet / outlet 252...Fourth through hole 261...First inlet / outlet 262...Third through hole 331, 341, 351, 361...Through holes 2310...First isolation portion 2311...Groove (first groove) 2311a, 2411a, 2521a, 2621a...One end 2311b, 2411b, 2521b, 2621b...Other end 2410...Second isolation portion 2411...Groove (second groove) 2415...Scratch 2520...Fourth isolation portion 2521...Groove (fourth groove) 2620...Third isolation portion 2621...Groove (third groove) 530, 540, 550, 560...Insertion hole

Claims

1. A heat exchanger in which a plurality of metal plates are stacked and bonded, the plurality of metal plates including a plurality of first metal plates and a plurality of second metal plates, the plurality of first metal plates and the plurality of second metal plates being stacked alternately, each of the plurality of first metal plates being provided with a first flow path through which a first fluid flows, a first inlet and a second inlet connected to the first flow path, a first through hole and a second through hole through which a second fluid passes, a first isolation part separating the first flow path from the first through hole, and a second isolation part separating the first flow path from the second through hole, and each of the plurality of second metal plates being provided with a second flow path through which the second fluid flows, a third inlet and a fourth inlet connected to the second flow path, a third through hole and a fourth through hole through which the first fluid passes, a third isolation part separating the second flow path from the third through hole, and a fourth isolation part separating the second flow path from the fourth through hole, a laminated block body in which the plurality of first metal plates and the plurality of second metal plates are alternately laminated, wherein a groove having one end open to the outside of the laminated block body is formed in at least one of the first isolation portion, the second isolation portion, the third isolation portion, and the fourth isolation portion.

2. A heat exchanger according to claim 1, wherein the other end of said groove is open to the outside of said laminated block body.

3. A heat exchanger as claimed in claim 1 or 2, wherein the groove is formed in at least one of the following: between the first isolation portion and the second metal plate in contact with the first isolation portion; between the second isolation portion and the second metal plate in contact with the second isolation portion; between the third isolation portion and the first metal plate in contact with the third isolation portion; and between the fourth isolation portion and the first metal plate in contact with the fourth isolation portion.

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