Heat exchanger

Abstract

A heat exchanger includes plate fin stacked body (4) configured by stacking plate fins (3) each having a flow channel through which a first fluid such as a refrigerant flows. Plate fin (3) includes a pair of plates brazed to each other, and the pair of plates is provided with the flow channel therebetween. Plate fin (3) is provided with tubular parts (13) each protruding to the outside of each of the pair of plates in portions of header region X connected to the flow channel of plate fin (3), and by fitting and brazing tubular parts (13) of adjacent plate fins (3) to each other, the portions of header regions X of adjacent plate fins (3) are coupled and fixed together.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a stack-type plate fin heat exchanger.BACKGROUND ART

[0002] PTL 1 discloses a plate heat exchanger. A bypass passage and a main passage are formed upstream of first passages and second passages between adjacent ones of first heat transfer plates and second heat transfer plates. The bypass passage allows first fluid flowing from an inflow port of the first fluid or second fluid flowing from an inflow port of the second fluid to pass a side farther than a corresponding one of adjacent holes while spreading in a vertical direction in a front view and then flow into an inner fin or a corrugated heat transfer surface. The main passage allows the first fluid flowing from the inflow port of the first fluid or the second fluid flowing from the inflow port of the second fluid to directly flow toward the inner fin or the corrugated heat transfer surface without routing through the bypass passage. A flat space is formed around an entire circumference of each of the adjacent holes, and the first fluid or the second fluid flowing through the main passage and the first fluid or the second fluid flowing through the bypass passage merge in the space between a circumferential wall and the inner fin or the corrugated heat transfer surface.

[0003] PTL 2 discloses a heat exchanger and a refrigeration system using the same, and more particularly a plate-fin stack type heat exchanger configured by laminating plate-like plate fins through which refrigerant flows.

[0004] PTL 3 discloses a conventional stack-type plate fin heat exchanger. As shown in Figs. 7 and 8, this stack-type plate fin heat exchanger includes plate fin stacked body 102 in which plate fins 101 having flow channels through which a first fluid such as a refrigerant flows are stacked, end plates 103 stacked and disposed on both sides of plate fin stacked body 102, and inlet and outlet pipes 104 and 105 into which the first fluid flowing through the flow channels of plate fin stacked body 102 flows or from which the first fluid flows out. A second fluid flows between layers of plate fins 101 of plate fin stacked body 102 to allow heat to be exchanged between the first fluid and the second fluid. Through-holes 107 are provided at appropriate positions on a peripheral edge of header region 106 being an inlet and outlet portion of the channel of the first fluid in plate fin stacked body 102. By passing bolts 109 through through-holes 107 with reinforcing plate 108 interposed therebetween, portions of the header regions of plate fins 101 are connected and fixed together.

[0005] PTL 4 discloses a plate heat exchanger having first heat transfer plates and second heat transfer plates laminated atop one another, and each including a plate portion in which an inflow / outflow hole is formed, a first outer circumferential wall portion or second outer circumferential wall portion that extends on one surface side of the plate portion and that defines a channel together with a plate portion adjacent to the one surface side, and a first inner fin or a second inner fin that is attached to an inside portion of the channel. The first inner fin is mounted at a position, spaced apart from a first fluid inflow / outflow hole, inside the channel, on the one surface of the plate portion and the second inner fin is mounted at a position, spaced apart from a second fluid inflow / outflow hole inside the channel, on the one surface of the plate portion.

[0006] PTL 5 discloses a plate type heat exchanger.

[0007] PTL 6 discloses a heat exchanger unit having tubes each having a body section and at least one of an inner pipe section and an outer pipe section extending from the body section and defining an opening at an end. Each of the inner pipe section and the outer pipe section has a first portion and a second portion adjacent to the first portion. The tubes are stacked such that the body sections are spaced from each other. Further, the inner pipe section is received in the outer pipe section such that the first portion of the inner pipe section overlaps the first portion of the outer pipe section, and the second portions of the inner and outer pipe sections are located on opposite sides of the overlapped first portions. The first and second portions of the inner pipe section have an outer diameter smaller than an inner diameter of the first and second portions of the outer pipe section.Citation ListPatent Literature

[0008] PTL 1: EP 3 415 854 A1 PTL 2: JP 2019 100564 A PTL 3: WO 2018 / 074342 A PTL 4: US 2020 / 0072561 A1 PTL 5: JP 2005 326072 A PTL 6: US 2007 / 0039717 A1 SUMMARY OF THE INVENTION

[0009] The present disclosure provides a stack-type plate fin heat exchanger in which a configuration of coupling and fixing portions of header regions of plate fins is simplified, and deformation of the plate fins due to insufficient coupling and fixing strength is suppressed.

[0010] The stack-type plate fin heat exchanger according to the present disclosure includes tubular parts provided at appropriate positions on peripheral edges of the header region of the plate fin. The tubular parts of the adjacent plate fins are fitted to each other to cause the header regions of the plate fins to be coupled and fixed.BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Fig. 1 is a perspective view showing an external appearance of a stack-type plate fin heat exchanger according to a first exemplary embodiment. Fig. 2 is an enlarged perspective view showing header regions of the heat exchanger. Fig. 3 is an enlarged sectional view showing the header regions of the heat exchanger. Fig. 4 is an enlarged sectional view showing a main part of the header regions of the heat exchanger. Fig. 5 is an enlarged sectional view of a portion indicated by A in Fig. 4. Fig. 6 is an exploded perspective view of plate fins of the heat exchanger according to the first exemplary embodiment. Fig. 7 is a perspective view of a conventional stack-type plate fin heat exchanger. Fig. 8 is a perspective view showing the conventional stack-type plate fin heat exchanger in a state before the header regions are coupled and fixed together. DESCRIPTION OF EMBODIMENT(Knowledge and the like underlying the present disclosure)

[0012] The stack-type plate fin heat exchanger described in Patent Literature 1 is a heat exchanger proposed by the inventors of the present invention. At the time when the inventors arrived at the present disclosure, in the heat exchanger described in Patent Literature 1, because header regions 106 where the first fluid such as the refrigerant flowing through the flow channel gathers are easily deformed by the pressure of the first fluid, reinforcing plate 108 is placed on the outer surface of header regions 106, and the portions of header regions 106 are coupled and fixed together by bolts 109. As a result of intensive studies by the inventors, it has been found that because reinforcing plate 108, the bolts 109, and the like are required in the conventional configuration, there is a problem that the configuration is complicated, the weight of the entire heat exchanger increases, and assembling work for reinforcing plate 108 and bolts 109 is required, and productivity decreases.

[0013] In view of these problems, the inventors of the present disclosure have made the subject matter of the present disclosure to solve the problems.

[0014] The present disclosure provides a heat exchanger in which a configuration of coupling and fixing portions of header regions of plate fins is simplified and deformation of the plate fins in the portions of the header regions is suppressed to improve reliability.

[0015] Hereinafter, an exemplary embodiment is described in detail with reference to the accompanying drawings. It is noted that a more detailed description than needed may be omitted. For example, detailed description of already well-known matters and repeated description of substantially the same configuration are omitted in some cases. This is to avoid an unnecessary redundancy in the following description and to facilitate understanding by those skilled in the art.

[0016] The exemplary embodiment described below shows an example of the present disclosure, and configurations, functions, and operations described in the present exemplary embodiment are mere examples and do not limit the present disclosure.(First exemplary embodiment)

[0017] Hereinafter, the heat exchanger according to a first exemplary embodiment of the present disclosure is described with reference to Figs. 1 to 6.[1-1. Configuration]

[0018] Fig. 1 is a perspective view showing an appearance of stack-type plate fin heat exchanger (hereinafter, simply referred to as heat exchanger) 1 according to the first exemplary embodiment, Fig. 2 is an enlarged perspective view showing header regions of the stack-type plate fin heat exchanger, Fig. 3 is an enlarged sectional view showing the header regions of the stack-type plate fin heat exchanger, Fig. 4 is an enlarged sectional view showing a main part of the header regions of the stack-type plate fin heat exchanger, Fig. 5 is an enlarged sectional view of a portion indicated by A in Fig. 4, and Fig. 6 is an exploded perspective view of plate fins of the stack-type plate fin heat exchanger according to the first exemplary embodiment.

[0019] As shown in Figs. 1 to 6, heat exchanger 1 according to the present exemplary embodiment includes inlet pipe (inlet port header) 2, plate fin stacked body 4 including a plurality of plate fins 3 that are stacked together, and outlet pipe (outlet port header) 5 allowing the refrigerant having flown through flow channels provided in plate fins 3 to be discharged. The refrigerant as the first fluid flows into the inlet pipe (inlet port header) 2. In the example of the present exemplary embodiment, the plurality of plate fins 3 each have a rectangular plate shape.

[0020] End plates 6a and 6b are respectively provided on both sides (upper side and lower side in Fig. 1) in the stacking direction of plate fin stacked body 4. The shape of end plates 6a and 6b and the shape of plate fins 3 are substantially the same in plan view. End plates 6a and 6b are each made of a plate material having rigidity, and are formed by, for example, grinding and machining metal material, such as aluminum, an aluminum alloy, or stainless steel.

[0021] Note that end plates 6a and 6b and the plurality of plate fins 3 are stacked and joined integrally by brazing. End plates 6a and 6b and the plurality of plate fins 3 may be joined by other heat-resistant fixing methods such as a method using a chemical joining member.

[0022] Further, in the present exemplary embodiment, in plate fin stacked body 4 formed by stacking plate fins 3, plate fins 3 are coupled and fixed at both ends in the longitudinal direction of plate fin stacked body 4. A configuration of coupling and fixing plate fin stacked body 4 is described later.

[0023] Note that, as shown in Fig. 6, plate fin 3 is formed by joining a pair of long plates 3a and 3b by brazing. The pair of plates 3a and 3b has a recessed groove serving as flow channel 7. By joining the pair of plates 3a and 3b, inlet header flow channel 9 and outlet header flow channel 10 connected to flow channel 7 via communication channel 8 are formed. Flow channel 7 provided in plates 3a and 3b are disposed along the longitudinal direction of plates 3a and 3b. Flow channel 7 is configured to make a U-turn at the ends of plates 3a and 3b. On one end side of plates 3a and 3b, inlet header flow channel 9 connected to outgoing flow channel 7a and outlet header flow channel 10 connected to return flow channel 7b are collectively disposed. Slit 11 that suppresses heat transfer between the first fluid flowing through outgoing flow channel 7a and the first fluid flowing through return flow channel 7b is disposed between outgoing flow channel 7a and return flow channel 7b. As described above, plate fins 3 are stacked together with end plates 6a and 6b and brazed to form plate fin stacked body 4. Each of inlet pipe 2 and outlet pipe 5 are connected to a corresponding one of inlet header flow channel 9 and outlet header flow channel 10 of plate fin stacked body 4.

[0024] Next, a configuration for coupling and fixing both ends of plate fin stacked body 4 is described. In plate fin 3 of the present exemplary embodiment, through-holes 12 are provided in a peripheral edge of header region X where inlet header flow channel 9 and outlet header flow channel 10 of plate fin 3 are located (see, for example, Figs. 3 and 6). As shown in Fig. 6, tubular part 13 is disposed in an erected manner in a portion of each of the pair of plates 3a and 3b provided with through-hole 12. In other words, through-hole 12 is disposed inside the wall surface constituting tubular part 13. Tubular parts 13 are disposed protruding outward from each of the pair of plates 3a and 3b. As shown in Figs. 4 and 5, tubular part 13 is fitted to tubular part 13 of another plate fin 3 adjacent in the stacking direction. By brazing tubular parts 13 of adjacent plate fins 3 to each other, header regions X (see Fig. 1 and others) of adjacent plate fins 3 are coupled and fixed to each other. Tubular part 13 is disposed protrudingly on the surface opposite to the brazed surface of the plates 3a and 3b to which brazing material is applied in advance. By fitting tubular parts 13 of adjacent plate fins 3 to each other and causing the brazing material to be melted and solidified on the brazed surface on the inner peripheral surface of any one of tubular parts 13 to integrate tubular parts 13 to each other, header regions X of plate fin stacked body 4 formed by stacking the plurality of plate fins 3 are coupled and fixed together.

[0025] Although not illustrated, similar through-holes 12 are also provided and tubular parts 13 are disposed at the end of each plate fin 3 on the side opposite to header region X. By fitting and brazing tubular parts 13 to each other, the ends of plate fin stacked body 4 formed by stacking plate fins 3 are coupled and fixed together.

[0026] As shown in Fig. 6, tubular parts 13 each erected on through-hole 12 are disposed surrounding inlet header flow channel 9 and outlet header flow channel 10. In the example shown in Fig. 6, each of tubular parts 13 is provided on a line connecting the approximate centers of inlet header flow channel 9 and outlet header flow channel 10. Specifically, tubular part 13 is provided to overlap, in at least a part of the outer periphery of tubular part 13, on a line connecting the approximate centers of outlet header flow channel 10 and outlet header flow channel 10. A fitting clearance between tubular parts 13 of adjacent plate fins 3 is less than or equal to 0.2 mm, preferably 0.2 mm to 0.1 mm.

[0027] Note that, in the example of the present exemplary embodiment, at least one tubular part 13 among tubular parts 13 to be fitted to each other, that is, in the example shown in Fig. 6, tubular part 13 of upper plate 3a among the pair of plates 3a and 3b has a tapered shape.[1-2. Operation]

[0028] Functional effect of heat exchanger 1 configured as described above is described below.

[0029] When heat exchanger 1 according to the present exemplary embodiment is, for example, incorporated into a refrigeration system and used under evaporation conditions, the refrigerant in a gas-liquid two-phase state that is the first fluid flows from inlet pipe 2 into inlet header flow channel 9 of plate fin stacked body 4. The refrigerant having flowed into inlet header flow channel 9 flows to a group of outgoing flow channels 7a through communication channels 8 of plate fins 3. The refrigerant having flowed to the group of outgoing flow channels 7a of each plate fin 3 makes a U-turn and flows from outlet pipe 5 in a gas state to the refrigerant circuit of the refrigeration system through return flow channel 7b. While flowing through outgoing flow channel 7a, the refrigerant exchanges heat with the air (second fluid) passing between plate fins 3 of plate fin stacked body 4.

[0030] At this time, because heat transfer between the refrigerant flowing through the group of outgoing flow channels 7a and the refrigerant flowing through return flow channel 7b is suppressed by slit 11, high heat exchange efficiency is exhibited. In the case where heat exchanger 1 is used as a condenser, the flow of the first fluid is opposite to that when the heat exchanger 1 is used as an evaporator. That is, inlet pipe 2 and inlet header flow channel 9 respectively serve as an outlet pipe and an outlet header flow channel, and outlet pipe 5 and outlet header flow channel 10 respectively serve as an inlet pipe and an inlet header flow channel.

[0031] In heat exchanger 1, because the opening area of inlet header flow channel 9 is larger than the opening areas of other flow channels, stress concentrates on the portion of header regions X where inlet header flow channel 9 is disposed, and the portions of the header regions X tend to be greatly deformed in the stacking direction. However, in heat exchanger 1 according to the present exemplary embodiment, because the portions of header regions X are firmly coupled and fixed together, deformation of the portions of header regions X is suppressed, and thus heat exchanger 1 according to the present exemplary embodiment can be a highly reliable heat exchanger.

[0032] More specifically, in heat exchanger 1 of the present exemplary embodiment, tubular parts 13 are provided in header region X of each of plates 3a and 3b constituting plate fin 3. Tubular parts 13 of adjacent plate fins 3 are fitted and brazed to each other. The header regions X of adjacent plate fins 3 are thus coupled and fixed together

[0033] Therefore, tabular parts 13 of adjacent plate fins 3 are fitted to each other, and tubular parts 13 are connected in a columnar shape in the stacking direction. Further, because tubular parts 13 are joined to each other by brazing material, the joining strength is further increased by the solidified brazing material, and a more robust fixing structure is obtained. Therefore, the coupling strength of the portions of the header regions is greatly improved, the rigidity of the plate fin stacked body is improved, and a highly reliable heat exchanger can be obtained.

[0034] In addition, because a reinforcing plate, bolts, and the like for securing the coupling strength at the portions of the header regions as in the conventional art are not required, the configuration can be simplified as compared with the conventional heat exchanger using the reinforcing plate, the bolts, and the like.

[0035] In addition, because workability at the time of manufacturing the heat exchanger is improved, productivity can be improved. That is, according to the configuration of the present exemplary embodiment, header regions X can be coupled and fixed together by just inserting a guide-pin jig into through-hole 12, stacking and directly putting plates 3a and 3b in a melting furnace, and brazing plates 3a and 3b. The number of man-hours can be reduced, the man-hours being required in the conventional configuration to assemble using the reinforcing plate and the bolts separately from the brazing work, and as a result, the workability at the time of manufacturing is greatly improved. Therefore, productivity of the heat exchanger is greatly improved.

[0036] In the heat exchanger of the present exemplary embodiment, tubular parts 13 are disposed surrounding each of inlet header flow channel 9 and outlet header flow channel 10. Therefore, even when a large amount of the first fluid flows in a concentrated manner to cause a high pressure to be applied around inlet header flow channel 9 and outlet header flow channel 10 of each of plates 3a and 3b, that is, at the portion of header region X, the pressure resistance around inlet header flow channel 9 and the pressure resistance around outlet header flow channel 10 can respectively be substantially uniformly improved to enhance the pressure resistance of the entire portion of header region X. In the example of the present exemplary embodiment, each tubular part 13 is provided such that at least a part of the outer periphery of tubular part 13 overlaps on the line connecting the approximate centers of inlet header flow channel 9 and outlet header flow channel 10. Therefore, the portions of header regions X are coupled together by tubular parts 13 in the vicinity of the line connecting the substantial centers of the inlet header flow channel 9 and outlet header flow channel 10, and the pressure resistance of the portions of header regions X can be more uniformly and reliably improved to prevent deformation of plate fin 3.

[0037] In the example of the present exemplary embodiment, at least one of tubular parts 13 provided in the pair of plates 3a and 3b is tapered. As a result, even if there is a dimensional tolerance in tubular parts 13 fitted to each other, tubular parts 13 reliably come into contact with each other at least at a part thereof, and thus tubular parts 13 can be reliably fixed to each other with the brazing material. Therefore, the coupling strength of the portions of header regions X becomes strong, and the pressure resistance can be more reliably improved.

[0038] In addition, the fitting clearance between tubular parts 13 to be fitted is set to less than or equal to 0.2 mm, and in the example of the present exemplary embodiment, is set to be in the range of 0.2 mm to 0.1 mm. As a result, in between tubular parts 13, the melted brazing material substantially uniformly goes around the entire circumference of tubular parts 13 and is solidified. Therefore, the strength of a joint between tubular parts 13 including the brazing material is reliably improved, and the pressure resistance of the portions of header regions X can be further reliably improved.[Other exemplary embodiments]

[0039] Hereinafter another exemplary embodiment is exemplified.

[0040] In the first exemplary embodiment, the heat exchanger is exemplified, in which flow channel 7 through which the first fluid flows makes a U-turn and inlet header flow channel 9 connected to outgoing flow channel 7a and outlet header flow channel 10 connected to return flow channel 7b are collectively provided on one end side of plate fin 3. However, flow paths 7 may be linearly disposed and not make a U-turn, and inlet header flow channel 9 may be provided on one end side of plate fin 3 and outlet header flow channel 10 may be provided on the other end side of plate fin 3. Further, tubular parts 13 may be provided surrounding each of inlet header flow channel 9 and outlet header flow channel 10, and then plate fins 3 may be coupled and fixed to each other.

[0041] In the first exemplary embodiment, tubular parts 13 provided on the pair of plates 3a and 3b constituting plate fin 3 are described as tubular parts having a circular section. However, the sectional shape of each of the tubular parts is not limited to a circular shape, and may be any shape such as a polygonal shape including a hexagonal shape or an elliptical shape. Note that the tubular parts may each be a tubular part having a discontinuous wall surface with a cut, such as tubular part 13a provided in the middle of slit 11 shown in Fig. 6.

[0042] In the first exemplary embodiment, it has been exemplified that at least one of tubular parts 13 of adjacent plate fins 3 is tapered. However, neither of tubular parts 13 of adjacent plate fins 3 may be tapered. Alternatively, both of tubular parts 13 of adjacent plate fins 3 may be tapered. In this case, taper angles of two tubular parts 13 to be fitted are preferably slightly different from each other. Alternatively, although not illustrated, a distal end of one of tubular parts 13 of adjacent plate fins 3 may be subjected to nesting processing.[1-3. Effects and the like]

[0043] As described above, the heat exchanger according to the present disclosure includes a plate fin stacked body in which the plate fins having the flow channels through which the first fluid such as the refrigerant flows are stacked, the end plates respectively stacked and disposed on both sides of the plate fin stacked body, and inlet header flow channel and outlet header flow channel through which the first fluid flowing through the flow channels of the plate fin stacked body passes. The second fluid flows between layers of the plate fins of the plate fin stacked body to allow heat to be exchanged between the first fluid and the second fluid. The plate fin includes the pair of plates brazed to each other, and the pair of plates is provided with the flow channel therebetween. The tubular part is provided at an appropriate position on the periphery of the portion of the header region of the plate fin provided with the inlet header flow channel and the outlet header flow channel connected to the flow channel. The tubular parts of the adjacent plate fins are fitted to each other. In the present exemplary embodiment, the tubular parts of the adjacent plate fins are fitted to each other by brazing to couple and fix the header regions of the plate fins together.

[0044] As a result, the coupling strength of the portions of the header regions can be improved with a simple configuration without using the reinforcing plate, bolts, and the like, the rigidity of the plate fin stacked body can be improved, and a highly reliable heat exchanger can be obtained.

[0045] The tubular parts are preferably provided surrounding the inlet header flow channel and the outlet header flow channel. As a result, the pressure resistance of the portions of the header regions can be more reliably improved.

[0046] In addition, at least one of the tubular parts provided on the pair of plates preferably has a tapered shape or a shape obtained by being subjected to nesting processing. Therefore, the bonding of the tubular parts becomes more reliable and the pressure resistance in the portions of the header regions can be more reliably improved.

[0047] Note that the fitting clearance between the tubular parts disposed in the adjacent plate fins and fitted to each other is preferably set to less than or equal to 0.2 mm. Therefore, the bonding of the tubular parts becomes more reliable and the pressure resistance in the portions of the header regions can be still more reliably improved.

[0048] The stack-type plate fin heat exchanger according to the present disclosure has been described above using the exemplary embodiments, but the present disclosure is not limited thereto. That is, the exemplary embodiments disclosed herein is illustrative in all points and not restrictive, the scope of the present disclosure is shown by the claims.INDUSTRIAL APPLICABILITY

[0049] The heat exchanger of the present disclosure can improve the coupling strength of the portions of the header regions of the plate fins with a simple configuration, improve the rigidity of the plate fin stacked body, and provide a highly reliable heat exchanger. Accordingly, the present invention can be applied to a wide range of applications including heat exchangers for domestic and industrial air conditioners and various refrigerating devices, and thus shows great industrial value.REFERENCE MARKS IN THE DRAWINGS

[0050] 1heat exchanger 2inlet pipe 3plate fin 3a, 3bplate 4plate fin stacked body 5outlet pipe 6a, 6bend plate 7flow channel 7aoutgoing flow channel 7breturn flow channel 8communication channel 9inlet header flow channel 10outlet header flow channel 11slit 12through-hole 13, 13atubular part

Claims

1. A heat exchanger (1) comprising: a plate fin stacked body (4) including a plurality of plate fins (3) stacked, the plurality of plate fins each having a flow channel (7) through which a first fluid flows; end plates (6a, 6b) respectively disposed on both sides of the plate fin stacked body (4) in a stacking direction of the plurality of plate fins (3); an inlet header flow channel (9) through which the first fluid flows into the flow channel; and an outlet header flow channel (10) through which the first fluid flows out from the flow channel, wherein the plurality of plate fins (3) each include a pair of plates (3a, 3b) brazed to each other to provide the flow channel between the pair of plates, and tubular parts (13) each disposed in a portion of a header region (X) of the heat exchanger and protruding outward from a corresponding one of the pair of plates (3a, 3b), the header region being a region where the inlet header flow channel (9) and the outlet header flow channel (10) are disposed, and the plurality of plate fins (3) include adjacent plate fins whose tubular parts are fitted to each other.

2. The heat exchanger according to claim 1, wherein the tubular parts (13) of each of the plurality of plate fins (3) are disposed surrounding at least one of the inlet header flow channel (9) and the outlet header flow channel (10) in plan view of each of the plurality of plate fins.

3. The heat exchanger according to claim 1 or 2, wherein at least one of the tubular parts (13) of each of the plurality of plate fins (3) has a tapered shape or a shape obtained by nesting processing.

4. The heat exchanger according to any one of claims 1 to 3, wherein the adjacent plate fins among the plurality of plate fins (3) has a fitting clearance between the tubular parts (13) of less than or equal to 0.2 mm.

5. The heat exchanger according to any one of claims 1 to 4, wherein the tubular parts (13) of the adjacent plate fins among the plurality of plate fins (3) are brazed to each other to connect portions of header regions (X) of the adjacent plate fins.

6. The heat exchanger according to any one of claims 1 to 5, wherein the tubular parts (13) protruding outward from the corresponding one of the pair of plates (3a, 3b) are disposed at a same position in plan view of each of the plurality of plate fins (3).

7. The heat exchanger according to any one of claims 1 to 6, wherein the plurality of plate fins (3) that are stacked together have a second fluid flowing between the plurality of plate fins to allow heat to be exchanged between the first fluid and the second fluid.

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