Method for producing plate-type heat exchanger, and plate-type heat exchanger

Abstract

A method for producing a plate-type heat exchanger includes: a step in which a second brazing material is disposed on a portion of the outer surface of an outermost-side heat transfer plate, the portion surrounding a through-hole; a step in which a base end of a pipe member is inserted into the through-hole from the outer surface of the outermost-side heat transfer plate and a larger-diameter portion thereof is made to adjoin the outer surface of the outermost-side heat transfer plate, thereby attaching the pipe member to the outermost-side heat transfer plate; and a step in which the outermost-side heat transfer plate to which the pipe member has been attached is heated to melt the second brazing material and a clad layer, thereby brazing the base end of the pipe member onto the inner wall of the through-hole of the outermost-side heat transfer plate.

Description

Plate heat exchanger manufacturing method and plate heat exchanger

[0001] The present disclosure relates to a method for manufacturing a plate heat exchanger and a plate heat exchanger.

[0002] Some heat exchangers have pipe members connected to them so that fluid flows in and out of a flow path space within the device from an external device.

[0003] For example, Patent Document 1 discloses a heat exchanger in which an inlet pipe is connected to a header tank. In this heat exchanger, one end of the inlet pipe is provided with a ring-shaped protrusion extending circumferentially on the outer wall surface away from the pipe end face. Meanwhile, the header tank is formed with a through-hole into which the one end of the inlet pipe can be inserted. Furthermore, the inner wall surface of the header tank is covered with a clad layer formed of brazing material. In the heat exchanger described in Patent Document 1, the one end of the inlet pipe is inserted into the through-hole of the header tank until the ring-shaped protrusion contacts the outer wall surface of the header tank, and then the clad layer on the inner wall surface of the header tank is melted to braze the one end of the inlet pipe to the inner wall of the through-hole of the header tank.

[0004] Japanese Patent Application Laid-Open No. 2005-156000

[0005]

[0003] A heat exchanger includes a plate-type heat exchanger having a plurality of stacked heat transfer plates with fluid flow passages formed between them. Even in such a plate-type heat exchanger, a pipe member, for example, a pipe joint, may be connected to the outermost heat transfer plate, which is located at the outermost position of the plurality of heat transfer plates, to allow fluid to flow in and out of an external device. In this case, the method for joining an inlet pipe of a heat exchanger to a header tank, as described in Patent Document 1, may be applied to joining the outermost heat transfer plate to the pipe joint.

[0006] However, when the method for joining a pipe fitting and an outermost heat transfer plate described in Patent Document 1 is used to join an inlet pipe and a header tank of a heat exchanger, a clad layer is formed on the inner surface of the outermost heat transfer plate, and the clad layer is melted to braze the pipe fitting to the outermost heat transfer plate. In this case, the brazing filler metal may not sufficiently wet and spread from the inner surface to the outer surface of the outermost heat transfer plate. As a result, the pipe fitting and the outermost heat transfer plate may not be joined with sufficient strength.

[0007] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a plate heat exchanger and a method for manufacturing a plate heat exchanger in which tube members are joined to the outermost heat transfer plate with high strength.

[0008] To achieve the above object, the present disclosure provides a method for manufacturing a plate heat exchanger comprising a plurality of heat transfer plates and tubular members. In the plate heat exchanger, the plurality of heat transfer plates are stacked with fluid flow passages therebetween, and at least the outermost heat transfer plate has through holes for allowing fluid to flow in and out of the fluid flow passages, and a first brazing filler metal is disposed around the through holes and on the inner surface side of the through holes. The tubular members each have a base end and a large-diameter portion having an outer diameter larger than that of the base end, and the base end is inserted through the through hole and the large-diameter portion is adjacent to the outer surface of the outermost heat transfer plate, allowing fluid to flow in and out of the fluid flow passages. The method for manufacturing a plate-type heat exchanger includes the steps of: arranging a second brazing filler metal on the outer surface side of the outermost heat transfer plate and around the through holes; attaching the tube members to the outermost heat transfer plate by inserting the base ends of the tube members into the through holes from the outer surface side of the outermost heat transfer plate and aligning the large diameter portions adjacent to the outer surface of the outermost heat transfer plate; and heating the outermost heat transfer plate to which the tube members are attached, thereby melting the first brazing filler metal and the second brazing filler metal and brazing the base ends of the tube members to the inner walls of the through holes in the outermost heat transfer plate.

[0009] According to the configuration of the present disclosure, a method for manufacturing a plate-type heat exchanger includes a step of melting a brazing filler metal arranged on the outer surface of the outermost heat transfer plate around the through hole and a first brazing filler metal arranged on the inner surface of the outermost heat transfer plate around the through hole to braze the base end of the tube member to the inner wall of the through hole of the outermost heat transfer plate. Therefore, during the brazing step, the brazing filler metal sufficiently penetrates both the outer surface and the inner surface of the outermost heat transfer plate. As a result, the tube member can be joined to the outermost heat transfer plate with high strength.

[0010] a perspective view of a plate heat exchanger according to a first embodiment of the present disclosure; an exploded perspective view of a plate heat exchanger according to a first embodiment of the present disclosure; a perspective view of a pipe joint included in the plate heat exchanger according to the first embodiment of the present disclosure; a perspective view of a reinforcing plate and a pipe joint included in the plate heat exchanger according to the first embodiment of the present disclosure; a flowchart of a method for manufacturing a plate heat exchanger according to the first embodiment of the present disclosure; a cross-sectional view of a pipe joint to which a metal foil is attached in a metal foil attaching step included in the method for manufacturing a plate heat exchanger according to the first embodiment of the present disclosure; a cross-sectional view of a reinforcing plate when a pipe joint is attached in a pipe joint attaching step included in the method for manufacturing a plate heat exchanger according to the first embodiment of the present disclosure; an enlarged cross-sectional view of a portion of a reinforcing plate to which a pipe joint is attached in a pipe joint attaching step included in the method for manufacturing a plate heat exchanger according to the first embodiment of the present disclosure; FIG. 11 is an enlarged cross-sectional view of a region IX shown in FIG. 8; FIG. 12 is a cross-sectional view of a modified example of a pipe joint used in a metal foil attaching step included in the method for manufacturing a plate-type heat exchanger according to embodiment 1 of the present disclosure; FIG. 13 is an enlarged cross-sectional view of a portion of a modified example of a reinforcing plate and metal foil brazed in a brazing step included in the method for manufacturing a plate-type heat exchanger according to embodiment 1 of the present disclosure; FIG. 14 is a perspective view of a reinforcing plate and a pipe joint included in a plate-type heat exchanger according to embodiment 2 of the present disclosure;

[0011] A plate heat exchanger and a manufacturing method thereof according to an embodiment of the present disclosure will be described in detail below with reference to the drawings. In the drawings, identical or equivalent parts are designated by the same reference numerals. In the Cartesian coordinate system XYZ shown in the drawings, the longitudinal direction of the rectangular heat transfer plates of the plate heat exchanger is the up-down direction, and the lateral direction is the front-to-rear direction. The up-down direction is the Z-axis, the front-to-rear direction is the Y-axis, and the direction perpendicular to the Z-axis and Y-axis is the X-axis. This coordinate system will be referenced as appropriate below.

[0012] (Embodiment 1) A manufacturing method for a plate heat exchanger according to embodiment 1 is a manufacturing method in which a foil made of brazing material is arranged on the surface of the reinforcing plate on the side where the pipe fitting is inserted, and a clad material made of brazing material is provided on the surface of the reinforcing plate opposite to the side where the pipe fitting is inserted, in order to supply a sufficient amount of brazing material to increase the brazing strength in the brazing process after assembling by inserting pipe fittings into through holes in the reinforcing plate, which is the outermost heat transfer plate. First, the configuration of the plate heat exchanger to be manufactured will be described with reference to Figures 1 to 4.

[0013] Fig. 1 is a perspective view of a plate heat exchanger 1A according to the first embodiment. Fig. 2 is an exploded perspective view of the plate heat exchanger 1A. Fig. 3 is a perspective view of pipe joints 61-64 provided in the plate heat exchanger 1A. Fig. 4 is a perspective view of a reinforcing plate 30A and a pipe joint 62 provided in the plate heat exchanger 1A. For ease of understanding, Fig. 1 omits the standing wall 11 of the heat transfer plate 10 and the standing wall 21 of the heat transfer plate 20. Fig. 2 also illustrates the clad materials 31 and 41 of the reinforcing plates 30A and 40A as separate members.

[0014] As shown in FIGS. 1 and 2, the plate heat exchanger 1A includes a plurality of heat transfer plates 10, 20 stacked alternately, and reinforcing plates 30A, 40A that reinforce the stacked heat transfer plates 10, 20.

[0015] The heat transfer plates 10 and 20 are components for exchanging heat between two types of fluids, a first fluid and a second fluid. Specifically, the heat transfer plate 10 is made of a metal with high thermal conductivity, such as stainless steel. As shown in FIG. 2 , the heat transfer plate 10 is formed in the shape of a rectangular plate with rounded corners. The outer periphery of the heat transfer plate 10 is surrounded by an upright wall 11, forming a flow path space for the first fluid to flow through. The flow path space of the heat transfer plate 10 is provided with an inner fin 12 to facilitate heat transfer of the first fluid. Furthermore, a metal foil 13 made of pure copper or a copper alloy is disposed on the right side of the heat transfer plate 10, covering the right side of the heat transfer plate 10 and functioning as a brazing material during manufacturing, to bond the heat transfer plate 10 to the heat transfer plate 20 when stacked together. In this specification, the brazing material refers to a component formed from a brazing material.

[0016] In contrast, the heat transfer plate 20 is also made of the same material as the heat transfer plate 10 and is formed in the same rectangular shape as the heat transfer plate 10. The outer periphery of the heat transfer plate 20 is also surrounded by upright walls 21, thereby forming a flow path space for flowing a second fluid separate from the first fluid. Inner fins 22 are also provided in this flow path space of the heat transfer plate 20 to improve heat transfer efficiency. Furthermore, a metal foil 23 made of pure copper or a copper alloy is also arranged on the right surface of the heat transfer plate 20, covering the right surface of the heat transfer plate 20 and functioning as a brazing material during manufacturing.

[0017] The heat transfer plates 10 and 20 are stacked alternately with the plate surfaces of the above-described shape facing left and right, the upstanding wall 11 or 21 facing left, and the right surface covered with metal foil 13 or 23. Furthermore, inlet and outlet holes 14, 15 and communication holes 16, 17 are formed at the four corners of the heat transfer plate 10. Communication holes 24, 25 and inlet and outlet holes 26, 27 are formed at the four corners of the heat transfer plate 20, which are positioned to overlap the inlet and outlet holes 14, 15 and communication holes 16, 17 in the left and right directions. By stacking the heat transfer plates 10 and 20 alternately, the inlet and outlet holes 14, 15 of one heat transfer plate 10 are connected to the communication holes 24, 25 of the adjacent heat transfer plate 20 on the right, which has a peripheral wall portion protruding to the right. This allows the first fluid to flow in and out of the heat transfer plate 20 to the heat transfer plate 10 on its right side through the inlet and outlet holes 14, 15. The inlet and outlet holes 26, 27 of the heat transfer plate 20 also have a peripheral wall portion that protrudes to the right and connects to the communication holes 16, 17 of the adjacent heat transfer plate 10 on the right side. As a result, the inlet and outlet holes 26, 27 allow the second fluid to flow in and out between the heat transfer plate 10 and the heat transfer plate 20 located further to the right.

[0018] The heat transfer plates 10 and 20 have this configuration and are stacked alternately in the left-right direction, allowing the first fluid and the second fluid to flow through them and transferring heat from the first fluid and the second fluid to the heat transfer plates 10 and 20. As a result, when the first fluid and the second fluid are flowed through the heat transfer plates 10 and 20, heat is exchanged between the first fluid and the second fluid. Meanwhile, in this specification, the alternately stacked heat transfer plates 10 and 20 will be referred to as a stack 50, and the stack 50 is sandwiched between reinforcing plates 30A and 40A to reinforce the heat transfer plates 10 and 20.

[0019] The reinforcing plates 30A and 40A are formed in the shape of rectangular plates, which is the same shape as the heat transfer plates 10 and 20. The reinforcing plate 30A is disposed on the left side of the stack 50 with its plate surface facing left and right. In contrast, the reinforcing plate 40A is disposed on the right side of the stack 50 with its plate surface facing left and right. With this arrangement, the reinforcing plates 30A and 40A sandwich and reinforce the heat transfer plates 10 and 20.

[0020] As shown in FIG. 2 , the reinforcing plate 30A has through holes 32 and 33 formed therein for supplying the first fluid to the stack 50 or discharging the first fluid from the stack 50. Pipe fittings 61 and 62 are connected to the through holes 32 and 33, respectively. To facilitate connection with the pipe fittings 61 and 62, the opening peripheries of the through holes 32 and 33 are chamfered as shown in FIG. 9 , which will be described later. As a result, burrs are removed from the opening peripheries of the through holes 32 and 33. The pipe fittings 61 and 62 are joined to the reinforcing plate 30A by brazing them to the inner walls of the through holes 32 and 33, as will be described later. By removing burrs from the opening peripheries of the through holes 32 and 33, molten brazing material can more easily flow into the inner walls of the through holes 32 and 33 during the brazing process.

[0021] Furthermore, a plate-shaped clad material 31 made of wax is provided on the right surface of the reinforcing plate 30A to firmly bond it to the laminate 50 during manufacturing.

[0022] Similarly, the reinforcing plate 40A is also formed with through holes 42, 43 for supplying the second fluid to the stack 50 or discharging the second fluid from the stack 50, and pipe fittings 63, 64 are connected to the through holes 42, 43, respectively. Although not shown, the opening peripheries of the through holes 42, 43 are also chamfered to facilitate the flow of molten brazing material in the brazing process. Furthermore, in order to firmly bond the reinforcing plate 40A to the stack 50, a plate-shaped clad material 41 made of the same brazing material as the clad material 31 is provided on the left surface side.

[0023] For ease of understanding, Fig. 2 shows the reinforcing plate 30A and the clad material 31 as separate members. However, the reinforcing plate 30A and the clad material 31 are assembled together, and pipe fittings 61, 62 shown in Fig. 3 are connected to the reinforcing plate 30A and the clad material 31 in this state. Similarly, Fig. 2 shows the reinforcing plate 40A and the clad material 41 as separate members. However, the reinforcing plate 40A and the clad material 41 are assembled together, and pipe fittings 63, 64 shown in Fig. 3 are connected to the reinforcing plate 40A and the clad material 41 in this state. The pipe fittings 61, 62 are joined to the reinforcing plate 30A by melting the clad material 31 and allowing the brazing material of the clad material 31 to penetrate between the inner walls of the through holes 32, 33 of the reinforcing plate 30A and the pipe fittings 61, 62. In addition, the pipe fittings 63, 64 are joined to the reinforcing plate 40A by melting the clad material 41 and allowing the brazing material that is the material of the clad material 41 to penetrate between the inner walls of the through holes 42, 43 of the reinforcing plate 40A and the pipe fittings 63, 64.

[0024] However, simply infiltrating the molten brazing filler metal from the clad material 31 may not sufficiently penetrate to the left side of the reinforcing plate 30A, which is opposite the side where the clad material 31 is located, between the inner walls of the through holes 32, 33 of the reinforcing plate 30A and the pipe fittings 61, 62. As a result, the joint strength of the pipe fittings 61, 62 may be reduced. Similarly, simply infiltrating the molten brazing filler metal from the clad material 41 may not sufficiently penetrate to the right side of the reinforcing plate 40A, which is opposite the side where the clad material 41 is located, between the inner walls of the through holes 42, 43 of the reinforcing plate 40A and the pipe fittings 63, 64. As a result, the joint strength of the pipe fittings 63, 64 may be reduced.

[0025] Therefore, in the plate-type heat exchanger 1A, in order to increase the joining strength by supplying brazing filler metal from the left surface of the reinforcing plate 30A, which is opposite to the surface on which the clad material 31 is located, a ring-shaped metal foil 70 formed from brazing filler metal is provided around the through-hole 33 of the reinforcing plate 30A into which the pipe fitting 62 is inserted, and on the left surface side of the reinforcing plate 30A, as shown in Fig. 4. Furthermore, a bead portion 65 is provided on the cylindrical surface of the pipe fitting 62 to sandwich and hold the metal foil 70 between the reinforcing plate 30A and the left surface of the reinforcing plate 30A.

[0026] Although not shown, metal foil 70 is provided around the through hole 32 of the reinforcing plate 30A, into which the pipe fitting 61 is inserted, and on the left surface of the reinforcing plate 30A to increase the bonding strength. A bead portion 65 is also provided on the cylindrical surface of the pipe fitting 61 to hold the metal foil 70 in place.

[0027] Similarly, metal foil 70 (not shown) is provided around each of the through holes 42, 43 of the reinforcing plate 40A into which the pipe fittings 63, 64 are inserted, and on the right side of the reinforcing plate 40A, in order to increase the joining strength by supplying brazing filler metal from the right side of the reinforcing plate 40A, which is opposite the side on which the clad material 41 is located. Furthermore, bead portions 65 are also provided on the cylindrical surfaces of the pipe fittings 63, 64 to sandwich and hold each metal foil 70 between them and the right side of the reinforcing plate 40A.

[0028] Next, a method for manufacturing the plate heat exchanger 1A having such a configuration will be described in detail with reference to FIGS.

[0029] Fig. 5 is a flowchart of a method for manufacturing the plate heat exchanger 1A. In the method for manufacturing the plate heat exchanger 1A shown in Fig. 5, the heat transfer plates 10, 20, metal foils 13, 23, reinforcing plates 30A, 40A, clad materials 31, 41, and pipe joints 61, 62, 63, 64 having the shapes, sizes, and numbers described above are prepared in advance. Also, the clad material 31 is attached to the reinforcing plate 30A, and the clad material 41 is attached to the reinforcing plate 40A in advance.

[0030] First, in the manufacturing method of the plate heat exchanger 1A, a metal foil attachment step is performed (step S1) as shown in Fig. 5. In this metal foil attachment step, metal foil 70 is attached to each of the pipe fittings 61, 62, 63, and 64. Fig. 6 shows an example in which the metal foil 70 is attached to the pipe fitting 62 of the pipe fittings 61, 62, 63, and 64.

[0031] FIG. 6 is a cross-sectional view of the pipe joint 62 to which the metal foil 70 has been attached in the metal foil attaching step included in the manufacturing method of the plate heat exchanger 1A.

[0032] As shown in FIG. 6, the pipe fitting 62 has a base end 66 that is attached to the through hole 33 of the reinforcing plate 30A, a bead portion 65 that is located closer to the tip end than the base end 66, i.e., on the −X side, and a tip end 68 in which a groove 67 for attaching an O-ring is formed.

[0033] As will be described later, the pipe fitting 62 is attached to the reinforcing plate 30A by inserting the base end 66 into the through hole 33 of the reinforcing plate 30A and then crimping the base end 66. To enable this, the base end 66 is formed in the shape of a circular tube having an outer diameter D1 that can be inserted into the through hole 33 of the reinforcing plate 30A. Furthermore, in order to enable crimping while inserted into the through hole 33 of the reinforcing plate 30A, the length of the base end 66 in the extension direction is longer than the total thickness of the clad material 31, the reinforcing plate 30A, and the metal foil 70, although this is not shown in FIG. 6 .

[0034] The bead portion 65 has a shape that protrudes outward from the base end 66. Specifically, the bead portion 65 is formed by crushing a straight pipe in the tube axial direction. As a result, it has a circular flange shape with an outer diameter D2 larger than the outer diameter D1 of the base end 66. As a result, when the base end 66 is passed through a ring of the metal foil 70 (described later), the bead portion 65 abuts against the surface of the metal foil 70 to determine its position. Furthermore, when the base end 66 is inserted into the through-hole 33 of the reinforcing plate 30A, the side surfaces of the bead portion 65, i.e., the +X surface and the −X surface, are flat to enable the metal foil 70 to be sandwiched between the base end 66 and the reinforcing plate 30A without any gaps. In other words, the bead portion 65 has flat surfaces 653 and 654 that are perpendicular to the +X and −X directions.

[0035] In contrast, the tip portion 68 has a circular pipe shape, just like the base end portion 66. The outer diameter D3 of the tip portion 68 is larger than the outer diameter D1 of the base end portion 66, but smaller than the outer diameter D2 of the bead portion 65. As a result, in the pipe fitting 62, the outer diameter D2 of the bead portion 65 is the largest. This prevents the brazing filler metal from reaching the tip portion 68 from the base end portion 66, beyond the bead portion 65, during the brazing process described below.

[0036] The pipe joint 62 having such a configuration is made of metal, for example, stainless steel, in order to obtain strength.

[0037] On the other hand, the metal foil 70 is formed of the same brazing material as the clad materials 31, 41, for example, pure copper or a copper alloy. The metal foil 70 is formed in a ring shape. Specifically, the metal foil 70 is formed in a flat, annular shape having an inner diameter D4 larger than the outer diameter D1 of the base end portion 66 and the diameter of a through hole 33 (described later) in the reinforcing plate 30A, and an outer diameter D5 larger than the outer diameter D2 of the bead portion 65. The thickness T2 of the metal foil 70 is thinner than the thickness T1 of the bead portion 65. For example, when the thickness T1 of the bead portion 65 is 1.5 to 2.0 mm, the thickness T2 of the metal foil 70 is approximately 0.15 to 0.20 mm.

[0038] In order to prevent forgetting to attach the metal foil 70 during manufacturing, it is desirable that the outer diameter D5 of the metal foil 70 be larger than the outer diameter D2 of the bead portion 65 by an amount that can be visually confirmed. For example, it is desirable that the outer diameter D5 of the metal foil 70 be larger than the outer diameter D2 of the bead portion 65 by 3 to 4 mm.

[0039] In the metal foil attachment step shown in Figure 5, the metal foil 70 having such a configuration is attached to the above-mentioned pipe fitting 62. More specifically, the base end 66 of the pipe fitting 62 is passed through the annular hole in the metal foil 70, and the flat surface 654 of the bead portion 65 of the pipe fitting 62, shown in Figure 6, is brought adjacent to the metal foil 70. In this way, the metal foil 70 is attached to the pipe fitting 62. Although not shown, the metal foil 70 is attached to each of the pipe fittings 61, 63, and 64 by performing the same procedure as for the pipe fitting 62.

[0040] 5, the metal foil attaching step is followed by the pipe joint attaching step (step S2). An example of attaching the pipe joint 62 of the pipe joints 61, 62, 63, and 64 to the reinforcing plate 30A is shown in FIGS.

[0041] Fig. 7 is a cross-sectional view of the reinforcing plate 30A when the pipe joints 62 are attached in a pipe joint attaching step included in the manufacturing method of the plate heat exchanger 1A. Fig. 8 is an enlarged cross-sectional view of a part of the reinforcing plate 30A to which the pipe joints 62 are attached in the pipe joint attaching step.

[0042] In the pipe fitting installation process, the base end 66 of the pipe fitting 62 is inserted into the through hole 33 of the reinforcing plate 30A, to which the clad material 31 shown in Figure 7 is attached, from the side opposite to the side on which the clad material 31 of the reinforcing plate 30A is located, i.e., from the -X side. At this time, the base end 66 of the pipe fitting 62 is inserted into the through hole 33 of the reinforcing plate 30A until the metal foil 70 attached to the pipe fitting 62 contacts the -X side of the reinforcing plate 30A and the metal foil 70 is sandwiched between the flat portion 654 of the bead portion 65 of the pipe fitting 62 and the reinforcing plate 30A. This exposes the end face of the base end 66 of the pipe fitting 62 on the +X side of the clad material 31, as shown in Figure 7.

[0043] Next, a frustum-shaped punch 80, whose tip outer diameter is smaller than the inner diameter of the base end 66 and whose base outer diameter is larger than the outer diameter of the base end 66, is pressed into the internal space of the pipe fitting 62, which opens at the end face of the exposed base end 66, to crimp the base end 66. As a result, as shown in FIG. 8 , the inner diameter of the base end 66 increases toward the +X side, and the -X end of the base end 66 becomes larger than the diameter of the through-hole 33 of the reinforcing plate 30A. That is, the -X end of the base end 66 has a larger diameter than the outer diameter D1 shown in FIG. 6 . As a result, the pipe fitting 62 is fixed to the reinforcing plate 30A. Furthermore, because the punch 80 presses the reinforcing plate 30A in the -X direction, the reinforcing plate 30A is tightly attached to the metal foil 70, and the metal foil 70 is tightly attached to the bead portion 65. As a result, the size of the gap G between the reinforcing plate 30A and the bead portion 65 is adjusted to the thickness T2 of the metal foil 70. This makes the size of the gap G constant, and makes it easy for the brazing filler metal to penetrate by capillary action in the brazing process described below.

[0044] The through hole 33 of the reinforcing plate 30A, into which the base end 66 of the pipe fitting 62 is inserted, is connected to the through hole 37 of the clad material 31 shown in Figure 8. It is desirable that the through hole 37 be larger than the outer diameter of the base end 66 after it has been crimped. By having such a through hole 37 in the clad material 31, it is possible to prevent the peripheral portion of the through hole in the clad material 31 from getting between the inner wall of the through hole 33 of the reinforcing plate 30A and the base end 66, which would otherwise cause the pipe fitting 62 to tilt relative to the reinforcing plate 30A.

[0045] Pipe joint 61 is fixed to reinforcing plate 30A by the same procedure as for pipe joint 62. Pipe joints 63 and 64 are fixed to reinforcing plate 40A by the same procedure as for pipe joint 62.

[0046] Next, as shown in Figure 5, a lamination process is performed (step S3). Specifically, the heat transfer plates 10, 20 and the metal foils 13, 23 are stacked in the above-mentioned arrangement to assemble the laminate 50. Furthermore, the laminate 50 is sandwiched between the reinforcing plate 30A to which the clad material 31 and the pipe fittings 61, 62 are attached, and the reinforcing plate 40A to which the clad material 41 and the pipe fittings 63, 64 are attached.

[0047] Following the stacking step, a pressurizing step (step S4) is performed. In this pressurizing step, the stack 50, in which the reinforcing plates 30A and 40A are assembled, is compressed by applying pressure in the stacking direction. This causes the heat transfer plates 10 and 20, the metal foils 13 and 23, and the reinforcing plates 30A and 40A that form the stack 50 to adhere to one another.

[0048] After compressing the laminate 50, a brazing process is performed (step S5). Specifically, the laminate 50 assembled with the reinforcing plates 30A and 40A is placed in a furnace and heated to a temperature at which the brazing filler metal, which is the material of the clad materials 31 and 41, melts. This melts the metal foils 13 and 23 between the heat transfer plates 10 and 20 of the laminate 50, the metal foil 70 attached to the pipe fitting 62, and the clad materials 31 and 41. As a result, the molten brazing filler metal penetrates into the gaps between the components. The brazing of the pipe fitting 62 and the reinforcing plate 30A at this time is shown in Figure 9.

[0049] Fig. 9 is an enlarged cross-sectional view of region IX shown in Fig. 8 of a pipe fitting 62 brazed in a brazing step included in the manufacturing method of the plate-type heat exchanger 1A. Note that a minute gap is formed between the bead portion 65 of the pipe fitting 62 and the metal foil 70, allowing molten brazing filler metal to penetrate by capillary action. For ease of understanding, this minute gap is enlarged and emphasized in Fig. 9. The path of brazing filler metal penetration is also shown.

[0050] In the brazing process, when the clad material 31 is heated to a temperature at which the brazing filler metal melts, the clad material 31 melts. As a result, as shown by arrow A1 in Figure 9, the molten brazing filler metal wets and spreads into the gap between the base end portion 66 of the pipe fitting 62 and the clad material 31, and as a result, penetrates into the gap between the base end portion 66 and the inner wall of the through hole 33 of the reinforcing plate 30A.

[0051] Meanwhile, a metal foil 70 is disposed on the side of the reinforcing plate 30A opposite the side on which the clad material 31 is disposed, i.e., on the -X side of the reinforcing plate 30A. Therefore, when the metal foil 70 is heated to a temperature at which the brazing filler metal melts, the metal foil 70 melts and supplies the molten brazing filler metal (hereinafter simply referred to as brazing filler metal in the brazing process) to the -X side of the reinforcing plate 30A. At this time, the outer diameter D2 of the bead portion 65 is the largest among the parts of the pipe fitting 62, and the thickness T2 of the bead portion 65 is sufficiently greater than the thickness T1 of the metal foil 70. Therefore, the brazing filler metal is prevented from spreading beyond the bead portion 65 toward the -X side. This allows the brazing filler metal to spread toward the +X side of the bead portion 65 rather than the -X side. 9, the brazing filler metal spreads into the gap between the bead portion 65 of the pipe fitting 62 and the metal foil 70 or the reinforcing plate 30A, and penetrates into the gap between the base end portion 66 of the pipe fitting 62 and the inner wall of the through hole 33 of the reinforcing plate 30A. As a result, the brazing filler metal penetrates into the gap between the base end portion 66 and the inner wall of the through hole 33 not only from the +X face side of the reinforcing plate 30A but also from the -X face side.

[0052] When the filler metal that has penetrated from the +X side of the reinforcing plate 30A and the filler metal that has penetrated from the -X side come into contact in the gap between the base end 66 and the inner wall of the through hole 33, the filler metal can pass through the gap between the base end 66 and the inner wall of the through hole 33 and move toward the +X side of the reinforcing plate 30A or toward the opposite -X side, as shown by arrow A3 in Figure 9. This allows the filler metal to sufficiently fill not only the gap between the base end 66 and the inner wall of the through hole 33, but also the gap between the base end 66 and the clad material 31 on the +X side of the reinforcing plate 30A and the gap between the bead portion 65 and the metal foil 70 on the -X side of the reinforcing plate 30A. At this time, even if the size of these gaps varies due to dimensional variations and assembly variations, the filler metal moves through the gap between the base end 66 and the inner wall of the through hole 33, so these gaps are sufficiently filled with filler metal. As a result, fillets 34 and 35 are formed in the gap between the base end portion 66 and the clad material 31 and in the gap between the bead portion 65 and the metal foil 70 .

[0053] After heating for a certain period of time in the brazing process, the laminate 50 assembled with the reinforcing plates 30A and 40A is cooled. This solidifies the brazing filler. As a result, the pipe fitting 62 is joined to the reinforcing plate 30A. As described above, the brazing filler sufficiently penetrates not only the gap between the base end 66 and the inner wall of the through hole 33 of the reinforcing plate 30A but also the gap between the base end 66 and the clad material 31 and the gap between the bead portion 65 and the metal foil 70, forming fillets 34, 35. This results in a strong bond between the pipe fitting 62 and the reinforcing plate 30A. Although not shown, when brazing the pipe fitting 61 to the reinforcing plate 30A, the brazing filler sufficiently penetrates the gap between the pipe fitting 61 and the reinforcing plate 30A, just as in the brazing of the pipe fitting 62 to the reinforcing plate 30A. This results in a strong bond between the pipe fitting 61 and the reinforcing plate 30A. Furthermore, when brazing the pipe fittings 63, 64 to the reinforcing plate 40A, the brazing filler metal sufficiently penetrates into the gaps between the pipe fittings 63, 64 and the reinforcing plate 40A, just as it does when brazing the pipe fitting 62 to the reinforcing plate 30A. As a result, the pipe fittings 63, 64 are also firmly joined to the reinforcing plate 40A. In this way, the pipe fittings 61-64 are firmly joined to the reinforcing plates 30A, 40A, resulting in the manufacture of a plate-type heat exchanger 1A with high strength.

[0054] The reinforcing plates 30A and 40A described above are components that correspond to the heat transfer plates defined in the present disclosure because they transfer heat. The reinforcing plates 30A and 40A are an example of the outermost heat transfer plates defined in the present disclosure. The clad materials 31 and 41 are an example of the first brazing filler metal or clad layer defined in the present disclosure. The pipe joints 61-64 are an example of the pipe member defined in the present disclosure. The bead portion 65 is an example of the large diameter portion defined in the present disclosure. The metal foil 70 is an example of the second brazing filler metal defined in the present disclosure.

[0055] The metal foil attaching step and the pipe joint attaching step are steps of arranging the metal foil 70 on the reinforcing plates 30A and 40A. As can be seen from this, the metal foil attaching step and the pipe joint attaching step are examples of a step of arranging a second brazing filler metal as defined in the present disclosure. Also, the pipe joint attaching step is an example of a step of attaching a tube member to the outermost heat transfer plate as defined in the present disclosure.

[0056] As described above, the manufacturing method of the plate heat exchanger 1A according to the first embodiment includes a brazing step of melting the ring-shaped metal foil 70, which is disposed on the −X face, i.e., outer face, of the reinforcing plate 30A and surrounds the through holes 32, 33, and the clad material 31, which is disposed on the +X face, i.e., inner face, of the reinforcing plate 30A and is formed of brazing material, to braze the base ends 66 of the pipe fittings 61, 62 to the inner walls of the through holes 32, 33 of the reinforcing plate 30A. Because the brazing step allows the brazing material to sufficiently penetrate both the −X face and the +X face of the reinforcing plate 30A, the pipe fittings 61, 62 can be joined to the reinforcing plate 30A with high strength.

[0057] In the method of joining the inlet pipe and header tank of a heat exchanger described in Patent Document 1, it is considered to use flux in the brazing process to increase the fluidity of the brazing material. In contrast, in the manufacturing method of the plate-type heat exchanger 1A, the metal foil 70 arranged on the outer surface of the reinforcing plate 30A and the clad material 31 arranged on the inner surface of the reinforcing plate 30A are melted, and the brazing material is supplied from both sides of the reinforcing plate 30A, so the fluidity of the brazing material can be increased without using flux.

[0058] Furthermore, in the manufacturing method of the plate heat exchanger 1A, for brazing, the metal foil 70 is simply placed on the outer surface of the reinforcing plate 30A, rather than providing a clad material 31 as is done on the inner surface. This simplifies manufacturing and reduces material costs.

[0059] The manufacturing method for the plate-type heat exchanger 1A also includes a pipe fitting attachment process in which the base ends 66 of the pipe fittings 61, 62 are crimped to sandwich the metal foil 70 between the bead portions 65 of the pipe fittings 61, 62 and the reinforcing plate 30A. As a result, the distance between the bead portions 65 and the reinforcing plate 30A is constant. In other words, the size of the gap between the bead portions 65 and the reinforcing plate 30A is determined to be constant. Therefore, in the brazing process, the brazing filler metal can stably penetrate into this gap. This prevents the brazing filler metal from insufficiently penetrating the gap between the bead portions 65 and the reinforcing plate 30A, resulting in a decrease in joint strength.

[0060] The outer diameter D5 of the metal foil 70 is larger than the outer diameter D2 of the bead portion 65 of the pipe fittings 61, 62. Therefore, when the metal foil 70 is attached in the metal foil attachment process, the metal foil 70 protrudes from the bead portion 65. As a result, it is easy for the worker to check whether the metal foil 70 has been attached. This makes it possible to prevent forgetting to attach the metal foil 70.

[0061] The outer diameter D2 of the bead portion 65 of the pipe fittings 61, 62 is the largest among the pipe fittings 61, 62. As a result, during the brazing process, it is possible to prevent the brazing filler metal from flowing from the metal foil 70 over the bead portion 65 and wrapping around to the tip portion 68. Furthermore, since the thickness T1 of the bead portion 65 is greater than the thickness T2 of the metal foil 70, it is possible to further prevent the brazing filler metal from flowing around to the tip portion 68.

[0062] 6, the pipe fitting 62 has straight pipe portions 655, 656 arranged on either side of the bead portion 65. It is desirable that these straight pipe portions 655, 656 have lower wettability with molten brazing filler metal than the bead portion 65. This is because, even if the brazing filler metal passes over the bead portion 65 and enters the -X side during the brazing process, it is difficult for the brazing filler metal to further wet and spread toward the -X side.

[0063] The bead portion 65 is formed by ironing using a mold, and as a result of this processing, the surface roughness of the straight pipe portions 655, 656 becomes smaller than the surface roughness of the bead portion 65. As a result, the straight pipe portions 655, 656 have lower wettability than the bead portion 65. For this reason, it is desirable that the straight pipe portions 655, 656 have lower wettability than the bead portion 65 by forming the bead portion 65 by ironing.

[0064] Furthermore, it is desirable that the straight pipe portion 655 has lower wettability with respect to the molten brazing filler metal than the inner wall of the groove 67. The inner wall of the groove 67 is processed to have a small surface roughness in order to improve the sealing performance of the O-ring. This is because the low wettability of the straight pipe portion 655 can prevent the brazing filler metal from wetting and spreading into the groove 67.

[0065] The straight pipe portion 655 is an example of a pipe portion that is adjacent to the large diameter portion and is located closer to the tip end than the base end, as defined in the present invention.

[0066] In the first embodiment, as shown in FIG. 6, the outer periphery of the end face of the tip portion 68 of the pipe joint 62 is rounded, but the shape of the tip portion 68 of the pipe joint 62 is not limited to this.

[0067] FIG. 10 is a cross-sectional view of a modified pipe joint 62 used in the metal foil attachment process.

[0068] As shown in Figure 10, the outer periphery of the end face of the tip portion 68 of the pipe fitting 62 may not be rounded, but may have a right-angled shape in cross section. Such a shape can be formed by plastic working. The pipe fitting 62 may be manufactured by plastic working. It may also be manufactured by pipe expansion processing.

[0069] In addition, in embodiment 1, as shown in Figure 9, the inner surface of the metal foil 70 is located closer to the inside of the through hole 37 than the inner wall of the through hole 37 of the clad material 31, but the position of the metal foil 70 is not limited to this.

[0070] FIG. 11 is an enlarged cross-sectional view of a part of a modified example of the reinforcing plate 31 and the metal foil 70 brazed in the brazing process.

[0071] 11 , it is preferable that the positions of the inner peripheral surface of the metal foil 70 and the inner wall surface of the through hole 37 of the clad material 31 are aligned in the radial direction of the through hole 37. This is because, with such positions, brazing material can be supplied evenly from both the metal foil 70 and the clad material 31 to the gap between the inner wall of the through hole 33 of the reinforcing plate 31 and the base end 66 of the pipe fitting 62 during the brazing process.

[0072] (Embodiment 2) In the manufacturing method of the plate heat exchanger 1A according to embodiment 1, the outward-facing surfaces, i.e., outer surfaces, of the reinforcing plates 30A, 40A included in the plate heat exchanger 1A to be manufactured are flat. However, the reinforcing plates 30A, 40A are not limited to this. The reinforcing plates 30A, 40A only need to have through holes 33 for allowing fluid to flow in and out of the flow passage spaces of the heat transfer plates 10, 20, and clad materials 31, 41, i.e., clad layers, formed on the inner surfaces by brazing. The outer surfaces of the reinforcing plates 30A, 40A may have any shape as long as this requirement is satisfied. For example, the outer surfaces of the reinforcing plates 30A, 40A may have recesses into which excess brazing fills during the brazing process.

[0073] In the manufacturing method of the plate heat exchanger 1B according to the second embodiment, a reinforcing plate 30B is used, the outer surface of which is formed with a recess 36 surrounding the through-hole 33. Hereinafter, the manufacturing method of the plate heat exchanger 1B according to the second embodiment will be described with reference to Figures 12 and 13. In the second embodiment, the configuration different from the first embodiment will be mainly described.

[0074] Fig. 12 is a perspective view of a reinforcing plate 30B and a pipe joint 62 included in a plate heat exchanger 1B according to embodiment 2. Fig. 13 is an enlarged cross-sectional view of a portion of the reinforcing plate 30B to which a pipe joint 62 has been attached by a pipe joint attaching step included in the manufacturing method of the plate heat exchanger 1B.

[0075] As shown in Figures 12 and 13, in the plate heat exchanger 1B to be manufactured, a recess 36 in the shape of a circular groove surrounding the through hole 33 is formed on the outer surface side of the reinforcing plate 30B, i.e., on the -X surface side.

[0076] As shown in FIG. 13 , the recess 36 has a rectangular cross-sectional shape, recessed from the −X surface of the reinforcing plate 30B in the +X direction. As shown in FIG. 12 , the recess 36 extends in an annular shape as described above. The annular shape is concentric with the circular opening of the through-hole 33. The diameter D6 of the annular shape is larger than the inner diameter D4 of the metal foil 70 and smaller than the outer diameter D5 of the metal foil 70. As a result, when the metal foil 70 is sandwiched between the bead portion 65 of the pipe fitting 62 and the reinforcing plate 30B in the pipe fitting attachment step included in the manufacturing method of the plate-type heat exchanger 1B, the recess 36 is covered by the metal foil 70, as shown in FIG. 13 . That is, the recess 36 is located on the +X side of the metal foil 70. As a result, when the metal foil 70 is melted in the brazing step included in the manufacturing method of the plate-type heat exchanger 1B, the brazing filler metal can penetrate. This allows the recess 36 to collect excess brazing filler metal from the brazing step. As a result, the recess 36 prevents the brazing filler metal from spreading toward the bead portion 65 and reaching the tip portion 68 of the pipe fitting 62 on the −X side beyond the bead portion 65 .

[0077] The recess 36 is located on the +X side of the metal foil 70, and the position of the recess 36 is preferably on the +X side of the tip of the bead portion 65 of the pipe fitting 62. Alternatively, the recess 36 is preferably provided at a position facing the flat portion 654, which is the +X surface of the bead portion 65. This is because excess brazing filler metal is likely to accumulate in these positions during the brazing process.

[0078] The method for manufacturing the plate heat exchanger 1B is the same as the method for manufacturing the plate heat exchanger 1A according to embodiment 1, except that the recesses 36 are formed in the reinforcing plates 30B. Therefore, detailed description thereof will be omitted.

[0079] As described above, in the manufacturing method for the plate-type heat exchanger 1B according to the second embodiment, the reinforcing plate 30B has a recess 36 on its outer surface surrounding the through hole 33. Therefore, excess brazing filler metal is collected in the recess 36 during the brazing process, preventing the excess brazing filler metal from spreading beyond the brazing point. For example, the excess brazing filler metal is prevented from reaching the tip 68 of the pipe fitting 62. Although an O-ring is attached to the tip 68 of the pipe fitting 62, the excess brazing filler metal does not adhere to the tip 68 of the pipe fitting 62. Therefore, the manufacturing method for the plate-type heat exchanger 1B can improve the adhesion of the O-ring. As a result, the airtightness and watertightness of the pipe fitting 62 can be improved.

[0080] The manufacturing method of the plate heat exchangers 1A, 1B and the plate heat exchangers 1A, 1B according to the first and second embodiments of the present disclosure have been described above. However, the manufacturing method of the plate heat exchangers 1A, 1B and the plate heat exchangers 1A, 1B are not limited to this.

[0081] For example, in the first and second embodiments, the inner diameter D4 of the metal foil 70 is larger than the outer diameter D1 of the base end 66 of the pipe fitting 62 by a small distance, and the outer diameter D5 of the metal foil 70 is larger than the outer diameter D2 of the bead portion 65 of the pipe fitting 62. However, the inner diameter D4 and the outer diameter D5 of the metal foil 70 are not limited to these. The metal foil 70 may be any brazing material that can be disposed on the outer surface of the reinforcing plate 30A, 30B, or 40A and around the through holes 32, 33, 42, or 43. Therefore, the inner diameter D4 and the outer diameter D5 of the metal foil 70 are arbitrary as long as they satisfy this condition. The same is true for the thickness T2 of the metal foil 70.

[0082] For example, the inner diameter D4 of the metal foil 70 may be the same as the outer diameter D1 of the base end 66 of the pipe fitting 62. On the other hand, the outer diameter D5 of the metal foil 70 may be the same as the outer diameter D2 of the bead portion 65 of the pipe fitting 62, although this does not prevent the metal foil 70 from being left unattached during manufacturing. Alternatively, the outer diameter D5 may be smaller than the outer diameter D2 of the bead portion 65.

[0083] Furthermore, in the first and second embodiments, the metal foil 70 has a circular and flat shape. However, the shape of the metal foil 70 is not limited to this. As described above, the metal foil 70 may be any brazing material that can be placed on the outer surface of the reinforcing plate 30A, 30B, 40A and around the through holes 32, 33, 42, 43. Therefore, the metal foil 70 may be replaced with a brazing material that satisfies this condition.

[0084] Fig. 14 is a cross-sectional view of a rod-shaped brazing filler metal 71 and a pipe joint 62 used in a modified example of the manufacturing method for the plate heat exchanger 1A according to embodiment 1. Fig. 15 is a cross-sectional view of a paste-like brazing filler metal 72 and a pipe joint 62 used in another modified example of the manufacturing method for the plate heat exchanger 1A according to embodiment 1.

[0085] As shown in FIG. 14 , the pipe fitting 62 may have a cylindrical large-diameter portion 651 whose inner and outer diameters are larger than those of the base end 66 and which cannot be inserted into the through-hole 33 of the reinforcing plate 30A. A recess 652 may be formed in a corner of the large-diameter portion 651 on the base end 66 side. In this case, a brazing filler metal 71 that can be fitted into the recess 652 may be used instead of the metal foil 70 in the brazing step of the manufacturing method of the plate-type heat exchanger 1A. The brazing filler metal 71 may be a rod-shaped brazing filler metal 71 that is bent into a ring shape and has a circular cross section. This is because a brazing filler metal 71 with such a shape can be positioned by the recess 652. Furthermore, this is because a brazing filler metal 71 with such a shape can be supplied to the gap between the base end 66 of the pipe fitting 62 and the inner wall of the through-hole 33 from the side of the reinforcing plate 30A opposite to the side where the clad material 31 is located, i.e., from the −X side of the reinforcing plate 30A. The brazing material 71 may have a cross-sectional shape that is rectangular, elliptical, or the like, in addition to a circular cross-sectional shape.

[0086] 15, the pipe fitting 62 may have an enlarged diameter portion 651 that does not have a recess 652 at the corner portion on the base end 66 side. In this case, a paste-like brazing material 72 may be placed along the corner portion on the base end 66 side of the enlarged diameter portion 651 in the brazing step of the manufacturing method of the plate-type heat exchanger 1A. This is because, with this type of brazing material 72, the brazing material can be supplied to the gap between the base end 66 of the pipe fitting 62 and the inner wall of the through hole 33 from the -X surface side of the reinforcing plate 30A, as in the embodiment shown in FIG.

[0087] In the case of the pipe joint 62 shown in FIG. 15, the paste-like brazing material 72 may be replaced with the metal foil 70 described in the first and second embodiments.

[0088] Furthermore, in order to supply a sufficient amount of brazing filler metal to the gap between the base end 66 of the pipe fitting 62 and the inner wall of the through hole 33, the volume of the brazing filler metals 71, 72 is preferably 25% or more of the volume of the gap between the base end 66 of the pipe fitting 62 and the inner wall of the through hole 33. The metal foil 70 described in the first and second embodiments also preferably has a similar volume.

[0089] In the first and second embodiments, the pipe joint attachment step is performed after the metal foil attachment step. However, the manufacturing method for the plate heat exchangers 1A and 1B is not limited to this. The manufacturing method for the plate heat exchangers 1A and 1B may include the following steps: (1) placing brazing filler metal on the outer surface of the outermost heat transfer plate and around the through holes 32, 33, 42, and 43; and (2) inserting the base ends of the tube members into the through holes 32, 33, 42, and 43 from the outer surface of the outermost heat transfer plate and aligning the large-diameter portions of the tube members adjacent to the outer surface of the outermost heat transfer plate, thereby attaching the tube members to the outermost heat transfer plate. In the manufacturing method for the plate heat exchangers 1A and 1B, the step (2) may be performed after the step (1), or conversely, the step (1) may be performed after the step (2).

[0090] Here, the outermost heat transfer plate refers to the outermost plate among the plates generally referred to as heat transfer plates, which include the reinforcing plates 30A, 30B, and 40A and the heat transfer plates 10 and 20. Furthermore, the tubular member refers to a tubular member, and one example thereof is the pipe joints 61-64.

[0091] Therefore, as long as the above conditions are satisfied, there is no limitation on the order of the metal foil attaching step and the pipe joint attaching step described in the first and second embodiments. For example, when the brazing filler metal 72 shown in Fig. 15 is used, the metal foil attaching step, i.e., the step of placing the brazing filler metal 72, may be performed after the pipe joint attaching step.

[0092] In the first and second embodiments, the material of the metal foil 70 is pure copper or a copper alloy. However, the material of the metal foil 70 is not limited as long as it is brazing. For example, the material of the metal foil 70 may be pure aluminum or an aluminum alloy.

[0093] In the first and second embodiments, the pipe joints 61-64 are joined to the reinforcing plates 30A, 30B, and 40A. However, the manufacturing method of the plate heat exchanger 1A is not limited to this. The pipe joints 61-64 may be any pipe members that allow fluid to flow in and out of the flow path space. For example, the pipe joints 61-64 may be connecting pipes, refrigerant pipes, nozzles, or the like used to connect to external devices.

[0094] In addition, in the first and second embodiments, the pipe fittings 61-64 are manufactured by processing the ends of pipes. As a result, the pipe wall thickness of the pipe fittings 61-64 is constant. However, the pipe fittings 61-64 are not limited to this. As described above, the pipe fittings 61-64 may be any pipe member that allows fluid to flow in and out of the flow path space, so the thickness of the pipe wall does not need to be constant.

[0095] FIG. 16 is a cross-sectional view of yet another modified example of the pipe joint 62 included in the plate heat exchanger 1A according to the first embodiment.

[0096] As a result of being manufactured by cutting, the pipe fitting 62 may have a pipe wall thickness at the tip end portion 68 and the bead portion 65 that is thicker than the pipe wall thickness at the base end portion 66, as shown in Fig. 16. In this way, the pipe fitting 62 may have a portion of the pipe wall that is thicker than the other portions of the pipe wall.

[0097] Furthermore, in the first and second embodiments, the pipe fittings 61-64 are temporarily fixed to the reinforcing plates 30A, 30B, and 40A by crimping the base ends 66 of the pipe fittings 61-64. However, the manufacturing method for the plate heat exchangers 1A and 1B is not limited to this. In the manufacturing method for the plate heat exchangers 1A and 1B, the step of attaching the pipe fittings 61-64 to the reinforcing plates 30A, 30B, and 40A, in other words, the step of attaching the pipe members to the outermost heat transfer plates, may be performed by inserting the base ends of the pipe members into the through holes 32, 33, 42, and 43 from the outer surface side of the outermost heat transfer plate and aligning the bead portion 65 or the large diameter portion 651 adjacent to the outer surface of the outermost heat transfer plate.

[0098] Here, the bead portion 65 or the large diameter portion 651 being adjacent to the outer surface of the outermost heat transfer plate may include the bead portion 65 or the large diameter portion 651 being adjacent to the outer surface of the outermost heat transfer plate via a brazing material, that is, the metal foil 70 or the brazing materials 71 and 72. Alternatively, it may include the bead portion 65 or the large diameter portion 651 being adjacent to the outer surface of the outermost heat transfer plate without the metal foil 70 or the brazing materials 71 and 72 being interposed therebetween.

[0099] Therefore, in the manufacturing method of the plate-type heat exchangers 1A and 1B, whether or not to crimp the base ends 66 of the pipe fittings 61-64 is an optional step. For example, the pipe fittings 61-64 may be temporarily fixed to the reinforcing plates 30A, 30B, and 40A by press-fitting the base ends 66 of the pipe fittings 61-64 into the through-holes 33 of the reinforcing plates 30A, 30B, and 40A.

[0100] In the first and second embodiments, pipe fittings 61 and 62 are connected to a reinforcing plate 30A to which a clad material 31 having the same shape as the reinforcing plate 30A is attached. Furthermore, pipe fittings 63 and 64 are connected to a reinforcing plate 40A to which a clad material 41 having the same shape as the reinforcing plate 40A is attached. However, the reinforcing plates 30A and 40A are not limited to this. In the manufacturing method of the plate-type heat exchangers 1A and 1B, it is sufficient that the outermost heat transfer plate has through holes 32, 33, 42, and 43 for allowing fluid to flow in and out of the flow passage space, and that a brazing material is formed around and on the inner surface of the through holes 32, 33, 42, and 43. Therefore, the clad materials 31 and 41 do not need to have the same shape as the reinforcing plates 30A and 40A. For example, the clad materials 31 and 41 may be replaced with ring-shaped metal foils formed around and on the inner surface of the through holes 32, 33, 42, and 43. Furthermore, the clad materials 31, 41 do not have to be attached to the reinforcing plates 30A, 40A in advance and integrated with them, but may be separate components from the reinforcing plates 30A, 40A. In this case, the pipe joints 61-64 may be attached to the reinforcing plates 30A, 40A on which the clad materials 31, 41 are superimposed.

[0101] As described above, the plate heat exchangers 1A, 1B and the manufacturing method thereof are not limited to the above-described embodiment, and various modifications and substitutions can be made. Various embodiments of the present disclosure are described below as appendices.

[0102] (Supplementary Note 1) A method for manufacturing a plate-type heat exchanger comprising: a plurality of heat transfer plates stacked with flow path spaces provided therebetween for a fluid to flow through, wherein at least the outermost heat transfer plate located on the outermost side has through holes for allowing the fluid to flow in and out of the flow path spaces, and a first brazing filler metal around the through holes and on the inner surface side; and a tube member for allowing the fluid to flow in and out of the flow path spaces, the tube member having a base end and a large diameter portion having an outer diameter larger than that of the base end, the base end being passed through the through hole and brazed to the inner wall of the through hole with the large diameter portion adjacent to the outer surface of the outermost heat transfer plate, the method comprising: a step of arranging a second brazing filler metal on the outer surface side of the outermost heat transfer plate and around the through hole; and a step of attaching the tube member to the outermost heat transfer plate by inserting the base end of the tube member into the through hole from the outer surface side of the outermost heat transfer plate and bringing the large diameter portion adjacent to the outer surface of the outermost heat transfer plate. and a step of heating the outermost heat transfer plate to which the tube members are attached, thereby melting the first brazing filler metal and the second brazing filler metal, and brazing the base ends of the tube members to the inner walls of the through holes in the outermost heat transfer plate. (Appendix 2) A method for manufacturing a plate heat exchanger according to Appendix 1, wherein the second brazing filler metal has a ring shape into which the base ends of the tube members can be inserted. (Appendix 3) A method for manufacturing a plate heat exchanger according to Appendix 2, wherein in the step of arranging the second brazing filler metal, the base ends of the tube members are passed through the hole in the ring of the second brazing filler metal before the step of attaching the tube members to the outermost heat transfer plate, and then, in the step of attaching the tube members to the outermost heat transfer plate, the second brazing filler metal is arranged around the through holes by inserting the base ends of the tube members into the through holes until the second brazing filler metal is sandwiched between the large diameter portions of the tube members and the outermost heat transfer plate. (Supplementary Note 4) The method for manufacturing a plate heat exchanger according to Supplementary Note 3, wherein the second brazing filler metal has a foil shape, and in the step of arranging the second brazing filler metal, the second brazing filler metal is sandwiched between the large diameter portion of the tube member and the outermost heat transfer plate, thereby determining the position of the large diameter portion with respect to the outermost heat transfer plate.(Appendix 5) The method for manufacturing a plate heat exchanger according to any one of Appendices 2 to 4, wherein the outer diameter of the second brazing filler metal is larger than the outer diameter of the large diameter portion of the tube member, and the inner diameter of the second brazing filler metal is smaller than the outer diameter of the large diameter portion of the tube member and larger than the outer diameter of the base end of the tube member. (Appendix 6) The method for manufacturing a plate heat exchanger according to any one of Appendices 1 to 4, wherein the first brazing filler metal is a cladding layer formed by brazing and provided on the inner surface side of the outermost heat transfer plate. (Appendix 7) The method for manufacturing a plate heat exchanger according to any one of Appendices 1 to 6, wherein the large diameter portion of the tube member has an outer diameter larger than any of the portions from the base end to the tip end. (Appendix 8) The method for manufacturing a plate heat exchanger according to any one of Appendices 1 to 7, wherein the thickness of the large diameter portion of the tube member in the extension direction of the tube member is larger than the thickness of the second brazing filler metal. (Supplementary Note 9) The method for manufacturing a plate heat exchanger according to any one of Supplementary Notes 1 to 8, wherein the outermost heat transfer plate has a recess provided on an outer surface thereof and surrounding the through hole, and in the step of arranging the second brazing filler metal, the second brazing filler metal is arranged on the recess. (Supplementary Note 10) The method for manufacturing a plate heat exchanger according to any one of Supplementary Notes 1 to 9, wherein the tubular member has a pipe portion adjacent to the large diameter portion and located closer to the tip end than the base end, and the pipe portion has lower wettability with respect to the brazing filler metal obtained by melting the first brazing filler metal and the second brazing filler metal than the large diameter portion.(Supplementary Note 11) A plate type heat exchanger comprising: a plurality of heat transfer plates stacked with flow path spaces formed therebetween, through which a fluid flows, the outermost heat transfer plate located on the outermost side having through holes for allowing the fluid to flow in and out of the flow path spaces, and a first brazing filler metal provided around the through holes and on the inner surface side; a tube member for allowing the fluid to flow in and out of the flow path spaces, the tube member having a base end and a large diameter portion provided on the tip side of the base end, the large diameter portion having an outer diameter larger than that of the base end, the base end being passed through the through hole and brazed to the inner wall of the through hole with the large diameter portion adjacent to the outer surface of the outermost heat transfer plate; and a second brazing filler metal on the outer surface side of the outermost heat transfer plate and around the through hole, wherein brazing filler is filled between the outermost heat transfer plate and the large diameter portion of the tube member, and between the inner wall of the through hole and the base end of the tube member.

[0103] The present disclosure allows various embodiments and modifications without departing from the broad spirit and scope of the present disclosure. Furthermore, the above-described embodiments are intended to explain the present disclosure and do not limit the scope of the present disclosure. That is, the scope of the present disclosure is defined by the claims, not the embodiments. Various modifications made within the scope of the claims and within the meaning of the disclosure equivalent thereto are considered to be within the scope of the present disclosure.

[0104] This application is based on Japanese Patent Application No. 2022-204852 filed on December 21, 2022. The entire specification, claims, and drawings of Japanese Patent Application No. 2022-204852 are incorporated herein by reference.

[0105] 1A, 1B Plate type heat exchanger, 10 Heat transfer plate, 11 Upright wall, 12 Inner fin, 13 Metal foil, 14, 15 Inlet / outlet holes, 16, 17 Communication holes, 20 Heat transfer plate, 21 Upright wall, 22 Inner fin, 23 Metal foil, 24, 25 Communication holes, 26, 27 Inlet / outlet holes, 30A, 30B Reinforcement plate, 31 Clad material, 32, 33 Through hole, 34, 35 Fillet, 36 Depression, 37 Through hole, 40A Reinforcement plate, 41 Clad material, 42, 43 Through hole, 50 Laminate, 61-64 Pipe joint, 65 Bead portion, 66 Base end portion, 67 Groove, 68 Tip portion, 70 Metal foil, 71, 72 Brazing material, 80 Punch, 651 Large diameter portion, 652 recessed portion, 653, 654 flat portion, 655, 656 straight pipe portion, A1-A3 arrow, D1-D3 outer diameter, D4 inner diameter, D5 outer diameter, D6 diameter, G gap, T1, T2 thickness.

Claims

1. a plurality of heat transfer plates stacked with flow passage spaces between them through which a fluid flows, at least an outermost heat transfer plate positioned on the outermost side has a through hole for allowing the fluid to flow in and out of the flow passage space, and has a first brazing material around the through hole and on an inner surface side of the heat transfer plate; a pipe member for allowing the fluid to flow in and out of the flow path space, the pipe member having a base end and a large diameter portion having an outer diameter larger than that of the base end, the base end being passed through the through hole and brazed to an inner wall of the through hole with the large diameter portion adjacent to an outer surface of the outermost heat transfer plate; A method for manufacturing a plate heat exchanger comprising: disposing a second brazing material on an outer surface of the outermost heat transfer plate and around the through hole; a step of attaching the tube member to the outermost heat transfer plate by inserting the base end of the tube member into the through hole from the side of the outer surface of the outermost heat transfer plate and aligning the large diameter portion adjacent to the outer surface of the outermost heat transfer plate; a step of heating the outermost heat transfer plate to which the tube member is attached, thereby melting the first brazing material and the second brazing material to braze the base end of the tube member to an inner wall of the through hole of the outermost heat transfer plate; A method for manufacturing a plate heat exchanger comprising:

2. The outer shape of the second brazing material when viewed from the axial direction of the tube member is larger than the outer shape of the base end of the tube member and smaller than the outer shape of the outermost heat transfer plate when viewed from the axial direction of the tube member. A method for manufacturing the plate heat exchanger according to claim 1.

3. In the step of arranging the second brazing material, the second brazing material is arranged in a ring shape on the outer surface side of the outermost heat transfer plate and around the through hole. A method for manufacturing the plate heat exchanger according to claim 1 or 2.

4. The inner diameter of the second brazing material is larger than the diameter of the through hole in a state before being melted in the brazing process. A method for manufacturing the plate heat exchanger according to claim 1 or 2.

5. The outer diameter of the second brazing material is larger than the outer diameter of the large diameter portion of the tubular member. A method for manufacturing the plate heat exchanger according to claim 1 or 2.

6. The step of attaching the tube member to the outermost heat transfer plate includes a step of crimping the base end of the tube member while the base end is inserted into the through hole to attach the tube member to the outermost heat transfer plate. A method for manufacturing the plate heat exchanger according to claim 1 or 2.

7. The first brazing material has a second through hole into which the base end of the tube member is inserted during a process of attaching the tube member to the outermost heat transfer plate, The inner diameter of the second through hole at the stage of the process of attaching the tube member to the outermost heat transfer plate is larger than the outer diameter of the base end portion after crimping. A method for manufacturing the plate heat exchanger according to claim 6.

8. The method further comprises the steps of stacking the plurality of heat transfer plates with the flow path spaces therebetween through which a fluid flows, thereby forming a stack, attaching the outermost heat transfer plate having the tubular member attached thereto to the stack thus formed, and pressurizing the stack with the outermost heat transfer plate attached; a step of attaching the tube member to the outermost heat transfer plate by crimping the base end portion before the step of pressing the stack to which the outermost heat transfer plate is attached; A method for manufacturing the plate heat exchanger according to claim 6.

9. The method further comprises the step of manufacturing the tube member by plastic processing. A method for manufacturing the plate heat exchanger according to claim 1 or 2.

10. The method further comprises the step of forming the large diameter portion of the pipe member by crushing a straight pipe in a pipe axial direction. A method for manufacturing the plate heat exchanger according to claim 1 or 2.

11. In the step of brazing the base end of the tube member to the inner wall of the through hole of the outermost heat transfer plate, brazing is performed without using flux. A method for manufacturing the plate heat exchanger according to claim 1 or 2.

12. the second brazing material has a ring shape into which the proximal end of the tubular member can be inserted; A method for manufacturing the plate heat exchanger according to claim 1 or 2.

13. In the step of arranging the second brazing material, before the step of attaching the tube member to the outermost heat transfer plate, the base end of the tube member is passed through a hole in the ring of the second brazing material, and then, in the step of attaching the tube member to the outermost heat transfer plate, the base end of the tube member is inserted into the through hole until the second brazing material is sandwiched between the large diameter portion of the tube member and the outermost heat transfer plate, thereby arranging the second brazing material around the through hole. A method for producing the plate heat exchanger according to claim 12.

14. The second brazing material has a foil shape, In the step of arranging the second brazing filler metal, the second brazing filler metal is sandwiched between the large diameter portion of the tube member and the outermost heat transfer plate, thereby determining a position of the large diameter portion with respect to the outermost heat transfer plate. A method for producing the plate heat exchanger according to claim 13.

15. an outer diameter of the second brazing material is larger than an outer diameter of the large diameter portion of the tubular member; an inner diameter of the second brazing material is smaller than an outer diameter of the large diameter portion of the tubular member and is larger than an outer diameter of the base end portion of the tubular member; A method for producing the plate heat exchanger according to claim 12.

16. The first brazing material is a clad layer formed of brazing material on the inner surface side of the outermost heat transfer plate. A method for manufacturing the plate heat exchanger according to claim 1 or 2.

17. The large diameter portion of the tubular member has an outer diameter larger than any of the portions from the base end portion to the tip end portion. A method for manufacturing the plate heat exchanger according to claim 1 or 2.

18. a thickness of the large diameter portion of the tubular member in an extension direction of the tubular member is greater than a thickness of the second brazing filler metal; A method for manufacturing the plate heat exchanger according to claim 1 or 2.

19. The outermost heat transfer plate is provided on an outer surface side and has a recess surrounding the through hole, In the step of disposing the second brazing material, the second brazing material is disposed on the recess. A method for manufacturing the plate heat exchanger according to claim 1 or 2.

20. the tubular member has a tubular portion adjacent to the large diameter portion and located distally of the base end portion, the pipe portion has a lower wettability with respect to a brazing filler metal obtained by melting the first brazing filler metal and the second brazing filler metal than the large diameter portion; A method for manufacturing the plate heat exchanger according to claim 1 or 2.

21. a plurality of heat transfer plates stacked with flow passage spaces between them through which a fluid flows, the outermost heat transfer plate positioned on the outermost side having a through hole for allowing the fluid to flow in and out of the flow passage space, and a first brazing material provided around the through hole and on an inner surface side; a pipe member for allowing the fluid to flow in and out of the flow path space, the pipe member having a base end and a large diameter portion provided on a tip side of the base end and having an outer diameter larger than that of the base end, the base end being passed through the through hole and brazed to an inner wall of the through hole with the large diameter portion adjacent to an outer surface of the outermost heat transfer plate; a second brazing material on the outer surface side of the outermost heat transfer plate and around the through hole; Equipped with a brazing material is filled between the outermost heat transfer plate and the large diameter portion of the tube member, and between an inner wall of the through hole and the base end portion of the tube member; Plate heat exchanger.

22. In the tubular member, the thickness of the base end portion and the large diameter portion are the same due to terminal processing.

22. The plate heat exchanger according to claim 21.

23. The pipe member has a straight pipe portion provided on the side of the large diameter portion opposite to the side where the base end portion is adjacent to the large diameter portion, In the pipe member, the straight pipe portion and the large diameter portion have the same thickness due to plastic processing.

22. The plate heat exchanger according to claim 21.

24. The large diameter portion has a flange shape formed in the shape of a flat plate protruding radially from the base end portion.

23. A plate heat exchanger according to claim 21 or 22.

25. The pipe member has a straight pipe portion provided on the side of the large diameter portion opposite to the side adjacent to the base end portion, and a tip portion adjacent to the straight pipe portion and having a groove formed on an outer periphery, The surface roughness of the straight pipe portion is smaller than the surface roughness of the tip portion.

23. A plate heat exchanger according to claim 21 or 22.

26. The wettability of the straight pipe portion with respect to the molten solder is lower than the wettability of the inner wall of the groove with respect to the molten solder.

26. The plate heat exchanger according to claim 25.

27. ​​The tubular member is formed of stainless steel.

26. The plate heat exchanger according to claim 25.

28. The tubular member further has a tip end having an outer diameter larger than the outer diameter of the base end.

23. A plate heat exchanger according to claim 21 or 22.

29. The second brazing material is formed of pure copper or a copper alloy.

23. A plate heat exchanger according to claim 21 or 22.