Manufacturing method of plate type heat exchanger

Abstract

To provide a manufacturing method of a plate type heat exchanger, not causing excessive compression during a lamination compression step, and capable of reducing a clearance of a sealing part, and reducing a possibility of brazing defect between heat transfer plates, and leakage.SOLUTION: A manufacturing method of a plate type heat exchanger is for manufacturing the plate type heat exchanger in which wavy irregularities are formed in a central part, heat transfer plates formed with flange portions extending to the outside from a sealing part of a peripheral part are laminated, and an internal space between the adjacent heat transfer plates is alternately used as a low-temperature side flow passage and a high-temperature side flow passage in a lamination direction. A rod brazing is disposed between the flange portions to be set vertically in the lamination direction of the heat transfer plate, the laminated heat transfer plates come in contact with each other in an apex of the irregularities in the central part, and brazing is performed in a state of disposing the rod brazing so that a distance in the lamination direction between the flange portions to be set vertically in the lamination direction of the heat transfer plate becomes constant due to the existence of the rod brazing.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] One conventional manufacturing process for plate heat exchangers is as follows: Heat transfer plates are stacked (layered) with foil brazing sandwiched between them, and while stacked with the foil brazing sandwiched between them, a load is applied in the direction of adhesion to caulk, and compressive loads are applied above and below using weights, while the whole is heated in a furnace to melt the foil brazing and form a brazing joint.

[0003] Patent Document 1 discloses a plate-type heat exchanger characterized in that a heat transfer plate is formed into a dish shape by pressing a steel plate to form an outer edge portion with a small inclination angle at the upper edge of a side edge portion that is raised on the periphery, and a brazing rod is inserted into an opening groove formed between the upper and lower outer edges of the stacked heat transfer plates to perform brazing and joining. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-180077 Summary of the Invention [Problem to be solved by the invention]

[0005] In a structure in which foil brazing filler metal extends to the sealing portion raised to the periphery and is sandwiched between heat transfer plates, the gap between the heat transfer plates before brazing can vary by several times the thickness of the foil brazing filler metal, depending on the inclination angle of the upper edge of the side edge raised to the periphery. Using a method such as that described in Patent Document 1, in which the foil brazing filler metal between the sealing portions is removed and a solder rod is placed at the end of the sealing portion, reduces the gap between the heat transfer plate sealing portions, thereby reducing the gap between the heat transfer plates and improving the accuracy of the brazing joint. However, even with a structure such as that described in Patent Document 1, the heat transfer plates are stacked and pressed naturally without a stopper in the contact direction, which can lead to uneven or misaligned contact between the heat transfer plates, potentially resulting in poor brazing joints and leaks between the heat transfer plates. While applying a large compressive load, such as stacking pressure before brazing, to improve adhesion is sometimes proposed, applying a large compressive load during brazing is difficult.

[0006] The present disclosure has been made to solve the above-mentioned problems, and an object of the present disclosure is to provide a method for manufacturing a plate heat exchanger that does not cause excessive compression in the stacking and pressurizing process, can reduce gaps in sealing portions, and reduces the possibility of poor brazing and leaks between heat transfer plates. [Means for solving the problem]

[0007] The method for manufacturing a plate-type heat exchanger according to the present disclosure is a method for manufacturing a plate-type heat exchanger in which heat transfer plates each having a wavy unevenness formed in the center and a flange formed that extends outward beyond the sealing portion on the periphery are stacked, and the internal spaces between adjacent heat transfer plates are used alternately in the stacking direction as a low-temperature side flow path and a high-temperature side flow path, and brazing rods are provided between the upper and lower flanges in the stacking direction of the heat transfer plates, and the stacked heat transfer plates are brazed with the brazing rods arranged so that they come into contact with each other at the tops of the unevenness in the center and the distance in the stacking direction between the upper and lower flanges in the stacking direction of the heat transfer plates is constant due to the presence of the brazing rods. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to provide a method for manufacturing a plate heat exchanger that does not cause excessive compression in the stacking and pressurizing process, can reduce gaps in the sealing portions, and can reduce the possibility of poor brazing and leaks between heat transfer plates. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a circuit diagram showing an example in which the plate heat exchanger according to the first embodiment is used as a hot water supply device having a bathtub reheating function. FIG. [Figure 2] 1 is a perspective view showing the appearance of a plate heat exchanger according to a first embodiment. [Figure 3] FIG. 3 is a development view of the plate heat exchanger shown in FIG. 2. [Figure 4] 4 is a cross-sectional end view taken along line II in the stacked state of FIG. 3. FIG. [Figure 5] FIG. 3 is a development view of the pair layers of the plate heat exchanger of FIG. 2. [Figure 6] 6 is a cross-sectional end view in a stacked state corresponding to the view taken along the line AA in FIG. 5. FIG. [Figure 7] 6 is a cross-sectional end view of a structure not provided with foil brazing, taken along the line AA in FIG. 5. FIG. [Figure 8] 6 is a cross-sectional view of the case where biased application occurs as viewed from the arrow AA in FIG. 5. FIG. [Figure 9] FIG. 3 is a cross-sectional view of the plate heat exchanger shown in FIG. 2. [Figure 10] FIG. 2 is a diagram showing a main part of the plate heat exchanger according to the first embodiment, and is a cross-sectional end view in which the brazing foil is removed and the brazing rod is arranged. [Figure 11] FIG. 11 is a cross-sectional end view of the brazing rod of FIG. 10, the cross-sectional shape of which is polygonal. [Figure 12] FIG. 10 is a front view of a heat transfer plate in which solder rods are arranged on the entire outer periphery. [Figure 13] FIG. 10 is a front view of a heat transfer plate with a solder rod arranged on a straight line portion. [Figure 14] FIG. 10 is a diagram showing a rod-shaped product with a gripping portion added. [Figure 15] FIG. 11 is a cross-sectional end view of a plate heat exchanger according to a seventh embodiment. [Figure 16] FIG. 10 is a cross-sectional end view showing the contact between the bent portion and the flange portion of the heat transfer plate. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments will be described with reference to the drawings. Common or corresponding elements in each drawing are designated by the same reference numerals, and their description will be simplified or omitted. When angles are mentioned in this disclosure, if there is a reflex angle and a minor angle whose sum is 360 degrees, this generally refers to the minor angle. If there is an acute angle and an obtuse angle whose sum is 180 degrees, this generally refers to the acute angle. The configurations shown in the following embodiments are examples of the technical ideas of this disclosure, and may be combined with other known technologies or multiple technical ideas described in this disclosure. Furthermore, parts of the configuration may be omitted or modified without departing from the spirit of this disclosure.

[0011] Embodiment 1 FIG. 1 is a circuit diagram showing an example in which the plate heat exchanger according to the first embodiment is used as a hot water supply device with a bathtub reheating function. In the diagram, the hot water supply device includes a heat pump circuit 1 and a tank unit 2. The heat pump circuit 1 is configured by connecting a compressor 11, a radiator 12, an expansion valve 13, and an evaporator 14 in this order via pipes 15 and 16. The tank unit 2 is configured by including a hot water storage tank 21 and a plate heat exchanger 300. The hot water storage tank 21 is a stacked hot water storage tank that can store water in separate temperature layers by circulating water stored in the lower part to the heat pump circuit 1 via pipes 23 using a circulation pump 24 and flowing high-temperature water heated by the radiator 12 into the upper part via pipes 22.

[0012] FIG. 2 is a perspective view showing the appearance of a plate heat exchanger 300 according to the first embodiment. The plate heat exchanger 300 according to the first embodiment has an external shape as shown in the perspective view of FIG. 2. A plurality of heat transfer plates 3, each having a corrugated surface 31 formed thereon to increase the heat transfer area, are stacked vertically for use. The plate heat exchanger 300 has a first flow path 301 and a second flow path 302. The first flow path 301 is configured to supply high-temperature water stored in the upper part of the hot water storage tank 21 to an upper high-temperature side inlet 301a via a pipe 25, discharge the high-temperature water from the upper high-temperature side outlet 301b, and return the water to the lower part of the hot water storage tank 21 via a pipe 27 by a circulation pump 26. The second flow path 302 is configured to allow low-temperature water from the bathtub 4 to flow into the lower low-temperature side inlet 302a via a pipe 41 by a circulation pump 42, discharge the water from the upper low-temperature side outlet 302b, and return the water to the bathtub 4 via a pipe 43. In this way, by exchanging heat between the first flow path 301 and the second flow path 302 in the plate-type heat exchanger 300, the bath water in the bathtub 4 can be reheated.

[0013] Fig. 3 is a development of the plate heat exchanger 300 shown in Fig. 2, Fig. 4 is a cross-sectional end view taken along line II in the stacked state of Fig. 3, and Fig. 5 is a development of a pair of layers of the plate heat exchanger of Fig. 2. As shown in Figs. 3 and 4, the heat transfer plate 3 is a substantially rectangular plate with a wavy pattern 31 formed in the central portion constituting the heat transfer surface, and a sealing portion 32 and a flange portion 33 extending outward from the sealing portion 32 formed on the periphery as shown in Fig. 5. The plate heat exchanger 300 maintains watertightness, airtightness, and water pressure resistance by sandwiching a brazing foil 6 between a heat transfer plate 3a and another heat transfer plate 3b, stacking a predetermined number of plates under a predetermined load, and brazing the contact points, including the sealing portions 32, between the heat transfer plates 3a, 3b, ... 3e.

[0014] Fig. 6 is a cross-sectional end view in a stacked state corresponding to the view taken along line AA in Fig. 5. Fig. 7 is a cross-sectional end view in a structure without foil brazing as viewed along line AA in Fig. 5. Fig. 8 is a cross-sectional view in the case where biased application occurs as viewed along line AA in Fig. 5. Fig. 9 is a cross-sectional view of the plate heat exchanger shown in Fig. 2.

[0015] For convenience, the heat transfer plates 3 will be referred to as the first plate 3a, the second plate 3b, the third plate 3c, and the fourth plate 3d in order from bottom to top in FIG. 9, with the topmost heat transfer plate 3 being referred to as the final plate 3e. The plate heat exchanger 300 is formed by repeatedly stacking pairs of first plates 3a and second plates 3b that form a first flow path (here, the high-temperature side flow path) 301. As shown in FIG. 9, any number of pairs are stacked in this order, starting from the bottom, starting with the first pair P1 of the first plate 3a and the second plate 3b, followed by the second pair P2 of the third plate 3c and the fourth plate 3d. The final plate 3e, which does not have a high-temperature side inlet or outlet and is located above the fourth pair P4 in this example, is used as the lowest layer of heat transfer plates. The third pair P3 has the same configuration as the first pair P1, and the stacking direction is also the same.

[0016] The heat transfer plates 3 are formed so that the crests 31a (FIG. 4) of the ridges or the bottoms 31b (FIG. 4) of the grooves that form the wavy irregularities 31 form a V-shape or an inverted V-shape in the center. In the case of the first pair P1, if the upper first plate 3a is V-shaped, the lower second plate 3b is arranged in an inverted V-shape. As a result, the crests 31a of the waves (ridges) of the heat transfer plates 3 that face each other in the first flow path 301 on the high-temperature side intersect and collide with each other, forming a contact point B at the intersection as shown in FIG. 4, thereby forming flow path spaces with a constant interval.

[0017] 9, the stacked heat transfer plates 3 constituting the plate heat exchanger 300 have bent portions 33a only on the flange portions 33 of the lower first plate 3a and third plate 3c of the first pair P1 to fourth pair P4 that form the first flow path 301 on the high-temperature side, i.e., the even-numbered heat transfer plates 3 from top to bottom in the figure. The bent portions 33a are bent at approximately 90 degrees with respect to the flange portion 33.

[0018] As described above, the plate heat exchanger 300 can be obtained by forming a plurality of heat transfer plates 3 (3a, 3b, . . . , 3e) into pairs (P1 to P4) with the brazing foil 6 sandwiched between them, rotating the resulting arrangement by 180°, and stacking them. The brazing foil 6 may have a shape that extends to the sealing portion 32 of the heat transfer plate, as shown in FIG. 6. Below, a more specific description will be given of typical characteristic features of the first embodiment of the present disclosure, which were invented to mitigate brazing joint defects or leak defects that occur during the brazing process.

[0019] As shown in FIG. 6 , the sealing portions 32 are inclined at an angle θ relative to the stacking direction of the heat transfer plates 3. The angle θ is an acute angle. In FIG. 6 , if a brazing foil 6 is sandwiched between the sealing portions 32 of the heat transfer plates 3, the gap dimension between the heat transfer plates 3 before brazing may vary by several times the thickness of the brazing foil depending on the inclination angle of the sealing portions 32. In other words, if the brazing foil 6 is provided, the crests 31 a of the waves (protrusions) of the heat transfer plates 3 may not be in close contact with each other, and the brazing material may not be able to join at the contact points during brazing. Therefore, by using a structure in which the brazing foil 6 is not provided in the sealing portions 32 as shown in FIG. 7 , the sealing portions 32 of the heat transfer plates 3 are in close contact with each other, and contact points B can be created at the intersections of the crests 31 a of the waves (protrusions) of the heat transfer plates 3.

[0020] 8, if a brazing rod 7 is not placed in the space F formed by the flange 33 of the plate-type heat exchanger 300, pressure may be applied to the heat transfer plates 3 in the stacking direction as shown in the figure, resulting in excessive pressure being applied to one side and insufficient pressure being applied to the heat transfer plate 3 on the opposite side. In this case, no contact point B is formed at the intersection between the crests 31a of the waves (protruding stripes) of the heat transfer plates 3, which may result in poor brazing and leaks.

[0021] Fig. 10 is a diagram illustrating the characteristic portion of claim 1, and is a cross-sectional end view in a stacked state corresponding to the view seen from the arrow A-A line in Fig. 5. Fig. 10 is a diagram showing the main parts of the plate-type heat exchanger according to embodiment 1, and is a cross-sectional end view in which the foil brazing material 6 has been removed and a brazing material rod 7 has been placed. In Fig. 10, the brazing material rod 7 is placed in the space F formed by the flange portion 33 of the heat transfer plate 3 and the bent portion 33a provided at the end of the flange portion 33, so that when the upper and lower heat transfer plates 3 are overlapped, the upper and lower flange portions 33 of the heat transfer plate 3 come into contact with the upper and lower brazing material rod 7.

[0022] In FIG. 10 , the brazing filler rods 7 are provided in the space F with dimensions such that contact points B are evenly generated at the intersections of the crests 31 a of the waves (ridges) of the heat transfer plates 3, and have a diameter such that the brazing filler rods 7 come into contact with the flanges 33 of the heat transfer plates 3 when a load is applied. This acts as a stopper, preventing excessive pressure and making it possible to suppress uneven contact between the pair of heat transfer plates 3. As a result, it is possible to suppress poor brazing and leak defects. In this embodiment, brazing filler rods are disposed on every other flange 33 of the heat transfer plates 3, but they may also be disposed between all of the flanges 33. This enables more stable pressure application to the heat transfer plates, improving the reliability of the brazing.

[0023] As described above, the manufacturing method for a plate-type heat exchanger of this embodiment is a manufacturing method for a plate-type heat exchanger in which heat transfer plates 3 each having a wavy asperity 31 formed in the center and flanges 33 extending outward beyond the peripheral sealing portions 32 are stacked, and the internal spaces between adjacent heat transfer plates 3 are alternately used as a low-temperature side flow path and a high-temperature side flow path in the stacking direction, and brazing rods 7 are provided between the upper and lower flanges 33 in the stacking direction of the heat transfer plates 3, and the stacked heat transfer plates 3 are brazed in a state in which the brazing rods 7 are arranged so that the stacked heat transfer plates 3 are in contact with each other at the tops of the central asperity 31 and the distance in the stacking direction between the upper and lower flanges 33 in the stacking direction of the heat transfer plates 3 is constant due to the presence of the brazing rods 7. This prevents excessive compression in the stacking and pressurizing process, makes it possible to reduce gaps in the sealing portions 32, and reduces the possibility of poor brazing and leaks between the heat transfer plates 3.

[0024] Furthermore, in this embodiment, for the reasons mentioned above, when the sealing portion 32 provided on the periphery of the heat transfer plate 3 and the flange portion 33 extending outward from the sealing portion 32 are stacked, it is desirable to place a foil brazing material 6 in the center of the heat transfer plate 3 and not place brazing material between adjacent sealing portions 32.

[0025] Embodiment 2 Next, a second embodiment will be described with reference to Figures 10 and 11. The description will focus on differences from the first embodiment, and common explanations will be simplified or omitted. Elements that are common to or correspond to the elements described above will be denoted by the same reference numerals.

[0026] Fig. 11 is a cross-sectional view showing a main part of a plate heat exchanger according to a second embodiment, in the same stacked state as in Fig. 10. This second embodiment uses a brazing filler rod 7a having a circular cross section as shown in Fig. 10, or a brazing filler rod 7b having a rectangular cross section that is a polygon that fills the space F formed by the flange 33 of the heat transfer plate 3 and the bent portion 33a provided at the end of the flange 33 as shown in Fig. 11. Although not shown, a brazing filler rod 7 having a semicircular cross section may also be used.

[0027] As described above, according to the second embodiment, the amount of brazing filler metal can be increased when the brazing filler metal is melted in the brazing step of the plate heat exchanger 300, thereby improving the accuracy of the brazing. Also, by forming the cross-sectional shape of the brazing filler rods 7b to fill almost the entire area of the space F, the flanges 33 come into contact with the brazing filler rods 7b when a stacking load is applied, and can act as stoppers. This prevents excessive load application, making it possible to suppress uneven adhesion between pairs of heat transfer plates 3.

[0028] Embodiment 3 Next, a third embodiment will be described with reference to Fig. 12. The description will focus on differences from the first embodiment, and common explanations will be simplified or omitted. Elements that are common to or correspond to the elements described above will be denoted by the same reference numerals.

[0029] Fig. 12 is a front view of a single heat transfer plate 3 in which brazing filler rods 7 are arranged around the entire periphery. In the example shown in Fig. 12, by arranging brazing filler rods 7 all around the space F of the heat transfer plate 3, the amount of brazing material can be increased, and many contact points B can be brazed.

[0030] Embodiment 4 Next, a fourth embodiment will be described with reference to Fig. 13. The description will focus on differences from the first embodiment, and common explanations will be simplified or omitted. Elements that are common to or correspond to the elements described above will be denoted by the same reference numerals.

[0031] Fig. 13 is a diagram showing the arrangement of the brazing filler rod 7 in the straight portion of the front view of the heat transfer plate 3 alone. In the example shown in Fig. 13, by arranging the brazing filler rod 7 only in the space F of the straight portion in the longitudinal and lateral directions of the flange portion 33 of the heat transfer plate 3, it is possible to cancel the deflection of the brazing filler rod 7 and more reliably suppress uneven adhesion during the application process of the heat transfer plate 3.

[0032] Embodiment 5. Next, a fifth embodiment will be described with reference to Fig. 14. The description will focus on differences from the first embodiment, and common explanations will be simplified or omitted. Elements that are common to or correspond to the elements described above will be denoted by the same reference numerals.

[0033] FIG. 14 is a diagram in which a gripper 34 is added to the shape of a wax rod. In the example shown in FIG. 14, a gripper 34 for gripping by a robot arm is provided on a part of the wax rod 7 (7a, 7b) having the shape of embodiment 3. The gripper 34 protrudes outward from the center of the wax rod 7 in the longitudinal direction. By using the gripper 34 when automatically lifting and placing the wax rod 7 in the space F of the heat transfer plate 3 using a machine, stable work can be achieved. In other words, providing the gripper 34 on the wax rod 7 makes it easier to transport the wax rod 7 to the space F of the heat transfer plate 3 on an automatic line, enabling stable production.

[0034] Embodiment 6 Next, a sixth embodiment will be described with reference to Fig. 10. The description will focus on differences from the first embodiment, and common explanations will be simplified or omitted. Elements that are common to or correspond to the elements described above will be denoted by the same reference numerals.

[0035] 10, in the plate heat exchanger 300 according to the sixth embodiment, the brazing filler rods 7 are placed in the space F formed by the flanges 33 and the bent portions 33a at the top and bottom in the stacking direction of the heat transfer plates 3. The brazing filler rods 7 are held in the space F by the bent portions 33a and do not roll off to the outside. This more reliably prevents misalignment at the flanges 33 during stacking or pressurization, improving workability.

[0036] Embodiment 7 Next, a seventh embodiment will be described with reference to Fig. 15. The description will focus on differences from the first embodiment, and common explanations will be simplified or omitted. Elements that are common to or correspond to the elements described above will be denoted by the same reference numerals.

[0037] Fig. 15 is a cross-sectional end view of a plate-type heat exchanger 300 according to the seventh embodiment. As shown in Fig. 15, in the plate-type heat exchanger 300 of this embodiment, the brazing filler rods 7 arranged in the stacking direction of the flanges 33 that face each other across the centers of the heat transfer plates 3 have the same height in the stacking direction of the flanges 33. By making the heights of the brazing filler rods 7 arranged in the flanges 33 that face each other across the centers of the heat transfer plates 3 uniform, it is possible to more reliably prevent the application of excessive pressure to one side and insufficient pressure to the heat transfer plate 3 on the opposite side in the stacking direction, as shown in Fig. 8, which may occur spontaneously.

[0038] Embodiment 8 Next, an eighth embodiment will be described with reference to Fig. 16, focusing on differences from the first embodiment described above, and explanations of commonalities will be simplified or omitted. Elements common to or corresponding to the elements described above will be denoted by the same reference numerals.

[0039] FIG. 16 is a cross-sectional end view showing contact between the bent portions 33a and the flanges 33 of the heat transfer plates 3. The example shown in FIG. 16 is characterized in that the bent portions 33a of the heat transfer plates 3 abut against the flanges 33 of the heat transfer plates 3 adjacent in the stacking direction. As in the first embodiment, not only do the brazing rods 7 abut against the flanges 33 of the heat transfer plates 3, but the bent portions 33a also serve to regulate the dimensions of the heat transfer plates 3 in the stacking direction, thereby more reliably preventing misalignment of the heat transfer plates in the stacking direction during the brazing process. That is, when the heat transfer plates 3 are stacked and pressurized, the bent portions 33a of the flanges 33 on the periphery of the heat transfer plates 3 come into contact with the flanges 33 adjacent in the height direction, thereby acting as a stopper in the contact direction. This more reliably prevents uneven contact between the heat transfer plates 3 after stacking and pressurizing, ensures a consistent stacking thickness, and improves brazing accuracy.

[0040] Of the features of the above-described multiple embodiments, two or more features that can be combined may be combined and implemented.

[0041] Various aspects of the present disclosure are summarized below as appendices.

[0042] (Appendix 1) A method for manufacturing a plate heat exchanger in which heat transfer plates each having a wavy concavo-convex shape formed in the center and a flange portion extending outward beyond a sealing portion on the periphery are stacked, and the internal spaces between adjacent heat transfer plates are alternately used as a low-temperature side flow path and a high-temperature side flow path in the stacking direction, A method for manufacturing a plate-type heat exchanger, comprising the steps of: providing a brazing rod between the upper and lower flanges in the stacking direction of the heat transfer plates; and brazing the stacked heat transfer plates in a state in which the brazing rod is arranged so that the stacked heat transfer plates come into contact with each other at the tops of the asperities in the central portions; and maintaining a constant distance in the stacking direction between the upper and lower flanges in the stacking direction of the heat transfer plates due to the presence of the brazing rod. (Appendix 2) 2. The method for manufacturing a plate heat exchanger according to claim 1, wherein when the sealing portions provided in the peripheral portions and the flange portions extending outward from the sealing portions are stacked, a brazing filler metal is placed in the central portion, and no brazing filler metal is placed between adjacent sealing portions. (Appendix 3) 3. The method for manufacturing a plate heat exchanger according to claim 1, wherein the cross-sectional shape of the brazing rod is circular, semicircular, or polygonal. (Appendix 4) 4. The method for manufacturing a plate heat exchanger according to claim 1, wherein the brazing rod is provided on the entire periphery of the space in the flange portion of the heat transfer plate. (Appendix 5) 4. The method for manufacturing a plate heat exchanger according to claim 1, wherein the brazing rod is provided only on linear portions in the longitudinal and lateral directions of the flange portion of the heat transfer plate. (Appendix 6) 6. The method for manufacturing a plate heat exchanger according to any one of claims 1 to 5, wherein the brazing rod is provided with a gripping portion for being gripped by a robot arm. (Appendix 7) a bending portion formed by bending a tip end of the flange portion either upward or downward in the stacking direction, 7. The method for manufacturing a plate heat exchanger according to claim 1, wherein the brazing rod is disposed in a space formed between the flange portions and the bent portions at the upper and lower ends in the stacking direction of the heat transfer plates. (Appendix 8) 8. The method for manufacturing a plate heat exchanger according to claim 1, wherein the brazing rods arranged in the stacking direction of the flanges that face each other across the central portions of the heat transfer plates have the same height in the stacking direction of the flanges. (Appendix 8) 8. The method for manufacturing a plate heat exchanger according to claim 7, wherein an end portion of the flange of the bent portion in the stacking direction abuts against the flange of the heat transfer plate adjacent in the stacking direction. [Explanation of symbols]

[0043] 1 heat pump circuit, 2 tank unit, 3 heat transfer plate, 3a first plate, 3b second plate, 3c third plate, 3d fourth plate, 3e final plate, 4 bathtub, 11 compressor, 12 radiator, 13 expansion valve, 14 evaporator, 15 piping, 16 piping, 21 hot water storage tank, 22 piping, 23 piping, 24 circulation pump, 25 piping, 26 circulation pump, 27 piping, 31 unevenness, 31a top, 31b bottom, 32 sealing portion, 33 flange portion, 33a bent portion, 34 grip portion, 41 piping, 42 circulation pump, 43 piping, 300 plate type heat exchanger, 301 first flow path, 301a High temperature side inlet, 301b high temperature side outlet, 302 second flow path, 302a low temperature side inlet, 302b low temperature side outlet

Claims

1. A method for manufacturing a plate heat exchanger in which heat transfer plates each having a wavy concavo-convex shape formed in the center and a flange portion extending outward beyond a sealing portion on the periphery are stacked, and the internal spaces between adjacent heat transfer plates are alternately used as a low-temperature side flow path and a high-temperature side flow path in the stacking direction, A method for manufacturing a plate-type heat exchanger, comprising the steps of: providing a brazing rod between the upper and lower flanges in the stacking direction of the heat transfer plates; and brazing the stacked heat transfer plates in a state in which the brazing rod is arranged so that the stacked heat transfer plates come into contact with each other at the tops of the asperities in the central portions; and maintaining a constant distance in the stacking direction between the upper and lower flanges in the stacking direction of the heat transfer plates due to the presence of the brazing rod.

2. 2. The method for manufacturing a plate-type heat exchanger according to claim 1, wherein when the sealing portions provided in the peripheral portions and the flange portions extending outward from the sealing portions are stacked, a brazing filler metal is placed in the central portion, and no brazing filler metal is placed between adjacent sealing portions.

3. 3. The method for manufacturing a plate heat exchanger according to claim 1, wherein the cross-sectional shape of the brazing rod is circular, semicircular, or polygonal.

4. 3. The method for manufacturing a plate heat exchanger according to claim 1, wherein the brazing rod is provided around the entire periphery of the space in the flange portion of the heat transfer plate.

5. 3. The method for manufacturing a plate heat exchanger according to claim 1, wherein the brazing rod is provided only on linear portions of the flange of the heat transfer plate in the longitudinal and lateral directions.

6. 3. The method for manufacturing a plate heat exchanger according to claim 1, wherein the brazing rod is provided with a gripping portion for being gripped by a robot arm.

7. a bending portion formed by bending a tip end of the flange portion either upward or downward in the stacking direction, 3. The method for manufacturing a plate heat exchanger according to claim 1, wherein the brazing rod is disposed in a space formed between the flange portions and the bent portions at the upper and lower ends in the stacking direction of the heat transfer plates.

8. 3. The method for manufacturing a plate heat exchanger according to claim 1, wherein the brazing rods arranged in the stacking direction of the flanges facing each other across the central portions of the heat transfer plates have the same height in the stacking direction of the flanges.

9. 8. The method for manufacturing a plate heat exchanger according to claim 7, wherein an end portion of the flange of each of the bent portions in the stacking direction abuts against the flange of an adjacent heat transfer plate in the stacking direction.

Images