JP5012678B2 - Heat exchanger manufacturing method and heat exchanger - Google Patents

Description

  The present invention relates to a heat exchanger manufacturing method in which a water passage is formed inside, and a heat exchanger formed by the manufacturing method.

  As a prior art, there is a heat exchanger disclosed in Patent Document 1 below. In this heat exchanger, the peripheral portions of the two plate members are brazed and joined to form a thin rectangular box, and the corrugated plate having an opening formed by corrugation is formed on the upper and lower folded surfaces (ridge line portions of the corrugated plate). ) And the edge in the ridge line direction are brazed to the plate member and housed in the box, and a water passage is formed between the two plate members and the corrugated plate that folds alternately and meanders.

And when manufacturing this heat exchanger, a corrugated plate is accommodated, the flange part formed in the periphery of two plate members is contact | abutted, a box body is temporarily assembled, and a brazing material is installed in each joining surface. Assemble with a jig. And an assembly is thrown into a heating furnace and heated, and each joining surface is brazed and joined.
JP 2003-314975 A

  When manufacturing the above-described heat exchanger of the prior art, in consideration of improvement of workability and the like, regular brazing material, so-called brazing filler material, is often used instead of paste-like irregular brazing material. When using a regular brazing material, for example, a foil-shaped brazing material is used between the two plate members and the corrugated plate member, and each upper and lower folded surface (each ridge line portion) of the corrugated plate is joined to the plate member. For this purpose, the foil brazing material is arranged so as to extend in a direction perpendicular to the ridgeline of the corrugated plate. And in order to join the edge part of the ridgeline direction of a corrugated board to a plate member reliably, it arrange | positions foil brazing material to the said edge part position of a corrugated board, ie, the position along the wall surface of the peripheral part side of a box. It is common.

  As described above, when the brazing material is disposed between the plate member and the corrugated plate member and heated and brazed, the corrugated plate end can be reliably joined to the plate member, but the corrugated plate member There may be a problem that pitting corrosion occurs on the plate member from the inner surface side which is a water passage at the end in the ridge line direction between adjacent ridge lines.

  The present inventor conducted intensive investigation and examination on the cause of the occurrence of this problem, and found that pitting corrosion occurs due to the mechanism described below.

  In the plate member on the end portion side in the ridge line direction between adjacent ridge lines of the corrugated plate member, the brazing material disposed between the peripheral portions of the plate member and the brazing material disposed between the plate member and the corrugated plate member May cause a coating defect that cannot cover the portion of the plate member that is not in contact with the corrugated plate member, or a brazing material disposed between the plate member and the corrugated plate member at the joint between the plate member and the corrugated plate member. When forming the fillet, there is a case where a coating defect occurs due to sinking. When the state of relatively high corrosive water flowing in the water passage of the heat exchanger continues, galvanic corrosion occurs due to the potential difference between the plate member and the brazing material at the brazing material coating defect portion of the plate member, and the plate member Pitting corrosion occurs.

  From the above knowledge, the present inventor has found that if the current density flowing due to the potential difference is reduced even if a potential difference occurs between the plate member and the brazing material, the plate member can be prevented without preventing the occurrence of relatively difficult coating defects. It has been found that pitting corrosion can be suppressed.

  This invention is made in view of the said point, and is formed with the manufacturing method of a heat exchanger which can suppress that pitting corrosion generate | occur | produces in the plate member which forms a water path, and its manufacturing method. An object is to provide a heat exchanger.

In order to achieve the above object, in the invention described in claim 1,
A corrugated plate member formed into a corrugated shape inside a box-shaped body (27) formed by joining the peripheral portions (251, 261) of the first plate member (25) and the second plate member (26). 24), the ridge line portion (241) of the corrugated plate member (24) is joined to the first and second plate members (25, 26), and the ridge line direction (RR) of the corrugated plate member (24). Are joined to the side wall surface (273) on the peripheral edge (251, 261) side of the box-shaped body (27), and the first and second plate members (25, 26) and the corrugated plate member (24). A method of manufacturing a heat exchanger that forms a water passage (22) there between,
The first plate member (25) and the second plate member are arranged so that the peripheral edge portions (251, 261) are in contact with each other, and the first plate member (25) and the second plate member (26). The corrugated plate member (24) is disposed inside the peripheral portion (251, 261) between the first plate member (25) and the second plate member (26). (251, 261) The first brazing material (28) is arranged at the contact portion between the corrugated plates between the first and second plate members (25, 26) and the corrugated plate member (24). A fixed second brazing material (29) extending in a direction (SS) intersecting the ridgeline of the member (24) is disposed, and has first and second brazing materials (28, 29). 2 plate members (25, 26) and corrugated plate members (2 ) And the assembled unit forming step of forming the assembled unit the (14A) assembled to each other,
After the assembly forming process, the assembly (14A) is heated to melt the first and second brazing materials (28, 29), and the first plate member (25) and the second plate member ( 26) and the joining step of brazing and joining the peripheral portions (251, 261) to the first and second plate members (25, 26) and the corrugated plate member (24) to each other. With
In the assembly process, the second brazing material (29) is disposed away from the side wall surface (273) on the peripheral edge (251, 261) side of the box-shaped body (27). An exposed region in which the inner surfaces (252, 262) of the first and second plate members (25, 26) are exposed at the ends in the ridge line direction (RR) between adjacent ridge line portions (241) of the corrugated plate member (24). (30) is formed.

  According to this, it is possible to form a relatively large exposed region (30) where the brazing material is not covered with the first and second plate members (25, 26). Therefore, even if water flows through the water passage (22) and a potential difference occurs between the first and second plate members (25, 26) and the brazing material (28A, 29A), the current density flowing due to the potential difference is reduced. It can be made relatively small. In this way, pitting corrosion can be suppressed from occurring in the first and second plate members (25, 26).

  The invention according to claim 2 is characterized in that, in the joining step, an exposed region (30) in which the diameter of the inscribed circle is 1.2 mm or more is formed.

  According to this, even if relatively highly corrosive water circulates in the water passage (22), it is possible to reliably suppress the occurrence of pitting corrosion on the first and second plate members (25, 26). it can.

  Moreover, in invention of Claim 3, in an assembly | attachment body formation process, a 2nd brazing material (29) is taken from the side wall surface (273) by the side of the said peripheral part (251,261) of a box-shaped body (27). It is characterized by being arranged 5 mm or more apart.

  According to this, the exposed region (30) in which the diameter of the inscribed circle is 1.2 mm or more can be easily and reliably formed in the joining step.

In the invention according to claim 4,
An exposure in which the inner surfaces (252, 262) of the first and second plate members (25, 26) are exposed on the end side in the ridge line direction (RR) between the adjacent ridge line portions (241) of the corrugated plate member (24). When the region (30) is the first exposed region (30),
In the assembly forming step, the second brazing material (29) is divided into a plurality of parts, each extending in a direction (SS) intersecting the ridge line of the corrugated plate member (24), and arranged in parallel so as to be separated from each other. In the joining step, the inner surfaces (252, 262) of the first and second plate members (25, 26) are exposed between the adjacent ridge line portions (24) of the corrugated plate member (24). A second exposed region (31) different from the one exposed region (30) is formed.

  According to this, the first and second plate members (25, 26) are also used in portions other than the end portion side in the ridge line direction (RR) between the adjacent ridge line portions (241) of the corrugated plate member (24). A relatively large second exposed region (31) that is not covered by the material can be formed. Therefore, it is possible to suppress the occurrence of pitting corrosion in the first and second plate members (25, 26) in the portion other than the end portion side in the ridge line direction (RR) of the corrugated plate member (24). .

  Further, the invention according to claim 5 is characterized in that, in the joining step, the second exposed region (31) in which the diameter of the inscribed circle is 1.2 mm or more is formed.

  According to this, even if relatively corrosive water flows through the water passage (22), pitting corrosion occurs in the first and second plate members (25, 26) in the second exposed region (31). This can be reliably suppressed.

  Further, the invention according to claim 6 is characterized in that, in the assembly forming step, the divided second brazing materials (29) are spaced apart from each other by 5 mm or more.

  According to this, the 2nd exposure area | region (31) from which the diameter of an inscribed circle becomes 1.2 mm or more can be formed easily and reliably at a joining process.

  In the invention described in claim 7, the first and second plate members (25, 26) are made of copper, and the first and second brazing materials (28, 29) are made of a copper-phosphorus alloy. It is a feature.

  According to this, the first and second plate members (25, 26) are base metals and low potential members, and the first and second brazing members (28, 29) are noble metals and high potential members. However, pitting corrosion can be suppressed from occurring in the first and second plate members (25, 26).

In the invention according to claim 8,
A corrugated plate formed into a corrugated shape inside a box-shaped body (27) formed by brazing and joining the peripheral edge portions (251, 261) of the first plate member (25) and the second plate member (26). The corrugated plate member (24) has a ridge line portion (241) brazed to the first and second plate members (25, 26), and the ridge line of the corrugated plate member (24). The end in the direction (RR) is brazed to the side wall surface (273) on the peripheral edge (251, 261) side of the box-shaped body (27), and the first and second plate members (25, 26) and A heat exchanger in which a water passage (22) is formed between the corrugated plate member (24),
An exposed region in which the inner surfaces (252, 262) of the first and second plate members (25, 26) are exposed at the ends in the ridge line direction (RR) between adjacent ridge line portions (241) of the corrugated plate member (24). (30) is a heat exchanger formed.

In addition to this , the heat exchanger is characterized in that the diameter of the inscribed circle of the exposed region (30) is 1.2 mm or more.

  This heat exchanger can be formed by the manufacturing method of the invention described in claim 2.

In the invention according to claim 9 ,
An exposed region in which the inner surfaces (251, 261) of the first and second plate members (25, 26) are exposed at the end portions in the ridge line direction (RR) between the adjacent ridge line portions (241) of the corrugated plate member (24). When (30) is the first exposure region (30),
Different from the first exposed region (30) where the inner surfaces (251, 261) of the first and second plate members (25, 26) are exposed between the adjacent ridge line portions (241) of the corrugated plate member (24). It is a heat exchanger in which the second exposed region (31) is formed.

In addition , the heat exchanger is characterized in that the diameter of the inscribed circle of the second exposed region (31) is 1.2 mm or more.

  This heat exchanger can be formed by the manufacturing method of the invention described in claim 5.

In the invention according to claim 10 , the first and second plate members (25, 26) are made of copper, and the first and second brazing materials (28, 29) are made of copper-phosphorus alloy. It is characterized by being a vessel.

  This heat exchanger can be formed by the manufacturing method according to the seventh aspect of the present invention.

  In addition, the code | symbol in the parenthesis attached | subjected to each said means is an example which shows a corresponding relationship with the specific means as described in embodiment mentioned later.

  Embodiments to which the present invention is applied will be described below with reference to the drawings.

  FIG. 1 is a schematic diagram showing an overall configuration of a heat pump type hot water supply apparatus 20 using a heat exchanger to which the present invention is applied as a hot water supply heat exchanger 14.

  The heat pump hot water supply apparatus 20 includes a hot water storage tank 1 for storing hot water for hot water supply, a heat pump unit 2 that is a hot water supply means for boiling water taken from the hot water storage tank 1, and a circulation circuit 3 that connects the hot water storage tank 1 and the heat pump unit 2. The controller 4 is configured to control the heat pump unit 2.

  First, the hot water storage tank 1 will be described. The hot water storage tank 1 is made of a metal having excellent corrosion resistance, for example, stainless steel, is formed in a vertically long shape, and a heat insulating material (not shown) is disposed on the outer peripheral portion. As a result, hot water for hot water supply can be kept warm in the hot water storage tank 1 for a long time. An introduction port 5 is provided on the bottom surface of the hot water storage tank 1, and an introduction pipe 6 that is a water supply path for introducing tap water into the hot water storage tank 1 is connected to the introduction port 5. An upstream of the introduction pipe 6 is connected to tap water through a pressure reducing check valve (not shown) so as to introduce tap water having a predetermined pressure.

  An outlet 7 is provided at the uppermost part of the hot water storage tank 1, and a hot water supply pipe 8 for connecting hot water in the hot water storage tank 1 is connected to the outlet 7. On the downstream side of the hot water supply pipe 8, for example, a currant, a shower and a bath are provided. Hot water mixing means (not shown) for mixing tap water into the hot water supply pipe 8 is connected to the hot water supply pipe 8 along the route. Thus, hot water in the hot water storage tank 1 and tap water are mixed to obtain hot water at a predetermined temperature. A suction port 1 a for sucking water in the hot water storage tank 1 into the circulation circuit 3 is provided at the lower part of the hot water storage tank 1, and hot water is discharged from the circulation circuit 3 into the hot water storage tank 1 at the upper part of the hot water storage tank 1. A discharge port 1b is provided.

  Next, the circulation circuit 3 will be described. The circulation circuit 3 has an upstream side connected to the suction port 1 a of the hot water storage tank 1 and a downstream side connected to the discharge port 1 b of the hot water storage tank 1. The circulation circuit 3 causes water to flow through the water passage 22 of the hot water supply heat exchanger 14 that constitutes the heat pump unit 2. Therefore, a part of the circulation circuit 3 is disposed in the hot water supply heat exchanger 14 constituting the heat pump unit 2. The circulation circuit 3 heats the water in the hot water storage tank 1 sucked from the suction port 1a by exchanging heat with the high-temperature refrigerant passing through the hot water supply heat exchanger 14 by the hot water supply heat exchanger 14, and the discharge port Return the hot water storage tank 1 from 1b. Thereby, the water in the hot water storage tank 1 is boiled.

  A water feed pump 9 is provided on the downstream side of the suction port 1a to circulate the water in the hot water storage tank 1 in the circulation circuit 3 when boiling. Further, on the downstream side of the water pump 9 and on the upstream side of the hot water supply heat exchanger 14, a flow rate adjusting valve 10 that is a flow rate adjusting means for adjusting the flow rate circulating in the circulation circuit 3 is provided.

  A water temperature sensor 11 that detects the boiling temperature of the water that has flowed out of the hot water supply heat exchanger 14 is provided downstream of the hot water supply heat exchanger 14 and upstream of the discharge port 1b. Further, on the downstream side of the water supply pump 9 and on the upstream side of the flow rate adjustment valve 10, a feed water temperature sensor 12 that detects the temperature of the feed water flowing into the hot water supply heat exchanger 14 is provided. The water temperature sensor 11 and the feed water temperature sensor 12 give the detected temperature information to the control device 4.

  Next, the heat pump unit 2 will be described. The heat pump unit 2 is realized by a supercritical heat pump in the present embodiment. The supercritical heat pump here is a heat pump cycle in which the refrigerant pressure on the high pressure side is equal to or higher than the critical pressure of the refrigerant, and carbon dioxide (CO2) having a low critical temperature is used as the refrigerant.

  The heat pump unit 2 includes a compressor 13, a hot water supply heat exchanger 14, an expansion valve 15, and an evaporating heat exchanger 16, which are sequentially connected in a ring shape by a refrigerant pipe 17. The compressor 13 is driven by a built-in electric motor (not shown), compresses the refrigerant from the evaporating heat exchanger 16 to a critical pressure or higher under general use conditions, and discharges it to the hot water supply heat exchanger 14. .

  The hot water supply heat exchanger 14 exchanges heat between the high-pressure gas refrigerant discharged from the compressor 13 and the water taken from the hot water storage tank 1. This heats the water. Since the refrigerant flowing through the hot water supply heat exchanger 14 is pressurized to a critical pressure or higher by the compressor 13, it does not condense even if the temperature decreases by releasing heat to the water flowing through the hot water supply heat exchanger 14. .

  The expansion valve 15 serving as a decompression unit decompresses the refrigerant flowing out of the hot water supply heat exchanger 14 according to the valve opening degree, and supplies the decompressed refrigerant to the evaporation heat exchanger 16. The opening degree of the expansion valve 15 is electrically controlled by the control device 4.

  The evaporating heat exchanger 16 evaporates the refrigerant decompressed by the expansion valve 15 by heat exchange with the air blown by a blower (not shown). The evaporating heat exchanger 16 gives the evaporated gas phase refrigerant to the compressor 13.

  The heat pump unit 2 can supply a high-temperature refrigerant to the hot water supply heat exchanger 14 by circulating the refrigerant with such a configuration. Since the heat pump unit 2 is a supercritical heat pump, it can boil hot water at a higher temperature (for example, about 85 ° C. or more and about 90 ° C. or less) than a general heat pump cycle.

  Next, the control device 4 will be described. The control device 4 controls the heat pump unit 2 to perform a heating operation of the heat pump unit 2 and store hot water for hot water supply in the hot water storage tank 1. The control device 4 controls the compressor 13, the expansion valve 15, the water supply pump 9, and the flow rate adjustment valve 10 based on an operation signal from an operation panel (not shown) and temperature information from the water temperature sensor 11 and the water supply temperature sensor 12. To do. The control device 4 controls the flow rate adjustment valve 10 based on the boiling temperature information detected by the water temperature sensor 11. In the present embodiment, the flow rate is controlled at a constant boiling temperature. The flow rate may be controlled by changing the water supply capacity of the water supply pump, not by the flow rate adjustment valve. In the boiling operation, the hot water storage amount is detected based on the temperature information of a plurality of water level thermistors (not shown) provided on the outer wall surface of the hot water storage tank 1, and the boiling operation is performed when the temperature becomes equal to or less than a predetermined hot water storage amount. It is configured.

  Next, the hot water supply heat exchanger 14 will be described. FIG. 2 is a front view showing the heat exchanger 14 for hot water supply, and FIG. 3 is a perspective view for explaining the laminated structure of the members constituting the water passage of the heat exchanger 14 for hot water supply.

  As shown in FIG. 3, the heat exchanger 14 for hot water supply includes core plates 25 and 26 (corresponding to first and second plate members) which are two upper and lower plate members obtained by drawing a copper plate into a shallow container shape. And a corrugated plate 24 (corresponding to a corrugated plate member) formed by corrugating a copper plate. The core plates 25, 26 are formed by brazing and joining the peripheral portions 251, 261 to form a thin rectangular box-shaped body 27, and the corrugated plate 24 is accommodated in the box-shaped body 27. Yes.

  The corrugated plate 24 is formed in a plane shape in which the ridge line portion 241 is a flat top and bottom folded surface (mountain surface, trough surface) and the cross section is a continuous rectangular wave, and the outer shape (vertical × horizontal × height) is box-shaped. Fits the internal dimensions of the body 27. On the wall surface of the corrugated plate 24 extending in the vertical direction in the figure, a notch opening is formed at the end in the horizontal direction (ridgeline direction RR) in the figure, and the ridgeline part 241 of the corrugated plate 24 is connected to the bottom surface of the core plates 25 and 26. At the same time, the end portion in the ridge line direction RR of the corrugated plate 24 is brazed to the side wall surface 273 of the box-like body 27 on the peripheral edge portions 251 and 261 side.

  With such a configuration, the box-shaped body 27 composed of the core plates 25 and 26 is partitioned by the corrugated plate 24 and the meandering water passage 22 having a relatively long path that reverses the flow direction at each notch opening. (See FIG. 4) is formed. The corrugated plate 24 is provided for the purpose of increasing the heat transfer area.

  As shown in FIG. 2, the hot water supply heat exchanger 14 includes a plurality of tubes 23 wound spirally around the outer periphery of the box-shaped body 27 and joined to the outer peripheral surface. Inside the tube 23 is a refrigerant passage 21 through which the refrigerant flows, and the hot water supply heat exchanger 14 is configured such that the flow direction of the refrigerant flowing through the refrigerant passage 21 and the flow direction of the water flowing through the water passage 22 face each other. Has been. The hot water supply heat exchanger 14 exchanges heat between the high-temperature refrigerant (hot gas) discharged from the compressor 13 and the water supplied from the hot water storage tank 1 by the water pump 9 as described above.

  Next, a method for manufacturing the hot water supply heat exchanger 14 having the above-described configuration will be described. FIG. 4 is a schematic cross-sectional view of the hot water supply heat exchanger 14, and the upper and lower ends of the tube 23 and the box-shaped body 27 are not shown. 5 is a cross-sectional view taken along line AA in FIG. 4, and FIG. 6 is a cross-sectional view taken along line BB in FIG. 4-6 has shown the state of the assembly | attachment body formation process said by this invention. FIG. 7 is a cross-sectional view of the portion shown in FIG. 6 and shows the state of the joining process referred to in the present invention.

  As shown in FIGS. 4 to 6, in the assembly forming process, the peripheral portions 251, 261 of the core plates 25, 26 are arranged so as to contact each other, and the peripheral portion between the core plate 25 and the core plate 26. The corrugated plate 24 is disposed inside the 251 and 261. At that time, the rod brazing material 28 (the first brazing material is used as the first brazing material) at the contact portion (between the peripheral portion 251 and the peripheral portion 261) between the peripheral portions 251 and 261 of the core plate 25 and the core plate 26. The foil brazing material 29 (corresponding to the second brazing material) is disposed between the core plate 25 and the corrugated plate 24, and between the corrugated plate 24 and the core plate 26, respectively.

  The rod brazing material 28 and the foil brazing material 29 are both regular shaped brazing materials made of a copper-phosphorus alloy (a brazing material that is not indeterminate such as a paste).

  Although not shown in FIG. 3, a side plate 33 made of a copper material extending in the vertical direction in the figure at the left and right ends shown in FIG. 4 is provided inside the box-like body 27 consisting of the core plates 25 and 26. It is arranged. The side plate 33 has a flat shape on the inner peripheral surface side and a shape corresponding to the shape of the joint between the peripheral edge portions 251 and 261 of the core plates 25 and 26 on the outer peripheral surface side (that is, the shape of the side wall surface 273 of the box-shaped body 27). The end portion of the corrugated plate 24 in the ridge line direction RR and the side wall surface 273 on the peripheral edge portions 251 and 261 side of the box-like body 27 are securely joined, and water leaks in the turn portion where the water turns. It is for preventing.

  It can also be said that the core plates 25 and 26 and the side plate 33 constitute the box-like body 27, and the inner side surface of the side plate 33 is a substantial box for joining the end portions in the ridge line direction of the corrugated plate 24. It can also be said that this is the side wall surface of the rod-shaped body.

  The brazing filler metal 28 is disposed to join the peripheral portions 251 and 261 of the core plates 25 and 26 over the entire circumference and to join the core plates 25 and 26 and the side plate 33 together.

  On the other hand, the brazing filler metal 29 is disposed to join the inner surface of the box-like body 27 and the corrugated plate 24, extends in the direction SS perpendicular to the ridgeline of the corrugated plate 24, and is almost the entire length of the corrugated plate 24. It arranges so that it may span. The brazing filler metal 29 is disposed at a distance of 5 mm or more from the side wall surface 273 on the peripheral edge portions 251 and 261 side of the box-shaped body 27. Further, in this example, the foil brazing material 29 is divided into two parts, each extending not only in the direction SS intersecting the ridge line of the corrugated plate 24 but also arranged 5 mm or more apart from each other. That is, the dimension C shown in FIGS. 4 and 6 is 5 mm or more.

  Thus, in the assembly forming process, the core plates 25 and 26, the corrugated plate 24, the side plate 33, the rod brazing material 28 and the foil brazing material 29 are assembled to each other, and the assembled body 14A (mutually fixed to each other). Temporary fixing body) is formed. For example, the core plate 26, the foil brazing material 29, the corrugated plate 24, the side plate 33, the rod brazing material 28, the foil brazing material 29, and the core plate 25 are assembled in this order to form an assembly 14A. be able to.

  When the assembly forming process is completed, a joining process is performed. In the joining process, the assembly 14A formed in the assembly formation process is put into a heating furnace and heated to a predetermined temperature, and the rod brazing material 28 and the foil brazing material 29 are melted. Thereafter, the assembly 14A is taken out of the heating furnace and cooled, and the heat exchanger 14 for hot water supply in which each member is brazed and joined with the brazing filler metals 28A and 29A in which the molten brazing filler metal 28 and the foil brazing filler metal 29 are re-solidified. Get.

  As shown in FIG. 6, in the assembly forming process, the foil brazing material 29 is arranged at a distance of 5 mm or more from the side wall surface 273 on the peripheral edge portions 251 and 261 side of the box-shaped body 27. As shown, when the joining process is performed, the brazing material flows along the ridge line portion 241 of the corrugated plate 24 to the end portion in the ridge line direction RR, and the ridge line portion 241 of the corrugated plate 24 passes through the inner surfaces 252 and 262 of the core plates 25 and 26. And the edge portion RR end of the corrugated plate 24 is joined to the side plate 33. On the other hand, at the end portion in the ridge line direction RR between the adjacent ridge line portions 241 of the corrugated plate 24 (the lower right end portion in the drawing in FIG. 7), although there is a slight amount of brazing material flowing toward the end portion, the core plate An exposed region 30 (corresponding to the first exposed region) is formed in which part of the inner surfaces 252 and 262 of 25 and 26 is exposed (the surface of the copper material is exposed).

  Although not shown in FIGS. 6 and 7, the two ridge brazing materials 29 are arranged 5 mm or more apart from each other as shown in FIG. Also in the substantially central portion between the portions 24, the inner surfaces 252 and 262 of the core plates 25 and 26 are exposed (the copper material surface is exposed), and an exposed region 31 (corresponding to the second exposed region) different from the exposed region 30 It is formed.

  In each of the exposed regions 30 and 31, the distance between the brazing materials facing each other across the regions is 1.2 mm or more. That is, the exposed regions 30 and 31 are formed so that the diameter of the inscribed circle is 1.2 mm or more.

  According to the above-described configuration and manufacturing method, in the assembly forming process, the foil brazing material 29 is separated by 5 mm or more from the side wall surface 273 on the peripheral edge portions 251 and 261 side of the box-shaped body 27 including the core plates 25 and 26. By arranging, in the joining process, the inner surface 252 and 262 of the core plates 25 and 26 are exposed at the end in the ridge line direction RR between the adjacent ridge lines 241 of the corrugated plate 24, and the diameter of the inscribed circle is 1.2 mm. The exposed region 30 described above is formed.

  Further, the brazing filler metal 29 is divided into two parts, each extending in a direction SS perpendicular to the ridge line of the corrugated plate 24 and arranged in parallel so as to be separated from each other by 5 mm or more. An exposed region 31 having an inscribed circle diameter of 1.2 mm or more is formed in which the inner surfaces 252 and 262 of the core plates 25 and 26 are exposed at the central portion in the ridge line direction RR between the 24 adjacent ridge line portions 24.

  Accordingly, relatively large exposed regions 30 and 31 that are not covered with the brazing materials 28A and 29A can be formed on the core plates 25 and 26. Therefore, even if water flows through the water passage 22 of the heat exchanger 14 for hot water supply and a potential difference occurs between the core plates 25 and 26 and the brazing materials 28A and 29A, the exposed regions 30 and 31 are relatively wide. The current density flowing due to the potential difference can be made relatively small. In this way, pitting corrosion can be reliably suppressed from occurring in the core plates 25 and 26.

  As shown in FIG. 11, the present inventor shows the heat exchanger 914 for hot water supply of the comparative example, the position of the corrugated plate 24 in the ridge line direction RR, that is, the position along the side wall surface 273 on the peripheral side of the box-shaped body 27. It has been confirmed that when the brazing filler metal 29 is disposed at a position (specifically, along the side plate 33), pitting corrosion may occur in the core plates 25 and 26.

  As shown in FIG. 12, the foil brazing material 29 is disposed up to the end of the corrugated plate 24 in the ridge line direction RR in the assembly forming process, and the joining process is performed. As shown in FIG. 13, the brazing material flows and brazing joining is performed between the members.

  At this time, between the adjacent ridge line portions of the corrugated plate 24, as shown in FIG. 14, a brazing material that joins the core plate 26 and the side plate 33 at the corner portion between the bottom surface portion and the side wall surface portion of the box-shaped body 27. 28A and the brazing material 29A that joins the core plate 26 and the corrugated plate 24 cause a coating defect that cannot cover the surface of the base material of the core plate 26. For example, residual chlorine and free carbonic acid are generated in the water passage of the heat exchanger. Pitting corrosion occurs when highly concentrated and relatively highly corrosive water flows.

  Further, as shown in FIG. 15, between the adjacent ridge portions of the corrugated plate 24, when the corrugated plate 24 and the core plates 25 and 26 are brazed and joined in the joining step, a brazing filler fillet is formed at the joined portion. In addition, a part of the brazing material on the surface of the core plates 25 and 26 is pulled to the fillet to cause sinking and a coating defect occurs. For example, residual chlorine and free carbon dioxide are high in the water passage of the heat exchanger. Pitting corrosion occurs when highly corrosive water flows.

  The main cause of such corrosion (pitting corrosion) is galvanic corrosion caused by the potential difference between the high potential member and the low potential member. The brazing material is a precious metal and becomes a high potential member, the base material is a base metal and a low potential member, and the base material of highly corrosive water and core plate that touches the brazing material in a small area. It has been confirmed that corrosion (pitting corrosion) progresses at an accelerated rate due to contact.

  The present inventor investigated the distance (that is, the corrosion diameter) in which the potential difference between the core plate and the brazing material affects the corrosion in the combination of the core plate and the brazing material, and circulated highly corrosive water. Then, it was confirmed that the corrosion diameter at which pitting corrosion progresses on the core plate is 1.2 mm. That is, corrosion (pitting corrosion) is determined by the area ratio of a high potential member (hereinafter referred to as a cathode) that forms a brazing material within a range of a corrosion diameter of 1.2 mm and a low potential member (hereinafter referred to as an anode) that forms a base material of the core plate.

  Therefore, as shown in FIG. 8, the present inventor changed the area ratio of the cathode and the anode at a corrosion diameter of 1.2 mm using a joint portion between the corrugated plate 24 and the core plates 25 and 26, and the core plate base material. As a result of measuring the magnitude of the corrosion current density due to the exposed width of the electrode, if the ratio of the cathode width to the anode width is 0.3, the current density is 1/9 compared to the ratio of 3, and the ratio is 47. It was confirmed to be 1/135 with respect to the case. That is, it was confirmed that the smaller the exposed width of the core plate base material within the corrosion diameter, that is, the narrower the anode, the greater the corrosion current density and the faster the corrosion (pitting corrosion).

  Therefore, it was found that even if surrounded by the brazing material, the corrosion current density is small and the corrosion (pitting corrosion) can be generally prevented if the exposed width of the core plate base material surface having a corrosion diameter of 1.2 mm or more.

  From the above knowledge, the exposed regions 30 and 31 of the core plates 25 and 26 preferably have an inscribed circle diameter of 1.2 mm. In order to form such exposed regions 30 and 31, In consideration of the flowability of the molten brazing material, in the assembly forming process, the foil brazing material 29 is separated by 5 mm or more from the side wall surface 273 of the peripheral portion 251, 261 side of the box-shaped body 27 composed of the core plates 25, 26. The present inventors have found that it is preferable to arrange the two brazing filler metals 29 side by side so as to be separated from each other by 5 mm or more.

(Other embodiments)
In the one embodiment, the foil brazing material 29 is arranged so as to extend in the direction SS orthogonal to the ridge line of the corrugated plate 24, but is not limited to the orthogonal arrangement, and extends in a direction intersecting with the ridge line. What is necessary is just to arrange | position so that it may hang.

  Moreover, in the said one Embodiment, although the foil brazing material 29 was divided | segmented and arrange | positioned into two, one may be sufficient and it may divide | segment and arrange | position into three or more. For example, as shown in FIG. 9, in order to ensure the amount of brazing material necessary for joining, a foil brazing material 129 having a thickness twice that of the brazing brazing material 29 of the above embodiment is adopted. Only one may be arranged at the center to reduce the arrangement area by half. Further, as shown in FIG. 10, a foil brazing material 229 obtained by dividing the foil brazing material 129 into two parts is adopted, and these are arranged in parallel while being separated from each other, and the installation area and the amount of the brazing material are the same as those in FIG. It may be.

  In the above embodiment, in the assembly forming process, the foil brazing material 29 is arranged at a distance of 5 mm or more from the side wall surface 273 on the peripheral edge 251, 261 side of the box-shaped body 27 composed of the core plates 25, 26. The two brazing filler metals 29 were arranged side by side so as to be separated from each other by 5 mm or more. However, as long as the diameter of the inscribed circle of the exposed regions 30 and 31 can be secured to 1.2 mm or more, it is limited to this. It is not a thing.

  In the above-described embodiment, the second brazing material is the foil brazing material 29, but the present invention is not limited to this as long as it is a regular brazing material. Further, the first brazing material is the rod brazing material 28, but is not limited to this, and may be another regular brazing material or an irregular brazing material.

  In the above-described embodiment, the box-shaped body 27 is formed by combining the two core plates 25 and 26 formed by drawing. However, the form of the plate member is not limited to this, and for example, a plate formed by drawing. A box-shaped body may be formed by combining a member and a flat plate member.

  Moreover, although the case where this invention of the hot water supply heat exchanger 14 was applied was demonstrated in the said one Embodiment, if it is a heat exchanger which forms a water path, this invention is effective.

It is a schematic diagram which shows the whole structure of the heat pump type hot water supply apparatus 20 which used the heat exchanger in one Embodiment to which this invention was applied as the heat exchanger 14 for hot water supply. It is a front view which shows the heat exchanger 14 for hot water supply. It is a perspective view explaining the laminated structure of the member which comprises the water path of the heat exchanger 14 for hot water supply. It is a schematic sectional drawing of the heat exchanger 14 for hot water supply. It is the sectional view on the AA line of FIG. It is the BB sectional view taken on the line of FIG. It is sectional drawing which shows the state of the joining process of the site | part shown in FIG. It is a perspective view which shows the structure of the joining site | part at the time of measuring a corrosion current density. It is a schematic sectional drawing of the heat exchanger for hot water supply in other embodiment. It is a schematic sectional drawing of the heat exchanger for hot water supply in other embodiment. It is a schematic sectional drawing of the heat exchanger 914 for hot water supply of a comparative example. It is the EE sectional view taken on the line of FIG. It is sectional drawing which shows the state of the joining process of the site | part shown in FIG. It is sectional drawing which shows the generation | occurrence | production form of pitting corrosion in a comparative example. It is sectional drawing which shows the generation | occurrence | production form of pitting corrosion in a comparative example.

Explanation of symbols

14 Heat exchanger for hot water supply 14A Assembly 22 Water passage 24 Corrugated plate (corrugated plate member)
25 Core plate (first plate member)
26 Core plate (second plate member)
27 Box-shaped body 28 Bar brazing material (first brazing material)
29 Foil brazing material (second brazing material)
30 exposed area (first exposed area)
31 Exposed area (second exposed area)
241 Ridge part 251, 261 Peripheral part (peripheral part of core plate)
252 and 262 inner surface (inner surface of core plate)
273 Side wall surface (side wall surface of box-shaped body)
RR Ridge direction SS Direction perpendicular to the ridge line (direction intersecting the ridge line)

Claims (10)

A corrugated plate member formed into a corrugated shape inside a box-shaped body (27) formed by joining the peripheral portions (251, 261) of the first plate member (25) and the second plate member (26). 24), the ridge line portion (241) of the corrugated plate member (24) is joined to the first and second plate members (25, 26), and the ridge line direction of the corrugated plate member (24) The end of (RR) is joined to the side wall surface (273) on the peripheral edge (251, 261) side of the box-shaped body (27), and the first and second plate members (25, 26) and A heat exchanger manufacturing method for forming a water passage (22) between the corrugated plate member (24),
The first plate member (25) and the second plate member (26) are arranged so that peripheral portions (251, 261) are in contact with each other, and the first plate member (25) and the first plate member (25) are arranged. The corrugated plate member (24) is disposed inside the peripheral edge portion (251, 261) between the two plate members (26), and further, the first plate member (25) and the second plate The first brazing material (28) is disposed at the contact portion between the peripheral portions (251, 261) with the member (26), and the first and second plate members (25, 26) and the corrugated plate member A second brazing material (29) having a fixed shape extending in a direction (SS) intersecting the ridge line of the corrugated plate member (24) is disposed between the first and second brazing materials. (28, 29) having the first and second And the assembled unit forming step of forming rate members (25, 26) and the corrugated plate members (24) assembled body assembled to each other and (14A),
After the assembly forming step, the assembly (14A) is heated to melt the first and second brazing materials (28, 29), and the first plate member (25) and the first The peripheral portions (251, 261) of the two plate members (26) are brazed to each other, and the first and second plate members (25, 26) and the corrugated plate member (24) are mutually connected. A joining process for brazing,
In the assembly forming step, the second brazing material (29) is disposed away from the side wall surface (273) on the peripheral edge (251, 261) side of the box-shaped body (27). In the joining step, the inner surfaces (252, 26) of the first and second plate members (25, 26) at the end portions in the ridge line direction (RR) between the adjacent ridge line portions (241) of the corrugated plate member (24). A method of manufacturing a heat exchanger, characterized in that an exposed region (30) in which 262) is exposed is formed.   2. The method for manufacturing a heat exchanger according to claim 1, wherein, in the joining step, the exposed region (30) having an inscribed circle diameter of 1.2 mm or more is formed.   In the assembly forming step, the second brazing material (29) is disposed at a distance of 5 mm or more from the side wall surface (273) on the peripheral edge (251, 261) side of the box-shaped body (27). The manufacturing method of the heat exchanger of Claim 2 characterized by these. The inner surfaces (252, 262) of the first and second plate members (25, 26) are exposed on the end side in the ridge line direction (RR) between the adjacent ridge line portions (241) of the corrugated plate member (24). When the exposed area (30) to be used is the first exposed area (30),
In the assembly forming step, the second brazing material (29) is divided into a plurality of parts, each extending in a direction (SS) intersecting a ridge line of the corrugated plate member (24) and spaced apart from each other. By arranging in parallel, in the joining step, the inner surfaces (252, 262) of the first and second plate members (25, 26) between the adjacent ridge line portions (24) of the corrugated plate member (24). The method of manufacturing a heat exchanger according to any one of claims 1 to 3, wherein a second exposed region (31) different from the first exposed region (30) is formed. .   5. The method of manufacturing a heat exchanger according to claim 4, wherein, in the joining step, the second exposed region (31) in which a diameter of an inscribed circle is 1.2 mm or more is formed.   6. The method of manufacturing a heat exchanger according to claim 5, wherein in the assembly forming step, the divided second brazing materials (29) are spaced apart from each other by 5 mm or more.   The first and second plate members (25, 26) are made of copper, and the first and second brazing materials (28, 29) are made of a copper-phosphorus alloy. A method for producing a heat exchanger according to any one of claims 6 to 10. A corrugated plate formed into a corrugated shape inside a box-shaped body (27) formed by brazing and joining the peripheral edge portions (251, 261) of the first plate member (25) and the second plate member (26). A ridge line portion (241) of the corrugated plate member (24) is brazed to the first and second plate members (25, 26) and the corrugated plate member (24). ) In the ridge line direction (RR) is brazed to the side wall surface (273) on the peripheral edge (251, 261) side of the box-shaped body (27), and the first and second plate members (25, 26) and a heat exchanger in which a water passage (22) is formed between the corrugated plate member (24),
Inner surfaces (252, 262) of the first and second plate members (25, 26) are exposed at end portions in the ridge line direction (RR) between adjacent ridge line portions (241) of the corrugated plate member (24). An exposed region (30) is formed ;
In the heat exchanger, the exposed area (30) has an inscribed circle diameter of 1.2 mm or more . Inner surfaces (251, 261) of the first and second plate members (25, 26) are exposed at end portions in the ridge line direction (RR) between adjacent ridge line portions (241) of the corrugated plate member (24). When the exposure area (30) is the first exposure area (30),
The first exposed region (30) in which inner surfaces (251, 261) of the first and second plate members (25, 26) are exposed between adjacent ridge line portions (241) of the corrugated plate member (24). And a second exposed region (31) different from is formed ,
The heat exchanger according to claim 8 , wherein the second exposed region (31) has an inscribed circle diameter of 1.2 mm or more . Said first, second plate member (25, 26) is made of copper, the first, second brazing material (28, 29) is a copper - claim 8 or claim, characterized by comprising the phosphorus alloy The heat exchanger according to 9 .

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