JP2010167445A - Method of manufacturing heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a heat exchanger, the method suppressing deterioration in heat exchanging efficiency and having excellent productivity. <P>SOLUTION: The manufacturing method includes: a process of arranging a first metallic tube and a second metallic tube each having a fluid passage formed inside in a laminated manner in the thickness direction; a process of packing, in the fluid passage 53 of the laminated body, a filling material having a larger electric resistance than that of the first metallic tube 47; a process of arranging the laminated body between roller electrodes 71, 73 and moving the laminated body along the longitudinal direction relative to the roller electrodes 71, 73 while pressurizing the laminated body in the thickness direction with the roller electrodes 71, 73, and resistance welding the laminated body; and a process of removal of the filling material from the fluid passage 53 after the resistance welding. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a heat exchanger.

  Seam welding, which is a type of resistance welding, is excellent in productivity in that it allows continuous joining of parts to be joined, and is used in various applications.

  For example, as disclosed in Patent Documents 1 and 2, seam welding is used when a metal pipe is formed by rolling a steel plate. Specifically, electrodes are arranged in the vicinity of both end faces of a steel plate that is rolled into a tubular shape and is opposed to each other, and a continuous seam is passed by passing an electric current through the electrodes while relatively moving the electrodes along the end faces. Forms and manufactures steel pipes.

  Seam welding is also used when manufacturing fuel tanks for vehicles. Specifically, the flange portions provided around each of the two metal plates each having a recess are overlapped, and the flange portions are welded together by passing current between them with a pair of roller electrodes sandwiched between them. To produce fuel tanks.

JP 62-50088 A JP 54-112370 A

  By the way, in a heat exchanger used for an air conditioner, a heat pump type hot water heater or the like, a metal tube having a refrigerant flow channel through which a refrigerant flows and a metal tube having a fluid flow channel through which a fluid such as water or refrigerant flows. Need to be joined to each other, and if the above resistance welding is applied to join these metal tubes, the following problems arise.

  That is, when joining metal tubes by resistance welding, it is necessary to weld a plurality of stacked metal tubes while pressing them in the stacking direction with a pair of roller electrodes. However, if resistance welding is performed while pressing a hollow metal tube with a pair of roller electrodes, the metal tube is crushed and the hollow portion is almost lost, so that the metal tube can sufficiently function as a refrigerant or fluid flow path. Therefore, the desired heat exchange efficiency cannot be obtained. On the other hand, when the pressurization in the stacking direction to the plurality of metal tubes is insufficient, the metal tubes are not sufficiently joined to each other, so that the efficiency of heat exchange decreases.

  Therefore, the present invention has been made in view of such a point, and an object of the present invention is to provide a method of manufacturing a heat exchanger that can suppress a decrease in efficiency of heat exchange and is excellent in productivity. is there.

  The manufacturing method of the present invention is a method for manufacturing a heat exchanger for exchanging heat between fluids flowing through adjacent metal pipes, and has a flat shape whose width is larger than thickness. The first metal pipe (47) in which the fluid flow path (53) is formed along the longitudinal direction, and a flat shape having a width larger than the thickness, and a plurality of fluid flows along the longitudinal direction. A step of laminating and arranging a second metal tube (45) having a passage (51) formed therein in the thickness direction, with the longitudinal direction and the thickness direction of both being aligned in the same direction, and the first metal tube ( 47) filling the fluid flow path (53) with a filler having a higher electric resistance than the first metal pipe (47), and the first metal pipe (47) and the second metal arranged in a stacked manner. Place the tube (45) between the pair of roller electrodes (71, 73) The first metal tube (47) and the second metal tube (45) are pressed in the longitudinal direction with respect to the pair of roller electrodes (71, 73) while being pressed in the thickness direction by a pair of roller electrodes (71, 73). The first metal tube (47) and the second metal tube (45) are resistance-welded by relatively moving along the line, removing the filler from the fluid flow path (53) after the resistance welding, It has.

  In this configuration, the first metal pipe (47) and the second metal pipe (45) are filled by filling the fluid flow path (53) of the first metal pipe (47) with a filler having a larger electric resistance than the metal pipe. Since resistance welding is performed, the second metal pipe (45) is a multi-hole pipe, so that deformation is suppressed, while the first metal pipe (47) is filled with a filler in the fluid flow path (53). Deformation is suppressed. In this way, the filler serves to suppress deformation of the metal tube during welding, and by suppressing the deformation, the filler is sufficient in the thickness direction with respect to the first metal tube (47) and the second metal tube (45). Welding is possible while applying appropriate pressure. As a result, a sufficient bonding area between the metal tubes can be ensured while sufficiently securing the flow paths inside the metal tubes, so that a reduction in heat exchange efficiency can be suppressed and productivity is also excellent.

  In addition, another manufacturing method of the present invention is a method for manufacturing a heat exchanger that exchanges heat between fluids flowing through adjacent metal pipes, and has a flattened width that is larger than the thickness. The first metal pipe (47) in which the fluid flow path (53) is formed along the longitudinal direction and the flat shape having a width larger than the thickness are formed along the longitudinal direction. A step of laminating and arranging the second metal pipe (45) in which the fluid flow path (51) is formed in the thickness direction so that both the longitudinal direction and the thickness direction thereof are aligned in the same direction; Filling each fluid flow path of the pipe (47) and the second metal pipe (45) with a filler having a larger electric resistance than these metal pipes, and the first metal pipe (47) arranged in a stacked manner ) And the second metal tube (45) are connected to a pair of roller electrodes (71 73) and the first metal tube (47) and the second metal tube (45) are placed in the pair of roller electrodes (71, 73) while being pressed in the thickness direction by the pair of roller electrodes (71, 73). 73) a step of resistance welding the first metal pipe (47) and the second metal pipe (45) by relative movement along the longitudinal direction with respect to the longitudinal direction, and the filler from the fluid flow path after the resistance welding. And a step of removing.

  In this configuration, each of the first metal pipe (47) and the second metal pipe (45) is filled with a filler having a larger electric resistance than the first metal pipe (47) and the second metal pipe (45). Since the second metal pipe (45) is resistance-welded, the filler serves to suppress deformation of the metal pipe during welding, and the first metal pipe (47) and the second metal pipe are suppressed by suppressing the deformation. With respect to (45), welding can be performed while applying sufficient pressure in the thickness direction. As a result, a sufficient bonding area between the metal tubes can be ensured while sufficiently securing the flow paths inside the metal tubes, so that a reduction in heat exchange efficiency can be suppressed and productivity is also excellent.

  When the filler is sand, it has appropriate fluidity, so that it is easy to fill the metal tube with the filler, and it is also easy to extract the filler from the metal tube after welding. Moreover, since sand has a high hardness, it is possible to further suppress deformation of the metal tube during welding. As a result, a sufficient flow path inside the metal tube can be secured, and welding can be performed while applying a greater pressure in the thickness direction to the first metal tube (47) and the second metal tube (45). Since it can do, the junction area of metal tubes can be enlarged further.

  When the filler is a granular heat-resistant resin, it has appropriate fluidity, so it is easy to fill the filler into the metal tube, and the filler can be extracted from the metal tube after welding. Easy.

  When the filler is a liquid, it has fluidity, so it is easy to fill the metal tube with the filler, and it is also easy to extract the filler from the metal tube after welding. Moreover, since the filler is a liquid, an effect of cooling the metal tube can be obtained. Thereby, it can suppress that the temperature of a metal pipe rises too much with the heat | fever generate | occur | produced at the time of welding.

  In the resistance welding step, the first metal tube (47) and the second metal tube (45) are resistance welded in a state where the openings at both ends of the metal tube are closed, so that the filler is a metal tube. It is possible to suppress the outflow from the end portion.

  Further, when the filler is liquid, in the resistance welding step, the longitudinal direction of the first metal pipe (47) and the second metal pipe (45) arranged in layers is inclined from the vertical direction or from the vertical direction. The first metal tube (47) and the second metal tube (45) are disposed in an oblique direction and the first metal tube (47) and the second metal tube (45) are in a state in which the opening of at least the lower end of the metal tube filled with the filler is closed. It is preferable that the first metal pipe (47) and the second metal pipe (45) are resistance-welded by moving relative to the pair of roller electrodes (71, 73) in the longitudinal direction.

  In this configuration, the longitudinal directions of the first metal pipe (47) and the second metal pipe (45) are arranged in the vertical direction or the oblique direction, and at least the opening at the lower end of the metal pipe filled with the filler is provided. Since resistance welding is performed in the closed state, it is possible to suppress the liquid filler from flowing out of the metal tube, and it is possible to reduce the horizontal area required at the manufacturing site.

  Further, in this case, in the resistance welding step, the pair of roller electrodes (71, 73) are moved in the vertical direction or in the oblique direction, so that the first metal pipe (47) and the second metal pipe (45) are moved. Are preferably resistance welded.

  In this configuration, the pair of roller electrodes (71, 73) is moved in the vertical direction or in the oblique direction and resistance welding is performed, so that it is possible to perform stable production without having to move the long metal pipe in the vertical direction or in the oblique direction, and The vertical height required at the manufacturing site can be reduced.

  Further, in the present invention, in the stacking and arranging step, the second metal tube (45), the first metal tube (47), and a flat shape whose width is larger than the thickness are formed along the longitudinal direction. And a third metal pipe (49) having a plurality of fluid flow paths (51) formed therein in this order in the thickness direction, and in the resistance welding step, the first metal pipe (47), Preferably, two metal pipes (45) and a third metal pipe (49) are arranged between the pair of roller electrodes (71, 73) and resistance welding is performed.

  In this configuration, since the second metal tube (45) and the third metal tube (49) are stacked on both sides of the first metal tube (47) in the thickness direction, the efficiency of heat exchange between the refrigerant and the fluid is improved. It can be improved further. The second metal tube (45) and the third metal tube (49) are multi-hole tubes in which a plurality of fluid flow paths (51) are formed along the longitudinal direction. 45) and the drift of the fluid flowing through the third metal pipe (49) can be suppressed, and the efficiency of heat exchange with the fluid flowing through the first metal pipe (47) can be further improved.

  As described above, according to the method for manufacturing a heat exchanger of the present invention, the fluid flow path of the first metal tube is filled with the filler having a larger electric resistance than these metal tubes, and the first metal tube and the first metal tube Since the two metal pipes are resistance welded, the filler plays a role of suppressing the deformation of the first metal pipe at the time of welding, and the thickness direction with respect to the first metal pipe and the second metal pipe is suppressed by the deformation. It is possible to perform welding while applying sufficient pressure. Thereby, it is possible to sufficiently secure the joint area between the metal tubes while sufficiently securing the fluid flow path inside the first metal tube, and thus it is possible to suppress a decrease in the efficiency of heat exchange. In addition, this method is excellent in productivity because metal tubes can be joined continuously using resistance welding.

It is a perspective view which shows an example of the heat exchanger obtained by the manufacturing method concerning one Embodiment of this invention. It is the II-II sectional view taken on the line of FIG. It is a front view which shows the manufacturing method of the heat exchanger concerning one Embodiment of this invention. It is a perspective view which shows the other example of the heat exchanger obtained by the manufacturing method concerning one Embodiment of this invention. It is a front view which shows the manufacturing method of the heat exchanger concerning other embodiment of this invention. It is a block diagram which shows a heat pump type water heater.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

<Heat exchanger>
As shown in FIGS. 1 and 2, a heat exchanger 21 obtained by a manufacturing method according to an embodiment of the present invention to be described later has one end 41 in the longitudinal direction arranged on the inside and the other end 43 in the longitudinal direction on the outside. It has the structure wound by the spiral shape so that it may be arrange | positioned. The heat exchanger 21 has a structure in which a second metal tube 45, a first metal tube 47, and a third metal tube 49 are stacked in this order in the thickness direction. These metal pipes 45, 47, and 49 are integrated by joining opposite outer surfaces by resistance welding described later.

  The second metal tube 45 and the third metal tube 49 have flat shapes each having a width larger than the thickness. These metal tubes 45 and 49 are multi-hole tubes in which a plurality of refrigerant channels 51 extending in the longitudinal direction are formed inside. The plurality of refrigerant flow paths 51 are independent from each other, and are arranged in a line in the width direction. For example, the refrigerant circulating in the refrigerant circuit 13 of the heat pump type hot water heater 11 described later flows in each refrigerant flow path 51. Since the second metal tube 45 and the third metal tube 49 are multi-hole tubes, the drift of the refrigerant flowing through the refrigerant flow channel 51 can be suppressed.

  The first metal tube 47 has a flat shape whose width is larger than thickness. A fluid channel 53 extending in the longitudinal direction is formed inside the metal tube 47. For example, water circulating in the hot water storage circuit 17 of the heat pump type hot water heater 11 described later flows through the fluid flow path 53.

  The first metal tube 47 has an outer surface 61 on one side in the thickness direction and an outer surface 63 on the other side. The second metal tube 45 has a facing surface 65 facing the outer surface 61 on one side of the first metal tube 47, and is laminated on one side in the thickness direction with respect to the first metal tube 47. The third metal tube 49 has a facing surface 67 that faces the outer surface 63 on the other side of the first metal tube 47, and is laminated on the other side in the thickness direction with respect to the first metal tube 47.

  At least a part of the facing surface 65 of the second metal tube 45 is fused with the outer surface 61. At least a part of the facing surface 67 of the third metal tube 49 is fused with the outer surface 63. As the ratio of the facing surfaces 65 and 67 fused to the outer surfaces 61 and 63 increases, the degree of close contact between the facing surfaces 65 and 67 and the outer surfaces 61 and 63 improves, and the heat exchange efficiency of the heat exchanger 21 increases. Can be increased. The fusion welding ratio between the facing surfaces 65 and 67 and the outer surfaces 61 and 63 can be adjusted by changing the welding conditions during resistance welding. Specifically, for example, the facing surfaces 65, 67 and the outer surface are set by setting conditions such as a slow welding speed (feeding speed) during resistance welding, a large current value during welding, and a large pressing force in the thickness direction during welding. The fusion welding ratio of the surfaces 61 and 63 can be increased. Therefore, in terms of the efficiency of heat exchange of the heat exchanger 21, it is preferable that the opposing surfaces 65 and 67 are almost entirely fused with the outer surfaces 61 and 63.

  As materials for the first metal tube 47, the second metal tube 45, and the third metal tube 49, metals having thermal conductivity, corrosion resistance, rigidity, workability, and the like are used. Specifically, aluminum and aluminum alloys are used. Etc. can be exemplified.

<Manufacturing method of heat exchanger>
(First embodiment)
Next, the manufacturing method of the heat exchanger 21 concerning 1st Embodiment of this invention is demonstrated. As shown in FIG. 3, a resistance welding apparatus 100 is used for manufacturing the heat exchanger 21.

  First, the resistance welding apparatus 100 will be described. The resistance welding apparatus 100 includes a pair of roller electrodes 71 and 73, a pressure device 75 that pressurizes the roller electrode 71, a power supply device 79 that supplies power to the pressure device 75 and the roller electrodes 71 and 73, And a control unit (not shown) for controlling the operation of the part.

  The roller electrode 71 and the roller electrode 73 are substantially cylindrical, and have rotating shafts 72 and 74 at the centers, respectively. The rotating shaft 72 and the rotating shaft 74 are disposed substantially parallel to each other. The axial widths of the roller electrodes 71 and 73 are designed to be larger than the widths of the first metal tube 47, the second metal tube 45 and the third metal tube 49 to be welded.

  A motor (not shown) is connected to each of the rotating shafts 72 and 74, and is supported by a support base (not shown) so as to be rotatable around the axis. The motor is connected to a power supply device 79. The roller electrode 71 and the roller electrode 73 rotate in opposite directions. For example, in FIG. 3, the roller electrode 71 rotates counterclockwise, and the roller electrode 73 rotates clockwise. The roller electrode 71 is supported by a support base so as to be movable in a direction approaching the roller electrode 73 and in the opposite direction (vertical direction in FIG. 3), and the roller electrode 73 is fixed to the support base. These roller electrodes 71 and 73 are connected to a power supply device 79, and electric power is supplied by the power supply device 79 during resistance welding. It should be noted that, instead of the structure in which only the roller electrode 71 moves in the vertical direction as in this embodiment, a structure in which both the roller electrodes 71 and 73 move in the vertical direction may be used.

  The pressurizing device 75 includes a cylindrical cylinder 78, a piston 77 disposed inside the cylinder 78, and a pump (not shown) that generates energy such as air pressure and hydraulic pressure. When power is supplied from the power supply device 79, the pressurizing device 75 drives the pump to slide the piston 77 in a predetermined direction in the cylinder 78. Thereby, the roller electrode 71 is pressurized. The pressed roller electrode 71 moves toward the roller electrode 73, and the first metal tube 47, the second metal tube 45, and the third metal tube 49 disposed between the roller electrodes 71 and 73 are added in the thickness direction. Press.

  Next, each manufacturing process will be described. First, in the metal tube forming step, the first metal tube 47, the second metal tube 45, and the third metal tube 49 are produced.

  The first metal tube 47 is obtained by bending an elongated metal flat plate (not shown) so that the end portions in the width direction face each other and a space is formed along the longitudinal direction inside, and the ends are joined together. . An inner space along the longitudinal direction becomes a fluid flow path 53. The first metal tube 47 can also be produced by extruding a metal material using a mold having an extrusion outlet having the cross-sectional shape of the first metal tube 47 as shown in FIG.

  The second metal tube 45 and the third metal tube 49 can be produced by extruding a metal material using a mold having an extrusion outlet having a cross-sectional shape of the metal tubes 45 and 49 as shown in FIG. it can.

  Next, a filler is filled into the fluid flow path 53 of the first metal tube 47. In the present embodiment, a granular material having a larger electric resistance than the first metal tube 47 is used as the filler. Examples of the granular filler include sand and granular heat-resistant resin.

  The heat-resistant resin is not particularly limited as long as it can be used for a long time even at the temperature of the first metal tube 47 rising during resistance welding. For example, a fluororesin such as polytetrafluoroethylene (PTFE), polyethersulfone ( PES), polyetheretherketone (PEEK), polyamideimide (PAI), polyimide (PI) and the like can be exemplified.

  The particle size of the granular filler may be appropriately adjusted according to the thickness and width of the fluid flow path 53 of the first metal tube 47, the material constituting the filler, the required fluidity, and the like. When the fluidity of the granular filler is higher, the granular filler is more easily filled into the fluid flow path 53, and is more easily taken out from the fluid flow path 53 after resistance welding. Further, as the fluidity of the granular filler increases, the granular filler filled in the first metal tube 47 tends to flow out from the opening at the end of the first metal tube 47. Resistance welding is preferably performed with the opening at one or both ends closed. By appropriately adjusting the fluidity of the granular filler, it is possible to easily fill the fluid channel 53, to easily remove the fluid from the fluid channel 53, and to prevent the fluid from flowing out from the end opening.

  The closing member that closes the opening of the end portion of the first metal tube 47 is a plug (not shown) that can be inserted into the fluid flow channel 53 from the opening and fixed in that state, and the illustration is omitted that covers the opening and can be fixed in that state. A lid can be used.

  As a method for filling the fluid flow channel 53 of the first metal tube 47 with the granular filler, for example, in a state where one end of the first metal tube 47 is closed by a closing member, the granular filler is introduced from the other end. The method of pouring the fluid into the fluid flow path 53 is exemplified. In the case of this method, the first metal tube 47 is directed in the vertical direction or in an oblique direction inclined from the vertical direction with the closed end portion disposed below, and the granular filler material is disposed from the other end portion disposed above. Can be poured smoothly into the fluid flow path 53. In addition, you may perform the process of filling this granular filler between the lamination | stacking arrangement | positioning process and resistance welding process which are mentioned later.

  Next, the first metal tube 47, the second metal tube 45, and the third metal tube 49 are stacked. As shown in FIG. 3, the second metal tube 45, the first metal tube 47, and the third metal tube 49 are arranged in the thickness direction in this order, with their longitudinal direction and thickness direction aligned in the same direction. The

  Next, the second metal tube 45, the first metal tube 47, and the third metal tube 49 (hereinafter referred to as a laminated body) arranged in a stacked manner in the laminated arrangement step are supplied between the roller electrodes 71 and 73 and are longitudinally arranged. The roller electrodes 71 and 73 are resistance welded (seam welded). Since the granular filler has an electric resistance larger than that of the first metal tube 47, the current during resistance welding mainly flows through the first metal tube 47.

  Next, the particulate filler is removed from the fluid flow path 53 after this resistance welding. As a method for removing the granular filler, for example, the one end of the laminate is directed in the vertical direction or in an oblique direction inclined from the vertical in a state where one end of the resistance welded laminate is disposed below. A method of discharging the particulate filler in the fluid flow path 53 of the first metal pipe 47 is mentioned.

  In this way, a linear heat exchanger 21 in which metal tubes are integrated as shown in FIG. 4 is obtained. In the heat exchanger 21, the outer surfaces 61, 63 of the first metal tube 47 and the opposing surfaces 65, 67 of the second metal tube 45 and the third metal tube 49 are fusion-bonded, and the side portions are elongated. A nugget 76 is continuously formed along the direction. A desired fluid flow path 53 is secured inside the first metal pipe 47. The heat exchanger 21 can be used in the form of a straight line as shown in FIG. 4, but may be used after being bent into a spiral shape as shown in FIG. In the case of the form shown in FIG. 1, the metal tubes 45, 47, 49 are bent so that the thickness direction thereof is in the radial direction of the spiral.

  Examples of resistance welding conditions include pressure applied by the roller electrodes 71 and 73, electrode shape, energization time, rest time, current value during welding, welding speed (feed speed), and the like. It is set as appropriate according to the intended use. In addition, in the resistance welding of this embodiment, the intermittent welding which repeats electricity supply and a pause may be sufficient, and the continuous welding which supplies electricity continuously may be sufficient.

  As described above, according to the manufacturing method of the present embodiment, the fluid channel 53 of the first metal tube 47 is filled with the filler having a larger electric resistance than the first metal tube 47, and the first metal tube 47. And the second metal tube 45 are resistance-welded, so that the filler serves to suppress deformation of the first metal tube 47 during welding, and the first metal tube 47 and the second metal tube are suppressed by suppressing the deformation. It is possible to perform welding while applying sufficient pressure to 45 in the thickness direction. As a result, it is possible to sufficiently secure the joint area between the metal tubes while sufficiently securing the fluid flow path 53 inside the first metal tube 47, and thus it is possible to suppress a decrease in the efficiency of heat exchange. In addition, this method is excellent in productivity because metal tubes can be joined continuously using resistance welding.

  Moreover, in this embodiment, since the filler is a granular heat resistant resin, it has appropriate fluidity. Thereby, it becomes easy to fill the first metal tube with the filler, and it is also easy to extract the filler from the metal tube after welding.

  Further, in the present embodiment, in the resistance welding process, the laminate is resistance welded in a state where the openings at both ends of the first metal tube 47 are closed, so that the filler flows out from the end of the first metal tube 47. Can be suppressed.

  In the present embodiment, since the second metal tube 45 and the third metal tube 49 are stacked on both sides of the first metal tube 47 in the thickness direction, the efficiency of heat exchange between the refrigerant and the fluid is further improved. be able to. Further, since the second metal tube 45 and the third metal tube 49 are multi-hole tubes in which a plurality of fluid flow paths 51 are formed along the longitudinal direction, the second metal tube 45 and the third metal tube 49 are connected to each other. The uneven flow of the flowing fluid can be suppressed, and the efficiency of heat exchange with the fluid flowing through the first metal tube 47 can be further improved.

(Second Embodiment)
FIG. 5: is sectional drawing which shows the manufacturing method of the heat exchanger concerning 2nd Embodiment of this invention. In the manufacturing method of the second embodiment, water is used as the filler. In addition, about the member similar to 1st Embodiment, the same code | symbol as 1st Embodiment is attached | subjected and description is abbreviate | omitted.

  As shown in FIG. 5, in the manufacturing method of the second embodiment, in the resistance welding process, the laminated body (the first metal tube 47, the second metal tube 45, and the third metal tube 49 arranged in a stacked manner) The direction is arranged in an oblique direction inclined from the vertical. The opening at the lower end of the first metal tube 47 is closed by a closing member (not shown). The fluid channel 53 of the first metal tube 47 is filled with water as a liquid filler.

  As a method of filling the fluid flow path 53 of the first metal pipe 47 with water, for example, as described above, water is introduced into the fluid flow path 53 from the opening at the upper end in a state where the laminate is disposed in an oblique direction. The method of pouring in is mentioned. After filling the fluid flow path 53 with water, the opening at the upper end may be closed by a closing member, or may remain open.

  When resistance welding is performed with the upper end opened, water may spill out from the upper end opening due to pressure applied by the roller electrodes 71 and 73 in the thickness direction. The amount of water that spills out is limited.

  When the opening at the upper end is closed by the closing member, the pressure in the fluid flow path 53 may be increased by the pressurization in the thickness direction by the roller electrodes 71 and 73. For example, the opening at the upper end It is preferable to provide a through-hole through which the inside and the outside of the fluid flow path 53 communicate with each other in a part of the closing member that closes the cover. Thereby, even when the pressure in the fluid flow path 53 increases, a part of water can be discharged from the through-hole.

  A pair of roller electrodes 71 and 73 are disposed on both sides in the thickness direction of the laminate. The rotating shafts 72 and 74 of the roller electrodes 71 and 73 are supported by two guide rails 91 and 92 arranged on both sides in the thickness direction of the laminate along the longitudinal direction of the laminate.

  A motor (not shown) is connected to each of the rotating shafts 72 and 74, and the motor is connected to a power supply device 79. The roller electrode 71 and the roller electrode 73 rotate in opposite directions. For example, in FIG. 5, the roller electrode 71 rotates clockwise and the roller electrode 73 rotates counterclockwise.

  The roller electrodes 71 and 73 slide along the guide rails 91 and 92 while maintaining a substantially constant distance between these roller electrodes. The guide rails 91 and 92 are configured so that the interval between the guide rails can be adjusted according to the thickness of the laminated body.

  As described above, in the second embodiment, the laminated body is resistance-welded while moving the roller electrodes 71 and 73 along the longitudinal direction of the laminated body in a state where the laminated body is arranged and fixed in an oblique direction. After the resistance welding of one laminate is completed, the roller electrodes 71 and 73 are returned to the starting point obliquely downward along the guide rails 91 and 92, and the next laminate is resistance welded. In addition, when resistance welding of the next laminated body is completed after resistance welding of one laminated body is completed, the resistance welding is performed obliquely upward without returning the roller electrodes 71 and 73 obliquely downward as described above. The next laminated body may be resistance-welded by moving the roller electrodes 71 and 73 downward from the bottom.

  As described above, according to the manufacturing method of the second embodiment, since the filler is water, it has high fluidity. This makes it easy to fill the first metal tube 47 with the filler, and also makes it easy to extract the filler from the first metal tube 47 after welding. Moreover, since the filler is liquid, the effect of cooling the laminate can be obtained. Thereby, it can suppress that the temperature of a laminated body rises too much with the heat which generate | occur | produces at the time of welding.

  In the second embodiment, the longitudinal direction of the laminated body is arranged in an oblique direction inclined from the vertical, and resistance welding is performed in a state where the opening at the lower end of the first metal tube 47 filled with the filler is closed. Thus, the liquid filler can be prevented from flowing out from the lower end of the first metal tube 47, and the horizontal area required at the manufacturing site can be reduced.

  In the second embodiment, since the roller electrodes 71 and 73 are moved in an oblique direction and resistance welding is performed, it is not necessary to move a long laminated body in an oblique direction. The vertical height can be reduced.

<Heat pump water heater>
Here, the heat pump type water heater 11 in which the heat exchanger 21 is used as a water heat exchanger for a water heater will be described. FIG. 6 is a configuration diagram showing the heat pump type hot water heater 11. As shown in FIG. 6, the heat pump type hot water heater 11 is used to boil low-temperature water by heat exchange between the refrigerant circuit 13 that circulates the refrigerant and the refrigerant in the refrigerant circuit 13 and store the high-temperature water in the tank 15. And a hot water storage circuit 17.

  The refrigerant circuit 13 includes a compressor 19, the above-described heat exchanger (water heat exchanger) 21, an expansion valve (decompression mechanism) 23, an evaporator 25, and a pipe connecting them. As the refrigerant circulating in the refrigerant circuit 13, for example, carbon dioxide is used. When carbon dioxide is used as the refrigerant, the refrigerant is compressed by the compressor 19 to a critical pressure or higher.

  The hot water storage circuit 17 includes a tank 15 in which water is stored, a water inlet pipe 27 that sends water from the tank 15 to the heat exchanger 21, and a hot water that returns water heated by heat exchange with the heat exchanger 21 to the tank 15. A pipe 29 and a pump 31 for circulating water in the hot water storage circuit 17 are provided.

  The water heater 11 includes a control unit 33 that controls the refrigerant circuit 13 and the hot water storage circuit 17. The control unit 33 drives the compressor 19 of the refrigerant circuit 13 and also drives the pump 31 of the hot water storage circuit 17, so that low-temperature water in the tank 15 passes through the water inlet pipe 27 from the water outlet provided at the bottom of the tank 15. It is sent to the heat exchanger 21. The low-temperature water sent to the heat exchanger 21 is heated in the heat exchanger 21 and returned to the tank 15 from a water inlet provided in the upper part of the tank 15 through the hot water piping 29. Thereby, in the tank 15, hot water is stored in the upper part, and the temperature of the water is lowered toward the lower part.

  The tank 15 includes a hot water supply pipe 35 for taking out the stored hot water from the upper part of the tank 15 and supplying hot water to a bathtub or the like, and a water supply pipe 37 for supplying low temperature water such as tap water to the bottom of the tank 15. I have.

  The direction in which the refrigerant and water flow in the heat exchanger 21 are opposite to each other as shown in FIG. Therefore, either refrigerant or water flows from the one end 41 side of the heat exchanger 21 shown in FIG. 1 toward the other end 43 side, and the other flows from the other end 43 side toward the one end 41 side. Thus, while the refrigerant and water pass through the heat exchanger 21, heat is exchanged between the water and the refrigerant, and the temperature of the water can be adjusted.

  Note that the present invention is not limited to the above-described embodiment, and various modifications and improvements can be made without departing from the spirit of the present invention. For example, in the above embodiment, the case where the second metal tube and the third metal tube are multi-hole tubes has been described as an example. However, these metal tubes are metal tubes having no partition like the first metal tube. There may be. In this case, the first metal pipe, the second metal pipe, and the third metal pipe are filled with a filler having an electric resistance larger than those of the metal pipes and resistance-welded. Thereby, while a filler plays the role which suppresses the deformation | transformation of the metal pipe at the time of welding, it can weld, applying sufficient pressure to the thickness direction with respect to each metal pipe by suppressing a deformation | transformation. Thereby, it is possible to sufficiently secure the bonding area between the metal tubes while sufficiently securing the flow paths inside the metal tubes.

  Moreover, although the case where the heat resistant resin was used as the granular filler was described as an example in the above embodiment, other granular fillers such as sand can also be used. For example, when sand is used as the granular filler, since the sand has a high hardness, deformation of the metal tube during welding can be further suppressed. As a result, a sufficient flow path inside the metal tube can be secured, and welding can be performed while applying a greater pressure to the first metal tube and the second metal tube in the thickness direction. The bonding area can be further increased.

  Moreover, in the said embodiment, although the 2nd metal pipe, the 1st metal pipe, and the 3rd metal pipe demonstrated as an example and demonstrated the form of 3 layers laminated | stacked in this order, a 2 layer form may be sufficient, Four or more layers may be used.

  Further, in the above embodiment, the case where each metal tube has a flat shape having a substantially rectangular cross section has been described as an example. However, for example, other shapes such as a shape having a cross section in which a side portion in the width direction is curved are described. It may be a flat shape.

  In the above embodiment, the case where the metal tubes are joined by fusion welding in which the outer surfaces of the metal tubes are locally melted in the vicinity of the boundary has been described as an example. Resistance welding may be performed in a state in which a molten metal having a lower melting point is disposed between the outer surface of the tube and the outer surface of the other metal tube.

  In the above embodiment, the case where water is used as the liquid filler has been described as an example. However, the liquid filler is not limited to water and may be other liquids.

  Moreover, in the said embodiment, when the liquid was used as a filler, the case where the laminated body was arrange | positioned in the diagonal direction inclined from the vertical was mentioned as an example, You may arrange | position a laminated body to a perpendicular direction. In this case, it is preferable that the laminated body is fixed and the roller electrode is moved upward or downward in the vertical direction. Also, when the laminated body is arranged in the vertical direction, it spills out from the opening at the upper end of the metal tube due to the pressure of the roller electrode during resistance welding as compared with the case where the laminated body is arranged in the oblique direction. The amount of water can be further reduced.

21 Heat exchanger 45 Second metal pipe 47 First metal pipe 49 Third metal pipe 51 Refrigerant flow path 53 Fluid flow path 71, 73 Roller electrode

Claims (9)

A method for manufacturing a heat exchanger for exchanging heat between fluids respectively flowing inside adjacent metal pipes,
The first metal pipe (47) having a flat shape with a width larger than the thickness and having a fluid flow path (53) formed therein along the longitudinal direction, and a flat shape with a width larger than the thickness A second metal pipe (45) having a shape and having a plurality of fluid flow paths (51) formed therein along the longitudinal direction, the longitudinal direction and the thickness direction of both being aligned in the same direction, the thickness direction. And laminating and arranging,
Filling the fluid flow path (53) of the first metal pipe (47) with a filler having a larger electric resistance than the first metal pipe (47);
The first metal tube (47) and the second metal tube (45) arranged in a stacked manner are arranged between a pair of roller electrodes (71, 73), and the pair of roller electrodes (71, 73) are arranged in the thickness direction. While applying pressure, the first metal tube (47) and the second metal tube (45) are moved relative to the pair of roller electrodes (71, 73) along the longitudinal direction so as to move the first metal tube (47). ) And the second metal pipe (45) by resistance welding,
And a step of removing the filler from the fluid flow path (53) after the resistance welding. A method for manufacturing a heat exchanger for exchanging heat between fluids respectively flowing inside adjacent metal pipes,
The first metal pipe (47) having a flat shape with a width larger than the thickness and having a fluid flow path (53) formed therein along the longitudinal direction, and a flat shape with a width larger than the thickness A second metal tube (45) having a shape and having a fluid channel (51) formed therein along the longitudinal direction is laminated in the thickness direction so that both the longitudinal direction and the thickness direction are aligned in the same direction. Arranging, and
Filling each fluid flow path of each of the first metal pipe (47) and the second metal pipe (45) with a filler having a larger electric resistance than these metal pipes;
The first metal tube (47) and the second metal tube (45) arranged in a stacked manner are arranged between a pair of roller electrodes (71, 73), and the pair of roller electrodes (71, 73) are arranged in the thickness direction. While applying pressure, the first metal tube (47) and the second metal tube (45) are moved relative to the pair of roller electrodes (71, 73) along the longitudinal direction so as to move the first metal tube (47). ) And the second metal pipe (45) by resistance welding,
And a step of removing the filler from the fluid flow path after the resistance welding.   The manufacturing method of the heat exchanger of Claim 1 or 2 whose said filler is sand.   The manufacturing method of the heat exchanger of Claim 1 or 2 whose said filler is a granular heat resistant resin.   The manufacturing method of the heat exchanger of Claim 1 or 2 whose said filler is a liquid.   The said 1st metal pipe (47) and a 2nd metal pipe (45) are resistance-welded in the said resistance welding process in the state which block | closed the opening of the both ends of the said metal pipe with which the said filler was filled. The manufacturing method of the heat exchanger in any one of -5.   In the resistance welding step, the longitudinal direction of the first metal pipe (47) and the second metal pipe (45) arranged in layers is arranged in the vertical direction or in an oblique direction inclined from the vertical, and the filler is filled. The first metal tube (47) and the second metal tube (45) are connected to the pair of roller electrodes (71, 73) in a state in which the opening of at least the lower end of the metal tube is closed. The method for manufacturing a heat exchanger according to claim 5, wherein the first metal tube (47) and the second metal tube (45) are resistance-welded by relatively moving in the longitudinal direction.   In the resistance welding step, the pair of roller electrodes (71, 73) are moved in the vertical direction or the oblique direction to resistance weld the first metal tube (47) and the second metal tube (45). Item 8. A method for manufacturing a heat exchanger according to Item 7. In the stacking and arranging step, the second metal tube (45), the first metal tube (47), and a flat shape having a width larger than the thickness are formed, and a plurality of fluid flow paths along the longitudinal direction. (51) and the third metal tube (49) formed therein is laminated in this thickness direction in this order,
In the resistance welding step, the first metal pipe (47), the second metal pipe (45) and the third metal pipe (49) are arranged between the pair of roller electrodes (71, 73) and resistance welding is performed. The manufacturing method of the heat exchanger of Claim 1.

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