Heat exchanger for gas appliances and method for manufacturing a heat exchanger for gas appliances

Abstract

This invention aims to prevent the installation of water passages in heat exchangers for gas appliances from being incorrectly positioned. [Solution] In the heat exchanger 10, the first water passage section 110 is provided with a first covering section 112, and the second water passage section 120 is provided with a second covering section 122. The side plate section 60 is provided with a first mark 71 and a second mark 71. The first covering section 112 is provided with a third mark 73, and the second covering section 122 is provided with a fourth mark 74. When the first covering section 112 is oriented correctly, the first mark 71 and the third mark 73 indicate a first normal indication, and when it is oriented incorrectly, the first mark 71 and the third mark 73 indicate a first abnormal indication. When the second covering section 122 is oriented correctly, the second mark 71 and the fourth mark 74 indicate a second normal indication, and when it is oriented incorrectly, the second mark and the fourth mark indicate a second abnormal indication.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a heat exchanger for gas appliances and a method of manufacturing a heat exchanger for gas appliances. BACKGROUND ART

[0002] Patent Document 1 discloses a latent heat heat exchanger. In the latent heat heat exchanger of Patent Document 1, the casing includes a cylindrical case body having openings on both sides produced by welding an upper case and a lower case, and a pair of side plates that close the openings. The inflow header and the outflow header are respectively arranged outside one of the side plates, and are respectively connected to the upstream end and the downstream end of the heat absorption pipe that is led out through an insertion hole provided in the one side plate. PRIOR ART DOCUMENTS PATENT DOCUMENTS

[0003] PATENT DOCUMENT 1 Japanese Unexamined Patent Application Publication No. 2017-26286 SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0004] In heat exchangers including the latent heat heat exchanger of Patent Document 1, a configuration in which a box-shaped water passage portion also referred to as an inflow header or an outflow header is provided at a side portion of a case is common. This water passage portion has a lid body provided with a water inlet and a water outlet. For example, in the latent heat heat exchanger of Patent Document 1, header lids are provided at the inflow header and the outflow header, and the header lid is provided with a connection port that is connected to an external water pipe.

[0005] In this type of heat exchanger, many of the outer edges of the lid bodies constituting the water passage portion have a rotationally symmetric shape. In such a configuration, when a worker attaches the lid body, there is a risk that the water passage portion may be attached in an incorrect posture that is not the normal posture, and if the water passage portion is attached in the incorrect posture, there is a concern that a defect caused by the improper arrangement may occur.

[0006] One of the purposes of this disclosure is to provide a technology that can prevent the installation of water passages in heat exchangers for gas appliances from being incorrectly positioned. [Means for solving the problem]

[0007] One of the disclosures is a heat exchanger for a gas appliance, A case comprising a main body portion configured in a cylindrical shape with at least one end in the left-right direction having an opening, and a side plate portion attached to the main body portion in a manner that closes the opening, Multiple heat transfer tubes housed within the aforementioned case, A first water passage is attached to the side plate and is a flow path that leads to either the inlet or outlet side of the plurality of heat transfer tubes, A second water passage is attached to the side plate and is a flow path that leads to the other of either the inlet side or the outlet side of the plurality of heat transfer tubes, It has, A heat exchanger for a gas appliance, wherein the space inside the case is configured as a space through which exhaust gas passes, The side plate portion is provided with a first hole, which is a hole for fixing either the inlet side or the outlet side of the plurality of heat transfer tubes, and a second hole, which is a hole for fixing the other either the inlet side or the outlet side of the plurality of heat transfer tubes. The first water passage is positioned to cover a plurality of the first holes and includes a first covering portion attached to the outer surface of the side plate portion opposite to the space inside the case, The second water-conducting portion is positioned to cover a plurality of the second holes and includes a second covering portion attached to the outer surface. The side plate portion is provided with a first mark and a second mark. The first covering portion is provided with a third mark, The second covering portion is provided with a fourth mark. When the first covering portion is positioned in the correct orientation relative to the side plate portion, the first mark and the third mark indicate a first normal indication; when it is positioned in the wrong orientation, the first mark and the third mark indicate a first abnormal indication. When the second covering portion is positioned in the correct orientation relative to the side plate portion, the second mark and the fourth mark indicate a second normal indication; when it is positioned in the wrong orientation, the second mark and the fourth mark indicate a second abnormal indication.

[0008] One of the disclosures is a method for manufacturing a heat exchanger for a gas appliance, A method for manufacturing a heat exchanger for a gas appliance, comprising: a case comprising a main body portion configured in a cylindrical shape with at least one end in the left-right direction configured as an opening; a side plate portion attached to the main body portion in a manner that closes the opening; a plurality of heat transfer tubes housed in the case; a first water passage portion attached to the side plate portion and being a passage that leads to either the inlet side or the outlet side of the plurality of heat transfer tubes; and a second water passage portion attached to the side plate portion and being a passage that leads to the other either the inlet side or the outlet side of the plurality of heat transfer tubes, wherein the space within the case is configured as a space through which exhaust gas passes, The side plate portion is provided with a plurality of first holes, which are holes for fixing either the inlet side or the outlet side of the plurality of heat transfer tubes, and a plurality of second holes, which are holes for fixing the other either the inlet side or the outlet side of the plurality of heat transfer tubes. The first water-conducting section is configured to include a first covering section which is a covering member, The second water-conducting portion is configured to include a second covering portion that is different from the first covering portion, A first mark and a second mark are provided on the side plate portion. A third mark is provided on the first covering portion, A fourth mark is provided on the second covering portion. On the outer surface of the side plate portion opposite to the space inside the case, the first covering portion is attached at a position that covers the plurality of first holes. The second water passing part is attached to a position on the outer surface part that covers the plurality of the second hole parts, When the first covering part is arranged in the correct orientation relative to the side plate part, the first mark and the third mark present a first normal indication, and when arranged in an incorrect orientation, the first mark and the third mark present a first abnormal indication, When the second covering part is arranged in the correct orientation relative to the side plate part, the second mark and the fourth mark present a second normal indication, and when arranged in an incorrect orientation, the second mark and the fourth mark present a second abnormal indication. [Effects of the Invention]

[0009] According to the technology of the present disclosure, in a heat exchanger for a gas appliance, it is possible to prevent the water passing part from being attached in an incorrect arrangement. [Brief Description of the Drawings]

[0010] [Figure 1] Figure 1 is an explanatory diagram schematically illustrating a water heater using the heat exchanger for a gas appliance according to the first embodiment. [Figure 2] Figure 2 is a plan view illustrating a structure that is part of the water heater of Figure 1, and is a site where an exhaust part is assembled to the heat exchanger for a gas appliance according to the first embodiment. [Figure 3] Figure 3 is a right side view of the structure of Figure 2. [Figure 4] Figure 4 is a left side view of the structure of Figure 2. [Figure 5] Figure 5 is a bottom view of the structure of Figure 2. [Figure 6] Figure 6 is a rear view of the structure of Figure 2. [Figure 7] Figure 7 is an exploded perspective view of the structure of Figure 2. [Figure 8] Figure 8 is an exploded perspective view showing the vicinity of the side plate part on one side of the structure of Figure 2 in an exploded state. [Figure 9]Figure 9 is a perspective view illustrating a heat exchanger for gas appliances according to the first embodiment, which exemplifies the heat exchanger forming part of the structure in Figure 2. [Figure 10] Figure 10 is a right side view of a configuration in which the side plate portion on one side and some components assembled to the side plate portion are omitted from the heat exchanger of Figure 9. [Figure 11] Figure 11 is a perspective view showing the lower case portion of the heat exchanger in Figure 9. [Figure 12] Figure 12 is a perspective view exemplifying a configuration in which the structure with a plurality of heat transfer tubes assembled to one side plate portion is removed from the main body portion, and the other side plate portion is removed from the main body portion, in the heat exchanger of Figure 9. [Figure 13] Figure 13 is a perspective view showing a structure that is part of the heat exchanger of Figure 9 and has a configuration in which a plurality of heat transfer tubes are assembled to one side plate portion. [Figure 14] Figure 14 is an exploded perspective view showing the structure of Figure 13 in an exploded state. [Figure 15] Figure 15 is a perspective view showing the main body portion and the side plate portion of the heat exchanger for gas appliances according to the first embodiment shown in Figure 9, separated from each other. [Figure 16] Figure 16 is an enlarged perspective view showing a part of the side plate portion of the heat exchanger in Figure 9 in an enlarged manner. [Figure 17] Figure 17 is an enlarged view showing an enlarged part of the configuration of the assembly formed by mutually assembling the side plate portion and the main body portion of the heat exchanger in Figure 9, as viewed from the rear side. [Figure 18] Figure 18 is a cross-sectional view partially and schematically showing a configuration obtained by cutting the assembly, in which the side plate portion of the heat exchanger in Figure 9 is assembled to the main body portion, along a cutting plane oriented perpendicular to the front-rear direction. [Figure 19] Figure 19 is a perspective view partially showing the assembly in which the side plate portion of the heat exchanger in Figure 9 is assembled to the main body portion. [Figure 20] Figure 20 is an explanatory diagram showing an example in which the side plate portion is attached in an orientation different from the normal orientation when manufacturing the heat exchanger of Figure 9. [Figure 21]Figure 21 is an explanatory diagram showing an example in which the first and second covering portions were installed in a different orientation than the standard orientation when manufacturing the heat exchanger shown in Figure 9. [Modes for carrying out the invention]

[0011] <First Embodiment> 1. Overview of water heaters Figure 1 illustrates a water heater 1 using a heat exchanger for a gas appliance according to the first embodiment. The water heater 1 has the function of heating tap water supplied from an external source to produce hot water. As shown in Figure 1, the water heater 1 has a combustion device 3, a heat exchanger 4, an exhaust 5, etc., inside the housing 2. In Figure 1, the housing 2 that houses the various parts is conceptually shown by a dashed line. The housing 2 is a box-shaped case made of metal material.

[0012] The combustion device 3 shown in Figure 1 is equipped with a gas burner. The combustion device 3 burns the gas supplied through a supply path (not shown) using the gas burner, producing exhaust gas. In the following description, the exhaust gas produced by the combustion of gas in the gas burner will also be referred to as combustion exhaust gas.

[0013] The heat exchanger section 4 shown in Figure 1 comprises a primary heat exchanger, a heat exchanger 9, and a secondary heat exchanger, a heat exchanger 10. The combustion exhaust passing through the heat exchanger section 4 passes through the respective cases that make up the heat exchanger 9 and the heat exchanger 10. Heat transfer tubes (not shown) are provided inside the heat exchanger 9, and water supplied from the outside flows through these tubes. The heat exchanger 9 transfers heat from the combustion exhaust to the water passing through the heat transfer tubes, mainly transferring sensible heat energy to the water passing through the heat transfer tubes. The heat exchanger 10 has a plurality of heat transfer tubes 80 as shown in Figures 7 and 8. The heat exchanger 10 shown in Figure 1 transfers heat from the combustion exhaust after passing through the heat exchanger 9 to the water passing through the plurality of heat transfer tubes 80, mainly transferring latent heat energy to the water passing through the plurality of heat transfer tubes 80.

[0014] 2. Overview of Heat Exchangers The following description relates to the heat exchanger 10. Figures 2 to 6 show a structure in which the exhaust section 5 is assembled to the heat exchanger 10. Figure 7 shows an exploded perspective view of the structure shown in Figure 2, etc. Figure 8 shows an exploded perspective view of the structure shown in Figure 2, etc., with the area near the side plate on one side in the left-right direction disassembled. Figure 9 shows a perspective view of the heat exchanger 10 according to the first embodiment. The heat exchanger 10 shown in Figure 9, etc. is a latent heat recovery type heat exchanger for gas appliances.

[0015] In this embodiment, the left-right direction, front-back direction, and up-down direction are defined. The left-right direction is the direction parallel to a predetermined first straight line. The front-back direction is the direction parallel to a predetermined second straight line perpendicular to the first straight line. The up-down direction is the direction parallel to a third straight line perpendicular to both the first and second straight lines. In the representative example shown in Figures 1 to 9, the direction in which the two side plate portions 60 and 69 of the heat exchanger 10 face each other is the left-right direction. Also, in the representative example, the thickness direction of the flat plate portion 61, which will be described later, is the left-right direction. Furthermore, in the multiple heat transfer tubes 80, the direction in which the multiple linear pipe portions 83, which are configured in a straight line, extend is the left-right direction. On the other hand, in the front plate portion 46, the thickness direction of the flat plate portion that constitutes the front surface is the front-back direction. Also, in the representative example, the vertical direction when the water heater 1 is installed is the up-down direction. In other words, in the representative example, the direction of the third straight line is the vertical direction. Furthermore, the longitudinal direction of the opening area of ​​the exhaust port 5A, that is, the direction in which the elongated hole constituting the exhaust port 5A extends, is the left-right direction as described above. In the representative example of water heater 1, the longitudinal direction of the water heater 1 when viewed in a plan view from directly above is the left-right direction.

[0016] As shown in Figure 3, the exhaust section 5 is attached to the front plate section 46, which is the front surface of the heat exchanger 10, from the front. The front plate section 46, which is configured as a flat plate, has an outlet 46Z formed as an elongated hole in the left-right direction. The rear plate section 48 is the rear surface of the heat exchanger 10. The rear plate section 48, which is configured as a flat plate, has an inlet 48Z formed as an elongated hole in the left-right direction. In the heat exchanger 10, exhaust gas that has flowed along the rear side of the heat exchanger 10 through a flow path (not shown) is introduced into the case 20 from the inlet 48Z provided in the rear plate section 48, as shown in Figure 6. Inside the case 20, the exhaust gas flows from the inlet 48Z towards the outlet 46Z provided in the front plate section 46, and this exhaust gas is discharged outside the case 20 from the outlet 46Z and flows into the exhaust section 5. An exhaust port 5A is provided at the front end of the exhaust section 5. The exhaust port 5A is positioned exposed in the space outside the water heater 1. The exhaust that flows from the outlet 46Z into the exhaust section 5 passes through the exhaust section 5 and is discharged to the front from the exhaust port 5A, and the exhaust that flows to the front from the exhaust port 5A is released into the space outside the water heater 1.

[0017] As shown in Figures 9 and 10, the heat exchanger 10 includes a box-shaped case 20. The space inside the case 20 is the space through which the exhaust gas described above passes. As shown in Figure 12, the case 20 includes a main body 30 and side plate sections 60 and 69. The main body 30 is configured as a cylindrical shape extending in the left-right direction. The right end, which is one end of the main body 30 in the left-right direction, is configured as an opening 36. The left end, which is the other end of the main body 30 in the left-right direction, is configured as an opening 37. As shown in Figure 10, a plurality of heat transfer tubes 80 are housed inside the case 20.

[0018] As shown in Figures 12 and 15, the main body 30 comprises an upper plate portion 42 positioned above the space through which combustion exhaust passes, a lower plate portion 44 positioned below the space, a front plate portion 46 positioned in front of the space, and a rear plate portion 48 positioned behind the space. The front plate portion 46 and the rear plate portion 48 are arranged along the vertical direction. The upper plate portion 42, the lower plate portion 44, the front plate portion 46, and the rear plate portion 48 are made of metal material.

[0019] The upper plate portion 42 has a plate-like upper surface and is located on the upper end side of the main body portion 30. The lower plate portion 44 has a plate-like lower surface and is located on the lower end side of the main body portion 30. The front plate portion 46 is a plate-like portion and is located on the front end side of the main body portion 30. The rear plate portion 48 is a plate-like portion and is located on the rear end side of the main body portion 30.

[0020] As shown in Figure 7, the main body 30 comprises an upper case portion 32 that forms part of the upper side of the case 20 and a lower case portion 34 that forms part of the lower side of the case 20. The upper case portion 32 comprises an upper plate portion 42, an upper portion 46A, and an upper portion 48A. The upper portion 46A is a plate-shaped overlapping portion provided on the rear side of the front plate portion 46 so as to overlap the front plate portion 46. The upper portion 48A is a plate-shaped overlapping portion provided on the front side of the rear plate portion 48 so as to overlap the rear plate portion 48. The upper plate portion 42 and the upper portions 46A and 48A are integrally constructed from a metal material. The upper portion 46A is bent downward from the front end of the upper plate portion 42, and the upper portion 48A is bent downward from the rear end of the upper plate portion 42. The lower case portion 34 has a lower plate portion 44 and a lower portion 46B. The lower portion 46B is a plate-shaped overlapping portion provided on the rear side of the front plate portion 46 and below the upper portion 46A, overlapping the front plate portion 46. The lower portion 48B is a plate-shaped overlapping portion provided on the front side of the rear plate portion 48 and below the upper portion 48A, overlapping the rear plate portion 48. The lower plate portion 44 and the lower portions 46B and 48B are integrally constructed from a metal material. The lower portion 46B is bent upward from the front end of the lower plate portion 44, and the lower portion 48B is bent upward from the rear end of the lower plate portion 44. The front wall portion of the case 20 is formed by the upper portion 46A and the lower portion 46B overlapping the front plate portion 46. The rear wall portion of the case 20 is formed by the upper portion 48A and the lower portion 48B overlapping the rear plate portion 48.

[0021] As shown in Figures 7 and 9, the upper plate portion 42 comprises an upper first plate portion 42A and an upper second plate portion 42B. The upper first plate portion 42A is a part of the upper plate portion 42 and is provided so as to extend upward and backward from the upper portion 46A. As shown in Figure 9, the upper first plate portion 42A extends in the left-right direction and has an inclined plate portion 42W that extends backward and upward from the upper end of the upper portion 46A. The inclined plate portion 42W of the upper first plate portion 42A is a flat plate portion, and the upper surface of this inclined plate portion 42W is an inclined surface that is inclined at a predetermined angle with respect to a horizontal plane, which is a virtual plane perpendicular to the vertical direction. In the representative example in Figure 9, the majority of the upper first plate portion 42A is composed of the inclined plate portion 42W. The upper second plate portion 42B is a part of the upper plate portion 42, which is integrally formed with the upper first plate portion 42A, and extends horizontally toward the rear while bending from the rear end portion of the upper first plate portion 42A. The upper second plate portion 42B extends in the left-right direction. Most or all of the upper second plate portion 42B is composed of a flat plate portion 42X having an upper surface parallel to the horizontal plane. The upper second plate portion 42B is integrally connected to the upper portion 48A. The upper portion 48A bends downward from the rear end portion of the upper second plate portion 42B.

[0022] As shown in Figures 7 and 11, the lower plate portion 44 comprises a lower first plate portion 44A and a lower second plate portion 44B. The lower first plate portion 44A is a part of the lower plate portion 44 and is provided so as to extend downward and forward from the lower portion 48B. As shown in Figure 7, the lower first plate portion 44A extends in the left-right direction and has an inclined plate portion 44W that extends forward and downward from the lower end of the lower portion 48B. The inclined plate portion 44W of the lower first plate portion 44A is a flat plate portion, and the upper surface of this inclined plate portion 44W is an inclined surface that is inclined at a predetermined angle with respect to the horizontal plane. In the representative example in Figure 7, the majority of the area of ​​the lower first plate portion 44A is composed of the inclined plate portion 44W. The lower second plate portion 44B is a part of the lower plate portion 44 which is integrally formed with the lower first plate portion 44A, and extends horizontally toward the front while bending from the front end portion of the lower first plate portion 44A. The lower second plate portion 44B extends in the left-right direction. A part of the lower second plate portion 44B is formed as a flat plate portion 44X having an upper surface parallel to the horizontal plane. The lower second plate portion 44B is integrally connected to the lower portion 46B. The lower portion 46B bends upward so as to rise from the front end portion of the lower second plate portion 44B.

[0023] As shown in Figures 7, 8, and 10, partition plates 91 and 92 are provided inside the case 20. Partition plate 91 is positioned between the multiple heat transfer tubes 80 and the upper plate portion 42. The rear end of partition plate 91 is fixed to the rear wall, and the front end of partition plate 91 is fixed to the front wall. Partition plate 91 is provided in a configuration that slopes downwards toward the front. Partition plate 92 is positioned between the multiple heat transfer tubes 80 and the lower plate portion 44. The rear end of partition plate 92 is fixed to the rear wall at a position lower than the rear end of partition plate 91. The front end of partition plate 92 is fixed to the lower plate portion 44. Partition plate 92 is provided in a configuration that slopes downwards toward the front. The space between partition plates 91 and 92 is the space in which the multiple heat transfer tubes 80 are arranged and is in communication with the inlet 48Z and outlet 46Z. The exhaust air introduced from inlet 48Z flows through the space between partition plates 91 and 92.

[0024] As shown in Figure 11, the lower second plate portion 44B is provided with a drain port 49 that guides the liquid flowing on the upper surface of the lower second plate portion 44B to the lower side of the lower second plate portion 44B. When condensate is generated inside the case 20 of the heat exchanger 10, this condensate flows down or falls within the case 20 and flows onto the partition plate 92 or the lower plate portion 44. As shown in Figure 10, the partition plate 92 has an inclined portion 92A that slopes downwards towards the front, with the upper surface being in a lower position towards the front, and a receiving portion 44Z, which is part of the lower plate portion 44, is located in front of the inclined portion 92A. The receiving portion 44Z is a part that constitutes the lower end of the lower plate portion 44 and is a part where the condensate that has flowed through the inclined portion 92A and the lower plate portion 44 collects. Specifically, in the lower second plate portion 44B, the receiving portion 44Z is configured as a recess that is recessed downwards from the flat plate portion 44X. The receiving portion 44Z, which is a recess, has the drain port 49 at its lowest position, and the upper surface around the drain port 49 within the receiving portion 44Z is an inclined surface that becomes higher as it moves away from the drain port 49. Therefore, the drain that flows into the receiving portion 44Z flows towards the drain port 49 within the receiving portion 44Z, and the drain that reaches the drain port 49 flows downward from the drain port 49. The drain port 49 is formed by drawing at the lower end of the receiving portion 44Z. The drain port 49 is formed integrally with the lower second plate portion 44B. In representative examples such as Figures 9 and 10, a pipe portion 78 communicating with the drain port 49 is provided, and liquids such as drain discharged through the drain port 49 are discharged to the outside via the pipe portion 78.

[0025] As shown in Figures 9 and 12, the side plate portion 60 and the side plate portion 69 are attached to the main body portion 30. The side plate portion 60 is attached to the main body portion 30 in a manner that closes the opening 36. The side plate portion 69 is attached to the main body portion 30 in a manner that closes the opening 37.

[0026] As shown in Figures 10 and 12, multiple heat transfer tubes 80 are housed inside the case 20. The heat transfer tubes 80 extend in a meandering manner along a virtual plane in a predetermined direction. The multiple heat transfer tubes 80 share a common shape with each other. In the representative examples shown in Figures 10 and 14, the multiple heat transfer tubes 80 are arranged in a stacked manner, forming multiple stages of flow paths. The heat transfer tube 80 has a first connection portion 81, a second connection portion 82, multiple (four in the representative example) straight pipe portions 83, and at least one (three in the representative example) bent portion 84. The first connection portion 81 is a portion provided on one end of the heat transfer tube 80 and is inserted into the first hole portion 58. The second connection portion 82 is a portion provided on the other end of the heat transfer tube 80 and is inserted into the second hole portion 59. In the representative examples shown in Figures 13 and 14, a first connection portion 81 is provided on the front and right end side of each heat transfer tube 80, and a second connection portion 82 is provided on the rear and right end side. The first connection portion 81 and the second connection portion 82 of each of the multiple heat transfer tubes 80 are attached to the first hole 58 and the second hole 59 at the corresponding heights. For example, the first connection portion 81 of the uppermost heat transfer tube 80 is attached to the uppermost first hole 58 of the multiple first holes 58 provided in the side plate portion 60. The second connection portion 82 of the uppermost heat transfer tube 80 is attached to the uppermost second hole 59 of the multiple second holes 59. Similarly, the first connection portion 81 of the second highest heat transfer tube 80 is attached to the second highest first hole 58 of the multiple first holes 58. The second connection portion 82 of the heat transfer tube 80, which is the second highest from the top, is attached to the second highest of the multiple second holes 59. As shown in Figures 12 and 13, when the multiple heat transfer tubes 80 are attached to the side plate portion 60, the space inside each first connection portion 81 of the multiple heat transfer tubes 80 is connected to the space inside the first water passage portion 110, and the space inside each second connection portion 82 of the multiple heat transfer tubes 80 is connected to the space inside the second water passage portion 120. Water flows between each first connection portion 81 and the first water passage portion 110, and water flows between each second connection portion 82 and the second water passage portion 120. In each heat transfer tube 80, water entering from one of the first connection portion 81 and the second connection portion 82 flows to the other.

[0027] 3. Detailed structure near the side panel 60 As shown in Figures 12 to 14, the side plate portion 60 is the part to which multiple heat transfer tubes 80 are fixed. The side plate portion 60 is also the part to which the first water passage portion 110 and the second water passage portion 120 are fixed. As shown in Figures 15 and 16, the side plate portion 60 is provided with a plate-shaped portion 61, a rising portion 62 rising from the outer edge of the plate-shaped portion 61, and an outer edge portion 64 protruding from the end of the rising portion 62. The side plate portion 60 is made of a metal material.

[0028] As shown in Figure 14, the plate-like portion 61 is a part that is made up of a flat metal plate of a predetermined thickness. In this embodiment, the thickness direction of the plate-like portion 61 is the left-right direction. The plate-like portion 61 is provided with a plurality of first holes 58 and a plurality of second holes 59. Each of the plurality of first holes 58 and the plurality of second holes 59 is made up of a through hole that penetrates the plate-like portion 61 in the thickness direction. The plurality of first holes 58 are holes to which one part of the plurality of heat transfer tubes 80, either the inlet side or the outlet side, is fixed. The plurality of second holes 59 are holes to which the other part of the plurality of heat transfer tubes 80, either the inlet side or the outlet side, is fixed. In a typical example, the plurality of first holes 58 are provided in front of the center position in the front-rear direction of the plate-like portion 61, and the plurality of second holes 59 are provided behind the center position in the front-rear direction of the plate-like portion 61.

[0029] As shown in Figure 15, one end of the inner surface 39 of the main body 30 in the left-right direction is the inner edge of the opening 36. The inner surface 39 is the inner wall portion that constitutes the surface of the main body 30 facing the internal space, and is the part that constitutes the inner circumferential surface of the cylindrical main body 30. The inner circumferential surface of the main body 30 is the inner surface of the cylindrical main body 30, and is the inner wall surface. One end of the outer surface 38 of the main body 30 in the left-right direction is the outer circumferential edge of the opening 36. The outer circumferential edge of the opening 36 is the part that constitutes the outer edge of the opening 36. The outer surface 38 is the part that constitutes the outer circumferential surface of the cylindrical main body 30, and is the outer wall portion. The outer circumferential surface of the main body 30 is the outer surface of the main body 30, and is the outer wall surface opposite to the internal space inside the main body 30. In a typical example, the opening 36 is formed by the end of the front wall of case 20, the end of the upper plate 42, the end of the rear wall of case 20, and the end of the lower plate 44. Specifically, the opening 36 is formed by one end in the left-right direction of the upper case portion 32 and one end in the left-right direction of the lower case portion 34, as shown in Figure 7.

[0030] As shown in Figures 16 and 18, the rising portion 62 of the side plate portion 60 is configured in an annular shape so as to rise up on one side in the thickness direction of the plate-like portion 61. In the example of Figures 15 and 16, one side in the thickness direction of the plate-like portion 61 is one side in the left-right direction, specifically the right side of the heat exchanger 10. That is, the rising portion 62 is configured to rise up to the right from the plate-like portion 61, and is configured in an annular shape overall. The rising portion 62 is the part that fits into the inner circumference 30A (Figures 15 and 18) on one side in the left-right direction of the main body portion 30.

[0031] The outer edge portion 64 of the side plate portion 60 is configured to protrude outward in an annular shape from the end opposite to the side connected to the plate-like portion 61 of the rising portion 62. In the example of Figures 15 and 16, the end opposite to the side connected to the plate-like portion 61 of the rising portion 62 is the end on one side in the left-right direction of the rising portion 62, specifically the right end of the rising portion 62. As shown in Figures 17 to 19, the outer edge portion 64 has a protruding portion 65 that protrudes outward in an annular shape beyond the outer peripheral edge of the opening 36. A part of the outer edge portion 64 overlaps with the opening 36 on the left and right sides so as to cover the opening 36 from one side in the left-right direction. The protruding portion 65 is the part of the outer edge portion 64 that protrudes outward so as not to overlap with the opening 36 on the left and right sides.

[0032] As shown in Figures 17 to 19, the side plate portion 60 and the main body portion 30 are joined on the outside of the rising portion 62, with the other side surface portion 64A of the outer edge portion 64 in the left-right direction and the opening 36 facing and in contact with it. For example, the surface portion 64A of the outer edge portion 64 and the main body portion 30 are joined by welding with the surface portion 64A of the outer edge portion 64 in annular contact with the opening 36. More specifically, the corner portion 90, which is formed by the outer surface portion 38 of the main body portion 30 and the surface portion 64A of the protruding portion 65, is designated as the welding site where welding is performed. In a typical example, the surface portion 64A of the outer edge portion 64 and the main body portion 30 are joined by welding with the surface portion 64A of the outer edge portion 64 in annular contact with the opening 36. The welding of the surface portion 64A and the main body portion 30 may be a known fusion welding method, a known pressure welding method, or a known brazing method.

[0033] In this embodiment, as shown in Figure 3, the shape of the rising portion 62 of the side plate portion 60 is rotationally symmetric with respect to the central axis G in the left-right direction. Specifically, the shape of the outer periphery of the side plate portion 60 is rotationally symmetric with respect to the central axis G in the left-right direction. The central axis G is a virtual axis extending in the thickness direction of the plate-like portion 61, and is the axis of the center position in the longitudinal and short-side directions of the side plate portion 60. In the examples of Figures 3 and 20, the central axis G is also the axis of the center position in the front-rear and vertical directions of the side plate portion 60. The shape of the rising portion 62 of the side plate portion 60 remains the same as the shape in the normal configuration even when the side plate portion 60 is rotated 180 degrees around the central axis G from the normal configuration as shown in Figure 3. Specifically, the shape of the outer periphery of the side plate portion 60 remains the same as the shape in the normal configuration as shown in Figure 20, even when the side plate portion 60 is rotated 180 degrees around the central axis G from the normal configuration as shown in Figure 3. The outer periphery of the side plate portion 60 is composed of an annular rising portion 62 and an annular outer edge portion 64. Due to this configuration, even if the side plate portion 60 is rotated 180 degrees around the central axis G from its normal state as shown in Figure 3, the shapes of the rising portion 62 and the outer edge portion 64 become the same as before the rotation and as in the normal state, making it possible for the side plate portion 60 to fit into the main body portion 30 as shown in Figure 20. In other words, there is a concern that the side plate portion 60 may be incorrectly positioned in an incorrect orientation, as shown in Figure 20. Therefore, as shown in Figure 3, the side plate portion 60 is provided with a mark 70 that identifies at least one of the front, back, top, or bottom sides of the side plate portion 60. In the representative example shown in Figure 3, the pointed end of the mark 70 indicates the front side of the side plate portion 60, and in the normal arrangement as shown in Figure 3, the side indicated by the pointed end of the mark 70 is the front side of the heat exchanger 10. On the other hand, in the incorrect configuration shown in Figure 20, the pointed end of the mark 70, which should indicate the front side of the side plate 60, is instead pointing to the rear side of the heat exchanger 10. In other words, the mark 70 is not facing forward, which is the correct orientation, but is facing backward, which is the incorrect orientation, clearly indicating that the side plate 60 is incorrectly positioned.

[0034] 4. Structure of the water passage As shown in Figures 3, 9, and 12, a first water passage 110 and a second water passage 120 are fixed to the side plate portion 60. The first water passage 110 is a flow path leading to one of the inlet or outlet portions of the plurality of heat transfer tubes 80. The second water passage 120 is a flow path leading to the other of the inlet or outlet portions of the plurality of heat transfer tubes 80.

[0035] As shown in Figure 14, the first water-conducting section 110 comprises a first fixing section 114 and a first covering section 112. The first fixing section 114 is made of a metal material and is fixed to the side plate section 60 by known fixing methods such as brazing or welding. The first fixing section 114 is provided with a plurality of third holes 114A corresponding to a plurality of first holes 58, and is fixed so that each first hole 58 and each third hole 114A are in communication with each other. Specifically, the plate section 114B, which is a part of the first fixing section 114 and is provided with the third holes 114A, is fixed so that it overlaps with the parts of the plate-like section 61 near the plurality of first holes 58. The first covering section 112 is fixed to the first fixing section 114 by known fixing methods such as brazing or welding. The first covering portion 112 is positioned to cover the plurality of first holes 58 and is indirectly attached to the outer surface portion 60A of the side plate portion 60 via the first fixing portion 114. The first water passage portion 110 is configured as a box body in which the first fixing portion 114 and the first covering portion 112 are joined together. In the box body configured as the first water passage portion 110, each third hole portion 114A is a hole that leads to the main body portion 30 side, and the hole portion 112A is a hole that leads to the outside of the heat exchanger 10. The inside of the first water passage portion 110 is a liquid passage region, and liquid flows from one side to the other between each third hole portion 114A and hole portion 122A. The outer surface portion 60A is the outer surface portion of the side plate portion 60 (opposite the internal space of the case 20).

[0036] As shown in Figure 14, the second water passage section 120 comprises a second fixing section 124 and a second covering section 122. The second fixing section 124 is made of a metal material and is fixed to the side plate section 60 by known fixing methods such as brazing or welding. The second fixing section 124 is provided with a plurality of fourth holes 124A corresponding to a plurality of second holes 59, and is fixed so that each second hole 59 and each fourth hole 124A are in communication with each other. Specifically, the plate section 124B, which is the part that constitutes the second fixing section 124 and is provided with the fourth holes 124A, is fixed so that it overlaps with the parts of the plate-like section 61 near the plurality of second holes 59. The second covering section 122 is fixed to the second fixing section 124 by known fixing methods such as brazing or welding. The second covering portion 122 is positioned to cover the multiple second holes 59 and is indirectly attached to the outer surface portion 60A of the side plate portion 60 via the second fixing portion 124. The second water passage portion 120 is formed as a box body by joining the second fixing portion 124 and the second covering portion 122. In the box body formed as the second water passage portion 120, each fourth hole portion 124A is a hole that leads to the main body portion 30, and the hole portion 122A is a hole that leads to the outside of the heat exchanger 10. The inside of the first water passage portion 110 is the liquid passage region.

[0037] As shown in Figures 8 and 14, the first covering portion 112 is provided with a hole 112A that allows water to flow between the inside and outside of the first water passage portion 110. The second covering portion 122 is provided with a hole 112A that allows water to flow between the inside and outside of the second water passage portion 120. An annular cylindrical portion 131 that serves as a water outlet or inlet is attached to the hole 112A. A packing 141 is sandwiched between the hole 112A and the cylindrical portion 131. An annular cylindrical portion 132 that serves as a water outlet or inlet is attached to the hole 122A. A packing 142 is sandwiched between the hole 122A and the cylindrical portion 132.

[0038] In this embodiment, as shown in Figure 8, the first fixing part 114 is configured in a box shape with a ring-like structure in which the peripheral wall part 114C rises from the plate part 114B so as to one side in the left-right direction. Specifically, it is a box shape with one side in the left-right direction open and a hole formed in the plate part 114B that forms the bottom. In contrast, the first covering part 112 is configured in a box shape with a ring-like structure in which the peripheral wall part 112C rises from the plate part 112B so as to the other side in the left-right direction. Specifically, it is a box shape with the other side in the left-right direction open and a hole provided in the plate part 112B that forms the bottom. In this configuration, the first covering part 112 is attached so as to fit inside the peripheral wall part 114C of the first fixing part 114. Specifically, the peripheral wall portion 112C is fitted inside the peripheral wall portion 114C, and the first covering portion 112 is attached to the first fixing portion 114 such that the plate portion 112B covers the multiple third holes 114A.

[0039] In this configuration, as shown in Figures 3 and 21, the outer edge portion 112Z of the first covering portion 112 has a shape that is rotationally symmetric with respect to the central axis K (Figure 21) in the left-right direction. Specifically, the shape of the outer edge portion 112Z in the normal arrangement as shown in Figure 3 is the same as the shape of the outer edge portion 112Z in the irregular arrangement obtained by rotating the first covering portion 112 by 180 degrees around the central axis K from the normal arrangement in Figure 3. Figure 21 shows the first covering portion 112 in such an irregular arrangement. The central axis K is a virtual axis in the thickness direction of the plate portion 112B and is the axis of the center position in the longitudinal and transverse directions of the first covering portion 112.

[0040] Similarly, as shown in Figures 3 and 21, the outer edge portion 122Z of the second covering portion 122 has a shape that is rotationally symmetric with respect to the central axis L in the left-right direction (Figure 21). Specifically, the shape of the outer edge portion 122Z in the normal arrangement as shown in Figure 3 is the same as the shape of the outer edge portion 122Z in the irregular arrangement obtained by rotating the second covering portion 122 by 180 degrees around the central axis L from the normal arrangement in Figure 3. Figure 21 shows the second covering portion 122 in such an irregular arrangement. Note that the central axis L is a virtual axis in the thickness direction of the plate portion 122B and is the axis of the center position in the longitudinal and transverse directions of the second covering portion 122.

[0041] Because of this configuration, even if the first covering portion 112, as shown in Figure 3, rotates 180 degrees around the central axis K (Figure 21), the shape of the outer edge portion 112Z after rotation (Figure 21) is the same as the shape of the outer edge portion 112Z before rotation (Figure 3), and the rotated first covering portion 112 fits into the first fixing portion 114 as shown in Figure 21. Similarly, even if the second covering portion 122, as shown in Figure 3, rotates 180 degrees around the central axis L, the shape of the outer edge portion 122Z after rotation (Figure 21) is the same as the shape of the outer edge portion 122Z before rotation (Figure 3), and the rotated second covering portion 122 fits into the second fixing portion 124 as shown in Figure 21. Furthermore, the first covering portion 112 and the second covering portion 122 have the same common shape. As shown in Figure 3, the first covering portion 112 and the second covering portion 122 are arranged in opposite directions to each other.

[0042] The side plate portion 60 is provided with a first mark 71 and a second mark 72. The first mark 71 is a directional mark on the side plate portion 60. The second mark 72 is a directional mark on the side plate portion 60. The first covering portion 112 is provided with a third mark 73. The second covering portion 122 is provided with a fourth mark 74. The third mark 73 is a directional mark on the first covering portion 112. The fourth mark 74 is a directional mark on the second covering portion 122. In a typical example, the first mark 71, the second mark 72, the third mark 73, and the fourth mark 74 all have the shape of the letter "V", and the side pointed to by the corner of the "V" indicates the direction indicated by the mark. Specifically, the first mark 71, the second mark 72, the third mark 73, and the fourth mark 74 all have two straight sections that form the letter "V," with one end of each straight section separated from the other and the other end connected to form a corner. The first mark 71 and the third mark 73 are both in a position where the corner of the "V" is pointed downwards, that is, the side that the corner of the "V" points downwards is the correct orientation. The second mark 72 and the fourth mark 74 are both in a position where the corner of the "V" is pointed upwards, that is, the side that the corner of the "V" points upwards is the correct orientation. The first mark 71 is positioned closer to the multiple first holes 58 than the second mark 72 in the side plate section 60, and closer to the first fixing section 114 than the second mark 72. In the example shown in Figure 3, the first fixing portion 114 and the first covering portion 112 are provided in front of the center position of the side plate portion 60 in the front-rear direction. The first mark 71 is also provided in front of the center position of the side plate portion 60 in the front-rear direction. The second mark 72 is positioned closer to the multiple second holes 59 than the first mark 71 on the side plate portion 60, and closer to the second fixing portion 124 than the first mark 71. In the example shown in Figure 3, the second fixing portion 124 and the second covering portion 122 are provided behind the center position of the side plate portion 60 in the front-rear direction. The second mark 72 is also provided behind the center position of the side plate portion 60 in the front-rear direction.

[0043] As shown in Figure 3, when the side plate portion 60 is installed in the correct position and the first covering portion 112 is installed in the correct orientation relative to the side plate portion 60, the first mark 71 and the third mark 73 indicate the first normal indication. When the side plate portion 60 is installed in the correct position and the second covering portion 122 is installed in the correct orientation relative to the side plate portion 60, the second mark 72 and the fourth mark 74 indicate the second normal indication. In the example in Figure 3, when the first covering portion 112 is installed in the correct orientation relative to the side plate portion 60, the first mark 71 and the third mark 73 are positioned to point to the same side. Specifically, in the first normal indication, both the first mark 71 and the third mark 73 are positioned so that their sharp corners face downwards. When the second covering portion 122 is installed in the correct orientation relative to the side plate portion 60, the second mark 72 and the fourth mark 74 are positioned to point to the same side. Specifically, in the second normal display, both the second mark 72 and the fourth mark 74 are positioned so that their sharp corners face upwards.

[0044] On the other hand, as shown in Figure 21, if the side plate portion 60 is installed in the correct position, but the first covering portion 112 is installed in the wrong orientation relative to the side plate portion 60 (specifically, upside down), the first mark 71 and the third mark 73 indicate a first abnormality. In the example in Figure 21, when the first covering portion 112 is installed in the wrong orientation relative to the side plate portion 60, the first mark 71 and the third mark 73 are positioned to point to different sides. In the first abnormality indication in Figure 21, the first mark 71 is positioned with its sharp corner facing downwards, and the third mark 73 is positioned with its sharp corner facing upwards, so they are facing opposite directions. As shown in Figure 21, if the side plate portion 60 is installed in the correct position, but the second covering portion 122 is installed in the wrong orientation relative to the side plate portion 60, the second mark 72 and the fourth mark 74 indicate a second abnormality. In the example shown in Figure 21, when the second covering portion 122 is installed in the wrong orientation relative to the side plate portion 60, the second mark 72 and the fourth mark 74 are positioned to point to different sides. In the second abnormal indication in Figure 21, the second mark 72 is positioned with its sharp corner facing upwards, and the fourth mark 74 is positioned with its sharp corner facing downwards, so they are facing opposite directions.

[0045] 5. Manufacturing method The heat exchanger 10 described above can be manufactured by the following manufacturing method. When manufacturing the heat exchanger 10, a preparation process is carried out to prepare the components shown in Figures 7 and 8. In this preparation process, when preparing the components that make up the heat exchanger 10, each component can be manufactured using known metalworking methods. When manufacturing each component, for example, when manufacturing the side plate portion 60, it is configured in the shape shown in Figure 15. Specifically, a side plate portion forming process is carried out to form the side plate portion 60 such that the plate-shaped portion 61, the rising portion 62, and the outer edge portion 64 shown in Figures 15 and 16 are formed by known metalworking methods. More specifically, in the side plate portion forming process, the side plate portion 60 is formed such that the plate-shaped portion 61 has a plurality of first holes 58, which are holes for fixing either the inlet side or the outlet side of the plurality of heat transfer tubes 80, and a plurality of second holes 59, which are holes for fixing either the inlet side or the outlet side of the plurality of heat transfer tubes 60. Furthermore, in this side plate forming process, a first mark 71 and a second mark 72 are formed on the side plate portion 60. A known metalworking method capable of forming these marks can be suitably used to provide the first mark 71 and the second mark 72 on the side plate portion 60.

[0046] On the other hand, a water passage forming process is carried out to form a first water passage 110 and a second water passage 120. In the water passage forming process, the first water passage 110 is formed to include a first covering portion 112, which is a covering member, and a first fixing portion 114 for attaching the first covering portion 112, and the second water passage 120 is formed to include a second covering portion 122, which is different from the first covering portion, and a second fixing portion 124 for attaching the second covering portion 122. In the water passage forming process, the first covering portion 112 and the first fixing portion 114 with the shapes described above, and the second covering portion 122 and the second fixing portion 124 with the shapes described above are formed. For example, in the water passage forming process, the first water passage 110 and the second water passage 120 are formed such that a third mark 73 is provided on the first covering portion 112 and a fourth mark 74 is provided on the second covering portion 122. In the water passage formation process, after the first covering portion 112, first fixing portion 114, second covering portion 122, and second fixing portion 124 shown in Figures 8 and 14 are formed, the first fixing portion 114 is fixed to a predetermined position (a position where each hole 114A and each first hole 58 are in communication), and the second fixing portion 124 is fixed to a predetermined position on the plate-like portion 61 (a position where each hole 124A and each second hole 59 are in communication). Also in the water passage formation process, after the first covering portion 112, first fixing portion 114, second covering portion 122, and second fixing portion 124 are formed, the first covering portion 112 is fixed to the first fixing portion 114, and the second covering portion 122 is fixed to the second fixing portion 124. Thus, in the water passage formation process, the first covering portion 112 is attached to the outer surface portion 60A of the side plate portion 60 opposite to the space inside the case 20, at a position that covers the plurality of first holes 58, and the second water passage portion 122 is attached at a position that covers the plurality of second holes 59. The fixing of the first fixing portion 114 and the second fixing portion 124 to the plate-shaped portion 60, and the fixing of the first covering portion 112 and the second covering portion 122 to the first fixing portion 114 and the second fixing portion can be done by known fixing methods such as brazing or welding. The fixing of the first fixing portion 114 and the second fixing portion 124 to the plate-shaped portion 60 may be done before, after, or at the same time as the fixing of the first covering portion 112 and the second covering portion 122 to the first fixing portion 114 and the second fixing portion.A structure like that shown in Figure 12 is formed by attaching a plurality of heat transfer tubes 80, cylindrical sections 131, 132, and packings 141, 142 to the side plate section 60, the first water passage section 110, and the second water passage section 120 before, after, or at the same time as the formation of these joints.

[0047] The main body 30 and side plate 69 described above can be constructed using known metalworking methods and connecting methods to achieve the configuration of the main body 30 and side plate 69 described above (see Figure 12, etc.). Then, one opening of the cylindrical main body 30 is closed by the side plate 69, and the other opening is closed by the side plate 60 on which the multiple heat transfer tubes 80 and the water passages are arranged. The side plate 60 and 69 are then joined to the main body 30 by the welding method described above to obtain a heat exchanger 10 as shown in Figure 9, etc.

[0048] In this manufacturing method, when attaching the first covering portion 112 to the side plate portion 60 during the manufacturing process described above, if the first covering portion 112 is positioned in the correct orientation relative to the side plate portion 60, the first mark 71 and the third mark 73 indicate a first normal indication, and if it is positioned in the wrong orientation, the first mark 71 and the third mark 73 indicate a first abnormal indication. Furthermore, when attaching the second covering portion 122 to the side plate portion 60, if the second covering portion 122 is positioned in the correct orientation relative to the side plate portion 60, the second mark 72 and the fourth mark 74 indicate a second normal indication, and if it is positioned in the wrong orientation, the second mark 72 and the fourth mark 74 indicate a second abnormal indication.

[0049] 6. Examples of effects The following explanation concerns an example of the effects of this configuration. In the heat exchanger 10, the first water passage section 110, which is attached to the side plate section 60, is equipped with a first covering section 112. The first covering section 112 is positioned to cover a plurality of first holes 58. The second water passage section 120, which is attached to the side plate section 60, is equipped with a second covering section 122. The second covering section 122 is positioned to cover a plurality of second holes 59. The side plate section 60 is provided with a first mark 71 and a second mark 72. The first covering section 112 is provided with a third mark 73. The second covering section 122 is provided with a fourth mark 74. When the first covering section 112 is attached to the side plate section 60 in the correct orientation, the first mark 71 and the third mark 73 indicate a first normal indication, and when it is attached in the wrong orientation, the first mark 71 and the third mark 73 indicate a first abnormal indication. When the second covering portion 122 is installed in the correct orientation relative to the side plate portion 60, the second mark 72 and the fourth mark 74 indicate a second normal indication, and when it is installed in the wrong orientation, the second mark and the fourth mark indicate a second abnormal indication. With this configuration, the operator can easily confirm whether the first covering portion 112 and the second covering portion 122 are installed in the correct orientation by looking at the mark indication. Therefore, this heat exchanger 10 makes it easy to prevent the first covering portion 112 and the second covering portion 122 from being installed in the wrong orientation.

[0050] In the heat exchanger 10, when the first covering portion 112 is installed in the correct orientation relative to the side plate portion 60, the first mark 71 and the third mark 73 are positioned to indicate the same side. When it is installed in the wrong orientation, the first mark 71 and the third mark 73 are positioned to indicate different sides. Therefore, when installing the first covering portion 112, the worker can easily visually confirm whether it is installed in the correct orientation. Similarly, when installing the second covering portion 122 in the correct orientation relative to the side plate portion 60, the second mark 72 and the fourth mark 74 are positioned to indicate the same side. When it is installed in the wrong orientation, the second mark 72 and the fourth mark 74 are positioned to indicate different sides. Therefore, when installing the second covering portion 122, the worker can easily visually confirm whether it is installed in the correct orientation.

[0051] The first mark 71 is positioned closer to the multiple first holes 58 than the second mark 72 on the side plate portion 60. The second mark 72 is positioned closer to the multiple second holes 59 than the first mark 71 on the side plate portion 60. In this heat exchanger 10, because the first mark 71 is positioned closer to the multiple first holes 58, when the first covering portion 112 is attached, the third mark 73 and the first mark 71 are in a closer relationship, making it easier to confirm whether it is a first normal indication or a first abnormal indication. Similarly, because the second mark 72 is positioned closer to the multiple second holes 59, when the second covering portion 122 is attached, the fourth mark 74 and the second mark 72 are in a closer relationship, making it easier to confirm whether it is a second normal indication or a second abnormal indication.

[0052] The outer edge 112Z of the first covering portion 112 has a shape that is rotationally symmetrical with respect to the central axis in the left-right direction. The outer edge 122Z of the second covering portion 122 has a shape that is rotationally symmetrical with respect to the central axis in the left-right direction. In such a configuration, the first covering portion 112 and the second covering portion 122 are prone to being positioned in the wrong orientation, so the above-described features are highly effective.

[0053] In the heat exchanger 10, the first covering portion 112 and the second covering portion 122 have the same common shape. This heat exchanger 10 allows for the commonization of parts, and in this common configuration, the correct or incorrect placement of either the first covering portion 112 or the second covering portion 122 can be indicated.

[0054] <Other Embodiments> This disclosure is not limited to the embodiments described above and in the drawings. For example, any combination of the features of the embodiments described above or below is possible as long as it does not contradict each other. Furthermore, any feature of the embodiments described above or below may be omitted unless explicitly stated as essential. Moreover, the embodiments described above may be modified as follows.

[0055] In the representative example of the above embodiment, the first water passage is the inlet side water passage and the second water passage is the outlet side water passage; however, the first water passage may be the outlet side water passage and the second water passage may be the inlet side water passage.

[0056] In the representative example of the above-described embodiment, the first normal indication and the second normal indication are shown as in Figure 3, but the invention is not limited to this example. For example, in the case of the first normal indication, the first mark on the side plate portion 60 and the third mark on the first covering portion 112 may be close together, and in the case of the first abnormal indication, the first mark on the side plate portion 60 and the third mark on the first covering portion 112 may be spaced apart. Similarly, in the case of the second normal indication, the second mark on the side plate portion 60 and the fourth mark on the second covering portion 122 may be close together, and in the case of the second abnormal indication, the second mark on the side plate portion 60 and the fourth mark on the second covering portion 122 may be spaced apart. In this case, the first, second, third, and fourth marks may have a function to indicate direction as in the above embodiment, but they may also not have a function to indicate direction (for example, a circle, a regular polygon, etc.).

[0057] In the representative example of the above-described embodiment, the first mark 71, the second mark 72, the third mark 73, and the fourth mark 74 all have the shape of the letter "V," and the direction in which the sharp corners point indicates the direction indicated by each mark. However, directions may be indicated by marks of other shapes. For example, the first mark 71, the second mark 72, the third mark 73, and the fourth mark 74 may all be replaced with arrow shapes. For example, in the first normal display case, the arrows of the first mark and the third mark may both be positioned to point downwards, and in the first abnormal display case, the arrows of the first mark and the third mark may be positioned to point to different sides. Arrows can also be used for the second and fourth marks in the same way. Furthermore, any or all of the first mark 71, the second mark 72, the third mark 73, and the fourth mark 74 may have different shapes. For example, the first mark may be in the shape of the letter "V," and the third mark may be in the shape of an arrow. In this case as well, in the first normal display, the first and third marks should be positioned so that both indicate the lower side, and in the first abnormal display, the first and third marks should be positioned so that they indicate different sides. The same applies to the relationship between the second and fourth marks.

[0058] In the representative example of the above-described embodiment, the mark 70 is shaped like the letter "V", and the direction in which the sharp corners point indicates the direction indicated by the mark. However, the direction may be indicated by a mark with a shape other than this. For example, the mark 70 may be replaced by an arrow shape. For example, in the case of a normal arrangement as shown in Figure 3, the arrow replaced by the mark 70 may be positioned to indicate the front, and in the case of an abnormal arrangement as shown in Figure 20, the arrow replaced by the mark 70 may be positioned to indicate the back.

[0059] In the representative example of the above-described embodiment, the mark 70 has a function of indicating a direction, but the mark 70 may have a function of indicating a position. For example, the mark 70 may be caused to function as "a mark disposed on the front side of the center position in the front-rear direction on the side plate portion 60". In this case, in the regular arrangement as shown in FIG. 3, the mark 70, which is "a mark disposed on the front side of the center position in the front-rear direction on the side plate portion 60", is disposed on the front side of the center position in the front-rear direction on the side plate portion 60, so that it is clearly indicated that the side plate portion 60 is in the regular arrangement. On the other hand, in FIG. 20, the mark 70, which is "a mark disposed on the front side of the center position in the front-rear direction on the side plate portion 60", is disposed on the rear side of the center position in the front-rear direction on the side plate portion 60, so that it is clearly indicated that the arrangement is improper. This example is merely an example. For example, the mark 70 may be represented by the character "front" at a position near the front end of the side plate portion 60, and may function as "a mark disposed on the front side of the center position in the front-rear direction on the side plate portion 60". Alternatively, the mark 70 may be represented by the character "rear" at a position near the rear end of the side plate portion 60, and may function as "a mark disposed on the rear side of the center position in the front-rear direction on the side plate portion 60". Alternatively, the mark 70 may be represented by the character "upper" at a position near the upper end of the side plate portion 60, and may function as "a mark disposed on the upper side of the center position in the up-down direction on the side plate portion 60". Alternatively, the mark 70 may be represented by the character "lower" at a position near the lower end of the side plate portion 60, and may function as "a mark disposed on the lower side of the center position in the up-down direction on the side plate portion 60".

[0060] It should be considered that the embodiment disclosed herein is illustrative in all respects and not restrictive. The scope of the present invention is not limited to the embodiment disclosed herein, and is intended to include all modifications within the scope indicated by the claims or within the scope equivalent to the claims.

Description of Reference Numerals

[0061] 1: Water heater 10: Heat exchanger 20: Case 30: Main body 30A: Inner circumference 32: Upper case section 34: Lower case section 36: Opening 38: External part 39: Inner part 42: Upper plate section 42A: Upper first plate part 42B: Upper second plate part 44: Lower plate part 44A: Lower first plate part 44B: Lower second plate part 44Z: Receiving part 46: Front plate part 46Z: Outlet 48: Rear plate part 48Z:Inlet 49:Drain port 58: 1st hole 59:Second hole 60: Side plate part 60A: External part 61: Plate-like part 62: Standing section 64: Outer edge 64A: Surface part 65: Protruding section 70: Mark 71: Mark 1 72: Mark No. 2 73: Third Mark 74: Mark 4 80: Heat transfer tube 90: Corner 110: 1st water flow section 112: First covering section 112A: Hole 112Z: Outer edge 114: 1st fixed part 114A: 3rd hole 120: 2nd water flow section 122: Second covering section 122A: Hole 122Z: Outer edge 124:Second fixed part 124A: 4th hole 131:Cylinder part 132:Cylinder part 141: Packing 142: Packing G: Central axis K: Central axis L: Central axis

Claims

1. A case comprising a main body portion configured in a cylindrical shape with at least one end in the left-right direction having an opening, and a side plate portion attached to the main body portion in a manner that closes the opening, Multiple heat transfer tubes housed within the aforementioned case, A first water passage is attached to the side plate and is a flow path that leads to either the inlet or outlet side of the plurality of heat transfer tubes, A second water passage is attached to the side plate and is a flow path that leads to the other of either the inlet or outlet side of the plurality of heat transfer tubes, It has, A heat exchanger for a gas appliance, wherein the space inside the case is configured as a space through which exhaust gas passes, The side plate portion is provided with a first hole, which is a hole for fixing either the inlet side or the outlet side of the plurality of heat transfer tubes, and a second hole, which is a hole for fixing the other either the inlet side or the outlet side of the plurality of heat transfer tubes. The first water passage is positioned to cover a plurality of the first holes and includes a first covering portion attached to the outer surface of the side plate portion opposite to the space inside the case, The second water-conducting portion is positioned to cover a plurality of the second holes and includes a second covering portion attached to the outer surface. The side plate portion is provided with a first mark and a second mark. The first covering portion is provided with a third mark. The second covering portion is provided with a fourth mark. When the first covering portion is positioned in the correct orientation relative to the side plate portion, the first mark and the third mark indicate a first normal indication; when it is positioned in the wrong orientation, the first mark and the third mark indicate a first abnormal indication. When the second covering portion is positioned in the correct orientation relative to the side plate portion, the second mark and the fourth mark indicate a second normal indication; when it is positioned in the wrong orientation, the second mark and the fourth mark indicate a second abnormal indication. A heat exchanger for gas appliances.

2. The first mark is a mark indicating direction on the side plate portion, The second mark is a mark indicating direction on the side plate portion, The third mark is a mark indicating direction in the first covering portion, The fourth mark is a mark indicating direction in the second covering portion, When the first covering portion is attached to the side plate portion in the correct orientation, the first mark and the third mark are positioned to point to the same side; when it is attached in the wrong orientation, the first mark and the third mark are positioned to point to different sides. When the second covering portion is attached to the side plate portion in the correct orientation, the second mark and the fourth mark will be positioned to face the same side; when it is attached in the wrong orientation, the second mark and the fourth mark will be positioned to face different sides. A heat exchanger for a gas appliance as described in claim 1.

3. The first mark is positioned on the side plate portion closer to the multiple first holes than the second mark. The second mark is positioned on the side plate portion closer to the plurality of second holes than the first mark. A heat exchanger for a gas appliance according to claim 1 or claim 2.

4. The outer edge of the first covering portion has a shape that is rotationally symmetrical with respect to the central axis in the left-right direction. The outer edge of the second covering portion has a shape that is rotationally symmetrical with respect to the central axis in the left-right direction. A heat exchanger for a gas appliance according to claim 1 or claim 2.

5. The first covering portion and the second covering portion have the same common shape. A heat exchanger for a gas appliance according to claim 1 or claim 2.

6. A method for manufacturing a heat exchanger for a gas appliance, comprising: a case comprising a main body portion configured in a cylindrical shape with at least one end in the left-right direction configured as an opening; a side plate portion attached to the main body portion in a manner that closes the opening; a plurality of heat transfer tubes housed in the case; a first water passage portion attached to the side plate portion and being a passage that leads to either the inlet side or the outlet side of the plurality of heat transfer tubes; and a second water passage portion attached to the side plate portion and being a passage that leads to the other either the inlet side or the outlet side of the plurality of heat transfer tubes, wherein the space within the case is configured as a space through which exhaust gas passes, The side plate portion is provided with a plurality of first holes, which are holes for fixing either the inlet side or the outlet side of the plurality of heat transfer tubes, and a plurality of second holes, which are holes for fixing the other part of either the inlet side or the outlet side of the plurality of heat transfer tubes. The first water-conducting section is configured to include a first covering section which is a covering member, The second water-conducting portion is configured to include a second covering portion that is different from the first covering portion, A first mark and a second mark are provided on the side plate portion. A third mark is provided on the first covering portion. A fourth mark is provided on the second covering portion. On the outer surface of the side plate portion opposite to the space inside the case, the first covering portion is attached at a position that covers the plurality of first holes. The second water passage is attached to the outer surface at a position that covers the plurality of second holes. When the first covering portion is positioned in the correct orientation relative to the side plate portion, the first mark and the third mark indicate a first normal indication; when it is positioned in the wrong orientation, the first mark and the third mark indicate a first abnormal indication. When the second covering portion is positioned in the correct orientation relative to the side plate portion, the second mark and the fourth mark indicate a second normal indication; when it is positioned in the wrong orientation, the second mark and the fourth mark indicate a second abnormal indication. A method for manufacturing heat exchangers for gas appliances.

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