JP7220908B2 - Latent heat recovery heat exchanger for gas appliances - Google Patents

Description

The present invention relates to a latent heat recovery heat exchanger for gas appliances.

Conventionally, as a heat exchanger for gas appliances such as hot water supply equipment, it has a heat transfer tube part inside which water passes, and recovers latent heat by exchanging latent heat contained in exhaust gas (combustion exhaust gas) so as to transfer it to water. type heat exchangers are known. For example, a latent heat recovery type heat exchanger disclosed in Patent Document 1 includes a casing inside which serves as a passage for exhaust gas (combustion exhaust gas), and a heat transfer tube portion (heat absorption tube) accommodated in the casing. . The casing has a box body (case main body) that is open at both left and right ends, and a pair of closing members (side plates) that close the left and right ends of the box body (case main body). Both ends of the heat transfer tube portion (heat absorption tube) are inserted into the insertion holes formed in one of the pair of closing members (side plates). brazed to. The heat transfer tube (heat absorption tube) brazed to the blocking member (side plate) is received from the opening of the case body, and each of the pair of blocking members (side plate) is positioned between both openings of the box (case body). Welded around each perimeter. Thereby, a latent heat recovery type heat exchanger is produced.

JP 2017-26286 A

In the latent heat recovery heat exchanger of Patent Document 1 described above, the closing member (side plate) is fixed to the box (case main body) by welding. If it can be fixed to (the case main body), the assembling work becomes easy.

However, in the latent heat recovery type heat exchanger, when latent heat is recovered, drain adheres to the surface of the heat transfer tube (heat absorption tube). When it drips on the bottom plate of the type heat exchanger, it is discharged from the drain hole formed in the bottom plate. For this reason, when adopting a configuration in which the blocking member (side plate) is fixed to the box (case body) using a connecting member, there is a concern that the drain dripping from the heat transfer tube may contact the connecting member, causing deterioration or corrosion. be done.

SUMMARY OF THE INVENTION The present invention has been made to solve at least one of the above-described problems. It is an object of the present invention to provide a type heat exchanger.

A latent heat recovery type heat exchanger for gas appliances, which is a first example of the present invention,
A box having a main body provided with a first opening at an upper end thereof, and a lid attached to the main body so as to close the first opening, wherein the box contains exhaust gas. a case configured as a passage space;
a heat transfer tube portion including a plurality of heat transfer tubes accommodated in the case;
A latent heat recovery type heat exchanger for a gas appliance having
The main body is
a peripheral wall portion surrounding the passage space;
a bottom wall portion provided on the lower end side of the peripheral wall portion;
has
In the peripheral wall portion, an exhaust gas outlet is provided on one side in the front-rear direction, an inflow port for exhaust gas passing through the passage space is provided on the other side in the front-rear direction, and a second opening is provided on one side in the left-right direction. is provided,
Said case is
a plate-like closing member that closes the second opening;
a connecting member that connects the closing member and the peripheral wall;
has
The closing member includes a first through-hole group including a plurality of first through-holes and a second through-hole group including a plurality of second through-holes. A group of holes are arranged apart in the front-rear direction,
Each of the plurality of heat transfer tubes is attached so that one side in the front-rear direction corresponds to each of the first through holes of the first through-hole group, and the other side in the front-rear direction is attached to each of the second through-hole groups. is attached correspondingly to the second through-hole of and is fixed to the closure member in a configuration in which each bent portion is disposed in proximity to the closure member;
An assembly in which the heat transfer tube portion and the closing member are integrally assembled has a configuration in which a plurality of the heat transfer tubes are inserted into the box from the second opening, and the second opening is connected to the closing member. The closing member is fixed to the peripheral wall portion by the connecting member while being arranged in a configuration closed by
One or more overlapping portions are provided in which the bent portions of the plurality of heat transfer tubes overlap vertically while being close to the closing member,
At least one connecting member is provided in a region on the lower end side of the closing member and between the overlapping portion closest to the first through hole group in the front-rear direction and the first through hole group. Fixed.

A latent heat recovery type heat exchanger for gas appliances, which is a second example of the present invention,
A box having a main body provided with a first opening at an upper end thereof, and a lid attached to the main body so as to close the first opening, wherein the box contains exhaust gas. a case configured as a passage space;
a first heat transfer tube portion including a plurality of first heat transfer tubes accommodated in the case;
a second heat transfer tube portion including a plurality of second heat transfer tubes accommodated in the case;
A latent heat recovery type heat exchanger for a gas appliance having
The main body is
a peripheral wall portion surrounding the passage space;
a bottom wall portion provided on the lower end side of the peripheral wall portion;
has
In the peripheral wall portion, an exhaust gas outlet portion is provided on one side in the front-rear direction, an inflow port portion for exhaust gas passing through the passage space is provided on the other side in the front-rear direction, and a second peripheral wall portion is provided on one side in the left-right direction. An opening is provided, and a third opening is provided on the other side in the left-right direction,
Said case is
a plate-shaped first closing member that closes the second opening;
a plate-shaped second closing member that closes the third opening;
a first connecting member that connects the first closing member and the peripheral wall;
a second connecting member that connects the second closing member and the peripheral wall;
has
The first closing member includes a first through-hole group including a plurality of first through-holes and a second through-hole group including a plurality of second through-holes. two groups of through-holes are spaced apart in the front-rear direction,
The second closing member is provided with a third through-hole group including a plurality of third through-holes and a fourth through-hole group including a plurality of fourth through-holes. 4 through-hole groups are arranged apart in the front-rear direction,
Each of the plurality of first heat transfer tubes is attached on one side in the front-rear direction so as to correspond to each of the first through holes of the first through-hole group, and is attached on the other side in the front-rear direction to the second through-hole group. is attached corresponding to each of the second through-holes, and is fixed to the first closing member in a configuration in which the first bending portion, which is each bending portion, is arranged in proximity to the first closing member,
Each of the plurality of second heat transfer tubes is attached on one side in the front-rear direction so as to correspond to each of the third through holes of the third through-hole group, and is attached on the other side in the front-rear direction to the fourth through-hole group. and fixed to the second closing member in a configuration in which the second bending portion, which is each bending portion, is arranged in proximity to the second closing member,
A first assembly in which the first heat transfer tube portion and the first closing member are integrally assembled inserts a plurality of the first heat transfer tubes into the box from the second opening; The first closing member is fixed to the peripheral wall portion by the first connecting member while being arranged in a configuration in which the second opening is closed by the first closing member,
A second assembled body in which the second heat transfer tube portion and the second closing member are integrally assembled inserts a plurality of the second heat transfer tubes into the box from the third opening; The second closing member is fixed to the peripheral wall portion by the second connecting member while the third opening is closed by the second closing member, and
One or more first overlapping portions are provided in which the first bending portions of the plurality of first heat transfer tubes overlap vertically while being close to the first closing member,
One or more second overlapping portions are provided in which the second bent portions of the plurality of second heat transfer tubes overlap vertically while being close to the second closing member,
At least one The first connecting member is fixed,
At least one The second connecting member is fixed.

According to the latent heat recovery type heat exchanger for gas appliances of the first example, the latent heat contained in the exhaust gas can be heated by transferring it to the water passing through the heat transfer tube portion.
In addition, in this latent heat recovery type heat exchanger, each of the plurality of heat transfer tubes is attached on one side in the front-rear direction so as to correspond to the first through hole of each of the first through hole groups, so that the heat transfer tube adheres to the surface of each heat transfer tube. The drained water tends to drip along the inner surface of the closing member from the vicinity of each first through hole. Furthermore, in the overlapped portion where the bent portions of a plurality of heat transfer tubes overlap vertically while being close to the blocking member, the drain adhered to the surface of the upper heat transfer tube tends to drip down along the lower heat transfer tube. However, in this configuration, at least one connecting member is fixed to a region on the lower end side of the blocking member, which is a region between the first through-hole group and the overlapping portion closest to the first through-hole group in the front-rear direction. It is Therefore, at least the connecting member can fix the lower end side of the closing member while avoiding contact with the drain hanging from the surface of the heat transfer tube. Therefore, according to this latent heat recovery type heat exchanger, it is possible to suppress contact of the drain with the connecting member that connects the closing member to the box.

According to the latent heat recovery type heat exchanger for gas appliances, which is the second example, the latent heat contained in the exhaust gas is heated by transferring it to the water passing through the first heat transfer tube portion and the second heat transfer tube portion. be able to.
Further, in this latent heat recovery type heat exchanger, each of the plurality of first heat transfer tubes is attached so that one side in the front-rear direction corresponds to each of the first through holes of the first through hole group. Drain adhered to the surface of is likely to run down along the inner surface of the first closing member from the vicinity of each first through hole. Furthermore, in the first overlapping portion where the first bent portions of the plurality of first heat transfer tubes overlap vertically while being close to the first closing member, the drain adhering to the surface of the upper first heat transfer tube Easy to drip down along the first heat transfer tube. However, in this configuration, in the area on the lower end side of the first closing member, in the area between the first overlapping portion closest to the first through hole group in the front-rear direction and the first through hole group, at least one A first connecting member is fixed. Therefore, at least the first connecting member can fix the lower end side of the first closing member while avoiding contact with drain hanging from the surface of the first heat transfer tube.
Furthermore, in this latent heat recovery type heat exchanger, each of the plurality of second heat transfer tubes is attached on one side in the front-rear direction so as to correspond to the third through hole of each of the third through hole groups. The drain adhering to the surface of the second closing member tends to drip from the vicinity of each third through-hole along the inner surface of the second closing member. Furthermore, in the second overlapping portion where the second bent portions of the plurality of second heat transfer tubes overlap vertically while being close to the second closing member, the drain adhering to the surface of the upper second heat transfer tube Easy to drip down along the second heat transfer tube. However, in this configuration, in the area on the lower end side of the second closing member, in the area between the second overlapping portion closest to the third through-hole group in the front-rear direction and the third through-hole group, at least one A second connecting member is fixed. Therefore, at least the second connecting member can fix the lower end side of the second closing member while avoiding contact with the drain hanging from the surface of the second heat transfer tube.
Therefore, according to this latent heat recovery type heat exchanger, it is possible to suppress contact of the drain with the first connecting member that connects the first closing member to the box, and to connect the second closing member to the box. It is possible to suppress contact of the drain with the second connecting member that causes the drain to contact.

FIG. 1 is a front view schematically illustrating the internal structure of the water heater of Example 1. FIG. FIG. 2 is an explanatory diagram conceptually illustrating the configuration of the water heater. FIG. 3 is a perspective view schematically illustrating a secondary heat exchanger. FIG. 4 is an exploded perspective view schematically illustrating a secondary heat exchanger. FIG. 5 is a perspective view schematically illustrating the main body. FIG. 6 is an exploded perspective view schematically illustrating one side in the left-right direction of the secondary heat exchanger. FIG. 7 is a plan view schematically illustrating a first heat transfer tube. FIG. 8 is an exploded perspective view schematically illustrating the other side in the left-right direction of the secondary heat exchanger. FIG. 9 is a plan view schematically illustrating a second heat transfer tube. FIG. 10 is a flow chart illustrating the manufacturing process of the secondary heat exchanger. FIG. 11 is an explanatory diagram illustrating a state before attaching the first assembly and the second assembly to the main body. FIG. 12 is a state in which the first assembled body and the second assembled body are attached to the main body, and a cut surface cut along a plane along the vertical direction and the horizontal direction is viewed from one side in the front-rear direction. FIG. 4 is an exemplary cross-sectional view; FIG. 13 illustrates a state in which the first connecting member is fixed to the region between the first overlapping portion closest to the first through-hole group in the front-rear direction and the first through-hole group, viewed from above. It is an explanatory diagram. FIG. 14 illustrates a state in which the second connecting member is fixed to the region between the second overlapping portion closest to the second through-hole group in the front-rear direction and the second through-hole group, viewed from above. It is an explanatory diagram.

<Example 1>
The first embodiment will be described below with reference to FIGS. 1 to 14. FIG.
(Configuration of hot water supply device 1)
The water heater 1 shown in FIGS. 1 and 2 includes a first gas burner 2, a water inlet pipe 4, a hot water outlet pipe 6, a heat exchanger 8, a first connecting pipe 15, etc., and heats tap water supplied from the outside. It has a function to discharge hot water. The first gas burner 2 (hot water supply burner) is a part that burns combustion gas to generate combustion exhaust (exhaust gas). The water inlet pipe 4 is configured as a path into which water flows from the water inlet 16 , and the hot water outlet pipe 6 is configured as a route through which hot water is delivered to the hot water outlet 18 . The heat exchanger 8 is provided with a hot water supply side heat transfer tube portion 11 interposed between the water inlet pipe 4 and the hot water outlet pipe 6, and the water passing through the inside of the hot water supply side heat transfer pipe portion 11 is It is the part that functions to transfer the heat generated by combustion.

The heat exchanger 8 includes a primary heat exchanger 9 and a secondary heat exchanger 10. The primary heat exchanger 9 is arranged upstream of the combustion exhaust path of the first gas burner 2, and the secondary heat exchanger 10 is arranged downstream of the combustion exhaust path. The hot water supply side heat transfer tube portion 11 includes a first heat transfer tube portion 12 and a third heat transfer tube portion 13, the first heat transfer tube portion 12 is provided in the secondary heat exchanger 10, and the third heat transfer tube portion 13 is provided in the primary heat exchanger 9 . A first heat transfer pipe portion 12 of the secondary heat exchanger 10 is connected to the downstream side of the water inlet pipe 4, and a first connecting pipe 15 is connected to the downstream side of the first heat transfer pipe portion 12. . The third heat transfer pipe portion 13 of the primary heat exchanger 9 is connected to the downstream side of the first connecting pipe 15 , and the hot water discharge pipe 6 is connected to the downstream side of the third heat transfer pipe portion 13 .

The heat exchanger 8 functions to recover latent heat by the secondary heat exchanger 10 after the sensible heat of the combustion exhaust is recovered by the primary heat exchanger 9 . The primary heat exchanger 9 transfers the combustion heat contained in the combustion exhaust gas generated by the first gas burner 2 to the water passing through the third heat transfer tube portion 13, and transfers the thermal energy of the sensible heat to the water. to exchange heat. The secondary heat exchanger 10 transfers the combustion heat after the combustion exhaust gas generated by the first gas burner 2 has passed through the primary heat exchanger 9 to the water passing through the first heat transfer tube portion 12, and converts the heat of latent heat. It exchanges heat to transfer energy to water.

The hot water supply apparatus 1 includes a second gas burner 102, an outgoing pipe 104, a return pipe 106, a second connecting pipe 115, and the like, and has a function of reheating a bath using the heat exchanger 8 described above. The second gas burner 102 (bath burner) is a part that burns combustion gas to generate combustion exhaust (exhaust gas). The incoming piping 104 is a path that guides water from the bathtub 20 side to the heat exchanger 8 via the inlet 116 . The return pipe 106 is a path that guides the water from the heat exchanger 8 to the bathtub 20 side via the outlet 118 . The heat exchanger 8 described above is provided with a bath-side heat transfer pipe portion 111 interposed between the forward pipe 104 and the return pipe 106, and the water passing through the bath-side heat transfer pipe portion 111 is heated by the second gas burner 102. functions to transfer heat generated by combustion in

The bath-side heat transfer tube portion 111 includes a second heat transfer tube portion 112 and a fourth heat transfer tube portion 113. The second heat transfer tube portion 112 is provided in the secondary heat exchanger 10, and the fourth heat transfer tube portion 113 is provided in the primary heat exchanger 9 . A second heat transfer pipe portion 112 of the secondary heat exchanger 10 is connected to the downstream side of the outgoing pipe 104, and a second connecting pipe 115 is connected to the downstream side of the second heat transfer pipe portion 112. . The fourth heat transfer pipe portion 113 of the primary heat exchanger 9 is connected to the downstream side of the second connecting pipe 115, and the return pipe 106 is connected to the downstream side of this heat transfer pipe portion.

The primary heat exchanger 9 described above transfers the combustion heat contained in the combustion exhaust generated by the second gas burner 102 to the water passing through the fourth heat transfer tube portion 113, and transfers the thermal energy of sensible heat to the water. heat exchange in the form of In addition, the secondary heat exchanger 10 transfers the combustion heat after the combustion exhaust gas generated by the second gas burner 102 has passed through the primary heat exchanger 9 to the water passing through the second heat transfer tube portion 112, and the latent heat heat exchange so that the heat energy of the water is transferred to the water.

The water heater 1 also includes a drain pipe 22 and a neutralizer 24 . The drain pipe 22 is connected to the drain joint 26 (see FIG. 3) of the secondary heat exchanger 10 on the upstream side and to the neutralizer 24 on the downstream side. Drainage generated by recovery of latent heat in the secondary heat exchanger 10 is discharged to the outside of the secondary heat exchanger 10 through a drain hole 49 (see FIG. 12) and sent to the neutralizer 24 through a drain pipe 22. .

Hot water supply apparatus 1 includes a controller 28 as a control device. The controller 28 is configured, for example, as a known microcomputer or the like, is configured to be able to acquire signals from various sensors provided in the water heater 1, and operates various actuators provided in the water heater 1. It has a controllable configuration. For example, the water heater 1 operates the first gas burner 2 to generate hot water when a water flow sensor (not shown) detects water flow in the water inlet pipe 4 . As another example, hot water supply apparatus 1 operates second gas burner 102 to reheat a bath or the like when a water flow sensor (not shown) detects water flow in incoming pipe 104 .

(Configuration of secondary heat exchanger 10)
Next, the configuration of the secondary heat exchanger 10 will be described with reference to FIGS. 3 to 9. FIG. In this embodiment, the arrangement direction of the first heat transfer tubes 80 (arrangement direction of the heat transfer tubes) is the vertical direction of the secondary heat exchanger 10, and the lateral direction of the water heater 1 is the lateral direction of the secondary heat exchanger 10. , and the direction orthogonal to the up-down direction and the left-right direction of the secondary heat exchanger 10 is defined as the front-rear direction of the secondary heat exchanger 10 . The front side is one side in the front-rear direction, the rear side is the other side in the front-rear direction, the right side is one side in the left-right direction, and the left side is the other side in the left-right direction.

The secondary heat exchanger 10 corresponds to an example of a latent heat recovery type heat exchanger for gas appliances, and has a case 30 and a first heat transfer tube portion 12 as shown in FIG. The case 30 has a box 31 elongated in the left-right direction, and the inside of the box 31 is configured as a passage space PS for the exhaust gas.

The box 31 includes a body portion 32, a lid portion 33, and a first sealing member 34, as shown in FIG. The body portion 32 is formed in a box shape with an open upper side by drawing a metal plate. That is, the main body portion 32 is configured as a drawn body. A first opening 35 is provided at the upper end of the main body 32 . The lid portion 33 is a member attached to the main body portion 32 so as to close the first opening portion 35 . The first seal member 34 is a member that is interposed between the main body portion 32 and the lid portion 33 and suppresses passage of gas between the main body portion 32 and the lid portion 33 .

The body portion 32 has a peripheral wall portion 36 surrounding the passage space PS and a bottom wall portion 37 provided on the lower end side of the peripheral wall portion 36, as shown in FIG.

The peripheral wall portion 36 is provided with an exhaust gas outlet portion 38 on one side in the front-rear direction, an inflow port portion 39 for exhaust gas passing through the passage space PS on the other side in the front-rear direction, and an exhaust gas inlet portion 39 on one side in the left-right direction. Two openings 40 are provided. The peripheral wall portion 36 includes a first wall portion 41 forming one side in the front-rear direction, a second wall portion 42 forming the other side in the front-rear direction, a third wall portion 43 forming one side in the left-right direction, and the other side in the left-right direction. and a fourth wall portion 44 forming a side. The first wall portion 41 is provided with the outlet portion 38 described above, the second wall portion 42 is provided with the inlet portion 39 described above, and the third wall portion 43 is provided with the second opening portion 40 described above. is provided. A plurality of first connected portions 45 are formed around the second opening 40 in the third wall portion 43 . Each of the first connected portions 45 is a portion to which a first connecting member 54, which will be described later, is connected, and has a female screw shape.

The plurality of first connected portions 45 includes first connected portions 45A and 45B provided in the region on the lower end side of the peripheral wall portion 36, and first connected portion 45C provided in the region on the upper end side of the peripheral wall portion 36. and the first connected portions 45D and 45E provided in the region on one side in the front-rear direction of the peripheral wall portion 36 and the first connected portions 45F and 45G provided in the region on the other side in the front-rear direction of the peripheral wall portion 36. have. The first connected portions 45A and 45B are provided apart from each other in the front-rear direction. The first connected portion 45C is provided at a position between the first connected portion 45A and the first connected portion 45B in the front-rear direction. The first connected portions 45D and 45E are provided apart from each other in the vertical direction. The first connected portions 45F and 45G are provided apart from each other in the vertical direction.

The bottom wall portion 37 has an overhang portion 47 and a groove portion 48 . The protruding portion 47 protrudes upward from the groove portion 48 at substantially the center of the bottom wall portion 37 . The groove portion 48 is provided around the projecting portion 47 and constitutes the outer peripheral portion of the bottom wall portion 37 . A drain hole 49 (see FIG. 12) is formed vertically through the bottom wall portion 37 (specifically, the groove portion 48) on one side in the front-rear direction. Then, the drain generated by recovering the latent heat is discharged. The bottom wall portion 37 is disposed inclined downward toward one side in the front-rear direction.

As shown in FIGS. 4 and 6, the case 30 has a first closing member 50, a second sealing member 51, a first header 52, a second header 53, a first connecting member 54, a drain joint 26, and the like.
The first closing member 50 is a member that closes the second opening 40 of the main body 32 and has a plate shape. The first closing member 50 includes a first through-hole group 61 having a plurality of first through-holes 60, a second through-hole group 63 having a plurality of second through-holes 62, a first plate-like portion 64, and a 1 bulging portion 65 and a first insertion hole 66 .

The first group of through holes 61 and the second group of through holes 63 are spaced apart in the front-rear direction. The first through-hole group 61 is arranged on one side in the front-rear direction, and the second through-hole group 63 is arranged on the other side in the front-rear direction. The first through-hole group 61 is arranged such that the positions of the first through-holes 60 are shifted in the vertical direction and the positions of the first through-holes 60 are shifted in the front-rear direction. Similarly to the first through-hole group 61, the second through-hole group 63 has a configuration in which the positions of the second through-holes 62 are shifted in the vertical direction and the positions of the second through-holes 62 are shifted in the front-rear direction. placed.

The first plate-shaped portion 64 is arranged along the vertical direction and the front-rear direction. That is, the first plate-shaped portion 64 is arranged along a plane parallel to the vertical direction and the front-rear direction.

The first bulging portion 65 is provided substantially in the center of the first closing member 50 in the front-rear direction, and has a shape that bulges toward one side in the left-right direction from the first plate-like portion 64 . The first swelling portion 65 has a substantially rectangular shape when viewed from one side in the left-right direction. The first swelling portion 65 has a first recess portion 65A. The first recessed portion 65A is provided at an upper end portion of the first bulging portion 65 substantially in the center in the front-rear direction, and is recessed downward.

The first insertion hole 66 is a hole through which the first connecting member 54 is inserted, and has a shape that penetrates the first closing member 50 (specifically, the first plate-like portion 64) in the left-right direction. Each of the plurality of first insertion holes 66 is provided at a position corresponding to each of the first connected portions 45 . In this embodiment, the plurality of first insertion holes 66 have first insertion holes 66A, 66B, 66C, 66D, 66E, 66F, 66G. , 66F and 66G are provided corresponding to the respective positions of the first connected portions 45A, 45B, 45C, 45D, 45E, 45F and 45G.

The first insertion holes 66</b>A and 66</b>B are arranged below the lower end of the first swelling portion 65 . One end of the first insertion hole 66</b>A is arranged on one side of the first swelling portion 65 in the front-rear direction, and the other end of the first insertion hole 66</b>A is located closer to the first swelling portion 65 . It is arranged on the other side of the one end. One end of the first insertion hole 66</b>B is positioned closer to one side than the other end of the first swelling portion 65 in the front-rear direction, and the other end of the first insertion hole 66</b>B is located closer to the first swelling portion 65 . It is arranged on the other side of the end on the other side. The first insertion hole 66C is provided in a region between the first insertion hole 66A and the first insertion hole 66B in the front-rear direction. 66 C of 1st insertion holes are provided in the recessed part of 65 A of 1st recessed parts, and the edge part of the downward side of 66 C of 1st insertion holes is the upper end of the front-back direction both sides of 65 A of 1st recessed parts in the 1st swelling part 65. It is provided below the part. The first insertion holes 66D and 66E are provided on one side in the front-rear direction of the first through-hole group 61 . The first insertion holes 66</b>F, 66</b>G are provided on the other side in the front-rear direction of the second through-hole group 63 .

The first plate-like portion 64 is provided on both sides of the first swelling portion 65 in at least the front-rear direction. The first through hole group 61 is formed in the first plate-like portion 64 on one side in the front-rear direction relative to the first swelling portion 65 . Each of the first through-holes 60 has a common shape, and is arranged in a configuration in which positions are shifted in the vertical direction and alternately in the front-rear direction. The second through-hole group 63 is formed in the first plate-like portion 64 on the other side in the front-rear direction relative to the first swelling portion 65 . Each of the second through-holes 62 has a common shape, and is arranged such that their positions are shifted in the vertical direction and alternately shifted in the front-rear direction. Each of the second through-holes 62 is arranged in a staggered configuration in the same manner as each of the first through-holes 60 in the vertical direction and the front-rear direction.

The second sealing member 51 has an annular shape and is interposed between the box 31 and the first closing member 50 to suppress passage of gas between the box 31 and the first closing member 50 . be.

The first header 52 connects the upstream side of the first heat transfer tube portion 12 (specifically, the first heat transfer tube 80) and the downstream side of the pipe on the water inlet 16 side (specifically, the water inlet pipe 4). part. That is, the upstream side of the first heat transfer tube portion 12 (specifically, the first heat transfer tube 80) is downstream of the pipe on the water inlet 16 side (specifically, the water inlet pipe 4) via the first header 52. connected to the side. The first header 52 has a first header body 70 , a first header lid 71 and a first joint tube 72 . The first header main body 70 has a container shape that is open on one side, and has a first bottom hole 70A formed in the bottom surface thereof. The first bottom hole 70A is provided corresponding to each position of the first through hole 60 . The first header lid body 71 is a member that closes an opening on one side of the first header body 70 by being attached to the first header body 70, and has a first lid hole 71A. The first cover hole 71A has a larger opening area than the first through hole 60 and is provided on the other side of the first header cover 71 in the vertical direction. The first joint cylinder 72 is attached to the first header lid body 71 so that the inside of the cylinder communicates with the first lid hole 71A, and the pipe on the side of the water inlet 16 (specifically, the water inlet pipe 4). It is a member to which the downstream side is connected. The first header 52 is assembled by attaching the first header lid 71 to the first header main body 70 and attaching the first joint tube 72 to the first header lid 71 .

The second header 53 connects the downstream side of the first heat transfer tube portion 12 (specifically, the first heat transfer tube 80) and the upstream side of the pipe (specifically, the first connecting pipe 15) on the hot water outlet 18 side. This is the connecting part. That is, the downstream side of the first heat transfer pipe portion 12 (specifically, the first heat transfer pipe 80) is connected to the pipe (specifically, the first connecting pipe 15) on the side of the outlet port 18 via the second header 53. connected to the upstream side of The second header 53 has a second header body 73 , a second header lid 74 and a second joint tube 75 . The second header main body 73 has a container shape that is open on one side, and has a second bottom hole 73A formed in the bottom surface thereof. A second bottom hole 73</b>A is provided corresponding to each position of the second through hole 62 . The second header lid body 74 is a member that closes an opening on one side of the second header body 73 by being attached to the second header body 73, and has a second lid hole 74A. The second cover hole 74</b>A has an opening area larger than that of the second through hole 62 and is provided on the upper side of the second header cover 74 . Further, the second cover hole 74A is provided above the first cover hole 71A. The second joint pipe 75 is attached to the second header lid body 74 so that the inside of the pipe communicates with the second lid hole 74A, and is connected to the pipe on the outlet port 18 side (specifically, the first connecting pipe 15). ) is a member to which the upstream side of is connected. The second header 53 is assembled by attaching the second header lid 74 to the second header main body 73 and attaching the second joint tube 75 to the second header lid 74 . The second header main body 73 has the same shape as the first header main body 70 , and the second joint tube 75 has the same shape as the first joint tube 72 .

The first connecting member 54 is a member that connects the first closing member 50 and the peripheral wall portion 36, and is configured as a metal screw, for example. Each of the plurality of first connecting members 54 is inserted through the first insertion hole 66 of the first closing member 50 and connected to the first connected portion 45 . Specifically, the plurality of first connecting members 54 have first connecting members 54A, 54B, 54C, 54D, 54E, 54F, and 54G, and the first connecting members 54A are inserted into the first insertion holes 66A. and connected to the first connected portion 45A, the first connecting member 54B is inserted through the first insertion hole 66B and connected to the first connected portion 45B, and the first connection member 54C is inserted through the first insertion hole 66C. and connected to the first connected portion 45C, the first connecting member 54D is inserted through the first insertion hole 66D and connected to the first connected portion 45D, and the first connection member 54E is inserted through the first insertion hole 66E. and connected to the first connected portion 45E, the first connecting member 54F is inserted through the first insertion hole 66F and connected to the first connected portion 45F, and the first connection member 54F is inserted through the first insertion hole 66F. The first connecting member 54G is inserted through the first insertion hole 66G and connected to the first connecting portion 45G. When the first connecting member 54 is connected to the first connected portion 45 , the first closing member 50 is positioned between the box 31 (specifically, the third wall portion 43 ) and the screw head of the first connecting member 54 . , and the first closing member 50 is connected to the box 31 (specifically, the third wall portion 43).

The drain joint 26 is provided on one side of the case 30 in the front-rear direction and on the lower surface of the case 30 and communicates with the passage space PS formed inside the case 30 .

The first heat transfer tube section 12 includes a plurality of first heat transfer tubes 80 housed inside the case 30 . The first heat transfer tubes 80 meander along a predetermined plane direction. Each of the first heat transfer tubes 80 has a common shape. As shown in FIG. 7, the first heat transfer tube 80 includes a first connection portion 81, a second connection portion 82, a plurality of (six in this embodiment) first linear tube portions 83, and at least one and (five in this embodiment) first bent portions 84 .
The first heat transfer tubes 80 are rotationally asymmetric with respect to the center line in the arrangement direction of the first straight tube portions 83 . That is, when the first heat transfer tube 80 is rotated 180° around the center line in the arrangement direction of the first straight tube portions 83, the form seen from the axial direction differs before and after the rotation.

The first connection portion 81 is a portion connected to an upstream pipe (specifically, the water inlet pipe 4) or a downstream pipe (specifically, the first connecting pipe 15). 80 is provided on one end side. The second connection portion 82 is a portion connected to an upstream pipe (specifically, the water inlet pipe 4) or a downstream pipe (specifically, the first connecting pipe 15). 80 is provided on the other end side. The first connecting portion 81 and the second connecting portion 82 are arranged apart from each other in the arrangement direction of the first straight tubular portion 83 and arranged on the same side in the extending direction of the first straight tubular portion 83. there is

Each of the first straight tubular portions 83 is arranged in parallel with each other. The six first straight pipe portions 83 shown in FIG. 7 are referred to as first straight pipe portions 83A, 83B, 83C, 83D, 83E, and 83F in order from the first connecting portion 81 side. The first linear tubular portion 83 is arranged to extend along the left-right direction. The first straight pipe portion 83A is connected to the first connection portion 81, and the first straight pipe portion 83F is connected to the second connection portion .

The five first bent portions 84 shown in FIG. 7 are referred to as first bent portions 84A, 84B, 84C, 84D, and 84E in order from the first connecting portion 81 side. The first bent portion 84 is a portion that connects the first linear tubular portions 83 to each other. The first bent portion 84A connects the first linear tubular portions 83A and 83B to each other, the first bent portion 84B connects the first linear tubular portions 83B and 83C to each other, and the first bent portion 84C connects the first linear tubular portions 83B and 83C to each other. The first straight tube portions 83C and 83D are connected to each other, the first bending portion 84D connects the first straight tube portions 83D and 83E to each other, and the first bending portion 84E connects the first straight tube portions 83E and 83F. are connected to each other. The lengths of the first bent portions 84B, 84C, 84D, and 84E are the same in the arrangement direction of the first linear tube portions 83. As shown in FIG. The length of the first bent portion 84A is different from the lengths of the other first bent portions 84B, 84C, 84D and 84E in the arrangement direction of the first straight tubular portions 83. As shown in FIG. Specifically, the length of the first bent portion 84A is longer than the lengths of the other first bent portions 84B, 84C, 84D, and 84E in the arrangement direction of the first straight tubular portions 83. As shown in FIG. Of the plurality of first bent portions 84, the odd-numbered first bent portions 84 (specifically, the first bent portions 84A, 84C, and 84E) from the first connecting portion 81 side are the even-numbered first bent portions. It is arranged closer to the first closing member 50 than 84 (specifically, the first bent portions 84B and 84D).

The gap between the first straight tubular portion 83A and the first straight tubular portion 83B is W1, and the gap between the other first straight tubular portions 83 is W2 (specifically, the first straight tubular portion 83B). The gap W2 between the straight tube portion 83B and the first straight tube portion 83C, the gap W2 between the first straight tube portion 83C and the first straight tube portion 83D, the first straight tube portion 83C and the first straight tube portion 83D The gap W2 between the tube portion 83D and the first straight tube portion 83E is longer than the gap W2 between the first straight tube portion 83E and the first straight tube portion 83F.

In addition, as shown in FIG. 5 , the other side of the peripheral wall portion 36 in the left-right direction (specifically, the fourth wall portion 44 ) is provided with a third wall extending through the peripheral wall portion 36 (specifically, the fourth wall portion 44 ). An opening 140 is provided. A plurality of second connected portions 145 are formed around the third opening 140 in the fourth wall portion 44 . Each of the second connected portions 145 is a portion to which a second connecting member 154, which will be described later, is connected, and has a female screw shape.
The plurality of second connected portions 145 includes second connected portions 145A and 145B provided in the region on the lower end side of the peripheral wall portion 36, and a second connected portion 145C provided in the region on the upper end side of the peripheral wall portion 36. and the second connected portions 145D and 145E provided in the region on one side in the front-rear direction of the peripheral wall portion 36, and the second connected portions 145F and 145G provided in the region on the other side in the front-rear direction of the peripheral wall portion 36. have. The second connected portions 145A and 145B are provided apart from each other in the front-rear direction. The second connected portion 145C is provided at a position between the second connected portion 145A and the second connected portion 145B in the front-rear direction. The second connected portions 145D and 145E are provided apart from each other in the vertical direction. The second connected portions 145F and 145G are provided apart from each other in the vertical direction.

4 and 8, the case 30 has a second closing member 150, a third sealing member 151, a third header 152, a fourth header 153, a second connecting member 154, a partition plate 55, and the like. . The secondary heat exchanger 10 includes a second heat transfer tube portion 112 .

The second closing member 150 is a member that closes the third opening 140 of the body portion 32 and has a plate shape. The second closing member 150 includes a third through-hole group 161 having a plurality of third through-holes 160, a fourth through-hole group 163 having a plurality of fourth through-holes 162, a second plate-like portion 164, and a It has two swelling portions 165 and a second insertion hole 166 . The second closing member 150 has the same shape as the first closing member 50 .

The third through-hole group 161 and the fourth through-hole group 163 are spaced apart in the front-rear direction. The third through-hole group 161 is arranged on one side in the front-rear direction, and the fourth through-hole group 163 is arranged on the other side in the front-rear direction. The third through-hole group 161 is arranged such that the positions of the third through-holes 160 are shifted in the vertical direction and the positions of the third through-holes 160 are shifted in the front-rear direction. Similarly to the third through-hole group 161, the fourth through-hole group 163 is configured such that the positions of the fourth through-holes 162 are shifted in the vertical direction and the positions of the fourth through-holes 162 are shifted in the front-rear direction. placed.

The second plate-shaped portion 164 is arranged along the vertical direction and the front-rear direction. That is, the second plate-shaped portion 164 is arranged along a plane parallel to the vertical direction and the front-rear direction.

The second bulging portion 165 is provided substantially in the center of the second closing member 150 in the front-rear direction, and has a shape that bulges further toward the other side in the left-right direction than the second plate-shaped portion 164 . The second swelling portion 165 has a substantially rectangular shape when viewed from one side in the left-right direction. The second swelling portion 165 has a second recessed portion 165A. The second recessed portion 165A is provided at an upper end portion of the second bulging portion 165 in the approximate center in the front-rear direction, and is recessed downward.

The second insertion hole 166 is a hole through which the second connecting member 154 is inserted, and has a shape that penetrates the second closing member 150 (specifically, the second plate-like portion 164) in the left-right direction. Each of the plurality of second insertion holes 166 is provided at a position corresponding to each of the second connected portions 145 . In this embodiment, the plurality of second insertion holes 166 have second insertion holes 166A, 166B, 166C, 166D, 166E, 166F and 166G. , 166F and 166G are provided corresponding to the respective positions of the second connected portions 145A, 145B, 145C, 145D, 145E, 145F and 145G.

The second insertion holes 166A and 166B are arranged below the lower end of the second swelling portion 165 . The second insertion hole 166</b>A has one end located on one side of the second bulging portion 165 in the front-rear direction, and the other end of the second bulging portion 165 . It is arranged on the other side of the one end. One end of the second insertion hole 166B is arranged on one side of the second bulge portion 165 relative to the other end of the second bulge portion 165 in the front-rear direction. It is arranged on the other side of the end on the other side. The second insertion hole 166C is provided in a region between the second insertion hole 166A and the second insertion hole 166B in the front-rear direction. 166 C of 2nd insertion holes are provided in the recessed part of 165 A of 2nd recessed parts, and the edge part of the downward side of 166 C of 2nd insertion holes is the upper end of the front-back direction both sides of the 2nd recessed part 165A in the 2nd swelling part 165 It is provided below the part. The second insertion holes 166D and 166E are provided on one side in the front-rear direction of the third through-hole group 161. As shown in FIG. The second insertion holes 166</b>F, 166</b>G are provided on the other side in the front-rear direction of the fourth through-hole group 163 .

The second plate-shaped portion 164 is provided on both sides of the second swelling portion 165 at least in the front-rear direction. The third through-hole group 161 is formed in the second plate-like portion 164 on one side in the front-rear direction relative to the second swelling portion 165 . Each of the third through-holes 160 has a common shape, and is arranged such that their positions are shifted in the vertical direction and alternately shifted in the front-rear direction. The fourth through-hole group 163 is formed in the second plate-like portion 164 on the other side in the front-rear direction relative to the second swelling portion 165 . Each of the fourth through-holes 162 has a common shape, and is arranged such that their positions are shifted in the vertical direction and alternately shifted in the front-rear direction. Each of the fourth through-holes 162 is arranged in a staggered configuration in the same manner as each of the third through-holes 160 in the vertical direction and the front-rear direction.

The third sealing member 151 has an annular shape, is interposed between the box 31 and the second closing member 150, and is a member that suppresses passage of gas between the box 31 and the second closing member 150. be.

The third header 152 is a portion that connects the upstream side of the second heat transfer tube portion 112 and the downstream side of the inlet 116 side pipe (specifically, the outgoing pipe 104). That is, the upstream side of the second heat transfer tube portion 112 is connected to the downstream side of the inlet 116 side pipe (specifically, the outgoing pipe 104 ) via the third header 152 . The third header 152 has a third header body 170 , a third header lid body 171 and a third joint cylinder 172 . The third header main body 170 has a container shape that is open on one side, and has a third bottom hole 170A formed in the bottom surface thereof. A third bottom hole 170A is provided corresponding to each position of the third through hole 160 . The third header lid body 171 is a member that closes an opening on one side of the third header body 170 by being attached to the third header body 170, and has a third lid hole 171A. The third cover hole 171</b>A has an opening area larger than that of the third through hole 160 and is provided on the lower side of the third header cover 171 . The third joint cylinder 172 is attached to the third header lid body 171 so that the inside of the cylinder thereof communicates with the third lid hole 171A, and the third joint cylinder 172 is connected downstream of the pipe on the side of the inlet 116 (specifically, the outgoing pipe 104). It is the member to which the side is connected. The third header 152 is assembled by attaching the third header lid 171 to the third header main body 170 and attaching the third joint tube 172 to the third header lid 171 . The third header 152 has the same shape as the first header 52 .

The fourth header 153 is a portion that connects the downstream side of the second heat transfer tube portion 112 and the upstream side of the pipe on the outlet 118 side (specifically, the second connecting pipe 115). That is, the downstream side of the second heat transfer tube portion 112 is connected to the upstream side of the pipe on the outlet 118 side (specifically, the second connecting pipe 115 ) via the fourth header 153 . The fourth header 153 has a fourth header main body 173 , a fourth header lid body 174 and a fourth joint tube 175 . The fourth header main body 173 has a container shape that is open on one side, and has a fourth bottom hole 173A formed in the bottom surface thereof. The fourth bottom hole 173A is provided corresponding to each position of the fourth through hole 162 . The fourth header lid body 174 is a member that closes an opening on one side of the fourth header body 173 by being attached to the fourth header body 173, and has a fourth lid hole 174A. The fourth cover hole 174</b>A has an opening area larger than that of the fourth through hole 162 and is provided on the upper side of the fourth header cover 174 . Further, the fourth cover hole 174A is provided above the third cover hole 171A. The fourth joint pipe 175 is attached to the fourth header lid body 174 so that the inside of the pipe thereof communicates with the fourth lid hole 174A, and is connected to a pipe on the outlet 118 side (specifically, the second connecting pipe 115). is a member to which the upstream side of is connected. The fourth header 153 is assembled by attaching the fourth header lid 174 to the fourth header main body 173 and attaching the fourth joint tube 175 to the fourth header lid 174 . The fourth header body 173 has a shape common to that of the third header body 170 , and the fourth joint cylinder 175 has a shape common to that of the third joint cylinder 172 . The fourth header 153 has the same shape as the second header 53 .

The second connecting member 154 is a member that connects the second closing member 150 and the peripheral wall portion 36, and is configured as a metal screw, for example. Each of the second connecting members 154 is inserted through the second insertion hole 166 of the second closing member 150 and connected to the second connected portion 145 . Specifically, the plurality of second connecting members 154 have second connecting members 154A, 154B, 154C, 154D, 154E, 154F, and 154G, and the second connecting members 154A are inserted into the second insertion holes 166A. The second connecting member 154B is inserted through the second insertion hole 166B and is connected to the second connection receiving portion 145B, and the second connection member 154C is inserted through the second insertion hole 166C. The second connecting member 154D is inserted through the second insertion hole 166D and is connected to the second connection receiving portion 145D, and the second connection member 154E is inserted through the second insertion hole 166E. The second connecting member 154F is inserted through the second insertion hole 166F and connected to the second connection receiving portion 145F, and the second connection member 154F is inserted through the second insertion hole 166F. The second connecting member 154G is inserted through the second insertion hole 166G and connected to the second connecting portion 145G. When the second connecting member 154 is connected to the second connected portion 145 , the second closing member 150 is positioned between the box 31 (specifically, the fourth wall portion 44 ) and the screw head of the second connecting member 154 . , and the second closing member 150 is connected to the box 31 (specifically, the fourth wall 44).

The second heat transfer tube section 112 includes a plurality of second heat transfer tubes 180 housed inside the case 30 . The second heat transfer tubes 180 meander along a predetermined plane direction. Each of the second heat transfer tubes 180 has a common shape. As shown in FIG. 9, the second heat transfer tube 180 includes a third connecting portion 181, a fourth connecting portion 182, a plurality of (six in this embodiment) second straight pipe portions 183, and at least one and (five in this embodiment) second bent portions 184 .

The second heat transfer tube 180 has a non-rotationally symmetrical shape about the center line in the arrangement direction of the second straight tube portions 183 . That is, when the second heat transfer tubes 180 are rotated 180° about the center line in the arrangement direction of the second straight tube portions 183, the shape of the second heat transfer tubes 180 seen from the axial direction differs before and after the rotation. The first heat transfer tube 80 and the second heat transfer tube 180 differ only in the length in the extension direction of the first straight tube portion 83 and the length in the extension direction of the second straight tube portion 183, and other configurations (for example, The diameter of the tube, the length of the linear tube in the arrangement direction, the number of bends, etc.) are the same.

The third connection portion 181 is a portion connected to an upstream pipe (specifically, the outgoing pipe 104) or a downstream pipe (specifically, the second connecting pipe 115), and is a part connected to the second heat transfer pipe 180 is provided on one end side. The fourth connection portion 182 is a portion connected to an upstream pipe (specifically, the outgoing pipe 104) or a downstream pipe (specifically, the second connecting pipe 115), and is a part connected to the second heat transfer pipe 180 is provided on the other end side. The third connecting portion 181 and the fourth connecting portion 182 are arranged apart from each other in the arrangement direction of the second straight tubular portion 183 and arranged on the same side in the extending direction of the second straight tubular portion 183. there is

Each of the second straight tubular portions 183 is arranged in parallel with each other. The six second straight pipe portions 183 shown in FIG. 9 are referred to as second straight pipe portions 183A, 183B, 183C, 183D, 183E, and 183F in order from the third connecting portion 181 side. The second straight tubular portion 183 is arranged to extend in the left-right direction. The second straight pipe portion 183A is connected to the third connection portion 181, and the second straight pipe portion 183F is connected to the fourth connection portion 182. As shown in FIG. The length of the second straight tubular portion 183 is shorter than the length of the first straight tubular portion 83 . That is, the second heat transfer tube 180 has a shorter overall length than the first heat transfer tube 80 .

The five second bent portions 184 shown in FIG. 9 are referred to as second bent portions 184A, 184B, 184C, 184D, and 184E in order from the third connecting portion 181 side. The second bent portion 184 is a portion that connects the second linear tubular portions 183 to each other. The second bent portion 184A connects the second linear tubular portions 183A and 183B to each other, the second bent portion 184B connects the second linear tubular portions 183B and 183C to each other, and the second bent portion 184C connects the second linear tubular portions 183B and 183C to each other. The two straight tubular portions 183C and 183D are connected to each other, the second bent portion 184D connects the second straight tubular portions 183D and 183E to each other, and the second bent portion 184E connects the second straight tubular portions 183E and 183F. are connected to each other. The lengths of the second bent portions 184B, 184C, 184D, and 184E are the same in the arrangement direction of the second straight tubular portions 183. As shown in FIG. The length of the second bent portion 184A is different from the lengths of the other second bent portions 184B, 184C, 184D, and 184E in the arrangement direction of the second linear tube portions 183. As shown in FIG. Specifically, the length of the second bent portion 184A is longer than the lengths of the other second bent portions 184B, 184C, 184D, and 184E in the arrangement direction of the second linear tube portions 183. As shown in FIG. Of the plurality of second bent portions 184, odd-numbered second bent portions 184 (specifically, second bent portions 184A, 184C, and 184E) from the third connecting portion 181 side are even-numbered second bent portions. 184 (specifically, the second bent portions 184B and 184D) are arranged closer to the second closing member 150 side.

The gap between the second straight tube portions 183A and 183B is W3, and the gap between the other second straight tube portions 183 is W4 (specifically, the second straight tube portion 183). The gap W4 between the straight tube portion 183B and the second straight tube portion 183C, the gap W4 between the second straight tube portion 183C and the second straight tube portion 183D, the second straight tube portion 183C and the second straight tube portion 183D It is longer than the gap W4 between the tube portion 183D and the second straight tube portion 183E and the gap W4) between the second straight tube portion 183E and the second straight tube portion 183F.

The partition plate 55 is a member that partitions the inside of the box 31 . The outlet portion 38 described above functions as a first exhaust area 38A and a second exhaust area 38B. The first discharge area 38A and the second discharge area 38B are provided side by side in the third direction. The second discharge area 38B is provided on the other side in the third direction from the first discharge area 38A. The inlet portion 39 described above functions as a first inlet 39A and a second inlet 39B for the exhaust gas. The first inlet 39A and the second inlet 39B are provided side by side in the third direction. The second inlet 39B is provided on the other side in the third direction from the first inlet 39A. The partition plate 55 includes a first passage space PS1 defined between the first inlet 39A and the outlet portion 38 (first discharge area 38A), a second inlet 39B and the outlet portion 38 (second discharge area 38A). 38B).

The partition plate 55 has a partition portion 56 , a lower surface portion 57 and an upper surface portion 58 . The partition portion 56 is a portion that partitions the first passage space PS1 and the second passage space PS2. The lower surface portion 57 is a portion that is connected to the lower end portion of the partition portion 56 and extends in a direction intersecting (for example, perpendicular to) the partition portion 56 . The upper surface portion 58 is a portion that is connected to the upper end portion of the partition portion 56 and extends in a direction intersecting (for example, perpendicular to) the partition portion 56 . The partition plate 55 is arranged with the lower surface portion 57 placed on the upper surface of the bottom wall portion 37 .

(Manufacturing method of secondary heat exchanger 10)
Next, a method for manufacturing the secondary heat exchanger 10 will be described with reference to FIGS. 10, 11 and 12. FIG. The method for manufacturing the secondary heat exchanger 10 includes, as shown in the flowchart of FIG. process (step S14), fifth forming process (step S15), mounting process (step S16), first fixing process (step S17), second fixing process (step S18), third fixing process (step S19), 4 fixing step (step S20). It should be noted that the order in which each step is performed does not matter as long as there is no explicit limitation.

In the first forming step, the body portion 32 is formed by drawing a metal plate.

In the second forming step, in the peripheral wall portion 36, the exhaust port portion 38 that functions as the first exhaust area 38A and the second exhaust area 38B is formed on one side in the second direction, and the exhaust port portion 38 is formed on the other side in the second direction. An inflow port portion 39 functioning as a first inflow port 39A and a second inflow port 39B for exhaust gas is formed, a second opening portion 40 is formed on one side in the third direction, and a third opening portion 40 is formed on the other side in the third direction. An opening 140 is formed, and the first inlet 39A and the second inlet 39B are arranged side by side in the third direction. The outlet portion 38, the inlet portion 39, the second opening portion 40, and the third opening portion 140 are formed by, for example, punching or cutting. In this embodiment, the first ejection area 38A and the second ejection area 38B are formed integrally, but they may be formed separately. Also, in this embodiment, the first inlet 39A and the second inlet 39B are formed separately, but they may be formed as one inlet.

In the third forming step, the plate-like first closing member 50 is formed by processing a metal plate, for example. A first through-hole group 61 having a plurality of first through-holes 60 and a second through-hole group 63 having a plurality of second through-holes 62 are formed in the first closing member 50 . The first through-hole group 61 and the second through-hole group 63 are spaced apart in the front-rear direction. A first insertion hole 66 is formed in the first closing member 50 . The first through-hole group 61, the second through-hole group 63, and the first insertion hole 66 are formed by, for example, punching or cutting. A first swelling portion 65 is formed in the first closing member 50 . The first swelling portion 65 is formed by drawing, for example.

In the fourth forming step, the plate-like second closing member 150 is formed by processing a metal plate, for example. A third through-hole group 161 having a plurality of third through-holes 160 and a fourth through-hole group 163 having a plurality of fourth through-holes 162 are formed in the second closing member 150 . The third through-hole group 161 and the fourth through-hole group 163 are spaced apart in the front-rear direction. A second insertion hole 166 is formed in the second closing member 150 . The third through-hole group 161, the fourth through-hole group 163, and the second through-hole 166 are formed by punching or cutting, for example. A second swelling portion 165 is formed in the second closing member 150 . The second swelling portion 165 is formed by drawing, for example.

In the fifth forming step, the partition plate 55 that partitions the inside of the box 31 is formed by processing a metal plate, for example. The lower surface portion 57 and the upper surface portion 58 of the partition plate 55 are formed by bending, for example.
In the mounting step, the partition plate 55 is mounted inside the case 30 so as to partition the first passage space PS1 and the second passage space PS2. The partition plate 55 is attached inside the case 30 by placing the lower surface portion 57 on the upper surface of the bottom wall portion 37 .

In the first fixing step, as shown in FIG. 11 , in the plurality of first heat transfer tubes 80, one side in the front-rear direction is associated with each first through hole 60 of the first through hole group 61, and attached. The other side in the front-rear direction of the second through-hole group 63 is associated with each second through-hole 62 , and each first bent portion 84 is arranged in proximity to the first closing member 50 . is fixed to the first closing member 50 . In this embodiment, the end of each of the first heat transfer tubes 80 on one side in the front-rear direction is inserted into the first through-hole 60 of each of the first through-hole groups 61, and the other end in the front-rear direction of each of the first heat transfer tubes 80 is inserted. Each of the first heat transfer tubes 80 is fixed to the first closing member 50 by, for example, welding or brazing, with the side end portion inserted into each of the second through holes 62 of the second through hole group 63 . Thereby, the first assembled body 90 in which the first heat transfer tube portion 12 and the first closing member 50 are integrally assembled is manufactured.

In addition, the plurality of first heat transfer tubes 80 are arranged in a first posture in which the first connection portion 81 is arranged on one side in the front-rear direction and the second connection portion 82 is arranged on the other side in the front-rear direction, or the second connection portion 82 is arranged on one side in the front-rear direction and the first connecting portion 81 is arranged on the other side in the front-rear direction. The second posture can also be regarded as a posture in which the posture of the first connection portion 81 in the first posture is reversed. In the first heat transfer tube 80A in the first posture, one end portion (specifically, the first connection portion 81) of the first heat transfer tube 80A in the front-rear direction is located at one end in the front-rear direction among the plurality of first through-holes 60 that are provided so as to be shifted in the front-rear direction. One of the plurality of second through holes 62 in which the end (specifically, the second connection portion 82) on the other side in the front-rear direction is staggered in the front-rear direction. is inserted through the second through hole 62 on the side. That is, the first heat transfer tube 80A in the first posture is arranged at a position shifted to one side in the front-rear direction with respect to the first heat transfer tube 80B in the second posture. The plurality of first heat transfer tubes 80 are fixed to the first closing member 50 such that the first heat transfer tubes 80A in the first posture and the first heat transfer tubes 80B in the second posture are alternately arranged along the vertical direction. be. Thereby, the plurality of first heat transfer tubes 80A are arranged along the vertical direction of the water heater 1 .

In addition, the first header 52 has its own first bottom hole 70A inserted into the end portion of the first heat transfer tube 80 inserted through each of the first through hole groups 61, and the first heat transfer tube is welded or brazed. 80 (see FIGS. 3 and 12). The second header 53 has its own second bottom hole 73A inserted into the end portion of the first heat transfer tube 80 inserted through each of the second through hole groups 63, and is attached to the first heat transfer tube 80 by welding or brazing. It is fixed (see FIGS. 3 and 12).

In the second fixing step, as shown in FIG. 11 , each of the plurality of second heat transfer tubes 180 is attached so that one side in the front-rear direction is associated with each third through hole 160 of the third through hole group 161, and each The other side in the front-rear direction is associated with each fourth through hole 162 of the fourth through hole group 163 and attached, and each second bent portion 184 is arranged in proximity to the second closing member 150. is fixed to the second closing member 150 . In this embodiment, the end of each of the second heat transfer tubes 180 on one side in the front-rear direction is inserted into the third through-hole 160 of each of the third through-hole groups 161, and the other end in the front-rear direction of each of the second heat transfer tubes 180 is inserted. Each of the second heat transfer tubes 180 is fixed to the second closing member 150 by, for example, welding or brazing, with the side end portion being inserted into each of the fourth through holes 162 of the fourth through hole group 163 . As a result, a second assembled body 190 in which the second heat transfer tube portion 112 and the second closing member 150 are integrally assembled is manufactured.

Further, the plurality of second heat transfer tubes 180 are arranged in a third posture in which the third connection portion 181 is arranged on one side in the front-rear direction and the fourth connection portion 182 is arranged on the other side in the front-rear direction, or the fourth connection portion 182 is arranged on one side in the front-rear direction and the third connecting portion 181 is arranged on the other side in the front-rear direction. The fourth posture can also be regarded as a posture in which the posture of the third connecting portion 181 in the third posture is reversed. In the second heat transfer tube 180A in the third posture, one end portion (specifically, the third connecting portion 181) in the front-rear direction is located at one end in the front-rear direction among the plurality of third through-holes 160 that are provided so as to be shifted in the front-rear direction. one of the plurality of fourth through-holes 162 in which the end (specifically, the fourth connecting portion 182) on the other side in the front-rear direction is staggered in the front-rear direction. It is inserted through the fourth through hole 162 on the side. That is, the second heat transfer tube 180A in the third posture is arranged at a position shifted to one side in the front-rear direction with respect to the second heat transfer tube 180B in the fourth posture. The plurality of second heat transfer tubes 180 are fixed to the second closing member 150 such that the second heat transfer tubes 180A in the third posture and the second heat transfer tubes 180B in the fourth posture are alternately arranged along the vertical direction. be. Thereby, the plurality of second heat transfer tubes 180A are arranged along the vertical direction of the water heater 1 .

In addition, the third header 152 inserts its own third bottom hole 170A into the end portion of the second heat transfer tube 180 inserted through each of the third through hole groups 161, and welds or brazes the second heat transfer tube. Fixed at 180. The fourth header 153 is attached to the second heat transfer tubes 180 by welding or brazing by inserting its own fourth bottom holes 173A into the ends of the second heat transfer tubes 180 that are inserted through the fourth through hole groups 163 respectively. Fixed.

In the third fixing step, as shown in FIG. 12 , a first assembled body 90 in which the first heat transfer tube portion 12 and the first closing member 50 are integrally assembled is moved from the second opening 40 to the box 31 . The first closing member 50 is connected to the peripheral wall portion 36 by the first connecting member 54 while being arranged in a configuration in which a plurality of the first heat transfer tubes 80 are inserted inside and a configuration in which the second opening 40 is closed by the first closing member 50 Fixed. Specifically, the first heat transfer tube portion 12 is inserted into the box 31 from the second opening 40, the second opening 40 is closed by the first closing member 50, and the first insertion of the first closing member 50 is performed. The first connecting member 54 inserted through the hole 66 is connected to the first connected portion 45 . At this time, the first end portion 92 of the first heat transfer tube portion 12 opposite to the first closing member 50 side is brought close to the partition portion 56 of the partition plate 55 in the first passage space PS1. In addition, each of the first heat transfer tubes 80 is arranged with one side in the front-rear direction inclined downward.

In the fourth fixing step, as shown in FIG. 12 , the second assembly 190 in which the second heat transfer tube portion 112 and the second closing member 150 are integrally assembled is removed from the third opening 140 to the box 31 . The second closing member 150 is connected to the peripheral wall portion 36 by the second connecting member 154 while being arranged in a configuration in which a plurality of second heat transfer tubes 180 are inserted inside and a configuration in which the third opening 140 is closed by the second closing member 150 Fixed. Specifically, the second heat transfer tube portion 112 is inserted into the box 31 from the third opening 140, the third opening 140 is closed by the second closing member 150, and the second closing member 150 is inserted through the second opening. The second connecting member 154 inserted through the hole 166 is connected to the second connected portion 145 . Thereby, the second assembly 190 is attached to the box 31 . At this time, the second end portion 192 of the second heat transfer tube portion 112 opposite to the second closing member 150 side is brought close to the partition portion 56 of the partition plate 55 in the second passage space PS2. In addition, each of the second heat transfer tubes 180 is arranged with one side in the front-rear direction inclined downward.

A step of closing the first opening 35 of the box 31 to which the first assembly 90 and the second assembly 190 are attached with the lid 33 is performed. The secondary heat exchanger 10 is completed by performing these processes.

(Positional relationship between first connecting member 54 and first overlapping portion 91)
Next, the positional relationship between the first connecting member 54 and the first overlapping portion 91 will be described with reference to FIGS. 6 and 13. FIG.
FIG. 13 illustrates the first closing member 50, the first connecting members 54A, 54B, 54C, 54D, and 54F, and the first heat transfer tube portion 12 when the secondary heat exchanger 10 is completed. As shown in FIG. 13 , the first bent portion 84 on one side in the left-right direction among the plurality of first bent portions 84 is arranged close to the first closing member 50 . A plurality (two in the present embodiment) of the first bent portions 84 arranged close to the first closing member 50 are provided.

The secondary heat exchanger 10 has one or more first overlapping portions 91 in which the first bent portions 84 of the plurality of first heat transfer tubes 80 are arranged in close proximity to the first closing member 50 and vertically overlapped (this embodiment Two in the example) are provided. In the example shown in FIG. 13, the first bent portion 84B of the first heat transfer tube 80A in the first posture and the first bent portion 84D of the first heat transfer tube 80B in the second posture overlap vertically. 91 A of 1st overlap parts arrange|positioned are provided. Furthermore, in the example shown in FIG. 13, the first bent portion 84D of the first heat transfer tube 80A in the first posture and the first bent portion 84B of the first heat transfer tube 80B in the second posture are arranged to overlap vertically. A first overlapping portion 91B is provided. The first overlapping portion 91 is close to the first swelling portion 65 of the first closing member 50 . More specifically, the first overlapping portion 91 is recessed into the first swelling portion 65 .

At least one (In this embodiment, one) first connecting members 54 are fixed. In the example shown in FIG. 13, the first connecting member 54A (more specifically, the male threaded portion of the first connecting member 54A) is the first overlapping portion 91A closest to the first through hole group 61 in the front-rear direction, and the first overlapping portion 91A. It is fixed to the first region AR1 between the through-hole group 61 .

At least one (In this embodiment, one) first connecting members 54 are fixed. In the example shown in FIG. 13 , the first connecting member 54B (more specifically, the male threaded portion of the first connecting member 54B) is the first overlapping portion 91B closest to the second through hole group 63 in the front-rear direction, and the second overlapping portion 91B. It is fixed to the second region AR2 between the through-hole group 63 .

A region on the upper end side of the first closing member 50 and between the first overlapping portion 91 closest to the first through-hole group 61 in the front-rear direction and the first overlapping portion 91 closest to the second through-hole group 63 At least one (in the present embodiment, one) first connecting member 54 is fixed in the area of . In the example shown in FIG. 13, the first connecting member 54C (more specifically, the male threaded portion of the first connecting member 54C) is positioned between the first overlapping portion 91A closest to the first through hole group 61 in the front-rear direction and the second overlapping portion 91A. It is fixed to the third region AR3 between the through hole group 63 and the first overlapping portion 91B closest to it.

(Positional relationship between second connecting member 154 and second overlapping portion 191)
Next, the positional relationship between the second connecting member 154 and the second overlapping portion 191 will be described with reference to FIGS. 8 and 14. FIG.
FIG. 14 illustrates the second closing member 150, the second connecting members 154A, 154B, 154C, 154D, and 154F, and the second heat transfer tube portion 112 in a state where the secondary heat exchanger 10 is completed. As shown in FIG. 14 , the second bent portion 184 on one side in the left-right direction among the plurality of second bent portions 184 is arranged close to the second closing member 150 . A plurality (two in this embodiment) of the second bent portions 184 arranged close to the second closing member 150 are provided.

In the secondary heat exchanger 10, there are one or more second overlapping portions 191 in which the second bent portions 184 of the plurality of second heat transfer tubes 180 overlap vertically while being close to the second closing member 150 (this embodiment Two in the example) are provided. In the example shown in FIG. 14, the second bent portion 184B of the second heat transfer tube 180A in the third posture and the second bent portion 184D of the second heat transfer tube 180B in the fourth posture overlap vertically. A second overlapping portion 191A is provided. Furthermore, in the example shown in FIG. 14, the second bent portion 184D of the second heat transfer tube 180A in the third posture and the second bent portion 184B of the second heat transfer tube 180B in the fourth posture are arranged to overlap vertically. A second overlapping portion 191B is provided. The second overlapping portion 191 is close to the second swelling portion 165 of the second closing member 150 . More specifically, the second overlapping portion 191 is recessed into the second swelling portion 165 .

At least one A second connecting member 154 (one in this embodiment) is fixed. In the example shown in FIG. 14, the second connecting member 154A (more specifically, the male threaded portion of the second connecting member 154A) is the second overlapping portion 191A closest to the third through-hole group 161 in the front-rear direction, and the third overlapping portion 191A. It is fixed to the fourth region AR4 between the through-hole group 161. FIG.
At least one A second connecting member 154 (one in this embodiment) is fixed. In the example shown in FIG. 14 , the second connecting member 154B (more specifically, the male threaded portion of the second connecting member 154B) is positioned between the second overlapping portion 191B closest to the fourth through-hole group 163 in the front-rear direction and the fourth overlapping portion 191B. It is fixed to the fifth region AR5 between the group of through holes 163 .
A region on the upper end side of the second closing member 150 and between the second overlapping portion 191 closest to the third through-hole group 161 in the front-rear direction and the second overlapping portion 191 closest to the fourth through-hole group 163 At least one (in this embodiment, one) second connecting member 154 is fixed in the area of . In the example shown in FIG. 14, the second connecting member 154C (more specifically, the male threaded portion of the second connecting member 154C) is positioned between the second overlapping portion 191A closest to the third through-hole group 161 in the front-rear direction and the fourth overlapping portion 191A. It is fixed to the sixth region AR6 between the through-hole group 163 and the second overlapping portion 191B closest to it.

(effect)
According to the secondary heat exchanger 10 of the first embodiment, the latent heat contained in the exhaust gas can be heated by transferring it to the water passing through the first heat transfer tube portion 12 and the second heat transfer tube portion 112 . .
Further, in the secondary heat exchanger 10, each of the plurality of first heat transfer tubes 80 is attached on one side in the front-rear direction so as to correspond to each of the first through holes 60 of the first through hole group 61. Drain adhered to the surface of the first heat transfer tube 80 tends to drip along the inner surface of the first closing member 50 from the vicinity of each first through hole 60 . Furthermore, in the first overlapping portion 91 where the first bent portions 84 of the plurality of first heat transfer tubes 80 are arranged to overlap each other vertically while being close to the first closing member 50, the surface of the upper first heat transfer tube 80 is covered with The drained water tends to run down along the first heat transfer tube 80 on the lower side. However, in this configuration, the first covering member 50 is located on the lower end side of the first closing member 50 and is located between the first overlapping portion 91 closest to the first group of through holes 60 in the front-rear direction and the first group of through holes 61 . At least one first connecting member 54 (specifically, a first connecting member 54A) is fixed to the area AR1. Therefore, at least the first connecting member 54 (specifically, the first connecting member 54A) avoids contact with the drain hanging from the surface of the first heat transfer tube 80, and the first closing member 50 The lower end side can be fixed.

Furthermore, in the secondary heat exchanger 10, one side of each of the plurality of second heat transfer tubes 180 in the front-rear direction is attached corresponding to the third through-hole 160 of each of the third through-hole groups 161. Drain adhered to the surface of the second heat transfer tube 180 tends to drip along the inner surface of the second closing member 150 from the vicinity of each third through hole 160 . Furthermore, in a second overlapping portion 191 where the second bent portions 184 of the plurality of second heat transfer tubes 180 are arranged to overlap each other vertically while being close to the second closing member 150, The drained water tends to drip down along the second heat transfer tube 180 on the lower side. However, in this configuration, in the area on the lower end side of the second closing member 150 , the fourth fourth portion between the second overlapping portion 191 closest to the third through hole group 161 in the front-rear direction and the third through hole group 161 . At least one second connecting member 154 (specifically, the second connecting member 154) is fixed to the area AR4. Therefore, at least the second connecting member 154 (specifically, the second connecting member 154A) avoids the contact of the drain hanging from the surface of the second heat transfer tube 180, and the second closing member 150 The lower end side can be fixed.

Therefore, according to the secondary heat exchanger 10, it is possible to suppress contact of the drain with the first connecting member 54 that connects the first closing member 50 to the box 31, and the second closing member 150 can be Contact of the drain with the second connecting member 154 connected to the box 31 can be suppressed.

Furthermore, in the secondary heat exchanger 10, the first overlapping portion 91 (specifically, the first first overlapping portion) is the region on the lower end side of the first closing member 50 and is closest to the second through hole group 63 in the front-rear direction. At least one first connecting member 54 (specifically, first connecting member 54B) is also fixed to the second region AR2 between the overlapping portion 91B) and the second through-hole group 63 . Therefore, the lower end side of the first closing member 50 can be more stably fixed while suppressing contact of the drain hanging from the surface of the first heat transfer tube 80 with the first connecting member 54 .

Furthermore, since the first overlapping portion 91 is close to the first bulging portion 65 , in a configuration that can suppress contact of the drain with the first connecting member 54 , an increase in the size of the box 31 is suppressed, and the The total length of one heat transfer tube 80 can be increased.

Furthermore, the first overlapped portion 91 enters into the first swelling portion 65 . According to this configuration, the total length of the heat transfer tube can be further increased.

Furthermore, according to the secondary heat exchanger 10, the first closing member 50 is closed at a total of three points: two points on the downstream side of the first closing member 50 and one point on the upper end side located between these two points. Since it can be fixed, the first closing member 50 can be stably fixed with a small number of the first connecting members 54 .

<Other Examples>
The present invention is not limited to the embodiments illustrated by the above description and drawings, and the following examples are also included in the technical scope of the present invention.

In the above-described embodiment, the secondary heat exchanger 10 is configured to include both the first heat transfer tube portion 12 and the second heat transfer tube portion 112, but the first heat transfer tube portion 12 and the second heat transfer tube portion 112 It is good also as a structure provided with any one. In this case, it is not necessary to provide the partition plate 55 . Further, when only the first heat transfer tube portion 12 of the first heat transfer tube portion 12 and the second heat transfer tube portion 112 is provided, there is no need to provide the third opening 140 . Further, if only the second heat transfer tube portion 112 of the first heat transfer tube portion 12 and the second heat transfer tube portion 112 is provided, it is not necessary to provide the second opening 40 .

10 Secondary heat exchanger (latent heat recovery type heat exchanger for gas appliances)
12... First heat transfer tube portion (heat transfer tube portion, first heat transfer tube portion)
DESCRIPTION OF SYMBOLS 30... Case 31... Box body 32... Main-body part 33... Lid part 35... 1st opening part 36... Surrounding wall part 37... Bottom wall part 38... Discharge port part 39... Inlet part 40... Second opening part 50... First 1st Closing member (closing member, first closing member)
54... First connecting member (connecting member, first connecting member)
60... First through hole 61... First through hole group 62... Second through hole 63... Second through hole group 80... First heat transfer tube (heat transfer tube, first heat transfer tube)
90... First assembly (assembly, first assembly)
91... First overlapping portion (overlapping portion, first overlapping portion)
DESCRIPTION OF SYMBOLS 112... 2nd heat-transfer-tube part 140... 3rd opening part 150... 2nd closing member 154... 2nd connection member 160... 3rd through-hole 161... 3rd through-hole group 162... 4th through-hole 163... 4th through-hole Group 180 Second heat transfer tube 190 Second assembly 191 Second overlapping portion PS Passing space AR1 First area AR2 Second area AR3 Third area AR4 Fourth area

Claims (6)

A box having a main body provided with a first opening at an upper end thereof, and a lid attached to the main body so as to close the first opening, wherein the box contains exhaust gas. a case configured as a passage space;
a heat transfer tube portion including a plurality of heat transfer tubes accommodated in the case;
A latent heat recovery type heat exchanger for a gas appliance having
The main body is
a peripheral wall portion surrounding the passage space;
a bottom wall portion provided on the lower end side of the peripheral wall portion;
has
In the peripheral wall portion, an exhaust gas outlet is provided on one side in the front-rear direction, an inflow port for exhaust gas passing through the passage space is provided on the other side in the front-rear direction, and a second opening is provided on one side in the left-right direction. is provided,
Said case is
a plate-like closing member that closes the second opening;
a connecting member that connects the closing member and the peripheral wall;
has
The closing member includes a first through-hole group including a plurality of first through-holes and a second through-hole group including a plurality of second through-holes. A group of holes are arranged apart in the front-rear direction,
Each of the plurality of heat transfer tubes is attached so that one side in the front-rear direction corresponds to each of the first through holes of the first through-hole group, and the other side in the front-rear direction is attached to each of the second through-hole groups. is attached correspondingly to the second through-hole of and is fixed to the closure member in a configuration in which each bent portion is disposed in proximity to the closure member;
An assembly in which the heat transfer tube portion and the closing member are integrally assembled has a configuration in which a plurality of the heat transfer tubes are inserted into the box from the second opening, and the second opening is connected to the closing member. The closing member is fixed to the peripheral wall portion by the connecting member while being arranged in a configuration closed by
One or more overlapping portions are provided in which the bent portions of the plurality of heat transfer tubes overlap vertically while being close to the closing member,
At least one connecting member is provided in a region on the lower end side of the closing member and between the overlapping portion closest to the first through hole group in the front-rear direction and the first through hole group. Latent heat recovery heat exchanger for stationary gas appliances. At least one connecting member is provided in a region on the lower end side of the closing member and between the overlapping portion closest to the second group of through holes in the front-rear direction and the second group of through holes. The latent heat recovery type heat exchanger for gas appliances according to claim 1, wherein the latent heat recovery type heat exchanger is fixed. The closing member has a plate-like portion arranged along the vertical direction and the front-rear direction, and a bulging portion that bulges outward in the left-right direction from the plate-like portion,
The latent heat recovery heat exchanger for gas appliances according to claim 1 or 2, wherein the overlapping portion is adjacent to the bulging portion. The latent heat recovery heat exchanger for gas appliances according to any one of claims 1 to 3, wherein the overlapping portion is located inside the bulging portion. At least one 3. The latent heat recovery type heat exchanger for gas appliances according to claim 2, wherein the two connecting members are fixed. A box having a main body provided with a first opening at an upper end thereof, and a lid attached to the main body so as to close the first opening, wherein the box contains exhaust gas. a case configured as a passage space;
a first heat transfer tube portion including a plurality of first heat transfer tubes accommodated in the case;
a second heat transfer tube portion including a plurality of second heat transfer tubes accommodated in the case;
A latent heat recovery type heat exchanger for a gas appliance having
The main body is
a peripheral wall portion surrounding the passage space;
a bottom wall portion provided on the lower end side of the peripheral wall portion;
has
In the peripheral wall portion, an exhaust gas outlet portion is provided on one side in the front-rear direction, an inflow port portion for exhaust gas passing through the passage space is provided on the other side in the front-rear direction, and a second peripheral wall portion is provided on one side in the left-right direction. An opening is provided, and a third opening is provided on the other side in the left-right direction,
Said case is
a plate-shaped first closing member that closes the second opening;
a plate-shaped second closing member that closes the third opening;
a first connecting member that connects the first closing member and the peripheral wall;
a second connecting member that connects the second closing member and the peripheral wall;
has
The first closing member includes a first through-hole group including a plurality of first through-holes and a second through-hole group including a plurality of second through-holes. two groups of through-holes are spaced apart in the front-rear direction,
The second closing member is provided with a third through-hole group including a plurality of third through-holes and a fourth through-hole group including a plurality of fourth through-holes. 4 through-hole groups are arranged apart in the front-rear direction,
Each of the plurality of first heat transfer tubes is attached on one side in the front-rear direction so as to correspond to each of the first through holes of the first through-hole group, and is attached on the other side in the front-rear direction to the second through-hole group. is attached corresponding to each of the second through-holes, and is fixed to the first closing member in a configuration in which the first bending portion, which is each bending portion, is arranged in proximity to the first closing member,
Each of the plurality of second heat transfer tubes is attached on one side in the front-rear direction so as to correspond to each of the third through holes of the third through-hole group, and is attached on the other side in the front-rear direction to the fourth through-hole group. and fixed to the second closing member in a configuration in which the second bending portion, which is each bending portion, is arranged in proximity to the second closing member,
A first assembly in which the first heat transfer tube portion and the first closing member are integrally assembled inserts a plurality of the first heat transfer tubes into the box from the second opening; The first closing member is fixed to the peripheral wall portion by the first connecting member while being arranged in a configuration in which the second opening is closed by the first closing member,
A second assembled body in which the second heat transfer tube portion and the second closing member are integrally assembled inserts a plurality of the second heat transfer tubes into the box from the third opening; The second closing member is fixed to the peripheral wall portion by the second connecting member while the third opening is closed by the second closing member, and
One or more first overlapping portions are provided in which the first bending portions of the plurality of first heat transfer tubes overlap vertically while being close to the first closing member,
One or more second overlapping portions are provided in which the second bent portions of the plurality of second heat transfer tubes overlap vertically while being close to the second closing member,
At least one The first connecting member is fixed,
At least one A latent heat recovery type heat exchanger for a gas appliance, to which the second connecting member is fixed.

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