Method of producing water heater, and method of determining position of partition part

Abstract

To provide a method of producing a water heater capable of preventing a burner unit from being scorched by a flame of the burner unit, and a method of determining the position of a partition part.SOLUTION: Cooling spaces 91, 92 are each respectively disposed between outer burner units 51, 51 each respectively positioned on either of the left and right sides of a unit group 23, and each of a right wall 31 and a left wall 32, to allow the combustion air to flow from below to above. Partition walls 425, 435 are each disposed in a specified region in the swirl flows of the combustion air each generated in the cooling spaces 91, 92 respectively. The specified region is a region determined by a simulation for the combustion air to flow downward therein. The partition walls 425, 435 each partition the cooling spaces 91, 92 respectively, in the front and rear direction. Thereby, the downward flows are each divided by the partition walls 425, 435 respectively in the front and rear direction to weaken the downward flows. Hence, the upward flows of the combustion air become dominant to suppress the generation of swirl flows in the cooling spaces 91, 92.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a water heater and a method for determining the position of a partition portion.

Background Art

[0002] The water heater described in Patent Document 1 includes a combustion device and a heat exchanger in a housing. The combustion device includes a unit group and an inner case. The unit group includes a plurality of burner units arranged side by side in the left - right direction, ignites a mixture of gas and combustion air, and burns. The inner case houses the unit group inside. The heat exchanger is arranged above the combustion device and heats the flowing water with the combustion exhaust gas of the unit group.

[0003] An opening is provided on the lower surface of the inner case. The opening takes in the combustion air blown from a fan. A support plate and a lower plate portion are assembled inside the inner case. The support plate is formed in a U - shape in plan view and supports the unit group inside. The lower plate portion vertically partitions the space inside the inner case and is arranged below the unit group. A plurality of small holes are provided in the lower plate portion. The plurality of small holes supply combustion air to the side of the plurality of burner units arranged side by side in the left - right direction. A front plate portion extending upward is provided at the front end portion of the lower plate portion. The front plate portion is arranged on the front side of the unit group and supports the front portions of the respective plurality of burner units.

[0004] A cooling space is provided between the inner surfaces of the side wall portions on both the left and right sides of the inner case and the burner units on both the left and right sides of the unit group. The cooling space branches a part of the combustion air taken into the inner case from the opening to both the left and right sides of the unit group, and passes the cooling air from below to above to prevent overheating of the combustion device.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the combustion device having the above configuration, there was a problem that partial burning occurred in the burner units on both the left and right sides of the unit group. When investigating the cause, it was found that in the cooling space, a backward vector was imparted to the air flowing from the lower side to the upper side by the front plate portion, and a vortex was generated by flowing downward at the rear side of the cooling space. Due to the downward flow of this vortex, the flames of the burner units on both the left and right sides of the unit group were pushed downward, and as a result, it was presumed that the burner units on both the left and right sides were burned.

[0007] An object of the present invention is to provide a method for manufacturing a water heater and a method for determining the position of a partition portion that can prevent the burner unit from being burned by the flame of the burner unit.

Means for Solving the Problems

[0008] The method for manufacturing a water heater according to claim 1 includes a unit group in which a plurality of burner units are arranged side by side in the left - right direction, a rear wall portion, a pair of left - right side wall portions extending forward from both the left and right ends of the rear wall portion, a bottom wall portion connected to the rear wall portion and the pair of left - right side wall portions and closing the lower surface, an opening provided in the bottom wall portion for taking in air supplied from a fan provided below the bottom wall portion, an inner case that houses the unit group inside, a support portion provided inside the inner case for supporting the unit group so as to sandwich it from the front - rear direction, outer burner units located on both the left and right sides among the plurality of burner units of the unit group, and a cooling space provided between each of the pair of left - right side wall portions and supplied with the air taken into the inner case from the opening. The method for manufacturing a water heater is characterized by including a first step of specifying, by a test or an experiment, a region of a downward flow among vortices including upward and downward flows of the air generated in the cooling space, and a second step of providing a partition wall that partitions the cooling space in the front - rear direction and divides the downward flow in the region specified in the first step.

[0009] In the method for manufacturing a water heater according to claim 2, the test or experiment may be a test or experiment in which the flow velocity of combustion air is measured using a sensor while the water heater is in operation.

[0010] In the method for manufacturing a water heater according to claim 3, the test or experiment may be a test or experiment in which a model of the water heater is constructed on a computer and simulated using the model.

[0011] The method for determining the position of the partition part according to claim 4 is a method for determining the position of the partition part in the cooling space of a water heater, comprising: an inner case that houses the unit group inside, the unit group being formed by a plurality of burner units arranged side by side in the left-right direction; a rear wall part; a pair of left and right side wall parts extending forward from both left and right ends of the rear wall part; a bottom wall part connected to the rear wall part and the pair of left and right side wall parts and closing the lower surface; an opening provided in the bottom wall part for taking in air supplied from a fan provided below the bottom wall part; a support part provided inside the inner case for supporting the unit group so as to sandwich it from the front-rear direction; outer burner units located on both left and right sides among the plurality of burner units of the unit group; a cooling space provided between each of the pair of left and right side wall parts and into which the air taken into the inner case from the opening is supplied; and a partition part provided in the cooling space for partitioning the cooling space in the front-rear direction. The method for determining the position of the partition part includes a specifying step of specifying, by a test or experiment, a region flowing downward among the vortices including the upward and downward flows of the air generated in the cooling space, and a determining step of determining the position of the partition part within the region specified in the specifying step.

[0012] In the method for determining the position of the partition part according to claim 5, the test or experiment may be a test or experiment in which the flow velocity of combustion air is measured using a sensor while the water heater is in operation.

[0013] In the method for determining the position of the partition part according to claim 6, the test or experiment may be a test or experiment in which a model of the water heater is constructed on a computer and simulated using the model.

Advantages of the Invention

[0014] According to the method for manufacturing a water heater of claim 1, in the cooling space, a partition part is arranged in a region specified as a region where a downward flow is generated according to the test or experiment result. In the region where the downward flow is generated, a part of the air from the fan flows in at the same time. However, in the state without the partition part, since the downward vector of the vortex is relatively stronger than the upward vector of the air flowing in from below, a downward flow is generated. By arranging the partition part in such a region, the downward flow can be surely divided in the front-rear direction. As a result, the downward flow is weakened, so that the flame of the burner unit does not face downward. Therefore, the water heater manufactured by the manufacturing method of the present invention can prevent the burner unit from being burned by the flame of the burner unit.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0016] Hereinafter, embodiments of the present invention will be described. The device configurations and the like described below are not intended to be limited to only those, without specific description, but are merely illustrative examples. The drawings are used to explain the technical features that the present invention can adopt.

[0017] Referring to FIG. 1, the configuration of the water heater 1 will be described. In the square box-shaped housing 2 of the water heater 1, a combustion device 3, a heat exchanger 4, and an exhaust hood 5 are installed in order from below. A gas supply unit 6 is assembled on the front surface of the combustion device 3. The gas supply unit 6 distributes and supplies gas to a unit group 23 described later in the combustion device 3. A fan 7 is assembled on the lower surface of the combustion device 3. The fan 7 supplies combustion air to the combustion device 3. A controller 8 formed by housing an electrical control board is erected horizontally on the inner bottom surface of the housing 2 below the front side of the fan 7 and below the combustion device 3. The heat exchanger 4 includes a plurality of fins (not shown) inside the casing at a predetermined interval in the left-right direction, and a heat transfer tube 9 that penetrates each fin in a meandering shape, and performs heat exchange between the combustion exhaust passing between the fins from below and the water flowing in the heat transfer tube 9. The exhaust hood 5 includes a horizontally long oval exhaust pipe 10 on the front surface. The exhaust pipe 10 penetrates a front cover (not shown) and protrudes forward, and discharges the combustion exhaust that has passed through the heat exchanger 4 to the outside.

[0018] A gas inlet 11, a water inlet 12, and a hot water outlet 13 are provided on the lower surface of the housing 2. An external gas pipe (not shown) is connected to the gas inlet 11. A water pipe (not shown) is connected to the water inlet 12. A pipe (not shown) to a hot water tap is connected to the hot water outlet 13. The gas inlet 11 is connected to the gas supply unit 6 via a gas pipe 14 provided with an original valve, a proportional valve, etc. inside the housing 2. The water inlet 12 is connected to the upstream end of the heat transfer tube 9 of the heat exchanger 4 via a water supply pipe 15. The hot water outlet 13 is connected to the downstream end of the heat transfer tube 9 via a hot water outlet pipe 16.

[0019] Referring to FIGS. 2 to 4, the structure of the combustion device 3 will be described. The combustion device 3 includes a rectangular box-shaped inner case 20. The inner case 20 is housed in the housing 2. Inside the inner case 20, a unit group 23 is assembled. The unit group 23 includes a plurality of flat burner units 51 stacked in the left-right direction and has a substantially rectangular parallelepiped shape. The inner case 20 includes a case body 21 and a front wall 25 and is made of metal (for example, aluminized steel sheet). The case body 21 has an open upper surface and front surface. The front wall 25 is assembled to the front surface of the case body 21. The unit group 23 is fixed inside the case body 21 via the front and rear inner plates 24 and the support plate 22.

[0020] The case body 21 includes a right wall portion 31, a left wall portion 32, a rear wall portion 33, a bottom wall portion 34, and a heat prevention plate 38. At the upper end of the rear wall portion 33 and at the upper ends of the right wall portion 31 and the left wall portion 32 respectively, a rising portion 36 is bent upward over the entire length. The rising portion 36 has a substantially L-shaped cross section. A plurality of caulking pieces 37 are provided at predetermined intervals on each rising portion 36. At the front ends of the right wall portion 31 and the left wall portion 32 respectively, fixing pieces 311, 321 are bent outward. The front wall 25 and the gas supply unit 6 are screwed to the fixing pieces 311, 321. An opening 35 to which a fan 7 is connected is provided in the bottom wall portion 34. The heat prevention plate 38 is a horizontally long rectangular metal plate (for example, a stainless steel plate) and is attached so as to cover the upper side portion of the inner surface of the rear wall portion 33 with a gap. A bulging portion 331 projects rearward from the rear wall portion 33 below the heat prevention plate 38. The bulging portion 331 is a horizontally long rectangular shape extending in the left-right direction.

[0021] The support plate 22 includes a back plate portion 40, a right plate portion 42, and a left plate portion 43, and is formed in a substantially U-shaped shape in plan view that opens forward. The back plate portion 40 is horizontally long and rectangular in front view and is provided along the inner surface of the rear wall portion 33. The right plate portion 42 and the left plate portion 43 are bent forward from the right end portion and the left end portion of the back plate portion 40. A fitting portion 44 projects rearward from the back plate portion 40. The fitting portion 44 has the same shape as the bulging portion 41 and fits into the bulging portion 41 from the front. A plurality of support pieces 45 are bent forward at equal intervals in the left-right direction at the upper end edge of the back plate portion 40. A slit 45A is provided between each support piece 45 at the upper end edge of the back plate portion 40. The slit 45A is a downward cut. A plurality of support pieces 46 are also bent forward at equal intervals in the left-right direction at the lower end edge of the back plate portion 40. The plurality of support pieces 45 and 46 engage between the respective burner units 51 of the unit group 23.

[0022] The right plate portion 42 and the left plate portion 43 have a left-right width in which the unit group 23 can fit and extend forward inside the right wall portion 31 and the left wall portion 32. The right plate portion 42 includes, in order from the rear side to the front side, an extension portion 421, a stepped portion 422, and a contact portion 423. The extension portion 421 extends forward from the right end portion of the back plate portion 40 to a position corresponding to the front side portion of the unit group 23. The stepped portion 422 is bent rightward from the front end portion of the extension portion 421 and extends rightward. The contact portion 423 is bent forward from the right end portion of the stepped portion 422 and extends forward to contact the inner surface of the right wall portion 31. The left plate portion 43 also includes, in order from the rear side to the front side, an extension portion 431, a stepped portion 432, and a contact portion 433. The extension portion 431 also extends forward from the left end portion of the back plate portion 40 to a position corresponding to the front side portion of the unit group 23. The stepped portion 432 is bent leftward from the front end portion of the extension portion 431 and extends leftward. The contact portion 433 is bent forward from the left end portion of the stepped portion 432 and extends forward to contact the inner surface of the left wall portion 32. At the front end of each of the right plate portion 42 and the left plate portion 43, mounting pieces 47 and 48 having screw holes 471 and 481 are bent inward.

[0023] A partition wall 425 is provided at a substantially middle portion in the front-rear direction on the right surface of the extended portion 421 of the right plate portion 42. The partition wall 425 protrudes to the right and is formed in a substantially rectangular shape that is long in the vertical direction when viewed from the front. The right end portion of the partition wall 425 contacts the inner surface of the right wall portion 31 (see FIGS. 3 and 4). A partition wall 435 is also provided at a substantially middle portion in the front-rear direction on the left surface of the extended portion 431 of the left plate portion 43. The partition wall 435 protrudes to the left and is formed in a substantially rectangular shape that is long in the vertical direction when viewed from the front. The left end portion of the partition wall 435 contacts the inner surface of the left wall portion 32 (see FIG. 3). Note that the partition walls 425 and 435 may be fixed to the right surface of the extended portion 421 and the left surface of the extended portion 431, respectively, by screwing, welding, or the like.

[0024] The support plate 22 is attached to the rear wall portion 33 with a rivet (not shown) at a position where the fitting portion 44 fits into the bulging portion 331. The upper portion of the support plate 22 overlaps the lower portion of the heat prevention plate 38 from the front and presses and fixes the lower portion of the heat prevention plate 38 toward the rear wall portion 33 side. Each slit 45A of the support plate 22 extends below the lower end of the heat prevention plate 38 and communicates with a gap generated between the inner surface of the rear wall portion 33 and the heat prevention plate 38.

[0025] Each burner unit 51 of the unit group 23 is a well-known lean-rich burner. The burner unit 51 includes a lean-side inlet 53, a rich-side inlet 54, a mixing portion 55, and a flame hole portion 56. The lean-side inlet 53 is an opening on the lower side that opens forward and into which fuel gas and primary air are introduced. The rich-side inlet 54 is an opening on the upper side. The mixing portion 55 is provided on the downstream side of the lean-side inlet 53 and the rich-side inlet 54, and the interior is separated for each inlet. The flame hole portion 56 opens at the upper end of the mixing portion 55 and includes a central lean flame hole and rich flame holes on both the left and right sides thereof.

[0026] The inner plate 24 includes a lower plate portion 61 and a front plate portion 62, and is substantially L-shaped in side view. The lower plate portion 61 is located below the unit group 23. The front plate portion 62 is located in front of the unit group 23. A plurality of small holes 611 are formed at predetermined intervals in the front, rear, left, and right directions on the lower plate portion 61. At the rear end of the lower plate portion 61, a screw fixing piece 612 is formed by bending downward. The screw fixing piece 612 is screwed to the rear wall portion 33 by two screws 81 and 82 from the front. At the right and left edges of the lower plate portion 61, downwardly bent pieces 63 and 64 are formed. The downwardly bent pieces 63 and 64 abut against the inner surfaces of the right wall portion 31 and the left wall portion 32, respectively.

[0027] At the upper edge of the front plate portion 62, a plurality of support pieces 65 are formed by bending rearward at equal intervals in the left-right direction. The plurality of support pieces 65 engage between the respective burner units 51 of the unit group 23. Thereby, the unit group 23 is sandwiched and supported between the front plate portion 62 of the inner plate 24 and the back plate portion 40 of the support plate 22. Therefore, the combustion device 3 can stably support the unit group 23 so as to sandwich it from the front and rear directions.

[0028] Below the plurality of support pieces 65, a plurality of pairs of light gas supply holes 66 and rich gas supply holes 67 are arranged in parallel in the left-right direction. The lower light gas supply holes 66 are oval burring holes and correspond to the light side inlets 53 of the respective burner units 51. The upper rich gas supply holes 67 are circular burring holes and correspond to the rich side inlets 54 of the respective burner units 51. Thereby, the combustion device 3 can supply gas to each of the plurality of burner units 51 through the plurality of light gas supply holes 66 and rich gas supply holes 67. Also, at the right and left ends of the front plate portion 62, forwardly bent pieces 68 and 69 are formed. The forwardly bent pieces 68 and 69 abut against the inner surfaces of the right wall portion 31 and the left wall portion 32, respectively. Fixing holes 623 and 624 are provided at the middle portions in the height direction on the right end side and the left end side of the front plate portion 62, respectively. Inside the forwardly bent pieces 68 and 69, the mounting pieces 47 and 48 of the support plate 22 abut against the back surface of the front plate portion 62, and screws 83 and 84 are tightened and fixed from the front to the screw holes 471 and 481 of the mounting pieces 47 and 48 through the fixing holes 623 and 624.

[0029] The front wall 25 is horizontally long rectangular and covers the upper half of the front surface of the case body 21. A rising portion 74 is provided at the upper edge of the front wall 25. The rising portion 74 is formed by bending upward over the entire length of the upper edge of the front wall 25 and has a substantially L-shaped cross section. A plurality of caulking pieces 75 are arranged side by side in the left-right direction at predetermined intervals on the rising portion 74. In the middle portion of the front wall 25 in the height direction, mounting holes 71, mounting holes 72, and through holes 73 are provided at predetermined intervals in order from the right side to the left side. A discharge electrode (not shown) for ignition is attached to the mounting hole 71. A frame rod (not shown) as a flame detection electrode is attached to the mounting hole 72. A viewing window (not shown) is attached to face the through hole 73. The front wall 25 having the above shape is fixed to the front plate portion 62 of the inner plate 24 with screws 89 from the front and is also fixed to the fixing pieces 311, 312 of the case body 21 with screws 87, 88 from the front.

[0030] As shown in FIG. 3, inside the inner case 20, cooling spaces 91, 92 are provided between the burner units 51, 51 located on the left and right sides of the unit group 23 and the inner surfaces of the right wall portion 31 and the left wall portion 32 of the case body 21, respectively. The cooling spaces 91, 92 prevent overheating of the unit group 23 by passing the primary air for combustion taken into the inner case 20 from the opening 35 of the bottom wall portion 34 upward as cooling air from below. A partition wall 425 is arranged at the rear side in the right cooling space 91 (see FIG. 5). The partition wall 425 partitions the cooling space 91 in the front-rear direction. A partition wall 435 is arranged at the rear side in the left cooling space 92. The partition wall 435 partitions the cooling space 92 in the front-rear direction. The specific positions and functions of the partition walls 425, 435 will be described later.

[0031] Referring to FIGS. 2 to 7, the eddy currents of the cooling air generated in the cooling spaces 91 and 92 will be described. FIG. 6 is an analysis diagram simulating the air flow velocity in the cooling space 92 without the partition wall 435 during the operation of the water heater. FIG. 7 is an analysis diagram simulating the air flow velocity in the cooling space 92 with the partition wall 435 during the operation of the water heater 1. The darker the color area, the higher the air flow velocity (Velocity[K] (m / s)). The thick white arrows in FIGS. 6 and 7 indicate the air flow. Note that the simulation results in the cooling space 91 are omitted because they are almost the same as the simulation results in the cooling space 92.

[0032] As shown in FIGS. 2 and 3, the air blown upward from the fan 7 flows into the inner case 20 through the opening 35 of the bottom wall portion 34. The inflowing air is rectified by a plurality of small holes 611 provided in the lower plate portion 61 of the inner plate 24 and supplied as secondary air to the unit group 23 side. Thereby, the combustion efficiency at each flame hole portion 56 of the plurality of burner units 51 can be improved. On the other hand, the other air branches to both the left and right sides of the lower plate portion 61 and is deflected upward by the right wall portion 31 and the left wall portion 32 of the case body 21 and flows into the cooling spaces 91 and 92. The air flows upward through the cooling spaces 91 and 92 as cooling air.

[0033] As shown in the experimental results of FIG. 6, it was found that in the state where there is no partition wall 435 in the cooling space 92, an eddy current of the cooling air is generated in the cooling space 92. The eddy current is a flow of a vortex that rises at the front side and descends at the rear side. Specifically, when air flows into the inner case 20 through the opening 35 provided behind the bottom wall portion 34, it rises while diffusing forward in the cooling space 92 (see (1) in FIG. 6). At this time, it is deflected by the front plate portion 62 of the inner plate 24 and a backward vector is applied (see (2) in FIG. 6). Then, a part of the cooling air deflected backward contacts the rear wall portion 33 of the case body 21 and flows downward (see (3) in FIG. 6). In the region P where a downward flow is presumed to occur, at the same time, a part of the air from the fan 7 flows upward through the opening 35 of the bottom wall portion 34.

[0034] Here, in region P, the downward vector of the air is relatively stronger than the upward vector of the air flowing in from the opening 35 of the bottom wall portion 34. Therefore, since the downward flow is dominant in region P, it is presumed that a vortex flow as shown in FIG. 6 is generated. The downward flow due to the vortex flow pushes down the flames of the burner units 51 located on both the left and right sides of the unit group 23, so there is a possibility that the side surfaces of the burner units 51 are scorched and burned.

[0035] Therefore, in the combustion apparatus 3 of the present embodiment, partition walls 425 and 435 are respectively arranged in the regions P where the downward flow of air occurs in the cooling spaces 91 and 92. The partition walls 425 and 435 partition the cooling spaces 91 and 92 in the front-rear direction. As a result, as shown in the experimental results of FIG. 7, since the downward flow in region P is divided into front and rear by the partition wall 435, it can be made into a relatively weak flow. Thus, since it loses to the upward flow of the air flowing in from the opening 35 of the bottom wall portion 34, it consequently has an upward tendency. Thereby, since the combustion apparatus 3 can effectively suppress the generation of vortex flow in the cooling spaces 91 and 92, it can prevent the burner units 51 on both the left and right sides of the unit group 23 from being scorched by their own flames and causing burning.

[0036] As described above, the water heater 1 manufactured by the manufacturing method of the present embodiment includes a unit group 23, an inner case 20, a support plate 22, an inner plate 24, cooling spaces 91 and 92, and partition walls 425 and 435. The unit group 23 is configured by arranging a plurality of burner units 51 side by side in the left-right direction. The inner case 20 includes a right wall portion 31, a left wall portion 32, a rear wall portion 33, a bottom wall portion 34, and an opening 35, and houses the unit group 23 inside. The right wall portion 31 and the left wall portion 32 extend forward from the right end and the left end of the rear wall portion 33, respectively. The bottom wall portion 34 is connected to each of the right wall portion 31, the left wall portion 32, and the rear wall portion 33 to close the lower surface. The opening 35 is provided in the bottom wall portion 34 and takes in combustion air supplied from a fan 7 provided below the bottom wall portion 34. The support plate 22 and the inner plate 24 are provided inside the inner case 20 and support the unit group 23 so as to sandwich it from the front and rear directions. The cooling spaces 91 and 92 are provided between the outer burner units 51 and 51 located on both the left and right sides among the plurality of burner units 51 of the unit group 23 and the right wall portion 31 and the left wall portion 32, respectively, and allow the combustion air taken into the inner case 20 from the opening 35 to pass from below upward. The partition walls 425 and 435 are provided in a region P within the vortices of the combustion air generated in the cooling spaces 91 and 92. The region P is a region in which the combustion air flows downward, which is specified by simulation. The partition walls 425 and 435 partition the cooling spaces 91 and 92 in the front-rear direction.

[0037] In the region P where the downward flow is occurring, a part of the combustion air from the fan 7 simultaneously flows in. By arranging the partition walls 425 and 435 within the region P, the downward flow is divided in the front-rear direction by the partition walls 425 and 435. As a result, the downward flow weakens and the upward flow of the combustion air becomes dominant, so that the generation of vortices can be effectively suppressed. Therefore, the water heater 1 can prevent the burner unit 51 from being burned by the flame of the burner unit 51 in the combustion device 3.

[0038] In the above description, the right wall portion 31 and the left wall portion 32 of the inner case 20 are an example of the "pair of left and right side wall portions" of the present invention. The opening 35 is an example of the "opening" of the present invention. The support plate 22 and the inner plate 24 are an example of the "support portion" of the present invention. The partition walls 425 and 435 are an example of the "partition portion" of the present invention. The burner unit 51 is an example of the "burner" of the present invention.

[0039] Note that the present invention is not limited to the above-described embodiment, and various modifications are possible. In the above embodiment, the partition walls 425 and 435 are fixed to the right plate portion 42 and the left plate portion 43 of the support plate 22, so that the partition walls 425 and 435 are arranged in a predetermined region P within the cooling spaces 91 and 92. However, the partition walls may be provided on members other than the support plate 22, for example, on the inner surfaces of the right wall portion 31 and the left wall portion 32 of the inner case 20.

[0040] In the above embodiment, the unit group 23 is supported by sandwiching it from the front and rear directions by the back plate portion 40 of the support plate 22 and the front plate portion 62 of the inner plate 24. However, it may be supported by other methods. For example, the direction, position, and structure for supporting the unit group 23 can be freely changed. Note that it is desirable to provide the cooling spaces 91 and 92 on both the left and right sides of the unit group 23.

[0041] The position and shape of the opening 35 in the bottom wall portion 34 are not limited to the position and shape of the above embodiment. Although there is one opening 35, a plurality of openings may be provided. Depending on the position, shape, size, number, etc. of the opening 35, the flow of the cooling air in the cooling spaces 91 and 92 changes. Therefore, it is advisable to check the generation of the vortex and the position of the region P for each water heater and adjust the positions of the partition walls 425 and 435 respectively.

[0042] The partition walls 425 and 435 are parallel in the left-right direction. However, within the region P, as long as the cooling spaces 91 and 92 can be partitioned in the front-rear direction, the shape is not limited. For example, it may be inclined with respect to the left-right direction. Furthermore, it does not have to be in a flat plate shape and may be curved or bent.

[0043] The water heater 1 is a normal water heater equipped with one heat exchanger 4, but it may also be a latent heat type water heater equipped with two heat exchangers for sensible heat recovery and latent heat recovery. The inner plate 24 is substantially L-shaped in side view with the lower plate portion 61 and the front plate portion 62 integrated, but they may also be separate.

Explanation of Signs

[0044] 1 Water heater 3 Combustion device 7 Fan 20 Inner case 22 Support plate 23 Unit group 24 Inner plate 31 Right wall portion 32 Left wall portion 33 Rear wall portion 34 Bottom wall portion 35 Opening 40 Rear plate portion 45 Support piece 51 Burner unit 61 Lower plate portion 62 Front plate portion 65 Support piece 66 Lean gas supply hole 67 Rich gas supply hole 91, 92 Cooling space 425, 435 Partition wall

Claims

1. A unit group including a plurality of burner units arranged in parallel in the left-right direction; an inner case that houses the group of units and includes a rear wall portion, a pair of left and right side wall portions extending forward from left and right ends of the rear wall portion, a bottom wall portion that is connected to the rear wall portion and the pair of left and right side wall portions and closes a lower surface, and an opening that is provided in the bottom wall portion for taking in air supplied from a fan provided below the bottom wall portion; a support portion provided inside the inner case and configured to support the unit group in a sandwiching manner from the front and rear directions; a cooling space provided between each of the outer burner units located on both the left and right sides of the plurality of burner units of the unit group and each of the pair of left and right side wall portions, the cooling space being supplied with the air taken into the inner case through the opening; A method for manufacturing a water heater comprising: A step of identifying, by a test or an experiment, a region of the vortex including the upward and downward flows of the air generated in the cooling space that flows downward; an installation step of installing a partition wall in the region identified in the identification step, the partition wall dividing the cooling space in a front-rear direction and isolating the downward flow; A method for manufacturing a water heater comprising the steps of:

2. The test or experiment is a test or experiment in which the flow rate of the combustion air is measured using a sensor while the water heater is in operation. A method for manufacturing the water heater according to claim 1.

3. The test or experiment involves constructing a model of the water heater on a computer and conducting a simulation using the model. A method for manufacturing the water heater according to claim 1.

4. A unit group including a plurality of burner units arranged in parallel in the left-right direction; an inner case that houses the group of units and includes a rear wall portion, a pair of left and right side wall portions extending forward from left and right ends of the rear wall portion, a bottom wall portion that is connected to the rear wall portion and the pair of left and right side wall portions and closes a lower surface, and an opening that is provided in the bottom wall portion for taking in air supplied from a fan provided below the bottom wall portion; a support portion provided inside the inner case and configured to support the unit group in a sandwiching manner from the front and rear directions; a cooling space provided between each of the outer burner units located on both the left and right sides of the plurality of burner units of the unit group and each of the pair of left and right side wall portions, to which the air taken into the inner case through the opening is supplied; a partition portion provided in the cooling space and dividing the cooling space in a front-rear direction; A method for determining a position of the partition part in the cooling space of a water heater comprising: A step of identifying, by a test or an experiment, a region of the vortex including the upward and downward flows of the air generated in the cooling space that flows downward; a determining step of determining a position of the partition portion within the region identified in the identifying step; A method for determining a partition position, comprising:

5. The test or experiment is a test or experiment in which the flow rate of the combustion air is measured using a sensor while the water heater is in operation.

5. The method for determining a partition position according to claim 4, further comprising the steps of:

6. The test or experiment involves constructing a model of the water heater on a computer and conducting a simulation using the model.

5. The method for determining a partition position according to claim 4, further comprising the steps of:

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